JP2007205724A - Shape measuring device and measuring method of glass substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measuring device and a measuring method for measuring longitudinal/lateral sizes, squareness of four corners or the like of a square glass substrate used for a display substrate such as a large-size liquid crystal substrate or a plasma display substrate. <P>SOLUTION: The device comprises: an imaging means comprising a light source for irradiating the glass substrate surface and a camera for imaging a domain irradiated by the light source, on a glass inspection stand supporting the glass substrate in the tilted attitude; a head moving means for moving a head having the imaging means in both directions of the XY axes; a head position detection means for detecting the XY coordinate of the head; an image processing device for processing the image of a glass substrate peripheral edge part imaged by the camera; and an operation processing device for operating and measuring the size and the squareness of the four corners of the glass substrate, or a pore position and/or a pore diameter in addition to the size and the squareness of the four corners of the glass substrate, from position information of the XY axes by the head position detection means and peripheral edge position coordinate information of a plurality of spots on the glass substrate calculated by the image processing device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for measuring the shape of a rectangular glass substrate used for a display substrate such as a liquid crystal substrate or a plasma display substrate, such as vertical and horizontal dimensions, squareness of four corners, the position of a perforated portion, and the diameter of the perforated portion About.

  Glass plates that are rectangular and cut to the desired size are used in various applications such as architecture, mirrors, furniture, and automobiles. Depending on the purpose of use, the vertical and horizontal dimensions of the glass plate after cutting and the four corners With respect to the shape such as the angle, the position of the perforated part, and the hole diameter of the perforated part, a highly accurate dimension, squareness, and hole position accuracy may be required.

  In particular, such a requirement is remarkable in display substrates such as glass substrates for liquid crystal displays, glass substrates for plasma displays, field emission display substrates, and flat display panels such as organic EL.

  Moreover, in recent years, it has been possible to measure the size and hole position of the base plate of a display substrate such as a flat display panel, which tends to increase the size of a large number of finished products with a single large glass substrate. When the measurement is performed with high accuracy, manual measurement using a vernier caliper, a right angle ruler, or the like, which has been conventionally performed, has a problem that workability is poor and a measurement error increases. For this reason, various automatic measuring devices and auxiliary measuring devices have come to be considered.

  As a method and apparatus for measuring the vertical and horizontal dimensions and the squareness of the four corners of such a rectangular glass plate, for example, Japanese Patent Application Laid-Open No. 2003-75121 is provided on a base and linearly reciprocates horizontally. A movable table, a rotary table provided on the movable table so as to be reversibly rotatable about a vertical axis, and provided on the base at one end of the moving path of the movable table, and a rotary table for horizontally placing a rectangular glass plate Positioning means for positioning the center of the rectangular glass plate placed on the rotary table to the rotation center of the rotary table, and provided on the base so as to be opposed to both sides of the moving path of the moving table. Controls the operation of two laser rangefinders that measure the distance between the side of the placed square glass plate, the moving table, the rotary table, the positioning means, and both laser rangefinders. In addition, there is disclosed a shape measuring apparatus for a rectangular glass sheet, comprising control / calculating means for calculating the vertical and horizontal dimensions and squareness of four corners of the rectangular glass sheet from the data of both laser distance meters. (Patent Document 1).

Alternatively, Japanese Patent Application Laid-Open No. 2004-257754 discloses a number of light receiving elements that irradiate a light beam from one side of an article to be measured by a light projecting unit and that are arranged on the other side of the article and detect transmitted light from the light projecting unit. In the apparatus for optically scanning the article and measuring the size of the article, a driving means for reciprocating the light receiving element relative to the article in a direction orthogonal to the arrangement direction of the light receiving elements, and the forward movement And a moving means for moving the plurality of light receiving elements relative to the article relative to each other in the arrangement direction to move the positions of the light receiving elements different from each other. (Patent Document 2).
JP 2003-75121 A JP 2004-257754 A

  The invention described in Patent Document 1 is an apparatus for measuring the size and angle of a rectangular glass plate for a relatively small size photomask, and is fixed to the outer sides of two opposing sides of the rectangular glass plate. In order to measure the dimensions of the two opposite sides by moving the glass plate through the pair of laser distance meters, and to measure the dimensions of the remaining two sides, the means that the rotary table must be rotated 90 degrees accurately, When it is applied to the measurement of the size of the glass substrate for flat panel displays, which have been increasing in size in recent years, the size of the equipment has increased, and considering the interference with the surrounding area when rotating the glass plate, the space It is not reasonable.

