JP2003185423A - Method and apparatus for measuring inclination angle of array-shaped angle face - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus wherein an array-shaped optical element having a plurality of arbitrary angle faces is used as an object to be measured, a measurement error due to a change in the posture of a measuring drive mechanism is removed, and the inclination angle of each angle face can be measured and evaluated with high accuracy and in a short time. <P>SOLUTION: The measuring method for the inclination angle of an array- shaped angle face is provided with a process in which interference fringes on one side face from among side faces forming a vertical angle in an array-shaped specimen having a plurality of inherent angle faces are obtained, and in which each inclination angle on the side face of the specimen with reference to a measuring optical angle is obtained on the basis of an analytical result of the interference fringes; and a process in which a relative inclination amount of each angle face arranged on the specimen is measured on the basis of the obtained angle face on each side face of the specimen. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for measuring a tilt angle of each angle surface of an optical element in which arbitrary angle surfaces are arranged in an array, and the tilt angle of each angle surface can be measured with higher accuracy and in a shorter time. It can be measured and evaluated.

[0002]

2. Description of the Related Art Conventionally, as a technique for measuring an angle formed by two surfaces of an optical element, there is one described in Japanese Patent Laid-Open No. 6-167325. This is a basic method of angle measurement using an autocollimator, in which an optical element is rotated by a rotating mechanism, and the absolute angle between two measured surfaces of the optical elements is obtained by using the principle of autocollimation. The apex angle is automatically measured. Moreover, what is described in JP-A-11-183148 is
An interference optical system is used for the purpose of removing the installation error of the object having an arbitrary angle surface, and the actual angle measurement of the apex angle is performed by an autocollimator placed facing each other as in the prior art. There is. Specifically, one of the two surfaces forming the apex angle of the test object is used as a reference surface and the other surface is used as a measurement surface, and the angle rotated by the rotating mechanism is corrected by the amount measured by the autocollimator. Is used. However, when measuring the apex angle of an array-shaped test object having a plurality of surfaces by the above conventional method, the posture of the test object must be changed for each apex angle. However, there is a problem that the measurement error becomes large,
There is also a problem that the measurement time becomes long because the respective apex angles cannot be measured at the same time.

[0003]

Therefore, in the present invention, an array optical element having a plurality of arbitrary angle surfaces is used as a measurement object,
It is an object of the present invention to eliminate a measurement error caused by a change in posture of a measurement drive mechanism so that the tilt angle of each angle surface can be measured and evaluated with higher accuracy and in a shorter time.

[0004]

[Measures taken to solve the problem]

SOLUTION 1 (Corresponding to Claim 1) Solution 1 is an array-shaped object having a plurality of unique angled surfaces, and one of the side surfaces forming an apex angle is interfered by an interference optical system. Obtaining the fringes, the step of obtaining the tilt angle of each side surface of the test object with respect to the measurement optical axis from the analysis result of the interference fringes, and the tilt angle of each side surface of the test object thus obtained are arranged on the test object. This is a tilt angle measuring method for arrayed angle surfaces, which measures the relative tilt amount of each angle surface.

As a result, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be measured with high accuracy and in a short time.

[0005]

SOLUTION 2 (corresponding to claim 2) Solution means 2 is an interference optical system having a transmission type reference plane plate, a holding means for an array-like object having a unique angle surface, and an array-like object. The tilt angle measuring device for an array of angled surfaces has a posture adjusting mechanism for an object and means for performing interference fringe analysis on each side face facing the interference optical system.

As a result, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be measured with high accuracy and in a short time.

[0006]

(Embodiment 1) (corresponding to claim 3) Embodiment 1 is the measuring method of the solving means 1, in which the step of rotating the test object by an angle substantially the same as the angle surface and the measurement of the other side surface are also performed. An array angle for measuring the relative tilt amount of each angle surface arranged on the test object from the obtained tilt angle of each side surface of the test object. This is the method of measuring the tilt angle of the surface.

[0007]

Embodiment 2 (corresponding to claim 4) Embodiment 2 is, in the measuring device of the solving means 2, rotating means having a rotating axis orthogonal to the measuring optical axis and rotating the rotating mechanism at an arbitrary angle, This means that a means for analyzing the interference fringes on each side facing the interference optical system before and after the rotation is provided.

