JPH07182992A - Image display device - Google Patents

Abstract

PURPOSE:To adjust by the user or automatically optimize the degradation of image quality due to variation of a peripheral magnetic field by permitting the user to freely shift a horizontal electron beam position in an entire screen according to the state of the screen. CONSTITUTION:Horizontal deflection data read out by a DMA controller 41 from a deflection memory 42 into which deflection data adjusted in their certain status during the operation of an image display device are written is latched by a horizontal deflection data latch 44h. Correction data common to an entire screen is added to this data by means of an adder 46a and an output timing adjusting latch 46b and sent to a horizontal deflection D/A43h. Then the entire electron beam is moved by the correction data in the horizontal direction. Thereby, even if the peripheral magnetic field such as geomagnetic field is varied and the electron beam of the entire screen is shifted, the user himself can recover its original status by performing adjustment by using the correction data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention displays a plurality of dots by horizontally deflecting an electron beam for each division when a screen on a screen is divided into a plurality of horizontal and vertical directions. Deflection in the direction to display multiple lines,
The present invention relates to a device for displaying an image as a whole.

[0002]

2. Description of the Related Art The basic structure of an image display element used in a conventional image display device will be described with reference to FIG.

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

The cathode 2 as an electron beam source is stretched in the horizontal direction so as to generate an electron beam that is linearly distributed in the horizontal direction, and a plurality of cathodes 2 are provided at intervals in the vertical direction ( In this description, only 7 of 2 a to 2 g are shown). In this configuration, the cathodes are spaced apart by 4.4 mm and the number of cathodes is 19, and the number of cathodes is 2 to 2. The space between the cathodes cannot be freely set large, and is regulated by the space between the vertical deflection electrode 7 and the screen 8 which will be described later. As the structure of these 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 cathode is controlled so as to sequentially emit an electron beam from the upper cathode 2a to the lower two cathodes at regular intervals.

The back electrode 1 suppresses the generation of electron beams from cathodes other than the corresponding cathode, and also has the function of pushing out the electron beams only in the anode direction. Although the vacuum container is not shown in FIG. 3, it is possible to use the back electrode 1 to form a structure integrated with the vacuum container. The electron beam extraction electrode 3 is a conductive plate 11 having a plurality of through holes 10 that are arranged in a row in the horizontal direction facing each of the cathodes 2a to 2c at regular intervals.
The electron beam emitted from is taken out through the through hole 10.

Next, the signal modulation electrode 4 is composed of a vertically long conductive plate 15 having a through hole 14 at a position facing each of the cathodes 2A to 2C, and a plurality of horizontally arranged conductive plates 15 are arranged at predetermined intervals. Individually installed. 114 in this configuration
Conductive plates 15a to 15n for signal modulating electrodes are provided (only eight are shown in FIG. 3). The signal modulation electrode 4 synchronizes the passing amount of each electron beam divided in the horizontal direction by the electron beam extraction electrode 3 in correspondence with the picture element of the video signal and in synchronization with the horizontal deflection timing described later. Have control.

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 signal modulation electrode 4, and focuses the electron beam. The horizontal deflection electrodes 6 are electrically conductive plates 18 and 18 'arranged in a plurality in the vertical direction along both sides of the through hole 16 in the horizontal direction.
The horizontal deflection voltage is applied to each conductive plate. The electron beam for each picture element is 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, each electron beam is deflected by 2 trio.

The vertical deflection electrode 7 is composed of a plurality of conductive plates 19 and 19 'arranged in the horizontal direction at intermediate positions in the vertical direction of the through hole 16, and a vertical deflection voltage is applied to the vertical deflection electrode 7. The electron beam is vertically deflected.
In this configuration, the electron beam generated from one cathode is vertically deflected by 12 lines by the pair of electrodes 19 and 19 '. The vertical deflection electrode 7 composed of 20 pieces corresponds to each of the 19 cathodes.
Nine pairs of vertical deflection conductors are constructed, drawing 228 horizontal scan lines vertically on the screen 8. As described above, in this configuration, the horizontal deflection electrodes 6 and the vertical deflection electrodes 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, horizontal and vertical co-deflection distortion can be reduced.

