JP2008238651A - Optical shaping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical shaping method which enables an optically shaped article to be efficiently formed by changing a projection region in accordance with the resolution the optically shaped article to be shaped. <P>SOLUTION: In the optical shaping method, an optically curable composition solution is irradiated selectively with light to form cured layers, and the cured layers are stacked in turn to form a microscopic, optically-shaped article. In a part wherein the microscopic, optically-shaped article is shaped in high resolution and in the other part, the projection magnification is changed, and the light-irradiation is carried out. Specifically, when light reflected by a digital mirror device 2 is condensed by a condensing lens 3 to make an optically curable composition on a shaping table 4 be irradiated with the condensed light to form the optically shaped article, the magnification of the condensing lens 3 in the other part is made smaller than that in a part which requires the high resolution, so that an area to irradiate the other part at a time is enlarged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical modeling method in which a photocurable composition liquid is selectively irradiated with light to form a cured layer, and the cured layer is sequentially stacked to form a micro-stereolithic object, and in particular, the projection region is improved. On how to do.

  2. Description of the Related Art In recent years, various electronic devices and various devices represented by portable terminals and the like have been strongly demanded to be small and light and to have high performance. For this reason, there is an increasing need for miniaturization of mechanical parts such as screws, gears, motor housings, and springs used in electronic devices. In addition, the design and design configuration of machine parts such as screws and motors used in electronic devices are performed on a computer using CAD or the like. As a method of modeling a three-dimensional model based on a three-dimensional model designed on such a computer, for example, there is an optical layered modeling method (hereinafter referred to as an optical modeling method). Below, an example of the conventional optical modeling method is shown.

  In a conventional stereolithography method, a three-dimensional model to be modeled is modeled based on cross-sectional group data obtained by parallel slicing into a plurality of layers. Usually, first, light is applied to the liquid surface of the photocurable composition in a region corresponding to the lowermost section. Thereby, the photocurable composition of the liquid surface part irradiated with light hardens | cures, and the cured resin layer of the one-step surface of a three-dimensional model is modeled. Next, an uncured photocurable composition having a predetermined thickness is coated on the surface of the cured resin layer. At this time, only a predetermined thickness of the cured resin layer is submerged in the photocurable composition. Then, the surface coated with the photocurable composition is irradiated with a laser beam along a predetermined pattern to cure the coat layer portion. The cured coat layer portion is laminated and integrated with the cured resin layer formed on the lower side. And the light irradiation and the coating of a photocurable composition are performed to the cross section adjacent to the shape | molded cross section. By repeating this, a desired three-dimensional model is formed (see Patent Documents 1 and 2).

Further, when a stereo model having a desired shape is to be formed by an optical modeling method, there is a method in which batch exposure is repeatedly performed for each predetermined region (hereinafter referred to as “projection region”). In this method, for example, light reflected by a digital mirror device is condensed by a condenser lens and irradiated onto a projection area. In this technique, for example, Patent Document 3 discloses a method for improving problems such as peeling and cracking at the boundary portion of the projection area. This projection area is also restricted by the resolution of the solid model to be formed. Specifically, when high resolution is required, a high-magnification condensing lens is used, and the projection area becomes small. Moreover, when modeling one stereolithography object, the stereolithography object was modeled by selecting the condensing lens adapted to the required high resolution part.
JP 56-144478 A JP-A-62-35966 JP 2006-272916 A

  However, when a condensing lens adapted to high resolution is used, the projection area becomes small, so that the number of times of movement of the table on which the optically shaped object is placed increases, resulting in a problem that the modeling time becomes long. Further, it is preferable that the boundary portion of the projection area is small in order to suppress the occurrence of a problem.

  This invention is made | formed in view of such a situation, and provides the optical modeling method which forms an optical modeling thing efficiently by changing a projection area | region according to the resolution of the optical modeling thing to model. For the purpose.

