JP5097993B2 - Light irradiation device - Google Patents

Description

  The present invention relates to a light irradiation apparatus capable of irradiating a surface to be observed of a polycrystalline panel such as a polycrystalline solar panel with uniform light.

  Conventionally, for example, when performing surface inspection of a product (work) having a glossy surface and inspection of the contents packed with a transparent glossy sheet, as shown in Patent Document 1, the surface to be observed (inspection surface) ) Is irradiated with substantially uniform light from all directions, so that the observation means such as a CCD camera is prevented from being reflected on the observation target surface, and the reflection unevenness due to the gentle unevenness of the observation target surface is also removed. It is known that only a scratch or the like can be clearly extracted as a change in contrast so that surface inspection can be automatically performed.

  However, some products are printed such as letters or pictures on the surface, and the color of the surface changes. In such a case, contrast caused by the color change is generated in the image picked up by the CCD camera, and it becomes difficult to distinguish it from the contrast caused by scratches or the like, which may cause a defect in the inspection.

  As what solves such a problem, as shown in Patent Document 2, a so-called dome-shaped light irradiation device is considered. As shown in the figure, the dome-shaped light irradiation device includes a casing having a semi-concave spherical reflection surface provided so as to surround the observation target surface from all directions other than the back surface, and toward the reflection surface. A first light source for irradiating light, and a second light source for irradiating light through a half mirror from a transparent window provided in the upper part of the casing, and imaging an observation target surface through the transparent window by an imaging means Is configured to do. The dome-shaped light irradiation device can cancel the contrast caused by the color change formed on the observation target surface, and can easily detect only scratches and the like.

  However, when imaging a polycrystalline panel such as a polycrystalline solar panel using the dome-shaped light irradiation device, the reflectance of each crystal grain is different, so the contrast caused by the color change is only canceled. Then, the density of crystal grains cannot be erased. In other words, the dome-type light irradiation device cannot cancel out the contrast caused by the difference in reflectance in the crystal grains.

Moreover, in order to image a large-sized polycrystalline solar panel, it is necessary to enlarge the casing so as to cover the entire surface to be observed. Further, in order to image the observation target surface, it is necessary to move the CCD camera away from the observation target surface as the observation target surface becomes larger due to the field of view (FOV) of the CCD camera. As a result, the field of view of the CCD camera is narrowed, so that only a small area can be imaged. Here, it is conceivable to enlarge the transparent window provided in the casing to an extent that does not obstruct the field of view of the CCD camera, but in this case, it is necessary to enlarge the half mirror and the second light source, and uniform light to the observation target surface. There is a problem that it becomes difficult to irradiate.
JP-T-08-510053 JP 2004-184241 A

  Therefore, the present invention has been made to solve the above problems all at once, canceling out the contrast caused by the difference in the reflection direction on the observation target surface that returns specularly reflected light having a different reflection direction depending on the irradiation site, and is large. The main intended task is to make it possible to detect scratches and the like on the observation target surface by irradiating the observation target surface of a uniform size with uniform light.

  That is, the light irradiation apparatus according to the present invention is a light irradiation apparatus that irradiates light with substantially uniform luminance from almost all directions on the observation direction side to an observation target surface that returns specular reflection light having different reflection directions depending on the irradiation site. A diffusion surface having a substantially frustoconical shape that is provided so as to substantially surround the observation target surface from substantially all directions on the observation direction side, and gradually expands toward the observation target surface; and A first light source unit that is provided on a substantially concentric circle and irradiates light toward the diffusion surface to make the luminance of the diffusion surface substantially uniform over the entire surface; and light having the same luminance as the luminance of the diffusion surface; A second light source unit that irradiates the observation target surface from an upper opening opposite to the observation target surface of the diffusion surface, and the first light source unit is arranged concentrically with respect to the diffusion surface. It has a plurality of LED rows, and the second light source unit is A plurality of LEDs provided substantially orthogonal to the central axis, a half mirror provided between the LEDs and the upper opening, and guiding the light of the LEDs to the observation target surface through the upper opening; and the LEDs And an imaging window for guiding the reflected light transmitted through the half mirror to an imaging means, and having an inner surface having a mirror surface.

