The purpose of the present invention is to provide a method for efficiently producing an olefin (co)polymer containing a constituent unit derived from 1-butene, the (co)polymer having a molecular weight that is sufficiently high even for high temperature conditions that are beneficial for industrial production methods. This purpose can be achieved by means of a method for producing an olefin (co)polymer containing a constituent unit derived from 1-butene, wherein at least 1-butene and, if necessary, an α-olefin having 2 or more carbon atoms (excluding 1-butene) and other monomers are (co)polymerized in the presence of an olefin polymerization catalyst that contains (A) a crosslinked metallocene compound represented by general formula [I] and (B) at least one type of compound selected from among (b-1) an organic aluminum oxy compound, (b-2) a compound that forms an ion pair upon a reaction with the crosslinked metallocene compound (A), and (b-3) an organic aluminum compound, at a polymerization temperature of 55-200° C. and a polymerization pressure of 0.1-5.0 MPaG.

In recent years, metallocene compounds have been known as homogeneous catalysts for olefin polymerization. With regard to methods for polymerizing olefins (in particular, methods for polymerizing α-olefins) by use of metallocene compounds, since isotactic polymerization has been reported by W. Kaminsky et al., a lot of improvement studies have been conducted for improvement of stereoregularity and polymerization activity (Non-Patent Document 1).
In α-olefin polymerization by use of metallocene compounds, it is known that the stereoregularity and molecular weights of resultant olefin polymers greatly vary by the introduction of substituents to the cyclopentadienyl ring ligands of the metallocene compounds or by the crosslinking two cyclopentadienyl rings.
For example, when metallocene compounds having a ligand in which a cyclopentadienyl ring and a fluorenyl ring are crosslinked with each other are used as a polymerization catalyst for propylene, in terms of the stereoregularity of polymers, use of dimethylmethylene(cyclopentadienyl) (fluorenyl)zirconium dichloride gives syndiotactic polypropylene (Non-Patent Document 2); use of dimethylmethylene(3-methylcyclopentadienyl) (fluorenyl)zirconium dichloride, which has a methyl group attached to the 3 position of a cyclopentadienyl ring, gives hemi-isotactic polypropylene (Patent Document 1); and use of dimethylmethylene(3-tert-butylcyclopentadienyl) (fluorenyl)zirconium dichloride, which has a tert-butyl group attached to the 3 position of a cyclopentadienyl ring, gives isotactic polypropylene (Patent Document 2). A metallocene compound is also being considered in which some of the hydrogen atoms of a cyclopentadienyl group that is a ligand portion of the metallocene compound are substituted with alkyl groups (Patent Document 3).
In modifying these metallocene compounds, it is possible to obtain relatively high melting points, an indicator of the stereoregularity of a polymer, and to obtain sufficiently high molecular weight. Also, it is possible to produce a polymer with a high melting point and a sufficiently high molecular weight.
As an example of producing a poly-1-butene using such a metallocene catalyst as described above, a polymerization example with an ethylene bis(indenyl)zirconium dichloride is described in Non-Patent Document 3, but there is a problem such that a poly-1-butene obtained by polymerization using such a catalyst has a low molecular weight and the catalyst has a low polymerization activity as well.
As a catalyst capable of producing a poly-1-butene having a high molecular weight, Patent Document 4 describes a catalyst for olefin polymerization that is composed of a metallocene compound and an aluminoxane, but there is a problem such that a resultant poly-1-butene has a low molecular weight and the catalyst has an insufficient polymerization activity.
As an example of producing a poly-1-butene using another metallocene compound, an olefin polymerization catalyst composed of a metallocene compound and an aluminoxane described in Patent Document 5 and an olefin polymerization catalyst composed of a metallocene compound and an aluminoxane described in Non-Patent Document 3 are reported, but there is a problem such that both of them have an insufficient polymerization activity.

Production method of olefin (co)polymer containing constituent unit derived from 1-butene


An integrated manifold system maximizes space for the circuit board while enabling efficient control of one or more pneumatic devices. The manifold system includes a manifold block, a solenoid valve attached to the manifold block, and a circuit board for controlling the solenoid and other components of an air suspension system. The manifold block includes at least one service port for connecting to a pneumatic device such as an air spring, and a supply port for connecting to a compressor. The solenoid valve is mounted to the manifold block with its longitudinal length being generally parallel to the service port. The circuit board is mounted adjacent to the solenoid valve and oriented generally parallel to the solenoid and service port. A cover encloses the solenoid valve and the circuit board. In one embodiment, the solenoid valve is in fluid communication with the supply port. The solenoid valve is uniquely associated with the service port.

The present invention relates to vehicle air suspension systems, and more particularly to an integrated manifold system for selectively controlling the components of an air suspension system.
Air suspension systems are well known for providing a softer, more comfortable ride for a vehicle. Other common applications for air suspension systems include: raising or lowering a vehicle; leveling a vehicle that is under a load; leveling recreational vehicles parked on inclined surfaces; and altering the performance characteristics of a vehicle. Air suspension systems may be installed on a vehicle by the original equipment manufacturer, or they may be purchased as aftermarket products that are substitutes or supplements for convention coil spring suspensions.
Common air suspension systems typically include one or more pneumatic devices, such as air springs, connected between the vehicle axles and the vehicle chassis. Pressurized air from a compressor or alternate source can be forced into or exhausted from one or more of the air springs to provide the vehicle with desired suspension characteristics.
As air suspension systems become more complex, manufacturers have utilized integrated manifold systems to control the air flow between the compressor and the air springs. For example, pressurized air from a compressor is routed to a single input port on a manifold block, and then routed out of the manifold block through a plurality of output ports, with each output port connected to one of the air springs. One or more valves on the manifold can be controlled to select which output ports are connected to the pressurized air source, and which output ports are connected to an exhaust port for selectively filling and exhausting the air springs. The valves may be solenoid valves that are electrically controlled by a controller connected to the system.
One such manifold system is shown in FIGS. 1 and 2 and generally designated 300. In this system, a plurality of manifold blocks 302, 304 and 306 are stacked on top of each other. The upper block 302 defines a plurality of ports for receiving solenoid valves 308 that extend into the upper block 302 in a direction generally perpendicular to the upper face 310 of the block 302. The lower manifold blocks 304, 306 each include internal ports that communicate with the solenoids and with service ports positioned on the exterior of the blocks 304, 306. Outlet fittings 312 connected to the service ports may be connected to air springs with hoses attached to the fittings 312. One of the blocks includes an supply port (not shown) for receiving pressurized air from a compressor. In general, each of the solenoid valves 308 directly communicates with one of the service ports with a movable poppet attached to the plunger of the solenoid. The poppet may be moved between a first position in which the associated service port is sealed from the supply port and a second position in which air from the supply port is allowed to flow through the associated service port. Circuit boards 320, 321 are stacked over the upper ends of the solenoids and are electrically connected to the solenoids. The circuit boards 320, 321 communicate with a controller to selectively activate the solenoids. A cover 330 is attached over the solenoids and the circuit boards to form a sealed enclosure for the system. A similarly configured manifold unit with "vertically oriented" solenoid valves that are mounted perpendicular to the upper surface of a manifold block is manufactured and sold by Accuair™ and marketed to as the "VU4 Solenoid Valve Unit".
Manifold systems such as those described above suffer from a variety of difficulties. First, the perpendicular orientation of the solenoids with respect to the manifold blocks limits the area over which the circuit board can be mounted as the circuit board must be constrained to the size of the vertical ends of the solenoids to prevent it from extending beyond the edges of the manifold block. Additional solenoid valves can increase this surface area, but they also increase the need for more circuit board components. Second, the vertical orientation of the solenoids limits the usable space on the circuit board, because the area of the circuit board immediately above each solenoid must be free from components to allow enough space for the solenoid. The combination of (1) limited space on the manifold for mounting the circuit board and (2) limited usable space on the circuit board limits the amount of components that can be attached to the circuit board for operating and monitoring the suspension system, and often requires the use of multiple, stacked circuit boards. In addition, the vertical, direct acting solenoids require many ports to be formed into the manifold blocks, which can result in the need for multiple, stacked manifold blocks and can require tedious manufacturing work to form ports with the necessary depth. This can prevent the formation of manifold blocks by some of the most cost effective methods, such as injection molding. As a result of these and other difficulties, manufacturers continue to search for a more space efficient manifold system that can be cost effectively manufactured.

Integrated manifold system for controlling an air suspension


A drive device including a planetary gear reduction device having at least two stages and an output shaft, and a driven shaft to support a driven member rotatively driven by torque reduced by the planetary gear reduction device and transmit the torque from the output shaft to the driven member. Each stage of the planetary gear reduction device includes a sun gear, an outer gear, multiple planetary gears, a carrier, and a support shaft. The output shaft is provided to the carrier of the last stage. Central axes of the sun gear, the outer gear, the carrier, the output shaft, the driven shaft, and the driven member are all arranged coaxially with one another and at least one carrier is floatingly supported relative to the outer gear. The carrier is formed as a single integrated unit having holes into which both ends of the support shaft are fitted.

