| 摘要 |
A diffractive optical element includes first and second diffractive optical parts to generate diffracted lights two-dimensionally with respect to incident light. The diffracted lights generated by inputting the incident light to the first diffractive optical part are input to the second diffractive optical part in order to generate the diffracted lights from the second diffractive optical part, wherein &thetas;1≧&thetas;2 and k1≧k2 stand or, &thetas;1≦̸&thetas;2 and k1≦̸k2 stand among &thetas;1 and &thetas;2 denote diffraction angles of the first and second diffractive optical parts, and k1 and k2 denote numbers of light spots of the diffracted lights generated by the first and second diffractive optical parts. |
