JP3859859B2 - Defect detection method and apparatus for transparent plate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for detecting fine bubbles, internal defects such as foreign matters, and surface defects such as scratches in a transparent plate-like body such as a glass plate.
[0002]
[Prior art]
As a conventional technique in a transparent plate-like defect detection method and apparatus such as a glass plate or a resin plate, there are inspections for defects in transparent plate-like bodies connected in a ribbon shape, and transparent plate-like bodies after cutting. Various things are known for each, such as those for inspecting defects.
[0003]
First, for detecting defects in a ribbon-like transparent plate-like body, as shown in Japanese Patent Laid-Open No. 1-189549, a mechanism for transporting glass and light from a linearly arranged light source are passed through a slit. In addition, a glass defect detection device is disclosed in which, by projecting onto glass, internal defects and surface defects of glass are captured by a one-dimensional camera as light shadows, and the quality of the glass is determined after conversion into two-dimensional data.
[0004]
Further, as shown in Japanese Utility Model Laid-Open No. 3-27343, it is provided separately from one surface of a moving plate glass and provided separately from a point light source for irradiating the plate glass with light and another surface of the plate glass. A screen for projecting an image formed by transmitted light that is irradiated from the light source and transmitted through the plate glass, and a plate glass defect detection device that scans the screen and detects an image of the defect of the plate glass by a line sensor are disclosed.
[0005]
Furthermore, using the difference in refraction of light as seen in JP-A-61-176838 and JP-A-61-176839, the distortion of the background line is captured, the transmitted light of the laser beam by the laser flying spot, The thing using reflected light is mention | raise | lifted.
[0006]
In addition, as for detecting a defect of a transparent plate-like body after cutting, for example, in Japanese Patent Laid-Open No. 4-320951, a glass plate to be inspected with a smooth surface is supported on a support base, and the side surface of the glass plate On the other hand, a white light beam of an appropriate angle is projected and totally reflected by the inner surface, and the scattered light of the totally reflected light due to defects existing on the surface is visually observed on the front side or the back side, or received. A glass plate surface defect inspection method for detecting the defect by receiving light by a detector, a frame fixed to a base board and supporting four sides of a square glass plate to be inspected having a smooth surface, and supported by the frame In addition, two linear light sources projecting a white light beam having an appropriate angle to the two side surfaces orthogonal to each other of the rectangular glass plate, and scattered light due to a defect of total reflection light from the inner surface of the rectangular glass plate are received. Receiving camera and reflection of the side surface Surface defect inspection apparatus further comprising a glass plate and the shielding plate to eliminate interference is disclosed for receiving image by.
[0007]
[Problems to be solved by the invention]
First, as disclosed in Japanese Patent Laid-Open No. 1-189549, light from a linearly arranged light source is projected onto a plate glass that moves through one slit, thereby detecting a defect of the plate glass as a shadow of light with a one-dimensional camera. However, in the example of image processing, it is impossible to discriminate between dust, dirt and defects adhering to the transparent plate-like body, and dust, dirt, etc. are erroneously detected when trying to detect minute defects.
[0008]
Next, as in Japanese Utility Model Publication No. 3-27343, a moving plate glass is irradiated with a light beam from a point light source, and a projected image on a screen after passing through the plate glass is scanned with a one-dimensional camera. In the detection example, distortion defects can be detected, but they are easily affected by disturbances (external light, dust, dirt, etc.), and fine defects cannot be detected.
[0009]
Furthermore, as disclosed in JP-A-61-176838-9, a plurality of line arrays that are equally spaced at intervals smaller than the size of the defect portion to be detected are observed through a transparent plate, and the defect portion is line-formed. In the example of detection processing by the camera as the disturbance of the column, the regular pulse width and pitch signals are caused by the difference in the refractive index of the light passing through the defective part by scanning across the line column at equal intervals. This method uses the detection of different signals, and in detecting various defects of transparent plates with defects that are fine or light, it is certain that the line train will not be disturbed if this method is applied. Cannot be detected. Moreover, it is impossible to distinguish between dust, dirt and defects attached to the transparent plate-like body, and dust and dirt are erroneously detected.
