WO2023204320A1

WO2023204320A1 - Image acquisition system for detecting carbide insert locations and image acquisition method thereof

Info

Publication number: WO2023204320A1
Application number: PCT/KR2022/005575
Authority: WO
Inventors: 송일재
Original assignee: 주식회사 윈텍오토메이션
Priority date: 2022-04-18
Filing date: 2022-04-19
Publication date: 2023-10-26
Also published as: KR20230148627A

Abstract

The present invention relates to an image acquisition system for detecting carbide insert locations and an image acquisition method using the image acquisition system, and to an image acquisition system for detecting the locations of sintered carbide inserts scattered on a sintered plate, the image acquisition system comprising: an image acquisition unit that comprises a lens and a camera, for photographing the locations of sintered carbide inserts, and a lighting device electrically connected to the camera and vertically irradiating the sintered plate; a sintered plate transfer unit that is located under the image acquisition unit and transfers the sintered plate so that the location of each sintered carbide insert can be photographed; and a frame which is installed over and across the sintered plate transfer unit (200) at a right angle and on which the image acquisition unit is loaded. Therefore, by using the image acquisition system including the camera, the lens, and the lighting device, entire images of the sintered carbide inserts scattered on the sintered plate are acquired, to accurately detect the location of each sintered carbide insert, and thus, a process for extracting the sintered carbide inserts can be performed smoothly.

Description

Image acquisition system and image acquisition method for detecting carbide insert position

The present invention relates to an image acquisition system and an image acquisition method for detecting the position of a carbide insert, and more specifically, to detecting each position using images obtained by photographing sintered carbide inserts scattered on a sintered plate. It's about technology.

In general, a cutting tool is mainly used for cutting ferrous, non-ferrous metals, and non-metallic materials, and is a tool that is usually mounted on a machine tool and performs cutting to process a workpiece into a desired shape.

Carbide inserts used in cutting tools are made by bonding diamond powder or cemented carbide powder to iron (Fe), tungsten (W), cobalt (Co), copper (Cu), nickel (Ni), tin (Sn), and copper. -It is a sintered alloy mixed with metal powders such as tin (CuSn), zinc (Zn), copper-zinc (CuZn), and silver (Ag).

Carbide inserts are completed through molding, sintering, polishing, coating, and finally an inspection process. The ‘sintered carbide insert’ used in the present invention refers to a sintered body that has completed the sintering process and is scattered on the sintered plate and waiting to be input into future polishing, coating and inspection processes.

The sintered carbide insert requires accurate gripping technology from a gripper in order to be loaded on a pallet and transported to the next process, and for accurate gripping, each sintered body on the sintered plate must be photographed and its position acquired.

The present invention uses an image acquisition system with improved cameras, lenses, and lighting devices to capture images of the upper surface of sintered carbide inserts to obtain accurate location information of each sintered body, thereby improving the gripping accuracy of the gripper to ensure the safety of the main equipment. We aim to provide an image acquisition system for detecting the position of a carbide insert that is configured to respond to the next process and an image acquisition method using the system.

The purpose of the present invention to solve the above-mentioned problems is to attach a sintered carbide insert to a sintered carbide insert extraction device (hereinafter referred to as 'main equipment') to accurately grasp the sintered carbide insert that has completed the sintering process and load it on a pallet. The purpose is to provide an image acquisition system for detecting the insert position.

Another object of the present invention is to provide an image acquisition system for detecting the position of a carbide insert, which includes an image acquisition unit, a sintered plate transfer unit, and a frame.

Another object of the present invention is that the image acquisition unit consists of a lens/camera that photographs the position of each of the sintered carbide inserts, and a lighting device that is electrically connected to the camera and irradiates the sintered plate vertically. The purpose is to provide an image acquisition system for detecting the position of a carbide insert.

Another object of the present invention is that the lighting device is an LED lighting configured to form a plurality of LED modules in a straight line and couple them to the lower side of each side of a square frame to irradiate downward, and each LED module has a convex light. The aim is to provide an image acquisition system for detecting the position of a carbide insert, which is configured to form a lens so that the transmitted light rays are collected at the image acquisition point.

Another object of the present invention is to detect the position of the sintered carbide insert, wherein the sintered plate transfer unit is located below the image acquisition unit and is configured to transfer the sintered plate so that each position of the sintered carbide insert can be photographed. The goal is to provide an image acquisition system.

