Disclosed is a control element or switching element that is provided with elements which electrically or chemically respond to the sense of touch, for example in a steering wheel. The elements are used for supplying the driver who touches the elements with warnings and/or information about the state of the vehicle or traffic. Interactive functions can be connected thereto, by means of which replies by the driver can be detected and processed. The driver can consequently cause the information system of the vehicle to also represent the warning information in an optical manner, e.g. in corresponding control lights on the dashboard, at a desired time.

In motor vehicles a series of information systems is installed which comprise a specific sensor or detector and associated display which is usually installed in the dashboard. Such displays are the speedometer, the temperature display of the cooling system, fuel tank display, oil pressure warning lamp, engine speed meter and a series of monitoring lights for the parking brake, doors which are open and the like. In addition there is a series of proposals for displaying general hazardous situations in the field of vision of the driver. These include displays which relate to distance warning systems (distance radar) and the like.
The disadvantage of such systems is that movements of the head and eyes are necessary in order to detect the visual signals and intellectual effort has to be expended since in an individual case it is necessary to recognize which hazardous situation or which deficiencies of the vehicle are being indicated by the respective display. In each case, the driver is distracted, or his attention is at least briefly impaired, by the perception of a visual display and the assignment of its significance. This results in a prolonged reaction time to changed traffic conditions. This is associated with considerable disadvantages in particular when driving in the dark or in the rain.
It is known from toys and gaming machines that haptic impressions can also be conveyed in addition to visual impressions. However, in gaming machines such (haptic) stimulations which relate to the sense of touch and sensory perceptions are as :a rule snot conveyed at the same time as the visual impressions. For this reason, such haptic stimulations are not a supplement to the visual impression but rather additionally induced sense impressions which are perceived as a consequence of or as an accompanying circumstance of the visual impressions.
On an Internet website www.wissenschaft.de/sixcms, "bild der wissenschaft online", a technical report was published on Mar. 11, 2001 which describes how vehicle monitoring systems in the field of passenger car safety can be configured by means of a computer. In this context, the closing of the eyelids and the movements of the eyes of the driver are monitored and possible accidents as a result of the driver sleeping for a few seconds are prevented or other adverse effects on the driver are avoided. The system has what is referred to as a face model. It compares stored and current facial structures pixel by pixel with various resolutions. As a result, faces or parts of the face can be determined and compared with stored data.

Control element or switching element for vehicles


A highway coupling apparatus includes an expansion joint template, a plurality of rods, and a plurality of pipes. The template is positioned between longitudinal forms of a highway lane, creating two sections. After positioning the reinforcement bar in each section, the rods are extended through the expansion joint template and movably coupled to the pipes located in the second section. The highway coupling apparatus also includes a movement joint to couple adjacent lanes of the highway. The movement joint includes a plurality of eye bolts, L-bolts, movement joint templates, and a movement joint form. The eye bolts and L-bolts partially extend from the respective first and second lanes into the movement joint templates and are coupled. The movement joint templates are coupled to the movement joint form and prevent concrete from entering the eye bolt eyes during fabrication. After concrete is poured into the lanes and allowed to set, the expansion joint template and movement joint form are removed, resulting in an expansion groove and a movement joint groove. The grooves extend the entire depth of the highway and are filled with pitch to allow relative movement of the highway sections and lanes.

Under current practice in highway construction, twelve foot wide concrete lanes are poured in continuous lengths. Prior to pouring the concrete, forms are positioned to define the shape of the lane and metal reinforcement bars are placed within the forms. Reinforcement bars, or rebar, is placed on supports so that the rebar will be located at a depth of about the middle of the concrete. After the concrete has been poured and initially set, transverse cuts are made across the width of each lane at various intervals. The initial cut is about one inch wide and extends about one-half the depth of the concrete. The purpose of the cut is to weaken the concrete and cause the concrete to crack in the plane of the cut through the full depth of the concrete, thereby forming two abutting sections of highway. After the concrete is fully cured, the initial cut is then widened to about two inches, forming a groove. An expansion joint is then inserted in the groove. The expansion joint may be an extruded neoprene, pitch, or a semi-liquid material such as tar which is poured into the groove.
In multiple lane highways, additional lanes of highway are formed adjacent to the first lane. The additional lanes are formed in a manner similar to the first lane, however, the second lane is poured using the first lane as a longitudinal form. The lanes are formed without any coupling between the lanes so that each lane moves independent of the other lane. Shoulder lanes are formed adjacent to the outer lanes.
While the above described structure allows relatively minor elevation changes in the abutting sections of the highway, such structure does not readily accommodate expansion of the highway sections. While, the initial cut made in the highway creates two abutting sections of highway, the cut extends only one-half of the depth of the concrete, therefore the two sections cannot expand. Although the top half of one section of the highway is spaced away from another section, the lower half of each section remains fully against the other section. Therefore, each section may rise and fall relative to the other section but cannot expand without pushing against the other section. Any expansion of the highway sections causes the highway to buckle, or erupt, resulting in significant structural damage to the highway. Additionally, such method is labor intensive and time consuming. Particularly, each lane of the highway must be cut at least twice and the groove must be thoroughly cleaned to remove any foreign objects or materials before the expansion joint is inserted. In addition, as a result of cutting only one-half of the highway depth, it is possible that the highway will crack in a plane other than that of the cut resulting in substantial structural damage to the highway.
It would be desirable to provide a highway coupling apparatus which is easy to install that would couple sections of highway without requiring the cutting of the highway. It would further be desirable to provide such an apparatus that provides an expansion joint extending the fall depth of the highway. Additionally, it would be desirable to provide an apparatus which couples parallel highways sections while preventing separation of the highway sections.


An on-chip bus includes a plurality of switch points including first and second switch points, a plurality of inter-switch links including at least one inter-switch link coupled between the first switch point and the second switch point and configured to communicate data between the first switch point and the second switch point, and a plurality of functional block cores including first and second functional block cores coupled directly to the first switch point and configured to communicate data through the first switch point. Data transmitted from the first functional block core to the second functional block cores may pass through the first switch point without traversing any of the plurality of inter-switch links. Methods for communicating data on an on-chip bus are also disclosed.

In the chipset design concept, a computing system may include a set of related functional chips that are designed and produced to be used together. In contrast, chipset technology has recently progressed toward a system-on-chip (SOC) concept in which various functional blocks, previously provided on related individual chips, are integrated onto a single semiconductor chip.
The SOC concept integrates various functional block cores such as, for example, a microprocessor, an on-chip memory, an audio controller, a video controller, a coder and decoder (codec), and/or a digital signal processor (DSP), on a single chip, thereby potentially reducing the total product size, time, and/or cost required for developing a system including the functional block cores.
A functional block core used in an SOC system can be developed independently or can be provided by a core that has been already developed. This reusability of functional block cores may save development time and/or cost.
For data-intensive applications such as the processing of broadband video and/or audio, it may be desirable to provide a large bandwidth for data communication between some of the functional block cores. Accordingly, the expected data traffic load between functional block cores may increase.
For example, in the case of an SOC system in which a large-capacity on-chip memory or a controller (or codec) for processing audio/video signals is built, a large development effort may be required to enable a sufficient level of data communication between functional block cores.
Generally, a bus is used for transferring data between many chips. For example, in an embedded system using an Advanced RISC Machine (ARM) CPU, functional units such as a CPU, a memory controller, and/or a display controller may be connected by a bus architecture such as an Advanced Microcontroller Bus Architecture (AMBA).
In some cases, the functional block cores in an SOC system may be connected by the AMBA bus architecture. For example, in the case of a conventional low-integrated SOC system, a chip-level bus architecture may be used without significant alteration.
However, in a highly integrated SOC system, the width of wires in the system bus may be narrowed. Accordingly, the inductance, resistance and capacitance of the bus wires may be increased in comparison with the size of gates in the functional block core. Consequently, when a conventional bus architecture is used in a highly integrated SOC system, it may be difficult to achieve a desired level of system performance.
Accordingly, interest has developed in a Network-On-Chip (NOC) concept including an efficient on-chip bus architecture corresponding to the SOC concept and associated design methodology. Various on-chip bus architectures have recently been proposed.
A conventional on-chip bus architecture 100 is illustrated in FIG. 1. The architecture 100 is a type of bus architecture usable in an SOC architecture including nine functional block cores 110a-110i, and is a slight modification of a bus structure disclosed in U.S. Pat. No. 5,974,487.
Referring to FIG. 1, a conventional on-chip bus architecture 100 includes nine functional block cores 110a-110i configured to perform various functions, switch points 120a-120l operable to mediate (or relay) data communication between the functional blocks cores 110a-110i, and inter-switch links 130a-130l and 131a-131h interconnecting the switch points 120a-120l.
The inter-switch links 130a-130l, 131a-131h and the switch points 120a-120l are configured in a two-dimensional mesh 140 of rings within the overall bus architecture 100.
The switch points 120a-120l are positioned at interconnections of the mesh 140. Each of the switch points 120a-120l receives data from a source switch point through an inter-switch link and transfers the received data to a destination switch point through an appropriate inter-switch link.
Further, each of the switch points 120a-120l may receive data from a source switch point through an inter-switch link and then transfer the received data to a functional block core connected thereto. Each switch point may receive data from a connected functional block core and transfer the received data to a destination functional block core through a corresponding inter-switch link via an appropriate switch point.
Each of the inter-switch links 130a-130l, 131a-131i may be a bi-directional link or a unidirectional link. A bi-directional link may include a pair of uni-directional wires having opposite communication directions or, alternatively, one bi-directional wire.
In the above-described on-chip bus architecture 100, when the functional block core 110a needs to transfer data to the functional block core 110e, the functional block core 110a transfers the data to the switch point 120a connected thereto.
The switch point 120a receives the data from the functional block core 110a and transfers the received data to the switch point 120d through the inter-switch link 131a connected between the switch points 120a and 120d. The switch point 120d receives the data from the switch point 120a through the inter-switch link 131a and finally transfers the received data to the functional block core 110e connected thereto.
That is, in the on-chip bus architecture 100, data communication between functional block cores 110a-110i is performed through the switch points connected respectively to the functional block cores 110a-110i and inter-switch links 130a-130l, 131a-131h that connect the switch points 120a-120l.
FIG. 2 is a block diagram of a conventional switch point 200 used in the mesh-based on-chip bus architecture 100, which is disclosed in "A Network on Chip Architecture and Design Methodology", Proc. ISVLSI 02, April 2002.
Referring to FIG. 2, a conventional switch point 200 includes a plurality of switch ports 220a-220d, which include incoming links 213a-213d, outgoing links 214a-214d, queues 210a-210d for queuing data received through the incoming links 213a-213d, multiplexers (MUXs) 211a-211d for outputting received data over a selected outgoing link 214a-214d, and selection logic units 212a-212d for controlling the multiplexers 211a-211d.
The incoming links 213a-213d and outgoing links 214a-214d together make up bi-directional inter-switch links. That is, the bi-directional inter-switch links include the incoming links 213a-213d for receiving data into the switch point 200 from the outside and the outgoing links 214a-214d for transferring data from the switch point 200 to the outside.
As illustrated in FIG. 1, the switch points 120a-120l are positioned at the interconnection points of the mesh 140. Each of the switch points 120d, 120e, 120h and 120i is connected to four inter-switch links, respectively, while each of the switch points 120a, 120b, 120c, 120f, 120g, 120j, 120k and 1201 is connected to three inter-switch links, respectively.
Referring again to FIG. 2, the switch point 200 has a structure corresponding to one of the switch points 120d, 120e, 120h and 120i, each of which is connected to four inter-switch links. In particular, the switch point 200 has a structure corresponding to one of the switch points 120h and 120i, whose left lower end is connected to a functional block core 110g, 110h.
Data received from another switch point through one of the incoming links 213a-213d is inputted to one of the queues 210a-210d, and data outputted from the queue 210a-210d is selected by at least one of the remaining switch ports 220a-220d and is outputted via an outgoing line 214a-214d. In order to perform this mediation function, each switch port 220a-220d of the switch point 200 is provided with a multiplexer 211a-211d for selecting one of the incoming data queues 210a-210d which receives data from the other switch points, and outputs data through an associated inter-switch link.
For example, in order to determine data to be outputted through the outgoing inter-switch link 214d, the multiplexer 211d selects data that is received through one of the remaining three inter-switch links 213a-213c and is queued in one of the queues 210a-210c. The multiplexer 211d is controlled by the selection logic unit 212d.
The switch point 200 further includes a bus interface port 220e connected to an interface of a functional block core (not shown) connected thereto.
The bus interface port 220e includes a queue 210e for queuing data received from the connected functional block core, a multiplexer 211e for selectively transmitting data from the inter-switch links 213a-213d to the functional block core, and a selection logic unit 212e for controlling the multiplexer 211e.
The on-chip bus architecture 100 using the switch point 200 may be advantageous in that it may be modular and easy to extend, and may have a short link length.
However, the on-chip bus architecture 100 may be disadvantageous in that the on-chip bus architecture 100 may have to use an inter-switch link even for data communication between the functional block cores positioned close to each other.
Accordingly, the power consumption and communication delay of the on-chip bus architecture 100 may undesirably increase in proportion to the number of inter-switch links used in the bus architecture 100.

