JPH11170377A - Stereolithography processing method, movable device using the processing method, and stereolithography processing apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To solve the problem of peeling of a cured layer and to further improve the processing resolution. SOLUTION: An optical shaping apparatus 1 using an optical shaping method for irradiating light to a liquid photocurable resin 5 to cure the photocurable resin 5 into a desired shape is configured. In this case, the laser oscillator 2, the lens 4 for condensing the laser beam L emitted from the laser oscillator 2, and the liquid photocurable resin 5 to which the laser beam L condensed by the lens 4 is irradiated The focal point of the laser beam L condensed by the lens 4 is arranged between the stage 6 to be mounted and the laser oscillator 2 and the lens 4, and by expanding the beam width of the laser beam L emitted from the laser oscillator 2. A beam expander 3 is provided to make only the portion F have the energy intensity necessary for curing the photocurable resin 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereolithography process, a movable device manufactured by using the stereolithography process, and a stereolithography device.

[0002]

2. Description of the Related Art As a processing method of mechanical parts, an optical molding processing method has been put to practical use. In general, the photolithography processing method is a processing method of irradiating light to a liquid state photocurable resin to cure the photocurable resin into a desired shape, and is a method suitable for obtaining a complicated three-dimensional shape. is there.

[0003] The inventor of the present application has been conducting research and development for practical use of this stereolithography as a basic technology of a micromachine, which is expected to be greatly applied to the medical field, for many years.

In order to apply stereolithography to three-dimensional microfabrication for micromachines, a processing resolution is required.
It is necessary to make the minimum curing unit of the photocurable resin as small as possible.

[0005] By the way, in the conventional stereolithography method, FIG.
And a method called a free liquid level method as shown in FIG. In the example shown in FIG. 9, first, a liquid photo-curable resin 110 is placed so that the bottom 100 of the container is covered thinly, and the liquid surface is irradiated with light L such as ultraviolet rays. Then, only the portion irradiated with the light L is hardened and solidified (see the hardened layer in FIG. 1A).

Next, a liquid photocurable resin 110 is added to raise the liquid level so that the upper surface of the cured layer is covered with the photocurable resin 110 thinly. When light L is applied to the liquid surface from this state, the photocurable resin is cured, and a second cured layer is formed on the first cured layer (see FIG. 9B). Hereinafter, by repeating the same operation, a three-dimensional shape in which many layers are stacked is formed.

In FIG. 10, unlike in FIG. 9, cured layers are formed one after another on a vertically movable stage 120. That is, first, a certain amount of the liquid photocurable resin 110 is put into the container, and the stage 120 is moved upward, so that a thin layer of the liquid photocurable resin 110 is formed between the stage upper surface 120a and the liquid surface. To do.

[0008] From this state, the liquid surface is irradiated with light L and cured to form a first cured layer (FIG. 1).
0 (a)). Next, the stage 120 is lowered by one stage, and the liquid photo-curable resin 110 is placed between the cured layer and the liquid surface.
Is formed, and the liquid surface is irradiated with light L from this state to form a second hardened layer (see FIG. 2B). Hereinafter, by repeating the same operation, a three-dimensional shape composed of many layers is formed.

In such a free liquid level method, the thinner the liquid layer, the more difficult it becomes to make the whole a uniform thickness due to the influence of surface tension. Therefore, the thickness of one hardened layer is controlled. This is not easy and the resolution cannot be increased. In addition, since the viscosity of the liquid photocurable resin is generally high, there is a problem that it takes time until the liquid surface is stabilized.

On the other hand, in the conventional stereolithography method, FIG.
There is a method called a liquid level regulation method as shown in FIG. In FIG. 11, first, a fixed amount of the liquid photocurable resin 110 is put in a container. From this state, the light-transmissible vertically movable stage 130 is moved downward so that a thin layer of the liquid photocurable resin 110 is formed between the stage lower surface 130a and the container bottom surface 140.

Next, the light curable resin 110 is irradiated with light L from above through the stage 130 to be cured, thereby forming a first cured layer (see FIG. 11A). Next, the stage 130 is raised by one step, a thin layer of liquid photocurable resin is formed between the stage lower surface 130a and the cured layer, and the light curable resin 110 is irradiated with light L from this state, A second hardened layer is formed (see FIG. 3B). Hereinafter, by repeating the same operation, a three-dimensional shape composed of many layers is formed.

