JPWO2006035739A1 - Stereolithography apparatus and stereolithography method - Google Patents

Abstract

By obtaining a photo-cured product having a desired thickness over the entire area of each photo-cured layer, a high-quality and complicated three-dimensional model is rapidly manufactured. The light in the light irradiation region irradiated with light from the light irradiation device (1-4) is irradiated on the surface of the photocurable resin layer (5) through the mask (3) having a predetermined pattern. An apparatus and method for manufacturing a three-dimensional structure by photocuring a curable resin layer, wherein a mask (3) is synchronized with the movement while moving the light irradiation device (1-4) in at least two directions. ) Change the above mask pattern. At this time, by controlling the exposure amount of the light irradiated from the light irradiation device (1-4) to the light irradiation region, the film thickness of the photocuring layer (6) to be photocured in the light irradiation region is set to a desired value. Make the film thickness.

Description

  The present invention relates to an optical modeling apparatus and an optical modeling method for optically manufacturing a three-dimensional model by irradiating a photocurable resin composition with light and photocuring it.

  In recent years, an optical modeling apparatus that manufactures a three-dimensional model by curing a photocurable resin based on data input to a three-dimensional CAD has been put into practical use. This stereolithography technology is a model for verifying the appearance design in the middle of design, a model for checking the functionality of parts, a resin mold for producing molds, and a base model for producing molds. It attracts attention because it can easily form complex three-dimensional objects such as.

  In manufacturing a modeled object with an optical modeling apparatus, a method using a modeling bath is widely used. As the procedure, a liquid photocurable resin composition is put in the modeling bath and a desired pattern is obtained on the liquid surface. A spot-shaped laser beam controlled by a computer (for example, an ultraviolet laser beam) is selectively irradiated and photocured to a predetermined thickness to form a photocured layer, and the photocured layer is placed in the modeling bath. Then, the photocurable resin liquid in the modeling bath is caused to flow onto the photocured layer to form a photocurable resin liquid layer, and a spot-like ultraviolet laser beam is formed on the photocurable resin liquid layer. Is repeated until a three-dimensional object having a predetermined shape and size is obtained.

  In the case of the above-described conventional method using a spot-like ultraviolet laser beam, a planar photocured pattern is formed by moving the spot-shaped laser beam while irradiating the surface of the photocurable resin composition. Since it is a so-called stippling method, there is a problem that it takes a long time for modeling and the productivity is low. In addition, laser devices such as ultraviolet laser devices used as light sources are extremely expensive, making this type of optical modeling device expensive.

  Therefore, conventionally, a liquid crystal shutter (liquid crystal mask) that selectively transmits or blocks light is arranged so as to be able to run parallel to the liquid surface of the photocurable resin, and a plurality of liquid crystal shutters have a running range. Proposing a stereolithography apparatus that divides the liquid crystal shutter into each of the divided strike ranges and exposes each strike range to form a photocured layer having a predetermined cross-sectional pattern for one layer. (For example, refer to Patent Document 1).

When manufacturing a three-dimensional molded article using laser light, the photocuring depth (thickness) of each photocured layer is the product of the intensity (I) of the laser light to be irradiated to a predetermined region and the irradiation time (t), That is, it can be adjusted by controlling the laser beam irradiation exposure amount (Ixt). Here, the irradiation time is inversely proportional to the scanning speed of the laser beam. Specifically, when the scanning speed of the laser beam is constant, the film thickness of the irradiated region is controlled by modulating the intensity of the laser beam, or when the laser beam intensity is constant, By changing the scanning speed, the film thickness of the irradiation region is controlled. In order to make the exposure amount of the laser beam being scanned constant over the entire scanning region, it is necessary to control the laser device so that the intensity of the laser beam and the scanning speed of the laser beam satisfy a predetermined relationship. (For example, refer to Patent Document 2). In scanning with laser light, for example, at the scanning start position of each scanning line, the scanning speed of the laser light is zero (that is, the exposure amount is maximum), but is gradually accelerated as scanning in the traveling direction. (In other words, the exposure amount decreases), the exposure amount becomes constant (scanning exposure amount) when a constant speed (scanning speed) is reached, and the laser beam gradually decelerates near the scanning end position of each scanning line. (Ie, the exposure amount increases), and the exposure amount is maximized at the scanning end position. Therefore, in the scanning of the laser light along each scanning line, in the scanning region corresponding to each scanning line, the exposure amount becomes maximum at the scanning start position and the scanning end position, and the scanning speed is constant from these regions (exposure amount). The amount of exposure gradually decreases until the scanning speed is constant, where is constant. That is, when the intensity of the laser beam is constant, even if the scanning speed of the laser beam is set to be constant, the exposure amount in each scanning region becomes non-uniform and a constant film thickness cannot be obtained. Therefore, in the region from the scanning start (end) position to the region where the scanning speed is constant (hereinafter referred to as the scanning speed fluctuation region), the laser light intensity is made variable in accordance with the fluctuation of the scanning speed, so that the entire exposure area is covered. Thus, the exposure amount can be made constant. Specifically, during the scanning speed fluctuation region period, the laser generator is digitally or analogally modulated so that the exposure amount in this region is the same as the exposure amount in the constant scanning speed region. .
JP-A-8-112863 JP-A-6-61847

  As described above, in order to control the film thickness of the photocured layer using laser light, a control circuit for controlling the intensity of the laser light corresponding to the scanning speed is required. It was priced. In addition, when controlling the film thickness by controlling the scanning speed of the laser beam, the scanning speed by the laser beam is extremely fast, so that the scanning speed control itself is complicated, and it is difficult to perform accurate control itself. On the other hand, in the optical modeling apparatus having the exposure mechanism disclosed in Patent Document 1, nothing is disclosed regarding the film thickness control of the photocured layer, and for example, a photocured resin having a plurality of different photosensitivities is used. It is possible to deal with the control of the exposure amount when performing stereolithography, or the control of the exposure amount when forming a plurality of portions having different film thicknesses (photocuring depths) in a certain photocured layer. There was a problem that I could not.

  The present invention has been made in view of the above-described circumstances, and is capable of freely adjusting the thickness (photocuring depth) of a photocured product that can be formed in each photocured layer. It aims at providing the optical modeling apparatus and optical modeling method which can manufacture a three-dimensional molded item.

In order to achieve the above object, the present invention forms an exposure image by irradiating the surface of a photocurable resin layer with light from a light irradiation device through a mask having a predetermined pattern, and the exposure image is irradiated with the exposure image. The step of photocuring the photocurable resin layer in the irradiated region is repeated until one photocured layer is formed, and a new uncured resin layer is formed on the surface of the photocured layer. In the optical modeling apparatus for forming a three-dimensional model by repeating the process of irradiating the uncured resin layer with light through the mask to form a photocured layer,
Exposure image moving means for moving the exposure image formed on the surface of the photocurable resin layer along the surface of the photocurable resin layer;
Mask pattern variable means for changing the mask pattern on the mask in synchronization with the movement of the exposure image;
When moving the exposure image by the exposure image moving means, by changing the exposure amount of the exposure image irradiated to the light irradiation region, the film thickness of the photocured layer that is photocured in the light irradiation region can be reduced. And a control means for controlling.

