JP2003220619A - Optical element and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element which can reduce peeling force when peeling is started and improve the durability of a mold by preventing the peeling from a glass substrate, deformation, and breakage of a resin, and to provide a method for producing the optical element. <P>SOLUTION: In the optical element, a shape photocurable resin is copied by using a mold, cured by being irradiated with light, and demolded to form the resin having necessary shape on a base material. Two areas different in demoldability exist on a resin/mold interface, the inside is an area poor in demoldability, and the outside is an area good in demoldability. In the method for producing the optical element in which the resin is shape-transferred by using the mold, cured by being irradiated with light, and demolded to form the resin having the necessary shape on the base material, the material of a contact surface is different from the resin of a mold. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens having an aspherical surface, an optical element having a fine shape (unevenness) on the surface thereof, such as a diffraction grating, a Fresnel lens, an optical disk substrate, and a method for manufacturing the same.

[0002]

2. Description of the Related Art The method of manufacturing an optical element includes grinding glass,
There are polishing, precision molding using a mold, injection molding of thermoplastic resin, press molding, etc., and they are used properly depending on the function, cost, required accuracy, etc. For example, for aspherical lenses used for imaging lenses used in cameras, etc., aspherical lenses are manufactured by grinding and polishing glass, which has less performance deterioration due to environmental changes in temperature and humidity, and is economically advantageous. Is manufactured by precision molding of glass using a mold. Since lenses used for viewfinders in cameras are not required to have excellent imaging performance, they are manufactured by resin injection molding in terms of cost.

Further, in an aspherical lens having a diameter of 30 mm or more and an optical element having fine irregularities on the surface, a required layer is formed by molding a thin layer of a light energy curable resin on a glass substrate and curing the resin. A method of forming a surface profile is used. The precision of shape of a large aspherical lens deteriorates in precision molding of glass, and if the precision is to be secured, the molding time becomes long and the cost becomes high. Even optical elements with fine irregularities cannot be manufactured with glass because the irregularities are destroyed during mold release,
Manufacturing with resin is essential, but if the entire element is resin,
The performance is greatly deteriorated due to environmental fluctuations, and the influence is reduced by the above-mentioned method of forming the resin portion as a thin layer.

As a mold releasing method in the molding of this light energy curable resin, for example, JP-A-63-131352 is used.
Release by protrusion of No. JP-A No. 01-152015, release using heat stress due to heating and cooling, JP-A-62-2015
-117154 vibration causes mold release. Examples of the mold releasability improvement include a mold having a good mold releasability of Japanese Patent No. 2680175, a mold having a mold releasing agent treatment of Japanese Patent No. 3006199, and a resin of Japanese Patent Application Laid-Open No. 04-254801 containing an internal release agent. Proposals have been made to include it.

[0005]

In the molding of light energy curable resin, if the release is hindered, the resin peels from the base material, the surface shape of the resin changes, or the surface is fine. In an element having unevenness, the unevenness may be destroyed. Further, not only the shape accuracy is adversely affected, but also the releasability greatly affects the cost in terms of production tact (molding time) and mold durability. The above-mentioned proposals have been made to improve the releasability as described above, but the above three cases are related to the load method for the releasability and are not intended to reduce the force required for the releasability. Therefore, at the time of mold release, considerable stress acts on the resin / mold interface, and not all of the above problems are solved.

Also, the latter three cases are reduction of the releasing force itself,
Improvements in mold surface materials and resin compositions have been considered.

However, if the mold surface material has a good releasing property,
Like Teflon (registered trademark), it has a poor surface roughness and cannot be used for optical applications, and the release agent also has a short durability, and adversely affects the appearance and the environmental durability of the resin after molding. In addition, in improving the resin composition, the releasability of the internal release agent is improved, but this also reduces the mold durability due to mold stains, the appearance of the molded product, and the environment of the resin after molding. It adversely affects durability.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the releasing force at the time of starting the releasing, and to separate, deform and destroy the resin from the glass substrate. It is an object of the present invention to provide an optical element and a method for manufacturing the same that can prevent the above-mentioned phenomenon and improve the durability of the mold.