[0008]

SOLUTION: The solution means 3 (corresponding to claim 5) is a standard optical block having substantially the same angle plane as an object to be measured in an angle plane tilt measurement of an array-shaped object having a unique angle surface. Using one of the side surfaces forming the apex angle, an interference optics is used to obtain interference fringes in the same field of view as the prototype optical block, and the analysis results of the interference fringes are used to determine the prototype optical block. A step of obtaining an inclination angle of the side surface of the object to be inspected with respect to the surface, a step of rotating the object object by an angle substantially the same as the angle surface, and a step of similarly obtaining an inclination angle of the other side surface with respect to the prototype optical block surface. And a tilt angle measuring method of an array-shaped angle surface, which measures relative tilting of each angle surface of the test object relative to the prototype optical block from the obtained tilt angle of each side surface of the test surface.

As a result, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be measured easily and accurately with reference to the prototype.

[0009]

SOLUTION 4 (corresponding to claim 6) The solution means 4 is an interference optical system having a transmission type reference plane plate, a holding means for an array-like object having a unique angle surface, and an array-like object. An attitude adjusting mechanism of an object, a rotating means having a rotation axis orthogonal to the measurement optical axis, and a prototype optical block having a surface substantially at the same angle as the object to be inspected are arranged, and the object to be inspected by the interference optical system An inclination angle measuring device for an array-shaped angle plane, characterized in that it has a processing means capable of detecting a prototype optical block within the same field of view and capable of individually analyzing interference fringes.

As a result, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be measured simply and highly accurately with reference to the prototype.

[0010]

(Embodiment 3) (corresponding to claim 7) Embodiment 3 is a solution means 1, a solution means 3 or a measurement method according to embodiment 1, which has a step of moving the array-shaped test object in the arrangement direction thereof. At the time of the movement, one or more side surfaces of the plurality of side surfaces of the test object to be detected within the same field of view are made to overlap, and the measurement results are connected by using the overlapping surfaces to perform array-shaped test. The tilt angle of each angle surface can be relatively detected over the entire surface of the object without causing a measurement error due to the change in posture due to the movement.

As a result, it becomes possible to measure the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces with high accuracy by correcting the error of the feed drive system.

[0011]

Embodiment 4 (corresponding to claim 8) Embodiment 4 is the solution device 2, the solution device 4 or the measuring device of embodiment 2, and a moving mechanism for moving the array-shaped test object in the arrangement direction thereof. Utilizing the overlapping planes detected in the same field of view,
And a processing means for correcting a measurement error due to a change in posture of the moving mechanism.

As a result, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be measured with high accuracy by correcting the error of the feed drive system.

[0012]

Fifth Embodiment (corresponding to claim 9) A fifth embodiment is the solving means 2, the solving means 4 or the measuring device according to the second embodiment, wherein the displacement detecting means detects a posture change of the moving mechanism of the object. The processing means for feeding back the displacement detection amount and correcting the measurement error due to the posture change is provided.

As a result, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be measured with high accuracy by correcting the error of the feed drive system.

[0013]

(Embodiment 6) (corresponding to claim 10) Embodiment 6 is the measuring device of Solving means 2, Claim 4 or Embodiment 2, Embodiment 4, and Embodiment 5 in which the transmission type reference plane in the interference optical system is used. That is, the calculation processing means for correcting the shape error of the face plate is provided.

As a result, it is possible to provide a device for correcting the shape error of the transmission type reference plane plate in the interference optical system and measuring the tilt angle of each angle plane in the array-shaped test object with higher accuracy.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic structure of an interferometer will be described with reference to FIG. A Fizeau interferometer is used in this embodiment. The laser light generated by the laser light source 11 passes through the microscope objective lens 12 and is then converted into parallel light by the collimator lens 14. The parallel light is split into the reference light reflected by the transmissive reference flat plate 17 and the irradiation light to the object 20 to be inspected. Further, the reflected light reflected on the surface after irradiating the test object 40 is transmitted through the transmissive reference flat plate 17 and returns to the same optical path. The reference light reflected by the transmissive reference plane plate 17 and the object light reflected by the object 40 are converged by the collimator lens 14, are branched in the orthogonal direction by the optical path branching unit 13, and enter the interference fringe detection unit 15. To do. The detected interference fringes are analyzed by the arithmetic processing means 16 to obtain a flat surface shape measurement result. The above is the basic configuration of the Fizeau interferometer 10.

