JP2012163339A - Inspection device of transparent substrate, inspection method of transparent substrate, and manufacturing method of glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device of transparent substrates capable of efficiently inspecting transparent substrates including such as glass substrates and transparent resin substrates, an inspection method of transparent substrates, and a manufacturing method of glass substrates having an inspection process to inspect glass substrates by the inspection method of transparent substrates.SOLUTION: An inspection device 10 comprises lighting means 11a which allows the cross section of a transparent substrate 72 and the peripheral part thereof to be exposed to the light from an oblique direction, imaging means 12a which receives the transmitted beams of the light radiated from the lighting means 11a so as to image the picture of the cross section, and picture processing means 13 which calculates the area of the cross section based on the picture of the cross section taken by the imaging means 12a.

Description

  The present invention relates to a transparent substrate inspection apparatus for inspecting a transparent substrate, a transparent substrate inspection method, and a glass substrate manufacturing method including an inspection step of inspecting a glass substrate by the transparent substrate inspection method.

  For example, in a glass substrate manufacturing process by a float process, a molten glass material is formed into a plate-like glass ribbon on tin, slowly cooled and then crossed to produce a glass substrate of a predetermined size. Thereafter, the prepared glass substrate of a predetermined size is further cut vertically and transversely, and is cut into, for example, so-called G8 and G10 sizes, and the bottom surface (the surface in contact with tin) is polished to produce a mother glass.

  In the manufacturing process of the glass substrate, a glass substrate of a predetermined size prepared from a plate-shaped glass ribbon is extracted at regular intervals (for example, about once every two hours) and inspected to inspect the quality of the glass. Measurements may be made. The measured weight is fed back to the manufacturing process of the glass substrate to stabilize the melting amount (pull) of the glass raw material per unit time (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 5-17172

  However, extracting a glass substrate of a predetermined size prepared from a plate-shaped glass ribbon at regular intervals and inspecting has a problem of lowering the productivity of the mother glass. In addition, although the above description was performed using the glass substrate manufacturing process by the float method as an example, the same problem may occur in the glass substrate manufacturing process by the fusion method, or a transparent resin substrate (such as an acrylic plate). The same problem can occur in the manufacturing process of (1).

  The present invention has been made in view of the above points. A transparent substrate inspection apparatus, a transparent substrate inspection method, and the transparent substrate that can improve the efficiency of inspection of a transparent substrate including a glass substrate and a transparent resin substrate. It is an object of the present invention to provide a method for manufacturing a glass substrate, which includes an inspection process for inspecting a glass substrate by the inspection method.

  The inspection apparatus for a transparent substrate receives an illuminating unit that irradiates light from an oblique direction to a cross section of the transparent substrate and a peripheral portion thereof, and transmits light transmitted from the illuminating unit, and captures an image of the cross section. And image processing means for calculating an area of the cross section based on the image of the cross section taken by the imaging means.

  The method for inspecting the transparent substrate includes an illumination step of irradiating light from an oblique direction to a cross section of the transparent substrate and a peripheral portion thereof, and transmitted light of the light irradiated in the illumination step, and taking an image of the cross section. And an image processing step of calculating an area of the cross section based on the image of the cross section taken in the imaging step.

  The manufacturing method of this glass substrate makes it a requirement to have the inspection process which test | inspects a glass substrate with the inspection method of the transparent substrate which concerns on this invention.

  According to the present invention, a transparent substrate inspection apparatus, a transparent substrate inspection method, and an inspection for inspecting a glass substrate with the transparent substrate inspection method can efficiently inspect a transparent substrate including a glass substrate and a transparent resin substrate. The manufacturing method of the glass substrate which has a process can be provided.

