JP2000019062A - Optical member-inspecting apparatus and holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holder which can hold an optical member to be inspected, in a simple operation without touching a front face of the member. SOLUTION: A main body part 230 of a holder 23 has an inner face with a radius to a center axis O which is approximately equal only at two points to an optical member 27 to be inspected and is larger at the other area than the optical member 27. A movable block is held by a link mechanism at points opposite to the two points via the center axis O at the inner face of the main body part 23. The movable block is urged at all times by tension springs 242 to project towards the center axis O.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member inspection apparatus for detecting a cause of a defect of an optical member such as a lens, and a holder for mounting an optical member on the optical member inspection apparatus.

[0002]

2. Description of the Related Art An optical member such as a lens or a prism is used to refract an incident light beam regularly or to travel in parallel.
It is designed to converge or diverge at one point or linearly. However, when lint or the like is mixed in the optical member during the formation of the optical member (so-called “burr”), scratches or the like are generated on the surface of the optical member due to human handling after molding, Since the incident light flux is disturbed, desired performance cannot be obtained.

[0003] For this reason, various optical member inspection apparatuses for automatically detecting the cause of a defect in an optical member and automatically determining the quality of the optical member have been proposed. For example, the present applicant discloses in Japanese Patent Application No. 9-50760 that this inspection is performed by using an imaging optical system and a line sensor arranged on the optical axis while rotating the optical member to be inspected around its optical axis. An optical member inspection apparatus that images a target optical member and generates image data in a polar coordinate system has been proposed.

[0004] These optical member inspection apparatuses are provided with a holder for holding a peripheral edge of an end surface of the optical member to be inspected in order to hold the optical member to be inspected so that illumination light can pass therethrough. FIG. 9 shows the shape of a typical holder conventionally used. As shown in FIG. 9, the conventional holder has a shape in which a stepped portion 102 which is lowered by one step to fit a peripheral edge of a lens which is an optical member is formed on an inner edge of an opening in an upper end surface 101 of a cylindrical member 100. have.

[0005]

However, when the convex surface of the lens is held by the conventional holder having such a shape, that is, when the convex surface of the lens is fitted to the step portion 102 with the convex surface facing downward, the convex surface is required. May be damaged by contacting the inside of the outer edge of the step with the edge of the stepped portion 102.

The present invention has been made in view of such a problem in the conventional holder, and an object thereof is to provide a holder capable of holding an optical member to be inspected by a simple operation without contacting the surface thereof. Is to provide.
Another object of the present invention is to provide an optical member inspection apparatus including such a holder.

[0007]

The present invention has the following features to attain the object mentioned above.

[0008] That is, the invention according to claim 1 is a holder for holding an optical member therein, wherein the frame member abuts on the side surface of the optical member at at least two contact points; A movable member that is movably attached to the frame member and that is urged to abut the side surface of the optical member and press the optical member to each of the contact points. Features.

With this configuration, at least two contact points on the frame member and the movable member urged toward each of the contact points press against the side surface of the optical member,
This optical member is sandwiched and held. Therefore, since no member of the holder comes into contact with the surface of the optical member, the holder does not scratch the surface of the optical member.

At least two contact points on the frame member may be formed as a series of points in surface contact with the side surface of the optical member, or each point contact with the side surface of the optical member. It may be configured as a point. In the latter case,
The number of contact points may be three or more, but if it is two, the diameter of the optical member that can be held can have a certain width. The movable member may be configured integrally with a biasing unit made of an elastic member such as a spring or rubber, or may be configured as a member separate from these biasing units. Further, the moving trajectory of the movable member may be linear or arcuate.

According to a second aspect of the present invention, the frame member of the first aspect is a cylindrical member for holding the optical member therein, and the radius of the inner surface of the frame member is only at the contact point. The diameter is substantially the same as the radius of the optical member, and the other portions are specified to be larger than the radius of the optical member.

According to a third aspect of the present invention, in the frame member according to the second aspect, a portion facing each of the contact points across a space for holding the optical member is cut out to dispose the movable member. It is the one that has been identified.

According to a fourth aspect of the present invention, the movable member of the first aspect is attached to the frame member via a link mechanism, and is urged toward the contact point by a spring. That is what was specified.

The invention according to claim 5 specifies the link mechanism according to claim 4 as being constituted by link members arranged in a parallelogram shape.

Further, the invention according to claim 6 is characterized in that a high friction member is attached to each contact point of claim 1 and a portion of the movable member that contacts the optical member. Things.

