JP5532025B2 - Glass substrate inspection system and glass substrate manufacturing method - Google Patents

Description

  The present invention relates to a glass substrate inspection system and a glass substrate manufacturing method.

  2. Description of the Related Art Conventionally, as a system for inspecting a glass substrate, a system including a take-out device that takes out a glass substrate from a cassette and an inspection device that inspects the main plane of the glass substrate taken out from the cassette by the take-out device is known (for example, , See Patent Document 1).

  In addition, as an inspection apparatus for inspecting the storage status of the glass substrate stored in the cassette, an apparatus that includes an imaging device that images the entire cassette and inspects the storage status by performing image processing on the image captured by the imaging device is proposed. (For example, refer to Patent Document 2).

JP 2003-95372 A JP2011-70729A

  A cassette for storing uninspected glass substrates has a plurality of storage positions in which glass substrates can be stored, and one glass substrate can be stored in each storage position, but glass substrates are stored in some storage positions. It may not have been done.

  The conventional take-out apparatus performs an operation of taking out the glass substrate from the storage position for each cassette storage position under the control of the control device. Since this operation is performed for all the storage positions and also for the storage position without the glass substrate, the inspection efficiency is poor.

  This invention is made | formed in view of the said subject, Comprising: It aims at providing the glass substrate test | inspection system excellent in test | inspection efficiency.

According to one aspect of the invention,
A take-out device that takes out a glass substrate from a cassette, an inspection device that inspects the glass substrate taken out from the cassette by the take-out device, and an imaging device that takes an image of the cassette, and the cassette can store the glass substrate. A glass substrate inspection system having a plurality of storage positions and a groove part into which the glass substrate is inserted at each storage position ,
An execution unit for causing the take-out apparatus to perform an operation of taking out the glass substrate from the storage position for each storage position;
Presence / absence of determining the presence / absence of the glass substrate for each storage position by setting a plurality of processing areas corresponding to the plurality of storage positions in the image captured by the imaging device and performing image processing on each processing area A determination unit ;
A plate thickness discriminating unit that discriminates whether or not the plate thickness of the glass substrate at the storage position is within a predetermined range for each storage position by the image processing of each processing region ;
The execution unit skips the take-out operation for the storage position determined that the glass substrate is not present by the presence / absence determination unit , and the plate thickness is determined to be out of a predetermined range by the plate thickness determination unit. Skip the take-out operation for the storage position,
The imaging device includes a camera that images the cassette at a stop position on a conveyance path, and a light source that illuminates the cassette at the stop position,
The plate thickness determination unit is configured such that a plate thickness of the glass substrate at the storage position is based on an image of a light reflection portion that reflects light from the light source toward the camera at the glass substrate at the storage position. A glass substrate inspection system for determining whether or not a predetermined range is satisfied is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the glass substrate inspection system excellent in inspection efficiency can be provided.

The side view of the glass substrate inspection system by one Embodiment of this invention Top view of an example of a state in which a glass substrate is accommodated in a cassette Explanatory drawing of an example of a spindle in an inspection device (1) Explanatory drawing of an example of a spindle in an inspection device (2) Explanatory drawing of an example of the imaging device in the conveyance direction view of a cassette Schematic diagram of an example of an image captured by a camera Partial enlarged view of an example of an image captured by a camera A flowchart of an example of processing performed by the state determination unit A flowchart of an example of processing performed by the presence / absence determination unit Flow chart of an example of processing performed by the plate thickness discrimination unit Schematic of an example of a table produced by the presence / absence determining unit and the plate thickness determining unit

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted.

  FIG. 1 is a side view of a glass substrate inspection system according to an embodiment of the present invention. In the following drawings, the X direction represents the longitudinal direction of the cassette 30, and the Z direction represents the vertical direction. The X direction and the Z direction are directions orthogonal to each other.

  The glass substrate inspection system 10 includes a take-out device 40 that takes out the glass substrate 20 from the cassette 30 and an inspection device 50 that inspects the glass substrate 20 taken out from the cassette 30 by the take-out device 40. Based on the inspection result of the inspection apparatus 50, the glass substrate 20 is classified into a good product having no defect and a defective product having a defect. Non-defective products and defective products are stored in different collection cassettes.

  The glass substrate inspection system 10 further includes an imaging device 60 that images the cassette 30 and a transport device 70 that transports the cassette 30 to the imaging device 60 and the take-out device 40 in this order. The conveyance device 70 is constituted by a belt conveyor, for example, and forms a conveyance path for conveying the cassette 30 in the X direction. A supply device that supplies the cassette 30 on the conveyance path is provided on the upstream side of the conveyance path, and a collection device that collects the cassette 30 on the conveyance path is provided on the downstream side of the conveyance path. On the conveyance path, a plurality of cassettes 30 are arranged at intervals in the conveyance direction (X direction).

