JPH11125510A - Interferometer and alignment method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interferometer which facilitates the alignment of a lens to be inspected even if a surface to be inspected deviates greatly in position and tilt and is a concave surface having a large radius of curvature. SOLUTION: The interferometer is equipped with an interferometer main body 111 equipped with a laser light source 101, which emits measurement light, a reference lens 112, which reflects part of the measurement light from the laser light source 101 to generate reference light, and the lens 115 to be inspected which generates light to be inspected by reflecting the measurement light passed through the reference lens 112 and generates interference fringes by interference between the reference light and light to be inspected to measure the surface shape, etc., of the lens 115 to be inspected; and a screen 136, which has a hole 136a is arranged between the reference lens 112 and lens 115 to be inspected, and the center of curvature of the lens 115 to be inspected is aligned with the optical axis of the reference lens 112 to pass the light to be inspected through the hole 136, thereby aligning the lens 115 to be inspected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an interferometer for measuring a surface shape and the like of an object to be measured using a laser beam, and an alignment method in the interferometer.

[0002]

2. Description of the Related Art Conventionally, an interferometer has been put into practical use as a measuring device for measuring the shape of a lens or the like. For example, an interferometer as shown in FIG. 5 disclosed in Japanese Patent Application Laid-Open No. 8-128804 is known. Have been.

In the configuration of the interferometer shown in FIG. 5, for example, coherent light emitted from a He-Ne laser light source 211 having a wavelength of 633 nm passes through a lens 212 to become a divergent light beam, and enters a polarization beam splitter 213. . The light beam transmitted through the polarizing beam splitter 213 is transmitted through the quarter-wave plate 214, becomes parallel light by the collimator lens 215, and enters the reference lens 216.

A part of the light beam incident on the reference lens 216 is reflected by the reference surface 216a of the reference lens 216,
The remaining light flux passes through the reference lens 216 and passes through the test lens 2.
Reach 17

[0005] The light beam reflected by the reference surface 216a is:
As a reference light beam, the optical path is reversed and the collimator lens 2
The light passes through the 15,1 / 4 wavelength plate 214 and enters the polarization beam splitter 213. The incident light beam has its optical path bent at the polarization reflection surface 213a of the polarization beam splitter 213, and is condensed on a screen 218 provided at the focal position 215a of the collimator lens 215, so that the light spot 218a of the reference light forms an image. Is done.

On the other hand, the luminous flux reaching the lens 217 to be inspected is
The light reflected by the test surface 217a of the test lens 217 reverses the optical path as a test light flux, and the light path is bent by the polarization reflection surface 213a of the polarization beam splitter 213 as in the case described above, and the focal position 215a of the collimator lens 215 Is focused on the screen 218 installed in the camera, and the light spot of the test light flux is imaged.

However, for example, when the center of the radius of curvature of the test surface 217b does not coincide with the optical axis of the collimator lens 215, that is, the test surface 217 shown by a broken line in FIG.
The position of the center of the radius of curvature as shown in FIG.
In the case where the light beam is shifted from the optical axis No. 15, the light spot of the test light flux is separated from the position of the light spot 218a of the reference light in FIG.
An image is formed as a light spot 218b of the test light beam at a position as shown in FIG.

Therefore, when observing interference fringes, the center of curvature of the reference surface 216a and the center of curvature of the test surface 217a do not substantially coincide with the optical axis of the collimator lens 215, that is, for example, the test surface 217a. Is the center of curvature of
If not installed at a position that coincides with the optical axis of the collimator lens 215, such as the center of curvature b, the interval between the interference fringes becomes extremely small, and the interference fringes cannot be observed.

That is, it is necessary to adjust the optical path B of the test light beam reflected by the test surface 217b to match the light path A of the reflected light beam reflected by the reference surface 216a. In addition, when the test surface 217a is greatly inclined with respect to the optical axis, the amount of light reflected from the test surface 217a decreases, so that light spots and interference fringes are difficult to see.

For this reason, the light spots 218a and 21
8b to the alignment optical system 219, CCD element 221
While observing with, the inclination and position of the reference surface 216a and the test surface 217b are adjusted (hereinafter, this adjustment is referred to as “alignment”) so as to coincide with the optical axis of the collimator lens 215.

After the alignment is performed by the alignment optical system 219, the alignment optical system 21 is used for observing interference fringes.
Only 9 is switched to the interference fringe observation optical system 220. Thereby, interference fringes can be observed, and the shape of the test surface 217b can be understood.

