A sight glass assembly for a water heater flame trap and a method of making same is disclosed. A rectangular-shaped sight glass frame casing being comprised of a thin metal plate further comprising a rounded rectangular cut-out window and two metal tabs on opposite sides of the casing acting as a retainer to hold the planar transparent material of the sight window tight to the rectangular-shaped gasket. The metal frame casing of the sight glass assembly attaches to the exterior of the flame trap compartment of the hot water heater by: (a) either inserting the tabs, further comprising metal clips, into the gasket whereby they expand, locking the metal frame casing in place; or in a second embodiment (b) riveting the tabs, now in the shape of a flange, directly to the hot water heater shell. The metal frame casing is formed by a metal stamping procedure that allows for easier and more economic manufacture of the sight glass retainer.

The present invention pertains generally to sight glass assemblies and, more particularly, to low cost modular sight glass assemblies which are suitable for installation where vapor control is required.
Sight glass assemblies are widely used in many different types of machines and vessels to observe internal workings. For many installations, the sight glass window and the surrounding framework must be appropriately engineered to withstand and contain the internal environment. This can require a complex assembly of parts, including bezels with multiple interfacing components, and glass or transparent layers with highly engineered interfaces between the glass and the bezel housing. For example, U.S. Pat. Nos. 3,941,460; 3,977,251; 4,169,309; 4,182,179; 4,206,537; 4,436,375; 4,468,095; 5,210,658 and 5,763,776 all disclose complex sight glass assemblies with heavy machined frame structures secured about a glass piece and attached to a vessel in high pressure or corrosive environments. These types of assemblies are of course costly to produce, assemble and install, and are therefore generally found on specialized industrial equipment, such as chemical and food processing equipment. Because it is critical in these applications to maintain the view path for inspection of internal conditions, these types of highly engineered sight glass assemblies are justified.
In other applications, the environment may be less hostile or corrosive, allowing for a less complex construction. For example, U.S. Pat. No. 5,735,168 discloses a sight glass assembly for use on an animal feeder that does not require access to the interior, but which contains multiple layers and at least four fasteners for attachment to a wall. In other words, the design and construction of a sight glass assembly is highly dependent upon the installation environment.
The development of new type of water heater has created a new application for an effective yet economical sight glass assembly. Until recently water heaters have been manufactured with the pilot light and burner contained in a open air shroud underneath the water tank. This allows flammable vapors to easily come into contact with the open flame of the pilot or burner and cause an uncontrolled explosion or fire. To prevent this, a vapor-controlled flame chamber has been developed for use with a water heater. As described for example by U.S. Pat. No. 6,116,195, an enclosed flame trap assembly for water heaters has an air inlet in the form of a plate with a plurality of ports, each port being sized and shaped to cause air and extraneous fumes to pass through the ports at a velocity higher than the flame velocity of the extraneous fumes, to confine ignition and combustion of extraneous fumes within the combustion chamber. More specifically, the patent describes the exact design of openings or xe2x80x9cportsxe2x80x9d in the air inlet which inhibit flames from ignition of extraneous fumes from exiting the flame trap assembly. This greatly reduces the risk of accidental home fires caused by flammable vapors coming into contact with the flame of the water heater burner. This innovation has been heralded as a significant safety improvement in water heater home safety by the U.S. Consumer Product Safety Commission. The flame trap assembly however, is otherwise substantially sealed, which interferes with inspection of the pilot and burner flame.
Thus the need is created to incorporate a sight glass into this type of flame trap assembly to enable visual inspection of the burner assembly and operation, particularly with respect to gas flow in the absence of a flame, which could lead to gas poisoning or uncontrolled explosion.
This type of sight glass is primarily subject to heat, rather than pressure. Otherwise, the primary performance criteria (in addition to providing the view path) is to maintain the vapor control integrity of the flame trap assembly. Therefore, a principal objective of the invention is to provide a sight glass assembly which maintains the vapor control function of the flame trap assembly but which is economical for mass production in flame trap equipped water heaters.
The present invention provides novel solutions to these and other aspects of water heater flame control systems, by providing a modular sight glass assembly frame that does not require custom fasteners or fittings, but still creates a sufficient seal and window area. The design is also economical to produce and assemble. In one embodiment the securing tabs allow for the sight glass assembly to be easily snapped into position on the exterior of the flame trap compartment. In another, the sight glass assembly is secured by two rivet-like fasteners, allowing for a more flexible placement and less cutout area in the flame trap assembly compartment wall.
In accordance with one general aspect of the invention, there is provided a sight glass assembly with frame casing having a front face, side walls, an upper wall, a lower wall, an opening in the front face, and securment extensions which extend from at least two of the side walls; a piece of planar transparent material having an outer perimeter dimensioned to fit within the walls of the frame, and to span the opening in the front face, wherein the walls extend over the edges of the transparent material; a generally planar gasket having an outer perimeter greater than an outer perimeter of the casing, and an opening having a perimeter less than the outer perimeter of the transparent material wherein the securement extensions are configured to engage with a structure having an opening generally aligned with the openings in the gasket and the frame to provide a sight glass through the opening in the structure.
In accordance with another general aspect of the invention, there is provided a modular sealed sight glass assembly adapted for attachment to a wall section to provide a sealed view path, including a frame having a planar face wall and an opening in the face wall defining a viewing port; framing walls extending generally perpendicularly from a perimeter of the face wall, at least one of the framing walls further comprising a securement extension; a piece of transparent material dimensioned to fit within the framing walls and against the face wall; a gasket having an outer perimeter greater than the face wall of the frame, and an internal opening having a perimeter less than a perimeter of the piece of transparent material, the internal opening of the gasket being generally aligned with the opening in the face wall, and the gasket being positioned against the transparent material opposite to the face wall of the frame.
And in accordance with another aspect of the invention, there is provided a sight glass assembly in combination with a combustion chamber, the combustion chamber having a shroud with at least one wall and an opening through a cross-section of the shroud wall, a sight glass frame having a face plate with an opening and perimeter walls which extend perpendicularly from the face plate, a planar transparent piece which fits within the perimeter walls of the frame and against the face plate, and a gasket with an opening which corresponds to the opening in the face plate and the opening in the shroud wall and which extends at least partially beyond a perimeter of the face plate, the gasket being positioned against the shroud wall and about the opening in the shroud wall, and the transparent material and face plate being positioned over the gasket and attached to the shroud wall.
These and other aspects of the invention are herein described with reference to the accompanying Figures representative of several of many possible embodiments of the principles and concepts of the invention.


A casing includes a solid sleeve and a split sleeve in combination to provide a connection between a fiber stub and a ferrule containing an optical fiber. The arrangement prevents wiggle of the ferrule, and also does so without the tight tolerances that would otherwise be required in solid sleeve systems.

Pluggable fiber optic transceiver modules having form factors with names such as Xenpak, X2, XFP and SFP use receptacles to connect the optical subassemblies with optical fiber cables for optical signal transmission into and out of the transceiver. To align the connector of the optical fiber with the fiber stub inside the receptacle for better optical signal transmission, two styles of centering bores are usually used: solid and split-sleeve. We refer to these types of centering bores as solid sleeves and split sleeves, respectively. These centering bores are configured to have a fiber stub at one longitudinal side, and a ferrule with an optical fiber attached thereto at the other side.
An example of such a solid sleeve is shown in FIG. 1. The solid bore sleeve 101 is completely rotationally symmetrical and constructed of a rigid ceramic material, typically Zirconia. Due to fabrication tolerances the diameter of the solid sleeve can not be made exact, or at the very least, it is difficult to do so. Therefore, the inner diameter of the sleeve 101 must be made slightly larger than the outer diameter of the connector ferrule to be inserted (not shown). This gap can be up to 2 μm.
This configuration is not able to give a very stable and repeatable optical connection for the optical fiber connector with the fiber stub 102, because the connector ferrule can move with the sleeve such that the center of the optical fiber in the ferrule may become off center with respect to the center of the fiber in the optical stub 102. This "offset" changes the light power transmitted, causing degraded performance and potential errors.
A split sleeve bore 201 as shown in FIG. 2, in contrast, is separated lengthwise along the cylindrical wall by a slot 202, and is made with an inner diameter slightly smaller than the diameter of the connector ferrule. This split sleeve structure is more flexible and is therefore able to enlarge its inner diameter slightly to accommodate the diameters of the fiber stub and ferrule. When the ferrule (not show) is inserted, the split sleeve can expand and then clamp down on the inserted ferrule, thereby accurately centering the connector ferrule with the fiber stub inside the receptacle.
However, when a side load is applied to connector ferrule, the split sleeve can expand and thereby allow a large tilt or even an offset of the connector ferrule which will cause a misalignment between the two fiber cores and hence induce optical power variations in the connection. Essentially, to achieve the improved ability of the split sleeve over the solid sleeve, one must sacrifice the overall stability of the sleeve itself.
One prior art solution to the above problem is a stepped split sleeve. A stepped split sleeve has a variable wall thickness along the length thereof. Using a stepped thickness, the thicker end of the split sleeve bore is able to hold the fiber stub tightly and therefore the expansion of split sleeve only occurs at the thinner end of the bore. In this way, the amount of connector tilt inside the split sleeve bore can be effectively reduced. However, a stepped split sleeve is more difficult to fabricate and hence becomes more expensive than a regular split sleeve bore. Moreover, the stepped sleeve thickness can cause mechanical stress to concentrate around the step area when the split sleeve expands which can cause the split sleeve to crack.
Another method involves press fitting the split sleeve to the fiber stub to tightly couple it and decrease movement. However, mechanical stress can build up around the area where the split sleeve is tightly coupled to the fiber stub, thereby causing the ceramic material to crack. Moreover, press fitting a split sleeve together with fiber stub into the receptacle metal body requires extreme tolerance control of three parts, thereby increasing the cost of the assembly.
Other prior art methods exist, but all fail to provide an economical manner in which to obtain optimum alignment between the ferrule and the fiber stub. It is this issue to which the present invention is largely directed.


