Cathode-ray Tube Display Excessive Voltage Control Patents (Class 348/377)
  • Patent number: 10356401
    Abstract: A method of operating a VR or AR head mounted display (HMD) system includes obtaining a video performance parameter for a video signal, selecting a clock frequency for video data transfer within the HMD system based on the video performance parameter, detecting one or more available frequency bands for a wireless data connection between a host device and the HMD system, and selecting a frequency band from the one or more available frequency bands for the wireless data connection, based on a predetermined connection suitability parameter for the one or more available frequency bands and based on the selected clock frequency for video data transfer within the HMD system. The method further includes establishing a wireless connection between the host device and the HMD system over the selected frequency band.
    Type: Grant
    Filed: August 16, 2017
    Date of Patent: July 16, 2019
    Assignee: FACEBOOK, INC.
    Inventors: Rui Zhang, Dong Yang
  • Patent number: 8917353
    Abstract: An image apparatus with reduced three-dimensional (3D) crosstalk includes a shutter control system including an infrared (IR) signal transmitter configured to receive from a display device for displaying two or more light-off sections and two or more light-on sections arranged alternately in one image frame, information corresponding to the light-off sections and the light-on sections, and to output an IR signal corresponding to the information, the IR signal corresponding to a start of a first light-off section of the light-off sections in the image frame, and a shutter controller configured to receive the IR signal, and to control opening or closing of a left shutter and a right shutter in accordance with the IR signal.
    Type: Grant
    Filed: December 8, 2011
    Date of Patent: December 23, 2014
    Assignee: Samsung Display Co., Ltd.
    Inventor: Hye-Jin Shin
  • Patent number: 7950029
    Abstract: A method of interactive television providing for generating, transforming or displaying video information taking into account individual peculiarities of the user's eye and individual peculiarities of a group of viewer's eyes. The method provides simultaneously all or, at least, two operations from the above operations of formation, conversion and transmission of video signal and display of video information perceptible on the screen of information display facilities for one and/or a group of users or an unrestricted group of users. This is accomplished by one or a combination of various video editing and transmission adjustment techniques.
    Type: Grant
    Filed: January 24, 2003
    Date of Patent: May 24, 2011
    Inventors: Aleksandr Ivanovich Andreyko, Andrey Olegovich Kostrikin
  • Patent number: 7663663
    Abstract: A burn-in control method and video processor for executing the same. The video processor intelligently recognizes aspects of a video image that are likely to cause burn-in, and responsive to such recognition, modifies the video image to prevent uneven aging of the pixels. According to one aspect of the disclosure, modifications are spatially made to an entire video frame, one or more selected regions of a video frame, or one or more individual pixels of a video frame. According to another aspect of the disclosure, modifications are temporally made to all frames in a video stream, selected frames in a video stream, or a single frame in a video stream.
    Type: Grant
    Filed: April 26, 2007
    Date of Patent: February 16, 2010
    Assignee: NVIDIA Corporation
    Inventors: Christian Prusia, Willie Thomas Glover
  • Patent number: 7468663
    Abstract: A building security system includes a visible video camera and a hidden video camera in each room. Personnel in each room carries a portable signaling device that includes a level sensor to automatically generate a signal indicating the personnel is down. Each room has remotely controlled door locks. All cameras, signaling devices and locks are linked to a security station including a router and computer. Police are provided with secure codes to obtain access to the computer, view the video and communicate with selected rooms in the building.
    Type: Grant
    Filed: November 9, 2006
    Date of Patent: December 23, 2008
    Inventors: Michael J. Rufolo, Jr., Michael J. Shannon
  • Patent number: 7187414
    Abstract: 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: Grant
    Filed: September 12, 2002
    Date of Patent: March 6, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Chang-joo Jung
  • Patent number: 7030908
    Abstract: Disclosed are a method and an apparatus for preventing appearance of a zigzag flush of light in a cathode-ray tube at the time of turning it off. A train of power-off control pulses are produced in synchronization with the vertical sweeping signal; a spot-killer control signal starts in synchronization with a selected power-off pulse to make the whole screen of the cathode-ray tube bright; and the power supply turns off in synchronization with another selected power-off control pulse, so that the power-off is caused at the termination of the vertical sweeping. Thus, the remaining static electricity is discharged at the lowermost of the screen of the cathode-ray tube. To assure that the residual static electricity is discharged completely, the length of time “t1” (continuing for a selected integer as long as the pulse-to-pulse duration) is determined to meet the size of the cathode-ray tube.
