Aberration-free directional image window sheet
US5933276A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 18, 1998 |
| Grant date | Aug 3, 1999 |
| Priority date | — |
| Expiry date | May 18, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E10/40
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
There is disclosed a partially transparent, directional viewing sheet formed of plastic material with convex and concave lenses of elliptical cross-section, preferably lenticular lenses, formed respectively on the front and back surfaces of the sheet, there being intervening spaces with convex surfaces between the concave lenses which spaces are not transparent to images and may be imprinted with an image that is viewable through the sheet from some directions. Preferably the concave lens focal length is typically about one-half of the focal length of the convex lens. Elliptical cross-section of the lenses minimizes spherical aberration and sharpens the focus. The thickness of the sheet causes focal points of the lenses to substantially coincide producing the effect of a tiny Galilean telescope. The view through such a sheet in a direction substantially aligned with the optical axis of the tiny telescope is a minimally distorted view of objects distant from or near to the opposite side of the sheet while off-axis viewing will present the image imprinted on the intervening convex surfaces between the concave lenses on the back surface of the sheet. Such convex surfaces are preferred…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.