JPH04267132A - Three dimensional object-forming device - Google Patents

Abstract

PURPOSE:To reduce the operational time for forming a three dimensional object, while the scanning of two dimensional laser beam is made unnecessary by providing a liquid-crystal spatial optical modulator, and the light source for curing light-curable material, etc., in the forming of the light-curable material by using laser beam. CONSTITUTION:The laser beam 112 outputted from a laser source 10 is made into the parallel beam expanded by a beam-expander 102 and a collimate lens 103. Said laser beam 112 is phase-modulation according to the computer- holograph recorded by a liquid-crystal optical modulator 104 in mode ECB (electric field-controlling birefringence), whereby the cross sectional image of three dimension is regenerated on the surface of a resin tank 105. The uncured resin 106 on the surface of the resin tank is cured by the radiation of laser beam. Then, while a formed object 7 is fixed onto a table 108, and the table 108 is sent downward by a z-direction-sending device 109, the uncured resin which appears successively on the surface of the resin tank is continuously cured into the shape of a cross sectional statue, thereby obtaining an aimed three dimensional formed object.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional molding apparatus.

0002

[Prior Art] A conventional three-dimensional molding device, as shown in FIG.
A laser light source 601 was scanned two-dimensionally using a laser scanning device 609 to form a cross-sectional image, and the images were laminated to form a three-dimensional object. (For example, O plus
E (1990) December issue p. See 117. )

00
03]

However, the conventional three-dimensional molding apparatus has a problem in that three-dimensional molding takes time because the resin is cured by two-dimensionally scanning laser light. The present invention is intended to solve these problems, and its purpose is to provide a high-performance three-dimensional molding device using simple means.

0004

[Means for Solving the Problems] A first three-dimensional molding apparatus of the present invention includes at least a liquid crystal spatial light modulator, a driving device for driving the liquid crystal spatial light modulator, and a curing material for curing the photocurable material. and an optical system for guiding light from the light source to the liquid crystal spatial light modulator.

[0005] A second three-dimensional molding apparatus of the present invention includes the first three-dimensional molding apparatus.
The three-dimensional molding apparatus is characterized in that the liquid crystal spatial light modulator is of a phase modulation type.

[0006] A third three-dimensional molding apparatus of the present invention includes the first three-dimensional molding apparatus.
The three-dimensional molding apparatus is characterized in that the liquid crystal spatial light modulator is of a simultaneous amplitude and phase modulation type.

[0007]

[Examples] The details of the present invention will be explained below with reference to Examples. (Example 1) FIG. 1 shows the configuration of a three-dimensional molding apparatus of the present invention. Laser light 112 emitted from laser light source 101 becomes parallel light that is expanded by beam expander 102 and collimating lens 103 . This laser light undergoes phase modulation by a computer-generated hologram recorded on the liquid crystal spatial light modulator 104 in ECB (electric field controlled birefringence) mode, and reproduces a three-dimensional cross-sectional image on the surface of the resin tank 105. The uncured resin 106 on the surface of the resin tank is cured by laser light irradiation. The molded product 107 is fixed to the table 108, and while the table is sent downward by the z-direction feeder 109, the uncured resin tanks that appear on the resin tank surface one after another are cured in the shape of a cross-sectional image, thereby forming a three-dimensional molded product. can get.

The ECB mode liquid crystal spatial light modulator is driven by a driving device 110 connected to a computer 111. The computer calculates a phase hologram from the cross-sectional image of the three-dimensional molded object by Fresnel transformation. The drive device sends a drive signal to the ECB mode liquid crystal spatial light modulator based on this hologram data. Since this hologram has a lens function, no lens is required between the ECB mode liquid crystal spatial light modulator and the resin layer.

The ECB mode liquid crystal spatial light modulator used in this example is an active matrix type in which each pixel is equipped with a TFT element (Proceedings of the 51st Annual Conference of the Japan Society of Applied Physics 26a-H-10 ) Since one cross-sectional image is cured at a time, a three-dimensional object can be formed in a much shorter time than the conventional method of two-dimensionally scanning a laser beam. Furthermore, by generating a cross-sectional image using a phase-type hologram, the efficiency of light utilization is higher than when using an amplitude-type light-shielding mask, and the resin can be cured in a short time. (Embodiment 2) FIG. 2 shows the configuration of another embodiment of the present invention. By changing the focal length of the lens used to record on the phase hologram, the position where the cross-sectional image is formed can be freely changed. By utilizing this property, the z-direction feeding device becomes unnecessary and the device is simplified. As in Example 1, the expanded parallel laser beam undergoes phase modulation by a computer-generated hologram recorded on an ECB mode liquid crystal spatial light modulator, and this time a three-dimensional cross-sectional image is reproduced inside the resin tank. A three-dimensional molded object can be formed by sequentially recording phase-type holograms with slightly different lens focal lengths on a liquid crystal spatial light modulator and reproducing cross-sectional images. (Example 3) The configuration of the third example is the EC in FIG.
The B-mode liquid crystal spatial light modulator is replaced with a simultaneous amplitude and phase modulation type liquid crystal spatial light modulator. FIG. 3 shows two configurations of the simultaneous amplitude and phase modulation type liquid crystal spatial light modulator used in this example. In FIG. 3A, a TN (twisted nematic) mode liquid crystal spatial light modulator 301 and an ECB mode liquid crystal spatial light modulator 302 are connected using an afocal optical system consisting of a pair of flat microlens arrays 303 and 304. , optically connected. f in the figure represents the focal length of the lens. In FIG. 3(b), two liquid crystal spatial light modulators 30
1 and 302 were optically connected using an afocal optical system consisting of a lens 305 and a lens 307. Additionally, a spatial filter 306 was placed between lenses 305 and 307 to remove unnecessary light. The TN mode liquid crystal spatial light modulator and the ECB mode liquid crystal spatial light modulator are active matrix types each having a TFT element.

