JP2016130717A - Spherical surface inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide vertical illumination or transmitted illumination spherical surface inspection device that implements an appearance inspection of an entire surface or part of an inspected surface of an inspected member including a surface with a spherical or aspherical surface with a wide field of view and high accuracy.SOLUTION: A vertical illumination spherical surface inspection device has: an image observation unit 90c that includes an objective lens 3 creating a primary image of an inspected surface 1b of an inspected member 1 as a telecentric real image or virtual image, an objective lens support base 90b, a set having an image relay lens 4 and image formation lens 5 relaying the primary image to be created by the objective lens, and creating a secondary image, and an image pick-up element 6 attached at a secondary image formation position and moves along an inspection optical axis; and a vertical illumination projection unit 90d that, due to an arrangement of a light splitting deflection mirror 7, allows a light flux from a circular light source 11 arranged on a projection light optical axis 21 to be formed at a focus position of the objective lens as a circular light source image. A size of the circular light source or a numerical aperture illuminating the inspected member, that is, an illumination NA is variable.SELECTED DRAWING: Figure 1

Description

  The present invention is capable of observing and observing the whole or part of the test surface of a test member having a test surface including a spherical surface or an aspherical surface on at least a part of the surface with a wide field of view with high accuracy. The present invention relates to an epi-illumination or transmission illumination spherical surface inspection apparatus capable of observing a spherical surface having a wide range of curvature radius and having a large cone angle when viewing the outer diameter of the surface to be measured from the center of curvature of the surface to be measured as a substantially planar image.

  In the inspection of mold lenses and steel balls made of lenses or metal lenses made of optical glass or resin, scratches and dirt on the surface of the spherical surface of the member to be tested, small surface defects called craters, or processing defects Therefore, there is a need for means and devices that can inspect a large range of undulations, blade traces, and the like on a mold spherical surface with high accuracy.

  Conventionally, spherical surface inspection involves irradiating various types of illumination light on the surface of the spherical surface and visually observing it using the naked eye or a loupe while moving the spherical surface. However, skillful skills were necessary, and it was not easy for everyone. Furthermore, there is a defect that the size of the defect cannot be measured even though the presence of the defect can be recognized by visual inspection. In addition, spherical inspection using a microscope has problems such as the focus range is different between the apex and the periphery of the sphere, so that the observation range is narrow and the spherical surface cannot be inspected collectively, and depending on the illumination method, the types of defects that can be observed are limited. .

In order to solve such problems, there are spherical surface inspection devices disclosed in Patent Literature 1, Patent Literature 2, and Patent Literature 3 as devices for inspecting a spherical surface.
The spherical inspection apparatus disclosed in Patent Document 1 uses a transmission microscope as a basic optical system, projects a small scattered circular light source (hereinafter referred to as a circular light source) on the focal position of a lens to be examined, and uses an illumination light beam from a circular light source image. Illuminate the entire spherical surface of both sides of the test lens. The illumination light that has passed through the lens to be examined becomes an afocal beam and enters the imaging optical system that is approximately telecentric on both the object side and the imaging side, and is imaged by the camera placed at the imaging position of the imaging optical system. This is a transmitted illumination spherical surface inspection device that creates a test surface image on a surface. The spherical inspection apparatus can represent a spherical surface close to a planar image even if there is a difference in height between the vertex and the periphery of the surface to be examined. In addition, projections with different focal lengths and numerical apertures project a small circular light source at the focal point of the lens to be tested for differences in focal length, center thickness, curvature radius, outer diameter, etc. We were able to cope with a wide range by preparing lenses. However, since it was necessary to illuminate the lens to be examined, it could not be used for a lens mold mold or a steel ball whose material is a metal. Patent Document 1 is a reference that describes a basic optical technique for expressing a spherical surface as a fine image close to a flat surface and a technique for dealing with a wide range of differences in the radius of curvature of a spherical surface to be examined.

  The epi-illumination spherical surface inspection device disclosed in Patent Document 2 projects a small circular light source as a circular light source image on the focal point of an objective lens, and illuminates the spherical surface by matching the center of curvature of the spherical surface with the circular light source image. This is an epi-illumination spherical surface inspection device that projects the reflected light from the surface of the spherical surface to be imaged onto the image sensor with an objective lens and an imaging lens. Detailed description will be made after the description of Patent Document 3, since Patent Document 3 is a prior art that is the basis of Patent Document 2 and other prior art of an epi-illumination spherical inspection apparatus.

Patent Document 3 is disclosed as a spherical epi-illumination spherical surface inspection device having a large radius of curvature, and describes the following three techniques.
1 and 2 showing a specific configuration of the claims of Patent Document 3, and the positional relationship between the objective lens and the imaging lens of the claims, the image side focal point of the objective lens and the object side focal point of the imaging lens. And the optical position where the test sphere is installed is shown in FIG. 3 and a configuration in which the test spherical surface is installed (hereinafter referred to as a telecentric configuration, but this configuration does not necessarily form a telecentric image). The third embodiment is composed of three techniques, which are different from the third embodiment and described in FIGS. 4 and 5.

1 and FIG. 2 of Patent Document 3 (hereinafter, the configuration of the claims) is an objective lens that also serves as a projection lens as a circular light source in which a circular slit is arranged on a diffusion plate illuminated by a lamp, and the optical axis of the objective lens. The projected spherical surface is illuminated with a light beam from the circular light source image after being projected to an arbitrary position on the top and matching the center of curvature of the spherical surface with the circular light source image. The reflected light from the subject spherical surface follows the same optical path as the illumination light, passes through the objective lens, and returns to the circular light source direction, but in a direction perpendicular to the optical axis of the objective lens by a light splitting deflection mirror disposed between the circular light source and the objective lens. Deflected. An imaging lens is disposed on the deflected optical axis, and an epi-illumination spherical surface inspection device is disclosed in which an image of a spherical surface to be examined is formed on a sensor by combining the imaging lens and an objective lens.
The configuration of FIG. 3 (hereinafter referred to as Example 1) is the same as the configuration of the objective lens and the imaging lens with the illumination system as shown in FIG. The test sphere is placed at the focal position of the objective lens, a circular light source image is projected on the center of curvature of the test sphere, and the test sphere is inspected with the light beam from the circular light source image.

  4 and 5 (hereinafter referred to as Example 2) is also a structural example, and the focal position of a newly added condensing (projecting) lens with the telecentric optical configuration of the objective lens and the imaging lens as in FIG. A circular light source is disposed on the objective lens so that an afocal light beam is incident on the objective lens. In Example 2, spherical inspection is performed by matching the center of curvature of a spherical surface to be tested with a circular light source image formed at the focal position of the objective lens. In this case, the light directed toward the center of curvature of the test spherical surface follows the incident optical path after being reflected by the test spherical surface, and proceeds in parallel to the optical axis of the objective lens after passing through the objective lens, as in the case of incidence. Then, after being deflected by the half mirror, it enters the imaging lens and forms an image of the test spherical surface by combining the objective lens and the imaging lens.

  When the three configurations described in Patent Document 3 are classified, the configuration of the claims is to align the center of curvature of the test spherical surface with the circular light source image projected on an arbitrary position of the optical axis of the objective lens, and the configuration of Example 1 is the objective lens. The test spherical surface is placed at the focal point and a circular light source image is projected at the center of curvature. The configuration of the second embodiment matches the focal point of the objective lens, that is, the circular light source image, with the center of curvature of the test spherical surface. In other words, although there is a difference between the configuration of the first embodiment in which the test spherical surface is at the focal point of the objective lens and the configuration of the second embodiment in which the test spherical surface is not at the focus of the objective lens, the light source is centered on the curvature of the test spherical surface. The point at which the image is projected is the same.

  Patent Document 2 is a modification of Example 2 of Patent Document 3 as far as FIG. 1 and FIG. Although the optical position of the test sphere is not described in the proposed optical system in the claims of Patent Document 3, from the figure, Patent Document 2 shows that the center of curvature of the test sphere matches the focal position of the objective lens. It is understood that this is the intention. The configuration of Patent Document 2 provides a degree of freedom in the distance between the objective lens and the imaging lens by not fixing the objective lens and the imaging lens in a telecentric arrangement from the configuration of Example 2 of Patent Document 3, and the imaging lens. It can be said that the aperture stop placed at the focal point of the aperture reduces the NA of the imaging light beam, that is, the numerical aperture, thereby increasing the contrast and depth of focus of the test spherical image, thereby widening the width of the test spherical curvature radius. In Patent Document 3, the fact that the light source is a point light source for visible light defines the size of the circular light source image and is an important description.

However, the epi-illumination spherical surface inspection devices of these patent documents have the following problems.
First, the size of the light source, which is a problem common to these patent documents, will be described. Patent Document 2 describes a point light source, and Patent Document 3 describes only a circular slit (light source), but does not describe what size it is. On the other hand, Patent Document 1 defines an illumination NA (shown in FIG. 4 of the present application) for illuminating one point of a test spherical surface from a circular light source image. An image made using a point light source is generally said to have high contrast but low resolving power. On the other hand, if the illumination NA is large, the resolving power increases. However, the illumination NA is not necessarily large. This is because it is important to have a certain value of illumination NA for each purpose of the device, both resolution and contrast. In the devices of Patent Documents 2 and 3, if the illumination NA is too large, the light reflected from the test spherical surface passes through the objective lens and the imaging lens as a large luminous flux, which causes a burden on the aberration correction of the imaging optical system design. If the diameter of the lens to be used is not increased, the amount of light around the image will be insufficient and vignetting will occur. Therefore, it is important to define the illumination NA in an inspection apparatus that obtains an image by irradiating illumination light. This problem is conspicuous in the case of spherical inspection with a small curvature radius and a large spherical angle (see FIG. 4 of the present application) because the illumination NA depends on the size of the circular light source and the curvature radius of the test spherical surface. Note that ½ of the cone angle formed by the outer diameter and the radius of curvature of the observable spherical surface is referred to as a viewing angle. Further, in this application, a half of the cone angle formed by the outer diameter and the radius of curvature with the test spherical surface is defined as the spherical angle.

