JP2019077118A - Optical molding apparatus - Google Patents

Abstract

To provide an optical molding apparatus capable of realizing good shaping accuracy with a simple configuration.SOLUTION: An optical molding apparatus 100 has a container 201 having a light transmitting portion and holding liquid photocurable resin RA, a projection optical system 255 for irradiating the photocurable resin RA with light through a translucent part 212, a control unit 300 that controls light irradiation based on each of a plurality of two-dimensional shape data obtained from three-dimensional shape data, and a movable member 202 for moving a curing portion WA which receives and cures light of the photocurable resin RA in a direction away from the translucent part 212. The translucent 212 has positive refractive power.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical shaping apparatus for curing a photocurable resin to form a three-dimensional object.

  By acquiring data of each cross-sectional shape (two-dimensional shape data) generated from three-dimensional shape data indicating the shape of a three-dimensional object, and sequentially forming a shaping layer having a shape corresponding to each of the two-dimensional shape data There is known an optical shaping apparatus capable of obtaining a three-dimensional object (shaped object).

  Patent Document 1 discloses that the light modulated by the light modulation element having a plurality of pixels according to the two-dimensional shape data is irradiated to the liquid photocurable resin by the projection optical system, whereby the entire one modeling layer is obtained. An optical shaping apparatus capable of simultaneously curing is described.

JP, 2015-016610, A

  However, since the optical shaping apparatus described in Patent Document 1 uses a plurality of light modulation elements and projection optical systems, the entire apparatus becomes large and complicated. On the other hand, when only one light modulation element and one projection optical system are used, if the light is irradiated to a wide area of the light curing resin simultaneously at the same time, the incident angle of the off-axis light to the light curing resin becomes large. . Therefore, the position of the end of the shaping layer formed by the off-axis light beam deviates from the design value, and it becomes difficult to obtain good shaping accuracy.

  An object of this invention is to provide the optical shaping apparatus which can implement | achieve favorable modeling accuracy by simple structure.

  An optical shaping apparatus as one aspect of the present invention for achieving the above object has a light transmitting portion, and a container for holding a liquid photocurable resin, and the photocurable property through the light transmitting portion. A control unit for controlling the irradiation of the light based on each of a plurality of two-dimensional shape data obtained from the projection optical system for irradiating the light to the resin, and a plurality of two-dimensional shape data obtained from the three-dimensional shape data And a moving member for moving a cured portion which has been received and cured in a direction away from the light transmitting portion, wherein the light transmitting portion has a positive refractive power.

  According to the present invention, it is possible to provide an optical shaping apparatus capable of realizing good modeling accuracy with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS The principal part schematic of the optical shaping apparatus which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The principal part schematic of the modeling unit which concerns on Example 1 of this invention. FIG. 1 is a schematic view of a main part of an image forming element according to a first embodiment. The figure which shows the vicinity of the light transmission board which concerns on Example 1 and a comparative example. The principal part schematic of the modeling unit which concerns on Example 2 of this invention. The figure which shows the vicinity of the light transmission board which concerns on Example 2 and a comparative example. The principal part schematic of the modeling unit which concerns on the modification of this invention. The figure which shows the vicinity of the light transmission board which concerns on a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that each drawing may be drawn at a scale different from the actual scale for convenience. Moreover, in each drawing, the same reference numeral is given to the same member, and the overlapping description is omitted.

  FIG. 1 is a schematic view (ZX cross-sectional view) of main parts of an optical shaping apparatus 100 according to an embodiment of the present invention. The optical shaping apparatus 100 has a shaping unit 200 and a control unit 300 for controlling the shaping unit 200, and irradiates the liquid photocurable resin RA with modulated light to sequentially form a shaping layer, thereby forming a three-dimensional structure. Form a shaped object. The control unit 300 is connected to an image processing apparatus 400 (computer) which is an external apparatus.

  In the present embodiment, ultraviolet light (UV light) is used as modulated light, and an ultraviolet curable resin (UV curable resin) is used as the photocurable resin. However, modulated light other than UV light and a photocurable resin other than UV curable resin may be used. In addition, the shaping | molding unit 200 shown in FIG. 1 is a schematic diagram until it gets bored, and differs from an actual structure. The detailed configuration of the forming unit 200 will be described in each embodiment described later.

Example 1
Hereinafter, an optical shaping apparatus 100 according to a first embodiment of the present invention will be described. FIG. 2 is an enlarged view of the vicinity of the container 201 and the projection optical system 255 in the shaping unit 200 of the optical shaping apparatus 100 according to the present embodiment. The optical shaping apparatus 100 is the same as the optical shaping apparatus 100 shown in FIG. 1 except for the portion shown in FIG.

