JPH10153738A - Optical image recognition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical image recognition device with a lighting mechanism, which can obtain lighting numerical apertures made to correspond to photographic lenses by the illumination switching of a light source without being equipped with any mechanical movable part, and provides dark-field lighting by the illumination switching of the light source as well. SOLUTION: This image recognition device is equipped with the lighting mechanism composed of a multi-layered circularly-sectioned optical fiber guide 24 having its 1st layer guide 24a and 2nd layer guide 24b formed of many optical fibers, a 1st light source 21 and a 2nd light source 22 which are provided corresponding to the 1st layer guide 24a and 2nd layer guide 24b so that lights are inputted to the 1st layer guide 24a and 2nd layer guide 24b separately and the light output of the optical fiber guide 24 is projected on a body 29 through lighting lens systems 25, 26, and 28, and an illumination switching device which turns on the 1st light source 21 and 2nd light source 22 together or separately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical image recognition apparatus for photographing an object while illuminating the object and recognizing the shape and position of the object as a photographed image.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a semiconductor device is used.
An image recognition device for factory information (FA) is used to recognize the shape, position, and the like of the image.

In such an image recognition apparatus, light from a light source is projected onto an object (wafer) through an illumination lens system, and reflected light from the object is received through a photographing lens system. In other words, a TV (television) camera for photographing while illuminating a wafer as an object is provided, and the configuration and the position of the wafer are recognized from the display image of the TV camera.

In the image recognition apparatus as described above, when the brightness of the illumination is prioritized, a critical illumination for directly forming an image of the light source on the object plane is introduced. For example, an image such as a filament of a lamp is formed. For this reason, illumination unevenness increases and a photographing lens having a high magnification must be used.

On the other hand, a color illumination is widely known as an illumination method in which an illumination unevenness is small and a low magnification photographing lens can be used. FIG. 4 is an optical system diagram of an image recognition apparatus in which a color illumination mechanism is incorporated. This image recognition apparatus uses a light from a light source 11 to collect light from a collector lens 12 and a condenser lens 1.
An illumination lens system for condensing light at 3 and illuminating the object 15 as flat light with a condenser lens 14 is provided.

The condenser lens 1 which functions as an objective lens with the reflected light of the object 15 illuminated as described above.
4 is provided with a photographing lens system which reflects the reflected light from a beam splitter 16 through a focusing lens 17 to a CCD 18 of a TV camera.

On the other hand, since the optimum numerical aperture (NA) of the taking lens is set according to its magnification, a clear photographed image cannot be obtained unless the numerical aperture is not too large. Therefore, in the above-described image recognition apparatus for color illumination, in order to match the numerical aperture of the illumination with the numerical aperture (NA) of the photographing lens, the diaphragm 1 is used for the illumination lens system.
9, the aperture 19 is adjusted to change the numerical aperture.

FIG. 5 shows structural means for performing dark-field illumination in an image recognition apparatus for color illumination. That is,
The illumination lens system is provided with a light-shielding means for inserting and removing a light-shielding plate 20 for shielding the illumination corresponding to the numerical aperture of the taking lens. When the light-shielding plate 20 advances to the illumination optical path, the object 15 is illuminated obliquely from the outer periphery of the condenser lens 14.

Due to this illumination, the reflected light from the object 15 does not return to the numerical aperture of the taking lens by specular reflection, so that only the outline of the object 15 becomes bright and dark-field illumination.

[0010]

The above-described image recognition apparatus often requires mechanical durability. For example, an image recognition device for FA is required to have durability to withstand 10 million or more recognition operations.

For this reason, a configuration in which the numerical aperture of illumination is changed by a mechanical diaphragm 19, as in the above-described conventional image recognition apparatus, is not desirable. The same can be said for the light shielding plate 20 that performs dark field illumination.

When the numerical aperture is changed at a high speed corresponding to a plurality of photographing lenses, the response becomes slow with a mechanical diaphragm 19, and it is not preferable to provide a mechanical movable part from this viewpoint.

