JP2011220979A - Aberration measurement apparatus and aberration measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aberration measurement apparatus and an aberration measurement method with which more accurate detection can be performed.SOLUTION: An aberration measurement apparatus for measuring aberration of an optical system has: a light gathering optical system for forming multiple light spots on a predetermined surface by dividing wave fronts via the optical system and gathering the light; a detecting part which includes an imaging device for detecting the multiple light spots and calculates aberration of the optical system based on the result of detection from the imaging device; and a driving part for performing relative movement of the multiple light spots and an imaging part of the imaging device. The detecting part calculates aberration of the optical system based on the respective detection results from the imaging device before and after the relative movement performed by the driving part.

Description

  The present invention relates to an aberration measuring apparatus and an aberration measuring method.

  When measuring wavefront aberration of the imaging optical system, the wavefront is divided, the divided parts are imaged as spots by the condensing element, and the wavefront aberration is measured from the amount of change in the detected spot position. An aberration measuring device is used. A typical example is a Shack Hartmann type aberration measuring apparatus. The Shack-Hartmann aberration measurement apparatus detects a plurality of light spots formed by, for example, a lens array, and detects aberrations of the optical system based on the detection result. For the detection of the light spot, for example, an imaging apparatus provided with a two-dimensional light receiving element such as a CCD camera is used.

JP 2004-61238 A

  However, since the measurement accuracy of the aberration measuring apparatus having the above configuration depends on the light reception accuracy of the two-dimensional light receiving element, a two-dimensional light receiving element with a finer pixel pitch is required, for example, when measuring aberration with high accuracy. . Since there is a limit to the fineness of the pixel pitch, it becomes a problem when realizing more accurate measurement.

  In view of the circumstances as described above, an object of the present invention is to provide an aberration measuring apparatus and an aberration measuring method capable of detecting with higher accuracy.

  According to the first aspect of the present invention, there is provided an aberration measuring apparatus for measuring an aberration of an optical system, in which a wavefront of light passing through the optical system is divided and condensed to form a plurality of light spots on a predetermined surface. A condensing optical system to be formed, an imaging device that detects a plurality of light spots, a detection unit that calculates aberrations of the optical system based on a detection result of the imaging device, and imaging of the plurality of light spots and the imaging device And an aberration measuring device that calculates the aberration of the optical system based on each detection result of the imaging device before and after the relative movement by the driving unit.

  According to a second aspect of the present invention, there is provided an aberration measuring method for measuring aberrations of an optical system, in which a wavefront of light passing through the optical system is divided and condensed to form a plurality of light spots on a predetermined surface. A spot forming step to be formed; a detection step of detecting a plurality of light spots by an imaging device; and calculating aberrations of the optical system based on a detection result of the imaging device; An aberration measuring method for calculating the aberration of the optical system based on each detection result of the imaging device before and after the relative movement by the moving step.

  According to the present invention, detection with higher accuracy is possible.

The figure which shows the structure of the aberration measuring apparatus which concerns on 1st Embodiment of this invention. The figure which shows the measurement principle of an aberration measuring device. The flowchart which shows operation | movement of the aberration measuring apparatus which concerns on this embodiment. The figure which shows operation | movement of the aberration measuring apparatus which concerns on this embodiment. The figure which shows the structure of the aberration measuring apparatus which concerns on 2nd Embodiment of this invention. The figure which shows the structure of the aberration measuring apparatus which concerns on 3rd Embodiment of this invention. The figure which shows the structure of the aberration measuring apparatus which concerns on 4th Embodiment of this invention.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of an aberration measuring apparatus according to the present embodiment.
As shown in FIG. 1, the aberration measuring device 11 measures the aberration of the optical system 12 to be measured. The aberration measuring device 11 includes a light source device IL, a base material Rt, a condensing optical system 13, an imaging device 17, a driving device ACT, and a control device CONT. The optical system 12 that is the measurement target is disposed between the base material Rt and the condensing optical system 13, for example.

  Hereinafter, the configuration of the aberration measuring apparatus 11 will be described using an XYZ orthogonal coordinate system. In the present embodiment, the traveling direction of the light emitted from the light source device IL is the Z-axis direction. In addition, two orthogonal directions on the plane perpendicular to the Z direction are defined as an X-axis direction and a Y-axis direction, respectively. In addition, directions around the X axis, the Y axis, and the Z axis may be expressed as θX, θY, and θZ, respectively.

