Microprism master mold
US6120280A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1998 |
| Grant date | Sep 19, 2000 |
| Priority date | — |
| Expiry date | Jan 28, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/03
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A microprism master mold is formed from a plurality of flat sheets having two mutually parallel major surfaces. On one edge thereof, there is provided a series of V-shaped grooves having a bottom angle of about 90.degree. and roof-shaped projections having a vertical angle of about 90.degree., successively formed at a fixed repeating pitch and in a direction perpendicular to the major surfaces. The flat sheets are stacked so that the vertices of the roof-shaped projections formed on each flat sheet meet the bottoms of the V-shaped grooves formed on an adjacent flat sheet. The microprism master mold includes two or more different types of roof-shaped projections and the thickness of each flat sheet is equal to 0.6-2.0 times the length of the shorter oblique sides of the roof-shaped projections. The master mold is useful for production of cube-corner type retroreflectors characterized by microprism having high brightness and excellent wide-angle properties. The retroreflective sheeting produced with the microprism master mold may be thin and flexible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.