METHOD FOR MANUFACTURING STEREOLITHOGRAPHICALLY FABRICATED OBJECT

A method for manufacturing a stereolithographically fabricated object includes separately irradiating, with light, respective n regions R1 to Rn of a photo-curable resin, where n is an integer of not less than 2. An overlap area of the region Ri overlaps a part of the region Rj, where i is an integer that satisfies 1≤i≤n and j is an integer that satisfies 1≤j≤n and j≠i. The photo-curable resin is cured in a part or an entirety of the overlap area by irradiating the region Ri with the light.

BACKGROUND

Technical Field

The present invention relates to methods for manufacturing stereolithographically fabricated objects.

Description of the Related Art

Stereolithography is an aspect of the optical fabrication method, and there are two types of stereolithography: a scanning type stereolithography in which a galvanoscanner is used to perform scanning by using laser light, and a projection type stereolithography in which a digital micromirror device (DMD) is used to project light that has been subjected to patterning. In the projection type, light incident on the DMD may be that emitted by a laser light source, or may be that emitted by a lamp typified by a mercury lamp. For example, Non-Patent Literature 1 discloses inFIG.5an optical system of the projection type stereolithography that uses laser light having a wavelength λ of 405 nm.

The optical system of Non-Patent Literature 1 collimates laser light and irradiates, with the collimated laser light, a digital micromirror device (DMD). The orientation of each of mirrors constituting the DMD is controlled so that the intensity distribution in the irradiation region of the laser light forms a desired pattern. Thus, when the laser light is reflected by this DMD, the intensity distribution in the irradiation region of the laser light is converted from the substantially uniform distribution to a distribution corresponding to the desired pattern. The laser light subjected to the patterning and having the intensity distribution corresponding to the desired pattern is projected, by means of an objective having a focal length f of 45 mm, on a sample platform with the surface covered by a layer of a photo-curable resin. This makes the layer of the photo-curable resin on the sample platform irradiated with the laser light corresponding to the desired pattern, to form a stereolithographically fabricated object having the desired pattern.

Here, irrespective of whether the scanning type or the projection type of stereolithography is used, the minimum dimension of a photo-curable resin to be cured by exposure to light is depending on the minimum dimension of light with which the photo-curable resin is irradiated. Further, the minimum dimension of light with which the photo-curable resin is irradiated is depending on the resolution δ of the irradiation optical system that irradiates the sample platform with light. There are some ways of thinking about the resolution δ: the Rayleigh's resolution, the Abbe's resolution, and the Hopkins' resolution. Using the wavelength λ and the numerical aperture NA, the Rayleigh's resolution is represented by δ=0.61λ/NA, the Abbe's resolution is represented by δ=λ/NA, and the Hopkins' resolution is represented by δ=κλ/NA. Here, κ, included in the formula of the Hopkins' resolution, is a constant that is defined depending on the state of illumination, and the minimum value of κ is 0.58.

Thus, when the stereolithography is used, it is not possible to manufacture a stereolithographically fabricated object including a pattern having a smaller dimension than the resolution δ of the irradiation optical system.

SUMMARY

One or more embodiments manufacture a stereolithographically fabricated object including a fine pattern, as compared to the resolution of an irradiation optical system.

A method for manufacturing a stereolithographically fabricated object in accordance with one or more embodiments includes first to n-th steps of irradiating, with light, respective n regions R1to Rn(n is an integer of not less than 2) of a photo-curable resin, wherein part (example of an overlap area) of a region Ri(i is an integer that satisfies 1≤i≤n) coincides with part of a region Rj(j is an integer that satisfies 1≤j≤n and j≠i), and the photo-curable resin is cured in a common region that is part or whole of an overlap (example of the overlap area) formed when the region Ri, which is irradiated with the light in an i-th step, overlaps the region Rj.

According to the method for manufacturing a stereolithographically fabricated object in accordance with one or more embodiments, it is possible to manufacture stereolithographically fabricated object including a fine pattern, as compared to the resolution δ of the irradiation optical system.

DESCRIPTION OF THE EMBODIMENTS

Before describing a method of manufacturing a stereolithographically fabricated object in accordance with one or more embodiments, the following will describe, with reference toFIG.1, the configurations of stereolithography devices10and20with which the present manufacturing method can be suitably performed. (a) and (b) ofFIG.1are schematic views of the stereolithography devices10and20, respectively.

