In a metallization system of a sophisticated semiconductor device, metal pillars may be provided so as to exhibit an increased efficiency in distributing any mechanical stress exerted thereon. This may be accomplished by significantly increasing the surface area of the final passivation layer that is in tight mechanical contact with the metal pillar.

1. Field of the Invention
Generally, the present disclosure relates to integrated circuits, and, more particularly, to the techniques for reducing chip-package interactions caused by thermal mismatch between the chip and the package.
2. Description of the Related Art
Semiconductor devices are typically formed on substantially disc-shaped substrates made of any appropriate material. The majority of semiconductor devices including highly complex electronic circuits are currently, and in the foreseeable future will be, manufactured on the basis of silicon, thereby rendering silicon substrates and silicon-containing substrates, such as silicon-on-insulator (SOI) substrates, viable base materials for forming semiconductor devices, such as microprocessors, SRAMs, ASICs (application specific ICs), systems on chip (SoC) and the like. The individual integrated circuits are arranged in an array on the wafer, wherein most of the manufacturing steps, which may involve several hundred and more individual process steps in sophisticated integrated circuits, are performed simultaneously for all chip areas on the substrate, except for photolithography processes, metrology processes and packaging of the individual devices after dicing the substrate. Thus, economical constraints drive semiconductor manufacturers to steadily increase the substrate dimensions, thereby also increasing the area available for producing actual semiconductor devices and thus increasing production yield.
In addition to increasing the substrate area, it is also important to optimize the utilization of the substrate area for a given substrate size so as to actually use as much substrate area as possible for semiconductor devices and/or test structures that may be used for process control. In the attempt to maximize the useful surface area for a given substrate size, the feature sizes of circuit elements are steadily scaled down. Due to this ongoing demand for shrinking the feature sizes of highly sophisticated semiconductor devices, copper, in combination with a low-k dielectric material, has become a frequently used alternative in the formation of so-called interconnect structures, comprising metal line layers and intermediate via layers that include metal lines as intra-layer connections and vias as inter-layer connections, which commonly connect individual circuit elements to provide the required functionality of the integrated circuit. Typically, a plurality of metal line layers and via layers stacked on top of each other is necessary to realize the connections between all internal circuit elements and I/O (input/output), power and ground pads of the circuit design under consideration.
For extremely scaled integrated circuits, the signal propagation delay is no longer limited by the circuit elements, such as field effect transistors and the like, but is limited, owing to the increased density of circuit elements requiring an even more increased number of electrical connections, by the close proximity of the metal lines, since the line-to-line capacitance is increased, in combination with a reduced conductivity of the lines due to a reduced cross-sectional area. For this reason, traditional dielectrics, such as silicon dioxide (k>4) and silicon nitride (k>7), are replaced by dielectric materials having a lower permittivity, which are therefore also referred to as low-k dielectrics, having a relative permittivity of 3 or less. However, the density and mechanical stability or strength of the low-k materials may be significantly less compared to the well-approved dielectrics silicon dioxide and silicon nitride. As a consequence, during the formation of the metallization system and any subsequent manufacturing processes of integrated circuits, production yield may depend on the mechanical characteristics of sensitive dielectric materials, such as low-k dielectric layers, and their adhesion to other materials.
In addition to the problems of reduced mechanical stabilities of advanced dielectric materials having a dielectric constant of 3.0 and significantly less, device reliability may be affected by these materials during operation of sophisticated semiconductor devices due to an interaction between the chip and the package caused by a thermal mismatch of the corresponding thermal expansion of the different materials. For instance, in the fabrication of complex integrated circuits, increasingly, a contact technology may be used in connecting the package carrier to the chip, which is known as flip chip packaging technique. Contrary to the well-established wire bonding techniques in which appropriate contact pads may be positioned at the periphery of the very last metal layer of the chip, which may be connected to corresponding terminals of the package by a wire, in the flip chip technology, a respective bump structure may be formed on the last metallization layer, for instance comprised of a solder material, which may be brought into contact with respective contact pads of the package. Thus, after reflowing the bump material, a reliable electrical and mechanical connection may be established between the last metallization layer and the contact pads of the package carrier. In this manner, a very large number of electrical connections may be provided across the entire chip area of the last metallization layer with reduced contact resistance and parasitic capacitance, thereby providing the IO (input/output) capabilities, which may be required for complex integrated circuits, such as CPUs, storage memories and the like. During the corresponding process sequence for connecting the bump structure with a package carrier, a certain degree of pressure and/or heat may be applied to the composite device to establish a reliable connection between each of the bumps formed on the chip and the bumps or pads that may be provided on the package substrate. The thermally or mechanically induced stress may, however, also act on the lower-lying metallization layers, which may typically include low-k dielectrics or even ultra low-k (ULK) dielectric materials, thereby significantly increasing the probability of creating defects by delamination of these sensitive materials due to reduced mechanical stability and adhesion to other materials.
Moreover, during operation of the finished semiconductor device attached to a corresponding package substrate, significant mechanical stress may occur due to a significant mismatch in the thermal expansion behavior of the silicon-based semiconductor chip and the package substrate, since, in volume production of sophisticated integrated circuits, economic constraints typically require the usage of specified substrate materials for the package, such as organic materials, which typically may exhibit a different thermal conductivity and a coefficient of thermal expansion compared to the silicon chip.
In recent developments, the thermal and electrical performance of a "bump structure" is increased by providing copper pillars instead of solder bumps or balls, thereby reducing the required floor space for individual contact elements and also enhancing thermal and electrical conductivity, due to the superior characteristics of copper compared to typically used solder material. These copper pillars may, however, contribute to an even more severe interaction between the package and the metallization system of the chip, since, typically, the copper pillars are significantly less deformable compared to the bump structures, which may be advantageous in view of electrical and thermal behavior which, however, may result in even increased mechanical stress components in a locally very restricted manner, as will be described in more detail with reference to FIG. 1.
FIG. 1 schematically illustrates a cross-sectional view of an integrated circuit 150 comprising a semiconductor die or chip 100 connected to a package substrate 180 that is substantially comprised of an organic material, such as appropriate polymer materials and the like, wherein the connection between the chip 100 and the package substrate 180 may be accomplished by means of a pillar structure 170. The semiconductor chip 100 may typically comprise a substrate 101, for instance a silicon substrate or an SOI substrate, depending on the overall configuration of the circuit layout and the performance of the integrated circuit 150. Moreover, a silicon-based semiconductor layer 102 may typically be provided "above" the substrate 101, wherein the semiconductor layer 102 may comprise a very large number of circuit elements, such as transistors, capacitors, resistors and the like, as are required for the desired functional behavior of the integrated circuit 150. As previously discussed, the ongoing shrinkage of critical dimensions of circuit elements may result in critical dimensions of transistors on the order of magnitude of 50 nm and significantly less in presently available sophisticated semiconductor devices produced by volume production techniques. The semiconductor chip 100 comprises a metallization system 110, which, in advanced devices, comprises a plurality of metallization layers, i.e., device levels, in which metal lines and vias are embedded in an appropriate dielectric material. As discussed above, at least a portion of the corresponding dielectric materials used in the various metallization layers is usually comprised of materials of reduced mechanical stability in order to produce the parasitic capacitance of adjacent metal lines. As previously explained, the pillar structure 170 may be provided as a part of the metallization system 110, wherein the corresponding copper pillars are provided in the very last metallization layer of the system 110. On the other hand, the package substrate 180 comprises appropriately positioned and dimensioned contact pads (not shown) which may be brought into contact with corresponding pillars or any solder material formed thereon, in order to establish respective mechanical and electrical connections upon application of heat and/or mechanical pressure. Furthermore, the package substrate 180 usually comprises appropriate conductive lines in order to connect the upper pillars of the pillar structure 170 with corresponding terminals, which then establish an electrical interface to other peripheral components, such as a printed wiring board and the like. For convenience, any such conductive lines are not shown.
During operation of the integrated circuit 150, heat is generated within the semiconductor chip 100, for instance caused by the circuit elements formed in and above the semiconductor layer 102. This waste heat is dissipated, for instance, by the metallization system 110 and the pillar structure 170 in a highly efficient manner and/or via the substrate 101, depending on the overall thermal conductivity of the substrate 101. For example, the heat dissipation capability of SOI substrates is significantly less compared to pure silicon substrates due to the reduced thermal conductivity of the buried insulating oxide layer, which separates the semiconductor layer 102 from the remaining substrate material. Thus, a major heat dissipation path is provided by the pillar structure 170 and the package substrate 180. Consequently, a moderately high average temperature is created in the semiconductor chip 100 and also in the package substrate 180, wherein, as previously discussed, a mismatch in the coefficient of thermal expansion between these two components may cause a significant mechanical stress. As is, for instance, indicated by arrows 103 and 173, the package substrate 180 may have an increased thermal expansion compared to the semiconductor chip 100, wherein a corresponding mismatch therefore results in a significant degree of thermal stress, in particular at the "interface" between the semiconductor chip 100 and the package substrate 180, that is, in particular the pillar structure 170 and the metallization system 110 may experience significant sheer forces caused by the thermal mismatch during the operation of the integrated circuit 150. Due to the reduced mechanical stability and the reduced adhesion of sophisticated dielectric materials, corresponding defects may occur which may affect the overall reliability of the integrated circuit 150. In particular, the stiffness of the individual pillars of the pillar structure 170 may result in locally high sheer forces, which are transferred into the entire metallization system, thereby resulting in delamination defects and the like. Consequently, although advanced contact regimes between a chip and a package substrate based on copper pillars may provide significant advances with respect to heat dissipation capabilities and electrical conductivity for a reduced required floor space, thereby allowing enhanced density of contact elements and/or dummy elements for heat dissipation, the increased mechanical stress induced in the metallization system may not be compatible with the reliability requirements of the semiconductor devices. For this reason, frequently, the height of the copper pillars is reduced which, however, may be associated with a corresponding reduction of the spacing between the package substrate and the chip, which in turn may cause a non-reliable filling in of any underfill material. Thus, corresponding voids in the underfill material may also contribute to a high degree of non-reliability, for instance caused by non-uniformities in heat conductivity and the like. In some conventional approaches, therefore, the reduced pillar height is compensated for by adding a lead-free solder cap, thereby maintaining a desired distance between the package substrate and the chip. However, a corresponding manufacturing strategy is associated with increased costs due to a significantly increased manufacturing complexity in providing the solder material on top of the copper pillars. In further conventional approaches, the metallization systems may be formed on the basis of less sensitive low-k materials or ultra low-k materials in order to enhance the mechanical stability of the metallization system, which, however, is associated with a significant reduction in electrical performance due to increased parasitic capacitances, resulting in increased signal propagation delay.
The present disclosure is directed to various methods and devices that may avoid, or at least reduce, the effects of one or more of the problems identified above.

