Pulsed, coherent light is generated by optical mixing which takes place inside the resonator of a pulsed laser oscillator. One of the beams to be mixed is generated by the pulsed laser, and the other by a distinct, external laser oscillator. If the light from the external oscillator is modulated, that modulation will be transferred onto the light generated by the optical mixing. Using sum frequency generation, light for sodium excitation, such as for a guide star, can be generated with the optimal modulation of spectral and temporal properties. If the pulse repetition frequency is chosen to be at or near the magnetic (Larmor) resonance of the sodium, then the amount of scattered light due to sodium excitation is enhanced, and the magnetic field at the location of the sodium atoms can be measured.

In this document, I will use the word "light" interchangeably with "optical radiation," understanding that a range of invisible wavelengths which propagate similarly to light are included when either term is used.
The most common techniques for generating coherent light involve laser action. Laser action occurs when atoms or molecules in their excited state generate and amplify light at a specific wavelength determined by the energy difference between the excited state and the unexcited state of the atom or molecule. There is a limited set of wavelengths at which coherent light can be efficiently, reliably, and economically generated using direct laser action. Laser oscillators make use of laser gain and feedback to generate coherent light, and as a general rule do not need coherent light as an input.
A set of techniques known collectively as "nonlinear optics" make use of "optical mixing" to generate coherent light, using coherent light as an input. The light generated by optical mixing may be at a different wavelength from the input, or at the same wavelength but with amplified power. This expands the set of wavelengths at which coherent light can be generated and amplified beyond the set provided by laser action by itself. A widely used type of optical mixing is second harmonic generation, also known as frequency doubling, in which coherent light is generated at an optical frequency twice the optical frequency of the input. The wavelength of the output light produced by second harmonic generation is one-half the wavelength of the input light. This can be understood by considering the relationship between optical frequency and wavelength, which states that the product of the optical frequency and the wavelength is the invariant speed of light, according to the equationc=λv   (Eq. 1)where c is the speed of light, λ is the wavelength, and v is the optical frequency.
In this document I will sometimes specify light by its wavelength, and sometimes by its optical frequency. Since the product of these two is the invariant speed of light, the specification of one specifies the other, and vice versa.
A type of optical mixing closely related to second harmonic generation is known as sum frequency generation. In sum frequency generation, the optical frequency of the generated light is at the sum of the optical frequencies of the two inputs, according to the equationv3=v1+v2   (Eq. 2)where v3 is the newly generated output optical frequency, and v1 and v2 are the two input optical frequencies. Second harmonic generation can be seen to be a special case of sum frequency generation, for the case of the two inputs being the same, that is to say, for the case of v1=v2.
An equation relating the wavelength of light generated by sum frequency generation to the wavelengths of the inputs, derived by combining Eqs. 1 and 2, is:1/λ3=1/λ1+1/λ2   (Eq. 3)where λ3 is the newly generated output wavelength, and λ1 and λ2 are the two input wavelengths.
Another type of optical mixing is difference frequency generation, in which the generated light is at an optical frequency which is the difference between the optical frequencies of the two inputs. Equation 4 relates the optical frequencies involved in optical difference frequency generation, and is similar to Eq. 2, except that now v2 must be the larger of the two input optical frequencies, and v1 must be the smaller of the two input optical frequencies. The difference frequency, v3, is the newly generated output frequency.v3=v2−v1   (Eq. 4)
By combining and then simplifying Eq. 1 and Eq. 4, it can be shown that the wavelengths involved in difference frequency generation are related by the equation1/λ3=1/λ2−1/λ1   (Eq. 5)where λ2 is the shorter of the two input wavelengths, λ1 is the longer input wavelength, and λ3 is the newly generated wavelength.
There is a distinction between sum frequency generation and difference frequency generation relating to which optical frequencies grow in power, and which get depleted. In sum frequency generation, the coherent light at the newly generated optical frequency v3 increases in power at the expense of both of the two inputs, at optical frequencies v1 and v2. However, for difference frequency generation, the light at the lower input frequency v1 as well as the newly generated frequency v3 increase in power, at the expense of the light at the higher input frequency v2. Thus difference frequency generation can be used both to generate a new frequency v3, found by subtracting the lower from the higher of the two input frequencies, and to amplify light at the lower input frequency v1, all at the expense of the light at the higher input frequency v2. Amplification is a form of generation, for the case where the newly generated light is at a wavelength that is already present. This process of amplification, which is inherent in difference frequency generation, is often called "optical parametric amplification." The distinction between difference frequency generation and optical parametric amplification is simply in which output beam is utilized.
Optical mixing can in principle take place in any material, but sum and difference frequency generation take place efficiently only in crystals. Thus the material in which optical mixing occurs will be referred to as a nonlinear crystal.
A good reference on these general facts of optical mixing is "Nonlinear Optics", Third Edition, by Robert W. Boyd, published by Academic Press in 2008.
A useful feature of optical mixing is that when light at one input optical frequency v1 is modulated, and the light at the other input optical frequency v2 is not modulated, then the output light at optical frequency v3 after optical mixing will have exactly the modulation of the light at the first optical frequency v1 (except for a possible change of sign.) Thus not only power can be transferred between different optical frequencies, but also modulation. The two types of modulation are phase modulation and amplitude modulation, and both are transferred from the input optical frequency to the generated optical frequency.
To say that light is not modulated is equivalent to saying that the light consists of a single optical frequency, rather than the range of optical frequencies present in all natural light and most laser light. Optical mixing with one of the inputs consisting of a single optical frequency will result in the modulation of the other input being transferred to the newly generated output. I will use the expression "single-frequency oscillation" to describe laser oscillation which produces light which for practical purposes consists of a single optical frequency. A "single-frequency laser" is a laser oscillator which produces light which for practical purposes consists of a single optical frequency.
In the simplest configuration for optical mixing, two beams of light to be optically mixed pass through a nonlinear crystal, with no feedback path in either beam. Such designs tend to be inefficient for beams of low and moderate powers, with only a small fraction of the light converted to the new optical frequency. An important feature of optical mixing is that the efficiency of the process increases with the input power, until efficiency is limited as it approaches the ideal efficiency of 100%. Thus, only at relatively high power is the optical mixing process efficient. For the robust and reliable nonlinear material lithium triborate (chemical formula LiB3O5, common name LBO), input power in excess of 1000 watts is needed to reach a good level of efficiency, such as 50% conversion. Even for less-robust nonlinear materials such as periodically poled lithium niobate (LiNbO3), which suffers from degradation when used in the visible or ultraviolet, a power of greater than 10 watts is needed in order to reach 50% efficiency.
A prior-art technique for improving efficiency is described by Dixon et. al. in U.S. Pat. No. 4,879,723, issued in 1989. In Dixon's design, the nonlinear crystal is placed inside the resonator of a laser, so that it is traversed by the internal resonant beam of the laser. One of the beams of light to be optically mixed (by sum frequency generation, in this case) is the internally circulating beam within the laser resonator. The other comes from an external source, specifically for Dixon's design, from a laser diode. This approach has two advantages. First, the internally circulating beam within the resonator has a higher power, due to the feedback within the resonator, and this higher power improves the efficiency of the optical mixing process. Second, for the beam which is resonant, light not converted in one pass through the nonlinear crystal is recycled due to the feedback of the resonator, and has additional opportunities to be converted, again raising efficiency.
For the level of power typically available from practical lasers, Dixon's design will still have low efficiency, especially when robust nonlinear materials such as LBO are used. Concentrating the laser energy into pulses would improve efficiency, since the instantaneous power can thereby be much higher than the average power, and instantaneous power is what determines the conversion efficiency of optical mixing. Roughly speaking, considering an optical mixing process with a fixed level of average power available, the efficiency can be doubled by concentrating the light into pulses with a peak instantaneous power twice the average power. With peak power ten times the average power, efficiency is increased tenfold. Of course, these efficiencies are ultimately limited as efficiency approaches 100%, but this simple rule gives a rough guide to the large enhancement to efficiency that is possible by pulsing the light to be converted.
Often, a pulsed beam is what is desired for an application, as is the case for laser radar and materials processing.
Thus both for efficiency and utility, pulsed light is desired in place of the steady, or continuous-wave, light described by Dixon.
A prior-art technique for optical parametric amplification is described by Gunnar Arisholm, Ørnulf Nordseth, and Gunnar Rustad, "Optical parametric master oscillator and power amplifier for efficient conversion of high-energy pulses with high beam quality," Optics Express, vol. 12, no. 18 (6 Sep. 2004). Though this paper describes successful efforts to achieve improved beam quality, the beam quality is "high" only in comparison with earlier optical parametric amplifiers. The beam quality parameter they achieved was M2=2.3, where a value of M2=1 is perfect, and typical lasers used for laser radar must have M2 less than 1.3. When beams are generated by optical mixing at low efficiency, the beam quality of the output is typically as good as the beam quality of the input. When conversion efficiency gets higher, it becomes difficult to generate a beam which has good beam quality. This is due to the complex effects which take place as the input beam is significantly converted, or "depleted." Once a beam is fully depleted, back-conversion occurs—which means that the generated light is "back-converted" to the input wavelength! For a realistic beam, which is more intense on center than off-center, 100% conversion occurs on-center before the efficiency over the whole beam reaches 50%. But if you increase total beam power to improve efficiency off-center, the center back-converts, actually dropping in efficiency, and you get a beam with a dip in the center.
It would be desirable to break the connection between depletion and efficiency, and to create a design which is efficient but has low depletion, so that beam quality could be maintained.
Denman et. al., in U.S. Pat. No. 7,035,297 issued in 2006, disclosed a design for a sum-frequency generator based on resonating both of the frequencies to be summed in the same resonator, which is an external resonator instead of a laser resonator. This design is efficient, but it requires that both of the input beams be unmodulated, single-optical-frequency light. This eliminates the possibility of transferring modulation on the input beam to the output beam. Also, it requires precise matching of the light into the external resonator, creating difficult tolerances on both alignment and cavity length. Though the Denman design has been successfully used to excite mesospheric sodium atoms, as needed to produce artificial guide stars for astronomy, the lack of modulation reduces the efficiency of sodium excitation, and the challenging tolerances make the design expensive to produce.
It would be desirable to have a device which can efficiently convert pulsed, modulated light at one optical frequency to another optical frequency, while maintaining the modulation.