The stereolithography device10includes a digital micromirror device (DMD)11, a lens12, a container13, a sample platform14, and a stage15(see (a) ofFIG.1). Although not illustrated in (a) ofFIG.1, the stereolithography device10also includes a laser device that produces light L to which a photo-curable resin R is exposed. Similarly to the stereolithography device depicted in FIG. 5 of Non-Patent Literature 1, the stereolithography device10is an example of projection stereolithography devices.

According to one or more embodiments, the laser device includes a semiconductor module configured to produce light L having a wavelength λ of 405 nm. The light L emitted from the laser device undergoes conversion from diverging light to collimated light, which is illustrated in (a) ofFIG.1, by means of a collimating optical system including a lens. Here, (a) ofFIG.1depicts the central axis of a bundle of rays of light L as an optical axis AL. The optical axis ALcorresponds to an optical path through which a chief ray of the light L travels.

In (a) ofFIG.1, a vertically upward direction orthogonal to the surface of a liquid photo-curable resin R (i.e., the horizontal plane) is defined as a positive z-axial direction, a propagation direction of light L before being incident on the DMD11is defined as a positive x-axis direction, and a direction constituting the right-handed orthogonal coordinate system with the positive x-axial direction and the positive z-axial direction is defined as a positive y-axial direction.

The DMD11includes a plurality of mirrors arranged in a matrix pattern. The orientation of each mirror is controlled by a computer, and each mirror is controlled to face in either a first direction or a second direction. When a mirror faces in the first direction, light L reflects off the mirror and propagates in the negative z-axial direction. This state is referred to as the ON state. When a mirror faces in the second direction, light L reflects off the mirror and propagates in another direction different from the negative z-axial direction. This state is referred to as the OFF state. Thus, by selecting at least one of the mirrors arranged in the matrix pattern and by changing the state of the selected one or ones to the ON state, the DMD11can form a pattern of the intensity distribution in the irradiation region of reflected light L propagating in the negative z-axial direction.

The light L subjected to the patterning with the DMD11so as to have an intensity distribution of a desired pattern is then projected, by means of the lens12, on a main face141of the sample platform14located below a layer of the photo-curable resin R. The lens12functions as an objective. The sample platform14will be described later.

In the stereolithography device10, the laser device, the collimating optical system, the DMD11, and the lens12constitute an irradiation optical system configured to irradiate the photo-curable resin R with light L. It is preferable that the irradiation optical system be adjusted to form the finest possible pattern of light L projected on the main face141, as described later. That is, it is preferable that the irradiation optical system be adjusted so as to achieve the highest possible resolution.

It should be noted that there are some ways of thinking about the resolution δ of the irradiation optical system: the Rayleigh's resolution, the Abbe's resolution, and the Hopkins' resolution. When the wavelength λ of 405 nm and the numerical aperture NA of 1 are employed, the Rayleigh's resolution and the Abbe's resolution are 247 nm and 405 nm, respectively. The Hopkins' resolution is 235 nm when κ=0.58, which is the minimum value.

Below the DMD11, the container13, the sample platform14, and the stage15are disposed.

The stage15is a three-axis stage that is capable of moving the table in a translational manner in the x-, y-, and z-axial directions. The stage15has a resolution on the order of nanometers, to precisely control the positions of the container13and the sample platform14, as described later. Examples of the xyz stage having a resolution on the order of nanometers include an xyz stage that is provided with a piezoactuator for use in driving of the table in each axial direction. Such an xyz stage may have a resolution of about 5 nm, for example. It should be noted that (a) ofFIG.1depicts the stage15by showing only the table thereof. It should be noted that the stage15is controlled by a computer. To the table of the stage15, a z-axis stage, described later, is secured.

On the table of the stage15, the container13is situated. Inside the container13, the sample platform14and a photo-curable resin R are provided.

The sample platform14is connected to the z-axis stage outside the container13. The z-axis stage is configured to move translationally in the z-axial direction. As described above, the z-axis stage is secured to the table of the stage15. Thus, when the table of the stage15is moved, the container13, the z-axis stage, and the sample platform14are moved in synchronization (moved in an integrated manner). That is, the relative position of the sample platform14with respect to the container13in the xy plane is fixed. It should be noted that the z-axis stage is controlled by a computer.