Semiconductor device including a reduced stress configuration for metal pillars


A new method of forming a tunneling oxide film having a uniform thickness in the fabrication of a Flash EEPROM memory cell is described. A first oxide layer is provided on the surface of a semiconductor substrate wherein a portion of the first oxide layer is removed to expose the semiconductor substrate wherein the exposed portion of the semiconductor substrate comprises a tunneling window. A second oxide layer is deposited within the tunneling window. Thereafter, a thermal oxide layer is grown underlying the first oxide layer and the second oxide layer within the tunneling area wherein the presence of the second oxide layer provides for a uniform thermal oxide thickness throughout the tunneling window and wherein the second oxide layer and the thermal oxide layer together within the tunneling window form the tunneling oxide film in the fabrication of a memory cell.

1. Field of the Invention
The invention relates to a method of fabricating semiconductor memory devices employing floating gates, and more particularly, to a method of fabricating memory devices employing floating gates having an improved tunneling oxide.
2. Description of the Prior Art
One class of semiconductor memory devices employs floating gates; that is, gates which are completely surrounded by an insulating layer, such as a silicon oxide. The presence or absence of charge in the floating gates represents binary information. These are called electrically programmable read only memories (EPROM). EEPROMS are erasable electrically programmable read only memories. A tunneling oxide, necessary for the erase function of the cell, is situated below the floating gate of the memory cell. Typically, the tunneling oxide is formed by a thermal oxidation process. The inventors have found that the tunneling oxide is thinner at the edges of the thick oxide areas. This oxide edge thinning is thought to occur because there is less oxygen under the thick oxide areas to join in the oxidation reaction; thus, the growth rate of the tunneling oxide there will be lower than in the bare silicon area.
FIG. 1 illustrates a semiconductor substrate 10 on which have been formed thick oxide areas 11. Tunnel oxide 13 is grown on the surface of the substrate between the thick oxide areas 11, as shown in FIG. 2. The thickness T1 of the tunnel oxide 13 in the center portion is greater than the thickness T2 of the tunnel oxide at the edge portion by about 10 Angstroms. The thin oxide portion at the edge of the thick oxide is weak and easily damaged by charges, plasma, electric fields, etc. The weak thinning oxide will also form more surface states and charge or hole trapping centers. All of these effects reduce reliability, especially in EEPROM applications.
A similar tunneling oxide thinning has been observed adjacent to a field oxide region. This thinning is due to stress. Workers in the art have tried to improve this stress-related thinning by using a chemically vapor deposited (CVD) stacked gate oxide. This method is used in the U.S. Pat. No. 5,219,774 to Vasche and is illustrated in FIGS. 3-5. FIG. 3 illustrates a semiconductor substrate 10 in which Field OXide regions 12 have been formed. An oxide film 13 is formed by thermal oxidation, as shown in FIG. 4. It can be seen that oxide thinning occurs at the edges adjacent to the field oxide regions 12. Referring now to FIG. 5, an oxide film 14 is deposited over the thermal oxide layer 13 by chemical vapor deposition (CVD) and then densified. This smooths the film edge and improves the stress induced oxide thinning. However, the thinning effect caused by the thermal oxidation growth rate difference is not reduced.
U.S. Pat. Nos. 5,516,713 and 5,427,970 to Hsue et al, 5,352,619 to Hong, and 5,411,904 to Yamauchi et al teach methods of forming small tunneling oxide windows wherein tunneling oxide is thermally grown. U.S. Pat. No. 5,122,847 to Kamiya et al teaches forming a tunneling oxide by CVD at a high temperature of 700.degree. C. or more for a film with a higher breakdown current density.

Ultra thin tunneling oxide using buffer CVD to improve edge thinning

Taiwan Semiconductor Manufacturing Company Ltd.


Authentication employs a classification that monitors content of authentication requests and results and assigns and records risk values identifying low-risk sources making normal authentication requests and high-risk sources making abnormal authentication requests indicative of fraud activity. Then for low-risk sources, a normal authentication process is employed having differential success/fail behavior exposing information about an enumerable system resource, such as a user account. Example differential behavior includes (a) granting access when a request identifies a valid user account, and (b) otherwise denying access, enabling an attacker to learn whether a guessed value identifies an existing account. For high-risk sources, a false authentication process is employed having non-differential success/fail response behavior that does not expose the information, such as consistent presentation of a service denial message irrespective of whether the request identifies a valid existing user account, preventing an enumeration attack.

The present invention is related to the field of user authentication in computer systems. Computer systems generally, and in particular computer systems providing services over publically accessed networks, are vulnerable to a variety of attacks by which an attacker obtains unauthorized access to system resources. One type of attack, which may be used as a prelude to other, more targeted attacks, is an enumeration attack in which an attacker makes a series of attempts to access a system and observes the system's response so as to glean information about system resources. One well known example involves enumeration of account identifiers (IDs). An attacker generates a series of system login requests containing guessed-at account IDs that may or may not match valid IDs of accounts of the system. If the system responds differently to login attempts containing IDs that match valid IDs than to login attempts containing IDs that do not match valid IDs, then by observing this differential behavior the attacker learns or "enumerates" the accounts existing in the system. This specific information can then be used in subsequent attacks that are more targeted to the specific existing accounts.

User authentication avoiding exposure of information about enumerable system resources


The portable combination cooler and cushioned seat is a cooler and seat combination configured for easy and quick attachment to a standard stadium bench. The cooler has an insulated six-sided housing with a drawer for storing food and beverages. Attached to the top of the housing is a set of seat mounting brackets, each with a collapsible back support, which facilitates mounting onto a standard stadium bench seat. A folding cushioned seat is attached to the top of the seat mounting brackets. The housing also includes a retractable table, an elastic side pouch and a detachable carrying strap.

