JP2008213210A - Transfer method and optical element manufactured thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fine uneven part not mixed with air bubbles by transferring a mold transfer surface to a resin material after the resin material is temporarily cured. <P>SOLUTION: A resin 12 is interposed between a glass base material 11 and the mold transfer surface arranged in a counter relation to the glass base material 11 and having a fine uneven part 14 formed thereto and the fine uneven part 14 is transferred to the surface of the resin 12. Accordingly, a transfer method includes a process of dripping the resin 12 of low viscosity on the molding surface of the glass base material 11 to uniformly coat the molding surface of the glass base material 11, a process of temporarily curing the coated resin 12 before the resin 12 comes into contact with the transfer surface, a process of pressing the transfer surface to the temporarily cured resin 12, a process of finally curing the resin 12 in the pressed state and a process of releasing a composite 22 containing the finally cured resin 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transfer method for transferring fine irregularities on the surface of a resin material and an optical element manufactured by the transfer method.

  In a lens of an optical system, after a light beam emitted from one point passes through the lens, a phenomenon (called “aberration”) occurs that the light rays are scattered without being collected at one point. Among these aberrations, chromatic aberration is caused by the property that the refractive index varies depending on the wavelength of light. As a method for correcting the chromatic aberration of this optical system, a technique using a diffractive optical element is conventionally known.

  For example, Patent Document 1 discloses a technique for transferring a fine uneven portion. In this technique, first, a photo-curing resin is applied to the surface of a flat transparent substrate. And the original of a fine uneven part is made to adhere to this photocuring resin gradually. Next, the light curing resin is cured by irradiating the transparent substrate with light from the side opposite to the original. In addition, the original plate is moved gradually during curing.

Patent Document 2 discloses a technique for suppressing the generation of flare light. In this technique, the vertical surface of the diffraction grating is matted. That is, by forming two layers of carbon-based films having different surface roughnesses, only the vertical surface of the diffraction grating portion is made fine. By transferring this shape to the molded product, the vertical surface of the diffractive optical element is matted.
JP 2004-205924 A JP 2006-162863 A

  In Patent Document 1, an ultraviolet curable resin is dropped on a flat glass substrate, and the ultraviolet curable resin is spread by a mold having fine irregularities. At this time, since there are no fine uneven portions on the surface of the glass substrate, the entrainment of bubbles at the time of dropping the ultraviolet curable resin is not a problem.

  However, since the resin spreads on the fine irregularities at the moment when the resin dropped on the glass substrate comes into contact with the mold having the fine irregularities, it is easy to entrain bubbles. And since this bubble has a bad influence on optical performance, the yield of a product falls.

In Patent Document 2, an ultraviolet curable resin is dropped onto a mold having a fine uneven portion (diffraction grating), and the ultraviolet curable resin is spread by a glass substrate and then cured by irradiation with ultraviolet rays.
However, when an ultraviolet curable resin is dropped onto a mold having fine uneven portions, bubbles are easily involved when the ultraviolet curable resin spreads in contact with the fine uneven portions. For this reason, a yield falls like patent document 1. Moreover, in order to remove this bubble mixing, the deaeration process which decompresses the inside of a vacuum vessel and extracts a bubble is put. For this reason, productivity falls.

  Moreover, since both the techniques of Patent Document 1 and Patent Document 2 are cured after a curable resin is interposed between the substrate and the mold, the amount of resin shrinkage (curing shrinkage) during resin curing is small. Large and fine irregularities are damaged.

  The present invention has been made in order to solve such a problem, and by transferring a mold transfer surface on which a fine uneven portion has been formed to a resin material after temporarily curing the resin material, the fine uneven portion having no air bubbles mixed therein. It is an object of the present invention to provide a transfer method capable of obtaining the above and an optical element manufactured by the transfer method.

  It is another object of the present invention to provide a transfer method capable of reliably forming fine irregularities and an optical element manufactured by the transfer method.

In order to achieve the object, the invention according to claim 1
In the transfer method of transferring the fine irregularities on the surface of the resin material using the transfer surface of the mold in which the fine irregularities are formed,
Dropping and applying the resin material on the molding surface of the substrate;
A step of temporarily curing the applied resin material before contacting the mold transfer surface;
Pressing the mold transfer surface against the temporarily cured resin material;
A step of fully curing the resin material in the pressed state;
And releasing the composite containing the resin material and the base material that have been cured.

The invention according to claim 2 is the transfer method according to claim 1,
The temporary curing step is characterized in that the curing rate of the resin material is 20% to 70%.

The invention according to claim 3 is the transfer method according to claim 1 or 2,
In the pressing step, the temporarily cured resin material and a part of the mold transfer surface are brought into contact with each other, and thereafter, the pressing is performed so as to gradually widen the contact surface.

The invention according to claim 4 is the transfer method according to any one of claims 1 to 3,
In the pressing step, when the curvature radius of the base material molding surface is R1, and the curvature radius of the mold transfer surface is R2,
When the mold transfer surface is flat or concave, the substrate molding surface is a convex surface satisfying | R1 | <| R2 |
When the mold transfer surface is a convex surface, the base material molding surface is a concave surface satisfying | R1 |> | R2 |.

