Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/10—Processes of additive manufacturing
  • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
  • B29C64/124—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified
  • B29C64/129—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified characterised by the energy source therefor, e.g. by global irradiation combined with a mask
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
  • B29C64/264—Arrangements for irradiation
  • B29C64/277—Arrangements for irradiation using multiple radiation means, e.g. micromirrors or multiple light-emitting diodes [LED]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor

Definitions

• the present disclosure relates to a stereolithographic device, a reduction projection optical component for the stereolithographic device, and a method for manufacturing a stereolithographic object.
• a stereolithography apparatus such as International Publication No. 2018/154847 has been known as an apparatus for modeling a three-dimensional structure having a three-dimensional shape.
• the stereolithography device disclosed in International Publication No. 2018/154847 includes a light source device and an optical element that collects light emitted from the light source device. Further, a container in which a liquid photocurable resin that reacts with ultraviolet rays is stored is provided as a liquid tank.
• a light source device includes a plurality of light emitting elements that emit ultraviolet rays and a partition wall that serves as a partition wall that partitions adjacent light emitting elements.
• One pixel is formed by the partition wall and the light emitting element housed within the area surrounded by the partition wall.
• an optical element forms a spot light that is irradiated onto a photocurable resin by condensing ultraviolet rays emitted from one pixel.
• the spot light is irradiated onto the liquid surface from above the liquid tank along a direction perpendicular to the liquid surface of the liquid tank. Note that in this specification, the direction perpendicular to the liquid surface is also simply referred to as the "irradiation direction.”
• An exposure image designed with a desired two-dimensional pattern is formed in the formation region within the liquid tank by irradiation with a plurality of spot lights. Irradiation with ultraviolet rays causes a photocuring reaction in the photocurable resin in the formation area where the exposed image is formed. As a result, a cured resin layer having a two-dimensional pattern similar to the exposed image is formed in the formation region with a predetermined thickness.
• the stereolithography apparatus of International Publication No. 2018/154847 is provided with a stage that supports the formed resin cured layer from below.
• the stage sinks into the liquid tank while supporting the cured resin layer, and the liquid photocurable resin above the cured resin layer is irradiated with ultraviolet rays.
• ultraviolet rays By repeating the subsidence of the stage and the irradiation of ultraviolet rays, a plurality of cured resin layers are stacked vertically, and as a result, a three-dimensional object having a desired three-dimensional shape can be finally obtained.
• Patent Document 1 International Publication No. 2018/154847
• light energy density means light energy per unit area.
• the present disclosure has been made focusing on the above, and can improve the efficiency of light use.
• Means for solving the above problems include the following aspects.
• a plurality of pixels each including a liquid tank in which a liquid photocurable resin is accumulated, a partition wall, and a light-emitting element housed in the partition wall are arranged in a periodic matrix.
• a light source device with a maximum width of 200 ⁇ m or less is placed between the light source device and the liquid tank, and the light emitted from one pixel is used to form a spot light that is irradiated onto the photocurable resin, and multiple spots are formed.
• a stereolithography apparatus that includes an optical element that forms an exposure image in a formation area in a liquid tank using light, and a stage that supports a resin cured layer of a photocurable resin that is cured by the exposure image and moves in the vertical direction.
• the optical element has a microlens that condenses light emitted from one pixel, and the pitch of the microlens is greater than or equal to the light source wavelength [nm] of the light emitting element and less than or equal to the pitch of one pixel. 1>.
• optical element according to ⁇ 1> or ⁇ 2> above wherein the optical element has a microlens that condenses light emitted from one pixel, and a plurality of microlenses are arranged for one pixel. Modeling equipment.
• ⁇ 4> The stereolithography device according to ⁇ 2> or ⁇ 3> above, wherein the microlenses are circular in plan view, and the pitch of the microlenses is at least twice the light source wavelength [nm] of the light emitting element. .
• the optical element described in ⁇ 1> above has a plurality of slits that narrow down the light emitted from one pixel, and is an aperture that uses the slits to form a spot light that is irradiated onto the photocurable resin. stereolithography device.
• the light source device is disposed below the liquid tank, the cured resin layer is supported on the lower side of the stage, and the stage is capable of rising while supporting the cured resin layer.
• the stereolithography device according to any one of ⁇ 5>.
• ⁇ 7> The stereolithography apparatus according to any one of ⁇ 1> to ⁇ 6> above, wherein a switching element corresponding to each of the plurality of light emitting elements is provided.
• ⁇ 8> It has a liquid tank in which liquid photocurable resin is accumulated and a projection surface formed by a plurality of single pixels, and has an area N times (however, N>1) the area of the stereolithographic object to be modeled.
• a light source device that projects a printing image from a projection surface, and a light source device that is placed between the projection surface of the light source device and the bottom of the liquid tank and reduces the area of the printing image to 1/M (however, M>1)
• a light having a reduction projection optical component that projects onto a modeling surface in a bath, and a stage that supports a resin cured layer of a photocurable resin cured by a modeling image on the modeling surface and moves in the vertical direction.
• Modeling equipment Modeling equipment.
• the reduction projection optical component includes a first light focusing member disposed on the side of the light source device, and an optical axis correction device that corrects the optical axis of the light focused by the first light focusing member in a direction perpendicular to the modeling surface.
• the light source device is disposed below the liquid tank, the cured resin layer is supported on the lower side of the stage, and the stage is capable of rising while supporting the cured resin layer, ⁇ 8> ⁇
• the stereolithography device according to any one of ⁇ 11>.
• ⁇ 13> Projecting a printing image of N times the area of the stereofabricated object to be formed (where N>1) from a projection plane formed by a plurality of one pixel of the light source device, and reducing projection optical components.