  The forming unit 200 according to the present embodiment includes a container 201, a holding plate 202 as a moving member, a moving mechanism 203, and a projection unit 250. The container 201 is a liquid tank for holding the liquid UV curable resin RA, and an opening is formed in the upper part thereof. The container 201 includes a container body (wall surface portion) 211 and a light transmitting plate (light transmitting portion) 212 made of a translucent material provided to close an opening formed in a lower portion (bottom surface portion) of the container body 211. And consists of.

  The UV curable resin RA has a property of curing when irradiated with UV light of a predetermined light amount or more. For this reason, it is possible to form a three-dimensional object WB having a target shape by irradiating the UV light of a predetermined light amount or more only to the area to be cured. The surface on the UV curable resin RA side of the light transmitting plate 212 is coated with a release agent for preventing the hardened modeling layer (cured portion) WA from adhering to the light transmitting plate 212. Accordingly, it is possible to prevent the holding plate 202 from being unable to move during the formation of each of the formation layers WA, and to prevent the formed formation object WB from becoming unremovable.

  The moving mechanism 203 moves the holding plate 202 in the vertical direction (± Z direction) through the opening at the top of the container 201. The moving mechanism 203 includes a pulse motor, a ball screw, and the like, and moves the holding plate 202 at an arbitrary speed or an arbitrary pitch based on a control signal from the control unit 300. In the following description, the moving direction of the holding plate 202 (vertical direction in the drawing) is Z direction, and the direction orthogonal to the Z direction (horizontal direction in the drawing) is X direction, the direction orthogonal to the Z direction and X direction ( Let the depth direction be the Y direction.

  The moving mechanism 203 moves the holding plate 202 upward (in the + Z direction) during formation of each modeling layer WA. By irradiating the UV curable resin RA with the modulated light through the light transmitting plate 212 with the holding plate 202 at the lower end position, the first shaped layer is formed in a state of being attached to the holding plate 202. Then, in a state where the first shaped layer is pulled up from the lower end position by a predetermined amount, the modulated light is irradiated to the UV curable resin RA through the light transmitting plate 212, so that the space between the first shaped layer and the light transmitting plate 212 The following shaping layer is formed. By repeating this process, the plurality of shaped layers WA can be sequentially stacked to form the shaped object WB.

  A projection unit 250 is disposed on the lower side of the container 201, that is, at a position facing the light transmitting plate 212. The projection unit 250 includes a light source 251, a beam splitter 252, an image forming element (light modulation element) 253, a drive mechanism 254, and a projection optical system 255. In FIG. 2, the optical path of the modulated light reflected (deflected) by the beam splitter 252 is unfolded and shown. Note that another optical element (a beam splitter, a mirror, or the like) for deflecting the optical path may be added to the projection unit 250 as necessary.

  The light source 251, the beam splitter 252, and the light modulation element 253 are arranged in series in the X direction. The projection optical system 255 is disposed on the upper side (+ Z side) of the beam splitter 252 so that the optical surface (final surface) on the most expansion side faces the light transmitting plate 212. The light source 251 is configured of an LED that emits UV light, a high pressure mercury lamp, and the like. The UV light emitted from the light source 251 passes through the beam splitter 252 and enters the image forming element 253. In addition, when using except UV curable resin as photocurable resin, the light source 251 may not emit UV light.

  The image forming element 253 is a light modulation element having a plurality of pixels and modulating the irradiated UV light for each pixel to generate modulated light (image light). In the present embodiment, a DMD (Digital Mirror Device) is used as the image forming element 253. As shown in FIG. 3, the image forming element 253 as a DMD is a minute device in which each of a plurality of two-dimensionally arranged pixels 261 changes (pivots) between a plurality of angular positions (on position and off position). It is composed of various mirrors. Each pixel 261 is capable of binary control to represent light and dark in the on state where the mirror is in the on position and the off state where the mirror is in the off position.

  The image processing apparatus 400 generates a plurality of image data as two-dimensional shape data of a plurality of cross sections along the Z direction from the three-dimensional shape data prepared in advance as shape data of a three-dimensional object. Each image data is “1” indicating that it is a pixel position to be modeled (modeling pixel position) with respect to a plurality of two-dimensionally arranged pixel positions, or a pixel position not to be modeled (non-modeling pixel position It is binarized data including "0" which shows that it is). The image processing apparatus 400 outputs, to the control unit 300, moving image data in which a plurality of image data are arranged in time series. Note that the image processing device 400 may be mounted inside the optical shaping device 100.

