Apparatus for sensing the wavelength and intensity of light

• US 4,309,604 A
• Filed: 07/24/1979
• Issued: 01/05/1982
• Est. Priority Date: 07/24/1978
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yoshikawa, Toshihumi, Tani, Zempei, Aso, Akira, Kawanabe, Hitoshi
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Westin, Edward P.
• Application Number:
  US06/060,189
• Time in Patent Office: 896 Days
• Field of Search: 250/226, 250/211 J, 250/214 P, 357/30, 356/222, 356/223, 356/226, 356/230, 356/402, 356/419, 356/425, 356/435
• US Class Current: 250/226
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01J 2003/466 Coded colour; Recognition of predetermined colour; Determining proximity to predetermined colour
• CPC Class Codes: G01J 3/427 Dual wavelengths spectrometry
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 9/00 Measuring optical phase difference devices or arrangements for controlling the phase of light beams G02F1/01; Determining degree of coherence; Measuring optical wavelength spectrometry G01J3/00
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: H01L 25/043 Stacked arrangements of devices
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 31/02019 for devices characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/11 characterised by two potential barriers, e.g. bipolar phototransistors

Abstract

Disclosed is a solid state wavelength detection system responding to output signals derived from a photoelectric semiconductor device. The photoelectric semiconductor device comprise at least two PN junctions formed at different depth from the surface of the semiconductor substrate. A deeper PN junction develops an output signal related to longer wavelength component of the light impinging thereon. A shallower PN junction develops an output signal related to shorter wavelength component of the impinging light. These two output signals are logarithmically compressed and compared with each other. Difference of the logarithmically compressed output signals represents the wavelength information of the impinging light.

Claims

1. An optoelectric detection system comprising:

a photoelectric semiconductor device including;

a semiconductor substrate;

at least two PN junctions formed in said semiconductor substrate at different depths from the surface of said semiconductor substrate;

first output electrode means for developing first output signals derived from the deeper of said at least two PN junctions; and

second output electrode means for developing second output signals derived from the shallower of said at least two PN junctions;

a first logarithmic compression circuit for logarithmically compressing said first output signals;

a second logarithmic compression circuit for logarithmically compressing said second output signals;

a subtractor connected to receive output signals derived from said first logarithmic compression circuit and said second logarithmic compression circuit, respectively, and

an adder connected to receive outputs from said first and second logarithmic compression circuits;

said subtractor developing a third output signal related to the wavelength of light impinging on said photoelectric semiconductor device;

said adder developing a fourth output signal related to the intensity of light impinging on said photoelectric semiconductor device;

said first PN junction being sensitive to light of a first particular wavelength band;

said second PN junction being sensitive to light of a second predetermined wavelength band including wavelengths greater than those in said first particular wavelength band;

said first PN junction and said second PN junction have substantially equivalent sensitivities to light intensity.