Optical devices and three-dimensional modeling devices

Abstract

In the shading unit (24), the introduction reflection surface (41) is located near the focus position of the first-order diffraction beam on the optical axis (J36) of the first-order diffraction beam and near the opening (240) of the 0th-order diffraction beam. The introduction reflection surface (41) reflects the first-order diffraction beam in a direction deviating from the incident direction of the first-order diffraction beam and away from the optical axis (J35) of the 0th-order diffraction beam. The light guide (42) has an introduction port (44) for light from the introduction reflection surface (41) to be incident, and guides the light introduced from the introduction port (44). The light guide (42) is surrounded by a shading component. The light absorbing portion (43) absorbs the light diffused and guided by the light guide (42). Thus, it is possible to suppress light from leaking out of the shading unit (24) and to suppress the temperature rise of the shading unit (24).

Description

Technical Field

[0001] The present invention relates to an optical device for irradiating a modulated light beam onto an irradiation surface on an object, and a three-dimensional modeling device having the optical device.

[0002] [Reference to related applications]

[0003] This application claims priority to Japanese patent application JP2020-198677 filed on November 30, 2020, and the entire disclosure of that application is incorporated into this application. Background Art

[0004] In recent years, SLM (Selective Laser Melting)-style three-dimensional modeling devices have been used, which perform three-dimensional modeling by irradiating a modeling material such as metal powder with a modulated laser beam, melting the modeling material, and thus performing three-dimensional modeling. For example, these three-dimensional modeling devices use an optical device that modulates the laser beam using a diffraction-type light modulator and then irradiates the modeling material. In this optical device, the 0th-order diffracted beam from the light modulator is directed toward the modeling material, while higher-order diffracted beams, such as the 1st-order diffracted beam, that do not reach the modeling material are shielded by a light shielding portion within the optical device. To prevent the light shielding portion and the optical device from becoming larger, the light shielding portion is typically located near the focal point of the 1st-order diffracted beam and the like.

[0005] This optical device is also used in a pattern drawing device that draws a pattern by irradiating a laser onto a substrate. In the pattern drawing device of International Publication No. 2018 / 150996 (Document 1), an absorber is provided in the head to absorb the diffracted light beam that is not used in drawing the pattern. Figure 3 As shown, when the absorber TR is arranged separately from other optical elements such as a reflector, the optical device becomes larger.

[0006] However, in the above-mentioned three-dimensional modeling device, it is required to improve productivity, and research is being conducted to increase the energy density of the laser light irradiated on the modeling material (i.e., the light intensity per unit area). When the energy density of the laser light increases, the heat converted from the laser light becomes larger in the area that blocks or absorbs the diffracted light beam, such as the above-mentioned shading portion, and the heat cannot be discharged in time, causing the temperature of the shading portion to rise locally, and the shading portion may be damaged. In addition, as the temperature of the shading portion rises, the temperature of the surrounding components also rises, and the laser irradiation accuracy may also decrease. In addition, there is a possibility that the scattered light that is not completely absorbed by the shading portion and leaks to the surrounding area will cause the temperature of the surrounding components to rise, and the laser irradiation accuracy will be reduced. Summary of the Invention

[0007] The present invention relates to an optical device for irradiating modulated light onto an object, and an object thereof is to suppress light leakage from a light shielding unit to the outside and to suppress a temperature increase of the light shielding unit.

[0008] An optical device according to a preferred embodiment of the present invention comprises: an illumination optical system for shaping laser light emitted from a laser light source into a predetermined shape; a light modulator for modulating the laser light shaped by the illumination optical system into a modulated light beam; and a projection optical system for guiding the modulated light beam toward an object. The projection optical system includes a light shielding unit for transmitting a zero-order diffracted light beam from the light modulator and shielding a first-order diffracted light beam. The shading unit comprises: a 0th-order diffraction beam opening, located near the focusing position of the 0th-order diffraction beam on the optical axis of the 0th-order diffraction beam, allowing the 0th-order diffraction beam to pass through; an inlet reflection surface, located near the focusing position of the 1st-order diffraction beam on the optical axis of the 1st-order diffraction beam and located near the 0th-order diffraction beam opening, reflecting the 1st-order diffraction beam in a direction deviating from the incident direction of the 1st-order diffraction beam and away from the optical axis of the 0th-order diffraction beam; a light guide path, having an inlet for incident light from the inlet reflection surface, guiding the light introduced from the inlet, the light guide path being surrounded by a shading component; and a light absorbing portion, absorbing the light diffused and guided through the light guide path.

[0009] According to the present invention, it is possible to suppress leakage of light from the light shielding unit to the outside and to suppress a temperature increase of the light shielding unit.

[0010] Preferably, the introduction reflection surface is a mirror surface, and the light guide path includes a scattering reflection surface inside thereof for scattering and reflecting the light from the introduction reflection surface to guide the light.

[0011] Preferably, the scattering and reflecting surface has linear fine irregularities extending along a surface parallel to both a depth direction to the scattering and reflecting surface and a depth direction from the scattering and reflecting surface in the light guide.

[0012] Preferably, the import reflection surface is arranged on the optical axis of the first-order diffraction beam at a position closer to the front side than the focusing position of the first-order diffraction beam, and the first-order diffraction beam is focused between the reflection surface on which the light from the import reflection surface in the light guide path is directly incident and the import reflection surface.

[0013] Preferably, the light absorbing portion has a concave-convex surface with a light absorbing film provided on the surface.

[0014] Preferably, the light shielding unit further includes a cooling flow path disposed near the light absorbing portion and through which a coolant flows.

[0015] Preferably, a cooling flow path through which a coolant flows is also arranged near the light guide path.

[0016] Preferably, in the shading unit, around the 0th-order diffraction beam opening and the import reflection surface, a 2nd-order light absorption portion for absorbing the 2nd-order diffraction beam from the light modulator is provided on the outer surface extending in a direction perpendicular to the optical axis of the 0th-order diffraction beam.

[0017] Preferably, the light guiding path extends parallel to a plane perpendicular to the optical axis of the 0th-order diffracted light beam.

[0018] Preferably, the light guiding path bends and extends around the 0th-order diffraction beam opening to surround the 0th-order diffraction beam opening.

[0019] Preferably, the introduction reflection surface is a portion of a circumferentially inclined surface that surrounds the opening of the 0th-order diffracted beam and that moves away from the optical axis of the 0th-order diffracted beam as it moves from the front side toward the back side in the optical axis direction of the 0th-order diffracted beam. The light guide path is a portion of an annular space that radially extends outward from the circumferentially inclined surface.

[0020] Preferably, the 0th-order diffracted beam and the 1st-order diffracted beam are planar beams that expand in the vertical direction. The light guide includes a pair of parallel reflective surfaces that expand in the vertical direction and are inclined relative to the optical axis of the 0th-order diffracted beam. The introduction reflective surface is the end of one of the pair of reflective surfaces on the side closest to the 0th-order diffracted beam. Light from the introduction reflective surface is guided within the light guide while reciprocating between the pair of reflective surfaces.

[0021] The introduction reflection surface and the light guide path are arranged on a cutting block formed by cutting.

[0022] Preferably, the shading unit blocks multiple first-order diffracted light beams from the light modulator. The shading unit includes multiple shading portions corresponding to the multiple first-order diffracted light beams. Each shading portion includes the introduction reflective surface and the light guide path. The relative positions of the multiple shading portions relative to the opening for the zero-order diffracted light beam are variable.

[0023] The present invention also relates to a three-dimensional modeling device. A preferred embodiment of the present invention comprises: the aforementioned optical device; a laser light source for emitting the laser light toward the optical device; and a scanning unit for scanning the modulated light beam from the optical device onto the object to be irradiated, the scanning unit for scanning the modulated light beam over a modeling material.

[0024] The above-mentioned object and other objects, features, aspects and advantages will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1It is a diagram showing the structure of a three-dimensional modeling apparatus having an optical device according to the first embodiment.

[0026] Figure 2 It is a diagram showing the structure of a projection optical system.

[0027] Figure 3 It is a diagram showing the structure of a projection optical system.

[0028] Figure 4 It is a perspective view of the light shielding unit.

[0029] Figure 5 It is a perspective view showing the interior of the light shielding unit.

[0030] Figure 6 It is the front view of the shading unit.

[0031] Figure 7 It is a perspective view showing the interior of the light shielding unit.

[0032] Figure 8 It is a front view showing one light-shielding portion in an enlarged manner.

[0033] Figure 9 It is a perspective view showing an enlarged view of the first internal reflection surface.

[0034] Figure 10 It is the main view of the third component.

[0035] Figure 11 It is a diagram showing the configuration of a projection optical system of an optical device according to a second embodiment.

[0036] Figure 12 It is a diagram showing the structure of a projection optical system.

[0037] Figure 13 It is a perspective view of the light shielding unit.

[0038] Figure 14 It is a perspective view showing the interior of the light shielding unit.

[0039] Figure 15 is a cross-sectional view of a light shielding unit.

[0040] Figure 16 It is a cross-sectional view showing one light-shielding portion in an enlarged manner.

[0041] Figure 17 It is a perspective view of a light shielding unit according to a third embodiment.

[0042] Figure 18 It is a perspective view showing the interior of the light shielding unit.

[0043] Figure 19 is a cross-sectional view of a light shielding unit. DETAILED DESCRIPTION

[0044] Figure 1 This diagram shows the structure of a three-dimensional modeling apparatus 1 including an optical device 12 according to the first embodiment of the present invention. The three-dimensional modeling apparatus 1 is an SLM (Selective Laser Melting)-type three-dimensional modeling apparatus that melts a powdered or paste-like modeling material by irradiating it with a modulated laser beam, thereby performing three-dimensional modeling. Modeling materials include, for example, metals, engineering resins, ceramics, and synthetic resins. The modeling material can be composed of a variety of materials.

[0045] The three-dimensional modeling device 1 has a laser light source 11, an optical device 12, a scanning unit 13, and a material supply mechanism 14. In the three-dimensional modeling device 1, the laser L31 emitted from the laser light source 11 is guided to the scanning unit 13 through the optical device 12, and is scanned on the modeling material 91 in the modeling space 140 of the material supply mechanism 14 by the scanning unit 13. As a result, the portion of the modeling material 91 irradiated with the laser is melted. Then, by repeatedly supplying the modeling material 91 to the modeling space 140 and scanning the laser on the modeling material 91, a three-dimensional modeled object is formed. Figure 1 In order to facilitate understanding of the drawings, each structure of the optical device 12 is surrounded by a two-dot chain line.

[0046] In the three-dimensional modeling apparatus 1, a control unit (not shown) controls components such as a laser light source 11, an optical device 12 (e.g., a light modulator 22 described later), a scanning unit 13, and a material supply mechanism 14 based on design data (e.g., CAD data) of a predetermined three-dimensional object to be manufactured. This control unit is, for example, a conventional computer having a processor, memory, input / output units, and a bus.

[0047] The laser light source 11 emits laser light L31 toward the optical device 12. The laser light source 11 is, for example, a fiber laser light source. The wavelength of the laser light L31 is, for example, 1.070 μm.

[0048] The optical device 12 modulates the laser light L31 from the laser light source 11 into a modulated light beam L33 and irradiates the modulated light beam L33 toward the scanning unit 13. The optical device 12 includes an illumination optical system 21, a light modulator 22, and a projection optical system 23. As described below, the illumination optical system 21 and the projection optical system 23 each include optical elements such as a plurality of lenses.

[0049] The illumination optical system 21 shapes the laser light L31 from the laser light source 11 into a predetermined shape and guides it to the light modulator 22. In the present embodiment, the illumination optical system 21 shapes the laser light L31 into a roughly linear parallel light beam L32 that is longer in one direction (hereinafter referred to as the "long axis direction") and guides it to the light modulator 22. In other words, the cross-sectional shape of the parallel light beam L32 is a roughly linear shape that is longer in the long axis direction and shorter in the short axis direction perpendicular to the long axis direction. The cross-sectional shape of the parallel light beam L32 refers to the shape of the parallel light beam L32 on a plane perpendicular to the direction of travel of the parallel light beam L32. In the following description, the cross section of light refers to the cross section of the light on a plane perpendicular to the direction of travel of the light, as described above. The cross-sectional shape of the parallel light beam L32 can also be regarded as a roughly rectangular shape. The size of the cross section of the parallel light beam L32 is the same at any position in the direction of travel of the parallel light beam L32. The shape of the irradiation area of ​​the parallel light beam L32 on the light modulator 22 is, for example, a substantially linear shape (or a substantially rectangular shape) with a length of 28 mm in the major axis direction and a length of 1 mm in the minor axis direction.

[0050] The light modulator 22 modulates the parallel beam L32 from the illumination system 21 into a modulated beam L33 and guides it to the projection system 23. As the light modulator 22, for example, a one-dimensional spatial light modulation element such as a Grating Light Valve (registered trademark) can be used.