On-chip bus architectures with interconnected switch points, semiconductor devices using the same and methods for communicating data in an on-chip bus architecture


The invention provides a radical generator, although being a self-cleavage type initiator, which is capable of suppressing volatilization of low molecular weight decomposition materials at the time of light radiation and post-baking, and leaving no low molecular weight decomposition materials in the final product, a photosensitive resin composition and an article using the radical generator. The photoradical generator provided according to the invention contains a compound (a) having one or more self-cleavage type radical-generating parts and one or more ethylenic unsaturated groups in one molecule.

1. Field of the Invention
The present invention relates to a photoradical generator comprising a compound comprising molecular structure having self-cleavage type radical-generating parts and ethylenic unsaturated groups, a photosensitive resin composition containing the generator, and an article produced from the resin composition.
Particularly, the invention relates firstly to a photoradical generator which itself has a function as a photoradical initiator and a function as a polymerizable compound and a self-cleavage type high reaction potential (high sensitivity) as well as fixation capability of the cleavage parts of the photoradical initiator in a matrix and is excellent in compatibility with monomer components.
Secondarily, the invention relates to a photosensitive resin composition containing the radical generator and being capable of decreasing the odor (outgas) at the time of exposure or post-baking and lessening volatile low molecular weight decomposition materials, particularly odorous components, remaining in a product after curing.
Thirdly, the invention relates to an article of which at least a portion is made of the cured product of the photosensitive resin composition and which has high heat resistance and stability so as to be scarcely deteriorated with heat.
2. Description of the Related Art
Photosensitive resins to be cured or to have solubility by light irradiation of UV rays or the like are generally classified into two types; those having exposed parts with good solubility (positive type) and those having unexposed parts with good solubility (negative type). In the case of the negative type, since the photosensitive resins themselves are cured and become insoluble by exposure, the photosensitive resins themselves often remain on substrates to from portions of products as functional films.
Although the negative type photosensitive resin has been used for, for example, paints, printing inks, overcoat layers, adhesives, printing master plates or the like, it has been recently used in wide applications ranging to products such as solder resists for wire protection in printed wiring boards, layer insulation films and resists for forming pixels in color filters, antireflection films, hologram or the like.
One of generally popular negative type photosensitive resins includes a resin composition containing a compound having one or more ethylenic unsaturated bonds, a photoradical initiator for generating radicals by light irradiation, and if necessary, a macro molecular compound, an inorganic filler, a pigment or the like for providing developing ability and softness of coating layer. When light is irradiated to the composition, the molecules of the compound having the ethylenic unsaturated bonds are bonded by radical reaction to increase the molecular weight and be cured. At the time of the curing reaction, three-dimensional mesh structure is developed by the crosslinking reaction, so that the hardness, strength, adhesion property, solvent resistance, and heat resistance of the cured product to be obtained are increased.
Photoradical initiators are broadly classified into self-cleavage type (Type I), and non-self-cleavage type (Type II) (Photocuring technology, p. 39, Technical Information Institute Co., Ltd., 2000). In the case of the former, just like a benzoin ether type compound, the bonds at the positions corresponding to light with specified wavelength are cut by absorbing the light and radicals are generated at the respective cut positions at the moment and there radical reaction starts. In the case of the latter, such a radical initiator has a radical generation mechanism for generating radicals without decomposition at the time of absorption of light with the specified wavelength and, for example, in the case of a hydrogen-drawing type represented by benzophenone, it absorbs electromagnetic wave with specified wavelength and when elevated to excited state, it draws hydrogen from hydrogen donors in the surrounding and at that moment, radicals are generated in both of the drawing side and the drawn side.
In general, self-cleavage type radical initiators are good in the sensitivity and radical generation efficiency, however generate low molecular decomposition materials at the time of light irradiation and such low molecular decomposition materials cause odor by volatilization in the work environments or are condensed again after volatilization to result in pollution of production apparatus and inferior product production, or such low molecular decomposition materials remain in products to deteriorate heat resistance and stability of the products or are slowly released from the products.
On the other hand, the hydrogen-drawing type are free from the generation or remaining of the low molecular decomposition materials derived from the initiators, however, they require existence of hydrogen donors in the vicinity of the excited initiators or have relatively low sensitivity since their radical generation efficiency is determined depending on the energy barrier height at the time of drawing of hydrogen.
To say more practically, there may be the following problems of the self-cleavage type initiators to be encountered in the case of various uses.
Firstly, as an example, use for a solder resist or color resist can be exemplified. The solder resist to be used for surface coverage of a printed wiring board contains an organic pigment and a filler for providing heat resistance and flame resistance or the resist for pixel formation for a color filter contains a pigment for color display. Since these pigments are components absorbing light, they utilize mainly self-cleavage type photoradical initiators and are added in large quantities including the amount for vain use in radical reaction of them in order to increase the sensitivity of the photosensitive resins. Here, the portion which is not effectively used in the radical reaction includes the unreacted initiators not cleaved by radiation and those which become inactive by inhibition from the contact with objects to be reacted because of solid-phase reaction even though they become radical by cleavage.
Accordingly, the initiators are used in large quantities, so that large quantities of low molecular decomposition materials are generated at the time of light radiation and odor is emitted. Further, in the cured products after exposure, large quantities of residues derived from the initiators exist and among them, the un-self-cleaved photoradical initiators still keep reactivity even after the exposure and therefore denature the cured products. Also, the un-self-cleaved photoradical initiators and inactivated low molecular decomposition materials which are cleaved but not consumed by the radical reaction are not bonded to the crosslinking structure of the matrix and exist as independent components in the cured products to deteriorate the physical properties. Therefore, if the residues derived from the initiators are left as they are, they worsen the light fastness, colorization or discoloration, separation and cracking of the coating layers and lead to deterioration of the reliability of the final products, for example, interlayer insulating films for electronic parts, solder resist, resist for pixel formation for color filters.
The self-cleavage type photoradical initiator has a strong sublimation tendency and is decomposed by heat. It can be therefore removed from a product by post-baking after exposure and developing at a temperature higher than hundred and several tens degree. However, a large amount of a sublimated material originated from an initiator adheres to the inside of a heater and falls on a product obtained by curing during post-baking, causing product defects, posing a serious problem. Also, a decomposed material of an initiator or the like is involved in the atmosphere around the heater, posing a problem from the viewpoint of operational safety.
It is possible to remove more residues originated from a radical initiator by changing a post-baking condition to a condition of a higher-temperature and longer-operation time. However, it is difficult to remove the residues completely because of volatilization from a solid. If the condition is made stricter to remove many more impurities originated from a radical initiator, this condition rather causes product defects.
Secondary, use of resist for peeling films can be exemplified. Similarly to that of the above-mentioned solder resist, resist for processing electronic members, dry film resist or the like to be used for peeling films employ the photocuring system. The resists for processing are peeled and do not remain in the products finally, however, in the processing steps of copper wiring formation, the residues derived from the initiators from the resist films are eluted in chemical solutions such as ferric chloride, cupric chloride or the like to be used for the processing to shorten the chemical solution life.
Moreover, thirdly, use for coating material for protecting films can be exemplified. When a photosensitive resin is used as a wall used for buildings or paint for a protective layer protecting a surface of wall paper, there is a demand for decreasing solvent components or odorous components emitting from whole building material with the view of dealing with sick house syndrome. There is a problem that the use of a highly volatile initiator causes the occurrence of odors even after curing.
As one of the means for solving the above-mentioned problems, ESACURE KIP 150 (trade name) is commercialized by Nihon Siber Hegner K.K. The ESACURE KIP 150 has a structure in which photoradical generation portions are introduced in the side chains of the polymer skeleton. With such a structure, the photoradical generator has a plurality of radical generation portions in one molecule and therefore, if any one portion of the molecule is made radical and bonded with the matrix of the coating layer, the unreacted radical generation portions existing in the same molecule are bonded to the matrix structure and thus are not volatilized in post-baking and do not move in the coating layers to scarcely deteriorate the reliability of the final products.
However, ESACURE KIP 150 has a polymer skeleton with relatively large molecular size and therefore is difficult to move in a photosensitive resin composition. Further, the sensitive wavelength is not matched with the radiation wavelength of common light sources. Therefore, the sensitivity in the resin composition is not so high in practical use and the photoradical reactivity is hard to be increased.
As another solution, LUNA 750 (trade name) is commercialized by Nihon Siber Hegner K.K. The LUNA 750 is produced by introducing functional groups (side chains) with high molecular weight into self-cleavage type radical-generating parts having α-aminoacetophenone skeleton to increase the molecular weight of the parts to be isolated by cleavage at the time of radical generation and thus volatilization (outgas) of decomposition materials can be suppressed. However, in this case, the molecular weight in the cleaved parts is increased only to increase the temperature of the volatilization and make gasification difficult, the decomposition materials independent from the matrix structure of the coating layer remain in the coating layer. Therefore, it cannot sufficiently solve the problems of reliability deterioration, e.g. inferior products owing to the decomposition materials, occurrence of volatilization, elution, and odor emission of the decomposition materials, of the final products of coating layers or the like. Also, it cannot deal with the problem of elution of decomposition materials or unreacted materials derived from the initiators to developers or washing solutions in the case of development or washing intermediate products and final products.

