| 摘要 |
PROBLEM TO BE SOLVED: To provide an image input apparatus capable of carrying out measurement with high accuracy at all times wherein a heat-absorbing filter is hardly destroyed and a damage by heat ray radiation from a light source is not caused and to provide an image evaluation apparatus. SOLUTION: The task above can be solved by using filters with a small area having a small temperature gradient around maximum light emission parts at both ends of a halogen lamp 12 at which a cracked filter tends to cause and using filters with a comparatively large area at the other positions. That is, since the size of filaments 20 is greater around both the ends of the halogen lamp 12 for the luminous intensity distribution and the heating value is high, the heat-absorbing filter 10 is divided into filter pieces 30c with a small area to prevent a damage due to the temperature gradient, and since the size of the filaments 20 is small and the heating value is small around the middle parts of the halogen lamp 12, the filter 10 is divided into filter pieces 30a with a comparatively large size so as to prevent the cost increase. It is furthermore better that the filter pieces 30b of a medium size are arranged in the middle part between the both to balance the cost and the heat resistance performance. COPYRIGHT: (C)2006,JPO&NCIPI
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