FOCAL POINT DETECTION APPARATUS, FOCUSING SYSTEM, CAMERA, AND FOCAL POINT DETECTION METHOD

WIPO Patent Application WO/2003/029870

A1

First to third liquid crystal filters are arranged at first to third different distances from a predeterminate image formation surface. Light flux passing through the liquid crystal filters is received by a photodiode and converted into an electric signal. A variable−density stripe pattern of a predetermined space frequency is formed on the first liquid crystal filter while the second and the third liquid crystal filter are in the state of entire transparency and a first signal is output from the photodiode. Similarly, a variable−density stripe pattern is formed on the second liquid crystal filter while the first and the third liquid crystal filter are in the state of entire transparency and a second signal is output. Similarly, a variable−density stripe pattern is formed on the third liquid crystal filter while the first and the second liquid crystal filter are in the state of entire transparency and a third signal is output. According to the first, second, and third signals, a focal point position is calculated.

JP6426890	Focus detection device and method, and imaging device
JP2000111787	FOCUSING DEVICE

IWANE TORU (JP)

PCT/JP2002/009968

April 10, 2003

September 26, 2002

Click for automatic bibliography generation  

NIPPON KOGAKU KK (JP)
IWANE TORU (JP)

G02B7/28; G02B7/38; G03B7/099; G03B7/0997; H04N5/232; (IPC1-7): G02B7/36; G03B3/00; H04N5/232

JPH0784177A	1995-03-31
JPH04333010A	1992-11-20
JPS5934504A	1984-02-24

Nagai, Fuyuki (3-2-4 Kasumigaseki Chiyoda-ku, Tokyo, JP)

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