JP3854320B2 - Photo-curing modeling equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a photo-curing modeling apparatus including an optical shuttering device that switches between a state in which a light beam passes and a state in which the light beam is blocked.
[0002]
[Prior art]
In the photo- curing modeling apparatus , an optical shuttering apparatus that switches between a state where a light beam such as a laser beam passes and a state where it is blocked is required at high speed. An example of a conventional optical shuttering device will be described with reference to FIG. FIG. 4 is a plan view showing a configuration of a conventional optical shuttering device. As shown in FIG. 4, in the conventional optical shuttering device 52, (abbreviated Acousto-Optic Modulator, hereinafter to as "AOM") with a laser light beam 56 emitted from the laser light source 54 acousto-optical modulator The light is incident on the module 60. The AOM module 60, by ultrasonic predetermined frequency is applied, the deflection of the laser beam 56 is performed. That is, in a state where no ultrasonic wave is applied, the laser light beam 56 is emitted as 0th-order light 56 </ b> B that travels straight. In addition, in a state where an ultrasonic wave is applied, the laser light beam 56 is emitted as primary light 56A deflected by an angle θ. Of these, the zero-order light 56 </ b> B is blocked by the slit 72, and only the deflected primary light 56 </ b> A passes through the opening 72 a of the slit 72. Therefore, by switching between the state in which the ultrasonic wave is applied to the AOM module 60 and the state in which the ultrasonic wave is not applied at high speed, the state in which the laser light 56 passes and the state in which the laser light 56 passes can be switched at high speed.
[0003]
[Problems to be solved by the invention]
However, the deflection angle by such a high-speed optical deflector such as the AOM module 60 is extremely small. In FIG. 4, the deflection angle θ is drawn much larger than the actual angle for the sake of clarity, but the deflection angle θ by the AOM module 60 is actually extremely small, about 4.24 mrad (about 0.25 °). Therefore, in order to completely separate the zero-order light 56B and the primary light 56A by the slit 72, the distance L10 from the AOM module 60 to the slit 72 needs to be as long as 1 m. For this reason, the total length of the optical shuttering device 52 becomes long, and the miniaturization of the photocuring modeling apparatus provided with the optical shuttering device is hindered. In addition, since the optical path becomes longer in this way, the influence of optical aberration on the light source, lens, mirror, etc. is enlarged, and the minimum focused diameter of the light beam is increased. Further, the optical axis shift due to the temperature change of the light source is amplified by the length of the optical path, and there is a problem that the accuracy of the three-dimensional model formed by the photo-curing modeling apparatus is deteriorated.
[0004]
Therefore, in this onset bright, and an object thereof is to provide a photocurable molding apparatus the device by shortening the optical path can be miniaturized. Further, in this onset bright, the above object can be accomplished easily and reliably, and the optical system changes the depth of the minimum focal point that is required for photocuring shaping apparatus and optical shuttering device composite An optical curing modeling apparatus is provided.
[0005]
[Means for Solving the Problems]
請 Motomeko inventions according to 1, galvanometer mirror for changing a light source for emitting a light beam, a light shuttering device for switching between the state of being shut off in a state in which the light beam passes through, the traveling direction by reflecting the light beam And a photo-curing modeling apparatus including a container for storing a photo-curable liquid resin. In this photo-curing modeling apparatus, the spot of the light beam can be directed to an arbitrary position within the liquid surface of the photo-curable liquid resin contained in the container by the galvano mirror, and the light shuttering apparatus Depending on the position in the liquid surface of the photocurable liquid resin accommodated in the liquid crystal, it is possible to switch whether or not to irradiate the spot of light. That is, it is possible to irradiate an arbitrary position in the liquid surface with a light beam spot and not to irradiate it.
The light shuttering device includes an optical deflector for changing the traveling direction of the light beam, a condenser lens for the light beam emitted from the light deflector for focusing, a spatial filter provided in the focal plane of the condenser lens it characterized in that it has. Here, the focal plane of the condenser lens means a plane that includes the focal point of the condenser lens and is perpendicular to the optical axis of the condenser lens.