Internal optical mixer pulsed at larmor frequency


The claimed subject matter relates to performing quality of service management in a mobile wireless communications system. In more detail, in some wireless environments a wireless terminal can be connected to multiple access nodes by way of links, and the wireless terminal can move between various access nodes changing its points of attachment to the network, including its primary point of attachment. Requesters of resources with respect to the wireless terminal can be notified when the primary point of attachment alters, such that subsequent requests are provided to a correct access node (e.g., base station).

I. Field
The invention relates generally to communications systems, and more particularly to providing refined quality of service with respect to one or more traffic flows associated with a terminal.
II. Background
Communication networks, such as wireless communication networks, broadband networks, and any other suitable networks are utilized in connection with transferring data, wherein data can include word processing files, streaming video, multimedia files, voice data, and/or the like. Providing appropriate quality of service (QoS) to certain subscribers can be important for retaining customer satisfaction as well as optimizing resources associated with one or more network links. In wireless networks, however, providing appropriate QoS can be difficult, as QoS support must be considered in connection with units that are transitioning between different access nodes (e.g., base stations, access routers, or access points). Thus, providing appropriate QoS treatment to a wireless terminal is a nontrivial case.
In a typical wireless communications network, a set of geographically dispersed access nodes (e.g., base stations) provide wireless access to a communications infrastructure for a plurality of end nodes (e.g., wireless terminals). Cellular network systems have traditionally been primarily based on circuit-switch technology, but a variety of emerging cellular network systems are more heavily based on packet-switched technology (e.g., the Internet Protocol (IP) suite). In such networks, flexible QoS differentiation mechanisms are needed to effectively support a variety of different applications (e.g., telephony, text messaging, streaming audio/video, web browsing, file transfer, . . . ). QoS mechanisms designed primarily for use in fixed, hard-wired, packet-switched network infrastructures are not well suited for use in a cellular network. In particular, aspects such as mobility of subscriber access devices, the potentially constrained nature of a wireless access link, and differences in network architecture impede or preclude use of existing resource control protocols in wireless packet-switched networks.
In connection with requesting QoS support with respect to a particular subscriber, conventional networks utilize a centralized entity or a subscriber with respect to such requests. For instance, if a subscriber needs certain QoS support, such subscriber requests such support from a provider of QoS support. These conventional methods for requesting and receiving QoS support are inflexible and inefficient.

Provision of a move indication to a resource requester


A ureteral stent is nominally straight, but is provided with a coil adjacent one end to prevent migration. The coil portion is straightened upon insertion into the ureter on a guide wire, and is supposed to coil after insertion to prevent migration. An electronic signal is provided when such coiling does take place, and is applied to externally human descernable structure such as a meter. Various embodiments of the invention are disclosed, and may include a metallic cylinder embedded in the end of the stent and disposed adjacent a coil within the straight portion of the stent for inductive relation when the coiled portion has properly coiled following insertion.

There are various reasons why a ureter may fail totally or in part to carry urine from the kidneys to the bladder. This is a serious medical condition that may be life threatening in its implications. Procedures are known for placing a catheter or stent through the ureter from one end to the other to ensure proper carrying of urine from the kidneys to the bladder. This may be for a short term or for a very long term.
There is a tendency for a ureter catheter or stent to tend to migrate from its position in the catheter, typically from the kidneys to the bladder. This is highly undesireable, and may totally defeat the purpose of the stent. Efforts have been made to prevent such migration, and typically comprise coiling of one or both ends of the stent. A stent is inserted by a quasi-surgical procedure lengthwise from the bladder into the kidneys, and the stent must be straight for this purpose. Accordingly, a stent, which typically is made of silicone is preconditioned to a curve, but it is straightened by an inserting wire or the like. It is often very difficult to tell if the stent end has properly coiled into its premolded position after insertion and after removal of the inserting wire.


A magnetic disk assembly having a stack of magnetic disks supported by a clamp ring is disclosed. A cap is fastened to the top of a spindle hub by screws beforehand. Subsequently, a clamp ring is affixed to the cap by shrinkage fit. Even when some defects are found on a stack of disks, the defective disks can be readily removed from the spindle hub and replaced.

The present invention relates to a magnetic disk assembly for use in a data processing apparatus or similar apparatus and, more particularly, to a magnetic disk assembly having a stack of magnetic disks capable of recording a great amount of data and supported by a clamp ring.
One of conventional magnetic disk assemblies is disclosed in Japanese Patent Laid-Open Publication No. 2-292786. The disk assembly has a plurality of magnetic disks and a plurality or spacer rings alternating with each other. The spacer rings each separates the nearby disks and adjoins the inner edges of the disks. An annular groove is formed in the outer circumference of each spacer ring. A spindle hub has a flange portion at the bottom thereof. The flange portion is formed with a first annular support surface contacting the lowermost or bottom disk. A clamp ring has a second annular support surface facing the first support surface of the spindle hub and contacting the uppermost or top disk. The disks and spacer rings alternating with each other are supported by the first and second support surfaces of the spindle hub and clamp ring. The clamp ring is heated, fitted on the outer periphery of the spindle hub, and then cooled off. As a result, the clamp ring is affixed to the spindle hub in a predetermined position, thereby fastening the stack of disks and spacer rings.
However, the conventional disk assembly described above has some problems yet to be solved, as follows. The clamp ring is affixed to the spindle hub by shrinkage fit. Specifically, the clamp ring is heated to a high temperature so as to increase the inside diameter due to expansion. In this condition, it is coupled over the spindle hub and then cooled off. As a result, the inside diameter of the clamp ring is reduced due to shrinkage, fastening the clamp ring to the spindle hub. Hence, once the disks alternating with the spacer rings are affixed to the spindle hub by the clamp ring, they cannot be removed from the hub. It follows that when scratches or similar defects are found, even on part of the disks, the entire disk assembly must be replaced or discarded. This increases the production cost of the disk assembly to a critical degree.


A control platform for directing the operation of a snowblower is provided. The platform includes a bail which is pivotably moveable within the platform. Attached to and moveable with the bail are levers for controlling the engagement or disengagement of the drives that power the snowblower""s wheels and auger. Also attached with the bail are controls which permit the operator to change the speed and/or direction of the snowblower as well as the orientation of the discharge chute. Through their attachment to the bail and proximity relative to one another, an operator can use each of the levers and controls simultaneously. Accordingly, the platform permits an operator to engage or disengage the drives which power the snowblower""s wheels and auger while, simultaneously, enabling a change in speed or direction as well as the direction towards which snow is directed during the removal process.