[0051] The optical modulator 22 has a plurality of modulator elements (not shown) arranged in a direction corresponding to the long axis direction of the parallel light beam L32. Each modulator element has a plurality of bands arranged adjacent to each other. In the optical modulator 22, light modulation using a diffraction grating is performed, and the reflected light from each modulator element switches between a 0th-order diffracted light beam (i.e., regular reflected light) and a non-0th-order diffracted light beam. The 0th-order diffracted light beam emitted from the optical modulator 22 is guided toward the scanning unit 13 through the projection optical system 23. In addition, the non-0th-order diffracted light beam emitted from the optical modulator 22 is blocked and absorbed at a position further forward than the scanning unit 13 by the shading unit 24 described later, which is provided in the projection optical system 23.

[0052] The projection optical system 23 condenses the modulated light beam L33 from the light modulator 22 and guides it to the scanner 13. In other words, the scanner 13 is the target to which the modulated light beam L33 is guided by the optical device 12. The modulated light beam L33 is irradiated onto the irradiation surface 131 of the scanner 13.

[0053] The scanning unit 13 reflects the modulated light beam L33 from the projection optical system 23 of the optical device 12 and scans it on the molding material 91 within the molding space 140 of the material supply mechanism 14. As the scanning unit 13, for example, a galvano scanner or a polygonal laser scanner can be used. In this embodiment, the scanning unit 13 is a galvano scanner having a galvano mirror 132 and a galvano motor (not shown), and the reflecting surface of the galvano mirror 132 serves as the irradiation surface 131. In the scanning unit 13, the galvano mirror 132 is rotated by the galvano motor, thereby changing the direction of travel of the modulated light beam L33 reflected by the galvano mirror 132. As a result, the modulated light beam L33 irradiated on the molding material 91 is scanned in a scanning direction corresponding to the short-axis direction of the modulated light beam L33.

[0054] The material supply mechanism 14 has a shaping section 141 and a supply section 142. The shaping section 141 has a first cylinder 143 and a first piston 144. The first cylinder 143 is a cylindrical component extending in the up-down direction. The shape of the internal space of the first cylinder 143 when viewed from above is, for example, roughly rectangular. The first piston 144 is a roughly flat or roughly columnar component accommodated in the internal space of the first cylinder 143, and its shape when viewed from above is roughly the same as that of the internal space of the first cylinder 143. The first piston 144 is capable of moving in the up-down direction in the internal space of the first cylinder 143. In the shaping section 141, the three-dimensional space enclosed by the inner side surface of the first cylinder 143 and the upper surface of the first piston 144 becomes a shaping space 140 for performing three-dimensional shaping based on the modulated light beam L33.

[0055] The supply unit 142 includes a second cylinder 145, a second piston 146, and a scraper 147. The second cylinder 145 is a cylindrical member extending in the vertical direction and is located adjacent to the side of the first cylinder 143. The internal space of the second cylinder 145 has a generally rectangular shape when viewed from above. The second piston 146 is a generally flat or columnar member housed within the internal space of the second cylinder 145, and its shape when viewed from above is generally the same as that of the internal space of the second cylinder 145. The second piston 146 is movable vertically within the internal space of the second cylinder 145. In the supply unit 142, the three-dimensional space defined by the inner surface of the second cylinder 145 and the upper surface of the second piston 146 serves as a storage space for the predetermined molding material 91 to be supplied to the molding unit 141. The scraper 147 is a rod-shaped member (e.g., generally cylindrical) that extends horizontally across the upper opening of the second cylinder 145. The scraper 147 is movable in the horizontal direction along the upper end surface of the second cylinder 145 .

[0056] In the supply unit 142, the second piston 146 rises a predetermined distance, lifting the molding material 91 in the second cylinder 145 upward. Then, the scraper 147 moves from the second cylinder 145 toward the first cylinder 143, thereby supplying the molding material 91 protruding upward from the upper end surface of the second cylinder 145 into the molding space 140 of the molding unit 141. The upper surface of the molding material 91 held in the molding space 140 is positioned at a predetermined height (e.g., the same height as the upper end surface of the first cylinder 143).

[0057] In the three-dimensional modeling apparatus 1, the modeling material 91 within the modeling space 140 is scanned with the modulated light beam L33. As a result, the surface portion of the modeling material 91 within the modeling space 140, irradiated by the modulated light beam L33, melts, forming a portion corresponding to one layer when the three-dimensional modeling object is divided into multiple layers stacked in the vertical direction. When the scanning of the modeling material 91 within the modeling space 140 by the modulated light beam L33 is completed, the first piston 144 descends a predetermined distance. Then, as described above, the modeling material 91 is supplied from the supply unit 142 to the modeling space 140, and the modulated light beam L33 is scanned. In the three-dimensional modeling apparatus 1, by repeatedly supplying the modeling material 91 to the modeling space 140 and scanning the modeling material 91 within the modeling space 140 with the modulated light beam L33, a three-dimensional modeling object is formed within the modeling space 140.

[0058] Next, refer to Figure 2 and Figure 3 The structure of the projection optical system 23 of the optical device 12 will be described. Figure 2 In FIG, the v-order diffracted beam L35 of the modulated beam L33 is depicted by a solid line, and the 1-order diffracted beam L36 is depicted by a dotted line. Figure 2 In FIG, the optical path of the modulated light beam L33 is shown in such a manner that the short axis direction of the modulated light beam L33 is consistent with the direction perpendicular to the paper surface. Figure 2 In the figure, the long axis direction of the modulated light beam L33 is consistent with the up and down direction in the figure. Figure 3 In FIG, the optical path of the modulated light beam L33 is shown in such a manner that the long axis direction of the modulated light beam L33 is consistent with the direction perpendicular to the paper surface. Figure 3 In the figure, the short axis direction of the modulated light beam L33 is consistent with the up and down direction in the figure. Figure 3 middle, Figure 2 The 0th-order diffraction beam L35 and the 1st-order diffraction beam L36 overlap.

[0059] The projection optical system 23 includes a first lens 231, a second lens 232, a third lens 233, and a light shielding unit 24. The first lens 231 and the second lens 232 are, for example, spherical convex lenses, and the third lens 233 is, for example, a cylindrical convex lens.

[0060] The second lens 232 and the third lens 233 are located closer to the direction of travel of the modulated light beam L33 (i.e., on the side of the modulated light beam L33 traveling from the light modulator 22 toward the scanning unit 13) than the first lens 231. In other words, the second lens 232 and the third lens 233 are located closer to the scanning unit 13 than the first lens 231 in the optical path of the modulated light beam L33. The third lens 233 is located closer to the direction of travel of the modulated light beam L33 than the second lens 232. In the projection optical system 23, the first lens 231, the second lens 232, and the third lens 233 make the modulation surface of the light modulator 22 and the irradiation surface 131 of the scanning unit 13 optically conjugate in the major and minor axis directions.

[0061] The shading unit 24 is positioned between the first lens 231 and the second lens 232 on the optical path of the modulated light beam L33. The shading unit 24 allows the 0th-order diffracted light beam L35 from the optical modulator 22 to pass through, while blocking the 1st-order diffracted light beam L36. The shading unit 24 is positioned near the focal position of the 0th-order diffracted light beam L35 and blocks the two 1st-order diffracted light beams L36 focused on either side of the long axis of the 0th-order diffracted light beam L35. The 1st-order diffracted light beam L36 blocked by the shading unit 24 is focused in both the long axis and the short axis. Furthermore, the shading unit 24 blocks non-0th-order diffracted light beams (not shown) of the second and higher orders from the optical modulator 22.

[0062] In addition, in the projection optical system 23, the types of the first lens 231, the second lens 232, and the third lens 233 can be changed in various ways, and optical elements other than those described above can be added. In addition, in the actual projection optical system 23, each lens and the light shielding unit 24 are arranged close to each other.

[0063] Next, refer to Figures 4 to 7 The light shielding unit 24 will be described. Figure 4 It is a perspective view showing the appearance of the light shielding unit 24 . Figure 5 It is a perspective view showing the interior of the light shielding unit 24 . Figure 6 It is a front view of the light shielding unit 24. Figure 7 It is a perspective view showing the interior of the light shielding unit 24 .

[0064] The light shielding unit 24 is a substantially rectangular flat plate-shaped structure. The lengths of the light shielding unit 24 in the longitudinal and transverse directions are, for example, several tens of millimeters, and the thickness of the light shielding unit 24 (i.e., the depth when viewed from the front) is, for example, more than ten millimeters. A light shielding unit 24 is provided in the center portion when viewed from the front for receiving light from the light modulator 22 (see FIG. Figure 1) passes through the 0th order diffraction beam opening portion 240. The 0th order diffraction beam opening portion 240 is located near the focusing position of the 0th order diffraction beam on the optical axis J35 of the 0th order diffraction beam.

[0065] exist Figure 4 and Figure 5 In the figure, the optical axis J35 of the 0th order diffracted beam is represented by a dotted line. Figure 4 and Figure 5 In the figure, the optical axis J36 of the 1st order diffraction beam is also indicated by a dotted line. In addition, in the following description, the direction in which the optical axis J35 of the 0th order diffraction beam extends is also referred to as the "X direction". In addition, the two directions perpendicular to the X direction and orthogonal to each other are also referred to as the "Y direction" and the "Z direction". The Z direction is Figure 4 The light shielding unit 24 is a substantially flat plate-shaped structure extending in the Y and Z directions (ie, extending substantially perpendicularly to the X direction).

[0066] The two first-order diffracted beams enter the light shielding unit 24 from the (-X) side. The light shielding unit 24 has two light shielding portions 241 that respectively shield the two first-order diffracted beams. Furthermore, in the projection optical system 23, the number of first-order diffracted beams entering the light shielding unit 24 from the light modulator 22 is not limited to two, but may be three or more. That is, in the projection optical system 23, multiple first-order diffracted beams enter the light shielding unit 24, and the light shielding unit 24 has multiple light shielding portions 241 corresponding to the multiple first-order diffracted beams.

[0067] Each light shielding portion 241 includes a light introduction reflection surface 41, a light guide path 42, and a light absorbing portion 43. Figure 5 and Figure 7 In the figure, the light absorbing portion 43 is marked with parallel oblique lines. The light guide 42 is a passage (i.e., space) provided inside the light shielding unit 24. The introduction port 44, which is one end of the light guide 42, is arranged near the 0th order diffraction beam opening 240. The introduction reflection surface 41 is outside the light guide 42 and is arranged near the introduction port 44 and the 0th order diffraction beam opening 240. Figure 5 In the illustrated example, the introduction reflection surfaces 41 of the two light shielding portions 241 are arranged on the (+Z) side and the (−Z) side of the 0th-order diffracted beam opening portion 240 .

[0068] The introduction reflection surface 41 is positioned on the optical axis J36 of the first-order diffracted beam from the optical modulator 22, near the focal position of the first-order diffracted beam. The introduction reflection surface 41 reflects the first-order diffracted beam and guides it toward the introduction port 44 of the optical guide 42. The reflection direction of the first-order diffracted beam by the introduction reflection surface 41 is deviated from the incident direction of the first-order diffracted beam with respect to the introduction reflection surface 41 and is also away from the optical axis J35 of the zero-order diffracted beam. In other words, the introduction reflection surface 41 guides the first-order diffracted beam in a direction that is significantly separated from the zero-order diffracted beam.

[0069] The first-order diffracted light beam reflected by the introduction reflection surface 41 enters the interior of the light guide 42 from the introduction port 44. The light guide 42 is a space surrounded by a light shielding member and extends parallel to the YZ plane (i.e., a plane perpendicular to the optical axis J35 of the 0th-order diffracted light beam). The light guide 42 allows the light introduced from the introduction port 44 (hereinafter also referred to as "introduced first-order light") to pass along the YZ plane. Figure 6 The light is diffused by arrows 361 in FIG. 4 and guided to the terminal portion, which is the end portion opposite to the introduction port 44. The light absorbing portion 43 absorbs the introduced primary light guided by the light guide 42 at the terminal portion of the light guide 42.

[0070] Next, the detailed structure of the light shielding portion 241 will be described. The following description focuses on one light shielding portion 241, which includes the introduction reflection surface 41 located on the (-Z) side of the 0th-order diffracted beam opening 240. The structures of the other light shielding portions 241 are approximately point-symmetrical with the structure of the aforementioned light shielding portion 241, centered about the optical axis J35 of the 0th-order diffracted beam, when viewed from the front.

[0071] In this light-shielding portion 241, the introduction reflection surface 41 is a plane extending approximately parallel to the Z direction, and is an inclined surface that is inclined toward the (+X) side as it is inclined toward the (+Y) side. The inclination angle of the introduction reflection surface 41 relative to the X direction and the inclination angle relative to the Y direction are respectively approximately 45°. The introduction reflection surface 41 is, for example, a mirror surface. Here, the mirror surface refers to a reflection surface on which the incident first-order diffracted light beam is substantially not scattered but is totally reflected. The same is true for the light-shielding units 24a and 24b described later. The first-order diffracted light beam is reflected toward the (+Y) direction at the approximate center of the introduction reflection surface 41 and toward the introduction port 44 of the light guide path 42. Substantially all the light amount of the first-order diffracted light beam reflected by the introduction reflection surface 41 is guided toward the guide port 44 and introduced into the interior of the light guide path 42.

