JPH0817468B2 - Image display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to generate an electron beam for each section when a screen on a screen is divided into a plurality of sections in the vertical direction, and to generate an electron beam for each section. The present invention relates to a device for deflecting a beam in a vertical direction to display a plurality of lines and display a television image as a whole.

2. Description of the Related Art Conventionally, a cathode ray tube has been mainly used as a display element for displaying a color television image, but the conventional cathode ray tube has a very long depth compared to the size of the screen, and a thin television image receiving device. It was impossible to create a machine. Moreover, although EL display devices, plasma display devices, liquid crystal display devices, etc. have recently been developed as flat plate display devices, they are all insufficient in terms of performance such as brightness, contrast and color display.

Therefore, Japanese Patent Application No. 56-20618 (Japanese Patent Application Laid-Open No. 57-13559) has been proposed to achieve a flat-panel display device using an electron beam.
No. 0), a new display device was proposed.

This is because when the screen on the screen is divided into a plurality of sections in the vertical direction, an electron beam is generated for each section, and each electron beam is deflected in the vertical direction to display a plurality of lines. However, the television image is displayed as a whole.

However, the above-mentioned image display device has a complicated structure, and it has been difficult to put it into practical use due to the high precision required in the assembly process, the high material cost, the basic performance, and the like. Therefore, the applicant of the present invention has proposed an image display device having a new structure in order to solve the above-mentioned problems by Japanese Patent Application No. 63-125284 (Japanese Patent Application Laid-Open No. 1-296543).
Issue).

This simplifies the electrode structure compared to the previous image display device,
Each electrode works very well for its own purpose and has little effect on anything else.

 The description will be briefly made below with reference to the drawings.

FIG. 3 is a basic configuration example of the image display device used in the present invention. In the figure, 1 is a rear electrode, 2 is a line cathode as a beam source (2 to 2), 3 is a beam extraction electrode, and an electron beam is guided to the front surface by the potential relationship of the above three electrodes. Reference numeral 4 is a beam flow control electrode, which is divided into a plurality of parts in the horizontal direction so that the light emission amount of each picture element can be controlled. The electron beam whose emission amount is controlled by the beam flow control electrode 4 is focused to a desired beam size by the focusing electrode 5 and is deflected in the horizontal direction and the vertical direction by the horizontal deflection electrode 6 and the vertical deflection electrode 7, respectively. The phosphor on the screen plate 8 is irradiated to form a raster. The above rasters are well arranged on the screen plate 8 by the respective control signals generated from the video signals to display one image as a whole.

However, in the above-described configuration, unlike the conventional cathode ray tube, the beam source is divided into a plurality of horizontal and vertical directions.
There is a problem that the amount of deflection changes due to the fluctuation of the high voltage applied to the above, and the seams of the above sections become conspicuous.

Hereinafter, the above-mentioned problems will be described with reference to the drawings.

FIG. 2 is a schematic view of the image display device used in the present invention as seen from the side. In FIG. 2, electrodes which are not necessary for explaining the joints of the vertical sections are omitted. In the figure, 31 is a high voltage source, which is connected to the screen plate 8. Also, the beam flow trajectory 30
B is the trajectory of the electron beam guided from the linear cathodes 2a and 2b as the beam source to the front surface, and the vertical deflection electrodes 7a and 7b
The trajectories are as shown in the figure depending on the polarities of b and c.

Now, it is assumed that the beam flow is guided to the point b at a certain brightness. When the brightness increases, that is, the beam flow increases, the current Ie flowing from the high voltage source 31 increases, and the potential of the screen plate 8 decreases by (IeR) as the product of the internal resistance R. When the potential of the screen plate 8 decreases, the velocity of the electron beam decreases, so that the deflection amount increases and the beam flow trajectories 30 a, 30
B is led to points c and a, respectively. When the high voltage varies according to the brightness as described above, the deflection amount changes, and the joints in the vertical sections become conspicuous. Therefore, some circuit proposals have been made to suppress the fluctuation of the high voltage, but the present situation is that there is no answer proposal with sufficient effect.

Therefore, in view of the above problems, the present invention provides an image display device in which the state of the joints of each section does not change depending on the brightness and a uniform raster is obtained as a whole.

Means for Solving the Problems In order to solve the above problems, the image display device of the present invention amplitude-modulates the voltage signal applied to the deflection electrode by the amount of electron beam irradiating the screen, and the state of the joint of each section is brightness. It has a structure that a uniform raster is obtained as a whole without changing by.

