The invention is directed to efficient methods for depositing highly adherent anti-microbial materials onto a wide range of surfaces. A controlled cathodic arc process is described, which results in enhanced adhesion of silver oxide to polymers and other surfaces, such as surfaces of medical devices. Deposition of anti-microbial materials directly onto the substrates is possible in a cost-effective manner that maintains high anti-microbial activity over several weeks when the coated devices are employed in vivo.

The germicidal properties of metals such as silver, zinc, niobium, tantalum, hafnium, zirconium, titanium, chromium, nickel, copper, platinum and gold are well documented. Of these metals, silver, in the form of ions or compounds, is probably the best known and most widely used anti-microbial metal. Elemental silver has some anti-microbial benefit, but is generally too unreactive for most anti-microbial applications. An oxidized form of silver is considered to be more active as an anti-microbial as indicated by the observation that painting and inking of silver oxides leads to a decrease in their reactivity and solubility.
Attempts have been made to improve the reactivity of silver through the use of silver oxides and combinations of silver with other materials using accepted methods of solution-based chemistry. U.S. Pat. No. 4,828,832 describes the use of metallic silver salt solutions such as aqueous silver nitrate in combination with an oxidizing agent, such as benzoyl peroxide, to treat skin infections.
U.S. Pat. No. 5,824,267 discloses imbedding the surface of a plastic article with silver metal particles and ceramic or base metal particles to impart antibacterial properties to the plastic article. The extremely fine silver metal particles are obtained by chemical deposition from an aqueous silver salt solution.
Although solution methods of generating silver particles are able to provide anti-microbially active silver, there is little control over the structure of the resulting silver particles, so that these methods are limited in their applications. Moreover, some ionic species, such as aqueous silver nitrate, are too reactive for most applications because of the potential for skin irritation and must therefore be carefully monitored and controlled. Another problem with solution-based chemistry is the development of stable combinations without generating harmful byproducts. Silver ions bound in solutions of pastes, paints, polymers or gels tend to have a short shelf life, in part because of the side reactions with various constituents that can occur in water-based solutions.
There is a distinct need for anti-microbial surfaces that are capable of generating a sustained release of anti-microbial metal ions. The ability of a surface to generate a sustained release of anti-microbial ions would be particularly useful in surgical and wound dressings and bandages, surgical sutures, catheters and other medical devices, implants, prosthetics, dental applications and tissue regeneration. Other devices that would also benefit from a sustained release of anti-microbial materials include medical tools and surfaces, restaurant surfaces, face masks, clothing, door knobs and other fixtures, swimming pools, hot tubs, drinking water filters, cooling systems, porous hydrophilic materials, humidifiers and air handling systems.
A method for generating a sustained release of metallic ions is described in U.S. Pat. No. 4,886,505. According to the method, a device is coated with a first metal, such as silver, and a second metal, such as platinum, which is connected to the first metal through a switch. The presence of the silver and platinum metals in the presence of body fluids results in a galvanic action which is intended to release or liberate silver ions. The release of ions is controlled by the switch, which is operated external to the device.
The technique of applying a current to a silver-coated wound dressing or medical device is also the subject matter of U.S. Pat. Nos. 4,219,125 and 4,411,648. Although the use of external switch controls or an external electric current can enhance the rate of metal ion release, such external controls or currents-may not be practical for a variety of applications.
U.S. Pat. No. 6,365,220 describes a process for producing an anti-microbial surface that provides a sustained a release of anti-microbial ions without the need for an external electric current to maintain the release. According to the disclosure, multiple layers of metallic thin films are deposited on a substrate using a sputtering or evaporation processes. By using different metal combinations for the different layers, and employing etching techniques to roughen or texture the surface of the layers, multiple microlayer interfaces can be generated. The multiple interfaces, when exposed to body fluids, provide for release of ions by galvanic and non-galvanic action.
U.S. Pat. No. 5,837,275 also discloses anti-microbial coatings that provide a sustained release of anti-microbial ions. Coatings are prepared by a sputter technique using specific deposition parameters. The coatings are described as metal films exhibiting "atomic disorder" which is claimed to be required for sustained release of metallic ions.
Single ordered crystals of tetrasilver tetroxide (Ag4O4) are claimed to be useful as an anti-microbial in treating skin diseases (U.S. Pat. No. 6,258,385.) Such a composition, however, is not practical for other than topical use, and its ability to provide a sustained release of anti-microbial materials over a long period of time (i.e. several days) without reapplication, has not been demonstrated.
Deposition of anti-microbial materials is commonly limited to one of three distinct methods for producing silver and silver oxide coatings. Each of these methods has serious disadvantages and none have been developed to efficiently produce highly adherent, evenly distributed anti-microbial films on surfaces of medical devices and instruments. Commonly used state of the art processes, such as sputtering, dip and Ion Beam Assisted Deposition, produce coatings with limited adhesion to flexible substrates or elastic devices. Additional layers to increase adhesion are sometimes necessary at a significant cost in processing time.
Deposition of metal materials on a substrate by cathodic arc in a vacuum is known in the art. In contrast to other plasma vapor deposition methods, ion plasma deposition (IPD) can produce dense multi-component coatings of high purity as described in U.S. Patent Application Pub. No. 2004/0185182. However conventional cathodic arc deposition methods suffer from certain disadvantages. A waste of expensive material can occur due to inefficient use of the target material and the lack of particle control. The lack of control over the material being deposited can result in the formation of particles of varying sizes, which leads to the deposition of non-uniform coatings. Typically the cathodic arc processes also require the substrate surface to be heated to very high temperatures, which can damage the substrate material and severely restrict the choice of substrates.


Provided is an organic electroluminescent device which has a high efficiency and high durability. The organic electroluminescent device includes an anode and a cathode; and a layer including an organic compound interposed between the anode and the cathode, in which the layer includes a phosphorescent material including an Ir complex or Pt complex having at least one ligand represented by any one of the following general formulae (1) to (4):

1. Field of the Invention
The present invention relates to a phosphorescent material, and an organic electroluminescent device and an image display apparatus using the phosphorescent material.
2. Description of the Related Art
In an old example of an electroluminescent device, a voltage has been applied to an anthracene evaporated film to emit light (Thin Solid Films, 94, 171 (1982)). In recent years, it has been known that the area of the organic electroluminescent device among electroluminescent devices can be increased more easily than the inorganic electroluminescent device and a novel material of the organic electroluminescent device can be easily developed to provide desired color development by using the material or a combination thereof. Further, as the organic electroluminescent device has advantages including its ability to be driven at a low voltage, application research has been vigorously conducted on the transformation of an organic electroluminescent device as an electroluminescent device having high-speed responsivity and high efficiency into a device including the development of a material for the device.
For example, Macromol. Symp. 125, 1 to 48 (1997) discusses an organic electroluminescent device in which two upper and lower layers of electrodes and an organic layer including a light-emitting layer between the electrodes are formed on a transparent substrate.
Meanwhile, in recent years, investigation has been conducted on not only a conventional system utilizing fluorescence upon transition from an excited singlet exciton to a ground state but also a system utilizing phosphorescence via an excited triplet exciton. Specific examples of an organic electroluminescent device using phosphorescence is described in each of "Improved energy transfer in electrophosphorescent device" (D. F. O'Brien et al., Applied Physics Letters Vol. 74, No. 3, p. 422 (1999)) and "Very high-efficiency green organic light-emitting devices based on electrophosphorescence" (M. A. Baldo et al., Applied Physics Letters Vol. 75, No. 1, p. 4 (1999)). In each of those documents, an organic layer having a four-layer structure has been mainly used. Such a four-layer structure includes, for example, a hole-transporting layer, a light-emitting layer, an exciton diffusion-prevention layer, and an electron-transporting layer disposed in the named order from an anode side. Further, as a phosphorescent material contained in the organic electroluminescent device having such a structure, Ir(ppy)3 is widely known.
As described above, an organic electroluminescent device has recently showed significant progress. The organic electroluminescent device is characterized in that it has a high luminance at a low applied voltage, a variety of emission wavelengths, and a high-speed responsivity and can be subjected to thickness reduction and weight reduction. The characteristic suggests the potential of the organic electroluminescent device to find use in a wide variety of applications.
However in terms of practical use, at present, an optical output with a higher luminance, or a high conversion efficiency has been demanded. In addition, there still remain a large number of problems in terms of durability such as a time-dependent change due to long-term use and degradation due to an atmospheric gas containing oxygen or due to moisture. Further, good color purity and a red emission with a high efficiency are demanded when the application of the device to a full-color display or the like is taken into consideration. However, it cannot be said that those problems have been satisfactorily solved.