  For example, the light source device IL emits parallel light to the base material Rt. The base material Rt has a pinhole PH. For example, light incident on the pinhole PH from the −Z side is emitted as a spherical wave SW from the + Z side of the pinhole PH.

  The condensing optical system 13 includes, for example, a collimator lens 14 and a micron lens array 15. The collimator lens 14 converts the spherical wave SW emitted from the optical system 12 into parallel light PB. The micron lens array 15 has a plurality of lenslets 16. The micron lens array 15 divides the wavefront of the parallel light PB for each lenslet 16. The lenslets 16 are arranged in a matrix, for example, on the XY plane. Each lenslet 16 condenses the divided parallel light PB on the surface (spot forming surface 17b) on the −Z side of the imaging device 17, and forms a light spot SP on the spot forming surface 17b.

  The imaging device 17 detects the light spot SP formed by the lenslet 16. As the imaging device 17, for example, a two-dimensional light receiving element 17a such as a CCD camera is used. The two-dimensional light receiving element 17a has a plurality of pixels PX. The plurality of pixels PX are arranged in a matrix on the XY plane, for example. The plurality of pixels PX are arranged at a predetermined pitch t1 in the X direction and the Y direction, for example.

  In FIG. 1, an example in which the number of pixels PX corresponding to the lenslets 16 is arranged is shown, but a plurality of pixels PX are actually arranged for one lenslet 16. For this reason, the light spot SP formed by one lenslet 16 is received by a plurality of pixels PX, and the center of gravity of the spot is obtained. The imaging result by the imaging device 17 is transmitted to, for example, the control device CONT.

  The drive device ACT includes an actuator (not shown) that drives the base material Rt in the X direction, the Y direction, and the Z direction, for example. In the drive device ACT, for example, the drive amount of the base material Rt is adjusted by the control device CONT.

The measurement principle of the aberration measuring apparatus 11 configured as described above will be described.
As shown in FIG. 2A, when there is no aberration in the optical system 12, the parallel light PB incident on the lenslet 16 has a parallel wavefront WFpn. For this reason, the light spot SP by each micron lens array 15 of the lenslet 16 is imaged on the optical axis Axn of each micron lens array 15.

  On the other hand, as shown in FIG. 2B, when there is an aberration in the optical system 12, the parallel light PB incident on the micron lens array 15 has a wavefront WFpa distorted according to the wavefront aberration. For this reason, the parallel light PB has a different slope Axp of the wavefront WFpa for each micron lens array 15. Then, the light spot SP by each micron lens array 15 forms an image at a position shifted laterally from the optical axis Axn according to the inclination amount of the wavefront WFpa for each lenslet 16. As described above, the aberration of the optical system 12 can be measured as the wavefront aberration by obtaining the inclination Axp of the wavefront WFpa from the lateral shift amount of the imaging position of the light beam for each micron lens array 15.

Next, the operation of the aberration measuring apparatus 11 will be described. FIG. 3A is a flowchart showing the operation of the aberration measuring apparatus 11. Hereinafter, a description will be given with reference to FIG. 3A.
First, light is irradiated from the light source device IL to the pinhole PH of the base material Rt. This light passes through the pinhole PH and becomes a spherical wave SW. The spherical wave SW is irradiated onto the optical system 12 from the −Z plane side (irradiation step: ST01). The spherical wave SW irradiated to the optical system 12 is emitted from the + Z plane side of the optical system 12. The emitted spherical wave SW is imaged by the optical system 12 and then converted into parallel light PB by the collimator lens 14.

  The parallel light PB is incident on a lenslet 16 in which a large number of micron lens arrays 15 are two-dimensionally arranged. The wavefront of the parallel light PB is divided by the lenslet 16 and forms an image on the spot forming surface 17b of the imaging device 17. For this reason, the light spot SP of the split light is formed on the spot forming surface 17b (spot forming step: ST02). In the present embodiment, one light spot SP is disposed so as to straddle the plurality of pixels PX.