It is a left view which illustrates typically the manufacturing process of the glass substrate by the float glass process concerning this Embodiment. It is a flowchart which illustrates the manufacturing process of the glass substrate by the float glass process which concerns on this Embodiment. It is a left view which illustrates typically the inspection apparatus of the glass substrate which concerns on this Embodiment. It is a front view which illustrates typically the inspection apparatus of the glass substrate which concerns on this Embodiment. It is a left view which illustrates typically the composition of the image pick-up means concerning this embodiment. It is a perspective view which illustrates typically the composition of the image pick-up means concerning this embodiment. It is a flowchart which illustrates the inspection method of the glass substrate which concerns on this Embodiment. It is a figure which illustrates the image of the one end part of the imaged cross section. It is a figure which illustrates the image of the other end part of the imaged cross section.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

  In the following description, an example in which the transparent substrate inspection apparatus or the transparent substrate inspection method according to the present embodiment is used for inspection in the glass substrate manufacturing process by the float method is shown, but the present invention is not limited thereto. You may use the inspection apparatus of the transparent substrate which concerns on a form, or the inspection method of a transparent substrate for the test | inspection in the manufacturing process of the glass substrate by a fusion method, and the manufacturing process of a transparent resin substrate (acrylic board etc.). In addition, when the transparent substrate inspection device or the transparent substrate inspection method according to the present embodiment is used for inspection in the glass substrate manufacturing process, it may be referred to as a glass substrate inspection device or a glass substrate inspection method. is there.

[Glass substrate manufacturing method]
First, the manufacturing process of the glass substrate by the float process is demonstrated. In the present embodiment, the previous process side may be referred to as upstream and the subsequent process side may be referred to as downstream with respect to a certain process.

  FIG. 1 is a left side view schematically illustrating a glass substrate manufacturing process by a float method according to this embodiment. In the present embodiment, the front side is the case where the glass substrate manufacturing process is viewed from the downstream side.

  Referring to FIG. 1, the glass substrate manufacturing process by the float method according to the present embodiment is roughly transported by a melting furnace 1, a float bath 2, a slow cooling furnace 3, a cutting device 4, a belt conveyor and the like. Means 5 and a glass substrate inspection apparatus 10 are provided. 1 and 3 to 6, the direction parallel to the direction in which the glass ribbon or glass substrate is conveyed (= direction of arrow A in FIG. 1 or the like) is the X direction, and the bottom surface of the glass ribbon or glass substrate (float bath). A direction parallel to the tin) and perpendicular to the X direction is defined as a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction.

  FIG. 2 is a flowchart illustrating a glass substrate manufacturing process by the float method according to this embodiment. Referring to FIGS. 1 and 2, first, in step S <b> 100, the glass raw material 70 is melted in the melting furnace 1. Although it does not specifically limit as a glass raw material, For example, the material which has quartz sand, limestone, soda ash, etc. as a main component can be used.

  Next, in step S110, the glass raw material 70 melted in the melting furnace 1 in step S100 is formed into a plate-like glass ribbon 71 in the float bath 2. Specifically, the glass raw material 70 melted in the melting furnace 1 in step S100 is supplied to the forehearth (not shown), and the glass raw material 70 is poured into the float bath 2 while controlling the flow rate from the opening of the forehearth twill. The float bath 2 stores a molten metal having a specific gravity higher than that of the glass raw material 70 (in this case, tin 79 as an example). The glass raw material 70 poured into the float bath 2 is placed on the molten tin 79. It flows while floating and spreads on the surface of the tin 79 to a uniform thickness (for example, about 7 mm).

  Next, in a state where the glass raw material 70 is maintained at a predetermined temperature, a plate-shaped glass ribbon 71 having a predetermined thickness and width is slowly stretched in the Y direction by an assist roll (not shown) so that distortion does not occur. To form. Note that the speed at which the glass raw material 70 is poured into the float bath 2 and the speed at which the glass raw material 70 is stretched by the assist roll contributes to determining the thickness of the formed glass ribbon 71.

  Next, in step S120, the plate-like glass ribbon 71 is gradually cooled. Specifically, a lift-out roller (not shown) for pulling out the glass ribbon 71 from the float bath 2 and carrying it into the slow cooling furnace 3 is provided at the subsequent stage of the float bath 2. By driving this lift-out roller, the glass ribbon 71 advances on the conveying means 5 to the downstream side of the float bath 2 while being pulled in the direction of the slow cooling furnace 3. Then, the glass ribbon 71 is carried from the float bath 2 to a slow cooling furnace 3 equipped with a mechanism (not shown) for gradually lowering the temperature of the glass ribbon 71 and is conveyed by a layer roller (not shown) in the slow cooling furnace 3. It is cooled slowly to a temperature range close to room temperature. By slowly cooling, the residual stress inherent in the glass ribbon 71 can be reduced.

