A system and method for creating an authentication mark on a recording medium by depositing marking material on a medium in an image area to create a marking material image and to create a marking material authentication image. The method comprises (a) depositing marking material directly onto a recording medium in an image area to create a marking material image and in an authentication image area to create a marking material authentication image, wherein the marking material is an ultraviolet curable phase change ink composition comprising an optional colorant and a phase change ink vehicle comprising a radiation curable monomer or prepolymer; a photoinitiator; a reactive wax; and a gellant; (b) depositing a predetermined amount of additional marking material upon the authentication image area to increase an amount of marking material associated with the marking material authentication image in the authentication image area; and (c) curing the marking material upon the recording medium such that the fixed marking material associated with the authentication image area is a tactilely perceptible authentication mark, the fixed marking material associated with the tactilely perceptible authentication mark having a first height, the first height being tactilely perceptible.

Disclosed herein are ultra-violet curable gellant inks for tactile and regular print applications, in specific embodiments as security features for signature and document authentication. Also described is a method for forming signature and document authentication security features with the described ultra-violet curable gellant inks.
Document authentication is an increasingly important issue, such as for agencies, including government organizations that frequently issue secure documentation. For example, Ontario Driver's Licenses have recently employed raised text signatures, birthdates, and license numbers for security purposes. See, for example, http://news.therecord.com/News/CanadaWorld/article/279991.
With the general availability of high quality color reproduction, distinguishing an original from a copy and verifying, for example, a signature, on the original has become more difficult. More specifically, digital printers, scanners, and image editing software have made it possible for copies of legitimate documents to be made that are difficult to distinguish from the original.
One conventional approach to authenticating documents is the use of machine readable encoded data which is rendered onto a document or other physical media along with other information.
For example, authenticating information can be encoded into thousands of tiny, individual glyph elements. Each element consists of a small 45 degree diagonal line, as short as 1/100th of an inch or less, depending on the resolution of the printing and scanning that is used. Each glyph represents either binary 0 or binary 1, depending on whether the glyph slopes to the left or right. Sequences of glyphs can be used to encode numeric, textual, or other information. The glyphs are grouped together on the page, where the glyphs form unobtrusive, evenly textured gray areas, similar to a half-toned picture.
Another conventional approach to the problem of verifying document authenticity is the use of authenticating information embedded in a print, for example, a seal or a date and time. The embedded authenticating information catches the light when the print is tilted and can be seen as an additional and separate image. Moreover, watermarks, conventionally, have also been used to authenticate a document.
These various conventional methods of verifying a document share the feature that it is very difficult to reproduce the authenticating feature of the original on a conventional copier or scanner. Therefore, a copy of the original can be distinguished from the original.
However, the conventional methods of verifying a document have drawbacks. For example, glyphs need a device to decode the authenticating information. Moreover, conventional watermarks need a proper source of light to discern the authenticating information. In these various conventional methods, outside intervention; e.g., from either a machine (optical reader) or a light source; is needed to detect or discern the authenticating information.
Commonly assigned, co-pending U.S. patent application of Peter M. Kazmaier, Hadi K. Mahabadi, Paul F. Smith, Chris A. Wagner, Gabriel Iftime, and Tyler B. Norsten, Ser. No. 11/613,759, entitled "Tactile Security Feature for Document and Signature Authentication," filed Dec. 20, 2006, which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a system and method create an authentication mark on a recording medium by depositing marking material on a medium in an image area to create a marking material image and to create a marking material authentication image. A predetermined amount of additional marking material is further deposited upon the medium in the authentication image area to increase an amount of marking material associated with the marking material authentication image in the authentication image area. The fixed marking material associated with the authentication image area is a tactilely perceptible authentication mark wherein the fixed marking material associated with the authentication mark has a height, with respect to a surface of the medium that is tactilely perceptible.
U.S. Pat. No. 6,644,763 describes a method for creating raised and special printing effects using ink jet technology. The method includes the steps of depositing a light curable photo-polymer material on the area selected for the printing effects, and curing the area. The amount of material to be deposited corresponds to the area selected for the printing effects and the height of the raised area relative to the medium on which the photo-polymer material is deposited. See the Abstract.
U.S. Pat. No. 5,627,578 describes a method and device for raised letter or graphics printing, by means of a sprayed wet ink deposition on a print recording medium. Subsequent dispensing of thermographic powder thereon, with adherence of the powder only to the wet ink, followed by heating to a fixing temperature of the powder, results in the raised lettering or graphics. A standard portable ink jet printer of the bubble jet type, controlled, with graphics software control, by a personal computer, provides the requisite non-contacting ink deposition. The dispensing cartridges of the ink jet printer are provided with non-contact-drying ink formulations (with two or more separate colors, if desired) for the portion of graphics or printing which is to be in raised form. A thermographic powder dispenser and heating member is connected to the output of the ink jet printer, or integrated therewith for completion of the raised printing process. Raised and non-raised printing is also possible by use of separately dispensed drying and non-drying inks. See the Abstract.
Ink jet printing devices are known in the art. For example, ink jet printing devices are generally of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field that adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium. There are generally three types of drop-on-demand ink jet systems. One type of drop-on-demand system is a piezoelectric device that has as its major components an ink filled channel or passageway having a nozzle on one end and a piezoelectric transducer near the other end to produce pressure pulses. Another type of drop-on-demand system is known as acoustic ink printing. As is known, an acoustic beam exerts a radiation pressure against objects upon which it impinges. Thus, when an acoustic beam impinges on a free surface (that is, liquid/air interface) of a pool of liquid from beneath, the radiation pressure which it exerts against the surface of the pool may reach a sufficiently high level to release individual droplets of liquid from the pool, despite the restraining force of surface tension. Focusing the beam on or near the surface of the pool intensifies the radiation pressure it exerts for a given amount of input power. Still another type of drop-on-demand system is known as thermal ink jet, or bubble jet, and produces high velocity droplets. The major components of this type of drop-on-demand system are an ink filled channel having a nozzle on one end and a heat generating resistor near the nozzle. Printing signals representing digital information originate an electric current pulse in a resistive layer within each ink passageway near the orifice or nozzle, causing the ink vehicle (usually water) in the immediate vicinity to vaporize almost instantaneously and create a bubble. The ink at the orifice is forced out as a propelled droplet as the bubble expands.
In a typical design of a piezoelectric ink jet device, the image is applied by jetting appropriately colored inks during four to eighteen rotations (incremental movements) of a recording medium, such as an image receiving member or intermediate transfer member, with respect to the ink jetting head. That is, there is a small translation of the print head with respect to the recording medium in between each rotation. This approach simplifies the print head design, and the small movements ensure good droplet registration. At the jet operating temperature, droplets of liquid ink are ejected from the printing device. When the ink droplets contact the surface of the recording medium, they quickly solidify to form a predetermined pattern of solidified ink drops.
Ink jet printing processes may employ inks that are solid at room temperature and liquid at elevated temperatures. Such inks may be referred to as solid inks, hot melt inks, phase change inks and the like. For example, U.S. Pat. No. 4,490,731, the disclosure of which is totally incorporated herein by reference, discloses an apparatus for dispensing solid ink for printing on a recording medium such as paper. In thermal ink jet printing processes employing hot melt inks, the solid ink is melted by the heater in the printing apparatus and utilized (jetted) as a liquid in a manner similar to that of conventional thermal ink jet printing. Upon contact with the printing recording medium, the molten ink solidifies rapidly, enabling the colorant to substantially remain on the surface of the recording medium instead of being carried into the recording medium (for example, paper) by capillary action, thereby enabling higher print density than is generally obtained with liquid inks. Advantages of a phase change ink in ink jet printing are thus elimination of potential spillage of the ink during handling, a wide range of print density and quality, minimal paper cockle or distortion, and enablement of indefinite periods of nonprinting without the danger of nozzle clogging, even without capping the nozzles.
The use of ink jet printers in forming raised printed images is also known, for example, as indicated in U.S. Pat. Nos. 6,644,763 and 5,627,578 above. However, these printers for forming raised images are typically dedicated machines designed and used solely for raised print applications, such as forming Braille images. Where a user requires only a certain portion of print jobs to be done utilizing raised print, it can be costly for the user to have two print devices, one strictly for the raised print jobs.
In general, phase change inks (sometimes referred to as "hot melt inks") are in the solid phase at ambient temperature, but exist in the liquid phase at the elevated operating temperature of an ink jet printing device. At the jet operating temperature, droplets of liquid ink are ejected from the printing device and, when the ink droplets contact the surface of the recording medium, either directly or via an intermediate heated transfer belt or drum, they quickly solidify to form a predetermined pattern of solidified ink drops.
Phase change inks for color printing typically comprise a phase change ink carrier composition which is combined with a phase change ink compatible colorant. In a specific embodiment, a series of colored phase change inks can be formed by combining ink carrier compositions with compatible subtractive primary colorants. The subtractive primary colored phase change inks can comprise four component dyes or pigments, namely, cyan, magenta, yellow and black, although the inks are not limited to these four colors. These subtractive primary colored inks can be formed by using a single dye or pigment or a mixture of dyes or pigments. For example, magenta can be obtained by using a mixture of Solvent Red Dyes or a composite black can be obtained by mixing several dyes. U.S. Pat. No. 4,889,560, U.S. Pat. No. 4,889,761, and U.S. Pat. No. 5,372,852, the disclosures of each of which are totally incorporated herein by reference, teach that the subtractive primary colorants employed can comprise dyes from the classes of Color Index (C.I.) Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, and Basic Dyes. The colorants can also include pigments, as disclosed in, for example, U.S. Pat. No. 5,221,335, the disclosure of which is totally incorporated herein by reference. U.S. Pat. No. 5,621,022, the disclosure of which is totally incorporated herein by reference, discloses the use of a specific class of polymeric dyes in phase change ink compositions.
Phase change inks have also been used for applications such as postal marking, industrial marking, and labeling.
Phase change inks are desirable for ink jet printers because they remain in a solid phase at room temperature during shipping, long term storage, and the like. In addition, the problems associated with nozzle clogging as a result of ink evaporation with liquid ink jet inks are largely eliminated, thereby improving the reliability of the ink jet printing. Further, in phase change ink jet printers wherein the ink droplets are applied directly onto the final recording medium (for example, paper, transparency material, and the like), the droplets solidify immediately upon contact with the recording medium, so that migration of ink along the printing medium is prevented and dot quality is improved.
While known compositions and processes are suitable for their intended purposes, a need remains for a method that enables authentication of an original document without the utilization of outside intervention; e.g. from either a machine (optical reader) or a light source. Moreover, it is desirable to provide a method that enables authentication of an original document through tactile perception. Furthermore, it is desirable to provide a method that enables authentication of an original document through tactile perception while preventing the authenticating information of the original document from being reproduced using conventional scanners and printers. Further, a need remains for a robust marking material compatible with a printing device that can produce regular text and tactile security features.
The appropriate components and process aspects of the each of the foregoing U.S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof.