The definition of the tilt angle, which is a measurement item, will be described with reference to FIGS. 1 and 2. Taking a prism array as an example,
A tilt angle α of each prism surface in the lateral direction (arrangement direction) is defined as a tilt angle α, and a tilt about the array axis X in FIG. 2 as a rotation center is defined as a tilt angle β.

A tilt angle measuring method will be described with reference to FIGS. Assuming that the inspection object 40 is an inspection object such as a right-angled prism, the angle surface is 90 degrees, and the angle surfaces are arranged in an array. Object 40
Is held by the object holding unit 30, and one side surface of the angle surface thereof is configured to face the optical axis of the Fizeau interferometer 10, that is, the measurement optical axis. Note that FIG. 4 is a side view of FIG. Next, the measurement procedure will be described by taking the case of the tilt angle α as an example. First, one side surface A of the object to be inspected 40 is arranged so as to face the measurement optical axis, and the reference light from the transmissive reference plane plate 17 and the reflected light from the side surface A are caused to interfere with each other to form an interference fringe. It is detected by the detection means 15 and analyzed by the arithmetic processing means 16 to obtain the plane shape of the side surface A. The plane shape of the side surface A obtained at this time includes the inclination with respect to the axis orthogonal to the measurement optical axis which is the attitude error of the side surface A, and the inclination is Zeru.
By the aberration analysis such as nike polynomial, X direction and Y in FIG.
It is possible to obtain them separately in the directions. The lower left side of FIG. 5 shows the obtained X-direction inclinations εa1 to εa4 of each side surface, and the relative tilt angle is calculated based on εa1 as in the lower right side of FIG.

The relative tilt angle, that is, the tilt angle of the angle plane having each side of A2, A3 and A4 with respect to the angle plane having the side A1 as its side surface. In short, when the position of the test object 40 is adjusted so that the inclination of the A1 plane becomes 0 (orthogonal to the measurement optical axis) as shown in FIG. 6, the inclination of the A2 plane in the X direction with respect to the adjacent P1 angle plane. The inclination angle α of the P2 angle plane is obtained. A similar approach can be applied to the case of the tilt angle β. That is, if the tilt in the Y direction in FIG. 5 is replaced and the Y direction tilt of the A2 plane with respect to the Y direction tilt of the A1 plane is multiplied by √2, P2 for the adjacent P1 angle plane is obtained.
The tilt angle β of the angle plane can be obtained.

Next, a second embodiment will be described with reference to FIGS. In this embodiment, the rotating mechanism 31 is provided in the above-described embodiment, and the object 40 is rotatable. The rotation angle is an angle corresponding to the nominal apex angle of the test object 40, and the rotation causes the side surface B to be arranged so as to face the measurement optical axis. Then, the same processing as that performed on the side surface A in the above description is performed to obtain the relative inclination angle εb of the side surface B.

Originally, if the apex angle of each angle surface of the object 40 is uniform, the inclination εa of the A2 surface with respect to the A1 surface and the inclination εb of the B2 surface with respect to the B1 surface are equal. The difference in the values must be different in the apex angle, and the plane tilt angle α of P2 with respect to P1 at that time is α = (εa + ε
b) / 2. The face tilt angle β can also be obtained in the same way.

Next, a third embodiment will be described with reference to FIGS. As in the first and second embodiments, reference numeral 10
Is a Fizeau interferometer, reference numeral 17 is a transmission type reference flat plate, reference numeral 30 is an object holding portion, and reference numeral 31 is a rotating mechanism as in the second embodiment. Reference numeral 20 is an object to be inspected, reference numeral 21 is a prototype block, the angle of which is known in advance. According to this configuration, the side surface of the prototype block 21 can be observed in the same field of view of the interference fringe detection means (not shown) of the Fizeau interferometer 10, and the above-mentioned first embodiment,
It is possible to consider what was considered based on the A1 or B1 surface in the second embodiment as a reference on the side of the prototype block.
10 and 11, a prism that is not in the form of an array is used as the test object, but a prism array having a plurality of angle planes can also be measured as the test object. The surface of the inspection object A in FIG. 11 is the inspection object A.
1, 2, A3, and the like, and the same applies to the surface B of the object to be inspected, and the surfaces of the individual objects of inspection (for example, A1 and B1) are made to face the actual block.

