JP2014098594A - Led illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED illumination device used for photographing a defect for defect detection, which has no limit in a longer direction, has a simple structure, and further improves sensitivity in defect detection compared with the conventional art.SOLUTION: A plurality of LED light-emitting elements are aligned linearly along a longer direction of openings which are formed along a longer direction on one outer wall surface of the longer direction of a slender casing. Slender reflective flat plates are respectively arranged at both sides of the aligned LED light-emitting elements, so as to be along the longer direction of the openings, be orthogonal to the openings and reach the opening side from the aligned LED light-emitting element side. Emission light from the LED light-emitting elements is directly guided or reflected by the reflective flat plate arranged at both sides of the aligned LED light-emitting elements to the opening side. The emission light passing through the openings serves as illumination light for linearly illuminating the surface of a plate-like object.

Description

  The present invention relates to an LED lighting device, and more particularly to a structure of an LED lighting device for illumination used for photographing a surface of a plate-like object for detecting a defect on the surface of the plate-like object.

In recent years, LED lighting devices have come to be used for reasons such as low power consumption, long life, low noise, and high brightness.
Under such circumstances, an elongated LED illumination device 110 as shown in FIG. 4 that illuminates in a line shape has come to be used in photographing for detecting a concave defect (scratch defect) on the surface of a plate-like object. It was.
As for the imaging | photography for the detection of the recessed part defect of the surface of the plate-shaped object 120, as shown in FIG. 4, while conveying the plate-shaped object 120, the surface of the plate-shaped object 120 is line-shaped with the LED illumination device 110 normally. The image data of the surface of the plate-like object 120 is obtained by photographing with a camera using a solid-state imaging device as an image sensor, and performing data processing using the image data obtained by photographing, Defect detection.
3A is a schematic view of the appearance of the elongated LED illumination device 110 shown in FIG. 4 with the outgoing light side facing upward, and FIG. 3B is the LED illumination shown in FIG. FIG. 3C is a cross-sectional view in a direction orthogonal to the longitudinal direction of the device 110, and FIG. 3C is a schematic cross-sectional view as viewed in the direction of the arrow from B1-B2 in FIG.
Moreover, the thick dotted line arrow of FIG.3 (b) has shown the emitted light.
As shown in FIG. 3C, the LED illumination device 110 shown in FIG. 4 has a plurality of LED light emitting elements 112 arranged linearly along the longitudinal direction so as to cover the entire LED light emitting elements 112 arranged. 3B is provided with a cylindrical rod lens 115 having a circular cross section, and the light emitted from the LED light emitting element 112 is condensed through the rod lens 115 and emitted through the diffusion plate 116. Is.
The LED light emitting elements 112 are arranged on the printed circuit board 113, and the printed circuit board 113, the LED light emitting elements 112, and the rod lens 115 all have an opening 111S on the opposite side of the rod lens 115 from the LED light emitting element 112 side. Surrounded by the provided aluminum casing 111, the opening 111 </ b> S of the casing 111 is closed by a diffusion plate 116.
The rod lens 115 prevents the light emitted from the LED light emitting element 112 from being irregularly reflected on each surface of the housing 111, and the diffuser plate 116 emits the diffused light.
Heat dissipation grease 114 is coated between the printed circuit board 113 and the bottom surface 111b of the casing 111 and is heated by the LED light emitting element 112, but heat is transferred from the printed circuit board 113 to the casing 111 side through the heat dissipation grease 114. The heat is dissipated.