This patent is subject to a terminal disclaimer.

Ultra-violet curable gellant inks for tactile and regular print applications for signature and document authentication


A work piece holding apparatus uses a magnetorheological fluid for holding a work piece firmly for machining process and/or measurements. The apparatus includes a cell with a hollow space in it and magnetorheological fluid is put into the hollow space. A special fixture with a hollow space in it is used to hold a work piece by screws in the wall or walls. The fixture with a work piece in it is fastened inside the cell dipped in magnetorheological fluid to absorb the extra force beyond the holding power supplied by magnetorheological fluid alone. It then overcomes any climbing that may happen during any process. A magnetic field is supplied to the cell to make the magnetorheological fluid work. It is well known that if a magnetic field is applied to a magnetorheological fluid, the viscosity of the fluid will be increased tremendously and behaves almost like a solid. A pressure applied in this apparatus to the magnetorheological fluid while the magnetic field is "on" will increase the viscosity of a magnetorheological fluid many times. The pressurized magnetorheological fluid supplies a large average pressure (holding force) to a work piece, and the special fixture mentioned then absorbs the overshoot caused by the machining process and/or performing measurements. This invention makes the magnetorheological fluid enter practical industrial applications especially in fixture apparatus applications.

The present invention refers to a fixture apparatus that uses a combination of magnetorheological fluids and a special fixture to hold irregular shaped as well as regular shaped work pieces for precision machinery and measurements or other applications that require such apparatus.
It is an applied apparatus making use of a magnetorheological fluid or magneto-viscous fluids. The viscosity of the fluids changes upon application of a magnetic field produced either by a permanent magnet or an electromagnet. A specially designed mechanical fixture is used to hold any regular or irregular shaped work pieces.
In this apparatus, the magnetorheological fluid supplies the average pressure to the work piece that is fastened into it. The special fixture absorbs the extra force, preventing movement or climbing of the work pieces inside the apparatus during machining process.
Previously, a work piece to be machined with an irregular shape was fixed by clamps or some fixtures. Because they solely rely on the force from the clamps or fixtures, the process can cause permanent damage to the work piece. Another way was using a low-melting point metal alloy to hold a work piece by melting the alloy to liquid form, then dipping the work piece into the melted alloy, and then cooling the alloy to hold the work piece. This heating and cooling process will introduce strains in the work piece. Most of the low-melting point alloys have a harmful high vapor pressure, which will damage to the health of the personnel involved and will pollute the environment in the long run.
This invention has solved the long unsolved problem in industry--to firmly hold an irregular shaped work piece in a fixture to perform precision machining and/or measurements without introducing permanent deformation in the work piece or other damages, especially when the work piece is made of heat sensitive or non-magnetic materials. The invented apparatus, naturally, works even better for conventional work pieces with regular shape.
This invention has made magnetorheological fluids enter practical industrial fixture applications. Besides using the applied conventional magnetorheological fluid, a pressure in one or more directions, especially in the magnetic field direction is applied. This will greatly increase the strength of the fluid (i.e., the hold force of the fluid). Most importantly, a special fixture is used to accurately position and hold a work piece inside magnetorheological fluids to prevent the work piece from climbing which is a fatal drawback to the practical applications of magnetorheological fluids. Therefore, this invention overcomes the drawback of conventional fixture apparatus. This makes practical application of magnetorheological fluids in industry or research institutes possible. The obvious advantages of the apparatus compared with other apparatus available are:
i. The phase of a magnetorheological fluid is reversible with the field on or off, which is convenient to use. It can hold any irregular as well as regular shaped work piece firmly for precision machining and/or measurements. PA0 ii. Since no heating or cooling cycle is introduced into the system during the process, the least amount of damage to the work piece is introduced. PA0 iii. The work piece can be any material: metals or non-metals and magnetic materials or non-magnetic materials. PA0 iv. Because magnetorheological fluid is a very good shock absorbing material, the apparatus will reduce the vibration in the work piece due to the processes (i.e., cutting, milling or grinding process). PA0 v. It is environmentally safe.

Magnetorheological fluid work piece holding apparatus


A decoder (100) is disclosed, which selectively reconstructs at least one predetermined data unit out of a coded bit stream (c). The decoder (100) includes a parsing unit (120) to search and parse unambiguous information (up) characterizing the at least one predetermined data unit uniquely. Next, the parsing unit (120) provides this parsed information (up) either directly to a decoding unit (130) or to a look-up table (140) such that the decoding unit (130) could reconstruct the predetermined data unit directly out of the coded bit stream (c) based on the parsed information (up) without decoding and reconstructing the coded bit stream (c) completely. Optionally, a specification unit (110) provides an start position (us) of the coded bit stream (c) to the parsing unit (120) used for starting the search. Therewith, data traffic, computation time and memory resources could be saved for decoding and displaying e.g. compressed JPEG pictures.

