JP2003222709A - Optical element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element improving durability of a mold by reducing demolding force in starting demolding, controlling a start point and a direction of the demolding, and preventing peeling, deformation and breakage of a resin from a glass base material, and to provide its manufacturing method. <P>SOLUTION: The optical element forms the energy curable resin having a required shape on a base material by dropping the energy curable resin into the mold, installing the base material thereon, and applying energy on the resin to be cured and demolded. It has a projection-like part in viewing from the orthogonal direction to a base material face on an outer peripheral part of a molding. In addition, the projection-like part is made a demolding start point in the manufacturing method of the optical element forming the energy curable resin having a required shape on the base material by dropping the energy curable resin into the mold, installing the base material thereon, and applying energy on the resin to be cured and demolded. <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, for example, 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,
Manufacture with a resin is indispensable, but if the entire element is a resin, performance deterioration due to environmental fluctuations is large, and the influence is reduced by the above-described method of forming a thin resin 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] Further, in JP-A 06-270166, a mold release in which a resin is attached to the outermost peripheral portion and hardened, is disclosed in JP-A 07-227.
No. 916 proposes a mold release method in which an eccentric load member is brought into contact with a part of the outer base lens portion, and the eccentric load member is used as a starting point.

[0006]

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.

Further, the following 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.

In the last two cases, improvement of the mold releasability is considered starting from a cured resin or an eccentric load member between the mold and the base material.

However, the cured resin for the starting point is added after the main resin is sandwiched between the mold and the base material and cured, and is 180 degrees opposite to the adhesion point of the resin due to the curing shrinkage of the starting resin. It is expected that the mold is released from the side and the mold release direction cannot be controlled, or that the mold release becomes difficult depending on the amount of the resin. Since the one using the eccentric load member is basically the same as the one-claw peeling method in which the pin for releasing is applied to the end of the base material and pushed up, the releasing property is not always improved.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the release force at the start of release and to control the start point of release and the direction of release. An object of the present invention is to provide an optical element capable of improving the durability of a mold by preventing the resin from being peeled off, deformed or destroyed from the base material, and a method for manufacturing the same.

[0012]

In order to achieve the above object, the present invention provides an energy-curable resin dropped into a mold, a base material is placed on the resin, and energy is applied to the resin to cure the resin. In an optical element in which an energy curable resin having a required shape is formed on a substrate by molding,
It is characterized in that the outer peripheral portion of the molded product has a portion having a convex shape when viewed from the direction perpendicular to the surface of the base material.

The present invention also provides an energy curable resin,
A method of manufacturing an optical element in which an energy-curable resin having a desired shape is formed on a substrate by dropping it on a mold, setting a substrate on the mold, applying energy to the resin to cure the resin, and releasing the mold. , The convex portion is used as the release starting point.

[0014]

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

In the present invention, in order to reduce the releasing force itself, particularly the releasing force at the time of starting the releasing, a convex portion 1101 is formed on the outer peripheral portion of the resin 1101 molded as shown in FIG.
a and 1101c, 1101d, 1101e are provided, and the tips 1101b and 1101c, 1101d, 110
Stress is concentrated on each tip of 1e, and the mold is released with low stress starting from this portion. Where 11
02 is a glass base material.

However, the outer peripheral portion is shown by 1101a, 1 in FIG.
In order to form a convex shape such as 101c, 1101d, and 1101e, the mold structure becomes complicated.

Therefore, in the present invention, as shown in FIG. 12, the spacer 12 is provided between the glass substrate 1204 and the mold 1201.
By using 03, the energy curable resin 12
No. 02 and the resin 1
The film thickness of 202 is controlled.

Further, as shown in FIG. 13, spacers 1301a, 1301b, 1301c, and 1301 divided into four parts.
Using d, the resin is cured to form a convex portion on the outer peripheral portion, and then the spacers 1301a, 1301
1b, 1301c, 1301d are pulled out beforehand. At the time of starting the mold release, the spacers 1301e, 1301f,
Stress is concentrated on the respective tips of the convex portions corresponding to 1301g and 1301h, which enables mold release with a low load.

The embodiments of the present invention will be specifically described below, but the present invention is not limited to these examples.

Example 1 FIG. 1 is a schematic diagram showing an embodiment of an optical element according to the present invention, FIG. 2 is a schematic diagram showing a mold used in this example, and FIG. 13 is a spacer used in this example. And FIG. 3 is a schematic view showing a method of manufacturing an optical element in this embodiment.

In FIG. 1, 101 is a light energy curable resin and 102 is a glass base material. Surface 1 of 101
Fresnel shapes transferred by a mold are formed on 01a and 101b (101a is a ridge portion (mountain portion in cross section), 101b is a valley portion (valley portion in cross section)). The outer circumference of the molded optical element is 101c, 101d, 101e, 10
It is convex like 1f. This molded product was produced using the mold shown in FIG.

