JPH0831324A - Method and device for inspection of shadow mask - Google Patents

Abstract

PURPOSE:To inspect unevenness of a shadow mask easily by producing an electric signal complying with the light quantity passing through holes provided in a measuring region on a shadow mask, and determining the change in the light transmittance while the measuring region is shifted. CONSTITUTION:Among incident beams which are emitted from a light source 1 and put incident to a shadow mask 4, the light 6 which has penetrated holes 8 provided in a great number in the measuring region 10 is received by a light receiving means 2. The distribution of the transmittance over the shadow mask 4 is measured while it is moved by a moving means 7 in the direction of Arrow 9. In a small region containing a plurality of holes 8, the change in the mean brightness of the holes 8 and other parts is compared by a calculating means 3 with the change in the brightness resulting from unevenness of the shadow mask 4. Unevenness can be sensed by enlarging the latter brightness change resulting from unevenness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus and an inspection method for defects, which are so-called uneven defects, among defects in a shadow mask of a cathode ray tube.

[0002]

2. Description of the Related Art FIG. 11 shows, for example, Japanese Patent Laid-Open No. 63-15970.
It is a schematic block diagram which shows the conventional shadow mask inspection apparatus shown by Unexamined-Japanese-Patent No. 1-in the figure, 11 is an inspection stage and has the translucent part 13 in which the shadow mask 12 is mounted. Reference numeral 14 is a light source installed on one side of the transparent portion 13, and 16 is a camera installed on the other side of the transparent portion 13 via a shadow mask 12 placed on the transparent portion 13. Is located at a position facing the light source 14. An image measuring device 17 has an image memory for storing the video signal from the camera 16 as a binary signal and a microcomputer.

A screen display 18 for a monitor reads out a video signal stored in an image memory and displays it on a screen 19. FIG. 12 is a diagram showing a surface image of the shadow mask 12 which is picked up by the camera 16 and displayed on the screen 19. In the figure, 12a indicates a slit hole portion formed on the shadow mask 12, and 19a indicates a measurement region. It is the cursor line shown. FIG. 13 is an enlarged view of the slit hole portion 12a. In the figure, D is the width of the slit hole portion 12a, L is the length of the rectangular portion, and r is the radius of the semicircular portions on both sides of the rectangular portion.

Next, the operation will be described. The image of the slit hole portion 12a of the shadow mask 12 is picked up by the camera 16 and converted into a video signal, and the image measuring device 17 takes it into the image memory as a binary signal. Then, the data stored in the image memory is displayed on the screen 19 and the cursor line 19a is displayed.
The slit width D is calculated from the area and the number of the slit holes 12a in the measurement area set by
The so-called uneven defect caused by the nonuniformity of the slit area or the width on the shadow mask is inspected.

[0005]

Since the conventional shadow mask inspection apparatus is constructed as described above, the image of the slit hole portion 12a of the shadow mask 12 is stored in the image memory as a binary image. It is necessary to capture a high-definition image and perform arithmetic processing for each of the slit holes 12a provided in a large number on the measurement range on 12, and the apparatus becomes expensive, and it takes a lot of time for inspection. was there.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to individually measure the slit holes of the shadow mask by utilizing the property of the uneven defect from the viewpoint of visibility. An object of the present invention is to provide a shadow mask inspection apparatus and inspection method that can easily inspect for uneven defects from changes in the average transmittance of a plurality of slit holes of a shadow mask without need.

[0007]

A shadow mask inspection apparatus according to the present invention comprises a light source arranged on one side of a shadow mask, and a measurement set on the other side of the shadow mask. Movement that moves the measurement area by changing the relative position of the light receiving means that receives the passing light from the light source that passes through the hole in the area and generates an electric signal corresponding to the received light amount, and the shadow mask and the light receiving means And means for obtaining a change in the electric signal from the light receiving means associated with the movement of the measurement area, and for calculating and outputting the distribution of the transmittance within the measurement area.

