JPWO2012111655A1 - Stereolithography method and stereolithography apparatus - Google Patents

Abstract

The present invention provides an optical modeling method and the like in which a jig such as a mold is not required, the degree of freedom of a product shape is high, and a process is simplified. An optical modeling method includes storing a reaction solution that gels by irradiating light in a reaction vessel, and placing an optical element that emits light at a tip under the surface of the reaction solution. The reaction is induced by irradiating the reaction solution with the optical element while moving the two and the three-dimensional object made of a gel-like body in the reaction container. [Selection] Figure 1

Description

  The present invention relates to an optical modeling method and an optical modeling apparatus in which a reaction solution is irradiated with light to mold a high-strength gel.

  The gel refers to a polymer having a three-dimensional network structure that is insoluble in a solvent and a swollen body thereof. A swollen gel that has absorbed a large amount of solvent is an intermediate material form between a solid and a liquid, and changes from a viscous liquid to a fairly hard solid depending on its chemical composition and various factors. It exists in a special form that is different from the general state of matter.

In addition, high-strength gels that improve the mechanical strength of such gels have been developed.
Such high-strength gels can be used in various industrial applications such as artificial blood vessels, custom-made contact lenses, various buffer materials, and scaffolds for cell growth for regenerative medicine.

However, conventional high-strength gels require a complicated process, such as placing the liquid as a material into a mold, hardening it, impregnating the primary processed product taken out of the mold with the liquid, and then curing it in the mold. And it was cumbersome.
Moreover, in order to manufacture a wide variety of high-strength gel materials by such a manufacturing method, a mold is required for each shape, and the manufacturing time, manufacturing cost, and man-hours required for management are enormous.
Furthermore, it is necessary to consider the production conditions under which the high-strength gel can be extracted from the mold, and there is a problem that the shape that can be produced is limited.

On the other hand, in recent years, liquids that polymerize and gel when irradiated with light have been developed.
For example, Patent Documents 1 and 2 describe a method for producing a polymer gel in which a liquid that is polymerized by a UV laser is placed in a mold frame and irradiated with the UV laser.

JP 2009-185156 A JP 2009-298971 A

However, the technique of Patent Document 1 described above also has the same problem as the existing technique in that a mold or jig for molding is necessary and the shape of the product is limited.
An object of the present invention is to provide an optical modeling method and an optical modeling apparatus that do not require a jig such as a mold, have a high degree of freedom in product shape, and have a simplified process.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 stores a reaction solution that gels when irradiated with light in a reaction vessel, and puts an optical element whose tip emits light below the surface of the reaction solution. It is an optical modeling method characterized in that a reaction is induced by irradiating the reaction solution with the optical element while moving relative to a reaction container to form a three-dimensional object made of a gel-like body in the reaction container.
According to this, a high-strength gel product having a free shape can be manufactured in a short time without preparing a mold, a jig and the like.
In addition, it is not necessary to remove the mold from the mold, and even a shape that cannot be self-supported in the air can be manufactured, so that the degree of freedom of the product shape is improved.

The invention according to claim 2 is the optical modeling method according to claim 1, wherein the optical element is an optical element that generates near-field light from a tip portion.
According to this, by generating near-field light, it is possible to prevent light energy from diffusing into the reaction solution and to cause a chemical reaction only in the vicinity of the tip of the optical element.

The invention according to claim 3 is the optical modeling method according to claim 1, wherein the optical element induces a reaction by two-photon excitation by light irradiation from a tip portion.
In general, most of the light energy radiated from the tip of an optical element such as an optical fiber is consumed for the reaction of the reaction solution, but a part is diffused and accumulated in the reaction solution. When the three-dimensional modeling work takes a long time, the light energy accumulated in the reaction liquid reaches an energy amount sufficient to start the reaction, and there is a concern that a reaction may occur at a position other than a predetermined position.
On the other hand, since the light energy distribution in the optical element cross section is a Gaussian distribution, the center portion of the distribution has the strongest energy. By utilizing this phenomenon and making strong light incident on the optical element, it is possible to generate two-photon excitation only in the central portion of the optical element.
Since the region where two-photon excitation occurs is near the top of the Gaussian distribution, the spot diameter can be reduced.
In addition, since this region has a wavelength that is half that of the light incident on the optical element, it is possible to cause a chemical reaction only near the tip of the optical element by preparing a reaction solution that reacts to this half wavelength.

