JP2004245829A - Apparatus for inspecting pattern defect, and method of inspecting pattern defect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of inspecting pattern defects which automatically detects coating defects in fluorescent material coated on a glass substrate of a plasma display or the like, without being influenced by a coating pattern, such as a lattice-like fluorescent coating film, is easily installed in a production line of a panel, and realizes low-priced and high-speed defect inspection. <P>SOLUTION: The method comprises taking an image of the pattern of the lattice-like phosphor coated film formed on the substrate, calculating the lattice pitch of the lattice-like fluorescent coating film from an image signal obtained by the image, comparing image data of at least two regions the size of an integral multiple of the lattice pitch from the image signal, and detecting pattern defects in the lattice-like fluorescent coating film, based on the result of comparison. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a pattern defect inspection apparatus and a pattern defect inspection method, and more particularly to a pattern defect inspection apparatus and a pattern defect inspection method for automatically inspecting a coating defect of a phosphor applied to a glass substrate such as a plasma display. is there.

  2. Description of the Related Art There is a conventionally known pattern defect inspection apparatus for inspecting coating or printing defects of a phosphor applied or printed on a glass substrate such as a plasma display. In this apparatus, for example, a glass substrate such as a plasma display in which phosphors are formed in a stripe shape is irradiated with ultraviolet rays from an ultraviolet light source to cause the formed phosphors to emit light. This light-emitting image is captured by an imaging unit such as a line sensor (one-dimensional sensor). Since the formed phosphors are red (R), green (G), and blue (B) phosphors, when an image is taken by the imaging unit, the color corresponding to each of the R, G, and B phosphors is used. The filter is mounted on the imaging unit, and configured to capture an image corresponding to each phosphor. The image picked up by the image pickup unit is output to an image processing unit, and for example, there is a device for inspecting a pattern defect of a phosphor stripe applied to a glass substrate by displaying the image on a display device or the like. Since the coating defect of the phosphor is detected from the luminance signal level, a highly accurate inspection cannot be performed.

  In addition, the patent application 2002-280694 (filed on Sep. 26, 2002) previously filed by the present inventor includes a pattern defect inspection apparatus and a pattern defect inspection method for inspecting a coating defect of a phosphor using a difference image. There is a way. This will be described with reference to FIG. FIG. 5 is a diagram for explaining the principle of detecting a pattern defect such as a pinhole in the pattern defect inspection apparatus. FIG. 5 shows a case where phosphor stripes 51 of R, G and B colors are periodically applied on a glass substrate 50 such as a plasma display.

  Image data captured by the imaging unit is sent to the image processing unit, where the image data is processed. The image processing unit divides the image data into a plurality of blocks. For example, a well-known block of 4 × 4 pixels (hereinafter, referred to as a 4 × 4 block or the like), an 8 × 8 block, or a 32 × 32 block 52 and 53 is cut out, and a difference image detecting unit is cut out. It is output to 54. In the difference image detection unit 54, the luminance signal levels of the pixels of the block 52 and the block 53 are compared.

  When a defect 55 such as a pinhole is on the phosphor stripe 51 (FIG. 5 shows a case where the R phosphor stripe has the defect 55), the defect 57 is detected as a difference in the luminance signal level in the difference image 56. You. The output of the difference image detection unit 54 is compared with a predetermined judgment level (threshold) by a defect detection unit, and if the difference image exceeds the judgment level, it is detected as a defect. The difference image 56 is directly displayed on the display unit, or a signal of the binarized image 58 and the binarized defect 59 is obtained, so that the defect can be automatically detected.

  However, in the above-described method, when the phosphor stripes 51 of R, G, and B colors are periodically applied on the glass substrate 50, the coating defect of the phosphor can be detected with extremely high accuracy. If the phosphor stripe applied on the glass substrate 50 is not a uniform stripe structure as shown in FIG. 5, there is a problem that this method cannot be applied.

