Title:
ZOOM LENS AND LIQUID CRYSTAL PROJECTOR USING IT
Document Type and Number:
Japanese Patent JPH04172416
Kind Code:
A
Abstract:
PURPOSE:To get a high grade picture quality projector by constituting the projector so that specified conditions are satisfied by a lens system made up of a first group, a second group, a third group and a fourth group in order from the screen side. CONSTITUTION:A lens system is constituted of a variable power system made up of a first group I which has positive refracting power and a second group II which has negative refracting power and moves on an optical axis to change power, and a third group III which has positive refracting power and moves on an optical axis such that the position of an image surface which changes due to movement of the second group II is corrected and a fourth group IV which is thereafter arranged and has positive refracting power in order from a screen side. Of them, the 4th group is made up of a positive lens, a negative lens whose powerful concave faces the screen side, a positive meniscus lens whose concave faces the screen side and a positive lens, and satisfies the conditions of Formulas I - IV so that a good zoom lens is obtained whose back focus and eye relief are long, where the aberration is corrected, whose picture quality is of high grade and suitable for liquid crystal projection.
Inventors:
KIMURA YUICHI
KIMURA SHUNSUKE
KIMURA SHUNSUKE
Application Number:
JP30202290A
Publication Date:
June 19, 1992
Filing Date:
November 06, 1990
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G02B15/167; G03B21/00; G09F9/00; (IPC1-7): G02B15/167; G03B21/00; G09F9/00
Attorney, Agent or Firm:
Akira Kobiji (2 outside)