Method and apparatus for measuring transparent materials, and method for manufacturing glass plates.

Abstract

This transparent body measuring method includes: a preparation step for placing a transparent body on a placement platform provided with an opening portion; and a measurement step for measuring a property of the transparent body by shining a laser beam from a measuring device through the opening portion onto a glass substrate, while causing the measuring device to move relative to the placement platform in a prescribed measuring direction without stopping.

Description

Technical Field

[0001] The present invention relates to a measuring method and a measuring machine capable of measuring the characteristics of a transparent body including a glass plate, and a method for manufacturing a glass plate.

Background Art

[0002] In recent years, in panel displays such as liquid crystal display devices and organic EL display devices, enlargement has been promoted. In such displays, color unevenness of an image becomes a problem. Since this color unevenness of the image is caused by the distortion of the glass substrate used for the display, it is necessary to measure the distortion during the manufacture of the glass substrate.

[0003] For example, Patent Document 1 discloses a measuring machine (glass substrate distortion measuring device) including a gantry, a mounting table held by the gantry on which a glass substrate is placed, and a distortion measuring unit that irradiates a laser beam onto the glass substrate supported horizontally by the mounting table to measure distortion (see Claim 6 of the same document).

[0004] In this measuring machine, the gantry has a slide mechanism for moving the mounting table in the horizontal direction. The mounting table has a plurality of openings for irradiating the glass substrate with the laser beam emitted from the distortion measuring unit. The distortion measuring unit includes a laser beam irradiation unit movable in a direction orthogonal to the moving direction of the mounting table, and a laser beam light receiving unit arranged to face the laser beam irradiation unit and movable in the same direction as the laser beam irradiation unit (see Paragraphs 0033, 0041, 0053, FIGS. 1 to 4 of the same document).

[0005] [[ID=(24)]]In the method of measuring the distortion of the glass substrate using this measuring machine, the distortion measuring unit irradiates the horizontal glass substrate supported by the mounting table with a laser beam while changing its position along a predetermined direction. Specifically, the laser beam irradiation unit and the laser beam light receiving unit repeatedly perform operations such as moving, stopping, irradiating, and receiving the laser beam with respect to the measurement points of the glass substrate set within the range of each opening of the mounting table (see Paragraphs 0054, 0064 of the same document).

Prior Art Documents

[0006] [Patent Document 1] International Publication No. 2017 / 221825 [Overview of the project] [Problems that the invention aims to solve]

[0007] In conventional strain measurement methods, the strain measurement unit stops each time it moves to a measurement point on the glass substrate, which is set within the range of each opening in the mounting table, to measure the strain. With such a measurement method, there was a risk that the measurement time would become prolonged for larger glass substrates.

[0008] This invention has been made in view of the above circumstances, and its technical objective is to efficiently measure the properties of transparent materials, including glass plates. [Means for solving the problem]

[0009] (1) The present invention is for solving the above problems and is a method for measuring the properties of a transparent body including a glass plate using a laser-transmitting measuring device, comprising: a preparation step of placing the transparent body on a mounting table having an opening; and a measurement step of measuring the properties of the transparent body by irradiating the transparent body with laser light from the measuring device through the opening while moving the measuring device relative to the mounting table along a predetermined measurement direction without stopping the device.

[0010] With this configuration, during the measurement process, the properties of the transparent material can be measured while moving the measuring device relative to the mounting table along a predetermined measurement direction without stopping the device. This reduces the measurement time compared to the conventional method of stopping the measuring device during measurement. As a result, it becomes possible to efficiently measure the properties of the glass substrate.

[0011] (2) In the measurement method of (1) above, the measuring device is a birefringence measuring device, in the preparation step the transparent body is placed horizontally, and in the measurement step the characteristic of the transparent body measured by the birefringence measuring device may be the distortion of the transparent body.

[0012] (3) In the measurement method of (2) above, the transparent body may be a glass substrate for a display.

[0013] (4) In the measurement method of (2) or (3) above, the birefringence measuring device may include a plurality of birefringence measuring devices, and the plurality of birefringence measuring devices may be arranged at intervals in a direction perpendicular to the measurement direction. The distortion of the transparent material can be measured more efficiently by using a plurality of birefringence measuring devices.

[0014] (5) In any of the measurement methods described in (1) to (4) above, the opening of the mounting stand described above may be configured in a rectangular shape. This makes it possible to secure the largest possible opening area of ​​the opening formed in the mounting stand. Therefore, by securing a wide range over which laser light can be irradiated onto the transparent object, it becomes possible to acquire more measurement data.

[0015] (6) In addition, in any of the measurement methods described in (1) to (5) above, the opening of the stand described above may be configured in a rectangular shape, and the long side of the opening may be formed to align with the measurement direction. With such a configuration, a wide measurement range can be secured on the glass substrate along the measurement direction.

[0016] (7) In addition, in any of the measurement methods described in (1) to (6) above, the opening of the stand described above includes a plurality of openings arranged in a straight line, and in the measurement step, the measuring device may move in a straight line along the direction in which the plurality of openings are arranged. With this configuration, by moving the measuring device in a straight line along the direction in which the plurality of openings are arranged, laser light can be efficiently irradiated onto the transparent body through each opening located on this straight line.

