JP2003019716A - Mold for holding composite lens and method for molding composite lens by using the mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a precision composite lens by improving the release properties of a mold for molding the lens. SOLUTION: In a method for molding the composite lens, in the mold 1 for molding the composite lens, a mold main body 11 has a mold surface 11a on which a transfer shape for constituting the shape of a resin lens is formed. At least a photocatalyst effect film 12 is formed on the mold surface 11a. An ultraviolet curable resin is arranged between the mold surface 11a and a lens to be a base material. After that, the ultraviolet curable resin and the mold surface 11a are irradiated with ultraviolet rays so that the resin is hardened to form the resin lens. The resin lens, which has acquired the photocatalyst effect of the film 12 on the mold surface 11a, is peeled off from the mold surface 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a molding die for a compound lens and a molding die thereof for forming an aspherical lens by forming a resin lens on the surface of a lens serving as a base material such as a glass lens. The present invention relates to a method for molding a compound lens.

[0002]

2. Description of the Related Art In recent years, aspherical lenses have been widely used in optical electronic devices such as digital still cameras and digital video cameras for downsizing and high image quality. This aspherical lens is roughly classified into a glass aspherical lens and a resin aspherical lens.

The aspherical glass lens is formed by directly grinding each lens, or by a "mold" in which a material is heated to a glass transition point or higher and is molded with a mold having an aspherical shape. Manufactured by the law. In either manufacturing method, the cost of the aspherical lens is considerably higher than that of the spherical lens.

On the other hand, resin aspherical lenses are manufactured by the "injection molding method" in which a resin is thermoplastically molded. The resin aspherical lens can be manufactured at a lower cost than the glass aspherical lens, but has less variation in the refractive index of the resin material and has a small degree of freedom.

Therefore, a composite aspherical lens having the advantages of both the glass aspherical lens and the resin aspherical lens has been considered. The compound aspherical lens is an optical lens in which an aspherical layer made of resin is formed on the surface of a glass spherical lens that can be processed at low cost.

In the case of manufacturing this composite aspherical lens, an ultraviolet (UV) curable resin is applied to a glass material which is a base material formed in advance by polishing or the like, and a mold having an aspherical shape is applied thereon. Use it to transfer it to the desired shape on the resin and UV
The mold is peeled off (released) while the resin is solidified by irradiating light.

[0007]

However, in the production of such a composite aspherical lens, when the mold is released after fixing the resin, the resin is fused to the mold and the resin is There is a problem that a desired aspherical shape cannot be obtained due to mold release strain even if it remains on the surface or does not remain.

For this reason, a method has been adopted in which a mold-releasing property is enhanced by applying a mold-releasing agent such as silicon or fluorine to the surface of the mold. However, in this case, the release agent is transferred to the resin side, which causes a problem that the adhesion of the film cannot be ensured when an antireflection film or the like is applied on the resin as a post-treatment.

A method of improving the releasability by previously kneading the UV-curable resin with a release agent is also conceivable.
Similar to the above, in addition to failing to secure the adhesion of a film such as an antireflection film, there is a problem that the resin becomes cloudy in a long-term environmental test.

[0010]

The present invention has been made to solve the above problems. That is, the present invention provides a compound lens molding die for forming a resin lens on the surface of a lens serving as a base material, in which the die body is provided with a die surface on which a transfer shape of the resin lens is formed. At least the photocatalytic effect film is formed on the surface of the mold.

In the present invention as described above, since the photocatalytic effect film is formed on the mold surface forming the shape of the resin lens, the resin lens after molding is formed by the photocatalytic reaction by the photocatalytic effect film without using a releasing agent. It becomes easy to peel from the mold surface.

Further, in a method of molding a composite lens in which a resin lens is formed on a surface of a lens serving as a base material by using a molding die, at least a mold surface of a molding die in which a transfer shape of the resin lens is formed in advance. A photocatalytic film is formed on the surface of the mold.Next, the UV irradiation curable resin is interposed between the mold surface and the lens serving as the base material, and then the UV irradiation curable resin and the mold surface are exposed to UV light. It is also a method of molding a composite lens in which the resin lens is peeled off from the mold surface while the photocatalytic effect of the photocatalytic film on the mold surface is obtained while the resin lens is formed by curing the ultraviolet irradiation curable resin by irradiation. .

