KR20140131099A - Multi-interference phase interferometer with simultaneous measurement functions - Google Patents

Abstract

The present invention relates to an interferometer and, more particularly, to an interferometer with a function of simultaneous measuring multi-interference phases, which can perform precise and accurate measurement with a simple structure by simultaneously forming images of multiple interference patterns with a different phase from one another on a surface shape of an optical component without an additional transfer unit for moving a reference mirror, by including a beam splitter that emits beams with multiple phases differences to the front side of a condensing lens positioned inside the interferometer. The interferometer comprises a light source, a light enlarger, a condensing lens (objective lens), a collimation lens, a reference mirror, a test mirror, a rotating diffuser disk, a mirror, an image forming lens, a transmissivity variable filter, an image separating unit, and a charge-coupled device (CCD). A beam splitter is formed at one side of the condensing lens in order to split a beam radiated from the condensing lens or a pin hole into multiple beams. Thus, the beam radiated from the reference mirror can proceed not in parallel but at four different transmitting and receiving angles or more in order to enter the reference mirror or the test mirror. Therefore, the interferometer can simultaneously measure multiple interference patterns due to phase differences among the beams which are transmitted or received at different angles from one another.

Description

[0001] The present invention relates to an interferometer having simultaneous multi-

In particular, the present invention relates to an interferometer, and in particular, to an interferometer that includes a light splitting means for diverging a light beam emitted in front of a condenser lens located inside an interferometer so as to have a plurality of phase differences, The present invention relates to an interferometer having a multi-interference phase simultaneous measurement function capable of performing precise and accurate measurement with a simple structure by allowing multiple interference fringes having different phase differences with respect to a surface shape of a component to be simultaneously imaged.

In general, in order to measure the degree of the surface of an optical component manufactured at the time of manufacturing an optical component that forms a plane or a spherical surface, an interferometer (a light source divided into two divided light beams is referred to as a reference plane (or a curved surface) And the other branched light reflects from the optical surface to be measured. When the two lights meet again, the wavefront reflected from the optical surface to be measured is made to have an interference pattern due to a path difference with the wavefront reflected from the reference plane. A mechanism for measuring the shape error of the optical surface is used).

The most basic form of such an interferometer is the Twyman-Green interferometer, which is an interferometer in which two interfering samples are orthogonal to each other.

In addition to the basic type of interferometer, there is a Fizeau interferometer in which two interfering objects are located on the same optical axis, and the plane accuracy of the plane or spherical lens is measured.

1, a light beam emitted from a light source 101 is enlarged into parallel light through a beam expander 102, and then incident on an objective lens (not shown) 103, and focuses on a pin hole 104, which is a spatial filter.

The pin hole 104 serves to make a complete spherical wave. The complete spherical wave produced by the pinhole 104 is passed through a beam splitter 105 and passed through a collimation lens 106 and then transmitted as parallel light.

The parallel light is reflected from a reference spherical surface 107 and a test spherical surface 108, respectively.

The reflected waves of the two spherical surfaces interfere with each other to form an interference fringe. The interference fringes are incident on the collimator lens 106, reflected by the optical splitter 105 at 90 degrees, and imaged onto a rotating diffuser disk 109.

The rotation diffusion filter 109 removes the spark to obtain a clean interference fringe image.

The interference fringes imaged on the rotation diffusion filter 109 pass through the imaging lens 111 and a Graded ND Filter Disk 112 that controls the amount of light incident on the camera, As shown in FIG.

At this time, the interference fringes appearing through the camera 113 are generally circular or linear, as shown in Table 1, according to the degree of alignment between the reference spherical surface 107 and the test spherical surface 108.

Then, the interval between the two interference fringes is? / 2 (where? Is the wavelength of the laser light source)

With defocus

With Defocus and Tilt
If you have a tilt

On the other hand, a piezoelectric effect element (a piezoelectric effect element, which generates a voltage when a mechanical stress is applied and a device which uses a piezoelectric ceramics or the like to cause a distortion when a voltage is applied inversely, When the distance between the reference spherical surface 107 and the test spherical surface 108 is changed by moving the reference spherical surface 107 by a small amount using the probe 110, A pattern is obtained. At this time, 0 ° and 360 ° are the same interference pattern.