[0072] The light guide 42 curves and extends around the 0th-order diffracted beam opening 240 so as to surround it. Specifically, the light guide 42 extends from the (-Z) side of the 0th-order diffracted beam opening 240 in the (+Y) direction, curves at a substantially right angle to extend in the (+Z) direction, curves at a substantially right angle to extend in the (-Y) direction, passes through the (+Z) side of the 0th-order diffracted beam opening 240, and extends to the (-Y) side of the 0th-order diffracted beam opening 240. In the light shielding unit 24, the two light guides 42 surround the 0th-order diffracted beam opening 240 substantially entirely.

[0073] A first internal reflection surface 421, a second internal reflection surface 422, and a third internal reflection surface 423 are provided within the light guide 42. The first internal reflection surface 421 is located on the (+Y) side of the introduction reflection surface 41 at the curved portion of the light guide 42. The second internal reflection surface 422 is located on the (+Z) side of the first internal reflection surface 421 at the curved portion of the light guide 42. The third internal reflection surface 423 is located on the (-Y) side of the second internal reflection surface 422 at the terminal end of the light guide 42. The introduced primary light, which is reflected by the introduction reflection surface 41 and introduced into the light guide 42, is sequentially reflected by the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 and guided toward the light absorption portion 43.

[0074] The first internal reflection surface 421 is a plane extending approximately parallel to the X direction and is inclined toward the (+Z) side as it approaches the (+Y) side. The first internal reflection surface 421 has an inclination angle of approximately 45° with respect to the Y direction and an inclination angle of approximately 45° with respect to the Z direction. The introduced first-order light traveling from the introduction reflection surface 41 in the (+Y) direction directly enters the first internal reflection surface 421 without passing through other reflection surfaces. The introduced first-order light entering the first internal reflection surface 421 from the introduction reflection surface 41 is reflected in the (+Z) direction by the first internal reflection surface 421 and travels toward the second internal reflection surface 422. The second internal reflection surface 422 is a plane extending approximately parallel to the X direction and is inclined toward the (+Z) side as it approaches the (-Y) side. The second internal reflection surface 422 has an inclination angle of approximately 45° with respect to the Y direction and an inclination angle of approximately 45° with respect to the Z direction. The introduced first-order light incident on the second internal reflection surface 422 from the first internal reflection surface 421 is reflected in the (−Y) direction by the second internal reflection surface 422 and travels toward the third internal reflection surface 423 .

[0075] The third internal reflection surface 423 is a plane extending approximately parallel to the Z direction and is inclined toward the (+X) side as it approaches the (-Y) side. The third internal reflection surface 423 has an inclination angle of approximately 45° with respect to the X and Y directions, respectively. The introduced primary light incident on the third internal reflection surface 423 from the second internal reflection surface 422 is reflected by the third internal reflection surface 423 in the (+X) direction and directed toward the light absorption portion 43, which is the (+X) side surface of the light guide 42. As described above, since the light guide 42 is surrounded by the light shielding member, the introduced primary light directed from the introduction port 44 toward the light absorption portion 43 is prevented from leaking from the light guide 42 to the exterior of the light shielding unit 24.

[0076] The light-absorbing portion 43 is a flat surface approximately perpendicular to the X-direction, with a light-absorbing film provided on its surface. This film can be a film or sheet-like member formed from a material that readily absorbs light, or it can be a coating formed by applying a material that readily absorbs light. The introduced primary light reflected by the third internal reflection surface 423 is irradiated onto the light-absorbing portion 43. In other words, the light-absorbing portion 43 has an illuminated surface that is illuminated by the introduced primary light that has passed through the light guide 42. In the light-absorbing portion 43, the introduced primary light from the light guide 42 is absorbed by the light-absorbing film.

[0077] Figure 8 FIG. 2 is an enlarged front view showing one of the light shielding portions 241. Figure 8 In FIG, the first-order diffracted light beam L36 incident on the introduction reflection surface 41 is depicted by a solid line, and the optical axis J36 of the first-order diffracted light beam L36 is depicted by a dashed line. Figure 8 In the figure, the introduced first-order light L37 without scattering etc. in the first internal reflection surface 421, the second internal reflection surface 422 and the third internal reflection surface 423 is depicted by a double-dashed line, and the optical axis J37 of the introduced first-order light L37 is depicted by a dotted line.

[0078] As described above, the introduction reflection surface 41 is arranged near the focus position 360 of the first-order diffracted light beam L36. Figure 8In the example shown, the introduction reflective surface 41 is positioned on the optical axis J36 of the first-order diffracted beam L36, closer to the front side (i.e., on the optical modulator 22 side of the optical axis J36 of the first-order diffracted beam L36) than the focal position 360 of the first-order diffracted beam L36. The first-order diffracted beam L36, reflected by the introduction reflective surface 41, is then focused at the focal position 360 between the introduction reflective surface 41 and the first internal reflection surface 421. In other words, the focal position 360 of the first-order diffracted beam L36 is located between the introduction reflective surface 41 and the first internal reflection surface 421. The focal position 360 of the first-order diffracted beam L36 can also be located between the introduction reflective surface 41 and the introduction port 44 of the light guide 42 (i.e., outside the light guide 42), or between the introduction port 44 and the first internal reflection surface 421 (i.e., inside the light guide 42). Alternatively, the focal position 360 of the first-order diffracted beam L36 can be located on the introduction port 44.

[0079] The introduced primary light L37, introduced from the introduction port 44 and directed toward the first internal reflection surface 421, then travels in the (+Y) direction within the light guide 42, expanding its area in a cross section perpendicular to the optical axis J37 (i.e., diffusing). After being reflected by the first internal reflection surface 421, it then diffuses in a substantially similar manner, being guided toward the light absorption portion 43 via the second internal reflection surface 422 and the third internal reflection surface 423. Consequently, the area illuminated by the introduced primary light L37 in the light absorption portion 43 increases, reducing the energy density of the introduced primary light L37. Consequently, a temperature rise in the light absorption portion 43 (particularly a local temperature rise in the area illuminated by the introduced primary light L37) can be suppressed.

[0080] To further increase the area illuminated by the primary light L37, the light absorbing portion 43 may be provided with a convex or concave surface in the X direction on the surface where the light absorbing film is provided (i.e., the surface on the (-X) side). The height of this convex or concave surface (i.e., the height in the X direction) is, for example, approximately several millimeters. The light absorbing film is provided along this convex or concave surface. By providing the surface where the light absorbing film is provided with a convex or concave surface, the area illuminated by the primary light L37 is further increased, thereby further suppressing the temperature rise of the light absorbing portion 43.

[0081] Furthermore, to further increase the area illuminated by the introduced primary light L37 in the light absorbing section 43, microscopic projections and depressions can be provided on the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423. In this case, the introduced primary light L37 incident on the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 is reflected while being scattered, further diffusing the introduced primary light L37 traveling within the light guide 42 toward the light absorbing section 43. In other words, by configuring the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 as scattering reflection surfaces in the light shielding unit 24, the diffusion of the introduced primary light L37 traveling within the light guide 42 is promoted, thereby further increasing the area illuminated by the introduced primary light L37 in the light absorbing section 43. As a result, the temperature rise of the light absorbing section 43 can be further suppressed.

[0082] Figure 9 4 is an enlarged perspective view showing the first internal reflection surface 421 provided with fine concavoconvexo 424. Figure 9 In the example shown, the fine asperities 424 are linear asperities extending in the Y and Z directions along the first internal reflection surface 421 (i.e., hairlines extending toward the (+Z) side as they approach the (+Y) side). In other words, the fine asperities 424 extend along a surface parallel to both the direction in which the light guide 42 extends toward the first internal reflection surface 421 (i.e., the Y direction) and the direction in which the light guide 42 extends from the first internal reflection surface 421 (i.e., the Z direction). In other words, the fine asperities 424 extend along a surface parallel to both the depth direction of the light guide 42 to the first internal reflection surface 421 (i.e., the Y direction) and the depth direction from the first internal reflection surface 421 (i.e., the Z direction). A plurality of these linear fine asperities 424 are arranged in a direction substantially perpendicular to the longitudinal direction of the first internal reflection surface 421. The height of the fine irregularities 424 on the first internal reflection surface 421 (that is, the amount of protrusion or depression relative to the surrounding area) is, for example, approximately several μm.

[0083] The introduced first-order light L37 incident on the first internal reflection surface 421 (see Figure 8 ) is scattered primarily in the X direction by the linear fine asperities 424, and is hardly scattered in the direction in which the introduced primary light L37 returns to the incident side of the first internal reflection surface 421 (i.e., the (-Y) direction). Therefore, the cross-sectional area of ​​the introduced primary light L37 reflected by the first internal reflection surface 421 can be further increased, and the reflected light from the first internal reflection surface 421 can be prevented from returning to the guide port 44 and leaking out of the light guide path 42.

[0084] The fine asperities provided on the second internal reflection surface 422 are, for example, linear asperities extending in the Y and Z directions along the second internal reflection surface 422 (i.e., extending toward the (+Z) side as it approaches the (-Y) side). Therefore, the introduced primary light L37 incident on the second internal reflection surface 422 is primarily scattered in the X direction and is hardly scattered in the direction in which the introduced primary light L37 returns to the incident side of the second internal reflection surface 422 (i.e., the (-Z) direction). Consequently, the cross-sectional area of ​​the introduced primary light L37 reflected by the second internal reflection surface 422 can be further increased, and the reflected light from the second internal reflection surface 422 can be prevented from returning to the guide port 44 and leaking out of the light guide path 42.

[0085] The fine asperities provided on the third internal reflection surface 423 are, for example, linear asperities extending in the X and Y directions along the third internal reflection surface 423 (i.e., extending toward the (+X) side as they extend toward the (-Y) side). Therefore, the introduced primary light L37 incident on the third internal reflection surface 423 is primarily scattered in the Z direction and is hardly scattered in the direction in which the introduced primary light L37 returns to the incident side of the third internal reflection surface 423 (i.e., the (+Y) direction). Consequently, the cross-sectional area of ​​the introduced primary light L37 reflected by the third internal reflection surface 423 can be further increased, and the reflected light from the third internal reflection surface 423 can be prevented from returning to the guide port 44 and leaking out of the light guide path 42.

[0086] Furthermore, when the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 are configured as scattering reflection surfaces, a portion of the introduced first-order light L37 can be incident on the light absorbing portion 43 and absorbed before reaching the third internal reflection surface 423. Furthermore, in the light shielding unit 24, not all of the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 need be scattering reflection surfaces. By configuring one or more of the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 as scattering reflection surfaces, the temperature increase of the light absorbing portion 43 can be further suppressed as described above.

[0087] Furthermore, in the light shielding unit 24, the introduction reflection surface 41 may be a scattering reflection surface. In this case, preferably, at least 86.5% of the light reflected by the introduction reflection surface 41, based on the light quantity, is guided toward the guide port 44 and introduced into the interior of the light guide path 42. More preferably, substantially all of the light is guided toward the guide port 44 and introduced into the interior of the light guide path 42. By configuring the introduction reflection surface 41 as a scattering reflection surface, the cross-sectional area of ​​the introduced first-order light L37 can be increased, similarly to the above description, thereby further suppressing the temperature rise of the light absorbing portion 43. Furthermore, when the light reflected and diffused from the introduction reflection surface 41 is incident on the first internal reflection surface 421, it is preferable that the overall cross-sectional area of ​​the incident light is smaller than that of the first internal reflection surface 421, so that substantially all of the incident light is incident on the first internal reflection surface 421.

[0088] like Figure 4 As shown, the shading unit 24 includes a first member 251, a second member 252 and a third member 253. Figure 5 and Figure 7 In FIG, the first member 251 is omitted. Figure 7 , the upper ends of the second member 252 and the third member 253 are omitted from the illustration. The first member 251 and the third member 253 are roughly rectangular flat plate-shaped members having a through hole corresponding to the 0th-order diffraction beam opening 240 provided in the center. The second member 252 is a roughly rectangular frame-shaped member having a partition 254 forming the light guide path 42 provided on the inner side. The first member 251, the second member 252, and the third member 253 are arranged in this order on the optical axis J35 of the 0th-order diffraction beam from the (-X) side (i.e., the direction in which the optical axis J35 of the 0th-order diffraction beam extends, i.e., the near front side in the optical axis direction), and are fixed to each other to form the light shielding unit 24.

