A spray coater is used to spray a photoresist on a front surface of a wafer. The spray coater includes a vacuum chuck, a flow guiding ring, and a positioning ring. The vacuum chuck has a top surface and a side surface adjacent to the top surface. The wafer is located on the top surface and protrudes from the top surface of the vacuum chuck. The flow guiding ring is disposed around the vacuum chuck and has a groove. The wafer protruding from the top surface covers the flow guiding ring, and an opening of the groove faces a back surface of the wafer opposite to the front surface. The positioning ring is disposed around the flow guiding ring, such that the flow guiding ring is between the positioning ring and the side surface of the vacuum chuck.

Field of Invention
The present invention relates to a spray coater and a ring-shaped structure of the spray coater.
Description of Related Art
A typical spray coater includes a vacuum chuck, plural ring-shaped bodies and a nozzle. The ring-shaped bodies surround the vacuum chuck. When a wafer is located on the vacuum chuck, the nozzle can spray photoresist on a front surface of the wafer. In addition, redundant photoresist may flow to the ring-shaped bodies from the wafer. Thereafter, the redundant photoresist flows out of the spray coater from the ring-shaped bodies.
When the photoresist flows to an edge of the wafer from the front surface of the wafer, airflow generated by the vacuum chuck enables the photoresist to flow to a back surface of the wafer from the edge of the wafer, which is referred to as a "vacuum effect". Since the diameter of the wafer is about 10 mm greater than the outer diameter of the innermost ring-shaped body and the innermost ring-shaped body does not have a special design, the photoresist is left on the edge of the back surface of the wafer with a width of about 15 mm. As a result, the photoresist enters a trench of the wafer. In a subsequent manufacturing process, a knife is used to cut the wafer along the trench.
In a subsequent etching process, the photoresist left on the edge of the back surface of the wafer results in photoresist burning (PR burn), thus reducing the yield rate of the wafer. Moreover, the photoresist is also left on the vacuum chuck to cause abnormal vacuuming. In addition, the innermost ring-shaped body is made of aluminum, so that the strength of the innermost ring-shaped body is not enough and is easily deformed. As a result, the reliability of the spray coater is reduced.

Spray coater and ring-shaped structure thereof


An industrial automation system comprising a processor with an updating component coupled to automation devices via a network. The updating component reads control information from machine readable representations of the devices and populates a data structure with the control information. The updating component also updates configuration information of a device from data stored in a file object and/or the data structure, further allowing this transfer to be fragmented into a plurality of messages if the configuration information exceeds a threshold. As well, a vendor deployment methodology is provided that embeds devices and firmware for devices with a Device Type Manager (DTM) prior to deployment and can optionally allow post deployment updates to the DTM.

A DTM (Device Type Manager) and an EDS (Electronic Data Sheet) are both machine readable representations of automation devices. They are typically used by network-centric software tools to present control information about a device to a user for purposes of assisting the user in the configuration of the device's functions.
In addition, these machine readable representations provide information about the sizes and associated structures of I/O data blocks that the device has available for real time I/O exchange with a controller. This information is then used to configure a controller's scanlist for communication with the device. The I/O data blocks typically show up in the controller data table byte or word arrays, with the specific meaning of the various elements of the data and their offset in the block having to be managed manually by the user so that the elements can be used properly with the current control program(s). Typically this mapping of the data elements to functions within the control program has to be done by the user separately for each instance of the device in the control system.
In certain controllers, the user has the option to manually create user defined structures, complete with data typing and specific labels/tags for each of the elements, which then can be applied on a per instance basis for each occurrence of the device. This comes at some expense of time and is therefore typically done only when the user expects to use many such devices in a plant. For example, a device might have, e.g., 10 bytes of input data and 10 bytes of output data as the default format from its device profile, with a function and naming convention for what each of the bits represent. However, new features could be added to the device by a vendor or manufacturer that could, for example, be useful to a customer in a particular application. In conventional systems, in the above situation, the user must add those extra elements in the data structure manually with a software programming tool because they are not in the device profile.
Moreover, even if the system has readily available control information (e.g., from an up-to-date machine readable representation such as a DTM or EDS), the device may still need to have its configuration information updated. For example, when a device gets damaged or stops functioning, maintenance personnel can often adequately perform the necessary procedures to replace the device based upon a catalog number or a part number for the device. Maintenance personnel can install a new device and reconnect it as it previously existed (e.g., mounting, electrical wiring, plumbing, air supply, pneumatic and/or hydraulic lines, etc.). However to get the device to be reconfigured to function in the same way in the system is often troublesome. Once the device is hooked up, conventional systems require a connection to the device in order to configure the device. Typically, an original configuration software tool is required as well as the current device configuration file. Often, there are difficulties in that the configuration will not be available, or will be outdated. Moreover, the maintenance personnel might actually have the proper configuration, but because there could be many instances of configuration software from many different vendors, the maintenance personnel may be unable to locate it in order to download it to the device.
These same difficulties exist not only with the configuration information, but also with the control information. For example, when it is time to configure, re-configure, troubleshoot and/or monitor the device, the DTM may not be available to the software tool. For example, the compact disc (CD) may have been lost before it was installed, or there was a firmware upgrade done to the device in the field and there is a newer version of the DTM needed, but access to the Internet is not available at that time for uploading it from the Vendor's website.
Additionally, other difficulties exist as well. For instance, a user may utilize a software programming tool to "tweak" the functionality of a device, yet these modifications do not show up in the controller and/or the controller programs, and therefore could cause undesirable consequences because the device is now functioning in a manner in which the controller is not aware. Moreover, when a Connection Originator (CO) (e.g., a controller) desires to establish a Common Industrial Protocol (CIP) I/O connection with a device, the CO issues an open connection request in accordance with the CIP Specification. Among other things, this request includes a data segment, which contains the configuration parameters for the device.
The inclusion of the device configuration data with the connection request insures that the device is setup to perform its function(s) in accordance with the needs of the CO and that the data to be exchanged will be meaningful (e.g. desired data type, properly scaled, etc.) to the CO. It also serves the added benefit of insuring that if the device is replaced, that it will be configured exactly the same as the original device. However, the data segment is limited to a theoretical max of 510 bytes. But in practice, due to limitations of network message size combined with other data in the open connection request, it is generally limited to about 450 bytes. While this was adequate for the great majority of devices in prior years, more recently devices with configuration larger than 450 bytes have become more common.

This patent is subject to a terminal disclaimer.

Embedding controllers and devices with data to facilitate up-to-date control and configuration information


A backsplash includes a faucet that provides point-of-use dispensing of water to a cooktop container. The backsplash includes controls that allow a user to select a desired amount of water to be dispensed, as well as the temperature of water to be dispensed. A filter assembly includes a replaceable filter that allows for filtered water dispensation. Optionally, the backsplash can be connected to one or more appliances in the kitchen in order to communicate information and/or power. The backsplash may also include a ventilation channel to direct vented air from a range to a ventilation shaft.

1. Field of the Invention
The present invention pertains to the art of cooking and, more particularly, to a water dispensing backsplash for a cooktop.
2. Description of the Related Art
Typically, consumers must fill cooking pots with water from a faucet at a kitchen sink before transporting the filled pots to a cooktop for heating. Transporting heavy water filled pots to the cooktop can be problematic. Additionally, when recipes call for precise amounts of water, a consumer must measure out water from the faucet before adding the water to the cooking pot and transporting the pot to the cooktop.
In general, it is known in the art to provide a faucet and drain system adjacent a wok range in order to provide water for cooling woks during cooking, as demonstrated by U.S. Patent Application Publication No. 2005/0235981. However, this system is intended for use in a restaurant environment, and does not address the needs of a domestic cook. Therefore, there is seen to be a need for a system and method for supplying measured amounts of water to a cooking container on a cooktop.


A dual edge pulse width modulation system includes a ramp generator for generating a voltage ramp; an n bit digital to analog converter having a normal and an inverted output for establishing a leading edge and a trailing edge reference; a comparator responsive to the ramp and the leading edge and trailing edge references, respectively, for defining the leading edge and the trailing edge of a pulse; and a pulse generator for producing a pulse having the width determined by the defined leading and trailing edges.

There are three types of pulse width modulation: leading edge modulation (LEM), trailing edge modulation (TEM), and dual edge modulation (DEM). Typically LEM can be produced with one ramp, two comparators and a reference voltage which fixes the trailing edge of the pulse. TEM is accomplished by a similar arrangement but the reference voltage is at the beginning of the ramp to fix the leading edge of the pulse. These circuits produce but one pulse during every other clock cycle. As the ramp recovers, half of the clock cycle is unusable. In high speed applications two such circuits are used to provide a ramp during each half clock cycle so a sequence of alternate pulses is provided. To generate DEM, two ramps and two reference voltages are used, and in high-speed applications, again, two such circuits are used to obtain a sequence of alternating pulses. In another approach a phase locked loop (PLL) is employed with a triangular (dual ramp) waveform to obtain center justified DEM. While this approach does eliminate some of the redundancy of the prior arrangements it introduces the extra expense and complexity associated with PLLs. In addition, PLLs do not lend themselves to easy transition between formats LEM, TEM, DEM. The output of the PLL at lock may not line up exactly with other formats and so an offset adjust must be added. These offset adjusts are not always well controlled and need to be compensated.


Aspects of the disclosure provide a voltage controlled oscillator. The voltage controlled oscillator can include a plurality of oscillation stages coupled together to generate an oscillation signal having an oscillation frequency. At least one oscillation stage of the plurality of oscillation stages can include a first portion driven by a first driving power that can be a function of a control voltage and a second portion driven by a second driving power that can be substantially independent of the control voltage. The first driving power can be provided by a first power rail in the form of a driving current that is a function of the control voltage. The second driving power can be provided by a second power rail in the form of a substantially constant voltage that is substantially independent of the control voltage.

Oscillators can be used in integrated circuits for various purposes. For example, a voltage controlled oscillator can be associated with a phase-locked loop (PLL) module to generate an internal clock signal having its phase locked to a received signal. The PLL module may include a phase detector coupled to the voltage controlled oscillator. The phase detector may detect a phase difference of the internal clock signal and the received signal. The phase difference can be converted to a voltage signal. The voltage signal can be used to vary an oscillation frequency of the voltage controlled oscillator, such that the phase of the internal clock signal can be locked to the received signal.