Photo radical generator, photo sensitive resin composition and article


An engine unit with a decreased height dimension and longitudinal length comprises an engine and a throttle body assembly. The throttle body assembly includes front and rear throttle bodies formed with front and rear air cylinders and throttle valves. A fuel supply pipe is arranged between central axes of the air cylinders in a longitudinal direction to extend widthwise in a lower position than upper ends of the throttle bodies. A motor for driving throttle valves is arranged between the central axes of the air cylinders in the longitudinal direction. An axis of a rotating shaft of the motor is positioned forwardly or rearwardly of a central axis of the fuel supply pipe.

1. Field of the Invention
The present invention relates to an engine unit for a vehicle comprising a V-type engine and a throttle body assembly.
2. Description of Related Art
Various throttle body assemblies for V-type engines are conventionally known. For example, FIGS. 11 and 12 show a throttle body assembly 100 of a V-type engine as described in JP-A-2002-256900. As shown in FIG. 11, a motor 102 is arranged in a region surrounded by throttle bodies 103, 104 as viewed in plan view. Throttle valves 101 are driven by motor 102. As shown in FIG. 12, a front fuel supply pipe 105 and a rear fuel supply pipe 106 are arranged above motor 102 and between throttle bodies 103 and 104. Front fuel supply pipe 105 supplies fuel to a front injector 107 and rear fuel supply pipe 106 supplies fuel to a rear injector 108.
Because motor 102 and fuel supply pipes 105 and 106 are arranged between throttle bodies 103 and 104, throttle body assembly 100 can be decreased in magnitude as viewed in plan view. However, fuel supply pipes 105, 106 are aligned on throttle body assembly 100 in a longitudinal direction. Therefore, throttle bodies 103 and 104 must be arranged distantly from each other. Also, fuel supply pipes 105, 106 and motor 102 are aligned in a vertical direction. Since motor 102 vibrates due to engine vibrations, etc., some clearance between fuel supply pipes 105, 106 and motor 102 must be provided. Therefore, fuel supply pipes 105, 106 and motor 102 must be arranged away from each other. Accordingly, the height dimension of throttle body assembly 100 is increased. That is, with the construction shown in FIGS. 11 and 12, it is difficult to make the throttle body assembly sufficiently small in size. Accordingly, there is caused a problem in that it is difficult to make an engine unit, which includes the throttle body assembly, small in size.

Engine unit and vehicle provided with the same


Video game competition wagering in a hybrid game including a host game and a guest game is disclosed. A wager associated with a player in the host game is received. An outcome of at least one gambling event in the host game is determined. Game elements are associated with the player based at least in part on the gambling event outcome. The game elements may affect the player's interaction in a round of play of the guest game. A gaming outcome is determined based on the player's interaction with the round of play in the guest game.

In the casino gaming market, traditional slot machines are becoming less appealing to a new generation of consumers, who seek a more interactive, skill-based gaming experience. Virtual events have been used for gambling in casinos either via slot machines, kiosk terminal wagering, or at a track betting shop. They can be also found online in abundance. Traditionally, these virtual events are wholly non-interactive events. Individuals bet on virtual events by placing money directly into a slot machine, or as they would bet at a real life horse race where an individual walks up to a window and places a bet with a person or on a betting terminal. A random number generator determines either the outcome of a race, fight (or event subcomponent such as round of a fight, a quarter of a race, a period of a game), etc. For example in a horse race, a random number generator will determine the outcome based on either randomly selecting equally weighted horses (all have equal chance of winning) or randomly selecting probability weighted horses (where they have a probabilistic chance of winning).
In gaming (casino, horse betting, sports betting, etc.) virtual events are used for gambling either via a slot machine (kiosk or terminal wagering), or a monitor (simulcast TV screens at track or a betting shop). In a computer controlled simulation game, the combination of either play-by-play, punch-by-punch, or step-by-step complex algorithms, optimization models, decision trees, and probabilistic dice rolls are all utilized to determine how one competitor (or team) will behave and then independently how the different competitors or teams will respond.
The video game market is awash with multi-player interactive games ideally suited to quick competitive matches between individual or teams of players lasting short periods of time. Video games may be used in eSports. Typically, eSports involves teams of real players participating in a computer generated game by using interactive joysticks, and controllers, pads, etc. Games such as first person shooters ("FPS"), card games, fighting games and/or horse racing, all provide fast competitive matches with players competing as individuals or on teams to achieve some goal and to win the competition.
By contrast in eSports video games the in-game competitors are generally under player control, although "Bots" can be controlled by the simulation system when required. Wagering can be taken on eSports in the same way as virtual sports as eSports events. These events occur in an "environment" that has goals (scoring a touchdown, knocking out an opponent, winning a race), that has rules (where a competitor can hit, how much weight a horse must carry, etc.), constraints (the environmental constraints of a track, the physical constraints of not being able to run "through" other competitors), and the effects of other competitors (another player tackling you or forcing a fumble, another horse being in front of you and impeding your progress, being hit or bumped during a fight, game, or race, etc.). The outcome of a match depends on the actual completion of the event by the player competitors, and the outcome is determined once one or more competitors have successfully completed the event.
A multi-player video game may typically be structured in two parts: a server part which allows multiplayer play and a client part which allows individual player interaction with the game. A platform providing competitive wagering on video games would be desirable.

Systems and methods for video game competition wagering


An apparatus and method for improved control of low viscosity fluid flow during electrohydrodynamic spray deposition of the fluid to coat small targets, such as medical devices like stents. The apparatus includes a target holder which applies a first electrical potential to a target, a coating fluid transporter such as a wick, a siphon tube or a siphon tube with a wick therein along which the coating fluid flows from a reservoir to a dispensing end of the transporter, and an electrode which applied a second electrical potential to the coating fluid sufficient to cause the coating fluid to be attracted from the dispensing end of the transporter toward the target. This provides a target coating apparatus with highly self-regulating coating fluid flow characteristics despite the low viscosity of the coating fluid, while producing highly consistent and uniform target coatings.

