A thermoplastic silicon-containing polymer, which may be a precursor of SiC, and which can be transformed to a thermosetting polymer by copolymerizing it with a thermosetting perhydropolysilazane or polyborosilazane.

1. Field of the Invention
The present invention relates to a thermosetting copolymer, a silicon carbide-based fiber and processes for producing the same. This thermosetting copolymer is a copolymer of a thermoplastic silicon-containing polymer and perhydropolysilazane or polyborosilazane, and since it exhibits thermosetting property, is able to be converted directly to ceramics by pyrolysis and is useful as precursor polymer of ceramic fibers, ceramic coatings, ceramic binders, etc. This silicon carbide-based fiber is a novel inorganic fiber comprising Si, N and C as the major components and silicon carbide as the main phase, and since they have a high strength, modulus and thermal resistance, is useful as a reinforcement of various composite materials.
2. Description of the Related Art
Silicon carbide is excellent as a structural material and polycarbosilanes, polysilastyrenes, polysilanes, etc., are known as precursor polymers of the silicon carbide (Ceram. Eng. Sci. Proc., 97-8, 1988, p 931-942; and Japanese Unexamined Patent Publication (Kokai) Nos. 51-126300, 52-74000 and 52-112700). Silicon carbide fibers formed by spinning a polycarbosilane followed by curing and firing are known (J. Am. Ceram. Soc., 59, 1976, p 324-327; and Chem. Lett. No. 9, 1975, p 931-934).
Also, polytitanocarbosilane, polyzirconocarbosilane, polydisilylazane, etc., are known as precursors of silicon carbide-based ceramics such as SiC--TiC (U.S. Pat. Nos. 4,340,619, 4,321,970 and 4,482,689 and Japanese Examined Patent Publication (Kokoku) Nos. 2-33734, 2-33733, 61-58086 and 62-61220).
Silicon carbide-based fibers obtained from polytitanocarbosilane and polyzirconocarbosilane are also known (Japanese Unexamined Patent Publication (Kokai) Nos. 56-9209, 57-106718, 57-106719 and 60-99004 or U.S. Pat. Nos. 5,085,819; 4,515,742; 4,063,229; 4,342,715 and 4,399,232).
Polysilazanes and polyborosilazanes, however, are known as precursors of silicon nitride and silicon nitride-based ceramics, and the inventors have disclosed such polymers (Japanese Examined Patent Publication (Kokoku) No. 63-16325). Si--N--C--O--based ceramic fibers obtained by spinning an organic silazane followed by curing and firing are known (Japanese Unexamined Patent Publication (Kokai) Nos. 49-69717, 49-20206 and 57-200210; U.S. Pat. No. 4,482,669; and J. of Appln. Poly Sci., Vol. 27, 3751-61, (1982). Also, we disclosed silicon nitride fibers produced from perhydropolysilazane and containing a lesser amount of carbon (Japanese Unexamined Patent Publication (Kokai) No. 62-125015 or U.S. Pat. No. 4,818,611).
Since the above precursors for silicon carbide or silicon carbide-based ceramics are thermoplastic, a curing step is essential for producing a ceramic product from these precursor polymers. The curing process may be any of known such as thermal oxidation, steam treatment, .gamma.-ray irradiation, electron beam irradiation halogen treatment, ozone treatment, etc. But use of radiation is complicated and dangerous, and further, is inefficient and also causes contamination with impurities. Particularly, oxygen introduced by the thermal oxidation damages the high temperature properties of the obtained ceramics. Further, the ceramics produced from these percursor polymers contain much free carbon and the perhydropolysilazane does not provide silicon carbide ceramics.
Silicon nitride and silicon nitride-based ceramics are candidates for high temperature structural material having an excellent strength and toughness, etc. Since silicon carbide provides a structural material having a higher strength, composites of the silicon nitride or silicon nitride-based ceramics with silicon carbide are effected to provide ceramics having more excellent properties. Further, the micro structure of the derived ceramics can be controlled by doping adequate amount of boron.
Therefore, the object of the present invention is to convert a thermoplastic polymer to a thermosetting polymer, to thereby provide a polymer which can be converted into ceramics without a curing process, more particularly, to provide a polymer useful as a precursor of composite ceramics of silicon carbide and silicon nitride. Another object of the present invention is to provide silicon carbide-based ceramic fibers having a lesser amount of oxygen and free carbon.

Thermosetting copolymers, silicon carbide-based fiber and processes for producing same


A signal processing method and apparatus. According to the signal processing method, phase change processing can be performed on to-be-sent data signals according to a phase status of a data synchronization signal and phase statuses of the to-be-sent data signals, so that phase differences between a majority of to-be-sent data signals in the processed to-be-sent data signals and the data synchronization signal meet a certain condition, thereby reducing a volume of coupling crosstalk, generated by the to-be-sent data signals, on the data synchronization signal and further reducing impact of simultaneously switching noise (SSN) on a system.

A double data rate (DDR) synchronous dynamic random access memory (SDRAM) is a currently most common and universal memory, and may be hereinafter referred to as DDR. Because the DDR has a double data rate function, the DDR currently has been widely applied to electronic devices of all industries.
With the rapid development of hardware and network technologies, a user also has an increasingly higher requirement for encapsulation and integration of a DDR chip and a controller chip. Therefore, in a process of exchanging data between the DDR chip and the controller chip, simultaneously switching noise (SSN) is generated during signal transmission, thereby affecting reliability of a DDR interface.
In the prior art, to reduce impact of SSN on reliability of a DDR interface, usually inductive coupling crosstalk between signals is suppressed, which is implemented by decreasing an input/output (I/O) drive current and by increasing, in a case in which an I/O quantity is unchanged, power source and ground pins of a chip. Although this method can decrease some SSN, effect of decreasing SSN is not obvious. Moreover, increasing power source and ground pins of a chip directly increases a difficulty of board design and production; and decreasing an I/O drive current may also affect a rate of a signal edge, thereby affecting a signal sequence.


Methods, devices, and computer program products for capturing images with reduced blurriness in low light conditions are contained herein. In one aspect, a method of capturing an image is disclosed. The method includes capturing a plurality of first images with a first exposure length. The method further includes aligning each of the plurality of first images with each other and combining the aligned plurality of first images into a combined first image. The method further includes capturing a second image with a second exposure length, wherein the second exposure length is longer than the first exposure length and using the second image to adjust the brightness of the combined first image.

Image capture devices with small physical pixels, such as those in cell phone cameras, are widely used. However, these devices may have difficulty capturing high-quality images in low-light scenarios. For example, one approach to capturing an image in a low-light scenario is to use a long exposure time. However, a long-exposure image may become blurred if the image capture device, such as a handheld phone camera, is in motion. Others have approached this problem by blindly de-blurring a blurred long-exposure image, which requires estimating camera motion and deconvolving the image using the estimated motion. This approach may be computationally difficult, and may also be unsuccessful in creating high-quality images.
Another option is to use a short exposure time, which may reduce blurriness. However, in a low-light scenario, a short exposure time may result in a dark image. In order to brighten this image, the camera sensor gain (ISO) may be increased. However, increasing the ISO of the image in a dark image may result in a noisy image. Another approach to brighten a short-exposure image may be to use flash. However, the flash does not usually help in outdoor scenarios, and flash may also lead to artificial color offsets and decrease the color accuracy in the resulting image.
Accordingly, no camera exposure setting can result in a sharp, bright and noise-free image from a moving camera in a relatively dark scenario.

System and method to capture images with reduced blurriness in low light conditions


Defects, associated with the presence of microbubbles in the photoresist developer solution, have been largely eliminated by providing an apparatus and method whereby the photoresist developer solution, while on standby status in a buffer tank, is maintained at a negative pressure (about minus 0.5 kg/cm.sup.2). This allows any microbubbles, that were introduced into the solution during the course of conveying it to the buffer, to escape. The negative pressure in the buffer during its refill and standby stages is generated by adding a venturi valve to the existing equipment. This keeps the impact on the control software to a minimum and has little or no effect on the cost of the process.

(1) Field of the Invention
The invention relates to the general field of photoresist processing during integrated circuit manufacturing, more particularly to automatic dispensing of photoresist developer.
(2) Description of the Prior Art
In the course of manufacturing semiconductor integrated circuits, extensive use is made of photoresist for masking purposes. The photoresist, after exposure to ultraviolet light through a mask, needs to be developed. In a production environment there will be multiple stations at which photoresist can be developed as well as automatic delivery systems for supplying and dispensing developer solution, as it is needed.
We have observed, with the photoresist developer supply system that we have been using, that certain defects in the developed image may manifest themselves from time to time. Careful examination has revealed that these defects followed the direction of developer solution flow along the wafer surface from its point of dispensation. Further examination has shown that the defects arise from microbubbles in the developer solution. These microbubbles are introduced into the solution during its journey from the chemical room, where the developer is stored in bulk, to the buffer tanks in which the developer is held in readiness for demand by the dispensing stations.
Referring now to FIG. 1, we show there a schematic view of the flow system that we had previously used to bring the developing solution to the wafers. Main entrance pipe 3 is connected to the chemical room (not shown) through several tens of meters of piping. From 3, photoresist developer is directed to buffer tanks 1 and 2 whence they flow to two-way valve 4 which, under external control, directs the liquid to either of its outputs 5 and 6, each of which is connected to a separate dispensing unit. The symbol `P in a circle` represents a diaphragm pump.
The sequence of events whereby alternate buffers are used as sources of photoresist developer is best followed by referring to FIGS. 2 and 3. Block 23 in FIG. 2 is marked as `active` meaning that it is in process of sending liquid to two-way valve 4 (FIG. 1) The time for which it is active corresponds to the width of block 23 and is about 40 minutes. In synchrony with this, we have blocks 24 and 25 that relate to buffer 2. During the time corresponding to block 24, buffer tank 2 is connected to exhaust tank 13 through two-way valve 12. This brings the pressure in buffer 2 to zero (relative to atmospheric pressure) and allows developer solution to flow in from 3 and refill 2. When level sensor 32 signals that buffer 2 is full, valve 12 switches over to a source of inert gas (usually nitrogen) that is maintained at positive pressure (relative to atmosphere) with a view to minimizing possible oxidation of the developer in tank 2. Said positive pressure is then maintained for the period corresponding to block 25 when buffer 2 is said to be in standby mode.
Thus, except for the brief period corresponding to block 24, buffer 2 is always under a positive pressure of about 1 kg/cm..sup.2 This is reflected in FIG. 3 which shows pressure vs. time for the two tanks. During the time that buffer 1 is active (block 23 in FIG. 2) the pressure in it is about 1 kg/cm..sup.2 (curve 33 in FIG. 3). While buffer 2 is refilling (block 24 in FIG. 2) the pressure is reduced to zero (relative to atmospheric) (curve 36) but, once the tank has been filled, the pressure reverts to 1 kg/cm..sup.2 (curve 37) and remains there until it needs to be refilled once more (curve 38 and block 28).
A similar sequence of events, displaced in time so as to be exactly out of phase with tank 2's sequence, takes place for tank 1 (blocks 23, 26, and 27 in correspondence with curves 33, 34, and 35 respectively). Thus, one tank is always active while the other is being filled and then placed on standby status. In all cases, however, except for the brief period of refilling, the pressure in the tanks is positive and it is never negative.