Phosphorescent material, and organic electroluminescent device and image display apparatus using same


The present invention relates to multi-bit to pulse width modulated signal conversion, with extensions to digital-to-analog conversion. In particular, it has application to conversion of pulse code modulated signals, such as used in CDs and DVDs, to audio output.

The present invention relates to multi-bit to pulse width modulated signal conversion, with extensions to digital-to-analog conversion. In particular, it has application to conversion of pulse code modulated signals, such as used in CDs and DVDs, to audio output.
Many streaming media formats produce a multi-bit data stream. For instance, audio CDs typically encode music as a 16-bit pulse code modulated signal. MP3 files also may be decoded as pulse code modulated signals.
Audio fidelity depends in part on the signal to noise ratio (SNR) of the digital-to-analog (D/A) converter used. This converter may be part of a CD player, located on a sound card or included with powered speakers that are digitally driven. Manufacturers compete on the basis of the SNR achieved by their equipment. For instance, Creative Labs currently (in September 2005) advertises the Audigy Pro 4 sound card as achieving an SNR of 113 decibels in some modes.
An additional consideration in D/A conversion, or in any digital design, is simplicity. The fewer gates required to produce a high fidelity decoder, the better. Accordingly, an opportunity arises for new digital designs, especially digital designs that achieve strong signal-to-noise ratios.

Digital to analog converter calculating a difference between multiple indicators of a multi-bit input signal


An access method, a terminal device, and a base station are provided. The method includes: determining, by a terminal device at a current moment, that a preset condition for a link exception is met, and determining that the current moment is within a preconfigured time window; selecting, by the terminal device, one access resource from at least two preconfigured access resources as a target access resource; and sending, by the terminal device, an access signal to the base station by using a time-frequency resource in the target access resource.

In a wireless communications system, a terminal device needs to establish a connection to a network side device, and this procedure is generally referred to as a random access procedure. In a Long Term Evolution (LTE) system, after a radio link is interrupted, the terminal device needs to re-establish a connection through contention-based random access.
The contention-based random access includes the following four steps.
Step 1: Transmit a preamble sequence.
User equipment (UE) randomly selects one sequence from a higher layer parameter random access sequence set, and sends a random access preamble sequence (RACH Preamble) on a random access resource pre-specified by a base station.
Step 2: Random Access Response.
The UE receives, on a physical downlink shared channel (PDSCH), a random access response (RAR) delivered by the base station, and the UE determines, based on whether a response corresponding to the preamble sequence sent by the UE is received, whether random access succeeds.
Step 3: Send a Layer 2/Layer 3 Message.
The RAR received by the UE includes a temporary C-RNTI. The UE sends a random access procedure message to the base station on a physical uplink shared channel (PUSCH) specified in the RAR. The random access procedure message includes an identifier of the UE in a cell, and the identifier is used for contention resolution.
Step 4: Contention Resolution Message.
The UE receives a contention resolution message sent by the base station. If the contention resolution message includes the identifier of the UE, contention succeeds and a random access procedure is complete. If the contention resolution message does not include the identifier of the UE, contention fails and the UE needs to re-initiate random access.
It can be learned from the foregoing description that after the radio link is interrupted, a process in which the terminal device re-establishes a connection by using a contention-based random access procedure is relatively complex and requires a relatively long time.

Random access method, apparatus, system, terminal, and base station


A redundant array of independent disks (RAID) system comprises N storage arrays, wherein each of the N storage arrays comprise a target processing module and 1 to M hard disk drives, where M and N are integers greater than 1. A data processing module selectively assigns error checking and correcting (ECC) processing for data blocks to selected ones of the target processing modules in a non-overlapping manner. A switch module provides communication paths between the data processing module and the N storage arrays and between each one of the N storage arrays and others of the N storage arrays.

The Background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present disclosure.
A redundant array of independent disks (RAID) system redundantly stores data on multiple hard disks. In some RAID levels, data blocks are split and stored on different disks, which reduces data storage and retrieval latency. Multiple disks also tend to increase mean time between failures (MTBF) and increases fault tolerance.
The RAID system appears to an accessing or host device as a single logical hard disk drive. The RAID system may employ disk striping, which involves partitioning the storage space of each drive into units. The size of the units will vary depending upon the application from a sector (512 bytes) up to several megabytes. The stripes of all the disks are typically interleaved and addressed in order.
There are many types of RAID systems in addition to a non-redundant array (RAID-0). In RAID-0, striping is employed without redundancy of data. It offers the best performance but no fault-tolerance. In RAID-1, disk mirroring is used without striping and at least two drives are required to allow duplication during storage of data. Read performance is improved since either disk can be read at the same time. Write performance is the same as single disk storage. RAID-1 provides the best performance and the best fault-tolerance in a multi-user system.
In RAID-2, striping across disks is used. Some disks store error checking and correcting (ECC) information. In RAID-3, striping is used and one drive is dedicated to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. As a result, RAID-3 is best for single-user systems with long record applications.
In RAID-4, large stripes are used. Records can be read from any single drive. This allows overlapped I/O for read operations. Since write operations update the parity drive, no I/O overlapping is possible. In RAID-5, a rotating parity array is used, which addresses write limitations of RAID-4. Thus, read and write operations can be overlapped. RAID-5 stores parity information but does not use redundant data. However, the parity information can be used to reconstruct data. RAID-5 requires at least three and usually five disks for the array. RAID-5 is best for multi-user systems in which performance is not critical or which do few write operations.
RAID-6 is similar to RAID-5 except that a second parity scheme that is distributed across different drives is used. RAID-6 offers high fault- and drive-failure tolerance. In RAID-7, a real-time embedded operating system and controller are used. RAID-7 uses caching via a high-speed bus and other characteristics of a stand-alone computer.
RAID-10 combines RAID-0 and RAID-1. There are two subtypes: In RAID-0+1, data is organized as stripes across multiple disks, and then the striped disk sets are mirrored; and in RAID-1+0, the data is mirrored and the mirrors are striped.
In RAID-50 (or RAID-5+0), a series of RAID-5 groups are used. The groups are striped in RAID-0 fashion to improve RAID-5 performance without reducing data protection. In RAID-53 (or RAID-5+3), striping (in RAID-0 style) is used for RAID-3's virtual disk blocks. This offers higher performance than RAID-3 but at much higher cost.
When the host device sends a data block for storage, RAID processing is performed for the selected RAID approach. The RAID processing may include redundancy and recovery processing (such as error checking and correcting (ECC)) for the selected RAID level and/or other processing.
In one approach, a single central processing unit (CPU) receives data blocks from another device. The CPU handles all of the RAID processing including ECC. With this approach, the CPU can often rate-limit data storage since processing relating to ECC can be variable and time consuming. In other words, processing in the CPU may cause a bottleneck and increase latency. With a single CPU, the RAID construction for one data block needs to be completed before a subsequent data block can be processed.

This patent is subject to a terminal disclaimer.

File server for redundant array of independent disks (RAID) system


According to one embodiment, a stack includes first and second wiring structures and an inspection circuit. The inspection circuit includes a switching circuit having an input terminal, a drive terminal, and an output terminal electrically connected with a discharge mechanism. The inspection circuit is configured such that, in a state where a first electric connection is made in the first wiring structure and a second electric connection is made in the second wiring structure, at the time of applying charges to first and second electrodes, the charge applied to the second electrode flows to the drive terminal through the second wiring structure to bring the input terminal and the output terminal of the switching circuit into an electrically conducted state, and the charge applied to the first electrode flows to the discharge mechanism through the first wiring structure and the switching circuit.

A semiconductor circuit configured of a transistor, a storage device and the like which are formed on a semiconductor chip is connected with an electric circuit or the like outside a semiconductor device by use of a contact terminal on the front surface of the semiconductor chip. Examples of the contact terminal include a solder bump. Generally, the solder bump is formed by depositing a solder layer on a bump pad, provided on the semiconductor chip, by means of plating. At this time, it is of necessity to connect the bump pad and the solder bump in an electrically favorable manner, and the electric connection therebetween has been ensured by managing a manufacturing process for the semiconductor device. Moreover, also in a semiconductor chip having a plurality of solder bumps and a semiconductor device used for a multi-chip module formed by mutually connecting a plurality of semiconductor chips, when any of electric connections between the plurality of bump pads and solder bumps has a connection failure, the whole is judged as a failure, and hence it is of necessity to ensure electric connections between all the bump pads and solder bumps.
However, even when the manufacturing process is strictly managed, it is difficult to avoid occurrence of the connection failure that occurs with a constant probability in the process of mass-producing products.
For this reason, it is considered that the electric connection between the bump pad and the solder bump is checked by performing a visual inspection on the semiconductor chip. However, even when the solder layer is properly formed on the bump pad from a visual standpoint, they may be electrically disconnected, and it is thus difficult to ensure the electric connection by the visual inspection. Moreover, when the number of solder bumps is large, e.g., several hundred, inspection cost increases, thereby making it difficult to virtually perform the visual inspection on all the solder bumps.
It is also considered that the electric connection between the bump pad and the solder bump is checked by pressing a metal probe against the solder bump for electric connection, and activating the semiconductor circuit formed on the solder chip, to inspect an operating state of the circuit. However, pressing the probe against all the solder bumps to perform the electric inspection causes an increase in inspection cost when the number of solder bumps is large or a multi-chip module is to be inspected, thereby making it difficult to virtually carry out such an inspection. Moreover, a probe mark is left on the solder bump, which can be a new cause of failure.