A tensioner system for a top-tensioned riser in a floating platform includes a hydro-pneumatic tensioner assembly resiliently mounted to the floating platform, and a riser support conductor surrounding the riser coaxially, wherein the support conductor conveys a pull-type tensional force from the hydro-pneumatic tensioner assembly to the riser through a riser conductor coupling assembly that engages the tensioner assembly and the riser support conductor to convey the tensional force. A riser tension joint support assembly conveys the tensional force from the riser support conductor to a riser tension joint on the riser. The tensioner assembly compensates for relative platform motion including pitch, heave, and yaw. Also a reactive load assembly is mounted to the platform and reacts to a two-point dynamic bending moment imposed on the riser support conductor, while resisting riser support conductor rotation.

This invention relates generally to the field of floating offshore platforms or vessels for the exploitation of undersea deposits of petroleum and natural gas. More specifically, it relates to a system and apparatus for tensioning risers that extend from a subsea wellhead or subsurface structure to a floating platform or vessel.
Offshore platforms for the exploitation of undersea petroleum and natural gas deposits typically support production risers that extend to the platform from one or more wellheads or structures on the seabed. In deep water applications floating platforms (such as spars, tension leg platforms, extended draft platforms, and semi-submersible platforms) are typically used. These platforms are subject to motion due to wind, waves, and currents. Consequently, the risers employed with such platforms must be tensioned so as to permit the platform to move relative to the risers. Also, riser tension must be maintained so that the riser does not buckle under its own weight. Accordingly, the tensioning mechanism must exert a substantially continuous tension force to the riser within a well-defined range.
One broad class of risers is the category called "Top Tensioned Risers" or TTRs. Such risers extend from the subsea wellheads below the hull of the platform substantially vertically to the deck area of the platform, where they are supported by a tensioning mechanism; hence the term "Top Tensioned Riser." Each TTR typically extends from a riser tension point up into the production deck levels of the platform with the use of a heavy wall conduit or stem joint. At the top of the conduit or stem joint is an upper riser termination where a surface wellhead and a production tree or flow control device are mounted. (Platforms with such an arrangement are called "dry tree" platforms.) A flexible jumper attached to the production tree enables the produced well fluids to be transferred to the topside processing facilities.
Passive buoyancy cans are a well-known type of riser tensioning mechanism that is used primarily on spars. The buoyancy cans independently support each TTR, which allows the platform to move up and down relative to the riser. This isolates the risers from the heave motion of the platform and eliminates any increased riser tension caused by the horizontal offset of the platform in response to the marine environment.
Hydro-pneumatic tensioner systems are another form of riser tensioning mechanism used to support TTRs on various dry tree platforms. Hydro-pneumatic riser tensioning has its origins in the support of drilling risers of MODUs (mobile offshore drilling units). A plurality of active hydraulic cylinders with pneumatic accumulators is connected between the platform and the riser to provide and maintain the necessary riser tension. Platform responses to environmental conditions, mainly heave and horizontal motions causing hull set-down, necessitate changes in riser length relative to the platform, which causes the tensioning cylinders to stroke in and out. The spring effect caused by the gas compression or expansion during riser stroke partially isolates the riser from the low heave platform motions while maintaining a nearly constant riser tension. However, when the platform takes a significant horizontal offset, the compression of the gas in the cylinders causes increased cylinder pressure and thus increased riser tension. The magnitude of this increased riser tension is a function of the stiffness of the riser and the tensioning system.
Two major types of hydro-pneumatic tensioner systems are currently in use: the "push" or compression style system and the "pull" or tension style system. Both systems use hydraulic cylinders having pistons with piston rods connected to the riser by a tension ring device. Push-style cylinders are mounted with the piston rods looking up, and they use pressure applied to the piston side of the cylinders to provide riser tension. The piston rods effectively push up on the riser, putting the rods in compression while providing the necessary riser tension. The pull-style cylinders, by contrast, are mounted with the piston rods looking down. Pressure applied to the rod side of the cylinders puts the piston rods in tension while pulling up on the riser to generate the riser tension.
Pull-style tensioner systems have to date been used predominately on tension leg platforms (TLPs) to support TTRs. The tensioner cylinders may be symmetrically mounted under the well deck, outboard of the riser, using padeyes and shackles, or they can be mounted in a similar manner in a cassette frame that is then mounted to the well deck. The cylinders are angled inboard to riser attachment points on a tension ring. Generally, a roller assembly mounted at the well deck level above the tension ring is used to provide lateral support to the riser as it passes through the tensioner.
The pull-style tensioners on TLPs are designed for short strokes due to the low heave characteristics of the hull, combined with the relatively small riser length changes associated with small hull set down due to the parallelogram arrangement formed by the platform, tendons, risers, and the seafloor well pattern. The advantage is that the surface production tree or flow control device at the top of the riser on a TLP can be mounted closer to the tensioning point of the riser, and the well spacing inside the platform can be reduced. This reduces the bending loads induced in the portion of the riser above the tension point, i.e., the upper riser stem joint, from the dynamic motions of the surface production equipment. However, the production equipment for other hull types and riser system configurations may be located some distance away from the tensioning point. Because there is generally only one set of lateral motion restraining devices (such as rollers) to restrain the riser laterally, dynamic bending moments from the production equipment are transferred across the rollers and the tension ring into the riser pipe below the tension point. Also, riser vortex induced vibration (VIV) oscillations can be transferred across the tension ring and into the upper riser stem joint, possibly affecting its fatigue life.
If a tension cylinder failure occurs, the eccentric load generated by the unequal application of cylinder forces at the tension ring may also cause additional bending moments that must be reacted to by the riser pipe. The unbalanced cylinder forces can also cause the riser and the surface tree to lean to one side. The occurrence of dynamic bending moments from the production equipment and the failed cylinder scenario dictate that the tensioning cylinders be mounted so as to allow pivoting, such as with the use of padeyes and shackles. Pivot mounting eliminates the need for the cylinders and cylinder supports to react to the various loads. However, because the cylinders are generally hung from above to pull up and are also angled inboard to the riser, failed cylinder change-out is made more difficult because of the location of the cylinders below the hang-off deck.
Push-style tensioner systems are a more recent approach to riser tensioning and have been used on deepwater spars to support TTRs and drilling risers. Typically, four to six push-style cylinders are vertically mounted to the platform deck. A piston is journaled in each of the cylinders, each of the pistons being connected to an upwardly-extending piston rod that is attached to a structural top frame. The structural top frame, in turn, supports a large diameter conductor pipe and contains the tension ring attachment to the riser. The piston rods push up on the top frame, which, in turn, pushes up on the riser via a tension ring. The conductor pipe, with two sets of reaction rollers, creates a two-point force coupling to react to riser dynamic bending moments generated from the production equipment and failed cylinder-induced bending moments. The conductor pipe and the associated anti-rotation devices also resist riser torque induced by platform or vessel yaw motions. Because the rods are in compression and are required to resist buckling under very large loads, the rod diameters are larger than those of a pull-style tensioner system.
In general, while conventional pull-style tensioners, as described above, are generally smaller, less expensive, and more widely available than push-style tensioners, the typical pull-style tensioner system generally exhibits one or more of the following disadvantages: (1) It may not provide two-point reaction to riser dynamic bending moments generated by surface production equipment located above the riser tension point. (2) The lack of two-point reaction also allows riser VIV oscillations below the tension point to excite the surface equipment above the tension point, thus adversely affecting its fatigue life. (3) It may not react adequately to failed cylinder eccentric loads, thus creating additional riser bending moments. (4) It may not sufficiently resist riser rotation (torque) created by platform yaw motions. (5) Failed cylinder replacement is made more difficult by below-deck work requirements.

Pull-style tensioner system for a top-tensioned riser


A family of improved paper clips and a process for their formation is disclosed which comprises a central bridge leg joining two overlapping and contacting gripping jaws. Each gripping jaw lies in its own plane and controlled torsional forces in the legs comprising the jaws provide for independently controlled gripping forces at multiple tangential contact points. The controlled gripping forces and two layer planar shape result from a substantially elastic transformation from a preceding stepped helix wire form. The advantages include a firm grip on thin or thick packets, the ability to stay flat on thick packets of material, resistance to distortion, special features to aide application to thin or thick packets of material, and modest size facilitating its general purpose use.

1. Field of Invention
This invention relates to paper clips which are removable, and preferably reusable, means of holding together collections of papers or other materials as well as serving as place markers in a book and/or locations on a page.
2. Prior Art
The most common paper clip, known as a Gem style configuration, originated about 1900. Its deficiencies include not lying flat when used with even modestly thick packets, unsuitability for use with thick packets, somewhat difficult to apply, weak gripping force with thin packets, tendency to dimple materials when left in place for any significant time, easily distorted, cut ends that can dig into and damage the surface sheets, etc.
These deficiencies, particularly ease of application and suitability for thick documents, have been addressed by other paper clip patents and product designs over the years. None however have offered sufficiently significant advantages to displace the Gem style as the dominant general purpose product design and only a relative few survive as niche products.
Comments on the products and patents most relevant to the instant invention follow:
Universal, Imperial and Ezeon style paper clips appear to derive from U.S. Pat. No. 1,344,473 Baldwin (1920). They consist of a relatively short, straight, central bridge leg connected to two near parallel and perpendicular side legs. Ending legs attached at the bottom of the side legs angle off at less than 45 degrees to the side legs and make one or more tangential contacts with the opposing side leg. Their central funnel mouth makes them easy to attach but as a group they have only a modest grip, easily distort and do not lie flat when used with thicker documents.
Ideal style paper clips are generally built in larger sizes and involve a relatively long, straight, central bridge leg connected to two crossing, diagonally angled side legs. The lower ends of these diagonal legs are coupled to two ending legs which Consist of a short vertical segment and a longer angled segment which crosses, but does not contact, its opposite member. Its forte is easy application to, and relatively good ability to lie flat with, thick packets. It also eliminates the risk of paper dimpling over time. However it is not suitable for general purpose use with only a few sheets due to its large size, limited gripping strength, and tendency to grip and pivot about only a single one of its crossing leg paths. Additionally the lower angled corners of the clip protrude substantially beyond the boundary of the opposing gripping jaw due to the crossing point of the the two side legs being approximately at the midpoint of the side legs. These protruding corners easily lift out of contact and can snag other pages.
U.S. Pat. No. 4,949,435 by Michelson (1990) has an objective of providing a paper clip that can stay flat when used with large packets of materials. However it has only limited gripping force for both thin and thick packets, its single pinch point and limited gripping footprint allows the clip to be easily dislodged, the clip and/or material being gripped pivots too easily, the ability to stay flat is limited and it has a similar excessive projection limitation as with the Ideal style.
U.S. Pat. No. 3,083,425 by Minnerly (1963) describes a clip geometry that is intended for gripping thick packets and provides for means to achieve a preloaded gripping action. However the design does not provide for sufficient elasticity between its gripping jaws, would not lie flat in its ready to use state and proposes a difficult to accomplish and control final folding action.