Next, the malfunction for each apparatus will be described. In the transmitted illumination spherical surface inspection device described in Patent Document 1, when the inspection sphere is made of an opaque material such as metal, the inspection sphere cannot be inspected.
The epi-illumination spherical surface inspection apparatus described in Patent Document 2 has the same configuration as that of Example 2 of Patent Document 3 in which the subject spherical surface is not at the focal point of the objective lens. .
The defect of the epi-illumination spherical surface inspection device of Patent Document 3 will be described. Patent Document 3 discloses three techniques as described above, and each apparatus will be described below. However, in summary, there are problems relating to the range of the curvature radius of the inspectable sphere to be inspected related to the projection optical system of the light source. There is a problem with the quality of the obtained spherical image.

  In the configuration of Example 1 of Patent Document 3, the test spherical surface is placed at the focal position of the objective lens, and a circular light source image is projected on the center of curvature of the test spherical surface. Illuminate the point. The imaging of the test spherical surface at this time will be described with reference to FIG. For easy understanding, the focal length of the objective lens and the imaging lens and the radius of curvature of the test spherical surface are the same, and the imaging lens is configured to be movable on the optical axis. Further, for the same purpose, in the drawing of Patent Document 3, the position of the light source is shifted from the optical axis of the objective lens to the optical axis of the second lens (imaging lens) by the second mirror. The lens (imaging lens) is moved to an optically equivalent position on the optical axis of the objective lens. The solid and dotted lines in FIG. 8 are descriptions of the first embodiment of Document 3, and the broken lines are descriptions of the structure of claims of Document 3.

Of the light beam emitted from the objective lens L1 and forming the circular light source image c, a light beam having a certain illumination NA that illuminates one point e1 on the test spherical surface d1 is reflected at the point e1 and then the illumination light. This path is advanced to the objective lens L1, and the objective lens L1 becomes a parallel light beam, and a pupil h is formed at a position conjugate with the position of the light source. When the object side focal point of the imaging lens L2 coincides with this pupil, the imaging lens L2 creates a test spherical image e1 ′ at the image side focal point. Since this image fills the pupil, it is a bright and telecentric image with no decrease in the amount of peripheral light, and it is a good image that does not flow even when the focus is shifted. However, when the imaging lens L2 is moved to the position L2 ′, e1 ′ moves to e11 ′ indicated by the dotted optical path. Although the size of the image does not change, the telecentricity of the image is lost depending on the amount of movement of the imaging lens back and forth, and insufficient peripheral light amount and vignetting of the image also appear. Therefore, in order to obtain a telecentric image by this optical system, the position of the circular light source is moved by the imaging lens L2 according to the radius of curvature of the test spherical surface. The lens L2 must also move.
From the above description, it can be seen that it is not always necessary that the objective lens L1 and the imaging lens L2 have a telecentric configuration.
Further, as an advantage of the configuration of Example 1 of Patent Document 3, since the distance between the imaging lens L2 and the spherical image e1 ′ to be tested does not change, the imaging lens L2 and the camera can be integrated, and the focusing operation is not subject to testing. Sometimes it can be done just by moving the sphere.
Further, from the viewpoint of the size of the apparatus, since the position of the test sphere is fixed, it is not necessary to move the test sphere along the optical axis, and there is an advantage that a small apparatus can be made.

In the inspection of a spherical surface having a small curvature radius and a large spherical angle, first, as described above, in the small curvature radius spherical surface, the NA of the reflected light beam from one point of the test spherical surface is obtained by dividing the radius of the light source image by the curvature radius of the test spherical surface. Therefore, the illumination NA becomes large, and as described above, the imaging performance (resolution, vignetting of the image, etc.) of the subject spherical surface is hindered. In a spherical surface with a large spherical angle, the light beam reflected from the entire surface of the test spherical surface (collective light beam of reflected light from a single point) increases as the spherical angle increases, and the objective lens cannot capture this light beam. generate. Also, the objective lens itself must be subjected to advanced aberration correction.
In addition, even if the radius of curvature of the test spherical surface is changed while the objective lens L1 and the imaging lens L2 are in a telecentric configuration, the condition for always obtaining a telecentric image is that the reflected light from the test spherical surface becomes telecentric. That is, as shown in the solid line diagram of FIG. 9 of the present application, the circular light source image c is projected onto approximately half the radius of curvature, that is, the focal point of the test spherical surface. At this time, a telecentric image can always be obtained without adjusting the distances between the objective lens L1, the imaging lens L2, and the camera and without moving the entire optical system. However, there is a problem that the field diameter becomes smaller at a ratio derived from the distance between the objective lens (projecting lens) and the test surface and the radius of curvature of the test sphere than when a circular light source is projected at the center of curvature. The broken line diagram in FIG. 9 is a ray diagram when a light source image is projected on the center of curvature of the test spherical surface.

The range of the radius of curvature that can be inspected in Example 1 of Patent Document 3 will be described with reference to FIG. In the configuration of Example 1 of Patent Document 3, since the test spherical surface is at the focal position of the objective lens, a circular light source image must be projected on the objective lens side of the test spherical surface in the concave test spherical test. However, since the projection optical system has only one objective lens, the objective lens cannot form a circular light source image within the focal length of the objective lens, that is, between the test spherical surface and the objective lens. Therefore, in the case of the concave test spherical surface inspection, the concave test spherical surface having a radius of curvature smaller than the focal length of the objective lens cannot be inspected. In the spherical surface inspection for irregularities outside this range, if the light source is moved before and after the focal position on the image side of the objective lens without interfering with the half mirror, the light source image is moved to the object side (real image) and image side (virtual image) of the objective lens. The spherical surface can be inspected.
As described above, the concave and convex spherical surface having a small radius of curvature has a large illumination NA of a reflected light beam that illuminates one point of the entire test spherical surface from the light source image, which hinders observation of the test spherical surface.

Next, the second embodiment will be described with reference to FIG. In order to make FIG. 10 easier to understand, the positions of the light source and the imaging lens are changed to positions equivalent to those in FIG. In the configuration of the second embodiment, since the afocal light beam from the light projecting lens L3 forms a circular light source image c at the focal point of the objective lens L1, the center of curvature of the test spherical surface d1 is formed on the circular light source image c. Match. Since the test spherical surface is not in the focal position, the light that illuminates the test spherical surface from the circular light source image is reflected by the test spherical surface, follows the same path as the incident light, passes again through the object side focal point of the objective lens L1, and is reflected by the objective lens L1. Regardless of the radius of curvature of the subject spherical surface, a telecentric primary image e1 ′ having the same diameter is formed as a real image or a virtual image. The imaging lens L2 cannot obtain an image of the test spherical surface unless the secondary real image e1 ″ of the primary image e1 ′ is formed on the image sensor. The most preferable condition for forming the secondary image e1 ″ as a real image is the most preferable condition. The focus position of the imaging lens L2 that can move on the optical axis matches the primary image. The image formed at this time is not a telecentric image, but the distance between the imaging lens L2 and the secondary image e1 ″ can be fixed, and a secondary image can be obtained by moving the imaging lens L2 and the camera together.
When the distance between the objective lens L1 and the imaging lens L2 is fixed, including the case where the objective lens L1 and the imaging lens L2 are telecentric, for example, the objective lens L1 and the imaging lens L2 are fixed in the arrangement shown in FIG. In addition, when inspecting the concave test spherical surface d2 smaller than the radius of curvature of the test spherical surface d1, the primary image e2 ′ can be formed between the object side focal point of the imaging lens L2 and the imaging lens L2, as indicated by a broken line. However, at this time, the imaging lens L2 cannot make a real image on the camera side. Therefore, there is a range where the concave test spherical surface cannot be inspected depending on the radius of curvature.
This phenomenon also occurs when the objective lens and the imaging lens have a telecentric configuration. In the first place, the optical effect when the objective lens L1 and the imaging lens L2 have a telecentric configuration is that the objective lens L1 converts the telecentric light beam from the test object into a parallel light beam and forms a pupil at the focal position thereof. Is exhibited when this light beam is imaged as a telecentric image. Although the effect is obtained in the first embodiment close thereto, the form of the light beam is completely different in the second embodiment, so that the image is formed with the objective lens L1. Even if the lens L2 has a telecentric configuration, there is no optical effect.

  The range of the radius of curvature that can be inspected in Example 2 of Patent Document 3 will be described. In the configuration of Example 2 of Patent Document 3, the position where the circular light source image can be formed is fixed at the focal position of the objective lens because the light beam incident on the objective lens is afocal. Since the test sphere is placed with the center of curvature matched to the circular light source, if the test sphere is concave, it is placed away from the objective lens by the radius of curvature from the circular light source, and the convex test sphere is It is placed on the objective lens side by the radius of curvature. In this case, the primary image of the concave test spherical surface can be formed between the object side focal point of the imaging lens and the imaging lens in a wide range of curvature radii. Since the object lens is far away from the objective lens, the inspection surface cannot be inspected. In the case of a convex aspherical surface, the objective lens and the subject spherical surface interfere with each other, so that the radius of curvature that can be inspected is within the distance between the circular light source and the objective lens, that is, approximately within the focal length of the objective lens. In addition, the inspection with a small radius of curvature has the same inconveniences as the first embodiment in terms of both unevenness.

  The image formation with the structure of the claims of Patent Document 3 will be described with reference to the broken line diagram of FIG. The circular light source a is moved to an arbitrary position different from the focal position by the objective lens L1 (for the sake of clarity, the drawing of the first embodiment is used to position the objective lenses L1 to 2R (where R is the radius of curvature of the test spherical surface)). A circular light source image c is created, and the center of curvature of the concave test spherical surface d2 is matched with the circular light source image, and when the distance between the light source image and the test spherical surface is approximately R (= f), the objective lens L1 creates a primary image e2 ′ of the test spherical surface with a size derived from the radius of curvature of the test spherical surface d2 between the focal point of the objective lens L1 and the imaging lens L2. When the secondary image e2 ″ is created by focusing the imaging lens L2, the secondary image creates an image of the non-telecentric test sphere having a different image size each time the radius of curvature of the test sphere d2 changes. Also, objective lens and imaging lens Fixing Example 2 Like the radius of curvature in a range that can not image the possible primary image on the object side focal the length of the imaging lens of Patent Document 3 occurs.

