Stereolithography device and structure manufacturing method

Abstract

A stereolithography device (1A) comprises: a first light source (101) that outputs first light (L1); a second light source (102) that outputs second light (L2); a spatial light modulator (DMD103) that is controlled to have a first modulation pattern in a first state and to have a second modulation pattern in a second state; an optical path changing optical system (110) that changes optical paths of the first light (L1) and the second light (L2) such that the first light (L1) is incident on the spatial light modulator (DMD103) in the first state and the second light (L2) is incident on the spatial light modulator (DMD103) in the second state; and an irradiation optical system (imaging lens 104, aperture stop 105, beam splitter 106, and first objective lens 107) that irradiates a molding surface (S) with the first light (L1) in a first irradiation pattern in the first state and irradiates the molding surface (S) with the second light (L2) in a second irradiation pattern in the second state.

Description

Optical shaping device and method for manufacturing a structure

[0001] The present disclosure relates to an optical shaping device that shapes a structure by curing a photocurable resin. The present disclosure also relates to a method for manufacturing a structure that shapes a structure by curing a photocurable resin.

[0002] Optical shaping technology for shaping a structure by curing a photocurable resin is widely used. Also, as an improved optical shaping technology, in addition to irradiating a region corresponding to the inside of the structure to be shaped with curing-accelerating light, a two-wavelength shaping technology that irradiates a region corresponding to the outside of the structure to be shaped with curing-inhibiting light is known. By using the two-wavelength shaping technology, it is possible to eliminate or suppress the bluntness of the shape that can occur at the contour of the structure. Examples of documents that disclose a conventional optical shaping device that performs two-wavelength shaping include Patent Document 1.

[0003] U.S. Patent Application Publication No. 2022 / 0143906

[0004] In a conventional optical shaping device that performs two-wavelength shaping, since the irradiation pattern of the curing-accelerating light and the irradiation pattern of the curing-inhibiting light are different, it is necessary to use two spatial light modulators. The first spatial light modulator is a spatial light modulator for spatially modulating the curing-accelerating light, and the second spatial light modulator is a spatial light modulator for spatially modulating the curing-inhibiting light. Therefore, in a conventional optical shaping device that performs two-wavelength shaping, position adjustment among three bodies, that is, (1) the first spatial light modulator, (2) the second spatial light modulator, and (3) the irradiation optical system (an optical system for irradiating the shaping surface with the curing-accelerating light spatially modulated by the first spatial light modulator and the curing-inhibiting light spatially modulated by the second spatial light modulator) is required, and there is a problem that it is difficult to perform the position adjustment among these three bodies. Such a problem is not limited to an optical shaping device that performs two-wavelength shaping, but is a problem that can generally occur in an optical shaping device that irradiates a shaping surface with two or more types of light in different irradiation patterns.

[0005] One aspect of the present invention has been made in view of the above-mentioned problems, and its object is to provide a photopolymerization technology that can irradiate the fabrication surface with two or more types of light in different irradiation patterns without using two or more spatial light modulators.

[0006] A stereolithography apparatus according to one aspect of the present invention is characterized by comprising: a first light source that outputs first light; a second light source that outputs second light; a spatial light modulator that is controlled to a first modulation pattern in a first state and to a second modulation pattern different from the first modulation pattern in a second state; an optical path changing optical system that changes the optical paths of the first light output from the first light source and the second light output from the second light source so that the first light is incident on the spatial light modulator in the first state and the second light is incident on the spatial light modulator in the second state; and an irradiation optical system that, in the first state, irradiates the molding surface set in a photocurable resin with the first light, which has been spatially modulated by the spatial light modulator, in a first irradiation pattern, and in the second state, irradiates the molding surface with the second light, which has been spatially modulated by the spatial light modulator, in a second irradiation pattern different from the first irradiation pattern.

[0007] A method for manufacturing a structure according to one aspect of the present invention is characterized by alternatingly repeating the operation of spatially modulating a first light output from a first light source using a spatial light modulator controlled to a first modulation pattern, and the operation of spatially modulating a second light output from a second light source using the spatial light modulator controlled to a second modulation pattern different from the first modulation pattern, thereby manufacturing a structure made of the photocurable resin after curing by alternately irradiating the molding surface set in the photocurable resin before curing with the first light and the second light using different irradiation patterns in a time-division manner.

[0008] According to one aspect of the present invention, it is possible to provide a photopolymerization technology that can irradiate the fabricated surface with two or more types of light in different irradiation patterns without using two or more spatial light modulators.

[0009] (a) is a plan view showing the configuration of a stereolithography apparatus according to the first embodiment of the present invention. (b) is a plan view showing the first state of the stereolithography apparatus shown in (a), and (c) is a plan view showing the second state of the stereolithography apparatus shown in (a). (a) is a plan view showing the configuration of a stereolithography apparatus according to the second embodiment of the present invention. (b) is a plan view showing the first state of the stereolithography apparatus shown in (a), and (c) is a plan view showing the second state of the stereolithography apparatus shown in (a). (a) is a plan view showing the configuration of a stereolithography apparatus according to the third embodiment of the present invention. (b) is a plan view showing the first state of the stereolithography apparatus shown in (a), and (c) is a plan view showing the second state of the stereolithography apparatus shown in (a). (a) is a plan view showing a modified example of the stereolithography apparatus shown in Figure 1. (b) is a plan view showing a modified example of the stereolithography apparatus shown in Figure 2. (c) is a block diagram showing a modified example of the stereolithography apparatus shown in Figure 3. Figures 1 to 4 are perspective views showing a specific example of a structure manufactured using a stereolithography apparatus.

[0010] [First Embodiment] (Configuration of Stereolithography Apparatus) The configuration of the stereolithography apparatus 1A according to the first embodiment will be described with reference to Figure 1(a). Figure 1(a) is a plan view showing the configuration of the stereolithography apparatus 1A according to this embodiment.

[0011] The stereolithography apparatus 1A is a device for manufacturing resin structures. As shown in Figure 1(a), the stereolithography apparatus 1A includes a container 100, a first light source 101, a second light source 102, a DMD (Digital Mirror Device) 103, an imaging lens (tube lens) 104, an aperture diaphragm 105, a beam splitter 106, a first objective lens 107, a second objective lens 108, an image sensor 109, an optical path changing optical system 110, and a control device (not shown).