1. Field of the Invention
The present invention relates to coolers, and more particularly to a portable cooler and seat combination that can be slidably attached to a stadium bench with the cooler positioned under the bench and the seat positioned on top of the bench.
2. Description of the Related Art
Conventional coolers are known in the art and generally consist of an insulated container for keeping food and beverages cool at an outdoor location. Typically, a cooler has six sides including a top, bottom, front, back, left side and right side. The top often is comprised of a removable lid that provides access to the contents of the cooler and also serves as a makeshift seat when the cooler is closed.
A notable drawback of a conventional cooler is that it is bulky and cumbersome. For example, when brought to an event taking place in a stadium, such as a NASCAR race or an athletic event, a conventional cooler must often be placed on a stadium bench, where it takes up valuable seating space, or where it must be stored in an aisle, stairway or walkway, thereby obstructing easy passage for patrons.
Additionally, when used as a seat, the top of a conventional cooler is not comfortable and does not provide enough space to also set a drink or other item thereon. Furthermore, as items within the cooler are desired, a person sitting on the cooler must repeatedly stand up.
Therefore, a need exists for a portable cooler that can be used in a stadium without taking up seating space or restricting access to aisles, stairways or walkways. Additionally, a need exists for a cooler that can be used as a seat where the person sitting on the cooler is comfortable and does not have stand up each time the contents of the cooler is accessed. Furthermore, a need exists for a cooler that can be used as a seat in conjunction with a standard stadium bench to provide comfortable seating while allowing the cooler to be stored in an out-of-the-way place.
U.S. Design Pat. No. 330,639, issued Nov. 3, 1992 to D. S. Munro et al., shows a portable seat having a seat portion, a backrest and a cooler compartment that is accessed by lifting the seat portion. Because the cooler compartment is accessed by lifting the seat portion, a person sitting on the device must stand up each time the cooler is accessed. Additionally, if used by a person sitting on a bench, the person is elevated by the height of the cooler compartment, and thereby his or her feet may be unable to reach the ground.
U.S. Pat. No. 5,100,198, issued Mar. 31, 1992 to R. L. Baltzell, describes a combined set and cooler adapted for use on a beach. The device is not useful for providing comfortable seating in conjunction with a stadium bench nor is it adapted to out-of-the-way storage.
U.S. Design Pat. Nos. 197,558 and 200,309, issued Feb. 25, 1964 and Feb. 16, 1965, respectively, to A. Sokolis (combined folding chair and tackle box); and U.S. Design Pat. No. 298,186 issued Oct. 25, 1988 to J. J. Brannon (combined seat and cooler unit), each show a combination seat and container with a removable or foldable backrest and with a lid serving as the top to the container. Because the lid must be opened to access the contents of the container, a person sitting on the seat must stand up each time the container is accessed.
U.S. Design Pat. No. 180,542, issued Jul. 2, 1957 to S. Barrow (sewing chair); U.S. Design Pat. No. 240,781 issued Aug. 3, 1976 to K. R. Kohler (fisherman's chair); U.S. Design Pat. No. 274,581 issued Jul. 10, 1984 to J. P. Gallock (combination chair and drawer); U.S. Pat. No. 2,264,744 issued Mar. 3, 1941 to R. A. Dunnam (combined tackle box and seat); and U.S. Pat. No. 4,652,048 issued Mar. 24, 1987 to R. C. Nazar (portable adjustable chair with insulated seat cooler), all teach a device incorporating a seat disposed on top of a housing that has a drawer or other laterally accessed compartment. None of the devices, however, is suitable for use in conjunction with a stadium bench.
U.S. Pat. No. 5,660,296, issued Aug. 26, 1997 to R. E. Greenwich (mobile cooler having a removable cover usable as a chair); U.S. Pat. No. 5,727,844, issued Mar. 17, 1998 to J. L. O'Quinn et al. (cooler seat system); and U.S. Pat. No. 6,341,817, issued Jan. 29, 2002 to E. Stern-Gonzalez (conventional cooler with reclinable seat back and seat), all teach conventional coolers with lids adapted for a person to sit on. The coolers are cumbersome and a person using one as a seat would have to stand up each time its contents is accessed.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, a portable combination cooler and cushioned seat adapted for attachment to a bench solving the aforementioned problems is desired.

Portable combination cooler and cushioned seat


An active suspension system, particularly for vehicles, having supporting units which each have an actively lift-adjustable regulating unit and a passive spring arranged in series thereto. Preferably, a damper is arranged at least in parallel to the spring. By use of various acceleration sensors, lifting, pitching, rolling, longitudinal and lateral accelerations of the vehicle body can be determined. By use of path sensors, the lifting positions of the supporting units are registered. A signal analysis permits the achievement of a definable suspension characteristic.

The invention relates to an active suspension system, particularly for vehicles, having supporting units, which each have an actively lift-adjustable regulating unit and a passive spring arranged in series thereto, and having an automatic control of the regulating units, a path sensor for generating a signal correlated with the lifting position of the supporting unit being assigned to each supporting unit, and an arrangement of acceleration sensors being provided on the vehicle body for generating signals for body-side longitudinal and lateral accelerations as well as lifting movements, and control signals used for controlling the regulating units comprising a first proportion generated by signals of acceleration sensors and a second proportion generated by signals of path and acceleration sensors.
A suspension system of the type generally described above is the object of German Patent Document DE 39 32 476 A1. According to this document, hydropneumatic spring and supporting units are provided in the case of which the passive spring is formed by a pneumatic spring loading device. This spring is hydraulically connected with a piston working space of a piston-cylinder unit arranged between the sprung and the unsprung mass, in which case the hydraulic "linkage" formed by the hydraulic connection can be lengthened or shortened by the feeding or removal of hydraulic medium.
The first proportion of the control signals is determined by the longitudinal and lateral acceleration by the vehicle body. The second proportion of the control signals depends on the lifting path of the unsprung mass relative to the sprung mass as well as the vertical acceleration of the sprung mass.
German Patent Document DE 42 31 641 A1 as well as German Patent Document DE 44 14 022 A1 show active suspension systems, in which a passive mechanical spring is arranged in series to a hydraulic regulating unit by means of which the lifting position of the unsprung mass can be changed relative to the sprung mass or lift adjustments can be generated which are superimposed on the spring lift of the passive spring.
From German Patent Document DE 41 39 412 A1, an active suspension system is known in which small, obviously hard passive springs are provided which are constructed only for influencing higher-frequency movements of the tire or wheel, which have lower amplitudes, and are constructed as hydropneumatic springs. These springs are combined with adjustable dampers.
German Patent Document DE 42 17 325 A1 relates to an active vehicle suspension in the case of which individual natural vibration forms of the body can be influenced separately from one another in the sense of a "Skyhook" damping.
According to German Patent Document DE 29 43 486 C2, it is provided to assign to each supporting unit of an active suspension system, in the case of which one lift-adjustable regulating unit respectively is arranged in series to a passive suspension; a path sensor for determining the regulating path of the regulating unit; as well as a vehicle-body-side acceleration generator for determining the body-side vertical acceleration. From the signals of the acceleration generator, in addition to the acceleration signals, other signals are determined by calculation for the vertical velocity and the vertical position of the vehicle body. The regulating units are then in each case controlled as a function of their lifting position as well as of the signals for the vertical acceleration, the vertical velocity and the vertical position of the vehicle body. As a result, a good damping of the vehicle body movements is endeavored.
In addition, it is basically known, for example, from German Patent Document DE 43 03 160 A1 to provide, in the case of chassis systems, only one actively controllable regulating unit respectively between the vehicle body and the wheel, without providing an additional passive spring arranged in series with the regulating unit and to carry out the controlling of these regulating units as a function of parameters to be monitored by means of a desired-value/actual-value comparison. Systems of this type must have an extremely high reaction capacity of the regulating units as well as of the regulating paths. Otherwise, because of the lack of flexible passive elements between the wheel and the vehicle body, the suspension action would be extremely uncomfortable.


On one surface of a piece of wooden sheet, a cloth or paper is adhered to make an adhered sheet. An approximately V-shaped notch is provided on the adhered sheet, the adhered sheet is wetted to be softened, and a lubricant which acts to keep water is impregnated thereinto. Edge portions of the notch are overlapped, and the adhered sheet is tentatively molded in an approximately horn shape by a first hot press molding. The adhered sheet is then dried, impregnated with thermosetting resin, and half-dried. The adhered sheet is subject to a second hot press molding. A moisture-proof agent is applied on the adhered sheet, a center hole for a voice coil and periphery are removed to make a speaker diaphragm having a predetermined dimension and shape.