  In the invention described in Patent Document 2, the article W is placed on a transparent glass plate, and the light projecting elements are arranged in a row in the Y-axis direction below the glass plate. A light receiving element arranged in a line at a position in the Y-axis direction opposite to the optical element is provided, and the length of the portion blocked by the article is measured by moving the light projecting element and the light receiving element in the X-axis direction. However, the resolution depends on the arrangement interval of the light receiving elements in the order of mm, and it is difficult to apply when a dimensional accuracy of μm is required.

  Further, if the article is a transparent glass plate, the light from the light projecting element is not allowed to pass therethrough and cannot be measured by this method. Furthermore, when trying to apply to a large-sized flat panel display glass plate with a side exceeding 2 m, there is a problem that an increase in size of the equipment is inevitable.

  The present invention has the above-mentioned problems, that is, the dimensions of the glass substrate for display such as a glass substrate for liquid crystal display, a glass substrate for plasma display, a field emission display substrate, and a flat display panel such as organic EL, and the perpendicularity or dimensions of the four corners. In addition to the squareness of the four corners, the purpose is to provide a measurement method and a measurement device that can measure the hole position and / or hole diameter in a non-contact manner in a short time with high precision and efficiency. This is intended for glass substrates.

  That is, the present invention is an apparatus for measuring the size and shape of a square glass substrate, and is irradiated by the light source and the light source that irradiates the glass substrate surface on a glass inspection table that supports the glass substrate in an inclined posture. Imaging means comprising a camera for imaging an area, head moving means for allowing the head having the imaging means to move in both directions on the XY axes, head position detecting means for detecting the XY coordinates of the head, and imaging by the camera An image processing apparatus that processes an image of the peripheral edge portion of the glass substrate, position information on the XY axes by the head position detection means, and peripheral edge position coordinate information of a plurality of locations on the glass substrate calculated by the image processing apparatus. Processing unit for calculating and measuring the hole position and / or the hole diameter in addition to the dimensions and the squareness of the four corners, or the dimensions and the squareness of the four corners of the glass substrate Consisting of a shape measuring apparatus for a glass substrate according to claim.

  Alternatively, according to the present invention, as the head position detecting means, an X-axis position reading device that extends in the X-axis direction of the head moving means and can detect the X coordinate, and extends in the Y-axis direction of the head moving means. The apparatus for measuring a shape of a glass substrate as described above, comprising a Y-axis position reader capable of detecting a Y coordinate.

  Alternatively, the present invention provides a method for measuring the dimensional shape of a rectangular glass substrate using the above-described glass substrate shape measuring apparatus, and at least each of the four sides of the glass substrate in which measurement positions are stored in advance by teaching. The head is sequentially moved to two points, the position coordinates of the head are measured by the head position detecting means, and each side of the four sides is determined by the coordinates of the edge position calculated by the image processing device from the image data captured by the camera at the head position. Is a shape measurement method for a glass substrate, characterized in that an external dimension is specified by approximating a straight line and an angle formed by two adjacent sides is calculated.

  Alternatively, according to the present invention, in the method for measuring a dimensional shape of a rectangular glass substrate using the above-described glass substrate shape measuring apparatus, a position where a desired edge position and a perforated portion of the glass substrate can be imaged with a camera in advance. Based on the teaching information, the head is moved to the edge position and the perforated portion, and the head position coordinates at the position and the image captured by the camera are used to obtain the head position. The glass substrate shape measuring method is characterized in that the position and / or hole diameter of the perforated part is calculated from the coordinate information of the glass end face edge and the perforated part edge.

  Alternatively, the present invention is characterized in that the ambient temperature of the measurement environment is measured by a sensor, and temperature correction is performed to convert it to a desired temperature in consideration of the difference in thermal expansion coefficient between the head position detecting means and the glass substrate. It is the above-mentioned glass substrate shape measuring method.

  Regardless of the size of the glass, the size of the glass substrate for display such as a rectangular flat display panel, the squareness of the four corners, the hole position, and the hole diameter can be scratched smoothly and non-contact in a short time. Highly accurate, efficient and automatic measurement.

