| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection screen where both primary moire and secondary moire are inconspicuous even when the pitch of a lenticular lens is made small. SOLUTION: A plurality of grooves are formed concentrically on the Fresnel lens surface 2 of a transparent base plate 1, and a plurality of fine cylindrical lens surfaces are arranged in parallel on the lenticular lens surface 3 thereof. Assuming that the pitch of the concentric circle state grooves on the surface 2 is p<SB>F</SB>and the repetitive pitch of the cylindrical lens surface of the surface 3 is p<SB>L</SB>, P<SB>E</SB>=1.0/(1.0/p<SB>F</SB>-[p<SB>L</SB>/p<SB>F</SB>]/p<SB>L</SB>), P<SB>H</SB>=1.0/(1.0/p<SB>L</SB>-1.0/p<SB>F</SB>+[p<SB>L</SB>/p<SB>F</SB>]/p<SB>L</SB>) holds in the case of p<SB>L</SB>>p<SB>F</SB>. P<SB>H</SB>=1.0/(1.0/p<SB>L</SB>-[p<SB>F</SB>/p<SB>L</SB>]/p<SB>F</SB>), P<SB>E</SB>=1.0/(1.0/p<SB>F</SB>-1.0/p<SB>L</SB>+[p<SB>F</SB>/p<SB>L</SB>]/p<SB>F</SB>) holds in the case of p<SB>F</SB>>p<SB>L</SB>. Assuming that ([X]:the integer part of X), P<SB>E</SB>/P<SB>H</SB>≥2.4 or P<SB>H</SB>/P<SB>E</SB>≥2.4 is satisfied. COPYRIGHT: (C)2005,JPO&NCIPI
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