In FIG. 12, a transparent window 150 is provided at the bottom of the container, and light L is emitted from the transparent window 150. That is, in this case, first,
A certain amount of the liquid photocurable resin 110 is put in the container, and the stage 160 is moved downward to
The liquid photo-curing resin 11 between the container 60a and the container bottom surface 170
Form a thin layer of zero.

In this state, the light curable resin 110 is irradiated with light L from below through the transparent window 150 to be cured, thereby forming a first cured layer (FIG. 12A).
reference). Next, the stage 160 is raised by one step together with the cured layer to form a thin layer of the liquid photocurable resin 110 between the cured layer and the container bottom surface 170. By irradiating the cured resin 110 with light L, a second cured layer is formed. Less than,
By repeating the same operation, a three-dimensional shape composed of a number of layers is formed (see FIG. 3B).

In such a liquid surface regulation method, since the distance by which the stage is raised is equivalent to the thickness of the layer, it is relatively easy to control the thickness of one hardened layer, and the resolution is increased to some extent. This has the advantage that the processing can be performed faster because there is no need to wait for the liquid surface to stabilize, but when the stage is raised, the hardened layer is placed on the stage lower surface 130a or the transparent window. 1
It is necessary to completely separate the mold from the surface of the stage, and therefore, it is necessary to apply a release agent to the lower surface of the stage or the transparent window, or to perform a process such as Teflon coating.

However, even when such a treatment is performed, the interface of the hardened layer does not always completely peel off from the lower surface of the stage or the transparent window, and peeling occurs inside the hardened layer, resulting in deformation or breakage into a three-dimensional shape. May occur.

In this liquid level regulation method, it is necessary to reduce the moving distance of the stage as much as possible in order to further improve the processing resolution. However, if the moving distance of the stage becomes too small, the stage is moved. Even when the cured layer is elastically deformed, the interface of the cured layer may not be separated. Therefore, the processing resolution is limited by the liquid level regulation law.

The present invention has been made in view of such a conventional situation, and has as its object to solve the problem of peeling of a hardened layer and to further improve the processing resolution, and to provide an optical molding method and method. It is an object of the present invention to provide a movable device and an optical shaping apparatus using the method.

[0018]

According to a first aspect of the present invention, there is provided a stereolithography method for irradiating a liquid photocurable resin with light to cure the photocurable resin into a desired shape. Therefore, while confining the liquid photocurable resin in a certain space, and condensing the light beam to be irradiated after expanding the width of the light beam, only the focal portion of the light beam is necessary for curing the photocurable resin. The energy intensity is set, and from this state, a light beam is applied to the inside of the photocurable resin.

According to a second aspect of the present invention, there is provided a movable device including a movable member, wherein the movable device is manufactured by using the stereolithography method according to the first aspect.

According to a third aspect of the present invention, in the second aspect, the movable device is a movable device for a micromachine, and the movable member is a rotating body or a sliding body.

According to a fourth aspect of the present invention, there is provided a stereolithography apparatus.
An optical shaping apparatus for irradiating a liquid photocurable resin with light to cure the photocurable resin into a desired shape, comprising: a laser oscillator for emitting a laser beam; and a laser emitted from the laser oscillator. A lens for condensing the beam, a stage which is confined within a certain space, and on which a liquid photocurable resin to be irradiated with the laser beam condensed by the lens is mounted; and The laser beam emitted from the laser oscillator is disposed between the laser oscillators so as to widen the beam width, so that only the focal portion of the laser beam focused by the lens has the energy intensity necessary for curing the photocurable resin. And a focus moving means for moving the focal point of the laser beam inside the photocurable resin.

According to a fifth aspect of the present invention, there is provided a stereolithography apparatus.
According to a fourth aspect of the present invention, the focal point moving means comprises at least one of a beam moving mechanism for moving a beam and a stage moving mechanism for moving a stage.

According to the stereolithography method according to the first invention,
The light beam applied to the photocurable resin is condensed after its beam width is expanded, and is applied to the photocurable resin, and only the focal point of the light beam has the energy required for curing the photocurable resin. Has strength.

For this reason, when irradiating a liquid light curable resin confined in a certain space with a light beam, the focal point of the light beam may be arranged at a portion to be cured in the light curable resin. In the photocurable resin, only the focal portion of the light beam is cured, and no curing occurs at other irradiated portions of the light beam. Therefore, if the focal point of the light beam is moved inside the photocurable resin, a desired three-dimensional shape can be obtained.

As described above, in the present invention, in order to form a desired three-dimensional shape, the focal point of the light beam may be moved inside the photocurable resin, so that the elevating stage becomes unnecessary.
As a result, the problem of peeling of the cured layer can be solved.