An apparatus for use in clamping a structure at its edge, the structure having opposed surfaces, the apparatus comprising a stanchion, a first clamping assembly attached to the stanchion and a second clamping assembly selectively slidably moveable longitudinally along the stanchion, the second clamping assembly including a support plate extending laterally outward in a direction away from the stanchion, the support plate being positioned closely adjacent one of the opposed surfaces of the structure when the structure is clamped between the first and second clamping assemblies.

1. Field of the Invention
The present invention relates to temporary guard rail systems disposed at the peripheral edge of a structure such as an elevated floor slab. More generally, the present invention relates to a clamping apparatus that can be used, inter alia, in the erection of such a temporary guard rail system.
2. Description of the Prior Art
In the construction industry, commercial, industrial and multi-unit residential buildings are typically constructed with a framework of steel girders. The framework for the various floor levels as formed, concrete floor slabs are poured so that the workmen on the project have floor support upon which to perform their task. Since the floor slabs are poured before the building walls are constructed, it is important to create some type of perimeter guard at the edges of the floor slabs to prevent workers from inadvertently falling off the edge of a floor slab without realizing they are near the edge. Additionally, perimeter guard rails, to meet certain governmental standards, have to have a toe board that generally abuts the top surface of the slab so as to prevent tools and construction materials from falling off the edge of the slab onto workers below.
For many years temporary guard rails forming perimeter guards for floor slabs in a multi-story building or the like have been provided by installing temporary stanchions or posts at spaced intervals around the perimeter of an elevated floor slab. The posts or stanchions provide vertical supports to which horizontal guard rails can be attached to form the temporary guard rail around the perimeter of the floor slab.
Typical of systems used in constructing temporary guard rails or other perimeter guard constructions are those disclosed in U.S. Pat. Nos. 3,863,900; 3,995,833; 4,307,824; 5,029,670; 6,585,080; and 6,679,482.
In U.S. Pat. No. 5,560,588 there is disclosed a support for a temporary guard railing that comprises a base adapted to be removably attached to a floor surface, e.g., the surface of a slab, and support walls upstanding from the base and defining between them an inwardly opening socket for receipt of a post. At least one pair of parallel rail guide flanges are adjoined to the base and project laterally outwardly with respect to one of the support walls whereby a rail such as a 2×4 can be received between the rail guide flanges. The support disclosed in U.S. Pat. No. 5,560,588 has found wide-spread success in the construction industry, particularly, in use in forming temporary guard rails around wooden floors, stairs and the like. Further, while the support system disclosed in U.S. Pat. No. 5,560,588 can be employed with concrete slabs, stairs and the like, it suffers from the disadvantage that in such circumstances holes must be drilled into the concrete slab in order to mount the support. This is time consuming and furthermore requires, in many cases, that the drill holes be patched once the temporary guard rail system is removed.
Aside from erecting temporary guard rails along the peripheral edges of floor slabs, stairs and the like, clamp assemblies that can be used to clamp along the peripheral edge of a slab, stairs, or similar structure, have a wide variety of uses in addition to being used in the construction of a temporary guard rail.

Clamping apparatus and apparatus for use in erecting temporary guard rails


In some aspects, the disclosure is directed to signal processing methods and systems for identifying a material on a body of a person using electromagnetic radiation. A radar system may measure a first reflection of radiation incident on a body of a person. The first reflection may be from a surface of the body. The radar system may measure a second reflection of the radiation. The second reflection may be from a first material residing on or proximate to the surface of the body. An analyzer may determine, relative to the first reflection, a delay in the second reflection due to propagation of a portion of the radiation through the first material. The analyzer may determine, based on the delay, at least one of: the first material and a dielectric constant of the first material.

In conventional systems for surveillance and detection purposes, images based on X-ray, conventional cameras, infra-red cameras and other techniques may be employed. These techniques focus on generating an image that profiles a detectable shape, outline and/or movement of an object. These characteristics may be reviewed by a person or processed using machine recognition. However, although characteristics like shapes and outlines may help to detect the presence or suspected presence of an object, manual intervention and follow-up is typically needed to verify the detection, and to test an unknown material for identification or threat potential. The latter may require a different process or means to augment the initial imaging step, such as the use of sniffer dogs or a physical analysis of a sample of the material to identify the material. Such means may be considered intrusive and/or offensive to the subject, and may add significant delay to the overall process of identifying an unknown substance or object.

Signal processing methods and systems for explosive detection and identification using electromagnetic radiation


A coordinate data input device is fabricated by stacking a sensing board having a film provided with a plurality of parallel x-electrodes on its front surface, a plurality of parallel y-electrodes extending perpendicularly to the first electrodes on its back surface, and through holes formed at one end of each electrodes, and a printed wiring board provided with a plurality of through holes at positions corresponding to the through holes formed in the film of the sensing board at the ends of the first and the second electrodes, and a circuitry formed on its back surface, for driving and controlling the first and the second electrodes of the sensing board. Conductive films are formed on the side surfaces of the through holes of the sensing board and those of the printed wiring board so as to electrically connect the first and the second electrodes of the sensing board to the circuitry of the printed wiring board.

The present invention relates to a coordinate data input device of an electrostatic capacity type capable of detecting the position of a point on a screen touched mainly with a finger through the detection of a change in electrostatic capacity, and a method of fabricating such a coordinate data input device.
Recently, a coordinate data input device of an electrostatic capacity type generally referred to as tablet has been put to practical use. An operator is able to enter the x- and the y-coordinate of a point on the screen of the coordinate data input device by touching the point with a finger.
A conventional coordinate data input device has a printed circuit board, a sensing sheet using a rectangular dielectric film as a base film and placed on the printed wiring board, and a flexible wiring board electrically connecting the printed wiring board and the sensing sheet. The dielectric film of the sensing sheet is provided on its front surface with a plurality of parallel x-electrodes extended in parallel to the x-axis. Ends of the x-electrodes on the same side of the dielectric film serve as connecting ends, and a first connector is connected to the connecting ends of the x-electrodes. The dielectric film is provided on its back surface with a plurality of parallel y-electrodes extended in parallel to the y-axis. Ends of the y-electrodes on the same side of the dielectric film serve as connecting ends, and a second connector is connected to the connecting ends of the y-electrodes. The opposite ends of the flexible wiring board are connected to the connectors and the printed wiring boards to electrically connect the electrodes of the sensing sheet to drive circuits and control circuits formed on the printed wiring board.
When an operator's finger is put to an optional position on the sensing sheet, part of lines of electric force extending from the x-electrodes toward the y-electrodes is intercepted by the operator's finger to reduce lines of electric force reaching the y-electrodes, so that the electrostatic capacity changes, and the coordinates of the position touched with the operator's finger can be determined on the basis of an output current produced by the sensing sheet varying according to the variation of the electrostatic capacity.
As mentioned above, in the conventional coordinate data input device of an electrostatic capacity type, the x-electrodes and the y-electrodes formed on the sensing sheet are electrically connected through the connectors and the flexible wiring board to the printed wiring board. Therefore, the thickness of the coordinate data input device is dependent on the relatively great thickness of the connectors attached to the front and the back surface of the sensing sheet. Since the flexible wiring board is expanded toward one side of the sensing sheet and is extended to the printed wiring board, a relatively large space is required to layout the flexible wiring board, which increases the overall external dimensions of the coordinate data input device.

Coordinate data input device and method of fabricating the same


A production line system includes n operational stations L1, L2, L3 . . . Ln. Each operational station includes: m operational devices Dn1, Dn2, Dn3 . . . Dnm in each operational station, and the operational devices used for processing operated products with m specifications, respectively, in which n=1, 2, 3, . . . n and m≧1. An initial terminal of the production line system comprises a signal analyzer and a transport mechanism. The signal analyzer is used for analyzing product information of an operated product and for demanding the transport mechanism to deliver the operated product to a corresponding initial operational station and a corresponding operational device according to the product information The production line system provided can deal with products with more than two different specifications at the same time, and especially can apply to producing a small number of products or an experimental batch of products. The production line system has advantages of saving production time of a small number of products, effectively utilizing devices on the production line, improving production efficiency, and reducing production cost.