Another object of the present invention is to provide an image acquisition system for detecting the position of a carbide insert, wherein the frame is installed across the upper part of the sintered plate transfer unit at a right angle and the image acquisition unit is mounted. .

The purpose of the present invention to solve the above-described problems is to provide an image acquisition method for detecting the position of a carbide insert comprising the following steps: (a) preparation step, (b) shooting and image acquisition step, and (c) position detection step. There is something to do.

Another object of the present invention is that the preparation step (a) consists of moving the prepared camera to the image acquisition point to focus the lens in order to photograph the positions of each of the sintered carbide inserts scattered on the sintered plate. The purpose is to provide an image acquisition method for detecting the position of a carbide insert.

Another object of the present invention is to provide an image acquisition method for detecting the position of a carbide insert in which the (a) preparation step is configured to irradiate the sintered plate with the LED light of the lighting device.

Another object of the present invention is to provide an image acquisition method for detecting the position of a carbide insert in the (b) image capturing and acquisition step, which is configured to photograph the upper surface of the sintered carbide insert while moving the image acquisition point of the sintered plate. It is to provide.

Another object of the present invention is that the image acquisition point in the (b) shooting and image acquisition step is a camera that shoots vertically from the top, and an image for detecting the position of the carbide insert that is sequentially taken at the orthogonal point where the sintered plate is transported. The purpose is to provide a method.

Another object of the present invention is that the (c) position detection step is for detecting the position of the carbide insert, which is configured to detect the position of each sintered carbide insert on the sintered plate based on the image acquired in step (b). The goal is to provide an image acquisition method.

The feature of the image acquisition system for detecting the position of the carbide insert of the present invention to achieve this purpose is that it is configured to accurately grasp the sintered carbide insert that has completed the sintering process by combining it with the ‘main equipment’ and load it on the pallet.

Another feature of the present invention includes an image acquisition unit, a sintered plate transfer unit, and a frame.

Another feature of the present invention is that the image acquisition unit consists of a lens/camera that photographs the position of each of the sintered carbide inserts, and a lighting device that is electrically connected to the camera and irradiates the sintered plate vertically. do.

Another feature of the present invention is that the lighting device is an LED lighting configured to form a plurality of LED modules in a straight line and couple them to the lower side of each side of a square frame to irradiate downward, and each LED module has a convex light. It is configured to form a lens so that the transmitted light rays are collected at the image acquisition point.

Another feature of the present invention is that the sintered plate transfer unit is located below the image acquisition unit and is configured to transfer the sintered plate so that the positions of each of the sintered carbide inserts can be photographed.

Another feature of the present invention is that the frame is installed across the upper part of the sintered plate transfer unit at a right angle so that the image acquisition unit is mounted.

The characteristics of the image acquisition method for detecting the position of the carbide insert of the present invention to achieve this purpose include (a) a preparation step, (b) a photographing and image acquisition step, and (c) a position detection step.

Another feature of the present invention is that the preparation step (a) is configured to move the prepared camera to the image acquisition point to focus the lens in order to photograph the positions of each of the sintered carbide inserts scattered on the sintered plate. do.

Another feature of the present invention is that the preparation step (a) is configured to irradiate the sintered plate with LED lighting from a lighting device.

Another feature of the present invention is that the image capturing and acquisition step (b) is configured to photograph the upper surface of the sintered carbide insert while moving the image acquisition point of the sintered plate.

Another feature of the present invention is that the image acquisition point in the (b) photographing and image acquisition step is sequentially photographed by a camera that photographs vertically from the top and an orthogonal point where the sintered plate is transported.

Another feature of the present invention is that the position detection step (c) is configured to detect the position of each sintered carbide insert on the sintered plate based on the image acquired in step (b).

The image acquisition system of the present invention as described above is configured to acquire an image of the sintered body using a lighting device equipped with an LED module focused on the slope. Therefore, high-resolution images can be obtained by increasing the concentration efficiency of the light irradiated to the sintered body.

In addition, the lighting device of the image acquisition system of the present invention is configured by applying a condenser lens. Therefore, there is an advantage in that the efficiency of detecting the position of the sintered body can be improved by showing a light-concentrating efficiency that is more than three times that of the case where the condenser lens is not applied.