[0012] Hereinafter, the optical system composed of the imaging lens 104, aperture diaphragm 105, beam splitter 106, and first objective lens 107 will also be referred to as the "illumination optical system." In one embodiment of the present invention, the illumination optical system includes at least one lens and is an optical system that guides light modulated by a spatial light modulator to the build surface. The illumination optical system is preferably arranged so as to image the light output from the light source and modulated by the spatial light modulator onto the build surface. Therefore, it is preferable that the illumination optical system is arranged such that the spatial light modulator, which is the object surface, and the build surface, which is the image surface, are in a conjugate relationship. However, the light guided to the build surface by the spatial light modulator may not be imaged and may be blurred to the extent required for the accuracy of the build object. In other words, the relationship between the spatial light modulator and the build surface may be shifted from a conjugate relationship to the extent required for the accuracy of the build object. In this case, the illumination optical system projects the light output from the light source and modulated by the spatial light modulator onto the build surface. Furthermore, the optical system composed of the second objective lens 108 and the image sensor 109 is also referred to as the "imaging optical system."

[0013] The first light source 101 is a light source that outputs a first light L1. The second light source 102 is a light source that outputs a second light L2. The first light source 101 and the second light source 102 are composed of, for example, LEDs (Light Emitting Diodes). In this embodiment, the first light L1 output from the first light source 101 and the second light L2 output from the second light source 102 are light with different wavelengths. Also, the first light L1 output from the first light source 101 and the second light L2 output from the second light source are light with the same polarization direction (linearly polarized).

[0014] The container 100 is configured to store a photocurable resin P (including a polymerization initiator and a polymerization inhibitor) before curing. The bottom plate of the container 100 is made of a translucent material that transmits a first light L1 output from a first light source 101 and a second light L2 output from a second light source 102. In the photopolymerization apparatus 1A, the first light L1 output from the first light source 101 and the second light L2 output from the second light source 102 are alternately time-division irradiated onto the molding surface S set near the bottom plate of the container 100. As a result, a structure made of the cured photocurable resin P is fabricated.

[0015] For example, the first light L1 output from the first light source 101 is a accelerating light that promotes the curing of the photocurable resin P, and the second light L2 output from the second light source 102 is an inhibiting light that inhibits the curing of the photocurable resin P. Examples of accelerating light include light whose wavelength matches an integer multiple of the wavelength belonging to the absorption wavelength band of the polymerization initiator. When light whose wavelength matches the wavelength belonging to the absorption wavelength band of the polymerization initiator is used as accelerating light, curing by a one-photon absorption reaction is promoted. Alternatively, when light whose wavelength matches twice the wavelength belonging to the absorption wavelength band of the polymerization initiator is used as accelerating light, curing by a two-photon absorption reaction is promoted. In general, when light whose wavelength matches n times the wavelength belonging to the absorption wavelength band of the polymerization initiator is used as accelerating light, curing by an n-photon absorption reaction is promoted. On the other hand, examples of inhibiting light include light whose wavelength matches the wavelength belonging to the absorption wavelength band of the polymerization inhibitor.

[0016] The stereolithography apparatus 1A can operate in both a "first state" and a "second state". Here, the "first state" refers to the state in which the first light L1 output from the first light source 101 is incident on the DMD 103, and the first light L1 reflected by the DMD 103 is irradiated onto the molding surface S in a first irradiation pattern. The "second state" refers to the state in which the second light L2 output from the second light source 102 is incident on the DMD 103, and the second light L2 reflected by the DMD 103 is irradiated onto the molding surface S in a second irradiation pattern. Here, the second irradiation pattern is different from the first irradiation pattern.

[0017] The optical path changing optical system 110 is an optical system for changing the optical paths of the first light L1 and the second light L2 so that in the first state, the first light L1 output from the first light source 101 is incident on the DMD 103, and in the second state, the second light L2 output from the second light source is incident on the DMD 103. Hereinafter, the light incident on the DMD 103 will also be referred to as "light L". In the first state, light L is the same as the first light L1, and in the second state, light L is the same as the second light L2. The configuration of the optical path changing optical system 110 will be described later.

[0018] The DMD 103 is composed of a group of micromirrors arranged in a matrix. Each micromirror is controlled to either an ON state or an OFF state by a control device (not shown). The DMD 103 reflects the light L incident on the ON-state micromirrors and absorbs the light L incident on the OFF-state micromirrors. Therefore, the light L reflected by the DMD 103 has a spatial intensity distribution corresponding to the modulation pattern of the DMD 103. In other words, the DMD 103 functions as a reflective spatial light modulator. The modulation pattern of the DMD 103 is the distribution of the micromirrors controlled to the ON state in the group of micromirrors constituting the DMD 103. The distribution of the micromirrors controlled to the OFF state in the group of micromirrors constituting the DMD 103 may also be considered as the modulation pattern of the DMD 103.

[0019] The imaging lens 104 is configured to collimate the light L reflected by the DMD 103. The imaging lens 104 is positioned on the optical axis of the light L reflected by the DMD 103 such that the front focal point of the imaging lens 104 is located on the reflective surface of the DMD 103.

[0020] The aperture diaphragm 105 is configured to limit the numerical aperture of the light L that passes through the imaging lens 104. The aperture diaphragm 105 is positioned on the optical path of the light L that passes through the imaging lens 104.

[0021] The beam splitter 106 is configured to reflect the light L that has passed through the aperture diaphragm 105 and to transmit the scattered light scattered at the molding surface S. The beam splitter 106 is positioned on the optical path of the light L that has passed through the aperture diaphragm 105 such that the angle between the light L that has passed through the aperture diaphragm 105 and the functional surface is 45°. Here, the functional surface has the function of reflecting polarization components having a specific polarization direction and transmitting polarization components having other polarization directions, which are embedded in the beam splitter 106. The beam splitter 106 reflects the light L that has passed through the aperture diaphragm 105 and changes its direction of propagation by 90°.

[0022] The first objective lens 107 is configured to focus the light L reflected by the beam splitter 106. The first objective lens 107 is positioned in the optical path of the light L reflected by the beam splitter 106 such that the rear focal point of the first objective lens 107 is located on the build surface S. As a result, the light L that passes through the first objective lens 107 is irradiated onto the build surface S in an irradiation pattern corresponding to the modulation pattern of the DMD 103.

[0023] When light L is shone onto the build surface S via the first objective lens 107, scattered light is generated at each point on the build surface S. The scattered light generated at each point on the build surface S is imaged onto the light-receiving surface of the image sensor 109 via the first objective lens 107, the beam splitter 106, and the second objective lens 108. This makes it possible to observe the build surface S by referring to the output signal of the image sensor 109.

[0024] Furthermore, if observation of the molded surface S is not required, the second objective lens 108 and the image sensor 109 constituting the imaging optical system may be omitted. In this case, the first light L1 output from the first light source 101 and the second light L2 output from the second light source 102 do not need to be linearly polarized with a specific polarization direction.

[0025] (Configuration of the optical path changing optical system) The configuration of the optical path changing optical system 110 will be explained further with reference to Figure 1(a).