  If it is such, while making the brightness | luminance of the diffusion surface provided so that it may surround substantially from substantially all directions of an observation object surface by a 1st light source part substantially uniform, opening of the opposite side to the observation object surface of a diffusion surface may be carried out. Since light having the same luminance as that of the diffusion surface is irradiated, contrast caused by the difference in reflection direction can be canceled out. Therefore, it is possible to clearly extract the contrast caused by only scratches or the like on the observation target surface that returns specularly reflected light having a different reflection direction depending on the irradiated part. Further, since the diffusing surface has a truncated conical shape, it is possible to easily irradiate light with uniform luminance onto a large observation target surface without increasing the size of the second light source unit. Furthermore, when the observation target surface is imaged by the imaging unit at the opening of the diffusion surface opposite to the observation target surface, the entire observation target surface can be captured without limiting the field of view of the imaging unit. Become. In addition, since the inner surface of the container is a mirror surface, the same effect can be obtained when the LED of the second light source section has a large area, so that the surface to be observed can be observed without causing enlargement and significant structural complexity. When the upper opening is viewed from, the area without the light emitting part can be reduced, and the luminance of almost the whole sky viewed from the observation target surface can be made more uniform.

  In order to simplify the construction of the diffusing surface and simplify the manufacture of the light irradiating device, it comprises a casing that forms the diffusing surface, and the casing is formed by forming a flat plate into a substantially cone shape. It is desirable.

  In order to suitably prevent the irradiation area from being limited by providing the first light source part inside the diffusion surface, the casing is formed from a light-transmitting flat plate, and the first light source part is It is desirable that the brightness of the diffusing surface be made substantially uniform over substantially the entire surface by irradiating light on substantially the entire outer peripheral surface of the casing, which is disposed outside the casing.

  In order to reduce the size of the first light source unit and to easily irradiate the outer peripheral surface of the casing with light, it is desirable that the first light source unit be concentrically arranged on the upper opening side of the diffusion surface.

  At this time, as a specific embodiment for making the luminance of the diffusion surface substantially the same, the first light source unit includes an upper irradiation unit that irradiates light on the upper half of the diffusion surface, and A lower irradiation unit that irradiates light to the lower half, and the LED of the upper irradiation unit is arranged substantially orthogonal to the central axis of the diffusion surface, and the LED of the lower irradiation unit is aligned with the central axis of the diffusion surface It is desirable to arrange along.

  Further, as a specific embodiment for irradiating light uniformly on the diffusion surface and making the luminance of the diffusion surface substantially the same, the LED columns of the first light source unit are independently adjusted for each column. It is desirable that the light is configured. More specifically, it is desirable that the angles formed by the optical axis of each LED row of the first light source unit and the central axis of the diffusion surface are different.

  For example, in order to acquire an image of the observation target surface and automatically detect scratches or the like by image processing, the substantially entire observation target surface is imaged from the opening of the diffusion surface opposite to the observation target surface. It is desirable to further include an imaging unit.

  In the case where the observation target surface is a light receiving surface of a polycrystalline panel, the present invention has a more remarkable effect. The polycrystalline panel is formed from a plurality of crystal grains, and each crystal grain has a different crystal direction, a different reflectance, and a contrast of light and shade occurs at the boundary of the crystal grain boundary. It is possible to prevent contrast caused by cracks and the like from being lost in contrast by crystal grains.

  As described above, according to the present invention, the contrast caused by the difference in the reflectance of each crystal grain is canceled on the observation surface forming the mirror surface of the polycrystalline panel, and the large-sized polycrystalline panel is irradiated with uniform light. This makes it possible to detect scratches on the surface to be observed.

  Next, an embodiment of a light irradiation apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing the light irradiation apparatus 100 of the present embodiment.

<Device configuration>
The light irradiation apparatus 100 according to this embodiment is an observation target that returns specularly reflected light having different reflection directions and reflectivities depending on the irradiated part, such as the surface (light receiving surface) of a polycrystalline panel such as a polycrystalline solar panel. A light irradiation device for a polycrystalline panel that irradiates the surface P with light of substantially uniform brightness from substantially all directions on the observation direction side. The imaging unit 500 images a predetermined irradiation region, and the obtained image data is It is used in a surface inspection system or the like that is taken into the image processing apparatus 600 and performs automatic surface inspection for the presence or absence of scratches or the like.