  The control unit 300 is configured as a computer including a CPU 301, a RAM 302 having a work area used for the calculation of the CPU 301, and a ROM 303. The ROM 303 is a recording medium in which the program 304 is recorded, and is a rewritable non-volatile memory such as an EEPROM. The CPU 301 executes an optical forming process of reading the program 304 recorded in the ROM 303 and controlling the forming unit 200.

  The program 304 may be recorded not in the ROM 303 but in a recording medium existing outside the control unit 300. As the recording medium, for example, a computer readable medium such as a non-volatile memory (semiconductor memory or the like), a recording disk (optical disk or magnetic disk), or a storage device (hard disk) is adopted.

  As described above, the control unit 300 sequentially performs binary control for each pixel 261 of the image forming element 253 based on each of a plurality of image data in moving image data output from the image processing apparatus 400. The UV light is modulated for each pixel 261. The control unit 300 can also express a halftone by duty control that switches the on state and the off state of each pixel 261 at high speed.

  In the present embodiment, although the case of using a DMD as the image forming element 253 has been described, a reflective liquid crystal panel or a transmissive liquid crystal panel may be used as the image forming element 253. Also in this case, not only light and dark representation by binary control of the reflectance or transmittance of a pixel, but also halftone representation by high-speed switching of reflectance or transmittance are possible. Not limited to these elements, other elements may be used as the image forming element 253 as long as they are elements capable of forming modulated light having light and shade and half tone.

  The beam splitter 252 transmits UV light from the light source 251 as described above, and reflects modulated light from the image forming element 253 toward the projection optical system 255. The projection optical system 255 is configured of one or more optical elements (lenses), and projects (irradiates) the modulated light from the beam splitter 252 onto the UV curable resin RA. At this time, the modulated light is condensed at a position optically conjugate with the image forming element 253 in the container 201 to form an image of each pixel of the image forming element 253.

  In the present embodiment, the condensing position (imaging position) of this modulated light is taken as the modeling position. The shaping position in the present embodiment is a position immediately above the above-described light transmitting plate 212 in the container 201, and the UV curable resin RA at this position receives the modulated light, whereby the shaping layer WA is formed. By making the aperture stop in the projection optical system 255 the most narrowed, it is possible to condense the modulated light from each pixel of the image forming element 253 at the modeling position with high accuracy, and the modeling layer WA of good resolution is obtained. It can be formed.

  The control unit 300 controls not only the control of the image forming element 253 described above, but also the control of the light source 251, the moving mechanism 203, and the driving mechanism 254. At this time, the control unit 300 causes the moving mechanism 203 to pull up the holding plate 202 continuously or intermittently at a speed synchronized with the formation (curing) of the modeling layer WA according to the moving image data described above. As a result, it is possible to form the three-dimensional object WB such that new ones of the first three-dimensional layers WA are sequentially stacked on the first three-dimensional layer WA whose upper end is held by the holding plate 202.

  As described above, in the optical shaping apparatus 100 according to the present embodiment, when forming each of the plurality of modeling layers WA sequentially stacked, the projection unit 250 collectively projects the modulated light to a wide area of the modeling position. Thereby, UV curable resin RA which exists in a wide range can be hardened at once. Therefore, the time (modeling time) required for modeling of modeling thing WA can be shortened compared with the device which hardens one modeling layer one by one sequentially by scanning a modeling position with a laser beam etc. optically.

  Here, as described above, in the configuration in which only one image forming element and one projection optical system are provided, if it is intended to simultaneously irradiate light to a wide area of the photocurable resin, an off-axis light beam to the light transmission plate The incident angle of However, the term “off-axis light ray” as used herein refers to a light ray that is far from the optical axis of the projection optical system among the light rays that reach the modeling position. When the incident angle of the off-axis light beam to the light transmission plate becomes large, the position of the end of the shaping layer formed by the off-axis light beam deviates from the design value, which makes it difficult to obtain good modeling accuracy. . This will be described in detail below.

