Optical device and adjustment method

Abstract

To provide an optical device and an adjustment method with which it is possible to adjust zero-order light from diffraction light using a diffraction grating.SOLUTION: An optical device 1 according to the present embodiment comprises: a diffraction grating 10 that diffracts illumination light L1 including linearly polarized light; adjustment means 20 that passes at least some of the illumination light L1 through that includes diffracted light LD by the diffraction grating 10; and a support part 30 that supports the adjustment means 20. The adjustment means 20 includes a polarized light region 23 including, on a plane intersecting the optical axis C1 of the illumination light L1 and a straight line parallel to the optical axis C1, a polarization element that limits the passage of light other than the linearly polarized light in a prescribed direction, and the support part 30 supports the adjustment means so that the optical axis C1 passes through the polarized light region 23, and that the polarized light region 23 is rotatable on the plane.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to optical devices and adjustment methods. [Background technology]

[0002] Patent Document 1 discloses that in order to mitigate the effect of the zeroth-order light of the diffracted light having a high intensity distribution, a shielding portion that blocks the zeroth-order light of the diffracted light is provided on the Fourier plane of the diffracted light by the diffraction grating of the illumination light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-284237 Summary of the Invention [Problem to be solved by the invention]

[0004] The shielding portion of Patent Document 1 reduces the intensity of the zeroth-order light to almost zero, but it is preferable to be able to adjust the zeroth-order light of the diffracted light, for example, by more flexibly adjusting the intensity of the zeroth-order light of the diffracted light by the diffraction grating.

[0005] The present disclosure has been made in consideration of such problems, and provides an optical device and an adjustment method that can adjust the zeroth-order light in diffracted light using a diffraction grating. [Means for solving the problem]

[0006] The optical device according to one aspect of this embodiment includes: a diffraction grating that diffracts illumination light including linearly polarized light; The optical system comprises an adjustment means for transmitting at least a portion of the illumination light, including diffracted light diffracted by the diffraction grating, and a support portion for supporting the adjustment means, wherein the adjustment means has a polarization region on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis, the polarization region including a polarizing element that limits the transmission of light other than linearly polarized light in a predetermined direction, and the support portion supports the adjustment means so that the optical axis passes through the polarization region and so that the polarization region can be rotated on the plane.

[0007] In the above optical device, the adjustment means may further have a transmissive region on the plane surrounding the polarizing region, and the transmissive region may transmit light other than linearly polarized light in the specified direction through the polarizing region.

[0008] The optical device may further include a lens disposed between the diffraction grating and the adjusting means, and the adjusting means may be disposed on the Fourier plane of the lens.

[0009] In the optical device, the support portion may support the adjustment means such that the position of the adjustment means is displaceable in the direction of the optical axis.

[0010] In the optical device, when the illumination light illuminates an object via the diffraction grating and the adjusting means, The support portion may support the adjustment means at a position where a ratio between the intensity of the zeroth order light of the diffracted light contained in the illumination light that illuminates the object and the intensity of light other than the zeroth order light becomes a predetermined value.

[0011] The optical device may further include a waveguide, and at least a portion of the illumination light that has passed through the adjusting means may be incident on the waveguide.

[0012] In the above optical device, the polarization region through which the optical axis passes may be a first polarization region, and the adjustment means may have a second polarization region around the first polarization region on the plane that limits the transmission of light other than linearly polarized light in a direction different from the specified direction.

[0013] In the above optical device, the adjustment means may further have a transmissive region surrounding the second polarization region within the plane, and the transmissive region may transmit light other than linearly polarized light in the specified direction through the first polarization region, and transmit light other than linearly polarized light in a direction different from the specified direction through the second polarization region.

[0014] An adjustment method according to one aspect of this embodiment is a method for adjusting illumination light in an optical device comprising: a diffraction grating that diffracts illumination light including linearly polarized light; an adjustment means that transmits at least a portion of the illumination light including diffracted light diffracted by the diffraction grating, the adjustment means having a polarization region on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis, the polarization region including a polarizing element that limits the transmission of light other than linearly polarized light in a predetermined direction; a support unit that supports the adjustment means; and a control unit that controls the drive of the support unit, the method comprising the steps of: making the optical axis pass through the polarization region; and supporting the adjustment means so that the polarization region can be rotated on the plane.

[0015] In the above adjustment method, the adjustment means may further have a transmissive region on the plane that surrounds the polarizing region, and the transmissive region may transmit light other than linearly polarized light in the specified direction through the polarizing region.

[0016] In the above adjustment method, the optical device may include a lens disposed between the diffraction grating and the adjustment means, and the adjustment means may be disposed on a Fourier plane of the lens.

[0017] The above adjusting method may further include a step of supporting the adjusting means on the support section so that the position of the adjusting means can be displaced in the direction of the optical axis.

[0018] The above adjustment method may further include a step of illuminating an object with the illumination light via the diffraction grating and the adjustment means, and in the step of illuminating the object, the support may support the adjustment means at a position where the ratio between the intensity of the zeroth order light of the diffracted light contained in the illumination light illuminating the object and the intensity of light other than the zeroth order light becomes a predetermined value.

[0019] In the above adjusting method, the optical device may include a waveguide, and at least a portion of the diffracted light that has passed through the adjusting means may be incident on the waveguide.

[0020] In the above adjustment method, the polarization region through which the optical axis passes may be a first polarization region, and the adjustment means may have a second polarization region around the first polarization region on the plane that limits the transmission of light other than linearly polarized light in a direction different from the specified direction.

[0021] An optical device according to one aspect of this embodiment comprises a first diffraction grating that diffracts illumination light including linearly polarized light, an adjustment means that transmits at least a portion of the illumination light including the diffracted light diffracted by the first diffraction grating, and a support portion that supports the adjustment means, wherein the adjustment means has a diffraction region including a second diffraction grating on which a predetermined pattern is formed and a peripheral region surrounding the diffraction region on a plane that intersects the optical axis of the illumination light and a line parallel to the optical axis, and the support portion supports the adjustment means so that the optical axis passes through the diffraction region and so that the diffraction region can be rotated on the plane.

[0022] In the optical device, the peripheral region may be formed with a pattern different from the predetermined pattern, or may not be formed with a diffraction grating.

