JPH0933234A - Method and apparatus for inspection of through hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the inspection of the surface state of a circumferential wall face of a through hole in a through hole plate and to enhance the accuracy of the inspection. SOLUTION: Regarding a first main face (a main face on the side where an opening area is wide) and a second main face (a main face on the side where opening area is narrow) on a shadow mask SM, a prescribed number of first main-face gradation data and second main-face gradation data are obtained from a live image. Both image data are shading-corrected (S132 to S137), and a noise which is caused by a light source or the like is removed. Then, the first main-face gradation data which has been corrected is divided by the second main-face gradation data (S139), and offset gradation data in which data corresponding to the second main-face gradation data has been offset from the first main-face gradation data, is obtained. The offset gradation data is smoothed and processed by a median filter which comprises 31×31 filter windows, and median data which has been smoothed is obtained (S140). After that, the offset gradation data is divided by the median data, standardized data is found (S141), an image is displayed on the basis of the standardized data (S142), and an image from which the grade of the shadow mask SM has been removed and in which an irregularity in light transmittance has been emphasized is displayed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention penetrates a plate-like body,
The present invention relates to an inspection method and an inspection apparatus for a through hole having different hole areas on the front and back main surfaces of the plate-like body, and particularly to a through hole formed in a shadow mask for a color cathode ray tube or an aperture grill for a Trinitron tube (registered trademark). The present invention relates to a through hole inspection method and an inspection device for inspecting the surface state of a peripheral wall surface.

[0002]

2. Description of the Related Art Generally, in a shadow mask or an aperture grill, minute through holes are formed in an approximately periodic array. It is well known that in a through-hole plate such as this shadow mask, not only the shape of the through-holes and the state of the through-hole peripheral wall surface, but also the periodic repetition of the array of through-holes greatly affects the quality. ing. Therefore, it is indispensable to improve the process control in the process of forming the through holes and to inspect the peripheral wall surface of the through holes.

By the way, in a shadow mask, for example, a large number of through holes are formed in a metal thin plate by arranging them almost periodically by using a photoetching method.
Moreover, since the electron beam emitted from the electron gun strikes the shadow mask obliquely toward the end of the cathode ray tube, a through hole is intentionally formed in the shadow mask so that the center of the front hole diameter and the center of the rear hole diameter are different. It Specifically, a method is adopted in which the photo-etching from the front side and the photo-etching from the back side of the shadow mask material are separately performed so as to have different degrees of etching.

When this front and back photo etching is performed, as shown in the sectional view of FIG. 20 and the front view of FIG. 21, the opening diameter of the hole becomes large on the first main surface S1 side which is one main surface side. A through hole 200 having a smaller diameter on the second main surface S2 side, which is the other main surface side, is formed penetrating the metal thin plate 202. When the etching on both main surfaces progresses ideally, the peripheral wall surface 203 of the through hole 200 does not suffer from defects such as irregularities or discoloration, regardless of whether the opening diameter is on the large diameter side or the small diameter side. The surface state of the wall surface 203 becomes extremely favorable.

In this etching step, the etching solution may not be evenly spread over the main surface of the metal thin plate, or a coating step of applying a resist having etching resistance, which is a step before the etching step, to the main surface of the metal thin plate. In the above, the resist may not be uniformly applied to the main surface of the metal thin plate, and the film thickness of the resist film formed on the metal thin plate may become uneven. In addition, the composition of the metal thin plate that is the shadow mask material is not always uniform, and the composition may vary within the thin plate. When such a situation is reached, the film thickness of the resist film and the uniformity of etching are impaired. Therefore, in a portion where the film thickness, composition, etc. are not uniform, as shown in the sectional view of FIG. 22 and the plan view of FIG. In addition, irregularities 204 and discolored portions 206 occur on the peripheral wall surface 203 of the through hole 200. In addition, this disorder 204 and the discolored portion 20
No. 6 is not solely due to the nonuniformity of the film thickness and composition. That is, if the removal of the etching solution from the thin metal plate by the cleaning is insufficient in the cleaning step that is a step subsequent to the etching step, unexpected etching due to the remaining etching solution may occur.

The irregularity 204 such as unevenness and the generation of the discolored portion 206 are not peculiar phenomena when the front and back surfaces of the thin metal plate are photoetched. That is, even when etching is performed only on the first main surface S1 side to form through holes, the turbulence 204 and the discolored portion 206 may occur due to the reasons described above. The through-hole 200 formed by etching from the first main surface S1 has a large opening diameter on the first main surface S1 side and a small diameter on the second main surface S2 side, as shown in FIG. Through.

Therefore, in the coating process and the etching process, the uniform application of the resist and the etching solution and in the cleaning process the ensuring of sufficient cleaning is the most important in controlling the process. However, even if thorough process control is performed in each process, it is difficult to eliminate local nonuniformity of film thickness due to the influence of environmental temperature and the like. Further, the homogenization of the composition of the metal thin plate depends on various conditions in the manufacturing process, for example, melting temperature, rolling conditions, etc., and the metal thin plate whose composition is completely uniform should always be used for the shadow mask material. It is difficult. For this reason, after the etching / cleaning is finished, the surface state of the peripheral wall surface 203 of the through hole 200 is inspected for the shadow mask from which the resist film has been peeled off and cut into individual sheets, and the peripheral wall surface 203 has a disorder 204 or a discolored portion 206. Elimination of defective products. By this inspection, it is possible to determine not only the occurrence of a process defect in each process but also the occurrence of a composition defect of the metal thin plate. Therefore, since the inspection result can be reflected in the process control and the material quality control, the inspection of the peripheral wall surface of the through hole is extremely important.

In the inspection of the peripheral wall surface of the through hole, a method of inspecting the unevenness of the light transmittance or the light reflectance (hereinafter, simply referred to as unevenness) due to the surface condition of the peripheral wall surface of the through hole is adopted. More specifically, as shown in FIG. 25, first,
The inspector holds the shadow mask SM by hand, and arranges the shadow mask SM diagonally in front of the translucent inclined table surface 214 of the light table 212 having a built-in light source (not shown). Then, the light from the light source is directed to the inclined table surface 21.
The shadow mask SM is irradiated via 4 and the shadow mask SM is visually observed while shaking the shadow mask SM as indicated by an arrow in the figure. At this time, in the shadow mask SM, if irregularities or the like are disturbed on the peripheral wall surface of the through hole or a defect such as a discolored portion is generated, the defective through hole is not covered by the uneven portion or the discolored portion on the peripheral wall surface. Since the light reflection state is different from that of the portion, the light reflection state is different even for the through hole which does not have the defect or whose degree is low. In a shadow mask SM in which the through holes are finely arranged in a substantially periodic manner, it is relatively rare that a defect occurs only in the peripheral wall surface of one through hole, and the through holes in the periphery thereof are relatively small. However, there are many differences in the degree, and similar defective peripheral wall surfaces often occur.

Therefore, when the shadow mask SM having a through hole having a defective peripheral wall surface is visually inspected as described above, the shadow mask SM is a non-defective product (so-called limit sample) having a transparent hole having no peripheral wall defect or having a low degree. In contrast, the inspector recognizes as spots where the through holes having defective peripheral wall surface are gathered and the light reflection state is different. This unevenness is
The manner of occurrence differs depending on the existence state of the through hole having the defective peripheral wall surface in the shadow mask SM as follows. For example, when the defective areas of the through holes having a certain number of defective holes on the peripheral wall are scattered over the entire surface of the shadow mask SM, the inspector determines that the unevenness of light is uneven. recognize. In addition, in the case where the through hole defective region is sparsely present in the shadow mask SM in a relatively wide region, the inspector
The light and shade unevenness is recognized as partial unevenness. Further, it may be recognized as uneven streaks in which light and shade unevenness occurs linearly in the vertical or horizontal direction.

[0010]

However, the above-mentioned inspection has the following problems because of the visual judgment of the inspector.

Even a non-defective shadow mask SM has some through-hole regions, and some unevenness is allowed. Moreover,
In addition to this unevenness, the inspector also sees the amount of light itself that has passed through the through hole. Further, in the inspection, the unevenness occurring in the non-defective shadow mask SM and the unevenness occurring in the shadow mask SM to be inspected are not compared, but the empirically recognized comparison with the unevenness of the non-defective shadow mask SM is performed. The inspection was performed while visually checking the unevenness of the shadow mask SM to be inspected. Therefore, a high degree of skill and considerable experience are required to judge the quality by comparing the non-defective product with the unevenness of the shadow mask SM to be inspected. In addition, even if the degree of skill and experience are almost the same,
Depending on the inspector's individual difference and health condition, the quality judgment may vary.

