Patent ID: 6130782
Filing Date: 2000-10-10
Classification: G02B

Abstract:
A beam splitting element, which comprising:a transparent substrate; anda diffractive grating formed on said substrate for dividing an incident beam into a plurality of diffracted beams, said diffractive grating having a corrugated surface having a plurality of phase patterns arranged in parallel at a predetermined fixed pitch, wherein each of said plurality of phase patterns is formed such that a phase difference .delta. (unit: radian) at a coordinate (Coord.) falls within an allowable range around a center value indicated in a table below when a width of said phase pattern is divided into 64 coordinates: Coord. .delta. Coord. .delta. Coord. .delta.  0 0.00000 22 5.38745 43 5.88525 1 0.00584 23 5.39829 44 5.41667 2 0.15164 24 5.23065 45 4.88464 3 0.35629 25 4.85749 46 4.48907 4 0.58665 26 4.39754 47 4.28159 5 0.83274 27 4.06325 48 4.20466 6 1.09396 28 3.93283 49 4.18625 7 1.37055 29 3.96292 50 4.17531 8 1.65867 30 4.08551 51 4.13989 9 1.95725 31 4.25798 52 4.05584 10 2.26136 32 4.46010 53 3.91493 11 2.56901 33 4.67944 54 3.73275 12 2.87576 34 4.91025 55 3.54727 13 3.17996 35 5.14559 56 3.39464 14 3.48272 36 5.37916 57 3.28598 15 3.77944 37 5.60412 58 3.19644 16 4.06951 38 5.81229 59 3.04634 17 4.34806 39 5.99531 60 2.70057 18 4.61248 40 6.13707 61 1.99407 19 4.85863 41 6.20469 62 1.00901 20 5.08064 42 6.14380 63 0.28129 21 5.26485, and  wherein said diffractive grating divides said incident beam into eight beams.