JP2011089869A - Lighting system for image processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain bright diffusion light having uniform brightness by an inexpensive device in a compact configuration. <P>SOLUTION: A light source 3 is allowed to oppose a front 4 of one or two diffusion plates 2; irradiation light from the light source 3 is made incident to the inside of the diffusion plate 2 from the front 4 of the diffusion plate 2; the incident irradiation light is diffused within the diffusion plate 2 as diffusion light; and the diffusion light is applied to an irradiation target from an end face 6 for irradiation in the diffusion plate. A reflecting plate 9 also used for shielding light is integrally installed at the side of the light source 3 in the diffusion plate 2, and irradiation light from the light source 3 is reflected by the reflecting plate 9 to enter the diffusion plate 2. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to an apparatus used to illuminate a workpiece when the workpiece is photographed and image data is processed.

When inspecting a work piece such as a glossy metal surface, a polycrystalline silicon wafer, or a foreign object or dirt on the surface, an illumination device suitable for the work is required. In order to make it easy to detect cracks on the workpiece, foreign matter and dirt on the surface, a technique is used that suppresses reflection from the workpiece as much as possible using indirect light or diffused light.

As a method of creating indirect light or diffused light, a flat diffuser plate is used in addition to the dome-shaped illumination disclosed in Patent Document 1, but the dome-shaped illumination tends to be large and flat. However, this type of diffusion plate has the disadvantage that the thickness and size of the diffusion plate must be increased in order to produce a sufficient diffusion effect.

On the other hand, Patent Document 2 generates linear (line-shaped) illumination light by combining a diffusion plate and an optical fiber. However, such an illumination device has a complicated configuration, is expensive, and cannot be widely used for simple devices.

JP 08-334469 A JP 06-267315 A

Therefore, a problem to be solved by the present invention is to make it possible to obtain diffused light with a compact structure and bright and uniform brightness by an inexpensive device.

Under the above-mentioned problems, the present invention makes the light source face the front surface of the diffusion plate, makes the irradiation light from the light source incident on the inside of the diffusion plate from the front surface of the diffusion plate, and the irradiation light incident inside the diffusion plate. The diffused light is diffused to be diffused light, and this diffused light is irradiated to the illumination target from the irradiation end face of the diffusion plate.

Further, in the present invention, two diffusion plates are arranged in parallel with a visual field space, a light source is opposed to the front surface of each diffusion plate, and the diffused light is irradiated to the illumination target from the irradiation end surface of each diffusion plate. (Claim 2).

Further, according to the present invention, a light-reflecting reflecting plate is installed on the light source side of the diffusing plate so as to be in contact with the lower end edge on the front surface of the diffusing plate, and the irradiation light from the light source is reflected by the reflecting plate. It is made to enter inside (Claim 3).

In the present invention, the light source is a linear light source parallel to the end face of the diffusion plate, and the irradiation light is uniformly distributed over the longitudinal direction of the end face for irradiation.

Further, according to the present invention, the light diffusion particles are dispersed inside the diffusion plate (Claim 5), or the light diffusion film, the light reflection film, and the light diffusion reflection film are formed on the back surface of the diffusion plate and the end surface other than the irradiation end surface. Any one is formed, the light diffusion effect is enhanced by the light diffusion function, and the light transmission of the diffusion plate is suppressed by the reflection function, so that the irradiation light from the light source can be used effectively (Claim 6). .

According to the present invention, the irradiation light from the light source enters from the front surface of the wide area of the diffusion plate, diffuses in the diffused light to become diffused light, and forms a linear or belt-like shape from the irradiation end surface of the diffusion plate to the work surface. Irradiated. For this reason, the irradiation light on the optical axis of the light source and the central illumination light from the irradiation end face are in a right angle direction or a direction close to a right angle, and a sufficient diffusion effect can be expected by a long diffusion light path inside the diffusion plate. The light beam is not biased, and uniform illumination light can be obtained in the longitudinal direction of the line or band. Furthermore, it is possible to provide a compact and inexpensive apparatus as compared with the dome type illumination. In particular, this illumination is effective for a line type CCD having a linear or belt-like irradiation area parallel to the X axis or Y axis as an imaging area.