According to a seventh aspect of the present invention, there is provided an optical member inspection apparatus for irradiating an optical member with illumination light from one side and photographing from the other side to obtain image data used for inspection. In the device, a frame member that contacts the side surface of the optical member at at least two contact points, and is attached to the frame member movably toward each of the contact points, and contacts the side surface of the optical member. A movable member biased so as to press the lever optical member to each of the contact points.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. <Configuration of Optical Member Inspection Apparatus> A schematic configuration of an optical member inspection apparatus according to an embodiment of the present invention is shown in a partial cross-sectional view of FIG. As shown in FIG. 1, the optical member inspection apparatus is configured by stacking an imaging device 1, an optical member holding unit 2, a diffusion plate holding unit 3, and a light source 4 from above. Among them, the imaging device 1, the diffusion plate holding unit 3, and the light source 4 are coaxially arranged with each other. Also, the optical member holding unit 2
Are arranged such that the center axis O thereof is slightly offset from a line (photographing optical axis l) passing through the center of each of the parts 1, 3, and 4.

The light source 4 includes a light guide fiber 41 for transmitting illumination light emitted from a light source lamp (not shown).
And a light distribution unit 42 in which the distal ends of the light guide fibers 41 are arranged side by side in the left-right direction in the figure.

The diffusion plate holding portion 3 is fixed to a frame (not shown) of the optical member inspection apparatus and has a circular opening 3.
A holding plate 31 with a hole 1a, a flat circular diffusion transmission plate 32 inserted into the opening 31a, and a long side thereof are attached to the surface of the diffusion transmission plate 32 with the long side thereof facing left and right in FIG. It is composed of a strip-shaped light shielding plate 33. The diffuse transmission plate 32 emits illumination light from the entire area thereof, and the light shielding plate 33 shields a part of the illumination light.

The optical member holding portion 2 is fixed to a frame (not shown) of the optical member inspection apparatus and has a rotary table support 20 integrally formed with a cylindrical lens barrel 20a.
And a disk-shaped rotary table 22 rotatably mounted on the lens barrel 20a via a bearing 21 and a through hole 22a formed coaxially with the lens barrel 20a at the center of the rotary table 22. An annular holder 23 removably mounted on the rotary table 22; a ring-shaped driven gear 24 mounted around the rotary table 22;
And a motor 26 that rotationally drives a driving gear 25 that meshes with the motor. The through hole 22a of the rotary table 22 has a light source side (lower side) half slightly smaller in diameter than the outer diameter of the holder 23, and an imaging device side (upper side) half of which has substantially the same diameter as the outer diameter of the holder 23. It has become. The holder 23 is locked to the step formed by this. A key groove 22b that engages with a key 231 of the holder 23, which will be described in detail later, is cut out in a part of the large-diameter portion on the upper end side of the through hole 22a. Therefore,
The holder 23 cannot rotate relative to the turntable 22. The inspection target optical member 27 is coaxially held inside the holder 23. As a result, when the motor 26 rotates the drive gear 25, the holder 23 and the inspection target optical member 27 rotate about the central axis O thereof.

The image pickup apparatus 1 has an objective lens 11 whose optical axis 1 is offset in parallel with the central axis O, and a position conjugate with the surface of the optical member 27 to be inspected with respect to the objective lens 11. And a line sensor 12. The line sensor 12 is disposed in parallel with the radial direction of the inspection target optical member 27 and in parallel with the long side of the light shielding plate 33 (in the horizontal direction in FIG. 1). Therefore, the line sensor 12 can image the inspection target optical member 27 over the entire area in the radial direction. However, in the above-mentioned light-shielding plate 33, the light (illumination light) emitted from the diffusion plate 32 is used for the range of the imaging target optical member 27 to be imaged by the line sensor 12 (the range conjugate with the imaging surface of the line sensor 12 with respect to the objective lens 11). ) Is adjusted in size and position so that the light does not pass through the line sensor 12 directly. Therefore, the inspection target optical member 2
As long as there is no shape defect in 7 (scratch or dust on the surface, fluff in the inside), the image picked up by the line sensor 12 (the luminance value of each pixel of the line sensor 12) is dark over the entire area. On the other hand, when there is a shape defect in the inspection target optical member 27 in the range to be imaged by the line sensor 12, light scattered by the shape defect enters the line sensor 12 via the objective lens 11. An image of the shape defect is formed on the imaging surface of the line sensor 12. Image data from the line sensor 12 that captures this image is stored in an A /
The signal is converted into a digital signal by a D converter and output to an image processing device (not shown).