A liquid photo-curable resin R is cured into a solid when being irradiated with light L of a dose that exceeds a threshold. The photo-curable resin R may be selected, depending on the purpose of use, from commercially available photo-curable resins for use in optical fabrication.

The stereolithography device10uses the free surface technique in which the free surface of a photo-curable resin R is irradiated with light L in a vertically downward direction. Thus, the position of the sample platform14on the z-axis is controlled with the z-axis stage so that the main face141, which is one of a pair of the main faces and is located on the positive side of the z-axis, is located slightly lower than the free surface. This forms, on the main face141, a layer of the photo-curable resin R having a predetermined thickness (e.g., not less than 2 μm and not more than 5 μm).

In the stereolithography device10, the container13, the sample platform14, the stage15, and the z-axis stage constitute a photo-curable resin holding system configured to hold the photo-curable resin R.

As described above, light L subjected to the patterning with the DMD11is projected, by means of the lens12, on the main face141that is located below the layer of the photo-curable resin R. Thus, the pattern formed with the DMD11by means of the mirrors in the ON state is transferred on the layer of the photo-curable resin R on the main face141. This creates a stereolithographically fabricated object that has a desired pattern, on the main face141.

The stereolithography device20includes a galvanoscanner21, a lens22, a container13, a sample platform14, and a stage15(see (b) ofFIG.1). The stereolithography device20is an example of scanning stereolithography devices.

The container13, the sample platform14, and the stage15are identical to those included in the stereolithography device10.

Although not illustrated in (b) ofFIG.1, the stereolithography device20also includes a laser device that produces light L to which a photo-curable resin R is exposed. This laser device is identical to that included in the stereolithography device10.

Collimated light L emitted from the laser device enters the galvanoscanner21. The galvanoscanner21includes two mirrors, and two motors each configured to control the orientation of a corresponding one of the mirrors. The galvanoscanner21is controlled by a computer. By adjusting the orientations of the two mirrors, the galvanoscanner21can perform scanning, using light L with which a main face141is irradiated.

In the stereolithography device20, the laser device, the collimating optical system, and the galvanoscanner21constitute an irradiation optical system configured to irradiate the photo-curable resin R with light L.

The lens22functions as an objective, similarly to the lens12.

The following will describe a method for manufacturing a stereolithographically fabricated object in accordance with one or more embodiments, with reference toFIG.2. (a) and (b) ofFIG.2are schematic views illustrating a region R1in a first step and a region R2in a second step, respectively, the first and second steps being included in the present manufacturing method. (c) ofFIG.2is a schematic view illustrating a common region Rcin which a photo-curable resin R is cured because the photo-curable resin R has been subjected to both the first and second steps. Here, the upper diagrams of (a) to (c) ofFIG.2are plan views of the regions when the main face141of the sample platform14included in the stereolithography device10is viewed from above. The lower diagrams of (a) to (c) ofFIG.2are graphs each showing the dose on the line segment AB, illustrated in (a) ofFIG.2. It should be noted that a layer of the photo-curable resin R is formed on the main face141.

<Case in which Projection Stereolithography Device is Used>

Here, the following will describe a case in which the projection stereolithography device10is used in performing the present manufacturing method. Light L has a wavelength λ of 405 nm, and the lens12has a numerical aperture NA of 1. In this case, the Rayleigh's resolution and the Abbe's resolution are 247 nm and 405 nm, respectively. The Hopkins' resolution is 235 nm when κ=0.58, which is the minimum value.

The present manufacturing method includes a first step illustrated in (a) ofFIG.2and a second step illustrated in (b) ofFIG.2. That is, the present manufacturing method is an example of a case of n=2 in the manufacturing method in accordance with one or more embodiments. However, according to the manufacturing method in accordance with one or more embodiments, n is not limited to 2, and n only needs to be an integer of not less than 2.

The first step is a step of irradiating, with light L, the region R1of a photo-curable resin R on the main face141. According to one or more embodiments, the region R1is a square having a side length L of 405 nm. For example, a first variation, which will be described later with reference toFIG.3, employs n=3.

The second step is a step of irradiating, with light L, the region R2of the photo-curable resin R on the main face141. In one or more embodiments, the region R2is a square having a side length L of 405 nm, similarly to the region R1.