[0026] The optical path changing optical system 110 is composed of a first shutter 111, a second shutter 112, a dichroic mirror 113, and a folding mirror 114.

[0027] The first shutter 111 is positioned on the optical path of the first light L1 output from the first light source 101. The first shutter 111 is switched from an open state to a closed state by a control device (not shown) during the transition from the first state to the second state. The first shutter 111 is also switched from a closed state to an open state by a control device (not shown) during the transition from the second state to the first state. Therefore, the first light L1 output from the first light source 101 passes through the first shutter 111 in the first state and is shielded by the first shutter 111 in the second state.

[0028] The second shutter 112 is positioned on the optical path of the second light L2 output from the second light source 102. The second shutter 112 is switched from a closed state to an open state by a control device (not shown) during the transition from the first state to the second state. Similarly, the second shutter 112 is switched from a closed state to an open state by a control device (not shown) during the transition from the second state to the first state. Therefore, the second light L2 output from the second light source 102 passes through the second shutter 112 in the second state and is shielded by the second shutter 112 in the first state.

[0029] The first shutter 111 and the second shutter 112 can be configured, for example, with Pockels cells. This allows for faster switching between the open and closed states. Alternatively, the first shutter 111 and the second shutter 112 can be configured with mechanical shutters. This allows for increased light transmittance in the open state and decreased light transmittance in the closed state.

[0030] The dichroic mirror 113 is configured to reflect the first light L1 that has passed through the first shutter 111 in the first state, and to transmit the second light L2 that has passed through the second shutter 112 in the second state. The dichroic mirror 113 is positioned at the intersection of the optical path of the first light L1 that has passed through the first shutter 111 and the optical path of the second light L2 that has passed through the second shutter 112. Furthermore, the orientation of the dichroic mirror 113 is set so that the optical path of the first light L1 reflected by the dichroic mirror 113 and the optical path of the second light L2 that has passed through the dichroic mirror 113 pass through a common optical path and enter the DMD 103.

[0031] The folding mirror 114 is configured to reflect the first light L1 reflected by the dichroic mirror 113 in the first state and the second light L2 transmitted through the dichroic mirror 113 in the second state, and guide them to the DMD 103. The folding mirror 114 is positioned on the common optical path of the first light L1 reflected by the dichroic mirror 113 and the second light L2 transmitted through the dichroic mirror 113. The orientation of the folding mirror 114 is set so that the first light L1 and L2 reflected by the folding mirror 114 are incident on the DMD 103.

[0032] (Operation and Effects of the Stereolithography Apparatus) The operation of the stereolithography apparatus 1A will be described with reference to Figures 1(b) and 1(c). Figure 1(b) is a plan view showing the stereolithography apparatus 1A in the first state. Figure 1(c) is a plan view showing the stereolithography apparatus 1A in the second state.

[0033] In order to switch the state of the stereolithography apparatus 1A from the second state to the first state, a control device (not shown) operates the DMD 103 and the optical path changing optical system 110 as follows.

[0034] (1) Close the second shutter 112 (the first shutter 111 is closed).

[0035] (2) Switch the modulation pattern of the DMD103 to the first modulation pattern.

[0036] (3) Open the first shutter 111.

[0037] As a result, the state shown in (b) of FIG. 1, that is, the first state in which the first light L1 output from the first light source 101 irradiates the shaping surface S in the first irradiation pattern corresponding to the first modulation pattern, is realized.

[0038] In the first state, the second light source 102 may be lit or turned off. When the second light source 102 is lit, the second light L2 output from the second light source 102 is absorbed or reflected by the second shutter 112.

[0039] In order to switch the state of the optical shaping apparatus 1A from the first state to the second state, a control device (not shown) operates the DMD 103 and the optical path changing optical system 110 as follows.

[0040] (4) Close the first shutter 111 (the second shutter 112 is closed).

[0041] (5) Switch the modulation pattern of the DMD 103 to a second modulation pattern different from the above-described first modulation pattern.

[0042] (6) Open the second shutter 112.

[0043] As a result, the state shown in (c) of FIG. 1, that is, the second state in which the second light L2 output from the second light source 102 irradiates the shaping surface S in the second irradiation pattern corresponding to the second modulation pattern, is realized.

[0044] In the second state, the first light source 101 may be lit or turned off. When the first light source 101 is lit, the first light L1 output from the first light source 101 is absorbed or reflected by the first shutter 111.

[0045] The control unit (not shown) repeats the above-described controls (1) to (6). As a result, the stereolithography apparatus 1A alternately time-divisionally irradiates the first light L1 (e.g., promoting light) output from the first light source 101 and the second light L2 (e.g., inhibiting light) output from the second light source 102 with different irradiation patterns. The effect of the alternately time-divisionally irradiated lights L1 and L2 on the photocurable resin P approaches the effect of the lights L1 and L2 continuously irradiated simultaneously with different irradiation patterns as the duration of the first state and the duration of the second state are shortened.

[0046] The switching control of the modulation pattern of the DMD 103 is performed during the period when both the first shutter 111 and the second shutter 112 are in the closed state. Therefore, a situation where the first light L1 output from the first light source 101 is erroneously irradiated onto the shaping surface S with the second irradiation pattern or the second light L2 output from the second light source 102 is erroneously irradiated onto the shaping surface S with the first irradiation pattern hardly occurs.

[0047] When the first light L1 output from the first light source 101 is promoting light and the second light L2 output from the second light source 102 is inhibiting light, the duration of the first state and the duration of the second state are preferably each 1 / 10 or less (e.g., 0.1 seconds or less) of the curing time (e.g., 1 second) when only the first light L1 output from the first light source 101 is continuously irradiated. Thereby, an effect similar to the case where the first light L1 as promoting light and the second light L2 as inhibiting light are continuously irradiated simultaneously with different irradiation patterns can be obtained.

[0048] For example, the irradiation pattern of the first light L1 as promoting light is set as an irradiation pattern for selectively irradiating the first light L1 to the inside of the curing target region on the shaping surface S, and the irradiation pattern of the second light L2 as inhibiting light is set as an irradiation pattern for selectively irradiating the second light L2 to the outside of the curing target region on the shaping surface S. By doing so, it becomes difficult for the shape to blunt at the contour of the shaped object, and it becomes possible to shape the shaped object as designed with high accuracy.

[0049] Furthermore, if a control device (not shown) performs the above-described controls (1) to (6), the duration of the first state is the time from when the first shutter 111 is opened in control (3) until when the first shutter 111 is closed in control (4). The duration of the second state is the time from when the second shutter 112 is opened in control (6) until when the second shutter 112 is closed in control (1).