[0023] An optical device according to one aspect of this embodiment comprises a diffraction grating that diffracts illumination light, a first adjustment means that transmits at least a portion of the illumination light including the diffracted light diffracted by the diffraction grating, a support portion that supports the first adjustment means, and a second adjustment means downstream of the first adjustment means on the optical path of the illumination light and including a polarizing plate or a diffraction grating in a region through which a first light beam including a light beam of a main optical axis of the illumination light passes, wherein the first adjustment means has a wave plate on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis, which makes the polarization state of the first light beam different from the polarization state of a second light beam surrounding the first light beam, and the support portion supports the first adjustment means so that the wave plate can be rotated on the plane.

[0024] An optical device according to one aspect of this embodiment comprises a diffraction grating that diffracts illumination light; a first adjustment means that transmits at least a portion of the illumination light including the diffracted light diffracted by the diffraction grating; a second adjustment means downstream of the first adjustment means on the optical path of the illumination light and including a polarizing plate or a diffraction grating in a region through which a first light beam including a light beam of a main optical axis of the illumination light passes; and a support portion that supports the second adjustment means, wherein the first adjustment means has a wavelength plate on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis that makes the polarization state of the first light beam different from the polarization state of a second light beam surrounding the first light beam, and the support portion supports the second adjustment means so that the polarizing plate or the diffraction grating can be rotated on the plane.

[0025] In the above optical device, the first adjusting means may have a wave plate in a region through which the first light flux passes, and may not have a wave plate in a region through which the second light flux passes.

[0026] In the optical device described above, the first adjusting means may not have a wave plate in a region through which the first light flux passes, but may have a wave plate in a region through which the second light flux passes.

[0027] The optical device may further include a lens disposed between the diffraction grating and the first adjustment means, and the first adjustment means may be disposed on a Fourier plane of the lens.

[0028] In the above optical device, when the illumination light illuminates an object through the diffraction grating, the first adjustment means, and the second adjustment means, the support portion may support the first adjustment means at a position where the ratio between the intensity of the zeroth-order light of the diffracted light contained in the illumination light illuminating the object and the intensity of the light other than the zeroth-order light becomes a predetermined value.

[0029] In the above optical device, when the illumination light illuminates an object through the diffraction grating, the first adjustment means, and the second adjustment means, the support portion may support the second adjustment means at a position where the ratio between the intensity of the zeroth-order light of the diffracted light contained in the illumination light illuminating the object and the intensity of the light other than the zeroth-order light becomes a predetermined value.

[0030] An adjustment method according to one aspect of the present embodiment is a method for adjusting illumination light in an optical device including: a first diffraction grating that diffracts illumination light including linearly polarized light; an adjustment means that transmits at least a portion of the illumination light including diffracted light diffracted by the first diffraction grating, the adjustment means having a diffraction region including a second diffraction grating on which a predetermined pattern is formed and a peripheral region surrounding the diffraction region on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis; a support unit that supports the adjustment means; and a control unit that controls driving of the support unit, the method comprising the steps of: making the optical axis pass through the diffraction region; and supporting the adjustment means so that the diffraction region can be rotated on the plane.

[0031] An adjustment method according to one aspect of this embodiment is a method for adjusting illumination light in an optical device including: a diffraction grating that diffracts illumination light; a first adjustment means that transmits at least a portion of the illumination light including the diffracted light diffracted by the diffraction grating, the first adjustment means having a wave plate on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis, the wave plate making the polarization state of a first light beam including a light beam of a main optical axis of the illumination light different from the polarization state of a second light beam surrounding the first light beam; a support unit that supports the first adjustment means; a second adjustment means that is downstream of the first adjustment means on the optical path of the illumination light and includes a polarizing plate or a diffraction grating in a region through which the first light beam passes; and a control unit that controls driving of the support unit, the method comprising the steps of: making the main optical axis pass through the wave plate; and supporting the first adjustment means so that the wave plate can be rotated on the plane.

[0032] An adjustment method according to one aspect of the present embodiment is a method for adjusting illumination light in an optical device including: a diffraction grating that diffracts illumination light; a first adjustment means that transmits at least a portion of the illumination light including the diffracted light diffracted by the diffraction grating, the first adjustment means having a wave plate on a plane intersecting the optical axis of the illumination light and a line parallel to the optical axis, which wave plate makes the polarization state of a first light beam including a light beam of a main optical axis of the illumination light different from the polarization state of a second light beam surrounding the first light beam; a second adjustment means downstream of the first adjustment means on the optical path of the illumination light and including a polarizing plate or a diffraction grating in a region through which the first light beam passes; a support unit that supports the second adjustment means; and a control unit that controls the drive of the support unit, the method comprising the steps of: making the main optical axis pass through the wave plate; and supporting the second adjustment means so that the polarizing plate or the diffraction grating can be rotated on the plane. [Effects of the Invention]

[0033] According to the present disclosure, it is possible to provide an optical device and an adjustment method capable of adjusting the zeroth-order light in diffracted light using a diffraction grating. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 10 is a cross-sectional view illustrating an optical device according to a comparative example. [Figure 2] FIG. 10 is a plan view illustrating an adjustment unit of an optical device according to a comparative example. [Figure 3] 1 is a cross-sectional view illustrating an optical device according to a first embodiment. [Figure 4] 3 is a plan view illustrating an adjustment unit of the optical device according to the first embodiment. FIG. [Figure 5] 10 is a plan view illustrating another adjustment means of the optical device according to the first embodiment. FIG. [Figure 6] 1 is a cross-sectional view illustrating an optical device according to a first embodiment. [Figure 7] 3 is a cross-sectional view illustrating illumination light that illuminates an object in the optical device according to the first embodiment. FIG. [Figure 8]4 is a flowchart illustrating a method for adjusting illumination light in the optical device according to the first embodiment. [Figure 9] 10 is a cross-sectional view illustrating an optical device according to a first modified example of the first embodiment. [Figure 10] 10 is a cross-sectional view illustrating an optical device according to a second modification of the first embodiment. [Figure 11] 10 is a cross-sectional view illustrating an optical device according to a third modification of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description illustrates preferred embodiments of the present disclosure, and the scope of the present disclosure is not limited to the following embodiments. In the following description, components with the same reference numerals indicate substantially the same content. Hatching may be omitted to avoid cluttering the drawings.

[0036] Before describing the optical device according to the embodiment, an optical device according to a comparative example will be described. Then, the optical device according to the embodiment will be described in comparison with the optical device according to the comparative example. This will make the characteristics of the optical device according to the embodiment clearer. Note that the optical device according to the comparative example is also within the scope of the technical concept of the present disclosure.