  Next, the plurality of light spots SP formed on the spot forming surface 17b of the imaging device 17 and the plurality of pixels PX of the imaging device 17 are relatively moved (moving step: ST03). This moving process is performed to form a state before and after the positional relationship on the XY plane changes between the plurality of pixels PX and the centers of gravity of the plurality of light spots SP. Here, a state in which the positional relationship between the center of gravity of the light spot SP and the pixel PX is established before the moving step is defined as a first state, and a state in which the positional relationship between the two is established after the moving step is defined as a second state. State. In order to form these two states, in this embodiment, as a moving process, the control device CONT fixes the position of the imaging device 17, for example, and moves the base material Rt in at least one of the X direction and the Y direction. I will do it.

FIG. 3B is a diagram illustrating a state before and after the moving process.
In the first state before the moving process, for example, a light spot SP1 is formed at a predetermined position on the spot forming surface 17b of the imaging device 17 (indicated by a one-dot chain line in the figure). In FIG. 3B, each light spot SP1 is formed in the center of each pixel PX, for example.

  From this first state, the control device CONT moves the base material Rt in the −X direction. By this movement, the pinhole PH as a point light source moves in the −X direction, and the light spot SP moves accordingly. Since the plurality of light spots SP move and the positions of the plurality of pixels PX are fixed, the positions at which the plurality of light spots are formed on the plurality of pixels PX move along the spot forming surface 17b. For example, in FIG. 3B, a predetermined distance t2 is displaced along the XY plane with respect to the position where the light spot SP1 in the first state is formed. As a result, the light spot SP2 is formed at the −X side end of each pixel PX.

  Before and after the moving process, the positional relationship on the XY plane between the positions of the plurality of pixels PX and the light spot SP is different. That is, in the example of the present embodiment, the first state is a state in which the center of gravity of each light spot SP1 is formed so as to coincide with the center of one pixel PX among the plurality of pixels PX. The second state is a state in which the center of gravity of each light spot SP2 is formed so as to coincide with the end of one pixel PX among the plurality of pixels PX. Thus, the second state is achieved by performing relative movement between the plurality of pixels PX and the plurality of light spots SP from the first state.

  In the present embodiment, the control device CONT detects the light spot SP by the imaging device 17 before and after the relative movement by the movement process. That is, the light spot SP is detected using the imaging device 17 in each of the first state and the second state. The control device CONT detects the arrangement state of the light spots SP based on the detection results of the first state and the second state, and calculates the aberration of the optical system based on the detection result (detection step: ST04).

  In the moving step, the control device CONT adjusts the driving amount of the base material Rt so that the moving amounts t2 of the plurality of light spots SP are smaller than the pitch t1 of the plurality of pixels PX. That is, the control device CONT positions the center of gravity of the light spot SP after the relative movement with an accuracy finer than the pitch t1 of the plurality of pixels PX. By this operation, the intensity profile of the center of gravity of each light spot SP is detected at a pitch finer than the pixel pitch. Further, the relative movement is performed a plurality of times in the moving step, and the aberration of the optical system 12 may be calculated using the detection results of the imaging device 17 before and after the plurality of relative movements in the detecting step. Absent. Thereby, the detection accuracy is further improved.

  As described above, according to the present embodiment, the aberration measuring device 11 measures the aberration of the optical system 12 and divides the wavefront of the light that has passed through the optical system 12 to condense and collect the light on the spot forming surface 17b. The light collecting optical system 13 that forms a plurality of light spots SP and the imaging device 17 that detects the plurality of light spots SP are calculated, and the aberration of the optical system 12 is calculated based on the detection result of the imaging device 17. A control device CONT, and a driving device ACT that performs relative movement between the plurality of light spots SP and the two-dimensional light receiving element 17a of the imaging device 17, and the control device CONT is an imaging device before and after relative movement by the driving device ACT. Since the aberration of the optical system 12 is calculated based on the respective detection results of 17, the detection with higher accuracy can be performed beyond the accuracy of the two-dimensional light receiving element 17a.

[Second Embodiment]
Next, an aberration measuring apparatus according to the second embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified. In the present embodiment, since the configuration for performing relative movement between the light spot and the pixel is different from that in the first embodiment, the configuration related to the difference will be mainly described.