As shown in FIG. 3, the screen 8 is formed by coating the back surface of the glass plate 21 with the phosphor 20 in a stripe shape. Also, although not shown, a metal back, a car
Bon is also applied. The phosphor 20 is provided so that the electron beam passing through one through hole 14 of the signal modulation electrode 4 is horizontally deflected to irradiate the phosphor pairs of three colors of R, G and B for two trio. And is applied in stripes in the vertical direction. In FIG. 3, the broken lines drawn on the screen 8 indicate vertical divisions displayed corresponding to the plurality of cathodes 2, and the two-dot chain line corresponds to each of the plurality of signal modulation electrodes 4. Indicates the horizontal division displayed. FIG. 4 shows an enlarged view of one section divided by a broken line and a two-dot chain line.

As shown in FIG. 4, two trio R, G, and B phosphors in the horizontal direction and a width of 12 lines in the vertical direction are provided. The size of one section is 1 in the horizontal direction in this example.
mm, vertical direction 4.4 mm. In FIG. 4, R, G, B
Each of the three color phosphors is illustrated as a stripe,
They may be arranged in a delta shape. However, when they are arranged in a delta shape, it is necessary to apply horizontal deflection and vertical deflection waveforms suitable for them. Also, in FIG. 4, for the sake of convenience of explanation, the vertical and horizontal dimensional ratios are different from the actual image displayed on the screen. Further, in this configuration, one through hole 1 of the signal modulation electrode 4 is provided.
The phosphors of R, G, and B are provided for 2 trios for 4, but may be constructed for 1 trio or for 3 trios or more. However, R, G, and B video signals of 1 trio or 3 trios or more are sequentially applied to the signal modulation electrode 4, and it is necessary to perform horizontal deflection in synchronization with them.

Next, the operation of the drive circuit for driving this display element will be described with reference to FIG. First, the drive portion for irradiating the screen 8 with the electron beam and displaying the same will be described. The power supply circuit 22 is a circuit for applying a predetermined bias voltage to each electrode of the display element. The back electrode 1 is V1, the electron beam extraction electrode 3 is V3, and the focusing electrode 5 is V3.
5. A DC voltage of V8 is applied to the screen 8.

The pulse generating circuit 39 creates a cathode drive pulse using the vertical synchronizing signal V and the horizontal synchronizing signal H. FIG. 7 shows the timing chart. Each cathode 2a ~
As shown in (Fig. 5 (a) to (c)), the two are heated by the current flowing while the driving pulse is at a high potential, so that the driving pulse (a to t) emits electrons during a low potential period. The heating state is maintained.

As a result, electrons are emitted from the 19 cathodes 2a to 2t only during the 12 horizontal scanning periods in which low-potential drive pulses (a tot) are applied. To compose one screen, the upper cathode 2a to the lower cathode 2
It suffices to sequentially switch the potentials every 12 scanning periods until the end.

Next, the deflecting portion will be described with reference to FIGS. The deflection voltage generating circuit 40 includes a direct memory access controller (hereinafter referred to as a DMA controller) 4
1. Deflection voltage waveform storage memory (hereinafter referred to as deflection memory) 42, horizontal deflection D / A 43h, vertical deflection D / A
43v, a horizontal deflection 8BIT data latch 44h, a vertical deflection 8BIT data latch 44v, a horizontal deflection high voltage amplifier 45h, a vertical deflection high voltage amplifier 45v, and the like. The vertical deflection signals v, v'and the horizontal deflection signal h , H ′ are generated. In this configuration, the vertical deflection signal is displayed in one field for 228 horizontal scanning periods in consideration of overscan. Also, the memory address area storing the vertical deflection position information corresponding to each line is divided into a first field and a second field, and each has a set of memory capacity.