[0037] (Comparative Example) FIG. 1 is a cross-sectional view illustrating an optical device 101 according to a comparative example. FIG. 1 also shows a schematic diagram illustrating the intensity distribution of illumination light L1. As shown in FIG. 1, the optical device 101 includes a diffraction grating 10, a lens F1, and a shielding plate 120. The optical device 101 includes a device that uses illumination light L1. The optical device 101 may be an inspection device that inspects an inspection object by illuminating the inspection object with illumination light L1. The optical device 101 may also be a review device that reviews a review object by illuminating the review object with illumination light L1. The optical device 101 is not limited to an inspection device or a review device, and may also be a manufacturing device or the like, as long as it uses illumination light L1.

[0038] The illumination light L1 may include, for example, laser light. The illumination light L1 has an optical axis C1. A cross section of the illumination light L1 perpendicular to the optical axis C1 may be circular. Here, for convenience of explanation of the optical device 101, an XYZ Cartesian coordinate system is introduced. The direction parallel to the optical axis C1 of the illumination light L1 is defined as the Z-axis direction. The plane perpendicular to the optical axis C1 of the illumination light L1 is defined as the XY plane. In this case, the illumination light L1 travels in the +Z-axis direction.

[0039] The illumination light L1 may include linearly polarized light having a vibration direction of a unidirectional electric field. For example, the illumination light L1 may include linearly polarized light having a vibration direction in the Y-axis direction. The illumination light L1 may be light obtained by converting the polarization state of laser light generated by a laser generator using a polarizing element so that it includes linearly polarized light. Note that the illumination light L1 is not limited to laser light, and may also be light obtained by converting the polarization state of light having a broad wavelength range using a polarizing element so that it includes linearly polarized light. The illumination light L1 is incident on the diffraction grating 10.

[0040] The diffraction grating 10 is, for example, plate-shaped and has a first surface 11 and a second surface 12 opposite the first surface 11. The first surface 11 of the diffraction grating 10 faces the -Z axis direction, and the second surface 12 faces the +Z axis direction. Illumination light L1 is incident on the first surface 11 of the diffraction grating 10. The diffraction grating 10 includes, for example, a two-dimensional (2D) diffraction grating. The diffraction grating 10 diffracts the illumination light L1 incident on the first surface 11, thereby emitting diffracted light LD including zero-order light, first-order light, second-order light, etc. from the second surface 12. In this way, the diffraction grating 10 diffracts the illumination light L1 including linearly polarized light. Specifically, the diffraction grating 10 diffracts the illumination light L1 incident on the first surface 11, thereby emitting the illumination light L1 including the diffracted light LD from the second surface 12.

[0041] Of the diffracted light LD, the zeroth-order light is emitted from the second surface 12 of the diffraction grating 10 in the direction of the optical axis C1 of the illumination light L1. The zeroth-order light is emitted in a direction perpendicular to the second surface 12 of the diffraction grating 10. Of the diffracted light LD, the first-order light, second-order light, etc. are emitted from the second surface 12 of the diffraction grating 10 at angles to the direction of the optical axis C1 of the illumination light L1. The diffraction grating 10 may separate the light into as many orders as possible. The diffraction grating 10 may or may not completely separate the light of adjacent orders. The skirt portions at both ends of the peaks of the light of adjacent orders may overlap and be continuous.

[0042] The illumination light L1 emitted from the diffraction grating 10 includes diffracted light LD such as zeroth-order light, first-order light, second-order light, etc. The illumination light L1 including the diffracted light LD is incident on the lens F1. The lens F1 is disposed between the diffraction grating 10 and the shielding plate 120. The lens F1 collects and transmits the incident illumination light L1. The zeroth-order light that has transmitted through the lens F1 is collected at the center of the Fourier plane FU (solid line in FIG. 1). The first-order light, second-order light, etc. are collected at positions away from the optical axis C1 on the Fourier plane FU depending on the order. In this way, the lens F1 Fourier transforms the diffracted light LD onto the Fourier plane.

[0043] Illumination light L1 including diffracted light LD forms an intensity distribution on the Fourier plane FU. For example, illumination light L1 including diffracted light LD has a portion where the intensity of zero-order light is high at the center of the pupil. Therefore, when illumination light L1 including diffracted light LD is used, the illumination conditions will differ depending on the illumination position of the diffracted light LD.

[0044] Therefore, in the optical device 101 of the comparative example, a shading plate 120 is placed at the Fourier plane FU to reduce the influence of the zeroth-order light. Therefore, the illumination light L1 transmitted through the lens F1 is incident on the shading plate 120. The shading plate 120 functions as a mechanical pupil shield. This allows the shading plate 120 to block the zeroth-order light in the diffracted light LD.

[0045] The shielding plate 120 is, for example, in the form of a plate having a first surface 121 and a second surface 122 opposite to the first surface 121. The first surface 121 of the shielding plate 120 faces the −Z axis direction, and the second surface 122 faces the +Z axis direction. The illumination light L1 including the diffracted light LD is incident on the first surface 121.

[0046] Fig. 2 is a plan view illustrating a shielding plate 120 of an optical device 101 according to a comparative example. As shown in Fig. 2, the shielding plate 120 has a hole 123 that penetrates from a first surface 121 to a second surface 122. A shielding portion 124 is disposed in the center of the hole 123.

[0047] The shielding portion 124 is, for example, cylindrical and has a central axis extending in the Z-axis direction. The shielding portion 124 shields a portion of the diffracted light LD that includes zero-order light. A connecting portion 125 is provided on the inner surface of the hole 123, extending from the inner surface of the hole 123 to the shielding portion 124. The connecting portion 125 fixes the shielding portion 124 to the inside of the hole 123. The illumination light L1 that includes the diffracted light LD passes through the inside of the hole 123 except for the shielding portion 124 and the connecting portion 125.

[0048] As described above, in the comparative example, the shielding plate 120 is used as a method for mitigating the effect of high intensity of the zero-order light. On the other hand, the disadvantages of the shielding plate 120 include blocking light other than the center, affecting transmittance and illumination conditions, and the presence of unusable central light in the illumination area of ​​the diffracted light LD.

