JP2008076962A - Optical inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain an optical inspection apparatus capable of achieving the simplification and the cost reduction of an adjusting mechanism by reducing the number of adjusting elements, and that is easily operatable, and free from the positional fluctuation of the optical image resulting from the adjustment. <P>SOLUTION: An objective lens, a beam splitter and an imaging lens are positioned in order from an objective lens side, and an object is illuminated by the light made incident on the beam splitter, and a part of luminous flux of the light reflected by the object is shielded by a light shielding plate having an opening while placing the plate orthogonal to the optical axis, then, the diffraction is generated, then, the brightness change in the optical image in the non-uniform part of the object formed on the imaging surface is emphasized. In this case, if the light shielding plate is placed orthogonal to the optical axis between the beam splitter and the objective lens or between some lenses among the plurality of lenses constituting the objective lens, the brightness change in the optical image in the non-uniform part of the object imaged on the imaging surface can be emphasized most. Alternatively, in the case of using external light, the constitution having no beam splitter is allowed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention irradiates an object with light, and the reflected light or transmitted light gives the object surface uniformity (the presence or absence of irregularities) and the inside of the object (for example, the uniformity of the distribution of substances in the object). The present invention relates to an optical inspection apparatus for inspection.

  Uniformity of the surface of the object (for example, presence or absence of unevenness of about 1 micron to several tens of microns) and uniformity inside the object (in the present specification, this uniformity may be referred to as “object uniformity”) Even if the image is visually observed with a normal optical inspection apparatus (for example, an optical microscope) or image processing is performed on an image obtained by attaching a video camera or the like to the optical inspection apparatus, there is no object uniformity ( The brightness of the reflected or transmitted light in the part (which may be displayed as "non-uniform part of the object") (which may be displayed as "non-uniform part of the object") is almost unchanged (the contrast ratio is It is extremely difficult to determine the presence or absence of a non-uniform portion of the object. Therefore, a Nomarski differential interference inspection apparatus that can emphasize the change in the brightness of the optical image in the non-uniform portion of the object (can increase the contrast ratio) is frequently used.

  When using a Nomarski differential interference inspection apparatus, the contrast ratio of the optical image of the non-uniform part of the object can be increased. Therefore, in the case of visual inspection, the part that appears bright and swelled, and the shadow of the mountain The portion that looks dark like this can be made relatively conspicuous. As a result, when an optical image (two-dimensional image) of a non-uniform portion of an object is visually observed, it looks as if it is a three-dimensional image, and it becomes easy to determine (inspect) whether or not there is a non-uniform portion of the object.

Such a Nomarski differential interference inspection apparatus has, for example, an objective lens, a Nomarski prism, a half mirror (or a beam splitter), a lens group, and a rotatable analyzer (in the lens group) (on the first optical axis). A polarizing element) is positioned, and an optical image of the inspection object (sample) is formed on the imaging surface. Here, the light source that irradiates the inspection target object with illumination light is positioned on the second optical axis perpendicular to the first optical axis at the position where the half mirror is disposed, and between the light source and the half mirror. The polarizing plate is positioned. The light incident on the half mirror from the light source through the polarizing plate is reflected by the half mirror, and is irradiated onto the subject after passing through the Nomarski prism and the objective lens along the first optical axis. Then, the light reflected by the subject and incident on the objective lens again passes through the lens group having the Nomarski prism, the half mirror, and the analyzer, and forms an image on the imaging surface. In the Nomarski differential interference inspection system, in order to obtain a differential interference image with a high contrast ratio corresponding to the nonuniformity of the object, the polarization of the light incident on the half mirror from the light source is adjusted by rotating the polarizing plate, The differential interference between the light traveling and the light reflected by the subject is adjusted by a Nomarski prism, and the analyzer is further rotated (for example, Patent Documents 1 and 2).
JP-A-10-268200 JP 11-119107 A

  However, the Nomarski differential interference inspection apparatus has an adjustment mechanism of three adjustment elements and is expensive, and the three adjustment elements of the polarizing plate, the Nomarski prism, and the analyzer influence each other. Because it increases the contrast ratio of the differential interference image, a highly skilled operator is required to inspect (e.g., determine the uniformity of an object) an object to be inspected (for example, a microloelectronic component or a micromechatronic component). Since the position of the optical image on the imaging surface changes with the rotation of the analyzer (polarization element), sometimes the region to be inspected is outside the field of view (or the image region when using an area sensor). There is a problem of going out. In order to solve the above problems, the present invention can simplify and reduce the cost of the adjustment mechanism with fewer adjustment elements, and does not require a high level of skill for inspection (easy to operate). An optical inspection apparatus in which the position of an image does not change on the imaging surface is realized.

