Light beam scanning device, optical characteristic measurement device, light beam scanning method, and optical characteristic measurement method

Abstract

The present invention is provided with a first scanning mirror, a second scanning mirror, a first mirror rotation mechanism, and a first movement mechanism. An object is irradiated with a light beam two-dimensionally scanned by the first scanning mirror and the second scanning mirror. The first mirror rotation mechanism is capable of changing the orientation of the first scanning mirror. The first movement mechanism is capable of changing a first position of the first scanning mirror. The first position of the first scanning mirror is changed according to the orientation of the first scanning mirror so that, regardless of the orientation of the first scanning mirror, a light beam reflected by the first scanning mirror passes through a reference position located between the first scanning mirror and the second scanning mirror.

Description

Optical beam scanning device, optical property measuring device, optical beam scanning method, and optical property measuring method

[0001] The present disclosure relates to an optical beam scanning device, an optical property measuring device, an optical beam scanning method, and an optical property measuring method.

[0002] Japanese Patent Application Laid-Open No. 2010-185803 (Patent Document 1) discloses a wavefront aberration measuring device including a first stage, a light source, a condenser lens, a rotary stage, a goniometric stage, a second stage, and a Shack-Hartmann sensor supported by the second stage. The first stage is movable in at least one axial direction. The light source and the condenser lens are mounted on the first stage. The rotary stage holds the test lens. The second stage is supported by the goniometric stage and is movable in at least two axial directions. While controlling the first stage, the rotary stage, the second stage, and the goniometric stage, the Shack-Hartmann sensor detects the wavefront of light emitted from the light source and transmitted through the test lens.

[0003] Japanese Patent Application Laid-Open No. 2010-185803

[0004] The optical beam scanning device of the present disclosure includes a first scanning mirror, a second scanning mirror, a first mirror rotation mechanism, and a first movement mechanism. The first scanning mirror can scan an optical beam. The second scanning mirror can scan the optical beam scanned by the first scanning mirror. The object is irradiated with an optical beam two-dimensionally scanned by the first scanning mirror and the second scanning mirror. The first mirror rotation mechanism can change the orientation of the first scanning mirror. The first movement mechanism can change the first position of the first scanning mirror. Regardless of the orientation of the first scanning mirror, the first position of the first scanning mirror is changed according to the orientation of the first scanning mirror so that the optical beam reflected by the first scanning mirror passes through a reference position between the first scanning mirror and the second scanning mirror.

[0005] Figure 1 is a schematic perspective view of the light beam scanning device and optical property measurement device of Embodiment 1. Figure 2 is a control block diagram of the light beam scanning device and optical property measurement device of Embodiment 1. Figure 3 is a schematic perspective view of the light beam scanning device and optical property measurement device of Embodiment 2. Figure 4 is a control block diagram of the light beam scanning device and optical property measurement device of Embodiment 2. Figure 5 is a schematic perspective view of the light beam scanning device and optical property measurement device of Embodiment 3. Figure 6 is a control block diagram of the light beam scanning device and optical property measurement device of Embodiment 3. Figure 7 is a schematic perspective view of the light beam scanning device and optical property measurement device of Embodiment 4. Figure 8 is a control block diagram of the light beam scanning device and optical property measurement device of Embodiments 4 and 5. Figure 9 is a schematic perspective view of the light beam scanning device and optical property measurement device of Embodiment 5. Figure 10 is a schematic perspective view of the light beam scanning device and optical property measurement device of Embodiment 6. Figure 11 is a control block diagram of the light beam scanning device and optical property measurement device of Embodiment 6.

[0006] [Problems this disclosure aims to solve] The first objective of this disclosure is to provide an optical beam scanning device and an optical beam scanning method that can scan an object with a wider range of specifications using an optical beam similar to the optical beam output from an optical beam scanning device included in a device to which the object is applied. The second objective of this disclosure is to provide an optical property measuring device and an optical property measuring method that can measure the optical properties of an object with a wider range of specifications using an optical beam similar to the optical beam output from an optical beam scanning device included in a device to which the object is applied.

[0007] [Effects of the Disclosure] The optical beam scanning apparatus and optical beam scanning method of the Disclosure enable scanning of objects with a wider range of specifications using an optical beam similar to the optical beam output from an optical beam scanning apparatus included in the apparatus to which the object is applied. The optical property measuring apparatus and optical property measuring method of the Disclosure enable measuring the optical properties of objects with a wider range of specifications using an optical beam similar to the optical beam output from an optical beam scanning apparatus included in the apparatus to which the object is applied.

[0008] [Summary of Embodiments] First, embodiments of the present disclosure will be listed and described.

[0009] (1) The optical beam scanning apparatus of the present disclosure comprises a first scanning mirror, a second scanning mirror, a first mirror rotation mechanism, and a first moving mechanism. The first scanning mirror can scan an optical beam. The second scanning mirror can scan the optical beam scanned by the first scanning mirror. An object is illuminated by an optical beam that is scanned two-dimensionally by the first scanning mirror and the second scanning mirror. The first mirror rotation mechanism can change the orientation of the first scanning mirror. The first moving mechanism can change the first position of the first scanning mirror. Regardless of the orientation of the first scanning mirror, the first position of the first scanning mirror is changed so that the optical beam reflected by the first scanning mirror passes through a reference position located between the first scanning mirror and the second scanning mirror.

[0010] The object is illuminated with a light beam that is scanned two-dimensionally by a first scanning mirror and a second scanning mirror. Furthermore, regardless of the orientation of the first scanning mirror, the first position of the first scanning mirror is changed according to the orientation of the first scanning mirror so that the light beam reflected by the first scanning mirror passes through a reference position. Therefore, optically, the first scanning mirror can be considered to be at the reference position, while in reality, the first scanning mirror can be positioned further away from the second scanning mirror and the object. Even if the size of the first and second scanning mirrors is large relative to the distance between the second scanning mirror and the object, and the distance between the first and second scanning mirrors as specified in the object's specifications, mechanical interference between two of the first, second, and object can be prevented. For a wider range of object specifications, it becomes possible to scan with a light beam similar to the light beam output from a light beam scanning device included in the device to which the object is applied (e.g., a laser processing device).

[0011] (2) The optical beam scanning device according to (1) above further comprises a controller. The controller controls the first moving mechanism according to the orientation of the first scanning mirror so that the optical beam reflected by the first scanning mirror passes through a reference position, regardless of the orientation of the first scanning mirror.

[0012] Therefore, the first position of the first scanning mirror is automatically changed according to the orientation of the first scanning mirror so that the light beam reflected by the first scanning mirror passes through the reference position.

[0013] (3) In the optical beam scanning apparatus described in (1) or (2) above, the reference position is closer to the second scanning mirror than to the first scanning mirror.

[0014] Therefore, even if the scanning mirror distance specified in the object's specifications is short, it becomes possible to scan the object with a light beam. This makes it possible to scan objects with a wider range of specifications with a light beam.

