Optical device and three-dimensional molding device

Abstract

To simplify the structure of an optical device.SOLUTION: A second optical system 23 of an optical device 12 includes a short axis side light-shielding part 236, a third lens 233, a long axis side light-shielding part 235, a fourth lens 234, and a scanning mechanism 237. The long axis side light-shielding part 235 is arranged at the focal position on the long axis side of a modulation beam L33 by the third lens 233. The long axis side light-shielding part 235 shields non zero-order diffraction light on the long axis side of the modulation beam L33. The scanning mechanism 237 is arranged between the third lens 233 and the fourth lens 234 so as to be adjacent to the long axis side light-shielding part 235. The scanning mechanism 237 scans the modulation beam L33 incident on the long axis side light-shielding part 235, or the modulation beam L33 having passed through the long axis side light-shielding part 235, in at least one of a long axis direction and a short axis direction. Thereby, the structure of the optical device can be simplified.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an optical device that irradiates and scans a spot light array on an object, and a three-dimensional shaping device including the optical device.

Background Art

[0002] In recent years, an SLS (Selective Laser Sintering) type three-dimensional shaping device that performs three-dimensional shaping by irradiating a shaping material such as metal powder or resin powder with modulated laser light and sintering the shaping material has been used.

[0003] For example, in the three-dimensional shaped object manufacturing device of Patent Document 1, a single-spot laser beam is irradiated and scanned on the upper surface of a powder layer by a laser beam irradiation unit 61 provided above the powder layer. The laser beam irradiation unit 61 includes an optical fiber connector 83 connected to a laser oscillator, a collimating lens 85 that converts the laser beam emitted from the optical fiber connector 83 into parallel light, a galvano optical scanner 89 that is a scanning mechanism for two-dimensionally scanning the laser beam that has passed through the collimating lens 85, and an Fθ lens 99 that condenses the laser beam scanned by the galvano optical scanner 89 and irradiates the powder layer.

[0004] In addition, in a three-dimensional shaping device, in order to improve productivity, it has been considered to form a linear pattern light using an optical modulator and simultaneously irradiate a plurality of light spots on a shaping material (that is, irradiate a spot light array) and scan.

[0005] In a three-dimensional shaping device that irradiates a spot light array, in order to increase the power density of the laser beam irradiated on the shaping material (that is, the light intensity per unit area), the optical modulator that forms the linear pattern light is irradiated with light having a high power density. At this time, when a linear laser beam having a Gaussian intensity distribution is irradiated on the optical modulator, the peak intensity (that is, the maximum intensity) on the modulation surface of the modulator becomes excessive, and there is a risk of damaging the optical modulator.

[0006] Therefore, in the three-dimensional shaping apparatus of Patent Document 2, it has been proposed to increase the amount of light input to the optical modulator without damaging the optical modulator by flattening the intensity distribution of the linear laser light incident on the optical modulator using a top-hat beam shaper.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] By the way, in the three-dimensional shaping apparatus of Patent Document 2, in order to achieve the above object, the illumination optical system and the projection optical system each include a relatively large number of lenses and the like. Further, although not detailed in Patent Document 2, the scanning unit of the three-dimensional shaping apparatus needs to include a plurality of optical elements (that is, a collimating lens, a galvanometer scanner, an Fθ lens, etc.) substantially the same as those in Patent Document 1 in order to form an image of the linear laser light that has passed through the projection optical system on the upper surface of the shaping material (that is, the surface to be scanned) and scan it. For this reason, in the three-dimensional shaping apparatus, there is a limit to simplifying the structure of the optical device that guides the laser light emitted from the light source to the surface to be scanned of the shaping material and scans it.

[0009] The present invention has been made in view of the above problems, and an object thereof is to simplify the structure of the optical device.

Means for Solving the Problems

[0010] Aspect 1 of the present invention is an optical device that irradiates and scans a spot light array on an object, comprising: a first optical system that shapes a laser beam into a shaped beam that is long in the major axis direction; an optical modulator that modulates the shaped beam to form a modulated beam having a pattern in the major axis direction; a second optical system that guides the modulated beam to a scanned surface of the object to form a spot light array extending in the major axis direction on the scanned surface and scans the spot light array on the scanned surface. The second optical system includes a minor-axis side light shielding portion disposed at a condensing position on the minor-axis side of the modulated beam to block non-zero order diffracted light on the minor-axis side of the modulated beam, a first projection optical element disposed between the minor-axis side light shielding portion and the scanned surface to condense the modulated beam in the major axis direction, a major-axis side light shielding portion disposed at a condensing position on the major-axis side of the modulated beam by the first projection optical element between the first projection optical element and the scanned surface to block non-zero order diffracted light on the major-axis side of the modulated beam, a second projection optical element disposed between the major-axis side light shielding portion and the scanned surface to converge the modulated beam that has passed through the major-axis side light shielding portion in the minor axis direction and condense it on the scanned surface to form a spot light array on the scanned surface, and a scanning mechanism disposed adjacent to the major-axis side light shielding portion between the first projection optical element and the second projection optical element to scan the modulated beam incident on the major-axis side light shielding portion or the modulated beam that has passed through the major-axis side light shielding portion in at least one of the major axis direction and the minor axis direction. The second optical system optically conjugates the modulation surface of the optical modulator and the scanned surface in the major axis direction.

[0011] Aspect 2 of the present invention is the optical device according to Aspect 1, wherein the scanning mechanism is a galvanometer scanner that changes the reflection direction of the modulated beam.

[0012] Aspect 3 of the present invention is the optical device of Aspect 2, wherein the galvanometer scanner is disposed adjacent to the long-axis side light-shielding portion between the first projection optical element and the long-axis side light-shielding portion, and changes the reflection direction of the modulation beam in one of the long-axis direction and the short-axis direction by rotation. A first galvanometer mirror, and a second galvanometer mirror disposed adjacent to the long-axis side light-shielding portion between the long-axis side light-shielding portion and the second projection optical element, and changing the reflection direction of the modulation beam in the other of the long-axis direction and the short-axis direction by rotation.

[0013] Aspect 4 of the present invention is the optical device of Aspect 3, wherein the first galvanometer mirror changes the reflection direction of the modulation beam in the short-axis direction.

[0014] Aspect 5 of the present invention is the optical device of Aspect 1 (which may be any one of Aspects 1 to 4), wherein the first optical system includes a beam shaper that converts the intensity distribution of the laser beam in the long-axis direction from a Gaussian distribution to make the intensity distribution of the shaped beam in the long-axis direction on the modulation surface a top-hat distribution.

[0015] Aspect 6 of the present invention is the optical device of Aspect 5, wherein the beam shaper also makes the intensity distribution of the shaped beam in the short-axis direction on the modulation surface a top-hat distribution by converting the intensity distribution of the laser beam in the short-axis direction from a Gaussian distribution.

[0016] Aspect 7 of the present invention is the optical device of Aspect 1 (which may be any one of Aspects 1 to 6), wherein no optical element is disposed between the scanning mechanism and the long-axis side light-shielding portion.

[0017] Aspect 8 of the present invention is the optical device of Aspect 1 (which may be any one of Aspects 1 to 7), wherein the optical modulator is a PLV.

[0018] Aspect 9 of the present invention is a three-dimensional shaping apparatus, comprising any one of the optical apparatuses of Aspects 1 to 8, a laser light source that emits the laser light to the optical apparatus, and a material holding unit that holds a shaping material, which is an object irradiated with the modulated beam from the optical apparatus.

Advantages of the Invention

[0019] In the present invention, the structure of the optical apparatus can be simplified.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0021] FIG. 1 is a diagram showing the configuration of a three-dimensional shaping apparatus 1 according to the first embodiment of the present invention. The three-dimensional shaping apparatus 1 is an SLS (Selective Laser Sintering) type three-dimensional shaping apparatus that performs three-dimensional shaping by irradiating a powder-like or paste-like shaping material with laser light modulated thereto to sinter or melt the shaping material. The shaping material is, for example, metal, engineering plastic, ceramics, synthetic resin, or the like. The shaping material may include a plurality of types of materials.

[0022] The three-dimensional shaping apparatus 1 includes a laser light source 11, an optical device 12, and a material supply mechanism 14. In FIG. 1, the material supply mechanism 14 is shown in a longitudinal section. In the three-dimensional shaping apparatus 1, the laser light L31 emitted from the laser light source 11 is guided by the optical device 12 to the material supply mechanism 14 and scanned on the shaping material 91 within the shaping space 140 of the material supply mechanism 14. As a result, the portion of the shaping material 91 irradiated with the laser light is sintered. Then, by repeating the supply of the shaping material 91 to the shaping space 140 and the scanning of the laser light on the shaping material 91, a three-dimensional shaped object is formed. In FIG. 1, for ease of understanding of the figure, each component of the optical device 12 is surrounded by a two-dot chain line.

[0023] In the three-dimensional shaping apparatus 1, based on design data (e.g., CAD data) of the three-dimensional shaped object to be manufactured, etc., the configurations of the laser light source 11, the optical device 12, the material supply mechanism 14, etc. are controlled by a control unit (not shown). The control unit is, for example, a normal computer including a processor, a memory, an input / output unit, and a bus. Note that the configuration of the control unit may be changed in various ways.

[0024] The laser light source 11 emits the laser light L31 to 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. Note that the type of the laser light source 11 and the wavelength of the laser light L31 may be changed in various ways.

[0025] The optical device 12 modulates the laser light L31 from the laser light source 11 into a modulated beam L33 and irradiates the upper surface 92 (hereinafter also referred to as the "scanned surface 92") of the shaping material 91 within the shaping space 140. On the scanned surface 92, a spot light array in which a plurality of spot lights are arranged substantially linearly is formed by the modulated beam L33 guided by the optical device 12. The optical device 12 also scans the spot light array on the scanned surface 92.

[0026] The optical device 12 includes a first optical system 21, a light modulator 22, and a second optical system 23. As will be described later, the first optical system 21 and the second optical system 23 each include a plurality of optical elements such as lenses. The first optical system 21 is an illumination optical system that guides the laser beam L31 from the laser light source 11 to the light modulator 22. The second optical system 23 is an optical system that incorporates a scanning mechanism for scanning the modulated beam L33 on the scanned surface 92 of the shaping material 91 inside the projection optical system that guides the modulated beam L33 from the light modulator 22 to the scanned surface 92.