The range of the radius of curvature that can be inspected with the configuration of the claims of Patent Document 3 will be described. In this configuration, since the circular light source image can be projected at an arbitrary position, the range of the radius of curvature that can be inspected on both the concave and convex surfaces is wide from simple optical calculation.
However, the position and magnification of the primary image change greatly each time due to the change in the radius of curvature of the test sphere, making it impossible to focus due to the movement of the imaging lens, and the image becomes too large or too small to be inspected. End up.
Further, when the distance between the objective lens and the imaging lens is fixed, the same phenomenon as described in the second embodiment of Patent Document 3 occurs.
Since Patent Document 3 also has a defect with respect to a small curvature radius, it seems that the curvature radius to be inspected for both the concave and convex spherical surfaces is set to an appropriate range in actual use.

In Patent Document 2, the optical configuration is configured to observe the test spherical surface by matching the center of curvature of the test spherical surface with the light source image that can be the focal position of the objective lens. Patent Document 2 is a simplified type of the configuration of Embodiment 2 of Patent Document 3, and an aperture of an appropriate size is provided at the focal position of the imaging lens to increase the NA on the imaging side to increase the sharpness of the aperture image, and The imaging device is moved to image the test spherical surface. This optical configuration is used when, for example, imaging the observation field diameter of a surface to be used used in a Fizeau interferometer using a point light source laser, and is not used in an apparatus that places importance on resolving power. Therefore, the resolution is insufficient for use as an appearance inspection machine for garbage scratches and the like.
In addition, since the basic optical configuration is the same as that of Embodiment 2 of Document 3, there are similar inconveniences such as whether an image can be formed or not a telecentric image. In addition, a point light source image can be projected onto a spherical surface with a small radius of curvature, but because it is a point light source, the image that can be imaged on all observable spherical surfaces has low resolution even if it has high contrast. There was insufficient resolution as a spherical appearance inspection machine.

  The problem common to Patent Documents 2 and 3 is that the illumination NA cannot be observed due to vignetting or lack of image sharpness in the inspection of a small radius of curvature depending on whether the illumination NA is too large or too small. And the like, a defect having a radius of curvature in which an image cannot be obtained due to an optical configuration, a problem in which the size and image formation position of the obtained image are changed, and a problem in image quality such that the image is not telecentric. In addition, a system capable of observing transmitted illumination cannot be constructed by simply changing the inspection optical system.

JP 2010-156558 A JP 2011-107092 A JP-A-56-157841

  In view of the above-described conventional drawbacks, the present invention provides a wide field of view and high accuracy for a whole or part of a test surface having a test surface including a spherical surface or an aspheric surface on at least a part of the surface. An epi-illumination or transmission illumination spherical inspection device that inspects a test member having a large cone angle for viewing the outer diameter of the test surface from the center of the test surface curvature with a wide radius range of the test surface that can be visually inspected and observed. The purpose is to provide.

In order to solve the above-mentioned problem, the invention according to claim 1 is an epi-illumination spherical surface inspection device for a test member having a test surface including a spherical surface or an aspherical surface on at least a part of a surface thereof.
An objective lens group having different focal lengths or numerical apertures for creating a primary image of the test surface as a telecentric real image or virtual image of approximately 1 time;
An objective lens supporting base on which a first objective lens selected from the objective lens group is attached so as to be detachably interchangeable with other objective lenses;
A test member placement moving table for mounting the test member and moving the test member along an optical axis of the objective lens, that is, an inspection optical axis;
An image relay lens and an imaging lens that are substantially telecentric on the object side, i.e., the primary image side and the secondary imaging side, by relaying a primary image created by the first objective lens; An image observation unit that moves along the inspection optical axis, and a monitor that displays a signal from the image sensor as an image. When,
An optical axis orthogonal to the inspection optical axis, which can be formed by disposing a light splitting deflection mirror between the first objective lens and the image relay lens or between the image relay lens and the imaging lens, A circular light source disposed on the light projecting axis, a first light projecting lens unit, and the light splitting deflecting mirror; and a light beam formed by the first light projecting lens unit via the light splitting deflecting mirror. A first incident light projecting unit that sends a circular light source image to a focal position of the first objective lens and illuminates the size of the circular light source or the member to be examined. The numerical aperture, that is, the illumination NA is variable.

  According to a second aspect of the present invention, in the epi-illumination spherical surface inspection apparatus according to the first aspect, when the first epi-illumination projection unit is located between the image relay lens and the objective lens, the first epi-illumination projection is performed. The first light projecting lens unit of the light unit includes a second light projecting lens unit including a collimating lens focused on the circular light source, and the afocal lens formed by the second light projecting lens unit. The light beam is sent to the first objective lens through a light splitting deflection mirror.

  According to a third aspect of the present invention, in the epi-illumination spherical surface inspection apparatus according to the first aspect, when the first epi-illumination projection unit is located between the image relay lens and the imaging lens, the first epi-illumination unit is provided. The first light projecting lens unit of the light projecting unit is a third light projecting lens unit having the collimating lens focused on the circular light source and a light projecting lens for creating a circular light source image. The circular light source image formed by the projection lens unit is projected to a position conjugate with the focal point of the image relay lens, and an afocal light beam is transmitted through the light splitting deflection mirror and the image relay lens to the first objective lens. It is characterized by sending to.

  According to these inventions, the epi-spherical surface inspection apparatus includes a small circular surface light source, and places the test surface so that the center of curvature of the test surface coincides with the center of the circular light source image formed by the objective lens at the object side focal point. The entire inspection area of the inspection surface is illuminated with a small illumination NA. At this time, since the test surface is selected so as to have a radius of curvature substantially equal to the focal length of the objective lens, when the test surface is a concave surface, the reflected light from the test surface passes along the same path as the illumination light. The lens passes through the lens, and a primary real image of about 1 time is made telecentric at a position of about twice the image side focal length of the objective lens. If the test surface is a convex surface, a primary virtual image of about 1 time is similarly made telecentric at the image side principal point position of the objective lens.

Therefore, an image with a deep depth of field can be obtained by observing the primary image using a telecentric imaging optical system on the object side, even if there are at least images that are telecentricly imaged. If a telecentric imaging optical system is used on both sides of the image side, it will not move so that the defect image will flow even if the focus with a deeper depth of focus is deviated from the defect. A good spherical image having a higher contrast than the inspection method can be observed as a substantially flat surface. In particular, it is suitable for inspection of a spherical surface having a small curvature radius and a large spherical angle.
Here, the first light projecting lens unit is defined as including a second light projecting lens unit, a third light projecting lens unit, and other types of light projecting lens units.

  According to a fourth aspect of the present invention, in the epi-illumination spherical surface inspection device according to any one of the first to third aspects, the size of the circular light source is determined from the circular light source image formed by the first objective lens. The illumination NA for illuminating the surface to be examined is in the range of 0.005 to 0.05.

  According to the present invention, since the illumination NA illuminates points on the entire test surface with a small illumination NA in the range of 0.005 to 0.05, it is suitable for the purpose of an apparatus having a deep depth of focus, good contrast and resolution. You can make a statue.

  According to a fifth aspect of the present invention, in the epi-illumination spherical surface inspection device according to any one of the first to fourth aspects, an imaging position of the circular light source formed by each of the objective lenses included in the objective lens group That is, the focal position of the objective lens is substantially the same position.

  According to the present invention, when the test surface of the test member is placed on the test member support base with the objective lens facing the objective lens, no matter which lens is selected from the objective lens group, the test subject is positioned substantially at the focal position of the objective lens. You can set the inspection. Therefore, it becomes easy to match the test surface with the focal position of the objective lens.

  According to a sixth aspect of the present invention, in the epi-illumination spherical surface inspection apparatus according to any one of the first to fourth aspects, a primary image of the test surface created by each of the objective lenses included in the objective lens group. The position is substantially the same position.

  According to the present invention, the primary image of the image relay lens can be easily focused regardless of which objective lens is selected from the objective lens group.

  According to a seventh aspect of the present invention, in the epi-illumination spherical surface inspection apparatus according to any one of the first to fourth aspects, the objective lens support base can be attached to and detached from the inspection optical axis.

  According to the present invention, when the objective lens is unnecessary, the objective lens support base can be removed, and when the objective lens support base is necessary, it can be attached.

The invention according to claim 8 is the epi-illumination spherical surface inspection device according to claim 7, wherein the second epi-illumination projection unit is replaceable with the first epi-illumination projection unit,
Including the circular light source, the second light projection lens unit, the light splitting deflection mirror, and a second objective lens;
When the second incident light projection unit is provided between the image relay lens and the test member,
In the second incident light projection unit, the circular light source, the second light projection lens unit, and the light splitting deflection mirror are coaxially attached to an objective plate, and the second objective lens is the inspection optical axis. It is characterized by being mounted on the same axis.

  According to a ninth aspect of the present invention, in the epi-illumination spherical surface inspection device according to the eighth aspect, the second epi-illumination projection unit is attached to a uniaxial stage movable along the projection axis and the inspection optical axis. It is characterized by being able to be inserted / removed substantially in line with

  According to these inventions, the second incident light projection unit uses the objective lens because the circular light source, the second projection lens unit, the light splitting mirror, and the objective lens are fixed and integrated with the objective plate. When inspecting a spherical surface with a small curvature radius and a high spherical angle, the second incident light projection unit is inserted so as to substantially match the inspection optical axis, and during the transmitted illumination inspection, the second incident light projection unit is detached from the inspection optical axis. Is done. Therefore, it is possible to switch between the epi-illumination inspection and the transmission inspection only by the operation of moving the single axis stage.

The invention according to claim 10 is the epi-illumination spherical surface inspection device according to claim 7,
The third incident light projection unit can be replaced with the first incident light projection unit,
When the third incident light projection unit is provided between the image relay lens and the test member,
The third incident light projection unit includes the circular light source disposed on the light projection axis,
An exchange projection lens selected from a group of exchange projection lenses having different numerical apertures or focal lengths, which are arranged in an afocal light beam produced by a collimator lens and a collimator lens substantially in focus with the circular light source. And a fourth projector lens unit having
In the third epi-illumination projection unit, the circular light source and the fourth projection lens unit pair having a guide that can move on the projection axis and the light splitting deflection mirror are coaxially objective. Mounted on the board,
In the third incident light projection unit, the pair of the circular light source and the fourth light projection lens unit moves on the light projection axis with respect to the light splitting deflection mirror along the guide portion of the moving guide, and is exchanged. The circular light source image formed by the light projecting lens is sent to the inspection optical axis through the light splitting deflection mirror, and the circular light source image is moved on the inspection optical axis.

