The present invention provides a method and apparatus for mathematically calculating an optimal transmission input torque value for the inertia phase and the torque phase of a ratio change. Engine output is then altered by an amount necessary to change the actual value of the transmission input torque to the calculated optimal value of transmission input torque. The timing of the clutch elements during the power-on skip through neutral downshift is established by calculating delay periods for the off-going and on-coming clutches such that a predetermined desired shift time is met. The power-on skip through neutral downshift is thereafter adaptively controlled so that aberrations are diagnosed and corrected during subsequent downshifts. The invention is carried out by monitoring engine and/or transmission characteristics including input speed, output speed and shift duration during a downshift and identifying departures from acceptable patterns. Each type of departure calls for a particular remedy, and a suitable adjustment is calculated thereafter implemented by changing one or more initial conditions for the next shift of the same type.

Generally, a motor vehicle automatic transmission includes a number of gear elements coupling its input and output shafts, and a related number of torque establishing devices such as clutches and brakes that are selectively engageable to activate certain gear elements for establishing a desired speed ratio between the input and output shafts. As used herein, the terms "clutches" and "torque transmitting devices" will be used to refer to brakes as well as clutches.
The transmission input shaft is connected to the vehicle engine through a fluid coupling such as a torque converter, and the output shaft is connected directly to the vehicle wheels. Shifting from one forward speed ratio to another is performed in response to engine throttle and vehicle speed, and generally involves releasing or disengaging one or more clutches (off-going) associated with the current speed ratio and engaging one or more clutches (on-coming) associated with the desired speed ratio. Downshifts that skip through neutral include those wherein two off-going clutches associated with the current speed ratio are released and two on-coming clutches associated with the desired speed ratio are engaged during the ratio change such as, for example, a sixth gear to third gear ratio change or a fifth gear to second gear ratio change.
The speed ratio is defined as the transmission input speed or turbine speed divided by the output speed. Thus, a low gear range has a high speed ratio and a higher gear range has a lower speed ratio. To perform a downshift, a shift is made from a low speed ratio to a high speed ratio. In the type of transmission involved in this invention, the downshift is accomplished by disengaging two clutches associated with the lower speed ratio and engaging two clutches associated with the higher speed ratio, to thereby reconfigure the gear set to operate at the higher speed ratio. Shifts performed in the above manner require precise timing in order to achieve high quality shifting.
The quality of shift depends on the cooperative operation of several functions, such as pressure changes within on-coming and off-going clutch apply chambers and the timing of control events. Moreover, manufacturing tolerances in each transmission, changes due to wear, variations in oil quality and temperature, etc., lead to shift quality degradation.

Method and apparatus for adaptive control of power-on skip through neutral downshifts


The present disclosure provides a self-cleaning injector nozzle or other fluid conduit that maintains deposits at a low level by sonic tuning the shock wave generated during fluid flow through that nozzle or conduit. Methods of producing an injector nozzle and a method of cleansing deposits from liquid or gaseous fluids are also disclosed.

Injector coking is a serious problem in direct injected internal combustion engines, because the injectors are in contact with the harsh environment of the combustion chamber. Because of the high temperatures, fuel decomposes in the injector nozzle and lays down a deposit which both restricts flow, and distorts the symmetry of the spray. As this deposit grows with operation, the internal dimensions of the nozzle change.
The buildup of deposits in the combustion chamber can alter engine performance by impairing fuel economy, regulated emissions, and driveability, and in the worst case scenario causing engine damage. A detailed account of such deposits, problems and some attempted solutions can be found in S.A.E. Technical Paper No. 902105 (1990) by G. T. Kalghatgi. Carbonaceous deposits are especially problematic for fuel injectors located within the engine combustion chamber. Direct injection spark ignition (DISI) engines include a fuel injector injecting fuel directly into the combustion chamber.
If the fuel injector could be made to resist the carbonaceous deposits, existing fuels and fuel injector designs could be utilized. In the past, components have been coated with amorphous hydrogenated carbon to increase hardness and durability, decrease friction and wear and protect against corrosion. As described in U.S. Pat. Nos. 5,249,554, 5,309,874, and 5,237,967 assigned to Ford Motor Company, and incorporated herein by reference, power train components have been coated with such carbon film coatings to reduce friction and wear related thereto. More recently, coatings have also been applied in an effort to reduce deposit formation. One example is U.S. Pat. No. 3,552,370, issued to Briggs et al, which describes a coating, and method of application, including the constituents of nickel, aluminum and copper for the purpose of reducing heat transfer from the combustion chamber to foster a more complete combustion.
Fuel additives alone typically are ineffective once fuel injectors have become fouled with substantial amounts of deposits such that the ability of the additive package to cleanse the injector is overcome.
Accordingly, there remains a need for fuel injectors that are capable of reducing and preventing the growth of carbonaceous deposits, especially so as to be able to keep deposits at a sufficiently low level that they may effectively be held at operable levels by fuel additives.

Fuel injector adapted to remove deposits by sonic shock


A heat exchanger fin includes a combination of a flat section, a wavy section, and a slit section arranged successively in a first direction, in order to compensate for different velocities of air passing across those sections, respectively, in a second direction transversely of the first direction, and thereby provide a uniform heat exchange rate across the fin.

1. Field of the Invention
The present invention relates to a fin for a heat exchanger (e.g., an evaporator or a condenser) of an air conditioner.
2. Discussion of Related Art
As shown in FIG. 1, a conventional heat exchanger of an air-conditioner includes a plurality of parallel plates or fins 20 which are arranged between two end plates 10 at predetermined intervals, in order to cool air necessary for an air-cooling operation or in order to heat air for a heating operation when the air circulates. A plurality of heat transmission pipes 30 extend perpendicular to the end plates 10 and the fins 20, and are arranged in zigzag fashion. The pipes conduct refrigerant and transmit heat from the refrigerant to the fins 20. A plurality of return pipes 40 are connected to the ends of adjacent heat transmission pipes 30.
The fin 20 can be flat as shown in FIG. 2A, or wavy (FIG. 2B), or have slit portions in a direction of air current flow as shown in FIG. 2C.
Therefore, a conventional heat exchanger fin has one of the three above-described shapes and is thus of generally uniform shape from an upper end to a lower end thereof. That means that the heat exchanger fin exhibits a uniform heat transfer characteristic across the region between its vertical ends. However, if the velocity distribution of the air current is not uniform from one end to the other, then the rate of heat exchange between the air and fin will not be uniform. For example, if the air velocity S became gradually lower toward the bottom end of the fin, as represented in FIG. 3, for example, then the fin of FIGS. 1 and 2 would not transfer heat at a uniform rate from top to bottom. Another factor that can affect the rate of heat transfer from one end of the fin to the other is the rate of refrigerant flow through the pipes; if the flow is not uniform, then the rate of heat transfer between the pipes and the fins may vary from one end of the fin to the other.
A non-uniform heat exchange rate along the fin can reduce the overall heat exchange efficiency.


Integrated circuits where the standard isolation cell, at power island boundaries, also includes a protection device, which clamps transient voltages.

The present application relates to systems and integrated circuits which include multiple independently powered-up "power islands" inside a single integrated circuit.
Many portable electronic systems are critically limited by battery life. For example, users do not like heavy cell phones, but users also do not like their cell phones to run out of power and shut down. One way to improve battery life is to increase the energy efficiency of the electronics components in the portable system.
As the constraints of low-power integrated circuits have steadily become tighter, the technique of power islands has become more important. In this technology some portions of an integrated circuit are powered up only on an "as-needed" basis.
It should be noted that power islands technology is very different from smart power technology. See e.g. Smart Power ICs (2.ed. Murari et al. 1995). In smart power technology logic or mixed-signal stages, operating at normal supply voltages, are combined in the same chip with higher-voltage driver circuits. Special device structures, which would not be used in a pure logic or mixed-signal chip, are commonly used to permit use of both high-voltage and low-voltage areas.
The use of on-chip power islands has many advantages for reducing power consumption, but the inventors have realized that there are also some surprising difficulties, which are addressed by the various inventions described in the present application.
Some of the points of invention will now be described, followed by additional explanation of the benefits of those points.

Systems, circuits, chips and methods with protection at power island boundaries


A device for storing information electronically and which has a pen-sensitive screen enabling a user to make freehand input has the screen divided into two areas--a main area and a subsidiary area adjacent the main area.. The user can tag items of freehand input causing a tag item to be displayed alongside the freehand input and can subsequently manipulate (eg delete, move, copy) the freehand input by selecting and manipulating the associated tag item.. Tag items provide a permanent way of structuring data and are an elegant way of uniting several data manipulations.

There are already several pen-based handheld computer products on the market for the storage and manipulation of personal data. Examples of these are the Apple Newton, the Tandy Zoomer and the Amstrad PenPad. In these products the user has to become familiar with several unrelated mechanisms in order to perform manipulations on the data stored in the device. The term `manipulations` refers to operations such as moving, deleting, copying etc of data. In addition, the methods of selecting data for manipulation usually effect only a transient selection so that further manipulation of the same data requires the data to be reselected.

Freehand input information management device and method


A process for absorbing silver from photographic hypo solutions involves passing the hypo solution through a bed consisting of a multitude of a sponge product confined within a vessel. The sponge product is derived from an open-celled cellulosic sponge into which there has been incorporated 30% to 80% by weight of a polymer produced by the thermal interaction of polyethyleneimine (PEI) with a polycarboxylic acid. The polymer further contains an activating multivalent cation and between 90% and 300% water. Silver is eluted from the sponge product employing aqueous solutions of a complexing agent such as an ammonium compound or a cyanide compound. Following a water wash, the bed of sponge product is ready for its next cycle of silver absorption.