Eliminating microbubbles in developer solutions to reduce photoresist residues

Taiwan Semiconductor Manufacturing Company, Ltd.


A method for managing a pattern object file in a modular test system is disclosed. The method includes providing a modular test system, where the modular test system comprises a system controller for controlling at least one site controller, and where the at least one site controller controls at least one test module and its corresponding device under test (DUT). The method further includes creating an object file management framework for establishing a standard interface between vendor-supplied pattern compilers and the modular test system, receiving a pattern source file, creating a pattern object metafile based on the pattern source file using the object file management framework, and testing the device under test through the test module using the pattern object metafile.

1. Field of Invention
The present invention relates to the field of automated test equipment (ATE) for semiconductor testing. In particular, the present invention relates to a method and system for managing pattern object files in a modular test system.
2. Description of Related Art
In conventional ATE systems, the contents of pattern object files are closely tied to vendor-specific proprietary hardware. No standard has existed for integrating pattern object files in a test system to work with various vendors' proprietary hardware. In addition, module vendors do not want to publicly share their proprietary formats, which make it difficult to develop a general pattern object format. Moreover, enforcing a common format may create additional overhead that could lead to compromises in the efficiency of pattern use. As a result, there is no common object file format for pattern data to be used among various module vendors. Module vendors have to provide their own pattern compilers to compile pattern source files into pattern object files. This has led to a cumbersome cycle of translating pattern files each time a vendor chooses to use a different vendor's test equipment. It is desired to overcome these disadvantages.
Therefore, there is a need for an open architecture modular test system. In particular, there is a need for a mechanism for managing pattern object files in a modular test system.

Method and structure to develop a test program for semiconductor integrated circuits


The illustrative embodiments described herein are directed toward an apparatus and method for coupling an embroidery accessory to an embroidery machine. The apparatus includes a support bar. The support bar is coupled to the embroidery machine. The apparatus also includes a set of acceptors. The set of acceptors are attached to the support bar. The apparatus also includes an embroidery accessory. The embroidery accessory includes a set of attachment adapters. The set of attachment adapters are adapted to be coupled to the set of acceptors.

1. Technical Field
The present invention is directed generally toward devices and methods for coupling an embroidery accessory to an embroidery machine.
2. Description of Related Art
Embroidery is generally used to create a decorative design or pattern on a piece of fabric. The fabric may be composed of any material, such as cotton, wool, polyester, plastic, silk, velvet, linen, or any other material capable of being stitched. A pattern may be embroidered onto the piece of fabric using an embroidery machine.
Embroidery machines lessen the amount of time and labor that is necessary to embroider an item by automating the embroidery process. For example, embroidery designs may be embedded in files that are loaded onto a computer. An embroidery machine may then communicate with the computer and embroider the designs that are contained on the files.
Embroidery machines require the use of an embroidery accessory in order to embroider a pattern onto fabric. The fabric is mounted onto the embroidery accessory so that the head of the embroidery machine may embroider the pattern on the fabric. Stabilizer or other types of backing may also be mounted on the embroidery accessory. Some embroidery accessories that are currently available for use with embroidery machines include cap devices, frames, or a set of arms.
However, attaching one of the currently available embroidery accessories to an embroidery machine can be cumbersome and time-consuming. For example, most current embroidery accessories must be bolted directly onto the pantograph of the embroidery machine. These types of embroidery accessories require an operator to bolt or unbolt embroidery accessories to and from the pantograph each time a new embroidery accessory is used, which can be cumbersome and time-consuming. This cumbersome and time-consuming method decreases the efficiency at which patterns may be embroidered onto pieces of fabric. Current methods for attaching and detaching embroidery accessories to and from an embroidery machine also require the use of one or more tools, such as a screwdriver or wrench. The need for additional tools presents an additional inconvenience of the current method for coupling and decoupling an embroidery accessory to and from an embroidery machine.

Apparatus and method for coupling an embroidery accessory to an embroidery machine


A liquid crystal display using horizontal electric field and a method of fabricating the liquid crystal display device that are capable of reducing the number of mask processes are provided. The liquid crystal display of horizontal electric field applying type has a thin film transistor array substrate, with a conductive film connected to a gate pad, a data pad and a common pad of a thin film transistor on the substrate. The pads are exposed on the thin film transistor array substrate.

