Cathode-ray Tube Patents (Class 348/805)
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Patent number: 8289456Abstract: Disclosed is an image correction method of correcting an image including a number of horizontal image scan lines each corresponding to a number of pieces of image data. The method includes the following steps: segmenting each of the horizontal image scan lines into a plurality of segments according to a plurality of nodes, each of the segments having an original segment length; looking up a table to generate at least one correction parameter according to a selection signal; generating a gain value according to a control signal; correcting the original segment length to generate an adjusted segment length according to the gain value and the correction parameter; and altering positions of the plurality of nodes to correct the image according to the adjusted segment length.Type: GrantFiled: June 5, 2008Date of Patent: October 16, 2012Assignee: Mstar Semiconductor, Inc.Inventors: Ren-Kuan Liang, Meng-Che Tsai, Yu-Chieh Hung
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Patent number: 7920214Abstract: A method for formation of projection systems color video-images comprises: preliminary programmed processing of video-signals, dividing them into three primary colors components, and generating frame- and line-synchronizing pulses for CRT raster, provided by processing means; formation of three primary color images adjacently positioned on a screen of a single projection type one-beam CRT, the screen of which is divided into three rectangular areas for red, green and blue images wherein each area is coated by a red, green, or blue color phosphor layer respectively, and each image of a primary color is located on the corresponding phosphor layer of its color; superimposing the images to form a combined color image by optical means; displaying the combined color image on a common projection screen.Type: GrantFiled: January 16, 2007Date of Patent: April 5, 2011Inventor: Arayik Danghyan
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Publication number: 20090262263Abstract: A transposed or vertical scan CRT that is compatible with multiple different input video signals so as to allow the same to operate according to different video signal transmission standards. A frame rate converter is positioned to receive incoming HDTV signals from any source. The incoming signals can be at any frame rate, for example, 24 Hz, 25 Hz, 50 Hz, 60 Hz, 72 Hz and 75 Hz. The addition of a frame rate converter provides a single vertical/horizontal display scan rate combination for all incoming signal rates.Type: ApplicationFiled: June 5, 2006Publication date: October 22, 2009Inventor: Richard Hugh Miller
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Publication number: 20090079858Abstract: Disclosed is a scanning image display device for displaying an image on a plurality of display screens. The image display device includes a light source, a scanner for two-dimensionally scanning with light from the light source, and a controller which is electrically connected with the light source and the scanner. The controller controls the light source and the scanner to form an image on the surfaces to be scanned. The scanner is configured to be capable of scanning the independent plurality of scanning surfaces with the light from the light source.Type: ApplicationFiled: December 1, 2008Publication date: March 26, 2009Applicant: CANON KABUSHIKI KAISHAInventor: Akira YAMAMOTO
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Patent number: 7499111Abstract: The system provides a projection-type video display device with high image quality and high reliability. The system improves color purity by cutting the yellow component from red and green, enhances the optical energy balance of the three colors by providing a reflection-type attenuation filter for reflecting light in the green optical path. The system also improves contrast characteristics by providing an optical phase difference compensator in the green optical path and increases durability of a video display element by arranging two optical parts having ultraviolet reflection coating in the blue optical path. Also an ultraviolet absorption filter for the incidence side of a blue liquid crystal panel is described.Type: GrantFiled: May 10, 2004Date of Patent: March 3, 2009Assignee: Hitachi, Ltd.Inventors: Koji Hirata, Masahiko Yatsu
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Publication number: 20090009428Abstract: A method and apparatus for controlling brightness, color and contrast in CRT monitors used in information handling systems. In accordance with the present invention, a viewing area on a CRT monitor is enhanced by applying appropriate signals directly to the grids in the CRT. In one embodiment of the present invention, appropriate voltage signals are applied to the G1 grid of the CRT. Parameter data is provided to the CRT using a DDC2/CI data channel, with the parameter data being based on the VESA MCCS command set. Utilizing the method and apparatus of the present invention, it is possible to achieve significantly greater brightness, color and contrast control in enhanced viewing areas displayed on a CRT monitor used in an information handling system.Type: ApplicationFiled: September 16, 2008Publication date: January 8, 2009Inventor: Joseph Edgar Goodart