According to a fourth aspect of the present invention, in the reaction container, an insertion depth of the optical element into the reaction solution is within a predetermined range according to a relative height between the optical element and the reaction container. The liquid modeling method according to any one of claims 1 to 3, wherein a liquid level of the reaction liquid is changed.
According to this, it is possible to reduce the depth at which the optical element is put into the reaction solution, shorten the protruding length of the optical element tip from the holder that holds the optical element, and ensure rigidity. It becomes easy. For this reason, it is possible to prevent the moving optical element from being deformed by receiving a resistance force from the high-viscosity reaction liquid and perform accurate molding.

The invention according to claim 5 is characterized in that the reaction solution has a specific gravity substantially similar to that of the gel-like body formed by irradiation with light. The optical modeling method according to Item 1.
In general, a high-strength gel produced by reaction of a reaction solution contains a large amount of moisture, and it is difficult to maintain its own shape in the air. For this reason, when the shape is sequentially generated in the air, it is very difficult to continue the modeling because it is deformed by its own weight.
On the other hand, according to the present invention, by making the specific gravity of the reaction liquid and the specific gravity of the gel-like body the same, the shape of the gel-like body can be fixed in the reaction liquid.
In this case, the viscosity of the reaction liquid is given to some extent, thereby suppressing the influence of the reaction liquid flow and vortex generated when the optical element moves in the reaction liquid, and fixing the position of the gel-like body. Can do.

The invention according to claim 6 is characterized in that the reaction vessel includes means for extracting the reaction solution and injecting another substitution solution and a shape retention solution. The optical modeling method according to Item 1.
From the characteristics of the gel, it is possible to replace the liquid inside by changing the solution in which the gel is immersed, and to add other characteristics to the gel. Using this principle, after forming one kind of gel in the reaction container, the reaction liquid in the container is replaced with a replacement liquid using a pump, whereby the liquid inside the gel can be replaced.
Moreover, it becomes possible to hold | maintain a gel for a long time by inject | pouring a shape retention liquid in a reaction container.

  According to a seventh aspect of the present invention, there is provided a reaction vessel that stores a reaction solution that gels when irradiated with light, an optical element that emits light at a tip, and a reaction solution in which the tip of the optical element is in the reaction vessel. An optical modeling apparatus comprising: a relative movement unit configured to relatively move the optical element and the reaction container in a state of being placed inside.

  The invention according to claim 8 is the stereolithography apparatus according to claim 7, wherein the relative movement device includes a three-axis robot capable of driving the optical element in three orthogonal axes.

  The invention according to claim 9 is the stereolithography apparatus according to claim 7 or 8, wherein the optical element is an optical element that generates near-field light from a tip portion.

  The invention according to claim 10 is the optical shaping apparatus according to claim 7 or claim 8, wherein the optical element induces a reaction by two-photon excitation by light irradiation from a tip portion.

  According to an eleventh aspect of the present invention, there is provided a reserve tank provided outside the reaction vessel, the reaction liquid in the reaction vessel being extracted and stored in the reserve tank, and the reaction stored in the reserve tank. A pump for returning the liquid into the reaction container, and the insertion depth of the optical element into the reaction liquid is within a predetermined range by driving the pump according to the relative height between the optical element and the reaction container. 11. The stereolithography apparatus according to claim 7, further comprising: a control unit that changes a liquid level height of the reaction liquid in the reaction container so as to satisfy is there.

  The invention according to claim 12 is characterized in that the reaction solution has a specific gravity substantially the same as that of the gel-like body formed by light irradiation. The stereolithography apparatus according to item 1.