[0012]

As described above, conventionally, alignment of the test surface 217b is performed while observing the light spot of the test light beam condensed on the screen 218. In this case, When the inclination of the test surface 217b and the positional deviation of the center of curvature with respect to the optical axis of the collimator lens 215 are large, the light spot 218b on the screen 218
Becomes dark and cannot be observed, and furthermore, the light spot 218b of the test light beam deviates from the screen 218 and becomes unobservable, and the inclination and the direction of the positional shift of the test surface 217b become unknown, so that the test lens 217 There is a problem that alignment is difficult because the arrangement state is not known.

Generally, as the radius of curvature of the surface 217a increases, the NA (numerical aperture) of the surface 217a decreases. Therefore, when the radius of curvature of the test surface 217a increases, the amount of the test light beam reflected by the test surface 217a decreases, and the light spot of the test light beam becomes dark. Here, when the test surface 217a is a convex surface, since the distance between the reference surface 216a and the test surface 217a is short, it is easy to visually recognize the positional deviation of the test surface 217a.

When the test surface 217a is concave, the distance from the reference surface 216a is long, and it is difficult to recognize the positional deviation of the test surface 217a. That is, as the surface 217a to be measured is concave and the radius of curvature is larger, the alignment becomes more difficult.

The present invention has been made in view of the above-mentioned conventional problems, and can be easily applied even when the position and inclination of the surface to be inspected are largely displaced or the surface to be inspected is a concave surface having a large radius of curvature. It is an object of the present invention to provide an interferometer and an interferometer alignment method capable of confirming an arrangement state of an inspection lens and aligning a lens to be inspected.

[0016]

According to the first aspect of the present invention,
An interferometer body having a light source for emitting the measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source. In an interferometer that generates interference fringes due to interference between the test light generated by reflection and the reference light, and measures the surface shape and the like of the test lens, the interference light is emitted from the interferometer main body and irradiated to the test lens. A thin light beam that coincides with the optical axis of the measurement light to be emitted is emitted from the main body of the interferometer.

According to the present invention, when the test lens attached to the interferometer is irradiated with a thin light beam coincident with the optical axis of the measurement light, the center of curvature of the test surface of the test lens becomes When on the optical axis, the reflected light can be easily confirmed as a bright spot on the screen in the main body of the interferometer. Accordingly, it is confirmed by the thin light beam that the arrangement state of the test lens is in a general alignment state.

According to a second aspect of the present invention, there is provided an interferometer main body having a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source. In an interferometer that generates interference fringes due to interference between the test light and the reference light, which are generated by the measurement light transmitted through the lens reflected by the test lens, and measures the surface shape and the like of the test lens, Between the reference lens and the test lens, there is a hole that allows the passage of the measurement light in a state that matches the optical axis of the reference lens, the optical axis of the test light from the optical axis of the reference lens An alignment assisting means for visually recognizing the test light when it is displaced is provided detachably.

According to the present invention, between the reference lens and the test lens, there is provided an alignment assist which allows the user to visually recognize the test light according to the state in which the optical axis of the test lens deviates from the optical axis of the reference lens. When the alignment of the test lens is performed, the arrangement of the test lens can be adjusted while visually observing the test light from the test lens by the alignment assisting means. Even when the position and the inclination of the surface to be measured are largely shifted or when the surface to be detected is a concave surface having a large radius of curvature, the alignment of the lens to be tested can be easily performed by a simple operation.

According to a third aspect of the present invention, there is provided an interferometer body having a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source. In an interferometer that generates interference fringes due to interference between the test light and the reference light, which are generated by the measurement light transmitted through the lens reflected by the test lens, and measures the surface shape and the like of the test lens, The interferometer body emits thin visible light whose optical axis coincides with the optical axis of the measurement light, and between the reference lens and the test lens, the test object in a state where the optical axis matches the optical axis of the reference lens. An alignment assisting device having a hole through which the reflected visible light from the lens can pass is provided.

According to the present invention, the alignment assisting means having the hole through which the thin visible light can pass through in the state of being coincident with the optical axis of the reference lens is provided between the reference lens and the test lens. If the arrangement of the test lens is not appropriate, fine visible light will be reflected and illuminated by the test lens on the alignment assisting means, so that the reflected light of the fine visible light passes through the hole. By adjusting the arrangement of the test lens as described above, even if the position and inclination of the test surface of the test lens are largely displaced, or the test surface is a concave surface having a large radius of curvature, Alignment can be performed with good workability.

