| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a diffraction optical element which allows acquisition of a diffraction pattern having a uniform light quantity distribution. <P>SOLUTION: The diffraction optical element has a plurality of fundamental units arrayed two dimensionally to generate two-dimensional diffracted light from incident light and projects the diffracted light onto a plane to generate a plurality of light spots within a prescribed range on the plane. When, in the case of the prescribed range being a quadrangle, the number of light spots in a center region of the prescribed range out of N<SB POS="POST">x</SB>×N<SB POS="POST">y</SB>or more regions of the same shape, which the prescribed range is equally divided into, is denoted as M<SB POS="POST">c</SB>and an average of the numbers of light spots in regions at four corners of the prescribed range is denoted as M<SB POS="POST">o</SB>and a maximum diffraction angle of irradiation to the prescribed range is denoted as θd, each of N<SB POS="POST">x</SB>and N<SB POS="POST">y</SB>is an odd number equal to or larger than 3 and 15°≤θd and M<SB POS="POST">o</SB>/M<SB POS="POST">c</SB>>-0.02173×θd+1.314 are true. <P>COPYRIGHT: (C)2013,JPO&INPIT |
