WO2024062696A1

WO2024062696A1 - 3d molding device

Info

Publication number: WO2024062696A1
Application number: PCT/JP2023/021413
Authority: WO
Inventors: 博文水野; 大輔菱谷
Original assignee: 株式会社Ｓｃｒｅｅｎホールディングス
Priority date: 2022-09-21
Filing date: 2023-06-08
Publication date: 2024-03-28
Also published as: JP2024044353A

Abstract

This 3D molding device (1) comprises a laser light source (21), a diffractive optical modulator (23) having a plurality of modulating elements, a lighting optical system (22), a first projection optical system (241) forming an intermediate image of the optical modulator (23), a second projection optical system (242) for forming a projection image of the intermediate image on a projection surface (95) of a modeling material (91) constituting a processing region, and a layer forming mechanism (12). The second projection optical system (242) scans the projection image on the projection surface (95). The layer forming mechanism (12) forms a new material layer (92) on the projection surface (95) onto which the projection image was scanned to form a new projection surface (95). The projection magnification of the first projection optical system (241) is smaller than the projection magnification of the second projection optical system (242).

Description

3D modeling device

The present invention relates to a three-dimensional printing apparatus that forms a three-dimensional object using modulated light.
[Reference to Related Applications]
This application claims the benefit of priority from Japanese Patent Application JP2022-149838, filed on September 21, 2022, the entire disclosure of which is incorporated herein by reference.

In recent years, SLS (Selective Laser), which performs three-dimensional modeling by irradiating modulated laser light onto layers of building materials such as metal powder or resin powder to bond the building materials and repeating layer formation and bonding, has been developed. Sintering type three-dimensional printing device is used. For example, in Japanese Patent Publication No. 2021-509094 (Document 1), a flat beam is irradiated onto a diffraction grating light valve, and is then passed through a beam expander, a galvano scanner, and an Fθ lens to the surface of an object construction region. A three-dimensional modeling device that emits modulated light is disclosed.

Incidentally, in order to improve productivity in industrial three-dimensional printing apparatuses, it is required that the processing area, which is the area irradiated with light, be enlarged. In order to increase the size of the processing area, it is necessary to increase the distance (so-called working distance) between the lens that emits light toward the processing area and the processing area. A long working distance can be easily achieved by increasing the rear focal length of the magnifying optical system in a configuration in which the multi-spot line beam guided from the optical modulator is scanned and guided to the magnifying optical system. However, in such an optical system, the image of the multi-spot line beam on the processing area becomes large, making it difficult to obtain a large light intensity (so-called fluence) on the processing area. Therefore, low-speed scanning is required to ensure the exposure amount, which may reduce productivity. Moreover, the large size of the multi-spots on the processing area may reduce the shape accuracy of the modeled object.

The present invention is directed to a three-dimensional modeling device that utilizes a diffractive optical modulator, and an object of the present invention is to obtain a long working distance while suppressing a decrease in light intensity on a processing area. .

Aspect 1 of the present invention is a three-dimensional modeling apparatus, which includes a light source, a diffractive light modulator having a plurality of modulation elements, an illumination optical system that guides light from the light source to the light modulator, and a first projection optical system that forms an intermediate image of the light modulator at a predetermined intermediate position; a second projection optical system that forms a projection image of the intermediate image on a projection surface of the building material; and a layer of the building material. the second projection optical system includes a scanning mechanism that scans the projection image on the projection surface, and the layer formation mechanism includes a layer formation mechanism that scans the projection image on the projection surface. By forming a new layer of the modeling material thereon, a new projection surface is formed, and the projection magnification of the first projection optical system is smaller than the projection magnification of the second projection optical system.

According to the present invention, in a three-dimensional modeling apparatus that uses a diffractive optical modulator, a long working distance can be obtained while suppressing a decrease in light intensity on a processing area.

A second aspect of the present invention is the three-dimensional modeling apparatus according to the first aspect, in which the projection magnification of the first projection optical system is a reduction magnification, and the projection magnification of the second projection optical system is an enlargement magnification.

A third aspect of the present invention is the three-dimensional modeling apparatus according to the first aspect (or the first aspect or the second aspect), in which the light modulator is a diffraction grating light valve or a plane light valve.

