JP5025501B2 - Optical element holding mechanism and optical element measuring apparatus - Google Patents

Description

  The present invention relates to an optical element holding mechanism and an optical element measuring apparatus.

Conventionally, for example, in an optical element measuring device such as a wavefront aberration measuring device or a focal length measuring device, when starting measurement, the position and orientation of the subject are adjusted with respect to the measuring position and optical axis of the optical element measuring device. Need to be placed. For this reason, the optical element measuring apparatus includes an optical element holding mechanism that holds the optical element that is the subject so that the position of the optical element can be adjusted. Then, an adjustment jig such as a parallel plate is arranged on the holding part of the subject, and the amount of deviation of the posture of the holding part is measured using the reflected light of the adjustment jig, and the deviation amount is below the allowable range. In this way, the optical element holding mechanism is adjusted.
As an example of performing adjustment without using such an adjustment jig, there is a technique disclosed in Patent Document 1. In Patent Document 1, when measuring the wavefront aberration of a lens by an interferometer as an optical element measuring device, the lens tilt is corrected with respect to incident light parallel to the optical axis so that the tilt correction of the lens can be adjusted easily and quickly. The area outside the effective diameter of the first surface has a shape that returns reflected light parallel to the optical axis, and the flat portion of the area outside the effective diameter on the second surface of the lens is configured as a non-perpendicular surface with respect to the optical axis. It is described that a lens is used.
JP-A-8-334606

However, the conventional optical element holding mechanism and optical element measuring apparatus as described above have the following problems.
When adjustment is performed by placing an adjustment jig in the holding part of the subject as in the prior art, adjustment is performed by placing an adjustment jig instead of the subject, so that setup change is required and measurement is required. There is a problem that the efficiency of. In addition, even if the posture of the holding unit changes after the adjustment, the change cannot be detected, and therefore the measurement may be continued with the holding unit being deviated, and inaccurate measurement may be performed. is there.
On the other hand, in the technique described in Patent Document 1, since the tilt adjustment can be performed at the flat portion of the subject, it is efficient in that the replacement of the adjustment jig can be omitted, but the posture of the subject is highly accurate. In order to make the adjustment, it is necessary to provide a flat portion that is somewhat wide in order to observe the interference fringes. Therefore, there is a problem that it is difficult to reduce the size and cost of the subject.

  The present invention has been made in view of the above problems, and provides an optical element holding mechanism and an optical element measuring apparatus capable of easily and efficiently adjusting a holding posture even for a small subject. The purpose is to provide.

In order to solve the above problems, in the invention according to claim 1, an opening that transmits measurement light to the optical element that is the subject, and an outer peripheral portion of the subject that is provided around the opening are provided. An optical element holding mechanism having a subject holding portion that is held and positioned in the optical axis direction, and is provided on the radially outer side of the subject holding portion so as to be aligned in the same plane as the subject holding portion A detection plate holding portion, and an outer opening provided around the subject holding portion on the radially outer side of the subject holding portion and penetrating toward the incident direction side of the measurement light with respect to the posture detection plate holding portion; A detection plane capable of measuring interference fringes having light reflectivity, and the detection plane includes a posture detection plate disposed on the posture detection plate holding portion so as to cover the outer opening; To do.
According to the present invention, when light enters from the same direction as the measurement light on the radially outer side than the subject holding part, the light passes through the outer opening, reaches the detection plane of the posture detection plate, and the light enters. Reflected light traveling toward the direction is formed. By performing interference fringe observation using the reflected light, the posture of the posture detection plate holding unit can be detected. Therefore, even when the subject is held by the subject holding unit, it is possible to detect the posture of the subject holding unit that is on the same plane as the posture detection plate holding unit.

According to a second aspect of the present invention, in the optical element holding mechanism according to the first aspect, the posture detection plate is formed in an annular shape, and the optical element can be externally fitted at an annular inner peripheral portion. And
According to this invention, since the optical element is externally fitted by the inner peripheral portion of the attitude detection plate, the radial positioning member of the optical element can also be used, so that a simple configuration can be achieved.

According to a third aspect of the present invention, in the optical element holding mechanism according to the first or second aspect of the invention, the subject holding unit is configured such that the plane that holds the optical element sandwiches the recess and the periphery of the optical element. The configuration is arranged in the direction.
According to this invention, since the plane for holding the optical element of the subject holding portion is arranged in the circumferential direction of the optical element with the concave portion interposed therebetween, the area of the subject holding portion is increased by the area of the concave portion. It is possible to reduce the inclination of the optical element due to dust and the finished state of the processed surface.

According to a fourth aspect of the present invention, in the optical element holding mechanism according to any one of the first to third aspects, the posture detection plate has light permeability, and a back surface facing the detection plane is light diffusive. It is set as the structure which has.
According to the present invention, since the back surface of the posture detection plate facing the detection plane has light diffusibility, the light transmitted through the detection plane and reflected by the back surface is diffused, and the interference detection pattern is obtained when an interference fringe image is obtained. Since the light returning to the same optical path as the reflected light is reduced, it becomes easy to observe the interference fringes by the reflected light from the detection surface of the posture detection plate.

According to a fifth aspect of the present invention, in the optical element holding mechanism according to any one of the first to third aspects, the posture detection plate is light transmissive, and a back surface facing the detection plane is the detection plane. It is set as the structure inclined with respect to.
According to the present invention, since the back surface of the posture detection plate facing the detection plane is inclined with respect to the detection plane, light that passes through the detection plane and enters the back surface is reflected obliquely with respect to the incident direction. In addition, since the light returning to the same optical path as the reflected light on the detection plane is reduced when obtaining the interference fringe image, the interference fringe observation by the reflected light from the detection surface of the posture detection plate is facilitated.