[0017] (8) In the measurement method of (7) above, the measurement step comprises a data detection step of acquiring detection data relating to the laser light transmitted through the glass substrate, and a calculation processing step of calculating the strain using a control device based on the detection data detected in the data detection step, the measurement device comprises a laser light irradiation unit that emits the laser light and a laser light receiving unit that receives the laser light, the stand described above comprises a frame that separates the plurality of openings, in the measurement step, the measurement device performs multiple strain measurements on the transparent body while moving relative to the stand described above, the width dimension of the frame located between two adjacent openings is set to be smaller than the distance the laser light moves due to the movement of the measurement device during the execution of the calculation processing step relating to one strain measurement, and in the measurement step, the laser light emitted from the laser light irradiation unit may pass through the frame during the execution of the calculation processing step.

[0018] With this configuration, during the execution of the calculation process, the laser light emitted from the measuring device passes through the frame, allowing for a greater number of strain measurements on the glass substrate within the aperture range. This makes it possible to efficiently acquire more measurement data.

[0019] (9) In any of the measurement methods described in (1) to (8) above, the relative movement of the measuring device with respect to the aforementioned stand may be the movement of the measuring device itself.

[0020] (10) In addition, in any of the measurement methods described in (1) to (8) above, the relative movement of the measuring device with respect to the aforementioned stand may be the movement of the aforementioned stand.

[0021] (11) The present invention is for solving the above problems, and is a method for manufacturing a glass plate, comprising: a forming step of forming a glass ribbon from molten glass; a slow cooling step of slowly cooling the glass ribbon; a cutting step of cutting the glass ribbon that has undergone the slow cooling step into a glass plate of a predetermined size; and an inspection step of performing the measurement method of any one of the above (1) to (9) on the glass plate.

[0022] According to such a configuration, by efficiently measuring the characteristics of the glass substrate in the inspection step, it is possible to promptly feedback the change in the characteristics of the glass plate to the slow cooling step.

[0023] (12) The present invention is for solving the above problems, and is a measuring machine for measuring the characteristics of a transparent body including a glass plate, comprising: a mounting table for horizontally supporting the transparent body; and a laser transmission type measuring device that relatively moves with respect to the mounting table. The mounting table is provided with an opening for irradiating the glass substrate with the laser light emitted from the measuring device, and measures the characteristics of the transparent body while relatively moving the mounting table along a predetermined measurement direction without stopping the measuring device.

[0024] According to such a configuration, by measuring the characteristics of the transparent body while relatively moving the measuring device along a predetermined measurement direction without stopping it with respect to the mounting table, the measurement time can be shortened as compared with the case of measuring by stopping the measuring device as in the prior art. Thereby, it becomes possible to efficiently measure the characteristics of the glass substrate.

[0025] (13) In the measuring machine of the above (12), the opening of the mounting table may be configured in a rectangular shape. Thereby, it is possible to ensure the opening area of the opening formed in the mounting table to be as large as possible.

Effect of the Invention

[0026] According to the present invention, it is possible to efficiently measure the characteristics of a transparent body including a glass plate.

Brief Description of the Drawings

[0027] [Figure 1] It is a side view of the measuring machine. [Figure 2] It is a side view of the measuring machine. [Figure 3] It is a plan view of the measuring machine. [Figure 4] It is a front view of the measuring machine. [Figure 5] It is a plan view showing a method for measuring a transparent body. [Figure 6] It is a plan view showing a method for measuring a transparent body. [Figure 7] It is a plan view showing a method for measuring a transparent body. [Figure 8] It is a plan view showing a method for measuring a transparent body. [Figure 9] It is a plan view showing another example of the mounting table in the measuring machine.

Modes for Carrying Out the Invention

[0028] Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. FIGS. 1 to 9 show an embodiment of a method for measuring a transparent body and a measuring machine according to the present invention. In the orthogonal coordinate system composed of the three axes X, Y, and Z shown in FIGS. 1 to 9, the X-axis direction and the Y-axis direction indicate the horizontal direction, and the Z-axis direction indicates the vertical direction (up and down direction).

[0029] The measuring method and measuring machine according to the present invention are for measuring the characteristics of a transparent body including a glass plate. Examples of the characteristics of the transparent body include, for example, thickness, surface roughness, undulation, distortion, etc. Examples of the transparent body include, in addition to a transparent glass plate, a glass plate laminate formed by laminating a plurality of transparent glass plates via a transparent adhesive, a glass resin laminate formed by laminating a transparent glass plate and a transparent resin via a transparent adhesive, and the like.

[0030] In this embodiment, the measurement of distortion in a transparent glass substrate for a display is described as an example. The glass substrate is formed in a square or rectangular shape, for example, with a side length of 2000 to 3400 mm. The thickness of the glass substrate is, for example, 0.1 to 1.2 mm. The shape, dimensions, thickness, etc., of the glass substrate are not particularly limited and can be appropriately changed depending on the application.

[0031] As shown in Figures 1 to 4, the measuring machine 1 comprises a stand 2, a mounting table 3 capable of horizontally supporting a glass substrate G, a laser-transmitting measuring device 4 that can move relative to the mounting table 3 along a predetermined measurement direction, and a control device 5 that controls the operation of the mounting table 3 and the measuring device 4.

