Tubular connections and methods of designing tubular connections having selected root/crest clearance when the box member and pin member are made-up. When the tubular connection is radially expanded, a thread seal is formed over at least part of the tubular connection.

Casing joints, liners, and other oilfield tubulars are often used in drilling, completing, and producing a well. Casing joints, for example, may be emplaced in a wellbore to stabilize a formation, to protect a formation against elevated wellbore pressures (e.g., wellbore pressures that exceed a formation pressure), and the like. Casing joints may be coupled in an end-to-end manner by threaded connections, welded connections, and other connections known in the art. The connections may be designed so as to form a seal between an interior of the coupled casing joints and an annular space formed between exterior walls of the casing joints and walls of the wellbore. The seal may be, for example, an elastomeric seal (e.g., an o-ring seal), a metal-to-metal seal formed proximate the connection, or similar seals known in the art. In some connections, seals are formed between the internal and external threads. Connections with this characteristic are said to have a "thread seal." As used herein, a "thread seal" means that a seal is formed between at least a portion of the internal thread on the box member and the external thread on the pin member.
FIG. 2 shows a cross section of a prior art made-up tubular threaded connection with wedge threads as disclosed in U.S. Pat. No. RE 30,647 issued to Blose, which is assigned to the assignee of the present invention and incorporated herein by reference. Wedge threads are characterized by threads with increase in width (i.e. axial distance between flanks 208 and 209) in opposite directions on the pin connection 201 and box connection 2000. Wedge threads are extensively disclosed in U.S. Pat. No. RE 34,467 issued to Reeves, U.S. Pat. No. 4,703,954 issued to Ortloff, and U.S. Pat. No. 5,454,605 issued to Mott, all assigned to the assignee of the present invention and incorporated herein by reference. This made-up connection consists of female box connection 200, and male pin connection 201. The made-up connection has overall connection length 202 (or the quantity L1) from pin nose 203 to box nose 204, and engaged thread length 205 (or the quantity L2) from the beginning of first engaged thread on the pin 206 to the end of last engaged thread on the pin 207. Note that engaged thread length 205 cannot always be measured in the same axial plane as implied by FIG. 2, as the start of the first engaged thread will not always lie in the same axial plane as the end of the last engaged thread.
The wedge thread-form has stab flanks 208, so called because they generally come into contact when the threaded connection is initially "stabbed" together to be made-up. The stab flanks 208 support the weight of the tubular before the connection is fully made-up. The thread-form also has load flanks 209, so called because they carry tensile load exerted on a made-up connection within a string of casing hanging in a wellbore. The thread-form on pin connection 201 has pin thread roots 210 and pin thread crests 211. The thread-form on box connection 200 has box thread roots 212 and box thread crests 213.
Referring to FIG. 2, one distinction between U.S. Pat. No. RE 30,647 issued to Blose and U.S. Pat. No. RE 34,467 issued to Reeves is that Blose discloses a wedge thread with clearance between the pin thread crest 211 and box thread root 212 and between the box thread crest 213 and pin thread root 210, while Reeves discloses a selected amount of interference between the roots and crests. Root-crest interference, in addition to the stab flank and load flank interferences inherent in wedge threads, provides a thread seal. This thread seal can provide a backup to other sealing mechanisms, or it can be used alone. The clearance disclosed by Blose is shown as gap A and gap B in FIG. 2. Wedge threads as disclosed by Reeves have replaced those taught by Blose in part because gaps A and B prevent the connection from being able to seal high pressures.
In some well construction operations, it is advantageous to radially plastically expand threaded pipe or casing joints in a drilled ("open") hole or inside a cased wellbore. In a cased wellbore, radially expandable casing can be used to reinforce worn or damaged casing so as to, for example, increase a burst rating of the old casing, thereby preventing premature abandonment of the hole. In open hole sections of the wellbore, the use of radially expandable casing may reduce a required diameter of a drilled hole for a desired final cased hole diameter, and may also reduce a required volume of cement required to fix the casing in wellbore.
An expansion tool is typically used to plastically radially expand a string of casing or tubing disposed inside a wellbore from an initial condition (e.g., from an initial diameter) to an expanded condition (e.g., with a larger diameter). One common prior-art expansion process uses a conically tapered, cold-forming expansion tool 101 (commonly referred to as a "pig") shown in FIG. 1 to expand casing in a wellbore. The expansion tool 101 is generally sealed inside of a pig launcher (not shown), which is a belled section attached to a lower end of a casing string that is run into the wellbore. Because the pig launcher must pass through the parent casing already installed in the wellbore, the pig launcher has an outer diameter that is less than a "drift diameter" of the parent casing. As used herein, the "drift diameter" is the maximum external diameter that can pass through a wellbore or casing installed in the wellbore. Generally, the drift diameter is somewhat smaller than the internal diameter of the wellbore or casing due to the wellbore not being perfectly straight. Because of this, a tool having exactly the internal diameter of the parent casing would be unable to move freely through the parent casing.
Typically, after running the casing string into the wellbore, the casing string is suspended inside the wellbore using slips (not shown). Then, drill pipe (not shown) is run into the wellbore and latched onto the expansion tool 101. After connecting the drill pipe, the weight of the casing string is supported by the expansion tool 101. The drill pipe is then used to further lower the casing string to the selected location in the wellbore. The expansion tool 101 includes a tapered section 98A having a taper angle 98B that is generally between 5 degrees and 45 degrees. The expansion tool 101 is generally symmetric about a longitudinal axis 97 thereof. The expansion tool 101 also includes a cylindrical section 96 having a diameter that corresponds to a desired expanded inner diameter of a casing string (not shown) that is followed by a tapered section 95. Note that in some instances, an expansion tool 101 may not have a cylindrical section 96.
The next step in this exemplary expansion process is to pump cement through the drill pipe and out of a cement port on the pig. The cement flows between the outside of the casing string to be expanded and the inside of the wellbore. After the selected amount of cement has been pumped, the cement port is sealed off, typically by a dart designed to seat in the cement port. The dart is usually pumped with drilling fluid through the drill pipe. Continuing to pump drilling fluid pressurizes the pig launcher, which drives the expansion tool 101 forward (i.e. upward toward the surface) and the casing further into the wellbore. As the expansion tool 101 moves forward, the casing string expands. Expansion generally continues until the entire casing string has been expanded. Depending on the length of expansion to be performed, the expansion process may be performed in length increments to remove lengths of drill pipe as the expansion tool 101 progresses upward. In many instances, the casing string will include a length of casing that remains inside the parent casing after expansion. The extra length of casing can be designed to act as a liner hanger for the casing string and to seal between the parent casing and the expanded casing string.
In this expansion process, a rate of radial expansion is determined by, for example, a total plastic strain required to expand the casing string, the taper angle 98A, and a rate of axial displacement of the expansion tool 101 through the casing string. Consistency of the expansion process is controlled by transitions along the expansion tool 101 and a cross-sectional area of, for example, lengths of casing that form the casing string, threaded connections that couple the length of casing, and the like.
The expansion tool 101 may be started at either the bottom or the top of the casing string depending on the tool design and the application. Radial expansion may be performed at rates of, for example, 25 to 60 feet per minute. Other expansion processes, such as expansion under localized hydrostatic pressure, or "hydroforming," are known in the art, but are generally not used as much as cold-forming expansion processes. Other expansion tools for cold-forming the casing also exist. Various tools exist for use in cold-forming expansion processes.
A common problem with radial expansion of casing is that the connections can be damaged during the expansion process. Part of this damage is because the connections are stressed during make-up to ensure that the connections remain made-up while being installed in the wellbore. The additional stress experienced by the connections during radial expansion can cause the connection to fail. Typically, it is the box member that splits. Even if complete failure does not occur, connections may lose the ability to form a hydraulic seal. Connections that utilize metal to metal seals or thread sealing can lose the ability to seal after the deformation caused by radial expansion.
While various expansion methods, in particular the tapered expansion tool method, have proven to work quite well on casing strings, the expansion of made-up threaded connections can result in structural sealing problems. Threaded connections that undergo radial plastic expansion have a tendency to exhibit a non-uniform axial elongation and react differently to residual hoop stresses remaining after expansion. Specifically, male (pin) threaded members and female (box) threaded members deform differently during radial expansion. The box member will generally move away from the pin member during radial expansion. This is due in part to the relief of residual stress in the connection that exists from the make-up of the box member with the pin member. The radial movement of the box member from the pin member relieves some of the residual stress. This differential displacement phenomenon can result in a loss of preload in axially-engaged seals, making the use of conventional metal-to-metal seals (including, for example, shoulder seals) problematic for plastically radially expanded casing and tubing.
One of the more successful thread-forms for expandable casing applications is the wedge thread. One reason that wedge threads are a suitable thread-form for expandable casing applications is that they may not make-up against a radial torque shoulder (i.e. a positive stop), but instead typically make-up by nearly simultaneous contact of thread load flanks 209 and stab flanks 208. During the expansion process, axial stress in the connection will often cause a radial torque shoulder to fail when the compressive stresses at the shoulder exceed the compressive yield strength of the casing material. The advantages of a wedge thread are independent of the thread form used. When a dovetail-shaped or another closed thread form is used for the wedge thread, the wedge thread will also resist radial forces during and after expansion, which might tend to separate the pin connection from the box connection. An open thread form for the wedge thread may also be used, such as that taught by U.S. Pat. No. 6,578,880 B2, issued to Watts, and incorporated herein by reference.
As discussed above, the additional stress experienced by a connection during radial expansion can cause the box member to fail, or cause the connection to lose the ability to form a thread seal or metal to metal seal. The structural integrity and sealing ability of a connection are still needed after expansion. Thus, preventing the damage to the connection and providing a thread seal after expansion are highly desirable goals. Designing a connection for the purpose of being radially expanded could prevent failure of the box member and potentially maintain a thread seal.