  In the optical modeling apparatus, the exposure image moving means includes moving means for moving the light irradiation apparatus, and the mask pattern changing means is arranged on the mask in synchronization with the movement of the light irradiation apparatus by the moving means. The mask pattern is changed, and the control unit further controls the moving speed of the light irradiation device by the moving unit to change the exposure amount of the exposure image and photocures in the light irradiation region. The film thickness of the layer is controlled.

  In the optical modeling apparatus, the control means includes at least a light amount irradiated to the light irradiation region, a sensitivity to light curing of a photocurable resin forming a photocuring layer, and the light irradiation region in the moving direction. The moving speed is calculated based on the length of the light, and the light irradiation device is moved at the calculated moving speed via the moving means.

  In the optical modeling apparatus, the moving unit moves the light irradiation apparatus in at least two directions orthogonal to each other.

In the optical modeling apparatus, the shape of the light irradiation region is a rectangular shape having a long side length L and a short side length S, and the longitudinal direction and the short direction of the rectangular light irradiation region. Are parallel to the two movement directions of the light irradiation device, respectively, the movement speed of the light irradiation device in the longitudinal direction is VL, and the movement speed of the light irradiation device in the short direction is VS. Then, the following relational expression VL / VS = L / S
The moving speeds VL and VS are determined so that the following holds.

In the optical modeling apparatus, the shape of the light irradiation region is a rectangular shape having a long side length L and a short side length S, and the longitudinal direction and the short direction of the rectangular light irradiation region. Are parallel to the two moving directions of the light irradiation device, the moving speed of the light irradiation device in the longitudinal direction is VL, and the moving speed of the light irradiation device in the short direction is VS. , E (mJ / cm ² ) represents the amount of light irradiated to the light irradiation region, and Et (mJ / cm ² ) represents the amount of light necessary to cure the photocurable resin to a thickness t (mm). The moving speeds VL and VS in the longitudinal direction and the lateral direction of the light irradiation device for obtaining the film thickness t are respectively L · E / Et (mm / sec) and S · E / Et ( mm / sec).

  In the stereolithography apparatus, the optical sensor for measuring the light amount E of the light irradiated to the light irradiation region, the thickness t of the photocuring layer of the photocurable resin, and the photocurable resin by the thickness t Storage means storing in advance film thickness / light quantity data indicating a relationship with the light quantity Et required for curing, and the control means includes a measured value of the light quantity E from the photosensor, and the storage means. The moving speed of the light irradiation device for obtaining a desired film thickness is obtained from the stored film thickness / light quantity data.

  In the optical modeling apparatus, the mask is a planar mask in which a plurality of minute light shutters capable of shielding and transmitting light in minute dot areas are arranged in a planar shape, and a mask image is formed by these minute light shutters. The mask image is continuously changed according to the pattern to be formed in synchronization with the continuous movement with respect to the surface of the uncured resin layer.

  In the stereolithography apparatus, the mask pattern changing means controls a change speed of the mask pattern in synchronization with a moving speed of the light irradiation apparatus.

  In the optical modeling apparatus, the mask pattern changing unit changes the light transmittance of the mask pattern on the mask, thereby irradiating the light irradiation surface through the mask pattern changing unit. The exposure amount variable means for making the exposure amount variable is provided.

  The optical modeling apparatus further includes a plurality of filters having the same or different light transmittances, and the light irradiated from the light irradiation apparatus to the mask pattern variable means, or the light irradiation region from the mask pattern variable means A light-curing layer that passes through at least one of the plurality of filters to change the intensity of the light irradiated to the light-irradiated region and is photocured in the light-irradiated region. The film thickness is controlled.

  In the above-described optical modeling apparatus, the mask pattern varying means is composed of a transmissive planar drawing apparatus using liquid crystal.

  In the modeling apparatus, the mask pattern changing unit is a reflection type planar drawing apparatus using a digital micromirror device (DMD).

A light curable resin layer in a light irradiation region irradiated with the exposure image is formed by irradiating the surface of the light curable resin layer with light from a light irradiation device through a mask having a predetermined pattern. The step of photocuring is repeated until one photocured layer is formed, and a new uncured resin layer is formed on the surface of the photocured layer, and the uncured resin layer is interposed through the mask. In the optical modeling method of forming a three-dimensional model by repeating the process of forming a photocured layer by irradiating light,
An exposure image moving step of moving the exposure image formed on the photocurable resin layer surface along the photocurable resin layer surface;
A mask pattern variable step for changing the mask pattern on the mask in synchronization with the movement of the exposure image;
When moving the exposure image by the exposure image moving means, by changing the exposure amount of the exposure image irradiated to the light irradiation region, the film thickness of the photocured layer that is photocured in the light irradiation region can be reduced. And a control step for controlling.

  In the stereolithography method, the exposure image moving step includes a moving step of moving the light irradiation device in at least two directions, and the previous mask pattern changing step is performed in synchronization with the movement of the light irradiation device. The mask pattern is changed above, and the control step controls the film thickness of the photocured layer that is photocured in the light irradiation region by controlling the moving speed of the light irradiation device in the moving step. It is characterized by doing.

    In the stereolithography method, the control step includes at least the amount of light applied to the light irradiation region, the sensitivity to photocuring of the photocurable resin forming the photocuring layer, and the light irradiation region in the moving direction. A step of calculating the moving speed based on the length of the light irradiation device, wherein the light irradiation device is moved at the calculated moving speed in the moving step.

  In the stereolithography method, the mask pattern changing step includes changing the light transmittance of the mask pattern on the mask to change the exposure amount of the exposure image irradiated on the light irradiation surface. A variable amount step is provided.

  In the stereolithography method, a plurality of filters having the same or different light transmittance are disposed, and light irradiated on the light irradiation surface from the light irradiation device is allowed to pass through at least one of the plurality of filters. Thus, the method further includes the step of controlling the film thickness of the photocuring layer that is photocured in the light irradiation region by changing the intensity of the light irradiated to the light irradiation region.

  According to the present invention, since a cured product having a desired thickness (depth) can be obtained over the entire area of each photocured layer, a high-quality and complicated three-dimensional modeled object can be quickly produced.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating an external configuration of an optical modeling apparatus 100 according to the present embodiment. As shown in this figure, the optical modeling apparatus 100 is roughly divided into a modeling bath 10 filled with a liquid photocurable resin composition, and light irradiation for irradiating light on the photocurable resin composition from above. Device 20. Inside the modeling bath 10, the modeling table 11 is arranged so as to be lifted and lowered by the lifting mechanism 30.

  When manufacturing the three-dimensional modeled object, the modeling table 11 is pulled down from the liquid surface 12 of the liquid photocurable resin composition filled in the modeling bath 10 by a predetermined distance d, as shown in FIG. On the surface of the modeling table 11, a liquid photocurable resin layer corresponding to one layer of the three-dimensional modeled object, that is, an uncured photocurable resin layer (hereinafter referred to as “modeling surface 5”) is formed. . And the light irradiation apparatus 20 photocures the modeling surface 5 by irradiating light with respect to the modeling surface 5, and forms the photocuring layer corresponded to 1 layer of a three-dimensional molded item. Thereafter, the modeling table 11 is further lowered by a predetermined distance d to form a modeling surface 5 for one layer on the upper surface of the previously formed photocured layer, and the light irradiation device 20 is applied to the modeling surface 5 in the same manner as described above. By irradiating with light, a new photo-curing layer for one layer is newly formed on the photo-curing layer formed previously. Moreover, when forming each photocured layer, each photocured layer is formed in a predetermined pattern by the light irradiation device 20 irradiating the modeling surface 5 with a predetermined pattern of light, and the photocured layer is laminated. Thus, the target three-dimensional model is manufactured.