Further, from a light source arranged on one side of the shadow mask and a light source arranged on the other side of the shadow mask and passing through a hole in an image area including a measurement area set on the shadow mask, Light receiving means for receiving the light passing therethrough and generating a video signal corresponding to the brightness distribution thereof, moving means for moving the video area by changing the relative position of the shadow mask and the light receiving means, and changing with the movement of the video area. And a calculation means for calculating and outputting the distribution of the transmittance within the measurement region from the image obtained by the image signal.

Further, it is provided with a detecting means for detecting a defect of the shadow mask based on the calculation result from the calculating means. Further, the optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicularly, the measurement region includes the optical path in the region, and the moving direction by the moving means is parallel to the shadow mask, and the calculating means is The configuration is such that the transmittance distribution along the moving direction is calculated. Further, the light receiving means is a spot type luminance meter, and the spot type luminance meter is arranged so that a plurality of holes are included in the measurement area.

Further, the light-receiving means is a light-shielding tube type luminance meter, and the light-shielding tube type luminance meter is arranged so that a plurality of holes are included in the measurement area. Further, the light source is used as a light source that emits condensed light, and the light source and the shadow mask are such that the spot formed on the shadow mask by the irradiation light from the light source has a spot size including a plurality of holes of the shadow mask. Is arranged. Further, the light source is a diffused light source that emits light diffused in the direction normal to the light emitting surface.

Further, the optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicularly, and the moving direction of the measurement region by the moving means includes the optical path and is substantially perpendicular to the optical path, and the light source and the light receiving The means are arranged so as to face each other in a line shape in a direction substantially perpendicular to the optical path direction and the moving direction. Further, the shadow mask inspection method according to the present invention obtains, as the transmittance, the degree of light passing through the hole in the measurement area set on the shadow mask, and moves the measurement area to move the transmittance in the area. Is calculated to calculate the unevenness defect of the shadow mask.

[0012]

The shadow mask inspection apparatus according to the present invention is
The light receiving means receives the passing light from the light source passing through the hole existing in the measurement area set on the shadow mask to generate an electric signal, and the moving means moves the measurement area, and the calculating means measures. An averaged luminance distribution is calculated and output from the change in the transmittance with the movement of the area.

Further, the light receiving means receives the passing light from the light source which passes through the hole existing in the measurement area set on the shadow mask, and generates a video signal corresponding to the brightness distribution. Then, the measuring means is moved by the moving means, and from the change in the image area due to this movement, the calculating means calculates and outputs the averaged luminance distribution of the transmittance in the corresponding changing measuring area. Further, the detection means detects the unevenness defect from the calculation result.

Further, the optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicular to each other, and the measurement area includes an optical path within the area, and the moving direction of the moving means is substantially perpendicular to the optical path direction. As a result, the amount of light emitted from the light source irradiating the measurement area is maintained at a constant intensity, and the transmittance of the transmitted light changes while the amount of light from the light source is kept constant along the moving direction by the computing means. Is calculated.

Further, the light transmitted from the light source through the shadow mask is projected as a measurement area portion onto the light receiving portion in a spot manner, and the light receiving portion depends on a plurality of holes in the measurement area and other than the holes. It receives incoming transmitted light. It also receives the transmitted light that passes through the inside of the measurement area on the shadow mask that is regulated by the light-shielding cylinder as viewed from the light receiving element. Further, by irradiating the shadow mask with the condensed light, the light is spotwise incident on the measurement region on the shadow mask.

Further, a diffused light source that emits light in the direction normal to the light emitting surface is used as a light source having a non-directional and uniform luminance distribution. Further, the optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicularly, and the moving direction of the measurement region by the moving means includes the optical path and is substantially perpendicular to the optical path, and the light source and the light receiving means are the optical path. It is arranged in a line in a direction substantially perpendicular to the direction and the moving direction.

Further, in the shadow mask inspection method according to the present invention, the degree of light passing through the hole in the measurement area set on the shadow mask is obtained as the transmittance, and the measurement area is moved to move the inside of the area. The unevenness defect of the shadow mask is inspected by calculating the distribution of the transmittance of the.

