Light molding device

Abstract

To provide a light molding device that achieves both high-precision molding and a reduction in the time required for molding.SOLUTION: A light molding device includes: a molding tank 11 that has a light-transmitting plate 14 on its bottom surface and stores a photocurable resin 1 and a liquid release material 3 that has a larger specific gravity than the photocurable resin 1 and undergoes phase separation from the photocurable resin 1; a light irradiation part 20 that irradiates light through the light-transmitting plate 14 to cure the photocurable resin 1 adjusted to a predetermined thickness; a platform 12 that faces an interface 3A between the release material 3 and the photocurable resin 1 and can be raised and lowered relative to the interface 3A; and an interface height position adjusting mechanism 40 that adjusts a height position of the interface 3A according to fluctuations in an amount of the release material 3 stored in the molding tank 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a photolithography apparatus. [Background technology]

[0002] Generally, a photolithography technique is known in which a liquid photocurable resin is irradiated with light such as ultraviolet light to form a three-dimensional object made of the cured resin. Patent Document 1 discloses a photolithography technique in which a desired object is formed by stacking cured layers by repeating the following steps: irradiating a liquid photocurable resin with light corresponding to a cross-sectional shape at a predetermined height position of the object through a light-transmitting window (light-transmitting portion) provided on the bottom surface of the liquid vat in which the photocurable resin is stored, onto a base placed opposite the light-transmitting window, thereby forming a cured layer of the resin on the underside of the base in the same shape as the predetermined cross section; and lifting the base up by a predetermined height relative to the liquid vat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-62841 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional configuration, the cured layer formed by curing the photocurable resin is formed in close contact with the light-transmitting window of the liquid vat, and therefore, before the process of lifting the base upward relative to the liquid vat, it is necessary to peel the cured layer from the light-transmitting window each time. As a result, not only is the time required for photolithography long, but there is also a risk of the object being damaged during peeling, and there is room for improvement in terms of achieving high-precision modeling.

[0005] The present invention has been made in view of the above, and has an object to provide an optical shaping apparatus that achieves both high-precision shaping and a reduction in the time required for shaping. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the optical molding apparatus of the present invention comprises: a modeling tank having a light-transmitting portion on its bottom surface and storing a photocurable resin and a liquid release material that has a specific gravity greater than that of the photocurable resin and that phase-separates from the photocurable resin; a light irradiation portion that irradiates light that cures the photocurable resin adjusted to a predetermined thickness through the light-transmitting portion; a platform that faces the interface between the release material and the photocurable resin and is capable of rising and falling relative to this interface; and an interface height position adjustment mechanism that adjusts the height position of the interface in accordance with changes in the amount of release material stored in the modeling tank. [Effects of the Invention]

[0007] According to the present invention, it is possible to achieve both highly accurate modeling and a reduction in the time required for modeling. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the basic configuration of a photo-fabrication apparatus according to the first embodiment. [Figure 2] FIG. 2 is a table defining the relationship between the determined resolution, the height position of the interface, and the distance between the platform and the interface. [Figure 3] FIG. 3 is a schematic diagram of a stereolithography device in which the interface of the release material is lowered and the distance between the platform and the interface is shortened. [Figure 4] FIG. 4 is a schematic diagram of a stereolithography device in which the interface of the release material is elevated and the distance between the platform and the interface is increased. [Figure 5] FIG. 5 is a schematic diagram showing the basic configuration of a photo-fabrication apparatus according to the second embodiment. [Figure 6] FIG. 6 is a diagram illustrating the steps of the method for manufacturing a shaped object according to the second embodiment. [Figure 7] FIG. 7 is a diagram illustrating the steps of the method for manufacturing a shaped object according to the second embodiment. [Figure 8] FIG. 8 is a diagram illustrating the steps of the method for manufacturing a shaped object according to the second embodiment. [Figure 9] FIG. 9 is a diagram illustrating the steps of the method for manufacturing a shaped object according to the second embodiment. [Figure 10] FIG. 10 is a diagram for explaining the procedure of a method for manufacturing a shaped object according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments, and when there are multiple embodiments, the present invention also includes configurations that combine the embodiments. In the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0010] In the following description of the embodiments, unless otherwise specified, uncured (uncured) liquid photocurable resin will be simply referred to as photocurable resin. A layer of photocurable resin of a predetermined thickness that is provided between a platform (described below) or a molded object held on the platform and a release material and that will be cured by light irradiation will be referred to as a photocurable resin layer or simply a resin layer. A photo-fabricated object formed by curing a liquid photocurable resin will be referred to as a three-dimensional object or simply a molded object. This three-dimensional object is not limited to a finished product in which all of the multiple cured layers are stacked, but also includes an unfinished product in which only intermediate cured layers have been stacked.

[0011] [First embodiment] FIG. 1 is a schematic diagram showing the basic configuration of a stereolithography apparatus according to a first embodiment. FIG. 2 is a table defining the relationship between the determined resolution, the height position of the interface, and the distance between the platform and the interface. FIG. 3 is a schematic diagram of a stereolithography apparatus in which the interface of the release material is lowered and the distance between the platform and the interface is shortened. FIG. 4 is a schematic diagram of a stereolithography apparatus in which the interface of the release material is higher and the distance between the platform and the interface is lengthened. As shown in FIG. 1, the stereolithography apparatus 10 includes a modeling tank 11, a platform 12, a light irradiation unit 20, a control device 30, an interface height position adjustment mechanism 40, and a resin supply mechanism 50.

[0012] The modeling tank 11 has a dish shape with an open top, and is capable of storing a liquid photocurable resin 1 and a liquid release material 3 that phase-separates from the photocurable resin 1. The modeling tank 11 has a light-transmitting plate (light-transmitting portion) 14 on its bottom surface. The light-transmitting plate 14 transmits light that cures the photocurable resin 1, and further has a curved top surface 14A. This allows, for example, the effect of correcting aberrations that differ for each wavelength for light that passes through the light-transmitting plate 14 to be achieved. The top surface 14A of the light-transmitting plate 14 may also be flat.

