JPH0924522A - Method and apparatus for manufacturing composite optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a composite optical element capable of completely preventing the mixture of bubble with a resin part. SOLUTION: In the case of manufacturing a composite optical element of the structure that a resin layer is connected to a glass base material, the steps of pouring resin monomer 8 in a liquid droplet state to the surface of the base material 4 and/or the molding surface of a mold member 1, and then evacuating in vacuum at least the space 7 between the base material and the mold member are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a composite optical element having a resin layer bonded to a surface of a glass substrate.

[0002]

2. Description of the Related Art In recent years, as lenses used in optical systems such as cameras and video cameras, aspherical lenses have been used for the purpose of reducing the number of lenses and making the optical system compact. The aspherical lens is a general term for lenses whose surface shape is deviated from a spherical surface, and the surface shape is an aspherical surface in order to remove spherical aberration generated in the spherical lens. The aspherical lens includes a plastic aspherical lens (plastic molded lens) and a glass aspherical lens (glass molded lens), and a composite type having a structure in which a thin aspherical resin layer is bonded to the surface of the spherical glass lens. An aspherical lens has been developed and is generally called a replica lens.

Such a replica lens is shown in FIGS.
As shown in 0, the mold member 1 precisely machined into a desired aspherical shape and the spherical glass lens 5 having a curvature close to this aspherical shape are placed in contact with each other, and either the spherical glass lens or the mold member is placed. Liquid resin monomer 8 is injected into the central portion of one of the surfaces (FIG. 7), and then the mold member 1 and the spherical glass lens 5 are brought close to each other so that the resin monomer 8 is brought into contact with the surface of the spherical glass lens 5. The resin monomer 8 is polymerized and cured after being contacted with and developed (FIGS. 8 and 9), and finally the interface between the mold member 1 and the cured resin monomer 8 is peeled off (FIG. 10).

The positional relationship between the mold member 1 and the spherical glass lens 5 differs depending on the lens shape. For example, in the case of a concave lens, the position of the resin droplet is more stable when the mold is arranged on the lens. Further, in the case of a convex lens, the position of the resin droplet is more stable when the lens is arranged on the mold. However, as long as the positional stability of the resin droplets is sufficient, the vertical relationship between the mold and the lens may be either.

In the general method of manufacturing the above-mentioned replica lens, there is a basic problem that bubbles are easily mixed in the resin material. The inclusion of bubbles is a serious problem because it significantly reduces the product yield of replica lenses and causes an increase in manufacturing cost.

The inclusion of air bubbles in the resin layer occurs when the resin monomer is injected into the center of the mold member or the glass base material and when the resin is brought into contact with the surface of the glass base material and expanded.

As a method for reducing air bubbles when injecting a resin monomer, the resin injection nozzle is brought as close as possible to the injection surface to slowly inject, and the injection nozzle is kept away from the injection surface after the resin comes into contact with the injection surface. A method of injecting a resin has been proposed (JP-A-4-78505 and JP-A-5-8231).

Further, as a method of reducing air bubbles when the resin is contact-developed on a glass surface or the like, a method has been proposed in which the approach speed between the mold and the base material is slowed to sufficiently slow the resin development speed. (JP-A-5-8231 and JP-A-4-231)
78505).

[0009]

However, any of the above-mentioned methods for reducing air bubble inclusion can reduce air bubble inclusion stochastically, but cannot completely eliminate it. Therefore, there is a problem in that the yield is low and it is necessary to check for air bubble inclusion by 100% inspection, resulting in high cost.

Further, in order to uniformly spread the resin and prevent air bubbles from being mixed in at the time of developing the resin, it is necessary to use a mold material which does not have a bad wettability with the resin monomer. However, when a mold material having good wettability is used, the contact angle of the resin monomer becomes large and the resin droplets are flattened. As a result, when the resin comes into contact with the resin, the first contact occurs from a plurality of points, so that air bubbles are easily mixed.
In this way, with the flattened resin droplets, no matter how slow the contact speed is, it is not possible to prevent the inclusion of bubbles at the time of resin contact. When the lens has a large diameter, the amount of resin increases and the resin droplets are flattened, so that bubbles are more likely to be mixed.