According to a fourth aspect of the present invention, the reference light obtained by reflecting a part of the measurement light from the interferometer main body by the reference lens and the measurement light transmitted through the reference lens are reflected by the test lens. In an alignment method in an interferometer for generating an interference fringe due to interference with a test light and measuring a surface shape or the like of the test lens, a hole through which fine light can pass is provided between the reference lens and the test lens. A screen is arranged, and thin visible light is emitted from the interferometer main body toward the test lens through the hole of the screen in a state of being aligned with the optical axis of the reference lens, and the thin visible light is reflected by the test lens. The alignment of the test lens is performed by utilizing the presence or absence of light transmission through the hole of the screen.

According to the alignment method of the present invention, the screen having the hole through which the fine light can pass is disposed between the reference lens and the test lens, and the thin visible light reflected by the test lens. The alignment of the lens to be inspected is performed by utilizing the presence or absence of transmission through the hole of the screen. Therefore, when the arrangement of the lens to be inspected is not appropriate, the reflected light of the thin visible light from the lens to be inspected is illuminated on the screen. Similarly, by adjusting the arrangement of the test lens so that the reflected light of the thin visible light from the test lens passes through the hole, the position and inclination of the test surface of the test lens are largely displaced or Even when the test surface is a concave surface having a large radius of curvature, an alignment method capable of executing the alignment of the test lens with good workability can be provided.

[0024]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows a conceptual diagram of an interferometer according to an embodiment of the present invention. This interferometer is used to measure a test lens 4 to be measured.
Interferometer body 1 provided with a laser light source for emitting measurement light for measuring the shape of the surface 4a to be inspected, and interferometer body 1
A reference lens 2 arranged in the optical path of the measurement light emitted from the light source, and an alignment aid having a hole 5a through which a thin light beam 3 described later also arranged in the optical path of the measurement light emitted from the interferometer body 1 passes And a screen 5 as a means.

Further, from the interferometer main body 1, a thin light beam 3 which is visible light and coincides with the optical axis of the measurement light can be emitted.

The screen 5 is provided on the main body 1 of the interferometer.
Is disposed between the reference lens 2 and the test lens 4 attached to the interferometer so as to be visible from outside. The measuring light may be either visible light or invisible light.

In the interferometer shown in FIG. 1, the measurement light emitted from the interferometer main body 1 is partially reflected by the reference surface 2a of the reference lens 2 and goes back into the interferometer main body 1. The measurement light transmitted through the reference lens 2 is emitted toward the surface 4a of the lens 4 to be measured.

Here, when adjusting the approximate position of the surface 4a to be measured with respect to the measuring light, a thin light beam 3 which coincides with the optical axis of the measuring light is emitted from the interferometer body 1 and passes through the hole 5a of the screen 5. Let it. The thin light beam passing through this hole 5a is
The light is reflected by the surface 4a to be reflected and becomes reflected light. When the center of curvature of the surface 4a is substantially on the optical axis, the reflected light is transmitted through the hole 5a.
Since there is no bright spot due to irradiation on the screen 5 because the light passes through the screen 5, it is confirmed that the arrangement state of the lens 4 to be inspected is in a substantially aligned state, but the center of curvature of the surface 4a to be inspected is shifted from the optical axis. In this case, without passing through the hole 5a,
The light is irradiated onto the screen 5 surrounding the hole 5a.

Therefore, in order to make the arrangement of the lens 4 to be roughly aligned, the thin light beam 3 comes to the center of the surface 4a to be detected, that is, the reflected light from the surface 4a passes through the hole 5a of the screen. The approximate alignment of the test surface 4a is visually performed while tilting the test lens 4 with respect to the optical axis or moving the test lens 4 in the vertical direction so as to pass through. In addition, since it is observed whether or not the reflected light of the thin light beam 3 from the test surface 4 a is irradiated on the screen 5, the arrangement position of the screen 5 is between the reference lens 2 and the test lens 4. If so, the confirmation work is possible.

When the test surface 4a of the test lens 4 has a spherical surface with a large radius of curvature, a flat surface, or a shape close to a flat surface, light reflected from the test surface 4a passes through the hole 5a of the screen 5. By adjusting so as to pass through and return to the interferometer main body 1, that is, while reflecting the reflected light that is reflected on the test surface 4 a and irradiating the screen 5, the approximate inclination and the center of curvature of the test surface 4 a are determined. By adjusting the position, rough alignment of the test surface 4a can be easily performed visually.