1. Field of the Invention
Exemplary aspects of the present invention generally relate to a drive device that rotatively drives a driven member via a planetary gear reduction device, and an image forming apparatus including the drive device.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, printers, facsimile machines, and multifunction devices having two or more of copying, printing, and facsimile functions, typically form a toner image on a recording medium (e.g., a sheet of paper, etc.) according to image data using an electrophotographic method. In such a method, for example, a charger charges a surface of a rotatable cylindrical image carrier (e.g., a photoconductor); an irradiating device emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor; a transfer device transfers the toner image formed on the photoconductor directly onto a sheet or primarily transfers the toner image from the photoconductor onto a rotatable seamless belt (e.g., an intermediate transfer belt) and then secondarily transfers the toner image from the belt onto a sheet; and a fixing device applies heat and pressure to the sheet bearing the toner image to fix the toner image onto the sheet. The sheet bearing the fixed toner image is then discharged from the image forming apparatus.
The image forming apparatuses often include a drive device that transmits torque from a drive source to the photoconductor or the intermediate transfer belt via a planetary gear reduction device to rotatively drive the photoconductor or the intermediate transfer belt. The planetary gear reduction device has good durability and provides a higher reduction rate with reduced installation space compared to large-sized resin gears and so forth.
Various types of drive devices using the planetary gear reduction device have been proposed. For example, JP-2008-151868-A discloses a drive device 800 that rotatively drives a driven member such as a drive roller 80 for the photoconductor or the intermediate transfer belt as illustrated in FIG. 1. Front and rear portions of the drive roller 80 are held by front and rear holders 81 and 82 via bearings, respectively, and the front and rear holders 81 and 82 are positioned by front and rear lateral plates 83 and 84, respectively. A planetary gear reduction device 85 and a motor 86, which is a drive source for the planetary gear reduction device 85, are disposed within the drive roller 80 and are held by the rear holder 82. An end of the motor 86 opposite an output end thereof is supported by the rear lateral plate 84 via a bearing. Such a configuration allows installation of the drive system within the drive roller 80, thereby reducing installation space of the drive device 800 as a whole and thus providing a more compact image forming apparatus.
In another approach, JP-H10-240069-A discloses a drive device in which a planetary roller reduction mechanism and a motor are provided outside a photoconductor so that output shafts of each of the motor, the photoconductor, and the planetary roller reduction mechanism are arranged coaxially with the other. Accordingly, installation space of the drive device in a direction of diameter of the photoconductor can be reduced, thereby making the image forming apparatus more compact. In addition, in the planetary roller reduction mechanism used for the above-described drive device, only a single side of a support shaft of a planetary roller is supported by a roller support member, thereby reducing installation space of the planetary roller reduction mechanism in an axial direction of the mechanism.
In yet another approach, JP-2001-330087-A discloses a drive device (an actuator) including a planetary gear reduction device. A first sun gear in the first stage of the planetary gear reduction device is extended to an opening formed in an output shaft-side of a housing that holds an outer gear, and sun gears in the second stage and so on are rotatably mounted to the first sun gear. Planetary gears, support shafts of each of the planetary gears, and carriers are assembled in advance as a carrier assembly and then installed in the housing. Each of the support shafts is inserted into needle bearings provided to each of the planetary gears, and both ends of the support shaft, each having a reduced diameter, are sandwiched by first and second lateral plates of the carrier, respectively. The first lateral plate has multiple legs formed together with the first lateral plate as a single integrated component, and the first and second lateral plates are coupled to each other by the legs and the support shafts sandwiched by the first and second lateral plates. Such a configuration allows easy assembly of the planetary gear reduction device and prevents deformation of the carrier assembly, thereby improving durability of each gear.
However, in the drive device 800 disclosed in JP-2008-151868-A, both the motor 86 and the rear holder 82 are positioned by the rear lateral plate 84. The motor 86 is also held by the rear holder 82. In other words, the motor 86 is positioned by the two members, that is, the rear lateral plate 84 and the rear holder 82. Consequently, a variation in the size of each component may cause irregular assembly at a portion where the motor 86 is positioned by the rear lateral plate 84 or deformation of the motor 86 or the rear holder 82. As a result, the planetary gear reduction device 85 and the motor 86 cannot be accurately positioned relative to the driven member such as the photoconductor and the intermediate transfer belt, and the driven member cannot be accurately positioned relative to the rear lateral plate 84, thereby preventing accurate rotation of the driven member.
In the drive device disclosed in JP-H10-240069-A, because only the single side of the support shaft of the planetary roller is supported by the roller support member as described previously, the support shaft of the planetary roller may be tilted. Consequently, the planetary roller may partially contact a sun roller or a stationary roller, thereby degrading durability of the planetary roller and causing rotational fluctuation of the planetary roller. As a result, the drive device cannot accurately drive the driven member such as the photoconductor.
With regard to the drive device disclosed in JP-2001-330087-A, a variation in the size of each component and assembly tolerance may displace a first hole formed in the first lateral plate to hold one end of the support shaft of each of the planetary gears and a second hole formed in the second lateral plate to hold the other end of the support shaft from each other, thereby possibly tilting the planetary gears. The tilt of the planetary gears degrades durability of the planetary gears and causes rotational fluctuation of the planetary gears. As a result, the drive device cannot accurately drive the driven member. In addition, alignment clearance is not provided between each of the carriers and each of the sun gears respectively fitted into input shafts. Consequently, rotational fluctuation caused by tolerances of each of the planetary gears, the sun gears, and the stationary gear is transmitted to the output shaft, thereby preventing accurate driving of the driven member.
Inaccurate driving of the driven member causes speed fluctuation of the driven member such as the photoconductor and the intermediate transfer belt, resulting in jitter or uneven image density in an output image. Continuous speed fluctuation of the photoconductor or the intermediate transfer belt at a certain frequency periodically causes uneven image density throughout the output image, resulting in stripes, or banding. In addition, speed fluctuation of the photoconductor shifts a sub-scanning position of an exposure line and a sub-scanning position upon primary transfer of the toner image from the photoconductor onto the intermediate transfer belt. Further, speed fluctuation of the intermediate transfer belt shifts a sub-scanning position upon secondary transfer of the toner image from the intermediate transfer belt onto the sheet as well as upon primary transfer of the toner image. Thus, banding caused by speed fluctuation of the photoconductor and the intermediate transfer belt considerably degrades image quality.

Drive device and image forming apparatus including same


A period from ignition timing to maximum heat release rate timing, at which a heat release rate is maximum, within a combustion period of air-fuel mixture is defined as a first combustion period that is one of characteristic values of a heat release rate waveform. The first combustion period is estimated based on a cylinder volume at the maximum heat release rate timing (maximum heat release rate cylinder volume) irrespective of any of an engine load factor, an EGR rate, an air-fuel ratio, an oil or coolant temperature and opening and closing timing of an exhaust valve through correction by the use of the exponential function of an engine rotation speed with an exponent of a value commensurate with a tumble ratio. The heat release rate waveform is calculated by using the estimated first combustion period.

1. Technical Field
The disclosure relates to a heat release rate waveform calculation apparatus and heat release rate waveform calculation method for calculating a heat release rate waveform in a spark-ignition internal combustion engine and, more particularly, to a technique for obtaining a heat release rate waveform by focusing on a period from ignition of air-fuel mixture to timing at which a heat release rate is maximum (in this specification, this period is referred to as first combustion period).
2. Description of Related Art
Generally, in order to express a combustion state of an internal combustion engine, a heat release rate in a cylinder is approximated by the use of a Wiebe function. The Wiebe function is able to suitably express a heat release rate waveform by specifying a plurality of parameters, and is utilized to estimate a heat release rate, a mass fraction burned, or the like, in combustion of an internal combustion engine.
For example, in a method of determining the parameters of the Wiebe function, described in Japanese Patent Application Publication No. 2007-177654 (JP 2007-177654 A), a shape parameter m of the Wiebe function is identified by the use of a predetermined expression on the basis of a fraction burned at a crank angle at which a heat release rate is maximum. The other parameters, that is, k, a/θpm+1 and θb, are also respectively identified by the use of predetermined expressions, and then the Wiebe function is determined so as to be adapted to an actual heat release pattern with high accuracy.
JP 2007-177654 A describes as follows. The plurality of parameters m, k, a/θpm+1, θb are identified in that way, and then work for determining the Wiebe function is performed for each of various operating conditions. Thus, the relationship between these parameters and operating parameters (load factor, rotation speed, air-fuel ratio, spark timing, and the like) of an internal combustion engine is acquired. JP 2007-177654 A further describes that, when the thus acquired relationship is utilized, it is possible to determine the Wiebe function for any operating condition of the internal combustion engine and express the combustion state of the internal combustion engine with high accuracy.
However, JP 2007-177654 A does not specifically describe a method of determining the relationship between the parameters m, k, a/θpm+1, θb of the Wiebe function and the operating parameters of the internal combustion engine. Therefore, actually, the parameters m, k, a/θpm+1, θb need to be identified for each of almost all the operating conditions, and then the Wiebe function needs to be determined for each of the operating conditions. That is, there is room for further reducing man-hours for generating heat release rate waveforms and reducing cost in the existing method.
With the above-described method, the entire heat release rate waveform is not expressed until parameters m, k, a/θpm+1, θb are identified and then the Wiebe function is determined, and, after that, the combustion state is allowed to be evaluated on the basis of the expressed entire heat release rate waveform. Thus, it is not possible to estimate and evaluate only, for example, a first combustion period (a period from ignition of air-fuel mixture to timing at which the heat release rate is maximum) with a simple method without expressing the entire heat release rate waveform.

Heat release rate waveform calculation apparatus and heat release rate waveform calculation method for internal combustion engine


An apparatus for axially displacing a downhole tool or a tubular in a well bore equipped with a wellhead is described. The apparatus includes a lifting mechanism such as an hydraulic cylinder or a mechanical jack that is connected to a lift rod string. The lift rod string includes a latch for engaging the tubular or the downhole tool. The apparatus further preferably includes a motor for rotating the lift rod string to permit rotationally releasable downhole equipment to be released by rotational movement of the lift rod string. The apparatus is also useful for removing obstructions in a casing of the well bore, and for removing soluble solids from a tubular in the well bore. The advantage is a simple, light weight, lifting apparatus that is versatile, yet inexpensively manufactured and readily transported from one wellhead to another.