0 °

90 °
180 °
270 DEG
360 °

That is, since the amount of movement of the reference spherical surface 107 is? / 2 from 0 ° to 360 °,? / 8 is obtained for 90 °,? / 4 for 180 °, and 3λ / 8 for 270 ° , And in the case of 360 °, the image is equal to 0 ° as? / 2.

When the phase is not changed, for example, when there is only one image of 0 DEG, the surface shape information can be detected with respect to the ring displayed in black. However, since information can not be detected in the white part, Is to move the black ring to the white part.

Although four phases are described in Table 2, it is needless to say that more information can be obtained by further subdividing the phase.

1, the position of the reference lens is changed by using the piezoelectric element. As a result, the distance between the reference surface (the last surface of the reference lens) and the test surface changes (the position of the reference lens focus changes) To obtain interference patterns of several phases.

2, the light beam emitted from the light source 201 is expanded into parallel light through a beam expander 202, and then incident on a polarized beam splitter (PBS) Transmitted and reflected through the reference plane 204 and the test plane 205, respectively.

In this process, the reference plane 204 is moved to the piezoelectric element to measure the phase information of the different interference fringes.

However, the interferometer shown in FIGS. 1 and 2 has a problem in that accurate information can not be obtained when the reference plane is moved by the piezoelectric element because the interference pattern is affected by the flow of convection while the movable face is moving.

To solve this problem, as shown in FIG. 3, a phase-difference Twyman-Green interferometer called a 4D interferometer has the same structure as that of FIG. 2 but differs in a camera section.

As shown in FIGS. 3 and 4, a device for changing the phase in front of each pixel of the camera portion so as to simultaneously measure four phase images (interference fringes) at the same time is formed of a wire grid And acquire images of different phases from each other.

However, such an interferometer requires a plurality of wire grid elements corresponding to the number of phases to be acquired, which complicates the construction and increases manufacturing costs.

In addition, such a conventional interferometer requires not only a piezoelectric element for moving a reference plane, but also a separate structure for changing (changing) the phase as in the case of a plurality of wire grid elements, There is a problem that can not be done.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above. An object of the present invention is to provide a light-dividing means having a simple structure which is easy to fabricate and can exhibit high performance, To thereby obtain the shape information of the surface of the optical component in a single measurement quickly, accurately, and easily, thereby providing an interferometer having a simultaneous multi-interference phase measurement function.

It is another object of the present invention to provide a simple structure without adopting a separate structure required for phase shift (change), thereby eliminating the measurement error of the interferometer, reducing the total volume, And an interferometer having a function of simultaneously measuring a multi-interfering phase.

According to an aspect of the present invention, there is provided an optical system including a light source, a light expander, a condenser lens (objective lens), a light separator, a collimator lens, a reference spherical surface, And a charge coupled device (CCD), wherein a light splitting means for splitting a light beam emitted from the condenser lens or the pin hole into a plurality of light beams is formed on one side of the condenser lens, Four or more interference fringes according to the phase difference of each ray diverging and converging at different angles are measured at the same time so as to be incident on the reference spherical surface or the test spherical surface by proceeding at four or more divergent and convergent angles .

Wherein the image separating means comprises any one of a CGH hologram, a pyramid prism or a lens having an enlargement magnification, and the light splitting means is any one of a pinhole having a plurality of holes, a hologram element, a birefringent crystal, a semitransparent mirror, .

When the light splitting means is formed of a pinhole, a semi-transmission mirror or an optical fiber, since four or more light beams traveling in different directions have different spatial positions to be respectively formed, four or more images are easily acquired in a charge coupled device Wherein the image separating means uses a pyramidal prism or a lens having an enlargement magnification.

Wherein the pinhole is formed at a front point formed by the condenser lens so that at least four holes are formed so that the proceeding light ray has four or more different phase differences and each hole has a phase difference, And is inclined to vary the distance with respect to the collimating lens.

The birefringent crystal is provided with a first crystal and a second crystal. The second crystal is provided at an angle rotated by 45 degrees with respect to the first crystal to produce a ray having multiple divergent angles by the birefringence component of the crystal, As shown in FIG.

The transflective mirror is formed of a first reflective surface, a second reflective surface, a third reflective surface, and a fourth reflective surface.