The invention according to claim 5 is the transfer method according to any one of claims 1 to 4,
In the main curing, the substrate and the mold transfer surface are pressed while moving in the proximity direction.

The invention according to claim 6 is the optical element manufactured by the transfer method according to any one of claims 1 to 5,
It comprises the substrate and the resin material.

  According to the present invention, a fine concavo-convex portion free from bubbles can be obtained. Moreover, the fine uneven | corrugated | grooved part by which shaping | molding was performed reliably can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Overview)
1A to 1G are diagrams showing an outline of an embodiment of the present invention.

  In this embodiment, as shown to Fig.1 (a), the energy curable resin 1 is dripped and apply | coated on the molding surface 11a of the glass base material 11 from the nozzle 10 (application | coating process). Examples of the energy curable resin 1 include a thermosetting resin 12 and an ultraviolet curable resin 13 (see the embodiments described later). Moreover, the molding surface 11a of the glass base material 11 is a smooth concave curved surface in this embodiment.

  Then, as shown in FIG. 1B, the applied energy curable resin 1 is spread to a substantially uniform thickness (a spreading step). Next, as shown in FIG. 1C, the energy curable resin 1 is irradiated with energy (ultraviolet light) by an ultraviolet lamp 15 to make the energy curable resin 1 semi-cured (temporarily cured) (temporary). Curing step).

  Further, as shown in FIG. 1D, the semi-cured energy curable resin 1 and the transfer surface of the mold 16 are brought into contact with each other, and the semi-cured energy curable resin 1 is further contacted with the transfer surface of the mold 16. Is pressed (pressing step). A fine uneven portion 14 is formed on the transfer surface of the mold 16.

  Then, as shown in FIG. 1 (e), the energy curable resin 1 is irradiated with energy (ultraviolet light) by an ultraviolet lamp 15 to cure the energy curable resin 1 (main curing step). At that time, energy irradiation is performed while bringing the mold 16 close to the glass substrate 11. Finally, as shown in FIG. 1F, the glass substrate 11 and the energy curable resin 1 (composite) are released from the mold 16 (release process).

As described above, in the present embodiment, the energy curable resin 1 is made semi-cured before the energy curable resin 1 and the fine uneven portion 14 are brought into contact with each other. This point will be described.
The energy curable resin 1 is a liquid in an uncured state. For this reason, when the energy curable resin 1 is brought into contact with the fine concavo-convex portion 14, there is a possibility that bubbles are caught in the energy curable resin 1 due to the “wetting properties” of the fine concavo-convex portion 14 and the resin. The “wetting property” refers to a phenomenon in which, for example, when a liquid is dropped on the surface of a solid, the liquid spreads around the gas while pushing the gas.

  When the energy curable resin 1 comes into contact with the fine concavo-convex portion 14 in an uncured (liquid) state, the energy curable resin 1 pushes the air between itself (energy curable resin 1) and the fine concavo-convex portion 14. While spreading quickly around. However, there are recesses 18 in the fine irregularities 14 (see FIG. 1G).

  Therefore, as shown in FIG. 1G, the resin expands before the energy curable resin 1 is filled in the recess 18, and the air 20 is trapped in the recess 18. Then, the trapped air becomes bubbles and remains in the energy curable resin 1.

  Therefore, in the present embodiment, the energy curable resin 1 is semi-cured (the curing rate is 20% to 70%, preferably before the energy curable resin 13 and the fine uneven portion 14 are brought into contact with each other, that is, in the step of temporarily curing. 30% to 50%). Thereafter, the energy curable resin 1 and the fine concavo-convex portion 14 are brought into contact with each other. The curing rate will be described later.

  If it does in this way, the speed which the energy curable resin 1 spreads will become slow compared with an uncured state. Therefore, the energy curable resin 1 spreads around the air 20 between the self (energy curable resin 1) and the fine concavo-convex portion 14 while reliably pushing away. That is, the air 20 in the recess 18 can also be reliably pushed away. As a result, the fine concavo-convex portion 14 free from bubbles can be obtained.

Here, although the fine uneven part 14 may be pressed against the energy curable resin 1, the energy curable resin 1 may be pressed against the fine uneven part 14.
In the pressing step, it is preferable that the temporarily cured energy curable resin 1 and the fine concavo-convex portion 14 are pressed so that a part of both contacts first and then the contact surface is gradually expanded. .

  For example, it is assumed that the shape of the surface of the resin layer of the energy curable resin 1 is the same as the basic shape (the shape when the fine unevenness is removed) of the fine unevenness 14. In this case, at least one of the fine concavo-convex portion 14 side and the energy curable resin 1 side may be inclined so that one end of the resin layer and one end of the fine concavo-convex portion 14 contact each other first.

