JPH089304A - Image display device - Google Patents

Abstract

PURPOSE:To prevent deterioration in the image quality due to ununiformed shape of picture elements by controlling a drive voltage applied to a line cathode being a beam source generating an electron beam and giving corresponding adjustment data to a memory so as to eliminate the dispersion in a beam spot to be caused. CONSTITUTION:A counter 102a uses a clock 101a being a vertical synchronizing signal as an initializing signal and counts number of clocks 101b being 11H periodic signals till another clock 101a is received again. Then a counter 102b counts number of horizontal synchronizing signal clocks 101c by using the clock 101b as an initializing signal. A memory 103 receiving the count by the counter 102a as a high-order address and the count by the counter 102b as a low-order address provides an output of an adjustment value corresponding to a scanning line. The adjustment value is given to a D/A converter 104, from which an analog signal is given to an amplifier 105 and then the voltage of the analog signal is amplified to a degree to control a drive voltage of the line cathode. Thus, a vertical diameter of a beam spot is controlled by giving the adjustment address data to the memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device used for a color television receiver, a terminal display of a computer or the like.

[0002]

2. Description of the Related Art An exploded perspective view of an image display device used in the present invention will be described with reference to FIG.

This display element has a back electrode 1, a line cathode 2 as a beam source, a beam extraction electrode 3, a beam modulation electrode 4, a focusing electrode 5, a horizontal deflection electrode 6, and a vertical deflection electrode 7 in this order from the rear to the anode side. , A screen plate 8 is arranged, and these are housed inside a vacuum container.

A linear cathode 2 as a beam source is stretched horizontally so as to generate an electron beam linearly distributed in the horizontal direction, and the linear cathodes 2 are further arranged at intervals in the vertical direction (see FIG. 3 shows only 7 of 2a to 2g). In this configuration, the line cathode spacing is 4.4 mm,
Assuming that the number of the line cathodes is 44, the line cathodes are 2a to 2s. The distance between the line cathodes cannot be freely set to a large value, and is regulated by the distance between the vertical deflection electrode 7 and the screen 8 described later. As a structure of these wire cathodes 2, an oxide cathode material is applied to the surface of a tungsten rod having a diameter of 10 to 30 μm. As will be described later, the above-mentioned line cathode is controlled so as to sequentially emit an electron beam from the upper line cathode 2a to the lower line cathode 2s for a fixed time.

The back electrode 1 not only prevents the generation of electron beams from other line cathodes but also pushes out the electron beams only toward the anode. Although the vacuum container is not shown in FIG. 5, the back electrode 1 may be used to form a structure integrated with the vacuum container.

The beam extraction electrode 3 is a conductive plate 11 having a plurality of through holes 10 which are arranged in a row in the horizontal direction facing each of the line cathodes 2a to 2s at regular intervals, and the electron beam emitted from the line cathode 2 is emitted. Is taken out through the through hole 10.

Next, the beam modulating electrode 4 is formed by the line cathodes 2a to 2s.
A long conductive plate 15 having a through hole 14 at a position facing each of them, and a plurality of horizontal conductive plates 15 are arranged in parallel in a horizontal direction at a predetermined interval. In this configuration, 222 beam-modulating-electrode conductive plates 15a to 15n are provided (only eight are shown in FIG. 5).

The beam modulating electrode 4 indicates the passing amount of each electron beam horizontally divided by the beam extracting electrode 3 as R.
PWM modulation is performed corresponding to the GB video signal. Moreover, the control is performed in synchronization with the timing of horizontal deflection described later.

The focusing electrode 5 is a conductive plate 17 having a through hole 16 at a position facing each through hole 14 provided in the beam modulating electrode 4, and focuses the electron beam.

The horizontal deflection electrode 6 is composed of a pair of comb-shaped conductive plates 18 and 18 'vertically arranged along both sides of the through hole 16 in the horizontal direction. A horizontal deflection voltage is applied. In the present configuration, a pair of electrodes 18 and 18 'are used to provide two electrodes per horizontal scanning line.
Twenty-two electron beams are simultaneously deflected in the horizontal direction, and the R, G, and B phosphors are sequentially irradiated on the screen 8 to emit light. In this configuration, the electron beam is deflected by 3 trio (that is, by 9 dots).