The invention according to claim 6 is an optical element measuring apparatus that irradiates an optical element as a subject with measurement light and measures the optical element with the measurement light. An optical element holding mechanism according to any one of the above, a reference plane for detecting an inclination of the detection plane of the posture detection plate held by the posture detection plate holding portion of the optical element holding mechanism, and the optical element A light source unit that irradiates parallel light to the detection plane and the reference plane of the holding mechanism, and interference obtained by causing the reflected lights of the parallel light irradiated from the light source unit to the detection plane and the reference plane to interfere with each other An interference fringe observation unit configured to observe the amount of deviation of the attitude of the detection plane of the attitude detection plate with respect to the reference plane by the fringes.
According to the present invention, the detection plane with respect to the reference plane is obtained from the interference fringes obtained by irradiating the reference plane and the detection plane with parallel light from the light source unit and causing the interference fringe observation unit to interfere with the reflected light. The amount of misalignment can be observed. At this time, since the optical element holding mechanism according to claims 1 to 5 is provided, the posture of the subject holding unit can be detected in a state where the subject is held by the subject holding unit.

According to a seventh aspect of the present invention, in the optical element measurement apparatus according to the sixth aspect, the light source unit also serves as a light source that generates the measurement light.
According to the present invention, since the light source unit also serves as a light source that generates measurement light, it is possible to observe the deviation of the posture of the posture detection plate, that is, the subject holding unit, simultaneously with the optical element measurement using the measurement light. .
In the present invention, it is preferable that the reference plane also serves as a reference plane for generating a reference wavefront for measuring the optical element from the viewpoint of reducing the number of parts.

According to an eighth aspect of the present invention, in the optical element measuring apparatus according to the sixth or seventh aspect, the reflectance of the detection plane of the posture detection plate is substantially equal to the reflectance of the reference plane.
According to this invention, since the reflectance of the detection plane and the reflectance of the reference plane are substantially equal, the contrast of the interference fringes due to the respective reflected light is increased, and the posture can be detected with higher accuracy.

  According to the optical element holding mechanism and the optical element measuring apparatus of the present invention, the detection plane of the posture detection plate is arranged in the optical element holding mechanism so as to cover the outer opening provided on the radially outer side of the subject holding part. Thus, since posture detection can be performed, the holding posture can be adjusted easily and efficiently even for a small subject.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
The optical element holding mechanism according to the first embodiment of the present invention will be described together with an optical element measuring apparatus including the optical element holding mechanism.
FIG. 1 is a schematic configuration diagram showing a schematic configuration of the optical element measuring apparatus according to the first embodiment of the present invention. FIG. 2A is a schematic plan view showing an example of the shape of the subject of the optical element measuring apparatus according to the first embodiment of the present invention. FIG. 2B is a back view as viewed from A in FIG. FIG. 3 is a schematic perspective view showing a schematic configuration of the optical element holding mechanism according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view corresponding to the BB cross section of FIG. 3 when the subject is held by the optical element holding mechanism according to the first embodiment of the present invention.

The wavefront aberration measuring apparatus 100 of the present embodiment is an optical element measuring apparatus that measures the wavefront aberration of a test lens 5 (optical element) that is a subject.
As shown in FIG. 1, the schematic configuration of the wavefront aberration measuring apparatus 100 includes a light source unit 4, a half mirror 3, a holding mechanism 2 (optical element holding mechanism), a position adjusting mechanism 11, a reflecting mirror 7, a reference flat plate 8, and an imaging. The lens 9, the image sensor 10, and the computer 12 are included.

As shown in FIGS. 2A and 2B, the test lens 5 has a flange portion 5c having a circular outer shape, and a lens with a flange having lens surfaces 5a and 5b formed at the center thereof. It is. The flange portion 5c includes, on the lens surface 5a side, a receiving surface 5d formed as a plane orthogonal to the optical axis of the test lens 5 in order to position the test lens 5 in the optical axis direction.
As the shape and finish of the back surface 5e on the lens surface 5b side in the flange portion 5c, an appropriate shape and finish can be adopted. For example, it may be a flat surface parallel to the receiving surface 5d.
Further, the outer diameter of the flange portion 5c may be as small as possible as long as the area of the receiving surface 5d can be secured to the extent that the lens 5 can be positioned.
In the present embodiment, the lens surfaces 5a and 5b are illustrated in a biconvex lens shape assuming an aspheric lens used for an optical pickup or the like as an example, but the lens surfaces 5a and 5b may be It may be a spherical surface, and may have a concave surface or a flat surface.

The light source unit 4 generates coherent parallel light L to form interference fringes as measurement light for measuring the wavefront aberration of the lens 5 to be examined. As shown in FIG. 4a and a collimating lens 4b.
In the present embodiment, the parallel light L also serves as light for obtaining interference fringes for detecting the posture of the holding mechanism 2 and has a light beam diameter that can be applied to a range covering an outer opening 20b described later.
The half mirror 3 is disposed on the optical path of the parallel light L emitted from the light source unit 4, transmits about 50% of the parallel light L and travels straight, and reflects the other about 50% of the light sideways. It is an optical branching element.

