JPS6022550B2 - Convergence color shift detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for automatically measuring coherence color shift of a color television receiver.

The measurement of the amount of color deviation of the subordinate components is carried out visually by the operator.

The method is to apply a white crosshatch pattern as shown in Figure 1 on the screen of the color television receiver to be inspected as shown in Figure 1. The amount of color shift and the amount of color shift in the horizontal direction of vertical lines are measured using a magnifying glass or the like. Here, 1 in the figure is a color TV screen, and 2 is a white crosshatch screen.
Patterns 3, 4, and 5 indicate red, green, and blue lines due to color shift. However, this amount of color shift is subjective because the light emitting state of each crab light body is investigated, and furthermore, it takes a long time to measure over the entire television screen.

Therefore, there has been a strong desire for a device that can automatically measure coherence in a short time and with high precision in place of visual inspection.
SUMMARY OF THE INVENTION An object of the present invention is to provide a detection device for automatically measuring the amount of color shift in coherence in a short time and with high precision, eliminating the drawbacks caused by the above-described conventional technique.

Next, the principle of the present invention will be explained.

The cross-hatch pattern for coherence testing is shown in Figure 1, but it is given as a vertical-main line pattern as shown in Figure 3. When the color shift part 6 is captured as a video signal waveform with an ITV black and white camera, the fourth
It will look like the figure. 7, 8, 9 in Figure 4 are red lines 3 in Figure 3
, the signal waveform corresponding to the green line 4 and the blue line 6, and the horizontal synchronization signal on the signal scanning line up to 10', tR, tG, t
B indicates the time interval from the horizontal synchronizing signal 10 to each signal waveform 7, 8, and 9. From this, the amount of color shift in coherence can be quantitatively measured as the difference between the time amounts tR, tG, and tB. In order to utilize this method for detecting vertical color shift occurring in the horizontal line pattern shown in FIG. 5, it is necessary to scan the detection camera in the vertical (vertical) direction. Figure 6 shows a block diagram of the deflection system of a general ITV black and white camera.
2 is a vertical driver, 13 is a vertical output device, 14 is a vertical deflection coil, 1 5 is a horizontal AFC, 1 6 is a horizontal driver,
17 is a horizontal output device, 18 is a horizontal deflection coil, 19 is a vertical synchronizing signal, and 20 is a horizontal synchronizing signal.

In the present invention, in order to electronically switch the vertical (vertical) and lateral (horizontal) deflections, a deflection circuit configuration shown in FIG. 7 is used. That is, 29 is a synchronization signal changeover switch, which switches and outputs the vertical synchronization signal 19 and the horizontal synchronization signal 20 from the switching signal 3 rivers. Therefore, the output 31 is a vertical synchronization signal or a horizontal synchronization signal, and the output 32 is a horizontal synchronization signal or a vertical synchronization signal. 21 is a vertical oscillator, 22 is a vertical driver, 23 is a vertical output device, 24 is a vertical deflection coil, 25 is a horizontal oscillator, 26 is a horizontal driver, 27 is a horizontal output device, 2
8 indicates a horizontal deflection coil.

However, at this time, simply switching the vertical and horizontal deflections will result in an unused portion of the image pickup tube due to the relationship between the aspect ratio of the camera and the aspect ratio of the TV screen to be inspected, reducing detection accuracy.

This state will be explained with reference to FIG. Figure 8a shows the scanning direction of the electron beam of a normal camera, where 33 in the figure shows the effective use surface of the camera tube, 34 the scanning direction of the electron beam of the camera tube, and 35 the scanning surface of the camera tube. , 36 indicate a color television screen to be inspected. If the vertical and horizontal deflections are simply switched as described above, the result will be as shown in FIG. 8b, resulting in an unused portion shown by diagonal lines. When the state shown in Fig. 8b is viewed on a monitor television, it becomes as shown in Fig. 9. Therefore,
When scanning in the vertical direction as shown in Figure 8c, it is necessary to shorten the length of the vertical scan and widen the length of the horizontal scan so that it looks like Figure 10 on the monitor TV. . In Figures 9 and 10, 1, 3, 4, 5 are the third
37 is a monitor television set, and 38 is a monitor television screen. As described above, the main point of the present invention is that when detecting a vertical color shift, the image pickup tube electron beam scan is set vertically, and when a horizontal color shift is detected, the image pickup tube electron beam scan can be switched to the horizontal direction. The purpose is to be able to detect coherence color shift in two directions with one camera.

FIG. 11 shows a circuit configuration of an embodiment of the present invention.