  FIG. 6 is a view for explaining the principle of detecting a pattern defect such as a pinhole in a pattern defect inspection apparatus for explaining the problem. 6, the same components as those in FIG. 5 are denoted by the same reference numerals. Reference numeral 60 denotes a phosphor coating film applied on the glass substrate 50, which is formed in a lattice shape. That is, red (R), green (G), and blue (B) phosphors are periodically and repeatedly applied in the lateral direction. The vertical direction is separated by a gap 61 and is separated into an island shape. Hereinafter, such a phosphor coating film is referred to as a grid-like phosphor coating film.

  A case where a pattern defect such as a pinhole of the lattice-shaped phosphor coating film having such a structure is inspected by the above-described inspection method of the phosphor coating defect using the difference image will be described below. As in FIG. 5, the difference image detection unit 54 compares the luminance signal levels of the pixels of the blocks 52 and 53 with each other. When the defect 55 such as a pinhole is on the lattice-shaped phosphor coating film 60 (in FIG. 5, the case where the defect 55 is present in the R lattice-shaped phosphor coating film 60), the defect 57 is included in the difference image 56 with luminance. Detected as a difference in signal level.

  On the other hand, in the difference image 56, the difference image of the gap 61 is also detected as 62. That is, since the position of the gap 61 is different between the block 52 and the block 53 as is apparent when comparing the pixels of the block 52 and the block 53, the defect 57 and the gap 61 are included in the difference image 56 output from the difference image detector 54. The difference image 62 of the defect 57 and the difference image 62 of the gap 61 cannot be distinguished. Therefore, the binarized image 58 also has a signal of the binarized defect 59 and the binarized image 63 of the gap, so that the defect 59 cannot be automatically detected.

  In consideration of the apparent position data, it can be considered that it is possible to determine whether it is the phosphor coating defect portion 59 or the gap portion. However, it is possible to determine whether the fluorescent material is actually coated on a glass substrate such as a plasma display. Since the width of the body coating film 60 is 200 μm to 250 μm, and the width of the gap is about 100 μm, which is an extremely fine phosphor screen, detection from position information is impossible.

  As a defect inspection of a pattern such as a fine electrode, an adjacent comparison inspection method (for example, see Patent Document 1) is known. This is to detect a fine pattern defect such as an electrode of a plasma display. The method is known in which a plurality of electrodes are grouped, one of the electrodes in the group is compared with one of the electrodes in another group, and this is repeated to inspect all the electrodes for defects. ing. However, according to this adjacent comparison inspection method, in order to compare electrodes between groups, it is necessary to perform alignment with high accuracy. However, as described above, the grid-like phosphor coating film of the plasma display is However, since the alignment is extremely fine, it is necessary to consider the shape of the pattern and the like in order to perform the alignment, and in order to perform the alignment accurately, an extremely high-precision alignment device is required. It is difficult to realize a low-cost defect inspection apparatus.

JP-A-2000-55817 (pages 2, 3; FIG. 1)

  An object of the present invention is to provide a pattern defect inspection apparatus and a pattern defect inspection method for automatically detecting a coating defect of a phosphor applied to a glass substrate such as a plasma display.

  It is another object of the present invention to provide a pattern defect inspection apparatus and a pattern defect inspection method for inspecting pattern defects with high sensitivity without being affected by a phosphor coating pattern such as a grid-like phosphor coating film.

  Still another object of the present invention is to provide a pattern defect inspection apparatus and a pattern defect inspection method which can be easily installed on a production line of a display panel such as a plasma display and which can realize high-speed defect inspection and low cost. .

  The pattern defect inspection apparatus of the present invention includes an imaging unit that images a pattern of a grid-like phosphor coating film formed on a substrate, a moving mechanism unit that moves the imaging unit along the pattern, An image processing unit to which the video signal is input, a display unit that displays an output of the image processing unit, and a control unit that controls the moving mechanism unit and the image processing unit. A grid pitch calculating unit for calculating a grid pitch of the pattern of the phosphor-like coating film, a comparing unit for comparing image data of at least two regions having a size of an integral multiple of the grid pitch, and the pattern of the pattern based on the comparison result. And a defect detection unit for detecting a defect.