[0006]
Moreover, the photocuring modeling apparatus of the present invention is characterized in that a condensing lens constituting a beam expander is used for the condensing lens.
In addition, a second condenser lens is disposed behind the spatial filter. That is, a pair of condensing lenses are arranged before and after the spatial filter. The pair of condensing lenses constitutes a beam expander. The 1st condensing lens arrange | positioned ahead of a spatial filter serves as the structural member of an optical shuttering apparatus and a beam expander.
The photo-curing modeling apparatus of the present invention is characterized in that the second condensing lens (the condensing lens arranged behind the spatial filter) constituting the beam expander is movable along the optical axis of the light beam. And
[0007]
[Action]
Now, the photocurable molding apparatus according to claim 1 is provided with a light shuttering device for switching between the state in which the light beam is shut off in a state that passes, the light shuttering device, to change the traveling direction of the ray It has an optical deflector, a condensing lens for condensing the light beam emitted from the optical deflector, and a spatial filter provided on the focal plane of the condensing lens. The light beam emitted from the optical deflector enters the condenser lens and is condensed on the focal plane of the condenser lens. Here, the position where light is collected by the condensing lens differs depending on whether the light beam emitted from the optical deflector is not deflected or deflected (the traveling direction is changed). That is, the condensing lens functions as a Fourier transform lens, and it can be considered that the Fourier transform images of the undeflected light beam and the deflected light beam are formed at points having different spatial frequencies. Therefore, it is possible to block only one component of these Fourier transform images and allow the other component to pass through the spatial filter placed on the focal plane of the condenser lens. That is, one of the undeflected light beam and the deflected light beam can be blocked and the other can be passed. As a result, by switching between the state where the light beam is not deflected by the optical deflector and the deflected state, the state where the light beam passes and the state where the light beam is blocked can be switched.
[0008]
In this optical shuttering device utilizes the fact that the Fourier transform image by the condensing lens is focused at different points spatial frequency from each other by or not or light is deflected. For this reason, it is not necessary that the light beams are separated from each other. If there is a slight difference in deflection angle, only one light beam can be blocked by the spatial filter. Accordingly, optical shuttering can be performed even if a condenser lens and a spatial filter are arranged immediately after the optical deflector. As a result, the optical path in the optical shuttering device can be remarkably shortened compared to the conventional device, and the device can be miniaturized. In this way, Ru can be miniaturized photocurable molding apparatus.
[0009]
Moreover, in the photocuring modeling apparatus of this invention, the condensing lens which comprises a beam expander is used for said 1st condensing lens. As this beam expander, a combination of a condensing lens and a collimating lens is used. In an optical apparatus using such a beam expander, an optical deflector is disposed in front of the beam expander, and a spatial filter is disposed on the focal plane of the first condenser lens that constitutes the beam expander. In this way, optical shuttering can be performed. Accordingly, the optical path in the optical shuttering device can be remarkably shortened while minimizing the addition of optical elements in the optical apparatus, and the photo-curing modeling apparatus can be downsized.
Furthermore, in the photo-curing modeling apparatus of the present invention, the first condenser lens disposed in front of the spatial filter serves as both the optical shuttering device and the component of the beam expander. The number of optical elements can be reduced.
In the photo-curing modeling apparatus of the present invention, the second condensing lens constituting the beam expander can be moved along the optical axis. And the curing depth of the liquid resin can be changed.
[0010]
【Example】
Next, an embodiment embodying the present invention will be described with reference to FIGS. First, a structure and function of each of the light-curing stereolithography apparatus using an optical shuttering device of the present embodiment will be described with reference to FIGS. The photo-curing modeling apparatus is a liquid photo-curing resin (hereinafter also abbreviated as “liquid resin”) that is irradiated with a strong light beam such as laser light to cure a part of the photo-curing modeling apparatus. It is a device for modeling. This photo-curing modeling apparatus can easily materialize machine parts and the like designed by a CAD system using CAD data, and can perform design confirmation and direct evaluation. In addition, it is an extremely useful device that is compatible with the recent demand for high-mix low-volume production. FIG. 1 is a plan view showing a configuration of a photo-curing modeling apparatus using the optical shuttering apparatus of the present embodiment, and FIG. 2 is a front view thereof. 1 and 2 show only the configuration of the optical system that is the center of the photo-curing modeling apparatus, and support mechanisms and drive mechanisms such as mirrors and lenses are omitted.