The holding mechanism 2 holds the lens 5 to be tested on the optical axis of the parallel light L that passes through the half mirror 3, and includes a holding member 20 and a posture detection plate 21 as shown in FIG.
As shown in FIG. 1, the holding member 20 is, for example, a position adjustment mechanism 11 including a tilt table to which the holding member is attached and a mechanism for moving the table in a plane perpendicular to the optical axis direction and the optical axis. The position of the parallel light L in the direction of the optical axis and the position of the central opening 20a (described later) with respect to the optical axis and the posture such as the tilt are held.
The shape of the holding member 20 is provided in the center of the substantially disk-like member through a central opening 20a (opening) that is larger than the lens surface 5a of the lens 5 to be tested and smaller than the outer diameter of the flange 5c, A circular hole coaxial with the central opening 20a is provided on the outer side in the radial direction of the central opening 20a from the surface opposite to the light source part 4, and a flat holding surface 20c is formed at the bottom of the circular hole. Yes. The holding surface 20c is formed in a plane having flatness and surface accuracy so that the repeatability of the holding position of the receiving surface 5d of the lens 5 to be tested is good.
Outside the center opening 20a in the radial direction, outer openings 20b penetrating in the thickness direction of the holding member 20 are formed at four positions along the circumferential direction around the center opening 20a at an equal pitch. .
In the present embodiment, the radial position of the outer opening 20b does not overlap the flange 5c when the lens 5 to be tested is disposed in the center opening 20a, so that the parallel light L that passes through the half mirror 3 can enter. Is set to the correct position.
For example, a metal or the like can be used as the material of the holding member 20.

The posture detection plate 21 is a disc member that is larger than the inner diameter of the outer opening 20b. Of the detection surface 21a (detection plane) and the back surface 21b facing in the thickness direction of the posture detection plate 21, the detection surface 21a is a flat surface that is polished and finished with good surface accuracy, and reflects the parallel light L as reflected light L. ₁ is provided with light reflectivity. The detection surface 21a is preferably coated with a reflective film in order to improve the reflectance. However, if there is no problem in observation of interference fringes described later, the reflective film may not be applied.
As the material of the attitude detection plate 21, metal or glass can be employed.
When a glass plate is used as the posture detection plate 21, light diffusibility is imparted to the back surface 21b so that light transmitted through the detection surface 21a and reflected by the back surface 21b does not become interference fringe observation noise. Is preferred. For example, it is preferable to apply a rough surface processing such as a grained surface to the back surface 21b.

  Each posture detection plate 21 is held in a state where the detection surface 21a is in close contact with the holding surface 20c in the vicinity of the outer opening 20b so as to cover the outer opening 20b. As the holding means, an appropriate holding means can be adopted as long as the detection surface 21a can be brought into close contact with the holding surface 20c. For example, adhesion or a clamp (not shown) can be employed.

As described above, the holding surface 20c of the holding mechanism of the present embodiment includes the test lens holding unit 20A (subject holding unit) that holds the flange portion 5c of the test lens 5 in the vicinity of the center opening 20a, and the test subject. This is an example in which the posture detection plate holding portion 20B that holds the posture detection plate 21 in the vicinity of the outer opening 20b formed around the lens holding portion 20A is formed as a different region in the same plane. .
Therefore, the lens holding unit 20A and the posture detection plate holding unit 20B can be formed as the same processed surface. As a result, the processing accuracy is the same, and it can be formed as a plane aligned with high precision on the same plane.

The reflection mirror 7 is transmitted through the test lens 5, and then diffused after being condensed at the focal position of the test lens 5, is reflected by the reference surface 7 a, and travels backward on the same optical path, so that the half mirror 3. Above, interference fringes are formed.
However, in this embodiment, since the lens for optical pickup in which aberration correction is performed in a state including a medium such as an optical disk is used as the test lens 5, the test lens 5 is interposed between the test lens 5 and the reflection mirror 7. Further, a correction plate 6 corresponding to the light transmission part of the medium is arranged.
When the lens 5 to be tested is aberration corrected by a single lens, it is not necessary to use the correction plate 6.

The reference flat plate 8 is a flat plate member having light reflectivity arranged orthogonal to the parallel light L emitted from the light source unit 4 and reflected laterally by the half mirror 3. Thereby, the parallel light L reflected to the side by the half mirror 3 can be reflected on the same optical path as the reflected light L ₀ and returned to the half mirror 3 side.
The reflected light L ₀ is light that generates interference fringes with the reflected light L ₁ reflected by the detection surface 21 a of the posture detection plate 21. Therefore, the reference flat plate 8 is provided with a reference flat surface 8a made of a flat surface that is polished and has good surface accuracy on the half mirror 3 side. In the present embodiment, the reflectance of the reference plane 8 a is set to be substantially the same as the reflectance of the attitude detection plate 21.

The imaging lens 9 interferes with the reflected light L ₀ reflected by the reference plane 8 a and transmitted through the half mirror 3, and the light transmitted through the test lens 5, reflected by the reflective mirror 7, and retransmitted through the test lens 5. A fringe image is formed on the image sensor 10, and the reflected light L ₀ reflected by the reference flat plate 8 and transmitted through the half mirror 3 is incident on the half mirror 3 from the holding mechanism 2 side and transmitted through the half mirror 3. Then, an interference fringe image formed by the reflected light L ₁ that is reflected by the detection surface 21 a of the posture detection plate 21, reaches the half mirror 3 again, and is reflected by the half mirror 3 is formed on the image sensor 10. It is a lens to do.
The imaging element 10 photoelectrically converts each interference fringe image formed by the imaging lens 9 and sends it to the computer 12, and is composed of, for example, a CCD or CMOS element.

The computer 12 includes a computer main body 12a including a CPU, a memory, an input / output interface, an external storage device, a keyboard, and the like, and a display monitor 12b.
The computer main body 12a executes an arithmetic processing program to perform appropriate image processing such as noise removal on the image signal transmitted from the image sensor 10 and display each interference fringe image on the display monitor 12b. The interference fringe image within the lens effective diameter of the test lens 5 and the interference fringe image corresponding to the position of the outer opening 20b are separated, and the wavefront aberration of the test lens 5 is determined from the interference fringe image by the test lens 5. It is possible to perform measurement processing for calculating. Any known process may be employed for the measurement process of wavefront aberration measurement. For example, when the fringe scanning method is used, control for moving the reference flat plate 8 controlled to move by a control device (not shown) in the optical axis direction can be performed based on an algorithm of the fringe scanning method.
Moreover, the attitude | position of the holding mechanism 2 can be calculated from the interference fringe image corresponding to the position of the outer side opening part 20b as needed.