  FIG. 8 is a schematic view of the vicinity of the light transmitting plate 812 in the optical shaping apparatus according to the conventional example. Here, in order to make the description easy to understand, the angle of each light beam, the curing area PA, and the like are made different from the actual dimensions. However, the cured area PA here is an area which receives light of a predetermined light amount or more in the UV curable resin RA (is set to a predetermined light density or more) to be cured. By simultaneously curing the plurality of curing regions PA, the shaped layer WA is formed. As shown in FIG. 8, in the light transmitting plate 812 according to the conventional example, both an incident surface on which light from the projection optical system is incident and an exit surface from which light from the incident surface is emitted are flat.

  At this time, since an on-axis light beam reaching the optical axis of the projection optical system at the modeling position is incident from a direction perpendicular to the light incident surface of the light transmitting plate 812, the hardened area PA is formed at a desired position. . On the other hand, an off-axis ray reaching an area away from the optical axis of the projection optical system at the modeling position obliquely enters the light incident surface of the light transmission plate 812 at a large incident angle. The outgoing angle also increases. Therefore, as shown in FIG. 8, the cured area PA corresponding to the off-axis ray is largely inclined with respect to the optical axis direction (Z direction).

  For example, when the height of one modeling layer in the optical axis direction is 200 μm and the exit angle of the off-axis ray with respect to the exit surface is 20 degrees, the positions in the X direction of the upper and lower portions of the curing region PA corresponding to the off-axis ray are The relative shift of 200 μm × tan (20 °) = 73 μm occurs. It is difficult to realize good modeling accuracy when such modeling positional deviation occurs. In particular, when attempting to widen the projection range while reducing the outer diameter and the total length of the projection optical system in order to miniaturize the optical shaping apparatus, this problem becomes remarkable.

  Therefore, in the optical shaping apparatus 100 according to the present embodiment, by making the light transmitting plate 212 have a positive refractive power (power), the incident angle of the off-axis light beam to the photocurable resin is reduced, and a good shaping accuracy is obtained. Is realized. The effect by the light transmission board 212 which concerns on a present Example is demonstrated using a comparative example. FIG. 4 shows the appearance of light rays in the vicinity of the light transmitting plate in the optical shaping apparatus, and FIG. 4 (a) shows the optical shaping apparatus 100 according to the present embodiment, and FIG. 4 (b) shows a comparison. Fig. 2 shows an optical shaping apparatus according to an example. In addition, about the optical shaping | molding apparatus which concerns on a comparative example, structures other than the light transmission board 512 shall be the same as that of a present Example.

  As shown in FIG. 4 (b), in the optical shaping apparatus according to the comparative example, since both the incident surface and the exit surface of the light transmitting plate 512 are flat, they are as good as the conventional example shown in FIG. I can not get modeling accuracy. On the other hand, as shown in FIG. 4A, in the optical shaping apparatus 100 according to the present embodiment, the incident surface of the light transmitting plate 212 is convex toward the projection optical system 255, and the output surface of the light transmitting plate 212 is flat. By doing this, the light transmitting plate 212 is given positive refractive power. As a result, for an off-axis ray incident at a large incident angle with respect to the incident surface of the light transmitting plate 212, the emission angle when emitted from the output surface toward the UV curable resin RA can be reduced. It is possible to suppress the decrease in accuracy.

  The light transmitting plate 212 according to the present embodiment plays a role as an optical element for transmitting the light from the projection optical system 255 and a role as a container for holding the UV curable resin RA. That is, in the light transmitting plate 212, the incident surface is in contact with air, and the emission surface is in contact with the UV curable resin RA. At this time, since the refractive index of the UV curable resin RA is larger than the refractive index of air, it is difficult to obtain sufficient refractive power even if the exit surface of the light transmitting plate 212 has a curvature. In addition, since the exit surface of the light transmitting plate 212 is disposed closer to the modeling position than the entrance surface, the shape of the exit surface has a great influence on the modeling accuracy.

  Therefore, in the present embodiment, the shape of the light emitting surface of the light transmitting plate 212 is a flat surface for which high processing accuracy can be easily obtained, and the light incident surface of the light transmitting plate 212 in contact with air is a curved surface. However, the plane herein is not limited to a strict plane, but includes a substantially plane having a radius of curvature of 1000 mm or more. As a result, it is possible to make the light transmitting plate 212 into a shape that is easy to process, and to obtain sufficient refractive power without giving each surface a large curvature.

  In the present embodiment, the incident surface of the light transmitting plate 212 is formed to be a spherical shape which is easy to process, but by making the incident surface to be an aspheric surface if necessary, the aberration generated in the projection optical system 255 is better. Correction may be made. Alternatively, the incident surface of the light transmitting plate 212 may be a Fresnel lens. In addition, the light-transmitting plate 212 may have a positive refracting power by forming the light-emitting plate as a curved surface and making the light-transmitting plate 212 into a meniscus shape or a biconvex shape as necessary. That is, as long as positive refracting power can be given by forming at least one of the incident surface and the exit surface as a curved surface, the light transmitting plate 212 may have any shape.