Downhole operations and the handling of downhole well tools in completed wells has always presented a certain challenge, especially when working in wells having a natural pressure that exceeds atmospheric pressure, necessitating the containment of the well at all times. A further challenge has been the maintenance of well bores which pass through production zones that are not well suited to continuous production. For example, a production zone which yields both water and oil or gas or any combination thereof may require relatively frequent repositioning of a lower end of a production tubing in order to recover oil or gas efficiently. Production zones which produce crude oil high in waxy compounds or asphaltines, or laden with salts, which tend to plug casing perforations and therefore require frequent treatment to maintain an economic flow of hydrocarbon are further examples of such production zones.
To date, the maintenance of such wells has proven time-consuming and expensive. For example, in wells which produce both oil, water and gas and/or water and gas and have a mobile water/hydrocarbon interface, the production of hydrocarbon gradually decreases over time until only water or gas is produced from the well. Relocation of the bottom end of the production tubing string is then required to recommence oil production. The relocation of the tubing string has been a complex process which involved many time-consuming and expensive steps that are well known in the art. It is not difficult to appreciate that there is a need for a more efficient and less costly system for producing oil or gas from such wells. Such a system is described in applicant's copending patent application incorporated herein by reference. The apparatus described in that patent application eliminates many of the shortcomings of prior art procedures for selectively producing fluids from wells, performing barefoot completions of well bores in sensitive zones, and other downhole operations using production tubing and tools that require axial displacement within a limited range in a well bore. At the time of filing that patent application, it was considered that the apparatus described in U.S. Pat. No. 4,867,243 which issued on Sep. 19, 1989 to Garner et al. would be suitable for effecting the axial displacement of the downhole well tools. It has now been recognized that such prior art tools for inserting mandrels through wellheads is not necessarily adequate or optimal for performing the axial displacement of such downhole well tools.
There are several reasons why such prior art tools are not optimal tools for this purpose. First, they are designed for inserting wellhead isolation mandrels into wellheads and withdrawing them from the wellheads after the well is serviced. Since wellhead isolation mandrels are of inconsequential weight, they are stroked through a wellhead relatively easily. Moving a tubing string of 4,500' (1,500 meters), which is not uncommonly encountered in handling downhole well tools, may require a force in excess of 50 tons. The force required is due not only to the considerable weight to be lifted but also to the extra force required to unseat anchors and/or packers supporting the tubing string. Such forces may subject the wellhead to potentially damaging stresses. Second, wellhead isolation tools provide no mechanism for rotating a downhole tubing string since rotation is not required for the insertion or withdrawal of a wellhead isolation mandrel. When manipulating a downhole tubing string, however, rotational movement is often required in order to release or set components such as packers, anchors, hangers and the like. Considerable rotational force may be required to accomplish the release of such components and it is therefore desirable to provide a mechanism for selectively rotating the downhole string as required.
It has also now been recognized that certain downhole operations can be more economically performed through the wellhead with pressure containment than performing those operations using a rig, for example. It is also known that certain near-surface operations such as the drilling out of permanent bridge plugs, cement plugs or any other obstruction in the casing column during re-entries require pressure containment in order to avoid the escape of hydrocarbons to atmosphere and potentially dangerous releases of contained pressure. There therefore exists a need for an apparatus which is adapted to provide pressure containment while enabling downhole manipulations to move production tubing, and remove near-surface obstructions with or without the use of a telescoping joint in a tubing string.

Apparatus and method for axially displacing a downhole tool or a tubing string in a well bore


An object of the present invention is to provide a semiconductor device capable of radiating electron-beams only to a desired region without forming a layer for restricting the radiating rays. A source electrode 22 made of aluminum prevents the generation of bremsstrahlung even when the electron-beams are radiated to the source electrode in a exposed condition. Also, the source electrode having an opening 25 at above of a crystal defect region 11 is used as a mask when the electron-beams are radiated thereto. That is the source electrode made of aluminum can be used both as a wiring and a mask for the radiating rays.

An insulated gate bipolar transistor (hereinafter referred to as IGBT) 80 shown in FIG. 9 is known as a semiconductor device having a planar type high voltage-proof vertical element. The IGBT 80 is a semiconductor device which has both a high input impedance characteristic observed in a metal oxide field effect transistor (hereinafter referred to as MOSFET) and a low saturation voltage characteristic known as a characteristic of a bipolar transistor.
A substrate 82 used for the IGBT 80 includes a drain layer 3 with P+ type, an n+ type layer 5 and an n− type layer 7. Base regions 21 are formed in the n− type layer 7, and source regions 23 with n+ type are formed within the base regions 21. The surface of the n− type semiconductor layer 82 is covered with a gate oxidation layer 22.
Incidentally, a loss caused by switching arises as a result of a parasitic diode generated on a plane of a PN (positive-negative) junction 59. Japanese Patent laid-open publication No. Hei 7-135214 discloses a technology for selectively radiating electron-beams using a mask 41 shown in FIG. 9 during the manufacturing processes in order to avoid the generation of the parasitic diode. The beams pass through through-holes 43 formed in the mask 41 and irradiate on the IGBT 80. In this way, the life-time of carriers located on the plane of the PN junction 59 where the parasitic diode being generated can be shortened as a result of forming crystal defects 61.
In the manufacturing processes described above, unexpected variation of the threshold voltage in the IGBT 80 is possible because of generation of bremsstrahlung caused by the material of the mask 41 made generally of a heavy metal such as lead and the like.
Japanese Patent laid-open publication No. Hei 8-227895 discloses another IGBT 90 having layers for restricting electron-beams. As shown in FIG. 10, a layer 69 made of silicon nitride for restricting the beams is formed under a source electrode. Generation of bremsstrahlung is restricted even when the beams are radiated to the IGBT 90 due to masking by the restriction layer 69.
However, the number of processes is increased because the processes for forming the restriction layers 69 made of silicon nitride is required in the conventional method.

Semiconductor device with metal wire layer masking


A first seal member is provided integrally on a surface of a first metal separator. The first seal member includes a base portion provided integrally on the first metal separator, a columnar portion protruding from the base portion, and a curved edge portion provided on the columnar portion. The curved edge portion has a predetermined radius of curvature.

1. Field of the Invention
The present invention relates to a fuel cell including an electrolyte electrode assembly, and metal separators for sandwiching the electrolyte electrode assembly. The electrolyte electrode assembly includes a pair of electrodes and an electrolyte interposed between the electrodes. In the fuel cell, fluid flow fields are formed on surfaces of the separators for supplying fluids such as a reactant gas and a coolant along surfaces of the separators. Each of the fluid flow fields is connected between a fluid supply passage and a fluid discharge passage.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell employs a membrane electrode assembly (MEA) which includes two electrodes (anode and cathode), and an electrolyte membrane interposed between the electrodes. The electrolyte membrane is a polymer ion exchange membrane. The membrane electrode assembly is interposed between separators. The membrane electrode assembly and the separators make up a unit of a fuel cell (unit cell) for generating electricity. A predetermined number of the fuel cells are stacked together to form a fuel cell stack.
In the fuel cell, a fuel gas (reactant gas) such as a gas chiefly containing hydrogen (hydrogen-containing gas) is supplied to the anode. The catalyst of the anode induces a chemical reaction of the fuel gas to split the hydrogen molecule into hydrogen ions (protons) and electrons. The hydrogen ions move toward the cathode through the electrolyte, and the electrons flow through an external circuit to the cathode, creating a DC electric current. A gas chiefly containing oxygen (oxygen-containing gas) or air is supplied to the cathode. At the cathode, the hydrogen ions from the anode combine with the electrons and oxygen to produce water.
In the fuel cell, the fuel gas, the oxygen-containing gas, and the coolant flow through their dedicated fluid passages which are hermetically sealed for preventing gas or liquid leakages. Typically, seal members are interposed between the electrolyte electrode assembly and the separator for preventing leakages. Various types of seal members are known, for example, Japanese Laid-Open Patent Application No. 2001-332276 discloses a seal member shown in FIG. 9. The seal member includes an elastic base gasket 1 with a higher hardness of 70 to 90 degree and gaskets 2 with a lower hardness of 30 to 50 degree. The base gasket 1 is made of a synthetic rubber or a synthetic resin, and the gasket 2 is made of a synthetic rubber. The gaskets 2 are placed on both surfaces of the base gasket 1.
In the seal member of Japanese Laid-Open Patent Application No. 2001-332276, the gaskets 2 may be displaced undesirably on the base gasket 1. If the desired sealing function of the gaskets 2 can not be performed due to the positional displacement, leakage of the reactant gas (fuel gas and/or oxygen-containing gas) and coolant may occur.
In an attempt to address the problem, U.S. Patent Application Publication No. US2002/0122970A1 discloses a method for fabricating a seal-integrated separator. According to the disclosure, a separator body of a fuel cell and seal members on both surfaces of the separator body are formed integrally into one piece. In contrast to the technique in which seal members are separately provided on both surfaces of the separator body, or the technique in which the separator body is coated with seal members, in the seal-integrated separator of U.S. Patent Application Publication No. US2002/0122970A1, the seal members are positioned with a high degree of accuracy, and the number of steps for assembling the fuel cells is significantly reduced.
Typically, the seal members are formed in a lip shape. The seal members are tapered to have thin end portions. Therefore, even if the seal members and the separator body are formed into one piece, the desired sealing performance may not be achieved for the fuel cell in some automobile applications.
Specifically, positional displacement may occur at the end portions of the seal members due to vibrations during the travel of the vehicle and impacts at the time of sudden acceleration and sudden braking. The positional displacement reduces the contact area of the seal members. If the positional displacement occurs, it is difficult to maintain the desired sealing performance. In the case of the fuel cell using a metal separator, surfaces of the metal separator are deformed, distorted or warped easily. However, the end portions of the seal members can not be deformed in accordance with the deformation of the metal separator. Thus, the sealing pressure between the surfaces of the separator and the seal member is not maintained at a sufficient level for sealing.
If a plurality of fuel cells are stacked together to form a fuel cell stack, the positional displacement occurs easily at the end portions of the seal members. Consequently, the end portions of the seal members are tilted, the surface pressure applied to the seal members is reduced, and the contact area between the separator and the seal members is reduced. It is difficult to maintain the desired sealing performance.

