A switching assembly includes an operating assembly and a fixed contact assembly including a first fixed contact, a second fixed contact, a third fixed contact, a fourth fixed contact, and a number of terminals. The number of terminals includes a first terminal, a second terminal, and a third terminal. The switching assembly also includes a movable contact assembly that includes a first movable contact and a second movable contact. The first movable contact is movable between a first position and a second position. The second movable contact is movable between a first position and a second position. The operating assembly is coupled to the movable contact assembly and moves the first and second movable contact assemblies between the first and second positions. The switching assembly also includes a shunt assembly including a number of shunts. The shunt assembly is configured in one of a series configuration or a parallel configuration.

Field of the Invention
The disclosed and claimed concept relates to a switching assembly for aircraft and, more specifically, to a switching assembly structured to be used in a series configuration or a parallel configuration.
Background Information
The "More Electric Aircraft" is rapidly evolving. New aircraft designs are increasingly forsaking heavy, maintenance-intensive and vulnerable hydraulic and pneumatic subsystems in favor of electro hydrostatic actuators (EHAs). EHAs, which combine electric and hydraulic power, are control systems designed to enhance aircraft performance while reducing weight by eliminating tubing, pumps and valves required for aircraft with traditional controls. The existing 115 VAC and 28 VDC aircraft power supplies are not sufficient to meet the increased electric power demand. Accordingly, the aircraft industry is seeking to utilize a high voltage supply to meet power requirements. One system that appears to be suitable utilizes a 270/540 VDC power supply.
There is, therefore, a need for a switching assembly structured to be used with either a 270 VDC or a 540 VDC power supply. There is a further need for the switching assembly to utilize substantially the same components so that the switching assembly is configurable to the needed current.

Multiple configuration switching assembly


Disclosed is an image forming apparatus, which makes it possible to reduce the frequency of image defect occurrences to a level as lower as possible by detecting abnormalities generated with age on the photoreceptor member and/or in the cleaning section, so as to suppress an amount of spoiled paper sheets and material. The image forming apparatus includes: a light source that is disposed at a position located between a cleaning section and a charging section, to emit an inspection light, which is to be irradiated onto a photoreceptor member over a main-scanning direction thereof; a tight-contact type image sensor that has a line image sensor to receive the inspection light reflected from a surface of the photoreceptor member; and a control section to determine a status of a surface of the photoreceptor member, based on a result of analyzing the inspection light receive by the line image sensor.

The present invention relates to an image forming apparatus that forms an image based on image data, and transfers the image onto a paper sheet, so as to conduct a printing operation.
An image forming apparatus forms an image based on image data onto a photoreceptor drum, and transfers the image onto a paper sheet directly or through an intermediate transfer belt. Concretely speaking, when forming the image, the image forming apparatus forms a latent image onto the photoreceptor drum through the exposing process including steps of uniformly charging the photoreceptor drum, and irradiating light, which is emitted from a laser diode or the like, and the intensity of which is modulated on the basis of the image data, onto the photoreceptor drum. Successively, the latent image formed on the photoreceptor drum is developed with toner, fed from a developing section, so as to form a toner image thereon. Still successively, the concerned toner image is directly transferred onto the paper sheet at a transferring section, or the concerned toner image is primarily transferred onto the intermediate transfer belt, and then, the toner image transferred onto the intermediate transfer belt is further transferred onto the paper sheet at a secondary transferring section. After the transferring operation has been completed, a cleaning section removes residual toner remaining on the photoreceptor drum from the circumferential surface thereof, and further, a discharging section discharges the residual electric potential still residing on the circumferential surface of the photoreceptor drum, so as to prepare for the next image forming operation.
In the image forming apparatus as abovementioned, since the printing operation is achieved by transferring the toner image, formed on the photoreceptor drum, onto the paper sheet as its final step, if a certain abnormality, such as a scar or the like, resides on the photoreceptor drum, an abnormal image would be transferred onto the paper sheet, and accordingly, sometimes, it would become difficult to obtain a good printing result.
To cope with such the drawback, for instance, Tokkaihei 7-55710 (Japanese Patent Application Laid-Open Publication) sets forth a defect inspection apparatus that detects a surface defect, such as a scar or the like, generated on the circumferential surface of the photoreceptor drum currently manufactured. The defect inspection apparatus concerned includes: a light source to irradiate a light onto the photoreceptor drum in a direction of the circumferential surface axis thereof, a line sensor that receives a reflected light reflected from the irradiation surface so as to detect the intensity of the reflected light; and a signal processing section to process the signal outputted from the line sensor; so as to make it possible to detect the defect by focusing a bright image section and a dark image section, formed on the circumferential surface of the photoreceptor drum, onto the line sensor.
Further, in order to detect a deterioration of the charging device, Tokkaihei 7-191580 (Japanese Patent Application Laid-Open Publication) sets forth an electro-photographic type recording apparatus that is provided with: a line sensor that is disposed downstream the developing device so as to read a visual image residing on the circumferential surface of the photoreceptor drum located upstream the charging device; a detecting section that processes a signal read by the line sensor so as to detect an abnormal visual image; and an abnormal visual-image detection control section.
Still further, recently, since the toner, which is to be employed by the image forming apparatus, tends to be increasingly finer than ever in conjunction with the trend of achieving a high quality of the reproduced image, it becomes difficult to maintain the cleaning efficiency over a long term. On the other hand, in order to suppress a cost for a unit printing, it has been desired that the time for exchanging the cleaning section be made to delay later, so as to use the concerned cleaning section as longer as possible. In addition, in the conventional practice, the exchange time has been set at a predetermined timing (in conformity with the PM (Parts Management) cycle), or at such a time when a certain defects has appeared before the predetermined timing arrives, though the duration time (durable term) of the cleaning section depends on environmental factors. Accordingly, there has been desired such a system that makes it possible not only to maintain the cleaning efficiency as longer as possible, but also to suppress the wasted exchange of the cleaning section. Further, in such a image forming apparatus that is provided with the cleaning mechanisms in regard to both the intermediate transfer member and the secondary transferring member, there has arisen another problem that it takes much time for specifying a portion where the cleaning deficiency currently occurs.
Conventionally, Tokkai 2009-199036 (Japanese Patent Application Laid-Open Publication) sets forth a residual toner inspection apparatus that inspects the cleaning efficiency of the photoreceptor member abovementioned. The residual toner inspection apparatus concerned is provided with: a laser beam irradiating section to irradiate a laser beam in parallel onto an area in the vicinity of the viewing surface of the photoreceptor member concerned; and an observing section to observe scattering light generated by the abovementioned laser beam on the circumferential surface of the photoreceptor member.
However, since the defect inspection apparatus set forth in Tokkaihei 7-55710 conducts the inspection of the manufactured photoreceptor member before the photoreceptor member concerned is installed into the image forming apparatus, it is impossible to detect the scars or the like, which have been generated over time on the circumferential surface of the photoreceptor member.
Further, since the apparatus set forth in Tokkaihei 7-191580 detects a deterioration of the charging device by viewing a visual image, it is impossible to evaluate the cleaning efficiency.
Still further, since the residual toner inspection apparatus set forth in Tokkai 2009-199036 conducts the operation for evaluating the cleaning member of the image forming apparatus before the cleaning member concerned is installed into the image forming apparatus, it is impossible to evaluate the efficiency deteriorations of the cleaning member, which have been caused by the image forming cycles repeatedly conducted over time in the image forming apparatus concerned. In this connection, although the Tokkai 2009-199036 also sets forth that the residual toner inspection apparatus may be installed into an actual image forming apparatus, it would be practically difficult (or virtually impossible) to install the concerned apparatus into the actual image forming apparatus from a special factor and a cost effective points of view, since the observing operation is achieved by shifting the CCD (Charge Coupled Device) imager to be included in the observation section in an axis direction of the photoreceptor member (photoreceptor drum).

Image forming apparatus with a photoreceptor

Konica Minolta Business Technologies, Inc.


A delivery control device, which is installed in repeater equipment interposed between a content delivery server device and a client device so as to repeat delivered contents, controls delivery speed for contents by adopting pacing delivery depending on delayed conditions of networks and the operating condition of the client device according to the ABR (Adaptive Bit Rate) delivery method. The delivery control device includes a delivery speed calculation part configured to calculate real delivery speed for sequentially delivering the divided files, which are produced by dividing file data representing contents to be delivered to a client device, in an order of reproducing contents, and a delivery speed determination part configured to determine delivery speed for the divided files based on the real delivery speed calculated by the delivery speed calculation part, the presumed delivery speed determined in advance, and predetermined thresholds relating to intervals of receiving the divided files.