    Type: Grant
    Filed: March 19, 2003
    Date of Patent: April 18, 2006
    Assignee: Orion Electric Co., Ltd.
    Inventor: Kazuyuki Iji
  • Patent number: 6937288
    Abstract: In a beam current limiting circuit for a video projector, an average current is limited under closed loop control containing an anode current detection circuit 5. On the other hand, a cathode current detection circuit 107 comprises a first resistor and a second resistor in series to a cathode current circuit and detects a cutoff current at the voltage across the first resistor and an average current at the voltage across the second resistor. An offset addition circuit 11 is provided for correcting the detection value of the average current based on the maximum value of detected cathode current, and beam current is limited. Further, means 15 for detecting time change of anode current is provided and if the current value does not change for a long time, the beam current is limited to a smaller value.
    Type: Grant
    Filed: April 19, 2001
    Date of Patent: August 30, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Taketoshi Hibi
  • Patent number: 6897900
    Abstract: A display apparatus, for instance a television receiver, comprises a cathode ray tube, a first circuit for providing a high voltage to the cathode and a second circuit receiving a gross signal and providing on at least an output at least a luminance signal controlling an electron stream of the cathode ray tube. To reduce stray emission, absence of gross signal is simulated when the apparatus is switched from on to off.
    Type: Grant
    Filed: June 14, 2000
    Date of Patent: May 24, 2005
    Assignee: Thomson Licensing S.A.
    Inventors: Yew Honn Cheong, Kyaw Nyunt Maung
  • Patent number: 6888575
    Abstract: An improved digital cut-off control loop for black level adjustment in a video processor for controlling RGB output signals. The improved circuit advantageously provides a higher resolution of the black level adjustment, and a short cut-off convergence time when the TV set is switched on. The improved circuit can also blank the RGB output when the cut-off control loop has not converged to the correct level.
    Type: Grant
    Filed: September 25, 1998
    Date of Patent: May 3, 2005
    Assignee: STMicroelectronics Asia Pacific Pte. Ltd.
    Inventors: Yann Desprez-Le Goarant, Jean-Luc Jaffard, Christian Michon
  • Patent number: 6744429
    Abstract: A display device includes a display unit with a plurality of pixels for displaying picture images, a driving unit for controlling operation of the respective pixels of the display unit, a power control unit for supplying a power to the driving unit and the display unit while controlling the power, and an abnormal operation prevention circuit. The abnormal operation prevention unit prevents the pixels from being deteriorated in display characteristics due to interception of an input signal into the driving unit when the power is continuously supplied to the driving unit from the power control unit.
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: June 1, 2004
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Kwang-Hyun Ra
  • Patent number: 6636265
    Abstract: An inventive method for preventing focus flutter display in a TV receiver or monitor includes the steps of amplifying a received signal for driving cathode elements of a cathode ray tube, and delaying initial full amplification of the signal during the amplifying step for a duration sufficient to prevent focus flutter display on the tube. A corresponding inventive kine driver circuit that prevents display of focus flutter includes an amplifier for amplifying and coupling received video signals to cathode elements of a picture tube, and a control circuit for delaying full amplification of the video signals to be fed to the cathode elements for a duration sufficient to prevent focus flutter display on the tube.
    Type: Grant
    Filed: June 7, 2000
    Date of Patent: October 21, 2003
    Assignee: Thomson Licensing S.A.