Stack including inspection circuit, inspection method and inspection apparatus


An integrated heart-lung machine, which includes a blood pump having a casing of a cup-like shape interiorly defining a pump chamber at an intermediate portion thereof for pumping in and out blood from a blood inlet to a guide flange formed at opposite ends of the casing; a rotor having a rotary member securely fixed to the fore end thereof within the pump chamber and journalled in the guide flange; an artificial lung of a doughnut-like or cylindrical shape connected contiguously to a blood flow passage in the guide flange and concentrically with the rotor; a stator detachably fitted in an intermediate portion between the rotor and the artificial lung; and a pedestal base located at one side of the artificial lung and provided with a blood outlet in communication with the artificial lung. Accordingly, influent blood to the pump chamber is sent into the artificial lung through the blood passage by the pumping action of the rotor, and is refreshed by contact with air or oxygen in the lung, which is maintained in a heated state by the stator, and returned to the patient's body through the blood outlet. This arrangement permits minimizing of the length of the blood circulating passages to and through the machine and permits shortening and minimizing of the blood passages interconnecting the blood pump, artificial lung and blood filter, while preventing blood contamination and leaks as well as blood cell destruction. Easy installation and handling is also permitted in a sanitary region on a bed or on an operating table.

1. Field of the Invention
This invention relates to a heart-lung machine for pumping blood out of a patient's body for blood treatment and returning the treated blood to the patient's body.
2. Description of Prior Art
Extracorporeal circulation type heart-lung machines have been known, for example, from Japanese Patent Publication H2-12108 disclosing a heart-lung machine which is composed of a series of separably connected operating units including an artificial lung unit for refreshing blood through oxidation, and a heat exchanger unit in which heated water is circulated to maintain the blood at a predetermined temperature, and also from Japanese Laid-open Patent Application H2-41172 disclosing a heart-lung machine which has a blood treating section (i.e. an artificial lung) and a blood feed mechanism integrally incorporated into outer and inner portions of a cylindrical casing, respectively, such that blood, inflowing through an apex portion of a blood guide member of a substantially conical shape, is discharged through a blood discharge port by rotation of a rotary member for introduction into the blood treating section and then being allowed to flow out through a blood outlet on the downstream side, the blood treating section being interiorly provided with a heat exchanger for circulation of a heat exchanging medium therethrough.
In the former case where the blood pump, artificial lung and heat exchanger are connected in series as separable operating units, however, the machine involves a lengthy flow passage for the blood to be treated and necessitates providing a support stand exclusively for fixedly retaining the position of the machine body. In this connection, since it is difficult to install the machine in a sanitary region in the vicinity of a patient and since the heat exchanger unit needs a separate heat source, difficulties are often encountered in reducing the volume of the blood in the feed system or the blood pumped to a marked degree, coupled with the inconvenient and troublesome job of connecting inflow and outflow tubes for the heat exchanging medium to and from the heat exchanger unit.
Further, in the latter case, blood strikes against guide blades under the influence of the centrifugal force of the pump, and, as the blood is introduced into the artificial lung at a high velocity under the guidance of the guide blades, it vigorously strikes the casing of the artificial lung at the blood inlet thereof and also against hollow yarns of the lung. It follows that the blood is susceptible to destruction of blood cells (hemolysis) due to physical stresses.


A portable screen device having a dual shaft structure is disclosed. A left and a right rotation shafts are installed to an upper rod and the center of a lower frame of a screen in the horizontal direction and are connected to a left and a right supports. The rotation shafts are engaged with each other by a single adjusting device. When the screen moved up, the elasticity of the screen is held by left and right elastic wheels such that height of the screen is maintained. A magnet and a magnetic substance contact each other and are separated from each other at the central portions of the left and right supports. Due to rotation of a rotation rod installed in the intermediate portion of the supports, the screen moves up and down. Therefore, volume and weight of the portable screen device are reduced and the stability is increased.

1. Field of the Invention
The present invention relates to a portable screen device for displaying an image projected from a projector, in particularly, to a portable screen device capable of moving a screen up and down when a screen is maintained horizontal by dual rotation shafts, maintaining the height of the screen by substituting a structure using a gas spring or a coil spring with a structure of right and left eccentric rotation shafts, having a remarkably reduced volume and weight, and increased stability.
2. Description of the Related Art
In portable screen devices, since the less a volume is the more convenient it is to carry and the lighter it is the more practical, a structure for reducing volume and weight is a very important development and goal.
As structures of a conventional portable screen device, a structure, in which a screen rolled around a spring rotation shaft is accommodated in an accommodating case, has been proposed and a structure, in which the accommodating case is installed at a certain place and a screen is pulled up or maintained at a height by a pantograph using elasticity of a coil spring or a gas spring, is already used.
As the conventional gas spring or the coil spring is used, the performance such as the quantity of gas is decreased or the elasticity of the coil spring is deteriorated. Actually, as a result of checking the screen devices returned by customers, malfunction caused by the coil spring or the gas spring accounts for more than 40 percent.
According to a movable screen device disclosed in Korean Patent Publication No. 10-2000-0017351 (Claimed Priority, Japanese Patent Application Nos. 98-234542 and 99-006345), rotation shafts of right and left arms of a pantograph are coaxially arranged by duplicating the arms at a top bar or at the lower end thereof in the front-to-rear direction to maintain their horizontality when the screen moves up and down.
The conventional movable screen device further includes a height-maintaining device for canceling the elastic force of a spring generated, when the screen moves up and down to a position, by the gas spring or the coil spring.
However, since two arms are duplicated in the front-to-rear direction about a vertical axis in the coaxial structure b, the volume of the conventional movable screen device is increased.
In addition, there is a plurality of the gas springs or the coil springs as the height-maintaining device, the conventional movable screen device is heavy and its volume is increased.
Moreover, the conventional movable screen device further includes a single lozenge-shaped member as a support assembly to form lozenge-shaped dual supports.
However, since in this movable screen device the right and the left arms are structured in the front-to-rear direction by the coaxial structure, its volume increases, and since the gas springs or the coils springs are uses as the height-maintaining device, the conventional movable screen device is also heavy and its volume increases.
Further, there is another conventional movable screen device in which a right elastic coupler and a left elastic coupler are installed to hinges for connecting the arms of the pantograph or the top bar such that the right and the left elastic couplers rotate in directions opposite to each other, plate springs installed in the rear sides of the right and the left elastic couplers to apply elastic force thereto, and a brake lever pushes the right and the left couplers. The another conventional movable screen device, like the conventional movable screen device, is identical to the conventional movable screen device in view of structuring the right and the left arm as the coaxial structure using a single shaft and has advantages capable of substituting the coil springs or the gas springs with frictional pads, spring devices, brake levers. However, the another conventional movable screen device rather increases its own weight and volume due to the additional devices such as the brake levers, the addition of elastic maintaining spring structure, and the expansion of a space necessary for operating the devices.
Moreover, according to the another conventional movable screen device, in order to fix the screen at a predetermined position, the brake levers must be released and must be locked at the predetermined position again sequentially so that the height of the screen is fixed. Thus, it is very inconvenient.

Portable screen device with dual shaft structure


A system for performing PVD of metallic nitride(s) is disclosed. The improved performance is provided by a method of increasing the partial pressures of nitrogen or other active gases near the wafer surface through initial introduction of the argon or other neutral gases alone into an ionized metal plasma PVD chamber through an upper gas inlet at or near the target, initiating the plasma in the presence of argon or other neutral gases alone, after which nitrogen or other active gases are introduced into the chamber through a lower gas inlet at or near the wafer surface to increase deposition rates and lower electrical resistivity of the deposited metallic layer. An apparatus for carrying out the invention includes a source of argon near the target surface and a source of nitrogen integral to the substrate support thereby delivering nitrogen near the substrate surface.