[0049] (Embodiment 1) Next, an optical device and an adjustment method according to the first embodiment will be described. FIG. 3 is a cross-sectional view illustrating the optical device 1 according to the first embodiment. FIG. 4 is a plan view illustrating the adjustment means 20 of the optical device 1 according to the first embodiment. As shown in FIGS. 3 and 4, the optical device 1 includes a diffraction grating 10, a lens F1, the adjustment means 20, and a support portion 30. Like the optical device 101 according to the comparative example, the optical device 1 includes a device that uses illumination light L1. The illumination light L1 is incident on a first surface 11 of the diffraction grating 10.

[0050] Similar to the comparative example, the diffraction grating 10 diffracts illumination light L1 containing linearly polarized light. The illumination light L1 may be light having linear polarization in one vibration direction polarized by a known method, or may be light having linear polarization in two or more vibration directions. The diffraction grating 10 diffracts the illumination light L1 incident on the first surface 11, and emits illumination light L1 containing diffracted light LD from the second surface 12. The diffracted light LD includes light of zeroth order, first order, second order, etc. The illumination light L1 emitted from the diffraction grating 10 and containing diffracted light LD is incident on the lens F1.

[0051] The lens F1 is disposed between the diffraction grating 10 and the adjustment means 20. The optical axis of the lens F1 may coincide with the optical axis C1 of the illumination light L1. The lens F1 collects and transmits the incident illumination light L1. The zeroth-order light that has passed through the lens F1 is collected at the center of the Fourier plane FU. The first-order light, second-order light, ..., and other light are collected at positions away from the optical axis C1 on the Fourier plane FU depending on the order. In this embodiment, the illumination light L1, including the diffracted light LD that has passed through the lens F1, is incident on the adjustment means 20.

[0052] The adjustment means 20 is, for example, plate-shaped and has a first surface 21 and a second surface 22 opposite to the first surface 21. The first surface 21 of the adjustment means 20 may face the -Z axis direction, and the second surface 22 may face the +Z axis direction. The adjustment means 20 may be disposed at the Fourier plane FU of the lens F1. The adjustment means 20 may also be disposed at a position shifted from the Fourier plane FU in the direction of the optical axis C1. The illumination light L1 transmitted through the lens F1 is incident on the first surface 21 of the adjustment means 20. The adjustment means 20 may include a transparent member such as a glass plate or a quartz plate. The adjustment means 20 may be a transparent member on which a polarizing element is formed. The polarizing element transmits linearly polarized light vibrating in a predetermined direction. The polarizing element transmits illumination light L1 containing linearly polarized light depending on the vibration direction. The polarizing element includes, for example, a polarizing plate. The polarizing element is not limited to a polarizing plate, and may be, for example, a one-dimensional (1D) diffraction grating, as long as it transmits linearly polarized light.

[0053] The adjusting unit 20 has a polarizing region 23, which includes a polarizing element that limits the transmission of light other than light linearly polarized in a predetermined direction, on a plane intersecting the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1. The "plane" intersecting the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1 may be a plane perpendicular to the optical axis C1, and the adjusting unit 20 may have the polarizing region 23 on the plane perpendicular to the optical axis C1. That is, in this case, the support unit 30, which will be described later, may support the adjusting unit 20 so that the polarizing region 23 is located on a plane perpendicular to the optical axis C1. Also, the "plane" intersecting the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1 may be a plane tilted with respect to the optical axis C1, and the adjusting unit 20 may have the polarizing region 23 on a plane tilted with respect to the optical axis C1. That is, in this case, the support unit 30, which will be described later, may support the adjusting unit 20 so that the polarizing region 23 is located on a plane tilted with respect to the optical axis C1. The "plane" intersecting the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1 may be referred to as a plane viewed from the direction of the optical axis C1 of the illumination light L1, as appropriate. The adjustment means 20 may further have a transmission region 24 surrounding the polarization region 23 when viewed from the direction of the optical axis C1 of the illumination light L1. The transmission region 24 transmits the illumination light L1, which includes light linearly polarized in a predetermined direction and light linearly polarized in a direction other than the predetermined direction. The adjustment means 20 transmits at least a portion of the illumination light L1, which includes diffracted light LD diffracted by the diffraction grating 10.

[0054] The polarizing element in the polarization region 23 rotates around the optical axis C1 as a rotation axis by driving the support unit 30. Specifically, the entire adjustment unit 20 including the polarization region 23 rotates around the optical axis C1 as a rotation axis by driving the support unit 30. This allows the adjustment unit 20 to adjust the intensity of the illumination light L1 that passes through the polarization region 23.

[0055] For example, when the illumination light L1 includes linearly polarized light having a vibration direction in the Y-axis direction, the vibration direction of the linearly polarized light transmitted by the polarizing element in the polarization region 23 can be set to the Y-axis direction, allowing the illumination light L1 to pass through the polarization region 23. On the other hand, when the illumination light L1 includes linearly polarized light having a vibration direction in the Y-axis direction, the vibration direction of the linearly polarized light transmitted by the polarizing element in the polarization region 23 can be set to the X-axis direction, preventing the illumination light L1 from passing through the polarization region 23. When the illumination light L1 includes linearly polarized light having a vibration direction in the Y-axis direction, the vibration direction of the linearly polarized light transmitted by the polarizing element in the polarization region 23 can be set to a direction intersecting the X-axis and Y-axis directions, allowing the proportion of the illumination light L1 that passes through the polarization region 23 to be adjusted.

[0056] 5 is a plan view illustrating another adjustment unit 20a of the optical device 1 according to the first embodiment. As shown in FIG. 5, the adjustment unit 20a may have a polarization region 25 around the polarization region 23 when viewed from the direction of the optical axis C1 of the illumination light L1. That is, the polarization region 25 may be located between the polarization region 23 and the transmission region 24. The polarization region 25 transmits linearly polarized light having a vibration direction different from the predetermined vibration direction transmitted by the polarizing element of the polarization region 23 through which the optical axis C1 of the illumination light L1 passes. This configuration can mitigate changes in the boundary between the polarization region 23 and the transmission region 24.

[0057] For example, by making the vibration direction of the linearly polarized light of illumination light L1 transmitted by the polarizing element of polarizing region 25 different from the vibration direction of the linearly polarized light of illumination light L1 transmitted by the polarizing element of polarizing region 23, it is possible to mitigate changes in the boundary between polarizing region 23 and transmissive region 24. Furthermore, multiple polarizing regions 25 may be provided between polarizing region 23 and transmissive region 24. The multiple polarizing regions 25 may gradually change their vibration direction from the vibration direction of polarizing region 23 to the vibration direction of illumination light L1 depending on whether they are located closer to the polarizing region 23 or the transmissive region 24. This further mitigates changes in the boundary between polarizing region 23 and transmissive region 24.

