JPH077709A - Automatic adjustment device for picture display device - Google Patents

Abstract

PURPOSE:To automatically and accurately adjust a correction signal by providing the adjustment device changing a vertical deflection voltage waveform and the correction signal of the picture display device in response to an output of a signal processing unit. CONSTITUTION:A television camera 51 measures a luminance distribution function in the vertical direction of the picture display device 50 and inputs the measured function to a computer 54 via a camera controller 53. The computer 54 approximates the luminance distribution function for each vertical period with an n-order function based on the position of a scanning line and applies a predetermined arithmetic operation to the function and the correction signal data for each scanning line are transferred to the adjustment device 55. The device 55 adjusts the vertical deflection voltage waveform of the device 50 and the correction signal for each scanning line. Thus, the correction signal is automatically adjusted to obtain a raster with excellent luminance uniformity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generates an electron beam for each section when a screen on a screen is divided into a plurality of sections in the vertical direction, and emits each electron beam in the vertical direction for each section. The present invention relates to an image display device that deflects and displays a plurality of lines to display an image as a whole.

[0002]

2. Description of the Related Art In recent years, various flattening devices for displaying television images have been proposed.

An image display device as a flat-type color picture tube of this type has hitherto been disclosed in, for example, Japanese Patent Application Laid-Open No. 57-135590.
It has a structure as shown in the publication. The configuration will be described below with reference to the drawings.

As shown in FIG. 3, this image display device has a back electrode 1, a line cathode 2 as an electron beam emission source, an electron beam extraction electrode 3, and an electron beam emission electrode 3 in this order from the rear to the anode side.
A beam flow control electrode 4, a focusing electrode 5, a horizontal deflection electrode 6, a vertical deflection electrode 7, a screen 8 and the like are arranged and configured, and these are housed inside a vacuum container.

The operation of the flat type image display device constructed as described above will be described below. As shown in FIG. 3, the line cathode 2 as an electron beam emission source is stretched horizontally so as to generate electron beams that are linearly distributed horizontally, and the line cathode 2 is further vertical. A plurality of lines (only 7 lines 2a to 2g are shown in FIG. 3) are provided at regular intervals in the direction. In this configuration, the line cathodes are spaced at 4.4 mm and the number of line cathodes is 19, and the line cathodes are 2 to 2 in number. The distance between the line cathodes cannot be set freely, and is regulated by the distance between the vertical deflection electrode 7 and the screen 8 which will be described later. As the 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 line cathode is controlled so as to sequentially emit an electron beam from the upper line cathode 2a to the lower two line cathodes at regular intervals.

The back electrode 1 suppresses the generation of electron beams from the line cathodes other than the corresponding line cathode, and at the same time, the electron beam is emitted.
It also has the function of pushing the mud only in the anodic direction. Figure 3
Although a vacuum container is not shown, it is possible to use the back electrode 1 to form a structure integrated with the vacuum container. The electron beam lead-out 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 the respective line cathodes 2 a to 2 at regular intervals and are emitted from the line cathode 2. The electron beam is taken out through the through hole 10.

Next, the beam flow control electrode 4 is connected to the line cathodes 2a to 2b.
A plurality of vertically long conductive plates 15 each having a through hole 14 at a position facing each other are arranged side by side in a horizontal direction at a predetermined interval. 11 in this configuration
Four beam flow control electrode conductive plates 15a to 15n are provided (only eight are shown in FIG. 3). The beam flow control electrode 4 synchronizes the passing amount of each electron beam divided in the horizontal direction by the electron beam extraction electrode 3 with the pixel of the video signal and in synchronization with the horizontal deflection timing described later. Let me 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 beam flow control electrode 4, and focuses the electron beam.