The operation of the wavefront aberration measuring apparatus 100 of the present invention will be described focusing on the attitude adjustment operation of the holding mechanism 2.
FIGS. 5A, 5 </ b> B, and 5 </ b> C are schematic diagrams illustrating examples of interference fringe images before and after posture adjustment, respectively.

  In order to measure the test lens 5 with the wavefront aberration measuring apparatus 100, first, the test lens 5 is held by the test lens holding unit 20 </ b> A of the holding mechanism 2. At this time, the receiving surface 5d of the flange portion 5c and the holding surface 20c of the holding mechanism 2 are arranged so as to be in close contact with each other at the lens holding portion 20A. Accordingly, the lens surface 5a of the lens 5 to be tested is held at the center of the central opening 20a in a state where the lens surface 5a faces the light source unit 4 side.

Next, the parallel light L is emitted from the light source unit 4.
When the parallel light L reaches the half mirror 3, approximately 50% of the light is transmitted and irradiated to the holding mechanism 2, through the central opening 20a to the lens 5 to be detected, and through each outer opening 20b to the detection surface 21a. To reach.
The light that has reached the test lens 5 and transmitted through the lens surface 5a passes through the lens surface 5b, proceeds while being condensed, forms an image at the focal position, proceeds after diffusing, and passes through the correction plate 6. The light reaches the reference surface 7a of the reflection mirror 7 and is reflected. The reflected light travels backward in the same optical path, passes through the lens surface 5b and the lens surface 5a, and is emitted as parallel light. Then, it reaches the half mirror 3 and is reflected to the imaging lens 9 side. Since the parallel light has an optical path difference corresponding to twice the transmitted wavefront aberration of the lens 5 to be examined, the parallel light is light that causes interference with the parallel light L. Therefore, an interference fringe image based on the wavefront aberration of the test lens 5 is formed on the image sensor 10 by the imaging lens 9.
The interference fringe image picked up by the image sensor 10 is displayed on the display monitor 12b of the computer 12 as an interference fringe 30A in the inner peripheral area of the central opening 20a (see FIG. 5A).
Further, the light reaching the sensing surface 21a is reflected as reflected light L ₁ at the detection surface 21a, and backward the same optical path to reach the half mirror 3, it is reflected to the imaging lens 9 side (FIG. 1 4).

On the other hand, of the parallel light L that has reached the half mirror 3 from the light source unit 4, the remaining about 50% of the light reflected laterally by the half mirror 3 reaches the reference plane 8 a of the reference flat plate 8 and is reflected. Then, the reflected light L ₀ travels backward in the same optical path, reaches the half mirror 3, and passes through the imaging lens 9 (see FIG. 1).
The reflected light L ₀ is transmitted through the half mirror 3 and then imaged on the image sensor 10 by the imaging lens 9. On the other hand, the reflected light L ₁ that passes through the half mirror 3, is reflected by the detection surface 21 a of the attitude detection plate 21, reaches the half mirror 3 again, and is reflected by the half mirror 3 is also the same as the reflected light L ₀ . The light travels along the optical path and is imaged on the image sensor 10 by the imaging lens 9.
Here, when the detection surface 21a is tilted with respect to the reference plane 8a, the reflected light L ₀ and L ₁ has a uniform optical path difference according to the tilt amount along the tilt direction. Therefore, the reflected lights L ₀ and L ₁ become light that causes interference on the combined optical path after being transmitted and reflected by the half mirror 3.
This interference fringe image is picked up by the image pickup device 10 and displayed on the display monitor 12b of the computer 12 as an interference fringe 31A in the area of the inner periphery of each outer opening 20b (see FIG. 5A).

  In the present embodiment, since the center opening 20a and each outer opening 20b are not in communication with each other in the radial direction of the center opening 20a, the images of the interference fringes 30A and 31A can be easily processed both visually and visually. It can be separated and observed.

Since the reference plane 8a and the detection surface 21a are polished planes having good surface accuracy, the interference fringes 31A reflect only the optical path difference due to the amount of inclination between them, and are parallel lines. It becomes an interference fringe image. From the direction and pitch of the parallel interference fringes and the wavelength of the parallel light L, the inclination direction and the inclination amount of the detection surface 21a with respect to the reference plane 8a can be calculated.
Therefore, for example, if the position adjustment mechanism 11 is configured to be automatically controllable by the computer main body 12a, the position adjustment mechanism 11 is driven according to the inclination direction and the inclination amount of the detection surface 21a calculated by the computer main body 12a. Thus, the posture of the holding member 20, that is, the posture of the detection surface 21a can be automatically adjusted to a posture corresponding to the reference plane 8a.

However, the measurer may adjust the posture of the detection surface 21a by manually operating the position adjustment mechanism 11 while viewing the interference fringe image displayed on the display monitor 12b of the computer 12. .
For example, when the interference fringes 31A are viewed, the position adjustment mechanism 11 is driven so that the interference fringes 31A are uniformly provided in the respective outer openings 20b and the intervals between the fringes are further widened. The posture can be adjusted to a posture corresponding to the reference plane 8a.
FIG. 5B shows, as an example, a state in which the interference fringe 31A has changed to an interference fringe 31B in which the interference fringe pitch is enlarged to such an extent that no fringes are seen at each outer opening 20b. Show.
At this time, in the present embodiment, since the center opening 20a and each outer opening 20b are not in communication with each other in the radial direction of the center opening 20a, a change from the interference fringe 31A to the interference fringe 31B Observation can be performed without being affected by the change from the fringe 30A to the interference fringe 30B.