The vertical deflection electrode 7 is composed of a pair of comb-shaped conductive plates 19 and 19 'horizontally arranged at intermediate positions of the through holes 16 in the vertical direction. A deflection voltage is applied to deflect the electron beam in the vertical direction. In the present configuration, the electron beam generated from one line cathode by the pair of electrodes 19 and 19 'is vertically moved to 1
Deflection by one line and 484 vertically on the screen
Drawing a horizontal scan line of a book.

As described above, in this structure, the horizontal deflection electrode 6 and the vertical deflection electrode 7 are arranged in a comb shape. Further, by setting the distance to the screen 8 longer than the distance between the horizontal and vertical deflection electrodes, it becomes possible to irradiate the screen 8 with the electron beam with a small deflection amount. As a result, the deflection distortion can be reduced both horizontally and vertically.

As shown in FIG. 5, the screen 8 is formed by coating the back surface of the glass plate 21 with the phosphor 20 in a stripe shape. Although not shown, metal back and carbon are also applied. The phosphor 20 is the beam modulation electrode 4
By irradiating the electron beam passing through one of the through holes 14 in the horizontal direction to irradiate the phosphor pairs of three colors of R, G and B for 3 trio (that is, for 9 dots), It is applied in stripes in the vertical direction.

In FIG. 5, broken lines drawn on the screen 8 indicate vertical divisions corresponding to the plurality of line cathodes 2, and two-dot complex lines indicate each of the plurality of beam modulation electrodes 4. Shows the horizontal divisions displayed in correspondence with.
Fig. 4 is an enlarged view of one section divided by a broken line and two-dot complex line.
Shown in.

As shown in FIG. 4, the R, G, and B phosphors for 3 trios (that is, 9 dots) in the horizontal direction and the width for 11 lines in the vertical direction are provided. In this example, the size of one section (one unit) is 1.23 mm in the horizontal direction and 4.4 mm in the vertical direction. Note that, in FIG. 4, the vertical and horizontal dimensional ratios are different from the image actually displayed on the screen for convenience of description. Further, in the present configuration, R, G, and B phosphors for 3 trio are provided for one through hole 14 of the beam modulation electrode 4, but 1 trio, 2 trio, or 4 trio or more. It may be configured with. However, the R, G, and B video signals of 1 trio, 2 trios, or 4 trios or more are sequentially applied to the beam modulation electrode 4, and it is necessary to perform horizontal deflection in synchronization therewith.

[0016]

However, when the electron beam is vertically deflected by the above method, the vertical spot diameter of the electron beam varies (see FIG. 4), the uniformity of the display screen is impaired, and the image quality deteriorates. Had the problem of doing.

In order to solve the above problems, the image display device of the present invention has a circuit for controlling the line cathode drive voltage or the beam modulation electrode voltage, and is simultaneously deflected horizontally in one horizontal scanning line. A means for controlling the vertical diameters of the plurality of beam spots is provided.

[0018]

First, in order to solve the above-mentioned problems, the first means of the present invention is to control the driving voltage of the above-mentioned line cathode as a beam source for generating an electron beam, thereby It has means for controlling the vertical diameter in units of scanning lines.

In order to solve the above-mentioned problems, the second means of the present invention is to control the drive voltage of the above-mentioned line cathode as a beam source for generating an electron beam so that the vertical diameter of the beam spot falls within the vertical section. It has a means for controlling in scanning line units.

Further, in order to solve the above-mentioned problems, the third means of the present invention is to control the voltage of the beam modulating electrode for modulating the electron beam amount in each horizontal section by dividing the beam spot into a beam spot. It has means for controlling the vertical diameter of each horizontal section.

In order to solve the above-mentioned problems, a fourth means of the present invention is to control the voltage of the beam modulating electrode for modulating the electron beam amount in each horizontal section by dividing the electron beam quantity in the horizontal direction. And a means for controlling the vertical diameter of each pixel.

[0022]

According to the present invention, it is possible to eliminate the variation in the vertical diameter of the beam spot caused by the difference in the incident angle of the electron beam phosphor at the time of vertical deflection, and prevent the deterioration of the image quality due to the nonuniform pixel shape.

[0023]

【Example】

(Example 1) Example 1 of the present invention (corresponding to claim 1)
The drive voltage control circuit for the line cathode (see 2a to 2g in FIG. 5) in FIG. 5 will be described with reference to FIG.