Fuel cell with a seal member integrally formed on a metal separator


This disclosure describes a system (100, 130) for a USB to Bluetooth audio bridging method and apparatus. The system includes a host device (102) having a first universal serial bus (USB) interface (107) and a second USB interface (110); an adaptor (108) in connection with the first USB interface (107) which is compatible to operate based on a Bluetooth-type communication protocol; a peripheral device (106) coupled to the second USB interface (110); and a mobile communication device (104) linked to the host device (102) via the adaptor (108). The mobile communication device (104) communicates an audio data signal to the adaptor (108) and an audio bridging device (116). The audio bridging device (116) maps the second USB interface (110) to the adaptor (108) and routes audio data signals alone or in combination with another audio data signals to the peripheral device (106) via the second USB interface (110).

Audio conferencing solutions facilitate communication between more than two users located at remote locations using an audio conferencing endpoint (AC endpoint) such as a speakerphone. At each location, the AC endpoint may be connected to terminal equipment (e.g., a mobile phone, a landline handset, a speaker, a microphone, etc.) via any of the physical interfaces, for example, a Universal Serial Bus (USB), a Small Computer System Interface (SCSI), an IEEE 1394 bus, optical fiber, etc. to provide or extend conferencing capabilities.
In order to wirelessly connect with the terminal equipment, state-of-the-art AC endpoints are made compatible with various wireless communication technologies, for example, IEEE 802.11b (Wi-Fi), IEEE 802.11a, Bluetooth, HomeRF, ZigBee, etc. implemented on the terminal equipment. This increases the manufacturing as well as maintenance cost of the AC endpoint due to a continual requirement for hardware and/or software upgrade to remain compatible with the wireless communication technology implemented on the terminal equipment.
Therefore, there exists a need for an alternative system that enables local connection between the terminal equipment and the AC endpoint while the AC endpoint being independent of the wireless communication technology implemented on the terminal equipment.

Universal Serial Bus-to-Bluetooth audio bridging devices


An ion-beam film deposition process is described for fabricating binary photomask blanks for selected lithographic wavelengths  less than 400 nm, the said film essentially consisting of the MOxCyNz compound where M is selected from chromium, molybdenum, tungsten, or tantalum or combination thereof in a single layer or a multiple layer configuration.