FIG. 4 is a diagram illustrating a configuration of the aberration measuring apparatus 211 according to the present embodiment.
As shown in FIG. 4, in the aberration measuring apparatus 211, a parallel plate PR is disposed between the base material Rt and the optical system 12. The parallel plate PR is formed of a material having a predetermined refractive index with respect to the spherical wave SW emitted from the pinhole PH. The spherical wave SW is emitted from the pinhole PH and enters the optical system 12 via the parallel plate PR.

The driving device ACT drives the parallel plate PR instead of the base material Rt. The driving device ACT drives the parallel plate PR so that the parallel plate PR rotates in the θX direction or the θY direction, for example. The incident angle and the incident range of the spherical wave SW with respect to the optical system 12 are changed by the rotation of the parallel plate PR.
Except for the configuration described above, the configuration is almost the same as that of the first embodiment.

Next, the operation of the aberration measuring apparatus 211 according to this embodiment will be described.
First, the control device CONT irradiates light from the light source device IL to the base material Rt. The light passing through the pinhole PH becomes a spherical wave SW and enters the parallel plate PR. The parallel flat plate PR at this time is arranged in parallel to the XY plane, for example, as shown by a one-dot chain line in FIG. The spherical wave SW incident on the parallel plate PR is irradiated to the optical system 12 (irradiation process). The spherical wave SW irradiated to the optical system 12 is emitted as split light from the lenslet 16 via the collimator lens 14 and the micron lens array 15, and a plurality of light spots SP1 are formed on the spot forming surface 17b of the imaging device 17. (Spot forming step).

  Next, the control device CONT performs relative movement between the plurality of light spots SP1 and the plurality of pixels PX (movement process). The concept of relative movement is the same as in the first embodiment. That is, two states (first state and second state) in which the positional relationship between the centers of gravity of the plurality of light spots SP and the plurality of pixels PX are different are formed. The state before the moving process is the first state, and the state after the moving process is the second state.

  In the moving process, the control device CONT operates the drive device ACT to rotate the parallel plate PR in at least one of the θX direction and the θY direction. By the rotation of the parallel plate PR, the incident angle and the incident range of the spherical wave SW with respect to the optical system 12 change. Therefore, the spherical wave SW emitted from the optical system 12 follows an optical path different from the optical path in the first state, and a light spot SP2 is formed via the collimator lens 14 and the lenslet 16. In this way, the second state is formed. The light spot SP2 in the second state is formed at a position shifted from the light spot SP1 in the first state.

  As in the first embodiment, the control device CONT detects the light spot SP by the imaging device 17 before and after the relative movement by the movement process. That is, the center of gravity of the light spot SP is detected using the imaging device 17 in each of the first state and the second state. The control device CONT detects the arrangement state of the light spots SP based on the detection results of the first state and the second state, and calculates the aberration of the optical system based on the detection result (detection step). Also in this embodiment, in order to increase the detection accuracy, the rotation angle of the parallel plate PR is adjusted so that the movement amount of the center of gravity of the plurality of light spots SP in the movement process is smaller than the pitch t1 of the plurality of pixels PX. It is preferable to do.

  As described above, according to the present embodiment, the parallel plate PR that transmits light and irradiates the optical system 12 is provided, and the drive device performs relative movement by changing the light irradiation angle by the parallel plate PR. Since it did in this way, relative movement can be performed, without changing the position of light source device IL and base material Rt.

[Third Embodiment]
Next, an aberration measuring apparatus according to the third embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified. In the present embodiment, since the configuration for performing relative movement between the light spot and the pixel is different from that in the first embodiment, the configuration related to the difference will be mainly described.

FIG. 5 is a diagram illustrating a configuration of the aberration measuring apparatus 311 according to the present embodiment.
As shown in FIG. 5, the aberration measuring device 311 is configured such that the spherical wave SW from the light source device IL is reflected by the light reflecting member MR and irradiated onto the optical system 12. The driving device ACT drives the light reflecting member MR. The driving device ACT drives the light reflecting member MR so that the light reflecting member MR rotates in, for example, the θX direction or the θY direction. The incident angle and the incident range of the spherical wave SW with respect to the optical system 12 are changed by the rotation of the light reflecting member MR. Except for the configuration described above, the configuration is almost the same as that of the first embodiment.

