Electrical Research Products Inc
ElectricalActive Patents
0
Total Holdings
8
Patent Holdings
Filter in Explorer →| Patent No. | Title | Status | Filing Date | Grant Date | Claims | Actions |
|---|---|---|---|---|---|---|
| US2267690A | Photoelectric cell circuit | Expired / Lapsed | 1937-12-21 | 1941-12-23 | 0 | Details |
| US2249606A | Stereophonic sound recording system | Expired / Lapsed | 1938-03-22 | 1941-07-15 | 0 | Details |
| US2008881A | Motion picture projecting and sound reproducing apparatus | Expired / Lapsed | 1931-06-01 | 1935-07-23 | 0 | Details |
| US1970358A | Translucent optical projection screen | Expired / Lapsed | 1932-01-28 | 1934-08-14 | 0 | Details |
| US1953471A | Optical instrument | Expired / Lapsed | 1932-01-05 | 1934-04-03 | 0 | Details |
| US1939074A | Sound picture recording system | Expired / Lapsed | 1931-02-27 | 1933-12-12 | 0 | Details |
| US1814263A | Electrical control system | Expired / Lapsed | 1927-04-01 | 1931-07-14 | 0 | Details |
| US1795626A | Camera | Expired / Lapsed | 1927-05-14 | 1931-03-10 | 0 | Details |