[0058] The support unit 30 supports the adjustment unit 20. For example, the support unit 30 supports the adjustment unit 20 by being connected to the lower part of the adjustment unit 20. The support unit 30 supports the adjustment unit 20 so that the optical axis C1 of the illumination light L1 passes through the polarization region 23. The support unit 30 also supports the adjustment unit 20 so that the polarization region 23 is rotatable on the plane on which the polarization region 23 is formed. The support unit 30 may support the adjustment unit 20 so that it is rotatable about an axis that is included in the polarization region 23 (for example, the optical axis C1 of the illumination light L1). For example, the support unit 30 includes a drive unit, and by driving the drive unit, the entire adjustment unit 20 including the polarization region 23 is rotated. In addition, the support part 30 supporting the polarization region 23 rotatably on the plane on which the polarization region 23 is formed also includes temporarily detaching (releasing) the adjustment means 20 from the support part 30, changing the posture of the adjustment means 20 so that the angle between the line connecting the point where the optical axis C1 and the polarization region 23 intersect and the line connecting the point where the line parallel to the optical axis C1 and the polarization region 23 intersects, and the vibration direction (predetermined direction) of the linearly polarized light transmitted by the polarizing element in the polarization region 23 changes before and after detachment, and then supporting the adjustment means 20 again with the support part 30.

[0059] The support unit 30 may displace the position of the adjustment unit 20 in the direction of the optical axis C1. For example, the support unit 30 displaces the position of the adjustment unit 20 in the direction of the optical axis C1 by driving the drive unit. When the illumination light L1 illuminates the object via the diffraction grating 10 and the adjustment unit 20, the support unit 30 adjusts the rotation of the polarization region 23 around the optical axis C1 and the position of the polarization region 23 in the direction of the optical axis C1 so that the ratio between the intensity of the zeroth-order light of the diffracted light contained in the illumination light L1 illuminating the object and the intensity of the light other than the zeroth-order light becomes a predetermined value. For example, the support unit 30 may adjust the rotation and position of the polarization region 23 so that the intensity of the zeroth-order light and the intensity of the light other than the zeroth-order light become approximately uniform.

[0060] Fig. 6 is a cross-sectional view illustrating the optical device 1 according to embodiment 1. Fig. 7 is a cross-sectional view illustrating illumination light L1 that illuminates an object 60 in the optical device 1 according to embodiment 1. As shown in Figs. 6 and 7, the optical device 1 may further include lenses F2 to F3, an objective lens F4, a waveguide 40, and a control unit 50 in addition to the above-mentioned members.

[0061] The illumination light L1 emitted from the second surface 22 of the adjustment means 20 is incident on the lens F2. The lens F2 collects and transmits the illumination light L1. The illumination light L1 that has passed through the lens F2 is incident on the waveguide 40. In this way, at least a portion of the illumination light L1 that has passed through the adjustment means 20 is transmitted through the lens F2 and enters the waveguide 40.

[0062] The waveguide 40 has a bottom surface 41 and a bottom surface 42 and is a rectangular column-shaped member extending in the Z-axis direction. Therefore, the waveguide 40 may also be called a rectangular rod. The waveguide 40 is disposed with the bottom surface 41 facing the -Z-axis direction and the bottom surface 42 facing the +Z-axis direction. The illumination light L1 transmitted through the lens F2 is incident on the bottom surface 41 of the waveguide 40. The illumination light L1 that enters the waveguide 40 travels through the waveguide 40 in the +Z-axis direction and exits from the bottom surface 42. The NA of the illumination light L1 entering the waveguide 40 may be the same as the NA of the illumination light L1 that exits the waveguide 40. The waveguide 40 homogenizes the intensity profile of the illumination light L1.

[0063] The illumination light L1 incident on the diffraction grating 10 and the illumination light L1 incident on the waveguide 40 are conjugate with the lenses F1 and F2. Therefore, the cross sections of the illumination light L1 incident on the diffraction grating 10 and the illumination light L1 incident on the waveguide 40, which are perpendicular to the optical axis C1, are circular. The waveguide 40 has a homogenized function for homogenizing the illumination light L1. Specifically, the illumination light L1 incident on the bottom surface 41 of the waveguide 40 with a circular cross section exits from the bottom surface 42 of the waveguide 40 with a rectangular cross section. The illumination light L1 exiting the waveguide 40 and the illumination light L1 illuminating the object 60 are conjugate with the lenses F3 and F4. Therefore, the cross sections of the illumination light L1 exiting the waveguide 40 and the illumination light L1 illuminating the object 60, which are perpendicular to the optical axis C1, are rectangular.

[0064] The object 60 is an object illuminated with the illumination light L1. When the optical device 1 is an inspection device, the object 60 is an inspection object. When the optical device 1 is a review device, the object 60 is a review object. The object 60 includes, for example, a mask.

[0065] When the illumination light L1 illuminates the object 60 via the diffraction grating 10 and the adjusting means 20, the size and intensity profile on the pupil of the objective lens F4 that focuses the illumination light L1 on the object 60 may be set by the lenses F1 and F2 before the illumination light L1 enters the waveguide 40. In this case, the waveguide 40 can homogenize the intensity profile of the illumination light L1 that illuminates the object 60.

[0066] The control unit 50 controls the driving of the support unit 30. The control unit 50 is connected to the support unit 30 via a wired or wireless communication line in a state where information can be transmitted between the control unit 50 and the support unit 30. The control unit 50 may also be connected to a sensor, such as a photometer, that detects the intensity profile of the illumination light L1 in a state where information can be transmitted between the control unit 50 and the support unit 30 via a wired or wireless communication line. Based on information acquired from the sensor or the like, the control unit 50 causes the support unit 30 to support the adjustment unit 20 so that the optical axis C1 of the illumination light L1 passes through the polarization region 23. Based on information acquired from the sensor or the like, the control unit 50 also causes the support unit 30 to rotate the polarization region 23 around the optical axis C1 of the illumination light L1 as the rotation axis. Based on information acquired from the sensor or the like, the control unit 50 also causes the support unit 30 to move the adjustment unit 20 in the direction of the optical axis C1 of the illumination light L1.