This invention relates to manufacture of binary photomask blanks in photolithography, using the ion-beam deposition technique. These masks can be used with short wavelength (i.e.,  less than 400 nanometer) light. Additionally, this invention relates to binary photomask blanks with single or multi-layered coating of chromium, molybdenum, tungsten, or tantalum metal and/or its compounds or combinations thereof, on the blanks.
Microlithography is the process of transferring microscopic circuit patterns or images, usually through a photomask, on to a silicon wafer. In the production of integrated circuits for computer microprocessors and memory devices, the image of an electronic circuit is projected, usually with an electromagnetic wave source, through a mask or stencil on to a photosensitive layer or resist applied to the silicon wafer. Generally, the mask is a layer of xe2x80x9cchromexe2x80x9d patterned with these circuit features on a transparent quartz substrate. Often referred to as a xe2x80x9cbinaryxe2x80x9d mask, a xe2x80x9cchromexe2x80x9d mask transmits imaging radiation through the pattern where xe2x80x9cchromexe2x80x9d has been removed. The radiation is blocked in regions where the xe2x80x9cchromexe2x80x9d layer is present.
The electronics industry seeks to extend optical lithography for manufacture of high-density integrated circuits to critical dimensions of less than 100 nanometer (nm). However, as the feature size decreases, resolution for imaging the minimum feature size on the wafer with a particular wavelength of light is limited by the diffraction of light. Therefore, shorter wavelength light, i.e. less than 400 nm are required for imaging finer features. Wavelengths targeted for succeeding optical lithography generations include 248 nm (KrF laser wavelength), 193 nm (ArF laser wavelength), and 157 nm (F2 laser wavelength) and lower.
Physical methods of thin film deposition are preferred for manufacture of photomask blanks. These methods, which are normally carried out in a vacuum chamber, include glow discharge sputter deposition, cylindrical magnetron sputtering, planar magnetron sputtering, and ion beam deposition. A detailed description of each method can be found in the reference xe2x80x9cThin Film Processes,xe2x80x9d Vossen and Kern, Editors, Academic Press NY, 1978). The method for fabricating thin film masks is almost universally planar magnetron sputtering.
The planar magnetron sputtering configuration consists of two parallel plate electrodes: one electrode holds the material to be deposited by sputtering and is called the cathode; while the second electrode or anode is where the substrate to be coated is placed. An electric potential, either RF or DC, applied between the negative cathode and positive anode in the presence of a gas (e.g., Ar) or mixture of gases (e.g., Ar+O2) creates a plasma discharge (positively ionized gas species and negatively charged electrons) from which ions migrate and are accelerated to the cathode, where they sputter or deposit the target material on to the substrate. The presence of a magnetic field in the vicinity of the cathode (magnetron sputtering) intensifies the plasma density and consequently the rate of sputter deposition.
If the sputtering target is a metal such as chromium (Cr), sputtering with an inert gas such as Ar will produce metallic films of Cr on the substrate. When the discharge contains reactive gases, such as O2, N2, CO2, or CH3, they combine with the target or at the growing film surface to form a thin film of oxide, nitride, carbide, or combination thereof, on the substrate. Usually the chemical composition of a binary mask is complex and often, the chemistry is graded or layered through the film thickness. A xe2x80x9cchromexe2x80x9d binary mask is usually comprised of a chrome oxy-carbo-nitride (CrOxCyNz) composition that is oxide-rich at the film""s top surface and more nitride-rich within the depth of the film. The oxide-rich top surface imparts anti-reflection character, and chemically grading the film provides attractive anisotropic wet etch properties, while the nitride-rich composition contributes high optical absorption.
In ion-beam deposition (IBD), the plasma discharge is contained in a separate chamber (ion xe2x80x9cgunxe2x80x9d or source) and ions are extracted and accelerated by an electric potential impressed on a series of grids at the xe2x80x9cexit portxe2x80x9d of the gun (ion extraction schemes that are gridless, are also possible). The IBD process provides a cleaner process (fewer added particles) at the growing film surface, as compared to planar magnetron sputtering because the plasma, that traps and transports charged particles to the substrate, is not in the proximity of the growing film as in sputtering. Moreover, the need to make blanks with fewer defects is imperative for next generation lithographies where critical circuit features will shrink below 0.1 micron. Additionally, the IBD process operates at a total gas pressure at least ten times lower than traditional magnetron sputtering processes (a typical pressure for IBD is xcx9c10xe2x88x924 Torr.). This results in reduced levels of chemical contamination. For example, a nitride film with minimum or no oxide content can be deposited by this process. Furthermore, the IBD process has the ability to independently control the deposition flux and the reactive gas ion flux (current) and energy, which are coupled and not independently controllable in planar magnetron sputtering. The capability to grow oxides or nitrides or other chemical compounds with a separate ion gun that bombards the growing film with a low energy, but high flux of oxygen or nitrogen ions is unique to the IBD process and offers precise control of film chemistry and other film properties over a broad process range. Additionally, in a dual ion beam deposition the angles between the target, the substrate, and the ion guns can be adjusted to optimize for film uniformity and film stress, whereas the geometry in magnetron sputtering is constrained to a parallel plate electrode system.
While magnetron sputtering is extensively used in the electronics industry for reproducibly depositing different types of coatings, process control in sputtering plasmas is inaccurate because the direction, energy, and flux of the ions incident on the growing film cannot be regulated (ref: The Material Science of Thin Films, Milton Ohring, Academic Press 1992, p. 137). In dual ion beam deposition proposed here as a novel alternative for fabricating masks with simple or complex, single-layered or multi-layered chemistries, independent control of these deposition parameters is possible.
This invention concerns an ion-beam deposition process for preparing a binary photo mask blank for lithographic wavelengths less than 400 nanometer, the process comprising depositing at least one layer of a MOxCyNz compound, where M is selected from the group consisting of chromium, molybdenum, tungsten, or tantalum or a combination thereof, on a substrate by ion beam deposition of chromium, molybdenum, tungsten, or tantalum and/or a compound thereof by ions from a group of gases;
wherein:
x ranges from about 0.00 to about 3.00;
y ranges from about 0.00 to about 1.00;
and z ranges from about 0.00 to about 2.00.
More specifically, this invention concerns a dual ion-beam deposition process for preparing a binary photo mask blank for lithographic wavelengths less than 400 nanometer, the process comprising depositing at least one layer of a MOxCyNz compound, where M is selected from chromium, molybdenum, tungsten, or tantalum or combination thereof, on a substrate;
(a) by ion beam deposition of chromium, molybdenum, tungsten, or tantalum and/or a compound thereof by ions from a group of gases, and
(b) by bombarding the said substrate by a secondary ion beam from an assist source of a group of gases wherein the layer or the layers are formed by a chemical combination of the bombarding gas ions from the assist source gas with the material deposited from the target or targets onto the substrate;
wherein:
x ranges from about 0.00 to about 3.00;
y ranges from about 0.00 to about 1.00;
and z ranges from about 0.00 to about 2.00.
Certain terms used herein are defined below.
In this invention, it is to be understood that the term xe2x80x9cphotomaskxe2x80x9d or the term xe2x80x9cphotomask blankxe2x80x9d is used herein in the broadest sense to include both patterned and UN-patterned photomask blanks. The term xe2x80x9cmultilayersxe2x80x9d is used to refer to photomask blanks comprised of layers of films deposited with distinct boundaries between the two layers or a distinct change in at least one optical property between two regions. The layers can be ultra-thin (1-2 monolayers) or much thicker. The layering controls optical and etch properties of the photomask blank.
Optical density of the binary blank is defined as the logarithm of the base of 10 of the ratio of the intensity of the incident light to the intensity of the transmitted light.
Single Ion Beam Deposition Process
A typical configuration for a single ion beam deposition process is shown in FIG. 2. It is understood that this system is in a chamber with atmospheric gases evacuated by vacuum pumps. In the single IBD process, an energized beam of ions (usually neutralized by an electron source) is directed from a deposition gun (1) to a target material (2) supported by target holder (3) which is sputtered when the bombarding ions have energy above a sputtering threshold energy for that specific material, typically xcx9c50 eV. The ions from the deposition-gun (1) are usually from an inert gas source such as He, Ne, Ar, Kr, Xe, although reactive gases such as O2, N2, CO2, F2, CH3, or combinations thereof, can also be used. When these ions are from an inert gas source the target material is sputtered and then deposits as a film on the substrate (4), shown with substrate holder (5). When these ions are from a reactive gas source they can combine with target material (2) and the product of this chemical combination is what is sputtered and deposited as a film on the substrate (4).
Commonly, the bombarding ions should have energies of several hundred eVxe2x80x94a range of 200 eV to 10 KeV being preferred. The ion flux or current should be sufficiently high ( greater than 1013 ions/cm2/s) to maintain practical deposition rates ( greater than 0.1 nm/min). Typically, the process pressure is about 10xe2x88x924 Torr, with a preferred range 10xe2x88x923-10xe2x88x925 Torr. The target material can be elemental, such as Cr,, Mo, Ta, W, or it can be multi-component such as MoxCry, or it can be a compound such as CrN. The substrate can be positioned at a distance and orientation to the target that optimize film properties such as thickness uniformity, minimum stress, etc.
The process window or latitude for achieving one film property, for example, optical density, can be broadened with the dual ion-beam deposition process. Also, one particular film property can be changed independently of other set of properties with the dual ion-beam process.
Dual Ion-Beam Deposition Process
The ion-beam process embodies in photomask manufacture a process with fewer added (defect) particles, greater film density with superior opacity, and superior smoothness with reduced optical scattering, especially critical for lithographic wavelength  less than 400 nm. The dual ion gun configuration is shown schematically in FIG. 1. In this process, an energetic beam of ions (usually neutralized by an electron source) is directed from a deposition gun (1) to a target (2) which is sputtered when the bombarding ions have energy above a sputtering threshold, typically xcx9c50 eV. The ions from the deposition-gun are usually from an inert gas source such as He, Ne, Ar, Kr, Xe, although reactive gases such as O2, N2, CO2, F2, CH3, or combinations thereof, can also be used. When these ions are from an inert gas source they sputter the target material (2), e.g. Cr metal, which deposits as a film on the substrate (4). When these gas ions are from a reactive source, e.g. oxygen, they can chemically combine at the target surface and then the product of this chemical combination is what is sputtered and deposited as a film on the substrate. In dual ion beam deposition, energetic ions from a second gun or assist source bombard the substrate. Commonly, ions from the assist gun (6) are selected from the group of reactive gases such as, but not restricted to O2, N2, CO2, F2, CH3, or combinations thereof, which chemically combine at the substrate with the flux of material sputtered from the target (2). Therefore, if Ar ions from the deposition gun (1) are used to sputter a Cr target while oxygen ions from the assist source bombard the growing film, the Cr flux will chemically combine with energetic oxygen ions at the substrate, forming a film of chrome oxide.
Commonly, the bombarding ions from the deposition source should have energies of several hundred eVxe2x80x94a range of 200 eV to 10 KeV being preferred. The ion flux or current should be sufficiently high ( greater than 1013 ions/cm2/s) to maintain practical deposition rates ( greater than 0.1 nm/min). Typically, the process pressure is about 10xe2x88x924 Torr, with a preferred range 10xe2x88x923-10xe2x88x925 Torr. The preferred target materials of this invention are elemental Cr, Mo, W, Ta or their compounds. The substrate can be positioned at a distance and orientation to the target that optimize film properties such as thickness uniformity, minimum stress, etc. The energy of ions from the assist gun (6) is usually lower than the deposition gun (1). The assist gun provides an adjustable flux of low energy ions that react with the sputtered atoms at the growing film surface. For the xe2x80x9cassistxe2x80x9d ions, lower energy typically  less than 500 eV is preferred, otherwise the ions may cause undesirable etching or removal of the film. In the extreme case of too high a removal rate, film growth is negligible because the removal rate exceeds the accumulation or growth rate. However, in some cases, higher assist energies may impart beneficial properties to the growing film, such as reduced stress, but the preferred flux of these more energetic ions is usually required to be less than the flux of depositing atoms.
In dual ion beam deposition of photomask blanks the gas ion source for the deposition process is preferably selected from the group of inert gases including, but not restricted to He, Ne, Ar, Kr, Xe or combinations thereof, while the gas ion source for the assist bombardment is preferably selected from the group of reactive gases including, but not restricted to O2, N2, CO2, F2, CH3, or combinations thereof. However, in special circumstances the deposition gas source may also contain a proportion of a reactive gas, especially when formation of a chemical compound at the target is favorable for the process. Conversely, there may be special circumstances when the assist gas source is comprised of a proportion of an inert gas, especially when energetic bombardment of the growing film is favorable for modifying film properties, such as reducing internal film stress.
The capability to grow oxides or nitrides or other chemical compounds with a separate assist ion gun that bombards the growing film with a low energy, but high flux of oxygen or nitrogen ions is unique to the IBD process and offers precise control of film chemistry and other film properties over a broad process range. Additionally, in a dual ion beam deposition the angles between the target, the substrate, and the ion guns can be adjusted to optimize for film uniformity and film stress, whereas the geometry in magnetron sputtering is constrained to a parallel plate electrode system.
With the dual IBD process, any of these deposition operations can be combined to make more complicated structures. For example a CrOx/CrNy layered stack can be made by depositing from elemental Cr target as the film is successively bombarded first by reactive nitrogen ions from the assist gun, followed by bombardment with oxygen ions. When the layers in a stack alternate from an oxide to a nitride as in CrOx/CrNy, dual ion beam deposition with a single Cr target offers significant advantage over traditional magnetron sputtering techniques. Whereas the assist source in dual IBD can be rapidly switched between O2 and N2 as Cr atoms are deposited, reactive magnetron sputtering produces an oxide layer on the target surface that must be displaced before forming a nitride-rich surface for sputtering a nitride layer.
While it is possible to make films with complex chemical compounds, such as Si3N4, with ion beam deposition using a single ion source, the process is more restrictive than for dual ion beam deposition. For example, Huang et al. in xe2x80x9cStructure and composition studies for silicon nitride thin films deposited by single ion beam sputter depositionxe2x80x9d Thin Solid Films 299 (1997) 104-109, demonstrated that films with Si3N4 properties only form when the beam voltage is in a narrow range about 800 V. In dual ion beam sputtering the flux of nitrogen atoms from the assist source can be adjusted independently to match the flux of deposited target atoms from the deposition ion source over a wide range of process conditions and at practical deposition rates.
This invention relates to the dual ion beam deposition process for depositing a single layer or multiple layers of chromium, molybdenum, tungsten, or tantalum compounds of the general formula of, MOxCyNz where M is chromium, molybdenum, tungsten, or tantalum on quartz or glass substrate for manufacturing opaque photomask blanks.
This invention provides a novel deposition technique of single or multiple layer film for photomask blanks for incident wavelengths less than 400 nm. The substrate can be any mechanically stable material, which is transparent to the wavelength of incident light used. Substrates such as quartz, CaF2, and fused silica (glass) are preferred for availability and cost.
This invention provides dual ion-beam deposition of a single layer with a high optical density or opacity material where the chemistry is graded in the film thickness direction.
Preferably, this invention embodies dual ion-beam deposition of single or multiple layers of MOxCyNz, where M is selected from chromium, molybdenum, tungsten, or tantalum or combination thereof, where x ranges from about 0.00 to about 3.00, y ranges from about 0.00 to about 1.00, and z ranges from about 0.00 to 2.00.
Preferably, this invention embodies photomask blanks of the MOxCyNz type, where the optical density is more than about two units.
Optical Properties
The optical properties (index of refraction, xe2x80x9cnxe2x80x9d and extinction coefficient, xe2x80x9ckxe2x80x9d) were determined from variable angle spectroscopic ellipsometry at three incident angles from 186-800 nm, corresponding to an energy range of 1.5-6.65 eV, in combination with optical reflection and transmission data. From knowledge of the spectral dependence of optical properties, the film thickness, optical transmissivity, and reflectivity can be calculated. See generally, O. S. Heavens, Optical Properties of Thin Solid Films, pp 55-62, Dover, N.Y., 1991, incorporated herein by reference.