[0032] The support frame 2 is a platform for holding the mounting base 3 in an inclined or horizontal position, and is installed on the floor. Here, "horizontal position" is not limited to a perfectly horizontal position (inclination angle = 0°), but also includes a nearly horizontal position, for example, a position that appears horizontal visually. Specifically, "horizontal position" also includes a position where the mounting base 3 is slightly inclined, and the inclination angle with respect to the horizontal direction (Y-axis direction) is in the range of -10° or more and less than 0° or greater than 0° and less than or equal to 10°.

[0033] As shown in Figures 1 to 3, the frame 2 is configured in an elongated shape along the Y-axis. The frame 2 is equipped with a sliding mechanism 6 that moves the mounting platform 3 along its longitudinal direction. The sliding mechanism 6 is positioned at both ends of the mounting platform 3 in the width direction (X-axis direction).

[0034] Each slide mechanism 6 includes a pivot shaft 7 that rotatably supports the middle portion of the mounting base 3, a horizontal drive device (not shown) that moves the mounting base 3 along the horizontal direction, and a rotation drive device (not shown) that rotates the mounting base 3 around the pivot shaft 7.

[0035] The horizontal drive device is composed of a linear motion mechanism that includes, for example, an LM guide (registered trademark), a ball screw mechanism, and a motor. By operating the horizontal drive device, the mounting platform 3, which is in a horizontal position, can be moved along the longitudinal direction (Y-axis direction) of the frame 2.

[0036] The rotation drive device is composed of, for example, an actuator such as an air cylinder or a motor. The rotation drive device can change the mounting base 3 between an inclined state having an angle of 70 to 80 degrees with respect to the horizontal direction (Y-axis direction) and a horizontal state via the rotation shaft 7.

[0037] As shown in Figure 3, the mounting base 3 comprises a stage section 8, a receiving section 9, and positioning sections 10a and 10b.

[0038] The stage section 8 is composed of a plate-shaped member made of metal (for example, aluminum). The stage section 8 functions as a surface plate to maintain the flatness of the glass substrate G to the desired accuracy when measuring strain.

[0039] The stage section 8 has a mounting surface configured as a flat surface. The mounting surface includes a plurality of openings 11 and frame sections 12a and 12b that separate each opening 11.

[0040] Each opening 11 is configured, for example, in a square shape, but is not limited to this shape. Each opening 11 is for irradiating the glass substrate G with laser light that is irradiated from below to above the mounting stage 3 during strain measurement by the measuring device 4. The multiple openings 11 are arranged linearly at predetermined intervals along the X-axis and Y-axis directions of the stage section 8.

[0041] As shown in Figure 3, the frame portions 12a and 12b support one side of the glass substrate G when the glass substrate G is placed on the stage portion 8. Each frame portion 12a and 12b has a predetermined length and width dimension and is configured in a straight line.

[0042] The frame sections 12a and 12b include a first frame section 12a aligned in the X-axis direction and a second frame section 12b aligned in the Y-axis direction. The opening 11 is rectangular in shape because the first frame section 12a and the second frame section 12b are formed to be perpendicular to each other. Furthermore, the mounting surface of the stage section 8 is configured in a grid pattern because multiple first frame sections 12a and second frame sections 12b are connected to each other perpendicularly.

[0043] As shown in Figures 1 to 3, the support portion 9 is provided on one end of the stage portion 8 and is configured to be elongated along the width direction of the mounting base 3. The support portion 9 supports one end (lower end) of the glass substrate G when the mounting base 3 is in an inclined state. The support portion 9 also functions as a positioning portion that contacts one end of the glass substrate G when the mounting base 3 is in a horizontal state. The support portion 9 is configured to be repositionable so that it can be positioned according to the size of the glass substrate G.

[0044] As shown in Figure 3, the positioning units 10a and 10b include a pair of first positioning units 10a that position each end of the glass substrate G in the X-axis direction when the mounting base 3 is in a horizontal position, and a second positioning unit 10b that positions the end of the glass substrate G in the Y-axis direction (the end opposite to the end that contacts the receiving unit 9). Each positioning unit 10a and 10b is configured to be repositionable so that positioning can be performed according to the size of the glass substrate G.

[0045] The measuring device 4 is positioned midway along the longitudinal direction of the frame 2. The measuring device 4 comprises a laser beam irradiation unit 13, a laser beam receiving unit 14, a support member 15 that supports the laser beam receiving unit 14, a drive device (not shown) that drives the laser beam irradiation unit 13, and a drive device (not shown) that drives the laser beam receiving unit 14.

[0046] The laser beam irradiation unit 13 is located at the bottom of the frame 2 and is configured to emit laser light upward from below the mounting base 3 toward the opening 11. The laser beam irradiation unit 13 is also configured to move along the X-axis direction by a drive device.

[0047] The laser light receiving unit 14 is positioned above the laser light irradiating unit 13 so as to face the laser light irradiating unit 13 in the vertical direction (Z-axis direction). The laser light receiving unit 14 is configured to move along the X-axis direction by a drive device.

[0048] Due to the positional relationship between the laser beam irradiation unit 13 and the laser beam receiving unit 14 as described above, when the mounting base 3 is in a horizontal position, it will be positioned between the laser beam irradiation unit 13 and the laser beam receiving unit 14 in the vertical direction (Z-axis direction).

[0049] The support member 15 supports the laser light receiving unit 14 so that it can move in the X-axis direction. The support member 15 also supports the drive device that drives the laser light receiving unit 14.