A positive crankcase ventilation (PCV) system includes: an oil separator separating oil from blow-by gases; a PCV valve allowing the blow-by gases from which the oil has been separated by the oil separator to flow into intake ports of a cylinder head; a PCV passage vertically extending from the PCV valve; a PCV chamber connected to the PCV passage; and a plurality of bypass passages branching off from the PCV chamber to the intake ports, respectively.

An internal combustion engine is a device that produces power by burning air and fuel. When the internal combustion engine is operated, blow-by gases are generated in the compression stroke and the expansion stroke. Blow-by gases are combustion gases, which flow into a crankcase through gaps between piston rings and the wall of a combustion chamber by the force of the high-pressure gases produced in the combustion process.
When the blow-by gases are introduced into the crankcase, pressure increases in the crankcase, and the high-temperature blow-by gases may deteriorate or oxidize the engine oil contained in an oil pan of the crankcase. Thus, it is necessary to discharge the blow-by gases introduced into the crankcase. A positive crankcase ventilation (PCV) system may be configured to recirculate the blow-by gases in the crankcase to an intake system of the internal combustion engine.
The PCV system may include an oil separator disposed on the cylinder head side and a PCV valve allowing the blow-by gases from which oil has been separated by the oil separator to flow into the intake system of the internal combustion engine. The oil separator may be configured to separate the oil from the blow-by gases collected from the crankcase through a collection passage. After the engine is started, the PCV valve is opened by negative pressure generated on the intake system side The opening of the PCV valve allows the blow-by gases to flow into the intake system of the internal combustion engine.
Meanwhile, a conventional PCV system includes a PCV hose connecting between a PCV valve and an intake manifold of the internal combustion engine The blow-by gases flow into the intake manifold of the internal combustion engine through the PCV hose.
In the conventional PCV system, since the PCV hose is exposed to the outside of the internal combustion engine, freezing has frequently occurred in the PCV hose due to vehicle-induced wind (driving wind) while the vehicle is driving in the winter, resulting in abnormal combustion of the internal combustion engine. As for the blow-by gases introduced into the intake manifold, the flow rates of blow-by gases flowing into respective cylinders are different due to a length difference between runners of the intake manifold. In addition, an assembly process of the PCV hose is very troublesome, which reduces the assembly quality.
In order to solve the aforementioned problems, a unitary one-piece structure in which a blow-by gas passage is integrally formed inside the intake manifold has recently been proposed. Because such a unitary one-piece structure is formed by embedding the blow-by gas passage in the intake manifold, it may partially prevent freezing. However, since the intake manifold is located in the foremost position of an engine compartment, freezing caused by the wind blowing into the engine compartment may not be completely prevented. In some very cold regions, freezing problems may still occur.
According to the related art, since the blow-by gas passage is determined in accordance with the shape of the intake manifold, the blow-by gases may not uniformly flow into multiple runners, resulting in different flow rates of the blow-by gases flowing into respective cylinders.
Meanwhile, the oil separator separates the oil from the blow-by gases introduced from the crankcase into the cylinder head However, it is practically impossible for the oil separator to completely separate the oil from the blow-by gases. That is, even though the blow-by gases pass through the oil separator, a small amount of oil is still contained in the blow-by gases.
As such, the blow-by gases from which the oil has been separated by the oil separator still contain a small amount of oil. If the blow-by gases are not uniformly distributed to the respective cylinders of the internal combustion engine and instead are intensively or excessively introduced into one cylinder, there is a high possibility that abnormal combustion occurs in the corresponding cylinder. Thus, the PCV system needs to uniformly distribute the blow-by gases to the cylinders to prevent the abnormal combustion.
The above information described in this background section is provided to assist in understanding the background of the inventive concept This background section may thus include any technical concept which is not considered as the prior art that is already known to those of ordinary skill in the art.


A method and system for tracking attitude of a device includes fixing a two-dimensional array of photosensors to the device and using the array to form a reference frame and a sample frame of images. The fields of view of the sample and reference frames largely overlap, so that there are common imaged features from frame to frame. Sample frames are correlated with the reference frame to detect differences in location of the common features. Based upon detection of correlations of features, an attitudinal signal indicative of pitch, yaw, and/or roll is generated. In the preferred embodiment, the attitudinal signal is used to manipulate a screen cursor of a display system, such as a remote interactive video system (RIVS). However, attitudinal tracking using the invention may be employed in other applications. Another aspect of the invention is that the two-dimensional array is configured to compensate for any curvilinear distortions introduced by a lens system for imaging the features within the field of view of the array.