The target value for posture adjustment can be appropriately set according to the necessity of measurement of the lens 5 to be measured. In this case, the target value of the interference fringe 31B for which adjustment is completed can be appropriately set according to the size and arrangement of the outer opening 20b.
For example, in FIG. 5B, an adjustment target value can be set such that the number of interference fringes observed at each outer opening 20b is “n or less (n is a natural number)”.

As described above, in the present embodiment, the half mirror 3, the imaging lens 9, the imaging device 10, and the computer 12 reflect the respective reflected lights of the parallel light L emitted from the light source unit 4 to the detection surface 21a and the reference plane 8a. An interference fringe observation unit configured to observe the amount of deviation of the attitude of the detection surface 21a with respect to the reference plane 8a is configured by the interference fringes 31A (31B) obtained by causing L ₁ and L ₀ to interfere with each other.

  Each detection surface 21a is in close contact with the posture detection plate holding unit 20B, and the posture detection plate holding unit 20B and the lens holding unit 20A are aligned on the same plane. This is the same as adjusting the posture of the lens holding portion 20A. Therefore, the position adjustment of the receiving surface 5d of the test lens 5 held by the test lens holding unit 20A is adjusted to a posture orthogonal to the measurement optical axis of the wavefront aberration measuring apparatus 100 by the posture adjustment. Become.

By such an attitude adjustment, as shown in FIG. 5B, an interference fringe 31B in which the error in the holding attitude of the lens 5 to be tested is reduced to an allowable value or less is obtained at the outer opening 20b.
Thereafter, the position adjustment mechanism 11 adjusts the position of the lens 5 to be measured in the optical axis direction and in the plane perpendicular to the optical axis via the holding mechanism 2, and as shown in FIG. The interference fringes 30C on the inner peripheral side of the portion 20a are set to almost zero state (null state). At this time, an interference fringe obtained at the outer opening 20b is referred to as an interference fringe 31C.
Based on the image of the interference fringe 30C, the wavefront aberration of the lens 5 to be measured is measured. That is, the interference fringes 30C imaged by the image sensor 10 are sent to the computer main body 12a, and a known wavefront shape measurement process is performed. Thereby, the wavefront aberration of the test lens 5 is measured.
At this time, images of the interference fringes 30C and the interference fringes 31C separated from the interference fringes 30C are sent to the computer main body 12a and can be displayed on the display monitor 12b.
Thereby, for example, when the posture of the holding mechanism 2 changes due to some disturbance, the measurer or the computer main body 12b detects the change in posture from the change in the image of the interference fringe 31C, and manually or as necessary. Posture adjustment can be performed automatically. Therefore, it is possible to perform measurement while holding the lens 5 in an appropriate posture at all times.

As described above, according to the holding mechanism 2 of the present embodiment, the outer opening 20b is provided on the outer side in the radial direction of the lens holding portion 20A, and the posture detection plate is provided on the posture detection plate holding portion 20B in the vicinity of the outer opening 20b. By holding 21, it is possible to detect the posture of the test lens holding portion 20A even when the test lens 5 is held by the test lens holding portion 20A.
Thereby, even during measurement, the posture of the lens 5 to be detected can always be detected, so that highly accurate wavefront aberration measurement can be performed.
Further, for example, as compared with the case where the posture adjustment of the test lens holding portion 20A is performed separately from the measurement of the test lens 5 by arranging a posture measuring jig instead of the test lens 5 as in the prior art. This eliminates the need for changeover from posture adjustment to wavefront aberration measurement, and enables efficient measurement.
Further, in the present embodiment, since the flange portion 5c of the test lens 5 is not used for posture adjustment, the flange portion 5c can be miniaturized within a range that can be held by the test lens holding portion 20A. Even the lens 5 to be tested can be adjusted in posture easily and with high accuracy. Further, general-purpose measurement that is not affected by the shape of the flange portion 5c of the lens 5 to be tested can be performed.

Next, a first modification of the present embodiment will be described.
FIG. 6 is a schematic partial plan view showing a schematic configuration of a holding mechanism according to a first modification of the first embodiment of the present invention.

  A holding mechanism 2A (optical element holding mechanism) according to this modification includes a posture detecting plate 22 having a shape and a size different from the posture detecting plate 21 of the holding mechanism 2 according to the first embodiment. Hereinafter, differences from the first embodiment and the first modification will be mainly described.

The posture detection plate 22 is a ring-shaped member that covers each outer opening 20b of the holding member 20, as shown in FIG. The inner diameter of the hole 22c of the posture detection plate 22 is larger than the outer diameter of the flange portion 5c of the lens 5 to be tested, and the outer diameter of the outer peripheral portion 22d of the posture detection plate 22 is smaller than the inner diameter of the side wall 20f of the holding member 20. It is set.
Moreover, the CC cross section in FIG. 6 becomes a cross section similar to FIG. That is, in the thickness direction, a detection surface 22a (detection plane) and a back surface 22b are provided, and the detection surface 22a is held in close contact with the holding surface 20c.
The material of the posture detection plate 22 can be the same material as the posture detection plate 21 of the first embodiment. Moreover, the detection surface 22a and the back surface 22b are each formed of a plane formed in the same manner as the detection surface 21a and the back surface 21b in the first embodiment, except that the outer shape is annular.

  According to this modification, since the posture detection plate 22 is made of an annular member, each outer opening 20b can be covered with one component, and the number of components can be reduced. In addition, the posture detection plate 22 can be easily arranged, assembled, and exchanged with respect to the holding member 20.

Next, a second modification of the present embodiment will be described.
FIG. 7 is a schematic partial plan view showing a schematic configuration of a holding mechanism according to a second modification of the first embodiment of the present invention.