In FIG. 1, 101a is a vertical synchronizing signal,
101b is an 11 horizontal cycle signal, 101c is a horizontal sync signal, 102a is a counter that initializes with a vertical sync signal 101a and counts with 11 horizontal cycle signals 101b, and 102b is 11
A counter that initializes with the horizontal cycle signal 101b and counts with the horizontal synchronizing signal, 103 is a memory whose address is the output of the counters 102a and 102b, and 104 is a memory 103.
Is a D / A converter for D / A converting the data output of the device, 105 is an amplifier for amplifying the output of the D / A converter, and 106 is a drive voltage for the line cathode.

The operation of the drive voltage control circuit for the line cathode constructed as above will be described. The counter 102a uses the clock 101a, which is a vertical synchronization signal, as an initialization signal, and counts the clock 101b, which is an 11-horizontal period cycle signal, until the clock 101a is input again. Therefore, in this example, the counter 102a counts the number of line cathodes each time the clock 101a is input.

The counter 102b counts the horizontal synchronizing signal clock 101c using the clock 101b as an initialization signal. Therefore, in this example, the counter 102b uses the clock 10
Every time 1b is input, the number of scanning lines displayed by one line cathode (11 in this example) is counted.

The count value of the counter 102a is set to the upper address,
The adjusted value corresponding to the scanning line is output by supplying the count value of the counter 102b as the lower address to the memory 103. The adjustment value obtained in the memory 103 is input to the D / A converter 104.

The analog signal D / A converted by the D / A converter 104 is amplified by the amplifier 105 to a voltage suitable for controlling the drive voltage of the line cathode.

By inputting the corresponding adjustment data to the memory by the above method, the vertical diameter of the beam spot can be controlled by controlling the driving voltage of the line cathode for each scanning line. The time chart of the clock used is shown in FIG.

(Embodiment 2) Further, by omitting the counter 102a and inserting clocks 101b and 101c into the counter 102b, driving of the line cathode in the second embodiment of the present invention (corresponding to claim 2). A voltage control circuit can be configured, and it becomes possible to control the vertical diameter of the beam spot for each scanning line in the vertical section.

(Embodiment 3) A voltage control circuit for a beam modulating electrode (see electrode 4 in FIG. 5) in a third embodiment (corresponding to claim 3) of the present invention will be described with reference to FIG.

In FIG. 1, a1 to a222 are counters which are initialized with a vertical synchronizing signal 101a and count with a horizontal synchronizing signal, b1 to b222 are memories whose address inputs are counters a1 to a222, and c1 to c222 are memories b.
1 to b222 are D / A converters for D / A converting the data outputs, d1 to d222 are amplifiers for amplifying the outputs of the D / A converters c1 to c222, and e1 to e222 are control voltages for controlling the beam modulation electrodes. is there.

The operation of the voltage control circuit for the beam modulation electrode according to the third embodiment of the present invention constructed as above will be described.

The counters a1 to a222 use the clock 101a which is a vertical synchronizing signal as an initialization signal and count the clock 101c which is a horizontal synchronizing signal until the clock 101a is input again. Therefore, the counters a1 to a22
2 counts the number of scanning lines each time the clock 101c is input. The memories b1 to b222 receive the count values of the counters a1 to a222 as addresses and output corresponding adjustment values.

The adjustment value is input to the D / A converters c1 to c222. The analog signals D / A converted by the D / A converters c1 to c222 are voltages e1 to e222 suitable for controlling the beam modulation electrode voltage by the amplifiers d1 to d222.
Is amplified.

By inputting the corresponding adjustment data to the memory by the above method, the vertical diameter of the beam spot can be controlled by the control voltage of the beam modulation electrode in units of one horizontal section, that is, in units of scanning lines.

A time chart of the clock used in this example is shown in FIG. (Fourth Embodiment) Further, by changing the clock 101c to a signal having a period of 1/9 of the horizontal synchronizing signal (the length of the period is inversely proportional to the number of pixels in one horizontal section), the fourth aspect of the present invention
The voltage control circuit for the beam modulation electrode in the embodiment (corresponding to claim 4) can be configured, and the vertical diameter of the beam spot can be controlled in a unit of one pixel.

