Diffusing sheet, surface light source unit, and transmission type display
US7408708B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 2005 |
| Grant date | Aug 5, 2008 |
| Priority date | — |
| Expiry date | Nov 23, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133607
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A diffusing sheet, a surface light source unit, and a transmission type display that can attain uniform illumination so that the brightness of light on the display screen appears uniform regardless of the position from which the display screen is observed. The diffusing sheet includes, on its light-emerging side surface, a diffusion lens array having a plurality of unit lenses, each unit lens being in a shape equivalent to a part of an elliptic cylinder having an elliptical cross section. The surface light source unit includes the diffusing sheet and a convergent sheet 12 that has a plurality of unit lenses 121 having almost trapezoidal cross sections, formed on one surface thereof. It is possible to attain uniform illumination by diffusing light from cathode ray tubes in the surface light source unit, and, at the same time, to converge the light serving as backlight to enhance optical efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.