JP3988964B2 - Method for forming movable device for micromachine by stereolithography - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a movable device for a micromachine by an optical modeling method.
[0002]
[Prior art and problems]
As a processing method for machine parts, an optical modeling processing method has been put into practical use. In general, the stereolithography method is a processing method for irradiating a photocurable resin in a liquid state with light 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 advanced research and development for practical application of this stereolithography processing method as a fundamental technology of a micromachine that is expected to be applied to the medical field.
[0004]
In order to apply the stereolithography method to three-dimensional micromachining for a micromachine, it is necessary to make the minimum curing unit of the photocurable resin, which is the processing resolution, as small as possible.
[0005]
By the way, in the conventional stereolithography processing method, there is a method called a free liquid level method as shown in FIG. 9 and FIG.
In the example shown in FIG. 9, first, a liquid photo-curing resin 110 is put in such an amount 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 cured and solidified (see the cured layer 1 in FIG. 1A).
[0006]
Next, the liquid photocurable resin 110 is added to increase the liquid level so that the upper surface of the cured layer 1 is thinly covered with the photocurable resin 110. From this state, when the liquid surface is irradiated with light L, the photo-curing resin is cured, and a second cured layer 2 is formed on the first cured layer 1 (see FIG. 9B). Hereinafter, by repeating the same operation, a three-dimensional shape in which a large number of layers are stacked is formed.
[0007]
Further, in the structure shown in FIG. 10, unlike FIG. 9, a hardened layer is formed one after another on the stage 120 that can be raised and lowered. That is, first, a certain amount of the liquid photocurable resin 110 is put in 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. Like that.
[0008]
From this state, the first hardened layer 1 is formed by irradiating the liquid surface with light L and curing it (see FIG. 10A). Next, the stage 120 is lowered by one stage to form a thin layer of the liquid photo-curing resin 110 between the cured layer 1 and the liquid surface, and from this state, the liquid surface is irradiated with light L, A second hardened layer 2 is formed (see FIG. 5B). Thereafter, by repeating the same operation, a three-dimensional shape composed of a number of layers is formed.
[0009]
In such a free liquid level method, the thinner the liquid layer, the harder it is to have a uniform thickness due to the effect of surface tension, making it easier to control the thickness of the cured layer. However, there is a problem that the resolution cannot be increased. Further, since the viscosity of the liquid photo-curing resin is generally high, there is a problem that it takes time until the liquid level is stabilized.
[0010]
On the other hand, the conventional stereolithography method includes a method called a liquid level regulation method as shown in FIGS.
In what is shown in FIG. 11, first, a certain amount of liquid photo-curing resin 110 is put in a container. From this state, the vertically movable stage 130 having translucency is moved downward so that a thin layer of the liquid photocurable resin 110 is formed between the stage lower surface 130 a and the container bottom surface 140.
[0011]
Next, the cured layer 1 of the first layer is formed by irradiating the photocurable resin 110 with light L from above through the stage 130 and curing it (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 1, and from this state, the photocurable resin 110 is irradiated with light L. Then, the second hardened layer 2 is formed (see FIG. 5B). Thereafter, by repeating the same operation, a three-dimensional shape composed of a large number of layers is formed.
[0012]
In the case shown 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 placed in the container, and the stage 160 is moved downward, so that the liquid photocurable resin 110 is placed between the stage lower surface 160a and the container bottom surface 170. Form a thin layer.
[0013]
From this state, the cured layer 1 of the first layer is formed by irradiating the light curable resin 110 with light L from below through the transparent window 150 and curing it (see FIG. 12A). Next, the stage 160 is moved up by one stage together with the hardened layer 1 to form a thin layer of the liquid photocurable resin 110 between the hardened layer 1 and the bottom surface 170 of the container. From this state, the liquid is passed through the transparent window 150. By irradiating the light curable resin 110 with light L, the second cured layer 2 is formed. Thereafter, by repeating the same operation, a three-dimensional shape composed of a large number of layers is formed (see FIG. 5B).
[0014]
In such a liquid level 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 layer of the cured layer, and the resolution can be increased to some extent. At the same time, there is no need to wait for the liquid level to stabilize, so that the processing can be performed quickly. On the other hand, when the stage is raised, the hardened layer is completely removed from the stage lower surface 130a or the transparent window 150. Therefore, it is necessary to apply a release agent on the lower surface of the stage or the transparent window, or to perform a treatment such as Teflon coating.
[0015]
However, even when such treatment is performed, the interface of the hardened layer does not always peel completely from the lower surface of the stage or the transparent window, and peeling occurs inside the hardened layer, resulting in deformation or breakage in the three-dimensional shape. There is.
