JPS6039995A - Pattern distortion check device of crt display device - Google Patents

Abstract

PURPOSE:To improve both accuracy of inspection and efficiency of inspection by decreasing the number of divisions of an observed pattern at a division section so as to reduce the number of times of processing at a measuring section, a detection section, a comparison section and a discriminating section. CONSTITUTION:The number of divisions of the observed pattern at the division section 7 is decreased. Thus, the number of elements of each one dimensional arrangement stored in buffers 9, 12 and 13 is decreased, thereby decreasing the number of times of processings in the measuring section 8, the detection section 10, the comparison section 14 and the discrimination section 15. Thus, the accuracy of inspection and the efficiency of inspection are both improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an apparatus for inspecting screen distortion of a CRT (cathode ray tube) display device due to nonlinearity of an electron beam deflection circuit in a CRT (cathode ray tube).

(b) Background of the technology A CRT display device displays images such as characters on a CRT display screen by raster scanning a modulated electron beam based on image information such as characters to be displayed. In order to display clear and distortion-free images, we have installed various correction devices or adjustment devices, and we perform adjustments and inspections before shipping the product. This requires particular skill and time, and there is a desire to improve inspection accuracy and efficiency through automation.

(c) Conventional technology and problems There are conventional screen distortion inspection devices for CRT display devices.

A rectangle whose two sides are a line segment parallel to the main scanning direction and a line segment parallel to the sub-scanning direction of the CR, T display device is displayed as an inspection pattern, and the observation pattern obtained by displaying and observing this rectangle is displayed. The maximum displacement between a side and a straight line connecting both ends of this side, that is, adjacent vertices on the observed pattern, is calculated and compared with a predetermined reference value.

The position of the vertex on the observation pattern is determined by raster scanning the CRT display surface from each corner in a diagonal direction with respect to the main scanning direction, and determining the position of the vertex on the CRT display surface at the position where the scanning line first intersects with the observation pattern. Raster scanning in a diagonal direction with respect to the main scanning direction means scanning along step-like lines consisting of short line segments parallel to the main scanning direction and short line segments parallel to the sub-scanning direction. Therefore, in order to determine the position of the vertex with high precision, it is necessary to shorten the interval between raster scans in the diagonal direction and the length of each line segment constituting the stepped line. There was a problem in that it took a long time to complete the process, making it impossible to improve inspection efficiency.

(d) Object of the Invention An object of the present invention is to provide a screen distortion testing device for a CRT display device that can improve both testing accuracy and testing efficiency.

(e) Structure of the Invention The screen distortion inspection device for a CRT display device according to the present invention has a CR
a pattern generator that generates a test pattern including line segments parallel to the main scanning direction of the T display device and line segments parallel to the sub-scanning direction; and a pattern generator that observes the test pattern displayed on the CRT display device and generates an observed pattern. and a dividing unit that divides the observation pattern obtained by the observation unit into equally spaced grid lines parallel to the main scanning direction and equally spaced grid lines parallel to the sub-scanning direction to obtain divided observation patterns. and.

a measuring unit that measures the inclination of a line segment connecting end points of each divided observation pattern for each divided observation pattern obtained by the dividing unit; and a measuring unit that measures the slope of a line segment connecting end points of each divided observation pattern obtained by the dividing unit; a detection unit that detects a difference in slope of the line segment between adjacent divided observation patterns that exceeds a reference value, or a difference in slope of the line segment between adjacent divided observation patterns that exceeds a predetermined reference value; a comparison unit that compares the slope of each line segment connecting each end point of a divided observation pattern detected by the detection unit, the slope of each line segment connecting each end point of an adjacent divided observation pattern other than the divided observation pattern detected by the detection unit; The presence or absence of screen distortion of the CRT display device is tested by comparing the values.