  Specifically, as shown in FIG. 1, this device includes a casing 2, a first light source unit 3 and a second light source unit 4 attached to the casing 2, and an imaging unit 500 such as a monochrome CCD camera as an observation unit. Can be attached.

  Hereinafter, each part 2-4 is explained in full detail.

  As shown in FIGS. 1 and 2, the casing 2 has a substantially cone shape in appearance, and has an opening 2 </ b> H at the top. A diffusion surface 2a having a substantially truncated cone shape that gradually expands toward the observation target surface P is formed on the inner surface thereof. The diffusion surface 2a is provided on the observation target surface P so as to be surrounded from almost all directions on the observation direction side. The casing 2 is formed by winding a light-transmitting flat plate.

  As shown in FIG. 1, the first light source unit 3 is provided substantially concentrically with the diffusion surface 2a, and irradiates light toward the diffusion surface 2a to make the luminance of the diffusion surface 2a substantially uniform over the entire surface. Is. A specific configuration is ring illumination having a plurality of LED arrays arranged concentrically with respect to the diffusion surface 2a.

  The first light source unit 3 of the present embodiment is arranged concentrically outside the casing 2 on the upper opening 2H side of the diffusion surface 2a, and irradiates light on substantially the entire outer peripheral surface of the casing 2. The brightness of the diffusing surface 2a is made substantially uniform over substantially the entire surface, and an upper irradiating portion 31 that irradiates light on substantially the upper half of the diffusing surface 2a (the outer peripheral surface of the casing 2), and the diffusing surface 2a (the casing 2). The lower irradiating section 32 irradiates light to the substantially lower half of the outer peripheral surface of the outer peripheral surface.

  As shown in FIGS. 1 and 3, the upper irradiation unit 31 is configured by ring illumination in which a plurality of LEDs 301 are provided so as to be substantially orthogonal to the central axis C of the diffusion surface 2 a. Specifically, a cylindrical substrate 311 in which the LED attachment surface 311a faces the central axis C of the diffusion surface 2a, and a plurality of attachments so that the LED attachment surface 311a of the substrate is substantially orthogonal to the central axis C of the diffusion surface 2a. The LED 301 is provided. The LEDs 301 are provided in a plurality of rows concentrically with respect to the central axis C of the diffusing surface 2a on the LED mounting surface 311a. The upper irradiation unit 31 is manufactured by, for example, disposing the LED 301 on a long substrate and then connecting both ends of the substrate. In addition, FIG. 3 is a figure which abbreviate | omitted electric wiring, and the broken line in a figure is for showing LED row | line | column, and LED located on a broken line comprises LED row | line | column.

  Moreover, the lower irradiation part 32 is comprised by the ring illumination by which LED301 was provided with two or more along the central axis C of the diffusion surface 2a, as shown in FIG.1 and FIG.4. Specifically, an annular substrate 321 with the LED attachment surface 321a facing the observation target surface P, and a plurality of LEDs 301 attached to the LED attachment surface 321a of the substrate 321 along the central axis C of the diffusion surface 2a, It is equipped with. The LEDs 301 are provided in a plurality of rows concentrically with respect to the central axis C of the diffusing surface 2a on the LED mounting surface 321a. Note that FIG. 4 is a diagram in which electrical wiring is omitted, and broken lines in the drawing are for indicating LED rows, and LEDs located on the broken lines constitute LED rows.

  The upper irradiation unit 31 and the lower irradiation unit 32 are fixed to the holding frame 33, and the holding frame 33 is fixed to the casing 2.

  Here, the angle formed by the optical axis of each LED column in each of the illumination units 31 and 32 and the central axis C of the diffusion surface 2a is made different for each column. Thereby, the light irradiated from each illumination part 31 and 32 can be irradiated to the outer peripheral surface of the casing 2 equally.

  And the light inject | emitted from these illumination parts 31 and 32 permeate | transmits the casing 2, is diffused by the diffusion surface 2a, and the diffused light is substantially uniform from each direction except the back side to each site | part of the observation object surface P. It is configured to be irradiated.

  Furthermore, the LED row | line | column of the 1st light source part 3 (each illumination part) of this embodiment is comprised so that light control is possible independently for the said row | line | column. Specifically, the amount of light of each LED row can be adjusted by adjusting the power supplied to each LED 301 by an LED control means (not shown) for each LED row.