[0013] The photocurable resin 1 is the raw material of the three-dimensional object 2. The photocurable resin 1 is a photocurable fluid resin material that is cured by a specific light (e.g., X-rays, ultraviolet light, or visible light), and preferably contains three elements: an oligomer (e.g., epoxy acrylate, urethane acrylate, etc.), a reactive diluent (e.g., ethylenically unsaturated monomer, etc.), and a photopolymerization initiator (e.g., a benzoin-based or acetophenone-based compound, etc.).

[0014] The release material 3 is interposed between the light-transmitting plate 14 and the photocurable resin 1, and enables the cured photocurable resin 1 (model 2) to be easily released (peeled off). The release material 3 is a transparent liquid substance that is liquid at room temperature (e.g., 25°C). It has a higher specific gravity and lower viscosity than the photocurable resin 1, and undergoes phase separation from the photocurable resin 1. It is preferable that the release material 3 is incompatible with the photocurable resin 1 so that even if the release material 3 and the photocurable resin 1 are stirred, the release material 3 and the photocurable resin 1 will phase separate again, and a clear interface will be formed between the release material 3 and the photocurable resin 1. In this embodiment, the release material 3 has a higher specific gravity than the photocurable resin 1. Therefore, as shown in FIG. 1, the release material 3 is stored below the modeling tank 11, and the photocurable resin 1 is stored above the release material 3. Therefore, an interface 3A is formed between the release material 3 and the photocurable resin 1. The release material 3 may be a liquid material (for example, saline solution) that is inactive to the photocurable resin 1 and the light that hardens the photocurable resin 1.

[0015] Furthermore, the release material 3 has the property that the amount of light transmitted through the release material 3 varies depending on the height (depth) from the light-transmitting plate 14 to the interface 3A with the photocurable resin 1, i.e., the height position of the interface 3A with the photocurable resin 1. The release material 3 contains, for example, a light absorber (a water-soluble light absorber in this embodiment) that absorbs the light, and this light absorber effectively absorbs the light. Therefore, by changing the height position of the interface 3A with the photocurable resin 1, the amount of light transmitted through the release material 3 can be varied; increasing the height position of the interface 3A reduces the amount of light transmitted, and decreasing the height position of the interface 3A increases the amount of light transmitted.

[0016] According to the inventor's intensive research, it has been found that when the amount of light transmission is reduced, excess light is not irradiated onto the photocurable resin 1, and the thickness of the cured photocurable resin layer can be reduced, thereby achieving high-precision photolithography. It has also been found that when the amount of light transmission is reduced, high-resolution modeling can also be achieved in the horizontal direction. On the other hand, it has also been found that when the amount of light transmission is increased, more light is irradiated onto the photocurable resin 1, and the thickness of the cured photocurable resin layer can be increased, thereby achieving high-speed photolithography. In this way, by adjusting the height position of the interface between the release material 3 and the photocurable resin 1, it is possible to achieve both high-precision and high-speed modeling of the modeled object.

[0017] The platform 12 holds the object 2 formed from the cured photocurable resin 1, and is disposed above the modeling tank 11, facing the light-transmitting plate 14. The platform 12 is formed in the shape of a polygonal plate, such as a disk or a square plate, and is disposed so that its lower surface 12A is substantially parallel to the interface 3A between the release material 3 and the photocurable resin 1. The platform 12 is also connected to a platform lifting mechanism 15, and is provided so that it can be raised and lowered relative to the modeling tank 11 by the operation of this platform lifting mechanism 15. Specifically, the platform 12 can move toward and away from the interface 3A, and holds the object 2 formed on the lower surface 12A that faces the interface 3A.

[0018] The light irradiation unit 20 is disposed below the modeling tank 11, i.e., on the opposite side of the platform 12 across the light-transmitting plate 14. The light irradiation unit 20 irradiates the photocurable resin 1 with light L, which cures the photocurable resin 1, through the light-transmitting plate 14 and the release material 3. The irradiated light L may be any light capable of curing the photocurable resin 1, and may be, for example, ultraviolet light or short-wavelength visible light. The light irradiation unit 20 includes a light source 21, an illumination lens (illumination optical system) 22, polarizing plates 23 and 24, a λ / 4 plate 26, an image forming element (light modulation element) 27, a reflecting mirror 25, and a projection lens 28.

[0019] The light source 21 emits light to be irradiated onto the image forming element 27, and may be, for example, an ultraviolet lamp or an LED (Light Emitting Diode) lamp. The illumination lens 22 homogenizes the illuminance of the light, such as ultraviolet light, emitted from the light source 21. The polarizers 23 and 24 have the property of reflecting either s-polarized light or p-polarized light and transmitting the other. In the example of FIG. 1, the polarizer 23 transmits p-polarized light and reflects s-polarized light, while the polarizer 24 transmits s-polarized light and reflects p-polarized light. The polarizers 23 and 24 are, for example, wire-grid polarizers.

[0020] The λ / 4 plate 26 is a retardation plate that converts either s-polarized light or p-polarized light into the other by passing the light twice, once incident and once reflected. In the example of FIG. 1, the λ / 4 plate 26 converts p-polarized light into s-polarized light. The image forming element 27 modulates light according to cross-sectional shape data of each layer (at a predetermined height position) to be formed in the object 2, and may be, for example, an LCOS (Liquid Crystal On Silicon) device, a Digital Mirror Device (DMD), or a liquid crystal device.