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Patent number: 7187414Abstract: Disclosed is a circuit for stabilizing a high tension voltage of a CRT and a method thereof. A feedback unit receives a cutoff voltage from the CRT. A compensating unit calculates a variation quantity of the cutoff voltage on the basis of the cutoff voltage from the feedback unit. The variation quantity of the cutoff voltage is compared with a high tension voltage compensation data stored in a storing unit according to the variation quantity of the cutoff voltage. Accordingly, the circuit for stabilizing the high tension voltage of the CRT and the method thereof can overcome inaccuracy of the high tension voltage compensation due to delay, and cut down the production cost by removing an ABL circuit and a high tension voltage compensating capacitor. Since the ABL circuit is not used, it is also possible to perform partial compensation according to an alternating current variation quantity.Type: GrantFiled: September 12, 2002Date of Patent: March 6, 2007Assignee: Samsung Electronics Co., Ltd.Inventor: Chang-joo Jung
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Patent number: 7057336Abstract: An electron-emitting device comprises a pair of electrodes and an electroconductive film arranged between the electrodes and including an electron-emitting region carrying a graphite film. The graphite film shows, in a Raman spectroscopic analysis using a laser light source with a wavelength of 514.5 nm and a spot diameter of 1 ?m, peaks of scattered light, of which 1) a peak (P2) located in the vicinity of 1,580 cm?1 is greater than a peak (P1) located in the vicinity of 1,335 cm?1 or 2) the half-width of a peak (P1) located in the vicinity of 1,335 cm?1 is not greater than 150 cm?1.Type: GrantFiled: March 20, 2003Date of Patent: June 6, 2006Assignee: Canon Kabushiki KaishaInventors: Fumio Kishi, Masato Yamanobe, Takeo Tsukamoto, Toshikazu Ohnishi, Keisuke Yamamoto, Sotomitsu Ikeda, Yasuhiro Hamamoto, Kazuya Miyazaki
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Patent number: 7023149Abstract: The invention concerns a scanning circuit, comprising a power supply providing a negative voltage on a first terminal (Tdown), an intermediate voltage on a second terminal (Gnd) and a positive voltage on a terminal of a switch (S), the other terminal of the switch being connected to a third terminal (Tup), a control circuit (6) supplied by connections to the second and third terminals, a differential amplifier receiving a positive and a negative input signal provided by the control circuit, a power amplifier controlled by the differential amplifier, both amplifiers being supplied by connections to the first and third terminals, a deflection coil (Ly) connected between the output of the power amplifier and the second terminal, biasing means setting, when the switch is open, the output of the differential amplifier so that the possible current paths through the power amplifier between the deflection coil and the first terminal are cut.Type: GrantFiled: March 30, 2004Date of Patent: April 4, 2006Assignee: STMicroelectronics S.A.Inventor: Jean-Michel Moreau
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Patent number: 6822699Abstract: A main picture is displayed in monochrome in a main picture display area by emission of a first phosphor layer formed of a white emission phosphor. A second phosphor layer formed of a phosphor different from the first phosphor layer is provided in a region different from the first phosphor layer. Icons are displayed in the icon display area in a color different from the main picture by emission of the second phosphor layer.Type: GrantFiled: February 8, 2001Date of Patent: November 23, 2004Assignee: Sony CorporationInventor: Koichi Furui
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Publication number: 20040212744Abstract: To cushion an impact acting on bosses to prevent the same from being transmitted to a cabinet body, a television set having reinforced boss structure of a cabinet for fixation of a cathode ray tube has ribs formed with notches, with thin-walled portions, with curved portions, or gaps are formed between ribs and inner wall surfaces of the cabinet so that an impact acting on the bosses is absorbed.Type: ApplicationFiled: April 23, 2004Publication date: October 28, 2004Inventor: Takayuki Saitoh
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Patent number: 6690339Abstract: A method and a circuit arrangement for controlling the operating point of a cathode ray tube (3) for use in image technology applications. A video signal (1) is supplied to both the tube (3) and to a cathode ray tube model (2), which the model (2) uses to emulate a beam current. From the emulated beam current and a measured beam current, a characteristic quantity for adjusting the operating point is determined.Type: GrantFiled: June 7, 2001Date of Patent: February 10, 2004Assignee: Siemens AktiengesellschaftInventors: Klaus Burkhardt, Uwe Nagel, Erich Schaefer, Hartmut Schulz
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Patent number: 6674231Abstract: A panel for a color cathode ray tube includes an opening portion provided with a seal end surface to which a funnel is sealed through a frit glass. The seal end surface of the opening portion is a rough surface comprising a large number of streak-shape ridges and troughs in which minute recesses and protrusions range in a circumference direction of the seal end surface.Type: GrantFiled: April 25, 2002Date of Patent: January 6, 2004Assignee: Nippon Electric Glass Co., Ltd.Inventor: Michiharu Eta
