JPH01183031A - Inspection device for fluorescent screen - Google Patents

Abstract

PURPOSE:To digitize the mixing color of phosphors of plural colors and the like to make it possible to evaluate objectively by separating an image on a fluorescent screen in the colors of phosphors respectively, and comparing the luminous positions and the luminous areas of the phosphors of the colors. CONSTITUTION:An image on a fluorescent screen is output to an image processing device 3 as a video signal. The device 3 separates the signal input from a color video camera 2 into three colors, red, green, and blue by a camera control unit 6, and the signals of the separated three colors, red, green, and blue are A/D converted, output to signal memory units 7R, 7G, and 7B responding to each color, and recorded on the respective memories. Then, while the records are input to an operation unit 8, they are input to a color monitor TV 9 when necessary. The operation unit 8 carrys out the operation depending on the input signals, and finds the areas and the centers as to the luminous points of the luminous phosphors respectively in the coordinates within the image screen. By comparing the luminous points and the luminous areas of the phosphors of the colors respectively, the mixing color and the like can be digitized.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to an inspection device for the phosphor screen of a color picture tube, and in particular, it is capable of objectively evaluating the color mixture of phosphors of each color. related to things.

(Prior Art) For example, as shown in FIG. 6, the phosphor screen on the inner surface of the panel of a three-color picture tube consists of three color phosphors R, red, green, and blue.
,,G,,B spots are arranged regularly and a black light absorption band is provided between them, but the actual phosphor R,
In the coating state of G,,B, three color phosphors R-,,,G
A phenomenon called color mixing occurs in which colors , , and B are mixed into positions of other colors different from their original positions.

For example, if you look at only the blue phosphor B, it will look like the one shown in Figure 7, but if you enlarge it, you will see that the blue phosphor R is located at the position of the other color phosphor R, as shown in Figure 8. Phosphor B may be mixed in, or blue phosphor B may be missing inside or around the original blue phosphor B (phosphor R1G of another color may be mixed into the missing area, resulting in (often).

For this reason, after applying phosphors R, G, and B to the inner surface of the panel,! The light surface is inspected, but the conventional fluorescent inspection method uses an ultraviolet lamp to inspect the phosphor R.
,G,B are excited to emit light, and phosphors of each color R,,G,
The luminescence state of B was visually evaluated by an operator using a microscope with a magnification of 50 to 100 times.

(Problem to be solved by the invention) However, in the above-mentioned visual evaluation by workers, there are individual differences in the evaluation, and in order to ensure eye safety, strong ultraviolet rays are irradiated onto the fluorescent screen. Therefore, the luminance of the phosphors R1G and R1B was insufficient, and the evaluation error became even larger.

The present invention has been developed in view of these points, and when inspecting the phosphor screen of a color picture tube, eliminates the harmful effects of ultraviolet rays on the human body while accurately quantifying the color mixture of phosphors of each color and objectively. This is an attempt to make a highly accurate evaluation.

(Structure of the Invention) (Means for Solving the Problems) The phosphor screen inspection device of the present invention irradiates ultraviolet rays onto the phosphor screen formed on the inner surface of the panel of a color picture tube to detect multiple colors of fluorescent light on the phosphor screen. An ultraviolet irradiation device that excites the body, an optical system that magnifies the phosphor screen emitted by the ultraviolet irradiation device, a color camera that images the phosphor screen magnified by this optical system, and a phosphor screen that is imaged by the color camera. The apparatus is equipped with an image processing device that separates the image of each color of phosphor and compares the light emitting position and light emitting area of the phosphor for each color.

(Function) The phosphor screen inspection device of the present invention can quantify and objectively evaluate the color mixture of phosphors of each color by comparing the light emitting position and light emitting area of each color of phosphor. can.

(Embodiments) Several embodiments of the phosphor screen inspection apparatus of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment, P is a panel of a three-color picture tube to be inspected in this embodiment, and 1 is an optical system that magnifies a phosphor screen formed on the inner surface of the panel P into a mark by about 5 times. A color video camera 2 as a color camera is connected to this microscope 1, and this color video camera 2 is a microscope as a system.
An image processing device 3 is connected to.

4 is an ultraviolet irradiation device; this ultraviolet irradiation device 4
The emission wavelength is mainly 1500mII below 370nm.
An ultra-high pressure mercury lamp or a xenon lamp having an output of 1/ct1 or more is built in, and the generated ultraviolet rays are transmitted through an optical fiber 5 made of quartz to the part of the fluorescent screen of the panel P that is to be magnified by the microscope 1. It is designed to illuminate from the side.