  Further, in the present embodiment, the container main body 211 forming part of the side surface portion and the bottom surface portion (wall surface portion) of the container 201 and the light transmitting plate 212 disposed on the bottom surface portion of the container 201 are different members ( The container 201 is obtained by preparing them separately and bonding them together. As described above, by using the container body 211 and the light transmitting plate 212 as separate members, a general processing method such as cutting or polishing is adopted when giving the light transmitting plate 212 a positive refracting power. Manufacturing the light transmission plate 212 is easy. However, bonding here includes bonding with an adhesive, welding, fitting and the like.

Here, the incident angle of the outermost off-axis ray with respect to the incident surface of the light transmitting plate 212 is θ1, and the outgoing angle of the outermost off-axis light with respect to the emitting surface of the light transmitting plate 212 is θ2. However, the most off-axis ray here indicates a ray which is the farthest from the optical axis of the projection optical system 255 among the rays reaching the shaping position. Further, the incident angle indicates the angle formed by the light beam when entering the incident surface of the light transmitting plate 212 and the optical axis, and the emission angle indicates the light beam and light when exiting from the light exiting surface of the light transmitting plate 212 Indicates the angle with the axis. The signs of the incident angle θ1 and the outgoing angle θ2 define the direction in which the light beam moves away from the optical axis as positive and the direction in which the light beam approaches as negative. At this time, it is desirable to satisfy the following conditional expression (1).
0.0 ≦ θ2 / θ1 ≦ 0.50 (1)

  When the value exceeds the upper limit of the conditional expression (1), the emission angle θ2 becomes too large with respect to the incident angle θ1, and the angle correction of the outermost off-axis light by the light transmission plate 212 becomes insufficient. It will be difficult to get On the other hand, if the lower limit of the conditional expression (1) is exceeded, the sign of the output angle θ2 is reversed with respect to the incident angle θ1, and the most off-axis ray emitted from the output surface tends toward the optical axis. The light transmission plate 212 overcorrects the angle of the outermost off-axis ray. Therefore, the amount of change (sensitivity) of the optical performance with respect to the eccentricity of the light transmitting plate 212 and the shape error becomes high, and an aberration occurs, so that it is difficult to obtain a good modeling accuracy.

The incident angle θ1 is 11 degrees in any of the optical shaping apparatus 100 according to the present embodiment shown in FIG. 4 (a) and the optical shaping apparatus according to the comparative example shown in FIG. 4 (b). However, in the comparative example, since the emission angle θ2 is 7.2 deg and θ2 / θ1 = 0.67, the above conditional expression (1) is not satisfied, and good modeling accuracy can not be obtained. On the other hand, in the present embodiment, since the emission angle θ2 is 1.4 deg and θ2 / θ1 = 0.13, the conditional expression (1) is satisfied, and a good modeling accuracy is obtained. Furthermore, it is more preferable to satisfy the following conditional expression (1a).
0.0 ≦ θ2 / θ1 ≦ 0.30 (1a)

In addition, it is desirable to design the projection optical system 255 and the light transmitting plate 212 so that the above-described emission angle θ2 (deg) satisfies the following conditional expression (2).
0.0 ≦ θ2 ≦ 5.0 (2)

By satisfying conditional expression (2), the emission angle θ2 becomes 5.0 deg or less, and tan (5.0 °) = 0.087, so the positions in the X direction of the upper and lower portions of the cured region PA described above The amount of displacement can be suppressed to 10% or less of the height of the shaping layer WA. If the upper limit of the conditional expression (2) is exceeded, the positional deviation between the upper and lower portions of the cured area PA becomes large, and it becomes difficult to obtain a good modeling accuracy. On the other hand, if the lower limit of the conditional expression (2) is exceeded, the emission angle θ2 becomes a negative value, and it becomes difficult to obtain good modeling accuracy as in the case of being lower than the lower limit of the conditional expression (1). Furthermore, it is more preferable to satisfy the following conditional expression (2a).
0.0 ≦ θ2 ≦ 4.5 (2a)