The horizontal deflection electrode 6 is composed of a plurality of conductive plates 18 and 18 'vertically arranged along both sides of the through hole 16 in the horizontal direction. Voltage is applied. The electron beam for each pixel 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 the respective intermediate positions in the vertical direction of the through hole 16, and a voltage for vertical deflection is applied to the vertical deflection electrode 7 to generate an electronic beam. -The beam is deflected vertically. In this structure, the electron beam generated from one line cathode is vertically deflected by 12 lines by the pair of electrodes 19 and 19 '. The 20 vertical deflection electrodes 7 constitute 19 pairs of vertical deflection conductors corresponding to the 19 line cathodes, respectively, and 228 horizontal scanning lines are provided on the screen 8 in the vertical direction. Is drawn.

As described above, in this structure, a plurality of horizontal deflection electrodes 6 and 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 surface of the screen 8 with the electron beam with a small deflection amount. This makes it possible to reduce deflection distortion both horizontally and vertically.

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 deflects the electron beam passing through one through hole 14 of the beam flow control electrode 4 in the horizontal direction to form two phosphor pairs of three colors of R, G and B.
It is provided to irradiate the amount of trio, and is applied in stripes in the vertical direction. In FIG. 3, the broken lines on the screen 8 indicate vertical sections displayed corresponding to the plurality of line cathodes 2, and the two-dot chain line corresponds to each of the plurality of beam flow control electrodes 4. Indicates the horizontal division displayed. As shown in the enlarged view of FIG. 4, one section divided by a broken line and a two-dot chain line has two trio R, G, and B phosphors in the horizontal direction and a width of 12 lines in the vertical direction. ing. In this example, the size of one section is 1 mm in the horizontal direction and 4.4 mm in the vertical direction.

Next, the operation of the drive circuit for driving this image display element will be described with reference to FIG.

First, the drive portion for irradiating the electronic beam on the screen 8 for display will be described. The power supply circuit 22 is a circuit for applying a predetermined bias voltage to each electrode of the image display element. The back electrode 1 has V1 and the electron beam extraction electrode 3
Is V3, the focusing electrode 5 is V5, and the screen 8 is V8.
Apply the DC voltage of.

The pulse generating circuit 39 uses the vertical synchronizing signal V and the horizontal synchronizing signal H to create a line cathode drive pulse.
FIG. 6 shows an example of the timing.

The line cathode drive circuit 26 receives the line cathode drive pulse and heats the line cathode 2 while the drive pulse is at a high potential. At this time, the heated line cathode is applied to the line cathode 2 more than the potential around the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the electron beam extraction electrode 3. Electrons are not emitted from the line cathode because the potential that is present is higher.

On the other hand, the line cathode 2 emits electrons while the drive pulse is at a low potential. At this time, the line cathode 2 has a potential applied to the line cathode 2 more than a potential around the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the electron beam extraction electrode 3. Since it becomes lower, electrons are emitted from the line cathode 2.

As is apparent from the above description, electrons are emitted from the 19 line cathodes 2a to 2t only during the 12 horizontal scanning periods in which low potential driving pulses (a tot) are applied. In order to form one screen, it is sufficient to sequentially switch the potentials from the upper line cathode 2a to the lower line cathode 2 by 12 scanning periods.

Next, the deflection portion will be described. As shown in FIG. 5, the deflection voltage generation circuit 40 includes a direct memory access controller 41, a deflection voltage waveform storage memory (hereinafter referred to as deflection memory) 42, and a horizontal deflection signal generator 43.
h, a vertical deflection signal generator 43v, etc.,
It produces vertical deflection signals v, v'and horizontal deflection signals h, h '. In this configuration, the vertical deflection signal is turned off.
In consideration of the bar scan, 228 horizontal scanning periods are displayed in one field. Further, 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 set has a memory capacity. When displaying, data is read from the corresponding deflection memory 42, converted into an analog signal by the vertical deflection signal generator 43v, and added to the vertical deflection electrode 7.

The vertical deflection position information stored in the deflection memory 42 is composed of substantially regular data every 12 horizontal scanning periods, and the waveform converted into the deflection signal is also approximately 1.
Although it is a two-stage vertical deflection signal, it has a memory capacity of two fields as described above so that the position can be finely adjusted for each horizontal scanning line.