Further, the above-mentioned unevenness is not recognized by an inspector unless a certain number of through holes having defective peripheral wall surfaces are gathered. Therefore, in the case where the peripheral wall defective through holes are very sparsely present, in other words, when the peripheral wall defective in a single through hole is inspected, this peripheral wall defective is recognized as optical unevenness. However, it was difficult to inspect the peripheral wall surface of the through hole.

The present invention has been made to solve the above-mentioned problems, and the through-holes which penetrate the plate-like member and have different hole areas on the front and back main surfaces of the plate-like member have different surface states of the peripheral wall surface. The purpose is to simplify inspection and improve inspection accuracy.

[0014]

Means for Solving the Problem and Its Action / Effect To solve the above-mentioned problems, the inspection method for a through hole according to the first aspect of the invention is such that the plate-shaped body is penetrated and main surfaces of the front and back sides of the plate-shaped body are penetrated. In the method for inspecting through holes having different hole areas, the first irradiation step of irradiating with light necessary for capturing an image of the through holes from the first main surface side which is the main surface of the plate-shaped body having the larger hole area. And the first
The first imaging step of imaging the through hole from the side of the first main surface irradiated with light in the irradiation step to obtain the first gradation data which is the light amount distribution of the captured image; From the second main surface side which is the main surface of the plate-shaped body, the second irradiation step of irradiating the light necessary for imaging the through hole, and from the second main surface side to which the light is irradiated by the second irradiation step. A second imaging step of imaging the through hole and obtaining second gradation data which is a light amount distribution of the captured image, and the first gradation data and the second gradation data are compared, and the first floor is compared. An offsetting step of obtaining the third tone data by offsetting the data corresponding to the second tone data from the tone data, and the surface condition of the peripheral wall surface of the through hole in the plate-shaped body based on the third tone data. And a detection step of detecting.

In order to solve the above-mentioned problems, the through hole inspection apparatus according to the second aspect of the present invention includes a through hole which penetrates the plate-shaped member and has different hole areas on the front and back main surfaces of the plate-shaped member. In an inspection device, for imaging a through hole from a support means that supports the plate-shaped body and a first main surface side that is a main surface of the plate-shaped body supported by the support means on the side where the hole area is large. The first irradiation unit that irradiates the required light and the through hole is imaged from the side of the first main surface irradiated with the light by the first irradiation unit, and the first gradation data that is the light amount distribution of the captured image is obtained. A first imaging means and a second irradiation means for irradiating the plate-shaped body supported by the supporting means with light required to image the through hole from the second main surface side which is the main surface on the side where the hole area is small. And the through hole is imaged from the second main surface side where the light is irradiated by the second irradiation means, and the light amount distribution of the captured image is obtained. The second image pickup means for obtaining the second gradation data is compared with the first gradation data and the second gradation data to cancel the data corresponding to the second gradation data from the first gradation data. The offsetting means for obtaining the third gradation data and the detecting means for detecting the surface condition of the peripheral wall surface of the through hole in the plate-shaped body based on the third gradation data.

In the through hole inspection method of the first invention or the through hole inspection apparatus of the second invention having the above-described structure, first, it is necessary to image the through hole from the first main surface side of the plate-shaped body. Light is emitted. The through hole is imaged from the side of the first main surface irradiated with this light, and the first gradation data, which is the light amount distribution of the captured image of the first main surface, is obtained. Next, the light required to image the through hole is emitted from the second main surface side of the plate-shaped body. The through hole is imaged from the side of the second main surface irradiated with this light, and the second gradation data which is the light amount distribution of the captured image of the second main surface is obtained.
The first gradation data and the second gradation data, which are the above-mentioned light amount distributions, are obtained as the density values of the pixels. Also,
The image pickup from each main surface side may be an image (transmission light image pickup) when light is irradiated so as to pass through the through holes of the plate-shaped body, and the light is reflected on each main surface side. It is also possible to use imaging when reflected (imaging of reflected light).

In the case of transmitted light imaging, the first gradation data representing the light amount distribution of the imaged image from the side of the first main surface includes, as shown in FIG. 1, which is an optical path diagram of transmitted light illumination at the time of imaging. Through hole H
The total amount of light that has entered from the side with the smaller hole area and that has passed through the through hole H without being reflected by the peripheral wall surface W, and the light amount distribution obtained by the light that has reflected through the peripheral wall surface W and transmitted through the through hole H. reflect. Moreover, since the peripheral wall surface W is inclined, the traveling direction of the light after being reflected by the peripheral wall surface W is on the first main surface S1 side, and almost all of the light reflected by the peripheral wall surface W is the first main surface S1. The light is transmitted through the opening on the S1 side. On the other hand, as shown in FIG. 2 which is an optical path diagram of transmitted light illumination when capturing an image from the second main surface S2 side,
Even in the second gradation data representing the light amount distribution of the captured image from the main surface S2 side, the light penetrates through the through hole H without entering the through hole H from the side having a large hole area and being reflected by the peripheral wall surface W. All of the reflected light and the light amount distribution obtained by the light reflected by the peripheral wall surface W and transmitted through the through hole H are reflected. However, since the peripheral wall surface W is inclined, the traveling direction of light after being reflected by the peripheral wall surface W is the first.
Most of the light on the main surface S1 side and reflected by the peripheral wall surface W does not pass through the opening on the second main surface S2 side.

Therefore, if the data corresponding to the second grayscale data is canceled from the first grayscale data by comparing the second grayscale data and the first grayscale data, the first grayscale data is converted into the second grayscale data.
The light amount distribution obtained by all the light transmitted through the through hole H without reflection of the gradation data and a part of the light reflected by the peripheral wall surface W and transmitted through the through hole H is excluded. Therefore, the third gradation data reflects only the light amount distribution obtained only by the light reflected by the peripheral wall surface W and transmitted through the through hole H. Then, based on the third gradation data, the surface state of the peripheral wall surface W of the through hole H reflected in the data is detected. As a result of the detection, the state of reflection of light on the peripheral wall surface W, That is, only the surface state of the peripheral wall surface W of the through hole H can be obtained.

In the case of the reflected light image pickup, as shown in FIG. 3 which is an optical path diagram of the reflected light illumination when the image is picked up from the first main surface S1 side, the first gradation data includes the first main surface S1. The light quantity distribution of the reflected light and the light scattered on the peripheral wall surface W is reflected. on the other hand,
As shown in FIG. 4, which is an optical path diagram of reflected light illumination when capturing an image from the second main surface S2 side, the second gradation data reflects the light amount distribution of only the light reflected by the second main surface. It Therefore,
The light intensity distribution of only the light scattered on the peripheral wall surface W is reflected in the third gradation data obtained by canceling the data corresponding to the second gradation data from the first gradation data.

Therefore, in the above-described inspection method for a through hole according to the first invention or the inspection device for a through hole according to the second invention, the data reflects only the state of reflection on the peripheral wall surface of the through hole. The surface condition of the peripheral wall surface of the through hole is detected based on the gradation data. Therefore, according to the through hole inspection method of the first invention or the through hole inspection apparatus of the second invention, the inspection of the surface state of the peripheral wall surface of the through hole can be simplified and the inspection accuracy is improved. Can be made.

In the structure of the above-mentioned first invention, the plate-shaped body is a through-hole plate in which a plurality of through-holes are arranged in a substantially periodic manner, and the first imaging step is performed by the first irradiation step. A step of imaging a plurality of through holes within a predetermined range of the through hole plate from the side of the first main surface where light is irradiated, and obtaining first gradation data which is a light amount distribution of the picked-up image, In the second imaging step, a plurality of through holes within a predetermined range of the through hole plate are imaged from the second main surface side where light is emitted in the second irradiation step, and a light amount distribution of the captured image is obtained. Is a step of obtaining the second gradation data.

Further, in the above-mentioned configuration of the second invention,
The plate-shaped body is a through-hole plate in which a plurality of through-holes are arranged in a substantially periodic manner, and the first image pickup means transmits the light from the first main surface side irradiated with light by the first irradiation means. The second image capturing unit is a unit that captures a plurality of through holes in a predetermined range of the aperture plate and obtains first gradation data that is a light amount distribution of the captured image. It is a means for imaging a plurality of through holes within a predetermined range of the through hole plate from the side of the irradiated second main surface to obtain second gradation data which is a light amount distribution of the picked-up image.

