JPS61101190A - Detecting method of center position of electron beam raster on color cathode ray tube display screen - Google Patents

Abstract

PURPOSE:To obtain excellent detection accuracy by obtaining a pattern position from an irradiated region of an electron beam for pattern display so as to minimize a detection error due to arrangement of fluorescent bodies. CONSTITUTION:A lattice pattern on a cathode-ray tube 31 is picked up by an ITV camera 38 while using the range shown in figure (a) as an image pickup range 39. A picture of extension view shown in the figure (b) is obtained at an output of the camera 38. The output of the camera 38 is stored in a picture memory 42. Then an operation circuit 44 adds outputs of the camera 38 corresponding to the luminescence of the fluorescent body array in the vertical direction of the fluorescent bodies furring luminescence at each fluorescent array in vertical direction. The both extreme ends Pe, Pr in the figure (c) are detected. The luminance distribution in the figure (c) is read from the said memory as the means and the operation circuit 44 obtains again the Pe, Pr by using Xe, He, Xr, Hr as parameters. The true center position of the display pattern is obtained as the center position of the said two points.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for detecting the center position of an electron beam scanning raster on a color cathode ray tube display surface.

[Technical background of the invention and its problems] - Automation of the color cathode ray tube manufacturing process is being promoted from the viewpoint of performance and cost reduction. With this Color Pullarity Magneto, highly skilled technicians adjust the optimal position for each color cathode ray tube by outputting the reproduced image one by one. This means that the deflection coil, convergence magnet, and utility magnet have a strong positional relationship, and if you adjust or move the position of any one part, you will also need to adjust the other two parts, so they will mutually match each other to the best position. The buttons are adjusted according to the feel of the button engineer. It is desired to automate the positioning of these three parts.

Such automatic adjustment is performed by reproducing a desired pattern on a color cathode ray tube, capturing an image of this pattern with a two-dimensional photoelectric conversion element, such as an ITV camera, and processing the image signal using the image signal to control the adjustment of each magnetic field device.

Therefore, high accuracy is required to detect the display position while the image is being displayed on the cathode ray tube.

As a means for this purpose, the position has conventionally been detected as shown in FIG.

For example, when detecting the display position of a green vertical line pattern (1) on a color cathode ray tube, the position of the pattern is imaged by an imaging device as shown in FIGS. It was detected using the following method. Predetermined area (2) including the pattern
is extracted by an imaging device and stored in a memory circuit. In particular, the image data of this memory circuit is separated into a minimum area in order to detect the pattern. FIG. 1(C) K shows an example of image data from which the pattern is extracted. This image data is luminance data of a luminance distribution obtained by A/D converting the video signal obtained from the imaging device and taking the luminance sum value of the light emission output in the vertical direction with respect to the horizontal scanning direction. . That is, the separated area is, for example, 150 x 100 (
mxn), a pixel where X is l and Y is 1 (hereinafter,
The luminance data from (1, 1) to (m, 1), with luminance on the vertical axis and pixel row on the horizontal axis, is shown in Figure 1 (
The brightness distribution is as shown in C). Therefore, the distance Pc from the left edge (XI) of the light emitting display in FIG. 1(C) to the center of gravity of the luminance distribution is determined by the following method.

Let the pixel number in the X direction be m (·m=l~150), and the luminance data of each pixel Dm (m=1~150).

becomes. Find this Pc for Y from 1 to n.

Calculate the average value. In this way, the position of the pattern was determined.

However, a color cathode ray tube is a well-known conventional technology in which red, green, and blue phosphors are arranged over the entire display surface, and an electron beam is incident on these phosphors through a shadow mask, thereby producing a color image. Display.

For this reason, for example, when focusing on a phosphor G of an arbitrary color, depending on the display position of the measurement pattern (for example, a dot pattern), the measurement electron beam can be irradiated as shown in FIGS. 5(a) to 5(d). The positional relationship between the range of the dot pattern P and the phosphor G changes. When the position C between the measurement dot pattern P and the phosphor G changes in this way, the center of gravity of the phosphor in the middle of the measurement pattern changes to 1° even though measurement patterns with the same area are displayed. ! The center of gravity in the irradiation area of the child beam, tb, is shifted from the true center of gravity position 0. The positional deviation between the center of gravity of the light-emitting phosphor and the true center of gravity also applies to the vertical line pattern. Although it depends on the width of the display pattern, the positional deviation can be as much as 1/2 of the distance between the phosphors of the same color, for example, 350μ, which is 7 of the phosphor spacing of 700μ.

