JP3335503B2 - Inspection method and inspection device for perforated plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a perforated plate in which a large number of perforated plates are arranged at substantially regular intervals to check for irregularities in light transmittance caused by abnormal dimensions of the perforated holes. More particularly, the present invention relates to an inspection method and an inspection apparatus for inspecting a perforated plate such as a shadow mask for a color CRT or a color filter for a liquid crystal display panel.

[0002]

2. Description of the Related Art In general, a shadow mask is manufactured by arranging a large number of through-holes in a thin metal plate in a substantially periodic manner using a photo-etching method. This method of manufacturing a shadow mask corresponds to a coating process in which a resist having etching resistance is applied to the main surface of a thin metal plate to form a resist film on the main surface of the thin metal plate, and corresponds to an electron beam passage hole and the like of the shadow mask. A baking step of irradiating the resist film with light through a pattern plate having a predetermined pattern to bake a predetermined pattern on the resist film, and supplying a developing solution to the resist film having the predetermined pattern printed thereon, A developing step of dissolving and removing a predetermined portion of the film to form a resist film in a predetermined pattern and exposing a main surface of the metal sheet to be etched; and an etching solution for the metal sheet having the resist film formed in the predetermined pattern. Is supplied, and the exposed main surface of the metal sheet not covered with the resist film is etched to form a large number of electron beam passage holes. Consisting of an etching step for forming a through hole.

In the above-mentioned coating process, when the resist is not uniformly applied to the main surface of the metal sheet and the thickness of the resist film formed on the main surface is not uniform, or when the resist film of the metal sheet is etched in the etching step. If the liquid is not supplied uniformly, local dimensional abnormalities occur in many through holes formed in the metal sheet.

[0004] As a method of inspecting the local dimensional abnormality of the through hole, a method of inspecting the unevenness of the light transmittance due to the dimensional abnormality such as the shape and the hole diameter of the through hole has been adopted. More specifically, as shown in FIG. 16, first, the inspector holds the shadow mask SM by hand, and
To a light table 202 having a built-in light source (not shown).
In front of the light-transmitting inclined table surface 204. Then, the light of the light source is applied to the shadow mask SM via the inclined table surface 204, and the shadow mask SM is visually observed while swinging the shadow mask SM as indicated by an arrow in the drawing. At this time, if a dimensional abnormality such as the shape or diameter of the through-hole is locally generated in the shadow mask SM, the inspector recognizes it as unevenness of the light transmittance passing through the through-hole, and this unevenness is within an allowable range. It is determined from the past experience whether or not the shadow mask is a good shadow mask and a defective shadow mask. The unevenness of the light transmittance due to the abnormal size of the through-hole includes the entire unevenness in which the light and shade unevenness is scattered over the entire surface of the shadow mask SM, the partial unevenness in which the light and shade unevenness is partially scattered, the vertical or horizontal direction. There are uneven streaks or the like in which density unevenness occurs linearly in the direction.

[0005]

However, the above-described inspection has the following problems due to the visual judgment of the inspector.

[0006] Even with a good shadow mask, there is unevenness in light transmittance within an allowable range. Moreover, the inspector sees not only the optical unevenness but also the light of the amount corresponding to the light passing through the through hole. Further, in the inspection, the unevenness of the non-defective shadow mask SM is not always compared with the non-uniformity of the shadow mask SM to be inspected. This is performed while visually checking the unevenness of the shadow mask SM to be inspected.
Therefore, a high level of skill and considerable experience was required to determine the quality of the non-defective product and the shadow mask SM to be inspected based on the unevenness of the shadow mask SM. In addition, even if the level of skill and the experience are almost the same, the quality judgment may vary depending on the individual differences of the inspectors and the health condition.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made to simplify visual inspection of light transmittance unevenness caused by abnormal dimensional dimension of a hole in a hole plate of a shadow mask or the like and to improve the inspection accuracy. The purpose is to plan.

[0008]

The procedure adopted in the method for inspecting a perforated plate of the present invention, which has been made to achieve the above object, is based on a perforated plate in which a large number of perforated holes are arranged approximately periodically. In a method for inspecting a perforated plate for inspecting unevenness of light transmittance caused by a dimensional abnormality of a perforated hole, an irradiation step of irradiating light from one main surface side of the perforated plate, An imaging step of imaging from the main surface side to obtain gradation data of the captured image; a smoothing step of smoothing the gradation data by a predetermined filter to obtain smoothed data; Dividing by the smoothed data to calculate normalized data of the captured image; and inspecting the other main surface of the perforated plate to be inspected based on the normalized data. Perforated plate display step and degree of unevenness
Is a non-defective perforated plate within the allowable range, or
As long as the defective perforated plate is in an unacceptable range
Preparing step for preparing the standardized data for a sample
And the limit sample based on the standardized data of the limit sample.
And a limit sample display step of displaying the other main surface .

[0009]

[0010] The present invention has been made to achieve the above object .
The means adopted in the apparatus for inspecting a perforated plate of the present invention is a perforated plate in which a large number of perforated holes are arranged at substantially regular intervals, and the perforated plate for inspecting unevenness in light transmittance caused by a dimensional abnormality of perforated holes. In the plate inspection apparatus, a supporting means for supporting the perforated plate, an irradiating means for irradiating light from one main surface side of the perforated plate supported by the supporting means, and a supporting means supported by the supporting means. An imaging unit that captures the perforated plate from the other main surface side and obtains gradation data of the captured image; a smoothing unit that obtains smoothed data by performing a smoothing process on the gradation data with a predetermined filter; Dividing the gradation data by the smoothed data,
Normalizing means for calculating standardized data of the captured image,
Display means for displaying the other main surface of the perforated plate to be inspected based on the standardized data, and a degree of the unevenness
Is a non-defective perforated plate within the allowable range, or
As long as the defective perforated plate is in an unacceptable range
Storage means for storing the standardized data for the sample
And the display means is provided in addition to the perforated plate to be inspected.
And the standardized data of the limit sample
Means for displaying the other main surface of the limit sample based on
As its gist that this is.

[0011]

In the inspection apparatus of the present invention,
Can be First, the predetermined filter when pre Symbol smoothing means for smoothing processing, m rows and n columns (m, n is a natural number) can and median filter having a filter window of.

[0013] in the second, the previous Symbol smoothing means, m rows and one column (m
Means for obtaining the first smoothed data by smoothing the gradation data with a median filter having a filter window of (natural number), and a median filter having a filter window of 1 row and n columns (n is a natural number). means for determining said smoothed data said first smoothing data smoothed, can and shall to have a.