Aspect 4 of the present invention is the three-dimensional modeling apparatus according to aspect 1 (which may be any one of aspects 1 to 3), in which the projection magnification of the first projection optical system is The total projection magnification by the optical system and the second projection optical system is 1/4 or more and 1/2 or less.

A fifth aspect of the present invention is the three-dimensional modeling apparatus according to the fourth aspect, wherein the light modulator is a diffraction grating light valve or a plane light valve, and the overall projection magnification is 1 or more and 2 or less.

Aspect 6 of the present invention is the three-dimensional printing apparatus according to any one of aspects 1 to 5, in which the layer forming mechanism is located between the second projection optical system and the projection surface on which the projection image is scanned. a layer forming member that moves along the projection plane.

The above objects and other objects, features, aspects and advantages will become apparent from the detailed description of the invention given below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of a three-dimensional printing device. FIG. 2 is a diagram showing a simplified structure of an optical modulator. FIG. 3 is a diagram showing a simplified projection optical system. FIG. 3 is a diagram for explaining how a projection plane of a material layer is irradiated with a multi-spot line beam. FIG. 3 is a diagram showing a projection optical system according to a comparative example.

FIG. 1 is a diagram showing the configuration of a three-dimensional printing apparatus 1 according to one embodiment of the present invention. The three-dimensional modeling device 1 is an SLS (Selective Laser Sintering) type device that performs three-dimensional modeling by irradiating modulated laser light onto a powder or paste-like modeling material and sintering or melting the modeling material. It is. Examples of the modeling material include metals, engineering plastics, ceramics, and synthetic resins. The modeling material may include multiple types of materials.

The three-dimensional modeling apparatus 1 includes an optical head 11 and a layer forming mechanism 12. The layer forming mechanism 12 forms a material layer 92 that is a thin layer of a modeling material 91 in the modeling space 30 . In FIG. 1, the layer forming mechanism 12 is shown in a longitudinal section, but parallel oblique lines indicating the cross section are partially omitted. In the modeling space 30, a plurality of material layers 92 are sequentially formed in a stacked manner. The optical head 11 irradiates modulated light onto the processing area on the surface of the material layer 92 .

The optical head 11 includes a laser light source 21, an illumination optical system 22, a light modulator 23, and a projection optical system 24. FIG. 1 shows a simplified structure of the optical head 11, and the arrangement of each component differs from the actual arrangement. The laser light source 21 may be provided outside the optical head 11 , and in this case, the light emitted from the laser light source 21 is guided into the optical head 11 . The projection optical system 24 includes a first projection optical system 241 and a second projection optical system 242. The second projection optical system 242 includes a pair of galvano scanners (not shown), and scans the light irradiation position on the material layer 92 two-dimensionally in the horizontal X and Y directions.

The layer forming mechanism 12 includes a shaping section 31 and a supply section 32. The modeling section 31 includes a first cylinder 311 and a first piston 312. The first cylinder 311 is a cylindrical member that extends in the vertical direction. The shape of the internal space of the first cylinder 311 in plan view is, for example, approximately rectangular. The first piston 312 is a substantially flat or columnar member accommodated in the internal space of the first cylinder 311, and has substantially the same shape as the internal space of the first cylinder 311 in plan view. The first piston 312 is movable in the vertical direction in the internal space of the first cylinder 311. In the modeling section 31, a three-dimensional space surrounded by the inner surface of the first cylinder 311 and the upper surface of the first piston 312 is the modeling space 30 in which three-dimensional modeling is performed.

The supply unit 32 includes a second cylinder 321, a second piston 322, and a layer forming member 323 that is a squeegee. The second cylinder 321 is a cylindrical member extending in the vertical direction, and is disposed adjacent to the side of the first cylinder 311 . The shape of the internal space of the second cylinder 321 in plan view is, for example, approximately rectangular. The second piston 322 is a substantially flat or columnar member accommodated in the internal space of the second cylinder 321, and has substantially the same shape as the internal space of the second cylinder 321 in plan view. The second piston 322 is movable in the vertical direction in the internal space of the second cylinder 321. In the supply section 32, a three-dimensional space surrounded by the inner surface of the second cylinder 321 and the upper surface of the second piston 322 is a storage space in which the modeling material 91 to be supplied to the modeling section 31 is stored. The layer forming member 323 is a rod-shaped (for example, substantially cylindrical) member that extends in the X direction across the upper opening of the second cylinder 321 . The layer forming member 323 is horizontally movable in the Y direction along the upper end surface of the second cylinder 321.