In this first embodiment, the angle of irradiation of the ultraviolet rays onto the phosphor screen of the panel P is inclined by about 30 degrees with respect to the optical axis of the objective lens 1a of the microscope 1.

The image processing device 3 includes a camera control unit 6
and three signal memory units 7R, 7G, and 7B corresponding to the three color phosphors R, G, and B to be inspected in this embodiment.
and an arithmetic unit 8, and a color monitor television 9 is also provided.

Furthermore, FIG. 2 shows a modification of the first embodiment shown in FIG. 1, and by using a dark field type microscope 1,
Ultraviolet rays generated by the ultra-high pressure mercury lamp or xenon lamp of the ultraviolet irradiation device 4 are introduced into the microscope 111 and reflected by a half mirror in the microscope 1, so that the portion of the fluorescent screen of the panel P that is magnified by the microscope 1 It is designed to irradiate

In this modification as well, the angle at which the ultraviolet rays are irradiated onto the phosphor screen of the panel P is tilted at about 30 degrees with respect to the optical axis of the objective lens 1a of the microscope 1, and moreover, the angle at which the ultraviolet rays are transmitted is Lenses etc. are made of quartz.

3 shows a second embodiment, which is a combination of the first embodiment shown in FIG. 1 and its modification shown in FIG. The microscope 1 is placed on the outside surface of the panel P, whereas the microscope 1 is placed on the outside surface of the panel P.The other configuration is the first embodiment shown in FIG. There is no difference.

Furthermore, FIG. 4 shows a third embodiment, which is a combination of the microscope 1 and the color video camera of the first embodiment shown in FIG. 1 or its modified example shown in FIG. 2 and the ultraviolet irradiation device 4 are attached to the two-axis X-Y stage 10,
Handles 10x and 10y of this X-Y stage 10
By operating the microscope 1, color video camera 2, and ultraviolet irradiation device 4, the microscope 1, color video camera 2, and ultraviolet irradiation device 4 can be moved to any position on the fluorescent screen of the panel P.

As a modification of the third embodiment, it is conceivable that the X-Y stage 10 is driven by a motor or the like instead of the manual handles 10x and 10y.

Furthermore, the color video camera 2 of the modification of the first embodiment shown in FIG. 2, the second embodiment shown in FIG. 3, and the third embodiment shown in FIG. , an image processing device 3 is connected as in the first embodiment shown in FIG.

Next, the effects of these embodiments and their modifications will be explained.

First, aim the objective lens 1a of the microscope 1 at a desired position on the phosphor screen of the panel P, operate the knob 1C while looking through the eyepiece 1b to focus on the phosphor screen, and then use the ultra-high pressure mercury The portion to be magnified is irradiated with ultraviolet light generated by a lamp or a xenon lamp using a microscope 1.

Then, the three color phosphors R, G, and E on the phosphor screen are exposed to ultraviolet light.
3 is excited and emits light, and the emitted phosphor screen is magnified approximately 5 times with a microscope 1 and imaged with a color video camera 2, and the image of the phosphor screen as shown in FIG. 6 is imaged as a video signal. Output to the processing device 3.

The image processing device 3 uses the camera control unit 6 to convert signals input from the color video camera 2h1 into red, green, and
The signal is separated into three color signals of blue, and the separated three color signals of red, green, and blue are A/D converted and then input to the signal memory units 7R, 7G, and 7B corresponding to each color. Recording is performed on each frame memory, and the recording on this frame memory is output to the arithmetic unit 8, and if necessary, the recording on the frame memory is D/A converted and then output to the color monitor television 9. do.

Here, to explain the magnification rate of the phosphor screen, for example, in order to capture a mixed color of about 5 ttm, the size of the imaging surface of the color video camera 2 is 8 x 6 m, and the number of pixels is 50.
If 0x 500, single-tube color video camera 2
In this case, an optical magnification of about 5 times is required, and for the three-tube color video camera 2, an optical magnification of about 2 times is sufficient.

Then, the calculation unit 8 performs calculations based on the input signal. For example, in the case of the signal memory unit 7B corresponding to blue, an image of only the blue phosphor B as shown in FIG. 7 is recorded. Based on this, pixels are classified by brightness and the distribution of the number of pixels per brightness is determined, as shown in FIG.