1. Field of the Invention
The present invention relates to a liquid crystal display using a horizontal electric field, and more particularly to a liquid crystal display and a fabricating method thereof that are capable of reducing the number of mask processes.
2. Description of the Related Art
Generally, the liquid crystal displays (LCDs) control light transmittance of liquid crystal material using an electric field to thereby display a picture. The liquid crystal displays are classified into a vertical electric field type and a horizontal electric field type in accordance with a direction of the electric field driving the liquid crystal.
The liquid crystal display of vertical electric field type, in which a common electrode formed on an upper substrate and a pixel electrode formed on a lower substrate are arranged as facing each other, drives a liquid crystal of a twisted nematic mode (TN) by a vertical electric field formed between the common electrode and the pixel electrode. The liquid crystal display of vertical electric field type has an advantage of a large aperture ratio, while it has a defect of a narrow viewing angle of about 90°.
The liquid crystal display of a horizontal electric field type drives a liquid crystal in an in-plane switching (hereinafter referred to as "IPS") mode by a horizontal electric field between the pixel electrode and the common electrode disposed in parallel on the lower substrate. The liquid crystal display of horizontal electric field type has an advantage of a wide viewing angle about 160°. Hereinafter, the liquid crystal display of the horizontal electric field type will be described in detail.
The liquid crystal display of the horizontal electric field type comprises a thin film transistor array substrate(a lower substrate) and a color filter array substrate (an upper substrate) facing and joined to each other, a spacer for uniformly maintaining a cell gap between two substrates and a liquid crystal injected into a space provided by the spacer.
The thin film transistor array substrate includes a plurality of signal lines for forming a horizontal electric field on a basis of a pixel, a plurality of thin film transistors, an alignment film applied for a liquid crystal alignment thereon. The color filter array substrate includes a color filter for representing a color, a black matrix for preventing a light leakage and an alignment film applied for a liquid crystal alignment thereon.
In such a liquid crystal display, since the manufacture of a thin film transistor array substrate involves a semiconductor process and requires a plurality of mask processes, the complexity of the manufacturing process is a major factor raising the manufacturing cost of the liquid crystal display panel. In order to solve this, the thin film transistor array substrate has been developed to reduce the number of mask processes. This is because one mask process may include a lot of processes such as thin film deposition, cleaning, photolithography, etching, photo-resist stripping and inspection processes, to name a few. Recently, there has been highlighted a four-step mask process in which one mask process is reduced from the five-step mask process that is employed related art.
FIG. 1 is a plan view illustrating a related art thin film transistor substrate of a horizontal electric type using the four-step mask process, and FIG. 2 is a sectional view of the thin film transistor array substrate taken along the I-II′ and II-II′ line in FIG. 1.
Referring to FIGS. 1 and 2, the related art thin film transistor array substrate of the horizontal electric type comprises a gate line 2 and a data line 4 formed crossing each other on a lower substrate 45, a thin film transistor 6 formed at each crossing, a pixel electrode 14 and a common electrode 18 formed in order to apply the horizontal electric field in a pixel region defined by the interconnection part and a common line 16 connected to the common electrode 18. Further, the related art thin film transistor array substrate comprises a storage capacitor 20 formed at an overlapped portion between the pixel electrode 14 and the common line 16, a gate pad 24 connected to the gate line 2, and a data pad 30 connected to the data line 4 and a common pad 36 connected to the common line 16.
The gate line 2 supplies a gate signal to the gate electrode 8 of the thin film transistor 6. The data line 4 supplies a pixel signal to the pixel electrode 14 via a drain electrode 12 of the thin film transistor 6. The gate line 2 and the data line 4 are formed in an intersection structure to thereby define the pixel region 5.
The common line 16 is formed in parallel with the gate line 2 with the pixel region 5 positioned between the common line 16 and the gate line 2 to supply a reference voltage for driving the liquid crystal to the common electrode 18.
The thin film transistor 6 responds to the gate signal of the gate line 2 so that the pixel signal of the data line 4 is charged to the pixel electrode 14. To this end, the thin film transistor 6 comprises a gate electrode 8 connected to the gate line 2, a source electrode 10 connected to the data line 4 and a drain electrode 12 connected to the pixel electrode 14. Further, the thin film transistor 6 includes an active layer 48 overlapping with the gate electrode 8 with a gate insulating film 46 positioned between the thin film transistor 6 and the gate electrode 8 and defining a channel between the source electrode 10 and the drain electrode 12. The active layer 48 is formed to overlap with the data line 4, a data pad lower electrode 32 and a storage electrode 22. On the active layer 48, an ohmic contact layer 50 making an ohmic contact with the data line 4, the source electrode 10, the drain electrode 12, the data pad lower electrode 32 and the storage electrode 22 is further formed.
The pixel electrode 14, which is connected to the drain electrode 12 of the thin film transistor 6 via a first contact hole 13 passing through a passivation film 52, is formed in the pixel region 5. In particular, the pixel electrode 14 comprises a first horizontal part 14A connected to the drain electrode 12 and formed in parallel with adjacent gate line 2 and a second horizontal part 14B formed to overlap with the common line 16 and a finger part 14C formed in parallel with the common electrode 18.
The common electrode 18 is connected to the common line 16 and is formed in the pixel region 5. In addition, the common electrode 18 is formed in parallel with the finger part 14C of the pixel electrode 14 in the pixel region 5.
Accordingly, a horizontal electric field is formed between the pixel electrode 14 to which the pixel signal is supplied via the thin film transistor 6 and the common electrode 18 to which the reference voltage is supplied via the common line 16. Moreover, the horizontal electric field is formed between the finger part 14C of the pixel electrode 14 and the common electrode 18. The liquid crystal molecules arranged in the horizontal direction between the thin film transistor array substrate and the color filter array substrate by the horizontal electric field rotate due to a dielectric anisotropy. The light transmittance transmitting the pixel region 5 differs according to the amount of rotation of the liquid crystal molecules and thereby the pictures can be produced.
The storage capacitor 20 consists of the common line 16, a storage electrode 22 overlapping with the common line 16, with the gate insulating film 46, the active layer 48 and the ohmic contact layer 50 positioned therebetween, and a pixel electrode 14 connected via a second contact hole 21 passing through the storage electrode 22 and the passivation film 52. The storage capacitor 20 allows a pixel signal charged in the pixel electrode 14 to be stably maintained until the next pixel signal is charged.
The gate line 2 is connected, via the gate pad 24, to a gate driver (not shown). The gate pad 24 consists of a gate pad lower electrode 26 extending from the gate line 2, and a gate pad upper electrode 28 connected to the gate pad lower electrode 26 via a third contact hole 27 passing through the gate insulating film 46 and the passivation film 52.
The data line 4 is connected, via the data pad 30, to the data driver (not shown). The data pad 30 consists of a data pad lower electrode 32 extended from the data line 4, and a data pad upper electrode 34 connected, via a fourth contact hole 33 passing through the passivation film 52, to the data pad lower electrode 32.
The common line 16 is supplied with the reference voltage from the exterior reference voltage source (not shown) via the common pad 36. The common pad 36 consists of a common pad lower electrode 38 extended from the common line 16, and a common pad upper electrode 40 connected, via a fifth contact hole 39 passing through the gate insulating film 46 and the passivation film 52, to the common pad lower electrode 38.
A method of fabricating the thin film transistor substrate having the above-mentioned structure using the four-step mask process will be described in detail with reference to FIGS. 3A to 3D.
Referring to FIG. 3A, a first conductive pattern group including the gate line 2, the gate electrode 8 and the gate pad lower electrode 26 is formed on the lower substrate 45 using the first mask process.
More specifically, a first metal layer 42 and a second metal layer 44 are sequentially formed on the upper substrate 45 by a deposition technique such as sputtering to form a gate metal layer of double-structure. Then, the gate metal layer is patterned by the photolithography and the etching process using a first mask to thereby form the first conductive pattern group including the gate line 2, the gate electrode 8, the gate pad lower electrode 26, the common line 16, common electrode 18 and the common pad lower electrode 38. Herein, the first metal layer 42 is formed with an aluminum system metal and the second metal layer 44 is formed with chrome (Cr) or molybdenum (Mo).
Referring to FIG. 3B, the gate insulating film 46 is formed on the lower substrate 45 provided with the first conductive pattern group. Further, a semiconductor pattern group including the active layer 48 and the ohmic contact layer 50 and a second conductive pattern group including the data line 4, the source electrode 10, the drain electrode 12, the data pad lower electrode 32 and the storage electrode 22 are formed on the gate insulating film 46 using the second mask process.
More specifically, the gate insulating film 46, a first semiconductor layer, a second semiconductor layer and a data metal layer are sequentially formed on the lower substrate 45 provided with the first conductive pattern group by deposition techniques such as plasma enhanced chemical vapor deposition (PECVD) and the sputtering, etc. Herein, the gate insulating film 46 is made of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx). The first semiconductor layer is made of undoped amorphous silicon and the second conductor layer is made of amorphous silicon doped with an impurity of a N type or P type. The data metal layer is made of molybdenum (Mo), titanium (Ti), tantalum (Ta) or molybdenum alloy, etc.
A photo-resist pattern is formed on the data metal layer by the photolithography using a second mask. In this case, a diffractive exposure mask having a diffractive exposing part at a channel portion of the thin film transistor is used as a second mask, thereby allowing a photo-resist pattern of the channel portion to have a lower height than other photo-resist patterns of region portions.
Subsequently, the data metal layer is patterned by a wet etching process using the other photo-resist patterns to thereby provide the data pattern that included the data line 4, the source electrode 10, the drain electrode 12 being integral to the source electrode 10 and the storage electrode 22.
Next, the first semiconductor layer and the second semiconductor layer are patterned at the same time by a dry etching process using the same photo-resist pattern to thereby provide the ohmic contact layer 50 and the active layer 48.
The photo-resist pattern having a relatively low height is removed -from the channel portion by the ashing process and thereafter the source electrode, the drain electrode and the ohmic contact layer 50 of the channel portion are etched by the dry etching process. Thus, the active layer 48 of the channel portion is exposed to separate the source electrode 10 from the drain electrode 12.
A remainder of the photo-resist pattern on the second conductive pattern group is removed using the stripping process.
Referring to FIG. 3C, the passivation film 52 including first to fifth contact holes 13, 21, 27, 33 and 39 are formed on the gate insulating film 46 provided with the second conductive pattern group using the third mask process.
More specifically, the passivation film 52 is entirely formed on the gate insulating film 46 provided with the data pattern by a deposition technique such as the plasma enhanced chemical vapor deposition (PECVD). The passivation film 52 is patterned by the photolithography and the etching process using the third mask to thereby form first to fifth contact holes 13, 21, 27, 33 and 39. The first contact hole 13 is formed in such a manner as to pass through the passivation film 52 and expose the drain electrode 12, whereas the second contact hole 21 is formed in such a manner as to pass through the passivation film 52 and expose the storage electrode 22. The third contact hole 27 is formed in such a manner as to pass through the passivation film 52 and the gate insulating film 46 and expose the gate pad lower electrode 26. The fourth contact hole 33 is formed in such a manner as to pass through the passsivation film 52 and exposes the data pad lower electrode 32. The fifth contact hole 39 is formed in such a manner as to pass through the passivation film 52 and the gate insulating film 46 and expose the common pad lower electrode 38. Herein, when a metal which has high ratio of dry etching like molybdenum (Mo) is used for the data metal, the first contact hole 13, the second contact hole 21 and the forth contact hole 33 are formed in such a manner as to pass through to the drain electrode 12, the storage electrode 22 and the data pad lower electrode 32, respectively, to thereby expose their side.
The passivation film 52 is made of an inorganic insulating material such as the gate insulating film 46 or an organic insulating material having a small dielectric constant such as an acrylic organic compound, BCB (benzocyclobutene) or PFCB (perfluorocyclobutane), etc.
Referring to FIG. 3D, a third conductive pattern group including the pixel electrode 14, the gate pad upper electrode 28, the data pad upper electrode 34 and the common pad upper electrode 40 is formed on the passivation film 52 using the fourth mask process.
More specifically, a transparent conductive film is coated onto the passivation film 52 by a deposition technique such as sputtering, etc. Then, the transparent conductive film is patterned by the photolithography and the etching process using a fourth mask, to thereby provide the third conductive pattern group including the pixel electrode 14, the gate pad upper electrode 28, the data pad upper electrode 34 and the common pad upper electrode 40. The pixel electrode 14 is electrically connected, via the first contact hole 13, to the drain electrode 12 while being electrically connected, via the second contact hole 21, to the storage electrode 22. The gate pad upper electrode 28 is electrically connected, via the third contact hole 37, to the gate pad lower electrode 26. The data pad upper electrode 34 is electrically connected, via the fourth contact hole 33, to the data pad lower electrode 32. The common pad upper electrode 40 is electrically connected, via the fifth contact hole 39, to the common pad lower electrode 38.
In this connection, the transparent conductive film may be made of indium-tin-oxide (ITO), tin-oxide (TO), indium-zinc-oxide (IZO) or indium tin zinc oxide (ITZO).
As described above, the related art thin film transistor array substrate of the horizontal electric field type and the manufacturing method thereof adopts a four-round mask process, thereby reducing the number of manufacturing processes in comparison to the five-round mask process and hence reducing a manufacturing cost to that extent. However, since the four-round mask process still has a complex manufacturing process and limited cost reduction an approach is needed that is capable of further simplifying the manufacturing process and further reducing the manufacturing cost.

Liquid crystal display of horizontal electric field applying type and fabricating method thereof


A decomposable resin composition contains a base generator, and a polyurethane resin capable of being decomposed with a base generated from the base generator.