In addition, when the light beam is irradiated, only the focal point of the light beam is hardened, so that the processing resolution can be greatly improved.

[0027] A movable device according to a second aspect of the present invention includes a movable member, and is manufactured by the stereolithography method according to the first aspect of the present invention. That is, in this case, by moving the focal point of the light beam inside the photocurable resin, the movable member such as a rotating body or a sliding body is cured within the photocurable resin without forming a support portion such as a stay.・ Can be formed.

In the optical modeling apparatus according to the third invention, a laser beam emitted from a laser oscillator is incident on a lens via a beam expander and is condensed by the lens. The cured resin is irradiated.

In this case, the laser beam incident on the lens has its beam width expanded by the beam expander, so that only the focal point of the laser beam condensed by the lens is cured by the liquid photo-curing resin. Energy state required for

Therefore, when irradiating a laser beam to the liquid photo-curable resin placed on the stage, the focus of the laser beam may be arranged at a portion to be cured in the photo-curable resin. Inside the photocurable resin, only the focal point of the laser beam is cured, and no curing occurs at other irradiated portions of the laser beam. Therefore, a desired three-dimensional shape can be obtained by moving the focal point of the laser beam inside the photocurable resin by the focal point moving means.

As described above, in the present invention, a desired three-dimensional shape can be formed by moving the focal point of the laser beam inside the photocurable resin. Can be eliminated.

Further, at the time of laser beam irradiation, only the focal point of the laser beam is hardened, so that the processing resolution can be greatly improved.

Preferably, the focal point moving means for moving the focal point of the laser beam inside the photocurable resin comprises at least one of a beam moving mechanism and a stage moving mechanism. That is, the focal point of the laser beam may be moved in the X, Y, and Z axis directions by only the beam moving mechanism or only the stage moving mechanism. The direction may be moved by a stage moving mechanism.

[0034]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an optical modeling apparatus according to an embodiment of the present invention. As shown in FIG. 1, the laser shaping apparatus 1 has passed through a laser oscillator 2, a beam expander 3 for expanding a beam width of a laser beam L emitted from the laser oscillator 2, and a beam expander 3. It mainly includes a lens 4 for condensing the laser beam L, and a stage 6 on which a photocurable resin 5 to be irradiated with the laser beam L condensed by the lens 4 is mounted.

A shutter 7 and a filter 8 for adjusting the amount of light are arranged in front of the laser oscillator 2. Further, a mirror (or prism) 9 for guiding the laser beam L emitted from the laser oscillator 2 to the beam expander 3 is provided.

Between the beam expander 3 and the lens 4, there is provided a beam moving mechanism 10 such as a galvanometer mirror for moving the laser beam L at high speed in the X, Y, and Z axis directions. Here, the left-right direction in the figure is the X-axis direction, the direction perpendicular to the paper surface is the Y-axis direction, and the up-down direction in the figure is the Z-axis direction. Further, the shutter 7 and the beam moving mechanism 10
It is controlled by a control signal from a control unit (not shown).

As shown in FIG. 2, the liquid photo-curing resin 5 is contained in a fixed space formed by a light-transmitting base 11, spacers 12, 13 and a lid 14.

Next, an optical molding method using the optical molding apparatus according to this embodiment will be described. Laser oscillator 2
Is transmitted through the shutter 7 and the filter 8, is reflected by the mirror 9, and enters the beam expander 3. The beam width of the laser beam L incident on the beam expander 3 is expanded in the beam expander 3. That is, a thin parallel light beam before the incidence is changed to a thick parallel light beam after the emission.

The laser beam L emitted from the beam expander 3 enters the lens 4 via the beam moving mechanism 10, is condensed by the lens 4, and is incident on the photocurable resin 5 on the stage 6 (FIG. 2). reference).

At this time, since the beam width is expanded by the beam expander 3, as shown in FIG. 3, the opening angle α of the laser beam L incident on the photocurable resin 5 is large, for example, an obtuse angle. I have. Accordingly, when the energy intensity E of the laser beam L is taken on the vertical axis (the axis taken in the depth direction of the photocurable resin 5), only the portion of the focal point F of the laser beam L cures the liquid photocurable resin 5. The required energy intensity (critical intensity) ε ₀ has been reached, and the energy intensity of the other irradiation area A of the laser beam L is smaller than ε ₀ .

That is, in the photocurable resin 5 irradiated with such a laser beam L, only the portion of the focal point F of the laser beam L is cured, and no curing occurs in the other irradiation area A.