[0011]
As shown in FIG. 1, the photo-curing modeling apparatus 2 in the present embodiment has a He—Cd laser 4 as a laser light source. The ultraviolet laser beam 6 emitted from the He-Cd laser 4 is reflected by the total reflection mirror 8 and enters the AOM module 10. The ultraviolet laser beam 6 incident on the AOM module 10 is emitted as a 0th-order light traveling straight or a slightly deflected primary light, and reflected by the total reflection mirror 12 in a direction directly below (direction perpendicular to the paper surface of FIG. 1). Further, the light is reflected by the total reflection mirror 14 in the horizontal direction.
Therefore, this AOM module 10 functions as an optical deflector in the present invention. The AOM module 10 also has a function of changing the intensity of the ultraviolet laser light 6 irradiated to the liquid resin 40 described later.
That is, by changing the power of the ultrasonic wave applied to the AOM module 10, the intensity ratio between the 0th order light and the 1st order light is changed. As will be described later, since only the primary light of the ultraviolet laser beam 6 is finally irradiated to the liquid resin 40, the liquid resin 40 is changed by changing the intensity ratio between the zero-order light and the primary light. The intensity of the irradiated ultraviolet laser beam 6 changes.
[0012]
Subsequently, the ultraviolet laser light 6 passes through the mechanical shutter 16 and the iris diaphragm 18 and enters the convex lens 20 constituting the beam expander. The convex lens 20 and the convex lens 24 constitute a beam expander for expanding the beam diameter of the ultraviolet laser light 6.
A spatial filter 22 is provided between the convex lens 20 and the convex lens 24. The spatial filter 22 is located at the focal point of the convex lens 20, and a slit is used as the spatial filter 22 in this embodiment.
The AOM module 10 described above, the convex lens 20 and the spatial filter 22 constitute the optical shuttering device 1 of the present embodiment.
[0013]
The mechanism of optical shuttering by the optical shuttering device 1 will be described with reference to FIG. FIG. 3 is a plan view showing the configuration of the main part of the optical shuttering device 1 of the present embodiment.
The 0th order laser beam 6B and the 1st order laser beam 6A emitted from the AOM module 10 shown in FIG. 1 enter the convex lens 20 from the right side of FIG. Here, the convex lens 20 is installed such that its optical axis coincides with the optical path of the primary light 6A. Therefore, the 0th-order light 6B is incident on the optical axis of the convex lens 20 with a deflection angle.
The primary light 6 </ b> A incident along the optical axis of the convex lens 20 is collected at a point 6 </ b> C on the optical axis of the convex lens 20. On the other hand, the 0th-order light 6B having a deflection angle with respect to the optical axis of the convex lens 20 is collected at a point 6D away from the point 6C. That is, the convex lens 20 functions as a Fourier transform lens, and it can be considered that the Fourier transform images of the primary light 6A and the zeroth-order light 6B are formed at points 6C and 6D having different spatial frequencies.
[0014]
Therefore, only the component (0th-order light 6B) of the point 6D having a different spatial frequency in these Fourier transform images can be blocked by the slit 22 as a spatial filter. On the other hand, the primary light 6 </ b> A collected at the point 6 </ b> C passes through the opening 22 a of the slit 22 and enters the second convex lens 24. And it is radiate | emitted as the parallel light 6E with which the beam diameter was expanded.
In this way, the 0th-order light 6B of the laser light emitted from the AOM module 10 is blocked by the spatial filter 22, and only the primary light 6A passes through the spatial filter 22. Accordingly, the AOM module 10 switches the ultraviolet laser beam 6 between the 0th-order light 6B and the primary light 6A at high speed, thereby shuttering the ultraviolet laser light 6 at a high speed corresponding to the scanning speed of the galvanometer mirrors 28 and 30. It becomes possible.
