Title:
ACTIVE RANGE FINDER
Document Type and Number:
Japanese Patent JPH0571957
Kind Code:
A
Abstract:
PURPOSE:To eliminate the possibility of the erroneous measurement of a distance even under illumination performing high frequency flashing. CONSTITUTION:A light projection part has a plurality of the frequencies of projected modulated light (oscillation circuits A18, B19) and a light detection part has band pass characteristics (band-pass filter circuits A16, 8B) capable of being changed over so that the frequency of the light projection part becomes almost center frequency and the light projection part is set to an inoperative state (control circuit 11, 21) to change over the band-pass characteristics of the light detection part (9) and the outputs of the light detection part corresponding to respective frequency bands are compared to calculate the frequency band wherein the output of the light detection part becomes the min. signal (11) and the light projection part is changed over to the frequency to measure a distance (16).
Inventors:
IIDA KIWA
HIGAKI RIICHI
TSURU HIROYUKI
HIGAKI RIICHI
TSURU HIROYUKI
Application Number:
JP25848091A
Publication Date:
March 23, 1993
Filing Date:
September 10, 1991
Export Citation:
Assignee:
NIKON CORP
International Classes:
G01B11/00; G01C3/06; G02B7/32; (IPC1-7): G01B11/00; G01C3/06; G02B7/32
Attorney, Agent or Firm:
Hisao Kamata (1 person outside)
Next Patent: OPTICAL MEASURING DEVICE FOR MINUTE DISPLACEMENT