1. Field of the Invention
This invention relates to snowblowers and more specifically to a control structure for engaging the drives to the wheels and the discharge auger and for swingably moving the discharge chute.
2. Description of Related Art
Snow removal equipment such as walk-behind snowblowers include a frame or chassis to which is mounted a pair of ground engaging drive wheels, an engine, and an auger in the form of a rotary blade for slicing and shifting snow toward a discharge chute where it is then expelled. To assist the operator in directing movement of the snowblower, there ordinarily exists a pair of curved handles which extend upwardly from the chassis. The ends of these handles have grips for the operator to hold and guide the machine as it is operated. Often, the handle and grip portion are bent straight out towards the operator. Typically, both drive wheels are driven together and are not independently powered. Accordingly, snowblowers are turned through pushing on one handlebar and holding or pulling on the other. With handles which extend at the operator, it can be difficult for the operator to exert the necessary forces required to turn the machine. This is particularly true for large machines and/or smaller operators. Thus, it would be beneficial to provide a handle that has a configuration and design which would decrease the amount of leverage needed to maneuver the snowblower.
It is common to provide snowblower controls that engage the traction drive and auger, adjust the speed and direction of the machine and orient the discharge chute at a control panel. The panel is usually secured to the handlebar(s) forwardly of the grips. Typical control levers used to engage the traction drive and/or auger are mounted to the handlebar and have an underside conforming to the shape of the handlebar. These levers pivot on the handlebar and extend upwardly from the bar when their respective auger or traction function is not engaged. To engage the auger or traction drive, an operator must press the respective lever downwardly against the handlebar and hold it there as long as engagement is desired. If the operator releases the lever, its auger or traction function will disengage.
Many times, control levers and handles for changing the speed and direction of the snowblower drive wheels, as well as the orientation of the chute through which snow is directed, are also located on the control panel. These levers and handles are placed throughout a top surface of the panel and spaced at a distance from the auger and traction controls which are used to engage the drives to the wheels and the auger. To adjust the speed or direction of the snowblower or to adjust the orientation of the chute, the operator must take one hand off the control and move it to the corresponding control for machine speed or orientation of the chute. In doing so, the drives to the wheels and/or the auger will no longer be engaged since the control levers for those drives will no longer be pressed against the handlebar. In other words, as a result of the spacing between the auger and traction levers and above-mentioned controls, an operator is unable to maintain engagement of both the snowblower""s traction drive and auger while making another adjustment such as, for example, shifting into a different operating speed.
Thus, it would be desirable to provide a configuration of controls which would allow the operator to use the snowblower with both the traction drive and auger engaged, while at the same time, allowing the ability to shift into a different speed or direction and/or change the orientation of the chute through which snow is expelled.
To address the above desire, there is provided a control platform which permits continued engagement of the traction drive and auger while allowing an operator to simultaneously adjust the machine speed and/or direction as well as the orientation of the snow discharge chute. Adjustment of the machine speed and/or direction can be made with the thumb of one hand while the orientation of the chute can be adjusted with the thumb of the other hand.
The control platform is mounted atop a handlebar framework which extends upwardly from the snowblower chassis. The platform has attached to it a bail which is pivotably moveable fore and aft within the platform. Attached to the bail is a pair of control levers, one for engaging or disengaging the traction drive and another for likewise controlling engagement and disengagement of the auger. The control for varying the speed and direction of the drive wheels, once engaged, is provided through swingably mounting the bail for fore and aft motion. To lock the speed in any of a variety of settings, there is provided a releasable pawl carried by the bail for engagement with slots in the platform to secure the bail in any of a plurality of positions as the speed or direction of the snowblower is changed. Selection of either a different speed or direction occurs when the operator engages the pawl with a particular slotted portion of the platform.
The bail with its levers and pawl are swingably coupled so as to allow the operator to control engagement of the traction drive and auger while, at the same time, allowing a change in the speed or direction of the snowblower.
Also attached to the bail is a toggle switch that controls an electrical motor which changes the orientation of the snow discharge chute and thus, the direction towards which snow is expelled from the snowblower. The toggle switch is attached to the bail and is located beside the control lever for the auger. Because of the switch location, operation of the auger and chute may occur without requiring the operator to remove his or her hand from the auger control lever since the switch is controllable by the push of a thumb. Accordingly, operation of the auger as well as manipulation of the directional movement of the discharge chute may take place simultaneously. Vertical deflection of the snow as it is discharged from the chute is achieved through use of a cap mounted on top of the chute which is controlled by a handle carried on the handlebar framework to the side of and in front of the switch.
Thus, there is provided a configuration of controls for allowing an operator to obtain simultaneous activation of the drives for the wheels and the auger while, at the same time, enabling concurrent adjustments of other controls of the snowblower""s operation. Additionally, the configuration provides a bail with ends having a downward slope in order to allow an operator to more easily grasp and control those ends by being able to exert greater leverage over them when operating the snowblower. Accordingly, the operator is able to minimize the pushing or pulling often required by previous designs, thus resulting in easier and less stressful operation of the snowblower.


The present disclosure provides a locking device for restricting access to a hatch of a pressure vessel, and, more specifically, a locking device that is responsive to the internal pressure in the pressure vessel so as to minimize the ability of one to open the hatch while the vessel is still pressurized. In some embodiments, the locking device comprises first and second portions of the locking device configurable between an open and a closed configuration and a pressure-responsive locking member in fluid communication with an outlet port of the pressure vessel and arranged to automatically retain the first and second portions in the closed configuration when the pressure inside of the pressure vessel is above a predetermined threshold, wherein in the closed configuration the first and second portions restrict manipulation of the hatch and/or a locking mechanism of the hatch.

Pressure vessels for various purposes such as abrasive blasting typically have a fill hatch which is closed and locked when the vessel is under pressure, but which can be opened to add material to the pressure vessel and/or for interior inspection and work. While such hatches typically have locking mechanisms, there can be safety concerns if the locks are prematurely disengaged while the vessel is still pressurized. The present apparatus provides an automatic safety lock responsive to internal pressure in a pressure vessel or pressurized tank to minimize the ability to prematurely open the hatch.


In wireless communications systems, a client terminal performs cell search procedure to find a suitable cell and camp on it to receive service from the network. In 3GPP LTE wireless communication system, the cell search involves the decoding of the Physical Broadcast Channel (PBCH) which may take relatively long time to decode under poor channel conditions which in turn may affect the time it takes to receive service from a cell after cell reselection or handover. A method and apparatus are disclosed that perform the PBCH decoding across multiple instances that carry partly different and partly common PBCH information. This method enables a client terminal to receive service from a cell faster than conventional methods.

As shown in FIG. 1, a wireless communication system 10 comprises elements such as a client terminal or mobile station 12 and base stations 14. Other network devices which may be employed, such as a mobile switching center, are not shown. In some wireless communication systems there may be only one base station and many client terminals while in some other communication systems such as cellular wireless communication systems there are multiple base stations and a large number of client terminals communicating with each base station. Cellular wireless communication systems with multiple base stations may be also referred to as wireless communication networks.
As illustrated, the communication path from the base station (BS) to the client terminal direction is referred to herein as the downlink (DL) and the communication path from the client terminal to the base station direction is referred to herein as the uplink (UL). In some wireless communication systems the client terminal or mobile station (MS) communicates with the BS in both DL and UL directions. For instance, this is the case in cellular telephone systems. In other wireless communication systems the client terminal communicates with the base stations in only one direction, usually the DL. This may occur in applications such as paging.
The base station to which the client terminal is communicating is referred to as the serving base station. In some wireless communication systems the serving base station is normally referred to as the serving cell. The terms base station and a cell may be used interchangeably herein. In general, the cells that are in the vicinity of the serving cell are called neighbor cells. Similarly, in some wireless communication systems a neighbor base station is normally referred to as a neighbor cell.
Client terminals used in wireless communication systems may need to search for the network, acquire the network information, camp on to the network and register for service. The aforementioned process is collectively called "network registration." The network registration process may normally take place in different scenarios that may include but are not limited to powering on the client terminal, attempting to obtain service after a loss of network coverage (e.g., a dropped call due to a "dead spot" in the network), when roaming from one network to another, etc.
The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) wireless communication system is an example of a cellular wireless communication system. In the 3GPP LTE wireless communication system, the air interface is organized into radio frames, subframes, and Orthogonal Frequency Division Multiplexing (OFDM) symbols as shown in FIG. 2, where the radio frame duration is 10 ms, the subframe duration is 1 ms and an OFDM symbol duration is about 70 μs or 85 μs depending on whether Normal Cyclic Prefix (CP) or Extended CP is used respectively. Each radio frame is numbered and identified by the System Frame Number (SFN). The SFN starts from zero and increments for each radio frame up to 1023 and then wraps around to zero and so on. Therefore, the SFN can be represented as a 10-bit number and it is incremented at the start of every radio frame.
The radio frame and subframe boundary are detected by the client terminal during the cell search procedure by first detecting the Primary Synchronization Signal (PSS) and then Secondary Synchronization Signal (SSS) as shown in FIG. 2. The PSS and SSS detection timing is relative to the internal timing of the client terminal and it is referred to herein as timing offset. The radio frame and subframe start timing is derived from the timing offsets of the detected PSS and SSS. The SSS detection requires the PSS time offset as an input from the PSS detection procedure. Therefore, the SSS detection may be scheduled after successful PSS detection. When a client terminal may not be synchronized with any of the base stations, such as in the case of initial power on, it must first find the synchronization information such as the air interface timing and frequency.
In the 3GPP LTE wireless communication system, the network may use a number of different channel bandwidths. However, the synchronization signals PSS, SSS and Physical Broadcast Channel (PBCH) are transmitted in the central 1.4 MHz as illustrated in FIG. 2 where the channel bandwidth used is 3 MHz in this example. Also, the SFN and the Physical Hybrid Automatic Repeat Request (HARM) Indicator Channel (PHICH) configuration information are required for the client terminal to receive further details about the network. The above information is transmitted by each BS in the Physical Broadcast Channel (PBCH). The payload inside the PBCH is referred as Master Information Block (MIB). The MIB is used for further processing in the client terminal for network registration. The PBCH is transmitted in subframe 0 of every radio frame in the central 1.4 MHz bandwidth of the channel as illustrated in FIG. 2.
The timing of the receive window for decoding PBCH is based on the radio frame and subframe timing detected for a given cell based on SSS detection for that cell. Therefore, the PBCH detection may be scheduled only after successful SSS detection for that cell. In the remainder of the present disclosure whenever SSS detection is scheduled it is implicit that it is preceded by a successful PSS detection. Similarly, whenever PBCH detection is scheduled it is implicit that it is preceded by a successful SSS detection.
The payload of the PBCH does not change over a period of four radio frames as shown in FIG. 3. This allows the client terminal to perform combining of the PBCH over four radio frames as shown in FIG. 4. The duration over which the PBCH payload content, i.e., MIB, remains the same is referred herein as MIB Transmission Time Interval (TTI). However, the PBCH contains the SFN in the MIB payload and the change of the SFN in payload occurs every four frames on a boundary where SFN modulo four is equal to zero as shown in FIG. 4. The SFN in the MIB contains only its upper eight most significant bits (MSBs). The two least significant bits (LSBs) of the SFN are zero for the frame where the change of the MIB content occurs. Since the client terminal is not aware of the SFN, the combining must be done over a period of seven frames while pursuing multiple parallel hypotheses as shown in FIG. 5. Each hypothesis starts at a new radio frame and corresponds to the two least significant bits of the SFN being equal to zero. Only one of the four hypotheses can be correct and in the worst case it may be the last hypothesis that may be correct. For the example illustrated in FIG. 5, the hypothesis 4 is correct as the SFN is 104, which has two least significant bits equal to zero. Therefore, the worst case time required for one complete PBCH decode attempt for one cell is seven frames (7*10=70 ms). Furthermore, if the signal conditions are poor, even after exhausting all the hypotheses, the PBCH decoding may fail. The client terminal may have to reattempt to decode the PBCH which may require another 70 ms time to pursue all the hypotheses. Although the SFN portion of the MIB may change from one TTI to another, the remaining portion of the MIB generally remains unchanged over a very long period of time such as hours to days.

