JPS60243601A - Aspherical lens and its preparation - Google Patents

Abstract

PURPOSE:To obtain an aspherical lens having no optical defect and having high precision by forming a thin film correcting layer for asphericity on a spherical lens using a material having low contraction degree by polymn. consisting of a specified heterocyclic monomer, cationic polymn. catalyst, and a curing agent, etc. CONSTITUTION:The material consisting of the mixture of a heterocyclic monomer such as spiro orthoesters, spiro orthocarbonates, or bicyclo orthoesters, a cationic polymn. catalyst such as Lewis acid, and a curing agent such as org. acid anhydride or polycarboxylic acid resin, having <=1% volume contraction in the polymerized state is filled in a cavity 4 formed by a spherical glass lens 1 and a casting mold 2 having an aspherical surface 7 prepd. by baking a silicone releasing agent. An aspherical lens is obtd. by heating and polymerizing the filled material. Since the lens obtd. by this method causes no contraction during forming, no compression is necessary for the correction of the thickness. Moreover, generation of forming strain is scarcely caused. Therefore, the aspherical lens having high precision is obtd. without generating optical defect even if the polymn. is executed in a short time.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an aspherical lens and a method for manufacturing the same.
In particular, the present invention relates to a high-precision hybrid lens with excellent productivity in which a glass spherical lens is made into an aspherical surface using a thin resin layer, and a method for manufacturing the same.

[Background of the invention]

Lenses for optical purposes are usually made of glass and have a spherical surface. Glass lenses can be easily made into high-precision spherical lenses using a spherical polishing machine, but in order to construct a lens system using only spherical surfaces,
A large number of lenses must be used to correct spherical aberration. In order to create an aspherical surface with glass, each surface must be polished, resulting in poor productivity and high cost. On the other hand, for plastic lenses, productivity can be increased by replicating the mold, so if you make one aspherical mold, you can easily create an aspherical surface.
There were several drawbacks during polymerization.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aspherical lens and a method for manufacturing the same, which can manufacture an aspherical lens with high productivity while eliminating the drawbacks of the prior art described above.

[Summary of the invention]

In order to achieve this objective, the present invention has been developed to reduce polymerization shrinkage, which has been revealed in recent years, whereas conventionally used polymethyl methacrylate and diglycol diallyl carbonate (OR-39) exhibit polymerization shrinkage of 10% or more. The feature is that a polymeric shrinkage material is used and a thin aspherical correction layer is provided on a glass spherical lens to form an aspherical lens.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Heterocyclic monomers, such as spiro-ordiesters, spiro-orthocarbonates, and bicyclo-orthoesters, are mixed with a cationic polymerization catalyst such as a Lewis acid, an organic acid anhydride, or a polycarboxylic acid resin, and polymerized by heating. In extreme cases, it is known that there is almost no volumetric shrinkage, that is, polymerization shrinkage, and in extreme cases, there is slight expansion (for example, Makromo L-Ohtm, 17732
31 (1976)).

As a specific example, the structural formula is shown in FIG.

After heating and fluidizing 69 parts of bifunctional spiro-orthoester to 8060, 31 parts of methylhexahydrophthalic anhydride was added, and after stirring and mixing, 8000, IO
The mixture was degassed under vacuum for 15 minutes at Torr, poured into the mold shown in FIG. 2, and polymerized at 120°0 for 2 hours and then at 180°0 for 2 hours. In Figure 2, 1 is a glass spherical lens, 2
A mold having an aspherical surface and a gasket 3 form a cavity 4 into which the material is injected through an injection port 5. In order to prevent air bubbles from being trapped during injection, it is necessary to take measures such as injecting from the lower injection port 6 and draining upward. The mold 2 used was one in which glass or metal was processed into an aspherical mirror surface by a known method, and the cavity surface 7 was surface-treated with a baking-type silicone mold release agent. Specifically, FSXIff2868 manufactured by Dowhuning Co., Ltd. was applied uniformly to the surface of a stainless steel-based Assub Starbucks steel mold and baked at 150°0 for 6 hours. If the mold release agent treatment is not performed, the injection material will adhere to the mold, making it impossible to release it from the mold.

The spherical glass lens used is a crown type lens such as BK7, F
Although a flint type material such as No. 3 is exemplified, it is not particularly limited, and the shape is not limited to unevenness.

As another example, 63 parts of a powder obtained by pulverizing a polyfunctional spiro-orthoester whose structural formula is shown in FIG. After applying pressure for 5 minutes, 170°0 under no pressure.
A similar lens was obtained even after heating for 8 hours.

〔Effect of the invention〕

As explained above, according to the present invention, there is no need to apply pressure to correct the thickness as seen during molding, so there is no need to pay particular attention to the gasket, and molding distortion is less likely to occur. Therefore, high precision aspherical lenses can be formed without optical defects even if polymerized in a short time.
It is possible to provide an excellent aspherical lens that eliminates the drawbacks of the prior art described above, and a method for manufacturing the same.

[Brief explanation of the drawing]

Ru. 1...Glass spherical lens, 2... A mold having an aspherical surface 7, 3... Gasket, 4...Cavity,

Claims (2)

[Claims] (1) Polymerization using a mixture of heterocyclic monomers such as spiro-ordiesters, spiro-orthocarbonates, and bicycloorthoesters, a cationic polymerization catalyst such as a Lewis acid, and a curing agent such as an organic acid anhydride or a polycarboxylic acid resin. A material with a volumetric shrinkage of 1% or less is placed on a spherical glass lens.
An aspherical lens provided as a thin aspherical correction layer. (2) A mixture of heterocyclic monomers such as 2-pyroordiesters, spiroorthocarbonates, and bicycloorthoesters, a cationic polymerization catalyst such as a Lewis acid, and a curing agent such as an organic acid anhydride or a polycarboxylic acid resin. A method for manufacturing a king made of a material with a volume shrinkage of 1% or less during polymerization using an aspherical mold that is baked with a spherical glass lens and a silicone mold release agent.