  In order to solve the above problems, an optical inspection apparatus according to the present invention positions an objective lens, a beam splitter, and an imaging lens on the optical path from the objective lens side, and forms an optical image of an object facing the objective lens. In an optical inspection apparatus that forms an image on an image plane, a light shielding plate having an opening is further provided between the beam splitter and the objective lens, or between any one of a plurality of lenses constituting the objective lens. Position the lens and the beam splitter on a plane that intersects the optical axis on the objective lens side, and the beam splitter reflects or transmits the light incident on the beam splitter from the light source toward the objective lens along the optical axis on the objective lens side. Irradiates the object and reflects the light reflected from the object and incident on the objective lens along the optical axis on the objective lens side. Has a configuration in which transmission or reflecting into.

  In the optical inspection apparatus having such a configuration, the opening of the light shielding plate is a light flux that is incident on the object from the beam splitter through the objective lens along the optical axis on the objective lens side and a light flux that enters the objective lens and travels toward the beam splitter. The light can be diffracted by the edge of the opening. The inventor has found that when the diffraction of the light is caused, the change in the brightness of the optical image corresponding to the non-uniform portion of the object is emphasized (contrast ratio is increased) (Claim 1). .

  The inventor positions at least the beam splitter and the imaging lens between the beam splitter and the imaging lens or between any of the plurality of lenses constituting the imaging lens. If it is positioned on a plane that intersects the optical axis on the imaging lens side, a part of the light beam that passes through the beam splitter through the beam splitter and goes to the imaging surface is blocked, and the light is diffracted by the edge of the aperture. It has been found that the change in the brightness of the optical image corresponding to the non-uniform portion of the object is emphasized (claim 2).

  In each of the above configurations (the configurations of claims 1 and 2), when the beam splitter reflects the light incident from the light source toward the objective lens and transmits the light incident from the objective lens to the imaging lens. The objective lens side optical axis and the imaging lens side optical axis form a single optical axis. On the other hand, when the beam splitter transmits light incident from the light source toward the objective lens and reflects light incident from the objective lens to the imaging lens, the objective lens side optical axis and the light source side optical axis are 1 Thus, the objective lens side optical axis and the imaging lens side optical axis intersect each other.

  Here, the optical inspection apparatus having the above configuration (claim 2) causes the light transmitted or reflected from the beam splitter to the imaging lens side to be diffracted by the edge of the opening of the light shielding plate. As described above, an object is illuminated with external light without a beam splitter, and a light shielding plate is provided between any one of a plurality of lenses included in the objective lens and a plurality of lenses included in the imaging lens. Positioning it on a plane that intersects the optical axis of the optical inspection device, the part of the light beam that enters the objective lens and travels toward the image plane along the optical axis is blocked by the edge of the aperture to cause diffraction in the light. Also, it is possible to emphasize the change in brightness of the optical image of the non-uniform part of the object. At this time, the object may reflect or transmit external light to the objective lens side.

  Here, the inventor can remarkably emphasize the change in the brightness of the optical image corresponding to the non-uniform portion of the object by positioning the edge of the opening in the vicinity of the optical axis where the light shielding plates intersect. ) Was found. Therefore, if the light shielding plate is movable in the intersecting direction with respect to the intersecting optical axes, the opening of the light shielding plate is positioned at the position where the change in the brightness of the optical image corresponding to the non-uniform portion of the object can be most emphasized. The edge can be positioned (Claim 5). If the light-shielding plate has a square or rectangular opening, one of the four edges of the light-shielding plate is positioned near the optical axis where the light-shielding plate intersects, and the optical image of the non-uniform portion of the object caused by light diffraction Changes in brightness can be coordinated (claim 6).

  Since the optical inspection apparatus according to claim 7 further includes an area sensor that converts an optical image of the object into an electric signal, a video signal (video signal) of the object output from the area sensor (for example, a video camera). Can be input to a computer or an image processing apparatus, and by displaying on a video monitor (picture monitor), a change in the brightness of the optical image corresponding to the non-uniform portion of the object can be easily recognized (object The uniformity inspection can be further facilitated).