  The configuration of the light irradiation device 20 will be described in detail. As shown in FIG. 3, the light irradiation device 20 includes a light source 1, a condenser lens 2, a planar drawing mask 3, and a projection lens 4. . The light source 1 irradiates a liquid photocurable resin composition with light to form a photocured layer. For example, an ultra-high pressure mercury lamp, a metal halide lamp, or an ultraviolet lamp such as an ultraviolet fluorescent lamp is used. The light emitting end 1 a of the light source 1 is formed into a spherical shape as a whole, and the light emitted from the light emitting end 1 a is diffused with a predetermined diffusion angle and enters the condenser lens 2.

  The condensing lens 2 collects incident light and irradiates the projection lens 4 with light, and the projection lens 4 irradiates the liquid surface of the liquid photocurable resin composition with light. The curable resin composition is photocured. As shown in FIG. 3, the planar drawing mask 3 is interposed between the condenser lens 2 and the projection lens 4 so that the entire surface is irradiated with light. That is, of the light emitted from the condenser lens 2, the light that has passed through the mask image (mask pattern) of the planar drawing mask 3 is irradiated onto the modeling surface 5, and the portion (so-called exposure surface) is photocured. A photocured layer (hereinafter referred to as “exposure image”) 6 having a pattern corresponding to the mask image is formed on the modeling surface 5.

  The planar drawing mask 3 will be described in detail. In the planar drawing mask 3, a plurality of minute light shutters capable of shielding and transmitting light in minute dot areas are arranged in a planar shape, and a mask image is formed by these minute light shutters. In this embodiment, the mask image of the planar drawing mask 3 is appropriately changed (changed) by using a liquid crystal type planar drawing mask for the planar drawing mask 3 in this embodiment. The exposure image 6 having a desired pattern is obtained. As the planar drawing mask 3, for example, a TFT-type VGA (640 × 480 pixels) liquid crystal manufactured by Casio Co., Ltd. can be used.

  Here, in the present embodiment, as shown in FIG. 3, instead of forming a single layer of photocured layer at a time by performing batch exposure on the entire modeling surface 5 with the planar drawing mask 3 fixed. As the planar drawing mask 3, the planar drawing mask 3 having a width that is smaller than the entire width of the target photocured layer or the entire width of the modeling surface 5 is used, and the light irradiation position is continuously moved in the modeling surface 5. Thus, the exposure images 6 are sequentially formed to form a single layer of photocured layer (in FIG. 3, the planar drawing mask 3 having a width about half the width of the modeling surface 5 is used. Illustrate the case).

  FIG. 4 is a block diagram for explaining a movement control unit that performs a continuous movement operation of the light irradiation device. Hereinafter, the continuous movement control of the light irradiation device 20 will be described with reference to FIGS. 1 and 4. The optical modeling apparatus 100 includes an X-axis guide rail 40 and a Y-axis guide rail 41 that are disposed above the modeling bath 10 and move the light irradiation apparatus 20 to two axes of the XY axes. Yes. A support plate 42 that supports the light irradiation device 20 is movably connected to the guide rails 40 and 41. The support plate 42 is connected to an X-axis pulse motor 43 and a Y-axis pulse motor 44 that are feedback-controlled by a computer 50 via a motor drive circuit 55 shown in FIG. By driving 44, the light irradiation device 20 moves together with the support plate 42 along the XY axis, that is, parallel to the modeling surface 5.

  On the other hand, in synchronism with the continuous movement of the light irradiation device 20, the mask image data is output from the computer 50 to the planar drawing mask 3 so as to continuously change in a moving image manner. Specifically, the computer 50 stores a pattern image to be formed in advance in a storage device (for example, a hard disk device or the like) for each photocured layer of the three-dimensional structure, and the X-axis pulse motor 43 and the Y-axis pulse. As the light irradiation device 20 is continuously moved by driving the motor 44, a mask image corresponding to the light irradiation position is sequentially output to the planar drawing mask 3, and the mask image of the planar drawing mask 3 is output. To change the video. Thereby, the exposure image 6 which has a predetermined pattern in the modeling surface 5 is continuously formed with the continuous movement of the light irradiation apparatus 20.

  More specifically, an image pattern (mask pattern) for each cured layer including positional information regarding the cured site and the non-cured site for each photocured layer is obtained by image processing by the computer 50, and the information is obtained. Is stored in a storage device or the like. An address is assigned in advance to each movement position of the light irradiation device 20 (for example, the center of the head), and an address is also assigned on the image pattern corresponding to the address. That is, the moving space (XY plane) of the light irradiation device 20 and the image plane constituting the image pattern for each cured layer have a one-to-one relationship. Each time the light irradiation device 20 reaches each assigned address under the control of the computer 50, a rectangular area (hereinafter referred to as a rectangular area) centered on a position (address) on the image pattern corresponding to the movement position (address). The image data in the drawing window is supplied to the planar drawing mask 3 and displayed. The drawing window moves virtually on the image pattern in synchronization with the movement of the light irradiation device 20 (actually, the image in the planar drawing mask 3 corresponding to the drawing window is scrolled), and the surface corresponding to the drawing window The moving images are continuously displayed on the shape drawing mask. Such control is performed over one layer of the photocured layer.

  In the control method described above, the image display on the planar drawing mask 30 is controlled in synchronization with the movement of the light irradiation device 20, but on the contrary, the change in the image on the planar drawing mask 30 is controlled. The light irradiation device 20 may be driven and controlled in synchronization. As described above, the movement of the light irradiation device 20 and the image display of the planar drawing mask (liquid crystal) can be controlled synchronously because the light exposure speed (scanning speed) of the present embodiment is extremely low compared to the scanning by laser light. Because it can be done. The pulse motor is the most suitable motor for accurately moving the light irradiation device 20 in synchronization with the continuous change of the image (apparent movement of the image display dots). It goes without saying that the same effect can be obtained even if a drive motor such as the above is used. In the above-described embodiment, the computer 50 performs all the controls such as motor drive, liquid crystal drive, and image display. However, these controls are performed using a plurality of computers that share each function. Also good. For example, a computer 58 for image processing may be separately provided so that processing for creating an image to be displayed on the planar drawing mask is performed exclusively.

  Here, the continuous formation of the exposure image 6 will be described in more detail with reference to FIG. 5. First, as shown in FIG. 5 (1), the optical modeling apparatus 100 first applies the light irradiation position (planar drawing). The mask 3) is positioned so as to be outside (scanning start position) from the end 5a of the modeling surface 5. At this time, the entire surface light-shielding pattern such as the entire surface black is output from the computer 50 to the surface drawing mask 3 so as to block the light irradiation to the modeling bath 10. Next, as shown in (2) to (5) of FIG. 5, the light irradiation position is parallel to the modeling surface 5 in the direction of the outside (scanning stop position) of the other end 5 b of the modeling surface 5. Move continuously linearly with. At that time, the mask image by the planar drawing mask 3 continuously changes in a moving image according to the light irradiation position and the pattern to be formed, and light corresponding to the mask image is irradiated onto the modeling surface 5 to expose the exposure image. 6 are formed continuously.