  As shown in FIG. 1 and FIG. 2, the size and shape measuring apparatus 1 for the glass substrate 2 of the present invention is configured such that a glass substrate carried in an inclined posture by a glass transport means 30 is supported on a glass inspection table, An imaging means 10 comprising a light source 12 for irradiating illumination light to a desired edge or perforated part 2a of the glass substrate 2 and a camera 11 for imaging an area irradiated by the light source 12, and a head 63 having the imaging means 10 A head moving means 50 that can move in both directions of the XY axes, a head position detecting means 40 that can detect the XY coordinates of the head 63, and an image processing device 21 that processes the image of the peripheral edge portion of the glass substrate imaged by the camera 11. And the position information of the XY axes by the head position detecting means 40 and the peripheral edge position coordinate information of a plurality of locations of the glass substrate 2 calculated by the image processing device 21. Ri, consisting processing unit 22 for calculating measured squareness or in addition to the perpendicularity of the dimensions and corner hole positions and / or pore size, the size of the glass substrate 2 and the four corners.

  As shown in FIGS. 4 and 5, the imaging means 10 includes a plurality of LED elements (so that illumination light is irradiated to either a desired edge portion of the rectangular glass substrate 2 or the vicinity of the perforated portion 2 a. (Light emitting diode element) 12a, 12a,... Are arranged in a ring shape, and a camera 11 comprising a CCD image pickup device for picking up the area irradiated by the light source 12 is connected to a head (Y-axis guide) 63. It arranges and fixes to a side part via an attachment member.

  The positional relationship between the camera 11 and the light source 12 is such that the optical axis of the camera 11 is relative to the upper surface of the edge to be imaged on the glass substrate 2 or the normal direction of the center position of the perforated portion 2a, that is, the upper surface of the glass substrate 2. The ring illumination 12 having a plurality of LED elements 12a, 12a,... Concentrically arranged so as to be perpendicular to the upper surface side is disposed between the camera 11 and the glass substrate 2, and the optical axis of the camera 11 is And the center axis of the ring illumination 12 are made to substantially coincide with each other, and the camera 11 is arranged so that the edge of the glass substrate 2 or the perforated portion can be imaged through the center axis of the ring illumination 12.

  When a small telecentric lens is used as the lens of the camera 11, a slight positional deviation occurs between the optical axis position of the camera 11 and the measurement target position, so that the edge end face and the end face of the perforated part are slightly In addition, accurate imaging from directly above is possible without being affected by misinterpretation caused by imaging from an oblique direction.

  In other words, the telecentric lens captures images in the field of view of the camera in parallel, and captures the rounded edge end surface of the glass substrate from directly above, and the end surface (surface perpendicular to the glass surface) from an oblique direction. It does not pick up an image or captures a part of the circular end face when taking an image of the perforated part 2a from an oblique direction, and this may affect misreading by taking an image of the edge end face or the end face of the perforated part from a slight angle. In other words, precise imaging from directly above is possible.

  That is, the telecentric lens captures images in the field of view of the camera 11 in parallel, and captures the rounded edge end surface of the glass substrate from directly above, and obliquely faces the end surface (a surface perpendicular to the glass surface). Or a part of the circular end face is not captured when the perforated portion 2a is imaged obliquely.

  As shown in FIGS. 1 and 2, the glass conveying means 30 has a lower edge portion of the glass substrate 2 in a V-groove portion of a plurality of conveying receiving rolls 31, 31,. While supporting, the glass substrate 2 is carried into the glass inspection table 3 by supporting the glass substrate 2 in an inclined posture so as to lean over a plurality of free back rolls 32, 32,. Alternatively, the glass substrate 2 is unloaded from the glass inspection table 3, and the plurality of transport receiving rolls 31, 31,... Are driven by a transport motor (not shown).

  The head moving means 50 has X-axis rails 52, 52 fixed to X-axis frames 51, 51 provided in the horizontal direction near the lower side and the upper side of the glass inspection table 3 in FIGS. X-axis guides 53 and 53 that are fitted to the X-axis rails 52 and 52 and are slidable in the X-axis direction are provided along the X-axis rails 52 and 52.