[0016]
In addition, in this liquid level regulation method, in order to further improve the processing resolution, it is necessary to make the moving distance of the stage as small as possible. However, if the moving distance of the stage becomes too small, it will be cured even if the stage is moved. There are cases where the layer is not elastically deformed and the interface of the hardened layer is not peeled off. Therefore, the processing resolution is limited even by the liquid level regulation method.
[0017]
The present invention has been made in view of such a conventional situation, and an object of the present invention is to solve the problem of peeling of a hardened layer and to further improve the processing resolution of a movable device for a micromachine by an optical modeling processing method. It is to provide a forming method.
[0018]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for forming a movable device for a micromachine using a stereolithography method in which a photocurable resin is cured by irradiating a liquid photocurable resin with light. This is a method for forming a movable device for a micromachine inside. In this method, a liquid photo-curing resin is confined in a fixed space, a light beam is irradiated inside the photo-curing resin, and only the focal point of the light beam is set to an energy intensity necessary for curing the photo-curing resin. In this state, the light beam is scanned inside the light curable resin to form the first member inside the light curable resin without using the lifting stage , and the light beam is irradiated inside the light curable resin. In addition, the light beam is scanned with a gap between the first member and the first member inside the photo-curing resin in a state where only the focal point of the light beam is set to the energy intensity necessary for curing the photo-curing resin. , inside the photocurable resin formed without using and elevation stage without being fastened to the second member relatively movable to the first member relative to the first member, these relatively movably It is characterized by comprising the step of forming the movable device from the first and second members such.
[0019]
According to a second aspect of the present invention, there is provided a method for forming a movable device for a micromachine according to the first aspect, wherein the first member is a shaft and the second member is a rotating body that is rotatable around the shaft. Yes.
[0020]
According to a third aspect of the present invention, there is provided a method for forming a movable device for a micromachine according to the first aspect, wherein the first member is a base and the second member is a slider that can slide on the base.
[0021]
According to a fourth aspect of the present invention, there is provided a method for forming a movable device for a micromachine according to the first aspect, wherein the first and second members are chain members and are connected to each other to form a chain structure. It is a feature.
[0022]
According to the stereolithography method according to the present invention, the light beam applied to the photo-curing resin has an energy intensity necessary for curing the photo-curing resin only at the focal point of the light beam.
[0023]
For this reason, when irradiating a light photocurable resin confined in a certain space with a light beam, the focal point of the light beam may be arranged in a portion to be cured in the photocurable resin. In the photo-curing resin, only the focal portion of the light beam is cured, and no curing occurs in the other irradiated portions of the light beam. Therefore, if the focal point of the light beam is moved inside the photo-curing resin, a desired three-dimensional shape can be obtained.
[0024]
As described above, in the present invention, in order to form a desired three-dimensional shape, the focus of the light beam has only to be moved inside the photo-curing resin, so that an elevating stage is not required, and as a result, there is a problem of peeling of the cured layer. Can be eliminated.
[0025]
In addition, since only the focal portion of the light beam is cured when the light beam is irradiated, the processing resolution can be greatly improved. As a result, it is possible to form a micro movable device for a micromachine including the first and second members that can move relative to each other.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described 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 the figure, this stereolithography processing apparatus 1 has passed through a laser oscillator 2, a beam expander 3 for expanding the beam width of the laser beam L emitted from the laser oscillator 2, and the beam expander 3. The lens 4 is mainly composed of a lens 4 for condensing the laser beam L and a stage 6 on which a photocurable resin 5 irradiated with the laser beam L condensed by the lens 4 is placed.
[0027]
In front of the laser oscillator 2, a shutter 7 and a filter 8 for adjusting the amount of light are arranged. A mirror (or prism) 9 for guiding the laser beam L emitted from the laser oscillator 2 to the beam expander 3 side is provided.
[0028]
Between the beam expander 3 and the lens 4, a beam moving mechanism 10 such as a galvano mirror for moving the laser beam L in the X, Y, and Z axis directions at high speed is provided. Here, the horizontal direction in the figure is the X-axis direction, the vertical direction on the paper is the Y-axis direction, and the vertical direction in the figure is the Z-axis direction. The shutter 7 and the beam moving mechanism 10 are controlled by a control signal from a control unit (not shown).
[0029]
As shown in FIG. 2, the liquid photocurable resin 5 is accommodated in a fixed space formed by a translucent base 11, spacers 12 and 13, and a lid body 14.
[0030]
Next, an optical modeling method using the optical modeling apparatus according to this embodiment will be described.
The laser beam L emitted from the laser oscillator 2 passes 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 incident is changed to a thick parallel light beam after emission.