1. Field of the Invention
The present invention relates to speaker diaphragms used for audio speakers, manufacturing methods of the same, and dynamic speakers.
2. Description of the Related Art
Conventional diaphragms for dynamic speakers are inmost cases made of paper pulp, plastic or metal such as aluminum. These conventional diaphragms are made by press molding of a homogeneous material, and therefore, velocities of sounds propagated from the center of the diaphragm in various radial directions thereof are equal to each other. Accordingly, with regard to the conventional diaphragms, standing waves are always generated and resonance points appear. Moreover, sound pressure frequency characteristics are deteriorated due to split vibrations in low frequency regions. Furthermore, feeling of being at a live performance or the like will be lost.
In addition, although the diaphragms made of paper pulp or plastic have relatively high internal loss coefficients, they are not good in terms of stiffness (Young's modulus), and sound wave velocities thereof are low. Definition of the reproduced sounds is therefore not satisfying. In contrast, the diaphragms made of metal such as aluminum have high sound wave velocities. However, the internal loss coefficients thereof are low, and therefore, amplitude attenuation is small. Consequently, there is a drawback that reproduced sounds are not clearly divided (that is sounds are not sharp).
Instead of such diaphragms made of existing materials, which have both advantages and drawbacks, wooden diaphragms are desired to be realized as speaker diaphragms that can reproduce more natural sounds.
The sound wave velocities of wood vary according to the kinds of wood. However, in general, wood has higher sound wave velocities than paper pulp. Moreover, the sound wave velocities in the grain direction and those in a direction perpendicular to the grain are different from each other. Wood has an anisotropic propagation characteristic, in which the propagation velocities in the grain direction (referred to as a "longitudinal direction") are relatively high, while the propagation velocities in the direction perpendicular to the grain (referred to as a "horizontal direction") are relatively low. Moreover, in general, wood has internal loss coefficients appropriate as speaker diaphragms, and is light and strong (high stiffness).
Hence, with regard to the wooden diaphragms, in which wood is used as basis material as it is, standing waves are not generated normally and resonance points hardly appear. Therefore, it can be expected that sound pressure frequency characteristics in low frequency regions are improved, and definition and sharpness of the reproduced sounds can be enhanced compared to the existing diaphragms made of paper pulp.
Various manufacturing methods have already been proposed in, for example, the following publicly known documents as manufacturing methods of wooden diaphragms or dynamic speakers employing the wooden diaphragms.
In Japanese Patent Laid-Open No. Sho 62(1987)-224196 (Patent Document 1), described is a speaker using, as a flat diaphragm for the speaker, a thin, flat wooden board treated to a wood plastic combination (WPC). Here, the thin, flat wooden board is impregnated with plastic such as polyester.
In Japanese Patent Laid-Open No. Hei 1(1989)-288100 (Patent Document 2), described is a cone diaphragm 5 manufactured through a manufacturing procedure shown in FIGS. 1A and 1B. As shown in FIG. 1A, a wooden sheet 1, a development of an approximately horn shape, which has a circular cutout portion 1a in the center thereof and a sector-shaped cutout portion 1b extended from the cutout portion 1a, is removed from one sheet of thin wooden board 4. Then, as shown in FIG. 1B, both edge portions b1 and b2 of the sector-shaped cutout portion 1b are overlapped with each other on an overlapping portion 1c, and adhered with an adhesive to be formed into the approximately horn shape. Thereafter, the wooden sheet 1 is press molded to be a cone diaphragm 5.
In addition, in Patent Document 2, it is described that a plurality of small wooden pieces 2a to 2L shown in FIG. 2A are adhered with an adhesive, made into an approximately horn shape as shown in FIG. 2B, and then press molded to be a cone diaphragm 2. It is also described that physical moisture-proof treatment or chemical moisture-proof treatment is performed onto, the cone diaphragms 2 and 5.
In Japanese Patent Laid-Open No. Hei 5(1993)-83792 (Patent Document 3), an acoustic diaphragm molded in a circular cone shape is described. This diaphragm is produced as follows: a composite sheet made up of a sliced, extremely thin wooden sheet with a thickness of 80 ,,m or less and a non-woven cloth of adhesive resin attached on the back surface thereof are plasticized with a plasticizer; and a plurality of the composite sheets are stacked, heated and pressed.
In Japanese Patent Laid-Open No. Hei 6(1994)-178386 (Patent Document 4), described is a cone diaphragm which is produced as follows: a thin, flat wooden board is cut into a sector shape; the thin wooden board is boiled in hot steam, hot water, or an alkaline solution of pH 10 or more in order to prevent cracks upon molding; and the thin wooden board is press molded into a circular cone shape.
In Japanese Patent Laid-Open No. Hei 10(1998)-304492 (Patent Document 5) described is a speaker diaphragm which is produced as follows: a thin non-woven cloth or Japanese paper is adhered on one surface of a piece of wooden sheet to make an adhered sheet; the adhered sheet is impregnated with a lubricant to get tension and flexibility; and the adhered sheet impregnated with the lubricant is hot press molded to be made into an approximately horn shape.
In Japanese Patent Laid-Open No.2000-59883 (Patent Document 6), described is a speaker diaphragm which is produced as follows. In order to produce a wooden speaker diaphragm in which no wrinkles or cracks occur upon press molding and deterioration with time is small, on one surface of a piece of wooden sheet, a thin non-woven cloth, Japanese paper or a carbon sheet is adhered to make an adhered sheet, and the adhered sheet is impregnated with thermosetting resin. Then, the adhered sheet is hot press molded to be made into an approximately horn shape.
With respect to a wooden speaker diaphragm, it is a key to deal with the characteristics of wood, which is a basis material that easily cracks, the poor moldability thereof, and the deterioration thereof with age.
In above-mentioned Patent Document 1, a manufacturing method of molding and making the diaphragm into an approximately horn shape (or cone shape) is not described, since the diaphragm is a flat diaphragm. In the manufacturing methods of Patent Document 2 shown in FIGS. 1A and 1B and FIGS. 2A and 2B, respectively, the wooden sheet 1 and the small wooden pieces 2a to 2L are molded while the characteristics of the wood are maintained as they are. Therefore, cracks may occur upon handling or press molding of the wooden sheets. Moreover, since the wooden sheets are adhered to each other with an adhesive, there are problems that desired sound characteristics cannot be obtained and accuracy in dimensions cannot be secured because the adhered portions become obstacles.
As for the method described in Patent Document 3, in which a plurality of extremely thin wooden sheets are stacked and press molded, accurate processing thereof is rather difficult. Moreover, since there are more adhesive layers, the weight of the diaphragm itself becomes heavier due to the weight of the adhesive. As a consequent, desired sound characteristics cannot be obtained. The great amount of adhesive imposes adverse effects on the sound pressure frequency characteristics. Therefore, the method is not preferable.
In the manufacturing method described in Patent Document 4, a boiling process using hot steam or an alkaline solution of pH 10 or more is included. This method removes even lignin, a constituent material in the wood. As a result, characteristics intrinsic to the wood cannot be exhibited, which imposes adverse effects on the sound quality.
Above all, in the manufacturing methods described in Patent Documents 2 to 4, defects such as cracks, chaps and wrinkles are often generated. Therefore, in considering the mass production of the diaphragms, yield of thereof is extremely poor. Thus commercialization thereof have not been realized.
The manufacturing methods described in Patent Documents 5 and 6 are more suitable than those in Patent Documents 2 to 4 in terms of mass production. However, it cannot be said that a manufacturing method which offers sufficient moldability and excellent mass productivity has been accomplished. Accordingly, further improvement in moldability, realization of beautifully finished wooden diaphragms, and establishment of mass productivity are desired in order to commercialize the wooden diaphragms.