Conventionally, technologies have been developed with respect to bandwidth control in content delivery. For example, Patent Literature 1 discloses a bandwidth control method in content delivery. Patent Literatures 2 and 3 disclose cache servers for preventing a reduction of user QoE due to variations of bands in content delivery through mobile networks. Patent Literature 4 discloses a server device that transmits to a client device media data encrypting contents at a single media rate selected from among multiple media rates. Patent Literature 5 discloses a transmission band delivery method for delivering transmission bands depending on the priority for each connection when distributing bands (e.g. ABR (Available Bit Rate) bands) between multiple connections. Patent Literature 6 discloses an ABR (Available Bit Rate) service quality estimation device.
Recently, according to the advancement of Internet technologies, electronic devices having communication functions have been connected to networks, in particularly, communication traffic has increased due to the spreading of mobile terminal devices and smartphones; this nay increase the burden of loads to network facilities of common carriers. For this reason, various studies have been made to improve client QoE (Quality of Experience) without causing higher traffic than necessary. For example, it is necessary to control traffic for content delivery according to the recently-developed ABR (Adaptive Bit Rate) delivery method.
The ABR delivery method is used for delivering contents such as moving pictures and sounds. Non-Patent Literature 1 teaches HTTP Live Streaming (HLS) as one example of the ABR delivery method. According to the content delivery of HLS, a single content is divided into multiple segments, and therefore their segment files are delivered to a client device. The RLS provides a playlist file (or an index file) describing URLs (Uniform Resource Locators) of segment files for a single content in an order of playback times and multiple types of segment files having different bit rates for a single content, and therefore it uses a variant playlist (Variant Playlist) describing the URL of a playlist corresponding to each bit rate. First, a client device acquires a variant playlist so as to select a playlist file, corresponding to the bit rate suited to viewing environments, from among playlist files described therein. Then, the client device sequentially retrieves segment files described in the selected playlist file so as to reproduce contents.
To delivery contents such as video and audio contents, a pacing (Pacing) delivery technology has been developed as a method for suppressing network traffic without sacrificing reproduction quality at client devices. For example, Patent Literature 1 teaches a pacing delivery control device adapted to a gateway device located between a client device and a content delivery server device according to the ABR delivery method. The pacing delivery control device retrieves bitrate information used for delivering contents from a playlist file corresponding to the contents to be delivered to a client device, thus controlling bandwidths allocated to the client device depending on a target bitrate set to the client device. This makes it possible for the client device to guarantee the target bitrate. In addition, it is possible to prevent the occurrence of burst traffic due to usage of the entire bandwidth for the client device in networks including a content delivery server device, a gateway device, and a client device.

Delivery control device and delivery control method for content delivery according to ABR delivery method


Method and apparatus for testing a parallel optical transceiver are provided. One embodiment provides a built-in self-testing (BIST) parallel optical transceiver comprising a full-rate clock test pattern generator and a clock divider circuit connected to provide a half-rate clock signal to one of the one or more transmitter channels, and an error detector comprising one or more error detection circuits connected to one or more receiver channels and configured to receive the half-rate clock signal. Another embodiment provides a method for testing a parallel optical transceiver, comprising: generating a full-rate clock test pattern to one or more transmitter channels; providing a half-rate clock signal to one of the one or more transmitter channels utilizing a clock divider circuit; transmitting test pattern and half-rate clock signals to one or more corresponding receiver channels; and detecting error utilizing one or more error detection circuits connected to receive the half-rate clock signal.

1. Field of the Invention
The present invention generally relates to testing of optical transceivers. More particularly, the invention relates to built-in self-test of parallel optical transceivers.
2. Background of the Related Art
The growth of electronic commerce, particularly via the internet, has produced exponential increases in the demand for communication bandwidth for computer networks as well as data storage and retrieval networks. In response to the communication bandwidth needs, optical fiber-based data communication devices are being developed. Most previously known optical link development has focused on serial transceivers (or transmitters and receivers). Recently, the focus has shifted to development of parallel transceivers because of the potential for high aggregate bandwidth and lower costs. Furthermore, parallel transceivers may be designed to handle data which has not been coded or serialized for transmission, which may replace wired buses and connect computers at higher data rates and over longer distances.
However, reliable manufacture and low-cost testing of parallel transceivers pose a number of problems, and manufacturing yields can be reduced significantly due to increased complexity in both chip and module construction. Since testing equipment for parallel transceivers are generally unavailable, utilizing conventional testing equipment and method designed for testing serial transceivers multiplies the testing time when applied to parallel transceivers. Furthermore, existing test equipment are not designed to handle the electrical interface of DC-coupled transceivers. Also, present limitations of the opto-electronic components also require that full-rate testing of a parallel optical transceiver does not rely on transmission of a full-rate clock signal.
Therefore, there is a need for a built-in self-test (BIST) circuit disposed on a parallel optical transceiver which may be utilized in development and manufacturing test and field debug of the parallel optical transceiver. It is desirable for the BIST to serve as a preliminary screen of proper link functions of the parallel optical transceiver. For debugging purposes, it is further desirable for the BIST to identify the faulty channel(s) of the parallel optical transceiver. It is also desirable for the BIST to exercise optical links with full-rate data patterns that closely resemble those transmitted in typical functional or operational mode.
One embodiment provides a built-in self-testing (BIST) parallel optical transceiver comprising a full-rate clock test pattern generator connected to one or more transmitter channels, a clock divider circuit connected to provide a half-rate clock signal to one of the one or more transmitter channels, and an error detector comprising one or more error detection circuits connected to one or more receiver channels, the one or more error detection circuits configured to receive the half-rate clock signal. Each error detection circuit may comprise a first scan chain comprising a plurality of rising-edge-triggered flip-flops configured to receive the half-rate clock signal, a second scan chain comprising a plurality of falling-edge-triggered flip-flops configured to receive the half-rate clock signal, and an error output connected to the first and second scan chains.
Another embodiment provides an apparatus for testing a parallel optical transceiver, comprising: a full-rate clock test pattern generator connected to one or more transmitter channels of the parallel optical transceiver; a clock divider circuit connected to provide a half-rate clock signal to one of the one or more transmitter channels; an error detector comprising one or more error detection circuits connected to one or more receiver channels of the parallel optical transceiver, the one or more error detection circuits configured to receive the half-rate clock signal; and a test fixture comprising optical connections connecting outputs of the one or more transmitter channels to inputs of the one or more receiver channels.
Another embodiment provides a method for testing a parallel optical transceiver, comprising: generating a full-rate clock test pattern to one or more transmitter channels; providing a half-rate clock signal to one of the one or more transmitter channels utilizing a clock divider circuit; transmitting full-rate clock test pattern and half-rate clock signal through the one or more transmitter channels to one or more corresponding receiver channels; and detecting error utilizing an error detector comprising one or more error detection circuits connected to the one or more receiver channels, the one or more error detection circuits configured to receive the half-rate clock signal.

Architecture for built-in self-test of parallel optical transceivers

International Business Machines Corporation


In a high-reverse-voltage GTO thyristor, a negative beveling (6) with comparatively high beveling angle (.alpha.) is possible as edge contouring as a result of separating the p-type base layer into a central p-type base layer (4) of small depth and high edge concentration and a p-type base edge layer (5) of greater depth and lower edge concentration.. The production of the two p-type base layers (4, 5) is preferably carried out by simultaneous diffusion of two acceptors with different diffusion constants.

