PROJECTOR WITH INCLINATION ANGLE MEASURING DEVICE

Japanese Patent JP3709405

B2

PROBLEM TO BE SOLVED: To provide a projector having an inclination angle measuring device which can measure at low cost an inclination angle in a vertical and/or horizontal direction of a projection face to a projected optical axis of the projector, for correcting image distortion.
SOLUTION: A homogeneous high intensity light is projected to the projection face from a projection lens 21 of a projection device 20. Through one pinhole 51 made on the front wall surface of the projector 10 at predetermined intervals from the projected optical axis 27, reflected light is received by three light intensity measuring sensors 52 located in a line at the center and both ends on an internal reference line 29. On the basis of the result of light intensity measuring, a received light intensity analyzing and inclination angle calculating part 53 calculates a quadratic curve connecting the tips of bar graphs of light intensity at each location when the reference line is taken as a horizontal axis and the light intensity, as a vertical axis. An angle made by a straight line connecting a location on the horizontal axis at the vertex of the quadratic curve and the pinhole 51 and a straight line parallel to the projected optical axis passing the pinhole 51 is taken as an inclination angle made by the projection face 70 and a surface vertical to the projected optical axis 27, and image controlling part 23 is controlled so as to eliminate image distortion.

Youichi Tamura
Toru Kataoka

JP2003311345A

October 26, 2005

September 03, 2003

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NEC View Technology Co., Ltd.

G01C9/06; G03B21/00; H04N5/74; (IPC1-7): H04N5/74; G03B21/00

JP2004134908A

Akio Miyazaki
Shinichi Iwata
Masaaki Ogata
Ishibashi Masayuki

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