In the supply section 32, the second piston 322 rises by a predetermined distance, and the modeling material 91 in the second cylinder 321 is lifted upward. At this time, the surface of the modeling material 91 in the modeling space 30 is lowered by one material layer 92 in advance by the first piston 312 . As the layer forming member 323 moves from above the second cylinder 321 to above the first cylinder 311, the modeling material 91 that protrudes above the upper end surface of the second cylinder 321 enters the modeling space 30 of the modeling section 31. Supplied. The upper surface of the modeling material 91 held in the modeling space 30 is located at a predetermined height (for example, the same height as the upper end surface of the first cylinder 311). As a result, one material layer 92 is formed within the modeling space 30.

In the three-dimensional modeling apparatus 1, the modeling material 91 in the modeling space 30 is scanned with a multi-spot line beam 8, which is a projected image of an intermediate image of the optical modulator 23, which will be described later. As a result, the modeling materials are combined in a predetermined region of the projection plane 95, which is the surface of the modeling material 91 in the modeling space 30, that is, the surface of the latest material layer 92. As a result, a portion corresponding to one layer of the three-dimensional structure is formed. When the scanning of the multi-spot line beam 8 on the processing area, which is the projection plane 95, is completed, the first piston 312 descends by a distance corresponding to one material layer 92. Thereafter, by moving the layer forming member 323 along the projection surface 95 between the second projection optical system 242 and the projection surface 95, the modeling material 91 is supplied from the supply unit 32 to the modeling space 30, A new material layer 92 is formed on the projection surface 95 scanned by the multi-spot line beam 8. That is, a new projection surface 95 is formed. Then, the next scanning of the multi-spot line beam 8 is performed. In the three-dimensional modeling apparatus 1, a three-dimensional model 93 is formed in the modeling space 30 by repeating the formation of the material layer 92 in the modeling space 30 and the scanning of the multi-spot line beam 8 on the material layer 92. Ru.

In the three-dimensional modeling device 1, the optical head 11 and layer formation mechanism 12 are controlled by a control unit (not shown) based on design data (e.g., CAD data) of the three-dimensional object to be produced. The control unit is, for example, a normal computer equipped with a processor, memory, an input/output unit, and a bus. Note that the configuration of the control unit may be modified in various ways.

Next, details of the optical head 11 will be explained. Laser light source 21 emits laser light 81 to illumination optical system 22 . The laser light source 21 is, for example, a fiber laser light source. The wavelength of the laser beam 81 is, for example, 1.070 μm. Note that the type of laser light source 21 and the wavelength of laser light 81 may be variously changed.

The illumination optical system 22 shapes the beam cross section of the laser beam 81 into a substantially rectangular shaped beam 82 that is long in one direction (hereinafter referred to as the "long axis direction") and guides it to the optical modulator 23. In other words, the cross-sectional shape of the shaped beam 82 is a substantially rectangular shape that is long in the major axis direction and short in the minor axis direction perpendicular to the optical axis and the major axis direction. The cross-sectional shape of the shaped beam 82 is the shape of the shaped beam 82 in a plane perpendicular to the optical axis. The major axis direction and the minor axis direction are directions perpendicular to the direction of the optical axis, that is, the direction in which the shaped beam 82 travels. In the following explanation, light flux (including modulated light) is expressed as "light" or "beam", but the "cross section" of "light" or "beam" refers to the light flux in a plane perpendicular to the optical axis. means the cross section of The cross-sectional shape of the shaped beam 82 can also be considered to be a straight line extending in the major axis direction. The shape of the shaped beam 82 on the optical modulator 23 is, for example, a substantially rectangular shape with a length in the long axis direction of about 27 mm and a length in the short axis direction of about 1 mm.

The light modulator 23 converts the shaped beam 82 from the illumination optical system 22 into modulated light 83 that is one-dimensionally spatially modulated. As the optical modulator 23, for example, a PLV (Planar Light Valve) is used that can perform high-speed modulation and can withstand kW class laser light. Although the PLV is a two-dimensional spatial light modulator, the optical head 11 utilizes it as a one-dimensional spatial modulator.