[0015] (4) The optical beam scanning device according to any of (1) to (3) above further comprises a second moving mechanism capable of adjusting the second position of the object. By adjusting the second position, the distance between the second scanning mirror and the object is adjusted.

[0016] Therefore, the distance between the second scanning mirror and the object can be adjusted according to the object's specifications. This makes it possible to scan the light beam over a wider range of objects.

[0017] (5) The optical beam scanning device according to any of (1) to (4) above further comprises a third moving mechanism that can change the third position of the second scanning mirror. The second scanning mirror includes a plurality of mirrors of different sizes. The third position of the second scanning mirror is changed so that the optical beam is scanned by one of the plurality of mirrors.

[0018] If the distance between the second scanning mirror and the object must be reduced according to the object's specifications, the light beam can be scanned with a smaller mirror. This prevents the second scanning mirror from mechanically interfering with the object. This makes it possible to scan the light beam over a wider range of object specifications.

[0019] (6) The optical beam scanning apparatus according to any of (1) to (3) above further comprises an optical path length adjuster located in the optical path of the optical beam incident on the first scanning mirror. The optical path length adjuster can adjust the optical path length of the optical beam incident on the first scanning mirror so that the optical path length of the optical beam from the incident end of the optical path length adjuster to the reference position remains constant, regardless of the first position of the first scanning mirror.

[0020] Therefore, even if the light beam spreads as it enters the light beam scanning device, the beam diameter of the light beam at the reference position can be kept constant. The optical properties of the object can be measured more accurately.

[0021] (7) The optical property measuring device of the present disclosure comprises a light beam scanning device according to any of (1) to (6) above, a light source capable of emitting a light beam, and a photodetector capable of detecting a light beam that has been scanned two-dimensionally by a first scanning mirror and a second scanning mirror and has passed through an object.

[0022] Therefore, the optical property measuring device of this disclosure enables the measurement of the optical properties of a wider range of objects using a light beam similar to the light beam output from a light beam scanning device included in the device to which the object is applied.

[0023] (8) The optical property measuring device according to (7) above further comprises a beam selector. The light source includes a first light source capable of emitting a first light beam having a first wavelength and a second light source capable of emitting a second light beam having a second wavelength different from the first wavelength. The beam selector causes either the first light beam or the second light beam to be incident on the first scanning mirror as a light beam.

[0024] Therefore, a light beam having a wavelength specified in the specifications of each object can be irradiated onto each object. The optical property measuring device makes it possible to measure the optical properties of objects with a wider range of specifications.

[0025] (9) In the optical property measuring device described in (7) or (8) above, the photodetector is a wavefront sensor that detects the wavefront of the light beam that has passed through the object.

[0026] Therefore, it becomes possible to measure the optical properties (e.g., aberrations) of objects with a wider range of specifications.

[0027] (10) In the optical property measuring device relating to any of (7) to (9) above, the object is an fθ lens.

[0028] Therefore, it becomes possible to measure the optical characteristics (e.g., aberrations) of fθ lenses with a wider range of specifications.

[0029] (11) The optical beam scanning method of the present disclosure comprises scanning an optical beam by rotating a first scanning mirror, scanning the optical beam scanned by the first scanning mirror by rotating a second scanning mirror, irradiating an object with an optical beam scanned two-dimensionally by the first scanning mirror and the second scanning mirror, and changing the first position of the first scanning mirror according to the orientation of the first scanning mirror so that the optical beam reflected by the first scanning mirror passes through a reference position between the first scanning mirror and the second scanning mirror, regardless of the orientation of the first scanning mirror.

[0030] The object is illuminated with a light beam that is scanned two-dimensionally by a first scanning mirror and a second scanning mirror. Furthermore, regardless of the orientation of the first scanning mirror, the first position of the first scanning mirror is changed according to the orientation of the first scanning mirror so that the light beam reflected by the first scanning mirror passes through a reference position. Therefore, optically, the first scanning mirror can be considered to be at the reference position, while in reality, the first scanning mirror can be positioned further away from the second scanning mirror and the object. Even if the size of the first and second scanning mirrors is large relative to the distance between the second scanning mirror and the object, and the distance between the first and second scanning mirrors as specified in the object's specifications, mechanical interference between two of the first, second, and object can be prevented. For a wider range of object specifications, it becomes possible to scan with a light beam similar to the light beam output from a light beam scanning device included in the device to which the object is applied (e.g., a laser processing device).

[0031] (12) In the optical beam scanning method described in (11) above, the reference position is closer to the second scanning mirror than to the first scanning mirror.

[0032] Therefore, even if the scanning mirror distance specified in the object's specifications is short, it becomes possible to scan the object with a light beam. This makes it possible to scan objects with a wider range of specifications with a light beam.

[0033] (13) The optical beam scanning method according to (11) or (12) above further comprises adjusting the distance between the second scanning mirror and the object.

[0034] Therefore, the distance between the second scanning mirror and the object can be adjusted according to the object's specifications. This makes it possible to scan the light beam over a wider range of objects.

[0035] (14) The optical beam scanning method according to any of (11) to (13) above further comprises changing the third position of the second scanning mirror. The second scanning mirror includes a plurality of mirrors of different sizes. By changing the third position, the optical beam is scanned by one of the plurality of mirrors.

[0036] If the distance between the second scanning mirror and the object must be reduced according to the object's specifications, the light beam can be scanned with a smaller mirror. This prevents the second scanning mirror from mechanically interfering with the object. This makes it possible to scan the light beam over a wider range of object specifications.

[0037] (15) The optical beam scanning method according to any of (11) to (14) above further comprises adjusting the optical path length of the optical beam incident on the first scanning mirror using an optical path length adjuster located in the optical path of the optical beam incident on the first scanning mirror, such that the optical path length of the optical beam from the incident end of the optical path length adjuster to a reference position remains constant regardless of the first position of the first scanning mirror.

[0038] Therefore, even if the light beam spreads as it enters the light beam scanning device, the beam diameter of the light beam at the reference position can be kept constant. The optical properties of the object can be measured more accurately.

[0039] (16) The optical property measurement method of the present disclosure includes the light beam scanning method according to any one of (11) to (15) above, emitting a light beam from a light source, and detecting a light beam that is two-dimensionally scanned by a first scanning mirror and a second scanning mirror and transmitted through an object.

[0040] Therefore, the optical property measurement method of the present disclosure can measure the optical properties of objects with a wider range of specifications using a light beam similar to the light beam output from the light beam scanning device included in the device to which the object is applied.

[0041] (17) The optical property measurement method according to (16) above further includes causing either the first light beam or the second light beam to be incident on the first scanning mirror as the light beam. The light source includes a first light source capable of emitting a first light beam having a first wavelength and a second light source capable of emitting a second light beam having a second wavelength different from the first wavelength.

[0042] Therefore, a light beam having a wavelength specified by the specification of each object can irradiate each object. The optical property measurement method can measure the optical properties of objects with a wider range of specifications.

