JPS60109392A - Detector of white color shading - Google Patents

Abstract

PURPOSE:To make it possible to evaluate quantitatively white color shading of a color cathode ray tube by image-picking up two monochrome screens which are projected sequentially through the same colored optical filter, and by comparing the picture data for both screens with each other. CONSTITUTION:A color television receiver 1 to be inspected receives a monochrome image signal from a test pattern signal generation circuit 4, and projects a monochrome screen. A monochrome picture is image-picked up by a television camera 3 through a monochrome optial fiber 2. The one-frame-period picture data, which are obtained by image-picking up one monochrome screen, are written in a frame memory 7, and the data, which are obtained by image-picking up other monochrome screens, are written in a frame memory 8. The picture data which are stored in the frame memories 7 and 8 are subtracted or divided with each other by an arithmetic circuit 10. A computer 12 evaluates the color shading based on these arithmetic results.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a white unevenness inspection device suitable for use in image quality calibration in quality control of television receivers and the like.

[Background of the invention]

Conventionally, when manufacturing a television receiver, a quality control step is provided as the final step of the manufacturing line, and the performance of the television receiver is inspected in this step.

For this performance test, methods are adopted depending on the target to be tested. One method is to project a test pattern, which is a still image, on the screen of the television receiver to be tested. There is a method of inspecting the image quality of a test pattern to evaluate the quality of the performance of the television receiver to be inspected.

By the way, in recent years, automation and labor saving have been promoted in the manufacturing process of television receivers, but in the quality control process, which is one of the processes, the image quality is
The inspection required two people.

The current situation is that public inspections are conducted based on visual evaluation of test patterns by experienced inspectors.

shi〃）shi, with this image quality inspection method based on visual evaluation, there are individual differences in evaluation, poor reproducibility of evaluation,
There are problems such as the low tolerance level of the test and the need for skill in calibration, making it extremely difficult to obtain objective test results and making it impossible to carry out sufficient quality control.

In particular, the white uniformity of color cathode ray tubes is one of the most important factors that affects the image quality of color television receivers, and among many inspection items, white unevenness inspection of color cathode ray tubes is one of the important inspection items. It has become.

One of the causes of uneven white color on a color cathode ray tube, that is, the white color is non-uniform across the entire screen, is the landing error of the electron beam, that is, the electron beam that passes through the hole in the Shisedou mask does not accurately hit the corresponding firefly. The white unevenness in conventional color cathode ray tubes is mainly due to this landing error.

Conventionally, the conventional method for inspecting such white unevenness has been a visual method, in which monochromatic screens of red, green, and blue are sequentially projected as a test pattern on a color television receiver to be inspected. White unevenness was inspected by visually evaluating the color unevenness on a monochromatic screen. However, this method has the problems mentioned above.

In response to this, a method was proposed to conduct all inspections for white unevenness by making the landing error visible (Japanese Unexamined Patent Publication No. 4
No. 9-40426]. In this method, all 15 points on the screen of the color cathode ray tube to be inspected are imaged at high magnification, each fish is sequentially imaged at high magnification using an industrial Ten Vision camera, and the magnified screen is projected. This method is used to visually measure the position of the pattern. According to such a method, it is possible to improve to some extent in terms of individual differences in evaluation and reproducibility, but
In addition, a certain amount of technical skill is required to inspect the dishes.

In addition, in recent years, blurred CRT tubes have become the mainstream color cathode ray tubes, but in addition to landing errors, irregularities in the shape and size of graphite holes are the main cause of white unevenness in such blurred and sock tubes. , the white uniformity is decreasing.

For this reason, more and more sophisticated techniques are required to inspect white unevenness, and it is necessary to inspect the entire screen without corners, taking into account irregularities in graphite holes. Therefore, in the method described in Toi JP-A No. 49-4 (] 426), it would take a very long time to inspect all the white irregularities on one color cathode ray tube, making it impractical. Almost impossible to implement.

[Purpose of the invention]

The present invention eliminates the drawbacks of the above-mentioned prior art and provides
7' A white unevenness inspection device with a simple circuit configuration that can objectively and objectively evaluate the white color uniformity of a tube in real time? ] l - It is in the capture offer.