Further, for 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, to display 456 horizontal scanning periods in one frame, a memory of 456 × 6 = 2736 bytes is required, but since the data of the first field and the second field are shared. In fact, it uses 1368 bytes of memory. At the time of display, the deflection information corresponding to each horizontal scanning line is read from the deflection memory 42, converted into an analog signal by the horizontal deflection signal generator 43h, and added to the horizontal deflection electrode 6.

To summarize the above, during the display period excluding the vertical blanking period of the vertical cycle, the low-potential drive pulse of the linear cathodes 2a to 2 is emitted from the linear cathode. The electron beam is divided into 114 sections in the horizontal direction by the electron beam extraction electrode 3 to form 114 electron beam rows. As will be described later, this electron beam is controlled by the beam flow control electrode 4 for each section so as to pass the beam, and after being focused by the focusing electrode 5, it has approximately 6 stages as shown in FIG. Horizontal deflection electrodes 18 and 1 to which a pair of changing horizontal deflection signals h and h'are added.
By 8 ', etc., the R of the screen 8 is
Phosphors such as 1, G1, B1 and R2, G2, 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 surface of 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 part of the electronic beam will be described. First, in FIG. 5, signal input terminals 23R, 2
The R, G, and B video signals added to 3G and 23B are
It is added to 114 sets of sample-hold circuit sets 31a to 31n. Each of the sample-hold groups 31a to 31n is for R1, G1, B1, and R2, G2,
It is composed of six sample-hold circuits for B2.

The sampling pulse generating circuit 34 has a horizontal display period (about 50 μm) of a horizontal period (63.5 μS).
S), the 114 sets of sample-hold circuits 31a ...
31n each for R1, G1, B1, and R2,
68 corresponding to the sample-hold circuit for G2 and B2
Four (114 × 6) sampling pulses Ra1 to Rn
2 is sequentially generated. Each of the 684 sampling pulses has 114 sets of sample-hold circuit sets 31a ...
6 pieces are added to 31n, so that in each sample-hold circuit set, R1, G1, B1, R2, and G for two pixels when one line is divided into 114 pieces.
The video signals of 2 and B2 are 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 signal is applied to 114 switching circuits 35a to 35n.

Each of the switching circuits 35a to 35n is composed of a circuit having individual input terminals of R1, G1, B1, R2, G2 and B2 and a common output terminal for sequentially switching and outputting them, and a switching pulse Switching pulse r applied from the generation circuit 36
Switching control is performed simultaneously by 1, g1, b1, r2, g2, and b2. The switching pulses r1, g1,
b1, r2, g2, and b2 divide each horizontal display period into six, and each horizontal display period / 6 switching circuit 35a-3.
5n are switched and the respective video signals of R1, G1, B1, R2, G2, and B2 are time-divided and sequentially output, and supplied to the pulse width modulation circuits 37a to 37n. Each switching circuit 3
The outputs of 5a to 35n are added to 114 sets of pulse width modulation (hereinafter referred to as PWM) circuits 37a to 37n, and R1 and
PWM is output according to the magnitude of each of the G1, B1, R2, G2, and B2 video signals. This PWM circuit 37a-
The output of 37n is individually applied as a control signal for modulating the electron beam to the 114 conductive plates 15a to 15n of the beam flow control electrode 4 of the display element.

Next, the timing of horizontal deflection and display will be described. Switching of video signals of R1, G1, B1, R2, G2 and B2 in the switching circuits 35a to 35n, and 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 control signal, and G1, B1, R
2, G2, B2 are controlled in the same manner, and the emission of each phosphor of R1, G1, B1, R2, G2, B2 of each pixel is the video signal of R1, G1, B1, R2, G2, B2 of that pixel. That is, each pixel is controlled to emit light according to an input video signal. This control is simultaneously executed for 114 sets (two pixels each) for one line, an image of 228 pixels for one line is displayed, and one field 228 lines are sequentially performed from the upper line, An image is displayed on the surface of the screen 8. In addition, the above-mentioned operations are 1 of the input video signal.
Repeated for each field, a television signal or the like is displayed on the screen 8.