[0067] Next, a method for adjusting the illumination light L1 in the optical device 1 of this embodiment will be described. The method for adjusting the illumination light L1 includes a method for adjusting the intensity of the illumination light L1. The method for adjusting the illumination light L1 may also include a method for adjusting the polarization state of the illumination light L1. FIG. 8 is a flowchart illustrating a method for adjusting the illumination light L1 in the optical device 1 according to the first embodiment. As shown in FIG. 8, the adjustment method of this embodiment may include steps S11 and S12. Furthermore, the adjustment method of this embodiment may further include at least one of steps S13 and S14 in addition to steps S11 and S12.

[0068] In step S11, the optical axis C1 of the illumination light L1 is made to pass through the polarization region 23 of the adjustment means 20. For example, the control unit 50 causes the support unit 30 to support the adjustment means 20 so that the optical axis C1 of the illumination light L1 passes through the polarization region 23. For example, the control unit 50 may move the position of the support unit 30 so that the optical axis C1 of the illumination light L1 passes through the polarization region 23, based on the intensity distribution of the illumination light L1 acquired from a sensor or the like.

[0069] In step S12, the adjustment unit 20 is supported so that the polarization region 23 can rotate on a plane intersecting the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1. For example, the control unit 50 causes the support unit 30 to rotate the polarization region 23 around the optical axis C1 of the illumination light L1 as the rotation axis. For example, the control unit 50 may cause the support unit 30 to rotate the polarization region 23 around the optical axis C1 of the illumination light L1 as the rotation axis based on the intensity distribution of the illumination light L1 acquired from a sensor or the like.

[0070] In step S13, the control unit 50 causes the support unit 30 to displace the position of the adjustment unit 20 in the direction of the optical axis C1 of the illumination light L1. For example, the control unit 50 may cause the support unit 30 to move the position of the adjustment unit 20 in the direction of the optical axis C1 based on the intensity distribution of the illumination light L1 acquired from a sensor or the like.

[0071] In step S14, the control unit 50 controls the illumination light L1 to illuminate the object 60 via the diffraction grating 10 and the adjustment unit 20. In step S14, the control unit 50 controls the support unit 30 to adjust the rotation of the polarization region 23 around the optical axis C1 and the position of the polarization region 23 in the direction of the optical axis C1 so that the ratio between the intensity of the zero-order light and the intensity of the light other than the zero-order light of the diffracted light LD contained in the illumination light L1 illuminating the object 60 becomes a predetermined value. For example, the control unit 50 adjusts the rotation of the polarization region 23 around the optical axis C1 and the position of the polarization region 23 in the direction of the optical axis C1 so that the intensity of the zero-order light and the intensity of the light other than the zero-order light become approximately uniform. In this manner, the control unit 50 adjusts the illumination light L1 in the optical device 1.

[0072] Next, the effects of this embodiment will be described. In the optical device 1 of this embodiment, the adjustment means 20 has a polarization region 23 that transmits linearly polarized light in a predetermined direction. Therefore, the optical device 1 can adjust the intensity of the illumination light L1, including linearly polarized light, that passes through the adjustment means 20 by rotating the polarization region 23 using the support part 30. This allows the optical device 1 to arbitrarily adjust the intensity of the zero-order light in the diffracted light LD contained in the illumination light L1.

[0073] When adjusting the intensity of the zero-order light, the polarization region 23 may completely block the zero-order light or transmit the zero-order light so that the ratio of the intensity of the zero-order light to the intensity of light other than the zero-order light is a predetermined value. With this configuration, the optical device 1 can use the zero-order light whose intensity has been adjusted, thereby making it possible to use the illumination light L1 including the diffracted light LD without waste. In other words, the entire cross section of the illumination light L1 perpendicular to the optical axis C1 can be used.

[0074] In this way, compared to the comparative example, this embodiment can use the central portion including the zero-order light in the illumination light L1, thereby reducing the influence on the transmittance and illumination conditions.

[0075] Furthermore, the optical device 1 may illuminate the object 60 using a waveguide 40. By passing the illumination light L1 through the waveguide 40, the illumination light L1 can be made uniform. Furthermore, by forming the cross-sectional shape of the waveguide 40 into a desired shape, the cross-sectional shape of the illumination light L1 can be formed into a desired shape. This allows, for example, the illumination area of ​​the object 60 to be formed into a desired shape, thereby improving the flexibility of use of the optical device 1.

[0076] By forming the polarizing region 25 around the polarizing region 23, it is possible to mitigate boundary changes in the profile of the illumination light L1.

[0077] (Variation 1) Next, optical devices according to Modifications 1 to 3 will be described. The optical devices according to Modifications 1 to 3 may be provided with a plurality of locations for arranging the adjustment means. Modification 1 shows an example in which the adjustment means is arranged in one location 71, while Modifications 2 and 3 show examples in which the adjustment means is arranged in two locations 71 and 72.

[0078] 9 is a cross-sectional view illustrating an optical device 1a according to a first modification of the first embodiment. As shown in FIG. 9, the optical device 1a includes a diffraction grating 10, an adjustment means 20b, and a support portion 30. The diffraction grating 10 diffracts illumination light L1 including linearly polarized light. The adjustment means 20b transmits at least a portion of the illumination light L1 including diffracted light LD diffracted by the diffraction grating 10. The support portion 30 supports the adjustment means 20b. The optical device 1a includes the adjustment means 20b at an arrangement location 71. The arrangement location 71 is, for example, the Fourier plane FU of the lens F1.

[0079] In this modified example, the adjustment unit 20b has a diffraction region 26 and a peripheral region 27. The diffraction region 26 includes a diffraction grating having a predetermined pattern formed on a plane in the adjustment unit 20b that intersects with the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1. The peripheral region 27 is arranged in the adjustment unit 20b so as to surround the diffraction region 26 on that plane. A diffraction grating having a pattern different from the predetermined pattern of the diffraction region 26 may be formed in the peripheral region 27. Alternatively, a diffraction grating may not be formed in the peripheral region 27. The adjustment unit 20b is rotatably supported by a support unit 30. The support unit 30 supports the adjustment unit 20b so that the optical axis C1 of the illumination light L1 passes through the diffraction region 26 and so that the diffraction region 26 can be rotatable on that plane.

[0080] This modification can improve the degree of freedom in designing the optical device 1a in addition to the effects of the above-described embodiment 1. Configurations (e.g., lens F1, etc.) and effects other than those described above in this modification are included in the description of embodiment 1.