  As shown in FIG. 2, one of the X-axis guides 53 and 53 may be moved on the rail by a rack and pinion gear 55 or the like by driving an X-axis drive motor 54. The X-axis guide motors 54 may be driven by a transmission mechanism such as a ball screw or a timing belt.

  The two X-axis guides 53 and 53 are connected and fixed by a Y-axis frame 61 and a connecting shaft 65 arranged in the vertical direction. A Y-axis rail 62 is fixed to the Y-axis frame 61 over the entire length of the Y-axis frame 61, and also serves as a Y-axis guide that fits the Y-axis rail 62 and is slidable in the Y-axis direction. A head 63 was provided.

  The image pickup means 10 comprising the light source 12 and the camera 11 is attached to the head 63, and the head 63 is moved to the head 63 at at least two positions of the edge portions of each side of the rectangular glass substrate and at the respective positions of the perforated portions. 50 is sequentially moved.

  The head position detecting means 40 includes an X-axis position reading device 41 extending in the X-axis direction at the side portion of the X-axis frame 51 of the head moving means 50 and a side portion of the Y-axis frame 61. And a Y-axis position reading device 51 extending in the Y-axis direction. The position readers 41 and 51 include magnetic or optical position readers. As the magnetic readers, for example, Magnescale (registered trademark) manufactured by Sony Precision Technology Co., Ltd. can be used. .

  The lower-side X-axis guide 53 is driven in the X-axis direction by driving the lower-side X-axis motor 54, but the upper-side X-axis guide 53 is moved when the lower-side X-axis guide 53 moves. The Y-axis frame 61 and the connection shaft 65 that are connected and fixed perpendicularly to the connection shaft 65 move following the connection.

  For this reason, it is desirable that the Y-axis frame 61 and the connecting shaft 65 move in the horizontal direction together with the upper-side X-axis guide 53 while maintaining the vertical posture, but the length is long enough to accommodate the large size of the glass substrate 2. The Y-axis frame 61 and the connecting shaft 65 may be slightly inclined and move in the horizontal direction.

  Therefore, in the measurement of the movement position of the lower X-axis guide 53, not only the X-axis position reading device 41 that can measure the movement position of the lower X-axis guide 53 but also the upper X-axis guide 53. It is preferable that the X-axis position reading device 41 capable of measuring the moving position is arranged and the angle of the Y-axis frame 61 is corrected by the upper and lower two position reading devices 41 and 41.

  The X-axis position reading device 41 can detect the X-coordinate position of the X-axis guide 53, and thereby the absolute movement amount of the X coordinate of the head 63 can be accurately measured. Further, the absolute value of the Y coordinate of the head (Y axis guide) 63 can be accurately detected by the Y axis position reading device 42.

  If a servo motor is used as the motor for driving the head moving means 50, the X and Y coordinates of the position of the head 63 can be obtained. However, in the present invention, high measurement accuracy is required. For the measurement of the stop position, position reading devices 41 and 42 such as a magnescale are used to capture the absolute amount of the magnescale.

  At the desired stop position of the head 63, if the desired edge portion or the perforated portion 2a of the glass substrate 2 is imaged in the area imaged by the camera 11, the image data captured by the camera even if there is a positional deviation. And the camera origin coordinates can be corrected.

  The edges of each side of the glass substrate 2 irradiated by the light source 12 and the perforations 2a are sequentially captured by the camera 11, and the original image is binarized at a desired setting level by the image processing device 21, and binarized. The X and Y coordinates of the edge position are obtained from the image, the distance from the origin in the field of view and the position coordinate of the head 63 are combined, the coordinates of the edge positions of the glass substrate, the squareness of the four corners, and the perforated portions The arithmetic processing unit 22 calculates the coordinates of the center position 2a.

  Next, a method for measuring the size and shape of the glass substrate 2 of the present invention will be described.

  Prior to measuring the dimensions of the glass substrate 2, the head (Y-axis guide) 63 is sequentially moved to at least two points on each side of the glass substrate as a reference and a plurality of perforation positions by teaching, and the X coordinate of each position , And stored in a controller or the like of the head moving means for moving the head 63 with respect to the Y coordinate.

  The measurement points are at least two edge portions of each of the four sides of the glass substrate 2, and the circular edge portions of the perforated portions 2a, 2a,. The head is sequentially moved so as to fit in the image, and an image is taken by the camera.

