NIPPON TELEGRAPH AND TELEPHONE CORPORATION
5,399Patents
3,711Active
5,399Granted
60Portfolio score
Filing activity: Oct 20, 1976 → Jun 14, 2024 · 406 expiring within 5 years
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US8405773B2 | Video communication quality estimation apparatus, method, and program | Electricity | 443 | Active |
| US4977595A | Method and apparatus for implementing electronic cash | Electricity | 363 | Expired |
| US6233578A | Method and system for information retrieval | Emerging Cross-Sectional Technologies | 297 | Expired |
| US5280537A | Digital communication system using superposed transmission of high speed and low speed digital signals | Electricity | 296 | Expired |
| US8548294B2 | Optical fiber cable and optical fiber ribbon | Physics | 281 | Active |
| US5736982A | Virtual space apparatus with avatars and speech | Electricity | 279 | Expired |
| US5581652A | Reconstruction of wideband speech from narrowband speech using codebooks | Physics | 276 | Expired |
| US5933506A | Transmitter-receiver having ear-piece type acoustic transducing part | Electricity | 261 | Expired |
| US5617537A | Message passing system for distributed shared memory multiprocessor system and message passing method using the same | Physics | 255 | Expired |
| US6920166B2 | Thin film deposition method of nitride semiconductor and nitride semiconductor light emitting device | Electricity | 247 | Expired |
| US5293448A | Speech analysis-synthesis method and apparatus therefor | Physics | 247 | Expired |
| US5718628A | Air conditioning method in machine room having forced air-cooling equipment housed therein | Emerging Cross-Sectional Technologies | 243 | Expired |
| US6788865B2 | Polarization maintaining optical fiber with improved polarization maintaining property | Physics | 231 | Expired |
| US5214730A | Multifiber optical connector plug with low reflection and low insertion loss | Physics | 230 | Expired |
| US6185312A | Method for embedding and reading watermark-information in digital form, and apparatus thereof | Electricity | 223 | Expired |
| US5911008A | Scheme for detecting shot boundaries in compressed video data using inter-frame/inter-field prediction coding and intra-frame/intra-field coding | Electricity | 222 | Expired |
| US6542171B1 | Scheme for graphical user interface using polygonal-shaped slider | Human Necessities | 222 | Expired |
| US5751452A | Optical devices with high polymer material and method of forming the same | Physics | 207 | Expired |
| US6226614A | Method and apparatus for editing/creating synthetic speech message and recording medium with the method recorded thereon | Physics | 205 | Expired |
| US5926548A | Method and apparatus for implementing hierarchical electronic cash | Electricity | 203 | Expired |
| US5999975A | On-line information providing scheme featuring function to dynamically account for user's interest | Physics | 201 | Expired |
| US5576950A | Video image search method and system using the same | Electricity | 197 | Expired |
| US6222583A | Device and system for labeling sight images | Physics | 196 | Expired |
| US5317405A | Display and image capture apparatus which enables eye contact | Electricity | 194 | Expired |
| US5748775A | Method and apparatus for moving object extraction based on background subtraction | Electricity | 190 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.