1. Field of the Invention
The present invention relates to a production line and a controlling method thereof, and more particularly, to a production line capable of dealing with products with more than two different specifications at the same time and a controlling method thereof.
2. Description of the Prior Art
A production line is a mechanical system in which operating workers or industrial robots are allocated. A production line is also an operational line in which a determined production procedure is finished step by step. The process route and processing laboring ratio of major products or of most of products on the production line determine the number of the mechanical device which is necessary for finishing processing some sorts of products on the production line, the disposition of the mechanical device, the arrangement of the operational place, etc.
The production line system is frequently used in the conventional production industry. However, it is only possible to produce products with the same specification in the same period of time on the same production line. The production line has to be cleared up completely when a small number of products need producing. Besides, a small scale of experimental batches need producing before a large number of products are produced or the manufacturing process is improved. At this time, the production line has to be cleared up completely as well. After the production line is cleared up completely, the production starts, which is a waste of time. Especially, the conventional production line greatly affects capacity and cost of sophisticated and difficult industries such as the TFT-LCD (Thin Film Transistor Liquid Crystal Display) industry. It is harder to control the manufacturing process of the sophisticated and difficult industries, or the abnormality of the manufacturing process of the sophisticated and difficult industries frequently occurs, so engineers often try to produce a small scale of experimental batches before improving the manufacturing process.

Production line system and controlling method thereof

Shenzhen China Star Optoelectronics Technology Co., Ltd.


A flex cable comprises a base film, a first adhesive layer coupled with the base film, and at least two signal traces coupled with the first adhesive layer. The flex cable comprises a second adhesive layer coupled with the signal traces and the first adhesive layer, and a cover film coupled with the second adhesive layer. The flex cable comprises an electrically conductive layer adjacent to the signal traces, and parallel with the base film and the cover film.

Flex circuits are used to electrically couple components together such that relative motion between the components is made possible while maintaining electrical coupling. In a hard disk drive the flex circuit that couples the actuator with the base casting is known as a flex cable.
Expectations and demands continually increase for hard disk drives to store and manipulate larger quantities of data at faster speed. To meet these expectations and demands, the hard disk drive and its components are continually being improved. All electrical components, such as the flex cable are being scrutinized for their electrical characteristics and how their electrical performance can improve a hard disk drive's ability to store and manipulate larger quantities of data at faster speed.

Flex cable and method for lowering flex cable impedance

Hitachi Global Storage Technologies, Netherlands B.V.


A semiconductor encapsulating epoxy resin composition is provided comprising (A) an epoxy resin, (B) a phenolic resin curing agent, (C) a molybdenum compound, (D-i) an organopolysiloxane, (D-ii) an organopolysiloxane cured product, or (D-iii) a block copolymer obtained by reacting an epoxy resin or alkenyl group-bearing epoxy resin with an organohydrogenpolysiloxane, and (E) an inorganic filler. The composition has improved moldability and solder crack resistance while exhibiting high flame retardance despite the absence of halogenated epoxy resins and antimony oxide.

The current mainstream in the semiconductor industry resides in diodes, transistors, ICs, LSIs and VLSIs of the resin encapsulation type. Epoxy resins have superior moldability, adhesion, electrical properties, mechanical properties, and moisture resistance to other thermosetting resins. It is thus a common practice to encapsulate semiconductor devices with epoxy resin compositions. Semiconductor devices are now used in every area of the modern society, for example, in electric appliances and computers. As a guard against accidental fire, the semiconductor encapsulating materials are required to be flame retardant.
Halogenated epoxy resins (typically chlorinated and brominated epoxy resins) combined with antimony trioxide are often blended in epoxy resin compositions in order to enhance flame retardance. This combination of a halogenated epoxy resin with antimony trioxide has great radical-trapping and air-shielding effects in the vapor phase, thus conferring a high fire-retarding effect.
In a high-temperature environment, however, such flame retardants as halides (typically chlorides and bromides) and antimony compounds are decomposed to give rise to chemical reaction at connections between gold wires and aluminum lines. This results in an increased resistance at the connections or even disconnection, inviting malfunction. In addition, the halogenated epoxy resins generate noxious gases during combustion, and antimony trioxide has powder toxicity. Given their negative impact on human health and the environment, it is desirable to entirely exclude these fire retardants from resin compositions.
In view of the above demand, studies have been conducted on the use of hydroxides such as Al(OH)3 and Mg(OH)2 or phosphorus-containing fire retardants in place of halogenated epoxy resins and antimony trioxide. Unfortunately, because of various problems associated with the use of these alternative compounds, such as inferior curability of the resin composition during molding and poor moisture resistance in the cured product, they are not yet ready for practical application.

Semiconductor encapsulating epoxy resin composition and semiconductor device


An improved blast furnace system for producing molten iron incorporating a preheater to heat the cold blast air used to temper the hot blast temperature is disclosed. The improved blast furnace system comprises a blast furnace, a hot blast main for conveying a supply of hot blast to the blast furnace, a plurality of stoves for heating a supply of cold blast and generating the hot blast, a cold blast main for conveying a supply of cold blast to the plurality of stoves, and at least one cold blast preheater for heating a portion of the cold blast, that has been diverted to the preheater, into heated air and the heated air is mixed with the hot blast to temper the hot blast temperature.

In a blast furnace system, a plurality of blast furnace stoves is operated at time-displaced cycles to heat a blast of air used to provide heat for a blast furnace. In each stove, there is a vertical combustion chamber coupled to a burner to inject gas, usually excess blast furnace gas, and air into the bottom portion of the chamber for combustion. Each stove is alternately on gas (being heated by combustion of the blast furnace gas) or on blast (heating the cold blast air). The combustion products are directed by a dome from the top of the combustion chamber into a regenerator through passageways in a filling of refractory checkerbrick to heat the blast of air. The blast of air usually flows through the openings in the checkerbrick countercurrent to the flow of combustion gases.
Generally, the heated air is withdrawn through an opening in the side wall of the combustion chamber. In such a blast furnace stove, the burner is usually arranged to direct the flame horizontally into the bottom of the vertically extending combustion chamber. A water-cooled burner valve opens and closes the passageway from the stove gas burner into the combustion chamber and provides thermal protection for the metal parts of the burner.
Typical blast furnace systems operate continuously for many years. But in many blast furnace systems the blast furnace stoves begin to deteriorate long before the end of the blast furnace campaign itself. Deteriorating blast furnace stoves' heating capacity will diminish and as a result the hot blast air supplied to the blast furnace will not be sufficiently hot for optimal operation of the blast furnace. This deterioration of the stoves require the blast furnace to burn more fuel to compensate for the lower hot blast temperature but after a certain level of deterioration of the stoves, the stoves must be repaired. The refractory work in the stove becomes plugged either from dirt in the blast furnace gas combustion products or falling and crumbling brickwork. The plugging reduces heat transfer surface area. The heat transfer efficiency of combustion flue gas heating the brick as well as the hot refractory heating the cold blast air diminishes as the refractory system becomes plugged. The net result is a lower hot blast temperature. In order to maintain the same production at the blast furnace more fuel must be added to the blast furnace. The fuel can be in the form of additional metallurgical coke with the top solid charging or by fossil fuels that are added near the hot blast tuyeres. The stoves may consume less fuel during heating. But, repairs to a stove generally can be carried out only after the stove is cooled to near ambient temperature, which means that the stove can not be operating. This long interruption to the operation of the stove substantially affects the blast furnace's economical operation.
Thus, an improved blast furnace system is desired.

Preheating cold blast air of a blast furnace for tempering the hot blast temperature


A semiconductor fabrication method comprises providing a structure which includes a semiconductor substrate having a plurality of subsurface layers, the substrate comprising a top surface and the subsurface layers comprising a top subsurface layer below the top surface of the substrate. A protective material is patterned on the top surface of the device and a material removal process is performed to simultaneously form a contact trench and an isolation trench, the material removal process removing at least a portion of the top surface and the top subsurface layer such that the contact trench and the isolation trench are formed within the subsurface layer. An insulator is then formed within the isolation trench and the contact trench is lined with the insulator. The contact trench is then filled with a conductive material such that the conductive material is deposited over the insulator.

1. Field of the Invention
The present invention generally relates to a method of forming both a device isolation structure and a through-BOX (Buried OXide) contact in the same process operation.
2. Description of the Related Art
In silicon-on-insulator technologies it is usually necessary to make device isolation structures as well as a through-BOX contact structures. These are typically created in separate steps.
The embodiments described below form both a device isolation structure and a through-BOX contact in the same process operation to isolate Silicon-On-Insulator (SOI) regions to permit devices to operate at different electrical potentials, facilitating high voltage circuits by connecting devices in series, and reduce parasitic capacitances and improving noise immunity.

