JPH10246857A - Oblique light illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify and miniaturize an entire device by fixing or positioning vertical illumination put on the optical axis of an objective lens and a spatial filter so that various kinds of deflected oblique light illumination may be obtained. SOLUTION: The illumination emitted from the light source 5 of a vertical illuminator 7 is cast to a half mirror 2 and deflected downward by 90 deg., and further it is deflected to be illuminating light having various angles once more by the 1st spatial filter 4 optically positioned between the objective lens 1 and the device 7, and the illuminating light becomes deflected oblique light illumination luminous flux and vertically illuminates the surface of an examinee 9 through the lens 1. Furthermore, as for reflected light reflected from the examinee 9, the image-formation luminous flux 10 through an intermediate image- formation lens 3 positioned above the mirror 2 is formed into an image on an image-formation surface 11 by a TV camera, other sensor surface or an ocular optically positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to oblique illumination in combination with epi-illumination (coaxial) illumination of optical equipment.
By illuminating the test object obliquely, the configuration is simple,
Also relates to low-cost optical equipment.

[0002]

2. Description of the Related Art Conventionally, as a method of illuminating a test object and detecting an optical image, a vertical epi-illumination (coaxial, hereinafter the same) illumination method for illuminating from an optical axis of an objective lens or an optical axis of an objective lens is used. There is an oblique illumination device that performs oblique illumination from inside. In this vertical incident illumination, an optical image of a flat surface can be obtained, but a three-dimensional shape, a flaw, an edge, and the like formed on the surface of the test object are hardly provided with contrast, and a good optical image cannot be obtained. Therefore, as a method for obtaining a three-dimensional and good contrast optical image, there is a technique as disclosed in Japanese Patent Application Laid-Open No. 8-166514 as an oblique incidence illumination method for obliquely illuminating the optical axis of an objective lens. The external oblique incidence method includes a method in which a three-dimensional optical image can be obtained by using a circular or rod-shaped or a plurality of fiber light guides on the outer periphery of the objective lens.

[0003]

As described above, there is a method of obtaining an optical image by illuminating a test object. However, in a vertical incident illumination method of illuminating from an optical axis of an objective lens, an optical image having a flat surface is obtained. However, the three-dimensional shape, fine scratches, edges and the like formed on the surface of the test object were hardly contrasted, and a good optical image could not be obtained.

[0004] Therefore, to obtain a three-dimensional optical image with good contrast, an oblique incidence type oblique illumination system disclosed in Japanese Patent Application Laid-Open No. 8-166514 has been provided. As might be expected, the equipment tends to be complex and expensive. Also, oblique illumination with a fixed illumination angle may not be able to cope with a slight defocus of the objective lens. Further, in the configuration, the means for applying oblique illumination is to obtain a three-dimensional optical image by performing oblique illumination by arranging a plurality of circular or rod-shaped fiber light guides or the like on the outer periphery of the objective lens. Therefore, the above problem cannot be solved.

[0005] In addition, since the oblique illumination shape and the illumination angle are fixed, it is difficult to cope with an object that requires illumination at a delicate angle, and between the objective lens and the object. Due to the physical limitation, it may not be used due to attachment to the device or physical interference with the device. In addition, the oblique lighting device has a complicated configuration due to the arrangement of a plurality of fiber light guides, etc., and the number of parts increases, so it is natural that it is unavoidable to increase the size of the device. In addition, it had a high cost factor.

[0006]

The method of illuminating a test object according to the present invention has been made in order to solve the above-mentioned drawbacks and inconveniences. The oblique illumination system is configured so that various oblique illumination can be obtained by fixing or positioning the vertical illumination placed on the optical axis of the objective lens and the spatial filter.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The oblique illumination device according to the present invention has a structure in which a first spatial filter (4) capable of movable modulation, a half mirror (2), and an intermediate image forming lens (3) are provided above the objective lens (1). ), And the vertical epi-illumination device (7) incorporating the half mirror (2) is formed. Therefore, the illumination light emitted from the vertical epi-illumination device (7) is a half mirror (2). Can illuminate the test object (9) with the oblique illumination light beam (8) that has been deflected downward by 90 degrees and passed through the objective lens (1). An effective image forming light beam (10) passing through the image forming lens (3) can be sent to an image forming surface (11).

Further, the type in which the second spatial filter (12) is incorporated between the intermediate imaging lens (3) and the imaging surface (11) can have a function of increasing the detection resolution. . In addition, the first and second spatial filters (4, 4) are combined with the configuration method of the vertical epi-illumination device (7).
Since 12) is also formed functionally, the configuration is simple and the whole apparatus can be downsized.