Therefore, in the conventional detection method described above, the position of the center of gravity of one light emitting body is determined and the position of the display pattern is detected.

Unable to obtain accurate display position.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for detecting the center position of an electron beam scanning raster on the display surface of a color cathode ray tube, which can accurately detect the true center position in the electron beam irradiation range.

[Summary of the invention]

That is, the present invention displays a desired beam pattern on a color cathode ray tube, transfers this pattern to an imaging camera, and in order to display the pattern on the imaging screen, the center of the scanning range of the electron beam of the color cathode ray tube is displayed. When automatically detecting the position, means for obtaining first and second summed values by adding the imaging output values for each scan in the vertical direction for the light emitting phosphor rows at least at both end positions in the horizontal scanning direction of the pattern; Above 1'J? means for determining the first and second ends of the irradiation range from the horizontal distance within the imaging screen of each phosphor array from which the addition value is obtained, and the first and second ends of the irradiation range; A method for detecting the center position of an electron beam scanning raster on a color cathode ray tube display surface is provided, comprising means for determining an intermediate position between the ends of the display surface of a color cathode ray tube.

The outline of this embodiment is as follows.

A desired pattern, such as a grid pattern, is displayed on a color cathode ray tube in a desired single color, and this pattern is imaged by an imaging camera, and the electron beam scanning range of the color cathode ray tube is used to display the pattern on the imaging screen. When automatically detecting the center position, the image pickup output values are added for each vertical scan in the vertical direction of each light-emitting phosphor in the pattern to obtain a horizontal brightness distribution. Next, the minimum added luminance value on both sides of this luminance distribution is detected. After that, these minimum brightness addition values Xe. Xr
From P4=Xe-H4-K4. Pr=X,+
Calculate Hr llKr. Then Pc = (Pe
This is an example in which the center position is detected by calculating +Pr)/2.

P4...First end Pr...I second in the imaging screen, Kr...Constant Pc...Intermediate position in the electron beam irradiation range Fig. 3 shows the method of the present invention FIG. 2 is a circuit configuration diagram for detecting the center position of an electron beam scanning raster on a color cathode ray tube display surface for explaining an embodiment of the present invention. Namely.

The color cathode ray tube 0 is driven by a well-known television circuit G. This circuit 0 is synchronized with the horizontal synchronization signal, vertical synchronization signal, etc. from the synchronization signal generation circuit Q, and displays a pattern on the display surface (31a) of the cathode ray tube Ov for adjustment of the flame retility magnet (to), etc. In this case, the pattern signal from the pattern signal generation circuit (sub) is displayed in synchronization with the synchronization signal from the synchronization signal generation circuit (sub).

For example, a grid butter 7 made of green phosphor is displayed as a pattern. In this state, move the two-dimensional imaging means, such as an ITV camera, mounted on the XYZ table color η to a desired position, and set the imaging range (field of view) marked G as shown in FIG. 2(a), for example. image as An enlarged image shown in FIG. 2(b) is obtained from the output of the ITV camera. This figure (b) is an explanatory diagram showing an enlarged view of the imaging range 09 in figure (a), and the imaging range C31 is illustrated at the corner of the first display surface (31a), and the thick dotted line indicates the signal pattern described above. A vertical green emitting band (40 is shown), each minus line representing a green emitting fluorescent dot.

The green light emitting band (41) within the imaging range C9 indicates the output signal of the ITV camera.The output of the ITV camera is binarized (A/
After D conversion), the signal is stored in one image memory (4a). The signal stored in this image memory (4a) undergoes the following signal processing. A flowchart is shown in FIG.

In other words, the control circuit G! has a microprocessor as its main controller. 9, the image signal shown in FIG. For each scan by the electron beam of the camera (c), the ITV camera outputs a luminance signal corresponding to the amount of light emitted by each light emitting phosphor in the direction (1, 1) perpendicular to the horizontal scanning direction, ( 1,2)...(1,n), (2,
1), (2,2)...(2,0)... are added for each phosphor row. This added value is stored column by column in the memory of the IIJ control circuit. The memory contents are, for example, the second
The result will be as shown in Figure CC) (Step A). In this diagram (C), the horizontal axis represents the distance (position) in the m direction in the imaging range G9, and the vertical axis represents the luminance signal section or the ITV camera (the sum of the force outputs. Therefore, the fourth The position of the light-emitting phosphor array shown by the dotted line in the figure (+)) is on the left, so the second (ζ(
C) is elm and Xe.・・・・・・・・・・・・・Xr
Show it here.