Decomposable resins and decomposable resin compositions means resins decomposable in response to an external factor, for example, a thermal factor, a mechanical factor, a photochemical factor, a radiation-chemical factor or a factor with a chemical agent and are well known. Change in the form (liquefaction or vaporization) or change in the nature or property, for example, molecular weight, hardness, viscoelasticity, glass transition point (Tg), solubility or adhesiveness of the resin or resin composition before and after the decomposition, which is caused by the decomposition of resin, is utilized in various fields.
Examples of the decomposable resin and decomposable resin composition include a biodegradable plastic (for example, polylactic acid) for decreasing environmental impact of plastic material and a slow releasing material which can gradually release a component, for example, medical agent or fragrance in the field of healthcare, cosmetic or life science. However, they gradually decompose by oxygen, light or enzyme in a natural environment, within the living body, in the soil or the like and thus they do not stably maintain their initial states and can not induce at once a large change in the nature upon the external stimulation.
Resins which are decomposed by light or heat for improvement in the recycling efficiency or simplification of the disposal and adhesives which decrease the adhesiveness thereof are also developed. Further, it is known that ceramic or carbon fiber is mixed with a decomposable resin and then the decomposable resin is removed, for example, by calcination to form a porous material. However, in these cases, the materials are altogether treated or processed and it is not intended to form the desired pattern only in the desired portion. Also, large energy is required for the decomposition treatment.
With respect to the application to image formation, for instance, it is known that both preservation stability and image fixability of toner are achieved by utilizing change in the nature due to heat at the heat-fixing of the toner containing a heat-decomposable resin. However, the resin per se does not have sufficient response to the pattern-wise stimulation.
As for pattern-forming materials, on the other hand, for example, a so-called chemically-amplified resist is well known as a photoresist. Specifically, a composition containing an acid generator and an acid-decomposable resin is pattern-wise exposed followed by heat treatment, if desired, to decompose pattern-wise the resin and the pattern is formed with development processing. Although the composition satisfies both the preservation stability and the pattern-forming property at a practical level, the development process in which the processing conditions are fully controlled is indispensable for the formation of pattern. Further, the pattern-formation in a thick layer having, for example, several tens of micrometers or more is difficult, though it is possible to apply to a thin layer.
A method of forming an image utilizing a step of removing (ablation) a part of thin layer by imagewise irradiation of laser beam is also known (JP-A-10-119436 (the term "JP-A" as used herein means an "unexamined published Japanese patent application")). However, the compounds recited as the heat-decomposable resin are only conventional general-purpose resins, for example, polyesters, polycarbonates or polyurethanes, and the thickness of the layer is only around 1 to 2 μm. It is also known to use a compound defined its heat decomposability (JP-A-10-244751 (corresponding to US 2002/0098439 A1)). However, the thickness of the layer described therein is also only around 1 to 2 μm.
As a mask material for paste printing to a printed circuit board or the like, a mask for forming a pattern having approximately 100 to 200 μm utilizing a photo-decomposable resin sheet and a production method of the mask are described (JP-A-8-258442). However, a specific compound does not disclosed in the patent. Also, the controlled development processing is indispensable in order to form the pattern while regulating the degree of exposure and development.
On the other hand, in order to form a pattern in a thick layer by a simple process, for example, pattern-formation by laser processing is known, in which the base material per se is removed, deformed or discolored by imagewise irradiation of laser beam. For instance, a method of recording information, for example, a lot number on a product (for example, video tape or home electric appliances) composed of a variety of base materials is utilized as a laser maker. In such cases, conventional resins are used as they are as the base material.
In the pattern-formation by laser processing, it is desired that a laser engraving portion (concave portion) be rapidly formed. For this purpose, a high-sensitive laser-decomposable pattern-forming material is needed.
In particular, in case of a flexographic printing plate precursor of a direct drawing type by laser (so-called flexographic printing plate precursor for laser engraving), since ease of engraving by laser beam (engraving sensitivity) dominates plate-making speed, a flexographic printing plate precursor for laser engraving using a high-sensitive laser-decomposable resin composition has been required.
On the other hand, as an example of composition containing a base generator, positive type photoresists containing a base generator are known (JP-A-2000-10270 and JP-A-2004-250650). In these examples, however, it is intended not to cause depolymerization of a polymer main chain but to cause change in responsiveness of the polymer to an aqueous alkaline solution or an aqueous acidic solution due to decomposition of side chain.
Further, as an example of laser-decomposable resin composition containing a compound which generates a base, a printing plate precursor capable of conducting laser engraving containing a developer generating a base and a color former is known (JP-A-2004-160898). However, the description of JP-A-2004-160898 does not suggest the combination of a polyurethane resin capable of being decomposed with a base and a base generator according to the invention. More specifically, JP-A-2004-160898 discloses the combination including a developer and a color former in order to form a dye having light absorption in a wavelength range of laser light after photo-curing and the combination does not satisfy the requirement of laser decomposability according to the invention. Further, when the decomposability of the resin is increased, a problem arises in that stability at the time of formation of thick layer decreases.

Decomposable resin composition and pattern-forming material including the same


An airbag apparatus includes an airbag module. The airbag module includes an inflatable cushion coupled to an inflator and a retainer. The airbag module additionally includes a cushion wrap. The cushion is folded such that it is in a storage position. The cushion wrap includes a slip section and a retainer end portion. The retainer end portion is affixed to the retainer and disposed adjacent to the slip section. The slip section includes a folded portion and frangible end portion. The folded portion is disposed between the frangible end portion and the retainer end portion. Furthermore, the frangible end portion is affixed to the retainer.

The present invention relates generally to the field of vehicle airbags. More specifically, the present invention relates to a vehicle airbag with a deployment feature. The deployment feature being a cushion wrap with a slip feature that provides a surface to serve as a guide for an airbag cushion to glide over an obstruction the airbag may encounter during deployment.
Vehicle airbags are used to protect vehicle occupants from injury in the event of a vehicle crash. Current airbag designs incorporate a variety of components that enhance the performance of the airbag: number and configuration of cushion folding techniques; tethers; venting positions; and tear seams included for the passive venting of the airbag.
In light of the above, there remains a continuing need in the art for improved airbag systems that are simple to install. There is also a need in the art for improved airbag systems that exhibit robust mechanical performance.

Protective cushion wrap with slip feature


An apparatus for processing an audio signal to focus an acoustic signal by an arrangement of a plurality of loudspeakers comprises a frequency analyzer, a signal processor and a signal output interface. The acoustic signal is based on the audio signal. The frequency analyzer is configured to determine a fundamental frequency in a frequency spectrum of the audio signal depending on a geometry parameter of the arrangement of the plurality of loudspeakers. The signal processor is configured to adapt an overtone of the fundamental frequency to obtain the processed audio signal and the signal output interface is configured to output the processed audio signal to the plurality of loudspeakers.

Embodiments according to the invention relate to an apparatus and a method for processing an audio signal to focus an acoustic signal by an arrangement of a plurality of loudspeakers, wherein the acoustic signal is based on the audio signal.
Some embodiments according to the invention relate to an improvement of sound focusing by using psychoacoustic effects.
In some applications, a directed emission of sound is desired. In this connection, the sound energy emitted by the sound source is to propagate in a preferred direction only. One possible application may be a sound system, that intends to provide a sound from the stage only to a certain audience area in the auditorium. The remaining auditorium should not be affected and/or unnecessary sound reflections on room walls are to be avoided this way. In terms of energy, the directed emission of sound may provide the possibility to emit the sound energy only in the direction in which it is needed.
The way in which sound is emitted from a sound source depends on the ratio of sizes between the sound-emitting surface and the considered wavelengths. In the case of wavelength (λ) being considerably larger than the membrane diameter, for example a canonical membrane, a non-directed sound emission takes place (see "Zollner, M.; Zwicker, E.: Elektroakustik, Springer-Verlag Berlin Heidelberg New York, 3. Auflage, 1. korrigierter Nachdruck 1998"). If the ratio is inverted, an increasing directed sound emission takes place with rising frequency and decreasing wavelength.
For loudspeaker arrays, the size of the array may, at least, correspond to half the wavelength of the lowest frequency in order to be able to emit sound in a directed way by the loudspeaker array, for example. Therefore, very large arrays are necessitated in particular for focusing down to low frequencies.
For example, there are two approaches for realization. The basis of the first approach is that the emitting area is made as large as possible with respect to the longest wavelength to be emitted. This approach is used, for example, in the Line-Array-Technology (see "Urban, M.; Heil, C.; Baumann, P.: Wavefront Sculpture Technology, presented at the 11th AES-Convention, 2001 Sep. 21-24, New York") used for large scale acoustic irradiation. By lining up acoustically-coupled single emitters, a large emitting membrane area is formed. In this approach, it is problematic that the dimensions of the sound source necessarily becomes unmanageably large.
If such large dimensions are not desired, a directed sound emission may be successful by decreasing the wavelength, instead of the size of the sound-emitting area, so that the ratio between the wavelength and the emitter size is met.
This approach is realized, for example, in ultrasonic loudspeakers (see EP 1 484 944 A2 or DE 699 21 558 T2). The problems of this approach consist in the non-proven harmlessness of the high ultrasonic doses for humans and in little low-frequency reproduction. Therefore, this approach is hardly used despite having been known for a longer period of time.
A possibility for extending the perceived low-frequency reproduction of sound sources is a use of a pyschoacoustic effect. It is known that the low frequency region perceived by humans may be enlarged by using pyschoacoustic effects. The reproduction bandwidth perceived by humans is not necessarily equal with the physically reproduced bandwidth of a sound source. By using pyschoacoustic effects, the reproduced signal may be changed such that a listener gets the impression that, for example, the perceived low-end cut off frequency is lower than the physically existing one.
This is done by processing the useful signal in such a way that the harmonic overtones of the fundamental waves are formed such that an enhanced low frequency impression develops. In this connection, the actual fundamental frequency only needs to be reproduced very weak or even not at all. An often-used pyschoacoustic effect is, for example, the missing fundamental effect. Here, the harmonic overtone structure of the signal is influenced such that despite of non-reproduced fundamental frequencies, the human believes to perceive these (see U.S. Pat. No. 6,134,330 or "Larsen, E.; Aarts, R. M.: Audio Bandwidth Extension, John Wiley & Sons, Ltd., West Sussex, England, 2004").
Some further examples for the psychoacoustic effect are shown in "Be-Tzur, D. et al.: The Effect of MaxxBass Pyschoacoustic Bass Enhancement on Loudspeaker Design, 106th AES Convention, Munich, Germany, 1999", in "Woon S. Gan, Sen. M. Kuo, Chee W. Toh: Virtual bass for home entertainment, multimedia pc, game station and portable audio systems, IEEE Transactions on Consumer Electronics, Vol. 47, No. 4, November 2001, page 787-794", at "http://www.srslabs.com/partners/aetech/trubass_theory.asp", at "http://vst-plugins.homemusician.net/instruments/virtual_bass_vb1.html", at "http://mp3.deepsound.net/plugins_dynamique.php", and at "http://www.srs-store.com/store-plugins/mall/pdf/WOW%20XT%Plug-inmanual.pdf".
Further examples for sound focusing are shown in "DEGA-Empfehlungen 101, Deutsche Gesellschaft für Akustik e.V., März 2006", in "Yoomi Hur, Seong-woo Kim, Young-cheol Park, Dae Hee Youn: Highly focused sound beamforming algorithm using loudspeaker array system, presented at the 125th AES-Convention, 2008 Oct. 2-5, San Francisco", and in "Jung-Woo Choi, Youngtae Kim, Sangchul Ko, Jungho Kim: Super-directly loudspeaker array for the generation of personal sound zone, presented at the 125th AES-Convention, 2008 Oct. 2-5, San Francisco".