[0009]

【Example】

Embodiment 1 An oblique illumination device according to Embodiment 1 of the present invention will be described with reference to the basic schematic configuration diagram shown in FIG. First, the figure shows an example in which the oblique illumination device according to the basic configuration of the present invention is applied to an optical device such as an object shape inspection machine or measurement device,
The illustrated basic configuration is such that a half mirror (2) for vertical epi-illumination is positioned above the objective lens (1), and an intermediate imaging lens (3) is further disposed above the objective lens (1). Half mirror (2) The first that can be moved and modulated near the bottom
A vertical filter (7) having a light source (5), a condenser lens (6) and the like is formed at a portion corresponding to the half mirror (2).

In this embodiment, the illumination emitted from the light source (5) of the vertical epi-illumination device (7) hits the half mirror (2) and is deflected downward by 90 degrees. Has a first optically positioned therein between the objective lens (1) and the vertical epi-illumination device (7).
The light is further deflected again by the spatial filter (4) into illumination light having various angles, and the illumination light becomes an oblique illumination light flux (8) and passes through the objective lens (1) to the surface of the object (9). Is vertically illuminated. In addition, the test object (9)
The reflected light reflected from the imaging light flux (1) through the intermediate imaging lens (3) positioned above the half mirror (2)
0) will form an image on the imaging plane (11) by means of an optically positioned TV camera or other sensor surface or eyepiece.

As described above, since the first spatial filter (4) that can be movably modulated is located near the upper half mirror (2) of the objective lens (1), the surface of the object (9) to be inspected has a feature. Depending on the state, the vertical epi-illumination can illuminate the light from the half mirror (2) at various angles by adjusting the first spatial filter (4) in and out. ) Surface shape and scratches,
Although it has a simple structure in which the oblique illumination light beam (8) corresponding to the state of the edge or the like can be applied to the object (9), it is possible to increase the image resolution to the image plane (11). is there.

Embodiment 2 Embodiment 2 will be described with reference to the configuration diagram shown in FIG. The basic configuration of the second embodiment is the same as that of the first embodiment, except that a second spatial filter (12) is provided above the half mirror (2), that is, at a position closer to the imaging plane (11).

In the first embodiment, a first spatial filter (4) is provided between the half mirror (2) and the objective lens (1) to enable the adjustment of the oblique illumination illumination light beam (8) so as to form a preferable image. Although an image is obtained, in the second embodiment, the second spatial filter (12) is connected to the intermediate imaging lens (3) and the imaging plane (11) in order to further increase the detection resolution. It is located between.

Therefore, in this embodiment, the oblique illumination light beam (8) having passed through the first spatial filter (4) is supplied to the objective lens (1), the test object (9), and the intermediate imaging lens (3). Is passed through the second spatial filter (12).
With this arrangement, the imaging light beam (10), which can perform finer and finer adjustments, can be connected to the imaging surface (11), so that a function of greatly improving image resolution can be provided.

Although each embodiment of the present invention has the above-described configuration, the first and second spatial filters (12) in the drawing are of a type capable of movable modulation, but may be of a fixed type. Absent. Further, the number of each spatial filter may be one, but may be plural, and furthermore, any of a forming position, an individual formula, a movable type, a number and the like are arbitrary and are not particularly limited.

[0016]

The oblique illumination device constituted by the optical apparatus according to the present invention is incorporated between the optical axis of the objective lens and the vertical epi-illumination device, so that the structure of the device is extremely simple, and The problem of physical interference with a test object, which is common in conventional oblique illumination installed on the outer periphery of an objective lens, can be solved. In addition, the illumination passing through the half mirror applied to the test object can be applied to the surface of the test object with various oblique illumination light beams by the first spatial filter having the movable modulation mechanism. The type in which the contrast can be easily provided, a preferable image-forming light beam can reach the image-forming surface, and the second spatial filter is added, has a function of further increasing the detection resolution.

Therefore, since the first and second spatial filters provided as an adjusting mechanism for effectively making the configuration of the epi-illumination device and the oblique illumination light beam and the image forming light beam have a functional arrangement, the configuration is extremely simple. Therefore, the size can be easily reduced, and the price can be provided at a lower price than the oblique illumination method having a complicated shape as in the related art.

[Brief description of the drawings]

FIG. 1 is a basic schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Objective lens 2 ... Half mirror 3 ... Intermediate imaging lens 4 ... 1st spatial filter 5 ... Light source 6 ... Condenser lens 7 ... Vertical epi-illumination device 8 .... • Oblique illumination light beam 9: object to be inspected 10: image forming light beam 11: image forming surface 12, second spatial filter

Claims (2)

[Claims] An oblique light illuminating device in an optical apparatus is provided with a vertical drop formed by associating a light source with a half mirror disposed above an objective lens in the order of a half mirror, an intermediate imaging lens, and an imaging surface. An oblique illumination device having an oblique illumination device and having a first spatial filter between an objective lens and a half mirror. 2. The oblique illumination device according to claim 1, wherein a second spatial filter is interposed between the intermediate image forming lens and the image forming plane.