[0018]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram schematically showing a characteristic configuration of a shadow mask inspection apparatus according to the present invention.
Reference numeral 1 denotes a light source, 2 has a light receiving surface at a position facing the light emitting surface of the light source 1, light receiving means for generating an electric signal according to the amount of received light, and 3 receives an electric signal from the light receiving means 2 and receives an electric signal. Is a calculation means for calculating the distribution of the transmittance, and in the case of the present embodiment, it includes a detection means for calculating the transmittance to detect uneven defects.

Reference numeral 4 is a shadow mask arranged between the light source 1 and the light receiving means 2 so that its surface is perpendicular to the optical path direction from the light source 1 to the light receiving means 2, and 5 is irradiated from the light source 1 to the shadow mask 4. Incident light. 6 is a transmitted light of the incident light 5 that has passed through the shadow mask 4, and 7 is a moving means for moving the shadow mask in the plane direction thereof, that is, in the direction 9 perpendicular to the optical path.

FIG. 2 is a state diagram showing the state of the surface of the shadow mask 4. In the figure, 8 is an opening hole which is a hole formed in the shadow mask.
The incident light 5 that has passed through becomes the transmitted light 6 and is received by the light receiving means 2. As described above, the shadow mask of the color cathode ray tube has a large number of apertures, and the electron beam from the electron gun expressing the three primary color components of the image, red, green, and blue, is applied to the phosphor of the corresponding apertures. The light is distributed and emitted so that it can be accurately incident. Reference numeral 10 is a measurement region, which is a light receiving range of the light receiving means 2.

Next, the operation will be described. Of the incident light 5 emitted from the light source 1 and incident on the shadow mask 4,
The light that has reached a large number of apertures 8 formed on the shadow mask 4 passes through the apertures 8 as it is and the shadow mask 4
While passing through to the opposite side to become the transmitted light 6, the incident light 5 that has reached other than the aperture 8 cannot pass through the shadow mask 4. That is, the transmitted light 6 from the shadow mask 4 is the incident light 5
Is sampled in the opening hole 8. There are several types of defects in the shadow mask, but the transmittance of the shadow mask is not uniform due to the size of the aperture in the shadow mask and the non-uniformity of the surface condition inside and inside the aperture. caused by.

Regarding the unevenness defect, as a result of examination of the visibility of the brightness change caused by the unevenness defect, it can be easily visually recognized at a position 2 to 3 m away from the surface of the shadow mask, and it becomes visible as the distance becomes shorter. Since the brightness contrast of the unevenness, which is the reciprocal of the contrast sensitivity, is very small, the spatial frequency of the brightness variation of the unevenness is the spatial frequency of the row of apertures of the shadow mask (passes through the shadow mask that changes depending on the row of apertures). It has been found that the distribution of the transmittance of the light is sufficiently larger than that of the curve when the pitch between the opening holes is used as the wavelength.

The inspection method in the shadow mask inspection apparatus of the present invention utilizes the low-frequency transmission characteristics of the spatial frequency of the light source or the light receiving means because of such characteristics of the uneven defect, and the luminance change caused by the uneven defect is particularly It is to realize the simplification of the inspection device by detecting the presence or absence of the unevenness defect from the change state of the average luminance in the measurement region by utilizing the remarkable appearance.

In FIG. 1, the transmittance distribution of the shadow mask 4 is measured while the shadow mask 4 is moved in the moving direction 9 by the moving means 7. At that time, in the area where the opening holes 8 are sampled at one time, that is, in the small area including the plurality of opening holes 8 of the shadow mask 4 of FIG. 2, averaging of the opening holes 8 of the shadow mask 4 and other portions is performed. The unevenness defect can be detected by comparing the change in the average brightness and the change in the brightness caused by the uneven defect of the shadow mask 4 and increasing the latter change in the brightness caused by the uneven defect.

FIG. 3 shows an example of the measurement result of the luminance distribution as the transmittance distribution by the inspection apparatus of the present invention, and FIG. 3A shows an example of the case of a shadow mask in which uneven defects are visually recognized.
(B) is an example in which the uneven defect is not visually recognized. In the figure, the horizontal axis is the spatial distance on the shadow mask, where the center is 0 in the horizontal direction of the shadow mask 4 and the negative memory is set to the left and the positive memory is set to the right for convenience. Yes, it is the relative movement distance of the measurement area on the shadow mask. The vertical axis is the relative brightness value.