The present manufacturing method uses the stereolithography device10that includes a single DMD11, so that the first step and the second step are performed in turn at different timings. In addition, in one or more embodiments, the dose of light L in the first step and that in the second step are the same, and are dose Vd.

The region R2is obtained by translationally moving the region R1by L/2 in the positive x-axial direction. Thus, the region R1and the region R2overlap. In the present manufacturing method, since n=2, the whole overlap between the region R1and the region R2forms a common region Rc. The common region Rcis a rectangle having a length in the x-axial direction of 202.5 nm, which corresponds to L/2, and a length in the y-axial direction of 405 nm.

The dose Vdof light L in the first and second steps may be set to any desired value in accordance with the intensity of light L and the exposure time. In the present manufacturing method, the photo-curable resin R in the common region Rc, described later, of the photo-curable resin R in the regions R1and R2is cured, and the photo-curable resin R is not cured outside the common region Rc. Thus, when a threshold at which the photo-curable resin R is cured is assumed to be threshold Vth, the dose Vdmay be set to satisfy both Vth<2Vdand Vd<Vth, that is, Vth/2<Vd<Vth. In the present manufacturing method, the dose Vdof light L in the first step is set so that Vd=2Vth/3 (see (c) ofFIG.2).

Dose 2Vdin the common region Rcis thus 2Vd=4Vth/3. On the other hand, the dose Vdin the remaining region in the regions R1and R2, which is other than the common region Rc, is thus Vd=2Vth/3. Thus, only the photo-curable resin R in the common region Rcis cured.

In this way, in the present manufacturing method, it is possible to manufacture a stereolithographically fabricated object including a fine pattern, as compared to the resolution δ (e.g., 235 nm) of the irradiation optical system.

When the stereolithography device10illustrated in (a) ofFIG.1is used in performing the present manufacturing method, both the regions R1and R2are formed by means of the single DMD11. Thus, the first step and the second step are performed in turn at different timings. Further, the positions of the regions R1and R2of the photo-curable resin R (seeFIG.2) may be determined in accordance with the arrangement of part of the irradiation optical system (e.g., at least one of the DMD11and the lens12), which is an optical system configured to irradiate the photo-curable resin R with light L. Further, the positions of the regions R1and R2of the photo-curable resin R may be determined in accordance with both the position of the sample platform14irradiated with light L and the position of the container13. In this case, the sample platform14and the container13may be configured to be moved in synchronization (moved in an integrated manner). Further, the present manufacturing method is more effective in a case in which the minimum dimension (L/2 in (a) ofFIG.2) of the pattern included in the common region Rcis not more than the resolution δ (e.g., 235 nm) of the irradiation optical system, which is the optical system configured to irradiate the photo-curable resin R with light L. That is, the present manufacturing method is more effective in a case in which, in the photo-curable resin R, an amount of translational movement from the region R1to the region R2is not more than the resolution δ.

It should be noted that, in the manufacturing method in accordance with one or more embodiments, n is not limited to 2, and n of an integer of not less than 2 may be employed. In this case, the manufacturing method in accordance with one or more embodiments includes first to n-th steps of irradiating, with light, respective n regions R1to Rnof the photo-curable resin R. Part of a region Ri(i is an integer that satisfies 1≤i≤n) coincides with part of a region Rj(j is an integer that satisfies 1≤j≤n and j≠i). With this configuration, the manufacturing method in accordance with one or more embodiments causes the photo-curable resin R to be cured in a common region that is part or whole of the overlap formed when the region Riirradiated with light L in an i-th step overlaps the region Rj. Here, the area of the part of the region Rimay be greater than 20% and less than 100% with respect to the whole area of the region Ri. Further, the area of the part of the region Rjmay be greater than 20% and less than 100% with respect to the whole area of the region Rj.

The following will describe a first variation of the manufacturing method illustrated inFIG.2, with reference toFIG.3. (a) to (c) ofFIG.3are schematic views illustrating a region R1in a first step, a region R2in a second step, and a region R3in a third step, respectively, the first to third steps being included in the manufacturing method in accordance with the first variation. (d) ofFIG.3is a schematic view illustrating a common region Rcin which a photo-curable resin R is cured because the photo-curable resin R has been subjected to all the first to third steps. Similarly to the case depicted inFIG.2, the upper diagrams of (a) to (d) ofFIG.3are plan views of the regions when the main face141of the sample platform14included in the stereolithography device20is viewed from above. The lower diagrams of (a) to (d) ofFIG.3are graphs each showing the dose on the line segment CD, illustrated in (d) ofFIG.3.