The present invention has the above-described structure, and by changing the joint state of each section caused by a change in the amount of electron beam applied to the screen and by compensating the deflection electrode voltage amplitude-modulated by the change in the amount of the electron beam, the It is possible to obtain a uniform raster as a whole by keeping the state of the seams of each section unchanged.

Example Hereinafter, an image display device of an example of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a deflection electrode voltage amplitude modulation circuit of an image display device according to an embodiment of the present invention.

In the figure, R11 to R23 are resistors, C11 and C12 are capacitors, TR11 to TR16 are transistors, 40 is a video signal, 41, 42,
43 shows the waveforms of the deflection input signal, the deflection output signal (+), and the deflection output signal (-), respectively.

Now, when the stepwise wave-shaped deflection input signal 41 as shown in the figure is input to the input terminal VIN, the deflection input signal 41 is converted into the capacitor C1.
2, the bias voltage is determined by the resistors R12 and R13, and current is output to the collector of the transistor TR11.

On the other hand, the video signal 40 input to the input terminal YIN is the resistor R
11 and capacitor C11 are integrated into a DC voltage,
It is input to the base of the transistor TR12. Transistor
TR12 and TR13 form a differential amplifier, which consists of resistors R18 and R18.
The base potential of the transistor TR13 that is resistance-divided by 19 is compared with the base potential of the transistor TR12,
The current output of the deflection input signal 41 output to the collector of the transistor TR11 is amplitude-modulated and current output to the collector of the transistor TR13. The above current output is resistor R17
The voltage is exchanged by the inverting amplification transistor TR14 and the current amplification transistors TR15 and TR16, and the deflection output signals 42 and 43 having different polarities are output to the output terminals VOUT (+) and VOUT (-).

Now, assuming that the average brightness of the screen becomes high, the amount of electron beams applied to the screen plate increases. Since the electron beam is an electron stream, this means that the current flowing from the high voltage source increases. In this way, the potential of the screen plate 8 becomes low and the deflection amount becomes large. However, when the above circuit is used, when the video signal 40 becomes high, the deflection output signals 42 and 43 are generated.
Both have smaller amplitudes. By adjusting the sizes of the resistors R15 and R16, it is possible to cancel the increase in the deflection amount and keep the deflection amount constant as a whole.

Although the video signal is used to amplitude-modulate the deflection output signal in the present embodiment, the beam current flowing in the screen may be directly converted into a voltage.

As described above, according to the present invention, the deflection electrode voltage amplitude modulation circuit amplitude-modulates the voltage signal applied to the deflection electrode according to the average value of the video signal, so that the deflection amount change due to the voltage fluctuation amount of the high voltage generation source can be prevented. It is possible to compensate and obtain an overall uniform raster.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a main part of an image display device in one embodiment of the present invention, FIG. 2 is a schematic view of an image display element used in the present invention as seen from the side, and FIG. 3 is used in the present invention. It is an exploded perspective view of an image display element. 1 ... Back electrode, 2 ... Line cathode, 3 ... Beam extraction electrode, 4 ... Beam flow control electrode, 5 ... Focusing electrode. 6 ...
Horizontal deflection electrode, 7 ... Vertical deflection electrode, 8 ... Screen plate, TR12, TR13 ... Differential amplification transistor, TR14 ... Inversion amplification transistor, TR15, TR16 ... Current amplification transistor.

Claims (1)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam, and an electron beam for generating an electron beam for each vertical section obtained by vertically dividing the screen on the screen into a plurality of sections. Source, separating means for separating the electron beam generated by the electron beam source in each horizontal direction into horizontal sections, and irradiating the screen with the electron beam; and a vertical direction between the electron beam and the screen. And a deflection electrode that deflects in a plurality of steps in the horizontal direction, and a horizontal electrode that controls the emission amount of each pixel on the screen of the screen by controlling the amount of irradiation of the screen with the electron beam separated for each of the horizontal sections. A beam flow control electrode divided into a plurality of directions, a focusing electrode for controlling the emission size on the phosphor surface by the electron beam in each pixel, and the electron beam source A back electrode for controlling the electron beam amount, a beam extraction electrode for controlling the total amount of the electron beam, and a deflection electrode voltage amplitude modulation circuit for amplitude-modulating the deflection voltage applied to the deflection electrode by the average value of the video signal. The deflection electrode deflects the electron beam focused by the focusing electrode to a desired beam size into each of a plurality of divided sections, and the deflection electrode voltage is converted by the deflection electrode voltage amplitude modulation circuit into a video signal of a video signal. An image display device characterized in that amplitude modulation is performed with an average value, and the deflection electrode voltage is controlled to be held constant so that the deflection width for each of the plurality of sections does not change due to a change in luminance.