[0021] The reflecting mirror 25 reflects the light modulated by the image forming element 27 toward the projection lens 28. The reflecting mirror 25 reflects either s-polarized light or p-polarized light and transmits the other. In the example of FIG. 1, the reflecting mirror 25 transmits p-polarized light and reflects s-polarized light. The projection lens 28 forms an image from the light reflected by the reflecting mirror 25.

[0022] The interface height position adjustment mechanism 40 adjusts the height position of the interface 3A according to fluctuations in the amount of the release material 3 stored in the modeling tank 11. The height position of this interface 3A refers to the height position relative to a predetermined reference position of the modeling tank 11 (for example, the lowest point of the upper surface 14A of the light-transmitting plate 14 or the upper end surface 11A of the modeling tank 11). The interface height position adjustment mechanism 40 includes an interface sensor 41 that detects the height position of the interface 3A, a storage unit 42 that is connected to the modeling tank 11 via a first communication hole 11B provided at the bottom of the modeling tank 11, and a pressing unit 43 that presses the release material 3 in the storage unit 42.

[0023] The interface sensor 41 is provided on the inner wall of the modeling tank 11. The interface sensor 41 detects the height position of the interface 3A based on, for example, differences in the refractive index, reflectance, and conductivity between the photocurable resin 1 and the release material 3. While one interface sensor 41 is illustrated in FIG. 1 as an example, a configuration in which multiple interface sensors are arranged in the height direction may be used. The storage section 42 is a section that temporarily stores the release material 3 that flows in from the modeling tank 11 or flows out to the modeling tank 11 through the first communication hole 11B. The pressing section 43 is arranged slidably in the height direction between the storage section 42 and the inner wall thereof via an airtight member (packing). For example, when the space above the pressing unit 43 in the storage unit 42 is closed and the pressure (air pressure) in this upper space is increased to press the pressing unit 43 downward, the release material 3 in the storage unit 42 flows out into the modeling tank 11 through the first communication hole 11B, and the height position of the interface 3A between the release material 3 in the modeling tank 11 and the photocurable resin 1 rises. Also, when the pressure (air pressure) in the upper space is decreased (for example, to below atmospheric pressure) and the pressing unit 43 is pulled upward, the release material 3 in the modeling tank 11 flows into the storage unit 42 through the first communication hole 11B, and the height position of the interface 3A between the release material 3 in the modeling tank 11 and the photocurable resin 1 falls. Note that existing technology can be applied to the mechanism for raising and lowering the pressing unit 43 relative to the storage unit 42.

[0024] The resin supply mechanism 50 supplies the photocurable resin 1 to the modeling tank 11. In this embodiment, the resin supply mechanism 50 includes a liquid level sensor 51 that detects the liquid level of the photocurable resin 1 stored in the modeling tank 11, a supply pipe 52 that is connected to the modeling tank 11 via a second communication hole 11C provided in the modeling tank 11, and a resin supply pump 53 that is connected to the supply pipe 52.

[0025] The liquid level sensor 51 is a sensor that detects whether a predetermined amount of photocurable resin 1 is stored in the modeling tank 11, and is provided on the inner wall of the modeling tank 11 above the second communication hole 11C. The second communication hole 11C serves as a supply port for the photocurable resin 1 to the modeling tank 11, and is preferably formed at a position higher than the upper limit setting position of the interface 3A of the release material 3. The resin supply pump 53 is, for example, a metering pump that can set the supply amount (discharge amount) of the photocurable resin 1 per unit time. For example, when the liquid level sensor 51 detects the liquid level of the photocurable resin 1, the resin supply pump 53 stops supplying the photocurable resin 1.

[0026] In this embodiment, the optical shaping apparatus 10 includes a modeling tank 11 that stores a photocurable resin 1 and a liquid release material 3 that has a larger specific gravity than the photocurable resin 1 and undergoes phase separation from the photocurable resin 1, and a platform 12 that faces an interface 3A between the release material 3 and the photocurable resin 1 and is movable up and down relative to this interface 3A. Optical shaping is performed by irradiating the photocurable resin 1 with light through the release material 3. Specifically, as shown in FIG. 1 , the optical shaping apparatus 10 forms a photocurable resin layer of a predetermined thickness t made of the photocurable resin 1 between the platform 12 or the object 2 and the interface 3A, and irradiates the photocurable resin layer with light of a predetermined cross-sectional shape modulated by an image forming element 27. This predetermined thickness t is set to the thickness of one layer of the cured layer to be formed (for example, several μm to approximately 100 μm). In this configuration, the photocurable resin layer having the predetermined thickness t is cured on the release material 3, which is phase-separated from each other, so the cured layer and the release material 3 do not come into close contact with each other after curing. Therefore, by lifting the platform 12 by a distance equal to the predetermined thickness t, each photocurable resin layer having the predetermined thickness t can be formed again between the platform 12 or the object 2 and the interface 3A. In this manner, in this embodiment, the photocurable resin is prevented from coming into close contact with the light-transmitting plate of the modeling tank during curing, eliminating the need to peel the cured layer from the light-transmitting plate each time before lifting the platform upward, as in the conventional method. Therefore, in addition to shortening the time required for stereolithography, damage to the object during peeling can be prevented, achieving both high-precision modeling and a shorter modeling time.

[0027] Furthermore, in this embodiment, the optical shaping apparatus 10 has a liquid release material 3, which phase-separates from the photocurable resin 1, interposed between the light-transmitting plate 14 and the photocurable resin 1. Therefore, the upper surface 14A of the light-transmitting plate 14 does not need to be flat, and this upper surface 14A is formed into a curved surface having a predetermined optical function. Specifically, the upper surface 14A of the light-transmitting plate 14 is curved to have a lens function, and can, for example, exhibit the effect of correcting aberrations that differ depending on the wavelength of the irradiated light.