Medical implants are used for innumerable medical purposes, including the reinforcement of recently re-enlarged lumens, the replacement of ruptured vessels, and the treatment of disease such as vascular disease by local pharmacotherapy, i.e., delivering therapeutic drug doses to target tissues while minimizing systemic side effects. Such localized delivery of therapeutic agents has been proposed or achieved using medical implants which both support a lumen within a patient's body and place appropriate coatings containing absorbable therapeutic agents at the implant location. Examples of such medical devices include catheters, guide wires, balloons, filters (e.g., vena cava filters), stents, stent grafts, vascular grafts, intraluminal paving systems, implants and other devices used in connection with drug-loaded polymer coatings. Such medical devices are implanted or otherwise utilized in body lumina and organs such as the coronary vasculature, esophagus, trachea, colon, biliary tract, urinary tract, prostate, brain, and the like.
The term "therapeutic agent" as used herein includes one or more "therapeutic agents" or "drugs". The terms "therapeutic agents" and "drugs" are used interchangeably herein and include pharmaceutically active compounds, nucleic acids with and without carrier vectors such as lipids, compacting agents (such as histones), virus (such as adenovirus, andenoassociated virus, retrovirus, lentivirus and α-virus), polymers, hyaluronic acid, proteins, cells and the like, with or without targeting sequences.
Specific examples of therapeutic agents used in conjunction with the present invention include, for example, pharmaceutically active compounds, proteins, cells, oligonucleotides, ribozymes, anti-sense oligonucleotides, DNA compacting agents, gene/vector systems (i.e., any vehicle that allows for the uptake and expression of nucleic acids), nucleic acids (including, for example, recombinant nucleic acids; naked DNA, cDNA, RNA; genomic DNA, cDNA or RNA in a non-infectious vector or in a viral vector and which further may have attached peptide targeting sequences; antisense nucleic acid (RNA or DNA); and DNA chimeras which include gene sequences and encoding for ferry proteins such as membrane translocating sequences ("MTS") and herpes simplex virus-1 ("VP22")), and viral, liposomes and cationic and anionic polymers and neutral polymers that are selected from a number of types depending on the desired application. Non-limiting examples of virus vectors or vectors derived from viral sources include adenoviral vectors, herpes simplex vectors, papilloma vectors, adeno-associated vectors, retroviral vectors, and the like. Non-limiting examples of biologically active solutes include anti-thrombogenic agents such as heparin, heparin derivatives, urokinase, and PPACK (dextrophenylalanine proline arginine chloromethylketone); antioxidants such as probucol and retinoic acid; angiogenic and anti-angiogenic agents and factors; anti-proliferative agents such as enoxaprin, angiopeptin, rapamycin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid; anti-inflammatory agents such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, acetyl salicylic acid, and mesalamine; calcium entry blockers such as verapamil, diltiazem and nifedipine; antineoplastic/antiproliferative/anti-mitotic agents such as paclitaxel, 5-fluorouracil, methotrexate, doxorubicin, daunorubicin, cyclosporine, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors; antimicrobials such as triclosan, cephalosporins, aminoglycosides, and nitorfurantoin; anesthetic agents such as lidocaine, bupivacaine, and ropivacaine; nitric oxide (NO) donors such as lisidomine, molsidomine, L-arginine, NO-protein adducts, NO-carbohydrate adducts, polymeric or oligomeric NO adducts; anti-coagulants such as D-Phe-Pro-Arg chloromethyl ketone, an RGD peptide-containing compound, heparin, antithrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, enoxaparin, hirudin, Warafin sodium, Dicumarol, aspirin, prostaglandin inhibitors, platelet inhibitors and tick antiplatelet factors; vascular cell growth promotors such as growth factors, growth factor receptor antagonists, transcriptional activators, and translational promotors; vascular cell growth inhibitors such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin; cholesterol-lowering agents; vasodilating agents; agents which interfere with endogeneus vascoactive mechanisms; survival genes which protect against cell death, such as anti-apoptotic Bcl-2 family factors and Akt kinase; and combinations thereof. Cells can be of human origin (autologous or allogenic) or from an animal source (xenogeneic), genetically engineered if desired to deliver proteins of interest at the insertion site. Any modifications are routinely made by one skilled in the art.
Polynucleotide sequences useful in practice of the invention include DNA or RNA sequences having a therapeutic effect after being taken up by a cell. Examples of therapeutic polynucleotides include anti-sense DNA and RNA; DNA coding for an anti-sense RNA; or DNA coding for tRNA or rRNA to replace defective or deficient endogenous molecules. The polynucleotides can also code for therapeutic proteins or polypeptides. A polypeptide is understood to be any translation product of a polynucleotide regardless of size, and whether glycosylated or not. Therapeutic proteins and polypeptides include as a primary example, those proteins or polypeptides that can compensate for defective or deficient species in an animal, or those that act through toxic effects to limit or remove harmful cells from the body. In addition, the polypeptides or proteins that can be injected, or whose DNA can be incorporated, include without limitation, angiogenic factors and other molecules competent to induce angiogenesis, including acidic and basic fibroblast growth factors, vascular endothelial growth factor, hif-1, epidermal growth factor, transforming growth factor α and β, platelet-derived endothelial growth factor, platelet-derived growth factor, tumor necrosis factor α, hepatocyte growth factor and insulin like growth factor; growth factors; cell cycle inhibitors including CDK inhibitors; anti-restenosis agents, including p15, p16, p18, p19, p21, p27, p53, p57, Rb, nFkB and E2F decoys, thymidine kinase ("TK") and combinations thereof and other agents useful for interfering with cell proliferation, including agents for treating malignancies; and combinations thereof. Still other useful factors, which can be provided as polypeptides or as DNA encoding these polypeptides, include monocyte chemoattractant protein ("MCP-1"), and the family of bone morphogenic proteins ("BMP's"). The known proteins include BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1), BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and BMP-16. Currently preferred BMP's are any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 and BMP-7. These dimeric proteins can be provided as homodimers, heterodimers, or combinations thereof, alone or together with other molecules. Alternatively or, in addition, molecules capable of inducing an upstream or downstream effect of a BMP can be provided. Such molecules include any of the "hedgehog" proteins, or the DNA's encoding them.
Coatings used with the present invention may comprise a polymeric material/drug agent matrix formed, for example, by admixing a drug agent with a liquid polymer, in the absence of a solvent, to form a liquid polymer/drug agent mixture. Curing of the mixture typically occurs in-situ. To facilitate curing, a cross-linking or curing agent may be added to the mixture prior to application thereof. Addition of the cross-linking or curing agent to the polymer/drug agent liquid mixture must not occur too far in advance of the application of the mixture in order to avoid over-curing of the mixture prior to application thereof. Curing may also occur in-situ by exposing the polymer/drug agent mixture, after application to the luminal surface, to radiation such as ultraviolet radiation or laser light, heat, or by contact with metabolic fluids such as water at the site where the mixture has been applied to the luminal surface. In coating systems employed in conjunction with the present invention, the polymeric material may be either bioabsorbable or biostable. Any of the polymers described herein that may be formulated as a liquid may be used to form the polymer/drug agent mixture.
In a preferred embodiment, the polymer used to coat the medical device is provided in the form of a coating on an expandable portion of a medical device. After applying the drug solution to the polymer and evaporating the volatile solvent from the polymer, the medical device is inserted into a body lumen where it is positioned to a target location. In the case of a balloon catheter, the expandable portion of the catheter is subsequently expanded to bring the drug-impregnated polymer coating into contact with the lumen wall. The drug is released from the polymer as it slowly dissolves into the aqueous bodily fluids and diffuses out of the polymer. This enables administration of the drug to be site-specific, limiting the exposure of the rest of the body to the drug.
The polymer used in the present invention is preferably capable of absorbing a substantial amount of drug solution. When applied as a coating on a medical device in accordance with the present invention, the dry polymer is typically on the order of from about 1 to about 50 microns thick. In the case of a balloon catheter, the thickness is preferably about 1 to 10 microns thick, and more preferably about 2 to 5 microns. Very thin polymer coatings, e.g., of about 0.2-0.3 microns and much thicker coatings, e.g., more than 10 microns, are also possible. It is also within the scope of the present invention to apply multiple layers of polymer coating onto a medical device. Such multiple layers are of the same or different polymer materials.
The polymer of the present invention may be hydrophilic or hydrophobic, and may be selected from the group consisting of polycarboxylic acids, cellulosic polymers, including cellulose acetate and cellulose nitrate, gelatin, polyvinylpyrrolidone, cross-linked polyvinylpyrrolidone, polyanhydrides including maleic anhydride polymers, polyamides, polyvinyl alcohols, copolymers of vinyl monomers such as EVA, polyvinyl ethers, polyvinyl aromatics, polyethylene oxides, glycosaminoglycans, polysaccharides, polyesters including polyethylene terephthalate, polyacrylamides, polyethers, polyether sulfone, polycarbonate, polyalkylenes including polypropylene, polyethylene and high molecular weight polyethylene, halogenated polyalkylenes including polytetrafluoroethylene, polyurethanes, polyorthoesters, proteins, polypeptides, silicones, siloxane polymers, polylactic acid, polyglycolic acid, polycaprolactone, polyhydroxybutyrate valerate and blends and copolymers thereof as well as other biodegradable, bioabsorbable and biostable polymers and copolymers. Coatings from polymer dispersions such as polyurethane dispersions (BAYHDROL®, etc.) and acrylic latex dispersions are also within the scope of the present invention. The polymer may be a protein polymer, fibrin, collage and derivatives thereof, polysaccharides such as celluloses, starches, dextrans, alginates and derivatives of these polysaccharides, an extracellular matrix component, hyaluronic acid, or another biologic agent or a suitable mixture of any of these, for example. In one embodiment of the invention, the preferred polymer is polyacrylic acid, available as HYDROPLUS® (Boston Scientific Corporation, Natick, Mass.), and described in U.S. Pat. No. 5,091,205, the disclosure of which is hereby incorporated herein by reference. U.S. Pat. No. 5,091,205 describes medical devices coated with one or more polyisocyanates such that the devices become instantly lubricious when exposed to body fluids. In another preferred embodiment of the invention, the polymer is a copolymer of polylactic acid and polycaprolactone.
The delivery of expandable stents is a specific example of a medical procedure that may involve the deployment of coated implants. Expandable stents are tube-like medical devices, typically made from stainless steel, Tantalum, Platinum or Nitinol alloys, designed to be placed within the inner walls of a lumen within the body of a patient. These stents are typically maneuvered to a desired location within a lumen of the patient's body and then expanded to provide internal support for the lumen. The stents may be self-expanding or, alternatively, may require external forces to expand them, such as by inflating a balloon attached to the distal end of the stent delivery catheter.
Where a stent or other medical device is to be coated, care must be taken during its manufacture to ensure the coating is properly applied and firmly adherent. When the amount of coating is insufficient or is depleted through stripping of poorly adherent coating during manufacture or deployment within the patient's body, the device's effectiveness may be compromised and additional risks may be inured into the procedure. For example, when the coating of the device includes a therapeutic, if some of the coating were removed during deployment, the therapeutic may no longer be able to be administered to the target site in a uniform and homogenous manner. Thus, some areas of the target site may receive high quantities of therapeutic while others may receive low quantities of therapeutic. Similarly, if the therapeutic is ripped from the device it can reduce or slow down the blood flowing past it, thereby increasing the threat of thrombosis or, if it becomes dislodged, the risk of embolisms. In certain circumstances, the removal and reinsertion of the device through a second medical procedure may be required where the coatings have been damaged or are defective.
The mechanical process of applying a coating onto a stent or other medical device may be accomplished in a variety of ways, including, for example, spraying the coating substance onto the device, so-called spin-dipping, i.e., dipping a spinning device into a coating solution to achieve the desired coating, and electrohydrodynamic fluid deposition, i.e., applying an electrical potential difference between a coating fluid and a target to cause the coating fluid to be discharged from the dispensing point and drawn toward the target.
Common to these processes is the need to apply the coating in a manner to ensure that an intact, robust coating of the desired thickness is formed on the stent. Obtaining a uniform coating often becomes difficult when working with coating fluids with low viscosities. In the case of electrohydrodynamic coating, when viscosity drops to a low viscosity, for example in the vicinity of one centipoise, it is difficult to control how much coating fluid is exposed to the electrohydrodynamic conditions. Non-uniform coating application is also a problem at very low coating fluid flow rates, where difficulty controlling conventional pumping means can result in erratic fluid flow from the coating dispenser. Lack of uniformity can be a problem as well where the coating fluid flow is applied to individual target work pieces in a start-stop fashion if the low viscosity coating fluid is given enough time to retreat from the coating fluid discharge point.
Further, obtaining a coating of the desired thickness requires precise coordination of the operating elements of the coating dispensing apparatus. In the case, for example, of an electrohydrodynamic coating system that employs a positive displacement pump to power the coating fluid dispenser, the electrohydrodynamic conditions must be closely matched to the pump in order to consistently achieve the desired uniform target coating. For example, if the electrohydrodynamic impulse is not applied as quickly as the pump is able to supply coating fluid to the dispensing head, excess fluid drops may form on the dispensing head and randomly alter the coating fluid deposition rate and spray pattern. Conversely, if the electrohydrodynamic impulse is faster than the pump can deliver coating fluid to the dispensing head, insufficient coating may result when the amount of coating material at the dispensing head is depleted by the electrohydrodynamic pulse before the pump can supply an adequate volume of additional coating fluid to the dispensing head. Under these conditions, it is difficult to achieve and sustain the required pump and electrohydrodynamic impulse coordination over the course of stent coating production runs.
Thus, there is a need for an apparatus and method for electrohydrodynamically applying a low viscosity coating fluid to a target such as a stent in a manner that results in a high quality coating of desired thickness, and preferably accomplishes this objective at high production rates.