However, as shown in FIG. 3B, the conventionally used LED lighting device 110 uses a rod lens 115, so that the length is limited, and the rod lens itself is expensive. Was a problem.
Furthermore, as shown in FIG. 3B, the LED illumination device 110 that has been used conventionally emits light through the diffusion plate 116, but the light emitted from B0 in FIG. In general, the intensity distribution has an intensity distribution in which the light intensity is maximized in a direction orthogonal to the diffusion plate 116 and concentrated in a direction near the direction to increase the light intensity. When used as an illuminating device that illuminates in the form of a line in photographing for detecting a concave defect (scratch defect) on the surface, it passes through B0 shown in FIG. The intensity of the emitted light is large, and the emitted light in this direction and a predetermined direction close to this direction mainly works as illumination light.
In FIG. 4, the emitted light in the predetermined direction is indicated by a thick dotted arrow.
Therefore, as shown in FIG. 4, using the LED illumination device 110, the plate-like object 120 is detected by the camera 130 while the plate-like object 120 to be detected as a recess defect (scratch defect) is conveyed in a predetermined direction. In the conventional defect detection method of photographing a surface and processing the captured image data obtained by the photographing to detect a concave defect (scratch defect) on the surface of the plate-like object 120, a concave defect (scratch defect) ) Is an elongated recess defect (scratch defect) along the conveying direction of the plate-like object 120, the illumination light irradiated to the side surface side of the recess defect (scratch defect) is small during photographing, and the plate-like object The detection sensitivity of the recess defect (scratch defect) in the conveyance direction 120 is low, which is a problem.

JP 2009-20474 A

As described above, in recent years, the use of LED illuminating devices has become popular, and LEDs that illuminate in a line shape using a rod lens as shown in FIG. 3 also in photographing for detecting defects of concave defects on the surface of a plate-like object. Although lighting devices have come to be used, there is a limitation in the length direction, the rod lens itself is expensive, there is no limitation in the length direction, and a simple structure is required.
Furthermore, while conveying the target plate-like object in a predetermined direction, the image is illuminated by the LED illumination device that illuminates in a line shape, and the imaging device (also referred to as a camera) using a solid-state imaging device as an image sensor. In the defect detection, the surface of the plate-like object is photographed, data processing is performed using the obtained captured image data, and the depression defect on the surface of the plate-like object is detected. The detection sensitivity is low, and this is a problem, and countermeasures have been demanded.
The present invention is intended to provide an LED lighting device having a simple structure with no limitation in the length direction. Further, the present invention illuminates with an LED lighting device that illuminates in a line shape. The surface of the plate-like object is photographed by an image pickup device (camera) using a solid-state image sensor as an image sensor, and data processing is performed using the obtained captured image data to detect a concave defect on the surface of the plate-like object. An object of the present invention is to provide an LED illumination device capable of increasing the detection sensitivity of a recess defect in a plate-shaped object conveyance direction as compared with a case where a conventional LED illumination device is used in defect detection.

The LED illumination device of the present invention photographs the surface of the plate-like object with the imaging device while relatively moving the plate-like object in a predetermined direction with respect to the imaging device using the solid-state imaging device. Then, data processing is performed using captured image data obtained by photographing, and the surface of the plate-like object used at the time of photographing in the defect detection method for detecting a concave defect on the surface of the plate-like object. LED lighting device that illuminates a light source in a line shape, and is opposed to the outer wall surface where the opening is located within the elongated housing and an opening formed along the longitudinal direction on one outer wall surface in the longitudinal direction. A plurality of LED light-emitting elements are arranged in a line along the longitudinal direction of the opening on a printed circuit board supported via heat-dissipating grease on the outer wall surface of the housing on the side to be mounted, at a position facing the opening. Yes, the arranged LEDs Reflective flat plates are arranged on both sides of the optical element, respectively, along the longitudinal direction of the opening and perpendicular to the opening, from the arrayed LED light emitting element side to the opening side, The emitted light from the LED light emitting element is reflected directly or by the reflective flat plates on both sides of the arranged LED light emitting elements to reach the opening side, and the emitted light passing through the opening is reflected in the plate shape. The illumination light illuminates the surface of the object in a line shape.
Here, the direction orthogonal to the opening means a direction orthogonal to the opening region along the outer wall surface defined by the outer wall surface forming the opening.
Here, relative movement means fixing the position of the imaging device and the LED lighting device to move the plate-like object, or fixing the position of the plate-like object to integrate the imaging device and the LED lighting device. This means that the plate-like object is moved relative to the imaging device and the LED lighting device.
And it is said LED illuminating device, Comprising: The reflective flat plate of the both sides of the said arrayed LED light emitting element consists of an aluminum plate, A micro unevenness | corrugation is provided in the surface of the said aluminum plate. It is characterized by that.
Moreover, it is one of said LED illuminating devices, Comprising: The said plate-shaped object is a glass substrate, It is characterized by the above-mentioned.