[0050] The drive unit for the laser beam irradiation unit 13 and the drive unit for the laser beam receiving unit 14 are configured by a linear motion mechanism that includes, for example, an LM guide (registered trademark), a ball screw mechanism, a motor, etc.

[0051] The measuring device 4 is not limited to the above configuration; it may be configured to move the laser light irradiation unit 13 and the laser light receiving unit 14 in the X-axis and Y-axis directions by combining multiple drive units. Alternatively, the measuring device 4 may be configured by attaching the laser light irradiation unit 13 and the laser light receiving unit 14 to a robot arm (drive unit). This makes it possible for the measuring device 4 to move the laser light irradiation unit 13 and the laser light receiving unit 14 in three dimensions.

[0052] As the measuring device 4, a birefringence measuring device is preferably used, for example, one that uses a common path interferometer based on the optical heterodyne method and Fourier analysis to measure the amount of birefringence of the glass substrate G. This birefringence measuring device can measure the magnitude of retardation (phase difference due to birefringence) and the azimuth angle of retardation in order to evaluate the degree of strain of the glass substrate G. Note that a larger retardation indicates greater strain.

[0053] The control device 5 controls the operation of the drive devices (horizontal drive device, rotational drive device) of the slide mechanism 6 of the frame 2, the operation of the drive devices of the measuring device 4, and the operation of the measuring device 4 (laser light irradiation unit 13 and laser light receiving unit 14) related to strain measurement.

[0054] The control device 5 is, for example, a personal computer (PC) equipped with a processing unit such as a CPU, a storage device such as memory, and a display device such as a display. The control device 5 can output the measurement results of the glass substrate G to the display device. The control device 5 can also store the measurement results of the glass substrate G and other data in its storage device.

[0055] The following describes a method for measuring strain, a characteristic of the glass substrate G, using the measuring instrument 1 with the above configuration, and a method for manufacturing the glass substrate G. This measurement method is performed, for example, in the manufacturing process of the glass substrate G to measure the strain of the glass substrate G and to feed back information regarding the quality of the glass substrate G to the manufacturing process based on the measurement results.

[0056] The method for manufacturing the glass substrate G comprises a molding step of stretching molten glass in a predetermined direction to form a plate-shaped glass ribbon, a slow cooling step of slowly cooling the glass ribbon formed in the molding step, a cutting step of cutting the glass ribbon cooled in the slow cooling step to a predetermined size to obtain a glass plate, and an inspection step of performing the measurement method on the glass plate obtained in the cutting step.

[0057] In the annealing process, the glass ribbon flows down through the annealing furnace, which suppresses the occurrence of unintended thermal distortion in the glass ribbon. The annealing furnace is equipped with multiple heaters in the direction of the glass ribbon's drawing and width, and is adjusted to a predetermined temperature gradient. By controlling the output of the heaters in the annealing furnace and adjusting the temperature gradient within the furnace based on the distortion of the glass plate measured by this measurement method, the distortion of the glass plate can be reduced.

[0058] This measurement method comprises a preparation step of placing the glass substrate G on the mounting table 3, and a measurement step of measuring the strain of the glass substrate G placed on the mounting table 3.

[0059] As shown in Figure 1, in the preparation step, the glass substrate G is placed on a mounting table 3 that is waiting in an inclined position at one end of the frame 2. Specifically, for example, an operator holds the glass substrate G using a suction holder such as a vacuum lift, and then places the glass substrate G on the mounting table 3. As a result, the glass substrate G is supported in an inclined position with its lower end in contact with the receiving portion 9 of the mounting table 3.

[0060] Subsequently, as shown in Figure 2, the control device 5 activates the rotation drive device of the slide mechanism 6 to rotate the mounting base 3 around the rotation axis 7. As a result, the orientation of the mounting base 3 changes from an inclined state to a horizontal state, and the glass substrate G is supported horizontally by this mounting base 3.

[0061] In the measurement process, the measuring machine 1 measures the glass substrate G by moving the mounting table 3 and the measuring device 4 relative to each other under the control of the control device 5. This relative movement of the mounting table 3 and the measuring device 4 includes a first movement mode in which the laser light irradiation unit 13 and the laser light receiving unit 14 are moved while the mounting table 3 is stationary, and a second movement mode in which the mounting table 3 is moved while the laser light irradiation unit 13 and the laser light receiving unit 14 are stationary.

[0062] The measurement process based on the first and second movement modes will be described below with reference to Figures 5 to 7. Figures 5 to 7 are plan views showing the glass substrate G placed on the stage portion 8 of the mounting table 3 in a horizontal state. Figures 5 and 6 show the measurement process based on the first movement mode, and Figure 7 shows the measurement process based on the second movement mode.

[0063] In the examples shown in Figures 5 and 6, we will describe the case in which the glass substrate G is measured with respect to the openings 11 belonging to the first row M1, second row M2, and third row M3, which are arranged along the X-axis direction (measurement direction X1, X2), among the multiple openings 11 formed in the stage portion 8 of the mounting table 3.