  Next, in step S130, the glass ribbon 71 that has passed through the slow cooling furnace 3 is crossed (cut in the Y direction) by the cutting device 4 to produce a glass substrate 72 of a predetermined size.

  Next, in step S140, the glass substrate 72 having a predetermined size cut in step S130 is inspected using the glass substrate inspection apparatus 10 according to the present embodiment. As described above, in the manufacturing process of a glass substrate by the conventional float method, a glass substrate of a predetermined size made from a glass ribbon is taken out every predetermined time to inspect the quality of the glass and the weight is measured. There was a case. In step S140, without performing a sampling inspection, the cross-section of the downstream end of the glass substrate 72 of a predetermined size produced from the glass ribbon 71 is imaged to measure the cross-sectional area, and the glass substrate 72 is measured from the measured cross-sectional area. Calculate the weight.

  Thus, the inspection of the glass substrate 72 is performed after the glass ribbon 71 that has passed through the slow cooling furnace 3 is cut into the glass substrate 72 of a predetermined size by the cutting device 4. That is, the glass substrate inspection apparatus 10 is disposed behind (downstream) the cutting apparatus 4. Details of the glass substrate inspection apparatus 10 will be described later.

  After step S140, in a subsequent process shown in step S150, a mother glass having a size such as so-called G8 or G10 is produced. The post-process shown in Step S150 includes, for example, a process of making a mother glass by further cutting (cutting in the X direction) and crossing (cutting in the Y direction) the glass substrate 72, a process of chamfering the mother glass, It includes a step of polishing the bottom surface of the glass (the surface in contact with tin in the float bath), a step of cleaning the mother glass, a step of packing the mother glass, and the like.

  After step S150, the mother glass is packed and shipped in step S160.

[Inspection equipment for glass substrates]
Next, a glass substrate inspection apparatus will be described. FIG. 3 is a left side view schematically illustrating the glass substrate inspection apparatus according to the present embodiment. FIG. 4 is a front view schematically illustrating the glass substrate inspection apparatus according to this embodiment. FIG. 5 is a left side view schematically illustrating the configuration of the imaging unit according to the present embodiment. FIG. 6 is a perspective view schematically illustrating the configuration of the imaging unit according to the present embodiment.

  Referring to FIGS. 3 and 4, the glass substrate inspection apparatus 10 generally includes illumination means 11 a and 11 b, imaging means 12 a and 12 b, and image processing means 13.

  As shown in FIG. 4, since the glass substrate 72 is stretched in the Y direction by the assist roll from the left and right in the above-described step S110, the cross-sectional shape of the downstream end of the glass substrate 72 is 72a, 72b, And 72c. That is, the cross-sectional shape of the downstream end of the glass substrate 72 is such that the one end 72a and the other end 72b in the Y direction (width direction) are the plate thickness 72c (the thickness between the one end 72a and the other end 72b). Is a thicker cross section than a uniform portion. The width (Y direction) of the one end portion 72a and the other end portion 72b is about 200 mm. Note that, regardless of the position of the glass substrate 72 cut in the Y direction, the cross-sectional shape shown in FIG.

  If an example of the dimension of each part of the glass substrate 72 is given, the maximum plate thickness (Z direction) of the one end part 72a and the other end part 72b is, for example, about 2 mm. The plate thickness (Z direction) of the sampling plate 72c is, for example, about 0.7 mm. The width (Y direction) of the glass substrate 72 is, for example, about 5 m. The length (X direction) of the glass substrate 72 is, for example, about 5 m.

  In the glass substrate inspection apparatus 10, the illumination unit 11 a has a function of irradiating light to the one end portion 72 a and its peripheral portion from an oblique direction on the bottom surface side of the glass substrate 72. The illumination unit 11b has a function of irradiating light to the other end portion 72b and its peripheral portion from an oblique direction on the bottom surface side of the glass substrate 72. The incident angle of each irradiation light from the illumination means 11a and 11b to the cross section at the downstream end of the glass substrate 72 is such that each irradiation light from the illumination means 11a and 11b is totally reflected at the cross section at the downstream end of the glass substrate 72. The angle is set. The incident angle of each irradiation light from the illumination means 11a and 11b to the cross section at the downstream end of the glass substrate 72 can be set to 45 degrees, for example. As the illumination means 11a and 11b, a fluorescent lamp etc. can be used, for example. However, the illumination means 11a and 11b are not limited to fluorescent lamps. Instead of fluorescent lamps, for example, LEDs (Light Emitting Diodes), organic EL elements (Organic Electro-Luminescence elements), halogen lamps, and xenon lamps. Etc. may be used.