[0010]
For devices using laser light transmitted or reflected by a laser flying spot, the device itself is large and expensive, and it is possible to detect very fine defects, but there are also many false detections due to dust, etc. There is a problem.
[0011]
That is, in any of the conventional detection methods as described above, any of the various defects of the transparent plate-like body, for example, internal defects or scratches in the transparent plate-like body such as bubbles and foreign matters There has been a problem that detection of fine defects on the order of microns such as surface defects cannot be reliably performed.
[0012]
Furthermore, for JP-A-4-320951 shown as detecting a defect in a transparent plate after cutting, a glass plate is supported on a support base and a white light beam is projected onto the side surface of the glass plate. , Which requires a shielding plate for eliminating interference with the image-receiving camera due to the reflected light from the side surface, and in this publication, when the glass plate is large, the glass plate is curved, but there is no problem for defect inspection. Although there is a statement that, in recent years, the substrate has also become larger and thinner, and when inspecting a large-sized thin plate, the distance between the camera and the glass plate does not become constant due to bending, the focus becomes sweet, and minute defects are detected When trying to do so, there is a possibility that accurate defect inspection cannot be performed due to a decrease in detection sensitivity. Furthermore, when the size of the glass plate is increased, the amount of light projected is gradually attenuated and weakened as the distance from the end face increases, and the brightness of the defective part located away from the light source decreases, so it is determined to be smaller than the actual size. Even if the defect has a size outside the allowable range, it may be erroneously determined that the size is within the allowable range.
[0013]
Furthermore, although there is a description that the glass plate is inspected by moving the two-dimensional camera in the X-axis and Y-axis directions, this method has a drawback that it takes time.
[0014]
[Means for Solving the Problems]
The present invention has been made in view of the above points, and has been affected by dust and dirt due to extremely fine micron-sized bubbles, internal defects such as foreign matters, and surface defects such as scratches, which have been difficult in the past. The objective is to be able to inspect all the products automatically at a low cost, reliably and quickly . That is, the present invention irradiates light from one end surface of the transparent plate that is carried and positioned on the air table, scans the surface of the transparent plate with a line camera provided above the transparent plate, In the method of detecting a defect in the transparent plate-like body using the obtained image signal, the linear light source can be moved up and down, close to the end surface of the transparent plate-like body only during the inspection, and slightly below the top of the conveyor when not inspecting is retracted to, and freely pass during unloading of the transparent plate-shaped object, is totally reflected repeatedly between the front and back surfaces of the transparent plate-shaped object transparent plate-shaped object by irradiating said linear light source from the end face only, the transparent plate-shaped object The entire surface of the transparent plate is imaged and scanned with an inclination angle of θ with respect to the normal of the transparent plate surface while moving the line camera provided obliquely above at a constant speed in a horizontal direction perpendicular to the scanning direction of the camera, Bounds the predetermined level of the obtained luminance signal A defect detection method for a transparent plate-shaped object, characterized in that to determine the acceptability and.
Alternatively, the present invention corrects the sensitivity according to the distance between the linear light source irradiated from the end face of the transparent plate-like body and the scanning position of the moving camera, and eliminates the difference due to the distance from the light source. This is a defect detection method for a transparent plate-like body as described above .