Speaker diaphragms, manufacturing methods of the same, and dynamic speakers


A system and process for maximizing the generation of marketable products from a variety of hydrocarbon feedstocks. The hydrocarbon feedstocks are first gasified and then oxidized in a two-chamber system and process using oxygen gas rather than ambient air. Intermediate gases generated in the system and process are recirculated and recycled to the gasification and oxidation chambers in order to maximize both energy generation and the resulting stoichiometric reaction products. The energy produced through the system and process is used to generate steam and produce power through conventional steam turbine technology. In addition to the release of heat energy, the hydrocarbon feedstocks are oxidized to the pure product compounds of water and carbon dioxide. The carbon dioxide is subsequently purified and marketed. The water recovered from the system and process is collected and electrolyzed to generate oxygen and hydrogen gases. These gases are separated using conventional gas separation technologies and also marketed. The system and process minimizes environmental emissions.

1. Field of the Invention
This invention relates to the complete combustion of hydrocarbon materials to maximize the generation of energy and stoichiometric products. In particular, the invention relates to a complete combustion process and system which is arranged and designed to gasify and oxidize a variety of solid and/or liquid hydrocarbon materials to produce energy, carbon dioxide, and water. The invention further relates to recycling and optimizing intermediate compounds produced through the gasification and oxidation processes to maximize energy, carbon dioxide, and water production. More particularly, the invention relates to the complete combustion of hydrocarbon feedstocks and the subsequent electrolysis of the water product to generate recoverable oxygen and hydrogen gases.
2. Description of the Prior Art
Gasification is a thermo-chemical process that converts hydrocarbon-containing materials into a combustible gas called producer gas. Producer gas contains carbon monoxide, hydrogen, water vapor, carbon dioxide, tar vapor and ash particles. Gasification produces a low-Btu or medium-Btu gas, depending on the process used. Producer gas contains 70-80% of the energy originally present in the hydrocarbon feedstock. The producer gas can be burned directly for heat energy, or it can be burned in a boiler to produce steam for power generation. Medium-Btu producer gas can be converted into a liquid fuel, such as methanol.
Solid/liquid hydrocarbon gasification is a two-stage process. In the first pyrolysis stage, heat vaporizes the volatile components of the hydrocarbon in the absence of air at temperatures ranging between 450° to 600° C. (842° to 1112° F.). Pyrolysis vapor consists of carbon monoxide, hydrogen, methane, volatile tars, carbon dioxide, and water. The charcoal (char) residue contains about 10-25% of the original feedstock mass. The final stage of gasification is char conversion which occurs at temperatures between 700° to 1200° C. (1292° to 2192° F.). The charcoal residue from the pyrolysis stage reacts with oxygen to produce carbon monoxide as a product gas.
The gasification process is, therefore, a controlled process wherein sufficient air/oxygen is provided to the gasifier to facilitate the conversion (i.e., reduction) of most tar, char, and other solid gasification products into synthetic gas (i.e., syngas), consisting primarily of carbon monoxide and hydrogen. Thus, the vast majority of products resulting from the gasification process are intermediate volatile gases. Gasification processes may use either air or oxygen to reduce the organic content of the waste. Oxygen reduction has the advantage of preventing the syngas from becoming diluted with nitrogen.
Gasification (and pyrolysis) are thermal reactions carried out to less than full oxidation by restricting the available oxygen/air. These processes always produce gas. Moreover, they can be optimized to produce mainly syngas, which has a significant fuel value. The production of dioxin is also very low in gasification due to the restricted availability of oxygen. In fact, dioxin emission in exhaust gases and its concentration in the gasification residues have proved to be below detectable limits. Gasification reactions are typically exothermic. However, syngas contains virtually all of the energy of the original hydrocarbon feedstock. For example, syngas produced through the gasification process can then be combusted at a temperature of 850° C. to provide an exhaust gas containing essentially all the energy of the original feedstock.
Current gasification technologies generally utilize processed waste or refuse-derived-fuel (RDF) containing a 6 to 7% moisture content to produce syngas. Gasification temperatures are normally maintained in the range of 600° to 1200° C. This moisture content enables hydrolysis and gasification to occur together. Conversion efficiency varies, but efficiencies as high as 87% have been reported. At high temperatures, oxygen preferentially reacts with carbon to form carbon monoxide/carbon dioxide rather than with hydrogen to form water. Thus, hydrogen is produced at high temperatures, especially when there is an insufficient oxygen/air supply to the gasifier.
The syngas produced from the gasification of 1 mole of C20H32O10 has an energy content of 7805 kilojoules (kJ). In contrast, the energy content of 1 mole of C20H32O10 that is released upon combustion is 8924 kJ. The energy required to heat the hydrocarbon feedstock to gasification temperatures accounts for this difference in available energy content. In this example, the efficiency of converting the RDF to syngas fuel is 87.5%. Based on these values, the total energy produced through gasification of the RDF would be 0.87 times the combustion value of the RDF.
The oxidation process is simply the exothermic conversion of producer gas to carbon dioxide and water. In a traditional combustion process, gasification and oxidation occur simultaneously. In the combustion process, the intermediate gasification products are consumed to produce carbon dioxide, water, and other less desirable combustion products, such as ash. For example, burning a solid hydrocarbon, such as wood, produces some pyrolytic vapors, but these pyrolytic vapors are immediately combusted at temperatures between 1500° to 2000° C. to produce carbon dioxide, water and other combustion products. In contrast, the gasification process is controlled, allowing the volatile gases to be extracted at a lower temperature before oxidation. Oxidation varies from incineration processes in that oxidation alters a compound by adding an electro-positive oxygen atom to the compound whereas incineration yields heat by reducing a compound to ash.
The invention disclosed herein optimizes the controlled environment of the gasification and oxidation processes through ingenious product recycle streams and operating conditions. The invention thus provides maximum energy production and product utilization from a given hydrocarbon feedstock with minimal atmospheric emissions.
The underlying technologies described herein are further disclosed in U.S. Pat. Nos. 5,906,806; 6,024,029; 6,119,606; 6,137,026; and 6,688,318, all of which are issued to Clark and hereby incorporated by reference. U.S. Patent Publication No. 2004/0134517, also by Clark, discloses related technologies and is hereby incorporated by reference. This application is based upon U.S. provisional patent application No. 60/848,697, also by Clark, which is hereby incorporated by reference.

This patent is subject to a terminal disclaimer.

Reduced-emission gasification and oxidation of hydrocarbon materials for hydrogen and oxygen extraction


Computer implemented methods are disclosed for detecting bot-user groups that send spam email over a web-based email service. Embodiments of the present system employ a two-prong approach to detecting bot-user groups. The first prong employs a historical-based approach for detecting anomalous changes in user account information, such as aggressive bot-user signups. The second prong of the present system entails constructing a large user-user relationship graph, which identifies bot-user sub-graphs through finding tightly connected subgraph components.

Conservative estimates indicate that well over half of all emails sent worldwide are spam emails. In the United States alone, it has been determined that spam email cost organizations more than $13 billion in 2007, including lost productivity and the additional equipment, software, and manpower needed to combat spam email. One factor exacerbating the problem is the ability of spammers to create and use "botnets." Botnets are networks of zombie computers that have been infected with malicious code (a bot) allowing a spammer to send spam through these bot host computers, unknown to the computer owners.
Recently, a particularly malicious botnet spamming method has evolved, where spammers use a botnet to sign up large numbers of user accounts (bot-user accounts) on the public webmail services such as Hotmail® web-based e-mail service. While security protocols, such as CAPTCHA, exist to prevent this practice, spammers are becoming more sophisticated in their methods to defeat such security protocols. As one example, a large number of bots are used to sign up a large number of fake bot-user email accounts. These bots retrieve the signup forms and pass the CAPTCHA (usually images or audio files) back to a central server. This central server is connected to a number of CAPTCHA solvers, which may be human beings and/or bot CAPTCHA breakers. The solution of the CAPTCHA, once found, is sent back to the corresponding bot which then fills the signup form and finishes the signup. Trojan.Spammer.HotLan is one example of a typical worm for email account signup discovered by BitDefender.
Once created, these bot-user accounts are then used by spammers to send out large numbers of spam emails. Using this method, millions of fake email accounts have been created during a short period, and then these bot-user accounts have been used to send out billions of spam emails.
Detecting and defending against this new type of attack has been challenging. Bot-users send spam emails through legitimate Web email providers, making the widely used mail server reputation-based approach to spam detection ineffective. Furthermore, bot-users are sharing computers with legitimate users, making it difficult to detect them individually. Making the problem even harder to detect is the fact that the spammers are using an entire botnet of bot-user accounts. Thus, no single account is sending out high volumes of spam.


