JP3585695B2 - Slit type shadow mask inspection equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inspection apparatus for a slit type shadow mask used for color selection of a color cathode ray tube (CRT), and more particularly to an inspection apparatus for inspecting a state of a side wall of a slit opening.
[0002]
[Prior art]
Sidows masks used for color selection of color cathode ray tubes (CRTs) initially responded to the demand for high resolution by processing the shadow masks themselves with high precision. It was recognized that the color shift due to thermal expansion due to the electron beam cannot be ignored when using color sorting incorporated in a CRT, and a low expansion invar material was used as a shadow mask material, or a shadow mask was fixed to a frame. In such a case, a slit type that uses tension on a shadow mask has been used.
The slit type shadow mask usually has a shape as shown in FIG. 7, and is manufactured by etching.
7A is an overall schematic view, and FIG. 7B is an enlarged view of a dotted circle C0 in FIG. 7A, and FIG. 7C, FIG. 7 (c) and (b) are diagrams each showing a cross section taken along line C1-C2 in FIG. 7 (b).
When the cross-sectional shape of the slit opening is as shown in FIGS. 7 (c) and 7 (a), the plate thickness is thin, so that it is penetrated by etching from only one side, and in the case of FIGS. Is performed from both sides.
Then, as shown in FIG. 8, the shadow mask 860 is fixed to a color cathode ray tube (CRT) 800 and fixed to a frame 870 to be incorporated in such a shadow mask.
The color cathode ray tube (CRT) 800 allows an electron beam 815 from an electron gun 810 scanned while being controlled in deflection by a deflection yoke 820 to pass through a slit portion of a shadow mask 860 and emit light to a fluorescent screen 850. The person in front of panel 840 sees the emission of the phosphor screen.
[0003]
As a method of fixing the slit type shadow mask to a color cathode ray tube (CRT) using a frame, a method using thermal expansion and a method using frame pressure are known.
The one using thermal expansion is called Zenith's FTM (Flat Tension Mask), and utilizes the difference in thermal expansion between a metal slit-type shadow mask and a ceramic frame having a thickness of about 25 μm, The assembly is performed at a high temperature, and at room temperature, tension is applied as the metal shrinks.
The method using the frame press uses a slit-type shadow mask (also called an aperture grill) having a thickness of about 100 μm, and is fitted to a frame having an R surface called an Oitaco through the mask. A frame that is sandwiched (chucked) on the R surface with a tension, tension is applied to the R surface by frame positioning, the frame is pressed, and the mask is welded and fixed to the pressed frame. It is.
[0004]
[Problems to be solved by the invention]
In these slit-type shadow masks, further improvement in quality and stabilization are desired, and inspection of an aggressive defect or a defective protrusion on the side wall of the slit opening as shown in FIG. It has become.
On the other hand, as a conventional shadow mask inspection technique, an inspection method using transmitted light is known as disclosed in JP-A-6-160049, JP-A-6-2229737 and JP-A-6-242014. However, it is difficult to apply these inspection methods when inspecting the side wall of the slit opening in the slit type shadow mask.
For this reason, these slit type shadow masks are used to inspect the side walls of the slit openings for egret defects as shown in FIGS. 3 (a) and 3 (b) and projection defects as shown in FIGS. 3 (a) and 3 (c). There has been a demand for an inspection device that can perform the inspection. FIGS. 3A and 3B show normal side walls.
The present invention is intended to provide an inspection apparatus for inspecting a state of a side wall portion of a slit opening of a slit type shadow mask having a slit opening penetrated by etching under such circumstances. is there.
[0005]
[Means for Solving the Problems]
The slit type shadow mask inspection apparatus of the present invention directs a slit type shadow mask used for color selection of a color cathode ray tube (CRT) having a slit opening in a direction orthogonal to a transport direction, An inspection device for inspecting a state of a side wall portion of the slit opening while being conveyed, wherein at least a slit opening side having a side wall portion has a slit facing the slit opening side via a first beam splitter. A first linear light source that irradiates light to one side wall of the first, a first line sensor that inputs specularly reflected light of light incident on the side wall portion via the first beam splitter, A second linear light source that irradiates light to the other side wall of the slit opposed thereto through the beam splitter, and a positive light beam that enters the side wall portion through the second beam splitter. A first beam splitter, a first linear light source, a first line sensor, a second beam splitter, a second linear light source, a second line The sensor is provided substantially parallel to the slit direction of the shadow mask, and has a data processing unit that performs data processing on image signals obtained from the first line sensor and the second line sensor, respectively. The quality of the side wall portion of the slit opening is determined based on the processing result of the portion.
[0006]
[Action]
The slit-type shadow mask inspection apparatus of the present invention is configured as described above to inspect the state of the side wall of the slit opening of the slit-type shadow mask having the slit opening penetrated by etching. This makes it possible to provide an inspection device that performs inspection.