[0031]
The laser beam L emitted from the beam expander 3 enters the lens 4 through the beam moving mechanism 10, is condensed by the lens 4, and enters the photo-curing resin 5 on the stage 6 (see FIG. 2).
[0032]
At this time, since the beam width is expanded by the beam expander 3, the opening angle α of the laser beam L incident on the photo-curing resin 5 is large, for example, an obtuse angle, as shown in FIG. Thus, when the energy intensity E of the laser beam L is taken on the vertical axis (axis taken in the depth direction of the photocurable resin 5), only the portion of the focal point F of the laser beam L is used to cure the liquid photocurable resin 5. The necessary energy intensity (critical intensity) ε ₀ has been reached, and the energy intensity of the other irradiation region A of the laser beam L is smaller than ε ₀ .
[0033]
That is, in the photo-curing 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 the other irradiation region A is not cured.
[0034]
Therefore, in order to obtain a desired three-dimensional shape from the photo-curing resin 5, the laser beam L is placed inside the photo-curing resin 5 so that the focal point F of the laser beam L is located in the liquid, that is, the back side of the liquid surface 5a. In addition to irradiating, the laser beam L may be 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. As a result, as shown in FIG. 2, the desired three-dimensional shape 20 is cured and formed inside the photocurable resin 5.
[0035]
In the conventional stereolithography method, as shown in FIG. 4, when the opening angle of the laser beam L ′ used is small, and the energy intensity E of the laser beam L ′ is taken on the vertical axis as in FIG. The liquid surface 5a portion of the photo-curing resin 5 reaches the critical strength ε ₀ , and the entire in-liquid irradiation area A ′ of the laser beam L ′ is in an energy state necessary for curing the photo-curing resin 5. Therefore, the photo-curing resin 5 is cured over the entire irradiation area A ′ of the laser beam L ′. For this reason, in the conventional method, processing resolution is low.
[0036]
On the other hand, in the stereolithography processing 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 dramatically improved. Thereby, a micro structure for a micro machine can be easily manufactured.
[0037]
In the present embodiment, when a desired three-dimensional shape is formed, the laser beam L is irradiated inside the photocurable resin 5 confined in a certain space, and the focal point F of the laser beam L is photocured. Since it is only necessary to move the inside of the resin 5 appropriately, it is not necessary to move the cured layer of the photo-curing resin 5 together with the lifting stage, thereby eliminating the problem of peeling of the cured layer accompanying the movement of the lifting stage.
[0038]
Furthermore, in this embodiment, since the final three-dimensional shape is formed while the photo-curing resin 5 is confined in a certain space, it is hardly affected by the viscosity of the photo-curing resin 5 and is highly effective as a photo-curing resin. A viscous material can be used.
[0039]
Next, FIG. 5 shows an example of a three-dimensional shape manufactured using such an optical modeling method.
What is shown in the figure is a micromachine rotary drive device such as a gear or a micromotor. The rotary drive device 50 includes a shaft 51, a rotating body 52 that can rotate around the shaft 51, and an upper end of the shaft 51. It is comprised from the formed retaining part 53 of the rotary body 52.
[0040]
In this case, the rotating body 52 is completely separated from the base 55. Such molding is possible with the optical modeling method according to the present invention because, as described above, only the focal portion of the laser beam can be cured when the laser beam is irradiated inside the liquid photo-curing resin. It is.
[0041]
On the other hand, when a similar rotational drive device is manufactured using the conventional free-formation method or the stereolithography method using the liquid-level regulation method, only the internal points away from the liquid surface of the photo-curing resin are cured. Therefore, as shown in FIG. 6, a stay 56 is required below the rotating body 52. By cutting the stay 56, the rotational drive device 50 'can be obtained, but this cutting is not an easy task.
[0042]
On the other hand, in the stereolithography processing method according to the present invention, such a cutting operation becomes unnecessary, and it becomes possible to manufacture a micromachine rotary drive device at a low cost in a short time.
[0043]
Note that this micromachine rotary drive device can be manufactured by a semiconductor microfabrication technique such as thin film formation or etching, which is already known as a micromachine manufacturing technique. In addition, cost and time are required as compared with the optical modeling method according to the present invention.
[0044]
Further, in the above-described embodiment, the focal point moving means for moving the focal point F of the laser beam L in the X, Y, and Z axis directions inside the photocurable resin 5 is a beam that moves the laser beam L from the viewpoint of emphasizing high speed. Although the example using the moving mechanism 10 was shown, application of the present invention is not limited to this.
[0045]
You may make it employ | adopt the stage moving mechanism which moves the stage 6 in the state which fixed the laser beam L. FIG. 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.