1. Field of the Invention
This invention concerns the recovery of dissolved silver from solutions having been employed for the processing of silver-containing photosensitive materials.
2. Description of the Prior Art
Photosensitive materials such as films and papers employed for black-and-white photography generally have an emulsion layer which contains a finely divided silver halide such as the chloride or bromide. In the course of the development and fixing of the image within the emulsion layer, molecules of silver halide which are not converted to metallic silver by the developer are dissolved out of the emulsion layer by a "hypo" solution which generally employs a thiosulfate.
Following a certain amount of use, the hypo solution becomes spent, and must be discarded. Although it is desirable to recover the dissolved silver for its economic value, it is more important to recover the silver because it is highly toxic, and should not be indiscriminately dumped into a convenient sewer line. The United States Environmental Protection Agency has indicated that industrial effluents should contain less than 5 parts per million (ppm) silver, and drinking water should contain less than 0.05 ppm silver. Techniques generally employed for removing silver from spent hypo include electrodeposition, and treatment with a sacrificial metal such as steel wool. Hypo solutions emergent from an electrolytic cell which removes silver by electrodeposition upon electrodes will have silver concentrations between about 50 and 200 ppm. Hypo solutions emergent from steel wool systems will have unpredictably high levels of silver, depending upon the state of exhaustion of the steel wool, and will contain undesirably high levels of dissolved iron.
Attempts have been made to utilize ion exchange resins to remove the silver from spent hypo. Because the dissolved silver is in an anionic form such as silver thiosulfate Ag(S.sub.2 O.sub.3).sub.2.sup.-3, an anion exchange resin must be employed. However, ordinary anion exchange resins are not sufficiently selective to discriminate between the silver thiosulfate anion and unreacted thiosulfate and sulfite anions present in the hypo solution.
U.S. patent application Ser. No. 07/808,884, filed Dec. 18, 1991, now U.S. Pat. No. 5,180 concerns a specialized chelation-type ion exchange resin having the ability to selectively remove silver thiosulfate from spent hypo solutions. Although a worthwhile accomplishment, such removal of silver from hypo solutions would be even more practical if the silver could be eluted from the resin, permitting repeated recycling of the resin. Such elution and recycling is not disclosed in said Patent Application.
The usually employed procedure for eluting absorbed species from an anion exchange resin and re-using the resin involves treatment of the resin with strong solutions of anions that can replace the absorbed anion. In the case of the aforesaid chelation-type resins, especially when disposed within an open-celled sponge, treatment with strong solutions of the usual anions has bee-,i found to be poorly effective in eluting absorbed silver.
In the several aforesaid techniques for removing silver from photoprocessing effluents, the efficiency of silver removal is generally inversely dependent upon the rate of flow of the effluent. The efficiency of silver removal is also dependent upon the degree of saturation of whatever device or material is employed.
It is accordingly an object of the present invention to provide a process for removing silver from photoprocessing hypo solution.
It is a further object of this invention to provide a process as in the foregoing object employing a chelation-type ion exchange resin which removes said silver by selective absorption.
It is another object of the present invention to provide a process of the aforesaid nature wherein the silver absorbed on said resin can be eluted, and the resin can be re-used in said process.
It is a still further object of this invention to provide a process of the aforesaid nature wherein the efficiency of silver removal has reduced dependency upon the flow rate of said hypo solution and the degree of saturation of said resin with silver.
It is yet another object of the present invention to provide a process of the aforesaid nature which involves low capital investment and low operating costs.
These and other beneficial objects and advantages will be apparent from the following description.

Process for recovering silver from photographic chemical effluent


A circular knitting machine creel for a plurality of bobbins which are supported in tiers by a circular cylindrical frame, comprising a carrier located inside the frame, at least one blower supported by the frame, having an air outlet connection directed somewhat radially outward, the blower moving on a circular path whose axis coincides essentially with the axis of the frame.

Circular knitting machine creels are bobbin frames in which a number of bobbins are arranged in a circle and in tiers above one another. Threads drawn off from the bobbins are fed to knitting machines. When threads are drawn off, fuzz is produced which collects on parts of the frame and on the floor and makes it necessary to clean the frame and floor area periodically. Unavoidably, fuzz collects on parts of the frame, and an accumulation often comes loose from the frame and is carried along by a thread. This can result in a fuzz accumulation being embedded in the stitches of the knitwear and perhaps lead to substandard knitwear. Embeddings of this type can usually be easily seen since there are bobbins of different colours on the bobbin frame.


An ultra low density polyolefin foam having a density of about 0.6 to about 1.5 pounds per cubic foot comprising a heat-plastified mixture comprising (1) a non-elastomeric olefin polymer resin selected from the group consisting of ethylene homopolymers, non-elastomeric copolymers of ethylene and a copolymerizable monomer, and propylene homopolymers; (2) an elastomer in an amount of about 3 to about 30 wt. parts per 100 wt. parts of said non-elastomeric olefin polymer resin; (3) polystyrene in an amount of about 1 to about 15 wt. parts per 100 wt. parts of said olefin polymer resin; (4) a stability control agent selected from the group consisting of partial esters of long chain fatty acids with polyols, higher alkyl amines, fatty acid amides, and olefinically unsaturated carboxylic acid copolymers, and (5) a hydrocarbon blowing agent having from 1 to 6 carbon atoms and a boiling point between -175.degree. C. and 50.degree. C., said heat-plastified mixture being at a temperature and a pressure which does not allow said mixture to expand, foamable compositions for making said low density polyolefin foam and process of making said foam.

1. Field of the Invention
This invention pertains to the art of making foamed low density polyolefin plastic of relatively large thickness and relatively large lateral cross-section and having a density of about 0.6 to about 1.5 pounds per cubic foot (pcf). More specifically, this invention pertains to the art of making ultra low density foamed plastic boards, planks, beams and the like of substantial dimensions measuring several inches thick and wide and a few to several feet long used primarily for cushioning, packaging, building insulation, flotation, sound deadening and other utilities.
2. Description of the Prior Art
Heretofore, polyolefin foamed plastics in the form of planks, beams, etc. were produced using a variety of blowing agents. For example, it has been common practice to use chlorofluorocarbons (CFC's) and, more recently, hydrochlorofluorocarbons (HCFC's) as blowing agent. Such blowing agents have been found to deplete the planet Earth's ozone layer which serves as a shield to protect the planet from cancer-promoting ultraviolet radiation. Governmental pressure is mounting to severely restrict the release of CFC's and HCFC's to the atmosphere in order to slow down or stop the depletion of the ozone layer.
There is great environmental and commercial interest in the elimination of all ozone-depleting chemicals used as blowing agents. While HCFC's have a lower ozone depletion potential (ODP) than CFC's, the level is still unacceptably high and therefore the use of HCFC's is also coming under greater regulation. It is possible to make polyolefin foam using light hydrocarbons such as isobutane which, however, leads to a worsening of physical properties, e.g., a decrease in thermal stability.
U.S. Pat. No. 3,067,147 (Rubens et al) discloses the production of polyethylene foam having a density as low as 1.7 pcf using 1,2-dichloro-tetrafluoroethane. There is no disclosure of isobutane as a blowing agent or of any stability control agent. This patent discloses that other hydrocarbon blowing agents produce foams having non-uniform large cells.
U.S. Pat. No. 3,379,802 (Raley et al) and U.S. Pat. No. 3,766,099 (Kawai et al) disclose polyethylene foams containing synthetic elastomers but fail to disclose polyolefin foams having densities as low as about 0.6 pcf. The lowest density foam disclosed by Raley et al is 1.7 pcf and the lowest density foam disclosed by Kawai et al is 1.68 pcf. Kawai et al fails to utilize polystyrene or a stability control agent or an isobutane blowing agent and Raley et al fails to disclose the utilization of polystyrene and a stability control agent.
U.S. Pat. Nos. 4,370,378 and 4,387,169 (Zabrocki et al) disclose polyethylene foams alleged to have densities of 1.1 to 1.88 pcf. The Zabrocki et al patents assert that the low densities are achievable by special mixing procedures. There is no disclosure in these patents of using an elastomer, polystyrene, a stability control agent or isobutane. To the contrary, the patents urge the use of ozone-depleting blowing agents such as the CFC's.
U.S. Pat. Nos. 4,640,933, 4663,361 and 4,694,027 (Park) disclose polyolefin foams having densities between 2.19 pcf and 2.66 pcf but fail to disclose polyolefin foams of lower densities or the use of a synthetic elastomer or the achievement of densities as low as about 0.6 pcf.
U.S. Pat. No. 4,652,590 (Hoki et al) discloses the manufacture of low density polyethylene foams using CFC blowing agents. The patent fails to disclose the use of a synthetic elastomer or a stability control agent or isobutane as blowing agent.
U.S. Pat. Nos. 3,893,957, 4,721,591, 4,738,810 and 4,824,720 each disclose the manufacture of polyolefin foams but fail to disclose the use of isobutane or other hydrocarbon blowing agent or the use of stability control agents.
U.S. Pat. No. 4,379,859 (Hirosawa et al) discloses prefoamed particles of polypropylene produced by dispersing the resin particles in water followed by release into the atmosphere and drying.
U.S. Pat. Nos. 4,020,025 and 4,847,150 disclose polyolefin foams containing hydrogenated styrene-butadiene block copolymers but fail to disclose any foams containing the elastomers used in the present invention to produce ultra-low density foams.