[0027] The first optical system 21 shapes the laser beam L31 from the laser light source 11 into a substantially rectangular shaped beam L32 that is long 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 shaped beam L32 is a substantially rectangle that is long in the long axis direction and short in the short axis direction perpendicular to the long axis direction. The shaped beam L32 refers to the light beam from when it passes through the first optical system 21 until it enters the light modulator 22.

[0028] The above-described long axis direction and short axis direction are directions perpendicular to the traveling direction (i.e., the optical axis direction) of the shaped beam L32. Also, the cross-sectional shape of the shaped beam L32 is the shape of the shaped beam L32 in a plane perpendicular to the optical axis direction of the shaped beam L32. In the following description, the cross-section of light means, as described above, the cross-section of the light in a plane perpendicular to the optical axis direction of the light. The cross-sectional shape of the shaped beam L32 can also be regarded as a substantially straight line extending in the long axis direction. The shape of the irradiation region of the shaped beam L32 on the light modulator 22 is, for example, a substantially rectangle with a length of about 28 mm in the long axis direction and a length of about 1 mm in the short axis direction.

[0029] The light modulator 22 forms a modulated beam L33 having a pattern in the long axis direction by modulating the shaped beam L32 from the first optical system 21 and guides it to the second optical system 23. As the light modulator 22, for example, an LPLV (Liner Planar Light Valve), which is a type of PLV (Planar Light Valve), is used.

[0030] FIG. 2 is a diagram showing a simplified structure of the optical modulator 22 (i.e., LPLV). The optical modulator 22 includes a plurality of substantially rectangular pixels 221 arranged in a matrix (i.e., two-dimensionally arranged) adjacent to each other on a substrate (not shown). In the optical modulator 22, the surfaces of the plurality of pixels 221 serve as modulation surfaces. In the example shown in FIG. 2, M pixels 221 are arranged in the vertical direction and N pixels 221 are arranged in the horizontal direction in the figure. The horizontal direction in FIG. 2 corresponds to the major axis direction of the shaped beam L32 (see FIG. 1), and the vertical direction in FIG. 2 corresponds to the minor axis direction of the shaped beam L32.

[0031] Each pixel 221 is a modulation element including a fixed member 222 and a movable member 223. The fixed member 222 is a planar substantially rectangular member fixed to the substrate, and a substantially circular opening is provided at the center. The movable member 223 is a substantially circular member provided in the opening of the fixed member 222. A fixed reflecting surface is provided on the upper surface of the fixed member 222 (i.e., the front surface in the direction perpendicular to the paper surface in FIG. 2). A movable reflecting surface is provided on the upper surface of the movable member 223. The movable member 223 is movable in the direction perpendicular to the paper surface in FIG. 2.

[0032] In each pixel 221, when the relative position between the fixed member 222 and the movable member 223 in the direction perpendicular to the paper surface in FIG. 2 is changed, the reflected light from the pixel 221 is switched between the zero-order light (i.e., the specularly reflected light) and the non-zero-order diffracted light. In other words, in the pixel 221, optical modulation using a diffraction grating is performed by the relative movement of the movable member 223 with respect to the fixed member 222. The zero-order light generated by the optical modulator 22 is guided to the scanned surface 92 of the shaping material 91 by the second optical system 23 (see FIG. 1). Also, the non-zero-order diffracted light generated by the optical modulator 22 is blocked by the second optical system 23 and does not reach the scanned surface 92 of the shaping material 91. The above-mentioned non-zero-order diffracted light is mainly the first-order diffracted light (i.e., the (+1)-order diffracted light and the (-1)-order diffracted light), and also includes diffracted light of the second order or higher.

[0033] In the optical modulator 22, the diffraction states of the reflected light from the M pixels 221 arranged in a column in the vertical direction in FIG. 2 (hereinafter also referred to as a "pixel column") are the same. That is, when the reflected light from one pixel 221 is the zero-order light, the reflected light from all the other pixels 221 (i.e., M - 1 pixels 221) in the pixel column containing the one pixel 221 is also the zero-order light. Also, when the reflected light from one pixel 221 is non-zero-order diffracted light, the reflected light from all the other pixels 221 in the pixel column containing the one pixel 221 is also non-zero-order diffracted light. That is, in the optical modulator 22, modulation is not performed in the short-axis direction of the shaping beam L32, and modulation is performed in the long-axis direction.

[0034] In the second optical system 23, for the N pixel columns arranged in a column in the long-axis direction of the shaping beam L32 on the optical modulator 22, the reflected light from the M pixels 221 included in each pixel column is integrated and guided to the scanned surface 92 of the shaping material 91, and N spot lights (i.e., a spot light array extending in the long-axis direction) arranged in the long-axis direction are formed on the scanned surface 92. Thereby, the power density of each spot light in the spot light array can be increased.

[0035] Note that in the optical modulator 22, the M pixels 221 (i.e., M modulation elements) of one pixel column can also be regarded as one modulation element corresponding to one unit space. The optical modulator 22 functions as an optical modulator including N modulation elements arranged in a column in the long-axis direction of the shaping beam L32 on the optical modulator 22.

[0036] The material supply mechanism 14 shown in Fig. 1 includes a shaping part 141 and a supply part 142. The shaping part 141 includes a first cylinder 143 and a first piston 144. The first cylinder 143 is a cylindrical member extending in the vertical direction. The shape of the internal space of the first cylinder 143 in plan view is, for example, substantially rectangular. The first piston 144 is a substantially flat plate-shaped or substantially columnar member accommodated in the internal space of the first cylinder 143, and the shape in plan view is substantially the same as the internal space of the first cylinder 143. The first piston 144 is movable in the vertical direction within the internal space of the first cylinder 143. In the shaping part 141, the three-dimensional space surrounded by the inner surface of the first cylinder 143 and the upper surface of the first piston 144 becomes a shaping space 140 where three-dimensional shaping by the modulated beam L33 is performed.

[0037] The supply part 142 includes a second cylinder 145, a second piston 146, and a squeegee 147. The second cylinder 145 is a cylindrical member extending in the vertical direction and is arranged adjacent to the side of the first cylinder 143. The shape of the internal space of the second cylinder 145 in plan view is, for example, substantially rectangular. The second piston 146 is a substantially flat plate-shaped or substantially columnar member accommodated in the internal space of the second cylinder 145, and the shape in plan view is substantially the same as the internal space of the second cylinder 145. The second piston 146 is movable in the vertical direction within the internal space of the second cylinder 145. In the supply part 142, the three-dimensional space surrounded by the inner surface of the second cylinder 145 and the upper surface of the second piston 146 becomes a storage space where the shaping material 91 to be supplied to the shaping part 141 is stored. The squeegee 147 is a rod-shaped (for example, substantially cylindrical) member extending horizontally across the upper opening of the second cylinder 145. The squeegee 147 is movable horizontally along the upper end surface of the second cylinder 145.

[0038] In the supply unit 142, the second piston 146 rises by a predetermined distance, and the shaping material 91 in the second cylinder 145 is lifted upward. Then, as the squeegee 147 moves from above the second cylinder 145 to above the first cylinder 143, the shaping material 91 protruding above the upper end surface of the second cylinder 145 is supplied into and held in the shaping space 140 of the shaping unit 141. The shaping unit 141 is a material holding unit that holds the shaping material 91, which is an object irradiated with the modulated beam L33 from the optical device 12. The scanned surface 92, which is the upper surface of the shaping material 91 held in the shaping space 140, is located at a predetermined height (for example, the same height as the upper end surface of the first cylinder 143).

[0039] In the three-dimensional shaping apparatus 1, the shaping material 91 in the shaping space 140 is scanned with the spot light array formed by the above-described modulated beam L33. As a result, in the surface layer portion of the shaping material 91 in the shaping space 140, the portion irradiated with the modulated beam L33 is sintered, and a portion corresponding to one layer when the three-dimensional shaped object is divided into a plurality of layers laminated in the vertical direction is formed. When the scanning of the spot light array with respect to the shaping material 91 in the shaping space 140 is completed, the first piston 144 descends by a predetermined distance. Thereafter, as described above, the shaping material 91 is supplied from the supply unit 142 to the shaping space 140, and the spot light array is scanned. In the three-dimensional shaping apparatus 1, the supply of the shaping material 91 to the shaping space 140 and the scanning of the spot light array with respect to the shaping material 91 in the shaping space 140 are repeated, whereby a three-dimensional shaped object is formed in the shaping space 140.

[0040] Next, the detailed structure of the optical device 12 will be described with reference to FIGS. 3 and 4. FIGS. 3 and 4 are diagrams schematically showing the optical paths of the laser beam L31, the shaped beam L32, and the modulated beam L33 in the optical device 12. In the optical device 12 illustrated in FIG. 1, the first optical system 21 and the second optical system 23 are arranged obliquely (that is, the optical axis of the first optical system 21 and the optical axis of the second optical system 23 intersect), but in FIGS. 3 and 4, for ease of understanding of the drawings, the positions of the first optical system 21 and the second optical system 23 are changed so that the optical axis of the first optical system 21 and the optical axis of the second optical system 23 are in a straight line. The same applies to FIGS. 7 and 8 described later.

[0041] In FIG. 3, the optical paths of the shaped beam L32 and the modulated beam L33 are shown such that the short-axis direction of the shaped beam L32 and the modulated beam L33 coincides with the direction perpendicular to the paper surface. In FIG. 3, the long-axis direction of the shaped beam L32 and the modulated beam L33 coincides with the vertical direction in the figure. Also, in FIG. 4, the optical paths of the shaped beam L32 and the modulated beam L33 are shown such that the long-axis direction of the shaped beam L32 and the modulated beam L33 coincides with the direction perpendicular to the paper surface. In FIG. 4, the short-axis direction of the shaped beam L32 and the modulated beam L33 coincides with the vertical direction in the figure. The same applies to FIGS. 7 and 8 described later.

[0042] The first optical system 21 of the optical device 12 includes a collimating lens 211, a beam shaper 213, and a beam expander 216. The collimating lens 211, the beam shaper 213, and the beam expander 216 are arranged in this order in the optical axis direction from the laser light source 11 toward the optical modulator 22. The collimating lens 211 generates parallel light from the laser beam L31. The lens shape of the collimating lens 211 may be spherical, aspherical, or cylindrical. In the examples shown in FIGS. 3 and 4, the collimating lens 211 is composed of a single lens, but it may be composed of a plurality of lenses.