  The invention according to claim 13 is characterized in that the reaction vessel includes means for extracting the reaction solution and injecting another replacement solution and a shape retention solution. The stereolithography apparatus according to item 1.

  As described above, according to the present invention, there are provided a stereolithography method and a stereolithography apparatus in which a jig such as a mold is unnecessary and the degree of freedom of a product shape is high and the process is simplified.

It is a typical external appearance perspective view of 1st Embodiment of the optical modeling apparatus to which this invention is applied. It is the II section enlarged view of Drawing 1, and is a figure showing the shape of the tip part of an optical fiber. It is a schematic diagram which shows the influence of the Karman vortex which arises when moving an optical fiber within a reaction liquid. It is a figure which shows the shape of the front-end | tip part of the optical fiber in 2nd Embodiment of the optical modeling apparatus to which this invention is applied, and distribution of optical energy. It is a figure which shows the structure of the reaction liquid tank in 3rd Embodiment of the optical modeling apparatus to which this invention is applied. It is a figure which shows the structure of the reaction liquid tank, substitution liquid tank, and shape retention liquid tank in 4th Embodiment of the optical modeling apparatus to which this invention is applied. It is a figure which shows the shape of the front-end | tip part of the optical fiber in 5th Embodiment of the optical modeling apparatus to which this invention is applied.

Hereinafter, first to fourth embodiments of an optical modeling method and an optical modeling apparatus to which the present invention is applied will be described in detail with reference to the drawings.
The stereolithography method and stereolithography apparatus of each embodiment can form, for example, artificial blood vessels made of high-strength gels, custom-made contact lenses, various buffer materials, cell growth scaffolds for regenerative medicine, etc. The workpiece to be machined is not limited to these, and can be changed as appropriate.

<First Embodiment>
FIG. 1 is a schematic external perspective view of a first embodiment of an optical modeling apparatus to which the present invention is applied.
As shown in FIG. 1, the optical modeling apparatus 1 includes a reaction vessel 10, a laser oscillator 20, a triaxial robot 30, and the like.

The reaction container 10 is a container that stores a reaction liquid that is gelled by laser light and gels the reaction liquid inside.
Moreover, the reaction container 10 can be removed from the optical modeling apparatus 1 and can be used for storing and moving a product made of high-strength gel.

The laser oscillator 20 generates UV laser light used for gelation of the reaction solution.
The UV laser light output from the laser oscillator 20 is introduced into the reaction vessel 10 via the optical fiber 21.
The optical fiber 21 is movable in the orthogonal three-axis direction within the reaction vessel 10 by supporting the holder 22 holding the vicinity of the tip 21a thereof by the three-axis robot 30.

FIG. 2 is an enlarged view of part II in FIG.
The tip portion 21a of the optical fiber 21 is formed in a tapered shape, and the protruding end surface is formed in a substantially flat shape. In the optical fiber 21, the reaction solution is gelled by near-field light in the region R1 in the vicinity of the protruding end of the tip 21a.
The optical fiber 21 is configured by covering the periphery of the core 21b with a metal film 21c generated by sputtering or the like in order to reflect light.
The optical fiber 21 is a so-called sharpened fiber in which the diameter of the opening provided on the end face of the distal end portion 21a is smaller than the wavelength of ultraviolet rays.

The triaxial robot 30 includes a base 31, a tower 32, an arm 33, a holder holding unit 34, and the like.
The base portion 31 is a fixed portion in which relative movement with respect to the reaction vessel 10 is restricted, and includes a rail portion that guides the tower 32 in the horizontal direction (X-axis direction).

The tower 32 protrudes from the base portion 31 in the vertical direction (Z-axis direction) and is movable along the rail portion of the base portion 31 in the X-axis direction.
The tower 32 includes a rail portion that guides the arm 33 in the Z-axis direction.