  The second light source unit 4 is attached to the top of the casing 2 and emits light having the same luminance as that of the diffusion surface 2a from the upper opening 2H on the opposite side to the observation target surface P of the diffusion surface 2a. Is irradiated. A specific configuration includes an LED light source 41, a half mirror 42, and a housing 43 that houses and supports the LED 301 and the half mirror 42.

  The LED light source 41 is formed by arranging a plurality of LEDs 301 vertically and horizontally on a rectangular substrate 411. Further, the LED light source 41 is supported by a container 43 to be described later, and is provided so that the light emitting direction faces the central axis C of the diffusion surface 2a (casing 2). That is, each LED 301 is arranged so that its optical axis is substantially orthogonal to the central axis of the diffusion surface 2a, and irradiates light toward the half mirror 42 described later.

  The half mirror 42 is provided between the LED light source 41 and the upper opening 2H of the diffusing surface 2a, and guides the light of the LED light source 41 to the observation target surface P through the upper opening 2H. The half mirror 42 is supported by a container 43 described later, and is provided at an angle of 45 degrees with respect to the central axis C of the diffusing surface 2a.

  The accommodating body 43 has, for example, a rectangular parallelepiped hollow shape whose bottom is open, and is attached to the top of the casing 2. The container 43 supports the LED light source 41 in a standing state on the side thereof, supports a light diffusion plate 44 arranged in the light emission direction of the LED light source 41, and further directly above the upper opening 2H. The half mirror 42 disposed at an angle of 45 degrees is supported. The light emitted from the LED light source 41 is made uniform by the light diffusing plate 44, further reflected by the half mirror 42, passed through the upper opening 2H, and irradiated onto the observation target surface P from above. It is.

  Further, the container 43 is provided with an imaging window 431 for photographing the observation target plane P by the imaging means 500 on the top plate. The imaging window 431 is positioned immediately above the upper opening 2H, and is configured such that the imaging surface of the imaging means 500 attached thereto faces the observation target surface P through the half mirror 42 and the upper opening 2H. ing. Thereby, the imaging means 500 receives the reflected light that has passed through the upper opening 2H and the half mirror 42.

  Furthermore, the inner surface of the container 43 is a mirror surface. That is, the entire surface covering the upper opening 2H of the diffusion plate 2a is made to be a mirror surface. Thereby, since the same effect as the LED light source 41 having a large area can be obtained, there is no light emitting portion when the upper opening 2H is viewed from the observation target surface P without causing enlargement and significant structural complexity. The area can be reduced, and the luminance of almost the whole sky as viewed from the observation target surface P can be made more uniform.

  Thus, the irradiation light diffused on the diffusion surface 2a and the irradiation light entering from the upper opening 2H are uniform in all directions from substantially the whole sky above the horizontal line as viewed from the observation target surface P. It is configured to irradiate light with a high luminance.

<Effect of this embodiment>
According to the light irradiation device 100 according to the present embodiment configured as described above, the luminance of the diffusion surface 2a provided so as to be substantially surrounded by the first light source unit 3 from substantially all directions of the observation target surface P is substantially uniform. Since light having the same luminance as the luminance of the diffusing surface 2a is emitted from the opening opposite to the observation target surface P of the diffusing surface 2a, the contrast caused by the difference in the reflection direction can be canceled out. Therefore, it is possible to clearly extract the contrast caused by only scratches or the like on the observation target surface P that returns specularly reflected light having different reflection directions and reflectivities depending on the irradiation site. Further, since the diffusing surface 2a has a truncated conical shape, it is possible to easily irradiate light of uniform brightness onto the observation target surface P having a large size without increasing the size of the second light source unit 4. Further, when the observation target surface P is imaged by the imaging unit 500 at the opening of the diffusion surface 2a opposite to the observation target surface P, the entire observation target surface P is captured without limiting the field of view of the imaging unit 500. Will be able to.

<Other modified embodiments>
The present invention is not limited to the above embodiment. In the following description, the same reference numerals are given to members corresponding to the above-described embodiment.

  For example, in addition to the configuration of the first light source unit 3 of the above embodiment, as shown in FIG. 5, the casing is interposed via a fixing member (not shown) so as to protrude inward in the vicinity of the lower opening of the casing 2. And a plurality of LEDs 301 attached to the substrate 33 so as to face the upper opening 2H along the central axis C of the diffusion surface 2a.

  Further, as shown in FIG. 6, the upper irradiation part 31 is arranged concentrically on the outer opening 2H side of the diffusion surface 2a on the outer side of the casing 2, and the upper irradiation part 31 is substantially above the outer peripheral surface of the casing 2. Light is irradiated to the half, and the lower irradiation part 32 is disposed so as to protrude inward in the vicinity of the lower opening of the casing 2 so that the lower irradiation part 32 irradiates light to the substantially lower half of the diffusion surface 2a. Anyway.

  In addition, some or all of the above-described embodiments and modified embodiments may be combined as appropriate, and the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. .

The schematic block diagram which shows the light irradiation image apparatus of this embodiment. The perspective view of the casing of the embodiment. The figure which shows the board | substrate and LED of the upper irradiation part of the embodiment. The figure which shows the board | substrate and LED of the lower irradiation part of the embodiment. The schematic block diagram of the light irradiation apparatus which concerns on deformation | transformation embodiment. The schematic block diagram of the light irradiation apparatus which concerns on deformation | transformation embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Light irradiation apparatus P ... Observation object surface 2a ... Diffusion surface 3 ... 1st light source part 2H ... Upper opening 4 ... 2nd light source part 301 ... LED
42 ... half mirror 43 ... container 431 ... imaging window 2 ... casing 31 ... upper irradiation part 32 ... lower irradiation part C ... central axis of diffusing surface 2a (casing 2 Center axis C)

Claims (9)

A light irradiation device that irradiates light with substantially uniform brightness from substantially all directions on the observation direction side to an observation target surface that returns specularly reflected light having different reflection directions depending on the irradiation site,
A diffusion surface having a substantially truncated cone shape that is provided so as to substantially surround the observation target surface from substantially all directions on the observation direction side, and gradually expands toward the observation target surface;
A first light source unit that is provided substantially concentrically with the diffusion surface, irradiates light toward the diffusion surface, and makes the luminance of the diffusion surface substantially uniform over the entire surface;
A second light source unit configured to irradiate the observation target surface with light having the same luminance as the luminance of the diffusion surface from an upper opening opposite to the observation target surface of the diffusion surface;
The first light source unit has a plurality of LED rows arranged concentrically with respect to the diffusion surface, and an upper irradiation unit that irradiates light on the upper half of the diffusion surface; and the diffusion surface It consists of a lower irradiation part that irradiates light to the lower half of the
The second light source unit is provided between a plurality of LEDs provided substantially orthogonal to the central axis of the diffusion surface and between the LEDs and the upper opening, and the light from the LEDs passes through the upper opening. Light that includes a half mirror that leads to an observation target surface, an LED that houses the LED and the half mirror, an imaging window that guides reflected light that has passed through the half mirror, to an imaging unit, and an inner surface that has a mirror surface. Irradiation device.   The light irradiation apparatus according to claim 1, further comprising a casing that forms the diffusion surface on an inner surface, wherein the casing is formed by forming a flat plate into a substantially cone shape. The casing is formed from a light-transmitting flat plate;
The said 1st light source part is arrange | positioned on the outer side of the said casing, and irradiates light to the substantially whole outer peripheral surface of the said casing, The brightness | luminance of the said diffusion surface is made substantially uniform in the substantially whole surface. Light irradiation device.   The light irradiation apparatus according to claim 3, wherein the first light source unit is arranged concentrically on the upper opening side of the diffusion surface. The light irradiation apparatus according to claim 4, wherein the LEDs of the upper irradiation unit are arranged substantially orthogonal to the central axis of the diffusion surface, and the LEDs of the lower irradiation unit are arranged along the central axis of the diffusion surface.   The light irradiation device according to claim 1, wherein the LED row of the first light source unit is configured to be dimmable independently for each row.   The light irradiation device according to claim 1, 2, 3, 4, 5 or 6, wherein the angle formed between the optical axis of each LED row of the first light source unit and the central axis of the diffusion surface is different.   The light irradiation apparatus according to claim 1, 2, 3, 4, 5, 6 or 7, further comprising imaging means for imaging substantially the entire surface to be observed from the imaging window.   The light irradiation apparatus according to claim 1, wherein the observation target surface is a polycrystalline panel.