Apparatus using missing fundamental frequencies to improve loudspeaker sound focusing

Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.


A method for obtaining a high resolution digital image from a plurality of starting images formed by pixel matrices and acquired at a lower resolution is provided. The method may include combining the plurality of starting images to generate a provisional high resolution image formed by a pixel matrix. The method may also include associating a respective error with at least a part of the pixels of the provisional image HR(0). More particularly, this may include providing a first error associated with at least one first pixel, and at least partially processing the provisional image by modifying the pixels of this image based upon the respective errors associated therewith. A second error may also be calculated to associate with at least one second pixel situated in the vicinity of the first pixel in the matrix (HR(0)). The second error may be calculated by using the first error associated with the at least one first pixel.

Digital images are currently used in many different applications. For example, new-generation acquisition devices, such as digital still cameras (DSCs), are commonly used for capturing such images. The availability of sensors of ever greater resolution and low-cost, low-consumption digital signal processors (DSPs) has led to considerable commercial availability of digital still cameras. Yet, it may still be relatively expensive to produce devices that are capable of capturing high-quality digital images.
The quality of an image depends substantially on the characteristics of the sensor with which the image is acquired. This is particularly true for image resolution. The sensor, which in digital still cameras is typically either a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor, is an integrated circuit including a matrix of photosensitive cells or elements, each associated with a corresponding pixel. When the image is acquired from a real scene, each cell produces an electric signal proportional to the light that strikes it. More particularly, each cell responds to the radiance (i.e., emitted quantity of light) of a particular portion of the real scene. This portion is the receptive field of the pixel.
The larger the number of photosensitive cells or the greater the spatial resolution of the sensor (which provide the same result), the denser the information relating to the real scene captured in the acquisition process will be. But the choice of obtaining a higher image resolution by increasing the sensor resolution in terms of number of pixels is not always feasible for reasons that are both technological and economic in nature.
Moreover, when acquiring a digital photograph a sensor, no matter how good its resolution, will always produce an approximation of the scene that is to be captured. Further, the photosensitive cells of the sensor are always separated by a certain distance. This is because not all the sensor area can be uniformly covered with photosensitive elements, and technological reasons make it inevitable that there will be a certain minimum distance between adjacent cells. This spacing is the cause of a first loss of information in the acquisition process.
Another reason why a digital image acquired with a digital still camera sensor provides only an approximation of the real scene is a result of the interpolation process for processing the data acquired by the sensor. As is well known, a digital image may be represented by a matrix of elements (i.e., pixels) corresponding to elementary portions of the image. Each of these elements has associated with it one or more digital values representing the optical components. In a monochromatic image, for example, only a single digital value is associated with each pixel. In this case, the image is made up of only a single channel or plane.
On the other hand, in a color image (which may be in red green blue (RGB) format, for example) each pixel has associated therewith three digital values that correspond, respectively, to the three components (red, green, blue) of the additive chromatic synthesis. In this case the image can be broken down into three distinct planes, each including the information relating to just one of the chromatic components.
A typical sensor will dedicate a single and substantially monochromatic photosensitive cell to each pixel of the image. Furthermore, the sensor is provided with an optical filter including a matrix of filtering elements, each of which covers one photosensitive cell. Subject to a minimal absorption, each filtering element transmits to the photosensitive cell with which it is associated the luminous radiation corresponding solely to the wavelength of the red light, green light, or blue light. Thus, for each pixel only one of the three primary components (R,G,B) of the additive chromatic synthesis is avilable.
The type of filter used varies from one manufacturer to the next. Perhaps the most common of these filter is the Bayer filter. With this filter, the arrangement of the filtering elements is in the "Bayer" pattern, which is shown in the element matrix 10 illustrated in FIG. 2. The electric signals produced by the photosensitive cells are converted into digital values in accordance with conventional methodologies. The digital image obtained in this manner is incomplete. This is because the image is made up of only a single component (R, G or B) for each pixel. The format of this image is conventionally referred to as a color filter array (CFA).
The CFA image is then subjected to a complex reconstruction process to produce a "complete" image (e.g., in RGB format) in which three digital values will be associated with each pixel. This reconstruction implies a passage from a representation of the image in a single plane (Bayer plane) to a representation in three planes (R,G,B). The reconstruction is accomplished through known interpolation algorithms.
It should be noted that the interpolation produces only an approximation of the image that would be obtained with a sensor capable of acquiring three optical components per pixel. In this sense, therefore, the interpolation process introduces yet another approximation into the acquired image.
Given these limitations of the quality of the acquired image introduced by the sensor characteristics and the interpolation process, it is often necessary to perform further processing operations to obtain a high resolution digital image. To this end prior art proposes numerous processing methods. These are generally based on the principle of reconstructing the original information of the real scene by combining the information in a plurality of initially acquired low resolution digital images that all represent the same scene.
To this end, it is necessary that the initially acquired images (which will be reffered to as the "starting images" herein) should together provide some additional information that could not be obtained from identical images. Certain of the prior art methods operate in the spatial domain (i.e., in the pixel domain), and others in the frequency domain. The latter combine a certain number of low resolution starting images after having transformed them in the spatial frequency domain. After the image in the frequency domain obtained from this combination has been brought back into the spatial domain, it has a better resolution than the starting images. However, the methods operating in the frequency domain call for a very considerable computational effort.
The methods that operate in the spatial domain, on the other hand, use an approach known as "back projection", which is similar to the one utilized, for example, in computer-aided axial tomography (CAT). According to this approach, a two-dimensional object is reconstructed from a series of one-dimensional projections thereof.
The back-projection approach assumes that the low resolution starting images of a real scene represent different projections of a high resolution image that reproduces the real scene. The projection operation is by the same acquisition process, which depends to a large extent on the acquisition device, and is assumed to be known. The problem is thus reduced to reconstructing the high resolution image from its various projections.
In particular, the method used by M. Irani and S. Peleg, described in an article entitled "Super Resolution From Image Sequences" (IEEE, 1990), obtains an iterative reconstruction of the high resolution image by correcting/improving this image in several successive steps. This is done based upon differences between the starting images and images obtained by simulation from the projections of the high resolution image as corrected or improved from time to time (by iteration).
This method has a first drawback in that obtaining high-quality images requires an accurate modelling of the acquisition process (or device) with which the low resolution images have been obtained. For this reason, the above-described approach results in a complicated method that does not lend itself to being implemented in a commercial acquisition device such as a digital still camera.
A second difficulty is that this method requires a considerable number of iterations at each iteration step. This, in turn, may be problematic in devices in which power, processing and data storage resources are at a premium and may effect the commercial success of a product.

Processing method for obtaining a high resolution digital image


A thin-film magnetic head that shows stable read and/or write performances, maintaining the reliability over time by suppressing the wear of the head sufficiently, is provided. The head comprises: a substrate having an element-formed surface and an opposed-to-medium surface; a magnetic head element; an overcoat layer formed on the element-formed surface so as to cover the magnetic head element; a closure provided on the overcoat layer, a surface of the closure being in contact with the upper surface of the overcoat layer; and an element contact pad formed in a sliding-side surface of the head and having a contact surface including a part of the opposed-to-medium surface, a part of an end surface of the overcoat layer and a part of an end surface of the closure, one end of the magnetic head element reaching the contact surface.