Method and apparatus for broadcast channel decoder


A method of measuring the period of a vehicle speed signal is disclosed that includes the steps of accumulating predetermined time interval increments between first and second rising edges of the signal, calculating a remainder time interval upon detection of the second edge of the signal and adding the remainder to the accumulated increments value to obtain the period, and calculating an average period from a plurality of consecutive period measurements. If the accumulated value exceeds a predetermined maximum value before the second edge occurs, the maximum value is used in calculating the average.

Instrument clusters used in automobiles commonly use microprocessors to measure the vehicle speed signal and display the speed on an air-core gauge. Two common measurement techniques are used in the prior art. One, a pulse period measurement technique uses a high-resolution timer to store the time when each speed pulse edge occurs. The pulse period is the difference in 2 consecutive values. The high-resolution timer typical in current instrument clusters are 16-bits with a 2 microsecond resolution. The maximum period that can be measured without considering overflows is: EQU Max Period=$10000*2 usec=131.072 milliseconds
If overflows are considered, then the period is a relationship between the time difference and the number of overflows accumulated. An overflow is a count of how many times the timer has overflowed from $FFFF to $0000. Using an overflow counter allows longer pulse periods to be measured. Pulse period measurement has the advantages of high measurement accuracy and fast response, but exhibits a "steppy" response at low speeds and a perceived pause upon signal loss.
A second measurement technique counts the number of pulses per time interval. A timer provides a time base for counting speed pulses. Each speed pulse count is placed into a finite length buffer and periodically summed yielding a frequency. This frequency is then converted to vehicle speed. While this technique produces a smooth response over the entire range, the resolution of this method requires extensive filtering to achieve acceptable values, severely affecting the response.

Synchronous timer vehicle speed measurement


The present invention is a MILS network system employing functional separation of messages without customized switches. The MILS network system may maintain separation of data while eliminating a requirement of full message encryption. In an embodiment of the invention, a function may be employed whereby a keyed digest of a message is created. The function may receive a message and a key, and may emit a keyed digest value. The key may be representative of a particular level of security, thus promoting the separation of data. Messages may include an embedded keyed digest when sent through a switch to a MILS node. At the MILS node, the keyed digest may be recalculated, if it matches, the message may be passed to a host.

Communication networks provide the ability to transfer, retrieve and access data. A problem associated with communication networks known to the art is security. For example, conventional communication networks may be subject to interception of data. A solution for data interception is encryption whereby transferred data is encrypted prior to transport and decrypted upon retrieval of the data at the desired destination. A problem associated with encryption of data is the significant increase in overhead to the communication network.
Additionally, conventional communication systems require separate and unique hardware for transmission of data across distinct classification domains. For example, the present Fibre Channel standard architecture requires "top secret" processing, nodes, switches, graphics and secret instantiations and unclassified instantiations. Maintaining such separation in a closed computing platform causes significant overhead in components and costs because separate hardware and components are required for each classification domain.
Multiple independent levels of security (MILS) networks provide multiple levels of security for transfer of data. A MILS network is a highly assured communication system which may separate security mechanisms and concerns into manageable components. Advantageously, MILS networks may provide for secure separation of data into levels without the requirement of full message encryption. Additionally, MILS networks may reduce the number of switches, and may support additional levels of integration through a MILS real-time operating system (RTOS) while not requiring full encryption of data.
Referring to FIG. 1, a block diagram of a MILS network 100 known to the art is shown. The MILS network 100 may include a MILS switch 110, a MILS nodes 120, 130 and hosts 140, 150. Transfer of messages from host 140 to host 150 may be effectuated through nodes 120, 130 and MILS switch 110. MILS switch 110 ensures separation of data according to the classification domain. A problem associated with MILS networks 100 known to the art is the amount of customized hardware required to support the MILS computing network infrastructure. The use of customized hardware, such as MILS switch 110, increases the overall system cost and certification cost.
Consequently, a MILS network system which maintains secure separation of data and secure data transfer while reducing the requirement of customized hardware is necessary.


A method for producing a non-monocrystalline semiconductor device, such as amorphous silicon TFT, by forming at least two non-monocrystalline semiconductor films in successive manner on a substrate by plasma CVD, in which the film-growing surface and the interfaces of the formed films are constantly maintained in a plasma atmosphere until the end of film formation. In this manner the interface regions are protected from damage caused by the initial stage of plasma and eventual deposition of impurities in such regions. This is achieved, for example, by spreading the plasma area during the transfer of the substrate between the film-forming chambers.

1. Field of the Invention
The present invention relates to a method for producing a non-monocrystalline semiconductor device adapted for use in a photoelectric converting device such as a solar cell, a line sensor or an area sensor, a thin film transistor (TFT) for the liquid crystal display or the like, more particularly a non-monocrystalline semiconductor device formed by successive laminations of plural thin semiconductor films, and an apparatus for executing the method.
2. Related Background Art
Non-monocrystalline thin semiconductor films, particularly those of non-monocrystalline silicon and compounds thereof, are frequently used in photoelectric converting devices of a large area such as a solar cell or line sensor, and in thin film transistors of liquid crystal displays, such thin films can be prepared at a low temperature and show strong light absorption in the visible region.
These devices, as exemplified by the solar cells, generally have laminated structure of two or more thin semiconductor films, such as a PIN structure, in order to attain their functions. For producing such devices, there is generally an apparatus employing a load-lock system in which films can be continuously formed without breaking the vacuum state after the substrate is loaded. Such load-lock apparatus is capable of forming different layers in independent vacuum chambers, and is effective in improving the device performance in terms of impurity reduction in each layer.
For producing the non-monocrystalline thin semiconductor film, there have been utilized various methods such as plasma CVD, photo CVD, thermal CVD, sputtering, and vacuum evaporation, but plasma CVD has principally been employed since it can provide a relatively high film quality and can easily provide a film of a large area. The plasma CVD consists of film deposition on a substrate by decomposing raw material gas(es) with a high frequency field or microwaves, thereby generating a deposition precursor. Among the plasma CVD methods, most popularly utilized is the capacitance-coupled high frequency plasma CVD method employing a high frequency power of 13.56 MHz as the excitation source.
FIG. 5 is a schematic view of a conventional capacitance-coupled high frequency plasma CVD apparatus of load-lock type employed for producing a PIN device.
The apparatus 500 is provided with a loading chamber 502; an N-type layer forming chamber 503 connected to said loading chamber 502 through a first gate valve 511; an I-type layer forming chamber 504 connected to said N-layer forming chamber 503 through a second gate valve 512; a P-type layer forming chamber 505 connected to said I-layer forming chamber 503 through a third gate valve 513; and an unloading chamber 506 connected to said P-layer forming chamber 505 through a fourth gate valve 514. Thus, said apparatus 500 is a multi-chamber system with five chambers in total, in which the N-layer forming chamber 503, the I-layer forming chamber 504, and the P-layer forming chamber 505, being mutually connected through the gate valves 512, 513, are independent in terms of vacuum level.
Said capacitance-coupled high frequency plasma CVD apparatus 500 is utilized in the following manner, in the preparation of a device with PIN structure.
At first a substrate 520 is set on a substrate holder 521, which is placed on rails 507 and loaded in the loading chamber 502. The interior of the loading chamber 502 is evacuated to a predetermined pressure, and the substrate 520 is heated to a predetermined temperature. Subsequently the substrate holder 521 is transferred into the N-layer forming chamber 503 by opening the first gate valve 511, which is thereafter closed.
Then the substrate 520 is heated to a predetermined temperature by a first heater (not shown) provided in the N-layer forming chamber 503. First raw material gas 525 is introduced into the N-layer forming chamber 503, and a first high frequency source 551 is turned on to apply a high frequency power to a first high frequency electrode 541, thereby generating plasma in the N-layer forming chamber 503 and effecting the formation of an N-layer. After the completion of film formation, said first high frequency source 551 is turned off, and the introduction of first raw material gas 525 into the N-layer forming chamber 503 is terminated.
Subsequently the interior of the N-layer forming chamber 503 is evacuated, and the substrate holder 521 is transferred to the I-layer forming chamber 504 by opening the second gate valve 512. Then an I-layer is formed with second raw material gas 526, in a procedure similar to that for N-layer formation. Then the interior of the I-layer forming chamber 504 is evacuated, and the substrate holder 521 is transferred to the P-layer forming chamber 505 by opening the third gate valve 513. A P-layer is formed with third raw material gas 527, in a procedure similar to that for N-layer formation. Then the interior of the P-layer forming chamber 505 is evacuated, and the substrate holder 521 is transferred to the unloading chamber 506 by opening the fourth gate valve 514. Finally, air is introduced into the unloading chamber 506, and the substrate holder 521 is taken out from said unloading chamber 506.
The N-, I-, and P-layers can be formed in succession on the substrate 520 in the above-explained manner. Other devices can also be formed in a similar manner by suitably varying the species of raw material gases and the number of film-forming chambers.
In the capacitance-coupled high frequency plasma CVD apparatus 500, electrically grounded first to third shields 531-533 are respectively provided around the first to third high frequency electrodes 541-543, for avoiding dispersion of discharge.
However, in the film formation utilizing the above-explained plasma CVD apparatus 500, the plasma has to be interrupted between successive film formations. The present inventors have found that this creates a plasma on/off hysteresis at the interface of the semiconductor layer, eventually affecting the device characteristics.
More specifically, such plasma CVD apparatus causes plasma damage on the interface by the initial plasma. The initial plasma means the plasma generated from the moment of activation of the excitation source to the stationary state, and induces a damage in the underlying film, thus generating defects in the interface. Also the newly deposited film shows deteriorated interface characteristics, as the initially deposited part of said film, constituting the interface region, is formed by such initial plasma state. There are also reports that impurities such as oxygen, carbon, and nitrogen tend to deposit mainly at the interface, and such phenomenon results from the producing method explained above.
The device characteristics are significantly affected by such interface. For example, an amorphous silicon thin film transistor can be prepared by consecutive depositions in the order of an insulating film and an amorphous silicon film, or in the order of an amorphous silicon film and an insulating film, but the electrical properties and reliability of the device are considered generally superior in the former process. This is because the device characteristics are governed by the characteristics of the interface between the amorphous silicon and the insulating film, as the channel for the carriers is formed in a part of said amorphous silicon, close to said interface. More specifically, in the latter process, the device characteristics are deteriorated by the plasma damage induced in the surface of the amorphous silicon, constituting the channel of the thin film transistor, at the formation of insulating film on the amorphous silicon. However, even in the former process, the inherent film characteristics are not fully exploited because the channel is formed in the amorphous silicon deposited by the initial plasma.
Also in the photoelectric converting devices, the gain and the photoresponse are affected by the interface characteristics.

