JPS59212887A - Crt display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a CRT display device that constitutes a man-machine interface for various electronic display systems and displays images such as characters, symbols, and figures.

In recent CRT display devices used for graph ink displays or kanji displays, the number of scanning lines has been increased in order to display large volumes, but the method for doing so is to fix the vertical deflection frequency to prevent flickering.
A common method is to increase the horizontal deflection frequency, and its value is also used in general video systems such as television receivers. J/ which is twice kH2
, 3; kHz I) or even higher.

Furthermore, recent electronic display systems have increasingly become composite systems that combine two or more systems, for example, a graphic display system and a general video system. Therefore, C used for these complex systems
It has become a very important condition that RT display devices can be shared between systems.

However, the required display capacity (horizontal deflection frequency) for each system is often different, and therefore, a CRT display device used in such a complex system cannot operate stably at two or more horizontal deflection frequencies. Very important.

However, since the conventional CRT display device causes a large variation in display screen size, it has been difficult to use it in common between different horizontal deflection frequencies.

It is an object of the present invention to eliminate such drawbacks and provide a CR1 display device that can be easily shared among different horizontal deflection frequencies.

In order to achieve the above object, the CR1 display device of the present invention has the following features:
In a CR1 display device that displays an image on a CRT tube surface by modulating the brightness of horizontally and vertically deflected scanning lines with a video signal, a deflection coil in a horizontal deflection circuit that controls the horizontal deflection of the scanning line; The composite inductance of a horizontal deflection coil circuit in which a linear reality adjustment coil and a size adjustment coil are connected in series is set in inverse proportion to two or more predetermined water-direction frequencies.

Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 shows an embodiment of the invention. In FIG. 1, reference number l is a horizontal deflection circuit. 1 indicates a setting device for setting the inductance of the horizontal deflection coil circuit, and this setting device 3 is designed to operate in conjunction with the horizontal synchronization signal switch 3. Thereby, the combined inductance of the horizontal deflection coil circuit is set corresponding to a predetermined horizontal deflection frequency or more.

Next, a description will be given of how the inductance of the horizontal deflection coil circuit corresponds to the horizontal deflection frequency.

Now, the horizontal deflection coil (generally a linearity adjustment coil and a size adjustment coil are connected in series with this)
The voltage applied to the horizontal deflection coil (including these coils) is V CVI .

Let the deflection coil current be [A], the inductance of the deflection coil be L (H), and the horizontal deflection frequency *'5r: fH
(Hz), the following equation generally holds.

V medium L・Engine・fH・・・・・・・・・・・・・・・・・・
・ (1) Expressing this in terms of deflection current I, ■ Medium v × □ ・・・・・・・・・・・・・・・・・・
(J) L # , fH is obtained.

Now, if we assume that the inductance L of the deflection coil changes in inverse proportion to the horizontal deflection frequency axis, the deflection current will be constant. That is, horizontal <1. , : Even if the frequency changes, the display screen size remains constant. therefore,
If the combined inductance of the horizontal deflection coil circuit in the horizontal deflection circuit can be set in inverse proportion to the horizontal deflection frequency, a CR1 display device that can be used in common between different horizontal deflection frequencies can be easily realized.

As described above, according to the present invention, it is possible to obtain a CR1 display device that can be easily shared among different horizontal deflection frequencies.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. /...Horizontal deflection circuit, Co...Inductance setting device, 3...Horizontal synchronization signal switch Patent applicant: NEC Corporation Representative, Patent attorney Yutabe Kumagai

Claims (1)

[Claims] In a CRT display device that displays an image on a CRT tube surface by modulating the brightness of horizontally and vertically deflected scanning lines with a video signal, a deflection coil in a horizontal deflection circuit that controls the horizontal deflection of the scanning line; A CRT display device characterized in that a composite inductance of a horizontal deflection coil circuit in which a linearity adjustment coil and a size adjustment coil are connected in series is set in inverse proportion to two or more predetermined horizontal deflection frequencies.