In addition, the image acquisition system of the present invention is configured so that the illumination incident angle (α) of the lighting device is 10°. Therefore, there is an advantage in that reflected light can be suppressed regardless of the type and condition of the sintered plate, allowing high-resolution images to be obtained.

Figure 1 is a diagram schematically showing a conventional image acquisition device and a photograph showing an image of a carbide insert.

Figure 2 is a configuration diagram schematically showing the main equipment (sintered carbide insert extraction device) combined with an image acquisition system for detecting the position of the carbide insert according to the present invention.

Figure 3 is a configuration diagram schematically showing an image acquisition system for detecting the position of a carbide insert according to the present invention.

Figure 4 is a configuration diagram schematically showing the image acquisition unit of the image acquisition system of the present invention.

Figure 5 is a configuration diagram schematically showing the sintered plate transfer unit of the image acquisition system of the present invention.

Figure 6 is a configuration diagram schematically showing a frame in which the image acquisition unit of the image acquisition system of the present invention is combined.

Figure 7 is a diagram schematically showing the image acquisition unit of the image acquisition system of the present invention and a diagram showing the sequence of acquiring a segmented image.

Figure 8 is a diagram showing the density of the image when the condenser lens of the lighting device according to the present invention is not applied (a) and when applied (b).

Figures 9 to 12 are video pictures of the position of the sintered body detected by the image acquisition system of the present invention.

Since the present invention can be modified in various ways and can have several embodiments, specific embodiments will be illustrated in the drawings and described in detail in the description of the invention.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms and words used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. In order to best explain one's invention, the concept of the term can be appropriately defined and must be interpreted with a meaning and concept consistent with the technical idea of the present invention.

In general, carbide inserts are completed through molding, sintering, polishing, coating, and finally an inspection process. The ‘sintered carbide insert’ used in the present invention refers to a sintered body that has completed the sintering process and is scattered on the sintered plate and waiting to be input into future polishing, coating and inspection processes.

The sintered carbide insert requires accurate gripping technology of the gripper in order to be loaded on a pallet and transported to the next process, and for accurate gripping, the sintered bodies scattered on the sintered plate must be photographed to obtain their respective positions. .

When explaining the conventional image acquisition device 1 with reference to FIG. 1, it is configured to irradiate a ring light 1.1 to the sintered plate 3 and acquire an image using a camera 1.2, but irradiates the sintered body ( There is a problem in that it is difficult to obtain good quality images for location detection due to the phenomenon of uneven lighting.

In addition, the reflection of light emitted depending on the various bottom shapes of the sintered plate (flat, protruding, discolored, damaged, etc.) causes a problem of location detection failure due to low contrast efficiency with the sintered body.

In order to solve the above-mentioned problems, the present invention uses an image acquisition system with improved cameras, lenses, and lighting devices to capture images of the upper surface of the sintered carbide insert and obtain accurate location information of each sintered body to improve the accuracy of the gripping operation of the gripper. We aim to improve the safety of expensive main equipment and provide an image acquisition system for detecting the position of carbide inserts that is configured to respond to the next process and an image acquisition method using the system.

Specific features and advantages of the present invention will become clearer from the following description with reference to the accompanying drawings.

Figure 1 is a diagram schematically showing a conventional image acquisition device and a photograph showing an image of a carbide insert, and Figure 2 is a diagram schematically showing the main equipment combined with an image acquisition system for detecting the position of a carbide insert according to the present invention. 3 is a configuration diagram schematically showing an image acquisition system for detecting the position of a carbide insert according to the present invention, Figure 4 is a configuration diagram schematically showing an image acquisition unit of the image acquisition system of the present invention, and Figure 5 is a configuration diagram schematically showing an image acquisition unit of the image acquisition system of the present invention. It is a configuration diagram schematically showing the sintered plate transfer unit of the image acquisition system of the present invention, Figure 6 is a configuration diagram schematically showing a frame to which the image acquisition unit of the image acquisition system of the present invention is combined, and Figure 7 is a configuration diagram schematically showing the frame in which the image acquisition unit of the image acquisition system of the present invention is combined. It is a diagram schematically showing the image acquisition unit of the image acquisition system and the sequence of acquiring segmented images. Figure 8 shows the density of the image when the condenser lens of the lighting device according to the present invention is not applied (a) and when applied (b). This is an illustration, and FIGS. 9 to 12 are video pictures of the position of the sintered body detected by the image acquisition system of the present invention.

