To make it possible to improve the accuracy to the production, assembly and measurement of an optical element having plural inside reflection surfaces, to produce the optical element with good accuracy and to form the optical element to a planar form and thin type.
Flanks B and B' parallel to a direction where first reflection surface groups and second reflection surface groups approximately face each other are formed on the optical element which has the first reflection surface groups arrayed with two refraction surfaces R1 and R8 and the plural inside reflection surfaces R2, R4 and R6 in a prescribed direction (a Y-axis direction) and the second reflection surface groups formed to face these first reflection surface groups and inclusive of at least one inside reflection surfaces R3, R5 and R7 and introduces the incident light from the one refraction surface toward the other refraction surface while alternately reflecting the light with the first reflection surface groups and the second reflection surface groups. Further, projecting parts A and A' which have A1 and A1' continuous with these flanks without differences in level and do not execute an optical effect are formed at both ends of the element in the prescribed direction described above.
ARAYA MICHIHARU
HOSHI HIROAKI
AKIYAMA KENJI
TANAKA TSUNEFUMI
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