The invention relates generally to methods and systems for tracking attitude of a device and more particularly to tracking the attitude of a device in order to control a device or process, such as a cursor of a video display.
There are applications in which video systems require that a person interact with information presented on a display screen. At times, the interaction is to occur while the person is situated at a distance from the display screen. As will be described more fully below, the interaction may be accomplished by remotely controlling a screen cursor in one of a variety of manners. The interactions may include selecting from a variety of choices presented as a screen menu, or xe2x80x9ctypingxe2x80x9d text using an on-screen keyboard. Examples of remote interactive video systems (RIVS) include interactive television (ITV), TV-style Internet browsers, and conference-room video projectors.
One key component of a RIVS is the xe2x80x9cpointingxe2x80x9d device for controlling the on-screen cursor. The pointing device fulfills a function analogous to that which mice, trackballs, and graphic tablets perform for computers. However, the environment for RIVS presents difficulties that are typically not encountered in operation of a computer. For example, an operator of a RIVS is typically further away from the controlled device than is the operator of a computer. As another example, the operator of a RIVS is more likely to be in an unstructured immediate environment, e.g., an ITV operator seated across a living room from a television set. In many situations, the environment precludes use of conventional computer pointing devices, such as mice. Moreover, a RIVS is rarely equipped with a keyboard, so that the pointing device may have to accommodate the extra burden of providing a text entry.
There are a number of known pointing devices for a RIVS. Most of the known pointing devices implement some variation of a four-key cursor pad on a hand-held controller. The four-key cursor pad is manipulated to step the screen cursor up, down, left or right among various menu choices. Such interfaces emulate the computer keyboard cursor keys used with old-style textural interfaces. However, these interfaces are typically much slower and less intuitive to use than computer mice and other pointing devices developed for modern graphical software interfaces.
In an effort to improve upon cursor control within the RIVS environment, more advanced computer pointing devices of mice and trackballs have been adapted. In one adaptation, a miniature trackball is mounted atop a controller, with the trackball being operated by the person""s thumb. The trackball controller is faster than the use of cursor keys and facilitates diagonal moves. Unfortunately, the trackball may require repeated strokes to accomplish large cursor movements and, in general, thumb control taxes the user""s thumb dexterity. For example, it is difficult to trace the cursor in a circle on the display screen.
The use of a mouse for ITV cursor control has been demonstrated. The advantage of the mouse is that it provides excellent and intuitive cursor control. The concern is that there may not be a suitable planar operating surface that is convenient to the operator.
A further refinement in the RIVS pointing art is the use of devices that enable control of a cursor by merely gesturing with a controller. These devices may measure the attitude, i.e. pitch, yaw, and possibly roll, of the controller. A first category of such an approach employs light beams to measure attitude. PCT International Publication Number WO 95/19031 describes a system for determining the pointing orientation of a remote unit relative to a fixed base unit. The fixed base unit includes one or more light sources for emitting a light beam. The emitted light is polarized in at least one predetermined orientation. The movable remote unit includes a photodetector for detecting the polarized emitted light. The attitude of the movable remote unit may be determined by measuring the intensity of received light from various directions.
Another implementation of the emitted-light category of measuring attitude is one in which an infrared (IR) signal is beamed from the area of the video display. The IR signal is defocused and is imaged onto a quad photodiode array in the controller. The relative signal amplitudes from the four photodiodes may be used to determine the relative orientation of the controller to a line drawn from the display. One concern is that the system may undesirably flood the room with intense IR, rendering other nearby IR-coupled appliances (e.g., a VCR controller) inoperative. A second concern is that the limited range of transmission of defocused IR signals may render this system of measuring attitude unreliable when the controller is more than a relatively short distance from the video display.
A second category of devices that measure attitude of the controller is one in which inertial navigation principles are employed. Gyroscopes or encoded gimballed masses establish inertial frames in the controllers, against which attitude changes can be measured. The attitude information may then be transmitted to the video display via a radio-frequency link to a small dipole antenna affixed atop the video display.
The third category is related to the first category. A hand-held object that provides cursor control has a number of light sources mounted on one surface. A single electronic camera is directed to capture images of the light sources mounted on a hand-held object. Locations of the images of the light sources are detected in each camera image, and a computer is used to determine the attitude of the light-emitting hand-held object. Such a device is described in U.S. Pat. No. 5,338,059 to DeMenphon.
A closely related need exists in the field of virtual reality. In games, simulations, and other visualization situations, it is often necessary to encode the attitude of a user""s head, or other body part. In many cases, systems for encoding head pitch and yaw may be applied to RIVS controllers, and vice versa. One known virtual reality system encodes pitch and yaw by means of instrumented compasses and gravimeters.
While the known cursor control devices and attitude-determining systems operate adequately for their intended purposes, each is associated with a concern or a problem. Operation may be slow or tedious, or may require use of a specific operating surface. Devices and systems that include IR radiation may adversely affect operation of other devices. Attitude-sensing devices that are based on gravity may have difficulty in distinguishing tilting from transverse acceleration, thereby rendering control erratic. This last problem conceivably could be solved by gyro stabilization, but the cost and power consumption make this solution unattractive. Known systems that utilize light detection require adding a second contrivance at the display, again adding additional cost.
What is needed is a method and a system for reliably tracking attitude of a device. What is further needed is such a method and system that is cost efficient when used in controlling a screen cursor or when used in other remote interactive video applications.
Correlation of successive images acquired by means of a two-dimensional array of photosensors is used as a basis for tracking attitude of a device to which the array is affixed. In the preferred embodiment, the device is a hand-holdable member, such as a controller for maneuvering a cursor on a display screen of a video set. Based upon the step of correlating images to detect differences in location of imaged features that are common to a succession of images, the system generates an attitudinal signal indicative of any changes in angular orientation during the time period of acquiring the images. That is, the attitudinal signal is determined by the pitch and yaw, and optionally the roll, of the device that bears the array of photosensors. Since the acquired images need not be related to that which is being controlled, e.g. a screen cursor, the device can face in any direction during the control process. Moreover, it is not necessary to provide a dimensional one-to-one correspondence of angular displacement of the device and travel of that which is being controlled. Within cursor control, for example, the controller may be directed arbitrarily and relationships of degrees of pitch and yaw to lengths of cursor movement may be user-adjustable.
The two-dimensional array of photosensors is used to acquire a reference frame for tracking the attitude of the device. The reference frame is stored and a second image of features within a field of view of the array is acquired. The second image may be considered to be a sample image, and the fields of view of the two images should be largely overlapping, so that the reference and sample frames include a number of common features. While not critical, the device includes optics which provide a focus nominally at infinity, intentionally presenting an off-sharp image to the array of photosensors. In the application of the device for controlling a screen cursor, the representative imaged features will typically include windows, lamps, furniture and the display screen itself. In any application of the invention, one or more stationary sources of light may be specifically added within the environment to be imaged, so that successive images of the fixed light are used for the purpose of correlation. In one implementation of such an embodiment, the source of light is an IR emitter and the imaging array on the device is provided with IR filtering to permit tracking of the attitude of the device.
Conceptually, the step of correlating the reference frame with a sample frame is one in which one of the frames is fixed in position and the other frame is repeatedly shifted to determine which shifted position best approximates an alignment of the imaged features that are common to the two frames, thereby allowing the determination of the pitch and yaw of the imaging array during the interval between acquiring the two frames. In practice, the shifts are performed computationally and are shifts of pixel values in which each pixel value is indicative of light energy received at a particular photosensor at a specific time. The correlations may be limited to computational shifts of only one pixel for nearest-neighbor correlations, or may be multi-pixel computational shifts. The nearest-neighbor correlation process is often preferred, since it is less computationally complex, with only the original position and eight computational shifts being necessary. Interpolations are then performed to determine angular displacements that are less than a full pixel. Angular displacement of the device about a horizontal axis, i.e. pitch, will result in the arrangement of pixel values of the reference frame being moved upwardly or downwardly. Angular displacement of the device about a vertical axis, i.e. yaw, will result in the pixel value arrangement being moved to the left or to the right. The system detects pitch, yaw and combinations of pitch and yaw. The attitudinal signal that is generated by the system is responsive to the detection of such angular displacements. Optionally, roll may also be considered.
In the application in which the attitudinal signal is generated in order to control a screen cursor, the device preferably includes a transmitter for wireless transmission of a cursor-control signal. For example, the signal may be transmitted via an infrared beam. Changes in the pitch of the hand-holdable device are then translated into vertical movements of the screen cursor, while changes in device yaw will move the screen cursor laterally. In this embodiment, translational movement of the device may also be detected and utilized, so that vertical or horizontal movement of the device translates to a corresponding vertical or horizontal movement of the screen cursor.
One concern in the implementation of the method and system is the effect of the phenomena known in the lens design as curvilinear distortions. Curvilinear distortions are also referred to as pin-cushion, barrel, and perspective distortions. Rectilinear detail is compressed at the outer edges of the field by such distortion. Curvilinear distortion is particularly pronounced in simple lenses with wide fields of view, such as the lens contemplated for use with the present invention. In the invention, the field of view is preferably approximately 64xc2x0, so that curvilinear distortions will inevitably occur.
In the preferred embodiment, the photosensors of the array vary dimensionally in order to define an array that is curvilinear, i.e., includes an arcuate outer edge. The curvilinear array is dimensioned to compensate for the curvilinear distortion introduced by the lens system. The imaging by the optics is evaluated to characterize the curvilinear distortion, with the array then being patterned to offset the distortion. In this manner, the arrangement of the photosensor array and the optics greatly reduces adverse effects of curvilinear distortion.
An advantage of the invention is that device attitude may be tracked in a reliable and cost-efficient manner. For those applications in which the array-bearing device is a hand-holdable device, control of a screen cursor or the like is economically achieved without a premium on dexterity. Moreover, the device does not require operation on a suitable surface.


A heating assembly (36) for heating a cathode (38) of an electron gun (30) of an exposure apparatus (10) includes a radiation source (42) and a beam shaper (44). The radiation source (42) generates a source beam (46). The beam shaper (44) receives the source beam (46) and selectively shapes the source beam (46) into a shaped beam (48) that is directed to the cathode (38). In certain embodiments, the beam shaper (44) can readily change the shape and intensity profile of the shaped beam (48) to achieve a desired electron beam (32) from the electron gun (30). In one embodiment, the radiation source (42) generates a pulsed source beam (46).