[0014] Third, the previous Symbol smoothing means, one row and n columns (n
Means for obtaining the second smoothed data by smoothing the gradation data with a median filter having a filter window of (natural number), and a median filter having a filter window of m rows and 1 column (m is a natural number). means for determining said smoothed data said second smoothing data smoothed, can and shall to have a.

[0015] Fourth, the prior SL smoothing means hole plate hole is gradation data of the periphery of the hole area in the range formed of the number of data that do not meet the filter window of the median filter floor The tone data is subjected to smoothing processing using a median filter that uses the data located at the center when the tone data of the number of data that does not satisfy the filter window are arranged in order of the size as output data.

[0016]

[Action] In the inspection method of the hole plate of the present invention that have a above-described configuration, by irradiating light from one main surface of the hole plate in the irradiation step,
Light is passed through the through hole. Thus, light is transmitted from the through-holes of the perforated plate, and a light-dark distribution is obtained on the other main surface side of the perforated plate according to the density of the arrangement of the through-holes. This light / dark distribution is captured as gradation data, which is the density value of a pixel, through imaging of a perforated plate in an imaging step. Noise, which is a high spatial frequency of the gradation data, is reduced through a smoothing process using a predetermined filter in a smoothing process, and smoothed data of a captured image is obtained. Therefore, in this smoothed data, although the distribution of light and dark according to the density of the arrangement of the perforations in the perforated plate is reflected as data, the unevenness of the perforated plate is reduced or reduced as noise or small fluctuation. Removed. Then, in the normalization step, the gradation data is divided by the smoothed data to calculate standardized data of the captured image, and based on the normalized data, the inspection target through-hole plate display step performs An image of the other main surface side of the plate is displayed.

Since the normalized data has undergone the division of the gradation data by the smoothed data, the distribution of brightness and darkness according to the density of the arrangement of the perforations in the perforated plate is removed, and the size of the perforations is abnormal. This is data representing the resulting unevenness of the light transmittance. Therefore, by displaying an image on the other main surface side of the perforated plate based on the standardized data, the unevenness of the light transmittance due to the dimensional abnormality of the perforated hole is emphasized and displayed. (Uneven image).

Further, in the method for inspecting a perforated plate of the present invention , a non-defective perforated plate in which the degree of non-uniformity is acceptable or a degree in which the degree of non-uniformity is not acceptable is obtained in the limit sample display step. An image is displayed based on the standardized data for the limit sample, which is a non-defective perforated plate. Therefore, the inspector can be provided with the non-uniform image of the perforated plate of the limit sample and the non-uniform image of the perforated plate to be inspected in comparison.

Further, in the inspection apparatus for a perforated plate of the present invention, the perforated plate supported by the supporting means is irradiated with light from one main surface of the perforated plate by the irradiating means to pass the light through the perforated hole.
Thus, light is transmitted from the through-holes of the perforated plate, and a light-dark distribution is obtained on the other main surface side of the perforated plate according to the density of the arrangement of the through-holes. This distribution of light and darkness is captured as tone data, which is the density value of a pixel, by capturing an image of the perforated plate by the imaging unit. Noise, which is a high spatial frequency of the gradation data, is reduced through a smoothing process using a predetermined filter included in the smoothing means, and smoothed data of the captured image is obtained. Therefore, in this smoothed data, although the distribution of light and dark according to the density of the arrangement of the perforations in the perforated plate is reflected as data, the unevenness of the perforated plate is reduced or reduced as noise or small fluctuation. Removed. Then, the normalizing means divides the gradation data by the smoothed data to calculate standardized data of the captured image, and based on the normalized data, the display means displays the other main data of the perforated plate to be inspected. The image on the surface side is displayed.

Since the standardized data has undergone the division of the gradation data by the smoothed data, the distribution of lightness and darkness in accordance with the density of the arrangement of the perforations on the perforated plate is removed, and the size of the perforations is abnormal. This is data representing the resulting unevenness of the light transmittance. Therefore, by displaying an image on the other main surface side of the perforated plate based on the standardized data, the unevenness of the light transmittance due to the dimensional abnormality of the perforated hole is emphasized and displayed. (Uneven image).

[0021] In the inspection equipment of the through-hole plate of the present invention,
Non-defective perforated plate in which the degree of unevenness is in an allowable range, or standardized data on a limit sample that is a defective perforated plate in which the degree of unevenness is in an unacceptable range is stored in the storage means, On the basis of the stored standardized data, the display means displays the other main surface of the limit sample and the other main surface of the inspection target perforated plate. Therefore, the inspector can be provided with the non-uniform image of the perforated plate of the limit sample and the non-uniform image of the perforated plate to be inspected in comparison.

[0022] inspection equipment smell of the through-hole plate of this invention
Then , the smoothing processing by the smoothing means is performed by m rows and n columns (m and n are
This is performed by a median filter having a filter window of (natural number). Therefore, from the gradation data, noise is effectively reduced, and smoothed data in which small fluctuations are smoothed is obtained.

[0023] In addition, inspection equipment of the through-hole plate of this invention
, The smoothing means first smoothes the gradation data with a median filter having a filter window of m rows and 1 column (m is a natural number) to obtain first smoothed data. Next, the first smoothed data is smoothed by a median filter having a filter window of one row and n columns (n is a natural number) to obtain smoothed data. For this reason, noise is effectively reduced from the gradation data, and not only is smoothed data in which small fluctuations are smoothed out, but also the smoothing process is performed in two stages.

[0024] In addition, the inspection equipment of the through-hole plate of this invention
In the above, the smoothing means first smoothes the gradation data with a median filter having a filter window of one row and n columns (n is a natural number) to obtain second smoothed data. Next, the second smoothed data is smoothed by a median filter having a filter window of m rows and 1 column (m is a natural number) to obtain smoothed data. For this reason, noise is effectively reduced from the gradation data, and not only is smoothed data in which small fluctuations are smoothed out, but also the smoothing process is performed in two stages.

