Apparatus for sensing the wavelength and intensity of light

Claim 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.