[0081] (Variation 2) Fig. 10 is a cross-sectional view illustrating an optical device 1b according to Modification 2 of Embodiment 1. As shown in Fig. 10, the optical device 1b includes a diffraction grating 10, a first adjustment unit 20c, a first support unit 30c, a second adjustment unit 20d, and a second support unit 30d. In this modification, the diffraction grating 10 diffracts the illumination light L1.

[0082] The first adjustment means 20c is disposed at an arrangement location 71. The first adjustment means 20c transmits at least a portion of the illumination light L1, which includes the diffracted light LD diffracted by the diffraction grating 10. The first adjustment means 20c has a wave plate 28. The wave plate 28 makes the polarization state of a first light beam, which includes the light beam of the main optical axis C1 of the illumination light L1, different from the polarization state of a second light beam surrounding the first light beam, on a plane intersecting the optical axis C1 of the illumination light L1 and a line parallel to the optical axis C1.

[0083] The first support portion 30c supports the first adjustment means 20c. The first support portion 30c supports the first adjustment means 20c so that the wave plate 28 can be rotated on the plane.

[0084] The second adjustment means 20d is disposed at an arrangement location 72. The arrangement location 72 is located downstream of the arrangement location 71 on the optical path of the illumination light L1. Therefore, the second adjustment means 20d is located downstream of the first adjustment means 20c on the optical path of the illumination light L1. Note that the arrangement location 72 includes a position where the main optical axis C1 of the illumination light L1 hits the center of the second adjustment means 20d. For example, the arrangement location 72 may be a position where collimated light that has passed through the first adjustment means 20c hits.

[0085] The second adjustment means 20d includes a member 29, which is either a polarizing plate or a diffraction grating, in a region through which the first light flux, including the light flux of the main optical axis C1 of the illumination light L1, passes. The member 29 may be arranged over the entire plane of the second adjustment means 20d or only in the central portion, as long as it is arranged in at least a region through which the first light flux passes, such as the center. The portions of the second adjustment means 20d other than the member 29 may include a transparent member.

[0086] The second support portion 30d supports the second adjustment means 20d. The second support portion 30d may or may not support the second adjustment means 20d rotatably on the plane.

[0087] According to this modification, in addition to the effects of the above-described embodiment 1, it is possible to further improve the degree of freedom in designing the optical device 1b. Configurations and effects of this modification other than those described above are included in the descriptions of embodiment 1 and modification 1.

[0088] (Variation 3) 11 is a cross-sectional view illustrating an optical device 1c according to Modification 3 of Embodiment 1. As shown in Fig. 11, optical device 1c includes a diffraction grating 10, a first adjustment unit 20c, a first support unit 30c, a second adjustment unit 20d, and a second support unit 30d. The configuration of this modification differs from Modification 2 in that first support unit 30c does not rotatably support first adjustment unit 20c, and second support unit 30d rotatably supports second adjustment unit 20d.

[0089] According to this modification, in addition to the effects of the above-described embodiment 1, it is possible to further improve the degree of freedom in designing the optical device 1c. Configurations and effects of this modification other than those described above are included in the descriptions of embodiment 1 and modifications 1 and 2.

[0090] Although the embodiments of the present disclosure have been described above, the present disclosure includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-described embodiments. Furthermore, combinations of the configurations of embodiment 1 are also within the scope of the technical concept of the present disclosure. [Explanation of symbols]

[0091] 1, 1a, 1b, 1c, 101 optical equipment 10 Diffraction Grating 11 Page 1 12 Side 2 20, 20a, 20b adjustment means 20c First adjustment means 20d Second adjustment means 21 Page 1 22 Side 2 23 Polarization region 24 Transparent area 25 Polarization region 26 Diffraction Area 27 Surrounding Areas 28 Wave plate 29 Components 30 Support part 40 Waveguide 41, 42 bottom 50 control section 60 Objects 71 Location 72 Location 120 Shielding plate 121 Page 1 122 2nd page 123 holes 124 Shielding part 125 Connection C1 optical axis F1, F2, F3 lenses F4 objective lens FU Fourier surface L1 illumination light LD diffracted light

Claims

1. a diffraction grating that diffracts illumination light including linearly polarized light; an adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the diffraction grating; a support portion that supports the adjustment means; Equipped with the adjusting means has a polarizing region on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis, the polarizing region including a polarizing element that limits transmission of light other than linearly polarized light in a predetermined direction; The support portion is supporting the adjusting means so that the optical axis passes through the polarizing region and so that the polarizing region can be rotated on the plane; optical equipment.

2. the adjusting means further includes a transmission area on the plane surrounding the polarizing area; the transmission region transmits light other than the light linearly polarized in the predetermined direction through the polarization region; 10. The optical device of claim 1.

3. a lens disposed between the diffraction grating and the adjusting means; The adjustment means is disposed in the Fourier plane of the lens.

3. The optical device according to claim 1.

4. the support portion supports the adjustment means so that the position of the adjustment means can be displaced in the direction of the optical axis.

3. The optical device according to claim 1.

5. When the illumination light illuminates an object via the diffraction grating and the adjusting means, the support portion supports the adjustment means at a position where a ratio between an intensity of a zero-order light of the diffracted light contained in the illumination light that illuminates the object and an intensity of light other than the zero-order light becomes a predetermined value.

3. The optical device according to claim 1.

6. further comprising a waveguide; At least a part of the illumination light transmitted through the adjusting means is incident on the waveguide.

3. The optical device according to claim 1.

7. the polarization region through which the optical axis passes is a first polarization region, the adjusting means has a second polarizing region around the first polarizing region on the plane, the second polarizing region restricting transmission of light other than linearly polarized light in a direction different from the predetermined direction; 10. The optical device of claim 1.

8. the adjusting means further includes a transmission region in the plane surrounding the second polarizing region; the transmission region transmits light other than linearly polarized light in the predetermined direction through the first polarization region, and transmits light other than linearly polarized light in a direction different from the predetermined direction through the second polarization region; 8. The optical device according to claim 7.

9. a diffraction grating that diffracts illumination light including linearly polarized light; an adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the diffraction grating, the adjusting means having a polarizing region on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis, the polarizing region including a polarizing element that limits transmission of light other than linearly polarized light in a predetermined direction; a support portion that supports the adjustment means; a control unit that controls the driving of the support unit; A method for adjusting illumination light in an optical device comprising: directing the optical axis through the polarizing region; supporting the adjusting means so that the polarizing region can be rotated in the plane; An adjustment method comprising:

10. the adjusting means further includes a transmission area on the plane surrounding the polarizing area; the transmission region transmits light other than the light linearly polarized in the predetermined direction through the polarization region; The adjusting method according to claim 9.