By using this simultaneous amplitude and phase modulation type liquid crystal spatial light modulator, almost perfect wavefront control can be performed. Therefore, for example, if a computer calculates an optically converted image of a three-dimensional surface shape and irradiates a laser beam onto a simultaneous amplitude and phase modulation type liquid crystal spatial light modulator that records this data,
A three-dimensional surface image can be directly reproduced in the resin bath. Utilizing this, in this example, the three-dimensional surface was first hardened quickly. However, the material was hardened starting from the surface of the object itself, which was in the shadow. Thereafter, this molded product was taken out of the resin bath and the inside was cured by irradiating it with strong light. (Embodiment 4) FIG. 4 shows the configuration of a fourth embodiment of the present invention. This is achieved by arranging a plurality of optical systems in Example 3 around the resin tank, thereby increasing the molding speed and making it possible to form a complex shape. For example, even if a solid body has a non-connected cross section as shown in FIG. 5, its surface can be hardened at one time. This enabled three-dimensional molding to be performed in close to real time. Furthermore, even complex shapes that cannot be cured at once can be quickly formed by rewriting the data in the liquid crystal spatial light modulator.

Furthermore, since the optical system using the liquid crystal spatial light modulator of the present invention can generate a light spot at any point in space, it can also be used in a conventional laser beam scanning method. can.

0012

[Effects of the Invention] According to the present invention, the following effects can be obtained. (1) By reproducing a cross-sectional image using a liquid crystal spatial light modulator, two-dimensional laser beam scanning becomes unnecessary, and the time for three-dimensional molding can be significantly shortened. Further, if a simultaneous amplitude and phase modulation type liquid crystal spatial light modulator is used, a three-dimensional image can be directly formed, so three-dimensional molding can be performed in close to real time. (2) By providing a phase-type hologram with a lens function and changing its focal length, the cross-sectional image can be swung back and forth, eliminating the need for any moving parts such as a feeding device, and greatly simplifying the device. In other words, since the number of parts is reduced, costs and size can be reduced. (3) If a simultaneous amplitude and phase modulation type liquid crystal spatial light modulator is used, a three-dimensional image can be directly formed, so even a shape that is difficult to mold using a method of stacking cross-sectional images can be easily molded.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a three-dimensional molding apparatus of the present invention.

FIG. 2 is a side view showing another configuration of the three-dimensional molding apparatus of the present invention.

FIG. 3(a) is a side view showing the configuration of a simultaneous amplitude and phase modulation type liquid crystal spatial light modulator. (b) It is a side view which shows another structure of an amplitude phase simultaneous modulation type liquid crystal spatial light modulator.

FIG. 4 is a side view showing another configuration of the three-dimensional molding apparatus of the present invention.

FIG. 5(a) is a perspective view showing an example of a three-dimensional molded product. (b) is a cross-sectional view when the molded product 501 is cut along a plane 502;

FIG. 6 is a side view showing the configuration of a conventional three-dimensional molding device.

[Explanation of symbols]

101 Laser light source 102 Beam expander 103 Collimating lens 104 ECB mode liquid crystal spatial light modulator 105
Resin tank 106 Resin 107 Molded product 108 Table 109 Z-direction feed device 110 Drive device 111 Computer 112 Laser beam 301 TN mode liquid crystal spatial light modulator 302 E
CB mode liquid crystal spatial light modulator 303 Microlens array 304 Microlens array 305 Lens 306 Spatial filter 307 Lens 501 Molded article 502 Plane 503 Cross section of molded article 601 Laser light source 602 Condensing lens 609 Laser scanning device 610 Control device 611 Computer 612 laser light

Claims (3)

[Claims] 1. A three-dimensional molding device for molding a photocurable material, comprising at least a liquid crystal spatial light modulator, a driving device for driving the liquid crystal spatial light modulator, and a light source for curing the photocurable material. and an optical system for guiding light from the light source to the liquid crystal spatial light modulator. 2. The three-dimensional molding apparatus according to claim 1, wherein the liquid crystal spatial light modulator is of a phase modulation type. 3. The three-dimensional molding apparatus according to claim 1, wherein the liquid crystal spatial light modulator is of a simultaneous amplitude and phase modulation type.