    Inventor: Isaac Michael Bell
  • Publication number: 20030103143
    Abstract: An apparatus for controlling aging, cathode ray tube aging including a microcontroller generating brightness level data for aging of the cathode to a video input signal; a video preamplifier connected to the microcontroller receiving the brightness level data by the video input signal and mixing a host video signal to generate a video output signal wherein the brightness level of the video output signal being controlled by the microcontroller; a cutoff control coupled to the video preamplifier receiving brightness data of the video output signal and setting a proper brightness level of a cathode; and a voltage control not coupled to the microcontroller preset for a an initial brightness level of the cathode during aging.
    Type: Application
    Filed: December 5, 2001
    Publication date: June 5, 2003
    Inventors: Shin Fujimori, Hiyouki Nakazono, Toshinori Hamada
  • Patent number: 6563496
    Abstract: A cut-off adjusting apparatus in which a signal source for detecting cathode current is not required, the cost can be reduced, the cathode current can be detected with high precision, and the correction corresponding to time-variation can be performed with high precision. Includes a controller in which when an enforced adjusting mode is set, during a vertical period a control signal is output to a video amplifier to output such a signal that no video signal is contained in the output and the pedestal level is the black level irrespective of the input video signal, and wherein an averaged cathode current at this time is detected.
    Type: Grant
    Filed: July 14, 2000
    Date of Patent: May 13, 2003
    Assignee: Sony Corporation
    Inventor: Hisao Sakurai
  • Patent number: 6563495
    Abstract: A method and system for implementing a screen saver function is described. A peak value of a characteristic such as beam current magnitude of a video signal being processed is determined. An average value of the same characteristic of the video signal is also determined. Changes in this average value is additionally monitored. Therefore, the characteristic of the video signal is adjusted only if the peak value exceeds a first threshold and a change less than a second threshold is detected in the average value.
    Type: Grant
    Filed: November 9, 2000
    Date of Patent: May 13, 2003
    Assignee: Thomson Licensing S.A.
    Inventor: Dal Frank Griepentrog
  • Patent number: 6549246
    Abstract: In a projection CRT, an image of high brightness is displayed on a screen as an electron beam emitted from an electron gun is scanned according to an image driving signal. The image is magnified and projected through a lens unit. Here, voltage of a direct current component of the image driving signal is lower than threshold voltage of the screen for scan time and also lower than threshold voltage of the electron gun for retrace time.
    Type: Grant
    Filed: May 17, 1999
    Date of Patent: April 15, 2003
    Assignee: Samsung Display Devices Co., Ltd.
    Inventors: Sang-kyun Kim, Duk-sung Park
  • Patent number: 6473078
    Abstract: A method and a device for power management regarding an integrated display unit including a video display and at least one peripheral device, wherein the video display uses horizontal and vertical sync signals for the synchronization of the display images, and the peripheral device uses a peripheral signal to carry out its function. The peripheral device can be an audio unit using audio signals to produce sound. The peripheral device can be a USB connector using a +5 V voltage to indicate a connection being made to the integrated display unit. In the integrated display unit, a single power supply is used to provide electrical power to the video display and the peripheral device. In order to reduce the power consumption by the integrated display unit, a number of power consumption states, based on the presence of the video sync signals and the peripheral signals, are implemented. The presence of the video sync signals can be detected by a micro-controller in the integrated display unit.
    Type: Grant
    Filed: May 26, 1999
    Date of Patent: October 29, 2002
    Assignee: Nokia Display Products Oy
    Inventors: Raimo Ikonen, Jari Pistemaa, Turo Rantanen, Anders Engberg
  • Patent number: 6433827
    Abstract: A method for calibrating a screen grid voltage of the color picture tube in a color television set having automatic cut-off regulation. The method comprises the steps of, changing a normal operating potential at control electrodes of the color picture tube; adjusting the screen grid voltage about a value until values causing a fly-back line to be alternately visible and extinguished converge on the value; and, resetting the normal operating potential at the control electrodes of the color picture tube.