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Patent number: 6664747Abstract: A horizontal dynamic focus regulation circuit, which induces a horizontal dynamic focus waveform voltage by a horizontal deflection circuit generating a different frequency according to a display mode of a display apparatus, comprising a microcomputer outputting a plurality of control signals; a plurality of switching parts corresponding to the plurality of control signals outputted from the microcomputer, respectively; a plurality of S-regulation capacitors connecting with the plurality of switching parts in series, respectively; an auxiliary capacitor provided on a line diverged from a line connecting each switching part with each S-regulation capacitor, and being respectively connected with the S-regulation capacitor in parallel and series according to switching on and off of the switching part. With this configuration, the dynamic focus regulation circuit supplies a uniform parabolic waveform voltage regardless of variation of a horizontal frequency in a display mode.Type: GrantFiled: May 6, 2002Date of Patent: December 16, 2003Assignee: Samsung Electronics Co., Ltd.Inventor: Ho-Woong Kang
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Patent number: 6590620Abstract: In a CRT display apparatus, a horizontal distortion correction apparatus is provided for correcting horizontal distortion of an image by applying a residual phase to control the phase of a horizontal deflection current. The horizontal distortion correction apparatus corrects horizontal distortion of an image caused by an assembly error of the CRT display apparatus for displaying an image by scanning a video signal, based on a horizontal synchronizing signal included in the video signal. The horizontal distortion correction apparatus includes a PLL supplying the horizontal deflection current to a video signal controller for displaying an image on the CRT. A distortion-correcting waveform generator is operated by the user, applying a wave signal having a desired waveform to the PLL to provide a residual phase for the horizontal deflection current to control the phase thereof. As a result, the image without horizontal distortion is displayed on the CRT display apparatus.Type: GrantFiled: January 21, 2000Date of Patent: July 8, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Haruyasu Hirakawa
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Patent number: 6570625Abstract: Anode voltages A′ and B′ corresponding to video signals A and B are switched by a first switch and supplied to an anode. Cut-off voltages A and B corresponding to the video signals A and B are switched by a second switch and added to a video signal by an adder. A resultant signal is supplied to a cathode. In a CRT, the luminance rises in association with the step-down of the cut-off voltage and the step-up of the anode voltage and the resolution rises in association with the step-up of the cut-off voltage and the step-up of the anode voltage. The first and second switches are switched in accordance with the format of the input video signal respectively, thereby properly selecting the anode voltage which is applied to the CRT and the cut-off voltage. The video image can be displayed by the CRT at the luminance and resolution according to the video signal without changing a driving voltage.Type: GrantFiled: January 7, 1999Date of Patent: May 27, 2003Assignee: Sony CorporationInventors: Kazuto Kuyama, Manabu Suzuki
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Patent number: 6563552Abstract: Provided are an image correcting method and device capable of reducing power consumption necessary for correcting an image for a long-time use and a cathode ray tube display unit. A microcomputer 2 calculates a value of a correction current in such a manner that the correction current is more decreased monotonously as a time passes after a cathode ray tube is turned on. Drivers 3 to 7 and 22 generate and output the correction current according to the value of the correction current calculated by the microcomputer 2. A correcting device C is provided in the cathode ray tube and serves to correct an image displayed on the cathode ray tube on receipt of the correction currents from the drivers 3 to 7 and 22.Type: GrantFiled: October 27, 1999Date of Patent: May 13, 2003Assignee: NEC-Mitsubishi Electric Visual Systems CorporationInventor: Takeshi Chujo
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Patent number: 6552752Abstract: When an STB is powered off when it is not used (when it is changed to the sleep mode) for the purpose of power-saving, a difference in a subtracter immediately therebefore is held by a control circuit and an oscillation circuit is controlled on the basis of the difference, thereby performing reserved processing at a correct time even when the STB is in the sleep mode.Type: GrantFiled: May 17, 2000Date of Patent: April 22, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toshiaki Tsuji, Toshiroh Nishio
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Publication number: 20030035076Abstract: A display apparatus has a cathode ray tube bulb which includes a panel displaying a picture thereon, a funnel combined with the panel, and a neck connected to the funnel. The display apparatus further comprises an electron gun unit which includes an electron gun main body inserted into the neck and a boss part protruding from the neck at a rear part of the electron gun main body and having a plurality of pins disposed therearound, and a video unit which includes a video PCB disposed parallel to the axis of the neck and a boss holder vertically provided on the video PCB and combined with the boss part so as to transmit a video signal from the video PCB to the electron gun unit. With this configuration, space for installation of the video PCB is minimized, and the video unit is not easily separated from an electron gun unit.Type: ApplicationFiled: November 30, 2001Publication date: February 20, 2003Inventors: Kwey-Hyun Kim, You-Sub Lee