[0043] The beam shaper 213 is a top-hat beam shaper that converts the intensity distribution in the major axis direction and the minor axis direction in the cross-section of the collimated beam with a Gaussian distribution incident on the beam shaper 213 (hereinafter, also simply referred to as "intensity distribution") from a Gaussian distribution to a top-hat distribution with a wide width of the maximum intensity region (i.e., a substantially flat top). The beam shaper 213 is, for example, a single optical element. In the present embodiment, the beam shaper 213 is an aspherical concave lens. Note that, as the beam shaper 213, various optical elements other than the aspherical concave lens (for example, refractive optical elements such as free-form lenses, or diffractive optical elements (DOE: Diffractive Optical Element)) may be used.

[0044] The beam expander 216 enlarges the rectangular image generated by passing through the beam shaper 213 at different magnifications in the directions of the major axis and the minor axis, and forms an image on the modulation surface of the optical modulator 22. The beam expander 216 includes a cylindrical lens 214a and a cylindrical lens 214b for enlarging the rectangular image in the major axis direction. The beam expander 216 also includes a cylindrical lens 215a and a cylindrical lens 215b for enlarging the rectangular image in the minor axis direction. In the examples shown in FIGS. 3 and 4, in the optical axis direction from the laser light source 11 toward the optical modulator 22, the cylindrical lens 214a, the cylindrical lens 215a, the cylindrical lens 214b, and the cylindrical lens 215b are arranged in this order.

[0045] Note that, in the first optical system 21, optical elements other than those described above may be added. Also, the configuration of the beam expander 216 may be variously changed. In the first optical system 21, the beam expander 216 is not necessarily provided. For example, a beam shaper 213 that directly forms a rectangular image of a desired size on the modulation surface of the optical modulator 22 may be used.

[0046] As described above, the first optical system 21 converts the laser beam L31 emitted from the laser light source 11 into a collimated beam and guides it to the optical modulator 22. The intensity distributions in the major axis direction and the minor axis direction in the cross section of the laser beam L31 incident on the first optical system 21 are Gaussian distributions, respectively. In practice, these intensity distributions may not be exact Gaussian distributions but may be distributions with shapes approximated by Gaussian functions. In the following description, however, both exact Gaussian distributions and distributions approximated by Gaussian distributions are collectively referred to as "Gaussian distributions".

[0047] In the first optical system 21, the laser beam L31 emitted from the laser light source 11 passes through the collimating lens 211 and becomes a collimated beam that is parallel light in the major axis direction and the minor axis direction. The collimated beam passes through the beam shaper 213 and the beam expander 216 and is guided to the optical modulator 22. The intensity distribution of the collimated beam before entering the beam shaper 213 is a Gaussian distribution in the major axis direction and also a Gaussian distribution in the minor axis direction, as shown by being surrounded by a rectangular frame on the lower side of the optical path diagrams in FIGS. 3 and 4.

[0048] The intensity distributions in the major axis direction and the minor axis direction of the collimated beam are converted from a Gaussian distribution to a top-hat distribution (also called a rectangular distribution) as shown by being surrounded by a rectangular frame on the lower side of the optical path diagrams in FIGS. 3 and 4 by passing through the beam shaper 213. Also, the intensity distributions in the major axis direction and the minor axis direction of the collimated beam are maintained as a top-hat distribution when passing through the beam expander 216. Therefore, the intensity distribution of the shaped beam L32 incident on the optical modulator 22 after passing through the first optical system 21 (that is, the intensity distribution of the shaped beam L32 on the modulation surface of the optical modulator 22) is a top-hat distribution in both the major axis direction and the minor axis direction.

[0049] The second optical system 23 includes a first lens 231, a second lens 232, a third lens 233, a fourth lens 234, a long-axis side light-shielding portion 235, a short-axis side light-shielding portion 236, and a scanning mechanism 237. The first lens 231 and the second lens 232 are, for example, cylindrical convex lenses. The third lens 233 and the fourth lens 234 are, for example, spherical convex lenses. The long-axis side light-shielding portion 235 is, for example, a flat plate member provided with a rectangular opening 2350 extending in parallel with the short-axis direction at the center. The short-axis side light-shielding portion 236 is, for example, a flat plate member provided with a rectangular opening 2360 extending in parallel with the long-axis direction at the center. The materials of the long-axis side light-shielding portion 235 and the short-axis side light-shielding portion 236 are, for example, metals such as stainless steel or ceramics.

[0050] In this embodiment, the scanning mechanism 237 is a galvanometer scanner. The scanning mechanism 237 includes a first galvanometer mirror 371, a second galvanometer mirror 372, a first galvanometer motor (not shown), and a second galvanometer motor (not shown). The first galvanometer motor changes the reflection direction of the modulation beam L33 by the first galvanometer mirror 371 by rotating the first galvanometer mirror 371. The second galvanometer motor changes the reflection direction of the modulation beam L33 by the second galvanometer mirror 372 by rotating the second galvanometer mirror 372.

[0051] The second lens 232 and the third lens 233 are located on the scanned surface 92 side of the first lens 231 (i.e., the side opposite to the optical modulator 22) in the optical axis direction. In other words, the second lens 232 and the third lens 233 are located closer to the scanned surface 92 than the first lens 231 on the optical axis. In the examples shown in FIGS. 3 and 4, the third lens 233 is located on the scanned surface 92 side of the second lens 232 (i.e., the side opposite to the first lens 231) in the optical axis direction. In other words, the second lens 232 is located between the first lens 231 and the third lens 233. Note that the third lens 233 may be disposed between the first lens 231 and the second lens 232. The fourth lens 234 is located on the scanned surface 92 side of the first lens 231, the second lens 232, and the third lens 233 in the optical axis direction. In other words, the fourth lens 234 is located closer to the scanned surface 92 than the first lens 231, the second lens 232, and the third lens 233 on the optical axis.

[0052] In the second optical system 23 illustrated in FIGS. 3 and 4, on the optical axis from the optical modulator 22 toward the scanned surface 92, the first lens 231, the short-axis side light shielding portion 236, the second lens 232, the third lens 233, the long-axis side light shielding portion 235, and the fourth lens 234 are arranged in this order.

[0053] The short-axis side light shielding portion 236 is disposed near the condensing position on the short-axis side of the modulation beam L33 between the first lens 231 and the second lens 232 and the third lens 233. Specifically, when the focal length of the first lens 231 is f1, the first-order diffraction angle from the optical modulator 22 in the short-axis direction is θ1, and the angle (NA) of the light incident on and condensed by the short-axis side light shielding portion 236 is θ2, the short-axis side light shielding portion 236 is preferably disposed within (f1 / 2)×(tanθ1 / tanθ2) from the condensing position on the optical axis, and more preferably disposed at the condensing position. The short-axis side light shielding portion 236 is disposed, for example, at the rear focal position on the short-axis side of the first lens 231.

[0054] The long-axis side light-shielding part 235 is disposed near the condensing position on the long-axis side of the modulation beam L33 between the third lens 233 and the fourth lens 234. Specifically, when the focal length of the third lens 233 is f3, the first diffraction angle from the optical modulator 22 in the long-axis direction is θ3, and the angle (NA) of the light that enters and is condensed on the long-axis side light-shielding part 235 is θ4, the long-axis side light-shielding part 235 is preferably disposed within (f3 / 2)×(tanθ3 / tanθ4) on the optical axis at the condensing position, and more preferably disposed at the condensing position. The position where the long-axis side light-shielding part 235 is disposed is, for example, near the rear focal position of the third lens 233.

[0055] In the second optical system 23, a scanning mechanism 237 is also disposed between the third lens 233 and the fourth lens 234 on the optical axis. The scanning mechanism 237 is disposed adjacent to and near the long-axis side light-shielding part 235. In the optical axis direction, the distance between the scanning mechanism 237 and the long-axis side light-shielding part 235 is smaller than the distance between the scanning mechanism 237 and the third lens 233 and the distance between the scanning mechanism 237 and the fourth lens 234.

[0056] Specifically, the first galvanometer mirror 371 of the scanning mechanism 237 is disposed on the optical modulator 22 side of the long-axis side light-shielding part 235 in the optical axis direction. In other words, the first galvanometer mirror 371 is located between the second lens 232 and the third lens 233 and the long-axis side light-shielding part 235 on the optical axis. In the optical axis direction, the distance between the first galvanometer mirror 371 and the long-axis side light-shielding part 235 is smaller than the distance between the first galvanometer mirror 371 and the third lens 233 and the distance between the first galvanometer mirror 371 and the second lens 232. The second galvanometer mirror 372 is disposed on the scanned surface 92 side of the long-axis side light-shielding part 235 in the optical axis direction. In other words, the second galvanometer mirror 372 is located between the long-axis side light-shielding part 235 and the fourth lens 234 on the optical axis. In the optical axis direction, the distance between the second galvanometer mirror 372 and the long-axis side light-shielding part 235 is smaller than the distance between the second galvanometer mirror 372 and the fourth lens 234.

[0057] The first galvanometer mirror 371 and the second galvanometer mirror 372 are each arranged in the vicinity of the long-axis side light-shielding portion 235 adjacent to the long-axis side light-shielding portion 235. The distance between the first galvanometer mirror 371 and the long-axis side light-shielding portion 235 in the optical axis direction is, for example, 10 mm to 20 mm. The distance between the long-axis side light-shielding portion 235 and the second galvanometer mirror 372 in the optical axis direction is, for example, 10 mm to 20 mm. The distance between the first galvanometer mirror 371 and the long-axis side light-shielding portion 235 in the optical axis direction and the distance between the long-axis side light-shielding portion 235 and the second galvanometer mirror 372 in the optical axis direction may be different, but are preferably substantially the same.

[0058] In the optical device 12 illustrated in FIGS. 3 and 4, it is preferable that no optical elements other than those illustrated are provided. For example, between the third lens 233 and the fourth lens 234 on the optical axis, no optical elements other than the long-axis side light-shielding portion 235 and the scanning mechanism 237 are arranged. Naturally, no other optical elements are arranged between the third lens 233 and the first galvanometer mirror 371 and between the first galvanometer mirror 371 and the long-axis side light-shielding portion 235. Therefore, the modulated beam L33 that has passed through the third lens 233 is incident directly (that is, without passing through other optical elements) on the first galvanometer mirror 371, and the modulated beam L33 reflected by the first galvanometer mirror 371 is incident directly (that is, without passing through other optical elements) on the long-axis side light-shielding portion 235.