In the through-hole inspection method or inspection apparatus having these configurations, the through-hole plate in which a plurality of through-holes are arrayed approximately periodically is determined from the side of the first main surface where light is irradiated. By imaging a plurality of through holes within the range, it is possible to obtain the first gradation data which is the light amount distribution of the captured image. In addition, a plurality of through holes within a predetermined range of the through hole plate are imaged from the second main surface side where light is radiated, and the light amount distribution of the captured image is the second
It is possible to obtain gradation data. Therefore, according to the through hole inspection method or inspection apparatus having these configurations, the surface state of the peripheral wall surface W can be detected for each of the plurality of through holes in the predetermined range of the through hole plate.

In the structure of the first aspect of the invention, the detecting step is a display step of displaying the peripheral wall surface of the through hole in the plate-shaped body based on the third gradation data.

Further, in the configuration of the above second invention,
The detection means is a display means for displaying the peripheral wall surface of the through hole in the plate-shaped body based on the third gradation data.

According to the inspection method or the inspection apparatus for the through-holes having these configurations, since the image based on the third gradation data is displayed, the inspector can image the surface condition of the peripheral wall surface for a predetermined number of through-holes. Can be provided as each.

In the configuration of the above-mentioned first invention, the detecting step includes a smoothing step of smoothing the third gradation data by a predetermined filter to obtain smoothed data, and the third gradation data. The method includes a standardization step of dividing the smoothed data to obtain standardized data, and a display step of displaying an image based on the standardized data.

Further, in the above-mentioned second invention,
The detecting means smoothes the third tone data by a predetermined filter to obtain smoothed data, and the smoothing means divides the third tone data by the smoothed data to obtain standardized data. It has a normalizing means and a display means for displaying an image based on the standardized data.

In the through hole inspection method or inspection apparatus having these configurations, the third gradation data of a plurality of through holes in a predetermined range of the through plate is smoothed by a predetermined filter to obtain smoothed data, The third gradation data is divided by the smoothed data to obtain standardized data, and an image based on the standardized data is displayed. The displayed image is based on the standardized data obtained by dividing the third gradation data by the smoothed data. Therefore, according to the inspection method or the inspection apparatus for the through holes having these configurations, the distribution of light and dark according to the density of the arrangement of the through holes is removed, and the light transmittance or the light caused by the surface state of the peripheral wall surface of the through holes is reduced. It is possible to provide an inspector with an image in which unevenness of reflectance is emphasized.

In the configuration of the second aspect of the invention, the predetermined filter used when the smoothing means performs the smoothing process is:
It is a median filter having a filter window of a predetermined size.

In the inspection apparatus for a through hole having this structure, noise having a high spatial frequency is effectively reduced from the third gradation data, and smoothed data in which small fluctuations are smoothed can be obtained. Therefore, according to the inspection device for a through hole having this configuration, it is possible to provide the inspector with an image in which the unevenness of the light transmittance or the light reflectance due to the surface state of the peripheral wall surface of the through hole is further emphasized.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described based on an embodiment of a shadow mask inspection apparatus. First, the external structure of the shadow mask inspection apparatus 30 of this embodiment will be described. As shown in the front view of FIG. 5, the shadow mask inspection apparatus 30 includes an optical measuring apparatus 40 for capturing an image of the shadow mask SM and obtaining image data, and a data processing apparatus 50 for performing various data processing based on the image data. It is composed of.

The optical measuring device 40 includes a surface plate 41, and an opening for allowing illumination light to pass through is formed in the upper surface of the surface plate 41 at substantially the center. A diffusion plate 43 (for example, a glass plate or a plastic plate) that diffuses and transmits light is placed on the upper surface of the surface plate 41.
A light source 44 is disposed below the light source 3. This light source 4
As 4, a high-frequency lighting fluorescent lamp is used, for example. The mask plate 45 (see FIG. 6) is provided on the upper surface of the diffusion plate 43.
(See) is positioned and placed / fixed, and the shadow mask SM is closely attached / fixed to the mask plate 45 with an adhesive tape or the like. Since the shadow mask SM is positioned in this way, even if it is inverted and the shadow mask SM is fixed as described later, its position does not change before and after the inversion. The shadow mask SM is, as shown in FIG. 1, firstly, the first main surface S on the side where the opening area of the through hole H is large.
Fixed with 1 on top. Further, after a predetermined process described later, the shadow mask SM is inverted, and as shown in FIG. 2, the shadow mask SM is fixed with the second main surface S2 on the side where the opening area of the through hole H is small facing upward.

A stand support arm 46 extending upward is provided upright from the surface plate 41, and the stand support arm 4 is provided.
6, a camera holding beam 47 is provided so-called cantilever. Further, since the camera holding beam 47 is attached to the stand supporting arm 46 so as to be adjustable by an adjustment mechanism (not shown), the camera holding beam 47 and the CCD.
The camera 49 and the camera 49 can be moved together in the vertical direction (Z direction in the drawing). Further, the CCD camera 49 is adjustably attached to the camera holding beam 47, and the CCD camera 49 can be moved in the left-right direction (X direction in the drawing). Therefore, the CCD camera 49 can be moved vertically and horizontally so that the areas to be imaged by the shadow masks of various sizes and the imaging area of the CCD camera 49 coincide with each other.

The CCD camera 49 is a CCD camera in which CCD elements are two-dimensionally arranged, and is capable of digitally outputting 10 bits of light and shade of an image in a light and shade range. Note that CC
An image of 1,534 pixels × 1,024 pixels can be acquired from the D camera 49.

The data processing device 50 comprises a display 52 for displaying an image to be described later, an image processing device 54 for performing various image processes, and a camera control device 62 for controlling the gain and shutter speed of the CCD camera 49. There is.

Next, the electrical configuration of the shadow mask inspection apparatus 30 will be described with reference to the block diagram of FIG. The light emitted from the light source 44 sequentially passes through the diffusion plate 43 and the through hole of the shadow mask SM and enters the CCD camera 49. At this time, the shadow mask SM is brought into close contact with and fixed to the mask plate 45, and the through hole region SMe, which is a region where the through hole of the shadow mask SM is formed, is the opening 45 of the mask plate 45.
The peripheral region of the shadow mask SM exposed from a and having no through hole is masked. Therefore, the CCD camera 49 images the shadow mask SM with respect to the through hole area SMe, and the two-dimensionally arranged grayscale image (multivalued image).
Image data Di. This image data Di is
After being captured by the image processing device 54 via the camera control device 62 and subjected to image processing described later, various images are displayed on the display 52.

The image processing device 54 is a general-purpose high-speed image processing device that performs various processes according to a pre-registered program, and a CPU 66 that performs various other image processes and other predetermined processes, and an image. Main storage device 68 such as RAM for temporarily storing data such as data Di
A keyboard 70 for inputting data, an auxiliary storage device 72 for storing data such as image data Di, such as a flexible disk device, and a printer 74 for issuing inspection results and the like. They are connected to each other via a bus line 64. In addition, the camera control device 62 is connected to the bus line 64 of the image processing device 54.
And the display 52 are connected.

Next, the through hole inspection process performed by the shadow mask inspection apparatus 30 of this embodiment will be described with reference to the flowcharts of FIG.

The flow chart of FIG. 7 shows an outline of the through hole inspection processing of the shadow mask SM performed in this embodiment. When the processing is started, the initialization necessary for the subsequent processing is performed. (Step S100). For example,
In this inspection, the setting (initial setting) of the limit sample shadow mask SM, which is the standard for determining the quality of unevenness (unevenness of light transmittance due to the disturbance of light reflection on the peripheral wall surface of the through hole), and the initial stage of the inspection start The screen is displayed on the display 52, and the memory area used in the processing described later is cleared.

When this initialization is performed, the display 52
An initial setting screen is displayed on the screen, and the input locations of various items (initial setting items) required in the process of the subsequent inspection processing remain uninput on the initial setting screen. Further, upon receiving the initial setting of the limit sample shadow mask SM, the display image data of the unevenness of the limit sample shadow mask SM is read out for each of the initially set limit sample shadow masks SM. The unevenness image for each shadow mask SM of the limit sample is displayed on the display 52 based on the read-out display image data when the necessary items are set in the initial setting described later. It should be noted that the display image data of the unevenness of the shadow masks SM of the respective limit samples has a degree of unevenness within a permissible range of the quality of the shadow mask and a plurality of shadow masks SM having different degrees of unevenness, or the degree of unevenness. Is a range in which the quality of the shadow mask is unacceptable and is obtained in advance in the same manner as the shadow mask SM to be inspected to be described later for a plurality of shadow masks SM having different degrees, and auxiliary storage is performed for each shadow mask SM of the limit sample. Stored in device 72.