Thereby, it is possible to irradiate only a necessary portion of the liquid resin 40 while scanning the ultraviolet laser beam 6 at a high speed.
[0015]
In this embodiment, due to the support mechanism and the like, as shown in FIG. 1, total reflection mirrors 12 and 14, a mechanical shutter 16 and an iris diaphragm 18 are arranged between the AOM module 10 and the convex lens 20. The AOM module 10 and the convex lens 20 are separated from each other.
However, for optical shuttering using the spatial filter 22, it is not necessary to separate the optical path of the 0th-order light and the optical path of the primary light as in the conventional optical shuttering device 52. It is sufficient that a slight deflection angle exists. Therefore, it is not necessary to separate the AOM module 10 from the convex lens 20, and an optical shuttering device that functions similarly can be configured even if the convex lens 20 and the spatial filter 22 are arranged immediately after the AOM module 10.
As a result, the optical shuttering device can be a device having an extremely short optical path length as compared with the conventional optical shuttering device 52.
[0016]
As shown in FIGS. 1 and 2, the convex lens 24 is movable along the optical axis direction of the ultraviolet laser beam 6. The moving mechanism of the convex lens 24 is configured by attaching the lens holder of the convex lens 24 to a slide stage (both not shown) using a pulse motor.
By moving the convex lens 24 by such a moving mechanism, the minimum condensing point of the ultraviolet laser beam 6 is shifted up and down from the liquid surface of the liquid resin 40, and as a result, the spot diameter of the ultraviolet laser beam 6 on the liquid surface of the liquid resin 40 is increased. Change. Thereby, the curing depth of the liquid resin 40 can be changed without changing the curing diameter of the liquid resin 40 by the ultraviolet laser beam 6.
[0017]
The ultraviolet laser beam 6 having an enlarged beam diameter emitted from the convex lens 24 passes through the second iris diaphragm 26 and is reflected by the galvanometer mirrors 28 and 30. The galvano mirror 28 rotates about a rotation axis perpendicular to the paper surface of FIG. 1, and the galvano mirror 30 rotates about a rotation axis in the paper surface of FIG. As a result, as indicated by a broken line in FIG. 2, the ultraviolet laser beam 6 is scanned over the entire surface of the resin container 38 provided below the galvanometer mirror 30.
As shown in FIG. 2, an fθ lens 32 is provided between the galvanometer mirror 30 and the resin container 38. The fθ lens 32 is configured by combining several lenses, and condenses the ultraviolet laser beam 6 with a uniform spot diameter over the entire surface of the liquid resin 40 in the resin container 38.
The two iris diaphragms 18 and 26 are used only for aligning the optical axis of the ultraviolet laser beam 6 when assembling the photo-curing modeling apparatus 2, and are fully opened after the optical axis alignment is completed. The Further, the mechanical shutter 16 is closed for the safety of the operator when working around the resin container 38, and is fully opened when the photo-curing modeling apparatus 2 is used.
[0018]
Now, the procedure of photocuring modeling using the photocuring modeling apparatus 2 of the present embodiment having such a configuration will be described with reference to FIG.
As shown in FIG. 2, in the photo-curing modeling apparatus 2, an elevating table 42 that can be raised and lowered by an elevating mechanism (not shown) is provided in a container 38 filled with a liquid resin 40. In order to form the product 44 as shown in the figure, the elevating table 42 is first positioned at a height lowered from the liquid level 40 a of the liquid resin 40 by the thickness of the lowermost layer 44 a of the product 44. In this state, the galvanometer mirrors 28 and 30 are rotated to scan the entire surface of the liquid resin 40 with the laser beam 6 and irradiate the laser beam 6 only within a necessary range. That is, within the range of the product 44, the ultraviolet laser light 6 is switched to the primary light 6 </ b> A by the AOM module 10, and the liquid resin 40 is irradiated through the slit 22. In other ranges, the AOM module 10 switches the ultraviolet laser light 6 to the 0th-order light 6B and is blocked by the slit 22 so that the liquid resin 40 is not photocured.