  The glass substrate inspection system 10 further includes a control device 80 that controls the take-out device 40, the inspection device 50, the imaging device 60, and the transport device 70.

(Glass substrate)
The glass substrate 20 is a glass substrate for magnetic recording media, for example. The glass substrate 20 has a disk shape, and a circular hole 21 (see FIG. 5) is formed through the center.

  The glass substrate 20 of the present embodiment is for a magnetic recording medium. For example, for a flat panel display (FPD) such as a liquid crystal display or an organic EL display, for an optical component such as an optical pickup element or an optical filter, or for a photo It may be used for a mask and its use is not particularly limited.

  The glass type of the glass substrate 20 is appropriately selected depending on the application, and may be, for example, amorphous glass, crystallized glass, or tempered glass having a tempered layer on the surface layer. The tempered glass may be chemically tempered glass or air-cooled tempered glass.

  The manufacturing method of the glass substrate 20 is not specifically limited, For example, the float method, the fusion method, the press method, the redraw method etc. are used.

(cassette)
FIG. 2 is a top view of an example of a state in which a glass substrate is stored in a cassette. In the following drawings, the X direction represents the longitudinal direction of the cassette 30, and the Y direction represents the width direction of the cassette 30. The X direction and the Y direction are directions orthogonal to each other. FIG. 2 shows a state in which the glass substrates 20A and 20B having different thicknesses are stored in the cassette 30. FIG. FIG. 2 shows a state where the glass substrate 20 is not stored in a part of the plurality of storage positions.

  The cassette 30 has a box shape opened upward, and a partition portion 32 projects from an inner side surface 31 of the cassette 30. A plurality of partition portions 32 are formed at intervals in the longitudinal direction (X direction) of the cassette 30, and the interval between the partition portions 32 is larger than the plate thickness of the glass substrate 20. The glass substrate 20 is inserted into a groove 33 formed between the partition portions 32 and stored in the cassette 30 in a state of being separated one by one. The cassette 30 has a plurality of (for example, 25) storage positions in which the glass substrate 20 can be stored, and the plurality of storage positions are arranged at intervals in a predetermined direction (X direction).

  The cassette 30 has two linear portions 34 to 35 parallel to each other at the opening edge. The longitudinal direction of each linear part 34-35 is parallel to the direction (X direction) in which a plurality of storage positions are arranged.

(Removal device)
The take-out device 40 is a device that takes out the glass substrate 20 from the cassette 30 as shown in FIG. When taking out, the cassette 30 may be temporarily stopped at a predetermined position on the transport path, and a stopper for positioning the stop position may be disposed on the transport path.

  The take-out device 40 includes a movable body 41 that can move in the X direction with respect to the transport path, an extendable arm 42 that can extend and contract in the Z direction, a chuck mechanism 43 that is provided at the lower end of the extendable arm 42, and the like.

  The movable body 41 is movably supported by a guide rail 45 or the like, and is moved by a drive source 46 such as a motor. An upper end portion of the telescopic arm 42 is fixed to the movable body 41.

  The telescopic arm 42 is composed of, for example, a fluid pressure cylinder such as a pneumatic cylinder or a hydraulic cylinder, and can extend and contract in the vertical direction (Z direction). The chuck mechanism 43 moves up and down with respect to the movable body 41 by extending and contracting the extendable arm 42.

  The chuck mechanism 43 may have a general configuration. For example, as shown in FIG. 1, the chuck mechanism 43 may be a mechanism that holds the inner periphery of the glass substrate 20 at a plurality of locations, or a mechanism that holds the inner periphery and the outer periphery of the glass substrate 20. But you can.

  The take-out device 40 performs an operation of taking out the glass substrate 20 from the storage position for each storage position under the control of the execution unit 81 described later. The take-out operation is appropriately selected according to the configuration of the take-out device 40. In the present embodiment, the following operations (1) to (5) are included. (1) The cassette 30 and the movable body 41 are aligned in the X direction. The alignment is performed by moving the movable body 41 and / or moving the cassette 30. (2) Extend the telescopic arm 42 and insert the chuck mechanism 43 into the cassette 30. (3) The movable body 41 is moved in the X direction, and the chuck mechanism 43 is moved to one storage position. At this time, if the glass substrate 20 is stored in one storage position, the chuck mechanism 43 is inserted into the circular hole 21 of the glass substrate 20. (4) The chuck mechanism 43 is driven. At this time, if the glass substrate 20 is stored in one storage position, the chuck mechanism 43 chucks the glass substrate 20. (5) The telescopic arm 42 is contracted and the chuck mechanism 43 is taken out from the cassette 30. The series of taking-out operations (1) to (5) are performed for each storage position, and are sequentially performed from one end side to the other end side in the longitudinal direction (X direction) of the cassette 30. There may be a plurality of take-out devices 40. For example, in the case of two take-out devices, the take-out operation is sequentially performed from both longitudinal ends of the cassette 30 toward the center.