  Further, in the pattern defect inspection apparatus according to the present invention, the image pickup unit includes a plurality of line sensor cameras arranged linearly, and each line sensor camera is arranged such that its field of view partially overlaps. The moving mechanism has a function of moving the plurality of line sensor cameras arranged linearly at a constant speed in a direction perpendicular to the arrangement direction of the cameras.

  Further, in the pattern defect inspection apparatus of the present invention, the two image data are image data from two adjacent block areas of the pattern of the lattice-shaped phosphor coating film, and the comparing unit is configured to output the two image data. It is configured to output a difference image of the image data obtained from the block area.

  Further, in the pattern defect inspection method according to the present invention, the step of imaging the pattern of the grid-like phosphor coating film formed on the substrate, the grid pitch of the pattern of the grid-like phosphor coating film from the image data obtained by the imaging. , A step of comparing image data of at least two areas having an integral multiple of the lattice pitch from the image data, and a step of detecting a defect of the pattern based on the comparison result.

  In the pattern defect inspection method according to the present invention, the step of comparing the image data of at least two regions having an integral multiple of the lattice pitch from the image data includes the step of adjoining the pattern of the lattice-shaped phosphor coating film. Selecting two block areas and detecting a difference image of image data obtained from the two block areas, moving the entire pattern while maintaining the relevance of the two block areas, Is configured to detect the difference image of.

  In the pattern defect inspection method according to the present invention, the step of calculating the grid pitch of the pattern of the grid-like phosphor coating film from the image data obtained by the imaging includes the step of: Is the step of detecting

  Furthermore, in the pattern defect inspection method of the present invention, the substrate is a glass substrate of a plasma display, and the above steps are repeated for each manufacturing process of forming the grid-like phosphor coating film on the glass substrate. .

  As described above, the present invention can automatically detect coating or printing defects of phosphors coated or printed with phosphors of each color of R, G, and B on a glass substrate such as a plasma display, and In addition, pattern defects can be inspected with high sensitivity without being affected by the pattern of the lattice-shaped phosphor coating film. In addition, since pattern inspection of fine patterns such as plasma displays can be performed automatically, it can be easily installed on the production line of display panels such as plasma displays, and is a high-speed and low-cost pattern inspection system. And a pattern defect inspection method can be realized.

  FIG. 1 is a diagram showing an embodiment of the pattern defect inspection apparatus of the present invention. In FIG. 1, 1 is a mounting table for a glass substrate such as a plasma display, etc., 2 is a glass substrate such as a plasma display, 3 is an R, G, B lattice phosphor coating film, and 4 is a lattice phosphor. A light source for ultraviolet illumination for causing the coating film 3 to emit light, 5 is an optical system in which a lens and R, G, B color filters are sequentially mounted, 6 is an imaging unit such as a line sensor camera for imaging, and 7 is an imaging unit. A moving mechanism for scanning the imaging unit 6 and the light source 4 on the glass substrate 2 along the glass substrate 2, an image processing unit 8 for detecting a defect such as a pinhole, and a display or printing of an inspection result 9 A display unit such as a color monitor, a printer, etc., a drive unit 10 for driving the moving mechanism unit 7, a control unit 11 for controlling the image processing unit and the drive unit, and an operation unit 15; This is the part that operates the inspection deviceThe image processing unit 8 includes an image input unit 12, a difference image detection unit 13, and a defect detection unit 14, as described later. The ultraviolet light source 4 is not limited to an ultraviolet light source as long as it emits light from the phosphor coating film, and may be a particle beam such as a gamma ray or an X-ray in addition to an electromagnetic wave.

  FIG. 2 is an enlarged view of a mounting table, a glass substrate, and an imaging unit of the pattern defect inspection apparatus shown in FIG. 1, and the same components as those in FIG. 1 are denoted by the same reference numerals. The mounting table 1 is a table on which the glass substrate 2 is mounted at the time of inspection. When, for example, a red (R) phosphor coating film is applied to the glass substrate of the plasma display panel, the application state is inspected. For this purpose, a glass substrate coated with a red (R) phosphor coating film is transported from the direction indicated by the arrow, is fixed at a predetermined position shown in FIG. 2, and is inspected for defects. The same inspection is performed on the line for applying the green (G) phosphor coating film and the line for applying the blue (B) phosphor coating film. In this embodiment, the size of the glass substrate is 1460 mm × 1030 mm, but is not limited to this.