  If the two measurement positions for each side of the glass substrate 2 are separated from each other as much as possible, a straight line obtained by averaging these measurement points becomes one side of the glass substrate 2, so that the measurement accuracy is improved. This is desirable.

  Next, the unmeasured glass substrate 2 is carried into a predetermined position on the glass support 3 by the glass conveying means 30, and the head 63 is moved at least on each side of the glass substrate 2 by the head moving means 50 based on the teaching information. The edge part is irradiated with illumination light from the light source 12 such as ring illumination in a state where the measurement point is sequentially moved to the vicinity of the center position of each of the two measurement points and the perforated part 2a, and the head 63 is moved to each measurement position and stopped. Then, the camera 11 images the edge portion of the glass substrate 2.

  At the same time, the X-coordinate and Y-coordinate of the head 63 sequentially moved to the measurement point and the center of the punching portion 2a are measured by the X-axis position reading device 41 and the Y-axis position reading device 42 of the head position detecting means 40.

  The original image captured by the camera 11 is once binarized by the image processing device 21 and read from the position deviation device between the edge position and the origin position within the range of the image and the position reading device such as the magnescale. Position information combined with the position coordinates of the head 63 is stored in an arithmetic storage device, and linear approximation is performed using at least two position coordinates measured per side of the glass substrate 2.

  For each side of the glass substrate 2, the measurement points of each side are connected and approximated by a straight line, and the length of each side is calculated from the coordinate information from the intersection point of the quadrangle formed by each straight line. Further, as shown in FIG. 8, an angle θ formed by two adjacent sides can also be calculated.

  For the measurement of the position and / or the hole diameter of the circular perforated part 2a, the entire circular shape of the perforated part 2a is previously accommodated in the visual field of the camera 11 by teaching, and at the time of measurement, as shown in FIG. The center position coordinate Q1 of the punching portion 2a can be obtained by the image processing apparatus, the center position coordinate Q1 of the image of the punching portion 2a imaged by the camera, the coordinates read from the magnescale of the position of the head 63, and the quadrangle The distance from the coordinates of each side can be calculated by an arithmetic unit.

Further, in order to make the dimensional accuracy of the glass substrate 2 which is the measurement object of the present invention more severe, the ambient temperature of the measurement environment is measured by the temperature sensor 5 as shown in FIG. The thermal expansion coefficient ((11 ± 1) × 10 ⁻⁶ / ° C.) when a magnescale is used as the position reading device 41 of the 63 position detection means 40 and the thermal expansion coefficient (8.5 × 10 ⁶ ) of the glass substrate 2. ^In consideration of the difference (2.5 × 10 ⁻⁶ / ° C.) from ⁻⁶ / ° C., temperature correction is performed to convert the temperature to a desired temperature, for example, normal temperature of 20 ° C. that can guarantee the accuracy of the magnescale. Incidentally, if the temperature changes by 5 ° C. with a length of 2000 mm, a correction amount of 25 μm is required.

  The ring illumination as the light source 12 may be a Circline (registered trademark) high-frequency fluorescent lamp or the like, but considering the lifetime, damage due to impact, etc., a large number of LED elements 12a, 12a,. The LED elements 12a, 12a,... Are arranged in such a manner that the illumination directions of the LED elements 12a, 12a,. The shape by each optical axis is preferably a conical shape.

  The camera 11 is preferably a two-dimensional area camera. When a line camera is used, the scanned image data must be stored in the arithmetic processing unit 22, and assembled into a two-dimensional area for processing. Therefore, the image processing unit 21 calculates the center of the perforated part 2a. Is inefficient when using.

  The target glass substrate 2 is a general glass substrate whose edge is chamfered or polished, and in particular, a glass substrate for a liquid crystal display or a plasma display having a rounded cross section. It is effective for various rectangular display substrates such as glass substrates, field emission display substrates, and flat display panels such as organic EL.

  The glass substrate 2 to be inspected is, for example, a rectangular plate having a thickness of 0.5 mm to 3 mm, a small size glass substrate having a vertical side of 800 mm × a horizontal side of about 900 mm, and a large size of about 2200 mm × a horizontal side of about 2400 mm. The glass substrate 2 and the end surface 2a of the glass substrate 2 are processed to have a round cross-section arc shape and have a perforated portion.