Note that these circumstances are the same for other complex type optical elements other than the replica lens.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method and an apparatus for manufacturing a composite optical element capable of completely preventing air bubbles from being mixed into a resin portion.

[0013]

In order to achieve the above object, a method for producing a composite optical element according to the present invention comprises a step of bringing a glass substrate and a molding surface of a mold member into contact with each other, and With the resin monomer droplets placed on at least one of the molding surfaces, the glass base material and the mold member are brought close to each other, the resin is spread on the glass base material surface, and then the resin layer is polymerized and cured. In the method for producing a composite optical element having a structure in which a resin layer is bonded to the glass base material by further peeling the resin from the mold member, a resin monomer is formed on the glass base material surface and / or the molding surface of the mold member. After injecting in the form of droplets, at least the space between the glass substrate and the mold member is evacuated.

The method for producing a composite optical element according to the present invention is the same as the method for producing a composite optical element, wherein the resin monomer injected in the form of droplets contacts both the glass substrate surface and the molding member molding surface. At that time, the vacuum state is released and the resin is developed.

Further, in the apparatus for producing a composite type optical element of the present invention, the mold member is disposed such that the molding surface is in contact with the bonding surface of the glass base material, and the horizontal position of the glass base material and the mold member. Means for matching, means for supplying droplets of a resin monomer to the glass substrate surface and / or the molding surface of the mold member, and means for bringing the glass substrate and the mold member close to each other and spreading the resin on the glass substrate surface And a means for supplying the resin layer with energy necessary for polymerizing and curing the resin, in a composite optical element manufacturing apparatus comprising: a means for sealing at least a space between the glass base material and the mold member; A means for evacuating the closed space between the material and the mold member is provided.

In the composite optical element manufacturing apparatus of the present invention, in the composite optical element manufacturing apparatus, the sealing means includes a wall member that encloses a space between the glass substrate and the mold member in a sealable manner. The airtight seal member is provided at a contact portion between the glass base material and the wall material and / or a contact portion between the mold member and the wall material or a gap portion.

[0017]

In the present invention, at least the space between the glass substrate and the mold member is evacuated after the resin monomer is injected, so that even if bubbles are mixed in the resin at the time of resin injection, it is removed. Since it is a vacuum, it is possible to completely prevent air from being entrapped in the resin layer.

Further, when the resin is expanded in a vacuum state, the dissolved gas in the resin monomer may appear as bubbles, but by returning to the atmospheric pressure before the resin expansion, the newly generated low pressure Bubbles can be crushed by atmospheric pressure.

Further, the manufacturing apparatus of the present invention can evacuate only the space between the glass substrate and the mold member.
Therefore, compared with the case where the entire apparatus is evacuated, it is possible to evacuate and release the vacuum in an extremely short time, and it is possible to avoid a decrease in manufacturing efficiency due to the evacuation process.
Further, since it is not necessary to put the entire apparatus in a vacuum container, the glass lens can be easily replaced, and automation by a robot or the like is easy.

The present invention will be described in detail below.

First, the invention of the manufacturing method will be described.

In the present invention, the glass substrate and the molding surface of the mold member are brought into contact with each other, and the droplet of the resin monomer is placed on at least one of the glass substrate surface and the molding surface of the mold member. In this state, the glass base material and the mold member are brought close to each other to spread the resin on the surface of the glass base material.

Here, the material, shape, etc. of the glass substrate are appropriately selected and designed according to the intended optical element. For example, the glass substrate is not particularly limited as long as it is glass that satisfies the required optical characteristics. Further, the shape of the glass substrate is not particularly limited, and those having a shape suitable for various optical elements such as a plate shape, a lens shape and a prism shape are used. The size of the glass substrate is not particularly limited, but the present invention enables the production of large-sized composite optical elements such as large-diameter lenses.