  The imaging means 12a has a function of receiving the transmitted light of the light irradiated from the illumination means 11a to the one end portion 72a and its peripheral portion, and imaging the cross section of the downstream end of the glass substrate 72 including the one end portion 72a. Further, the imaging unit 12b receives transmitted light of the light irradiated to the other end portion 72b and its peripheral portion from the illumination unit 11b, and captures a cross section of the downstream end of the glass substrate 72 including the other end portion 72b. Have

  Referring to FIGS. 5 and 6, the imaging means 12a includes a convex cylindrical lens 21a, a concave cylindrical mirror 22a, and a camera 23a. The imaging means 12b includes a convex cylindrical lens 21b, a concave cylindrical mirror 22b, and a camera 23b. The convex cylindrical lens 21a and the concave cylindrical mirror 22a have no curvature in the Y direction. Similarly, the convex cylindrical lens 21b and the concave cylindrical mirror 22b have no curvature in the Y direction. For example, a CCD (Charge Coupled Device) camera or a CMOS (Complimentary Metal Oxide Semiconductor Device) camera can be used as the cameras 23a and 23b.

  The light (diffused light) irradiated from the illumination means 11a to the one end portion 72a and its peripheral portion is totally reflected at the cross section of the downstream end of the glass substrate 72 including the one end portion 72a. On the other hand, the light irradiated from the illuminating means 11a to the portion other than the cross section at the downstream end of the glass substrate 72 reaches the concave cylindrical mirror 22a via the convex cylindrical lens 21a, and the optical path is bent by the concave cylindrical mirror 22a. The light enters an image sensor (not shown) of the camera 23a.

  Similarly, the light (diffused light) emitted from the illumination unit 11b to the other end portion 72b and its peripheral portion is totally reflected at the cross section of the downstream end of the glass substrate 72 including the other end portion 72b. On the other hand, the light irradiated from the illumination means 11b to a portion other than the cross section of the downstream end of the glass substrate 72 reaches the concave cylindrical mirror 22b via the convex cylindrical lens 21b, and the optical path is bent by the concave cylindrical mirror 22b. The light enters the image sensor (not shown) of the camera 23b.

  As a result, an image in which only the cross section of the downstream end of the glass substrate 72 including the one end portion 72a and the cross section of the downstream end of the glass substrate 72 including the other end portion 72b are black can be captured (FIG. 8A and FIG. 8B).

  As described above, the convex cylindrical lens 21a and the concave cylindrical mirror 22a have no curvature in the Y direction. Similarly, the convex cylindrical lens 21b and the concave cylindrical mirror 22b have no curvature in the Y direction. Therefore, the lateral magnification (magnification in the Y direction) from the convex cylindrical lens 21a to the camera 23a is 1, and the vertical magnification (magnification in the Z direction) is a predetermined value larger than 1. Similarly, the lateral magnification (magnification in the Y direction) from the convex cylindrical lens 21b to the camera 23b is 1, and the vertical magnification (magnification in the Z direction) is a predetermined value larger than 1.

  That is, the convex cylindrical lens 21a and the concave cylindrical mirror 22a, and the convex cylindrical lens 21b and the concave cylindrical mirror 22b are optical systems in which the magnification in the thickness direction of the glass substrate 72 is higher than the magnification in the width direction. The reason for setting the vertical magnification to a value larger than the horizontal magnification is to increase the resolution in the Z direction (the thickness direction of the glass substrate 72). Hereinafter, a specific example will be described.