  Then, as shown in FIG. 5 (5), when the light irradiation position is located outside the end portion 5b of the modeling surface 5, an exposure image 6 corresponding to the half width of the predetermined pattern to be formed is formed on the modeling surface 5. In this stage, the light irradiation position is moved to a position corresponding to the remaining half width of the modeling surface 5 ((6) in FIG. 5), and from that position to (6) to (10) in FIG. As shown, the light irradiation position is continuously moved from the end portion 5b of the modeling surface 5 to the end portion 5a side of the modeling surface 5, and the exposure image 6 is continuously formed in the same manner as described above. As a result, one layer of a photocured layer having a predetermined pattern (cross-sectional shape pattern) is formed on the modeling surface 5.

In the above description, the light irradiation position is set between the position outside the end 5a at one end of the modeling surface 5 (scanning start position) and the position outside the end 5b at the other end (scanning stop position). Although illustrated about the case where the photocuring layer for one layer is formed by reciprocating, not only this but light irradiation position in the said modeling surface 5 according to the light irradiation area (exposure area) and the area of the modeling surface 5 May be reciprocated multiple times to form a single layer of photocured layer. In the above description, the case where the exposure image 6 is sequentially formed in the modeling surface 5 by performing light irradiation in each of the forward path and the return path of the light irradiation position is not limited to this, but is not limited thereto. It is good also as a structure which performs light irradiation only by performing light irradiation only and forms the exposure image 6 sequentially. For example, in this configuration, the light irradiation position is continuously moved from the scanning start position of the modeling surface 5 to the scanning stop position to sequentially form the exposure images 6, and then the light irradiation position is moved from the scanning stop position without performing light irradiation. The exposure position is moved to the scanning start position, the light irradiation position is shifted to a position adjacent to the previously formed exposure image 6, and the exposure image 6 is successively formed again by continuously moving from the scanning start position to the scanning stop position. And this process is repeated and the photocuring layer for one layer is formed.

  As described above, the scanning start position of the light irradiation position (movement start position of the light irradiation apparatus 20) and the scanning stop position of the light irradiation position (movement stop position of the light irradiation apparatus 20) are positions outside the modeling surface 5, respectively. Thus, acceleration and deceleration are started from this position, respectively. Further, since the surface exposure scanning of the present application is extremely low (for example, 75 to 100 mm / sec) as compared with the laser beam scanning speed (for example, 1000 to 5000 mm / sec), it reaches a constant exposure speed after being accelerated. The liquid crystal shutter can also respond sufficiently without taking much time until it stops (decelerates to stop). Therefore, before the light irradiation device 20 starts moving and before entering the modeling surface 5, the light irradiation device 20 can reach a constant exposure speed, and the light irradiation intensity at the time of acceleration such as laser light scanning can be increased. There is no need to make adjustments. Similarly, since the light irradiation device 20 starts the deceleration operation when it reaches the outside of the modeling surface 5, it is not necessary to adjust the light irradiation intensity at the time of deceleration such as laser light scanning. In addition, it is extremely slow compared to the scanning speed of the laser beam, and the scanning speed can be controlled more easily and accurately when a certain exposure speed is reached. The film thickness of the film can be accurately controlled.

  Next, control of the curing depth (film thickness) of the photocurable resin layer will be described. The film thickness of the photocurable resin layer can be freely adjusted by controlling the exposure amount of the irradiated light. The exposure amount is determined by the product of the light intensity of the irradiated light and the irradiation time (reciprocal of the exposure speed). Therefore, by controlling the exposure speed with the light intensity of the irradiation light constant, or by controlling the light intensity with the exposure speed of the irradiation light constant, the cured film thickness of the photocurable resin layer can be reduced. Can be adjusted.

  First, a method for adjusting the film thickness of the photocurable resin layer by controlling the exposure speed with the light intensity kept constant will be described.

  FIG. 6 is a schematic view showing the movement control (scanning speed control) operation of the light irradiation device 20 of this embodiment. When the shape of the planar drawing mask is rectangular, the shape of the area (exposure area) EA where the light transmitted through the planar drawing mask is irradiated on the modeling surface 5 has a long side length L, The short side has a rectangular shape represented by S. Further, the moving speed of the exposure area EA in the longitudinal direction (arrow L direction) of the modeling surface 5 is VL, and the moving speed in the short direction (arrow S direction) perpendicular thereto is VS. Here, in order to simplify the explanation, it is assumed that the movement of the light irradiation device 20 is performed in parallel with the longitudinal direction or the short direction of the modeling surface 5. Further, the longitudinal direction L corresponds to the X-axis direction in FIG. 3, and the short direction S corresponds to the Y-axis direction in FIG. In FIG. 5, A1 and B1 indicate exposure regions at the scanning start positions when the light irradiation device 20 is moved in the longitudinal direction and the short direction, respectively, and A2 and B2 indicate the exposure regions 20 respectively. The exposure area at the scanning stop position when moved in the longitudinal direction and the lateral direction is shown. In any of these states, since the liquid crystal shutter is in a closed state, no light is irradiated.

  First, a case where scanning in the longitudinal direction is performed will be described. By driving the Y-axis pulse motor under the control of the computer 50, the exposure area is adjusted to a predetermined scanning start position. Further, the X-axis pulse motor is driven to accelerate the light irradiation device 20 from the scanning start position (A1) in the longitudinal direction. When the predetermined exposure speed is reached, acceleration is stopped and the light irradiation device 20 is moved in the longitudinal direction while keeping the exposure speed constant. At this time, acceleration control is performed so that the light irradiation device 20 reaches a predetermined exposure speed before the exposure area EA enters the one end 5 a of the modeling surface 5. Image information synchronized with the movement of the light irradiation device 20 is supplied to the planar drawing mask from the time when the exposure area EA enters the modeling surface 5. Thereby, the exposure image 6 corresponding to the image information is irradiated into the exposure area EA on the modeling surface 5, whereby the photocurable resin in the exposure area EA is cured corresponding to the exposure image. Become. As described above, the depth of the photocurable resin to be cured here (the film thickness of the photocured layer) is determined depending on the exposure speed (scanning speed). Therefore, the film thickness of an arbitrary photocured layer can be obtained by controlling the exposure speed at this time.

Here, E (mJ / cm ² ) is the amount of light irradiated to the surface exposure region, and the amount of light necessary to cure the photocurable resin to a thickness t (mm) (photocuring of the photocurable resin). Assuming that Et (mJ / cm ² ) depends on the sensitivity and the like, the time required to obtain a photocured layer having a thickness t can be expressed by Et / E (sec). Here, since the length of the exposure region in the longitudinal direction L is L, the exposure speed (scanning speed) VL for obtaining the film thickness t is L / (Et / E) = LE · E / Et (mm / sec). )It can be expressed as. Therefore, in order to obtain a desired film thickness in each layer or each part of each layer, the exposure speed VL obtained from the above formula is calculated, and the X-axis pulse motor is controlled so that the exposure speed becomes the calculated exposure speed. What is necessary is just to control a drive.