Further, when the width of the irradiation area (full irradiation area width) on the exit surface of the light transmission plate 212 is W, and the focal length of the optical system (entire system) including the projection optical system 252 and the light transmission plate 212 is f, It is desirable to satisfy the following conditional expression (3). Here, the irradiation area indicates the width of the passage area of the light flux from the projection optical system 255 on the exit surface of the light transmitting plate 212 (the distance between the outermost off-axis rays).
0.50 ≦ W / f ≦ 5.0 (3)

As the upper limit of conditional expression (3) is exceeded, the focal length of the entire system becomes too short, and it is necessary to increase the incident angle θ1 in order to secure a sufficiently wide irradiation area, as described above It becomes easy to cause the formation position deviation. If the lower limit of conditional expression (3) is not reached, on the other hand, the focal length of the entire system becomes too long, which makes it difficult to miniaturize the entire apparatus. Furthermore, it is more preferable to satisfy the following conditional expression (3a).
0.80 ≦ W / f ≦ 3.5 (3a)

Further, when the distance between the light transmitting plate 212 and the projection optical system 255 is T1 and the distance from the image forming element 253 to the light emitting surface of the light transmitting plate 212 is L on the optical axis of the projection optical system 255, the following It is desirable to satisfy conditional expression (4). However, the distance between the light transmitting plate 212 and the projection optical system 255 indicates the distance from the incident surface of the light transmitting plate 212 to the final surface of the projection optical system 255. Further, the distance L corresponds to the total length (length of the entire system) of the optical system configured by the projection optical system 252 and the light transmitting plate 212.
0.30 ≦ T1 / L ≦ 0.80 (4)

If the upper limit of the conditional expression (4) is exceeded, the distance between the light transmitting plate 212 and the projection optical system 255 becomes too large, and the amount of change in optical performance relative to each relative displacement in the direction perpendicular to the optical axis The (relative eccentricity sensitivity) becomes high. Therefore, when positional deviation of each member occurs due to a manufacturing error or the like, it becomes difficult to obtain a good modeling accuracy. On the other hand, if the lower limit of conditional expression (4) is not reached, the distance between the light transmitting plate 212 and the projection optical system 255 becomes too small, and the outer diameter of the projection optical system 255 is sufficient to secure a sufficiently wide illumination area. In addition, it is necessary to increase the overall length, making it difficult to miniaturize the entire apparatus. Furthermore, it is more preferable to satisfy the following conditional expression (4a).
0.40 ≦ T1 / L ≦ 0.65 (4a)

Further, when the lateral magnification of the entire system is β, it is desirable to satisfy the following conditional expression (5). However, the lateral magnification of the entire system here is the ratio of the angle of view (image height) at the exit surface of the light transmitting plate 212 to the angle of view (object height) at the surface of the image forming element 253 which is the object surface. Is the value of Here, the exit surface of the light transmitting plate 212 is considered to be an image surface (modeling position).
−20 ≦ β ≦ −2.0 (5)

If the upper limit of conditional expression (5) is exceeded, the lateral magnification of the entire system becomes too small, and the final surface of projection optical system 255 approaches light transmitting plate 212, and the outer diameter and total length of projection optical system 255 become large. It becomes difficult to miniaturize the entire device. On the other hand, when the value goes below the lower limit of the conditional expression (5), the incident angle θ1 becomes too large, and it becomes difficult to reduce the emission angle θ2 by the light transmitting plate 212. In this case, in order to sufficiently reduce the emission angle θ2, it is necessary to significantly increase the curvature of the light incident surface of the light transmission plate 212, and the change in optical performance due to the eccentricity of the light transmission plate 212 becomes large. It becomes difficult to obtain good modeling accuracy. Furthermore, it is more preferable to satisfy the following conditional expression (5a).
−10 ≦ β ≦ −2.5 (5a)

Moreover, when the curvature radius of the entrance plane of the light transmitting plate 212 is R [mm], it is desirable to satisfy the following conditional expression (6).
30 ≦ R ≦ 200 (6)

If the upper limit of the conditional expression (6) is exceeded, the refractive power of the incident surface of the light transmitting plate 212 becomes too small, and it becomes difficult to reduce the emission angle θ2 by the light transmitting plate 212. On the other hand, when the value goes below the lower limit of the conditional expression (6), the refractive power of the incident surface of the light transmitting plate 212 becomes too large, and it becomes difficult to correct the aberration generated in the entire system. Furthermore, it is more preferable to satisfy the following conditional expression (6a).
50 ≦ R ≦ 180 (6a)

  Table 1 shows specification values of the optical shaping device 100 according to the present example. As shown in Table 1, the optical shaping apparatus 100 according to this example satisfies the conditional expressions (1) to (5) described above.