The holding mechanism 2B (optical element holding mechanism) of the present modified example is different from the holding member 20 and the posture detection plate 21 of the holding mechanism 2 of the first embodiment, and holding members 23 and 23 having different shapes or sizes, respectively. The posture detection plate 22 of the first modified example is provided.
As shown in FIG. 7, the holding member 23 includes three outer openings 23 b instead of the four outer openings 20 b of the holding member 20 of the first embodiment. Hereinafter, differences from the first embodiment and the first modification will be mainly described.

The outer opening 23b has an arcuate hole extending so as to divide the circumferential direction into approximately three along the circumferential direction of the concentric circle of the central opening 20a on the radially outer side of the central opening 20a. To the surface 20d in the thickness direction.
And the attitude | position detection board 22 is hold | maintained so that each outer side opening part 23b may be covered on the holding surface 20c.
Moreover, the DD cross section in FIG. 7 becomes a cross section as shown in FIG.

According to this modification, the holding member 23, since an outer opening 23b is an arc-shaped through-holes, as compared with the first embodiment, the interference fringe image by the reflected light L ₁ of the sensing surface 22a Since observation can be performed in a wider range along the circumferential direction, posture adjustment is facilitated, and adjustment can be performed with higher accuracy.

Next, a third modification of the present embodiment will be described.
FIG. 8 is a schematic perspective view showing a schematic configuration of a holding member according to a third modification of the first embodiment of the present invention. FIG. 9 is a schematic partial plan view showing a schematic configuration of a holding mechanism according to a third modification of the first embodiment of the present invention. 10 is a cross-sectional view taken along line EE in FIG.

  A holding mechanism 2C (optical element holding mechanism) of the present modified example is different from the holding member 20 and the posture detection plate 21 of the holding mechanism 2 of the first embodiment, and holding members 24 and The posture detection plate 22 of the first modified example is provided.

  As shown in FIG. 8, the holding member 24 replaces the four outer openings 20b of the holding member 20 of the first embodiment with three outer openings 20b arranged equally in the circumferential direction, respectively. A recess 24e that is recessed from the holding surface 20c toward the surface 20d is provided in a region including the outer opening 20b (see FIG. 10). Hereinafter, differences from the first embodiment and the first modification will be mainly described.

As shown in FIG. 9, the three recesses 24 e of this modification have an arc shape larger than a semicircle projecting radially outward from an arc that divides the circumference of the center opening 20 a into approximately three equal parts, as shown in FIG. 9. Provided. For this reason, in this modification, the test lens holding portion 20A that holds the receiving surface 5d of the test lens 5 is separated from the outer side in the radial direction of the central opening 20a by the holding surface 20c being cut out by the three concave portions 24e. It is composed of three regions formed in a convex shape that sag inward in the radial direction.
Further, the posture detection plate holding portion 24B that holds the detection surface 22a of the posture detection plate 22 is also substantially divided into three along the concentric direction in which the outer opening 20b is aligned by the holding surface 20c being cut out by the three concave portions 24e. It is constituted by three plane areas.

According to the present modified example, the lens holding portion 24A and the posture detection plate holding portion 24B are formed by being divided into a plurality of locations separated in the circumferential direction by the concave portion 24e of the holding member 24, and therefore the holding surface 20c. Compared to the case where the lens is continuous in the circumferential direction, the areas of the lens holding unit 24A and the posture detection plate holding unit 24B are reduced, and the flatness of the holding surface 20c and dust are less affected. Therefore, the variation in how the receiving surface 5d of the lens 5 to be tested and the detection surface 22a of the posture detection plate 22 are in contact with the lens holding portion 24A and the posture detection plate holding portion 24B can be reduced and held with higher accuracy. it can.
In addition, the recess 24e becomes a machining clearance hole when the holding surface 20c is processed by removal processing, polishing processing, or the like, so that the processing area is reduced. Therefore, the recess 24e has a higher accuracy than the case without such a processing clearance hole. Can be easily performed.

Next, a fourth modification of the present embodiment will be described.
FIG. 11 is a schematic partial plan view showing a schematic configuration of a holding mechanism according to a fourth modification of the first embodiment of the present invention.

  A holding mechanism 2D (optical element holding mechanism) of the present modified example is different from the holding member 20 and the posture detection plate 21 of the holding mechanism 2 of the first embodiment, and holding members 40 and The posture detection plate 22 of the first modified example is provided.

  As shown in FIG. 11, the holding member 40 is obtained by replacing the central opening 20 a and the outer opening 20 b of the holding member 20 of the first embodiment with radial openings 41. Hereinafter, differences from the first embodiment and the first modification will be mainly described.

The radial opening 41 includes radial through-holes extending in three directions in a plan view penetrating from the holding surface 20c toward the surface 20d. That is, the three central inner peripheral surfaces 41a having the same diameter as the central opening 20a are arranged concentrically at the center, and the posture is directed radially outward from the circumferential end of the central inner peripheral surface 41a. An arcuate outer hole 41b larger than a semicircle projecting to the vicinity of the outer peripheral portion 22d of the detection plate 22 is provided, and a radial opening 41 is formed.
For this reason, the test lens holding portion 20A that holds the receiving surface 5d of the test lens 5 has the holding surface 20c cut out by the three outer hole portions 41b, and the radially inner side from the radially outer side of the central inner peripheral surface 41a. It is comprised by the area | region of 3 places formed in the convex shape which sags toward.
Further, the posture detection plate holding portion 20B that holds the detection surface 22a of the posture detection plate 22 has a holding surface 20c cut out by three outer hole portions 41b, and approximately divided into three adjacent directions of the outer hole portions 41b. It is constituted by three plane areas.