  For example, when the cameras 23a and 23b are each 1 million pixels (1000 pixels × 1000 pixels) and can capture a range of about 300 mm, the measurement length per pixel is 300 mm ÷ 1000 pixels = 0.3 mm. Become. However, as described above, the maximum plate thickness (Z direction) of the one end 72a and the other end 72b of the glass substrate 72 is, for example, about 2 mm. Accordingly, the maximum plate thickness (Z direction) of the one end portion 72a and the other end portion 72b corresponds to only about 7 pixels, respectively, and the plate thickness measurement error becomes large.

  On the other hand, since the width (Y direction) of the glass substrate 72 is, for example, about 5 m, the resolution in the Y direction (the width direction of the glass substrate 72) is sufficient. Therefore, if the vertical magnification is set to a value larger than the horizontal magnification, the resolution in the Z direction (the thickness direction of the glass substrate 72) can be increased. For example, when the vertical magnification is set to 3 times the horizontal magnification, the measurement length per pixel is 300 mm ÷ 1000 pixels ÷ 3 times = 0.1 mm. For example, when the maximum plate thickness (Z direction) of the one end portion 72a and the other end portion 72b of the glass substrate 72 is 2.0 mm, respectively, it corresponds to 20 pixels, so that the plate thickness measurement accuracy can be improved.

  The ratio of the vertical magnification to the horizontal magnification is adjusted by adjusting the curvature and focal length of the convex cylindrical lens 21a and the concave cylindrical mirror 22a, and the curvature and focal length of the convex cylindrical lens 21b and the concave cylindrical mirror 22b. Can be set as appropriate.

  Returning to FIG. 3 and FIG. 4, the image processing means 13 calculates the area of the cross section of the downstream end of the glass substrate based on the image of the cross section of the downstream end of the glass substrate imaged by the imaging means 12 a and 12 b. Have The image processing means 13 further calculates the weight of the glass substrate based on the calculated cross-sectional area of the downstream end of the glass substrate, the length of the known glass substrate, and the specific gravity of the known glass substrate. Have The image processing unit 13 includes a CPU (not shown) and a memory such as a ROM and a RAM. A memory (not shown) of the image processing unit 13 stores a program for calculating the cross-sectional area of the glass substrate 72, and the program is executed by a CPU (not shown), whereby various types of the image processing unit 13 are executed. Function is realized. However, the program for calculating the cross-sectional area of the glass substrate 72 may be stored in a computer-readable recording medium such as an optical recording medium or a magnetic recording medium.

[Glass substrate inspection method]
Next, a glass substrate inspection method will be described. FIG. 7 is a flowchart illustrating the glass substrate inspection method according to this embodiment. That is, FIG. 7 specifically illustrates the contents of step S140 of FIG.

  First, in step S141, the cross section of the downstream end of the glass substrate 72 shown in FIGS. 3 and 4 is imaged. Specifically, the illumination means 11a is turned on at the timing when the cross section of the downstream end of the glass substrate 72 is conveyed to the position of the glass substrate inspection apparatus 10, and the bottom surface side of the glass substrate 72 is provided at one end portion 72a and its peripheral portion. Irradiate light from an oblique direction. Moreover, the illumination means 11b is turned on and light is irradiated to the other end portion 72b and its peripheral portion from an oblique direction on the bottom surface side of the glass substrate 72. Then, the transmitted light of the light irradiated from the illumination means 11a and 11b (light irradiated to a portion other than the cross section at the downstream end of the glass substrate 72) is received by the imaging means 12a and 12b, respectively, and the downstream of the glass substrate 72 is received. An image of a cross section at the side end is taken.

  Since the glass substrate 72 is transported on the transport means 5 at a predetermined speed, the timing at which the cross section of the downstream end of the glass substrate 72 is transported to the position of the glass substrate inspection apparatus 10 is known in advance. be able to. However, a sensor capable of detecting the cross section of the downstream end of the glass substrate 72 is disposed at the position of the glass substrate inspection apparatus 10, and at the timing when the sensor detects the cross section of the downstream end of the glass substrate 72, the cameras 23 a and 23 b A method for imaging may be used. In addition, the glass substrate 72 is picked up at any time interval that is sufficiently shorter than the time interval at which the glass substrate 72 is transported to the position of the glass substrate inspection apparatus 10, and the cross section at the downstream end of the glass substrate 72 is selected from the picked-up images. A method may be used.