Ultra low density polyolefin foam, foamable polyolefin compositions and process for making same


Methods, and system, and entertainment device are provided for identifying a user. A method includes detecting acceleration of a user manipulated component, comparing the detected acceleration with user acceleration that is associated with a user of the electronic device, identifying the user of the electronic device based on the comparison of the detected acceleration and the user acceleration, and operating the electronic device based on the identified user of the electronic device.

Identification of a user of an electronic device has long been either desirable or necessary, depending on the device and the particular environment in which the device is used. For example, access to a computer system or communication network is often strictly controlled or regulated, especially when the data accessible on such a system is of an extremely sensitive or confidential nature, such as corporate, financial, medical, or military records. Typically, the system being protected requires a prospective user to provide some proof of identity, such as a user name and/or password or other confidential data, before the user is granted to access the system.
Various circumstances, such as lost or forgotten passwords, stolen passwords, and other maladies, often lead to either an authorized user being denied access to a system, or an unauthorized user being granted access. Also, memorization and entry of user names and passwords, or other identifying information, is often considered tedious and overly time-consuming.
In response, alternative ways of securely identifying a user have been implemented or proposed. For example, the use of fingerprint scanners, retinal scanners, and similar devices which measure some user physical characteristic have been proposed to identify potential users to restrict access to a computer system to those authorized to do so. The use of such devices typically eliminates the need to enter a password or other identifying data, thus reducing the time required to access the secured system. Some systems, however, may not involve the extremely sensitive or confidential data that warrant such intensive security measures.
Accordingly, it is desirable to provide an improved method of identifying a user. Furthermore, other desirable features and characteristics of the embodiments disclosed herein will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.

Determining remote control state and user via accelerometer


Known thermal spray apparatus are modified to achieve thermal spray coatings of increased hardness. Thermal spray apparatus operate to develop a plasma stream for introduction to a nozzle, for eventual application to the surface of a substrate. Upon entering the nozzle, the plasma stream is passed through a plasma cooling zone defined by a plasma cooling passageway, to a plasma accelerating zone defined by a narrowed passageway that expands into a plasma/particle confining zone for the discharge of material from the apparatus. The narrowed passageway of the apparatus is cooled, and the powder material to be applied by the apparatus is introduced into the plasma stream along the cooled, narrowed passageway. To apply thermal spray coatings of increased hardness to a substrate, the ratio of the length of the plasma/particle confining zone relative to the diameter of the plasma/particle confining zone (the "L/D" ratio) is increased from the more conventional value of about 5:1, preferably to a ratio in a range of from 7:1 to 16.5:1, for use with coating materials including WC--Co, Cr.sub.3 C.sub.2 --NiCr and Cr.sub.3 C.sub.2. Ratios of from 10:1 to 13:1 have been found to achieve a particularly desirable result. Also the method and the coatings obtained.

The present invention relates generally to the thermal spraying of powdered materials, as well as their application to surfaces as protective coatings.
A variety of thermal spray coatings have long been used to protect various components. A principal variety of thermal spray coatings to which the subject matter of the present invention pertains includes plasma sprayed coatings, although the improvements of the present invention will also pertain to other coatings and processes such as high velocity oxy-fuel (HVOF), having similar uses and properties. Plasma spray processes have been used to apply many different types of coatings to a variety of substrates, and find utility in numerous industries. One such application is responsive to conditions where a high degree of stress and wear is prevalent. In such a case, protective coatings containing carbides are often used. For example, the mid-span stiffeners used in the fan blades of aircraft gas turbine engines are commonly coated with a highly wear resistant tungsten carbide-cobalt (WC--Co) coating.
Popular techniques for the application of such coatings would include plasma spraying and high velocity oxy-fuel spraying. In the implementation of such coatings, hardness is often a factor of primary concern. However, both plasma sprayed coatings and high velocity oxy-fuel coatings have proven to be limited in their ability to meet the minimum mechanical property requirements for certain applications, particularly the requirements for minimum hardness.
In the practice of such processes, the current trend in the industry has been to develop processes that increase particle velocity and deposition rates. For example, an article by M. L. Thorpe and H. J. Richter, entitled "A Pragmatic Analysis and Comparison of the HVOF Process", Proceedings of the International Thermal Spray Conference & Exposition, Orlando, Fla. (May 28 to Jun. 5, 1992), at pages 137-147, discusses the increase of particle velocities in thermal spray processes. However, these known techniques have remained somewhat limited in terms of the overall hardnesses which could be achieved.
U.S. Pat. No. 5,082,179 (Simm et al.), U.S. Pat. No. 4,741,286 (Itoh et al.) and U.S. Pat. No. 4,236,059 (McComas et al.) disclose flame sprayed coatings applied using a plasma spray process. Simm et al. disclose relatively low velocity, low temperature spray methods, which are generally not suited to severe wear and erosion applications. Itoh et al. similarly disclose coatings applied with a low rate plasma gas flow. Generally speaking, the disclosed systems provide no specific guidance relative to the development of plasma sprayed coatings of a hardness commensurate with many present applications.
U.S. Pat. No. 5,330,798 (Browning) discloses flame sprayed coatings applied with a high velocity oxy-fuel spray process. The disclosed process uses the kinetic energy of impacting particles to obtain dense coatings. However, again, the resulting coatings are not of a hardness commensurate with many present applications.

Method and apparatus for applying coatings using a nozzle assembly having passageways of differing diameter


The invention relates to a method and to a modulator for modulating signals. The signals are to be transmitted by a device in packets via an air interface. Each packet is supposed to comprise at least one entity of at least two different entities, which different entities are employed for transmitting signals representing different kinds of information. In order to enable a higher data rate, signals that are to be transmitted in at least one of said different entities are modulated with a first set of values of at least one modulation parameter of a selected modulation scheme. Further, signals that are to be transmitted in at least one other of said different entities are modulated with a second set of values of said at least one modulation parameter, said second set of values comprising less values than said first set of values.