In the present invention as described above, since the photocatalytic film is previously formed on the surface of the mold, the ultraviolet irradiation is performed with the ultraviolet irradiation curable resin interposed between the surface of the mold and the lens serving as the base material. By so doing, it is possible to solidify the ultraviolet radiation curable resin to form a resin lens and at the same time obtain a photocatalytic reaction by the photocatalytic film on the mold surface, so that the resin lens after curing can be easily peeled from the mold surface. Become.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating a molding die for a compound lens according to this embodiment. That is,
The molding die 1 is a metal mold, and is used to mold an aspherical resin lens on the surface of a glass spherical lens or the like serving as a base material.

A mold surface 11a for transferring a desired shape (for example, an aspherical shape) to the resin lens is provided on the surface of the mold body 11 facing the surface of the base lens.
The mold surface is processed into a transfer shape such as an aspherical surface by a precision lathe or the like, and a photocatalytic effect film 12 (titanium oxide, niobium oxide, etc.) having a photocatalytic effect is formed on the processed surface.

The photocatalytic effect film 12 can be formed by various manufacturing methods such as a vacuum deposition method, a sputtering method, an ion plating method and an ion assist method. Further, the thickness of the photocatalytic effect film 12 is set to a value at which a sufficient photocatalytic effect can be obtained and the shape of the mold surface 11a can be accurately transferred to the resin lens.

FIG. 2 is a schematic cross-sectional view for explaining the usage state of the molding die of this embodiment. Molding die 1 of the present embodiment
Is inserted into the frame die 2 as a jig in order to form the aspherical resin lens 21 at the correct position on the surface of the base lens L1. In this state, the ultraviolet radiation curable resin 20 is interposed between the mold surface 11a and the base lens L1, and the base lens L1 is held by the pressing die 3 while the ultraviolet light source 4 transmits the ultraviolet light through the base lens L1. The resin lens 21 is formed by irradiating light and hardening the ultraviolet irradiation curable resin 20 to transfer the aspherical shape of the mold surface 11a.

Since the photocatalytic film 12 is formed on the mold surface 11a of the molding die 1 of this embodiment, the photocatalytic effect is exhibited by the ultraviolet light emitted from the ultraviolet light source 4 through the base lens L1. Then, the base lens L1 after the resin lens 21 is formed can be easily separated from the molding die 1.

That is, by using the molding die 1 of the present embodiment, it is possible to apply a mold release agent to the mold surface 11a and to mix the mold release agent into the ultraviolet irradiation curable resin 20 which becomes the resin lens 21. , Molded resin lens 21 and mold surface 11
The resin lens 2 can be easily peeled off from a by a photocatalytic effect, and resin residue on the mold surface 11a can be eliminated.
It is possible to improve the adhesion of various films to the surface 1 and prevent clouding of the resin lens 21.

Next, a method of molding a compound lens using this molding die will be described. First, as shown in FIG.
A predetermined amount of the ultraviolet irradiation curable resin 20 in a soft state is potted or applied on the mold surface 11a (the surface on which the photocatalytic effect film 12 is formed) of the molding die 1 of the present embodiment.

Next, as shown in FIG. 3B, with the molding die 1 inserted in the frame die 2, the ultraviolet radiation curable resin 2 is introduced.
The base lens L1 is placed on top of 0. As a result, a predetermined gap between the surface of the base lens L1 and the mold surface 11a is filled with the ultraviolet irradiation curable resin 20.

Next, as shown in FIG. 3 (c), a pressing die is mounted on the base lens L1 and the base lens L1 is fixed, and ultraviolet rays are emitted from the ultraviolet light source 4 toward the base lens L1. Irradiate with light. This ultraviolet light is the base lens L
1, and reaches the ultraviolet irradiation curable resin 20, and reaches the photocatalytic effect film 12 on the mold surface 11a.