  FIG. 8A is a diagram illustrating a cross-sectional image of the downstream end of the glass substrate 72 including the one end portion 72a imaged in step S141. FIG. 8B is a diagram illustrating a cross-sectional image of the downstream end of the glass substrate 72 including the other end 72b imaged in step S141. The light irradiated from the oblique direction to the one end portion 72a and its peripheral portion from the illumination means 11a is totally reflected on the cross section of the downstream end of the glass substrate 72 including the one end portion 72a, and passes through the other portions. As shown in FIG. 8A, the image 73a of the cross section at the downstream end of the glass substrate 72 including the one end 72a is an image that is visually recognized as black. Similarly, the light irradiated from the illumination means 11b to the other end portion 72b and its peripheral portion from an oblique direction is totally reflected on the cross section of the downstream end of the glass substrate 72 including the other end portion 72b, and the other portions. 8B, as shown in FIG. 8B, the image 73b of the cross section at the downstream end of the glass substrate 72 including the other end 72b is an image that is visually recognized as black.

  Next, in step S142, the image processing unit 13 calculates the area of the cross section of the glass substrate 72. As is apparent from FIG. 4, the area of the cross section of the glass substrate 72 is the sum of the areas of the one end portion 72a and the other end portion 72b and the area of the sampling plate portion 72c. Therefore, first, the image processing unit 13 calculates the areas of the one end portion 72a and the other end portion 72b based on the images of the one end portion 72a and the other end portion 72b captured in step S141. The areas of the one end portion 72a and the other end portion 72b can be calculated by counting the number of pixels included in the images 73a and 73b in FIGS. 8A and 8B and multiplying the counted number of pixels by the area of pixels per unit.

  Subsequently, the image processing means 13 calculates the area of the plate-taking part 72c. By the way, in order to calculate the area of the sampling plate 72c, it is necessary to know the width and thickness of the sampling plate 72c, but since the width of the glass substrate 72 is a known value, the glass imaged in step S141. By calculating the widths of the one end portion 72a and the other end portion 72b of the glass substrate 72 from the images of the one end portion 72a and the other end portion 72b of the substrate 72, the width of the plate-taking portion 72c can be known. Moreover, in the manufacturing process of a glass substrate, since the plate | board thickness of the plate-plate part is generally measured with the laser measuring instrument etc., the value can be used.

  However, one or more dedicated imaging means (convex cylindrical lens, concave cylindrical mirror, and camera) are provided in order to calculate the area of the plate portion 72c, and the same as the one end 72a and the other end 72b. You may calculate the area of the plate-drawing part 72c by the method.

  Next, in step S143, the image processing unit 13 calculates the weight of the glass substrate 72. Specifically, since the length and specific gravity of the glass substrate 72 are known values as described above, the image processing means 13 adds the known length and specific gravity of the glass substrate 72 to the cross-sectional area calculated in step S141. By multiplying, the weight of the glass substrate 72 is calculated.

  As described above, according to the present embodiment, the cross section of the downstream end of the glass substrate 72 is imaged to calculate the area, and the weight of the glass substrate 72 is calculated based on the calculated area. As a result, since the weight of the glass substrate 72 can be calculated without performing a sampling inspection, the inspection of the glass substrate 72 can be made efficient. The calculated weight of the glass substrate 72 is fed back to the manufacturing process of the glass substrate 72. For example, if the calculated weight of the glass substrate 72 is larger than the target value, it is determined that the amount of glass raw material dissolved per unit time (pull) is too large, and the pull can be lowered. The glass substrate 72 is transported to the position of the glass substrate inspection apparatus 10 at predetermined time intervals. Each time, the weight of each glass substrate 72 is calculated and fed back to the manufacturing process of the glass substrate 72. .

  The frequency of the sampling inspection that has been performed conventionally is about once every two hours, but by calculating the weight of the glass substrate 72 using the inspection method according to the present embodiment, it is about 200 times per two hours. Measurement is possible (that is, 200 times the efficiency). Therefore, it is possible to greatly increase the frequency of feeding back the calculated weight of the glass substrate 72 to the manufacturing process of the glass substrate 72, and the pull can be controlled more stably than before. As a result, the quality of the glass substrate 72 can be improved.