Looking at the uneven defect visually recognizable portion in (a), the unevenness defect has a brightness change of about 2% of the average brightness, and the brightness changes abruptly. The detection means detects this portion. The spatial distance on the shadow mask where the brightness change occurs (that is, the relative movement width of the measurement area on the shadow mask) is 20 to 30 mm, and the brightness change is almost the visual limit at the observation distance of 2 to 3 m as described above. Conceivable. On the other hand, as for the result of the luminance distribution in which the uneven defect is not visually recognized in (b), the luminance is largely changed, but the pitch of the luminance change is long, and the spatial distance on the shadow mask is short as in the case of (a). It can be seen that the brightness does not change rapidly.

The calculating means detects a portion where the luminance change is abrupt from the distribution of the transmittance as in the case of (a), and judges that this portion has an uneven defect. Then, the defective portion can be easily found by inspecting the opening hole within this measurement range. In this way, in comparison with the conventional case of inspecting individual aperture holes, when the change in the light transmittance on the shadow mask is inspected as described above, when the entire shadow mask is observed like streak unevenness, When it is related to the brightness contrast, it is more effective because the uneven defect can be inspected in balance with the whole.

According to the above-mentioned structure, a place where the brightness change is abruptly detected from the distribution of the transmittance, so that it can be easily found from the change without inspecting each opening hole, and the working efficiency is greatly increased. Improve. Further, by moving the shadow mask, compared to the case of moving the light source and the light receiving means,
The moving means does not need to be rigidly configured so that the optical axes of the light source and the light receiving means are always located on a substantially straight line, and the moving means can be inexpensively constructed. When the shadow mask 4 is moved by the moving means 7 in the direction of 9 to a predetermined position such as an end portion thereof, the moving means 7 moves the shadow mask 4 in the plane in a direction perpendicular to 9 by a width corresponding to one measurement range. The inspection is carried out by moving it in the direction 9 as described above.

Example 2. Next, another embodiment will be described. FIG. 4 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention.
Constituent elements similar to or corresponding to those of the first embodiment are designated by the same reference numerals and the description thereof is omitted. 27 is a light source 1 and a light receiving means 2
The shadow mask 4 in the direction perpendicular to the optical path direction and integrally.
It is a moving means that moves in the direction 9 along the plane. Also,
Unlike the case of the first embodiment, the shadow mask 4 does not move.

Next, the operation will be described. The operation in which the light receiving means 2 receives the transmitted light 6 of the incident light 5 from the light source 1 that has passed through the aperture 8 and the calculation is performed by the calculation means 3 is the same as in the first embodiment. In this embodiment, in order to move the measurement range 10 of FIG. 2 in order to obtain the distribution of the transmittance, the moving means 27 makes the light source 1 and the light receiving means 2 perpendicular to the optical path direction, and there is a measurement area of the shadow mask 4. Move in a direction 9 parallel to the plane. At that time, the relative positional relationship between the optical path 1 and the light receiving means 2 is kept constant, and the shadow mask 4 interposed therebetween is kept.
Move against.

With such a structure, when the shadow mask is moved, the shadow mask as an object to be measured needs to be attached to the moving means alone, whereas when the light source and the light receiving means are moved. Even when the shadow mask is combined with other parts and cannot be easily moved for measurement, measurement can be performed by moving the light source and the light receiving means while arranging their optical axes on a substantially straight line.

Example 3. Next, another embodiment will be described. FIG. 5 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention.
Constituent elements similar to or corresponding to those of the first embodiment are designated by the same reference numerals and the description thereof is omitted. Reference numeral 2 denotes a light receiving means composed of a spot-type luminance meter. A convex lens 2a is provided at the entrance of the optical path, and a light receiving element 2d having an aperture 2c on a projection surface 2b is provided at the back of the optical path. 6 is the transmitted light that has passed through the aperture 8 of the shadow mask 4, 6a
Is a convergent light that is converged when the transmitted light 6 passes through the convex lens 2a and is irradiated onto the projection surface 2b.