Coding schemes are well known in the art. Coding schemes are used to transform information into a more efficient structure for several purposes. As for example, compression coding schemes are used to minimize the size of data including the information, whereas transport coding schemes are used to increase the differences in the information. Other important purposes could be to optimize energy, to increase the recognition of the information or to increase the robustness against outer influences.
An information bit stream is assembled out of code sequences. A code sequence is a predetermined alignment of data bits, as the most minimum interpretable information unit, to mechanically refer to a denotation of a real circumstance. Normally, in an information bit stream all code sequences comprise a fixed length. Each code sequence represents a data symbol. A data symbol is an interpretable link to the denotation of the real circumstance for a final user or a final using unit. As for example, a single letter of the alphabet as data symbol is an interpretable information for a user. The representation by an unique 8-bit code sequence is the calculation reference for a computer.
To point out the disadvantages of the prior art, the present patent application now describes exemplary entropy coding schemes. However, this should not be taken in a limiting purpose. The problems are also derivable for all other coding schemes.
Due to an unequal occurrence of the code sequences included in the information bit stream, the information bit stream often comprises more data bits than necessary to file the interpretable information. The entropy of a data bit is a value quantifying the interpretable information represented by one data bit in the information bit stream. Accordingly, entropy coding schemes commonly take the advantage of the unequal occurrence of code sequences in the information bit stream, and form new code sequences by reallocating short code sequences to relatively frequently occurring data symbols and long code sequences to relatively occasionally occurring data symbols. With the new code sequences a coded bit stream is assembled increasing the entropy and thus the information content, of the single data bits in the coded bit stream.
Entropy coding schemes are divided into several categories, wherein statistical methods and dictionary methods are best known. Statistical methods only analyze the occurrence of single data symbols in the information bit stream, whereas dictionary methods analyze the occurrence of whole data symbol chains. In addition, run length coding schemes are also well known coding schemes. The principle is to count consecutive occurring data symbols and to indicate only the data symbol itself and the amount of its consecutive occurrence. However, this coding scheme requires an appropriate information bit stream being provided by e.g. picture data.
Other coding schemes take other pre-requirements to assemble a coded bit stream out of a given information bit stream. As for example energy optimizing coding schemes calculate the overall energy of the information bit stream and minimize the overall energy in the new digital bit stream. Accordingly, robustness increasing coding schemes verify the information distance between the single code sequences in the information bit stream and increase the information distance between all possible coding sequences in the coded bit stream. The basic principle of a coding scheme, namely allocating new code sequences to data symbols of an information bit stream is the same, every time.
A conventional decoder reconstructs the information bit stream out of the coded bit stream. Usually, a header added to the beginning of the coded bit stream provides all necessary information to reconstruct the information bit stream and respectively the original code sequences. In case of a conventional entropy decoding scheme, this information comprises at least a coding table for a code bit stream coded by a statistically coding method and a dictionary for a coded bit stream coded by a dictionary based method. That is, prior reconstructing the information bit stream out of a coded bit stream, the conventional entropy decoder reads out information provided by the header of the coded bit stream.
The several data symbols in the information bit stream establish a data unit. A data unit is an interpretable alignment of data symbols, e.g. executable programs, pictures and texts. Usually, an information bit stream comprises a plurality of data units. However, the coded bit stream comprises code sequences of an unequal length such that the conventional decoder is not able to determine the positions of the single data units in the coded bit stream, and the coded bit stream appears as one single data unit first. Therefore, if only one predetermined data unit is needed to be decoded out of the coded bit stream, usually this data unit is not selectable until all data units prior to this data unit are decoded. Therefore, the worst case is that the conventional decoder needs to reconstruct the whole information bit stream before a designated data unit is determinable. Thus, considering all of the involved components within a coded bit stream, the conventional decoder has to handle a huge amount of data and needs a lot of computation steps to reconstruct only one designated data unit. Moreover, the information bit stream must be stored somewhere, increasing the demand on memory. That is, the conventional decoder is extremely time and hardware consumptive in decoding only a few data units out of a coded bit stream comprising a plurality of data units.
A further problem could occur when a data unit is variable in size. That is, the data symbols coded in the coded bit stream keep constant, but the desired data unit is composed of different data symbols in every new decoding step. One known example is when only a section of an image should be displayed. The image section is the data unit to be decoded. It depends on a default value, which might be provided by e.g., a user. In other words, in each time an image section is to be reconstructed out of the coded bit stream, the picture pixels vary as data symbols-vary. Especially in applications with limited memory resources, it is not suitable to store a complete image for selecting only a section of the image.
One solution is to provide a directory in the header of the coded bit stream. Such a directory should store the start points of all data units within the coded bit stream. However, a directory is only reasonable, if the structure of the data units coded in the coded bit stream is manageable in amount and size. In other words, if the coded bit stream comprises a lot of small data units, the directory gets large, such that in case of entropy encoding, no overall compression is achieved at all. Even worse, the new stream size might exceed the size of the original uncompressed data. Moreover, such a directory is not suitable to all coding schemes. Especially coding schemes used to transmit uncoded data bits as sparse as possible cannot take advantage of a directory, because the directory cannot be encoded.
A popular example for a very large amount of small-sized coded data units in a coded bit stream is the JPEG-format used in the fields of image processing. JPEG is a lossy compression method described by the ISO/IEC 10918 standard. JPEG codes an information bit stream with the aid of different coding and compression tools. This method is a very suitable example to point up the disadvantages of conventional decoders.
A digital picture is a two-dimensional area of pixels. Each pixel is a data symbol representing a color within a color table. The digital picture is therefore an information bit stream with a plurality of data symbols according to the picture pixels. The color table is usually based on the RGB color model, being an additive color model. That means that a color value is assembled by weighting and adding basic colors. In the case of the RGB color model, the basic colors are red, green, and blue. The weighting factor of a basic color is named "color level," hereinafter simply called "level."
To compress information bit streams in an efficient way, most compression standards like JPEG, firstly transforms the colors of the digital picture from the RGB color model into the YCbCr color model. The YCbCr is also an additive color model, wherein a color value is assembled by a luminance component describing the gray scaling of a picture and a red chrominance difference component as well as a blue chrominance difference component describing the red and blue scaling of a picture, wherein the red chrominance and the blue chrominance are color difference signals. That is, the original information bit stream is split up into three information bit streams describing the luminance component, the red chrominance difference component and the blue chrominance difference component of the digital picture.
Secondly, in the most simple way, the red chrominance difference component and the blue chrominance difference component are down-sampled due to the less sensitivity of the human eye against color contours, such that the information bit stream according to the red chrominance and the blue chrominance are transformed accordingly. In case of a mere gray scaled digital picture, this step is omitted.
Thirdly, the digital picture is split up into successional groups of 8×8 pixel blocks. The characteristics of the 8×8 pixel blocks are included in at least one minimum coding units, hereinafter called MCUs. Accordingly, each information bit stream describing the digital picture either in the luminance component, in the red chrominance difference component or in the blue chrominance difference component is divided and allocated such that each information bit stream is divided accordingly into a plurality of 8×8 blocks. In general the corresponding 8×8 blocks of the three components can be either coded interleaved in one MCU or separate into three different, non-interleaved, MCUs.
Fourthly, each 8×8 block of an MCU is transformed by a two-dimensional discrete cosine transformation, hereinafter called DCT. Without going deeply into the mathematical background, as a result, the DCT outputs one weighting factor for a constant level basis block, hereinafter called DC-basis block, and 63 weighting factors for 63 varying basis blocks, hereinafter called AC-basis blocks. FIG. 1 shows all possible gray scaling 8×8 basis blocks used to reconstruct the gray part of an 8×8 pixel block in a weighted superposition. The weighting factors outputted by the DCT, hereinafter called DCT-coefficients, allows the DC- and AC-basis blocks to be selectively intensified or weakened, such that each 8×8 block of an MCU could be assembled by a superposition of the DC-basis block and the 63 AC-basis blocks based on the DCT-coefficients. As for the signal processing, the code sequences for each MCU describing the color values in the selected (e.g. YCbCr) color model are replaced by code sequences for each MCU describing the weighting factors of the DCT coefficients. It is important to note that the DC- and AC basis blocks themselves are not the result of the two dimensional cosine transformation, but of the weighting factors. JPEG stores the DCT-coefficient of a DC-basis block differentially in respect to a DC value of a preceding 8×8 block and the DCT-coefficients of the AC-blocks absolutely in the information bit stream.
Fifthly, in a quantization step, all DCT-coefficients needed to describe a 8×8 pixel block of a MCU are sorted, such that the DCT-coefficient belonging to the DC-basis block or slowly varying AC-basis blocks are stored in a consecutive manner. The sorting is performed by a specific scan path, called a ZigZag scan, in a matrix. DCT-coefficients according to the DC-block and to slowly varying AC-blocks are now typically divided by small quantization values. And DCT-coefficients according to strongly varying AC-blocks are typically divided by high quantization values. This division step tracks the basic idea that the human eye is more sensitive to slowly varying frequencies than for to strongly varying frequencies. The quantized DCT-coefficients are rounded to integer numbers. Summarized, a set of quantized DCT-coefficients representing reduced weighting factors for one DC-basis block and 63 AC-basis blocks now define each MCU 8×8 block. That is, the information bit stream originally including color values to describe the digital picture now includes quantized DCT-coefficients. However, until now, only the data symbols, themselves, where transformed into a suitable structure. From now, the data symbols needs to be coded to form a coded bit stream.
Therefore, sixthly, the information bit stream describing the digital picture colors in the selected color model (e.g. YCbCr) are now connected to one information bit stream in such a way, that the code sequences according to the first 8×8 pixel blocks in the upper left position are firstly inserted and the code sequences according to the last 8×8 pixel blocks in the bottom right position are finally inserted. This single information bit stream is entropy and run-length encoded. The quantization of the DCT-coefficients typically generates a lot of data symbols with a level of zero in succession, hereinafter called successive zero levels. The successive zero levels are counted and run length encoded. The result is an intermediate coded bit stream comprising runs and levels. The runs correspond to the amount of successive zero levels replaced at the according position in the intermediate coded bit stream and the levels are the non zero levels at the according position in the intermediate bit stream. Finally, the intermediate coded bit stream is statistically encoded to a coded bit stream to further increase the entropy.
FIG. 2 shows a block diagram describing a conventional decompressor reconstructing an information bit stream according to a digital picture compressed and coded by the JPEG-compression method, and FIG. 3 shows an image of a ROI indicating the visual position an digital picture divided by 8×8 pixel blocks.
A coded bit stream c comprising the JPEG-compressed digital picture is received at a header parser 10 and a decoder 11. The header parser 10 reads out a header included in the coded bit stream c to provide information such as the code tables and the quantization values to the decoder 11 as well as to the quantizer 12 to be applied. Next, the decoder 11 decodes the intermediate coded bit stream including the runs and levels generated during the run length coding. As already mentioned, run length coding and statistic encoding are both coding schemes. However, the stress of the present patent application is directed to decoding methods in general, such that it might be more useful to omit one of the coding schemes used during the JPEG-compression. From now, the run-length encoding method is therefore not regarded within the JPEG-compression. This however does not limit the facts of the case. It is irrelevant whether one or a plurality of coding schemes is used. The run length encoding is only omitted for concise purposes and to get the circumstances better understandable. Therefore, the decoder 11 directly outputs an information bit stream DCT′ including quantized DCT-coefficients. The information bit stream DCT′ including the quantized DCT-coefficients is forwarded to the inverse quantizer 12 multiplying the quantized DCT-coefficients by the respective quantization values to create an information sequence DCT″ including multiplied quantized DCT-coefficients. Finally, an inverse transformation unit 13 reads out all multiplied quantized DCT-coefficients from the provided information bit stream DCT″ to construct first all MCUs based on the multiplied quantized DCT-coefficients and then the 8×8 pixel blocks. That is, the inverse transforming unit 13 creates an information bit stream including the pixels of a digital picture.
However, many applications aim to display only a section of a digital picture. Such a section is a region-of-interest, hereinafter called ROI. Especially in mobile communication it is a necessity to select ROIs, due to the limited hardware resources of the mobile devices. Recently, there has been a development to provide mobile devices with photo cameras. Photo cameras, themselves, are aimed to provide a high resolution shot photograph. However, the display of a mobile device only provides less resolution. Therefore, the display of an ROI is a suitable way to display a photograph with a higher resolution on a mobile device display.
The conventional decompressor needs to completely reconstruct an information bit stream comprising the pixels of a digital picture. Then, the ROI is selectable by an ROI selector 14. If it is wished to move the ROI through the digital picture, a large amount of data has to be managed, even if the information bit stream comprising the pixels of the digital picture is stored temporarily in a memory. That is, juddering could occur during the movement of the ROI through the digital picture.
A directory in the header of the coded bit stream c indicating the start positions of the single MCUs within the coded bit stream c might be an appropriate way to directly decode the quantized DCT-coefficient out of the information bit stream DCT′ needed to display the ROI. However, this is technically useless, as shown in the following example. A YCbCr 4:2:0 VGA-picture with a resolution of 640×480 pixels is divided into 1200 MCUs respectively 9600 8×8 blocks. On the other hand, the resulting coded bit stream c comprises around 500000 bits in case of a common compression rate of 10. In this case, each position in the header requires at least a 19 bit address such that the final directory size of the header extents to around 12 Kilobyte if the start positions of each 8×8 pixel block is indicated. The JPEG-compressed picture itself has a size of around 600 Kilobyte. That is, much more than 2% of the coded bit stream c is consumed for an appropriate directory. Such directory must be stored uncompressed. This means, even if the quality of the JPEG compressed digital picture is reduced to further minimize the size of the coded bit stream c, the directory size keeps constant.
That is, as shown on the example of a JPEG-compressed picture, there is a need to provide an apparatus and a method to decode data units out of a coded bit stream by an arbitrary coding scheme saving memory and resources on the one hand and being able to selectively decode at least one predetermined data unit out of the digital bit stream on the other hand.