Subsequent to step S100, various items required in the inspection process are initialized (step S110). In this initial setting, data is sequentially input to the initial setting items on the initial setting screen that is displayed with no data input in the initialization process. That is, as shown in the flowchart of FIG. 8 showing the detailed processing of the initialization processing, the output file name of the inspection result (step S11
1), the mask type of the mask plate 45 used for masking the shadow mask SM to be inspected (step S11
2), The inspector name (step S113) is sequentially input.
These are posted on the inspection result displayed or printed out after the inspection is completed. The output file is a file for storing the inspection result for each shadow mask SM to be inspected, and the data format thereof is the sample ID (for example, manufacturing serial number) of the shadow mask SM to be inspected and the inspector name. , It is constructed so that the inspection date etc. can be saved.

When these inputs are completed, the process waits until the inspection start switch is pressed (step S114). When the inspection is started, the output file is opened (step S115) to prepare for the output of the inspection result. After that, the initial setting data such as the input output file name is output (step S116), the initial setting data is displayed on the initial setting screen of the display 52, and the result input screen is set (step S117). Subsequently, the uneven image for each shadow mask SM of the limit sample that has been initialized is displayed on the display 5 based on the read display image data.
2 is displayed (step S118). In this case, if a plurality of limit samples are set, the uneven images of the shadow masks SM of the plurality of limit samples are divided and displayed on the display 52 at the same time. Next, a result input screen for inputting the result of the quality judgment of the shadow mask SM to be inspected and the like is displayed on the display 52 together with the unevenness images of the shadow masks SM of the plurality of limit samples (step S1).
19).

Display 52 by this initialization processing
The state of image display on the screen is as shown in the schematic diagram of FIG. That is, the four initially set shadow masks SM
Uneven image SMG1, SMG2, SMG about
3, SMG4 and the result input screen RG are divided and displayed in the display area 52a of the display 52 at the same time. Since the nonuniformity images SMG1 to SMG4 are based on the display image data, each nonuniformity image can be enlarged and displayed individually by the enlargement processing (not shown) in the image processing device 54. In addition, the uneven images SMG1 to SMG4
Is a limit sample unevenness image with respect to the unevenness image of the shadow mask SM to be inspected.

The uneven image S of the limit sample displayed in this way
MG1 to SMG4 are non-uniformity images of the shadow mask SM of the limit sample initialized in step S100 and differ depending on this initialization. For example, if four shadow masks SM having different degrees of overall unevenness in which light and dark unevenness are scattered are set in the initial setting, unevenness images having different degrees of overall unevenness are displayed in stages. Also, the default shadow mask SM is a shadow mask SM with good overall unevenness.
With the shadow mask SM having good partial unevenness, the shadow mask SM having good vertical unevenness, and the shadow mask SM having good horizontal unevenness, uneven images of these different unevennesses are displayed.

Subsequent to the above-mentioned initial setting, the completion of setting the shadow mask on the diffusion plate 43 on which the mask plate 45 is placed by the inspector is waited for, and the input start instruction issued by the switch operation after completion of the setting is waited. Yes (Step S
120). If there is an input start instruction, the image of the shadow mask SM is input / visualized (step S).
130). The light source 44 is controlled to be turned on prior to the input / visualization processing.

In this input / visualization processing, the transmission images from the front and back of the shadow mask SM to be inspected are taken in and various processing for displaying the uneven image is performed. That is, as shown in the flowchart of FIG. 10 showing the detailed processing, first, the CCD camera 49 is set so as to match the image capturing conditions when capturing the transmission image of the shadow mask SM with the CCD camera 49 (step S13).
1). More specifically, the shutter speed and the gain of the CCD camera 49 are set on the basis of the predetermined imaging conditions such as the shutter speed, the gain and the focus, and the through hole area SMe of the through hole of the shadow mask SM to be inspected. , Focus adjustment and Z of CCD camera 49
Axial position adjustment is performed. The Z-axis position adjustment is performed by manually operating an adjustment mechanism (not shown) to adjust the stand support arm 46.
On the other hand, the camera holding beam 47 and the CCD camera 49 are integrally moved in the vertical direction, and shutter speed setting, gain adjustment, and the like are performed by the camera control device 62. The focus adjustment is performed by manually adjusting the lens unit 77 of the CCD camera 49. In this case, the focus of the CCD camera 49 is adjusted so as to blur in order to remove moire that occurs between the pixel array of the CCD camera 49 and the periodic arrangement of the through holes of the shadow mask SM.

When the image pickup conditions of the CCD camera 49 are set in this manner, image pickup from the front surface (first main surface) and back surface (second main surface) of the shadow mask SM is started as follows. It That is, first, as shown in FIG.
The CCD camera 49 images the shadow mask SM on the diffusion plate 43 from the side of the first main surface S1 of the shadow mask SM on the side where the opening area of the through hole H is large, and the CCD mask 49 is illuminated by the light source 44 and the through hole of the shadow mask SM. A transmission image of light transmitted through H (hereinafter referred to as a raw image) is captured (step S13).
2). Then, the CCD camera 49 uses the shadow mask S
The M first main surface raw image is output to the main storage device 68 via the camera control device 62 and the bus line 64 as digital gradation data with a digital output of 1,534 pixels × 1,024 pixels and a gradation range of 10 bits. Hereinafter, in order to distinguish the raw image and the gradation data to be output on the first principal surface side captured in step S132 from the raw image and the gradation data on the second principal surface side, respectively, the first principal surface raw image , The first principal surface gradation data.

Generally, the intervals between the large numbers of through holes formed in the shadow mask SM are narrow in the central portion of the shadow mask and widen in the peripheral direction. This is because the arrangement of the through holes of the shadow mask SM is designed in consideration of forming the flat shadow mask SM into a dome shape. From this, the shadow mask S
The above-described first principal surface gradation data, which is the data of the transmission image or the reflection image of M, is bright in the central portion of the shadow mask SM and becomes darker in the peripheral direction in accordance with the density of the arrangement of the through holes of the shadow mask SM. The light and dark patterns (hereinafter, this pattern is referred to as grade) are data represented as a light and shade range. Moreover, in the first gradation data, the penetrating hole H is entered from the side having the smaller hole area and the peripheral wall surface W
All of the light that has passed through the through hole H without being reflected by and the light amount distribution obtained by the light that has been reflected by the peripheral wall surface W and transmitted through the through hole H are reflected. That is, the first main surface gradation data in this embodiment corresponds to the first gradation data according to the present invention.

Then, the first principal plane gradation data of this first principal plane raw image is passed through the camera control unit 62 and the image processing unit 5
4 and is displayed on the display 52. Thereby, the image pickup area of the CCD camera 49 can be confirmed.

When the first principal surface gradation data is sent to the image processing device 54 in this manner, the image processing device 54 performs image compression by grouping 4 × 4 pixels of the image (step S133). First main surface grayscale data (1,534 pixels × 1,024 pixels × 10 bits; data size is 16 bits = 2 bytes) of the first main surface raw image is 320 × 256 ×
It is compressed into 14-bit data (data size is the same). By performing this image compression, it is possible to shorten the data processing time when filtering with a median filter described later.

The output signal of the first main surface raw image obtained by the CCD camera 49 is superposed with a signal resulting from uneven light emission distribution caused by the light source 44 or the diffusion plate 43 itself, uneven sensitivity of the image pickup system and the like. Therefore, the above step S133
Then, the compressed image data (first main surface gradation data) is divided by reference data (gradation data; 320 × 256 × 2 bytes) with the same number of data to perform shading correction (step S134). And
The first main surface gradation data after the shading correction is temporarily stored in the main storage device 68. The reference data is gradation data of an image previously captured with the shadow mask SM not placed on the diffusion plate 43 and only the mask plate 45 placed, and is stored in the main storage device 68 in advance. Therefore, this reference data is read during shading correction.

When the image pickup from the first main surface side and the data processing are completed in this way, the subsequent processing is temporarily interrupted, and the inspector waits for the inversion set of the shadow mask SM.
That is, as shown in FIG. 2, the shadow mask SM is the second shadow mask SM on the side where the opening area of the through hole H is small.
It is placed with the main surface facing the CCD camera 49. And
After imaging from the second main surface side, the above step S1 is performed.
Similar to 32 to 134, the second main surface raw image is captured, the second main surface gradation data is output (step S135), the image is compressed (step S136), and the shading correction / storage (step S137) is performed.

This second main surface gradation data is also data in which the grade is expressed as a light and shade range. In the second main surface gradation data, the perforation H is entered from the side having a larger hole area W and the peripheral wall surface W is entered. All of the light transmitted through the through hole H without being reflected by
The light amount distribution obtained by a part of the light reflected by the peripheral wall surface W and transmitted through the through hole H is reflected. That is, the second main surface gradation data in this embodiment corresponds to the second gradation data referred to in the present invention.