  The take-out device 40 of the present embodiment is a device that pulls up the glass substrate 20 from above the cassette 30. However, after the glass substrate 20 is pushed upward from the cassette 30 by a lift mechanism, the chuck mechanism 43 ( A mechanism that grips the inner periphery of the glass substrate 20 at a plurality of locations, a mechanism that clamps the inner periphery and the outer periphery of the glass substrate 20, or a mechanism that grips the outer periphery of the glass substrate 20 at a plurality of locations. An apparatus for chucking the glass substrate 20 may be used.

  The glass substrate 20 taken out by the take-out device 40 is transferred to a transport hand (not shown). The transport hand may have a general configuration, and has a mechanism for gripping the outer periphery of the glass substrate 20 at a plurality of locations, for example. The transport hand transfers the glass substrate 20 received from the take-out device 40 to the inspection device 50 and sets it on the spindle 54 of the inspection device 50.

(Inspection equipment)
The inspection apparatus 50 is an optical automatic inspection apparatus (AOI: Automatic Optical Inspection) that inspects the glass substrate 20. The inspection device 50 irradiates the main plane 22 of the glass substrate 20 with light and receives scattered light (or reflected light) from the irradiation position.

  For example, as shown in FIG. 1, the inspection device 50 receives a laser light source 51 that irradiates the main plane 22 of the glass substrate 20 with laser light, and light that receives scattered light (or reflected light) from the irradiation position of the laser light. It includes an element 52 and a spindle 54 that rotates the glass substrate 20. An optical system 53 such as a condensing lens for condensing laser light is provided between the laser light source 51 and the glass substrate 20, and spot light is formed on the main plane 22 of the glass substrate 20 by the optical system 53. The spot light is swirled on the main plane 22 of the glass substrate 20 that rotates with the spindle 54. When spot light strikes a defect present on the main plane 22, the amount of light received by the light receiving element 52 increases or decreases. The light receiving element 52 is configured by a photoelectric conversion element or the like, and transmits a signal corresponding to the amount of received light to the control device 80. The control device 80 determines the presence / absence of a defect based on a signal from the light receiving element 52 and classifies the defect into a non-defective product and a defective product with a defect. The non-defective product and the defective product are stored in different collection cassettes. Examples of the types of defects include cracks, unevenness, and deposits.

  In addition, although the test | inspection apparatus 50 of this embodiment test | inspects one main plane 22 of the glass substrate 20, you may test | inspect both main planes 22 and 23. FIG.

  3 to 4 are explanatory diagrams of an example of the spindle in the inspection apparatus 50. FIG. The spindle 54 grips the inner periphery of the glass substrate 20 and rotates together with the glass substrate 20. The spindle 54 may have a general configuration, for example, a cylindrical portion 55 that supports the inner periphery of the glass substrate 20 from the back surface side, and is disposed inside the cylindrical portion 55 in the axial direction with respect to the cylindrical portion 55. And a gripping claw 57 slidable in the radial direction as the shaft portion 56 moves. The shaft portion 56 has a truncated cone-shaped head portion 58, and the head portion 58 has a tapered surface 59 on the outer periphery that goes radially inward toward the right side in the drawing. A plurality of gripping claws 57 are disposed around the head 58, and each gripping claw 57 is in contact with the tapered surface 59 of the head 58.

  When the shaft portion 56 moves in the right direction from the state shown in FIG. 3, as shown in FIG. 4, the gripping claws 57 slide outward in the radial direction and are pressed against the inner peripheral surface of the glass substrate 20. Grip. On the other hand, when the shaft portion 56 moves leftward from the state shown in FIG. 4, the gripping claws 57 slide inward in the radial direction and move away from the inner peripheral surface of the glass substrate 20 as shown in FIG. 3. 20 is released. In the state shown in FIG. 3, the glass substrate 20 can be extracted from the spindle 54.

(Imaging device)
FIG. 5 is an explanatory diagram of the imaging device when the cassette 30 is viewed in the conveyance direction. FIG. 5 shows the cassette 30 cut away.

  The imaging device 60 includes a camera 61 that images the cassette 30 conveyed by the conveyance device 70, a light source 62 that illuminates the cassette 30, and a support member 63 that supports the camera 61 and the light source 62.

  The camera 61 is composed of, for example, a CCD camera or a CMOS camera, is installed above a predetermined position on the conveyance path, and images the entire cassette 30 from above. During imaging, the cassette 30 may be temporarily stopped at a predetermined position on the conveyance path, and a stopper for positioning the stop position may be provided on the conveyance path. At the time of imaging, the optical axis of the camera 61 coincides with the center of the cassette 30 when viewed from above.

