| 摘要 |
PURPOSE:To discriminate the wavelength of incident beams from the value of ratios with other outputs while using one of photoelectric conversion outputs as a reference by applying different bias voltage to photoelectric conversion sections for a photosensor in succession. CONSTITUTION:A transparent conductive film 3, a photoelectric conversion section 1 consisting of a P layer 10 by alpha-Si, an I layer 11 and an N layer 12, and an Al electrode 13 are superposed onto glass 2 transparent to incident beams F, thus forming a sensor element. When there is no bias voltage between the electrodes 3 and 13, incident beams F at a short wavelength are all absorbed up to the P layer 10 side in the I layer 11, and generated electrons sufficiently diffuse in a weak built-in electric-field region in the I layer 10, thus efficiently obtaining a photoelectric conversion output. Incident beams are absorbed by the I layer 11 near by the N layer 12 on the projection of long-wavelength beams, electrons do not reach to the electrode because of a weak built-in electric field and recombine, and a sufficient output is not acquired. When bias voltage is altered, incident beams F can be discriminated as a long wavelength when the degree of change of the photoelectric conversion output is large and as a short wavelength when the degree of change is small. |