  Reference numeral 21 denotes a part of the moving mechanism 7, which is a support member for supporting the imaging unit 6 and the ultraviolet light source 4. The imaging unit 6 is configured so that four line sensor cameras are arranged in a row as shown in the figure for inspection of one glass substrate, and cover a glass substrate having a width of 1030 mm. The imaging width of one line sensor camera is about 260 mm, and the visual field range between the line sensor cameras is configured to partially overlap. Ultraviolet rays 22 from the ultraviolet light source 4 are reflected by the glass substrate 2, and an image of the red (R) phosphor coating film 3 is taken by the imaging unit 6 via the optical system 5. The support member 21 moves from the right end to the left end of the red (R) phosphor coating film 3 at a constant speed in the Y direction, and scans the entire glass substrate.

  Hereinafter, this operation will be described in detail. A glass substrate 2 such as a plasma display is irradiated with ultraviolet rays 22 from an ultraviolet light source 4 to emit light from the applied phosphor coating film 3 (including printing). The light emission image is captured by the imaging unit 6. At this time, a color filter corresponding to each color phosphor is attached to the imaging unit 6 according to the type (R, G, B) of the phosphor to be detected. The image captured by the imaging unit 6 is sent to the image processing unit 8.

  FIG. 3 is a view for explaining the principle of detecting a pattern defect such as a pinhole in the pattern defect inspection apparatus of the present invention. 3, the same components as those in FIG. 6 are denoted by the same reference numerals. In FIG. 3, a phosphor coating film 60 is applied on a glass substrate 50 to form a lattice. That is, red (R), green (G), and blue (B) phosphors are periodically and repeatedly applied in the lateral direction. In the vertical direction, red (R), green (G), and blue (B) phosphors are separated by gaps 61 and separated into islands. Hereinafter, such a phosphor coating film is referred to as a grid-like phosphor coating film. In the following description, a glass substrate on which the phosphor coating films 60 of R, G, and B are all applied will be described. However, in an actual manufacturing line, the phosphor coating of each color is applied as described above. Of course, each time the film 60 is applied in sequence, it is inspected, and when a defect is detected, the next phosphor coating or printing process is stopped, the defective glass substrate is washed, It is better to newly apply or print the phosphor again in that the application or printing is not wasted. For this purpose, it is necessary to carry out inspection in accordance with the tact time of the production line. Therefore, a pattern defect inspection apparatus having a high inspection speed is required.

  Thus, the image data captured by the imaging unit 6 is sent to the image processing unit 8 and input to the image input unit 12. The image input unit 12 divides the image data into a plurality of blocks. Next, the blocks 31 and 32 are cut out and output to the difference image detection unit 13. The relationship between the size of the blocks 31 and 32 and the lattice-shaped phosphor coating film 60 will be described later.

  The difference image detector 13 compares the block 31 with the block 32. As a comparison method, for example, the difference image detection 54 between the blocks 31 and 32 is performed by comparing the luminance signal levels of the respective pixels of the blocks 31 and 32. When a defect 55 such as a pinhole is present on the phosphor coating film 60 (FIG. 3 shows a case where the R phosphor coating film has the defect 55), the defect 57 appears as a difference in the luminance signal level in the difference image 56. Is detected. The output of the difference image detection unit 13 is compared with a predetermined judgment level (threshold) by the defect detection unit 14 and if the difference image exceeds the judgment level, it is detected as a defect. Since the difference image 56 is directly displayed on the display unit 9 or a signal of the binarized image 58 and the binarized defect 59 is obtained, the defect can be automatically detected. Note that, as is apparent from FIG. 3, the difference image 62 of the gap 61 described in FIG. 6 has been removed. Hereinafter, this principle will be described with reference to FIG.