Electrohydrodynamic coating fluid delivery apparatus and method


A high quality wafer comprising AlxGayInzN, wherein 0 less than yxe2x89xa61 and x+y+z=1, characterized by a root mean square surface roughness of less than 1 nm in a 10xc3x9710 xcexcm2 area at its Ga-side. Such wafer is chemically mechanically polished (CMP) at its Ga-side, using a CMP slurry comprising abrasive particles, such as silica or alumina, and an acid or a base. The process of fabricating such high quality AlxGayInzN wafer may include steps of lapping, mechanical polishing, and reducing internal stress of said wafer by thermal annealing or chemical etching for further enhancement of its surface quality. The CMP process is usefully employed to highlight crystal defects on the Ga-side of the AlxGayInzN wafer.

I. Field of the Invention
This invention relates to an AlxGayInzN (wherein 0 less than yxe2x89xa61 and x+y+z=1) semiconductor wafer having superior surface quality at its Ga-side, and to a method of fabricating such E wafer.
II. Description of the Related Art
GaN and related GaN-like III-V nitride crystal films, represented by the general formula AlxGayInzN, wherein 0 less than yxe2x89xa61 and x+y+z=1, are useful materials in various applications, such as high temperature electronics, power electronics, and optoelectronics (e.g., light emitting diodes (LEDs) and blue light laser diodes (LDs)). Blue light emitting diodes (LED""s) and lasers are an enabling technology, allowing much higher storage density in magneto-optic memories and CDROM""s and the construction of full color light emitting displays. Blue light emitting diodes may replace today""s incandescent light bulbs in road and railway signals etc., where they promise very substantial cost and energy savings.
Currently, AlxGayInzN films are grown on non-native substrates such as sapphire or silicon carbide due to unavailability of high quality AlxGayInzN substrates. However, differences in thermal expansion and lattice constants between such foreign substrates and the AlxGayInzN crystals epitaxially grown thereon cause significant thermal stress and internal stress in the grown AlxGayInzN crystals. The thermal stress and internal stress cause micro-cracks, distortions, and other defects in the AlxGayInzN crystals, and make such AlxGayInzN crystals easy to break. Growing on lattice non-matched foreign substrates causes high density of lattice defects, leading to poor device performance.
In order to reduce the deleterious thermal stress and high defect density in the grown AlxGayInzN crystals, it is desirable to provide high quality freestanding AlxGayInzN wafers as film-growing substrates in place of the above-mentioned foreign substrates.
U.S. Pat. No. 5,679,152 entitled xe2x80x9cMethod for Making a Single Crystal Ga*N Articlexe2x80x9d and U.S. Pat. No. 5,679,153 entitled xe2x80x9cBulk Single Crystal Gallium Nitride and Method of Making Samexe2x80x9d disclose a hydride vapor phase epitaxy (HVPE) process for fabricating freestanding AlxGayInzN crystals, which may advantageously be used as crystal-growing substrates for homoepitaxial growth of AlxGayInzN crystals thereon.
Since quality of a subsequently grown AlxGayInzN crystal is directly correlated to the quality of the substrate surface and near surface region on which the AlxGayInzN crystal is grown, it is important to provide a highly smooth initial substrate surface without any surface and subsurface damage.
However, after mechanical polishing, the AlxGayInzN crystals typically have very poor surface quality, with substantial surface and subsurface damage and polishing scratches. Additional wafer finish processing therefore is necessary to further enhance the surface quality of the freestanding AlxGayInzN crystal, so that it is suitable for high-quality epitaxial growth and device fabrication thereon.
Crystalline AlxGayInzN generally exists in a chemically stable wurtzite structure. The most common crystallographic orientation of AlxGayInzN compounds has two polar surfaces perpendicular to its c-axis: one side is N-terminated, and the other one is Ga-terminated (Ga hereinafter in the context of the Ga-side of the crystal structure being understood as generally illustrative and representative of alternative Group III (AlxGayInz) crystalline compositions, e.g., of a corresponding GaxIny-side in GaxInyN crystals, of a corresponding AlxGayInz-side in AlxGayInzN crystals, and of a corresponding AlxGay-side in AlxGayN crystals).
Crystal polarity strongly influences the growth morphology and chemical stability of the crystal surface. It has been determined that the N-side of the AlxGayInzN crystal is chemically reactive with KOH or NaOH-based solutions, whereas the Ga-side of such crystal is very stable and not reactive with most conventional chemical etchants. The N-side can therefore be easily polished, using an aqueous solution of KOH or NaOH, to remove surface damage and scratches left by the mechanical polishing process and to obtain a highly smooth surface.
The Ga-side (AlxGayInz side) of the AlxGayInzN crystal, on the other hand, remains substantially the same after contacting the KOH or NaOH solution, with its surface damage and scratches unaltered by such solution. See Weyher et al., xe2x80x9cChemical Polishing of Bulk and Epitaxial GaNxe2x80x9d, J. CRYSTAL GROWTH, vol. 182, pp. 17-22, 1997; also see Porowski et al. International Patent Application Publication No. WO 98/45511 entitled xe2x80x9cMechano-Chemical Polishing of Crystals and Epitaxial Layers of GaN and Ga1xe2x88x92xxe2x88x92yAlxInyNxe2x80x9d.
However, it has been determined that the Ga-side of the AlxGayInzN crystal is a better film-growing surface than the N-side. See Miskys et al., xe2x80x9cMOCVD-Epitaxy on Free-Standing HVPE-GaN Substratesxe2x80x9d, PHYS. STAT. SOL. (A), vol. 176, pp. 443-46, 1999. It therefore is important to provide a wafer finish process that is particularly effective for preparing the Ga-side of the AlxGayInzN crystal to make it suitable for subsequent crystal growth thereupon.
Reactive ion etching (RIE) recently has been used to remove a layer of surface material from the Ga-side of an AlxGayInzN wafer to obtain smoother wafer surface. See Karouta et al., xe2x80x9cFinal Polishing of Ga-Polar GaN Substrates Using Reactive Ion Etchingxe2x80x9d, J. ELECTRONIC MATERIALS, vol. 28, pp. 1448-51, 1999. However, such RIE process is unsatisfactory because it is ineffective for removing deeper scratches, and it introduces additional damage by ion bombardment and additional surface irregularities by concomitant contamination, which in turn requires additional cleaning of the GaN wafer in an O2 plasma.
It is therefore advantageous to provide an AlxGayInzN wafer with high surface quality on its Ga-side, with substantially no or little surface and subsurface damage or contamination. It is also desirable that such AlxGayInzN wafer is prepared by a surface polishing process that is both economic and effective, and requires no cumbersome cleaning process during or after polishing.
The present invention generally relates to an AlxGayInzN (wherein 0 less than yxe2x89xa61 and x+y+z=1) wafer having superior surface quality at its Ga-side, and to a method of fabricating such wafer.
One aspect of the present invention relates to a high quality AlxGayInzN wafer of such type, wherein the wafer has a surface roughness characterized by a root means square (RMS) roughness of less than 1 nm in a 10xc3x9710 xcexcm2 area at its Ga-side.
In ranges of progressively increasing preference, the RMS surface roughness of such wafer at its Ga-side is within the following ranges: (1) less than 0.7 nm in a 10xc3x9710 xcexcm2 area; (2) less than 0.5 nm in a 10xc3x9710 xcexcm2 area; (3) less than 0.4 nm in a 2xc3x972 xcexcm2 area; (4) less than 0.2 nm in a 2xc3x972 xcexcm2 area; and (5) less than 0.15 nm in a 2xc3x972 xcexcm2 area.
AIxGayInzN wafers according to the present invention preferably are characterized by a regular step structure at the Ga-side thereof when observed by atomic force microscope.
AlxGayInzN wafers according to the present invention preferably are characterized by that the crystal defects of the AlxGayInzN wafer at its Ga-side constitute small pits with diameters of less than 1 xcexcm. Small pits of such size are readily visible by both atomic force microscope (AFM) and scanning electron microscope (SEM) techniques, while at the same time these pits do not constitute significant damage of the AlxGayInzN wafer surface and therefore do not impair quality of AlxGayInzN crystals subsequently grown thereon.
Such high quality AlxGayInzN crystal wafers are readily manufactured by chemically mechanically polishing (CMP) AlxGayInzN wafer blanks at the Ga-side thereof, using silica or alumina-containing CMP slurry compositions. The corresponding CMP process enables the crystal defects of the AlxGayInzN wafer (evidenced by small pits of less than 1 xcexcm in diameter) to be readily visualized.
Another aspect of the present invention relates to an epitaxial AlxGayInzN crystal structure, comprising an epitaxial Alxxe2x80x2Gayxe2x80x2Inzxe2x80x2N (wherein 0 less than yxe2x80x2xe2x89xa61 and xxe2x80x2+yxe2x80x2+zxe2x80x2=1) film grown on the above-described AlxGayInzN wafer of the invention. Such epitaxial AlxGayInzN crystal structure preferably comprises a wurtzite crystalline thin film, but may be in any other suitable form or structure suitable for specific semiconductor, electronic, or optoelectronic applications. The composition of the epitaxial film may be or may not be the same as the composition of the wafer substrate. The epitaxial AlxGayInzN crystal structure may comprise several epitaxial Alxxe2x80x2Gayxe2x80x2Inzxe2x80x2N films with different composition or doping sequentially grown on the above-described AlxGayInzN wafer of the invention. The epitaxial film may have graded composition, i.e., the composition of the epitaxial film varies with the distance from the interface between the substrate and epitaxial film. As used herein,. the term xe2x80x9cthin filmxe2x80x9d means a material layer having a thickness of less than about 100 xcexcm.
Yet another aspect of the present invention relates to an optoelectronic device that comprises at least one such epitaxial AlxGayInzN crystal structure grown on the above-described AlxGayInzN wafer of the invention.
A further aspect of the present invention relates to a microelectronic device that comprises at least one such epitaxial AlxGayInzN crystal structure grown on the above-described AlxGayInzN wafer of the invention.