Alternatively, the present invention provides an air table for levitating the transparent plate-like body, a positioning means for carrying the levitated transparent plate-like body by the carrying means, and stopping the positioning at a predetermined position, and one end face of the transparent plate-like body. A linear light source that emits light from the end face, a line camera that is provided obliquely above the transparent plate-like body surface and scans the transparent plate-like body surface in the width direction, and the line camera at a constant speed in the direction of transporting the transparent plate-like body a traveling means for traveling, Ri Do a predetermined level processes the luminance signal taken from the determination processing unit for determining processing quality as a boundary, the belt-shaped light source formed of the linear light source from a plurality of optical fibers, the belt-like light source is close to and away from the one end surface of the positioned transparent plate-shaped object, the defect of the transparent plate-shaped object, characterized in that a lifting means through which light enters from the end surface in proximity to the end face of the transparent plate-shaped object only when testing A detection device.
Alternatively, the present invention provides a transparent plate that includes a cylindrical pressing roller that is in contact with one end surface of a transparent plate-like body that has been levitated by an air table and that rotates freely, and a cylindrical driving roller that is in contact with an opposite end surface. two opposite sides of the Jo body pressed sandwich is the defect detection apparatus of the transparent plate-shaped object described above, characterized in that a conveying means adapted to convey the transparent plate-shaped body with rotation of said drive roller .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a method and apparatus for detecting fine bubbles, internal defects such as foreign matter, and surface defects such as scratches in a transparent plate-like body such as a glass plate or a resin plate such as acrylic. It consists of a structure as described in the means for solving.
[0016]
That is, the apparatus 1 includes an air table 12 that floats the transparent plate G, a transport unit 10 that transports the floated transparent plate G, a positioning unit 20 that stops positioning at a predetermined position, and a transparent plate A linear light source 3 that is close to one end face of G and irradiates light from the end face, and is provided obliquely above the surface of the transparent plate G, and has an inclination angle θ with respect to the normal of the transparent plate G surface. A plurality of line cameras 5,... That scan the surface in the width direction, and traveling means 30 that causes the line cameras 5, 5,. Further, a lifting / lowering means 40 is provided, which comprises a personal computer 52 as a determination processing means for processing the picked-up brightness / darkness luminance signal and determining the quality with a predetermined level as a boundary, and preferably allowing the linear light source 3 to move up and down.
[0017]
The inclination angle θ between the scanning line of the line camera and the normal line of the transparent plate-like body G surface is about 0 to 60 degrees, but the detection sensitivity is preferably in the range of 30 to 45 degrees.
The air table 12 is provided on the gantry 7, and a plurality of pores are provided at equal intervals on a table plate having a flat upper surface so that high-pressure air is ejected from the pores. The transparent plate-like body G can be levitated.
[0018]
The upper part of the air table 11 is sandwiched and pressed by pressing rolls 21, 21,... That are brought into contact with the end surface of the transparent plate-like body G that is carried and floats on the air table 11, and the driving rolls 14, 14,. A conveying means 10 is provided.
[0019]
The transport means 10 has one end of a plurality of press levers 22, 22,... Mounted on a press frame 23 provided in parallel with the transport direction of the transparent plate G, and the press levers 22, 22,. Cylindrical pressing rolls 21, 21,... That are in contact with the end surface of the transparent plate-like body G and freely rotate are provided at the respective other end portions.
[0020]
.. Are provided between the pressing levers 22, 22,... And the pressing frame 23, respectively, and the end face of the transparent plate G is appropriately pressed by the elastic force of the springs 24, 24,. Adjustment is performed by the pressing position adjusting means 25 so that the pressure can be always pressed.
[0021]
Further, cylindrical drive rolls 14, 14,... Are brought into contact with the end faces of the sides opposite to the sides in contact with the pressing rolls 21, 21,. 14,... Are rotated by a drive motor 15 via a drive belt 16.
[0022]
Further, a positioning means comprising a stopper that can be moved up and down is provided at a predetermined position at the tip of the air table 12, and when the transparent plate G comes to a predetermined position on the air table 12, the tip end surface of the transparent plate G is lowered. And the stopper are brought into contact with each other to be positioned and stopped at that position.