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Patent number: 6509936Abstract: A method and projection television system for projecting images having a plurality of color components, includes a device for filtering a first color component signal from a composite signal to provide a filtered first color component signal. A defocusing mechanism defocuses the first color component signal based on the filtered first color component signal. A gain adjustment device adjusts a gain of at least one other of a plurality of color component signals of the composite signal. An amount of defocusing performed by the defocusing mechanism and a gain adjustment by the gain adjustment device are dependent on a content of the composite signal. In another aspect of the invention, a spot wobble scheme may be employed alone in a static defocussing system, without dependence upon the video signal content.Type: GrantFiled: November 1, 1996Date of Patent: January 21, 2003Assignee: Koninklijke Philips Electronics N.V.Inventor: Matthew Scott Brennesholtz
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Patent number: 6506317Abstract: A cooling medium and a cooling device for optical equipment using the same, which cooling medium has a refractive index in a specific range, hardly causes the problem to dissolve or swell plastic lens and other component parts, and is flame retardant. The cooling medium comprises a cyclic aliphatic hydrocarbon having at least one cross linkage and has a flash point of 120° C. or above and a melting point of −20° C. or below. The space between a pair of transparent optical members of a cooling device for optical equipment, is filled with the cooling medium.Type: GrantFiled: May 26, 2000Date of Patent: January 14, 2003Assignees: Nippon Petrochemicals Company, Limited, San-Petrochemicals Co., Ltd.Inventors: Hiroyuki Hoshino, Takashi Kiyota
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Patent number: 6493040Abstract: A video display deflection circuit includes a source of a video signal for displaying picture information contained in the video signal in a screen of a cathode ray tube. The video signal provides selectively on-screen-display information and non-on-screen-display information. A source of a first control signal has a first value, when the video signal provides on-screen-display information and a second value, when said video signal provides non-on-screen-display information. A waveform generator is responsive to the first control signal for generating a second signal at a frequency that is related to a deflection frequency having a first waveform, when the video signal provides on-screen-display information, and a second waveform, that is different from the first waveform, when the video signal provides non-on-screen-display information.Type: GrantFiled: May 26, 1999Date of Patent: December 10, 2002Assignee: Thomson Licensing S.A.Inventor: Rick Wayne Miller
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Patent number: 6489994Abstract: A method and device utilizes a brightness control circuit for protecting a cathode ray tube in an image displaying device. The displaying device has an image signal amplifier, a cathode ray tube, and a brightness control circuit. The cathode ray tube has a screen, an electron gun, and an anode for collecting an electron beam emitted onto the screen to produce an anode current. The brightness control circuit is electrically connected to a control end of the image signal amplifier for controlling the amplification magnitude of the image signal amplifier and electrically connected with the anode of the cathode ray tube via a flyback transformer, wherein when the incoming image signals make the image picture shown on the screen too bright, the anode current of the anode will be increased accordingly, and the brightness control circuit will reduce the amplification magnitude of the image signal amplifier at the same time according to the increase of the anode current so as to reduce the anode current.Type: GrantFiled: March 27, 2000Date of Patent: December 3, 2002Assignee: Benq CorporationInventor: Hsieh Chang-Fa
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Patent number: 6483557Abstract: Unintentional emissions are controlled responsive to the spectral content of the display signal. A video display apparatus comprises a cathode ray tube responsive to a video signal. A processor controls a bandwidth of the video signal coupled to the cathode ray tube in response to an emission control signal. A generating device is coupled to the processor for generating the emission control signal responsive to a component of the video signal.Type: GrantFiled: November 5, 1999Date of Patent: November 19, 2002Assignee: Thomson Licensing SAInventors: Jeffrey Owen Allender, Dal Frank Griepentrog, Brian Jonathan Cromarty
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Patent number: 6384876Abstract: A video projector is arranged with three color CRTs vertically aligned with respect to a forwardly located projection surface. The projection surface is in a room having opposite side walls on either side of said projection surface. The video projector is positioned closely adjacent either of said side walls, thus leaving the ceiling and floor areas of the room unobstructed. The arrangement facilitates non intrusive use of a video projector in a home environment.Type: GrantFiled: December 9, 1994Date of Patent: May 7, 2002Assignee: Zenith Electronics CorporationInventor: Tom L. Sorensen
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Publication number: 20020051097Abstract: The invention relates to apparatus for measuring color, the apparatus comprising: an acquisition system including a video camera and processing means organized to respond to the signals delivered by the camera to determine the tristimulus values of the color of the object in a reference calorimetric system by using a transfer matrix to transform the calorimetric system associated with said acquisition system into the reference calorimetric system, and to determine a correction function &Ggr; to correct the non-linearities of said acquisition system.Type: ApplicationFiled: October 10, 2001Publication date: May 2, 2002Applicant: L'OREALInventors: Laurence Caisey-Bluteau, Johan Aubert