Decoder for selectively decoding predetermined data units from a coded bit stream


Methods and structures for detecting touchdown of the read/write head on its recording surface or for detecting other read signal amplitude modulations as proportional to variance of the value of the read channel variable gain amplifier (“VGA”). Variance in the VGA values caused by the standard feedback control electronics associated therewith is proportional to amplitude modulations of the sensed signal picked up by the read channel (or servo read sensor). These amplitude modulations are, in turn, reflective of flying height of the read/write head as well as generally indicative of other parameters of the read channel operation. Touchdown of the read/write head and other parameters of the disk drive operation may therefore be detected as variances in the VGA control values.

1. Field of the Invention
The invention relates generally to disk drive control structures and techniques and in particular relates to improved methods and structures for detecting anomalous conditions within a disk drive. Exemplary anomalous conditions may include, for example: detection of touchdown of the air bearing surface of the read/write head on the surface of the recording medium and detection of quality defects on the surface of the recording medium.
2. Discussion of Related Art
Present day disk drives store and retrieve information on a rotating recording media while a read/write head "flies" in close proximity above the surface of each recordable medium. Typically, multiple such recording surfaces and corresponding read/write heads are integrated within a single disk drive device to allow for enhanced performance and capacity.
The recording media may be either optically encoded or magnetically encoded to store data. In general, an optical recording medium records and retrieves information by altering and then sensing optical properties of the recording medium surface. A magnetically encoded recording surface records and senses magnetic flux changes on the magnetizeable surface of the recording medium. In general, the medium is rotated as the read/write head flies in close proximity above the surface of the recordable medium. Multiple concentric tracks or cylinders are typically configured at incrementing radial positions on the recording medium surface and each track consists of a plurality of bits representing the stored data and associated meta-data.
During normal operation of a disk drive, it is critical that the read/write head should not make contact with the surface of the recording medium for an extended period of time. Such physical contact between the read/write head and the surface of the recording medium may cause permanent damage to the read/write head and/or to the recording medium surface thereby potentially losing previously recorded data and/or disabling the disk drive. To this end, an air bearing surface ("ABS") is designed to maintain a relatively constant "flying height" of the read/write head over the recording medium surface. The mechanical design of the air bearing surface of the read/write head is the principle control mechanism to maintain a safe flying height above the recording medium surface rotating adjacent the read/write head. Since the recordable medium rotates at a relatively constant speed, and since other environmental parameters are relatively stable, the aerodynamic properties of the air bearing surface maintain a substantially constant spacing between the read/write head and the rotating recording medium.
Various control mechanisms are applied to refine control of the flying height of the read/write head above the rotating recording medium. During the manufacture process of a disk drive, it may be desirable to permit touchdown or contact between the read/write head and its corresponding recording medium surface so as to calibrate the feedback control mechanisms used to more accurately maintain a constant flying height. By allowing such contact or touchdown of the read/write head on the recording medium, the feedback control mechanisms for maintaining head flying height may be properly calibrated for a baseline value associated with touchdown or contact with the recording medium surface. Thus, slight variations in mechanical tolerances and electrical properties of the disk drive as well as those of the recording medium surface may be accounted for by calibrating each head for touchdown with its corresponding surface.
Present techniques for determining or detecting such head-surface contact or touchdown during manufacturing test and calibration procedures generally utilize other sensing mechanisms within the disk drive that are indirectly indicative of head touchdown. For example, most presently known touchdown or contact detection mechanisms utilize the position error sensing ("PES") control features of the disk drive to sense the likely occurrence of touchdown between the read/write head and its corresponding recording surface. The PES sensing and control mechanisms of the disk drive perform fine adjustments to properly position the read/write head radially to a desired track or cylinder location. The PES feedback mechanisms senses errors in attempts to read servo information recorded at fixed locations on the rotating recording medium. As the fly height of the read/write head changes, within a few rotations of the recording medium, the position error sensing feedback control mechanism may determine that a significant enough change or trend of changes in the position error signals may represent a head touchdown.
A number of problems arise in existing touchdown detection mechanisms that depend on sensing changes in the PES related signals. First, detecting head touchdown from such a PES feedback loop signal may require multiple rotations of the rotating recording medium due to the relatively slow control feedback loops used in such PES control systems. Permitting multiple revolutions of the rotating recording medium when a head touchdown condition is presently occurring may cause undue wear of the recording surface and/or of the read/write head. In addition, the PES feedback control mechanisms are significantly impacted by the skew angle of the read/write head relative to the present radial track position. The skew angle is the angle of the read/write head relative to the tangential angle of a given track over which the head is positioned. Thus, use of the PES feedback in control mechanisms for the additional purpose of detecting touchdown of the read/write head on its corresponding recording medium surface may be limited to certain specific ranges of radial positions where the skew angle is large. At track locations where the skew angle is small or zero, this approach will have difficulties because there is no tangential force.
It is evident from the above discussion that a need exists for an improved method and structure for detecting touchdown of the read/write head on its corresponding recording medium surface.

Methods and structure for detecting anomalous events in a disk drive using VGA variance


A fluid coupling wherein a tubular coupling member has a first terminal sealingly engageable with an end of a first conduit and a second terminal sealing engageable with an end of a second conduit. The end of the second conduit has a radially outwardly extending retaining flange and the coupling member has a set of radially movable resilient arms which engage the flange when the second terminal is in proper engagement with the end of the second conduit. The arms can be prevented from becoming accidentally disengaged from the flange by one end portion of a sleeve which is reciprocable along and surrounds the coupling member. The sleeve can be releasably locked in a release position in which the arms are free to become disengaged from the flange and/or in a locking position in which the sleeve prevents disengagement of the arms from the flange. The device for locking the sleeve can comprise a clamp which is more or less permanently installed in the sleeve or a clamp which can be completely disengaged from the coupling member and is not connected to the sleeve. A spring can be provided to bias the sleeve to the locking position. The clamp can be omitted if the locking device comprises one or more cams on the coupling member and a follower for each cam; such follower or followers are provided in the sleeve.