  Next, a case where scanning in the short direction is performed will be described. The exposure area is adjusted to a predetermined scanning start position by driving the X-axis pulse motor under the control of the computer 50. Further, the Y-axis pulse motor is driven to accelerate the light irradiation device 20 from the scanning start position (B1) in the short direction. When the predetermined exposure speed is reached, acceleration is stopped and the light irradiation device 20 is moved in the short direction while keeping the exposure speed constant. At this time, acceleration control is performed so that the light irradiation device 20 reaches a predetermined exposure speed before the exposure area EA enters one end of the modeling surface 5. Image information synchronized with the movement of the light irradiation device 20 is supplied to the planar drawing mask from the time when the exposure area EA enters the modeling surface 5. Thereby, the exposure image 6 corresponding to the image information is irradiated into the exposure area EA on the modeling surface 5, whereby the photocurable resin in the exposure area EA is cured corresponding to the exposure image. Become. As described above, the depth of the photocurable resin to be cured here (the film thickness of the photocured layer) is determined depending on the exposure speed (scanning speed). Therefore, the film thickness of an arbitrary photocured layer can be obtained by controlling the exposure speed at this time. The above operation is exactly the same as scanning in the longitudinal direction.

  In the same manner as the method for obtaining the exposure speed (scanning speed) in the longitudinal direction, the exposure area (scanning speed) VS for obtaining the film thickness t is S because the length of the exposure area in the short direction is S. / (Et / E) = S · E / Et (mm / sec). In order to obtain a desired film thickness in each layer or each part of each layer, the exposure speed VS obtained from the above formula is calculated, and the Y-axis pulse motor is driven so that the exposure speed becomes the calculated exposure speed. Control is sufficient.

  Accordingly, the ratio (VL / VS) between the exposure speed (scanning speed) VL in the longitudinal direction and the exposure speed (scanning speed) VS in the short direction is L / S. That is, it is necessary to increase the exposure speed in the longitudinal direction (lower the exposure speed in the short direction) by the amount corresponding to the ratio of the long side to the short side of the exposure region. In this case, since the exposure speeds in the longitudinal direction and the short direction are different, the display speed of the moving image on the planar drawing mask needs to be changed according to the ratio of the exposure speeds. These processes are also performed by the computer 50. On the other hand, since the light intensity (light quantity E) of the light source changes with deterioration over time, the illuminance of the light source is detected using an optical sensor or the like immediately before the modeling process or during the process. The light quantity E as a parameter may be measured in advance or in real time. The amount of light (energy) Et necessary to obtain a desired film thickness varies depending on the type of photocurable resin, that is, the photosensitivity of each photocurable resin, the ambient temperature, and the like. Are also set in advance, or set in real time during the modeling process. These data are stored in the storage device.

  As described above, in order to obtain a desired film thickness of the photocured layer using a predetermined photocurable resin, various parameters are input to the computer 50 through recording means or input means, and these parameters are set. Based on this, the exposure speeds (scanning speeds) VL and VS described above may be determined. The exposure speeds (scanning speeds) VL and VS are determined for each layer or for each part in each layer. When determined for each part in each layer, unlike scanning with laser light, the scanning speed itself is low, so the scanning speed can be variably controlled accurately and reliably even during scanning. A photocuring pattern having changes can be obtained for each layer. For example, in a photocured layer, it is possible to form a part where the film thickness changes continuously (with gradation) or changes stepwise, and the film thickness control of this embodiment makes it more complicated. A three-dimensional object having a simple shape can be created. Further, it is known that if the moving speed of the light irradiation device 20 is increased, noise due to vibrations of the moving mechanism of the light irradiation device 20 is reduced. In this case, if the movement of the light irradiation device 20 is made as high as possible, the moving speed of the exposure image formed on the photocurable resin layer is also increased, so that the exposure amount is reduced. Therefore, in order to compensate for the decrease in exposure amount, the exposure operation at the same place is repeated. The number of repeated exposures is changed as appropriate according to an increase in moving speed. For example, if the exposure speed is doubled, the exposure operation for the same area needs to be repeated twice. Instead of repeating the exposure operation, the light intensity applied to the photocurable resin layer may be increased according to the increase in the moving speed. This will be described later.

  Further, according to the present embodiment, as a mask, a plurality of minute light shutters that can shield and transmit light in minute dot areas are arranged in a planar shape, and a planar shape that forms a mask image by these minute light shutters. Since the drawing mask 3 is used, the exposure area can be increased, and, for example, compared with a so-called point drawing method in which a spot-shaped laser beam is scanned in the modeling surface 5 to form a pattern. It is possible to shorten the time required for increasing the productivity.

  In addition, according to the present embodiment, the planar drawing mask 3 is configured to continuously change the mask image according to the pattern to be formed in synchronization with the continuous movement with respect to the modeling surface 5, so that the small-sized, medium-sized High-quality three-dimensional models can be manufactured with high modeling speed and high productivity even with large three-dimensional models as well as large three-dimensional models with a high modeling system and prevention of curing unevenness. can do.

  In the above-described embodiment, the condensing lens 2 is directly irradiated with light from the light source 1. However, the present invention is not limited to this, and as shown in FIG. It is good also as a structure led to the condensing lens 2 via this. Specifically, the light transmission mechanism 60 includes a rod lens 61 that outputs light from the light source 1 in a line shape, an imaging lens 62 that diffuses the line light output from the rod lens 61, And a reflecting mirror 63 that irradiates the light diffused by the imaging lens 62 toward the condenser lens 2. As described above, the configuration in which the light from the light source 1 is transmitted to the condenser lens 2 via the light transmission mechanism 60 enables the light source 1 and the condenser lens 2 to be spaced apart from each other, and the light from the light source 1 to be disposed. There is no need to match the axis and the optical axis of the condenser lens 2, and the layout of the optical system becomes flexible.

  The optical transmission mechanism 60 is not limited to the above configuration, and an optical fiber 64 (or a ride guide) may be used as the optical transmission mechanism 60 as shown in FIG. In this case, light may be emitted from the emission end 64 a of the optical fiber 64 toward the condenser lens 2. In this way, by using a flexible material such as the optical fiber 64 for the light transmission mechanism 60, when the light irradiation position is continuously moved in the modeling surface 5, the light source 1 is fixedly disposed at a predetermined position. The transmission mechanism 60 can be continuously moved together with the condenser lens 2, the planar drawing mask 3, and the projection lens 4.

  In the above-described embodiment, the exposure speed is controlled mainly by controlling the moving speed of the light irradiation apparatus 20, but it is not necessarily limited to the control method of the moving speed of the light irradiation apparatus 20. . For example, the light irradiation device 20 may be fixed and the modeling surface 5 itself may move relative thereto. In this case, a mechanism for moving the modeling table 11 or moving the modeling bath 10 may be provided. These moving mechanisms are the same as the moving mechanisms of the light irradiation device 20 (that is, mechanisms that can move in parallel in the X and Y axis directions), and the surface drawing mask is controlled according to the movement control by these moving mechanisms. The mask pattern is controlled. In any case, the moving mechanism may take any form as long as it can control the relative moving speed of the exposure image with respect to the modeling surface 5 (photocurable resin layer).