In this way, the lowermost layer 44a is first photocured. Next, the lifting table 42 is lowered from the lowermost layer by the thickness of the second layer 44b, and the second layer 44b is similarly photocured. In the same manner, the product 44 as shown in FIG. 2 is formed by photocuring one layer at a time from the bottom.
[0019]
In this embodiment, an example in which the optical shuttering device of the present invention is applied to a photo-curing modeling apparatus has been described. However, the optical shuttering device of the present invention can also be applied to various other optical devices. Moreover, although applied to the ultraviolet laser beam 6 emitted from the He-Cd laser 4 as a light beam, other ultraviolet laser beams such as an Ar laser, laser beams of other wavelengths, and other than laser beams It can also be applied to light rays.
In this embodiment, the AOM module is used as the optical deflector, but other optical deflectors such as an EOM (Electro-Optic Modulator) module may be used.
Furthermore, in the present embodiment, a slit is used as the spatial filter 22, but a pinhole or a mask pattern drawn on a glass plate may be used as the spatial filter.
The configuration, function, number, size, connection relationship, and the like of other parts of the optical shuttering device are not limited to the present embodiment.
[0020]
【The invention's effect】
In the invention according to claim 1, in order to create a photocurable molding apparatus utilizing light shuttering device which is constructed by combining the optical deflector and the condenser lens and the spatial filter, as compared to the conventional photo-curing stereolithography apparatus The optical path in the optical shuttering apparatus can be remarkably shortened, and the photocuring modeling apparatus can be downsized. Accordingly, it is possible to improve the accuracy of the three-dimensional model formed by the photo-curing modeling apparatus while minimizing the influence of optical aberration and optical axis shift .
[0021]
In the invention according to claim 2, since the optical shuttering device in which the optical deflector and the spatial filter are arranged before and after the front-side condenser lens constituting the beam expander is created, the addition of optical elements is reduced as much as possible. However, the optical path in the optical shuttering apparatus can be remarkably shortened, and the photo-curing modeling apparatus can be downsized.
Moreover, in the photocuring modeling apparatus which concerns on Claim 3, the condensing lens arrange | positioned ahead of the spatial filter serves as the structural member of an optical shuttering apparatus and a beam expander. The number of optical elements can be reduced.
Furthermore, in the photocuring modeling apparatus according to claim 4, the minimum condensing point of the light beam can be adjusted in the vertical direction with respect to the liquid surface, and the curing depth of the liquid resin can be changed.
[Brief description of the drawings]
FIG. 1 is a plan view showing a configuration of a photo-curing modeling apparatus to which an embodiment of an optical shuttering apparatus according to the present invention is applied.
FIG. 2 is a front view showing a configuration of a photo-curing modeling apparatus to which an embodiment of an optical shuttering apparatus is applied.
FIG. 3 is a plan view showing a configuration of a main part of an embodiment of the optical shuttering device.
FIG. 4 is a plan view showing a configuration of a conventional optical shuttering device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical shuttering apparatus 6 Light beam 10 Optical deflector 20 Condensing lens 22 Spatial filter

Claims (1)

A photo-curing modeling apparatus, a light source that emits light, an optical shuttering device that switches between a state in which the light passes and a state in which the light passes, a galvano mirror that reflects the light and changes the traveling direction, and photo-curing A container for storing the liquid crystalline resin,
With the galvanometer mirror, the light spot can be directed to any position within the liquid level of the photocurable liquid resin contained in the container,
It is a photo-curing modeling apparatus that can switch whether or not to irradiate a spot of light according to the position within the liquid surface of the photo-curable liquid resin contained in the container by the optical shuttering device,
The light shuttering device includes an optical deflector for changing the traveling direction of the light beam, a first condensing lens for condensing light beams emitted from the light deflector, disposed in the focal plane of the first condenser lens It was to have a spatial filter,
A second condenser lens is disposed behind the spatial filter, and the first condenser lens and the second condenser lens form a pair to constitute a beam expander;
The photo-curing modeling apparatus, wherein the second condenser lens is movable along the optical axis of the light beam .

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