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    A method of making a transistor device and a device so made
    12.
    发明专利
    A method of making a transistor device and a device so made 未知

    公开(公告)号：GB1087821A

    公开(公告)日：1967-10-18

    申请号：GB4962064

    申请日：1964-12-07

    Applicant: IBM

    Inventor： HAERING RUDOLPH ROLAND ,  MIKSIC MARK GEORGE ,  PENNEBAKER WILLIAM BOONE

    IPC: H01L21/203 ,  H01L27/00 ,  H01L27/088 ,  H01L29/00 ,  H01L29/78 ,  H01L29/786

    Abstract: The modulation efficiency of a T.F.T. is made high by depositing the semi-conductor material in such a way as to obtain the lowest residual carrier density consistent with the absence of unfilled trap levels. The presence of such unfilled levels would lead to reduced mobility because of their large scattering cross-section. To reduce the residual carrier density the semi-conductor may be evaporated in an atmosphere containing a material which compensates for vacancies of that constituent of the semi-conductor material which is of higher vapour pressure. Alternatively a suitable dopant may be evaporated simultaneously with the evaporation of the semi-conductor. To compensate for anion vacancies in cadmium sulphide and lead sulphide the atmosphere during evaporation may contain oxygen, sulphur or selenium, or a material supplying divalent anions which will substitutionally replace S". Acceptor impurities which may be introduced into n-type cadmium sulphide or lead sulphide are Group Ib elements such as copper and gold. Group III elements may be introduced as donors into p-type cadmium sulphide and group Va elements may be introduced as donors into p-type lead sulphide. The process may be carried out by sputtering or evaporation. The manufacture is described of a transistor having a glass substrate bearing gold electrodes, cadmium sulphide semi-conductor, and silicon monoxide dielectric. Calcium fluoride is an alternative dielectric. An evaporation apparatus is comprehensively described. The pumped chamber is connected to an oxygen supply (to compensate for S" vacancies). Separate Drumheller evaporation crucibles are provided for cadmium sulphide, gold, silicon monoxide, and for an impurity material. Each of the crucibles has its own heater and associated controller and has its own thermoelectric thermometer. A sector-shaped masking plate contains the four apertures needed respectively for the formation of the source and drain electrodes, the semi-conductor layer, the insulating dielectric layer, and the gate electrode. The plate can be rotated between the crucibles and the glass substrate to select the desired mask. While the source and drain electrodes are deposited the masking plate is held in a raised position against the substrate so that the gap between the source and drain electrodes is accurately defined. For the deposition of the other component the masking plate is held in a lower position. In this lower position the plate may be rotated so that probes fitted to one of its edges may be swept across the semi-conductor layer at intervals so that the resistivity of the layer may be monitored.

    14.
    发明专利
    未知

    公开(公告)号：DE3581388D1

    公开(公告)日：1991-02-21

    申请号：DE3581388

    申请日：1985-11-12

    Applicant: IBM

    Inventor： PENNEBAKER WILLIAM BOONE

    IPC: H04N1/40 ,  G06K9/38 ,  G06T1/00 ,  G06T5/40 ,  G09G5/36 ,  H04N1/407 ,  H04N1/41

    Abstract: A system is described for thresholding graphics images to reduce the information content for transmission and reproduction and which uses a particular image data thresholding technique that may be used to obtain display images with a number of intensity levels. Firstly, an histogram of the image to be encoded is generated and analyzed to determine essential parameters. In particular, the background colour of the image is determined by summing the histogram elements to find the median (B) of the distribution, that is, the point at which the half sum of total pixels is reached. The extrema (A. G) of the histogram are calculated and the skew is determined from the position of the median (B) with respect thereto. If the difference between the median (B) and the black extreme (G) is less than half the difference between the median (B) and the white extreme (A) then the background of the image is deemed to be black, otherwise, the image will be defined as having a white background. After the background colour is determined, the width of the background is determined from the difference between the median (B) and the background colour extreme (A), and the edge between the background and foreground regions, is defined as being at a distance one-half the background width from the median (B) in the direction of the foreground colour extreme (G). A sequence of threshold levels (D, E, F) may then be determined using this edge (C) as a base, by setting them at points disposed at fractionally different distances between the edge (C) and the foreground colour extreme (G). Preferably the levels are set at points 1/8, 1/4 and 1/2 the defined distance or at 3/16, 3/8 and 3/4. The selected points will respectively define the threshold levels such as between white/gray-white, gray-white/gray-black, and gray-black/black. Thus, the resulting image may then, after encosing and transmission, be decoded and displayed on a suitable teleconferencing system or fascimile machine with four intensity levels.

    15.
    发明专利
    未知

    公开(公告)号：DE3381868D1

    公开(公告)日：1990-10-11

    申请号：DE3381868

    申请日：1983-11-22

    Applicant: IBM

    Inventor： ANASTASSIOU DIMITRIS ,  PENNEBAKER WILLIAM BOONE

    IPC: H04N5/16 ,  G06T5/20 ,  H04N1/403 ,  H04N1/40

    Abstract: Nonlinear shading correction of an image to improve readability and data compression is effected by means for generating a histogram of distribution of gray scale intensity levels, means for calculating from the histogram first, second and third gray scale intensity values, means for determining image polarity, means for determining an acceptable range of background gray scale variation, means for sampling gray scale intensity values in a region around a current pel, means for calculating a correction value for the current pel by comparing the gray scale value of the current pel with the range of background gray scale variation, means for setting the correction value to a predetermined constant if the gray scale value of the current pel is outside the range of a acceptable background variation, and means for correcting the current pel gray scale value by subtracting therefrom the correction value to achieve a shading corrected value for the current pel.

    NONLINEAR FILTERING OF GRAY SCALE VIDEO IMAGES
    16.
    发明专利
    NONLINEAR FILTERING OF GRAY SCALE VIDEO IMAGES 未知

    公开(公告)号：DE3377449D1

    公开(公告)日：1988-08-25

    申请号：DE3377449

    申请日：1983-11-22

    Applicant: IBM

    Inventor： ANASTASSIOU DIMITRIS ,  PENNEBAKER WILLIAM BOONE

    IPC: G06T3/40 ,  H04N5/14 ,  H04N5/21

    Abstract: Filtering noise from digital video images is achieved by means for determining first difference values between intensity values of current pel and one or more preceding pels, means for determining second difference values between intensity values of the current pel and one or more succeeding pels, means for limiting any of the first and second difference values that exceed a predetermined limit value, and means for generating a filtered value for the current pel by adding the intensity value of the pel to a scale summation of the limited first and second difference values.

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