  In the above-described embodiment, the configuration using the light transmission type liquid crystal type as the planar drawing mask 3 is exemplified. However, the configuration is not limited to this, and light shielding and light transmission in a minute dot area are possible. Further, it may be configured such that these light shielding and light transmission can be continuously performed. Further, for example, a reflection type configuration using a planar drawing mask (hereinafter referred to as “DMD type planar drawing mask” (digital micromirror device)) in which digital micromirror shutters are arranged in a plane may be employed. In this case, the formation (change) of the exposure image is performed by reflection of the digital micromirror, but the description will be made using the term “mask” as in the case of the transmissive liquid crystal type. Therefore, in the present specification, the term “mask” is not limited to a transmission type, but is applied to a reflection type configuration. As described above, when a DMD type surface drawing mask is used as the surface drawing mask 3, as shown in FIG. 9, the predetermined cross-sectional shape to be formed and the continuous movement of the DMD type surface drawing mask are made to correspond. Depending on the information stored in advance in the computer 50, light is reflected (guided) from a specific mirror shutter among a plurality of minute mirror shutters arranged in a plane shape in the direction of the projection lens 4 and the modeling surface 5. ), The mirror shutter located at a location where light should be shielded is directed in a direction in which the light is not reflected (not guided) in the direction of the projection lens 4 and the modeling surface 5, and such an operation is performed in a predetermined cross section. What is necessary is just to design it to repeat continuously (moving image-like) until the photocured resin layer which has a shape is formed.

  FIG. 10 is a cross-sectional view showing a configuration of a DMD optical system using the DMD type planar drawing mask shown in FIG. The light emitted from the light source 1 passes through the infrared filter and the condensing lens 2, and is then made uniform into the light from the light source, and is incident on the quartz rod lens 7 that forms DMD mask similar light. Further, the light from the quartz rod lens 6 becomes parallel light through the first lens 8 and the second lens group 9, is irradiated onto the DMD through the prism 10, and then converges on the projection lens 4 to be projected onto the projection lens 4. 4 is finally projected onto the modeling surface 5.

  Here, the difference in effect between the case of the transmissive planar drawing mask 3 using liquid crystal and the reflective drawing mask 3 using DMD will be described. First, in the case of the transmission type planar drawing mask 3 using liquid crystal, the transmission efficiency is about 10%, but in the case of the reflection type drawing mask 3 using DMD, the reflection efficiency is as high as about 50%. The modeling speed can be improved. When TFT liquid crystal is used as the liquid crystal, the response speed of the liquid crystal is about 60 Hz. However, when DMD is used, the response speed is about 2 kHz, and the response speed can be considerably improved. Thereby, the positioning accuracy is further improved, and the modeling accuracy itself can be improved. Specifically, it is possible to obtain an effect that a servo motor is used when the drawing head is moved and drawing positioning can be performed using a servo movement pulse (closed loop).

  Furthermore, when the TFT liquid crystal is used, the contrast is about 1: 100 to 1:10, but when the DMD is used, the contrast is 1: 1000 or more, and the contrast is improved by 10 to 100 times. Can do. Thereby, for example, in the case of liquid crystal, there was a slight amount of leaked light even in a portion that was not originally irradiated, but in the case of using DMD, there is theoretically no leaked light. The accumulated light energy of the leaked light over a long period of time causes deterioration of the resin. However, when DMD is used, such deterioration of the resin is reduced. In addition, by improving the contrast, the contour of the three-dimensional structure becomes sharper, which brings about an effect of improving the modeling accuracy. On the other hand, since the DMD itself is very compact, the optical system itself can be designed compactly. Therefore, the entire apparatus can be reduced in size, and the exposure head can be moved more smoothly. Furthermore, in the case of liquid crystal, since it is an organic substance, deterioration due to ultraviolet rays can be considered, but in the case of DMD, since no organic substance is used, deterioration due to ultraviolet rays can be minimized.

  In addition, even if it is a case where either a liquid crystal type or DMD type is used as the planar drawing mask 3, the shape is not particularly limited to the above-described embodiment, and the shape of the optical modeling object to be manufactured. Depending on the size and dimensions (particularly the cross-sectional shape and its dimensions), a suitable shape can be employed. That is, the planar drawing mask 3 may have a square or rectangular shape as shown in FIG. 3 or other shapes, for example. In the case of a square shape, the exposure speeds VL and VS in the longitudinal direction and the short direction are both equal. Furthermore, the dimensions of the planar drawing mask 3 can be appropriately sized according to the shape and dimensions (particularly the cross-sectional shape and dimensions thereof) of the optical modeling object to be manufactured. For example, as shown in FIG. 3, a planar drawing mask 3 having a width dimension smaller than the full width of the predetermined photocured cross-sectional shape pattern to be formed (full width of the modeling surface) is used. A predetermined photocured cross-sectional shape pattern having a size larger than that of the mask 3 can be manufactured.

  In the above-described embodiment, by controlling the moving speed of the light irradiation device 20, the moving speed (that is, the exposure speed) of the exposure image (the exposure area EA in FIG. 5) formed on the modeling surface 5 is changed. Thereby, the film thickness of the photocured layer was controlled. That is, the curing depth (film thickness) of the photocurable resin layer is adjusted by controlling the exposure speed. The curing depth (film thickness) of the photocurable resin layer can also be adjusted by controlling the intensity of the irradiated light while keeping the exposure speed constant. Here, the intensity adjustment (exposure amount adjustment) of the irradiated light is performed by changing the gradation of the planar drawing mask 3 and arbitrarily changing the light transmittance of the planar drawing mask 3. That is, when the light transmittance of the planar drawing mask 3 is lowered, the light intensity of the entire irradiation light that has passed through the planar drawing mask 3 is reduced. Conversely, when the light transmittance is increased, the light passes through the planar drawing mask 3. The light intensity of the whole irradiation light will increase. Thereby, since the exposure amount of the light irradiated onto the modeling surface 5 is controlled even in a state where the exposure speed is constant, the film thickness of the photocurable resin layer can be freely adjusted accordingly. Therefore, the cured film thickness of the photocurable resin layer can be freely adjusted by controlling the light transmittance of the planar drawing mask 3 without controlling the movement of the light irradiation device 20. Further, even when the exposure speed is increased for the purpose of reducing noise, by increasing the light transmittance of the planar drawing mask 3 in accordance with the increase of the exposure speed, as a result, the modeling surface 5 is irradiated. Since it is possible to compensate for the reduction in light exposure, it is not necessary to repeat the exposure operation.