In FIG. 1, when the measuring light is visible light, when the center of curvature of the surface 4a is displaced from the optical axis, a visible measuring light beam reflected on the surface 4a is measured. Is also illuminated on the screen 5 around the hole 5a without passing through the hole 5a.
The visual alignment of the test surface 4a is visually confirmed by visually recognizing the center of the visible measurement light beam reflected by the test surface 4a so as to pass through the center of the hole 5a. I can do it.

By the above operation, it can be set so that the measurement light beam from the surface 4a to be measured passes through the reference lens 2 and returns to the interferometer main body 1. This facilitates accurate alignment of the test surface 4a. Screen 5 for alignment
When the measurement light is shielded, the screen 5 is removed from between the reference lens 2 and the test lens 4 so as not to hinder the interference fringe measurement. The thin light beam 3
If the measurement light is visible light, a part of the measurement light can be used.If the measurement light is invisible light, a light source for visible light that is separate from the light source of this measurement light can be used as the main body of the interferometer. 1 to obtain visible light. When the measurement light is invisible light, a light receiving element connected to a monitor screen and having a hole in the center is used as the screen 5, and the surface of the light receiving element is irradiated with the measurement light beam from the surface 4a to be measured. If the presence / absence is configured to be visually recognized on the monitor screen, even when the measurement light is invisible light, the adjustment can be executed in the same manner as the visual adjustment of the thin light beam 3.

[First Embodiment] (Structure) FIG. 2 shows a first embodiment of the present invention. As shown in FIG. 2, a reference lens 112 having a reference surface 112a mounted in a lens barrel (not shown) is attached to a side surface of the interferometer main body 111 according to the first embodiment.

The interferometer body 111 has a laser light source 101 (for example, a He-Ne laser light source for visible light laser) for emitting laser light, and a beam composed of a combination of a concave lens and a convex lens for expanding the diameter of the laser light. An expander 102, a lens 103 that once converges the laser light that has passed through the beam expander 102 at a converging point and then diverges the light, and a lens 103 that converges the laser light condensed by the lens 103. The arranged pinhole 104, the mirror 105 and the mirror 1 for bending the divergent laser beam
07, a beam splitter 106 disposed between the mirror 105 and the mirror 107, a collimator lens 108 for converting the laser beam reflected by the mirror 107 into parallel light, and disposed on an optical path of light reflected from the beam splitter 106. CCD camera 110 and the collimator lens 108
And an alignment optical system 109 including a lens 109b for forming an image of the screen 109a on the CCD camera 110.

Although not shown, the interference fringes of the reference surface 112a of the reference lens 112 and the test surface 115a of the test lens 115 due to the respective reflected light are detected by the CCD camera 11 as shown in FIG.
An interference fringe observation optical system that forms an image at 0 is provided in parallel with the alignment optical system 109 so as to be switchable.

Further, the interferometer body 111 has an alignment light source (for example, He-Ne) for emitting a thin light beam of visible light.
A laser light source) 113, and a half mirror 114 that reflects a light beam from the alignment light source 113 (hereinafter, referred to as an “alignment light beam”) toward the reference lens 112 and the test lens 115 so as to match the optical axis of the collimator lens 108. Is arranged.

A screen 136 having a hole 136a through which the laser light transmitted through the reference lens 112 passes is provided.
It is arranged at the condensing position of the laser beam transmitted through the reference lens 112.

This screen 136 is used for the interferometer main body 11.
1 and at a position visible on the optical axis of the collimator lens 108. This screen 13
The light-collecting position 6 is determined by the reference lens 112, and thus may be formed integrally with the lens frame of the reference lens 112. It may be configured to be adjustable. The test lens 115 is disposed via a lens barrel on a lens frame (not shown) and a well-known moving table whose position can be adjusted in X, Y, Z, and θ directions in front of the screen 136.

(Operation) In the interferometer having the above configuration,
First, the reference lens 112 is aligned with the interferometer main body 111. In this case, the alignment light source 113
Is turned off, and the test lens 115 is removed from the interferometer.