[0043] (18) In the optical property measurement method according to (16) or (17) above, detecting the light beam means detecting the wavefront of the light beam transmitted through the object.

[0044] Therefore, it becomes possible to measure the optical properties (for example, aberration, etc.) of objects with a wider range of specifications.

[0045] (19) In the optical property measurement method according to any one of (16) to (18) above, the object is an fθ lens.

[0046] Therefore, it becomes possible to measure the optical properties (for example, aberration, modulation transfer function (MTF), telecentric error, light transmittance, etc.) of fθ lenses with a wider range of specifications.

[0047] [Details of Embodiment] Hereinafter, embodiments of the present disclosure will be described based on the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated.

[0048] (Embodiment 1) Referring to FIGS. 1 and 2, the optical property measurement apparatus 1 and the light beam scanning apparatus 2 of Embodiment 1 will be described. The optical property measurement apparatus 1 can measure the optical properties (for example, aberration, etc.) of the object 30. The object 30 is, for example, an optical component. More specifically, the object 30 is a lens such as an fθ lens, an fsinθ lens, or a condenser lens.

[0049] The optical property measurement apparatus 1 includes a light source 11, an optical fiber 13, a collimator lens 15, a beam splitter 16, a beam expander 18, a photodetector 17, a light beam scanning apparatus 2, and a mirror 33.

[0050] The light source 11 can emit a light beam 12. In this embodiment, the light source 11 is a fiber laser. The light source 11 may be a laser light source such as a solid laser, a semiconductor laser, or a gas laser (for example, a carbon dioxide laser, etc.), a light-emitting diode (LED), or a lamp. When the light source 11 is an LED or a lamp, the optical property measurement apparatus 1 may further include a wavelength selection element that selects light having a wavelength specified by the specifications of the object 30 from the light emitted from the LED or the lamp. The wavelength selection element is, for example, a band-pass filter, a prism, or a grating.

[0051] The optical fiber 13 is, for example, a quartz optical fiber or a plastic optical fiber. The collimator lens 15 collimates the light beam 12 emitted from the optical fiber 13. The beam splitter 16 allows the light beam 12 that has passed through the collimator lens 15 to pass through. The beam splitter 16 reflects a part of the light beam 12 reflected by the mirror 33 toward the photodetector 17.

[0052] The beam expander 18 expands the beam diameter of the light beam 12 that travels from the light source 11 to the light beam scanning device 2. The beam expander 18 includes lenses 18a and 18b. Lens 18a expands the beam diameter of the light beam 12, for example. Lens 18b collimates the light beam 12, for example. The light beam 12 that has passed through the beam expander 18 is incident on the light beam scanning device 2 (specifically, the first scanning mirror 20). The beam expander 18 reduces the beam diameter of the light beam 12 that travels from the light beam scanning device 2 to the beam splitter 16.

[0053] Mirror 33 is, for example, a spherical mirror. When the object 30 is a lens, the center of curvature of the spherical mirror is positioned at the point where the light beam 12 is focused by the object 30. The light beam 12 emitted from the object 30 is reflected by the mirror 33 and travels in the opposite direction. The light beam 12 passes through the object 30, is reflected by the second scanning mirror 25 and the first scanning mirror 20, and is emitted from the light beam scanning device 2. The light beam 12 passes through the beam expander 18 and is incident on the beam splitter 16. A portion of the light beam 12 is reflected by the beam splitter 16 and is incident on the photodetector 17.

[0054] The photodetector 17 can detect the light beam 12 that has been scanned two-dimensionally by the light beam scanning device 2 and has passed through the object 30. The photodetector 17 is, for example, a wavefront sensor that detects the wavefront of the light beam 12 that has passed through the object 30. The wavefront sensor is, for example, a Shack-Hartmann wavefront sensor. The photodetector 17 detects the light beam 12 that has passed through the object 30 twice. The optical properties measuring device 1 is a double-pass optical system.

[0055] The optical beam scanning device 2 comprises a first scanning mirror 20, a first mirror rotation mechanism 21, a first moving mechanism 22, a second scanning mirror 25, a second mirror rotation mechanism 26, a second moving mechanism 31, and a mirror moving mechanism 34. The optical beam scanning device 2 may further include a controller 40.

[0056] The first scanning mirror 20 can scan the light beam 12 emitted from the light source 11. The first scanning mirror 20 is a rotatable mirror, including, for example, a vibrating mirror such as a galvanometer mirror and a polygon mirror. The size of the first scanning mirror 20 is larger than the largest beam diameter among the beam diameters specified in the specifications of the object 30 whose optical properties are expected to be measured.

[0057] The first mirror rotation mechanism 21 includes, for example, a motor connected to the first scanning mirror 20. The motor is, for example, a galvanometer motor, a stepping motor, or a servo motor. The first mirror rotation mechanism 21 can rotate the first scanning mirror 20 to change its orientation. Specifically, the first mirror rotation mechanism 21 is connected to the first scanning mirror 20 and the controller 40. The first mirror rotation mechanism 21 can be controlled by the controller 40 to change the orientation of the first scanning mirror 20. The first scanning mirror 20 oscillates to scan the light beam 12 in a first direction on the incident surface of the object 30.

[0058] The first moving mechanism 22 can move the first scanning mirror 20 to change its first position. The first moving mechanism 22 can move the first scanning mirror 20, for example, along the optical path of the light beam 12 incident on the first scanning mirror 20 or along an arc-shaped trajectory. Specifically, the first moving mechanism 22 is connected to the first scanning mirror 20 and the controller 40. The first mirror rotation mechanism 21 can be controlled by the controller 40 to change the first position of the first scanning mirror 20. The first moving mechanism 22 is, for example, a linear stage supporting the first mirror rotation mechanism 21.

[0059] The second scanning mirror 25 can scan the light beam 12 scanned by the first scanning mirror 20. The second scanning mirror 25 is a rotatable mirror, including, for example, a vibrating mirror such as a galvanometer mirror and a polygon mirror.

[0060] The second mirror rotation mechanism 26 includes, for example, a motor connected to the second scanning mirror 25. The motor is, for example, a galvanometer motor, a stepping motor, or a servo motor. The second mirror rotation mechanism 26 can rotate the second scanning mirror 25 to change its orientation. Specifically, the second mirror rotation mechanism 26 is connected to the second scanning mirror 25 and the controller 40. The second mirror rotation mechanism 26 can be controlled by the controller 40 to change the orientation of the second scanning mirror 25. The second scanning mirror 25 oscillates to scan the light beam 12 in a second direction perpendicular to the first direction on the incident surface of the object 30.

[0061] The controller 40 is a microcomputer that includes, for example, a processor and a memory device such as RAM (Random Access Memory) and ROM (Read Only Memory). A CPU (Central Processing Unit) may be used as the processor. RAM functions as working memory for temporarily storing data processed by the processor. The memory device stores, for example, a program executed by the processor. In this embodiment, the controller 40 controls the optical beam scanning device 2 and the optical property measurement device 1 by having the processor execute the program stored in the memory device. Instead of a microcomputer, an FPGA (Field-Programmable Gate Array) may be used as the controller 40. Various processes in the controller 40 are not limited to being executed by software, but may also be implemented by dedicated hardware (electronic circuits).