The first variation is an example of a case of n=3 in the manufacturing method in accordance with one or more embodiments. Thus, as illustrated in (a), (b), and (c) ofFIG.3, the first variation includes the first step, the second step, and the third step.

In i-th steps (i is an integer that satisfies 1≤i≤3), respective regions Riare irradiated with light L. Similarly to the case of the manufacturing method illustrated inFIG.2, the region Riis a square having a side length L of 405 nm.

Regions Ri+1are obtained by translationally moving the regions Riby L/3 in both the positive x-axial direction and the negative y-axial direction. Thus, the regions Rioverlap each other. Hereinbelow, an overlap between at least two of the regions R1to R3is referred to as a first common region Rc1, and an overlap between all of the regions R1to R3is referred to as a second common region Rc2.

The first common region Rc1is the whole overlap formed when the region Riirradiated with light L in the corresponding i-th step overlaps the region Rj(j is an integer that satisfies 1≤j≤n and j≠i). The first common region Rc1has a shape of overlapping two squares each having a side length of 270 nm.

The second common region Rc2is part of the entire overlap formed when the region Riirradiated with light L in the corresponding i-th step overlaps the region Rj. In the first common region Rc1, the width of the narrowest portion is 191 nm. Further, the second common region Rc2is a square having a side length of 135 nm.

In the first variation, the dose of light L is the same in every i-th step, and is dose Vd.

A threshold at which the photo-curable resin R in the first common region Rc1is cured is assumed to be threshold Vth1. In this case, the dose Vdonly needs to be set to satisfy both Vth1<2Vdand Vd<Vth1, that is, Vth1/2<Vd<Vth1.

Further, a threshold at which the photo-curable resin R in the second common region Rc2is cured is assumed to be threshold Vth2. In this case, the dose Vdonly needs to be set to satisfy both Vth2<3Vdand 2Vd<Vth2, that is, Vth2/3<Vd<Vth2/2.

According to this first variation, it is possible to selectively cure the photo-curable resin R in the first common region Rc1or the second common region Rc2by controlling the dose Vdin each i-th step. Thus, according to the first variation, it is possible to manufacture a stereolithographically fabricated object including a fine pattern, as compared to the resolution δ (e.g., 235 nm) of the irradiation optical system.

<Second Variation: Case in which Scanning Stereolithography Device is Used>

The following will describe a second variation of the manufacturing method illustrated inFIG.2, with reference toFIG.4. (a) and (b) ofFIG.4are schematic views illustrating a region R1in a first step and a region R2in a second step, respectively, the first and second steps being included in the manufacturing method in accordance with the second variation. (c) ofFIG.4is a schematic view illustrating a common region Rcin which a photo-curable resin R is cured because the photo-curable resin R has been subjected to both the first and second steps. Here, the upper diagrams of (a) to (c) ofFIG.4are plan views of the regions when the main face141of the sample platform14included in the stereolithography device20is viewed from above. The lower diagrams of (a) to (c) of the figure are graphs each showing the dose on the line segment EF, illustrated in (a) ofFIG.4. It should be noted that a layer of the photo-curable resin R is formed on the main face141.

The following will describe a case in which a scanning stereolithography device20is used, in the second variation, in performing the present manufacturing method, instead of the projection stereolithography device10. Light L has a wavelength λ of 405 nm, and the lens12has a numerical aperture NA of 1. In this case, the Rayleigh's resolution and the Abbe's resolution are 247 nm and 405 nm, respectively. The Hopkins' resolution is 235 nm when κ=0.58, which is the minimum value.

The second variation includes: the first step in which the photo-curable resin R in the region R1is irradiated with light; and the second step in which the photo-curable resin R in the region R2is irradiated with light. According to the second variation, the first step and the second step are performed in turn at different timings because the scanning stereolithography device20is used.

In the second variation, a region Ri(i is an integer that satisfies 1≤i≤n) overlaps a region Rj(j is an integer that satisfies 1≤j≤n and j≠i). Specifically, the region R1and the region R2overlap. With this configuration, in the second variation, the photo-curable resin R in a common region Rcthat is the overlap between the region R1and the region R2is cured. This configuration in the second variation is identical to that in the manufacturing method illustrated inFIG.2.