[0038]

According to the image display device of the present invention, (1) by scanning line unit, (2) by controlling the driving voltage of the line cathode by scanning line unit within the vertical section, and (3) by horizontal section. (4) By controlling the voltage of the beam modulation electrode for each pixel, it is possible to realize a highly uniform image display without deviation of the vertical diameter of the beam spot on the screen during vertical deflection of the electron beam. , Its implementation effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive voltage control circuit for a line cathode according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a voltage control circuit for a beam modulation electrode according to a third embodiment of the present invention.

FIG. 3 is a diagram showing a time chart of a clock used in each embodiment of the present invention.

FIG. 4 is an enlarged view of a phosphor screen of an image display device and a change diagram of a vertical diameter of an electron beam due to vertical deflection.

FIG. 5 is an exploded perspective view of an image display device used in the present invention.

[Explanation of symbols]

 101a Vertical synchronization signal 101b 11H periodic signal 101c Horizontal synchronization signal 102a Counter 102b Counter 103 Memory 104 D / A converter 105 Amplifier 106 Wire cathode drive voltage a1 to a222 Counter b1 to b222 Memory c1 to c222 D / A converter d1-d222 amplifier e1-e222 control voltage

Claims (4)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam, and a line as a beam source for generating an electron beam in each vertical section obtained by vertically dividing the screen on the screen. A cathode, a back electrode and a beam extraction electrode for controlling the total amount of electron beams, a beam modulation electrode PWM-modulated for each horizontal section obtained by horizontally dividing the electron beam quantity, and an electron beam for each vertical section. In an image display device having a pair or a plurality of horizontal deflection electrodes for simultaneously deflecting in the horizontal direction and a pair or a plurality of vertical deflection electrodes for simultaneously deflecting the electron beam for each vertical section in the vertical direction, A means for controlling the vertical diameter of the beam spot in units of scanning lines by controlling the drive voltage of the above-mentioned line cathode as a beam source to be generated Image display device. 2. A screen coated with a phosphor that emits light when irradiated with an electron beam, and a line as a beam source for generating an electron beam for each vertical section obtained by vertically dividing the screen on the screen. A cathode, a back electrode and a beam extraction electrode for controlling the total amount of electron beams, a beam modulation electrode PWM-modulated for each horizontal section obtained by horizontally dividing the electron beam quantity, and an electron beam for each vertical section. In an image display device having a pair or a plurality of horizontal deflection electrodes for simultaneously deflecting in the horizontal direction and a pair or a plurality of vertical deflection electrodes for simultaneously deflecting the electron beam for each vertical section in the vertical direction, By controlling the driving voltage of the above-mentioned line cathode as a beam source to be generated, there is provided means for controlling the vertical diameter of the beam spot in units of scanning lines in the vertical section. An image display device characterized by the following. 3. A screen coated with a phosphor that emits light when irradiated with an electron beam, and a line as a beam source for generating an electron beam for each vertical section obtained by vertically dividing the screen on the screen. A cathode, a back electrode and a beam extraction electrode for controlling the total amount of electron beams, a beam modulation electrode PWM-modulated for each horizontal section obtained by horizontally dividing the electron beam quantity, and an electron beam for each vertical section. In an image display device having a pair or a plurality of horizontal deflection electrodes for simultaneously deflecting in the horizontal direction and a pair or a plurality of vertical deflection electrodes for simultaneously deflecting the electron beam for each vertical section in the vertical direction, By controlling the voltage of the beam modulation electrode that modulates in each horizontal section, the vertical diameter of the beam spot is adjusted in each horizontal section. An image display device having means for controlling. 4. A screen coated with a phosphor that emits light when irradiated with an electron beam, and a line as a beam source for generating an electron beam for each vertical section obtained by vertically dividing the screen on the screen. A cathode, a back electrode and a beam extraction electrode for controlling the total amount of electron beams, a beam modulation electrode PWM-modulated for each horizontal section obtained by horizontally dividing the electron beam quantity, and an electron beam for each vertical section. In an image display device having a pair or a plurality of horizontal deflection electrodes for simultaneously deflecting in the horizontal direction and a pair or a plurality of vertical deflection electrodes for simultaneously deflecting the electron beam for each vertical section in the vertical direction, The vertical diameter of the beam spot is controlled for each pixel by controlling the voltage of the beam modulation electrode that modulates for each horizontal division An image display device comprising means for performing.