In addition, if there are two light sources, the amount of light increases accordingly, and brighter and more uniform illumination can be obtained. In addition, a camera such as a line-type CCD is perpendicular to the surface of the workpiece with a viewing space between the two diffusers. Therefore, it becomes possible to photograph the work in the photographing area with little distortion.

In addition, if a reflector is provided, the light reflected by the reflector can also be used, so that the light emitted from the light source can be used effectively. Thus, there is no external incident light in the imaging area, and clear imaging is possible.

Since the light source is a linear light source parallel to the end face of the diffuser plate, illumination light with a uniform distribution can be obtained over the longitudinal direction of the end face for irradiation.

Furthermore, the diffusion and reflection of light can be appropriately controlled according to the application by dispersing the light diffusing particles (Claim 5) and forming the light diffusing film and the light reflecting film (Claim 6).

It is a side view of the illuminating device for image processing of this invention. It is a side view of the other illumination device for image processing of this invention. It is a side view of the lighting apparatus for further image processing of this invention.

FIG. 1 shows a basic image processing illumination apparatus 1 according to the present invention. The image processing illumination device 1 includes a rectangular flat diffusion plate 2 and a light source 3. The diffusion plate 2 is made of a plastic plate, particularly an acrylic resin plate. The light source 3 is configured as a linear light source by linearly arranging one or a plurality of line light sources such as a rod-shaped fluorescent lamp, or a plurality of point light sources such as LEDs and incandescent lamps.

The diffusion plate 2 is opposed to the light source 3 on the flat front surface 4. Of the four sides of the diffusion plate 2, the side facing the workpiece 10 to be illuminated, for example, the irradiation end surface 6 on the lower side, An appropriate distance is set with respect to the workpiece 10 and faces the workpiece surface in parallel. As a result, the diffusing plate 2 and the workpiece surface of the workpiece 10 face each other at a right angle when viewed from the side, but this angle can also be an angle close to a right angle.

The light source 3 has its optical axis orthogonal to the center position of the front surface 4 of the diffusion plate 2, parallel to the upper and lower sides of the diffusion plate 2, and parallel to the irradiation area of the workpiece 10. Is set.

When illuminating the workpiece 10, the light emitted from the light source 3 enters the diffuser 2 from the front surface 4 of the diffuser 2, diffuses inside the diffuser 2, and becomes uniform diffused light. The diffused light exits from the irradiation end face 6 of the diffusing plate 2 and is irradiated on the irradiation area of the work 10 as a line or a band. Under this illumination, the camera 8, for example, a line CCD, is installed near the back surface 5 of the diffusion plate 2, images a linear or belt-shaped irradiation area of the work 10, and the image processing apparatus 11 takes an image. Send a signal. Here, the image processing apparatus 11 performs image processing on the image signal, and detects cracks in the workpiece 10, surface defects, dirt, and the like.

According to the example of FIG. 1, the irradiation light from the light source 3 enters from the front surface 4 of the wide area of the diffusion plate 2 and diffuses into the diffused light to become diffused light. 10 surfaces are irradiated as lines or bands. In this way, since the area is reduced, very bright illumination can be obtained as compared with the dome illumination, and the illumination light on the optical axis of the light source 3 and the illumination light at the center from the illumination end face 6 are reduced. Since a sufficient diffusion effect can be expected by a long diffusion light path in the diffusion plate 2 in a right angle direction or a direction close to a right angle, there is no deviation of light flux, and uniform illumination light can be obtained in a linear or belt-like longitudinal direction. . Furthermore, it is possible to provide a compact and inexpensive apparatus as compared with the dome type illumination. This illumination is effective for the camera 8 having a linear or belt-shaped irradiation area parallel to the X axis or Y axis as an imaging area, particularly for a line CCD.

Next, FIG. 2 shows an example in which the image processing illumination apparatus 1 is configured by arranging two diffusion plates 2 in parallel. The two diffusion plates 2 are arranged in parallel in the visual field space of the camera 8 such as a line CCD, and the linear light source 3 faces the front surface 4 of the corresponding diffusion plate 2.