<Example 1>: Image acquisition system according to the present invention

The present invention seeks to provide a system for acquiring images for detecting the positions of each sintered carbide insert scattered on a sintered plate.

Referring to Figure 2, the sintered carbide insert extraction device (hereinafter referred to as 'main equipment') combined with the image acquisition system for detecting the position of the carbide insert according to the present invention is a device for taking out the sintered body (sintered carbide insert) that has completed the sintering process. As a result, the sintered carbide insert (2) on the sintered plate (A) is held by the gripper (9.1), loaded on the pallet (B), and transferred to the next process.

3 to 6, the image acquisition system 10 for detecting the position of a carbide insert according to the present invention includes an image acquisition unit 100, a sintered plate transfer unit 200, and a frame 300. It is composed by:

The image acquisition unit 100 of the image acquisition system 10 for detecting the position of the carbide insert according to the present invention includes a lens 110 and a camera 120 for photographing each position of the sintered carbide insert (2), It is electrically connected to the camera 120 and consists of a lighting device 130 that irradiates the sintered plate 3 vertically.

At this time, the subject distance (WD: Working Distance) is 700mm, which can suppress the reflected light of the sintered plate, and the maximum outer radius is 150mm. An appropriate camera and lens are applied, and the sintered plate is divided into multiple parts (divided into 12 parts) and photographed. . (see Figure 7)

The lighting device 130 of the image acquisition unit 100 according to the present invention forms a plurality of LED modules in a straight line and is coupled to the lower side of each side of the square frame 310 to irradiate downward. It is comprised of an LED light 131 and a condenser lens 132 configured to form a convex lens on each LED module so that the transmitted light converges at the image acquisition point.

At this time, the lighting device 130 sets the illumination incident angle (α) of the LED lighting 131 to preferably 9 to 11°, and most preferably 10°. In addition, by applying a condensing lens (convex lens), the efficiency of detecting the position of the sintered body is improved by showing a light concentrating effect that is three times more than when not applied. (see Figure 8)

The sintered plate transfer unit 200 of the image acquisition system 10 for detecting the position of the carbide insert according to the present invention is located at the lower part of the image acquisition unit 100, and determines each position of the sintered carbide insert (2). It is configured to transport the sintered plate 3 so that it can be photographed.

The sintered plate transfer unit 200 of the present invention is a feeder 220 located below the image acquisition unit 100 and configured to transfer the sintered plate 3. ), a conveyor belt 230 that is coupled to the upper part of the feeder and transports the sintered plate placed on top, a grip 240 that grips both sides of the sintered plate, and an image acquisition position and gripper by moving the feeder (9.1) It is configured to include a transfer frame 210 that transfers the sintered plate to the working position.

In addition, the sintered plate transfer unit 200 of the present invention includes a servomotor 250 to move the feeder 220 on the transfer frame 210, and a drive motor that drives the conveyor belt 230. It is configured to further include (231).

At this time, the feeder 220 is a component necessary to transport the sintered plate for image acquisition work and sintered body extraction work mounted on the top, and the conveyor belt 230 moves the sintered plate forward and backward to change the process. It is necessary when doing so, and the drive motor 231 that drives the conveyor belt 230 is configured to be located inside the feeder 220. (see Figure 5)

The frame 300 of the image acquisition system 10 for detecting the position of the carbide insert according to the present invention is installed across the upper part of the sintered plate transfer unit 200 at a right angle, so that the image acquisition unit 100 It is configured to be mounted.

The frame 300 of the present invention is a rectangular shape in which the camera 120 is mounted vertically on the inside that is open at the top and bottom, and the lighting device 130 is mounted on the bottom to irradiate downward. A frame 310 and a mobile robot 320 configured to acquire images while moving a camera 120 mounted on the square frame 310, and configured to slide and move by being coupled to the mobile robot 320. It is composed of a mover 330 and a connection plate 340, both ends of which are fastened to the square frame 310 and the mover 330, respectively, to move the camera to the image acquisition point.

