Hitachi, Ltd.

Kunio Ando

Hitoshi Maekawa

Michitaka Osawa

Fumio Inoue

Kenichi Fukuzawa

Masakazu Fukushima

Michitaka Ohsawa

Masaro Kaku

Takashi Sasaki

Koichi Maruyama

Nobuaki Kabuto

Keizo Suzuki

Masatoshi Shiiki

Soichi Sakurai

Masaji Ishigaki

Nobutaka Okuyama

Seiichi Yasumoto

Kuniharu Osakabe

Hiroshi Jitsukata

Toyota Honda

Masao Obara

Toshiharu Shimizu

Takeo Masuda

Ryoichi Hirota

Hiroyuki Miyajima

Mayumi Igarashi

Yasumasa Sawaki

Etuo Funada

Hiroki Ooguro

In an operation of an address period for addressing cells of a display device, such as a plasma display panel, comprising a plurality of cells of three kinds, red (R), green (G), blue (B), which are arranged on a plane for forming a display surface thereof, in which each of said cells comprising: a pair of transparent electrodes provided in parallel to each other; an address electrode being positioned opposing the pair of transparent electrodes; luminescence medium provided on the address electrode; and a discharge space being defined between the pair of transparent electrodes and said fluorescence medium on the address electrode, wherein the address discharge is conducted by applying an address voltage to the address electrode, and the address voltage applied is determined depending upon the each kind of the cells, R, G and B.

Display device and driving method thereof

In a display panel including a plurality of signals lines along a column direction and a plurality of scanning lines along a row direction for applying a display signal to display elements forming pixels arranged in a matrix form of rows and columns on a substrate, a switching arrangement for connecting at least two display elements to a signal line in each row is line-sequentially scanned by the scanning lines so that the display signal is time-serially applied through the same signal line to each of the at least two display elements connected to that signal line. Thereby, total number of the signal lines can be reduced to a value equal to or smaller than the number of display elements in the row direction.

Display device with matrix-arranged pixels having reduced number of

A driving circuit uses an output transistor and a driving transformer with a secondary coil being connected to the base of the output transistor. In order to get a high speed switching circuit without thermal runaway, the storage period of the output transistor is detected. A signal supplied to a primary coil of the driving transformer, for example, a driving pulse, is controlled in response to the detected value of the storage period. By minimizing the value of the storage period, it becomes possible to minimize a fall time of the output transistor, so that a stability of the driving circuit can be maintained.

Transistor driving circuit and circuit controlling method

A deflection yoke unit to be mounted on a cathode ray tube has a core on which a set of vertical deflection coils and a set of horizontal deflection coils are wound. A pincushion distortion correction device is provided for the deflection yoke unit. The correction device has a set of correction coils having a coil conductor mass quantity and an inductance which are smaller than those of the vertical deflection coil set and having a winding density distribution which is similar to that of the vertical deflection coil set. An upper and lower pincushion distortion correction current is passed through the correction coil set to correct upper and lower pincushion distortions in pictures displayed on a screen of the cathode ray tube. The core has, on its inner wall, slots in which windings of the horizontal deflection coil set, vertical deflection coil set and correction coil set for correction of the upper and lower pincushion picture distortions are received. A plurality of winding guide claw members having each two or three slots are attached to a front open end and a rear open end of the core, respectively. Front end conductors of the respective coil sets are separately placed in the slots at the front open end of the core and rear end conductors of the respective coil sets are separately placed in the slots at the rear open end of the core.

Pincushion distortion correction device

A drive circuit having a transformer with its secondary winding connected to the base of a transistor and its primary winding connected to a drive source by which the transistor is driven to switch, wherein a directional element is connected between a tap provided on the secondary winding and one end of the secondary winding so as to select the ratio between the forward base current and reverse base current of the transistor.

Drive circuit for driving a transistor

A cascode amplifier comprises a grounded-emitter drive transistor which has a collector supplied with a bias current from a bias current source and operates in response to an input signal and a grounded-base (or grounded-gate) output transistor which has a collector supplied with a bias current from a constant voltage source, wherein the collector of the drive transistor is connected to the emitter (or source) of the output transistor. A constant current circuit is connected to the junction between the collector of the drive transistor and the emitter (or source) of the output transistor for supplying a part of the bias current applied to the drive transistor to thereby decrease the bias current of the output transistor while causing the drive transistor to be operated in the linear region. The cascode amplifier is thus imparted with a broad band frequency characteristic.

Cascode amplifier with an improved biasing arrangement

An amplitude-adjusting circuit used for a contrast-adjusting circuit of resistor division type in which a video signal is applied across a pair of series-connected resistors and an output is produced from the junction point of the two resistors. At least one of the resistors is used as a variable resistor. The amplitude-adjusting circuit comprises a current source for supplying a constant current steadily between the terminals of the variable resistor, a high-gain amplifier for controlling the resistance value of the variable resistor, and a filter for separating the video signal component from the change of the value of the variable resistor represented by a voltage change, and introducing the resistance change to the high-gain differential amplifier.