  As described above, according to the optical inspection apparatus of the present invention, a part of the light beam is shielded by the light shielding plate, and the change in the brightness of the nonuniform portion of the object in the optical image of the object imaged on the imaging surface is emphasized. Further, by adjusting the light shielding state of the light beam, it is possible to remarkably emphasize the change in the brightness of the non-uniform portion of the object. Therefore, according to the optical inspection apparatus of the present invention, the adjustment elements can be reduced, the adjustment mechanism is simplified and the cost is reduced, and the adjustment elements are only the position adjustment of the aperture (adjustment of the light shielding state of the light beam). Since a high degree of skill is not required and an analyzer, which is a polarizing element, is not used, it is possible to prevent a change in the position of the optical image on the image plane due to the rotation of the analyzer.

  Hereinafter, an optical inspection apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a schematic configuration example of an optical inspection apparatus according to an embodiment (Example 1, optical inspection apparatus 10) according to the present invention.
An optical inspection apparatus 10 shown in FIG. 1 houses an objective lens 20 having a plurality of lenses, a light shielding plate 30, a beam splitter 40, an imaging lens 50 having a plurality of lenses, a light source 60, and these objective lenses 20 to 60. And a video camera 80 mounted on the lens barrel 70 on the imaging lens 50 side. Here, the objective lens side optical axis 11 where the objective lens 20, the light shielding plate 30 and the beam splitter 40 are positioned, and the imaging lens side optical axis 12 where the beam splitter 40 and the image lens 50 are positioned are one optical axis 13. The lens 81 of the video camera 80 (for example, a CCD video camera) is positioned on the optical axis 13. The lens 81 forms an optical image formed by the optical inspection apparatus 10 on a photoelectric surface of a CCD element, for example, included in the video camera 80.

  The light shielding plate 30 has a thickness of 5 mm, a width of 42 mm, a square-shaped opening 31 with a side of 30 mm, is located between the objective lens 20 and the beam splitter 40, and is arranged in the length direction of the light shielding plate 30. The lens barrel 70 is penetrated so as to be orthogonal to the objective lens side optical axis 11 and can be linearly moved in the penetration direction by a driving device (not shown) (for example, a deceleration driving device). The distance between the surface of the light shielding plate 30 on the beam splitter 40 side and the beam splitter 40 is 10 mm, and the distance between the surface of the light shielding plate 30 on the objective lens 20 side and the flange of the objective lens 20 is 25 mm. Further, the position of the light shielding plate 30 can be preset so that the objective lens side optical axis 11 is positioned substantially at the center of the opening 31.

  The beam splitter 40 includes prisms 41 and 42 having a cross section of a substantially right isosceles triangle, and a reflecting surface 43 is formed by making the bottom surfaces including the bottoms of the substantially right isosceles triangles face each other. The reflecting surface 43 is positioned so as to intersect the optical axis 13 at an angle of 45 degrees at the center, and the light source side optical axis 14 is orthogonal to the optical axis 13 at the center of the reflecting surface 43. The light source 60 includes, for example, an incandescent bulb 61 and a condenser lens 62, condenses the light emitted from the incandescent bulb 61 by the condenser lens 62, and irradiates the beam splitter 40 along the light source side optical axis 14. It is configured as follows.

  FIG. 2A is a plan view showing a relative positional relationship between the opening 31 of the rectangular light shielding plate 30 and the light beam 11 a along the objective lens side optical axis 11. The opening 31 is defined in a square shape by linear edges 31a and 31b orthogonal to the lengthwise center line 32a and linear edges 31c and 31d orthogonal to the widthwise centerline 32b. Is provided. Here, the light beam 11a is both a light beam directed in the direction of arrow A in FIG. 1 and a light beam directed in the direction of arrow B in FIG. 1 between the objective lens 20 and the beam splitter 40.