The arm 33 protrudes in the horizontal direction (Y axis direction) perpendicular to the X axis with respect to the tower 32 and is movable in the Z axis direction along the rail portion of the tower 32.
The arm 33 includes a rail portion that guides the holder holding portion 34 in the Y-axis direction.

The holder holding part 34 is a part to which the above-described holder 22 is attached.
The holder holding part 34 is movable in the Y-axis direction along the rail part of the arm 33.
With the configuration described above, the distal end portion 21a of the optical fiber 21 attached to the holder support portion 34 via the holder 22 can be moved relative to the reaction vessel 10 in the XYZ orthogonal three-axis directions. Yes.
When a product made of high-strength gel is molded, the path of the tip 21a is set in advance by, for example, a known numerical value input.

  In the first embodiment, the reaction solution is stored in the reaction vessel 10, and the tip 21 a of the optical fiber 21 is placed (immersed) in the reaction vessel 10 while irradiating the tip 21 a with the UV laser, The high-strength gel product is molded by moving the part 21a along the set path by the three-axis robot 30.

FIG. 3 is a schematic diagram showing the influence of Karman vortices generated when the optical fiber is moved in the reaction solution.
When the viscosity of the reaction solution is low, the reaction solution flows when the optical fiber 21 is moved, and it may be difficult to maintain the shape and position of the product W. In particular, when the Karman vortex V is generated, such a problem becomes remarkable.
Therefore, in the first embodiment, the generation of vortices is suppressed by sufficiently increasing the viscosity of the reaction solution.
Moreover, the product can be fixed in the reaction solution by using a reaction solution having substantially the same specific gravity as the high-strength gel (product W) after photomolding.

As the reaction solution, those described below can be used.
The chemicals shown in the following 1st gel are mixed, then cross-linked with UV light, cured and pulverized.
Then, the chemical shown in the 2nd gel is mixed with the pulverized 1st gel to complete the solution.

<1st gel>
Monomer NaAMPS 1mol / l (2-acrylamido-2-methyl-1-propanesulfonic acid, sodium salt, 50wt% solution in water)
Crosslinker MBAA 4mol% (N, N'-methylenebis- (acrylamide))
Photoinitiator α-keto 0.1mol% (α-keto glutaric acid)

<2nd gel>
Monomer DMAAm 2mol / l (N, N-dimethylacrylamide)
Crosslinker MBAA 0.02mol /% (N, N'-methylenebis- (acrylamide))
Photoinitiator α-keto 0.1mol% (α-keto glutaric acid)

According to the first embodiment described above, the following effects can be obtained.
(1) A free-form high-strength gel product can be produced in a short time without preparing a mold, a jig or the like.
In addition, it is not necessary to remove the mold from the mold, and even a shape that cannot be self-supported in the air can be manufactured, so that the degree of freedom of the product shape is improved.
(2) By gelling the reaction solution with near-field light, it is possible to prevent the light energy from diffusing into the reaction solution and to cause a chemical reaction only in the vicinity of the tip of the optical fiber.
(3) By making the specific gravity of the reaction solution substantially the same as that of the gel after molding and increasing the viscosity, the product can be fixed in the reaction solution, and accurate modeling becomes possible.

Second Embodiment
Next, a second embodiment of the optical modeling method and the optical modeling apparatus to which the present invention is applied will be described.
In each of the embodiments described below, portions that are substantially the same as those in the previous embodiment are denoted by the same reference numerals, description thereof is omitted, and differences are mainly described.

The second embodiment is characterized in that a reaction solution corresponding to a half wavelength of the laser oscillator 20 is used as the reaction solution, and gelation is performed by two-photon excitation.
FIG. 4 is a diagram showing the shape of the tip of the optical fiber and the distribution of light energy in the second embodiment. FIG. 4A shows the shape of the tip of the optical fiber, and FIG. 4B shows an enlarged view of part b of FIG. 4A and the distribution of light energy.