[0062] The controller 40 can control the first mirror rotation mechanism 21, the first movement mechanism 22, the second mirror rotation mechanism 26, the second movement mechanism 31, and the mirror movement mechanism 34.

[0063] The controller 40 controls the orientation of the first scanning mirror 20 by controlling the first mirror rotation mechanism 21, causing the first scanning mirror 20 to oscillate. The controller 40 controls the orientation of the second scanning mirror 25 by controlling the second mirror rotation mechanism 26, causing the second scanning mirror 25 to oscillate. The object 30 is illuminated by a light beam 12 that is scanned two-dimensionally by the first scanning mirror 20 and the second scanning mirror 25.

[0064] The controller 40 can control the first moving mechanism 22 according to the orientation of the first scanning mirror 20 so that the light beam 12 reflected by the first scanning mirror 20 passes through a reference position 24 located between the first scanning mirror 20 and the second scanning mirror 25, regardless of the orientation of the first scanning mirror 20. The distance between the reference position 24 and the second scanning mirror 25 is, for example, the distance between the first scanning mirror 20 and the second scanning mirror 25 (scanning mirror distance) as defined in the specifications of the object 30. The reference position 24 may be closer to the second scanning mirror 25 than to the first scanning mirror 20.

[0065] The second moving mechanism 31 can move the object 30 to adjust its second position. Specifically, the second moving mechanism 31 is connected to the object 30 and the controller 40. The second moving mechanism 31 can be controlled by the controller 40 to change the second position of the object 30. By adjusting the second position of the object 30 using the second moving mechanism 31, the distance between the second scanning mirror 25 and the object 30 is adjusted to the distance specified in the specifications of the object 30. The second moving mechanism 31 is, for example, a linear stage that supports the object 30.

[0066] The mirror moving mechanism 34 can move the mirror 33 so that the mirror 33 reflects the light beam 12 scanned two-dimensionally by the light beam scanning device 2. Specifically, the mirror moving mechanism 34 is connected to the mirror 33 and the controller 40. The mirror moving mechanism 34 can move the mirror 33 under the control of the controller 40. The mirror moving mechanism 34 is, for example, a three-dimensional moving stage that supports the mirror 33.

[0067] An example of the optical beam scanning method and the optical properties measurement method of the object 30 according to this embodiment will be described with reference to Figures 1 and 2.

[0068] The controller 40 controls the second movement mechanism 31 to adjust the second position of the object 30 so that the distance between the second scanning mirror 25 and the object 30 becomes the distance specified in the specifications of the object 30.

[0069] The light source 11 emits a light beam 12. The light beam 12 passes through the optical fiber 13 and enters the collimator lens 15. The light beam 12 is collimated by the collimator lens 15. The light beam 12 passes through the beam splitter 16 and the beam expander 18 and enters the light beam scanning device 2. The beam expander 18 expands the beam diameter of the light beam 12.

[0070] The controller 40 controls the first mirror rotation mechanism 21 to rotate the first scanning mirror 20. The first scanning mirror 20 oscillates and scans the light beam 12. The light beam 12 scanned by the first scanning mirror 20 is incident on the second scanning mirror 25. The controller 40 controls the second mirror rotation mechanism 26 to rotate the second scanning mirror 25. The second scanning mirror 25 oscillates and scans the light beam 12 scanned by the first scanning mirror 20. In this way, the light beam 12 emitted from the light source 11 is scanned two-dimensionally by the first scanning mirror 20 and the second scanning mirror 25. The object 30 is illuminated by the light beam 12 scanned two-dimensionally by the first scanning mirror 20 and the second scanning mirror 25.

[0071] When scanning the light beam 12, the controller 40 changes the first position of the first scanning mirror 20 according to the orientation of the first scanning mirror 20, so that the light beam 12 reflected by the first scanning mirror 20 passes through a reference position 24 located between the first scanning mirror 20 and the second scanning mirror 25, regardless of the orientation of the first scanning mirror 20. For example, the first position of the first scanning mirror 20 is changed along the optical path of the light beam 12 incident on the first scanning mirror 20, or along an arc-shaped trajectory, so that the light beam 12 passes through the reference position 24 regardless of the orientation of the first scanning mirror 20. Therefore, optically, the first scanning mirror 20 can be considered to be positioned at the reference position 24. The distance between the reference position 24 and the second scanning mirror 25 is, for example, the distance between the first scanning mirror 20 and the second scanning mirror 25 (scanning mirror distance) as specified in the specifications of the object 30. The reference position 24 may be closer to the second scanning mirror 25 than to the first scanning mirror 20.

[0072] The controller 40 controls the mirror movement mechanism 34 to move the mirror 33 so that the two-dimensionally scanned light beam 12 can be reflected by the mirror 33. The light beam 12 that has passed through the object 30 is reflected by the mirror 33 and travels in the opposite direction. The light beam 12 passes through the object 30, is reflected by the second scanning mirror 25 and the first scanning mirror 20, and is emitted from the light beam scanning device 2. The light beam 12 passes through the beam expander 18 and is incident on the beam splitter 16. A portion of the light beam 12 is reflected by the beam splitter 16 and is incident on the photodetector 17.

[0073] The photodetector 17 detects the light beam 12 that has been scanned two-dimensionally by the first scanning mirror 20 and the second scanning mirror 25 and has passed through the object 30. The photodetector 17 is a wavefront sensor, such as a Shack-Hartmann wavefront sensor. The photodetector 17 detects the wavefront of the light beam 12 that has passed through the object 30 after passing through the light beam scanning device 2. The wavefront of the light beam 12 reflects the optical properties (e.g., aberrations) of the object 30. Therefore, the optical properties of the object 30 can be calculated from the wavefront of the light beam 12. In this way, the optical properties of the object 30 can be measured.

[0074] The operation of this embodiment will be explained in comparison with the comparative example. In the comparative example, the position of the second scanning mirror 25 is set so that the distance between the second scanning mirror 25 and the object 30 is the distance specified in the specifications of the object 30. The position of the first scanning mirror 20 is set so that the distance between the first scanning mirror 20 and the second scanning mirror 25 is the distance between the first scanning mirror 20 and the second scanning mirror 25 (scanning mirror distance) specified in the specifications of the object 30.

[0075] In the comparative example, depending on the specifications of the object 30, the size of the first scanning mirror 20, and the size of the second scanning mirror 25, two of the first scanning mirror 20, the second scanning mirror 25, and the object 30 sometimes mechanically interfered with each other. Therefore, in the comparative example, it was not possible to measure the optical properties of an object 30 having certain specifications. Furthermore, it was sometimes not possible to measure the optical properties of the object 30 using a light beam 12 having a beam diameter, incident position on the object 30, and incident angle on the object 30 similar to the light beam output from a light beam scanning device included in the device to which the object 30 is applied (for example, a laser processing device).

