GB2476160A

GB2476160A - Flat panel 3D television and projector

Info

Publication number: GB2476160A
Application number: GB1020710A
Authority: GB
Inventors: David Brotherton-Ratcliffe
Original assignee: Geola Technologies Ltd
Current assignee: Geola Technologies Ltd
Priority date: 2009-12-07
Filing date: 2010-12-07
Publication date: 2011-06-15
Anticipated expiration: 2030-12-07
Also published as: GB201020710D0; GB0921336D0; GB2476160B

Abstract

A flat-panel TV based on a plurality of electrostatic micro-motors arranged in an ordered 2-dimensional grid (fig. 1) is disclosed. In one embodiment the motors turn vertically diffusing micro-mirrors (108,109, fig. 1) and one or more DMD projectors 601 operating at high frequency are used to illuminate an entire screen. Temporal synchronisation of the DMD signals with the motor rotation allows the creation of the angular information necessary for the horizontal parallax of a 3D moving image. In a further embodiment each of the motors is used to rotate an LED and attached optic and the LEDs are then modulated by a signal synchronised to the rotation frequency of the motors.

Description

FLAT PANEL 3D TELEVISION

BACKGROUND OF THE INVENTION

The present invention relates to the field of 3D television and 3D displays.

Current 3D TV relies on various simple techniques that can be easily engineered around conventional flat screen 2D displays. These techniques either lead to the necessity of wearing specialised glasses in order to perceive the 3D effect or to a critical constraint of the observer's head position.

It is desired to provide an improved flat panel 3D television.

SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a flat-panel 3D television comprising: a matrix of light-sources free to rotate about a first axis; a collimation device arranged to collimate the light emission from each source in one dimension; a device arranged to rotate the light-sources; a modulation device arranged to modulate the emitted light intensity of each light-source; a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each light source; and a device arranged to electronically store a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of the scene; wherein the image data is used to drive the modulation device and/or the rotation synchronisation device in order to synthesise a 3D real-time image of the scene.

The light-sources preferably comprise light-emitting diodes.

The matrix preferably comprises a rectangular matrix comprising at least n columns by m rows where n and m are selected from the group consisting of: (i) 99<n<300, 99<m<300; (ii) 300<n<1000, 300<m<1000; (iii) 1000<n<3000, 1000<m<3000; and (iv) n>3000, m>3000.

The width w and height h of the matrix is preferably selected from the group consisting of: (i) lOcm<w<3Ocm, lOcm<h<3Ocm; (ii) 3Ocm<w<200cm, 3Ocm<h<200cm; and (iii) w>200cm, h>lOOcm.

The rotation device preferably comprises an electrostatic motor or a MEMS device.

The flat-panel 3D television preferably comprises a sensor to track the position of the eyes of a first observer and wherein the sensor is used to further control the modulation device and rotation synchronisation device of each light-source such that different light intensity patterns are created at different observation points.

The flat-panel 3D television preferably comprises further sensors for second, third and further observers and wherein the further sensors are used to further control the modulation device and rotation synchronisation device of each light-source such that different light intensity patterns are created at the additional different observation points.

In use, the illusion of a full-parallax 3D real-time image for one or more observers is preferably created and/or wherein additional devices are used to create the illusion of 3D real-time images for different observers.

The light-sources preferably comprise laser diodes.

The collimation device preferably comprises holographic optical elements.

According to an aspect of the present invention there is provided a flat-panel 3D television with projector comprising: a matrix of mirrors free to rotate about a first axis; a rotation device arranged to rotate the mirrors; a device arranged to electronically store a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of the scene; a projection device arranged to project the 2D images onto the matrix of mirrors; a diffusing device arranged to diffuse reflected light from the mirrors in the first dimension; and a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each mirror; wherein the image data and the projection device are used to drive a modulation device and/or the rotation synchronisation device in order to synthesise a 3D real-time image of the scene.

The mirrors preferably comprise two-sided one-dimensionally curved or flat mirrors.

