JPH0310106A - Image pick up apparatus - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of the amount of light at a low cost and to obtain a clear image by utilizing the central part of a reflecting mirror, and projecting light on a subject approximately vertically. CONSTITUTION:A light projector 2 is set at any of the height of (a), (b) or (c) in corre spondence with the size, the shape and the like of a subject 3. The image is picked up with an image sensing device 5. The light from a light source is projected on a mirror surface 1a of a reflecting mirror 1 from the light projector 2. The light is reflected downward from the mirror surface 1a. The light is transmitted through a half mirror 4 and projected on the subject 3. At this time, the central part of the mirror surface 1a can be especially utilize effectively. Therefore, the vertically project ed light can be readily obtained. Variation in projecting angle can be increased. The light projected on the subject 3 is received 5. At this time, the half mirror 4 efficiently transmits the light from the light projector 2 onto the subject. The reflected light from the subject 3 is efficiently reflected with the half mirror 4 in the direction of the image sensing device 5. As a result, the image corresponding to the projecting angle to the subject 3 is imparted to the image sensing device 5. The surface uneven ness of the subject 3 is obtained as the clear image having definite contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device, and particularly to an imaging device that can obtain a contrasting image of irregularities on the surface of an object to be imaged.

[Conventional technology]

2. Description of the Related Art Conventionally, there is an image pickup apparatus of this type as shown in FIG.

This I static image device has a central opening 10a that protrudes downward,
A nonlinear conical reflector 10 having a concave mirror surface tab on its periphery, a floodlight 1z such as a fiber ring illuminator that emits light inward in the horizontal direction toward the mirror surface 10b of the reflector lO, and a reflector 1z. 10 and the central opening 1 of the reflector IO
A lens 1 that condenses the reflected light of the imaged object 12 that has passed through 0a
3, and an image sensor 14 that converts the received light into an electrical signal.

The light from the projector 11 is reflected by the mirror surface 10b of the reflecting plate 10, and then irradiated onto the static image object 12 at various angles. For example, when the projector 11 is installed at a height of a, the object 12 to be imaged is irradiated with light in an oblique direction, and at a height of C, the object 12 to be imaged is irradiated with light in a substantially perpendicular direction. , b is in between.

Therefore, if the reflected light from the imaged object 12 is received by the image sensor 14, the unevenness of the surface of the imaged object 12 can be obtained as an image with contrast.

(Problems to be Solved by the Invention) However, a drawback of the above imaging device is that since the reflection plate 10 has the opening 10a in the center, it is difficult to obtain light irradiated perpendicularly to the object to be imaged 12.Object to be imaged 12 If you try to make the light irradiation angle closer to vertical, the projector 11 should be
The center opening 1 of the reflector 10 is installed at a height of
Although it is necessary to reduce the outer diameter of 0a, this poses a problem in that the amount of light that enters the central opening 10a by 3M is reduced. As a result, the amount of light received by the image sensor 12 decreases, and the periphery of the image becomes insufficient in light amount, requiring a special optical design to avoid this problem. In other words, a commercially available camera cannot be used as an inspection device, leading to an increase in costs. In addition, since it is difficult to adjust the amount of light received by the imaging element 12 using the aperture on the light receiving side, it is essential to adjust the light 1811 on the light emitting side. Therefore, as a light source, a strobe, which has a large amount of light but is difficult to adjust, is used. There were various problems such as unusability.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an imaging device that is inexpensive, allows easy adjustment of the light beam 13', and is capable of obtaining clear images.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a nonlinear conical reflecting mirror with a protruding central portion and a concave mirror surface on the periphery; A projector that emits light inward, an object to be imaged placed on the central axis in the protruding direction of the reflecting mirror, and an angle θ between the object to be imaged and the reflecting mirror with the central axis of the reflecting mirror. ,
an anti-Jlf plate that transmits light from the reflecting mirror and reflects light from the object to be imaged;
It includes an imager disposed on the optical axis closest to the image object, passing through a point where it intersects with the reflection surface on the image object side and forming an angle θ with the reflection plate.

(Function) That is, since there is no need for light to pass through the center of the reflecting mirror, it is possible to utilize the center of the reflecting mirror to irradiate the object with light almost perpendicularly. In other words, variations in the light irradiation angle can be increased and clearer images can be obtained. Furthermore, since there is no need to receive light through a small aperture, the problem of insufficient amount of received light is eliminated, and the amount of received light can be adjusted on the image pickup device side. Therefore, a strobe, which could not be used in the past, can be used as a light source, and since there is no need for special optical design, it is also possible to use a commercially available camera as an image pickup device.

〔Example〕

FIG. 1 shows an example of an imaging device according to the present invention.

In the figure, reference numeral I denotes a nonlinear conical reflecting mirror installed with the central axis SI in the vertical direction, with a central portion protruding downward and a concavely curved mirror surface 1a formed around the central portion. Reference numeral 2 denotes a floodlight such as a known fiber optic illuminator, in which a large number of optical fibers 2a are held by a ring-shaped fiber guide 2b. The tip of each optical fiber 2a is exposed on the inner peripheral surface of the fiber guide 2b, and the light source (
The light sent from the fiber bundle 2c (not shown) is
Light is irradiated horizontally inward from the tip of each optical fiber 2a toward the mirror surface 1a of reflection vlI.

