Sony Corporation

Lg Electronics Inc.

Katsuo Isono

Seiji Sanada

Tomoyoshi Imayasu

Ichiro Mitamura

Jung Gwan Han

Kazuo Yamagiwa

Toshiyuki Yamauchi

Hideshi Tamaru

Senri Miyaoka

Takashi Hosono

Susumu Akazawa

Kinya Shinkai

Kunihiro Yoshizawa

Kouji Morita

The present invention relates to a plasma display apparatus and driving method thereof, wherein rising and/or falling times of data pulses applied to address electrodes in an address period are controlled to reduce noise generation. Thus, address discharge is stabilized, discharge efficiency of plasma display panel is enhanced, and electrical damage to data drive ICs is prevented. The plasma display apparatus includes a plasma display panel including a plurality of address electrodes, a data driving unit including a plurality of data drive ICs that has a plurality of channels, wherein the data drive ICs are electrically connected to the address electrodes through the channels and drive the address electrodes, and a data pulse controller that controls the voltage-rising time and/or the voltage-falling time of the data pulses applied to the plurality of the address electrodes in an address period to be a sufficient duration, e.g. 100 ns or longer, by controlling the data driving unit.

Plasma display apparatus and driving method thereof

A method and an apparatus of re-adjusting convergence of a projection TV are disclosed. The apparatus includes a display device on which an image is projected and at least one light-sensing element () being provided around the display device. The light-sensing element () is composed of first and second sub-sensors () that generate separate output signal projected alignment pattern moves over the sub-sensors (). The apparatus further includes a microprocessor calculating a convergence re-adjustment vector by obtaining a location of the light-sensing element (), from which a previous convergence correction was made. The location of the light-sensing element () is obtained by analyzing the output signals. By using the apparatus and method of present invention, the misconvergence of the projection TV can be corrected very quickly and precisely.

Apparatus and method of re-adjusting convergence of a projection TV

The present invention relates to a power supply having a plurality of converters which is capable of easily setting a load share of each converter and simplifying the construction of the circuit, thereby reducing the cost. A DC source circuit having such a power supply includes a plurality of converters (each having a transformer, switches for interrupting a DC input and supplying the same to a first side of the transformer and a rectifier circuit for rectifying a voltage outputted from a second side of the transformer), an output circuit which cascade-connects each output voltage of the plurality of converters and thereby obtains a composite output voltage V,, and a common control circuit for feedback-controlling the plurality of switches as a function of the composite output voltage, e.g., according to the difference between the composite output voltage and the reference voltage. A load of each converter is shared according to each set output voltage. In addition, the cost of the power supply can be reduced by commonly using the control circuit.

Thin, cascade-connected direct current source circuit

A beam index type color television receiver having a beam index type color cathode ray tube which includes a screen having a plurality of groups of color phosphor elements and index phosphor elements, an index signal sensing device for detecting index signals from the index phosphor elements and generating index pulses, a frequency multiplier for providing a timing signal with a frequency that is a multiple of the frequency of the index pulses, a gate signal generator supplied with the timing signal from the frequency multiplier and generating a plurality of gate signals, a gate circuit for sequentially selecting, response to the gate signals three primary color signals desired from an input video signal and supplying the selected primary color signals to the cathode ray tube, and a velocity modulating device for modulating the beam scanning velocity of the cathode ray tube. To control the modulation of the beam scanning velocity, a video signal level detecting circuit detects the level of the input video signal, and a velocity modulating signal generating circuit supplies a velocity modulating signal to the velocity modulating circuit in response both to the output of the video signal level detecting circuit and to the timing of the index pulses.

Beam index type color television receiver

A side pincushion correcting circuit is provided in a color television receiver of the type including a cathode ray tube having an index stripe disposed on a screen scanned by a cathode beam and a detector for detecting the scanning of the index stripe by the cathode beam and producing a pulse signal as a result of such detecting. The side pincushion correcting circuit comprises a pulse forming circuit for generating a reference signal in correspondence to the pulse signal from the detector, a phase comparator for comparing the phase of the reference signal to that of a control pulse, such as the horizontal flyback pulse, associated with the commencement of scanning in the horizontal direction, and providing an output signal whose magnitude is proportional to the phase difference between the reference signal and the control pulse, and a horizontal deflection circuit supplied with the output signal from the phase comparator for controlling the scanning of the cathode beam in the sense to correct for side pincushion distortion.