Amplitude adjusting equipment in a signal translation line

A frontal light extraction type beam-indexing color picture tube arrangement comprises a phosphor screen which is formed on the inner surface of the tube panel and includes an array of color phosphor stripes each of which has an appropriate afterglow time and an array of index phosphor stripes each of which has a short afterglow time and emits a light index signal representative of the scanning position of an electron beam in the forward direction of the tube panel. A photoelectric converter for receiving the light index signal is provided in front of the tube panel.

Beam-indexing color picture tube arrangement

A horizontal deflection circuit comprises a horizontal oscillator circuit, a drive transistor, a horizontal output transistor driven by the output of the drive transistor, a timing circuit for setting a timing delayed by about one fourth the horizontal scanning period from the terminating point of the flyback pulse generated at the collector of the horizontal output transistor, a phase difference detector circuit for detecting the phase difference between the leading edge of the collector pulse of the horizontal drive transistor and the timing set by the timing circuit, and a pulse duration variable output circuit triggered by the output of the horizontal oscillator circuit and with the output pulse duration thereof controlled by the output of the phase difference detector circuit. The horizontal drive transistor is driven by the output of the pulse duration variable output circuit, so that the leading edge of the collector pulse of the horizontal drive transistor is rendered to coincide with the timing set by the timing circuit.

Horizontal deflection circuit

A switching regulator which chops an unstabilized D.C. input voltage by a switching transistor and rectifies the chopped voltage to produce a stabilized D.C. output voltage is disclosed. A series circuit of a resistor, a capacitor and a coil is inserted between a stabilized D.C. output terminal and a base electrode of an exciting transistor which excites the switching transistor to suppress the increase of a ripple voltage produced when the unstabilized D.C. input voltage drops.

Switching regulator

A beam-indexing color television receiver having a phosphor screen including one index stripe for every predetermined integral number of phosphor stripe sets each including a red, a green and a blue phosphor stripe. The minimum bias current is supplied to the picture tube only upon detection of a chrominance signal within a predetermined hue range around a specific chrominance signal corresponding to the phosphor stripe which is in the middle between adjacent index stripes on the phosphor screen, thus attaining a superior color saturation and contrast.

Beam-indexing color television receiver

In an electron gun for cathode-ray tube comprising a lens system constructed by four cylindrical electrodes concentrically arranged apart from each other for focusing electron beams emitted from a cathode, these electrodes are applied with proper voltages so as to form a bipotential type focusing lens and a unipotential type focusing lens. Preferably, the length of the electrode in the unipotential type focusing lens lying at the cathode side is selected to be larger than a half of the inner diameter of the electrode.

Electron gun for cathode-ray tube

Improvements in an electron gun assembly for a color picture tube comprising three electron guns arranged in an in-line relation, each of said three electron guns having three grid electrodes which have respective cylindrical portions of the same inside diameter and are arranged spacedly from each other on the same axis, and the non-central two of which are kept at the same electric potential. At least one of the non-central two grid electrodes is not required to be provided with an inner electrode so that it consists only of cap electrodes, and height i.e. the axial length of the inside cylinders of the respective cap electrodes of the non-central electron guns and the central electron guns are selected to be individually less than the inside diameter (D) of the electrodes.

Electron gun assembly for a color picture tube

In a unipotential type electron gun including a main lens constituted by three coaxial and spaced apart electrodes for focusing an electron beams, the length of the intermediate electrode is made to be larger than 1.1D, where D represents the inner diameter of the electrodes on both sides, and the sum of the length of one electrode located on the side of a cathode electrode, the length of the intermediate electrode, the gap length therebetween, and the gap length between the intermediate electrode and the electrode on the opposite side is set to be in a range of from 4.0D to 5.4D.

Electron guns for use in cathode ray tubes

A color picture tube of an in-line type comprises means for deflecting beams of electron emitted from electron guns of the in-line type aligned horizontally such that for the horizontal deflection, the central beam is subjected to a greater deflection than side beams and for the vertical deflection, the side beams are subjected to a greater deflection than the central beam. Two vertical magnetic pole piece plates which are long vertically and thin horizontally are so disposed as to sandwich the central beam near the outlet of the central electron gun in order to weaken horizontal deflection magnetic field acting on the central beam, whereby a portion of the horizontal deflection magnetic flux acting on the central beam is absorbed by the two magnetic pole piece plates. The vertical deflection magnetic field is almost not affected by these vertical magnetic pole piece plates. Further, two horizontal magnetic pole piece plates which are long horizontally and short vertically are so disposed as to sandwich side beams near the outlets of the side electron guns in order to weaken vertical deflection magnetic fields acting on the side beams and to intensity vertical deflection magnetic fields acting on the central beam.

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Yokohama, Japan

Kunio Ando