A difference between the second variation and the manufacturing method illustrated inFIG.2is how the photo-curable resin R is irradiated with light L. In the second variation, the galvanoscanner21illustrated in (b) ofFIG.1is used in scanning in which light L in the form of laser light is used, to transfer the patterns of the regions R1and R2on the photo-curable resin R.

In the second variation, each of the regions R1and R2is a ring-shaped region having a square outer periphery (see (a) and (b) ofFIG.4). Here, each of the regions R1and R2has an outer peripheral side length of 2.46 μm, and a width W of the ring portion of 405 nm. The region R2is obtained by translationally moving the region R1by W/2 in both the positive x-axial direction and the negative y-axial direction.

Performing both the first and second steps forms the common region Rcthat is the whole overlap between the regions R1and R2. Similarly to the regions R1and R2, the common region Rcis a ring-shaped region having a square outer periphery. The outer peripheral side length of the common region Rcis shorter than those of the regions R1and R2by W/2, and most part of the ring portion has a width of 202.5 nm, which corresponds to W/2.

In this way, in the second variation, a stereolithographically fabricated object including a fine pattern, as compared to the resolution δ (e.g., 235 nm) of the irradiation optical system, can also be manufactured by the use of the scanning stereolithography device20.

The following will describe a stereolithography device10A, which is a variation of the stereolithography device10illustrated in (a) ofFIG.1, with reference toFIG.5.FIG.5is a schematic view illustrating the stereolithography device10A.

The stereolithography device10includes the DMD11as a means for patterning light L. Thus, in the manufacturing method illustrated inFIG.2, the DMD11is controlled to irradiate, with light L, the regions R1and R2in turn in corresponding one of the first and second steps. Thus, the manufacturing method illustrated inFIG.2(case of n=2) employs a configuration in which the first and second steps are performed in turn at different timings. This also applies to the manufacturing method illustrated inFIG.3(case of n=3).

In contrast, the stereolithography device10A employs n=3, and includes, as the means for patterning light L, three DMDs11A1,11A2, and11A3, the number of which is equal to n (seeFIG.5). Each DMD11Ai is an example of an i-th digital micromirror device Di. Further, to cause separate rays of light to be incident on the respective DMDs11Ai (i is an integer that satisfies 1≤i≤3), the stereolithography device10A includes three laser devices (not illustrated inFIG.5), the number of which is equal to n. Here, FIG. depicts optical axes ALi, each of which is the central axis of a corresponding bundle of rays, and each optical axis ALirepresents light that corresponds to the DMD11Ai.

Thus, each DMD11Ai reflects light that has been transmitted along the optical axis ALi, forming the pattern of the corresponding region Ri. In this way, the stereolithography device10A includes the irradiation optical systems the number of which is set to be equal to n (3, in the present variation). This enables the stereolithography device10A to perform an i-th step at a timing which is identical to a timing of another i-th step.

The light that has been subjected to the patterning of the intensity distribution to form a desired pattern with the corresponding DMD11Ai is projected, by means of a lens12A, on a main face141of a sample platform14located below a layer of a photo-curable resin R. The lens12A functions as an objective, similarly to the lens12illustrated in (a) ofFIG.1.

Further, in the stereolithography device10A, on an optical path extending from each DMD11Ai to the photo-curable resin R, a lens16icorresponding to the DMD11Ai is disposed. The lenses16iare examples of lenses Mi. Here, in the present variation, each lens16iis disposed on the corresponding optical path in a section between the lens12A and the photo-curable resin R. Here, as the lenses16i, used is a microlens array16in which appropriately arranged multiple microlenses are integrated.

Among the DMDs11Ai, the DMD11A2is arranged to face in the same direction as that the DMD11of the stereolithography device10faces. The DMD11A2causes the layer of the photo-curable resin R in the region R2to be irradiated with light, the layer being formed on the main face141of the sample platform14(see (b) ofFIG.3).

The orientation of the DMD11A1is adjusted so that the photo-curable resin R in the region R1(see (a) ofFIG.3) is irradiated with light. Further, the orientation of the DMD11A3is adjusted so that the photo-curable resin R in the region R3(see (c) ofFIG.3) is irradiated with light.

