Title:
LIGHT RECEIVER
Document Type and Number:
Japanese Patent JPH02300641
Kind Code:
A
Abstract:
PURPOSE:To reduce the cost of an amplification means and to suppress an influence by level variation and noises to be low by setting a distance between light receiving parts long as to a light receiver for optically detecting the position of an image projected to a screen by a projector. CONSTITUTION:The light receiver 1 is provided with the circular light receiving part 2, the doughnut-shaped light receiving part 3, a dead zone 4 which is interposed between the light receiving parts 2 and 3 and has a certain width, a casing 5, a window glass 6 and a lead wire 7. The distance L from a light source to the light receiving parts 2 and 3 is the sum of a distance provided in order not to be damaged by the contact of the screen 8 being the light source with the front part of the casing 5 of the light receiver 1, the thickness of the casing 5 and the window glass 6 and a necessary distance from the window glass 6 to the light receiving parts 2 and 3. The light receiver is constituted to satisfy D>2XLXtantheta, supposing that the distance between the light receiving parts which are adjacent to each other out of plural light receiving parts is taken as D, the distance from the light source to the light receiving part is taken as L and an angle where diffused light from the light source effectively influences is taken as theta.
Inventors:
IIDA TSUGIO
ASAKURA TAKESHI
NODA AKIRA
ASAKURA TAKESHI
NODA AKIRA
Application Number:
JP12168889A
Publication Date:
December 12, 1990
Filing Date:
May 16, 1989
Export Citation:
Assignee:
MITUTOYO CORP
International Classes:
G01J1/44; (IPC1-7): G01J1/44
Attorney, Agent or Firm:
Yuji Iwahashi