JPH02239550A - Plane type image display device - Google Patents

Abstract

PURPOSE:To increase the brightness without increasing the accelerating voltage and/or current of an electron beam by performing parallel driving of electron beam modulating electrodes group by group corresponding to a certain plural number of wire hot cathodes. CONSTITUTION:Electron beam modulating electrodes corresponding to wire hot cathodes 1a, 1b, ...1n and 1a', 1b',...1n' are divided in electrical terms into No.1 group 13 and No.2 group 13', so that electron beams emitted from those two groups of wire hot cathodes 1a, 1b,...1n and 1a', 1b',...1n' are modulated perfectly independently. Accordingly electron beams are emitted at all times from two wire hot cathodes 1, and further, driving the cathodes 1 two by two enables making the horizontal deflecting time twice of where driven one by one by.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flat panel image display device used in color television receivers, computer terminal displays, and the like.

Conventional technology Conventionally, as a flat panel image display device, Japanese Patent Application Laid-open No. 54-143
The configurations described in Publication No. 063, Publication No. 55-33734, etc. have been proposed. This flat panel image display device obtains a band-shaped electron beam using an electron source composed of a linear hot cathode and deflection electrodes facing each other, applies a potential difference to the deflection electrodes, performs, for example, vertical scanning, and then These electron beams are deflected in the horizontal direction by a horizontal deflection electrode, and the electron beams cause multiple sets of phosphors formed on a transparent substrate to emit light, thereby displaying images, characters, etc. on the screen. I'm letting you do it. Hereinafter, a typical configuration of the above-mentioned conventional flat panel image display device will be described with reference to the drawings.

FIG. 4 is a perspective view of the main parts of a conventional flat panel image display device.

In Fig. 4, 1 is a filament hot cathode with a diameter of 10~
A few micrometers of oxide electron emitting material is added to a tungsten wire of several micrometers.
It is coated in a thickness of m to several tens of μm, and a predetermined voltage is applied to both ends and heated to 600 to 800° C. to generate uniform electrons from the oxide electron emitting material. As shown in FIG. 5, these linear hot cathodes 1 are heated in synchronization with a vertical synchronization signal (IV) by turning on and off a direct current voltage Ek (y), and when turned off, electrons are transferred to the linear hot cathode 1. A method is adopted in which a pulsed potential Ekp having a width necessary for radiation from the hot cathode 1 is applied. One frame of a television image is formed by sequentially applying the pulse waveforms shown in FIG. 5 to the plurality of linear hot cathodes 1 while shifting the timing. Reference numeral 2 denotes a back electrode, and a metal film is formed on a metal plate or the inner surface of the envelope (not shown) of the image display device by means of vacuum evaporation, sputtering, etc.
Alternatively, it is formed by forming a conductive film such as a transparent conductive film,
Electronic beams generated by heating the filament hot cathode 1
=-Push the bar 11 in a predetermined direction. Reference numeral 3 denotes two electrodes for drawing out the electron beam, and a through hole 3a for passing the electron beam 1 corresponds to the linear hot cathode 1, through which the generated electrons can be drawn out. It is provided. The shape, size, number, etc. of the through holes 3a are determined by the number of electron beams required, the magnitude of the electron beam current, etc. Reference numeral 4 denotes a vertical deflection electrode, and conductive electrodes 4a are formed on both surfaces of a substrate made of an insulator by means of vacuum evaporation, screen printing, etc., and deflect the electron beam 11 in a direction perpendicular to the screen. A modulation electrode 5 controls the division of the electron beam 11 in the horizontal direction and the amount of the electron beam 11. 6 is a shield electrode, which shields the influence of the front and rear electrodes. 7 is a horizontal deflection electrode;
It is formed into a comb shape that is electrically divided into two parts, and horizontally deflects the electron beam 11. 8 is an electrode that accelerates the electron beam;
9 is a transparent substrate (glass), which is generally used as a face plate which is the envelope of an image display device, and on the vacuum side of the transparent substrate is a phosphor layer and a metal bank layer made of a thin aluminum film. A light emitting section 10 is formed. Usually, the metal back layer has a high voltage (5
~20 kV) is applied.