Next, the operation will be described. In the case of a spot-type luminance meter, an image of the shadow mask 4 as a surface to be measured is projected on a projection surface 2b provided inside the luminance meter, and an aperture 2c provided on the projection surface 2b causes an aperture hole of the shadow mask 4 to be projected. Light from a small region 10 including a plurality of 8 is made incident on the light receiving element 2d, and this region is measured as a measurement region 10. Other operations are the same as those in the first embodiment.

According to the above arrangement, the image of the shadow mask is projected on the projection surface 2b with a clear contour. As a result, a small area 10 including a plurality of aperture holes 8 of the shadow mask means an area where this image is sampled from the aperture 2c, and a clear image of the shadow mask is projected on the projection surface, so that it is sampled. The range can be clearly defined, and precise measurement becomes possible.

Example 4. Next, another embodiment will be described. FIG. 6 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention.
Constituent elements similar to or corresponding to those of the first embodiment are designated by the same reference numerals and the description thereof is omitted. Reference numeral 2 is a light-receiving means composed of a light-shielding tube type luminance meter, and a light-receiving element 2e is provided in the inner part of the optical path. Next, the operation will be described. When a light-shielding tube type luminance meter is used, the light-receiving element 2e receives light from a small area 10 including a plurality of apertures 8 in the shadow mask 4 in which the light-shielding tube defines the incident range of the transmitted light 6 when viewed from the light-receiving element 2e.
The light e is received, and the brightness is measured using the small area 10 as a measurement area.

According to the above structure, since the light receiving element 2e has a size, the position of the incident small region 10 is different for each part on the light receiving element 2e. That is, the position of the small region 10 to be sampled is greatly different between the portion A and the portion B of the light receiving element 2e in FIG. Therefore, the shadow mask image, which is the object to be measured, does not become clear as viewed from the light receiving element 2e, and the measurement cannot be performed with high accuracy as when using the spot-type luminance meter, but the measurement region on the shadow mask is unclear to some extent. Since it is sampled with a different contour, the brightness due to the transmitted light in the measurement area is averaged.

Example 5. Next, another embodiment will be described. FIG. 7 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention.
Constituent elements similar to or corresponding to those of the first embodiment are designated by the same reference numerals and the description thereof is omitted. Reference numeral 1a denotes a light source of a condensing optical system using a lens system 1b, which has a structure in which diffused light from the lamp 1c is converted into parallel light by the lens 1b and is applied to the shadow mask 4. Further, the light receiving element 2 is connected to the calculating means as in the first embodiment.

Next, the operation will be described. The diffused light from the lamp 1c becomes parallel light by the lens 1b and becomes the input light 5 with which the shadow mask 4 is irradiated. The spot of the light irradiated and formed on the shadow mask 4 has a spot diameter that includes a plurality of opening holes 8 of the shadow mask 4. By irradiating the parallel light in this way, the light-receiving range of the light-receiving means 2 to be received by the light-receiving means 2 using the luminance meter as in the third or fourth embodiment becomes a measurement area including a plurality of apertures 8. Even without such limitation, it is possible to expect the same accuracy as the measurement accuracy using the luminance meter.

According to the above configuration, when a lens system is used as the light source and the light from this light source is made incident on the shadow mask 4, a spot of the incident light 5 is formed on the shadow mask 4, and the shadow mask 4 is formed. To reach the light receiving means 2 as transmitted light 6. On the other hand, light does not reach the light receiving means 2 from any place other than the spot on the shadow mask 4,
Even if the range on the shadow mask 4 that receives light on the side of the light receiving means 2 is not limited, only light from the range in which the spot is formed arrives. Therefore, a small area 10 on the shadow mask 4 is sharply outlined using a luminance meter. The same effect can be obtained by sampling with.

Example 6. Next, another embodiment will be described. FIG. 8 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention.
Constituent elements similar to or corresponding to those of the first embodiment are designated by the same reference numerals and the description thereof is omitted. Reference numeral 1d denotes a diffuser plate provided on the light source 1, which diffuses the light from the lamp 1c and irradiates the shadow mask 4 with the diffused light.

