LED printhead temperature compensation
US4952949A · kind A · utility
43Cited by
5References
25Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 28, 1989 |
| Grant date | Aug 28, 1990 |
| Priority date | — |
| Expiry date | Nov 28, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/1247
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The light output of light emitting diodes on an LED printhead for a photosensitive printer is temperature compensated so that light output remains constant regardless of temperature changes of the LED chips. An LED chip has a plurality of exposure LEDs and a dummy LED. The voltage across the dummy LED is sensed and combined with an adjustable reference voltage. This provides the input to an op-amp, the output of which provides a chip reference voltage which controls the current to the LEDs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.