Next, the correction circuit of the video signal will be described. FIG. 7 is a block diagram of a video signal correction circuit.
Reference numeral 80 is an A / D converter for converting an analog video signal into a digital signal, 81 is a multiplier as a correction circuit for correcting the video signal, and 82 is a frame in which information on the luminance distribution of the image display element is recorded. A memory, 83 is an address generation circuit for controlling the frame memory 82.

The brightness distribution information recorded in the frame memory 82 is obtained as follows. First, a video signal having a certain size is input to the image display element. At this time, if each of the image display units constituting the image display element has completely the same characteristics, there is no distortion of the beam, and if each image display unit is arranged at exactly equal intervals, the entire screen is displayed. Although a uniform brightness distribution can be obtained, if there is a deflection distortion or aberration of a beam that is dispersed among image display units, or an image display unit array is disturbed, an uneven brightness portion is generated. The luminance distribution at this time is measured, and the correction signal data corresponding to the so-called negative of the luminance distribution (the bright portion is small,
The dark area is large) is recorded in the frame memory.
At this time, if the video signal having a certain magnitude is corrected by the data recorded in the frame memory 82 and input to the image display element, the uneven brightness of the image display element itself is canceled and the entire screen is canceled. Therefore, a uniform brightness distribution can be obtained.

[0030]

In order to obtain a raster with good uniformity (the connection between the image display units is not visible as a unique pattern) in the image display device as described above, the image display device is used. Must accurately adjust the vertical deflection voltage waveform of each electron beam and the correction signal for each scanning line. However, in the past, the work efficiency was very poor because it was visually adjusted.

The present invention solves the above problems, and provides an automatic adjustment device capable of automatically and accurately adjusting a vertical deflection voltage waveform and a correction signal for each scanning line in such an image display device. Is the purpose.

[0032]

In order to solve the above-mentioned problems, an automatic adjusting apparatus of the present invention comprises a television camera which captures the entire raster of an image display device, a signal processing device which processes a video signal of the television camera, An adjusting device for changing the vertical deflection voltage waveform and the correction signal of the image display device according to the output of the signal processing device.

Further, the signal processing device includes means for converting the luminance distribution function of the raster of the image display device captured by the television camera into a vertical average luminance distribution function by summing in the horizontal direction, and the above image display. A means for measuring the position of the scanning line of the device and a brightness distribution function for each vertical section of the image display device are approximated by an nth-order function with the position of the scanning line as a reference so that the coefficient of the function approaches 0. And a means for changing the vertical deflection voltage waveform, and an average value of the luminance distribution function for each vertical section of the image display device is determined with reference to the position of the scanning line so that there is no difference in luminance between adjacent vertical sections. A means for changing the vertical deflection voltage waveform, and a level of the horizontal line generated at the boundary between the vertical sections of the image display device is detected based on the position of the scanning line, and the vertical deflection voltage waveform is changed so that the horizontal line disappears. Means for obtaining a moving average value based on the luminance distribution function of the image display device, and means for changing the correction signal for each scanning line based on the scanning line position so that the luminance distribution function approaches the moving average value. Have.

As a means for measuring the position of the scanning line, the difference between the luminance distribution function of the image display device and the luminance distribution function when the luminance of the scanning line to be measured is set to 0 is detected and the luminance center of gravity is calculated. It has means for obtaining the position and means for expressing the vertical deflection voltage waveform for each vertical section by the function of the coefficient, amplitude, and offset of the n-th order approximate expression.