The surface of the glass substrate has a high adhesive strength,
For purposes such as improving the wettability of the surface, if necessary,
Silane coupling treatment, vapor deposition treatment, resin coating treatment, cleaning treatment and the like may be performed.

The mold member has a molding surface for shaping the resin layer bonded to the glass substrate into a desired shape. The molding surface of the mold member is mirror-finished into a desired aspherical shape or the like by precision processing or the like. The molding surface of the mold member may be subjected to a mold release treatment with a mold release agent or the like in order to facilitate the peeling after molding. The wettability of the molding surface of the mold member with respect to the resin monomer is preferably slightly worse than that of a general metal surface. As the material of the mold member, various metal materials, glass, ceramics, polymer materials and the like are used.

The resin is supplied by a dispenser, a syringe,
Use a precision dispenser.

The resin is supplied to the surface of the glass base material, the molding surface of the mold member, or both surfaces thereof, if necessary. At this time, the resin supply speed, the nozzle position, the distance between the nozzle tip and the resin supply surface, the resin viscosity, etc. are appropriately adjusted so that the resin monomer becomes droplets. From this viewpoint, the viscosity of the resin is preferably about several thousand cP (centipoise). Before supplying the resin, it is preferable to sufficiently remove bubbles and dissolved gas in the resin under vacuum (under reduced pressure).

The resin used is an energy curable resin,
Any polymerizable resin such as a heat-polymerizable resin may be used, and the polymerization method may be a method suitable for the resin.

Specific examples of the resin include urethane acrylate resin, urethane methacrylate resin, urethane modified acrylate resin, epoxy acrylate resin, epoxy methacrylate resin, acrylic resin, epoxy resin, and other optical resins and curing. Mold optical resin compositions and the like can be mentioned.

These resins are polymerizable (including crosslinkable)
It may be any form of a monomer (monofunctional monomer, polyfunctional monomer), oligomer (prepolymer), polymer (polyurethane (meth) acrylate, etc.).

As the urethane (meth) acrylate,
Ugaku Co., Ltd.), U-4HA (Shin Nakamura Chemical Co., Ltd.)
It can also be used by selecting from various commercially available urethane (meth) acrylate resins (commercially available), such as UV curable resins, optical adhesives, and resin modifiers.

These resins may be used alone or in combination of two or more. in this case,
It is preferable to use a combination of resins that hardly generate bubbles.

Examples of other additive components in the optical resin layer include a polymerization initiator and a diluting resin component.

The polymerization initiator is added to the resin as needed. Polymerization with a polymerization initiator can be initiated by light polymerization, thermal polymerization, radiation polymerization or the like. As the photopolymerization initiator, benzophenone, benzoin ethyl ether, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-chlorothioxazoline, p
As the thermal polymerization initiator such as ethyl dimethylaminobenzoate, cumene hydroxyperoxide, benzoyl peroxide, azobisisobutyronitrile, azobisdimethylvaleronitrile and the like can be used.

Examples of the diluting resin component include photocurable monomers such as methyl acrylate and ethyl acrylate.

After the resin is supplied, the glass base material and the molding surface of the mold member are aligned with each other. As the alignment means, a known method such as an optical axis alignment mechanism is used.

In the present invention, after the resin is supplied, at least the space between the glass base material and the mold member is evacuated. Here, it is preferable that the degree of vacuum (pressure at the time of depressurization) is appropriately set according to the type and characteristics of the resin, and the bubbles mixed during the resin injection are sufficiently removed.

Usually, the time required to remove air bubbles while keeping the space around the resin under reduced pressure is within 1 minute. Also,
It is sufficient that the pressure during depressurization is about 10 ^-3 to 10 ^-1 torr.

A known vacuum pump such as a rotary pump can be used for evacuation.

After evacuation, the glass base material and the mold member are brought close to each other to bring the droplets of the resin monomer into contact with the mold member molding surface or the glass base material surface. In the present invention, when the resin is in contact with the resin layer, a vacuum around the resin can completely prevent air from being entrapped in the resin layer.