In this state, the diameter of the laser light emitted from the laser light source 101 is enlarged by the beam expander 102 and becomes divergent light after being condensed by the lens 103. At this time, noise light of the laser light is cut by the pinhole 104. Pinhole 10
4 is transmitted through the beam splitter 106 and the half mirror 114, is further bent by the mirror 107, and is further bent by the mirror 105.
The light is collimated by the collimator lens 108 and emitted from the interferometer main body 111.

The laser light emitted from the interferometer main body 111 is partially reflected by the reference surface 112a of the reference lens 112, and this reflected light travels backward in the optical path.
And becomes reference light. The reference light is converged by the collimator lens 108, is bent by the mirror 107, passes through the half mirror 114, is reflected by the beam splitter 106, and is focused on the screen 109 a of the alignment optical system 109. The focal point at this time is C
Observed by the CD camera 110, the focal point is the interferometer body 1.
The reference surface 112a of the reference lens 112 is aligned so as to coincide with the optical axis of No. 11.

At this time, as described above, the test lens 115
Is not attached to the interferometer.
The alignment of the reference lens 112 is performed in a state where there is no reflection from.

Next, alignment with respect to the lens to be tested 115 is performed. In this case, the measurement light laser light source 101 is turned off, the test lens 115 is attached to the interferometer, and the alignment light source 113 is turned on when aligning the test surface 115a of the test lens 115.

The alignment light, which is visible light, emitted from the alignment light source 113 is reflected by the half mirror 114 and is bent by the mirror 107 to form a collimator lens 108, a reference lens 112, and a screen 136.
Through the hole 136a, and is reflected by the lens 115 to be measured.

At this time, if the position and inclination of the test surface 115a are small, the reflected light is transmitted through the hole 1 of the screen 136.
36a, goes backward and passes through the half mirror 114 and the beam splitter 106 to the alignment optical system 1.
Since light spots (bright spots) at which all the alignment light beams arrive are formed as thin light beams on the screen 109a of No. 09, it is confirmed that the rough alignment of the test surface 115a does not need to be further performed. That means
The assistance by the screen 136 is not required. However, if the test surface 115a is displaced or inclined,
The reflected light is irradiated on a screen 136 as an alignment light as shown by an arrow in FIG. By observing this state, it is visually determined that alignment of the test surface 115a is necessary. For this alignment ray,
The lens 1 to be inspected is set so that the center of curvature and the inclination of the surface to be inspected 115a substantially match visually, that is, the reflected light of the alignment light passes through the hole 136a of the screen 136.
Adjust the position of No.15. Thus, the rough alignment of the test surface 115a is completed. After that, the alignment light source 113 is turned off.

Next, when the laser light source 101 is turned on,
The measurement light emitted from the laser light source 101 and transmitted through the reference surface 112a is reflected by the test surface 115a,
12 and returns to the interferometer main body 111 to become a test light flux. This test light beam is converged on the screen 109a of the alignment optical system 109 like the reference light. This converging point is observed by the CCD camera 110 and the interferometer body 11 is observed.
An accurate alignment of the test surface 115a is performed so as to coincide with the first optical axis. Note that accurate alignment of the test surface 115a can be performed even when the alignment light source 113 is on.

When the alignment of the reference surface 112a and the test surface 115a is completed, the alignment optical system 1
09 is switched to an interference fringe observation optical system (not shown), the interference fringes are observed, and the shape of the test surface 115a is measured.

(Effects) According to the first embodiment, the alignment surface 113a, the half mirror 114, and the screen 136 are added to the conventional interferometer, so that the surface In addition, the alignment can be performed by a simple operation.

In the first embodiment, a He-Ne laser light source of a visible light laser is used as the laser light source 101.
The laser light source 1 is used when the test lens 115 is aligned.
Since the laser light from No. 01 is not used, the present invention is not limited to this, and the present invention can be implemented using a CO2 laser light source of an invisible laser.

[Second Embodiment] (Configuration) FIG. 3 shows a second embodiment of the present invention. The interferometer according to the second embodiment has basically the same configuration as the interferometer according to the first embodiment shown in FIG. 2, but the interferometer according to the second embodiment has, as shown in FIG. A laser light source (for example, He-Ne) for irradiating a visible light laser in the interferometer main body 120.
It is characterized in that a diverging optical system 121 for expanding the diameter of the laser light from the laser light source 101 is provided in front of the (laser light source) 101.

