US 7,573,654 B2
Dual focal length lens system
Joseph R. Bietry, Rochester, N.Y. (US); John N. Border, Walworth, N.Y. (US); Scott C. Cahall, Fairport, N.Y. (US); and John D. Griffith, Rochester, N.Y. (US)
Assigned to Eastman Kodak Company, Rochester, N.Y. (US)
Filed on Nov. 27, 2007, as Appl. No. 11/945,445.
Prior Publication US 2009/0135494 A1, May 28, 2009
Int. Cl. G02B 17/00 (2006.01)
U.S. Cl. 359—726  [359/736] 20 Claims
OG exemplary drawing
 
1. A dual focal length optical system comprising:
a first optical system positioned along an optical path, the first optical system including an optical structure having an object side surface and an image side surface, the first optical system also including a first reflective surface of an intermediate reflective element located between the object side surface and the image side surface of the optical structure as viewed along the optical path, the first optical system having a first focal length; and
a second optical system sharing a portion of the same optical path and including a second reflective surface of the same intermediate reflective element as that of the first optical system, the second optical system having a second focal length, the first focal length of the first optical system being longer than the second focal length of the second optical system.