Matsushita Electric Industrial Co., Ltd.

Matsushita Electronics Corporation

Kiyoshi Hamada

Kinzo Nonomura

Jumpei Hashiguchi

Satoshi Kitao

Ryuichi Murai

Masayuki Takahashi

Kaoru Tomii

Masanori Watanabe

Toshifumi Nakatani

Kanji Imai

Fumio Yamazaki

Tetsuya Shiratori

Takatsugu Kurata

Makoto Kawachi

Hironari Taniguchi

Seiichi Taniguchi

Junpei Hashiguchi

Michio Ohsugi

Riyuma Hirano

Minoru Katsuyama

An image display device has a plurality of electrodes that control a beam between a group of linear cathodes (,) and a screen (,) with a phosphor layer, and is provided with a circuit (,) for generating a beam track offset signal, which generates a signal for slightly oscillating one of the beams horizontally, a PIN photodiode (,) for detecting the emission amount of the phosphor layer for this beam, a comparator (,) for generating a beam irradiation position misalignment signal based on the detected emission amount, an integrating circuit (,) for generating a beam position control signal in correspondence with the beam irradiation position misalignment signal; and a horizontal deflection electrode driving circuit (,) for driving a horizontal deflection electrode (,) in accordance with the beam position control signal. With this configuration, misalignments of the position of the beam spot and the phosphor stripes on the screen, which are caused for various reasons, can be suppressed, and an image display device is obtained, in which a deterioration of the image quality, such as color misalignments, does not occur.

Image display

A driving circuit for a capacitive load includes an amplifier for applying voltage with large amplitude to the capacitive load in order to reduce the power consumption of the amplifier is disclosed. The driving circuit for the capacitive load applies the voltages Vout, Vout' amplified by a first amplifier and a second amplifier Q.sub.2, Q.sub.3, Q.sub.2 ', Q.sub.3 ' to a first capacitive load C, and a second capacitive load C'. The applied voltages Vout and Vout' have the opposite phase to each other. The driving circuit for the capacitive load includes a first emitter follower circuit Q.sub.1 and a second emitter follower circuit Q.sub.1 ' for converting the supplied voltage Vcc from the power supply source of the driving circuit to the voltage which is higher by predetermined voltages E.sub.1, E.sub.1 ' than the output voltage Vout, Vout' of the first amplifier and the second amplifier respectively. The driving circuit for the capacitive load includes a switching part using diodes D.sub.1 and D.sub.2 (D.sub.1 ' and D.sub.2 ') for switching automatically to connect the power supply terminal of the first amplifier (second amplifier) with either the output of the emitter follower circuit Q.sub.1 (Q.sub.1 ') or the second capacitive load C (the first capacitive load C').

Driving circuit for capacitive load

In a planar type display device, deterioration of the picture quality caused by distortion of laminated electrodes due to temperature rise in use is prevented by laminating the electrodes having such a structure that each electrode plate is free from expansion and contract by thermal expansion. Securing means spacers 23 thicker slightly than electrode plates are inserted in holes of the electrode plates 21a to 21e, securing means pin 24 is passed therethrough holding electrode plate spacers 22 therebetween, forming laminated electrode group 5. Since the respective electrode plates have slight gaps in a thickness direction and the electrode plates are free from expansion and contraction and do not distorted at the time of thermal expansion.

Planar type display device and its driving method

A flat tube display apparatus wherein a row of many electron beam generators is arranged transversely in a thin flat vacuum tube body to generate a number of beams in parallel with each other which travel in parallel with an image screen and to deflect the beams toward the image screen at a predetermined position. The beams are guided without being widely diverged due to the provision of a number of side walls arranged in parallel with each other to confine beams and due to the provision of alternately strong and weak magnetic fields along the side walls. Image brightness can be further increased by a frit-glass-laminated structure of a multiplier or microchannel.

Flat tube display apparatus

An image display device includes comb-shaped horizontal deflection electrodes disposed interleavingly in a first plane with a space therebetween for forming electron beam passages and comb-shaped vertical deflection electrodes disposed interleavingly in a second plane adjacent and parallel to the first plane. The capacitance between the horizontal deflection electrode confronting the vertical deflection electrodes and the capacitance between the horizontal deflection electrode confronting the vertical deflection electrode are made equal to each other. Also, the capacitance of the vertical deflection electrode confronting the horizontal deflection electrodes and the capacitance of the vertical deflection electrode confronting the horizontal deflection electrodes are made equal to each other, whereby the voltage effect induced by the other deflection electrode can be canceled and a good quality image can be obtained.

