Infrared-cut filter with sapphire substrate and lens module including the infrared-cut filter

摘要

An IR-cut filter includes a substrate and an infrared filtering film. The substrate is made of sapphire, and includes a first surface and a second surface opposite to the first surface. The infrared filtering film covers the first surface of the substrate and increases the reflectivity in relation to infrared light, thus filtering out the infrared light. The infrared filtering film includes a number of first high refraction index layers and a number of first low refraction index layers alternately stacked on the first surface of the substrate.

主权项

1. An IR-cut filter, comprising:
a substrate made of sapphire, a refraction index of the sapphire is from about 1.747 to about 1.760, a growth direction of the sapphire is a-axis (11 20), c-axis (0001), and m-axis (10 10), and the substrate comprising a first surface and a second surface opposite to the first surface; and an infrared filtering film covering on the first surface of the substrate and configured for filtering the infrared lights, the infrared filtering film comprising a number of first high refraction index layers and a number of first low refraction index layers alternately stacked on the first surface of the substrate; wherein the infrared filtering film is represented by (xHyL)η, where η is a positive integer and in a range that 30≦η≦80, x meets the formula that 1