Illumination system having an intensity calibration system
US6188427A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1998 |
| Grant date | Feb 13, 2001 |
| Priority date | — |
| Expiry date | Apr 20, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/465
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An illumination system (10) having an automated calibration system (62) for adjusting the light intensity of individual elements (14) of an array of light emitting elements (12). An optical sensor (30) can be positioned in several locations (A,B,C) to sense incident light from a spatial light modulator (20) as the modulator is sequentially actuated one zone (50) at a time. The light output from each zone (50) of the spatial light modulator is characterized and compared to a golden standard, and the light emitting elements of the array associated with illuminating the zones that are deficient in light are ascertained. Adjustment circuitry (62) responsively adjusts and increases the drive current to the associated light emitting elements (14) that are deficient in light output. A look-up table is utilized to determine which LEDs (14) need adjustment to their drive currents to insure uniform illumination in the process and cross-process direction at an image plane. The present invention is ideally suitable for xerographic printers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.