Electron beam lithography systems have been used for semiconductor processing for many years. Their application has been somewhat limited however. While electron beam systems can have unsurpassed resolution, their speed of exposing patterns on wafers has historically been inferior to that of other lithography tools, such as optical lithography steppers and scanners. This results in low throughput of exposed product.
Recently, electron beam projection lithography exposure systems have been developed which are expected to offer greatly enhanced throughput. These systems direct a relatively large area electron beam onto a portion ("subfield") of a reticle containing the pattern associated with a specific process step for a semiconductor device. The electron beam transmitted through the reticle is projected onto a wafer where it forms a demagnified image of the illuminated part of the reticle. The reticle and wafer are mounted on precision high speed stages. By a combination of stage movement and electromagnetic deflection of the electron beam, the entire pattern of the reticle is sequentially transferred to the wafer where it exposes an electron sensitive resist. After exposure, the resist on the wafer is developed, and regions of the resist exposed by the electrons are removed, for a positive type resist; or regions of the resist not exposed by the electrons are removed, for a negative type resist. The remaining resist forms a stencil mask, with which the mask features can be transferred into the wafer by etching or deposition processes.
Throughput is enhanced with these electron beam projection lithography exposure systems because all features of the illuminated part of the reticle are transferred to the wafer simultaneously. Past electron beam lithography systems typically transferred the device pattern to the wafer sequentially, with each exposure step transferring at most a few simple geometrical shapes. Throughput in electron beam lithography systems can also be limited by Coulomb interactions between the electrons in the beam. The electric charge carried by the electrons results in repulsive forces which can defocus and blur the image at the wafer. This puts an upper limit on the maximum beam current the electron beam lithography system can effectively operate at, and this in turn limits the useful throughput of the lithography system. However, several features of electron beam projection lithography systems serve to mitigate this situation, allowing higher beam currents, and correspondingly higher throughputs. For example, by increasing the size of the beam illuminating the reticle, for a given beam current, the current density in the beam is reduced. This reduces the effect of the Coulomb interactions. Also, increasing the numerical aperture, i.e. increasing the electron beam half angle, will also reduce Coulomb interaction effects. However, there is an upper limit to the magnitude of the numerical aperture, because geometrical aberrations, which can blur the image at the wafer, increase rapidly with the numerical aperture.
Currently, an additional requirement of electron beam projection lithography systems is that the intensity of the electron beam be uniform, so that all features are exposed in the resist under the same conditions. If the beam is non-uniform, the dimensions of the features in the developed resist may not be faithfully rendered, and some small features may not even be reproduced. To avoid this situation electron beam uniformities of about 1% or better are required at the reticle.
Furthermore, the total electron charge density (the "dose") delivered to an illuminated region of the wafer must be controlled rigorously, so that the electron sensitive resist is properly exposed. If the dose is not carefully controlled, the dimensions of the features in the developed resist may not be faithfully rendered, and some small features may not even be reproduced. The dose is normally controlled by carefully timing the exposure of the illuminated region of the wafer. Therefore, the electron beam current from the gun must be constant in time.
The desired large subfield and numerical aperture of electron beam projection lithography systems mean that the electron beam emittance is much greater than in conventional electron beam lithography systems, where emittance is defined as the product of beam size and angular half-width of the angular distribution of the electrons. In the absence of apertures, which can remove part of the beam, or electron optical subsystems which change the beam energy, emittance is a fundamental property of the electron optical system. Thus, electron beam projection lithography systems can require an electron source, or gun, which also possesses high emittance.
One way of obtaining high-emittance from the electron gun is to use a large heated cathode that emits electrons over a relatively large area. For example, if the subfield at the wafer in an electron beam projection lithography system is 0.25 mm, and the numerical aperture is 8 mrad, the emittance as defined above is 2 mm-mrad. This is several orders of magnitude larger than the emittance of conventional electron beam lithography systems. At the cathode of the electron gun, the half angle of the electrons accelerated out of the gun is given approximately by the ratio of the electron's transverse momentum to its axial momentum. The transverse momentum is related to the thermal energy the electron acquires from the heated cathode, while the axial momentum is related to the beam energy imparted to the electron by the gun. If the accelerating voltage of the gun is V and the cathode temperature is T, then the electron beam half angle is equal to approximately (kT/eV)1/2, where k is Boltzmann's constant and e is the electron charge. For an accelerating voltage of 100 kV and a cathode temperature of 2000° K, the beam half angle is roughly 1 mrad. Thus, the emittance requirement calls for a minimum cathode size of approximately 2 mm. However, in order to meet the uniformity requirement, a very uniform electric field to extract the electrons is needed at the cathode, so to avoid perturbing edge field effects the cathode may need to be several times larger in reality. Also a planar cathode is desirable.
Electron emission from the cathode can be limited by the cathode temperature ("temperature limited operation") or by the accumulation of an electron cloud in front of the cathode, which partially shields the cathode from the accelerating electric field which extracts the electrons into the beam ("space charge limited operation"). Since the electron cloud distorts the electric field, uniform extraction of beam over the emitting part of the cathode will be difficult. Thus, temperature limited operation may be preferred. This puts some constraints on the cathode properties.
The current density j of electrons emitted from a heated cathode is given to a good approximation by the Richardson-Dushman equation,j=AT2exp[−eφ/kT],  (Eq. 1)where A is a constant, and φ is the work function of the material. The work function typically varies with the material's crystalline properties, such as the crystalline orientation at the cathode surface. Thus, the beam uniformity basically requires that the cathode be a single crystal, so that φ is constant. In addition, the temperature of the cathode must be very uniform. For example, for a cathode work function of φ=4 V, a beam uniformity of approximately 1% requires the cathode temperature to be controlled to within approximately 1° K at a cathode temperature of approximately 2000° K.
One method for heating the cathode includes using a heated filament located near the cathode. The filament serves as a source of electron bombardment to heat the cathode to incandescence. Another method includes heating an intermediate cathode with a filament, which then heats the real cathode primarily by radiation.
These methods have provided some success, but they also suffer from certain disadvantages. For example, with a filament, it is difficult to control the area and uniformity of the heating of the cathode. This makes it difficult to obtain temperature uniformity of the cathode.
Additionally, any variations in the local properties of the cathode, such as a variation in the work function of the cathode, can influence electron emission. Also, variations in the thermal emissivity across the cathode surface may create variations in cathode temperature, which will affect the local electron current density. With a filament, there is no way to locally adjust the temperature at different regions of the cathode to compensate for the variation in the work function or emissivity. The heating filament also increases the size and complexity of the electron gun, and the heat generated by the filament adds substantially to the heating within the electron gun, which must be controlled typically with a fluid cooling.
Moreover, a typical filament has a finite lifetime, and must be replaced periodically. During filament replacement, the gun chamber must be opened and the internal components of the electron gun are exposed to atmospheric pressure. Further, the filament heating current and its voltage bias relative to the cathode is controlled by a power supply, which must be biased relative to ground at the cathode voltage. Because the exposure apparatus can operate at high voltages, this biasing has significant impact on the power supply design. At the same time, the power supply to the filament must be stable and noise free, to avoid perturbing the electron beam emitted from the cathode.
Additionally, precision heating of the cathode can be difficult when relatively small incremental amounts of heat need to be added to maintain and/or adjust the temperature of the cathode.
In light of the above, there is a need for a heating assembly that provides substantially uniform heating of the cathode. Further, there is a need for a heating assembly that provides precise heating of the cathode or other object. Still further, there is a need for a heating assembly that minimizes the cooling requirements within the electron gun chamber. Additionally, there is a need for a gun assembly that provides improved electron beam uniformity and stability. Still, there is a need for a gun assembly that is relatively compact, simple, and cost effective to manufacture, assemble and use.

Radiantly heated cathode for an electron gun and heating assembly


An iridium-based alloy which has L12-type intermetallic compounds dispersedly precipitated therein and has a basic composition including, in terms of mass proportion, 0.1 to 9.0% Al, 1.0 to 45% W, and Ir as the remainder. The component system containing 0.1 to 1.5% Al has L12-type intermetallic compounds dispersedly precipitated therein. The component system containing 1.5 to 9.0%, excluding 1.5%, Al has L12-type and B2-type intermetallic compounds dispersedly precipitated therein. Part of the Ir may be replaced with an element (X) (Co, Ni, Fe, Cr, Rh, Re, Pd, Pt, or Ru) and part of the Al and W may be replaced with an element (Z) (Ni, Ti, Nb, Zr, V, Ta, Hf, or Mo). The iridium-based alloy, which contains L12-type intermetallic compounds [1r3(Al,W) and [(Ir, X)3(Al, W, Z)] dispersedly precipitated therein, has a high melting point. The lattice constant mismatch between the L12-type intermetallic compounds, i.e., [Ir3 (Al, W)] and [(Ir, X)3(Al, W, Z)], and the matrix is small and, hence, the iridium-based alloy is excellent in high-temperature strength and structural stability.

With reference to gas turbine members, engine members for aircraft, chemical plant materials, engine members for automobile such as turbocharger rotors, and high temperature furnace members, the strength is needed under a high temperature environment and an excellent oxidation resistance is sometimes required. A nickel-based alloy and cobalt-based alloy have been used for such a high-temperature application.
Many of the nickel-based alloys are strengthened by the formation of γ′-phase [Ni3(Al,Ti)] having an L12 structure. The γ′-phase gives excellent high temperature strength and high temperature creep characteristics because it has an inverse temperature dependence in which the strength becomes higher with rising temperature. The γ-phase becomes the nickel-based alloy suitable for heat-resistant applications such as rotor blades for gas turbine and turbine discs. On the other hand, the cobalt-based alloy is formed by using the solid solution strengthening and the precipitation strengthening of carbide. The system containing a large amount of chromium is excellent in corrosion resistance and oxidation resistance, and further has good wear resistance properties. Thus, it is used as a member, for example, a stator vane and a combustor.
Recently, the improvement of thermal efficiency in various heat engines is strongly required in order to improve fuel efficiencies and reduce the effects on the environment. The heat resistance required for heat engine components has been extremely demanding. For that reason, the development of a novel heat-resistant material as an alternative to the conventional nickel- or cobalt-based alloys has been examined.
With reference to novel heat-resistant alloys, many research reports have so far been published. In recent years, noble-metal materials such as Ir system and Pt system have been attracting a lot of attention (Nonpatent document 1). Both Ir and Pt exhibit good oxidation resistance, and further there is a report that an intermetallic compound such as Ir3Nb having the L12-structure which is the same as that of the γ′-phase of nickel-based alloy is used as a strengthening phase. (Patent document 2)
Nonpatent document 1: JOM, 56 (9), 2004, pp. 34-39
Patent document 2: JP-A 2001-303152

Iridium-based alloy with high heat resistance and high strength and process for producing the same


A disk drive apparatus includes a spindle for engagement with a central hole of a disk hub of a magnetic disk, a rotary member fixed to the spindle, a chucking magnet provided on the rotary member for attracting the disk hub, and a chucking lever pivotally provided on the rotary member which comes at its one end into engagement with a drive hole formed in the disk hub to rotate the disk. When the chucking lever is not chucking the disk, the chucking lever is pivotal about its pivot support point within a given angle, but its movement in the axial direction of the spindle is prevented. The pivot support point section is provided with a disengagement preventive lever which acts in relation to the rotary member to prevent the chucking lever from disengaging from the rotary member.