  The light source 62 is disposed at a position that does not overlap the cassette 30 in a top view so as not to enter the imaging region of the camera 61, and is disposed obliquely above the cassette 30. The light source 62 is a linear light source in a direction (X direction) parallel to the linear portion 34 of the cassette 30 as shown in FIG. The length of the light source 62 is longer than the length of the linear portion 34 so that the light source 62 uniformly illuminates the entire linear portion 34, and the luminance of the light source 62 is substantially uniform in the longitudinal direction of the light source 62.

  As shown in FIG. 5, the light source 62 is disposed near one of the two linear portions 34 and 35. In order to selectively illuminate one of the linear portions 34, the light source 62 may be composed of an LED light source having higher directivity than a general fluorescent lamp.

  The glass substrate 20 in the cassette 30 illuminated by the light source 62 has a light reflecting portion 26 that reflects light from the light source 62 toward the camera 61. The light reflecting portion 26 is on the outer edge 27 of the glass substrate 20.

  FIG. 6 is a schematic diagram illustrating an example of an image captured by the imaging apparatus. FIG. 7 is a partially enlarged view of an example of an image captured by the imaging apparatus. 6 to 7, illustration of the partition portion 32, the groove portion 33, and the like of the cassette 30 is omitted for easy viewing of the drawings. Moreover, the image 34G of the linear part 34 of the cassette 30 and the image 26G of the light reflection part 26 of the glass substrate 20 are shown by a dot pattern. The portion indicated by the dot pattern is a portion where the luminance (brightness) of the pixel is higher than the other portions.

  An image 90 (hereinafter also referred to as “entire image 90”) captured by the imaging device 60 includes an image 30G of the cassette 30 and an image 20G of each glass substrate 20 housed in the cassette 30. The image 30G of the cassette 30 includes an image 34G of the linear portion 34 on the upper edge of the cassette 30. The image 20G of each glass substrate 20 includes an image 26G of the light reflecting portion 26.

  When only the glass substrate 20 having the same thickness is accommodated in the cassette 30, the width W in the X direction of the image 26G of the light reflection portion 26 (see FIG. 7) from the center in the X direction of the entire image 90 toward both ends in the X direction. May be small (or large). This is due to the influence of lens aberration of the camera 61. In order to remove this influence, a telecentric lens may be used as the lens of the camera 61.

  On the other hand, as shown in FIG. 6, when glass substrates 20A and 20B having different plate thicknesses are accommodated in the cassette 30, the widths in the X direction of the images 26AG and 26BG of the light reflecting portions 26A and 26B are the glass substrates 20A and 20B. It becomes the size according to the plate thickness.

(Control device)
The control device 80 performs image processing on the entire image 90 and controls the extraction device 40 based on the result of the image processing. The control device 80 is configured as a computer including a CPU, a recording medium (for example, ROM or RAM), and the like. The control device 80 stores computer programs corresponding to an execution unit 81, a state determination unit 82, a presence / absence determination unit 83, and a plate thickness determination unit 84, which will be described later, in a recording medium. The control device 80 implements the functions of the execution unit 81, the state determination unit 82, the presence / absence determination unit 83, and the plate thickness determination unit 84 by causing the CPU to execute these computer programs.

  Instead of the control device 80, an image processing device including a state determination unit 82, a presence / absence determination unit 83, and a plate thickness determination unit 84, and a PLC (Programmable Logic Controller) including an execution unit 81 may be used. The PLC is configured to be able to send and receive information to and from the image processing apparatus.

(Execution part)
The execution unit 81 causes the take-out device 40 to perform an operation of taking out the glass substrate 20 from the storage position for each storage position. At this time, the cassette 30 may be temporarily stopped at a predetermined position on the conveyance path. Details of the execution unit 81 will be described later.

(Status judgment part)
The state determination unit 82 performs image processing on the entire image 90 to determine whether the positional relationship between the linear portion 34 of the cassette 30 and the imaging device 60 is in a normal state.

FIG. 8 is a flowchart of an example of processing performed by the state determination unit. The processing after S101 shown in FIG. 8 is started when the control device 80 receives image data from the imaging device 60, for example.
First, the state determination unit 82 binarizes the entire image 90 based on whether or not the luminance (brightness) of the pixel is equal to or higher than a threshold (for example, divides the entire image 90 into a white pixel and a black pixel) (step S101).

  Next, the state determination unit 82 performs a labeling process on the binarized image (assigns the same number to continuous white pixels or continuous black pixels) (step S102), and detects the image 34 of the linear portion 34. (Step S103). In order to improve the speed of the labeling process, unnecessary parts in the binarized image may be masked before the labeling process, and the unnecessary parts may be excluded from the target of the labeling process.

  Next, the state determination unit 82 extracts feature values of the image 34G of the linear portion 34 (for example, the occupied area in the entire image 90, the inclination with respect to the reference line in the entire image 90, the image coordinates in the entire image 90, etc.). (Step S104).