As described above, the first CCD camera 49 is used.
Since the shadow mask SM is inverted to capture the second principal surface raw image after capturing the principal surface raw image, the coordinates of the second principal surface gradation data are also inverted with respect to the coordinates of the first principal surface gradation data. are doing. Therefore, the coordinates of the second principal surface gradation data are converted so that the coordinates of the second principal surface gradation data and the coordinates of the first principal surface gradation data are matched (step S138). The coordinates of the first principal surface gradation data may be converted so that the coordinates of the second principal surface gradation data and the coordinates of the first principal surface gradation data are matched. This is to facilitate the division process in step S139 described later.

Subsequent to step S138, the shading-corrected first and second principal surface gradation data are read, and the read first principal surface gradation data is divided by the second principal surface gradation data (step S139). ). The grayscale data calculated by the division with the second main surface grayscale data (hereinafter referred to as offset grayscale data to distinguish it from the first and second main surface grayscale data) is a single As shown in FIG. 11, which is a schematic view of the through hole H, the through hole H does not reflect on the peripheral wall surface W.
The data is obtained by excluding the light amount distribution obtained from all the light that has passed through and the part of the light that has been reflected by the peripheral wall surface W and transmitted through the through hole H. Therefore, the offset gradation data is gradation data that reflects only the light amount distribution obtained only by the light reflected by the peripheral wall surface W and transmitted through the through hole H. That is, the offset gradation data in this embodiment corresponds to the third gradation data in the present invention. In this division operation, when the data value of the second principal surface gradation data is zero, the division with the corresponding data is not performed and the value of the first principal surface gradation data is adopted.

Subsequent to this step S139, the offset gradation data is set to 31 pixels × 31 pixels (hereinafter, simply 31 × 31 pixels).
Image correction for smoothing is performed by a median filter having a filter window of
140), to obtain the median data in which the offset grayscale data is smoothed. The smoothing processing at this time is performed by arranging the data (each data of the offset gradation data) that fills each data window of the 31 × 31 filter window in the order of their size to create a data row, and position the center of the data row. The processing that uses the data coming in as the output value is one processing unit. Then, for the offset gradation data, while changing the filtering area of the median filter, for example, the filter window is moved by one pixel in a predetermined direction, and the processing of one processing unit is performed over the data area of the gradation data. repeat.

By the smoothing processing by this median filter, noise having a high spatial frequency is effectively reduced from the offset gradation data. Further, smoothed data of an image in which small fluctuations are smoothed can be obtained. Although the smoothing data reflects the grade and large fluctuations of the shadow mask SM, the unevenness of the shadow mask SM is reduced or eliminated as noise or small fluctuations.

After that, the shadow mask SM to be inspected
The following data conversion is performed to display only the unevenness of No. as an image (step S141). That is, the offset gradation data is divided by the smoothed data that has been smoothed by the median filter to obtain standardized data. In this division operation, if the data value of the smoothed data is zero,
No division is performed on the corresponding data, and the corresponding data of the standardized data is set to the value zero. Since the standardized data thus obtained has undergone division of the offset gradation data in the smoothed data, the grade and large fluctuation of the shadow mask SM reflected in the smoothed data as a shade range are removed, and the through hole H The data represents the unevenness of the light transmittance due to the disturbance of the reflection of light on the peripheral wall surface W of. Since the standardized data obtained by this division is real number data and is difficult to handle in image processing, it is multiplied by a predetermined integer, for example, 4000 to be converted into integer data, to obtain final standardized data.

Next, an image based on this standardized data,
That is, the unevenness of the light transmittance caused by the disturbance of the reflection of light on the peripheral wall surface W of the through hole H is displayed on the display 52 as a unevenness image obtained through the visualization image conversion of the grayscale range data (step S142). The unevenness image S of the inspection target shadow mask SM obtained by this visualization image display processing
MG0 is, as shown in FIG. 12, the uneven image S of the limit sample.
MG1 to SMG4 and the result input screen RG are displayed on the screen of the display 52 which has already been displayed. That is, the mura image SMG0 and the limit sample mura images SMG1 to SMG4
And are simultaneously displayed by being divided on the display 52, and these uneven images are displayed in contrast. Note that the uneven image SMG1 in FIG. 12 is a limit sample (good product) uneven image for overall unevenness, the uneven image SMG2 is a limit sample (good product) uneven image for horizontal unevenness, and the uneven image SMG3 is for vertical unevenness. Is a non-uniform image of the limit sample (non-defective product), and the non-uniform image SMG4 is a non-uniform image of the limit sample (non-defective product) regarding partial non-uniformity.

The unevenness image SMG0 displayed based on the standardized data in the process of step S142 is an image of only the unevenness of the shadow mask SM to be inspected, and the grade is removed, so that the unevenness is emphasized as a result. It will be an image that has been.

Step S1 consisting of the series of processes described above
Following the input / visualization processing of 30, the evaluation result input processing is performed as shown in FIG. 7 (step S145). In this processing, the inspector compares the unevenness image SMG0 of the shadow mask SM to be inspected displayed by the input / visualization processing with the unevenness images SMG1 to SMG4 of the limit samples, and inputs the result. The input items are the sample ID of the shadow mask SM to be inspected, the evaluation result (distinguishing between high-quality non-defective products, medium-quality non-defective products, defective products, etc.), and non-uniformity type (no non-uniformity, total non-uniformity, partial non-uniformity, horizontal non-uniformity, vertical) There are three items: nonuniformity, distinction of other nonuniformity) and nonuniformity occurrence position (division position when the nonuniformity image is divided into 4 × 4). Note that the unevenness occurrence position can be input only when unevenness other than unevenness is input for the unevenness type, and the input can be skipped when there is no unevenness.

Then, when the input of the necessary items is completed and the data storage switch is pressed, these input items are set in the step S for the corresponding shadow mask SM to be inspected.
It is stored in the auxiliary storage device 72 together with the first and second main surface gradation data (320 × 256 × 2 bytes) compressed by 133 and 136. Therefore, when it is desired to display an uneven image again on the shadow mask SM that has been inspected in this way, this data may be read out and the process of step S130 described above may be performed. Further, when the data storage is completed, in preparation for the next inspection of the shadow mask SM, the nonuniformity image SMG0 of the shadow mask SM to be inspected is erased from the display 52, and is calculated for the display of the nonuniformity image SMG0 temporarily. The image data stored in the main memory 68 is erased.

Subsequent to the evaluation result input process in step S145, it is determined whether or not the above-described inspection of the other shadow masks SM needs to be continuously performed (step S150). Then, in the case of continuing the inspection, the above-described processing of steps S120 to S120 is repeated. In addition,
This continuation of the inspection is judged from the pressing condition of a predetermined switch.

As described above, in the shadow mask inspection apparatus 30 of the present embodiment, the cancellation grayscale data reflecting only the light quantity distribution obtained only by the light reflected by the peripheral wall surface W of the through hole H is 31 × 31. Smoothing processing is performed by a median filter having a filter window to obtain smoothed data. Therefore, noise or unevenness as a small fluctuation is effectively reduced or eliminated from the offset gradation data. After that, the offset gradation data is divided by smoothed data to obtain standardized data, and the standardized data is used as data representing unevenness of light transmittance due to disturbance of reflection of light on the peripheral wall surface W. And

Next, based on this standardized data, an image on the first main surface side, that is, an image of unevenness of light transmittance due to disturbance of light reflection on the peripheral wall surface W of the through hole H is obtained as a grayscale range. It is displayed on the display 52 as a non-uniform image obtained through visual image conversion of data. Then, inspect the inspector W
The unevenness of the light transmittance due to the disturbance of the reflection of light in the image can be provided as an image (uneven image). In addition, the provided unevenness image is an image in which unevenness is emphasized as a result because the distribution of light and darkness according to the density of the arrangement of the through holes is removed. Therefore, according to the shadow mask inspection apparatus 30, the unevenness image of unevenness of the light transmittance caused by the disturbance of the reflection of light on the peripheral wall surface W of the through hole H is provided as an image in which the unevenness is emphasized more clearly. By doing so, the inspection accuracy of the visual inspection can be improved.