[Summary of the invention]

In order to achieve this purpose, the present invention sequentially projects two screens for two different monochromatic image numbers on a color cathode ray tube to be inspected, and images the screens by using the same color filter. The method is characterized in that the white unevenness of the color cathode ray tube to be inspected can be easily evaluated by obtaining image data for each screen and subtracting or dividing the image data from each other. .

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a white unevenness inspection apparatus according to the present invention, in which 1 is a color television receiver to be inspected, 2 is a monochromatic filter, 3 is a television camera, and 4 is a test pattern. Signal generation circuit, 5 is the same signal generation circuit, 6 (air analog-to-digital conversion circuit, 7.8
9 is a screen switching circuit, 10 is an arithmetic circuit, 11 is a 7-frame memory, and 12 is a computer.

2 in the figure, a color television receiver 1 to be inspected is supplied with a monochrome video signal from a test pattern signal generation circuit 4 and displays a monochrome screen, and this monochrome image is passed through a monochrome optical filter 2 to The image is captured by camera 3. The television camera 6 and the test pattern signal generation circuit that generates all the monochromatic test pattern signals have the same synchronization (a synchronization signal is supplied from the N number generation circuit 5,
For this reason, the color television receiver 1 to be inspected and the television camera 3 are synchronized.

The screen switching circuit 9 operates based on instructions from the computer 12, controls the test pattern signal generating circuit 4 to switch the monochrome screen displayed on the color television receiver 1 to be tested, and also controls the frame memory 7.8. are also in a writing state.

Therefore, the image data for one frame period obtained by imaging a certain monochromatic screen displayed on the color television receiver 1 to be inspected is stored in the frame memory 7, and used to capture another monochromatic screen. The image data obtained during the 17V-frame period is written into the 7-frame memory 8.

Performance! The circuit 10 subtracts or divides the image data stored in the frame memory 7.8 from each other at each sampling point, and supplies the obtained calculation results to the frame memory 11. When the calculation results for all sampling points are written to the frame memory 11, the computer 12
All evaluations of color unevenness are performed based on the calculation results of 0remo.

Next, the operation of this embodiment will be explained.

First, let's talk about landing error, which is one of the causes of white unevenness on the projection screen of color television receivers.
This will be explained with reference to FIG.

FIG. 2 is an enlarged view showing a part of the fluorescent surface of a pravkumatorivkus type color cathode ray tube. body part G,
The blue phosphor parts B are arranged in the horizontal direction in the order of 1111 R2O, B, and between these phosphor parts R, G, B, a non-emitting part N is provided.

Therefore, when a white screen is projected on a color cathode ray tube, an electron beam modulated by a red signal (hereinafter referred to as a red electron beam) is used, or a predetermined hole provided in a shadow mask (not shown) is used to completely pass through the red beam. An electron beam (hereinafter referred to as green electron beam) irradiated onto the phosphor section H and modulated by the C green signal f'L is irradiated onto the green phosphor section G, and an electron beam modulated by the blue signal is emitted. The beam (hereinafter referred to as the "brown color beam") is irradiated to the blue phosphor section B.The red phosphor section R emits red light, and the green phosphor section G emits green light. The blue phosphor portion B emits blue light L, and the additive color mixture of these primary colors produces a white source.

In this case, the red electron beam is irradiated only on the red phosphor 111R, the green electron beam is irradiated only on the green phosphor part G, and the blue electron beam is irradiated only on the blue phosphor part B. This may be due to the uniform white part of the projection screen of the color cathode ray tube, or to the part where there is a landing error of the projection screen, where the electron beam is concentrated on the phosphor part with a constant Qr, resulting in h < s blinking fluorescein. Part of the body will be irradiated with t. That is, as shown in FIG. 2, the red electron beam is irradiated onto a range SR spanning the red phosphor section R and a part of the green phosphor section G, and the green electron beam is irradiated onto a range SR spanning the red phosphor section R and a part of the green phosphor section G. The blue electron beam is irradiated onto a range So spanning the blue phosphor part B and a part of the red phosphor part B, and the blue electron beam is irradiated onto a range SR spanning the blue phosphor part B and a part of the red phosphor part R. Ru.