  When measuring each side of the glass substrate 2 at a large number of measurement points, first, a straight line approximation is performed by the least square method, and the linearity of each side of the glass substrate due to variations in measurement points greatly deviating from this straight line. It is also possible to determine pass / fail.

  The operation of the present invention will be described below.

  In measuring the dimensions of the vertical and horizontal sides of the glass substrate 2, the head 63 is moved to a desired position only by the controller 4 of the head moving means 50 that drives the head 63 in the X-axis and Y-axis directions. The head 63 can be moved almost to a predetermined position by the controller 4, but strictly speaking, the position where the head finally stopped is not the length measured as an absolute amount, but a position designated by calculation based on the count amount of the pulse signal. Since the position is supposed to stop, there is a possibility that an error may occur in the stop position.

  That is, the stop position accuracy of the head 63 by the controller 4 of the head moving means 50 is not an absolute amount, and may be less than ± 0.1 mm, which is a target value of the required dimensional accuracy of the glass substrate.

  For this reason, in the present invention, the controller 4 of the head moving means 50 does not move the head 63 to the position stored at the time of teaching and take out the coordinate position obtained from the controller 4, but extracts a magnetic scale or the like provided separately. Since the position coordinates of the head 63 are measured as absolute amounts using the position reading devices 41 and 42 capable of measuring the absolute amount of the position, even if there is an error in the stop position of the head position, the true stop position is accurately and accurately measured. it can.

  Furthermore, since the camera 11 attached and fixed to the head 63 images the edge position of the glass substrate 2 and calculates the position from the camera origin, it is possible to measure the dimensions with high accuracy in units of μm.

  The reason why the optical axis of the camera 11 is set to the normal direction of the glass substrate surface from the edge portion of the glass substrate 2 is to detect the position of the outermost peripheral edge portion of the end portion of the glass substrate 2.

  Further, since the optical axis of the camera 11 and the optical axis of the ring illumination as the light source 12 are matched, the camera 11 images the edge portion of the glass substrate 2 so as to pass through the opening of the ring illumination 12. Yes, the ring illumination 12 does not get in the way. Further, the LED elements 12a, 12a,... Of the ring illumination 12 are irradiated only in the edge side direction of the glass substrate 2, and the light shielding cover 12b is provided on the camera 11 side. It does not enter the camera 11.

  In addition, since the center of the optical axis of the ring illumination 12 in which a plurality of LED elements 12a, 12a,... Are arranged concentrically at the end position of the glass substrate 2 or the center position of the perforated part 2a is provided. The illumination light is evenly applied to the respective portions of the end surface under relatively the same conditions without causing shadows on the end portions or the edge portions of the perforated portion 2a.

  Furthermore, since a small telecentric lens is used as the lens of the camera 11, a slight positional deviation occurs between the optical axis position of the camera 11 and the measurement target position. However, it is not affected by misinterpretation by imaging from an oblique direction, and it is possible to perform precise imaging as if the optical axis of the camera 11 is directly above the measurement point.

  That is, the telecentric lens can image the rounded edge end surface of the glass substrate from directly above, image the end surface (surface perpendicular to the glass surface) from an oblique direction, and image the perforated portion 2a from an oblique direction. Sometimes there is no trouble caused by imaging a part of the circular end face.

  Furthermore, the two X-axis position reading devices 41 are provided above and below because the X-axis guide 53 on one side is driven by the X-axis motor and the other X-axis guide 53 follows in the X-axis direction. There are cases in which the Y-axis frame 61 and the connecting shaft 65 are long and cannot be followed in a vertical posture. This is because there are cases where the positions of the two X-axis guides are shifted.

[Example 1]
First, as shown in FIGS. 1 and 2, a rectangular glass substrate 2 in an inclined posture is carried onto a glass inspection table 3 in an inclined posture by a glass conveying means 30, and stopped at a predetermined position by a position sensor (not shown). To do. The glass substrate 2 supports the lower edge on the glass inspection table 3 with conveyance receiving rolls 31, 31,... Having a V-shaped cross section, and a free back roll 32, 32 having a plurality of rear and back surfaces arranged vertically and horizontally. · · Is supported by.