Firmly gripping high capacity paper clip


The present invention is a mid-pipeline sorting unit that sorts image data mid-pipeline in a tiled 3-D graphics pipeline architecture. The image data includes vertices of geometric primitives. The mid-pipeline sorting determines whether a geometric primitive intersects a region of a 2-D window. The 2-D window having been divided into multiple such regions. Upon determining which region of the 2-D window that the geometric primitive intersects, the mid-pipeline sorting unit stores the vertices that define the geometric primitive into a memory in a manner that associates each of the geometric primitive""s vertices with the region that was intersected. After the image data is sorted into the memory, the mid pipeline sorting unit sends the sorted image data to the subsequent stage on a region by region basis.

The present invention relates generally to a computer structure and method for processing three-dimensional (xe2x80x9c3-Dxe2x80x9d) computer graphics in a 3-D graphics processor. More particularly, the present invention is directed to a computer structure and method for spatially sorting image data with respect to regions of a 2-D window that is divided into multiple equally sized regions, wherein the image data is comprised of geometric primitives and/or mode information. Yet another embodiment of the present invention, provides an indication of whether enough free space is available in a memory to sort and store image data into the memory. Yet another embodiment of the present invention, balances the effects that horizon complexity and scene complexity can have on subsequent stages of a graphics pipeline by sending image data to a next stage in the pipeline in a spatially staggered sequence.
The art and science of three-dimensional (xe2x80x9c3-Dxe2x80x9d) computer graphics concerns the generation, or rendering, of two-dimensional (xe2x80x9c2-Dxe2x80x9d) images of 3-D objects for display or presentation onto a display device or monitor, such as a Cathode Ray Tube or a Liquid Crystal Display. The object may be a geometric primitive (hereinafter also referred to simply as a xe2x80x9cprimitivexe2x80x9d) such as a point, a line segment, or a polygon. More complex objects can be rendered onto a display device by representing the objects with a series of connected planar polygons, such as, for example, by representing the objects as a series of connected planar triangles. All geometry primitives may eventually be described in terms of one vertex or a set of vertices, for example, coordinate (x, y, z) that defines a point, for example, the endpoint of a line segment, or a corner of a polygon.
To generate a data set for display as a 2-D projection representative of a 3-D primitive onto a computer monitor or other display device, the vertices of the primitive must be processed through a series of operations, or processing stages in a graphics rendering pipeline. A generic pipeline is merely a series of cascading processing units, or stages wherein the output from a prior stage, serves as the input for a subsequent stage. In the context of a graphics processor, these stages include, for example, per-vertex operations, primitive assembly operations, pixel operations, texture assembly operations, rasterization operations, and fragment operations.
The details of the various processing stages, except where otherwise noted, are not necessary to practice the present invention, and for that reason, will not be discussed in greater detail. A summary of the common processing stages in a conventional rendering pipeline can be found in the following standard reference: xe2x80x9cFundamentals of Three-dimensional Computer Graphicsxe2x80x9d, by Watt, Chapter 5: The Rendering Process, pages 97 to 113, published by Addison-Wesley Publishing Company, Reading, Mass., 1989, reprinted 1991, ISBN 0-201-15442-0, which is hereby incorporated by reference for background purposes only. Very few conventional graphics pipelines have tiled architectures. A tiled architecture is a graphic pipeline architecture that associates image data, and in particular geometry primitives, with regions in a 2-D window, where the 2-D window is divided into multiple equally size regions. Tiled architectures are beneficial because they allow a graphics pipeline to efficiently operate on smaller amounts of image data. In other words, a tiled graphics pipeline architecture presents an opportunity to utilize specialized, higher performance graphics hardware into the graphic pipeline.
Those graphics pipelines that do have tiled architectures do not perform mid-pipeline sorting of the image data with respect to the regions of the 2-D window. Conventional graphics pipelines typically sort image data either, in software at the beginning of a graphics pipelines, before any image data transformations have taken place, or in hardware the very end of the graphics pipeline, after rendering the image into a 2-D grid of pixels.
Significant problems are presented by sorting image data at the very beginning of the graphics pipelines. For example, sorting image data at the very beginning of the graphics pipelines, typically involves dividing intersecting primitives into smaller primitives where the primitives intersect, and thereby, creating more vertices. It is necessary for each of these vertices to be transformed into an appropriate coordinate space. Typically this is done by subsequent stage of the graphics pipeline.
Vertex transformation is computationally intensive. Because none of these vertices have yet been transformed into an appropriate coordinate space, each of these vertices will need to be transformed by a subsequent vertex transformation stage of the graphics pipeline into the appropriate coordinates space. Coordinate spaces are known. As noted above, vertex transformation is computationally intensive. Increasing the number of vertices by subdividing primitives before transformation, slows down the already slow vertex transformation process.
Significant problems are also presented by spatially sorting image data at the end of a graphics pipeline (in hardware). For example, sorting image data at the end of a graphic pipeline typically slows image processing down, because such an implementation typically xe2x80x9ctexture mapsxe2x80x9d and rasterizes image data that will never be displayed. To illustrate this, consider the following example, where a first piece of geometry is spatially located behind a second piece of opaque geometry. In this illustration, the first piece of geometry will never be displayed.
Another problem with spatially sorting image data at the end of the graphics pipeline is that such an implementation typically requires a larger data cache and/or more RAM to store the spatially sorted image data, because the texture mapped and rasterized image data needs to be stored before it is displayed, even if certain image data will not be seen. Therefore, what is needed is a structure and method for a spatially sorting image data that does not have the larger data cache and/or RAM footprints as required in existing art. To achieve this goal, such an implementation must efficiently manage finite cache and memory by not texture mapping and rasterizing those image data that will not be displayed. Ideally, it is desirable to sort image data mid-pipeline, after image data coordinate transformations have taken place, and before the image data has been texture mapped and/or rasterized, it is also desirable to remove hidden pixels from the image data before the image data has been texture mapped and/or rasterized. Therefore, what is needed is a tiled graphics pipeline architecture that performs not only, mid-pipeline sorting, but mid-pipeline culling.
We will now discuss conventional graphics pipeline rendering resource balancing problems. Image data is typically sent from one stage of a graphics pipeline to another stage of the graphics pipeline in a row-by-row, or column-by-column manner, utilizing a first-in/first-out (xe2x80x9cFIFOxe2x80x9d) strategy. Significant problems are presented by outputting image data to a next stage of a graphic pipeline in such a manner. For example, outputting image data on a FIFO basis does not take into account how scene complexity and/or horizon complexity across different portions of an image may place differing loads on subsequent stages of the graphics pipeline, and possibly result in less efficient pipeline processing. Scene complexity is the number of primitives in a portion of an image. Horizon complexity is the variation in the density of primitives near a horizon in the image.
To illustrate this problem, consider that an image (or a portion of an image) that has a low complexity (scene complexity or horizon complexity) requires a lesser amount of data to represent it, as compared to the greater amount of data required to represent an image (or portion of an image) that has a high complexity. If one stage of the graphics pipeline sends data representing an image having high complexity (a complexity that varies significantly over different parts of the image) on a FIFO basis to subsequent stages of the pipeline, the processing loads often will not be balanced across the different stages, resulting in a less efficient graphics pipeline.
An ideal graphics pipeline implies that data is distributed across various graphics pipeline stages in a balanced manner, such that the rendering resources of the graphics pipeline are efficiently utilized.
Many of today""s 3-D graphics applications run on computers having interactive graphical user interface that include window managers. Such graphical user interfaces include, for example, Microsoft Widows 3.1, Windows 95, and Windows 98. While using such an graphics application, a user may occlude one or more portions of the 2-D window by dragging and dropping a second window across a first window that is to be rendered. It is desireable in such situations, to send only those image data that represent the visible portions of the first window down stages of a graphics pipeline, while discarding those image data, or fictional image data that do not contribute to the visible portions of the first window. 3-D graphics pipelines typically do not cull such fictional image data until the very end of a rendering pipeline. Ideally, fictional image data would be culled before the end of the rendering pipeline, such that rendering pipeline resources, for example, memory and image processing cycles, would not be utilized in managing such fictional data.
In light of the above, there exists a need to overcome each of the above discussed limitations in the existing art which is satisfied by the inventive structures and methods described hereinafter. In particular, there is a need for: (1) a structure and method for spatially sorting primitives after they have been transformed into a common coordinate system, such that an image processors bandwidth is not increased and the amount of transformations required to be performed on the image data is not increased; (2) a computer structure and method providing efficient memory management of finite memory resources in a sorting stage of a 3-D graphics pipeline, such that memory overflows are prevented before they occur; (3) a structure and method for balancing rendering process resources in a 3-D graphics pipeline; and, (4) a graphics pipeline that sends only those image data that represent the visible portions of a window down stages of a graphics pipeline, while discarding those image data that are hidden that do not contribute to the visible portions of the window.
In summary, the present invention is a mid-pipeline sorting unit that sorts image data mid-pipeline in a tiled 3-D graphics pipeline architecture. The image data includes vertices of geometric primitives. The mid-pipeline sorting unit is operatively coupled to a previous processing stage of the graphics pipeline and a subsequent processing stage of the graphics pipeline. The mid pipeline sorting unit reads the image data from the previous processing stage. The mid-pipeline sorting determines whether a geometric primitive intersects a region of a 2-D window. The 2-D window having been divided into multiple such regions. Upon determining which region of the 2-D window that the geometric primitive intersects, the mid-pipeline sorting unit stores the vertices that define the geometric primitive into a memory in a manner that associates each of the geometric primitive""s vertices with the region that was intersected. After the image data is sorted into the memory, the mid pipeline sorting unit sends the sorted image data to the subsequent stage on a region by region basis.
In yet another embodiment of the present invention, the mid pipeline sorting unit includes a guaranteed conservative memory estimates circuit for determining whether there is enough free memory in the memory for the mid-pipeline sorting unit to sort the image data into the memory. The guaranteed conservative memory estimate circuit returns its determination of whether there is enough free memory for the mid pipeline sorting unit to sort and store the image data.
Yet another body of the present invention, the mid pipeline sorting unit sends image data that has been sorted with respect to a set of regions of a 2-D window to the subsequent stage of the graphics pipeline in a spatially staggered sequence.