  One aspect of the optical modeling method according to the present invention is an optical modeling method in which a photocurable composition liquid is selectively irradiated with light to form a cured layer, and the cured layer is sequentially stacked to form a micro-stereolithic object. And the projection magnification is changed and light is irradiated between the part for modeling the micro stereolithography object with high resolution and the other part. The projection magnification can be changed using, for example, objective lenses having different magnifications. Furthermore, it is preferable to adjust the focal length after exchanging the objective lenses having different magnifications.

  ADVANTAGE OF THE INVENTION According to this invention, in the optical modeling method, the optical modeling method which forms an optical modeling thing efficiently can be provided by changing a projection area | region according to the resolution of the optical modeling thing to model.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, components having the same configuration or function and corresponding parts are denoted by the same reference numerals and description thereof is omitted.

First, the apparatus used for the optical modeling method according to the present invention will be described.
FIG. 1 is a diagram illustrating a configuration example of an optical modeling apparatus used in the optical modeling method according to the present invention. As illustrated in FIG. 1, the optical modeling apparatus 100 includes a light source 1, a digital mirror device (DMD) 2, a condenser lens 3, a modeling table 4, a dispenser 5, a recoater 6, a control unit 7, and a storage unit 8. In FIG. 1, the optical modeling apparatus 100 shows a state where the photocurable composition 9 is supplied onto the modeling table 4 and the photocurable resin 10 is formed.

  The light source 1 generates light for curing the photocurable composition 9 supplied on the modeling table 4. For example, a laser diode (LD) or an ultraviolet (UV) lamp that generates 405 nm laser light is used. The type of the light source 1 is selected according to the curing wavelength of the photocurable composition 9, and the optical modeling method of the present invention does not limit the type of the light source 1.

The digital mirror device (DMD) 2 is a device developed by Texas Instruments, and hundreds of thousands to millions of micromirrors independently moving on a complementary metal oxide semiconductor (CMOS) semiconductor, for example, 48 10,000 to 1.31 million pieces are laid. Such a micromirror can be tilted by about ± 10 degrees, for example, about ± 12 degrees about the diagonal line by an electrostatic field effect. The micromirror has a square shape in which the length of one side of the pitch of each micromirror is about 10 μm, for example, 13.68 μm. The interval between adjacent micromirrors is, for example, 1 μm. The entire DMD 2 used in the present embodiment has a quadrilateral shape of 40.8 × 31.8 mm (of which the mirror portion has a quadrangular shape of 14.0 × 10.5 mm). Is composed of 786,432 micromirrors having a length of 13.68 μm.
The DMD 2 reflects the laser beam emitted from the light source 1 by the individual micromirrors, and only the laser beam reflected by the micromirrors controlled by the control unit 7 at a predetermined angle passes through the condenser lens 3. 4 is irradiated to the photocurable composition 9 supplied on the surface. A region of the photocurable composition 9 to which the laser beam reflected by the DMD 2 is irradiated at once through the condenser lens 3 is referred to as a projection region. After the exposure of one projection area, the modeling table 4 is moved and the adjacent projection area is exposed. By repeating this, the batch exposure with the projection area as a unit is repeatedly executed.

  The condenser lens 3 guides the laser beam reflected by the DMD 2 onto the photocurable composition 9 to form a projection region. The condenser lens 3 may be a condenser lens 3 using a convex lens or a concave lens. If a concave lens is used, a projection area larger than the actual size of the DSM can be obtained. For example, the condensing lens 3 according to this embodiment reduces incident light by about 15 times and condenses it on the photocurable composition 9. In the present embodiment, a case where an objective lens is used as an example of the lens 3 will be described.

  The modeling table 4 is a flat table on which the cured resin 10 obtained by curing the photocurable composition 9 is sequentially deposited and placed. The modeling table 4 can be moved horizontally and vertically by a driving mechanism (not shown), that is, a moving mechanism. With this drive mechanism, stereolithography can be performed over a desired range.

The dispenser 5 accommodates the photocurable composition 9 and supplies a predetermined amount of the photocurable composition 9 to a predetermined position.
The recoater 6 includes, for example, a blade mechanism and a moving mechanism, and uniformly applies the photocurable composition 9.