In view of the above situation, the present invention can provide an illumination numerical aperture corresponding to a plurality of photographing lenses by switching the light source on and off without providing a mechanical movable part. An object of the present invention is to provide an optical image recognition device having an illumination mechanism that enables dark-field illumination by switching lighting.

[0014]

In order to achieve the above object, an image recognition apparatus of the present invention projects light of a light source onto an object through an illumination lens system, and receives reflected light of the object through a photographing lens system. In an image recognition device configured to recognize a shape, a position, and the like of an object, an optical fiber guide having a circular cross section of a multi-layer in which each layer is formed by a number of optical fibers
A plurality of light sources provided corresponding to the respective layers so as to separately input light to each layer of the optical fiber guide and project the light output of the optical fiber guide to an object through an illumination lens system, and a plurality of light sources. The lighting device is provided with an illumination mechanism including light source lighting switching means for lighting all or a part of the light source.

[0015]

When all of the light sources are turned on by the light source lighting switching means, light can be output from all the fiber layers of the optical fiber guide, whereby illumination light corresponding to a photographing lens having a large numerical aperture can be obtained. An object is illuminated via an illumination lens system.

When a part of the light source is turned on by the light source lighting switching means and light is output from the fiber layer located at the center of the optical fiber guide, the illumination light corresponding to the photographing lens having a small numerical aperture is illuminated. An object is irradiated via a lens system.

If a part of the light source is turned on by the light source lighting switching means and light is output from the fiber layer located around the optical fiber guide, the illumination light has a numerical aperture larger than the numerical aperture of the photographing lens. This illumination light is applied to the object via the illumination lens system to provide dark field illumination.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an optical system diagram of the image recognition device shown as the first embodiment. As shown in the figure, the image recognition device includes a first light source (lamp) 21 and a second light source (lamp) 22, and the first and second light sources can be switched on and off by a lighting switching device 23. I have. That is, switching is performed so that both the first light source 21 and the second light source 22 are turned on, only the first light source 21 is turned on, and only the second light source 22 is turned on.

The lighting light of the first light source 21 and the second light source 22 is guided to an illumination lens system via an optical fiber guide 24. As shown in FIG. 2, the optical fiber guide 24 is configured as an elongated shape composed of an optical fiber bundle having a circular cross section composed of two layers. That is, a first layer guide 24a that bundles a large number of optical fibers into a central layer.
Similarly, a second layer guide 24b is formed by bundling a large number of optical fibers to form an outer layer. The light output end face 24c of the optical fiber guide 24 is set to have a size corresponding to the required numerical aperture of the taking lens.

The optical fiber guide 24 is
The light of the first light source 21 enters the first layer guide 24a,
The first and second light sources are connected so that the light of the light source 22 enters the second layer guide 24b.

Guided by an optical fiber guide 24,
The light output from this guide 24 is
5. An object 29 is irradiated through an illumination lens system including a condenser lens 26, a beam splitter 27, and a condenser lens 28.

The light reflected from the object 29 passes through a condenser lens 28 serving as an objective lens and is reflected by a beam splitter 27. Then, the light reflected by the beam splitter 27 is changed to another beam splitter 3.
0 and C of the first TV camera 32 through the imaging lens 31
The light is made incident on a CD (image pickup device) 33 and the light reflected by the beam splitter 30 is passed through an imaging lens 34 to a second
To the CCD (image pickup device) 36 of the TV camera 35 of FIG.

The first TV camera 32 receives light from the imaging lens 31 having a small magnification as a photographing lens, and performs photographing.
The second TV camera 35 receives light from an imaging lens 34 having a large magnification as a photographing lens to photograph.

Next, the image recognition operation will be described. When recognizing the object 29 with a large magnification, the first light source 21 and the second light source 22 are turned on by the lighting switching device 23. As a result, light having a large numerical aperture output from the first layer guide 24a and the second layer guide 24b of the optical fiber guide 24 enters the object 29 through the illumination lens system.

In this case, an image is taken through an imaging lens 34 having a large numerical aperture as an image taking lens, and the second TV camera 3
By photographing at 5, the image can be recognized from the displayed image.