System, apparatus and method for spatially sorting image data in a three-dimensional graphics pipeline

Abstract: Yet another embodiment of the present invention provides a guaranteed conservative memory estimate to the mid-pipeline sorting stage of whether there is enough free memory for the mid pipeline sorting unit to sort and store the image data.

Abstract: Yet another embodiment of the present invention sends image data from a memory to a next stage in a graphics pipeline in a spatially staggered sequence.


A multiplex driving method is provided for a liquid crystal cell device having a liquid crystal layer disposed between a pair of substrates, a plurality of row electrodes arranged on one of the substrates and a plurality of column electrodes arranged on the other substrate. The method comprises the steps of sequentially selecting a group of the plurality of row electrodes during a selection period, simultaneously selecting the row electrodes comprising the group, and dividing and separating the selection period into a plurality of intervals within one frame period.

Matrix liquid crystal displays such as, twisted nematic (TN) and super twisted nematic (STN), are known in the art. Reference is made to FIGS. 21(a)-(e) and 22 in which a conventional matrix liquid crystal display is provided. A liquid crystal panel generally indicated as 1 is composed of a liquid crystal layer 5, a first substrate 2 and a second substrate 3 for sandwiching the liquid crystal layer 5 therebetween. A group of column electrodes Y.sub.1 -Y.sub.m are oriented on substrate 2 in the vertical direction and a plurality of row electrodes X.sub.1 -X.sub.n are formed on substrate 3 in substantially the horizontal direction to form a matrix. Each intersection of column electrodes Y.sub.1 -Y.sub.m and row electrodes X.sub.1 -X.sub.n forms a display element or pixel 7. Display pixels 7 having the open circle indicate an ON state and those pixels having a blank indicate an OFF state.
A conventional multiplex driving based on the amplitude selective addressing scheme is known to one of ordinary skill in the art as one method of driving the liquid crystal cells mentioned above. In such a method, a selected voltage or non-selected voltage is sequentially applied to each of row electrodes X.sub.1 -X.sub.n individually. That is, a selection voltage is applied to only one row electrode at a time. In the conventional driving method, the time period required to apply the successive selected or non-selected voltage to all the row electrodes X.sub.1 -X.sub.n is known as one frame period, indicated in FIGS. 21(a)-(e) as time period F. Typically the frame period is approximate 1/60th of a second or 16.66 milliseconds.
Simultaneously to the successive application of the selected voltage or the non-selected voltage to each of the row electrodes X.sub.1 -X.sub.n, a data signal representing an ON or OFF voltage is applied to column electrodes Y.sub.1 -Y.sub.m. Accordingly, to turn a pixel 7 e.g, the area in which the row electrode intersects the column electrode, to the ON state, an ON voltage is applied to a desired column electrode when the row electrode is selected.
Referring specifically to FIGS. 21(a)-(e), a conventional multiplex drive method of a simple matrix type liquid crystal and more specifically the amplitude selective addressing scheme are shown therein. FIGS. 21(a)-(c) show the row selection voltage waveforms that is applied in sequence to row electrodes X.sub.1, X.sub.2 . . . X.sub.n, respectively. More particularly, in time period t.sub.1, a voltage pulse having a magnitude of V.sub.1 is applied to row electrode X.sub.1, and a voltage of zero is applied to electrodes X.sub.2 -X.sub.n ; in time period t.sub.2, a voltage pulse having a magnitude of V.sub.1 is applied to row electrode X.sub.2 and a voltage of zero is applied to electrodes X.sub.1 and X.sub.3 -X.sub.n ; and in time period t.sub.n, V.sub.1 is applied to row electrode X.sub.n and a voltage of zero is to electrodes X.sub.1 -X.sub.n-1. In other words, a voltage pulse having a magnitude of V.sub.1 is applied to only one row electrode X.sub.i in time t.sub.i. Typically, t.sub.i is approximately 69.mu. seconds and V.sub.1 is approximately 25 volts. As will be apparent to one who has read this description, all of the row electrodes are sequentially selected in time periods t.sub.1 -t.sub.n or one frame period F.
FIG. 21(d) shows the waveform applied to column electrode Y.sub.i, and FIG. 21(e) shows the synthesized voltage waveform applied to the pixel 7.sub.1,1 formed at the intersection of the column electrode Y.sub.1 and the row electrode X.sub.1. As shown therein, during time period t.sub.1, a voltage pulse having a magnitude of V.sub.1 is applied to row X.sub.1 and a voltage pulse of -V.sub.2 is applied to column electrode Y.sub.1. Typically, V.sub.2 is approximately 1.6 volts. The resultant voltage at pixel 7.sub.1,1 is -(V.sub.1 -V.sub.2). This synthesized voltage is sufficient to turn pixel 7.sub.1,1 to its ON state.
One known problem with this method is that in order to select and drive the one line of the row electrodes, a relatively high voltage is required to provide good display characteristics, such as, contrast and low distortion. These conventional displays, requiring such a high voltage, also consume relatively more energy. When such displays are used in portable devices, they are supplied with electrical energy by, for example, batteries. As a result of the higher energy consumption, the portable devices have relatively shorter times of operation before the batteries require replacement and/or recharging.
Various attempts have been made to overcome this problem. For example, it has been suggested in "A Generalized Addressing Technique for RMS Responding Matrix LCDs," 1988 International Display Research Conference, pp. 80-85. to simultaneously applying a row selection voltage to more than one row electrode.
As shown in FIGS. 23(a)-(d), a conventional method for driving a liquid crystal display by simultaneously selecting a group of more than one row electrode is shown. As shown therein, the n row electrodes are divided in j groups of row electrodes, each group comprising, for example, two row electrodes. In this example, row electrodes X.sub.1, X.sub.2 ; X.sub.3, X.sub.4 ; and X.sub.n-1, X.sub.n, each form a group of row electrodes.
Referring again to FIG. 23(a), that figure illustrates row selection voltage waveforms applied simultaneously to both row electrodes X.sub.1 and X.sub.2 in time periods t.sub.1 and t.sub.2 and a voltage of zero is applied to row electrodes X.sub.1 and X.sub.2 in the remaining time periods of frame period F. Similarly, FIG. 23(b) indicates the row selection voltage waveforms applied to row electrodes X.sub.3 and X.sub.4, during time periods t.sub.3 and t.sub.4 and a voltage of zero is applied to row electrodes X.sub.3 and X.sub.4 in the other time periods of frame period F. FIG. 23(c) illustrates the voltage waveform applied to column electrode Y.sub.1, and FIG. 23(d) indicates the synthesized voltage waveform applied to the pixel 7.sub.1,1. Generally, t.sub.1, t.sub.2, . . . t.sub.n =69.mu. seconds, V.sub.1 is approximately 17.6 volts and V.sub.2 is approximately 2.3 volts.
As shown in the example of FIGS. 23(a)-(d) every two row electrodes are selected in sequence. In the first selection sequence, two row electrodes, X.sub.1 and X.sub.2, are selected and row selection voltage waveforms such as that shown in FIG. 23(a) are applied to each row electrode. At the same time, the designated column voltage, which is described below, is applied to each column electrode, Y.sub.1 to Y.sub.m. Next, row electrodes X.sub.3 and X.sub.4 are simultaneously selected with substantially the same type of waveform voltages as that described above. At the same time, the column voltages Y.sub.1 to Y.sub.m are applied to each column electrode. One frame period represents the selection of all row electrodes, X.sub.1 to X.sub.n. In other words, a complete image is displayed during one frame.
As will be explained hereinbelow, when h row electrodes are simultaneously selected, the voltage waveforms that apply the row electrodes described above use 2.sup.h row-select patterns. In the example illustrated in FIGS. 23(a)-(d), the number of row electrodes simultaneously selected is two, thus the number of row select patterns is 2.sup.2 or 4.
Moreover, the column voltages applied to each column electrode Y.sub.1 to Y.sub.m provide the same number of pulse patterns as that of the row select pulse patterns. That is, there are 2.sup.h pulse patterns. These pulse patterns are determined by comparing the states of pixels on the simultaneously selected row electrodes i.e., whether the pixels are ON or OFF, with the polarities of the voltage pulses applied to row electrode.
In this example, as shown in the previously described FIGS. 23(a)-(d), when row electrodes X.sub.1 and X.sub.2 are selected and row voltages such as those in FIG. 23(a) and FIG. 24(a) are applied thereto and when the pixels on row electrodes X.sub.1 and X.sub.2 are ON and OFF, respectively, the voltage waveform applied the column electrode is voltage waveform Y.sub.a shown in FIG. 24(b). When the pixels are OFF and ON, respectively, the column voltage waveform Y.sub.b is applied to the column electrode. In another example, when the pixels are both ON, a voltage waveform YC is applied to the column electrode. Finally, when both pixels are OFF, the a column voltage waveform Y.sub.d is applied to the column electrode.