[0025] In addition, the inspection equipment of the through-hole plate of these present invention
The median filter is used by the smoothing means, and the gradation data is the gradation data around the perforated area, which is the range in which the perforations of the perforated plate are formed, and the number of gradations does not satisfy the filter window of the median filter. Output data is also obtained for data. Therefore, it is possible to match the number of data between the smoothed data and the gradation data and to smooth the gradation data around the perforated area.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of an inspection apparatus for a perforated plate according to the present invention will be described using an inspection apparatus for a shadow mask as an example. First, the external configuration of the shadow mask inspection apparatus 30 of this embodiment will be described. As shown in the front view of FIG. 1, the shadow mask inspection device 30 includes an optical measurement device 40 for imaging the shadow mask SM and obtaining image data, and a data processing device 50 for performing various data processing based on the image data. It is composed of

The optical measuring device 40 has a surface plate 41, and an opening for passing illumination light is formed substantially at the center of the upper surface of the surface plate 41. A glass plate 43 that diffuses and transmits light is placed on the upper surface of the surface plate 41, and a light source 44 is arranged below the glass plate 43. As the light source 44, for example, a high frequency lighting type fluorescent lamp is used. A mask plate 45 (see FIG. 2) is placed on the upper surface of the glass plate 43, and the shadow mask SM is adhered and fixed to the mask plate 45 with an adhesive tape or the like. .

A stand support arm 46 extending upward from the surface plate 41 is provided.
6 is provided with a so-called cantilever camera holding beam 47. The camera holding beam 47 is attached to the stand support arm 46 so as to be adjustable by an adjusting mechanism (not shown).
The camera 49 and the camera 49 can be integrally moved in the vertical direction (Z direction in the figure). The CCD camera 49 is attached to the camera holding beam 47 so as to be adjustable, and can move the CCD camera 49 in the left-right direction (X direction in the figure). For this reason, the CCD camera 49 can be moved up and down, left and right so that the regions to be imaged by the shadow masks of various sizes coincide with the imaging regions of the CCD camera 49.

The CCD camera 49 is a CCD camera in which CCD elements are two-dimensionally arranged, and is capable of digitally outputting a 10-bit digital image in a grayscale range. Note that CC
From the D camera 49, an image of 1,534 pixels × 1,024 pixels can be obtained.

The data processing device 50 includes a display 52 for displaying an image described later, an image processing device 54 for performing various image processing, and a camera control device 62 for controlling the gain and shutter speed of the CCD camera 49. I have.

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 glass plate 43 and the through holes of the shadow mask SM, and enters the CCD camera 49. At this time, the shadow mask SM is
Are adhered and fixed, and a through-hole region SMe, which is a region where the through-hole of the shadow mask SM is formed,
The peripheral region of the shadow mask SM that is exposed from 5a and has no through hole is masked. Therefore, the CCD camera 49 sets the shadow mask SM with respect to the through-hole area SMe.
Is obtained as image data Di of a two-dimensionally arranged gray-scale image (multi-valued image). This image data Di
Is captured by the image processing device 54 via the camera control device 62 and subjected to image processing described later, and then 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 programs registered in advance. The image processing device 54 includes a CPU 66 that performs predetermined other processes in addition to various image processes and the like. Main storage device 68 such as RAM for temporarily storing data such as data Di
And a keyboard 70 for inputting data, an auxiliary storage device 72 for storing data such as image data Di, for example, a flexible disk device, etc., and a printer 74 for outputting inspection results and the like. They are connected to each other via a bus line 64. Further, a camera control device 62 is connected to a bus line 64 of the image processing device 54.
And the display 52 are connected.

Next, a description will be given of a through hole unevenness inspection process performed by the shadow mask inspection apparatus 30 according to the present embodiment with reference to flowcharts shown in FIG.

[0034] The flowchart of FIG. 3, the initial required on shows the outline of beam La inspection process permeable holes of the shadow mask SM performed in this embodiment, the following processing when the processing is started performed (Step S100). For example, the setting (initial setting) of a limit sample shadow mask SM serving as a criterion for judging the quality of unevenness (unevenness of light transmittance due to abnormal size of a through hole) in the main inspection, and the display 52 of the initial screen of the inspection start. Is displayed, and a memory area used in the processing described later is cleared.

When this initialization is performed, the display 52
Displays an initial setting screen, and the input portions of various items (initial setting items) required in the course of the subsequent inspection processing remain without data input on the initial setting screen. Further, in response to 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 non-uniform image of each of the limit sample shadow masks SM is displayed on the display 52 based on the read display image data when necessary items are set in the initial setting described later. In addition, the display image data of the unevenness of the shadow mask SM of each of the limit samples is such that the degree of the unevenness is within a range in which the quality of the shadow mask is allowable and the plurality of shadow masks SM having different degrees of the unevenness are displayed. Are obtained in advance in the same manner as the shadow mask SM to be inspected later for a plurality of shadow masks SM whose quality of the shadow mask is unacceptable and the degree thereof is different, and the auxiliary storage is provided for each shadow mask SM of the limit sample. It is stored in the device 72.

Subsequent to step S100, initial settings are made for various items required in the course of inspection (step S110). In this initial setting, data is sequentially input to the initial setting items on the initial setting screen displayed without inputting data in the initialization processing. That is, as shown in the flowchart of FIG. 4 showing the detailed processing of the initial setting processing, the output file name of the inspection result (step S11
1) The mask type of the mask plate 45 used to mask the shadow mask SM to be inspected (step S11)
2) The name of the inspector (step S113) is sequentially input.
These are displayed in the inspection result displayed or printed out after the inspection is completed. The output file is a file for storing inspection results for each shadow mask SM to be inspected, and has a data format of a sample ID (for example, a manufacturing serial number) of the shadow mask SM to be inspected, an inspector name , Inspection date, etc.

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

The display 52 by this initial setting process
The state of image display on the screen is as shown in the schematic diagram of FIG. That is, the initially set four shadow masks SM
Uneven image SMG1, SMG2, SMG for
3, the SMG 4 and the result input screen RG are displayed on the display area 52a of the display 52 separately at the same time. Since the non-uniform images SMG1 to SMG4 are based on display image data, individual non-uniform images can be individually enlarged and displayed by an enlargement process (not shown) in the image processing device 54. 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 thus displayed limit sample unevenness image S
MG1 to SMG4 are uneven images of the limit sample shadow mask SM initially set in step S100, and differ according to the initial settings. For example, if four shadow masks SM having different levels of overall unevenness in which density unevenness is scattered are set in the initial setting, an unevenness image in which the extent of overall unevenness is gradually changed is displayed. Further, the shadow mask SM of the initial setting is a shadow mask SM having good overall unevenness.
If the shadow mask SM has good partial unevenness, the shadow mask SM has good vertical unevenness, and the shadow mask SM has good horizontal unevenness, uneven images of these different unevennesses are displayed.