After contact with the resin monomer droplets, the vacuum state is released, the glass base material and the mold member are brought closer to each other, and the resin is developed.

It is easier to control the vacuum release timing by releasing the vacuum state by temporarily stopping the approach of the glass substrate and the mold member after contact with the resin monomer droplets, but the approach speed is sufficient. When the speed is low, the vacuum may be released while approaching. The gas introduced for releasing the vacuum may be air, but when oxygen in the air hinders the polymerization of the resin, it is desirable to use an inert gas or the like. The gas introduced for releasing the vacuum is preferably filtered to prevent inflow of dust, dust, oil mist and the like.

In order to release the vacuum state, it is not necessary to completely return it to the atmospheric pressure, and it is sufficient to reduce the degree of vacuum to the extent that new bubbles are not generated.

In the resin development, when the approaching speed of the glass base material and the mold member is slowed to slow the resin developing speed, the nonuniform spread of the resin is suppressed and the risk of entraining air during the resin developing is reduced. . In this case, the approaching speed of the glass base material and the mold member is preferably about 0.05 to 0.1 mm / sec.

After the development of the resin, the resin layer is polymerized and cured, and the resin is peeled off from the mold member to manufacture a composite optical element having a structure in which the resin layer is bonded to the glass base material.

If necessary, an antireflection film or the like is formed on the surface of the composite optical element.

Next, the invention of a manufacturing apparatus suitable for carrying out the above-described manufacturing method will be described.

As the manufacturing apparatus of the composite type optical element, various types and modes of apparatus are known, but the present invention can be applied to any apparatus.

The present invention provides, in a composite optical element manufacturing apparatus, means for sealing at least the space between the glass base material and the mold member, and means for vacuuming the sealed space between the glass base material and the mold member. It is characterized by being provided.

Here, the means for sealing the space between the glass base material and the mold member includes, for example, a wall material that encloses the space between the glass base material and the mold member in a sealable manner, and a glass base material and a wall material. And the airtight seal member provided in the contact portion between the mold member and the wall material or in the gap portion.

In this case, when the mold member and the wall material are integrally molded, the airtight seal member between the mold member and the wall material can be omitted. Further, when the glass base material holding member and the wall material are integrally molded, the airtight sealing member between the glass base material holding member and the wall material can be omitted. Instead, the glass base material holding member and the glass base material can be omitted. A seal member may be used for the contact portion of the material. As a material for the airtight seal member, a usual elastomer such as silicone rubber or natural rubber is preferable.

Normally, the glass base material holding means and the aligning means (optical axis aligning mechanism) are also used. However, for example, when the die is moved to perform the aligning, these may be configured separately. Good.

The range of the closed space for vacuuming is
It is desirable to make only the space between the mold member and the glass lens in terms of manufacturing efficiency, but even if a wider range is evacuated, similar effects can be expected except for the manufacturing efficiency.

As a means for evacuating the closed space between the glass substrate and the mold member, a vacuum pump known in various fields such as a rotary pump can be used.

Examples of means for supplying energy required for polymerization and curing of the resin to the resin layer include active energy ray irradiation devices such as an ultraviolet irradiation device and heating devices. These devices are used depending on the type of resin. Used as an option.

Means for bringing the glass base material and the mold member close to each other are as follows:
Either one of the glass substrate and the mold member may be configured by a mechanism that precisely drives in the vertical direction while maintaining the horizontalness of both, but in order to ensure the accuracy of the optical axis, the mold side is moved up and down. Is preferred.

In the manufacturing apparatus of the present invention, since the volume of the space between the glass base material and the mold member is small, it is easy to evacuate and release the vacuum, and the atmosphere of the space between the glass base material and the mold member, Control of conditions such as pressure is easy, and it is short-time and low-cost, and is suitable as a manufacturing apparatus that requires these controls.

The field of use of the method of the present invention is not limited to the replica lens, but can be applied to any composite optical element (including composite optical component) manufactured by bonding resin and glass. . Further, the device of the present invention can also be used as a molding device for various optical components which are reluctant to mix bubbles.