  Next, the state determination unit 82 compares the extracted feature value with the reference value (step 105), and determines whether the positional relationship between the linear portion 34 of the cassette 30 and the imaging device 60 is normal (step). S106). The reference value is determined by a test and is recorded in advance on a recording medium.

  For example, when the absolute value of the difference between the feature value and the reference value is equal to or less than the threshold value, the state determination unit 82 determines that the positional relationship is in a normal state. On the other hand, when the absolute value of the difference between the feature value and the reference value exceeds the threshold value, the state determination unit 82 determines that the positional relationship is in an abnormal state.

  When it is determined that the positional relationship is in an abnormal state, for some reason, the cassette 30 is not set correctly on the transport path, so the control device 80 stops the predetermined operation of the glass substrate inspection system 10, and A display unit such as a display, a lamp, a buzzer, and the like are controlled to notify the user of the abnormality. The user checks the cause of the abnormality, removes the cause, and then cancels the stop of the glass substrate inspection system 10. The user can cancel the stop of the glass substrate inspection system 10 without removing the cause. As will be described in detail later, the cassette 30 determined to be abnormal may be excluded from processing by the take-out device 40 and may be processed from the next cassette.

  The state determination unit 82 of the present embodiment performs binarization processing and labeling processing to detect the image coordinates of the image 34G of the linear portion 34, but the image processing method is not particularly limited. For example, the state determination unit 82 may perform a pattern matching process using a template. In this case, the normal state is determined depending on whether the similarity between the image 34G of the linear portion 34 and the template exceeds a threshold value. Determine whether or not. In addition, the state determination unit 82 may obtain a point where the luminance of the pixel changes suddenly by differentiation (primary differentiation or secondary differentiation) and detect the image coordinates of the outline of the linear portion 34.

(Presence / absence judgment unit)
The presence / absence determination unit 83 performs image processing on the entire image 90 and determines the presence / absence of the glass substrate 20 for each storage position.

  FIG. 9 is a flowchart of an example of processing performed by the presence / absence determining unit. The processing after S201 shown in FIG. 9 is started when the control device 80 receives image data from the imaging device 60, for example.

  The processing after S201 is performed when the state determination unit 82 determines that the positional relationship is in a normal state, and may not be performed when it is determined that the state is in an abnormal state.

  First, the presence / absence determination unit 83 sets a plurality of processing areas 91 corresponding to a plurality of storage positions in the image 90 (step S201). The number of processing regions 91 is the same as the number of storage positions (that is, the number of groove portions 33). A plurality of processing areas 91 are arranged in the X direction. The processing areas 91 may be separated from each other as shown in FIG.

  The image coordinates of each processing area 91 are set by a test or the like, and those recorded in advance on a recording medium are read out and used. The test is performed by storing the glass substrates 20 one by one in each storage position, and the image coordinates of each processing region 91 are such that the image 26G of the light reflecting portion 26 of the corresponding glass substrate 20 is included in each processing region 91. Set to

  The image coordinates of each processing area 91 may be corrected based on the image coordinates of the linear portion 34 detected by the state determination unit 82.

  The dimension in the X direction of each processing region 91 (hereinafter simply referred to as “region size”) may be set for each of the sections 90a to 90c obtained by dividing the entire image 90 into three in the X direction. The region sizes Da and Dc (Da = Dc) in the sections 90a and 90c at the end portions in the X direction are set smaller (or larger) than the region size Db in the section 90b at the center portion in the X direction (Da = Db in the drawing). = Dc). This setting is performed in accordance with the X-direction width W (see FIG. 7) of the image 26G of the light reflecting portion 26 of the glass substrate 20 having the same plate thickness becoming smaller (or larger) toward the end in the X direction. Therefore, the influence of the lens aberration of the camera 61 can be reduced.

  In the present embodiment, the entire image 90 is divided into three sections 90a to 90c in the X direction, but the number of divisions is not particularly limited as long as it is three or more. For example, the number of divisions may be the same as the number of storage positions.

  In the present embodiment, the division is performed for both the purpose of adjusting the X-direction dimension of the processing region 91 and the purpose described later (the purpose of adjusting the reference value to be compared with the feature value extracted from the processing region 91). However, division may be performed for either purpose.

  Next, the presence / absence determination unit 83 binarizes the image of each processing area 91 depending on whether or not the luminance (brightness) of the pixel is equal to or greater than a threshold (for example, separates the image into white pixels and black pixels) (step S202). White pixels are pixels whose luminance is equal to or higher than a threshold value, and black pixels are pixels whose luminance is lower than the threshold value.

  Next, the presence / absence determination unit 83 performs a labeling process on the binarized image of each processing area 91 (assigns the same number to consecutive white pixels) (step S203).

  Next, the presence / absence determining unit 83 detects whether or not the image 26G of the light reflecting portion 26 is included for each processing region 91 (step S204). For example, the image 26G is included when the area (feature value) of continuous white pixels is equal to or greater than the reference value, and it is detected that the image 26G is not included when the area is less than the reference value.