  Further, for example, when the surface shape of the energy curable resin 1 is a curved surface, the basic shape of the fine uneven portion 14 may be set so that the center of the resin layer and the center of the fine uneven portion 14 are in contact first.

  Specifically, as shown in FIG. 11 described later, when the curvature radius of the molding surface 11a of the glass substrate 11 is R1, and the curvature radius of the mold transfer surface is R2, the mold transfer surface is flat or concave. In this case, if the molding surface 11a of the glass substrate 11 is a convex surface satisfying | R1 | <| R2 |, and the mold transfer surface is a convex surface as shown in FIG. The surface 11a is a concave surface that satisfies | R1 |> | R2 |. The mold transfer surface is a basic shape of the fine uneven portion 14.

  Here, when the energy curable resin 1 has the above-described curing rate, when the energy curable resin 1 is pressed by the fine concavo-convex portion 14 formed on the transfer surface of the mold 16, the energy curable resin 1 becomes the fine concavo-convex portion. Deforms gradually in accordance with 14. As a result, the shape as it is is transferred.

  In this way, by pressing after the energy curable resin 1 is temporarily cured, a part of the fine concavo-convex portion 14 is in point contact or line contact with the energy curable resin 1. Then, the contact surface (contact range) gradually expands. Therefore, there is no room for the air 20 intervening in the concave portion 18 of the fine concave and convex portion 14 to enter the resin layer, so that entrainment of bubbles is prevented.

  That is, when the resin is filled into the many concave portions 18 of the fine uneven portions 14 formed on the transfer surface of the mold 16, the air 20 in the concave portions 18 is pushed away without being caught in the semi-cured resin. It seems to run away. As a result, a fine uneven portion 14 ′ (see FIG. 4 and the like) free from bubbles is obtained in the resin layer to which the fine uneven portion 14 has been transferred.

Moreover, since the energy curable resin 1 has the above-described curing rate, the uniformity of the thickness of the energy curable resin 1 can be prevented from being lost.
The curing rate is a value representing, for example, how much curing of the (energy curable) resin has progressed. Here, a state where the curing does not proceed further (completely cured state) is 100%, and a state where the curing is not progressing (uncured state) is 0%. For example, when the curing rate is measured from the amount of heat generated when the resin is cured by thermal analysis using a differential scanning calorimetry method, the curing rate is defined by the following equation.

Curing rate = (1− (amount of heat generated until the semi-cured resin is completely cured) / (total amount of heat generated until the uncured resin is completely cured)) × 100
Thus, the curing rate can be obtained by measuring the amount of heat of the energy curable resin 1.

In addition to the differential scanning calorimetry method, for example, an infrared absorption spectrum method, a solvent extraction method, and a measurement method using mechanical property values are known for the measurement of the curing rate.
(First embodiment)
2 (a) to 2 (e) illustrate a case where a thermosetting resin 12 as an energy curable resin is applied on a glass substrate 11 (outer diameter Φ15 mm, thickness 2 mm) 11 that has been polished flat, and fine uneven portions are applied to the resin. 14 is a diagram showing an embodiment in which 14 is transferred.

  That is, as shown in FIG. 2A, a coupling process for increasing the adhesion between the thermosetting resin 12 and the glass substrate 11 is performed on the molding surface 11 a of the flat glass substrate 11. Thereafter, as shown in FIG. 2B, the glass substrate 11 is rotated at 1500 rpm by a spinner, and the urethane-based thermosetting resin 12 is uniformly applied to the molding surface 11a. In this way, the applied thermosetting resin 12 is uniformly stretched to form a resin layer having a resin thickness of about 0.1 mm. The resin used in this embodiment has a viscosity at 25 ° C. of about 500 cps.

  Next, this resin layer is heated at 80 ° C. for 4 minutes to temporarily cure the resin layer. At this time, the curing rate of the resin was about 30% in this embodiment. At this curing rate, the gel state (elastic body) is such that it deforms when a weak pressure is applied.

  Next, as shown in FIG. 2 (c), the mold 16 having the fine irregularities 14 formed on the transfer surface is arranged to face the resin layer substantially in parallel. Further, as shown in FIG. 2D, the transfer surface of the mold 16 is pressed against the resin layer until the thickness of the resin layer becomes about 0.08 mm.

Thereafter, in the state shown in FIG. 2 (d), heating is performed at 80 ° C. for 30 minutes to completely cure the resin layer.
Further, as shown in FIG. 2 (e), by separating the transfer surface of the mold 16 from the resin layer, a fine uneven portion 14 'in which the fine uneven portion 14 is inverted is formed on the transfer surface side of the resin layer. Is done. In this way, a composite body (microstructure) 22 composed of the glass substrate 11 and the thermosetting resin 12 having the fine uneven portions 14 ′ is obtained.

  In the present embodiment, the fine irregularities 14 formed on the transfer surface of the mold 16 have an antireflection structure. In the manufacturing method, a resist pattern is formed on a quartz substrate by an electron beam and then etched to form a periodic structure of a fine quadrangular pyramid on the quartz substrate.