  The light transmittance of the planar drawing mask 3 is controlled by the computer 50 in FIG. The computer 50 outputs a control signal for varying the light transmittance to the planar drawing mask 3 in response to the change in the moving speed of the light irradiation device 20 based on the signal to the motor drive circuit. Based on this control signal, the planar drawing mask 3 changes its light transmittance uniformly over the entire planar drawing mask 3 or locally, for example, a mask portion (light Change only in the transparent part. Further, the control of the light intensity of the irradiation light (exposure image) to the modeling surface 5 is not limited to the adjustment of the light transmittance of the planar drawing mask 3, and other methods may be used. For example, using a plurality of filters having the same or different light transmittance, the light before or after irradiation to the planar drawing mask 3 is passed through a single filter appropriately selected from the plurality of filters. Alternatively, the light intensity of the irradiated light may be adjusted by irradiating the modeling surface 5 through two or more appropriately selected filters. The filter used may be a single filter having a plurality of regions having different light transmittances. In this case, a region having a required light transmittance is selected, and the modeling surface 5 is irradiated with light through the region.

  In the above-described embodiment, the planar drawing mask 3 is configured to move parallel to the modeling surface 5, but is not necessarily limited thereto, and may be moved non-parallel to the modeling surface 5 as necessary. Also good. For example, in manufacturing a three-dimensional model, in each of the photocured layers, a shape in which a predetermined cross-sectional shape pattern to be formed becomes a continuous drawing region larger than the dimension (area) of the planar drawing mask and In the manufacture of a three-dimensional structure having a structure, the planar drawing mask 3 is continuously moved relative to the surface of the photocurable resin composition (the modeling surface 5), and a mask image of the planar drawing mask is formed. The surface of the photocurable resin composition is placed on the surface of the photocurable resin composition through the surface drawing mask 3 while continuously changing in synchronization with the movement of the surface drawing mask 3 corresponding to the cross-sectional shape pattern. By irradiating light, a photocured layer having a predetermined cross-sectional shape pattern is formed, and this is laminated to form a desired three-dimensional modeled object. Even in this case, it goes without saying that the exposure speed is corrected so as not to cause a difference in exposure time according to each scanning direction.

  Depending on the shape and structure of the three-dimensional model, a predetermined cross-sectional pattern larger than the area of the planar drawing mask 3 is formed and a cross-sectional pattern smaller than the area of the planar drawing mask 3 is formed during the molding operation. It may be necessary to form (for example, in a three-dimensional structure having a sharp corner (one) at the top of the spherical main body, the cross-sectional area (cross-sectional shape pattern) of the spherical main body portion is the planar drawing mask 3. The cross-sectional area (cross-sectional shape pattern) of the portion corresponding to the corner is smaller than the area of the planar drawing mask 3). In such a case, the formation of the main body portion having a large cross-sectional shape pattern is performed by repeating the above-described modeling operation for continuously changing the mask image of the planar drawing mask 3 over multiple layers, while the small cross-section is formed. In the corner portion having the shape pattern, the mask image of the planar drawing mask 3 is changed to a still image state without changing the moving image, and the formation of the corner portion is completed through the operation of irradiating the modeling surface with light through the mask image. By repeating the process over multiple layers, a target three-dimensional model can be manufactured.

  In the above-described embodiment, the configuration in which the number of the planar drawing masks 3 is one is illustrated. However, the configuration is not limited to this, and a configuration including a plurality (two or more) of the planar drawing masks 3 is used. It is also possible to form the exposure image 6 by continuously moving the shape drawing mask 3 simultaneously. By doing in this way, modeling speed improves further.

  In embodiment mentioned above, light is irradiated with respect to the liquid photocurable resin composition with which the modeling bathtub 10 was filled, and a photocuring layer is formed in the upper surface of the modeling table 11 arrange | positioned in the said modeling bathtub 10 concerned. And although it illustrated about the structure which laminates and forms the said photohardened layer and forms a three-dimensional molded item, it is not restricted to this, For example, a modeling table is arrange | positioned in gas atmosphere and the liquid for one layer is formed on the modeling table surface. Then, after applying a photocurable resin composition in the form of a paste, powder or thin film and irradiating light through the planar drawing mask 3 to form a photocured layer having a predetermined pattern and thickness, the photocuring Light having a predetermined pattern and thickness by applying a liquid, paste-like, powdery or thin-film photocurable resin composition for one layer to the layer surface and irradiating light under control through the planar drawing mask 3 Work to laminate the hardened layer together Performed by repeating, it may be configured to form a three-dimensional object.

  Further, in this configuration, the modeling table or the photocuring layer is faced upward, the photocurable resin composition is applied to the upper surface, and light is irradiated through the planar drawing mask 3 to sequentially form the photocuring layers. It is good also as a structure to carry out, and it arrange | positions a modeling table or a photocuring layer perpendicularly | vertically or diagonally, gives a photocurable resin layer on a modeling table surface or a photocuring layer surface, and irradiates light through the planar drawing mask 3. It is good also as composition which carries out layering formation of a photocuring layer one by one, or arranges a modeling table or a photocuring layer in the downward direction, and gives a photocurable resin layer composition to a modeling table surface or a photocuring layer surface, and is planar. It is good also as a structure which irradiates light through the drawing mask 3 and laminates | stacks a photocuring layer below sequentially. In applying the photocurable resin composition to the modeling table surface or the photocured layer surface, for example, blade coating, cast coating, roller coating, transfer coating, brush coating, spray coating, or the like can be used.

  The kind in particular of photocurable resin composition is not restrict | limited, Any of liquid, paste, powder form, thin film form, etc. which can be used for optical shaping | molding can use all. For example, the photo-curable resin composition contains one or more of acrylic compounds, polyfunctional vinyl compounds, various epoxy compounds, a photopolymerization initiator, and a sensitizer if necessary. The photocurable resin composition to be used can be used. In addition to these components, a leveling agent, a surfactant other than a phosphate ester-based surfactant, an organic polymer modifier, an organic plasticizer, and the like may be contained as necessary. Furthermore, you may contain fillers, such as a solid fine particle and a whisker, as needed. When a photocurable resin composition containing a filler is used, it is possible to improve dimensional accuracy by reducing volume shrinkage at the time of curing, improve mechanical properties and heat resistance, and the like.

  This stereolithography equipment should be used to manufacture models for precision parts, electrical / electronic parts, furniture, building structures, automotive parts, various containers, castings, molds, master molds, and processing models. It can also be used to manufacture parts for designing complex heat medium circuits, parts for analyzing heat medium behavior of complex structures, and other various 3D objects with complex shapes and structures. Can do.

It is a figure which shows the structure of the optical modeling apparatus of this invention. It is a figure which shows the structure of a modeling bathtub. It is a figure which shows the structure of a light irradiation apparatus. It is a block diagram for demonstrating the movement control part of a light irradiation apparatus. It is a principle figure for demonstrating the movement control operation | movement of a light irradiation apparatus. It is a figure for demonstrating the lamination | stacking formation procedure of a photocuring layer. It is a figure which shows the other structure of a light irradiation apparatus. It is a figure which shows the other structure of a light irradiation apparatus. It is a figure which shows the other structure of a light irradiation apparatus. It is sectional drawing of the light irradiation apparatus at the time of using the DMD optical system of FIG.

