Apparatus and a method for illuminating a light-sensitive medium

Abstract

A system for illumination of a light sensitive medium includes means for patterning each of a plurality of beams using an illumination unit having at least one illumination head, the illumination head including at least two arrays of individually controllable light valves, means for projecting the patterned beams onto the light sensitive medium, means for displacing the light sensitive medium relative to the patterned beams, such that the patterned beams are scanned across the light sensitive medium in a scanning direction, means for directing the patterned beams towards the light sensitive medium by means of lenses arranged such that each lens directs a respective part of a respective patterned beam towards a respective target area on the light sensitive medium, means for spacing the arrays apart in the scanning direction, such that each of the arrays scans the patterned beams across the areas of the light sensitive medium as the light sensitive medium and the at least one illumination head are displaced relative to each other, the respective target areas scanned by the patterned beams are contiguous, means for individually controlling the individually controlled light valves of the illumination unit in dependency of the relative movement between the illumination head and the light sensitive medium, and a plurality of light emitters in the form of light guides arranged to illuminate the light sensitive medium via a light valve arrangement, the light valve arrangement including a plurality of electrically controlled light valves, wherein at least two of the light emitters are arranged to illuminate a plurality of light valves each.

1 . A system for illumination of a light sensitive medium comprising:
 means for patterning each of a plurality of beams using an illumination unit comprising at least one illumination head, the illumination head comprising at least two arrays of individually controllable light valves;   means for projecting the patterned beams onto the light sensitive medium; and   means for displacing the light sensitive medium relative to the patterned beams, such that the patterned beams are scanned across the light sensitive medium in a scanning direction;   means for directing the patterned beams towards the light sensitive medium by means of lenses arranged such that each lens directs a respective part of a respective patterned beam towards a respective target area on the light sensitive medium;   means for spacing said arrays apart in the scanning direction, such that each of the arrays scans the patterned beams across the areas of the light sensitive medium as the light sensitive medium and the at least one illumination head are displaced relative to each other, the respective target areas scanned by the patterned beams are contiguous;   means for individually controlling the individually controlled light valves of said illumination unit in dependency of the relative movement between the illumination head and the light sensitive medium; and   a plurality of light emitters in the form of light guides arranged to illuminate the light sensitive medium via a light valve arrangement, said light valve arrangement comprising a plurality of electrically controlled light valves, wherein at least two of the light emitters are arranged to illuminate a plurality of light valves each.   
     
     
         2 . A system for illumination of a light sensitive medium according to  claim 1 , wherein the patterned beams are projected to an projection area on the light sensitive medium and wherein the projection area forms a square shape. 
     
     
         3 . A system for illumination of a light sensitive medium according to  claim 1 , wherein said illumination head comprises a scanning rod whose relative movement with the light sensitive medium is a single progressing movement in the transverse direction of the scanning rod. 
     
     
         4 . A system for illumination of a light sensitive medium according to  claim 3 , wherein said scanning rod comprising at least two illumination heads each illuminating part of the light sensitive medium. 
     
     
         5 . A system for illumination of a light sensitive medium according to  claim 3 , wherein said scanning rod comprising at least two illumination heads each illuminating different parts of the light sensitive medium. 
     
     
         6 . A system for illumination of a light sensitive medium according to  claim 1 , wherein the individual light valves are arranged in arrays in the transverse direction of the scanning direction with the light valves at a given mutual distance, and that the arrays are mutually offset in the transverse direction. 
     
     
         7 . A system for illumination of a light sensitive medium according to  claim 1 , wherein said arrays are arranged such that the projection of the individual light valves in the transverse direction of the scanning direction results in a plurality of illumination points on the light sensitive medium at mutual predetermined equal distances in the transverse direction. 
     
     
         8 . A system for illumination of a light sensitive medium according to  claim 1 , wherein at least one of said arrays of light valves of the illumination unit is displaced compared to other arrays of light valves of the illumination unit 
     
     
         9 . A system for illumination of a light sensitive medium according to  claim 1 , wherein said illumination unit is produced specifically for the task the illumination system is intended 
     
     
         10 . A system for illumination of a light sensitive medium according to  claim 1 , wherein said illumination unit comprising optical means between the light valve arrangement and the light sensitive medium for collimating and/or spreading and/or focusing the light beams emitted by the spatial light modulators. 
     
     
         11 . A system for illumination of a light sensitive medium according to  claim 1 , wherein the light valves of the illumination unit are formed by reflection based spatial light modulators comprising DMD (DMD: Digital Micromirror Device) chips. 
     
     
         12 . A system for illumination of a light sensitive medium according to  claim 1 , wherein said light valves of the illumination unit are formed by spatial light modulators, such as LCD (LCD: Liquid Crystal Display), PDLC (PDLC: Polymer-dispersed Liquid Crystal), PLZT (PLZT: lead lanthanum-droped zirconate titanate), FELCD (FELCD: Ferroelectric Liquid Crystal Display) or Kerr cells. 
     
     
         13 . A system for illumination of a light sensitive medium according to  claim 1 , wherein the light valves are arranged in two or more illumination heads, each illumination head being adapted to perform a relative movement across an illumination area of the light sensitive medium. 
     
     
         14 . A system for illumination of a light sensitive medium according to  claim 1 , wherein said illumination unit comprises optical light guide or guides formed by optical fibers, preferably multimode fibers.