| 摘要 |
PURPOSE:To form the luminous flux of a semiconductor laser, etc., having different radiation angles to a nearly circular parallel luminous flux so as to miniaturize the cross section of the luminous flux by using a anamorphotic single lens which has different refractive indexes in horizontal and vertical directions and, at the same time, satisfies specific conditions. CONSTITUTION:This anamorphotic single lens 6 is constituted in such a way that the 1st surface on a light source 4 side is formed to a toric surface having a high-order expanded term of the 4th or higher order which contributes to aberration correction to the rays of light of luminous fluxes in a large-radiation angle direction, for example, in the horizontal direction only. The 2nd surface which is the light emitting side is formed to a toric surface having a high-order expanded term of the 4th or higher order which contributes to aberration correction to rays of light of luminous fluxes in a small-radiation angle direction, for example, in the vertical direction only. This anamorphotic single lens is caused to satisfy formulae I and II, where n1, d1, and (f) respectively represent the refractive index, thickness of the lens central part, and focal distance of the lens related to the direction in which the radiation angle of the luminous flux emitted from the light source is large. Therefore, an emitted luminous flux having a nearly circular cross section can be obtained efficiently and, moreover, the device can be miniaturized. |