The optical fiber is formed so that four or more optical fibers are bundled, one end of the optical fiber is positioned at a focal point of the condenser lens, and the other end of the optical fiber is formed such that the optical fibers are mutually different in length, And is formed so as to spread out at other spatial positions.

The hologram element is characterized in that the light beams transmitted through the hologram element are incident on the collimator lens at different divergent angles.

The image separating means made of the pyramidal prism is characterized in that four or more images are divided into the charge coupled device (CCD) by reflection or refraction.

The image separating means made up of the pyramidal prism uses four charge coupled devices (CCDs) for separating and imaging four or more images by reflection, and when four or more images are separated and formed by refraction, And one charge coupled device (CCD) is used.

INDUSTRIAL APPLICABILITY As described above, the present invention has the effect of obtaining surface information of an optical component accurately, quickly, and easily at a simple and low cost.

Further, in order to obtain multiple phase-shifted interference fringes, a plurality of interference fringes are obtained at a time by dividing a plurality of interference fringes into a plurality of light beams by using divergent and converging means of a simple structure without complicated components, And the measurement result can be easily obtained.

1 is a schematic view showing a basic structure of a conventional interferometer.
2 is a schematic view showing a structure of a conventional Twiamann green interferometer.
FIG. 3 is a diagram schematically showing the structure of a phase-chirp Twyman-Green interferometer called a 4D interferometer.
4 is a view schematically showing a structure of a conventional interferometer showing the principle of enlarging each pixel and simultaneously measuring images of four phases at the same time as an image of the camera part of Fig. 3
FIG. 5 is an interferometer having a multi-interference phase simultaneous measurement function according to a preferred embodiment of the present invention, in which pinholes having different spatial positions in which four or more rays are respectively formed are formed as light dividing means, In which a plurality of light beams are refracted using a plurality of light-receiving elements to divide and acquire a plurality of images into one charge-coupled device.
FIG. 6 is a view schematically showing a state in which a plurality of light beams are reflected by the image separating means made up of the pyramid-shaped prism of FIG. 5 to divide and acquire an image into four charge coupled devices, respectively.
7 is an interferometer having a multi-interference-phase simultaneous measurement function according to a preferred embodiment of the present invention. The hologram element defocused while a light beam propagates along an optical axis is formed as a light splitting means, and an image separating means comprising a CGH hologram In which a plurality of images are divided and acquired by one charge-coupled device.
FIG. 8 is an interferometer having a multi-interference phase simultaneous measurement function according to a preferred embodiment of the present invention. The interferometer includes a birefringent crystal in which a ray is defocused while proceeding along an optical axis, as a light splitting means, In which a plurality of images are divided and acquired by one charge-coupled device.
9 is an interferometer having a multi-interference-phase simultaneous measurement function according to a preferred embodiment of the present invention. The interferometer includes a semi-transparent mirror that is defocused while a light beam propagates along an optical axis, And FIG. 5 is a diagram schematically showing a state in which a plurality of images are divided and acquired in four charge coupled devices using a means.
10 is an interferometer having a function of simultaneously measuring multi-interfering phases according to a preferred embodiment of the present invention. The interferometer has a function of dividing an optical fiber in which spatial positions where four or more rays are respectively formed are different from each other, In which a plurality of light beams are refracted to obtain a plurality of images on one charge coupled device.
11 is a view schematically showing a state in which a plurality of light beams are reflected by the image separating means made up of the pyramidal prism of FIG. 10 to divide and acquire an image into four charge coupled devices, respectively.
12 is a view schematically showing a state in which a plurality of lasers, which are light sources, are formed with different wavelengths so as to synthesize the respective lasers, according to another embodiment of the light dividing means of the present invention.
13 is a view showing another embodiment of the image separating means according to the present invention. In this embodiment, a pinhole having different spatial positions in which four or more rays are formed is formed as a light dividing means by forming a lens having an enlargement ratio instead of the pyramidal prism, And schematically shows a state in which four images are divided and acquired in a charge coupled device (CCD).

Hereinafter, preferred embodiments of an interferometer having a multi-interference phase simultaneous measurement function according to the present invention will be described in more detail with reference to the accompanying drawings.