The invention relates to improvements in fluid couplings in general, and more particularly to improvements in devices which can be used to rapidly establish or terminate a sealing connection between the ends of two conduits. Still more particularly, the invention relates to improvements in couplings which are designed to establish a readily separably sealing connection between an end of a first conduit (e.g., a hose) and a second conduit (e.g., a pipe or a nipple) having an end with an at least substantially radially extending retaining portion, e.g., with an external flange having a substantially radially outwardly extending retaining surface confronting the other end of the second conduit.
German patent application Serial No. 37 41 250 of Rosch et al. (published Jun. 15, 1989) discloses a coupling which is designed to establish a sealing connection between two conduits, particularly between two conduits which serve to convey fuel in a motor vehicle. The coupling comprises a tubular coupling member a first terminal of which is connectable with an end of one of the conduits and a second terminal of which is connectable with an end of the other conduit. The coupling member carries resilient arms which can engage a retaining portion at the end of the respective conduit, and the coupling further comprises a sleeve which surrounds and is movable axially of the coupling member to and from a locking position in which the arms cannot be disengaged from the retaining portion. One or more sealing elements are interposed between at least one of the terminals and the end of the respective conduit. The external surface of the coupling member is provided with circumferentially extending grooves alternating with ribs, and the internal surface of the sleeve is also provided with alternating ribs and grooves. The sleeve is movable axially of the coupling member to any one of several positions in each of which one or more internal ribs extend into a different set of external grooves, and vice versa. This enables the coupling member to hold the sleeve against unintentional movement all the way to a position in which the coupling member can become disengaged from the retaining portion.
A drawback of the proposal of Rosch et al. is that the sleeve must be made of a material which exhibits a considerable amount of elasticity. Therefore, the assembled coupling cannot stand pronounced stresses, namely axial stresses which suffice to effect radial expansion of the sleeve with attendant expulsion of its internal ribs from the external grooves of the coupling member. Rosch et al. propose to reinforce a portion of the sleeve to prevent such unintentional forcible separation of the coupling member from one of the conduits. Reinforcement of the sleeve contributes to the cost of the coupling. Moreover, a person seeking to assemble the coupling or to separate the coupling member from one of the conduits must exert a considerable force in order to overcome the resistance of mating internal and external ribs.
U.S. Pat. No. 4,451,069 granted May 29, 1984 to Melone discloses a quick disconnect fluid coupling wherein a female member is provided with radially extending latch fingers which are designed to engage a male coupling member. The patentee proposes to employ a locking sleeve which has a set of radially resilient fingers and a ring portion movable to a position in which the fingers of the female coupling member cannot be disengaged from the male coupling member. The patentee further proposes to provide latch means for releasably holding the sleeve in the locking and release positions. The latch means comprises internal ribs on the fingers of the locking sleeve and external grooves in the male member. One of the grooves receives the internal ribs in the locking position of the sleeve, and the other groove receives the internal ribs in the release position of the sleeve. A drawback of the patented coupling is that it must employ complex (and hence expensive) male and female coupling members and a quite complicated sleeve. Moreover, the ability of the coupling to stand axial disengaging stresses is rather limited.


An adaptive feedback control method of a field sequential color display includes converting gray-scale values of a three primary color field of an input image into gray-scale values of a new three primary color field and a dominated color field (D-field); performing sampling; performing a pixel by pixel sum operation for each separated color through color gamut conversion to obtain a color difference sum; performing a feedback control at a bit precision to obtain a minimum color difference sum; and then performing a liquid crystal/backlight synchronization step of synchronizing a liquid crystal signal and a backlight gray-scale value of the input image; or dividing the input image into a plurality of blocks; performing feedback control operations; obtaining a minimum sum in each block to serve as an optical backlight value, thereby reducing a CBU phenomenon, and minimizing or controlling the generated CBUs to reduce the operation loads.

1. Field of Invention
The present invention relates to an image displaying technique, and more particularly to an adaptive feedback control method, suitable for performing an adjustment in real time according to a frame content to achieve a backlight color field with a minimum image color difference, thereby alleviating a color break-up (CBU) phenomenon of a field sequential color (FSC) display.
2. Related Art
A conventional liquid crystal display (LCD) utilises a color filter to achieve full-color effects, but the luminous efficiency thereof is not desirable. Based on a fast-response liquid crystal panel, such as an optically compensated bend (OCB) mode, and a backlight source, such as a high-efficient light-emitting diode (LED), developed in recent years, an LCD with a field sequential color (FSC) mechanism has been achieved. Particularly, the speed for sequentially displaying main color fields of red, blue and green is higher than a time resolution of a response of human eyes, so that the full-color effects can be achieved without requiring any color filter. Through combining the backlight of LEDs with the liquid crystal panel in the OCB mode, an FSC-LCD is expected to become a color LCD with a high luminous efficiency, low power consumption and low material cost.
However, generally, the critical problem of a conventional FSC-LCD lies in a color break-up (CBU) problem. The CBU problem is caused by a relative movement between an object in an image and eyes of an observer, that is, during a saccade interval of human eyes, a signal from human eyes to human brains is suppressed due to a saccadic suppression. Referring to FIG. 1, a CBU image simulated with an RGB FSC is shown. In the CBU image M1 simulated by using three primary color sub-fields R, G and B, the CBU phenomenon can be recognized, and as a result, the definition of the whole image is deteriorated. FIG. 2 is a schematic view of a color image displaying method in a conventional FSC. Referring to FIG. 2, under a circumstance that an observation spot is moved as time elapsed, the CBU phenomenon can be found through a pattern displayed in an FSC color displaying manner. In the FSC color displaying manner, an image is displayed in a time sequence, and a color sequence thereof is "RGB RGB RGB . . . ", in which R represents a red sub-frame, G represents a green sub-frame and B represents a blue sub-frame. Taking a white image W10 as an example, when it requires to display a white image, in the white image W10 as seen from the observation spot, a combination of B, B, and G is presented on one edge W11 (on the left of FIG. 2) of the white image W10 and a combination of R, R, and G is presented on the other edge W12 (on the right of FIG. 2), which is the so-called CBU phenomenon.
Considering the FSC applications, U.S. Pat. No. 5,337,068 has disclosed a FSC display system and a method for forming an image, in which a liquid crystal device is used together with backlights in three colors of red, blue and green. The three backlights emit lights respectively, and then the liquid crystal device simultaneously adjusts the light flux respectively, thereby constituting sub frames in three different colors, and finally, the red, blue and green sub frames are formed into a color frame. As for the conventional FSC system architecture and the method for forming an image, the CBU phenomenon is rather obvious, which can be easily recognized by the observers.
U.S. Pat. No. 6,570,554 has disclosed an LCD, in which sub color fields of three consecutive frames are regularly converted to solve the CBU problem of the conventional FSC-LCD. When the observer tracks an animation object with his/her eyes at the same speed, an integral result of the three consecutive frames is left on the retina of human eyes without generating the CBU phenomenon. Unfortunately, in this method, when the frequency of the green color field is lower than 50 Hz, the human eyes can perceive a flicker phenomenon, and as a result, the frame quality is deteriorated.
Furthermore, U.S. Pat. No. 7,057,668 has disclosed an image signal processing method for alleviating the CBU phenomenon of the FSC. In a display with red, blue, and green LEDs, or an additional white LED, serving as the backlights, when an image signal is input, it is converted into a YCrCb color system. When a CBU phenomenon of the display content is fairly slight, an image frame is displayed in an FSC manner. When the CBU phenomenon of the display content is rather severe, the backlights are adjusted into all white lights, that is, the red, blue, and green LEDs are all turned on to emit lights, or merely the white LED is turned on to emit lights, thereby suppressing the CBU phenomenon. However, when the backlights are all turned on, color filters are still required for achieving the full-color effects of the image.
Furthermore, Jongseo Lee et al. has published an article entitled "Noble Measurement Method for Color Breakup Artifact in FPDs" in IMID/IDMC'06, in which CIE LUV color coordinates are utilised to analyze the CBU phenomenon, and it is defined that a color difference (ΔE) in the coordinates is a factor for quantification of the CBU. However, in the published document, other novel method for improving the CBU phenomenon is not mentioned.
In terms of alleviating the CBU problem, U.S. Pat. No. 6,911,963 has disclosed an FSC display method for reducing the CBU phenomenon, in which a time sequence of brightness information of an input image information with all the display colors is displayed. In order to display the input image information, that is, synchronously changing the display color and the brightness information, one color image is displayed in at least four sub-field intervals in one frame interval, and one picture signal in at least one sub-field interval is a non-primary color picture signal, which is generated by at least two primary color signals in the input picture signal carrying primary color signals. The processing manner includes converting the gray-scale rgb of the image into a statistical graph of tristimulus values XYZs in a CIE1931XYZ color system, and then converting the statistical graph into corresponding tristimulus values XYZs of backlight colors, thereby determining the color of the additional sub-field.
When the above methods are used, the following three conditions must be preset, including:
(1) the CBU easily occurs at a high-frequency portion of a high-brightness (Y value) signal level;
(2) the CBU easily occurs when a frequency of an X value is larger than that of a Z value; and
(3) the CBU easily occurs at a portion with a high Z value, that is, both the X value and the Y value are lower.
Therefore, the color selected from each signal level satisfying the above conditions (1)-(3) is the color of the additional fourth sub-field. However, in order to acquire the color of the fourth sub-field, the statistics of the image must be analyzed first, which is not only time consuming, but also increases the calculation capacity.
In view of the above problems, the inventor has proposed an adaptive feedback control method of an FSC-LCD, so as to overcome the defects of the prior art.

Adaptive feedback control method of FSC display


A 1.times.N fiber optic coupler is formed by assembling a coupler preform including spacer tube means surrounded by an outer glass tube that is concentric with the spacer tube means. A first optical fiber is disposed in an axial bore in the spacer tube means, and N optical fibers are disposed within a gap between the spacer tube means and the outer tube, the first fiber and the N fibers extending through the midregion of the coupler preform. The midregion of the outer tube is heated to collapse it about the fibers, and the central portion of the midregion is stretched to reduce the diameter thereof over a predetermined length. In accordance with the invention, the spacer tube means is glued to the first optical fiber and to the outer tube.