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Patent number: 6377319Abstract: A projection television set having a screen and three projection units each capable of projecting a monochromatic image onto the screen. The projection units each having a cathode ray tube (CRT) optically coupled to a projection lens, which includes both a C-lens and a compound lens. A spacer preferably having three optical passageways is coupled to and between the CRTs and projection lenses. Each CRT is coupled to the spacer via a holder having a housing adapted to capture the CRT and two mounting brackets, each preferably adapted to distribute a spring load to at least two points on the housing.Type: GrantFiled: May 15, 2000Date of Patent: April 23, 2002Inventor: Masayoshi Shinobu
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Patent number: 6369851Abstract: A method and apparatus for displaying a video signal is described. A video signal is received representing an image having a first aspect ratio, with the image having a top and bottom edge. An edge modification signal is generated. The image is displayed on a display having a second aspect ratio with the top and bottom edge modified in accordance with the edge modification signal. Accordingly, burn lines are minimized through use of the edge modification signal to reduce brightness levels at the top and bottom edge of the image.Type: GrantFiled: September 24, 1999Date of Patent: April 9, 2002Assignees: Sony Corporation, Sony Electronics Inc.Inventors: Thomas Adreon Marflak, Hirohide Kiga, David Scott Arnold
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Patent number: 6262524Abstract: A color cathode ray tube, and an electron gun of the same, having a superior focus characteristic. An electron gun is provided, emitting electron beams through a Gla electrode, G2a electrode, GMAa electrode, GMBa electrode, and G3 electrode. The electrons from a quadrupole and main focus lenses. Three cathodes 12B, 12B, etc. for discharging R, G, and B electron beams are provided in parallel with each other. A cup-shaped conductive member 60 is affixed to the GMBa electrode at the downstream side of the quadrupole lens formed by the GMAa electrode and GMBa electrode. The two side electron beams are oriented toward the center electron beam by the potential difference between the cup-shaped conductive member 60 and G3 electrode.Type: GrantFiled: April 17, 1998Date of Patent: July 17, 2001Assignee: Sony CorporationInventor: Yoshihiro Ouchi
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Patent number: 6256074Abstract: A video imaging apparatus includes a source of a blanking signal that is indicative when a blanking interval occurs in a video signal. A delay circuit including a horizontal line counter is responsive to the blanking signal and to a signal at the horizontal rate for delaying the blanking signal by a multiple number of horizontal periods to generate a delayed signal. A dynamic focus voltage generator includes a switch responsive to the delayed signal for applying a dynamic focus voltage to a focus electrode, when the switch is at a first state, and for disabling the application of the dynamic focus voltage, when the switch is at a second state. An end time of the interval, during which the dynamic focus voltage is disabled, is determined in accordance with an output signal of the counter.Type: GrantFiled: August 7, 1998Date of Patent: July 3, 2001Assignee: Thomson Licensing S.A.Inventors: James Albert Wilber, Jeffery Basil Lendaro
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Publication number: 20010005237Abstract: 1. A display device is manufactured having a display with an auxiliary plate. The display window (3) and the auxiliary plate (15) are oriented at an angle of tilt &agr;1, preferably substantially vertically, the volume in between the display window and auxiliary plate is filed up to a selected level height (h) with uncured resin, a seal (17) and an opening (18) being provided at or near the highest point. Thereafter the display window is reoriented to a more horizontal position (smaller angle of tilt &agr;2) the auxiliary plate being positioned on top of the display window inducing a flow v of curable material (16) towards the opening (18), and when the resin has reached the opening the resin near the opening is plugged, where after the angle of tilt is further reduced and the resin is fully cured. FIG.Type: ApplicationFiled: December 4, 2000Publication date: June 28, 2001Inventor: Gosse Charles De Vries
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Patent number: 6211908Abstract: Supplementary grid blanking and spot burn protection are provided in a receiver/monitor (10) by a grid bias control circuit (50) including a blanking signal generator (60) that produces a blanking output signal (S1) devoid of any picture representative component whenever a vertical blanking signal (VB) or a horizontal blanking signal (HB) is present. A capacitor (C1) strips DC from the blanking signal and the resultant signal (S2) is applied to a modulation input (84) of a grid bias generator to produce an output grid bias reference voltage (Vr) modulated by the AC component of the blanking signal. The reference voltage (Vr) is coupled via a spot burn protection circuit (100) and a grid coupling circuit (120) to the control grids of three projection kinescopes (16, 18, 20).Type: GrantFiled: May 27, 1999Date of Patent: April 3, 2001Assignee: Thomson multimedia Licensing S.A.Inventor: Dal Frank Griepentrog