Next, the operation of the aberration measuring apparatus 311 according to this embodiment will be described.
The control device CONT irradiates light from the light source device IL to the light reflecting member MR. The spherical wave SW is reflected by the light reflecting member MR and irradiated onto the optical system 12 (irradiation process). The spherical wave SW irradiated to the optical system 12 is emitted as split light from the lenslet 16 via the collimator lens 14 and the micron lens array 15, and a plurality of light spots SP1 are formed on the spot forming surface 17b of the imaging device 17. (Spot forming step).

  Next, the control device CONT performs relative movement between the plurality of light spots SP1 and the plurality of pixels PX (movement process). The concept of relative movement is the same as in the first embodiment. In the moving process, the control device CONT operates the drive device ACT to rotate the light reflecting member MR in at least one of the θX direction and the θY direction.

  By the rotation of the light reflecting member MR, the incident angle and the incident range of the spherical wave SW with respect to the optical system 12 change. Therefore, the spherical wave SW emitted from the optical system 12 follows an optical path different from the optical path in the first state, and a light spot SP2 is formed via the collimator lens 14 and the lenslet 16. In this way, the second state is formed. The light spot SP2 in the second state is formed at a position shifted from the light spot SP1 in the first state.

  The control device CONT detects the center of gravity of the light spot SP by the imaging device 17 before and after the relative movement in the movement process, as in the first embodiment, and the detection result of the first state and the second state as in the above embodiment. Based on the above, the center of gravity of the light spot SP is detected, and the aberration of the optical system is calculated based on the detection result (detection step). Also in this embodiment, in order to increase the detection accuracy, the rotation angle of the parallel plate PR is adjusted so that the movement amounts of the plurality of light spots SP in the movement process are smaller than the pitch t1 of the plurality of pixels PX. Is preferred.

  As described above, according to the present embodiment, the light reflection member MR that reflects the light from the light source is provided, and the driving device changes the irradiation angle of the light that is applied to the optical system 12 via the light reflection member MR. As a result, the relative movement is performed, so that the detection can be performed with higher accuracy than the accuracy of the two-dimensional light receiving element 17a as in the above embodiment.

[Fourth Embodiment]
Next, an aberration measuring apparatus according to the fourth embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified. In the present embodiment, the drive target of the drive device is different from that of the first embodiment, and therefore, the configuration related to the difference will be mainly described.

FIG. 6 is a diagram illustrating a configuration of the aberration measuring apparatus 411 according to the present embodiment.
As shown in FIG. 6, the aberration measuring device 411 is different from the first embodiment in that the drive target of the drive device ACT is not the base material Rt but the imaging device 17. About the structure of other than that, it has the structure substantially the same as 1st Embodiment.

About the operation | movement of the aberration measuring device 411 which concerns on this embodiment, about an irradiation process and a spot formation process, it is the same as that of 1st Embodiment.
When performing relative movement in the movement process, the control device CONT moves the imaging device 17 in at least one of the X direction and the Y direction. By this movement, two states (first state and second state) having different positional relationships between the plurality of light spots SP and the plurality of pixels PX can be formed.

  In this case, the position of the plurality of pixels PX moves while the position where the light spot SP is formed is fixed. Moreover, about a detection process, it can carry out by the process similar to 1st Embodiment. As described above, even when the plurality of pixels PX are moved instead of the plurality of light spots SP, relative movement is possible.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
For example, in the first embodiment, the configuration in which the base material Rt is moved in at least one of the X direction and the Y direction has been described as an example. However, the present invention is not limited to this. For example, the base material Rt is set in the Z direction. It may be moved to.

  In this case, the power component is superimposed on the wavefront of the parallel light PB incident on the lenslet 16. For example, when a convex power component is superimposed, the light spot SP2 formed by each lenslet 16 is aligned with the optical axes of all optical systems including the aberration measuring device 11 and the optical system 12 with respect to the light spot SP1 in the first state. On the other hand, it is formed so as to spread radially.

  Further, for example, when a concave power component is superimposed, the light spot SP2 formed by each lenslet 16 is light of all optical systems including the aberration measuring device 11 and the optical system 12 with respect to the light spot SP1 in the first state. It is formed to gather on the shaft. Thus, by moving the base material Rt in the Z direction, relative movement can be performed between the plurality of light spots SP and the plurality of pixels PX.

