# US 5,703,717 A · Three-dimensional projection display apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,717 A - Document ID: US5703717A - Status: Granted - Kind: A - Application number: 08/337,932 - Filed: 1994-11-10 - Granted: 1997-12-30 - Earliest claimed: 1993-11-12 - Assignees: Sharp Kabushiki Kaisha - Inventors: David Ezra; Graham John Woodgate; Jonathan Harrold; Basil Arthur Omar - Web page: https://patentgrep.com/patent/US5703717A ## CPC - G02B 30/27: involving lenticular arrays - H04N 13/305: using lenticular lenses, e.g. arrangements of cylindrical lenses - H04N 13/31: using parallax barriers - H04N 13/32: using arrays of controllable light sources; using moving apertures or moving light sources - H04N 13/346: using prisms or semi-transparent mirrors - H04N 13/363: using image projection screens (volumetric display H04N13/388) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A 3D projection display comprises an autostereoscopic image producing unit which directs light beams corresponding to respective 2D views in different directions towards a projection lens. The projection lens co-operates with the image producing unit to image the light beams at respective different regions in the aperture of the projection lens. A light-transmissive screen co-operates with the image producing unit and the projection lens to image the views at the screen. The screen may comprise a Fresnel lens, or where a magnified image of increased angular spread is required, a double lenticular screen angular amplifier. ## Claims ### Claim 1 A three-dimensional projection display apparatus, comprising autostereoscopic image producing means for directing light beams corresponding to respective views in different directions, further comprising at least one projection lens co-operating with the autostereoscopic image producing means to image the light beams at respective different regions in the aperture of the projection lens, and a light-transmissive or light-reflective screen co-operating with the autostereoscopic image producing means and the projection lens to image the views at the screen. ### Claim 2 (depends on 1) An apparatus as claimed in claim 1, wherein the screen comprises a converging lens. ### Claim 3 (depends on 2) An apparatus as claimed in claim 2, wherein the converging lens is a Fresnel lens. ### Claim 4 (depends on 1) An apparatus as claimed in claim 1, wherein the screen comprises: a diffuser; a first array of converging lenses disposed on a first side of the diffuser for receiving light from the at least one projection lens; and a second array of converging lenses disposed on a second side of the diffuser, the converging lenses of the second array having a focal length less than that of the converging lenses of the first array. ### Claim 5 (depends on 1) An apparatus as claimed in claim 1, wherein the screen comprises: a first array of converging lenses for receiving light from the at least one projection lens; a second array of diverging lenses having a focal length less than that of the converging lenses of the first array; and a field correction element. ### Claim 6 (depends on 4) An apparatus as claimed in claim 4, wherein each of the first and second arrays comprises a lenticular screen comprising cylindrical lenticules. ### Claim 7 (depends on 5) An apparatus as claimed in claim 5, wherein each of the first and second arrays comprises a lenticular screen comprising cylindrical lenticules. ### Claim 8 (depends on 4) An apparatus as claimed in claim 4, wherein a field lens is disposed between the projection lens and the first array. ### Claim 9 (depends on 8) An apparatus as claimed in claim 8, wherein the field lens is a Fresnel lens. ### Claim 10 (depends on 1) An apparatus as claimed in claim 1, wherein the screen comprises a direction-preserving lenticular screen having a rear diffusing surface. ### Claim 11 (depends on 1) An apparatus as claimed in claim 1, wherein the autostereoscopic image producing means comprises at least one spatial light modulator and a plurality of light sources arranged such that the light sources are imaged at the respective different regions in the aperture of the projection lens and the at least one spatial light modulator is imaged at the screen. ### Claim 12 (depends on 11) An apparatus as claimed in claim 11, in which the autostereoscopic image producing means comprises a beam combiner co-operating with first and second display means. ### Claim 13 (depends on 12) An apparatus as claimed in claim 12, wherein the at least one projection lens comprises first and second projection lenses disposed between the beam combiner and the first and second display means, respectively. ### Claim 14 (depends on 12) An apparatus as claimed in claim 12, wherein each of the first and second display means comprises a spatial light modulator and at least one light source. ### Claim 15 (depends on 13) An apparatus as claimed in claim 13, wherein each of the first and second display means comprises a spatial light modulator and at least one light source. ### Claim 16 (depends on 11) An apparatus as claimed in claim 11, wherein the at least one spatial light modulator is arranged to display temporally multiplexed 2D views and the plurality of light sources are arranged to illuminate the at least one respective spatial light modulator in respective different directions corresponding to the 2D views. ### Claim 17 (depends on 11) An apparatus as claimed in claim 11, wherein the at least one spatial light modulator is arranged to display spatially multiplexed 2D views and co-operates with a respective parallax screen. ### Claim 18 (depends on 17) An apparatus as claimed in claim 17, wherein the parallax screen comprises a lenticular screen. ### Claim 19 (depends on 11) An apparatus as claimed in claim 11, wherein the at least one spatial light modulator is disposed between an input lenticular screen and an output lenticular screen whose pitch is greater than that of the input lenticular screen. ### Claim 20 (depends on 1) An apparatus as claimed in claim 1, wherein the autostereoscopic image producing means comprises a substrate carrying a spatially multiplexed image of the views and a lenticular screen. ### Claim 21 (depends on 20) An apparatus as claimed in claim 20, in which the lenticular screen is the substrate.