The flat panel image display device uses a plurality of linear hot cathodes 1, deflects an electron beam 11 vertically and horizontally for each beam, and displays one image on a fluorescent surface. It has the feature that a thin display device with high brightness and high resolution can be obtained with a simple configuration.

Problems to be Solved by the Invention However, in the conventional flat panel image display device as described above, when increasing the brightness with the same screen size, or when trying to increase the screen size and keep the brightness the same, increases the accelerating voltage of the electron beam 11, or
It is necessary to increase the electron beam current. If the accelerating voltage of the electron beam is increased, the deflection sensitivity of the electron beam decreases, so it is necessary to increase the deflection voltage or narrow the deflection distance. The relationship between acceleration voltage and deflection voltage is one-to-one, so if the acceleration voltage is increased by 50 degrees to increase brightness, the deflection voltage must also be increased by 50 degrees, which increases the burden on the circuit elements. In some cases, it may not be possible. Furthermore, if the deflection voltage is not increased, the deflection distance will become narrower, so it will be necessary to increase the number of linear hot cathodes 1, which will lead to a significant increase in power consumption and cost.

In order to increase the screen size and compensate for the decrease in brightness by increasing the electron beam current, it is necessary to significantly increase the electron beam current, considering that brightness is inversely proportional to the image display area. As the electron beam current increases, the beam spot diameter increases, leading to a decrease in resolution or, in the case of color display, a decrease in color purity.

The present invention solves the problems of the prior art as described above, without increasing the accelerating voltage of the electron beam, and
It is an object of the present invention to provide a flat panel image display device in which brightness can be improved without significantly increasing electron beam current.

Means for Solving the Problems In order to achieve the above object, the technical solution of the present invention is as follows:
For multiple filament hot cathodes arranged in a vacuum envelope,
An electron beam modulation electrode is disposed on the opposite side of the fluorescent surface, and this electron beam modulation electrode is electrically divided in the length direction of the linear hot cathode, and is divided into sections for each of the plurality of linear hot cathodes. It is electrically divided in a direction orthogonal to the above-mentioned dividing direction.

Then, the electron beam modulation electrode divided into the plurality of linear hot cathodes is driven so that parallel K electron beams are emitted sequentially within the same divided section, and parallel K electron beams are radiated in different divided sections.

Furthermore, crosstalk prevention electrodes are provided adjacent to both sides of the linear hot cathode of the electron beam modulation electrode in the length direction.

A predetermined voltage is applied to the crosstalk prevention electrode.

Therefore, according to the present invention, by driving in parallel each electron beam modulation electrode group divided by a plurality of filament hot cathodes, two or more light emitting electron beams can be emitted at a certain moment. L, Moreover, it becomes possible to more than double the emission time of the electron beam spot, and it is possible to significantly improve the brightness.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described.

FIG. 1 is a perspective view of essential parts of a flat panel image display device according to a first embodiment of the present invention.

In FIG. 1, 1a, Ib, 1a. '1b',・
. . . denotes a plurality of linear hot cathodes, and 12 denotes an insulating substrate, which may also be used as a part of the vacuum envelope. 13a, 13b, 13
C, 13d,..., 13a', 13b', 13C'
, 13d', . . . are electron beam modulation electrodes, and the linear hot cathodes 1a, 1b, Xa/, 1b', .
... is arranged on the insulating substrate 12 on the opposite side to the fluorescent surface.

