| 摘要 |
PURPOSE:To obtain a stable optical lens even in case of a variation of temperature, by making a transparent body adhere to the end of a focusing rod lens so that the end of the transparent body becomes an image formation surface of the lens. CONSTITUTION:As one example of a transparent body, glass plates 5, 6 and 7 are provided, on the end of the glass plate 6, a filter 4 is vapor-deposited, and these glass plates 5, 6 and 7 are made to adhere to the end of a focusing rod lens 8 being shorter than 1/4 period length. Thicknesses of these glass plates 5, 6 and 7, and the lens 8 are selected so that other ends of the glass plates 5,6 and 7 become a focal surface of the lens 8. According to such a constitution, as for the filter 4, only that which is excellent in its characteristic is selected and used, therefore, a branching filter can be manufactured without wasting the lens 8. Also, as for the filter 4, that which has been vapor-deposited on the large plate 6 is cut and used, therefore, it can be manufactured at a low cost. |