Next, a fourth embodiment will be described with reference to FIGS. In this embodiment, an optical element having many apex angles as shown in FIG. 12 is used as the test object 40, the test object holding unit 30 and a moving mechanism 32 for moving the test object 40 in the arrangement direction of the test object 40. And a rotating mechanism 31 that integrally rotates the moving mechanism 32.

In an object 40 having a large number of apexes as shown in the figure, in order to carry out an adjacency comparative evaluation of each apex angle, it is necessary to carry out an adjoining comparative evaluation of each side surface. A motion error (straightness) when the object 40 is fed by 32 has a great influence on the measurement accuracy. The present embodiment is for reducing the influence, and its principle is as follows, if explained based on FIG. The moving mechanism 32 allows the object 40 to be inspected from the visual field x to the visual field y.
, The visual field y includes a motion error of the moving mechanism 32 with respect to the visual field x, and the influence naturally appears in the analysis result of the interference fringes. Therefore, as shown in FIG. 13, the movement error amount can be grasped by feeding the test object 20 so that one surface (A4 surface in the drawing) of the plurality of side surfaces A is overlapped, Therefore, it is possible to perform the correction and reduce the influence.

That is, in the schematic diagram in the middle part of FIG.
Since the difference between the inclination angles εa4 and εa4 ′ of the side surface A4 is caused by the motion error of the moving mechanism 32, the analysis results εa5 ′ to εa7 ′ in the visual field y are corrected so as to eliminate the difference. By the correction, the measurement results from εa1 to εa7 as shown in the lower stage can be obtained. By performing the above processing, it is possible to measure the same face tilt angle as in the above-described embodiment.

In addition, the moving mechanism 3 is used without setting the overlapping measurement surface.
You may make it arrange | position the detection means for measuring the movement error (straightness) of 2 separately. In this way, since no duplicate measurement surface is required, even when a prism array having a plurality of apexes is used as the test object, the measurement can be performed in a short time.

Next, a fifth embodiment will be described with reference to FIG. In all the measurements using the interference optical system, the transmission type reference flat plate 17 actually has a shape error, and the error directly becomes a measurement error. That is, although the analysis result of the interference fringes detected in the visual field x in FIG. 14 includes the error (lower right), it is possible to obtain the accurate measurement result of each side surface by correcting the error. Therefore, it is possible to further improve the accuracy of the surface tilt angle measurement of the test object. As a highly accurate method of grasping the shape error of the transmission type reference flat plate, a three-sided alignment method using a Fizeau interferometer is known.

[0026]

According to the constitutions of claims 1 to 4, it becomes possible to measure the tilt angle of each angular surface of the array-shaped test object having a plurality of arbitrary angular surfaces with high accuracy and in a short time. . According to the fifth and sixth aspects, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces can be easily and accurately measured with reference to the prototype. It will be possible.

According to the structures of claims 7 to 9, the tilt angle of each angle surface of the array-shaped test object having a plurality of arbitrary angle surfaces is corrected with higher accuracy by correcting the error of the feed drive system. It becomes possible to measure.

According to the structure of claim 10, in order to correct the shape error of the transmission type reference plane plate in the interference optical system, the tilt angle of each angle plane in the array-shaped test object can be measured with higher accuracy. It will be possible.

[Brief description of drawings]

FIG. 1 is a tilt angle of each surface of a prism array in an array direction.

FIG. 2 is a tilt angle with the array axis of each surface of the prism array as the center of rotation.

FIG. 3 is a tilt angle measuring device according to a first embodiment of the present invention.

FIG. 4 is a side view of FIG.

FIG. 5 is a diagram showing the principle of Embodiment 1 of the present invention.

FIG. 6 is a diagram showing the principle of Embodiment 1 of the present invention.

FIG. 7 is a tilt angle measuring device according to a second embodiment of the present invention.

FIG. 8 is a side view of FIG. 7.

FIG. 9 is a diagram showing the principle of Embodiment 2 of the present invention.

FIG. 10 is a tilt angle measuring device according to a third embodiment of the present invention.

FIG. 11 is a diagram showing the principle of Embodiment 3 of the present invention.

FIG. 12 is a tilt angle measuring device according to a fourth embodiment of the present invention.

FIG. 13 is a diagram showing the principle of Embodiment 4 of the present invention.

FIG. 14 is a diagram showing the principle of Embodiment 5 of the present invention.