The matrix preferably comprises a rectangular matrix comprising at least n columns by m rows, wherein n and m are selected from the group consisting of: (i) 99<n<300, 99<m<300; (ii) 300<n<1000, 300<m<1000; (iii) 1000<n<3000, 1000<m<3000; and (iv) n>3000, m>3000.

The width w and height h of the matrix is preferably selected from the group consisting of: (i) lOcm<w<3Ocm, lOcm<h<3Ocm; (ii) 3Ocm<w<200cm, 3Ocm<h<200cm; (iii) w>200cm, h>lOOcm.

The flat-panel 3D television preferably comprises a sensor to track the position of the eyes of a first observer, wherein the sensor is used to further control a modulation device and/or the rotation synchronisation device such that different light intensity patterns are created at different observation points.

The flat-panel 3D television preferably comprises further sensors provided for second, third and further observers, wherein the further sensors are used to further control a modulation device and/or the rotation synchronisation device such that different light intensity patterns are created at the additional different observation points.

In use, the illusion of a full-parallax 3D real-time image for one or more observers is preferably created and/or wherein additional devices are used to create the illusion of different 3D real-time images for different observers.

The projection device preferably has a frequency of image repetition of at least 1000 Hz.

The diffusing device preferably comprises holographic optical elements.

According to an embodiment the mirrors and the diffusing device may be combined into a single holographic optical element.

The mirrors preferably comprise holographic optical elements.

According to an aspect of the present invention there is provided a method of displaying in real-time a 3D horizontal-parallax only image on a flat-panel 3D television comprising: providing a matrix of light-sources free to rotate about a first axis; collimating the light emission from each source in one dimension; rotating the light-sources; providing a modulation device arranged to modulate the emitted light intensity of each light-source; providing a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each light source; and electronically storing a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of the scene; wherein the image data is used to drive the modulation device and/or the rotation synchronisation device in order to synthesise a 3D real-time image of the scene.

According to an aspect of the present invention there is provided a method of projecting in real-time a 3D horizontal-parallax only image onto a flat-panel 3D television screen comprising: providing a matrix of mirrors free to rotate about a first axis; rotating the mirrors; providing a device arranged to electronically store a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of the scene; providing a projection device arranged to project the 2D images onto the matrix; providing a device arranged to diffuse the reflected light from the mirrors in the first dimension; and providing a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each mirror; wherein the image data and the projection device are used to drive a modulation device and/or the rotation synchronisation device in order to synthesise a 3D real-time image of the scene.

A new flat panel concept for 3D TV is disclosed that does not require a user to wear glasses and that is capable of projecting a moving horizontal parallax 3D image into a large zone in front of the display.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Fig. 1 shows a flat panel according to an embodiment of the present invention; Fig. 2 shows a reverse of the panel shown in Fig. 1; Fig. 3 shows a small section of a mirror array; Fig. 4A shows a mirror rotating within a cell, Fig. 4B shows a mirror rotating within a cell and Fig. 4C shows a mirror rotating within a cell; Fig. 5A shows a mirror rotating within a cell, Fig. 5B shows a mirror rotating within a cell and Fig. 5C shows a mirror rotating within a cell; and Fig. 6 shows a Digital Micromirror Device ("DMD") projector illuminating a mirror screen according to an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Fig. 1 shows a diagram of a preferred embodiment of the present invention. A block of plexiglass 65 mm x 65 mm x 3 mm is arranged as a substrate 101. From this substrate 101 rectangular holes 3.2 mm x 3.2 are preferably cut completely through. Within each hole a small metallic conducting mirror 3 mm x 3 mm mounted on a conducting metallic axle 108,109 is placed. The axle sits into a recessed half-cylindrical volume of the substrate 101 above and below each rectangular hole. Each recessed volume is coated with a metallic film which joins to the axle above or below. In this way all mirrors 108,109 in a column are electrically connected.