  FIG. 4 is a diagram for explaining the principle of the present invention, and shows the relationship between the lattice-shaped phosphor coating film 60 and the block 41 for cutting out an image. The block 41 is a block for cutting out an image in order to measure the lattice pitch of the lattice-shaped phosphor coating film 60. The blocks 31 and 32 are not necessarily the same, but have the same size. You can also set it. First, in order to measure the lattice pitch of the lattice-like phosphor coating film 60, the substrate on which the lattice-like phosphor is applied first is photographed, and the block 41 is cut out from the image captured by the image input unit. Next, the pitch between the vertical pixels and the horizontal pixels of the pattern of the grid-like phosphor coating film 60 is determined.

  For example, in FIG. 4, the pitch is determined by calculating the sum of the luminance levels of the pixels in the vertical and horizontal directions of the luminance level of the R phosphor. Although the description has been given of the R phosphor here, the phosphors of G and B have the same pitch, and the description thereof will not be repeated. The sum of the luminance levels of the pixels is used because the luminance level of one pixel is a small luminance level, so that a somewhat larger level enables more accurate pitch measurement.

In FIG. 4, reference numeral 42 denotes an added value of luminance levels of pixels in the vertical direction, and reference numeral 43 denotes a predetermined threshold. The threshold value is set in advance by an experiment so that the pitch can be accurately obtained, for example, 70% of the luminance level 42. Therefore, a pitch between pixels is detected for a luminance level exceeding the threshold value 43, and then an average value Px is obtained. That is,
Px = (Px1 + Px2 +... + Pxn) / n (1)
Here, n is a positive integer.
Similarly, 44 is the sum of the luminance levels of the pixels in the horizontal direction, and 45 is a predetermined threshold. Therefore, the pitch between pixels is detected for a luminance level exceeding the threshold value 45, and then the average value Py is obtained. That is,
Py = (Py1 + Py2 +... + Pym) / m (2)
Here, m is a positive integer.

  Thus, the average pitches Px and Py in the vertical and horizontal directions are obtained. The sizes of the blocks 31 and 32 are determined based on the average pitches Px and Py. That is, among the sizes of the blocks 31 and 32, at least the size in the arrangement direction of the blocks 31 and 32 is set to an integral multiple of the average pitch in the direction. In the example of FIG. 3, the blocks 31 and 32 are arranged in a vertical positional relationship, and the arrangement direction of the blocks is the vertical direction. Therefore, the size of the blocks in the vertical direction (Y direction) is Py. Set to an integer multiple. The blocks may be arranged in the horizontal direction. In this case, the size of the block in the horizontal direction (X direction) is set to an integral multiple of Px.

  The blocks 31 and 32 are set to the same size to detect a difference image. The blocks 31 and 32 are sequentially moved, and the difference image is detected for the entire glass substrate, whereby the lattice-shaped phosphor is detected. All defects of the coating film 60 can be inspected. In addition, by storing these inspection data in a storage unit (not shown) and analyzing the inspection data, it is also possible to make use of quality control in manufacturing. Further, although the comparison based on the luminance signal level has been described as the comparison method, it is needless to say that the present invention is not limited to this, and the difference image can be detected by comparison using a histogram of image signals.

  Another embodiment of the present invention will be described with reference to FIG. Note that the same components as those in FIG. 3 are denoted by the same reference numerals. In the embodiment shown in FIG. 7, the longitudinal direction of the lattice-shaped phosphor coating film 60 shows a case where the coating is performed on the glass substrate 50 in the horizontal direction. In the example of FIG. 7, the positional relationship between the block areas 71 and 72 for detecting the difference image is arranged in a positional relationship where the horizontal direction is the arrangement direction. In such a positional relationship, at least the size of the block area in the horizontal direction (X direction) that is the same as the arrangement direction is set to an integral multiple of the average pitch. Then, the positional relationship between the grid-like phosphor coating films 60 of the respective colors in the block region 71 and the positional relationship of the grid-like phosphor coating films 60 of the respective colors in the block region 72 become the same. When the difference image detection 54 is executed, a signal of only the defect 57 is obtained in the difference image 56. Note that the positional relationship between the block regions 71 and 72 can be arranged in the vertical direction. In this case, the size of the block in the vertical direction (Y direction) is set to an integral multiple of Py. Accordingly, in the binarized image 58, a binarized signal of the binarized defect 59 is obtained. Note that, in the embodiment shown in FIG. 7, the size of the block in the vertical direction (Y direction) does not necessarily need to be set to an integral multiple of Py. The same applies to the size of the block in the horizontal direction (X direction) in the embodiment shown in FIG. The reason will be described later.

