Linear integrating cavity light source for infra-red illumination of sensitized media
US5548120A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1994 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Nov 14, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8908
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A highly uniform infrared illumination source for illuminating a stripe of a moving sensitized web for line scan imaging of imperfections in the coating on the web by a CCD imaging camera. A light integrator having an elongated housing formed with side and end walls defines a linear light integrating cavity having diffusely reflecting interior wall surfaces. An elongated array of infrared LEDs is spaced along the side wall for emitting light into the cavity for integration within the cavity. A longitudinally extending slit is formed in the side wall through which a diffuse, linear light beam exits the elongated slit having a varying longitudinal intensity profile. The intensity of the light emitted by the LEDs is modulated in an intensity pattern that alters the varying longitudinal intensity profile of the linear light beam to provide a desired longitudinal intensity profile of the stripe of diffuse illumination. Preferably, the intensity modulation renders more uniform the longitudinal intensity profile of the linear light beam illuminating the web as viewed by the imaging camera. The desired light intensity profile along the length of the emitted light beam is achieved by cluste…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.