| 摘要 |
PURPOSE:To optionally control the radiated light quantity of a lamp device by changing the ratio between the width of the lens step section and the width of the plane lens section of an inner lens. CONSTITUTION:Plane lens sections 8 with the width w1 are formed between lens steps 7, 7... of an inner lens 6 respectively, and shading stripes 9, 9... are formed at the same pitch as lens steps 7 on the front face at positions corresponding to plane lens sections 8 so that their width W1 is made wider than the width w1 of plane lens sections 8. The incident light flux L1 to lens steps 7 is refracted toward a focal point (f) via shading stripes 9, 9... and passes an outer lens 5 located at the front to become the forward radiation light. The incident light flux L2 to plane lens sections 8, 8... proceeds straight and is cut off by shading stripes 9, 9.... The passing light flux and the cut light flux are determined by the ratio between the width w2 of lens steps 7 and the width w1 of plane lens sections 8. |
