| 摘要 |
PURPOSE:To provide a device which is not bulky but miniaturized, by a method wherein a shutter unit, which can continuously change an opening degree, is positioned in front of a light source, and by driving it through the working of a reversible motor, the output of a light receiving element is compared with a reference value. CONSTITUTION:A shutter unit 2 is located in front of and in the proximity of a light source lamp 1, and a square columnar casing 3 is secured to the front surface of the unit 2. A diffuser panel 4 is attached to the front end surface of the casing 3, and simultaneously, a mask panel 5, being overlapped with the panel 4, is set to form a luminance surface 6. A reversible motor 8, provided with a reduction gear 7, is mounted to the shutter unit 2, and this enables the continuous changing of the slit width of the shutter positioned right in front of the light source lamp 1. A light receiving element 9 is located facing and opposite to the luminance surface 6, a light receiving element 10 is located facing and opposite to the light source lamp 1, and this causes controlling of them through the working of a control circuit substrate 11. |