As shown in FIG. 4B, the two-photon excitation occurs only in the region R2 of the central portion of the optical fiber 21 where the optical energy peak has a Gaussian distribution. In the region R2 where the two-photon excitation occurs, the wavelength is ½ of the incident light to the optical fiber 21 and the light energy is doubled.
In this region R2, gelation of the reaction solution occurs.
On the other hand, in the region R3 where no other two-photon excitation occurs, the wavelength is the same as the incident light and the light energy is low.
In this region R3, the reaction solution does not gel.

In the second embodiment described above, the following effects can be obtained in addition to the effects substantially similar to the effects of the first embodiment described above.
Since the region where two-photon excitation occurs is near the top of the Gaussian distribution, the spot diameter can be reduced.
In addition, since this region has a wavelength half that of the light incident on the optical fiber, it is possible to cause a chemical reaction only in the vicinity of the tip of the optical fiber by preparing a reaction solution that reacts with this half wavelength.
Thus, even if the three-dimensional modeling work takes a long time, it is possible to prevent a portion that does not need to be gelled from reacting due to the energy accumulated in the reaction solution.

<Third Embodiment>
Next, a third embodiment of the optical modeling method and the optical modeling apparatus to which the present invention is applied will be described.
The third embodiment is characterized in that a reaction liquid tank is connected to the reaction vessel 10.
FIG. 5 is a diagram showing the configuration of the reaction liquid tank.
The reaction liquid tank T1 is connected to the reaction vessel 10 via a pipe line having a pump P1.

The pump P1 is driven in response to a command from a control device (not shown), can supply the reaction solution from the reaction solution tank T1 to the reaction vessel 10, and can extract the reaction solution from the reaction vessel 10 to the reaction solution tank T1. ing.
Here, the control device of the pump P1 operates in conjunction with the drive control device of the three-axis robot 30 so that the insertion depth d of the optical fiber 21 into the reaction solution is equal to or less than a predetermined value set in advance. The liquid level in the container 10 is adjusted.

In the second embodiment described above, the following effects can be obtained in addition to the effects substantially similar to the effects of the first embodiment described above.
It is possible to reduce the depth at which the optical fiber is put into the reaction liquid, and it is possible to prevent the moving optical fiber from being deformed due to a resistance force from the high-viscosity reaction liquid.

<Fourth embodiment>
Next, a fourth embodiment of the optical modeling method and the optical modeling apparatus to which the present invention is applied will be described.
The third embodiment is characterized in that a reaction liquid tank, a replacement liquid tank, and a shape retention liquid tank are connected to the reaction vessel 10.
FIG. 6 is a diagram showing the configuration of the reaction liquid tank and the like.

The reaction liquid tank T1, the substitution liquid tank T2, and the shape retention liquid tank T3 are connected to the reaction vessel 10 via pumps P1, P2, and P3 that can be driven independently.
Here, the replacement liquid is a liquid exchanged as a liquid inside the gel after gelation, and for example, ethylene glycol, ethanol, silicone oil, saline, or the like can be used.
After the reaction liquid is put into the reaction vessel 10 from the reaction liquid tank T1 and gelled, the liquid in the gel can be replaced by extracting the reaction liquid and injecting the replacement liquid.
The shape retention liquid is a liquid for retaining the gel for a long time, and for example, ethylene glycol, ethanol, silicone oil, saline, pure water, or the like can be used.

According to the fourth embodiment described above, the following effects can be obtained in addition to the effects substantially similar to those of the first embodiment described above.
From the characteristics of the gel, it is possible to replace the liquid inside by changing the solution in which the gel is immersed, and to add other characteristics to the gel. Using this principle, after forming one kind of gel in the reaction container, the liquid in the gel can be replaced by replacing the reaction liquid in the reaction container with a replacement liquid using a pump. .
This makes it possible to produce a plurality of types of gels using a common stereolithography apparatus.
Moreover, it becomes possible to hold | maintain a gel for a long time by inject | pouring a shape retention liquid in a reaction container.