This invention relates to 1.times.N fiber optic couplers (N>2) that are capable of coupling substantially equal amounts of power from an input optical fiber to three or more output optical fibers; it also relates to methods of making such couplers.
Methods of making 1.times.N couplers are disclosed in U.S. Pat. No. 5,017,206 and in U.S. patent application Ser. No. 07/913,390 (D. L. Weidman 6) filed Jul. 15, 1992, now U.S. Pat. No. 5,268,979.
Fiber optic couplers have been formed by assembling a coupler preform comprising two concentric glass tubes having a gap therebetween. The shape and/or size of the inner tube relative to the shape and/or size of the outer tube is such that a plurality of output optical fibers can be equally spaced in the gap. An input optical fiber is disposed in an bore in the inner tube. The input and output fibers extend through the midregion of the resultant coupler preform. The midregion is heated to collapse it about the fibers, and the central portion of the midregion is stretched to reduce the diameter thereof over a predetermined length.
The collapsing of the tube midregion causes the optical fibers just outside the collapsed region to be weakened. This weakened region occurs a few millimeters from the fully collapsed region in the uncollapsed portion of the bore of the outer tube. Pulling on the fiber pigtails extending from the coupler can cause fiber breakage. Moreover, under severe thermal cycling, the weakened region of the fibers has been known to break, primarily because of a thermal coefficient of expansion mismatch between the glue and the glass coupler components.
It has therefore been conventional practice to glue the ends of the outer tube to the fibers to provide those portions of the fibers that extend from the coupler with adequate pull strength. However, since the spacing between the input fiber and the inner glass tube is extremely small, glue applied to an end of the inner tube cannot flow between that tube and the input fiber. Therefore, an insufficient amount of glue contacts the input fiber to provide it adequate pull strength.

Method of affixing optical fiber to coupler


A method for producing a component from a fiber-composite material, wherein a plurality of fiber-tape pieces, which each comprise a thermoplastic fiber-tape piece matrix with fiber-tape-piece fibers embedded therein, are provided, the fiber-tape pieces are picked up in the solid state and arranged so as to form a fiber-tape pattern, a backing layer, which comprises a thermoplastic backing-layer matrix with backing-layer fibers embedded therein, is provided and heated such that the backing-layer matrix softens or melts, a preform is formed from the backing layer and the fiber-tape pattern in that the fiber-tape pattern is applied in the solid state to the heated backing layer and is heated thereby so that the fiber-tape-piece matrices soften or melt such that the preform is in a deformable state in which both the backing-layer matrix and the fiber-tape-piece matrices have been softened or melted, the preform in the deformable state is deformed.

The invention relates to a method for producing a component from a fiber composite material.
DE 102 53 300 A1 discloses a process for producing structural components with a plastic matrix material that is reinforced by glass fibers, wherein intentionally aligned carbon fibers are at least partially provided according to load paths of the component in the loaded state. In particular, the aligned carbon fibers are embedded between two layers of substantially randomly oriented fiberglass structures.
EP 0 491 353 A1 discloses a method, wherein load-path-oriented fiber portions are applied by pressing locally with a pressure roller while also locally heating the fiber tape. This method has the disadvantage that several fiber orientations cannot be applied at the same time. In addition, this method limits the geometric complexity of components.
DE 10 2006 025 280 A1 discloses a method for producing a fiber-reinforced component, wherein a bundle of a continuous fiber is impregnated and this fiber/matrix strand is placed with almost the final contour in a temperature-controlled device over a nozzle by a handling device and thereafter consolidated. In particular, the fiber/matrix strand with the continuous fiber is placed in the mold and in other areas a fiber/matrix strand with long or short fibers.
Fiber composite materials are produced by labor-intensive and cost-intensive processes, wherein the fiber composite material consists of a proportion of fibers and a proportion of a matrix. When processing continuous fiber-reinforced thermoplastics, it is therefore customary to reshape flat intermediate products which already contain a sufficient proportion of thermoplastic matrix in the fiber material. This blank is referred to in particular as a board, wherein the starting material of the board is preferably an organic sheet. For example, an organic sheet is done produced, inter alia, by layering flat semi-finished fiber products which are pressed together with thermoplastic materials in film and/or powder form by applying pressure and temperature
In particular, all forms of thermoplastic materials can be used as a matrix material of the organic sheet. Typical representatives are polyamides, polypropylenes, polyethylene terephthalates, polyether ether ketones, polyphthalamides and thermoplastic polyurethanes.
In particular, an intermediate product, which preferably comprises the fiber material and a thermoplastic matrix material, is referred to as a preform, which passes through the processing conditions or processing states of a semi-finished fiber product from merging all continuous fiber fractions and their matrix components. A preform preferably passes through the processing conditions or processing states at the continuous fiber portion until it is fully formed.
It is customary for an economical production of the starting material of the boards to produce, in a first step, a large-area fiber material in form of a sheet product, from which the board is then cut out. As part of the manufacturing step of this sheet product, a tensile stress on the fiber material is necessary for process control which requires a continuous fiber across the width of the sheet product. The board is thereby limited to a fiber architecture that is constant over the entire surface.
Fibers have enhanced mechanical properties in their longitudinal direction. Therefore, in the mechanical design of the fiber material in the component, the alignment of the continuous fiber material is oriented on and along the load paths of the product. Components can have areas of higher load, with respect to which the wall thickness, the fiber structure and the fiber path are designed. This causes oversized wall thicknesses in the continuous fiber material in surrounding areas of the stress peak, which cannot be avoided due to the way the circuit board is manufactured. However, the cost structure of products of this material class requires economical use of the base material (organic sheet). This leads to a conflict between objectives of economy and mechanical properties of the continuous fiber material.
Methods are known which provide for a direct layering of the endless fiber material on planar or three-dimensional backing-layers, which are subsequently shaped such that the fiber material is disposed in the load path. These methods can be distinguished as methods for processing unconsolidated (dry) fibers and methods for processing consolidated fibers (fibers provided with a matrix). Processes of dry-layering (e.g. TFP: Tailored Fiber Placement) stitch reinforcing fibers with a sewing thread onto a carrier material which are, in the course of further processing, impregnated with a chemically/thermally curing resin and fixed to form a component. The process parameters used for impregnation, such as pressure and temperature, however, lead to an increase in equipment costs.
Processes for load-path-oriented processing of thermos-plastically consolidated semi-finished products are based either on an intimate material connection of the reinforcing fibers to a carrier or on a preliminary fixation of the fiber with subsequent consolidation in a subsequent method step. Among other things, thin tapes can be deposited along paths of the component geometry to be traveled. In this type of process, the geometric complexity is limited by the radii of the continuous fibers that can be deposited and the dimension of the depositing facilities.
If, however, fiber tapes made of continuous fiber reinforcement are laid down along paths on three-dimensional geometries over the length of a component, differences in length between the inside of the curve and the outside of the curve limit the radii that can be deposited error-free and consequently also limit the geometric component complexity.
The application of reinforcing fibers to increase the anisotropy of continuous fiber products is thus known. The known methods have the particular disadvantage that either an intermediate product is created before heating, which results in at least one additional method step and a deterioration of the material properties, or that the reinforcing fiber components are sequentially deposited onto the substrate as a pattern, which also requires an additional method step and reduces the speed of the production line. Furthermore, the use of hot melt adhesives is known, which however leads to a material-inhomogeneous fiber matrix.
On this basis, it is therefore the object of the invention to provide a simpler method for producing a component from a fiber composite material.

Method for producing a component from a fiber-composite material


A holding device for holding an optical element to be ground is arranged such that pressure applied to a receiving face of the optical element on the holder base is made different in the radial direction in order to eliminate deformation, positional deviation or inclination of the optical element due to grinding resistances during grinding or due to high-pressure grinding. An elastic member is employed as an elastic member, or a receiving member capable of absorbing the positional deviation, the inclination, or the like of the optical element during grinding thereof is used.

