| 摘要 |
PURPOSE:To reduce the number of particles of alpha rays incident on a chip by a method wherein a sealing glass sheet is formed by highpurity glass and the coefficient of thermal expansion of a package is set at an intermediate value between coefficient of thermal expansion of a CCD imager chip and the coefficient of thermal expansion of the sealing glass sheet. CONSTITUTION:A device a is constituted roughly by a package 1, a CCD imager chip 2 and a sealing glass sheet 3 sealing the package 1. The CCD imager chip 2 is placed on the package 1 composed of a glass ceramic; the sealing glass sheet 3 composed of high-purity quartz glass is bonded to the package 1. The coefficient of thermal expansion of the package 1 is set at an intermediate value between the coefficient of thermal expansion of the CCD imager chip 2 and the coefficient of thermal expansion of the sealing glass sheet 3. Accordingly, a change in expansion between the CCD imager chip 2 and the sealing glass sheet 3 is relaxed by the package 1. By this setup, the number of particles of alpha rays incident on the CCD imager chip 2 is reduced; stability and reliability of an image can be improved.
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