Subsequently, three points for each side of the glass substrate 2 as shown in FIG. 6, a total of 12 measurement points P _{1 to} P ₁₂ around the entire circumference of the glass substrate, and the center of the perforated part provided at the desired position Teaching is performed so as to move the head to the position, and the position coordinates are stored.

  As shown in FIGS. 4 and 5, the camera 11 as an imaging means is a CCD area camera, and the light source 12 arranged between the camera 11 and the glass substrate 2 is commercially available with the optical axes aligned as much as possible. The ring illumination 12 was used.

  That is, the light source 12 is ring illumination, and a plurality of LED elements 12a, 12a,... Are arranged in two rows concentrically at an equal pitch, the irradiation direction is only on the glass substrate 2 side, and the camera 11 side Is a commercially available product in which direct illumination of the illumination is not irradiated by the shielding cover 12b of the ring illumination, and the irradiation direction of each LED element 12a, 12a,. Each LED element 12a, 12a,... Has a conical shape due to a plurality of optical axes.

  Further, the camera 11 is set to take an image of the edge portion of the glass substrate 2 as shown in FIG. 4 through the space at the center of the ring illumination, or to take an image of the entire perforated portion 2a as shown in FIG. . The distance between the camera 11 and the ring illumination 12 is 150 mm as an example, and the distance between the ring illumination 12 and the glass substrate 2 is 30 mm, but is not limited thereto.

  The imaging means 10 is fixed to a head 63 that is movable in the X axis and Y axis by a head moving means 50, and X axis magnescales 41, 41 are respectively provided on two upper and lower X axis frames 51, 51 of the head moving means 50. The Y-axis frame 61 is provided with a Y-axis magnet scale 42. When the head 63 is stopped, the X- and Y-axis magnet scales 41, 41, 42 read the position coordinates of the head, and the arithmetic processing unit 22 passes through the controller. Remember it.

As shown in FIG. 6, the heads are sequentially arranged from the measurement point P ₁ to the measurement point P ₁₂ with respect to the edge positions of the total 12 points of P _{1 to} P _{12 on} the entire circumference, 3 points for each side of the glass substrate 2. 63 is moved to measure the position coordinates.

At the positions of the measurement points P _{1 to} P _{12 on} the outer peripheral portion of the glass substrate 2, as shown in FIG. 7, the edge position of the glass substrate 2 is imaged with the camera 11, and the image processing apparatus (see FIG. 3) The coordinates of the edge position P point are obtained, the position information is sent to the arithmetic unit, and in the arithmetic unit, each of P _{1 to} P ₁₂ is determined by the difference between the coordinate at the time of measurement and the coordinate at the time of teaching, and the position information of the head. The exact edge position of a point can be calculated.

  As shown in FIG. 6, as a result of measuring the edge positions of three locations per side, each side is linearly approximated by the least square method from the coordinates, and further, the distance between two opposing sides is sequentially obtained, The lengths of the four sides are obtained. If the length of each side is within ± 0.4 mm of the reference value, it is OK, and if it exceeds 0.4 mm, it is NG.

The squareness of the four corners is obtained from the side L ₃ obtained from the coordinates of the three edge positions P _{7 to} P _{9 and} the coordinates of the three edge positions P _{10 to} P ₁₂ as shown in FIG. The angle θ at which the two sides intersect is obtained from the side L _4, and if the angle θ is within 90 ± 0.01 degrees, it is determined as OK.

Further, with respect to the center coordinates Q _{1 to} Q ₄ and the hole diameter of the perforations 2a, 2a,... Shown in FIG. 6, the CCD camera 11 and the light source 12 as shown in FIG. An image obtained by capturing the edge of the perforated portion 2a in the direction is as shown in FIG. Calculating the center coordinates Q ₁ and hole diameter of the perforated portion by the image processing apparatus, said center coordinates Q ₁ is calculated and one side of the X-axis direction of the glass substrate, the processing unit a distance to one side of the Y-axis direction, perforations If the site is within ± 0.4 mm compared to the reference position, it is OK, and if it exceeds this range, it is NG.

  In this way, the dimension and shape measuring method and apparatus of the present invention measure the dimensions of the four sides of the glass substrate 2, the squareness of the four corners, the position of the perforated part 2a, and the hole diameter, and these data are stored in the host computer 23. If it is transmitted, output of inspection report, inspection daily report, etc. is automatically output, and data management is easy.