  FIG. 3 is an external view of the fine uneven portion 14 on the transfer surface of the mold 16. The fine concavo-convex portion 14 has a large number of concave portions 18 and convex portions 19, and the pitch p is 150 nm and the height h is 250 nm.

  FIG. 4 is an external view of the fine concavo-convex portion 14 ′ formed by transfer on the thermosetting resin 12. This fine concavo-convex portion 14 ′ has a feature that it has a large number of concave portions 18 ′ and convex portions 19 ′, and there is no bubble entrainment inside the convex portions 19 ′.

  According to the present embodiment, it is possible to obtain a fine concavo-convex portion 14 ′ in which no bubbles are involved. Thus, a composite optical element having good optical performance can be obtained by applying the transfer method of the fine uneven portion 14 to, for example, an optical system.

In the present embodiment, the thermosetting resin 12 is temporarily cured before the thermosetting resin 12 is brought into contact with the transfer surface of the mold 16. For this reason, the curing shrinkage of the thermosetting resin 12 has already progressed, and the amount of curing shrinkage during the main curing is small. Thereby, it can prevent that fine uneven | corrugated | grooved part 14 'is damaged carelessly.
(Second Embodiment)
5 (a) to 5 (d) show an embodiment in which a thermosetting resin 12 is applied on a glass substrate 11 (outer diameter Φ15 mm, thickness 2 mm) 11 that has been flat-polished, and fine irregularities 14 are transferred to this resin. It is a figure which shows a form. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

Further, the method of contacting the thermosetting resin 12 and the mold 16 is different from that of the first embodiment.
As shown in FIG. 5A, a coupling process for increasing the adhesion between the thermosetting resin 12 and the glass substrate 11 is performed on the molding surface 11 a of the flat glass substrate 11. Thereafter, the glass substrate 11 is rotated at 1500 rpm by a spinner to uniformly apply the urethane-based thermosetting resin 12. Thus, a resin layer having a resin thickness of about 0.1 mm is formed. The resin used in this embodiment has a viscosity at 25 ° C. of about 500 cps.

  Then, the resin layer is heated at 80 ° C. for 4 minutes to temporarily cure the resin layer. At this time, the curing rate of the resin was about 30%. In this state, the gel state is such that it deforms when a weak pressure is applied to the resin.

Note that the fine irregularities 14 on the mold transfer surface used in this embodiment are the same as those in the first embodiment.
Then, as shown in FIG. 5 (a), the mold 16 having the fine irregularities 14 formed on the transfer surface is opposed to the resin surface in an inclined state of about 2 °. Next, as shown in FIG. 5B, the transfer surface of the mold 16 is brought into contact with one end (the right end in the figure) of the resin layer. Further, the mold transfer surface presses the resin layer in parallel so that the other end is rotated around one end of the transfer surface of the mold 16. That is, the inclination of the mold 16 is gradually returned to parallel.

  Then, as shown in FIG. 5C, the inclined mold transfer surface acts to gradually expand the contact surface of the resin layer from the point contact or line contact state to the resin layer. In this way, the mold transfer surface is pressed against the resin layer until the thickness of the resin layer is uniformly about 0.08 mm.

Thereafter, heating is performed at 80 ° C. for 30 minutes to completely cure the resin layer.
Furthermore, as shown in FIG. 5 (d), by separating the transfer surface of the mold 16 from the resin layer substantially in parallel, a fine uneven portion 14 ′ free from entrainment of bubbles can be obtained. In this way, the composite body 22 in which the glass substrate 11 and the fine concavo-convex portions 14 ′ are formed is obtained.

According to this embodiment, after a part of the transfer surface of the mold 16 comes into contact with the resin, the mold transfer surface is pressed so as to gradually expand the contact surface. It is possible to prevent entrainment of bubbles.
(Modification)
In the first and second embodiments, the case where the fine uneven portion 14 formed on the transfer surface of the mold 16 has the convex portion 19 of the quadrangular pyramid has been described as an example. Or a polygonal pyramid such as a hexagonal pyramid. Furthermore, the fine concavo-convex portion does not need to have a regular concavo-convex pattern shape, and may have an irregular concavo-convex structure having a pitch and height of several microns or less.

  Moreover, the fine uneven | corrugated | grooved part 14 may be a linear rectangular uneven | corrugated | grooved part whose pitch p and height h are several microns or less, for example, as shown to Fig.6 (a). Further, as shown in FIG. 6B, the fine uneven portion 14 may be a linear saw-tooth uneven portion having a pitch p and a height h of several microns or less.