1. Field of the Invention
The present invention relates to a thin-film magnetic head that comprises a closure and makes contact with a magnetic recording medium, a head gimbal assembly (HGA) with the thin-film magnetic head and a magnetic recording apparatus with the HGA and the medium.
2. Description of the Related Art
A magnetic disk drive apparatus such as a hard disk drive (HDD) or a flexible disk drive (FDD) is a representative example of the magnetic recording apparatuses, which is portable and lower in price per byte than semiconductor memory. Recently, because the volume of various data becomes larger due to the spread use of the multimedia and the Internet, the magnetic disk drive apparatus is strongly required to have much larger capacity and to be further miniaturized.
In the situation, a contact-type apparatus is worth noting because of its possibility of higher recording density, which, for example, has a loading mechanism for transferring an inserted cartridge including a disk to the predetermined position, a rotary drive mechanism for holding and rotating the disk in the transferred cartridge, a magnetic head device for writing data signals to the rotated disk and reading data signals from it, and a moving mechanism for moving the magnetic head device in the radial direction on the disk.
The magnetic head in the magnetic head device writes and reads data signals in contact with the magnetic disk. A Metal-In-Gap (MIG) head has conventionally used as the contact-type head. However, in order to respond the increasing data storage capacity and the further miniaturization of the magnetic disk drive apparatus, a thin-film magnetic head for an HDD, which inherently meets higher recording density, is being applied to the contact-type apparatus. The thin-film magnetic head for the HDD has a structure suitable for flying on the magnetic disk without contact during read and write operations. Therefore, the simple use of the thin-film magnetic head under the contact condition may cause a significant wear or crash of the head. To avoid the problem, U.S. Pat. No. 6,947,259 proposes the limitation to a predetermined range of the distance between an electromagnetic transducer (magnetic head element) and the contact edge of an overcoat layer. Further, Japanese Patent Publication No. 06-309625A describes a contact-type head for perpendicular magnetic recording with the sliding surface of an antiwear layer.
Furthermore, U.S. Pat. No. 5,142,768 and Japanese Patent Publications Nos. 08-321012A and 06-012622A describe a magnetic head used for a magnetic tape drive etc., which has a bonded protection plate such as a closure block.
However, in the head described in U.S. Pat. No. 6,947,259, the sliding surface of the protective film is still worn largely, and especially when an alumina thick film is used as the protective film, the degree of wear becomes larger than that of the slider substrate. Further, the formation of the thick film with thickness of 50 to 200 micrometers requires significant man-hours. A contact-type head described in Japanese Patent Publication No. 06-309625A has the same kind of problem.
Further, when the "closure-type" magnetic head described in U.S. Pat. No. 5,142,768 and Japanese Patent Publications Nos. 08-321012A and 06-012622A is used for a magnetic disk drive apparatus such as a FDD, the contact edge of the whole magnetic head is rather separated from the contact end of the head element during read and write operations. Therefore, the area of the magnetic disk such as the flexible disk opposed to the end of the head element is bent, then the bending is likely to cause the distance between the end of the head element and the disk surface to be fluctuated. As a result, read and write performances may become unstable.

Thin-film magnetic head comprising contact pad including portions of closure and substrate and magnetic recording apparatus comprising the head


The present invention provides a foamable composition for administration to the skin, body surface, body cavity or mucosal surface, e.g., the mucosa of the nose, mouth, eye, ear, respiratory system, vagina or rectum, and methods of using such a composition to treat, alleviate, or prevent a disorder of the skin, body cavity, or mucosal surface. The foamable oil in water nano emulsion composition includes: (a) a nano oil globule system, comprising substantially of sub-micron oil globules; (b) about 0.1% to about 5% by weight of at least one stabilizing agent selected from (i) a non-ionic surfactant, (ii) an ionic surfactant, or (iii) a polymeric agent; and (c) a liquefied or compressed gas propellant at a concentration of about 3% to about 25% by weight of the total composition, water and optional ingredients. Upon release from an aerosol container, the foamable composition forms and expanded foam suitable for topical administration.

Foams and, in particular, foam emulsions are complex dispersion systems which do not form under all circumstances. Slight shifts in foam emulsion composition, such as by the addition of active ingredients, may destabilize the foam.
Micro emulsions and nano emulsion can be monophasic, transparent (or slightly translucent) dispersions of oil and water. Unlike conventional emulsions, micro emulsions and nano emulsion can be thermodynamically stable, making them a favorable vehicle for pharmaceutical compositions, which have to maintain stability for long periods of time. Micro emulsions are sometimes said to be misleadingly called micro emulsions since they can form clear solutions devoid of the opaque color of regular emulsions. Micro emulsions can be oil external, water external and middle phase. Nano emulsions in contrast can be very fine oil in water dispersions. Droplet diameters can be as low as smaller than 100 nm. They can be in a metastable state and their structure can depend on the system history. They can be very fragile systems and can therefore be problematic in trying to formulate pharmaceutical and cosmetic compositions. If destabilized they can become opaque or exhibit creaming. On the other hand they can provide useful applications in skin care in that they may exhibit good textural and sensural properties due to the very fine droplet or globule size. Likewise for similar reasons they may provide more rapid penetration than conventional emulsions and can offer hydrating capabilities.
Foams are very complex and sensitive systems and are not formed at will. Mere addition of basic ingredients like oil, water, surfactant and propellant is far from sufficient to produce foams of quality that are homogenous, stable, breakable upon mechanical force and can be used to provide a shelf stable pharmaceutical or cosmetic composition. Small deviations may lead to foam collapse. Much consideration needs to be given to facilitate the introduction of an active agent, such as examining compatibility and non reactivity with the various excipients and container and determining shelf life chemical stability. All these considerations become a greater and more non obvious challenge when trying to formulate a foamable nano-emulsion composition, which demands the symbiosis and compatibility of a complex, sensitive system with a fragile and metastable system to produce a homogenous, stable, breakable shelf stable nano foam. Moreover, nano droplets can be sterilized by filtration.
Storage triacylglycerols (TAG) in plant seeds are present in small discrete intracellular organelles ranging from 1 to 2 μm, which are called oil-bodies. An oil body has a matrix of TAG, which is surrounded by phospholipids (PL) and alkaline proteins, termed oleosins. Oleosins are highly lipophilic proteins, are expressed at high levels in many seeds and are specifically targeted to oil-bodies. Oil-bodies are abundant in plant seeds and are among the simplest organelles present in eukaryotes. They are remarkably stable both inside the cells and in isolated preparations.
Oil bodies are also termed in the literature as "oleosomes", "lipid bodies" and "spherosomes".

Foam prepared from nanoemulsions and uses


An apparatus and method for a time division multiple access (TDMA) network backbone comprising a plurality of nodes interconnected by links. Each node has receive antennas and transmit antennas for communicating radio frequency (RF) bursts, and a node control for communicating node information. The receive antennas are operated in accordance with TDMA receiving slots and the transmit antennas are operated in accordance with TDMA transmit slots. A timing reference subsystem provides timing signals for the nodes for efficiently utilizing the transmission links formed between given nodes.

The effectiveness of a communication network depends essentially on its network architecture, components and operating conditions. Antennas are critical components in a mobile communication network. A properly chosen antenna can significantly enhance the performance of a mobile communication network.
A phased array antenna (PAA) employs spatially narrow radio frequency (RF) beams to communicate between the network nodes. Electronic beam steering allows the PAA beams to be retargeted instantly after a gap of minimum set-up time for loading the PAA shift registers. In a synchronous link approach the transmit beam of a first PAA is pointed towards the receive beam of a second PAA. Similarly, the transmit beam of the second PAA is pointed towards the receive beam of the first PAA. In the synchronous approach, each node having PAAs can form no more links than the number of beams on its PAAs. Consequently, the network's performance is limited by the number of beams on the PAAs.
Simulations of typical PAA based networks show that for a given spatial distribution of the nodes, the number of links actually available is much smaller than the maximum number of available links. This results in the average packet route going through several node hops, which is very inefficient. Adding more PAAs imposes increased demands of weight, power and physical space. Increasing the number of beams per PAA results in higher cost and thermal load per unit. Therefore, there is a need to implement a PAA based efficient network design.
Synchronous links can be used to implement a backbone of a network. In such an approach, the nodes on the backbone communicate among themselves using long-duration synchronous links. In real world networks, e.g., military networks, a single network backbone is connected to a number of terminal nodes. The backbone to terminal links use short bursts of RF energy in a time division multiple access (TDMA) approach. This requires the backbone nodes to have two sets of PAAs, one set to cover 4π steradian sky for maintaining continuous links to other backbone nodes, and another set to cover 4π steradian sky for TDMA links connecting to the terminal nodes. Two full sets of antennas make additional demands in terms of space, power and weight to accommodate the extra set of antennas. For military aircraft, such demands are prohibitive. Further, the mounting of extra antennas requires additional aircraft fuselage penetrations. Thus, there is a need for a network with a single set of PAAs to communicate with both the backbone and terminal nodes in the network.
In a synchronous link based backbone network, a group of terminal nodes communicating with the TDMA links cannot function as an independent network, i.e., a peer-to-peer network, without connecting to some backbone node. In military environments, a backbone node may not be accessible in some critical circumstances, making the network unavailable. Hence, there is a need for a PAA based network which will allow formation of a network made exclusively of terminal nodes.


An electronic ballast is provided with a filament heating circuit having a Q factor clamped at a certain range of preheat frequency. An inverter circuit includes a pair of switches coupled between positive and negative terminals of a power supply, which oscillate at an operating frequency and generate an output voltage. A main resonant tank is coupled between an inverter output and the negative power supply terminal. A filament heating resonant tank includes a primary winding of a filament heating transformer coupled on a first end in series with the resonant capacitor, first and second capacitors coupled in series between the second end of the primary winding and the negative power supply terminal. A clamping circuit coupled to the second capacitor during a preheat mode of operation clamps an amplitude of the voltage across the primary winding to an amplitude of the input voltage from the power supply.