Next, adjustment of the optical inspection apparatus 10 in the case of inspecting the object 1 to be inspected (for example, a minute roelectronic component or a minute mechatronic component) will be described.
First, the object 1 is placed on the table 2 so as to face the objective lens 20 (FIG. 1), and the light shielding plate 30 is set at the preset position. Next, the incandescent lamp 61 is turned on to emit light from the light source 60 toward the beam splitter 40. Then, the light emitted from the light source 60 reaches the reflection surface 43 of the beam splitter 40 along the light source side optical axis 14, and the light reflected by the reflection surface 43 in the direction indicated by the arrow A in FIG. 43 is separated into light passing through 43. The light reflected by the reflecting surface 43 travels toward the objective lens 20 along the objective lens side optical axis 11 (note that the light transmitted through the reflecting surface 43 is transmitted through the beam splitter 40 and is, for example, black in the lens barrel 70). Absorbed by the painted inner surface). The light directed toward the objective lens 20 is not shielded by the light shielding plate 30 because the light shielding plate 30 is in the preset position, and is transmitted to the object 1 through the objective lens 20.

  The light thus irradiated on the object 1 is reflected by the surface of the object 1 when the reflectance of the surface of the object 1 is high, and when the vicinity of the surface of the object 1 transmits and reflects light, the surface or the inside of the object 1 is reflected. Reflected by. The light reflected by the object 1 and entering the objective lens 20 enters the beam splitter 40 along the objective lens side optical axis 11 in the direction indicated by the arrow B in FIG. The light incident on the beam splitter 40 is separated into light reflected by the reflecting surface 43 and light transmitted through the reflecting surface 43. The light that has passed through the reflecting surface 43 forms an optical image of the object 1 on the imaging surface by the imaging lens 50, so that this optical image can be picked up by the video camera 80 (note that it is reflected by the reflecting surface 43. Light travels toward the light source 60 along the light source side optical axis 14 and is absorbed by the inner surface of the lens barrel 70).

Next, adjustment for enhancing the change in the brightness of the optical image corresponding to the non-uniform portion of the object 1 will be described.
When the light shielding plate 30 is at the preset position, the optical axis 11 of the objective lens is located at the center of the opening 31, and the light shielding plate 30 does not shield the light beam 11a. Therefore, the optical inspection apparatus 10 operates in the same manner as a normal optical microscope. Thus, the change in brightness of the non-uniform portion of the object 1 is extremely small (see the image shown in FIG. 3A). Here, when the light beam 11a is blocked by the light blocking plate 30 as shown in FIG. 2A, light is diffracted by the linear edge 31a. The inventor has found that when this diffraction occurs, a change in the brightness of the optical image corresponding to the non-uniform portion of the object 1 is emphasized, as in the image shown in FIG. It has been found that such a change in the brightness of the optical image is emphasized even if the linear edge 31a is not just in contact with the optical axis 11 on the objective lens side. This is because when the linear edge 31a is brought closer to the vicinity of the objective lens side optical axis 11 while moving the light shielding plate 30 in the length direction, the brightness of the optical image corresponding to the non-uniform portion of the object 1 is increased. The change in height is gradually emphasized, and when the linear edge 31a intersects the objective lens side optical axis 11, the change in brightness of the optical image is most emphasized, and the linear edge 31a becomes the objective. This is because when the light shielding plate 30 shields light on the objective lens side optical axis 11 after crossing the lens side optical axis 11, the degree of enhancement gradually decreases.

  3C and 3D show changes in the brightness of the optical image when the light shielding plate 30 intersects the objective lens side optical axis 11 at a position closer to the objective lens 20 than the above position. FIGS. 3E and 3F show changes in the brightness of the optical image when the light shielding plate 30 intersects the objective lens side optical axis 11 at a position in the vicinity of the objective lens 20. ((C) and (e) in FIG. 3 are images when the light shielding plate 30 is in the preset position, and (d) and (f) in FIG. 3 correspond to the non-uniform portion of the object 1). In other words, when the light shielding plate 30 crosses the objective lens side optical axis 11 at a position relatively close to the beam splitter 40, the brightness change of the optical image is emphasized. The image of (b) can be obtained, and light is shielded closer to the objective lens 20 than this position. 3 is obtained by crossing the objective lens side optical axis 11 with the objective lens side optical axis 11, and the light shielding plate 30 intersects the objective lens side optical axis 11 at a position near the objective lens 20. As a result, the images shown in FIGS. 3E and 3F can be obtained.