11. the optical device includes a lens disposed between the diffraction grating and the adjusting means; The adjustment means is disposed in the Fourier plane of the lens. The adjusting method according to claim 9 or 10.

12. The method further includes a step of supporting the adjustment means on the support portion so that the position of the adjustment means can be displaced in the direction of the optical axis. The adjusting method according to claim 9 or 10.

13. The method further includes a step of illuminating an object with the illumination light via the diffraction grating and the adjusting means, In the step of illuminating the object, the adjustment means is supported by the support portion at a position where a ratio between an intensity of a zero-order light of the diffracted light contained in the illumination light illuminating the object and an intensity of light other than the zero-order light becomes a predetermined value. The adjusting method according to claim 9 or 10.

14. the optical device comprises a waveguide; At least a part of the diffracted light transmitted through the adjusting means is incident on the waveguide. The adjusting method according to claim 9 or 10.

15. the polarization region through which the optical axis passes is a first polarization region, the adjusting means has a second polarizing region around the first polarizing region on the plane, the second polarizing region restricting transmission of light other than linearly polarized light in a direction different from the predetermined direction; The adjusting method according to claim 9 or 10.

16. a first diffraction grating that diffracts illumination light including linearly polarized light; an adjusting means for transmitting at least a portion of the illumination light including the diffracted light diffracted by the first diffraction grating; a support portion that supports the adjustment means; Equipped with the adjusting means has a diffraction region including a second diffraction grating on which a predetermined pattern is formed, and a peripheral region surrounding the diffraction region, on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis; The support portion is the adjusting means is supported so that the optical axis passes through the diffractive region and so that the diffractive region can be rotated on the plane. optical equipment.

17. The optical device according to claim 16 , wherein the peripheral region has a pattern different from the predetermined pattern or does not have a diffraction grating formed therein.

18. a diffraction grating that diffracts illumination light; a first adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the diffraction grating; a support portion that supports the first adjustment means; a second adjustment means that is downstream of the first adjustment means on the optical path of the illumination light and includes a polarizing plate or a diffraction grating in a region through which a first light flux including a light flux of a main optical axis of the illumination light passes; Equipped with the first adjustment means has a wave plate on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis, the wave plate making a polarization state of the first light beam different from a polarization state of a second light beam around the first light beam; the support portion supports the first adjustment means so as to be able to rotate the wave plate on the plane. optical equipment.

19. a diffraction grating that diffracts illumination light; a first adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the diffraction grating; a second adjustment means that is downstream of the first adjustment means on the optical path of the illumination light and includes a polarizing plate or a diffraction grating in a region through which a first light flux including a light flux of a main optical axis of the illumination light passes; a support portion that supports the second adjustment means; Equipped with the first adjustment means has a wave plate on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis, the wave plate making a polarization state of the first light beam different from a polarization state of a second light beam around the first light beam; the support portion supports the second adjustment means so as to rotate the polarizing plate or the diffraction grating on the plane. optical equipment.

20. 20. The optical device according to claim 18, wherein the first adjusting means has a wave plate in a region through which the first light beam passes, and does not have a wave plate in a region through which the second light beam passes.

21. 20. The optical device according to claim 18, wherein the first adjusting means does not have a wave plate in a region through which the first light beam passes, but has a wave plate in a region through which the second light beam passes.

22. a lens disposed between the diffraction grating and the first adjustment means; The first adjustment means is disposed in the Fourier plane of the lens.

20. An optical device according to claim 18 or 19.

23. When the illumination light illuminates an object via the diffraction grating, the first adjustment means, and the second adjustment means, 19. The optical device according to claim 18, wherein the support portion supports the first adjustment means at a position where a ratio between the intensity of the zeroth order light of the diffracted light contained in the illumination light that illuminates the object and the intensity of light other than the zeroth order light becomes a predetermined value.

24. When the illumination light illuminates the object via the diffraction grating, the first adjustment means, and the second adjustment means, 20. The optical device according to claim 19, wherein the support portion supports the second adjustment means at a position where the ratio between the intensity of the zeroth order light of the diffracted light contained in the illumination light that illuminates the object and the intensity of the light other than the zeroth order light becomes a predetermined value.

25. a first diffraction grating that diffracts illumination light including linearly polarized light; an adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the first diffraction grating, the adjusting means having a diffraction region including a second diffraction grating on which a predetermined pattern is formed, and a peripheral region surrounding the diffraction region, on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis; a support portion that supports the adjustment means; a control unit that controls the driving of the support unit; A method for adjusting illumination light in an optical device comprising: directing the optical axis through the diffractive region; supporting the adjusting means so that the diffractive region is rotatable on the plane; An adjustment method comprising:

26. a diffraction grating that diffracts illumination light; a first adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the diffraction grating, the first adjusting means having a wave plate on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis, the wave plate making a polarization state of a first light beam including a light beam of a main optical axis of the illumination light different from a polarization state of a second light beam surrounding the first light beam; a support portion that supports the first adjustment means; a second adjustment means that is downstream of the first adjustment means on the optical path of the illumination light and includes a polarizing plate or a diffraction grating in a region through which the first light flux passes; a control unit that controls the driving of the support unit; A method for adjusting illumination light in an optical device comprising: directing the principal optical axis through the wave plate; supporting the first adjustment means so that the wave plate can be rotated on the plane; An adjustment method comprising:

27. a diffraction grating that diffracts illumination light; a first adjusting means for transmitting at least a portion of the illumination light including diffracted light diffracted by the diffraction grating, the first adjusting means having a wave plate on a plane intersecting an optical axis of the illumination light and a line parallel to the optical axis, the wave plate making a polarization state of a first light beam including a light beam of a main optical axis of the illumination light different from a polarization state of a second light beam surrounding the first light beam; a second adjustment means that is downstream of the first adjustment means on the optical path of the illumination light and includes a polarizing plate or a diffraction grating in a region through which the first light flux passes; a support portion that supports the second adjustment means; a control unit that controls the driving of the support unit; A method for adjusting illumination light in an optical device comprising: directing the principal optical axis through the wave plate; supporting the second adjustment means so that the polarizing plate or the diffraction grating can be rotated on the plane; An adjustment method comprising:

Images