Next, the operation will be described. The light emitted from the lamp 1c enters the diffusion plate 1d, and the diffusion plate 1d
Due to the light diffusion of, the brightness of the surface of the diffuser plate is almost the same whether it is observed from the normal direction of the diffuser plate 1d or from the direction deviated from the normal line. The light source 1 having a substantially uniform luminance distribution can be obtained. When such a light source is used, the light from the light source 1 is incident on the entire surface of the shadow mask 4, and the luminance distribution of the transmitted light of the shadow mask 4 on the surface of the shadow mask 4 intersects the shadow mask 4 with the normal of the diffuser plate. The distribution has the highest value at the position, and the luminance decreases as the distance from the position increases.

By using a spot type luminance meter or a light shielding tube type luminance meter as the light receiving means, it is possible to measure the luminance of a measurement region including a plurality of aperture holes 8 of the shadow mask 4. According to the above configuration, since the light emitted from the diffuser plate has no directivity, the optical axis of the light source 1 (in this embodiment, the normal line of the diffuser plate) and the optical axis of the light receiving means are positioned on a substantially straight line. The effect that it is not necessary to perform the precise alignment and the inspection can be performed with high precision can be obtained.

Example 7. Next, another embodiment will be described. FIG. 9 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention.
Reference numeral 22 is a line sensor formed by arranging a plurality of light receiving means 2 in a line, and 1 is a light source provided so as to face each light receiving means of the line sensor 22, and in the present embodiment, is constituted by one light source. However, a plurality of light sources corresponding to the respective light receiving elements 2 may be arranged in a line so as to face the line sensor 22. Numeral 3 is an arithmetic means for obtaining an electric signal from each light receiving means 2 and detecting unevenness defects by observing the distribution of transmittance for each light receiving means.

Next, the operation will be described. Light transmitted from the light source 1 to the shadow mask 4 and passing through the aperture 8 is received by the light receiving means 2 to generate an electric signal, and the arithmetic means obtains the distribution of the transmittance based on the electric signal. The detection operation is the same as in the first embodiment. A feature of this embodiment is that the light receiving means 2 are arranged on a line so that the surface of the shadow mask 4 can be inspected only by moving the line sensor 22 in the direction perpendicular to the paper surface of FIG. Therefore, the inspection can be performed smoothly in a short time.

Example 8. Next, another embodiment will be described. FIG. 10 is a schematic diagram schematically showing the characteristic configuration of the shadow mask inspection apparatus according to the present invention. In the figure, the same or corresponding components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 2e is a camera that generates a video signal as a light receiving means, and 3a is a calculation means for obtaining the transmittance distribution of the shadow mask from the video signal of the shadow mask 4 photographed by the camera 2e. In addition, it includes a detecting means for detecting the uneven defect from the calculation of the transmittance distribution.

Next, the operation will be described. The operation until the light emitted from the light source 1 passes through the opening 8 of the shadow mask 4 is the same as that in the first embodiment. The transmitted light 6 is the camera 2
The light is received as a video signal when the surface of the shadow mask 4 is imaged by e. The calculating means 3a obtains the luminance distribution from the video signal, and the moving means 7 further moves the shadow mask 4
To obtain a distribution of transmittance, compare changes in average luminance due to uneven defects of the shadow mask 4,
The uneven defect is inspected based on the magnitude of the change.

With such a configuration, in contrast to the case where the total amount of received light received by the light receiving means is used as the transmittance as in the first embodiment, the image of the video signal corresponding to the luminance distribution as in the above configuration is used. When obtaining the transmittance, the dimensions of the measurement area including a plurality of aperture holes of the shadow mask 4 are set as a measurement area using a set of a plurality of pixels of the video signal (for example, 2 × 2 pixels, 3 × 3 pixels, etc.). Since it is possible to calculate the distribution of, the uneven defect inspection can be performed by changing the size of the measurement region variously even when the approximate uneven defect size is unknown.

In each of the above-described embodiments, the case where the shape of the opening hole 8 of the shadow mask 4 is a round hole is described as an example. However, a slit hole having a long hole shape or an aperture provided with slits in the entire vertical length of the screen of the cathode ray tube. The shape of the grill can be inspected in the same way.

