Mold, optical element and method for manufacturing the same

Abstract

A method for manufacturing a mold or an optical element provided with a fine surface roughness according to an embodiment of the present invention is a method in which the fine surface roughness has been manufactured using a reactive etching apparatus. In the apparatus a substrate or a film made of a semiconductor or a metal which reacts with sulfur hexafluoride is placed, and into which a mixed gas of sulfur hexafluoride and oxygen is introduced and tuned into plasma such that oxides are made to be scattered on a surface of the substrate or the film, the surface of the substrate or the film is made to undergo etching by the sulfur hexafluoride while the oxides function as an etching mask, and thus the fine surface roughness is formed on the surface of the substrate or the film.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This is a Continuation-in-Part of International Patent Application No. PCT / JP2013 / 061889 filed Apr. 23, 2013, which designates the U.S. and was published under PCT Article 21(2) in English, which claims priority from U.S. Provisional Patent Application No. 61 / 727,284, dated Nov. 16, 2012. This Continuation-in-Part application also claims priority from U.S. Provisional Patent Application No. 61 / 968,629 filed on Mar. 21, 2014. The contents of these applications are hereby incorporated by reference.BACKGROUND[0002]1. Field[0003]The present invention relates to a method for manufacturing a mold or an optical element provided with a fine surface roughness, the mold and the optical element.[0004]2. Description of the Related Art[0005]Anti-reflective structures having grating shapes, the pitch (or the period) of the grating being smaller than the wavelength of light, are used in optical elements. As a method for manufacturing molds for such anti-...

AI Technical Summary

Benefits of technology

The present invention provides a simplified process for manufacturing molds or optical elements with fine surface roughness without the need for patterning process for an etching mask. The fine surface roughness can be achieved in a wide range including a visible light region and an infrared region. The fine surface roughness can be used to form an anti-reflective structure or a diffusing structure on the mold.

Problems solved by technology

However, the required manufacturing time excessively increases as an area in which pattern is to be formed increases.

Thus, the pitch cannot be made highly fine.

Further, when the method is applied to patterning on curved surfaces, degree of flexibility in design is low.

Accordingly, there has been a problem that anti-reflection property deteriorates in the lower wavelength area of visible light.

Thus, methods in which patterning is used are complicated in process and are time-consuming.

However, the method described in U.S. Pat. No. 8,187,481B1 has a problem when the method is applied to manufacture a high-performance anti-reflective structure.

However, because of the properties of the manufacturing methods, pitch of the surface roughness is restricted to 1 micrometer or less.

Thus, a method for manufacturing a mold or an optical element by which fine surface roughness having pitches of a wide range including infrared region can be formed on a surface having a large area or on a curved surface, has not been developed.

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