Specifically, for example, an optical lens such as a camera lens, a video camera lens, a photographic lens, a light source lens for optical communication, a spectacle lens, a pickup lens of a compact disc player, a large-diameter lens for a projection television, and the like. , Phase grating type low pass filter, color filter, phase grating filter, anamorphic lens, lenticular lens, grating,
It can also be used for minute composite optical elements such as prisms, zone plates, Fresnel lenses, and holographic lenses.

[0060]

Embodiments of the present invention will be described below.

FIG. 1 is a partial sectional view showing a main part of a replica lens manufacturing apparatus. As shown in FIG. 1, a cylindrical body 2 is coaxially mounted on a die 1 precision-machined to an aspherical surface. The body 2 is fixed to a support 12 and the die 1 is It is installed so that it can move up and down. A rubber O-ring 3 is mounted as an airtight seal member below the gap between the mold 1 and the body mold 2. Further, a rubber airtight seal member 4 is also joined to the upper end of the barrel die 2, and the rubber die airtight seal member 4 is brought into contact with the surface of the spherical glass lens 5 and the upper portion of the barrel die 2 is covered. By degassing from the vacuum port 6 on the side surface, only a small space 7 sandwiched between the glass lens 5 and the mold 2 can be evacuated. The vacuum state is released by introducing gas from the vacuum port 6. Next, the manufacturing method of the present invention using the manufacturing apparatus shown in FIG. 1 will be described.

A resin monomer mixed with a photopolymerization initiator is prepared in advance, the air bubbles and the dissolved gas in the resin monomer are sufficiently removed under vacuum, and then the resin monomer is filled in a dispenser for supplying resin. Next, after injecting the resin monomer 8 into the center of the upper part of the mold 1 with the dispenser, the spherical glass lens 5 is set on the upper part of the mold 1, and the optical axis alignment mechanism 9 aligns the optical axes of the mold 1 and the spherical glass lens 5. (Fig. 1).

Next, a vacuum is drawn from the vacuum port 6 of the barrel die 2 to remove the bubbles mixed by the resin injection. Unlike dissolved gas, bubbles mixed during resin injection can be removed immediately.

Next, the mold 1 and the spherical glass lens 5 are brought close to each other at a low speed, and immediately after the resin droplet comes into contact with the spherical glass lens 5, an inert gas or the like is introduced from the vacuum port 6 to release the vacuum state. (Fig. 2). This is because even in the case of a resin from which dissolved gas has been sufficiently removed, bubbles may rarely be generated due to new contact with the mold or glass lens surface in a high vacuum state. Therefore, immediately after the resin droplet comes into contact with the spherical glass lens 5, it is possible to prevent the generation of new bubbles by returning the atmospheric pressure to the atmospheric pressure, and the bubbles having a low atmospheric pressure generated before the vacuum is released are crushed by the external pressure. be able to.

After releasing the vacuum, the mold 1 and the spherical glass lens 5 are again brought close to each other at low speed, and the resin 8 is spread over the entire surface of the glass lens (FIG. 3).

Then, active energy rays are irradiated from the glass lens side to polymerize and cure the developed resin. After the resin is polymerized and cured, the lens is peeled off from the mold, so that a bubble-free replica lens can be manufactured.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments.

For example, as the optical axis adjusting mechanism 9 shown in FIGS. 1 to 3, a three-point outer diameter collision method as shown in FIGS. 4 (a) and 4 (b), a bell chuck method as shown in FIG. A known optical axis adjusting mechanism of can be used.

When the bell chuck method is adopted as the optical axis alignment method, the bell chuck 10 has a cylindrical shape as shown in FIG. In this case, the lower part of the gap between the die 1 and the cylindrical bell chuck 10 is sealed with the rubber seal member 3, and the vacuum port 6
May be provided on the side surface of the bell chuck 10. However, the rubber seal on the tip of the bell chuck may deteriorate the accuracy of the optical alignment of the bell chuck itself, so
The rubber seal member at the tip of the bell chuck needs to be a rubber seal member 11 that is pressed (attached) to the tip of the bell chuck only when vacuuming, as shown in FIG. 6, for example.

