| 摘要 |
Apexes (310) of lenses (31) are positioned to be shifted from base positions (4) positioned virtually in row and column directions, and the base positions (4) include a plurality of grid points (40) as reference positions for the apexes (310) of the lenses (31), first grid lines (41) linking two of the grid points (40) adjacent in the row direction, and second grid lines (42) linking two of the grid points (40) in the column direction. The directions of the first and the second grid lines (41, 42) match with the radial directions of the beam diameters of light in a first and a second direction, the first grid lines (41) are shorter than the beam diameter in the first direction, and the second grid lines (42) are shorter than the beam diameter in the second direction. As a consequence thereof, the interference fringe and irregularities in light distribution are reduced, and a highly uniform diffusion plate (3) is realized. |