Further, in the shadow mask inspection device 30,
For the shadow mask SM to be inspected and the shadow masks SM for a plurality of limit samples, a nonuniform image in which only the nonuniformity of the light transmittance due to the disturbance of the reflection of light on the peripheral wall surface W of the through hole H is emphasized is displayed on the display 52. At the same time, the images are compared and displayed, and these uneven images are provided to the inspector. For this reason, the inspector can make a pass / fail judgment of the shadow mask SM by observing only the unevenness with a plurality of limit samples, and does not require a high level of skill or considerable experience. Therefore, according to the shadow mask inspection apparatus 30 of the present embodiment, the visual inspection of the unevenness of the light transmittance due to the disturbance of the light reflection on the peripheral wall surface W of the through hole H of the shadow mask SM is further simplified. In addition, the inspection accuracy of the visual inspection can be dramatically improved. In addition, since there are many uneven images to be compared, the number of judgment items increases, and the inspection accuracy can be further improved.

Further, in the shadow mask inspection device 30,
Evaluation results of the shadow mask SM that was the inspection target and the compressed first principal surface and second principal surface gradation data (320 ×
256 × 2 bytes) is stored in the auxiliary storage device 72. Therefore, even if a follow-up survey or the like is required for the quality of the shadow mask SM, it can be easily dealt with. More specifically, even if the shadow mask SM has a poor quality at a later date, it is pointed out that the unevenness image is displayed again by using the gradation data of the first main surface and the second main surface at the time of inspection. Poor quality and uneven images can be compared. Therefore, the validity of the evaluation and the cause of the quality defect can be investigated.

The shadow mask inspection device 30 described above is used.
Then, the filter window of the median filter is 31 ×
It was fixed at 31. However, this filter window can be modified so as to be variably set depending on the size of the unevenness allowed in the shadow mask SM to be inspected, the type of shadow mask SM, the size of the image at the time of imaging, the resolution of the display 52, and the like. .

Next, another embodiment (second embodiment) will be described. In the second embodiment, a smoothing process by a median filter having a filter window (31 × 31) of m rows and n columns (m and n are natural numbers) (step S140).
Instead of the above, a smoothing process is adopted in which a median filter having a filter window (5 × 1) of m rows and 1 column and a median filter having a filter window (1 × 5) of 1 row and n columns are combined. Therefore, in the following description, different configurations (processing contents) will be described with reference to FIGS.
This will be described in detail with reference to the flowchart of FIG.

In the through hole inspection process in the second embodiment,
As shown in the flowchart of FIG. 13, prior to the smoothing processing by the median filter, the data area to be smoothed is determined, and the coordinate origin (X0, Y0) of the area is obtained (step S200). That is, as shown in FIG. 15, based on the shading-corrected first principal surface gradation data obtained in step 134, or in step S13.
Based on the shading-corrected second principal surface gradation data obtained in 7, a density cross-section graph along the X axis for the through hole region SMe (smoothing process region) of the through hole H is calculated,
Both-end coordinates Xa and Xb along the X-axis are obtained over each row. Further, both-end coordinates Ya and Yb along the Y-axis are obtained for each column from the concentration cross-sectional graph along the Y-axis. Then, the coordinate origin (X0, Y0) is obtained from this result.

In this way, the data area is determined, the coordinate origin (X
After the calculation of (0, Y0), smoothing processing (steps S202 to 252) by the median filter (M / F) is performed on the offset gradation data (320 × 256) of step S139 in the above embodiment. In this smoothing process, first, M / with a filter window of 1 × 5 is used.
The coordinates (Xs, Ys) to be the target of the median filter process (M / F process) by F are determined to be (Xi, Yj) (step S202). Thereby, the M / F process is started from the determined coordinates (Xi, Yj).

After that, the M / F processing coordinates (Xi, Y
data is cut out from the offset gradation data (320 × 256) for the Yj row through-hole row including j) (step S20).
4). In this case, the M / F processing coordinate (Xi, Yj) is (X
0, Y0), the process of step S204
As shown in FIG. 16, the gradation data of the through hole row of the Yj row (X axis) is cut out (320 × 1). In the following description, the first M / F processing coordinate (X
It is assumed that i, Yj) is the coordinate origin (X0, Y0).

Subsequently, M / F processing is performed at (X0, Y0) for the cut-out one row of gradation data (step S206). In this M / F processing, as shown in FIG. 17, the data “3” of the M / F processing coordinates (X0, Y0) is set to 0 in the 1 × 5 M / F filter window so that it is in the center of the filter window. , 3, 3, 4, 2 are stored in this order (FIG. 14A). Next, the data "3" that comes to the center position of the data string in which these data are arranged in the order of size (0, 2, 3, 3, 4) is set as the output value. This output value "3" is output and accumulated at the coordinates (X0, Y0) in the median-filtered data (M / F data).

Next, i is incremented by 1 and M
/ F processing coordinate (Xi, Yj) (= (X0, Y0)) is set to 1
Move to the right by the amount of data (step S208), and check whether there is a sufficient number of data to be stored when M / F processing the coordinates (Xi + 1, Yj) after the movement, specifically, the number of data is 5
It is determined whether or not it is less than (step S210). Here, steps S206 and S208 are repeated until a negative determination is made. That is, at the M / F processing coordinates (X1, Y0) which is moved by one data to the right from (X0, Y0), the data sequence (2) after the rearrangement of 3, 3, 4, 2, 5 stored in the filter window is performed. , 3, 3, 4, 5) output value "3"
(FIG. 17B), the coordinates (X1
, Y0) data. And step S210
Until 5 pieces of data are stored in the filter window in just the right way, that is, as shown in FIG. 17C, 5 pieces of data are stored in the filter window at the right end of the data string. Until then, the M / F process is repeatedly performed on the five data as described above. This figure 1
The output value "2" shown in 7 (c) is the coordinate (Xb- (n-1) / when the filter window of M / F is 1 × n (n is a natural number, n = 5 in this embodiment). 2, Yj) ((Xb-2, Yj) in this embodiment).

Note that the determination in step S210 is 1 ×
When the M / F of n (n is a natural number, n = 5 in this embodiment) is set, the coordinate (Xi + 1, Yj) after the right movement is (Xb-
(n-4), Yj) ((Xb-1, Yj) in this embodiment)
It can be replaced with the judgment of whether or not

On the other hand, in the step S208 after the M / F processing shown in FIG. 17C, if the M / F processing coordinate is moved right by one data, the number of data stored in the filter window becomes four. In the subsequent step S210, a negative determination is made. Therefore, in this case, the right end portion M / F processing described below is performed (step S212).

In this right end M / F processing, an odd number of data smaller than the number of data in the filter window is used. In this embodiment, M is set so that the number of data is three and the number of data is one. While moving the / F processing coordinate (Xi, Yj) to the right, data acquisition, rearrangement, and output value acquisition for three and one data are performed. That is,
As shown in FIG. 17 (d), the data of 2, 1 and 2 are stored in the filter window and rearranged, and the data “2” which comes to the central position of the data string (1, 2, 2)
Is the output value. This output value "2" is used as the data of the coordinates (Xb-1, Y0) in the M / F data. Next, as shown in FIG. 17 (e), one piece of data "2" is taken as an output value as the data coming to the center position. This output value ”
Let 2 ″ be the data of the coordinates (Xb, Y0) in the M / F data. Since it is easy to obtain the data located at the center as described above, it is preferable to perform it on an odd number of data, but an even number of data. For data, for example, (1,
(5,9,8,7,3) are rearranged to form (1, 3, 3,
5, 7, 8, 9) and the data located in the center
Either 5 "or" 7. "Or, if the average value of both is (5 + 7) / 2 = 6, the data located in the center can be obtained.

After step S212, the M / F processing start coordinate (Xi, Yj) is first set to M in order to perform the M / F processing on the data on the left side of the cut-out Yj row through-hole row data column. The filter window of / F is restored (step S214). Then, i is decremented by 1 and the M / F processing coordinate (Xi, Yj) (= (X0,
(Y0)) is moved to the left by one data (step S21)
6). Coordinates (Xi-1, Yj) (= (X-
1, Y0)) is the first processing coordinate when M / F processing is performed on the left side of the data string.

Then, the coordinates (Xi-1, Y
j) (= (X-1, Y0)) as described above and M /
F processing is sequentially performed. That is, following step S216, the M / F process at (X-1, Y0) (step S21
8), the M / F processing coordinate is moved to the left by one data (step S220), the number of stored data at the moved coordinate is determined (step S222) and steps S218 to 220 are repeated, and the left end portion M when the number of data is insufficient / F processing (step S2
24) is performed. Therefore, as shown in FIG. 18, M / F data is accumulated from the coordinates (Xi-1, Yj) to the coordinates (Xa, Yj), and steps S202 to S22 are performed.
By the processes up to 4, M / F data having the same number of data (320 × 1) as the cut-out Yj rows of through holes are created.

