JPH04297810A - Optical tester - Google Patents

Abstract

PURPOSE:To enable irradiation with beams of light over a wide range on a test object by irradiating the test object directly with beams of light diffused by a diffusion plate over a wide range and by guiding the reflected light in a direction different from that of incident light. CONSTITUTION:An emitted beam of light from a light source 2 is guided to a vicinity of a test object 10 by an optical fiber 14: after a diffusion plate 16 enlarges the irradiation range, this beam passes through a half mirror 6 to irradiate the object 10 from sideward. The mirror 6 reflects the reflected light of the object 10 in parallel with the axial line of the object 10, and a reflector 18 counterposed against the mirror 6 reflects that reflected light sideward by 90 deg.. A prism 20 totally reflects and guide it to an objective 8 of 90 deg. upward microscope 4 for further magnification; then, a CCD camera 12 forms an image. That is, the reflected light of a beam having irradiated the object 10 directly over a wide range is guided in a direction different from that of incident light for image formation. Therefore, a wide range of reflected light can be introduced into the lens 8, and a magnified image can be obtained regardless of direction of incident light and position of light source.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical inspection device suitably used for visual inspection and surface inspection of minute objects such as miniature drills.

0002

2. Description of the Related Art FIG. 3 shows a conventional example of a miniature drill visual inspection device. The miniature drill to be inspected by this device has a very small outer diameter, for example less than 1 mm in diameter.

[0003] When attempting to conduct an external appearance inspection of such a small-diameter inspection object, a method is used in which a CCD camera captures an enlarged image using a microscope or the like, as shown in the figure. That is, the light beam emitted from the light source 2 is transmitted to the microscope 4.
The light beam is reflected at 90 degrees by the half mirror 6 in the interior, and is further guided to the inspection object (drill) 10 by the objective lens 8. CCD camera 12
It is designed to focus light on

0004

However, in the inspection apparatus, in order to obtain the necessary magnification with the objective lens 8, the objective lens 8 must be brought close to the inspection object 10, and there is no There is no space available for providing another light source, and therefore, the light rays irradiated onto the inspection object 10 must also pass through the objective lens 8. Then, the light beam passing through the objective lens 8 is transmitted to the curved inspection object 1.
When irradiating to 0, only the light beam reflected at a specific angle is introduced into the objective lens 8, and there is a problem in that only an image of an extremely narrow range can be obtained, as shown by hatching in FIG. In order to obtain reflected light over a wide range, it is also possible to arrange the light source on a cylindrical surface centered on the inspection object 10, but as mentioned above, since the objective lens 8 and the inspection object 10 are arranged close to each other, , it is difficult to obtain the necessary space.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an inspection device that can irradiate a wide range of light beams onto an object to be inspected.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a light source, a diffuser plate provided between the light source and an object to be inspected to diffuse the light rays, and a diffuser plate that magnifies the rays reflected by the object to be inspected. An objective lens is provided between the diffuser plate and the object to be inspected to form an image on the light-receiving means, and allows the light rays to pass through, and also directs the light rays reflected by the object to be inspected in a direction different from the direction of incidence of the light rays from the light source. It consists of a half mirror that reflects the light.

[0007]

[Operation] According to the above structure, the light beam emitted from the light source is diffused over a wide range by the diffuser plate, and then directly irradiated onto the object to be inspected. Further, the light beam reflected by the surface of the object to be inspected is guided by a half mirror in a direction different from that of the incident light, and then enters the light receiving means by the objective lens.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. In the figure, parts common to the conventional example are given the same reference numerals.
The explanation will be omitted.

The light beam emitted from the light source 2 is guided near the inspection object 10 by an optical fiber 14, and is passed through a diffuser plate 16.
After the irradiation range is expanded by , the light passes through the half mirror 6 and is irradiated to the inspection object 10 from the side. Further, the half mirror 6 is arranged at an angle of about 45 degrees with respect to the axis of the inspection object, and is adapted to reflect the light beam reflected by the inspection object 10 in a direction parallel to the axis of the inspection object 10. ing. Further, at a position facing the half mirror 6, a reflecting mirror 18 is disposed line-symmetrically with the half mirror to reflect the reflected light 90° laterally,
Further, the light beam reflected by this reflecting mirror 18 is totally reflected by a prism 20 and guided upward by 90 degrees to the objective lens 8 of the microscope 4, and further, after being magnified,
The image is formed on a CCD camera 12.

That is, in the above optical system, a light beam irradiated onto a wide range of the inspection object 10 from the back side of the half mirror 6 is transmitted through the half mirror 6 to the reflecting mirror 18 to the prism 2.
The light is guided in a direction different from that of the incident light via a reflection path passing through 0, and is imaged by the CCD camera 12.

In the above optical system, the light beam to be irradiated onto the inspection object 10 is diffused by the diffusion plate 16, so that it is irradiated onto the inspection object 10 over a wide range or from various angles. Since the irradiation is directly onto the inspection object 10 without passing through the
Even if the curved surface is curved, the objective lens 8 can introduce light rays reflected over a wide range, as shown by hatching in FIG. In addition, the light beam reflected on the surface of the inspection object 10 is guided in a direction different from the incident light and then enters the objective lens 8 of the microscope 4, so it is not affected by the direction of the incident light or the position of the light source. , an enlarged image can be obtained.

In the above optical system, various reflection means are used to determine the reflection path of the light beam, but in response to changes in the relative positions of the light source 2 and the objective lens 8, Change the guiding direction or reflector 1
8. Of course, the configuration, arrangement, or number of prisms 20 may be changed to change the reflection path.

[0013]

[Effects of the Invention] As is clear from the above explanation, the present invention has the following advantages:
Since there is a diffuser plate between the light source and the object to be inspected,
After the light rays emitted from the light source are diffused over a wide range by a diffuser plate, they are irradiated onto the object to be inspected from various directions, and the light rays reflected over a wide range can be introduced into an objective lens for measurement. In addition, the light beam reflected from the surface to be inspected is guided in a direction different from the incident light by a half mirror, and then
Since the light enters the light receiving means through the objective lens, the light source and the objective lens can be arranged without sacrificing the degree of freedom in mutual arrangement. Therefore, arbitrary illuminance and magnification can be obtained for efficient inspection. It has the effect of being able to.

[Brief explanation of drawings]

FIG. 1 is a side view of an embodiment of the invention.

FIG. 2 is an explanatory diagram of a range in which a light beam is irradiated onto an inspection object by the apparatus of FIG. 1;

FIG. 3 is a side view of a conventional example.

FIG. 4 is an explanatory diagram of a range in which the inspection target is irradiated with a light beam by the apparatus of FIG. 3;

[Explanation of symbols]

2 Light source 6 Half mirror 10 Object to be inspected 12 CCD camera 14 Optical fiber 16 Diffusion plate 18 Reflector 20 Prism

Claims (1)

[Claims] 1. A light source, a diffusion plate disposed between the light source and an inspection object to diffuse light rays, an objective lens for magnifying the light rays reflected by the inspection object and forming an image on a light receiving means, and the diffusion plate disposed between the light source and the inspection object. An optical system characterized by comprising a half mirror interposed between the plate and the object to be inspected to allow the passage of light rays and to reflect the rays reflected by the object to be inspected in a direction different from the incident direction of the rays from the light source. Inspection equipment.