| 摘要 |
PROBLEM TO BE SOLVED: To provide a collimator lens unit without any deterioration of light use efficiency due to the increase of the ratio of light radiated at a great angle among the light radiated to a region to be radiated.SOLUTION: A collimator lens unit 20 provided with a first lens 22 and a second lens 24 makes light emitted from a solid light source device 10 of a Lambert light emission type approximately parallel. In this case, a preceding stage aspherical surface formed on an incident surface 25 of the second lens 24 includes a flux density distribution conversion function for converting to a prescribed flux density distribution and a subsequent stage aspherical surface formed on an emission surface 26 of the second lens 24 includes a function for making the light from the preceding stage aspherical surface approximately parallel. The flux density in the vicinity of an optical axis in the collimator lens unit 20 in the light emitted from the collimator lens unit 20 is made higher than the flux density in the periphery section which is separated from the optical axis of the collimator lens unit 20. |
