| 摘要 |
PURPOSE:To obtain desired light distribution pattern, high central luminance, and a wide peripheral diffusion angle without relying on light modulation by a front lens by specifying the shapes of a horizontal plane and a vertical plane composing a reflecting plane of a reflector and each spreading angle of reflected light of each reflecting zone. CONSTITUTION:In a reflector 11, a horizontal axis, a vertical axis, and the horizontal axis crossing rectangularily to them are defined as Z, Y, and X respectively and the vertical cross section forms a parabola having the Z axis as a symmetrical axis (F stands for its focus) or a similar curve. A reflecting plane is divided into a plurality of reflecting zones 11A-11D from inside to outside by planes parallel to the Y-Z plane and a spreading angle against the Z axis of light radiated from a light source 12a and reflected by the reflector 11 is defined to be theta and in a reflecting zone 11A, the spreading angle theta decreases gradually from +theta1 to -theta2 from inside to outside and in a reflecting zone 11B, it increases gradually from -theta2 to +theta3 from inside to outside, and in a reflecting zone 11C, it decreases gradually from +theta3 to -theta4 and in a reflecting zone 11D, the reflecting angle theta repeats the increase and decrease in the same way. The absolute value of the increase and decrease of the diffusion angle becomes smaller as it goes outside farther and the diffusion angel in the most outside is defined to be almost zero. |