Specifically, at least, on the slit opening side having one side wall portion, via the first beam splitter, a first linear light source that irradiates light to one side wall of the slit opposed thereto. A first line sensor for inputting specularly reflected light of light incident on the side wall portion via the first beam splitter, and a second side wall of a slit opposed to the first line sensor via the second beam splitter A second linear light source for irradiating light, and a second line sensor for inputting specularly reflected light of light incident on the side wall portion via the second beam splitter, the first beam A splitter, a first linear light source, a first line sensor, a second beam splitter, a second linear light source, a second line sensor are provided substantially parallel to the slit direction of the shadow mask, and First line sensor, second line It has a data processing unit that performs data processing on the image signals obtained from the sensors, and based on the processing results of the data processing unit, judges whether the state of the side wall portion of the slit opening is good or not. Have achieved.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
A slit type shadow mask inspection apparatus according to the present invention will be described with reference to FIG.
FIG. 1 is a view showing a schematic configuration of a slit type shadow mask inspection apparatus of the present invention, and FIG. 1 shows a case where a non-defective part is photographed by a line sensor. FIG. 2 is a diagram viewed from the A0 direction in FIG. 1 and is a diagram illustrating a positional relationship between the shadow mask and the line sensor. FIG. 3 is a diagram for explaining the difference between the inspection on the normal side wall portion and the inspection on the defective side wall portion. 1 and 2 indicate the transport direction.
1, 2, and 3, 100 is an inspection device, 110 is a first linear light source, 115 is a second linear light source, 120 is a first line sensor, 125 is a second line sensor, and 130 is The first beam splitter, 135 is a second beam splitter, 140 is an image data processing unit, 200 is a shadow mask, 210 is a grill, 213 and 215 are side walls, 210A is a normal side wall, 210B is a defective side wall, 220 is Is a slit opening, 220A is a side having a side wall, and 220B is a side facing 220A.
An inspection apparatus according to the present invention is directed to a slit type shadow mask used for color selection of a color cathode ray tube (CRT) having a slit opening penetrated by etching, and the slit opening is directed in a direction orthogonal to a transport direction. This is an inspection device for inspecting the state of the side wall portion of the slit opening while being conveyed. As shown in FIG. 1, at least the first beam splitter 130 is provided on the slit opening side 220A having one side wall portion. The first linear light source 110 that irradiates the light to the side wall 213 opposed thereto and the second linear light source 110 that inputs the specularly reflected light of the light incident on the side wall 210 via the first beam splitter 130 A second linear light source 115 for irradiating light to a side wall 215 opposed thereto via one line sensor 120, a second beam splitter 135, and a second beam splitter; Of light incident on the side wall portion 215 through 135, and a second line sensor 125 for inputting the regular reflection light.
The first line sensor 120 and the second line sensor 125 in the apparatus shown in FIG. 1 are built into a camera, and are CCD elements or the like.
[0008]
As shown in FIG. 2, the first line sensor 120 and the second line sensor 125 are provided along the direction of the grill 210 of the shadow mask 200, that is, along the direction of the slit opening, and are provided substantially parallel thereto. .
Of course, although not shown in FIG. 2, the first linear light source 110, the first beam splitter 130, the second linear light source 115, and the second beam splitter 135 are also provided in the slit openings 220 of the shadow mask 200. And substantially parallel to it.
[0009]
As shown in FIGS. 3B and 3A, in the normal side wall 210A shown in FIGS. 3A and 3B, the incident light is reflected by the defective side wall 210B shown in FIGS. 3B and 2B. 3B, the ratio of the amount of light regularly reflected in the incident direction is much larger than that of the defective side wall portion 210B shown in FIGS. For this reason, when there is the defective side wall portion 210B shown in FIG. 3B and FIG. 3B and the ratio of the regular reflection light amount becomes extremely small due to the irregular reflection, the detection signal focusing on one pixel of the line sensor is shown in FIG. (B).
On the other hand, when there is no defective side wall portion, a detection signal focusing on one pixel of the line sensor is as shown in FIG.
Focusing on one line of the line sensor, if there is a defective side wall portion 210B shown in FIG. 3B and FIG. 3B and the ratio of the amount of regular reflection light becomes extremely small due to irregular reflection, the detection signal will be as shown in FIG. As shown in FIG. 5B, when there is no defective side wall portion, the detection signal is as shown in FIG.
Therefore, different detection signals are obtained with and without the defective side wall portion 210B shown in FIGS.
In brief, the quality of the signal can be determined based on the signal level of the obtained signal, and the presence or absence of the defective side wall portion can be known from the quality of the signal.
[0010]
As described above, the presence / absence of a defective side wall portion can be known from the obtained signal because the detection signal level is different depending on whether or not there is a defective side wall portion. The data processing will be specifically described with reference to an example of 140.
Note that S61 to S64 indicate each step of the processing.
The data processing unit shown in FIG. 6 simply associates image data from the line sensor in the image data memory with each pixel position of the line sensor and the number of scans, and scans a predetermined number of scans. For each data at each position in the image memory, the data is compared with a predetermined slice level, and based on the result, the quality of the state at the position of the shadow mask corresponding to each position in the image memory is determined. is there.