[0050] The stereolithography apparatus 1A has the following advantages. Specifically, when the first light L1 output from the first light source 101 and the second light L2 output from the second light source 102 are simultaneously and continuously irradiated in different patterns, two DMDs are required, and the difficult task of aligning the three bodies, i.e., aligning one DMD with the other DMD and the irradiation optical system, is required. In contrast, when the first light L1 output from the first light source 101 and the second light L2 output from the second light source 102 are alternately irradiated in different patterns using time-division multiplexing, one DMD is sufficient, and the easy task of aligning the two bodies, i.e., aligning one DMD with the irradiation optical system, is sufficient. As a result, the number of parts in the stereolithography apparatus 1A is reduced, and the effort required to assemble the stereolithography apparatus 1A is also reduced.

[0051] In this embodiment, a configuration is adopted in which accelerating light and inhibiting light are alternately irradiated in different irradiation patterns in a time-division manner, but the present invention is not limited thereto. For example, a configuration may be adopted in which two types of accelerating light are alternately irradiated in different irradiation patterns in a time-division manner. In this case, for example, the first light source 101 outputs a first light L1 whose wavelength matches n times the wavelength belonging to the absorption wavelength band of the polymerization initiator, as accelerating light to promote the curing of the photocurable resin P by an n-photon absorption reaction (where n is any integer of 1 or more). In addition, the second light source 102 outputs a second light L2 whose wavelength matches m times the wavelength belonging to the absorption wavelength band of the polymerization initiator, as accelerating light to promote the curing of the photocurable resin P by an m-photon absorption reaction (where m is any integer of n+1 or more).

[0052] In this case, for example, the irradiation pattern of the first light L1, which is a shorter wavelength accelerating light, is set to selectively irradiate a larger area located in the center of the area to be cured, and the irradiation pattern of the second light L2, which is a longer wavelength accelerating light, is set to selectively irradiate a smaller area located in the periphery of the area to be cured. This allows for precise tracing of the contour of the fabricated object, making it possible to fabricate an object with high precision according to the design.

[0053] (Modified Stereolithography Apparatus) A modified example of the stereolithography apparatus 1A will be described with reference to Figure 4(a). Figure 4(a) is a plan view showing the configuration of the stereolithography apparatus 1A according to this modified example (hereinafter referred to as "stereolithography apparatus 1A'").

[0054] Stereolithography apparatus 1A' is modified by replacing the DMD 103 of stereolithography apparatus 1A, which is a reflective spatial light modulator, with an LCOS (Liquid Crystal On Silicon) 103', which is a transmissive spatial light modulator. This replacement alters the arrangement of the first light source 101, the second light source 102, the first shutter 111, the second shutter 112, and the dichroic mirror 113, and the folding mirror 114 is omitted.

[0055] LCOS103' is composed of a matrix of liquid crystal pixels. The transmittance of each liquid crystal pixel is controlled by a control device (not shown). Light transmitted through LCOS103' has a spatial intensity distribution corresponding to the modulation pattern of LCOS103'. In other words, LCOS103' functions as a transmissive spatial light modulator. The modulation pattern of LCOS103' is the distribution of transmittance in the liquid crystal pixel group constituting LCOS103'.

[0056] The operation and effects of the stereolithography apparatus 1A' are the same as those of the stereolithography apparatus 1A, so their explanation is omitted here.

[0057] [Second Embodiment] (Configuration of Stereolithography Apparatus) The configuration of the stereolithography apparatus 1B according to the second embodiment will be described with reference to Figure 2(a). Figure 2(a) is a plan view showing the configuration of the stereolithography apparatus 1B according to this embodiment.

[0058] The stereolithography apparatus 1B is a device for manufacturing resin structures. As shown in Figure 2(a), the stereolithography apparatus 1B includes a container 100, a first light source 101, a second light source 102, a DMD (Digital Mirror Device) 103, an imaging lens 104, an aperture diaphragm 105, a beam splitter 106, a first objective lens 107, a second objective lens 108, an image sensor 109, and an optical path changing optical system 120. The stereolithography apparatus 1B may also further include a control device (e.g., a computer) which is not shown.

[0059] The difference between the stereolithography apparatus 1B according to this embodiment and the stereolithography apparatus 1A according to the first embodiment is that the optical path changing optical system 110 is replaced by the optical path changing optical system 120. The optical path changing optical system 120 will be described below, and the remaining configuration will not be described. In this embodiment, the wavelength of the first light L1 output from the first light source 101 and the wavelength of the second light L2 output from the second light source 102 may or may not be the same.

[0060] (Configuration of the optical path changing optical system) The configuration of the optical path changing optical system 120 will be explained further with reference to Figure 2(a).

[0061] The optical system 120 is composed of a movable mirror 121.

[0062] The movable mirror 121 is configured to reflect the first light L1 output from the first light source 101 and the second light L2 output from the second light source 102. The movable mirror 121 is positioned at the intersection of the optical path of the first light L1 output from the first light source 101 and the optical path of the second light L2 output from the second light source 102. The orientation of the movable mirror 121 in the first state and the second state is set so that the first light L1 reflected by the movable mirror 121 in the first state and the second light L2 reflected by the movable mirror 121 in the second state pass through a common optical path and enter the DMD 103.

[0063] (Operation and Effects of the Stereolithography Apparatus) The operation of the stereolithography apparatus 1B will be explained with reference to Figures 2(b) and 2(c). Figure 2(b) is a plan view showing the stereolithography apparatus 1B in the first state. Figure 2(c) is a plan view showing the stereolithography apparatus 1B in the second state.

[0064] In order to switch the state of the stereolithography apparatus 1B from the second state to the first state, the control device (not shown) operates the DMD 103 and the optical path changing optical system 120 as follows.

[0065] (1) Switch all micromirrors that make up the DMD103 to the OFF state.

[0066] (2) The orientation of the movable mirror 121 is changed so that the first light L1 reflected by the movable mirror 121 is incident on the DMD 103, and the second light L2 reflected by the movable mirror 121 is not incident on the DMD 103.

[0067] (3) Switch the modulation pattern of the DMD103 to the first modulation pattern.

[0068] This realizes the state shown in Figure 2(b), that is, the first state in which the first light L1 output from the first light source 101 is irradiated onto the molding surface S in a first irradiation pattern corresponding to the first modulation pattern.

[0069] In the first state, the second light source 102 may be lit or unlit. When the second light source 102 is lit, the second light L2 output from the second light source 102 is either radiated outside the stereolithography apparatus 1B or absorbed by a light-shielding member provided inside the stereolithography apparatus 1B.

[0070] In order to switch the state of the stereolithography apparatus 1B from the first state to the second state, a control device (not shown) operates the DMD 103 and the optical path changing optical system 120 as follows.