Hereinafter, the same reference numerals will be used to denote the same or similar elements in all of the following drawings, and repetitive descriptions will be omitted. The following terms are defined in consideration of the functions of the present invention. It should be interpreted as meaning.

5 to 11, the present invention includes a light source 501, a beam expander 502, a condenser lens (objective lens) 503, a beam splitter 505, A collimation lens 506, a reference spheres 507, a test spheres 508, a rotating diffuser disk 509, a mirror 510, a transmittance variable filter A light splitting means 504 is provided to an interferometer including a CCD (Graded ND Filter Disk) 511, an image forming lens 512, an image separating means 513 and a charge coupled device 514 .

In other words, on one side of the condenser lens 503, the emitted light is diverged so as to have four or more phase differences, not parallel light, and divergence or convergence is performed on the parallel light ray (phase 0 °) after passing through the collimator lens 506 Light splitting means 504 is formed so as to be incident on the reference spherical surface 507 or the test spherical surface 508.

Accordingly, it is possible to simultaneously measure a plurality of interference fringes by the phase difference of each ray diverging and converging while diverging at different angles by the light splitting means 504.

The light splitting means 504 may be formed of any one of a pinhole 504a, a hologram element 504b, a birefringent crystal 504c, a semi-transmission mirror 504d and an optical fiber 504e having a plurality of holes, It is preferable that the hologram element 504b, the birefringent crystal 504c, and the semi-transmissive mirror 504d are formed so as to form a pair.

In addition, the image separating means 513 is a pyramid-shaped prism, and the image separating means 513a is a CGH hologram (Computer Generated Hologram).

The image separating means 513 and 513a having such a constitution can be used as the image separating means 513a and 513a in the case where the light dividing means 504 is arranged in the form of a pinhole 504a, a half mirror 504d or an optical fiber 504e It is preferable to form the image separating means 513 made of a pyramidal prism when the focal point is located at a different position on the space.

However, when the light splitting means 504 focuses the light beams divided by the hologram element 504b and the birefringent crystal 504c along the optical axis, it is defocused. , It is preferable to form the image separating means 513a composed of a CGH hologram (Computer Generated Hologram).

The pinhole 504a formed with the plurality of holes is formed at a forward point formed by the condenser lens 503 so that four or more holes are formed so that the proceeding rays have different phase differences of four or more do.

In addition, the pinhole 504a is preferably formed so that each hole is inclined so that the distance from the collimating lens 506 is changed so that each ray passing therethrough has a phase difference.

Accordingly, since the light beams passing through the holes of the pinhole 504a have different phase distances due to mutual progress distances, the light beams traveling to the reference spherical surface 507 and the test spherical surface 508 are reflected by the pyramidal prisms And the plurality of interference fringes having different phase differences are simultaneously formed in the charge coupled device 514 by reflection or refraction.

That is, in the conventional interferometer, the light wavefront transmitted through the collimator lens is configured to collimate in parallel with the optical axis while being parallel to the optical axis. However, in the present invention, / 2 < / RTI > so as to have multiple phases.

The hologram element 504b is in the form of a two-dimensional diffraction grating and has the same form as that in which two one-dimensional diffraction gratings perpendicular to each other are superimposed. The hologram element 504b is inclined by 45 degrees around the grating direction of the reference grating when viewed from the optical axis (m, n) diffraction component, the interference fringes are recorded so as to divide the incident light into a plurality of light beams.

Accordingly, the hologram element 504b causes the light beams transmitted through the hologram element 504b to enter the collimator lens 506 with different divergent angles.

The hologram element 504b is disposed in front of the pinhole and spaced apart from the pinhole.

The hologram element 504b having such a constitution allows the proceeding rays to be divided into (+ 1st order and 0th order) diffraction components, (0th order, -1th order) diffraction components, (0th order, 1 < th > and 0 < th >) diffraction components.

That is, a plurality of light beams propagating to both sides through the hologram element 504b become reference light (reference beam) traveling to the screen, and the other light beams on the other side are optical components to be measured It becomes a progressive test beam.

Generally, the hologram element is made by interfering with reference light and reference light. Recently, computer generated hologram (CGH) produced by computer simulation has been widely used.