• the area of the printing image is reduced to 1/M (however, M>1) using the method, and the printing image with the reduced area is projected onto the printing surface in a liquid tank in which liquid photocurable resin is accumulated. a step of curing a photocurable resin.
• ⁇ 14> It has a liquid tank in which a liquid photocurable resin is accumulated and a projection surface formed by a plurality of single pixels, and has an area N times (however, N>1) the area of the stereolithographic object to be modeled.
• Reduction projection optics used in a stereolithography apparatus which includes a light source device that projects a modeling image from a projection surface, and a stage that supports a resin cured layer of photocurable resin cured by the modeling image and moves in the vertical direction.
• a reduction projection optical component for stereolithography equipment which includes a light source device that projects a modeling image from a projection surface, and a stage that supports a resin cured layer of photocurable resin cured by the modeling image and moves in the vertical direction.
• FIG. 2 is a front view illustrating the stereolithography apparatus according to the first embodiment, with part of the liquid tank and the light irradiation device cut away.
• FIG. 4 is a sectional view taken along line 2-2 in FIG. 3, illustrating a light source device and an optical element of the light irradiation device according to the first embodiment.
• FIG. 2 is a plan view illustrating a light source device and an optical element of the light irradiation device according to the first embodiment.
• FIG. 3 is a diagram illustrating the operation of an optical element when the optical element provided in a unit area corresponding to one pixel is one microlens.
• FIG. 1 is a front view illustrating the stereolithography apparatus according to the first embodiment, with part of the liquid tank and the light irradiation device cut away.
• FIG. 4 is a sectional view taken along line 2-2 in FIG. 3, illustrating a light source device and an optical element of the light irradiation device according to the first embodiment.
• FIG. 2 is
• FIG. 7 is a diagram illustrating the operation of an optical element when the optical element provided in a unit area corresponding to one pixel is a plurality of microlenses. It is a top view explaining the switching element of the light irradiation device concerning a 1st embodiment.
• FIG. 2 is a diagram illustrating a method for manufacturing a stereolithographic object using the stereolithography apparatus according to the first embodiment, with a part of the liquid tank and a light irradiation device cut away. It is a top view explaining the light source device and optical element of the light irradiation device concerning a 1st modification.
• FIG. 7 is a plan view illustrating a light source device and an optical element of a light irradiation device according to a second modification.
• FIG. 10 is a sectional view taken along line 10-10 in FIG. 9, illustrating a light source device and an optical element of a light irradiation device according to a third modification.
• FIG. 7 is a plan view illustrating a light source device and an optical element of a light irradiation device according to a second embodiment.
• 13 is a sectional view taken along line 13-13 in FIG. 12, illustrating a light source device and an optical element of a light irradiation device according to a second embodiment.
• FIG. 7 is a front view illustrating a stereolithography apparatus according to a third embodiment with a part of a liquid tank and a light irradiation device cut away. It is a perspective view explaining the optical element of the light irradiation device concerning a 3rd embodiment.
• FIG. 7 is a diagram illustrating a method of manufacturing a stereolithographic object using a stereolithography apparatus according to a third embodiment, with a part of a liquid tank and a light irradiation device cut away.
• Image data for stereolithographic modeling of the first resin cured layer, a modeling image having an area N times the area of the stereolithographic object in the light source device in the case of M N, and an area of 1/M in the optical element.
• FIG. 2 is a perspective view illustrating a state in which a first resin cured layer and a second resin cured layer are laminated in stereolithography.
• FIG. 7 is a diagram illustrating a stereolithography apparatus according to a fifth modification with a part of a liquid tank and a light irradiation device cut away.
• the stereolithography apparatus 10 includes a liquid tank 12, a stage 14, a hanging member 16 for suspending the stage 14, and a light irradiation device 20.
• the liquid tank 12 has a bottom and side walls, and is entirely made of a translucent material.
• a liquid photocurable resin 18 is accumulated in the liquid tank 12 . Note that in the present disclosure, it is not essential that the entire liquid tank has translucency. In the present disclosure, it is sufficient that at least a portion of the bottom or side wall through which the light irradiated by the light irradiation device passes has translucency.
• stage 14 supports the resin cured layer of the photocurable resin 18 that has been cured by the exposed image, and moves in the vertical direction in FIG. 1 . That is, the stage 14 can be raised and lowered while supporting the cured resin layer. Further, in the first embodiment, the cured resin layer is supported on the lower surface side of the stage 14 via support pins 32. That is, in the first embodiment, the stereolithography apparatus 10 is a hanging 3D printer.
• the light irradiation device 20 is provided below the liquid tank 12 in FIG. 1, and irradiates light onto the lower surface of the stage 14 through the bottom of the liquid tank 12, which has translucency.
• the first embodiment exemplifies the case of stereolithography using a DLP (Digital Light Processing) method, which is a surface exposure method
• the stereolithography of the present disclosure is not limited to the DLP method, and may be performed using a surface exposure method. Good to have.
• the light irradiation device 20 includes a casing 22, a light source device 24 provided inside the casing 22, and an optical element 26 arranged between the light source device 24 and the liquid tank 12 inside the casing 22. Be prepared.
• image data for modeling is input to the light irradiation device 20.
• the modeling image data is created using, for example, CAD software or CAM software.
• the light irradiation device 20 emits light of a predetermined wavelength necessary for stereolithography, such as ultraviolet light, toward the lower side of the stage 14 immersed in the liquid tank 12 based on the input image data for modeling. Selectively irradiate.
• the light source device 24 includes a substrate 24A, a partition wall 24B, a light emitting element 24C, a sealing material 24D, and a protective layer 24E.
