Diffractive optical element and optical system having the same

(22) Filed: Apr. 2, 2003 (65) Prior Publication Data US 2003/0189755 A1 Oct. 9, 2003 (30) Foreign Application Priority Data Apr. 4, 2002 (JP) ..................................... .. 2002-102760 Apr. 4, 2002 (JP) ..................................... .. 2002-102762 (51) Int. Cl.7 ................................................ .. G02B 5/18 (52) U.S. Cl. ...................................... .. 359/569; 359/576 (58) Field of Search ............................... .. 359/566, 569, 359/571, 575, 576 (56) References Cited U.S. PATENT DOCUMENTS 4,585,307 A * 4/1986 Dammann et al. ........ .. 359/571 5,044,706 A 9/1991 Chen 5,790,321 A 8/1998 GOIO 5,847,877 A 12/1998 Imamura et al. 6,008,942 A 12/1999 Ogusu et al. 6,064,452 A 5/2000 Ogino 6,157,488 A 12/2000 151111 6,473,232 B2 10/2002 Ogawa

EP 1 186 914 A2 2/2002 EP 1 186 914 A2 3/2002 EP 1 193 512 A2 4/2002 JP 0 441 206 B1 8/1991 JP 6 324 262 11/1994 JP 9 127 322 5/1997 JP 1 013 3149 5/1998 JP 2001-305323 10/2001 JP 2002-071925 3/2002

OTHER PUBLICATIONS

European Search Report.

A. P. Wood “Using Hybrid Refractive—Diffractive Elements In Infrared Petzval Objectives” (1990) Int’l. Lens Desing Conf., vol. 1354, pp. 316-323.

A. D. Kathman and S. K. Pitalo “Binary Optics In Lens Design” (1990), Int’l. Lens Design Conf. vol. 1354, p. 297—309.

* cited by examiner

Primary Examiner—Mark A. Robinson Assistant Examiner—Alessandro Amari (74) Attorney, Agent, 0r Firm—Morgan & Finnegan, L.L.P.

(57) ABSTRACT

A diffractive optical element in which eclipse of rays at a grating side surface of a diffraction grating can be reduced is disclosed. In a diffractive optical element comprises a plurality of diffraction gratings made of different materials are laminated, at least one of the plurality of diffraction gratings includes a region in which the grating side surface inclines or a region in which edges thereof are shifted with respect to the edge of another diffraction grating adjacent thereto. The inclination or shift amount is different according to the positions thereof in a surface of the diffractive optical element in accordance with the incident angle or emergent angle of a specified ray such as a ray determined on the basis of an average value, gravity value, maximum value and minimum value obtained from the distribution of incident angle or emergent angle or the like, rays, etc.

20 Claims, 31 Drawing Sheets

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