As a result, the proportions of red light, green light, and blue light generated in each of the phosphor portions R1G and R1B change, resulting in white unevenness on the screen of the color cathode ray tube.

Therefore, the operation of this embodiment when white unevenness occurs due to the cause shown in FIG. 2 will be described.

2 in FIG. 1, a green filter is attached as the monochromatic optical filter 2, and under the command of the computer 12, the screen switching circuit 9 generates the green test pattern (the i sound is generated and A green screen is displayed on the pre-mortem color television receiver 1, and at the same time, the frame memory 7 is put into the empty state, and the frame memory 8
is set to non-write state.

In this case, in the part of the screen projected on the color television receiver 1 to be inspected where white unevenness does not occur, the range 3G where the fluorescent surface is irradiated with the green electron beam is irradiated with green fluorescent light, as shown in FIG. In areas where only the light body part G is overlapped or white unevenness occurs, as shown in Fig. 6+fi+ f), not only the green phosphor part G but also a part of the blue phosphor part B may be covered. become. Therefore, in this portion, the blue phosphor portion B also generates a blue source, albeit slightly, and becomes a blue-tinged green color.

Therefore, if we set the monochromatic filter 2 as a green filter and take an image of this screen with the television camera 3 through the entire green filter 2, the green filter 2 will transmit only green light and block other primary color sources. Because it is a thing,
Only the green light emitted from the green phosphor section G is received by the television camera 3. Therefore, in the parts of the color television receiver 1 to be inspected where white unevenness does not occur, the third
As shown in Fig. 1al, green light is emitted over the entire width (hatched area) of the green phosphor portion G, and the amount of emitted light L is large, but in the part where white unevenness occurs, as shown in Fig. 4 fb+. , the part excluding a part of the green phosphor part G (lateral line part)
Since green light is emitted from the source, its emission will be reduced.

By receiving such green light, a video signal for a green screen from the television camera 3 is supplied to an analog-to-digital conversion circuit (hereinafter referred to as A/D conversion circuit) 6, for example, at a suntouring point 45. It is converted into digital value image data representing the entire 256th floor view with a thread width of 0 to 255 inches. This image data is stored in frame memory 7.
17 frames of image data are written into the frame memory 7.

Next, the computer 12 sends the command icon to the screen switching circuit 9.
The screen switching circuit 9 causes the test turn signal generating circuit 4 to generate a red test pattern beep, and a red screen image is displayed on the color television receiver 1 to be tested. The memory 7 is set to a non-writing state, and the 7-frame memory 8 is set to a fully written state.

In this case, in the part of the screen projected on the color television receiver 1 to be inspected where white unevenness does not occur, the red electron beam is irradiated only to the red fluorescent body part H, as shown in FIG. Another firefly body it's G.

B does not emit light, but in the part where white unevenness occurs, the red electron beam also irradiates a part (shaded part) VC of the green phosphor part G, as shown in Figure 5, and the green light is emitted from this part. As a result, the projected screen becomes a greenish-red screen.

Therefore, when such a projected screen is imaged by the television camera 3 through the green filter 2, the green filter 2 blocks the red light and transmits only the green light. In the area where white unevenness does not occur, the red light is blocked and the amount of light received by the television camera 3 becomes zero, as shown in FIG. On the other hand, in the part where white unevenness occurs on the projection screen of the color television receiver to be inspected, the red electron beam is irradiated fL, and part of the green phosphor part G is irradiated with τ, as shown in FIG. 1t+1. Since green light is generated from the television camera 3, this green light passes through the green filter 3 and is received by the ten vision camera 3.
An image signal having an amplitude corresponding to the amount of reception e is obtained.

The image signal obtained from the television camera 3 is A/D
The image data is converted into a digital signal by the conversion circuit 6 to become image data, and one frame of the image data is stored in the 7-frame memory 8.

When 17V of image data is stored in each of the frame memories 7 and 8, next, these frame memories 7 and 8
At the same time, the sky image data is read out from the arithmetic circuit 10.
That is, this image data consists of digital values at a series of sampling points of the image signal that is sampled 11 in the A/D conversion circuit 6, and is supplied to the frame memory 7.
．． From 8 onwards, the digital values at each sampling point are read out one by one, and are stored in the frame memory 7.
The image data read out from the frame memory 8 at the same time is the digital value at the same sampling point corresponding to each other, that is, the same position on the projection screen of the color television receiver 1 to be inspected. .