[0059] Also, no other optical elements are arranged between the long-axis side light-shielding portion 235 and the second galvanometer mirror 372 and between the second galvanometer mirror 372 and the fourth lens 234. Therefore, the modulated beam L33 that has passed through the long-axis side light-shielding portion 235 is incident directly (that is, without passing through other optical elements) on the second galvanometer mirror 372, and the modulated beam L33 reflected by the second galvanometer mirror 372 is incident directly (that is, without passing through other optical elements) on the fourth lens 234.

[0060] In addition, when the third lens 233 is disposed between the first lens 231 and the second lens 232, it is preferable that no optical element other than the long-axis side light shielding portion 235 and the scanning mechanism 237 is disposed between the second lens 232 and the fourth lens 234 on the optical axis.

[0061] In the second optical system 23, it is preferable that the front focal position on the short-axis side of the first lens 231 (i.e., the focal position on the light modulator 22 side) coincides with the modulation surface of the light modulator 22. In this way, by setting the distance between the light modulator 22 and the first lens 231 to be equal to or less than (preferably less than) the front focal length of the first lens 231, the distance between the focal points of the zero-order diffracted light and the first-order diffracted light generated after passing through the first lens 231 is increased. As a result, the zero-order diffracted light can be easily separated from non-zero-order diffracted lights such as the first-order diffracted light.

[0062] In the second optical system 23, further, the front focal position of the third lens 233 coincides with the modulation surface of the light modulator 22. The rear focal position on the short-axis side of the first lens 231 (i.e., the focal position on the scanned surface 92 side) coincides with the front combined focal position on the short-axis side of the second lens 232 and the third lens 233. The rear focal position of the third lens 233 coincides with the front focal position of the fourth lens 234. The rear focal position of the fourth lens 234 coincides with the scanned surface 92 of the shaping material 91.

[0063] In the second optical system 23, the modulation surface of the optical modulator 22 and the scanned surface 92 of the shaping material 91 are optically conjugated in the major axis direction by the third lens 233 and the fourth lens 234. Also, in the minor axis direction, the modulation surface of the optical modulator 22 and the front focal position of the fourth lens 234 are optically conjugated by the first lens 231, the second lens 232, and the third lens 233. The fourth lens 234 condenses the modulated beam L33 on the scanned surface 92 in the minor axis direction. The scanned surface 92 is optically conjugated with the rear focal position of the first lens 231 in the minor axis direction by the second lens 232, the third lens 233, and the fourth lens 234. In other words, in the minor axis direction, the minor axis side light shielding portion 236 and the scanned surface 92 are optically conjugated by the second lens 232, the third lens 233, and the fourth lens 234.

[0064] Note that in the second optical system 23, the types of the first lens 231, the second lens 232, the third lens 233, and the fourth lens 234 may be variously changed, and optical elements other than those described above may be added. Also, the materials, shapes, and structures of the major axis side light shielding portion 235 and the minor axis side light shielding portion 236 may be variously changed.

[0065] As described above, the second optical system 23 guides the modulated beam L33 from the optical modulator 22 to the scanned surface 92 of the shaping material 91, forms a spot light array on the scanned surface 92, and scans the spot light array on the scanned surface 92.

[0066] Specifically, the modulated beam L33, which is parallel light generated by the optical modulator 22, is condensed at the rear focal position of the first lens 231 (i.e., the front combined focal position of the second lens 232 and the third lens 233) in the minor axis direction by passing through the first lens 231. The modulated beam L33 does not refract when passing through the first lens 231 in the major axis direction.

[0067] The modulated beam L33 that has passed through the first lens 231 passes through the aperture 2360 of the minor-axis side light shielding portion 236 located at the rear focal position on the minor-axis side of the first lens 231. Specifically, among the reflected light reflected by the optical modulator 22, the zero-order light and the non-zero-order diffracted light on the major-axis side pass through the rectangular aperture 2360 of the minor-axis side light shielding portion 236. Also, among the reflected light reflected by the optical modulator 22, the non-zero-order diffracted light on the minor-axis side (mainly the first-order diffracted light) is blocked by the minor-axis side light shielding portion 236. As shown in FIG. 5, the non-zero-order diffracted light on the minor-axis side is irradiated onto a substantially linear irradiation region 81 extending in the major-axis direction at positions above and below (i.e., on both sides in the minor-axis direction of the aperture 2360) the aperture 2360 of the minor-axis side light shielding portion 236.

[0068] The cross-section of the modulated beam L33 that has passed through the aperture 2360 of the minor-axis side light shielding portion 236 spreads in the minor-axis direction as it moves away from the minor-axis side light shielding portion 236 in the optical axis direction. The modulated beam L33 that has passed through the minor-axis side light shielding portion 236 becomes parallel light by passing through the second lens 232 in the minor-axis direction and does not refract when passing through the third lens 233. Note that the modulated beam L33 that has passed through the minor-axis side light shielding portion 236 may become parallel light when passing through the third lens 233 by refracting when passing through the second lens 232 and the third lens 233, respectively, in the minor-axis direction. The modulated beam L33 does not refract when passing through the second lens 232 in the major-axis direction and is focused on the rear focal position of the third lens 233 (i.e., the front focal position of the fourth lens 234) by passing through the third lens 233.

[0069] The modulated beam L33 that has passed through the second lens 232 and the third lens 233 is incident on the first galvanometer mirror 371 of the scanning mechanism 237. Specifically, among the modulated beam L33, the zero-order light is incident on the first galvanometer mirror 371, and the non-zero-order diffracted light on the major axis side (mainly the first-order diffracted light) is not incident on the first galvanometer mirror 371. The zero-order light of the modulated beam L33 reflected by the first galvanometer mirror 371 passes through the aperture 2350 of the major-axis side light-shielding portion 235. In the scanning mechanism 237, the first galvanometer mirror 371 is rotated by the first galvanometer motor, so that the reflection direction of the zero-order light by the first galvanometer mirror 371 in the minor axis direction is changed. As a result, in the major-axis side light-shielding portion 235 arranged at the condensing position on the major axis side of the modulated beam L33, the position of the zero-order light passing through the aperture 2350 in the minor axis direction is changed.

[0070] On the other hand, the non-zero-order diffracted light on the major axis side of the modulated beam L33 is not incident on the first galvanometer mirror 371 as described above, and is directly incident on and blocked by the major-axis side light-shielding portion 235. As shown in FIG. 6, the non-zero-order diffracted light on the major axis side is irradiated on a substantially linear irradiation region 82 extending in the minor axis direction at positions on the left and right sides (i.e., both sides in the major axis direction of the aperture 2350) in the figure rather than the aperture 2350 of the major-axis side light-shielding portion 235.

[0071] The cross section of the modulated beam L33 (i.e., the zero-order light) that has passed through the aperture 2350 of the major-axis side light-shielding portion 235 spreads in the major axis direction as it moves away from the major-axis side light-shielding portion 235 in the optical axis direction. The modulated beam L33 that has passed through the aperture 2350 of the major-axis side light-shielding portion 235 is incident on the second galvanometer mirror 372 of the scanning mechanism 237. The modulated beam L33 reflected by the second galvanometer mirror 372 is incident on the fourth lens 234. In the scanning mechanism 237, the second galvanometer mirror 372 is rotated by the second galvanometer motor, so that the reflection direction of the modulated beam L33 by the second galvanometer mirror 372 in the major axis direction is changed. As a result, the position of the modulated beam L33 incident on the fourth lens 234 in the major axis direction is changed.

[0072] The modulated beam L33 passes through the fourth lens 234 and becomes parallel light in the major axis direction and is incident on the scanned surface 92 of the shaping material 91. Further, the modulated beam L33 that is incident on the fourth lens 234 as parallel light in the minor axis direction is condensed in the minor axis direction on the scanned surface 92 located at the rear focal position of the fourth lens 234 by passing through the fourth lens 234.

[0073] As described above, in the major axis direction, the modulation surface of the optical modulator 22 and the scanned surface 92 of the shaping material 91 are optically conjugate. Also, the intensity distribution in the major axis direction of the collimated beam on the modulation surface of the optical modulator 22 is a top-hat distribution as shown in the rectangular frame of FIG. 3. Therefore, the intensity distribution in the major axis direction of the modulated beam L33 on the scanned surface 92 also becomes a top-hat distribution. In other words, the intensity distribution in the major axis direction of the spot light array formed on the scanned surface 92 by the modulated beam L33 becomes a top-hat distribution.

[0074] Also, in the minor axis direction, the modulation surface of the optical modulator 22 and the front focal position of the fourth lens 234 (that is, the rear focal position of the third lens 233) are optically conjugate. Also, the intensity distribution in the minor axis direction of the collimated beam on the modulation surface of the optical modulator 22 is converted into a top-hat distribution by the beam shaper 213 as shown in the rectangular frame of FIG. 4. Therefore, the intensity distribution in the minor axis direction of the modulated beam L33 that has passed through the third lens 233 becomes a top-hat distribution at the front focal position of the fourth lens 234.

[0075] Therefore, due to the Fourier transform effect of the fourth lens 234, the intensity distribution in the minor axis direction of the modulated beam L33 at the focus point (i.e., the above-mentioned spot light array) on the scanned surface 92 of the shaping material 91 is a distribution obtained by squaring the sinc function. In reality, the intensity distribution in the minor axis direction of the modulated beam L33 may not be a distribution obtained by strictly squaring the sinc function, but may be a distribution with a shape approximated to the square of the sinc function. However, in the following description, the distribution obtained by strictly squaring the sinc function and the distribution approximated to the square of the sinc function are collectively referred to as the "squared sinc function distribution". Since the squared sinc function distribution has a main peak, similar to the Gaussian distribution, the modulated beam L33 can be preferably focused on the scanned surface 92.

[0076] In the three-dimensional shaping apparatus 1, when the first galvanometer mirror 371 rotates in the scanning mechanism 237 of the optical apparatus 12, the above-mentioned spot light array is scanned on the scanned surface 92 of the shaping material 91 in the direction corresponding to the minor axis direction (i.e., the direction perpendicular to the arrangement direction of the plurality of spot lights in the spot light array). Also, when the second galvanometer mirror 372 rotates in the scanning mechanism 237, the above-mentioned spot light array is scanned on the scanned surface 92 of the shaping material 91 in the direction corresponding to the major axis direction (i.e., the direction parallel to the arrangement direction of the plurality of spot lights in the spot light array). In the three-dimensional shaping apparatus 1, by repeating the scanning of the spot light array on the shaping material 91 and the supply of the shaping material 91 into the shaping space 140, a three-dimensional shaped object is formed.

