JPH04101324A - Convergence measuring method for color image receiving tube - Google Patents

Abstract

PURPOSE:To shorten the measuring time by photographing the white light measuring image with a solid element color camera on the screen of a color image receiving tube, dissolving into R, G, B, converting into digital image signals, and calculating the misconvergence amount by a computer. CONSTITUTION:The screen 4 of a color image receiving tube reflects a white light measuring image, and this measuring image is photographed by a solid element color camera 1 and dissolved into R, G, B analog image signals using filters built in the camera 1. Then these R, G, B analog signals are converted into digital signals by an A/D converter, and a comparator takes out the largest among each color digital signals. The taken-out three signals are accommodated in a video recorder, and the accommodated data is subjected to a processing with a computer 3 for calculation of the positions of the R, G, B measuring images, and the misconvergence amount is determined. This shortens the measuring time and enhances the measuring accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for measuring convergence of a color picture tube.

<Prior Art> One of the reasons why it is difficult to see the screen of a color picture tube such as a color television is that the images of the three primary colors of red, green, and blue light are not superimposed.

In order to improve this, the three electron beams emitted from the electron gun must be made to converge on the screen no matter where on the screen they are deflected.

The overlapping of these three beams is called beam convergence or simply convergence.

Therefore, in order to display a clear image, it is necessary to measure the presence or absence of this convergence shift.

FIG. 8 shows a conventional method for measuring convergence.

That is, measurement lines 5 of the three primary colors of light, red, green, and blue, are sequentially projected onto the tube surface 4 of a color picture tube, and these measurement lines 5 are
A CD (solid-state device) monochrome camera 6 takes images of each color three times.

This method then processes these imaging data using a video recorder, calculates the positions of the three color measurement lines 5, and calculates the amount of positional deviation.

<Problems to be Solved by the Present Invention> The conventional convergence measuring method described above has the following problems.

<B> Since a monochrome CCD camera is used, the red, green, and blue measurement lines 5 must be imaged three times for each negative color.

Therefore, the measurement time is long, which is inconvenient for convergence measurement of mass-produced color picture tubes.

<Exposure> Furthermore, since the red, green, and blue measurement lines 5 cannot be measured at the same time, measurement errors occur due to time differences.

For example, this may be caused by vibrations on the floor or shaking of the object to be measured itself.

<Objective of the present invention> The present invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for measuring convergence of a color picture tube that can shorten measurement time and improve measurement accuracy. With the goal.

<Means for solving the problems> That is, the present invention projects a measurement image of white light on the tube surface of a color picture tube, captures this measurement image with a solid-state color camera, and captures the measurement image with a solid-state color camera built in the solid-state color camera. A filter separates the white light into three-color analog image signals of red, green, and blue. Next, an A/D converter converts each color analog image signal into a digital image signal, and a comparator converts the white light into digital image signals. , extract only the largest signal from each digital image signal, store these three extracted signals in a video recorder, process these stored data with a computer, and create the measurement image of the three colors. This is a color picture tube convergence measurement method that calculates the position of the color picture tube and calculates the amount of positional deviation.

<Description of the present invention> The present invention will be explained in detail below.

<B> Structure of the entire measuring device As shown in FIG.
It consists of a D (solid-state element) color camera 1, comparison/storage device 2, and computer 3.

<mouth> CCD color camera As shown in FIG. 2, the CCD color camera 1 includes a filter 11 that separates white light into analog image signals of three colors: red (R), green (G), and blue (B). Built-in.

<C> Comparison/Storage Device The comparison/storage device 2 includes a converter 21 that converts an analog image signal into a digital image signal, a comparator 22, and a video recorder 23.

Here, the role of the comparator 22 is to erase the image signals of the other two colors, since the digital image signals of each color are mixed with the image signals of the other two colors, and to generate the image signal of the original color. This is a device for transmitting only the video to the video recorder 23.

<2> Measurement method First, as shown in FIG. 1, a white light measurement image is projected onto the tube surface 4 of a color picture tube.

For example, a grid-like measurement line 5 is projected.

Next, this measurement line 5 is imaged by the CCD color camera 1.

As shown in FIG. 2, a filter 11 built into the CCD color camera 1 separates the white light into analog image signals of three colors: red, green, and blue.

Next, by the A/D converter 21 of the comparison/storage device 2,
Converts analog image signals of each color to digital image signals.

Furthermore, the comparator 22 erases the image signals of the other two colors mixed into the digital image signal of each color, and extracts only the largest image signal of the original color.

These three extracted signals are stored in the video recorder 23, respectively.

Then, these stored data are processed by the computer 3, the positions of the three color measurement lines 5 are calculated, and the amount of positional deviation is calculated.

<Action of the present invention> By using the comparator 22 as described above, the present invention can expect the following effects.

That is, since the wavelengths of red, green, and blue are different, the filter 11 used for color separation of white light has a function of passing a certain wavelength.

However, the wavelengths are not completely different (as shown in Figure 3, there are some overlapping parts, and it is not possible to completely separate them.

Furthermore, since various types of light are diffused from the phosphor of the cathode ray tube itself, blue light may sometimes penetrate into the red portion, as shown in FIG.

As a result, other colors are mixed with data that should originally be a negative color, and data with mixed colors as shown in FIGS. 5 to 7 are stored.

FIG. 5 shows green in blue data, FIG. 6 shows blue in green data, and FIG. 7 shows green and blue in red data.

Therefore, it is not possible to accurately calculate the position and positional deviation of the measurement line 5.

Therefore, in the present invention, the image signals of each color are transmitted to the video recorder 2.
3, an operation is performed to extract only the largest signal among the mixed image signals through the comparator 22.

In other words, since the mixed image signals of the other two colors are smaller than the original color image signal, by erasing these small signals, only the largest original color signal can be extracted. .

Therefore, only the original color data can be stored in the video recorder 23, and the position and positional deviation of the measurement line 5 can be calculated accurately.

Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

<B> Positional deviation can be calculated by simultaneously measuring three color measurement lines of red, green, and blue.

Therefore, the measurement time can be reduced compared to the conventional method.

In addition, since there is no measurement error due to time difference as in the conventional method, it is possible to improve measurement accuracy.

<C> Convert analog image signals to digital image signals,
After digitizing, the position of the measurement line is calculated.

Therefore, the measurement accuracy is improved compared to the case where the position of the measurement line is calculated using the analog image signal.

[Brief explanation of the drawing]

Figure 1: Explanatory diagram of the entire measuring device Figure 2: Flowchart of the entire measuring device Explanation Kogyo 3.4
Figure: Explanatory diagram showing the overlap of the wavelengths of the three primary colors. Figures 5 to 7: An explanatory diagram of the state in which stored data is mixed. Figure 8: An explanatory diagram of the prior art.

Claims (1)

[Claims] (1) A measurement image of white light is projected onto the tube surface of a color picture tube, this measurement image is captured by a solid-state color camera, and the white light is divided into red, green, and blue by a filter built into the solid-state color camera. Next, an A/D converter converts each color analog image signal into a digital image signal, and a comparator selects the largest one of each digital image signal. extracting only the signal, storing the three extracted signals in a video recorder, processing these stored data with a computer, calculating the position of the three color measurement images, and calculating the amount of positional deviation, Method for measuring convergence of color picture tubes.