Method and apparatus for manufacturing a security document comprising a lenticular array and blurred pixel tracks

Abstract

This invention relates to a method of manufacturing a display device, in particular a security document, comprising the steps of providing m images of an object, wherein m is at least equal to 2, dividing each image into n sets adjacent arrays ( 1 1,1 , 1 1,2 . . . 1 1,n ), . . . , ( 1 m1 , 1 m2 , . . . 1 mn ) of picture elements, spaced at a mutual distance δ, applying the images in an interlaced manner on an image layer in sets of interlaced arrays ( 1 11 , 1 21 . . . 1 m1 ), . . . , ( 11n , 1 2n . . . 1 mn ) below a lens structure comprising line-shaped lens elements over the image layer with one line shaped lens element overlying a corresponding set of adjacent arrays, characterised in that upon applying the arrays onto the image layer, and/or upon providing the lens elements, each array of picture elements is provided onto the image layer in an out of focus manner to form a blurred array or each array is imaged by the lens elements to form a blurred array, wherein a mutual distance of the edges of adjacent blurred arrays is smaller than the mutual distance δ.

1 - 13 . (canceled) 
     
     
         14 . A method of manufacturing a display device, comprising the steps of:
 (a) providing m images of an object, wherein m is at least equal to 2,   (b) dividing each image into n sets adjacent arrays ( 1   1,1 ,  1   1,2  . . .  1   1,n ), . . . , ( 1   m1 ,  1   m2 , . . .  1   mn ) of picture elements, spaced at a mutual distance δ,   (c) applying the images in an interlaced manner on an image layer in sets of interlaced arrays ( 1   11 ,  1   21  . . .  1   m1 ), . . . , ( 1   1n ,  1   2n , . . .  1   mn ) below a lens structure comprising line-shaped lens elements over the image layer with one line shaped lens element overlying a corresponding set of adjacent arrays,   wherein upon applying the arrays onto the image layer and/or upon providing the lens elements, each array of picture elements is provided onto the image layer in an out of focus manner to form a blurred array or each array is imaged by the lens elements to form a blurred array, and   wherein a mutual distance of the edges of adjacent blurred arrays is smaller than the mutual distance δ.   
     
     
         15 . The method according to  claim 14 , wherein the arrays of picture elements are provided on the image layer by projection or a scanning an optical beam onto the lens elements and focusing the beam by said lens elements onto the image layer, wherein a distance H between the image layer and the lens elements is different from the focal length of the lens elements by at least 5%, preferably at least 10%, more preferably at least 20%. 
     
     
         16 . The method according to  claim 14 , wherein the array of picture elements is provided onto the image layer in an out-of focus manner by means of printing. 
     
     
         17 . The method according to  claim 14 , wherein the edges of adjacent blurred arrays are substantially touching. 
     
     
         18 . The method according to  claim 14 , wherein the increase in width caused by applying the arrays in an out of focus manner is between 5% and 100%. 
     
     
         19 . The method according to  claim 18 , wherein the increase in width caused by applying the arrays in an out of focus manner is between 5% and 50%. 
     
     
         20 . The method according to  claim 19 , wherein the increase in width caused by applying the arrays in an out of focus manner is between 5% and 30%. 
     
     
         21 . The method according to  claim 20 , wherein the increase in width caused by applying the arrays in an out of focus manner is between 5% and 15%. 
     
     
         22 . A display device comprising an array of lens elements overlying an image layer with sets of pixel tracks produced by the method according to  claim 14 . 
     
     
         23 . An apparatus for producing a display device, comprising:
 (a) an optical beam generator,   (b) a substrate carrier for carrying an image layer having a top surface, and   (c) a scanning device for scanning an optical beam across an image layer on the substrate carrier in a line pattern,   wherein the optical beam is focussed above the top surface of the image layer or below the image layer.   
     
     
         24 . The apparatus according to  claim 23 , further comprising a tilting drive for tilting the substrate carrier around an axis extending substantially transversely to the optical beam. 
     
     
         25 . The apparatus according to  claim 23 , wherein the optical beam generator comprises a laser. 
     
     
         26 . An apparatus for producing a display device, comprising:
 (a) an optical beam generator,   (b) a substrate carrier,   (c) a scanning device for scanning an optical beam across an image layer on the substrate carrier in a line pattern, a control unit for storing a number of arrays of pixel elements of width w spaced at a mutual distance δ, and for controlling the optical beam generator and/or the scanning device for scanning the arrays onto the image layer on the substrate carrier, and   (d) a tilting drive for tilting the substrate carrier around an axis extending substantially transversely to the optical beam,   wherein the control unit is adapted to form blurred interlaced pixel arrays of an out of focus width w′ larger than width w, that can be written onto an image layer placed on the substrate carrier such that a mutual distance δ′ of the edges of adjacent blurred pixel arrays is smaller than the mutual distance δ.   
     
     
         27 . Apparatus according to  claim 26 , wherein an optical beam is projected onto the image layer surface via a lens. 
     
     
         28 . The apparatus according to  claim 26 , wherein the optical beam generator comprises a laser. 
     
     
         29 . A display device comprising an image layer and a substrate having at a distance H above the image layer a number of line-shaped lens elements, which are adapted to focus a light beam for applying arrays of picture elements onto the image layer in a focal plane situated at a distance L from the lens-elements in which L is larger or smaller than H. 
     
     
         30 . The display device according to  claim 29 , wherein H is between 100 μm and 500 μm, L being different from H by at least 10%. 
     
     
         31 . The display device according to  claim 30 , wherein H is between 100 μm and 500 μm, L being different from H by at least 20%. 
     
     
         32 . The display device according to  claim 31 , wherein H is between 100 μm and 500 μm, L being different from H by at least 30%. 
     
     
         33 . The displace device according to  claim 29 , wherein the device is a security document.