1. Field of the Invention
This invention relates to a disk drive apparatus for recording and reproducing information in and out of a floppy disk or the like, and more particularly, to a disk driving motor and chucking mechanism for a disk drive apparatus.
2. Description of Related Art
A disk driving motor assembly generally includes a disk chucking mechanism, and rotates a disk (held on a rotary member of the motor assembly by the chucking mechanism) together with the rotary member. Disk chucking mechanisms have been proposed in various forms. See, for example, Japanese Laid-Open Utility Model No. 61-52351.
FIGS. 11-14 show one such conventional disk driving motor assembly including a chucking mechanism. FIG. 11 is a vertical sectional view showing an example of a conventional disk driving motor assembly including a chucking mechanism. FIG. 12 is an overhead plan view showing the disk chucking mechanism. FIG. 13 is a bottom view of the disk chucking mechanism FIG. 14 is a schematic sectional view showing a drive pin section of the disk chucking mechanism.
In these drawings, 501 is a disk, 502 is a disk hub, and 503 is a spindle of the disk driving motor. A chucking lever 508 is pivotally attached, via a support point 516, to a rotary member 504, which is rotatable together with the spindle 503. A spring 514 is provided at support point 506 to urge a drive pin 505 attached to the chucking lever 508 in the axial direction of the drive pin. Another spring 515 (see FIG. 12) is provided between rotary member 504 and Chucking lever 508 to exert an urging force on lever 508 in the circumferential direction of the motor.
When the disk hub 502 is to be chucked (e.g., when it is initially set in place), the chucking lever 508 is pivoted at the support point 516 because one end of it is pushed downwardly by the disk hub 502 as shown in FIG. 14 with the result being that the chucking lever 508 deflects in the direction of the arrow r. Once spindle 503 (and thus rotary member 504 and chucking lever 508) are rotated, disk hub 502 continues to press the one end of lever 508 downward until a drive hole 502b formed in the disk hub 502 (in offset relation to the center thereof) comes into alignment with the drive pin 505 (see FIG. 11).
When a rotor 511 of a spindle motor 510, which is attached to one end of the spindle 503 (as shown in FIG. 11) begins rotating, the drive pin 505 also rotates together with the spindle 503. When the drive hole 502b comes into alignment with the drive pin 505, the drive pin 505 is urged into the drive hole 502b in disk hub 502 by virtue of the pushing force of spring 514.
Consequently, because of the positional relationship between the drive pin 505 and the support point 516, rotation of spindle 503 causes drive pin 505 to exert a force in the direction of the arrow s as shown in FIG. 12 to cause rotation of disk hub 502. Among these forces, the force in the direction of the arrow s acts to press two points along the inner edge of a central hole 502a of the disk hub 502 against the spindle 503, so that the disk hub 502 is rotated while also being centered.
As shown in FIG. 11, a first magnetic head 512 for recording and reproducing an information signal into and out of the disk 501 is disposed on a first carriage 517 between a frame 513 of the spindle motor 510 and the disk 501. A second magnetic head 507 is also provided to engage an opposite side of disk 501.
In the foregoing conventional configuration, however, it is difficult to decrease the thickness of the overall disk drive apparatus because its thickness is determined by the rotor 511 of the spindle motor 510, first carriage 517, first magnetic head 512, the space required for the disk chucking mechanism, etc.
One limitation in reducing the thickness of the disk drive apparatus is caused by the need to provide sufficient space below the drive pin 505 so that the drive pin 505 may retract in the direction of the arrow r as shown in FIG. 14 when the drive pin 505 is pushed by the disk hub 502 (before the disk hub 502 is chucked).
Further, to attach the rotary member of the rotor of the disk driving motor to the spindle, conventionally, as shown in FIG. 11, the rotary member 504 is tightly fitted to the spindle 503 using a bushing 518. Additionally, the rotor 511 is press-fitted to the spindle 503 by forming a cylindrical boss portion 511a integrally with the rotor. As another alternative, shown in FIG. 15, a rotor 521 is fitted to a bushing 522 which is in turn press-fitted to a spindle 523. In FIG. 15, 524 is a drive magnet, 525 is a drive coil, 526 is a motor base, 527 is a circuit board, and 528 is a bearing fitted to the motor base 526.
In the foregoing conventional configurations, however, in order to reduce the swinging (wobble) of the rotary member, or of the rotor relative to the spindle, the fitting section between the spindle and the boss portion 511a or the bushing 518 or 522 must have a certain axial length, this also making it difficult to decrease the thickness of the disk drive apparatus.

Disk driving motor and chucking mechanism for disk drive apparatus


The present invention relates to an improved level wind arm for a winch drum assembly, and a winch drum assembly incorporating such a level wind arm. The level wind arm includes a cross member adapted to bias against an outwardly extending portion of rope, the cross member being concave so that more force is required for the rope spindle associated with the cross member to “climb” the slope of the cross member, causing a momentary pause in motion of the spindle after it reaches the end of wind stroke. This momentary pause allows for rope being wound onto the drum to rise up the end wall of the drum to create a new layer which is aligned and consistent with the layer below, without causing gaps in the rope or other circumstances which could lead to the rope accumulating at any one point, or becoming tangled. The present invention also includes means of ensuring that tension is maintained in the rope, and that the rope does not jump off the reel and, for example, into the clutch mechanism.

It is to be understood that reference to a winch reel herein is the typically cylindrical portion of the winch drum assembly about which rope or other similar rope-like material is wound. Further, although the present invention relates generally to boat winches, it should not be limited to such usage. For example, the winch assembly could equally well be used in other similar applications which require the level winding of a rope onto a winch reel. It is to be still further understood that any use of the word "rope" herein may incorporate within its meaning, chains, wire, cord, cables and any other rope-like material which could be wound around the reel.
Winches are well known devices used on boats for raising and descending anchors. The anchor is connected to a rope or chain which is wound around a reel portion of a winch drum, which is typically powered by a motor for raising and/or descending the anchor. The winch drum is usually positioned a short distance rearward from the front of the boat and the rope is guided by rollers typically positioned on the front deck.
A problem with existing boat winches is that during raising of the anchor, the rope does not level wind, that is, it tends to accumulate at the centre of the winch drum or climb up the opposed side walls of the drum. Accumulation of the rope may result in jerky movement during descent of the anchor, damage to the rope, and in some instances may even prevent the anchor from descending due to excessive tangling. In assemblies where the winch drum rotates through the reduction gearing of the motor, such jerky movements during descent may result in damage to the motor and other parts of the assembly.
In addition, there may be circumstances, particularly in winch drums which have the capacity to free fall, in which proper contact between the rope and drum reel is not achieved, presenting a further situation for damage to the rope and snarling or tangling of the same.
The present inventor is the owner of Australian Letters Patent No. 2007202072 relating to a level wind arm associated with a winch drum assembly which overcomes at least some of the abovementioned problems, and is incorporated by reference herein. The level wind arm includes a cross member which extends substantially parallel to the axle of the winch drum. The spindle is rotatable about the cross member to accommodate forward and backward movement of the rope, and also slideable along the cross member to allow for movement of the rope as it is wound or unwound from the drum.
The cross member is biased and exerts a downward pressure (or upward pressure if the rope extends above the spindle) on the rope a short distance from the drum to ensure that rope is wound or unwound about the drum under tension, and in a level and controlled manner. For a more detailed description of this prior art level wind arm, the reader is referred to the detailed description below in relation to FIGS. 1 and 2 which illustrate the prior art level wind arm.
Although this level wind arm has proven to be effective, a problem has been identified by the present inventor when rope is being wound onto the drum. By the time the rope approaches the end of the reel, and rises up to form a new layer above, the spindle has already started its journey back along the cross member. This causes the new layer of rope to lose consistency with the layer below, and hence gaps can form adjacent the ends of the reel. Once again, this can result in tangling and accumulation. When more rope is wound and further layers are formed, this problem is exacerbated.
It is therefore an object of the present invention to overcome at least some of the aforementioned problems or to provide the public with a useful alternative.


A bilinear decimator converts an input data sequence representing a high resolution image formed by N horizontal pixel lines to an output data sequence representing a lower resolution image formed by P horizontal pixel lines where N>P. The decimation ratio P/N can be any rational fraction. When the decimation ratio reduces to the form 1-(1/n), the decimator computes the each output sequence data value as a simple weighted average of pixel data values for two vertically adjacent high resolution image pixels. When the decimation ratio is other than of the form 1-(1/n), the decimator adds additional terms to the computation of output pixel data values when necessary to compensate for aliasing errors.

