PURPOSE: To inhibit the lowering of the sensitivity of each photodiode on a change into a color and the deterioration of the characteristics of spectral responsivity by making the thickness of central layers having three-layer structure, in which conduction types are altered alternately in the direction of substrate depth, different.
CONSTITUTION: Thickness is adjusted so that the allocated spectral characteristics of several photodiode are obtained in a P type region 2. Beams projected through N type regions 4, 14, 24 generate charges, but charges moving in the direction of the surface in charges generated in P type regions 2, 12, 22 function as signal charges. In the constitution, however, charges in the greater part optically pumped diffuse in the direction of the surface and serve as signal charges because the region 22 in which the photodiode 24 for red beams is formed is shaped thickly. The width of the region 12 is made slightly smaller than the region 22 in the photodiode 14 for green. Consequently, beams in an intermediate wavelength region are detected sufficiently, but long-wavelength beam components are removed to a substrate 1. The region 2 for short wavelengths takes a shape that charges excited by long-wavelength beams longer than intermediate wavelengths are absorbed to the substrate 1.
MATSUMOTO SHIGENORI
KURIYAMA TOSHIHIRO
MIZUNO HIROYUKI
| JPS54158121A | 1979-12-13 |