Fresnel lens and optical device provided with same

• US 10,544,918 B2
• Filed: 10/07/2015
• Issued: 01/28/2020
• Est. Priority Date: 10/23/2014
• Status: Active Grant

• Current Assignee: Daicel Corporation
• Original Assignee: Daicel Corporation
• Inventors: Fujikawa, Takeshi, Fukui, Sadayuki
• Primary Examiner(s): Daneils, Matthew J
• Assistant Examiner(s): Swier, Wayne K.
• Application Number:
  US15/515,523
• Publication Number:
  US 20170227190A1
• Time in Patent Office: 1,574 Days
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 39/026 characterised by the shape of the surface
• CPC Class Codes: B29C 39/24 Feeding the material into the mould
• CPC Class Codes: B29D 11/00269 Fresnel lenses
• CPC Class Codes: B29D 11/0048 Moulds for lenses moulds for plastic articles in general B29C33/00
• CPC Class Codes: B29K 2063/00 Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2509/00 Use of inorganic materials not provided for in groups B29K2503/00 - B29K2507/00, as filler
• CPC Class Codes: B29L 2011/005 Fresnel lenses
• CPC Class Codes: C08G 59/22 Di-epoxy compounds
• CPC Class Codes: C08G 59/226 Mixtures of di-epoxy compounds
• CPC Class Codes: C08G 59/24 carbocyclic
• CPC Class Codes: C08G 59/245 aromatic
• CPC Class Codes: C08L 63/00 Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: F21L 4/00 Electric lighting devices with self-contained electric batteries or cells
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: G02B 1/04 made of organic materials, e.g. plastics G02B1/08 takes precedence
• CPC Class Codes: G02B 1/041 Lenses
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: H04N 23/56 provided with illuminating means

Abstract

Provided is a Fresnel lens which has excellent heat resistance and which can covert light even from a poor-quality semiconductor light sources into uniform, high-quality light and can disperse the resulting light without lowering the central illuminance. The Fresnel lens according to the present invention includes two or more sawtooth prisms in a surface thereof and is made of a cured product of a curable composition containing an epoxy compound (A). Of the sawtooth prisms, a sawtooth prism having a longest inclined side in a cross section has a roughened surface, where the cross section is given by cutting the Fresnel lens in a plane which passes through the center of the Fresnel lens and which is perpendicular to a reference plane of the Fresnel lens.

Claims

1. A Fresnel lens comprising two or more sawtooth prisms in a surface thereof,

wherein the Fresnel lens is made of a cured product of a curable composition containing (A) an epoxy compound,

wherein, of the sawtooth prisms, only a sawtooth prism having a longest inclined side in a cross section has a roughened surface having an arithmetic mean surface roughness (Ra) of 1 to 30 μ

m, where the cross section is given by cutting the Fresnel lens in a plane which passes through a center of the Fresnel lens and which is perpendicular to a reference plane of the Fresnel lens.

2. The Fresnel lens according to claim 1,

wherein the epoxy compound (A) comprises a compound represented by Formula (a):

3. The Fresnel lens according to claim 1, wherein the curable composition further comprises:

(B) an oxetane compound; and

(C) a cationic-polymerization initiator,

in addition to the epoxy compound (A).

4. The Fresnel lens according to claim 1,

wherein the Fresnel lens has a glass transition temperature of 100°

C. or higher.