| 摘要 |
PURPOSE:To restrain radiation dosage to a solid-state image pickup element, by a method wherein the dosage emitted from a transparent plate and a nonreflective film is controlled, and the summed dosage of alpha rays and beta rays after control is made smaller than the summed dosage of alpha rays and beta rays before the control. CONSTITUTION:An outer enclosure vessel 21 has a cavity part 22 provided with an aperture. A solid-state image pickup element 20 is protected by arranging a transparent cap 27 so as to cover the aperture surface 26 of the cavity part 22. The main part of the transparent cap 27 is constituted of a transparent plate 28 constituted of transparent glass, and nonreflective films 29, 30 are arranged on both surface. The summed dosage of alpha rays and beta rays emitted from the transparent plate 28 and the nonreflective films 29, 30 after control is made smaller than the sammed dosage before the control. Thereby the deterioration of characteristics of the solid-state image pickup element 20 which is to be caused by the emitted radiation can be prevented. |
