Patent ID: 6211977
Filing Date: 2001-04-03
Classification: G02B,G03B

Abstract:
A method of producing a holographic screen for displaying a stereoscopic or multiview color image, comprising the steps of:placing a photoplate on an x-y plane of a three dimensional space, wherein the center of the photoplate being disposed in the origin of a three-dimensional space;splitting the laser beam into two beams: reference beam and object beam, both beams being used to illuminate the photoplate surface;shaping the reference beam as a spherical wave diverging from a point on a z-axis which is located a distance R.sub.1 from the photoplate center;shaping the object beam so as to illuminate the photoplate through an elongated narrow slit-shaped diffuser inclined to the photoplate surface;recording an interference pattern, which is arising as a result of the superposition of the reference wave with an object wave from the diffuser on the photoplate;whereby the stereoscopic or multiview three dimensional color images can be displayed on a recorded screen by projectors disposed at a distance R.sub.3 from the screen, if a viewer's eyes are placed at viewing zones which are located behind the screen at a distance R.sub.4, the viewing zones being composed of superposed diffuser's real images of the different colors;wherein the coordinates of the diffuser point, which is responsible for the contribution of a light with a wavelength .lambda..sub.2 in the viewing zone, are calculated from the following equations:k.sub.2 r.sub.3 +k.sub.1 (r.sub.1 -r.sub.2)=-k.sub.2 r.sub.4 +const (1)##EQU6##where r.sub.1 is the distance between an arbitrary point (x,y) on the photoplate and a position of the source of the reference beam; r.sub.2 and R.sub.2 are the distances between a point (x,y) on the photoplate and a point on the diffuser and between the coordinate origin and the same diffuser point; .alpha. is the angle between R.sub.2 straight line and the positive z-axis; r.sub.3 is the distance between a point (x,y) on the photoplate and a point source of the projection beam; r.sub.4 is the distance between a point (x,y) on the photoplate and a viewing zone; R.sub.4 is the distance between an origin and a viewing zone; .beta. is the angle between R.sub.4 straight line and the negative z-axis; .lambda..sub.1 and .lambda..sub.2 represent wavelengths of the recording and projecting waves, respectively; k.sub.1 and k.sub.2 are wave numbers of the recording and projecting waves, respectively;wherein the diffuser's length and position are calculated using equations (2) and (3) for covering an entire spectral range of a projected image.