The ultraviolet light cures the ultraviolet irradiation curable resin 20 along the shape of the mold surface 11a, and exhibits the photocatalytic effect of the photocatalytic effect film 12. That is, it is possible to realize both the curing of the ultraviolet irradiation curable resin 20 and the photocatalytic effect of the photocatalytic effect film 12 by one irradiation of the ultraviolet light.

Next, as shown in FIG. 4A, the pressing die 3 is removed. After that, as shown in FIG. 4B, the base lens L1 having the resin lens 21 formed on the surface thereof, that is, the compound lens L is peeled (released) from the mold surface 11a of the mold body 11. In this mold release, since the photocatalytic effect of the photocatalytic effect film 12 is exhibited by the previous irradiation of ultraviolet light, the resin lens 21 and the mold surface 11a are easily peeled off,
The resin does not remain on the mold surface 11a and the resin lens 21 does not lose its shape, and the highly accurate compound lens L can be manufactured.

FIG. 5 is a schematic sectional view for explaining another embodiment. The molding die 1 is a die for forming a compound concave lens, and a convex die surface 11 obtained by transferring the shape of a resin lens formed on the surface of the concave lens is formed on the die body 11.
a is provided. Further, the photocatalytic effect film 12 is formed on the mold surface 11a as in the above.

FIG. 6 is a schematic sectional view for explaining the usage state of the molding die. The molding die 1 is arranged above the concave lens L2 previously arranged in the frame die 2 with the ultraviolet irradiation curable resin 20 interposed between the concave lens L2 and the surface of the concave lens L2. In this state, ultraviolet light is irradiated from the ultraviolet light source 4 through the concave lens L2, the ultraviolet irradiation curable resin 20 is solidified, and the aspherical shape of the mold surface 11a is transferred to form the resin lens 21.

In this molding die 1 as well, since the photocatalytic effect film 12 is formed on the die surface 11a as before,
The photocatalytic effect is exerted by the ultraviolet light emitted from the ultraviolet light source 4 through the base lens L1, and the base lens L1 after the resin lens 21 is formed can be easily separated from the molding die 1.

In other words, by using the molding die 1 of this embodiment, it is possible to apply a mold releasing agent to the mold surface 11a and to mix the mold releasing agent into the ultraviolet irradiation curable resin 20 which becomes the resin lens 21. , Molded resin lens 21 and mold surface 11
The peeling from a can be easily performed by the photocatalytic effect, the adhesion of various films to the surface of the resin lens 21 can be improved, and the cloudiness of the resin lens 21 can be prevented.

Next, a method of molding a compound lens using this molding die will be described. First, as shown in FIG.
A glass concave lens L2 having a spherical surface is used as a base lens, and a predetermined amount of a soft ultraviolet irradiation curable resin 20 is potted or applied to the concave surface of the concave lens L2.

Next, as shown in FIG. 7B, the concave lens L2 is housed in the frame mold 2 with the UV irradiation curable resin 20 potted or applied upward, and fixed at a predetermined position. Next, as shown in FIG. 7C, the molding die 1 of the present embodiment is placed on the concave lens L2 of the frame die 2. As a result, the mold surface 11a presses the ultraviolet irradiation curable resin 20 on the concave lens L2, and a predetermined gap between the concave lens L2 and the mold surface 11a is filled with the ultraviolet irradiation curable resin 20.

Then, in this state, the concave lens L2 is moved from the ultraviolet light source 4 arranged on the opposite side of the molding die 1 of the concave lens L2.
Irradiate ultraviolet light toward. UV light is concave lens L2
And reaches the ultraviolet irradiation curable resin 20, and reaches the photocatalytic effect film 12 on the mold surface 11a.

By this ultraviolet light, the ultraviolet irradiation curable resin 20 is cured along the shape of the mold surface 11a, and the photocatalytic effect of the photocatalytic effect film 12 is exhibited. That is, it is possible to realize both the curing of the ultraviolet irradiation curable resin 20 and the photocatalytic effect of the photocatalytic effect film 12 by one irradiation of the ultraviolet light.

Next, as shown in FIG. 8A, the molding die 1 is separated (released) from the frame die 2. In this mold release, the photocatalytic effect of the photocatalytic film 12 is exerted by the previous irradiation of ultraviolet light, so that the resin lens 21 and the mold surface 11a are easily peeled off, and the resin residue on the mold surface 11a and the resin lens 21 are removed. Highly accurate compound lens L that does not lose its shape
Will be able to manufacture.