Next, a specific configuration of the holder 23 will be described with reference to FIGS. FIG. 2 is an enlarged sectional view of the holder 23 showing the same cross section as FIG.
Is a side view of the holder 23 viewed from the same direction. 4 and 5 are a plan view and a bottom view of the holder 23, respectively. FIG. 6 is an exploded plan view showing the holding mechanism by removing only the cover 232 from the state shown in FIG. 7 and 8 are an exploded plan view and a side view showing the state of the holder 23 when the optical member is attached and detached, respectively.

As shown in these figures, the holder 23
Has a substantially cylindrical shape as a whole, and a main body portion 230 as a frame member occupying most of the main body portion;
A holding mechanism M constructed in a space formed by partially cutting out a part 0, and a cover 232 covering the holding mechanism M
Therefore, it is roughly configured. The key 231 described above is
It has a prismatic shape with its major axis oriented parallel to the direction of the central axis O, and is screwed and fixed at one position on the outer peripheral surface of the main body 230. In the following description, this key 231
Is defined as an "X meridian", and a diameter orthogonal to the X meridian is defined as a "Y meridian".

Although the outer peripheral surface of the main body 230 is formed as a substantially cylindrical surface, the inside of the main body 230 is closer to the photographing device 1 along the direction of the central axis O as shown in FIG. It is divided into a small inner diameter portion 230a located and a large inner diameter portion 230b located near the diffusion plate holding portion 3.

The shape of the large-diameter portion 230b is a rotationally symmetric cylindrical shape, and the inner peripheral surface thereof is
The cylindrical surface has a diameter sufficiently larger than 7.

The thickness of the small inner diameter portion 230a is sufficiently larger than the thickness of the optical member 27 to be inspected, and in the example of FIG. 2, is approximately twice the thickness of the optical member 27 to be inspected. However, the planar shape of the small inner diameter portion 230a changes along the circumferential direction. In other words, the inner diameter of the small inner diameter portion 230a is a constant diameter slightly larger than the optical member 27 to be inspected at a portion apart from the key 231 with the Y meridian as a boundary, but is closer to the key 231 than the Y meridian. Is gradually changing. Specifically, the inner diameter of the small inner diameter portion 230a is reduced most at a position (minimum diameter position α, β) shifted by +/− 30 degrees about the center line O with respect to the X meridian, and the optical member to be inspected. The outer diameter is almost the same as 27. At these two minimum diameter positions α and β, silicon rubber 233 as a high friction member is embedded in the inner surface of the small inner diameter portion 230a, respectively. Line contact in high friction state.
That is, these minimum diameter positions α and β function as contact points. In the vicinity of these minimum diameter positions α and β,
The inner surface of the small inner diameter portion 230a is substantially flat.

The small inner diameter portion 230a is separated from the key 231 on the X meridian by a portion separated from the key 231 by a line Y1 parallel to the Y meridian and displaced in the opposite direction from the key 231. All are cut out except for the support pillar 230c formed at the symmetrical position. That is, a portion facing each of the minimum diameter positions α and β across the space for holding the inspection target optical member 27 is notched. A concave portion formed by the notch (hereinafter, referred to as “mechanism housing portion S”)
Then, the above-described holding mechanism M is constructed. Hereinafter, a specific configuration of the holding mechanism M will be described.

Now, as shown in FIG. 6, a line Y orthogonal to the X meridian through the mechanism housing portion S and the optical member 27 to be inspected.
Assume 2. On the bottom surface of the mechanism accommodating portion S, screw holes (not shown) are formed at two positions on the line Y2 that is line-symmetric with respect to the X meridian. In each of these screw holes, one end of two long plate-like link arms 234 and 234 having the same size and shape are turned by screws 235 and 235 in a plane orthogonal to the central axis O. It is movably mounted. At the other ends of the link arms 234 and 234, the ends of a long plate-shaped parallel moving plate 236 having the same length as the distance between the screws 235 and 235 are rotated by the screws 237 and 237, respectively. Mounted freely. Thereby, the translation plate 236
Moves toward and away from the central axis O while maintaining a posture parallel to the Y meridian. That is, the link arms 234 and 234 and the translation plate 236 are link members arranged in a parallelogram shape, and constitute a link mechanism.

At the center of the parallel moving plate 236, a movable block 238 as a movable member having substantially the same thickness as the depth of the mechanism housing portion S is fixed. A side surface of the movable block 238 facing the center axis O (hereinafter, referred to as a “movable holding surface 238a”) is parallel to the side edge of the parallel movement plate 236 and the center axis O, and is located on the side of the parallel movement plate 236. It protrudes toward the central axis O from the edge. This movable holding surface 238
Also in a, a silicon rubber 239 is embedded as a high friction member that is in line contact with the side surface (edge) of the inspection target optical member 27 in a high friction state. In addition, the movable block 2
The plane shape of 38 is a shape in which both ends at the outer edge are chamfered obliquely. Then, the movable block 238 slides on the bottom surface of the mechanism housing portion S integrally with the parallel moving plate 236, and moves toward the minimum diameter positions α and β.

