Light filtering arrangement for holographic displays
AssigneePolaroid Corporation
InventorStephen A. Benton
Life of this patent
Estimating the term…
Abstract
A holographic arrangement is provided with light filtering means for transmitting only those light rays to the hologram which are incident to the hologram at the prescribed angles required for substantial diffraction while at the same time operating to preclude the transmission of other light rays to the hologram which would otherwise be incident to the hologram at angles outside the prescribed range of angles required for substantial diffraction by the hologram. In this manner background light which would otherwise be transmitted through a hologram so as to degrade the quality of a stereoscopic image reconstructed from the hologram is precluded from ever reaching the viewing area.
Claims13
Apparatus responsive to the light rays emanating from a light source for displaying images by the technique of wavefront reconstruction comprising:
- a hologram;
- and
- light filtering means directly adjacent said hologram and intermediate said hologram and light source for transmitting without substantial attenuation only light rays therethrough which are incident thereon at predetermined angles in order that the transmitted light rays be incident to said hologram only at angles within the range of angles required for substantial diffraction while at the same time substantially precluding the transmission therethrough of other light rays incident thereon at angles other than said predetermined angles of incidence, in this manner substantially blocking out such extraneous background light as may be attributable to the other light rays, wherein said light filtering means includes a plurality of spaced apart louvers angled to receive and transmit the light rays incident thereon at said predetermined angles while at the same time substantially precluding the transmission of other light rays incident thereon at angles other than said predetermined angles.
Apparatus responsive to the light rays emanating from a light source for displaying images by the technique of wavefront reconstruction comprising:
- a cylindircal hologram suitable for reconstructing a stereoscopic image which may be viewed from around the entire hologram;
- and
- light filtering means substantially concentric with respect to said hologram for permitting viewing of the stereoscopic image reconstructed by the hologram from light rays diffracted by the hologram while at the same time substantially prohibiting other light rays which may impinge upon the outside of said cylindrical hologram from being transmitted through said cylindrical hologram to a viewing area outside of said cylindrical hologram.
Dependencies are inferred from the claim text.