Herb oil pressing devices and methods are provided. The devices include a pair of closable opposed jaws that can apply pressure to a herb placed between the jaws; a motor connected to the jaws for controlling the closing of the jaws, and, when closed, controlling the pressure produced between the jaws; a heater connected to the jaws for heating the jaws and herb; a housing in which the jaws, the motor, and the heater are housed; and a user interface connected to the jaws and the heater, the user interface for inputting a selection of temperature, pressure, and amount of time the temperature and pressure is applied to a herb positioned between the jaws to extract oil therefrom. Related computer-implemented methods of pressing a herb are also provided.

It can be desirable to press herbs to extract oils within the herbs. However, the quality and quantity of the oil extracted will depend on not only the type or variety of herb from which the oil is extracted, but also the specific pressure applied to the herb, the amount of time of applying the pressure, and the temperature at which the pressure is applied. For example, applying relatively high pressure, for a relatively short period of time, at relatively high heat may result in desired composition, quantity, and quality of oil in one situation, whereas in another situation it may be desirable to apply a relatively lower pressure, for a relatively longer period of time, at a relatively lower temperature.
Manual herb oil presses are available, but it can be difficult to repeat with accuracy a specific pressing procedure (e.g., the pressure applied, temperature at which the pressure is applied, and amount of time of applying the pressure and temperature) that results in a desired oil extraction. Automatic herb oil presses are also available that can repeat a specific pressing procedure, but can be limited to only one particular pressing procedure, which may not be optimal for the user's needs. Further, many automatic herb oil press designs may not create sufficient pressure to extract oil from some herbs. Some automatic herb oil press designs utilize a hydraulic press to press the herbs, which makes these automatic herb oil presses bulky, expensive, and not suitable for personal or small-scale use.
Further, herb oil presses are not currently available that allow a pressing procedure to be shared between pressing devices. Sharing pressing procedures between devices can allow for different users to share a herb pressing procedure that has proven successful in extracting a desired oil from a specific type or variety of herb.
Accordingly, there is a need for herb oil press devices and methods that can enable the user to fully control, customize, and accurately repeat herb pressing procedures for personal or small-scale use. Further, it is desirable to have a herb oil pressing device that can allow a user to save and share various herb pressing procedures with others.

Herb oil pressing device and related method of pressing herbs


An optical device includes a base; an image sensor disposed on the base; an outer frame connected to the base and having a flat surface; an inner frame having a protrusion and movable between a first position and a second position with respect to the base; and a lens group disposed on the inner frame and having an optical axis, wherein the protrusion abuts the flat surface and the optical axis extends through the image sensor when the inner frame moves to the first position, and the inner frame is accommodated in a space when the inner frame moves to the second position.

1. Field of the Invention
The invention relates to an optical device and a stabilizing method for optical elements thereof, and more particularly to an optical device and a stabilizing method for optical elements thereof by utilizing a protrusion to increase structural stability of elements of the optical device.
2. Description of the Related Art
When a camera is turned on, a lens may stretch out to receive light. In such a structure, lens groups are generally designed to be rotatable between a working position and a withdrawing position wherein the lens group in the working position enables an image to be formed on an image sensor. When the camera is turned off, the lens groups move to retract into the camera by overlapping with each other. As cameras are required to be lighter and slimmer, the entire structure is therefore required to be more compact. Thus, the lens groups are designed to be rotatable to have a compact structure after the lane groups overlap with each other. When the camera is turned on, the lens groups are rotated to their working position so that light can pass through the lens groups to form an image on the image sensor. When the camera is turned off, the lens groups are rotated to their withdrawing position to facilitate their accommodation. The structure of cameras is disclosed in Taiwan patent publication no. 201232027 and Taiwan patent publication no. 2013160691.
When the lens groups move from the withdrawing position to the working position, an inner frame carrying lens is positioned by abutting an outer frame so that light can pass through the lens groups to form an image on the image sensor. Referring to FIG. 1, a conventional optical lens includes a rotatable gear 10 which engages with a driving gear 22 disposed on an inner frame 20. The inner frame 20 carries a lens group (not shown) and is rotatably disposed on an outer frame 30. The rotatable gear 10 rotates to move the inner frame 20 between a working position and a withdrawing position. FIG. 1 shows the inner frame 10 in the working position. The inner frame 20 has a first positioning surface 24, and the outer frame 30 has a second positioning surface 34 corresponding to the first positioning surface 24. When the inner frame 20 moves from the withdrawing position to the working position shown in FIG. 1, the first positioning surface 24 abuts the second positioning surface 34 for positioning the inner frame 20.
Referring to FIGS. 2 to 4, as the first positioning surface 24 and the second positioning surface 34 are flat surfaces, the contact position of the first positioning surface 24 and the second positioning surface 34 depends on the shape and tolerance of the inner frame 20 and the outer frame 30, which is possibly on upper side (as shown in FIG. 2), on lower side (as shown in FIG. 3) or uncertain (as shown in FIG. 4). The uncertain contact position may cause uncertain position of the inner frame 20 when the inner frame 20 moves to the working position, which may causes unstable optical property of the optical lens.

Optical device and stabilizing method for optical elements thereof


A system and method are provided for depositing a release layer/film on a cleaner roller in an image forming device to facilitate effective cleaning of a reimageable surface in an image forming device using a proposed variable data digital lithographic image forming architecture. A borax or other solute solution is deposited on a surface of a cleaner roller and an air knife is used to evaporate a liquid component of the solution causing the liquid to come off and a thin-film of borax or other solute to remain on the surface of the cleaner roller. The thin film layer is then dry at a point of contact with the reimageable surface to recover residual ink from the reimageable surface with the surface of the cleaner roller on top of the thin film layer. The thin film layer is re-wetted to support efficient transfer of the ink to a web.