Transmitting modulated signals which are arranged in packets via the air interface is known for example for short-range radio links established between different devices. Short-range radio links can be employed for connecting devices located close to each other without requiring connections by cords.
Short-range radio links between electronic devices have been specified in the global "Specification of the Bluetooth system", v1.1, Feb. 22, 2001. The specification is aimed at providing a standard for low complexity low-cost wireless connections between portable and/or fixed devices, in particular devices which are located within a range of 10 meters to each other. An example for the employment of such a Bluetooth™ short-range radio link would be a wireless connection between a laptop or mobile phone and a printer.
Transmissions between devices as defined by Bluetooth™ are based on a frequency hopping system using 79 channels with 1 MHz each in the 2.45 GHz ISM (Industrial, Scientific and Medical) band. The data is transmitted in packets, and each packet is transmitted on a different hop frequency. In the specification, three different packet structure are defined. A first structure includes only an access code of 68 bits, a second structure includes an access code of 72 bits and a header entity of 54 bits, while a third structure includes an access code of 72 bits and a header entity of 54 bits and a payload entity ranging from zero to a maximum of 2745 bits. Each packet starts with the access code, which is used inter alia for synchronization purposes.
Any device can request a link to other devices, the requesting device being a master and the respective other devices being slaves. Connections can be point-to-point between one master and one slave, or point-to-multipoint between one master and several slaves sharing the same channel. A channel is defined by the hopping sequence used, whereas the hopping sequence is determined by the Bluetooth™ device address of the master. Two or more devices sharing the same channel form a piconet. All slaves in one piconet are synchronized to the system clock of the master. To this end, in a receiver of a slave a sliding correlator correlates against the access code of a received packet and triggers when a threshold is exceeded. This trigger signal is used to determine the receive timing.
According to the current Bluetooth™ specification, signals are modulated for transmission using a GFSK (Gaussian Frequency-Shift Keying) modulation scheme. More specifically, it is requested that a bit of '1' is represented by a positive frequency deviation from the transmit frequency, and that a bit of '0' is represented by a negative frequency deviation from the transmit frequency. It is further requested that the minimum absolute frequency deviation achieved by a bit sequence of '1010' is at least 80% of the absolute frequency deviation achieved by a bit sequence of '00001111'. With the requested modulation scheme, a gross data rate of 1 Mbit/s, corresponding to a symbol rate of 1 Ms/s, can be achieved.
It is a declared aim to at least double the currently specified medium data rate at low cost to a gross data rate of 2 Mbit/s or higher. It is important that a higher data rate system is fully backward compatible with the current specification, in order to ensure that current devices are also capable to operate as a slave in piconets that comprise higher data rate devices.
A further request for higher data rate devices relates to the synchronization of devices in a piconet. Since in the current piconets, the synchronization of a device can be based on the access code transmitted by the respective master in the first entity of each packet, it should be ensured that current devices can also decode the access code of transmissions employing a higher data rate. Preferably, a current Bluetooth™ device should also be able to decode the header of received packets, the header comprising e.g. an indication of the slave to which the packet is addressed, an indication of the type of the packet and thus an indication of the length of the packet.
Different proposals were made to increase the medium data rate for Bluetooth™ transmissions. In order to achieve a simple backward compatibility, all proposals are based on a modulation scheme similar to the scheme defined in the current specification for modulating access code and header. Only the payload is supposed to be modulated with a different modulation scheme enabling a higher data rate. Because of the different modulation schemes employed in all these proposals for access code and header on the one hand and payload on the other hand, the modulation scheme has to be changed between the modulation of the access code and the header and the modulation of the higher data rate payload. A change of the modulation scheme, however, requires a guard time between the modulation of the header and the payload. With some modulation schemes, even a new synchronization entity is required for symbol re-synchronization. Both, the guard time and a new synchronization, add complexity to the system and reduce the total achievable data rate.
In order to provide a comprehensive backward compatibility, a demodulator according to the invention should further comprise second demodulating means for demodulating other received signals which were modulated with a second modulation scheme. If this second modulation scheme is e.g. the GFSK modulation required by the current Bluetooth™ specification, the demodulator is able to demodulate signals modulated according to the invention and equally signals modulated by a current Bluetooth™ device.
In U.S. Pat. No. 5,706,428, it is proposed that the initial portion of a message is transmitted in a wireless data communication system at a first predetermined one of a first plurality of data rates and that the data portion of the message is transmitted at a selected one of a second plurality of data rates. For each of the data rates, another modulation scheme is used.
An equally proposed demodulator is suited for demodulating modulated signals originating from the proposed modulator. Such a demodulator comprises therefore demodulating means for demodulating received signals with a demodulation scheme corresponding to the selected modulation scheme, and processing means for processing the demodulated signals for regaining the original signals before modulation. The processing depends on the set of values of the at least one modulation parameter of the selected modulation scheme used for modulation. A method for demodulating signals comprises corresponding steps.
Further proposed is a device comprising the proposed modulator and/or the proposed demodulator and a wireless communications network comprising at least one such device.
The invention proceeds from the idea that a single modulation scheme can be employed for transmitting signals with different bit rates. This is achieved according to the invention by applying on the one hand a first set of the values of at least one parameter of a selected modulation scheme on signals that are to be modulated, and on the other hand a second set of these values. If both sets comprise different numbers of values of said at least one parameter, different entities of a packet can be modulated with different bit rates without requiring a guard time between the different entities for switching the modulation scheme and without requiring a re-synchronization. If the modulation scheme and the two sets of values of modulation parameters are selected suitably, the signals modulated with the set comprising less values can then be demodulated for example by demodulators not supporting a demodulation of signals modulated with a larger set of values. Since the invention moreover results only in a small increase of complexity in a modulator, demodulator, device or communications system, it can further be realized at low costs.
Preferred embodiments of the invention become apparent from the dependent claims.
The first set of values of the at least one modulation parameters preferably comprises all values of the at least one modulation parameter of the selected modulation scheme. This enables a maximum bit rate for the signals modulated with the first set of values. Alternatively, the first set of values can comprise only a subset of all values of the at least one modulation parameter, as long as it is ensured that the first set comprises more values than the second set of values.
The invention can be employed in particular, though not exclusively, for short-range radio links, like Bluetooth™.
In a preferred embodiment of the invention, a packet can consist of an entity with synchronization information and/or an entity with payload data. It is proposed that the payload data is modulated with the first set of the selected modulation scheme, in order to enable a higher data rate for transmission. At the same time it is proposed to modulate the synchronization information with the second set of values, resulting in a second reduced transmission rate, in order to allow also devices not supporting a demodulation of signals transmitted with the higher data rate to demodulate at least the synchronization part of a packet.
In case the invention is employed for a system employing a structure of packets similar to the Bluetooth™ system, it is proposed that the access code entity and, if present, the header entity of each packet are modulated with a reduced modulation scheme, while the payload entity, if present, is modulated with the first set of the values of modulation parameters of the selected modulation scheme. A possibility to demodulate in addition to the access entity also the header entity of each packet can be of interest for receiving devices, since the header entity indicates for example the length of the respective packet.
In a further preferred embodiment of the invention, the selected modulation scheme is a π/4-DQPSK modulation scheme (Differential Quadrature Phase Shift Keying), which employs +135°, +45°, −45° and −135° phase changes for modulation. If all phase changes are allowed, i.e. if the entire set of this modulation scheme is employed, a higher data rate is achieved than e.g. with the GFSK modulation scheme (Gaussian Frequency Shift Keying) employed according to the current Bluetooth™ specification. The second set of values when using this scheme used for modulating the access code and the header could then include e.g. only ±45° phase changes. This subset leads to the same data rate for the access code and the header of a packet. In the whole, the medium gross data rate is thus higher than with the GFSK modulation scheme of the Bluetooth™ specification.
Preferably, a π/4-DQPSK modulation scheme employs a raised cosine filter for pulse shaping with a roll-off factor of 0.8. This ensures that signals modulated with the reduced modulation scheme using only phase changes of ±45° can be demodulated with current Bluetooth™ devices. It is to be noted, though, that the selection of +450 phase changes for a reduced modulation scheme, as well as the use of a raised cosine filter with a roll-off factor of 0.8 are only to be understood as example which can be varied in any suitable way.
In a π/4-DQPSK modulation scheme, for each phase change a set of two bits is mapped to one of the four available phase changes. In order to restrict the changes to only two possible phase changes, one bit of each pair of bits can be frozen to either '0' or '1'. Thus, only one of the two bit of each set of bits influences the mapping, leading to a reduced mapping to only two of four available phase changes. With such an approach, a gross data rate of up to 2 Mbit/s, corresponding to a symbol rate of 1 Ms/s, and a maximum user data rate of 1.4 Mbit/s can be achieved for connections employing the currently defined Bluetooth™ payload types. The maximum user data rate is twice that of the current Bluetooth™ user data rate.
Instead of a π/4-DQPSK modulation scheme also other modulation schemes can be employed. In particular, more complex modulation schemes than QPSK can be selected. An 8PSK modulation scheme would be suited for instance for a payload modulation in some cases which require a high speed transmission speed but only a short transmission distance. In a Bluetooth™ system, for instance, the access code and the header can then be modulated in a similar manner as proposed for DQPSK, thus a synchronization of current devices to transmitted packets remains possible. With more complex modulation schemes, even higher gross medium data rates than 2 Mbit/s can be achieved easily.
A control signal can be employed for selecting the beginning of the payload and thus for switching from using only a subset of the modulation scheme to using the whole modulation scheme.
In another embodiment of the invention, fixed values are added already in the baseband to the signals which are to be modulated with the first set of values. More specifically, bits of '0' and/or '1' are added in the baseband to the regular bits. Then, the required change between a modulation with the second set of values and a modulation with the first set of values is achieved automatically in the modulator.
Preferably, the modulation is based on a lookup table, according to which signals that are to be transmitted are mapped to different values for the modulation, e.g. to the different phase changes employed in a π/4-DQPSK modulation scheme.
Advantageously, a modulator according to the invention is moreover able to support two different modulation schemes. These two modulation schemes can then be applied to signals that are to be transmitted alternatively, depending on the desired connection. They can also be applied in parallel, the currently appropriately modulated signals then being selected for transmission. If employed in a Bluetooth™ system, the second modulation scheme should be the GFSK modulation scheme defined in the current Bluetooth™ specification.
In case two modulation schemes are supported, a first lookup table can be provided for a mapping according to the invention, and a second lookup table can provided for a mapping for a conventional modulation scheme. A new modulator supplied with these two lookup tables is then able to modulate signals that are to be transmitted with the modulation scheme available at another device with which it wants to communicate.

Modulation of signals for transmission in packets via an air interface


A combine including an improved HVAC control system. The frame of the combine supports an operator cab, a harvesting head and the other operational systems of the combine. The control system includes an operator control and a heat exchanger located in the cab. The control system also includes at least one sensor disposed to sense at least one of an ambient air temperature, a cab air temperature and solar loading, and to produce at least one sensed signal representative thereof. The operator control is configured to produce a set-point signal representative of a desired cab air temperature. An interface circuit is electromagnetically coupled to the valve assembly, the operator control, and the at least one sensor. A cooling coil may also be located in the cab, wherein the interface circuit is electromagnetically coupled to the associated coolant compressor. The interface circuit produces a temperature differential based upon a comparison of the set-point signal to the at least one sensed signal and applies the electrical control signals to the valve, compressor and blower based upon the temperature differential to achieve the desired cab air temperature and minimize cab air temperature oscillations.

Operation of off-road and agricultural vehicles is simplified by locating operator controls which require viewing near the line of sight of the operator. As a result, heating and cooling controls, and the energy transfer mechanisms associated therewith (heating and cooling heat exchangers) in vehicles such as combines have conventionally been located at the center and top of the operator cab near the line of sight of the operator. In particular, the control knobs, the blower, and the heat exchangers are typically at the top and center of the cab. In this configuration, the blower and heat exchangers are positioned at the same location as the control knobs to simplify the mechanical link between the control knobs and the heat exchanger valves. Another reason the blower and heat exchangers are located at the top center of the cab is to provide a relatively efficient use of cab space.
Despite the advantages of locating the heating controls and associated heat transfer devices at the top and center of a cab, there are some disadvantages. One such disadvantage is that the cost of providing water and refrigerant lines to the coils is relatively high. More specifically, the hot water source (e.g., engine) and refrigerant source (e.g., compressor on the engine) in a combine are relatively distant from the top and center of the cab. However, if the heat exchangers and associated valves are displaced from the control knobs, the routing of the mechanical link therebetween becomes difficult and expensive. Another disadvantage caused by locating the heating coil at the top and center of the cab is the inability to effectively heat the lower portions of the cab, such as at the operator's feet.
U.S. Pat. No. 5,538,472 for "Agricultural Vehicle Cab Temperature Control System" discloses an agricultural vehicle such as a combine in which the heat exchangers are relocated from the typical location adjacent the heating controls at the top and center of the operator cab to a location such as below the operator seat, with the heating controls electromagnetically linked to the heat exchangers. This spacial arrangement allows the conduits for heat transfer fluid to be simplified because the heat exchangers are located closer to the heat source than in the prior art systems.
Operator comfort within the cab of an agricultural vehicle such as the one described in the above-identified patent may be affected by a number of external factors. For example, changes in ambient air temperature can lead to undesired changes in the cab air temperature, which decreases operator comfort. In addition, operator comfort in the cabs of such vehicles can be adversely influenced by solar loading on sunny days. This results from the functional cab design of such vehicles which requires large front and side windows to maximize visibility to crop as it enters the machine and good visibility to the sides. These front and side windows may extend from the floor to headliner, but behind the cab there may be only a small window to allow visibility into a grain tank which typically blocks sunlight from the rear. Thus, operator comfort in such cabs is significantly influenced by the position of the sun and the direction of travel. More particularly, the operator can feel the radiant heat from sunlight when traveling towards the sun or at right angles to the sun but does not feel it when traveling away from the sun.
In systems requiring manual setting of the heat energy output of the heat exchangers, operators may find it difficult or even impossible to continually monitor and change the settings as needed to compensate for such external influences and maintain a desired cab air temperature. Accordingly, it would be desirable to automatically control the amount of heating or cooling and the fan speed to maintain a constant, desired temperature in the cab without need for operator intervention.