[0089] The first member 251, the second member 252, and the third member 253 are light-blocking members that prevent light from the optical modulator 22 from passing through. By blocking the gaps in the second member 252 with the first member 251 and the third member 253 from both sides in the X direction, a light guide 42 surrounded by the light-blocking members is formed. The first member 251, the second member 252, and the third member 253 are formed from a material that easily reflects light from the optical modulator 22 and has relatively high thermal conductivity. The first member 251, the second member 252, and the third member 253 are formed, for example, from copper (Cu). Alternatively, a thin film of gold (Au) may be provided on the aforementioned reflective inlet surface 41, etc. Furthermore, the materials of the first member 251, the second member 252, and the third member 253 may be modified as appropriate.

[0090] The first member 251 is, for example, a roughly flat copper plate extending in the Y and Z directions, with a through-hole provided in the center. This through-hole corresponds to the aforementioned 0th-order diffracted beam opening 240 and exposes the reflective inlet surface 41 of each light-shielding portion 241 on the (-X) side of the light-shielding unit 24. The main surface of the (-X) side of the first member 251 is a roughly flat surface extending roughly perpendicular to the X direction (i.e., extending roughly perpendicular to the optical axis J35 of the 0th-order diffracted beam), and is provided with a light-absorbing film. This light-absorbing film can be a film or sheet formed from a material that readily absorbs light, or it can be a coating formed by applying a material that readily absorbs light.

[0091] On the (-X)-side principal surface of the first member 251, the second-order diffracted beam and third-order and higher-order diffracted beams from the light modulator 22 are incident on the (+Z) and (-Z) sides of the through-hole and are absorbed by the light-absorbing film. Thus, on the (-X)-side principal surface of the first member 251 (i.e., the (-X)-side outer surface of the light shielding unit 24), a second-order light-absorbing portion 255 is provided around the 0th-order diffracted beam opening 240 and the introduction reflection surface 41 to absorb higher-order diffracted beams, including the second-order diffracted beam.

[0092] The second member 252 is, for example, a cut block formed by cutting a substantially flat copper plate extending in the Y and Z directions. A gap serving as the light guide 42 is formed in the second member 252. In addition, the second member 252 includes an introduction reflection surface 41, a first internal reflection surface 421, a second internal reflection surface 422, and a third internal reflection surface 423. The first internal reflection surface 421 has fine concave and convex portions 424 (see FIG. 1 ). Figure 9 ) is formed, for example, by performing fine line processing during the cutting process of the second member 252. This can shorten the time required for manufacturing the second member 252, compared to the case where fine irregularities are formed on the first internal reflection surface 421 by sandblasting or the like after the cutting process of the second member 252 is completed.

[0093] The third member 253 is, for example, a copper plate having a substantially flat shape extending in the Y and Z directions, with a through-hole provided in the center. This through-hole corresponds to the aforementioned zero-order diffracted beam opening 240. As described above, the (-X)-side principal surface of the third member 253 (i.e., the principal surface facing the light guide 42) forms the light absorbing portion 43, which is provided with a light absorbing film.

[0094] In the light shielding unit 24, a light-absorbing film may be provided on the (+X)-side principal surface of the first member 251 (i.e., the principal surface facing the light guide 42). Alternatively, the (+X)-side principal surface of the first member 251 may be a reflective surface. The first member 251 and the third member 253 may also be formed by cutting, similar to the second member 252.

[0095] Figure 10 253 is a front view showing the third member 253. Figure 10 , the light guide path 42 is also indicated by a double-dashed line. A cooling flow path 256 is provided inside the third member 253. The cooling flow path 256 is arranged near the light absorbing portion 43 (i.e., the main surface of the third member 253 on the (-X) side). A coolant such as water flows inside the cooling flow path 256. As a result, the temperature rise of the light absorbing portion 43 can be further suppressed. In addition, the vicinity of the light absorbing portion 43 mentioned above refers to a range in which the light absorbing portion 43 can be effectively cooled by the coolant flowing in the cooling flow path 256.

[0096] Furthermore, the cooling flow path 256 preferably overlaps with the light guide path 42 of each light shielding portion 241 when viewed from the front. By also arranging the cooling flow path 256 near the light guide path 42, even if a temperature rise occurs in the light guide path 42 due to scattering of the introduced primary light, this temperature rise can be effectively suppressed. The area near the light guide path 42 mentioned above refers to an area where the coolant flowing through the cooling flow path 256 can effectively cool the light guide path 42. In the light shielding unit 24, a temperature sensor may be arranged near the cooling flow path 256 to measure the temperature of the light absorbing portion 43 and the light guide path 42. This makes it easy to detect abnormal temperature rise in the light shielding unit 24.

[0097] As described above, the optical device 12 includes an illumination system 21, a light modulator 22, and a projection system 23. The illumination system 21 shapes the laser light emitted from the laser light source 11 into a predetermined shape. The light modulator 22 modulates the laser light shaped by the illumination system 21 into a modulated light beam L33. The projection system 23 guides the modulated light beam L33 toward an object (in the above example, the scanner 13). The projection system 23 includes a light shielding unit 24 that allows the 0th-order diffracted light beam L35 from the light modulator 22 to pass through and blocks the 1st-order diffracted light beam L36.

[0098] The light shielding unit 24 includes a 0th-order diffracted beam opening 240, an introduction reflection surface 41, a light guide 42, and a light absorption portion 43. The 0th-order diffracted beam opening 240 is located near the focal position of the 0th-order diffracted beam L35 on the optical axis J35 of the 0th-order diffracted beam L35, allowing the 0th-order diffracted beam L35 to pass through. The introduction reflection surface 41 is located near the focal position of the 1st-order diffracted beam L36 on the optical axis J36 of the 1st-order diffracted beam L36 and is located near the 0th-order diffracted beam opening 240. The introduction reflection surface 41 reflects the 1st-order diffracted beam L36 in a direction deviating from the incident direction of the 1st-order diffracted beam L36 and away from the optical axis J35 of the 0th-order diffracted beam L35. The light guide 42 includes an introduction port 44 for light from the introduction reflection surface 41 to enter, and guides the light introduced from the introduction port 44 (i.e., the introduced 1st-order light). The light guide 42 is surrounded by a light shielding member. The light absorbing portion 43 absorbs the light diffused and guided by the light guide 42 .

[0099] In the light shielding unit 24, the introduced primary light is guided toward the light absorbing portion 43 via the light guide 42, which is surrounded by a light shielding member. This prevents light from leaking from the light shielding unit 24. Furthermore, by diffusing the introduced primary light within the light guide 42 while guiding it toward the light absorbing portion 43, the energy density of the introduced primary light that strikes the light absorbing portion 43 can be reduced, even when the energy density of the laser light emitted from the laser light source 11 is high. As a result, the temperature rise of the light shielding unit 24 caused by light absorption by the light absorbing portion 43 can be suppressed, thereby preventing or suppressing temperature increases in optical components and the like surrounding the light shielding unit 24. Furthermore, since the required absorbance of the light absorbing portion 43 can be lowered, the degree of freedom in selecting the light absorbing film used in the light absorbing portion 43 is increased. Consequently, by using relatively inexpensive, long-lived light absorbing films, rather than expensive, films with very high absorbance, the manufacturing cost of the light shielding unit 24 can be reduced and its life extended.

[0100] As described above, the introduction reflection surface 41 is preferably a mirror surface. This prevents scattering of the first-order diffracted light beam L36 in the introduction reflection surface 41, thereby preventing or suppressing a temperature rise on the front side (i.e., the side of the optical modulator 22 along the optical axis J36 of the first-order diffracted light beam L36) closer to the light guide 42. In addition, substantially all of the light of the first-order diffracted light beam L36 incident on the introduction reflection surface 41 can be introduced into the interior of the light guide 42. Therefore, it is possible to prevent or suppress the temperature rise of the optical elements and the like around the shading unit 24. In addition, as described above, the light guide 42 preferably has a scattering reflection surface (e.g., a first internal reflection surface 421) inside that scatters and reflects the light from the introduction reflection surface 41 to guide it. This promotes the diffusion of the introduced first-order light inside the light guide 42.

[0101] The scattering and reflecting surface (e.g., first internal reflection surface 421) preferably has linear fine irregularities 424 extending parallel to both the depth direction to and from the scattering and reflecting surface within the light guide 42. This prevents the introduced primary light reflected by the scattering and reflecting surface from returning in the direction of incidence and allows the introduced primary light to be scattered by the scattering and reflecting surface. Consequently, the diffusion of the introduced primary light within the light guide 42 can be appropriately promoted.

[0102] As described above, the introduction reflection surface 41 is preferably positioned forward of the focal position 360 of the first-order diffracted beam L36 on the optical axis J36 of the first-order diffracted beam L36. Consequently, the energy density of the first-order diffracted beam L36 on the introduction reflection surface 41 can be reduced compared to a case where the introduction reflection surface 41 is positioned at the focal position 360. Consequently, temperature increases and damage to the introduction reflection surface 41 can be suppressed.

[0103] Furthermore, in the light guide 42, the first-order diffracted light beam L36 is preferably focused between the reflective surface (i.e., the first internal reflection surface 421) on which the light from the introduction reflection surface 41 directly enters and the introduction reflection surface 41. This reduces the energy density of the introduced first-order light on the first internal reflection surface 421 compared to when the focus position 360 is located on the first internal reflection surface 421. Consequently, temperature increases and damage to the first internal reflection surface 421 can be suppressed. Furthermore, compared to when the focus position 360 is located closer to the light absorption section 43 than the first internal reflection surface 421 (e.g., between the first internal reflection surface 421 and the second internal reflection surface 422), the degree of diffusion of the introduced first-order light upon reaching the light absorption section 43 can be increased. Consequently, the energy density of the introduced first-order light striking the light absorption section 43 can be reduced, thereby suppressing temperature increases in the light shielding unit 24. Furthermore, the cross-sectional area of ​​the light passing through the introduction port 44 can be reduced. Consequently, an increase in the size of the introduction port 44 and the light shielding unit 24 can be suppressed.

[0104] Alternatively, in the light shielding unit 24, the introduction reflection surface 41 may be arranged at the focus position 360 of the first-order diffracted beam L36. In this case, the area of ​​the introduction reflection surface 41 can be reduced. Furthermore, since the gap between the first-order diffracted beam L36 and the zero-order diffracted beam L35 is increased, the first-order diffracted beam L36 can be easily separated from the zero-order diffracted beam L35.

[0105] The introduction reflection surface 41 can be positioned on the optical axis J36 of the first-order diffracted beam L36, further inward than the focal position 360 of the first-order diffracted beam L36 (i.e., on the optical axis J36 of the first-order diffracted beam L36, on the side opposite the optical modulator 22 across the focal position 360). In this case, the energy density of the first-order diffracted beam L36 on the introduction reflection surface can be reduced. As a result, temperature rise and damage to the introduction reflection surface can be suppressed. Furthermore, the introduction first-order light introduced from the introduction reflection surface 41 into the light guide 42 can be reliably prevented from focusing on any of the reflection surfaces within the light guide 42. Consequently, temperature rise and damage to the various reflection surfaces within the light guide 42 can be suppressed.

[0106] As described above, the light absorbing portion 43 preferably has a concave-convex surface with a light absorbing film formed on the surface. This increases the area of ​​the light absorbing portion 43 irradiated with the introduced primary light, thereby reducing the energy density of the introduced primary light irradiating the light absorbing portion 43. Consequently, the temperature rise of the light shielding unit 24 can be further suppressed.

[0107] As described above, the light shielding unit 24 preferably further includes a cooling flow path 256 disposed near the light absorbing portion 43 and through which a coolant flows. This allows the light absorbing portion 43 to be cooled, further suppressing temperature increases in the light shielding unit 24. Furthermore, a cooling flow path 256 through which a coolant flows is preferably also disposed near the light guide 42. This also allows the light guide 42 to be cooled, further suppressing temperature increases in the light shielding unit 24.

[0108] As described above, in the light shielding unit 24, it is preferable to provide a second-order light absorbing portion 255 for absorbing the second-order diffracted light beam from the light modulator 22 on the outer surface extending in a direction perpendicular to the optical axis J35 of the 0th-order diffracted light beam L35 around the 0th-order diffracted light beam opening 240 and the introduction reflection surface 41. This can prevent the light shielding unit 24 from becoming larger and can shield non-0th-order diffracted light beams of the second and higher orders.

[0109] As described above, the light guide 42 preferably extends parallel to a plane perpendicular to the optical axis J35 of the 0th-order diffracted light beam L35. This allows the light shielding unit 24 to be miniaturized in the direction in which the optical axis J35 extends.

[0110] As described above, the light guide 42 preferably bends and extends around the 0th-order diffracted beam opening 240 to surround the 0th-order diffracted beam opening 240. This allows the light shielding unit 24 to be miniaturized when viewed from the front (i.e., when viewed along the optical axis J35 of the 0th-order diffracted beam L35).

[0111] As described above, the introduction reflective surface 41 and the light guide 42 (at least a portion of the member surrounding the light guide 42) are preferably provided on a single cut block (in the above example, the second member 252) formed by cutting. This allows the light shielding unit 24 to be manufactured while maintaining the relative positions of the introduction reflective surface 41 and the light guide 42 with high precision.