[0070]

As described above, according to the method for producing a composite optical element of the present invention, it is possible to reliably produce a composite optical element having no bubbles in the resin layer.

Even with a large-diameter composite optical element, it is possible to reliably manufacture a composite optical element having no bubbles in the resin layer.

Further, according to the apparatus for producing a composite optical element of the present invention, it is possible to evacuate and release the vacuum in an extremely short time, and to efficiently and reliably provide a composite optical element having no bubbles in the resin layer. It can be reliably manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a basic configuration and a manufacturing procedure of a manufacturing apparatus for a composite optical element according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining the next operation and manufacturing process of the manufacturing apparatus shown in FIG.

FIG. 3 is a cross-sectional view for explaining still another operation and manufacturing process of the manufacturing apparatus shown in FIG.

4A and 4B are views for explaining a three-point outer diameter collision method in the optical axis alignment method, in which FIG. 4A is a plan view and FIG.
FIG. 4 is a sectional view taken along line AA of FIG.

FIG. 5 is a sectional view for explaining a bell chuck method in an optical axis alignment method.

FIG. 6 is a schematic cross-sectional view showing a manufacturing apparatus when the bell chuck is substituted for a body mold.

FIG. 7 is a cross-sectional view for explaining a manufacturing procedure for a conventional general composite optical element.

FIG. 8 is a cross-sectional view for explaining the next manufacturing step after FIG.

FIG. 9 is a cross-sectional view for explaining the next manufacturing step after FIG.

FIG. 10 is a cross-sectional view for explaining the next manufacturing step after FIG.

[Explanation of symbols]

 1 Mold 2 Body 3 Rubber O Ring 4 Rubber Seal Member 5 Glass Lens 6 Vacuum Port 7 Space Between Glass Lens and Mold 8 Resin Monomer 9 Optical Axis Alignment Mechanism 10 Bell Chuck 11 Rubber Seal Member 12 Support Stand

Claims (4)

[Claims] 1. A glass substrate and a molding surface of a mold member are brought into contact with each other, and a droplet of a resin monomer is placed on at least one surface of the glass substrate surface and the molding surface of the mold member. , The glass base material and the mold member are brought close to each other, the resin is spread on the surface of the glass base material, the resin layer is polymerized and cured, and the resin is peeled off from the mold member to bond the resin layer to the glass base material. In a method of manufacturing a composite optical element having a structure, after injecting a resin monomer in the form of droplets onto the surface of a glass base material and / or the molding surface of a mold member, at least the space between the glass base material and the mold member is evacuated. A method for manufacturing a composite optical element, characterized by comprising steps. 2. The method for producing a composite optical element according to claim 1, wherein the vacuum state is released when the resin monomer injected in the form of droplets contacts both the glass substrate surface and the mold member molding surface. A method for manufacturing a composite optical element, which comprises developing a resin. 3. A means for holding a glass base material, a mold member arranged such that a molding surface is in contact with a bonding surface of the glass base material, and the glass base material and the mold member are aligned in the horizontal direction. A means for supplying droplets of a resin monomer to the glass substrate surface and / or the molding surface of the mold member; a means for bringing the glass substrate and the mold member close to each other and developing the resin on the glass substrate surface; A device for manufacturing a composite optical element, comprising means for supplying energy required for polymerization and curing of a resin to the layer, means for sealing at least a space between the glass base material and the mold member, and the glass base material and the mold. An apparatus for manufacturing a composite optical element, which is provided with means for evacuating a closed space between members. 4. A wall means for sealingly enclosing a space between a glass base material and a mold member, a contact portion between the glass base material and the wall material, and / or a contact portion between the mold member and the wall material. Alternatively, the apparatus for manufacturing a composite optical element according to claim 3, characterized by comprising an airtight seal member provided in the gap.