• the light source device 24 collectively emits light from a plurality of pixels 23 to the formation area 18A of the photocurable resin 18. Note that in FIG. 2, for convenience of explanation, illustration of the casing 22 illustrated in FIG. 1 is omitted.
• the substrate 24A is, for example, a glass substrate or a resin substrate.
• the substrate 24A is provided with various circuits for driving the light emitting elements 24C, switching elements such as TFTs (Thin Film Transistors), and various wirings such as scanning lines, signal lines, and power lines. Illustrations of various circuits are omitted. Further, as will be explained later, FIG. 5 illustrates the switching element 36, the X electrode members X1 and X2, and the Y electrode members Y1 and Y2.
• the partition wall 24B is formed of, for example, a resin material or a metal material. As shown in FIG. 3, a plurality of partition walls 24B are provided along each of the X direction and the Y direction. The X direction and the Y direction are orthogonal to each other. Therefore, in plan view, the partition walls 24B in the X direction and the partition walls 24B in the Y direction appear in a lattice shape.
• One light emitting element 24C is provided in the space inside the grid surrounded by the partition wall 24B.
• a plurality of light emitting elements 24C are arranged in a periodic matrix in a plan view.
• the light emitting element 24C is, for example, a micro light emitting diode (micro LED).
• the light emitting element 24C is housed in the partition wall 24B and the partition wall 24B.
• the light emitting element 24C emits ultraviolet light having a wavelength of around 400 nm. Note that in the present disclosure, the light emitting element is not limited to micro LEDs, and any element that emits light with a wavelength that can cure the photocurable resin 18, such as an organic LED, can be used as appropriate.
• the micro LED used as a light emitting element in the present disclosure is not electrically controlled.
• the micro LED is itself a light source that emits exposure light, and the light emitted by the micro LED is used as it is as exposure light.
• the amount of light passing through the liquid crystal is electrically controlled by a voltage applied to the liquid crystal. That is, the usage and usage conditions of light in the light emitting element of the present disclosure are different from the usage and usage status of light in the micro LED of a liquid crystal display.
• a plurality of light emitting elements 24C arranged in a matrix are arranged to face the photocurable resin 18 in the liquid tank 12.
• FIG. 3 shows an example in which four light emitting elements are arranged in the X direction and two light emitting elements are arranged in the Y direction in a matrix, in the present disclosure, the number of light emitting elements and the arrangement pattern can be set arbitrarily.
• the sealing material 24D can be made of, for example, a resin having a translucent property that allows light to pass through, such as epoxy resin or silicone resin. As shown in FIG. 2, the sealing material 24D seals the light emitting element 24C inside the partition wall 24B.
• a protective layer 24E is provided on the partition wall 24B in FIG.
• the protective layer 24E protects the light emitting element 24C.
• the protective layer 24E can be made of, for example, a transparent resin film that allows light to pass therethrough.
• one pixel 23 in the first embodiment includes a light emitting element 24C inside and is constituted by an area surrounded on all sides by partition walls 24B. Therefore, like the light emitting element 24C, a plurality of pixels 23 are arranged in a periodic matrix in plan view.
• the pitch of one pixel 23 is, for example, the center distance between adjacent pixels 23. Further, the pitch of one pixel 23 is equal to the center distance between adjacent partition walls 24B. Furthermore, in the first embodiment, one pixel 23 has a square shape in plan view, so the pitch of one pixel 23 is equal to the maximum width W1 of one pixel 23. In the first embodiment, the maximum width W1 of one pixel 23 is set to 5 ⁇ m or more and 200 ⁇ m or less.
• the maximum width W1 of one pixel 23 is less than 5 ⁇ m, one pixel 23 becomes too small, which increases manufacturing costs. Furthermore, when the maximum width W1 of one pixel 23 exceeds 200 ⁇ m, the resolution of the exposed image decreases. In particular, it is more preferable that the maximum width W1 of one pixel 23 is 100 ⁇ m or less from the viewpoint of improving resolution. Note that in the present disclosure, the maximum width W1 of one pixel may be less than 5 ⁇ m. Further, in the present disclosure, the maximum width W1 of one pixel may exceed 200 ⁇ m.
• the maximum width W1 in the X direction and the maximum width W1 in the Y direction are equal, but in the present disclosure, the maximum width in the X direction and the maximum width in the Y direction are different. It's okay. That is, in the present disclosure, the shape of one pixel may be rectangular in plan view. Further, the shape of one pixel is not limited to a rectangular shape, and may be any geometric shape such as a circular shape or other polygonal shape.
• the optical element 26 includes a base 26A and a microlens 26B provided on one surface of the base 26A.
• the optical element 26 is arranged below the liquid tank 12 and between the light source device 24 and the liquid tank 12.
• the optical element 26 uses the light emitted from one pixel 23 to form a spot light that is irradiated onto the photocurable resin 18 .
• An exposed image is formed in the formation area 18A in the liquid tank 12 by the plurality of spot lights.
• the base 26A is a plate-like member.
• the base 26A can be made of translucent glass, resin material, or the like.
• the microlens 26B can be made of transparent glass, resin material, or the like.
• the microlens 26B of the first embodiment serves as an optical element and forms a spot light that is irradiated onto the photocurable resin 18 by condensing light emitted from one pixel 23.
• the optical element may be another light condensing device such as a type of lens other than a microlens or a reflecting mirror.
• the base 26A and the microlens 26B are integrally formed. Note that in the present disclosure, the microlens 26B may be formed separately from the base 26A and may be joined to the base 26A.
• the microlens 26B has a circular shape in plan view. Further, as shown in FIG. 2, the microlens 26B has a hemispherical shape that projects upward. In the first embodiment, all the microlenses 26B have the same diameter. Note that in the present disclosure, the shapes and dimensions of the plurality of microlenses 26B may be different. Furthermore, the shapes and dimensions of the plurality of microlenses 26B in a group corresponding to one pixel may be different from each other.