Reference numeral 201 in FIG. 2 is a mold having Fresnel shapes 201c and 201d (201c is a valley portion (trough portion in cross section), 201d is a ridge portion (ridge portion in cross section)) having a maximum depth of 30 μm on the surface. KN plating 201b was applied to a thickness of 100 μm on a phosphor bronze base material 201a, and Fresnel shapes 201c and 201d were formed by cutting the plating layer.

FIG. 13 shows a spacer 1301 which can be divided into four parts.
It is a layout of a, 1301b, 1301c, 1301d. Each spacer that can be divided has 1301e, 13
01f, 1301g, and 1301h have a convex portion with a radius of curvature of 2 mm at the tip. An optical element in which a resin layer having a Fresnel shape was adhered on the surface of a glass substrate was produced in the process shown in FIG. 3 using the mold and the spacer.

In FIG. 3, 302 is a light energy curable resin before curing, 303 is a spacer, and 306 is a release pin connected to a driving device (not shown). First, install a spacer 303 that can be divided into four on the mold 301,
Next, the light energy curable resin 302 was dropped (FIG. 3).
(A)). A glass base material 304 is placed on it 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 spacer 303 determines the resin thickness and the convex portion of the outer circumference (the tip has a radius of curvature of 2 mm) (FIG. 3).
(B)), UV light is irradiated to cure the resin (FIG. 3).
(C)).

When the curing is completed, the spacers 303 which can be divided into 4 are pulled out, and 101c, 101d, 101e,
The four glass parts outside the 101f part were released from the mold while increasing the pressure (FIG. 3 (d)). First, the tip of the 101c part started to release at about 20 kN, and when 20 kN was maintained as it was, the 101d, 101e, and 101f parts began to release at about 25 kN from the edge of the tip. Immediately after the peeling was started at each of the convex portions, the load was once reduced to stop the peeling, and when the peeling was started at all four positions, the load was applied again to start the mold release from the four positions at the same time. Then, the four parts started to be released at 15 kN, and the entire surface was released at 15 kN in about 5 seconds.

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.

No change was observed in the mold after repeated molding of 1000 shots.

Example 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 example, and FIG. 14 is a spacer used in this example. And FIG. 6 is a schematic view showing a method for manufacturing an optical element in this embodiment.

In FIG. 4, 401 is a light energy curable resin, and 402 is a glass base material. On the surface of 401, fine irregularities transferred by the mold are formed. The outer circumference is convex like 401a. This molded product was produced using the mold shown in FIG. FIG. 5 shows a mold having a sawtooth-shaped cross section with a maximum depth of 7 μm formed by photolithography and etching using a gray mask on quartz.
a is a Fresnel-shaped trough, and 501b is a Fresnel-shaped peak.

FIG. 14 shows a spacer 1401 which can be divided into two parts.
It is a layout of a, 1401b. Spacer 1401a
Has a convex portion with a radius of curvature of 2 mm like 1401c. The mold 501 and the spacer 1401
Using the above, a diffraction grating having fine irregularities on the surface was produced in the step shown in FIG.

In FIG. 6, 602 is a light energy curable resin before curing, 603 is a spacer, and 606 is a release pin connected to a driving device (not shown). First, install a spacer 603 that can be divided into two on the mold 601.
Next, the light energy curable resin 602 was dropped (FIG. 6).
(A)). A glass substrate 604 is placed on it and pressed by a device (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 spacer 603 determines the resin thickness and the convex portion of the outer circumference (the tip has a radius of curvature of 2 mm) (FIG. 6).
(B)), a light energy curable resin 6 by irradiating with UV light
02 is cured (FIG. 6C).

When the curing is completed, the spacer 603 which can be divided into two parts is pulled out, and the end portion of the glass substrate is released by the release pin 606.
Then, the pressure was gradually increased to release the mold (FIG. 5 (d)).
The tip 401b of the convex portion 401a started to be released at about 25 kN, and the entire surface was released at 25 kN for about 10 seconds.

In the light energy curable resin having the diffraction grating formed on the surface thus molded, the resin and the glass substrate were not separated from each other, and the edge portion of the grating was not chipped or deformed.

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

[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. 15 is a spacer used in this embodiment. And FIG. 3 is a schematic view showing a method of manufacturing an optical element in this embodiment.

In FIG. 7, 701 is a light energy curable resin and 702 is a glass substrate. Surface 7 of 701
Fresnel shapes transferred by a mold are formed on 01a and b (701a is a ridge portion (mountain portion in cross section),
1b is a valley (valley in the cross-sectional view). The outer periphery of the molded optical element is convex like 701c, 701d, 701e, and 701f. This molded product was produced using the mold shown in FIG.