Side pincushion correcting circuit for color television receivers

In a beam index color television receiver of the type having a cathode ray tube provided with beam-excitable color elements disposed on an image area of a display screen of the cathode ray tube and index elements disposed on the image area and a contiguous run-in area of the display screen, both of the color elements and index elements being scanned by the electron beam as the beam scans the display screen, apparatus for controlling the electron beam includes an index signal generator for generating a periodic index signal as the index elements are scanned by the beam, a phase-locked loop for producing an output signal having a frequency related to the index signal, color gates which sequentially gate respective color control signals individually to modulate the electron beam as the beam scans the color elements, a gating signal circuit which generates sequential gating signals at a frequency synchronized with the frequency of the output signal from the phase-locked loop and which supplies the gating signals in sequence to the color gates to control the latter so as to gate the respective color control signals, and a pulse forming circuit for enabling the phase-locked loop to produce the aforementioned output signal when the electron beam begins scanning the run-in area and for controlling the gating signal circuit to supply the gating signals to the control gates in phase alignment with respect to the scanning of the color elements when the electron beam begins scanning the image area of the display screen.

Beam index color television receiver

A horizontal scanning rate correction apparatus for a cathode-ray tube, particularly of the beam index color cathode-ray tube type, includes a memory for storing correction values representing deviations of the horizontal scanning rate of the electron beam from a desired scanning rate at each of a plurality of horizontal sampling positions along each of a plurality of predetermined horizontal sampling lines which are substantially fewer in number than the horizontal lines along which scanning occurs. During display of a video signal, a selected one of the stored correction values is read out of the memory for each scanning position of the beam along a scanned one of the horizontal lines, with each read correction value, and a corresponding sampling line correction signal produced therefrom, representing the deviation at a corresponding horizontal sampling position on one of the sampling lines. A scanned line correction signal is then produced for each horizontal scanning position which is a function of the sampling line correction signal and of the vertical position of the respective scanned line, and the scanned line correction signal is applied to the beam deflection yoke or device to substantially cancel the scanning rate deviation.

Horizontal scanning rate correction apparatus

Horizontal scanning rate correction apparatus is provided for beam index color cathode-ray tubes of the type having a screen, an electron gun for projecting an electron beam upon the screen, a plurality of index elements positioned to be struck by the electron beam as it scans across the screen, a deflection device for causing the electron beam to repeatedly scan across the screen in a vertical succession of horizontal lines, and an index signal processing circuit for producing an index signal having a frequency determined by the frequency of the incidence of the electron beam upon the index elements as it scans horizontal lines and for controlling color switching circuitry which determines which of a plurality of color signals modulates the intensity of the electron beam. The horizontal scanning rate correction apparatus includes a memory circuit for storing correction values derived from the index signal processing circuit during horizontal scanning by the electron beam and representing the deviation of the horizontal scanning rate from a desired scanning rate at each of a plurality of horizontal sampling positions along a horizontal line. The apparatus further includes circuitry for reading the correction values from the memory circuit and for producing a corresponding signal which is supplied to the electron beam deflection device to substantially cancel deviations in the horizontal scanning rate.

Horizontal scanning rate correction apparatus for beam index color

In a beam index color television receiver of the type having a cathode ray tube which is provided with beam-excitable color elements and index elements disposed on a display screen of the cathode ray tube and which are scanned by an electron beam; color switching is controlled by an index signal generator, comprised of a photo-detector and band-pass filter, for generating a periodic index signal as the index elements are scanned by the beam, color gates which sequentially gate respective color control signals individually to modulate the electron beam as the beam scans the color elements, a gating signal circuit including a phase-locked loop which generates sequential gating signals at a frequency synchronized with the frequency of the periodic index signal and a gate pulse generator which supplies the gating signals in sequence to the color gates to control the latter so as to gate the respective color control signals, and a phase-controlling circuit for imparting a phase shift to the gating signals supplied to the gating pulse generator to compensate for an inherent time delay caused by the photo-detector, band-pass filter and phase-locked loop. Such phase shift may be imparted by a phase shifter connected between the phase-locked loop and the gate pulse generator or at a voltage controlled oscillator in the phase-locked loop itself.

Beam index color television receiver apparatus

In a beam index color television receiver of the type having a cathode ray tube which is provided with beam-excitable color elements disposed on a display screen of the cathode ray tube and index elements which are scanned by an electron beam as the beam scans the display screen, an apparatus for controlling the beam includes an index signal generator for generating a periodic index signal as the index elements are scanned by the beam, color gates which sequentially gate respective color control signals individually to modulate the electron beam as the beam scans the color elements, a gating signal circuit which generates sequential gating signals at a frequency synchronized with the frequency of the periodic index signal and which supplies the gating signals in sequence to the color gates to control the latter so as to gate the respective color control signals, and a phase-controlling circuit for controlling the phase of the gate pulse signals in response to the highest-level one of the color control signals.