[0009]

In order to achieve the above object, the present invention requires a light energy curable resin on a substrate by transferring a shape using a mold, curing by light irradiation, and releasing. In an optical element formed with a light energy curable resin having the shape of, there are two regions having different releasability at the resin / mold interface, the inner region has poor releasability, and the outer region has good releasability. Is characterized in that.

Further, according to the present invention, a light energy curable resin having a desired shape is formed on a substrate by transferring a shape of a light energy curable resin using a mold, curing by light irradiation, and then releasing the resin. In the method of manufacturing an optical element described above, different materials are used for the contact surface with the resin of the mold.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

According to the present invention, in order to reduce the releasing force itself, particularly to reduce the releasing force at the time of starting the releasing, a region having different releasing properties is present at the resin / mold interface, and the inside has the releasing property. By setting the bad region and the region having good releasability on the outer side, as shown in FIG. 11, the region 21a having good releasability of the resin 21 starts peeling under a low load, and the region 21b having poor releasability is separated. Since the opening angle between the resin and the mold 22 is close to 0 degree at the start of the mold, stress concentrates on the exfoliation tip, and mold release with a low load becomes possible. Where 2
2a is a region where the mold releasability is good, and 22b is a bad region.

[Embodiment 1] FIG. 1 is a schematic view showing an embodiment of an optical element according to the present invention, FIG. 2 is a schematic view showing a mold used in this embodiment, and FIG. 3 is an optical element in this embodiment. FIG.

In FIG. 1, 1 is a light energy curable resin and 2 is a glass substrate. On the surface 1c of No. 1, fine irregularities transferred by the mold are formed. Reference numeral 1a is a resin good release part, and 1b is a bad release part. This molded product is shown in Figure 2.
It was produced using the mold shown in.

FIG. 2 shows a mold having a groove 3c having a depth of 0.5 μm formed on quartz by a photolithography method and an etching method, and a fluorine-based mold release agent having a thickness of 1 μm or less and a thickness of 50 μm is provided on the outer side 3a of the groove forming portion. Is coated. 3b is a part where the surface is still quartz, which is not coated with a fluorine-based release agent. Using this mold, a diffraction grating having fine irregularities on the surface was produced in the process shown in FIG.

In FIG. 3, 4 is a light energy curable resin before curing, 5 is a spacer, and 6 is a release pin connected to a driving device (not shown). First, the light energy curable resin 4 is dropped on the mold 3 (FIG. 3A), the glass base material 2 is placed thereon, and pressure is applied by an apparatus (not shown). A silane coupling agent is applied to the contact surface of the glass base material used with the resin for improving the adhesion. Then, when the resin thickness is determined by the spacer (FIG. 3B), light is irradiated to cure the resin (FIG. 3C).

When the curing was completed, the glass part was released from the mold while gradually increasing the pressure with a release pin (FIG. 3 (d)). Three
The end of part a starts to release at about 20 kN and it is 20 kN as it is.
Then, the mold was released up to the end of 3b, and the end of the 3b part started to be released at 30 kN, and the entire surface was released at 30 kN for about 10 seconds.

The light energy curable resin having a diffraction grating formed on the surface thus molded had no peeling between the resin and the glass substrate, and there was no chipping or deformation of the edge portion of the grating, and the mold was repeatedly used for 1000 shots. No change was observed in molding.

<Comparative Example 1> Molding was carried out in the same manner as in Example 1 except that a mold having no fluorine-based release agent coating was used. It took 150 kN to start the mold release, and the mold was released at once in less than 1 second. did. In the molded product, the resin was partly peeled from the glass substrate.

[Embodiment 2] FIG. 4 is a schematic view showing an embodiment of an optical element according to the present invention, FIG. 5 is a schematic view showing a mold used in this embodiment, and FIG. 6 is an optical element in this embodiment. FIG.