[0023]
The linear light source 3 allows light to enter from the end surface of the transparent plate G, bundles a plurality of elongated optical fibers into a strip shape, and forms a cross-sectional shape of the portion irradiated with light at the tip of each fiber in a linear shape. This is a strip-shaped light source that guides light from a light source such as halogen light or mercury light provided near the other end of the optical fiber to the end surface of the transparent plate-like body via the optical fiber. 6. As shown in FIG. 7, the linear light source 3 is attached to the lower position of the levitation conveyor 17 provided between the carry-out conveyor 13 and the air table 12 via the light source support member 8, and can be moved up and down together with the levitation conveyor 17 by the lifting means 40. It was provided so that.
[0024]
The linear light source 3 is not limited to the bundle of the optical fibers, and the end face of the transparent plate G may be irradiated with light from the light source through a single elongated slit.
[0025]
Further, the irradiation direction angle of the light source of the linear light source 3 is arranged so as to irradiate the end face of the transparent plate G from an angle φ (about 10 degrees) obliquely below the horizontal plane, as shown in FIG. The direct light from the linear light source 3 is shielded at a position above the linear light source 3 between the linear light source 3 and the line cameras 5, 5,. A cover 9 was provided.
[0026]
The elevating means 40 is provided with an elevating member 44 and a shielding plate 43 via a mounting member 42 at the tip of the cylinder rod of the elevating cylinder 41. A rotatable push-up roll 45 that abuts the lower end of the levitation conveyor 17 is provided on the upper part of the elevating member 44, and the levitation conveyor 17 is moved up and down by the operation of the elevating cylinder 41.
[0027]
At the same time, the shielding plate 43 rises with the operation of the elevating cylinder 41 and is brought into contact with the lower end side of the tip of the transparent plate G, so that the light from the linear light source 3 is transmitted from the lower surface other than the end surface of the transparent plate G. This prevents the incident.
[0028]
The tip of the linear light source 3 is attached and fixed below the levitation side of the levitation conveyor 17 via the light source support member 8, and is brought close to the tip side end surface of the transparent plate G as the levitation conveyor 17 rises.
[0029]
Further, as shown in FIG. 1, the traveling means 30 is provided with a plurality of line cameras 5,... With a θ angle obliquely above the transparent plate G, and the surface of the transparent plate G Are scanned by the line cameras 5, 5,.
[0030]
As shown in FIG. 5, the line cameras 5, 5,... Have a support column from the gantry 7, and a traveling rail 32 is provided in a direction parallel to the transport direction of the transparent plate G on the upper end side of the support column. A traveling frame 33 is horizontally provided on a guide that fits the rail 32 and travels along the rail 32 in the width direction across the conveyor. The line cameras 5, 5,... Are attached and fixed to the traveling frame 33 in the same direction at the same angle via the attachment members 34, 34,.
[0031]
Further, as shown in FIG. 4, the pressing position adjusting means 25 adjusts according to the size of the transparent plate G to be inspected. The press rolls 21, 21,... Rotatably provided at the ends of the press levers 22, 22,... Have an appropriate pressing force on the end surface of the transparent plate-like body G by the elastic force of the springs 24, 24,. The position of the pressing frame 23 can be freely adjusted by operating the handle so that it can always be pressed.
[0032]
Further, the personal computer 52 serving as the determination processing means binarizes the brightness signal of the brightness captured by the plurality of line cameras 5, 5,. When the size of the pixel to become exceeds a predetermined number of pixels, the code quality is judged.
[0033]
Further, the sensitivity correction means 60 fixes the position of the linear light source 3 irradiated from the end face of the transparent plate G, and when the line cameras 5, 5,. Since the scanning position of 5, 5,... Is away from the linear light source 3, the illuminance decreases, so that the slice level for binarization is set for sensitivity correction according to the distance between the scanning position and the linear light source 3. The difference due to the distance from the linear light source 3 is eliminated by either reducing the brightness or increasing the brightness signal of brightness.
[0034]
The defect inspection apparatus 1 according to the present invention has the above-described configuration. Next, a method for inspecting defects using the apparatus will be described.