Although not described in detail here, if the image data is integrated for each pixel while being shifted at a fixed interval, or if a moving average is taken, the image data is less likely to be affected by noise or positional deviation.
In FIG. 6, 610 and 610A are pixel data, 620 is an image data memory, 630 and 635 are gates, 640 is a decision unit, 650 is a switching unit, 660 is a good (OK) signal output, 670 is a bad signal output, and 680 is a bad signal output. A control unit, 690 is a counter, and 695 is a comparison unit.
First, image signal data (image data 610) obtained from the first line sensor 120, the second line sensor 125, and the like are loaded into the image memory 620 for a predetermined number of scans (number of lines). (S61)
Each position of the image memory 620 corresponds to each position of the shadow mask.
Next, for the captured image data 610A, for each pixel, the image signal level is compared with a predetermined slice level signal to determine whether there is a defective portion in the corresponding shadow mask detection unit. . (S62)
Next, for each pixel of the image data memory, if it is determined that the pixel is defective, a corresponding defective signal is sent to the control unit 680 via the switching unit 650. If it is not determined that the pixel is defective, the switching unit is used. A good (OK) signal is sent to the control unit 680 via 650. (S63)
The control unit 680 sends the obtained information to a line management device (not shown). (S64)
[0011]
The gate 630 sends the contents of the image data memory 620 to the determination unit 640 to determine whether or not to perform the determination processing, and is controlled by conditions such as a transport system for transporting the shadow mask.
In the case of the example shown in FIG. 6, a signal for detecting the feed amount for transporting the shadow mask is confirmed by the counter 690, and the data obtained by the counter 690, and other inspection start conditions (signals), inspection end conditions ( Signal).
When a failure occurs, the gate 635 opens the gate 635 in accordance with the failure signal, and sends the shadow mask feed amount from the counter 690 to the control unit. As a result, information on the location where the defect has occurred is transmitted to the line management device via the control unit. Then, if necessary, after distributing the shadow mask alone, only the shadow mask designated as defective is removed.
Although not described here, when combined with the data in the width direction of the line sensor, it becomes information indicating the exact position of the defect.
[0012]
【The invention's effect】
As described above, the present invention makes it possible to provide an inspection apparatus for inspecting a state of a side wall portion of a slit opening of a slit type shadow mask having a slit opening penetrated by etching.
As a result, further improvement and stabilization of quality can be expected in such a slit type shadow mask.
[Brief description of the drawings]
1 is a schematic configuration diagram of a slit-type shadow mask inspection apparatus according to the present invention; FIG. 2 is a diagram showing a positional relationship between a shadow mask and a line sensor; FIG. 3A is a side wall defect; FIG. 3B is a diagram for explaining a difference in reflected light between a normal side wall portion and a defective side wall portion. FIG. 4 is a detection signal diagram. FIG. 5 is a detection signal diagram. FIG. 7 is a diagram for explaining data processing. FIG. 7 is a diagram for explaining a slit type shadow mask. FIG. 8 is a diagram for explaining a color cathode ray tube (CRT).
Reference Signs List 100 inspection apparatus 110 first linear light source 115 second linear light source 120 first line sensor 125 second line sensor 130 first beam splitter 135 second beam splitter 140 image data processing unit 200 shadow mask 200A Shadow mask material 210 Grill 213, 215 Side wall 210A Normal side wall 210B Bad side wall 220 Slit opening 220A Side 220B having (one) side wall 220B Side opposite to 220A 610, 610A Pixel data 620 Image data memory 630, 635 Gate 640 Judgment section 650 Switching section 660 Good (OK) signal output 670 Bad signal output 680 Control section 690 Counter 695 Comparison section 700 Shadow mask 710 Grill 715 Slit 720 Peripheral section 722 Notch 730 Opening area 800 Color -Cathode ray tube (CRT)
810 electron gun 815 electron beam 820 deflection yoke 830 funnel 840 panel 850 phosphor screen 860 shadow mask 870 frame

Claims (1)

A slit type shadow mask used for color selection of a color cathode ray tube (CRT) having a slit opening is provided with the slit opening directed in a direction perpendicular to the conveying direction, and the side wall portion of the slit opening is conveyed. An inspection apparatus for inspecting, at least, on the slit opening side having one side wall portion, through the first beam splitter, irradiate light to one side wall of the slit facing the first side A linear light source, a first line sensor for inputting specularly reflected light of light incident on the side wall portion via the first beam splitter, and a slit of the slit opposed thereto through the second beam splitter. A second linear light source that irradiates light to the other side wall, and a second line sensor that inputs specularly reflected light of light incident on the side wall portion via the second beam splitter, First bi A splitter, a first linear light source, a first line sensor, a second beam splitter, a second linear light source, a second line sensor are provided substantially parallel to the slit direction of the shadow mask, and , A data processing unit that performs data processing on image signals obtained from the first line sensor and the second line sensor, and based on the processing result of the data processing unit, whether the state of the side wall of the slit opening is good or bad. An inspection apparatus for a slit type shadow mask, characterized in that the inspection is performed.

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