  The reference value may be set for each of the areas 90a to 90c. For example, the reference values in the X direction end areas 90a and 90c are set to be smaller (or larger) than the reference position in the X direction center area 90c. This setting is performed in accordance with the X-direction width W (see FIG. 7) of the image 26G of the light reflecting portion 26 of the glass substrate 20 having the same plate thickness becoming smaller (or larger) toward the end in the X direction. Therefore, the influence of the lens aberration of the camera 61 can be reduced.

  Next, the presence / absence determining unit 83 determines whether or not the glass substrate 20 is present at the storage position corresponding to each processing region 91 based on the result of step S204 (step S205). Specifically, when the image 26 </ b> G is included in one processing area 91, it is determined that the glass substrate 20 is in a storage position corresponding to the one processing area 91. If the image 26G is not included in one processing area 91, it is determined that there is no glass substrate 20 in the storage position corresponding to the one processing area 91.

  Finally, the presence / absence determining unit 83 records a table (see FIG. 11) in which the storage position identification information (for example, identification number) and the presence / absence of the glass substrate 20 are associated with each other on the recording medium (step S206). The table is recorded in association with an ID for identifying the cassette 30.

  Note that the presence / absence determination unit 83 of the present embodiment performs binarization processing and labeling processing to determine whether or not the image 26G of the light reflection portion 26 is included for each processing region 91. The method is not particularly limited. For example, the presence / absence determining unit 83 may detect and determine the image 26G of the light reflecting portion 26 by performing a pattern matching process using a template. In addition, the presence / absence determination unit 83 may determine a point where the luminance of the pixel changes suddenly by differentiation (first-order differentiation or second-order differentiation), detect the outline of the image 26G of the light reflection portion 26, and perform the determination.

(Thickness discrimination part)
The plate thickness determination unit 84 performs image processing on the entire image 90 and determines whether the plate thickness of the glass substrate 20 at the storage position is within a predetermined range for each storage position. When a plurality of types of glass substrates having different thicknesses are manufactured on the glass substrate production line, it is possible to detect that the plurality of types of glass substrates are mixed by mistake. The plate thickness discriminating unit 84 does not have to perform a process described later for the storage position determined by the presence / absence determining unit 83 that the glass substrate 20 is not present.

  Note that either the processing of the presence / absence determination unit 83 or the processing of the plate thickness determination unit 84 may be performed first or may be performed simultaneously.

  FIG. 10 is a flowchart illustrating an example of processing performed by the plate thickness determination unit. The processing after S301 shown in FIG. 10 is started when the control device 80 receives image data from the imaging device 60, for example.

  The processing after S301 is performed when the state determination unit 82 determines that the positional relationship is in a normal state, and may not be performed when it is determined that the state is in an abnormal state.

  First, the plate thickness discriminating unit 84 examines the change in luminance of the pixels in each processing region 91 and detects the width W in the X direction of the image 26G of the light reflecting portion 26 (hereinafter also simply referred to as “image width W”) ( Step S301). The image width W is calculated as a distance between two points 92 and 93 (see FIG. 7) where the luminance changes suddenly in the X direction.

  A line 94 for examining the change in luminance extends in the X direction. The line 94 may be a line passing through the center of gravity in the Y direction of one or a plurality of images 26G included in the entire image 90, or may be a line set by a test and recorded in advance on a recording medium.

  Next, the plate thickness determining unit 84 checks whether or not the detected image width W is within the reference range (step S302). The reference range may be set for each of the areas 90a to 90c. For example, the lower limit value and the upper limit value of the reference range in the sections 90a and 90c at the end portions in the X direction are set to be smaller (or larger) than the lower limit value and the upper limit value of the reference range in the section 90b at the center portion in the X direction. This setting is performed in accordance with the X-direction width W (see FIG. 7) of the image 26G of the light reflecting portion 26 of the glass substrate 20 having the same plate thickness becoming smaller (or larger) toward the end in the X direction. Therefore, the influence of the lens aberration of the camera 61 can be reduced.

  Next, the plate thickness determining unit 84 determines whether or not the plate thickness of the glass substrate 20 is within a predetermined range based on the investigation result of step S302 (step S303). Specifically, when the image width W is within the reference range, it is determined that the plate thickness of the glass substrate 20 is within the predetermined range. If the image width W is outside the reference range, it is determined that the thickness of the glass substrate 20 is outside the predetermined range.

  Finally, the plate thickness determination unit 84 records a table (see FIG. 11) in which the identification information (for example, the identification number) of the storage position is associated with the determination result of the plate thickness of the glass substrate 20 on the recording medium (see FIG. 11). Step S304). In the table shown in FIG. 11, “◯” indicates that the plate thickness is determined to be within the predetermined range, “×” indicates that the plate thickness is determined to be outside the predetermined range, and “−” indicates glass. This means that the plate thickness was not determined because there was no plate.

