Holographic reconstruction system having an enlarged visibility region

Abstract

The invention relates to a holographic reconstruction system for the reconstruction of scenes having at least one video hologram modulated wave front, and an enlarged visibility region. The system utilizes two-dimensional coded light modulator cells of spatial light modulation means and optical focusing means, which realize a Fourier transformation of the modulated wave front in their focal plane. First optical deflection means deflect the parallel disposed partial light waves such that their Fourier transformations appear as cascading in the focal plane. A spatial frequency filter located on the focal plane, lets each of the same diffraction orders of all modulated partial light waves pass, and second optical deflection means arrange the wave front strips next to each other at the modulated wave front, which reconstructs the scene.

1 . Device for reading out information encoded on a light modulator device, comprising
 a light source;   the light modulator device with an encoding surface comprising m pixel rows at n pixels each;   optical deflecting means disposed in the light path to realise a horizontal offset of k modulator lines into which the encoding surface is divided, wherein each of said modulator lines comprises at least one pixel row,   optical means for generating of Fourier transforms of the horizontal modulator lines in a Fourier plane of the light modulator device.   
     
     
         2 . Device according to  claim 1 , comprising a filter which limit the Fourier transforms of the modulator lines to one selected diffraction order each. 
     
     
         3 . Device according to  claim 1 , wherein the encoding surface of the light modulator device comprises m pixel rows in the vertical direction with n pixels each in the horizontal direction, where multiple pixel rows form one modulator line in a given coordinate system. 
     
     
         4 . Device according to  claim 1 , wherein the optical deflection means is a prism array with prisms which lie in the optical light path and which have respective inclinations, said inclinations being chosen such that the corresponding angular ranges of adjacent modulator lines are adjoined such that a seamless connection of the diffraction angles of the offset k modulator lines can be achieved in the horizontal direction. 
     
     
         5 . Device according to  claim 4 , wherein the angular range of each modulator line is defined by the maximum diffraction angle of the light modulator in the horizontal direction. 
     
     
         6 . Device according to  claim 4 , wherein the optical deflection means is a prism array with micro prisms, wherein each modulator line is assigned with a multitude of micro prisms, which direct the light in a step-like manner. 
     
     
         7 . Device according to  claim 1 , wherein the optical means is an optical focusing means which has different focal planes in the horizontal and in the vertical directions. 
     
     
         8 . Device according to  claim 7 , wherein a focal plane of the optical means is provided in near of a filter, such that a Fourier transform of each modulator line appears in near of the filter in the direction of deflection of the optical deflection means, wherein a further focal plane lies such that the optical means vertically image the illuminated light modulator device onto an imaging plane, which coincides locally with the Fourier plane. 
     
     
         9 . Device according to  claim 7 , wherein the optical means have a focal length f x  in one direction, and where they are disposed at that distance f x  behind the light modulator device, wherein the optical means have the focal length f y  in the other direction, where f y =f x /2, and where the distances between the light modulator device and the optical means, and between the optical means and the filter are both 2f y . 
     
     
         10 . Device according to  claim 2 , wherein the filter is an aperture mask, the filter comprises step-like offset transparent areas, which have a shape and position that corresponds to the shape and position of the same diffraction orders in the focal plane. 
     
     
         11 . Device according to  claim 10 , wherein second optical deflection means are provided which string together the passing diffraction orders of the light of the modulator lines so to form a modulator line strip. 
     
     
         12 . Device according to  claim 11 , wherein the second optical deflection means are a prism array with prisms or micro-prisms which lie in the optical path of the filtered partial light waves, and which string together the step-like offset filtered partial light waves in one dimension so to form a modulator line strip. 
     
     
         13 . Device according to  claim 12 , wherein the angular range of the micro-prisms is adjustable, and wherein each modulator line is assigned with a multitude of micro-prisms, which are controlled by an eye finder such that the modulator line strips with their partial light waves are directed in accordance with an eye position. 
     
     
         14 . Device according to  claim 13 , wherein a tracking device controls the adjustable micro-prisms such that the partial light waves follow the movements of the eye positions of observer eyes. 
     
     
         15 . Device according to  claim 11 , wherein the second optical deflection means are prisms which are attached to the filter or wherein the second optical deflection means are an array of mirror elements which are inclined in different directions or wherein the second optical deflection means are a one-dimensional diffuser which compensates the step-like offset of the partial light waves. 
     
     
         16 . Device according to  claim 11 , wherein a controller is provided which discretely controls adjustable third optical deflection means such that the third optical deflection means position the modulator line strips side by side so to form the light which displays a scene. 
     
     
         17 . Device according to  claim 16 , wherein the adjustable third optical deflection means are discretely movable mirror means or adjustable micro-prisms. 
     
     
         18 . Device according to  claim 16 , wherein the controller is connected with a tracking device, which controls the third optical deflection means such that the partial light waves follow the movements of the eye positions of observer eyes. 
     
     
         19 . Device according to  claim 1 , wherein the light modulator device is encoded with a hologram or a computer-generated hologram which reconstructs a structure of virtual light sources. 
     
     
         20 . Device according to  claim 1 , wherein it serves in a holographic or autostereoscopic system for three-dimensional image representation as a backlight in order to realise virtual light sources for illuminating a spatial light modulator device. 
     
     
         21 . Method for reading out information encoded on a light modulator device where light illuminates a two-dimensional encoding surface of the light modulator device comprising pixels, wherein:
 Dividing/Subdividing of the encoding surface of the light modulator device into k horizontal modulator lines, where each modulator line corresponds with at least one horizontal pixel row;   Rearranging of the modulator lines arranged vertically one below another by a mutual horizontal offset;   Generating of Fourier transforms of the horizontally offset modulator lines in a Fourier plane of the light modulator.