Hitachi, Ltd.

Hitachi Video and Information Systems, Inc.

Advanced Pdp Development Center Corporation

Kiyoshi Watanuki

Kazuyoshi Takizawa

Michitaka Ohsawa

Yoichi Nakamura

Hirokazu Inoue

Kouichi Yamamoto

Sousuke Hisamatsu

Yukio Akiyama

Mitsugi Kojima

For a drive circuit of a sustaining discharge circuit of an AC plasma display panel, an idea of current flow parts arrangement is provided to reduce inductance. The configuration includes a plasma display panel on which electrodes are formed, an electric conductive conductor for fixing the panel, a pair of circuit boards fixed onto the conductor using a plurality of fixing members, ground terminals and electric power supplies disposed respectively for the circuit boards, and a pair of connecting circuit boards connected to end portions respectively of the circuit boards and an end portion of the panel. The ground terminals are electrically connected via fixing members to a position near an end portion of the conductor.

Plasma display apparatus

A liquid crystal projector, comprising: a liquid crystal panel; a light source for irradiating light onto an image formed on the a liquid crystal panel; a projection lens for enlarging and projecting the image projected from the liquid crystal panel; a cooler, such as a suction fan, for sending cooling air flow onto a panel surface of the liquid crystal panel; an air velocity sensor for sensing air velocity of the cooling air flow sent onto the liquid crystal panel; and a protection device for protecting the liquid crystal panel on a basis of a detected value of the air velocity measured by the air velocity sensor. The is further formed an air passage for passing the cooling air flow along with the panel surface of the liquid crystal panel, and the air velocity sensor is positioned in an exit portion of the cooling air flow passing through the liquid crystal panel.

Liquid crystal projector having a cooler and an air velocity sensor

A stacked or laminated-layer type of flyback transformer includes a plurality of high voltage windings wound in regular order in a direction of the winding axis and arranged on the same core cylinder. The high voltage windings in the respective layers are connected in series with each other by diodes and so that a voltage is generated with a direction of stacking of these windings. A winding start position of the first layer high voltage winding nearest a primary winding is lagged with respect to the winding start positions of the second layer winding and subsequent layer winding. The winding start position of the first layer winding is selected to be the position of, for example, 0 to 25% when the winding width on the core cylinder is 100%.

Display device including flyback transformer constructed to control

A terminal of the vertical deflection coil is connected to an integrating circuit, which generates a saw-tooth signal from the vertical deflection current for vertical synchronization. The saw-tooth signal is supplied to the clipping circuit having a diode so as to clip its waveform. The clipped signal and said parabolic signal are summed by an adding means in order to generate a correction signal. The correction signal is amplified with an amplifying transistors and supplied to the primary winding of the transformer, the secondary winding of which is serially connected to the horizontal deflection coil. The waveform of the signal that is summed up, is similar to the form of the pin cushion distortion indicated on the raster of a non-spherical CRT. Therefore, the correction singal modulates the amplitude of a current flowing through the horizontal deflection coil, so that the pin cushion distortion can be corrected on the luster.

Correcting circuit of pincushion distortion

In a high voltage generator comprising a flyback transformer having a primary winding and a secondary winding, a horizontal deflection circuit connected to the primary winding of the flyback transformer, and a rectifier diode connected to the secondary winding of the flyback transformer, a resonance circuit including a saturable transformer and a capacitor is inserted between the primary winding of the flyback transformer and a power source, and a signal corresponding to the value of a high voltage load current is applied to a control winding of the saturable transformer. When the value of the high voltage load current is very small, the resonance circuit resonates with a higher harmonic of a flyback pulse to remove this higher harmonic component. As the value of the high voltage load current increases, the inductance value of the secondary winding of the saturable transformer changes to change the resonance frequency of the resonance circuit. As a result, the proportion of removal of the higher harmonic component decreases to increase the peak value of the high voltage thereby suppressing a voltage drop of the high voltage.

High voltage generator

In a horizontal output circuit for a cathode ray tube, there is included a second resonant circuit combining in parallel a transistor, a damper diode, a resonant capacitor and a series connection of a capacitor and a coil serially connected to a horizontal deflection resonant circuit having a horizontal output transistor, a damper diode, a resonant capacitor, a series connection of an S-shape capacitor and a horizontal deflection coil and a flyback transformer. The constants of the circuits are set so that waveforms of resonant pulses generated by the two resonant circuits becomes similar. A parabolic correction voltage for vertical synchoronization is also applied to the second resonant circuit and the resonant pulse is amplitude-modulated parabolically by the vertical synchronization signal. Therefore, the resonant pulse of the first resonant circuit is amplitude-modulated parabolically with a reverse polarity. A current flowing into the horizontal deflection coil in the first resonant circuit is amplitude-modulated parabolically with a reverse polarity with that of the second resonant circuit and thereby right and left pin cushion distortion of raster can be corrected.

Horizontal output circuit for correcting pin cushion distortion of a

In a horizontal deflection circuit having a series circuit of a horizontal deflection coil and S-shape capacitor and a parallel circuit of a switching element and a second capacitor connected in series with said series circuit, there is provided a resonation circuit having a resonating frequency with the second capacitor that is substantially equal to the horizontal deflection frequency or a little lower than that for purposes of regulation of the high voltage of the cathode ray tube.

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Yokohama, Japan

Kiyoshi Watanuki