http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-1395256-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_d0cb7734bc2e5840db630f0ae7c29684 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01G7-023 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H04R19-01 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/H04R19-01 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/H01G7-02 |
| filingDate | 1972-06-28-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1975-05-21-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-1395256-A |
| titleOfInvention | Electrets |
| abstract | 1395256 Electrets AGENCE NATIONALE DE VALORISATION DE LA RECHERCHE 28 June 1972 [2 July 1971] 30281/72 Heading H1M [Also in Division H4] Leakage of charge from the charged surface, or as shown, surfaces of a polymer electret is avoided by sealing a fluid 10 of high dielectric strength so that it is in substantially permanent contact with the charged surface. As shown this is achieved by peripherally sealing further polymer sheets 11, 16 to the electret foil 3. High dielectric strength is defined as being higher than that of pure dry air binder normal conditions, and suitable fluids are carbon tetrachloride, sulphur hexafluoride, liquid nitrogen, air at less than one millibar and trihalomethanes. To manufacture the electret a foil of polypropylene or polyimide is placed between two electrodes and a voltage sufficient to ionize air trapped between the surface to be charged and the electrode is applied. Where only one surface is to be charged air in contact with the other surface is replaced by insulating oil, or that surface is metallized. The electrodes are then moved away while the voltage is maintained, the ambient air is replaced, in a suitable chamber by the fluid of high dielectric strength a dielectric foil is placed in contact with each charged surface and the peripheral welding carried out. The electrets are suitable for use in microphones, telephone receivers or transmitters, pick-ups or ultrasonic transducers. |
| priorityDate | 1971-07-02-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 18.