[0071] (4) Switch all micromirrors that make up the DMD103 to the OFF state.

[0072] (5) The orientation of the movable mirror 121 is changed so that the second light L2 reflected by the movable mirror 121 enters the DMD 103, and the first light L1 reflected by the movable mirror 121 does not enter the DMD 103.

[0073] (6) Switch the modulation pattern of the DMD103 to the second modulation pattern.

[0074] This realizes the state shown in Figure 2(c), that is, the second state in which the second light L2 output from the second light source 102 is irradiated onto the molding surface S in a second irradiation pattern corresponding to the second modulation pattern.

[0075] In the second state, the first light source 101 may be lit or unlit. When the first light source 101 is lit, the first light L1 output from the first light source 101 is either radiated outside the stereolithography apparatus 1B or absorbed by a light-shielding member provided inside the stereolithography apparatus 1B.

[0076] A control unit (not shown) repeats the controls described in (1) to (6) above. As a result, the stereolithography apparatus 1B alternately time-divisions irradiates the first light L1 (e.g., accelerating light) output from the first light source 101 and the second light L2 (e.g., inhibiting light) output from the second light source 102 in different irradiation patterns. The effect of the first light L1 and L2, which are alternately time-divisions irradiated in different irradiation patterns on the photocurable resin P approaches the effect of the first light L1 and L2, which are simultaneously and continuously irradiated in different irradiation patterns, as the duration of the first state and the duration of the second state are shortened.

[0077] When the first light L1 output from the first light source 101 is a accelerating light and the second light L2 output from the second light source 102 is an inhibiting light, it is preferable that the duration of the first state and the duration of the second state are 1 / 10 or less (for example, 0.1 seconds or less) of the curing time (for example, 1 second) when only the first light L1 output from the first light source 101 is continuously irradiated (for example, 1 second). This makes it possible to obtain the same effect as when the first light L1, which is an accelerating light, and the second light L2, which is an inhibiting light, are continuously irradiated simultaneously in different irradiation patterns.

[0078] For example, the irradiation pattern of the first light L1, which is a accelerating light, is set to selectively irradiate the inside of the area to be cured on the fabricated surface S with the first light L1, and the irradiation pattern of the second light L2, which is an inhibiting light, is set to selectively irradiate the outside of the area to be cured on the fabricated surface S with the second light L2. In this case, blurring of the shape of the contour of the fabricated object is less likely to occur, making it possible to fabricate an object with high precision as designed.

[0079] Furthermore, when a control device (not shown) performs the above-described controls (1) to (6), the duration of the first state is the time from when the modulation pattern of the DMD 103 is switched to the first modulation pattern in control (3) until when the modulation pattern of the DMD 103 is switched to the all-off pattern in control (4). The duration of the second state is the time from when the modulation pattern of the DMD 103 is switched to the second modulation pattern in control (6) until when the modulation pattern of the DMD 103 is switched to the all-off pattern in control (1).

[0080] The effect of the stereolithography apparatus 1B is the same as that of the stereolithography apparatus 1A. Also, similar to the stereolithography apparatus 1A, instead of a configuration in which accelerating light and inhibiting light are alternately irradiated in different patterns in time-division time, a configuration in which two types of accelerating light are alternately irradiated in different patterns in time-division time can be adopted.

[0081] (Modified Stereolithography Apparatus) A modified example of the stereolithography apparatus 1B will be described with reference to Figure 4(b). Figure 4(b) is a plan view showing the configuration of the stereolithography apparatus 1B according to this modified example (hereinafter referred to as "stereolithography apparatus 1B'").

[0082] The stereolithography apparatus 1B' is modified by replacing the DMD 103 of the stereolithography apparatus 1A, which is a reflective spatial light modulator, with an LCOS (Liquid Crystal On Silicon) 103', which is a transmissive spatial light modulator. This replacement has resulted in changes to the arrangement of the first light source 101, the second light source 102, and the movable mirror 121.

[0083] LCOS103' is composed of a matrix of liquid crystal pixels. The transmittance of each liquid crystal pixel is controlled by a control device (not shown). Light transmitted through LCOS103' has a spatial intensity distribution corresponding to the modulation pattern of LCOS103'. In other words, LCOS103' functions as a transmissive spatial light modulator. The modulation pattern of LCOS103' is the distribution of transmittance in the liquid crystal pixel group constituting LCOS103'.

[0084] The operation and effects of the stereolithography apparatus 1B' are the same as those of the stereolithography apparatus 1B, so their explanation is omitted here.

[0085] [Third Embodiment] (Configuration of Stereolithography Apparatus) The configuration of the stereolithography apparatus 1C according to the third embodiment will be described with reference to Figure 3(a). Figure 3(a) is a plan view showing the configuration of the stereolithography apparatus 1C according to this embodiment.

[0086] The stereolithography apparatus 1C is a device for manufacturing resin structures. As shown in Figure 3(a), the stereolithography apparatus 1C includes a container 100, a first light source 101, a second light source 102, a DMD (Digital Mirror Device) 103, an imaging lens 104, an aperture diaphragm 105, a beam splitter 106, a first objective lens 107, a second objective lens 108, an image sensor 109, and a position change mechanism 130. The stereolithography apparatus 1C may also include a control device (e.g., a computer) which is not shown.

[0087] The difference between the stereolithography apparatus 1A and the stereolithography apparatus 1C is that the optical path changing optical system 110 is replaced by a position changing mechanism 130. The position changing mechanism 130 will be described below, and the remaining components will not be explained. In this embodiment, the wavelength of the first light L1 output from the first light source 101 and the wavelength of the second light L2 output from the second light source 102 may or may not be the same.

[0088] (Configuration of the position change mechanism) The configuration of the position change mechanism 130 will be explained further with reference to Figure 3(a).

[0089] The position changing mechanism 130 is a mechanism for changing the positions of the first light source 101 and the second light source 102 so that in the first state, the first light L1 output from the first light source 101 is incident on the DMD 103, and in the second state, the second light L2 output from the second light source 102 is incident on the DMD 103. The positions of the first light source 101 and the second light source 102 in each of the first and second states are set so that the first light L1 output from the first light source 101 in the first state and the second light L2 output from the second light source 102 in the second state are incident on the DMD 103 through a common optical path.

[0090] The position changing mechanism 130 can be configured, for example, by a rotating stage 131. The rotating stage 131 rotates the positions of the first light source 101 and the second light source 102 around the DMD 103. In the first state, the rotating stage 131 arranges the first light source 101 and the second light source 102 so that the first light L1 output from the first light source 101 is reflected by the DMD 103 and then irradiated onto the build surface S via the illumination optical system. In the second state, the rotating stage 131 arranges the first light source 101 and the second light source 102 so that the second light L2 output from the second light source 102 is reflected by the DMD 103 and then irradiated onto the build surface S via the illumination optical system.

