OPTICAL FILTER, SENSOR SYSTEM COMPRISING SAME, AND METHOD FOR MANUFACTURING HALOGENATED AMORPHOUS SILICON THIN FILM FOR OPTICAL FILTER
According to the present invention, provided are: an optical filter capable of exhibiting low extinction coefficient characteristics in a narrowband of approximately 800 nm-1100 nm while having a high refractive index; and a sensor system comprising same.
1 . An optical filter comprising:
a first mirror layer where a first high refraction material layer and a first low refraction material layer are alternately deposited;
a spacer layer continuously deposited above one side surface of the first mirror layer, and comprises a plurality of second high refraction material layers; and
a second mirror layer located to face the first mirror layer with the spacer layer interposed therebetween, and where a third high refraction material layer and a third low refraction material layer are alternately deposited, and
wherein in a wavelength range of 800 nm to 1100 nm, one or more of the first high refraction material layer, the second high refraction material layer, and the third high refraction material layer comprising a silicon material with amorphous property, have a refractive index of 3.0 or more, and an optical extinction coefficient of 0.001 or below, and wherein the silicon material comprises H, Si, or a halogen element.
2 . The optical filter according to claim 1 ,
wherein a ratio of (optical thickness of the first high refraction material layer/optical thickness of the first low refraction material layer) or (optical thickness of the third high refraction material layer/optical thickness of the third low refraction material layer) is 1.5 to 3.0.
3 . The optical filter according to claim 1 ,
wherein the halogen element comprises F or Cl.
4 . The optical filter according to claim 2 ,
wherein the optical filter has a transmission band of a wavelength range of 800 nm to 1100 nm, and a central wavelength of 950 nm is band shifted to below 25 nm at most according to an incidence angle change of 0 to 45 degrees.
5 . The optical filter according to claim 2 ,
wherein the optical filter has a transmission band of a wavelength range of 800 nm to 1100 nm, and a central wavelength of 950 nm is band shifted to below 38 nm at most according to an incidence angle change of 0 to 60 degrees.
6 . The optical filter according to claim 1 ,
wherein the first high refraction material layer, the second high refraction material layer, and the third high refraction material layer have a refractive index identical to one another, and
the first low refraction material layer and the third low refraction material layer have a refractive index identical to each other.
7 . The optical filter according to claim 1 ,
wherein the silicon material is prepared using a PVD method comprising a step of introducing an inert gas, a halogen gas and a carrier gas into a chamber, and
a ratio of volume of the halogen gas/(volume of the halogen gas+volume of the carrier gas) being introduced into the chamber during a same period of time is above 0 and below 0.375.
8 . The optical filter according to claim 1 ,
wherein the first low refraction material layer and the third low refraction material layer comprises one or more of TiO2, Nb2O5, Ta2O5, Si3N4, SiO2, MgF2, Al2O3, halogenated amorphous silicon compound, or a mixture thereof.
9 . The optical filter according to claim 1 ,
wherein a ratio of (optical thickness of the first high refraction material layer/optical thickness of the first low refraction material layer) or (optical thickness of the third high refraction material layer/optical thickness of the third low refraction material layer) is 1.5 to 3.0, thereby causing a central wavelength to be band shifted to below 25 nm according to an incidence angle change of 0 to 45 degrees.
10 . A sensor system comprising:
an optical filter that includes
a first mirror layer where a first high refraction material layer and a first low refraction material layer are alternately deposited;
a spacer layer continuously deposited above one side surface of the first mirror layer, and comprises a plurality of second high refraction material layers; and
a second mirror layer located to face the first mirror layer with the spacer layer interposed therebetween, and where a third high refraction material layer and a third low refraction material layer are alternately deposited, and
wherein in a wavelength range of 800 nm to 1100 nm, one or more of the first high refraction material layer, the second high refraction material layer, and the third high refraction material layer comprising a silicon material with amorphous property, have a refractive index of 3.0 or more, and an optical extinction coefficient of 0.001 or below, and wherein the silicon material comprises H, Si, or a halogen element; and
a light source emitting light of a wavelength range of 800 nm to 1100 nm in order to generate a reflected light reaching the optical filter; and
a sensor disposed on a processing path of the reflected light passing through the optical filter, and receives 3D information about a subject, included in the reflected light.