Patent ID: 9625627
Date: 2017-04-18
CPC Classifications: G02B

Claim:
1. A manufacturing method of an incident angle insensitive color filter comprising a substrate, wherein several cylindrical gratings, made of silicon, are arranged in a regular hexagon shape on the substrate which is made of fused quartz; the manufacturing method comprising following steps: (1) obtaining thickness, cylindrical radius and center distance of cylindrical gratings corresponding to central wavelength of the filter to be fabricated; (2) depositing a layer of silicon on the fused quartz substrate and anneal, wherein the thickness of the silicon layer equals to the thickness of the grating; (3) preprocessing an aluminum foil; (4) anodizing the preprocessed aluminum foil twice and obtaining orderly arranged porous alumina, wherein the pore radius equals to the cylindrical radius of gratings and the pore center distance equals to the center distance of cylindrical gratings; (5) spin-coating a layer of polymethyl methacrylate on the porous alumina as the protective layer for removing the aluminum substrate; (6) removing the aluminum substrate in the mixed solution of copper sulfate and hydrochloric acid, cleaning and obtaining a porous alumina template frame coated with a protective layer; (7) using oxygen plasma to bombard the silicon layer with fused quartz substrate, and then fixing the porous alumina template frame onto the silicon layer with fused quartz substrate in step (2); (8) removing the polymethyl methacrylate layer on the porous alumina template frame; (9) atomic layer depositing oxide on the orderly arranged porous alumina template frame; (10) using reactive ion etching to remove the oxide layer covered on the surface of porous alumina; (11) using KOH solution to remove the porous alumina template frame, showing the outline of the required two-dimensional grating which is composed of cylindrical oxide columns orderly arranged in a regular hexagon shape; (12) using reactive ion etching to etch the oxide columns and the silicon layer simultaneously, transferring the two-dimensional grating template to the bottom silicon layer, thus the required two-dimensional grating is made, then using wet etching to remove the residual oxide columns and obtain an incident angle insensitive color filter, wherein the gratings are cylindrical, arranged in regular hexagon and made up of silicon.