The position of the origin in FIG. 2(C) corresponds to the position (1, n) in FIG. 2(b). If we look at such Figure 2 (C1).

-47 - The brightness at the first rainbow in the light array K4
It can be seen that the value is negative (step B). However, in order to emit light in this four-color luminescence band (4G), the electron beam must actually be irradiated over a wider range, and the actual ``single beam irradiation range '5L'' needs to be detected. In other words, nine cars 4 P4 in the electron beam irradiation area
, detect the Pr value. As a means of this, the 21st U.
The luminance distribution of I(c) is read from the memory and the next calculation is performed by the calculation circuit (4 gradients).

P, = X, -H4・Ktlo, (1) P-=X
r + Hr llKr - (2) In the above formula, X... left side minimum green fluorescent main row position (left end) Xr
・Minimum green phosphor row position (right end) on the right side...Additional brightness value on the left side...〃〃 on the right side
〃 4. Kr...Constant P4 position in Figure 4(c) is determined by calculation of equations (1) and (2).

The Pr position value, that is, the left and right end positions in the electron beam irradiation area can be determined (step C).

p4. The true center of gravity position (Pc) of the υ display pattern can be found by finding the center position between these two points using the p and values. That is, Pc = (Pe+Pr)/
By performing the calculation in step 2 using the calculation circuit (4) under the control of the control circuit (c), it is possible to obtain the Pc position shown in FIG. 2(c) (step D).
? (4! If, for example, output to a printer and record.

In order to carry out such processing, the ITV camera (to) is moved to the optimum position, which is controlled by an XYZ table via a control circuit (4G) and an XYZ drive circuit (4G).

〔Effect of the invention〕

As explained above, according to the method of the present invention, since the position of the pattern is determined from the irradiation area of the electron beam for displaying the nokuturn, the detection error caused by the arrangement of the phosphors is minimized. Further improved detection accuracy can be obtained.

[Other sash examples]

In the above embodiments, a color-emitting phosphor was used as the display pattern, but other light-emitting phosphors may also be used.

It may be a white emitting phosphor or a plurality of emitting phosphors.

We have explained how to detect the center position of the signal pattern during adjustment, but the center of gravity in the electron beam irradiation area (
If the method is to find the center), use the above and other methods.

It can also be applied to automate the measurement of image distortion, tilt, etc. of color cathode ray tubes, and to detect the position of vertical line patterns of display patterns used.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of the method of the present invention,
Figures 2 (a), (b), and (C) are diagrams for explaining the center/position detection method in Figure 1, Figure 3 is a 70-chart for explaining the signal processing in Figure 1, and Figure 4 is a diagram for explaining the center/position detection method in Figure 1; Figures (a) (b)
5(C) is a diagram illustrating a conventional method for detecting the center position of an electron beam scanning raster, and FIGS. Agent: Patent attorney Noriyuki Chika and one other person Figure 1 7I Figure 2' Xj! Pc Xr' PI Pr Chiku'+m Hayabusa 4 Figure 5 (a) (Q). (b) (d)

Claims (2)

[Claims] (1) Display a desired pattern on a color cathode ray tube, take an image of this pattern with an imaging camera, and automatically adjust the center position in the scanning range of the electron beam of the color cathode ray tube to display the pattern on the imaged screen. When detecting, means for obtaining first and second summation values obtained by adding imaging output values for each scan in the vertical direction for the light-emitting phosphor rows at least at both end positions in the horizontal scanning direction of the pattern; means for determining the first and second ends of the irradiation range from the horizontal distance in the imaging screen of each phosphor array from which the added value is calculated; 1. A method for detecting the center position of an electron beam scanning raster on a color cathode ray tube display surface, comprising means for determining an intermediate position between sections. (2) The means for determining the intermediate position in the irradiation range of the electron beam is as follows: P_e=X_e−H_e・K_e and P_r
=X_r+H_r・K_r and P_c=(
A method for detecting the center position of an electron beam scanning raster on a color cathode ray tube display surface according to claim 1, further comprising means for determining P_e+P_r)/2. In the above formula, P_e...first end P_r in the imaging screen, second X_e...first horizontal end of the pattern X_r...
・〃Second〃 K_e, K_r...Constant P_c...Intermediate position in the electron beam irradiation range