The arithmetic circuit 10 subtracts or divides the supplied image data, and sends the result of this arithmetic operation to the frame memory 11V.
c supply. That is, when performing a subtraction process, all the image data supplied from the frame memory 8 is subtracted from the image data supplied from the frame memory 7, and when performing a division process, the image data from the 7some memory 7 is subtracted from the image data supplied from the frame memory 7. Divide by the image data of frame memory 8.

In all of these calculation results, the thicker the white unevenness (V'-), the smaller the value.

When the calculation results of all 17 frames of image data are written into the 7 frames memory 11, the computer 12 reads out these calculation results and performs predetermined processing to determine the degree of white unevenness.

Next, the determination of the degree of white unevenness in Example 2 will be explained.

FIG. 7 is an explanatory diagram showing an example of the light emitting state of the fluorescent surface of a color cathode ray tube when the projection screen is a green screen, and parts corresponding to those in FIG. 2 are given the same reference numerals. .

1. Regarding the part of the projected screen of the color television receiver 1 to be inspected (Figure 1) that does not have uneven white color, the brightness when the projected screen is a red screen is VRs.The brightness when the projected screen is a green screen is VRs. If Vah is the brightness when the screen is blue, and VB is the brightness when the screen is blue, then the television camera in the area where white unevenness does not occur when the projection screen is green! +(1st
The blade level VQ of the figure) is VC=kio ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・(1) However, k is a proportionality constant, and γ is a constant representing the comma characteristic of the television camera 3.

On the other hand, when the projection screen is located in a part where white unevenness occurs and the projection screen is completely white, the irradiation width of the green electron beam is changed to each phosphor portion R, G as shown in FIG. , equal to the width W of B, this green nL electron beam is irradiated from the green firefly body part G to the twinkling blue firefly body part B over a width X, the source region of the green electron beam. is the diagonally shaded area A (l) in the upper right corner, then the irradiation area of the red electron beam shifts in the same way, and the source area of the red electron beam becomes the diagonally shaded area AR in the lower right corner, extending the width X to the green phosphor part G. It will take only

Therefore, the output level V of the television camera 3 for the green light in the area where such white unevenness occurs. If the width of the non-light source part N is a, then

Tonoyo')Ic, the cutting level of the television camera 3 is completely influenced by its gamma characteristics.When γ=1, it is proportional to the large brightness, and the gradation of the input image and cutting image are equal, but , γ>1, the change in the cutting edge becomes rapid with respect to a change in the input, the gradation of the cutting edge image becomes narrower, and the contrast becomes sharper. When γ>1, the contrast becomes weaker.

By the way, in recent years, Ten Vision cameras are capable of solid-state photography of 1 second!
The element is used, and the comma characteristic & engineering γ = 1 of the solid-state image sensor
It is. Therefore, it is assumed that the television camera 6 uses a solid-state image sensor as the image sensor, and in order to simplify the calculation, the above formulas (1) and (2) are used. 2, and γ=1.

Therefore, the brightness is 1! due to the white unevenness caused by the degree x of other colors! tf conversion ΔVO (=V5-VQ)
is calculated by the following formula, giving t degrees Celsius.

X0a X Δvo= −−v o−vR・・・・・・・・・・・・
・(3) According to W W PI, if one television receiver in the test area is set to one red screen, the brightness change Δv due to white unevenness will occur.
R is as shown in the following formula.

Figure 8 1al is 2 (31, (41), Il '! of other colors!

It is clear from the graph 1, which is a graph showing the brightness changes for the different colors, that ΔVa +ΔV− and other materials and other color degrees X greatly monotonically decrease and monotonically increase.

Therefore, if the arithmetic circuit 10 (FIG. 1) calculates the difference between the green screen and the red screen, for example, by subtracting the value P of the corresponding point of the red screen data from the green screen data, white unevenness will occur. A difference in brightness of ΔV-ΔvR is obtained between the normal portion where no white unevenness occurs and the portion where white unevenness has occurred. From this difference in brightness, the degree X of the other colors can be estimated. At the same time, it is also possible to measure the extent, density, and area of the area where the white unevenness occurs.