Following the initial setting described above, the mask plate 4
It waits for the inspector to complete setting of the shadow mask SM on the glass plate 43 on which 5 is placed, and waits for an input start instruction issued by operating a switch after the setting is completed (step S120). Here, if there is an input start instruction, an input / visualization process of the image of the shadow mask SM is performed (step S130). The lighting of the light source 44 is controlled prior to or simultaneously with the input / visualization processing.

In this input / visualization process, a transmission image of the shadow mask SM to be inspected is captured, and various processes for displaying a non-uniform image are performed. That is, as shown in the flowchart of FIG.
First, the CCD camera 49 adjusts the CCD so as to match the imaging conditions when capturing the transmission image of the shadow mask SM.
The camera 49 is set (Step S131). More specifically, the shutter speed setting and gain setting of the CCD camera 49 are performed based on predetermined imaging conditions such as shutter speed, gain, focus, and the like, and the through-hole area SMe of the through-hole of the shadow mask SM to be inspected. , Focus adjustment, etc., and Z-axis position adjustment of the CCD camera 49 are performed. The Z-axis position adjustment is performed by manually operating an adjustment mechanism (not shown) to vertically move the camera holding beam 47 and the CCD camera 49 with respect to the stand support arm 46, thereby setting the shutter speed and setting the gain. The adjustment and the like are performed by the camera control device 62. Also,
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 to be slightly blurred in order to remove moire that occurs between the arrangement of pixels of the CCD camera 49 and the periodic arrangement of the through holes of the shadow mask SM.

When the imaging conditions of the CCD camera 49 are set in this way, the CCD camera 49 starts imaging of the shadow mask SM on the glass plate 43, and the light emitted from the light source 44 and transmitted through the through holes of the shadow mask SM. A transmission image (hereinafter, referred to as a raw image) is captured by the CCD camera 49 (step S132). The CCD camera 49 outputs the raw image of the shadow mask SM as digital data of 1,534 pixels × 1,024 pixels and a gradation range of 10 bits as gradation data through the camera control device 62 and the bus line 64 via the main storage device 6.
8 is output.

In general, the distance between a large number of through-holes formed in the shadow mask SM is narrow at the center of the shadow mask and widens toward the periphery. 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 gradation data, which is the data of the transmission image of M, is a light-dark pattern (hereinafter, referred to as “bright” at the center of the shadow mask SM and becomes darker toward the peripheral direction, according to the density of the arrangement of the through-holes of the shadow mask SM. This pattern is referred to as grade) is data represented as a shade range.
In addition, the gradation data reflects the shading based on the unevenness of the shadow mask SM.

Then, the gradation data of the raw image is sent to the image processing device 54 via the camera control device 62. In addition to the data output to the image processing device 54, the camera control device 62 displays the raw image on the display 52. Thereby, the imaging area of the CCD camera 49 can be confirmed.

When the gradation data is sent to the image processing device 54 in this way, the image processing device 54 performs image compression on the 4 × 4 pixels of the raw image as a unit (step S 133). Tone data (1,534 pixels x
1,024 pixels × 10 bits; data size is 16 bits = 2 bytes) is compressed to 320 × 256 × 14 bits (data size is the same). By performing this image compression, it is possible to reduce the data processing time when filtering is performed by a median filter described later.

The output signal of the raw image obtained by the CCD camera 49 is superimposed with a signal resulting from uneven light emission distribution caused by the light source 44 and the glass plate 43 itself and uneven sensitivity of the imaging system. Therefore, following the above-described step S133, the compressed image data (grayscale data) is converted into reference data (grayscale data; 32) having the same number of data.
(0 × 256 × 2 bytes) to perform shading correction (step S134). The reference data is gradation data of an image captured in advance with only the mask plate 45 mounted on the glass plate 43 without mounting the shadow mask SM, and is stored in the main storage device 68 in advance. Therefore, this reference data is read at the time of shading correction.

Subsequently, the gradation data after shading correction is converted into 31 pixels × 31 pixels (hereinafter simply referred to as 31 × 31 pixels).
Image correction for smoothing processing by a median filter having a filter window of
135), obtaining median data in which the gradation data is smoothed. In the smoothing process at this time, data (gradation data) that fills each data window of the 31 × 31 filter window is arranged in the order of its size to create a data string, and data at the center position of the data string is created. Processing to be an output value is defined as one processing unit. Then, with respect to the grayscale data compressed to 320 × 256 and subjected to shading correction, while changing the filtering area of the median filter, for example, the filter window is moved one pixel at a time in a predetermined direction, and the above-described processing in one processing unit is performed. This operation is repeated over the data area of the gradation data.

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

Thereafter, the shadow mask SM to be inspected is
The following data conversion is performed to display only the unevenness of the image (step S136). That is, step S133,
At step 134, the grayscale data that has been compressed and subjected to shading correction is divided by the smoothed data that has been subjected to the smoothing processing by the median filter to obtain standardized data for the raw image. In this division operation, if the value of the data of the smoothed data is zero, the division by the corresponding data is not performed, and the corresponding data of the normalized data is set to a value of zero. Since the standardized data obtained in this way has undergone the division of the gradation data by the smoothed data, the grade and large fluctuation of the shadow mask SM reflected as a shade range on the smoothed data are removed, and the size of the through-hole is reduced. This is data representing unevenness in light transmittance due to the abnormality. Note that the normalized data obtained by this division is real number data and is difficult to handle in image processing, so that it is multiplied by a predetermined integer, for example, 4000, to be converted into integer data, to be final normalized data.

Next, an image based on this normalized data,
That is, the unevenness of the light transmittance caused by the dimensional abnormality of the through-hole is displayed on the display 52 (Step S137). As shown in FIG. 7, the unevenness image SMG0 of the shadow mask SM to be inspected obtained by the visualized image display processing is, as shown in FIG.
Display 5 on which G4 and result input screen RG have been displayed
2 is displayed on the screen. That is, the non-uniform image SMG0 and the limit sample non-uniform images SMG1 to SMG4 are divided and displayed simultaneously on the display 52, and these non-uniform images are displayed in comparison. Note that the uneven image SMG in FIG.
Reference numeral 1 denotes a non-uniform image of the limit sample (non-defective product) for the entire non-uniformity, the non-uniform image SMG2 is a non-uniform image of the limit sample (non-defective product) for the horizontal non-uniformity, and the non-uniform image SMG3 is a non-standard sample of the non-standard sample (conforming product) This is a non-uniform image, and the non-uniform image SMG4 is a non-uniform image of a limit sample (non-defective product) for partial non-uniformity. The arrow in the uneven image of the uneven image SMG4 is a mouse cursor.