[0076] In contrast, in this embodiment, the object 30 is illuminated by a light beam 12 that is scanned two-dimensionally by a first scanning mirror 20 and a second scanning mirror 25. Furthermore, regardless of the orientation of the first scanning mirror 20, the first position of the first scanning mirror 20 is changed according to the orientation of the first scanning mirror 20 so that the light beam 12 reflected by the first scanning mirror 20 passes through the reference position 24. The distance between the reference position 24 and the second scanning mirror 25 is the scanning mirror distance specified in the specifications of the object 30. Therefore, optically, the first scanning mirror 20 can be considered to be located at the reference position 24, but in reality, the first scanning mirror 20 can be positioned further away from the second scanning mirror 25 and the object 30 (e.g., the fθ lens).

[0077] Even if the size of the first scanning mirror 20 and the size of the second scanning mirror 25 are large relative to the distance between the second scanning mirror 25 and the object 30 and the distance between the first scanning mirror 20 and the second scanning mirror 25 (scanning mirror distance) as specified in the specifications of the object 30, it is possible to prevent two of the first scanning mirror 20, the second scanning mirror 25, and the object 30 from mechanically interfering with each other. According to this embodiment, it becomes possible to scan an object 30 with a wider range of specifications using a light beam 12 having a beam diameter, incident position on the object 30, and incident angle on the object 30 similar to the light beam output from a light beam scanning device included in the device to which the object 30 is applied (e.g., a laser processing device). The optical properties of the object 30 can be measured using a light beam 12 having a beam diameter, incident position on the object 30, and incident angle on the object 30 similar to the light beam output from a light beam scanning device included in the device to which the object 30 is applied (e.g., a laser processing device).

[0078] (Embodiment 2) The optical characteristic measuring device 1 and the optical beam scanning device 2 of Embodiment 2 will be described with reference to Figures 3 and 4. The optical characteristic measuring device 1 and the optical beam scanning device 2 of this embodiment are configured similarly to the optical characteristic measuring device 1 and the optical beam scanning device 2 of Embodiment 1, but differ from the optical characteristic measuring device 1 and the optical beam scanning device 2 of Embodiment 1 mainly in the following points.

[0079] In this embodiment, the second scanning mirror 25 includes a plurality of mirrors of different sizes. The plurality of mirrors are, for example, a first mirror 25a, a second mirror 25b, and a third mirror 25c. The first mirror 25a is larger in size than the second mirror 25b. The second mirror 25b is larger in size than the third mirror 25c. The first mirror 25a is used to scan an optical beam 12 having a first beam diameter. The second mirror 25b is used to scan an optical beam 12 having a second beam diameter smaller than the first beam diameter. The third mirror 25c is used to scan an optical beam 12 having a third beam diameter smaller than the second beam diameter. The first mirror 25a, the second mirror 25b, and the third mirror 25c are connected to each other. The first mirror 25a is connected to the second mirror rotation mechanism 26.

[0080] The optical beam scanning device 2 of this embodiment further comprises a third moving mechanism 27. The third moving mechanism 27 can change the third position of the second scanning mirror 25. Specifically, the third moving mechanism 27 is connected to the second scanning mirror 25 and a controller 40. The third moving mechanism 27 can be controlled by the controller 40 to change the third position of the second scanning mirror 25. The controller 40 can control the third moving mechanism 27 so that the optical beam 12 is scanned by one of a plurality of mirrors (for example, a first mirror 25a, a second mirror 25b, and a third mirror 25c). A mirror for scanning the optical beam 12 is selected from the plurality of mirrors. The third moving mechanism 27 is, for example, a linear stage supporting the second mirror rotation mechanism 26.

[0081] The optical beam scanning method and optical property measurement method of this embodiment will be described with reference to Figures 3 and 4. The optical beam scanning method and optical property measurement method of this embodiment have the same steps as the optical beam scanning method and optical property measurement method of Embodiment 1, but differ from the optical beam scanning method and optical property measurement method of Embodiment 1 mainly in the following points.

[0082] In the optical beam scanning method and optical property measurement method of this embodiment, the third position of the second scanning mirror 25, which includes a plurality of mirrors of different sizes (for example, a first mirror 25a, a second mirror 25b, and a third mirror 25c), is changed. By changing the third position, the optical beam 12 is scanned by one of the plurality of mirrors.

[0083] If the distance between the second scanning mirror 25 and the object 30 must be reduced according to the specifications of the object 30, the light beam 12 is scanned with a smaller mirror (e.g., a third mirror 25c). This prevents the second scanning mirror 25 from mechanically interfering with the object 30. Also, if the beam diameter of the light beam 12 is small as specified in the specifications of the object 30, the light beam 12 is scanned with a smaller mirror (e.g., a third mirror 25c).

[0084] (Embodiment 3) The optical properties measuring device 1 and the optical beam scanning device 2 of Embodiment 3 will be described with reference to Figures 5 and 6. The optical properties measuring device 1 and the optical beam scanning device 2 of this embodiment are configured similarly to the optical properties measuring device 1 and the optical beam scanning device 2 of Embodiment 2, but differ from the optical properties measuring device 1 and the optical beam scanning device 2 of Embodiment 2 mainly in the following points.

[0085] The optical beam scanning device 2 of this embodiment further includes an optical path length adjuster 36. The optical path length adjuster 36 is positioned on the optical path of the optical beam 12 incident on the first scanning mirror 20. The optical path length adjuster 36 can adjust the optical path length of the optical beam 12 incident on the first scanning mirror 20 so that the optical path length of the optical beam 12 from the incident end of the optical path length adjuster 36 to the reference position 24 remains constant, regardless of the first position of the first scanning mirror 20. The optical path length adjuster 36 includes, for example, mirrors 36a and 36b, a right-angle prism 36c, and a fourth moving mechanism 37.

[0086] The right-angle prism 36c has two reflective surfaces. The light beam 12 emitted from the light source 11 passes through the collimator lens 15 and the beam splitter 16 and enters the mirror 36a. Mirror 36a is the entry end of the optical path length adjuster 36. The light beam 12 is reflected by mirror 36a and enters the right-angle prism 36c. The light beam 12 is reflected by the two reflective surfaces of the right-angle prism 36c. The light beam 12 is reflected by mirror 36b and exits the optical path length adjuster 36.

[0087] The fourth moving mechanism 37 can move the right-angle prism 36c to change the distance between the mirrors 36a, 36b and the right-angle prism 36c. Specifically, the fourth moving mechanism 37 is connected to the right-angle prism 36c and the controller 40. The fourth moving mechanism 37 can be controlled by the controller 40 to change the position of the right-angle prism 36c. The distance between the mirrors 36a, 36b, the right-angle prism 36c and the object 30 is adjusted to adjust the optical path length of the light beam 12 incident on the first scanning mirror 20. The fourth moving mechanism 37 is, for example, a linear stage supporting the right-angle prism 36c.