When displaying, the data is read from the corresponding deflection memory 42 and the vertical deflection 8BIT data latch 44 is read.
Vertical deflection data is latched by v and vertical deflection D / A 43v
High-voltage amplifier for vertical deflection 4
After being amplified by 5 V, it is added to the vertical deflection electrode 7. The vertical deflection position information stored in the deflection memory 42 is composed of data having almost regularity every 12 horizontal scanning periods, and the waveform converted into the deflection signal is also a vertical deflection signal of approximately 12 stages. It's becoming 2 but as mentioned above
The memory capacity for the field is provided so that the position can be finely adjusted for each horizontal scanning line.

With respect to the horizontal deflection signal, it is necessary to horizontally deflect the electron beam in six steps in one horizontal scanning period, and a memory is provided so that the deflection position can be finely adjusted for each horizontal scanning. Therefore, in order to display 456 horizontal scanning periods in one frame, a memory of 456 × 6 = 2736 bytes is required, but the data of the first field and the second field is
Since the data is shared, 1368 bytes of memory are actually used. When displaying, the deflection information corresponding to each horizontal scanning line is read from the deflection memory 42,
The horizontal deflection data is latched by the horizontal deflection 8BIT data latch 44v, converted into an analog signal by the horizontal deflection D / A 43v, amplified by the horizontal deflection high voltage amplifier 45v, and then applied to the horizontal deflection electrode 7.

In summary, during the display period excluding the vertical blanking period of the vertical cycle, the electron beam emitted from the cathode to which the low-potential drive pulse of the cathodes 2 to 2 is applied. Are divided into 114 sections in the horizontal direction by the beam extraction electrode 3 to form 114 electron beam trains. As will be described later, the electron beam is controlled by the signal modulating electrode 4 for each passing amount of the beam, and after being focused by the focusing electrode 5, the electron beam changes in almost six stages as shown in FIG. R1, G1, B1 and R of the screen 8 in each horizontal display period by the horizontal deflection electrodes 18 and 18 'to which a pair of horizontal deflection signals h and h'are added.
Phosphors such as 2, G2, and B2 are sequentially irradiated with each horizontal display period / 6.

Thus, the raster of each horizontal line is 11
A color image can be displayed on the screen 8 by modulating the electron beam for each of the four sections with the video signals corresponding to R1, G1, B1 and R2, G2, B2. .

Next, the modulation control portion of the electronic beam will be described. First, in FIG. 5, the signal input terminals 23R, 23
Each R, G, B video signal added to G, 23B is 1
Fourteen sample-hold circuit sets, 31a-31n, are added. The sample-hold circuit groups 31a to 31n are respectively for R1, G1, B1, and R2, G2.
And B2 for six sample-hold circuits.

The sampling pulse generating circuit 34 has a horizontal display period (about 50 μsec) of a horizontal period (63.5 μsec).
The 114 sets of sample-hold circuits 31a to 31
n for each of R1, G1, B1, and R2, G2
6114 (114.times.6) sampling pulses Ra1 to Rn2 corresponding to the B and B2 sample hold circuits are sequentially generated. Each of the 684 sampling pulses has 114 sets of sample-hold circuit sets 31a to 31.
Six pieces are added to n, so that in each sample-hold circuit group, R1, G1, B1, R2, G2, and B of two picture elements when one line is divided into 114 pieces.
Each of the two video signals is individually sampled and held. 114 sets of sampled R1, G1, B
The video signals of 1, R2, G2, and B2 are transferred all at once to the 114 sets of memories 32a to 32n by the transfer pulse t after the end of the sample hold for one line, and are held there for the next one horizontal scanning period.

The held R1, G1, B1, R2,
The signals of G2 and B2 are 114 switching circuits 35a.
~ 35n. Switching circuits 35a-35
n is R1, G1, B1, R2, G2, B2, respectively.
And a common output terminal that sequentially switches and outputs them, and switches simultaneously by switching pulses r1, g1, b1, r2, g2, b2 added from the switching pulse generation circuit 36. Controlled.