[0077] The size of the modulated beam L33 on the scanned surface 92 of the shaping material 91 is obtained as follows. For example, the wavelength λ of the laser beam L31 is 1.070 μm, and the irradiation region on the modulation surface of the optical modulator 22 is assumed to be substantially linear (or substantially rectangular) with a length L1 of 28 mm in the major axis direction and a length L2 of 1 mm in the minor axis direction. The focal lengths f1 and f2 on the minor axis side of the first lens 231 and the second lens 232 are 40 mm and 400 mm, respectively, and the focal lengths f3 and f4 of the third lens 233 and the fourth lens 234 are 240 mm and 240 mm, respectively. The distance d between the second lens 232 and the third lens 233 is assumed to be 50 mm. In this case, the combined focal length f 23 on the minor axis side of the second lens 232 and the third lens 233 is approximately 163 mm.

[0078] Regarding the minor axis direction, as described above, the modulated beam L33 is focused on the rear focal position of the first lens 231 (i.e., the position where the minor axis side light shielding portion 236 is arranged). The focusing width of the modulated beam L33 in the minor axis direction at the rear focal position of the first lens 231 (i.e., the width between the first dark lines of the squared sinc function distribution) d S1 is 2.0xλxf1 / L2 ≒ 86 μm. The rear focal position of the first lens 231 is optically conjugate to the scanned surface 92 of the shaping material 91 in the minor axis direction. Therefore, the focusing diameter of the modulated beam L33 in the minor axis direction on the scanned surface 92 is 86 μmxf4 / f 23 ≒ 126 μm.

[0079] Regarding the major axis direction, as described above, the modulated beam L33 is focused on the rear focal position of the third lens 233. The focusing width of the modulated beam L33 in the major axis direction at the rear focal position of the third lens 233 (i.e., the width between the first dark lines of the squared sinc function distribution) d L3 is 2.0xλxf3 / L1 ≒ 18 μm. Note that the length L3 of the modulated beam L33 in the minor axis direction at the rear focal position of the third lens 233 is L2xf 23 / f1 = 4 mm. In the major axis direction, the modulation plane of the optical modulator 22 and the scanned surface 92 of the shaping material 91 are optically conjugate. Therefore, the length of the modulation beam L33 in the major axis direction on the scanned surface 92 is L1xf4 / f3 = 28 mm.

[0080] As described above, since the short-axis side light shielding portion 236 is disposed at the rear focal position of the first lens 231, the irradiation regions 81 (see FIG. 5) of the first-order diffracted light (i.e., the (+1)-order diffracted light and the (-1)-order diffracted light) irradiated on both sides in the short-axis direction of the opening 2360 of the short-axis side light shielding portion 236 have a major axis direction of L1 = 28 mm and a minor axis direction of d S1 ≒ 86 μm, which is substantially linear. Further, since the long-axis side light shielding portion 235 is disposed at the rear focal position of the third lens 233, the irradiation regions 82 (see FIG. 6) of the first-order diffracted light irradiated on both sides in the long-axis direction of the opening 2350 of the long-axis side light shielding portion 235 have a major axis direction of d L3 ≒ 18 μm and a minor axis direction of L3 = 4 mm, which is substantially linear.

[0081] On the other hand, assuming an optical device (hereinafter referred to as the "optical device of the comparative example") in which the modulation beam L33 is condensed at the same position on the optical path (i.e., the rear focal position of the convex lens) by one convex lens in both the major axis direction and the minor axis direction, the first-order diffracted light is irradiated on a dot-shaped irradiation region on the light shielding portion disposed at the rear focal position. For example, when the focal length of the convex lens is 240 mm, the diameter of the irradiation region of the first-order diffracted light on the light shielding portion is about 326 μm.

[0082] Therefore, in the optical device 12 according to the present embodiment, the power density of the first-order diffracted light on the short-axis side light shielding portion 236 and the power density of the first-order diffracted light on the long-axis side light shielding portion 235 are reduced to 10% or less of the power density of the first-order diffracted light on the light shielding portion of the optical device of the comparative example.

[0083] The sizes of the first galvanometer mirror 371 and the second galvanometer mirror 372 are changed according to the positions of the first galvanometer mirror 371 and the second galvanometer mirror 372. For example, the first galvanometer mirror 371 is arranged 20 mm in front of the long-axis side light-shielding portion 235 (i.e., on the light modulator 22 side in the optical axis direction), and the second galvanometer mirror 372 is arranged 20 mm behind the long-axis side light-shielding portion 235 (i.e., on the scanned surface 92 side in the optical axis direction). In this case, the irradiation region of the modulation beam L33 on the long-axis side light-shielding portion 235 is, as described above, substantially linear with a length of 22 μm in the long-axis direction and a width of 4 mm in the short-axis direction, and the NA forming the modulation beam L33 is approximately 0.058 on the long-axis side and substantially 0 on the short-axis side. Therefore, the irradiation region of the modulation beam L33 on the first galvanometer mirror 371 and the second galvanometer mirror 372 is substantially rectangular with a length of approximately 2.3 mm in the long-axis direction and a width of approximately 4 mm in the short-axis direction. Accordingly, the sizes of the first galvanometer mirror 371 and the second galvanometer mirror 372 are set to be equal to or larger than the size that can accommodate the irradiation region.

[0084] Next, the optical device 12a according to the second embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIGS. 7 and 8 are diagrams schematically showing the optical paths of the laser beam L31, the shaped beam L32, and the modulation beam L33 in the optical device 12a, and correspond to FIGS. 3 and 4 described above.

[0085] In the optical device 12a shown in FIGS. 7 and 8, instead of the first optical system 21 and the second optical system 23 shown in FIGS. 3 and 4, a first optical system 21a and a second optical system 23a having a configuration different from that of the first optical system 21 and the second optical system 23 are provided. Specifically, the first optical system 21a includes an illumination optical element 216a instead of the beam expander 216 (that is, the cylindrical lens 214a, the cylindrical lens 215a, the cylindrical lens 214b, and the cylindrical lens 215b) shown in FIGS. 3 and 4. The second optical system 23a includes a first lens 231a, a second lens 232a, and a third lens 233a instead of the first lens 231, the second lens 232, the third lens 233, and the fourth lens 234 shown in FIGS. 3 and 4. Other configurations of the optical device 12a are substantially the same as those of the optical device 12, and in the following description, the corresponding configurations of the optical device 12 are denoted by the same reference numerals.

[0086] Similar to the first optical system 21 described above, the first optical system 21a shapes the laser beam L31 emitted from the laser light source 11 into a substantially rectangular shaped beam L32 that is long in the major axis direction and guides it to the optical modulator 22. In the first optical system 21a, the collimating lens 211, the beam shaper 213, and the illumination optical element 216a are arranged in this order in the traveling direction of the light (i.e., the optical axis direction) from the laser light source 11 to the optical modulator 22. The illumination optical element 216a is, for example, a single lens, and in the examples shown in FIGS. 7 and 8, it is a single spherical convex lens. The illumination optical element 216a may be an aspherical convex lens. Further, the illumination optical element 216a may be composed of a plurality of optical elements.

[0087] In the first optical system 21a illustrated in FIGS. 7 and 8, no optical element other than the illumination optical element 216a, which is a single lens, is arranged between the beam shaper 213 and the optical modulator 22. In other words, the beam emitted from the beam shaper 213 directly (i.e., without passing through other optical elements) enters the illumination optical element 216a. Further, the shaped beam L32 that has passed through the illumination optical element 216a directly (i.e., without passing through other optical elements) enters the optical modulator 22.

[0088] In the first optical system 21a, in substantially the same manner as the first optical system 21, the laser beam L31 emitted from the laser light source 11 becomes a collimated beam that is parallel light in the major axis direction and the minor axis direction by passing through the collimating lens 211. The collimated beam passes through the beam shaper 213 and the illumination optical element 216a and is guided to the optical modulator 22. The intensity distribution of the collimated beam before entering the beam shaper 213 is a Gaussian distribution in the major axis direction and also a Gaussian distribution in the minor axis direction, as shown by being surrounded by a rectangular frame on the lower side of the optical path diagrams in FIGS. 7 and 8.

[0089] The beam shaper 213 spreads the collimated beam (i.e., the incident light) entering the beam shaper 213 at different divergence angles in the major axis direction and the minor axis direction. The intensity distribution of the collimated beam in the major axis direction and the minor axis direction is converted from a Gaussian distribution to a top-hat distribution (also called a rectangular distribution) by passing through the beam shaper 213. Also, the intensity distribution of the collimated beam in the major axis direction and the minor axis direction is maintained as a top-hat distribution when passing through the illumination optical element 216a. Therefore, as shown by being surrounded by a rectangular frame on the lower side of the optical path diagrams in FIGS. 7 and 8, the intensity distribution of the shaped beam L32 incident on the optical modulator 22 after passing through the first optical system 21a (i.e., the intensity distribution of the shaped beam L32 on the modulation surface of the optical modulator 22) is a top-hat distribution in each of the major axis direction and the minor axis direction.

[0090] In the first optical system 21a, the above-mentioned collimated beam passes through the beam shaper 213 and the illumination optical element 216a, and becomes a shaped beam L32 that is parallel light in the major axis direction and convergent light in the minor axis direction, and is incident on the modulation surface of the optical modulator 22. The converging position of the shaped beam L32 in the minor axis direction by the illumination optical element 216a is located on the side opposite to the first optical system 21a across the optical modulator 22 (i.e., the scanned surface 92 side of the optical modulator 22). For this reason, the shaped beam L32 is incident on the optical modulator 22 before reaching the converging position on the minor axis side.

[0091] The shaped beam L32 incident on the optical modulator 22 is modulated by the optical modulator 22 and enters the second optical system 23a as a modulated beam L33. The modulated beam L33 incident on the second optical system 23a from the optical modulator 22 is parallel light in the major axis direction and convergent light in the minor axis direction. The optical modulator 22 is, for example, an LPLV.