[0049]

As described above, according to the present invention, the light source arranged on one side of the shadow mask and the measurement area set on the other side of the shadow mask within the measurement area are set. Light receiving means for receiving the passing light from the light source passing through the hole and generating an electric signal corresponding to the received light amount, and moving means for changing the relative position of the shadow mask and the light receiving means to move the measurement region, Since the change of the electric signal from the light receiving means due to the movement of the measurement area is obtained and the operation means for calculating and outputting the distribution of the transmittance in the measurement area is provided, it is not necessary to inspect each opening hole individually. In addition, the inspection can be easily performed from the change of the transmittance, and the working efficiency can be dramatically improved.

In addition, from a light source arranged on one side of the shadow mask and a light source arranged on the other side of the shadow mask and passing through a hole in an image area including a measurement area set on the shadow mask, Light receiving means for receiving the light passing therethrough and generating a video signal corresponding to the brightness distribution thereof, moving means for moving the video area by changing the relative position of the shadow mask and the light receiving means, and changing with the movement of the video area. Since the calculation means for calculating and outputting the distribution of the transmittance in the measurement area from the image by the video signal is provided, the transmittance distribution can be calculated by using a set of a plurality of pixels of the video signal as the measurement area, which causes a rough unevenness defect. Even if the dimension of is unknown, it is possible to obtain the effect that it becomes possible to inspect uneven defects by changing the dimension of the measurement region.

Further, since the detecting means for detecting the defect of the shadow mask based on the calculation result from the calculating means is provided,
The uneven defect can be automatically detected based on the calculation result, and the effect of further reducing the inspection load can be obtained.

Further, the optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicular to each other, and the measurement area includes the optical path in the area and the moving direction by the moving means is parallel to the shadow mask, Since the calculating means is configured to calculate the distribution of the transmittance along this moving direction, the light intensity of the light emitted from the light source becomes constant, and the effect of facilitating the calculation of the change in the transmitted light amount can be obtained.

Further, the light receiving means is a spot type luminance meter,
Since the spot-type luminance meter is arranged so that multiple holes are included in the measurement area, the image of the shadow mask with a clear outline is projected on the projection surface, so that the sample range can be clearly defined, The effect that various measurements are possible is obtained. Further, the light-receiving means is a light-shielding tube-type luminance meter, and the light-shielding tube-type luminance meter is arranged so that a plurality of holes are included in the measurement area, which has the effect of improving the accuracy of the transmittance distribution calculation. To be

Further, the light source is used as a light source that emits condensed light, and the spot formed on the shadow mask by the irradiation light from the light source has a spot size including a plurality of holes of the shadow mask. Since the shadow mask is arranged, it is possible to sample the measurement region on the shadow mask with a clear contour. Further, since the light source is a diffused light source that emits light diffused in the direction normal to the light emitting surface, the emitted light is omnidirectional, and the optical axis of the light source and the optical axis of the light receiving means are on a substantially straight line. It is possible to obtain an effect that it is not necessary to precisely perform the positioning for positioning.

Further, the optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicularly, and the moving direction of the measurement region by the moving means includes the optical path and is substantially perpendicular to the optical path, and the light source and the light receiving Since the means are arranged so as to face each other in a line shape in a direction substantially perpendicular to the optical path direction and the moving direction, there is an effect that the inspection can be smoothly performed in a short time.

Further, the degree of light passing through the hole in the measurement area set on the shadow mask is obtained as the transmittance, and the measurement area is moved to calculate the distribution of the transmittance in the area. According to the shadow mask inspection method for inspecting the uneven defect of the shadow mask, the uneven defect can be easily detected from the change of the transmittance, and the working efficiency can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a shadow mask inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial surface view showing an opening hole of a shadow mask.

FIG. 3 is a graph showing a change in luminance distribution measured by the shadow mask inspection apparatus according to the present invention.

FIG. 4 is a schematic diagram showing a shadow mask inspection device according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram showing a light receiving means of a shadow mask inspection apparatus according to a third embodiment of the present invention.

FIG. 6 is a schematic diagram showing a light receiving means of a shadow mask inspection apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a schematic diagram showing a light source of a shadow mask inspection apparatus according to a fifth embodiment of the present invention.