[0028] The control device 30 is an arithmetic processing device configured with, for example, a CPU (Central Processing Unit), and is connected to each part of the optical shaping apparatus 10 to control their operation. The control device 30 stores a program related to a manufacturing method for manufacturing the object 2, loads this program into memory, and executes the instructions included in the program. The control device 30 includes an internal memory (not shown), which is used for temporary storage of data such as the program in the control device 30.

[0029] The control device 30 includes a lifting / lowering control unit 31, an irradiation control unit 32, a resin supply control unit 33, a data storage unit 34, a resolution determination unit 35, an interface height control unit 36, and a thickness adjustment unit 37. The lifting / lowering control unit 31 controls the operation of the platform lifting mechanism 15 to control the height position of the platform 12. Specifically, the lifting / lowering control unit 31 raises and lowers the platform 12 based on the adjustment result of the thickness adjustment unit 37, thereby forming a photocurable resin layer adjusted to a predetermined thickness t between the platform 12 or the object 2 and the interface 3A.

[0030] The irradiation control unit 32 calculates a light irradiation pattern that indicates the cross-sectional shape of the object 2 at each predetermined height position, for example, based on the three-dimensional shape data, and controls the light source 21, the image forming element 27, etc. to irradiate the light onto the photocurable resin. Therefore, the irradiation control unit 32 can form a cured layer of a predetermined thickness by irradiating the photocurable resin layer between the interface 3A with light that corresponds to the cross-sectional shape of each layer (predetermined height position) of the object 2.

[0031] The resin supply control unit 33 controls the operation of supplying the photocurable resin 1 to the modeling tank 11. Specifically, the resin supply control unit 33 controls the operation of the resin supply pump 53 based on the detection result of the liquid level sensor 51, thereby controlling the supply amount of the photocurable resin 1. For example, when the liquid level sensor 51 detects the liquid level of the photocurable resin 1, the resin supply control unit 33 stops the operation of the resin supply pump 53 and stops the supply of the photocurable resin 1.

[0032] The data storage unit 34 stores design image data that defines the cross-sectional shape of each layer (at each predetermined height position) when forming the target object 2. If the target object 2 is formed of k layers (k is a natural number), the data storage unit 34 stores design image data that defines the cross-sectional shapes of all layers from the first layer to the kth layer.

[0033] The resolution determination unit 35 determines the resolution (detail) of the cross-sectional shape of the layer to be modeled based on the design image data stored in the data storage unit 34. Here, resolution refers to the minimum design dimension of the design image data in the horizontal direction of the cross-sectional shape of the layer (height position) to be modeled. The resolution determination unit 35 determines the resolution to be normal if this minimum design dimension is within a predetermined reference range (e.g., 500 μm to 1000 μm). Furthermore, the resolution determination unit 35 determines the resolution to be high (fine) if the minimum design dimension is smaller than the above-mentioned reference range. Furthermore, the resolution determination unit 35 determines the resolution to be low (coarse) if the minimum design dimension is larger than the above-mentioned reference range. This reference range is merely an example, and may be changed as appropriate depending on the target object 2. In this embodiment, the resolution is divided into three levels: normal, high, and low. However, more detailed divisions may be used.

[0034] The interface height control unit 36 ​​controls the operation of the interface height position adjustment mechanism 40 in accordance with the definition determined by the definition determination unit 35, and adjusts the height position of the interface 3A according to fluctuations in the amount of release material 3 stored in the modeling tank 11. Specifically, when the definition is determined to be normal, the interface height control unit 36 ​​adjusts the height position of the interface 3A to a reference height position. This reference height position is set, for example, so that the amount of light transmitted through the release material 3 falls within a reference range. When the definition is determined to be high, the interface height control unit 36 ​​adjusts the height position of the interface 3A to a position higher than the reference height position, and when the definition is determined to be low, the interface height control unit 36 ​​adjusts the height position of the interface 3A to a position lower than the reference height position. Here, in this embodiment, table data such as that shown in Figure 2 is stored in the data storage unit 34, and the interface height control unit 36 ​​is configured to obtain data regarding the height position of the interface 3A from the table data in accordance with the resolution determined by the resolution determination unit 35, but the interface height control unit 36 ​​may also calculate the height position data each time.

[0035] The thickness adjustment unit 37 adjusts the thickness of the photocurable resin 1 between the interface 3A of the release material 3 and the platform 12 or the object 2, depending on the definition determined by the definition determination unit 35. In this case, the thickness of the photocurable resin 1 is adjusted by adjusting the height position of the interface 3A described above to a thickness that minimizes the effect of the light energy of the light irradiation unit 20 on the layers to be modeled (i.e., prevents excessive curing reactions). Specifically, if the definition is determined to be normal, the thickness adjustment unit 37 adjusts the thickness of the photocurable resin 1 to a predetermined reference range (e.g., 50 μm to 100 μm). If the definition is determined to be high, the thickness adjustment unit 37 adjusts the thickness of the photocurable resin 1 to a value thinner than the reference range (e.g., 25 μm). If the definition is determined to be low, the thickness adjustment unit 37 adjusts the thickness of the photocurable resin 1 to a value thicker than the reference range (e.g., 200 μm). 2 is stored in the data storage unit 34, and the thickness adjustment unit 37 acquires data on the thickness of the photocurable resin 1 from the table data in accordance with the resolution determined by the resolution determination unit 35. Alternatively, the thickness adjustment unit 37 may calculate the thickness of the photocurable resin 1 each time. In this embodiment, the lift control unit 31 adjusts the distance between the platform 12 and the interface 3A based on the adjustment result of the thickness adjustment unit 37.