These electron beam modulation electrodes 13a, 13b, 13C, 13
d..., 13a', 13b', 13C', 13d',
... are linear hot cathodes 1a, 1b, 1a', 1b' -
+- is electrically divided at a predetermined pitch in the length direction, and a plurality of linear hot cathodes 1a, 1b and 1a/
The first electron beam modulation electrode group 13 and the second electron beam modulation electrode group 13' are electrically divided at a predetermined pitch in a direction orthogonal to the dividing direction every lb/. 3 is an electron beam extraction electrode having a through hole 3a at a position facing the linear hot cathodes 1a, 1b, 1a/I l+/ .,, 4 is each linear hot cathode 1a, 1b, 1a/1
b/ , , , are vertical deflection electrodes arranged facing each other, and these electron beam extraction electrodes 3 and vertical deflection electrodes 4
From above to the top of the screen are the conventional modulation electrode 5, shield electrode 6, horizontal deflection electrode 7, and electron beam accelerating electrode 8 shown in FIG.
, a light emitting section 10 is provided, but illustration thereof is omitted since they overlap.

Each of the above striated hot cathodes 1a, 1b, 1 a/ 1 b/
... is a tungsten wire with a diameter of about 10 to 50 μm, with an oxide electron emitting material on the surface of several μm to several tens of μm.
When heated, a uniform electron beam is emitted from the oxide electron emitting material. The amount of electron beam is the linear hot cathode 1a, lb la
'lb' - (2) When the temperature is constant, the maximum value is determined by the voltage applied to the electron beam extraction electrode 3, and the first and second electron beam modulations are performed between the maximum value and zero. It is controlled by the magnitude of the voltage applied to the electrode groups 13 and 13' or the pulse width of the voltage waveform. The first and second electron beam modulation electrode groups 13 and 13' are made of a conductive film, and are linear hot cathodes 1a, 1b, 1a', lb'
-(7) The shorter the distance 1i1m, the more
In order to control the amount of electron beam, the modulation voltage required for K may be small, but it is difficult to make it extremely short due to mechanical accuracy, and it is 0.1 to 0. 2rrrn is a reasonable distance. Each modulating electrode 13a, 13b, 13C, 13d of the first and second electron beam modulating electrode groups 13 and 13' -...
13a', 13b', 13C'13d'・
... is each through hole 3a of the electron beam extraction t-pole 3,
There is a 1:1 correspondence, and the amount of electron beam passing through the through hole 3a is the same as that between the first and second electron beam modulation electrode groups 13 and I3.
' will be controlled by '.

In FIG. 1, first and second electron beam modulation electrode groups 13,
13', two linear hot cathodes 1a, 1b and 1a, respectively.
Although only 'lb' is shown in the figure, the present invention is not limited to this, and FIG.
3.n each in the second electron beam modulation electrode group 13'
The timing of pulse voltage waveforms sequentially applied to the linear hot cathode 1 when a real linear hot cathode 1 is present is shown.

During the first horizontal deflection time (IH), the filament hot cathode 1a and x
The linear hot cathodes 1a, la' l are arranged so that electron beams are simultaneously emitted from the linear hot cathodes 1b and lb' during the next horizontal deflection time.
A pulse voltage is applied to b and lb', and finally, electron beams are emitted simultaneously from the linear hot cathodes In and 1n' [the vertical synchronization period ends]. String hot cathode 1 a. 1 b, -I
Since the electron beam modulation electrodes corresponding to n and 1a'lb'...1 nl are electrically divided into the first electron beam modulation electrode group 13 and the second electron beam modulation electrode group 13', Each filament hot cathode 1a, 1b,...1
The electron beams emitted from n and 1a/1b', . . . 1 n/ are modulated completely independently. Therefore, the electron beam is always emitted from the two filament hot cathodes 1, and by driving two filament hot cathodes 1 at a time, the horizontal deflection time is reduced by driving one at a time. It will double.

Next, a second embodiment of the present invention will be described.

FIG. 3 is a perspective view of essential parts of a flat panel image display device according to a second embodiment of the present invention.

In this embodiment, as shown in FIG. 3, electron beam modulation electrodes 13a, 13b, .
b'-13 1' striated hot cathode 1a, 1b, 1 a/
Electrodes 14 for crosstalk prevention, which are divided into approximately the same size as the electron beam modulation electrodes, are provided adjacent to both sides of the electron beam modulation electrode in the length direction.The other configuration is as shown in FIG. Since it is exactly the same as the first embodiment shown, the explanation thereof will be omitted, and the crosstalk prevention electrode 1 will be described below.
The operation No. 4 will be explained.