Here, the contents of processing performed until an uneven image is obtained from a raw image of the shadow mask SM will be schematically described. As shown in FIG. 8, the raw image G captured by the CCD camera 49 is subjected to the processing of steps S132 to 134, and is converted into compressed and shading-corrected gradation data GD. The graph in the figure shows the gradation data GD in the image along the horizontal axis of the raw image. On the other hand, the smoothed data M obtained by smoothing the gradation data GD by the median filter by the processing of step S135
As shown in the figure, / FD is data in which unevenness of the shadow mask SM is reduced or removed from the gradation data GD as noise or small fluctuation, and only the grade of the shadow mask SM is reflected.

Then, after the processing of step S136, normalized data KD obtained by dividing the gradation data GD by the smoothed data M / FD is obtained. In the processing of step S137, the uneven image SMG0 is generated based on the normalized data KD. Is displayed. As shown in the figure, the unevenness image SMG0 is an image of only the unevenness of the shadow mask SM to be inspected, and since the grade has been removed, the unevenness is enhanced.

Step S1 consisting of a series of processes described above
Subsequent to the input / visualization processing of No. 30, an evaluation result input processing is performed as shown in FIG. 3 (step S140). In this processing, the inspector compares the uneven image SMG0 of the shadow mask SM to be inspected displayed by the input / visualization processing with the uneven sample SMG1 to SMG4 of the limit sample, and inputs the result. The input items are the sample ID of the shadow mask SM to be inspected, the evaluation result (discrimination of high quality good, medium quality good, defective, etc.), and the type of unevenness (no unevenness, overall unevenness, partial unevenness, horizontal unevenness, vertical unevenness). There are three items: unevenness and other unevenness) and an unevenness occurrence position (divided position when an uneven image is divided into 4 × 4). It should be noted that the non-uniformity position can be input only when non-uniformity is input in the non-uniformity type, and the input can be skipped when no non-uniformity exists.

When the input of necessary items is completed and the switch for saving data is pressed, these input items are set in step S for the corresponding shadow mask SM to be inspected.
Gradation data compressed by 133 (320 × 256 × 2 bytes)
Is stored in the auxiliary storage device 72 together with the data. Therefore, when it is desired to display a non-uniform image again on the shadow mask SM that has been inspected in this way, it is sufficient to read out this data and perform the processing of step S130 described above. When the data storage is completed, the shadow mask S to be inspected is prepared for the next inspection of the shadow mask SM.
Erasure of the M uneven image SMG0 from the display 52 and erasure of the image data calculated and temporarily stored for displaying the uneven image SMG0 from the main storage device 68 are performed.

Subsequent to the evaluation result input processing in step S140, it is determined whether or not it is necessary to continue the above-described inspection for another shadow mask SM (step S150). If the inspection is to be continued, the above-described processing of steps S120 to S120 is repeated. In addition,
The continuation of the inspection is determined from the pressing state of a predetermined switch.

As described above, in the shadow mask inspection apparatus 30 of this embodiment, the shadow mask SM to be inspected is
The display 52 simultaneously displays a non-uniform image in which only the non-uniformity of the light transmittance caused by the abnormal size of the through hole is emphasized and a non-uniform image in which the non-uniformity of the plurality of limit sample shadow masks SM is emphasized. These uneven images are provided to the inspector. For this reason, the inspector observes only the unevenness with a plurality of limit samples, and observes the shadow mask SM.
Can be determined, and does not require a high degree 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 caused by the abnormal size of the through-hole of the shadow mask SM can be further simplified, and the visual inspection can be performed. Inspection accuracy can be dramatically improved.

In the shadow mask inspection device 30,
Since smoothed data is obtained by performing a smoothing process using a median filter having a 31 × 31 filter window, noise or unevenness as small fluctuation is effectively reduced or eliminated from the grayscale data. For this reason, according to the shadow mask inspection device 30, since the unevenness image is an image in which unevenness is more clearly emphasized, the inspection accuracy of the visual inspection can be further improved.

In the shadow mask inspection device 30,
The evaluation result of the shadow mask SM to be inspected and the compressed gradation data (320 × 256 × 2 bytes) are stored in the auxiliary storage device 72. Therefore, even if the quality of the shadow mask SM needs to be tracked or the like, it can be easily dealt with. More specifically, even if it is later determined that the shadow mask SM is of poor quality, if the uneven image is displayed again using the gradation data at the time of inspection, the indicated poor quality and uneven image are compared. be able to. Therefore, the validity of the evaluation and the cause of the quality defect can be determined.

Here, a modified example of the shadow mask inspection apparatus 30 of the above embodiment will be described. In the above-described shadow mask inspection apparatus 30, the filter window of the median filter is fixed to 31 × 31 for the following reason. However, the filter window can be modified so as to be variably set according to the size of unevenness allowed for the shadow mask SM to be inspected, the type of the shadow mask SM, the size of the image at the time of imaging, the resolution of the display 52, and the like. .

In general, the fluctuation (noise, non-uniformity in the present invention) that can be removed by a low-pass filter such as a median filter that removes a high spatial frequency is about half the size of the filter. Is well known. On the other hand, in a nonuniform image to be displayed, a gradual change exceeding the maximum size allowed for the shadow mask SM is not included in the grade and displayed.
It is desired that a change in size below the maximum size can be displayed as unevenness. In other words, when the gradation data is smoothed by the low-pass filter, the filter size of the low-pass filter allows only the above-described gradual change to pass,
This is a size that blocks fluctuations smaller than this.

Even in the case of a median filter, a filter window having a size that allows only a gradual change to pass and blocks a change smaller than that is required, similarly to a low-pass filter. In the present embodiment, assuming that the variation size (lower limit size) of the shielding variation is about 14 mm and one pixel of the image (320 × 256) displayed on the display 52 is about 0.9 mm, the filter window is calculated according to the following equation. Size F
WS was determined.

FWS / 2 = (14 / 0.9) FWS = (14 / 0.9) × 2 = 31

Therefore, if the size of the pixel and the lower limit size of the shielding fluctuation which influences the level of the inspection quality can be set by, for example, a ten-key pad so as to be set prior to the inspection, a different size can be obtained. Versatility of inspection for unevenness can be improved. Specifically, if one pixel of an image to be displayed is 0.5 mm, from the above equation, the median filter used for the smoothing process is 57 × 5
7 is a median filter having seven filter windows. For this reason, the above embodiment is modified to include a process of determining a filter window of a median filter, and to execute the above step S135 with a median filter having a filter window of a determined size (for example, 57 × 57). Can be.