Explanation of symbols

1 Light source 3 Planar drawing mask (liquid crystal mask)
5 Modeling surface (uncured resin layer)
DESCRIPTION OF SYMBOLS 10 Modeling bathtub 11 Modeling table 43 X-axis pulse motor 44 Y-axis pulse motor 50 Computer 55 Motor drive circuit 100 Stereolithography apparatus

Claims (18)

A light curable resin layer in a light irradiation region irradiated with the exposure image is formed by irradiating the surface of the light curable resin layer with light from a light irradiation device through a mask having a predetermined pattern. The step of photocuring is repeated until one photocured layer is formed, and a new uncured resin layer is formed on the surface of the photocured layer, and the uncured resin layer is interposed through the mask. In the optical modeling apparatus that forms a three-dimensional model by repeating the process of forming a photocured layer by irradiating light,
Exposure image moving means for moving the exposure image formed on the surface of the photocurable resin layer along the surface of the photocurable resin layer;
Mask pattern variable means for changing the mask pattern on the mask in synchronization with the movement of the exposure image;
When moving the exposure image by the exposure image moving means, by changing the exposure amount of the exposure image irradiated to the light irradiation region, the film thickness of the photocured layer that is photocured in the light irradiation region can be reduced. An optical modeling apparatus comprising a control means for controlling.   The exposure image moving means includes moving means for moving the light irradiation device, and the mask pattern changing means changes the mask pattern on the mask in synchronization with the movement of the light irradiation device by the moving means. Further, the control means controls the moving speed of the light irradiation device by the moving means to vary the exposure amount of the exposure image, and controls the film thickness of the photocuring layer that is photocured in the light irradiation area. The optical modeling apparatus according to claim 1, wherein:   The control means is based on at least the amount of light irradiated to the light irradiation region, the sensitivity to photocuring of the photocurable resin forming the photocuring layer, and the length of the light irradiation region in the moving direction. The optical modeling apparatus according to claim 2, wherein the moving speed is calculated, and the light irradiation apparatus is moved at the calculated moving speed via the moving unit.   The optical modeling apparatus according to claim 3, wherein the moving unit moves the light irradiation apparatus in at least two directions orthogonal to each other. The shape of the light irradiation region is a rectangular shape having a long side length L and a short side length S, and the light irradiation region has a longitudinal direction and a short direction, respectively. When parallel to the two movement directions of the apparatus, the following relationship is assumed when the movement speed of the light irradiation apparatus in the longitudinal direction is VL and the movement speed of the light irradiation apparatus in the short direction is VS: Formula VL / VS = L / S
5. The stereolithography apparatus according to claim 4, wherein the movement speeds VL and VS are determined so that The shape of the light irradiation region is a rectangular shape having a long side of L and a short side of S, and the longitudinal direction and the short direction of the rectangular light irradiation region are respectively the light irradiation. When parallel to the two movement directions of the apparatus, the movement speed of the light irradiation apparatus in the longitudinal direction is VL, the movement speed of the light irradiation apparatus in the short direction is VS, and the light irradiation area is moved to the light irradiation area. When the amount of light to be irradiated is E (mJ / cm ² ) and the amount of light necessary to cure the photocurable resin to a thickness t (mm) is Et (mJ / cm ² ), the film The moving speeds VL and VS in the longitudinal direction and the short direction of the light irradiation device for obtaining the thickness t are represented by L · E / Et (mm / sec) and S · E / Et (mm / sec), respectively. The optical modeling apparatus according to claim 4, wherein:   An optical sensor that measures the amount of light E irradiated to the light irradiation region, a thickness t of the photocuring layer of the photocurable resin, and an amount of light necessary for photocuring the photocurable resin by the thickness t Storage means storing in advance film thickness / light quantity data indicating a relationship with Et, and the control means measures the measured value of the light quantity E from the optical sensor and the film thickness stored in the storage means. 3. The stereolithography apparatus according to claim 2, wherein a moving speed of the light irradiation device for obtaining a desired film thickness is obtained from the light amount data.   The mask is a planar mask in which a plurality of micro light shutters capable of shielding and transmitting light in a micro dot area are arranged in a plane, and a mask image is formed by these micro light shutters, and the uncured resin layer The optical modeling apparatus according to claim 1, wherein the mask image is continuously changed according to a pattern to be formed in synchronization with a continuous movement with respect to the surface of the laser beam.   The optical modeling apparatus according to claim 2, wherein the mask pattern changing unit controls a change speed of the mask pattern in synchronization with a moving speed of the light irradiation apparatus.   The mask pattern variable means can change the exposure amount of the exposure image irradiated on the light irradiation surface via the mask pattern variable means by changing the light transmittance of the mask pattern on the mask. The optical modeling apparatus according to claim 1, further comprising an exposure amount varying unit that performs the operation.   A plurality of filters having the same or different light transmittance, and light irradiated from the light irradiation device to the mask pattern variable means or light irradiated from the mask pattern variable means to the light irradiation region; By passing through at least one of the plurality of filters, the intensity of the light irradiated to the light irradiation region is variable, and the film thickness of the photocured layer that is photocured in the light irradiation region is controlled. The optical modeling apparatus according to claim 1.   2. The stereolithography apparatus according to claim 1, wherein the mask pattern changing unit includes a transmissive surface drawing apparatus using liquid crystal.   2. The stereolithography apparatus according to claim 1, wherein the mask pattern changing unit includes a reflective planar drawing apparatus using a digital micromirror device (DMD). A light curable resin layer in a light irradiation region irradiated with the exposure image is formed by irradiating the surface of the light curable resin layer with light from a light irradiation device through a mask having a predetermined pattern. The step of photocuring is repeated until one photocured layer is formed, and a new uncured resin layer is formed on the surface of the photocured layer, and the uncured resin layer is interposed through the mask. In the optical modeling method of forming a three-dimensional model by repeating the process of forming a photocured layer by irradiating light,
An exposure image moving step of moving the exposure image formed on the photocurable resin layer surface along the photocurable resin layer surface;
A mask pattern variable step for changing the mask pattern on the mask in synchronization with the movement of the exposure image;
When moving the exposure image by the exposure image moving means, by changing the exposure amount of the exposure image irradiated to the light irradiation region, the film thickness of the photocured layer that is photocured in the light irradiation region can be reduced. An optical modeling method comprising: a control step for controlling.   The exposure image moving step includes a moving step of moving the light irradiation device in at least two directions, and the previous mask pattern changing step moves the mask pattern on the mask in synchronization with the movement of the light irradiation device. Further, the control step controls the film thickness of the photocured layer that is photocured in the light irradiation region by controlling the moving speed of the light irradiation device in the moving step. The optical modeling method according to claim 12.   The control step is based on at least the amount of light irradiated to the light irradiation region, the sensitivity to photocuring of the photocurable resin forming the photocuring layer, and the length of the light irradiation region in the moving direction. The optical modeling method according to claim 9, further comprising a step of calculating the moving speed, wherein the light irradiation device is moved at the calculated moving speed in the moving step.   The mask pattern variable step includes an exposure amount variable step of changing an exposure amount of the exposure image irradiated on the light irradiation surface by changing a light transmittance of the mask pattern on the mask. The optical modeling apparatus according to claim 12, wherein: A plurality of filters having the same or different light transmittance are arranged, and the light irradiated from the light irradiation device onto the light irradiation surface is allowed to pass through at least one of the plurality of filters. The optical modeling apparatus according to claim 12, further comprising a step of controlling a film thickness of a photocuring layer that is photocured in the light irradiation region by changing the intensity of the light irradiated to the region.

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