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Patent Searching and Data


Title:
LIGHT SPECTRUM MEASURING DEVICE
Document Type and Number:
Japanese Patent JPH09292278
Kind Code:
A
Abstract:

To improve reliability of measuremnt of spectrum by providing a means for impressing reverse bias voltage on a photodetector for avoiding saturation of the photodetector.

Only the specific wavelength component 2A of out-going light from a light source 1 is received with a photodetector 3, and after photoelectrically transferring and amplifying it, it is converted into a digital signal. The maximum output current in the non-saturated state of the photodetector 3 is stored in a control part 6. The output current of the photodetector 3 is obtained from the output value of an A/D converter 5 and the amplification factor of an amplifier 4, and when it is over the maximum output current stored in the control part 6, the control part 6 commands a voltage impressing means 8 to impress reverse bias voltage on the photodetector 3. When the reverse bias voltage is impressed, the light input intensity at which the photodetector 3 begins to be saturated is enlarged. When the output value of the A/D converter 5 is not in the appropriate range, the amplification factor of the amplifier circuit 4 is changed. When the reverse bias voltage control or change of the amplification factor is carried out, the light intensity is measured again by the A/D converter 5.


Inventors:
IWASAKI TAKASHI
Application Number:
JP1996000109604
Publication Date:
November 11, 1997
Filing Date:
April 30, 1996
Export Citation:
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Assignee:
ANDO ELECTRIC
International Classes:
G01J3/02; G01J3/28; (IPC1-7): G01J3/02
Attorney, Agent or Firm:
志賀 正武 (外2名)