1. Field of Disclosed Subject Matter
This disclosure relates to systems and methods for providing a release layer/film on a cleaner roller to facilitate more effective cleaning of a reimageable surface in an image forming device using a proposed variable data digital lithographic image forming architecture.
2. Related Art
U.S. Patent Application Publication No. 2012/0103212 A1 (the 212 Publication) published May 3, 2012, and based on U.S. patent application Ser. No. 13/095,714, which is commonly assigned, and the disclosure of which is incorporated by reference herein in its entirety, proposes systems and methods for providing variable data lithographic and offset lithographic printing or image receiving medium marking in image forming system. The systems and methods disclosed in the 212 Publication are directed to improvements on various aspects of previously-attempted variable data imaging lithographic marking concepts to achieve effective truly variable digital data lithographic printing.
According to the 212 Publication, a reimageable surface is provided on an imaging member, which may be a drum, plate, belt or the like. The reimageable surface may be composed of, for example, a class of materials commonly referred to as silicones, including polydimethylsiloxane (PDMS) among others. The reimageable surface may be formed of a relatively thin layer over a mounting layer, a thickness of the relatively thin layer being selected to balance printing or marking performance, durability and manufacturability.
The 212 Publication describes, in requisite detail, an exemplary variable data lithography system 100 such as that shown, for example, in FIG. 1. A general description of the exemplary system 100 shown in FIG. 1 is provided here. Additional details regarding individual components and/or subsystems shown in the exemplary system 100 of FIG. 1 may be found in the 212 Publication.
As shown in FIG. 1, the exemplary system 100 may include an imaging member 110. The imaging member 110 in the embodiment shown in FIG. 1 is a drum, but this exemplary depiction should not be read in a manner that precludes the imaging member 110 being a plate or a belt, or of another known configuration. The imaging member 110 is used to apply an inked image to an image receiving media substrate 114 at a transfer nip 112. The transfer nip 112 is produced by an impression roller 118, as part of an image transfer mechanism 160, exerting pressure in the direction of the imaging member 110. The exemplary system 100 may be used for producing images on a wide variety of image receiving media substrates 114. The 212 Publication also explains the wide latitude of marking (printing) materials that may be used, including marking materials with pigment densities greater than 10% by weight. As does the 212 Publication, this disclosure will use the term ink to refer to a broad range of printing or marking materials to include those which are commonly understood to be inks, pigments, and other materials which may be applied by the exemplary system 100 to produce an output image on the image receiving media substrate 114.
The 212 Publication depicts and describes details of the imaging member 110 including the imaging member 110 being comprised of a reimageable surface layer formed over a structural mounting layer that may be, for example, a cylindrical core, or one or more structural layers over a cylindrical core.
The exemplary system 100 includes a dampening solution subsystem 120 generally comprising a series of rollers, which may be considered as dampening rollers or a dampening unit, for uniformly wetting the reimageable surface of the imaging member 110 with a dampening solution. A purpose of the dampening solution subsystem 120 is to deliver a layer of dampening solution, generally having a uniform and controlled thickness, to the reimageable surface of the imaging member 110. As described in the 212 Publication, the dampening solution may be composed of a fountain solution generally comprising water optionally with small amounts of isopropyl alcohol (IPA) or ethanol added to reduce surface tension, as well as to lower evaporation energy necessary to support subsequent laser patterning, as will be described in greater detail below. Small amounts of certain surfactants may be added to the dampening solution as well to adjust the inking and transfer properties of the reimageable surface of the imaging member 110. Experiments continue to determine an optimal release layer dampening solution.
Once the dampening solution is metered onto the reimageable surface of the imaging member 110, a thickness of the dampening solution may be measured using a sensor 125 that may provide feedback to control the metering of the dampening solution onto the reimageable surface of the imaging member 110 by the dampening solution subsystem 120.
Once a precise and uniform amount of dampening solution is provided on the reimageable surface of the imaging member 110, an optical patterning subsystem 130 may be used to selectively form a latent image in the uniform dampening solution layer by image-wise patterning the dampening solution layer using, for example, laser energy. The reimageable surface of the imaging member 110 should ideally absorb most of the laser energy emitted from the optical patterning subsystem 130 close to the surface to minimize energy wasted in heating the structural mounting layer and to minimize lateral spreading of heat in order to maintain a high spatial resolution capability. Alternatively, an appropriate radiation sensitive component may be added to the dampening solution to aid in the absorption of the incident radiant laser energy. While the optical patterning subsystem 130 is described above as being a laser emitter, it should be understood that a variety of different systems may be used to deliver the optical energy to pattern the dampening solution.
The mechanics at work in the patterning process undertaken by the optical patterning subsystem 130 of the exemplary system 100 are described in detail with reference to FIG. 5 in the 212 Publication. Briefly, the application of optical patterning energy from the optical patterning subsystem 130 results in selective evaporation of portions of the layer of dampening solution.
Following patterning of the dampening solution layer by the optical patterning subsystem 130, the patterned layer over the reimageable surface of the imaging member 110 is presented to an inker subsystem 140. The inker subsystem 140 is used to apply a uniform layer of ink over the layer of dampening solution and the reimageable surface layer of the imaging member 110. The inker subsystem 140 may use an anilox roller to meter an ink onto one or more ink forming rollers that are in contact with the reimageable surface layer of the imaging member 110. Separately, the inker subsystem 140 may include other traditional elements such as a series of metering rollers to provide a precise feed rate of ink to the reimageable surface. The inker subsystem 140 may deposit the ink to the pockets representing the imaged portions of the reimageable surface, while ink deposited on the unformatted portions of the dampening solution will not adhere based on the hydrophobic and/or oleophobic nature of those portions.
A cohesiveness and viscosity of the ink residing in the reimageable layer of the imaging member 110 may be modified by a number of mechanisms. One such mechanism may involve the use of a rheology (complex viscoelastic modulus) control subsystem 150. The rheology control system 150 may form a partial crosslinking core of the ink on the reimageable surface to, for example, increase ink cohesive strength relative to the reimageable surface layer. Curing mechanisms may include optical or photo curing, heat curing, drying, or various forms of chemical curing. Cooling may be used to modify rheology as well via multiple physical cooling mechanisms, as well as via chemical cooling.
The ink is then transferred from the reimageable surface of the imaging member 110 to a substrate of image receiving medium 114 using a transfer subsystem 160. The transfer occurs as the substrate 114 is passed through a transfer nip 112 between the imaging member 110 and an impression roller 118 such that the ink within the voids of the reimageable surface of the imaging member 110 is brought into physical contact with the substrate 114. With the adhesion of the ink having been modified by the rheology control system 150, modified adhesion of the ink causes the ink to adhere to the substrate 114 and to separate from the reimageable surface of the imaging member 110. Careful control of the temperature and pressure conditions at the transfer nip 112 may allow transfer efficiencies for the ink from the reimageable surface of the imaging member 110 to the substrate 114 to exceed 95%. While it is possible that some dampening solution may also wet substrate 114, the volume of such a dampening solution will be minimal, and will rapidly evaporate or be absorbed by the substrate 114.
In certain offset lithographic systems, it should be recognized that an offset roller, not shown in FIG. 1, may first receive the inked image pattern and then transfer the inked image pattern to a substrate according to a known indirect transfer method using an offset roller, or other device, as an intermediate transfer body.
Following the transfer of the majority (95+%) of the ink to the substrate 114 at the transfer nip 112, any residual ink and/or residual dampening solution must be removed from the reimageable surface of the imaging member 110 to prepare the reimageable surface to repeat the digital image forming operation without "ghosting." This removal is most preferably undertaken without scraping or wearing the reimageable surface of the imaging member 110. An air knife or other like non-contact device may be employed to remove residual products. It is anticipated, however, that some amount of ink residue may remain. Removal of such remaining ink residue may be accomplished through use of some form of active cleaning subsystem 170. The 212 Publication describes details of such a cleaning subsystem 170 including at least a first cleaning member such as a sticky or tacky member in physical contact with the reimageable surface of the imaging member 110, the sticky or tacky member removing residual ink and any remaining small amounts of surfactant compounds of the dampening solution from the reimageable surface of the imaging member 110. The sticky or tacky member may then be brought into contact with a smooth roller to which the residual ink and other products may be transferred from the sticky or tacky member, the ink and other products being subsequently stripped from the smooth roller by, for example, a doctor blade or other like device and collected as waste.
The 212 Publication details other mechanisms by which cleaning of the reimageable surface of the imaging member 110 may be facilitated. Regardless of the cleaning mechanism, however, cleaning of the residual ink and dampening solution from the reimageable surface of the imaging member 110 is essential to preventing ghosting in subsequent image forming operations as the images change. Once cleaned, the reimageable surface of the imaging member 110 is again presented to the dampening solution subsystem 120 by which a fresh layer of dampening solution is supplied to the reimageable surface of the imaging member 110, and the process is repeated.

Systems and methods for implementing a release film for a cleaning unit in an image forming device using digital offset lithographic printing techniques


A service apparatus for servicing an ink jet pen having a housing defining an ink reservoir and including a print head connected to the housing in communication with the reservoir. The apparatus includes an elongated probe having first and second passages, a fluid supply conduit in communication with the first passage, a drain conduit in communication with the second passage, a fluid receptacle separate from the probe, and a vacuum source in communication with the receptacle. The apparatus may be operated by connecting a pen to the fluid conduit to provide fluid communication between the conduit and the reservoir, draining ink from the reservoir through the fluid conduit, generating a flow of rinse fluid into the reservoir, draining the rinse fluid from the reservoir; and expelling ink through the print head.

Ink jet printers employ ink jet pens for generating an image on printer media. Pens normally include a housing defining a chamber filled with liquid ink, and a print head attached to the housing in communication with the chamber. The print head has a multitude of independently addressable orifices for expelling small droplets of ink onto the media. If one of the orifices should become clogged by a particle from within the chamber, the pen is considered to have failed. Such failures may be analyzed to determine the source of the contaminant particle, providing an opportunity to address a possible source of contamination introduced during pen manufacturing. Conventional failure analysis techniques have required aggressive measures to dismantle failed ink jet pens. A passage for draining ink must be formed, typically by cutting away a housing seal with a knife. Then, the ball cork must be pressed into the pen. A vent hole is created in the pen housing with a soldering iron to relieve the vacuum that would be generated as ink drains. The vent hole size is critical, as it must be large enough to admit sufficient air, yet not so large as to damage the ink-containing reservoir inside the housing. Such a process requires repeated cleaning and purging of a drain tube and a vent tube to reduce unwanted ink spillage. Also, the use of sharp or heated tools presents safety risks to personnel.
These disadvantages are overcome or reduced by providing a service apparatus for servicing an ink jet pen having a housing defining an ink reservoir and including a print head connected to the housing in communication with the reservoir. The apparatus includes an elongated probe having first and second passages, a fluid supply conduit in communication with the first passage, a drain conduit in communication with the second passage, a fluid receptacle separate from the probe, and a vacuum source in communication with the receptacle. The apparatus may be operated by connecting a pen to the fluid conduit to provide fluid communication between the conduit and the reservoir, draining ink from the reservoir through the fluid conduit, generating a flow of rinse fluid into the reservoir, draining the rinse fluid from the reservoir; and expelling ink through the print head.