FIG. 8 is a schematic diagram showing a light source of a shadow mask inspection apparatus according to a sixth embodiment of the present invention.

FIG. 9 is a schematic diagram showing a shadow mask inspection apparatus according to a seventh embodiment of the present invention.

FIG. 10 is a schematic diagram showing a shadow mask inspection apparatus according to an eighth embodiment of the present invention.

FIG. 11 is a system configuration diagram showing a conventional shadow mask inspection apparatus.

FIG. 12 is a diagram showing an example of a shadow mask displayed on the screen of a conventional shadow mask inspection apparatus.

FIG. 13 is a diagram showing a dimensional relationship of slit holes at the time of inspection of a conventional shadow mask inspection device.

[Explanation of symbols]

 1 light source 2 light receiving means 3 computing means 4 shadow mask 5 incident light 6 transmitted light 7 moving means 8 opening hole 9 moving direction 10 small area (measurement area)

Front Page Continuation (72) Inventor Kunio Takeoka No. 1 Baba Institute, Nagaokakyo City Mitsubishi Electric Co., Ltd.

Claims (10)

[Claims] 1. A light source disposed on one side of a shadow mask, and a light source passing through a hole in a measurement area set on the other side of the shadow mask and set on the shadow mask. Light receiving means for receiving light and generating an electric signal corresponding to the received light quantity, moving means for changing the relative position of the shadow mask and the light receiving means to move the measurement area, and movement of the measurement area A shadow mask inspecting apparatus, comprising: a calculation unit that calculates a change in an electric signal from the light receiving unit and calculates and outputs a distribution of transmittance in a measurement region. 2. A light source arranged on one side of a shadow mask, and a light source arranged on the other side of the shadow mask and passing through a hole in an image area including a measurement area set on the shadow mask. Light receiving means for receiving the passing light from the light source and generating a video signal corresponding to its luminance distribution, moving means for moving the video area by changing the relative position of the shadow mask and the light receiving means, and the video area A shadow mask inspecting apparatus for calculating and outputting a distribution of transmittance in the measurement region from an image of the image signal that changes with the movement of the shadow mask. 3. The shadow mask inspection apparatus according to claim 1, further comprising a detection unit that detects a defect in the shadow mask based on a calculation result from the calculation unit. 4. The optical path direction from the light source to the light receiving means and the shadow mask surface direction are arranged substantially perpendicular to each other, and the measurement area includes the optical path in the area and the moving direction of the moving means is set to the moving direction. 3. The shadow mask inspection device according to claim 1, wherein the shadow mask is in a direction parallel to the shadow mask, and the calculation means is configured to calculate a distribution of transmittance along the movement direction. 5. The spot type luminance meter is used as the light receiving means,
The shadow mask inspection apparatus according to claim 1 or 2, wherein the spot-type luminance meter is arranged such that a plurality of holes are included in the measurement region. 6. The light-shielding tube luminance meter is used as the light-receiving means, and the light-shielding tube luminance meter is arranged so that a plurality of holes are included in the measurement region. Shadow mask inspection system. 7. A light source for emitting condensed light from the light source, wherein a spot formed on the shadow mask by the irradiation light from the light source has a spot size including a plurality of holes of the shadow mask. The shadow mask inspection apparatus according to claim 1, wherein the light source and the shadow mask are arranged. 8. The shadow mask inspection apparatus according to claim 1, wherein the light source is a diffused light source that emits light diffused in a direction normal to a light emitting surface of the light source. 9. An optical path direction from the light source to the light receiving means and a surface direction of the shadow mask are arranged substantially perpendicularly, and a moving direction of the measurement region by the moving means includes the optical path and is substantially perpendicular to the optical path. 3. The shadow mask inspection apparatus according to claim 1, wherein the light source and the light receiving means are arranged so as to face each other in a line shape in a direction substantially perpendicular to the optical path direction and the moving direction. 10. The degree of light passing through a hole in a measurement area set on a shadow mask is obtained as a transmittance, and the measurement area is moved to calculate a distribution of the transmittance in the area. A method for inspecting a shadow mask according to claim 1, wherein the shadow mask is inspected for uneven defects.