[0091] (Operation and Effects of the Stereolithography Apparatus) The operation of the stereolithography apparatus 1C will be explained with reference to Figures 3(b) and 3(c). Figure 3(b) is a plan view showing the stereolithography apparatus 1C in the first state. Figure 3(b) is a plan view showing the stereolithography apparatus 1C in the second state.

[0092] In order to switch the state of the stereolithography apparatus 1C from the second state to the first state, the control device (not shown) operates the DMD 103 and the position change mechanism 130 as follows.

[0093] (1) Switch all micromirrors that make up the DMD103 to the OFF state.

[0094] (2) The rotating stage 131 is rotated so that the first light L1 output from the first light source 101 is incident on the reflective surface of the DMD 103 from the front, and the second light L2 output from the second light source 102 is not incident on the reflective surface of the DMD from the front.

[0095] (3) Switch the modulation pattern of the DMD103 to the first modulation pattern.

[0096] This realizes the state shown in Figure 3(b), that is, the first state in which the first light L1 output from the first light source 101 is irradiated onto the molding surface S in a first irradiation pattern corresponding to the first modulation pattern.

[0097] In the first state, the second light source 102 may be lit or unlit. When the second light source 102 is lit, the second light L2 output from the second light source 102 is reflected in a different direction from the first light L1 output from the first light source 101, and is then radiated outside the stereolithography apparatus 1C or absorbed by a light-shielding member provided inside the stereolithography apparatus 1C.

[0098] In order to switch the state of the stereolithography apparatus 1C from the first state to the second state, the control device (not shown) operates the DMD 103 and the position change mechanism 130 as follows.

[0099] (4) Switch all micromirrors that make up the DMD103 to the OFF state.

[0100] (5) The rotating stage 131 is rotated so that the second light L2 output from the second light source 102 is incident on the reflective surface of the DMD from the front, and the first light L1 output from the first light source 101 is not incident on the reflective surface of the DMD 103 from the front, and the first light source 101 and the second light source 102 are positioned accordingly.

[0101] (6) Switch the modulation pattern of the DMD103 to the second modulation pattern.

[0102] This realizes the state shown in Figure 3(c), that is, the second state in which the second light L2 output from the second light source 102 is irradiated onto the molding surface S in a second irradiation pattern corresponding to the second modulation pattern.

[0103] In the second state, the first light source 101 may be lit or unlit. When the first light source 101 is lit, the first light L1 output from the first light source 101 is reflected in a different direction from the second light L2 output from the second light source 102, and is then radiated outside the stereolithography apparatus 1C or absorbed by a light-shielding member provided inside the stereolithography apparatus 1C.

[0104] A control unit (not shown) repeats the controls described in (1) to (6) above. As a result, the stereolithography apparatus 1C alternately time-divisions irradiates the first light L1 (e.g., accelerating light) output from the first light source 101 and the second light L2 (e.g., inhibiting light) output from the second light source 102 in different irradiation patterns. The effect of the first light L1 and L2, which are alternately time-divisions irradiated in different irradiation patterns on the photocurable resin P approaches the effect of the first light L1 and L2, which are simultaneously and continuously irradiated in different irradiation patterns, as the duration of the first state and the duration of the second state are shortened.

[0105] When the first light L1 output from the first light source 101 is a accelerating light and the second light L2 output from the second light source 102 is an inhibiting light, it is preferable that the duration of the first state and the duration of the second state are 1 / 10 or less (for example, 0.1 seconds or less) of the curing time (for example, 1 second) when only the first light L1 output from the first light source 101 is continuously irradiated (for example, 1 second). This makes it possible to obtain the same effect as when the first light L1, which is an accelerating light, and the second light L2, which is an inhibiting light, are continuously irradiated simultaneously in different irradiation patterns.

[0106] For example, the irradiation pattern of the first light L1, which is a accelerating light, is set to selectively irradiate the inside of the area to be cured on the fabricated surface S with the first light L1, and the irradiation pattern of the second light L2, which is an inhibiting light, is set to selectively irradiate the outside of the area to be cured on the fabricated surface S with the second light L2. In this case, blurring of the shape of the contour of the fabricated object is less likely to occur, making it possible to fabricate an object with high precision as designed.

[0107] Furthermore, when a control device (not shown) performs the above-described controls (1) to (6), the duration of the first state is the time from when the modulation pattern of the DMD 103 is switched to the first modulation pattern in control (3) until when the modulation pattern of the DMD 103 is switched to the all-off pattern in control (4). The duration of the second state is the time from when the modulation pattern of the DMD 103 is switched to the second modulation pattern in control (6) until when the modulation pattern of the DMD 103 is switched to the all-off pattern in control (1).

[0108] The effect of the stereolithography apparatus 1C is the same as that of the stereolithography apparatus 1A. Also, similar to the stereolithography apparatus 1A, instead of a configuration in which accelerating light and inhibiting light are alternately irradiated in different patterns in time-division time, a configuration in which two types of accelerating light are alternately irradiated in different patterns in time-division time can be adopted.

[0109] (Modified Stereolithography Apparatus) A modified example of the stereolithography apparatus 1C will be described with reference to Figure 4(c). Figure 4(c) is a plan view showing the configuration of the stereolithography apparatus 1C (hereinafter referred to as "stereolithography apparatus 1C'") according to this modified example.

[0110] The stereolithography apparatus 1C' is modified by replacing the DMD 103 of the stereolithography apparatus 1C, which is a reflective spatial light modulator, with an LCOS (Liquid Crystal On Silicon) 103', which is a transmissive spatial light modulator. This replacement has resulted in a change in the arrangement of the first light source 101 and the second light source 102.

[0111] LCOS103' is composed of a matrix of liquid crystal pixels. The transmittance of each liquid crystal pixel is controlled by a control device (not shown). Light transmitted through LCOS103' has a spatial intensity distribution corresponding to the modulation pattern of LCOS103'. In other words, LCOS103' functions as a transmissive spatial light modulator. The modulation pattern of LCOS103' is the distribution of transmittance in the liquid crystal pixel group constituting LCOS103'.

[0112] The operation and effects of the stereolithography apparatus 1C' are the same as those of the stereolithography apparatus 1C, so their explanation is omitted here.

[0113] (Specific example of a structure) Using stereolithography apparatuses 1A to 1C and 1A' to 1C', it is possible to manufacture an optical diffraction element with optical computing functionality (a specific example of the "structure" described above) composed of multiple microcells whose thicknesses are set independently of each other. When signal light is incident on such an optical diffraction element, the signal light with different phases that has passed through each microcell interferes with each other, thereby performing a predetermined optical calculation. In this specification, "microcell" refers to a cell with a cell size of less than 10 μm. Also, in this specification, "cell size" refers to the square root of the cell's area. For example, if the planar shape of the microcell is a square, the cell size is the length of one side of the cell. There is no particular lower limit to the cell size, but for example, it is 1 nm.

