Raster display apparatus
US4308532A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1979 |
| Grant date | Dec 29, 1981 |
| Priority date | — |
| Expiry date | Dec 3, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/227
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A raster display apparatus capable of displaying graphic pictures includes a processor 13 for loading character codes (pointers) in a character buffer 12. The pointers address a character/cell generator 22 to derive the bit patterns necessary to refresh the display 1 under control of refresh logic 19. As the picture becomes increasingly complex, requiring more and more different character cells, the character/cell generator 22 fills. Space is created by combining two or more adjacent cells into a single low-resolution-displayed cell: an op code associated with each character code (pointer) determines whether the cell is to be displayed at full or reduced resolution and causes the refresh logic to clock bit patterns associated with low resolution cells at a slower rate. Optionally, the processor 13 changes low resolution parts of the picture to high resolution when an operator interacts with the low resolution part using a light pen 30.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.