JPS62198031A - Color convergence automatic adjusting device - Google Patents

Abstract

PURPOSE:To improve the accuracy and efficiency of the color convergence adjustment, by correcting automatically the convergence in the negative feedback to unify the central position of phosphor dot group, and correcting and storing the result in a PROM for digital convergence. CONSTITUTION:Only R spots in a cathode-ray tube are displayed at the center of the display screen, and an image processor 2 computes the central position from the positions of phosphor dots in the spot to be observed. In the same manner, the image processor 2 computes the central position of the phosphor G dot group when the CRT displays only G. The distance of the both central positions of R and G, that is, the color misconvergence, is computed. When the color misconvergence is out of the standard value, the image processor 2 computes the condition to correct the beam convergences of R and G, and the RAM 6 is renewed through a system control 3 and a memory control 5. Furthermore, the computing and correcting of the misconvergence between G and B are also carried out in the same manner.

Description

[Detailed Description of the Invention] [Summary] One beam spot located at a predetermined position on the display screen of a digital convergence type color CRT display device is imaged with a camera, and from the video output signal, the red color in that spot is By calculating the center positions of the phosphor dot groups for each of the three primary colors of green and blue, automatically correcting the convergence using negative feedback so that the three center positions match, and correcting and storing the results in the digital convergence FROM. , to improve the accuracy and efficiency of color convergence adjustment.

[Industrial application field]

TECHNICAL FIELD This invention relates to color CR7 display devices, and more particularly to automated methods for digital convergence adjustment.

Color CRTs for display use a shadow mask method in which three types of phosphor dots, R (red), G (green), and B (blue) are individually irradiated with electron beams to cause them to emit light. If the relationships among the holes, the electron beams to pass through the holes, and the positions of the corresponding phosphor dots of each color do not match, color shift will occur. This color shift varies depending on the position on the screen, and in order to correct it, convergence is corrected for every three beams at each screen name position, for example, 25 divided positions.

A digital convergence method is used in the high-precision color graphic CR7 display device, but in this method, the conditions for convergence at the above-mentioned screen position are digitized and PRO? Good convergence is obtained over the entire screen by storing the conditions in 1 (writable read-only memory) and reading out the conditions when scanning the screen to perform convergence.

With the recent development of higher resolution and lower prices of color display devices, there is a demand for a highly accurate and efficient adjustment method that does not depend on the personal skill of the device adjustment operator. There is.

[Problems to be solved by the prior art and the invention] In the conventional digital convergence adjustment work, an operator uses a magnifying glass or the like to visually observe color shifts at, for example, 25 locations. , the contents of the convergence memory were corrected by inputting convergence adjustment values from an input device such as a keyboard, but not only did it take a long time to make the adjustment, but the adjustment results varied greatly from person to person, and the operator There was a problem that the eyes were very tired.

The present invention was invented in view of these points.
The purpose of this invention is to provide an automatic color convergence adjustment method that allows highly accurate and highly efficient adjustment with a simple configuration.

[Means for solving problems]

Accordingly, the present invention provides an electronic camera that magnifies and images one spot of an electron beam of a CRT of a display device to be adjusted, and a video output signal of the electronic camera that captures R, G, and
, B, and an image processing section that calculates the center position of each of the three primary color phosphor dot groups and calculates a convergence correction value necessary for matching the three center positions for each of the three primary colors.

[For production]

Taking a 20-inch shadow mask type CRT (cathode ray tube) as an example, the hole pitch of the shadow mask is 0.25~
The diameter of the beam spot corresponding to one dot of image information is about 2.5 times that.
That is, it is set to 0.7 to 0.81.

In the color convergence adjustment, a spot on the CRT is brought to a point in the center of the display screen to be adjusted, magnified and imaged by a camera, and the spot is first displayed in R only.

When the electronic camera magnifies and captures an image of this spot, several fluorescent R dots are found within the spot.

The image processing section performs image processing on the video output signal of the camera to calculate the center position of the group of phosphors 8171.

Next, the beam is switched to only G, and similarly to R, the center position of the G phosphor dot group is calculated.

The image processing unit further processes these observed and calculated R and G.
The difference between the center positions of both groups, that is, the color shift is calculated. If the calculated color shift value is outside the standard, the corrected convergence conditions for the R and G beams are calculated, output, and sent to the digital convergence condition setting RA conventionally provided in the convergence adjustment device. Rewrite. When the CRT operates under this convergence condition,
This correction operation continues automatically until the color shift falls within the standard.

When this color shift falls within the standard, the phosphor 81 under that condition
Color shift is similarly calculated and corrected between the center position of the 71st group and the center position of the fluorescent B dot group, which is measured and calculated in the same way.