    Type: Grant
    Filed: April 5, 2000
    Date of Patent: August 13, 2002
    Assignee: Thomson Licensing SA
    Inventor: Gerold Lübcke
  • Publication number: 20020093586
    Abstract: A CRT device with an electron gun provided therein includes control means for controlling voltages applied to a cathode and a control electrode constituting the electron gun. The control means exerts control on each electrode voltage so that the difference between the cutoff voltage of the cathode and the voltage of the control electrode is greater when the luminance level of a luminance signal separated from picture signal is higher, thereby minimizing a spot diameter.
    Type: Application
    Filed: January 15, 2002
    Publication date: July 18, 2002
    Inventors: Masahide Yamauchi, Kazunori Ohta, Masahiko Sukeno, Takashi Itoh
  • Publication number: 20020060752
    Abstract: A display apparatus including a CRT is disclosed. The CRT includes an electron gun having a cathode, a G1 electrode, a G2 electrode and a G3 electrode disposed in that order to draw electrons from the cathode. The electron gun further has a modulating Gm electrode disposed between the G2 and G3 electrodes. The display apparatus is provided with a controller for controlling a value of a voltage applied to the Gm electrode to adjust brightness of a picture on a screen of the CRT.
    Type: Application
    Filed: March 28, 2001
    Publication date: May 23, 2002
    Inventors: Hironobu Yasui, Akinori Heishi
  • Patent number: 6392695
    Abstract: An image display device having (a) a DVD or a CD, (b) a television receiver, (c) a display for displaying an image from the DVD and the television receiver, (d) a screen burn-in preventer, and (e) a deterioration protector for protecting the display device from deterioration. The screen burn-in preventer discontinues reproduction from the DVD when an image reproduced of the DVD becomes stationary, and the stationary state continues for the predetermined time period. The deterioration protector discontinues reproduction from the DVD at a second predetermined time after the television receiver is turned on while an image reproduced from the DVD is displayed by the display.
    Type: Grant
    Filed: April 17, 1998
    Date of Patent: May 21, 2002
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toru Watamoto, Koichiro Nagata
  • Patent number: 6323915
    Abstract: A method and apparatus for displaying a video signal is described. A first video signal is received representing a first image having a first aspect ratio. The first image is displayed on a display having a second aspect ratio and a display area, with the first image having a smaller area than the display area forming a border area. A second video signal is received representing a second image having the second aspect ratio. A border modification signal is generated. The second image is displayed on the display with the border area modified in accordance with the border modification signal.
    Type: Grant
    Filed: September 24, 1999
    Date of Patent: November 27, 2001
    Assignees: Sony Corporation, Sony Electronics Inc.
    Inventors: Thomas Adreon Marflak, Hirohide Kiga, David Scott Arnold
  • Patent number: 6313878
    Abstract: A hardware-implemented screen-saver prevents burn-in of an image displayed on a screen of a display product by automatically reducing the video gain, and therefore the contrast, of the image when the portion of the image within a two-dimensional detection window has changed by less than a predetermined amount for a predetermined period of time. A lack of change of the incoming video signal of the image is detected and used to invoke a reduction in contrast of the image displayed on the display product. This allows the image to remain visible, yet reduces the possibility of burn-in of the image in the screen of the display product.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: November 6, 2001
    Assignees: Sony Corporation, Sony Electronics, Inc.
    Inventor: Patrick Joseph Jankowiak
  • Patent number: 6285401
    Abstract: Display apparatus includes a kinescope cathode current sensor (18) coupled to a load (200) for developing a beam current measurement pulse during a beam current measurement interval. Overshoots in the pulses are suppressed by a pulse correction circuit (300) comprising a first capacitor (Ca) coupled from the load circuit (200) to a source of reference potential (Gr) via a switch (Q300); and a control circuit (Ca, Ra, Rb), responsive to the presence of the overshoot, for closing the switch for a predetermined length of time and for opening the switch otherwise.
    Type: Grant
    Filed: December 30, 1998
    Date of Patent: September 4, 2001
    Assignee: Thomson Licensing S.A.
    Inventor: Dal Frank Griepentrog
  • Patent number: 6211908
    Abstract: 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: Grant
    Filed: May 27, 1999
    Date of Patent: April 3, 2001
    Assignee: Thomson multimedia Licensing S.A.