The diverging optical system 121 is connected to the laser light source 10.
It is arranged so as to be able to be inserted into and removed from the optical path of the laser light emitted from 1. Further, the diverging optical system 121 includes a beam expander 102 including a combination of a concave lens and a convex lens for expanding the diameter of the laser beam, and a beam expander 102.
A lens 103 that once converges the laser light that has passed through at the converging point and then diverges the light, and a pinhole 104 that is disposed at the position of the converging point of the laser light condensed by the lens 103. doing.

The interferometer according to the second embodiment has a configuration in which the alignment light source 113 in the first embodiment is omitted. Other configurations are the same as those of the first embodiment, and a detailed description thereof will be omitted.

(Operation) In the interferometer according to the second embodiment, the test lens 115 having a large inclination and a large positional deviation of the center of curvature with respect to the optical axis of the collimator lens 108.
The case where the test surface 115a is aligned will be described. In this case, the diverging optical system 121 is separated to a position where laser light from the laser light source 101 does not enter.

That is, the diverging optical system 121 is retracted to a position off the optical axis of the laser light source 101. This allows
The optical path of the laser light from the laser light source 101 is bent by a mirror 105 as a thin beam light, passes through a beam splitter 106, is bent by a mirror 107, passes through a collimator lens 108 and a reference lens 112, and passes through an interferometer main body 120. From the hole 13 of the screen 136
6a.

The laser light, which is thin visible light, is reflected on the surface to be measured 115a as an alignment beam, and
If the position of the lens 15a is shifted or tilted, the lens 1 to be inspected is moved so that the reflected light passes through the hole 136a of the screen 136.
By adjusting the position and the inclination of the reference numeral 15, rough alignment of the test surface 115 a is performed.

Next, the diverging optical system 121 is inserted into a predetermined position facing the optical path of the laser light emitted from the laser light source 101, and the inclination and the positional deviation of the center of curvature with respect to the optical axis of the collimator lens 108 are reduced. In the extremely small state, alignment is performed in the same manner as a conventional interferometer.

Thus, the reference surface 1 of the reference lens 112
Accurate alignment of 12a and the test surface 115a of the test lens 115 becomes possible. Then, after the alignment is completed, the shape of the test surface 115a can be measured by switching to the interference fringe observation optical system.

(Effect) According to the second embodiment, there is an advantage that a simple alignment can be performed without adding a new optical component to the conventional interferometer.

Third Embodiment (Structure) FIG. 4 shows a third embodiment of the present invention. The basic configuration of the interferometer shown in FIG. 4 is the same as that of the interferometer of the first embodiment shown in FIG.
A beam splitter 131 that splits the laser light emitted from the laser light source 101 into two beams is arranged at the previous stage, and the mirror 1 that reflects the laser light transmitted through the beam splitter 131 toward the beam expander 102.
32, a mirror 134 is disposed between the pinhole 104 and the beam splitter 106, and a mirror 133 is provided for reflecting light split by the beam splitter 131 to the mirror 134 side. .

The mirror 134 is rotatable about a rotation shaft 135, and is transmitted through the pinhole 104 and a position 134a where the thin beam reflected by the mirror 133 is reflected toward the beam splitter 106. The position 134b where the divergent light enters the beam splitter 106
And can be moved to. Other configurations are the same as those of the first embodiment, and a detailed description thereof will be omitted.

(Operation) In the interferometer having the above configuration,
When aligning the test surface 115a of the test lens 115, the mirror 134 is turned around the rotation shaft 135 as a support shaft to be at the position 134a. Thereby, the laser light source 10
1 and reflected by the beam splitter 131, the laser beam reflected by the mirrors 133 and
4, the light is transmitted through the beam splitter 106, reflected by the mirror 107, transmitted through the collimator lens 108 and the reference lens 112, and emitted from the interferometer body 130.

The surface to be inspected 115 is generated by the thin laser light.
If there is a position shift or inclination at a, adjustment is made so that the reflected light from the lens to be tested 115 passes through the hole 136a of the screen 136, and rough alignment of the surface to be measured 115a is performed.

Next, the mirror 134 is rotated around the rotation shaft 135 to move to the position 134b. As a result, the laser light emitted from the laser light source 101 and transmitted through the beam splitter 131 is bent by the mirror 132, transmitted through the beam expander 102, the condenser lens 103 and the pinhole 104, and becomes divergent light. Head in the direction of.

This laser beam enables accurate alignment of the reference surface 112a and the test surface 115a. Then, after the alignment is completed, the shape of the test surface 115a can be measured by switching to the interference fringe observation optical system.

