| # | Country | Total Patents | |
|---|---|---|---|
| #1 | United States | 13 |
| # | Industry | |
|---|---|---|
| #1 | Audio-visual technology | |
| #2 | Basic communication technologies | |
| #3 | Optics | |
| #4 | Electrical machinery and energy |
| # | Technology | |
|---|---|---|
| #1 | Amplifiers | |
| #2 | Loudspeakers and microphones | |
| #3 | Cameras | |
| #4 | Special information storage | |
| #5 | Electric discharge tubes | |
| #6 | Modulation | |
| #7 | Photosensitive materials |
| # | Name | Total Patents |
|---|---|---|
| #1 | Josef Engl | 13 |
| #2 | Joseph Massolle | 12 |
| #3 | Hans Vogt | 11 |
| Publication | Filing date | Title |
|---|---|---|
| US1585333A | Telephone | |
| US1557678A | Acoustic-cinematographic apparatus | |
| US1512681A | Production of sound-record photographic positives | |
| US1555301A | Amplifier coupling | |
| US1634201A | Glow-discharge tube | |
| US1550381A | Electrostatic telephone | |
| US1590185A | Light source and light-sensitive coating for phonocinematography | |
| US1566413A | Means for recording sound waves | |
| US1558032A | Arrangement for acoustic cinematography | |
| US1630753A | Amplifier | |
| US1587786A | Electron tube |