Metallic conducting strips 110,111 are laid down onto the plexiglass substrate 101 between each of the mirror-occupied holes. Connectors 102,104,103 are used to supply voltage to these conducting strips. Connectors 106,107 are used to supply voltage to the mirrors themselves.

Fig. 2 shows the reverse side of the panel as shown in Fig. 1. Metallic electrode strips 202,203 are mounted directly onto the panel. These can be charged via electrodes 204,205.

Fig. 3 shows a small section of a mirror array as described above. Individual mirrors 301,302 can be seen. Each cell has three electrodes 303,304,305 of which one 305 is shared with its neighbour. The entire display is sealed by dielectric sheets 306,307 and air is evacuated from each cell. The top sheet also serves to complete the hole in which each axle of each mirror is held forming a complete cylinder around each axle.

By connecting high voltage (preferably < 350 V) signals to each of the three electrodes surrounding a given cell its mirror can be made to rotate. This is shown in Figs. 4A-C and 5A-C where the electrodes 402,403,404 are fed alternating voltages differing in phase by 90 degrees. This creates an electrostatic force on the mirror 401 which causes it to rotate. The speed (and direction) of rotation can then be controlled accurately via the frequency of the voltage applied. The progression as shown in Figs. 4A-C and Figs. 5A-C represents the situation at each temporal advancement of 90 degrees phase.

Fig. 6 shows how a Digital Micromirror Device ("DMD") projector 601 preferably illuminates the mirror screen 602. By synchronizing the DMD video signal to the mirror rotation signal time-multiplexed angular information is created from each mirror "pixel". By incorporating a vertically diffusing layer on each of the mirrors, an observer 603 can then observe a true 3D (Horizontal Parallax Only) image.

A potential limitation is the picture repetition frequency of the DMD projector. Since time multiplexing of the projector signal is used to achieve angular information at each physical screen pixel it can be expected a reduction of several hundred times in the effective 3D picture repetition frequency. If a fast enough projector is not used then this will mean that some 3D image flicker may then be observed.

In order to avoid this problem, one or more miniature video cameras may be used to track the eyes of the observer looking at the screen and the system may be arranged so as to only project stereo pairs into his/her eyes. This allows a proper 3D image to be observed by a single person as they move around the room and at a rate that causes no flicker. In addition, a video signal only comprising stereo pairs is required.

The above technique can be extended to multiple people. However, each time a new person is "added" the effective picture repetition rate will go down. If the projector has not got a sufficiently high repletion rate then this effectively limits the number of people that can see 3D through the system.

Another technique is to use multiple projectors that illuminate the mirror screen from different horizontal angles all synchronised to the mirror rotation such that different projectors either cover different angular zones or they correspond to different viewers.

All of the mirrors preferably move synchronously and this is effected by alternating the polarity of each adjoining column of mirrors and otherwise driving the entire array with the same 3-phase voltages.

A higher voltage is preferably required at start-up to overcome friction in the mirror bearings. The high rotation speed attained preferably gives rotation rate stability via inertia.

Evacuating each cell reduces turbulence that can otherwise change the angular rotation rate and disrupt the 3D picture.

By replacing each of the micro-mirrors with a chargeable metal plate attached to a miniature LED bonded to an optic that collimates the emitted light in the horizontal direction and diffuses it vertically, a second embodiment of the invention is provided that does not require illumination by one or more projectors. Rather according to this embodiment a self-contained flat panel display is provided that emits its own 3D image.

In this embodiment two electrodes for each LED are required and one electrode feeds the metallic plate that feels the electrostatic force creating the rotation. This requires a more complex arrangement of electrodes on the surface of the plexiglass substrate such that a low-voltage current may be driven between each of the two electrodes for control of the LED but in addition a high voltage charge may be imparted to one of the electrodes.

The technology for such connections is known from conventional flat-panel displays.