1. Field of the Invention
The present invention relates to integrated circuit structures. More particularly, the invention relates to a method and apparatus for depositing metallic nitride layers on a substrate using a Physical Vapor Deposition (PVD) system and technique.
2. Description of the Related Art
In the formation of integrated circuit structures, an insulating layer is formed over active devices, or over a patterned underlying metal interconnect layer, and vertical openings are then formed through this insulating layer to provide electrical communication from the upper surface of the insulating layer to the underlying active device or electrical interconnect. Such openings are then filled with an electrically conductive material to provide electrical connection between the underlying elements and conductive materials, such as a metal interconnect, subsequently formed on the surface of the insulating material. In the fabrication of both horizontal and vertical interconnects, barrier layers are typically deposited over the patterned surface of a substrate to provide a barrier to prevent diffusion between adjacent materials. Conventional barrier layers include materials such as titanium nitride (TiN), tantalum nitride and tungsten nitride. The materials have been conventionally deposited using physical vapor deposition (PVD). TiN layers, in particular, have been used between adjacent materials as barrier layers for preventing the interdiffusion of adjacent layers of materials such as silicone dioxide and aluminum, for example. The barrier layer acts to limit the diffusion between the conductive and non-conductive materials and increases the reliability of the interconnect.
A conventional physical vapor deposition (PVD) processing chamber is typically operated at a pressure of about 1-10 millitorr using an inert gas such as argon (or a mixture of gases). A target of the material to be deposited (or sputtered) such as titanium is disposed in the chamber and connected to a source of DC and/or RF power. The substrate being processed is mounted on a support member spaced from and generally parallel to the target. A glow discharge plasma is struck in the processing gas by the application of DC (or RF) power to the target, and the positive argon ions are attracted to the negatively charged target. Atoms of the target material are knocked loose or sputtered from the target due to the impact momentum of the impinging argon ions and their interaction with the target material structure or lattice. The particles of material sputtered from the target are generally neutral atoms or molecules. These particles are directed in a plurality of angles from the target surface, following a distribution of directions which varies as the cosine of the angle from the particle trajectory to an angle normal to the target surface. Consequently a limited number of atoms are sputtered from the target and travel directly vertically or normal to the surface of a substrate on which they are to be deposited.
An improved PVD deposition apparatus and process is enhanced by higher-pressure background gas and an RF (radio frequency) coil, known as an ionized metal plasma (IMP) chamber and process. The IMP process provides ionization of the neutral sputtered metallic particles between the target and the substrate by utilizing background gas at pressures in the range of about 10 to about 40 millitorr in the processing chamber. A helical coil is mounted inside the chamber between the target and the substrate support and is connected to a source of RF power. The axis of the RF coil is placed generally perpendicular to the target surface and the substrate surface. If the pressure in the chamber is, for example, about 30-40 millitorr, the internal inductively coupled coil provides a high density plasma in the region between the target and the substrate support. Sputtered target atoms become ionized and positively charged as they pass through the high density plasma region. The metal ions are attracted by the negatively biased substrate and thus travel toward the substrate in a more vertical direction than occurs in conventional PVD chambers.
With the decreasing sizes of features and increased aspect ratios, barrier materials, such as TiN, are being deposited on a substrate using an IMP Physical Vapor Deposition system having a target and RF coil made of titanium. To achieve TiN deposition, both Argon (Ar) and Nitrogen are typically introduced simultaneously into a conventional IMP chamber at or near the substrate in the bottom of the chamber. After introducing both Ar and Nitrogen into the IMP chamber, power is provided to the target and the RF coil. Thereafter, a wafer bias is provided to promote deposition of the TiN on the substrate surface.
FIG. 1, is a flow diagram illustrating a conventional titanium nitride process 200. The process 200 typically begins with a gas stabilization step 202 which comprises the simultaneous introduction of about 40 sccm Ar and about 30 sccm nitrogen gas through gas inlets at or near the bottom of the chamber. Next, a power ramp step 204 is performed where power is applied to the target and the RF coil to generate a plasma. Concurrent with the power ramp step, a pump down step 206 is performed to maintain a pressure of, for example, about 20 mTorr in the chamber. After the plasma is generated, a deposition step 208 is performed by applying a wafer bias. During this step, the concentrations of Ar and Nitrogen are tuned to about 40 and 28 sccm, respectively.
The reactive sputtering techniques described above typically result in titanium nitride build-up on the sputtered surface of the titanium target over time causing the deposition rate of titanium nitride to decrease to about one third of the typical sputtering rate. This results because titanium nitride has a lower sputtering yield than titanium. Additionally, the nitrided target results in a TiN barrier layer formed on the substrate surface which has a higher electrical resistivity. The introduction of the two gases also provides unnecessarily high partial pressures of nitrogen near the target surface resulting in nitriding of the target.
It would be valuable to provide an improved PVD apparatus and process which could significantly improve the deposition rate of a nitrided material on a substrate surface by decreasing the likelihood that the target would be nitrided in the sputtering process.

Method and apparatus for ionized plasma deposition


An object of the invention is to provide an image coding device and an image decoding device enabling a transmitting color function through irreversible coding by performing the processing to reduce the occurrence of noises at the encoder's end without using a mask image. A grayscale shift unit shifts the grayscale of a transmitting color of an original image, after which a coding unit performs irreversible coding on the image. A transmitting color judging unit judges the transmitting color of a decoded image based on luminance information alone, and an up-sampling unit restores an outline of an object faithfully without being accompanied by deterioration in resolution resulted from the sub-sampling. It is thus possible to obtain a high-quality image with fewer noises.

1. Field of the Invention
The invention relates to an image coding device and an image decoding device for compositing an object image with a background image through irreversible coding having a high compression rate, using a specific color of an image as a transmitting color.
2. Description of the Related Art
To meet the advancement of digital image processing techniques, image composition processing for compositing an input image from an image reading apparatus, such as a digital camera and a scanner, with another image to be used as a background image has been used increasingly in recent years. In a case of TV broadcasting and movies, a picture of an individual standing in front of a blue or green background is taken with a camera, then the color portion of the background in the pictured video is composited with a scene of a foreign country or the like through the use of a method called a chroma key, and a video as if the individual were in that country is thereby produced.
In the WWW browser of the Internet, an image of an outlined subject is also composited with a background image. In this case, the image composition is performed on the personal computer of the user. However, because an image to be placed on the foreground is sent from a remote server over the Internet, the image is compressed to save the transmission time. The outlined subject to be placed on the foreground is called an object and the surroundings of the object are filled with a specified transmitting color, so that the background will be visible only through the portion of the transmitting color that becomes transparent when the object and the background image are superimposed. GIF (Graphics Interchange Format) and PNG (Portable Network Graphics) are known as a standard image format that realizes the transmitting color in the above manner and comes with the WWW browser. Both of these compression methods adopt reversible compression by which an image will not change due to compression.
For a color facsimile machine, there is an optional coding method called MRC (Mixed Raster Content) that enables the image composition in the same manner as above. According to MRC, an image is divided into three layers: a fore layer, a mask layer, and a back layer, and each layer is encoded through different methods. The fore layer and the back layer are color images and the mask layer is a binary image, and which of the fore layer and the back layer is to be displayed is selected at the decoder's end.
Also, MPEG (Moving Picture Coding Experts Group)-4 used for encoding a moving image is furnished with an object-based coding function that enables the image composition in the same manner as above. According to the object-based coding, an image called an alpha plane is used separately besides an image containing an object to specify a transparent portion surrounding the object. The alpha plane includes a binary alpha plane of a binary image and a grayscale alpha plane. The grayscale alpha plane is used to specify translucence as an option, and irreversible coding is applied. The binary alpha plane is essential and reversible coding is applied.
FIG. 7 shows the original image 1 with a specified transmitting color 5, and FIG. 8 shows the decoded image 2 obtained through irreversibly coding. The reason why the related arts use the reversible coding for the image composition using a transmitting color as with GIF and PNG is as follows. That is, even when the transmitting color is specified, the pixel density is changed between a non-encoded original image 1 and a decoded image 2 in the case of irreversible coding, which causes noises particularly near the edge, and a portion other than the transmitting color portion is thereby produced in the surroundings of an object 4. Both in FIG. 7 and in FIG. 8, the gray portion represents the transmitting color. The reversible coding, however, has a problem that a compression rate is lower than that of the irreversible coding.
In order to use the irreversible coding while avoiding the occurrence of noises 6 in the surroundings of the object 4, a mask image is used separately besides the images to be composited as with the arbitrary shape coding in MRC and MPEG-4. Of a mask image 3 of FIG. 9, a white portion specifies the display of an object and a black portion specifies the display of a background. However, although a mask image is a binary image, it has to be reversibly encoded, which increases an overall coding quantity. Moreover, the need to composite images at the decoder's end using two or more coding methods not only complicates the device, but also demands a larger memory capacity, thereby posing a problem that the manufacturing costs are increased.
Further, in many cases of irreversible coding, an image is separated into a luminance component and two color-difference components before being encoded, and sub-sampling is performed on the color-difference components. This is because the human eyes are less sensitive to a change in color difference in comparison with a spatial change in luminance. Thus, in the case of a natural image, when an individual sees an image restored to the original resolution through up-sampling at the time of decoding, he hardly notices deterioration in image quality; moreover, it is almost impossible to identify a difference between an image restored from the data on which the sub-sampling was performed and an image restored from the data on which the sub-sampling was not performed. The occurrence of noises can be suppressed by lowering the compression rate even in the irreversible coding method. However, because the resolution is deteriorated when the sub-sampling is performed, lowering the compression rate is not suitable when displaying characters, the shape of an object, etc.

