| 摘要 |
A Fresnel lens sheet (200) for use in a luminaire comprises a transparent sheet (210) having a first surface (212) on one side which is substantially planar and a second surface (214) on the other side; and a Fresnel lens part (220) containing a plurality of concentric convex prisms (222) formed on the second surface (214), each of the convex prisms (222) having a cross-section of substantially triangular structure, wherein the substantially triangular structure has an apex formed by joining a first curved portion (226) and a second curved portion (224), and a base (228); and this triangular structure has a ratio of a radius of the second curved portion (224) to a base width ("w") ranging from 0.1 to 0.5. The invention also provides a luminaire utilizing the Fresnel lens sheet of the invention. |