[0112] The three-dimensional modeling apparatus 1 includes the optical device 12, a laser light source 11, and a scanning unit 13. The laser light source 11 emits a laser beam L31 toward the optical device 12. The scanning unit 13 is the object irradiated with the modulated light beam L33 from the optical device 12, and scans the modulated light beam L33 on the modeling material 91. In the optical device 12, as described above, since the temperature rise of the light shielding unit 24 can be suppressed, the temperature rise of the optical element can be suppressed, and the energy density of the modulated light beam L33 irradiated to the object (i.e., the scanning unit 13) can be appropriately increased. Therefore, in the three-dimensional modeling apparatus 1, the energy density of the modulated light beam L33 irradiated to the modeling material 91 can also be appropriately increased. As a result, the modeling speed of the modeled object in the three-dimensional modeling apparatus 1 can be increased, thereby improving productivity.

[0113] Next, an optical device according to a second embodiment of the present invention will be described. In the optical device according to the second embodiment, a light shielding unit 24a having a structure different from that of the light shielding unit 24 is provided. Figures 1 to 3 In the following description, regarding the configuration of the optical device of the second embodiment, the same components as those of the optical device 12 are denoted by the same reference numerals.

[0114] Figure 11 and Figure 12 2 is a diagram showing the structure of a projection optical system 23a provided with a light shielding unit 24a, which is similar to the above Figure 2 and Figure 3 Corresponding. That is, in Figure 11 In the figure, the direction perpendicular to the paper corresponds to the short axis direction of the modulated light beam L33, and the up and down directions in the figure correspond to the long axis direction of the modulated light beam L33. Figure 12 In the figure, the direction perpendicular to the paper corresponds to the long axis direction of the modulated light beam L33, and the up and down directions in the figure correspond to the short axis direction of the modulated light beam L33.

[0115] The light modulator 22 is, for example, a two-dimensional spatial light modulator and can be, for example, a PLV (Planar Light Valve), an LPLV (Liner Planar Light Valve), or a DMD (Digital Micromirror Device).

[0116] The light shielding unit 24a is positioned between the first lens 231 and the second lens 232 on the optical path of the modulated light beam L33. The light shielding unit 24a allows the 0th-order diffracted light beam L35 from the optical modulator 22 to pass through, while blocking the 1st-order diffracted light beam L36. The light shielding unit 24a is positioned near the focal position of the 0th-order diffracted light beam L35 and blocks the four 1st-order diffracted light beams L36 focused on both sides of the 0th-order diffracted light beam L35 in the major axis direction and on both sides of the minor axis direction. The 1st-order diffracted light beam L36 blocked by the light shielding unit 24a is focused in both the major axis direction and the minor axis direction. In addition, the light shielding unit 24a also blocks the 2nd-order and higher-order non-0th-order diffracted light beams (not shown) from the optical modulator 22.

[0117] Next, refer to Figures 13 to 15 The light shielding unit 24a will be described. Figure 13 It is a perspective view showing the appearance of the light shielding unit 24a. Figure 14 It is a perspective view showing the interior of the light shielding unit 24a. Figure 15 This is a longitudinal sectional view of the light shielding unit 24a in a section passing through the optical axis J35 of the 0th order diffracted beam from the light modulator 22. The light shielding unit 24a has a 0th order diffracted beam opening 240a for allowing the 0th order diffracted beam to pass through. The 0th order diffracted beam opening 240a is similar to the 0th order diffracted beam opening 240 (see FIG. Figure 4 )Similarly, it is located near the focusing position of the 0th order diffraction beam on the optical axis J35 of the 0th order diffraction beam.

[0118] The light shielding unit 24a includes a first member 251a and a second member 252a. Figure 14 , the first member 251a is omitted from the illustration. The first member 251a and the second member 252a are generally rectangular flat plate-shaped members having a generally circular through-hole in the center corresponding to the 0th-order diffracted beam opening 240a. The first member 251a and the second member 252a are arranged in this order on the optical axis J35 of the 0th-order diffracted beam, from the (-X) side (i.e., the direction in which the optical axis J35 of the 0th-order diffracted beam extends, i.e., the near-front side in the optical axis direction), and are fixed to each other, thereby forming the light shielding unit 24a.

[0119] The first member 251a and the second member 252a are light-shielding members that prevent light from the light modulator 22 from passing through. The materials of the first member 251a and the second member 252a are, for example, the same as those of the first member 251, the second member 252, and the third member 253 of the light-shielding unit 24 described above. The second member 252a is, for example, a cut piece formed by cutting. The first member 251a can also be formed by cutting.

[0120] An annular inner protrusion 257a and an annular recess 258a are provided on the principal surface on the (-X) side of the second member 252a (i.e., on the optical modulator 22 side in the direction in which the optical axis J35 of the 0th-order diffracted beam extends). The inner protrusion 257a is provided along the periphery of the through-hole (i.e., the through-hole corresponding to the 0th-order diffracted beam opening 240a) in the central portion of the second member 252a. The inner protrusion 257a protrudes from the principal surface on the (-X) side of the second member 252a toward the (-X) side.

[0121] The annular recess 258a is an annular recess that continuously extends radially outward from the outer peripheral edge of the inner protrusion 257a in the radial direction (hereinafter also referred to as "radial direction") centered on the optical axis J35 of the 0th order diffraction beam. The annular recess 258a is recessed toward the (+X) side compared to the inner protrusion 257a and the portion radially outward of the annular recess 258a. Figure 14 In the example shown, the inner protrusion 257a and the annular recess 258a are arranged in a substantially annular shape concentrically around the optical axis J35 of the 0th-order diffracted light beam when viewed from the front.

[0122] The inner protrusion 257a has a shape in which a generally cylindrical through-hole is provided in the central portion of a generally truncated cone centered on the optical axis J35. The radially outer side surface of the inner protrusion 257a (i.e., the inner circumferential surface serving as the radially inner side surface of the annular recess 258a) is an introduction reflection surface 41a corresponding to the above-mentioned introduction reflection surface 41. The introduction reflection surface 41a is located near the 0th-order diffracted beam opening 240a and surrounds the 0th-order diffracted beam opening 240a. The introduction reflection surface 41a is a generally annular circumferential inclined surface centered on the optical axis J35 (i.e., a surface having a generally truncated cone side shape). The introduction reflection surface 41a faces the (+X) side as it moves radially outward. In other words, the introduction reflection surface 41a moves away from the optical axis J35 as it moves from the front side of the direction extending from the optical axis J35 of the 0th-order diffracted beam (i.e., the optical axis direction) toward the inner side. The introduction reflection surface 41a is, for example, a mirror surface. In addition, the introduction reflection surface 41a may be a scattering reflection surface.

[0123] The annular recess 258a is blocked from the (-X) side by a first member 251a having a through-hole in its center, thereby forming a light guide 42a corresponding to the aforementioned light guide 42. The light guide 42a is a roughly annular space that extends radially outward from the optical axis J35 of the 0th-order diffracted light beam and is surrounded by a light-shielding member. When viewed from the front, the through-hole of the first member 251a is roughly circular with a diameter larger than that of the inner protrusion 257a, exposing the introduction reflective surface 41a on the (-X) side of the light-shielding unit 24a. The introduction port 44a of the light guide 42a is a roughly cylindrical area extending in the X direction between the outer peripheral edge of the through-hole of the first member 251a and the (+X) side of the annular recess 258a. The introduction port 44a is radially opposite the introduction reflective surface 41a.

[0124] The outer peripheral surface of the radially outer side surface of the annular recess 258a is the internal reflection surface 421a corresponding to the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423. The internal reflection surface 421a is a substantially annular inclined surface centered on the optical axis J35. The internal reflection surface 421a has a substantially truncated cone side surface shape that faces the (-X) side as it moves radially outward. The internal reflection surface 421a is radially opposite to the introduction port 44a and the introduction reflection surface 41a. The height of the internal reflection surface 421a in the X direction is substantially the same as the height of the introduction reflection surface 41a in the X direction.

[0125] Internal reflection surface 421a is substantially similar to first internal reflection surface 421 and is a scattering reflection surface provided with fine irregularities. These fine irregularities are, for example, linear irregularities (i.e., thin lines) extending radially along internal reflection surface 421a. In other words, these linear irregularities extend along a surface parallel to both the depth direction (i.e., radial direction) and the depth direction (i.e., X direction) of light guide 42a from internal reflection surface 421a.

[0126] The portion of the main surface on the (+X) side of the first member 251a that faces the annular recess 258a of the second member 252a in the X direction is the light absorbing portion 43a corresponding to the light absorbing portion 43. The light absorbing portion 43a is a plane that is substantially perpendicular to the X direction and has a light absorbing film similar to that of the light absorbing portion 43 provided on its surface. Figure 15 In the illustrated example, the light-absorbing portion 43a is a concave-convex surface with a light-absorbing film applied to its surface. The concave-convex portions provided on the light-absorbing portion 43a are, for example, concentric circles centered on the optical axis J35, and the height of the concave-convex portions (i.e., the height in the X direction) is, for example, approximately several millimeters. Alternatively, the light-absorbing portion 43a may be a substantially smooth surface without concave-convex portions.

[0127] The (-X)-side principal surface of the first member 251a (i.e., the (-X)-side principal surface of the light shielding unit 24a) is a substantially flat surface extending substantially perpendicularly to the X direction and includes a second-order light absorbing portion 255a corresponding to the aforementioned second-order light absorbing portion 255. The second-order light absorbing portion 255a absorbs higher-order diffracted beams, such as the second-order diffracted beam, around the 0th-order diffracted beam opening 240a and the introduction reflection surface 41a.

[0128] In the light shielding unit 24a, the four first-order diffracted beams from the light modulator 22 are incident on the introduction reflective surface 41a. These four first-order diffracted beams are incident on the (+Y) side, (-Y) side, (+Z) side, and (-Z) side of the 0th-order diffracted beam opening 240a on the introduction reflective surface 41a. The introduction reflective surface 41a is positioned near the focal position of the four first-order diffracted beams, along their optical axis J36.

[0129] The introduction reflection surface 41a reflects the four first-order diffracted light beams respectively and guides them to the introduction port 44a of the light guide 42a. Specifically, the first-order diffracted light beam incident on the introduction reflection surface 41a on the (+Y) side of the 0th-order diffracted light beam opening portion 240a is reflected in the (+Y) direction and introduced into the light guide 42a. The first-order diffracted light beam incident on the introduction reflection surface 41a on the (-Y) side of the 0th-order diffracted light beam opening portion 240a is reflected in the (-Y) direction and introduced into the light guide 42a. The first-order diffracted light beam incident on the introduction reflection surface 41a on the (+Z) side of the 0th-order diffracted light beam opening portion 240a is reflected in the (+Z) direction and introduced into the light guide 42a. The first-order diffracted light beam incident on the introduction reflection surface 41a on the (-Z) side of the 0th-order diffracted light beam opening portion 240a is reflected in the (-Z) direction and introduced into the light guide 42a. The reflection direction of each first-order diffracted beam by the introduction reflection surface 41a is a direction deviated from the incident direction of each first-order diffracted beam with respect to the introduction reflection surface 41a, and is a direction away from the optical axis J35 of the 0th-order diffracted beam. In other words, the introduction reflection surface 41a guides each first-order diffracted beam in a direction that is greatly separated from the 0th-order diffracted beam.

[0130] The light guide 42a is a space surrounded by a light shielding member and extends radially parallel to the YZ plane (i.e., a plane perpendicular to the optical axis J35 of the 0th order diffracted light beam). The light guide 42a allows the four first-order lights introduced from the introduction port 44a to be directed along the Figure 15 The light is diffused as indicated by arrows 362 in FIG. 4 and is guided toward the internal reflection surface 421 a located at the end portion opposite to the introduction port 44 a (ie, the terminal portion serving as the outer end portion in the radial direction).

[0131] The four imported first-order lights incident on the internal reflection surface 421a are respectively reflected in the (-X) direction and irradiate the light-absorbing portion 43a, which is the irradiated surface and is provided at the terminal portion of the light guide 42a. The light-absorbing portion 43a absorbs the four imported first-order lights guided by the light guide 42a. In the above-mentioned internal reflection surface 421a, the imported first-order lights are scattered and reflected in the circumferential direction (hereinafter also referred to as "circumferential direction") centered on the optical axis J35 through the linear projections and depressions extending along the above-mentioned radial direction. Therefore, the cross-sectional area (i.e., the irradiation area) of the imported first-order lights irradiated on the light-absorbing portion 43a is expanded. In the internal reflection surface 421a, since the imported first-order lights are hardly scattered in the radial direction, it is possible to suppress the reflected light from the internal reflection surface 421a from returning to the guide inlet 44a and leaking out of the light guide 42a. In addition, as Figure 15 As shown, since the surface of the light absorbing portion 43a is formed as a concave-convex surface, comprising an inclined surface inclined in the X direction relative to the Z direction, light of the introduced primary light incident on the light absorbing portion 43a that is not fully absorbed by the light absorbing portion 43a and is therefore reflected in the direction of the internal reflection surface 421a (i.e., the (+X) direction) can be suppressed. Specifically, by forming the surface of the light absorbing portion 43a as an inclined surface inclined in the X direction, light incident on the inclined surface of the light absorbing portion 43a from the internal reflection surface 421a and reflected therefrom can be directed in the (+Z) or (-Z) direction, thereby entering another position of the light absorbing portion 43a. This allows the light absorbing portion 43a to absorb more light, further reducing the amount of light leaking from the light guide 42a to the outside.