Agricultural vehicle cab automatic temperature control system


An improved cathode comprises a cone-shaped emitter with a carbon-based coating applied to the emitter cone surface, in which there is a narrow annular gap between the emitter body and the carbon coating. The gap prevents direct contact between the carbon coating and the crystalline emitting material, thereby preventing damaging interactions and extending the useful lifetime of the cathode.

1. Field of the Invention
The invention generally relates to improvements in thermionic cathodes with carbon-coated surfaces. In particular, the invention provides a cathode in which a gap is present between the carbon coating and the cathode's surface, thereby preventing interaction of carbon and the crystalline emitter material which would otherwise cause damage to the cathode.
2. Background of the Invention
Lanthanum hexaboride (LaB6), cerium hexaboride (CeB6), hafnium carbide (HfC), in sintered or crystalline form, are used as electron sources, or emitters, in various electron-beam tools (e.g. lithographic tools, scanning electron microscopes (SEMs), transmission electron microscopes (TEMs, etc). A typical emitter is tapered, or cone-shaped, with a specified tip or truncation size and cone angle, as shown in FIG. 1A.
The tip (truncation) may be flat or spherical, with diameter from 5 to 100 μm and a cone angle of from 60 to 110 degrees, depending on the application. These cathodes, however, have two built-in disadvantages: Disadvantage 1: at operating temperatures (1650 to 1900 K), emitter material evaporates, and tip size continuously diminishes, which limits the cathode's useful life time. Disadvantage 2: under operating conditions, the electron beam is formed by electrons emitted from both the tip and the cone surface. Electrons emitted from the cone surface constitute up to 65% of the total emission current, but cannot be used in well-focused beams (Ref. 1).
It is thus advantageous to suppress or eliminate material evaporation and electron emission from the cathode cone surface. This may be done, for example, by coating the cone surface with carbon. (Ref. 2). A cross-sectional view of a cathode with a carbon coated cone surface is shown in FIG. 1B. At cathode operating temperatures (e.g. 1650 to 1900 K), the carbon coating's evaporation rate is very low, e.g. ˜1000 times lower than that of LaB6 or CeB6, with a vapor pressure at just 10−10 Torr, which is practically negligible. Hence, the coating does not change its dimensions during the cathode lifetime (about 3000 hrs). In other words, carbon-coated cathodes (e.g. carbon-coated K—LaB6, K—CeB6, and K—HfC) exhibit neither electron emission nor carbon evaporation, and the inherent disadvantages of LaB6 cathodes discussed above are eliminated by the coating
Nevertheless, carbon coatings have disadvantages. Such cathodes have a limited lifetime, caused by both emitter erosion and loss by evaporation, and this loss is caused, in part, by chemical interactions between the carbon coating and the LaB6/CeB6 cathode material. This can be observed in the photograph shown in FIG. 1C, which shows the flat surface of a cone's emitting surface surrounded by the adjacent carbon coating. As can be seen, the edges of the emitting surface of the cone which are in contact with the carbon coating appear to be damaged (e.g. pitted and/or etched). In fact, these areas of the emitting surface are compromised and are no longer capable of efficiently emitting electrons in a focused manner. Thus, in spite of the advantages conferred by the carbon coating, the useful lifetime of the cathode has been attenuated by the contact with the carbon coating.
There is a need in the art to develop alternative ways of extending the lifetime of cathodes. For example, there is a need to develop new cathode coatings that exhibit the positive attributes of carbon coatings, but which do not have the problems associated with carbon coatings.

High-brightness, long life thermionic cathode and methods of its fabrication


A modular knee prosthesis system includes a femoral component having a stem, a plurality of different sizes of sleeves mountable on the stem, and a plurality of different sizes of augments mountable on the femoral component. The system is modular, and provides the surgeon with the option of distally offsetting the joint line by selecting the size of sleeve that will provide the desired joint line. The different sizes of sleeves have different axial lengths but share a common geometry along a substantial part of their lengths so that the same bone cavity will accept multiple sizes of sleeves.

The knee joint basically consists of the bone interface of the distal end of the femur and the proximal end of the tibia. Appearing to cover or at least partially protect this interface is the patella, which is a sesamoid bone within the tendon of the long muscle (quadriceps) on the front of the thigh. This tendon inserts into the tibial tuberosity and the posterior surface of the patella is smooth and glides over the femur.
The femur is configured with two knob like processes (the medial condyle and the lateral condyle) which are substantially smooth and which articulate with the medial plateau and the lateral plateau of the tibia, respectively. The plateaus of the tibia are substantially smooth and slightly cupped thereby providing a slight receptacle for receipt of the femoral condyles.
When the knee joint is damaged whether as a result of an accident or illness, a prosthetic replacement of the damaged joint may be necessary to relieve pain and to restore normal use to the joint. Typically the entire knee joint is replaced by means of a surgical procedure that involves removal of the surfaces of the corresponding damaged bones and replacement of these surfaces with prosthetic implants. This replacement of a native joint with a prosthetic joint is referred to as a primary total-knee arthroplasty.
On occasion, the primary knee prostheses fails. Failure can result from many causes, including wear, aseptic loosening, osteolysis, ligamentous instability, arthrofibrosis and patellofemoral complications. When the failure is debilitating, revision knee surgery may be necessary. In a revision, the primary knee prosthesis is removed and replaced with components of a revision prosthetic knee system.
Knee implant systems for both primary and revision applications are available from a variety of manufacturers, including DePuy Orthopaedics, Inc. of Warsaw, Ind. DePuy and others offer several different systems for both primary and revision applications. For example, DePuy Orthopaedics offers the P.F.C. SIGMA® Knee System, the LCS® Total Knee System, and the S-ROM Modular Total Knee System. These orthopaedic knee systems includes several components, some appropriate for use in primary knee arthroplasty and some appropriate for use in revision surgery.
DePuy Orthopaedics also offers other orthopaedic implant systems for other applications. One such system is the LPS System. The LPS System is provided for use in cases of severe trauma and disease. In such cases, the trauma or disease can lead to significant amounts of bone loss. The LPS System provides components that can replace all or significant portions of a particular bone, such as the femur. The DePuy LPS System is described more fully in U.S. patent application Ser. No. 10/135,791, entitled "Modular Limb Preservation System", filed Apr. 30, 2002 by Hazebrouck et al. (U.S. Pat. Pub. No. 2003-0204267), which is incorporated by reference herein in its entirety.
In some patients, the metaphysis of the bone near the joint presents cavitary defects that are not completely filled by standard knee implants. The presence of such metaphyseal defects can result in loosening of the prosthetic implant over time, compromising the stability of the prosthetic implant and frequently requiring revision of the prosthetic implant.
To fill metaphyseal cavitary defects, knee systems with modular metaphyseal sleeves have been provided. Such sleeves are illustrated, for example, in: U.S. Pat. Pub. No. 2010/0114323, entitled "Knee Prosthesis Kit with Winged Sleeves and Milling Guide;" U.S. Pat. Pub. No. 2006/0030945A1, entitled "Modular Orthopaedic Implant System With Multi-Use Stems;" U.S. Pat. No. 7,799,085, entitled "Modular Implant System With Fully Porous Coated Sleeve;" U.S. Pat. No. 7,291,174, entitled "Prosthetic Tibial Component With Modular Sleeve;" U.S. Pat. No. 6,171,342, entitled "Medical Fastening System;" U.S. Pat. No. 5,824,097, entitled "Medical Fastening System;" U.S. Pat. No. 5,782,921, entitled "Modular Knee Prosthesis;" and U.S. Pat. No. 4,634,444, entitled "Semi-Constrained Artificial Joint." Such sleeves have been used in commercially available prosthetic knee implant systems, such as the P.F.C. SIGMA.® Knee System, the LCS® Total Knee System, the S-ROM Modular Total Knee System and the LPS System, all available from DePuy Orthopaedics, Inc. of Warsaw, Ind.
Modular sleeves have also been used in hip implant systems, as illustrated, for example, in: U.S. Pat. No. 6,264,699, entitled "Modular Stem and Sleeve Prosthesis;" and U.S. Pat. No. 4,790,852, entitled "Sleeves for Affixing Artificial Joints to Bone." Such hip sleeves have been used in commercially available prosthetic hip implant systems, such as the S-ROM hip systems, available from DePuy Orthopaedics, Inc. of Warsaw, Ind.
The disclosures of all of the above patent applications and patents are incorporated by reference herein in their entireties.
In knee systems with modular metaphyseal sleeves, the conventional shape of many of the sleeves is generally an elliptical cone with a large ellipse profile close to the joint line tapering down to a smaller elliptical or circular profile at the termination of the component distal to the joint line. Generally, the sleeves have a terraced or stepped outer surface and an inner channel for frictional fixation to another component. This geometry fills cavitary defects in the metaphysis, allows for a wider surface area for load transfer through the joint and provides rotational stability for the articulating components of the prosthesis.
The outer surface of the sleeve is supported by solid bony structure or the bone bed. In the case of the distal femur, patient anatomy and the condition of the bone, particularly in a revision surgery, may require that the distal femur be resected to a more proximal level. Implanting a prosthetic distal femoral component and sleeve at this more proximal level may elevate the joint line (that is, the line defined by the articulation of the articular surfaces of the distal femoral component and proximal tibial component). Elevation of the joint line may adversely affect performance of the prosthetic knee system: the positions of the collateral ligament attachments to the femur relative to the joint line may impact knee kinematics, the articulation of the patella against the femoral component will be impacted, and the function of the extensor mechanism will also be impacted.
Prosthetic knee implant systems have commonly included femoral augments for use on the distal and posterior bone-facing surfaces of the femoral implant components. Examples of such augments are disclosed in U.S. Pat. Nos. 6,005,018 and 5,984,969, which are incorporated by reference herein in their entireties. Such components serve to augment the inferior and posterior portions of the femoral component to add additional thickness to compensate for the lack of sufficient boney tissue, allowing the joint line to be distalized. However, with the femoral component so distalized, the metaphyseal sleeve used with the femoral component may no longer be optimally seated on a healthy bone bed. To compensate, surgeons may sometimes opt to use a larger size of metaphyseal sleeve. Because of differences in the geometries of differently-sized metaphyseal sleeves, changing to a larger size requires that the surgeon prepare the bone cavity a second time so that the cavity will accept the geometry of the larger size of metaphyseal sleeve.
Accordingly, a need exists for a knee prosthesis system that allows the surgeon the flexibility to optimize the position of the joint line while also allowing for a metaphyseal sleeve to be efficiently and optimally positioned on a healthy bone bed.