1. Field of the Invention
The present invention relates to the field of the power semiconductor. It relates in particular to a gate turn-off thyristor for high reverse voltages, comprising
a p-type emitter layer, an n-type base layer, a p-type base layer and a cathode-side gate-cathode structure in a semiconductor substrate between an anode and a cathode; and PA0 a beveling at the substrate edge to reduce the upper surface field strength. PA0 the p-type base layer is subdivided into a central p-type base layer and a p-type base edge layer which surrounds the p-type base layer, PA0 the active part of the thyristor is disposed in the region of the central p-type base layer, PA0 the p-type base edge layer has a greater thickness than the central p-type base layer, PA0 the p-type base edge layer has a lower doping concentration than the central p-type base layer, PA0 the beveling is constructed as negative beveling, PA0 the negative beveling is disposed in the region of the p-type base edge layer, and PA0 cuts the pn junction formed by the p-type base edge layer and the n-type base layer. PA0 a first predeposition layer containing an accepter material with a high diffusion constant is introduced into the n-type doped semiconductor substrate on the cathode side in the edge region; PA0 a second predeposition layer containing an accepter material with a low diffusion constant is introduced into the n-type doped semiconductor substrate on the cathode side at least in the central region; PA0 in a subsequent diffusion step, the acceptors are simultaneously diffused into the semiconductor substrate from the two predeposition layers; and PA0 after the remaining structure of the thyristor has been produced, the negative beveling is provided at the substrate edge.
The invention relates furthermore to a process for producing such a gate turn-off thyristor.
2. Discussion of background
For a planar pn junction in a semiconductor component, for example a high-power thyristor, to be able to block high voltages (>1000 V), special measures have to be taken in the edge region of the disk-shaped component substrate in order to reduce the increased field strength occurring at this point.
Known measures essentially comprise a lateral structuring of the doping zones, and specifically, either as external contouring by grinding off or etching out (positive, negative beveling; trench etching; mesa etching or substrate etching; in this connection see V.P. Sundersingh and A. A. Ghatol, Int. J. Electronics, Vol. 54, No.1 (1983), pages 127-137), or by introducing special doping structures (for example, in the form of so-called "guard" rings).
In the case of low-power gate turn-off thyristors, a simple trench edging which interrupts the otherwise planar pn junction between p-type base layer and n-type base layer has proved successful as edge contouring (on this point see: Brown Boveri Technik, 9 (1986), pages 519-525).
In the quite differently constructed field-controlled thyristors, the provision of a double trench which represents a combination of mesa and trench edging is furthermore known as edge contour (EP-A2-0,178,387). In order to provide sufficient space for the double trench, the very thin (5 .mu.m) and only slightly p-type doped (10.sup.16 cm.sup.-3) gate region merges at the edge into a deeper-drawn edge region which may be introduced into the semiconductor substrate, for example, by the selective aluminum diffusion known from EP-A2-0,216,954.
Hitherto no detailed solutions have been specified for the edge contouring of high-reverse-voltage GTO thyristors. Thus, the publication IEEE Trans. Electron Devices, vol. ED-28, No. 3 (1981), pages 270-274 has described only a GTO thyristor having a reverse voltage of 2500 V whose edges have been beveled by sandblasting. However, the said publication does not specify either the lateral doping profile of the p-type base layer nor does it deal with the type (positive or negative), shape and position of the said beveling.
A particularly simple, inexpensive solution which is compatible with pressure contacting is the wedge-shaped partial grinding of the slice edge at a small negative angle (the abovementioned negative beveling). However, an adequate reduction in the electric field strength at the edge is only possible with this technology if the beveling angle is either extremely small (=approx. 1.degree.) or the blocking pn junction is not too strongly asymmetrical (thickness of the pn junction >70 .mu.m; doping concentration at the edge of the p-type profile <5.times.10.sup.17 cm.sup.-3).
Applying negative beveling to high-reverse-voltage GTO thyristors with planar pn junction would therefore raise the following problem: the p-type base layer of these components has both to be highly doped (edge doping concentration N.sub.po >10.sup.18 cm.sup.-3) and also have a small thickness or depth (penetration depth of the p-type base layer X.sub.Jp <70 .mu.m).
An adequate reduction of the edge field strength would then only be achievable with the so-called small beveling angles. Such small beveling angles require, however, a wide edge region and consequently a loss of active area. In addition, they can be produced with the necessary precision only with difficulty.


A data coding system that compresses data and enables data, e.g., prefix addresses, to be represented with significantly fewer memory cells when compared to conventional coding systems.

1. Field of the Invention
The present invention relates generally to data coding systems.
2. Description of Background Art
A Content Addressable Memory (CAM) has a number of storage locations in which data can be stored. Once data is stored in a location, the location can be addressed using the content (data value) of the location. An input word is compared against a table of allowed values. If there is a match, the location of the matched word is returned. The location is typically used to address a related table and a corresponding word is returned. One application of CAMs is in internet protocol (IP) packet classification where IP addresses and other fields of an internet packet are compared in network switches and routers. In a common form of IP addresses, called a subnet address or an address prefix, definite values are specified for a certain number of bits and the rest of the bits of the address are specified as "x" (don't care) bits. An example for IPv4 addresses is given below:
0110 1100 0111 xxxx xxxx xxxx xxxx xxxx
The bits that are not x (don't care) form the prefix of the address, and the number of prefix bits is called prefix length. A subset of the classification application is to identify the matching prefix that has the longest number of prefix bits. In the more general classification application, several fields must match simultaneously. An example specification for classification is shown in the table of FIG. 19.
Additional fields may be used in the classification, for example 144 bits of specification can be used for Internet Protocol version four (IPv4) classification. In Internet Protocol version six (IPV6), the length of each address field is 128 bits long, and a classification specification can exceed 576 bits. A key characteristic of classification specifications is that each of the fields can have x (don't care) bits. Thus CAMs for classification must permit x (don't care) bits that are not necessarily contiguous. A class of CAMs called ternary CAMs has been introduced to address this need, where there is an extra bit associated with every data bit, called the mask bit.
There are many disadvantages with the conventional ternary CAM structure, however. Since each cell contains two memory cells, and a mask-and-compare circuit, implementation of a table of size w×2n requires w×2n+1 memory elements, and w×2n mask-and-compare circuits. Since every lookup in the table requires the activation of all the cells, power consumption is proportional to w×2n. For large values of n, the cost is considerable, and the power consumption is prohibitive. In addition, since the comparison logic is repeated in every cell, it is expensive and difficult to provide different kinds of comparison, and the typical CAM provides only bit-for-bit compares.
What is needed is a data coding system that compresses data and enables data, e.g., prefix addresses, to be represented with significantly fewer memory cells when compared to conventional coding systems.


A frequency doubler operating where the predetermined duty cycle is essentially 50% in response to a series of input pulses with a given frequency and a duty cycle essentially of 50%. The circuit includes a means to generate a ramp signal which the ramp portion forms as a function of the repetition of the input pulses in response to the input pulses, an exclusive-OR logic to evaluate the exclusive-OR of the output from the ramp signal generating means and the input pulses in response to the output from the ramp signal generating means and said input pulses. A means, which is coupled to the ouptut of said exclusive-OR logic, integrates the output of the exclusive-OR logic, adds it to the ouptut from the ramp signal generating means, and feeds it back to the input of the exclusive-OR logic. A means, which is coupled to the integrating and feedback means, and causes the duty cycle of the output from the exclusive-OR logic to become essentially 50% by applying reference voltage.

The semiconductor chip of microcomputers, microprocessors, etc. are operated by the function of a series of clock pulses. For example, the microcomputer semiconductor chip called "80286" which can presently be obtained in the marketplace requires a series of clock pulses with frequency of 30 MHz. However, it is difficult to procure quartz oscillators suitable for generating 30 MHz, and moreover, they are expensive. Therefore, it is desirable to be able to obtain clock signal generators in which the frequency of about 30 MHz is generated by multiplying the frequency of a low frequency quartz oscillator which is low in cost and is presently obtainable in the marketplace.
A typical frequency multiplier of clock pulses uses the conventional phase lock loop technology. However, using a phase lock loop requires a voltage control oscillator, a phase comparator, a frequency divider and other circuits. This complicates the shape of the circuit and increases the cost of the multiplier.
A different type of frequency multiplier uses an exclusive-OR logic circuit which has been adapted so that input pulses are received at one input terminal while the integrated output of the input pulses integrated with a predetermined time constant when the duty cycle of said input pulse is essentially 50% is received at the other input terminal. Suppose the duty cycle of the input pulse is 50% and the time constant of the integration is suitably selected, an output in which the frequency is doubled can be obtained with an duty cycle of essentially 50%. However, when the frequency of the input pulse fluctuates, the duty cycle of the output with doubled-frequency varies in accordance to it. This makes it impossible to use the frequency multiplier as the clock pulse source of the semiconductor chip.

Circuit for multiplying the frequency in one series of input pulses


A dental blank has at least an inner zone (or layer) of a first color and an outer zone (or layer) of a second color, wherein the inner and outer zones are concentric. The inner zone can be surrounded in its entirety by the outer zone such that only the outer zone is visible on all surfaces of the blank. Alternatively, the inner zone and the outer zone can extend to a same single surface of the blank, such that only the outer zone covers all remaining surfaces. The blank may also have an intermediate zone between the inner and outer zones. A method of fabrication includes solid free form processes, such as robocasting, laser sintering and 3D printing that allow for placement of multiple colors. A dental restoration made from the blank can have a variety of shades depending on a ratio of milled outer layers to internal layers.

Presently, dental blanks are composed of a single color, or of multiple colors layered on top of each other. The monochromatic blocks may not match the natural color gradation found in natural teeth. Furthermore, shades of these colored blocks are limited in number, and may not even match an overall base shade of a tooth.
One known type of block does have three layers of color. However, these layers extend fully to surfaces of the block, and result in restorations with sharp gradations in color, as opposed to natural teeth which have gradual changes in color. Furthermore, natural teeth have color generated internally by overlapping colors from the enamel and dentin of the tooth.
Conventional methods of fabricating dental blocks involve pressing powders into a mold or using an extrusion from which blocks are then fired to full density. These are time and labor intensive processes and do not easily allow for placement of multiple colors as desirable for dental blocks with improved color matching.
Accordingly, it would be desirable to provide a blank with color zones which correspond to colors found in natural teeth. Moreover, it would be desirable to provide a blank from which restorations with varying ratios of color thicknesses can be produced. It would also be desirable to provide a method of fabrication of dental blocks that readily allows for placement and incorporation of multiple colors.


A spin valve thin-film magnetic element has an improved rate of change in resistance (xcex94R/R) that can be used for a narrower magnetic track. The spin valve thin-film magnetic element has a laminate that include an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic conductive layer, a free magnetic layer, a back layer, specular-reflection layers and a pair of electrode layers formed at the two sides of the laminate. Preferably the specular reflection layer includes an oxide, such as xcex1-Fe2O3 or NiO, or a half-metal Heusler alloy, such as NiMnSb or PtMnSb.

