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US 6,617,002 B2Granted
Microperforated polymeric film for sound absorption and sound absorber using same
AssigneeMinnesota Mining and Manufacturing Company
InventorKenneth Brian Wood
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Abstract
Microperforated polymeric films and sound absorbers using such films are provided. The microperforated polymeric films may be relatively thin and flexible and may further include holes having a narrowest diameter less than the film thickness and a widest diameter greater than the narrowest diameter. The microperforated polymeric films of a sound absorber may also have relatively large free span portions, which, in certain embodiments, may vibrate in response to incident sound waves.
Claims26
A microperforated polymeric film sound absorber, comprising:
- a surface;
- and
- a microperforated polymeric film having a bending stiffness of 107 dyne-cm or less disposed near the surface such that the film and the surface define a cavity therebetween, the film including a plurality of microperforations having a narrowest diameter of 20 mils or less and a relatively large free span portion spanning at least part of the cavity;
- wherein the relatively large free span portion has a length of about 100 mils or more;
- wherein the sound absorber does not include other microperforated films.
2 more elements
A sound absorber, comprising:
- a surface;
- a microperforated film disposed near the surface such that the film and the surface define a cavity therebetween, the film including a plurality of microperforations having a narrowest diameter of 20 mils or less;
- and
- a thermoplastic sound absorbing fibrous material disposed adjacent the microperforated film.
1 more element
Dependencies are inferred from the claim text.