FIG. 2 is a diagram showing a simplified structure of the optical modulator 23, which is a PLV. The optical modulator 23 includes a plurality of substantially rectangular pixels 231 arranged in a matrix (that is, two-dimensionally arranged) on a substrate (not shown). In the optical modulator 23, the surface of the plurality of pixels 231 becomes a modulation surface 234. In the example shown in FIG. 2, M pixels 231 are arranged in the vertical direction and N pixels 231 in the horizontal direction in the figure. The horizontal direction in FIG. 2 corresponds to the long axis direction of the shaping beam 82 (see FIG. 1), and the vertical direction in FIG. 2 corresponds to the short axis direction of the shaping beam 82.

Each pixel 231 is a modulation mechanism including a fixed member 232 and a movable member 233. The fixing member 232 is a planar, substantially rectangular member fixed to the substrate, and has a substantially circular opening in the center. The movable member 233 is a substantially circular member provided in the opening of the fixed member 232 . A fixed reflective surface is provided on the upper surface of the fixed member 232 (that is, the surface on the near side in the direction perpendicular to the paper plane in FIG. 2). A movable reflective surface is provided on the upper surface of the movable member 233. The movable member 233 is movable in a direction perpendicular to the plane of the paper in FIG.

In each pixel 231, by changing the relative position of the fixed member 232 and the movable member 233 in the direction perpendicular to the plane of the paper in FIG. (specularly reflected light) and non-zero-order diffracted light. In other words, in the pixel 231, light modulation using a diffraction grating is performed by moving the movable member 233 relative to the fixed member 232. The zero-order light emitted from the optical modulator 23 is guided to the modeling space 30 by the projection optical system 24 (see FIG. 1). Further, the non-zero-order diffracted light (mainly the first-order diffracted light) emitted from the optical modulator 23 is appropriately blocked and does not reach the modeling space 30 .

In the light modulator 23, the diffraction state of the reflected light from the M pixels 231 (hereinafter also referred to as "pixel row 230") arranged in a row in the vertical direction in FIG. 2 is the same. That is, when the reflected light from one pixel 231 is zero-order light, the reflection from all the other pixels 231 (that is, M-1 pixels 231) in the pixel row 230 that includes the one pixel 231 Light is also zero-order light. Furthermore, when the reflected light from one pixel 231 is non-zero-order diffracted light, the reflected light from all other pixels 231 in the pixel row 230 including the one pixel 231 is also non-zero-order diffracted light. That is, the optical modulator 23 does not perform modulation in the short axis direction of the shaped beam 82, but modulates it in the long axis direction. In this way, in the light modulator 23, the M pixels 231 of one pixel column 230 (that is, M modulation mechanisms) function as one modulation element corresponding to one unit space. The optical modulator 23 functions as a one-dimensional spatial light modulator including N modulation elements arranged in a row in the long axis direction of the shaped beam 82. In a preferred example, N is 1000 or more.

Next, the projection optical system 24 will be explained. As already explained, the projection optical system 24 includes the first projection optical system 241 and the second projection optical system 242. The first projection optical system 241 forms an intermediate image of the optical modulator 23 at a predetermined intermediate position. The second projection optical system 242 scans this intermediate image and projects it onto the material layer 92, that is, onto the projection surface 95. FIG. 3 is a simplified diagram showing the projection optical system 24. As shown in FIG. In FIG. 3, the vertical direction corresponds to the direction in which the modulation elements of the optical modulator 23 are arranged (hereinafter also referred to as the "long axis direction"). In reality, the optical axis is bent in the projection optical system 24, but in FIG. 3, the optical axis is shown expanded to be a straight line.

The first projection optical system 241 includes a first lens group 41 and a second lens group 42 in order from the optical modulator 23 side. The first lens group 41 is at least one lens. The second lens group 42 is also at least one lens. The second projection optical system 242 includes, in order from the first projection optical system 241 side, a third lens group 43, a scanning mechanism 44, and a fourth lens group 45. The third lens group 43 is at least one lens. In this embodiment, the scanning mechanism 44 is a combination of a galvano scanner that scans modulated light in the X direction and a galvano scanner that scans the modulated light in the Y direction. In FIG. 3, the scanning mechanism 44 is simplified and shown as two rectangles. The fourth lens group 45 is at least one lens.