A further aspect of the present invention relates to an AlxGayInzN boule that comprises epitaxial AlxGayInzN crystal structure grown on the above-described AlxGayInzN wafer of the invention. A boule is defined as that it can be sliced into at least two wafers. An AlxGayInzN boule can be grown with any suitable method such as hydride vapor phase epitaxy (HVPE), the metallorganic chloride (MOC) method, metallorganic chemical vapor deposition (MOCVD), sublimation, liquid phase growth, etc.
The invention in a further aspect contemplates a method of chemically mechanically polishing (CMP) an AlxGayInzN wafer at its Ga-side, using a CMP slurry comprising:
Abrasive amorphous silica particles having particle size of less than 200 nm;
at least one acid; and
optionally, at least one oxidation agent;
wherein the pH value of the CMP slurry is in a range of from about 0.5 to about 4.
The abrasive amorphous silica particles in the CMP slurry may for example comprise fumed silica or colloidal silica. The amorphous silica particles in the CMP slurry preferably have an average particle size in the range from about 10 nm to about 100 nm. The CMP slurry of the invention in a preferred compositional aspect comprises at least one oxidation agent, e.g., hydrogen peroxide, dichloroisocyanuric acid, or the like.
The pH value of such CMP slurry preferably is in a range of from about 0.6 to about 3, and more preferably is in a range of from about 0.8 to about 2.5.
A further aspect of the present invention relates to a method of chemically mechanically polishing (CMP) an AlxGayInzN wafer at its Ga-side, using a CMP slurry comprising:
abrasive colloidal alumina particles having particle size of less than 200 nm;
at least one acid; and
optionally, at least one oxidation agent;
wherein the pH value of the CMP slurry is in a range of from about 3 to about 5.
The abrasive colloidal alumina particles in the CMP slurry preferably have particle sizes in a range from about 10 nm to about 100 nm.
The CMP slurry of the invention in a preferred compositional aspect comprises at least one oxidation agent, e.g., hydrogen peroxide, dichloroisocyanuric acid, or the like.
The pH value of such CMP slurry preferably is in a range of from about 3 to about 4.
A further aspect of the present invention relates to chemical mechanical polishing (CMP) of the AlxGayInzN wafer at its Ga-side, using a CMP slurry that comprises:
amorphous silica particles having particle sizes of less than 200 nm;
at least one base; and
optionally, at least one oxidation agent,
wherein the pH value of the CMP slurry is in a range from about 8 to about 13.5.
The amorphous silica particles in such CMP slurry preferably comprise fumed silica particles having particle sizes in the range from about 10 nm to about 100 nm, or colloidal silica particles having particle sizes in the range from about 10 nm to about 100 nm.
Bases useful for the practice of the present invention include, but are not limited to, ammonia, alkanolamines, and hydroxides, e.g., KOH or NaOH. Ammonia and alkanolamines are particularly preferred, since they also function to stabilize the CMP slurry.
Such CMP slurry comprises at least one oxidation agent, e.g., hydrogen peroxide, dichloroisocyanuric acid or the like.
The pH value of such CMP slurry preferably is in a range of from about 9 to about 13, and more preferably the pH is in a range of from about 10 to about 11.
A further aspect of the present invention relates to a method of highlighting crystal defects of an AlxGayInzN wafer at it Ga-side to facilitate determination of crystal defect density of such wafer, comprising the steps of:
providing an AlxGayInzN wafer;
chemically mechanically polishing the wafer at its Ga-side, according to one of the above-described CMP methods of the invention;
cleaning and drying the polished AlxGayInzN wafer; and
scanning the wafer with an atomic force microscope or a scanning electron microscope to determine defect density in the wafer.
The CMP process is preferably conducted using an acidic silica slurry as described hereinabove.
Yet another aspect of the present invention relates to a method of fabricating high quality AlxGayInzN wafers, comprising the steps of:
providing an AlxGayInzN wafer blank having thickness in a range of from about 100 xcexcm to about 1000 xcexcm;
optionally reducing internal stresses of the AlxGayInzN wafer;
optionally lapping the AlxGayInzN wafer blank at its N-side, using a lapping slurry comprising abrasives having an average particle size in a range of from about 5 xcexcm to about 15 xcexcm;
optionally mechanically polishing the AlxGayInzN wafer blank at its N-side, using a mechanical polishing slurry comprising abrasives having average particle size in a range of from about 0.1 xcexcm to about 6 xcexcm;
optionally lapping the AlxGayInzN wafer blank at its Ga-side, using a lapping slurry comprising abrasives having an average particle size in a range of from about 5 xcexcm to about 15 xcexcm;
mechanically polishing the AlxGayInzN wafer blank at its Ga-side, using a mechanical polishing slurry comprising abrasives having average particle size in a range of from about 0.1 xcexcm to about 6 xcexcm;
chemically mechanically polishing the AlxGayInzN wafer at its Ga-side, using a CMP slurry comprising at least one chemical reactant and abrasive colloidal particles having average particle size of less than 200 nm; and
optionally mild etching to further reduce internal stresses of the AlxGayInzN wafer and. improve the surface quality,
wherein the resultant AlxGayInzN wafer has a root mean square (RMS) surface roughness of less than 1 nm in a 10xc3x9710 xcexcm2 area at its Ga-side.
The AlxGayInzN wafer blank may be produced by any suitable method, as for example: (1) growing an AlxGayInzN boule and then slicing it into wafer blanks; or (2) growing a thick AlxGayInzN film on a foreign substrate and then separating such thick film from the substrate. The wafer blank may be oriented so that the c-axis is perpendicular to the wafer surface or it may be intentionally slightly misoriented (c-axis not perpendicular to the wafer surface) to facilitate subsequent epitaxy growth, device processing or device design.
The AlxGayInzN wafer blank may be subjected to processing for reducing the internal stress caused, for example, by the disparity of thermal coefficients and lattice constants between such AlxGayInzN wafer and the foreign substrate on which it is grown. Reduction of internal stress may be conducted either by thermally annealing the AlxGayInzN wafer or chemically etching the wafer.
Thermal annealing preferably is carried out at an elevated temperature, e.g., from about 700xc2x0 C. to about 1000xc2x0 C., in nitrogen or ammonia environment for a time of from about 1 minute to about 1 hour.
Chemical etching of the AlxGayInzN wafer functions to remove a layer of surface material from said wafer, thereby relaxing the internal stress of said wafer. It is preferred that the chemical etching process effect a removal of surface material of less than 100 xcexcm in thickness of said wafer, and more preferably less than 10 xcexcm thickness.
The AlxGayInzN wafer can be chemically etched either by a very strong acid at elevated temperatures, e.g., sulfuric acid, phosphoric acid, or combinations thereof, or by a very strong base at elevated temperatures, e.g., molten KOH or NaOH.
Lapping slurry compositions advantageously used in the practice of the present invention may comprise any suitable abrasives, including, but not limited to, diamond powders, silicon carbide powders, boron carbide powders, and alumina powders. Preferably, the lapping slurry comprises diamond powder having average particle size in the range from about 6 xcexcm to about 10 xcexcm. More preferably, two or more lapping slurries lap the AlxGayInzN wafer blank, with each subsequent lapping slurry comprising abrasives of a progressively smaller average size. For example, the AlxGayInzN wafer blank may be lapped by a first slurry comprising abrasives of an average size from about 8 xcexcm to about 10 xcexcm, and then by a second slurry comprising abrasives of an average size from about 5 xcexcm to about 7 xcexcm.
Similarly, the mechanical polishing slurry useful in the present invention may comprise any suitable abrasives, including but not limited to diamond powders, silicon carbide powders, boron carbide powders, and alumina powders. Diamond powders with average particle size in the range from about 0.1 xcexcm to about 3 xcexcm are particularly preferred. The mechanical polishing step may also employ two or more mechanical polishing slurries, with each subsequent mechanical polishing slurry comprising abrasives of a progressively smaller particle size. For example, a first mechanical polishing slurry comprising abrasives of an average size from about 2.5 xcexcm to about 3.5 xcexcm can be used, followed by a second mechanical polishing slurry comprising abrasives of an average size from about 0.75 xcexcm to about 1.25 xcexcm, followed by a third mechanical polishing slurry comprising abrasives of an average size from about 0.35 xcexcm to about 0.65 xcexcm, followed by a fourth mechanical polishing slurry comprising abrasives of an average size from about 0.2 xcexcm to about 0.3 xcexcm, and finally by a fifth mechanical polishing slurry comprising abrasives of an average size from about 0.1 xcexcm to about 0.2 xcexcm.
The CMP slurry comprises at least one chemical reactant, which can be either an acid or a base. When it is an acid, it is preferable to adjust the pH value of the CMP slurry to a value in a range of about 0.5 to about 4; if it is instead a base, it is preferable to adjust the pH value of such slurry to a value in a range of from about 8 to about 13.5.
After the CMP, the AlxGayInzN wafer may be subjected to additional processing for further reducing the stress of the wafer and improving the surface quality. A mild etching is preferred for this purpose. The mild etching may remove some residual surface damage on the Ga-side surface from final CMP polishing while not etch the undamaged surface of Ga-side, thus improve the surface quality. The mild etching can also remove the damage on the N-side surface, thus reduce the stress on the wafer caused by surface damage. This mild etching can also produce a mat finish on the N-side surface. For example, the wafer can be slightly etched in an aqueous solution of base (for example, KOH or NaOH) or an aqueous solution of acid (for example, HF, H2SO4, or H3PO4) at a temperature below the boiling point of the aqueous solution, typically about 100xc2x0 C.
Other aspects, features, and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.