Accordingly, the plurality of light beams that pass through the hologram element 504b and diverge to both sides are formed to have different phase angles due to different angles of progression along the optical axis, so that they travel to the reference spherical surface 507 and the test spherical surface 508, (CCD) 514 by separating the images while passing through the image separating means 513a made up of a computer-generated hologram, and are simultaneously formed into a plurality of interference fringes having different phase differences.

When the birefringent crystal 504c passes through a crystal of a crystal (crystal), which is a single crystal of quartz (SiO2) and forms a crystal axis and a crystal plane, passes through a pinhole in which a single hole is formed, A first crystal 504c-1 installed to be positioned forward of the pinhole to cause a double refraction through the first crystal 504c-1 and a second crystal 504c- And a second crystal 504c-2 disposed so as to be positioned with respect to the second crystal 504c-2.

It is preferable that the birefringence crystal 504c uses a crystal having a refractive index different from that of light that oscillates in a direction perpendicular to a light ray emitted from the pinhole and that that oscillates in a horizontal direction.

It is preferable that the birefringent crystal 504c is installed at an angle rotated by 45 ° with respect to the first crystal 504c-1 in order to obtain four or more divergent rays.

Accordingly, the light rays passing through the birefringent crystal 504c are diverged into a plurality of light beams having mutually different angles going along the optical axis, proceeding to the reference spherical surface 507 and the test spherical surface 508, The image is separated while being passed through the image separating means 513a composed of the generated hologram and is simultaneously imaged on the charge coupled device (CCD) 514 with several interference fringes having different phase differences.

The semi-transmissive mirror 504d is formed of a first reflective surface, a second reflective surface, a third reflective surface, and a fourth reflective surface, wherein some rays of light are reflected by the first reflective surface, Of the light rays that are reflected from the reflection surface and transmitted from the second reflection surface, some are reflected from the third reflection surface, and some light rays are transmitted.

Then, the light beam transmitted through the third reflecting surface is finally reflected at the fourth reflecting surface.

The fourth reflection surface should be a total reflection mirror coating, but the first, second, and third reflection surfaces should be partially reflective coated with transmittance and reflectance, and to have the same amount of light of the four separated rays, , 2, and 3 reflective surfaces should be coated differently

In addition, the semi-transmission mirror 504d is installed so as to have a constant inclination angle with respect to the pin hole.

 Accordingly, the light beams traveling through the one hole are refracted so as to have different phase differences on the first, second, third, and fourth reflection surfaces of the half mirror 504d, (Medium), and the traveling direction changes.

Therefore, the light beam traveling through the pinhole by the semi-transmission mirror 504d is emitted to a plurality of light beams having different distances from the collimator lens 506 and the pinhole, and is transmitted through the reference spherical surface 507 and the test spherical surface 508 And is reflected or refracted by the image separating means 513 made of a pyramid-shaped prism, so that the image is simultaneously formed on the charge coupled device 514 by a plurality of interference fringes having different phase differences.

The optical fiber 504e is formed so that at least four optical fibers are bundled and one end is positioned at a focal point of the condenser lens 503 and the other end of the optical fiber 504e is formed such that each optical fiber has a length difference And is formed so as to be spread to different positions in space.

Accordingly, the light beams passing through the respective optical fibers converge or diverge slightly with respect to the parallel light rays when passing through the collimator lens 506 due to the difference in length of the optical fibers, so that the light beams having different phase differences form the light beams The light rays proceeding to the spherical surface 507 and the test spherical surface 508 and reflected are reflected or refracted by the image separating means 513 made of a pyramidal prism so that the charge coupled device 514 has a plurality of And are simultaneously imaged with interference fringes.

The hologram element 504b except the pinhole 504a and the optical fiber 504e, which form a plurality of holes, for example, four or more holes to form the light splitting means by itself, The pinhole formed in one hole, which is formed to be in pair with any one of the crystal 504c and the semi-transmissive mirror 504d, is formed to be perpendicular to the collimating lens 506. [

That is, the pinhole 504a having a plurality of holes is provided so as to be tilted so as to divide the light beam traveling through the collimator lens 506 into a plurality of light beams forming a phase difference, The pinhole in which one hole is formed so as to form a pair with any one of the birefringent crystal 504b, the birefringent crystal 504c and the semi-transmissive mirror 504d is formed by combining a light beam focused via the condenser lens 503, It emits with rays.

