Title:
PROJECTION OPTICAL SYSTEM
Document Type and Number:
Japanese Patent JP3049676
Kind Code:
B2
Abstract:
PURPOSE: To miniaturize a lens system enlarging and projecting the original picture of a projected image on a screen surface and also to maintain high optical performance.
CONSTITUTION: As to a projection optical system projecting the original pictures of the projected image 6, 7, and 8 on the screen surface S; the projection optical system is provided with a first lens group L1 having negative refracting power, a second lens group L2 having positive refracting power, a third lens group L3 constituted of a plane-convex lens whose one surface is convex on a screen side and the other surface is flat, and an illuminating light introducing means 4 between the second lens group L2 and the third lens group L3 in order from a screen side; the illuminating light introducing means 4 reflects a luminous flux from a light source part 9 arranged outside an optical path toward the third lens group L3 side, the original pictures 6, 7, and 8 are illuminated by the luminous flux passing through the third lens group L3, and the original pictures 6, 7, and 8 are projected on the screen surface S by using the reflected light from the original pictures 6, 7, and 8.
Inventors:
Saburo Sugawara
Application Number:
JP27606392A
Publication Date:
June 05, 2000
Filing Date:
October 14, 1992
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B13/16; G03B21/00; G03B21/14; (IPC1-7): G02B13/16; G03B21/00; G03B21/14
Domestic Patent References:
| JP2250015A | ||||
| JP3122607A | ||||
| JP6250717A | ||||
| JP6381310A | ||||
| JP62180343A |
Attorney, Agent or Firm:
Keizo Nishiyama (2 outside)