• a plurality of microlenses 26B are provided in a matrix on the base 26A in plan view.
• four microlenses 26B are arranged for one pixel 23 as one microlens array.
• the number of microlenses 26B for one pixel may be one or any number of microlenses 26B.
• the width W2 of one microlens array is approximately equal to the width W3 of the sealing material.
• the pitch of the microlenses 26B within one pixel 23 is set to be greater than or equal to the light source wavelength [nm] of the light emitting element 24C and less than or equal to the pitch of one pixel 23. If the pitch of the microlenses 26B is less than the wavelength of the light source, it becomes difficult to properly perform the light focusing function as a lens. On the other hand, when the pitch of the microlenses exceeds the pitch of one pixel, the dimensions of the microlenses become too large, which increases the burden of manufacturing costs.
• the pitch of the microlenses 26B is set to be twice or more the light source wavelength [nm] of the light emitting element 24C from the viewpoint of suppressing interference fringes.
• the pitch of the microlenses 26B can be set within a range of 800 nm or more and 1 ⁇ m or less.
• the pitch of the microlenses 26B within one pixel 23 is equal to the diameter D of the microlens 26B, as shown in FIG. substantially equal. That is, in the first embodiment, the fact that the pitch of the microlenses 26B within one pixel 23 is greater than or equal to the light source wavelength is synonymous with the fact that the diameter D of the microlenses 26B is greater than or equal to the light source wavelength.
• the ratio of the diameter of the microlenses to the pitch of the microlenses within one pixel 23 is large.
• the ratio of the diameter D of the microlens 26B to the pitch of the microlens 26B within one pixel 23 is preferably 70% or more, more preferably 80% or more, and 90% or more. More preferably, it is 95% or more.
• the ratio of the diameter D of the microlenses 26B in one pitch should be within the range of 70% or more as described above. is preferred.
• the pitch of the microlens within one pixel is equal to or greater than the wavelength. Even if the diameter of the microlens is less than the light source wavelength, if the gap between the microlenses is small, the emitted light from one pixel of the light source device can be focused. In other words, if the gap between the microlenses is small enough to condense the emitted light from one pixel, the pitch formed between adjacent microlenses within one pixel can be set to be greater than the light source wavelength. .
• the central region RC has a shape in which the outer edge of the lens is directly projected onto the modeling surface 19. Further, the peripheral region RP is located at the peripheral edge of the central region RC. The light energy irradiated to the peripheral region RP does not contribute to exposure.
• FIG. 4B when four microlenses 26B are arranged for one pixel 23, part of the light emitted from the left microlens 26B that is decentered from the optical axis C is The light reaches the overlapping region RO inside the exposed image on the adjacent right microlens 26B side. Note that in the cross-sectional view of FIG. 4B, two microlenses 26B are visible. The optical axis C of the microlens 26B is parallel to the vertical direction in FIGS. 4A and 4B. Therefore, compared to the case where only one microlens 26B is arranged as shown in FIG. 4A, the reduction in the amount of spot light that does not contribute to exposure is suppressed.
• switching element As shown in FIG. 5, in the first embodiment, a switching element 36 corresponding to each of the plurality of light emitting elements 24C is provided. Specifically, each of the plurality of pixels 23 is connected to the X electrode members X1, X2 and Y electrode members Y1, Y2 set for each pixel 23 via the corresponding switching element 36. .
• the X electrode members X1, X2 and the Y electrode members Y1, Y2 are orthogonal to each other.
• two pixels 23 arranged adjacent to each other in the left and right direction are connected to the first X electrode member X1, and in the lower row in FIG. A case is illustrated in which two pixels 23 are connected to the second X electrode member X2. Further, on the left side of FIG. 5, two pixels 23 arranged adjacent to each other in the vertical direction are connected to the first Y electrode member Y1, and on the right side of FIG. A case is illustrated in which two arranged pixels 23 are connected to the second Y electrode member Y2.
• the switching element 36 can improve the accuracy of switching between light irradiation and non-light irradiation for each target pixel 23. Note that in the present disclosure, the switching element 36 is not essential.
• a subsequent cured resin layer is laminated under the previously formed cured resin layer by irradiating light using the light irradiation device 20.
• a stereolithographic object 30 is formed by a liquid bath photopolymerization method. Note that the stereolithographic object 30 may be any industrial product.
• FIG. 6 illustrates a state in which the optically modeled object 30 being modeled is suspended by the support pin 32 extending from the lower surface of the stage 14; however, in the present disclosure, the support pin 32 is not required.
• the stage 14 is lowered into the liquid tank 12 with the stereofabricated object supported above the stage 14 in FIG. 1, thereby stacking the resin cured layers in the vertical direction.
• the stage 14 is lowered into the liquid tank 12 and the resin cured layers are stacked in the vertical direction, the light is irradiated from the upper side of the liquid tank 12 toward the upper surface of the stage 14 .
• a formation region 18A in which an exposed image is formed is located between the upper surface of the stage 14 and the liquid level of the liquid tank 12. Therefore, the upper surface of the photocurable resin 18 in the formation area 18A comes into contact with oxygen in the air. Oxygen makes it difficult for the photocurable resin 18 to harden.
• the formation area 18A is a photocurable resin 18 located below the lower surface of the stage 14 in FIG. That is, since the stage 14 blocks air, the photocurable resin 18 in the formation area 18A does not come into contact with oxygen in the air.
• the width W2 of the microlens array corresponding to one pixel 23 may be greater than or equal to the width W3 of the sealing material 24D in one pixel 23.