  According to an eleventh aspect of the present invention, in the epi-illumination spherical surface inspection device according to the tenth aspect, the third epi-illumination projection unit is attached to a uniaxial stage movable along the projection axis, and the inspection light It is characterized by being able to be inserted / removed substantially in line with the shaft.

  According to these inventions, since the third epi-illumination projection unit is fixed to and integrated with the objective plate, switching between inspection of a spherical surface having a large curvature radius and a small spherical angle without using an objective lens and transmitted illumination inspection is performed. The third incident light projection unit is inserted so as to substantially coincide with the inspection optical axis, and the third incident light projection unit is detached from the inspection optical axis at the time of transmitted illumination inspection. Therefore, it is possible to switch between the epi-illumination inspection and the transmission inspection only by the operation of moving the single axis stage.

  In addition, according to these inventions, since the projection optical system is an independent optical system that does not use an imaging lens such as an objective lens or an image relay lens when projecting the circular light source onto the test surface, the circular light source Can be projected to any position on the inspection axis, so that the defect of Example 1 of Patent Document 3, that is, the concave spherical surface cannot be inspected when the radius of curvature is shorter than the focal length of the objective lens. Etc. can be eliminated.

  Further, according to these inventions, since the field diameter of the test surface is determined by the viewing angle, the aperture angle (viewing angle) of the light beam that forms a circular light source image from the light projecting lens with which the light projecting unit illuminates the test surface is The light source image is projected to a predetermined position on the surface to be examined while keeping it as large as possible and keeping a large aperture angle. At this time, in order to project the light source image at a predetermined position without changing the aperture angle of the light beam, it is sufficient that the circular light source and the whole light projecting unit can be moved as they are.

Further, according to these aspects of the invention, the center of curvature of the test surface at incident illumination inspection of the test surface of the small to medium spherical angle medium to large radius of curvature, or a position of substantially 1/2 of the radius of curvature, That is, it is useful when a circular light source image is projected on the focal position of the surface to be examined and when the transmitted illumination spherical inspection is switched.

  The invention according to claim 12 is the epi-illumination spherical surface inspection apparatus according to any one of claims 1 to 11, wherein the image observation unit includes a zoom optical system between the image relay lens and the imaging lens. The image relay lens is detachable from an image relay lens having a different focal length or numerical aperture, or the imaging lens is detachable from an imaging lens having a different focal length or numerical aperture.

  According to the present invention, inspection can be performed from a small outer diameter to a large test surface. The image relay lens used in claim 1 is a low-magnification lens of 0.5 to 2 times because the range of the observable lens diameter is widened and the numerical aperture may be small. Therefore, an enlarged image can be displayed on the image sensor for inspection of a small-diameter test surface, and a reduced image can be displayed for inspection of a large-diameter test surface.

  According to a thirteenth aspect of the present invention, in the transmitted epi-illumination spherical surface inspection device including the epi-illumination spherical surface inspection device according to any one of the first to twelfth aspects, the first to third members are sandwiched by the test member. Any one of the first to third incident light projection units is arranged on the opposite side of any one of the incident light projection units, and includes a transmission light projection lens. It is a transmission epi-illumination spherical inspection device capable of selectively performing illumination spherical inspection and epi-illumination spherical inspection.

  According to this invention, in the epi-illumination spherical surface inspection apparatus using the first epi-illumination projection unit, the objective lens support is removed, and the transmission light projection unit is disposed on the opposite side to the test member placement position of the epi-illumination spherical inspection apparatus. By attaching it, the transmitted illumination inspection of the transmission object can be performed.

  Further, in the epi-illumination spherical surface inspection apparatus using the second and third epi-illumination projection units, the transmission light projection unit is attached to the opposite side of the test member mounting position of the epi-illumination spherical inspection apparatus on the test member mounting moving table. Thus, the transmitted illumination inspection of the transmitted object to be inspected becomes possible.

According to the present invention, a surface to be measured having a small curvature radius and a large spherical angle is inspected by using the structure of claims 1 to 9 as appropriate in the incident surface inspection of a spherical surface, and the surface to be measured has a large curvature radius and a small spherical angle. Are inspected using the configuration of claim 10 and claim 11 in which no objective lens is used. The transmission inspection of the test surface is performed using the structure of claim 13.
A twelfth aspect of the present invention commonly used for the epi-illumination inspection and the transmission illumination inspection relates to the magnification of the imaging optical system and the size of the image sensor used.

  In the transmitted illumination inspection, the apparatus described in Patent Document 1 is used. From the contents described in Document 1, a spherical inspection with a large radius of curvature and a small radius of curvature is possible. For the spherical surface with a large curvature radius of the epi-illumination, use Example 1 described in Patent Document 3 as it is, or set the test surface installation position as the focus position of the objective lens, and set the projection position of the circular light source as the focus position of the test spherical surface. Change to (1/2 of the radius of curvature). When a circular light source is projected at the focal position, the inspection principle is the same as that in which the light source image is projected at the focal point of the lens to be tested in the transmission illumination inspection of Patent Document 1.

  The present invention provides a technique suitable for inspection of a spherical surface having a small curvature radius and a large spherical angle, and can easily incorporate the prior art of the past, and widens the inspection range of various shapes of the inspection surface. is there.

  More specifically, it enables the epi-illumination inspection of a spherical surface with a small curvature radius and a large spherical angle, and also makes a spherical or aspherical epi-illumination with various shapes, that is, combinations of outer diameter, curvature radius, spherical angle, etc. The inspection range is greatly expanded compared to the prior art. In addition, it can be combined with an inspection device for transmitted illumination, so that almost all lenses and lens molds can be inspected. Furthermore, it was confirmed by experiments that an aspheric lens is possible if the asphericity is small.

  The meaning of creating a telecentric image is a device for displaying a spherical surface as if it were a planar image, and obtaining an image that does not change its size even when the focus is high and the depth of focus is high. Therefore, defects on the polished surface with almost no defects are displayed with high contrast, and the defects can be measured. In addition, the telecentric image created by this device is determined by selecting a single objective, so the viewing angle is determined. Therefore, the size of the image on the surface to be inspected remains constant even when the radius of curvature is different, and is suitable for imaging with a CCD or the like. It is.

  In addition, the entire spherical surface having a large spherical angle, which could not be conventionally achieved, can be easily expressed as a substantially planar image in one image, and the image quality is high, and defects on the spherical surface of 5 μm or less can be detected. Further, the apparatus of the present invention has good operability with a simple configuration without using particularly precise parts and products, and the time required for inspection can be shortened.

1 is a schematic diagram showing a schematic overall configuration of an epi-illumination spherical surface inspection apparatus according to a first embodiment of the present invention. It is typical sectional drawing of the circular light source device of the epi-illumination apparatus concerning the 1st Embodiment of this invention. It is a schematic diagram which shows this schematic structure when the epi-illumination apparatus concerning the 1st Embodiment of this invention changes a position and is arrange | positioned in an image observation unit. It is a figure regarding the spherical angle used by this invention, a viewing angle, and illumination NA. It is an optical conceptual diagram regarding the illumination method and image formation concerning the 1st Embodiment of this invention. It is a schematic diagram which shows the schematic whole structure of the epi-illumination transmission illumination spherical surface inspection apparatus concerning the 2nd Embodiment of this invention. The right side of the optical axis is a transmission illumination optical configuration diagram during epi-illumination and the left is during transmission illumination. It is an optical path diagram of a position of a test surface concerning the 3rd embodiment of the present invention, reflected light from a test surface, and transmitted light. The right side of the optical axis is a transmission illumination optical configuration diagram during epi-illumination and the left is during transmission illumination. It is an optical conceptual diagram concerning patent document 3. FIG. It is an optical conceptual diagram concerning patent document 3. FIG. It is an optical conceptual diagram concerning patent document 3. FIG. It is a schematic diagram of the optical system of 1st Example of this application.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Even if the embodiments are different in all the drawings, the same or corresponding members are denoted by the same reference numerals, and common description is omitted. Further, the first incident light projection unit using the second light projection lens unit is the first incident light projection unit A, and the first incident light projection unit using the third light projection lens unit is the first incident light projection unit. The optical unit B will be described. However, the first light projecting lens unit is not limited to the second and third light projecting lens units.

FIG. 1 is an overall view showing a schematic configuration of an epi-illumination spherical surface inspection apparatus 90 according to the first embodiment of the present invention. The curvature radius is about 1 to 30 mm, and the spherical angle shown in FIG. This configuration is suitable for the inspection of the surface 1b to be measured. FIG. 1 is a diagram in which the first incident light projection unit A90d is disposed between the image observation unit 90c and the objective lens support 90b.
The first vertical illuminator unit A90d includes a circular light source 9 of the circular light source device 11 shown in FIG. 2, a second light projecting lens unit 91aa comprising collimating lens 8a focused in a circular light source 9, the light splitting deflection The afocal beam formed by the collimator lens 8 a is sent to the objective lens 3 through the light splitting deflection mirror 7. In the description of the present embodiment, the inspection of the concave test surface 1b will be mainly described as an example.

  Each objective lens 3 selected from the objective lens group 90e of the present embodiment creates a circular light source image 3a of the small circular light source 9 of the circular light source device 11 at the object side focal position 3b. The objective lens 3 is selected to have a focal length close to the radius of curvature of the test surface 1b of the test member 1, and the test member 1 is arranged so that the center of curvature 1a of the concave test surface 1b and the circular light source image 3a coincide. Is done. Therefore, the test surface 1b is at a position approximately twice the object-side focal length of the objective lens 3. When the test surface 1b is illuminated with illumination light from the circular light source image 3a in this arrangement, the concave test surface primary image 3c is formed as a real image that is approximately one time at a position that is approximately twice the focal length on the image side. Further, when a convex test surface is placed at the objective lens object-side principal point 3h, a primary virtual image of the convex test surface that is approximately 1 time is created at the image-side principal point 3i.

