JPS6297487A - Picture display device - Google Patents

Abstract

PURPOSE:To correct fluctuation in luminance and white balance between unit screens with high accuracy and semi-automatically by holding the cut-off voltage and the drive voltage of an electron gun at each unit screen. CONSTITUTION:To correct the fluctuation in the luminance and the white balance between unit screens, an optical sensor 8 is provided at the front of each unit screen at an adjustment time. A detected voltage is detected at a detection circuit 9, and is supplied to a comparator 11, and at the comparator 11, it is compared with a reference voltage from a reference voltage generating circuit 10. And a pulse width modulation circuit 13 that is an electron gun driving circuit and a cut-off adjusting circuit 14 are controlled with a control circuit 19 so that the output voltage of the comparator 11 becomes zero through a white balance memory 12 and a cut-off balance memory 15 respectively. Thereby, the fluctuation in the luminance and the white balance between unit screens can be corrected.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to an image display device.

[Background of the invention]

Conventionally, cathode ray tubes have been mainly used as image display elements, but with the advancement of higher definition.

Wideband video circuits and high speed horizontal deflection circuits.

Major technical issues have arisen in the development of high-definition technology, and this has become an obstacle to achieving higher definition. On the other hand, as an image display device, an image is used.

The surface is divided into multiple unit screens, and an electron beam is generated for each unit screen.

A system in which the electron beam is deflected horizontally and vertically is known. (Japanese Unexamined Patent Publication No. 57-1j3780) This method is advantageous for achieving high definition because the required performance of the video circuit and horizontal deflection circuit can be reduced in proportion to the number of divisions. However, in the conventional image display device of this type, sufficient consideration has not been given to correcting variations in brightness and white balance between unit screens.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide an image display device that can semi-automatically correct variations in brightness and white balance between unit screens with high accuracy.

[Summary of the invention]

In order to achieve the above object, the present invention provides an art guide.

The display device is each electron gun in charge of each unit screen.

Cutoff voltage and drive voltage of each unit.

from the light sensor installed in front of the cut screen during adjustment.

The output voltage of the electron gun is controlled so as to reduce the error with a separately provided reference voltage, and the latter is further adjusted.

The structure is such that the cutoff voltage and drive voltage can be stored in memory as digital data.

It is.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 1st
In the figure, 1a, 1b, 1c, 1d are electron guns, 2α
, 2b, 2c are vertical deflection voltage application terminals, 3α, y, b
, 5c is a vertical deflection electrode, 4a, 4h.

4C is a horizontal deflection voltage application terminal, 5a, 5h, and 5C are horizontal deflection electrodes, 6 is a fluorescent screen, and 7α.

, 7b, 7c, yd are unit screens, 8 is a light sensor,
A comparator, 12 a white balance memory, 16 a pulse width modulation circuit, 14 a cutoff adjustment circuit, 15 a cutoff balance memory 0.16 a signal frame memory, and 17 a dump.

A ring circuit, 18 a signal generation circuit, and 19 a control.

Circuits 20, 21, and 22 are RGB signal input terminals.

be.

Next, FIG. 1 while referring to FIGS. 2 to 3.

Explain the operation.

Electron guns 1α, 1h, 1cm, and 1d are normal plows.

Heater, power, similar to that used in tubes.

It consists of a sword, a grid electrode, a focus electrode, etc., and the unit screens 7a, 7b, 7c.

7d, and the phosphor screen is caused to emit light by the electron beam generated therefrom.

The vertical deflection electrodes 6a, 5b, and 5c are conductive plates arranged in the horizontal direction, and serve as vertical deflection voltage application terminals 2a.

At 2t and 2c, the vertical deflection voltage V+ with the waveform shown in FIG.
, V2 is applied differently between the opposing electrodes to deflect the electron beam in the vertical direction.

The horizontal deflection electrodes 5α, 5b, and 5C are conductive plates arranged in the vertical direction, and are horizontal deflection voltage application terminals 4α.

・ 6 ・ 4h, 4c Nemo tg 2 nno pressure V+, V
Similar to 2.

Two sets of voltages are applied differently between opposing electrodes.

Well, it deflects the electron beam horizontally.　　.

In FIG. 3, electrodes 3a, 5c, 5a, and 5C are electrically connected.