In addition, the frame 300 of the present invention includes a bracket 350 for combining the camera 120 and the lens 110 and fastening it to the connection plate 340, the square frame 310 and the connection plate ( A plurality of ribs 360 combining 340) are further included.

<Example 2>: Image acquisition method using the present invention

Hereinafter, a method of acquiring an image to detect the position of the sintered body using the image acquisition system of <Example 1> will be described.

The image acquisition method for detecting the position of a carbide insert according to the present invention includes (a) a preparation step (S100), (b) a photographing and image acquisition step (S200), and (c) a position detection step (S300). .

The (a) preparation step (S100) of the image acquisition method for detecting the position of the carbide insert according to the present invention is the camera prepared to photograph the positions of each of the sintered carbide inserts scattered on the sintered plate (3). It is configured to move (120) to the image acquisition point and focus the lens.

At this time, the camera and lens are adjusted so that the subject distance (WD: Working Distance) is 700mm, which can suppress the reflected light of the sintered plate, and the maximum outer radius is 150mm, and the sintered plate is divided (divided into 12 parts) and photographed. (see Figure 7)

In the preparation step (a) (S100) of the present invention, the LED lighting 131 of the lighting device 130 is configured to irradiate the sintered plate 3.

At this time, the lighting device 130 sets the illumination incident angle (α) of the LED lighting 131 to preferably 9 to 11°, and most preferably 10°. In addition, by applying a condenser lens, the efficiency of detecting the position of the sintered body is improved by showing a condensing effect that is three times more than when not applied. (see Figure 8)

The (b) image shooting and acquisition step (S200) of the image acquisition method for detecting the position of the carbide insert according to the present invention is performed by moving the image acquisition point (Aa...Dd) of the sintering plate (3) while sintering the sintering plate (3). It is configured to photograph the upper surface of the carbide insert.

The image acquisition point (Aa...Dd) of the (b) shooting and image acquisition step (S200) of the present invention is where the camera 120 vertically shoots from the top and the sintered plate 3 are transported. Photographs are taken sequentially from points (orthogonal points).

The method of photographing and acquiring an image of the sintered body in the (b) photographing and image acquisition step (S200) of the present invention will be described as follows.

[Method of acquiring top image (400) of sintered body]

The (b) photographing and image acquisition step (S200) of the present invention divides the sintered plate (Aa, Ab, Ac, Ad, Ba, Bb, Bc, Bd, Ca, Cb, Cc, Cd, Da, A plurality of image acquisition points 410 (Db, Dc, Dd) are set, and an upper surface image of the sintered body is acquired from the plurality of image acquisition points 410.

At this time, in the image acquisition of the present invention, the camera coupled to the frame 300 moves along the vertical (y-y) axis, and the sintered plate on which the sintered body moves along the horizontal (x-x) axis meets an orthogonal point (image acquisition point). It is configured so that filming takes place in . (see Figure 7)

In the (b) photographing and image acquisition step (S200) of the present invention, when the LED light 131 of the lighting device 130 is irradiated to the sintered plate 3, the illumination incident angle α is adjusted. When set to 10°, which is the most desirable, the quality of the acquired image is improved according to the condensing effect of the condenser lens coupled to the LED light 131. (see Figure 8)

9 to 12 are images captured in the (b) photographing and image acquisition step (S200) of the present invention.

In the present invention, when the distance (WD: Working Distance) of the subject is set to 700 mm, all sintered bodies on the plate are detected regardless of the type of sintered plate (FIGS. 9 to 11), and the camera recognizes sintered bodies that are not detected. Full detection (FIG. 12) can be achieved by adjusting the value.

The (c) position detection step (S300) of the image acquisition method for detecting the position of a carbide insert according to the present invention detects the position of each sintered carbide insert on the sintered plate based on the image acquired in step (b). It is configured to do so.

The method of detecting the location using the image acquired in the (c) location detection step (S300) of the present invention and applying the detected data to the main equipment is explained as follows.

[Detection and application of position of sintered body]

In the (c) position detection step (S300) of the present invention, the captured image is sent to a computer (not shown), and the location (address) of each sintered body scattered on the sintering plate is input to the controller to produce the sintered body. Ensure accurate gripping by the gripper when loading onto a pallet.

The image acquisition system for detecting the position of the carbide insert of the present invention has the following advantages.