Method for producing non-monocrystalline semiconductor device


Provided is a composite material comprising a carrier, a conductive layer formed on the carrier, and a dielectric layer containing spacer particles formed on the conductive layer. The dielectric layer has an abrasion factor less than about 0.3 determined by a brass shim abrasion method, and a substantially uniform distribution of spacer particles substantially free of flat spots greater than about 100 microns in the x-y direction and 1500 square microns in area on any part of the surface. The spacer particles of the dielectric layer of the composite material preferably are amorphous silica. The composite material is useful in electrostatic imaging technology and provides images substantially free of defects, including artifacts or flares, dropouts and nib writing.. Also provided is a process which permits the creation of very stable dispersions of solid particles in a dispersing medium useful for both the dielectric and conductive layers of the composite material of the invention.. A white or colored conductive ground plane is also provided.

Electrostatic recording is the process of producing an image in the form of an electrostatic charge pattern on a dielectric surface and subsequently developing that latent image by toning with oppositely charged black or colored powder, usually colloidally suspended in an insulating liquid.
In a typical writing or imaging process, a writing head, which contains two or more rows of densely spaced styli and a backplate or frontplate electrode, is selectively programmed by the plotter logic to place minute dot-spaced electrostatic charges in latent image form on the recording medium. This medium is designed to receive and hold an electrostatic charge pattern. After the latent image is electronically placed on the medium, the medium is exposed to a liquid toner. Black or colored particles suspended in the toner vehicle adhere to the medium only where a previous electrostatic charge was placed. Excess toner is removed from the medium by a vacuum channel or wiper bars and the medium is then dried by forced air, thereby fixing the image to the medium. This electronically produced print is often referred to as a hardcopy.
Although various recording media have been proposed for use with electrostatic recording plotters or printers, none of them has satisfied fully the substantial need in the art, particularly for use with electrostatic recording devices such as the Benson (Oce Graphics) plotter, Versatex VS 3000 Series, 7000 Series, 8500 Series and 8500-HR Series plotters, CalComp 5700, 5800, 67000 and 68000 Series plotters and HP 7600 Series plotters. In fact, there are many deficiencies in the known products which have considerably limited their commercial utility.
Some of the main image defects which often are experienced in electrostatic recording are artifacts or flares, image breakup or dropouts and glitches. Flares are randomly occurring bursts or explosions in plotter lines due to abnormal electrostatic discharge. Dropouts are defined either as missing dots in continuous lines or in single dot patterns (half tones), or as dots missing in a specially recorded quadrant, consisting of 51 rows of 50 single dots in a row, as in a test plot performed in a CalComp 68436 color plotter. Glitches are irregular specks or non-uniform images occurring in solid dark images due to irregularities in the dielectric surface of the media.
Another defect commonly seen is mechanical and electrical nib writing which causes dark areas on the image.
Additional image problems may occur with conventional recording media because of humidity changes during use since the media is inherently moisture sensitive. This sensitivity to changes in humidity may result in repeated images or lines (ghosting) and low image density.
Various attempts to provide adequate electrostatic recording media have been made, none of which have satisfactorily solved the above problems while providing a clear, dense image.
U.S. Pat. No. 3,657,005, issued to Clevite Corporation, deals with the need to establish a controlled gap between the flat surface of a charging device and the area on the surface of the electrographic recording media where the latent image is formed. The '005 patent also specifies the frequency of the spacers per certain square area, such as 1 to 10 spacer means per 100 square rail of surface, with the spacers projecting from 0.05 to 0.4 mil above the recording media. Glass shot, starch, refractory particles and plastic particles are recommended as spacers. The simple mechanistic approach of designing a 3-D imaging space, as in '005 patent, addresses only the requirements imposed by the physics of latent charge formation on the flat surface of the dielectric materials. However, the '005 patent does not deal with humidity independent conductive layers and does not describe any composites containing carriers other than paper based media.
U.S. Pat. No. 4,752,522, issued to Mitsubishi Rayon Co., deals with the application of spacers using an insulating resin of specific volume resistivity at a narrow average particle size from 1.5 to 4 .mu.m and limiting particles of 8 microns and more in size to 0.02% by number in the distribution. The '522 patent describes the use of certain types of polymeric materials such as copolymers of acrylonitriles and styrene as the spacer particles and puts a limitation on the design of the electrostatic media both in terms of the materials to be employed and in limiting the upwards protrusion height in a range similar to U.S. Pat. No. 3,657,005. The only quality issues which are addressed are line dropouts, pen writability and image density and most of the findings in this patent are specific only to acrylonitrile-styrene copolymers used as spacers.
U.S. Pat. No. 4,795,676, issued to Oji Paper Co., deals with a composite dielectric material, including a support, that is formed of a multilayered sheet of synthetic paper and which has an electroconductive layer and a dielectric layer. The support has a surface layer formed of a thermoplastic resin film containing 0-3 wt. % of an inorganic fine powder and a paper-like layer which is made from a thermoplastic resin film containing from 8 to 65% by weight of inorganic filler (fine powder). The paper-like layers are formed on both sides of a stretched film base. The support contains no more than 50 elevations per 0.1 m.sup.2 that project upwards for 10 microns or more from the flat side of the surface layer. Despite the cumbersome structure of the composite design, image density of the hard-copy resulting from the composite of the '676 patent does not exceed 1.1-1.2 units of optical density, which is only a minimum acceptable density. Further, material produced by the '676 patent is made with a humidity sensitive conductive base and possesses all of the negative properties related to the fluctuations of the resistance of a conductive ground plane with the change of relative humidity.
U.S. Pat. No. 5,116,666, issued to Fuji Photo Film Co, deals with a composite consisting of insulating film, a conductive layer and a dielectric layer, which includes conductive fillers in the form of fibrous conductive powders.
U.S. Pat. No. 5,130,177, issued to Xerox Corp., discloses a conductive coating composition consisting of a quaternary ammonium compound deposited on one side of the paper and a dielectric coating composition on the other side of the paper. The basic objective of the '177 patent is to provide a paper suitable for electrostatic recording which has minimum curl, is less humidity dependent and is flexible. The '177 patent connects paper stiffness (flexibility) with the image quality in order to improve line dropout. However, as taught in column 12, lines 25 to 35, the surface resistivity changes from 0.11 Mohm/sq at 71% R.H. to 2.5 Mohm/sq at 24% R.H., an order of magnitude change which is totally unacceptable, for example, when opaque matte or transparent electrographic film is to be manufactured.
U.S. Pat. No. 5,192,613, issued to E. I. du Pont de Nemours and Company, introduces a humidity insensitive electroconductive layer having a conductive powder consisting of amorphous silica or a silica-containing compound surface coated with a two dimensional network of antimony-containing tin oxide crystallites. Both dielectric and conductive layers are the same cross-linked polymers, having a preferred powder to polymer ratio of about 0.6 to about 1.3. The use of polyfunctional aziridines such as PFAZ.RTM. 322 or XAMA-7, containing residual highly toxic and dangerous ethyleneimine is an undesirable feature of the design. Another disadvantage of the '613 patent is the relative hiding power of the core or shell design for conductive powders, which makes it difficult to use for the design of transparent hard copy.
U.S. Pat. No. 5,194,352, issued to Dai Nippon Printing Co., teaches a toned image of high fidelity by a contact between two films, one electrostatic and another photosensitive, positioning both of them within a boundary of a predetermined gap, and imaging the electrostatic layer via exchange exposure through the transparent photosensitive layer and then submerging the film with developed latent image into a toner. When both films are submerged into a toner, positive and negative images are obtained. Thus, the '352 patent requires two types of media, one known as media for transparent electrophotography (TEP) and the other one conventional dielectric imaging material.
U.S. Pat. No. 5,126,763, issued to Arkwright Inc., describes a multilayer polymeric film composite for use in the electrostatic recording process. It specifies a surface abrasivity of about 0.015 inch to about 0.085 inch and a surface roughness of about 30 to about 180 cc of air/minute and teaches the use of an electronically conductive layer containing at least one electronically conductive particulate in at least one polymer binder deposited beneath the dielectric layer with the specified roughness. This design has many significant deficiencies, which were discovered during intensive studies by the inventors. Among them are a gray cast of the film, an extremely excessive electrical background, when material is imaged especially, but not only, on Capricorn Plotters, as for example, CalComp 68436 series, a high level of artifacts expressed as flares, and a wider than optimal line width. Moreover, the '763 patent teaches the use of crystalline silica. The presence and use of materials known to cause lung cancer and silicosis such as crystalline silica is clearly unacceptable at the present level of medical and environmental science. Additionally, the abrasion level advocated by the '763 patent is detrimental to the state of the print head as it is gradually abraded away by hard abrasive pigments, such as crystalline silica.
Though the above patents address many questions in latent image formation, print quality and favorable interaction of media and plotter, there is still a need in the art to provide a media material which can store a highly intense latent image charge, provide a high image density after toning when Dmax is above 1.3, and provide good grounding conditions for the return of writing current to the electrical ground. A desirable media material will also employ a humidity independent conductive ground plane for opaque, matte and transparent paper, vellum, film and fabric and provide an optimized air gap for the Paschen discharge. Further desirable properties include minimization of flares and dropouts and prevention of filming, including aid in cleaning the print head of polymeric deposits and inorganic oxides. Other desirable properties include high toner adhesion, good archival characteristics and use of safe chemical compounds and procedures, avoiding noxious or smelly material, toxic chemical, carcinogenic or mutagenic compounds.
Thus, there is a need in the art to provide a high performance, high speed dielectric recording media substantially free of the disadvantages, defects and limitations of the materials disclosed in the art.
An object of the present invention is to provide a technology which utilizes unique and appropriate chemicals, compounds and procedures which will result in the manufacture of high fidelity, high resolution electrostatic imaging material.
Another object of the invention is to produce an electrostatic imaging material with smallest possible dot size, i.e., a high resolution product.
Yet another object of this invention is to produce a material which shows little or no dropouts.
Another object of the present invention is to provide a humidity insensitive transparent film of a high quality electrostatic recording.
Another object is to provide a matte film of a high quality electrostatic recording.
Another object of this invention is to provide a humidity insensitive white paper or film product for electrostatic recording of high quality.
A further object of this invention is to provide a matte film for a high quality electrostatic recording which consists of a dielectric layer, a conductive layer, a transparent polyester support and a matted antistatic coating.
An additional object of this invention is to provide low flare electrostatic recording media.
Another object of this invention is to produce a media with a diminished number of white spots. A white spot is a circular untoned area with a diameter greater than 1 mm.
Yet another object of this invention is to provide a composite for dielectric recording with high thermal stability, allowing full removal of residual solvents.
A further object of this invention is to provide a dielectric layer having low abrasion characteristics, as defined by a brass shim abrasion method, described below, as well as by the method described in U.S. Pat. No. 5,126,763, in order to provide less abrasion to the print head.
A further object of this invention is to provide a dielectric recording media of archival quality, i.e., with high resistance to scratching, excellent toner adhesion, high moisture resistance, etc.
A further object of this invention is to provide a high quality material, with a low level of electrical background, i.e., with an imperceptible nib writing level.
Still another object of the present invention is to provide a conductive ground plane which can utilize extremely low levels of dopant for the electronically conductive particulate.
Yet another object of the present invention is to provide a white ground plane which exhibits a conductivity in the range of from 1 to 10 Mohms/sq. Still another object of the present invention is to provide conductive ground planes in various colors.
Yet another object of the present invention is to provide a novel impingement process for the preparation of an electrically conductive layer wherein the electronically conductive particulate is reduced to a nanoscale size.
These and other objects of the present invention will become apparent upon review of the following specification, the drawing and the claims appended thereto.