Reference numeral 801 in FIG. 8 is a mold having Fresnel shapes 801c and 801d (801c is a valley portion (trough portion in cross section), 801d is a ridge portion (ridge portion in cross section)) having a maximum depth of 40 μm on the surface. On the phosphor bronze base material 801a, 100 μm of KN plating was applied, and the plating layer was cut to form Fresnel shapes 801c and 801d.

FIG. 15 shows a spacer 1501 which can be divided into four parts.
It is a layout of a, 1501b, 1501c, 1501d. Each spacer that can be divided has 1501e, 15
01f, 1501g, and 1501h, the tip has a convex portion with a radius of curvature of 2 mm. An optical element in which a resin layer having a Fresnel shape was adhered on the surface of a glass substrate was produced in the process shown in FIG. 3 using the mold and the spacer.

In FIG. 3, 302 is a light energy curable resin before curing, 303 is a spacer, and 306 is a release pin connected to a driving device (not shown). First, install a spacer 303 that can be divided into four on the mold 301,
Next, the light energy curable resin 302 was dropped (FIG. 3).
(A)). A glass base material 304 is placed on it 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 spacer 303 determines the resin thickness and the convex portion of the outer circumference (the tip has a radius of curvature of 2 mm) (FIG. 3).
(B)), UV light is irradiated to cure the resin (FIG. 3).
(C)).

When the curing is completed, the spacer 303 which can be divided into four parts is pulled out, and 701c, 701d, 701e, 7
The four glass parts outside the 01f part were released from the mold while increasing the pressure (FIG. 3 (d)). First, the tip of the 701c portion starts to release at about 20 kN, and if 20 kN is maintained as it is, the 701d, 701e, and 701f portions start to release at about 25 kN from the edge portion of the tip. Immediately after starting peeling at each of these protrusions, the load is once reduced to stop peeling,
When peeling was started at all four points, a load was applied again to start releasing from four points at the same time. Then, the four parts started to be released at 15 kN, and the entire surface was released at 15 kN in about 5 seconds.

The light energy curable resin having the Fresnel shape 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 lattice.

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

[Embodiment 4] FIG. 9 is a schematic view showing a method for manufacturing an optical element in this embodiment, and the molding was carried out in the same manner as in Embodiment 1 except using a mask. An optical element in which a resin layer having a Fresnel shape was adhered on the surface of a glass substrate was produced in the step shown in FIG. 9 using the mold.

In FIG. 9, 902 is a light energy curable resin before curing, 906 is a mask, and 903 is a release pin connected to a driving device (not shown). First, the mold 90
1 onto which a light energy curable resin 902 is dropped (see FIG.
(A)), a glass substrate 904 is placed on it, 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 release pin 903 which also serves as a spacer (FIG. 9B), the UV light is masked 9
Irradiate through 06 to cure the resin. The mask 906 has a shape as shown in FIG. 16 when viewed from above,
Convex portions 1601a and 1601 whose tip has a radius of curvature of 2 mm
b 1601c and 1601d, and 1601e does not transmit light, so the 1601e portion (hatched portion) of the resin remains uncured (FIG. 9C).

Although not shown, the release pin is once lowered and the uncured portion is washed away with acetone. The glass part was released by gradually increasing the pressure with a release pin (Fig. 9).
(D)). First of all, the tip of 101c part is 23k.
When the mold starts to be released at about N and remains at 23 kN,
The parts 101d, 101e, and 101f started to be released from the edge part of the tip thereof at about 23 kN. Immediately after the peeling was started at each of the convex portions, the load was once reduced to stop the peeling, and when the peeling was started at all four points, the load was applied again to start the release from the four points at the same time. Then, at 4 places, 18k
The mold release was started with N, and the entire surface was released with 18 kN in about 8 seconds.

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 edge portions of the lattice were not chipped or deformed.

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

[Embodiment 5] FIG. 10 is a schematic view showing a method for manufacturing an optical element in this embodiment, which was molded in the same manner as in Embodiment 1 except that a heat energy curable resin was used.

In FIG. 10, 1002 is a heat energy curable resin before curing, 1003 is a spacer, 1007.
Is a heater and 1006 is a release pin connected to a driving device (not shown). First, a spacer 1003 that can be divided into four parts is installed on the mold 1001, and then a thermal energy curable resin 1002 is dropped (FIG. 10A), and a glass base material 1004 is placed on the spacer 1003 by an apparatus (not shown). Pressurize.
A silane coupling agent is applied to the contact surface of the glass base material used with the resin for improving the adhesion. A silane coupling agent is applied to the contact surface of the glass base material used with the resin for improving the adhesion. And spacer 1
In 003, the resin thickness and the convex portion on the outer circumference (the tip has a radius of curvature of 2 m
m) is determined (FIG. 10B), the heater 100
Then, the temperature of the mold is kept constant at 80 ° C. for 30 minutes to cure the resin (FIG. 10C).