(Function)
The LED illumination device of the present invention is intended to provide an LED illumination device having a simple structure with no limitation in the length direction by adopting such a configuration, and further, LED illumination that illuminates in a line shape. The surface of the plate-like object is photographed with an imaging device that uses a solid-state imaging device as an image sensor, and data processing is performed using the obtained captured image data. It is possible to provide an LED illuminating device capable of increasing the detection sensitivity of a concave defect in the conveying direction of a plate-like object in the defect detection for detecting the defect as compared with the case where a conventional LED illuminating device is used.
Specifically, in the case of a long and slender casing and an opening formed along the longitudinal direction on one outer wall surface in the longitudinal direction, the outer wall surface of the casing facing the outer wall surface where the opening is located. A plurality of LED light emitting elements are arranged in a line along the longitudinal direction of the opening at a position facing the opening on a printed circuit board supported via heat radiation grease. Reflective flat plates extending from the arranged LED light emitting element side to the opening side along the longitudinal direction of the opening and perpendicular to the opening are arranged on both sides of the LED, respectively. The emitted light from the element is reflected directly or by the reflective flat plates on both sides of the LED light emitting elements arranged so as to reach the opening side, and the emitted light passing through the opening is reflected on the plate-like object. Line surface By it is an illumination light for illuminating, we have achieved this.
Usually, the casing has a quadrangular cross-sectional shape in the direction perpendicular to the longitudinal direction, but the outer wall surface for forming the opening and the outer wall surface for disposing the organic EL light emitting element on the side facing the outer wall surface The cross section may be a trapezoidal shape in some cases.
In particular, on both sides of the arrayed LED light emitting elements, a reflective flat plate extending from the arrayed LED light emitting element side to the opening side is disposed along the longitudinal direction of the opening and perpendicular to the opening. The emitted light from the LED light emitting element is reflected directly or by the reflective plates on both sides of the arranged LED light emitting elements to reach the opening side, and the emitted light that has passed through the opening By using illumination light that illuminates the surface of the plate-like object in a line shape, the structure is simple without being limited by the length of the rod lens as in a conventional illumination device using a rod lens. And the surface of the plate-like object to be inspected can be irradiated from various directions.
For concave defects along the transport direction, it is possible to increase the amount of light that hits from the side of the concave defect compared to conventional illumination devices using rod lenses, and illumination using conventional rod lenses In the defect detection by illumination by the apparatus, it is possible to clearly image even a defect for which it was difficult to image a defective part by data processing.
The reflective flat plates on both sides of the arrayed LED light emitting elements are not particularly limited as long as they are suitable for application to a lighting device, and various surface reflective metal plates and reflective metal layers on the surface are provided. Although the arranged board | plate material is used, especially an aluminum board is preferable from surfaces, such as reflectivity, workability, tolerance.
In addition, when the surface of the aluminum plate is provided with minute irregularities, it can improve the scattering property in the reflection of the surface of the aluminum plate, and it can be inspected from various directions as compared with the illumination device using the conventional rod lens. It is assumed that the surface of the target plate-like object can be irradiated.

