| 摘要 |
PURPOSE:To enlarge a vertical diffusion angle effectively by providing specified lens steps belonging to an upper lens step group and a lower lens step group respectively with downward and upward refraction action mainly. CONSTITUTION:A lens 12 has a number of lens steps 13, 14, 15 in its inner surface, that is in an opposed surface to a light source part. A step 13cc at a center of an upper lens step group is an LED diffusion step for controlling light at a center part in direct light from an LED 11 mainly, and it achieves a function of causing relatively downward refraction of the light at the center part of the LED 11. A step 14cc at a center of a lower lens step group is an LED diffusion step for controlling light at a center part in direct light from an LED 11' mainly, and it achieves a function of causing relatively upward refraction of the light at the center part of the LED 11'. Steps 14ul, 14ur, 14dl, 14dr, 14cl, 14cr, 14dc around the step 14cc are LED correcting steps for controlling light at peripheral parts in direct light from the LED 11' mainly, and they achieve functions of causing relatively upward refraction of the light at the center part of the LED 11'. |