  Although the embodiment shown in FIG. 3 shows a case where the positional relationship between the block 31 and the block 32 is located close to the Y direction (vertical positional relationship in FIG. 3), When moving the block 32, it is desirable to maintain this relationship. This is because both blocks need to have the same pattern in order to detect the difference image between the two blocks 31 and 32 as described with reference to FIG. Note that, if the same pattern is used, it is not necessary to be particularly close to each other. However, at least the block size in the arrangement direction of the blocks 31 and 32 or the blocks 71 and 72 is an integral multiple of the average pitch in the direction. , The positioning of the blocks 31 and 32 or the blocks 71 and 72 becomes extremely easy.

  In other words, regardless of the moving direction of the imaging unit 6 in the X-axis direction or the Y-axis direction, the positions of the blocks 31 and 32 in the X-axis direction are always set by the moving mechanism 7 as shown in FIG. Since the positions of the stripes of the respective colors in the block 31 and the block 32 can be easily matched if the positions in the Y direction of the block 31 and the block 32 are kept constant and the positions of the blocks 31 and 32 only match in the Y direction. , Only the defect 55 can be easily detected. Similarly, in FIG. 7, only the positions of the block 71 and the block 72 in the X direction need be matched. In the above description, the difference image between two blocks (two regions) has been described. However, it goes without saying that it is possible to easily inspect more than two blocks at the same time in order to increase the inspection efficiency. For example, in a case where two blocks are arranged in each of the horizontal direction and the vertical direction and a total of four blocks are inspected at the same time, the size of the block is set to an integral multiple of Px in the horizontal direction, and The direction may be set to an integral multiple of Py. If the arrangement direction of the imaging unit 6 and the arrangement direction of the blocks 31 and 32 or the blocks 71 and 72 are set to be the same direction, it is easily affected by distortion of an optical system such as a lens of a camera. (In the example of the imaging unit 6 shown in FIG. 2, the arrangement direction of the imaging unit 6 is the X direction, and the moving direction of the imaging unit 6 is the Y direction.) Therefore, when the moving direction of the imaging unit 6 matches the arrangement direction of the blocks, the arrangement direction of the line sensors of the imaging unit 6 is different from the arrangement direction of the blocks, so that the inspection accuracy can be further improved. Can be.

  Next, the operation of the pattern defect inspection apparatus of the present invention will be described with reference to FIG. First, as a first step 81, when the glass substrate 2 coated with the grid-like phosphor coating film 60 (for example, (R) phosphor) is carried in and fixed to the mounting table 1, the imaging unit 6 is moved by the moving mechanism 7 to Y. Imaging is started from the origin 0 of the axis.

  In the second step 82, an inspection area is detected. This is when the line sensor camera first receives ultraviolet light, and all processing steps are started based on this.

  In the third step 83, the pitches of the lattice-shaped phosphor coating film 60 in the X direction and the Y direction are calculated as described with reference to FIG.

  In the fourth step 84, the positional relationship and the size (dimension) of the comparison block are determined. That is, the positional relationship between the two blocks to be compared is determined, and two blocks having a size that is an integral multiple of the pitch in the X direction and the Y direction calculated in the third step are determined as described above. At this time, as described above, for example, at least the size in the arrangement direction of the blocks is determined to be an integral multiple of the average pitch in the direction. For example, if the moving direction of the imaging unit 6 is the Y direction as shown in FIG. 3, the positional relationship between the two blocks is the vertical positional relationship, and if the moving direction of the imaging unit 6 is the X direction as shown in FIG. The positional relationship between the blocks is selected so as to be a horizontal positional relationship.

  In each of the embodiments described above, the positional relationship between the two blocks is close to each other without any gap. However, depending on the processing method, some blocks may overlap, or some It is also possible to capture an image with a blank.

