| 摘要 |
PURPOSE:To enable photosensors of extremely high photo-response speed, high- speed image readers to be obtained without needing convergent optical fiber arrays, by using the photoelectric conversion element with the S-shaped rise characteristic in photocurrent and bias light. CONSTITUTION:Of beams l1 from a light source 2, a beam l3 transmitting through a semitransparent film 8 is kept given directly from the back of a photoconductive element group 5 as a fixed amount of bias light. Of the incident beams l1, a beam passing through an illumination window 9 strikes against the original writing 3, and its reflected beam l2 against the photoconductive element group 5, resulting in the conversion of photo signals into electric signals. In this case, a photoconductive element having Si-shaped rise characteristic in photocurrent is used: the element of large photocurrent which is made of a II-II compound semiconductor easy of electrical signal processing is preferable. Above all, the element made mainly of CdS-CdSe solid solution has particularly large photocurrent in II-VI group semiconductors and allows sensitivities over the whole area of visible light, so is further preferable. |