  The objective lens must be corrected in order to produce a clear image under these conditions, but it is experimental, but is applicable to an infinitely corrected objective lens for microscopes, that is, a long working distance objective lens for epi-illumination observation. To do. The microscope objective lens group is generally lined up at 100 times, 50 times, 20 times, and 10 times, and the focal length and the numerical aperture (NA) are set in a series according to the magnification, which is suitable for this apparatus.

  In the experiment, the radius of curvature of the surface 1b to be inspected of these objective lenses is preferably 0.5 to 1.5 times the focal length of the objective lens used, and the inspectable spherical angle (viewing angle) ) Is equivalent to the numerical aperture (NA) of the objective lens. Specifically, since the 100 × objective lens for a microscope has a focal length of 2 mm and NA of about 0.9, the inspectable surface 1b has a radius of curvature of 1 to 3 mm and a viewing angle ≦ 65 degrees. (NA = 0.9), similarly, with a 50 × lens, the radius of curvature is 2-6 mm and the viewing angle ≦ 45 degrees (NA = 0.7), and with a 20 × lens, the radius of curvature is 5-15 mm and the viewing angle ≦ 30 °. (NA = 0.5) A 10 × lens has a radius of curvature of 10 to 30 mm and a viewing angle ≦ 17 degrees (NA = 0.3), and a spherical surface in this range can be inspected.

  In the inspection of the convex test surface 1b, the objective lens object side principal point 3h is preferably within the WD of the objective lens, that is, within the working distance, and WD is preferably about 1.5 times the focal length of the objective lens. The lens 3 and the test surface 1b interfere with each other and the test surface 1b cannot be inspected.

  When observing the test surface 1b having a different radius of curvature using one objective lens, the primary image of the test surface 1b having the same viewing angle is the same diameter as the pupil diameter of the objective lens as shown in FIG. Make a statue of. That is, the image size does not change, but the image magnification and the image formation position are different.

  In addition, since each of the objective lenses 3 in the objective lens group 90e has the same focal position when inserted into the objective lens frame 3g of the objective lens support 90b, an adapter frame 3f is designed to set the primary image position. In order to obtain the same position, two types of adapter frames 3f for the concave test surface 1b and two for the convex test surface 1b are prepared for one objective lens. This is because, regardless of which objective lens in the objective group is selected from the viewpoint of operability, it is easy to find the surface of the test surface with the installation position of the test surface being the same position, and the primary image position is substantially the same as that of the image relay lens. The focus position can be set easily.

The test member placement moving base 90a of this embodiment places the test member 1 regardless of whether the test member 1 transmits or does not transmit light, and the optical axis of the test surface 1b is adjusted by a centering device (not shown). After being aligned with the inspection optical axis 20, it is moved up and down on the paper surface by a uniaxial moving stage (not shown) along the inspection optical axis. Since the position of the test surface 1b can be detected by matching the center 1c of the surface 1b of the test surface with the circular light source image 3a, the test is performed when the concave test surface 1b is moved away from the objective lens by the radius of curvature based on this position. The center of curvature 1a of the surface 1b can be matched with the circular light source image 3a. At this time, a secondary image 6a of the test surface 1b can be obtained on a monitor (not shown).
The position of the test surface 1b is detected by moving the image observation unit 90c, adjusting the focus position of the image relay lens 4 to approximately the vicinity of the image side focal point 3j of the objective lens, and moving the test surface 1b up and down with respect to the objective lens. The diameter of the bright circular portion on the monitor (not shown) changes. The time when the outer diameter of the circular portion becomes the largest is when the center of curvature of the circular light source image 3a coincides with the surface 1b to be examined.

  The objective lens support 90 b of this embodiment is an objective that can be mounted on and removed from the stage member 40 of the epi-illumination spherical surface inspection apparatus 90 and can be attached to and detached from the objective member 3 coaxially with the inspection optical axis 20. The objective lens mounting plate 3d to which the lens frame 3g is attached is included, and a microscope objective lens and other objective lenses attached to the adapter frame 3f are positioned on the inspection optical axis and dropped. The reason that the objective lens support can be attached and detached is that the objective lens and the objective lens support are not required when used for general microscopic inspection or when inspecting a spherical surface having a large radius of curvature, which will be described later, and in transmitted illumination inspection. .

  The image observation unit 90c of the present embodiment has an image relay lens 4 that captures and relays to the imaging lens 5 a primary image 3c to be detected that is telecentric by the objective lens 3, and a telecentric configuration on both sides of the image relay lens 4. It includes an image sensor 6 that captures a secondary image 6a of the substantially telecentric surface 1b that is formed by the imaging lens 5 that is disposed, and a display monitor (not shown) that displays a signal from the image sensor as an image. A signal from the image sensor is transferred to a computer or the like (not shown), and analysis and measurement such as defect extraction and defect classification are performed by an image processing device, a measurement device, or the like.

As the image relay lens, it is preferable to select a working distance WD and a lens having an infinity design with a large aperture.
In the following description, the image relay lens and the imaging lens will be described as lenses of infinity design.
The reason why the WD is large is that not only the space is secured and the workability is improved, but also the first incident light projection unit A90d is easily installed when it is disposed between the image relay lens 4 and the objective lens 3. It is. The reason for the large aperture is that the observation field of view of the telecentric lens is determined by the aperture, so that it corresponds to the observation of the test surface 1b having a large diameter. Further, since the image formation NA of the primary image is small, the NA (numerical aperture) of the image relay lens 4 may be small, and as a result, a low-magnification lens having a large aperture is suitable.

  The optical system of the image observation unit 90c has a large field of view, forms an image in a telecentric manner, and can obtain an image with a deep depth of focus and a good contrast. Further, since the optical system of the apparatus has a low magnification, a zoom lens 30 is provided between the image relay lens 4 and the imaging lens 5, and both the image relay lens 4 and the imaging lens 5 have different focal lengths and numerical apertures. It should be replaceable.

  The illumination light flux of the incident light projection unit will be described. The first incident light projection unit A90d of this embodiment is an incident light projection unit installed between the image relay lens 4 and the objective lens 3, and sends an afocal light beam toward the objective lens. As shown in FIG. 5, the light beam traveling in the same direction from the circular light source 9 is emitted from the collimating lens 8a and then intersects on the focal plane 8af of the collimating lens 8a to illuminate the focal plane with so-called telecentric illumination. When the focal plane is matched with the primary image plane 3c formed by the objective lens 3, the light emitted from one point on the focal plane forms a pupil (circular light source image 3a) at the focal point of the objective lens through the objective lens 3, and then the test object One point on the surface of the surface 1b is illuminated and reflected. The light reflected by the surface 1b to be examined follows the same path as the forward path and returns to the exit point of the focal plane. This optical path diagram means that if the aberration of the objective lens 3 is corrected, a spherical surface is created as a planar image. When the test surface 1b is a convex surface, the test surface 1b placed at the objective lens object side principal point 3h creates a virtual image at the objective lens image side principal point 3i, so that the focal plane of the collimating lens 8a is the objective lens image. What is necessary is just to make it correspond to the side principal point 3i. That is, it is established if the focal plane of the image relay lens coincides with the primary image plane formed by the objective lens 3.

  In the above description, the best illumination conditions are described. In an actual apparatus, the effect does not drop even if the matching accuracy between the focal plane of the collimating lens 8a and the primary image position is low. Since the circular light source image 3a created by the objective lens 3 does not impair the form of the circular light source even if the above adjustment is not performed, the point on the entire surface 1b of the test surface 1b is illuminated from the circular light source image 3a. Think about it.

When the light splitting deflection mirror 7 is between the image relay lens 4 and the imaging lens 5, the first incident light projection unit B90f has a circular shape of the circular light source device 11 as shown in FIGS. 3 and 91ab. The collimating lens 8a focused on the opening 9b and the light projecting lens 8b are included, and the circular light source image formed by the light projecting lens 8b is matched with the position 8c conjugate with the image side focal position of the image relay lens 4. Therefore, an afocal light beam is emitted from the image relay lens 4 toward the objective lens 3 through the light splitting deflection mirror 7.
It should be noted that the thickness of the light splitting deflection mirror 7 is set so that the incident light projection unit is located between the image relay lens 4 and the objective lens 3 in FIG. 1 or the image relay lens 4 in FIG. If it is between the test member 1, it is preferably 0.3 mm or less.

Next, the spherical angle, viewing angle, and illumination NA will be described with reference to FIG. The numerical aperture (NA) that forms the circular light source image 3a of each lens of the objective lens group is equal to the aperture angle that illuminates the entire surface 1b of the apparatus, and the outer diameter of the surface 1b that can be inspected and the surface to be inspected. Although it is 1/2 of the cone angle with the center of curvature of the surface 1b as the apex, it is referred to as a viewing angle in the present application. A larger viewing angle can be observed as the NA of the objective lens 3 is larger, so an objective lens having a larger NA is suitable for this apparatus. Moreover, 1/2 of the cone angle formed by the outer diameter of the surface 1b to be measured and the center of curvature is referred to as a spherical angle. Further, ½ of the cone angle that illuminates one point on the surface 1b to be examined from the circular light source image 3a is referred to as illumination NA. The illumination NA is such that the diameter of the circular light source image is φd, and the radius of curvature of the test surface 1b is r.
Illumination NA = d / (2r)
Calculated by An appropriate value of the illumination NA is experimental, but 0.005 to 0.05 is preferable.
The diameter φd of the circular light source image created by the objective lens is
φd = diameter of circular light source × (focal length of objective lens / focal length of collimating lens)
Calculated by
The illumination NA may be changed by exchanging the aperture plates 9a having different aperture diameters 9b of the circular light source 11 shown in FIG. The light source is preferably an LED that emits visible light.