As described above, the present invention allows the light rays emitted from the reference lens 507 to have a plurality of focal lengths without moving the reference lens 507 to obtain interference fringes of various phases.

That is, by forming the light splitting means 504 such that the light beam incident on the reference lens 507 after being transmitted through the collimator lens 506 is divided into a plurality of light beams having different angles, The light rays emitted from the pinhole may be different from each other or the distance between the pinhole and the collimator lens 506 may be different and the proceeding light may be incident on the reference lens 507 at different angles after passing through the collimator lens 506 As a result, the focal point adjustment position by the reference lens 507 is made different.

When the light splitting means 504 according to the present invention is composed of the pin hole 504a, the semi-transmission mirror 504d or the optical fiber 504e, It is preferable to use a pyramidal prism as the image separating means 513 in order to easily acquire four or more images in a charge-coupled device (CCD) 514.

The image separating means 513 having such a configuration is divided into four or more images by the reflection or refraction and divided into the charge-coupled device (CCD) 514 by the light beam proceeding by the pyramidal prism.

For example, when the light beams traveling on the image separating means 513 composed of the pyramidal prisms are reflected, each image is reflected through the four sides of the pyramidal prism, so that four charge coupled And a device (CCD) 514 is provided to divide and acquire each image.

When each of the images is refracted while passing through the pyramid-shaped prism, a single charge coupled device (hereinafter, referred to as " prism ") 513 disposed in front of the image separating means 513, (CCD) 514 in order to acquire four or more images.

That is, when the position of each image formed in the space is different, such as the pinhole 504a, the semi-transmission mirror 504d, or the optical fiber 504e, by using the image separating means 513 composed of a pyramidal prism, (CCD) 514, as shown in FIG.

However, when using the light splitting means 504 such as the hologram element 504b and the birefringent crystal 504c which is defocused (proceeding to be out of focus) while proceeding along the optical axis, a CGH hologram (CCD) 514 by using an image separating means 513a which is composed of a CCD (Charge Coupled Device) and a CCD (Charge Coupled Hologram).

Hereinafter, the operation of the present invention will be described in more detail.

First, a light beam generated by the light source 501 is emitted and advanced to a light expander 502.

The light beam traveling to the optical expander 502 is expanded into parallel light and then focused by the condenser lens 503. At the same time, four or more divergent angles are divided by the light divider 504 into different light beams, 505).

The light beams having passed through the optical splitter 505 pass through a collimation lens 506 and are reflected from a reference sphere 507 and a test sphere 508, respectively.

The reflected waves of the two spherical surfaces interfere with each other to produce an interference fringe. The interference fringes are incident on the collimator lens 506, reflected by the optical splitter 505 by 90 degrees, and imaged onto a rotating diffuser disk 509.

The rotation diffusion filter 509 removes the spark to obtain a clean interference fringe image.

The interference fringes imaged on the rotation diffusion filter 509 pass through a Graded ND Filter Disk 511 and an image forming lens 512 that reflect the incident light by 90 ° in the mirror 510 (CCD) 514 through an image separating means 513 made up of a pyramid-shaped prism or an image separating means 513a made up of a CGH hologram (Computer Generated Hologram).

Therefore, when the light beam traveling by the light splitting means 504 is diverged into a plurality of light beams having different angles, or when the divergence angles are the same, a distance from the collimator lens 506 is different, (CCD) 514 by reflecting and converging with respect to the rear parallel light and proceeding to the reference spherical surface 507 and the test spherical surface 508 and reflecting the incident light to a plurality of interference fringes The reference spherical surface 507 is not moved, so that the influence of the interference fringe caused by the flow of convection or the like is not affected, so that precise and accurate shape information of the measurement surface can be obtained.

12 is a view showing another embodiment according to the present invention, in which the light dividing means 504 is formed by a plurality of lasers having different wavelengths from the light source 501, so that light rays of different wavelengths So that the divergent angle is made different from that of the collimated lens 506 according to the different refractive indexes of the wavelengths, thereby obtaining a plurality of interference fringes having different phase differences.

As described above, in the configuration of the interferometer in which a plurality of lasers having different wavelengths are used as a light source, four or more optical fibers are formed in a bundle, and the pinholes forming one hole have the same wavefront, The angle at which the collimated lens material is collimated by the difference in refractive index is different.