By controlling the signal driving each LED and by synchronising this signal to the high voltage rotation signal, horizontal angular information may be generated for each LED pixel. Since each LED is driven independently there is no problem with picture repetition rate. However, the technique of only projecting an image into one or more observers' eyes can again be used if only a stereo-pair video signal is available.

Both of the above embodiments can be used to display different 3D or 2D TV pictures to multiple people in the same room. By incorporating facial recognition into the "eye-tracking" or "head-tracking" systems, images may also be projected only into recognised observers. Such systems have useful security applications.

The size of the mirrors and LEDs described in these embodiments can be reduced considerably before diffraction limits angular resolution. As the size reduces, so problems to do with the wear of the axles reduce as does the voltage required for rotation.

A 1 3 x 13 pixel matrix has been described for clarity and illustrative purposes only.

The technique can be scaled up using well-known techniques such as micro lithography to matrices of greater than 1000 x 1000. Sub-mm LED or mirrors enable a true 3D HDTV to be provided.

Two embodiments of a 3D TV system have been described. The preferred embodiment represents a significant improvement over conventional arrangements as it allows proper 3D real-time images to be displayed to a plurality of people at the same time without glasses and without the problem of critical head placement. It also provides a solution for a true self-illuminated flat-panel 3D HDTV. Combined with well-known eye-tracking technology the preferred embodiment allows different 2D or 3D TV programmes to be watched by many people in the same room on the same screen. Finally, eye-tracking allows the effective display of full-parallax images from computer CAD systems through real-time recalculation of stereo-pair renders at each updated eye position.

Although the present invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the accompanying claims.