(r) Examples of the Invention The gist of the present invention will be specifically explained below by referring to two examples.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In FIG. 1, 1 is a CRT display device to be inspected for screen distortion, and 2 is a line segment parallel to the main scanning direction of the CRT display device l. A pattern generator that generates a rectangular pattern whose two sides are line segments parallel to the sub-scanning direction as an inspection pattern, 3BC
The inspection pattern displayed on the RT display device 1 is observed and the observed pattern is j! 7 an industrial television camera (ITV) used as an observation unit; 4 a control unit that controls the position and zooming of the industrial television camera 3 and controls the observation area and observation field on the display surface of the CRT display device 1; is observed by industrial television camera 3.

6 is a detection unit that detects the end points of the observation pattern stored in the buffer 5; 7 is a detection unit that stores the observation pattern stored in the buffer 5 at equal intervals parallel to the main scanning direction of the CRT display device 1; A dividing section that divides the grid lines and equidistant grid lines parallel to the sub-scanning direction to obtain divided observation patterns, and the slope of the line segment connecting the end points of each divided pattern for each divided observation pattern obtained by the dividing section 7. 9- is a buffer that stores the slope of each divided observation pattern obtained by the measuring unit 8 in order from one α111 point side detected by the detecting unit 6 to the other end point side as a one-dimensional array. , 10 is the dividing part 7
Among the divided observation patterns obtained, the slope of the line segment connecting the end points exceeds a predetermined reference value, or the difference in the slope of the line segment between adjacent divided observation patterns exceeds a predetermined first reference value. a detection unit that detects a divided observation pattern corresponding to a vertex of the inspection pattern by detecting a peak that exceeds the peak of the inspection pattern;

Reference numeral 11 designates a one-dimensional array stored in the buffer 9 as a one-dimensional array corresponding to a line segment parallel to the main scanning direction (X coordinate axis) of the inspection pattern using the divided observation pattern corresponding to the vertex of the inspection pattern obtained by the detection unit 10. a conversion unit that converts the array X into a one-dimensional array Y corresponding to a line segment parallel to the sub-scanning direction (Y coordinate axis) of the inspection pattern; 12 is a buffer that stores the one-dimensional array X obtained by the conversion unit 11; 13 is a one-dimensional array Y obtained by the conversion unit 11
14 is a comparison unit that compares the slope values of each line segment connecting the respective end points of adjacent divided observation patterns excluding the divided observation pattern detected by the detection unit 1O, and determines the difference; 15 is a comparison unit This is a determination unit that determines whether the difference in slope obtained by step 14 exceeds a predetermined second reference value.

FIG. 2 shows a rectangular inspection pattern [a] generated by the pattern generator 2 and an example (b) of a display pattern obtained when the CR7 display device 1 has distortions in both the main scanning direction and the sub-scanning direction.

The industrial television camera 3 is controlled by the control unit 4 and is connected to a CRT.
The upper left quarter of the R7 display device 1 is observed, and an observation pattern as illustrated in FIG. 3 is stored in the buffer 5.

The detection unit 6 detects the end points A and B by scanning the outer periphery of the observation pattern stored in the buffer 5 as follows: a-=b-b-+c-c-*d.d-+a.

The dividing unit 7 divides the observation pattern stored in the buffer 5 into a fourth
As shown in the figure, AC-C
D -DE -EF -FG -Gll・III・IJ
- Divide into JK and L and LB.

The measurement unit 8 measures the inclination of a line segment connecting the end points of each divided observation pattern, for example, a line segment indicated by a dotted line for the old divided observation pattern, with respect to the X coordinate axis or the Y coordinate axis,
8C-CD -DE・BP -FG -GH・III
= IJ - JK - KL and LB are stored in the buffer 9 as a one-dimensional array in this order.

As illustrated in FIG. 4, in general, in the divided observation pattern III corresponding to the apex of the inspection pattern, the slope of the line segment connecting each end point changes rapidly, or , the direction of which changes.

Therefore, the detecting unit 10 detects that the slope of the line segment corresponding to each of the divided observation patterns exceeds a predetermined reference value, or that the difference in the slope of the line segment between adjacent divided observation patterns By detecting those exceeding the value, it is possible to detect the divided observation pattern I11 for the vertex of the test pattern.