• a case is illustrated in which four microlenses 26B are arranged in a matrix as one microlens array for one pixel 23.
• the width W2 of one microlens array is the same as the pitch of one pixel 23, that is, the maximum width W1 of one pixel 23.
• the width W2 of the microlens array is preferably set to the pitch of one pixel 23 or less. If the width W2 of the microlens array exceeds the pitch of one pixel 23, there is a concern that light will reach the position of the exposed image corresponding to the adjacent pixel 23 even though the adjacent pixel 23 is not illuminated. There is.
• the microlens 26B may have a square shape in plan view. That is, the microlens 26B of the second modification has a rectangular parallelepiped shape. Note that in the present disclosure, the shape of the microlens can be any other geometric shape, such as a rectangular shape in plan view.
• the microlens array may be composed of nine microlenses 26B arranged in a matrix in a 3 ⁇ 3 arrangement in plan view.
• nine microlenses 26B correspond to one pixel 23.
• the pitch of the microlenses 26B by setting the upper limit value and the lower limit value of the pitch of the microlenses 26B, it is possible to both form the irradiation light necessary for exposure and suppress the burden of manufacturing costs of the optical element 26. .
• the microlens 26B can irradiate a linearized spot light. Further, a plurality of microlenses 26B are arranged for light from one pixel 23. Therefore, part of the light emitted from one microlens 26B that is decentered from the optical axis C reaches the overlapping region RO inside the exposed images on the side of the microlens 26B adjacent to one microlens 26B. . As a result, compared to the case where only one microlens 26B is disposed, reduction in the amount of spot light can be suppressed. Therefore, the cured resin layer can be precisely shaped.
• the microlenses 26B are circular, and the pitch of the microlenses 26B is at least twice the light source wavelength [nm] of the light emitting element 24C. Therefore, the light emitted from the microlens 26B does not interfere with each other, and as a result, no moire pattern is generated on the surface of the stereolithographic object.
• the resin layer has a thickness of one layer compared to when the stage 14 descends into the liquid tank 12. The energy required to form a hardened layer can be reduced.
• the resolution of the design pattern is higher than in the case of the dot matrix drive format, and as a result, the accuracy of modeling the three-dimensional object can be improved.
• the stereolithography apparatus 10 includes a liquid tank, a light source device, an aperture 38, and a stage.
• the maximum width W1 of one pixel 23 of the light source device is set to 200 ⁇ m or less.
• the stereolithography apparatus 10 has an aperture 38 disposed between the light source device and the liquid tank as an optical element instead of the microlens 26B as the optical element 26 described in the first embodiment.
• this embodiment is different from the first embodiment. That is, both a condensing device such as a microlens and a diaphragm device such as an aperture are included in the "optical element" of the present disclosure.
• Members other than the aperture 38 in the second embodiment have the same configuration and function as the members with the same name in the first embodiment. Therefore, the aperture 38 will be mainly described below, and duplicate explanations of the configurations of other members will be omitted.
• the aperture 38 is a plate-shaped aperture device having a plurality of slits 38A.
• the aperture 38 can be made of resin or the like, for example.
• the slit 38A has a rectangular shape in plan view, but in the present disclosure, the shape of the slit is not limited to this, and may be any other shape, such as an elongated oval shape.
• the aperture 38 emits spot light including straight light that is irradiated onto the photocurable resin 18 using light emitted from one pixel 23 through the slit 38A. Form. An exposed image is formed in the formation region 18A in the liquid tank 12 by the plurality of spot lights thus formed.
• the other steps in the method for manufacturing a stereolithographic object according to the second embodiment are the same as those in the method for manufacturing a stereolithographic article according to the first embodiment, and thus redundant explanation will be omitted.
• the maximum width W1 of one pixel 23 is set to 200 ⁇ m or less, so that a decrease in the directivity of light is suppressed. Therefore, compared to the case where the maximum width W1 exceeds 200 ⁇ m, it is possible to suppress a decrease in light utilization efficiency in the photocuring reaction. As a result, light usage efficiency can be improved.
• a spot light irradiated onto the photocurable resin 18 is formed using an aperture 38 having a slit 38A as an optical element.
• the aperture 38 can be manufactured at a lower cost than, for example, a condensing device such as a lens, so costs can be reduced.
• Other effects in the second embodiment are the same as those in the first embodiment, and therefore redundant explanations will be omitted.
• the optical modeling apparatus 11 includes a liquid tank 12, a stage 14, a hanging member 16 for suspending the stage 14, and a light irradiation device 50.
• stage 14 supports a resin cured layer of a photocurable resin 18 that has been cured by an exposure image that is a modeling image in which the area of the stereofabricated object to be modeled has been reduced to 1/M, and also supports the resin cured layer of the photocurable resin 18 in the vertical direction in FIG. Move to. M is a positive real number greater than 1, ie, M>1.
• the stage 14 can be raised and lowered while supporting the cured resin layer.
• the area of a stereolithographic object to be modeled means the target area of the modeling surface of each layer in the target stereolithographic object.
• each layer means “each layer in a stereolithographic object modeled by curing one layer at a time by light irradiation and laminating one after another”.
• stereolithography refers to both the final three-dimensional object as a whole and each of the plurality of resin cured layers included in the stereolithography that is being built. It can be used both to mean.
• the light irradiation device 50 is provided below the liquid tank 12 in FIG. 14, and irradiates light onto the lower surface of the stage 14 through the bottom of the liquid tank 12, which has translucency.
• the third embodiment exemplifies the case of stereolithography using the DLP method, which is a surface exposure method, the stereolithography of the present disclosure is not limited to the DLP method.
• the light irradiation device and the liquid tank may be configured to be relatively movable along the surface direction of the modeling surface 19.