  The control unit 7 controls the light source 1, DMD 2, modeling table 4, dispenser 5, and recoater 6 according to the control data. The control unit 7 can typically be configured by installing a predetermined program in a computer. A typical computer configuration includes a central processing unit (CPU) and memory. The CPU and the memory are connected to an external storage device such as a hard disk device as an auxiliary storage device via a bus. This external storage device functions as the storage unit 8 of the control unit 7. A storage medium drive device such as a flexible disk device, a hard disk device, or a CD-ROM (Compact Disk Read Only Memory) drive is connected to the bus via various controllers. A portable storage medium such as a flexible disk is inserted into a storage medium driving apparatus such as a flexible disk apparatus. The storage medium can store a predetermined computer program for executing the present embodiment by giving instructions to the CPU in cooperation with the operating system.

  The storage unit 8 mainly stores modeling data of a cross-sectional group obtained by slicing a three-dimensional model to be modeled into a plurality of layers. Based on the modeling data stored in the storage unit 8, the control unit 7 mainly controls the angle control of each micromirror in the DMD 2 and the movement of the modeling table 4 (that is, the position of the laser beam irradiation range with respect to the three-dimensional model). Execute the modeling of the three-dimensional model.

  The computer program is executed by being loaded into a memory. The computer program can be compressed or divided into a plurality of parts and stored in a storage medium. In addition, user interface hardware can be provided. Examples of the user interface hardware include a pointing device for inputting such as a mouse, a keyboard, or a display for presenting visual data to the user.

For the photocurable composition 9, a resin that is cured by visible light and light outside the visible light region is used. Specifically, an epoxy resin or an acrylic resin can be used. For example, an acrylic resin corresponding to 405 nm having a curing depth of 15 μm or more (500 mJ / cm ² ) and a viscosity of 1500 to 2500 Pa · s (25 ° C.) can be used.

  Next, operation | movement of the optical modeling method which uses the optical modeling apparatus 100 concerning this embodiment is demonstrated. First, the uncured photocurable composition 9 is accommodated in the dispenser 5. The modeling table 4 is in the initial position. The dispenser 5 supplies the stored photocurable composition 9 on the modeling table 4 by a predetermined amount. The recoater 6 sweeps the photocurable composition 9 so as to stretch and forms a coat layer for one layer to be cured.

The laser beam emitted from the light source 1 enters the DMD 2. The DMD 2 is controlled by the control unit 7 and adjusts the angle of a part of the micromirrors corresponding to the portion where the photocurable composition 9 is irradiated with the laser beam. Thereby, the laser beam reflected from a part of the micromirrors is irradiated to the photocurable composition 9 through the condenser lens 3, and the laser beam reflected from the other micromirrors is irradiated to the photocurable composition 9. Not. The photocurable composition 9 is irradiated with a laser beam for 0.4 seconds, for example. At this time, the projection area on the photocurable composition 9 is, for example, about 1.3 × 1.8 mm, and can be reduced to about 0.6 × 0.9 mm. The area of the projection region is usually desirably 100 mm ² or less. For this reason, when forming a three-dimensional model larger than the size of one projection area, it is necessary to move the irradiation position of the laser beam for irradiation. For example, assuming that the maximum size (X × Y) of stereolithography is used, this is divided into a plurality of projection regions (x × y), and each is irradiated with a laser beam one shot at a time. The maximum size of stereolithography is, for example, X = 150 mm, Y = 150 mm, and the height is 50 mm. The size of the projection area is, for example, x = 1.8 mm and y = 1.3 mm. Thus, by irradiating a laser beam while scanning a projection area, the photocurable composition 9 hardens | cures and the 1st cured resin layer is formed. The stacking pitch for one layer, that is, the thickness of one layer of the cured resin layer is, for example, 5 to 10 μm.

  Subsequently, a second layer of a three-dimensional model having a desired shape is simultaneously formed in the same process. Specifically, the photocurable composition 9 supplied from the dispenser 5 is applied to the outside of the cured resin layer formed as the first layer so as to be stretched beyond the three-dimensional model by the recoater 6. Then, a second cured resin layer is formed on the first cured resin layer by irradiating with a laser beam. In the same manner, the third and subsequent cured resin layers are sequentially deposited. Then, when the deposition of the final layer is completed, the stereolithography object formed on the modeling table 4 is taken out. The above is the description of the operation of the optical modeling method.

