Title:
OPTICAL ELEMENT, PROJECTION DEVICE, AND MANUFACTURING METHOD FOR OPTICAL ELEMENT
Document Type and Number:
WIPO Patent Application WO/2014/104106
Kind Code:
A1
Abstract:
[Problem] To provide a diffuser plate which can be processed by wet etching and has high light use efficiency.
[Solution] The abovementioned problem is solved by providing an optical element characterized in that a plurality of recesses are formed in the surface of a substrate, the recesses each have a curved surface part formed by a curved surface, the plurality of recesses are formed such that the bottoms of the recesses are located at two or more different positions in a depth direction, and when the refractive index of the substrate is denoted as n1, the refractive index of a medium around the substrate is denoted as n2, the wavelength of a light flux incident on the substrate is λ, and the range in the depth direction of the bottoms of the plurality of the recesses is ∆d, the following expression is derived.
2/7≤|(n1-n2)×∆d|/λ≤10
Inventors:
MIYASAKA KOJI (JP)
YAMASHITA SHUICHI (JP)
YAMASHITA SHUICHI (JP)
Application Number:
PCT/JP2013/084693
Publication Date:
July 03, 2014
Filing Date:
December 25, 2013
Export Citation:
Assignee:
ASAHI GLASS CO LTD (JP)
International Classes:
G02B5/02; G03B21/00; G03B21/14; H04N5/74
Domestic Patent References:
| WO2006090681A1 | 2006-08-31 |
Foreign References:
| JP2005114772A | 2005-04-28 | |||
| JP2005321610A | 2005-11-17 | |||
| JP2010181862A | 2010-08-19 |
Attorney, Agent or Firm:
ITOH, Tadashige et al. (JP)
Tadashige Ito (JP)
Tadashige Ito (JP)
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