Next, the difference between the optical system of the first example of the present application and the optical system of Example 2 of Patent Document 3 will be described. FIG. 11 shows a schematic diagram of the optical system of the first embodiment of the present application. Compared with FIG. 10 showing Example 2 of Patent Document 3, in the configuration of FIG. 11 of the first example of the present application, an image relay lens L4 which is a convex lens is added between the objective lens L1 and the imaging lens L2, and the image relay is performed. While the lens L4 and the imaging lens L2 have a telecentric relationship, the telecentric primary image created by the objective lens L1 is relayed by the image relay lens L4, and the imaging lens L2 creates a telecentric secondary image, whereas FIG. With this configuration, you cannot make a telecentric image.
In FIG. 11, a high-contrast image in which the image size does not change and the image does not flow can be obtained even if the focus is not strict, and has an optimum focal length according to the radius of curvature of the test surface 1b. An objective lens group 90e is prepared and consideration is given so as not to place an optical burden on each objective lens.

  The configuration and the inspection principle of the first embodiment have been described above. In the present invention, the other two units are independent on the basis of any one of the test surface 1b, the objective lens 3, and the image relay lens 4. Thus, it is sufficient to move along the inspection optical axis. For example, three types of configurations are possible as long as the objective lens 3 and the image observation unit 90c can move relative to each other with respect to the test surface 1b, and these are also included in the present invention.

  In addition, in this embodiment, it is stated that it is suitable for inspection of a spherical surface having a small curvature radius and a large spherical angle. If the curvature radius is increased, the entire apparatus becomes too large and a suitable objective lens cannot be obtained. For this reason, even if the test surface 1b has a large radius of curvature, the same effect can be obtained by using an optical system corresponding to the large radius of curvature, so the present invention has no limitation on the radius of curvature.

A second embodiment will be described. FIG. 6 shows an epi-illumination inspection apparatus 91 according to the second embodiment of the present invention. Similar to the first example, the epi-illumination inspection and the visible light transmission inspection of the test surface 1b having a small curvature radius and a large spherical angle. It is an inspection device that can perform a transmission illumination inspection of a member by switching.
The change from the first embodiment is that the uniaxial stage 41 instead of the objective lens support 90b is attached, and the first incident light projecting unit A 90d or the first incident light projecting unit B 90f to the second incident light projecting unit 91d. In addition, a centering device 91b and a transmission light projecting unit 91f for the test surface 1b are newly attached.
The objective plate 43 is fixed to the uniaxial stage 41 via the spacer 47, and the second incident light projection unit 91d is connected to the inspection optical axis 20 at a position where the optical axis of the light splitting deflection mirror 7 substantially matches the transmitted illumination. The deflection mirror housing 42 can be moved and positioned to a position that does not block the transmission inspection light beam during transmission inspection during observation.

The second incident light projection unit 91d includes a circular light source device 11 disposed in the light projection axis 21, a collimator lens 8a (91aa) having a focal position on the circular light source 9 of the circular light source device 11, and light splitting deflection. It comprises a deflection mirror housing 42 that houses the mirror 7, an objective lens 3, and an objective plate 43 to which the objective lens 3 is attached. The deflection mirror housing 42 is placed and fixed on the objective plate 43 such that the optical axis of the light splitting deflection mirror 7 coincides with the objective lens mounting portion of the objective plate 43, for example, an axis such as a screw or a fitting portion.
The light from the circular light source 9 becomes an afocal light beam by the collimating lens 8a, is incident on the objective lens 3 through the light splitting deflection mirror 7, and forms the circular light source image 3a at the focal point 3b of the objective lens 3 while the test surface 1b. Illuminate. The reflected light from the test surface 1b follows the same optical path as that at the time of incidence and passes through the objective lens 3 to form a primary image 3c that is approximately one time the test surface 1b. When the primary image is focused on the image relay lens 4 of the image observation unit 90c, a secondary image of the test surface 1b is displayed on a monitor (not shown).

Next, a case where the transmitted illumination inspection is performed by the epi-illuminated transmitted illumination spherical surface inspection device 91 according to the second embodiment shown in FIG. 6 will be described, but an outline of the transmitted illumination will be described prior to that.
The transmission light projection unit 91f used for the transmission illumination inspection has the same basic configuration as the incident light inspection apparatus 91d in the first embodiment of the present application, and has a circular light source having a small circular light source 9 at the focal position of the transmission collimator lens 8d. The apparatus 11 is attached, and the light from the circular light source 9 becomes an afocal light beam and is bent by the deflection mirror 49 so as to coincide with the inspection optical axis 20. After that, the afocal light beam is circular light source image 8g at the focal position of the transmissive projection lens 44 selected from the transmissive projection lens group 92e shown in FIG. 7 compatible with the epi-illumination objective lens group 90e having a different focal length or numerical aperture. make. The circular light source image 8g is adjusted to the focal point 92g of the transmission target member 12 that is an optical lens, for example, by the epi-subject test member placement moving base 91c having the uniaxial stage 53. The telecentric light beam emitted from the transmission test member 12 is focused on the test surface 1b of the transmission test member by focusing the image observation unit 90c on the imaging element, so that the front or back test surface of the transmission test member 12 is placed on the imaging device. Form an image.

  When the transmitted illumination inspection is performed by the reflected light transmitted illumination spherical surface inspection apparatus 91 according to the second embodiment, the second incident light projection unit 91 d fixed to the uniaxial stage 41 is moved by the light dividing deflection mirror with the rotary knob 46 of the uniaxial stage 41. Is moved to a position where the transmitted inspection light beam emitted from the transmission inspection member 12 is not blocked from a position where the optical axis is substantially coincident with the inspection optical axis 20. Thereafter, the image observation unit 90c is brought close to the transmission test member 12 to focus on the test surface 1b of the transmission test member 12, and the circular light source image 8g formed by the transmission light projection lens is uniaxially formed at the focal point 92g of the test optical lens. Matching is performed using the rotary knob 54 of the stage 53. With this alone, the transmitted illumination inspection similar to the transmitted illumination inspection apparatus of Patent Document 1 can be performed. A part of the left side of the inspection optical axis in FIG. 6 is a schematic diagram of the transmitted illumination inspection.

FIG. 7 shows an epi-illumination illumination spherical surface inspection device 92 according to the third embodiment of the present invention. The epi-illumination inspection of the surface 1b to be inspected has a larger radius of curvature and a smaller spherical angle than the first and second examples. It is an inspection device that can perform the transmission illumination inspection. The changes from the second embodiment are the removal of the objective lens 3 and the spacer 47 and the replacement from the second incident light projection unit 91d to the third incident light projection unit 92b.
In addition, in FIG. 7, the Example by transmitted illumination is included in part. The right side of the optical axis is a transmission illumination optical configuration diagram during epi-illumination and the left is during transmission illumination.

A method of moving the light source image using the third incident light projection unit 92b on the inspection axis and switching to the transmitted illumination inspection will be described.
The circular light source is moved by connecting the circular light source device 11, the collimating lens 8a of the fourth light projecting lens unit 92a, and the replacement light projecting lens 8e together with an outer diameter portion that can move along the inner diameter of the moving guide 50 and the frame of each other. It is housed in a frame with a threaded part that can be integrated into a set with screws. A circular light source image 3a formed by the replacement light projecting lens 8e is obtained by inserting a pair of the circular light source and the fourth light projecting lens unit into the inner diameter of the moving guide 50 and moving it with respect to the light splitting deflection mirror. The light is projected onto the inspection optical axis 20 through the light splitting deflection mirror and moved. When the position of the circular light source is determined, the set of the circular light source and the fourth light projecting lens unit is fixed with the fixing screw a56a.
In the switching to the transmitted illumination inspection, since the objective plate 43 is fixed to the uniaxial stage 41, the third incident light projection unit 92b has a position where the optical axis of the light splitting deflection mirror 7 substantially coincides with the inspection optical axis 20. What is necessary is just to position and move by the rotary knob 46 to the position where a light division | segmentation deflection | deviation mirror housing | casing does not block a transmission inspection light beam at the time of transmission illumination observation.

  The epi-illumination inspection in the transmitted epi-illumination spherical surface inspection apparatus in the third embodiment will be described. The test member 1 is placed on the epi-illumination test member mounting table 39 shown in FIG. When the test member 1 is moved to the focus position of the image relay lens 4 of the image observation unit 90c that moves along the test optical axis 20 by causing the test surface 1b and the test optical axis 20 to substantially coincide with each other by the centering device 91b, The outer diameter end surface of the test member 1 is observed. Next, a piece of paper or the like is placed on the test surface 1b, and the set of the circular light source and the fourth light projection lens unit 92a is moved back and forth along the guide portion of the moving guide 50 with respect to the light splitting deflection mirror 7. A circular light source image 3a is created. If the test surface 1b is concave, the fourth light source image 3a is placed on the image relay lens 4 side in order to match the position of half the radius of curvature of the test surface, that is, the focal position of the test surface 1b. The optical lens unit 92a is moved. At this time, the circular light source image 3a and the focus of the test surface 1b coincide and the image of the test surface 1b appears on the monitor. If the test surface 1b is a convex surface, the circular light source image may be moved in the direction opposite to the concave surface.

An optical system according to the third embodiment will be described.
When a light source image is projected onto the focal point of the test surface 1b placed at the focus position of the image relay lens 4, the light that illuminates one point on the test surface is reflected parallel to the inspection optical axis 20 and enters the image observation unit 90c. An image is formed on the element 6. The configuration of Example 1 of Patent Document 3 is such that a test sphere is placed at the focal point of the objective lens and a circular light source image 3a is projected onto the center of curvature c2 of the test sphere as shown by the broken line in FIG. The invention includes the image relay lens 4 and the imaging lens 5 of the present invention because the reflected light becomes a telecentric light beam because the light source image is projected onto the focal position c1 of the test surface 1b as shown by the solid line in FIG. A telecentric optical system on both sides is suitable for this inspection method.
Further, this optical system illuminates the surface of the test lens by placing a circular surface light source image at the focus position of the test lens, which is the spherical transmitted illumination observation method described in Patent Document 1, and is emitted from the test lens surface. This is the same as the configuration in which a telecentric light beam is taken in and an image of the surface of the lens to be examined is formed with a telecentric lens on both sides. Therefore, the spherical transmission observation method described in Patent Document 1 can be used as it is as the transmission illumination inspection apparatus of the third embodiment of the present application.