(Execution part)
The execution unit 81 performs an operation to take out the glass substrate 20 from each storage position on the take-out device 40 based on the determination result of the state determination unit 82, the determination result of the presence / absence determination unit 83, and the determination result of the plate thickness determination unit 84. Let The execution unit 81 performs processing with reference to a table (see FIG. 11) recorded on the recording medium.

  For example, when the state determination unit 82 determines that the positional relationship is an abnormal state, the execution unit 81 does not cause the extraction device 40 to perform the extraction operation for all the storage positions of the cassette 30. In this case, the cassette 30 is not correctly set on the transport path for some reason.

  In addition, the execution unit 81 causes the extraction device 40 to skip the extraction operation for the storage position determined by the presence / absence determination unit 83 that the glass substrate 20 is not present. The execution unit 81 causes the take-out device 40 to perform only the take-out operation with respect to the storage position where it is determined that the glass substrate 20 is present, so that the useless take-out operation is not performed and the inspection efficiency is improved.

  In addition, the execution unit 81 causes the extraction device 40 to skip the extraction operation for the storage position of the glass substrate 20 in which the plate thickness is determined to be out of the predetermined range by the plate thickness determination unit 84. The execution unit 81 causes the take-out device 40 to perform only the take-out operation with respect to the storage position of the glass substrate 20 in which the plate thickness is determined to be within the predetermined range. Thereby, since only the glass substrate 20 having a desired plate thickness is chucked in the take-out device 40 or the inspection device 50, the load applied to the glass substrate 20 is stabilized, the glass substrate 20 is prevented from being damaged, and consequently the glass substrate inspection system. Contamination of the clean room in which 10 is installed is prevented. In addition, since only the glass substrate 20 having a desired thickness is inspected by the inspection device 50, it is possible to prevent the focus of the laser light from deviating and to prevent an erroneous inspection result from being obtained.

  Further, when there is a glass substrate whose thickness is determined to be out of the predetermined range by the thickness determination unit 84, the execution unit 81 may not cause the extraction device 40 to perform the extraction operation for all the storage positions of the cassette 30. . In this case, because the non-standard glass substrate 20 is mixed in the cassette 30, there is an abnormality in the production line of the glass substrate 20. The control device 80 stops a predetermined operation of the glass substrate inspection system 10 and controls a display unit such as a display, a lamp, a buzzer, and the like to notify the user of the abnormality. The user checks the cause of the abnormality, removes the cause, and then cancels the stop of the glass substrate inspection system 10. The user can also cancel the stop without removing the cause.

(Glass substrate manufacturing method)
The manufacturing method of a glass substrate is selected according to the use of a glass substrate, for example, when the use of a glass substrate is for magnetic recording media, it has the following processes (1) to (6). (1) A glass base plate is processed to produce a disk-shaped glass substrate having a circular hole in the center. (2) The corners of the outer periphery and inner periphery of the glass substrate are chamfered. (3) The front surface and the back surface (both main surfaces) of the glass substrate are lapped. In lapping, loose abrasive wraps (for example, abrasive grains such as alumina abrasive grains and silicon carbide abrasive grains and a metal surface plate are used) or fixed abrasive wraps (for example, grindstones such as diamond abrasive grains) are used. A fixed abrasive tool is used). (4) The outer peripheral surface and inner peripheral surface (including the chamfered portion) of the glass substrate are end-polished. (5) Both main surfaces of the glass substrate are polished. In main surface polishing, abrasive grains having an average particle diameter smaller than that of lapping and a resin-made polishing pad are used. There is no limit to the number of times of main surface polishing, and a plurality of types of main surface polishing with different polishing pads and polishing agents may be performed. (6) The glass substrate is washed and dried to produce a glass substrate for a magnetic recording medium. A magnetic disk can be manufactured by forming a thin film such as a magnetic layer on the magnetic recording medium glass substrate.

  Moreover, the manufacturing method of the glass substrate for magnetic recording media is the glass substrate cleaning (inter-process cleaning) and the glass substrate surface (entire surface or a part of the glass substrate (for example, between the steps (1) to (6) (for example, Etching (inter-process etching) of at least a part of the main plane, the inner peripheral end face, and the outer peripheral end face) may be performed. Moreover, you may implement the reinforcement | strengthening process (for example, chemical strengthening process) which forms a reinforcement layer in the surface layer of a glass substrate before a grinding | polishing process, after a grinding | polishing process, or between grinding | polishing processes.

  By the way, at the time of implementation of the above-mentioned steps (1) to (6), the glass substrate may be scratched at the time of carrying the glass substrate between these steps or between steps. Therefore, in the present embodiment, after the step (6), an inspection step by the glass substrate inspection system 10 is performed. This can improve the yield and manufacturing cost of the magnetic disk.