[0092] The second optical system 23a is an optical system incorporating a scanning mechanism 237 that scans the modulated beam L33 on the scanned surface 92 inside a projection optical system that guides the modulated beam L33 from the optical modulator 22 to the scanned surface 92 of the shaping material 91, substantially the same as the above-described second optical system 23. The second optical system 23a includes a first lens 231a, a second lens 232a, a third lens 233a, a major-axis-side light-shielding portion 235, a minor-axis-side light-shielding portion 236, and a scanning mechanism 237.

[0093] The first lens 231a is, for example, a single lens, and in the examples shown in FIGS. 7 and 8, it is a single spherical convex lens. The second lens 232a is, for example, a single lens, and in the examples shown in FIGS. 7 and 8, it is a single spherical convex lens. The first lens 231a and the second lens 232a may each be an aspherical convex lens. The third lens 233a is, for example, a single lens, and in the examples shown in FIGS. 7 and 8, it is a single cylindrical convex lens.

[0094] Also in this embodiment, as described above, the scanning mechanism 237 is a galvanometer scanner. In the scanning mechanism 237, the first galvanometer mirror 371 is rotated by a first galvanometer motor (not shown), thereby changing the reflection direction of the modulated beam L33 by the first galvanometer mirror 371. Also, the second galvanometer mirror 372 is rotated by a second galvanometer motor (not shown), thereby changing the reflection direction of the modulated beam L33 by the second galvanometer mirror 372.

[0095] In the second optical system 23a illustrated in FIGS. 7 and 8, on the optical axis from the optical modulator 22 toward the surface 92 to be scanned, the short-axis side light-shielding portion 236, the third lens 233a, the first lens 231a, the long-axis side light-shielding portion 235, and the second lens 232a are arranged in this order.

[0096] The short-axis side light-shielding portion 236 is disposed near the condensing position on the short-axis side of the modulation beam L33 between the optical modulator 22 and the third lens 233a, in the same manner as the second optical system 23 described above. In the second optical system 23a illustrated in FIGS. 7 and 8, no other optical elements such as lenses are disposed between the optical modulator 22 and the short-axis side light-shielding portion 236. In other words, the modulation beam L33 modulated by the optical modulator 22 directly (that is, without passing through other optical elements) enters the short-axis side light-shielding portion 236. Further, the modulation beam L33 that has passed through the aperture 2360 of the short-axis side light-shielding portion 236 directly (that is, without passing through other optical elements) enters the third lens 233.

[0097] The long-axis side light-shielding portion 235 is disposed near the condensing position on the long-axis side of the modulation beam L33 between the first lens 231a and the second lens 232a, in the same manner as the second optical system 23 described above. The position where the long-axis side light-shielding portion 235 is disposed is, for example, near the rear focal position of the first lens 231a. The rear focal position of the first lens 231a coincides with the front focal position of the second lens 232a.

[0098] In the second optical system 23a, further, a scanning mechanism 237 is disposed between the first lens 231a and the second lens 232a on the optical axis. The scanning mechanism 237 is disposed in the vicinity of the long-axis side light-shielding portion 235 adjacent to the long-axis side light-shielding portion 235, in the same manner as the second optical system 23 described above. In the optical axis direction, the distance between the scanning mechanism 237 and the long-axis side light-shielding portion 235 is smaller than the distance between the scanning mechanism 237 and the first lens 231a and the distance between the scanning mechanism 237 and the second lens 232a.

[0099] Specifically, the first galvanometer mirror 371 of the scanning mechanism 237 is disposed on the side of the modulator 22 of the long-axis side light shielding portion 235 in the optical axis direction. In other words, the first galvanometer mirror 371 is positioned between the first lens 231a and the long-axis side light shielding portion 235 on the optical axis. In the optical axis direction, the distance between the first galvanometer mirror 371 and the long-axis side light shielding portion 235 is smaller than the distance between the first galvanometer mirror 371 and the first lens 231a. The second galvanometer mirror 372 is disposed on the side of the surface 92 to be scanned of the long-axis side light shielding portion 235 in the optical axis direction. In other words, the second galvanometer mirror 372 is positioned between the long-axis side light shielding portion 235 and the second lens 232a on the optical axis. In the optical axis direction, the distance between the second galvanometer mirror 372 and the long-axis side light shielding portion 235 is smaller than the distance between the second galvanometer mirror 372 and the second lens 232a. The positional relationship between the first galvanometer mirror 371 and the second galvanometer mirror 372 and the long-axis side light shielding portion 235 etc. is substantially the same as that in the second optical system 23 described above.

[0100] In the second optical system 23a illustrated in FIGS. 7 and 8, it is preferable that no optical elements other than those illustrated are provided. For example, between the first lens 231a and the second lens 232a on the optical axis, no optical elements other than the long-axis side light shielding portion 235 and the scanning mechanism 237 are arranged. Naturally, no other optical elements are arranged between the first lens 231a and the first galvanometer mirror 371, and between the first galvanometer mirror 371 and the long-axis side light shielding portion 235. Therefore, the modulated beam L33 that has passed through the first lens 231a is incident directly (i.e., without passing through other optical elements) on the first galvanometer mirror 371, and the modulated beam L33 reflected by the first galvanometer mirror 371 is incident directly (i.e., without passing through other optical elements) on the long-axis side light shielding portion 235.

[0101] Also, no other optical elements are arranged between the long-axis side light shielding portion 235 and the second galvanometer mirror 372, and between the second galvanometer mirror 372 and the second lens 232a. Therefore, the modulated beam L33 that has passed through the long-axis side light shielding portion 235 is directly incident on the second galvanometer mirror 372 (i.e., without passing through other optical elements), and the modulated beam L33 reflected by the second galvanometer mirror 372 is directly incident on the second lens 232a (i.e., without passing through other optical elements).

[0102] In the second optical system 23a, the modulation surface of the optical modulator 22 and the scanned surface 92 of the shaping material 91 are optically conjugated in the long-axis direction by the first lens 231a and the second lens 232a. Also, in the short-axis direction, the short-axis side light shielding portion 236 and the scanned surface 92 are optically conjugated by the third lens 233a, the first lens 231a, and the second lens 232a. Note that in the second optical system 23a, the types of the first lens 231a, the second lens 232a, and the third lens 233a may be variously changed, and optical elements other than those described above may be added.

[0103] Similar to the second optical system 23, the second optical system 23a guides the modulated beam L33 from the optical modulator 22 to the scanned surface 92 of the shaping material 91, forms a spot light array on the scanned surface 92, and scans the spot light array on the scanned surface 92.

[0104] Specifically, the modulation beam L33 with the convergent light on the short-axis side is converged on the short-axis side at the condensing position where the short-axis side light shielding portion 236 is disposed, and passes through the opening 2360 of the short-axis side light shielding portion 236. Specifically, among the modulation beam L33 which is the reflected light reflected by the optical modulator 22, the 0th order light and the non-0th order diffracted light on the long-axis side pass through the opening 2360 of the short-axis side light shielding portion 236. The cross-sectional shape of the modulation beam L33 passing through the opening 2360 of the short-axis side light shielding portion 236 is substantially linear or substantially rectangular, being long in the long-axis direction. The intensity distribution of the modulation beam L33 passing through the opening 2360 of the short-axis side light shielding portion 236 is a substantially top-hat distribution in the long-axis direction and a squared sinc function distribution in the short-axis direction, as shown by being surrounded by a rectangular frame on the lower side of the optical path diagrams in FIGS. 7 and 8.

[0105] On the other hand, among the modulation beam L33, the non-0th order diffracted light on the short-axis side is blocked by the short-axis side light shielding portion 236. The non-0th order diffracted light on the short-axis side is irradiated onto an irradiation region 81 which is substantially linear or substantially rectangular, being long in the long-axis direction, at positions above and below (i.e., on both sides in the short-axis direction of the opening 2360) the opening 2360 of the short-axis side light shielding portion 236 shown in FIG. 5.

[0106] As shown in FIGS. 7 and 8, the cross-section of the modulation beam L33 passing through the opening 2360 of the short-axis side light shielding portion 236 spreads in the short-axis direction as it moves away from the short-axis side light shielding portion 236 in the optical axis direction. The modulation beam L33 passing through the short-axis side light shielding portion 236 becomes parallel light in the short-axis direction by passing through the third lens 233a and the first lens 231a. For example, the modulation beam L33 passing through the short-axis side light shielding portion 236 becomes parallel light in the short-axis direction by passing through the third lens 233a and does not refract in the short-axis direction when passing through the first lens 231a. Also, in the long-axis direction, the modulation beam L33 does not refract when passing through the third lens 233a, and is converged by passing through the first lens 231a and is condensed at the rear focal position of the first lens 231a (i.e., the front focal position of the second lens 232a).

[0107] The modulated beam L33 that has passed through the third lens 233a and the first lens 231a is incident on the first galvanometer mirror 371 of the scanning mechanism 237. Specifically, among the modulated beam L33, the zero-order light is incident on the first galvanometer mirror 371, and the non-zero-order diffracted light on the major axis side (mainly the first-order diffracted light) is not incident on the first galvanometer mirror 371. The zero-order light of the modulated beam L33 reflected by the first galvanometer mirror 371 passes through the aperture 2350 of the major-axis-side light-shielding portion 235. In the scanning mechanism 237, when the first galvanometer mirror 371 is rotated by the first galvanometer motor, the reflection direction of the zero-order light by the first galvanometer mirror 371 in the minor-axis direction is changed. As a result, at the major-axis-side light-shielding portion 235 arranged at the condensing position on the major axis side of the modulated beam L33, the position of the zero-order light passing through the aperture 2350 in the minor-axis direction is changed.

[0108] On the other hand, the non-zero-order diffracted light on the major axis side of the modulated beam L33 is not incident on the first galvanometer mirror 371 as described above, and is directly incident on and blocked by the major-axis-side light-shielding portion 235. The non-zero-order diffracted light on the major axis side is irradiated onto a substantially linear irradiation region 82 extending in the minor-axis direction at portions on the left and right sides (i.e., both sides in the major-axis direction of the aperture 2350) in the figure, which are outside the aperture 2350 of the major-axis-side light-shielding portion 235 shown in FIG. 6.

[0109] The cross-sectional shape of the modulated beam L33 passing through the aperture 2350 of the major-axis-side light-shielding portion 235 is substantially linear or substantially rectangular, being long in the minor-axis direction. The intensity distribution of the modulated beam L33 passing through the aperture 2350 of the major-axis-side light-shielding portion 235 is a squared distribution of the sinc function in the major-axis direction and a top-hat distribution in the minor-axis direction, as shown enclosed by a rectangular frame on the lower side of the optical path diagrams in FIGS. 7 and 8.