[0064] Under the control of the control device 5, the laser beam irradiation unit 13 and the laser beam receiving unit 14 move along the measurement direction X1 from the position corresponding to the first opening 11S in the first row M1 to the position corresponding to the last opening 11E. In this case, the laser beam irradiation unit 13 and the laser beam receiving unit 14 move at a constant speed (continuously) without stopping until they reach the position corresponding to the last opening 11E in the first row M1. While the laser beam irradiation unit 13 and the laser beam receiving unit 14 are moving, the mounting table 3 remains stationary (the same applies hereafter to the measurement of the second row M2 and the third row M3).

[0065] As the laser beam irradiation unit 13 and the laser beam receiving unit 14 move as described above, the laser beam emitted from the laser beam irradiation unit 13 moves along the measurement direction X1, passing through the openings 11S, 11, 11E in the first row M1 and the second frame unit 12b, as indicated by arrow A1 in the plan view shown in Figure 5. As a result, the laser beam moves relative to the glass substrate G and linearly. The moving speed of the laser beam, i.e., the moving speed of the laser beam irradiation unit 13 and the laser beam receiving unit 14, is, for example, 10 to 1000 mm / s, preferably 50 to 200 mm / s.

[0066] As described above, the laser beam moves and irradiates the glass substrate G through each aperture 11. After passing through the glass substrate G, the laser beam irradiated through the aperture 11 reaches the laser beam receiving unit 14. The control device 5 calculates the strain of the glass substrate G based on the detection data regarding the amount of birefringence of the laser beam detected by the laser beam receiving unit 14.

[0067] Once the measurement of the glass substrate G corresponding to all the apertures 11 belonging to the first row M1 is completed, the measurement of the glass substrate G corresponding to the apertures 11 belonging to the second row M2 is performed. When the laser beam reaches the last aperture 11E of the first row M1, the control device 5 stops the laser beam irradiation unit 13 and the laser beam receiving unit 14, and moves the mounting table 3 along the direction Y2 perpendicular to the measurement direction X1.

[0068] As a result, the laser beam moves linearly relative to the glass substrate G from the position of the last opening 11E in the first row M1 to the position of the first opening 11S in the second row M2, as indicated by arrow A2. At this time, the laser beam passes through the first frame portion 12a that separates the last opening 11E in the first row M1 and the first opening 11S in the second row M2.

[0069] Subsequently, the control device 5 stops the mounting table 3 and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 along the measurement direction X2. As a result, the laser beam moves relative to the glass substrate G and linearly from the position of the first opening 11S in the second row M2 to the position of the last opening 11E, as indicated by arrow A3.

[0070] This movement causes laser light to irradiate the glass substrate G through each opening 11, and the laser light that has passed through the glass substrate G is received by the laser light receiving unit 14. The control device 5 calculates the strain of the glass substrate G based on the detection data regarding the amount of birefringence of the laser light detected by the laser light receiving unit 14, similar to the measurement at the opening 11 of the first row M1.

[0071] Once the measurement of the glass substrate G corresponding to all the apertures 11 belonging to the second row M2 is completed, the measurement of the glass substrate G corresponding to the apertures 11 belonging to the third row M3 is performed. When the laser beam reaches the last aperture 11E of the second row M2, the control device 5 stops the laser beam irradiation unit 13 and the laser beam receiving unit 14, and moves the mounting table 3 along the direction Y2 which is perpendicular to the measurement direction X2.

[0072] As a result, the laser beam moves linearly relative to the glass substrate G from the position of the last opening 11E in the second row M2 to the position of the first opening 11S in the third row M3, as indicated by arrow A4. At this time, the laser beam passes through the first frame portion 12a that separates the last opening 11E in the second row M2 and the first opening 11S in the third row M3.

[0073] Subsequently, the control device 5 stops the mounting table 3 and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 along the measurement direction X1. As a result, the laser beam moves relative to the glass substrate G and linearly from the position of the first opening 11S in the third row M3 to the position of the last opening 11E, as indicated by arrow A5. During this movement of the laser beam, strain measurements are performed in the same manner as the measurements of the glass substrate G corresponding to the openings 11 in the first row M1 and the second row M2. Subsequently, by repeating the above operations from the fourth row to the last row, the measurement of the entire glass substrate G is completed.

[0074] In the above measurement process, while the laser beam passes through one aperture 11 along the measurement directions X1 and X2, one or more strain measurements can be performed on the glass substrate G within the range of the aperture 11.

[0075] The measurement process comprises a data detection step in which the laser light receiving unit 14 acquires detection data regarding the amount of birefringence of the laser light in a single strain measurement, and a calculation processing step in which the control device calculates the strain based on the detection data detected in the data detection step. The time required for one strain measurement is the sum of the data detection time for the data detection step and the calculation processing time for the calculation processing step. In this embodiment, it is desirable that the time required for each strain measurement by the measuring device 4 is 0.1 seconds or less.

[0076] In this embodiment, by alternately repeating the data detection step and the calculation processing step in the measurement process, multiple strain measurements can be performed on the glass substrate G within the range of a single aperture 11. The case in which this measurement is performed will be described below with reference to Figure 6. In Figure 6, a magnified view is shown of the state in which the laser beam moves in the direction indicated by arrow A5 to the aperture 11 belonging to the third row M3 exemplified in Figure 5.

[0077] The measuring device 4 is configured to perform three measurements at one opening 11 belonging to the third row M3. The glass substrate G placed on the stage 8 has three measurement areas within the range of one opening 11: the first measurement area MA1, the second measurement area MA2, and the third measurement area MA3. Each of the measurement areas MA1 to MA3 is configured in a straight line along the measurement direction X1.