[0114] A specific example of such an optical diffraction element is shown in Figure 5. Figure 5 is a perspective view of the optical diffraction element according to this specific example.

[0115] The optical diffraction element according to this specific example has an effective area that is a square with sides of 1.0 mm. This effective area is composed of 100 × 100 microcells arranged in a matrix. Each microcell is composed of a rectangular pillar with a square base of sides of 1 μm, formed on a substrate with a thickness of 100 μm. The height of each pillar is, for example, 0 nm, 100 nm, 200 nm, ..., 1100 nm, 1200 nm (13 steps in 100 nm increments), and is determined so that the amount of phase change of light transmitted through the microcell composed of the pillar is a predetermined value.

[0116] When optical diffraction elements are fabricated without using inhibiting light, unintended curing of the photocurable resin P can occur in regions sandwiched between tall pillars due to the cumulative effect of accelerating light. This can easily cause the thickness of each microcell to deviate from the design value, resulting in a situation where the optical diffraction element is unable to perform its intended optical computing function.

[0117] In contrast, when optical diffraction elements are fabricated using inhibiting light, unintended curing of the photocurable resin P due to the cumulative effect of accelerating light, which can occur in regions sandwiched between tall pillars, is suppressed. As a result, the thickness of each microcell is less likely to deviate from the design value, and consequently, situations in which the optical diffraction element is unable to perform its intended optical computing function become less likely.

[0118] (Summary) The stereolithography apparatus according to Embodiment 1 is characterized by comprising: a first light source that outputs a first light; a second light source that outputs a second light; a spatial light modulator that is controlled to a first modulation pattern in a first state and to a second modulation pattern different from the first modulation pattern in a second state; an optical path changing optical system that changes the optical paths of the first light and the second light so that the first light is incident on the spatial light modulator in the first state and the second light is incident on the spatial light modulator in the second state; and an irradiation optical system that, in the first state, irradiates the molding surface set in a photocurable resin with the first light, which has been spatially modulated by the spatial light modulator, in a first irradiation pattern, and in the second state, irradiates the molding surface with the second light, which has been spatially modulated by the spatial light modulator, in a second irradiation pattern different from the first irradiation pattern.

[0119] The stereolithography apparatus according to Embodiment 2 is the stereolithography apparatus according to Embodiment 1, characterized in that the second light is light whose wavelength is different from the wavelength of the first light.

[0120] The stereolithography apparatus according to embodiment 3 is the stereolithography apparatus according to embodiment 2, characterized in that the first light is an accelerating light that promotes the curing of a photocurable resin by an n-photon absorption reaction (where n is any natural number of 1 or more), and the second light is an inhibiting light that inhibits the curing of the photocurable resin.

[0121] The photopolymerization apparatus according to embodiment 4 is the photopolymerization apparatus according to embodiment 2, characterized in that the first light is an accelerating light that promotes the curing of the photocurable resin by an n-photon absorption reaction (where n is any natural number of 1 or more), and the second light is an accelerating light that promotes the curing of the photocurable resin by an m-photon absorption reaction (where m is any natural number of n+1 or more).

[0122] The stereolithography apparatus according to embodiment 5 is the stereolithography apparatus according to embodiment 3 or 4, characterized in that the duration of the first state and the duration of the second state are each 1 / 10 or less of the curing time when the photocurable resin is continuously irradiated with only the first light.

[0123] The stereolithography apparatus according to embodiment 6 is the stereolithography apparatus according to any one of embodiments 1 to 5, characterized in that the spatial light modulator is a DMD (Digital Mirror Device).

[0124] The stereolithography apparatus according to embodiment 7 is a stereolithography apparatus according to any one embodiment of embodiments 2 to 6, characterized in that the optical path changing optical system comprises: a first shutter arranged on the optical path of the first light output from the first light source and controlled to be open in the first state and closed in the second state; a second shutter arranged on the optical path of the second light output from the second light source and controlled to be closed in the first state and open in the second state; and a dichroic mirror arranged at the intersection of the optical path of the first light that has passed through the first shutter and the optical path of the second light that has passed through the second shutter, which transmits one of the first light and the second light and reflects the other, wherein the orientation of the dichroic mirror is set so that the first light or the second light reflected by the dichroic mirror and the first light or the second light transmitted through the dichroic mirror pass through a common optical path and are incident on the spatial light modulator.

[0125] The stereolithography apparatus according to embodiment 8 is the stereolithography apparatus according to embodiment 7, characterized in that the switching of the modulation pattern of the spatial light modulator is performed during the period when both the first shutter and the second shutter are in a closed state.

[0126] The stereolithography apparatus according to embodiment 9 is the stereolithography apparatus according to embodiment 7 or 8, characterized in that the first shutter and the second shutter are Pockels cells.

[0127] The stereolithography apparatus according to embodiment 10 is the stereolithography apparatus according to embodiment 7 or 8, characterized in that the first shutter and the second shutter are mechanical shutters.

[0128] The stereolithography apparatus according to embodiment 11 is a stereolithography apparatus according to any one embodiment of embodiments 1 to 6, characterized in that the optical path changing optical system is positioned at the intersection of the optical path of the first light output from the first light source and the optical path of the second light output from the second light source, and includes a movable mirror that reflects the first light output from the first light source and the second light output from the second light source, and the orientation of the movable mirror in each of the first and second states is set such that the first light reflected by the movable mirror in the first state and the second light reflected by the movable mirror in the second state pass through a common optical path and enter the spatial light modulator.

[0129] The stereolithography apparatus according to embodiment 12 is a stereolithography apparatus according to any one embodiment of embodiments 1 to 6, characterized in that, instead of the optical path changing optical system, it is equipped with a position changing mechanism that changes the positions of the first light source and the second light source so that in the first state, the first light output from the first light source is incident on the spatial light modulator, and in the second state, the second light output from the second light source is incident on the spatial light modulator, and the positions of the first light source and the second light source in each of the first and second states are set so that the first light output from the first light source in the first state and the second light output from the second light source in the second state pass through a common optical path and are incident on the spatial light modulator.

[0130] The method for manufacturing a structure according to embodiment 13 is a method for manufacturing a structure characterized by alternatingly repeating the operation of spatially modulating a first light output from a first light source using a spatial light modulator controlled to a first modulation pattern, and the operation of spatially modulating a second light output from a second light source using the spatial light modulator controlled to a second modulation pattern different from the first modulation pattern, and alternatingly irradiating the molding surface set in the photocurable resin before curing with the first light and the second light using different irradiation patterns in a time-division manner, thereby manufacturing a structure made of the photocurable resin after curing.