The first projection optical system 241 has a reduction magnification. That is, the first projection optical system 241 forms a reduced intermediate image 84 of the optical modulator 23 . The first lens group 41 and the second lens group 42 may be composed of only spherical lenses, and the intermediate image 84 may be an image reduced by the same magnification in the major axis direction and the minor axis direction. However, when generating one-dimensional modulated light, the modulation in the long axis direction determines the shape of the object, so the first projection optical system 241 includes a cylindrical lens or the like to make the intermediate image 84 shorter than the long axis direction. It may be greatly reduced in the axial direction. In the case of one-dimensional modulated light, the magnification in the first projection optical system 241 refers to the magnification in the direction corresponding to the direction in which the modulation elements of the light modulator 23 are arranged.

On the other hand, the second projection optical system 242 has an enlargement magnification. The third lens group 43 is preferably a single lens or a laminated lens that suppresses aberrations. The fourth lens group 45 is also preferably a single lens or a laminated lens that suppresses aberrations. The second projection optical system 242 is preferably composed of only a spherical lens, and is a so-called fθ lens. The second projection optical system 242 may be image-side telecentric or image-side non-telecentric. Furthermore, the second projection optical system 242 may be a non-fθ lens. A projected image 85 of the intermediate image 84 is magnified and formed by the second projection optical system 242 on a projection plane 95 (that is, a powder surface) which is the surface of the material layer 92 . The second projection optical system 242 irradiates the intermediate image 84 as a multi-spot line beam (see reference numeral 8 in FIG. 1) onto a projection surface 95 which is a processing area. Further, the projection image 85 is scanned on the projection surface 95 by the scanning mechanism 44 . In FIG. 3, the manner in which the multi-spot line beam is scanned is simplified by branching the optical path from the scanning mechanism 44.

FIG. 4 is a diagram for explaining how the projection plane 95 of the material layer 92 is irradiated with a multi-spot line beam. In FIG. 4, the Y direction corresponds to the major axis direction. That is, the ON (light irradiation) and OFF (light non-irradiation) spots of the multi-spot line beam are lined up in the Y direction. Reference numeral 950 in FIG. 4 indicates the length of the spot row of the multi-spot line beam, and by moving the multi-spot line beam in the X direction by the scanning mechanism 44, one area 951 is drawn with modulated light. Hereinafter, the area 951 will be referred to as a "swath".

When the drawing for one swath 951 is completed, the scanning mechanism 44 performs drawing for the adjacent swath 951 in the +Y direction. By sequentially performing drawing on adjacent swaths 951, drawing on the projection surface 95 of the material layer 92, that is, exposure of the projection surface 95 by modulated light irradiation is completed.

FIG. 5 is a diagram showing a projection optical system 724 according to a comparative example, and corresponds to FIG. 3. The basic structure of the projection optical system 724 is the same as that in FIG. 3, but the first projection optical system 7241 has equal magnification (or enlarged magnification), and the second projection optical system 7242 has equal magnification (or reduced magnification). In FIG. 3, when the magnification of the entire projection optical system 24 is equal to the same magnification, the focal length of the fourth lens group 745 in FIG. 5 is shorter than the focal length of the fourth lens group 45 in FIG. As a result, the distance from the fourth lens group 745 to the projection surface 95, that is, the working distance becomes shorter. This narrows the range in which the multi-spot line beam can be scanned on the material layer 92, making it impossible to increase the size of the fabricated object.

For example, the modulation area of the optical modulator 23 is 27 mm in the long axis direction and 1 mm in the short axis direction, and both the second projection optical system 7242 of the comparative example and the second projection optical system 242 of the present embodiment It is assumed that the optical system is telecentric on both sides with an object-to-image distance of 1000 mm. Here, the magnification of the first projection optical system 7241 of the comparative example is 1.25, the magnification of the second projection optical system 7242 is 0.8, and the magnification of the first projection optical system 241 of the present embodiment is 0.25. 25. Assuming that the magnification of the second projection optical system 242 is 4 and the beam size at the projection surface 95 is 27 mm x 1 mm in both the comparative example and the present embodiment, the fourth lens group 745 of the comparative example The focal length of the lens is 222 mm, and the focal length of the fourth lens group 45 of this embodiment is 400 mm. Since the focal length of the fourth lens group is close to the working distance, this embodiment can ensure a sufficiently long working distance compared to the comparative example.