In this case, when the transfer surface of the mold 16 is pressed against the resin layer, the linear direction of the fine concavo-convex portion 14 and the direction in which the resin contact surface spreads can be made the same to further prevent bubbles from being mixed.
(Third embodiment)
FIGS. 7A to 7E show an implementation in which a thermosetting resin 12 is applied on a glass substrate 11 (outer diameter Φ15 mm, thickness 2 mm) 11 that has been subjected to planar polishing, and fine uneven portions 14 are transferred to this resin. It is a figure which shows a form. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  The difference from the first embodiment is that the glass substrate 11 has a wedge shape with a maximum thickness of 2 mm and a minimum thickness of 1.9 mm. That is, the molding surface 11 a of the glass substrate 11 is inclined with respect to the bottom surface of the substantially horizontal glass substrate 11.

  As shown in FIG. 7A, a coupling process for increasing the adhesion between the thermosetting resin 12 and the glass substrate 11 is performed on the molding surface 11 a of the wedge-shaped glass substrate 11. Thereafter, as shown in FIG. 7B, the glass substrate 11 is rotated at 1000 rpm by a spinner, and the epoxy thermosetting resin 12 is uniformly applied to the resin layer forming surface 11a. Thus, a resin layer having a resin thickness of about 0.2 mm is formed. The resin used in this embodiment has a viscosity at 25 ° C. of about 1000 cps.

  Next, this resin layer is heated at 80 ° C. for 4 minutes to temporarily cure the resin layer. At this time, the curing rate of the resin was about 30%. In this state, the gel state is such that it deforms when a weak pressure is applied to the resin.

  Next, as shown in FIG. 7 (c), the transfer surface of the mold 16 on which the fine irregularities 14 are formed is disposed opposite to and parallel to the bottom surface of the substantially horizontal glass substrate 11. At this time, the mold transfer surface is in a point contact or line contact state at one end (right end in the figure) of the resin layer.

  Further, as shown in FIG. 7D, the mold transfer surface is pressed in parallel with the resin layer until the thickness of the resin layer is about 0.08 mm at the thinnest portion. Thus, the transfer surface of the mold 16 inclined with respect to the resin layer is pressed so as to gradually expand the contact surface. This prevents entrainment of bubbles when forming the fine uneven portion 14 ′ in the resin layer.

The fine irregularities 14 of the mold 16 used in the present embodiment are the same as those in the first embodiment.
Thereafter, in the state shown in FIG. 7D, the resin layer is heated at 80 ° C. for 30 minutes to completely cure the resin layer.

  Further, as shown in FIG. 7E, by separating the transfer surface of the mold 16 from the resin layer, a fine uneven portion 14 ′ in which the fine uneven portion 14 is inverted is formed on the transfer surface side of the resin layer. The In this way, a composite 22 having the glass substrate 11 and the thermosetting resin 12 having the fine irregularities 14 ′ is obtained.

According to the present embodiment, it is possible to prevent air bubbles from being mixed when the fine uneven portion 14 ′ is formed. Further, since the transfer surface of the mold 16 and the resin layer forming surface 11a of the glass substrate 11 are inclined from the beginning, the operation of the mold 16 is linear when the transfer surface is brought close to the resin layer. . For this reason, an apparatus structure can be simplified.
(Fourth embodiment)
8A to 8E show an implementation in which a thermosetting resin 12 is applied on a smoothly polished glass substrate (outer diameter Φ15 mm, thickness 2 mm) 11 and fine uneven portions 14 are transferred to the resin. It is a figure which shows the form of.

  The difference from the third embodiment is that the molding surface 11a of the glass substrate 11 has a convex shape with a radius of curvature R1 = 800 mm, the thickness of the central portion is 2 mm, and the transfer of the mold 16 is performed. The point is that the plane is a plane. That is, the curvature radius R1 of the molding surface of the glass substrate 11 is a convex surface that is smaller than the curvature radius R2 (∞) of the transfer surface of the mold 16.

In addition, the surface (bottom surface) side opposite to the molding surface 11a of the glass substrate 11 is a horizontal plane. Further, the same or corresponding members as those in the first embodiment will be described with the same reference numerals.
As shown in FIG. 8A, a coupling process for increasing the adhesion between the thermosetting resin 12 and the glass substrate 11 is performed on the molding surface 11 a of the glass substrate 11. Thereafter, as shown in FIG. 8B, the glass substrate 11 is rotated at 1000 rpm by a spinner, and the epoxy thermosetting resin 12 is uniformly applied to the molding surface 11a. Thus, a resin layer having a resin thickness of about 0.2 mm is formed, and the radius of curvature of the resin layer transfer surface is substantially equal to R1. Next, the resin layer is heated at 80 ° C. for 8 minutes to temporarily cure the resin layer.

At this time, the curing rate of the resin is about 50%, and in this state, the hardness is such that it deforms when pressure is applied.
Next, as shown in FIG. 8C, the transfer surface of the mold 16 on which the fine irregularities 14 are formed is disposed so as to face the bottom surface of the glass substrate 11 substantially in parallel. Further, as shown in FIG. 8D, the transfer surface of the mold 16 is moved in parallel and pressed against the resin layer until the center thickness of the resin layer becomes about 0.1 mm.

  At this time, the transfer surface of the mold 16 in a horizontal state is pressed against the resin layer having a high central portion so that the contact surface is gradually expanded. This prevents entrainment of bubbles when forming the fine uneven portion 14 ′ in the resin layer.

