| 摘要 |
PURPOSE:To form a small-sized original illuminating device which can improve considerably the illumination efficiency, by providing a concave mirror which reflects the light emitted from an aperture type fluorescent lamp and condenses it to a position to be illuminated and focusing the light emitted from the center of luminescence of the fluorescent lamp to the position to be illuminated with an approximate unmagnification by the concave mirror. CONSTITUTION:Most of the luminous flux emitted from an aperture 2 of a fluorescent lamp 1 is made incident to a main concave mirror 9 and is condensed to a read position F2 by this mirror 9, and in this case, l1approx.=l2 is true so that the light emitted from a center F1 of luminescence of the fluorescent lamp 1 is focused in unmagnification in the read position F2 without aberrations. An auxiliary concave mirror 10 reflects the light, which comes from the main concave mirror 9 and is reflected in the read position F2, again to return it to the read position F2. Since the light emitted from the center F1 of luminescence is focused in the read position F2 with unmagnification by the main concave mirror 9 and the light emitted from the part other than the center F1 of luminescence is focused near the read position F2 similarly, the condensing efficiency is considerably enhanced. |