<Fifth Embodiment>
Next, a fifth embodiment of the optical modeling method and the optical modeling apparatus to which the present invention is applied will be described.
FIG. 7 is a diagram showing the shape of the tip of the optical fiber in the fifth embodiment.
In the fifth embodiment, a lens portion 23 having a substantially spherical convex surface is formed at the protruding end portion of the distal end portion 21 a of the optical fiber 21.
According to the fifth embodiment described above, the spot diameter at which two-photon excitation occurs can be reduced by the lens effect of the lens unit 23.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) In each embodiment, the reaction vessel is fixed and the optical fiber that is an optical element is moved to perform modeling. However, the present invention is not limited to this, and the reaction vessel side may be moved. .
(2) In each embodiment, the optical fiber is moved using a triaxial robot. However, the means for moving the optical element is not limited to the triaxial robot, and other means such as a SCARA robot may be used. .

DESCRIPTION OF SYMBOLS 1 Stereolithography apparatus 10 Reaction container 20 Laser oscillator 21 Optical fiber 21a Tip part 21b Core 21c Metal film 22 Holder 23 Lens part 30 Triaxial robot 31 Base part 32 Tower 33 Arm 34 Holder holding part T1 Reaction liquid tank T2 Replacement liquid tank T3 Shape Retentate tank P1-P3 Pump

Claims (13)

The reaction liquid that gels by irradiating with light is stored in the reaction container,
Put an optical element whose tip emits light below the surface of the reaction solution,
A light that induces a reaction by irradiating the reaction solution with the optical element while relatively moving the optical element and the reaction container to form a three-dimensional object made of a gel-like body in the reaction container. Modeling method. The optical modeling method according to claim 1, wherein the optical element is an optical element that generates near-field light from a tip portion. The optical modeling method according to claim 1, wherein the optical element induces a reaction by two-photon excitation by light irradiation from a tip portion. According to the relative height between the optical element and the reaction vessel, the liquid level of the reaction solution in the reaction vessel so that the insertion depth of the optical element into the reaction solution is within a predetermined range. The stereolithography method according to any one of claims 1 to 3, wherein: 5. The stereolithography method according to claim 1, wherein the reaction liquid has a specific gravity substantially similar to that of the gel-like body formed by irradiation with light. . The said reaction container is equipped with the means to extract the said reaction liquid and inject | pour another substitution liquid and shape retention liquid, The optical modeling method of any one of Claim 1 to 5 characterized by the above-mentioned. . A reaction vessel for storing a reaction solution that gels when irradiated with light; and
An optical element whose tip emits light;
An optical modeling apparatus comprising: a relative moving unit configured to relatively move the optical element and the reaction container in a state where a tip portion of the optical element is placed in the reaction solution in the reaction container. The stereolithography apparatus according to claim 7, wherein the relative movement device includes a triaxial robot that can drive the optical element in three orthogonal directions. The optical modeling apparatus according to claim 7, wherein the optical element is an optical element that generates near-field light from a tip portion. The optical modeling apparatus according to claim 7 or 8, wherein the optical element induces a reaction by two-photon excitation by light irradiation from a tip portion. A reserve tank provided outside the reaction vessel;
A pump for extracting the reaction liquid in the reaction container and storing it in the reserve tank, and returning the reaction liquid stored in the reserve tank into the reaction container;
Depending on the relative height between the optical element and the reaction vessel, the reaction in the reaction vessel is performed such that the pump is driven and the insertion depth of the optical element into the reaction solution is within a predetermined range. The optical modeling apparatus according to claim 7, further comprising: a control unit that changes a liquid level height of the liquid. The stereolithography apparatus according to any one of claims 7 to 11, wherein the reaction liquid has a specific gravity substantially similar to that of the gel-like body formed by light irradiation. . The said reaction container is equipped with the means to extract the said reaction liquid and inject | pour another substitution liquid and shape retention liquid. The optical modeling apparatus of any one of Claim 7-12 characterized by the above-mentioned. .

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