Synthetic resin lens manufacturing method, reformed quality synthetic resin material manufacturing method and optical pickup device

Abstract

The invention provides a synthetic resin lens manufacturing method, a reformed quality synthetic resin material manufacturing method and an optical pickup device. A synthetic resin material, which is small in decreasing degree of the transmissivity of red laser light due to accumulated irradiation of the red laser light but is large in decreasing degree of the transmissivity of blue-violet laser light due to accumulated irradiation of the blue-violet laser light, has been widely used as an objective lens material in compliance with the requirement for the red laser light. The synthetic resin material, however, has not been able to be put into practical use for an objective lens material in compliance with the requirement for the blue-violet laser light. It is an object to make the synthetic resin material usable as such an objective lens material for the blue-violet laser light. An electromagnetic wave with a shorter wavelength than that of a blue-violet laser light is irradiated to a lens member made of a synthetic resin material so that the degree of the transmissivity change of the blue-violet laser light is adjusted in the lens member due to accumulated irradiation of the blue-violet laser light.

Description

technical field [0001] The present invention relates to a synthetic resin lens such as an objective lens used in an optical pickup device for reading signals recorded on an optical disk and recording a signal on the optical disk, and its raw material. Background technique [0002] An optical disc device capable of performing a signal reading operation and a signal recording operation by irradiating a signal recording layer of an optical disc with laser light irradiated from an optical pickup device has been widely spread. [0003] As an optical pick-up device, the method of using an optical disk called CD or DVD is generally promoted, but recently, a method using an optical disk with increased recording density, that is, Blu-ray standard or HD DVD (High Density Digital Versatile Disk) standard has been developed. disc method. [0004] Infrared rays with a wavelength of 780 nm are used as laser light for reading signals recorded on CD-compliant discs, and infrared rays with ...

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Problems solved by technology

[0013] When the transmittance of the objective lens is reduced in this way, the intensity of the laser light condensed on the disk surface of the optical disk becomes smaller, and the reproduction operation of the signal recorded on the optical disk and the recording operation of the signal cannot be performed normally.

In order to solve this problem, as the material of objective lens, use the synthetic resin material that can not be subjected to the influence of blue-violet laser, for example the synthetic resin material that is called Geonex (ゼゼリツツクス) 340R that Japan Geon (Japan ゼオン) company makes, but this synthesis The resin material is more expensive than the material used for the objective lens for DVD, and there is a problem that the price of the optical pickup cannot be reduced.

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