  In this case, the curvature radius and field diameter of the surface to be examined will be described briefly. The visual field diameter of the convex test surface 1b is compared with the configuration of Example 1 in which a circular light source is projected onto the center of curvature (see FIG. 9), that is, when a circular light source image is projected onto the center of curvature of the test spherical surface. Although it is small, a large difference in visual field diameter does not occur in the case of the test surface 1b having a large curvature radius. This is because in the inspection of the test surface 1b having a large radius of curvature, the distance between the replacement light projecting lens 8e and the test surface is sufficiently shorter than the distance between the projected light source image and the test surface. This is because the diameter of the light beam that forms the circular light source image 3a from the lens 8e does not change significantly at the position of the test surface between the case of projecting at the center of curvature and the case of projecting to the focal point.

However, observation of a convex test surface having a radius of curvature of 30 to 100 mm has the following problems. In the case of the convex test surface 1b, the projection position of the circular light source image 3a is farther from the test surface 1b at the focus (focus) position of the image relay lens 4, so that the circular light source image 3a is focused on the test surface 1b. If the fourth light projection lens unit 92a is brought close to the inspection optical axis 20 in order to match the position, interference with the light splitting deflection mirror 7 occurs and the circular light source image cannot be projected on the center of curvature of the surface to be examined. If a lens having a long focal length is used as the interchangeable projection lens 8e, a circular light source image can be projected on the center of curvature of the lens to be examined. However, the viewing angle is reduced, resulting in a problem that the field of view is reduced.
To solve this problem, Example 1 of Patent Document 3 has a telecentric configuration of the objective lens and the imaging lens, places the test sphere at the focal position of the objective lens, and projects a circular light source at the center of curvature of the test sphere. Therefore, when the circular light source image is formed at the center of curvature c2 instead of the focal point c1 of the test spherical surface using Example 1 of Patent Document 3, the image formed by the image observation unit 90c is not telecentric, but the image is observed. Is possible.
As shown in FIG. 7, the third incident light projection unit 92b can slightly move the circular light source device 11 with respect to the collimating lens 8b by slightly shifting the adjustment frame 60 with the inner diameter of the light source frame 59 as a guide. It may be. In this case, the position of the circular light source image 3a created by the interchangeable projection lens 8e can be slightly shifted from the focal position of the interchangeable projection lens 8e. By this operation, the focal lengths of the individual lenses of the interchangeable lens group are intermittently selected, whereas the focal lengths are prepared continuously. However, the circular light source image 3a is a slightly blurred image and the viewing angle changes, but this is not a problem in practice.

  Next, description will be made with reference to FIG. 7 when switching to the transmitted illumination inspection by the epi-illuminated transmitted illumination spherical surface inspection device 92 according to the third embodiment. The third incident light projection unit 92b is not obstructed by the rotary knob 46 of the uniaxial stage 41 from the transmission inspection light beam emitted from the transmission inspection member 12 from a position where the optical axis of the light splitting deflection mirror 7 substantially coincides with the inspection optical axis 20. The third incident light projection unit 92b is moved to the position. With this alone, the same principle as the transmission illumination inspection apparatus of Patent Document 1, that is, the transmission illumination inspection that matches the circular light source image with the focal point of the member to be detected can be performed. A part of the left side of the inspection optical axis 20 in FIG. 7 is a schematic diagram of the transmitted illumination inspection.

The features and common specifications of the epi-illumination transmission illumination spherical inspection device 91 and the epi-illumination transmission illumination spherical inspection device 92 will be described.
FIG. 6 relates to a second embodiment of the present invention, and is an epi-illumination transmission illumination spherical surface inspection device 91 for the surface 1b to be measured having a small radius of curvature and a large spherical angle as in the first embodiment of the present invention. The second epi-illumination projection unit 91d is used in the optical device, and FIG. 7 relates to the third embodiment of the present invention. A large curvature radius small spherical angle using the third epi-illumination projection unit 92b of the present invention. The epi-illumination and transmission illumination spherical surface inspection device 92 for the surface 1b to be measured includes both a transmission / projection unit 91f and a centering device 91b shown in FIG.

  The configuration of the epi-illumination inspection will be described. The second incident light projection unit 91d uses the objective lens 3, but the third incident light projection unit 92b does not use the objective lens. The two incident light projection units are fixed to the objective plate 43 having the same shape and can be exchanged. Switching between the two epi-illumination projection units uses the spacer 47 in the second epi-illumination projection unit that uses the objective lens 3 because the mounting position of the member 1 to be tested is substantially the same during the inspection with both apparatuses. When the third incident light projection unit 92b that does not use the objective lens is used, the spacer 47 is removed. Moreover, the objective plate 43 of both incident light projection units can be attached to and detached from the uniaxial stage 41.

  The insertion / removal of the incident light projection unit to / from the inspection optical axis will be described. At the time of epi-illumination observation, the light splitting deflection mirrors 7 of both epi-illumination light projecting units move to a position that coincides with the inspection optical axis 20. Since the objective lens and the epi-illumination projection unit are not required at the time of transmission observation, both the epi-illumination projection units do not block the transmission inspection light beam and are close to the image observation unit 90c close to the inspection member in order to focus on the member 1 to be examined. It can be separated from the optical axis at a position where it does not interfere.

  When switching from the reflected illumination inspection to the transmitted illumination inspection by the transmitted incident illumination spherical surface inspection device 92, a transmitted light projection lens case 45 for mounting the transmitted illumination lens 44 of the transmitted illumination device is attached in place of the incident illumination member mounting table 39. It is done. The transmission / projection lens case 45 is designed so that the epi-illumination objective lens group 90e used as the transmission / projection lens 44 during transmission observation can be easily attached and detached. Further, since the mounting position of the test member during the transmission illumination inspection is almost the same as that during the epi-illumination inspection, the centering of the test member 12 during the transmission observation is the same as the test member 1 during the epi-illumination observation. Coarse centering is performed at the inner edge of the opening.

  The centering device 91b is connected by a wing diaphragm 31a having a concentric aperture opening / closing lever 31c and a fixing screw 31b on the inspection optical axis 20, a rotating frame 33 for rotating and observing the member 1 to be examined, and the rotating frame 33 and screws. The outer diameter end face of the test member 1 is adjusted to match the position of the wing diaphragm. A height adjustment frame 35 for adjusting the height of the test member, a transmission test member that is dropped into the height adjustment frame 35 and has an inner diameter that holds the test member slightly smaller than the outer diameter of the test member A mounting table 38, an eccentric moving frame 32 for fine adjustment of eccentricity, a ball plunger 34 for finely moving the eccentric moving frame 32 to finely adjust the optical axis of the member to be inspected, and an eccentric frame 37 having an adjusting knob 36 are provided. Have. The test member is finely adjusted by the adjustment knob 36 after the coarse eccentricity adjustment of the core of the test member is made at the inner edge of the opening of the wing diaphragm 31a. The rotation function is for discriminating between a defect appearing in the image and a ghost of the optical system similar to the defect.

  The apparatus of the present invention is used to inspect spherical surfaces such as scratches, dirt, and undulations on the surface of a member having a spherical surface such as a wide range of curvature radius, spherical angle, aperture spherical or aspherical lens, mold for mold lens, and steel ball. Are suitable for transmission illumination inspection and epi-illumination inspection of a member to be examined.

DESCRIPTION OF SYMBOLS 1 Test member 1a Test surface curvature center 1b Test surface 1c Test surface center 3 Objective lens 3a Circular light source image 3b Objective lens Object side focal point 3c Primary image or primary image surface 3d Objective lens mounting plate 3e Stay member 3f Adapter frame 3g Objective lens frame 3h Objective lens object side principal point 3i Objective lens image side principal point 3j Objective lens image side focal point 4 Image relay lens 5 Imaging lens 6 Imaging element 6a Secondary image 7 Light splitting deflection mirror 8a Collimating lens 8af Collimating lens Focal plane 8b projection lens 8c image relay lens focal point 8d transmission collimating lens 8e interchange projection lens 8f interchange projection lens focal point 8g transmitted illumination circular light source image 9 circular light source 9a aperture plate 9b aperture 9c scattering plate 10 frame 11 Circular light source device 11a LED light source 11b LED light emitting surface 12 Transmission member 20 Inspection optical axis 21 Light projection axis 0 Zoom lens 31a Feather diaphragm 31b Fixing screw 31c Opening / closing lever 32 Eccentric moving frame 33 Rotating frame 34 Plunger 35 Height adjusting frame 36 Alignment knob 37 Eccentric frame 38 Transmitting test member mounting table 39 Incident test member mounting table 40 Stage Plate 41 Uniaxial stage 42 Deflection mirror housing 43 Objective plate 44 Transmission projection lens 45 Transmission projection lens case 46 Rotation knob 47 Spacer 48 Base plate 49 Deflection mirror 50 Movement guide 51 Dustproof glass 52 Deflection mirror base 53 Uniaxial stage 54 Rotation knob 55 Image observation unit column 56a Fixing screw a
56b Fixing screw b
57a Frame a
58b Frame b
59 Light source frame 60 Adjustment frame 90 Epi-illumination spherical surface inspection device 90a Test object placement moving base 90b Objective lens support base 90c Image observation unit 90d First epi-illumination projection unit A
90e Objective lens group 90f First incident light projection unit B
91 Epi-illumination illuminating spherical surface inspection device 91aa Second projection lens unit 91ab Third projection lens unit 91b Centering device 91c Transmission projection lens epi-illumination member mounting moving table 91d Second epi-illumination projection unit 91e Transmission Projection lens unit 91f Transmission projection unit 92 Epi-illumination illuminating spherical surface inspection device 92a Fourth projection lens unit 92b Third epi-projection unit 92e Transmission projection lens group 92g Focus of transmitted member a Circular light source b Light Split deflection mirror c Circular light source image d Test surface d1 Test surface d2 Test surface e Primary image e ″ e Secondary image e ″ e Secondary image e1 of test surface e1 Point e1 ′ e1 of test surface Primary image e2 at the virtual lens position of primary image e11'e1 Secondary image l of primary image e2 "e2 of point e2 'e2 on test surface Confocal distance f Objective lens focal distance f1 Objective lens focal distance f Imaging lens focal length h Pupil i Test surface curvature center k Telecentric configuration m Focal interval L1 Objective lens L2 Imaging lens L2 'Virtual lens position L3 Projection lens L4 Image relay lens R0 Test surface curvature radius R1 Test surface curvature Radius WD Working distance

According to an eighth aspect of the present invention, in the epi-illumination spherical surface inspection device according to the seventh aspect, the second epi-illumination projection unit is replaceable with the first epi-illumination projection unit and the first objective lens. And
Including the circular light source, the second light projection lens unit, the light splitting deflection mirror, and a second objective lens;
When the second incident light projection unit is provided between the image relay lens and the test member,
In the second incident light projection unit, the circular light source, the second light projection lens unit, and the light splitting deflection mirror are coaxially attached to an objective plate, and the second objective lens is the inspection optical axis. It is characterized by being mounted on the same axis.