Ion-beam deposition process for manufacture of binary photomask blanks


The objective of the present invention is to provide a forging method that improves workability in machining, by turning the metallographical structure of products subject to impact load to a fine ferrite-perlite structure, without adopting the method of quenching and tempering, to obtain, as strength, a yield point (YP value) exceeding that obtained by the method of quenching and tempering, and making the tensile strength (TS) smaller compared with the method of quenching and tempering. A material to be forged has at least one kind of group 5 metal added thereto and is heated to a temperature suitable for hot forging. After forging to prescribed shape, cooling, and holding for a prescribed set time in a furnace at a tempering temperature, the material is further cooled to normal temperature by natural cooling.

The present invention relates to a forging method, more specifically a forging method that improves workability in machining by turning the metallographical structure of products subject to impact load to a fine ferrite-perlite structure, without adopting the method of quenching and tempering, to obtain as strength a yield point (YP value) exceeding that by the method of quenching and tempering, and making the tensile strength (TS) smaller than that obtained by the method of quenching and tempering.
Conventionally, products subject to impact load such as connecting rod, steering knuckle, crankshaft, etc., for example, used to be manufactured by forging.
Further, for the manufacturing of a connecting rod, which is momentarily subject to a large impact load, the method of quenching and tempering was also used in combination with forging, to increase its strength.
However, this method of quenching and tempering not only requires a high manufacturing cost but also is unfit for products mass-produced at low cost like automobile parts, for example, today when reduction of manufacturing cost is strongly called for. For that reason, a non-refining method capable of reducing manufacturing cost is coming to be adopted in place of the method of quenching and tempering.
This non-refining method consists of forcibly air cooling, after forging, high-temperature products from around 1200xc2x0 C. immediately to around 500xc2x0 C.
By the way, with the non-refining method by which high-temperature products at around 1200xc2x0 C. are forcibly air cooled, after forging, immediately to around 500xc2x0 C., the yield point (YP value) drops although the tensile strength (TS) remains at about the same level as with the method of quenching and tempering, and its value expressed by dividing the yield point by the tensile strength, i.e. value expressed in yield ratio (YR) is approximately 0.6. For that reason, this drop of yield point (YP value) as compared with the method of quenching and tempering puts an obstacle to reduction of weight of forged projects, while on the other hand a high tensile strength (TS) still remaining at about the same level as in the method of quenching and tempering means poor workability in machining in the same way as products manufactured by the method of quenching and tempering, and such were problems with the non-refining method.
In view of the problems with conventional forging methods, the objective of the present invention is to provide a forging method that improves workability in machining by turning the metallographical structure of products subject to impact load into a fine ferrite-perlite structure, without adopting the quenching and tempering method, to obtain, as strength, a yield point (YP value) exceeding that obtained by the quenching and tempering method, and reducing the tensile strength (TS) compared to the quenching and tempering method.
To achieve said objective, the forging method according to the present invention is characterized in that a forged material is manufactured by adding at least one kind of group metal, (or group VB metals), to a material to be forged, heating to a temperature suitable for hot forging, forging to a prescribed shape, cooling, holding for a prescribed set time in a furnace at a tempering temperature, and then further cooling to normal temperature by natural cooling.
In accordance with the present invention, it is desirable to set the xe2x80x9ctempering temperaturexe2x80x9d at a temperature in the range of 500xcx9c700xc2x0 C. and the xe2x80x9cprescribed set timexe2x80x9d for 30xcx9c60 minutes.
In this forging method, a forged material manufactured by adding at least one kind of group 5 metal to metal material consisting of perlite, ferrite, etc., which are usually used as forged materials, is heated to a temperature suitable for hot forging, is forged to a prescribed shape, is cooled, is then held for a prescribed set time in a furnace at a tempering temperature, and is then further cooled to normal temperature by natural cooling. Accordingly, group 5 metals such as vanadium, niobium, etc. that were added to the forged material can precipitate, on ferrite, fine carbon nitride mainly comprised of added elements, and thereby enable the setting of a high yield point (YP value) with high rigidity and strong resistance to impact load because of the fine metallographical structure of fine ferrite+perlite. The present invention therefore makes possible to reduce the weight of forged products, control a low tensile strength (TS), and thanks to the fine metallographical structure of fine ferrite+perlite, improve workability in machining, thus promoting the reduction of manufacturing costs for forged products.
In accordance with the present invention, the heating temperature of the forged material shall preferably be set in the range of 1150xcx9c1250xc2x0 C.
This promotes melting into a solid solution of group 5 metals such as vanadium, niobium, etc. that were added to the forged material. When they have cooled and precipitated, the texture of the forged material is strained with the precipitate, and precipitates as a large volume of fine carbon nitride, while the strength of the forged material increases because the metallographical structure becomes fine.


In a thin-film field-effect transistor having metal/insulator/semiconductor (MIS) structure, the semiconductor layer is formed of an organic compound, and the insulator layer is formed of an organic compound which is soluble in an organic solvent and exhibits spontaneous polarization similar to ferroelectric material. The transistor exhibits n-type transistor characteristics when polling is conducted by applying a voltage which is not less than a coercive electric field and not more than a withstand voltage between source and gate electrodes, and absent polling, the transistor exhibits p-type transistor characteristics.

Conventional thin-layer field-effect transistors (TFTs) utilizing silicon semiconductor or compound semiconductor are used in general integrated circuits and other expanding applications. While the number of new applications to which such devices are desirably applied is increasing, the requirements of lower cost and flexibility are imposed on these devices. To comply with such requirements, active research works have been made on organic semiconductors because of possible fabrication of devices having a variety of functions including low cost and flexibility. The implementation of organic semiconductors into a commercial practice will lead to the appearance of printable integrated circuits, electronic paper and the like. However, most organic semiconductors exhibit p-type behavior while only C60 and few other materials exhibit n-type behavior. N-type organic semiconductors are key materials for the establishment of organic electronic devices including p-n junctions.
In general, organic semiconductors are not prone to polarity inversion from p-type to n-type, because they have so great a band gap as compared with silicon semiconductor that no inversion layer is formed even when the band is deflected by applying an extra gate voltage. Although the inversion layer may be formed by inducing numerous carriers at the interface between the gate insulating film and the organic semiconductor, a high gate voltage can cause breakdown if a prior art gate insulating film is used. It is thus difficult to induce a sufficient quantity of carriers to provoke polarity inversion.
For instance, Appl. Phys. Lett., Vol. 85, p 3899 (2004) describes to use an aluminum oxide thin film having a high withstand voltage, high dielectric constant and low leakage current as the insulating film and a single crystal as the organic semiconductor. Allegedly the use of a single crystal as the organic semiconductor eliminates the influence of grains and trap level in the semiconductor thin film, and it is thus expected to gain a high mobility. Although the oxide insulator has the advantages of ease of thin film formation and a high dielectric constant, it undesirably has a low withstand voltage due to the essential presence of oxygen vacancies.

Ambipolar organic thin-film field-effect transistor and making method


Provided are a Tunneled Direct Link Setup (TDLS) establishment method for a TDLS initiator and a station supporting the establishment method. In the establishment method, a requesting Non-AP QSTA transmits a TDLS setup request frame via an access point(AP) to an intended peer Non-AP QSTA. And, the requesting Non-AP QSTA receives a TDLS setup response frame via the AP from the intended peer station in response to the TDLS setup request frame. And, the requesting Non-AP QSTA transmits a TDLS setup confirm frame via the AP to the intended peer station in response to the TDLS setup response frame.