In FIG. 4, 7 is a light energy curable resin and 8 is a glass base material. The surface 7c of 7 has a Fresnel shape transferred by a mold. Reference numeral 7a is a resin good release part, and 7b is a bad release part. This molded product was produced using the mold shown in FIG.

Reference numeral 9 in FIG. 5 is a mold having a Fresnel shape having a maximum depth of 25 μm on the surface, and KN is formed on a phosphor bronze base material 9a.
The plating 9b was applied to a thickness of 50 μm, and the plating layer was cut to form a Fresnel shape 9c. Figure 6
An optical element having a Fresnel-shaped resin layer adhered on the surface of a glass substrate was produced in the step shown in FIG.

In FIG. 6, 10 is a light energy curable resin before curing, 11 is a spacer, 12 is a mask, 13
Is a release pin connected to a drive device (not shown).
First, the light energy curable resin 10 is dropped on the mold 9 (FIG. 6A), the glass base material 8 is placed thereon, and pressure is applied by an apparatus (not shown). A silane coupling agent is applied to the contact surface of the glass base material used with the resin for improving the adhesion. Then, when the resin thickness is determined by the spacer (FIG. 6B), light is irradiated to cure the resin (FIG. 6B).
(C)). Here, after the resin was cured to a gel state, light irradiation was performed through the mask 12. Therefore, the 7a portion of the resin remains in the gel state (FIG. 6 (d)).

When the curing of the resin 7b portion is completed, the glass portion is released from the mold while gradually increasing the pressure by the release pin (FIG. 6).
(E)). The end of the 7a portion started to release at about 10 kN, the release was continued at 10 kN to the end of 3b, the end of the 3b portion started to release at 30 kN, and the entire release was continued at 30 kN for about 10 seconds. After releasing the mold, this time only the uncured portion 7a was irradiated with light to cure the portion 7a.

In the light energy curable resin having the Fresnel shape formed on the surface thus molded, the resin and the glass substrate were not separated from each other, and the edges of the lattice were not chipped or deformed, and the mold was repeatedly used for 1000 shots. No change was observed in molding.

Comparative Example 2 The same molding as in Example 2 was carried out except that the entire surface was cured without masking during curing, but 200 kN was required to start the mold release, and the mold was released at once in less than 1 second. did. The edge of the Fresnel part of the molded product was chipped, and resin adhesion was found on the mold.

[Embodiment 3] FIG. 7 is a schematic view showing an embodiment of an optical element according to the present invention, FIG. 8 is a schematic view showing a mold used in this embodiment, and FIG. 9 is an optical element in this embodiment. FIG. 3 is a schematic view showing a manufacturing method of.

In FIG. 7, 14 is a light energy curable resin, and 15 is a glass base material. The surface shape of 14 is an aspherical surface 14c transferred by a mold. Reference numeral 14a is a resin good release part, and 14b is a bad release part. This molded product was produced using the mold shown in FIG. Reference numeral 16 in FIG. 8 is made of cemented carbide, and the surface 16a is processed into an aspherical surface by grinding and polishing, and the surface roughness Ra is finished to 2 nm or less. The periphery 17 is made of Teflon, and the surface 17a is lapped, but the surface roughness is Ra.
Was about 200 nm. Using this mold, an optical element was produced in which a resin layer having an aspherical surface was adhered onto a glass substrate in the step shown in FIG.

In FIG. 9, 18 is a light energy curable resin before curing, and 19 is a release pin connected to a driving device (not shown). First, the light energy curable resin 18 is dropped on the mold 16 (FIG. 9A), the glass base material 15 is placed thereon, and pressure is applied by an apparatus (not shown). A silane coupling agent is applied to the contact surface of the glass base material used with the resin for improving the adhesion. When the resin thickness is determined by the glass coming into contact with the release pin (see FIG. 9).
(B)), light is applied to cure the resin (FIG. 9).
(C)).

When the curing is completed, the glass portion 15a is released from the mold while gradually increasing the pressure by the release pin (FIG. 9).
(D)). The end of the 14a portion starts to release at about 20 kN,
The mold was released as it was up to the end of 14b at 20 kN, and the end of the 14b part started to be released at 30 kN, and the entire surface was released at 30 kN in about 10 seconds.