M / F for such through-hole rows of Yj rows
Following the processing, as shown in FIG. 11, the same processing is performed for the through-hole rows other than the Yj row, that is, M / F processing start coordinate determination, data cutting, and M for the data on the right side of the start coordinates. / F processing, M / for left data
The F process and these processes for each row are repeated. M for each through-hole row cut out by this
/ F data is created. Therefore, following step S224, 320 × 1 M / F data is collected for all rows to construct M × F data having a size of 320 × 256 (step S226). Hereinafter, the M / F data constructed in step S228 will be referred to as primary M / F data.

Subsequent to the above-described construction of the first-order M / F data, median filtering processing by the M / F having a filter window of 5 × 1 is performed on the constructed first-order M / F data (step S228). ~ 250), secondary M / F data is constructed in step S252. In the M / F processing by this 5 × 1 M / F, the point that the data to be processed is the primary M / F data and the M / F
The above-mentioned M / F has a filter window of 5 × 1
Different from the processing, the data cutting is performed only on the data in the X column, and the M / F processing is different only in that the M / F processing is performed along with the movement of the M / F along the Y axis. Therefore,
A detailed description thereof will be omitted.

The secondary M / F data constructed through the processing with the 5 × 1 M / F in this manner is 320 × 256 in size, and has the same size as the offset gradation data. Then, following step S252, the processes of steps S141 and 142 of FIG. 10 are performed. That is, the offset gradation data is divided by the secondary M / F data to obtain standardized data, and the uneven image based on the standardized data is displayed on the display 52. The display state at this time is the same as that of the uneven image SMG0 described above (see FIG. 12).

In the shadow mask inspection apparatus 30 of the second embodiment, M / F processing is performed with 1 × 5 M / F and 5 × 1 M / F.
Perform with F in two steps. Therefore, according to the shadow mask inspection apparatus 30 of the second embodiment, the calculation speed is improved by reducing the calculation load at the time of M / F processing, and the uneven image display is performed promptly to shorten the inspection time. be able to.

In the shadow mask inspection apparatus 30 of the second embodiment, data acquisition, rearrangement, and output value acquisition for an odd number of data smaller than the number of data in the filter window are performed. Therefore, CCD camera 49
The data number of the raw image captured on the first and second main surfaces is matched with the data number of the secondary M / F data, and the gradation data around the edge of the through hole region SMe of the through hole of the shadow mask SM is obtained. Can be used as it is to obtain M / F data. As a result, according to the shadow mask inspection apparatus 30 of the second embodiment, it is possible to display the unevenness image more clearly by reflecting the data around the edge and to make the unevenness visible, so that it is possible to perform a dramatic visual inspection. It is possible to simplify and improve the inspection accuracy.

Next, another embodiment (third embodiment) will be described. In this third embodiment, the shadow mask S
In capturing M and obtaining the image data Di thereof, the configuration is different in that the shadow mask SM is irradiated with light and the image data Di is obtained from the reflected light. As shown in the block diagram of FIG. 19, the shadow mask inspection apparatus 30A of the third embodiment has two image pickup systems. That is, the shadow mask inspection apparatus 30A uses the CCD on the side of the first main surface S1 of the shadow mask SM as the first imaging system.
It has a camera 49A and a camera control device 62A thereof, and as a second imaging system, a second main surface S2 of the shadow mask SM.
CCD camera 49B and its camera controller 62B on the side of
And has both camera control devices connected to the image processing device 54. The display 52 is the image processing device 5.
4 is the same as in the first embodiment described above.

The optical axes of the CCD cameras of the first and second image pickup systems are arranged so as to be displaced by substantially the length of the shadow mask SM, and the shadow mask SM is movable over each image pickup system. It is supported by a frame body (not shown). First
In the image pickup system of, the half mirror 80 is a CCD camera 49A.
And intersects the optical axis at about 45 degrees, and its reflection surface is diagonally opposed to the shadow mask SM. Then, the light of the light source 81 passes through the diffuser plate 82 and is applied to the half mirror 80, is reflected by the half mirror 80, reaches the first main surface S1 of the shadow mask SM, and further reaches the first main surface S.
The light reflected on the side of 1 is transmitted through the half mirror 80 to C
Reach the CD camera 49A. In this way, the first imaging system obtains the image data Di of the first main surface S1 of the shadow mask SM from the reflected light, and the image data Di
Are used for image processing in the image processing device 54. In addition,
The diffusion plate 82 has a property of diffusing and transmitting light, like the diffusion plate 43 in the above-described embodiment.

The second image pickup system also has a structure similar to that of the first image pickup system described above, and the light emitted from the light source 84 and transmitted through the diffusion plate 85 is reflected by the half mirror 83 and is reflected by the second portion of the shadow mask SM. The CCD camera 4 reaches the main surface S2 and further reflects on the second main surface S2 side and transmits through the half mirror 83.
Reach 9B. In this way, the image data Di for the second main surface S2 of the shadow mask SM is obtained by the second imaging system.
Is obtained from the reflected light, and this image data Di is used for image processing in the image processing device 54.

The first and second image pickup systems are connected to a CCD.
Of course, the shadow mask SM may be sandwiched so that the optical axes of the cameras coincide with each other.

The through hole inspection process of the shadow mask SM by the shadow mask inspection apparatus 30A is performed by the first main surface S1,
The image data Di for the second main surface S2 is executed without inverting the shadow mask SM. That is, in this shadow mask inspection apparatus 30A, the processing shown in FIGS. 7 and 8 is performed similarly to the first and second embodiments, and the first
The image capturing of the first main surface S1 in step S132 in FIG. 10 of the embodiment is performed by the first imaging system described above, and the image capturing of the second main surface S2 in step S135 is performed by the second imaging system described above. Done. In this case, the light source 81 and the light source 84 in the first and second image pickup systems may be constantly turned on. And the first,
After the image is captured by the second image pickup system, the same processing as in the first and second embodiments is performed. When the first and second image pickup systems are arranged so that the optical axes of the CCD cameras coincide with each other as described above, the first and second image pickup systems are arranged before the step S132.
Control of the light source 81 of the second imaging system, the light source 8 of the second imaging system
4 is performed, and prior to step S135, the shadow mask SM is moved to the second imaging system side, the light source 81 is turned off, and the light source 84 is turned on.

Therefore, according to the shadow mask inspection apparatus 30A of the third embodiment, it is not necessary to wait for the inspector to reverse the shadow mask SM as in the first embodiment, and the second main surface S2 can be swiftly set. Since it is possible to obtain data on the inspection, it is possible to improve the inspection efficiency by shortening the inspection time.

The embodiments of the present invention have been described above.
The present invention is not limited to such embodiments, and it goes without saying that the present invention can be carried out in various modes without departing from the scope of the present invention.

For example, the inspection target is not limited to the shadow mask SM, and it goes without saying that the aperture grill or the like can be the inspection target. Also, 1 × 5
The execution order of the M / F of 5 × 1 and the M / F of 5 × 1 can be exchanged. Furthermore, 1x5 M / F and 5x1 M / F
However, the M / F having filter windows of various sizes such as 1 × 7 and 7 × 1 or 1 × 9 and 9 × 1 can also be used. Also, depending on the type of unevenness to be inspected, 1
The size of the next filter window and the size of the secondary filter window may be changed. For example, when mainly examining uneven streaks, 1 × 5 M / F and 7 × 1 M / F are used. Furthermore, it is possible to adopt a configuration in which the size of the filter window is variably set each time according to the required inspection quality and the like. Further, in the above-described embodiment, all the through-hole regions SMe of the through-holes H in the shadow mask SM are imaged and the uneven image is displayed, but the uneven image of only some through-hole regions SMe is displayed. It is also possible to adopt a configuration of displaying, inspecting the surface state of the peripheral wall surface of the through hole in the plate-shaped body having only a single through hole, or displaying an image of the peripheral wall surface.

Further, the data to be smoothed by the median filter is the offset gradation data obtained by dividing the first principal surface gradation data by the second principal surface gradation data, but the invention is not limited to this. , Can also be configured as follows.

First, the first principal surface gradation data and the second principal surface gradation data are separately acquired as described above after the raw images of the respective principal surfaces are acquired, m × n or 1 × n, n × 1. The smoothing process is performed by the median filter of 1 to obtain each of the first smoothed data and the second smoothed data. Next, the first principal surface gradation data is the first smoothing data and the second principal surface gradation data is the second smoothing data.
The first standardized data and the second standardized data are obtained by dividing each by the smoothed data, the first standardized data and the second standardized data are compared, and the first standardized data and the second standardized data are compared. The offset standardized data is obtained by offsetting the data corresponding to. An uneven image is displayed based on this offset standardized data. Even with such a configuration, the peripheral wall surface W of the through hole H
The inspection accuracy of the visual inspection can be improved by providing the uneven image of the unevenness of the light transmittance due to the disturbance of the reflection of light as an image in which the unevenness is more clearly emphasized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating an optical path of transmitted light illumination when transmitting light is imaged from a first main surface side.