3 is an object to be imaged such as an electronic element or a circuit board, and the reflection vl
The reflecting mirror 1 is located between the reflecting mirror 1 and the 6-field image object 3, which is disposed above the central axis S of 1 and facing the mirror surface 1a.
A half mirror 4, which is a reflecting plate, is installed so as to form an angle θ with the central axis S1. This half mirror 4 is a known one, and has a reflective surface 4a on the lower surface side so that most of the light from above is transmitted and most of the light from below is reflected.
is formed. The central axis S of the reflecting mirror 1 passes through a point R where the half mirror 4 intersects with the reflecting surface 4a of the three objects to be imaged, and is on the optical axis S2 forming an angle θ with the half mirror 4 on the side of the object to be imaged 3. , an imaging device 2'i5 such as a CCD camera is installed.

Incidentally, the inclination angle θ of the half mirror 4 is set within an angular range in which the light from the reflecting mirror l can be efficiently transmitted to the imaged object 3 side, and the reflected light from the imaged object 3 can be efficiently reflected on the reflective surface 4a. Must be set. It is desirable for the angle θ to be set at the height 45' in terms of positioning accuracy between the half mirror 4 and the image pickup device 5.

Next, a method of using the imaging device according to the present invention will be explained.

First, reflector 1. Floodlight 2. Imaged object 3. half mirror
4 and the image pickup device 5 are installed in a positional relationship as shown in FIG. Then, the projector 2 is installed at a height of a, b, or C depending on the size and shape of the object 3 to be imaged, and the image at that time is projected by the image pickup device 5. The light from the light source is irradiated from the projector 2 onto the mirror surface 1a of the reflecting mirror 1, reflected downward by the mirror surface 1a, transmitted through the half mirror 4, and irradiated onto the object 3 to be imaged.

When the projector 2 is installed at a height of a, the light is directed toward the object 3 to be imaged.
When installed at a height of C, it is irradiated in a vertical direction, and when installed at a height of b, it is irradiated in an intermediate direction. In particular, since the central portion of the mirror surface la can be effectively utilized, vertical irradiation light can be easily obtained and variations in irradiation angles can be increased.

The light irradiated onto the object to be imaged 3 is reflected by the surface of the object to be imaged 3, reflected by the reflective surface 4a of the half mirror 4, and then received by the imager 5. At this time, the nof mirror 4 efficiently transmits the light from the projector 2 to the object 3 to be imaged, and
The reflected light is efficiently reflected in the direction of the imager 5. As a result, an image corresponding to the irradiation angle to the object 3 is projected on the first imager 5, and a clear image with contrast of the unevenness of the surface of the object 3 is obtained.

Since the reflected light from the imaged object 3 is received by the imager 5 without passing through a narrow aperture, the amount of light received by the imager 5 is larger than in the conventional case (Fig. 2), and the amount of light at the imager 5 is Adjustment is possible. Therefore, in addition to the conventionally used halogen lamp as a light source, there is a large amount of light, but the light ff1il! Allows use of strobes that are difficult to adjust.

In addition, since the imager 5 can obtain an image without uneven light,
No special optical design is required, and a commercially available CC can be used as an imager.
A D camera etc. can also be used.

This enables significant cost reduction.

Furthermore, in the past, the amount of light was adjusted on the light projecting side, which caused a problem of color temperature change, but the present invention solves this problem.

Note that the mirror shape of the reflection txt is similar to the shape of a conventional reflector, and it is sufficient that it reflects at least the light from the projector 2 in the direction of the central axis S1.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to irradiate light almost perpendicularly to the object to be imaged by utilizing the central part of the reflecting mirror, and therefore it is possible to increase variations in the irradiation angle of light. , a clearer image can be obtained. In addition, since there is no need to receive light through a small aperture,
This solves the problem of insufficient light reception and eliminates the need for special optical design or adjustment of the light reception on the light emitting side. Therefore, it is possible to use a strobe as a light source, which could not be used in the past, and it is also possible to use a commercially available camera as an imager.
．． It has the advantage of being inexpensive to configure.

[Brief explanation of drawings]

FIG. 1 is a layout diagram of an imaging device according to the present invention, and FIG. 2 is a layout diagram of a conventional imaging device. l... Reflector, 1a... Mirror surface, 2... Floodlight, 3
...1st object to be imaged, 4...half mirror (reflector),
4a... Reflective surface, 5... Imager.

Claims (1)

[Claims] A nonlinear conical reflecting mirror with a protruding central portion and a concave mirror surface on the periphery, and a reflecting mirror that irradiates light inward toward the mirror surface from a direction perpendicular to the central axis of the reflecting mirror. A projector, an object to be imaged placed on the central axis in the protruding direction of the reflecting mirror, and an angle θ between the object to be imaged and the reflecting mirror with respect to the central axis of the reflecting mirror, and light from the reflecting mirror. a reflector that transmits the light and reflects light from the object to be imaged, and a side of the object to be imaged that forms an angle θ with the reflector through a point where the central axis of the reflector intersects with the reflecting surface of the reflector on the object side. An imaging device comprising: an imager disposed on the optical axis of the image sensor;