In the comparative example shown in FIG. 5, it is possible to secure the working distance by increasing the focal length of the fourth lens group 745, but in this case, the magnification of the second projection optical system 7242 becomes large and the processing area is The intensity of light irradiation (so-called fluence) decreases. As a result, it may be necessary to reduce the scanning speed in order to secure the exposure amount, resulting in a decrease in productivity. Furthermore, problems such as a decrease in modeling resolution may occur due to an increase in spot size. One possible solution is to lengthen the focal lengths of both the third lens group 743 and the fourth lens group 745, but in this case, the optical path length of the second projection optical system 7242 becomes longer, leading to an increase in the size of the optical head. A problem arises.

To solve the above problems, in the projection optical system 24 of FIG. 3, the first projection optical system 241 has a reduction magnification and the second projection optical system 242 has an enlargement magnification, thereby reducing the above-mentioned light irradiation intensity and improving productivity. It is possible to easily secure a long working distance while avoiding problems such as a decrease in image quality, a decrease in modeling resolution, and an increase in the length of the optical system. Alternatively, by setting the first projection optical system 241 to a reduction magnification, the second projection optical system 242 has an enlargement magnification to ensure a long working distance, but the overall projection magnification of the projection optical system 24 becomes excessively large. can be avoided.

In the above description, the case where the overall projection magnification of the projection optical system 24 is 1 has been described as an example, but of course, the projection magnification of the projection optical system 24 is not limited to 1. Since the modulation elements of the light modulator 23 are minute, the projection magnification of the projection optical system 24 is preferably designed to be 1 or more. Preferably, the projection magnification of the projection optical system 24 is 2 or less. In particular, when the light modulator 23 is a grating light valve (GLV (registered trademark)) or a planar light valve (PLV), the overall projection magnification of the projection optical system 24 (i.e., the The projection magnification by the first projection optical system 241 and the second projection optical system 242 does not need to be less than 1, and if it exceeds 2, the desired shape accuracy of the model cannot be obtained, so the overall projection magnification should be 1 or more and 2. The following is preferable.Also, when the modeling material 91 is nylon or PEEK (polyetheretherketone), it is preferable that the overall projection magnification is 1 or more and 2 or less.

In such a projection optical system 24, by making the projection magnification of the first projection optical system 241 smaller than the projection magnification of the second projection optical system 242, it is possible to ensure a long working distance as described above. be done. It is also unnecessary to increase the distance between the intermediate image 84 and the second projection optical system 242. In particular, by setting the projection magnification of the first projection optical system 241 to 1/2 or less of the overall projection magnification of the first projection optical system 241 and the second projection optical system 242, the projection magnification of the first projection optical system 241 can be increased. A significantly longer working distance can be secured compared to the case where the size is equal to or larger than the same size. Furthermore, although the fact that the projection magnification of the first projection optical system 241 is significantly smaller than 1/2 of the overall projection magnification has little effect on modeling, when considering the damage that the condensed light causes to the optical elements, the first The projection magnification of the projection optical system 241 is preferably 1/4 or more of the overall projection magnification. That is, the projection magnification of the first projection optical system 241 is preferably 1/4 or more and 1/2 or less of the overall projection magnification.

As described above, when the light modulator 23 is a one-dimensional spatial modulator, the projection magnification refers to the projection magnification in the long axis direction in which the modulation elements are arranged. In the above description, the first projection optical system 241 forms the intermediate image 84 of the light modulator 23 at a predetermined intermediate position, but when the light modulator 23 is a one-dimensional spatial modulator, the "intermediate image" is means an image in the long axis direction. That is, in the first projection optical system 241, the optical modulator 23 and the intermediate image 84 have a conjugate positional relationship in the long axis direction. Of course, when the first projection optical system 241 has the same projection magnification in the major axis direction and the minor axis direction, the projection magnification of the first projection optical system 241 is these projection magnifications. Note that the first projection optical system 241 may include only one lens. The first projection optical system 241 may have one lens group or three or more lens groups.