Conventionally, detection of a concave defect on the surface of a plate-like object is performed by illuminating the concave defect with an LED illumination device 110 using a fluorescent lamp that can be illuminated in a line shape or a rod lens shown in FIGS. Then, using the obtained image data, the difference in reflectance from the non-defective part was obtained as image information for defect detection, and then image processing was performed to extract the recessed defect part as an image. For concave defects in the direction (121 in FIG. 4), the sensitivity of detection is low in photographing with an LED illumination device using a fluorescent lamp that irradiates in a line or a rod lens shown in FIGS. It was difficult to extract as.
The LED illuminating device that can illuminate in a line shape of the present invention is provided with reflective flat plates on both sides of the arranged LED light emitting elements with respect to the concave defect in the shape along the transport direction, and the emitted light from the light source is Since the reflected light is reflected on both sides of the arrayed LED light emitting elements and passes through the opening to become illumination light, the object to be inspected from various directions as compared with illumination by an illumination device using a conventional rod lens. It is assumed that the surface of the plate can be irradiated.
Therefore, the LED illuminating device capable of illuminating in a line shape according to the present invention can increase the amount of light hitting from the side as compared with the illumination of the LED illuminating device using the conventional rod lens shown in FIGS. As a result, the sensitivity of defect detection can be improved.
In particular, when an aluminum plate is used as the reflective flat plate on both sides of the arrayed LED light emitting elements and the surface is uneven, the scattering can be increased in the reflection of the surface. As compared with the illumination of the LED illumination device using the conventional rod lens shown in FIG. 2, the amount of light hit from the side surface side can be further increased, and as a result, the sensitivity of defect detection can be improved. Examples of the method for forming irregularities on the aluminum plate include a polishing method using abrasive grains and an electrolytic polishing method.

  When the plate-like object is a glass substrate, the conventional LED device using the rod lens shown in FIG. 3 is difficult to detect, and the plate-like object moves when photographing the surface of the plate-like object in defect detection. An elongated recess defect (scratch defect) along the direction can also be detected, which is particularly effective for such defect detection.

Note that, when the surface of the plate-like object is photographed in the defect detection, an elongated recess defect (scratch defect) along the direction of movement of the plate-like object occurs, for example, as follows.
In manufacturing a color filter used in a display device on a glass substrate, as shown in FIG. 5A, there is a step of coating a colored resin layer 230 on the surface of the glass substrate 210 by a die coating method. When a coating film is formed with the foreign matter 240 being bitten between the head 220 and the glass substrate 210, the surface of the glass substrate may be scratched by the foreign matter, and scratches may occur.
On the other hand, as shown in FIG. 5B, the rear surface of the glass substrate 210 is conveyed when an abnormality occurs in a part of the rollers 263 of the roller conveyor that conveys the glass substrate 210 and rotation is awkward. Since the glass substrate 210 and the roller 263 are rubbed, scratches may occur in the transport direction.
Illumination by the LED illumination device of the present invention is particularly suitable for inspection of scratches that enter the direction in which the glass substrate 210 is conveyed.

  As described above, the present invention makes it possible to provide an LED illumination device having a simple structure with no limitation in the length direction, and further, the LED illumination device that illuminates in a line shape is used as a solid image sensor. In defect detection, the surface of a plate-like object is photographed by an imaging device (camera) using an image pickup device, data processing is performed using the obtained captured image data, and a concave defect on the plate-like object surface is detected. Compared to the case where a conventional LED illumination device using a lens is used, it is possible to provide a new LED illumination device capable of increasing the detection sensitivity of the concave defect in the conveyance direction of the plate-like object.

Fig.1 (a) is the perspective view which showed the external appearance of one example of the LED lighting apparatus of this invention, FIG.1 (b) shows the cross section orthogonal to the longitudinal direction of the LED lighting apparatus shown to Fig.1 (a). FIG. 1C is a diagram showing a schematic configuration of an imaging method for defect detection using the LED illumination device shown in FIG. FIG. 2A is a view seen in the direction of the arrow in A1-A2 of FIG. 1B, and FIG. 2B is a light emission emitted from the LED light emitting element in the direction along the longitudinal direction of the opening. FIG. 2C is a schematic diagram showing light, and FIG. 2C is a schematic diagram showing emitted light emitted from the LED light emitting element in the cross section of FIG. FIG. 3A is a perspective view showing an appearance of an example of a conventional LED lighting device, and FIG. 3B shows a cross section orthogonal to the longitudinal direction of the LED lighting device shown in FIG. FIG. 3C is a diagram seen from the B1-B2 cross section of FIG. 3B in the direction of the arrow. It is the figure which showed schematic structure of the imaging | photography method for the defect detection using the conventional LED illuminating device shown in FIG. FIG. 5 (a) is a diagram for explaining the occurrence of a concave defect (scratch defect) when a colored resin layer is coated on one surface of a glass substrate by a die coater, and FIG. It is a figure for demonstrating generation | occurrence | production of the recessed part defect at the time of roller conveyance.

