Production method of optical element and optical element

Abstract

A production method of an optical element, which is utilized in a pickup apparatus using a light source emitting light having wavelength of 380 nm to 420 nm and has a functional layer such as an anti-reflection film 60 formed on a molded portion 50 comprising a resin having an alicyclic structure, comprising steps of forming a first SiO layer 62 in the molded portion 50 by a vapor deposition process using SiO as an evaporation source and introducing O2 gas under a predetermined pressure, forming a second SiO layer 64 on the first SiO layer by a vapor deposition process using SiO as an evaporation source and introducing O2 gas under a pressure lower than the pressure used in forming the first SiO layer 62, and oxidizing the first SiO layer 62 and the second SiO layer 64.

Description

technical field [0001] The invention relates to a manufacturing method of an optical element and the optical element. Background technique [0002] In recent years, in optical devices such as optical pickup devices, compared with conventional CDs using a light source with a wavelength of about 780nm and DVDs using a light source with a wavelength of about 650nm, in order to further increase the recording density and increase the recording capacity, a An optical device corresponding to a Blu-ray Disc (hereinafter sometimes referred to as "BD") using laser light with a wavelength of 380 to 420 nm. [0003] On the other hand, optical elements such as objective lenses and collimator lenses used in such optical devices are expected to be manufactured with resins that can be manufactured easily and at low cost compared with glass with high manufacturing costs. High light transmittance, often forming anti-reflection film. [0004] However, when an antireflection film is formed on...

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Problems solved by technology

[0004] However, when an antireflection film is formed on an optical element made of resin, since the film (mainly a metal oxide film) is generally an inorganic substance, compared with the case where glass is used as a base material, there are problems with the use of the base material. The difference in the coefficient of linear expansion of the resin becomes large, and problems such as peeling or cracking (cracks) tend to occur

In particular, SiO, which is generally used as an anti-oxidation film or hard coat 2 When used as the first layer, there is a problem that sufficient adhesion to the resin cannot be obtained

However, considering the necessity of necessary optical characteristics, the materials that are not desirable to be used are limited, and a solution is desired.

In addition, when a laser with a wavelength of 380 to 420 nm is used as a light source, the degradation of the resin substrate itself due to the energy of the laser itself and the further increase in the density of the recording medium inevitably require improvement in optical precision, and changes in optical properties due to moisture absorption of the resin are also inevitable. become a problem

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