1. Field of the Invention
The present invention relates to a holding device for holding an optical element to be ground, such as a lens, a prism or the like.
2. Description of the Related Art
Prior arts which relate to holding devices of this kind are disclosed in Japanese Patent Laid-Open No. 121862/1986 and Japanese Utility Model Publication No. 37627/1987.
In accordance with the art disclosed in Japanese Patent Laid-Open No. 121662/1986, there is provided an apparatus of the type which, as shown in FIG. 21, includes a grinding disc 201 for grinding a lens 203 while rotating in a fluctuating manner and a grinding holder 202 which is held such that its radial plane is perpendicular to the central axis of the grinding disc 201, the lens 203 being ground by the grinding disc 201 as it is pressed against the grinding disc 201 by means of the grinding holder 202. In the construction of the apparatus of this prior art, an elastic member 204 is attached to the end face of the grinding holder 202 which opposes the lens 203, and the grinding holder 202 is fitted onto a holder spindle 205 inserted into a holder shaft 206 so as to elastically apply a pressure to the lens 203 to be ground between the grinding disc 201 and the grinding holder 202. Reference numeral 207 denotes bearings for supporting the holder spindle 205 for rotation about the longitudinal axis thereof, and reference numeral 208 denotes a spindle connected to the grinding disc 201.
The feature of the grinding mechanism having the aforesaid arrangement is that the grinding holder 202 having the elastic member 204 at the end facing the lens 203 is fitted onto the holder spindle 205 inserted into the holder shaft 206.
In accordance with the art disclosed in Japanese Utility Model Laid-Open No. 37627/1987, there is provided a lens holding device for use in an apparatus of the type which, as shown in FIG. 22, includes a grinding disc 210 arranged to rotate about the longitudinal axis of the apparatus as indicated by the arrow shown in a lower portion of the figure and a lens moving rod 211 arranged to travel in the horizontal direction while pressing the surface of the grinding disc 210 with its longitudinal axis always kept normal to the surface of the grinding disc 210. This lens holding device comprises an inverted-cup-shaped member 212 secured to one end of the lens moving rod 211 for rotation about the axis thereof, a lens holder 214 removably fitted into the inverted-cup-shaped member 212 and engaged with the edge of the open end of the inverted-cup-shaped member 212 via an elastic member 213, the lens holder 214 being capable of tilting by slight angles with respect to the inverted-cup-shaped member 212, a recess means 216 formed in the lower end portion of the lens holder 214 which is radially inward of the edge of the open end of the inverted-cup-shaped member 212, the recess means 216 serving to securely receive a lens 215 while reducing a moment resulting from the horizontal travel and acting to rotate the lens 215, a bore 217 formed in the lens holder 214 to place the recess means 216 in communication with a space defined in the inverted-cup-shaped member 212, and a communication bore 218 for providing communication between the space defined in the inverted-cup-shaped member 212 and an evacuating pump (not shown) to attract the lens holder 214, hence the lens 216, into the inverted-cup-shaped member 212 by vacuum.
The lens holding device having the aforesaid construction and arrangement is capable of grinding a lens of small diameter and large thickness with high precision and helps to facilitate lense replacement and the alteration of a lens size.
The above-described prior arts, however, have not been satisfactory proposals in that they involve the following problems. The apparatus which relies on the art disclosed in Japanese Patent Laid-Open No. 121862/1986 has no mechanism for restricting radial movement of the lens 203. As a result, while grinding is being performed using a fixed abrasive grinding stone or the like, the lens 203 is pulled in the radial direction by grinding resistances, so that the axis of the lens 203 may deviate to a serious extent.
In contrast, in accordance with the art disclosed in Japanese Utility Model Publication No. 37627/1987, the radial movement of the lens 215 is restricted by the lens holder 214. However, since this lens holder 214 is attracted by vacuum into the inverted-cup-shaped member 212 via the elastic ring 213, the entire lens holder 214 is pulled in the radial direction due to grinding resistances produced during grinding, as in the art disclosed in Japanese Patent Laid-Open No. 121862/1986. This leads to the problems that the axis of the lens 215 deviates and that the elastic ring 213 is excessively compressed over its entire circumference to hinder satisfactory relaxation of elastic forces.
Because of the above-described problems, either of the aforesaid prior arts involves the serious problem that the lens may vibrate during grinding so vehemently as to disable continuation of the grinding or to deteriorate the precision of a ground surface to produce a number of imperfect products.
Conventionally, lenses of the type which can be independently ground have in most cases been subjected to nonblocking grinding (the process of grinding an object while retaining it in a holding device without the use of any adhesive). A typical example of this holder is shown in FIG. 20. In the figure, a holder 142 which constitutes the body of a holding device 141 is provided with a recess having a receiving face 143 which is covered with a receiving member 144 made of elastic material such as rubber or the like, and a lens 145 as an object to be ground is fitted into the recess with the receiving member 144 sandwiched between the lens 145 and the receiving face 143. With the aforesaid construction and arrangement, it is possible to effect nonblocking grinding without impairing the external appearance or the quality of the receiving face 146 of the lens 145 of relatively thick configuration.
In such a conventional holding device for use in a grinding apparatus, however, the overall portion of the receiving member 144 having elasticity is sandwiched and restricted in position between the holder 142 and the lens 145 owing to pressures applied to the lens 145 during grinding thereof. As a result, satisfactory relaxation of elastic force (or uniform deformation of the elastic member) is not achieved. Distorted Newton fringes, which may be produced by the influence of a variation in the strength of grinding pressure, such as an excessive increase in peripheral pressure or central pressure, are not formed in lenses of relatively thick configuration. However, if a lens to be ground has a particular configuration, for example a relatively thin configuration, variations in the strength of the grinding pressure are caused by nonuniform elastic forces. As a result, the lens is deformed and unwanted Newton fringes are formed, so that a high-precision ground surface is not obtained.

Holding device for holding optical element to be ground


A method for fabricating high efficiency CIGS solar cells including the deposition of Ga concentrations (Ga/(Ga+In)=0.25−0.66) from sputtering targets containing Ga concentrations between about 25 atomic % and about 66 atomic %. Further, the method includes a high temperature selenization process integrated with a high temperature anneal process that results in high efficiency.

Solar cells are photovoltaic (PV) devices that convert light into electrical energy. Solar cells have been developed as clean, renewable energy sources to meet growing demand. Solar cells have been implemented in a wide number of commercial markets including residential rooftops, commercial rooftops, utility-scale PV projects, building integrated PV (BIPV), building applied PV (BAPV), PV in electronic devices, PV in clothing, etc. Currently, crystalline silicon solar cells (both mono-crystalline and multi-crystalline) are the dominant technologies in the market. Crystalline silicon (cSi) solar cells must use a thick substrate (>100 um) of silicon to absorb the sunlight since it has an indirect bandgap and low absorption coefficient. The use of a thick substrate also means that the crystalline silicon solar cells must use high quality material to provide long carrier lifetimes. Therefore, crystalline silicon solar cell technologies lead to increased costs. Thin film photovoltaic (TFPV) solar devices based on amorphous silicon (a-Si), CIGS, cadmium telluride (CdTe), copper zinc tin sulfide (CZTS), etc. provide an opportunity to increase the material utilization since only thin films (<10 um) are generally required. The thin film solar cells may be formed from amorphous, nanocrystalline, micromorph, micro-crystalline, polycrystalline, or mono-crystalline materials. TFPV devices may include a single absorber layer for converting light into electricity, or multiple absorber layers with tuned absorption spectra for converting light into electricity in a tandem configuration. The tandem configuration might be a two-terminal device, or a multi-terminal (e.g. four-terminal) device structure. The multi-terminal device structure might be comprised of one stack of layers on one substrate, or involve different stacks of layers on multiple stacked substrates.
TFPV devices provide an opportunity to reduce energy payback time, and reduce water usage for solar panel manufacturing. Typical CdTe and CZTS films have bandgaps of about 1.5 eV and therefore, are an ideal match for the AM1.5G solar spectrum to allow for high efficiencies. The absorption coefficient for CdTe is about 105/cm and the absorption coefficient for CZTS is about 104/cm. CIGS films have bandgaps in the range of 1.0 eV (CIS) to 1.65 eV (CGS) and are also efficient absorbers across the entire solar spectrum. The absorption coefficient for CIGS is also about 105/cm. Among the thin film solar technologies, CIGS has demonstrated the best lab cell efficiency (over 20%) and the best large area module efficiency (>15%).
A class of PV absorber films of special interest is formed as CIGS-type IB-IIIA-VIA multinary chalcogenide compounds from Groups IB, IIIA, and VIA of the periodic table. Group IB includes Cu, Ag, and Au. Group IIIA includes B, Al, Ga, In, and TI. Group VIA includes O, S, Se, Te, and Po. Additionally, the IB-IIIA-VIA materials can be doped with dopants from Groups VIII, IIB, IVA, VA, and VIIA of the periodic table. Group VIII includes Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, and Pt. Group IIB includes Zn, Cd, and Hg. Group IVA includes C, Si, Ge, Sn, and Pb. Group VA includes N, P, As, Sb, and Bi. Group VIIA includes F, Cl, Br, I, and At. Other potential absorber materials of interest include kesterites like CZTS, cuprous oxide, iron sulfide, tungsten sulfide, calcium nitride, zinc phosphide, barium silicide, etc.
TFPV devices can be fabricated at the cell level or the panel level, thus further decreasing the manufacturing costs. As used herein, the cell level is understood to mean an individual unit that can be combined with other units to form a module. The cells may be rigid or flexible. As used herein, the panel level is understood to mean a large TFPV structure that is not composed of smaller units. Generally, the panels are similar in size to the aforementioned modules. For economy of language, the phrase "TFPV device" will be understood to refer to either a solar cell or a panel without distinction. Furthermore, TFPV devices may be fabricated on inexpensive substrates such as glass, plastics, and thin sheets of metal. Examples of suitable substrates comprise float glass, low-iron glass, borosilicate glass, flexible glass, flexible ceramics, specialty glass for high temperature processing, stainless steel, carbon steel, aluminum, cladded foils, copper, polyimide, plastics, etc. Furthermore, the substrates may be processed in many configurations such as single substrate processing, multiple substrate batch processing, in-line continuous processing, roll-to-roll processing, etc.
The increasing demand for environmentally friendly, sustainable and renewable energy sources is driving the development of large area, thin film photovoltaic devices. With a long-term goal of providing a significant percentage of global energy demand, there is a concomitant need for Earth-abundant, high conversion efficiency materials for use in photovoltaic devices. A number of Earth abundant, direct-bandgap semiconductor materials now seem to show evidence of the potential for both high efficiency and low cost in Very Large Scale (VLS) production (e.g. greater than 100 gigawatt (GW)), yet their development and characterization remains difficult because of the complexity of the materials systems involved.
Among the TFPV technologies, CIGS and CdTe are the two that have reached volume production with greater than 11% stabilized module efficiencies. However, the supply of In, Ga and Te may impact annual production of CIGS and CdTe solar panels. Moreover, price increases and supply constraints in Ga and In could result from the aggregate demand for these materials used in flat panel displays (FPD) and light-emitting diodes (LED) along with CIGS TFPV. Also, there are concerns about the toxicity of Cd throughout the lifecycle of the CdTe TFPV solar modules. Efforts to develop devices that leverage manufacturing and R&D infrastructure related to these TFPV technologies but using more widely available and more environmentally friendly materials should be considered a top priority for research. The knowledge and infrastructure developed around CdTe and CIGS TFPV technologies can be leveraged to allow faster adoption of new TFPV materials systems.
The development of TFPV devices exploiting Earth abundant materials represents a daunting challenge in terms of the time-to-commercialization. That same development also suggests an enticing opportunity for breakthrough discoveries. A quaternary system such as CIGS requires management of multiple kinetic pathways, thermodynamic phase equilibrium considerations, defect chemistries, and interfacial control. The vast phase-space to be managed includes process parameters, source material choices, compositions, and overall integration schemes. The complexity of the intrinsically-doped, self-compensating, multinary, polycrystalline, queue-time-sensitive, thin-film absorber (CIGS), and its interfaces to up-, and down-stream processing, combined with the lack of knowledge on a device level to address efficiency losses effectively, makes it a highly empirical material system. The performance of any thin-film, (opto-)electronically-active device is extremely sensitive to its interfaces. Interface engineering for electronically-active devices is highly empirical. Traditional R&D methods are ill-equipped to address such complexity, and the traditionally slow pace of R&D could limit any new material from reaching industrial relevance when having to compete with the incrementally improving performance of already established TFPV fabrication lines, and continuously decreasing panel prices for more traditional cSi PV technologies.
Due to the complexity of the material, cell structure, and manufacturing process, both the fundamental scientific understanding and large scale manufacturability are yet to be realized for TFPV devices. As the photovoltaic industry pushes to achieve grid parity, much faster and broader investigation is needed to explore the material, device, and process windows for higher efficiency and a lower cost of manufacturing process. Efficient methods for forming different types of TFPV devices that can be evaluated are necessary.
In light of the above, there is a need in the art for an economical method of creating CIGS absorber layers having a graded bandgap. A graded bandgap allows for higher efficiency CIGS solar cells.