When the object 29 is recognized at a small magnification, only the first light source 21 is turned on by the lighting switching device 23. As a result, light is output only from the first layer guide 24a of the optical fiber guide 24, so that the object 29 is irradiated with illumination light having a small numerical aperture.

In this case, the image can be recognized from the displayed image by taking an image with the first TV camera 32 through the imaging lens 31 having a small numerical aperture as an imaging lens.

When performing dark field illumination, only the second light source 22 is turned on by the lighting switching device 23. As a result, light is output only from the second layer guide 24b of the optical fiber guide 24, and the object 2 is irradiated with the illumination light of this light output.
9 is illuminated.

In this case, illumination light having a numerical aperture larger than the required numerical aperture of the photographing lens (the numerical aperture of the imaging lens 31) is incident on the object 29. Accordingly, the light reflected from the contour of the object 29 passes through the condenser lens 28, the beam splitters 27 and 30, and the imaging lens 31 and passes through the CCD 33.
And the outline is photographed by the first TV camera 32, so that the image can be recognized from the displayed image.

FIG. 3 is an optical system diagram of the image recognition apparatus shown as the second embodiment. This embodiment uses an optical fiber
The light output of the guide 24 is reflected by the beam splitter 42 through the condenser lens 41 and is irradiated on the object 29.

The reflected light of the object 29 passes through the beam splitter 42, and then passes through the objective lens 43, the beam splitter 30, and the imaging lens 31 to the first TV camera 32.
And the reflected light reflected by the beam splitter 30 is incident on the CCD 36 of the second TV camera 35 through the imaging lens 34.

The other components are the same as those of the first embodiment, and the same members are denoted by the same reference numerals. In the second embodiment, the condenser lens 41 and the objective lens 4
3 is provided separately, and the image recognition operation is the same as that of the first embodiment.

While the preferred embodiment of the present invention has been described above, it is possible to provide three or more photographing lens systems having different magnifications and photograph an object according to each magnification to recognize an image.

In this embodiment, the optical fiber guide 2 is provided corresponding to each of the photographing lens systems having different magnifications.
The number of layers may be increased, and a plurality of light sources for inputting light to each of the optical fiber guides 24 may be provided, and the lighting of these light sources may be switched.

[0035]

As described above, according to the image recognition apparatus of the present invention, the object illumination can be switched to the optimum numerical aperture for the taking lens by switching the lighting of a plurality of light sources. The image recognition device has excellent durability.

Since an optical fiber guide is used,
There is no restriction on the bending or distance of the optical path between the light source and the illumination lens system, which is advantageous for device design.

Further, since the dark field illumination can be performed by switching the lighting of the light source, a practical image recognition apparatus can be provided such that there is no need to separately provide a component for dark field illumination.

[Brief description of the drawings]

FIG. 1 is an optical system diagram of an image recognition device shown as a first embodiment.

FIG. 2 is a partial perspective view showing a cross section of the optical fiber guide.

FIG. 3 is an optical system diagram of an image recognition device shown as a second embodiment.

FIG. 4 is an optical system diagram of a conventional image recognition device incorporating a color illumination.

FIG. 5 is an optical system diagram showing dark field illumination of the above-described conventional image recognition device.

[Explanation of symbols]

 Reference Signs List 21 first light source 22 second light source 23 lighting switching device 24 optical fiber guide 24a first layer guide 24b second layer guide 27 beam splitter 28 condenser lens 29 object 30 beam splitter 31 imaging lens 33 CCD 34 Image lens 36 CCD

Claims (1)

[Claims] 1. An image recognition apparatus configured to project light from a light source onto an object through an illumination lens system, receive reflected light from the object through a photographing lens system, and recognize the shape, position, and the like of the object. An optical fiber guide having a circular cross section of a multilayer formed by an optical fiber;
A plurality of light sources provided corresponding to the respective layers so that light is separately input to each layer of the guide, and the light output of the optical fiber-guide is projected onto an object through an illumination lens system, and all or a part of the plurality of light sources An optical image recognition device comprising an illumination mechanism including light source lighting switching means for lighting a light source.