In addition, the size of the filter window FWS of the median filter can be modified so as to be variably set in consideration of the viewing angle of the lower limit size of the shielding fluctuation.
For example, when the imaging distance of the CCD camera 49 is about 60 cm,
If one pixel of the image (320 × 256) is about 0.9 mm and the viewing angle of the lower limit size of the shielding fluctuation is about 1.3 degree, the following equation is used to shield the size of about 1.3 degree or less. Determine the size FWS of the filter window.

FWS / 2 = (tan (1.3 / 2) × 600 × 2) FWS = (tan (1.3 / 2) × 600 × 2) × 2
= 31

The imaging distance of the CCD camera 49 is about 100c.
m, the filter window size F according to the following equation:
Determine WS.

FWS / 2 = (tan (1.3 / 2) ×
1000 × 2) FWS = (tan (1.3 / 2) × 1000 × 2) ×
2 = 51

That is, the viewing angle of the lower limit size of the shielding fluctuation, the imaging distance of the CCD camera 49, and the like are input prior to the inspection using, for example, a numeric keypad, and the size of the filter window of the median filter can be determined accordingly.
It can also be deformed.

Next, another embodiment (second embodiment) will be described. In the second embodiment, a median filter having an m-row and 1-column filter window (5 × 1) is replaced with a smoothing process (step S135) using a median filter having an m-row and n-column filter window (31 × 31). And a median filter having a 1 × 5 filter window (1 × 5). Therefore, in the following description, different configurations (processing contents) will be described in detail with reference to the flowcharts of FIGS.

In the through hole unevenness inspection processing according to the second embodiment, as shown in the flowchart of FIG. 9, prior to the smoothing processing by the median filter, the data area to be smoothed is determined, and the coordinate origin of the area is determined. X0, Y0) are obtained (step S200). That is, as shown in FIG. 11, based on the image data (gradation data) obtained from the CCD camera 49, a density cross-sectional graph along the X-axis of the through-hole area SMe (smoothing processing area) of the through-hole is obtained. Drawing or calculation is performed, and both end coordinates Xa and Xb along the X axis are obtained over each row. In addition, both end coordinates Ya and Yb along the Y axis are obtained from the concentration cross section graph along the Y axis over each column. From this result, the coordinate origin (X0, Y0)
Ask for.

In this way, the data area is determined and the coordinate origin (X
After the calculation of (0, Y0), the median filter (M / M) is applied to the gradation data (320 × 256) after the shading correction in step S134 in the above embodiment.
F) (steps S202 to S252). In this smoothing process, first, coordinates (Xs, Ys) to be subjected to median filter processing (M / F processing) by M / F having a 1 × 5 filter window are represented by (X
i, Yj) (step S202). As a result, the M / F process performs the determined coordinates (Xi, Yj).
Started from.

Thereafter, the M / F processing coordinates (Xi, Y
Data is extracted from the shading-corrected gradation data (320 × 256) for the Yj through-hole rows including j) (step S204). In this case, the M / F processing coordinates (X
If (i, Yj) is (X0, Y0), step S20
By the processing of No. 4, as shown in FIG. 12, the gradation data of the through-hole row of the Yj-th row (X-axis) is cut out (320 × 1). In the following description, the first M
/ F processing coordinates (Xi, Yj) are coordinate origins (X0, Y0)
It will be described as.

Subsequently, an M / F process is performed on the cut-out one column of gradation data at (X0, Y0) (step S206). In this M / F processing, as shown in FIG. 13, 0 is set in the 1 × 5 M / F filter window so that the data “3” of the M / F processing coordinates (X 0, Y 0) is at the center of the filter window. , 3, 3, 4, and 2 are stored in this order (FIG. 13A). Next, the data "3" at the center of the data sequence in which these data are arranged in the order of their sizes (0, 2, 3, 3, 4) is set as the output value. This output value "3" is output and accumulated at coordinates (X0, Y0) in the median-filtered data (M / F data).

Next, i is incremented by 1 to obtain M
/ F processing coordinates (Xi, Yj) (= (X0, Y0))
The data is moved to the right by data (step S208), and there is no shortage in the number of data to be stored when the M / F processing is performed on the coordinates (Xi + 1, Yj) after the movement.
It is determined whether it is less than (Step S210). Here, steps S206 and S208 are repeated until a negative determination is made. In other words, at the M / F processing coordinates (X1, Y0) moved one data to the right from (X0, Y0), the rearranged data string (2, 3, 4, 2, 5, 5) stored in the filter window , 3,3,4,5) output value "3"
(FIG. 13 (b)) and coordinates (X1) in the M / F data.
, Y0). Then, step S210
13 until the five data are stored in the filter window without excess or shortage, that is, as shown in FIG. 13C, the five data are stored in the filter window at the right end of the data string. Until the above, the M / F processing is repeatedly performed on the five data as described above. This figure 1
The output value “2” shown in 3 (c) is obtained by using coordinates (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).

It should be noted that the judgment in step S210 is 1 ×
Assuming that the M / F is n (n is an odd number, n = 5 in this embodiment), the coordinates (Xi + 1, Yj) after rightward movement are (Xb− (n)
-4), Yj) (in this embodiment, (Xb-1, Yj)).

On the other hand, if the data is shifted right by one data of the M / F processing coordinates in step S208 after the M / F processing shown in FIG. 13C, the number of data stored in the filter window becomes four. In the following step S210, a negative determination is made. Therefore, in this case, the right end M / F processing described below is performed (step S212).

In the right end M / F processing, the odd number of data smaller than the number of data in the filter window. 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 coordinates (Xi, Yj) to the right, data fetching, rearranging, and obtaining output values of three and one data are performed. That is,
As shown in FIG. 13 (d), data of 2, 2 and 1 are stored in the filter window and rearranged, and data "2" at the center of the data sequence (1, 2, 2) is obtained.
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. 13E, one piece of data “2” is set as an output value as data at the center position. This output value "
2 "is the data of the coordinates (Xb, Y0) in the M / F data.