First, the transparent plate-like body G is conveyed by the carry-in conveyor 11, a plurality of pores are provided on the upper surface, and the transparent plate-like body G such as a glass plate or a resin plate is provided on the air table 12 that ejects high-pressure air from the pores. Bring in and lift up.
[0035]
Subsequently, the cylindrical pressing rolls 21, 21,... That freely rotate are brought into contact with one end surface of the side parallel to the direction in which the transparent plate G in the floated state is conveyed, and the opposite end surface of one side is brought into contact with the end surface. The cylindrical drive rolls 14, 14,... Are pressed and sandwiched, and conveyed to a predetermined position at the tip of the air table 12.
[0036]
When the transparent plate G moves and approaches the predetermined position at the tip of the air table 12 by the transport means 10, the drive motor 15 is decelerated by a sensor (not shown) provided in the air table 12 and is provided near the tip of the air table 12. The stopper is lowered to a height at which it comes into contact with the front end side of the transparent plate G, and the transparent plate G is stopped in a floating state.
[0037]
Subsequently, the levitation conveyor 17 between the air table 12 and the carry-out conveyor 13 is lifted and floated by the operation of the lifting cylinder 41, and the linear light source 3 provided at the lower part of the levitation conveyor 17 is slanted on the end surface on the front end side of the transparent plate G Move close to the bottom. At the same time, the shielding plate 43 raised by the elevating means is brought into contact so as to slightly protrude from the front end side of the transparent plate-like body G, and the light of the linear light source 3 from obliquely below enters from the lower surface of the transparent plate-like body G. I tried not to.
[0038]
Further, a shielding cover 9 is provided on the center line connecting the linear light source 3 and the line cameras 5, 5,... Above the tip of the linear light source 3, and the light from the linear light source 3 is directly reflected on the line camera 5, 5, so that it is not incident on.
[0039]
The linear light source 3 is incident obliquely from the end surface of the transparent plate G through a fiber bundled with light from the light source, and repeatedly and totally reflects between the front and back surfaces of the transparent plate G. When light is applied to internal defects such as bubbles or foreign substances in the plate-like body G, or light is applied to surface defects such as scratches, the light of the defective portions is scattered, and the scattered light is scattered to the line sensors 5, 5,・ ・ It is imaged in.
[0040]
As shown in FIGS. 1 and 5, the entire width of the transparent plate G is divided and scanned by a plurality of line cameras 5, 5,... Arranged in a line above the air table 12. The image data picked up by the sensors 5, 5,... Is converted into an electric signal representing the luminance level by the camera controller, and then taken into the image processing device 51, and assembled and synthesized into the inspection width of the transparent plate G.
[0041]
The obtained luminance waveform is binarized at the set slice level, divided into a low luminance signal “0” and a high luminance signal “1”. If the number of pixels of the high luminance signal is larger than the specified number, it is regarded as a defect and the personal computer The X coordinate, the Y coordinate, etc. are stored in the.
[0042]
3 and 5 scans the entire surface of the transparent plate G while each line camera 5, 5,... Runs from the front side to the rear side of the transparent plate G. Then, each luminance signal waveform for each scanning line is binarized at the slice level in the same manner as described above, and quality is determined.
[0043]
In this way, while the transparent plate G is scanned by the plurality of line cameras 5, 5,..., The traveling means 30 is moved to detect defects on the entire surface of the transparent plate G.
[0044]
Further, sensitivity correction is performed according to the distance between the linear light source 3 irradiated from the end face of the transparent plate G and the scanning position of the traveling camera.
Further, when the position of the linear light source 3 irradiated from the end face of the transparent plate G is fixed and the line cameras 5, 5,. Since the illuminance gradually decreases far from the linear light source 3 and the illuminance gradually decreases, the sensitivity correction means 60 performs sensitivity correction according to the distance between the scanning position and the linear light source 3, that is, binarization. In order to eliminate the luminance difference due to the distance from the linear light source 3 and to make it constant, correction is performed such as lowering the slice level or increasing the bright and dark luminance signal level.