High performance composite and conductive ground plane for electrostatic recording of information


An electroless gold plating solution comprising a gold(I) complex, a thiosulfate, a sulfite, a pH regulator and an oxidation controller. The electroless gold plating solution uses a novel reducing agent system, the thiosulfate-sulfite-sulfate system. It shows a plating rate and a plating solution stability comparable to those of conventional gold plating solutions containing borohydride, thiourea, hydrazine, and other reducing agents.

The present invention relates to an electroless gold plating solution, and more particularly, to a gold plating solution which uses a novel reducing agent system which is low in toxicity and very stable.
Many types of reducing agents have been used, as reviewed in Gold Bulletin 8 p.119-126 (1975). These have included hypophosphite, hydrazine, diethylglycine, ammonia, thiourea, borohydride, formaldehyde, dimethylamine borane, aldehyde-amine borane, unstable organogold compounds, and others. None of these baths are truly stable or commercially useful on a large scale. Most have very short effective plating lives, often in the range of hours or a few days.
Most of the most useful commercial electroless gold plating solutions contain cyanide either as a stabilizer, a main complexing agent, or both. The U.S. Pat. No. 4,863,766 is typical, in using a gold cyanide complex, another cyanide compound, and hydrazine as the reducing agent. Another bath has been disclosed which contains gold(I) potassium cyanide, potassium cyanide and a borane compound as main constituents, as disclosed in Plating, 57 (1970), pp. 914-920. This plating solution is said to allow a plating rate of 1 micrometer/hr with some stability. However, since these plating solutions contains a large amount of cyanide ions, there is a safety problem in operation of the solutions and in disposal of waste baths, rinses, and dragout.
An electroless gold plating solution not containing cyanide ions, using gold(III) chloride and hydrazine as main constituents is disclosed in U.S. Pat. No. 3,300,328. When trivalent gold ions are used, the solutions require a larger amount of reducing agent, as compared to the case of using gold(I) potassium cyanide. In addition, the electroless gold plating solution disclosed in U.S. Pat. No. 3,300,328 is so unstable that general gold precipitation occurs in the plating solution in about 2 hours, making it impossible to continue plating.
An electroless plating bath which does not use cyanide is disclosed in U.S. Pat. No. 4,880,464. They state that the purpose of the use of a large amount of cyanide ions in a conventional electroless gold plating solution is to form stable gold complex ions, and thus control the rate of precipitation of gold where a plating solution is used with a strong reducing agent. They presumed that thiosulfate ions are suitable for use as a complexing agent in place of cyanide ions. Based on the presumption, an electroless gold plating solution was prepared by selecting thiourea as a reducing agent having a strong reducing power in a neutral aqueous solution, using a thiosulfate gold(I) complex, e.g., gold(I) sodium thiosulfate as a complexing agent, and adding a stabilizer. They found that the thiourea reducing agent gave a plating rate and a plating solution stability comparable to those of conventional plating solutions containing cyanide ions and borohydride or other strong reducing agents. However, the stability, plating rate, and appearance of these solutions are much inferior to those of the present invention. Thiourea is not an ideal reducing agent, as it is a proven carcinogenic agent in laboratory animals.


The present invention describes a method of and an apparatus for including: separating magnets and corresponding target plates; separating a lower support assembly from an upper retainer assembly of a thin-wafer handling system; and inserting or removing a thin wafer from the thin-wafer handling system.

1. Field of the Invention
The present invention relates to a field of semiconductor integrated circuit manufacturing, and more specifically, to a method of handling a thin wafer during processing.
2. Discussion of Related Art
Gordon Moore originally observed in 1964 that technology innovation had led to a doubling of a density (number of transistors per unit area) of an integrated circuit (IC) chip approximately every 12 months. By 1975, the trend had stabilized to a doubling of the density about every 18 months. Over the ensuing decades, the semiconductor industry has adhered closely to a well-known Moore's Law in increasing the density of transistors for each generation of IC chips.
The IC chip includes a planar transistor that is formed in a substrate, such as a wafer. The wafer is made from a semiconductor material, such as silicon. During processing, a material may be added to, or removed from, the wafer. The material may include an insulator, such as silicon oxide, or a conductor, such as copper.
Additive processes that are used to form material, partially or completely, on the wafer include chemical vapor deposition, sputtering, electroplating, oxidation, and ion implantation.
Subtractive processes that are used to remove material, partially or completely, from the wafer include wet etching, dry etching, and chemical-mechanical polishing (CMP).
For many layers of material, photolithographic processes are used, in conjunction with the additive processes or the subtractive processes, to pattern portions of the wafer.
Maintaining an aggressive schedule required to comply with Moore's Law has resulted in a scaling down of a metal oxide semiconductor field effect transistor (MOSFET) that is used in a complementary metal-oxide-semiconductor (CMOS) circuit. The performance and reliability of the transistor have been improved by implementing many features such as semiconductor-on-insulator (SOI) substrate, selective epitaxially deposited (SED) raised source and drain, atomic layer deposited (ALD) high-k (dielectric constant) gate dielectric, metal gates, strained channel, and low-k interlevel dielectric (ILD) layers.
Many parameters of the IC chip are monitored during fabrication to ensure that the product specification for performance and reliability will be met even as the design rule becomes tighter. However, as the wafer size becomes larger, such as a diameter of 450 mm, challenges may arise in handling and transporting the wafer without incurring any damage. The difficulty may be aggravated for thin wafers that are required for die stacking, wafer stacking, 3-dimensional (3-D) packaging, and attaching thin flip chip die to thin and flexible substrates.