Method of fabricating high efficiency CIGS solar cells


The invention relates to a method and data transfer arrangement for executing consecutive instructions in a client device (21) in a mobile device management server-client device environment (22, 21). The invention also relates to an instruction execution module utilized in the implementation of the method. In the procedure according to the invention, the device management server (22) forms the instructions to be executed in the client device (21) into an instruction sequence (200), which is transmitted to the client device (21). The instruction execution module in the client device breaks up the instruction sequence into command sequences and control structures. The instruction execution module executes the conditional commands belonging to the instruction sequence and specified by the control structures individually without the help of the device management server (22). After the execution of all the instructions, the client device (21) sends a message describing the success of the execution to the device management server.

Information available to people becomes easily dispersed to different devices and information systems. Part of the information available may be located in files in fixed networks on servers or personal computers, for example. On the other hand, terminal devices of various cellular networks, laptop computers or palm computers contain information, files and programs that are important to the user. Maintaining them in a way that the latest created version of each piece of information, file or program is always the one currently in use is a challenging task.
The management of up-to-date information in prior art decentralized information networks is an important issue. This is particularly true in the management of information and software contained by various mobile devices. Such management of information and files is generally called Device Management. Device management has the following characteristic features, among others: It enables one terminal device or server to remote control at least one other device. It also enables a program or a part thereof in a terminal device to be complemented by new information or parts of a program, which are located in another device. In addition, the validity of the licenses, or rights of use, of software is also managed by it. Device management may also comprise matters related to the management of rights (Digital Right Management).
Open Mobile Alliance (OMA) has published specifications, which concern the updating and maintenance of software in mobile devices. Some possible ways of implementing data transfer and up-to-date file maintenance of mobile devices are described in the specifications OMA DM (Device Management) and OMA DS (Data Synchronization). These specifications describe the SyncML (Synchronization Markup Language) protocol and how it is utilized.
FIG. 1 is an exemplary signal chart of the prior art operation in a server-client device environment according to the OMA standard. The transfer of information and commands between the client device 11 and the device management server 12 requires a large amount of data transfer between them. In the description below, the device management server is often also referred to by the general name server. The performance of a procedure in a client device may require the execution of a number of separate commands in a certain order. The server 12 has the responsibility for the execution of the commands, the client device 11 only implements the commands it has received one by time and reports the result to the server which gave the commands. The commands have originally been specified in a user application not shown in FIG. 1, which delivers the commands to the device management server for execution.
The conversation between the device management server 12 and the client device 11 can be like the following, for example. The conversation is started by the client, which may be, for example, the physical user of the client device 11 or the server 12 or some application program being executed in the server or client device or some third device not shown in FIG. 1. In the example of FIG. 1, the exchange of commands and messages between the device management server 12 and the client device 11 is started by the client's action. After this, the server 12 sends the first command, Ref. 13, to the client device 11 for execution. After the execution, the client device 11 sends information, Ref. 14, of the result of the operation back to the server 12 which sent the command. If the first command has been executed, the server 12 sends the next command, Ref. 15, to the client device 11. The client device executes the second command it has received and sends information of the execution of the second command back to the server. In any case, the server 12 has to check every reply message it has received before it can proceed to the execution of the next command in the instruction sequence. The reply message received from the client device 11 may also result in that the server must make a decision on which command is sent to the client device next.
The server 12 can also report to the requester of the instruction sequence, the above mentioned client, after each command executed.
The exchange of messages lasts until the server 12 sends the last command belonging to the instruction sequence to the client device 11, Ref. 18. The execution information of the command is returned by a message 19 to the server 12. If the message indicates that the execution of the last command was also successful, the message exchange between the server 12 and the client device 11 is stopped.
A central problem in wireless data transfer is the limited data transfer channel used. The prior art conversation between the server 12 and the client device 11 for executing the instruction sequence consumes the limited data transfer resources of the wireless system unnecessarily.

Method and device arrangement for managing a client/server environment


An electric potential sensor, having: a power source including a first output terminal having a first electric potential, a second output terminal having a second electric potential; a first and a second potential dividing elements connected in series between the first output terminal and the second output terminal; a ground node connected to a mutual connection node of the first potential dividing element and the second potential dividing element; a first resistance element connected between the ground node and an output node; a second resistance element connected between the output node and a detection node; a transistor connected between the first output terminal and the detection node; a pickup device for controlling a base current or a gate voltage of said transistor such that an electric potential of the detection node is equal to an electric potential of a measuring object; and a third resistance element connected between said detection node and the second output terminal.

1. Field of the Invention
The present invention relates to an electric potential sensor, and more particularly, to a feedback type electric potential sensor which measures the electric potential of an object by causing the electric potential of the sensor to be equal to the electric potential of the object.
2. Description of the Related Art
Recently, many devices (for example a PPC copying machine or a laser printer, an electrostatic dust remover) utilize static electricity. In such devices, a sensor for measuring electric potential at a charged part is essential in order that the electric potential at the charged part can be maintained at a desired value.
FIG. 4 is a schematic diagram showing an example of such an electric potential sensor. This sensor detects an electric potential Vt of an object OBJ in non-contact manner. The sensor includes a pickup device Pu which calculates the difference between the electric potential Vt of the object OBJ and an electric potential Vdet at a detection node DET and controls the base current IB of transistor Tr so that the difference between the electric potential at the detection node DET and the electric potential Vt of the object OBJ becomes 0. The electric potential Vdet at the detection node DET is divided by resistances Ra and Rb (which are situated between the detection node DET and ground GND) and is output at output node OUT. This output is indicative of the electric potential of the measuring object OBJ is to be measured.
There are several drawbacks to the prior art system. Because one side of the power source HV is grounded, only either a positive electric potential or, alternatively, a negative potential can be measured. Further, due to the influence of the leakage current of the transistor Tr, and the like, it is difficult to accurately measure a 0 V electric potential which may be a threshold value in a measuring range of the sensor. For example, in a sensor used to measure a positive electric potential, a 0 V electric potential and negative electric potentials cannot be distinguished, etc.
To overcome these problems, there has been proposed an electric potential sensor shown in FIG. 5 which can measure both positive and negative electric potentials. In this sensor, two power sources HV1 and HV2, and two transistors Tr1 and Tr2, are provided. The mutual connection node of the power sources HV1 and HV2 is grounded, and resistances Rc and Rd are provided between grounded GRD and the detection node DET. As a result, both positive and negative electric potentials can be measured, and 0 electric potential can be accurately measured. However, the structure of this sensor is complex and its cost is high.