Simultaneously formed isolation trench and through-box contact for silicon-on-insulator technology

International Business Machines Corporation


A motor vehicle power transfer unit includes an input portion, an output portion, a non-parallel gear set and a parallel gear set. The input portion is adapted to connect to an output portion of a transmission assembly and the output portion is adapted to connect to an input portion of a rear wheel drive line. The parallel gear set is coupled to the input portion and transfers power to the non-parallel gear set, which is coupled to the output portion. The non-parallel gear set includes a ring gear having a front face with gear teeth formed therein and a rear face having a cavity formed therein. The ring gear is supported within the power transfer unit by a bearing mounted within the cavity.

1. Field of the Invention
The present invention relates to the power train of a motor vehicle. More specifically, the present invention relates to a power transfer unit in the power train for distributing power to the front and rear wheels of the vehicle.
2. Description of the Prior Art
In the past, most automobiles in the United States utilized a rear wheel drive power delivery scheme. In adapting these rear wheel drive schemes into four wheel drive applications, a transfer case was, and often still is, positioned at the output of the transmission assembly. When engaged, the transfer case diverts a portion of the power coming from the transmission assembly from the rear wheels to the front wheels.
Currently in the United States, a significant portion (if not a majority) of new automobiles are front wheel drive based vehicles. In a front wheel drive vehicle, both the engine and the transmission assembly are typically transversely oriented in the vehicle. By positioning the power plant and transmission assembly transversely in the vehicle, more direct coupling of the transmission assembly to the vehicle's transaxle and front wheels can be achieved. In doing so, a front wheel differential is incorporated directly into the transmission assembly itself.
With front wheel drive vehicles themselves becoming a mature market, a recent trend in the automobile industry has been to adapt these front wheel drive schemes for all or four wheel drive applications. This is accomplished by providing a power transfer unit that diverts a portion of the power from the front wheels to a rear wheel drive shaft and subsequently the rear wheels.
While prior power transfer units work sufficiently well for their intended purposes, their construction limits the extent to which their size can be reduced (thereby making the engine bay unavailable for other components). This also limits packaging flexibility of the units themselves. Normally front differentials in transaxles are of the bevel type and require a large amount of axial space along a direction transverse to the vehicle. As the transaxle package grows axially, it interferes with having equal length halfshafts and furthermore steering, suspension, and engine mount/roll restrictor placement.
As a way of maximizing manufacturing resources, it is also desirable to develop automotive products that can be utilized and incorporated across a variety of platforms. When incorporated into a vehicle, the power transfer unit is attached to the output face of the vehicle transmission. It is therefore in close proximity to the engine, the transmission, the steering rack and the exhaust manifold. Additionally, new PZEV catalytic converters are required to be located closer to the exhaust manifold so that they can achieve a quicker "light-off" of the catalyst. These PZEV catalytic converters also tend to be larger and generate higher temperatures than previous non-PZEV catalytic converters. The proximity to the engine, transmission and the other under hood components accordingly limits the size of the power transfer unit. Further, the high temperature of "manicat" catalytic converters and the previously mentioned PZEV catalytic converters means that polymer based products, such as lubricants and seals, need to be placed at as great a distance as possible from the PZEV catalytic converter.
One manner in which the overall size of the power transfer unit can be reduced is to similarly reduce the size of the gears, bearings and shafts of the power transfer unit itself. However, reducing the size of these components limits their overall torque carrying capacity.
An end result of all of the above is a desire for lateral compactness in the design of the power transfer unit. By compacting this lateral size of the power transfer unit, the power transfer unit can be configured as multiplatform assembly, in that the system itself can be designed for the worst case scenario, in other words the minimum lateral width available for a power transfer unit.
In order to achieve the greatest lateral compactness possible, the gears and bearings located inside the power transfer unit need to be located in the most space efficient manner possible. This can result in conflicts in the sizing and shaping of various components of the unit.
It is therefore an object of the present invention to overcome the above and other limitations of the prior art and to provide a more compact power transfer unit, thereby increasing the available packaging space in the motor vehicle's engine bay.


A test circuit tests for defective memory cells in a memory portion of an Embedded DRAM. The Embedded DRAM includes an array of memory cells. The test circuit includes a test mode terminal adapted to receive a test mode signal and a plurality of comparison circuits. Each comparison circuit includes a first input adapted to receive a read data signal and a second input adapted to receive an expect data signal. Each comparison circuit compares the binary values of the read and expect data signals and develops and inactive error signal on an output when the compared signals have the same binary values, and develops an active error signal when the compared signals have different binary values. A storage circuit is coupled to the outputs of the comparison circuits. The storage circuit latches the error signals output by the comparison circuits and sequentially transfers the latched error signals onto a data terminal of the Embedded DRAM. A test control circuit is coupled to the comparison circuits, the test mode termninal, and the storage circuit. The test control circuit operates when the test mode signal is active, to apply data from addressed memory cells respectively on the first inputs of the comparison circuits. The test control circuit also applies respective expect data on the second inputs of the comparison circuits and controls the storage circuit to latch the resulting error signals and thereafter sequentially transfer the latched error signals onto the data terminal. The test circuit may include additional stages of comparison circuits to further compress read test data, as well as additional storage circuits for storing such additional compressed data.

The present invention relates generally to semiconductor memories, and more specifically to a method and circuit for testing an Embedded DRAM including memory and logic circuitry formed in a single integrated circuit.
Advances in the design and fabrication of integrated circuits have resulted in significant decreases in the size of transistors and other components forming such integrated circuits. Accordingly, the density of transistors and other components that may be formed in a semiconductor substrate of a given size has increased dramatically. Such dramatic increases in the density of components have enabled manufacturers to fabricate high capacity memory devices in the same size substrate previously required for much lower capacity devices. Similarly, for microprocessors and other logic circuits, such increased component density has enabled manufacturers to increase functionality by including additional circuitry on the substrate.
In addition to improving functionality and performance of existing types of integrated circuits, increased component density has enabled manufacturers to develop a new type of integrated circuit called an xe2x80x9cEmbedded DRAMxe2x80x9d in which logic circuitry and dynamic random access memory (xe2x80x9cDRAMxe2x80x9d), or other type of memory, are formed in the same integrated circuit. In other words, the logic circuitry may be xe2x80x9cembeddedxe2x80x9d in the DRAM. FIG. 1 is a block diagram of an Embedded DRAM 11 including logic circuitry 13 and a DRAM 15 formed in a semiconductor substrate 17. The logic circuitry 13 may be designed to perform a specific function, or may be more general purpose circuitry, such as a microprocessor performing a variety of different tasks. The logic circuitry 13 is coupled to the DRAM 15 through an address bus 19, internal data bus 21, and control bus 23, and applies address, data, and control signals on these respective busses to transfer data to and from the DRAM 15. The logic circuitry 13 is further coupled to external terminals 25 on which the logic circuitry transfers information to and from external circuits (not shown in FIG. 1) coupled to the Embedded DRAM 11.
In the Embedded DRAM 11, forming the logic circuitry 13 and the DRAM 15 in the same semiconductor substrate 17 yields numerous performance benefits. First, the bandwidth of the DRAM 15 may be substantially increased by increasing the width N of the internal data bus 21, where N may be 128, 256, or 512 bits, or even wider. As understood by one skilled in the art, increasing the width N of the internal data bus 21 increases the bandwidth of the DRAM 15 by enabling more data to be transferred during each access of the DRAM 15. In a conventional DRAM, an external data bus of the DRAM has a width that is limited by a number of factors, including the number of pins that can physically be formed on a package containing the DRAM and noise generated by switching multiple data lines in parallel, as understood by one skilled in the art. In contrast, the internal data bus 21 of the Embedded DRAM 11 requires no external pins, but is instead directly connected to the logic circuitry 13 through traces formed on the substrate 17. Thus, the width N may be very wide which, in turn, dramatically increases the bandwidth of the DRAM 15.
Additional advantages of the Embedded DRAM 11 over conventional discreet interconnected devices include lower power consumption and lower electromagnetic radiation due to the shorter lengths of conductive traces comprising the internal data bus 21. Furthermore, transmission line effects such as propagation delays are likewise alleviated due to such reduced lengths of the internal data bus 21. The shorter line lengths and corresponding reduced capacitance of individual lines in the bus 21 also reduce the noise resulting when switching the N lines in parallel.
In one application of the Embedded DRAM 11, the logic circuitry 13 is a microprocessor and the DRAM 15 is directly coupled to the microprocessor via the internal data bus 21. As understood by one skilled in the art, a memory controller is typically required between a conventional DRAM and a microprocessor because the DRAM has a much lower bandwidth than the processor. Thus, a conventional DRAM creates a xe2x80x9cbandwidth bottleneckxe2x80x9d that limits the speed at which a computer system including the DRAM and the processor can execute a program. In contrast, in the Embedded DRAM 11 the internal data bus 21 provides a very high bandwidth between the processor 13 and DRAM 15, making the Embedded DRAM 11 well suited to applications requiring very high bandwidths, such as networking, multimedia, and high-resolution graphics systems.
During the manufacture of the Embedded DRAM 11, the DRAM 15 needs to be tested just as with conventional DRAMs. Testing the DRAM 15, however, presents new problems not encountered when testing conventional DRAMs. More specifically, an external memory tester (not shown in FIG. 1) must transfer test data to and from the memory cells in the DRAM 15. The memory tester must be coupled to the DRAM 15 through the external terminals 25 on the Embedded DRAM 11, and must apply address, control, and data signals on such external terminals to transfer data to and from the memory cells in the DRAM 15. Due to the wide internal data bus 21 of the DRAM 15, however, there are many fewer external terminals 25 available on the Embedded DRAM 11 than there are data lines in the internal data bus 21. For example, if the internal data bus 21 is 512 bits wide, the Embedded DRAM 11 cannot include 512 external data terminals plus address and control terminals due to the physical limitations of forming such external terminals 25. Thus, in an Embedded DRAM there is a problem in transferring data between the DRAM and the memory tester in order to test the DRAM.
There is a need for a test circuit in an Embedded DRAM that enables a memory tester to test the DRAM portion of the Embedded DRAM.
The present invention relates to a method and apparatus for testing a memory portion of an Embedded DRAM. According to one inventive aspect of the present invention, a test circuit comprises a test mode terminal adapted to receive a test mode signal and a plurality of first-stage comparison circuits. Each first-stage comparison circuit includes a first input adapted to receive a read data signal and a second input adapted to receive an expect data signal. Each first-stage comparison circuit compares the binary values of the read and expect data signals and develops an inactive first-stage error signal on an output when the compared signals have the same binary values. When the compared signals have different binary values, each first-stage comparison circuit develops an active first-stage error signal on the output. A storage circuit is coupled to the outputs of the first-stage comparison circuits, and latches the first-stage error signals output by the first-stage comparison circuits. The storage circuit sequentially transfers the latched first-stage error signals onto a data terminal of the Embedded DRAM. A test control circuit is coupled to the first-stage comparison circuits, the test mode terminal, and the storage circuit. The test control circuit operates responsive to the test mode signal being active to apply data from addressed memory cells respectively on the first inputs of the first-stage comparison circuits. The test control circuit also applies respective expect data on the second inputs of the first-stage comparison circuits. The test control circuit controls the storage circuit to latch the resulting first-stage error signals and thereafter sequentially transfer the latched first-stage error signals onto the data terminal.
According to another inventive aspect of the present invention, the test circuit includes a second-stage comparison circuit coupled to the storage circuit and to an external terminal of the Embedded DRAM. The second-stage comparison circuit develops an active second-stage error signal on the external terminal when at least one of the first-stage error signals stored in the storage circuit is active. A test control circuit controls the first-stage and second-stage comparison circuits and the storage circuit in response to the test mode signal. When the test mode signal is active, the test control circuit applies data from addressed memory cells respectively on the first inputs of the first-stage comparison circuits and applies respective expect data on the second inputs of the first-stage comparison circuits. The test control circuit controls the storage circuit to latch the resulting first-stage error signals and the second-stage comparison circuit to develop the second-stage error signal on the external terminal.
Another inventive aspect of the present invention includes the test circuit further having a second storage circuit coupled to an external terminal of the Embedded DRAM and to the second-stage comparison circuit. The second storage circuit latches second-stage error signals output by the second-stage comparison circuit and sequentially transfers the latched second-stage error signals onto the external terminal of the Embedded DRAM. A test control circuit controls the first-stage and second-stage comparison circuits, and the first and second storage circuits responsive to the test mode signal. When the test mode signal is active, the control circuit applies data from a group of memory cells respectively on the first inputs of the first-stage comparison circuits and applies expect data on the respective second inputs of the first-stage comparison circuits. The test control circuit controls the first-stage storage circuit to latch the resulting first-stage error signals, and the second-stage comparison circuit to develop the second-stage error signal. The control circuit then controls the second storage circuit to latch the second-stage error signal output by the second-stage comparison circuit. The test control circuit accesses a plurality of groups of memory cells such that the second storage circuit stores a plurality of second-stage error signals. The control circuit thereafter controls the second storage circuit to sequentially transfer the stored second-stage error signals onto the external terminal.