Using the stereolithography device10A thus configured forms the regions Riby means of the respective DMDs11Ai (which is an example of the i-th digital micromirror devices Di). In this case, it is preferable that an i-th step be performed at a timing which is identical to a timing of another i-th step.

The stereolithography device10A can be obtained by modifying the stereolithography device10illustrated in (a) ofFIG.1so as to change the number of the irradiation optical systems to a number equal to n. Similarly, by modifying the stereolithography device20illustrated in (b) ofFIG.1so as to change the number of the irradiation optical systems to a number equal to n, it is possible to perform an i-th step at a timing which is identical to a timing of another i-th step even when the scanning stereolithography device is used in performing the manufacturing method in accordance with one or more embodiments.

Aspects of one or more embodiments can also be expressed as follows:

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 1 of one or more embodiments, includes first to n-th steps of irradiating, with light, respective n regions R1to Rn(n is an integer of not less than 2) of a photo-curable resin, wherein part of a region Ri(i is an integer that satisfies 1≤i≤n) coincides with part of a region Rj(j is an integer that satisfies 1≤j≤n and j≠i), and the photo-curable resin is cured in a common region that is part or whole of an overlap formed when the region Ri, which is irradiated with the light in an i-th step, overlaps the region Rj.

With this configuration, since the common region that is part or whole of the overlap between the region Riand the region Rjis cured, it is possible to manufacture a stereolithographically fabricated object including a fine pattern, as compared to the resolution of the irradiation optical system.

Further, a method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 2 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with the Aspect 1, a configuration in which the region Riis formed by a corresponding i-th digital micromirror device Di.

With this configuration, it is possible to freely determine the timing at which the i-th step is performed.

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 3 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with the Aspect 2, a configuration in which, on an optical path extending from each digital micromirror device Dito the photo-curable resin, a lens Micorresponding to the digital micromirror device Diis disposed.

With this configuration, it is possible to reliably form an image of the region Riat a predetermined position when the plurality of i-th digital micromirror devices Diare used to form images of the respective regions Ri.

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 4 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with the Aspect 2 or 3, a configuration in which the i-th step is performed at a timing which is identical to a timing of another i-th step.

With this configuration, since the regions Riare exposed to light at once, it is possible to prevent the regions Rifrom being displaced owing to a time-dependent factor. It is also possible to shorten the time required for performing stereolithography.

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 5 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with the Aspect 1, a configuration in which the region Riis formed by means of a single digital micromirror device, and the i-th step is performed at a timing which is different from a timing of another i-th step.

With this configuration, it is possible to form the region Riwithout using a plurality of digital micromirror devices. Thus, it is possible to perform the present manufacturing method by using such a simple irradiation optical system.

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 6 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with the Aspect 5, a configuration in which a position of the region Riof the photo-curable resin is determined in accordance with an arrangement of part of an irradiation optical system that is an optical system configured to irradiate the photo-curable resin with the light.

With this configuration, it is possible to control the position of the region Riby controlling the position of the part of the irradiation optical system. Thus, it is possible to perform the present manufacturing method by using the irradiation optical system of the existing projection stereolithography.

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 7 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with the Aspect 5 or 6, a configuration in which a position of the region Riof the photo-curable resin is determined in accordance with both a position of a sample platform irradiated with the light and a position of a container configured to hold the photo-curable resin, and the sample platform and the container are moved in synchronization.

With this configuration, it is possible to control the position of the region Riby controlling the positions of the sample platform and the container, which are move in synchronization (moved in an integrated manner). Thus, it is possible to perform the present manufacturing method by using the irradiation optical system of the existing projection stereolithography.

A method for manufacturing a stereolithographically fabricated object in accordance with an Aspect 8 of one or more embodiments, employs, in addition to the configuration of the method of manufacturing a stereolithographically fabricated object in accordance with any one of the Aspects 1 to 7, a configuration in which a minimum dimension of a pattern included in the common region is less than a resolution of an irradiation optical system that is an optical system configured to irradiate the photo-curable resin with light.

Therefore, the method for manufacturing a stereolithographically fabricated object in accordance with one or more embodiments is more effective in a case in which the minimum dimension of the pattern included in the common region is less than the resolution of the irradiation optical system, which is the optical system configured to irradiate the photo-curable resin with light.

SUPPLEMENTARY NOTES

REFERENCE SIGNS LIST