[0132] In the light shielding unit 24a, the four regions where the four first-order diffracted beams enter and are guided as four first-order lights toward the light absorption portion 43a (i.e., the regions on the (+Y) side, (-Y) side, (+Z) side, and (-Z) side of the 0th-order diffracted beam opening 240a) can be considered four light shielding portions 241a. As described above, each light shielding portion 241a includes an introduction reflection surface 41a, a light guide 42a, an internal reflection surface 421a, and a light absorption portion 43a. The introduction reflection surface 41a, light guide 42a, and internal reflection surface 421a of each light shielding portion 241a constitute a portion of the inner circumferential surface of the annular recess 258a, a portion of the outer circumferential surface of the annular recess 258a, and a portion of the outer circumferential surface of the annular recess 258a.

[0133] Figure 16 2 is an enlarged cross-sectional view showing one light shielding portion 241a. Figure 16 In FIG, the first-order diffracted light beam L36 incident on the introduction reflection surface 41a is depicted by a solid line, and the optical axis J36 of the first-order diffracted light beam L36 is depicted by a dashed line. Figure 16 In FIG. 4 , the introduced first-order light L37 when no scattering occurs on the internal reflection surface 421 a is depicted by a solid line, and the optical axis J37 of the introduced first-order light L37 is depicted by a dashed line.

[0134] As described above, the introduction reflection surface 41a is arranged near the focus position 360 of the first-order diffracted light beam L36. Figure 16 In the example shown, the introduction reflection surface 41a is arranged on the optical axis J36 of the first-order diffracted light beam L36, on the inner side of the focal position 360 of the first-order diffracted light beam L36 (that is, along the optical axis J36 of the first-order diffracted light beam L36, on the side opposite to the optical modulator 22 with the focal position 360 therebetween). In other words, the focal position 360 of the first-order diffracted light beam L36 is located between the introduction reflection surface 41a and the optical modulator 22 (see FIG. Figure 11 and Figure 12 )between.

[0135] After passing through the aforementioned focal position 360, the first-order diffracted light beam L36 from the optical modulator 22 toward the introduction reflection surface 41a expands its area in a cross section perpendicular to the optical axis J36 (i.e., diffuses) as it enters the introduction reflection surface 41a. The introduced first-order light L37, which is reflected by the introduction reflection surface 41a and introduced into the light guide 42a, similarly diffuses while traveling within the light guide 42a toward the internal reflection surface 421a. After being reflected by the internal reflection surface 421a, the introduced first-order light L37 is also similarly diffused while being guided toward the light absorption portion 43a. Therefore, the area illuminated by the introduced first-order light L37 on the light absorption portion 43a increases, and the energy density of the introduced first-order light L37 decreases. As a result, it is possible to suppress a temperature rise in the light absorption portion 43a (particularly a local temperature rise in the area illuminated by the introduced first-order light L37).

[0136] like Figure 15 As shown, a cooling channel 256a is provided within the first member 251a on the (-X) side of the light absorbing portion 43a. The cooling channel 256a is positioned near the light absorbing portion 43a (i.e., the (+X)-side main surface of the first member 251a). The cooling channel 256a has, for example, a rectangular frame shape that substantially overlaps the annular recess 258a when viewed from the front. A coolant, such as water, flows within the cooling channel 256a. This further suppresses temperature increases in the light absorbing portion 43a.

[0137] In addition, a cooling flow path 259a is provided inside the second component 252a on the (+X) side of the light guide 42a. The cooling flow path 259a is arranged near the light guide 42a. The cooling flow path 259a is, for example, in the shape of a rectangular frame that roughly overlaps with the annular recess 258a when viewed from the front. A coolant such as water flows inside the cooling flow path 259a, similar to the cooling flow path 256a. Thus, even if a temperature rise occurs in the light guide 42a due to scattering of the introduced first-order light, the temperature rise can be effectively suppressed. In the light shielding unit 24a, a temperature sensor can also be arranged near the cooling flow paths 256a and 259a to measure the temperature of the light absorbing portion 43a and the light guide 42a. Thus, an abnormal temperature rise in the light shielding unit 24a can be easily detected.

[0138] As described above, in the optical device of the second embodiment, similar to the first embodiment, the projection optical system 23a includes a light shielding unit 24a that allows the 0th-order diffracted beam L35 from the light modulator 22 to pass through while shielding the 1st-order diffracted beam L36. The light shielding unit 24a includes a 0th-order diffracted beam opening 240a, an introduction reflection surface 41a, a light guide 42a, and a light absorption unit 43a. The 0th-order diffracted beam opening 240a is located near the focal position of the 0th-order diffracted beam L35 on the optical axis J35 of the 0th-order diffracted beam L35 and allows the 0th-order diffracted beam L35 to pass through. The introduction reflection surface 41a is located near the focal position 360 of the 1st-order diffracted beam L36 on the optical axis J36 of the 1st-order diffracted beam L36 and is also located near the 0th-order diffracted beam opening 240a. The introduction reflective surface 41a reflects the first-order diffracted light beam L36 in a direction deviating from the incident direction of the first-order diffracted light beam L36 and away from the optical axis J35 of the zero-order diffracted light beam L35. The light guide 42a includes an introduction port 44a for incident light from the introduction reflective surface and guides the light introduced from the introduction port 44a (i.e., the first-order light). The light guide 42a is surrounded by a light shielding member. The light absorbing portion 43a absorbs the light diffused and guided by the light guide 42a.

[0139] In the light shielding unit 24a, light leakage from the light shielding unit 24a to the outside can be suppressed, and the temperature rise of the light shielding unit 24a can be suppressed, similarly to the light shielding unit 24 described above. In addition, since a relatively inexpensive and long-life light absorption film can be used, the manufacturing cost of the light shielding unit 24a can be reduced and the life of the light shielding unit 24a can be extended.

[0140] As described above, the introduction reflective surface 41a is preferably a mirror surface. Furthermore, the light guide 42a preferably includes an internal scattering reflective surface (i.e., internal reflective surface 421a) that scatters and reflects the light from the introduction reflective surface 41a to guide it. This prevents scattering of the first-order diffracted light beam L36 on the introduction reflective surface 41a, allowing substantially all of the first-order diffracted light beam L36 incident on the introduction reflective surface 41a to be guided into the interior of the light guide 42a. Furthermore, diffusion of the introduced first-order light within the light guide 42a is promoted.

[0141] The internal reflection surface 421a preferably has linear fine irregularities extending parallel to both the depth direction (i.e., radial direction) and the depth direction (i.e., X direction) of the light guide 42a. This prevents the introduced primary light incident on the internal reflection surface 421a from returning in the direction of incidence (i.e., radially inward) and scatters the introduced primary light. Consequently, the diffusion of the introduced primary light within the light guide 42a can be appropriately promoted.

[0142] As described above, the introduction reflective surface 41a is preferably positioned on the optical axis J36 of the first-order diffracted beam L36, further inward than the focal position 360 of the first-order diffracted beam L36. This reduces the energy density of the first-order diffracted beam L36 on the introduction reflective surface 41a. Consequently, temperature increases and damage to the introduction reflective surface 41a can be suppressed. Furthermore, the introduction of the first-order light introduced from the introduction reflective surface 41a into the light guide 42a can be reliably prevented from focusing on a reflective surface within the light guide 42a (i.e., the internal reflective surface 421a). Consequently, temperature increases and damage to the internal reflective surface 421a can be suppressed.

[0143] In addition, the introduction reflection surface 41a can also be arranged on the optical axis J36 of the first-order diffracted light beam L36, closer to the front side than the focusing position 360 of the first-order diffracted light beam L36. In this case, as described above, the energy density of the first-order diffracted light beam L36 on the introduction reflection surface 41a can be reduced. As a result, the temperature rise, damage, etc. of the introduction reflection surface 41a can be suppressed. In addition, in this case, it is preferred that the first-order diffracted light beam L36 is focused between the reflection surface (i.e., the internal reflection surface 421a) on which the introduced first-order light from the introduction reflection surface 41a directly enters in the light guide 42a and the introduction reflection surface 41a. Thereby, the energy density of the first-order diffracted light beam L36 on the internal reflection surface 421a can be reduced. As a result, the temperature rise, damage, etc. of the internal reflection surface 421a can be suppressed.

[0144] The introduction reflection surface 41a may also be arranged at the focus position 360 of the first-order diffracted beam L36. In this case, the area of ​​the introduction reflection surface 41a can be reduced. In addition, since the gap between the first-order diffracted beam L36 and the zero-order diffracted beam L35 is increased, the first-order diffracted beam L36 can be easily separated from the zero-order diffracted beam L35.

[0145] As described above, the light absorbing portion 43a preferably has a concave-convex surface with a light absorbing film applied to the surface. This increases the area of ​​the light absorbing portion 43a illuminated by the introduced primary light, thereby reducing the energy density of the introduced primary light that irradiates the light absorbing portion 43a. Consequently, the temperature rise of the light shielding unit 24a can be further suppressed.

[0146] As described above, the light shielding unit 24a preferably further includes a cooling flow path 256a disposed near the light absorbing portion 43a and through which a coolant flows. This allows the light absorbing portion 43a to be cooled, further suppressing temperature increases in the light shielding unit 24a. Furthermore, a cooling flow path 259a is preferably also disposed near the light guide 42a, through which a coolant flows. This also allows the light guide 42a to be cooled, further suppressing temperature increases in the light shielding unit 24a.

[0147] As described above, in the light shielding unit 24a, it is preferable to provide a second-order light absorbing portion 255a for absorbing the second-order diffracted light beam from the light modulator 22 on the outer surface extending in a direction perpendicular to the optical axis J35 of the 0th-order diffracted light beam L35 around the 0th-order diffracted light beam opening 240a and the introduction reflection surface 41a. This prevents the light shielding unit 24a from being enlarged, and allows shielding of non-0th-order diffracted light beams of the second and higher orders.

[0148] As described above, the light guide 42a preferably extends parallel to a plane perpendicular to the optical axis J35 of the 0th-order diffracted light beam L35. This allows the light shielding unit 24a to be miniaturized in the direction in which the optical axis J35 extends.

[0149] As described above, the introduction reflective surface 41a and the light guide 42a (at least a portion of the member surrounding the light guide 42a) are preferably provided on a single cut block (in the above example, the second member 252a) formed by cutting. This allows the light shielding unit 24a to be manufactured while maintaining the relative position of the introduction reflective surface 41a and the light guide 42a with high precision.

[0150] As described above, the reflective introduction surface is preferably a portion of a circumferentially inclined surface that surrounds the 0th-order diffracted beam opening 240a and that moves away from the optical axis J35 of the 0th-order diffracted beam L35 as it moves from the front side toward the back in the optical axis direction of the 0th-order diffracted beam L35. Furthermore, the light guide 42a is preferably a portion of an annular space that radially extends outward from this circumferentially inclined surface. This allows for easy handling of a large number of first-order diffracted beams L36 shielded by the light shielding unit 24a without changing the structure of the light shielding unit 24a.

[0151] In the three-dimensional modeling apparatus 1 (see Figure 1 ), as described above, the energy density of the modulated light beam L33 irradiated on the molding material 91 can also be appropriately increased. As a result, the molding speed of the molded object in the three-dimensional molding apparatus 1 can be increased, thereby improving productivity.

[0152] Next, an optical device according to a third embodiment of the present invention will be described. In the optical device according to the third embodiment, a light shielding unit 24b having a structure different from the light shielding units 24 and 24a described above is provided. In addition, in this optical device, a two-dimensional spatial light modulator (e.g., LPLV) is used as the light modulator 22, and by changing the illumination optical system 21 and the projection optical system 23 (see Figure 1 ) optical element, the 0th order diffraction beam, the 1st order diffraction beam and the 2nd order or higher non-0th order diffraction beam incident on the shading unit 24b are in a focused state in only one direction between the long axis direction and the short axis direction.

[0153] Figure 17 It is a perspective view showing the appearance of the light shielding unit 24b. Figure 18 2 is a perspective view showing the interior of the light shielding unit 24b. Figure 18 In the figure, the upper portion of the light shielding unit 24b is omitted. Figure 19 2 is a transverse cross-sectional view of the light shielding unit 24b.