(Operation) According to the third embodiment, since the member to be moved is only the mirror 134, there is an advantage that the moving mechanism can be simplified. 2, 3 and 4 for explaining the first, second and third embodiments,
Although a quarter-wave plate is not shown and described between the beam splitter and the collimator lens, it is a matter of course that these may be arranged similarly to the conventional example.

According to the present invention described above, the following configuration can be added. (1) An interferometer main body provided with a light source that emits measurement light, and a reference lens that reflects a part of the measurement light from the light source to generate reference light, and receives the measurement light transmitted through the reference lens. In an interferometer that generates interference fringes due to interference between the test light generated by reflection from the test lens and the reference light and measures the surface shape or the like of the test lens, the interferometer measures a distance between the reference lens and the test lens. And a screen having a hole through which the test light from the test lens can pass when the center of curvature of the test lens coincides with the optical axis of the reference lens. . According to this configuration, when the arrangement of the test lens is not appropriate, the test light from the test lens is irradiated onto the screen, so that the test light passes through the hole. By adjusting the arrangement of the lens to be inspected, even if the position and inclination of the surface to be inspected of the lens to be inspected are largely displaced or the surface to be inspected is a concave surface having a large radius of curvature, the alignment of the lens to be inspected can be adjusted. Can be executed with good workability.

(2) An interferometer main body provided with a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source, and a measurement transmitted through the reference lens In an interferometer that generates interference fringes due to interference between test light generated by reflection of a test lens and the reference light and measures the surface shape and the like of the test lens, the reference lens and the test lens A screen having a hole through which the test light from the test lens in a state where the center of curvature of the test lens arranged between the test lens and the reference lens coincides with the optical axis,
An interferometer, comprising: an alignment light source that emits a thin visible light beam from an interferometer body coaxially with the measurement light from the laser light source. According to this configuration, the same operation and effect as in the case of Appendix 1 can be exerted by using the alignment light source, and a light source that emits invisible light is used as a laser light source that emits the measurement light. Can be.

(3) An interferometer main body provided with a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source, and measuring the light transmitted through the reference lens. In an interferometer that generates interference fringes due to interference between test light generated by reflection of a test lens and the reference light and measures the surface shape and the like of the test lens, the reference lens and the test lens A screen having a hole through which the test light from the test lens in a state where the center of curvature of the test lens arranged between the test lens and the reference lens coincides with the optical axis,
An alignment light source that emits a thin light beam of visible light from the interferometer body coaxially with the measurement light from the laser light source, an alignment optical system that collects the reference light, and a reference light that is collected by the alignment optical system. And a CCD camera for observing, aligning the test lens while visually observing the irradiation light on the screen of the test light that reflects the thin light beam from the alignment light source by the test lens, and emits the light from the laser light source. An interferometer that performs alignment of the reference lens while observing, with a CCD camera, reference light reflected by the reference lens and collected by an alignment optical system. According to this configuration, alignment of both the reference lens and the test lens can be performed with good workability.

(4) An interferometer main body provided with a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source, and measuring the light transmitted through the reference lens. In an interferometer that generates interference fringes due to interference between test light generated by reflection of a test lens and the reference light and measures the surface shape and the like of the test lens, the reference lens and the test lens A screen having a hole through which the test light from the test lens can pass through in a state where the center of curvature of the test lens arranged between the laser light source and the optical axis of the test lens matches the optical axis of the reference lens; An alignment light source that emits a thin light beam of visible light from the interferometer body coaxially with the measurement light,
An alignment optical system for condensing the reference light, and a CCD for observing the reference light condensed by the alignment optical system
A camera, and aligns the test lens while visually observing the irradiation of the test light reflected by the test lens with the thin light beam from the alignment light source to the screen. The second test light reflected by the inspection lens and collected by the alignment optical system is denoted by C
An interferometer characterized by re-aligning a test lens while observing with a CD camera. According to this configuration, the outline and accurate alignment of the test lens with respect to the reference lens can be executed with good workability.

(5) An interferometer main body provided with a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source, and measuring the light transmitted through the reference lens. In an interferometer that generates interference fringes due to interference between the test light generated by reflection of light on the test lens and the reference light, and measures the surface shape and the like of the test lens, light is generated by the interferometer body. The arrangement of the test lens disposed between the reference lens and the test lens, between the reference lens and the test lens, while emitting thin visible light whose axis coincides with the optical axis of the measurement light. An interferometer comprising an alignment assisting means for visually recognizing a test light according to a state. According to this configuration, the alignment assisting means for visually recognizing the test light according to the arrangement state of the test lens is provided between the reference lens and the test lens. When performing the test, the position of the test lens can be adjusted while visually observing the test light from the test lens by the alignment assisting means. Even when the surface to be inspected is a concave surface having a large radius of curvature, the alignment of the lens to be inspected can be performed with good workability.