The present invention relates generally to program start electronic ballasts for powering discharge lamps with filament heating. More particularly, the present invention relates to program start ballasts having a resonant filament heating circuit configured with circuitry to clamp the quality ("Q") factor of the oscillator.
Program start ballasts are known to be very useful for conditions where lights are expected to be frequently turned on and off, as they can properly operate the lamp filaments to generally extend the lamp life. To obtain a longer lamp life a program start ballast has to properly heat the lamp filaments before ignition of the lamp, but after ignition has been achieved further filament heating is unnecessary as long as the lamp current is sufficiently high.
Therefore a filament heating circuit for a program start ballast would desirably have strong filament heating capability, with a constant filament heating output voltage that is substantially insensitive to component variation and to preheat frequency.
It would be further desirable to automatically scale back or disable the filament voltage after ignition of the lamp to improve the efficiency of the total ballast.
It would be even further desirable that the ballast circuitry always operated in an inductive mode rather than capacitive mode to ensure soft switching during the preheat period of the half-bridge inverter that powers the filament heating circuit. In other words, the preheat frequency should be greater than a resonant frequency for the filament heating circuit.
In any case, it would be desirable to provide a filament heating circuit that is relatively simple and of low cost.
Referring to FIG. 1, a ballast 10 for powering one or more lamps 18 may be provided with a voltage driven, series resonant inverter circuit as shown that is known to those of skill in the art as an option to provide these functions. The ballast 10 may include a pair of inverter switches Q1, Q2 driven at a certain frequency (f) by a controller or drive circuit 12 which may generally be an integrated circuit 12. The switches Q1, Q2 convert an input signal from the DC voltage source Vdc into a square wave AC output. The primary winding Tp of filament heating transformer T1 and capacitor C1 in the configuration shown form a resonant tank 14. Secondary windings Ts1, Ts2 are coupled to output terminals 16 for the ballast and used to drive lamp filaments for one or more lamps that may be coupled to the output terminals 16.
Referring now to FIG. 2, an output voltage characteristic of the ballast circuit 10 of FIG. 1 is shown with respect to the switching frequency (f) of the inverter switches Q1, Q2. The output voltage Vout is the voltage across the primary winding Tp of the filament heating transformer T1. The natural resonant frequency associated with the components Tp, C1 of the resonant tank 14 is fres. When the switching frequency (f) approaches or otherwise operates nearby the resonant frequency (fres), such as in this example at the preheat frequency (fpre), the output voltage Vout is large and output power capability is correspondingly large as well. When the switching frequency (f) operates far away from the resonant frequency (fres), such as in this example at the steady-state frequency (fsteady), the output voltage Vout will be quite small. Therefore a filament heating circuit 10 as shown is low cost, has strong preheating capability where the switching frequency (f) is near the resonant frequency (fres), and further can naturally scale back the output voltage Vout in steady state operation where the switching frequency (f) is reduced to (fsteady).
However, this circuit 10 has significant drawbacks as well. The output voltage Vout is undesirably sensitive to variations in the preheat frequency (fpre) and other component variation, as operation of the circuit at the preheat frequency (fpre) is also quite close to the natural resonant frequency (fres) for the circuit 10. Another way of describing this problem is to observe that the quality factor (Q factor) for this circuit 10 and resonant tank 14 is quite large and that small variations in frequency near the resonant frequency result in large variations in the output voltage.
Further, the operating mode of the circuit is capacitive because the preheat frequency (fpre) is less than the natural resonant frequency (fres), and therefore soft switching is not ensured.

Self-clamped resonant filament heating circuit


A method and system for regulating the operation of a cardiac pacemaker or defibrillator are disclosed. A processor receives signals of both an implanted hemodynamic sensor and intracardiac electrograms and digitizes them. The digitized signal of the hemodynamic sensor is used to prevent inappropriate cardiac stimulation and erroneous cardiac detection. The hemodynamic signal is also used to define arrhythmias.

There are two copending patent application from the author of the present invention contents of which are hereby incorporated herein by reference; first Copending PCT Patent Application Serial Number PCT/IL2004/000659, filed Jul. 20, 2004 entitled, "ADAPTIVE RESYNCHRONIZATION THERAPY SYSTEM", published Apr. 14, 2005, under publication number WO 2005/007075; second Copending PCT Patent Application Serial Number PCT/IL2006/000571, filed May 15, 2006 entitled, "VENTRICLE PACING DURING ATRIAL FIBRILLATION EPISODES".
Implanted cardiac stimulation devices, i.e. pacemakers and intracardiac cardioverter defibrillators (ICD) deliver therapy to patients suffering from various heart-diseases (Clinical Cardiac Pacing and Defibrillation, 2nd edition, Ellenbogen, Kay, Wilkoff, 2000). Dual chamber pacemakers stimulate the right ventricle with synchrony to the sensed atrial event, with a given delay, the atrioventricular (AV) delay. Cardiac Resynchronization Therapy (CRT) devices, e.g., biventricular pacemakers, stimulate both ventricles and also synchronize the stimulation in correspondence with the sensed atrial event signal. With all implanted cardiac stimulation devices the management of the stimulation according to the accurate sensing and interpreting the electrical activity of the heart in the atria and in the ventricles is crucial for the variety of stimulation methods and algorithms. U.S. Pat. No. 6,901,291 disclose a method to distinguish between valid and invalid cardiac senses. U.S. Pat. No. 6,862,471 discloses a method for blanking T-waves from atrial cardiac signals. U.S. Pat. No. 6,912,418 discloses a system for distinguishing electrical events originating in the atria from far-field electrical events originating in the ventricles. U.S. Pat. No. 6,731,978 discloses a prioritized rule based method for detection, classification and treatment of arrhythmias.
Generally, these methods are related to the timing cycles in cardiac stimulation. The timing cycles are very important for proper operation of the implanted stimulation device and to the safety and well being of the patient. Under conditions of cardiac arrhythmias, these timing cycles become even more important and complicated to manage. In the prior art the only information used on-line are the electrical signals sensed by the implanted electrodes, i.e. the intra cardiac electrograms (IEGMs). The difficulty associated with depending solely on the IEGMs stems from the fact that the sensed signals are local and weak, having an amplitude of only several milli-volts with strong coupling from ventricle to atria and ventricle to ventricle. Hence the IEGMs can be misinterpreted by the device controller which can lead to inappropriate pacing.
Implanted cardiac hemodynamic sensors are known in the art and are further developed by several manufactures, mainly for minimal invasive electrophysiological studies. In the last years few cardiac pacemaker devices included such hemodynamic sensors for hemodynamic monitoring and for creating a pacemaker system with a rate response according to hemodynamic sensors.
U.S. Pat. No. 6,865,419 proposes to use an implanted pressure sensor in order to measure the mean pulmonary arterial pressure. U.S. Pat. No. 6,882,882 proposes to use an implanted pressure sensor in order to adjust the atrioventricular delay online.
Prior art US Patent 2003/0158492 A1 presents a method for detection and treatment of myocardial ischemia based on monitoring of both the electrical and the mechanical activity of the heart in order to detect and verify more reliably the myocardial ischemia occurrence. When myocardial ischemia is detected and verified the patent suggests selecting between few options of therapy.
Prior art U.S. Pat. No. 5,458,622 A presents a method for detection, classification and treatment of pathological tachyarrhythmia from physiologic tachyarrhythmia based on implanted activity sensor.
Prior art European Patent 0488512 A2 presents an implantable hemodynamically responsive cardioverting/defibrillating pacemaker. The implantable device uses the information of the implanted hemodynamic sensor during tachycardia to select and control therapeutic means delivered such as antitachycardia pacing (ATP), cardioversion or defibrillation options.
Prior art US Patent 2002/0103442 A1 presents a system and a method for determining mean pulmonary arterial pressure (MPAP) using a pressure sensor located within a ventricle of a heart. The MPAP approximates the mean pressure of the pulmonary artery that can be used to optimize CRT device timings for example.
Prior art European Patent 0541338 A1 presents an implantable monitor/stimulator that monitors and assesses indices of cardiac function and automatically executes physician-selected mode of therapy with ability to increase the strength of contractility of the heart.
The prior art patents cited above use a hemodynamic sensor as a mean to detect specific heart condition (US Patent 2003/0158492), detect and treat cardiac arrhythmias (EU0488512 A2 and U.S. Pat. No. 5,458,622 A) or improve hemodynamic function (US2002/0103442 and EU0541338). The prior art patents cited above do not suggest to use the implanted hemodynamic sensor in order to prevent inappropriate cardiac stimulation or to detect erroneous cardiac events interpretation.
In the present invention a general approach and specific examples are presented that combines information from hemodynamic sensor with the information from the intracardiac electrograms for making a more reliable and safer cardiac stimulation operation. Our approach takes advantage of the fact that implanted hemodynamic sensors are being developed and implemented in implanted cardiac pacemakers and defibrillators in order to improve hemodynamic performance and to be used for future closed loop implanted devices and since such sensors become available, the present invention suggest to further use the complementary data from the hemodynamic sensor as explained in details below.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Cardiac stimulation with hemodynamic sensor guard


A detachable battery pack is connectable to hand-held power tools, such as spiral cutting tools, in which cuts are made by positioning the axis of the cutting tool motor housing perpendicular to a workpiece surface, and moving a cutting tool bit through the workpiece in a direction perpendicular to the axis of the bit to remove material from the workpiece. The battery pack allows the cutting tool to be utilized without an electric cord and without the need of a power source near-by, thereby increasing maneuverability, safety, and range of use. The battery pack is connected to the motor housing of the power tool by being received by a receptacle. The receptacle is preferably formed to include one or more storage compartments therein, accessible through apertures in the receptacle for storage of additional cutting tool bits. A sliding door on the receptacle may be provided to allow access to the storage compartments, and to close the compartments to secure items stored therein during operation of the cutting tool. The receptacle extends outwardly beyond the motor housing over a handle so that the weight of the battery pack is centered over the handle.