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Patent number: 6169587Abstract: A circuitry for attaining a fixed raster vertical scan size of a video display apparatus is proposed. The video display apparatus comprises a flyback transformer (FBT) which includes a primary winding and a secondary winding. The secondary winding has a terminal generating a high voltage to an anode of a cathode ray tube (CRT) of the video display apparatus via an external loading. Moreover, the secondary winding has a voltage reference terminal. The raster vertical scan size adjustment circuit comprises a compensation circuit and a raster vertical scan size control circuit. The compensation circuit includes an input terminal adapted to connect the voltage reference terminal of the secondary winding for detecting voltage change at the voltage reference terminal responsive to variation of the external loading. The compensation circuit has an output terminal generating the compensated signal.Type: GrantFiled: March 31, 1997Date of Patent: January 2, 2001Assignee: Acer Peripherals Inc.Inventor: Hsieh Chang-Fa
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Patent number: 6072547Abstract: A color display device having a color display tube with a display screen, comprising an electron gun for generating three co-planar electron beams, and a deflection system which, in operation, generates deflection fields for scanning the display screen, and an element influencing the landing angle of the outermost beams, for example an element generating, in operation, a 45.degree. magnetic 4-pole field, and comprising a correction device which supplies a signal to the element influencing the landing angle, which signal is derived from the video information (for example a signal which is proportional to the strength of the instantaneous beam current) in order to remedy landing errors caused by space-charge repellence between beams.Type: GrantFiled: May 16, 1997Date of Patent: June 6, 2000Assignee: U.S. Philips CorporationInventor: Albertus A. S. Sluyterman
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Patent number: 6064434Abstract: In a beam current measurement device, including an output transistor (T1) for supplying a cathode current (Ic), a measurement output (OUTM) for supplying a measured current (Im) representing the cathode current (Ic), a first current source (Ibias1) coupled to a first main terminal of the output transistor (T1) for supplying a first current (Ibias1), and a second current source (Ibias2) coupled to a second main terminal of the output transistor (T1) for supplying a second current (Ibias2) substantially equal to the first current (Ibias1), a first cascode transistor (Ta) is coupled between the first main terminal of the output transistor (T1) and the measurement output (OUTM).Type: GrantFiled: February 3, 1997Date of Patent: May 16, 2000Assignee: U.S. Philips CorporationInventor: Pieter Van Der Zee
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Method and apparatus for reducing electromagnetic interference radiated by cathode ray tube displays
Patent number: 6020939Abstract: Electromagnetic interference ("EMI") is reduced in a CRT video display system by spreading-out the EMI-producing spectra present in the video pixel data and/or clock signals. A clock dropping circuit coupled between the display generator main oscillator and the timing generator periodically phase-modulates the timing generator clock signal such that it comprises N phases, where N.gtoreq.2. As a result, each horizontal line of video data and the horizontal synchronization signals is phase shifted. This dual-shifting effect eliminates display image distortion that would result if only the video signal were shifted. Video distortion is further minimized by deriving the horizontal and vertical synchronizing signals from a common constant clock. EMI energy associated with each clock harmonic is spread by a frequency amount .DELTA.f proportional to the rate of phase change in the clock signal, the rate of phase change exceeding half the bandwidth f.sub.m of a standard EMI measurement reference window.Type: GrantFiled: January 19, 1996Date of Patent: February 1, 2000Assignee: Sun Microsystems, Inc.Inventors: Abraham E. Rindal, Ronald H. Ih, Michele K. Law -
Patent number: 6002453Abstract: A series arrangement of a deflection coil (Lf) and a series resistor (Rs) is connected between an output of a first output amplifier (1) and an output of a second output amplifier (2) to be driven in a bridge configuration for generating a deflection current (If) through the deflection coil (Lf). Across the series resistor (Rs), a voltage is generated which corresponds to the deflection current (If). A differential amplifier (5) has a first input connected to a first end of the series resistor (Rs). A second input of the differential amplifier (5) is connected to a second end of the series resistor (Rs) via a conversion resistor (Rc). An input current (Ii) is generated through the conversion resistor (Rc). The polarity of the input current (Ii) is selected to obtain a voltage across the conversion resistor (Rc) which has an opposite polarity with respect to the voltage across the series resistor (Rs).Type: GrantFiled: September 30, 1997Date of Patent: December 14, 1999Assignee: U.S. Philips CorporationInventors: Adrianus J. M. Van Tuijl, Erik Van Der Ven
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Patent number: 5977727Abstract: An apparatus and method to dynamically shape the projected energy profile of an electron beam and the energy distribution of an electron beam of a cathode ray tube to provide a single cathode ray tube the ability to display multiple image formats of varying resolutions, brightnesses and aspect ratios. In one embodiment, the invention contemplates the introduction of a shaping lens along the path of the electron beam comprising at least three electrodes. Voltages are selectively applied to the electrodes to dynamically and selectively vary the projected energy profile of an electron beam in a plane perpendicular to the longitudinal axis of the cathode ray tube.Type: GrantFiled: May 9, 1997Date of Patent: November 2, 1999Assignee: Imaging & Sensing Technology CorporationInventor: Thomas A. Dunbar
