JPS62221292A - Cathode-ray tube device - Google Patents

Abstract

PURPOSE:To execute an extremely precise chroma scan control with a low electric power by disposing a horizontal and vertical deflection yoke at an external part of a cathode-ray tube and an electrostatic deflection electrode which controls the chroma scan deflection of an electronic beam at an inner part. CONSTITUTION:On the outer periphery of the neck part of a bulb 1 in the cathode-ray tube, the electronic beam horizontal and vertical deflection yoke 11 is fitted, while inside the neck part of the bulb 1, a couple of the chroma scan electrostatic deflection electrodes 13 are disposed in front of an electronic gun 4. When the deflection yoke 11 horizontally deflects an electronic beam 6, a voltage is impressed at a triplet frequency from an auxiliary horizontal deflection circuit 14 to the electrostatic deflection electrode 13, whereby the electronic beam 6 is electrostatically deflected in the direction of reducing speed of the horizontal scanning and chroma-scanned. The voltage impressed on the electrostatic deflection electrode 13 at such a time can be low, and the chroma scan is controlled at high accuracy so that the induction magnetic fields of horizontal and vertical deflection yokes will not affect each other.

Description

DETAILED DESCRIPTION OF THE INVENTION 11. The present invention relates to a beam index type color shaded line tube device.

Natsuyoshi Jusue ■ The shadow mask method is the common method for reproducing color images in color cathode ray tubes, but recently the shadow mask method has become a beam index method that reproduces colors using a single electron gun housed in the color cathode ray tube. It has attracted attention due to its superior power consumption and brightness compared to the previous one, and is being put into practical use.

The principle of color reproduction using the beam index method is explained with reference to Figures 2 and 3. (1) shows the bulb of the cathode ray tube, and (2) shows the fluorescent film formed on the inner surface of the face of the bulb (1). , (3) is a metal bank layer formed on the fluorescent film (2), (4) is an electron gun housed in the neck of the bulb (1), and (5) is a metal bank layer formed on the outer periphery of the neck of the bulb (1). It is equipped with horizontal and vertical deflection yokes. Fluorescent film (2)
is a vertical striped pattern, for example, red, blue, and green striped colored fluorescent films (R), (B), (G), ultraviolet emitting striped index fluorescent IJ (UV), and non-emissive carbon stripes. It is formed by arranging and forming a large number of triblets (T) in a predetermined arrangement in a predetermined arrangement. The electron beam (
6) is irradiated onto the phosphor film (2) as a beam spot (E), and is horizontally deflected and scanned in a direction orthogonal to the phosphor stripes.

The diameter r of the beam spot (E) is the color light 1f (R
) (B) (G) are about the same width, it is about twice that of this @W, and the color amount light film (1'?) (I3)
In (G), the portion illuminated by the beam spot (E) emits light. In addition, when the index fluorescent film (1) is irradiated with Beam Subbot (E), the index fluorescence 1%
Ultraviolet light is emitted from (1), captured by an external photosensor (not shown), the position of the electron beam (6) is detected, and desired color reproduction is performed using the index signal from the photosensor.

In such a beam index type color cathode ray tube device, the horizontal deflection speed of the electron beam (6) is kept constant, and the beam spot (E) is aligned with, for example, one red phosphor film (R
), the brightness of the red bright spot emitted by red fluorescence 11t (R) is that the beam spot (E) is red fluorescence 1! (R
) is proportional to the time it takes to cross. Therefore, the beam spot (
Increasing the diameter r of E) will lengthen the time it takes for the beam spot (E) to cross the red fluorescent film (R), increasing the brightness. The degree to which the beam spot (E) is simultaneously irradiated on the blue phosphor film (B) and green phosphor film (G) increases, and the independent light emission time of red light becomes shorter, resulting in a change in the hue of the color image (
color purity) deteriorates.

Therefore, in order to maintain good hue and increase brightness, chroma scan deflection is used to modulate the scanning speed during horizontal deflection of the electron beam (6). This chroma scan deflection is performed while the beam spot (E) crosses one triplet (T).For example, the scanning speed is slowed down on the red fluorescent film (R) where the beam spot (E) is to be emitted. (R) This is a deflection method in which the light is apparently stopped at the top and accelerated when scanning other areas to increase the brightness of the red light. As shown in Figure 4, in this ROMAScan, a sub-deflection yoke (8) for Chromascan is placed around the outer periphery of the neck of the pulp (1), slightly apart from the main deflection yoke (7) for horizontal and vertical deflection. The arrangement is done as follows.

