http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-1414978-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_294881271413951a95f284b588a68e66 |
| classificationCPCAdditional | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01L2224-48472 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01L2224-73265 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01L2224-023 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01L2924-01322 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01L2924-3025 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01L2924-3011 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01G7-025 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/H04R19-00 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/H01G7-02 |
| filingDate | 1972-12-01-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1975-11-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-1414978-A |
| titleOfInvention | Electretand a method of making the same |
| abstract | 1414978 Electrets SONY CORP 1 Dec 1972 [2 Dec 1971] 14703/75 Divided out of 1414977 Heading H1M An electret comprises an electrically conductive substrate having on one surface thereof superposed, contiguous first and second layers of different inorganic insulating materials, said layers of inorganic insulating material carrying a permanent charge. After being deposited, the inorganic material is charged, preferably by subjecting it to electron beam radiation or other charged particle radiation, or by diffusion of sodium or potassium into it, or by applying a direct voltage between the substrate and the exposed surface of the insulating layer. Preferably the electret structure is made using aluminium sheet 24, thickness 2 mm. (Fig. 6c) on which is vapour deposited gold of thickness 0À1 Á. On top of this layer is deposited an inorganic insulator 27 in two layers, e.g. of silicon dioxide, aluminium oxide, titanium dioxide, silicon nitride, or an adduct of phosphorus pentoxide and silicon dioxide, layer 27 is then exposed to an electron beam to permanently charge it. For example, a layer of aluminium oxide of thickness 1500 Š to 2000 Š and a layer of silicon dioxide of thickness 100 Š to 300 Š are successively vapour deposited, whereupon the two layers are charged. Another combination of two layers consists of silicon nitride and silicon dioxide. After the layer 27 has been charged, a further layer 28 of metal (e.g. aluminium of thickness about 10 Á) is vapour deposited. Subsequently holes 29, 31 (Figs. 6D) are etched chemically through the metal layers 24, 28 to leave a deformable central area consisting of electret material 27 and gold 26. Thereafter, individual electret structures are cut out of a large sheet by cutting along lines 32 to form circular structures of diameter to suit an electret transducer such as a microphone. Remainder portions 24, 28 support the diaphragm layers 26, 27. Microphones utilizing the electrets are claimed in Specification 1,414,977. |
| priorityDate | 1971-12-02-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 39.