High surface quality GaN wafer and method of fabricating same


A nonvolatile memory element of the present invention comprises a first electrode (103), a second electrode (105), and a resistance variable layer (104) disposed between the first electrode (103) and the second electrode (104), a resistance value of the resistance variable layer varying reversibly according to an electric signal applied between the electrodes (103), (105), and the resistance variable layer (104) comprises at least a tantalum oxide, and is configured to satisfy 0<x<2.5 when the tantalum oxide is represented by TaOx.

With recent advancement of digital technologies, higher functionality of electronic hardware such as portable information devices and home information appliances have been provided. For this reason, demands for an increase in a capacity of a nonvolatile memory element, a reduction in writing electric power in the memory element, a reduction in write/readout time in the memory element, and longer life of the memory element have been increasing.
In response to such demands, it is said that there is a limitation on miniaturization of an existing flash memory using a floating gate. On the other hand, a nonvolatile memory element (resistance variable memory) using a resistance variable layer as a material of a memory portion is formed by a memory element having a simple structure including a resistance variable element. Therefore, further minitualization, a higher-speed, and further electric power saving of the nonvolatile memory element are expected.
When using the resistance variable layer as the material of the memory portion, its resistance value varies from a high-resistance value to a low-resistance value or from the low-resistance value to the high-resistance value, for example, by inputting electric pulses. In this case, it is necessary to clearly distinguish two values, i.e., the high-resistance value and the low-resistance value, to vary the resistance value stably between the low-resistance value and the high-resistance value at a high-speed, and to hold these two values in a nonvolatile manner. For the purpose of stabilization of such a memory property and minitualization of memory elements, a variety of proposals have been proposed in the past.
As one of such proposals, patent document 1 discloses a memory element in which memory cells are formed by resistance variable elements each of which includes two electrodes and a storing layer sandwiched between these electrodes and is configured to reversibly vary a resistance value of the storing layer. FIG. 33 is a cross-sectional view showing a configuration of such a conventional memory element.
As shown in FIG. 33, the memory element has a configuration in which a plurality of resistance variable elements 10 forming memory cells are arranged in array. The resistance variable element 10 has a configuration in which a high-resistance film 2 and an ion source layer 3 are sandwiched between a lower electrode 1 and an upper electrode 4. The high-resistance film 2 and the ion source layer 3 form a storing layer. The storing layer enables data to be stored in the resistance variable element 10 in each memory cell.
The resistance variable elements 10 are disposed above MOS transistors 18 formed on a semiconductor substrate 11. The MOS transistor 18 includes source/drain regions 13 formed in a region separated by an isolation layer 12 inside the semiconductor substrate 11 and a gate electrode 14. The gate electrode 14 also serves as a word line which is one address wire of the memory element.
One of the source/drain regions 13 of the MOS transistor 18 is electrically connected to the lower electrode 1 of the resistance variable element 10 via a plug layer 15, a metal wire layer 16, and a plug layer 17. The other of the source/drain regions 13 of the MOS transistor 18 is connected to the metal wire layer 16 via the plug layer 15. The metal wire layer 16 is connected to a bit line which is the other address wire of the memory element.
By applying electric potentials of different polarities between the lower electrode 1 and the upper electrode 4 of the resistance variable element 10 configured as described above, ion source of the ion source layer 3 forming the storing layer is caused to migrate to the high-resistance layer 2. Or, the ion source is caused to migrate from the high-resistance layer 2 to the upper electrode 4. Thereby, the resistance value of the resistance variable element 10 transitions from a value of a high-resistance state to a value of a low-resistance state, or from a value of the low-resistance state to a value of the high-resistance state, so that data is stored.
A memory element (phase-change type memory) is also known, in which a resistance variable material sandwiched between an upper electrode and a lower electrode forms a first electric pulse varying resistance layer having a polycrystalline structure and a second electric pulse varying resistance layer having a nano crystal or an amorphous structure. The resistance layer formed of the resistance variable material is controlled by varying its resistance value according to a voltage and a pulse width of electric pulses applied, thereby operating as a resistance variable element (see, for example, patent document 2).
Examples using transition metal oxide consisting of two elements, which are different from the resistance variable materials disclosed in Patent documents 1 and 2, are reported. For example, Patent document 3 discloses as the resistance variable material, NiO, V2O5, ZnO, Nb2O5, TiO2, WO3, and CoO. These materials consist of two elements and therefore, composition control therefor and film forming using them are relatively easy. In addition, these materials may have relatively high affinity with a semiconductor manufacturing process.
Patent document 4 discloses a variety of resistance variable materials obtained by the fact that a p-type oxide semiconductor material comprising metal elements has rapid metal-insulator transfer. In particular, specific examples thereof are Ga, As and VO2. Patent document 5 discloses, as examples of a resistance variable material, titanium oxide and Ta2O5 which is tantalum oxide as insulators whose resistance states change, respectively.    Patent document 1: Japanese Laid-Open Patent Application Publication No. 2006-40946    Patent document 2: Japanese Laid-Open Patent Application Publication No. 2004-349689    Patent document 3: Japanese Laid-Open Patent Application Publication No. 2004-363604    Patent document 4: Japanese Laid-Open Patent Application Publication No. 2006-32898    Patent document 5: Japanese Laid-Open Patent Application Publication No. Hei. 7-263647    Non-patent document 1: I. G. Beak Et Al., Tech. Digest IEDM 204, 587 page    Non-patent document 2: Japanese Journal of Applied Physics Vol 145, NO 11, 2006, pp. L3 10-L312 FIG. 2

Nonvolatile memory element, nonvolatile memory apparatus, nonvolatile semiconductor apparatus, and method of manufacturing nonvolatile memory element

PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.


A method for creating brightness filters. The brightness filters are used in a projection system in which divided images are projected on a curved screen from a plurality of projectors with adjacent divided images overlapped partially, in order to adjust brightness of the divided images beforehand so that brightness of overlapping areas between the divided images is in harmony with brightness of non-over-lapping areas. The feature of the present invention resides in that the method includes a step of allocating one of the divided images to a reference image and allocating each of the adjacent divided images to a peripheral image, setting a view point that is coincident with the projection point of the reference image, and obtaining a 2-dimensional reference area of the reference image that is rendered on the screen model and is viewed from the view point.

Japanese Non-examined Patent Publication No. 2002-148711 discloses a virtual space creation system. This virtual space creation system is intended to immerse an observer in a virtual space with the use of a curved screen giving a wide field of view for image projection.
In order to give immersion to several observers at the same time, a large screen is needed. Japanese Non-examined Patent Publication No. 2001-306024 discloses a system for projecting images on a large screen. In this invention, the system divides a single seamless image into a plurality of divided images, and projects the divided images on a large flat screen from a plurality of projectors. Each of the divided images is projected on the flat screen with adjacent ones of the divided images partially overlapped so as not to produce a clearance between the divided images. Since overlapping areas which overlap between the adjacent divided images have high-brightness, the overlapping areas appear to be bright on the screen. To solve this program, a brightness filter is used. The brightness filter lowers the brightness of the overlapping areas of each of the divided images according to an overlapping amount between divided images. Each of the divided images is projected on the flat screen after the brightness of its overlapping area is lowered by the brightness filter. In this way, this system can obtain a seamless combined image in which the brightness of the overlapping areas is in harmony with the brightness of non-overlapping areas.
In above-mentioned invention, because of a flat screen, the images are projected on the flat screen without being distorted. Therefore, it is easy to calculate overlapping areas of divided images and create brightness filters beforehand, if a positional relationship between the projector and the screen, a shape of the image projected from the projector, etc. are known.
However, if the screen is a curved screen, it is very difficult to calculate overlapping areas of each of the divided images and create brightness filters beforehand, because each of the divided images on the screen is distorted.

