Diffraction grating

• US 5,629,804 A
• Filed: 01/18/1994
• Issued: 05/13/1997
• Est. Priority Date: 01/18/1993
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Tomono, Haruo
• Primary Examiner(s): Berman, Susan W.
• Application Number:
  US08/182,562
• Time in Patent Office: 1,211 Days
• Field of Search: 522/96, 522/97, 359/576
• US Class Current: 359/576
• CPC Class Codes: C08F 290/147 Polyurethanes; Polyureas
• CPC Class Codes: C08G 18/42 Polycondensates having carboxylic or carbonic ester groups in the main chain
• CPC Class Codes: C08G 18/672 Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams

Abstract

A diffraction grating is constituted by a substrate and a resin layer having a repetitive pattern formed on the substrate. The resin layer is characterized by showing a Young'"'"'s modulus at 100° C. which is at least 2% of that at 20° C. The resin layer may be obtained by curing a photocurable resin composition, including: (A) a polyfunctional urethane-modified polyester (meth)acrylate comprising a polyester oligomer and a plurality of (meth)cryloyl groups bonded to the polyester oligomer via a urethane group, and having a number-average molecular weight of at least 700, (B) a polyfunctional (meth)acrylate having a number-average molecular weight of less than 700, (C) a monofunctional (meth)acrylate, and (D) a photopolymerization initiator.

Claims

1. A diffraction grating comprising:

a substrate and a resin layer having a repetitive pattern formed on the substrate, wherein said resin layer comprises a cured product of a photocurable resin composition comprising;

(i) 25-45 wt. % of (A) a polyfunctional urethane-modified polyester (meth)acrylate comprising a polyester oligomer and a plurality of (meth)acryloyl groups bonded to the polyester oligomer via a urethane group and having a number-average molecular weight of at least 800,

(ii) 31-70 wt. % of (B) a polyfunctional (meth)acrylate having a number-average molecular weight of less than 650,

(iii) 5-44 wt. % of (C) a monofunctional (meth) acrylate, and

(iv) (D) a photopolymerization initiator.

2. A diffraction grating according to claim 1, further comprising a reflection layer on the resin layer.

3. A diffraction grating according to claim 1, further comprising an anti-reflection layer on the resin layer.

4. A diffraction grating according to claim 1, wherein the resin layer shows a Young'"'"'s modulus at 100°

C. which is 10-90% of that at 20°

C.