Therefore, in order to obtain a desired three-dimensional shape from the photo-curable resin 5, the laser beam L is applied to the photo-curable resin 5 such that the focal point F of the laser beam L is located in the liquid, that is, on the back side of the liquid surface 5a. And the laser beam L is moved in the X, Y, and Z-axis directions by the beam moving mechanism 10 to move the focal point F inside the photocurable resin 5. Thereby, as shown in FIG. 2, a desired three-dimensional shape 20 is cured and formed inside the photocurable resin 5.

In the conventional stereolithography method, as shown in FIG. 4, the divergence angle of the laser beam L 'used is small, and as in FIG. Then, the liquid surface 5a of the photocurable resin 5 has reached the critical intensity ε ₀ , and the entire irradiation area A ′ of the laser beam L ′ in the liquid is placed in an energy state necessary for curing the photocurable resin 5. ing. Therefore, the photocurable resin 5 is cured in the entire irradiation area A 'of the laser beam L'. For this reason, the processing resolution is low in the conventional method.

On the other hand, in the optical shaping method according to the present invention, only the portion of the focal point F of the laser beam L is cured in the photocurable resin 5, so that the processing resolution is greatly improved. Thus, a microstructure for a micromachine can be easily manufactured.

When a desired three-dimensional shape is formed in the present embodiment, the laser beam L is applied to the inside of the photocurable resin 5 confined in a certain space,
Since the focal point F of the laser beam L may be appropriately moved inside the photo-curing resin 5, it is not necessary to move the cured layer of the photo-curing resin 5 together with the elevating stage. The problem of delamination can be solved.

Further, in the present embodiment, the final three-dimensional shape is formed while the photocurable resin 5 is confined in a certain space. A highly viscous resin can be used.

Next, FIG. 5 shows an example of a three-dimensional shape manufactured by using such a stereolithography method. FIG. 1 shows a rotary drive device for a micromachine such as a gear or a micromotor, and the rotary drive device 50 includes a shaft 51.
And a rotating body 52 rotatable therearound, and a retaining portion 53 of the rotating body 52 formed at the upper end of the shaft 51.

In this case, the rotating body 52 is completely separated from the base 55. Such shaping is possible with the optical shaping method according to the present invention because, as described above, when a laser beam is applied to the inside of a liquid photocurable resin, only the focal portion of the laser beam can be cured. It is.

On the other hand, when a similar rotary drive device is manufactured using a conventional optical forming method based on a free liquid surface method or a liquid surface regulation method, only the points inside the photocurable resin which are distant from the liquid surface are exposed. Cannot be cured, so as shown in FIG.
A stay 56 is required below the rotating body 52. By cutting the stay 56, a rotary drive device 50 'is obtained, but this cutting is not an easy operation.

On the other hand, in the optical shaping method according to the present invention, such a cutting operation is not required, and the rotary drive device for a micromachine can be manufactured at low cost in a short time.

The rotary drive device for a micromachine can be manufactured by a semiconductor fine processing technology such as thin film formation or etching, which is already known as a micromachine manufacturing technology. The structure is limited, and the cost and time are longer than those of the stereolithography method according to the present invention.

In the above embodiment, the laser beam L
An example is shown in which a beam moving mechanism 10 that moves a laser beam L from the viewpoint of emphasizing high speed is used as a focus moving unit that moves the focal point F in the X, Y, and Z axis directions inside the photocurable resin 5. However, application of the present invention is not limited to this.

A stage moving mechanism for moving the stage 6 with the laser beam L fixed may be adopted. Alternatively, by employing both the beam moving mechanism 10 and the stage moving mechanism, for example,
The X and Y axis directions may be moved by the beam moving mechanism 10, and the Z axis direction may be moved by the stage moving mechanism.

The movable device manufactured by using the optical shaping method according to the present invention is not limited to a rotary drive device as shown in FIG. 5, but a sliding device as shown in FIG. There may be.

In FIG. 7, this sliding device 60 is a linear mechanism for a micromachine, for example, a base 61 in which a V-shaped groove 61a is formed, and a cross section slidably disposed in the groove 61a. And a substantially V-shaped slider 62.

In this case, the slider 62 is completely separated from the base 61. Such molding is possible by the optical shaping method according to the present invention, as in the case of the rotary drive device 50 described above, when a laser beam is applied to the inside of a liquid photocurable resin, only the focal point of the laser beam is irradiated. This is because it is possible to cure

Further, according to the stereolithography method of the present invention,
It is also possible to produce a chain structure as shown in FIG. The chain structure 70 includes a plurality of chain members 71, 72, 7
3, 74, etc. Each chain member can freely move in a state where the adjacent chain members are engaged with each other.