Method for creating brightness filter and virtual space creation system


Construction and method of making a decorative cracked glass laminate in tile, panel, sheet, plate, veneer or in situ form. It comprises three layers laminated together, an inner backing layer, a substantially light-transparent outer layer, and a decoratively cracked glass intermediate layer sandwiched between the inner and outer layers. The intermediate layer, preferably a mirror, is made of tempered glass and the outer layer is made of annealed glass. The laminate is made by laminating the inner and outer layers to the intermediate layer while it is in uncracked condition, and then causing it to crack in situ as by cutting into an exposed edge. Alternatively, the two glass layers may be laminated together and then laid in a backing material such as plastics which then forms the backing layer of the two-glass laminate.

Mirrored ceiling and wall surfaces are decoratively appealing, but prior to my U.S. Pat. No. 4,990,407 they presented structural and construction problems. As noted in that patent, if the mirror is to be glass, as is generally preferred, weight is a significant disadvantage, particularly in ceilings where it is difficult to handle large glass panels during installation and difficult to provide adequate structural support. Smaller glass mirrors, in the form or size of tiles, reduce the weight problem of each individual piece, but at least two significant problems remain. First, glass mirrors are not good acoustical absorbers, and therefore yield higher than necessary sound levels where used. Second, glass mirrors generally crack under heat and heretofore have been unacceptable where fire-resistant construction is desirable.
Another important objective of my earlier patent is personal safety. Conventional glass mirror installed in direct hung gridwork presents a possible safety hazard if impacted by a mop frame or other implement. In glass industry usage, a shatter-resistant mirror is the term used when a vinyl or other supporting sheet is adhesively secured to the back surface of a mirror, but such a structure helps to prevent shards of glass from falling from the mirror more than preventing the glass from shattering.
The overriding purpose of a mirror tile is decorative and my invention in my prior patent made mirror tiles constructed of glass safe and practical. As commercially sold under the names Image-Safe.TM., Tru-Mirror.TM. and Island Reflections.TM., trademarks of Inter-County Building Materials Corp. of Deer Park, Long Island, N.Y., such tiles have been approved under building codes and have received Underwriters Laboratories Inc. (U.L..RTM.) approval.
Notwithstanding the purpose of my prior invention to make glass tiles safer (resisting breakage but if accidentally broken, the glass fragments remain in place), there is decorative purpose in having glass mirror tiles which are intentionally cracked. There is great visual beauty in a well-silvered glass mirror which is intentionally cracked or crazed throughout. The present invention provides a structure and method of making such tiles, and providing them with adequate protection when installed.
But the invention has a broader use than the specific purpose above described. In its broad principle, the invention provides a decorative cracked glass laminate in various forms such as tiles, panels, sheets, plates, veneers and in situ applications. The intermediate layer of the laminate is a sheet of tempered glass mirror. This intermediate layer is laminated between a supportive or protective backing such as a fiberboard panel, and an outer (front) transparent sheet, e.g., a sheet of annealed glass. The intermediate tempered glass mirror is caused to crack from edge to edge by cutting into one edge, as by a rotating diamond-tipped blade.
The resulting laminate may be used as a ceiling tile, a floor tile, a wall decoration, a table or counter top, and various other applications.

Decorative cracked glass mirror tile and method


A node of a network configured to forward packets based on network programming instructions encoded in the packets, performs a method. The method includes generating a probe packet encoded with a replication network programming instruction. The replication network programming instruction is configured to validate equal-cost multi-path (ECMP) routing in the network from the node to a destination by remotely triggering transit nodes of the network, that are traversed by the probe packet, to each perform replicate-and-forward actions. The replicate-and-forward actions include: identifying ECMP paths toward the destination; generating, for the ECMP paths, replicated probe packets that each include the replication network programming instruction; and forwarding the replicated probe packets along the ECMP paths. The method further includes forwarding the probe packet toward the destination.

Network nodes (referred to simply as "nodes") of a software-defined fabric (SDF) may be interconnected in a leaf-spine topology. The nodes may employ equal-cost multi-path (ECMP) routing to forward packets along optimal ECMP paths to a destination. The network nodes advertise routes to one another and update next hop (NH) ECMP entries in forwarding tables of the network nodes based on the advertising. Often, the ECMP entries may include stale entries that do not accurately reflect recent path/link failures. Reasons for this may include slow control plane convergence, control plane-data plane synchronization problems, missing advertisement updates, and so on. The stale entries can result in packet forwarding along suboptimal paths. Operations, Administration, and Maintenance (OAM) probe techniques, i.e., sending of OAM probes through the network, may be used to detect the network failures, and thus enable the nodes to update their forwarding tables accordingly; however, conventional OAM probe techniques may fail to detect certain type of network failures due to the manner in which time-to-live (TTL) values for the probes are computed, in combination with the nature of route advertisement and forwarding table construction in the leaf-spine topology.

OAM-based suboptimal ECMP path detection in software-defined fabric


A gas generator includes an elongated cylindrical housing, an accommodation chamber defining member arranged in the housing, a gas generating agent, and an autoignition agent. The accommodation chamber defining member includes a cylindrical portion which extends in a direction in parallel to an axial direction of the housing and accommodates the gas generating agent therein. A heat insulating layer is located between the housing and the cylindrical portion. The autoignition agent is arranged in a portion inside the housing in the axial direction of the housing where no heat insulating layer is provided, as being in contact with the housing with a member made of a metal being interposed.

From a point of view of protection of a driver and/or a passenger in a car, an air bag apparatus which is a passenger protection apparatus has conventionally widely been used. The air bag apparatus is equipped for the purpose of protecting a driver and/or a passenger against shock caused at the time of collision of a vehicle, and it receives a body of a driver or a passenger with the air bag serving as a cushion by instantaneously expanding and developing the air bag at the time of collision of a vehicle.
The gas generator is equipment which is incorporated in this air bag apparatus, an igniter therein being ignited in response to power feed through a control unit at the time of collision of a vehicle to thereby burn a gas generating agent with flame caused by the igniter and instantaneously generate a large amount of gas, and thus expands and develops an air bag.
Depending on a position of installation in a vehicle and the like or on specifications such as output, gas generators of various constructions are available. A gas generator called a cylinder type gas generator represents one example. The cylinder type gas generator has an outer geometry in an elongated columnar shape and it is suitably incorporated in a side air bag apparatus, a curtain air bag apparatus, a knee air bag apparatus, or a seat cushion air bag apparatus.
Normally, in a cylinder type gas generator, an igniter is installed at one end portion in an axial direction of a housing, a combustion chamber accommodating a gas generating agent is provided on a side of the one end portion, a filter chamber accommodating a filter is provided on a side of the other end portion in the axial direction of the housing, and a gas discharge opening is provided in a circumferential wall portion of the housing in a portion defining the filter chamber.
In the cylinder type gas generator thus constructed, gas generated in the combustion chamber flows into the filter chamber along the axial direction of the housing and passes through the filter, and the gas which has passed through the filter is discharged to the outside through the gas discharge opening.
In case of fire in a vehicle equipped with an air bag apparatus incorporating a cylinder type gas generator, the cylinder type gas generator is externally heated and a temperature in the cylinder type gas generator may increase up to approximately several hundred degrees. When the temperature of the gas generating agent reaches its spontaneous combustion temperature in that case, an abnormal operation is induced.
When such an abnormal operation is induced, a pressure in the housing may increase to a pressure much higher than a designed pressure required at the time of activation of a common cylinder type gas generator due to burning of the gas generating agent because the cylinder type gas generator itself has already been in a high-temperature state due to external heating. In that case, a pressure exceeding a withstanding pressure of the housing may be applied to the housing, and consequently the housing may rupture.
Therefore, in a common cylinder type gas generator, an agent called an autoignition agent lower in spontaneous combustion temperature than a gas generating agent is loaded in the housing. Then, even when the cylinder type gas generator is externally heated, the autoignition agent ignites while a temperature is relatively low so that the gas generating agent burns and what is called an autoignition operation is exhibited. A pressure in the housing is adjusted not to reach a breaking pressure.
The autoignition agent described above is often placed, for example, in a combustion chamber where a gas generating agent is arranged, and a cylinder type gas generator constructed as such is disclosed, for example, in U.S. Pat. No. 6,851,373 (PTL 1).
In a gas generator such as a cylinder type gas generator, it is important that a gas generating agent is hermetically sealed from the outside, because desired gas output may not be obtained when the gas generating agent absorbs moisture.
A method of accommodating a gas generating agent in a gastight container formed from a relatively weak member which melts or bursts with heat or a pressure generated by activation of an igniter and arranging the gastight container in the housing is available as a method of preventing the gas generating agent from absorbing moisture in a cylinder type gas generator. A cylinder type gas generator in accordance with this method is disclosed, for example, in FIGS. 1 to 11 of Japanese Patent Laying-Open No. 2016-22930 (PTL 2).
In the gas generator disclosed in Japanese Patent Laying-Open No. 2016-22930, the gastight container is constituted of a cylindrical container body with bottom which has an opening end and a lid body which closes the opening end of the container body. Various methods such as brazing, adhesion, welding, and tightening by winding are available for joint between the container body and the lid body.