An index signal amplifier arrangement is disclosed for use in a beam index color television receiver of a type which includes a picture reproducer having index stripes disposed to be scanned by an electron beam and a photodetector for detecting when respective index stripes are scanned by the beam to produce an index signal. A local oscillator generates a local oscillating signal which is mixed with the index signal produced by the photodetector. The mixed signal is amplified by a band-pass amplifier, the latter preferably being formed of a band-pass filter having a predetermined, limited pass-band characteristic substantially centered on the expected frequency of the mixed signal, and a limiter amplifier coupled to the band-pass filter for removing amplitude modulations from the filtered mixed signal. Another mixer is coupled to the band-pass amplifier and also to the local oscillator for mixing the amplified mixed signal with the local oscillating signal to produce an amplified index signal having the index frequency. If the local oscillating signal frequency can be adjusted to 'match' the particular picture reproducer which is used in the color television receiver, then the frequency of the mixed local oscillating and index signals will be constant from one picture reproducer to the next. Consequently, a standardized, or uniform band-pass amplifier may be provided for all picture reproducers.

Index signal amplifier for use in a beam index television receiver

In a color television system having a video tape recorder and a color television receiver which includes an automatic control circuit for automatically controlling color level and hue with a reference signal contained in a predetermined horizontal scanning line section of a video signal, and which is so designed that a broadcasting signal and a reproduced signal of the video tape recorder are selectively received by the color television receiver, the automatic control circuit rendered inoperative in response to a change-over operation by which the color television system is changed over to apply the reproduced signal of the video tape recorder to the color television receiver.

Color television receiver and VTR system

Hue and color saturation are controlled in response to a received VIR signal, the latter having a chrominance reference portion and a luminance reference portion. The level of a preselected one or more demodulated color signals which are produced by the color demodulator in color video signal receiving apparatus is detected during the time that the VIR signal is received. The level-detected demodulated color signal is used to produce a control signal for controlling the hue or color saturation. A storage circuit, such as a capacitor, is provided to store the control signal throughout the duration which separates successive VIR signals. A VIR detector is provided for detecting the presence of a VIR signal in the received video signal; and when the absence of a VIR signal from the received video signal is detected, the control signal storage circuit is preset to a predetermined value. By so presetting the storage circuit, the time required for successful VIR-controlled color correction is minimized when the video signal receiving apparatus is switched from, for example, one broadcast channel which does not include a VIR signal to another broadcast channel which does include a VIR signal. In a preferred embodiment, both hue and color saturation are controlled in response to a VIR signal. The level of a selected color difference signal (R-Y), produced during the chrominance reference portion of the VIR signal, is used to control hue; and the level of a simulated color drive signal (B), also produced during the chrominance reference portion of the VIR signal, is used to control color saturation.

VIR-Controlled color correction for color video signal receiving

In a color video display device, such as a television receiver or a monitor associated with a color video tape recording and reproducing apparatus, and which is responsive to a composite color video signal including a luminance component and a chrominance component containing a chrominance signal, a burst signal and a chrominance reference portion of a vertical interval reference (VIR) signal; a hue-correction circuit is provided for dynamic correction of chrominance phase errors. The hue correction circuit includes a phase comparator that provides an output in response to the phase difference between the burst signal and the chrominance reference portion of the VIR signal, an oscillator for providing a continuous wave at the frequency of the burst signal, a controlled amplifier acting on the luminance component and having its gain controlled by the output of the phase comparator to provide a correction signal, and a phase modulator for adjusting the phase difference between the chrominance signal and the continuous wave signal in response to the correction signal. The phase comparator can include first and second sample-and-hold circuits for sampling the chrominance phase during the burst signal and during the chrominance reference portion of the VIR signal, respectively. The hue correction circuit can also include a clamp for clamping the output of the controlled amplifier to a reference level during the burst signal.

Hue correction circuit

Color control apparatus for use in color video receiving apparatus of the type capable of receiving a color video signal which includes a VIR signal, the latter having at least a chrominance reference signal therein. A chrominance channel is provided for processing the chrominance component included in the color video signal. An extracting circuit connected to the chrominance channel separates burst and chrominance reference signals from the received color video signal. A predetermined parameter in the separated burst signal is detected, and a corresponding parameter in the chrominance reference signal is detected. A common amplifier is responsive to the detected parameters for producing an amplified control signal which, in turn, is supplied to an adjustable circuit so as to adjust a color characteristic of the processed chrominance component in accordance with the amplified control signal. The detected parameters may be the level of the respective burst and chrominance reference signals, which levels are detected by comparison with a reference level. The detected burst signal level thus is used in an automatic chrominance control circuit, and the detected chrominance reference signal level is used in a color saturation control circuit, both of these control circuits being connected with the common amplifier for controlling the color saturation level of a processed chrominance component. Also, the detected parameter may be the respective phases of the burst and chrominance reference signals with respect to a local oscillating signal used for demodulating the chrominance component. In that event, the detected burst signal phase and chrominance reference signal phase are used in automatic phase control and hue control circuits, respectively, both of these control circuits being connected to the common amplifier. In a preferred embodiment, the color control apparatus includes an ACC and a saturation control circuit connected to one common amplifier for controlling color saturation, and an APC circuit and a hue control circuit connected to another common amplifier for controlling the hue characteristic of the ultimately demodulated color signals.

Growing community of inventors

Kawagoe, Japan

Katsuo Isono