[0078] The laser beam irradiation unit 13 moves along the measurement direction X1 together with the laser beam receiving unit 14, irradiating the first measurement area MA1 with laser beam. The laser beam passes through this first measurement area MA1 and reaches the laser beam receiving unit 14.

[0079] The time it takes for the laser beam to irradiate the first measurement area MA1 while moving corresponds to the data detection time in the data detection process. This laser beam travel time (data detection time) is, for example, 0.05 seconds. During this time, the laser beam moves by the length of the first measurement area MA1, that is, the distance indicated by the symbol D1 in Figure 6 (first travel distance).

[0080] The control device 5 performs a calculation process while the laser beam moves from the end of the first measurement area MA1 to the beginning of the second measurement area MA2. That is, the control device 5 calculates the strain in the first measurement area MA1 based on the detection data of the laser beam detected through the laser beam receiving unit 14. The time it takes for the laser beam to move from the first measurement area MA1 to the second measurement area MA2 corresponds to the calculation processing time in the calculation process. In this case, the laser beam's travel time (calculation processing time) is, for example, 0.05 seconds. During this time, the laser beam moves a distance indicated by the symbol D2 in Figure 6 (second travel distance). In this embodiment, the second travel distance D2 is equal to the first travel distance D1, but these distances D1 and D2 may be different.

[0081] The time required for measuring strain in the first measurement area MA1, i.e., the first measurement (measurement time), is the sum of the data detection time and the calculation processing time, for example, 0.1 seconds. The distance traveled by the laser beam during the first measurement (the relative distance traveled by the measuring device 4) is the sum of the first travel distance D1 and the second travel distance D2 (D1+D2). In other words, the measurement process in this embodiment involves measuring the glass substrate G while irradiating each measurement area, which is set at an equal pitch (D2), with the data detection process and calculation processing process performed while the laser beam travels this distance (D1+D2) forming one cycle. The distance traveled by the laser beam (D1+D2) is, for example, 5 to 10 mm, but is not limited to this range.

[0082] Once the first measurement is completed, the second measurement is performed. During the second measurement, as the measuring device 4 moves continuously, the laser light emitted from the laser light irradiation unit 13 is irradiated onto the second measurement area MA2. During this time, the laser light that has passed through the second measurement area MA2 is received by the laser light receiving unit 14, and detection data related to the laser light is detected (data detection process).

[0083] Subsequently, while the laser beam moves from the end of the second measurement area MA2 to the beginning of the third measurement area MA3, the control device 5 calculates the strain related to the second measurement area MA2 (calculation processing step). The data detection time and strain calculation processing time in the second measurement are the same as in the first measurement. In the second measurement, the distance traveled by the measuring device 4 and the laser beam is the same as the travel distance (D1 + D2) in the first measurement.

[0084] The third measurement is performed in the same manner as the first and second measurements. The measuring device 4 moves along the measurement direction X1 and irradiates the third measurement area MA3 with laser light. During this time, the laser light that has passed through the third measurement area MA3 is received by the laser light receiving unit 14, and detection data related to the laser light is detected (data detection step). The control device 5 calculates the strain related to the third measurement area MA3 based on this detection data (calculation processing step).

[0085] The opening 11 has an opening area that allows for multiple measurements by the measuring device 4, as described above. That is, the distance W1 between the pair of second frame portions 12b that divide one opening 11 is greater than the distance (D1+D2) that the laser beam and the measuring device 4 travel in a single measurement (W1>(D1+D2)).

[0086] In the last of the multiple measurements performed on the glass substrate G within the range of a single aperture 11 (the third measurement in the example above), it is desirable that the laser beam passes through the second frame portion 12b separating the aperture 11 from the next aperture 11 while the control device 5 is executing the calculation process. This allows the measurement of the glass substrate G to begin immediately after the laser beam reaches the next aperture 11. Therefore, it is possible to ensure as many strain measurements as possible within the range of a single aperture 11.

[0087] In this case, as shown in Figure 6, it is preferable that the width dimension W2 of the second frame portion 12b located between two adjacent openings 11 in the measurement direction X1 be set to be smaller than the second movement distance D2 during which the laser beam and the measuring device 4 move within the calculation processing time in the calculation processing step (W2 <D2)。

[0088] When the calculation process is complete, the control device 5 outputs the measurement result (strain calculation result) of the glass substrate G to the display device. The control device 5 also saves the measurement result data of the glass substrate G to the storage device. In addition, the control device 5 can compare the measurement result with a pre-set standard value (regression magnitude and retardation azimuth angle), which is an index for evaluating strain, and make a judgment on the quality of the strain in the glass substrate G. The control device 5 displays this judgment result on the display device.

[0089] Figure 7 shows the measurement process according to the second movement mode. In this example, we will describe the case in which the glass substrate G is measured according to the openings 11 belonging to the first row N1, second row N2, and third row N3, which are arranged along the Y axis direction (measurement direction Y1, Y2), among the multiple openings 11 formed in the stage portion 8 of the mounting table 3.

[0090] The control device 5 positions the laser beam irradiation unit 13 and the laser beam receiving unit 14 of the measuring device 4 at positions corresponding to the first opening 11S of the first row N1. Then, with the laser beam irradiation unit 13 and the laser beam receiving unit 14 stopped, the control device 5 emits laser light from the laser beam irradiation unit 13.