[0045]
Further, for several millimeters from the edge of the transparent plate G, a masking process or the like is performed in a soft manner so that even if scattered light from the seaming part is incident on the line cameras 5, 5,. To do.
[0046]
When the inspection is completed for the entire surface of the transparent plate G, the shielding plate 43 and the elevating member 44 of the linear light source 3 are lowered by the backward movement of the elevating cylinder 41 of the elevating means 40.
As the elevating member 44 is lowered, the levitation conveyor 17 is lowered, the linear light source 3 fixed to the lower part of the levitation conveyor 17 is also lowered, and the transparent plate G can be carried out. The transparent plate was carried out.
[0047]
Further, if the obtained results are stored and processed by a personal computer or the like, the X-axis and Y-axis directions of the transparent plate G are combined with the travel position by the travel means 30 of the line cameras 5, 5,. Management information can be obtained based on the position and size of the defect.
[0048]
As in the present invention, the defect is inspected in the state where the transparent plate G is levitated on the air table 12, so that the transparent plate G is compared with the case where it is placed on the table and inspected. Defect inspection can be performed under favorable flat conditions without bending.
[0049]
Since a very small defect must be detected, focus is required when imaging the surface of the transparent plate, and the air table 12 is a size of the transparent plate G that floats on the air table 12. Even if the plate thickness changes, the air volume can be adjusted so that the flying height of the transparent plate G is always constant from the upper end surface of the table. If you register the settings, you can change them with a single touch when changing the inspection type.
[0050]
Further, a belt-like linear light source 3 made of fiber is made to irradiate obliquely from below and close to the end surface of the transparent plate G, and the shielding plate 43 from the edge of the transparent plate G from below the transparent plate G. Since it is made to contact | abut in the position which protrudes slightly, the light by the linear light source 3 does not inject from other than the end surface of the transparent plate-shaped body G, and a defect can be detected accurately and stably.
[0051]
Further, the defect detection device 1 is provided in the middle of the line for transporting the transparent plate G, and the linear light source 3 that is illumination is freely raised and lowered, and is instantaneously raised and lowered at the start and end of inspection, and the end face of the transparent plate G As a result, the processing tact can be speeded up.
[0052]
As described above, the surface defects and internal defects of the transparent plate-like body G such as a glass plate, an acrylic resin plate, and a polycarbonate resin plate were detected. However, the present invention is not limited to this and can be applied to various transparent plate-like bodies. it can.
[0053]
The plate thickness of the transparent plate G can correspond to a plate thickness of 1 mm or less such as 0.55 mm or 0.7 mm to a plate thickness of several mm.
The defect detected as described above is further processed, and information such as the X-axis and Y-axis coordinate positions of the obtained defect is output and stored in a personal computer or the like, and in the subsequent process based on instruction control of the personal computer or the like. The glass including the part determined to be a defect can be removed or processed into various types of management information.
[0054]
【The invention's effect】
In the present invention, since the linear light source is a fiber light source, even a transparent plate having a very thin thickness can be reliably brought close to the end face and irradiated from the end face.
[0055]
In addition, since the linear light source can be raised and lowered by the lifting means, it is close to the end face of the transparent plate-like body only during the inspection, and after the inspection is completed, it is retracted immediately below the conveyor, so the transparent plate-like body Replacement is fast and complete inspection is possible with a fast tact.
[0056]
Further, even minute internal defects and surface defects of about 10 microns can be automatically and reliably detected at low cost, and are not affected by dirt, dust, dust, or the like attached to the transparent plate.