The present invention relates to spin valve thin-film magnetic elements having an electrical resistance that is defined by the relationship between the fixed magnetization direction of a pinned magnetic layer and the magnetization direction of a free magnetic layer that is influenced by an external magnetic field. The present invention also relates to thin-film magnetic heads having spin valve thin-film magnetic elements. In particular, the present invention relates to a technique in which the soft magnetic characteristics of the free magnetic layer and the rate of change in resistance of a spin valve thin magnetic element is improved.
A spin valve thin-film magnetic element is a giant magnetoresistive (GMR) element having giant magnetoresistance effects. A spin valve thin film can detect magnetic fields recorded in a recording medium, such as a hard disk.
The spin valve thin-film magnetic element has a relatively simple structure among the GMR elements. Since the rate of change in resistance of a spin valve thin-film magnetic element is high in response to an external magnetic field, the spin valve thin-film magnetic element has superior characteristics in which its resistance changes in accordance with a weak magnetic field applied thereto.
FIG. 10 is a schematic cross-sectional view showing the structure of a conventional spin valve thin-film magnetic element observed from a side air bearing surface opposing a recording medium. Shield layers are formed on the upper and the lower sides of the spin valve thin-film magnetic element with gap layers disposed therebetween. The spin valve thin-film magnetic element, the gap layers, and the shield layers constitute a reproducing GMR head. In addition, on the reproducing GMR head, a recording inductive head may be provided. This GMR and inductive head on a trailing edge side portion of a floating type slider detects magnetic fields recorded in a magnetic recording medium, such as a hard disk.
The conventional spin valve thin-film magnetic element shown in FIG. 10 is a bottom type hard bias single spin valve thin-film magnetic element comprising a laminate composed of an antiferromagnetic layer 122, a pinned magnetic layer 123, a non-magnetic conductive layer 124, a free magnetic layer 125; and hard bias layers 129 positioned on the two sides of the laminate.
In this spin valve thin-film magnetic element, the moving direction of a magnetic recording medium, such as a hard disc, is in a Z direction in the figure, the direction of a leakage magnetic field is in a Y direction, and an X1 direction in the figure is a track width direction of the spin valve thin-film magnetic element.
The spin valve thin-film magnetic element shown in FIG. 10 is made of a laminate 120 having an underlying layer 121, the antiferromagnetic layer 122, the pinned magnetic layer 123, the non-magnetic conductive layer 124, the free magnetic layer 125, and a protective layer 127 layered from a bottom side in order. A pair of hard bias layers (permanent magnetic layers) 129 are positioned at the two sides of the laminate 120 and a pair of electrode layers 128 disposed on the hard bias layers 129 respectively. In general, a iron-manganese (Fexe2x80x94Mn) alloy film, a nickel-manganese (Nixe2x80x94Mn) alloy film, or a platinum-manganese (Ptxe2x80x94Mn) alloy film can be used for the antiferromagnetic layer 122. A nickel-iron (Nixe2x80x94Fe) alloy film can be used for the pinned magnetic layer 123 and the free magnetic layer 125. A copper (Cu) film can be used for the non-magnetic conductive layer 124. A cobalt-platinum (Coxe2x80x94Pt) alloy film can be used for the hard bias layers 129. A chromium (Cr) film or a tungsten (w) film can be used for the electrode layers 128. In addition, the underlying layer 121 and the protective layer 127 can be made of a tantalum (Ta) film. In this spin valve, a magnetic recording track width Tw is determined by the width of the upper surface of the laminate 120.
The magnetization of the pinned magnetic layer 123 is placed in a single domain state in the Y direction (the direction of the leakage magnetic field from the recording medium, the height direction), as shown in FIG. 10, by the exchange anisotropic magnetic field generated by the exchange coupling at the interface with the antiferromagnetic layer 122. In addition, the magnetization of the free magnetic layer 125 is aligned in a direction opposite to the X1 direction by the influence of the bias magnetic field of the hard bias layers 129. That is, the magnetization of the pinned magnetic layer 123 and the magnetization of the free magnetic layer 125 are aligned perpendicular to each other.
In this spin valve thin-film magnetic element, a sense current is applied to the pinned magnetic layer 123, the non-magnetic conductive layer 124, and the free magnetic layer 125 from the electrode layers 128 formed on the hard bias layers 129. The leakage magnetic field is applied from the magnetic recording medium. When the magnetization of the free magnetic layer 125 is changed from the direction opposite to the X1 direction to the Y direction due to the relationship of the change in magnetization direction of the free magnetic layer 125 and the fixed magnetization direction of the pinned magnetic layer 123, the electrical resistance is changed (this change is called magnetoresistance (MR) effect), whereby the leakage magnetic field from the recording medium is detected by a change in voltage in accordance with the change in electrical resistance. In the spin valve thin-film magnetic element described above, the rate of change in resistance by an applied external magnetic field is approximately 8%.
For a recording medium, such as a hard disc, a higher recording density can be required. However, to improve the recording density, the magnetic recording track width can be decreased. That is, a narrower track can be required for the spin valve thin-film magnetic element. When the magnetic recording track width Tw is decreased, the track width for detecting an external magnetic field is decreased, and hence, the change in resistance (xcex94R) by the GMR effect is decreased. Consequently, the detection sensitivity of the spin valve thin-film magnetic element is decreased, and a problem may arise in which a higher recording density is difficult to achieve. Accordingly, there is a need for a spin-valve thin film magnetic element having an 8% rate of change of resistance that has an improved detection sensitivity. In addition to the narrower track, there is a need for an improved sensitivity without increasing a gap size, i.e., without increasing the dimension in the Z direction shown in FIG. 10.
A spin valve thin-film magnetic element comprises a substrate; an antiferromagnetic layer disposed on the substrate, and a pinned magnetic layer disposed on the antiferromagnetic layer. Preferably, the magnetization direction of the pinned magnetic layer is fixed by an exchange coupling magnetic field with the antiferromagnetic layer. A non-magnetic conductive layer is positioned between the pinned magnetic layer and a free magnetic layer such that the magnetization direction of the free magnetic layer is aligned in a direction substantially perpendicular to the magnetization direction of the pinned magnetic layer. A pair of electrode layers supply a sense current to the pinned magnetic layer, the non-magnetic conductive layer, and the free magnetic layer and a bias layer to align the magnetization direction of the free magnetic layer in the direction substantially perpendicular to the magnetization direction of the pinned magnetic layer. A specular-reflection layer is positioned further from the non-magnetic conductive layer than the free magnetic layer which increases the free mean paths of conduction electrons by a specular effect. In a preferred embodiment, the film thickness of the free magnetic layer is preferably in the range of about 15 to about 45 xc3x85.
The antiferromagnetic layer preferably comprises one of an Xxe2x80x94Mn alloy and a Ptxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy, in which X is one element selected from the group consisting of platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), and osmium (Os), and Xxe2x80x2 is at least one element selected from the group consisting of Pd, chromium (Cr), Ru, nickel (Ni), Ir, Rh, Os, gold (Au), silver (Ag), neon (Ne), argon (Ar), xenon (Xe), and krypton (Kr).
The specular-reflection layer preferably comprises an insulating material generating an energy gap having a high probability of producing specular reflection which conserves spin states of the conduction electrons. As the insulating material, an oxide, such as xcex1-Fe2O3, or NiO, or a half-metal Heusler alloy may be used. The film thickness of the specular-reflection layer is preferably in the range of about 10 to about 400 xc3x85, and more preferably, in the range of about 10 to about 200 xc3x85. The layers may also be disposed on a substrate in the following order, the antiferromagnetic layer, the pinned magnetic layer, the non-magnetic conductive layer, the free magnetic layer, and the specular-reflection layer.
In one preferred embodiment, the free magnetic layer and the specular-reflection layer may be separated by a back layer that preferably comprises a material selected from the group consisting of Au, Ag, and Cu. The thickness of the back layer is preferably in the range of about 5 to about 15 xc3x85.
Preferably, the pinned magnetic layer comprises a multilayer film and at least one layer of the multilayer film comprise a half-metal Heusler alloy. In addition, the half-metal Heusler alloy preferably comprises at least NiMnSb or PtMnSb, and the layer comprising the half-metal Heusler alloy may be a monolayer film or a multilayer film.
The pinned magnetic layer may comprise a first pinned magnetic layer, a second pinned magnetic layer, and a non-magnetic interlayer positioned therebetween. The first and the second pinned magnetic layers may be in a ferrimagnetic state in which the magnetization directions are about 180xc2x0 out of phase with each other.
The pair of electrode layers may be located near at least two sides of the free magnetic layer, non-magnetic conductive layer, and pinned magnetic layer in the film surface direction thereof. The pair of electrode layers may also be located further from the substrate than the antiferromagnetic layer.
Preferably, at least the antiferromagnetic layer, the pinned magnetic layer, the free magnetic layer, and the specular-reflection layer may comprise a laminate, and the pair of electrode layers is preferably provided near the two sides of the laminate. Preferably, the pair of electrode layers extend toward the laminate and are in direct contact with the free magnetic layer or back layer.
Furthermore, preferably a spin valve thin-film magnetic element comprises a substrate, an antiferromagnetic layer formed on the substrate, and a pinned magnetic layer in contact with the antiferromagnetic layer. Preferably, the magnetization direction of the pinned magnetic layer is fixed by an exchange coupling magnetic field with the antiferromagnetic layer. A non-magnetic conductive layer is preferably positioned between the pinned magnetic layer and a free magnetic layer, in which the magnetization direction of the free magnetic layer is aligned in a substantially perpendicular direction to the magnetization direction of the pinned magnetic layer. A pair of electrode layers preferably supply a sense current to the pinned magnetic layer, the non-magnetic conductive layer, the free magnetic layer, and a bias layer aligning the magnetization direction of the free magnetic layer in a substantially perpendicular direction to the magnetization direction of the pinned magnetic layer. Preferably, the pinned magnetic layer is a multilayer film, and at least one layer of the multilayer film comprises a half-metal Heusler alloy.
Preferably a thin-film magnetic head is provided with the spin valve thin-film magnetic element described above. Since the specular-reflection layer is positioned further from the non-magnetic conductive layer than the free magnetic layer, which increases the free mean paths of the conduction electrons by a specular effect, the free mean paths of the positive spin conduction electrons (spin-up conduction electrons) are increased which contributes to the magnetoresistance effect. Hence, a high rate of change in resistance (xcex94R/R) in the spin valve thin-film magnetic element can be attained. Preferably, a high recording density can be achieved.
The film thickness of the free magnetic layer is preferably in the range of about 15 to about 45 xc3x85. A free magnetic layer having a thickness of less than about 15 xc3x85 is not preferable to the preferred embodiment since the free magnetic layer is difficult to form as a soft magnetic thin-film, a sufficient magnetoresistance effect cannot be obtained, and in addition, the rate of change in resistance is decreased due to the presence of conduction electrons which perform diffusive scattering and no specular reflection described later.
In addition, a free magnetic layer having a thickness of more than about 45 xc3x85 is also not preferable since spin-up conduction electrons are increased which are scattered before reaching the specular-reflection layer, and hence, the ratio of the rate of change in resistance improved by the specula effect is decreased.
In the spin valve thin-film magnetic element described above, the antiferromagnetic layer may comprise an alloy comprised of manganese (Mn) and at least one element selected from the group consisting of Pt, Pd, Rh, Ru, Ir, Os, Au, Ag, Cr, Ni, Ne, Ar, Xe, and Kr, or may comprise an alloy represented by the formula Xxe2x80x94Mn in which X is one element selected from the group consisting of Pt, Pd, Ru, Ir, Rh, and Os, and in which X is preferably in the range of about 37 to about 63 atomic percent. In addition, in the spin valve thin-film magnetic element described above, the antiferromagnetic layer may comprise an alloy represented by the formula Ptxe2x80x94Mnxe2x80x94Xxe2x80x2 in which Xxe2x80x2 is at least one element selected from the group consisting of Pd, Cr, Ru, Ni, Ir, Rh, Os, Au, Ag, Ne, Ar, Xe, and Kr, and in which Xxe2x80x2+Pt is preferably in the rage of about 37 to about 63 atomic percent.