[0091] Subsequently, the control device 5 moves the mounting platform 3 linearly at a constant velocity along the measurement direction Y1 relative to the stationary laser beam irradiation unit 13 and laser beam receiving unit 14. As a result, the laser beam moves linearly relative to the glass substrate G from the position of the first opening 11S in the first row N1 to the position of the last opening 11E, as indicated by arrow B1.

[0092] The measuring device 4 and the control device 5 move the mounting table 3 in the Y1 direction, thereby moving the laser beam relative to the mounting table 3, and repeatedly perform the data detection process and the calculation processing process, similar to the example of the first movement mode shown in Figures 5 and 6.

[0093] When the measurement of the glass substrate G within the range of the last opening 11E in the first row N1 is completed, the control device 5 stops the mounting table 3 and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 along the direction X1 perpendicular to the measurement direction Y1. As a result, the laser beam moves relative to the glass substrate G and linearly, as indicated by arrow B2, from the position of the last opening 11E in the first row N1 to the position of the first opening 11S in the second row N2.

[0094] Subsequently, the control device 5 stops the laser beam irradiation unit 13 and the laser beam receiving unit 14, and moves the mounting table 3 along the measurement direction Y2. As a result, the laser beam moves relative to the glass substrate G and linearly from the position of the first opening 11S in the second row N2 to the position of the last opening 11E, as indicated by arrow B3.

[0095] When the measurement of the glass substrate G within the range of the last opening 11E in the second row N2 is completed, the control device 5 stops the mounting table 3 and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 along the direction X1 perpendicular to the measurement direction Y2. As a result, the laser beam moves relative to the glass substrate G and linearly, as indicated by arrow B4, from the position of the last opening 11E in the second row N2 to the position of the first opening 11S in the third row N3.

[0096] Subsequently, the control device 5 stops the laser beam irradiation unit 13 and the laser beam receiving unit 14, and moves the mounting table 3 along the measurement direction Y1. As a result, the laser beam moves relative to the glass substrate G and linearly from the position of the first opening 11S in the third row N3 to the position of the last opening 11E, as indicated by arrow B5.

[0097] In the measurement process based on the second movement mode described above, similar to the example in Figure 6, multiple strain measurements can be performed on the glass substrate G within the range of a single opening 11.

[0098] Figure 8 shows another example of the measurement process. In this example of the measurement process, the glass substrate G is measured by repeatedly moving the laser beam within the range of a plurality of apertures 11 arranged in a row. This example describes measurement based on the first movement mode, but measurement based on the second movement mode can also be performed.

[0099] Specifically, in this measurement process, the laser beam repeats linear movement three times for multiple openings 11 arranged in the third row M3, by repeating the movement of the measuring device 4 in the first movement mode three times, as indicated by arrows C1 to C3.

[0100] During the first movement, the control device 5 stops the mounting platform 3, emits laser light from the laser beam irradiation unit 13, and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 along the measurement direction X1. As a result, the laser light moves relative to the glass substrate G and linearly, as indicated by arrow C1. This allows for the measurement of strain on the glass substrate G through multiple openings 11 belonging to the third row M3.

[0101] Once the first movement is complete, the control device 5 moves the mounting platform 3 along the direction Y2, which is perpendicular to the measurement direction X1, in order to change the irradiation position of the laser beam onto the glass substrate G. In this case, the laser beam changes its position in the Y-axis direction within the range of the aperture 11 belonging to the same third row M3 that it passed through during the first movement.

[0102] During the second movement, the control device 5 stops the mounting platform 3 and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 linearly along the measurement direction X2. As a result, the laser beam moves relative to the glass substrate G and linearly, passing through multiple openings 11 belonging to the third row M3, as indicated by arrow C2.

[0103] Once the second movement is complete, the control device 5 moves the mounting platform 3 along the direction Y2, which is perpendicular to the measurement direction X2. In this case, the laser beam changes its position along the Y-axis within the range of the aperture 11 belonging to the same third row M3 that it passed through during the second movement.

[0104] During the third movement, the control device 5 stops the mounting platform 3 and moves the laser beam irradiation unit 13 and the laser beam receiving unit 14 along the measurement direction X1. As a result, the laser beam moves relative to the glass substrate G and linearly, passing through multiple openings 11 belonging to the third row M3, as indicated by arrow C3.

[0105] As described above, by moving the laser beam back and forth multiple times within the range of multiple apertures 11 located in the same row, a larger number of measurement data can be acquired. When performing such measurements, it is preferable to configure the apertures 11 in a rectangular shape rather than a circular shape. By configuring the apertures 11 in a rectangular shape, the aperture area is larger compared to when they are configured in a circular shape (shown by the dashed line in Figure 8), and the measurement range for the glass substrate G can be made as wide as possible.

[0106] Figure 9 shows another example of the mounting table 3 (stage section 8) in the measuring machine 1. In this example, the opening 11 of the stage section 8 is rectangular in shape. The long side 11a of this opening 11 is formed to align with the measurement directions Y1 and Y2 in the Y-axis direction. In other words, the length dimension of the second frame section 12b of the stage section 8 in the Y-axis direction is greater than the length dimension of the first frame section 12a in the X-axis direction.