When the curing is completed, the spacer 1003 which can be divided into four parts is pulled out, and 101c, 101d, 101
The four glass parts outside the e and 101f parts were released from the mold while increasing the pressure (FIG. 10 (d)). First of all, 101
The tip of part c begins to release at about 21 kN,
When kN was maintained, the 101d, 101e, and 101f parts began to release from the edge part at the tip thereof at about 25 kN. Immediately after the peeling was started at each of the convex portions, the load was once reduced to stop the peeling, and when the peeling was started at all four positions, the load was applied again to start the mold release from the four positions at the same time. Then 4
All parts started to release at 16kN, then 9k at 16kN
The entire surface was released in about 2 seconds.

Also, this time, a heater built in the mold as a heat energy source is shown. However, as shown in FIG. 10C, an oven, a hot plate, etc. can be used for the mold, the resin and the spacer set. The same amount of heat energy may be added at.

The light energy curable resin having a Fresnel shape 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 lattice.

The mold did not show any change after repeated 1000 shots of molding.

[0054]

As is apparent from the above description, according to the present invention, the molded product has a convex portion in the outer peripheral portion when viewed from the direction perpendicular to the surface of the base material. The mold release force at the start can be reduced, and the mold release start point and mold release direction can be controlled, and it is possible to improve the durability of the mold by preventing the resin from peeling, deforming or breaking from the glass substrate. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an optical element in Examples 1, 4, and 5.

FIG. 2 is a schematic view showing a mold used in Examples 1, 4, and 5.

FIG. 3 is a schematic view showing a method for manufacturing an optical element in Examples 1 and 3.

FIG. 4 is a schematic view showing an optical element in Example 2.

5 is a schematic view showing a mold used in Example 2. FIG.

FIG. 6 is a schematic view showing a method for manufacturing an optical element in Example 2.

FIG. 7 is a schematic view showing an optical element in Example 3.

FIG. 8 is a schematic view showing a mold used in Example 3.

FIG. 9 is a schematic view showing a method for manufacturing an optical element in Example 4.

FIG. 10 is a schematic diagram illustrating a method for manufacturing an optical element in Example 5.

FIG. 11 is a schematic view showing an optical element according to the present invention.

FIG. 12 is a schematic view showing a cross section of a structure including a spacer.

FIG. 13 is a schematic view showing the arrangement of spacers in Examples 1, 4, and 5.

14 is a schematic view showing the arrangement of spacers in Example 2. FIG.

FIG. 15 is a schematic diagram showing the arrangement of spacers in Example 3.

FIG. 16 is a schematic view showing a mask used in Example 4.

[Explanation of symbols]

101,305,401,605,701,905,1005 Energy-curing resin after molding and curing 102,304,402,604,702,904,1004 Glass substrate 201,301,501,601,801,901,1001 Mold 303,603,1003,1203,1301,1401 Spacer 302,602,902,1002 Energy-curing resin before hardening 306,606,100,1160,1601,9031,1006 heater

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 11:00 B29L 11:00 F term (reference) 2H049 AA04 AA14 AA40 AA43 AA45 AA63 4F202 AA44 AH73 CA01 CB01 CM02 CM90 4F204 AA36 AA44 AD04 AH73 AH75 AH79 EA03 EA04 EB01 EB11 EF01 EF05 EK13 EK17 EK18 EK25

Claims (5)

[Claims] 1. An energy-curable resin having a required shape on a substrate by dropping an energy-curable resin into a mold, setting a substrate on the mold, applying energy to the resin to cure the resin, and releasing the resin. An optical element in which a mold resin is formed, wherein an outer peripheral portion of the molded product has a portion having a convex shape when viewed in a direction perpendicular to the surface of the base material. 2. An energy-curable resin having a desired shape on a substrate by dropping an energy-curable resin onto a mold, placing a substrate on the resin, applying energy to the resin to cure the resin, and releasing the resin. A method of manufacturing an optical element, comprising forming a mold resin, wherein a convex portion is used as a mold release starting point. 3. The method for manufacturing an optical element according to claim 2, wherein light energy is applied to the light energy curable resin to cure the resin. 4. The masking process is applied to the outer peripheral portion to cure the convex portion and the central portion adjacent to the convex portion, leave the other portion in an uncured state, and remove the uncured portion. Of manufacturing optical element of. 5. The method of manufacturing an optical element according to claim 2, wherein heat energy is applied to the heat energy curable resin to cure the resin.