Then, as shown in FIG. 8B, finally, the compound lens L is taken out from the frame mold 2 by vacuum suction or the like.

As described above, in any lens shape, the photocatalytic reaction by the photocatalytic film 12 on the mold surface 11a decomposes the resin at the interface where the photocatalytic film 12 and the resin lens 21 are fused. As a result, fusion with the mold surface 11a is released, and it becomes possible to perform molding with extremely good releasability.

Next, a specific example of this embodiment will be described. In this specific example, a case will be described in which a compound aspherical resin lens is formed on at least one of the surfaces through which light rays pass in a lens system that uses a CCD as an imaging system.

First, a method for producing the molding die 1 shown in FIG. 1 will be described. First, the surface of the stainless steel alloy is cut to a shape close to the shape to be finally finished. Next, electroless nickel plating is applied to the processed surface to a thickness of about 50 μm, and then the nickel plated layer is cut to a final aspherical shape with a precision lathe.

Next, a titanium oxide (TiO ₂ ) thin film is applied to the mold surface 11a of the molding die 1 thus manufactured by a vacuum vapor deposition method. In order to perform the vacuum vapor deposition method, the molding die 1 is subjected to necessary cleaning treatment in advance to remove impurities such as dust and cutting oil. After cleaning, the molding die 1 is set in the vacuum vapor deposition tank.

Then, after heating up to about 300 ° C. while raising the degree of vacuum, a desired thin film is formed by a vapor deposition method at a starting degree of vacuum of 5.0 × 10 ⁻⁶ hPa. That is, powder,
Pellet or granular titanium oxide (Ti0 ₂ ) was put into a crucible, this titanium oxide was heated by an electron beam method, and a physical film thickness of about 100 nm was obtained using a crystal type film thickness meter or an optical film thickness meter. Titanium oxide is formed with the following thickness.
Ti0 can also be used lower oxides of Ti or Ti to ₂ instead. In this case, the partial pressure is 8.0 if necessary.
It is also possible to supplement oxygen of about 10 ⁻⁵ hPa.

As the method of forming the photocatalytic effect film 12, not only the vacuum vapor deposition method but also the sputtering method, the ion plating method, the ion assist method, and the CVD method may be used.

After forming the titanium oxide film as described above, the inside of the vacuum vapor deposition tank is opened to the atmosphere and the sample (molding die 1) is taken out. Using the produced molding die 1, a composite aspheric surface is formed by the following method.

First, the refractive index nd = 1.
847 glass substrate (eg glass type: SFL5
7) is processed into a lens shape with a desired surface accuracy to form the base lens L1. The surface of the base lens L1 opposite to the surface on which the aspherical resin lens 21 is to be formed is subjected to predetermined cleaning as needed by a vacuum deposition method or the like in advance, and then an antireflection coating or the like is applied. Surface treatment.

Next, the ultraviolet irradiation curable resin 20 (nd = 1.54) is dropped in a fixed amount on the surface on which the resin lens 21 is to be formed. The amount of resin dropped at this time is set to such an extent that it does not run off the lens surface after the resin lens 21 is molded. After the resin is dropped, the resin is molded by the above-described molding die 1 so that the center thickness of the resin is 0.2 mm.

With the molding die 1 fixed in this state, ultraviolet light is irradiated for about 10 seconds to fix the ultraviolet irradiation curable resin 20 and activate the surface of the photocatalytic effect film 12. After the irradiation of ultraviolet light, the molding die 1 is released, and the compound lens L is taken out from the jig.

The mold releasability was compared between such a process and a process using a molding die having no conventional photocatalytic effect film. As a comparative example, those not subjected to mold surface treatment, those containing a release agent in the resin, those subjected to a silicon-based release agent instead of the photocatalyst layer, prepared,
Continuous molding was performed 1000 times under the same conditions.