[0046]
Further, the movable device manufactured by using the optical modeling method according to the present invention is not limited to the rotary drive device as shown in FIG. 5, and may be a sliding device as shown in FIG. 7. Good.
[0047]
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 substantially V-shaped cross section disposed slidably in the groove 61a. The slider 62 has a shape.
[0048]
In this case, the slider 62 is completely separated from the base 61. As in the case of the above-described rotational drive device 50, such molding can be performed by the optical modeling method according to the present invention only when the laser beam is irradiated inside the liquid photo-curing resin, only the focal portion of the laser beam. This is because it can be cured.
[0049]
Furthermore, according to the stereolithography method of the present invention, a chain structure as shown in FIG. 8 can be manufactured. The chain structure 70 includes a plurality of chain members 71, 72, 73, 74, and the like. Each chain member can move freely in a state where adjacent chain members are engaged with each other.
[0050]
【The invention's effect】
As described in detail above, according to the present invention, since only the focal point of the beam has the energy intensity necessary for curing the photo-curing resin, only the focal point of the beam can be cured inside the photo-curing resin. As a result, the problem of peeling of the hardened layer can be solved, the processing resolution can be further improved, and a highly viscous material can be used, so that the first and second members that move relative to each other can be used. This makes it possible to form a movable device for a micromachine.
[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 placed on the stage of the optical modeling apparatus (FIG. 1).
FIG. 3 is a diagram for explaining the principle of an optical modeling processing method executed by the optical modeling processing apparatus (FIG. 1).
FIG. 4 is a view for explaining the principle of a conventional stereolithography method, corresponding to FIG. 3 of the present invention.
FIG. 5 is a diagram showing a micromachine rotary drive device manufactured by an optical modeling method.
FIG. 6 is a view showing an example of manufacturing a micromachine rotary drive device by a conventional stereolithography method.
FIG. 7 is a view showing a manufacturing example of a sliding device for a micromachine manufactured by a stereolithography method.
FIG. 8 is a view showing a manufacturing example of a chain structure manufactured by an optical modeling method.
FIG. 9 is a view for explaining a free liquid level method that is a conventional stereolithography method.
FIG. 10 is a view for explaining a free liquid level method which is a conventional stereolithography method.
FIG. 11 is a diagram for explaining a liquid level regulation method, which is a conventional stereolithography method.
FIG. 12 is a diagram for explaining a liquid level regulation method, which is a conventional stereolithography method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical modeling processing apparatus 2 Laser oscillator 3 Beam expander 4 Lens 5 Photocurable resin 5a Liquid level 6 Stage 10 Beam moving mechanism 20 Three-dimensional shape 50 Micromachine rotary drive device 52 Rotating body 60 Micromachine slide device 62 Slider 70 Chain shape Structures 71 to 74 Chain member L Laser beam A Irradiation area E Energy intensity ε ₀ Critical strength α Opening angle

Claims (4)

A liquid light curable resin (5) is irradiated with light using a stereolithography processing method for curing the photocurable resin (5), a micromachine for the mobile devices within the photocurable resin (5) (50, 60, 70 )
The liquid photo-curing resin (5) is confined in a certain space,
The light beam (L) is irradiated inside the photo-curing resin (5) , and only the focal point (F) of the light beam (L) is set to the energy intensity necessary for curing the photo-curing resin (5). by scanning within the beam (L) a photocurable resin (5), without using the elevation stage, formed inside the first member (51,61,72,74) of a photocurable resin (5) And
The light beam (L) is irradiated inside the photo-curing resin (5) , and only the focal point (F) of the light beam (L) is set to the energy intensity necessary for curing the photo-curing resin (5). By scanning the beam (L) with a gap between the first member (51, 61, 72, 74) inside the photo-curing resin (5) , the inside of the photo-curing resin (5) . the first member without being fixed to (51,61,72,74) the first member (51,61,72,74) movable relative to a second member (52,62,71, 73) is formed without using an elevating stage , and the movable device (50, 60, 70 ) is formed from the first and second members (51, 61, 72, 74; 52, 62, 71, 73) that can move relative to each other. Formed )
A method for forming a movable device for a micromachine. In claim 1,
The first member is a shaft (51) , and the second member is a rotating body (52) rotatable around the shaft (51) .
A method for forming a movable device for a micromachine. In claim 1,
The first member is a base (61) , and the second member is a slider (62) that can slide on the base (61) .
A method for forming a movable device for a micromachine. In claim 1,
The first and second members are chain members (71, 72, 73, 74) that are connected to each other to form a chain structure,
A method for forming a movable device for a micromachine.

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