First, one example of the LED lighting device of the present invention will be described with reference to FIG.
As shown in FIG. 1C, the LED illumination device 10 of this example moves the plate-like object 20 in a predetermined direction relative to the imaging device 30 using a solid-state imaging element, while After imaging the surface of the plate-like object 20 with the imaging device 30, data processing is performed using the captured image data obtained by the imaging to detect a concave defect (scratch defect) on the surface of the plate-like object 20. In the defect detection method, the LED illumination device illuminates the surface of the plate-like object 20 used in the photographing in a line shape.
The LED lighting device of this example is an elongated casing as shown in FIG. 1 (a), and is illuminated from an opening 11S of the casing 11 having an opening 11S along the longitudinal direction on one outer wall surface 11a in the longitudinal direction. It irradiates light.
As shown in FIG. 1 (b), on the printed circuit board 13 supported on the outer wall surface 11b of the housing on the side facing the outer wall surface 11a with the opening 11S inside the housing 11, via the heat radiation grease 14, A plurality of LED light emitting elements 12 are arranged in a line shape, and the arrangement is arranged on both sides of the arranged LED light emitting elements 12 along the longitudinal direction of the opening 11S and perpendicular to the opening 11S. An elongated reflective flat plate 16 is arranged in the row direction of the arranged LED light emitting elements 12 from the LED light emitting element 12 side to the opening 11S side.
Then, the emitted light 12L from the LED light emitting element 12 is reflected directly or by the reflective flat plates 16 on both sides of the LED light emitting elements 12 arranged so as to reach the opening 11S side, and the opening 11S is formed. The emitted light that has passed is used as illumination light that illuminates the surface of the plate-like object 20 in a line.

In the LED lighting device of this example, the emitted light from the LED light emitting element 12 is reflected directly or by the reflective flat plates 16 on both sides of the arranged LED light emitting elements 12, and proceeds to the diffusion plate 15 to diffuse. The light passes through the plate 15, passes through the opening 11 </ b> S, is emitted, and becomes illumination light.
All of the emitted light emitted from the LED light emitting elements reaches the diffusion plate 15.
Then, the light passes through the diffusion plate 15, passes through the opening 11 </ b> S, and becomes illumination light that illuminates the surface of the plate-like object 20 in a line shape.
As shown in FIG. 2B, the emitted light emitted from the LED light emitting element in the direction along the longitudinal direction of the opening 11S proceeds in the emitted direction to the diffusion plate 15, passes through the diffusion plate 15, The light is emitted through the opening 11S and becomes illumination light.
However, this does not apply to the emitted light emitted at both ends in the longitudinal direction of the opening 11S.
In addition, as shown in FIG. 2C, in the cross section orthogonal to the longitudinal direction of the housing of the LED lighting device, the emitted light emitted from the LED light emitting element traveling in the direction of the reflective flat plate 16 is reflected. After being reflected by the surface of the flat plate 16 and reaching the diffusion plate 15, it passes through the diffusion plate 15, passes through the opening 11S, and is emitted to become illumination light.
In this example, the cross-sectional shape in the direction orthogonal to the longitudinal direction of the housing 11 is a quadrangular shape.