[0131] (Additional Notes) The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in each of the embodiments described above are also included within the technical scope of the present invention.

[0132] For example, a stereolithography apparatus equipped with N light sources, including light sources not described in the claims, and capable of taking on N states, including states not described in the claims, is also included in the technical scope of the present invention. That is, the following stereolithography apparatuses are also included in the technical scope of the present invention.

[0133] The system comprises: a first light source that outputs a first laser, a second light source that outputs a second laser, ..., an nth light source that outputs an nth laser; a spatial light modulator that is controlled to a first modulation pattern in a first state, controlled to a second modulation pattern in a second state, ..., and controlled to an nth modulation pattern in an nth state; optical path changing means for changing the optical paths of the first light output from the first light source, the second light output from the second light source, ..., and the nth light output from the nth light source, such that in the first state the first light is incident on the spatial light modulator, in the second state the second light is incident on the spatial light modulator, ..., and in the nth state the nth light is incident on the spatial light modulator; and an irradiation optical system that, in the first state, irradiates the molding surface set in a photocurable resin with the first light spatially modulated by the spatial light modulator in a first irradiation pattern, and in the second state, irradiates the molding surface with the second light spatially modulated by the spatial light modulator in a second irradiation pattern. A stereolithography apparatus characterized in that the first modulation pattern, the second modulation pattern, ..., n modulation patterns include at least two different modulation patterns, and the first irradiation pattern, the second irradiation pattern, ..., n irradiation patterns include at least two different irradiation patterns.

[0134] 1A, 1B, 1C, 1A', 1B'1C' Stereolithography apparatus 100 Container 101 First light source 102 Second light source 103 DMD (Spatial Light Modulator) 103' LCOS (Spatial Light Modulator) 104 Imaging lens 105 Aperture diaphragm 106 Beam splitter 107 First objective lens 108 Second objective lens 109 Image sensor 110 Optical path changing optical system 111 First shutter 112 Second shutter 113 Dichroic mirror 114 Folding mirror 120 Optical path changing optical system 121 Movable mirror 130 Position changing mechanism 131 Rotating stage

Claims

1. A photopolymerization apparatus comprising: a first light source that outputs a first light; a second light source that outputs a second light; a spatial light modulator that is controlled to a first modulation pattern in a first state and to a second modulation pattern different from the first modulation pattern in a second state; an optical path changing optical system that changes the optical paths of the first light output from the first light source and the second light output from the second light source so that the first light is incident on the spatial light modulator in the first state and the second light is incident on the spatial light modulator in the second state; and an irradiation optical system that, in the first state, irradiates the molding surface set in a photocurable resin with the first light spatially modulated by the spatial light modulator in a first irradiation pattern, and in the second state, irradiates the molding surface with the second light spatially modulated by the spatial light modulator in a second irradiation pattern different from the first irradiation pattern.

2. The stereolithography apparatus according to claim 1, characterized in that the second light has a wavelength different from that of the first light.

3. The photopolymerization apparatus according to claim 2, characterized in that the first light is an accelerating light that promotes the curing of a photocurable resin by an n-photon absorption reaction (where n is any natural number of 1 or more), and the second light is an inhibiting light that inhibits the curing of the photocurable resin.

4. The photopolymerization apparatus according to claim 2, characterized in that the first light is a facilitating light that promotes the curing of the photocurable resin by an n-photon absorption reaction (where n is any natural number of 1 or more), and the second light is a facilitating light that promotes the curing of the photocurable resin by an m-photon absorption reaction (where m is any natural number of n+1 or more).

5. The stereolithography apparatus according to claim 3 or 4, characterized in that the duration of the first state and the duration of the second state are each 1 / 10 or less of the curing time when the photocurable resin is continuously irradiated with only the first light.

6. The stereolithography apparatus according to any one of claims 1 to 5, characterized in that the spatial light modulator is a DMD (Digital Mirror Device).

7. The optical path changing optical system comprises: a first shutter positioned on the optical path of the first light output from the first light source, controlled to be open in the first state and controlled to be closed in the second state; a second shutter positioned on the optical path of the second light output from the second light source, controlled to be closed in the first state and controlled to be open in the second state; and a dichroic mirror positioned at the intersection of the optical path of the first light that has passed through the first shutter and the optical path of the second light that has passed through the second shutter, transmitting one of the first light and the second light and reflecting the other, wherein the orientation of the dichroic mirror is set such that the first light or the second light reflected by the dichroic mirror and the first light or the second light transmitted through the dichroic mirror pass through a common optical path and are incident on the spatial light modulator, characterized in that the stereolithography apparatus according to any one of claims 2 to 6.

8. The stereolithography apparatus according to claim 7, characterized in that the switching of the modulation pattern of the spatial light modulator is performed during a period when both the first shutter and the second shutter are in a closed state.

9. The stereolithography apparatus according to claim 7 or 8, characterized in that the first shutter and the second shutter are composed of Pockels cells.

10. The stereolithography apparatus according to claim 7 or 8, characterized in that the first shutter and the second shutter are composed of mechanical shutters.

11. The optical path changing optical system is positioned at the intersection of the optical path of the first light output from the first light source and the optical path of the second light output from the second light source, and includes a movable mirror that reflects the first light output from the first light source and the second light output from the second light source, wherein the orientation of the movable mirror in each of the first and second states is set such that the first light reflected by the movable mirror in the first state and the second light reflected by the movable mirror in the second state pass through a common optical path and enter the spatial light modulator, characterized in that the stereolithography apparatus according to any one of claims 1 to 6.

12. The stereolithography apparatus according to any one of claims 1 to 6, wherein, in place of the optical path changing optical system, the apparatus is provided with a position changing mechanism that changes the positions of the first light source and the second light source so that in the first state, the first light output from the first light source is incident on the spatial light modulator, and in the second state, the second light output from the second light source is incident on the spatial light modulator, and the positions of the first light source and the second light source in each of the first and second states are set so that the first light output from the first light source in the first state and the second light output from the second light source in the second state pass through a common optical path and are incident on the spatial light modulator.

13. A method for manufacturing a structure, characterized by alternating between the operation of spatially modulating a first light output from a first light source using a spatial light modulator controlled to a first modulation pattern, and the operation of spatially modulating a second light output from a second light source using the spatial light modulator controlled to a second modulation pattern different from the first modulation pattern, and alternatingly irradiating the molding surface set in the photocurable resin before curing with the first light and the second light in different irradiation patterns in a time-division manner, thereby manufacturing a structure made of the photocurable resin after curing.

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