    Inventor: Dal Frank Griepentrog
  • Patent number: 6188435
    Abstract: A circuit for controlling beam current in a picture tube, which circuit calculates current pictures for the R, G, B beam currents in the picture tube, which largely correspond to real beam currents in the color picture tube. The circuit comprises a comparator/integrator which compares a sum of these current pictures with a beam current information item for the purpose of controlling the R, G, B beam currents and/or the picture sharpness. Gamma correction is carried out in the circuit. The circuit may be of analog or digital construction and may advantageously be integrated in a video processor IC. The present circuit is particularly applicable for television sets or computer monitors.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: February 13, 2001
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventors: Hossein Ahmari, Gerard Rilly
  • Patent number: 6091454
    Abstract: A television system for displaying images having adjacent horizontal blocks with sharp contrast. In general, such sharp contrasts can cause the drive voltage (Hv) applied to an anode of a CRT display unit to change. The changes typically result in distortions in the displayed images. A correction logic is employed to regulate the voltage source that supplies the voltage to the anode of the CRT display unit. The correction logic examines the digital data representation of the images to determine the extent of contrast, and supplies a corresponding correction voltage to regulate the voltage source. Due to the correction voltage, a constant drive voltage is supplied to the anode. The distortions are thus minimized or eliminated.
    Type: Grant
    Filed: December 31, 1997
    Date of Patent: July 18, 2000
    Assignee: TeleCruz Technology, Inc.
    Inventor: Bryan Michael Richter
  • Patent number: 6064581
    Abstract: A high voltage transformer (Tr) includes a primary winding (Lp), secondary windings (Ls1, Ls2, Ls3), and diodes (Di) coupled between successive secondary windings. The polarity of the diodes and the secondary windings is selected such that the flyback voltages across each of the secondary windings are summed via conductive diodes during at least a part of a flyback period (Tf) for generating a high voltage. A damp-circuit (1) comprises a rectifier element, a load (L), and a further winding (Ls4) of the high voltage transformer. These elements are arranged with respect to one of the secondary windings such that the further winding and the one of the secondary windings form a capacitance (Cd) across the load. The diode (D) is non-conductive during the flyback period. In this way, electrical oscillations of the high voltage transformer are damped.
    Type: Grant
    Filed: April 9, 1999
    Date of Patent: May 16, 2000
    Assignee: U.S. Philips Corporation
    Inventors: Pieter J. Bax, Rudi Jonkman
  • Patent number: 6057883
    Abstract: A circuit for controlling the picture tube in a television receiver. In order to generate a high peak white on the screen of the picture tube, it is desirable to drive the output amplifiers at full output. Because of tolerances, for example in the cutoff calibration, the transparency of the picture tube glass, fluctuations in the input signal etc., driving the video output stages to full output may drive the output stages into saturation and disturbances in the form of so-called smears can occur in the picture. The present invention permits the output stages to be driven to full output as far as the highest peak white without the output amplifiers going into saturation and causing disturbances in the form of smears in the picture.
    Type: Grant
    Filed: November 18, 1997
    Date of Patent: May 2, 2000
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventors: Bernd Fey, Helmut Sowig
  • Patent number: 6034729
    Abstract: A monitor protection system comprise a display power management signaling (DPMS) operating unit for performing a predetermined power control; a horizontal deflection detecting circuit for detecting a horizontal deflection signal from a horizontal deflection circuit; a vertical deflection detecting circuit for detecting a vertical deflection signal from a vertical deflection circuit; and a control circuit for determining whether the horizontal deflection signal and the vertical deflection signal are normal, and generating a predetermine control signal to run the DPMS operating unit in order to observe the conditions of horizontal/vertical synchronization signals continuously, and protect a CRT monitor independently from the horizontal/vertical synchronization input conditions.
    Type: Grant
    Filed: October 17, 1997
    Date of Patent: March 7, 2000
    Assignee: SamSung Electronics Co., Ltd.