[0088] The controller 40 can control the optical path length adjuster 36 (more specifically, the fourth moving mechanism 37). Specifically, the controller 40 controls the optical path length adjuster 36 according to the first position of the first scanning mirror 20. Regardless of the first position of the first scanning mirror 20, the optical path length adjuster 36 adjusts the optical path length of the light beam 12 incident on the first scanning mirror 20 so that the optical path length of the light beam 12 from the incident end of the optical path length adjuster 36 to the reference position 24 remains constant.

[0089] The optical beam scanning method and optical property measurement method of this embodiment will be described with reference to Figures 5 and 6. The optical beam scanning method and optical property measurement method of this embodiment have the same steps as the optical beam scanning method and optical property measurement method of Embodiment 2, but differ from the optical beam scanning method and optical property measurement method of Embodiment 2 mainly in the following points.

[0090] In the optical beam scanning method and optical characteristic measurement method of this embodiment, an optical path length adjuster 36, which is positioned on the optical path of the optical beam 12 incident on the first scanning mirror 20, is used to adjust the optical path length of the optical beam 12 incident on the first scanning mirror 20 so that the optical path length of the optical beam 12 from the incident end of the optical path length adjuster 36 to the reference position 24 remains constant regardless of the first position of the first scanning mirror 20.

[0091] A light beam 12 having a divergence angle specified in the specifications of the object 30 may be incident on the object 30. A light beam 12 having a divergence angle is generated by shifting at least one position of lens 18a or lens 18b along the optical path of the light beam 12. If the light beam 12 incident on the first scanning mirror 20 has a divergence angle and there is no optical path length adjuster 36, when the first position of the first scanning mirror 20 changes, the optical path length of the light beam 12 from the collimator lens 15 to the reference position 24 changes, and the beam diameter of the light beam 12 at the reference position 24 changes. Therefore, it is not possible to measure the optical properties of the object 30 using a light beam 12 having a beam diameter specified in the specifications of the object 30.

[0092] In contrast, in this embodiment, the optical path length adjuster 36 adjusts the optical path length of the light beam 12 incident on the first scanning mirror 20 so that the optical path length of the light beam 12 from the incident end of the optical path length adjuster 36 to the reference position 24 remains constant, regardless of the first position of the first scanning mirror 20. Therefore, even if the light beam 12 incident on the first scanning mirror 20 has a divergence angle, the beam diameter of the light beam 12 at the reference position 24 can be kept constant, regardless of the first position of the first scanning mirror 20.

[0093] Therefore, the optical properties of the object 30 can be measured using a light beam 12 having a beam diameter specified in the specifications of the object 30. The optical properties of the object 30 can be measured more accurately. In addition, the optical properties of the object 30 can be measured with a light beam 12 similar to the light beam output from a light beam scanning device included in the device to which the object 30 is applied (for example, a laser processing device). According to this embodiment, it becomes possible to scan an object 30 with a wider range of specifications using a light beam 12 similar to the light beam output from a light beam scanning device included in the device to which the object 30 is applied (for example, a laser processing device). The optical properties of an object 30 with a wider range of specifications can be measured with a light beam 12 similar to the light beam output from a light beam scanning device included in the device to which the object 30 is applied.

[0094] The optical path length adjuster 36 may also include two movable mirrors instead of the right-angle prism 36c.

[0095] (Embodiment 4) The optical properties measuring device 1 of Embodiment 4 will be described with reference to Figures 7 and 8. The optical properties measuring device 1 of this embodiment is configured similarly to the optical properties measuring device 1 of Embodiment 3, but differs from the optical properties measuring device 1 of Embodiment 3 mainly in the following points.

[0096] In the optical properties measuring device 1 of this embodiment, the light source 11 includes a plurality of light sources. Each of the plurality of light sources can emit light beams having different wavelengths from each other. The plurality of light sources are, for example, a first light source 11a, a second light source 11b, and a third light source 11c. The first light source 11a can emit a first light beam 12a having a first wavelength. The second light source 11b can emit a second light beam 12b having a second wavelength different from the first wavelength. The third light source 11c can emit a third light beam 12c having a third wavelength different from the first and second wavelengths.

[0097] The optical fiber 13 includes multiple optical fibers. These multiple optical fibers are, for example, a first optical fiber 13a, a second optical fiber 13b, and a third optical fiber 13c. The first optical fiber 13a is connected to the first light source 11a. The first light beam 12a travels through the first optical fiber 13a. The second optical fiber 13b is connected to the second light source 11b. The second light beam 12b travels through the second optical fiber 13b. The third optical fiber 13c is connected to the third light source 11c. The third light beam 12c travels through the third optical fiber 13c.

[0098] The optical characteristic measuring device 1 of this embodiment further includes a beam selector 38 (see Figure 8). The beam selector 38 causes one of a plurality of optical beams (for example, a first optical beam 12a, a second optical beam 12b, and a third optical beam 12c) to be incident on the optical beam scanning device 2 (more specifically, the first scanning mirror 20) as the optical beam 12. Specifically, the beam selector 38 is connected to a first optical fiber 13a, a second optical fiber 13b, a third optical fiber 13c, and a controller 40. The beam selector 38 is controlled by the controller 40 to optically couple one of the first optical fiber 13a, the second optical fiber 13b, or the third optical fiber 13c to the first scanning mirror 20 through a collimator lens 15, a beam splitter 16, and a beam expander 18. In this way, one of the first optical beam 12a, the second optical beam 12b, or the third optical beam 12c is incident on the optical beam scanning device 2. The beam selector 38 is, for example, a moving stage that supports the first optical fiber 13a, the second optical fiber 13b, and the third optical fiber 13c.

[0099] The optical properties measurement method of this embodiment will be described with reference to Figures 7 and 8. The optical properties measurement method of this embodiment has the same steps as the optical properties measurement method of Embodiment 3, but differs from the optical properties measurement method of Embodiment 3 mainly in the following points.

[0100] In the optical property measurement method of this embodiment, one of a plurality of light beams (for example, a first light beam 12a, a second light beam 12b, or a third light beam 12c) is incident on the first scanning mirror 20 as the light beam 12. Specifically, the controller 40 controls the beam selector 38 to optically couple one of the first optical fiber 13a, the second optical fiber 13b, or the third optical fiber 13c to the first scanning mirror 20 through the collimator lens 15, beam splitter 16, and beam expander 18. In this way, the beam selector 38 causes one of the first light beam 12a, the second light beam 12b, or the third light beam 12c to be incident on the light beam scanning device 2. The first light beam 12a, the second light beam 12b, or the third light beam 12c selected by the beam selector 38 is, for example, a wavelength specified in the specifications of the object 30.

[0101] The object 30 is scanned two-dimensionally with either the first light beam 12a, the second light beam 12b, or the third light beam 12c. The optical properties of the object 30 can be measured with either the first light beam 12a, the second light beam 12b, or the third light beam 12c. The optical properties of the object 30 can be measured for a wider range of specifications. Note that the number of light sources and optical fibers is not limited to three; it may be two, four or more.