1. Field of the Invention
The present invention relates to a wireless local access network (WLAN), and more particularly, to a direct link setup procedure in a tunneled direct link setup (TDLS) wireless network and a station supporting the direct link setup procedure.
2. Related Art
With the development of information communication technology, a variety of wireless communication technology has been developed. A wireless LAN (WLAN) is a technique permitting wireless access to its local network or Internet in specific service areas such as home or companies or air planes by the use of portable terminals such as a personal digital assistant (PDA), a laptop computer, and a portable multimedia player (PMP) on the basis of the radio communication technology.
These days, thanks to the increased availability of WLANs, portable terminal users such as laptop computer users are able to perform their tasks with increased mobility. For example, a user can take his laptop computer from his desk into a conference room to attend a meeting and still have access to his local network to retrieve data and have access to the Internet via one or more modems or gateways present on the local network without being tethered by a wired connection. Similarly, business travelers commonly use their portable terminals to gain access to their email accounts, to check if there is any unread email, and to read and send email.
In the initial WLAN technology, a data rate of 1 to 2 Mbps was supported by the use of frequency hopping, spread spectrum, and infrared communication using a frequency of 2.4 GHz. In recent years, with the development of the wireless communication technology, 54 Mbps in maximum can be supported by applying the Orthogonal Frequency Division Multiplex (OFDM) technology, etc. to the WLAN. In addition, the IEEE 802.11 has developed or is developing wireless communication technologies for improvement in quality of service (QoS), compatibility of an access point (AP) protocol, security enhancement, wireless resource measurement, wireless access in vehicular environment, fast roaming, mesh network, inter-working with external networks, wireless network management, and the like.
In the IEEE 802.11, a Basic Service Set (BSS) means a set of stations (STAs) successfully synchronized. A Basic Service Area (BSA) means an area including members of the BSS. The BSA can vary depending on propagation characteristics of a wireless medium and thus it may contain members of other basic service sets.
The BSS can be basically classified into two kinds of an independent BSS (IBSS) and an infra-structured BSS. The former means a BSS that constitutes a self-contained network and that is not permitted to access a Distribution System (DS). The latter means a BSS that includes one or more Access Points (APs) and a distribution system and that uses the APs in all the communication processes including communications between the Non-AP stations.
In the initial WLAN communication procedure, it was required that data is necessarily transmitted through the AP in the infra-structured BSS. That is, the direct transmission of data between non-AP stations (non-AP STAs) is not allowed in the infra-structured BSS. In recent years, a direct link setup (DLS) between the non-AP STAs supporting Quality of Service (QoS) has been introduced to improve the efficiency of wireless communications. Accordingly, in the BSS supporting the QoS, that is, in the QBSS including QoS STAs (QSTA) and QoS APs (QAP), the non-AP STAs can set up a direct link therebetween and directly communicate with each other through the direct link.
As described above, the existing DLS setup method is based on the premise that the BSS is the QBSS, which is a BSS supporting the QoS. In the QBSS, the AP as well as the non-AP STA is a QAP, which is an AP supporting the QoS. In the most WLAN environments currently used (for example, WLAN environments in accordance with the IEEE 802.11a/b/g), the non-AP STAs are QSTAs supporting the QoS but the APs are legacy APs not supporting the QoS. As a result, in the WLAN environments currently used, there exists a limitation that even a QSTA cannot utilize the DLS service.
A TDLS (Tunneled Direct Link Setup) is a wireless communication protocol newly suggested to overcome such a limitation regarding the existing DLS service. The TDLS allows the QSTAs to set up a direct link in the currently used WLAN environments in accordance with the IEEE 802.11a/b/g. Accordingly, the TDLS defines methods of allowing the QSTAs to set up a direct link even in the BSS managed by the legacy AP. Hereinafter, a wireless network supporting the TDLS method is referred to as a TDLS wireless network.
In the TDLS wireless network, it is first necessary to specifically define a method of setting up a direct link between two non-AP QSTAs. Particularly, in the TDLS wireless network, an AP does not support the direct link setup method and thus does not directly participate in the setup method of the direct link. Accordingly, there is a need for efficiently and reliably enabling the direct link setup method.
And, in the communication between non-AP QSTAs through the direct link set up, it is necessary to allow the QoS facilities of the non-AP QSTAs to work properly. In addition, when the non-AP QSTAs support High Throughput (HT) capabilities of IEEE 802.11n, it is preferable to allow the HT facilities of the non-AP QSTAs to work properly.

Direct link setup method in tunneled direct link setup wireless network and station supporting the method


According to one embodiment, a suspension assembly includes a support plate, a trace member attached to the support plate, and an actuation element configured to expand and contract, and fixed to the trace member. The trace member includes a proximal-end plate portion, a metallic plate including a division plate portion, an insulating layer including a bridge portion, a conductive layer to form a plurality of traces and a counter-plate provided on the bridge portion between the proximal-end plate portion and the division plate portion and opposing the actuation element via the insulating layer, and the actuation element is located on the bridge portion.

In recent years, disk devices such as magnetic disk drives and optical disk drives have widely been used as external storage devices of computers and image recording devices.
As such a disk device, for example, a magnetic disk drive generally comprises a magnetic disk provided in a base, a spindle motor which supports and rotates the magnetic disk, and a suspension assembly which supports a magnetic head. The suspension assembly includes a suspension attached to a distal end portion of an arm, a trace member (a flexure or a wiring trace) provided on the suspension and a load beam. The trace member includes a gimbal portion which supports the magnetic head, forming a head suspension assembly.
In more recent years, there is proposed a suspension assembly wherein a piezoelectric element (PZT element) serving as actuation element is mounted in the vicinity of a gimbal portion of a trace member, and a magnetic head is minutely displaced in a seek direction by expansion and contraction of the piezoelectric element. According to the suspension assembly, the operation of the magnetic head can be minutely controlled by controlling a voltage to be applied to the piezoelectric element.
In the suspension assembly, the piezoelectric element is fixed by its entire surface to the trace member. But when the PZT element expands or contracts, it bends in its thickness direction in some cases, which may produce vibrations in directions crossing the expansion/contraction directions (out-of-plane vibration). The out-of-plane vibration is propagated to the suspension via contact points of the trace member, and may excite resonance of the suspension. As a result, the accuracy of positioning the magnetic head is reduced.

Suspension assembly, head suspension assembly and disk device with the same


In a receiver, a mixer portion provided in a front-end portion thereof is built with two mixers with different input/output linearity characteristics and different current consumption. According to the electric-field strength of a received signal, or manually, one of the mixers is chosen to operate so that, when the electric-field strength is in an ordinary range, the mixer with a better input/output linearity characteristic is chosen to operate with lower current consumption and, when the electric-field strength is in a high range, the mixer that, despite operating with higher current consumption, exhibits a still better input/output linearity characteristic is chosen. The receiver thus operates with lower current consumption and lower signal distortion.

1. Field of the Invention
The present invention relates to a receiver, and more particularly to a receiver incorporating a mixer that converts a received radio-frequency signal into a signal having a predetermined frequency.
2. Description of Related Art
In general, a receiver employing a radio-frequency wireless system such as satellite broadcast, satellite communication, or wireless telephony receives a radio-frequency signal in the GHz band to reproduce an original signal therefrom. FIG. 8 is a block circuit diagram of a typical front-end portion of a radio-frequency circuit used in such a receiver.
A radio-frequency signal received via an antenna 120 of a receiver is fed, via an input terminal 101 of a front-end portion 110, to a low-noise amplifier 102 that amplifies the radio-frequency signal, which is in the GHz band. The amplified radio-frequency signal is then fed to one input terminal of a mixer 106 provided in the succeeding stage. To the other input terminal of this mixer 106 is fed, from a local oscillator 104, a local oscillation signal having a frequency different from that of the received radio-frequency signal. As a result, an intermediate-frequency signal having a frequency equal to the difference between the frequency of the received radio-frequency signal and that of the local oscillation signal is outputted from the mixer 106 to an output terminal 105. This intermediate-frequency signal is then amplified by an intermediate-frequency amplifier 130 provided in the succeeding stage, and is then subjected to predetermined processing for signal reproduction.
Incorporating the front-end portion 110 configured as described above, the receiver has the following problem. The input/output linearity characteristic of the low-noise amplifier 102, in particular that of the mixer 106, greatly affects the distortion that the signal suffers in the receiver. That is, with a poor input/output linearity characteristic, when a signal with a high electric-field strength is received, the signal obtained by receiving that signal suffers distortion.
FIG. 9 is a diagram schematically showing the input/output characteristic of a mixer that is commonly used in a radio-frequency circuit to produce an intermediate-frequency signal. A receiver is required to be capable of receiving a signal of which the electric-field strength varies in a wide range. Thus, in the receiver, a signal of which the electric-field strength varies in a wide range is amplified by a low-noise amplifier having a predetermined gain, and is then fed to a mixer. In FIG. 9, the horizontal axis represents the signal strength of the signal that is fed to the mixer, which signal strength is referred to as the input signal strength. The input signal strength is proportional to the electric-field strength of the received radio-frequency signal. The vertical axis, on the other hand, represents the signal strength of the intermediate-frequency signal that is outputted from the mixer, which signal strength is referred to as the output signal strength.
In FIG. 9, the range indicated by C is the range of the input signal strength of the mixer, i.e., the range in which the input signal strength is proportional to the received electric-field strength. The input/output linearity characteristic curve P11 indicates an ideal linear relationship between the input and output signal strengths. By contrast, the input/output linearity characteristic curve P12 indicates the input/output linearity characteristic actually observed with a mixer 106 commonly used, for example, in a conventional front-end portion 110 as shown in FIG. 8. A mixer should ideally exhibit a linear relationship over the entire range C as indicated by the input/output linearity characteristic curve P11. In reality, however, a commonly used mixer, while exhibiting a close-to-linear characteristic in an ordinary-input-signal-strength range A, i.e., the range where the input signal strength is ordinary, exhibits a non-linear characteristic in a high-input-signal-strength range B, i.e., the range where the electric-field strength, and thus the input signal strength, is high.
For this reason, in a front-end portion incorporating a single-gain low-noise amplifier, when a signal having a high electric-field strength is received, in the stage succeeding the low-noise amplifier, the intermediate-frequency signal suffers distortion mainly attributable to the input/output linear characteristic of the mixer, with the result that the data carried by the signal is damaged. One solution to this problem is to design the front-end portion, in particular the mixer, to exhibit an ideal linearity characteristic over the entire range C mentioned above. Undesirably, however, designing the mixer that way results, as an inevitable consequence attributable to the characteristics of a transistor, increased current consumption by the transistor. In particular in portable wireless telephones and portable wireless communication apparatuses such as personal digital assistants incorporating wireless communication circuits, minimizing the current consumption is one of the important challenges.
For this reason, reduction of signal distortion is often attempted by lowering the gain of a low-noise amplifier when a signal having a high electric-field strength is fed to the low-noise amplifier. This is exemplified by the technique disclosed in Japanese Patent Application Laid-Open No. H7-30445. According to this technique, the electric-field strength of a received signal is detected, and, if the detected electric-field strength is higher than a predetermined value, the gain of a low-noise amplifier is lowered.
Varying the gain of a low-noise amplifier, however, requires the use of a variable-gain low-noise amplifier. A variable-gain low-noise amplifier, to permit the gain thereof to be varied, requires many extra circuits, and is thus more likely to generate noise than a fixed-gain low-noise amplifier. Moreover, even a variable-gain low-noise amplifier is not free from conventionally experienced problem when fed with a signal having an electric-field strength higher than it can cope with.