[0035]

With the above structure, the television camera measures the vertical luminance distribution function of the image display device, and approximates the luminance distribution function for each vertical section by an nth-order function based on the position of the scanning line,
The vertical deflection voltage waveform is changed so that the coefficient of the function approaches 0, and then the average value of the luminance distribution function for each vertical section is obtained based on the position of the scanning line, and the luminance difference between adjacent vertical sections is eliminated. Change the vertical deflection voltage waveform as shown below, then detect the level of the horizontal line that occurs at the boundary between the vertical sections based on the scanning line position, change the vertical deflection voltage waveform so that the horizontal line disappears, and then change the brightness. The moving average value is obtained based on the distribution function, and the vertical voltage waveform and the scanning line are automatically changed by changing the correction signal for each scanning line based on the scanning line position so that the luminance distribution function approaches the moving average value. The correction signal can be adjusted for each time, and a raster with good brightness uniformity can be obtained.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of an automatic adjustment device for an image display device showing an embodiment of the present invention. In FIG. 1, 50 is an image display device to be adjusted, 51 is a CCD camera, 52 is a robot for moving the CCD camera to a predetermined position, 53 is a camera controller for controlling the CCD camera 51, and 54 is a camera controller 53. A computer 55 to which the data of FIG. 2 is input changes a vertical deflection voltage waveform of the image display device 50 and a correction signal of each scanning line according to the vertical deflection data and the correction signal data of each scanning line which are processed and output by the computer 54. The adjusting device 56 for adjusting by, is controlled by the camera controller 53,
This is a video signal generator for an image display device for displaying an appropriate raster on the image display device 50.

The image display device 50 receives an appropriate video signal (for example, a white raster signal) from the video signal generator 56 synchronized with the CCD camera 51 and performs raster display. CCD
The camera 51 is set by the robot 52 at a position where the entire raster of the image display device 50 is captured. The camera controller 53 controls the CCD camera 51 and
Video output from CCD camera is A / D converted,
Transfer to computer 54. The transferred data is processed by the computer 54 to become vertical deflection data and correction signal data for each scanning line, and transferred to the adjustment device 55.
The vertical deflection voltage waveform of the image display device 50 and the correction signal for each scanning line are adjusted by the adjusting device 55 according to the data transferred to the adjusting device 55.

FIG. 2 is a flow chart for explaining a concrete data processing method. First, the method of measuring the brightness distribution function of the image display device will be described. The brightness distribution function of the raster of the image display device captured by the TV camera is converted into a vertical average brightness distribution function by summing in the horizontal direction. To do.

In FIG. 2, the position of each scanning line of the image display device is measured (step 60). The method of measuring the position of the scanning line will be described. First, the luminance distribution function of the image display device is measured, and then the luminance distribution function when the luminance of the measured scanning line is set to 0 is measured. The position can be obtained by detecting the luminance distribution function of only the scan line to be measured from the obtained difference between the two luminance distribution functions and performing the luminance centroid calculation thereof. Next, the brightness distribution function for each vertical section of the image display device is set to n based on the position of the scanning line obtained in (step 60).
It is approximated by the following function (step 61). Next (Step 6
The vertical deflection voltage waveform is changed so that the coefficient of the function approximated in 1) approaches 0 (step 62). Here, the method of changing the vertical deflection voltage waveform will be described. The vertical deflection voltage waveform for each vertical segment is expressed by a function of several parameters of the nth-order approximation formula, amplitude, and offset. This can be achieved by calculating the vertical deflection voltage of each scan line in the.

Further, since the vertical deflection voltage waveform is changed in (step 62), the position of each scanning line of the image display device is measured again (step 63). Next, the average value of the brightness distribution function for each vertical section of the image display device is calculated (step 63).
The position of the scanning line obtained in step 2 is used as a reference (step 6).
4). Next, the vertical deflection voltage waveform is changed so that there is no difference in brightness between adjacent vertical sections (step 65).

