Illumination obscurement device
US6220730A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 1998 |
| Grant date | Apr 24, 2001 |
| Priority date | — |
| Expiry date | Jul 1, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An illumination obscurement device for controlling the obscurement of illumination from a light source which is optimized for use with a rectangular, arrayed, selective reflection device. In a preferred embodiment, a rotatable shutter with three positions is placed between a light source and a DMD. The first position of the shutter is a mask, preferably an out of focus circle. This out of focus circle creates a circular mask and changes any unwanted dim reflection to a circular shape. The second position of the shutter is completely open, allowing substantially all the light to pass. The third position of the shutter is completely closed, blocking substantially all the light from passing. By controlling the penumbra illumination surrounding the desired illumination, DMDs can be used in illumination devices without creating undesirable rectangular penumbras.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.