The second projection optical system 242 forms a projection image 85 of the intermediate image 84 on the projection surface 95 of the modeling material 91. Further, the second projection optical system 242 uses the scanning mechanism 44 to scan the projected image 85 on the projection surface 95 . Since the second projection optical system 242 is provided for scanning the projection image 85, preferably the projection magnification is the same in the major axis direction and the minor axis direction. Of course, the projection magnification of the second projection optical system 242 may be determined as the projection magnification in the major axis direction. In the scanning mechanism 44, a scanning mechanism having another structure such as a polygon laser scanner may be provided instead of the galvano scanner. The scanning by the scanning mechanism 44 does not necessarily need to be carried out two-dimensionally as long as it is carried out in a direction intersecting the long axis direction. That is, one material layer 92 may be scanned by the multi-spot line beam only once in one direction. A projection image 85 of the intermediate image 84 is formed on the projection surface 95 by the second projection optical system 242, but in a strict sense, the intermediate position where the intermediate image 84 is formed and the projection surface 95 are optically conjugate. It doesn't have to be. The projection plane 95 may be slightly shifted from a position conjugate to the intermediate position within the range in which three-dimensional modeling is possible.

As a diffractive optical modulator 23 having multiple modulation elements, a PLV with high power resistance is preferable. The optical modulator 23 is not limited to a one-dimensional spatial modulator. It may also be a two-dimensional spatial light modulator, for example, a DMD (Digital Micromirror Device). Modulators based on various principles can be used as the optical modulator 23, as long as they can control the illumination and non-illumination of light at multiple positions in the projected image.

The light source of the optical head 11 is not limited to the laser light source 21. A variety of other known light sources may be employed. Various optical systems may be employed for the illumination optical system 22 as long as they can converge and guide light to the regions of the plurality of modulation elements of the light modulator 23.

The layer forming member 323 of the layer forming mechanism 12 is not limited to a squeegee. A roller or a member that spreads the modeling material 91 may be used as the layer forming member. When the layer forming member 323 moves along the projection surface 95 between the second projection optical system 242 and the projection surface 95 on which the projected image 85 is scanned, it is particularly preferable to use an optical head 11 having the above structure that can obtain a long working distance. The layer forming mechanism 12 may be a mechanism that does not have a layer forming member 323. Various other mechanisms may be used as the layer forming mechanism 12 as long as a new projection surface 95 can be formed by forming a new material layer 92 of the modeling material 91 on the projection surface 95 on which the projected image 85 is scanned.

The configurations in the above embodiment and each modified example may be combined as appropriate as long as they are not mutually inconsistent.

Although the invention has been described and described in detail, the above description is illustrative and not restrictive. Therefore, it can be said that many modifications and embodiments are possible without departing from the scope of the present invention.

REFERENCE SIGNS LIST 1 3D modeling device 12 Layer formation mechanism 21 Light source 22 Illumination optical system 23 Light modulator 44 Scanning mechanism 84 Intermediate image 85 Projected image 91 Modeling material 92 Material layer 95 Projection surface 230 Pixel row (modulation element)
241 First projection optical system 242 Second projection optical system 323 Layer forming member

Claims

A three-dimensional printing device,
a light source and
a diffractive optical modulator having a plurality of modulation elements;
an illumination optical system that guides light from the light source to the light modulator;
a first projection optical system that forms an intermediate image of the optical modulator at a predetermined intermediate position;
a second projection optical system that forms a projected image of the intermediate image on a projection surface of the modeling material;
a layer forming mechanism that forms a layer of the modeling material;
Equipped with
The second projection optical system includes a scanning mechanism that scans the projected image on the projection surface,
The layer forming mechanism forms a new projection surface by forming a new layer of the modeling material on the projection surface on which the projection image has been scanned,
A three-dimensional modeling apparatus in which a projection magnification of the first projection optical system is smaller than a projection magnification of the second projection optical system.
The three-dimensional printing device according to claim 1,
The projection magnification of the first projection optical system is a reduction magnification,
A three-dimensional modeling apparatus, wherein the projection magnification of the second projection optical system is an enlargement magnification.
The three-dimensional printing device according to claim 1,
A three-dimensional modeling apparatus, wherein the light modulator is a diffraction grating light valve or a plane light valve.
The three-dimensional printing device according to claim 1,
A three-dimensional modeling apparatus, wherein the projection magnification of the first projection optical system is 1/4 or more and 1/2 or less of the overall projection magnification of the first projection optical system and the second projection optical system.
The three-dimensional printing device according to claim 4,
the light modulator is a grating light valve or a planar light valve;
A three-dimensional modeling apparatus, wherein the overall projection magnification is 1 or more and 2 or less.
The three-dimensional printing apparatus according to any one of claims 1 to 5,
A three-dimensional modeling apparatus in which the layer forming mechanism includes a layer forming member that moves along the projection surface between the second projection optical system and the projection surface on which the projection image is scanned.