One screw 2 on the bottom of the mechanism housing S
In the vicinity of 35, a stopper pin 244 is implanted. The stopper pin 244 is connected to the optical member 27 to be inspected.
When the movable holding surface 238a approaches the minimum diameter positions α and β far beyond the outer edge of the inspection target optical member 27 (shown by a two-dot chain line in FIG. 6) in a state where there is no The movement is prevented by abutting the.

On the bottom surface of the mechanism accommodating portion S, fixed spring hooking pins 240 are respectively provided at positions displaced from the position of each screw 235 by an equal distance toward the central axis O in parallel with the X meridian.
Has been planted. On the other hand, each link arm 234, 23
A movable spring hook pin 241 is also implanted at the center of each of the four. And between each fixed spring hooking pin 240 and each movable spring hooking pin 241, a tension spring 24
2,242. Accordingly, the movable block 238 is constantly urged by the tension springs 242 and 242 in a direction approaching the minimum diameter positions α and β. However, as shown in FIG.
At the dead center where the 0, the screw 235 and the movable spring hook pin 241 are aligned in a straight line, the movable block 238 is stabilized without applying an urging force. In addition, at this dead point,
One of the link arms 234 is connected to the stopper pin 244 described above.
Comes into contact with each other, so that both link arms 23
4,234 is prevented from rotating counterclockwise in FIG.

Areas of a constant width which are shifted from the edge (line Y1) of the notch in the small inner diameter portion 230a toward the Y meridian side are used as the mounting margins 230d for the cover 232 described above.
The surface is recessed by the thickness of the cover 232. As shown in FIG. 4, the above-described cover 232 is stretched between the two mounting margins 230d, 230d, and is fixed to the support pillar 230c at an intermediate portion thereof. The cover 232 is an arc-shaped plate having the same width and the same diameter as the large inner diameter portion 230b. This cover 232
Has been cut out in the movable range to allow the movable block 238 to move. However, notches are not formed in the moving range of the movable block 238 when it is assumed that the link arms 234 and 234 have rotated in the opposite direction (counterclockwise in FIG. 6) beyond the above-mentioned dead center. .

The large-diameter portion 23 of the main body 230
The outer edge on the 0b side has a one-step narrow diameter, and an annular ring member 243 is fitted therein and fixed by screws. <Operation of Embodiment> A case where the concave surface of the meniscus lens as the inspection target optical member 27 is inspected using the optical member inspection apparatus and the holder 23 according to the present embodiment configured as described above will be described.

First, the operator removes the holder 23 from the turntable 22 of the optical member inspection device. At this time, since the inspection target optical member 27 is not mounted on the holder 23, the movable block 238 is most moved along the center axis O.
The side protruding to the side contacts the stopper pin 244.

Next, the operator operates the tension springs 242,
242, each link arm 234, 234
Is rotated counterclockwise in FIGS. 4 and 6 to obtain FIG.
And as shown in FIG. 8, it stabilizes at the above-mentioned dead center. In this state, the minimum diameter portions α and β and the movable holding surface 23
Since the distance from the optical member 8a is sufficiently larger than the diameter of the optical member 27 to be inspected, the optical member 27 to be inspected can be attached and detached. Thereafter, the operator places the holder 23 upside down on a horizontal and flat table.

Next, the operator grips the side surface (edge) of the optical member 27 to be inspected with the concave surface facing down and the convex surface facing upward, and attaches the optical member 27 to be inspected to the small inner diameter portion 230a. Put inside. At this time, only the outer edge of the concave surface of the inspection target optical member 27 comes into contact with the surface of the table, and nothing comes into contact with the concave surface, so that the concave surface is not damaged. Further, since the upper surface of the holder 23 is in surface contact with the upper surface of the table, and the outer edge of the concave surface of the optical member 27 to be inspected is in contact with the upper surface of the table over the entire circumference. It can be held horizontally.

Next, the operator operates each link arm 23.
7, the movable holding surface 238a of the movable block 238 is projected toward the center axis O. In the process of this projection, the movable block 23
8, the movable holding surface 238a abuts against the side surface of the inspection target optical member 27, and further pushes and moves the inspection target optical member 27 due to the restoring force of each of the tension springs 242, 242. 230a, the smallest diameter portion α on the inner surface,
Press on β. As a result, the inspection target optical member 27 is
The minimum diameter portions α and β that contact the side surface and the movable holding surface 238
a, and is held in the holder 23.