• the light may be scanned by moving the light irradiation device two-dimensionally within a plane parallel to the exposure surface.
• the light irradiation device 50 includes a light source device 54 and an optical element 56 arranged between the light source device 54 and the liquid tank 12.
• the light source device 54 and the optical element 56 are integrated by a sealing case 58.
• pre-created image data for modeling is input to the light irradiation device 50.
• the light irradiation device 50 performs stereolithography toward the lower side of the stage 14 immersed in the liquid tank 12 based on the input image data for modeling.
• a light emitting element (not shown) selectively irradiates light with a predetermined wavelength necessary for
• the light source device 54 has a projection surface 55 formed by a plurality of pixels 53.
• the light source device 54 projects a modeling image N times the area of the stereolithographic object 31 to be modeled from the projection surface 55 .
• N is a positive real number greater than 1, ie, N>1.
• the area may be expanded, for example, by increasing the area of each of the plurality of pixels used, or by increasing the number of the plurality of pixels used. Furthermore, increasing the area of one pixel used and increasing the number of pixels may be combined.
• a plurality of pixels 53 included in the light source device 24 are arranged on the bottom 58A of the sealing case 58 along the X direction (that is, the left-right direction in FIG. 14). Illustrated. Furthermore, in FIG. 14, for ease of viewing, a state in which only some of the plurality of pixels 53 emit light is illustrated by broken arrows. However, during actual stereolithography, the light source device 24 is controlled so that one pixel 53 emits light appropriately according to the desired image for modeling. The light source device 24 emits light from a plurality of pixels 53 all at once.
• One pixel 53 in the third embodiment includes a light emitting element arranged on a substrate (not shown). Further, each of the plurality of light emitting elements is sealed with a sealing material (not shown) inside a region surrounded on all sides by partition walls (not shown) on the substrate. In the third embodiment, one pixel 53 has a square shape in plan view. A protective layer (not shown) is provided on the upper side of the partition wall in FIG. 14, which is the side opposite to the substrate.
• partition wall Although not shown, a plurality of partition walls are provided along each of the X direction in FIG. 14 and the Y direction extending along the direction penetrating the page of FIG. 14. Therefore, when viewed from above, the partition walls in the X direction and the partition walls in the Y direction appear in a lattice shape. Although not shown, a protective layer is provided on the partition wall in FIG. 14.
• the emission wavelength of the light emitting element can be arbitrarily set within the range of, for example, from about 365 nm in the ultraviolet region to about 1770 nm in the infrared region.
• the light emitting element is a mini LED or a micro LED, it is possible to irradiate light in the ultraviolet region of 365 nm.
• the transparency of the photocurable resin is relatively high, a sufficient curing reaction may not occur with light of wavelengths other than the ultraviolet region.
• Light having a wavelength in the ultraviolet region is advantageous in that it can easily cure the photocurable resin even if the photocurable resin has relatively high transparency.
• the optical element 56 is arranged below the liquid tank 12 and between the light source device 24 and the liquid tank 12. Note that in the present disclosure, the optical element may be placed above the liquid tank 12.
• the optical element 56 includes a reduction projection optical component 57 for a stereolithography device.
• the reduction projection optical component 57 includes a sealing case 58, a first light focusing member 57A, a second light focusing member 57B, and an optical axis correction member 57C.
• the reduction projection optical component 57 focuses the light of the modeling image 41.
• the reduction projection optical component 57 is arranged between the projection surface 55 of the light source device 24 and the bottom surface of the liquid tank 12.
• the reduction projection optical component 57 reduces the area of the printing image having an area N times the area of the stereolithographic object 31 (however, N>1) to 1/M (however, M>1).
• the image is projected onto the modeling surface 19 in the liquid tank 12 in the reduced state.
• N is 3 or more
• M is 3 or more. That is, the area of the modeling image is set to three times or more, and the reduction ratio by the reduction projection optical component 57 is set to 1/3 or less.
• the optical energy density is improved by more than 9 times compared to the case where the image for modeling of the stereolithographic object 31 is projected on the same area without changing the area, that is, on the 1 times the area. can.
• the reduction ratio is 1/4 or less from the viewpoint of improving the optical energy density.
• the reduction ratio is 1/5 or less from the viewpoint of improving the optical energy density.
• the reduction ratio of the modeling image by the reduction projection optical component is arbitrary. That is, in the present disclosure, the number of N greater than one may be less than three.
• N ⁇ M the area of the image for printing reduced and projected onto the formation area becomes smaller than the area of the first stereolithographic object before the area is enlarged, that is, the target area.
• the area of the printing image of the exposure image in the printing area may be smaller than the initial target area.
• pixel density refers to a square area whose sides are defined by two axes perpendicular to each other on the projection plane, and which is included in a unit area where each side has a length of 1 inch. This means the number of pixels in a light emitting element.
• the sealing case 58 Inside the sealing case 58, a first light focusing member 57A, a second light focusing member 57B, and an optical axis correction member 57C are each sealed.
• the sealing case 58 can be made of, for example, resin.
• the sealing case 58 has a bottom portion 58A, a peripheral wall portion 58B, and a ceiling portion 58C.
• the ceiling portion 58C has translucency.
• the shape of the peripheral wall portion 58B can be changed as appropriate as long as the members constituting the reduction projection optical component 57 can be integrally sealed inside.
• the side wall of the first light focusing member 57A may be used as a part of the peripheral wall portion 58B of the sealing case 58.
• the bottom 58A of the first light focusing member 57A may be used as part or all of the bottom of the sealing case 58. That is, the sealing case is not essential in the present disclosure.