    Inventor: Joon-Woo Lim
  • Patent number: 5889558
    Abstract: An image display is disclosed, in which a reference signal is superimposed on image signal in a fly-back period for controlling the bias voltage on the cathode of the CRT or the reference signal or the bias voltage on the grid G2 of the CRT such as to make the beam current in the CRT cathode to be constant by detecting the beam current in the reference signal period, while also obtaining brightness control. The image display comprises a stub pulse generator 2 for providing a stub on the black level side more than the image signal pedestal level, and an adder 3 for superimposing the stub pulse on the image signal. It is possible to change the reference signal voltage level to be on the black level side more than the image signal pedestal level, extend the brightness range, and obtain back luster float-up.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: March 30, 1999
    Assignee: NEC Corporation
    Inventor: Hiroaki Ikeda
  • Patent number: 5883669
    Abstract: A device having a display device employing a cathode-ray tube and an electron beam includes an on-screen display memory for storing data used to display white on an entire screen of the cathode-ray tube, a circuit for supplying signals used to display white on the entire screen of the said display device employing the electron beam based on the data stored in the on-screen display memory, and a controller for outputting a signal indicative of a command for displaying white on the entire screen from the on-screen display memory in accordance with a de-energizing operation. The signals used to display white on an entire screen of the cathode-ray tube are output to the display device employing the electron beam after the device having the display device is de-energized. Displayed contents are erased by removing a residual high voltage in the display device employing the electron beam.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: March 16, 1999
    Assignee: Sony Corporation
    Inventors: Noriyuki Hitachiya, Kunio Hakamada, Sumio Baba, Yoshiyuki Idenawa, Hirokatsu Kubota
  • Patent number: 5682083
    Abstract: A spot removing circuit for a display device is disclosed. The spot removing circuit comprises a rectifying and smoothing portion for rectifying and smoothing the voltage outputted from a flyback transformer, a capacitor for charging a voltage supplied from a power supply and discharging the charged voltage when the power supply switch is turned off, and a grid control portion for supplying a grid terminal with the voltage outputted from the rectifying and smoothing portion when a power supply switch is turned on and for supplying the grid terminal with the voltage discharged from the capacitor plus the output voltage from the rectifying and smoothing portion when the power supply switch is turned off so that a spot can be prevented from appearing on a display screen when the power supply switch of the display device is turned off.
    Type: Grant
    Filed: December 29, 1995
    Date of Patent: October 28, 1997
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Hyun-Gook Shin
  • Patent number: 5677730
    Abstract: An improved spot elimination circuit for preventing a spot from occurring on the screen of a cathode ray tube such as a monitor or television receiver at the instant that the deflection circuit is shut off. An input voltage is charged and discharged to supply a high voltage in negative polarity to a first grid of the cathode ray tube. The spot elimination circuit includes a flyback transformer having a separate turns portion additionally provided for generating a high voltage and utilizes the high voltage as an input to thereby supply a cut-off voltage to the first grid. Accordingly, the phosphor screen of the cathode ray tube is protected from excessive cathode luminance at a focused spot which can cause degradation of the screen.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: October 14, 1997
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Tae-jin Park
  • Patent number: 5671016
    Abstract: In a high voltage discharge circuit for a CRT, a power-off detecting circuit detects turning off of a power switch and outputs a power-off detection signal, to activate a luminance increasing section to increase the luminance of a video signal being outputted to the CRT at the time the power switch is turned off. Therefore, the high-voltage charges that remain applied between the anode and the cathode of the CRT after the power switch has been turned off discharge rapidly so that occurrence of afterglow can be reliably prevented.
    Type: Grant
    Filed: January 13, 1995
    Date of Patent: September 23, 1997
    Assignee: Funai Electric Co., Ltd.
    Inventor: Hirotsugu Suzuki
  • Patent number: 5430596
    Abstract: A CRT protector circuit for detecting an overcurrent or an overvoltage to a CRT to protect the CRT. A detector circuit is provided for detecting the overcurrent and the overvoltage, and when such is detected an abnormality detection output from the detector circuit is supplied to a control circuit which in turn controls a horizontal output circuit. The operation of the horizontal output circuit, provided on a primary side of a flyback transformer is, instantaneously broken by the control circuit according to the abnormality detection output from the detector circuit. When the frequency of generation of the abnormality detection output becomes a predetermined value or more, the operation of the horizontal output circuit is continuously inhibited. Accordingly, when the abnormal condition is temporary, a normal high-voltage generating operation can be automatically restored.
