Infrared cut-off filter and lens module

Abstract

The invention provides an infrared cut-off filter which comprises a substrate and an infrared cut-off film. The infrared cut-off film is plated on the substrate. The substrate is made of sapphire. The infrared cut-off film is used for filtering infrared light rays in light rays, a film system structure of the infrared cut-off film is (xHyL)<eta>, the eta is larger than or equal to 30 and is smaller than or equal to 80, the x is larger than 1 and is smaller than 2, the y is larger than 1 and is smaller than 2, the eta is a positive integer, the H represents layers with high refractive indexes and the thicknesses equal to 1 / 4 of the central wavelength, the L represents layers with low refractive indexes and the thicknesses equal to 1 / 4 of the central wavelength, xH represents layers with high refractive indexes and the thicknesses equal to x / 4 of the central wavelength, yL represents layers with high refractive indexes and the thicknesses equal to y / 4 of the central wavelength, and the eta is the number of stacked cycles of the layers with the high refractive indexes and the layers with the low refractive indexes. The infrared cut-off filter has the advantage that the infrared cut-off film is plated on the substrate made of the sapphire, so that an infrared filtering effect of the sapphire substrate can be effectively improved. The invention further provides a lens module comprising the infrared cut-off filter.

Description

technical field [0001] The invention relates to an optical element, in particular to an infrared cut-off filter and a lens module using the infrared cut-off filter. Background technique [0002] Sapphire is widely used in imaging systems due to its high hardness and high wear resistance. However, sapphire has high transmittance to infrared light, and if the infrared light cannot be filtered, the imaging quality of the imaging system will be degraded. Contents of the invention [0003] In view of this, it is necessary to provide an infrared cut-off filter using sapphire as a substrate and a lens module using the infrared cut-off filter that can improve the imaging quality. [0004] An infrared cut-off filter, which includes a substrate and an infrared cut-off film. The substrate includes an upper surface and a lower surface opposite to the upper surface, and the infrared cut-off film is plated on the upper surface. The substrate is made of sapphire. The infrared cut-off...

AI Technical Summary

Problems solved by technology

However, sapphire has a high transmittance to infrared light, and if the infrared light cannot be filtered, the imaging quality of the imaging system will be degraded

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