The switching pulses r1, g1, b
1, r2, g2b2 divide each horizontal display period into six,
Horizontal display period / 6 switching circuits 35a to 35n
To output the video signals of R1, G1, B1, R2, G2, and B2 in a time-divisional manner and sequentially output the pulse width modulation circuit 37.
a to 37n. Each switching circuit 35a
The output of ~ 35n is 114 sets of pulse width modulation (hereinafter PW
M) circuit 37a-37n, R1, G
The pulse width is modulated according to the magnitude of each of the video signals of 1, B1, R2, G2, and B2 and is output. The outputs of the pulse width modulation circuits 37a to 37n are individually applied to 114 conductive plates 15a to 15n of the signal modulation electrode 4 of the display element as signals for modulating the electron beam.

Next, the timing of horizontal deflection and display will be described. R in the switching circuits 35a to 35n
Switching of the video signals of 1, G1, B1, R2, G2 and B2, and the electronic beam R by the horizontal deflection signal generator 43h
The synchronization control is performed so that the switching timing and the order of horizontal deflection of the phosphors of 1, G1, B1, R2, G2, and B2 to the phosphors completely match. As a result, when the R1 phosphor is irradiated with the electron beam, the irradiation amount of the electron beam is controlled by the R1 modulation signal, and G1, B1, R
2, G2, and B2 are controlled in the same manner, and the emission of each phosphor of R1, G1, B1, R2, G2, and B2 of each picture element is changed to that of R1, G1, B1, R2, G2, and B2 of that picture element. Each picture element is controlled by the video signal, and each picture element is luminescently displayed according to the input video signal.
This control is simultaneously executed for 114 sets (two picture elements each) for one line, an image of 228 picture elements for one line is displayed, and one field 228 lines are sequentially performed from the upper line. Then, the image is displayed on the screen 8. Further, the above-described operations are repeated for each field of the input video signal, and the television signal or the like is displayed on the screen 8.

[0024]

However, in the above-described structure, the electron beam moves due to a change in the peripheral magnetic field due to the earth's magnetism, etc. in a high-definition image display device, and especially in the case of horizontal movement. There is a problem that the color shift appears and the image quality is significantly deteriorated.

In view of the above problems, the present invention provides an image display device capable of user adjustment or automatically optimizing deterioration of image quality caused by movement of an electron beam due to a change in peripheral magnetic field.

[0026]

In order to solve the above problems, the image display apparatus of the present invention is such that the user can freely move the horizontal electron beam position of the entire screen according to the screen. Further, instead of the user adjustment, a change in the peripheral magnetic field due to the earth's magnetism or the like is detected by using a magnetic sensor and automatically adjusted.

[0027]

With the above-described structure, the present invention allows the user to freely adjust the horizontal electron beam position on the entire screen of the image display apparatus in accordance with the screen so that the optimum image quality can be adjusted. Further, instead of the user adjustment, the change in the peripheral magnetic field due to the earth's magnetism or the like is detected by the magnetic sensor, and the optimum electron beam position is automatically adjusted by the correction data based on the output.

[0028]

【Example】

(Embodiment 1) An image display apparatus according to a first embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a deflection voltage waveform generating circuit of an image display device.

In FIG. 1, 39 is a pulse generating circuit for generating various pulses, 41 is a DMA for controlling the deflection memory.
A controller 42 is a deflection memory for storing data of horizontal and vertical deflection voltage waveforms, and 43h is a horizontal deflection D /
A and 43v are D / A for vertical deflection, 44h is a data latch for horizontal deflection, 44v is a data latch for vertical deflection, and 45h.
Is a high voltage amplifier for horizontal deflection, 45v is a high voltage amplifier for vertical deflection, and 46 is an adder for adding horizontal deflection data and correction data from the deflection memory and a data latch for output timing.

The operation of the image display device configured as described above will be described below with reference to FIG.

A deflection memory 42 in which deflection data adjusted in a certain state is written when the image display device operates.
Therefore, the horizontal deflection data read by the DMA controller 41 is latched by the horizontal deflection data latch 44h, and then corrected by the adder and the output timing adjusting latch 46 with the correction data common to the entire screen to obtain the timing. After that, it is sent to the horizontal deflection D / A 43h. At that time, the electron beam on the entire screen moves in the horizontal direction by the correction data based on the original horizontal deflection data.