13 is a view showing another embodiment of the image separating means according to the present invention, in which the image separating means 513b is formed of a lens having an enlargement ratio instead of the pyramidal prism, A plurality of interference fringes having different phase differences are formed in a separated position of one charge coupled device (CCD) 514 by enlarging a focus interval of each image divided into a plurality of images, And the interference fringes having different phase differences are formed on the four charge coupled devices (CCD)

The image separating means 513b having such a constitution is arranged so that the focus of each light beam split by the light dividing means 504 such as the pinhole 504a, the semi-transmission mirror 504d or the optical fiber 504e is a spatial image It is preferable that the present invention is mainly applied to a case where the position of the light emitting diode is different.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. And will be apparent to those skilled in the art to which the invention pertains.

501: light source 502: light expander
503: condenser lens (objective lens) 504:
504a: pin hole (four holes) 504b: hologram element
504c: birefringent crystal 504c-1: first crystal
504c-2: second crystal 504d: semi-transmission mirror
504e: optical fiber 505: optical separator
506: collimator lens 507: reference spherical surface
508: test spherical surface 509: rotation diffusion filter
510: mirror 511: transmittance variable filter
512: imaging lens 513, 513a, 513b:
514: charge-coupled device (CCD)

Claims (10)

A light source, a light expander, a condenser lens (objective lens), a light separator, a collimator lens, a reference spherical surface, a test spherical surface, a rotation diffusion filter, a mirror, an imaging lens, a variable transmittance filter, As an interferometer,
A light splitting means for dividing a light beam emitted from the condenser lens or the pinhole into a plurality of light beams is formed on one side of the condenser lens so that light beams emitted from the reference lens are not collimated light but proceed at four or more divergence and convergence angles, Spherical or test spherical surface so that four or more interference fringes due to the phase difference of each ray diverging and converging at different angles are measured at the same time. The method according to claim 1,
Wherein the image separating means comprises any one of a CGH hologram, a pyramidal prism or a lens having an enlargement magnification, and the light splitting means is any one of a pinhole having a plurality of holes, a hologram element, a birefringent crystal, a semitransparent mirror, And the interferometer has a function of simultaneously measuring a multi-interfering phase. 3. The method of claim 2,
When the light splitting means is formed of a pinhole, a semi-transmission mirror or an optical fiber, since four or more light beams traveling in different directions have different spatial positions to be respectively formed, four or more images are easily acquired in a charge coupled device Characterized in that the image separating means uses a pyramidal prism or a lens having an enlargement magnification. 3. The method of claim 2,
Wherein the pinhole is formed at a front point formed by the condenser lens so that at least four holes are formed so that the proceeding light ray has four or more different phase differences and each hole has a phase difference, Wherein the interference fringes are formed so that the distance from the collimating lens is varied. 3. The method of claim 2,
The birefringent crystal is provided with a first crystal and a second crystal. The second crystal is provided at an angle rotated by 45 degrees with respect to the first crystal to produce a ray having multiple divergent angles by the birefringence component of the crystal, Wherein the interferometer has a function of simultaneously measuring a multi-interference phase. 3. The method of claim 2,
Wherein the transflective mirror is formed of a first reflective surface, a second reflective surface, a third reflective surface, and a fourth reflective surface. 3. The method of claim 2,
The optical fiber is formed so that four or more optical fibers are bundled, one end of the optical fiber is positioned at a focal point of the condenser lens, and the other end of the optical fiber is formed such that the optical fibers are mutually different in length, Wherein the interferometer is configured to expand at different spatial locations. 3. The method of claim 2,
Wherein the hologram element is configured to cause the light beams transmitted through the hologram element to be incident on the collimator lens at different divergent angles. The method of claim 3,
Wherein the image separating means made up of the pyramidal prism separates four or more images into the charge coupled device (CCD) by reflection or refraction. 10. The method of claim 9,
The image separating means made up of the pyramidal prism uses four charge coupled devices (CCDs) for separating and imaging four or more images by reflection, and when four or more images are separated and formed by refraction, An interferometer having a simultaneous multi-interference phase measurement function using one charge coupled device (CCD).

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