  Table 2 shows lens data of the optical system according to the present example. In Table 2, the radius of curvature of each optical surface from the image forming element 253 which is the object surface to the exit surface of the light transmitting plate 212 which is the image surface, the surface distance on the optical axis between the optical surfaces, the medium between the optical surfaces The index of refraction for the d line of and the radius (effective radius) of the effective diameter of each optical surface are shown. As shown in Table 2, the optical shaping device 100 according to the present example satisfies the conditional expression (6) described above.

  As mentioned above, according to the optical shaping apparatus 100 which concerns on a present Example, favorable modeling precision is realizable by simple structure.

Example 2
Hereinafter, an optical shaping apparatus 100 according to a second embodiment of the present invention will be described. In the optical shaping apparatus 100 according to the present embodiment, the description of the same configuration as that of the optical shaping apparatus 100 according to the first embodiment described above will be omitted.

  FIG. 5 is an enlarged view of the vicinity of the container 261 and the projection optical system 265 in the optical shaping apparatus 100 according to the present embodiment. In the optical shaping apparatus 100 according to the present embodiment, compared with the optical shaping apparatus 100 according to the first embodiment, in order to suppress the increase in the outer diameter and the total length of the projection optical system 255 while setting the width of the irradiation area wider. The incident angle to the light transmission plate 222 is made larger.

  FIG. 6 shows the appearance of light rays in the vicinity of the light transmitting plate in the optical shaping apparatus, and FIG. 6 (a) shows the optical shaping apparatus 100 according to the present embodiment, and FIG. 6 (b) shows a comparison. Fig. 2 shows an optical shaping apparatus according to an example. In addition, about the optical shaping | molding apparatus which concerns on a comparative example, structures other than the light transmission board 522 shall be the same as that of a present Example. As apparent from FIG. 6, even when the incident angle θ1 is larger than that of the first embodiment, the emission angle θ2 can be sufficiently reduced by providing the light transmitting plate 222 with a positive refractive power.

  Table 3 shows the specification values of the optical forming device 100 according to the present example. As shown in Table 3, the optical shaping device 100 according to the present example satisfies the conditional expressions (1) to (5) described above.

  Table 4 shows lens data of the optical system according to the present example. As shown in Table 4, the optical shaping apparatus 100 according to this example satisfies the conditional expression (6) described above.

[Modification]
Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the present invention.

  In the optical shaping apparatus 100 according to the above-described embodiment, the light transmitting plate 212 is provided on the bottom of the container 201, but the present invention is not limited to this configuration. For example, as shown in FIG. 7A, a configuration in which the light transmitting plate 212 is provided on the upper part of the container 201, or a configuration in which the light transmitting plate 212 is provided on the side surface of the container 201 as shown in FIG. It may be adopted. 7A, the holding plate 202 is moved in the -Z direction, and in the structure shown in FIG. 7B, the shaped layer WA is sequentially formed by moving the holding plate 202 in the -X direction. can do. Even in such a configuration, the effect of the present invention can be obtained by giving the light transmitting plate 212 a positive refractive power.

  Moreover, in the optical shaping apparatus 100 which concerns on embodiment mentioned above, although the sequential formation of the modeling layer WA is enabled by coating a mold release agent on the light transmission board 212, it is not restricted to this structure. For example, by forming the light transmitting plate 212 with a material that transmits oxygen, such as Teflon (registered trademark), a dead zone (dead zone) that does not cure even in the vicinity of the light transmitting plate 212 in the UV curable resin RA ) May be formed. Further, the modeling layer WA may not be fixed to the light transmitting plate 212 by finely vibrating the container 201. Alternatively, each time the shaped object WA adheres to the light transmitting plate 212, the holding plate 202 may be pulled upward to peel off the forming layer WA fixed to the light transmitting plate 212.

  For example, instead of the image forming element 253, a deflector may be employed, and light from a light source may be deflected by the deflector to scan a modeling position to form a shaped object. In this configuration, for example, a laser light source can be adopted as a light source, and a galvano mirror can be adopted as a deflector. In this case, the projection optical system 255 irradiates the scanning light from the deflecting unit to the shaping position through the light transmitting plate 212, and the control unit 300 controls the deflecting unit based on each of the plurality of two-dimensional shape data. In addition, as necessary, a configuration including both the image forming element 253 and the deflector may be employed.