Image display device

A flat display panel assembly includes an evacuated glass envelope having a faceplate, a source of electron beams, a control electrode assembly including a stack of electrode substrates each having a predetermined pattern of electrode holes defined therein, and anodes formed by depositing phosphor material on the faceplate in correspondence with the electrode holes in the electrode substrates. At least one of the electrode substrates is made of a material having a coefficient of thermal expansion different from that of the remaining electrode substrates. The electrodes holes in such one of the electrode substrates are so defined and so arranged as to be offset from the corresponding electrode holes in the other electrode substrates by an increasing as a distance increases from a center portion of the electrode assembly towards the perimeter of the electrode assembly. With the electrode holes so defined and so arranged, the electrode substrates are movably supported to accomodate the thermal expansion.

Flat display panel assembly

A wire shaped electron source includes a heating core wire, an insulator partially provided on the heating core wire, and an electron emission material provided on the heating core between the insulators. The thickness of the electron emission material is less than the height of the insulators. When the wire shape electron source is installed in a flat panel display device, the insulator prevents the electron emission material from vibrating thus preventing any contact with the inner wall of the flat panel display device.

Wire shaped electron source

A flat panel display device includes a face plate made of a transparent material, a back plate positioned parallel to the face plate, and a wall member extending between the face plate and back plate to define an airtight housing. An anode is provided on a inner surface of the face plate, a fluorescent layer is provided in association with the anode, and a cathode is provided in association with an inner surface of the back plate. A plurality of struts, made of an electrically conductive screen printed powdery material, are tightly held between the back plate and the face plate, such that an electric charge accumulated between the anode and cathode is discharged by a leakage current flowing through the struts.

Flat panel display device

A method of driving an image display device is disclosed in which electron beams from line cathodes are impinged upon a display screen through beam modulating and deflecting electrodes to display an image. Each beam roughly lands onto a predetermined position on the screen by a stepped deflection voltage waveform to form a spot on the screen while the beam is deflected around the predetermined position by an unstepped deflection voltage waveform. The timing of application or the pulse width of a driving pulse signal for the beam modulating electrode is controlled in a form temporally related to the driving of the beam deflecting electrode to control the landing position or diameter of the spot on the screen. In the case where the driving pulse signal is a signal the pulse width of which is modulated by a video signal, the pulse width is changed in accordance with the level of the video signal and equally in positive and negative directions around the instant of time when a signal pulse having the minimum width necessary for representation as an image is to be generated.

Method of driving image display device

An image display apparatus which controls electron beams emitted from an electron source by electrodes having an arrangement of electron beam passage apertures and displays an image by irradiating the electron beams onto phosphors on a screen. The image display apparatus includes a means which changes at least a position of the electron beam passage aperture of a second electrode of the electrodes corresponding to the electron beam passage aperture of a first electrode of the electrodes in accordance with the position on the screen and controls the potential difference between the two electrodes, thereby making it possible to control the landing position of the electron beams on the screen.

Image display apparatus

During a period in which electron beam emission to a photo-emissive screen is inhibited, a heating current is supplied to a cathode. During a period in which electron beam emission to the screen is enabled, the supply of the heating current to the cathode is interrupted and the potential at the cathode is varied with a video signal. During the beam emission enabling period, the interruption of the heating current supply allows the electron beam to be uniform along the cathode, since the heating current would cause a potential gradient or variation along the cathode. In addition, during the beam emission enabling period, since the cathode potential is varied with the video signal, the electron beam is modulated in accordance with the video signal.

Display device and method of driving the same

A method of producing uniformity of emission a characteristics of a plurality of electron beam sources in a cathode ray tube, by deriving and storing data values for producing respective correction voltages to be applied to modify the emission characteristics. Each data value is obtained by sensing a current which flows through one of the control electrodes when a high voltage electrode is set to a relatively low potential, comparing this current with a reference value and storing the difference for use in subsequently producing a correction voltage. Data values are derived during successive time intervals, with corresponding correction voltages being successively applied to achieve feedback operation, for greater correction accuracy.

Method of driving a flat type of cathode ray tube to provide uniformity

Apparatus and method for substantially equalizing the potential drop along a line cathode used in an electron beam source adapted for use in a flat display device. The apparatus and method ensure that electrons from a power source are fed through both ends of the line cathode, substantially simultaneously. Thereby, the potential drop along the axial length of the line cathode is decreased, improving the uniformity of brightness of the display.

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Sakai, Japan

Kiyoshi Hamada