Image coding device, and image decoding device using irreversable coding without mask image


An n bit D/A decoder is formed using P-type and N-type transistor switches, instead of convention CMOS switches. Each P-type and N-type switch may be formed of fewer transistors than those used to form a CMOS switch, thereby reducing the overall transistor count. The decoder may be used to decode digital values to non-linear GAMMA corrected analog output voltages.

D/A converters/decoders have a wide variety of applications in modern electronics. Typically, a D/A converter provides an analog output corresponding to a digital input.
Display elements in modern displays, for example, are formed as two dimensional arrays of emissive elements, typically in the form of liquid crystals, light emitting diodes (LEDs), organic light emitting diodes (OLEDs), plasma cells or the like, surface conduction electrode-emitter displays (SEDs). Emissive elements are arranged in a two-dimensional array. Each element represents one pixel in the array, and may include one or more active components. For example color liquid crystal displays (LCDs) typically include at least three crystals per pixel, with each crystal representing one color component of the pixel. The three crystals, in combination with back lighting form the emissive element that can be used to display a pixel of arbitrary color.
As each display is made of a multitude of individual display elements, suitable drive circuitry is required. As each display element is typically formed with three color emitting components, the drive circuitry typically includes three separate driver elements for each pixel. Drive circuitry typically includes multiple D/A converters, each of which includes a digital decoder used to output suitable analog drive voltages or currents to drive the individual display elements. Typical D/A decoders are formed using a multitude of transistor switches to provide output analog voltages selected in dependence on a digital value to be decoded. One such design uses a complementary metal oxide semiconductor (CMOS) switches, requiring at least two transistors per switch.
As newer displays are significantly thinner and lighter than conventional CRT displays, they may be miniaturized and form part of a variety of electronic devices including televisions, computer monitors, and easily portable devices such as digital media players, mobile phones, personal digital assistants, MP3 players, and the like. In such devices reducing transistor count is desirable, as reduced transistor counts reduce power consumption.
More generally, integrated circuits and functional blocks of such integrated circuits with fewer transistors may be manufactured to consume less power and occupy less space.
Accordingly, a digital to analog decoder having fewer electronic components is desirable.

Reduced component digital to analog decoder and method


A method for improved operation of a natural gas liquids stabilizer column, particularly a small-scale, is provided. The method can include the steps of: introducing a first feed stream comprising heavy hydrocarbons and natural gas to a stabilizer column to produce a top gas and a bottoms liquid, wherein the top gas has a higher concentration of natural gas as compared to the first feed stream, and the bottoms liquid has a higher concentration of heavy hydrocarbons as compared to the first feed stream; introducing a second feed stream into the stabilizer column, wherein the second feed stream has a higher concentration of natural gas as compared to the first feed stream, wherein the second feed stream is at a warmer temperature than the first feed stream when introduced into the stabilizer column, wherein the second feed stream is a gaseous stream; withdrawing the top gas from a top portion of the stabilizer column; withdrawing the bottoms liquid from a bottom portion of the stabilizer column; and sending at least a portion of the bottoms liquid to a liquid storage tank.

Natural gas liquids (.NGL) removal and stabilization is standard industry practice in upstream oil and gas activities. The objective is to remove the heaviest hydrocarbons from natural gas, often coming from a wellhead, and which would condense in downstream natural gas treatment equipment. Heavy hydrocarbons are then separated into lighter (C4−) and heavier (C5+) compounds and sold as by-products (NGL).
In the liquefied natural gas (LNG) industry, NGL recovery systems are also present; particularly in large scale plants. The feed gas, generally pipeline quality natural gas, contains less heavy hydrocarbons than natural gas coming directly from a wellhead (usually hydrocarbon dew point specification is <10° C.); however, the heavy compounds still need to be removed to avoid any freezing at cryogenic temperatures. The standard solution is to add a scrubber column to remove most of the C4+ from the natural gas and send the bottom liquids to a stabilizer column that separates the light ends from the C5+ hydrocarbons. The bottom liquid can be stored under ambient conditions and sold as NGL.
For large scale plants, the top vapor can be recovered mixed with the process gas or sent back to the pipeline or further processed in additional columns such as a deethanizer etc. . . . .
However, for small-scale LNG plants (generally between <50 and 300 tons per day), the design is generally more CAPEX oriented, which means that the number of equipment is reduced as much as possible. However, depending on the heavy hydrocarbon content, and especially benzene, a scrubber and stabilizer columns may be necessary. In that case, the liquid bottom of the stabilizer can still be sold as NGL while the top vapor is generally used as fuel gas for the plant.
FIG. 1 provides an embodiment known heretofore. Natural gas 2, typically from a natural gas pipeline, is sent to a pretreatment stage 10 to remove items such as water and CO2 that might freeze downstream. This pretreated stream 12 is then sent to a cold box and scrubber 20, wherein the natural gas is separated out and liquefied to form liquefied natural gas (LNG) 22 and subsequently stored in LNG storage 30. Heavy hydrocarbons 24 are removed from the cold box and scrubber 20, expanded in valve V1, and then introduced into the NGL stabilizer column 40. Heavy hydrocarbon stream 24 contains primarily C4+ components and to a lesser extent, some methane, ethane and propane.
In the embodiment shown, a top gas 42, which contains primarily butane, is withdrawn from a top section of the stabilizer column 40, and then cooled in top condenser 45 before the resulting stream is sent to phase separator 50, wherein gas stream 52 is separated and likely used as fuel gas, with liquid stream 54 being sent back to the stabilizer column 40 as a reflux stream.
The bottoms liquid stream 44, which contains primarily natural gas liquids (NGL), is withdrawn from a bottom section of the stabilizer column 40, and then warmed in bottom reboiler before the resulting stream is sent to a second phase separator 60, wherein second gas stream 62 is separated and recycled back to the stabilizer column 40. The remaining liquid 64 is withdrawn from the second phase separator 60, and sent to NGL storage 70 after optional air cooling (not shown) and then flowing through valve V2.
Stabilizer units for LNG plants typically operate under warm conditions, which are between about 100 to 130° C. at the bottom of the column and about 20 to 50° C. at the top, and the columns are usually mounted with a bottom reboiler and a top condenser. The reboiler is used to ensure that the bottom liquid (NGL) is stable at its storage conditions (i.e. the Reid Vapor Pressure is lower than 1 bar). The top condenser reduces the saturation temperature of the top vapor by recovering some heavy compounds present at the top of the column. Having a top condenser generally also requires a separator drum and a pump to send the reflux back in the column. Unfortunately, this extra equipment for the top gas introduces excess equipment costs and complexity for a relatively low flow.
It is possible to operate the stabilizer without any reflux, which is shown in FIG. 2. As shown in FIG. 2, the top condenser 45, phase separator 50, and liquid pump have been removed. However, the vapor coming out from the top of the column is saturated at a higher temperature, between 60° C. and 90° C., and will condense as the pipeline carrying the vapor cools down. Therefore, this stream cannot be sent directly to the fuel gas system and this would require additional equipment to get rid of the liquid, thereby making it an inefficient solution.
Therefore, it would be beneficial to provide a process and apparatus for small-scale LNG plants that could provide the ability to stabilize the NGL from the bottoms liquid of the scrubber at a high efficiency while also being more economically feasible.

Operation of natural gas liquids stabilizer column

L'Air Liquide, Societe Anonyme Pour L'Etude Et L'Exploitation Des Procedes Georges Claude


A signature bundle inverting machine having a table for movement between a bundle receiving position and a rotating position for inverting bundles prior to transport to a binding machine. The table may also include a hoist-accessible position that permits the bundles to be removed from the table by a hoist or other lifting mechanism to reduce manual labor.