This modification is an example in which an opening that transmits measurement light to the lens 5 to be examined and an outer opening are integrated, and the inner side of the center inner peripheral surface 41a is an opening. A range where the outer hole 41b and the posture detection plate 22 overlap is an outer opening.
In this case, the interference fringe image output on the display monitor 12b is cut out only for the inside of the center inner peripheral surface 41a and the region of the outer hole 41b covered by the posture detection plate 22 for easy viewing. It is preferable to display only the interference fringes 30A (30B) and the interference fringes 31A (31B) by masking the images between them.

[Second Embodiment]
An optical element holding mechanism according to the second embodiment of the present invention will be described.
FIG. 12 is a schematic partial plan view showing a schematic configuration of the optical element holding mechanism according to the second embodiment of the present invention. 13 is a cross-sectional view taken along line FF in FIG.

The holding mechanism 2E (optical element holding mechanism) of the present embodiment includes the holding member 20 of the first embodiment and a posture detection plate 25 that is different from the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
As shown in FIGS. 12 and 13, the attitude detection plate 25 is an annular member that covers each outer opening 20 b of the holding member 20. The inner diameter of the hole 25c (annular inner peripheral portion) of the posture detection plate 25 is set to a diameter dimension for fitting the flange portion 5c of the lens 5 to be tested. In addition, the outer diameter of the outer peripheral portion 25 d of the posture detection plate 25 is a diameter dimension that is fitted into the side wall 20 f of the holding member 20.

In the thickness direction, as shown in FIG. 13, a detection surface 25a (detection plane) and a back surface 25b that face each other in parallel are provided, and the detection surface 25a is held in close contact with the holding surface 20c. For this reason, in this embodiment, the holding surface 20c is the posture detection plate holding portion 20B where the portion that is in close contact with the detection surface 25a, and the other portions are all the lens holding portion 20A.
As the material of the posture detection plate 25, the same material as that of the posture detection plate 21 of the first embodiment can be adopted. In addition, the detection surface 25a and the back surface 25b are each formed of a plane formed in the same manner as the detection surface 21a and the back surface 21b in the first embodiment, except that the outer shape is annular.
Therefore, by replacing the holding mechanism 2E with the wavefront aberration measuring apparatus 100 instead of the holding mechanism 2 of the first embodiment, the lens 5 to be measured is held as in the first embodiment, Even during measurement, the posture of the lens 5 to be detected can always be detected, so that it is possible to perform highly accurate wavefront aberration measurement.

Further, according to the holding mechanism 2E of the present embodiment, the posture detection plate 25 is closely attached to the holding surface 20c and positioned in the radial direction in a state of being fitted inside the side wall 20f of the holding member 20.
Since the flange portion 5c of the test lens 5 is fitted by the hole 25c of the posture detection plate 25, the posture detection plate 25 also serves as a positioning member in the radial direction of the test lens 5. Therefore, the positioning member for the lens 5 to be examined can be omitted, and the configuration can be simplified.

Next, a modification of this embodiment will be described.
FIG. 14 is a schematic partial cross-sectional view showing a schematic configuration of a holding mechanism according to a modification of the second embodiment of the present invention.

  A holding mechanism 2F (optical element holding mechanism) according to the present modification includes a posture detection plate 25A having a different shape instead of the posture detection plate 25 of the holding mechanism 2E of the second embodiment. Hereinafter, a description will be given focusing on differences from the second embodiment.

  The posture detection plate 25A includes an inclined surface 25f that is inclined so as to be non-parallel to the detection surface 25a, instead of the back surface 25b of the posture detection plate 25. This modification is particularly suitable when a material having optical transparency such as a glass plate is used as the material of the posture detection plate 25A.

According to the posture detection plate 25A, the incident light from the outer opening 20b is, when passing through the detection surface 25a, to be reflected in a direction different from the incident direction by the inclined surface 25f, the optical path mixed in reflected light L ₁ It is possible to prevent light having different differences from being observed.
Therefore, even if a glass plate or the like is used as the posture detection plate 25A, a good interference fringe image can be observed in the region of the outer opening 20b, and good posture adjustment can be performed.
Further, when the posture detection plate 25A is held on the holding surface 20c, the detection surface 25a can be securely held in close contact with the holding surface 20c without making a mistake.

In the above description, the example in which the outer openings 20b are provided at four places or three places has been described, but any number of the outer openings 20b may be provided as necessary.
For example, in the second modified example (FIG. 7) of the first embodiment, two adjacent outer openings 23b, 23b are made continuous to form one elongated outer opening, and the remaining outer openings 23b are replaced with each other. You may make it not form (namely, it is set as the filled state).

  In the above description, the posture detection plate is described as an example of a disk shape or an annular shape. However, the posture detection plate can be provided in a suitable shape according to the shape of the outer opening. For example, in the second modified example of the first embodiment, three arc-shaped members that cover the outer opening 23b may be used as the posture detection plate.

  Further, in the above description, the example in which the subject holding unit and the posture detection plate holding unit are on the same plane has been described. However, the subject holding unit and the posture detection plate holding unit have a parallelism processing accuracy. May be separate planes or protrusions aligned in the same plane, which are formed with different machining steps.

In the above description, the optical element measuring apparatus has been described as an example of the wavefront aberration measuring apparatus. However, any optical element measuring apparatus that performs measurement while holding an optical element as a subject may be used. It may be a device that performs measurement. For example, transmissive and reflective interferometers and focal length measuring devices can be used.
Further, depending on the type of the optical element measuring apparatus, a light source that generates measurement light may be provided in addition to the light source unit that performs posture adjustment.
Moreover, the optical element which is a subject of the optical element measuring apparatus is not limited to a lens. For example, optical elements such as a reflecting mirror having a curved surface or a plane, a prism, and a filter can be used.

