| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device that obtains both of a light utilization efficiency and image-formation performance in each of first and second cross sections.SOLUTION: The optical device comprises: a light source 101 that has a plurality of light emitting points arrayed in a first direction (a Y-direction); and an image-formation optical system 105 that has a plurality of lens optical systems 105a arrayed in the first direction, and forms an image of the plurality of light emitting points on a light reception surface 106 by the image-formation optical system 105. Let, in a first cross section (an XY cross section), &thetas;be a half value of a maximum value of an open angle of an image-formation light flux incident to the light reception surface 106, Pbe resolution and Dbe respective sizes of the image of the plurality of light emitting points to be formed on the light reception surface, and, in a second cross section (a ZX cross section), &thetas;be a half value of a maximum value of an open angle of an image-formation light flux incident to the light reception surface, Pbe resolution and Dbe respective sizes of the image of the plurality of light emitting points to be formed on the light reception surface, the image-formation optical system satisfies a condition of 0.8≤(P(1-PD)tan&thetas;)/(P(1-PD)tan&thetas;)≤1.2. |