Further, the stereolithography method according to the present invention can be applied to other than a micromachine. In this case,
When a three-dimensional shape is cured and formed inside the photocurable resin, the space containing the photocurable resin may be gradually expanded while replenishing the photocurable resin into the space.

This will be described with reference to FIG. 2. When the spacers 12 and 13 are gradually moved in a direction away from each other,
Alternatively, the lid 14 is gradually moved in a direction away from the base 11 and the base 11, the spacers 12, 13
The laser beam L may be applied to the space surrounded by the lid 14 while replenishing the photocurable resin 5 into the space.

In this manner, a relatively large movable device can be manufactured by the stereolithography method according to the present invention.

[0061]

As described in detail above, according to the present invention,
Since only the focal portion of the beam has the energy intensity necessary for curing the photocurable resin, it is possible to cure only the focal portion of the beam inside the photocurable resin,
As a result, the problem of peeling of the cured layer can be solved, the processing resolution can be further improved, and a highly viscous material can be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical modeling apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a photo-curing resin portion mounted on a stage of the optical shaping apparatus (FIG. 1).

FIG. 3 is a diagram for explaining the principle of an optical modeling method performed by the optical modeling apparatus (FIG. 1).

FIG. 4 is a view for explaining the principle of a conventional stereolithography method and corresponds to FIG. 3 of the present invention.

FIG. 5 is a view showing a rotation drive device for a micro machine manufactured by a stereolithography method.

FIG. 6 is a view showing a production example of a rotation drive device for a micromachine by a conventional stereolithography method.

FIG. 7 is a view showing a production example of a sliding device for a micromachine produced by an optical molding method.

FIG. 8 is a view showing a production example of a chain structure produced by a stereolithography method.

FIG. 9 is a view for explaining a free liquid level method which is a conventional stereolithography method.

FIG. 10 is a view for explaining a free liquid surface method which is a conventional stereolithography method.

FIG. 11 is a view for explaining a liquid surface regulation method which is a conventional stereolithography processing method.

FIG. 12 is a view for explaining a liquid surface regulation method which is a conventional stereolithography method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stereolithography apparatus 2 Laser oscillator 3 Beam expander 4 Lens 5 Photocurable resin 5a Liquid surface 6 Stage 10 Beam moving mechanism 20 Three-dimensional shape 50 Micromachine rotation drive device 52 Rotating body 60 Micromachine sliding device 62 Slider 70 Chain shape Structure 71-74 Chain member L Laser beam A Irradiation area E Energy intensity ε ₀ Critical intensity α Open angle

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[Procedure amendment]

[Submission date] January 29, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 9

FIG. 10

FIG. 11

FIG.

Claims (5)

[Claims] 1. An optical shaping method for irradiating a liquid photocurable resin with light to cure the photocurable resin into a desired shape, wherein the liquid photocurable resin is confined in a certain space, By condensing after widening the width of the light beam to be irradiated, only the focal point of the light beam is set to the energy intensity necessary for curing the photocurable resin, and from this state, the light beam is placed inside the photocurable resin. A stereolithography method characterized by irradiating. 2. A movable device comprising a movable member, wherein the movable device is manufactured using the stereolithography method according to claim 1. 3. The movable device according to claim 2, wherein the movable device is a movable device for a micro machine, and the movable member is a rotating body or a sliding body. 4. An optical shaping apparatus for irradiating a liquid photo-curable resin with light to cure the photo-curable resin into a desired shape, comprising: a laser oscillator for emitting a laser beam; A lens for condensing the laser beam emitted from the laser, a stage which is confined in a certain space, and on which a liquid photocurable resin to be irradiated with the laser beam condensed by the lens is mounted; and The laser beam emitted from the laser oscillator is disposed between the oscillator and the lens, and the beam width of the laser beam emitted from the laser oscillator is increased so that only the focal point of the laser beam condensed by the lens becomes the energy required for curing the photocurable resin. A beam expander for increasing the intensity of the laser beam, and a focal point moving means for moving the focal point of the laser beam inside the photocurable resin. Processing equipment. 5. An optical shaping process according to claim 4, wherein said focus moving means comprises at least one of a beam moving mechanism for moving a beam and a stage moving mechanism for moving a stage. apparatus.