1. Field of the Invention
The present invention relates in general to a bilinear decimator for reducing the vertical resolution of a pixel-based image and in particular to a decimator which compensates for aliasing errors.
2. Description of Related Art
An image formed by a set of N parallel lines of L pixels each may be represented by a matrix of pixel data values. Each pixel data value X(n,h) represents a visual characteristic (such as intensity or chroma) of the lth pixel of the nth line of the image. Since various standard video formats have differing numbers of lines, a pixel data matrix suitable for one video format may not be suitable for another. For example one computer video standard employs 768 lines and one television video format employs 400 lines. Although an image on the television may be the same size as an image on the computer screen, it has lower resolution in the vertical direction.
It is sometimes desirable to display image on one video system in response to a pixel data matrix generated by another. One of the problems associated with doing that is adjusting the size of the data matrix representing the image to match the standard of the video system that is to display the image. For example, in order to convert a pixel data matrix having 786 rows of data (one for each line of the computer video image) to a pixel data matrix having 400 rows of data (one for each line of the television image) we have to reduce the number of rows of data in the matrix. One method of doing that is simply to throw out the extra 386 rows of data. Depending on which rows of data we throw out, this would have the effect of clipping a part of the image when it is displayed. To retain some semblance of the full image on the television screen we could remove (decimate) rows of data in an distributed manner so that every second or third line of the image would be remove. However such an image would somewhat distorted because all of the information contained in decimated lines would be lost and the information contained in the retained lines would be over represented in the television image.
For example, suppose a high resolution image produces a certain shade of gray in an area of the image by vertically alternating black and white pixels. If we reduce resolution of the image, for example, by 50% by removing every other line of the image, the gray area in the lower resolution image will appear either all white or all black. This error condition arises because the decimation pattern matches a pixel pattern in the image. Such an error condition is called "aliasing".
U.S. Pat. No. 5,469,222 issued Nov. 21, 1995 to Sprague discloses a decimating filter for lowering the vertical resolution of an image through a process of interpolation. If we superimpose high and low vertical resolution versions of the same image, each pixel of the lower resolution image will fall between vertically adjacent pixels of the higher resolution image. Sprague's filter computes the value of each pixel of the lower resolution image as a weighted sum of the two vertically adjacent pixels of the higher resolution image. The weights are inversely proportional the distance between the output pixel and the adjacent pixels of the input image. Thus for example when reducing the resolution of an image by 50%, instead of throwing out every other pixel line, Sprague's filter produces one output image line for each pair of input image lines, where the intensity or color of a pixel of the output image line is the average intensity or color of vertically adjacent pixels of the two input lines. Since all of the data of the high resolution image has an equal influence on the low resolution image, the lower resolution image is less subject to aliasing errors than if it were produced by simply throwing out every other line of the high resolution image.
The decimation ratio P/N of a filter is the number (P) of lines in the low resolution image divided by the total number of lines (N) of the high resolution image. Sprague's filter employs fixed weighting factors for a given decimation ratio. That means that the relative position of each pixel of the output image is fixed in relation to its vertically adjacent neighbors and does not change from line to line. This is only true for decimation ratios that reduce to the form 1--(1/n) where n is an integer. Thus Sprague's decimator can decimate by a factor of 1/2, 3/4, 7/8 . . . 1--(1/n). It cannot, for example, turn a 768 line image into a 400 line image because it is not capable of producing a decimation ratio of 368/768 (25/48).
U.S. Pat. No. 5,253,041 issued Oct. 12, 1993 to Wine et al, U.S. Pat. No. 4,204,227 issued May 20, 1980 to Gurley, and U.S. Pat. No. 5,159,451 issued Oct. 27, 1992 to Faroudja et al all disclose decimators which use fixed weighting factors for computing pixel values and are thus restricted to decimation ratios of the form 1--(1/n).
U.S. Pat. No. 5,019,904 issued May 28, 1991 to Campbell discloses a decimating filter which uses a lookup table to provide weighting factors that are functions of relative position of an output image pixels with respect to nearby pixels of the input image. Thus a pixel in any given line of the lower resolution output image is not restricted to a particular position with respect to vertically adjacent pixels of the higher resolution input image. Lacking such restriction, Campbell's weighting factor lookup table can be programmed to provide any vertical decimation ratio of the form P/N where P and N are integers. Thus Campbell's system is capable of implementing the 368/768 decimation ratio needed to lower the vertical resolution of the 768 line computer image to the 400 lines of television image.
To further reduce the likelihood of aliasing errors, Campbell's system uses data from the six vertically nearest pixels of the high resolution image, rather than two. Thus each output pixel data value is a weighted sum of contributions from six vertically adjacent pixels of the input image. The two high resolution image pixels nearest the low resolution image pixel are given more weight the remaining four. This reduces aliasing errors. One problem with Campbell's decimator is its size and cost. With six weighting factors, Campbell's system requires six multipliers. Multipliers require a lot space on an integrated circuit and are therefore expensive.
All prior art decimating systems which compute output pixel values as weighted combinations of values of N vertically adjacent input pixels require the use of at least N multipliers in order to apply the weights to the input pixels. Some system employ even more than N multipliers. U.S. Pat. No. 5,268,751 issued Dec. 7, 1993 to Geiger et al describes a polyphase FIR filter apparently employing fifteen fixed coefficients to produce a low resolution pixel as a weighted combination of 4 vertically adjacent high resolution pixels. However since the weighting factors are fixed, Geigher's system is restricted to a decimation ratio of 1--(1/n).
What is needed is a vertical decimation filter providing any desired decimation ratio of the form P/N (where P and N are integers P<N) but which minimizes aliasing errors when necessary without employing excessive numbers of multipliers.

Bilinear decimator with error compensation


A connector spring has a longitudinal spring in one piece according to the following. A first substantially strip-shaped body portion extends along the longitudinal direction of the spring structure. A second body portion extends along and at a distance from the first strip portion and is connected thereto by arcuate connection pieces, which extend from a first side edge of one of the body portions to an adjacent first side edge of the other body portion. First contact tongues are bent from the first side edge of the second body portion in direction towards the other body portion and ends between the planes of the two body portions. Second contact tongues are bent from the first side edge of the first body portion in direction towards the other body portion and ends outside the plane of the second body portion. Third contact tongues are bent from the other side edge of the first body portion in direction outwardly from the two body portions.

The present invention generally relates to a contact spring consisting of a longitudinal spring means, in particular for use in an electro-optic circuit.
An electro-optic circuit is known that comprises optic sender and receiver components for transforming an electric output signal to an outgoing optic signal and for transforming a received optic signal to an electric input signal, respectively, connection means for an opto conductor on which the outgoing and received optic signals are transmitted, a sender for the electric output signal, and a receiver for the electric input signal.
Electro-optic circuits of this kind are used e.g. located on a printed circuit card in a telecommunication switch. Each circuit card carries a plurality of such electro-optic circuits and in the switch one or more cabinets can contain a plurality of shielded card magazines, each of which contains a plurality of such circuit cards. For increasing the insensitivity towards EMC, i.e. electromagnetical disturbance radiation, senders and receivers are conventionally located far in on the card as seen from its edge located at an outer cabinet wall, below denominated card front. On the card front there are seated a number of connection devices for connecting an outer opto conductor to two opto conductors leading to the sender and receiver, respectively, of a corresponding sender/receiver pair. For minimizing the risk for interference between sender and receiver of each sender/receiver pair the sender and the receiver are furthermore located remote from each other on the card.
This distribution of the components of the electro-optic circuit counteracts a striving for a more compact architecture of switches of the just described type, while saving or further improving the insensitiveness for EMC, as well as ESD, i.e. electrostatical discharges.
To take care of this it has turned out to be advantageous that the individual circuit forms a module with an electromagnetically shielded housing that contains the optical sender and receiver components and connection means for the opto conductor, and that a two-sided printed circuit arrangement carries the sender and the receiver located shielded from each other on one side each by means of an electrically conducting shielding that is in connection with the housing for forming three Faraday's cages, one for the sender, one for the receiver and one formed of the housing in its entirety.
In an arrangement of the kind just mentioned it is essential that an intimate contact is maintained between grounding parts of the housing parts by contact means taking up the least possible space.
In EP-124701 there is described a device for contact making of printed circuit cards introduced into brackets, in particular for providing ground connection between a housing and the printed circuit card. It includes a spring clip that surrounds the edge of the printed circuit card and is provided with clawlike extensions which engage the contact surfaces of the printed circuit card and which, when the printed circuit card is inserted in the bracket, is in electric contact with this.
EP-447942 describes a contact rib of metallic material for fitting on the edge of a metallic wall element, in order to provide an interference radiation tight connection. The contact rib has a row of individual contact tongues which are stamped free and outwardly bent from the contact rib plane at a distance from each other, and a row of individual clamp elements distributed at a distance from each other along their lengths.


A robust neural system for robust processing is disclosed for averting unacceptable or disastrous processing performances. This robust neural system either comprises a neural network or comprises a neural network and at least one range transformer. At least one adjustable weight of the robust neural system is a nonlinear weight of the neural work determined in a nonadaptive training of the robust neural system with respect to a nonadaptive risk-sensitive training criterion.. If all the adjustable weights of the robust neural system are nonadaptively adjustable, all these weights are held fixed during the robust neural system's operation. If said neural network is recursive, and the nonadaptive training data used to construct said nonadaptive risk-sensitive training criterion contain data for each of a number of typical values of an environmental parameter, the robust neural system is not only robust but also adaptive to the environmental parameter.. If the robust neural system comprises both nonadaptively and adaptively adjustable weights, these adaptively adjustable weights are adjusted by an adaptor in the robust neural system during its operation. Such a robust neural system is called a robust adaptive neural system. Two types of adaptor are described.