The above-mentioned column voltage waveforms Y.sub.a -Y.sub.d are determined as follows. At first, each pixel simultaneously selected is defined to have a first value of 1 when the voltage applied by the row electrode to the corresponding selected pixel is positive or a first value of -1 when the row electrode is negative. Each of the selected pixels is defined to have a second value of -1 when the display state is ON or a second value of 1 when display state is OFF. The first value is compared to the second value bit-by-bit, the difference between the number of matches, i.e., when the first value equals the second value, and the number of mismatches, i.e., when the first value does not equal the second value, is calculated. When the difference between the number of matches and mismatches for the simultaneously selected rows is two, V.sub.2 is applied; when 0, V.sub.0 is applied; and when -2, -V.sub.2 is applied.
For example, when the pulse waveforms shown in FIG. 23(a) are applied to row electrodes X.sub.1 and X.sub.2, a column voltage having the waveform of Y.sub.a is applied. This column voltage is determined as follows. The pixels formed at the intersections of column electrode Y.sub.1 and rows electrodes X.sub.1 and X.sub.2 are in the ON and OFF states, respectively. For the purposes of this discussion, these pixels will be referred to as the first and second pixels, respectively. In other words, the first pixel has a second value of -1 and the second pixel has a second value of 1. During the period t.sub.a, the first pixel has a first value of -1 and the second pixel has a first value of -1, since the row voltages X.sub.1 and X.sub.2 are both -V.sub.1. Referring to the first pixel, since the first value is -1 and the second value is -1, there is a match. With regard to the second pixel, the first value is -1 and the second value is 1, thereby forming a mismatch. The difference between the number of mismatches and matches is 1--1 or zero. Therefore, a voltage of 0 (zero) is applied to the column electrode in time t.sub.a. Next, concerning the pulse waveforms of the time interval t.sub.b, the applied voltage of row electrode X.sub.1 is positive and the applied voltage of row electrode pulse X.sub.2 is negative. Using a similar analysis as described above, the number of matches is zero and the number of mismatches is 2. Thus, -V.sub.2 volts will be applied to the second half of time interval t.sub.1.
As should now be apparent, the first values in time interval t.sub.c in FIG. 23(a) are -1 and 1 because the applied voltage of row electrode X.sub.1 is negative and the applied voltage of row electrode X.sub.2 is positive. When these are compared with the second values of the first and second pixels of -1 and 1, the number of matches is two and the number of mismatches is zero. The difference between the number of matches and the number of mismatches is 2. Thus, the column voltage of V.sub.2 volts will be applied in time interval t.sub.c.
In time interval t.sub.d, the applied voltage of row electrodes X.sub.1 and X.sub.2 are both positive. Thus, the first values are 1 and 1. When compared to the pixel states of -1 and 1, the number of matches is 1 and the number of mismatches is 1, thus the difference between the number of matches and the number of mismatches is zero. Accordingly, zero volts will be applied to Y.sub.a for the time interval t.sub.d.
A summary of this analysis for time periods t.sub.a, t.sub.b, t.sub.c and t.sub.d, is shown in Table A below:
TABLE A t.sub.a t.sub.b t.sub.c t.sub.d pixel 1 - ON first value -1 1 -1 1 second value -1 -1 -1 -1 match yes no yes no mismatch no yes no yes 2 - OFF first value -1 -1 1 1 second value 1 1 1 1 match no no yes yes mismatch yes yes no no no. of matches 1 0 2 1 no. of mismatches 1 2 0 1 difference 0 -2 2 0 column voltage 0 -V.sub.2 V.sub.2 0
As is readily apparent, the column voltage Y.sub.a corresponds to the column voltage pattern and is applied to the column to place the first pixel in its ON state and the second pixel in its OFF state.
As for the other column voltage waveforms, Y.sub.b to Y.sub.d, the voltages are selected under the same criteria as described above and are summarized in Tables B, C and D hereinbelow:
TABLE B t.sub.a t.sub.b t.sub.c t.sub.d pixel 1 - ON first value -1 1 -1 1 second value 1 1 1 1 match no yes no yes mismatch yes no yes no 2 - OFF first value -1 -1 1 1 second value -1 -1 -1 -1 match yes yes no no mismatch no no yes yes no. of matches 1 2 0 1 no. of mismatches 1 0 2 1 difference 0 -2 2 0 column voltage 0 -V.sub.2 V.sub.2 0 Column Voltage Applied = Y.sub.b
TABLE C t.sub.a t.sub.b t.sub.c t.sub.d pixel 1 - ON first value -1 1 -1 1 second value -1 -1 -1 -1 match yes no yes no mismatch no yes no yes 2 - OFF first value -1 -1 1 1 second value -1 -1 -1 -1 match yes yes no no mismatch no no yes yes no. of matches 2 1 1 0 no. of mismatches 0 1 1 2 difference 2 0 0 -2 column voltage V.sub.2 0 0 -V.sub.2 Column Voltage Applied = Y.sub.c
TABLE D t.sub.a t.sub.b t.sub.c t.sub.d pixel 1 - ON first value -1 1 -1 1 second value 1 1 1 1 match no yes no yes mismatch yes no yes no 2 - OFF first value -1 -1 1 1 second value 1 1 1 1 match no no yes yes mismatch yes yes no no no. of matches 0 1 1 2 no. of mismatches 2 1 1 0 difference -2 0 0 2 column voltage -V.sub.2 0 0 V.sub.2 Column Voltage Applied = Y.sub.d
In the examples above, the first value is 1 when the row-select voltage has a positive polarity or the first value when the row-select voltage has a negative polarity. Additionally, the second value is -1 when the display state of the pixel is ON, or 1 when the display state is OFF. The column voltage waveforms were selected by means of the difference between the number of matches and the number of mismatches. As will be appreciated by one of ordinary skill in the art, the sign conventions may be inverted. Moreover, it also is possible to set the column voltage waveforms with only the number of matches or the number of mismatches, without having to calculate the difference between the number of matches and the number of mismatches as explained below.
FIGS. 25(a)-(d) illustrate another example of the prior art in which a plurality of row electrodes are divided into groups of row electrodes. The groups of row electrodes are selected in sequence and the row electrodes within each group are simultaneously selected. In this example, each group comprises three row electrodes that are simultaneously selected in order to generate a display pattern, as shown in FIG. 26.
In other words, initially three row electrodes, X.sub.1, X.sub.2 and X.sub.3, are selected and row selection voltages such as those shown in FIG. 25(a) are applied to these row electrodes, X.sub.1, X.sub.2 and X.sub.3, respectively. At the same time, the designated column voltages, to be discussed later, are applied to each column electrode Y.sub.1 to Y.sub.m. Next, row electrodes X.sub.4, X.sub.5 and X6, shown in FIG. 26, are selected and row selection voltages such as that in FIG. 25(b) are applied to these electrodes in the same manner as described above. At the same time, column voltages are applied to each column electrode, Y.sub.1 to Y.sub.m. As with the previous example, one frame period F is defined as the selection of all of the row electrodes, X1 to X.sub.n. One image is completely displayed in one frame period, and plural images can be display by repeating this cycle continuously.
When each row voltage waveform described above has h as the number of row electrodes that are simultaneously selected, as in previous example, the number of 2.sup.h row-select pattern are used. In this example, the number of 2.sup.3 or 8 patterns are used.
Moreover, as in the previous example, the column voltages applied to each column electrode, Y.sub.1 to Y.sub.m, are the same as the number of row-select patterns. Also, the voltage level of each pulse is such that the voltage that corresponds to the numbers of the ON state and the OFF state of the selected row electrodes is applied. In other words, the column voltage level is determined by comparing the row-select pattern and display pattern. Thus, for example, when the row voltage waveforms applied to row electrodes X.sub.1, X.sub.2 and X.sub.3, which are selected simultaneously in this example, have a positive pulse, they are ON, and when they have a negative pulse, they are OFF. The ON and the OFF of the display data are compared at each pulse and the column voltage waveforms are set according to the number of mismatches.
In other words, in the example of FIG. 25(a)-(d), when the number of mismatches is zero, -V.sub.3 volts are applied; when it is 1, -V.sub.2 volts are applied; when it is 2, V.sub.2 volts are applied; and when it is 3, V.sub.3 volts are applied. The voltage ratios for V.sub.2 and V.sub.3 above are preferably such that V.sub.2 :V.sub.3 =1:3