[0154] The light shielding unit 24b is arranged between the light modulator 22 (refer to Figure 1 ) has a 0th order diffraction beam opening 240b through which the 0th order diffraction beam passes and blocks the 1st order diffraction beam. The 0th order diffraction beam and the 1st order diffraction beam incident on the light shielding unit 24b are focused only in the short axis direction and are not focused in the long axis direction (i.e., Figure 17The 0th-order diffracted beam and the 1st-order diffracted beam are not focused in the vertical direction (in the vertical direction). In other words, the 0th-order diffracted beam and the 1st-order diffracted beam are planar beams that expand in the long-axis direction. The 0th-order diffracted beam opening 240b is slit-shaped and extends in the long-axis direction (i.e., the Z direction). The light shielding unit 24b shields the two 1st-order diffracted beams that are focused on both sides of the 0th-order diffracted beam in the short-axis direction (i.e., the (+Y) side and the (-Y) side).

[0155] The light shielding unit 24b includes a first member 251b and a second member 252b. The first and second members 251b and 252b are generally rectangular parallelepiped members with a slit (i.e., a vertically elongated through-hole or slot) at their centers corresponding to the 0th-order diffracted beam opening 240b. The first and second members 251b and 252b are arranged in this order on the optical axis J35 of the 0th-order diffracted beam, from the (-X) side (i.e., the direction in which the optical axis J35 of the 0th-order diffracted beam extends, i.e., the near-front side in the optical axis direction), and are fixed to each other, thereby forming the light shielding unit 24b.

[0156] The first member 251b and the second member 252b are light-shielding members that prevent light from the optical modulator 22 from passing through. The materials of the first member 251b and the second member 252b are, for example, the same as those of the first member 251, the second member 252, and the third member 253 of the light-shielding unit 24 described above. The first member 251b is formed by connecting two first blocks 261b arranged adjacent to each other in the Y direction. As described later, each first block 261b is a light-shielding portion 241b having an inlet reflective surface and a light guide path 42b. The two first blocks 261b are, for example, each cut block formed by cutting. Alternatively, each first block 261b may be formed by a plurality of cut blocks fixed to each other.

[0157] In the first member 251b, the slit-like space extending in the Z direction between the two first blocks 261b separated in the Y direction corresponds to the zero-order diffracted beam opening 240b. Furthermore, each first block 261b is provided with a light guide 42b that extends away from the zero-order diffracted beam opening 240b as it moves toward the (+X) direction (i.e., away from the optical axis J35 of the zero-order diffracted beam). The light guide 42b is a slit-like space extending in the Z direction in a direction oblique to the optical axis J35 of the zero-order diffracted beam.

[0158] The side surfaces of the light guide 42b are a pair of parallel reflecting surfaces 421b. Each reflecting surface 421b is, for example, a mirror surface. The first-order diffracted light beam from the light modulator 22 is as follows: Figure 19As indicated by arrow 363, the light is directed toward the (-X) end of the (+X)-side reflective surface 421b of the pair of reflective surfaces 421b (i.e., the end closer to the optical axis J35 of the 0th-order diffracted light beam), where it is reflected by this end and guided into the light guide 42b. In other words, this end serves as the introduction reflective surface 41b that guides the 1st-order diffracted light beam into the light guide 42b. Furthermore, the space near the introduction reflective surface 41b of the light guide 42b serves as the introduction port 44b.

[0159] The first-order light introduced from the introduction reflective surface 41b into the light guide 42b is repeatedly reflected between the pair of reflective surfaces 421b along arrow 363. While traveling back and forth between the pair of reflective surfaces 421b, it is guided within the light guide 42b in the (+X) direction and away from the optical axis J35 of the 0th-order diffracted light beam. Specifically, the portion of the pair of reflective surfaces 421b other than the introduction reflective surface 41b (i.e., the (-X)-side end of the (+X)-side reflective surface 421b) serves as an internal reflective surface within the light guide 42b.

[0160] The introduced primary light is guided toward the terminal portion 425b (i.e., the (+X)-side end) of the light guide 42b while being diffused, similarly to the above description. In the terminal portion 425b of the light guide 42b, the distance between the pair of reflective surfaces 421b, when viewed from above, gradually increases as it approaches the (+X) side. In the terminal portion 425b of the light guide 42b, the introduced primary light is repeatedly reflected between the pair of reflective surfaces 421b, thereby further diffusing. Having passed through the terminal portion 425b of the light guide 42b, the introduced primary light is absorbed by the light absorbing portion 43b, which is provided on the (-X)-side principal surface of the second member 252b in an area opposite the terminal portion 425b in the X direction. The diffusion of the introduced primary light as described above increases the area illuminated by the introduced primary light on the light absorbing portion 43b, reducing the energy density of the introduced primary light. As a result, a temperature increase in the light absorbing portion 43 b (particularly, a local temperature increase in the region irradiated with the introduced primary light) can be suppressed.

[0161] In the light guide 42b, at the terminal portion 425b, the pair of reflective surfaces 421b may be provided with fine irregularities to serve as scattering reflective surfaces. This facilitates the diffusion of the primary light introduced into the terminal portion 425b, further suppressing the temperature rise of the light absorbing portion 43b. For example, these fine irregularities may be linear irregularities extending along each reflective surface 421b in the X direction (i.e., extending along a surface parallel to both the depth direction up to and from each reflective surface 421b in the terminal portion 425b of the light guide 42b). This prevents light reflected from the terminal portion 425b of each reflective surface 421b from returning to the inlet 44b and escaping from the light guide 42b.

[0162] The light-absorbing portion 43b is a concave-convex surface with a light-absorbing film applied to its surface. The concave-convex portion of the light-absorbing portion 43b is, for example, a groove-shaped surface extending approximately parallel to the Z direction. The height of the concave-convex portion (i.e., the height in the X direction) is, for example, several millimeters. The concave-convex surface of the light-absorbing portion 43b increases the area of ​​primary light irradiated onto the light-absorbing portion 43b, thereby reducing the energy density. As a result, the temperature rise of the light-absorbing portion 43b can be further suppressed.

[0163] A cooling channel 256b is provided within the second member 252b on the (+X) side of the light absorbing portion 43b. The cooling channel 256b is positioned near the light absorbing portion 43b. The cooling channel 256b extends substantially linearly in the Z direction, for example, and substantially overlaps with the light absorbing portion 43b when viewed from the front. This cools the light absorbing portion 43b, further suppressing temperature increases in the light shielding unit 24b.

[0164] Inside the first component 251b, a cooling flow path 259b is provided on the opposite side of the 0th-order diffraction beam opening portion 240b across the light guide 42b. The cooling flow path 259b is arranged near the light guide 42b. The cooling flow path 259b extends approximately linearly in the Z direction, for example, and approximately overlaps with the light guide 42b when viewed from the front and the side. As a result, the light guide 42b is cooled, thereby further suppressing the temperature rise of the light shielding unit 24b. In the light shielding unit 24b, a temperature sensor can also be arranged near the cooling flow paths 256b and 259b to measure the temperature of the light absorbing portion 43b and the light guide 42b. As a result, abnormal temperature rise of the light shielding unit 24b can be easily detected.

[0165] In the light shielding unit 24b, the distance in the Y direction between the two first blocks 261b of the first member 251b can also be changed. This distance can be changed, for example, by changing the length in the Y direction of the connecting member connecting the two first blocks 261b. This allows the Y-direction distance between the 0th-order diffracted beam opening 240b and the introduction and reflection surface 41b of each first block 261b to be changed. This makes it possible to easily cope with changes in the Y-direction distance between the optical axis J35 of the 0th-order diffracted beam and the optical axis J36 of the 1st-order diffracted beam caused by, for example, changes in the optical modulator 22.

[0166] In the light shielding unit 24b, the principal surface on the (-X) side of the first member 251b (i.e., the principal surface on the (-X) side of the light shielding unit 24b) is a substantially flat surface extending substantially perpendicularly to the X direction, and includes a second-order light absorbing portion 255b corresponding to the aforementioned second-order light absorbing portion 255. The second-order light absorbing portion 255b absorbs higher-order diffracted beams, such as the second-order diffracted beam, around the 0th-order diffracted beam opening 240b and the introduction reflection surface 41b.

[0167] As described above, in the optical device of the third embodiment, similarly to the first embodiment, the light shielding unit 24b includes a 0th-order diffracted beam opening 240b, an introduction reflection surface 41b, a light guide 42b, and a light absorption portion 43b. The 0th-order diffracted beam opening 240b is located near the focal position of the 0th-order diffracted beam on the optical axis J36 of the 0th-order diffracted beam, allowing the 0th-order diffracted beam to pass through. The introduction reflection surface 41b is located near the focal position of the 1st-order diffracted beam on the optical axis J36 of the 1st-order diffracted beam and is located near the 0th-order diffracted beam opening 240b. The introduction reflection surface 41b reflects the 1st-order diffracted beam in a direction offset from the incident direction of the 1st-order diffracted beam and away from the optical axis J35 of the 0th-order diffracted beam. The light guide 42b includes an introduction port 44b for incident light from the introduction reflection surface 41b, and guides the light introduced from the introduction port 44b (i.e., the introduced 1st-order light). The light guide path 42b is surrounded by a light shielding member. The light absorbing portion 43b absorbs the light diffused and guided by the light guide path 42b.

[0168] In the light shielding unit 24b, similarly to the light shielding unit 24 described above, light leakage from the light shielding unit 24b to the outside can be suppressed, and a temperature rise in the light shielding unit 24b can be suppressed. In addition, since a relatively inexpensive and long-life light absorption film can be used, the manufacturing cost of the light shielding unit 24b can be reduced and the life of the light shielding unit 24b can be extended.

[0169] As described above, the introduction reflective surface 41b is preferably a mirrored surface. Furthermore, the light guide 42b preferably includes an internal scattering reflective surface (in the above example, the reflective surface 421b at the terminal portion 425b of the light guide 42b) that scatters and reflects the light from the introduction reflective surface 41b to guide it. This prevents scattering of the first-order diffracted light beam on the introduction reflective surface 41b, allowing substantially all of the first-order diffracted light beam incident on the introduction reflective surface 41b to be guided into the interior of the light guide 42b. Furthermore, the diffusion of the introduced first-order light within the light guide 42b is promoted.

[0170] The scattering reflective surface (i.e., the reflective surface 421b at the terminal end 425b of the light guide 42b) preferably has linear micro-concavities and convexities extending parallel to both the depth direction up to and from the scattering reflective surface within the light guide 42b. This prevents the introduced primary light reflected by the scattering reflective surface from returning in the direction of incidence and scatters the introduced primary light. As a result, the diffusion of the introduced primary light within the light guide 42b can be appropriately promoted. Furthermore, in the light shielding unit 24b, portions of the pair of reflective surfaces 421b other than the terminal end 425b and / or the introduction reflective surface 41b may also be scattering reflective surfaces.

[0171] In light shielding unit 24b, similar to light shielding unit 24a, introduction reflective surface 41b can be positioned further inward than the focal position of the first-order diffracted beam on optical axis J36 of the first-order diffracted beam. This reduces the energy density of the first-order diffracted beam on introduction reflective surface 41b. Consequently, temperature increases and damage to introduction reflective surface 41b can be suppressed. Furthermore, the introduction of first-order light from introduction reflective surface 41b into light guide 42b can be reliably prevented from focusing on reflective surface 421b within light guide 42b. Consequently, temperature increases and damage to reflective surface 421b can be suppressed.

[0172] In addition, in the shading unit 24b, substantially similarly to the shading unit 24, the introduction reflection surface 41b can also be arranged on the optical axis J36 of the first-order diffracted light beam, closer to the front side than the focusing position of the first-order diffracted light beam. In this case, as described above, the energy density of the first-order diffracted light beam on the introduction reflection surface 41b can be reduced. As a result, the temperature rise, damage, etc. of the introduction reflection surface 41b can be suppressed. In addition, in this case, preferably, the first-order diffracted light beam is focused between the reflection surface on which the introduced first-order light from the introduction reflection surface 41b directly enters in the light guide 42b (i.e., the reflection surface 421b opposite to the introduction reflection surface 41b) and the introduction reflection surface 41b. As a result, the energy density of the first-order diffracted light beam on the reflection surface 421b opposite to the introduction reflection surface 41b can be reduced. As a result, the temperature rise, damage, etc. of the reflection surface 421b can be suppressed.

[0173] Alternatively, the introduction reflection surface 41b may be arranged at the focus position of the first-order diffracted beam. In this case, since the gap between the first-order diffracted beam and the zero-order diffracted beam in the Y direction becomes larger, the first-order diffracted beam and the zero-order diffracted beam can be easily separated.

[0174] As described above, the light absorbing portion 43b preferably has a concave-convex surface with a light absorbing film formed on the surface. This increases the area of ​​the light absorbing portion 43b illuminated by the introduced primary light, thereby reducing the energy density of the introduced primary light that irradiates the light absorbing portion 43b. Consequently, the temperature rise of the light shielding unit 24b can be further suppressed.