IL ... Light source device Rt ... Base material ACT ... Drive device SW ... Spherical wave PB ... Parallel light SP, SP1, SP2 ... Light spot PX ... Pixel PR ... Parallel plate MR ... Light reflection member 11, 211, 311, 411 ... Aberration measurement Device 12 ... Optical system 13 ... Condensing optical system 17 ... Imaging device 17a ... Two-dimensional light receiving element 17b ... Spot forming surface CONT ... Control device

Claims (16)

An aberration measuring device for measuring aberration of an optical system,
A condensing optical system that divides the wavefront of the light through the optical system and condenses each to form a plurality of light spots on a predetermined surface;
A detector that detects a plurality of the light spots, and calculates an aberration of the optical system based on a detection result of the imaging device;
A driving unit that performs relative movement between the plurality of light spots and the imaging unit of the imaging device;
With
The detection unit calculates an aberration of the optical system based on each detection result of the imaging device before and after the relative movement by the driving unit. The drive unit performs the relative movement such that a plurality of the light spots and the imaging unit are relatively moved by a distance smaller than an arrangement pitch of the pixels with respect to an arrangement direction of the plurality of pixels of the imaging unit. 2. The aberration measuring apparatus according to 1. The drive unit performs the relative movement a plurality of times,
The aberration measurement device according to claim 1, wherein the detection unit calculates an aberration of the optical system using each detection result of the imaging device after a plurality of relative movements. The detection unit calculates an arrangement state of the plurality of light spots based on detection results of the imaging apparatus before and after the relative movement, and calculates aberrations of the optical system based on the arrangement state. The aberration measuring device according to any one of claims 1 to 3. A light source that irradiates the light to the optical system;
The aberration measuring device according to claim 1, wherein the driving unit performs the relative movement in a direction orthogonal to the traveling direction of the light. A light source that irradiates the light to the optical system;
The aberration measuring apparatus according to claim 1, wherein the driving unit performs the relative movement in a traveling direction of the light. The light source has a light reflecting member that reflects the light toward the optical system,
The aberration measuring apparatus according to claim 5, wherein the drive mechanism performs the relative movement by changing a reflection angle of the light by the light reflecting member. The light source has a prism that transmits the light and irradiates the optical system;
The aberration measuring apparatus according to claim 5, wherein the driving mechanism performs the relative movement by changing an irradiation angle of the light by the prism. An aberration measurement method for measuring aberration of an optical system,
A spot forming step of dividing a wavefront of light through the optical system and condensing each to form a plurality of light spots on a predetermined surface;
A detection step of detecting a plurality of the light spots by an imaging device, and calculating an aberration of the optical system based on a detection result of the imaging device;
A moving step of performing a relative movement between the plurality of light spots and the imaging unit of the imaging device,
The aberration measurement method, wherein the detection step calculates an aberration of the optical system based on each detection result of the imaging device before and after the relative movement by the movement step. The moving step performs the relative movement such that a plurality of the light spots and the imaging unit are relatively moved by a distance smaller than an arrangement pitch of the pixels with respect to an arrangement direction of the plurality of pixels of the imaging unit. 10. The aberration measuring method according to 9. The moving step performs the relative movement a plurality of times,
The aberration measurement method according to claim 9, wherein the detection step calculates an aberration of the optical system using each detection result of the imaging apparatus after the relative movement is performed a plurality of times. 10. The detection step calculates an array state of the plurality of light spots based on detection results of the imaging device before and after the relative movement, and calculates aberrations of the optical system based on the array state. The aberration measuring method according to claim 11. The spot forming step includes an irradiation step of irradiating the optical system with the light from a light source,
The aberration measuring method according to any one of claims 9 to 12, wherein the moving step includes performing the relative movement in a direction orthogonal to a traveling direction of the light. The spot forming step includes an irradiation step of irradiating the optical system with the light from a light source,
The aberration measurement method according to any one of claims 9 to 13, wherein the moving step includes performing the relative movement in a traveling direction of the light. The irradiation step includes irradiating the optical system with the light by reflecting the light toward the optical system,
The aberration measuring method according to claim 13 or 14, wherein the moving step includes changing a reflection angle of the light. The irradiation step includes irradiating the optical system with the light through a prism that transmits the light,
The aberration measurement method according to any one of claims 13 to 15, wherein the moving step includes changing an irradiation angle of the light by the prism.

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