Matsushita Electric Industrial Co., Ltd.

Shizuo Inohara

Keisuke Yamamoto

Mitsuya Masuda

Minoru Ueda

Sadahiro Iyehara

Mitsuhiro Kasahara

Jumpei Hashiguchi

Yoshio Yasumoto

Mitsuhiro Mori

Luminous gradations are displayed to display luminous half tones. This is accomplished by superposing in time wise fashion a plurality of binary images, in which the binary images are individually assigned with a weight according to respective luminous level so that an absolute value of difference (&ldquo;primary difference&rdquo;) of the weights that are assigned to each of the adjoining binary images becomes equal to or less than 6% of a total number of luminous gradations that are displayed by superposing the binary images, when the binary images are arranged in an ascending order.

Image display method

A flat CRT type color image display apparatus comprises a number of horizontally disposed parallel line cathodes, vertical and horizontal deflection means and electron beams control means, wherein a clock pulse signal is produced by frequency-multiplying a pulse signal which is synchronized with color sub-carrier of the color TV signal, chrominance signal is A/D converted using the clock signal, therewith producing a PWM signal with which electron beams are controlled.

Color image display apparatus

The video image display apparatus of flat tube type comprising

Image display apparatus

A flat CRT type image display apparatus comprises a number of horizontally disposed parallel line cathodes and vertical and horizontal deflection means, and electron beams control means, and the deflection means includes digital memory means storing data for deflection signals, address counter means for producing address signal to read out the digital memory means, D/A converters for converting read out data to produce deflection signals and also a microcomputer for setting and adjusting data in the digital memory means.

A flat type color display apparatus includes a phosphor screen and 15 horizontal line cathodes activated in turn from the top one to the bottom one. An electron beam control means and a beam deflection means are provided. Each horizontal line cathode emits a horizontal sheet-shaped electron beam which is vertically deflected in 16 steps, and is divided into 320 rod-shaped electron beams by 320 vertically oblong slits and individually controlled of its intensity by 320 beam-control electrodes. The rod-shaped electron beams are horizontally deflected each selectively impinging R, G and B vertical phosphor stripes in turn. In the operation circuit, R, G and B video signals are sampled and held in R, G and B parts of 320 sample-hold circuits, and stored at one time in 320 memories for respective colors, and time sharingly applied to the respective beam-control electrodes. A color video image is thereby displayed of 240 lines each having 320 picture elements.

A video image display apparatus of the flat tube and multi line cathode type of the present invention includes a phosphor screen, and a predetermined number (e.g. 15) of line cathodes for in-turn emitting a predetermined number of horizontal rows of electron beams. Each row has a second predetermined number (e.g. 320) of rod shaped electron beams for together producing one horizontal line of image on the phosphor screen. A vertical deflection means is provided for vertical deflection of the electron beams in turn at one vertically divided segment corresponding to one of the horizontal rows by means of a vertical deflection signal, e.g. a step wave having a saw-tooth wave envelope. The envelope is adjusted so as to be expanded or compressed or level changed, thereby eliminating any undesirable black horizontal band on the screen due to non-uniformity of electrode construction. A uniform raster is thereby obtainable.

A flat type display apparatus includes an electron beam source for emitting a row of a large number of electron beams, and a phosphor screen having a phosphor layer which emits light in response to impingement by the electron beams. An electron beam convergence means is provided and an electrostatic deflection means for deflecting the electron beams prior to impingement on the phosphor screen. An electron beam controlling means has a number of electron beam controlling electrodes for individually controlling the current of the electron beams to control light emissions from the phosphor screen. A pulse width modulation circuit feeds electron control signals of a constant voltage and pulse-width modulated by video signal information to be displayed. Light emission control without changing converging conditions of electrostatic lenses is thus obtained so that a good linearity between the video signals and the electron beams is obtained.

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Toyonaka, Japan

Shizuo Inohara