  Thus, there is no special restriction on the positional relationship between the light shielding plate 30, the opening 31, and the linear edge 31a with respect to the direction of the objective lens side optical axis 11 (for example, restrictions such as positioning the edge at the focal point as in the Schlieren method). In addition, the straight edge 31a may not have a sharp edge shape), and if the light shielding plate 30 blocks a part of the light beam 11a between the beam splitter 40 and the objective lens 20, the straight edge 31a does not have a sharp edge shape. The diffraction of the light generated at the edge 31a emphasizes the change in the brightness of the optical image corresponding to the non-uniform portion of the object 1, and the change in brightness is caused by the linear edge 31a on the objective lens side optical axis 11 or 11. When placed in the vicinity, it is most emphasized.

  Therefore, for example, while taking an optical image of the optical inspection apparatus 10 with the video camera 80 and visually observing it with a video monitor or the like, a reference sample (reference sample for adjusting the optical inspection apparatus 10) having a non-uniform portion is placed on the table. After adjusting the focal point of the objective lens 20 on the reference sample 2, the light shielding plate for the optical axis 11 on the objective lens side so that the contrast of the image of the non-uniform portion in the reference sample is most emphasized. After the position of 30 is adjusted, the presence or absence of a non-uniform portion of the object 1 can be easily inspected by viewing the image of the object 1 instead of the reference sample.

  For example, FIG. 4A shows a waveform for explaining a change in contrast of the video signal in the scanning line Ha of the image (FIG. 3A) obtained by imaging the object 1 when the light shielding plate 30 is positioned at the preset position. FIG. 4B shows a scanning line Hb (scanning position corresponding to the scanning line Ha) of an image (FIG. 3B) obtained by imaging a non-uniform portion of the object 1 when the contrast of the optical image is enhanced. (Line) is a waveform for explaining the contrast change of the video signal (FIG. 4 shows only the change (AC component) of the video signal in order to explain the contrast change).

  As described above, the optical inspection apparatus 10 can enhance the contrast of the optical image corresponding to the non-uniform portion of the object 1. Therefore, when the image captured by the video camera 80 is monitored, the non-uniform portion of the object 1 appears as if it is three-dimensional. It can be visually recognized like an image, and it becomes easy to determine the presence or absence of an uneven portion of an object. Further, as shown in FIG. 4B, the contrast of the video signal is enhanced (the change in the level of the video signal is enhanced), so that the level difference of the video signal can be easily detected. This makes it easier to find non-uniform parts.

  In FIG. 1, the objective lens side optical axis 11 and the imaging lens side optical axis 12 form one optical axis 13 and the light source side optical axis 14 is orthogonal to the optical axis 13, but the objective lens side optical axis. 11 and the light source side optical axis 14 may form one optical axis, and the imaging lens side optical axis 12 may be configured to be orthogonal to the one optical axis (that is, in FIG. It is also possible to replace the positions of the imaging lens 50 and the light source 60 and the like). If the reflected light of the light source 60 can be guided to the imaging lens 50, the intersection angle between the reflecting surface 43 and the optical axis 13 (or the objective lens side optical axis 11) is not limited to 45 degrees.

FIG. 5 is a diagram showing a schematic configuration example of another example (Example 2, optical inspection apparatus 15) of the optical inspection apparatus according to the present invention. In addition, the same code | symbol is attached | subjected to the component which has the function similar to the optical inspection apparatus 10, and the description is abbreviate | omitted.
The optical inspection device 15 is different from the optical inspection device 10 in that the light shielding plate 30 is located between the beam splitter 40 and the imaging lens 50. As a result of having such a configuration, in the optical inspection device 15, it is reflected from the surface or inside of the object 1, enters the objective lens 20, and is a beam splitter along the objective lens side optical axis 11 in the direction indicated by the arrow B in FIG. The light incident on the light beam 40 and transmitted through the reflection surface 43 of the beam splitter 40 is diffracted by the linear edge 31a of the opening 31 of the light shielding plate 30, and the optical image of the object 1 is formed on the imaging surface by the imaging lens 50. Is imaged.

  Also in the optical inspection device 15, the contrast of the image of the non-uniform portion of the object 1 is enhanced. For example, FIG. 6A is an optical image when the light shielding plate 30 is in the preset position (when the optical inspection device 15 operates in the same manner as a normal optical microscope), and FIG. It is an image of an optical image when the linear edge 31a is positioned in the vicinity of the imaging lens side optical axis 12 (when the change in the brightness of the optical image corresponding to the non-uniform portion of the object 1 is emphasized).