First, the image acquisition system of the present invention is configured to acquire an image of the sintered body using a lighting device equipped with an LED module focused on a slope.

Therefore, high-resolution images can be obtained by increasing the concentration efficiency of the light irradiated to the sintered body.

In addition, the lighting device of the image acquisition system of the present invention is configured by applying a condenser lens.

Therefore, there is an advantage in that the efficiency of detecting the position of the sintered body can be improved by showing a light-concentrating efficiency that is more than three times that of the case where the condenser lens is not applied.

In addition, the image acquisition system of the present invention is configured so that the illumination incident angle (α) of the lighting device is 10°.

Therefore, there is an advantage in that reflected light can be suppressed regardless of the type and condition of the sintered plate, allowing high-resolution images to be obtained.

Claims

It relates to an image acquisition system for detecting the positions of sintered carbide inserts scattered on a sintered plate,

The image acquisition system is,

A lens 110 and a camera 120 for photographing each position of the sintered carbide insert 2, a lighting device electrically connected to the camera 120 and vertically irradiating the sintered plate 3 ( An image acquisition unit 100 consisting of 130);

A sintered plate transfer unit 200 located below the image acquisition unit 100 and transferring the sintered plate 3 so that each position of the sintered carbide insert 2 can be photographed;

Image acquisition for detecting the position of a carbide insert, comprising a frame 300 that is installed across the upper part of the sintered plate transfer unit 200 at a right angle and configured to mount the image acquisition unit 100. system.
In claim 1,

The lighting device 130 includes an LED light 131 configured to form a plurality of LED modules in a straight line and illuminate downward from the lower side of each side of the square frame 310, and light from the LED module passes through to produce an image. An image acquisition system for detecting the position of a carbide insert, characterized in that it includes a condenser lens 132 configured to gather at the acquisition point.
In claim 2,

The lighting device 130 is an image acquisition system for detecting the position of a carbide insert, characterized in that the illumination incident angle (α) of the LED lighting 131 is 10°.
In claim 3,

The sintered plate transfer unit 200 includes a feeder 220 located below the image acquisition unit 100 and configured to transfer the sintered plate 3, and the feeder 220 coupled to the upper part of the feeder and placed on top of the sintered plate 3. A conveyor belt 230 that transports the sintered plate, a grip 240 that grips both sides of the sintered plate, and a transfer frame that moves the feeder to transfer the sintered plate to the image acquisition position and the gripper (9.1) working position. (210) An image acquisition system for detecting the position of a carbide insert.
In claim 4,

The frame 300 is a square frame 310 configured to irradiate downward by mounting the camera 120 vertically on the inside that is open upward and downward, and mounting the lighting device 130 on the lower side. and a mobile robot 320 configured to enable the camera 120 mounted on the square frame 310 to move and acquire images, and a mover 330 configured to slide and move by being coupled to the mobile robot 320. ) and a connection plate 340, both ends of which are respectively fastened to the square frame 310 and the mover 330 to move the camera to the image acquisition point. An image for detecting the position of a carbide insert. Acquisition system.
Among claims 1 to 5, it relates to a method of acquiring an image for detecting the position of a sintered carbide insert using the image acquisition system of any one of the claims,

(a) Preparation step (S100) for photographing the positions of the sintered carbide inserts scattered on the sintered plate (3);

(b) a photographing and image acquisition step (S200) of photographing the upper surface of the sintered carbide insert while moving the image acquisition point (Aa...Dd) of the sintered plate (3);

(c) a position detection step (S300) of detecting the position of the carbide insert based on the image acquired in step (b); an image acquisition method for detecting the position of a carbide insert, comprising a.
In claim 6,

The (a) preparation step (S100) is an image acquisition method for detecting the position of a carbide insert, characterized in that the LED light 131 of the lighting device 130 is configured to irradiate the sintered plate 3. .
In claim 7,

The image acquisition points (Aa...Dd) of the (b) shooting and image acquisition step (S200) are sequentially orthogonal points of the camera 120 vertically photographed from the top and the transported sintering plate 3. An image acquisition method for detecting the position of a carbide insert, characterized in that the image is acquired by shooting.
In claim 7,

An image acquisition method for detecting the position of a carbide insert, characterized in that the illumination incident angle (α) of the lighting device 130 is 10°.