Method and apparatus for testing an embedded DRAM


Copper chromite particles can advantageously be used as black particles in electrophoretic media and displays. Preferably, the copper chromite particles are coated with a silica coating and a polymer coating.

This invention relates to electrophoretic particles (i.e., particles for use in an electrophoretic medium) and processes for the production of such electrophoretic particles. This invention also relates to electrophoretic media and displays incorporating such particles. More specifically, this invention relates to novel black or dark colored electrophoretic particles.
Particle-based electrophoretic displays, in which a plurality of charged particles move through a suspending fluid under the influence of an electric field, have been the subject of intense research and development for a number of years. Such displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption when compared with liquid crystal displays.
The terms "bistable" and "bistability" are used herein in their conventional meaning in the art to refer to displays comprising display elements having first and second display states differing in at least one optical property, and such that after any given element has been driven, by means of an addressing pulse of finite duration, to assume either its first or second display state, after the addressing pulse has terminated, that state will persist for at least several times, for example at least four times, the minimum duration of the addressing pulse required to change the state of the display element. The optical property is typically color perceptible to the human eye, but may be another optical property, such as optical transmission, reflectance, luminescence or, in the case of displays intended for machine reading, pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range. It is shown in the U.S. Published Application No. 2002/0180687 that some particle-based electrophoretic displays capable of gray scale are stable not only in their extreme black and white states but also in their intermediate gray states, and the same is true of some other types of electro-optic displays. This type of display is properly called "multi-stable" rather than bistable, although for convenience the term "bistable" may be used herein to cover both bistable and multi-stable displays.
Nevertheless, problems with the long-term image quality of electrophoretic displays have prevented their widespread usage. For example, particles that make up electrophoretic displays tend to settle, resulting in inadequate service-life for these displays.
Numerous patents and applications assigned to or in the names of the Massachusetts Institute of Technology (MIT) and E Ink Corporation have recently been published describing encapsulated electrophoretic media. Such encapsulated media comprise numerous small capsules, each of which itself comprises an internal phase containing electrophoretically-mobile particles suspended in a liquid suspension medium, and a capsule wall surrounding the internal phase. Typically, the capsules are themselves held within a polymeric binder to form a coherent layer positioned between two electrodes. Encapsulated media of this type are described, for example, in U.S. Pat. Nos. 5,930,026; 5,961,804; 6,017,584; 6,067,185; 6,118,426; 6,120,588; 6,120,839; 6,124,851; 6,130,773; 6,130,774; 6,172,798; 6,177,921; 6,232,950; 6,249,271; 6,252,564; 6,262,706; 6,262,833; 6,300,932; 6,312,304; 6,312,971; 6,323,989; 6,327,072; 6,376,828; 6,377,387; 6,392,785; 6,392,786; 6,413,790; 6,422,687; 6,445,374; 6,445,489; 6,459,418; 6,473,072; 6,480,182; 6,498,114; 6,504,524; 6,506,438; 6,512,354; 6,515,649; 6,518,949; 6,521,489; 6,531,997; 6,535,197; 6,538,801; 6,545,291; 6,580,545; 6,639,578; 6,652,075; 6,657,772; 6,664,944 and 6,680,725; and U.S. patent Applications Publication Nos. 2002/0019081; 2002/0021270; 2002/0053900; 2002/0060321; 2002/0063661; 2002/0063677; 2002/0090980; 2002/0106847; 2002/0113770; 2002/0130832; 2002/0131147; 2002/0145792; 2002/0171910; 2002/0180687; 2002/0180688; 2002/0185378; 2003/0011560; 2003/0011868; 2003/0020844; 2003/0025855; 2003/0034949; 2003/0038755; 2003/0053189; 2003/0076573; 2003/0096113; 2003/0102858; 2003/0132908; 2003/0137521; 2003/0137717; 2003/0151702; 2003/0189749; 2003/0214695; 2003/0214697 and 2003/0222315; and International Applications Publication Nos. WO 99/67678; WO 00/05704; WO 00/38000; WO 00/38001; WO 00/36560; WO 00/67110; WO 00/67327; WO 01/07961; WO 01 /08241; and WO 03/104884.
Known electrophoretic media, both encapsulated and unencapsulated, can be divided into two main types, referred to hereinafter for convenience as "single particle" and "dual particle" respectively. A single particle medium has only a single type of electrophoretic particle suspended in a suspending medium, at least one optical characteristic of which differs from that of the particles. (In referring to a single type of particle, we do not imply that all particles of the type are absolutely identical. For example, provided that all particles of the type possess substantially the same optical characteristic and a charge of the same polarity, considerable variation in parameters such as particle size and electrophoretic mobility can be tolerated without affecting the utility of the medium.) When such a medium is placed between a pair of electrodes, at least one of which is transparent, depending upon the relative potentials of the two electrodes, the medium can display the optical characteristic of the particles (when the particles are adjacent the electrode closer to the observer, hereinafter called the "front" electrode) or the optical characteristic of the suspending medium (when the particles are adjacent the electrode remote from the observer, hereinafter called the "rear" electrode (so that the particles are hidden by the suspending medium).
A dual particle medium has two different types of particles differing in at least one optical characteristic and a suspending fluid which may be uncolored or colored, but which is typically uncolored. The two types of particles differ in electrophoretic mobility; this difference in mobility may be in polarity (this type may hereinafter be referred to as an "opposite charge dual particle" medium) and/or magnitude. When such a dual particle medium is placed between the aforementioned pair of electrodes, depending upon the relative potentials of the two electrodes, the medium can display the optical characteristic of either set of particles, although the exact manner in which this is achieved differs depending upon whether the difference in mobility is in polarity or only in magnitude. For ease of illustration, consider an electrophoretic medium in which one type of particles is black and the other type white. If the two types of particles differ in polarity (if, for example, the black particles are positively charged and the white particles negatively charged), the particles will be attracted to the two different electrodes, so that if, for example, the front electrode is negative relative to the rear electrode, the black particles will be attracted to the front electrode and the white particles to the rear electrode, so that the medium will appear black to the observer. Conversely, if the front electrode is positive relative to the rear electrode, the white particles will be attracted to the front electrode and the black particles to the rear electrode, so that the medium will appear white to the observer.
If the two types of particles have charges of the same polarity, but differ in electrophoretic mobility (this type of medium may hereinafter to referred to as a "same polarity dual particle" medium), both types of particles will be attracted to the same electrode, but one type will reach the electrode before the other, so that the type facing the observer differs depending upon the electrode to which the particles are attracted. For example suppose the previous illustration is modified so that both the black and white particles are positively charged, but the black particles have the higher electrophoretic mobility. If now the front electrode is negative relative to the rear electrode, both the black and white particles will be attracted to the front electrode, but the black particles, because of their higher mobility will reach it first, so that a layer of black particles will coat the front electrode and the medium will appear black to the observer. Conversely, if the front electrode is positive relative to the rear electrode, both the black and white particles will be attracted to the rear electrode, but the black particles, because of their higher mobility will reach it first, so that a layer of black particles will coat the rear electrode, leaving a layer of white particles remote from the rear electrode and facing the observer, so that the medium will appear white to the observer: note that this type of dual particle medium requires that the suspending fluid be sufficiently transparent to allow the layer of white particles remote from the rear electrode to be readily visible to the observer. Typically, the suspending fluid in such a display is not colored at all, but some color may be incorporated for the purpose of correcting any undesirable tint in the white particles seen therethrough.
Both single and dual particle electrophoretic displays may be capable of intermediate gray states having optical characteristics intermediate the two extreme optical states already described.
Some of the aforementioned patents and published applications disclose encapsulated electrophoretic media having three or more different types of particles within each capsule. For purposes of the present application, such multi-particle media are regarded as sub-species of dual particle media.