Further, since the vertical deflection voltage waveform is changed in (step 65), the position of each scanning line of the image display device is measured again (step 66). Next, the level of the horizontal line generated at the boundary between the vertical sections of the image display device is obtained with reference to the position of the scanning line obtained in step 66 (step 67). Next, the vertical deflection voltage waveform is changed so that the horizontal line is eliminated (step 68).

Further, since the vertical deflection voltage waveform is changed in (step 68), the position of each scanning line of the image display device is measured again (step 69). Next, a moving average value is obtained based on the brightness distribution function of the image display device (step 7).
0). Next, so that the luminance distribution function approaches the moving average value,
The correction signal for each scanning line is determined and changed based on the position of the scanning line obtained in (step 69) (step 71).

By performing the above operation, a raster with good brightness uniformity can be obtained.

[0045]

As described above, according to the automatic adjusting device of the image display device of the present invention, the distortion of the beam in the image display unit, the characteristic variation among the image display units, the disorder of the arrangement of the image display units, etc. occur. However, it is possible to obtain an image display device in which the change in brightness on the screen is corrected and uniformized, and the image quality uniformity is not impaired.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic adjustment device for an image display device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the automatic adjustment device.

FIG. 3 is an exploded perspective view of an image display element in a conventional example.

FIG. 4 is an enlarged view of a phosphor screen of the image display device.

FIG. 5 is a block diagram of a drive circuit of the image display device.

FIG. 6 is a waveform diagram of each part of the drive circuit of the image display device.

FIG. 7 is a block diagram of a correction circuit of the image display device.

[Explanation of symbols]

 50 image display device 51 CCD camera 52 robot 53 camera controller 54 computer 55 adjusting device 56 video signal generator

Claims (4)

[Claims] 1. A screen coated with a phosphor, a line cathode for generating an electron beam for each vertical section obtained by vertically dividing the screen on the screen into a plurality of sections, and a line cathode for generating an electron beam. Correction signal generating means for correcting a video signal for an image display element that obtains an image by irradiating the phosphor on the screen after the electron beam is deflected in the vertical and horizontal directions. An automatic adjustment device for an image display device, which has a correction means for correcting a video signal in accordance with a correction signal outputted by the correction signal generation means, and drives the image display element by using the video signal corrected by the correction means. In the above, a television camera that captures the entire raster of the image display device, a signal processing device that processes a video signal of the television camera, and An automatic adjusting device for an image display device, comprising: an adjusting device for changing a vertical deflection voltage waveform of the image display device and a correction signal of a video signal. 2. A means for converting a luminance distribution function of a raster of an image display device captured by a television camera into a vertical average luminance distribution function by summing in a horizontal direction,
A means for measuring the position of the scanning line of the image display device and a brightness distribution function for each vertical section of the image display device are approximated by an n-order function with the position of the scanning line as a reference, and the coefficient of the function is 0. And a means for changing the vertical deflection voltage waveform to obtain an average value of the luminance distribution function for each vertical section of the image display device based on the position of the scanning line, and the luminance difference between adjacent vertical sections is Means for changing the vertical deflection voltage waveform so that it disappears, and the level of the horizontal line generated at the boundary between the vertical sections of the image display device is detected based on the position of the scanning line and the vertical deflection voltage waveform is eliminated so that the horizontal line disappears. And a means for changing the brightness distribution function of the image display device to obtain a moving average value based on the brightness distribution function so that the brightness distribution function approaches the moving average value,
2. A means for changing a correction signal of a video signal for each scanning line based on the scanning line position.
An automatic adjustment device for an image display device of the image display device described. 3. As a means for measuring the position of the scanning line, the difference between the brightness distribution function of the image display device and the brightness distribution function when the brightness of the scan line to be measured is set to 0 is detected and the brightness center of gravity is calculated. 3. The automatic adjustment device for an image display device according to claim 2, wherein the position is obtained. 4. The image display device according to claim 2, wherein the vertical deflection voltage waveform for each vertical section of the image display device is expressed by a coefficient, an amplitude, and an offset function of an n-th order approximate expression. Automatic adjustment device.