This invention relates generally to signature folders, stackers, and bundlers used in the printing industry that produce heavy bundles of signatures ready to be bound together to form books. More particularly, the present invention relates to a signature bundle inverter that inverts a heavy bundle of signatures from a stacking machine prior to delivery of the bundle to a binding machine so that the signatures are in a proper orientation for use in the binding machine.
In the publication industry books are manufactured using signatures which are a collection of four, eight, sixteen, or thirty two pages folded together and bound into books. With some existing stacking machines, signatures are formed and deposited on a receiving rack in a position that is inverted from a position that can be used in a binding machine. Consequently, a bundle of signatures must be inverted prior to being transported to a binding machine. Typically, the inversion process is done by "pocket feeders" in a bindery which must flip a bundle of signatures a lift at a time. Worker injuries, downtime, and high insurance costs all result from repetitive manual inversion of signature bundles. Numerous machines are used to handle bundles of signatures (see for example: Steinhart, U.S. Pat. No. 4,183,704; Kasamatsu et al., U.S. Pat. No. 4,725,180; Palamides, U.S. Pat. No. 5,353,576; and Kleinhen, U.S. Pat. No. 5,392,700). None of the prior signature handling machines receives vertical bundles of signatures directly from a stacking machine and inverts them to a position usable in a binding machine.
Thus, there is needed a signature bundle inverter that minimizes the use of manually lifting signature bundles and inverts the bundles quickly and efficiently for proper orientation prior to delivery to a binding machine.


The present disclosure relates to processing operations configured for intelligent management of a synchronization interval usable to synchronize data for an application/service between local data storage and distributed data storage. A classification prediction for a synchronization interval may be generated that is used as prediction for modifying the synchronization interval when a plurality of computing devices, linked to one or more user accounts, are used to access content. For instance, a suggestion is made as to whether a synchronization interval should be made faster, slower or even remain unchanged when a user account is accessing content. This may occur based on analysis of contextual factors described herein, thereby enabling a synchronization prediction component to make a best possible prediction for setting a synchronization interval. Artificial intelligence processing may be trained to generate the classification prediction for a synchronization interval. The classification prediction is utilized to manage modification of synchronization interval.

Currently, most applications/services sync user changes based on a fixed interval when the files are not actively collaborated on. However, a fixed synchronization interval is not the most efficient way to manage computing resources specifically when it can be identified that content is not frequently accessed. For instance, portions of content may not need to be synchronized each time an electronic document is accessed in cases where a content portion is not being edited or metadata otherwise modified. When unnecessary synchronization occurs, this creates an additional processing load on computing resources both client-side and server-side, increases latency in synchronization processing as well as represents inefficient management of a synchronization interval. When organizations manage a large amount of data, computing resources (e.g., server farms) can be greatly affected by the inefficient management.
In many technical instances, a synchronization interval is set to repeatedly backup content at a fast interval to minimize the chance that data is lost. When users are collaboratively accessing electronic content, a fast synchronization interval may be required due to the high likelihood that multiple users may access electronic content at any given time. However, that fast synchronization interval may not be required in instances where a single user account is accessing content. From a processing efficiency standpoint, it may not be beneficial to continuously adjust a synchronization interval at a fast rate when content is being accessed by a single user account because extra computing resources are tied up when they may not need to be, among other technical drawbacks.
Furthermore, another technical challenge is predicting when a user may next access electronic content is quite difficult. If a synchronization interval is not timely, there is a risk of data loss as well as creation of a poor user experience. Traditionally, there are no systems methods in place for management of a synchronization interval nor any systems or methods that attempt to correlate a prediction on user access with management of a synchronization interval.

Intelligent management of a synchronization interval for data of an application or service


The present invention is directed towards a back-reflection reduction device that is disposed between a support structure containing a plurality of optical waveguides and a bulk media. The support structure containing the optical waveguides has a substantially flat end face at which the optical waveguides terminate. Where the optical waveguides intersect the end face, they are substantially perpendicular to it. The back-reflection reduction device comprises a window disposed between the bulk media and the support structure. The window has a refractive index that is substantially identical to that of the optical waveguides. The window has an inner side that is affixed to the support structure and an opposing outer side. A gap exists between the window outer side and the bulk media. The gap provides an index of refraction substantially equal to unity.

Back reflection typically occurs in a fiber optic system when light in an optical system enters or exits a fiber and when light enters or exits a fiber optic component. Typical fiber optic components include fused fiber optic components and micro-optic components.
Examples of fused fiber optic components are fiber optic taps and fiber optic wavelength division multiplexers. In fused fiber optic components the light stays confined to the optical fibers but at least one optical fiber is distorted by one of several processes usually involving heating the fiber while twisting it around another fiber.
Micro-optic components include a variety of very small optical devices in which a microlens substantially collimates the light and free space processing of the light can occur. For instance, in a wavelength division multiplexer, the collimated light interacts with a thin film filter that has been coated to reflect one color of light while transmitting another. In another example, a 1 by 2 switch can be made by directing the collimated light from a microlens into one of two output ports. Complex optical crossconnect switches can be made in a manner similar to the 1 by 2 switch, except that the number of input and output optical fibers can reach 1000 or more.
In the case of micro-optic components, back reflection occurs at every successive interface between regions with different refractive indices and in particular when the light leaves the optical fiber in transit towards the microlens element. More specifically, when light travels from glass to air or air to glass, a reflection occurs at the glass/air interface.
The application of an anti-reflection coating usually can reduce the reflections from about 4% (a typical reflection at an uncoated glass-to-air interface) to about 0.25% over the range of wavelengths used in most optical systems. Typical industry standards for back reflection into an optical fiber call for reflections less than 0.00032% (−55 dB). The intensity of any reflections needs to be very small because reflections back into the optical fiber can destabilize the lasers that are used to generate the light.
In the fiber optics industry, two methods are commonly used to reduce back reflections. One approach involves angle polishing the fiber at approximately eight degrees so that light reflected from the end of the fiber does not get reflected back into the fiber. U.S. Patent Publication 2002/0097956A1 by Kikuchi et al. describes the application of this approach to the interface between optical fibers and the substrate of a microlens array. The second method involves the use of an index-matching fluid or gel at the interface. Since these fluids are index-matched to the fiber, very little light is back reflected when joining two fibers of the same refractive index with a small amount of index-matching fluid or gel. The back reflections in these cases are often of the order of 0.0001% (−60 dB).
In the case of a complex optical crossconnect switch, the optical fibers providing input to the microlens array are typically held in place in a fiber block. Polishing the fiber block at 8-degrees would leave some fibers closer to the microlens array than others. The variable distances to the microlens array inhibits uniformly collimating all the beams of light.
In U.S. Pat. No. 6,212,316 to Presley, a standoff block with a matched refractive index is placed between the optical fiber and the bulk material into which the light is directed. Presley shows the optical fiber to terminate substantially perpendicular to the interface with the standoff block. Although this approach would avoid the problem of having the optical fibers terminate at varying distances from a microlens array, the use of a solid standoff block affixed to both the optical fiber and the bulk media makes fine adjustments during or after assembly difficult, if not impossible.
What is required is a simple device for reducing back reflections that overcomes some of the difficulties encountered with prior art devices.


A cellular phone system, optimizing user demand by charging system subscribers according to a Variable Charge Rate (VCR) that is based on the price elasticity of the subscribers. According to the present invention, the service provider monitors the load in each cell and, for each cell, the service provider continuously determines a charge rate that can be tailored to specific subscriber category according to a number of variables, offering subscribers a VCR that is optimized for the individual cell's capacity and overall system capacity. According to an exemplary embodiment, subscribers may use mobile stations supporting the Short Message Service (SMS) to provide the subscribers with the broadcast VCR. The system can determine, in real time, optimal VCRs for individual cells to maximize revenue generated by the cell for any time of day. The VCRs may be selectively broadcast to the VCR-mobile station to inform subscribers of the current rate of charge for calls. VCRs may be tailored to specific categories of subscribers to provide better price differentiation between subscribers based on price elasticity of the subscribers categories.