[0036] As described above, in this embodiment, when the cross-sectional shape of the layer to be modeled has low definition, the optical modeling apparatus 10 adjusts the height position of the interface 3A between the release material 3 and the photocurable resin 1 to a position lower than the reference height position, and adjusts the distance between the platform 12 and the interface 3A so that the thickness of the photocurable resin 1 becomes a value (t1) thicker than the reference range, as shown in Fig. 3. With this configuration, the amount of light transmitted through the release material 3 can be increased to efficiently harden the photocurable resin 1 that has been adjusted to a thick thickness, thereby enabling, for example, high-speed modeling of low-definition parts.

[0037] Furthermore, when the cross-sectional shape of the layer to be modeled has high resolution, as shown in FIG. 4, the height position of the interface 3A between the release material 3 and the photocurable resin 1 is adjusted to a position higher than the reference height position, and the distance between the platform 12 and the interface 3A is adjusted so that the thickness of the photocurable resin 1 is a value (t2) thinner than the reference range. This configuration reduces the amount of light transmitted through the release material 3, preventing excess light from reaching the photocurable resin 1. This allows the thinly adjusted photocurable resin 1 to be cured with high precision, and allows, for example, highly detailed parts to be modeled with high precision. Therefore, by combining these methods depending on the above-mentioned resolution, it is possible to more effectively achieve both high-precision modeling and a reduction in the time required for modeling.

[0038] As described above, the optical molding apparatus 10 according to the first embodiment includes a modeling tank 11 having a light-transmitting plate 14 on its bottom surface and storing a photocurable resin 1 and a liquid release material 3 that has a specific gravity greater than that of the photocurable resin 1 and that undergoes phase separation from the photocurable resin 1, a light irradiation unit 20 that irradiates the photocurable resin 1, adjusted to a predetermined thickness, with light to cure the photocurable resin 1 through the light-transmitting plate 14, a platform 12 that faces an interface 3A between the release material 3 and the photocurable resin 1 and is movable up and down relative to this interface 3A, and an interface height position adjustment mechanism 40 that adjusts the height position of the interface 3A in response to fluctuations in the amount of release material 3 stored in the modeling tank 11. With this configuration, the interface height position adjustment mechanism 40 accurately adjusts the height position of the interface 3A, thereby accurately controlling the position of the platform 12 relative to the interface 3A. This makes it possible to accurately adjust the thickness of the photocurable resin 1 located on the interface 3A and accurately mold the object 2. Furthermore, since the release material 3 is interposed between the photocurable resin 1 and the light-transmitting plate 14, the photocurable resin 1 is prevented from coming into close contact with the light-transmitting plate 14 when cured, and this eliminates the need to peel the cured layer of the photocurable resin 1 from the light-transmitting plate 14 each time before lifting the platform 12. Therefore, in addition to shortening the time required for stereolithography, it is possible to prevent damage to the modeled object during peeling, and it is possible to achieve both highly accurate modeling and a shortened time required for modeling.

[0039] Furthermore, the upper surface 14A of the light-transmitting plate 14 facing the release material 3 is formed in a curved shape having a predetermined optical effect, so that, for example, it is possible to correct aberrations that differ for each wavelength for light that passes through the light-transmitting plate 14.

[0040] The release material 3 has a property in which the amount of light transmitted through the release material 3 varies depending on the height position of the interface 3A. The control device 30 includes a resolution determination unit 35 (controller 30) that determines the resolution of the cross-sectional shape at a height position to be modeled based on design image data that defines the cross-sectional shape of the object 2 to be modeled by irradiating light at each predetermined height position. The interface height position adjustment mechanism 40 adjusts the height position of the interface 3A depending on the determined resolution. With this configuration, the amount of light transmitted through the release material 3 varies by adjusting the height position of the interface 3A depending on the determined resolution. Therefore, for example, when the resolution is high, a high-resolution portion can be modeled with high accuracy by increasing the height position of the interface 3A and thinning the thickness of the photocurable resin 1. On the other hand, when the resolution is low, for example, by lowering the height position of the interface 3A and thickening the thickness of the photocurable resin 1, the amount of object modeled per unit time (thickness of the object) can be increased, thereby realizing high-speed modeling. This makes it possible to achieve both high precision and high speed modeling of the object.

[0041] Furthermore, if the resolution is determined to be high, the interface height position adjustment mechanism 40 adjusts the height position of the interface 3A to a position higher than a predetermined reference height, and if the resolution is determined to be low, it adjusts the height position of the interface to a position lower than the reference height, thereby making it possible to appropriately adjust the amount of light transmitted through the release material 3 to the photocurable resin 1.

[0042] Furthermore, if the platform 12 determines that the degree of definition is high, it adjusts the thickness of the photocurable resin 1 to a value thinner than a predetermined reference range, and if the platform 12 determines that the degree of definition is low, it adjusts the thickness to a value thicker than the reference range, so that the thickness of the photocurable resin 1 can be adjusted to an appropriate value that matches the amount of light transmittance.

[0043] [Second embodiment] Next, a photo-fabrication apparatus according to a second embodiment will be described. Fig. 5 is a schematic diagram showing the basic configuration of the photo-fabrication apparatus according to the second embodiment. The same components as those in the above-described embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0044] In the optical shaping apparatus of the first embodiment described above, the release material 3 is interposed between the photocurable resin 1 and the light-transmitting plate 14, eliminating the need to peel off the cured layer of the photocurable resin 1 from the light-transmitting plate 14. This not only shortens the time required for optical shaping, but also prevents damage to the object during peeling. On the other hand, in the case where a part of the object protrudes toward the platform 12 and a gap is formed between this protruding part and the object on the platform 12 side, conventionally, it has been necessary to sequentially model the part including the gap from the platform 12 side and then later remove the support part corresponding to the gap, which can complicate the modeling process.