[Explanation of symbols]

10: Fizeau interferometer 11: Laser light source 12: Microscope objective lens 13: Optical path branching means 14: Collimator lens 15: Interference fringe detection means 16: arithmetic processing means 17: Transmission type reference flat plate 20, 40: Object 21: prototype block 30: Object holding unit 31: Rotation mechanism 32: moving mechanism

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA31 AA35 AA37 BB22 BB25                       CC21 DD06 EE05 FF52 FF61                       FF65 GG04 HH03 LL12 LL37                       LL46 PP12 PP13 PP24 QQ21                       QQ25 QQ28 RR07                 2G086 EE08

Claims (10)

[Claims] 1. In an array-shaped test object having a plurality of unique angle surfaces, one of the side surfaces forming the apex angle is obtained by an interference optical system, and the interference fringes are analyzed. Obtaining a tilt angle of each side surface of the object with respect to the measurement optical axis,
A tilt angle measuring method for an array-shaped angle surface, which measures a relative tilt amount of each angle surface arranged on the test object from the obtained tilt angle of each side surface of the test object. 2. An interference optical system having a transmissive reference plane plate,
An array of angled surfaces having a holding means for the arrayed object having a unique angle surface, a posture adjusting mechanism for the arrayed object, and means for performing interference fringe analysis on each side facing the interference optical system. Tilt angle measuring device. 3. The measuring method according to claim 1, wherein the step of rotating the test object by substantially the same angle as the angle plane and the step of similarly obtaining the respective inclination angles with respect to the measurement optical axis of the other side surface. The method of measuring the tilt angle of an array-shaped angle surface, wherein the relative tilt amount of each angle surface arranged on the test object is measured from the obtained tilt angle of each side surface of the test object. 4. The measuring device according to claim 2, wherein the rotation means has a rotation axis orthogonal to the measurement optical axis, and each side surface is rotated by the rotation mechanism at an arbitrary angle and faces the interference optical system before and after the rotation. A tilt angle measuring device for arrayed angle planes with a means for performing interference fringe analysis. 5. An angle plane tilt measurement of an array-shaped test object having a unique angle surface, wherein a prototype optical block having substantially the same angle surface as the test object is used to form a vertical angle. Interference fringes on one side surface of the prototype optical block in the same visual field as the prototype optical block, and from the analysis result of the interference fringes, the inclination angle of the side surface of the object with respect to the prototype optical block surface is obtained. And a step of rotating the test object by substantially the same angle as the angle plane, and a step of similarly obtaining an inclination angle with respect to the prototype optical block surface of the other side surface. A tilt angle measuring method for an array-shaped angle surface, which measures the tilt of each angle surface of a test object relative to the prototype optical block from the tilt angle. 6. An interference optical system having a transmission type reference plane plate,
An array-shaped object holding means having a unique angle surface, an attitude adjustment mechanism of the array-shaped object, a rotating means having a rotation axis orthogonal to the measurement optical axis, and an angle surface substantially the same as the object. And a processing unit capable of detecting the object to be inspected and the prototype optical block in the same field of view by the interference optical system, and capable of individually performing interference fringe analysis. A tilt angle measuring device for arrayed angled surfaces. 7. The measuring method according to claim 1, 3, or 5, further comprising a step of moving the array-shaped test object in the array direction, and detecting the same in the same field of view during the moving. One or more side surfaces of the plurality of side surfaces of the test object are made to overlap with each other, and the measurement results are connected by using the overlapping surfaces, and the posture changes due to the movement over the entire surface of the array-shaped test object. A tilt angle measuring method for an array-shaped angle surface, which is capable of relatively detecting the tilt angle of each angle surface without causing a measurement error. 8. The measuring apparatus according to claim 2, 4 or 6, wherein a moving mechanism for moving the array-shaped test object in the array direction and an overlapping surface detected in the same visual field are used. And a processing unit that corrects a measurement error caused by a change in the posture of the moving mechanism. 9. The displacement measuring device according to claim 2, 4, or 6, wherein the displacement detecting means detects a posture change of a moving mechanism that moves the array-shaped test object in the array direction, and a displacement detection amount. And a processing unit that corrects a measurement error due to a posture change by feeding back the angle. 10. The measuring device according to claim 2, claim 4, claim 6, claim 8 or claim 9, further comprising arithmetic processing means for correcting a shape error of a transmission type reference plane plate in the interference optical system. A tilt angle measuring device for an array-shaped angle surface, which is characterized in that