[0110] The cross-section of the modulated beam L33 (i.e., the zero-order light) passing through the aperture 2350 of the long-axis side light-shielding portion 235 spreads in the long-axis direction as it moves away from the long-axis side light-shielding portion 235 in the optical axis direction. The modulated beam L33 passing through the aperture 2350 of the long-axis side light-shielding portion 235 is incident on the second galvanometer mirror 372 of the scanning mechanism 237. The modulated beam L33 reflected by the second galvanometer mirror 372 is incident on the second lens 232a. In the scanning mechanism 237, the second galvanometer mirror 372 is rotated by the second galvanometer motor, thereby changing the reflection direction of the modulated beam L33 in the long-axis direction by the second galvanometer mirror 372. As a result, the position of the modulated beam L33 in the long-axis direction incident on the second lens 232a is changed.

[0111] The modulated beam L33 passes through the second lens 232a and becomes parallel light in the long-axis direction and is incident on the scanned surface 92 of the shaping material 91. Also, the modulated beam L33 incident on the second lens 232a as parallel light in the short-axis direction passes through the second lens 232a and is focused in the short-axis direction on the scanned surface 92 located at the rear focal position of the second lens 232a.

[0112] The cross-sectional shape of the modulated beam L33 on the scanned surface 92 of the shaping material 91 is a substantially rectangular shape that is long in the long-axis direction. The intensity distribution of the modulated beam L33 on the scanned surface 92 is a top-hat distribution in the long-axis direction and a squared sinc function distribution in the short-axis direction, as shown by being surrounded by a rectangular frame on the lower side of the optical path diagrams in FIGS. 7 and 8. In other words, the intensity distribution of the spot light array formed on the scanned surface 92 by the modulated beam L33 in the long-axis direction and the intensity distribution in the short-axis direction are a top-hat distribution and a squared sinc function distribution, respectively. Thereby, the modulated beam L33 can be suitably focused on the scanned surface 92.

[0113] In the three-dimensional shaping apparatus 1 provided with the optical device 12a, similarly to the above, in the scanning mechanism 237 of the optical device 12a, when the first galvanometer mirror 371 rotates, the above-described spot light array is scanned on the scanned surface 92 of the shaping material 91 in the direction corresponding to the minor axis direction (that is, the direction perpendicular to the arrangement direction of the plurality of spot lights in the spot light array). Further, when the second galvanometer mirror 372 rotates in the scanning mechanism 237, the above-described spot light array is scanned on the scanned surface 92 of the shaping material 91 in the direction corresponding to the major axis direction (that is, the direction parallel to the arrangement direction of the plurality of spot lights in the spot light array). In the three-dimensional shaping apparatus 1, by repeating the scanning of the spot light array on the shaping material 91 and the supply of the shaping material 91 to the shaping space 140, a three-dimensional shaped object is formed.

[0114] In the above-described optical devices 12 and 12a, when an optical element that is disposed between the short-axis side light-shielding portion 236 and the scanned surface 92 of the shaping material 91 and condenses the modulation beam L33 in the major axis direction is called a "first projection optical element", in the optical device 12, the third lens 233 is the first projection optical element, and in the optical device 12a, the first lens 231a is the first projection optical element. Further, when an optical element that is disposed between the long-axis side light-shielding portion 235 and the scanned surface 92 and converges the modulation beam L33 that has passed through the long-axis side light-shielding portion 235 in the minor axis direction and condenses it on the scanned surface 92 is called a "second projection optical element", in the optical device 12, the fourth lens 234 is the second projection optical element, and in the optical device 12a, the second lens 232a is the second projection optical element.

[0115] In the above-described optical devices 12 and 12a, when the first galvanometer mirror 371 rotates, the reflection direction of the modulation beam L33 in the minor axis direction is changed, and when the second galvanometer mirror 372 rotates, the reflection direction of the modulation beam L33 in the major axis direction is changed. However, the present invention is not limited to this. For example, when the first galvanometer mirror 371 rotates, the reflection direction of the modulation beam L33 in the major axis direction may be changed, and when the second galvanometer mirror 372 rotates, the reflection direction of the modulation beam L33 in the minor axis direction may be changed. That is, the first galvanometer mirror 371 changes the reflection direction of the modulation beam L33 in one of the major axis direction and the minor axis direction by rotating. Further, the second galvanometer mirror 372 changes the reflection direction of the modulation beam L33 in the other of the major axis direction and the minor axis direction by rotating.

[0116] In the above-described optical devices 12 and 12a, the first galvanometer mirror 371 is disposed between the first projection optical element (i.e., the third lens 233 / the first lens 231a) and the major-axis side light-shielding portion 235, and the second galvanometer mirror 372 is disposed between the major-axis side light-shielding portion 235 and the second projection optical element (i.e., the fourth lens 234 / the second lens 232a). However, the present invention is not limited to this. For example, the first galvanometer mirror 371 and the second galvanometer mirror 372 may be disposed between the major-axis side light-shielding portion 235 and the second projection optical element described above. In this case, since there is no mechanism for changing the direction of the modulation beam L33 on the light modulator 22 side of the major-axis side light-shielding portion 235 in the optical axis direction, the aperture 2350 of the major-axis side light-shielding portion 235 can be made smaller. Further, since the non-zero order diffracted light on the major-axis side does not enter the galvanometer mirror, the design of the scanning mechanism 237 and the major-axis side light-shielding portion 235 can be facilitated.

[0117] Alternatively, the first galvanometer mirror 371 and the second galvanometer mirror 372 may be disposed between the first projection optical element and the long-axis side light-shielding portion 235 described above. In this way, by disposing the first galvanometer mirror 371 and the second galvanometer mirror 372 on either one side of the long-axis side light-shielding portion 235 in the optical axis direction, the distance between the first galvanometer mirror 371 and the second galvanometer mirror 372 in the optical axis direction can be reduced. As a result, the second galvanometer mirror 372, which needs to receive the modulated beam L33 whose reflection direction has been changed by the first galvanometer mirror 371, can be miniaturized.

[0118] The arrangement of the first galvanometer mirror 371 and the second galvanometer mirror 372 is preferably determined such that the shape of the irradiation region of the modulated beam L33 on the scanned surface 92 of the shaping material 91 is close to a desired shape, taking into account the distortion characteristics due to the arrangement and the distortion characteristics of the second projection optical element described above.

[0119] In the optical devices 12, 12a, the scanning mechanism 237 may include only one of the first galvanometer mirror 371 and the second galvanometer mirror 372. The one galvanometer mirror may be disposed on the light modulator 22 side of the long-axis side light-shielding portion 235 in the optical axis direction, or may be disposed on the scanned surface 92 side of the long-axis side light-shielding portion 235. Further, the reflection direction of the modulated beam L33 changed by the rotation of the one galvanometer mirror may be in the long-axis direction or in the short-axis direction.

[0120] That is, when the one galvanometer mirror is disposed on the modulator 22 side of the long-axis side light shielding portion 235 in the optical axis direction, the modulation beam L33 before entering the long-axis side light shielding portion 235 is scanned in one of the long-axis direction and the short-axis direction as the one galvanometer mirror rotates. Further, when the one galvanometer mirror is disposed on the scanned surface 92 side of the long-axis side light shielding portion 235 in the optical axis direction, the modulation beam L33 that has passed through the long-axis side light shielding portion 235 is scanned in one of the long-axis direction and the short-axis direction as the one galvanometer mirror rotates. Then, the scanning of the modulation beam L33 in the other direction of the long-axis direction and the short-axis direction is realized, for example, by moving the shaping material 91 in the shaping space 140 in the direction corresponding to the other direction by a moving mechanism such as a linear motor provided in the material supply mechanism 14.

[0121] As described above, the optical devices 12, 12a are devices that irradiate and scan a spot light array on an object (in the above example, the shaping material 91). The optical devices 12, 12a include a first optical system 21, 21a, a modulator 22, and a second optical system 23, 23a. The first optical system 21, 21a shapes the laser beam L31 into a shaped beam L32 that is long in the long-axis direction. The modulator 22 modulates the shaped beam L32 to form a modulation beam L33 having a pattern in the long-axis direction. The second optical system 23, 23a guides the modulation beam L33 to the scanned surface 92 of the object to form a spot light array extending in the long-axis direction on the scanned surface 92 and scans the spot light array on the scanned surface 92.

[0122] The second optical system 23, 23a includes a short-axis side light shielding portion 236, a first projection optical element (in the above example, the third lens 233 or the first lens 231a), a long-axis side light shielding portion 235, a second projection optical element (in the above example, the fourth lens 234 or the second lens 232a), and a scanning mechanism 237.

[0123] The short-axis side light shielding part 236 is arranged at the condensing position on the short-axis side of the modulation beam L33. The short-axis side light shielding part 236 blocks the non-zero order diffracted light on the short-axis side of the modulation beam L33. The first projection optical element is arranged between the short-axis side light shielding part 236 and the surface 92 to be scanned. The first projection optical element condenses the modulation beam L33 in the long-axis direction. The long-axis side light shielding part 235 is arranged at the condensing position on the long-axis side of the modulation beam L33 by the first projection optical element between the first projection optical element and the surface 92 to be scanned. The long-axis side light shielding part 235 blocks the non-zero order diffracted light on the long-axis side of the modulation beam L33. The second projection optical element is arranged between the long-axis side light shielding part 235 and the surface 92 to be scanned. The second projection optical element converges the modulation beam L33 that has passed through the long-axis side light shielding part 235 in the short-axis direction and condenses it on the surface 92 to be scanned, thereby forming a spot light array on the surface 92 to be scanned.

[0124] The scanning mechanism 237 is arranged adjacent to the long-axis side light shielding part 235 between the first projection optical element and the second projection optical element. The scanning mechanism 237 scans the modulation beam L33 incident on the long-axis side light shielding part 235 or the modulation beam L33 that has passed through the long-axis side light shielding part 235 in at least one of the long-axis direction and the short-axis direction. In the optical devices 12, 12a, the modulation surface of the light modulator 22 and the surface 92 to be scanned are optically conjugated in the long-axis direction by the second optical systems 23, 23a.