In specific terms, in the case of the voltage waveforms applied to row electrodes X.sub.1, X.sub.2 and X.sub.3 in FIG. 25(a), those waveforms are ON when the V.sub.1 volts are applied and OFF when the -V.sub.1 volts are applied. Referring to FIG. 26, the pixel is indicated as ON when there is a closed circle and OFF when there is a open circle. As shown in FIG. 26, the display states of the pixels that cross with column electrode Y.sub.1 and row electrodes X.sub.1, X.sub.2 and X.sub.3, are ON, ON and OFF, respectively. In contrast to this, the initial pulse pattern of the voltage applied to each row electrode, X.sub.1, X.sub.2 and X.sub.3, is OFF, OFF and OFF, respectively. Comparing both in sequence, the number of mismatches is 2. Therefore, V.sub.2 volts are applied to the initial pulse pattern of the voltage applied to each row electrode Y.sub.1, as shown in FIG. 25(c). Using a similar analysis, the second pulse pattern of the voltage that is applied to each row electrode, X.sub.1, X.sub.2 and X.sub.3, is OFF, OFF and ON, respectively. When compared in sequence the voltage pattern with the ON, ON and OFF sequence of the aforesaid pixel display pattern, all are mismatching. Since the number of mismatches is 3, voltage V.sub.3 is applied to the second pulse of column electrode Y.sub.1. As will be understood by one of ordinary skill in the art, by applying the above described analysis to the third and fourth time intervals, column voltages -V.sub.2 and -V.sub.2 are applied therein. Thus, a column voltage of -V.sub.3, V.sub.2, -V.sub.2 and -V.sub.2 is applied to provide the pixel states as shown in FIG. 26.
In the next time period, the next three row electrodes X.sub.4 to X.sub.6, are selected by applying selection voltages thereto, as shown in FIG. 25(b). In accordance with the analysis described above, column voltages have the voltage levels that corresponds to the number of mismatches between the ON and OFF display states of the pixels formed at the intersection of the row electrodes X.sub.4 to X.sub.6 and the column electrode, and the ON and OFF states of pulse patterns of the synthesized voltages. FIG. 25(d) illustrates the resultant voltage waveforms that are applied to the pixels at the intersection of the row electrode X.sub.1 and column electrode Y.sub.1. That is, the synthesized waveform is resultant of the voltage waveform applied to row electrode X.sub.1 and the voltage waveform applied to column electrode Y.sub.1.
As indicated above, the method that simultaneously selects a plurality of row electrodes in a group and the selection of each group in sequence, has the advantage of the reducing the drive voltage level.
Referring now to FIG. 27, the relationship between the transmissitivity of a pixel of a liquid crystal display and the applied voltage is shown therein. In a liquid crystal display driven in a conventional manner, after the selection voltage has been applied to a particular pixel, during the period until the next selection voltage is applied to that pixel, the brightness gradually decreases during the time t. This reduces the transmissitivity T in the ON condition and, on the other hand, slightly increase the transmissitivity T in the OFF condition. As shown in FIG. 21, such conventional displays have poor contrast between the ON condition and the OFF condition.
The following is a general discussion regarding the conventional method for simultaneously selecting multiple row electrodes.
A. Requirements PA0 B. Guidelines PA0 C. Analysis
(a) The N number of row electrodes to be displayed are divided up into N/h non-intersecting subgroups. PA1 (b) Each subgroup has h number of address lines. PA1 (c) At a particular time, the display data on each column electrode is composed of an h-bit words, e.g.: EQU d.sub.k*h+1, d.sub.k*h+2 . . . d.sub.k*h+h ; d.sub.k*h+j =0 or 1 PA1 d.sub.1, d.sub.2 . . . d.sub.h . . . Subgroup 0 PA1 d.sub.h+1, d.sub.h+2 . . . d.sub.h+h . . . Subgroup 1 PA1 d.sub.N-h+1, d.sub.N-h+2 . . . d.sub.N-h+h . . . Subgroup N/h-1 PA1 (d) The row-select pattern has 2.sup.h cycle and is represented by an h-bit words, e.g.: EQU a.sub.k*h+1, a.sub.k*h+2 . . . a.sub.k*h+h ; a.sub.k*h+j =0 or 1 PA1 (1) One subgroup is selected simultaneously for addressing. PA1 (2) One h-bit word is selected as the row-select pattern. PA1 (3) The row-select voltages are: PA1 (4) The row-select patterns and the display data patterns in the selected subgroup are compared bit by bit such as with digital comparators, viz. exclusive OR logic gates. PA1 (5) The number of mismatches i between these two patterns is determined by counting the number of exclusive-OR logic gates having a logical 1 output. PA1 (6) The column voltage is chosen to be V(i) when the number of mismatches is i. PA1 (7) The column voltages for each column in the matrix is determined independently by repeating the steps (4)-(6). PA1 (8) Both the row voltage and column voltage are applied simultaneously to the matrix display for a time duration .DELTA.t, where .DELTA.t is minimum pulse width. PA1 (9) A new row-select pattern is chosen and the column voltages are determined using steps (4)-(6). The new row and column voltages are applied to the display for an equal duration of time at the end of .DELTA.t. PA1 (10) A frame or cycle is completed when all of the subgroups (=N/h) are selected with all the 2.sup.h row-select patterns once. EQU 1 cycle=.DELTA.t.multidot.2.sup.h.multidot.N/h PA1 V.sub.r /V.sub.0 =N.sup.1/2 /h . . . row selection voltage PA1 V(i)/V0=(h-2i)/h={1-(2i/h)} . . . column voltage, and PA1 R=(V.sub.on /V.sub.off)max={(N.sup.1/2 +1)/(N.sup.1/2 -1)}.sup.1/2
Where 0.ltoreq.k.ltoreq.(N/h)-1 (k: subgroup)
In other words, one column of display data is:
-V.sub.r for a logic 0, PA2 +V.sub.r for a logic 1, PA2 0 volts or ground for the non selected period.
Steps 1-4 are summarized by the following equation: ##EQU1##
(where .sym. is an exclusive OR logic operation)
The row select patterns in a case in which there are i number of mismatches will now be considered. The number of h-bit row-select patterns which differ from and h-bit display data pattern by i bits is given by EQU hCi=h!/{i! (h-i)!}=Ci
For example, when the case for h=3 and row electrode selection pattern =(0,0,0) is considered, the results would be as shown in the table below:
 Mismatching number Display Data pattern Ci i= 0 (0,0,0) 1 way i= 1 (0,0,1) (0,1,0) (1,0,0) 3 ways i= 2 (1,1,0) (1,0,1) (0,1,1) 3 ways i= 3 (1,1,1,) 1 way
These are determined by the number of bits of a word, not the row electrode selection patterns.
If the amplitude V.sub.pixel of the instantaneous voltage that is applied to the pixel had a row voltage of V.sub.row and column voltage of V.sub.column, the synthesized voltage would be as follows: EQU V.sub.pixel =(V.sub.column -V.sub.row) or (V.sub.row -V.sub.column)
Where, if V.sub.row =.+-.V.sub.r and V.sub.column =V(i), then V.sub.pixel =+V.sub.r -V(i) or -V.sub.r -V(i).
If V.sub.row =.+-.V.sub.r and V.sub.column =.+-.V(i), then V.sub.pixel =V.sub.r -V(i), Vr+V(i), -V.sub.r -V(i) or -V.sub.r +V(i).
That is: EQU V.sub.pixel =.vertline.V.sub.r -V(i).vertline. or .vertline.V.sub.r +V(i).vertline.
As a consequence, the specific amplitude to be applied to the pixel is either -(V.sub.r +V(i)) or (V.sub.r -V(i)) in the selection row and is V(i) in the non-selection row.
In general, in order to achieve a high selection ratio, it is desirable that the voltage across a pixel should be as high as possible for an ON pixel and as low as possible for an OFF pixel.
As a result, when a pixel is in the ON state, the voltage .vertline.V.sub.r +V(i).vertline. is favorable for the ON pixel, and the voltage .vertline.V.sub.r -V(i).vertline. is unfavorable for the ON pixel. On the other hand, when a pixel is in the OFF state, the voltage .vertline.V.sub.r -V(i).vertline. is favorable for the OFF pixel, and the voltage .vertline.V.sub.r +V(i).vertline. is unfavorable for the OFF pixel.
Here, it is favorable for the ON pixel to increase the effective voltage and unfavorable for the ON pixel to decrease the effective voltage. The number of combinations that selects i units from among the h bits is: EQU Ci=hCi={h!}/{i! (h-i)!}
The total number of mismatches provides the number of unfavorable voltages in the selected rows in a column. The total number of mismatches is i.multidot.Ci in Ci row select patterns considered are equally distributed over the h pixels in the selected rows. Hence the number of unfavorable voltages per pixel (Bi) when number of mismatches is i can be obtained as given following; EQU Bi=i.multidot.Ci/h (units/pixel)
The number of times a pixel gets a favorable voltage during the Ci time intervals considered is: EQU Ai={(h-i)/h}.multidot.Ci
In addition: EQU {(h-i)/h}.multidot.Ci+(i/h).multidot.Ci=(h/h) Ci=Ci
Accordingly, the following is obtained: EQU Ai=Ci-Bi={(h-1)!}/{i!.multidot.(h-i-1)!}
Where: h.ltoreq.i+1
To summarize the above: EQU V.sub.on (rms) ={(S1+S2+S3)/S4}.sup.1/2 EQU V.sub.off (rms) ={(S5+S6+S3)/S4}.sup.1/2
 ##EQU2##
In addition:
As noted above and as shown in FIG. 27, however, a liquid crystal display driven according to such a method has poor contrast between its ON and OFF states.
Moreover, as shown in FIG. 25, in such conventional driving methods, the pulse width applied to the row electrodes and the column electrodes narrows as the number of simultaneously selected row electrodes increases, and this increases the amount of crosstalk due to the distortion of the waveforms. This results in, for example, poor image quality. This problem becomes even more serious, for example, in a case in which gray shade display, which is caused by the pulse width modulation (PWM), takes place.