, electrode 5h, 5h is e1! E-bee in case of rank.

23α, 23h.

23C, 2Fsd is an electron beam when there is no deflection electric field.

The human positions are 23α', 23J', 2roC', 27I
d' is this bias.

It shows the electron beam position in the forward electric field. From FIG. 6, the scanning directions of the electron beams on the unit screens 7α 7h, 7c, and 7d differ by 1°, respectively.

electron at any position within each conit screen.

It can be seen that the beam can be deflected. Fluorescent screen.

6 is composed of vertically striped phosphors as shown in FIG.

In order to perform color display with a single electron beam, the amount of electron beam is divided into R, G, and B in synchronization with the horizontal electrostatic deflection.
The signal is modulated by J:.

Since the electron guns 7α 7J, 7c, and 7d have variations in characteristics due to assembly errors, etc., it is necessary to correct the variations in brightness and white balance between the screens of each unit. The present invention does this semi-automatically.

For easy and accurate correction, each adjustment is made at the time of adjustment.

A light sensor 8 is provided in front of the unit screen.

The voltage is increased to an appropriate voltage level by the detection circuit 9.

The output voltage of this detection circuit 9 and the reference voltage are generated.

and the output voltage from the main circuit 10 by the comparator 11.

The output voltage of this comparator 11 is controlled by the control circuit.

control circuit 19 to the comparator.

Electron gun drive circuit so that the output voltage of 11 becomes 0.

A pulse width modulation circuit 16. Cut-off heat adjustment.

Each circuit 14 is connected to a white balance memory 12.
It is controlled via a cutoff balance memory 15. The video signal is RGB primary color signal 20, 21, 2
2, is sampled as digital data by the sampling circuit 17, and is stored in the frame memory 16.
Frame worth of data is stored in memory, and necessary data is input to the pulse width modulation circuit 13 in synchronization with the deflection circuit.

The Hals width adjustment circuit 16 applies a pulse width modulated voltage as shown in FIG. 5 according to the video signal level to, for example, the grid of the electron gun.

Each unit is connected to memory 12 for white balance.

Drive data specified for each cut screen.

Correct the voltage EG between each unit screen.

Corrects variations in white balance. .

〔Effect of the invention〕

As explained above, according to the present invention, the screen.

Split the unit screen into multiple unit screens.

In a 1° image display device that generates an electron beam and deflects the electron beam horizontally and vertically for each unit screen, an optical sensor is installed in front of each unit screen when adjusting variations. We compare the output voltage from the output voltage with a separately provided reference voltage, and control the power, off voltage, and drive voltage of each electron gun that controls each unit screen to reduce this error. Even after adjusting for variations, the digital data is Since the configuration is such that it can be maintained as follows, it has the effect of being able to semi-automatically and highly accurately correct variations in brightness and white balance between the screens of each unit.

[Brief explanation of drawings]

FIG. 1 shows an image display device according to an embodiment of the present invention. The configuration diagram, Figure 2 is a voltage waveform diagram for electrostatic deflection, Figure 3 is a diagram of the electron beam deflection pattern, and Figure 4 is a firefly diagram. FIG. 5 is a state diagram of the phosphor on the light surface, and is a diagram of the output voltage waveform of the pulse width modulation 4 circuit. 8... Optical sensor, 9... Detection circuit, 10... Reference voltage. Pressure generating circuit, 11... Comparator, 16... Pulse width variation. Adjustment circuit, 14... Cutoff adjustment circuit, 17... Combining circuit, 1B... Signal generation circuit, 19...
18 control circuit. 7)-・-＼ Kasumi 1 Fig. 1 ■ Fig. 2 3 Fig. ■ ○ ■

Claims (1)

[Claims] 1. A screen on a phosphor screen is divided into a plurality of unit screens, a plurality of electron guns that cause each of the unit screens to emit light, a plurality of electron gun drive circuits that drive the plurality of electron guns, and each of the above unit screens. In an image display device provided with a plurality of deflection devices for deflecting electron beams, an optical sensor is provided in front of the unit screen during adjustment, and a comparator is further provided to compare the output voltage of the optical sensor with a reference voltage, An image display device characterized in that variations in brightness and white balance of the unit screen can be corrected by controlling the plurality of electron gun drive circuits using the output voltage of the comparator.