  In the above description, the light source unit that irradiates the parallel light that irradiates each of the detection plane and the reference plane is described as an example in which the light source that generates the measurement light also serves as the light source that generates the measurement light. You may provide separately from a part.

In addition, the constituent elements described in the above embodiments and modifications can be implemented in appropriate combination within the scope of the technical idea of the present invention.
For example, the configuration in which the back surface is inclined with respect to the detection surface of the posture detection plate as in the modification of the second embodiment can be combined with any posture detection plate of the first embodiment.

It is a schematic block diagram which shows schematic structure of the optical element measuring device which concerns on the 1st Embodiment of this invention. FIG. 2 is a schematic plan view showing an example of the shape of a subject of the optical element measuring apparatus according to the first embodiment of the present invention, and a back view of the A view thereof. It is a typical perspective view which shows schematic structure of the optical element holding | maintenance mechanism which concerns on the 1st Embodiment of this invention. FIG. 5 is a cross-sectional view corresponding to a cross section taken along line BB in FIG. 3 when a subject is held by the optical element holding mechanism according to the first embodiment of the present invention. It is a schematic diagram which shows an example of the interference fringe image before attitude | position adjustment and after attitude | position adjustment. It is a typical fragmentary top view which shows schematic structure of the holding mechanism which concerns on the 1st modification of the 1st Embodiment of this invention. It is a typical fragmentary top view which shows schematic structure of the holding mechanism which concerns on the 2nd modification of the 1st Embodiment of this invention. It is a typical perspective view showing a schematic structure of a holding member concerning the 3rd modification of a 1st embodiment of the present invention. It is a typical fragmentary top view which shows schematic structure of the holding mechanism which concerns on the 3rd modification of the 1st Embodiment of this invention. It is EE sectional drawing in FIG. It is a typical fragmentary top view which shows schematic structure of the holding mechanism which concerns on the 4th modification of the 1st Embodiment of this invention. It is a typical fragmentary top view which shows schematic structure of the optical element holding | maintenance mechanism which concerns on the 2nd Embodiment of this invention. It is FF sectional drawing in FIG. It is a typical fragmentary sectional view showing a schematic structure of a maintenance mechanism concerning a modification of a 2nd embodiment of the present invention.

Explanation of symbols

2, 2A, 2B, 2C, 2D, 2E, 2F Holding mechanism (optical element holding mechanism)
3 Half mirror (interference fringe observation part)
4 Light source section 5 Test lens (test object, optical element)
5c Flange 5d Receiving surface 7 Reflecting mirror 7a Reference surface 8 Reference flat plate 8a Reference plane 9 Imaging lens (interference fringe observation unit)
10 Image sensor (interference fringe observation part)
11 Position adjustment mechanism 12 Computer (interference fringe observation part)
20, 23, 40 Holding member 20A Test lens holding part (subject holding part)
20B Posture detection plate holder 20a Center opening (opening)
20b, 23b Outer opening 20c Holding surface 20f Side walls 21, 22, 25, 25A Attitude detection plates 21a, 22a, 25a Detection surface (detection plane)
21b, 22b, 25b Back surface 22d, 25d Outer peripheral part 24e Recessed part 25c Hole (annular inner peripheral part)
25f Inclined surface 30B, 31B, 30C, 31C Interference fringe 41 Radial opening 41a Center inner peripheral surface (opening)
41b Outer hole (outer opening)
100 Wavefront aberration measuring apparatus L Parallel light (measurement light)
L ₀ , L ₁ reflected light

Claims (8)

An optical element having an opening that transmits measurement light to an optical element that is a subject, and a subject holding portion that is provided around the opening and holds the outer periphery of the subject and positions the subject in the optical axis direction. A holding mechanism,
A posture detection plate holding portion provided on the outer side in the radial direction of the subject holding portion and arranged in the same plane as the subject holding portion;
An outer opening provided around the subject holding portion on the radially outer side of the subject holding portion and penetrating in the incident direction side of the measurement light with respect to the posture detection plate holding portion;
It has a detection plane capable of measuring interference fringes having light reflectivity, and the detection plane includes a posture detection plate disposed on the posture detection plate holding portion so as to cover the outer opening. An optical element holding mechanism.   The optical element holding mechanism according to claim 1, wherein the posture detection plate is formed in an annular shape, and the optical element can be fitted on an annular inner peripheral portion.   3. The optical element holding mechanism according to claim 1, wherein the object holding portion is arranged in a circumferential direction of the optical element with a plane holding the optical element sandwiching a concave portion. 4.   The optical element holding mechanism according to any one of claims 1 to 3, wherein the posture detection plate has light permeability, and a back surface facing the detection plane has light diffusibility.   The optical element holding device according to any one of claims 1 to 3, wherein the posture detection plate is light transmissive, and a back surface facing the detection plane is inclined with respect to the detection plane. mechanism. An optical element measuring apparatus that irradiates an optical element as a subject with measurement light and measures the optical element with the measurement light,
The optical element holding mechanism according to any one of claims 1 to 5,
A reference plane for detecting an inclination of the detection plane of the posture detection plate held by the posture detection plate holding portion of the optical element holding mechanism;
A light source unit that emits parallel light to the detection plane and the reference plane of the optical element holding mechanism;
The amount of deviation of the posture of the detection plane of the posture detection plate with respect to the reference plane is determined by interference fringes obtained by causing the reflected light of the parallel light emitted from the light source unit to the detection plane and the reference plane to interfere with each other. An optical element measuring apparatus comprising an interference fringe observation unit that can be observed.   The optical element measurement apparatus according to claim 6, wherein the light source unit also serves as a light source that generates the measurement light.   The optical element measuring apparatus according to claim 6 or 7, wherein a reflectance of the detection plane of the posture detection plate is substantially equal to a reflectance of the reference plane.

Images