The present invention relates to cellular telephone systems and, in particular, to a method and apparatus for controlling and optimizing the utilization of cellar telephone systems.
A cellular telephone system normally services an area populated by a number of users. Looking at FIG. 1, the service area of the system typically is divided up into cells (C1-C10), each equipped with a base station (BS1-BS10) capable of communicating with a number of users (M1-10) within the cell. Inherently, each cell has a maximum number of users that can be handled simultaneously. This is referred to as the cell's capacity. In addition, the service area containing the cells has an overall capacity. A critical factor which is taken into account in providing cellular telephone service to subscribers is the overall capacity of the system.
A basic problem with designing any cellular system is how much overall and individual cell capacity should be provided to ensure adequate service while maximizing revenues generated from the users of the cellular system. Complicating the design of such a system is the fact that the number of calls, or demand for use of the system, varies dramatically in each cell according to the time of day. On one hand, insufficient capacity during peak hours of system operation will cause congestion, and the inability to provide adequate service to users. On the other hand, providing too much unused capacity during off-hours under utilizes resources that increases overall cost of system operation. Therefore, it is important to optimize the trade-off between adequate capacity to handle anticipated subscriber demand for the system during peak usage while minimizing the unused capacity during off-hours. The more difficult of these two is how to maximize system usage during the hours when the system's capacity is largely idle.
Various methods and systems have been devised in order to maximize usage of the overall capacity of a cellular system at every time of day. In the past this has been attempted by varying the rate charged to subscribers of the system and its services at different times. For example, during peak hours, such as business hours when demand is at its greatest, all subscribers pay a full rate. However, as subscriber demand decreases, for example, during the evening and weekend hours, rates are reduced in one or more steps in order to encourage increased utilization of the system.
Varying the price is an effective means for regulating system demand because of the price sensitivity of subscribers. Certain subscribers are more price sensitive than others. This is known as a subscriber's price elasticity. For example, a personal use subscriber's price elasticity is much greater than a business use subscriber because, unlike a business use subscriber, a personal use subscriber's need to make a call is usually much less urgent or necessary. As a result, personal use subscribers may delay or make fewer calls for no other reason than the price of the call or because it comes out of their own pocket. Accordingly, personal use subscribers are more likely to be induced to use a system when rates are lower.
Cellular service providers often charge higher rates during the week, especially during working hours, for cellular calls. Because of these higher rates, certain subscribers who would otherwise use the cellular phone system are discouraged from making calls due to the higher rates. During peak hours, when the system is being used to near capacity, this is not a problem for the service provider because maximum revenue is being generated from system usage. However, when the system is not being used to near capacity, the service provider is not deriving any revenue from the unused system capacity and thus would like to be able to attract additional subscribers to make use of the system.
Further complicating the problem of maximizing use of available system capacity is that, even during peak hours of the overall system, certain cells may have surplus capacity and, therefore, are not generating their potential maximum revenue. For example, in FIG. 1 a cell in a city center (C1) may have its peak hour in the middle of the day, while a cell in a suburb (C9) may have its peak hour later in the afternoon. FIGS. 2A and 2B illustrate this problem in another way. FIG. 2A is an example of a macro-cell 21 with one micro-cell 22 indicated within. As illustrated in FIG. 2B while the load approaches maximum capacity for the macro-cell 21, a micro-cell 22 may only be at 60% capacity and thus have an unused surplus capacity even though the macro-cell 21 is congested. Typically, with state of the art cellular systems, service providers are forced to take all cells into account when choosing the time of day for rate reduction. Because the macro-cell 21 is at near capacity, the service provider cannot reduce the rate to increase revenues from the micro-cell 22. Additionally complicating matters is that by instantly lowering the rate the load on the entire system might sharply increase. In other words, these systems fail to take into account that different types of subscribers display different price elasticities and thus fail to maximize revenue for the system providers. These systems also do not address the problem that cheaper rates can only be offered when there is a substantial system wide excess capacity, because the load on the system might sharply increase with any broadcast of the lowering of the rate. Thus, if there is insufficient excess capacity, and a lower rate is offered, congestion will likely result.
Various systems have been contemplated in an attempt to address some of these problems. According to one approach described in U.S. Pat. No. 5,303,297 to Hillis, it has been suggested that system demand be monitored, and based on demand, a charge rate is dynamically calculated and broadcast to subscribers to encourage subscribers to use the system during non-peak times. However, Hillis does not describe how this charge rate is calculated. While the broadcast rate message solution does provide more flexibility than previous systems, it is not a complete solution to maximizing overall use of a system's excess capacity. The system of Hillis fails to consider a particular subscriber's price elasticity and thus the system indiscriminantly discourages some subscribers use of the system. This further results in inefficient use of the system's excess capacity and loss of potential revenue.
It has also been suggested that mobile phone calls could be charged according to where the calls are made, for instance, one price in an office, another on the street, and a third at home, etc. However, in this solution, as with the one described above, overload which might result from a decreased rate can only be alleviated by indiscriminately discouraging certain subscribers service and therefore cannot provide overall optimization of generating maximum revenues from the system.


At first, first transfer electrodes are formed selectively on a semiconductor substrate. Then, the surface of the first transfer electrodes are thermally oxidized at a temperature of 850.degree. to 950.degree. C. to form thermal oxide layers. After depositing a polycrystalline silicon layer over the substrate, rapid annealing is performed the first transfer electrodes, the thermal oxide layers and the polycrystalline silicon layer by a halogen lamp. Thus, after forming the polycrystalline silicon layer to be second transfer electrodes, annealing is performed by heating by lamp. Therefore, the thermal oxide layers can be efficiently heated by the irradiation heat from the polycrystalline silicon layer located upper side thereof and also from the first electrodes located at backside. Accordingly, the tolerance voltage of the thermal oxide layer can be improved and the thickness of the thermal oxide layer can be made thinner.

