| 摘要 |
The present invention provides a Fresnel lens sheet that scarcely makes the projected image distorted, and others. The Fresnel lens sheet has a plurality of unit total reflection Fresnel lenses arranged on the light-entering side, each unit lens having a light-entering surface and a total reflection surface that totally reflects a part of or all of the imaging light that has passed through the light-entering surface to deflect the light in the desired direction. This Fresnel lens sheet is formed so that it fulfills the relationship H<SUB>1</SUB>xH<SUB>1</SUB>/(10xE<SUB>1</SUB>xT<SUB>1</SUB>xT<SUB>1</SUB>)<=3L/2000, WHERE H<SUB>1 </SUB>represents the length (cm) in the vertical direction of the Fresnel lens sheet; L<SUB>1</SUB>, the length (cm) in the horizontal direction of the Fresnel lens sheet; T<SUB>1</SUB>, the thickness (cm) of the Fresnel lens sheet; and E<SUB>1</SUB>, the modulus of elasticity (kgf/cm<SUP>2</SUP>) of the Fresnel lens sheet. Further, by using, to make up the Fresnel lens sheet, a Fresnel-lens-molded sheet having unit total reflection Fresnel lenses and a backing sheet laminated to the light-emerging surface of the Fresnel-lens-molded sheet, improvement in the efficiency of mold releasing operation that is conducted in the production of the Fresnel lens sheet is achieved.
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