Title:
焦点検出装置、合焦システム、カメラおよび焦点検出方法
Document Type and Number:
Japanese Patent JP4379121
Kind Code:
B2
Abstract:
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.
Inventors:
Toru Iwane
Application Number:
JP2003533026A
Publication Date:
December 09, 2009
Filing Date:
September 26, 2002
Export Citation:
Assignee:
NIKON CORPORATION
International Classes:
G02B7/36; G02B7/28; G02B7/38; G03B7/099; G03B7/0997; G03B13/36; H04N5/232; G03B7/28
Domestic Patent References:
| JP7084177A | ||||
| JP4333010A | ||||
| JP59034504A | ||||
| JP51016020A | ||||
| JP63136011A | ||||
| JP57138617A |
Attorney, Agent or Firm:
Fuyuki Nagai
Takao Watanabe
Takao Watanabe