Device for treating substrates, in particular for perforating paper
US5684617A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 15, 1996 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Mar 15, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K26/0846
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
In a device for perforating cigarette paper strips, a row of adjacent optical elements (28) is disposed in the ray path of a laser beam deflected by a rotating mirror (12). Each of the optical elements includes a diffractive optical element (DOE) (24'; 24"; 24'") and a convergent lens (18'; 18"; 18'"). A parallel bundle of laser rays hits the surface of the DOE, and the DOE emits one or more bundles of rays with a desired configuration. The convergent lens produces therefrom in the plane of the cigarette paper strip (20) one or more focal spots, for example two or four mutually offset focal spots (22a, 22b) or a ring focus, so that one can form not only microperforations by individual focal spots but also macroperforations by applying energy to only the peripheral area of a macroperforation rather than the entire perforation area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.