Fluid purge apparatus and method for ink jet printer pen


A rolling bearing, wherein the rolling elements are loaded, equipped with a cage separating the rolling elements, wherein at least one groove is situated on the bearing race on which the rolling elements travel, wherein edges of the groove are positioned at an angle α from 4.5° to 80° in relation to the movement direction of the rolling elements, and in the cage, holes for the rolling elements are made askew so that the angle β between a straight line connecting the cage centre with the centre of the hole for the rolling element and a tangent to the rolling element in the contact point of this element with the cage has a value β>arc tg μ, where μ is the sliding friction coefficient of mating of the rolling element material with the cage material.

Rolling bearings used as structural components of machine parts are known. Designs of rolling bearings are diversified—however, in every case, they contain rolling elements, moving between two bearing races. Additional components of a rolling bearing may include: separators (cages) maintaining the rolling elements in a constant mutual distance, sealing elements etc.
Rolling bearings provide a rotary motion of a shaft and maintaining a constant position of its rotation axis, also, they transmit loads, so they should be characterised by low resistance to motion, stable operation, reliability of operation, and wear resistance, or high durability. To obtain the lowest possible energy losses due to friction and reduction of noise resulting from vibrations of mating components, the bearing races of structural components which mate with the rolling elements are ground, and then superfinished. However, small differences of dimensions of the rolling elements cause an important problem. The mass-produced rolling elements are classified in regard to their sizes, but achieving an absolute dimensional uniformity of the rolling elements is impossible in practice. For example, balls with diameters differing by up to 2 μm are inserted into a ball bearing. In a so-assembled bearing, which rotates e.g. with a rate of 1000 rpm, the individual balls moving on the races may cover distances differing by even 20 mm during 1 minute of operation. Unequal loads of the rolling elements of the bearing causes further differences in the distance covered by a rolling element. In the rolling bearings transmitting only transverse loads, the rolling elements which do not transmit any load are moving, which equalises the distance covered. In the bearings, where all rolling elements are loaded, the equalisation of the distance covered by the rolling elements takes place due to a spin of the rolling element in relation to the bearing races. For the spin to occur, the forces of a ball acting onto a cage or a neighbouring ball must increase to values exceeding the sliding friction forces. The higher the load of the bearing, the higher the sliding friction forces. In such a case, a grease used for greasing of rolling bearings is a necessary factor which ensures a correct mating. Lack of a proper greasing is the main factor of the bearing's wear. Rolling bearings transmitting only transverse loads, having cages made of materials with a low friction coefficient, may work without greasing.
The description of an international Patent Application No. WO2011105919 discloses a bearing consisting of two rings equipped with bearing races, on which loaded rolling elements travel, wherein at least one groove or recess positioned transversely towards the movement direction of the rolling elements is situated on one of the bearing races. The transverse groove or recess allow the rolling element for a momentary unmating with one of the bearing races, and moving, under the influence of the cage force or a neighbouring rolling element force, due to different diameters of the rolling elements and unequal load of the rolling elements of the bearing. A lack of the slide between the rolling element and the races, resulting from the use of a bearing according to the invention with a transverse unfilled groove or recess, enables operation of the bearing without greasing.
Bearings with grooves, particularly transverse grooves, or with indentations or recesses in the bearing races, are also presented in the following patent descriptions: EP375938, US20080285903, U.S. Pat. No. 1,334,027, JPH07197937.


An X-ray computed tomography apparatus includes a substantially annular frame, a mechanism configured to support rotatably the frame, an X-ray tube mounted on the frame, an X-ray detector mounted on the frame, a position detecting unit configured to detect that the frame passes a reference position, a counting unit configured to count the cumulative number of revolutions of the frame on the basis of an output from the position detecting unit, and a storage unit configured to store data of the cumulative number of revolutions of the frame.

1. Field of the Invention
The present invention relates to an X-ray computed tomography apparatus of a type in which an X-ray tube rotate around a subject to be examined.
2. Description of the Related Art
Conventionally, an X-ray computed tomography apparatus has been widely used to take a tomographic image of a subject to be examined. The mainstream of current X-ray computed tomography apparatuses is a type in which an X-ray tube and X-ray detector continuously rotate around a subject to be examined.
A gantry incorporates a motor which rotates/drives an annular rotating frame (support) on which an X-ray tube and X-ray detector are mounted. With this arrangement, the X-ray tube and X-ray detector serve to detect transmitted X-rays while applying X-rays to a subject to be examined from various directions, and the X-ray computed tomography apparatus reconstructs a tomographic image of the subject on the basis of the detected data. The gantry is provided inside with a slip ring and brush for, for example, supplying power to the X-ray tube, the X-ray detector, and the like which rotate, and extracting various kinds of signals (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 8-280661), a bearing (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 5-305075), a pulley and belt for transmitting the power generated by the motor (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-112995), and the like.
In general, the gantry is provided with a tilting mechanism which tilts the frame so as to change the slice angle of scan with respect to a subject to be examined (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2003-52689). This tilting mechanism comprises a monitor, rollers, sprockets, chains, and the like as disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 5-91995.
A couch is provided with a driving means for driving a top in the vertical and horizontal directions, as disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2003-126083. The power generated by this driving means is transmitted to the top through pulleys, belts, and the like.
As described above, various kinds of consumable parts and parts that require cleaning, such as slip rings, brushes, bearings, pulleys, belts, rollers, sprockets, and chains, are used for an X-ray computed tomography apparatus. In order to maintain the apparatus in a proper state, it is important to perform maintenance such as cleaning and inspection of the apparatus and replacement of consumable parts at proper timings.
The maintenance of an X-ray computed tomography apparatus has often been performed in a cleaning cycle, inspection cycle, and part replacement cycle set on the basis of reference data created by a maker or the like. In this case, reference data is data concerning the durability of parts and the like, which is created by a maker or the like for, for example, the calculation of the lifetime of an apparatus. This reference data is generally created on the basis of an inspection method unique to each maker, load values, and the like. Such inspection methods have not been unified. For example, in some cases, inspection is done by applying an actual load to an apparatus after a target part is built in it. In other cases, inspection is done while a given standard load value is applied to an apparatus.
According to such a conventional maintenance service, maintenance is performed in a uniform cycle in every hospital regardless of the frequency of use of an X-ray computed tomography apparatus in the hospital. Therefore, the following problems may arise. With regard to an X-ray computed tomography apparatus with a high frequency of use, since a given part greatly wears out in the same period, a proper maintenance timing may be lost. If the apparatus fails due to this, it cannot be used during a repair period. This causes inconvenience to the user. With regard to an X-ray computed tomography apparatus with a low frequency of use, since a given part wears out little in the same period, maintenance may be done before a proper maintenance timing, inflicting unnecessary cost on the user.
As described above, a maintenance timing has been set on the basis of the use period of an X-ray computed tomography apparatus. However, a maintenance timing should be determined on the basis of the frequency of use of the apparatus and, more specifically, the actual operation amount of each part constituting a driving portion. For conventional X-ray computed tomography apparatuses, however, maintenance timings could not be determined on the basis of such a criterion.
In addition, in consideration of the fact that many parts used for an X-ray computed tomography apparatus are developed as parts dedicated to the apparatus, the number of parts as samples in a durability test is greatly limited (for example, about one to three) under the present situation. Therefore, the reliability of reference data is not necessarily high. For example, makers and the like have prevented the occurrence of problems in apparatuses by setting relatively short maintenance cycles. In some cases, a technician of an X-ray computed tomography apparatus designates a maintenance timing on the basis of his/her experience at his/her own discretion. The validity of the maintenance timing is inevitably questionable.
Performing maintenance at the timing based on such data with low reliability and validity will lead to the waste of service provision time and labor on the customer engineer side, and will lead to the waste of cost and the risk of apparatus failure on the user side.