Drive method, a drive circuit and a display device for liquid crystal cells


A silica glass is provided for use in an optical system processing an excimer laser beam. The silica glass has a molecular hydrogen concentration of about 5.times.10.sup.18 molecules/cm.sup.3 or less and is substantially free from defects which become precursors susceptible to an one-photon absorption process and a two-photon absorption process upon irradiation of the excimer laser beam to the silica glass.

1. Field of the Invention
The present invention relates to silica glass for use in optical systems, such as lenses and mirrors, for photolithography using the wavelength ranges of 400 nm or less and of 300 nm or less, and a method of manufacturing such a silica glass.
2. Discussion of the Related Art
In recent years, VLSI chips have been highly integrated and configured to have numerous functions. In the field of logic VLSI, a so-called "system on-chip" scheme, in which a larger system is incorporated on one chip, is becoming more and more popular. Accordingly, finer pattern manufacture and higher integration are required on the silicon wafer or like substrate of such a "system on-chip" scheme. An exposure apparatus, called a stepper, or the like has been used in the photolithography technique for exposing and transcribing a fine pattern of integrated circuits onto a wafer made of silicon or the like.
In the case of DRAMs, as technology develops from LSI to VLSI, the capacity increases from 1M.fwdarw.4M.fwdarw.16M.fwdarw.64M.fwdarw.256M.fwdarw.1G. Accordingly, the minimum line width to be produced by photolithography apparatus should be increased from 1 .mu.m.fwdarw.0.8 .mu.m.fwdarw.0.5 .mu.m 0.35 .mu.m.fwdarw.0.25 .fwdarw.m.fwdarw.0.18 .mu.m.
To cope with such a trend, a higher resolution and a deeper focal depth are required for the projection lens of the stepper. The resolution and focal depth are determined by the wavelength .lambda. of exposure light and the numerical aperture (N.A.) of the lenses.
The finer the pattern, the larger the angle of the diffraction light. Therefore, the diffraction light can not be processed unless the lens has a large N.A. Also, the shorter the wavelength .lambda. of exposing light, the smaller the angle of the diffraction light. Thus, with a shorter wavelength, a relatively smaller N.A. is acceptable.
The resolution and the focal depth are expressed by, EQU Resolution=k1.multidot..lambda./N.A.
Focal Depth=k2.multidot..lambda./(N.A.).sup.2 (where, k2 and k2 are proportional constants) According to these formulae, in order to improve the resolution, either N.A. needs to be increased, or X needs to be shortened. However, as shown in the above formula, shortening A is preferable in terms of the focal depth. Therefore, the wavelength of exposing light has been reduced from the g-line (436 nm) to the i-line (365 nm), and further to excimer laser beams of KrF (248 nm) and ArF (193 nm).
Also, the optical system installed in the stepper is constructed of a plurality of optical members such as lenses. Therefore, even if the transmittance loss at each lens is small, the cumulative effects of all the lenses may lead to decrease in light amount received at the illumination surface. Thus, very high transmittance is required for each of the optical member.
Therefore, for the wavelength band of 400 nm or less, optical glass, which is manufactured by a special method taking into account transmittance loss arising from a combination of optical members, is used. For the wavelength of 300 nm or less, synthesized silica glass or single crystal fluoride, such as CaF.sub.2, is used.
As described above, one of the properties of optical members for a photolithography technique that causes deterioration in the image contrast is a transmission loss. The transmission loss is mainly caused by light absorption and light scattering in the optical member.
The light absorption is a phenomenon caused by electron transition due to photon energy incident on the optical member. When the light absorption occurs in the optical member, the absorbed energy is converted to thermal energy. As a result, the volume of the optical member increases and the refractive index and the surface condition change accordingly. In this case, the desired resolution can not be obtained.
With regard to silica glass, in particular, the synthesized silica glass manufactured by the oxy-hydrogen flame hydrolysis method using SiCl.sub.4 as a material, there is very small amount of impurity metal. Accordingly, such a glass has superior transmittance with respect to ultraviolet light.
In general, the desired specification for the transmittance of silica glass used for the optical system of precision instruments, such as photolithography-use projection lenses and illumination lenses, is about 0.1 %/cm or less in terms of the bulk absorption.
Accordingly, deterioration in the transmittance, which may occur over a short or long period of time (referred to as "solarization"), is required to be within about 0.1 %/cm or less.
In the silica glass, especially when it is irradiated by an ArF excimer laser beam, various color centers, such as ".tbd.Si." (the E' center) and ".tbd.Si--O." (NBOHC), are generated through two-photon processes from defect precursors (.tbd.Si--Si.tbd., .tbd.Si--O--O--Si.tbd.) and SiO.sub.2 primary structure (.tbd.Si--O--Si.tbd.). Such color centers cause deterioration in the transmittance for the wavelength range in use. To deal with such two-photon absorption, increasing of molecular hydrogen concentration in the glass has been proposed in order to improve the durability against laser irradiation of the silica glass.
However, even when such a conventional silica glass, which suppresses two-photon absorption processes, is used for constructing an exposure apparatus, sufficient focusing properties and adequately high enough throughput have not been achieved.

Silica glass having superior durability against excimer laser beams and method for manufacturing the same


Disclosed is an arrangement for use in transesophageal ultrasonic imaging of the heart (and other translumenal applications) in which both the position and orientation of an ultrasonic probe that generates an ultrasonic scanning pattern is determined in terms of a three-dimensional coordinate system that lies outside the patient's body and is produced by a magnetic field generator. The arrangement provides two-dimensional multi-planar scanning in which the ultrasonic scanning pattern is selectively positionable relative to rotation about two orthogonal coordinate axes that are mutually orthogonal to the longitudinal axis of the ultrasonic scanning probe. Provision is made for generating electrical signals indicative of rotational position of the scanning pattern relative to each of the two axes of rotation. The signals representative of the rotational position of the scanning pattern allow registration between the two-dimensional multi-plane ultrasonic images for purposes such as a computer generation of three-dimensional cardiac images. The ultrasonic probe also includes a flexure region for selectively positioning the probe in the esophagus or other lumen and a heart sound microphone for use in temporal registration of the ultrasonic imaging relative to one or more events in the cardiac cycle.

Ultrasonic scanning has become accepted practice in various medical applications including research, diagnosis and patient monitoring. In the vast majority of such medical applications, a transducer produces an ultrasonic beam that is placed in close proximity with tissue or organs to be examined and the beam is mechanically or electronically swept through a fan-shaped or other scanning pattern. Reflection (backscatter) of the ultrasonic energy results in "echo" image signals that can be processed for visually displaying ultrasonically imaged tissue and organs and/or stored in digital or other format for subsequent computer or manual analyses.
Ultrasonic scanning of the heart (echocardiography) has presented special challenges and problems because of the relatively complex movement of the heart and dynamic changes in the heart's configuration that occur during the cardiac cycle. Because of such problems and others, cardiac ultrasonic scanning historically has been limited to two-dimensional imaging in which an ultrasonic transducer is positioned as accurately as possible relative to obtaining ultrasonic scanning of the heart along a desired plane. Two basic scanning techniques have been employed: transcutaneous and translumenal. In translumenal ultrasonic scanning, a probe that includes an ultrasonic transducer is passed along a patient's throat and is positioned in the esophagus (or stomach) where it is near the heart and an ultrasonic image can be obtained without interference of the lungs or ribs (which can present a problem in transcutaneous echocardiography). Because the esophagus extends downwardly along the long axis of the heart, multiple scanning points are available to thereby provide multiple ultrasonic images. Moreover, because the heart is in close proximity with the esophagus, a relatively high scanning frequency can be employed (often on the order of 5 megahertz), which results in higher image resolution than can be obtained with lower frequency transcutaneous scanning. In addition, esophageal echocardiography has become the technique of choice for patient monitoring during surgery because the ultrasonic probe is located outside the surgical field.
In recent years, a fair amount of effort has been devoted to the development of techniques and equipment for three-dimensional ultrasonic cardiac imaging. From the clinical standpoint, motivation for developing three-dimensional echocardiography includes imaging portions of the heart that might be missed in two-dimensional scanning and, in addition, providing a methodology for diagnosing and evaluating cardiac performance. Further motivation is provided because of the portability and relatively low cost associated with ultrasonic scanning. One of the most promising techniques for obtaining clinically applicable three-dimensional echocardiography is the use of computer graphics to produce a three-dimensional image of the heart on the basis of a number of transesophageal two-dimensional ultrasonic images that are taken along different cardiac planes.
Various problems are associated with attempting to construct a three-dimensional image of the heart from multiple two-dimensional ultrasonic images. The primary problem is that the spatial relationship (position and orientation) between the two-dimensional images is difficult to ascertain. Further, difficulty can be encountered in positioning an ultrasonic probe to obtain a desired two-dimensional cardiac image. In addition, it is desirable to obtain the two-dimensional images with a multi-planar ultrasonic probe, which can obtain a number of two-dimensional images from a single imaging site. Specifically, multi-planar imaging from a single imaging site is more suitable for use in patient monitoring applications and lessens the risk of esophageal irritation. Although multi-planar ultrasonic scanning probes are advantageous from the operational standpoint, difficulties are encountered relative to the size of such probes, especially for use with patients who are not sedated.

Method and apparatus for three-dimensional translumenal ultrasonic imaging


In addition to an engine-braking master piston, an exhaust-gas-recirculation master piston is provided to pressurize an oil having been supplied to an oil passage and open an exhaust valve in a suction stroke. A directional control valve selectively switches transmission of hydraulic pressures produced by the engine-braking and exhaust-gas-recirculation master pistons so that the exhaust valve adjacent to a top dead center in a compression stroke is opened to discharge the compressed air. Exhaust gas recirculation can be effected while braking action by a braking force produced in the compression stroke is ensured.

The present invention relates to an internal combustion engine with a compression engine brake, said engine brake being utilized for exhaust gas recirculation.
In a conventional engine brake for an internal combustion engine as shown in FIG. 1, upon engine braking with an exhaust brake valve 10 being closed, a master piston 2 for a cylinder 7 is actuated through a rocker arm by a push rod 1 of another cylinder (not shown) to pressurize an oil having been supplied to an oil passage 5 from a rocker shaft support through solenoid and control valves 3 and 4. Then, the compressed oil urges a slave piston 6 to open an exhaust valve 8 adjacent to a top dead center of the cylinder 7 in a compression stroke and discharge the compressed air through an exhaust port 9, so that no force for pushing a piston in the cylinder 7 generates and a braking force obtained in the compression stroke is effectively utilized with no loss.
The conventional engine brake of this type, which is very effective for engine braking, cannot serve for exhaust gas recirculation and therefore cannot contribute to reduction of NO.sub.x and suppression of white smoke at engine starting. Generally, exhaust gas recirculation is difficult to effect especially in turbo-intercooled engines.
The reason for this is that; in most engine operating conditions, the intake manifold pressure is higher than the exhaust manifold pressure.
A primary object of the present invention is therefore to provide all internal combustion engine which overcomes the above-described problems.


A juvenile chair has a seat portion, a back rest connected to the seat, two front legs and two back legs with each leg being pivotally connected to the seat portion. A pair of braces is included each of which respectively connects a front and back leg on each side of the chair. A cross brace removably connected to the pair of braces holds the legs in normal chair position, or on disconnection can be reconnected to the braces when the legs are pivoted upward so that they extend above the seat. A juvenile table having a table top, a joint and a support base is provided with the joint connecting the table top to the base. The joint has an outer sleeve with resilient flexible support structure disposed therein and spaced from the internal walls of the sleeve and connected to the table top so that the table top is free to move up and down, rock from side to side, or rotate. Carrier supports attached to the underside of the table, receive the cross brace of the juvenile chair when the legs are folded upwardly whereby a plurality of similar juvenile chairs can be pivotally attached to the table and the combination used as a merry-go-round.