This invention is concerned with robust processing and robust adaptive processing by artificial neural systems (NSs) to avoid unacceptable or disastrous processing performances. The invention disclosed herein is applicable in a large number of fields including pattern recognition, signal/speech processing, system identification/control, communication, robotics, biomedical electronics, mechanical design, sound/vibration cancellation, economics, geophysics, sonar/radar data processing, oceanography, time series prediction, financial market forecast, etc. An artificial NS is hereinafter referred to as an NS.
One of the major concentrated activities of the past 15 years in the conventional control theory has been the development of the so-called "H.sup..infin. -optimal control theory," which addresses the issue of worst-case controller design for linear plants subject to unknown additive disturbances and plant uncertainties. Many references can be found in B. A. Francis, A Course in H.sup..infin. Control Theory, Springer-Verlag, New York (1987); and T. Basar and P. Bernhard, H.sup..infin. -Optimal Control and Related Minimax Design Problems: A Dynamic Game Approach, 2nd Edition, Birkhauser, Boston, Mass. (1995). Although the idea of worst-case design is a little too conservative, "H.sup..infin. -optimal" has become a synonym to the word "robust" in the control theory community.
Among many interpretations of and alternative approaches to the H.sup..infin. -optimality for robust linear control and filtering are those based on the minimax criteria in dynamic games and the risk-sensitive (or exponential cost) criteria. The risk-sensitive criteria were first proposed in D. H. Jacobson, "Optimal Stochastic Linear Systems with Exponential Performance Criteria and Their Relation to Deterministic Games," IEEE Transactions on Automatic Control, AC-18-2, pp.124-131 (1973) for optimal stochastic linear control. The relationships among the H.sup..infin., the minimax criteria in dynamic games and the risk-sensitive criteria have attracted a great deal of attention in the past few years. Some well-known references are K. Glover and J. C. Doyle "State-Space Formulae for All Stabilizing Controllers That Satisfy an H.sup..infin. Norm Bound and Relations to Risk-Sensitivity," Systems Control Letters, vol. 11, pp. 167-172, (1988); P. Whittle, Risk Sensitive Optimal Control, Wiley, New York (1990); Jason L. Speyer and Chih-Hai Fan and Ravi N. Banavar, "Optimal Stochastic Estimation with Exponential Cost Criteria," Proceedings of the 31st Conference on Decision and Control, IEEE, New York, N.Y. (1992); T. Basar and P. Bernhard, H.sup..infin. -Optimal Control and Related Minimax Design Problems: A Dynamic Game Approach, 2nd Edition, Birkhauser, Boston, Mass. (1995); B. Hassibi and A. H. Sayed and T. Kailath, "H.sup..infin. -Optimality of the LMS Algorithm, IEEE Transactions on Signal Processing, vol. 44, pp. 267-280, (1996). For linear systems, H.sup..infin. -optimal controllers and filters can be derived by minimizing some risk-sensitive criteria. Extending these robust processing results to nonlinear problems by the conventional analytic approach is a topic of current research; e.g., W. H. Fleming and W. M. McEneaney, Risk Sensitive Optimal Control and Differential Games, Stochastic Theory and Adaptive Control, pp.185-197, vol. 184 of Lecture Notes in Control and Information Sciences, Springer Verlag, Berlin (1992); M. R. James and J. S. Baras and R. J. Elliott, "Risk Sensitive Control and Dynamic Games for Partially Observed Discrete-Time Nonlinear Systems," IEEE Transactions on Automatic Control, AC-39(4), pp. 780-792 (1994); John S. Baras and N. S. Patel, "Information State for Robust Control of Set-Value Discrete Time Systems," Proceedings of the 34th Conference on Decision and Control, pp. 2302-2307, New Orleans, La. (1995); and W. Lin and C. I. Byrnes, "H.sub..infin. -Control of Discrete-Time Nonlinear System," IEEE Transactions on Automatic Control, vol. 41, No. 4 (1996). However, certain structures of the mathematical models involved are assumed in these papers, and no systematic conventional method of designing a robust discrete-time processor, that is optimal or near-optimal with respect to a robustness criterion for a general nonlinear operating environment, is available.
Since the neural networks are known to be effective nonlinear processors, let us examine the prior art of neural networks (NNs) for robust processing. There are many good books on NNs and their applications. A good introduction to NNs can be found in R. Hecht-Nielsen, Neurocomputing, Addison-Wesley (1990), J. Hertz, A. Krogh and R. G. Palmer, Introduction to the Theory of Neural Computation, Addison-Wesley (1991), S. Haykin, Neural Networks, Macmillan College Publishing Company (1994), and M. H. Hassoun, Fundamentals of Artificial Neural Networks, MIT Press (1995). Applications of NNs can be found in D. A. White and D. A. Sofge, editors, Handbook of Intelligent Control, Van Nostrand Reinhold (1992), B. Kosko, editor, Neural Networks for Signal Processing, Prentice Hall (1992), D. P. Morgan and C. L. Scofield, Neural Networks and Speech Processing, Kluwer Academic Publishers (1991)), and E. Sanchez-Sinencio and C. Lau, editors, Artificial Neural Networks, IEEE Press (1992). There are also a large number of research articles concerning neural networks, which can be found in journals (e.g., IEEE Transactions on Neural Networks, Neural Networks, and Neural Computation), and in Conference proceedings (e.g., Proceedings of the International Joint Conference on Neural Networks).
Patent documents concerning NNs (neural networks) and their applications are too numerous to list here. Three that seem highly relevant to the present invention are as follows. In U.S. Pat. No.5,003,490 to P. F. Castelaz and D. E. Mills, (1991), a multilayer perceptron with a sigmoid activation function and a tapped delay line for the input is used to classify input waveforms. In U.S. Pat. No. 5,150,323 (1992) to P. F. Castelaz, a multilayer perceptron with a sigmoid activation function and a couple of tapped delay lines for preprocessed inputs is used for in-band separation of a composite signal into its constituent signals. In U.S. Pat. No. 5,408,424 (1995) to James T. Lo, recurrent neural networks are used for optimal filtering.
A neural system (NS) comprising an NN and at least one range transformer is disclosed in U.S. Pat. No. 5,649,065 (1997) to James T. Lo for optimal filtering when the range of the exogenous input process or outward output process of the NS is necessarily large and/or keeps expanding during the operation of the NS.
So far, the main concern in synthesizing an NS, whether it comprises a neural network or a neural network and at least one range transformer, has been a good overall processing performance. However, a good overall processing performance may be accompanied with disastrous or unacceptable processing performances on some individual runs of the NS. The issue of robustness for multilayer perceptrons is considered in B. Hassibi and T. Kailath, "H.sup..infin. Optimal Training Algorithms and their Relation to Backpropagation," Advances in Neural Information Processing Systems, vol. 7, pp. 191-199, edited by G. Tesauro, D. S. Touretzky and T. K. Lee, MIT Press, Cambridge, Mass. (1995). Global H.sup..infin. optimal training algorithms for multilayer perceptrons are derived therein. Unfortunately, the ensuing estimators of the weights of a multilayer perceptron under training are infinite-dimensional, requiring growing memory. Upon a specialization, they reduce to a finite-dimensional, but only locally H.sup..infin. optimal estimator, which is the well-known backpropagation algorithm. The local H.sup..infin. optimality of the backpropagation means that it "minimizes the energy gain from the disturbances to the prediction errors, only if the initial condition is close enough to the true weight vector and if the disturbances are small enough." Besides these results on multilayer perceptrons, the issue of robustness has not been considered for neural networks in the open literature.
In summary, a systematic method, conventional or neural-network, of designing a robust processor, that is optimal or near-optimal with respect to a robustness criterion for a general nonlinear operating environment is greatly desired.


A telephone handset universal connector is used to connect between a phone base having a set of four signal outlets, and a handset having a set of four corresponding signal ports. The telephone handset universal connector includes a universal circuitry and a selection switch. The universal circuitry has an electric output 101 for electrically connecting with the four signal outlets of the phone base and an electric output 102 for electrically connecting with the four signal ports of the handset, wherein the selection circuitry provides twelve connection combinations for selectively connecting between the four signal outlets and the four signal ports. The selection switch is electrically connected with the selection circuitry to selectively switch the selection circuitry within the twelve connection combinations.

1. Field of Invention
The present invention relates to a telephone, and more particularly to a telephone handset universal connector which allows a phone base connecting to a handset in twelve different combinations so as to universalize any handset for use with any phone base.
2. Description of Related Arts
A conventional telephone comprises a phone base and a handset comprising a microphone and a speaker, wherein the phone base is electrically connected with the handset via four connection wires in such a manner that audio signal may be transferred between the phone base and the speaker.
Typically, the phone base comprises four signal ports and the handset comprises four signal outlets wherein the four connection wires are electrically connected between the four signal ports with the four signal outlets respectively. Among the four signal outlets, two of which are connected with the speaker and the remaining two are connected with the microphone. As a matter of conventional art, those two connection wires which are connected with the microphone should be polarized in a predetermined manner such that a correct polarity of electrical signal is inputted to the appropriate signal outlet for driving the microphone to operate. In other words, the positive signal inlet must be connected with the positive signal port, whereas the negative signal inlet must be connected to the negative signal port.
On the other hand, those two connection wires which are connected with the speaker needs not polarizing for the speaker to operate. In other words, irrespective of where the two signal outlet connected to, whether a positive or a negative signal ports on the phone base, the speaker may still operate.
A disadvantage of this kind of conventional telephone is that there is no standard way to connect the connection wires with the signal outlets and the signal ports. As a result, it is up to the manufacturer to determine, perhaps for the sake of technical convenience, which connection wire is to connect which signal port with which signal outlet and their corresponding connection combination.
It is important to point out that this disadvantage causes little problem per se, for a phone base is usually accompanied by a corresponding handset in which all the wire connections are predetermined in a particular manner so that there is no operational difficulty. However, problem arises when one is trying to connect an adjunct amplifier or other electronic devices between the phone body and the headset. In such cases, the polarity of the connection wires may be changed by the additional electronic devices so that the handset becomes inactive.
In other words, the telephone is not equipped to add on other electronic devices not because of substantive incompatibility, but simply for unmatched polarity of the telephone wire between the phone body and the handset. Once the connection combination is set, it cannot be adjusted and as a result, become too inflexible to widen add on applications.


Circuits and methods for compensating for an input-dependent gain error in a buffer and/or amplifier circuit, including applying a dynamic current to the input transistor. Circuits generally include a dynamic current supply coupled to a terminal of the input transistor, the dynamic current supply providing a compensating current. The compensating current can have a magnitude equal to the output impedance of the input transistor times a magnitude of the output voltage. The compensating current can be provided via a current mirror, or directly to a terminal of the input transistor. Methods generally include regulating variations in the current through the input transistor by sinking or sourcing a static current and a dynamic current at a terminal of the input transistor. The dynamic current can be regulated in response to a variation in the input signal.