Also, many of the aforementioned patents and applications recognize that the walls surrounding the discrete microcapsules in an encapsulated electrophoretic medium could be replaced by a continuous phase, thus producing a so-called polymer-dispersed electrophoretic display, in which the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be regarded as capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet; see for example, the aforementioned 2002/0131147. Accordingly, for purposes of the present application, such polymer-dispersed electrophoretic media are regarded as sub-species of encapsulated electrophoretic media.
A related type of electrophoretic display is a so-called "microcell electrophoretic display". In a microcell electrophoretic display, the charged particles and the suspending fluid are not encapsulated within microcapsules but instead are retained within a plurality of cavities formed within a carrier medium, typically a polymeric film. See, for example, International Application Publication No. WO 02/01281, and published US Application No. 2002/0075556, both assigned to Sipix Imaging, Inc.
Although electrophoretic media are often opaque (since, for example, in many electrophoretic media, the particles substantially block transmission of visible light through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in a so-called "shutter mode" in which one display state is substantially opaque and one is light-transmissive. See, for example, the aforementioned U.S. Pat. Nos. 6,130,774 and 6,172,798, and U.S. Pat. Nos. 5,872,552; 6,144,361; 6,271,823; 6,225,971; and 6,184,856. Dielectrophoretic displays, which are similar to electrophoretic displays but rely upon variations in electric field strength, can operate in a similar mode; see U.S. Pat. No. 4,418,346.
An encapsulated or microcell electrophoretic display typically does not suffer from the clustering and settling failure mode of traditional electrophoretic devices and provides further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates. (Use of the word "printing" is intended to include all forms of printing and coating, including, but without limitation: pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; ink jet printing processes; and other similar techniques.) Thus, the resulting display can be flexible. Further, because the display medium can be printed (using a variety of methods), the display itself can be made inexpensively.
However, the electro-optical properties of encapsulated electrophoretic displays could still be improved. Among the remaining problems of encapsulated electrophoretic displays are so-called "rapid white state degradation", a relatively rapid decline in the reflectivity of the white optical state of the display during the first few days of operation. Another problem, which is discussed in detail in the aforementioned 2003/0137521 and WO 03/107315, is so-called "dwell state dependency", which causes the change in optical state of an electrophoretic medium produced by a specific waveform to vary depending upon the time for which the electrophoretic medium has been in a particular optical state before the waveform is applied. Finally, it is advisable to make the white optical state of the display whiter and the black optical state darker.
As discussed in the aforementioned E Ink and MIT patents and applications, the presently preferred form of electrophoretic medium comprises white titania and carbon black particles in a hydrocarbon suspending fluid, this hydrocarbon being used alone or in admixture with a chlorinated hydrocarbon or other low dielectric constant fluid. Most other prior art electrophoretic displays which require a black pigment have also used carbon black for this purpose, apparently largely because the material is readily available in mass quantities and very inexpensive. However, the present inventors and their co-workers have discovered that the aforementioned problems with prior art electrophoretic displays are associated with the use of carbon black for the black electrophoretic particles. Carbon black has a complex and poorly understood surface chemistry, which may vary widely with the specific raw material (typically petroleum) and the exact process used for the carbon black production. Carbon black pigment particles also have a poorly understood aggregate, fractal structure. Furthermore, carbon black is notoriously effective in adsorbing gases and liquids with which it comes into contact, and such adsorbed gases and liquids can change the physicochemical properties of the carbon black surface. Hence, it is difficult to ensure consistent surface properties of carbon black from batch to batch. This is especially problematic in electrophoretic displays, since the electrophoretic particles used are typically so small (of the order of 1 μm) that their properties are dominated by the properties of their surfaces.
It has also been discovered (although this information is not disclosed in the prior art) that carbon black presents certain peculiar difficulties in obtaining proper charging of particles in opposite charge dual particle electrophoretic displays. Specifically, it has been found that when using carbon black and titania as the black and white particles respectively in an opposite charge dual particle electrophoretic display, combinations of charging agents and other materials which produce all positively charged carbon black particles tend to produce a minor proportion of titania particles which are also positively charged. The resultant mixture of negatively and positively charged titania particles leads to contamination of the extreme optical states of the medium, thus adversely affecting its contrast ratio.
Carbon black also has a low density. While this does not affect the operation of the display itself, it does complicate the manufacture of encapsulated dual particle displays. For reasons explained in several of the aforementioned E Ink and MIT patents, it is desirable that an encapsulated electrophoretic medium comprises a single, substantially close-packed layer of capsules. Also, when such an electrophoretic medium is produced by coating capsules on to a substrate, it is desirable that the exposed surface of the capsule layer be reasonably flat, since otherwise difficulties may be encountered in laminating the capsule layer to other layers in the final display. Production of such a substantially close-packed layer with a reasonably flat exposed surface is best achieved by coating capsules which are of substantially the same size. However, the encapsulation processes described in aforementioned E Ink and MIT patents produce capsules having a broad range of sizes, and hence it is necessary to separate out the capsules having the desired range of sizes. Many useful processes for sorting capsules by size rely upon using the density difference between the capsules and a surrounding medium to effect the desired sorting. The low density of carbon black, coupled with the small concentration at which it is used in most electrophoretic media, lead to capsule densities close to that of water, hindering the sorting process.
There is thus a need for a black particle for use in electrophoretic media that does not suffer from the problems associated with the use of carbon black. However, the search for such a black particle is subject to considerable difficulties. Although the optical properties of numerous pigments are of course known from their use in the paint and similar industries, a pigment for use in an electrophoretic display must possess several properties in addition to appropriate optical properties. The pigment must be compatible with the numerous other components of the electrophoretic medium, including the suspending fluid, any other pigment particles present, charge control agents and surfactants typically present in the suspending fluid, and the capsule wall material (if a capsule wall is present). The pigment particles must also be able to sustain a charge when suspended in the suspending fluid, and the zeta potentials of the particles caused by such charges should all be of the same polarity and should not extend over an excessively wide range, or the electrophoretic medium may not have desirable electro-optic properties; for example, if some particles have very low zeta potentials, a very long driving pulse may be required to move such particles to a desired position within the electrophoretic medium, resulting in slow switching of the medium. It will be appreciated that such information relating to the ability of pigment particles to acquire and hold charges is not available for most pigments potentially usable in an electrophoretic display, since such electrical properties are irrelevant to the normal commercial uses of the pigments.
The aforementioned copending application Ser. No. 09/140,846 mentions numerous pigments that are potentially useful in an electrophoretic display. It has now been found that one of these pigment, namely copper chromite (Cu2Cr2O3) has particular advantages for use in electrophoretic media and displays, and this invention relates to electrophoretic media and displays containing copper chromite. It has also been found that certain surface treatments, in particular the formation of layers of silica and formation of polymers attached to the copper chromite particle, substantially as described in the aforementioned copending applications Ser. Nos. 10/063,803 and 60/481,572, improve the performance of the copper chromite particle in electrophoretic media and displays, and this invention also relates to such modified copper chromite particles and electrophoretic media and displays containing them.