Since data located at the center can be easily obtained as described above, it is preferable to perform the processing on an odd number of data. However, the present invention is not limited to the odd number of data, and may be an even number of data.
For an even number of data, for example, (1, 5, 9,
In the case where six data (8, 7, 3) are data, these six data are rearranged to (1, 3, 5, 7, 8, 9, 9), and the data located at the center thereof is "5". Or "7". Or (5 + 7) / 2, which is the average of the two
If the data located at the center is set to = 6, the data located at the median can be obtained.

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

Subsequently, the coordinates (Xi−1, Y
j) (= (X-1, Y0)) and M /
The F process is sequentially performed. That is, following step S216, the M / F processing at (X-1, Y0) (step S21)
8) Leftward movement of one data of the M / F processing coordinates (step S220), determination of the number of stored data at the coordinates after the movement (step S222) and repetition of steps S218 to S220. / F processing (step S2
24) is performed. Therefore, as shown in FIG. 14, 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 processing up to 4, M / F data of the same data number (320 × 1) as the cut-out Yj through-hole rows is created.

The M / F for the Yj-th row of through-holes
Subsequent to the processing, as shown in FIG. 10, the same processing is performed for the through-hole rows other than the Yj row, that is, determination of the M / F processing start coordinate, data cutout, and M for the data on the right side from the start coordinate. / F processing, M /
The F process and these processes for each row are repeated. Thus, the M for each of the cut-out through-hole rows
/ F data is created. Therefore, following step S224, 320 × 1 M / F data is collected for all rows, and M / F data having a size of 320 × 256 is constructed (step S226). Hereinafter, the M / F data constructed in step S228 will be referred to as primary M / F data.

Subsequent to the construction of the primary M / F data described above, median filter processing by the M / F having a 5 × 1 filter window is performed on the constructed primary M / F data (step S228). To 250), secondary M / F data is constructed in step S252. In the M / F processing by the 5 × 1 M / F, the point that the data to be processed is the primary M / F data and the M / F
The point that the filter window of 5 × 1 is the above M / F
The processing is different from that of the first embodiment only in that data extraction is performed on the data of the X column and the M / F processing is performed along with the movement of the M / F along the Y axis. Therefore, the detailed description is omitted.

The secondary M / F data constructed through the processing by the 5 × 1 M / F is data having a size of 320 × 256, and has the same size as the gradation data of the raw image. Then, following step S252, the processing of steps S136 and 137 in FIG. 6 is performed. That is, the compressed and shading-corrected gradation data is divided by the secondary M / F data to obtain standardized data for the raw image, and an uneven image based on the standardized data is displayed on the display 52. The display at this time is the same as that of the uneven image SMG0 described above (see FIG. 7).

In the shadow mask inspection apparatus 30 of the second embodiment, the M / F processing is performed by the 1 × 5 M / F and the 5 × 1 M / F.
F and 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 in the M / F processing, and the unevenness image is promptly displayed to shorten the inspection time. be able to.

The shadow mask inspection apparatus 30 according to the second embodiment captures, rearranges, and obtains output values of an odd number of data smaller than the number of data in the filter window. Therefore, the CCD camera 49
The number of data of the raw image picked up in step 2 is matched with the number of data of the secondary M / F data, and the M / F data is converted using the gradation data around the edge of the hole area SMe of the hole of the shadow mask SM as it is. Obtainable. As a result, the second
According to the shadow mask inspection apparatus 30 of the embodiment, the unevenness image can be displayed more clearly through reflection of the raw data around the edge and the unevenness can be made obvious, thereby dramatically simplifying the visual inspection and inspecting. The accuracy can be improved.

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

For example, in place of the smoothing processing by the median filter, a smoothing processing by a moving average method or a quartic approximation method can be adopted. In these smoothing processes, FIG.
As shown in FIG. 5, a window is applied to the shadow mask SM, and the density (gradation data) of the image in the window is integrated to obtain an average value Rav. Then, it is smoothed to obtain a grade through density integration, moving average of average data or four-dimensional approximation by the least square method. After that, the density integrated data is divided by this grade data to standardize the data, and an uneven image is displayed.

Further, the size of the primary filter window and the size of the secondary filter window may be changed according to the type of unevenness to be inspected. For example, when mainly inspecting uneven streaks, a 1 × 5 M / F and a 7 × 1 M / F are used. Still further, a configuration may be adopted in which the size of the filter window is variably set each time according to the required inspection quality or the like.

[0089]

As described above in detail, in the method for inspecting a perforated plate according to the present invention , unevenness in light transmittance caused by anomalous dimensions of perforated holes in the perforated plate is emphasized and displayed and provided to the inspector. I do.
For this reason, the inspector only has to visually judge the quality of the perforated plate to be inspected, in which the unevenness is emphasized, and does not require a high level of skill or considerable experience. Therefore, it is possible to simplify the visual inspection of the unevenness of the light transmittance caused by the dimensional abnormality of the aperture of the aperture plate, and to improve the inspection accuracy of the visual inspection . In addition, the inspector is required to provide a sample plate
And compare the uneven images of the perforated plate to be inspected
Visual inspection, which simplifies visual inspection and improves inspection accuracy.
It can be further improved.

[0090]

In the inspection apparatus for a perforated plate according to the present invention, unevenness in light transmittance caused by an abnormal dimensional dimension of the perforated plate in the perforated plate is emphasized and displayed, and provided to the inspector. For this reason, the inspector only has to visually judge the quality of the perforated plate to be inspected, in which the unevenness is emphasized, and does not require a high level of skill or considerable experience. Therefore, it is possible to simplify the visual inspection of the unevenness of the light transmittance caused by the dimensional abnormality of the aperture of the aperture plate, and to improve the inspection accuracy of the visual inspection . In addition, the inspector gives the limit sample perforated plate and the inspection target
Visually compare the uneven image with the perforated plate
Simplifies visual inspection and improves inspection accuracy
Can be made.

[0092]

[0093] In the testing apparatus of the present invention, through the smoothing processing by the median filter having a filter window of m rows and n columns, and effective noise reduction of the gradation data, the smoothing of small variations in FIG Rukoto . Like this
For example, an image in which unevenness in light transmittance is further enhanced can be obtained, so that the inspection accuracy of the visual inspection can be further improved.

[0094] Also, it performed separately smoothing process by the median filter in two stages, was Rukoto reduce operation load of each smoothing. This can improve the smoothing processing speed and shorten the inspection time.

[0095] Further, it performed separately smoothing process by the median filter in two stages, was Rukoto reduce operation load of each smoothing. This can improve the smoothing processing speed and shorten the inspection time.