[0125] As described above, in the second optical systems 23, 23a of the optical devices 12, 12a, a scanning mechanism 237 for scanning the spot light array on the surface 92 to be scanned is incorporated inside the projection optical system that relays the modulation beam L33 from the light modulator 22 to the object and forms a spot light array on the surface 92 to be scanned. For this reason, optical elements other than the scanning mechanism required in the scanning unit (for example, a collimating lens and an Fθ lens provided before and after the galvanometer scanner in the scanning unit) can be omitted when the projection optical system and the scanning unit are provided separately. As a result, the structure of the optical devices 12, 12a can be simplified. In addition, the optical devices 12, 12a can be miniaturized. Furthermore, the manufacturing cost of the optical devices 12, 12a can also be reduced.

[0126] As described above, the scanning mechanism 237 is preferably a galvanometer scanner that changes the reflection direction of the modulated beam L33. Thereby, scanning of the spot light array on the surface 92 to be scanned can be realized with a simple structure. As a result, the structure of the optical devices 12, 12a can be further simplified.

[0127] As described above, the galvanometer scanner preferably includes a first galvanometer mirror 371 and a second galvanometer mirror 372. The first galvanometer mirror 371 is preferably disposed adjacent to the long-axis side light-shielding portion 235 between the first projection optical element and the long-axis side light-shielding portion 235. The first galvanometer mirror 371 changes the reflection direction of the modulated beam L33 in one of the long-axis direction and the short-axis direction by rotating. Further, the second galvanometer mirror 372 is preferably disposed adjacent to the long-axis side light-shielding portion 235 between the long-axis side light-shielding portion 235 and the second projection optical element. The second galvanometer mirror 372 changes the reflection direction of the modulated beam L33 in the other of the long-axis direction and the short-axis direction by rotating.

[0128] In this way, by arranging the first galvanometer mirror 371 and the second galvanometer mirror 372 on both the front and rear sides of the long-axis side light-shielding portion 235 in the optical axis direction, the distance between the first projection optical element and the long-axis side light-shielding portion 235 and the distance between the long-axis side light-shielding portion 235 and the second projection optical element can be made substantially the same. That is, in the optical axis direction, the distance between the condensing position on the long-axis side of the modulated beam L33 and the first projection optical element and the distance between the condensing position on the long-axis side of the modulated beam L33 and the second projection optical element can be made substantially the same. Thereby, the distortion characteristics of the optical devices 12, 12a can be improved.

[0129] As described above, it is preferable that the first galvanometer mirror 371 changes the reflection direction in the minor axis direction of the modulation beam L33. As a result, in the long-axis side light shielding portion 235, the width in the long-axis direction of the opening 2350 (that is, the width in the left-right direction in FIG. 6) can be reduced. As a result, it is possible to suppress non-zero order diffracted light on the long-axis side from entering the opening 2350, and the modulation of the spot light array by the optical modulator 22 can be performed with high accuracy.

[0130] As described above, it is preferable that the first optical systems 21, 21a include a beam shaper 213. The beam shaper 213 preferably converts the intensity distribution in the long-axis direction of the laser beam L31 from a Gaussian distribution so that the intensity distribution in the long-axis direction of the shaped beam L32 on the modulation surface is a top-hat distribution. Thereby, it is possible to increase the total input light amount while reducing the maximum power density of the shaped beam L32 incident on the optical modulator 22. Therefore, it is possible to increase the amount of light input to the optical modulator 22 while reducing the risk of damage to the optical modulator 22. As a result, the power density of the modulation beam L33 irradiated to the object can be suitably increased.

[0131] As described above, the beam shaper 213 preferably converts the intensity distribution in the minor axis direction of the laser beam L31 from a Gaussian distribution so that the intensity distribution in the minor axis direction of the shaped beam L32 on the modulation surface is also a top-hat distribution. Thereby, it is possible to further increase the total input light amount while further reducing the maximum power density of the shaped beam L32 incident on the optical modulator 22.

[0132] As described above, it is preferable that no optical element is disposed between the scanning mechanism 237 and the long-axis side light shielding portion 235. Thereby, the structure of the optical apparatuses 12, 12a can be further simplified.

[0133] As described above, it is preferable that the optical modulator 22 is a PLV. Since the PLV has high power resistance performance, it is particularly suitable for the optical modulator 22 for which an increase in the input light amount is required.

[0134] The above-described three-dimensional shaping apparatus 1 includes optical devices 12, 12a, a laser light source 11, and a material holding unit (in the above example, the shaping unit 141). The laser light source 11 emits a laser beam L31 toward the optical devices 12, 12a. The material holding unit holds the shaping material 91, which is the object irradiated with the modulated beam L33 from the optical devices 12, 12a. In the three-dimensional shaping apparatus 1, as described above, the structure of the optical devices 12, 12a can be simplified. Therefore, the structure of the three-dimensional shaping apparatus 1 can be simplified and downsized.

[0135] In the above-described optical devices 12, 12a and three-dimensional shaping apparatus 1, various modifications are possible.

[0136] For example, the optical modulator 22 is not necessarily limited to LPLV, and may be a PLV other than LPLV. Also, as the optical modulator 22, those other than PLV, such as GLV (Grating Light Valve) (registered trademark) and DMD (Digital Micromirror Device), can also be used.

[0137] The scanning mechanism 237 does not necessarily have to be a galvanometer scanner, and may be, for example, a scanning mechanism having another structure such as a polygon laser scanner.

[0138] In the optical devices 12, 12a, the beam shaper 213 does not necessarily have to be a single optical element, and may be composed of a plurality of optical elements. The beam shaper 213 may convert only the intensity distribution in the major axis direction of the laser beam L31 into a top-hat distribution without converting the intensity distribution in the minor axis direction of the laser beam L31 into a top-hat distribution. Alternatively, in the optical devices 12, 12a, the beam shaper 213 that converts the intensity distribution of the laser beam L31 into a top-hat distribution may be omitted.

[0139] In the optical devices 12, 12a, other optical elements may be arranged between the scanning mechanism 237 and the major-axis side light-shielding part 235.

[0140] The optical devices 12, 12a may be provided in a three-dimensional shaping device having a structure different from that of the above-described three-dimensional shaping device 1. Further, the optical devices 12, 12a do not necessarily have to be provided in the three-dimensional shaping device 1 and may be used in various devices other than the three-dimensional shaping device (for example, a laser processing machine such as a laser marking device or a laser drilling device).

[0141] The configurations in the above-described embodiments and each modification example may be appropriately combined as long as they do not contradict each other.

Explanation of Reference Numerals

[0142] 1 Three-dimensional shaping device 11 Laser light source 12, 12a Optical device 21, 21a First optical system 22 Optical modulator 23, 23a Second optical system 91 Shaping material 92 Scanned surface 141 Shaping unit 213 Beam shaper 231, 231a First lens 232, 232a Second lens 233, 233a Third lens 234 Fourth lens 235 Long-axis side light-shielding part 236 Short-axis side light-shielding part 237 Scanning mechanism 371 First galvanometer mirror 372 Second galvanometer mirror L31 Laser light L32 Shaped beam L33 Modulated beam

Claims

1. An optical device that irradiates and scans a spot light array on an object, comprising: a first optical system that shapes a laser beam into a shaped beam that is long in the major axis direction; an optical modulator that modulates the shaped beam to form a modulated beam having a pattern in the major axis direction; a second optical system that guides the modulated beam to a scanned surface of the object to form a spot light array extending in the major axis direction on the scanned surface and scans the spot light array on the scanned surface; and the second optical system includes: a short-axis side light shielding portion that is disposed at a condensing position on the short-axis side of the modulated beam and blocks non-zero order diffracted light on the short-axis side of the modulated beam; a first projection optical element that is disposed between the short-axis side light shielding portion and the scanned surface and condenses the modulated beam in the major axis direction; a long-axis side light shielding portion that is disposed at a condensing position on the long-axis side of the modulated beam by the first projection optical element between the first projection optical element and the scanned surface and blocks non-zero order diffracted light on the long-axis side of the modulated beam; a second projection optical element that is disposed between the long-axis side light shielding portion and the scanned surface, converges the modulated beam that has passed through the long-axis side light shielding portion in the short-axis direction, and condenses it on the scanned surface to form a spot light array on the scanned surface; a scanning mechanism that is disposed adjacent to the long-axis side light shielding portion between the first projection optical element and the second projection optical element and scans the modulated beam incident on the long-axis side light shielding portion or the modulated beam that has passed through the long-axis side light shielding portion in at least one of the major axis direction and the short-axis direction; and an optical device in which the modulated surface of the optical modulator and the scanned surface are optically conjugated in the major axis direction by the second optical system.

2. The optical device according to claim 1, wherein the scanning mechanism is a galvanometer scanner that changes the reflection direction of the modulated beam.

3. The optical device according to claim 2, wherein the galvanometer scanner includes: a first galvanometer mirror that is disposed adjacent to the long-axis side light shielding portion between the first projection optical element and the long-axis side light shielding portion and changes the reflection direction of the modulated beam in one of the major axis direction and the short-axis direction by rotating. A second galvanometer mirror that is disposed adjacent to the long-axis side light-shielding part between the long-axis side light-shielding part and the second projection optical element and that changes the reflection direction of the modulation beam in the other direction of the long-axis direction and the short-axis direction by rotating. An optical device comprising the same.

4. The optical device according to claim 3, wherein the first galvanometer mirror is an optical device that changes the reflection direction of the modulation beam in the short-axis direction.

5. The optical device according to claim 1, wherein the first optical system includes a beam shaper that converts the intensity distribution of the laser beam in the long-axis direction from a Gaussian distribution so that the intensity distribution of the shaped beam on the modulation surface in the long-axis direction is a top-hat distribution.

6. The optical device according to claim 5, wherein the beam shaper is an optical device that also converts the intensity distribution of the laser beam in the short-axis direction from a Gaussian distribution so that the intensity distribution of the shaped beam on the modulation surface in the short-axis direction is a top-hat distribution.

7. The optical device according to claim 1, wherein no optical element is disposed between the scanning mechanism and the long-axis side light-shielding part.

8. The optical device according to claim 1, wherein the optical modulator is a PLV.

9. A three-dimensional shaping device, comprising the optical device according to any one of claims 1 to 8, a laser light source that emits the laser beam to the optical device, and a material holding part that holds a shaping material that is an object irradiated with the modulation beam from the optical device. A three-dimensional shaping device comprising the same.

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