In this Figure 5, the mountain on the left corresponds to the black part that does not emit light, the mountain on the right corresponds to the part of the blue phosphor B that emits light, and the arithmetic unit 8 corresponds to the black part that does not emit light. Binarization level a is set in the center of the valley between the peak corresponding to the part corresponding to the part of blue phosphor B that is emitting light, and the pixel darker than a is set as O11, and the pixel darker than a is set as O11. Also, so-called binarization is performed in which bright pixels are set to 1''.

Regarding this binarization, in addition to the method of automatically setting the level a in the arithmetic unit 8 and performing the binarization, there is also a method in which the three color signals of red, green, and blue separated by the camera control unit 6 are used. , after A/D conversion, when inputting to signal memory units 7R, 7G, and 7B corresponding to each color, binarization is performed using level a previously set by another means, 0 corresponding to the part that is not emitting light
There is also a method of inputting the signal ``'' and the signal 1'' corresponding to the light emitting part to the signal memory units 7R, 7G, and 7B.

Based on this binarized image information, the arithmetic unit 8 calculates the area of each light spot of the emitted phosphor B and the center area within the screen, as shown in the following table. Find the coordinates of.

(See next page below) The arithmetic unit 8 also performs similar processing on the signals recorded in the signal memory unit 7G corresponding to green and the signal memory unit 7R corresponding to red.

Then, the light spot information as shown in the above table obtained through such processing includes phosphors R and G.

Information on a normal case where B emits light in its original position, and a mixed color case where phosphors R, G, and B are mixed in and emit light in a square color position different from their original position. This means that the information on each light spot is mixed, but these can be easily distinguished by comparing the information on each light spot.

In other words, among the large number of light spots mentioned above, the light spot with a relatively large area is naturally considered to be a normal light spot in its original position.
Moreover, the positional relationships of the light spots of the three colors are set as shown in FIG. 6, and for example, the positional relationship of the light spots of blue phosphor B is
As shown in the figure, we focus on the light spots with large areas, and from the mutual positional relationship of the large light spots, we distinguish between the normal light spots in their original positions and the mixed color light spots mixed in at the positions of other colors. , can be digitized and stored, this processing can be performed by the arithmetic unit 8, and this can be outputted to the color monitor television 9 for display.

In addition, the calculation unit 8 distinguishes between normal light spots in their original positions, those with areas above the standard and those below the standard, and detects those where the original phosphors R, G, and B are missing. (In many cases, the phosphor LG of another color is mixed in the colored portion) can be digitized and restored, and this can be output to the color monitor television 9 and displayed.

In the previous explanation, before irradiating ultraviolet light with the ultraviolet irradiation device 4, the focus of the microscope 1 was adjusted while looking through the eyepiece lens 1b, but in this embodiment, since there is a color monitor television 9, Without looking into the eyepiece 1b, while irradiating ultraviolet rays with the ultraviolet irradiation device 4, look at the color monitor television 9 and use the microscope &! 11 focusing can be performed.

[Effects of the Invention] As described above, according to the present invention, by comparing the light emitting positions and light emitting areas of the phosphors of each color in the color picture tube, it is possible to quantify the color mixture of the phosphors of each color. Furthermore, since it is possible to eliminate the harmful effects of ultraviolet rays on the human body, it is possible to use ultraviolet rays of optimal intensity, and the quantification is accurate, resulting in highly accurate evaluation.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the phosphor screen inspection apparatus of the present invention, and FIG. 1 is a side view showing an outline of the first embodiment;
Figure 2 is a front view showing an outline of the modified example, and Figure 3 is a front view of the modified example.
FIG. 4 is a front view showing an outline of the third embodiment, and FIG. 5 shows the brightness and number of pixels for each color of phosphor to explain the image processing method. Distribution map, No. 6
The figure shows a phosphor screen, FIG. 7 shows a phosphor screen in which only one color of phosphor is emphasized, and FIG. 8 shows a mixture of colors of phosphors. P... Panel, R, 'G, B... Fluorescent material, 1... Microscope as an optical system, 2... Color video camera as a color camera, 3... Image processing device, 4... Ultraviolet irradiation device.

Claims (1)

[Claims] (1) An ultraviolet irradiation device that irradiates the phosphor screen formed on the inner surface of the color picture tube panel with ultraviolet rays to excite multiple color phosphors on the phosphor screen, and magnifies the phosphor screen emitted by this ultraviolet irradiation device. An optical system, a color camera that images the phosphor screen magnified by this optical system, and separates the image of the phosphor screen taken by this color camera for each color of phosphor, and calculates the light emitting position and light emission of the phosphor for each color. A phosphor screen inspection device comprising: an image processing device for comparing areas.