Patent ID: 6392805
Filing Date: 2002-05-21
Classification: G02B

Abstract:
A diffractive optical element comprising a plurality of layers of optical materials and having a relief pattern constituting a diffraction grating formed at one or more cementing interfaces, each cementing interface being between a respective pair of layers of said plurality of layers, the optical materials of a respective pair of layers differing from each other,wherein an optical material abutting a first side of the relief pattern is glass that fulfills Conditions (A1), (B1), and (C1) below, and an optical material abutting a second side of the relief pattern, the second side being opposite the first side, is resin that fulfills Conditions (A2) and (B2) below: nd&lE;1.62â€ƒâ€ƒ(A1) nd&lE;1.6â€ƒâ€ƒ(A2) 55&lE;&ngr;dâ€ƒâ€ƒ(B1) 30&lE;&ngr;d&lE;60â€ƒâ€ƒ(B2) Tg<600â€ƒâ€ƒ(C1) â€ƒwhere &ngr;d represents an Abbe number (which equals (ndâˆ’1)/(nFâˆ’nC)); nd represents a refractive index of the respective optical material, for a d line; nF represents a refractive index of the respective optical material, for an F line; nC represents a refractive index of the respective optical material, for a C line; and Tg represents a transition point of the glass (Â°C.).