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AssigneeCanon Kabushiki Kaisha
InventorMasanobu Ohgane
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An optical element having a diffraction shape uses an optical material comprising at least N-vinylcarbazole, polyvinylcarbazole, and the light polymerization initiator. By using such optical material, it is possible to suppress crystallization of the optical material during molding even at room temperature and appropriately control the dropping amount suited for replica molding. It is possible to provide the optical material also suited for replica molding at room temperature by setting a ratio of N-vinylcarbazole to polyvinylcarbazole, i.e. N-vinylcarbazole/polyvinylcarbazole, to a range between 90/10 and 70/30.
An optical material for molding an optical element through light polymerization, comprising:
Dependencies are inferred from the claim text.
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For optical correction, e.g. distorsion, aberration: with diffracting elements
Macromolecular compounds obtained by polymerising monomers on to polymers of nitrogen-containing monomers
Macromolecular compounds obtained by polymerising monomers on to polymers of nitrogen-containing monomers as defined in group C08F26/00: on to…
Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds ;…:…
Term end not estimated
1. Field of the Invention
The present invention relates to an optical material used for optical elements such as a lens, a filter, a mirror, and a refraction optical element, and more particularly to an optical material with large refractive index dispersion. Further, the present invention relates to an optical element formed by the optical material and a method of forming the optical element.
2. Related Background Art
FIGS. 1A, 1B and 1C schematically show a method of molding an optical element according to a first embodiment;
FIGS. 2A, 2B and 2C schematically show an experiment method according to example 1;
FIG. 3 is a graph showing a result of the differential scanning calorimetry for comparison experiment example 5 according to example 2;
Embodiments of the present invention will be described in further detail. The present invention can suppress crystallization during molding at room temperature and appropriately control the dropping amount suited for replica molding by using an optical material comprising N-vinylcarbazole, polyvinylcarbazole, and a light polymerization initiator.
N-vinylcarbazole is a large π-conjugated molecule. Accordingly, N-vinylcarbazole causes electronic coupling between π electrons between molecules and is crystallized at room temperature. This crystallization can be suppressed by adding polyvinylcarbazole to N-vinylcarbazole. The use of polyvinylcarbazole can prevent electronic coupling between π electrons in N-vinylcarbazole.
Other compounds can be also used for simply suppressing crystallization of N-vinylcarbazole. However, N-vinylcarbazole is a material of very high refractive index dispersion. If N-vinylcarbazole is mixed with a compound having a refractive index dispersion lower than that of N-vinylcarbazole, the refractive index dispersion for the entire compound decreases, making it impossible to fully exert the characteristics of N-vinylcarbazole. Polyvinylcarbazole has almost the same refractive index dispersion value as that of N-vinylcarbazole. Accordingly, it is possible to fully exert the characteristics of N-vinylcarbazole without decreasing the refractive index dispersion for the entire compound. Since polyvinylcarbazole is an N-vinylcarbazole polymer, it has no effect on characteristics of a molded optical element.