Femoral knee prosthesis system with augments and multiple lengths of sleeves sharing a common geometry


A reworkable epoxy underfill is provided for use in an electronic packaged system which incorporates an integrated circuit, an organic printed wire board, and at least one eutectic solder joint formed therebetween. An exemplary embodiment of the encapsulant includes: a cycloaliphatic epoxide; an organic hardener; and a curing accelerator; wherein said cycloaliphatic epoxide includes a carbonate or carbamate group. The encapsulant can also include a filler, such as a silica filler. A method is also provided for forming the aforementioned reworkable epoxy underfills.

This invention relates to thermally reworkable epoxy resin compositions, and more particularly to thermally reworkable carbamate or carbonate epoxide resin compositions which degrade at temperatures significantly lower than traditional cycloaliphatic epoxy resins.
In the field of electronic packaging and, in particular, the field of integrated circuit (IC) chip interconnection, the desirability of incorporating high input/output (I/O) capability and short IC interconnects, among others, typically has led to the adoption of the flip-chip technique of IC chip interconnection. Generally, the flip-chip technique involves electrically interconnecting an IC chip and a substrate with the use of solder joints which are disposed between the IC chip and the substrate.
As initially practiced, the flip-chip technique oftentimes utilized relatively high cost materials, such as high lead solder and ceramic substrate. However, the desire to reduce costs has prompted the use of less expensive materials, such as flip-chip on board (FCOB), which typically utilizes eutectic solder and organic printed wiring board (PWB). While reducing material costs, the use of FCOB packaged systems has accentuated the problem of coefficient of thermal expansion (CTE) mismatch between the IC chip and the organic substrate of the FCOB, particularly when large IC chips and fine pitch, low profile solder joints are utilized. Due to the CTE mismatch between silicon IC chips (2.5 ppm/xc2x0 C.) and organic substrates, i.e., FR-4 PWB (18-24 ppm/xc2x0 C.), temperature cycle excursions experienced by the FCOB generate tremendous thermo-mechanical stress at the solder joints and, subsequently, can result in performance degradation of the packaged system.
It is also known in the prior art to fill the spaces or gaps remaining between an IC chip and substrate which are not occupied by solder with an underfill composition. The undefill is an adhesive, such as a resin, that serves to reinforce the physical and mechanical properties of the solder joints between the IC chip and the substrate. The underfill typically not only provides fatigue life enhancement of a packaged system, but also provides corrosion protection to the IC chip by sealing the electrical interconnections of the IC chip from moisture, oftentimes resulting in an improvement in fatigue life of ten to over one hundred fold, as compared to an un-encapsulated packaged system.
Heretofore, cycloaliphatic epoxies, typically combined with organic acid anhydrides as a hardener, have been used in flip-chip packaged systems as an underfill. This is primarily due to the low viscosity of cycloaliphatic epoxies prior to curing, as well as their acceptable adhesion properties after curing. Other epoxies such as bisphenol A or F type or naphthalene type can also be used in the underfill formulations. Additionally, silica has been utilized as a filler in these underfill formulations, i.e., up to 70% (by weight), in order to lower the CTE of the epoxy resin. By way of example, the material properties represented in Table 1 typically are exhibited by typical prior art epoxy underfill compositions.
Frequently, defects in a chip or circuit board are not discovered until after assembly of an electrical component using an underfill adhesive. Heretofore, it has generally been commercially impractical to separate and clean the chip and/or board so that the non-defective components can be reused. This results in increased production costs due to the waste of otherwise usable components. An effective way to address this problem is to make the flip-chip devices reworkable under certain conditions.
One method which has been developed in an attempt create a reworkable flip-chip device has been to incorporate a non-stick release coating on the boundary surface between a chip and a substrate. For example, U.S. Pat. No. 5,371,328 discloses a reworkable flip-chip type of circuit module using a non-stick release coating on all surfaces intermediate of the chip and the substrate. While this non-stick release coating may be suitable in some applications, it is likely that the use of such a release coating may reduce the adhesion of all the interfaces including those of the underfill to chip and underfill to substrate. These adhesions are important to the reliability of the flip-chip interconnections. Accordingly, this approach is not ideal for use in flip-chip applications.
Another approach to providing a reworkable flip-chip interconnection is to use a reworkable underfill. Presently, the materials that are undergoing development for reworkable underfills can be classified into two categories: chemically reworkable underfills and thermally reworkable underfills.
Chemically reworkable underfills generally require the use of harsh acids and/or bases. For example, U.S. Pat. No. 5,560,934, issued to Afzali-Ardakani et al., discloses epoxy compositions that are soluble in an organic acid after curing. Utilizing relatively strong chemicals such as acids (or bases) during reworking, however, oftentimes leads to a messy, time-consuming rework process. Additionally, it has been found that the use of chemicals during the rework process typically makes localized repair of a packaged system difficult and, sometimes, impossible. Therefore, it is believed that use of a thermal rework process would avoid these problems and offer the possibility of a quick, clean, and localized rework process.
U.S. Pat. No. 5,659,203, issued to Call et al., discloses a reworkable flip-chip module utilizing a specially defined thermoplastic resin as an encapsulant. The thermoplastic resin, such as polysulfone, polyetherimide, etc., possesses a high glass transition temperature (Tg), e.g., 120xc2x0 C. less than Tg less than 220xc2x0 C., and must be either dissolved in a solvent or heated above its melting point during the encapsulation process. Therefore, use of these thermoplastic resins as encapsulants for FCOB applications may be undesirable, since such applications typically require an underfill which is free of solvent and in liquid form during the encapsulation process, and typically require keeping the packaged system at lower temperatures in order to maintain the integrity of the eutectic solder which is utilized with the organic PWB.
U.S. Pat. Nos. 6,197,122 and 5,948,922, issued to Ober et al., disclose thermally reworkable underfill formulations based on thermally decomposable epoxies containting a secondary or tertiary oxycarbonyl (ester) moiety. However, a secondary or tertiary oxycarbonyl moiety typically can easily be cleaved by weak acid or base, and is sensitive to moisture. Also the epoxies containing a secondary or tertiary oxycarbonyl moiety typically have higher moisture uptake than a standard epoxy. All these facts indicate that epoxies containing a secondary or tertiary oxycarbonyl moiety might not be suitable for underfill application where high reliability is required.
Thus, it can be seen that none of the prior art methods are ideally suited for use as an underfill to bond chip and substrate to allow fast and efficient rework of FCOB devices without sacrificing the reliability of the devices. Therefore, it is desirable to provide an underfill composition that will not negatively affect the overall performance of the assembly, while still allowing cost effective and efficient rework.
Accordingly, it is an object of this invention to provide a polymeric composition that has properties suited to use as an underfill while also offering thermal reworkability. The present invention is focused on epoxy base materials because epoxy base materials have desirable properties for use as an underfill and are the only materials that have been proven to provide flip-chip devices with acceptable reliability.
Most epoxy materials are thermosetting compositions and are difficult or impossible to remove after curing. The present invention overcomes this limitation by developing new diepoxides that contain thermally degradable groups within their structures and using these new diepoxides in the epoxy formulations to make the thermoset network degradable at a desired temperature. This makes the new epoxy formulations reworkable. Moreover, these thermally degradable groups have good properties such as high moisture resistance, high chemical resistance and low moisture uptake so that they are suitable for underfill application. This improvement is advantageous in flip-chip application of epoxy compositions where epoxy materials are used as the underfill to reinforce the solder joints. Removal of the epoxy allows replacement of defective devices, saving the cost of discarding other valuable components in a microelectronic assembly.
There are two ways of developing reworkable epoxy base materials. One is to develop new epoxies that decompose at rework temperature. The other is to develop additives to add into the existing epoxy formulations that have previously been found suitable for use as underfill encapsulants. The present invention focuses on the first category and uses thermally degradable epoxies containing integral thermally cleavable groups that decompose at rework temperatures. The second category is the subject of U.S. Pat. No. 6,172,141.
The thermally cleavable groups of the present invention have been selected to meet the following criteria:
1. The cleavable groups should be sufficiently stable to permit the epoxy network to perform its function in a specific application;
2. The cleavable groups should be inert to the curing reaction of the epoxy network;
3. The cleavable groups should not adversely affect the overall properties of the epoxy network;
4. The cleavable groups should decompose quickly at elevated temperature so that they break down the structure of the epoxy network, leading to its easy rework.
5. The link should be stable in the environment to which the cured epoxy will be exposed.
6. The synthesis of the epoxides containing the cleavable link should be simple, with high yield, and cost effective.
The present invention discloses carbonate and carbamate epoxides which have been found to meet the above criteria. After introduction into the epoxy structure, the carbamate and carbonate groups do not significantly interfere with epoxy curing, nor do they adversely affect epoxy properties including Tg, modulus, CTE, adhesion. However, the existence of these groups inside the epoxy structure reduces the epoxy decomposition temperature from 350xc2x0 C. to as low as 200xc2x0 C. Optimal rework temperatures for flip-chip devices are generally between 200xc2x0 C. and 250xc2x0 C. because the eutectic solder reflow temperature is within this temperature region. Therefore, these two groups may be suitable for use in applications needing an epoxy which is reworkable around solder reflow temperature.
More particularly, the present invention is directed to a thermally reworkable epoxy composition for encapsulating and protecting an electronic device or assembly. The thermally reworkable epoxy composition includes the cured reaction product of: a cycloaliphatic epoxide containing either a carbonate or a carbamate group; an organic hardener; and a curing accelerator. The present invention is also direct to a method of protecting, encapsulating, reinforcing, assembling, or fabricating a device or a chemical product with a cured epoxy composition which is thermally reworkable, wherein the epoxy composition includes the reaction product of: a thermally degradable cycloaliphatic epoxide; an organic hardener; and a curing accelerator.

