Optical interference structures incorporating porous films
US5218472A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1992 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Jan 28, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12042
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Optical interference structures incorporating porous films are disclosed. These structures are capable of exhibiting a color by interference effects caused by the interference of light reflected from various layers within the structure. Basically, the structures comprise a reflective substrate, a porous transparent dielectric film on the substrate and at least one semi-transparent layer supported by the porous dielectric film. The structure is such that there are at least two reflective surfaces separated by an optically thin porous layer of the dielectric film. These structures can be formed by several methods, but the most convenient involves the porous anodization of a substrate metal (e.g. aluminum) to form the dielectric film and the deposition of a semi-transparent metal layer within the pores or on the film surface. The structures can be made inexpensively and are capable of generating strong and, if desired, dichroic colors. The porous nature of the film can also be exploited to create color shifts. The structures can be used for decorative purposes or to create a wide range of indicators, sensors, security devices and the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.