Accordingly, when an antiferromagnetic layer is used which comprises an alloy represented by the formula Xxe2x80x94Mn or an alloy represented by the formula Ptxe2x80x94Mnxe2x80x94Xxe2x80x2, compared to a spin valve thin-film magnetic element having an antiferromagnetic layer composed of a NiO alloy, a Fexe2x80x94Mn alloy, a Nixe2x80x94Mn alloy, or the like, a spin valve thin-film magnetic element can be produced having superior characteristics, such as a strong exchange coupling magnetic field, a high blocking temperature, and a superior corrosion resistance. Since the preferred specular-reflection layer comprises an insulating material generating an energy gap having a high probability of producing specular reflection which conserves spin states of conduction electrons, the rate of change in resistance can be improved by the specular effect described later.
As an insulating material forming the specular-reflection layer described above, there may be oxides, such as xcex1-Fe2O3, NiO, CoO, Coxe2x80x94Fexe2x80x94O, Coxe2x80x94Fexe2x80x94Nixe2x80x94O, Al2O3, Alxe2x80x94Qxe2x80x94O in which Q is at least one element selected from the group consisting of boron (B), silicon (Si), nitrogen (N), titanium (Ti), vanadium (V), Cr, Mn, iron (Fe), cobalt (Co), and Ni, and Rxe2x80x94O in which R is at least one element selected from the group consisting of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W; nitrides, such as Alxe2x80x94N, Alxe2x80x94Qxe2x80x94N in which Q is at least one element selected from the group consisting of B, Si, O, Ti, V, Cr, Mn, Fe, Co, and Ni, and Rxe2x80x94N in which R is at least one element selected from the group consisting of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W; and the like.
When an antiferromagnetic material, such as xcex1-Fe2O3 or NiO, is used as the specular-reflection layer, the specular-reflection layer may also be used as the whole bias layer or a part thereof.
As an insulating material for forming the specular-reflection layer, a half-metal Heusler alloy may also be used, and the specular-reflection layer may be a monolayer or a multilayer comprised of a half-metal Heusler alloy comprising at least one of NiMnSb and PtMnSb. When these materials are used, a sufficient potential barrier between the specular-reflection layer and a layer adjacent thereto can be formed, and as a result, a sufficient specular effect can be obtained. In addition, the film thickness of the specular-reflection layer is preferably in the range of about 10 to about 400 xc3x85, and more preferably, in the range of about 10 to about 200 xc3x85.
A specular-reflection layer having a thickness of less than about 10 xc3x85 is not preferable since a continuous and uniform oxide film having a crystalline structure capable of forming a potential barrier cannot be obtained. As a result, the detection sensitivity is decreased, and hence, the reproducing output characteristics of the spin valve thin-film magnetic element are degraded.
In addition, a specular-reflection layer having a thickness of more than about 400 xc3x85 is not preferable since the specular-reflection layer serves as an antiferromagnetic layer, and as a result, an unexpected exchange coupling magnetic field (Hex) may be generated. Furthermore, when a thin-film magnetic head is formed, it is not preferable since the shield distance, i.e., a reproducing gap, is excessively increased, and as a result, the resolution of the head is degraded.
Since the back layer comprised of a non-magnetic conductive material selected from the group consisting of Au, Ag, and Cu is provided between the free magnetic layer and the specular-reflection layer, the mean free paths of positive spin (spin-up) conduction electrons are increased which contribute to the magnetoresistance effect. Consequently, a high rate of change in resistance (xcex94R/R) can be obtained in the spin valve thin-film magnetic element by a spin filter effect, and hence, a high recording density can be achieved.
The film thickness of the back layer is preferably in the range of about 5 to about 30 xc3x85, and more preferably, in the range of about 5 to about 15 xc3x85. A back layer having a thickness of less than about 5 xc3x85 is not preferable since the effect of increasing the free mean paths of positive (+) spin electrons is decreased. That is, the spin filter effect is decreased.
In addition, a back layer having a thickness of more than about 30 xc3x85 is not preferable since the ratio of a sense current shunting to the back layer composed of a non-magnetic conductive material is increased. Hence, a sense current flowing in the vicinity of the interface of the free magnetic layer and the non-magnetic conductive layer is decreased which can be needed for obtaining the GMR effect. That is, due to an increase in shunt loss, a high rate of change in resistance (xcex94R/R) is difficult to obtain.
Since the pinned magnetic layer is preferably comprised of a multilayer film, and at least one layer thereof is a monolayer or a multilayer comprised of a half-metal Heusler alloy comprising at least one of NiMnSb and PtMnSb, a specular effect can be obtained in a part of the pinned magnetic layer as is the case of the specular-reflection layer. Consequently, a higher rate of change in resistance (xcex94R/R) can be obtained in the spin valve thin-film magnetic element by an increase in free mean paths of the conduction electrons.
Since a ferromagnetic half-metal alloy, such as NiMnSb, or PtMnSb, is disposed between an upper and a lower ferromagnetic layer comprising the pinned magnetic layer, the magnetizations of the ferromagnetic layers in the vertical direction are in the same direction, the multilayer film behaves as if a monolayer film does although the multilayer film is actually a three-layered structure. Hence, stable magnetic characteristics can be obtained. Accordingly, a specular effect can be obtained in the state described above, and as a result, the rate of change in resistance can be improved.
In addition, a synthetic-ferri-pinned type spin valve thin-film magnetic element may be formed in which the pinned magnetic layer is formed of a first pinned magnetic layer and a second pinned magnetic layer with a non-magnetic interlayer provided therebetween and in which the magnetization directions of the first and the second pinned magnetic layers are antiparallel to each other so that the pinned magnetic layer is placed in a ferrimagnetic state. Accordingly, the exchange coupling magnetic field (an exchange anisotropic magnetic field) Hex generated at the interface of the antiferromagnetic layer and the first pinned magnetic layer can be increased. One of the first and the second pinned magnetic layers serves to fix the magnetization of the other pinned magnetic layer in an appropriate direction, and hence, the entire pinned magnetic layer is conserved in a very stable state.
In addition, when a spin valve thin-film magnetic element is formed having a pinned magnetic layer comprised of a first and a second pinned magnetic layers with a non-magnetic interlayer provided therebetween, the magnetostatic coupling fields of the first and the second pinned magnetic layers can counteract the demagnetizing field (the dipole magnetic field) by the fixed magnetization of the pinned magnetic layer. Accordingly, the influence of the demagnetizing field, generated by the fixed magnetization of the pinned magnetic layer, to the direction of the rotatable magnetization of the free magnetic layer can be decreased. Preferably, a layer comprised of the half-metal Heusler alloy described above may be provided at the non-magnetic conductive layer side than the non-magnetic interlayer. That is, the layer described above may be provided in contact with the second pinned magnetic layer or may be provided therein. As a result, a specular effect can be additionally obtained at a side further from the specular-reflection layer than the free magnetic layer. Hence, the rate of change in resistance can be increased.
The pair of electrode layers may be provided at least two sides of the free magnetic layer, the non-magnetic conductive layer, and the pinned magnetic layer in the film surface direction and may be disposed further from the substrate than the antiferromagnetic layer. As a result, the ratio of a sense current supplied in the vicinity of the free magnetic layer exhibiting the GMR effect can be increased without flowing through the antiferromagnetic layer and the bias layer, which have higher resistances compared to the free magnetic layer and the non-magnetic conductive layer. Hence, the rate of change in magnetic resistance in the spin valve thin-film magnetic element can be improved.
In addition, since a sense current can be supplied in the vicinity of the free magnetic layer from the electrode layers while conserving the single domain state of the free magnetic layer, side reading can be prevented, and a higher magnetic recording density can be more effectively achieved.
The principle of the giant magnetoresistance effect in the spin valve thin-film magnetic element will be described briefly. For the purposes of this description, the back layer and the specular-reflection layer are not in contact with the non-magnetic conductive layer adjacent to the free magnetic layer.
When a sense current is supplied to the spin valve thin-film magnetic element, conduction electrons can primarily move in the vicinity of the non-magnetic conductive layer having a low electrical resistance. In conduction electrons, it is highly probable that a substantially equal number of spin-up conduction electrons and spin-down conduction electrons are present.
The rate of change in magnetic resistance in the spin valve thin-film magnetic element has a positive relationship with the difference in free mean path between these two types of conduction electrons.
The spin-down conduction electrons are generally diffused at the interface of the non-magnetic conductive layer and the free magnetic layer regardless of the direction of an applied external magnetic field. The probability of moving into the free magnetic layer is maintained at a lower level, and the free mean paths of the spin-down conduction electrons are relatively short compared to those of the spin-up conduction electrons.
On the other hand, the spin-up conduction electrons have a higher probability of moving from the non-magnetic conductive layer to the free magnetic layer when the magnetization directions of the free magnetic layer and the pinned magnetic layer are parallel to each other by an external magnetic field. Hence, the free mean paths are increased. In addition, as the magnetization direction of the free magnetic layer rotates by an external magnetic field from a direction parallel to the magnetization of the pinned magnetic layer, the probability of scattering at the interface of the non-magnetic conductive layer and the free magnetic layer is increased. As a result, the free mean paths of the spin-up conduction electrons are decreased.
As described, by an application of an external magnetic field, the free mean paths of the spin-up conduction electrons can be changed compared to those of the spin-down conduction electrons. As a result, the difference in the free mean path therebetween is significantly changed. Accordingly, the resistivity is changed, and the rate of change in magnetic resistance (xcex94R/R) of the spin valve thin-film magnetic element is increased.
When the back layer is connected to the free magnetic layer, the spin-up conduction electrons moving in the free magnetic layer can move into the back layer, and the free mean paths of the spin-up conduction electrons can be increased in proportion to the thickness of the back layer. Accordingly, a spin filter effect can be obtained, the difference in free mean path between the conduction electrons is increased, and the rate of change in magnetic resistance (xcex94R/R) in the spin valve thin-film magnetic element can be improved.
In addition, when the specular-reflection layer is formed not in contact with the non-magnetic conductive layer adjacent to the free magnetic layer, the specular-reflection layer forms a potential barrier at the interface with the free magnetic layer and can reflect the spin-up conduction electrons moving in the free magnetic layer while conserving the spin states. Accordingly, the free mean paths of the spin-up conduction electrons can be increased, that is, a specular effect can be obtained. As a result, the difference in free mean path between the spin dependent conduction electrons is increased, and hence, the rate of change in magnetic resistance in the spin valve thin-film magnetic element is improved.
Furthermore, when the specular-reflection layer is formed on the surface opposite to the free magnetic layer of the back layer, the spin filter effect and the specular effect can be obtained simultaneously, and hence, the free mean paths of the spin-up conduction electrons can be increased. That is, the difference in free mean path between the spin dependent conduction electrons can be increased, and the rate of change in magnetic resistance can be improved.
The difference of the free mean paths by the back layer and the specular-reflection layer can be obtained when the free magnetic layer is relatively thin, and simultaneously, by controlling the film thicknesses of the layers that increase the free mean paths, the magnetization of the free magnetic layer is controlled. Hence, detection sensitivity and output characteristics of a spin valve thin-film magnetic element having a narrower track can be improved.
The spin valve thin-film magnetic element may comprise a bottom type single spin valve formed in the following order and comprising at least an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic conductive layer, a free magnetic layer, and a vertical bias layer on a substrate side or surface. Alternatively, the spin valve thin-film magnetic element may comprise a top type single spin valve formed in the following order and comprise at least a vertical bias layer, a free magnetic layer, a non-magnetic conductive layer, a pinned magnetic layer, and an antiferromagnetic layer on a substrate or surface.
In addition, when a spin valve thin-film magnetic element is comprised of a free magnetic layer comprised of two films with a non-magnetic interlayer provided therebetween, the exchange coupling magnetic field is preferably generated between the two films comprising the free magnetic layer. Preferably, the free magnetic layer is in a ferrimagnetic state, and the magnetization direction of the free magnetic layer rotates in response to an external magnetic field.