Parts of the body of a user can be used as surfaces for rendering content, such as augmented reality (AR) content. A computing device executing an AR application can detect body parts in an augmented reality view, such as a hand within a field of view of a camera capturing image data for the application. A type of content to be displayed can be determined based on the type and orientation of the body part, in addition to the location and orientation of the device. The content can vary with changes in the orientation of the body part or motion to cause another body part to be visible. A user can make a selection or input for the content by contacting the surface of the body part onto which the content is projected, providing tactile feedback to the user as well as a determinable action for the device.

The widespread adoption of portable computing devices, such as smartphones and tablet computers, has resulted in a corresponding increase in the amount and types of electronic content available to users. This includes the providing of augmented reality (AR) content, where image data can be captured for a location and a computing device can render content such that the content appears, at least as displayed on a screen of the device, that the content exists in that physical location. In many situations the device performing the rendering will attempt to determine an appropriate surface or object to use as a location for displaying the AR content. There will not always be appropriate surfaces or objects available, and displaying AR content at a distance from physical objects or surfaces detracts from the perceived realism of the augmented reality experience.

Using body surfaces for placing augmented reality content


A method for cleaning a microwave plasma processing apparatus which has a processing container and a microwave radiation part, and which has a window part provided at a position where the microwave radiation part is disposed in the processing container, includes a cleaning step of adjusting a pressure to a pressure corresponding to a size of a cleaning target part, among parts within the processing container including a wall surface of the processing container, the microwave radiation part, and the window part, while supplying a cleaning gas, and performing a cleaning process using plasma of the cleaning gas.

Patent Document 1 proposes a cleaning method including a first step of generating plasma while supplying a cleaning gas into a processing container so as to maintain the interior of the processing container at a first pressure and to perform cleaning, and a second step of maintaining the interior of the processing container at a second pressure higher than the first pressure and performing cleaning.
Patent Document 2 discloses a cleaning method including step 1 of cleaning the interior of a processing chamber and a member accommodated in the processing chamber, step 2 of cleaning the lower portion of each of the interior of the processing chamber and the member, and step 3 of cleaning the interior of a gas supply path. Step 1 is performed by setting the pressure in a first pressure zone and the temperature in a first temperature zone, and supplying a cleaning gas from the gas supply path. Step 2 is performed by setting the pressure in a second pressure zone higher than the first pressure zone and supplying the cleaning gas from the gas supply path while raising the temperature in a second temperature zone higher than the first temperature zone. Step 3 is performed by setting the pressure in a third pressure zone lower than the second pressure zone and supplying the cleaning gas from the gas supply path while maintaining the temperature in the second temperature zone.


A poly-silicon layer of a thin film transistor (TFT) having an active channel region, wherein a probability P that a maximum number of a primary grain boundary exists on the active channel region is not 0.5, the probability obtained by the following equation:       P    =                  D        -                              (                                          N                                                  xe2x80x83                                                max                            -              1                        )                    ·          Gs                    Gs        ,

This application claims the benefit of Korean Application No. 2001-74375, filed Nov. 27, 2001 in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a poly-silicon layer and a device having the same, and more particularly, to a poly-silicon layer of a thin film transistor (TFT) and a device having the same.
2. Description of Related Art
An active channel region of a thin film transistor (TFT) is generally made of a poly-silicon material and so includes grain boundaries. In the grain boundaries, defects such as dangling bonds and strained bonds exist, and such defects act as traps of the charge carriers.
Therefore, parameters such as grain size, grain-size uniformity, number of grains, locations of grain boundaries, and tilt angle of grain boundaries affect characteristics of the TFT such as threshold voltage, sub-threshold slope, charge carrier mobility, leakage current, and device stability. In particular, the tilt angle of the grain boundaries affects uniformity in characteristics of the TFTs.
The grain boundary which adversely affects characteristics of the TFT is referred to as a primary boundary. The number of the primary boundaries existing on the active channel region depends on a grain size and a tilt angle xe2x80x9cxcex8xe2x80x9d of a grain boundary and a dimension (i.e., length L and width W) of the active channel region, as illustrated in FIG. 1.
Assuming that the maximum number of the primary grain boundaries which can exist on the active channel region with a given channel length is xe2x80x9cNmaxxe2x80x9d, the number of the primary grain boundaries existing on an arbitrary active channel region with the same channel length can be either xe2x80x9cNmaxxe2x80x9d or xe2x80x9cNmaxxe2x88x921xe2x80x9d.
Referring to FIGS. 2A and 2B, the TFT of FIG. 2A has two primary boundaries, and the TFT of FIG. 2B has three primary boundaries.
In a display device, as the TFTs having the same number of primary boundaries become more dominant, the display device having an excellent TFT characteristic uniformity can be achieved. However, when the TFTs having Nmax primary-boundaries and the TFTs having xe2x80x9cNmaxxe2x88x921xe2x80x9d primary-boundaries are equal in number, the display device has a worst uniformity in TFT characteristics.
Meanwhile, the active channel region having large silicon grains can be formed using a sequential lateral solidification (SLS) technique. The TFT manufactured by employing such an active channel region shows similar characteristics to those of the TFT manufactured by using a single crystalline silicon.
However, a display device includes millions of pixels. A liquid crystal display (LCD) device includes one TFT per one pixel, and an organic electroluminescent (EL) display device includes at least two TFTs per one pixel. Therefore, it is impossible to manufacture millions of TFTs that are all equal in number of the primary grain boundaries existing on the active channel region and in the grain growth direction.
International Patent No. WO 97/45827 discloses a technique to form an active channel region having large silicon grains using the SLS technique. An amorphous silicon layer is deposited using a PECVD technique, an LPCVD technique, or a sputtering technique. Thereafter, the entire portion or a selected portion of the amorphous silicon layer is crystallized using the SLS technique, as illustrated in FIGS. 3A and 3B.
During a crystallization of the entire portion or a selected portion of the amorphous silicon layer, a laser beam or a stage can be stepped up or down, or shifted. Therefore, a misalignment between regions scanned by the laser beam occurs, resulting in a different number of primary grain boundaries in the active channel region from TFT to TFT. Although there is no misalignment error on the entire panel during crystallization, there would always be a different number of the primary boundaries from TFT to TFT depending on the position and dimension of TFTs on the panel unless the position and dimension of TFTs are designed to control the number and position of the primary grain boundaries, which complicates both the TFT design and the fabrication process. Thus, the number of primary grain boundaries included in the active channel region of the individual TFTs can differ from each other, leading to bad uniformity in TFT characteristics.
U.S. Pat. No. 6,177,301 discloses a method of manufacturing a TFT, wherein the active channel region of the TFT having large silicon grains is formed using the SLS technique. When a channel direction is parallel to a grain growth direction, as illustrated in FIG. 4A, a barrier effect of the grain boundary for a charge carrier direction is minimized, whereupon the TFT can have a characteristic similar to the single crystalline silicon. However, when a channel direction is perpendicular to a grain growth direction, as illustrated in FIG. 4B, the grain boundaries act as a trap of the charge carriers, whereupon a characteristic of the TFT greatly deteriorates.
Actually, the TFTs of which channel direction is perpendicular to a grain growth direction can be manufactured. In this case, a characteristic uniformity of the TFTs can be improved without greatly lowering the characteristics of the TFTs by tilting an angle of a channel direction to a grain growth direction by 30xc2x0 to 60xc2x0. However, this method cannot remove the primary boundaries completely from the active channel region, and thus the non-uniformity in the TFT characteristics due to the differing number of the primary grain boundaries still exists.
Accordingly, it is an object of the present invention to provide a poly-silicon layer which can provide thin film transistors having uniform characteristics.
It is another object of the present invention to provide a display device having uniform characteristics.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention are achieved by providing a poly-silicon layer of a thin film transistor (TFT) comprising an active channel region, wherein a probability P that a maximum number of a primary grain boundaries exist on the active channel region is not 0.5, the probability obtained by the following equation:       P    =                  D        -                              (                                          N                                                  xe2x80x83                                                max                            -              1                        )                    ·          Gs                    Gs        ,
where D=L cos xcex8+W sin xcex8, L is a channel length of the active channel region, W is a width of the active channel region, Nmax is the maximum number of the primary boundaries existing on the active channel region, Gs is a grain size, and xcex8 is a tilt angle of the primary grain boundary.
The foregoing and other objects of the present invention are also achieved by providing a poly-silicon layer of a thin film transistor (TFT) comprising an active channel region, wherein a length of the active channel region is an integer multiple of a grain size.
The foregoing and other objects of the present invention are also achieved by providing a poly-silicon layer of a thin film transistor (TFT) comprising an active channel region, wherein a probability that a maximum number of primary grain boundaries exists on the active channel region is defined as a ratio of the distance in which the length of the active channel in the longitudinal direction of grains minus a distance that a xe2x80x9cmaximum numberxe2x80x941xe2x80x9d of primary grain boundaries occupy, to the longitudinal length of the grains, and the probability is not 0.5.
The foregoing and other objects of the present invention are also achieved by providing a device having a thin film transistor having the poly-silicon layer of one of the poly-silicon layers of the present invention.

Poly-silicon layer of a thin film transistor and display device having the same

Abstract: where D=L cos xcex8+W sin xcex8, L is a channel length of the active channel region, W is a width of the active channel region, Nmax is the maximum number of the primary boundary existing on the active channel region, Gs is a grain size, and xcex8 is a tilt angle of the primary grain boundary and the display device having thereof.