By the above operation, when the image display device is moved from the adjusted state to the place and the peripheral magnetic field such as the earth's magnetism is changed, the electron beam on the entire screen is made uniform with respect to the uniform magnetic field such as the earth's magnetism. Therefore, the user can adjust the correction data common to the entire screen through the microcomputer or the like to restore the original image quality.

(Embodiment 2) An image display apparatus according to a second embodiment of the present invention will be described below with reference to FIGS.

The operation of FIG. 1 is as described in the first embodiment, and the following description will be centered on FIG. 2 which is different from the first embodiment.

FIG. 2 shows an electron beam position automatic adjustment circuit of the image display device. In FIG. 2, 50 is a magnetic sensor, 51 is a voltage amplifier that amplifies a minute signal from the magnetic sensor, 52 is an A / D converter (analog / digital converter), and 53 is a correction data calculation microcomputer.

The operation of the image display device configured as described above will be described below with reference to FIGS. 1 and 2.

Since the horizontal electron beam movement amount due to the change of the peripheral magnetic field of the image display device is proportional to the vertical component of the peripheral magnetic field, the vertical component of the peripheral magnetic field is detected by the magnetic sensor 5.
Detect by 0. A microcomputer 5 for calculation that amplifies a minute signal from the magnetic sensor 50 by a voltage amplifier 51, converts it into a digital signal by an A / D 52, and then calculates correction data.
3 to the correction data input of the deflection voltage waveform generation circuit (FIG. 1). Therefore, the measurement of the magnetic field, the calculation of the correction data, and the movement of the electron beam in the horizontal direction are automatically performed.

The method of detecting and processing the magnetic field may be a method other than the above.

[0039]

As described above, according to the image display apparatus of the present invention, it is possible to freely adjust the movement of the electron beam of the entire screen generated in response to the change of the peripheral magnetic field such as the earth magnetism to the optimum electron beam position. You can Also, automatic adjustment can be performed by detecting the peripheral magnetic field.

[Brief description of drawings]

FIG. 1 is a block diagram showing a deflection voltage waveform generation circuit of an image display device which is an embodiment of the first invention of the present invention.

FIG. 2 is a block diagram of an electron beam position automatic adjustment circuit of an image display apparatus which is an embodiment of the second invention of the present invention.

FIG. 3 is an exploded perspective view of an image display device as a conventional example.

[Figure 4] Enlarged view of the screen

[Figure 5] Basic drive circuit diagram

FIG. 6 is a detailed block diagram of the deflection voltage waveform generation circuit.

FIG. 7 is a diagram showing various waveform timings of the same.

[Explanation of symbols]

 39 Pulse generation circuit 41 DMA controller 42 Deflection memory 43h, 43v D / A converter 44h, 44v 8BIT data latch 45h, 45v High voltage amplifier 46 Horizontal deflection data addition circuit 46a Adder 46b Output timing adjustment latch 47h, 47v AND circuit 48 Pull-up resistor 18, 18 'Horizontal deflection voltage waveform output 19, 19' Vertical deflection voltage waveform output 50 Magnetic sensor 51 Voltage amplifier 52 A / D converter 53 Computing microcomputer

Claims (2)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam, a plurality of cathodes that generate an electron beam for each vertical section that divides the screen on the screen in the vertical direction, and A back electrode for controlling the amount of the electron beam emitted from the cathode, and a separating means for separating the electron beam for each horizontal section obtained by horizontally dividing the electron beam generated at the cathode and irradiating the screen with the electron beam. A horizontal deflection electrode for deflecting the electron beam in a plurality of steps in the horizontal direction until reaching the screen, a vertical deflection electrode for deflecting the electron beam in a plurality of steps in the vertical direction reaching the screen, and for each horizontal section A signal modulation electrode for controlling the amount of electron beams separated into two parts to irradiate the screen to control the light emission amount of each picture element on the screen of the screen. And an image display device characterized in that the user can freely move the horizontal electron beam position of the entire screen. 2. The image display device according to claim 1, wherein a change in the peripheral magnetic field due to geomagnetism or the like is detected by using a magnetic sensor, and the electron beam position is automatically adjusted to the optimum position.