[0096] Further, to the number of data matching between the smoothed data and tone data, the smoothing processing of the gradation data in the vicinity of the hole region of the hole plate to FIG Rukoto. In this way, when dividing the gradation data by the smoothed data, it is not necessary to align the gradation data and the smoothed data on the perforated plate, so that the division processing speed can be reduced and the perforated area can be reduced. An uneven image in the periphery can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing an external configuration of a shadow mask inspection apparatus 30 according to an embodiment.

FIG. 2 is a block diagram showing an electrical configuration of the shadow mask inspection device 30.

FIG. 3 is a flowchart showing the entirety of a through hole unevenness inspection process performed by a shadow mask inspection apparatus 30;

FIG. 4 is a flowchart showing detailed contents of an initial setting process in the unevenness inspection process.

FIG. 5 is a schematic diagram schematically showing an image displayed on a display 52 by the initial setting process.

FIG. 6 is a flowchart showing detailed contents of an input / visualization process in the unevenness inspection process.

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

FIG. 8 is an explanatory diagram schematically illustrating the contents of processing performed until a non-uniform image is obtained from a raw image of a shadow mask SM.

FIG. 9 is a flowchart showing the first half of a through hole unevenness inspection process performed by the shadow mask inspection apparatus 30 of the second embodiment.

FIG. 10 is a flowchart showing the latter half.

FIG. 11 shows a step S200 in the unevenness inspection processing.
FIG. 4 is an explanatory diagram for describing the processing content of FIG.

FIG. 12 is a step S204 in the unevenness inspection processing.
FIG. 4 is an explanatory diagram for describing the processing content of FIG.

FIG. 13 is a step S206 in the unevenness inspection processing.
FIG. 4 is an explanatory diagram for describing processing contents of to 212.

FIG. 14 is a step S218 in the unevenness inspection process.
FIG. 9 is an explanatory diagram for describing processing contents of to 224.

FIG. 15 is an explanatory diagram illustrating an outline of a smoothing process using a moving average method or a quartic approximation method that replaces the smoothing process using a median filter.

FIG. 16 is an explanatory diagram for explaining a state of a conventional unevenness inspection for a shadow mask SM.

[Explanation of symbols]

REFERENCE SIGNS LIST 30 shadow mask inspection device 40 optical measurement device 41 platen 43 glass plate 44 light source 45 mask plate 45 a opening 46 stand support 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 unit SM Shadow mask

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tohru Shibahara 480-1, Takamiya-cho, Hikone City, Shiga Prefecture Dainippon Screen Manufacturing Co., Ltd. Hikone District Office (72) Inventor Yoshiharu Asai 480 Takamiyacho, Hikone City, Shiga Prefecture No. 1 Dainippon Screen Manufacturing Co., Ltd., in the Hikone area office (72) Inventor Masakuni Ito 480 Takamiya-cho, Hikone City, Shiga Prefecture No. 1 Dainippon Screen Manufacturing, Ltd. in the Hikone area office (56) References JP-A-2-93313 (JP, A) JP-A-7-103912 (JP, A) JP-A-59-159005 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11 / 30 G01N 21/88 G06T 7/00

Claims (6)

(57) [Claims] 1. A method of inspecting a perforated plate having a large number of perforated holes arranged in a substantially periodic manner, wherein the perforated plate is inspected for unevenness in light transmittance caused by a dimensional abnormality of the perforated holes. An irradiating step of irradiating light from one of the main surfaces; an imaging step of imaging the perforated plate from the other main surface side to obtain gradation data of the picked-up image; A smoothing process of obtaining smoothed data by performing a smoothing process using a filter; a normalizing process of dividing the gradation data by the smoothed data to calculate standardized data of the captured image; based on the inspection hole plate display step of displaying the other main surface of the through hole plate to be inspected, through hole plate of non-defective range of the degree of the unevenness is permitted,
Or a defective product whose degree of unevenness is in an unacceptable range
Based on the standardized data for the limit sample that is a perforated plate
Before the limit sample, based on the preparation process to be prepared and the standardized data of the limit sample,
And a limit sample display step of displaying the other main surface . 2. A perforated plate inspection apparatus for inspecting non-uniformity of light transmittance due to a dimensional abnormality of a perforated plate, wherein the perforated plate has a large number of through holes arranged substantially periodically. A radiating means for irradiating light from one main surface side of the perforated plate supported by the supporting means, and an image of the perforated plate supported by the supporting means from the other main surface side An imaging unit that obtains grayscale data of the captured image; a smoothing unit that obtains smoothed data by performing a smoothing process on the grayscale data using a predetermined filter; division to a standardization means for calculating a normalized data of the captured image, on the basis of the normalized data, and display means for displaying the other main surface of the through hole plate to be inspected, the unevenness Good quality perforated plate whose degree is in the acceptable range,
Or a defective product whose degree of unevenness is in an unacceptable range
Record the above standardized data for the limit sample which is a perforated plate.
Storage means for storing the other main surface of the perforated plate to be inspected.
Display and based on the standardized data of the limit sample
Means to display the other major surface of the limit sample.
And a perforated plate inspection apparatus. 3. The inspection apparatus for a perforated plate according to claim 2, wherein the predetermined filter when the smoothing unit performs the smoothing process is a filter of m rows and n columns (m and n are natural numbers). An inspection device for a perforated plate, which is a median filter having a window. 4. The inspection apparatus for a perforated plate according to claim 2 , wherein the smoothing means smoothes the gradation data with a median filter having a filter window of m rows and 1 column (m is a natural number). Means for processing to obtain first smoothed data; means for obtaining the smoothed data by smoothing the first smoothed data with a median filter having a filter window of one row and n columns (n is a natural number) And an inspection apparatus for a perforated plate. 5. The inspection apparatus for a perforated plate according to claim 2 , wherein the smoothing means smoothes the gradation data with a median filter having a filter window of one row and n columns (n is a natural number). Means for processing to obtain second smoothed data; means for obtaining the smoothed data by smoothing the second smoothed data with a median filter having a filter window of m rows and 1 column (m is a natural number) An inspection device for a perforated plate, comprising: 6. The inspection apparatus for a perforated plate according to claim 3 , wherein the smoothing means is a floor around a perforated region in which the perforated plate is formed. For tone data that is tone data and does not satisfy the filter window of the median filter, when the tone data of the number of data that does not satisfy the filter window are arranged in order of their size, the data that comes to the center is output data. An inspection apparatus for a perforated plate which performs a smoothing process using a median filter.