[0102] (Embodiment 5) The optical properties measuring device 1 of Embodiment 5 will be described with reference to Figures 8 and 9. The optical properties measuring device 1 of this embodiment is configured in the same way as the optical properties measuring device 1 of Embodiment 4 and has the same effects as the optical properties measuring device 1 of Embodiment 4, but differs from the optical properties measuring device 1 of Embodiment 4 mainly in the following points.

[0103] The optical characteristic measuring device 1 of this embodiment includes a beam selector 38 which comprises an optical combiner 43 and a plurality of optical shutters. The plurality of optical shutters are, for example, a first optical shutter 38a, a second optical shutter 38b, and a third optical shutter 38c.

[0104] The optical combiner 43 combines multiple light beams (for example, a first light beam 12a, a second light beam 12b, and a third light beam 12c) and optically couples the multiple light beams to the first scanning mirror 20 through the collimator lens 15, beam splitter 16, and beam expander 18. The optical combiner 43 includes, for example, mirrors 44a, 44b and optical multiplexers 45a, 45b. The optical multiplexers 45a, 45b are, for example, optical filters such as dichroic filters. The first light beam 12a emitted from the first light source 11a passes through the optical multiplexers 45a, 45b and is incident on the collimator lens 15. The second light beam 12b emitted from the second light source 11b is reflected by the mirror 44a and optical multiplexer 45a and is incident on the collimator lens 15. The third light beam 12c emitted from the third light source 11c is reflected by the mirror 44b and the optical multiplexer 45b and incident on the collimator lens 15.

[0105] The first optical shutter 38a is positioned in the optical path of the first optical beam 12a. For example, the first optical shutter 38a is positioned between the first light source 11a and the optical multiplexer 45a. The first optical shutter 38a transmits or blocks the first optical beam 12a. The second optical shutter 38b is positioned in the optical path of the second optical beam 12b. For example, the second optical shutter 38b is positioned between the second light source 11b and the mirror 44a. The second optical shutter 38b transmits or blocks the second optical beam 12b. The third optical shutter 38c is positioned in the optical path of the third optical beam 12c. For example, the third optical shutter 38c is positioned between the third light source 11c and the mirror 44b. The third optical shutter 38c transmits or blocks the third optical beam 12c. The first light shutter 38a, the second light shutter 38b, and the third light shutter 38c are, for example, electro-optic shutters such as liquid crystal light shutters, or mechanical shutters including a movable light-shielding plate.

[0106] The beam selector 38 is connected to the controller 40. The controller 40 controls the beam selector 38 to open one of the first light shutter 38a, second light shutter 38b, or third light shutter 38c, and to close the remaining one of the first light shutter 38a, second light shutter 38b, or third light shutter 38c. In this way, one of the first light beam 12a, second light beam 12b, or third light beam 12c is incident on the first scanning mirror 20 through the collimator lens 15, beam splitter 16, and beam expander 18.

[0107] The optical properties measurement method of this embodiment will be described with reference to Figures 8 and 9. The optical properties measurement method of this embodiment comprises the same steps as the optical properties measurement method of Embodiment 4 and achieves the same effects as the optical properties measurement method of Embodiment 4, but differs from the optical properties measurement method of Embodiment 4 mainly in the following points.

[0108] In the optical property measurement method of this embodiment, one of the first light beam 12a, the second light beam 12b, or the third light beam 12c is incident on the first scanning mirror 20 as the light beam 12. Specifically, the controller 40 controls the beam selector 38 to open one of the first light shutter 38a, the second light shutter 38b, or the third light shutter 38c, and to close the remaining one of the first light shutter 38a, the second light shutter 38b, or the third light shutter 38c. In this way, the beam selector 38 optically couples one of the first light beam 12a, the second light beam 12b, or the third light beam 12c to the light beam scanning device 2. The one of the first light beam 12a, the second light beam 12b, or the third light beam 12c selected by the beam selector 38 is, for example, a wavelength specified in the specifications of the object 30.

[0109] The object 30 is scanned two-dimensionally with either the first light beam 12a, the second light beam 12b, or the third light beam 12c. The optical properties of the object 30 can be measured with either the first light beam 12a, the second light beam 12b, or the third light beam 12c. The optical properties of an object 30 with a wider range of specifications can be measured. Note that the number of light sources and light shutters are not limited to three, but may be two, four or more, respectively.

[0110] (Embodiment 6) The optical properties measuring device 1 of Embodiment 6 will be described with reference to Figures 10 and 11. The optical properties measuring device 1 of this embodiment is configured in the same way as the optical properties measuring device 1 of Embodiment 4 and has the same effects as the optical properties measuring device 1 of Embodiment 4, but differs from the optical properties measuring device 1 of Embodiment 4 mainly in the following points.

[0111] The optical characteristic measuring device 1 of this embodiment does not have a beam splitter 16, and instead of a mirror 33, it has a detection optical system 46. The detection optical system 46 includes, for example, a lens 47, a relay lens 48, and a photodetector 17. The optical characteristic measuring device 1 of this embodiment has a detection optical system moving mechanism 35 instead of a mirror moving mechanism 34 (see Figure 8).

[0112] The detection optical system 46 is an optical system for detecting the light beam 12 that has passed through the object 30. The lens 47 collimates the light beam 12 that has passed through the object 30. For example, if the object 30 is a lens, the lens 47 is positioned so that its focal point coincides with the point of focus of the light beam 12 caused by the object 30. The light beam 12 collimated by the lens 47 passes through the relay lens 48 and enters the photodetector 17.

[0113] The detection optical system moving mechanism 35 moves the detection optical system 46. Specifically, the detection optical system moving mechanism 35 can move the lens 47, the relay lens 48, and the photodetector 17 so that the light beam 12, which has been scanned two-dimensionally by the light beam scanning device 2 and passed through the object 30, enters the photodetector 17. For example, the detection optical system moving mechanism 35 is connected to the lens 47, the relay lens 48, and the photodetector 17. The detection optical system moving mechanism 35 can move the lens 47, the relay lens 48, and the photodetector 17 under the control of the controller 40. The detection optical system moving mechanism 35 is, for example, a three-dimensional moving stage that supports the lens 47, the relay lens 48, and the photodetector 17.

[0114] The photodetector 17 detects the light beam 12 that has been scanned two-dimensionally by the light beam scanning device 2 and has passed through the object 30. The photodetector 17 detects the light beam 12 that has passed through the object 30 once. The optical properties measuring device 1 is a single-pass optical system.

