# US 2008/0304014 A1 · Rear Projector and Rear Projecting Method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0304014 A1 - Document ID: US20080304014A1 - Status: Published application - Kind: A1 - Application number: 12/158,702 - Filed: 2006-12-20 - Published: 2008-12-11 - Earliest claimed: 2005-12-23 - Assignees: Koninklijke Philips Electronics N.V. - Inventors: Adrianus Johannes Stephanus Maria De Vaan - Web page: https://patentgrep.com/patent/US20080304014A1 ## CPC - G03B 35/20: using two or more projectors - G02B 30/25: using polarisation techniques - G02B 30/50: the image being built up from image elements distributed over a three-dimensional [3D] volume, e.g. voxels - H04N 9/3129: {scanning a light beam on the display screen (scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161)} - H04N 13/305: using lenticular lenses, e.g. arrangements of cylindrical lenses - H04N 13/359: Switching between monoscopic and stereoscopic modes - H04N 13/363: using image projection screens (volumetric display H04N13/388) - H04N 13/39: the picture elements emitting light at places where a pair of light beams intersect in a transparent material - H04N 13/398: Synchronisation thereof; Control thereof - H04N 13/32: using arrays of controllable light sources; using moving apertures or moving light sources - H04N 13/324: Colour aspects - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The application relates to a rear projector and a rear projection method. There is provided at least one projection screen, at least two beamers, each of the at least two beamers generating one view of a scene into at least one viewing direction and projecting the view onto the rear side of the projection screen, at least one switcheable diffuser which is switcheable between a transparent state and a diffuse state, wherein in the transparent state each beamer generates a different view of a scene, and wherein in the diffuse state the beamers generate one view of a scene. ## Claims ### Claim 1 Rear projector comprising: at least one projection screen, at least two beamers, each of the at least two beamers generating one view of a scene into at least one viewing direction and projecting the view onto the rear side of the projection screen, at least one switcheable diffuser which is switcheable between a transparent state and a diffuse state, wherein in the transparent state each beamer generates a different view of a scene, and wherein in the diffuse state the beamers generate one view of a scene. ### Claim 2 (depends on 1) Rear projector of claim 1, wherein the at least two beamers are scanning laser beamers, each of the at least two beamers generating one view of a scene into at least one viewing direction and projecting the view onto the rear side of the projection screen by scanning the projection screen with its light beam; and further comprising at least one control device (3); wherein the control device is arranged to control the scanning laser beamers such that the light beams generated from the beamers are out of phase. ### Claim 3 (depends on 2) The rear projector of claim 2, wherein the control device is arranged to control the beamers such that the light beams generated from the beamers hit the projection screen at different positions at a certain time. ### Claim 4 (depends on 1) The rear projector of claim 1, wherein the switcheable diffuser comprises a polarizing dependent diffuser which is transparent for a first polarizing direction and which is diffuse for a second polarizing direction and further at least one polarizing element for polarizing the beams of light projected onto the diffuser which is switcheable between a first polarizing direction and a second polarizing direction, ### Claim 5 (depends on 1) The rear projector of claim 1, wherein the projection screen comprises at least one of a lenticular screen; a Fresnel lens. ### Claim 6 (depends on 1) The rear projector of claim 1, wherein each beamer has a maximum luminous flux of 100 lumen, preferable less than 40 lumen. ### Claim 7 (depends on 1) The rear projector of claim 1, wherein at least 9 beamers are arranged behind the projection screen such that at least 9 different views of a scene are generated. ### Claim 8 (depends on 1) The rear projector of claim 1, wherein the beamers contain a microdisplay and an LED light source. ### Claim 9 (depends on 1) The rear projector of claim 1, further comprising at least one sensor arranged at the outer edge of the projection screen and arranged to sense at least one of the values: the phase of light beams generated from the beamers; the luminous flux of light beams generated from the beamers; the color coordinates of light beams generated from the beamers; ### Claim 10 (depends on 9) The rear projector of claim 9, further comprising coupling at least one sensor with the control device to control the light emitted from the beamers depending on the sensed values. ### Claim 11 A rear projecting method for creating at least one view of a scene, comprising: projecting at least one view of a scene into at least one viewing direction onto a rear side of a projection screen with at least two light beams; and switching at least one switcheable diffuser between a transparent state and a diffuse state, wherein in the transparent state different view of a scene are generated, and wherein in the diffuse state one view of a scene is generated. ### Claim 12 (depends on 11) The method of claim 11, further comprising generating one view of a scene into at least one viewing direction and projecting the view onto the rear side of the projection screen by scanning the projection screen with scanning laser light beams and controlling the light beams such that the light beams are out of phase. ### Claim 13 (depends on 12) The method of claim 12, further comprising controlling the light beams such that the light beams hit the projection screen at different positions at a certain time.