In this example, as shown in FIG. 2B, the emitted light 12L from the LED light emitting elements 12 is dispersed and emitted in the direction along the arrangement direction of the LED light emitting elements 12, but is dispersed in that direction. The emitted light 12L reaches the diffusion plate 15, is further dispersed in each direction in the diffusion plate 15, and the light that has passed through the diffusion plate 15 reaches the opening 11S side.
In this way, most of the emitted light 12L dispersed and emitted from the LED light emitting element 12 in the direction along the arrangement direction of the LED light emitting elements 12 is effectively used as illumination light.
On the other hand, in the case of the illumination device using the conventional rod lens shown in FIGS. 3 and 4, the emitted light is emitted from the LED light emitting elements 12 while being dispersed in the direction along the arrangement direction of the LED light emitting elements 12. As for, part of the light is totally reflected by the rod lens, and even if it is incident on the rod lens, part of the light is pre-reflected without being emitted from the rod lens.
Therefore, in the case of this example, the illumination light in the direction along the arrangement direction of the LED light emitting elements 12 can be increased as compared with the case of the illumination device using the conventional rod lens shown in FIG. 3 and FIG. A recess defect (scratch defect) 21 (corresponding to the recess defect 121 in FIG. 4) along the conveyance direction shown in (c) is compared with the case of the illumination device using the conventional rod lens shown in FIGS. It is assumed that it is easy to detect.
In addition, as shown in FIG. 2C, the emitted light 12L from the LED light emitting element 12 is dispersed and emitted in a direction orthogonal to the direction along the arrangement direction of the LED light emitting elements 12, but dispersed in this direction. The emitted light 12L is reflected directly or by the reflective flat plate 16 arranged on both sides of the LED light emitting element 12, reaches the diffusion plate 15, and is further dispersed in each direction in the diffusion plate 15. The light that has passed through the diffusion plate 15 reaches the opening 11S side.
As described above, since the light is efficiently emitted in the direction along the arrangement direction of the LED light emitting elements 12 and also in the direction orthogonal to the arrangement direction of the LED light emitting elements 12, it becomes illumination light. In addition to the recess defect 21 along the transport direction shown in FIG. 2, the defect detection of the recess defect 22 in the direction orthogonal to the transport direction is possible.
This is because the oblique light effective for defect detection in the direction orthogonal to the transport direction is larger than that in the case of the illumination device using the conventional rod lens shown in FIGS.

  In the case where an aluminum plate is used as the reflective flat plate on both sides of the arranged LED light emitting elements and the surface thereof is uneven, the scattering can be increased in the reflection of the surface. As compared with the illumination of the LED illumination device using the conventional rod lens shown in FIG. 2, the amount of light hit from the side surface side can be further increased, and as a result, the sensitivity of defect detection can be improved.

The material of each part will be briefly described.
<Housing 11>
The material is not particularly limited as long as it is strong, has good heat dissipation, is light, and can be easily manufactured, but usually an aluminum material is used.
<LED light emitting element 12>
A commercially available LED chip structure in which a P-type semiconductor and an N-type semiconductor are joined may be arranged as an LED light-emitting element, and an organic LED element (organic EL) can be obtained if the desired brightness can be obtained. May be arranged in a predetermined shape as an LED light emitting element.
As the LED light-emitting element used here, brightness is emphasized, and in the LED chip structure, a bright type LED light-emitting element called “power LED” is used rather than a conventional bullet-type LED light-emitting element. To do.
When white light is used as illumination light, the light emission colors of R, G, and B may be mixed to produce white light emission.
Alternatively, blue light emitted from a blue light emitting LED and phosphors that emit red and green light (also referred to as conversion layers) when irradiated with the blue light emitted, respectively, blue light and red light are emitted. Light and green light may be obtained and mixed together to produce white light.
<Heat dissipation grease 14>
It is preferable that the printed board 13 can be fixed sufficiently, has good heat dissipation, is easy to use, has heat resistance, and exhibits stable characteristics even at high temperatures.
For example, there is silicone grease, but it is not limited to this.
Usually, the heat release grease is mainly silicone, and metal particles such as silver are mixed to improve performance.
<Printed circuit board 13>
The printed board 13 is preferably one having excellent wiring properties, circuit functions, resistance, etc., but is not particularly limited.
As the base material, one or more of a glass epoxy substrate, a glass polyimide substrate, a fluorine substrate, a glass PPO substrate, a metal substrate, a ceramic substrate, and the like may be used as appropriate.
In addition, when the conventional relatively dark LED light emitting element is used, the above epoxy substrate or the like is also used, but basically, since an LED light emitting element called “power LED” is used in order to obtain brightness, Heat becomes a problem, and metal substrates with high heat dissipation performance (metal substrates such as aluminum and copper) are used.
<Reflective flat plate 16>
As the reflective flat plate 16, a surface having a reflective, strong, light, good workability, and good heat dissipation property is preferable, and an aluminum plate is suitable in terms of quality and production.
In addition, an aluminum plate is normally produced by the rolling method and the extrusion method, and can obtain the thing of desired length and width.
Moreover, in the case of an aluminum plate, the surface can be made uneven by a polishing method using abrasive grains or an electrolytic polishing method to improve the scattering property at the time of reflection.