The above adjustment procedure is similarly performed for G-8.

The convergence conditions that have been adjusted are rewritten in the FROM in the wave adjustment and display device using a conventional method.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in the drawings.

FIG. 1 is a block diagram showing the configuration of one embodiment. In the figure, 1 is an electronic camera, 2 is an image processing section, 3 is a system control section, 4 is a console, 5 is a memory control section,
6 is a RAM, 7 is a FROM writing section, 8 is a display device to be adjusted, 9 is a PROM%10 is a D/A converter, 12 is a convergence adjustment coil driver, 12 is a convergence adjustment coil, 13 is a CRT, 14 is a camera The positioning mechanism 18 is a positioning mechanism control section.

The camera 1 takes an image while enlarging a predetermined position on the screen of the CRT 13 of the display device 8 to be adjusted, and outputs a video signal to the image processing section 3 . First, an R-only spot is displayed on the CRT at the center of the display screen, and at this time the image processing section 2 calculates the center position from each position of the fluorescent R dot within the observed spot.

Further, the image processing section 2 calculates the center position of the group of fluorescent G dots when the CRT is displaying only G, and calculates the distance between the center positions of both R and G, that is, the color shift. Specifically, the enlarged image signal of one spot during monochromatic light emission is converted into a data signal, developed on the image memory, and the center of the spot can be calculated from the coordinate position data corresponding to the outer diameter of the spot image. .

If the color is blurred or outside the standard value, the image processing section 2 calculates the conditions to correct the R and G beam convergence, and stores it in the RAM 6. via the system control section 3 and memory control section 6. Rewrite.

This negative feedback operation is automatically repeated until the deviation falls within the standard value.

When this deviation is within the standard value, or if it is within the standard value from the beginning, the center position of the phosphor R dot group and B
The color shift from the center position of the group of phosphor dots is observed, calculated, and corrected, and the shift is similarly calculated and corrected between G and B. These modifications will interfere with each other to some extent, so check and modify them repeatedly.

The system control unit 3 supervises the entire system, and feeds the result data from the image processing unit to the memory control unit 5 and gives instructions for moving the camera position.The memory control unit 6 receives data from the system control unit 3. The corrected convergence conditions are received and stored in the RAM 6 in association with the measured position. The RAM 6 inputs the stored new convergence conditions to the D/^ converter 10 in place of the ROM 9 in the device, and passes through the driver 11 to a predetermined convergence coil, in the figure B beam coil 12-B. Drive. Note that illustration of the R and G beam circuits is omitted.

When the convergence adjustment at the center of the screen falls within the standard value, the camera is moved to another predetermined adjustment location divided into 25 parts, for example, and the above adjustment procedure is repeated. Note that although convergence conditions are set independently for each adjustment location, in reality they influence each other to some degree, so even after all adjustment locations are completed, the deviation confirmation measurement is performed again.

The camera positioning mechanism 14 and the positioning mechanism control section 15 move the camera position, and are effectively used to automatically perform convergence adjustment at all positions. A console 4 is used for interaction between the adjustment device and its user.

The camera 1 is a known commercially available camera, and the image processing section 2 is a digital logic circuit that can be easily constructed using well-known conventional technology and inexpensive components.

As can be seen from the above explanation, color convergence adjustment requires repeated measurements, corrections, and result confirmations at a large number of locations. Therefore, it can be understood that the automatic adjustment based on negative feedback correction of color shift according to the present invention is extremely effective in making adjustment more accurate and efficient.

〔Effect of the invention〕

In the traditional method, a skilled worker uses a magnifying glass to
Even after several tens of minutes of adjustment, individual differences remained, but as described above, with the method of the present invention,
Completely automatic, uniform, and highly accurate adjustment can be achieved with a number of man-hours to several tens of minutes compared to the conventional method, and its industrial effects are extremely large.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the invention. In the figure, 1 is the camera, 2 is an image processing unit, 8 is a display device to be adjusted. Figure 1

Claims (1)

[Scope of Claims] A convergence adjustment device provided outside a color cathode ray tube display device using a digital convergence method that stores color convergence conditions in a digital memory and calls the conditions during screen scanning to perform convergence. An electronic camera 1 magnifies and images the spot of the electron beam of the adjusted cathode ray tube, and from the video output signal of the electronic camera, determines the center position of each of the phosphor dot groups of each of the three primary colors of red, green, and blue within the spot. An automatic color convergence adjustment device comprising an image processing unit 2 that calculates convergence correction values necessary for matching the three center positions for each of the three primary colors.