Title:
PROJECTION OPTICAL SYSTEM AND PROJECTION IMAGE DISPLAY DEVICE
Document Type and Number:
Japanese Patent JP2015075627
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a compact, bright, and relatively high-performance projection optical system and a projection image display device incorporating the same.SOLUTION: A projection optical system of the present invention comprises first through sixth lenses arranged in order from the expansion side. The first lens has negative refractive power and is a bi-aspherical lens having greater curvature on the reduction side than on the expansion side. The second lens is a biconvex lens. The third lens and fourth lens are a meniscus lens, having a convex surface on the reduction side, and a lens having an expansion-side surface which is concave and has greater curvature than a reduction side surface, respectively, and are cemented together to form a cemented lens. The fifth lens is a biconvex lens. The sixth lens is a convex lens having a greater sag amount on the expansion side and having an aspherical surface at least on the reduction side.
Inventors:
SHIOKAWA KOJI
Application Number:
JP2013211680A
Publication Date:
April 20, 2015
Filing Date:
October 09, 2013
Export Citation:
Assignee:
SEIKO EPSON CORP
International Classes:
G02B13/00; G02B13/18; G03B21/00; G03B21/14
Attorney, Agent or Firm:
Masahiko Ueyanagi
Kazuaki Watanabe
Kazuaki Watanabe