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Patent number: 5956099Abstract: A circuit for clipping a dynamic focus voltage waveform during a horizontal retrace time is provided so as to prevent an unnecessary voltage from occurring during the retrace time. A high gain amplifier for amplifying horizontal and vertical parabolic waves is provided with an output circuit used as an emitter follower, a D.C. feedback circuit and a boot strap circuit composed of a capacitor. As a result, a display can be provided which is capable of performing a large amplitude operation without increasing power losses, realizing a satisfactory frequency response simultaneously with the amplitude operation and providing excellent focus properties over the entire screen thereof.Type: GrantFiled: November 26, 1996Date of Patent: September 21, 1999Assignee: Hitachi, Ltd.Inventor: Toshimitsu Watanabe
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Patent number: 5926211Abstract: In a method of measuring a focus of a cathode ray tube, a predetermined image is displayed at a predetermined position on the screen of the cathode-ray tube. A focussing voltage of the cathode ray tube is changed under a condition that a distance from a reference position to a predetermined position in the image is detected. A change state of the detected distance is displayed on a display. Further, an image having representation of at least a vertical-direction line and a horizontal-direction line is employed as the predetermined image. A line sensor is located so as to cross both of the vertical-direction line and the horizontal-direction line to set a predetermined position of the line sensor as the reference position.Type: GrantFiled: March 25, 1997Date of Patent: July 20, 1999Assignee: Sony CorporationInventor: Tomoyasu Nakayabu
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Patent number: 5923387Abstract: A focusing waveform (Vf) is obtained by first generating (2) two intersecting triangular waveforms of opposite phase and half the deflection frequency. Subsequently, the difference between these two triangular waveforms is multiplied by itself for generating a second-order parabolic waveform at the deflection frequency, at which the parabolic waveform has a lower side which is located at zero and is not disturbed by DC offsets. In an advantageous embodiment of the invention, which is eminently suitable for multimedia applications, the focusing waveform has the correct form and amplitude, independent of the deflection frequency.Type: GrantFiled: June 5, 1997Date of Patent: July 13, 1999Assignee: U.S. Philips CorporationInventor: Robert C. C. Van der Sanden
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Patent number: 5841487Abstract: In a circuit arrangement for direct current control of a picture display tube having a non-linear voltage/current characteristic by a precorrected picture signal, the picture signal is applied to a non-linear compensation circuit (3) which cancels the precorrection of the picture signal and controls a controlled current source (8) at the output end, whose output is coupled to the cathode (10) of the picture display tube (1), and a differentiator (13) is provided which differentiates the picture signal and controls a voltage-controlled compensation current source (12) which is coupled to the cathode (10) of the picture display tube (1) for a picture signal-dependent reversal of the charge of the parasitic input capacitance (11) of this picture display tube.Type: GrantFiled: May 13, 1996Date of Patent: November 24, 1998Assignee: U.S. Philips CorporationInventors: Matthias Peters, Christian Brun
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Patent number: 5805211Abstract: An electrostatic probe device detects signals displayed on a cathode ray tube in a non-invasive manner. Specifically, the probe device includes a probe that is spaced from a fluorescent screen of a cathode ray tube by a dielectric material and a detection circuit coupled to probe. The detection circuit produces an output signal that corresponds to an input video signal supplied to the cathode ray tube. In a preferred embodiment, the probe is located directly on a face plate of the cathode ray tube, wherein the face plate acts as the dielectric material. Voltage fluctuations detected by the probe are equalized by the detection circuit. The detection circuit may also include amplification and inverter circuits, so that the output of the detection circuit can be supplied to a monitor for viewing. The image displayed on the monitor directly corresponds to the image displayed on the cathode ray tube.Type: GrantFiled: September 15, 1995Date of Patent: September 8, 1998Inventor: Ted E. Hartson
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Patent number: 5793448Abstract: A cathode ray tube package includes a cathode ray tube assembly and a housing assembly including a deflection coil and/or at least one focus coil. The cathode ray tube assembly includes a collar (31) aligned with the electron beam, being arranged to mate with a mounting collar (41) carried on the housing assembly. The provision of the collar (31) enables the cathode ray tube assembly to be easily replaced at the end of the cathode ray tube's life within the housing assembly without the need for realignment of the coils.Type: GrantFiled: September 26, 1995Date of Patent: August 11, 1998Assignee: Brimar LimitedInventors: George David Atkinson, James Francis Nangle