The proper operation of an NDIR toxic gas sensor can be checked by using a non-toxic gas that has an absorption band that overlaps the absorption band used for measuring the toxic gas. The NDIR sensor cannot distinguish which of the two gases is responsible for causing the observed absorption of radiation in the sensor. Since detectors of toxic gases typically operate at low concentration levels, the extent of overlap between the absorption band of the toxic gas and of the non-toxic gas may be relatively small, since a larger concentration of the non-toxic gas can be used with no ill effects. The method may be applied to sensors for detecting carbon monoxide or methane for example.

Field of the Invention
The present invention relates to a method for determining whether a toxic gas sensor is functioning properly at any particular time. Surprisingly, no toxic gas is needed to perform the test.
Toxic gas sensors are widely used for sensing a build-up in the concentration of a toxic gas, for example, carbon monoxide, methane, hydrogen sulfide, and others, to protect the lives of persons who are exposed to the toxic gas. It is essential that the toxic gas sensor operate reliably, and to this end it is desirable to test the operation of the sensor from time to time.
At the completion of the manufacturing process, the sensor is calibrated by exposing it to an accurately controlled concentration of the toxic gas and noting the output reading of the sensor. At this point there is no doubt that the sensor is functioning properly and can be depended upon to save lives.
Thereafter, the sensor is transported, handled, and put into daily use where it is exposed to a number of environmental stresses. After a period of such use, the sensors may be found to have changed due to aging, due to chemical reactions with environmental elements such as moisture, particulates, smoke, various gases, insects, soot, and oil vapors, and due to chemical instabilities. In most instances, these environmental stresses affect the functioning and sensitivity of the sensors. If the sensor ceases to operate continuously, or if its sensitivity becomes sufficiently degraded, the sensor can no longer be relied on to protect the lives of those who are depending on it. Thus, it is seen to be highly desirable to provide a simple and easy method for testing the toxic gas sensors from time to time, to assure that they are continuing to operate properly.
Initially, one might consider the possibility of providing to the users of the sensors actual samples of the toxic gases for performing this periodic testing. However, upon further consideration this does not seem to be a good solution because frequently the users of the sensors are not familiar with proper techniques for handling the toxic gases, and they normally would not have appropriate apparatus for handling the toxic gases, so that there would be a large risk involved. Of course, some toxic gases are more deadly than others, but an element of risk still remains.
The present invention is directed to a method for testing the operation of a toxic gas sensor without using any toxic gas.

