JPH04196989A - Method of controlling flat plate type image display device - Google Patents

Abstract

PURPOSE:To improve the brightness of a flat plate type image display device and to simultaneously prolong its life by controlling this device in such a manner that the product of the average electron beam current arriving at a fluorescent surface and the time ratio to allow the passage of the electron beam by electron beam control electrodes is constant and the above-mentioned time ratio is minimized. CONSTITUTION:The flat plate type image display device is so controlled that product of the average electron beam current arriving at the fluorescent surface and the time ratio to allow the passage of the electron beam by the electron beam control electrodes is constant and the above-mentioned time ratio is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of controlling a flat panel image display device that displays characters, images, and the like.

Conventional technology Ganto Toyama has already developed a flat panel type that can display characters, images, etc. by extracting electron beams from multiple linear hot cathodes and colliding the electron beams controlled by electron beam control electrodes with phosphors. We have proposed an image display device.

This flat panel image display device has a configuration as shown in FIG. In FIG. 3, 1 is a back electrode, and electron beams 2 are emitted from a plurality of linear hot cathodes 2a to 2d.
2 to face the front. 3 is a linear hot cathode 2a
This is an electron beam extraction electrode that extracts electrons from ~2d. This electron beam extraction electrode 3 has an electron beam 22
A through hole 12 is provided through which the through hole 12 passes. Reference numeral 4 denotes a signal electrode for applying a video signal, which is composed of a plurality of electron beam control electrodes 14 and is provided with a through hole 13 through which the electron beam 22 passes. 5 and 6 are electron beams 22
a first focusing electrode and a second focusing electrode that focus the horizontally and vertically. These focusing electrodes 5, 6 are provided with through holes 15, 16 through which the electron beam 22 passes. A horizontal deflection electrode 7 deflects the electron beam 22 in the horizontal direction of the screen, and is composed of a pair of comb-shaped electrodes 7a and 7b. A slot 18 through which the electron beam 22 passes is formed between these comb-shaped electrodes 7a and 7b.

A vertical deflection electrode 8 deflects the electron beam 22 in the vertical direction of the screen, and is composed of a pair of comb-shaped electrodes 8a+8b. A slot 20 through which the electron beam 22 passes is formed between the comb-shaped electrodes 8 a + 8 b.

10 is a front glass container, and the inner surface of this front glass container 10 consists of three color phosphor layers of red, green, and blue, a black stripe layer provided between them, and a metal back layer provided behind them. A screen 23 is provided. Engineering 1
is a metal plate that serves as a transfer device, and is combined with the front glass container 10 to form a vacuum container.

In a flat panel image display device having such a configuration, the amount of electrons emitted also depends on the performance of the linear hot cathodes 2a to 2d.
It is approximately determined by the positive voltage applied to the electron beam extraction electrode 3 and the negative voltage applied to the back electrode 1. In addition, the electron beam current reaching the phosphor screen is
Among the electron beams 22 emitted from a to 2d and passing through the electron beam extraction electrode 3, only the current of the electron beam 22 is controlled by the electron beam control electrode 14. This flat panel image display device uses PWM modulation to control the electron beam 22, and the amount of electron beam passing is controlled by the pulse width. Therefore, the brightness of conventional flat panel image display devices depended on the pulse width.

Problems to be Solved by the Invention Incidentally, the brightness of a flat panel image display device depends on the pulse width, that is, the electron beam current, and the anode voltage, as described above, so in order to increase the brightness, it is necessary to increase both. good. However, in order to take advantage of the characteristics of the flat plate type, it is necessary to shorten the travel distance of the electron beam, and because the electrode spacing cannot be made large, the anode voltage cannot be increased extremely, and the pulse width must be increased to increase the beam current. However, in this case, there were problems in that even if the beam current was increased, the brightness did not improve much and the phosphor deteriorated early.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for controlling a flat panel image display device that can obtain sufficient brightness without prematurely deteriorating the phosphors.

Means for Solving the Problems In order to solve the above problems, a method for controlling a flat panel image display device according to the present invention includes a plurality of linear hot cathodes, and an electron beam extraction electrode for extracting electrons from the linear hot cathodes. , a back electrode provided opposite to the electron beam extraction electrode with the linear hot cathode in between, an electron beam control electrode for controlling the amount of electron beam passing through, and a deflection electrode for deflecting the electron beam horizontally and vertically. and a phosphor screen that emits light upon collision with an electron beam, wherein the product of the average electron beam current reaching the phosphor screen and the proportion of time for the electron beam to pass through the electron beam control electrode is constant. , and the time ratio is controlled so as to be minimized.