Thermally degradable epoxy underfills for flip-chip applications


The present invention relates to a method for routing at least a data packet in a wireless sensor network (10), the wireless sensor network (10) comprising: at least a source node (S) that is configurable to transmit at least a data packet; at least a destination node (D) that is configurable to receive the data packet transmitted by the source node (S), and interconnectable network nodes (si) between the source node (S) and the destination node (D) that are configurable to receive and forward the data packet, the method comprising the steps of: operating the network nodes (si) according to a sleep-active schedule comprising at least a sleep mode and an active mode, and configuring the network nodes (si) to have information on their own geographic location and the geographic location of the destination node (D), the method further comprising the steps of: dividing the wireless sensor network (10) into a plurality of disjoint areas (A0, AM-1, A1, A2) that are separated by boundaries; separating each area (A0, AM-1, A1, A2) into at en least two regions, the regions being an inner boundary region (I), a central region (C) and an outer boundary region (O); selecting forwarding nodes out of the network nodes (si) to route the data packet from the source node (S) to the destination node (D), such forwarding nodes being selected on the basis of their geographic location relative to the destination node (D) and the network nodes being synchronized relative to each other, and configuring the sleep-active schedule such that only those forwarding nodes that are selected to route the data packet in a given time window are operable in the active mode and all the other network nodes (si) are operable in the sleep mode.

Wireless sensor networks have the potential for diverse application for example, in building surveillance, disaster prevention and environmental monitoring. A wireless sensor network is made up of a relatively large number of nodes, generally referred to as network nodes, that are located in and spread over a geographic area corresponding to that in which the wireless sensor network is implemented. The network nodes may typically be inexpensive, battery-powered, electronic devices, such as sensors, for example, with reduced capability to store, process and/or analyse data. The network nodes are generally applied to fulfill at least two challenging tasks: firstly, to continuously monitor the status of a physical phenomena or environmental condition(s), and secondly, transmitting the collected data to a remote central server for the processing and/or analysis of the data. In order to facilitate the latter task, each of the network nodes may be equipped with a relatively low-power radio transceiver with reduced range coverage. Cooperation between the radio transceivers corresponding with the network nodes is used to form a wireless ad hoc network for routing data sensed by one of the network nodes, generally referred to as the source node, to the remote central server, generally referred to as a destination node, through selected network nodes between the source node and the destination node via multi-hop transmission, such selected network nodes being hereinafter referred to as forwarding nodes.
A problem of wireless sensor networks, particularly when the network nodes are implemented by way of electronic devices powered by battery, is that loss of battery in one or more of the network nodes may cause data loss and, in the worst case, a complete failure, in the operation of the wireless sensor network.
In order to address the issue of battery conservation in the network nodes, it has been previously-proposed to cyclically operate a wireless sensor network in one of two modes of operation: a sleep mode and an active mode. In the sleep mode of operation, the radio transceivers of the network nodes are switched off and so, in this mode of operation, the network nodes do not contribute in the forwarding of data. In the active mode of operation, neighbouring network nodes, and specifically radio transceivers corresponding thereto, communicate with each other and are involved in the forwarding of data in the direction of and, ultimately, to the destination node. In order to facilitate such communication, in the active mode, those network nodes that are involved in forwarding the data towards the destination node are synchronised such that the scheduling of data receipt and/or transmission between them is conducted in such a way that a scenario of data loss is reduced or altogether avoided. In this regard, IEEE Standard, "Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks", IEEE, Los Alamos, 2003, describes a synchronisation strategy for use in a wireless network that is implemented by periodically transmitting beacons from a central network coordinator to the network nodes. After beacon reception, the radio transceiver of a synchronised network node listens to the radio channel established between the radio transceivers of the network nodes for a time-period of such a duration that data packets may be received from neighbouring network nodes and, if needed, transmitted onwards towards the destination node. After completion of these tasks, and until the next beacon is received, the aforementioned synchronised network node is operated in the sleep mode, with its associated radio transceiver being powered off. The performance gain obtained with this power management strategy is governed by the duty cycle of the network node, which is defined as the ratio of the length of the active period to one beacon interval. Other similar strategies have been described in J. H. Kim et. al., "Power saving method for wireless sensor network", U.S. Pat. No. 7,447,256, November 2008, and C. J. Yoon, "Energy-efficient medium access control protocol and system for sensor networks", US Patent Application 2006/0128349, June 2006.
In previously-proposed wireless sensor networks, static routing protocols have been used to propagate data packets from the source node to the destination node. Examples of such static routing protocols have been described by C. Perkins and E. Royer, in the document titled, "Ad-hoc on demand distance vector (AodV) routing" published in IEEE WMSCA, New Orleans, La., US, February 1999 and by D. Johnson, D. Maltz and J. Broch, in the document titled, "DSR: The dynamic source routing protocol for multi-hop wireless and ad-hoc networks", published in Ad-Hoc Networking, Addison Wesley, 2001. Such static routing protocols rely on the establishment of a single path from the source node to the destination node before the transmission of data by the source node to those network nodes determined in accordance with the static routing protocol for forwarding data to the destination node. Due to the execution of route discovery and route maintenance procedures being done before transmission of the data from the source node, some drawbacks associated with static routing protocols include an increased protocol overhead and performance degradation in terms of energy consumption. Furthermore, since the protocol overhead generally exponentially increases with the number of network nodes, static routing protocols may not provide an energy-efficient solution for relatively large-scale wireless sensor networks.
For large-scale wireless sensor networks, it has been proposed to use a geographic routing protocol. An example of a geographic routing protocol has been provided by M. Zorzi and R. R. Rao in the document titled, "Geographic random forwarding (GeRaF) for ad-hoc sensor networks: multi-hop performance", published in IEEE Transactions on Mobile Computing, pp. 337-348, 2003. Geographic routing is based on the principle that a route for forwarding data from the source node to the destination node is dynamically constructed whilst data is being transmitted from the source node in the direction of, and to, the destination node via forwarding nodes. The aforementioned dynamic construction of the route is performed on the basis of information on the geographic location information of the involved forwarding nodes. In geographic routing, a node that has a data packet to transmit broadcasts a request message containing information on the geographical coordinates of the destination node. Network nodes within the radio coverage range of the broadcasting node each receive the request message, such network nodes being generally referred to as neighbouring network nodes. They then exploit their topological knowledge to calculate the advancement that they can offer towards the destination node and contend amongst each other to elect the next network node that is closest to the destination node. Since information is only locally exchanged between a node that has data to transmit and neighbouring network nodes, geographic routing scales with the size of the wireless sensor network in which it is implemented, thereby making it advantageous for use in large-scale wireless sensor networks compared to previously-proposed routing protocols, such as, for example, static routing protocols. A prerequisite for the application of geographic routing is that all network nodes know their own geographic location within the network. This geographic information may be: set manually at initial deployment of the network nodes; or be provided using a location positioning system such as a global positioning system (GPS) in an outdoor environment, or by using the positioning system proposed by S. Furrer, W. Schott and B. Weiss in U.S. Pat. No. 7,761,233, July 2010, for example.
Whilst geographic routing protocols alleviate some of the drawbacks associated with previously-proposed techniques/protocols, it is still a challenge to route data in a wireless sensor network, particularly one that is large-scaled, with improved reliability and network performance whilst also addressing energy consumption issues.