In the light energy curable resin having the aspherical surface formed on the surface thus molded, the resin and the glass base material were not separated from each other, and the shape accuracy was such that the shape of the mold was transferred at 0.1 μm or less. .

Also, the mold did not show any change after repeated molding of 1000 shots.

Comparative Example 3 When molding was carried out in the same manner as in Example 3 except that the Teflon portion was made of cemented carbide, 300 kN was required to start demolding, the resin peeled from the glass substrate, and the resin remained on the mold. It adhered.

[Embodiment 4] FIG. 10 is a schematic view showing the mold used in this embodiment. The mold used in Embodiment 1 is coated with a fluorine-based releasing agent having a diameter of 1 μm or less as 20a. The molding was performed in the same manner as in Example 1 except that the glass portion outside the 20a portion was pressed during release.

The light energy curable resin having the diffraction grating formed on the surface thus molded did not peel off the resin and the glass base material as in Example 1, and did not have chipping or deformation of the edge portion of the grating. Also, no change was observed in the mold after repeated molding of 1000 shots.

[0036]

As described above, according to the present invention,
By providing a difference in releasability at the resin / mold interface and making the part to be released first good, the release force at the start of release can be reduced, and peeling, deformation and destruction of the resin from the glass substrate Prevents and improves mold durability.

Further, according to the present invention, the difference in releasability can be easily realized by changing the surface material of the mold, and the difference in releasability can be realized without changing the mold.

[Brief description of drawings]

FIG. 1 is a schematic view showing an optical element in a first example.

FIG. 2 is a schematic view showing a mold used in the first embodiment.

FIG. 3 is a schematic diagram showing a method for manufacturing an optical element in the first embodiment.

FIG. 4 is a schematic diagram showing an optical element according to a second embodiment.

FIG. 5 is a schematic view showing a mold used in the second embodiment.

FIG. 6 is a schematic view showing a method for manufacturing an optical element in the second embodiment.

FIG. 7 is a schematic diagram showing an optical element in a third embodiment.

FIG. 8 is a schematic view showing a mold used in a third embodiment.

FIG. 9 is a schematic view showing a method for manufacturing an optical element in the third example.

FIG. 10 is a schematic view showing a mold used in a fourth embodiment.

FIG. 11 is a diagram showing a condition of a resin / mold interface at the time of mold release according to the present invention.

[Explanation of symbols]

1,7,14,21 Light energy curable resin 2,8,15 after molding and curing Glass substrate 3,9,16,17,20,22 Mold 4,10,18 Light energy curable resin 5 before curing , 11 Spacer 6,13,19 Release pin 12 Mask

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 7/26 531 G11B 7/26 531 // B29K 101: 10 B29K 101: 10 B29L 11:00 B29L 11: 00 F term (reference) 4F202 AA44 AH73 AH74 AJ03 AJ09 AJ11 CA01 CB01 CD22 CK11 CK83 4F204 AA44 AH73 AH74 AH75 EA03 EA04 EB01 EF01 EK17 EK18 EK24 EK25 5D029 KB08 MA34 5D121EE02EE02 DD02 A26DD02A06DD02

Claims (4)

[Claims] 1. An optical element in which a light energy curable resin is formed on a substrate by transferring the shape of the light energy curable resin using a mold, curing by light irradiation, and then releasing. An optical element characterized in that there are two regions having different releasability at the resin / mold interface, the region having poor releasability inside and the region having good releasability outside. 2. An optical element in which a light energy curable resin having a desired shape is formed on a substrate by transferring a shape of a light energy curable resin using a mold, curing by light irradiation, and then releasing. A method of manufacturing an optical element, characterized in that different materials are used for the contact surface with the resin of the mold. 3. The method of manufacturing an optical element according to claim 1, wherein the curing state of the light energy curable resin is different. 4. The method for manufacturing an optical element according to claim 3, wherein the masking is performed and light irradiation is performed.