Method for making a magnetically coupled thin-wafer handling system


A portable cleaning device for golf clubs has a reservoir for containing cleaning fluid, a scrubbing means attached to the bottom of the reservoir and a valve means for controlling the flow of the cleaning fluid into the scrubbing means. The user can control the valve by straightening the fingers of his hand while holding the device in one hand and the golf club to be cleaned in the other.

The present invention relates to a portable device for cleaning golf clubs.
The face of most if not all golf clubs is grooved to give a golf ball a selected direction of spin when the ball is struck. Dirt, mud or grass interferes with this action and adversely affects the golfer's game.
At the present time, most golfers simply spit on the club and wipe off the dirt with a towel. U.S. Pat. No. 4,734,952 to Parchment et al. describes a small tub lined with brushes into which the head of a club can be dipped but the size of the tub and volume of cleaning fluid render the apparatus not conveniently portable other than on a golf cart.
In view of the above, there is a need for a portable cleaning device for golf clubs which can be conveniently carried by the golfer on his person or as an accessory to his bag. It is therefore an object of the present invention to provide such a device. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter.
The invention accordingly comprises the constructions hereinafter described and their equivalents, the scope of the invention being indicated by the following claims.


A microscope according to the invention comprises an aberration correcting objective lens facing a specimen and having an aberration correcting lens correcting an aberration due to an error in the thickness of a cover, a Petri dish or a slide glass; a moving amount detector detecting moving amount of the aberration correcting lens; a focusing unit moving the specimen; a driver unit driving the focusing unit; and an arithmetic unit obtaining a defocus amount based on a moving amount detected by the moving amount detector. When the aberration correcting lens is moved, the specimen is put out of focus. On the basis of a defocus amount obtained by the arithmetic unit, the driver unit drives the focusing unit so that the lens may focus on the specimen.

The present invention relates to a microscope provided with an objective lens having a function of correcting an aberration due to an error in the thickness of a cover glass or in the thickness of a member with transmittivity holding a specimen, for example, a Petri dish or a slide glass.
Recently, the main focus in the field of biology has been shifting from the conventional observation of cells to the investigation of mechanisms of information transfer between cells. This trend has highlighted the need for higher performance microscopes and objective lenses.
Generally, an objective lens used in a microscope is designed on the premise that the thickness of a plane-parallel plate such as a cover glass is constant. Accordingly, if the thickness of a cover glass etc. fluctuates greatly, outside the design tolerance, the image forming performance of the objective lens is deteriorated. This tendency is more pronounced in high-performance objective lenses that have larger numerical apertures.
Furthermore, the image forming performance of the objective lens is deteriorated by an error in the thickness of a member with transmittivity holding a specimen such as a Petri dish or a slide glass often used in the observation under an inverted microscope.
To guard against it, a so-called correcting ring-fitted objective lens has been made available which corrects the aberrations by changing a distance between a plurality of lenses mounted in an objective lens corresponding to a change in the thickness of a cover glass or in the thickness of a member with transmittivity such as a Petri dish and slide glass, as disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 5-119263 and 8-114747.
The above-mentioned publications employ a method of correcting aberrations due to an error in the thickness of a cover glass by moving along an optical axis a group of aberration correcting lenses in an objective lens.
To correct an aberration of the cover glass thickness in observation using a microscope, after a specimen comes into focus, the correcting ring of the objective lens is turned so as to improve the resolution. When the aberration is thus corrected, however, the specimen goes out of focus and so must be focused again, thus leading to the problem of much labor being required.
It is an object of the present invention to provide a microscope which can hold a specimen in focus even when an objective lens thereof is corrected in terms of aberration.
To achieve this object, the microscope according to the present invention comprises:
an aberration correcting objective lens facing a specimen and having a movable aberration correcting lens correcting an aberration due to an error in the thickness of a cover glass covering the specimen and a specimen-holding member with transmittivity holding the specimen;
a moving amount detector detecting a moving amount by which the aberration correcting lens moves along an optical axis of the aberration correcting lens;
focusing unit changing a distance between the specimen and the aberration correcting objective lens;
a driver unit driving the focusing unit; and
an arithmetic unit obtaining a defocus amount of the aberration correcting objective lens based on a moving amount detected by the moving amount detector. In such a configuration, when the aberration correcting lens has moved, the specimen is put out of focus of the aberration correcting objective lens. Then, the driver unit drives the focusing unit so as to focus the aberration correcting objective lens, based on a defocus amount obtained by the arithmetic unit.
When correcting an error in the thickness of a cover glass or thickness of a specimen-holding member with transmittivity such as a Petri dish or a slide glass, a defocus amount is obtained which is related to a moving amount of the aberration correcting lens detected by the moving amount detector. The focusing unit changes the distance between the specimen and the aberration correcting objective lens by this defocus amount. This enables proper focusing even when the aberration correcting lens is moved to correct an aberration.
Furthermore, the microscope according to the present invention comprises:
an aberration correcting objective lens facing a specimen and having a movable aberration correcting lens correcting an aberration due to an error in the thickness of a cover glass covering the specimen or a specimen-holding member with transmittivity holding the specimen;
a moving unit moving the aberration correcting lens along an optical axis of the aberration correcting lens;
a focusing unit changing a distance between the specimen and the aberration correcting objective lens;
a driver unit driving the focusing unit; and
an arithmetic unit obtaining a defocus amount of the aberration correcting objective lens based on a moving amount by which the aberration correcting lens is moved by the moving unit. In this configuration, when the aberration correcting lens is moved, the specimen is put out of focus of the aberration correcting objective lens. The driver unit then drives the focusing unit so as to properly focus the aberration correcting objective lens, based on a defocus amount obtained by the arithmetic unit.
When correcting an error in the thickness of a cover glass or the thickness of a specimen-holding member with transmittivity such as a Petri dish or a slide glass, a defocus amount is obtained which is related to a moving amount by which the aberration correcting lens is moved by the moving unit. The focusing unit changes the distance between the specimen and the aberration correcting objective lens by this defocus amount. This enables proper focusing even when the aberration correcting lens is moved to correct an aberration.
Furthermore, the microscope according to the present invention comprises:
a state placing thereon a specimen which is covered by a cover glass or held in a specimen-holding member with transmittivity;
an aberration correcting objective lens facing the above-mentioned stage and having an aberration correcting unit correcting an aberration due to an error in the thickness of the above-mentioned cover glass or specimen-holding member;
a focusing unit changing a distance between the above-mentioned stage and the above-mentioned aberration-collecting objective lens;
an optical observation system leading the light from the above-mentioned specimen that has passed through the above-mentioned aberration correcting objective lens, to form an observed image of the specimen; and
a processor section controlling the above-mentioned focusing unit so as to focus the above-mentioned aberration correcting objective lens. In this configuration, when the above-mentioned aberration correcting unit has corrected an aberration, the specimen is put out of focus of the above-mentioned aberration correcting objective lens. Then, the above-mentioned processor section controls the above-mentioned focusing unit so that the above-mentioned aberration correcting objective lens may focus on the specimen.
Defocusing occurs if the aberration correcting lens is moved to correct an error in the thickness of the cover glass or the thickness of the specimen-holding member with transmittivity such as a Petri dish or a slide glass. The microscope according to the present invention is provided with the processor section controlling the focusing unit so that the specimen may be put in focus, thus modifying a defocus due to the movement of the aberration correcting lens. By utilizing those abilities of modification of a defocus and movement of the aberration correcting lens, it is possible to find an optimal focal point and also to realize an observation state in which such an aberration has been corrected that is caused by an error in the cover glass thickness.
In the microscope according to the present invention, the above-mentioned aberration correcting objective lens has an objective lens body. The above-mentioned aberration correcting unit has an aberration correcting lens movably attached to the objective lens body. The microscope according to the present invention further comprises:
a moving unit moving the above-mentioned aberration correcting lens;
a photo-detector with a light-receiving plane detecting a light incident upon this light-receiving plane; and
an optical detector system leading onto the above-mentioned light-receiving plane of the above-mentioned photo-detector the light from the above-mentioned specimen that has passed trough the above-mentioned aberration correcting objective lens. In this configuration, the above-mentioned processor section obtains a contrast of an image of the above-mentioned specimen formed on the above-mentioned light-receiving plane from the light detected by the above-mentioned photo-detector and, based on this contrast, controls the above-mentioned moving unit and focusing unit. As a result, the above-mentioned aberration correcting objective lens is well focused on the specimen, thereby correcting an aberration of the observed image.
A defocus due to the movement of the aberration correcting lens can be modified by changing the distance between the stage and the objective lens by as much as a predetermined amount (defocus amount). In the microscope according to the present invention, the above-mentioned processor section obtains a contrast of an image of the specimen formed on the light-receiving plane. Based on this contrast, the processor section calculates, for example, a defocus amount. Based on this defocus amount, the processor section controls the moving unit and the focusing unit. As a result, an optimal focus position can be found and also an observation state can be realized in which an aberration due to an error in the cover glass thickness has been corrected.
The microscope according to the present invention further comprises:
at least one regular objective lens; and
an objective-lens selector mechanism selectively setting a first state in which the above-mentioned aberration correcting objective lens faces the above-mentioned stage and the regular objective lens is placed far away from the above-mentioned stage and a second state in which the above-mentioned aberration correcting objective lens is placed far away from the above-mentioned stage and one of the regular objective lenses faces the above-mentioned stage.
When the regular objective lens is facing the stage, the lens is focused with the aberration of an observed image as uncorrected. If the aberration correcting objective lens is facing the stage, on the other hand, the lens is focused with the aberration of the observed image as corrected.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

Microscope with aberration correcting function


Cryogenic refrigeration system employs a power driven screw compressor which delivers pressurized refrigerant gas through a closed system to expand in a screw expander to produce refrigeration. The screw expander is rotatively coupled to the compressor. The screw compressor-screw expander cryogenic system includes heat exchangers and operates on the closed Brayton cycle to produce refrigeration.