The fine irregularities 14 of the mold 16 used in the present embodiment are the same as those in the first embodiment.
Thereafter, in the state shown in FIG. 8D, heating is performed at 80 ° C. for 25 minutes to completely cure the resin layer.

  Further, as shown in FIG. 8E, by separating the transfer surface of the mold 16 from the resin layer, a fine uneven portion 14 ′ in which the fine uneven portion 14 is inverted is formed on the transfer surface side of the resin layer. The In this way, a composite 22 having the glass substrate 11 and the thermosetting resin 12 having the fine irregularities 14 ′ is obtained.

According to this embodiment, since the curvature radius R1 of the molding surface 11a of the glass substrate 11 is smaller than the curvature radius R2 of the transfer surface of the mold 16, the curvature radius of the resin layer transfer surface is also reduced. The convex surface is smaller than the radius of curvature R2 of the mold transfer surface, and the transfer surface of the mold 16 is pressed while gradually expanding the contact surface of the resin layer. For this reason, when forming fine uneven part 14 'in a resin layer, it can prevent that a bubble is caught in this fine uneven part 14'.
(Fifth embodiment)
9 (a) to 9 (c), an ultraviolet curable resin 13 as an energy curable resin is applied on a polished glass substrate (outer diameter Φ20 mm, center thickness 2 mm) 11, and fine uneven portions 14 are formed on the resin. It is a figure which shows embodiment which transfers.

  This glass substrate (outer diameter Φ20 mm, center thickness 2 mm) 11 has one optical functional surface having a flat surface and the other optical functional surface having a concave surface with a radius of curvature R1 = 42 mm. This glass substrate 11 has the property that the transmittance of ultraviolet rays (wavelength 365 nm) is 50% or more. In addition, the molding surface curvature radius R1 of the glass substrate is larger than the curvature radius R2 of the transfer surface of the mold 16.

In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.
As shown to Fig.9 (a), the coupling process for raising the adhesiveness of the ultraviolet curable resin 13 and the glass base material 11 is performed to the molding surface (concave surface) 11a of a glass base material. Thereafter, the glass substrate is rotated at 2000 rpm by a spinner, and the acrylic ultraviolet curable resin 13 is uniformly applied to the molding surface 11a.

  Thereafter, the rotation speed is reduced to 1000 rpm, and 20 mW ultraviolet rays are irradiated for 10 seconds in the rotated state. Thus, a temporarily cured resin layer having a resin thickness of about 0.15 mm is formed, and the radius of curvature of the resin layer transfer surface is substantially equal to R1. The resin used in this embodiment has a viscosity at 25 ° C. of about 800 cps.

  At this time, the curing rate of the resin is about 50%, and the hardness is such that it deforms when pressure is applied. Further, the convex transfer surface of the mold 16 on which the fine irregularities 14 are formed is disposed opposite to the molding surface (concave surface) 11 a of the glass substrate 11.

Next, as shown in FIG. 9B, the mold 16 having the fine irregularities 14 formed on the transfer surface is pressed against the resin layer until the center thickness of the resin layer becomes about 0.1 mm.
At this time, the transfer surface of the mold 16 is convex, and the curvature radius R1 of the molding surface (concave surface) 11a of the glass substrate 11 is larger than the curvature radius R2 of the mold transfer surface. The radius of curvature also becomes a concave surface larger than the radius of curvature R2 of the mold transfer surface, and acts so that the contact surface gradually expands after the central portion of the mold transfer surface contacts the central portion of the resin layer. This prevents entrainment of bubbles when forming the fine uneven portion 14 ′ in the resin layer.

Thereafter, the resin layer is completely cured by irradiating with 150 mW ultraviolet light for 2 minutes from the bottom surface side of the glass substrate 11 in the state of FIG. 9B.
At that time, simultaneously with the start of irradiation with ultraviolet rays, the mold 16 was moved at a speed of 5 μm / second for 4 seconds in the direction approaching the glass substrate 11. Thus, by moving the mold 16 close to each other during the main curing, there is no influence of slight curing shrinkage generated in the resin layer during the main curing. For this reason, the shape transferability of the fine irregularities 14 is further improved.

  Further, as shown in FIG. 9 (c), the mold 22 is peeled off from the resin layer, whereby the composite 22 composed of the glass substrate 11 and the ultraviolet curable resin 13 to which the fine irregularities 14 ′ are transferred. Is obtained.

  By the way, as shown in FIGS. 10A to 10C, the fine uneven portion 14 of the mold 16 used in the embodiment of FIG. 9 has a sawtooth shape on a spherical convex surface having a curvature radius R2 = 40 mm. A diffraction grating structure is formed by machining. The sawtooth-shaped pitch p is 1.5 μm to 5 μm, and the height h is 0.8 μm to 3 μm.