  Next, the projection area and resolution when forming a modeled object will be described. In order to obtain a high resolution when modeling an optical model, a high-magnification condensing lens 3 is used. For this reason, the area of the projection area which irradiates light becomes small. Therefore, when irradiating the same area, when modeling a high-resolution optical modeling object, the number of times of irradiation and the number of times of moving the modeling table 4 increase compared to modeling a low-resolution optical modeling object. As described above, the optical modeling object requiring high resolution has a long modeling time. In the optical modeling apparatus 100 shown in FIG. 1, a physical lens is fixed and used as the condensing lens 3 when modeling one optical modeling object. Therefore, a physical lens is selected in accordance with a portion having a high required resolution in an optically shaped object.

  Therefore, in the present embodiment, the projection magnification is increased when forming a portion that requires high resolution, and the projection magnification is decreased when forming other portions that do not require high resolution. That is, the magnification of the physical lens used for the other part is reduced as compared with the objective lens used for the part requiring high resolution. As a result, it is possible to enlarge the projection area irradiated at one time in other portions. Thereby, it becomes possible to reduce the frequency | count of irradiation.

  In the stereolithography apparatus 100 shown in FIG. 1, the resolution is determined by the size of each micromirror of the DMD 2 and the condenser lens 3 (here, a physical lens). The size of each DMD micromirror cannot be changed. For this reason, the resolution is changed by changing the physical lens. Specifically, the objective lens having a different magnification is used, and the resolution is changed by exchanging the physical lens. In addition, when the objective lens is replaced, the focal length changes, so it is necessary to adjust the focus. For this reason, as a mechanism for adjusting the focus, for example, a reference for focus adjustment is provided in addition to the modeling region. When the objective lens is replaced, the height of the objective lens is adjusted using the focus adjustment reference. Thereby, the focus adjustment of the curable composition surface and the objective lens can be performed.

  However, since the projection magnification increases and the light collection magnification also increases, the amount of light per unit area increases. For this reason, since the irradiation time per time can be shortened, the increase in the area irradiated at one time and the reduction in the irradiation time to the whole molded article do not necessarily have a proportional relationship.

  As described above, according to a preferred embodiment of the present invention, in the optical stereolithography, in particular, the micro stereolithography that forms the stereolithography using DMD, the projection magnification is changed according to the resolution of the stereolithography to be modeled. By doing so, the projection area irradiated at once can be changed. Thereby, since the frequency | count of moving the position to irradiate can be reduced, the modeling time which forms a molded article can be shortened. In addition, it is possible to suppress problems that occur at the boundary of the projection area. In this way, it is possible to improve the efficiency of modeling the optical modeling object.

  In addition, this invention is not limited to embodiment shown above. Within the scope of the present invention, it is possible to change, add, or convert each element of the above-described embodiment to a content that can be easily considered by those skilled in the art.

It is a figure which shows the structural example of the optical modeling apparatus used for the optical modeling method which concerns on this invention.

Explanation of symbols

1 Light source 2 DMD
DESCRIPTION OF SYMBOLS 3 Condensing lens 4 Modeling table 5 Dispenser 6 Recoater 7 Control part 8 Memory | storage part 9 Photocurable composition 10 Photocurable resin 100 Optical modeling apparatus

Claims (3)

In a stereolithography method of forming a three-dimensional model by irradiating light on a coating film of a photocurable composition with a projection area of 100 mm ² or less as a unit to form a cured resin layer and sequentially laminating the cured resin layer. There,
An optical modeling method of irradiating light by changing a projection magnification between a part for modeling the three-dimensional modeled object with high resolution and other parts.   The stereolithography method according to claim 1, wherein the projection magnification is changed by using objective lenses having different magnifications.   3. The stereolithography method according to claim 2, wherein the focal length is adjusted after the objective lens having a different magnification is exchanged.

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