This invention is directed to a cryogenic system wherein both the compressor and expander, which operate with the cryogenic refrigerant fluid in the system, are rotary screw type machinery of the Lysholm type.
Lysholm build an early prototype of the rotary screw compressor in 1934. Some of his development work was described in the Proceedings of the Institution of Mechanical Engineers, Vol. 150, No. 1, Pages 11-16 and 4 plates 1943. One of the main features of this screw compressor is the fact that it can run without oil or other lubricant in the compression chamber. No oil is necessary because the rotors do not contact each other or the casing. The only mechanical contact is in the bearings and in the timing gears which can be located on the outside of the casing and away from the refrigerant gas flow stream. The Lysholm type rotary screw compressor has two rotors with intermeshing lobes. Within the intermesh of the lobes and housing, the compression takes place. Two helical rotors comprise the working parts of the screw compressor. The male rotor generally has four lobes and rotates 50 percent faster than the female rotor which has six flutes between which are grooves in which the lobes interengage. Other ratios of lobes to flutes are also used. The gas is compressed in the spaces between the housing, the lobes and the grooves. The lobes and the grooves are helical so that the space appears to move progressively toward the outlet end of the housing, and the space becomes progressively smaller along the length of the rotors as the rotors rotate. Thus, gas taken in the inlet port at the suction end is compressed in the space as the rotors turn and it is finally delivered at higher pressure from the outlet port at the delivery end of the housing. The inlet and outlet ports are automatically covered and uncovered by the sharped ends of the rotors as they turn.
There have been considerable development work done on the improvement of such screw compressors. Most of the patents are owned by Svenska Rotor Maskiner which devoted the pioneer effort in this art and appears to hold most of the patents. The company is located in Nacka, Sweden.
Nilsson, U.S. Pat. No. 3,245,612 and Schibbye, U.S. Pat. Nos. 3,283,996 and 3,423,017 are particularly directed to the shapes of the lands and the grooves in the rotors, but show the porting and general organization of the rotary screw compressor to show how compression and expansion are achieved in such a structure. Furthermore, this type of screw compressor is illustrated as being the compressor in refrigerator systems in U.S. Pat. Nos. 3,432,089; 3,811,291; 3,848,422 and 3,945,216. While the use of screw compressors has been recognized for refrigerator compressor service, the use of such devices as expanders has not been recognized. Furthermore it has not been previously recognized that screw compressors and expanders in the same refrigerator can efficiently run at about the same speed so that they can be coupled directly or through gearing, for speed control of the expander and for power feedback from the expander. In the refrigeration arts, it is known that it is necessary to extract work during expansion to produce refrigeration, with some refrigerant gases within some of their operating temperature ranges. In the past, piston expanders have been used, usually in smaller refrigerators, and turbo expanders have been used, usually in larger refrigerators. While the work output of such expanders is not significant in terms of total refrigerator input power, speed control of the expander is necessary. Such speed control has been difficult where the turto expander runs at very high speed. It is part of this invention that the employment of an expander coupled to and running with the compressor is feasible when screw-type equipment is used for refrigerant gas compression and expansion. This arrangement has not previously been used in refrigerators and results in equipment which is of considerably longer life so that it can be employed in locations where maintenance is impractical. Furthermore the system is of low weight to unit of refrigeration in modest sizes, and is of low power requirement per unit of refrigeration in the same modest sizes. Therefore, such a refrigerator system can be used to cool devices for a long maintenance-free life, and can be employed in locations where total weight and input power should be minimized.

Screw compressor-expander cryogenic system


The invention is directed to a method and an arrangement for checking the operability of an actuator for the air supply and especially in combination with an idle control. By a retard shift of the ignition time point, the operability of the actuator is determined when the engine speed remains essentially constant and the engine load increases.

U.S. Pat. No. 4,601,199 discloses a method and arrangement for checking the operation of an actuator in a motor vehicle. In this method and arrangement, the actuator is driven in a pregiven manner in predetermined operating states and especially during overrun operation of the internal combustion engine and a variable is detected and observed. The variable is connected indirectly to the change of the drive of the actuator. A correct function of the actuator or of the electronic system connected thereto is assumed when a pregiven relationship exists between the particular drive change and the change of the detected variable.
This procedure cannot be applied when the pregiven operating condition, that is the overrun operation, is not present for the checking operation.

Method and arrangement for checking the operation of an actuator in a motor vehicle


A film clamping and cutting device of stretch wrapping machines is revealed. A film clamping and cutting unit and a drag set used as an auxiliary are disposed on a turntable. The drag set includes a rotatable block which is connected to an assembly wheel of the film clamping and cutting unit. The rotatable block is connected to a shaft clipped in a clip space formed between a drag plate and a clip. An elastic body is assembled between the drag plate and the clip. By way of the drag plate, the clip and the elastic body, the shaft connected to the rotatable block is not released from the clip space until a film clamping and cutting rod and a clamp reach certain positions. Thus a connection rod disposed on the rotatable block drives the clamp to clip film timely so as to clamp and cut the film precisely.

1. Field of the Invention
The present invention relates to a film clamping and cutting device of stretch wrapping machines, especially to a film clamping and cutting device of stretch wrapping machines that includes a film clamping and cutting rod and a clamp. When the film clamping and cutting rod and the clamp reach certain positions, the film clamping and cutting device clamps and cuts the film precisely.
2. Description of Related Art
Refer to Taiwanese Pat. Pub. App. No. M398517, a drag set of a film clamping and cutting device of stretch wrapping machines is revealed. In order to make the movement of a shaft of a rotatable block that drives a clamp to open and close and together with the movement of a drag plate of the drag set become smoother, a bottom edge of the drag plate is a curved sliding surface. The shaft of the rotatable block is against the curved sliding surface directly. However, when elastic fatigue of an elastic part used as an auxiliary of a drag plate occurs, the force of the drag plate acted on the shaft of the rotatable block is reduced. Thus the shaft of the rotatable block is easily sliding out from the curve sliding surface. This causes that the shaft of the rotatable block is separated from the drag plate when a film clamping and cutting rod and the clamp have not contacted and cut a film yet. Thus the clamp is closed, the film is not cut off and the residual film is not ripped off completely. Moreover, the distance between the film and objects to be wrapped is increased by a film guiding member and this is beneficial to following film cutting process performed by the film clamping and cutting rod and the clamp. However, the film guiding member including a film guiding rod and a connection rod occupies quite a lot space. The manufacturing cost is increased. These component are assembled and easily to fall off. This has negative effect on synchronous movement of the film clamping and cutting rod and the clamp.

Film clamping and cutting device of stretch wrapping machine


A process for the selective preparation of two-carbon atom oxygenated hydrocarbons, namely acetic acid, ethanol, and acetaldehyde, by continuously contacting a reaction mixture containing hydrogen and carbon monoxide with a rhodium metal catalyst, at a combination of reaction conditions correlated so as to favor the formation of a substantial proportion of these products.

This invention concerns the selective preparation of two-carbon atom oxygenated hydrocarbons, namely acetic acid, ethanol, and/or acetaldehyde, from synthesis gas. More particularly, the invention concerns reaction of synthesis gas in the presence of a heterogeneous catalyst to produce such products.
The preparation of hydrocarbons and oxygenated hydrocarbons from synthesis gas (essentially a mixture of carbon monoxide with varying amounts of carbon dioxide and hydrogen) has received extensive study and has achieved commercial adoption. Reaction conditions generally involve temperatures on the order of 150.degree.-450.degree. C., pressures of from atmospheric to about 10,000 psig, and hydrogen-to-carbon monoxide ratios in the range of 4:1 to about 1:4, with an iron group or a noble metal group hydrogenation catalyst.
One serious disability of most synthesis gas processes has been the non-selective or non-specific nature of the product distribution. Catalysts which possess acceptable activity generally tend to give a wide spectrum of products--hydrocarbons and oxygenated hydrocarbons--having a broad distribution of carbon atom contents. This not only complicates the recovery of desired products, but results in the wastage of reactants to commercially uninteresting byproducts.

Process for producing acetic acid, ethanol, and acetaldehyde from synthesis gas