  Further, in the inspection apparatus for the glass substrate 72, the vertical magnification (magnification in the thickness direction of the glass substrate 72) is set to a value larger than the horizontal magnification (magnification in the width direction of the glass substrate 72). The measurement accuracy of the plate thickness can be improved even for such a glass substrate having an extremely large aspect ratio. As a result, the calculation accuracy of the weight of the glass substrate 72 can be improved.

  The preferred embodiment has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various modifications and replacements are made to the above-described embodiment without departing from the scope described in the claims. Can be added.

  For example, in the above-described embodiment, the example in which the illumination units 11 a and 11 b are arranged on the bottom surface side of the glass substrate 72 and the imaging units 12 a and 12 b are arranged on the upper surface side of the glass substrate 72 has been shown. However, the illumination means 11a and 11b may be arranged on the upper surface side of the glass substrate 72, and the imaging means 12a and 12b may be arranged on the bottom surface side of the glass substrate 72.

DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Float bath 3 Slow cooling furnace 4 Cutting device 5 Conveying means 10 Glass substrate inspection apparatus 11a, 11b Illuminating means 12a, 12b Imaging means 13 Image processing means 21a, 21b Convex cylindrical lenses 22a, 22b Concave cylindrical mirrors 23a, 23b Camera 70 Glass raw material 71 Glass ribbon 72 Glass substrate 72a One end 72b The other end 72c Laying plate 73a, 73b Image 79 Tin

Claims (14)

Illumination means for irradiating light from an oblique direction to the cross section of the transparent substrate and its peripheral part;
An imaging unit that receives transmitted light of the light emitted from the illumination unit and captures an image of the cross section;
An inspection apparatus for a transparent substrate, comprising: an image processing unit that calculates an area of the cross section based on an image of the cross section captured by the imaging unit.   The transparent substrate inspection apparatus according to claim 1, wherein the imaging unit includes an optical system in which a magnification in the thickness direction of the transparent substrate is higher than a magnification in the width direction.   The transparent substrate inspection apparatus according to claim 1, wherein at least one set of the illumination unit and the imaging unit is provided at a position where images of both end portions of a cross section of the transparent substrate can be captured.   4. The image processing unit according to claim 1, further comprising calculating a weight of the transparent substrate based on an area of the cross section, a length of the transparent substrate, and a specific gravity of the transparent substrate. 5. Inspection equipment for transparent substrates.   5. The transparent substrate inspection apparatus according to claim 1, wherein light emitted from the illumination unit to the cross section of the transparent substrate is totally reflected by the cross section of the transparent substrate. 6.   The transparent substrate inspection apparatus according to claim 1, wherein the transparent substrate is a glass substrate. An illumination process for irradiating light from an oblique direction to the cross section of the transparent substrate and its peripheral part;
An imaging step of receiving transmitted light of the light irradiated in the illumination step and capturing an image of the cross section;
An image processing step of calculating an area of the cross section based on the image of the cross section taken in the imaging step.   The transparent substrate inspection method according to claim 7, wherein in the imaging step, an image of the cross section is captured by setting a magnification in the thickness direction of the transparent substrate higher than a magnification in the width direction.   The method for inspecting a transparent substrate according to claim 7 or 8, wherein in the illuminating step and the imaging step, at least images of both end portions of a cross section of the transparent substrate are taken.   The weight of the transparent substrate is further calculated in the image processing step based on the area of the cross section, the length of the transparent substrate, and the specific gravity of the transparent substrate. Inspection method for transparent substrates.   The method for inspecting a transparent substrate according to any one of claims 7 to 10, wherein the light applied to the cross section of the transparent substrate in the illumination step is totally reflected by the cross section of the transparent substrate.   The method for inspecting a transparent substrate according to claim 7, wherein the transparent substrate is a glass substrate.   The manufacturing method of the glass substrate which has the test | inspection process which test | inspects the said glass substrate with the inspection method of the transparent substrate of Claim 12. A molding step of melting the crow raw material to be the glass substrate and molding it into a plate-shaped glass ribbon;
A slow cooling step of slowly cooling the glass ribbon;
Cutting the glass ribbon to produce the glass substrate, and
The method for manufacturing a glass substrate according to claim 13, wherein in the inspection step, a cross section of the glass substrate cut in the cutting step is inspected.

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