[0072]

According to the first aspect of the present invention, it is possible to easily confirm whether or not the center of curvature of the test surface of the test lens is substantially on the optical axis of the measuring light of the test surface. An interferometer can be provided.

According to the second aspect of the present invention, when the alignment of the test lens is performed, the alignment of the test lens can be adjusted while visually observing the test light from the test lens by the alignment assisting means. Even if the position and inclination of the test surface of the test lens are largely displaced or the test surface is a concave surface having a large radius of curvature, alignment of the test lens can be easily performed by a simple operation. Can be provided.

According to the third aspect of the present invention, the position and inclination of the test surface of the test lens are largely shifted by adjusting the arrangement of the test lens so that the test light passes through the hole. Also, it is possible to provide an interferometer capable of executing the alignment of the test lens with good workability even when the test surface is a concave surface having a large radius of curvature.

According to the fourth aspect of the present invention, even when the position and inclination of the test surface of the test lens in the interferometer are largely displaced, or when the test surface is a concave surface having a large radius of curvature, this test object can be obtained. It is possible to provide an alignment method capable of executing the alignment operation of the inspection lens with good workability.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an interferometer according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an optical system of the interferometer according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an optical system of an interferometer according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an optical system of an interferometer according to a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of an optical system of a conventional interferometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interferometer main body 2 Reference lens 2a Reference surface 3 Light beam 4 Test lens 4a Test surface 5 Screen 5a Hole 101 Laser light source 102 Beam expander 103 Lens 104 Pinhole 105 Mirror 106 Beam splitter 107 Mirror 108 Collimator lens 109 Alignment optical system 110 CCD camera 111 Interferometer body 112 Reference lens 113 Alignment light source 115 Test lens 136 Screen 136a Hole

Claims (4)

[Claims] 1. An interferometer main body including a light source that emits measurement light, and a reference lens that generates a reference light by reflecting a part of the measurement light from the light source, and the measurement light transmitted through the reference lens. In the interferometer, which generates interference fringes due to interference between the test light generated by reflection from the test lens and the reference light to measure the surface shape and the like of the test lens, the interferometer is emitted from the interferometer main body. An interferometer which emits a thin light beam, which coincides with the optical axis of measurement light emitted to an inspection lens, from an interferometer main body. 2. An interferometer main body including a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source, and the measurement light transmitted through the reference lens. In the interferometer for measuring the surface shape and the like of the test lens by generating interference fringes due to the interference between the test light and the reference light generated by reflection from the test lens, the reference lens and the test lens A hole through which measurement light in a state in which the reference lens coincides with the optical axis is provided, and when the optical axis of the test light deviates from the optical axis of the reference lens, the test An interferometer, wherein an alignment assisting means for making light visible is detachably provided. 3. An interferometer main body including a light source for emitting measurement light, and a reference lens for generating a reference light by reflecting a part of the measurement light from the light source, and the measurement light transmitted through the reference lens. In the interferometer that generates interference fringes due to interference between the test light generated by reflection from the test lens and the reference light and measures the image shape and the like of the test lens, the optical axis is adjusted by the interferometer body. Emitting thin visible light that coincides with the optical axis of the measurement light, and between the reference lens and the test lens, the visible light from the test lens in a state that matches the optical axis of the reference lens. An interferometer comprising an alignment assisting unit having a hole through which reflected light can pass. 4. Interference between reference light obtained by reflecting a part of the measurement light from the interferometer body by a reference lens and test light obtained by reflecting the measurement light transmitted through the reference lens by the test lens. In an alignment method in an interferometer for generating an interference fringe and measuring a surface shape or the like of a test lens, a screen having a hole through which fine light can pass is arranged between the reference lens and the test lens, From the main body of the interferometer, the thin visible light is emitted toward the test lens through the hole of the screen while being aligned with the optical axis of the reference lens, and the transmission of the fine visible light through the hole of the screen by the test lens is performed. An alignment method for an interferometer, wherein alignment of the test lens is performed using presence or absence.