The present invention is not limited to the above form.
In the LED lighting device shown in FIG. 1, a form in which a diffusion plate is not arranged in the opening 11 </ b> S is also included.
Further, in the LED lighting device shown in FIG. 1, the casing 11 has a quadrangular cross-sectional shape in the direction orthogonal to the longitudinal direction, but on the outer wall surface forming the opening and the side facing the outer wall surface. It suffices to have an outer wall surface for arranging the organic EL light emitting element, and in some cases, the cross section may be a trapezoidal shape.

DESCRIPTION OF SYMBOLS 10 LED illuminating device 10L Outgoing light 11 Housing 11S Opening 11a (opening side) outer wall surface 11b Outer wall surface 11c, 11d Outer wall surface 12 LED light emitting element 12L Emitted light 13 Printed board 14 Radiation grease 15 Diffusion plate 16 Flat plate 20 Plate-like object 21 Recess defect (also called scratch defect)
22 Recess defect (also called scratch defect)
30 Imaging device (also called camera)
30S imaging region 110 LED illumination device 110L illumination light 111 housing 111S opening 111a (on the opening side) outer wall surface 111b outer wall surface 112 LED light emitting element 113 printed circuit board 114 heat dissipation grease 115 rod lens 116 diffuser plate 110 LED illumination device 120 plate-like object 121 , 122 Recess defect (also called scratch defect)
130 Imaging device (also called camera)
130S imaging region 210 glass substrate 220 die coater head 230 colored resin layer 240 foreign matter 250 stage (also called mounting table)
261-264 Rollers (of conveyor)

Claims (4)

  Obtained by photographing after imaging the surface of the plate-like object with the imaging device while relatively moving the plate-like object in a predetermined direction with respect to the imaging device using the solid-state imaging element. LED illumination that illuminates the surface of the plate-like object used in the photographing in a line form in a defect detection method that performs data processing using the captured image data and detects a concave defect on the surface of the plate-like object A device having an elongated casing and having an opening formed along the longitudinal direction on one outer wall surface in the longitudinal direction, the outer wall surface of the casing facing the outer wall surface with the opening. A plurality of LED light emitting elements are arranged in a line along the longitudinal direction of the opening at a position facing the opening on a printed circuit board supported via heat radiation grease. On both sides, respectively A reflective flat plate is provided along the longitudinal direction of the opening and perpendicular to the opening, from the arranged LED light emitting element side to the opening side, and emits light emitted from the LED light emitting element. Directly or by reflecting on the reflective flat plates on both sides of the arrayed LED light emitting elements to reach the opening side, the surface of the plate-like object is illuminated in a line with the emitted light passing through the opening An LED illumination device characterized in that the illumination light is used.   2. The LED lighting device according to claim 1, wherein the reflective flat plates on both sides of the arranged LED light emitting elements are made of an aluminum plate.   3. The LED lighting device according to claim 2, wherein minute unevenness is provided on the surface of the aluminum plate.   4. The LED lighting device according to claim 1, wherein the plate-like object is a glass substrate. 5.

Images