Next, from the above equations (3) and (4), if we calculate the ratio of the brightness of the green screen and the red screen with respect to the degree of other color printing,
Figure 8 (blVC) is shown. Therefore, in the arithmetic circuit (Figure 1), one of the screen data of the green screen and the red screen is used as a divisor, for example, the red screen data is used as the divisor, and the screen data of each screen is By performing a division operation on the corresponding point by 1 (t1) in Fig. 8, the degree of coloring Xi can be determined.

In addition, the area of the area where white unevenness occurs can also be measured at the same time.

As described above, according to this embodiment, for example.

The same green optical filter is used to image the color television receiver to be inspected using a television camera, and the difference or ratio between the brightness of the green screen and the brightness of the red screen displayed on the color television receiver to be inspected is determined. By all asking, uneven white color? It can be quantified, and quantitative inspection of white unevenness becomes an ability. Furthermore, this example can be constructed using existing technology and has a simple circuit configuration, and is also based on data obtained by measurements using the same optical filter and the same television camera. Since the calculation is performed, there is no need to convert the original filter or the television camera. Therefore, there is no need for correction due to differences in the characteristics of each, and the inspection work is also simplified.

〔Effect of the invention〕

As explained above, according to the invention The objectivity is maintained, the reproducibility of the test results is the same as above, and the reliability is increased [7] The circuit configuration does not become complicated, and the white unevenness test has excellent functions except for the points of the conventional technology mentioned above. equipment can be provided.

[Brief explanation of the drawing]

Fig. 1 is a professional diagram showing one embodiment of the white unevenness inspection device according to the present invention, Fig. 2 is an enlarged front view showing a part of the base surface of a color cathode ray tube, and Fig. 6 is a green color. An enlarged front view illustrating the state of normal parts and white uneven parts of the fluorescent surface of a color cathode ray tube when used as a screen, FIG. Enlarged front view showing the original state of the color cathode ray tube as seen through a green optical filter, Figure 5 1a
l, lbl are enlarged front views showing all the light emitting conditions of the normal part and white uneven part of the fluorescent surface of the color cathode ray tube when the screen is set to red; Figure 7 is an enlarged front view showing the entire original state of a color cathode ray tube when the red screen of BL is viewed through a green optical filter. The enlarged front view of FIG. 8 is a graph showing the #iL degree with respect to the degree of white unevenness. 1. Color television receiver to be inspected. 2. Single, color redundant. science filter, 3...television camera, 4.
,. Test pattern signal generation circuit, 5... Synchronization signal generation circuit, 6... Analog-digital conversion circuit% 7, 8.
...Frame, warp, 9...Screen switching circuit, 10.
...For the Xth performance, 11...7 ram memory, 12...
Computer.・'' ＼ Representative Patent Attorney Akira Higashi Takahashi: , ,) Figure 11 Figure 4 (a) (b) Figure S (a) (b), 6. Figure 7.

Claims (1)

[Claims] By applying different first and second monochrome video signals to the color television receiver to be inspected, different first and second monochrome video signals are sequentially applied. A white unevenness inspection device designed to project the monochromatic screen of Hayabusa 2 includes a first filter that transmits monochromatic light, and a white unevenness inspection device that projects the monochromatic screen displayed on the color television receiver to be inspected. a gR device that captures an image through a nine filter;
1. storing the video signal obtained by the imaging device as image data; At least a second 7-ray I memory and an arithmetic circuit for subtracting or dividing the image data stored in the second frame memory are provided, and the first frame memory is connected to the first frame memory. The second frame memory stores the image data obtained by applying the first monochromatic video signal to the color television receiver to be inspected to display the first monochromatic screen of monochromatic light, and the second frame memory In order to display the second monochromatic screen of a second monochromatic light different from the monochromatic light of 1, the monochromatic video signal of @2 is provided to the color television receiver to be inspected. 1. A white unevenness inspection device, characterized in that it is configured to store image data and inspect white unevenness based on calculation results by the arithmetic circuit.