  Thus, also in the optical inspection apparatus 15, when the light shielding plate 30 blocks a part of the light beam 12a between the beam splitter 40 and the imaging lens 50 as shown in FIG. The diffraction of the generated light emphasizes the change in the brightness of the optical image corresponding to the non-uniform portion of the object 1. When placed in the vicinity, it is most emphasized. Here, the light shielding plate 30 can be positioned at an arbitrary position between the beam splitter 40 and the imaging lens 50 because there is no restriction such as positioning the linear edge 31a at the focal point of the optical inspection device 15. .

  In FIG. 2B, the linear edge 31b opposite to the linear edge 31a of the opening 31 is positioned in the vicinity of the imaging lens side optical axis 12 and blocks a part of the light beam 12a (FIG. 2 ( In FIG. 3 (b), FIG. 2 (b), and FIG. 2 (b), the change in the brightness of the optical image of the non-uniform portion of the object 1 is the same. ) Is emphasized by the reverse polarity. That is, the unevenness when viewing the image of FIG. 6B is opposite to that of FIGS. 3B, 3D, and 3F. When the change in contrast of the video signal on the scanning line Hc (scanning line corresponding to the scanning line Ha) in FIG. 6B is shown as a waveform, it can be shown in FIG. When (b) is compared with FIG. (C), the emphasized change in brightness is of opposite polarity.

FIG. 7 is a diagram showing a schematic configuration example of another embodiment (third embodiment, optical inspection device 16) of the optical inspection device according to the present invention. In addition, the same code | symbol is attached | subjected to the component which has the function similar to the optical inspection apparatuses 10 and 15, and the description is abbreviate | omitted.
In the optical inspection device 15 described above, the linear edge 31a of the opening 31 of the light shielding plate 30 causes diffraction of the light beam 12a traveling from the beam splitter 40 to the imaging lens 50. It does not cause diffraction in the light beam reflected from 40 toward the objective lens 20 along the objective lens side optical axis 11. Therefore, as shown in FIG. 7, even if the beam splitter 40 and the light source 60 are not provided, the light shielding plate 30 having the opening 31 is disposed between the objective lens 20 and the imaging lens 50 with the light of the optical inspection device 16. Even if it is positioned on a plane that intersects with the axis 13, if the object 1 is irradiated with light from the external light source 60 ′, the light shielding plate 30 becomes the objective lens 20 and the imaging lens 50 as shown in FIG. A part of the light beam 13a between the first and second beams can be blocked, and the diffraction of light generated at the linear edge 31a emphasizes the change in the brightness of the optical image corresponding to the non-uniform portion of the object 1, and this optical image This change in brightness is most emphasized when the linear edge 31a is positioned at or near the optical axis 13. In this way, the optical inspection device 16 can emphasize the change in the brightness of the optical image corresponding to the non-uniform portion of the object 1.

  In the optical inspection device 15, as described above, the positional relationship among the light shielding plate 30, the opening 31 and the linear edge portion 31a on the imaging lens side optical axis 12 is not particularly limited. In addition, the light shielding plate 30 can be positioned on a plane intersecting the optical axis 13 between any one of the plurality of lenses included in the objective lens 20 and the plurality of lenses included in the imaging lens 50. If the object 1 transmits light, the light from the external light source 60 ′ may be transmitted through the object 1 so that the transmitted light enters the objective lens 10.

  Needless to say, the present invention is not limited to the above-described embodiments, and can be modified without departing from the spirit of the present invention. For example, the opening of the light shielding plate may have a rectangular shape or an arbitrary shape as long as diffraction can occur, and the light shielding plate may not be orthogonal to the intersecting optical axes as long as diffraction can occur. The beam splitter is not limited to a prism, and may be a half mirror or another configuration as long as incident light can be separated into two optical paths. The light source that makes light incident on the beam splitter may be a light source that is separated from the lens barrel and that makes light incident along the light source side optical axis via an optical fiber or the like. When a video camera is mounted, the video camera lens substantially constitutes a lens on the imaging side, and the present invention is not intended to exclude the video camera lens from the imaging lens. Of course, it is possible to inspect for the presence or absence of an uneven portion of an object by visual observation without using a video camera.