• the first light focusing member 57A is arranged inside the sealing case 58 on the side of the light source device 24, which is the opposite side of the liquid tank 12 with the ceiling portion 58C in between.
• the first light focusing member 57A of the third embodiment is, for example, a concave focusing lens. Note that in the present disclosure, the first light focusing member 57A is not limited to a focusing lens. In the present disclosure, another member or device that has translucency and can focus the light of the modeling image 41 may be employed as the first light focusing member.
• the second light focusing member 57B is arranged between the first light focusing member 57A and the optical axis correction member 57C.
• the second light focusing member 57B of the third embodiment includes a second light focusing member 57B having a refractive index greater than the refractive index of air. Note that in the present disclosure, the refractive index of the second light focusing member may be less than or equal to the refractive index of air. Further, in the present disclosure, the second light focusing member is not essential.
• the second light focusing member 57B of the third embodiment is, for example, an acrylic or epoxy hardened material, that is, a solid material.
• the second light focusing member 57B has a refractive index different from that of the first light focusing member 57A.
• the refractive index of the second light focusing member 57B is, for example, about 1.5.
• the second light focusing member 57B is not limited to an acrylic hardened material.
• another member or device that has translucency and can focus the light of the modeling image may be employed as the second light focusing member.
• the second light focusing member 57B may be a solid or a liquid that does not have light-curable properties.
• pure water, grease, methylene iodide (CH 2 I 2 ), an organic halogen compound, an acrylic hardening material, etc. can be used as the second light focusing member 57B.
• Acrylic hardening materials are advantageous in that they are generally readily available and relatively easy to handle.
• the first light focusing member 57A and the second light focusing member 57B are in close contact with each other inside the sealing case 58. Therefore, compared to the case where a gap is formed between the first light focusing member 57A and the second light focusing member 57B due to the first light focusing member 57A and the second light focusing member 57B not coming into close contact with each other, the light The influence on the refractive index can be reduced. Note that in the present disclosure, it is not essential that the first light focusing member 57A and the second light focusing member 57B come into close contact with each other.
• the reduction projection optical component may be configured by only one of the first light focusing member 27A and the second light focusing member 57B.
• the optical axis correction member 57C adjusts the light input from the second light focusing member 57B so that the optical axis of the light focused by the first light focusing member 57A is along a direction perpendicular to the modeling surface 19 of the forming area 18A. Correct the optical axis of That is, in the present disclosure, it is not essential that the optical axis of the focused light be strictly orthogonal to the modeling surface 19. Any optical device such as a convex lens can be used as the optical axis correction member 57C. Note that in the present disclosure, the optical axis correction member is not essential.
• the first light focusing member 57A and the optical axis correction member 57C are different members from each other, but in the present disclosure, the first light focusing member and the optical axis correction member may be composed of one member.
• ⁇ Method for manufacturing optically modeled objects> (Overview of stereolithography)
• a method for manufacturing a stereolithographic object according to the third embodiment will be described with reference to FIGS. 14 and 16 to 19.
• the image data for modeling 40A having an area N times the area of the stereolithography object 31 is created in advance by a modeling image data creation device such as CAM software.
• the created image data for modeling 40A is input to the stereolithography device 11.
• a formation area including the liquid surface of the photocurable resin 18 on the lower side of the stage 14 and having a constant thickness is formed.
• the photocurable resin 18 is selectively cured by photopolymerization.
• a cured resin layer of the stereolithographic object is formed.
• the stage 14 is raised by the set thickness of the cured resin layer.
• light is irradiated using the light irradiation device 50, so that a subsequent resin cured layer is formed under the previously formed resin cured layer. are stacked.
• each resin cured layer in stereolithography of the third embodiment will be specifically described.
• the area of the modeling image data 40A in other words, the external dimensions
• the modeling image projected from the projection surface 55 of the light source device 24 are determined.
• the area of 41A is almost the same.
• the area of the image data for modeling 40B and the projection of the light source device 24 are determined.
• the area of the modeling image 41B projected from the surface 55 is approximately the same.
• the area of the modeling image 42B on the modeling surface 19 in the liquid tank 12 in which the photocurable resin 18 is accumulated is reduced to the area on the projection surface 55 by reduction projection using the reduction projection optical component 57. Compared to this, it is reduced to 1/N.
• the pattern of the subsequent second resin cured layer 31B is different from the pattern of the preceding first resin cured layer 31A.
• FIG. 19 a part of a stereolithographic object is illustrated in which a first resin cured layer 31A having a constant thickness and a second resin cured layer 31B having a constant thickness are laminated.
• a method for manufacturing a stereolithography product using the stereolithography apparatus 11 according to the third embodiment can be configured.
• the shapes of the cured resin layer in FIGS. 17 to 19 are merely examples, and in the present disclosure, the shape of the cured resin layer is not limited to these and may be arbitrary.
• the support pin 32 in FIG. 16 in the third embodiment is not essential in the present disclosure, as described in the first embodiment.
• the stage 14 for example, by lowering the stage 14 into the liquid tank 12 with the stereolithographic object supported above the stage 14 in FIG.
• a method may be adopted in which the resin cured layers are stacked in the vertical direction.
• the photocurable resin 18 is difficult to cure due to oxygen. Become.
• the stage 14 blocks air as in the first embodiment, so that the formation area 18A is The photocurable resin 18 does not come into contact with oxygen in the air.
• modeling images 41A and 41B having an area N times the area of the stereolithographic object 31 are projected from the projection surface 55 of the light source device 24. Therefore, compared to a device that projects a modeling image having an area that is one times the area of the stereolithographic object 31 from the projection plane of the light source device, the number of pixels 53 used increases by N times.
• the reduction projection optical component 57 projects the modeling images 41A and 41B onto the modeling surface 19 in the liquid tank 12 with the area reduced to 1/N.