Claims

Claims 1. A flat-panel 3D television comprising: a matrix of light-sources free to rotate about a first axis; a collimation device arranged to collimate the light emission from each source in one dimension; a device arranged to rotate said light-sources; a modulation device arranged to modulate the emitted light intensity of each light-source; a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each light source; and a device arranged to electronically store a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of said scene; wherein said image data is used to drive said modulation device and/or said rotation synchronisation device in order to synthesise a 3D real-time image of said scene.
2. A flat-panel 3D television in claim 1, wherein said light-sources comprise light-emitting diodes.
3. A flat-panel 3D television as claimed in claim 1 or 2, wherein said matrix comprises a rectangular matrix comprising at least n columns by m rows where n and m are selected from the group consisting of: (i) 99<n<300, 99<m<300; (ii) 300<n<1000, 300<m<1 000; (iii) 1000<n<3000, 1000<m<3000; and (iv) n>3000, m>3000.
4. A flat-panel 3D television as claimed in claim 1, 2 or 3, wherein said width w and height h of said matrix is selected from the group consisting of: (i) 1 Ocm<w<3Ocm, lOcm<h<3Ocm; (ii) 3Ocm<w<200cm, 3Ocm<h<200cm; and (iii) w>200cm, h>lOOcm.
5. A flat-panel 3D television as claimed in any preceding claim, wherein said rotation device comprises an electrostatic motor.
6. A flat-panel 3D television as claimed in any of claims 1-4, wherein said rotation device comprises a MEMS device.
7. A flat-panel 3D television as claimed in any preceding claim, further comprising a sensor to track the position of the eyes of a first observer and wherein said sensor is used to further control the modulation device and rotation synchronisation device of each light-source such that different light intensity patterns are created at different observation points.
8. A flat-panel 3D television as claimed in claim 7, further comprising further sensors for second, third and further observers and wherein said further sensors are used to further control the modulation device and/or the rotation synchronisation device of each light-source such that different light intensity patterns are created at the additional different observation points.
9. A flat-panel 3D television as claimed in claim 7 and 8, wherein, in use, the illusion of a full-parallax 3D real-time image for one or more observers is created and/or wherein additional devices are used to create the illusion of 3D real-time images for different observers.
10. A flat-panel 3D television as claimed in claim 9, wherein said light-sources comprise laser diodes.
11. A flat-panel 3D television as claimed in any preceding claim, wherein said collimation device comprise holographic optical elements.
12. A flat-panel 3D television with projector comprising: a matrix of mirrors free to rotate about a first axis; a rotation device arranged to rotate the mirrors; a device arranged to electronically store a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of said scene; a projection device arranged to project said 2D images onto said matrix of mirrors; a diffusing device arranged to diffuse reflected light from said mirrors in the first dimension; and a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each mirror; wherein said image data and said projection device are used to drive a modulation device and/or said rotation synchronisation device in order to synthesise a 3D real-time image of said scene.
13. A flat-panel 3D television as claimed in claim 12, wherein said mirrors comprise two-sided one-dimensionally curved or flat mirrors.
14. A flat-panel 3D television as claimed in claim 12 or 13, wherein said matrix comprises a rectangular matrix comprising at least n columns by m rows, wherein n and m are selected from the group consisting of: (i) 99<n<300, 99<m<300; (ii) 300<n<1000, 300<m<1 000; (iii) 1000<n<3000, 1000<m<3000; and (iv) n>3000, m>3000.
15. A flat-panel 3D television as claimed in claim 12, 13 or 14, wherein the width w and height h of said matrix is selected from the group consisting of: (i) 1 Ocm<w<3Ocm, lOcm<h<3Ocm; (ii) 3Ocm<w<200cm, 3Ocm<h<200cm; (iii) w>200cm, h>lOOcm.
16. A flat-panel 3D television as claimed in claims 12-15, wherein said rotation device comprises an electrostatic motor.
17. A flat-panel 3D television as claimed in claims 12-15, wherein said rotation device comprises a MEMS device.
18. A flat-panel 3D television as claimed in claims 12-17, further comprising a sensor to track the position of the eyes of a first observer, wherein said sensor is used to further control a modulation device and/or said rotation synchronisation device such that different light intensity patterns are created at different observation points.
19. A flat-panel 3D television as claimed in claim 18, further comprising further sensors provided for second, third and further observers, wherein said further sensors are used to further control a modulation device and/or said rotation synchronisation device such that different light intensity patterns are created at the additional different observation points.
20. A flat-panel 3D television as claimed in claim 18 or 19, wherein, in use, the illusion of a full-parallax 3D real-time image for one or more observers is created and/or wherein additional devices are used to create the illusion of different 3D real-time images for different observers.
21. A flat-panel 3D television as claimed in any of claims 12-20, wherein said projection device has a frequency of image repetition of at least 1000 Hz.
22. A flat-panel 3D television as claimed in any of claims 12-21, wherein said diffusing device comprise holographic optical elements.
23. A flat-panel 3D television as claimed in any of claims 12-22, wherein said mirrors and said diffusing device are combined into a single holographic optical element.
24. A flat-panel 3D television as claimed in any of claims 12-23, wherein said mirrors comprise holographic optical elements.
25. A method of displaying in real-time a 3D horizontal-parallax only image on a flat-panel 3D television comprising: providing a matrix of light-sources free to rotate about a first axis; collimating the light emission from each source in one dimension; rotating the light-sources; providing a modulation device arranged to modulate the emitted light intensity of each light-source; providing a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each light source; and electronically storing a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of said scene; wherein said image data is used to drive said modulation device and/or said rotation synchronisation device in order to synthesise a 3D real-time image of said scene.
26. A method of projecting in real-time a 3D horizontal-parallax only image onto a flat-panel 3D television screen comprising: providing a matrix of mirrors free to rotate about a first axis; rotating the mirrors; providing a device arranged to electronically store a time-sequence of 2D image data of a 3D scene from a number of horizontally displaced viewpoints in front of said scene; providing a projection device arranged to project said 2D images onto said matrix; providing a device arranged to diffuse the reflected light from said mirrors in the first dimension; and providing a rotation synchronisation device arranged to control and synchronise the rotation rate and/or angle of each mirror; wherein said image data and said projection device are used to drive a modulation device and/or said rotation synchronisation device in order to synthesise a 3D real-time image of said scene.