It is a figure which shows the example of a schematic cross-section structure of the optical inspection apparatus in one Example (Example 1) of this invention. It is a top view which shows the positional relationship of the opening of the light-shielding plate in the optical inspection apparatus concerning this invention, and a light beam. It is an example of an image of the non-uniform | heterogenous part of the object by the optical inspection apparatus of FIG. It is a figure explaining the example of the video signal waveform of one scanning line of the image by the optical inspection apparatus of the present invention. It is a figure which shows the schematic cross-section structural example of the optical inspection apparatus in the other Example (Example 2) of this invention. 6 is an image example of a non-uniform portion of an object by the optical inspection apparatus of FIG. It is a figure which shows the schematic cross-section structural example of the optical inspection apparatus in the other Example (Example 3) of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 15, 16 Optical inspection apparatus 11 Objective lens side optical axis 12 Imaging lens side optical axis 13 Optical axis 11a, 12a, 13a Light beam 20 Objective lens 30 Light-shielding plate 31 Aperture 31a, 31b, 31c, 31d Linear edge ( Edge)
40 Beam splitter 50 Imaging lens 80 Video camera (area sensor)

Claims (7)

In the optical inspection apparatus that positions the objective lens, the beam splitter, and the imaging lens from the objective lens side, and forms an optical image of an object facing the objective lens on the imaging surface,
A light-shielding plate having an opening further includes at least the objective lens and the beam splitter between the beam splitter and the objective lens, or between any one of a plurality of lenses constituting the objective lens. Positioned on the plane that intersects the optical axis on the objective lens side,
The beam splitter reflects or transmits the light incident from the light source toward the objective lens along the objective lens side optical axis and irradiates the object, and is reflected by the object and is reflected on the objective lens side optical axis. Transmitting or reflecting the light incident on the objective lens along the imaging lens,
The opening of the light-shielding plate is configured to divide a part of a light beam incident on the object through the objective lens from the beam splitter along the objective lens side optical axis and a part of the light beam incident on the objective lens and traveling toward the beam splitter. An optical inspection apparatus characterized in that a change in brightness of an optical image of a non-uniform portion of the object imaged on the imaging surface is emphasized by blocking and generating diffraction. In the optical inspection apparatus that positions the objective lens, the beam splitter, and the imaging lens from the objective lens side, and forms an optical image of an object facing the objective lens on the imaging surface,
A light shielding plate having an opening is further provided at least between the beam splitter and the imaging lens, or between any one of the plurality of lenses constituting the imaging lens. Is positioned on a plane that intersects the optical axis on the imaging lens side,
The beam splitter reflects or transmits light incident from a light source toward the objective lens along the objective lens side optical axis and irradiates the object, and is reflected by the object and is reflected on the objective lens side optical axis. Transmitting or reflecting the light incident on the objective lens along the imaging lens,
An optical image of an inhomogeneous portion of the object imaged on the imaging surface, with the opening of the light shielding plate blocking the part of the light beam that passes through the beam splitter and directed to the imaging surface to cause diffraction. An optical inspection apparatus characterized by emphasizing a change in brightness. In the optical inspection apparatus that positions the objective lens and the imaging lens from the objective lens side and forms an optical image of the object facing the objective lens on the imaging surface,
A light shielding plate having an opening, and an optical axis that positions the objective lens and the imaging lens between any one of the plurality of lenses of the objective lens and the plurality of lenses of the imaging lens; Positioned in the intersecting plane,
The opening of the light-shielding plate is incident on the objective lens along the optical axis and shields a part of the light beam traveling toward the imaging surface to generate diffraction, so that the object imaged on the imaging surface An optical inspection apparatus that emphasizes a change in brightness of an optical image of a non-uniform portion.   The optical inspection apparatus according to claim 1, wherein an edge of the opening is positioned in the vicinity of an optical axis where the light shielding plate intersects.   The optical inspection apparatus according to claim 4, wherein the light shielding plate is movable in an intersecting direction with respect to an optical axis at which the light shielding plate intersects.   The optical inspection apparatus according to claim 5, wherein the opening of the light shielding plate has a square shape or a rectangular shape. In the optical inspection device according to any one of claims 1 to 3,
An optical inspection apparatus further comprising an area sensor for converting an optical image of the object into an electrical signal.

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