Irradiation light from each light source 3 enters from the front surface 4 of each diffusing plate 2, diffuses inside the diffusing plate 2, and becomes diffused light from the irradiation end surface 6 of each diffusing plate 2 to the workpiece 10. Irradiated as a band.

According to the example of FIG. 2, the amount of light increases in a superimposed manner, brighter and more uniform illumination can be obtained, and the camera 8 such as a line CCD is placed on the surface of the work 10 with the space between the two diffusion plates 2 as a visual field space. Since they face each other from the right angle direction, the work 10 in the photographing area can be photographed with little distortion.

Further, in FIG. 3, the image processing illumination device 1 is configured by disposing a reflection plate 9 that also serves as a light shield at each hem portion of the two diffusion plates 2 at an angle of, for example, about 45 degrees with respect to the diffusion plate 2. An example is shown. The light-shielding reflection plate 9 is integrally attached to the lower side of the light source side of each diffusion plate 2 as being attached to each diffusion plate 2. The light-shielding reflector 9 can be integrally attached to the single diffusion plate 2 shown in FIG.

Irradiation light from each light source 3 is directly incident on the inside of the corresponding diffusion plate 2 from the front surface 4 or is reflected by the reflection plate 9 and then indirectly incident and diffused inside each diffusion plate 2. Become light. In the example of FIG. 3, the same function as in the example of FIG. 2 can be obtained. In particular, since the light reflected by the reflecting plate 9 can also be used, the irradiation light of the light source 3 can be used effectively. Since the part 10 of the light source 3 is not directly applied to the work 10 by the light shielding function, there is no external incident light in the imaging area, and clear imaging is possible.

The light diffusing effect of the diffusing plate 2 is such that light diffusing particles such as aluminum or bubbles are dispersed inside the diffusing plate 2, or a light diffusing film, a light reflecting film or a light diffusing reflecting film on the back surface 5 of the diffusing plate 2. Can be enhanced by forming. If a light reflection film is formed on the back surface 5 of the diffusion plate 2 or the three end surfaces 7 other than the irradiation end surface 6, transmission of diffused light inside the diffusion plate 2, that is, dissipation to the outside can be suppressed. Effective use of light is further possible.

The illumination device 1 for image processing according to the present invention was developed for image processing for detecting cracks, surface defects, and dirt of the workpiece 10, but is not limited to the above detection, and is used in fields such as morphological observation and measurement. Can also be widely applied.

DESCRIPTION OF SYMBOLS 1 Image processing illuminating device 2 Diffusion plate 3 Light source 4 Front surface 5 Back surface 6 End surface 7 for irradiation 7 End surface 8 Camera 9 Reflector 10 Workpiece 11 Image processing device

Claims (6)

The light source is opposed to the front surface of the diffuser plate, the light emitted from the light source is incident on the diffuser plate from the front surface of the diffuser plate, and the light incident on the diffuser plate is diffused to form diffuse light. Is irradiated to the object to be illuminated from the irradiation end face of the diffusion plate. Two diffusion plates are arranged in parallel with a visual field space, a light source is opposed to the front surface of each diffusion plate, and diffused light is irradiated to an illumination target from an irradiation end surface of each diffusion plate. Item 2. The illumination device for image processing according to Item 1. Install a light-shielding reflector on the light source side of the diffuser so that it is in contact with the lower edge at the front of the diffuser, and reflect the light from the light source on the reflector so that it enters the diffuser. The illumination device for image processing according to claim 1 or 2. 4. The illumination device for image processing according to claim 1, wherein the light source is a linear light source parallel to the irradiation end face of the diffusion plate. 5. The image processing illumination device according to claim 1, wherein the light diffusion particles are dispersed inside the diffusion plate. The light diffusion film, the light reflection film, or the light diffusion reflection film is formed on the back surface of the diffusion plate and the end surface other than the irradiation end surface. The illumination device for image processing according to claim 4 or 5.

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