[0045] Therefore, in this second embodiment, the optical shaping apparatus 100 forms, in a simple process, a shaped object 2 having a first shaped object 2A formed downward from the platform 12 and a second shaped object 2B protruding upward toward the platform 12 at a position higher than the lowermost surface of the first shaped object 2A, without later removing the support portion. As shown in Fig. 5, the optical shaping apparatus 100 includes a shaping tank 11, a platform 12, a light irradiation unit 20, a control device (optical shaping control device) 130, an interface height position adjustment mechanism 40, and a resin supply mechanism 60.

[0046] The interface height position adjustment mechanism 40 has the same configuration as in the first embodiment, but its operation differs in that in this embodiment, the height position of the interface 3A is maintained at a constant height without changing. In this embodiment, when the second object 2B is formed, part of the object 2 sinks into the release material 3, and the height position of the interface 3A of the release material 3 fluctuates slightly depending on the volume of this sunken object 2. For this reason, the interface height position adjustment mechanism 40 controls the operation of the pressing unit 43 based on the detection result of the interface sensor 41 so as to maintain the interface 3A at a constant height.

[0047] Similar to the first embodiment, the resin supply mechanism 60 supplies the photocurable resin 1 to the modeling tank 11. In this embodiment, the resin supply mechanism 60 includes a first liquid level sensor 61 that detects the liquid level of the photocurable resin 1 stored in the modeling tank 11, a supply pipe 62 that is connected to the modeling tank 11 via a second communication hole 11C provided in the modeling tank 11, a resin supply / discharge pump 63 that is connected to the supply pipe 62, and a second liquid level sensor 64 that is provided at a position lower than the first liquid level sensor 61 and detects the liquid level of the photocurable resin 1.

[0048] Similar to the liquid level sensor 51 in the first embodiment, the first liquid level sensor 61 is a sensor that detects whether a predetermined amount of photocurable resin 1 is stored in the modeling tank 11. In this embodiment, the first liquid level sensor 61 is used to control the liquid level of the photocurable resin 1 in the modeling tank 11 when modeling the first object 2A by a so-called regulated liquid level method.

[0049] The second liquid level sensor 64 is a sensor that detects whether a predetermined amount of photocurable resin 1 is stored in the modeling tank 11. Specifically, the second liquid level sensor 64 is provided at a position that is a predetermined thickness t (the thickness of one layer of the cured layer to be formed, for example, several μm to 100 μm) higher than the height position of the interface 3A. In this embodiment, the second liquid level sensor 64 is used to control the liquid level of the photocurable resin 1 in the modeling tank 11 when modeling the second object 2B by a so-called free liquid level method.

[0050] The resin supply / discharge pump 63 is a pump that has the function of supplying the photocurable resin 1 to the modeling tank 11 while discharging excess photocurable resin 1 from the modeling tank 11. In this case, a configuration in which the supply pump and the discharge pump are provided separately may be provided. For example, when modeling the first object 2A, the resin supply / discharge pump 63 stops supplying the photocurable resin 1 when the first liquid level sensor 61 detects the liquid level of the photocurable resin 1. Furthermore, for example, when modeling the second object 2B, the resin supply / discharge pump 63 supplies or discharges the photocurable resin 1 according to the detection result of the second liquid level sensor 64, and operates so that the liquid level of the photocurable resin 1 becomes a predetermined thickness t with respect to the height position of the interface 3A.

[0051] Like the control device 30 described above, the control device 130 is an arithmetic processing device including, for example, a CPU (Central Processing Unit), and is connected to each part of the optical shaping apparatus 100 to control their operation. The control device 130 stores a program related to a manufacturing method for manufacturing the object 2 (first object 2A and second object 2B), loads the program into memory, and executes instructions included in the program. The control device 130 includes an internal memory (not shown), which is used for temporary storage of data such as the program in the control device 130.

[0052] The control device 130 includes a lift control unit 131, an irradiation control unit 132, a resin supply control unit 133, a data storage unit 134, an interface height control unit 135, and a modeling control unit 136. The lift control unit 131 controls the operation of the platform lifting mechanism 15 to control the height position of the platform 12. Specifically, when modeling the first object 2A, the lift control unit 131 raises and lowers the platform 12 to form a photocurable resin layer with a predetermined thickness t between the platform 12 or the object 2 and the interface 3A. When modeling the second object 2B, the lift control unit 131 lowers the platform 12 so that a part of the object 2 being modeled is submerged in the release material 3. For example, the target surface on which the second object 2B is to be modeled is aligned with the interface 3A of the release material 3, and a photocurable resin layer with a predetermined thickness t is formed on this interface 3A.

[0053] The irradiation control unit 132 calculates a light irradiation pattern that indicates the cross-sectional shape of the object 2 (first object 2A and second object 2B) at each predetermined height position based on, for example, the three-dimensional shape data, and controls the light source 21, the image forming element 27, etc. to irradiate the light onto the photocurable resin. Therefore, the irradiation control unit 132 can form a cured layer of a predetermined thickness by irradiating the photocurable resin layer, which has been adjusted to a predetermined thickness, with light that corresponds to the cross-sectional shape of each layer (predetermined height position) of the object 2.

[0054] The resin supply control unit 133 controls the operation of supplying or discharging the photocurable resin 1 to or from the modeling tank 11. Specifically, when modeling the first object 2A, the resin supply control unit 133 controls the operation of the resin supply / discharge pump 63 based on the detection result of the first liquid level sensor 61, thereby controlling the supply amount of the photocurable resin 1. For example, when the first liquid level sensor 61 detects the liquid level of the photocurable resin 1, the resin supply control unit 133 stops the operation of the resin supply / discharge pump 63 to stop the supply of the photocurable resin 1. Furthermore, when modeling the second object 2B, the resin supply control unit 133 controls the operation of the resin supply / discharge pump 63 based on the detection result of the second liquid level sensor 64, thereby supplying or discharging the photocurable resin 1, and adjusting the liquid level of the photocurable resin 1 to a predetermined thickness t relative to the height position of the interface 3A.