[0175] As described above, the light shielding unit 24b preferably further includes a cooling flow path 256b disposed near the light absorbing portion 43b and through which a coolant flows. This allows the light absorbing portion 43b to be cooled, further suppressing temperature increases in the light shielding unit 24b. Furthermore, a cooling flow path 259b is preferably also disposed near the light guide 42b, through which a coolant flows. This also allows the light guide 42b to be cooled, further suppressing temperature increases in the light shielding unit 24b.

[0176] In the light shielding unit 24b, similarly to the light shielding unit 24, a second-order light absorbing portion 255b is preferably provided on the outer surface extending in a direction perpendicular to the optical axis J35 of the 0th-order diffracted beam around the 0th-order diffracted beam opening 240b and the introduction reflection surface 41b. The second-order light absorbing portion 255b absorbs the second-order diffracted beam from the light modulator 22. This prevents the light shielding unit 24b from becoming larger in size and allows for shielding of the second-order and higher-order non-0th-order diffracted beams.

[0177] As described above, the set of the introduction reflective surface 41b and the light guide 42b (at least a portion of the member surrounding the light guide 42b) is preferably provided on a single cut piece (in the above example, the first piece 261b of the first member 251b) formed by cutting. This allows the light shielding unit 24b to be manufactured while maintaining the relative position of the introduction reflective surface 41b and the light guide 42b with high precision.

[0178] As described above, the shading unit 24b blocks multiple (two in the above example) first-order diffracted light beams from the optical modulator 22, and has multiple shading portions 241b corresponding to the multiple first-order diffracted light beams. Each shading portion 241b has an introduction reflection surface 41b and a light guide path 42b. Preferably, the relative positions of the multiple shading portions 241b (in the above example, the two first blocks 261b) with respect to the 0th-order diffracted light beam opening portion 240b are variable. Therefore, since the Y-direction distance between the 0th-order diffracted light beam opening portion 240b and the introduction reflection surface 41b of each first block 261b can be changed, it is possible to easily cope with changes in the Y-direction distance between the optical axis J35 of the 0th-order diffracted light beam and the optical axis J36 of the 1st-order diffracted light beam caused by changes in the optical modulator 22, etc.

[0179] In the three-dimensional modeling apparatus 1 (see Figure 1 ), as described above, the energy density of the modulated light beam L33 irradiated on the molding material 91 can also be appropriately increased. As a result, the molding speed of the molded object in the three-dimensional molding apparatus 1 can be increased, thereby improving productivity.

[0180] Various modifications can be made to the light shielding units 24, 24a, and 24b, the optical device 12, and the three-dimensional modeling device 1 described above.

[0181] For example, the shape and structure of the light absorbing portion 43 of the light shielding unit 24 can be modified in various ways. For example, the light absorbing portion 43 can have a concave-convex surface, or a smooth surface can be provided on the light absorbing portion 43 instead of the concave-convex surface. The same applies to the light absorbing portion 43a of the light shielding unit 24a and the light absorbing portion 43b of the light shielding unit 24b.

[0182] The shape and structure of the secondary light absorbing portion 255 of the light shielding unit 24 can be modified in various ways. Alternatively, the secondary light absorbing portion 255 can be omitted from the light shielding unit 24. The same applies to the secondary light absorbing portion 255a of the light shielding unit 24a and the secondary light absorbing portion 255b of the light shielding unit 24b.

[0183] In the light shielding unit 24, the introduction reflection surface 41, the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423 can be mirror surfaces or diffuse reflection surfaces. The same applies to the introduction reflection surface 41a and the internal reflection surface 421a of the light shielding unit 24a, and the introduction reflection surface 41b and the reflection surface 421b of the light shielding unit 24b.

[0184] In the light shielding unit 24, when the fine irregularities 424 are provided on the first internal reflection surface 421, the second internal reflection surface 422, and the third internal reflection surface 423, the fine irregularities 424 do not necessarily need to be linear irregularities extending in the above-mentioned directions. For example, fine irregularities 424 may be pear-skin-shaped irregularities, and various modifications are possible. The same applies to the internal reflection surface 421a of the light shielding unit 24a and the reflection surface 421b of the light shielding unit 24b.

[0185] The arrangement of the cooling channels 256 in the light shielding unit 24 is not limited to the above example and can be modified in various ways. Furthermore, the cooling channels 256 can be omitted in the light shielding unit 24. This also applies to the cooling channels 256a and 259a of the light shielding unit 24a and the cooling channels 256b and 259b of the light shielding unit 24b.

[0186] In the light shielding unit 24, the light guide 42 does not necessarily need to extend parallel to the plane perpendicular to the optical axis J35 of the 0th-order diffracted light beam L35, but may extend in a direction inclined relative to the plane.

[0187] In the light shielding unit 24a, the shapes of the introduction reflection surface 41a, the light guide path 42a, the internal reflection surface 421a and the light absorption portion 43a when viewed from the front are not necessarily circular, and various changes can be made as long as they are substantially rectangular or other annular shapes.

[0188] The light shielding unit 24b does not necessarily need to be used to shield a planar light beam focused in only one of the major axis direction or the minor axis direction, and can also be used to shield a light beam focused in both the major axis direction and the minor axis direction. In addition, the light shielding units 24 and 24a can also be used to shield a planar light beam.

[0189] In the light shielding unit 24, similarly to the light shielding unit 24b, the relative positions of the plurality of light shielding portions 241 with respect to the zero-order diffracted beam opening 240 can also be made variable. This makes it possible to easily cope with changes in the distance between the optical axis J35 of the zero-order diffracted beam L35 and the optical axis J36 of the first-order diffracted beam L36 caused by, for example, changes in the optical modulator 22, as described above. The same applies to the light shielding unit 24a.

[0190] The members constituting the light shielding units 24 , 24 a , and 24 b do not necessarily need to be formed by cutting, and may be formed by various other methods.

[0191] The light modulator 22 of the optical device 12 is not limited to the above-mentioned GLV, PLV, LPLV or DMD, and can be variously modified. In addition, the shape of the laser light shaped by the illumination optical system 21 is not limited to the above-mentioned example, and can be variously modified.

[0192] The scanning unit 13 of the three-dimensional modeling apparatus 1 does not necessarily need to include the galvano mirror 132; as described above, it may also include another structure such as a polygon laser scanner. Alternatively, the scanning unit 13 is not limited to changing the direction of travel of the modulated light beam L33 from the projection optical system 23. For example, it may be a moving mechanism such as a linear motor that moves the modeling unit 141 holding the modeling material 91 in the horizontal direction while the irradiation position of the modulated light beam L33 is fixed.

[0193] The optical device 12 does not necessarily need to be provided in the three-dimensional modeling apparatus 1 , and may be used in a laser processing machine such as a laser marking apparatus, for example.

[0194] The configurations in the above-described embodiment and various modifications may be appropriately combined as long as they do not contradict each other.

[0195] Although the present invention has been described and illustrated in detail, the above description is illustrative rather than restrictive. Therefore, many modifications and variations are possible without departing from the scope of the present invention.

[0196] Description of reference numerals:

[0197] 1. Three-dimensional modeling device

[0198] 11Laser light source

[0199] 12 Optical devices

[0200] 13 Scanning Department

[0201] 21 Illumination optical system

[0202] 22 optical modulators

[0203] 23.23a Projection optical system

[0204] 24, 24a, 24b shading unit

[0205] 41, 41a, 41b are introduced into the reflective surface

[0206] 42, 42a, 42b light guide path

[0207] 43, 43a, 43b light absorbing part

[0208] 44, 44a, 44b inlet

[0209] 91 modeling materials

[0210] 240, 240a, 240b 0th order diffraction beam openings

[0211] 241, 241a, 241b light shielding parts

[0212] 251, 251a, 251b first component

[0213] 252, 252a, 252b second component

[0214] 253 Third Component

[0215] 255, 255a, 255b 2nd level light absorption unit

[0216] 256, 256a, 256b, 259a, 259b cooling flow path

[0217] 261b first block

[0218] 360 focus position

[0219] 421 first internal reflection surface

[0220] 421a internal reflective surface

[0221] 421b reflective surface

[0222] 422 second internal reflection surface

[0223] 423 Third internal reflection surface

[0224] 424 fine concave and convex

[0225] J35, J36, J37 optical axis

[0226] L31 Laser

[0227] L32 parallel beam

[0228] L33 modulated beam

[0229] L350-order diffracted beam

[0230] L361 diffracted beam

[0231] L37 imports level 1 light

Claims

1. An optical device for irradiating a modulated light onto an object, wherein: The optical device comprises: The illumination optical system shapes the laser light emitted from the laser light source into a specified shape; an optical modulator for modulating the laser light shaped by the illumination optical system into a modulated light beam; and A projection optical system guides the modulated light beam toward an object, The projection optical system includes a light shielding unit that allows the 0th-order diffracted light beam from the light modulator to pass through and shields the 1st-order diffracted light beam. The shading unit comprises: a 0th-order diffraction beam opening, located near a focus position of the 0th-order diffraction beam on the optical axis of the 0th-order diffraction beam, allowing the 0th-order diffraction beam to pass through; an introduction reflecting surface, located near the focus position of the first-order diffracted beam on the optical axis of the first-order diffracted beam and near the opening of the zero-order diffracted beam, reflecting the first-order diffracted beam in a direction deviating from the incident direction of the first-order diffracted beam and away from the optical axis of the zero-order diffracted beam; a light guide having an introduction port for incident light from the introduction reflection surface, and guiding the light introduced from the introduction port, wherein the light guide is surrounded by a light shielding member; and The light absorbing portion absorbs the light diffused and guided by the light guiding path.

2. The optical device according to claim 1, wherein The introduction reflection surface is a mirror surface, The light guide path includes a scattering reflection surface inside thereof for scattering and reflecting the light from the introduction reflection surface to guide the light.

3. The optical device according to claim 2, wherein The scattering and reflecting surface has linear fine irregularities extending along a surface parallel to both a depth direction to the scattering and reflecting surface and a depth direction from the scattering and reflecting surface in the light guide.

4. The optical device according to claim 1, wherein The introduction reflection surface is arranged on the optical axis of the first-order diffracted light beam at a position closer to the front side than the focus position of the first-order diffracted light beam. The first-order diffraction beam is focused between the reflective surface on which the light from the introduction reflective surface in the light guide path is directly incident and the introduction reflective surface.

5. The optical device according to claim 1, wherein The light absorbing portion has a concavo-convex surface with a light absorbing film provided on the surface.

6. The optical device according to claim 1, wherein The light shielding unit further includes a cooling flow path that is arranged near the light absorbing portion and through which a coolant flows.

7. The optical device according to claim 6, wherein A cooling flow path through which a coolant flows is also arranged near the light guide path.

8. The optical device according to claim 1, wherein In the shading unit, around the 0th order diffraction beam opening and the introduction reflection surface, a 2nd order light absorption portion for absorbing the 2nd order diffraction beam from the light modulator is provided on the outer surface extending in a direction perpendicular to the optical axis of the 0th order diffraction beam.

9. The optical device according to any one of claims 1 to 8, wherein: The light guide extends parallel to a plane perpendicular to the optical axis of the 0th-order diffracted light beam.

10. The optical device according to claim 9, wherein The light guiding path bends and extends around the 0th-order diffraction beam opening to surround the 0th-order diffraction beam opening.

11. The optical device according to any one of claims 1 to 8, wherein: The introduction reflection surface is a portion of a circumferential inclined surface surrounding the opening of the 0th order diffracted beam and moving away from the optical axis of the 0th order diffracted beam as it moves from the front side toward the back side in the optical axis direction of the 0th order diffracted beam. The light guide is a portion of an annular space that radially expands outward from the circumferential inclined surface.

12. The optical device according to any one of claims 1 to 8, wherein: The 0th-order diffracted beam and the 1st-order diffracted beam are planar beams that expand in the vertical direction. The light guide has a pair of mutually parallel reflecting surfaces extending in a direction inclined with respect to the optical axis of the 0th order diffracted light beam and in a vertical direction. The introduction reflection surface is an end portion of one of the pair of reflection surfaces, which is close to the 0th order diffracted light beam. The light from the introduction reflection surface is guided within the light guide path while reciprocating between the pair of reflection surfaces.

13. The optical device according to any one of claims 1 to 8, wherein: The introduction reflection surface and the light guide path are arranged on a cutting block formed by cutting.

14. The optical device according to claim 13, wherein The shading unit blocks a plurality of first-order diffracted light beams from the light modulator, The shading unit has a plurality of shading portions corresponding to the plurality of first-order diffracted light beams, respectively. Each light shielding portion has the introduction reflection surface and the light guide path, The relative positions of the plurality of light shielding portions with respect to the 0th-order diffraction beam opening are variable.

15. A three-dimensional modeling device, wherein: have: The optical device according to any one of claims 1 to 14; a laser light source for emitting the laser light toward the optical device; and A scanning unit is configured to scan the modulated light beam on the object irradiated with the modulated light beam from the optical device.

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