[0057]
Furthermore, since the transparent plate-like object is inspected in a floating state on the air table, and the conveyance is performed by holding and pressing the end surface edge of the transparent plate-like object, it is flat without being bent by its own weight. It can be inspected in the state, there is no false detection, and there is no fear of scratching or soiling the transparent plate-like body due to the inspection.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a main part of a defect detection apparatus of the present invention.
FIG. 2 is a luminance signal waveform captured by a line camera.
FIG. 3 is a side view of the defect detection apparatus of the present invention.
FIG. 4 is a plan view of the defect detection apparatus of the present invention.
FIG. 5 is a front view of the defect detection apparatus of the present invention.
FIG. 6 is a side view of the defect detection apparatus showing the inspection state of the transparent plate by raising the linear light source.
FIG. 7 is a side view of the defect detection apparatus showing a state of transporting a transparent plate by lowering a linear light source.
[Explanation of symbols]
G Transparent plate 1 Defect detection device 2 Defect 3 Linear light source 5 Line camera 6 Controller 7 Mounting base 10 Shield cover 10 Conveying means 11 Carrying conveyor 12 Air table 13 Carrying out conveyor 14 Driving roll 15 Driving motor 16 Driving belt 17 Floating conveyor 20 Positioning means 21 Pressing roll 22 Pressing lever 23 Pressing frame 24 Spring 25 Pressing position adjusting means 26 Adjusting means Traveling rail 30 Traveling means 32 Traveling rail 33 Traveling frame 40 Lifting means 41 Lifting cylinder 43 Shielding plate 44 Lifting member 45 Pushing roll 51 Image processing Device 52 PC

Claims (4)

Light is irradiated from one end face of the transparent plate that is carried on and positioned on the air table, and the surface of the transparent plate is scanned with a line camera provided above the transparent plate, and the obtained image signal is used. In the method for detecting defects in the transparent plate, the linear light source can be moved up and down, close to the end surface of the transparent plate only during inspection, and retracted slightly below the top of the conveyor when not inspected. and freely pass during unloading Jo body, a transparent plate-shaped object is totally reflected repeatedly between the front and back surfaces of the transparent plate-shaped object by irradiating said linear light source from the end face only, provided obliquely above the transparent plate-shaped object line While moving the camera at a constant speed in the horizontal direction perpendicular to the scanning direction of the camera, the entire surface of the transparent plate is imaged and scanned at an angle θ with respect to the normal of the transparent plate surface, and the luminance signal obtained is Pass / fail is determined at a predetermined level as a boundary Defect detection method of the transparent plate-shaped object, wherein the door.   Sensitivity correction is performed according to the distance between the linear light source irradiated from the end face of the transparent plate-like body and the scanning position of the traveling camera, so that the difference due to the distance from the light source is eliminated. The defect detection method for a transparent plate-like body according to claim 1. An air table for levitating the transparent plate-like body, a positioning means for carrying the floated transparent plate-like body by a carrying means and stopping the positioning at a predetermined position, and an end face close to one end surface of the transparent plate-like body and irradiating light from the end face A linear light source, a line camera that is provided obliquely above the transparent plate-like body surface, scans the transparent plate-like body surface in the width direction, traveling means that runs the line camera at a constant speed in the direction of transporting the transparent plate-like body, and imaging Ri Do predetermined level processes the luminance signal and a determination processing means for determining processing quality as a boundary, the belt-shaped light source formed of the linear light source from a plurality of optical fibers, transparent plate-shaped body that is positioned belt-like light source An apparatus for detecting defects in a transparent plate-like body, comprising elevating means for bringing light into the end surface of the transparent plate-like body and causing light to enter from the end face only in the inspection . Two opposing sides of the transparent plate-like body, a cylindrical pressing roller that makes contact with one end surface of the transparent plate-like object that floats on the air table and rotates freely, and a cylindrical drive roller that makes contact with the opposite end surface The defect detection device for a transparent plate-like body according to claim 3 , further comprising a conveying unit configured to convey the transparent plate-like body by rotating the driving roller.

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