FIG. 2 is an explanatory diagram illustrating an optical path of transmitted light illumination when transmitting light is imaged from the second main surface side.

FIG. 3 is an explanatory diagram illustrating an optical path of reflected light illumination when the reflected light is imaged from the first main surface side.

FIG. 4 is an explanatory diagram illustrating an optical path of reflected light illumination when capturing an image of reflected light from the second main surface side.

FIG. 5 is a front view showing an external configuration of a shadow mask inspection apparatus 30 according to the first and second embodiments.

6 is a block diagram showing an electrical configuration of the shadow mask inspection apparatus 30 of FIG.

FIG. 7 is a flowchart showing the entire through hole inspection process performed by the shadow mask inspection apparatus 30.

8 is a flowchart showing the detailed contents of initial setting processing in the inspection processing of FIG.

9 is a schematic diagram schematically showing how an image is displayed on a display 52 by the initial setting process of FIG.

10 is a flowchart showing the detailed contents of input / visualization processing in the inspection processing of FIG.

FIG. 11 is an explanatory diagram schematically illustrating a process performed until offset gradation data is obtained from the first principal surface gradation data and the second principal surface gradation data of the shadow mask SM.

12 is a photograph showing the display state of each uneven image displayed on the display 52 by the inspection process of FIG. 7. FIG.

FIG. 13 is a flowchart showing the first half of the through hole inspection process performed by the shadow mask inspection apparatus 30 of the second embodiment.

FIG. 14 is a flowchart showing the latter half of the through hole inspection processing performed by the shadow mask inspection apparatus 30 of the second embodiment.

FIG. 15 is an explanatory diagram for explaining the processing content of step S200 in this inspection processing.

FIG. 16 is an explanatory diagram for explaining the processing content of step S204 in this inspection processing.

FIG. 17: Steps S206 to 2 in this inspection processing
Explanatory drawing for demonstrating the processing content to 12th.

FIG. 18: Steps S218 to 2 in this inspection processing
Explanatory drawing for demonstrating the processing content to 24.

FIG. 19 is a shadow mask inspection apparatus 30A according to the third embodiment.
FIG. 2 is a block diagram showing the configuration of FIG.

FIG. 20 is a sectional view of a through hole 200 formed by front and back photoetching.

FIG. 21 is a front view of a through hole 200 formed by front and back photo etching.

FIG. 22 is a cross-sectional view of the through hole 200 for explaining how the peripheral wall surface 203 of the through hole 200 is defective.

FIG. 23 is a plan view of the through hole 200 for explaining how the peripheral wall surface 203 of the through hole 200 is defective.

FIG. 24 is an explanatory view showing a sectional end surface of a through hole 200 formed by etching from one main surface.

FIG. 25 is an explanatory diagram for explaining how a conventional through-hole inspection is performed on the shadow mask SM.

[Explanation of symbols]

 30 ... Shadow mask inspecting device 40 ... Optical measuring device 41 ... Surface plate 43 ... Diffusing plate 44 ... Light source 45 ... Mask plate 45a ... Opening 46 ... Stand supporting arm 47 ... Camera holding beam 49 ... CCD camera 50 ... Data processing device 52 ... Display 52a ... Display area 54 ... Image processing device 62 ... Camera control device 64 ... Bus line 66 ... CPU 68 ... Main storage device 70 ... Keyboard 72 ... Auxiliary storage device 74 ... Printer 77 ... Lens part H ... Through hole SM ... Shadow mask S1 ... 1st main surface S2 ... 2nd main surface W ... peripheral wall surface

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[Procedure amendment]

[Submission date] August 25, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 7

[Correction method] Change

[Correction contents]

Claims (9)

[Claims] 1. A method of inspecting a through hole which penetrates a plate-shaped body and has different hole areas on the front and back main surfaces of the plate-shaped body, wherein A first irradiation step of irradiating light required to image the through hole from the first main surface side, and an image of the through hole from the first main surface side irradiated with light in the first irradiation step, and the imaging The first is the light intensity distribution of the image
A first imaging step of obtaining gradation data; a second irradiation step of irradiating with light necessary for imaging a through hole from a second main surface side which is a main surface of the plate-shaped body having a smaller hole area; In the second irradiation step, the through hole is imaged from the side of the second main surface irradiated with light, and the second image is the light amount distribution of the captured image.
A second imaging step of obtaining gradation data, and a third step of comparing the first gradation data and the second gradation data to cancel the data corresponding to the second gradation data from the first gradation data. Inspection of a through hole, which includes: a cancellation step of obtaining gradation data; and a detection step of detecting a surface state of a peripheral wall surface of the through hole in the plate-shaped body based on the third gradation data. Method. 2. The through-hole inspection method according to claim 1, wherein the plate-shaped body is a through-hole plate in which a plurality of through-holes are arranged in a substantially periodic manner, and the first imaging step includes A plurality of through holes in a predetermined range of the through hole plate are imaged from the side of the first main surface, which is irradiated with light in the first irradiation step, and first gradation data which is a light amount distribution of the captured image is obtained. In the second imaging step, a plurality of through holes within a predetermined range of the through hole plate are imaged from the second main surface side where light is irradiated in the second irradiation step, A method of inspecting a through hole, which comprises a step of obtaining second gradation data which is a light quantity distribution of a captured image. 3. The method for inspecting a through hole according to claim 1 or 2, wherein the detecting step displays a peripheral wall surface of the through hole in the plate-shaped body based on the third gradation data. A method for inspecting through holes, characterized in that 4. The method of inspecting a through hole according to claim 2, wherein the detecting step includes a smoothing step of smoothing the third gradation data by a predetermined filter to obtain smoothed data, A method of inspecting a through hole, comprising: a standardization step of dividing three-gradation data by the smoothed data to obtain standardized data; and a display step of displaying an image based on the standardized data. 5. An inspection device for a through hole that penetrates a plate-shaped body and has different hole areas on the front and back main surfaces of the plate-shaped body, the support means supporting the plate-shaped body, and the support means supporting the plate-shaped body. Irradiating light required to image a through hole from the first main surface side, which is the main surface on the side where the hole area is large, of the formed plate, and the light is radiated by the first irradiating means. A first image pickup means for obtaining the first gradation data which is a light amount distribution of the picked-up image by taking an image of the through hole from the side of the first main surface, and the hole area of the plate-like body supported by the support means. The second main surface side, which is the main surface on the smaller side, emits the light required to image the through hole, and the second main surface side from which the light is emitted by the second irradiation means. Second imaging means for imaging the hole to obtain second gradation data which is a light amount distribution of the captured image; and the first gradation data. Offsetting means for comparing the data of the first gradation data and the data corresponding to the second gradation data to obtain third gradation data, and Based on the above, there is provided a detecting means for detecting the surface condition of the peripheral wall surface of the through hole in the plate-like body, and the through hole inspection apparatus. 6. The inspection apparatus for a through hole according to claim 5, wherein the plate-shaped body is a through hole plate in which a plurality of through holes are arranged substantially periodically, and the first imaging unit includes the A means for imaging a plurality of through holes within a predetermined range of the through hole plate from the side of the first main surface irradiated with light by the first irradiation means, and obtaining first gradation data which is a light quantity distribution of the captured image. The second imaging means images a plurality of through holes within a predetermined range of the through hole plate from the second main surface side where the light is irradiated by the second irradiation means, and a light amount of the captured image. An inspection device for a through hole, which is a means for obtaining second gradation data which is a distribution. 7. The through-hole inspection method according to claim 5, wherein the detecting means displays the peripheral wall surface of the through-hole in the plate-shaped body based on the third gradation data. A method for inspecting through holes, characterized in that 8. The through-hole inspection apparatus according to claim 6, wherein the detecting unit smoothes the third gradation data by a predetermined filter to obtain smoothed data, An inspection device for a through hole, comprising: a normalizing means for dividing the 3-gradation data by the smoothed data to obtain standardized data; and a display means for displaying an image based on the standardized data. 9. The through-hole inspection apparatus according to claim 8, wherein the predetermined filter when the smoothing unit performs the smoothing process is a median filter having a filter window of a predetermined size. Characteristic through-hole inspection device.