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.