[0055] The data storage unit 134 stores design image data that defines the cross-sectional shape of each layer (at each predetermined height position) when forming the target object 2 (first object 2A and second object 2B). If the target object 2 is formed of k layers (k is a natural number), the data storage unit 134 stores design image data that defines the cross-sectional shapes of all layers from the first layer to the kth layer.

[0056] The interface height control unit 135 controls the operation of the interface height position adjustment mechanism 40 to adjust the height of the interface 3A to a constant position depending on fluctuations in the amount of release material 3 stored in the modeling tank 11. Specifically, when modeling the first object 2A, the interface height control unit 36 ​​controls the operation of the pressing unit 43 based on the detection result of the interface sensor 41 so that the interface 3A maintains a constant height position. Furthermore, when modeling the second object 2B, part of the object 2 sinks into the release material 3, and the height position of the interface 3A of the release material 3 fluctuates slightly depending on the volume of the sunken object 2. For this reason, the interface height control unit 36 ​​controls the operation of the pressing unit 43 based on the detection result of the interface sensor 41 so that the interface 3A maintains a constant height position.

[0057] The modeling control unit 136 controls the elevation control unit 131, the irradiation control unit 132, the resin supply control unit 133, the data storage unit 134, and the interface height control unit 135, and controls the overall modeling operation of the optical modeling apparatus 100. Specifically, the modeling control unit 136 controls the optical modeling apparatus 100 to perform the following operations: modeling a first object 2A by irradiating light onto the first object 2A while raising the platform 12 relative to the interface 3A, and modeling a second object 2B by irradiating light onto the second object 2A while lowering the platform 12 relative to the interface 3A to sink at least a portion of the first object 2A into the release material 3, and then further lowering the platform 12 relative to the interface 3A to form a second object 2B by irradiating light onto the second object 2B while further lowering the platform 12 relative to the interface 3A.

[0058] Next, a method for manufacturing a molded object according to the second embodiment will be described with reference to FIGS. 6 to 9. These figures schematically show a portion of the optical molding apparatus 100 shown in FIG. 5. First, a first molded object 2A is molded. When molding the first molded object 2A, the molding control unit 136 controls the operation of the pressing unit 43 via the interface height control unit 36, and maintains the interface 3A at a constant height based on the detection result of the interface sensor 41. The molding control unit 136 also controls the operation of the resin supply / discharge pump 63 via the resin supply control unit 133, and supplies the photocurable resin 1 to the molding tank 11 until the first liquid level sensor 61 detects the liquid level of the photocurable resin 1. As shown in FIG. 6, the molding control unit 136 also raises the platform 12 via the elevation control unit 131, and positions the platform 12 at a position where the distance between the bottom surface of the first molded object 2A held on the platform 12 and the interface 3A of the release material 3 is a predetermined distance t. In this case, a photocurable resin layer having a predetermined thickness t, which is the same as the predetermined distance t, is formed between the lowermost surface of the first object 2A and the interface 3A of the release material 3.

[0059] Next, the forming control unit 136 causes the irradiation control unit 132 to calculate an irradiation pattern that indicates the cross-sectional shape of the target first object 2A at a predetermined height, based on the three-dimensional shape data of this first object 2A, and irradiates the photocurable resin layer with light L that corresponds to the cross-sectional shape of the layer (kth layer) at the target height through the light-transmitting plate 14. As a result, the photocurable resin layer is cured to have the same cross-sectional shape as the kth layer. Therefore, as shown in FIG. 6, a cured layer of a predetermined thickness t is further formed on the bottom surface of the first object 2A.

[0060] The formation control unit 136 repeats the above-described procedure until the formation of the final layer of the first object 2A is completed, thereby completing the first object 2A. Subsequently, the second object 2B is formed.

[0061] 7 , the modeling control unit 136 lowers the platform 12 using the elevation control unit 131, causing a portion of the first object 2A held on the platform 12 to sink into the release material 3, and positions the modeling target surface of the second object 2B of the first object 2A at a position that coincides with the interface 3A of the release material 3. Furthermore, the modeling control unit 136 controls the operation of the resin supply control unit 133 to supply or discharge the photocurable resin 1 based on the detection result of the second liquid level sensor 64, and adjusts the liquid level of the photocurable resin 1 to a predetermined thickness t relative to the height position of the interface 3A. As a result, a photocurable resin layer adjusted to the predetermined thickness t is formed on the modeling target surface of the second object 2B of the first object 2A.

[0062] Next, the modeling control unit 136 calculates an irradiation pattern that indicates the cross-sectional shape of the target second object 2B at a predetermined height, using the irradiation control unit 132, based on the three-dimensional shape data of this second object 2B, and irradiates the photocurable resin layer with light L that corresponds to the cross-sectional shape of a layer (e.g., the first layer) at the target height through the light-transmitting plate 14. This light L passes through the first object 2A, and the photocurable resin layer is cured to have the same cross-sectional shape as the first layer. Therefore, as shown in FIG. 7, a cured layer with a predetermined thickness t is formed on the modeling target surface of the first object 2A.

[0063] 8 and 9, the formation control unit 136 repeats the above-described procedure until the formation of the last layer of the second object 2B is completed, thereby completing the second object 2B (object 2). With this configuration, even if a part of the object 2 protrudes toward the platform 12, as in the case of the second object 2B, and a gap is formed between this protruding part and the object 2 (first object 2A) on the platform 12 side, it is not necessary to form a support part corresponding to this gap part together with the second object 2B and then remove this support part later, as in the conventional method. This makes it possible to simplify the formation process.