    Type: Grant
    Filed: January 5, 1994
    Date of Patent: July 4, 1995
    Assignee: Sony Corporation
    Inventors: Kenji Hamaguchi, Kiyoshi Ogishima
  • Patent number: 5394188
    Abstract: An anode voltage (high voltage) of a CRT is detected by a voltage division. When it is detected by a comparator that the reduction of the high voltage has exceeded the controlled range of a high voltage stabilizing loop, two switches will be on. When one switch is on, the controlling end of a processing circuit controlling the luminance will be low in the potential and the direct current level or amplitude of a video signal will be limited. Thereby, the luminance will be controlled and the high voltage will become high. Meanwhile, when the other switch is on, the ABL operating voltage will forcibly become low and, even after the two switches become off, the average level of the luminance will be controlled. Thereby, the high voltage will return within a short time into the controlled range of the high voltage stabilizing loop and will be stabilized.
    Type: Grant
    Filed: June 10, 1993
    Date of Patent: February 28, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yoshifumi Ohira
  • Patent number: 5353187
    Abstract: A first transformer is coupled to a deflection yoke and coupled to a derived secondary voltage source for driving a load, for example, for generating an ultor voltage. An on/off switch is responsive to an on/off signal. A second transformer has a primary winding coupled to the switch and coupled to a voltage source and has a secondary winding coupled to the first transformer. A first sampling circuit generates a first feedback signal indicative of current flowing from the secondary winding to the first transformer. A first safety circuit responsive to the first feedback signal controls the effect of the on/off signal on the switch when the current flowing from the secondary winding to the first transformer exceeds a threshold, by limiting the on time of the switch to limit the peak value of the current. A second sampling circuit generates a second feedback signal indicative of the ultor voltage.
    Type: Grant
    Filed: October 11, 1991
    Date of Patent: October 4, 1994
    Assignee: Thomson Consumer Electronics S.A.
    Inventors: Jean C. Favreau, Friedrich Meinertz, Chon S. Oh
  • Patent number: 5313294
    Abstract: An automatic beam current limiting arrangement of a television receiver or display monitor comprises an average beam current limiter coupled to the low side of the high voltage transformer for reducing the contrast of a reproduced image when the average beam current exceeds a threshold and a peak current limiter coupled to the cathodes of the picture tube for controlling a current source which determines the threshold of the average beam current limiter in response to the sum of the cathode currents of the picture tube. In one embodiment, the cathode current sensing circuits comprise the same cathode current sensing circuits utilized in an automatic black level setting arrangement. This beam limiting arrangement allows operation at high contrast levels while inhibiting excessive peak white areas.
    Type: Grant
    Filed: January 14, 1992
    Date of Patent: May 17, 1994
    Assignee: RCA Thomson Licensing Corporation
    Inventor: Peter E. Haferl
  • Patent number: 5304898
    Abstract: The objects of the present invention are achieved by forming a high voltage generating circuit which comprises: a flyback transformer having a primary winding and a secondary winding; means for supplying pulses of first frequency to the primary winding; a smoothing capacitor connected across the secondary winding; an output line connected to one terminal of the smoothing capacitor; means for detecting a variation of high voltage on the output line to generate compensating voltage pulses of a second frequency which is higher than the first frequency for compensating the variation of high voltage to supply the compensating voltage pulses to the other terminal of the smoothing capacitor. Additionally, a low pass filter is connected between the other terminal of the smoothing capacitor and the secondary winding, which prevents the compensating voltage pulses from being supplied to the secondary winding.
    Type: Grant
    Filed: November 20, 1992
    Date of Patent: April 19, 1994
    Assignee: International Business Machines Corporation
    Inventors: Rieko Kataoka, Masaki Kobayashi