  In the present embodiment, the inspection process is performed after the process (6), but the present invention is not limited to this. That is, the inspection step may be performed after the processing step of processing the glass plate, and may be performed between the step (4) and the step (5), for example. Furthermore, the present invention is not limited to a method for manufacturing a glass substrate for a magnetic recording medium, but may be applied to a general method for manufacturing a glass plate such as a method for manufacturing a glass substrate for FPD or a glass substrate for photomask.

  As mentioned above, although one Embodiment of this invention was described, this invention is not restrict | limited to said embodiment. Various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention.

  For example, the glass substrate inspection system 10 of the present embodiment includes the imaging device 60 that images the cassette 30, but may include another device. As another apparatus, for example, a sensor configured by a light source that irradiates a laser beam onto the cassette 30 and a light receiving element that receives reflected light when the laser beam is reflected by the glass substrate 20 housed in the cassette 30. Etc. This sensor may be a line sensor in which a plurality of light sources and light receiving elements are arranged in a direction parallel to the longitudinal direction (X direction) of the cassette 30. The light receiving element may receive the transmitted light when the laser light passes (transmits) through the cassette 30. In this case, the light receiving element is arranged on the side opposite to the light source with the cassette 30 as a reference.

DESCRIPTION OF SYMBOLS 10 Glass substrate inspection system 20 Glass substrate 21 Circular holes 24 and 25 Main plane 30 Cassette 34 Straight line part 40 Extraction apparatus 50 Inspection apparatus 60 Imaging apparatus 61 Camera 62 Light source 80 Control apparatus 81 Execution part 82 State judgment part 83 Existence judgment part 84 Plate Thickness Discriminating Unit 90 Images 90a to 90c Imaged by Imaging Device Area 91 Processing Area

Claims (7)

A take-out device that takes out a glass substrate from a cassette, an inspection device that inspects the glass substrate taken out from the cassette by the take-out device, and an imaging device that takes an image of the cassette, and the cassette can store the glass substrate. A glass substrate inspection system having a plurality of storage positions and a groove part into which the glass substrate is inserted at each storage position ,
An execution unit for causing the take-out apparatus to perform an operation of taking out the glass substrate from the storage position for each storage position;
Presence / absence of determining the presence / absence of the glass substrate for each storage position by setting a plurality of processing areas corresponding to the plurality of storage positions in the image captured by the imaging device and performing image processing on each processing area A determination unit ;
A plate thickness discriminating unit that discriminates whether or not the plate thickness of the glass substrate at the storage position is within a predetermined range for each storage position by the image processing of each processing region ;
The execution unit skips the take-out operation for the storage position determined that the glass substrate is not present by the presence / absence determination unit , and the plate thickness is determined to be out of a predetermined range by the plate thickness determination unit. Skip the take-out operation for the storage position,
The imaging device includes a camera that images the cassette at a stop position on a conveyance path, and a light source that illuminates the cassette at the stop position,
The plate thickness determination unit is configured such that a plate thickness of the glass substrate at the storage position is based on an image of a light reflection portion that reflects light from the light source toward the camera at the glass substrate at the storage position. A glass substrate inspection system for discriminating whether or not a predetermined range is satisfied . The execution unit, when the plate thickness by the thickness determination unit is a glass substrate it is determined that the predetermined range, a glass substrate according to claim 1 for stopping the take-out operation for all of the storage position of the cassette Inspection system. The plurality of processing areas are arranged in a predetermined direction,
Wherein said predetermined dimension is a glass substrate inspection system according to claim 1 or 2 is set to the image for each area divided into three or more in the predetermined direction of the processing region. The presence / absence determination unit performs image processing on each processing region to extract a feature value of each processing region, compares the extracted feature value with a reference value, and determines the presence or absence of the glass substrate for each storage position. ,
The plurality of processing areas are arranged in a predetermined direction,
The glass substrate inspection system according to any one of claims 1 to 3 , wherein a reference value to be compared with a feature value of each processing region is set for each of the sections obtained by dividing the image into three or more in the predetermined direction. . The cassette has a box shape with an open top, and has a linear portion on the upper edge,
The glass substrate inspection system includes a state determination unit that determines whether the positional relationship between the linear portion of the cassette and the imaging device is normal by performing image processing on an image captured by the imaging device. In addition,
The said execution part stops the said taking-out operation | movement with respect to all the storage positions of the said cassette, when the said positional relationship is judged that the said positional relationship is an abnormal state by any one of Claims 1-4. Glass substrate inspection system. The glass substrate is a glass substrate inspection system according to any one of claims 1 to 5, which is a glass substrate for a magnetic recording medium having a circular hole in the center. The manufacturing method of the glass substrate which has an inspection process by the glass substrate inspection system as described in any one of Claims 1-6 .

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