Electrophoretic particles, and processes for the production thereof


The present invention is a synthetic microfluidic microvasculature network and associated methods. The synthetic microfluidic microvasculature network mimics the structure, fluid flow characteristics, and physiological behavior of physiological microvasculature networks. Computational methods for simulating flow and particle adherence in synthetic and physiological microvascular systems and methods for determining parameters influencing particle adhesion and drug delivery are also described. The invention has many uses including the optimization of drug delivery and microvascular treatments and in describing disease mechanisms that affect the microvasculature such as inflammation, diabetes and hypertension.

1, Field of the Invention
The present invention is in the field of microfluidics and physiology. More specifically, the invention relates to microfluidic systems that mimic the structure, fluid flow characteristics, and physiological behavior of small physiological vessels such as those found in the microvasculature. The invention has many uses including the optimization of drug delivery and microvascular treatments and in describing disease mechanisms that affect the microvasculature such as inflammation, diabetes and hypertension. The invention is not limited to vessels of the circulatory system but is applicable to all physiological vessels such as lymphatic vessels and glandular ductules.
2, Description of Related Art
Physiological microvascular networks are series of interconnected arterioles, capillaries, and/or venules. The diameters of these vessels range from about 2-10 μm for capillaries and about 10-100 μm for arterioles and venules. In the context of the present invention, the term "microvascular networks" can also be used to describe networks of physiological vessels having diameters of less than about 100 μm such as renal or seminiferous tubules.
A considerable body of work has been developed regarding in-vitro systems for the study of vascular endothelial responses, leukocyte adhesion, and drug carrier delivery in the presence of flow (Blackwell 2001; Burch 2002; Chang 2000; Cozens-Roberts 1990; Crutchfield 2000; Dickerson 2001; Goetz 1994; Kiani 2002; Patel 1999; Patil 2001; Sayed 2001). For example, in-vitro flow chambers have facilitated the identification of biological molecules involved in the adhesion of leukocytes to the endothelium. It is now known that the dynamics of cell adhesion to vascular endothelial cells are controlled by a combination of biochemical and macro-properties such as vessel size and flow rate. These results have led in part to an effort to understand endothelial cell-leukocyte interactions using carefully controlled in-vitro flow cell experiments.
The adhesion of particles such as leukocytes, platelets, liposomes/lipisomes, and microencapsulated drug carriers to microvascular endothelium is also greatly influenced by the geometric features of the vasculature, local hemodynamics, and numerous receptor-ligand interactions between endothelial cells and particles. Local hemodynamic factors associated with microvascular geometry such as wall shear stress, pressure, and residence time influence the rates, amounts, and distributions of particle adhesion as well as endothelial cell morphology and function. This complex interplay between flow, cells, and particles is still poorly understood and it is not possible to predict, for example, adhesion patterns and numbers of adhered particles in the microvasculature based on current in-vitro flow cell technologies. The present invention advances in-vitro flow cell technology so that adhesion patterns and numbers of adhered particles in the microvasculature, for example, can be predicted.
In-vitro flow chambers typically comprise a single flow channel formed by two plates or slides separated by a gap. The cross section of the flow channel is typically a flat rectangle with constant dimensions. The flow chambers are usually transparent and are perfused at low Reynolds numbers to match wall shear stresses observed in blood vessels in-vivo. The lower plates of these flow chambers are coated with either protein or adherent endothelial cells to simulate the surface properties of physiological vessels (Luscinskas 1994). The chambers are typically mounted on a microscope stage and events are recorded with a high-speed camera and stored for subsequent analysis.
Recently, efforts to construct microfluidic flow chambers have been reported. These efforts typically feature linear channels with conventional rectangular cross sections and constant cross sectional areas. For example, Lu et al. (2004) reports the fabrication of a device on PDMS for varying shear profiles. Unlike the present invention, this and other existing device do not account for the geometric variations and the interconnectedness found in microvascular networks and lack the ability to effectively reproduce or simulate the flow patterns and particle adhesion patterns observed in physiological vessels and microvasculature.
The smallest cross section of commercially available in-vitro flow chambers is typically about 2500 μm×125 μm, which is significantly larger than arterioles, capillaries, and venules. They do not provide realistic sizes and geometries corresponding to complex combinations of thoroughfare channels, bifurcations, junctions, convolutions, and/or variable diameters found in in-vivo microcirculation. These complex features determine local fluid dynamic profiles and thereby local values of shear stress, pressure, residence time, and velocity. Complex geometrical features also strongly influence the transport and adhesion of cells and other particles to sites in the microvasculature. In diseased networks such as those affected by tumor growth, stenoses, arteriosclerosis, diabetes, and radiation therapy, both flow profiles and microvasculature features are different from healthy networks. Examples include medullary arteriolar tortuosity seen in hypertension and intraparenchymal arteriolar-to-arteriolar anastomoses in pathological conditions in the cerebrum. Existing in-vitro flow chambers, however, having idealized rectangular or circular duct geometries cannot be modified to reflect changes that occur with disease.
Some attempts have been made to improve on the scale of in-vitro microvascular channels. Cokelet et al. (1993) fabricated an in-vitro microvascular channel to study blood flow by photolithography on microscope slide glass. Frame et al. (1995) generated idealized (straight) semi-circular microvascular channels (20-50 μm) on glass to mimic the arteriolar microcirculation. They were also successful in growing endothelial cells on these channels. However, both studied idealized (straight) microchannels that did not account for either the interconnectedness or variations found in in-vivo microvascular networks.
The complexity of the flow in microvascular networks necessitates the use of sophisticated models to analyze and understand flow behavior. Mathematical modeling has been used extensively to study particle/cell adhesion in a flow environment. Starting with the pioneering work of Hammer & Lauffenburger (1987), Cozens-Roberts et al. (1990) derived an analytical expression for the shear stress and adhesive force relationships in flow chambers. Hammer and coworkers (1992) developed mathematical models for cell attachment and rolling. The dependence of rolling adhesion of cells on vessel diameters and other parameters has been addressed in several notable works including, Goldsmith & Turitto (1986), Schmid-Schoenbein et al. (1975), House & Lipowsky (1988) and Chapman & Cokelet (1998). The biochemical processes of receptor-ligand attachment have been extensively studied as well (Goetz 1994; Hammer 1992). Chapman & Cokelet (1993, 1998) used computational fluid dynamics modeling (CFD) to analyze the hemodynamic impact of leukocytes adherent to the wall of post-capillary venules. Chang et al. (2000) disclosed an "Adhesive Dynamics" technique for studying and developing a state diagram for cell adhesion in flow, under simple conditions.
All of the numerical studies mentioned above are based upon simple, idealized flow chambers with regular geometries and have not examined flow profiles and shear stresses in realistic in-vivo microvasculature scenarios with relevance to cell adhesion. In contrast, the present invention includes a CFD-based model framework that analyzes fluid flow and particle motion/adhesion in the context of realistic in-vivo networks that correspond to the fabricated vascular networks of the invention. The CFD models can be used to analyze and interpret results from experiments and to convert them into information used to assist with the design of experiments and treatment protocols.
In summary, there remains a need in the art for an in-vitro flow chamber that accurately simulates the anatomical and hemodynamic properties of physiological microvascular networks. There is also a need for methods of using such a flow chamber that describe and predict the behavior of particles and cells in microvascular networks. Such a flow chamber and methods can be used, for example, to screen materials and methods for optimal drug delivery to both healthy and diseased microvasculature.

Synthetic microfluidic microvasculature network


A microkeratome and related surgical methods for performing lamellar keratotomies are provided. The microkeratome includes a guide ring assembly for placement on the eyeball, or ocular globe such that the globe's cornea protrudes therethrough. The guide ring can be temporarily fixed to the ocular globe, immobilizing the eyeball relative to the instrument. A cutting blade suitable for corneal resections is carried in a cutting head over the guide ring through a cutting path defined by the guide ring. An adjustable float head, also generally known as a plaque, is connected to the cutting head for at least partially compressing the cornea ahead of the blade, so as to set the desired thickness of the corneal resection. The cutting head and float head can be driven across the guide ring, whereby the blade cuts at least partially through the cornea to perform the lamellar keratotomy. Various surgical corrections are obtainable through the use of arcuate and oblique plaques, as an alternative to planar plaques or float heads, where appropriate.

