The invention provides a multispectral
coating method for a linear gradual change
optical filter and the linear gradual change
optical filter, and the method comprises the steps: S1, putting
optical glass into a
cleaning agent for ultrasonic cleaning, and obtaining a substrate of the linear gradual change
optical filter to be coated; s2, putting the substrate into a reaction cavity of a
radio frequency magnetic control instrument, closing the reaction cavity, and setting environmental parameters of multispectral
coating; s3, under the environmental parameters,
sputtering and depositing target materials on the surface of the substrate by adopting double-target-position
radio frequency magnetic control, using SiO2 and Si as the target materials for the double target positions respectively, and switching to use different target positions to alternately carry out
sputtering deposition of the target materials by adjusting the power interval of the
radio frequency magnetic control; and S4, closing the radio frequency magnetic control instrument, keeping the reaction cavity closed, naturally cooling to a preset
cooling temperature, opening the reaction cavity, and taking out the coated substrate as the linear gradual change optical filter. The process is simple, and the optical filter finished product is good in
infrared spectrum performance and suitable for various scenes.