[0107] With the above configuration, when moving the laser beam along the measurement directions Y1 and Y2, a larger measurement area can be set for the glass substrate G within the range of each aperture 11. This makes it possible to acquire more measurement data.

[0108] In this example, and in any case where the laser beam is moved along the measurement directions X1 and X2 with respect to the X-axis, the longer side of the aperture 11 may be formed to align with those measurement directions X1 and X2.

[0109] Furthermore, the present invention is not limited to the configuration of the above embodiments, nor is it limited to the effects described above. The present invention can be modified in various ways without departing from the spirit of the invention.

[0110] In the above embodiment, the laser beam irradiation unit 13 was provided at the lower part of the stand 2 and the laser beam receiving unit 14 was provided at the upper part of the stand 2, but the present invention is not limited to this configuration. The laser beam irradiation unit 13 may be provided at the upper part of the stand 2 and the laser beam receiving unit 14 at the lower part of the stand 2.

[0111] In this embodiment, the glass substrate G was irradiated with laser light even while the calculation process was being executed, but the present invention is not limited to this configuration. The irradiation of the glass substrate G with laser light may be stopped while the calculation process is being executed.

[0112] In the above embodiment, a measuring device 4 having one laser beam irradiation unit 13 and a laser beam receiving unit 14 was illustrated, but the present invention is not limited to this configuration. The measuring device 4 may have multiple laser beam irradiation units 13 and laser beam receiving units 14. In this case, the multiple laser beam irradiation units 13 and laser beam receiving units 14 may be arranged at intervals in directions Y1 and Y2 that are perpendicular to the measurement directions X1 and X2 with respect to the X axis. With this configuration, the measuring device 4 can shorten its measurement time as much as possible compared to the case where it has one laser beam irradiation unit 13 and a laser beam receiving unit 14.

[0113] In the above embodiment, a birefringence measuring device was exemplified as the measuring device 4 of the measuring machine 1, but the present invention is not limited to this configuration. Laser transmission type measuring devices other than birefringence measuring devices may also be applied to the present invention. [Explanation of Symbols]

[0114] 1 Measuring instrument 3. Mounting platform 4. Measuring device 11 Opening 11a Long side of the opening 12a First frame section 12b Second Frame Section 13 Laser beam irradiation area 14 Laser light receiving section G Glass substrate (transparent) X1 Measuring direction X2 Measuring direction Y1 Measuring direction Y2 measurement direction

Claims

1. A method for measuring the properties of a transparent material, including a glass plate, using a laser transmission type measuring device, A preparation step of placing the transparent body on a mounting platform having an opening, The measurement step includes measuring the properties of the transparent body by irradiating the transparent body with laser light from the measuring device through the opening while moving the measuring device relative to the mounting table along a predetermined measurement direction without stopping the device, The aforementioned characteristic is the distortion of the transparent body, The opening of the mounting platform includes a plurality of openings arranged in a straight line, The measurement step comprises a data detection step for acquiring detection data relating to the laser light that has passed through the transparent body, and a calculation processing step for calculating the strain using a control device based on the detection data detected in the data detection step. The measuring device comprises a laser light irradiation unit that emits the laser light and a laser light receiving unit that receives the laser light. The mounting platform includes a frame portion that separates the plurality of openings, In the measurement step, the measuring device performs multiple measurements of the characteristics of the transparent body while moving linearly relative to the base described above along the direction in which the plurality of openings are arranged. The width dimension of the frame portion located between two adjacent openings is set to be smaller than the distance the laser beam travels during the execution of the calculation processing step related to a single measurement of the characteristics, as the measuring device moves. In the measurement step, during the execution of the calculation processing step, the laser light emitted from the laser light irradiation unit passes through the frame. The measurement method for a transparent body is characterized in that, in the measurement step, multiple strain measurements are performed while the laser light passes through a single aperture.

2. The measuring device is a birefringence measuring device, The method for measuring a transparent body according to claim 1, wherein the preparation step involves placing the transparent body horizontally.

3. The method for measuring a transparent body according to claim 2, wherein the transparent body is a glass substrate for a display.

4. The birefringence measuring device includes a plurality of birefringence measuring devices, The method for measuring a transparent body according to claim 2 or 3, wherein the plurality of birefringence measuring devices are arranged at intervals in a direction perpendicular to the measurement direction.

5. The method for measuring a transparent body according to any one of claims 1 to 3, wherein the opening of the mounting table is configured in a rectangular shape.

6. The opening of the mounting platform is configured in a rectangular shape. The method for measuring a transparent body according to any one of claims 1 to 3, wherein the long side of the opening is formed to be aligned with the measurement direction.

7. The method for measuring a transparent body according to any one of claims 1 to 3, wherein the relative movement of the measuring device with respect to the aforementioned stand is the movement of the measuring device.

8. The method for measuring a transparent body according to any one of claims 1 to 3, wherein the relative movement of the measuring device with respect to the aforementioned base is the movement of the aforementioned base.

9. A method for manufacturing a glass plate, comprising: a molding step of forming a glass ribbon from molten glass; a slow cooling step of slowly cooling the glass ribbon; a cutting step of cutting the glass ribbon that has undergone the slow cooling step into a glass plate of a predetermined size; and an inspection step of performing the transparent body measurement method described in any one of claims 1 to 3 on the glass plate.

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