| 主权项 |
1. An optical element comprising:
a first optical layer having a concave-convex surface;
a wavelength-selective reflection layer formed on the concave-convex surface; anda second optical layer formed on the wavelength-selective reflection layer,wherein the wavelength-selective reflection layer has a five-layer structure in which a high-refractive-index layer and a metal layer are alternately stacked, and in the ease when the entire wavelength-selective reflection layer has a geometric film thickness L of 80 nm, a ratio α (=db/da) of an optical film thickness db of the entire metal layer relative to an optical film thickness da of the entire high-refractive-index layer and a ratio β (=d3/d1) of an optical film thickness d3 of the third high-refractive-index layer relative to an optical film thickness d1 of the first high-refractive-index layer, when viewed from either the first optical layer side or the second optical layer side, are included in a first region surrounded by the following formulas (1) to (4), while in the case when the entire wavelength-selective reflection layer has a geometric film thickness L of 90 nm, the ratio α and the ratio β are included in a second region surrounded by the following formulas (5) to (8), and wherein in the case when the entire wavelength-selective reflection layer has a geometric film thickness L of 80 nm<L<90 nm, supposing that each of minute sides formed by dividing a periphery C1 of the first region into n-equal portions, with an intersection between the formula (1) and formula (3) being set as a starting point, is represented as ΔC1i (where i represents a natural number from 0 to n), and that each of minute sides formed by dividing a periphery C2 of the second region into n-equal portions, with an intersection between the formula (5) and formula (7) being set as a starting point, is represented as ΔC2i, and that each of minute regions having a rectangular shape, with ΔC1i and ΔC2i being formed as the two short sides, is defined as ΔSi, the ratio α and the ratio β are surrounded by a circumferential surface S composed of a group of minute regions ΔSi.
α=−0.0004β2+0.0053β+0.0065 (1)α=−1×10−5β2+0.0007β+0.0066 (2)α=−1×10−5β2+0.0005β+0.0119 (3)α=0.012114 (4)α=−0.0002β2+0.0039β+0.0087 (5)α=−3×10−5β2+0.0014β+0.0038 (6)α=−2×10−5β2+0.0006β+0.0112 (7)α=0.010589 (8) |