  Alternatively, the container 201 may be removable (replaceable) from the modeling unit 200. For example, by preparing a plurality of containers 201 holding photocurable resins different in color and property from one another and attaching and detaching them to the modeling unit 200, it is possible to form a multicolor shaped object or a more complex shaped object. it can. However, when this configuration is adopted, it is desirable to provide a mechanism for adjusting the position of the container 201 because it is necessary to adjust the position (eccentricity adjustment) of the light transmitting plate 212 when the container 201 is attached.

  Alternatively, as necessary, a configuration in which the container 201 having the light transmitting plate 212 having positive refractive power and the container having the light transmitting plate having no refractive power may be exchanged. In this case, it is desirable to provide a mechanism for adjusting the position of the container 201 and the position of the lens constituting the projection optical system 255 in order to correct the change in the optical performance due to the replacement of the container.

  In addition, the light transmitting plate 212 may be configured by a plurality of optical members as needed. For example, by forming the light transmitting plate 212 by bonding an optical member having a positive power and an optical member having a negative power to each other, correction of chromatic aberration can be performed by the light transmitting plate 212. Good.

100 stereolithography apparatus 201 container 202 holding plate (moving member)
212 Translucent board (translucent part)
251 light source 253 image forming element (light modulation element)
255 Projection optical system 300 Control unit RA UV curable resin (photo curable resin)
WA modeling layer (hardened part)

Claims (12)

A container having a light transmitting portion and holding a liquid photocurable resin;
A projection optical system that irradiates light to the photocurable resin through the light transmitting section;
A control unit that controls the irradiation of the light based on each of a plurality of two-dimensional shape data obtained from three-dimensional shape data;
And a moving member configured to move a cured portion of the photocurable resin that has received and cured the light in a direction away from the light transmitting portion.
The optical shaping apparatus characterized in that the light transmitting part has positive refractive power. Assuming that the incident angle of the most off-axial ray with respect to the incident surface of the light transmitting portion is θ1, and the outgoing angle of the most off-axial light with respect to the emitting surface of the light transmitting portion is θ2.
0.0 ≦ θ2 / θ1 ≦ 0.50
The optical shaping apparatus according to claim 1, wherein the conditional expression is satisfied. Assuming that the emission angle of the most off-axis ray with respect to the emission surface of the light transmitting portion is θ2 (deg)
0.0 ≦ θ2 ≦ 5.0
The optical shaping apparatus according to claim 1 or 2, wherein the conditional expression is satisfied.   The optical shaping apparatus according to any one of claims 1 to 3, wherein an incident surface of the light transmitting portion is a convex surface toward the projection optical system.   The optical shaping apparatus according to any one of claims 1 to 4, wherein an exit surface of the light transmitting portion is a flat surface.   The optical shaping apparatus according to any one of claims 1 to 5, wherein the container has a wall surface portion joined to the light transmitting portion. Assuming that the width of the irradiation area on the exit surface of the light transmitting portion is W, and the focal length of the optical system including the projection optical system and the light transmitting portion is f,
0.50 ≦ W / f ≦ 5.0
The optical shaping apparatus according to any one of claims 1 to 6, wherein the conditional expression is satisfied. When an interval between the light transmitting portion and the projection optical system is T1 and an overall length of the optical system including the projection optical system and the light transmitting portion is L on the optical axis of the projection optical system,
0.30 ≦ T1 / L ≦ 0.80
The optical shaping device according to any one of claims 1 to 7, wherein the conditional expression is satisfied. Assuming that the lateral magnification of the optical system including the projection optical system and the light transmitting portion is β,
−20 ≦ β ≦ −2.0
The optical shaping apparatus according to any one of claims 1 to 8, wherein the conditional expression is satisfied. When the radius of curvature of the incident surface of the light transmitting portion is R [mm],
30 ≦ R ≦ 200
The optical shaping apparatus according to any one of claims 1 to 9, wherein the conditional expression is satisfied. And a light modulation element having a plurality of pixels and modulating light from a light source for each of the pixels,
The projection optical system irradiates the photocurable resin with the modulated light from the light modulation element through the light transmitting section.
The optical shaping apparatus according to any one of claims 1 to 10, wherein the control unit controls the light modulation element based on each of the plurality of two-dimensional shape data. A deflection unit configured to deflect light from a light source to scan the photocurable resin;
The projection optical system irradiates the light curable resin with the scanning light from the deflection unit via the light transmission unit.
The optical shaping apparatus according to any one of claims 1 to 10, wherein the control unit controls the deflection unit based on each of the plurality of two-dimensional shape data.

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