Apparatus for use in determining a characteristic of a cathode ray tube
US4021724A · kind A · utility
1Cited by
2References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1975 |
| Grant date | May 3, 1977 |
| Priority date | — |
| Expiry date | Dec 29, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/42
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Test apparatus for a cathode ray tube has optical elements disposed along two optical paths from the screen of a cathode ray tube to two photosensors. One optical path passes through a graticule which has a pattern of light transmissive and non-transmissive areas. The real image of a luminous spot on the screen is accurately positioned on a boundary between two of the areas of the graticule by deriving a control signal from a comparison of the photosensor outputs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.