An incident angle insensitive color filter and its manufacturing method

Patent metadata

Field	Value
Publication number	US-2016274282-A1
Application number	US-201414412361-A
Country	US
Kind code	A1
Filing date	Jan 2, 2014
Priority date	Dec 13, 2013
Publication date	Sep 22, 2016
Grant date	—

Abstract

An incident angle insensitive color filter is disclosed, comprising a substrate, wherein several cylindrical gratings, made of silicon, are arranged in a regular hexagon shape on the substrate which is made up of fused quartz. A manufacturing method of the aforesaid filters is also disclosed. Different from the traditional chemical filters and traditional interference filters, incident angle insensitive color filters in the present invention are based on two-dimensional grating structure and make use of the huge refractive index contrast in the grating layer, by which the resonance is excited the resonance via the coupling between the regions with high/low refractive index, so as to achieve the incident angle insensitive filtering effects. The manufacturing method of incident angle insensitive color filters in the present invention is simple and of low cost, which is suitable for large scale mass manufacture. Therefore, the present invention is expected to be extensively applied in the fields of liquid crystal display, color printing, sensor detecting, anti-counterfeiting and so forth.

First claim

1 . An incident angle insensitive color filter, comprising a substrate ( 2 ), wherein several cylindrical gratings ( 1 ), made of silicon, are arranged in a regular hexagon shape on the substrate ( 2 ) which is made of fused quartz.

2 . The incident angle insensitive color filter as claimed in claim 1 , wherein the gratings ( 1 ) are perpendicular to the substrate ( 2 ); the thickness of the gratings ( 1 ) is 70-200 nm; the cylindrical radius of the gratings ( 1 ) is 40-90 nm; and the center distance between the cylindrical gratings ( 1 ) is 100-280 nm.

3 . A manufacturing method of the incident angle insensitive color filter as claimed in claim 1 , wherein the following steps are comprised:
(1) obtaining the thickness, the cylindrical radius and the center distance of cylindrical gratings corresponding to the central wavelength of the filter to be fabricated by optimization; (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 the 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, clean and obtain 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 fix 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, transfer the two-dimensional grating template to the bottom silicon layer, thus the required two-dimensional grating is made. Then use 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.

4 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 3 , wherein the annealing conditions in step (2) are: rapid annealing under 1000-1100° C. for 15-25 seconds first, then annealing under 550-650° C. for 20-25 hours, and at last annealing under 850-950° C. for 15-25 hours.

5 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 4 , wherein the annealing conditions in step (2) are: rapid annealing under 1050° C. for 20 seconds first, then annealing under 600° C. for 24 hours, and at last annealing under 900° C. for 20 hours.

6 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 3 , wherein the aluminum foil in step (3) is high purity aluminum foil of 99.999%.

7 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 3 , wherein the oxides are titanium dioxide, hafnium dioxide or tantalum pentoxide.

8 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 7 , wherein the oxides are titanium dioxide.

9 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 3 , wherein the reactive ion etching conditions in step (12) are: the volume flow rate of carbon tetrafluoride is 20-30 sccm, and the volume flow rate of oxygen is 3-6 sccm.

10 . The manufacturing method of the incident angle insensitive color filter as claimed in claim 9 , wherein the reactive ion etching conditions are: the volume flow rate of carbon tetrafluoride is 25 sccm, and the volume flow rate of oxygen is 3.1 sccm.

11 . A manufacturing method of the incident angle insensitive color filter as claimed in claim 2 , wherein the following steps are comprised:
(1) obtaining the thickness, the cylindrical radius and the center distance of cylindrical gratings corresponding to the central wavelength of the filter to be fabricated by optimization; (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 the 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, clean and obtain 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 fix 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, transfer the two-dimensional grating template to the bottom silicon layer, thus the required two-dimensional grating is made. Then use 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.

Assignees

• Univ Zhejiang

Inventors

• Shen Weidong
• Yang Chenying
• Zhang Yueguang
• Liu Xu

Classifications

• G02B1/02

  made of crystals, e.g. rock-salt, semi-conductors (G02B1/08 takes precedence) · CPC title

• G02B5/1819

  Plural gratings positioned on the same surface, e.g. array of gratings (plural diffractive elements positioned sequentially along the optical path G02B27/4272) · CPC title

• G02B5/207 Primary

  comprising semiconducting materials · CPC title

• G02B5/201

  in the form of arrays · CPC title