The invention according to claim 10 is the epi-illumination spherical surface inspection device according to claim 7,
The third epi-illumination projection unit is replaceable with the first epi-illumination projection unit,
When the third incident light projection unit is provided between the image relay lens and the test member,
The third incident light projection unit is
The circular light source disposed on the projection axis;
An exchange projection selected from a group of exchange projection lenses having different numerical apertures or focal lengths that are arranged in an afocal light beam produced by the collimator lens and the collimator lens substantially in focus with the circular light source. A fourth light projection lens unit having a lens ;
A movement guide with a guide,
A light splitting deflection mirror,
The third incident light projection unit includes a set of the circular light source and the fourth light projection lens unit integrated with the light splitting deflection mirror attached to the objective plate coaxially with the light projection axis .
Said third vertical illuminator unit, the replacement light projecting lens moves make along on the light projection axis in the guide portion of the moving guide relative to the set that integrates said light splitting deflection mirror The circular light source image is sent to the inspection optical axis via the light splitting deflection mirror, and the circular light source image is moved on the inspection optical axis.

Next, the spherical angle, viewing angle, and illumination NA will be described with reference to FIG. The numerical aperture (NA) that forms the circular light source image 3a of each lens of the objective lens group is equal to the aperture angle that illuminates the entire surface 1b of the apparatus, and the outer diameter of the surface 1b that can be inspected and the surface to be inspected. Although it is 1/2 of the cone angle with the center of curvature of the surface 1b as the apex, it is referred to as a viewing angle in the present application. A larger viewing angle can be observed as the NA of the objective lens 3 is larger, so an objective lens having a larger NA is suitable for this apparatus. Moreover, 1/2 of the cone angle formed by the outer diameter of the surface 1b to be measured and the center of curvature is referred to as a spherical angle. Further, ½ of the cone angle that illuminates one point on the surface 1b to be examined from the circular light source image 3a is referred to as illumination NA. The illumination NA is such that the diameter of the circular light source image is φd, and the radius of curvature of the test surface 1b is r.
Illumination NA = d / (2r)
Calculated by An appropriate value of the illumination NA is experimental, but 0.005 to 0.05 is preferable.
The diameter φd of the circular light source image created by the objective lens is
φd = diameter of circular light source × (focal length of objective lens / focal length of collimating lens)
Calculated by
The illumination NA may be changed by replacing the aperture plates 9a having different aperture diameters 9b placed in contact with the scattering plate 9c of the circular light source device 11 shown in FIG. The light source is preferably an LED that emits visible light.

A second embodiment will be described. FIG. 6 shows an epi-illumination inspection apparatus 91 according to the second embodiment of the present invention. Similar to the first example, the epi-illumination inspection and the visible light transmission inspection of the test surface 1b having a small curvature radius and a large spherical angle. It is an inspection device that can perform a transmission illumination inspection of a member by switching.
The change from the first embodiment is that the uniaxial stage 41 instead of the objective lens support 90b is attached, and the first incident light projecting unit A 90d or the first incident light projecting unit B 90f to the second incident light projecting unit 91d. In addition, a centering device 91b and a transmission light projecting unit 91f for the test surface 1b are newly attached. As shown in FIG. 6, the first objective lens 3 in the first embodiment is not attached to the objective lens frame 3g, and is included as the second objective lens 3 in the second incident light projection unit 91d. ing.
The objective plate 43 is fixed to the uniaxial stage 41 via the spacer 47, and the second incident light projection unit 91d is connected to the inspection optical axis 20 at a position where the optical axis of the light splitting deflection mirror 7 substantially matches the transmitted illumination. The deflection mirror housing 42 can be moved and positioned to a position that does not block the transmission inspection light beam during transmission inspection during observation.

Claims (13)

An epi-illumination spherical surface inspection device for a test member having a test surface including a spherical surface or an aspherical surface on at least a part of the surface,
An objective lens group having different focal lengths or numerical apertures for creating a primary image of the test surface as a telecentric real image or virtual image of approximately 1 time;
An objective lens supporting base on which a first objective lens selected from the objective lens group is attached so as to be detachably interchangeable with other objective lenses;
A test member placement moving table for mounting the test member and moving the test member along an optical axis of the objective lens, that is, an inspection optical axis;
An image relay lens and an imaging lens that are substantially telecentric on the object side, i.e., the primary image side and the secondary imaging side, by relaying a primary image created by the first objective lens; An image observation unit that moves along the inspection optical axis, and a monitor that displays a signal from the image sensor as an image. When,
An optical axis orthogonal to the inspection optical axis, which can be formed by disposing a light splitting deflection mirror between the first objective lens and the image relay lens or between the image relay lens and the imaging lens, A circular light source disposed on the light projecting axis, a first light projecting lens unit, and the light splitting deflecting mirror; and a light beam formed by the first light projecting lens unit via the light splitting deflecting mirror. A first incident light projecting unit that sends a circular light source image to a focal position of the first objective lens and illuminates the size of the circular light source or the member to be examined. An epi-illumination spherical surface inspection apparatus characterized in that the numerical aperture, that is, the illumination NA is variable.   When the first incident light projection unit is between the image relay lens and the objective lens, the first incident lens unit of the first incident light projection unit is a collimator focused on the circular light source. A second light projecting lens unit including a lens, and sending an afocal light beam produced by the second light projecting lens unit to the first objective lens via a light splitting deflection mirror. The epi-illumination spherical surface inspection device according to claim 1.   When the first incident light projection unit is between the image relay lens and the imaging lens, the first incident lens unit of the first incident light projection unit is focused on the circular light source. A third projection lens unit having a collimating lens and a projection lens for producing a circular light source image, wherein the circular light source image produced by the third projection lens unit is conjugated with a focal point of the image relay lens; 2. The epi-illumination spherical surface inspection apparatus according to claim 1, wherein an afocal light beam is sent to the first objective lens via the light splitting deflection mirror and the image relay lens.   The size of the circular light source is such that an illumination NA for illuminating the test surface from the circular light source image created by the first objective lens is within a range of 0.005 to 0.05. The epi-illumination spherical surface inspection device according to any one of 1 to 3.   5. The imaging position of the circular light source created by each objective lens included in the objective lens group, that is, the focal position of the objective lens, is substantially the same position. Epi-illumination spherical surface inspection device as described in 1.   5. The epi-illumination spherical inspection according to claim 1, wherein a primary image position of the test surface created by each of the objective lenses included in the objective lens group is substantially the same position. 6. apparatus.   5. The epi-illumination spherical surface inspection apparatus according to claim 1, wherein the objective lens support base is detachable so as to match the inspection optical axis. The second epi-illumination projection unit is replaceable with the first epi-illumination projection unit,
Including the circular light source, the second light projection lens unit, the light splitting deflection mirror, and a second objective lens;
When the second incident light projection unit is provided between the image relay lens and the test member,
In the second incident light projection unit, the circular light source, the second light projection lens unit, and the light splitting deflection mirror are coaxially attached to an objective plate, and the second objective lens is the inspection optical axis. The epi-illumination spherical surface inspection device according to claim 7, wherein the epi-illumination spherical surface inspection device is attached to the same axis.   9. The epi-illumination according to claim 8, wherein the second epi-illumination light projecting unit is attached to a uniaxial stage movable along the light projection axis and can be inserted / removed substantially in alignment with the inspection optical axis. Spherical inspection device. The third incident light projection unit can be replaced with the first incident light projection unit,
When the third incident light projection unit is provided between the image relay lens and the test member,
The third incident light projection unit includes the circular light source disposed on the light projection axis,
An exchange projection lens selected from a group of exchange projection lenses having different numerical apertures or focal lengths, which are arranged in an afocal light beam produced by a collimator lens and a collimator lens substantially in focus with the circular light source. And a fourth projector lens unit having
In the third epi-illumination projection unit, the circular light source and the fourth projection lens unit pair having a guide that can move on the projection axis and the light splitting deflection mirror are coaxially objective. Mounted on the board,
In the third incident light projection unit, the pair of the circular light source and the fourth light projection lens unit moves on the light projection axis with respect to the light splitting deflection mirror along the guide portion of the moving guide, and is exchanged. 8. The epi-illumination according to claim 7, wherein the circular light source image formed by the light projecting lens is sent to the inspection optical axis via the light splitting deflection mirror, and the circular light source image is moved on the inspection optical axis. Lighting spherical inspection device.   11. The epi-illumination according to claim 10, wherein the third epi-illumination projection unit is attached to a uniaxial stage movable along the projection axis, and can be inserted / removed substantially in alignment with the inspection optical axis. Illumination spherical surface inspection device.   The image observation unit includes a zoom optical system between the image relay lens and the imaging lens, the image relay lens is an image relay lens having a different focal length or numerical aperture, or the imaging lens is a focal length or aperture. 12. The epi-illumination spherical surface inspection apparatus according to claim 1, wherein a plurality of imaging lenses having different numbers can be attached and detached. Any of the first to third incident light projection units includes a transmission light projection unit including a transmission light projection lens on the opposite side of any one of the first to third incident light projection units with the test member interposed therebetween. 13. A transmission epi-illumination spherical surface inspection apparatus capable of selectively performing a transmission illumination spherical surface inspection and an epi-illumination spherical surface inspection of the test surface. Transmitting epi-illumination spherical inspection device including the epi-illumination spherical inspection device described in 1.

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