  Even if the present invention is a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a field emission display substrate, a flat display panel such as an organic EL, etc. A measuring method and a measuring apparatus capable of efficiently measuring a hole position and / or a hole diameter in addition to a dimension and a squareness of four corners in addition to a dimension and a squareness of a corner in a short time, with high accuracy in μm units. It is for the purpose of provision.

The whole front view of the shape measuring apparatus of this invention. The whole side view of the shape measuring apparatus of this invention. The whole conceptual diagram of the shape measuring apparatus of this invention. The figure which shows the positional relationship of the camera of a shape measuring apparatus of this invention, a light source, and a glass substrate edge. The figure which shows the positional relationship of the perforation part of the camera of the shape measuring apparatus of this invention, a light source, and a glass substrate. The figure which shows an example of the measurement position of the glass substrate measured by the shape measuring method of this invention. Explanatory drawing of the measuring method of the edge part of a glass substrate. Explanatory drawing of the measuring method of the squareness of the four corners of a glass substrate. Explanatory drawing of the measuring method of the perforation part center of a glass substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shape measuring apparatus 2 Glass substrate 2a Perforation part 3 Glass inspection stand 4 Controller 5 Temperature sensor 6 Temperature logger 10 Imaging means 11 Camera 12 Light source 21 Image processing apparatus 22 Arithmetic processing apparatus 23 Host computer 30 Glass conveyance means 31 Conveyance receiving roll 32 Free Back roll 40 Head position detecting means 41 X-axis position reading device 42 Y-axis position reading device 50 Head moving means 51 X-axis frame 52 X-axis rail 53 X-axis guide 54 X-axis motor 55 Rack & pinion 61 Y-axis frame 62 Y-axis rail 63 head (Y-axis guide)
64 Y-axis motor 65 Connecting shaft

Claims (5)

In an apparatus for measuring the size and shape of a square glass substrate, on a glass inspection table that supports the glass substrate in an inclined posture, a light source that irradiates the glass substrate surface, and a camera that images an area irradiated by the light source; An image pickup means, a head moving means for moving the head having the image pickup means in both directions of the XY axes, a head position detecting means capable of detecting the XY coordinates of the head, and a peripheral edge portion of the glass substrate imaged by the camera Based on the position information of the X and Y axes by the head position detection means and the peripheral edge position coordinate information of a plurality of positions of the glass substrate calculated by the image processing apparatus, the dimensions of the glass substrate and the four corners And an arithmetic processing unit for calculating and measuring the hole position and / or hole diameter in addition to the angle or the size of the glass substrate and the squareness of the four corners. Shape measuring apparatus for a glass substrate to be. As the head position detecting means, an X-axis position reading device extending in the X-axis direction of the head moving means and detecting the X-coordinate, and an Y-axis direction extending from the head moving means to detect the Y-coordinate 2. The glass substrate shape measuring device according to claim 1, comprising a free Y-axis position reading device. 3. A method of measuring a dimensional shape of a rectangular glass substrate using the glass substrate shape measuring apparatus according to claim 1 or 2, wherein at least two points on each of the four sides of the glass substrate in which measurement positions are stored in advance by teaching. The head is sequentially moved, the position coordinates of the head are measured by the head position detecting means, and each edge of the four sides is linearly defined by the coordinates of the edge position calculated by the image processing device based on the image data captured by the camera at the head position. A shape measurement method for a glass substrate, characterized in that an external dimension is specified by approximation and an angle formed by two adjacent sides is calculated. In the method for measuring a dimensional shape of a square glass substrate using the glass substrate shape measuring apparatus according to claim 1 or 2, a desired edge position and a perforated portion of the glass substrate are previously located at a position where an image can be captured by a camera. The head position is taught as described above, and based on the teaching information, the head is moved to the edge position and the punched portion, and the position coordinates of the head at the position and the glass obtained from the image captured by the camera are obtained. A method for measuring a shape of a glass substrate, wherein a position of a perforated portion and / or a hole diameter is calculated from coordinate information of an end face edge and a perforated portion edge. 5. The temperature correction for converting to a desired temperature is performed by measuring the atmospheric temperature of the measurement environment with a sensor and taking into account the difference in thermal expansion coefficient between the head position detecting means and the glass substrate. Of measuring the shape of a glass substrate.

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