1. Field of the Invention
The present invention relates to medical instruments and methods for performing eye surgery to correct irregularities of the cornea. More particularly, the present invention relates to mechanical instruments known as microkeratomes, and related surgical methods for performing lamellar keratotomies.
2. The Related Art
The first microkeratome for performing corneal resections was developed in 1962 by one of the present inventors, Doctor Jose I. Barraquer, and is shown generally in FIG. 1A. This microkeratome includes a guide ring which is fixed to an ocular globe, or eyeball, with the aid of a partial vacuum applied through the ring. The guide ring immobilizes the ocular globe, maintains the tension of the globe, and regulates the diameter of the corneal resection. A portion of the microkeratome called a cutting head is supported within a channel in the guide ring for guided linear movement of the microkeratome across the ring by the surgeon. The cutting head carries a cutting blade that is oscillated by a motor-driven eccentric transverse the channel as the instrument is moved through the cutting path defined by the channel. The cutting head carries a removable, lower planar member that compresses the ocular globe ahead of the oscillating blade, to permit the blade to cut a lamella having a lower surface that is parallel to the surface of the cornea that is compressed by the planar member. The planar member is interchangeable with similar planar members of differing thicknesses, so as to vary the thickness of the resectioned corneal "disk. "
Numerous variations on the Barraquer microkeratome have been made since 1962, including the apparatus that is the subject of U.S. Pat. No. 4,662,370 assigned to Carl-Zeiss-Stiftung of Germany. The '370 patent describes a microkeratome having interchangeable inserts with convex, concave, and planar surfaces that engage and compress the cornea for producing a corneal resection of predetermined form and curvature. The inserts are set within a stationary planar member that is fixed to the guide ring. The cutting blade is moved through a cutting path parallel to the planar member defined by a gap between the planar member and the guide ring, and oscillates transverse the path.
While apparently effective to permit resections of corneal lenticula, the apparatus of the '370 patent lacks means for controlling, or automating the rate of movement by the cutting head across the guide ring, and is therefore prone to binding up in the corneal tissue, or otherwise producing imprecise resections under unsteady progress by the surgeon's hand. Furthermore, there is no apparent means for changing the depth or thickness of the corneal resection. Also, this apparatus is limited to use in lamellar keratectomies (excision of a corneal section), as opposed to lamellar keratotomies (incision through the cornea).
The problem of controlled movement across the guide ring has been addressed by the instrument described in U.S. Pat. No. 5,133,726, which has been reissued as Re 35,421, to Luis A. Ruiz and Sergio Lenchig G. The '726 and '421 patents disclose a microkeratome, shown in FIG. P2, having a gear transmission assembly for moving the instrument through the cutting path at a controlled rate of speed. The gears are driven by the same motor that drives the cutting blade and engage a track atop the guide ring. Thus, the automated transmission system is an improvement over the instrument of the '370 patent, but in practice it has been found that the weight of the motor in the instrument produces a large moment through the handle of the device. This moment, coupled with the forward positioning of the gear that engages the guide ring track, causes the rear surface of the cutting head to bind in its engagement with the guide ring. At best, this results in uneven travel by the instrument during the surgery and unnecessary pressure fluctuations within the eye. At worst, such binding can cause irregular cutting of the cornea that produces leucoma, or the induction of an astigmatism.
The relatively recent technological development of intrastromal refractive surgery led to the creation of instruments and methods for performing incomplete lamellar temporo-nasal keratotomies, which leave a peripheral residue of corneal tissue uncut to act as a "nasal hinge." The nasal hinge permits the corneal disk to be lifted for exposure and carving of the stromal layer, such as by a laser. The use of a laser to perform stromal carving in association with an incomplete lamellar keratotomy is referred to as "Laser Intrastromal Keratomileusis" ("LASIK").
In similar fashion to the original Barraquer device, the microkeratome of the '726 and '421 patents include a forward planar member in the lower portion of the cutting head that is interchangeable with similar planar members of varying thicknesses. For the planar member to be interchangeable, however, a slotted portion of the cutting head extends substantially forward of the cutting blade to receive the planar member. This, and the fact that the transmission gears are positioned outside the cutting head, result in a fairly large surface area, or "footprint" for the instrument. The large footprint restricts the manner in which the microkeratome can be used, and generally requires that it be moved across the cornea from the temporal region adjacent the eye, producing the vertical nasal hinge when performing incomplete lamellar keratotomies. The vertical nasal hinge has at least two deficiencies. First, the corneal disk resulting from the LASIK, or other procedure, will be vertically displaced after surgery, and/or pleated to some extent by the opening and closing of the upper eyelid. Second, the formation of a vertical nasal hinge on the corneal disk increases the likelihood of accidental ablation of the hinge during the correction of an astigmatism, which is typically performed with vertical cutting motions across a major diameter of the cornea.
The large surface area of the planar member, or plaque, described in the '726 patent is designed to substantially compress the entire cornea at any one time. Such action produces unnecessarily high intraocular pressure, which unduly stresses the eye and could result in complications during surgery. Furthermore, the interchangeable planar members lack means for indicating the thickness of the resection to be provided by the respective members. This creates the possibility that a planar member having the wrong thickness will be inserted into the cutting head. In such an event, the instrument might perform an exaggerated cut and perforate the ocular globe, causing serious consequences.
In response to the shortcomings described herein, it is an object of the present invention to provide an improved microkeratome wherein the cutting head is moved across the cornea by sweeping pivotal motion relative to a fixed point on a guide ring positioned on a patient's eye.
It is a further object that such pivotal motion be induced automatically by the engagement of gears with an output shaft that induces rotation about a pivot post connected to a guide ring at the fixed point.
It is a further object to provide an improved microkeratome having an adjustable float head, or plaque, connected to the cutting head for varying the thickness of corneal resections without having to disassemble or replace a component of the instrument.
It is a further object that the adjustable float head be provided with indicia for indicating the selected depth of cut, whereby inadvertent mistakes regarding the thickness of the resection are less likely to occur.
It is a further object of the present invention that the float head exhibit a small surface area to permit corneal resections without the cutting head or float head exceeding the rim of the guide ring. In this manner, oblique and lower-upper resections of the cornea can be performed during a lamellar keratotomy, whereby the risk of inadvertent ablation of the corneal hinge during an astigmatic correction, as well as the extent of fold and displacement of the corneal disc generated by the sweeping of the upper eyelid, are reduced.
It is a further object that the float head impart only the minimum pressure upon the ocular globe that is necessary to compress the cornea for a uniform resection.
It is a further object that the transmission gears be positioned inside the side walls of the cutting head to minimize the surface area of the instrument, whereby a superior corneal hinge lying in the upper region of the cornea can be produced.
It is a further object that, in a linearly driven embodiment of the present invention, the drive gear which engages the guide ring be positioned rearwardly with respect to the cutting head to eliminate any binding between the rear lower surface of the cutting head and the guide ring.
It is a still further object of the present invention to provide a means for selectively limiting the cutting range of the microkeratome through the cutting path defined by the guide ring, so as to regulate the formation of the corneal hinge during a lamellar keratotomy.
It is a still further object to provide means for automatically returning the microkeratome to its initial position on the guide rings, upon reaching the selected limit of the cutting range.

Microkeratome and method of performing corneal resections


An electroless plating device which comprises an electroless plating tank for accommodating an electroless plating solution; a draft pipe provided in the electroless plating tank for blowing air into the electroless plating solution; and a shield plate having perforations provided between an object of plating and bubbles blown out from the draft pipe, a size of each of said perforations being of dimensions whereby the bubbles cannot pass through the perforations.

1. Field of the Invention
The present invention relates to an electroless plating device which is utilized in performing electroless plating, and particularly to an electroless plating device capable of uniformly depositing material for plating.
2. Discussion of Background
Conventionally, in performing the electroless plating, air is blown into a plating solution for the purpose of preventing self-decomposition of the plating solution.
As such an electroless plating device, a device is known which is described in, for instance, Japanese Unexamined Publication No. 312983/1988. A front view of the device described in the publication is shown in FIG. 4.
In FIG. 4, a reference numeral 1 designates an electroless plating tank for accommodating an electroless plating solution 6, 2, a draft pipe for blowing bubbles into the electroless plating solution 6, 3, bubbles (air), and 4, an object for plating. In the electroless plating device having such a construction, the electrolytic plating solution 6 is provided in the electroless plating tank 1, of which temperature is maintained at a predetermined temperature. Next, air is blown from a draft pipe 2 into the electroless plating solution 6. The object for plating 4 is immersed in the electroless plating solution, thereby performing the plating.
However, in the conventional electroless plating device, since blowing-out openings of the draft pipe 2 are provided at the bottom side of the object for plating 4, the bubbles 3 blown out from the blowing-out opening contact the object for plating 4. Since the electroless plating solution 6 does not contact the object for plating 4 at a portion thereof contacting the bubbles 3, a material for plating is not deposited at the portion contacting the bubbles 3. Furthermore, at the portion contacting the bubbles 3 wherein the material for plating is not deposited, the surface of the object for plating 4 is oxidized. Accordingly, the material for plating is not deposited at the portion hereinafter, the deposition of the material for plating becomes nonuniform.