A spiral cutting tool is a hand-held power tool having an electric motor that rotates a spiral cutting tool bit at high speeds. Such tools are particularly useful for cutting sheets of material such as drywall and plywood. The spiral cutting tool bit includes a sharp cutting edge that is wrapped in a spiral around the axis of the bit. The spiral cutting tool bit is designed for cutting perpendicularly to the axis of the bit. The electric motor that drives the bit is enclosed in a motor housing. The motor housing is generally cylindrical in shape, with the spiral cutting tool bit extending from one and of the motor housing along the axis of the housing. The spiral cutting tool is used to remove material from a workpiece by moving the rotating spiral cutting tool bit through the workpiece in a direction perpendicular to the axis of rotation of the bit. It is conventionally operated by grasping the motor housing with one or both hands, turning on the electric motor to begin high speed rotation of the spiral cutting tool bit, spinning the cutting bit into a work piece, such as a piece of wood, and then moving the cutting bit through the workpiece in a direction perpendicular to the axis of the spiral cutting tool bit by moving the motor housing in a direction parallel to the plane of the workpiece surface while keeping the axis of the motor housing generally perpendicular to the workpiece surface.
The spiral cutting tool is typically powered by means of an electric cord attached to a power source. However, use of a cord has several drawbacks. First, the cord may limit the cutting motions of the operator by being in the way. Second, it presents a possible safety hazard, as a cord over which the operator may trip or which may entangle with other objects during use. Third, it limits the range of operation of the tool; when a power source is not nearby, the operator must use an extension cord, or not use the tool at all. In addition, the operator may waste time in travelling to and from the power source to plug and unplug the cord.
Spiral cutting tool bits are available in various sizes and configurations specifically designed for the cutting of different workpiece materials. A spiral cutting tool operator will likely desire to have extra bits conveniently at hand. Spiral cutting tool bits are changed by removing bits from and inserting bits into a chuck connected to the spiral cutting tool motor. This process typically requires use of a wrench or other tool. Extra spiral cutting tool bits and other spiral cutting tool accessories may be brought to a work site in a toolbox or other conventional storage container, wherein they will likely become mixed up with other tools, and accessories for other power tools, such as conventional drill bits. This can result in wasted time as the spiral cutting tool operator searches through his tool box for the desired spiral cutting tool bit, wrench, etc. In addition, the tool box may not be convenient to the work space in which the operator is using the spiral cutting tool, resulting in additional wasted time in walking to and from the tool box to retrieve the accessories. It generally is not convenient to bring a separate container to the work site for the specific purpose of holding spiral cutting tool bits and accessories alone.

Spiral cutting tool with detachable battery pack


The present invention relates to an oral pharmaceutical composition of aliphatic amine polymer or salts thereof comprising mixture of water and organic solvent(s) and/or less than of about 10% of plasticizing agent in the coating composition. In particular, present invention relates to a coated pharmaceutical composition of aliphatic amine polymer or salt thereof which comprises mixture of water and organic solvent(s) and less than of about 10% of plasticizing agent in coating. The invention also includes process of preparing such composition.

The aliphatic amine polymer is a cross-linked polyallylamine with a pharmaceutically acceptable acid. The aliphatic amine polymer is an epichlorohydrin-cross-linked polyallylamine with a pharmaceutically acceptable acid, such as sevelamer, sevelamer hydrochloride, colesevelam or its hydrochloride salt.
The colesevelam hydrochloride is a non-absorbable, polymeric and a high-capacity bile acid-binding molecule. It is also a lipid-lowering and glucose-lowering agent intended for oral administration. Colesevelam hydrochloride is poly (allylamine hydrochloride) cross-linked with epichlorohydrin and alkylated with 1-bromodecane and (6-bromohexyl)-trimethylammonium bromide. Colesevelam hydrochloride is hydrophilic and insoluble in water. Chemically, allylamine polymer with 1-chloro-2,3-epoxypropane, [6-(allylamino)-hexyl]trimethylammonium chloride and N-allyldecylamine, hydrochloride and is represented by the following formula:

In the structure, m represents a number ≧100 to indicate an extended polymer network.
Colesevelam hydrochloride is approved in United States under the proprietary name Welchol® as oral tablet and marketed by Daiichi Sankyo.
Welchol® is indicated as an adjunct to diet and exercise to reduce elevated low-density lipoprotein cholesterol (LDL-C) in adults with primary hyperlipidemia (Fredrickson Type IIa) as monotherapy or in combination with HMG CoA) reductase inhibitor (statin) and as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.
U.S. Pat. No. 7,229,613 discloses a method for treating hyperglycemia and/or reducing serum glucose levels in a patient that includes administering to the patient a therapeutically effective amount of colesevelam or salts thereof.
U.S. Pat. No. 6,733,780 discloses a compressed tablet comprising a hydrophilic core comprising at least or about 95 weight % of poly (allylamine) or a salt thereof and a water-based coating comprising cellulose derivative and plasticizing agent. The patent discloses coating composition comprising hydroxypropylmethylcellulose and a plasticizer. The disclosed coating composition contains at least 23% of diacetylated monoglyceride as a plasticizing agent.
The U.S. Patent Application No. 2010/0008988 discloses pharmaceutical compositions comprising less than about 95% by weight of aliphatic amine polymers of sevelamer hydrochloride, sevelamer carbonate and colesevelam hydrochloride, and methods of preparing pharmaceutical compositions thereof.
The U.S. Patent Application No. 2010/0330175 discloses a pharmaceutical composition comprising dry cross-linked polyallylamine and water soluble excipient comprising polyols and polyethylene glycol.
The U.S. Patent Application No. 2011/0159087 discloses a pharmaceutical composition comprising wet granulated bile acid sequestrants composition, wherein the composition is free of reducing sugar.
The colesevelam hydrochloride tends to be very hygroscopic and thus will swell immediately upon contact with the inside of the mouth. Thus it was believed that coating such tablets with aqueous based coating would be difficult because the hygroscopic tablets would swell during the coating process.
The prior arts disclosure suggests that use of a relatively high amount of diacetylated monoglyceride as plasticizing agent in coating composition to overcome the tablet-swelling problem and to stabilize the pharmaceutical compositions of poly allylamines or a salt thereof.
Thus, there still exists an enduring need to develop an improved and stable pharmaceutical composition of aliphatic amine polymers which will provides an alternative to existing formulation of colesevelam hydrochloride.

Oral pharmaceutical composition of aliphatic amine polymer or salts thereof


A metal detector has one or more feedback loops to control its repeating transmit signal cycle so that there is no reactive voltage drop across the transmit coil of the metal detector during at least one receive period of the metal detector.

The general forms of most metal detectors which interrogate soils are either hand-held battery operated units, conveyor-mounted units, or vehicle-mounted units. Examples of hand-held battery operated units include detectors used to locate gold, explosive land mines or ordnance, coins and treasure. An example of a conveyor-mounted unit is a fine gold detector used in ore mining operations, and an example of a vehicle-mounted unit includes a detector to locate buried land mines.
These electronic metal detectors usually include transmit electronics for generating a repeating transmit signal cycle, which is applied to an inductor, for example a transmit coil, which transmits a resulting alternating magnetic field (also known as a transmit magnetic field).
Time-domain metal detectors usually include switching electronics, within the transmit electronics, that switches various voltages from various power sources to the transmit coil for various periods in a repeating transmit signal cycle.
Metal detectors contain receive electronics which processes a receive magnetic field to produce an indicator output signal, the indicator output signal at least indicating the presence of at least some metallic targets under the influence of the transmit magnetic field.
Traditional PI (Pulse Induction) metal detectors are time-domain detectors, having a plurality of switches for switching at least first and second voltages from power sources, and zero volts for various durations, to generate a repeating transmit signal cycle with a fundamental frequency usually being in the range from tens of Hz to several kHz. The second voltage from a second power source is usually a low negative voltage, −6V for example, and is switched to the transmit coil during a low-voltage period, immediately followed by a back-emf period (a high-voltage period) of a first high voltage, for example +180V, switched from a first power source to the transmit coil usually via a forward-biased diode, then a zero-voltage period following the high-voltage period. The transmit electronics presents a low source impedance to the transmit coil during the low-voltage period and back-emf period, assuming that the coil is connected to the first power source, but presents a high impedance during the period in which critically damped decay of the back-emf occurs, and during the zero-voltage period when no transmit coil current flows and a magnetic signal is received by the receive electronics. During these high impedance periods, the said switching electronics output impedance is usually a function of the capacitance of the switching electronics in parallel with a resistor (e.g. 500Ω) whose value is usually selected to critically damp the self-resonance of the transmit coil connected to transmit electronics. As this period of relatively high impedance commences with a decay of a pulse induction back-emf period, the receive signal will contain a reactive component (X) during this decay period. Hence, to avoid contaminating the receive signal with this X component, usually most, if not all, of the receive signal processing of sampling, or synchronous demodulation, is delayed so as to occur during the period of zero-voltage after the back-emf has substantially decayed.
Eddy currents induced in metallic targets, such as small gold nuggets and fine gold chains, have short decay periods. The delay of the sampling, or synchronous demodulation, of the receive signal after the back-emf periods results in reduced sensitivity to those targets harbouring eddy currents with short time constants. However, the delay cannot be made too short because contamination of the receive signal with X component occurs if the receive sampling occurs when the transient output from the receive coil is significant. Hence, if the duration of the transient output from the receive coil can be reduced, the delay can be reduced, and targets with faster time constants targets can be detected without contamination from X.
A possible solution is detailed in WO2009/155668 where the repeating transmit signal cycle is monitored and controlled such that the receive signal is processed during a zero reactive voltage period during which a constant non-zero current is flowing through the transmit coil. As it is a zero reactive voltage period, there will be no contamination from X when the receive signal is processed. To create such a zero reactive voltage period, WO2009/155668 discloses a switched rectangular repeating transmit signal cycle.
The present invention teaches an alternative to the switched rectangular repeating transmit signal cycle.

Transmit signal of a metal detector controlled by feedback loops