1. Field of the Invention
The present invention relates to a fabrication process of a solid-state image pick-up device with a CCD register which can improve a tolerance voltage of an insulation layer formed between transfer electrodes.
2. Description of the Prior Art
FIG. 1 is a plan view illustrating a construction of the conventional CCD type two-dimensional solid-state image pick-up device. A plurality of photodiodes 101 for photoelectric conversion are arranged in a form of a matrix array on a substrate. Vertical CCD registers 102 for transferring a charge in vertical direction are provided between respective row of the photodiodes 101. A horizontal CCD register 103 for transferring a charge in the horizontal direction is connected to the vertical CCD registers 102. A charge detector 104 for detecting a charge and an amplifier 105 for amplifying the output of the charge detector 104 are connected to one end of the horizontal CCD register 103.
In the solid-state image pick-up device constructed as set forth above, an image pattern is projected on the solid-state image pick-up device, at first. Then, charge depending upon intensity of the incident light on each of photodiodes 101 arranged in the matrix array is accumulated in each individual photodiode 101. Next, as time elapsed, the accumulated charge is shifted in the direction shown by arrow 110 and thus transferred to the vertical CCD register 102.
Next, the charge is transferred to the vertical CCD register 102 in the direction shown by arrow 111, to reach the horizontal CCD register 103. Subsequently, the charge is transferred in the horizontal CCD register 103 in a direction shown by arrow 112. Then, the charge is converted into a voltage in the charge detector 104 and thereafter output via the amplifier 105.
FIG. 2 is an illustration showing a part of section taken along line II--II of FIG. 1. A structure of unit pixel of the conventional CCD type two-dimensional solid-state image pick-up device will be discussed with reference to FIG. 2. A P-type well layer 21 is formed on the surface of an N-type semiconductor substrate 11. An N-type impurity region 13 to be a photodiode is selectively formed on the surface of the well layer 21. A high density P-type impurity region 25 is formed on the surface of the N-type impurity region 13. One side of the P-type impurity region 25 is positioned inside of the N-type impurity region 13 and the other side reaches the side surface of the N-type impurity region 13.
A P-type impurity region 26 to be a channel of MOS transistor is formed in the shallower region, adjacent one side of the N-type impurity region 13. An N-type impurity layer 15 to form the CCD register is formed adjacent the P-type impurity region 26. Also, a P-type impurity layer 23 is formed in a region facing with the lower surface of the N-type impurity layer 15. A high density P-type impurity layer 24 for isolation device is formed adjacent the other side of the N-type impurity region 13. The N-type impurity layer 15 and the P-type impurity layer 23 forming CCD register are formed via the P-type impurity layer 24.
Also, a gate insulation layer 31 is formed over the entire surface. A charge transfer electrode group 41 of polycrystalline silicon is formed selectively except for the region aligned with the P-type impurity region 25 on the surface of the gate insulation layer 31. On the entire surface of these, an interlayer insulation layer 33 is formed. A light shielding layer 51 preventing light from penetrating into a CCD channel (N-type impurity layer 15) is formed in a region aligning with the charge transfer electrode group 41 on the surface of the interlayer insulation layer 33.
In the unit pixel constructed as set forth above, a pn junction photodiode is formed with the N-type impurity region 13 and the P-type well layer 21. Accordingly, an incident light 61 of the N-type impurity region 13 from the upper side of the device is subject photoelectric conversion. Electron generated by this is accumulated in the N-type impurity region 13. At this time, the high density P-type impurity region 25 serves for reducing current generated at Si/SiO.sub.2 interface.
On the other hand, a MOS transistor is formed with the N-type impurity region 13, the CCD channel (N-type impurity layer 15) and the P-type impurity region 26. Accordingly, when a voltage pulse in a range of 10 to 15 V is applied to the charge transfer electrode group 41, the charge accumulated in the photodiode (N-type impurity region 13) can be transferred to the CCD channel (N-type impurity layer 15).
Subsequently, applying a voltage pulse in a range of -5 to -10 V to the charge transfer electrode group 41, the electron is transferred in the CCD channel (N-type impurity layer 15) in the direction shown by arrow 111 in FIG. 1. At this time, since the P-channel impurity region 26 serving as a channel of the MOS transistor becomes in cut-off condition, the charge accumulated in the photodiode (N-type impurity region 13) will never be discharged to the CCD channel.
FIG. 3 is a section taken along line III--III of FIG. 1. Structure of the CCD register of the conventional CCD type two-dimensional solid-state image pick-up device will be described with reference to FIG. 3. In FIG. 3, the N-type semiconductor substrate 11 and the P-type impurity layer 23 shown in FIG. 2 has been neglected.
As shown in FIG. 3, the N-type impurity layer 15 is formed on the surface of the P-type well layer (semiconductor substrate) 21. The gate insulation layer 31 is formed on the surface of the N-type impurity layer 15.
First transfer electrodes 4 made of a polycrystalline silicon are formed with a given interval on the surface of the gate insulation layer 31, and the surface thereof is covered with a thermal oxide layer 6. Second transfer electrodes 5 made of polycrystalline silicon are formed via the thermal oxide layer 6 between respective of the first transfer electrodes 4. The charge transfer electrode group 41 is formed with these first transfer electrodes 4 and the second transfer electrodes 5. Also, the first transfer electrodes 4 and the second transfer electrodes 5 are connected to four voltage supply lines 7a, 7b, 7c and 7d, respectively in the sequential order of arrangement of the lines.
In the CCD register constructed as set forth above, the foregoing voltage pulse in the range of -5 to -10 V is applied to the first transfer electrodes 4 and the second transfer electrodes 5 forming the charge transfer electrode group 41. FIG. 4 is an illustration showing a voltage pulse waveform to be applied to the transfer electrodes from the voltage supply lines 7a to 7d. Four phase pulse voltages of .phi.a to .phi.d are applied from the four voltage supply lines 7a to 7d. As the pulse voltage, a pulse voltage having a reference voltage of 0 V and amplitude of -5 to -10 V may be employed, for example. Then, the electron is transferred in the N-type impurity layer 15 as the CCD channel in the direction shown by allow 111.
FIGS. 5A to 5D are sections showing fabrication process of the CCD register in order of sequence. As shown in FIG. 5A, the N-type impurity layer 15 is formed on the surface of the P-type well layer 21, employing known technology. Then, the gate insulation layer 31 is formed on the N-type impurity layer 15.
Next, as shown in FIG. 5B, a polycrystalline silicon layer (not shown) is deposited on the surface of the gate insulation layer 31 by way of CVD method or the like. By selectively removing the polycrystalline silicon layer, the first transfer electrodes 4 are formed. It should be noted that, upon deposition of the polycrystalline silicon, if impurity such as phosphorous or the like, is not doped in the polycrystalline silicon layer, a process step to diffuse impurity, such as phosphorous by way of thermal diffusion method after deposition of the polycrystalline silicon layer. Next, the thermal oxide layer 6 is formed by thermal oxidation of the surface of the first transfer electrode 4.
Subsequently, over these surfaces, a polycrystalline silicon layer 5a is deposited.
Then, as shown in FIG. 5D, a portion of the polycrystalline silicon layer 5a above the first transfer electrodes 4 is selectively removed. By this, the second transfer electrodes 5 are formed. The conventional CCD register is thus fabricated.
A In the conventional CCD register, the charge transfer electrode group 41 has a function to read out the charge from the photodiodes (N-type impurity region 13) to the vertical CCD channel (N-type impurity layer 15) and a function to transfer the charge in the CCD channel. Accordingly, the pulse voltage in a range up to 15 V is applied to the thermal oxide layer 6 isolating between the first transfer electrodes 4 and the second transfer electrodes 5.
However, the thermal oxide layer 6 formed by thermal oxidation of the surface of the first transfer electrode 4 made of the polycrystalline silicon, has low tolerance voltage, and, in general, can obtain electric field strength of merely about 1 to 2 (MV/cm). Accordingly, in order to obtain the tolerance voltage of 15 V, the thermal oxide layer 6 should be formed in the thickness greater than or equal to 0.2 .mu.m. Particularly, in case of the solid-state image pick-up device having large area, lack of tolerance voltage of the thermal oxide layer 6 inherently lower yield significantly.
When the thickness of the thermal oxide layer 6 is increased seeking for improvement of the tolerance voltage, a step to be formed between the portion where the first and second transfer electrodes 4 and 5 overlap to each other and the portion where the transfer electrodes are not formed (photodiode portion) becomes greater than or equal to 1 .mu.m. By this, coverage of the metal electrode layer (light shielding layer 51) to be formed on the surface of the charge transfer electrode group 41 is lowered at the step portion and the metal electrode layer becomes thin in the vicinity of the step portion. If the thin layer portion is formed in the metal electrode layer, and the light penetrates into the CCD register, the penetrated light is converted into the charge by photoelectric conversion in the CCD. Then, such charge is added to the signal charge to be a pseudo signal to cause lowering of S/N ratio.
When the metal electrode layer (light shielding layer 51) is used as wiring, breakage of the wiring can be caused at the step portion. By this, voltage cannot be applied to the transfer electrode.
In this fact, in the insulation layer between the polycrystalline silicon layers to be the transfer electrode, it has been strongly demanded to form insulation layer which is thin in the thickness and can improve tolerance voltage.
In general, as one of causes of low tolerance voltage of the thermal oxide layer (insulation layer) formed on the polycrystalline silicon layer, the surface of the polycrystalline silicon layer at the interface between the polycrystalline silicon layer and the thermal oxide layer after thermal oxidation is unevenness. Thus, for planarizing the surface of the polycrystalline silicon layer to improve the tolerance voltage of the thermal oxide layer, there has been proposed a method to perform oxidation of the surface of the polycrystalline silicon layer to be the transfer electrode at high temperature higher than or equal to 1000.degree. C. (R. M. Anderson et al., "Evidence for surface asperity mechanism of conductivity in oxide grown on polycrystalline silicon", Journal of Applied Physics, Vol. 48, No. 11, 1977, pp 4834-4836). This will be hereinafter referred to as "first prior art".
When the thermal oxide layer is formed by the first prior art, mechanical strain caused at the interface of the polycrystalline silicon layer and the thermal oxide layer can be reduced by oxidation process at high temperature to reduce unevenness at the interface.
Also, there has been proposed a method to planarizing the surface of the polycrystalline silicon layer. (K, Shinada et al., "Reduction in Polysilicon Oxide Leakage Current by Annealing prior to Oxidation", Journal of Electrochemical Society, SOLID-STATE SCIENCE AND TECHNOLOGY, Vol. 132, No. 9, 1985, pp 2185-2188). The proposed technology is to enlarge crystal grain size of the polycrystalline silicon layer by appropriately defining phosphorous concentration in the polycrystalline silicon or by performing annealing process to the polycrystalline silicon layer before oxidation of the surface of the polycrystalline silicon layer, for planarizing the surface of the polycrystalline silicon. This will be hereinafter referred to as "second prior art".
Also, there has been proposed a method for reducing unevenness of interface between the polycrystalline silicon and the thermal oxide layer for improving tolerance voltage by providing annealing process for the thermal oxide layer at high temperature after oxidation of the polycrystalline silicon layer. (D. K. Brown et al., "Ramp Breakdown Study of Double Polysilicon RAM's as a Function of Fabrication Parameters", Journal of Electrochemical Society, SOLID-STATE SCIENCE AND TECHNOLOGY, Vol. 130, No. 7, 1983, pp 1597-1603). This will be hereinafter referred to as "third prior art". However, even by the first to third prior arts set forth above, it has not been possible to sufficiently improve the tolerance voltage of the insulation layer. Furthermore, since the foregoing prior arts require heat treatment at high temperature higher than or equal to 1000 .degree. C, if such prior art is applied to the solid-state image pickup device, diffusion depth of the PN junction can be restricted. Accordingly, these technology is difficult to apply for the solid-state image pick-up device.

Fabrication process for solid-state image pick-up device with CCD register