A sawtooth wave current is applied to the main deflection yoke (7) from the horizontal/vertical deflection circuit (9) based on the horizontal synchronization signal to guide and deflect the electron beam (6) in the horizontal direction, causing beam deflection.
- (E) is 1 Tribre 7) (T) At the timing when scanning, for example, the red fluorescent light 111 (R) to be emitted, an electron beam (6 ) in the direction opposite to that of the main deflection yoke (7), and the beam spot (E) is apparently stopped on the red fluorescent film (R). This is done for each triplet (T) based on the index signal and color reproduction signal, thereby increasing the brightness while optimizing the hue.

By the way, the frequency of the current flowing through the sub-deflection yoke (8) is as high as about 2.7 MIIz to 4 MHz, which is the reciprocal of the time it takes for the beam spot (E) to pass through one triplet (T). In order to obtain the magnetic field strength necessary to induce and deflect the electron beam (6) by passing a high-frequency current through the coil of the auxiliary deflection cork (8), the auxiliary horizontal deflection circuit (10) must have a large output. Therefore, the complete I of the auxiliary horizontal deflection circuit (10)
In addition, the induced magnetic fields generated by the main deflection yoke (7) and the sub-deflection yoke (8) are coaxial and mutually coupled, so the sub-deflection yoke (8) is used to reduce this mutual coupling.
7) (8) are placed a little apart, but if this is done, the position of the deflection start point of the electron beam (6) will become unstable, resulting in a decrease in focus, an increase in the beam spot diameter, and an increase in the deflection. There was a problem in that it was difficult to perform chroma scan with high accuracy because the sensitivity changed.

The present invention was proposed in view of the above-mentioned problems in color reproduction using the chroma scan method. A cathode ray tube device is provided in which horizontal and vertical deflection yokes are each provided with electrostatic deflection electrodes for controlling chroma scan deflection of an electron beam.

Electrostatic deflection electrodes for chroma scanning of electron beams perform chroma scanning control by electrostatically deflecting electron beams by applying a low voltage of several volts to several tens of volts. Chroma scan control is performed with high precision without interfering with the induced magnetic field of the yoke.

11± One embodiment of the present invention will be described with reference to the schematic plan view of FIG. 1. In the figure, the same parts as in FIG. 2 are designated by the same reference numerals, and the explanation will be omitted. (11) is the valve (1
) is a deflection yoke for horizontal and vertical deflection of the electron beam attached to the outer periphery of the neck, (12) is a horizontal and vertical deflection circuit, (1
3) (13) is the electron gun (4) inside the neck of the valve (1).
A pair of electrostatic deflection electrodes for chroma scan (14) are placed in front of the electron beam (6) by applying a voltage at triplet frequency between the electrostatic deflection electrodes (13) (13).
This is an auxiliary horizontal deflection circuit that performs chroma scanning of horizontal scanning.

The electrostatic deflection electrode (13) (13) is connected to the deflection coke (
11), a high frequency voltage is applied at the same timing as the chroma scan voltage applied to the sub-deflection yoke (8) in FIG. The electron beam (6) is electrostatically deflected in a direction that decelerates scanning, causing the electron beam (6) to undergo chroma scanning. Although the electrostatic deflection of the electron beam (6) by such an electrostatic deflection electrode (13) (13) has a small deflection angle, it serves as an auxiliary beam while the electron beam (6) scans one triplet (T). Since it is a deflection, a small deflection angle is not a problem. Further, the voltage applied to the electrostatic deflection electrode (13) (13) can be much smaller than that of the deflection yoke that deflects the electron beam (6) with an induced magnetic field, and in fact may be from several volts to several tens of volts.

According to the present invention, a small voltage is required to be applied to the electrostatic deflection electrode that performs chroma scan control of the electron beam, and therefore it is easy to realize low power consumption and IC implementation of the horizontal deflection circuit for chroma scan. be done. In addition, electrostatic deflection by the electrostatic deflection electrode has better linearity than inductive deflection, and since the electron beam deflected by the horizontal deflection yoke is electrostatically deflected, the deflection starting point of the electron beam is stabilized and precision is improved. This enables good ichromatic scan control and provides a highly accurate beam index type cathode ray tube device with excellent hue and brightness.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing an example of a cathode ray tube device according to the present invention. Fig. 2 is a schematic plan view of a general beam index type cathode ray tube device, Fig. 3 is a partially enlarged front view of a fluorescent film in the device shown in Fig. 2, and Fig. 4 is a schematic plan view of a conventional beam index type cathode ray tube device. It is a diagram. (6) −・Electron beam, (11) −・−Horizontal and vertical deflection beam, (13) −
Electrostatic deflection electrode. Figure 1 (Bane Ginpei Button Figure 2)

Claims (1)

[Claims] (1) In a beam index cathode ray tube that uses the chroma scan method to horizontally deflect the electron beam, horizontal and vertical deflection yokes are installed on the outside of the cathode ray tube, and electrostatic deflection electrodes are installed inside to control the chroma scan deflection of the electron beam. A cathode ray tube device characterized in that: