WO2019208752A1

WO2019208752A1 - Light radiating device

Info

Publication number: WO2019208752A1
Application number: PCT/JP2019/017849
Authority: WO
Inventors: 顕治櫻井; 篤史宮武
Original assignee: シーシーエス株式会社
Priority date: 2018-04-27
Filing date: 2019-04-26
Publication date: 2019-10-31
Also published as: JP7157799B2; JPWO2019208752A1

Abstract

Provided is a light radiating device with which light losses are small and which is capable of radiating light efficiently toward a workpiece, and with which unevenness of light is small when viewed as an entire light-guiding plate. This light radiating device is provided with a light source, and a light-guiding plate which has a plate shape with a top surface, a rear surface, and a side peripheral surface, in which the top surface is disposed facing a workpiece to be inspected, and light from the light source is guided in from the side peripheral surface, the light radiating device being configured in such a way that light guided into the light-guiding plate from the side peripheral surface is internally reflected and is emitted from the top surface, wherein: the light radiating device is additionally provided with a cover body which is disposed in such a way as to cover the rear surface of the light-guiding plate, and in which a through hole is provided in a prescribed location; a diffuse reflecting portion for effecting diffuse reflection of light guided into the light-guiding plate from the side peripheral surface is provided in a first region surrounding a position corresponding to the through hole, on the rear surface of the light-guiding plate, and a total internal reflection portion for effecting total internal reflection of light guided into the light-guiding plate from the side peripheral surface is provided in a second region further to the outside of the first region.

Description

Light irradiation device

The present invention relates to a light irradiation device.

As a light irradiation device used in an inspection device for inspecting a defect of a workpiece, for example, Patent Document 1 has a plate shape having a light source, a front surface, a back surface, and a side peripheral surface, and the surface is a workpiece to be inspected. And a light guide plate into which the light of the light source is introduced from the side peripheral surface, and light introduced from the side peripheral surface of the light guide plate by a diffuse reflection portion provided on the back surface of the light guide plate Is configured to diffusely reflect and emit from the surface.

The conventional light irradiation apparatus includes a cover body arranged to cover the back surface of the light guide plate, and has a structure in which the workpiece is observed through a through hole provided in the center of the cover body. .

However, in the conventional light irradiation device in which the diffuse reflection portion is formed up to the peripheral portion of the light guide plate, a part of the light introduced from the side peripheral surface of the light guide plate toward the back side of the light guide plate is a light source of the diffuse reflection portion. Because the light is diffusely reflected in the vicinity, light emitted from the vicinity of the light source of the light guide plate, that is, from the end side far from the through hole of the light guide plate is extremely strong, and light emitted from the center side of the light guide plate is weak. . As a result, light could not be efficiently irradiated to the workpiece. Further, when viewed as the entire light guide plate, there is also a problem that light unevenness is large between the end portion side and the center side.

JP 2016-136124 A

SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to provide a light irradiation device that can efficiently irradiate a work with light and has small light unevenness when viewed as an entire light guide plate. It is.

That is, the light irradiation apparatus according to the present invention has a plate shape having a light source, a front surface, a back surface, and a side peripheral surface, and the surface is disposed toward the workpiece, and light from the light source is emitted from the side peripheral surface. A light irradiating device configured to reflect the light introduced into the light guide plate from the side peripheral surface thereof and to be emitted from the surface. The cover further includes a cover body provided with a through hole at a predetermined location, and a first region around a portion corresponding to the through hole is provided on the back surface of the light guide plate. A diffuse reflection part that diffuses and reflects light introduced into the light guide plate from the side peripheral surface is provided, and the second region further outside the first region is introduced into the light guide plate from the side peripheral surface. A total reflection part that totally reflects the emitted light is provided. And it is characterized in and.

If it is such, since a total reflection part is provided in the outer side of the diffuse reflection part in the back surface of a light-guide plate, it goes to the back surface side of a light-guide plate among the light of the light source introduced from the side peripheral surface of a light-guide plate. Part of the light is reflected by the total reflection portion and guided to the center side of the light guide plate. Thereby, the light guide | induced to the center side of a light-guide plate increases, and the light inject | emitted from the center side of a light-guide plate becomes strong. As a result, the workpiece can be efficiently irradiated with light. In addition, the light emitted from the center side of the light guide plate becomes stronger, while the light emitted from the vicinity of the light source (outside) of the light guide plate becomes weaker. The non-uniformity becomes smaller.

Further, the size of the hole in the cut surface obtained by cutting the through hole in parallel with the back surface of the light guide plate may be reduced toward the light guide plate. If it is such, the installation area | region with respect to the workpiece | work of the camera arrange | positioned at the back surface side of a light-guide plate will spread, Thereby, when arrange | positioning a workpiece | work and a camera with respect to a light irradiation apparatus, the freedom degree in the arrangement | positioning has it. In addition, installation of each device becomes easier.

Also, as a camera for observing the workpiece, a line-shaped camera may be used in order to efficiently observe the entire workpiece. In this case, it is preferable that the through hole has a slit shape.

Further, the diffuse reflection portion may be a laminate in which a diffuse reflection layer is laminated on the entire surface of the first region. If it is such, since a diffused reflection layer can be formed by printing, for example, the number of parts which comprise a light irradiation apparatus can be reduced, and productivity improves. Moreover, even if the diffuse reflection part has a complicated shape, it can be easily formed.

Also, for example, when the diffuse reflection layer is thin, a part of the light incident on the diffuse reflection part is transmitted, and the light transmitted through the diffuse reflection part is absorbed by the cover body, resulting in light loss. Therefore, a reflection member that reflects the light transmitted through the diffuse reflection portion toward the light guide plate may be further provided between the diffuse reflection portion of the light guide plate and the cover body. If it is such, since the light which permeate | transmitted the diffuse reflection part is reflected by a reflection member and returned to a light-guide plate, the loss of light can be reduced. As a result, the workpiece can be irradiated with light more efficiently.

According to the light irradiation apparatus having such a configuration, it is possible to efficiently irradiate the work with light and to improve the uniformity of light emitted from the light guide plate.

It is sectional drawing which shows typically the inspection apparatus which concerns on this embodiment. It is a schematic diagram which shows the positional relationship of the light-guide plate and light source of the light irradiation apparatus which concerns on the same embodiment. It is the typical perspective view which looked at the light irradiation apparatus which concerns on the same embodiment from the surface side of the light-guide plate. It is the typical perspective view which looked at the light irradiation apparatus which concerns on the same embodiment from the back surface side of the light-guide plate. It is sectional drawing which shows typically the structure of the light source vicinity of the light irradiation apparatus which concerns on other embodiment. It is a schematic diagram which shows the relationship between the through-hole and 1st area | region which concern on other embodiment.

DESCRIPTION OF SYMBOLS 100 Light irradiation apparatus 10 Light source 20 Light guide plate 21 Front surface 22 of a light guide plate Back surface 23 of a light guide plate Side peripheral surface 24 of a light guide plate Diffuse reflection part 25 Total reflection part 30 Case 40 Reflective member

Hereinafter, a light irradiation apparatus according to the present invention and an inspection apparatus including the light irradiation apparatus will be described with reference to the drawings.

The inspection apparatus A according to the present invention is used to inspect defects (scratches, dirt, foreign matter, etc.) of the workpiece W, and is installed in a conveyance line that conveys the workpiece W in, for example, a factory. It is what is done.

<Embodiment>
As shown in FIG. 1, the inspection apparatus A according to the present embodiment is arranged on the opposite side of the light irradiation apparatus 100 that irradiates light to the work W to be inspected and the light irradiation apparatus 100 with respect to the work W. And a camera C. As the camera C, for example, a CCD camera can be used. The camera of this embodiment is a line camera.

As shown in FIGS. 1 to 4, the light irradiation device 100 has a plate shape having a light source 10, a front surface 21, a back surface 22, and a side peripheral surface 23, and the front surface 21 is disposed toward the workpiece W. The light guide plate 20 into which the light of the light source 10 is introduced from the side peripheral surface 23, the housing 30 that supports the light guide plate 20 and the light source 10 and covers the back surface 22 of the light guide plate 20, and the back surface 22 of the light guide plate 20 and the housing And a reflection member 40 disposed between the body 30 and the body 30. The housing 30 is provided with a through hole 30 a for observing the workpiece W by the camera C at a predetermined location covering the back surface 22 of the light guide plate 20. The through hole 30a of the present embodiment has a slit shape extending along the longitudinal direction of the line camera (see FIG. 4).

The light source 10 includes a plurality of LEDs arranged at equal intervals along the side peripheral surface 23 of the light guide plate 20, and the light emission direction thereof faces the side peripheral surface 23. The light source 10 further includes a lens extending along the side peripheral surface 23 in the light emission direction. In the present embodiment, the light source 10 is disposed to face the side circumferential surface 23 along the longitudinal direction of the light guide plate 20 with respect to the light guide plate 20, and the side circumferential surface 23 along the width direction of the light guide plate 20. Is not arranged.

The light guide plate 20 is a transparent plate having a rectangular shape in plan view, and is composed of, for example, an acrylic plate or a glass plate, and the surface 21 is provided with a non-reflective coating. The light guide plate 20 is arranged such that its longitudinal direction is parallel to the longitudinal direction of the slit-shaped through hole 30a. As shown in FIG. 2, on the back surface 22 of the light guide plate 20, the first region 22 a, which is a region on both sides of the portion corresponding to the through hole 30 a, is introduced into the light guide plate 20 from the side peripheral surface 23. A diffuse reflector 24 that diffusely reflects the reflected light is provided along the longitudinal direction of the through hole 30a. Further, on the back surface 22 of the light guide plate 20, the second region 22b, which is a region closer to the end than the first region 22a, is totally reflected by the light introduced into the light guide plate 20 from the side peripheral surface 23. The reflection part 25 is provided along the longitudinal direction of the through hole 30a. That is, the second region 22 b is a region between the first region 22 a and the side peripheral surface 23 on the back surface 22 of the light guide plate 20, in other words, a peripheral region on the back surface 22 of the light guide plate 20.

The diffuse reflection portion 24 is obtained by laminating a diffuse reflection layer 24a on the first region 22a. The diffuse reflection portions 24 are preferably provided 10 to 20 mm apart from the light source 10 in the width direction of the light guide plate 20, and are formed as a pair with an interval of 2 to 20 mm so as to sandwich the through hole 30 a. In addition, the diffuse reflection layer 24a of the present embodiment is formed by printing ink on the entire surface of the first region 22a without any gap. As the ink, white ink is used and formed with a thickness of 20 to 25 μm. In addition to this, not only ink but also paint may be applied on the light guide plate 20 and laminated.

The housing 30 is formed in a rectangular shape in plan view, and supports the light guide plate 20 and the light source 10. Specifically, the housing 30 includes a cover body 31 disposed so as to cover the back surface 22 of the light guide plate 20, a frame-shaped side plate 32 disposed so as to surround the side peripheral surface 23 of the light guide plate 20, It has.

The cover body 31 includes the through-hole 30a, and the through-hole 30a is formed at the center of the cover body 31 in the width direction along the longitudinal direction of the cover body 31. Further, the through hole 30 a has a substantially V-shaped cross section, and specifically, the size of the hole in the cut surface when cut in parallel with the back surface 22 of the light guide plate 20 faces the back surface 22 of the light guide plate 20. The shape gradually becomes smaller. Further, the cover body 31 is provided with a connection piece 31 a for connecting to the side plate 32 at the side edge portion. The cover body 31 has the same thickness at the portion facing the back surface 22 of the light guide plate 20 except for the connection piece 31a.

The side plate 32 supports the light source 10 in a recess 32 a provided on an inner surface facing the side peripheral surface 23 of the light guide plate 20. Moreover, the cover part 32b which covers the surface 21 of the light-guide plate 20 is extended inward from the inner surface from the side plate 32. As shown in FIG. Further, the side plate 32 is provided with a mounting groove 32c used on the outer surface of the side plate 32 when the light irradiation device 100 is installed.

The housing 30 supports the light guide plate 20 fitted in the frame of the side plate 32 with the cover portion 32b of the side plate 32 and the cover body 31 interposed therebetween. In this state, the cover portion 32 b of the side plate 32 is disposed so as to cover the surface of the surface 21 of the light guide plate 20 opposite to the total reflection portion 25. In addition, it is preferable that the housing | casing 30 is formed with the material which has light-shielding property and has heat dissipation, for example. Specifically, it is preferably formed of a metal such as an aluminum alloy.

The reflection member 40 is a thin plate attached to the inner surface of the cover body 31. In the present embodiment, the light guide plate 20 is disposed between the diffuse reflection part 24 provided on the back surface 22 of the light guide plate 20 and the cover body 31, but may be opposed to a part or all of the total reflection part 25. Moreover, the reflecting member 40 is composed of, for example, a reflecting mirror, and is arranged with its reflecting surface directed toward the diffuse reflecting portion 24 side. The reflection member 40 plays a role of reflecting light transmitted through the diffuse reflection part 24 among the light introduced into the light guide plate 20 toward the light guide plate 20.

In the present embodiment, the diffuse reflection portion 24 and the reflection member 40 are sandwiched between the light guide plate 20 and the cover body 31, and the total reflection portion 25 and the cover body 31 on the back surface 22 of the light guide plate 20 are arranged. An air layer AL is formed between the two.

According to the inspection apparatus A according to the present embodiment configured as described above, first, the light irradiation device 100 is installed so that the surface 21 of the light guide plate 20 faces the workpiece W side, and the back surface 22 side of the light guide plate 20 is provided. Camera C is installed in In addition, since the through-hole 30a of the light irradiation apparatus 100 has a substantially V-shaped cross section, as shown in FIG.

Then, light is irradiated to the workpiece W from the light irradiation device 100. At this time, the light emitted from the light source 10 enters the light guide plate 20 from the side peripheral surface 23 of the light guide plate 20, and a part of the light traveling toward the back surface 22 side of the light guide plate 20 is reflected by the total reflection unit 25. The light is totally reflected and guided to the center side of the light guide plate 20. Then, after being totally reflected by the inner surface of the surface 21 of the light guide plate 20 and diffusely reflected by the diffuse reflection portion 24 (diffuse reflection layer 24a), the light is emitted from the light guide plate 20 to the outside and irradiated onto the workpiece W. Some of the light traveling toward the rear surface 22 side of the light guide plate 20 is directly incident on the diffuse reflection portion 24 and is diffusely reflected. Such light is also emitted from the light guide plate 20 to the outside and irradiated onto the workpiece W. Is done. Of the light incident on the diffuse reflector 24, the light transmitted through the diffuse reflector 24 is also reflected by the reflecting member 40 toward the light guide plate 20 and is irradiated onto the workpiece W.

Then, the workpiece W irradiated with light in this way is imaged by the camera C through the through hole 30a, and the workpiece W is inspected based on the image obtained by the imaging.

Thus, according to the inspection apparatus A of the present embodiment, since the total reflection portion 25 is provided outside the diffuse reflection portion 24 on the back surface 22 of the light guide plate 20, it is introduced from the side peripheral surface 23 of the light guide plate 20. Of the light from the light source, a part of the light traveling toward the back surface 22 of the light guide plate 20 is reflected by the total reflection portion 25 and guided to the center side of the light guide plate 20. Therefore, although the light emitted from the vicinity of the light source 10 (end) of the light guide plate 20 is weakened, the light emitted from the inside of the light guide plate 20 is strengthened. Thereby, the work W can be efficiently irradiated with uniform light from the entire surface of the light guide plate 20.

Moreover, since the diffuse reflection part 24 is formed by printing ink, it can be easily formed. In addition, since the light transmitted through the diffuse reflection portion 24 is reflected by the reflecting member 40 toward the light guide plate 20, the light loss can be further eliminated.

Furthermore, in such a case, since the light guide plate 20 is interposed between the camera C and the work W, it is possible to prevent dust and the like from falling from the camera C side to the work W side.

<Other embodiments>
As other embodiment, the cover body 31 as shown in FIG. 5 can be mentioned. Specifically, in the cover body 31 shown in FIG. 5, the side plate 32 side is thicker than the through hole 30a side. In addition, an air layer AL is formed between the side plate 32 side formed to be thicker than the cover body 31 and the back surface 22 (specifically, the total reflection portion 25) of the light guide plate 20. In such a case, the thickness of the cover body 31 in the vicinity of the light source 10 is increased, so that the heat generated by the light source 10 is radiated more efficiently.

In the embodiment, the diffuse reflection layer 24a is laminated on the first region 22a to form the diffuse reflection portion 24. For example, the entire region of the first region 22a is damaged by, for example, blasting. The portion 24 may be formed. Furthermore, the diffuse reflection part 24 may be formed by installing a member that diffuses and reflects light separate from the light guide plate 20 in the first region 22a.

In the above-described embodiment, the through hole 30a is formed in a slit shape in accordance with the line camera. However, the present invention is not limited to this, and may be, for example, a circular shape or a rectangular shape. When the through hole 30a is circular or rectangular, the first region 22a is formed around the portion corresponding to the through hole 30a on the back surface 22 of the light guide plate 20, and the second region 22b is formed outside thereof. To do. Further, the light source 10 is disposed on the entire circumference of the side peripheral surface 23 of the light guide plate 20. Similarly, in the above-described embodiment, the light guide plate 20 is rectangular, but is not limited thereto, and may be, for example, circular.

In addition, the back surface 22 of the light guide plate 20 in the embodiment includes a region without the diffuse reflection portion 24 at a portion corresponding to the through hole 30a so that the workpiece W can be observed from the through hole 30a through the light guide plate 20. It only has to be. Therefore, for example, if the through hole 30a is circular, the first region 22a may be formed up to the inside of the portion corresponding to the through hole 30a as shown in FIG. As shown to b), you may form in the outer side of the site | part corresponding to the through-hole 30a.

In the above embodiment, the through hole 30 a is formed in the central portion of the cover body 31, but the through hole 30 a may be formed in addition to the central portion of the cover body 31.

In addition, it goes without saying that 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.

According to the light irradiation apparatus according to the present invention, it is possible to efficiently irradiate the work with light and to improve the uniformity of light emitted from the light guide plate.

Claims

A light source;
A plate having a front surface, a back surface, and a side peripheral surface, and the light guide plate into which light from the light source is introduced from the side peripheral surface while the surface is disposed toward the workpiece,
A light irradiation device configured to reflect light introduced into the light guide plate from the side peripheral surface and to be emitted from the surface,
It is arranged so as to cover the back surface of the light guide plate, and further comprises a cover body provided with a through hole at a predetermined location,
On the back surface of the light guide plate, the first region around the portion corresponding to the through hole is provided with a diffuse reflection portion that diffuses and reflects light introduced into the light guide plate from the side peripheral surface, and The light irradiation apparatus according to claim 1, wherein a total reflection portion that totally reflects light introduced into the light guide plate from the side peripheral surface is provided in the second region further outside the first region.
The light irradiation device according to claim 1, wherein the size of the hole in the cut surface obtained by cutting the through hole in parallel with the back surface of the light guide plate decreases toward the light guide plate.
The light irradiation device according to claim 1, wherein the through hole has a slit shape.
The light irradiating apparatus according to claim 1, wherein the diffuse reflection portion is formed by laminating a diffuse reflection layer over the entire first region.
The light irradiation apparatus according to claim 1, further comprising a reflection member that reflects light transmitted through the diffuse reflection portion toward the light guide plate between the diffuse reflection portion of the light guide plate and the cover body.