Functional testing method for toxic gas sensors


Vacuum cleaning apparatus having a rotary brush situated at an air intake opening in a housing has a configuration which enables efficient cleaning of edge portions of a floor that are adjacent to a wall or other vertical surface. A cleaning head portion of the housing has intersecting sidewalls which extend at right angles to each other enabling one sidewall to face the edge of a floor while the other sidewall faces the lower edge of an adjacent wall. The air intake opening is angled to extend into both of the angled intersecting sidewalls of the cleaning head. The rotary brush carries bristles which protrude through the air intake opening at both of the sidewalls of the cleaning head and at the intersection between the sidewalls.

This invention relates to vacuum cleaning apparatus for cleaning floors or other surfaces. More particularly the invention relates to vacuum cleaning apparatus for cleaning edge regions of floors that are adjacent to walls or other vertically extending surfaces.
Vacuum cleaners have a motor driven rotary fan which draws air into an intake opening in a housing to create suction which draws dust and other loose material into the housing. The cleaning effect is enhanced if a rotating brush is present at the air intake opening. The brush loosens dust or other material that may tend to cling to the floor or to carpets or rugs which are present on the floor.
The air intake openings of commercially available vacuum cleaners which have a rotary brush do not extend all of the way to the side surfaces nor to the front surface of the vacuum cleaner housing. Portions of the housing bound the intake opening at the sides and at the front of the opening in order to define the air flow path and to channel the air flow towards the brush. Space adjacent to the ends of the intake opening is occupied by bearings for supporting the rotary brush. As a result, the air intake opening cannot be positioned directly over the extreme edge regions of the floor where the floor contacts a wall or other vertical surface. A rotary brush which is situated within the air intake opening cannot be abutted directly against the wall. Consequently, the standard vacuum cleaner does not clean the extreme edges of a floor in an efficient manner at locations where the floor meets a wall or other vertical surface.
In some instances, the problem is addressed by providing an air intake accessory which attaches to a flexible vacuum hose that bypasses the main air intake opening and rotary brush. This cleans the edge regions by suction only. Suction alone does not clean as effectively as suction combined with a brushing action. Some prior vacuum cleaner designs have supplemental brushes at the sides of the vacuum cleaner housing or brushes with angled bristles at the ends which extend away from the air intake opening towards the sides of the housing. Supplemental brushes or angled bristles of this kind are not directly within the air intake opening of the vacuum cleaner and are at a location where the suction effect is diminished or absent. Brushing in the absence of a strong suction air flow does not provide the most effective cleaning.
The present invention is directed to overcoming one or more of the problems discussed above.
In one aspect the present invention provides vacuum cleaning apparatus having a housing at which an air intake opening is situated and having a rotary brush disposed at the opening. The housing has intersecting first and second sidewalls which extend substantially at right angles to each other enabling one of the sidewalls to face a horizontally extending edge of a floor while the other sidewall faces a lower portion of a vertically extending wall. The air intake opening has first and second adjoining portions which extend substantially at right angles to each other, the first portion of the air intake opening being in the first sidewall of the housing and the second portion of the air intake opening being in the second sidewall of said housing. The rotary brush has bristles which protrude through the first portion of the air intake opening and also bristles which protrude through the second portion thereof.
In another aspect of the invention, vacuum cleaning apparatus includes a housing having an air intake region with intersecting first and second sidewalls that extend at right angles to each other enabling the air intake region to be fitted against an edge of a floor that is adjacent to a vertical wall. The air intake region of the housing has a right angled air intake opening situated at the intersecting first and second sidewalls and which extends across the intersection thereof. A rotary brush is disposed in the housing adjacent to the air intake opening and has bristles which protrude through the air intake opening at each of the first and second sidewalls and at the intersection thereof.
The invention enables efficient vacuum cleaning of the margins of a floor which are adjacent to a wall or other vertical surface. The vacuum cleaning apparatus has an air intake structure and a rotary brush which are configured to fit into the right angled junction of the floor and vertical wall. The air intake opening is angled to extend horizontally across the edge region of the floor and then upward along a lower edge of the wall. The rotary brush at the air intake opening has sides which are angled relative to each other enabling bristle contact with the edge region of the floor and also with the lower edge of the wall.
The invention, together with further objects and advantages thereof, may be further understood by reference to the following detailed description of the invention and by reference to the accompanying drawings.


A system for providing high-resolution display for a matrix output device, such as a Photo-Multiplier Tube (PMT) matrix, that requires a substantially less number of amplifiers than prior readout systems. A resistor matrix is coupled directly to the outputs of a matrix output device. The outputs in each row in the matrix are combined and amplified with an amplifier that is at an end of each row. Similarly, the outputs in each column of the matrix are combined and amplified with an amplifier at an end of each column. The amplifiers at the end of each row and column also provide conversion of the signals from a current to a voltage. The converted and amplified signals are then processed, using a simple yet accurate algorithm such as center of gravity interpolation, to determine location and other information. The determined information may relate to detection of photons on the PMTs, for example, and is provided as an output signal from the processing circuitry. The output signal from the processing circuitry can be sent to a display device such as a video monitor for display and further analysis of the determined information. The present imaging readout system provides substantial savings in the cost of production and operation of PMT systems, which typically have thousands of outputs requiring amplification for readout.

The present invention relates generally to matrix output devices, and more specifically to a readout system for a matrix output device, that requires substantially less amplifiers than traditional readout systems.
A Position Sensitive Photo-Multiplier Tube (PSPMT) is a photosensitive matrix output device that converts light photons into electrical currents. The main components of a PSPMT are an input window, a photocathode, focusing electrodes, dynodes and an anode. The photocathode is used for converting incoming light (photons) into electrons. These photoelectrons, which are a product of the photoelectric effect, are directed by the potential of focusing electrodes towards dynode stages. The dynodes are used to multiply the electrons by the process of secondary electron emission. Electron gains of 103 to 108 are common and depend on the number of dynode stages and interdynode potentials of the PSPMT.
The voltages that create the electrostatic fields between the photocathode, the focusing electrodes and the dynodes are delivered from a single high-voltage stable power supply and a voltage divider. The divider is a common part of a PMT base. The design of the divider circuit is crucial to getting the best performance from PMT. Series-regulator type high voltage power supplies optimized for photomultiplier tubes are well known in the art. Other components found in or required by scintillation cameras are described in xe2x80x9cPhotomultiplier Tube, Principle to Applicationxe2x80x9d by Hamamatsu Photonics K. K., March 1994, which is incorporated herein by reference.
The output of a photomultiplier tube is a current, while the external signal processing circuits are usually designed to handle a voltage signal. Therefore, the current output must be converted into a voltage signal by a current to voltage converter. Further, the current that is output from a PMT anode is very small, especially in low light level detection and photon counting applications. An operational amplifier can be used to both convert the anode output current to a voltage and accurately amplify the resulting voltage. Typically this operational amplifier is powered by a source that is separate from the high voltage power source for the dynode stages of the PMT. This is done to insure the stability of the power supply to the dynodes. The voltage supplied to each dynode stage must be extremely stable or the PMT output will be adversely affected.
Typically, a PMT provides reliable, stable gain for some hundreds or thousands of hours, then its stability decreases as a function of the total charge handled. The decreased stability is primarily a result of dynode degradation. The dynode stages of a PMT are worn down more quickly when higher voltages, higher gain and higher anode currents are used. The use of very high voltages across the dynode stages provides a PMT output that may not need amplification. However, this leads to frequent replacement of the PMT""s.
The present system provides accurate, inexpensive readout of the output signals of matrix output devices, such as Position Sensitive Photo-Multiplier Tubes (PSPMT). The system provides a reduction in the number of output channels without a loss of position information. PSPMT""s are used in many imaging devices that are in use and under development the medical field and other commercial applications.
PSPMT""s such as Phillips 1702, 1722 and 1752, traditionally require a 64-channel readout. The present system provides a significant reduction of the number of analog electronic channels necessary for complete X and Y coordinate information readout. The channel reduction for the above mentioned PSPMT""s is from 64 down to only 16 required analog outputs. By reducing the number of channels that need to be read, the entire read out system can be significantly simplified. This will lead to reduced cost and smaller packaging. A reduction in size is particularly important in applications such as inter-operative probes, where smaller devices have greater utility. The present read out system provides cost and size savings without any loss in information integrity.
The present system provides separate X and Y coordinates from the PSPMTs and can use several different methods such as, charge division based signal processing, center of gravity interpolation and delay line readout to determine location and other information. In the preferred embodiment, center of gravity interpolation is used. The system includes the small amount of hardware required to execute the center of gravity calculations. Preferably, analog hardware is used. However, digital circuitry may easily be substituted to perform the center of gravity calculations.
The present readout system includes a resistor matrix connected directly to the PSPMTs matrix outputs. Matrix output devices can be described as having X number of rows and Y number of columns. Each row and column may contain 32, 64 or more PMT outputs. However in the present system, only one output is analyzed for each row and one for each column. The PSPMT outputs are currents that require termination with low impedance amplifiers. The present resistor matrix is connected directly to the low impedance amplifiers. Output signals from each resistor in the matrix are sent along X and Y signal paths that terminate at an end of each of the rows and columns. These row and column signals are the only output signals that are further processed in the present system to determine location/coordinate information. The X and Y output signals are processed using center of gravity interpolation to determine the X to Y separation, in the preferred embodiment. Each resistor of the resistor matrix is of the same value and the ratio of the resistors value to the input amplifiers impedance value are used to determine coordinate information from the PSPMT outputs.
In the preferred embodiment, center of gravity interpolation is used to convert 2-D coordinate PSPMT outputs into X and Y outputs via a directly coupled resistor matrix. In alternative embodiments, different coordinate determination methods are used such as, charge division and delay line readout. In the charge division embodiment, the amplifier output signals are connected as independent X and Y outputs to resistor chains. In the delay line readout embodiment, the amplifier output signals are connected to a delay line. In all embodiments the resistor values are set according to the application. Further, analog data processing circuitry is preferred however, can be replaced by digital processing circuitry.
The present system provides high-resolution display for a matrix output device, such as a Photo-Multiplier Tube (PMT) matrix1 with a substantially less number of amplifiers than prior readout systems. In a typical example, the present readout system can replace a traditional system that requires 64 amplifiers with a system that requires only 16 amplifiers. And the present 16-amplifier system delivers the same or better resolution as the traditional readout system. A resistor matrix is coupled directly to the outputs of a matrix output device. The outputs in each row in the matrix are combined and amplified with an amplifier that is at one end of each row. Similarly, the outputs in each column of the matrix are combined and amplified with an amplifier at one end of each column. The amplifiers at the end of each row and column also provide conversion of the signals from a current to a voltage. The converted and amplified signals are then processed, using a simple yet accurate algorithm such as center of gravity interpolation, to determine location and other information. The determined information may relate to detection of photons on the PMTs, for example, and is provided as an output signal from the processing circuitry. The output signal from the processing circuitry can be sent to a display device such as a video monitor for display and further analysis of the determined information. The present imaging readout system provides substantial savings in the cost of production and operation of PMT systems, which typically have thousands of outputs requiring amplification for readout.