[0064] According to the second embodiment, the optical shaping device 100 includes a modeling tank 11 that stores a photocurable resin 1 and a liquid release material 3 that has a specific gravity greater than that of the photocurable resin 1 and that undergoes phase separation from the photocurable resin 1, and a platform 12 that can rise and fall relative to an interface 3A between the release material 3 and the photocurable resin 1. The optical shaping device 100 irradiates light L through the release material 3 onto the interface 3A with the release material 3, adjusting the thickness t of the photocurable resin 1, and sequentially stacks cured layers of the photocurable resin 1 to form a shaped object 2. and a step of lowering the platform 12 relative to the interface 3A to sink at least a portion of the first object 2A into the release material 3, and then, while further lowering the platform 12 relative to the interface 3A, integrally forming a second object 2B by irradiating light L with the first object 2A and laminating cured layers successively upward at a position higher than the bottom surface of the first object 2A. With this configuration, even if a portion of the object 2 is higher than the bottom surface of the first object 2A and a gap is formed between this portion and the object 2 (first object 2A) on the platform 12 side, it is not necessary to form a support portion corresponding to this gap and then remove this support portion later, as in the conventional method. This makes it possible to simplify the modeling process.

[0065] Furthermore, since the formation control unit 136 forms the second object 2B from the formation target surface of the first object 2A located on the platform 12 side toward the platform 12, even if a part of the object 2 protrudes toward the platform 12 as in the case of the second object 2B and a gap is formed between this protruding part and the object 2 (first object 2A) on the platform 12 side, it is not necessary to form a support part corresponding to this gap part together with the first object 2A and then remove this support part later, as in the conventional method. This makes it possible to simplify the formation process.

[0066] In the second embodiment, the procedure for forming the object 2 having a shape in which a part of the object protrudes toward the platform 12 has been described, but the present invention is not limited to this. For example, as shown in Fig. 10, the formation control unit 136 may be configured to form the second object 2B integrally with a surface of the first object 2A along the height direction. With this configuration, for example, the shape of the object can be easily changed during formation.

[0067] In the second embodiment, the first object 2A and the second object 2B are formed using the same photocurable resin 1. However, the first object 2A and the second object 2B may be formed using different photocurable resins. Specifically, after the step of forming the first object 2A, the formation control unit 136 executes a step of replacing the photocurable resin 1 corresponding to the first object 2A with a different type of photocurable resin, and the second object 2B is formed using this different photocurable resin. This configuration increases the variety of the object 2 by using photocurable resins that are cured with light of different wavelengths. Furthermore, selecting wavelengths that are less absorbed by the first object 2A as the different wavelengths can solve the problem of the amount of transmitted light varying depending on the thickness of the first object 2A.

[0068] The present invention has been described above with reference to the optical shaping apparatuses 10, 100 and control devices 30, 130. However, the present invention may be embodied in various different forms other than the above-described embodiments. Furthermore, the components of the illustrated optical shaping apparatuses and control devices are conceptual functional units and do not necessarily have to be physically configured as shown. In other words, the specific form of each device is not limited to the illustrated ones, and all or part of each device may be functionally or physically distributed or integrated in any unit depending on the processing load and usage status of each device.

[0069] The configuration of the control devices 30 and 130 is realized, for example, as software, by a program loaded into memory. In the above embodiment, the functional blocks are described as being realized by the cooperation of these hardware and software. In other words, these functional blocks can be realized in various forms, using only hardware, only software, or a combination of both. [Explanation of symbols]

[0070] 1 Photocurable resin 2 Sculptures 2A 1st model 2B 2nd model 3. Release material 3A Interface 10, 100 stereolithography equipment 11 Modeling tank 12 Platform 14 Light-transmitting plate 14A Top 20 Light irradiation unit 30, 130 Control device (photolithography control device) 31, 131 Lift control section 32, 132 Irradiation control unit 33, 133 Resin supply control unit 34, 134 Data storage unit 35 Definition judgment section 36, 135 Interface height control section 37 Thickness adjustment section 40 Interface height position adjustment mechanism 41 Interface Sensor 43 Pressing section 50, 60 Resin supply mechanism 51 Liquid level sensor 53 Resin supply pump 61 First liquid level sensor 63 Resin supply and discharge pump 64 Second liquid level sensor 136 Modeling Control Unit

Claims

1. a modeling tank having a light transmitting portion on a bottom surface thereof, the modeling tank storing a photocurable resin and a liquid release material having a specific gravity greater than that of the photocurable resin and capable of undergoing phase separation with the photocurable resin; a light irradiation unit that irradiates light through the light transmission unit to cure the photocurable resin adjusted to a predetermined thickness; a platform facing the interface between the release material and the photocurable resin and capable of moving up and down relative to the interface; an interface height position adjustment mechanism that adjusts the height position of the interface according to a change in the amount of the release material stored in the modeling tank; A photolithography apparatus comprising:

2. 2. The optical shaping apparatus according to claim 1, wherein the light transmitting portion has a curved surface on the side facing the release material, the curved surface having a predetermined optical effect.

3. the release material has a property that the amount of light transmitted through the release material varies depending on the height position of the interface, a control device that determines a level of definition of a cross-sectional shape at a height position to be formed, based on design image data that defines a cross-sectional shape at each predetermined height position of an object to be formed by the irradiation of light, The optical shaping apparatus according to claim 1 or 2, wherein the interface height position adjusting mechanism adjusts the height position of the interface in accordance with the determined fineness.

4. 4. The optical shaping device according to claim 3, wherein the interface height position adjustment mechanism adjusts the height position of the interface to a position higher than a predetermined reference height when the resolution is determined to be high, and adjusts the height position of the interface to a position lower than the reference height when the resolution is determined to be low.

5. 4. The optical shaping apparatus of claim 3, wherein the platform adjusts the thickness of the photocurable resin to a value thinner than a predetermined reference range when the resolution is determined to be high, and adjusts the thickness to a value thicker than the reference range when the resolution is determined to be low.

Images