Patent ID: 6064525
Filing Date: 2000-05-16
Classification: B60Q,B60R,G02B

Abstract:
An optical device, comprising:a dichromatic mirror comprised of:a vitreous substrate having a front surface and a rear surface; anda coating provided on the vitreous substrate comprised of a three-layer stack including a semiconductor layer composed of a semiconductor material having a refractive index of more than 3.0, a layer composed of a material having an intermediate refractive index in the range 1.9 to 2.8, and a layer composed of a material having a low refractive index in the range 1.2 to 2.0,wherein the refractive indices of the materials of intermediate and low refractive index differ by at least 0.2, andwherein the dichromatic mirror has a luminous transmittance of at least 20% and a luminous reflectivity of at least 40%; andradiation detecting means positioned on the side of the rear surface of the vitreous substrate.