• the light energy density in the forming area 18A as a printing area is improved compared to the case where a printing image having an area that is one times the area of the stereolithographic object 31 is directly projected onto the printing surface 19 in the liquid tank 12. can. As a result, light usage efficiency can be improved.
• the pixel density of the modeling images 41A and 41B on the modeling surface 19 in the liquid tank 12 is n times higher, the light energy density increases to the square of n (n 2 ). As a result, the modeling speed in stereolithography can be improved.
• the diagonal length of the forming area as the modeling area is approximately 5.6 inches (i.e., 70 mm), based on the general dimensions of the oral cavity. In many cases, a rectangular shaped forming surface of approximately 124 mm x 124 mm is required.
• a light source device that can actually form exposure light having a fine pixel pitch of about 50 ⁇ m is prepared, such as in the SLA (Stereolithography) method, in order to realize the fine pixel pitch, for example, a reflective micromirror, etc. , the number of additional members may increase. Therefore, the configuration of the device becomes complicated, and as a result, the cost tends to increase.
• the area of the modeling image on the light projection surface of the light source device 24 is expanded by N times. Therefore, for example, even if the dimension of the projection surface 55 in the light source device 24 is about 25 inches and the actual pixel pitch is about 250 ⁇ m, the length of the diagonal line in the reduced printing image 42 is A pixel pitch of about 50 ⁇ m can be obtained for a formation area of about 5.6 inches. As a result, even one pixel having a relatively large area can be used as a unit pixel without requiring additional members, so that the device can be constructed at a lower cost. Therefore, the optical modeling apparatus 11 according to the third embodiment is suitable for optical modeling of dental objects.
• the number of a plurality of pixels that project the modeling images 41A, 41B whose area is enlarged by N times may be increased.
• the pixel density of the modeling images 42A, 42B on the modeling surface 19 can be further improved as the number of pixels onto which the modeling images 41A, 41B are projected increases.
• the area of the modeling images 41A, 41B can be reduced to 1/N by the first light focusing member 57A. Further, the optical axis of the light can be corrected in a direction perpendicular to the modeling surface 19 by the optical axis correction member 57C.
• the overall refractive index of the reduction projection optical component 57 is formed by the combination of two light focusing members, the first light focusing member 57A and the second light focusing member 57B. Therefore, it is easier to adjust the overall refractive index of the reduction projection optical component 57 than when the reduction projection optical component 57 has only one first light focusing member 57A. Moreover, the modeling images 41A and 41B whose areas have been reduced are less likely to be distorted than when the reduction projection optical component 57 has only one first light focusing member 57A.
• the values of N of the enlargement ratio and reduction ratio are 3 or more, so even if the LED is a mass-produced light emitting element in which N is 3 or more, the light energy density can be improved.
• the resin since the cured resin layers are stacked in the vertical direction as the stage 14 rises, the resin has a thickness of one layer compared to when the stage 14 descends into the liquid tank 12. The energy required to form a hardened layer can be reduced.
• Other effects in the third embodiment are the same as those in the first and second embodiments, and therefore, redundant explanation will be omitted.
• a stereolithography apparatus 11A includes a rotation support part 34 that rotates a light irradiation device 50 including an optical element 56.
• the rotation support portion 34 is rotatable not only in the X direction extending along the left-right direction in FIG. 20 but also in the Y direction extending along the direction penetrating the plane of the paper in FIG.
• the case where the entire light irradiation device 50 including the light source device 24 and the optical element 56 is supported by the rotation support part 34 was illustrated, but the present disclosure is not limited to this, and the optical element Only 56 may be rotatably supported.
• the other configurations of the stereolithography apparatus 11A according to the fifth modification are the same as those of the stereolithography apparatus 11 according to the third embodiment, and therefore redundant explanation will be omitted.
• the optical energy density in stereolithography can be improved. Furthermore, by rotating the light irradiation device 50, the irradiation range of light can be expanded compared to, for example, a case where the light irradiation device 50 can only irradiate light perpendicular to the modeling surface 19. Other effects in the fifth modification are the same as those in the third embodiment, so repeated explanation will be omitted.
• stereolithography is realized by the DLP method
• the present disclosure is not limited to the DLP method, and may be implemented using other methods such as an LCD (Liquid Crystal Display) method or a micro LED method. It can also be applied to this method.
• the members constituting the light irradiation device are normally required to have high durability so that they can withstand relatively high light energy. Therefore, the cost tends to increase.
• the modeling image on the modeling surface is contracted more than the modeling image projected from the projection surface, it is not necessary to increase the durability of the light irradiation device as much as in the case of the DLP method. Therefore, by combining the present disclosure with, for example, an LCD method or a micro LED method, it is possible to suppress the cost of the stereolithography apparatus.
• the transmittance loss from the light source is relatively large, so it may not be possible to obtain the light energy necessary for stereolithography.
• the light energy density may remain at about 2 mJ/cm 2 .
• the DLP method can achieve a light energy density of about 16 mJ/cm 2 .
• the printing image on the printing surface is shrunk compared to the printing image projected from the projection surface into a general LCD type stereolithography apparatus, it is possible to achieve the same level as the DLP method. It becomes possible to obtain a higher light irradiation intensity. For example, when the reduction ratio is 1/2.8, that is, when an area ratio of about 8 times is obtained, assuming that no optical loss occurs, the light of about 16 mJ/cm 2 is the same as in the case of the DLP method. It is possible to obtain energy density.
• the present disclosure can be configured by partially combining the configurations illustrated in FIGS. 1 to 20.
• the present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is determined only by the matters specifying the invention in the claims that are reasonable from the above explanation. It is.

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• 2023
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