Light emitting diode signs and translucent plastic sheets used therein
US6878436B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 2003 |
| Grant date | Apr 12, 2005 |
| Priority date | — |
| Expiry date | Oct 14, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/26
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Disclosed is a polished translucent co-extruded sheet having utility as a light diffusing protective cover or sign face for light emitting diode (LED) light sources and other purposes. The sheet is comprised of (a) a particle layer containing particles having a mean particle size of about 4 to 100 microns and having a particle size distribution of between 1-110 microns, at a loading of 1 to 60% melt blended with a thermoplastic matrix, wherein the particle and matrix have refractive indices that differ by greater than 0.001 units of each other when measured in conformance with ASTM D 542; and (b) at least one substrate layer comprised of thermoplastic compositions, wherein the substrates have a refractive index within 0.2 units of the refractive index of the particle layer matrix when measured in conformance with ASTM D 542.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.