Effects With the above configuration, deterioration of the phosphor can be suppressed and brightness can be efficiently improved, and reduction in the life of the phosphor can also be suppressed and the life of the phosphor can be improved.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. Note that the structure of the flat panel image display device used in the present invention is the same as that shown in FIG. 4, so a description of the structure will be omitted.

The present invention provides a flat panel image display device shown in FIG. 4, in which the product of the average electron beam current reaching the phosphor screen and the time ratio for passing the electron beam by the electron beam control electrode 14 is constant, and the time ratio is It is controlled so that it is minimized.

FIG. 1(a) is a characteristic diagram showing changes when the voltage applied to the electron beam extraction electrode 3 is plotted on the horizontal axis and the anode average current is plotted on the vertical axis. At this time, the application time of the pulse applied to one phosphor of the electron beam control electrode 14 was set to the maximum (100% dat3') of 10 μs. 1st
As can be seen from Figure (a), the electron beam extraction electrode 3
The average anode current increases at a constant rate as the voltage applied to the anode increases.

In FIG. 1(b), the horizontal axis represents the application time ratio (pulse width) of the pulse applied to one phosphor of the electron beam control electrode 14, and the vertical axis represents the anode average current (O mark). FIG. 3 is a characteristic diagram showing changes in brightness (indicated by Δ) in the case of FIG. For example, when the emission current from the linear hot cathodes 2a to 2d is 10 mA,
When the electron beam current passing through the electron beam extraction electrode 3 is 200 μA, the application time of the pulse applied to one phosphor of the electron beam control electrode 14 is the maximum (100% du
ty), the anode average current is 200μs.
A, and as shown in FIG. 1(b), as the pulse application time becomes shorter, the anode average current also decreases, but the decrease in brightness is not so significant. this is,
This shows that the longer the pulse application time, the more deterioration of the phosphor occurs. Therefore, the flat panel image display device is controlled so that the product of the average electron beam current reaching the phosphor screen and the time ratio of the electron beam passing through the electron beam control electrode 14 is constant, and this time ratio is minimized. By doing so, the brightness can be efficiently improved.

In addition, Figure 2 shows the life test results when the product of the average anode current and the pulse application time is the same.
The solid line part shows the case where the pulse application time ratio is 100%, and the dotted line part shows the case where the pulse application time ratio is 50%. As can be seen from Figure 2, while decreasing the pulse application time ratio,
In addition, by increasing the voltage applied to the electron beam extraction electrode 3 and increasing the number of electron beams extracted from the linear hot cathodes 2a to 2d, the life of the phosphor can be extended.

Effects of the Invention As described above, according to the present invention, in a flat panel image display device, the product of the average electron beam current reaching the phosphor screen and the time ratio of the electron beam passing through the electron beam control electrode is constant; By controlling the time ratio to be the minimum, it is possible to simultaneously improve the brightness and extend the life of the flat panel image display device.

[Brief explanation of the drawing]

FIG. 1(a) is a characteristic diagram showing the relationship between the voltage applied to the electron beam extraction electrode and the average anode current in the flat panel image display device according to the embodiment of the present invention, and FIG. 1(b)
2 is a characteristic diagram showing the relationship between the application time ratio, the average anode current, and the brightness in the flat panel image display device, and FIG. 2 shows the relationship between the fluorescent panel ON time and the rate of decrease in brightness in the same flat panel image display device. The characteristic diagram and FIG. 3 are exploded perspective views of the flat panel image display device. 1@... Back electrode, 2a to 2d... Linear hot cathode, 3
* * *Electron beam extraction electrode, No. 4110 signal electrode, 5.6-...Focusing electrode, 7.9.Horizontal deflection electrode, 8
...Vertical deflection electrode, 14...Electron beam control electrode,
22...Electron beam, 23...Fist screen (phosphor screen). i east(mu m(pi V change 42″-practice → year″:'i- trade-・Winten)

Claims (1)

[Claims] 1. A plurality of linear hot cathodes, an electron beam extraction electrode for extracting electrons from the linear hot cathode, a back electrode provided opposite to the electron beam extraction electrode with the linear hot cathode in between, and an electron beam extraction electrode. In a flat panel image display device having an electron beam control electrode that controls the amount of beam passing through, a deflection electrode that deflects the electron beam horizontally and vertically, and a phosphor screen that emits light when the electron beam collides with the electron beam, the phosphor screen is reached. A control method for a flat panel image display device, wherein the product of the average electron beam current and the time ratio of the electron beam passing through the electron beam control electrode is constant, and the time ratio is minimized.