Uniform reflectance optical mirror
US5438446A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1993 |
| Grant date | Aug 1, 1995 |
| Priority date | — |
| Expiry date | Feb 23, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/0816
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A uniform reflectance mirror deflector of an optical scanner for scanning a light beam onto an image object or a receiving medium. The scanner includes a rotatable polygon-shaped mirror having a plurality of planes reflective mirror facets for deflecting and thereby scanning the beam through a predetermined angle while rotating and thereby varying the angle of incidence of the light beam on the deflector. In order to achieve relative uniformity of reflectance and avoid intensity variations in the reflected beam, a protective optical coating layer is selected to have a thickness which minimizes variation in reflectance over the range of angular displacement of the mirror in relation to the light source during its rotation. The thickness of the protective coating layer uniformly applied over the entire surface of each facet of the polygon-shaped mirror is determined by calculating the reflectance of P-polarized and S-polarized incident radiation components at a predetermined wave length of incident radiation over a range of protective coating film thicknesses of between 0 and one wave length and over the range of angles of incidence. Coating thicknesses in this range are selected in …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.