As a result, the one-dimensional array stored in buffer 9 is
The conversion unit 11 converts the observation pattern into one divided observation pattern AC/CD.
It is converted into a one-dimensional array X corresponding to DE-Ko-FG and Gll and a one-dimensional array Y corresponding to the one-division observation pattern IJ-JK-KL and LB, and stored in buffer I2 and buffer 13, respectively.

Comparison unit 14 compares one-dimensional array X and one-dimensional array Y stored in buffer 12 and buffer 13, respectively.
The discriminating unit 15 calculates the difference between adjacent elements of
The presence or absence of screen distortion of the CRT display device is determined by comparing the difference between the slope values of the respective line segments obtained in step 4 with a predetermined second reference value.

Inspection of the end points (A and B, not shown in FIG. 3) of the observation pattern by the detection unit 6 can be carried out in an extremely short time and at high speed by scanning twice in the main scanning direction and twice in the sub-scanning direction.

In general, the screen distortion of a CRT display device often appears as shown in FIG. 2(b) for a rectangular inspection pattern as shown in FIG. 2(a). When the number of grid lines is increased, the difference in slope values between line segments connecting end points of adjacent divided observation patterns decreases. Therefore, the smaller the number of grid lines used in the dividing section 7, the easier it is to detect screen distortion.

That is, by reducing the number of divisions of the observation pattern in the two-division section 7, the number of elements of each -dimensional array stored in the buffer 9, buffer 12, and buffer 13 is reduced, and accordingly, the number of elements of each -dimensional array stored in the buffer 9, buffer 12, and buffer 13 is reduced. 10. The number of times of processing in the comparing unit 14 and the determining unit 15 is also reduced,
Therefore, both inspection accuracy and inspection efficiency can be improved.

In the above embodiment, the presence or absence of screen distortion of a CRT display device is determined by comparing the difference in the slope value of each line segment connecting the respective end points of adjacent divided observation patterns excluding the apex of the inspection pattern with a predetermined reference value. However, as another example, the presence or absence of screen distortion of a CRT display device can be determined based on changes in the direction of inclination of each line segment connecting the end points of adjacent divided observation patterns excluding the apex of the inspection pattern. You can also.

(g) Detailed Description of the Invention As described above, according to the present invention, it is possible to obtain a screen distortion inspection device for a CRT display device that can improve both inspection accuracy and inspection efficiency.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention;
Figures (al and b) show examples of inspection patterns and display patterns, Figure 3 shows examples of observation patterns, and Figure 4 shows explanatory diagrams regarding divided observation patterns. 3 is an industrial television camera, 7 is a dividing section, 8 is a measurement section, 10 is a detection section, 14 is a comparison section, and 15 is a separation section. Tei + country

Claims (2)

[Claims] (1) C-RTT display device A pattern generator that generates a test pattern including line segments parallel to the main scanning direction and line segments parallel to the sub-scanning direction, and observation of the test pattern displayed on the CRT display device. an observation unit that obtains an observation pattern; and an observation unit that divides the observation pattern obtained by the observation unit into grid lines at equal intervals parallel to the main scanning direction and grid lines at equal intervals parallel to the sub-scanning direction. a dividing unit that obtains a divided observation pattern, a measuring unit that measures the slope of a line segment connecting the end points of each divided observation pattern for each divided observation pattern (η) obtained by the dividing unit, and a dividing observation pattern obtained by the dividing unit. a detection unit that detects a line segment connecting end points of which a 1/1 slope exceeds a predetermined reference value or a difference in slope of the line segment between adjacent divided observation patterns exceeds a predetermined reference value; , a comparison unit that compares the slope of each line segment connecting each end point of the adjacent divided observation pattern excluding the divided observation pattern detected by the detection unit. A screen distortion inspection device for a CRT display device, characterized in that the presence or absence of screen distortion in a CRT display device is inspected by comparing the slopes of each line segment connecting each end point of a divided observation pattern. (2) The comparison unit compares the slope values of each line segment connecting end points of adjacent divided observation patterns other than the divided observation pattern detected by the detection unit. A screen distortion inspection device for a CRT display device according to scope 1.