  According to this embodiment, the curing time can be shortened by using ultraviolet rays to cure the resin. Further, by moving the transfer surface of the mold 16 close to the resin layer during the main curing of the resin and pressing it against the resin layer, there is no influence of slight curing shrinkage generated during the main curing. For this reason, the shape transferability of the fine irregularities 14 can be further improved.

Furthermore, in the present embodiment, the transfer surface of the mold 16 is a convex surface, and since the curvature radius R1 of the substrate molding surface is larger than the curvature radius R2, the curvature radius of the resin layer transfer surface is also the mold. Since the concave surface is larger than the radius of curvature R2 of the transfer surface and the transfer surface of the mold 16 is pressed while gradually expanding the contact surface of the resin layer, it is possible to prevent entrainment of bubbles when forming the fine uneven portion 14 'on the resin layer. can do.
(Sixth embodiment)
11 (a) to 11 (e) show a polished glass substrate (glass material: BSL-) having a convex surface with a curvature radius of the base material molding surface 11a of R1 = 72 mm and a convex surface with a curvature radius of the non-molding surface of R3 = 82 mm. 7 is a view showing an embodiment in which an ultraviolet curable resin 13 is applied onto an outer diameter Φ 20 mm and a center layer 5 mm) 11 and a fine concavo-convex structure 14 is transferred to the resin.

In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.
As shown in FIG. 11A, a coupling process for increasing the adhesion between the ultraviolet curable resin 13 and the glass substrate 11 is performed on the molding surface 11 a of the biconvex lens-shaped glass substrate 11. Thereafter, as shown in FIG. 11B, the glass substrate 11 is rotated at 1500 rpm by a spinner to uniformly apply the urethane acrylate-based ultraviolet curable resin 13. In this way, a resin layer having a resin thickness of about 0.2 mm is formed, and the curvature half of the resin layer transfer surface is substantially equal to the curvature radius R1 of the substrate molding surface. The resin used in this embodiment has a viscosity at 25 ° C. of about 1500 cps.

  Furthermore, after stopping the rotation of the glass substrate 11, the resin layer is temporarily cured by irradiating with 30 mW ultraviolet rays for 15 seconds. At this time, the curing rate of the resin is about 60%, and the hardness is such that it deforms when a strong pressure is applied.

  Next, as shown in FIG. 11C, the mold 16 having the fine irregularities 14 formed on the transfer surface is brought into substantially uniform contact with the resin layer. Further, as shown in FIG. 11D, the transfer surface of the mold 16 is pressed against the resin layer until the thickness of the central portion of the resin layer becomes about 0.1 mm.

  At this time, the transfer surface of the mold 16 is concave, and the curvature radius R1 of the base material molding surface (convex surface) is smaller than the curvature radius R2 of the mold transfer surface. The convex surface is smaller than the radius of curvature R2 of the mold transfer surface, and acts so that the contact surface gradually expands after the central portion of the mold transfer surface contacts the central portion of the resin layer. This prevents entrainment of bubbles when forming the fine uneven portion 14 ′ in the resin layer.

In the present embodiment, the area of the resin layer is larger than the transfer surface of the mold 16. For this reason, the part which the fine uneven | corrugated | grooved part 14 is not transcribe | transferred has arisen in the outer peripheral part of the resin layer.
After that, the resin layer is completely cured by irradiating with 150 mW ultraviolet rays for 2 minutes from the base material side as it is in FIG.

  Further, as shown in FIG. 11 (e), by separating the transfer surface of the mold 16 from the resin layer, a fine uneven portion 14 ′ in which the fine uneven portion 14 is inverted is formed on the transfer surface side of the resin layer. A composite 22 is obtained.

  As shown in FIGS. 12A to 12C, the fine uneven portion 14 of the mold 16 used in the present embodiment has a spherical concave surface with a radius of curvature R2 = 80 mm as a fine uneven portion 14. It has a sawtooth-shaped diffraction grating structure in a concentric shape with convex sides. Specifically, the fine uneven portion 14 is machined into a shape having a lattice height h = 2 to 10 μm and a lattice width w = 2 to 30 μm.

  In the present embodiment, the transfer surface of the mold 16 is a concave surface, and the convex surface has a curvature radius R1 of the substrate molding surface smaller than the curvature radius R2 of the transfer surface. And after making a resin layer into a semi-hardened state, in order to press the transfer surface of the metal mold | die 16 against this resin layer, this fine uneven | corrugated | grooved part 14 is gradually formed so that it may spread toward an outer peripheral part from a center part. For this reason, it is possible to prevent entrainment of bubbles when forming the fine uneven portion 14 ′ in the resin layer.

  In addition, the structure of the fine uneven | corrugated | grooved part 14 demonstrated above is not limited to the reflection preventing structure and diffraction grating structure as described in each embodiment. In addition to the thermosetting resin 12 and the ultraviolet curable resin 13, the energy curable resin may be a visible light curable resin, an electron beam curable resin, or the like.