Southeastern University Research Assn. Inc.


A camera carrying device having a support plate with a slot in the plate with the slot having a closed end and an open end joined by an intermediate section, with the intermediate section of lesser width than the closed end, an angle plate having first and second arms, with one of the arms disposed at an angle to the other, a first camera engaging stud carried in the first arm, and a second slot engaging stud carried in the second arm, with the second stud having an end section and an intermediate section, with the second stud end section larger than the slot, with the second stud intermediate section slideable along the slot intermediate section, and with the second stud intermediate section non-circular in cross-section.

This invention relates to camera carrying devices, and in particular to a new and improved camera carrying device which permits the carrying of the camera without requiring grasping of the camera, and which permits quick and easy connecting and disconnecting of the camera to and from the support.
Cameras are carried in a variety of modes, including a case with a shoulder strap or belt, a neck strap or a hand strap for the camera, a handle directly attached to the camera, and a chest strap or chest harness.
These prior arrangements have a variety of disadvantages. Some of them are bulky, some require connecting and disconnecting of the straps and/or buckles, some require opening and closing of flaps, some are loosely arranged and permit the camera to swing relatively freely, some require continuous manual grasping of the camera.
It is an object of the present invention to provide a new and improved camera carrying device consisting essentially of two components, one attached to the camera and one attached to the wearer, typically to a conventional belt. A further object of the invention is to provide such a camera carrying device which will hold the camera firmly to the user's body, while at the same time permitting removal and installation by a simple single-handed motion.
Other objects, advantages, features and results will more fully appear in the course of the following description.


A packaging cover for bristles of a cleaning apparatus having a base with a neck portion, wherein the bristles are attached to the base. The packaging cover has two webs of flexible sheet material. The packaging cover has a base end and an opposite top end. Both webs are joined at the top end and/or the base end. At least one of the webs has at least one opening near the base end wherein each opening is large enough to accommodate the neck portion of the cleaning apparatus. Both webs have opposing sides which extend between the base end and top end. Both webs are separated from each other along at least a portion of each of the opposing sides.

1. Field of the Invention
This invention relates to a packaging cover which is wrapped around bristles and a base structure, of a cleaning apparatus, such as a broom, a brush, a mop or the like, to which the bristles are attached. The packaging cover is preferably constructed of plastic or paper sheet material on which an advertising or instructional message can be displayed.
2. Description of Prior Art
Conventional packaging covers for brooms, brushes, mops and the like typically have sealed opposing sides, an open top end and an open bottom end. With such conventional packaging covers, because the bristles normally diverge toward the free ends of the bunched bristles, the packaging cover is installed by inserting a handle of the utensil through the open top end and then through the open bottom end, until the top end is positioned at a desired location with respect to the bristles. With sealed or closed sides, a separated or open top end, and a separated or open base end, such conventional packaging covers are easily and undesirably displaced from the desired position.
To overcome the stability problems associated with conventional packaging covers discussed above, a packaging cover with sealed corner areas of the top end of the package was developed. U.S. Pat. No. 3,860,115 teaches such packaging cover. The opposing sides of such packaging cover are closed. Thus, such packaging cover is installed in a manner similar to the installation of other known packaging covers, as discussed above.
U.S. Pat. No. 3,167,178 discloses a paint brush wrapper. An envelope of substantially rectangular configuration has four edges forming two opposing sides, a top and a bottom. Both sheets of material of the envelope are sealed at the top and an adjacent side. At the side which is opposite the sealed side, both sheets of material are unsealed. Along a second edge of the envelope, both sheets are unsealed. A handle of a paint brush is first inserted into the side opening and then through the bottom opening, and the paint brush handle is moved further through the bottom opening until the bristles are enclosed between both sheets of material. A flap of one sheet of the material is used to close off the open side, once the paint brush is inserted within the envelope.
It is apparent that there is a need for a packaging cover which is relatively stable once installed, and which can be conveniently installed on cleaning apparatuses having various bundled shapes of the bristles. With the improved arrangement of bristles on modern cleaning apparatuses, it is necessary to have a packaging cover that can accommodate the various shapes and arrangements of bundled bristles.

Packaging cover for a cleaning apparatus having bristles


An optical disk apparatus having an aberration correcting unit for correcting aberrations generated on the recording surface of an optical disk based on received correcting signals, a servo signal generating unit for generating servo signals based on the reflection lights from the optical disk and predefined parameters, and a birefringence detecting unit that detects the degrees of birefringent portions on the recording surface based on received the servo signals and generates the correcting signals for correcting aberrations according to the detected degrees of the birefringent portions and outputs the correcting signals.

(1.) Field of the Invention
The present invention relates to an optical disk apparatus.
(2.) Description of Related Art
In Japanese Unexamined Patent Application Publication No. 2002-342952, a recording & reproducing apparatus of optical recording media equipped with control units of a focus servo and a tracking servo for aberration correction is disclosed. In addition, in Japanese Unexamined Patent Application Publication No. 2005-332558, an optical disk apparatus equipped with a spherical aberration correcting section that corrects the spherical aberrations generated in optical beams in advance, a focus error detecting unit that detects focus error signals, and a control unit that adjusts the signal amplitudes output from the focus error detecting unit to predefined values after the amounts of spherical aberrations are made equal to predefined amounts by the spherical aberration control unit.
There are cases where the recording surfaces of optical disks on which an optical disk apparatus records data and from which the optical disk apparatus reproduces data have so called birefringent portions. The birefringent portions come into existence owing to internal stresses that are generated during the disk production process. If there are birefringent portions on the recording surface of an optical disk, when laser beams are focused on the recording surface, the patterns of the focused light spots get distorted or blurred so that the amounts of the reflected lights may decrease or improperly change. Such a decrease or change of the amounts of the reflected lights deteriorate reproduced signals and servo signals that are generated with the use of the reflection lights, with the result that the so-called servo control for putting the focused light spots on the tracks of the recording surfaces will get unstable.
In either of the above-mentioned patent documents, however, there are no measures taken to prevent the deteriorations in the quality of reproduced signals or servo signals owing birefringence.


The present disclosure is related to a method of manufacturing an array substrate. The method of manufacturing an array substrate may include forming an auxiliary cathode on a base substrate, forming a layer of magnetic material on a first surface of the auxiliary cathode, forming an emission layer in a display area of the array substrate, a part of the emission layer on the layer of the magnetic material on the first surface of the auxiliary cathode, and removing the part of the emission layer and the layer of magnetic material from the first surface of the auxiliary cathode.

An organic light-emitting diode (OLED) display panel includes organic electroluminescent diodes. Since the OLED display panel contains self-illuminating organic electroluminescent diodes, it does not require a backlight. Furthermore, the OLED display panel has become very popular because of advantages such as high contrast, thin thickness, wide viewing angle, fast response speed, being capable of making flexible panels, wide temperature range, simple structure, and simple process.

Array substrate having a layer of magnetic material, display panel having the same and manufacturing method the same thereof

HEFEI XINSHENG OPTOELECTRONICS TECHNOLOGY CO., LTD.