In the figure, 40 is a pattern generator for providing a white crosshatch pattern on the screen of the color television receiver 41 to be inspected, and 42 is a pattern generator for photographing the color shift of the crosshatch pattern on the screen of the color television receiver to be inspected. 43 is a video amplifier; 44 is a coherence detection circuit that detects the red, green, and blue lines of color shift on the designated scanning line; 45 is the red color shift from the horizontal synchronization signal point on the designated scanning line; This is a time measuring device that measures the time intervals up to the time when the , green, and blue lines are detected, and further calculates and outputs the difference between each time interval. 46 is a circuit for converting time difference data into length data, and 47 is a data printer.

Further, 48 is a program controller that controls the entire measurement procedure, etc., which sends a synchronization signal to the four pattern generators, sends a scanning direction switching signal to the ITV camera 42,
An instruction to designate the scanning line to be detected is given to the coherence detection circuit 44, a horizontal synchronization signal on the designated scanning line is sent to the time measuring device 45, and the data conversion circuit 46 and data printer 47 are also given an instruction to specify the scanning line to be detected. control signals, etc. Next, the operation of this device will be explained.

The scanning direction of the detection camera 42 is determined based on the scanning direction switching signal 301 from the program controller 48, and the color shift of the crosshatch pattern drawn on the TV screen to be inspected is photographed by the pattern generator 40. A video signal obtained by the camera 42 is amplified by a video amplifier 43 and input to a coherence detection circuit 44. Here, the peak position of the signal waveform as shown in FIG. 4 is detected, and the pattern position data (tR, tc, tB
) and time interval differences (tR-tG) and (tR-tB) are obtained as time data. This is further converted from a time amount (French S) to a length amount (m/m) by a conversion circuit 46, and printed out by a data printer 47. In the conventional visual measurement by an operator, subjectivity is involved in measuring coherence color shift, making quantitative measurement difficult. In addition, when the measurement points cover the entire television screen, it takes at least 5 to 6 minutes for one screen, and depending on the environmental conditions of the test, the strain on the eyes cannot be ignored. In the present invention, one monochrome ITV camera is used.
By switching the internal deflection circuit, the scanning direction of the image pickup tube electron beam can be switched vertically or horizontally, and the amount of color shift in the vertical and horizontal directions of the crosshatch pattern can be quantitatively measured (disassembled library 0.1 m/m). , and can be measured at high speed (about 1 second per screen).

Therefore, as the device becomes simpler, significant improvements in inspection accuracy, inspection time, and cost can be expected.

[Brief explanation of drawings]

Figures 1 to 3 each represent a color television screen to be inspected. Figure 1 shows the screen when a white crosshatch pattern is applied.
FIG. 2 shows an adjusted state with no color shift, FIG. 2 shows a state with color shift, and FIG. 3 shows a color shift state when a single vertical white line is provided as a pattern. FIG. 4 shows a detected video waveform obtained by capturing the TV screen of FIG. 3 with a monochrome ITV camera and sequentially developing a pattern in a single color. FIG. 5 shows the state of color shift when a horizontal white pattern is applied. FIG. 6 shows a block diagram of a deflection system of a general ITV monochrome camera. FIG. 7 shows a block diagram of a deflection system according to the present invention. Figures 8 to 10 are diagrams explaining the reason for the aspect ratio correction, and Figure 8 is a diagram showing the electron beam scanning state on the image pickup tube light receiving surface and the state of the light receiving surface when switching between vertical and horizontal modes. Figure 9 shows the state shown in Figure 8b displayed on the monitor TV screen;
The figure shows a scanned state obtained by correcting the deflection aspect ratio as shown in FIG. 8c and displayed on a monitor TV screen. FIG. 11 shows a block diagram of an embodiment of the invention. 40: Pattern generator, 41: Color television receiver to be inspected, 42: Black and white ITV camera, 43: Video amplifier,
44: Comparency detection circuit, 45: Time measuring device, 4
6: Conversion circuit, 47: Data printer, 48: Program controller. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] 1 A pattern generator for providing a white crosshatch pattern for convergence testing on the screen of a color television receiver to be tested; electronically switching the scanning direction of the image pickup tube electron beam between vertical and horizontal directions using an external instruction signal; The horizontal color shift of the crosshatch pattern on the screen is photographed by the horizontal scanning of the electron beam, and the vertical color shift of the crosshatch pattern is photographed by the vertical scanning of the electron beam. Get one black and white ITV camera; this IT
a convergence detection circuit that detects red, green, and blue color deviations on a designated scanning line of the output video signal of the V camera; a time measuring device that measures the time interval up to the detection point of the pattern, further calculates and outputs the difference between each time interval; a device that converts the data of the time interval difference into length data and displays it; The generator is synchronously controlled, the scanning direction of the image pickup tube electron beam of the ITV camera is controlled to be switched, the convergence detection circuit is controlled to designate a signal scanning line to be detected, and the time measuring device is controlled to detect a signal on the designated scanning line. a program controller that provides a synchronization signal and controls a measurement procedure to the data conversion and display device; an apparatus for automatically measuring the amount of convergence color shift of a color television receiver to be inspected;