  In a fifth step 85, a difference image between the two blocks is obtained over the entire glass substrate such as a plasma display panel to be inspected while maintaining the positional relationship between the two blocks determined in the fourth step.

  In a sixth step 86, the luminance signal level obtained from the difference image obtained in the fifth step is compared with a defect determination level (threshold). If there is a difference signal level higher than the defect determination level, this is determined as a pattern defect. Is determined. The defect determination level (threshold) is set to about 50% of the highest level obtained from the image signal. However, the setting can be changed experimentally or as needed in the course of the inspection, if necessary. is there.

  The above-described steps are sequentially performed on, for example, the R, G, and B color phosphors of the printed or coated grid phosphor coating film 60. Of course, as described above, when a defect is detected in the inspection of the R phosphor, the process of applying or printing the phosphor of the next color is stopped, and the glass substrate proceeds to the phosphor removal process. Will be played.

  Although the present invention has been described in detail above, the pattern defect inspection method of the present invention employs a method of detecting a defect with a difference image of two blocks. There is a problem that it is not possible to determine whether a defect is present in the image. However, it can be easily determined by shifting the block by one and performing a similar defect inspection. Application 2002-280694 (filed on Sep. 26, 2002) The pattern defect inspection apparatus and the pattern defect inspection method are described in detail in FIG.

  As described above, the present invention has been described in detail. However, the present invention is not limited to the pattern defect inspection apparatus and the pattern defect inspection method for a glass substrate such as a plasma display panel described herein. It goes without saying that the present invention can be widely applied to an inspection apparatus and a pattern defect inspection method.

1 is a block diagram showing one embodiment of a pattern defect inspection device according to the present invention. FIG. 3 is an enlarged view of a part of one embodiment of the present invention. FIG. 4 is a diagram for explaining the operation principle of the present invention. FIG. 4 is a diagram for explaining the operation principle of the present invention. FIG. 5 is a diagram illustrating the principle for detecting a defect of a phosphor stripe based on a difference image. FIG. 6 is an explanatory diagram in the case where the principle of defect detection based on the difference image in FIG. 5 is applied to a grid-like phosphor coating film. FIG. 9 is a diagram for explaining the operation principle of another embodiment of the present invention. FIG. 4 is a diagram for explaining one embodiment of the defect inspection method of the present invention.

Explanation of reference numerals

  1: glass substrate mounting table, 2: glass substrate, 3: phosphor stripe, 4 ultraviolet light source, 5: optical system, 6: imaging unit, 7: moving mechanism, 8: image processing unit, 9: display unit, 10 : Drive unit, 11: control unit, R: red phosphor coating film, G: green phosphor coating film, B: blue phosphor coating film, 31, 32: block area, 54: difference image detection, 55: defect, 56: difference image, 57: defect difference image, 58: binarized data, 59: binarized defect data.

Claims (3)

  An imaging unit that images a pattern of a grid-like phosphor coating film formed on a substrate; a moving mechanism unit that moves the imaging unit along the pattern; and an image processing that receives a video signal from the imaging unit And a display unit for displaying the output of the image processing unit, and a control unit for controlling the moving mechanism unit and the image processing unit, wherein the image processing unit is a grid of the pattern of the grid phosphor coating film. A grid pitch calculator for calculating a pitch, a comparator for comparing image data of at least two areas having an integral multiple of the grid pitch, and a defect detector for detecting a defect of the pattern based on the comparison result. A pattern defect inspection apparatus characterized in that:   Imaging the pattern of the grid-like phosphor coating film formed on the substrate; calculating the grid pitch of the pattern of the grid-like phosphor coating film from the image data obtained by the imaging; A pattern defect inspection method, comprising: comparing image data of at least two regions having a size of an integral multiple of the pitch; and detecting a defect of the pattern based on the comparison result.   3. The pattern defect inspection method according to claim 2, wherein the step of comparing image data of at least two areas having an integral multiple of the lattice pitch from the image data is adjacent to the pattern of the lattice-shaped phosphor coating film. A pattern defect inspection method, comprising: selecting two block regions; and detecting a difference image between image data obtained from the two block regions.

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