Next, the operator turns the holder 23 upside down and turns the through-hole 22 of the rotary table 22 of the optical member inspection apparatus.
a. At this time, as described above, the holder 2
The third key 231 is engaged with the key groove 22b of the turntable 22.

After setting the holder 23 as described above, the operator causes the light distribution section 42 of the light source 4 to emit illumination light. As a result, the image is captured by the line sensor 12 of the image capturing apparatus 1 as described above, and the image data obtained by the image capturing is stored in the image memory of the image processing apparatus (not shown). Such imaging is performed by the optical member holding unit 2.
Of the optical member 27 to be inspected by the turntable 21
This is performed every time when every three rotations are made by a predetermined unit angle. Then, based on the image data stored in the image memory while the inspection target optical member 27 rotates 360 degrees, an image processing apparatus (not shown) determines the quality of the inspection target optical member 27.

After the inspection is completed, the operator removes the optical member 27 to be inspected from the holder 23 by performing an operation completely opposite to that described above.

As described above, according to the holder 23 of the present embodiment, since the inspection target optical member 27 is held by sandwiching the side surface of the inspection target optical member 27, regardless of the surface shape of the inspection target optical member 27. The inspection target optical member 27 can be attached and detached by a simple operation without damaging the surface of the inspection target optical member 27.

[0042]

According to the optical member inspection apparatus or holder of the present invention configured as described above, the optical member to be inspected can be
It can be held by a simple operation without touching the surface.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an optical member inspection apparatus according to an embodiment of the invention.

FIG. 2 is an enlarged vertical sectional view of the holder shown in FIG. 1;

FIG. 3 is a side view of the holder.

FIG. 4 is a plan view of a holder.

FIG. 5 is a bottom view of the holder.

FIG. 6 is an exploded plan view of the holder with a cover removed.

FIG. 7 is an exploded plan view of the holder at the time of attachment and detachment.

FIG. 8 is a side view of the holder at the time of attachment and detachment.

FIG. 9 is a longitudinal sectional view of a conventional holder.

[Explanation of symbols]

 2 Optical Member Holder 23 Holder 27 Inspection Optical Member 230 Main Body 230a Small Inside Diameter 230b Large Inside Diameter 234 Link Arm 236 Parallel Moving Plate 238 Movable Block 238a Movable Holding Surface 239 Stopper Pin 240 Fixed Spring Hook Pin 241 Movable Spring Hook Pin 242 Tension spring α, β Minimum diameter part

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Taichi Nakanishi 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd. (72) Takashi Higashihara 2-36-9 Maenocho, Itabashi-ku, Tokyo No. Asahi Kogaku Kogyo Co., Ltd. (72) Inventor Satoshi Nakamura 2-36-9 Maeno-cho, Itabashi-ku, Tokyo F-term in Asahi Kogaku Kogyo Co., Ltd. 2G086 EE08 FF01 FF04 2H044 AA03 AA04 AA14

Claims (7)

[Claims] 1. A holder for holding an optical member therein, the frame member abutting on a side surface of the optical member at at least two contact points, and the frame member movably toward each of the contact points. A movable member attached to the optical member and urged to contact the side surface of the optical member and press the optical member to each of the contact points. 2. The frame member is a tubular member that holds the optical member therein, and the inner surface has a radius substantially equal to the radius of the optical member only at the contact point. 2. The holder according to claim 1, wherein the diameter of the portion is larger than the radius of the optical member. 3. The frame member according to claim 1, wherein a portion facing each of the contact points across a space for holding the optical member is cut out to dispose the movable member. 2. The holder according to 2. 4. The holder according to claim 1, wherein the movable member is attached to the frame member via a link mechanism, and is urged toward the contact point by a spring. . 5. The holder according to claim 4, wherein said link mechanism comprises link members arranged in a parallelogram shape. 6. The holder according to claim 1, wherein a high friction member is attached to each of said contact points and a portion of said movable member which contacts said optical member. 7. An optical member inspection apparatus for irradiating an optical member with illumination light from one surface side and photographing from the other surface side to obtain image data used for inspection, wherein at least two contact points are provided. A frame member that abuts on the side surface of the optical member at a point, and is attached to the frame member movably toward each of the contact points, and abuts on the side surface of the optical member to bring the optical member into contact with each of the contact members. An optical member inspection apparatus, comprising: a holder including a movable member biased so as to press against a point.