[0115] The optical properties measurement method of this embodiment will be described with reference to Figures 10 and 11. The optical properties measurement method of this embodiment comprises the same steps as the optical properties measurement method of Embodiment 4 and has the same effects as the optical properties measurement method of Embodiment 4. Specifically, in the optical properties measurement method of this embodiment, the controller 40 controls the detection optical system movement mechanism 35 to move the lens 47, relay lens 48, and photodetector 17 so that the light beam 12, which has been scanned two-dimensionally by the light beam scanning device 2 and passed through the object 30, is incident on the photodetector 17. The light beam 12 that has passed through the object 30 once is detected by the photodetector 17 to measure the optical properties of the object 30.

[0116] Embodiments 1-6 disclosed herein should be considered in all respects to be illustrative and not restrictive. To the extent that they do not contradict each other, at least two of Embodiments 1-6 disclosed herein may be combined. The scope of this disclosure is indicated by the claims rather than the embodiments described above, and all modifications within the scope of the claims are intended to be included in the meaning of equivalences and within the scope of the claims.

[0117] 1 Optical properties measuring device, 2 Light beam scanning device, 11 Light source, 11a First light source, 11b Second light source, 11c Third light source, 12 Light beam, 12a First light beam, 12b Second light beam, 12c Third light beam, 13 Optical fiber, 13a First optical fiber, 13b Second optical fiber, 13c Third optical fiber, 15 Collimator lens, 16 Beam splitter, 17 Photodetector, 18 Beam expander, 18a, 18b Lens, 20 First scanning mirror, 21 First mirror rotation mechanism, 22 First movement mechanism, 24 Reference position, 25 Second scanning mirror, 25a First mirror, 25b Second mirror, 25c Third mirror, 26 Second mirror rotation mechanism, 27 Third movement mechanism, 30 Object, 31 Second movement mechanism, 33 Mirror, 34 Mirror movement mechanism, 35 Detection optical system movement mechanism, 36 Optical path length adjuster, 36a, 36b Mirror, 36c Right-angle prism, 37 Fourth moving mechanism, 38 Beam selector, 38a First light shutter, 38b Second light shutter, 38c Third light shutter, 40 Controller, 43 Optical combiner, 44a, 44b Mirror, 45a, 45b Optical multiplexer, 46 Detection optical system, 47 Lens, 48 ​​Relay lens.

Claims

1. A light beam scanning device comprising: a first scanning mirror capable of scanning a light beam; a second scanning mirror capable of scanning the light beam scanned by the first scanning mirror; a first mirror rotation mechanism capable of changing the orientation of the first scanning mirror; and a first movement mechanism capable of changing the first position of the first scanning mirror, wherein an object is illuminated by the light beam scanned two-dimensionally by the first scanning mirror and the second scanning mirror, and the first position is changed according to the orientation of the first scanning mirror so that the light beam reflected by the first scanning mirror passes through a reference position located between the first scanning mirror and the second scanning mirror, regardless of the orientation of the first scanning mirror.

2. The optical beam scanning apparatus according to claim 1, further comprising a controller, the controller controlling the first moving mechanism according to the orientation of the first scanning mirror so that the optical beam reflected by the first scanning mirror passes through the reference position, regardless of the orientation of the first scanning mirror.

3. The optical beam scanning apparatus according to claim 1 or 2, wherein the reference position is closer to the second scanning mirror than to the first scanning mirror.

4. The optical beam scanning apparatus according to any one of claims 1 to 3, further comprising a second moving mechanism capable of adjusting the second position of the object, wherein the distance between the second scanning mirror and the object is adjusted by adjusting the second position.

5. The optical beam scanning apparatus according to any one of claims 1 to 4, further comprising a third moving mechanism that can change the third position of the second scanning mirror, wherein the second scanning mirror includes a plurality of mirrors of different sizes, and the third position is changed so that the optical beam is scanned by one of the plurality of mirrors.

6. The optical beam scanning apparatus according to any one of claims 1 to 3, further comprising an optical path length adjuster positioned in the optical path of the light beam incident on the first scanning mirror, wherein the optical path length adjuster can adjust the optical path length of the light beam incident on the first scanning mirror so that the optical path length of the light beam from the incident end of the optical path length adjuster to the reference position remains constant, regardless of the first position of the first scanning mirror.

7. An optical properties measuring device comprising: the light beam scanning device according to any one of claims 1 to 6; a light source capable of emitting the light beam; and a photodetector capable of detecting the light beam that has been scanned two-dimensionally by the first scanning mirror and the second scanning mirror and has passed through the object.

8. The optical property measuring apparatus according to claim 7, further comprising a beam selector, wherein the light source includes a first light source capable of emitting a first light beam having a first wavelength and a second light source capable of emitting a second light beam having a second wavelength different from the first wavelength, and the beam selector causes either the first light beam or the second light beam to be incident on the first scanning mirror as the light beam.

9. The optical property measuring device according to claim 7 or claim 8, wherein the photodetector is a wavefront sensor that detects the wavefront of the light beam that has passed through the object.

10. The optical property measuring apparatus according to any one of claims 7 to 9, wherein the object is an fθ lens.

11. A method for scanning a light beam, comprising: scanning a light beam by rotating a first scanning mirror; scanning the light beam scanned by the first scanning mirror by rotating a second scanning mirror; irradiating an object with the light beam scanned two-dimensionally by the first scanning mirror and the second scanning mirror; and changing the first position of the first scanning mirror according to the orientation of the first scanning mirror so that, regardless of the orientation of the first scanning mirror, the light beam reflected by the first scanning mirror passes through a reference position located between the first scanning mirror and the second scanning mirror.

12. The optical beam scanning method according to claim 11, wherein the reference position is closer to the second scanning mirror than to the first scanning mirror.

13. The optical beam scanning method according to claim 11 or 12, further comprising adjusting the distance between the second scanning mirror and the object.

14. The optical beam scanning method according to any one of claims 11 to 13, further comprising changing the third position of the second scanning mirror, wherein the second scanning mirror comprises a plurality of mirrors of different sizes, and by changing the third position, the optical beam is scanned by one of the plurality of mirrors.

15. The optical beam scanning method according to any one of claims 11 to 14, further comprising adjusting the optical path length of the light beam incident on the first scanning mirror using an optical path length adjuster positioned on the optical path of the light beam incident on the first scanning mirror, such that the optical path length of the light beam from the incident end of the optical path length adjuster to the reference position remains constant regardless of the first position of the first scanning mirror.

16. An optical property measurement method comprising the optical beam scanning method according to any one of claims 11 to 15, emitting the optical beam from a light source, and detecting the optical beam that has been scanned two-dimensionally by the first scanning mirror and the second scanning mirror and has passed through the object.

17. The optical property measurement method according to claim 16, further comprising injecting either a first light beam or a second light beam onto the first scanning mirror as the light beam, wherein the light source includes a first light source capable of emitting the first light beam having a first wavelength and a second light source capable of emitting the second light beam having a second wavelength different from the first wavelength.

18. The optical property measurement method according to claim 16 or 17, wherein detecting the light beam means detecting the wavefront of the light beam that has passed through the object.

19. The optical property measurement method according to any one of claims 16 to 18, wherein the object is an fθ lens.

Images