The results are shown in FIG. As can be seen from FIG. 9, even when the compound aspherical lens is continuously molded according to this embodiment, the releasability is not impaired, no resin remains on the mold, and the antireflection film adhesion to the compound lens surface is also maintained. It is good and the lens appearance can be molded neatly. In addition, it is possible to provide a stable composite aspherical lens without causing cloudiness or the like in terms of long-term reliability.

On the other hand, in the comparative example, although the adhesion and long-term reliability of the antireflection film are good, the resin residue on the mold appears after 50 shots, and the compound lens has a resin appearance ( Distortion) was seen.

Further, in the comparative example, although the appearance of the compound lens is good, the resin residue on the mold is partially generated, the adhesion of the antireflection film is poor, and the cloudiness is generated in the long-term reliability. is doing.

Further, in the comparative example, although the resin remaining on the mold and the long-term reliability are good, the adhesion of the antireflection film is poor, and the appearance of the lens is also considered to be the residue of the release agent. There is cloudiness.

As described above, it can be seen that in this embodiment, good results can be obtained in terms of resin residue on the mold, adhesion of the antireflection film, appearance, and long-term reliability.

In the present embodiment, as the mold 1 for molding the compound lens, an example mainly composed of a metal mold has been described, but the present invention is not limited to this, and is made of another material such as a glass mold or a resin mold. Even a mold is applicable. Further, the glass lens is used as an example of the lens serving as the base material, but the same applies to a resin lens.

[0052]

As described above, according to the present invention,
By improving the releasability between the resin lens and the mold surface, it is possible to obtain a high-quality and stable compound lens with reduced distortion at the time of demolding. Further, since the release agent can be eliminated, it becomes possible to improve the adherence of various films to the surface of the complex lens after completion and to provide a high quality complex lens by eliminating clouding of the resin. Further, since good mold releasability can be obtained, cleaning of the mold surface becomes unnecessary, and the number of steps can be significantly reduced. This allows
It is possible to provide a high-performance compound lens at low cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating this embodiment.

FIG. 2 is a schematic cross-sectional view illustrating a usage state of a molding die.

FIG. 3 is a schematic cross-sectional view (No. 1) for explaining the molding method of the present embodiment.

FIG. 4 is a schematic cross-sectional view (No. 2) for explaining the molding method of the present embodiment.

FIG. 5 is a schematic cross-sectional view illustrating another molding die.

FIG. 6 is a schematic cross-sectional view illustrating a usage state of another molding die.

FIG. 7 is a schematic cross-sectional view (No. 1) for explaining a molding method using another molding die.

FIG. 8 is a schematic cross-sectional view (No. 2) for explaining a molding method using another molding die.

FIG. 9 is a diagram illustrating the present embodiment and a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Molding type, 2 ... Frame type, 3 ... Pressing type, 4 ... Ultraviolet light source, 11 ... Mold main body, 11a ... Mold surface, 12 ... Photocatalytic effect film, 20 ... UV irradiation curable resin, 21 ... Resin lens , L ... Compound lens, L1 ... Base lens, L2 ... Concave lens

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29L 11:00 G02B 1/10 Z F term (reference) 2K009 BB11 CC03 DD03 DD04 DD05 EE00 FF03 4F202 AA44 AH75 AJ01 AJ02 AJ09 CA01 CB01 CD22 CK11

Claims (2)

[Claims] 1. A compound lens molding die for forming a resin lens on the surface of a lens serving as a base material, wherein the die body is provided with a die surface on which a transfer shape of the resin lens is formed. A mold for molding a compound lens, wherein a photocatalytic film is formed on at least the mold surface. 2. A method of molding a composite lens, wherein a resin lens is formed on the surface of a lens serving as a base material by using a molding die, wherein at least a mold of a molding die in which a transfer shape of the resin lens is formed in advance. A photocatalytic film is formed on the surface, and then an ultraviolet irradiation curable resin is interposed between the mold surface and the lens serving as the base material, and then the ultraviolet irradiation curable resin and the By irradiating the surface of the mold with ultraviolet light, the ultraviolet irradiation curable resin is solidified to form the resin lens, and the resin lens is transferred to the mold while the photocatalytic effect of the photocatalytic film on the mold surface is obtained. A method of molding a compound lens, which comprises peeling from a surface.