Method for routing data in a wireless sensor network


The present invention relates to a system and methods for rendering simulated three-dimensional images on a display device. More particularly, the present invention involves systems and methods for organizing, configuring and transmitting data from a server to a client for the display of a simulated three-dimensional image.

Background: The use of computers and computing devices is constantly increasing within our society. Personal computer use, as well as business computing use, is on the rise. Furthermore, many smaller devices, such as cell phones, personal digital assistants, and pagers, are being developed to display additional information to a user. As advances in computing devices occur, advances in display devices for displaying information on the computing devices are also occurring.
Advances in display technology for graphics and object images are also occurring. Robust display systems and programs for displaying pixel-based images are replacing simple text and character based graphical imaging systems. Many of the display systems and programs allow for the display of higher definition images and incorporate functions for manipulating such displays. The use of objects and displayed images to display information is becoming more popular in the marketplace. Advancements in imaging and object displays are very apparent on the Internet. As the Internet has evolved, graphical displays and graphical interaction over the Internet has become more popular. Many web pages contain multiple images and/or pictures for display on a display screen of a computing device.
As more pictures and/or three-dimensional objects are incorporated with Internet pages, more time and energy is required to create these complex resources and more memory and computer CPU power is required to load them. Furthermore, the amount of bandwidth required to transmit such object representation data between computing devices is also increased, thereby making transmission of and interaction with rich multimedia and object representation data practical. Most existing methods and technologies display three-dimensional objects using interactive three-dimensional display programs called geometry rendering engines which transform three-dimensional data and detail imagery into pixels in a process called rendering. Each polygon or piece of the geometry may have many detail images. These methods don't require large bandwidth, but are very computationally intensive requiring fast CPU's, extra memory and a period of time between each interaction to transform the geometry and its images to render and display it. In addition, the meshwork of geometry required by geometry rendering engines requires significant work to capture, optimize and combined with detail images to represent a three-dimensional object. This is especially true of complex shapes which are cost-prohibitive to create. A vehicle would be a good example of an intricate and complex three-dimensional shape.
Another type of interactive three-dimensional display program uses a matrix of captured images to simulate the object by displaying pictures of it at different angles as the user interacts with it using an input device. This technology is very cost effective for production but requires more bandwidth and a fraction of the computation to display. There aren't any products on the market that have utilized this methodology to configure an object or provide auxiliary information about individual views of the object.
Object representation data sets require specific interactive three-dimensional display programs specific to the format of their data for interpretation, manipulation and display. These programs must typically be stored on the computing device and linked to the type of object representation data they can interpret. For instance, a web-browser surfing the Internet may attempt to display object representation data loaded from a web page. If the interactive display program that can interpret, display and interact with the object representation data hasn't been installed and associated with the web-browser or is not recognized by the web-browser, the web-browser may not be able to interpret, display or interact with it. In many cases, the web-browser may be altered to represent the object data by loading the interactive display program as a web-browser plug-in, or supplemental program, specifically designed to represent it in the web-browser. The use of plug-ins with web-browsers is well known.
Although plug-ins are typically available for displaying images, their use can be complicated and frustrating. Typically, a user first finds out that they are unable to view an object or animation at the time they try to download it. If it does not load and display, a user may or may not be provided with a link for obtaining a plug-in for viewing the desired object representation data, as seen with certain popular operating systems and media types, such as QuickTime VR™, which is installed with the incorrect display type by default in Microsoft Windows™. If a plug-in exists, a user is typically required to download the plug-in, install the plug-in, reboot their computing device, and reload the object representation data needing the plug-in. These steps take time and may be frustrating to the average computer user. Thus, many users just ignore the plug-ins and avoid viewing objects that their web-browser does not display by default.
Furthermore, current client applications operating on electronic devices such as personal digital assistants or cell phones are limited by the amount of available memory and computing power required by the interactive display programs and the object representation data they interpret and display.
Therefore, it is desirable to provide a system and methods for capturing, interpreting, displaying and interacting with objects, animations, and where applicable, information about the object, without the requirement of a plug-in to view the images. Furthermore, it is desirable to provide a system and method that easily and cost-effectively creates object representation data for a wide array of display devices that differ in computational power, memory and input methods.

Three-dimensional imaging system and methods


A method for producing a trans-esterified hydroxypropyl lignin (HPL) is provided in one example embodiment and includes precipitating a lignin, dissolving the precipitated lignin in a solution, adding a reagent to the solution, adjusting the pH of the solution, allowing reactions in the solution to occur for a predetermined amount of time, precipitating the solution to produce a precipitate, and washing, filtering, and drying the precipitate to produce the trans-esterified HPL. In one example, a thermoplastic may be added to produce a trans-esterified HPL/thermoplastic blend.

A plastic material is any of a wide range of synthetic, semi-synthetic, or natural organic solids that may be moldable. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. Early plastics were bio-derived materials such as egg and blood proteins, which are organic polymers. In the 1800s, the development of plastics accelerated with Charles Goodyear's discovery of vulcanization as a route to thermoset materials derived from natural rubber. After the First World War, improvements in chemical technology led to an explosion in new forms of plastics. Among the earliest examples in the wave of new polymers were polystyrene (PS) and polyvinyl chloride (PVC). The development of plastics has come from the use of natural plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely synthetic molecules (e.g., bakelite, epoxy, PVC). Plastics are durable and degrade slowly because the chemical bonds that make plastic so durable, make it equally resistant to natural processes of degradation. As a result, most plastic we use today will either be incinerated or end up in a landfill for many years.

This patent is subject to a terminal disclaimer.

Chemical modification of lignin and lignin derivatives


An apparatus for detecting the presence of a wafer cassette, or pod, resting on an arrangement of pins allows cassette detection without interfering with insertion of a robotic paddle arm beneath the cassette to remove it for transport. A cassette resides on an arrangement of beveled pins which mate with corresponding receptacles on the underside. Pins supporting the cassette have a spring biased, hollow outer cylinder coaxially mounted around a center post. A cassette placed on the pins displaces the outer cylinder downward a sufficient distance to trigger a sensor. Upon removal of the cassette, the outer cylinder is displaced upwards, resetting the sensor.

In a semiconductor wafer processing environment, semiconductor wafers must be protected from contaminants and physical agitation. Such wafers are used to manufacture electronic components such as computer memory and microprocessors, and require certain physical characteristics so that electronic circuit elements may be fabricated onto the wafer surface. Manufacturing imperfections, such as those which can arise from dust, dirt, bumping, and jarring, can render a wafer unusable.
Accordingly, such wafers are often stored and transported in a sealable container called a wafer pod, or cassette. Such cassettes have a series of interior ridges on opposing sides to support a batch of wafers horizontally, and a removable door to allow access to the contents. Typically an automated, apparatus, such as a robotic arm or conveyor system, is used to transport these cassettes to minimize human manipulation which can lead to dropping and bumping of a loaded cassette, and further to damage and loss of wafer stock. Such an apparatus transports cassettes between different processing stations during various phases of the wafer manufacturing and treatment process.
At each processing station, the cassette is placed on a support platform which includes an arrangement of pins having beveled tops called a nest, which mate with corresponding beveled receptacles on the bottom of the cassette. The beveled tops allow precise, consistent placement while affording some tolerance of movement when placing the cassette on the pins. A typical prior art pin assembly is shown in FIGS. 1a, 1b. Typically three pin assemblies are used to support a cassette, of which a single traditional pin assembly 10 is shown in FIG. 1a. The beveled edges 12 mate with a corresponding beveled surface 14 on a cassette 16 at a contact area 18, as shown in FIG. 1b.
Removal of the cassette from the nested position on the pin assemblies can involve insertion of a robotic arm, or paddle, under the cassette between the pin assemblies, and lifting upwards. Traditional pin arrangements, however, incorporate cassette sensing pads which reside under the cassette in the area between the pins to sense the presence of a cassette by being displaced downward. Such pads, therefore, interfere with insertion of the paddle underneath the cassette.
A typical cassette receptacle and pin assembly arrangement is shown in FIGS. 2a, 2b, respectively. Two triangular orientations are commonly used. On the bottom side of a cassette 56, a larger, outer pin assembly receptacle orientation 42 is used to support a cassette nested at a processing station, while an inner pin assembly receptacle orientation 44 is used by a robotic paddle arm to transport cassettes between processing stations. The corresponding pin assembly orientations on the processing station 48 are shown in FIG. 2b. The inner set of pins 54 is mounted on a paddle 46, while the outer set 52 corresponds to placement at the processing station 48. Referring to FIGS. 2a, 2b, paddle 46 can effect removal of cassette 56 by being inserted between the outer set of pins 52 beneath the cassette 56, and lifting upward such that inner pins 54 engage inner receptacles 44.
Prior art cassette detection methods using cassette sensing pads 58 are incompatible with the use of the paddle 46 in FIG. 2b. As such pads reside within the paddle exclusion zone 60, they can interfere with the insertion of the paddle 46 between the outer set of pins 52 beneath the cassette 56. Alternative sensor placement is undesirable due to the need to maintain compliance with industry standards, and alternate non-interfering insertion paths of the paddle can complicate design of new systems and may not be suitable for existing paddle systems.

Semiconductor wafer cassette positioning and detection mechanism