| 摘要 |
PROBLEM TO BE SOLVED: To improve use efficiency of light by integrating and forming a narrowing optical system including a reflecting structure to narrow a radiation angle of individual light-emitting elements on a light-emitting element array in the case where a light projected from the light-emitting element array forms an image on a photodetecting face via an image formation optical system. SOLUTION: In the case where a light projected from an LED array head 2 forms an image by an image formation optical system 1 on a photosensitive face 3 as a photodetecting face, the LED array head 2 is formed with using an LED array (light-emitting element array) 5 as a base which includes a plurality of LEDs 4 as light-emitting elements arranged in an array. A reflecting mirror 7 constituting a narrowing optical system 6 is formed separately on the LED array 5 for each LED 4. That is, the narrowing optical system 6 is integrated on the LED array 5. While a part of a radiation light from the LEDs 4 is brought as a direct light L3 into the image formation optical system 1, the other part is reflected at the reflecting mirror 7 and sent as an indirect light L4 into the image formation optical system 1. |