Young parents or grandparents shopping for walkers, high chairs, strollers, rockers, car beds, car seats, cribs, carriages, chairs, swings, bathinettes and other baby holding and amusement devices are certain to experience frustration and confusion in trying to decide on their purchase. They are confronted with an almost endless choice of individual items of specific function and utility. If storage facilities and expense are of no great concern, they might buy all of the above items; all are important at one time or another for utilitarian and/or amusement purposes. But what of the great masses of parents to whom money and storage space are major problems? Obviously, those living in apartments and under strict budgets cannot afford all of the above items. It is to these parents of average means and limited storage space that the present invention is primarily directed.
The present invention provides a unique joint which may be used as part of a system with one, two or three or more different child holding devices or carriers and various wheeled or wheeless supports or bases therefor. The system comprising the above components are relatively inexpensive and require significantly less storage space as compared with the many individual items mentioned above and provide all of the needs and functions of such individual items, and more.
Furthermore, with respect to walkers for pre-walking children, those available until now have been useful primarily in allowing the child to move from one point to another providing minimal amusement to the child.
The unique joint or stem of the invention when employed in a walker makes available to the child seated therein not only locomotion but almost endless variations on motion and amusement as well. As will be seen hereinafter, the walker incorporating the unique joint of the invention will rock, bounce up and down, sway or swing from side to side and back and forth, tilt and be positioned at any desired angle between horizontal and vertical and back to its normal vertical position, and turn or spin 360.degree. in either direction. The parent may lock the walker in any desired altitude including in a normal locked position so that the walker functions strictly as does a conventional walker or even in a rigid position where no movement of any kind is desired.
Accordingly, it is seen that the unique joint of the invention when employed in a walker or other type system will provide an economical solution and substitute for the myriad types of child holding and amusement apparatus usually required for the average active, curious child.

Folding juvenile chair attachable to a table top


Aspects of the present invention relate to systems, methods and apparatus for securing equipment to a structure. Some aspects relate to an apparatus with clamp flanges and a clamping mechanism that engages a piece of equipment and secures the equipment from tipping or other movement relative to an attached structure such as a vehicle bed, storage container or display platform. Some aspects relate to an actuating clamp arm working in conjunction with a lateral retainer spring arm to effectuate a clamping action on the equipment to be secured.

Construction site preparation, roadway construction, underground utility installation and other construction projects typically require the use, transportation and storage of portable construction equipment such as soil compaction rammers, vibratory plates, core drills and other equipment that is relatively tall, narrow and heavy, but is typically kept in an upright position where it is susceptible to tipping over. This type of equipment is preferably stored and transported in the upright position because it takes up less space and doesn't need to be manually manipulated into other positions and gasoline and other fluids do not leak out of their tanks. This type of equipment is also heavy for a single individual to manipulate and can cause severe back strain when moving from a horizontal position to the upright position.
What is needed is a compact device that can securely hold this type of equipment in an upright position during transport and/or storage.


To improve the exhaust heat recovery efficiency, a compressor includes a heat exchanger for cooling a gas, coolant, water, or oil heated by the compressor during compressor operation by heat exchange with a working fluid, for circulating the working fluid of a Rankine cycle. The Rankine cycle is implemented by the heat exchanger, an expander, a condenser, and a circulating pump to circulate the working fluid through the cycle.

In compressors, a large amount of heat is generated, for example, at the time of air compression. This causes the temperature of compressed air to rise. Compressed air may be used at high temperature, however, generally it is cooled to close-to-ambient temperature and also dehumidified for its use. Also, in compressors, oil or water may be used for lubrication or cooling, and the oil or water heated to a high temperature is cooled. The heat generated in compressors in this manner is exhausted through compressed air, oil, water, or the like. As one of the devices for recovering such exhaust heat, a device with thermoelectric conversion elements installed in a compressor body and discharge piping has been proposed (for example, see Japanese Published Unexamined Patent Application No. 2006-125302). According to the related art disclosed in Japanese Published Unexamined Patent Application No. 2006-125302, heat from high-temperature portions such as the compressor body and the discharge piping is converted to electric power by the thermoelectric conversion elements, and the voltage is converted through a regulator so as to supply power to auxiliary devices such as a cooling fan and an oil pump.

Hitachi Industrial Equipment Systems Co., Ltd.


A storage console includes a housing having a storage chamber, an access opening and a guide track. The storage console also includes a tambour door including an articulated substrate and a plurality of slats carried on the articulated substrate. The articulated substrate includes integral overmolded guides and integral overmolded splines.

Storage consoles incorporating a tambour door are known in the art. See, for example, U.S. Pat. No. 6,250,729 owned by Ford Global Technologies, LLC.
This document relates to a new and improved hard tambour door execution that allows for a multitude of finish options including, for example, painted/filmed plastic, wood, aluminum, carbon fiber, metal mesh or the like. The new and improved tambour door also delivers quiet operation with smooth and consistent effort throughout the length of travel when displacing the tambour door between fully opened and fully closed positions.

Tambour door and storage console incorporating a tambour door


A lock for the retention of articles such as box wrenches supported in place on a holder and including a barrier closely overlying the articles. Posts on the barrier include flexible segments for insertion into openings for locked engagement with the holder to retain the barrier in proximate the articles to prevent article removal from the holder. The flexible segments may be fractured by a purchaser for access to and removal of the articles.

The present invention pertains generally to racks or holders on which hand tools and other articles are displayed or stored with such holders oftimes being used for displaying the tools in a retail establishment.
It is common practice in the marketing of hand tools to display articles such as a set of wrenches, screwdrivers, etc., supported in place on a holder with the holder being useable thereafter for orderly tool storage. A problem exists in displaying of hand tools, some being of considerable cost, in retail establishments in that some tool holders permit tool removal and concealment permitting theft of the tool. In an attempt to thwart such theft some tool manufacturers have resorted to shrink wrapping or the bubble packaging of tools but have found that such packaging is costly. Further, such packaging may or may not include a useable holder for later use by the purchaser for orderly storage of the tools. A further drawback is that such packaging prevents a prospective purchaser from closely examining the tools resulting in loss of a sale by the retailer. It is important in the merchandising of tools that the same be displayed for view by the prospective buyer. The theft of tools from store shelves and racks constitutes a problem for most retail establishments as tools are typically highly portable and readily concealable.

Lock securing elongate articles to a holder


A two-bolt lockset simultaneously locks and unlocks in response to a single action by an operator, such as a key and cylinder. A deadbolt couples to such an operator to project and lock or retract and unlock. A crank also responds to the locking of the deadbolt to move a slide that engages and locks an actuator of the second bolt, a latch bolt, to lock the latch bolt. The slide is biased away from the latch bolt so that upon retraction of the deadbolt and corresponding motion of the crank, the slide is freed of the crank and moves out of engagement with the actuator. Preferably, the slide is carried by a retractor so that both locks clear by the single turn of a single inside operator. The retractor responds to a retractor cam attached to the inside operator to translate. The slide moves out of engagement with the actuator upon such movement and forces the crank to withdraw the deadbolt.

The present invention relates to locksets in general, and more in particular to double bolt locksets.
Locksets for the security of habitated and other space have taken a variety of forms. One form provides a key in a knob. This type of lockset is extremely convenient. It has a spring latch bolt biased to an extended position so that upon closing a door, the door stays shut without more. The latch bolt can be locked to lock the door. However, the security of the lockset is low. The projection of the latch bolt is short and therefore springing the door or door jamb to release the latch is a distinct possibility. This lockset also suffers because it breaks easily. For example, the knob can be pried off with a tube, exposing the latch to easy retraction.
A second type of lock is a mortise lock. These locks are considerably less vulnerable and are of much stronger construction than key-in-the-knob locks, but they too have fallen into disfavor in recent years. A mortise lock requires a large cutout space in the door to receive a large lock case that contains the lock mechanisms. The space weakens the door. A good swift kick near the lock can often split the door and permit entry. Mortise locks are also expensive to install and to make.
A third type of lock is the deadbolt lock. A deadbolt may be extended and retracted with a key from the outside, and the likes of a thumb turn from the inside. If this lock is well constructed, it can offer the best security of any of the locks discussed here. The deadbolt lock does not require the large cutout space that a mortise lock requires and can provide a bolt that projects substantially for cooperation with a deep hole associated with the door jamb. The difficulty with deadbolts is that they require the use of a spring latch bolt to retain the door closed when the deadbolt is retracted and the door is unlocked.
Notwithstanding this defect in deadbolts, in recent years it has been the trend to construct locksets by combining both a deadbolt and a spring latch bolt. Some of these constructions have the deadbolt only locking. Others lock both the deadbolt and the latch bolt. Clearly, when a latch bolt locks, it is necessary to provide some mechanism for this purpose, such as a cylinder, pusher turn button, or the like.
Obviously, there is substantial inconvenience in a double locking lockset in having to independently unlock both the latch bolt and a deadbolt. Some constructions employing both a deadbolt and a latch bolt simultaneously retract both the deadbbolt and the latch bolt by actuation of a single inside operator, such as an inside knob.
U.S. Pat. No. 3,910,613 to Roger Nolin describes an elegantly simple lock that permits the simultaneous opening of a spring latch and deadbolt in a surface-mounted lockset. But the patent does not describe a simultaneously locking and unlocking latch bolt and deadbolt.
Simultaneous locking and unlocking locksets have been found in mortise-type locks, such as shown in U.S. Pat. No. 3,337,248 to Fred J. Russell and Roger J. Nolin. In mortise-type locks all the components, the deadbolt mechanisms, latch bolt mechanisms, key mechanisms, and retracting mechanisms, are located in the same case in close proximity to each other. Accordingly, it is comparatively easy to arrange the components at will. Even with the attraction of mortise-type locks in the ability to simultaneously lock and unlock both a deadbolt and a latch bolt, these locks still offer poor security, and suffer because of high installation and construction cost.
It has also been recognized that locksets providing a panic proof exit capability are highly desirable. This type of lockset retracts both a lock bolt and a latch bolt with a single operation on the inside of a door. U.S. Pat. No. 3,910,613 referenced above is an example of such a panic proof lockset.
U.S. Pat. No. 3,791,180 to William J. Doyle illustrates a different construction for a panic proof lockset in a surface-mounted lockset. This construction uses a gear sector to interconnect deadbolt and latch bolt assemblies. The construction shows separately keyed lock bolts and latch bolts. Doyle does not provide for simultaneous locking and unlocking of both a deadbolt and a latch bolt with but a single operation from either inside or outside of a door.
U.S. Pat. No. 3,390,558 to Torno et al shows a complicated lock having many desirable features. It is panic proof and has a latch bolt and deadbolt that can be simultaneously opened from either inside or outside of a door. This construction, however, does not provide a lockset that has a latch bolt and a deadbolt that simultaneously lock or unlock.
The latch bolt is independently locked with push turn bottom on the face of the inside knob. Turning the outside key retracts the deadbolt and the latch bolt, but the latch bolt remains locked. The control on the knob face has to be manually operated to unlock the latch.

Two-bolt lockset with simultaneous locking and unlocking of its bolts