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Patent number: 5627597Abstract: A television receiver is provided which includes a vertical deflection circuit which causes interlacing of an interlaced video signal having two fields each with an integral number of scan lines. The vertical deflection circuit including a jog circuit coupled to a vertical deflection yoke, which jog circuit causes a change in current through the vertical deflection yoke during reception of one of the fields. This change in current causes the fields to interlace with each other when scanned on a picture tube.Type: GrantFiled: April 23, 1996Date of Patent: May 6, 1997Assignee: Philips Electronics North America CorporationInventor: Lawrence E. Donovan
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Patent number: 5606377Abstract: The invention relates to an implosion protection band 26, 126 for a CRT having a plurality of brackets 40, 70, 140 that are disposed between the band and a sidewall 3 of the CRT 1 and detachably attached to the implosion protection band to support either a degaussing coil 9 or to facilitate mounting the CRT within a receiver.Type: GrantFiled: October 10, 1995Date of Patent: February 25, 1997Assignee: Thomson Consumer Electronics, Inc.Inventor: Harry R. Swank
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Patent number: 5557344Abstract: A multi-beam electron gun for a color cathode ray tube (CRT) includes a plurality of vertically spaced, horizontal inline beams, where each inline array of beams provides the three primary colors of red, green and blue and adjacent inline beam arrays simultaneously trace adjacent horizontal scan lines on the color CRT's display screen. The beams in each horizontal inline array of beams are focused on a common spot on the display screen, with the three beams deflected across the screen in unison. Each inline array of beams is modulated in accordance with that portion of the video image which they form allowing adjacent, vertically spaced inline arrays to write different video image information on the screen in simultaneously forming adjacent portions of the color video image. In the beam-forming region of the electron gun, a charged grid includes an array of apertures including at least upper and lower horizontally aligned apertures for passing inline arrays of beams.Type: GrantFiled: February 7, 1994Date of Patent: September 17, 1996Assignee: Chunghwa Picture Tubes, Ltd.Inventor: Hsing-Yao Chen
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Patent number: 5555032Abstract: An integrated circuit for power management adapted to be used with a monitor which comprises a signal discriminator storing two reference values therein for being put in comparison with an input signal and generating an output signal according to the comparison, a clock generator adapted to be electrically connected to an oscillating circuit generating an oscillating signal, receiving and processing said oscillating signal to provide a clock input for the integrated circuit for power management, and a decoder decoding the output signal to enable the monitor in a desired operation state. The present integrated circuit for power management can not only prolong the lifetime of a cathode-ray tube but can also economize power consumption in consideration of environmental protection and economy. In addition, the present integrated circuit is more space-saving and cost-effective than a conventional device for economizing power consumption.Type: GrantFiled: May 9, 1994Date of Patent: September 10, 1996Assignee: Weltrend Semiconductor, Inc.Inventor: Yung-Keng Kung
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Patent number: 5552663Abstract: The present invention enlarges the effective display area of a CRT for projecting while maintaining the strength of the panel necessary to allow for normal usage without breaking. The inside portion of the effective display area inside the rectangular display area is of a predetermined radius, and protrudes inward, extending in all directions. The four corners of the display area are outside of the circular boundary line comprised of the standard thickness Tf. Non-display areas H which are outside the boundary line are flat or protuberant, and have a thickness greater than the standard thickness Tf. Accordingly, with the present invention, the effective display area A2 can be made larger than previous effective display areas A1 in the prior art, which could not extend beyond a border that included the four corners, while maintaining overall the necessary strength.Type: GrantFiled: September 22, 1994Date of Patent: September 3, 1996Assignee: Sony CorporationInventors: Koichi Iida, Michihisa Yano
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Patent number: 5528312Abstract: Beam scan velocity modulation (SVM) apparatus with a svm disabling circuit employed for picture sharpness enhancement is disclosed. The beam SVM includes a picture display device, a source of a first video signal having a picture information displayed on the device when the source is selected, an OSD/TELETEXT display generator having on-screen display information or teletext display information displayed on the device when the generator is selected, a scan velocity modulating circuit coupled to the source for modulating information displayed on the device in accordance with the video content of the first video signal, and a svm disabling circuit responsive to the pulses and the dc voltage and coupled to the scan velocity modulating circuit for modifying operation of the scan velocity modulating circuit when the OSD/TELETEXT display generator is selected.Type: GrantFiled: July 19, 1994Date of Patent: June 18, 1996Assignee: Daewoo Electronics Co., Ltd.Inventors: Gwan H. No, Hong W. Lee