(A) is a figure which shows an application process, (b) is a figure which shows a spreading process, (c) is a figure which shows a temporary hardening process, (d) is a figure which shows a press process, (e) is The figure which shows a main hardening process, (f) is a figure which shows a mold release process, (g) is a figure which shows the state by which air is confine | sealed in a recessed part. (A) is a sectional front view of the glass substrate of the first embodiment, (b) is a diagram showing a state in which a thermosetting resin is applied to the molding surface of the glass substrate, and (c) is a resin layer. The figure which shows the state which faced and arrange | positioned the metal mold | die, (d) is a figure which shows the state which pressed the mold transfer surface to the resin layer, (e) is the state which peeled the transfer surface of the metal mold | die from the resin layer. FIG. It is a figure which shows the state which expanded the metal mold | die transfer surface. It is a figure which shows expansion of the fine uneven | corrugated | grooved part transcribe | transferred to the thermosetting resin. (A) is a figure which shows the state which apply | coated thermosetting resin to the molding surface of the glass base material of 2nd Embodiment, and has arrange | positioned the metal mold | die with respect to this resin layer, (b) is this resin layer The figure which shows the state which inclined and pressed the metal mold | transfer surface with respect to (c) is a figure which shows the state which pressed the resin layer and the metal mold | die transfer surface so that it might become parallel, (d), It is a figure which shows the state which peeled the transfer surface of the metal mold | die from the resin layer. (A) is a figure which shows the external appearance of a rectangular fine uneven part, (b) is a figure which shows the external appearance of a sawtooth-shaped fine uneven part. (A) is a front view of the glass base material of 3rd Embodiment, (b) is a figure which shows the state which apply | coated the thermosetting resin to the molding surface of a glass base material, (c) is a resin layer The figure which shows the state which has arrange | positioned the metal mold | die facing, (d) is a figure which shows the state which pressed the mold transfer surface against the resin layer, (e) is the state which peeled the transfer surface of the metal mold | die from the resin layer. FIG. (A) is a front view of the glass substrate of the fourth embodiment, (b) is a diagram showing a state where a thermosetting resin is applied to the molding surface of the glass substrate, and (c) is a resin layer. The figure which shows the state which has arrange | positioned the metal mold | die facing, (d) is a figure which shows the state which pressed the mold transfer surface against the resin layer, (e) is the state which peeled the transfer surface of the metal mold | die from the resin layer. FIG. (A) is the figure which shows the state which apply | coated the ultraviolet curable resin to the concave surface of the glass base material of 5th Embodiment, and has arrange | positioned the metal mold | die with respect to this resin layer, (b) is gold | metal | money to a resin layer. The figure which shows the state which pressed the mold transfer surface, (c) is a figure which shows the state which peeled the transfer surface of the metal mold | die from the resin layer. (A) is a sectional front view of the same mold transfer surface, (b) is an enlarged plan view thereof, and (c) is an enlarged perspective view thereof. (A) is a sectional front view of the glass substrate of the sixth embodiment, (b) is a diagram showing a state in which an ultraviolet curable resin is applied to the molding surface of the glass substrate, and (c) is a resin layer The figure which shows the state which faced and arrange | positioned the metal mold | die with respect to FIG., (D) is a figure which shows the state which pressed the metal mold | die transfer surface against the resin layer, (e) is a resin layer It is a figure which shows the state which peeled from. (A) is a sectional front view of the same mold transfer surface, (b) is an enlarged plan view thereof, and (c) is an enlarged perspective view thereof.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Energy curable resin 11 Glass base material 11a Molding surface 12 Thermosetting resin 13 Ultraviolet curable resin 14 Fine uneven part 15 Ultraviolet lamp 16 Mold 18 Concave part 19 Convex part 20 Air 22 Composite

Claims (6)

In the transfer method of transferring the fine irregularities on the surface of the resin material using the transfer surface of the mold in which the fine irregularities are formed,
Dropping and applying the resin material on the molding surface of the substrate;
A step of temporarily curing the applied resin material before contacting the mold transfer surface;
Pressing the mold transfer surface against the temporarily cured resin material;
A step of fully curing the resin material in the pressed state;
A step of releasing the composite containing the resin material and the base material that has been fully cured. The transfer method according to claim 1, wherein the temporary curing step sets the curing rate of the resin material to 20% to 70%. 3. The pressing step includes contacting the part of the mold transfer surface with the temporarily cured resin material first, and then pressing to gradually widen the contact surface. The transfer method described in 1. In the pressing step, when the curvature radius of the base material molding surface is R1, and the curvature radius of the mold transfer surface is R2,
When the mold transfer surface is flat or concave, the substrate molding surface is a convex surface satisfying | R1 | <| R2 |
4. The transfer method according to claim 1, wherein when the mold transfer surface is a convex surface, the base material molding surface is a concave surface satisfying | R 1 |> | R 2 |. 5. The transfer method according to claim 1, wherein, during the main curing, the substrate and the mold transfer surface are pressed while moving in a proximity direction.   An optical element comprising the substrate and the resin material and manufactured by the transfer method according to claim 1.