Some conventional amplifiers or buffers include transistors in common-drain configurations. These buffers, commonly referred to as source followers, are advantageous over other amplifier or buffer circuits because of their ability to operate at high speed. Such buffers also enable circuits that provide an output having a high current drive from an input having a relatively low current drive capability. Source follower circuits are also commonly used as level-shifting circuits, for shifting DC bias points in analog or mixed signal circuitry. As illustrated in FIG. 1, a conventional source follower 100 can include a metal-oxide-semiconductor (MOS) input transistor 110 and a current supply 120 that drives a load 130 at the output of the source follower 100. In some implementations, transistor 110 can be a P-channel MOS (PMOS) transistor having a source terminal coupled to current supply 120 and a drain terminal coupled to a ground potential. An input signal VI is applied to a gate terminal of the input transistor 110, and an output signal VO (driving a load 130) is generated from the source terminal of input transistor 110.
There are numerous non-idealities of a typical source follower circuit. For example, the gain of a typical source follower circuit may be characterized by the following Equation (1):
                                          V            O                                V            I                          =                  1                      1            +                                          g                mb                                            g                m                                      +                          1                                                g                  m                                                                  r                  ds                                                      +                          1                                                g                  m                                                                  r                  o                                                      +                          1                                                g                  m                                                                  R                  L                                                                                (        1        )            where gm, gmb, and rds are the transconductance, the back-gate transconductance, and the source-drain output resistance of the input transistor, respectively, ro is the current source output resistance, and RL is the load resistance. The loss due to the back-gate transconductance can be eliminated by coupling or tying the back gate, or body, of the transistor to the source (thus gmb is zero). However, even assuming ideal conditions (for example, where the current source 120 is ideal and the load 130 is purely capacitive, in which case ro and RL are infinite), the gain is still limited by the source-drain output resistance of the input transistor. Moreover, when the current source output resistance is not infinite, the current through the source-drain terminals of the transistor will be modulated due to voltage swings of the input signal (and thus also of the output signal), causing further gain errors and non-linearities.
A "super" source follower 200 is illustrated in FIG. 2. Source follower 200 reduces the voltage dependent gain error by regulating the current through the input transistor to be nearly constant using a feedback loop. The feedback loop in the source follower 200 includes an N-channel MOS (NMOS) transistor 240 having a drain terminal coupled to the source terminal of the input transistor 210, and a second current source 250 coupled to the drain of the input transistor 210 and the gate of the NMOS transistor 240. The second current source 250 is generally a static current source (i.e., the second current source 250 generally sinks a fixed current). The feedback loop reduces the current source output impedance, thereby improving linearity and also reducing the gain error contribution due to the resistive component of load 230. However, super source follower circuit 200 does not lessen the gain error contribution due to the finite source-drain output resistance of the input transistor 210.
Modern electronics requiring high-bandwidth, high-linearity, and/or low-noise designs challenge the conventional assumption that source followers and super source followers have little effect on the AC performance (for example, gain and frequency response) that is predominately caused by the finite source-drain output resistance of the input transistor.
This "Discussion of the Background" section is provided for background information only. The statements in this "Discussion of the Background" are not an admission that the subject matter disclosed in this "Discussion of the Background" section constitutes prior art to the present disclosure, and no part of this "Discussion of the Background" section may be used as an admission that any part of this application, including this "Discussion of the Background" section, constitutes prior art to the present disclosure.

Source follower with gain compensation, and circuits and methods for source follower gain error compensation


Provision is made for identifying selected pages of a document to be automatically sent for printing to one of two or more printing devices. As an example, specific pages can be flagged for printing on a color device while remaining pages stay in default mode, which could be pre-selected as a particular black and white printing device. Upon submission of the job for printing, black images are automatically sent to the black and white device while color pages are sent to a specified color device. The original job remains intact and particular page level settings remain with the job for future use.

More and more printing is done in color, which is more expensive than printing in black and white. Customers are looking for more cost effective alternatives. One such alternative is to print only selected pages of a document in color while remaining pages are printed in black and white.
Two conventional methods for printing selected pages in color are practiced today: manual and automatic. The manual method creates the entire document, including color pages, assigning page numbers, annotations, etc., and then manually and electronically splits the job into two separate files, one for color printing, one for black and white. Splitting results in three separate versions of the original electronic document that must be maintained along with the original file: the initial combined version, the split-off color-printing portion, and the split-off black and white portion. If a content change is required, all three electronic documents frequently must be re-created from the original file. This method works well, but it is cumbersome and time-consuming. In other words, an initial computer file is separated into to other computer files, one for color and one for black and white.
The automatic method uses an algorithm to analyze the actual image data in order to identify either RGB or CMYK color content. The automatic method sets a threshold level for the color content, and uses its algorithm together with the threshold level to route pages automatically either to a black and white printer or a color printer. This method can be very productive, but the accuracy of the algorithm is limited, resulting in black and white pages being printed on the color device or vice versa. Furthermore, this method requires additional hardware and software which can add significant extra cost. Even when the automatic method works well, the printing process is relatively slow. Where color and black and white print engines are in one machine, one engine is idle while the other is printing. Black and white documents print quicker than color documents. If a machine is tasked with printing both color and black and white, the color prints will consume a substantial amount of time during which the black and white print engine is idle.

Method of programming pages within a document to be printed on different output devices


A method of determining pricing to ensure profitability for performance of a task by a business includes entry of employee data, business costs, job costs and business revenues; calculating a profit index factor from the data entered and providing ways of maximizing profit using the profit index factor as a baseline. The profit index factor is used as a baseline for performing analysis of operation profitability and performance; generating gross profit; and tracking profit on a job-by-job basis. The profit index factor is also used as a baseline for finding out how increasing operational expense will effect pricing; finding out increasing production staff will effect pricing; finding out how decreasing production staff will effect pricing; finding out the real burdened cost of billing one employee hour; and pricing service jobs to achieve or surpass a specific profit per hour target.

1. Field of the Invention
The present invention relates generally to profitability management and more specifically to a method of determining pricing to ensure profitability for a business.
2. Discussion of the Prior Art
It appears no software program exists in the art that provides a profitable selling price based on the operating budget and billable hours of a business. It further appears that no other software program calculates the operating budget for the business, allocates that budget per billable hour, tracks history and adjusts the allocation of the budget per billable hour based on accumulated variance, so as to keep the business on track to achieve a predetermined profit goal. However, there are other programs that offer profit calculations and profit analysis.
Topline's Alpha Wolf subtracts variable costs (parts and labor) from the sale price to calculate gross profit (GP), divides sales by the GP to arrive at a Cost Price Multiple (CPM), and compares the CPM to the target CPM entered in program configuration. It then warns if the sale price does not attain an adequate CPM to meet target. In addition, Alpha Wolf calculates and displays the GP per Billed Hour (BH), but it does not calculate the target GP/BH for the business or use the calculation to make comparison to a target.
Mitchell's OnDemand5 Manager/Manager Plus and RO Writer both offer Net Profit Analysis by calculating GP and additionally calculating business overhead using a fixed percentage of the total order. However, neither program offers complete operating budget calculating, nor do they automatically calculate and adjust for variance based on sales and cost history.
Accordingly, there is a clearly felt need in the art for a method of determining pricing to ensure profitability, which calculates the ratio of GP/BH for a business; calculates the ratio of GP/BH to make a comparison to a target; and calculates operating budget to adjust for variance based on sales and cost history.

Method of determining pricing to ensure profitability


This H.V.A.C. duct cleaning system comprises an air compressor connected to a manifold wherein at least one line is coupled to an air gun with a quick connect device while another line is connected to the duct cleaning system providing a pressurized exhaust to remove debris from the ducts. Fixed lengths of plastic tubing are connected to the air gun and one another by quick connects with the end tubing having an air head to dislodge dirt and other contaminants within the ducts. The duct cleaning system includes a series of filter and blower modules controlled by a variable frequency drive to convert and control power to the various blowers. A primary filter module is connected to the ducts, a main filter module connected to the outlet of the primary filter module or blower and a blower which preferably is a tube axial blower or can be a backwardly inclined centrifugal blower is connected o the outlet of either the primary or main filter module to provide a pressurized exhaust. The modules are mounted on aluminum carts with retractable handles, pneumatic or shock absorbing casters and pneumatic tires for ease of movement.

This invention relates to H.V.A.C. systems and in particular to a system for cleaning H.V.A.C. ducts. It is common knowledge that after ducts have been in use for a number of years, they accumulate dirt, dust, and various other contaminants which could be harmful to the individuals breathing the air from such ducts. Many ducts are never cleaned and others are cleaned quite infrequently be antiquated methods. The "sick" building syndrome is receiving considerable attention and the government is considering drafting clean air standards for buildings. Indoor air has been found to be up to seventy times more polluted than outdoor air according to the EPA. Also, 50% of all illnesses are caused or aggravated by polluted indoor air as reported by the American College of Allergists. A dirty heating, ventilation and air conditioning system is a prime cause of indoor air problems.
Various apparatus do exist for scraping and vacuuming ducts by no particular system has received widespread acceptance. Most ducts ate never cleaned, particularly in households and even where an attempt is made at cleaning, the job is slow, laborious and expensive. In contrast, the present invention proposes a portable system which can be wheeled into position, assembled and put into use in both a commercial and a residential environment. This new system cleans ductwork, more efficiently and at lower cost.