Electron beam modulation electrodes 1.3a, 13b, 13n and 1
3a'13b'...130' exist adjacent to each other, for example, the influence of the modulation signal of the electron beam modulation electrode 13b may affect the electron beam modulation electrode 13a or 13C.
Therefore, it may not always be possible to accurately control the amount of electron beam, and this phenomenon is called crosstalk. It is possible to prevent the effects of crosstalk by increasing the distance between adjacent electron beam modulation electrodes, but in this case, the distance between the electron beam modulation electrodes also increases, which increases the horizontal deflection distance and Failure to increase the amount of beam will lead to a decrease in brightness. Therefore, as described above, the crosstalk prevention electrode 14 is connected to the electron beam modulation electrodes 13a, 13b, -13n and 13a', 13b'.
-131', and the voltage of all the crosstalk prevention electrodes 14 is connected to the linear hot cathodes 1a, 1b, 1a/
The voltage V o is such that no electrons are emitted from the portion corresponding to the crosstalk prevention electrode 14 at t b'.
By setting ff, it is possible to prevent crosstalk from occurring even if the distance between adjacent electron beam modulation electrodes is close.

Although FIG. 3 shows the case where the crosstalk prevention electrode 14 is electrically divided like the electron beam modulation electrode group 13, 13', the effect is exactly the same even if it is not divided. Just choose the one that is convenient for production.

In each of the above embodiments, the electron beam modulation electrode groups are 13 and 13.
' is shown for the case where it is divided into upper and lower halves, but it is divided into 3, 4
It is also possible to divide the display, and the brightness increases depending on the number of divisions.

Effects of the Invention As described above, according to the present invention, by driving in parallel each group of electron beam modulation electrodes divided into a plurality of linear hot cathodes, two electron beams are emitted at a certain moment. In addition, it is possible to more than double the emission time of the electron beam spot, and improve the brightness without increasing the acceleration voltage of the electron beam or significantly increasing the electron beam current. I can do it.

Furthermore, by providing crosstalk prevention electrodes, it is possible to prevent crosstalk from occurring even if the distance between the electron beam modulation electrodes is close.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts of a flat panel image display device according to a first embodiment of the present invention, FIG. 2 is a timing chart of driving waveforms of a linear hot cathode, and FIG. FIG. 4 is a perspective view of a main part of a flat panel image display device according to an embodiment of the present invention, FIG. 4 is a perspective view of a conventional flat panel image display device, and FIG. 5 is a voltage waveform diagram for driving a linear hot cathode. 1a, 1b, 1 a/ 1 bl,,, linear hot cathode, 3... electron beam extraction electrode, 4... vertical deflection plate, 5... modulation electrode, 6... shield electrode, 7.・
・Horizontal deflection electrode, 8...Electron beam acceleration electrode, 10・
... Light emitting part, 13, 13'... Electron beam modulation electrode group, 14... Crosstalk prevention electrode. Name of agent: Patent attorney Shige Takashi Awano and one other person 2nd day 1V

Claims (4)

[Claims] (1) An electron beam modulation electrode is arranged on the opposite side of the fluorescent surface to a plurality of linear hot cathodes arranged in a vacuum envelope. A flat panel image display device that is electrically divided in the length direction and electrically divided in a direction orthogonal to the dividing direction for each of the plurality of linear hot cathodes. (2) A claim in which the electron beam modulating electrode is driven such that the electron beam is emitted sequentially within the same divided section of the electron beam modulating electrode divided into a plurality of linear hot cathodes, and in parallel in each different divided section. 1. The flat image display device according to 1. (3) The flat panel image display device according to claim 1 or 2, wherein crosstalk prevention electrodes are provided adjacent to both longitudinal sides of the linear hot cathode of the electron beam modulation electrode. (4) The flat panel image display device according to claim 3, wherein a predetermined voltage is applied to the crosstalk prevention electrode.