1. Field of the Invention
Directional light modulation, 3D displays, emissive micro displays, 2D/3D autostereoscopic switchable displays.
2. Prior Art
In some switchable 2D/3D displays a directional backlight is necessary to operate the display in different display modes. In a 2D display mode, a backlight with uniform illumination and large angular coverage is required to display a single image with spatial light modulators (such as liquid crystal displays (LCD)). In a 3D display mode, a backlight with uniform illumination and multiple illumination directions is required to display images of the same scene from different directions by utilizing some combination of spatial multiplexing and temporal multiplexing in the spatial light modulator.
In both 2D and 3D modes, the light that comes from the directional backlight is usually processed by a directionally selective filter (such as diffractive plate, a holographic optical plate etc.) before it reaches the spatial light modulator pixels to expand the light beam uniformly while keeping its directionality.
Currently available directional light modulators are a combination of an illumination unit comprising multiple light sources and a directional modulation unit that directs the light emitted by the light sources to a designated direction (see
In both electro-mechanically and electro-optically modulated directional light modulators there are three main problems:
1. Speed: When electrical energy is used to create mechanical movement or optical change, the movement or change is not achieved instantaneously. Usually a type of acceleration, deceleration and stabilization has to be achieved to reach the desired mechanical or optical state. The speed of these operations usually takes up a significant portion of the frame time that reduces the efficiency and limits the achievable display brightness.
2. Volumetric thickness of the device: Both of these methods need a distance between the light source and directional modulation device to work with, which increases the total thickness of a display.
3. Light loss: Coupling light on to a moving mirror assembly or using a liquid lens with adjustable focal length creates a light loss on the order of 50% to 90% which in turn requires more power consumption to compensate for the light loss, and creates heat in the system that has to be eliminated by a cooling method.
In addition to being slow, bulky and optically lossy, the prior art directional backlight units need to have narrow spectral bandwidth, high collimation and individual controllability for being combined with a directionally selective filter for 2D-3D switchable display purposes. Achieving narrow spectral bandwidth and high collimation requires device level innovations and optical light conditioning, increasing the cost and the volumetric aspects of the overall system. Achieving individual controllability requires additional circuitry and multiple light sources, increasing the system complexity, bulk and cost.
It is therefore an objective of this invention to introduce a spatio-optical light modulator that overcomes the drawbacks of the prior art, thus making it feasible to create 3D displays that provide practical volumetric and viewing experience. Additional objectives and advantages of this invention will become apparent from the following detailed description of a preferred embodiment thereof that proceeds with reference to the accompanying drawings.
The invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements.
References in the following detailed description of the present invention to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristics described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in this detailed description are not necessarily all referring to the same embodiment.
A new class of emissive display devices called Quantum Photonic Imagers (QPI™, a trademark of Ostendo Technologies, Inc.) has been recently introduced (see U.S. Pat. Nos. 7,623,560, 7,767,479, 7,829,902 and 8,049,231 and U.S. Patent Application Publication Nos. 2009/0086170, 2009/0278998, 2010/0003777, 2010/0066921, 2010/0091050 and 2010/0220042). The QPI devices feature high brightness, very fast light amplitude modulation and spatial modulation capabilities in a very small device volume that includes all the driver circuitry.
The present invention combines the emissive micro array capabilities of the QPI device with passive wafer level optics (WLO) to create a light modulator that can perform the functionalities of a directional light source and a diffractive plate at the same time. As used herein, wafer level or wafer means a device or matrix of devices having a diameter of at least 2 inches, and more preferably 5 inches or more. WLO are fabricated monolithically on the wafer from polymer using ultra violet (UV) imprint lithography. Among primary advantages of WLO are the ability to fabricate micro lens arrays and to be able to precisely align multiple WLO optical elements together and with an optoelectronics device such as a CMOS sensor or the QPI device. The alignment precision that can be achieved by a typical WLO fabrication technique can be less than one micron. The combination of the digitally addressable emissive micro emitter pixel array of the QPI device and the WLO micro lens array (MLA) that can be precisely aligned with respect to the micro emitter array of the QPI device eliminates the need for having a directionally selective filter in the system while relaxing the requirement for the narrow spectral bandwidth in the light source, reducing the system volume, complexity and cost simultaneously.
With a fine pitch wafer level collimating MLA, the light emitted from the QPI device micro emitter array of pixels can be modulated directionally as illustrated in
It is obvious to a person skilled in the art that the directional modulation by a lens can be done on a single axis, or on two axes with the choice of lens type (i.e., lenticular lens array or two-axis lens array). However, precise alignment of the lens array with the pixelated light source and the achievability of small pixel size (in the order of few microns, or 10 microns or less) have prevented the realization of a directional light modulator that can generate the directional light modulation capabilities needed to create high definition 3D displays. In the present invention the high pixel resolution is achieved by leveraging the emissive micro pixel array of the QPI device, which can attain less than 10 micron pixel pitch, and the high precision alignment of lens array, which can be less than one micron, made possible by the wafer level optics. This allows the spatio-optical light modulator of this invention to achieve the spatial as well as directional modulation resolution sufficient to realize a high definition 3D displays.
Referring to
Any desired spatial and directional modulation capabilities for the QPI device based spatio-optical directional light modulator of this invention would be possible using an array of (N×M) of the directional modulation groups Gi such as that described in the previous design example. If, for example, it is required to create a spatio-optical directional light modulator with spatial modulation resolution of N=320 by M=240 that provides (256)2=65,536 directional modulation resolution, the spatio-optical directional light modulator of this invention would comprise an array of (320×240) directional modulation groups and when a QPI device with (5×5) micron pixel size is used, the total size of the spatio-optical directional light modulator would be approximately 41×31 cm. The light emitted from such a spatio-optical directional light modulator can be spatially modulated at a resolution of (320×240) and directionally modulated at a resolution of 65,536 within the angular divergence ±Θ associated with its WLO micro lens array (for example Θ=±15° for the exemplary embodiment 600) and can also be modulated in color and intensity in each direction.
The resolution of the directional modulation of the light modulators of this invention in terms of the number of individually addressable directions within the angular divergence ±Θ of the wafer level micro lens array would be determined by selecting either the pixel pitch of the emissive micro emitter array QPI device or by selecting lens pitch of the wafer level micro lens array, or a combination of the two. It is obvious to a person skilled in the art that the lens system, such as that illustrated in
Depending of the total pixel resolution of the QPI device used, such a spatio-optical directional light modulator can be implemented using a tiled array comprising a multiplicity of QPI devices. For example if a QPI device with (1024×1024) pixel resolution is used, then each such QPI device can be used to implement an array of (2×2) modulation groups Gi and the spatio-optical directional light modulator having (6×6) spatial light modulation resolution and 65,536 directional light modulation resolution would be implemented using a tiled array (3×3) of such QPI devices such as in the illustration of
The tiling of an array of QPI devices to implement the spatio-optical directional light modulator of this invention is made possible because of the compactness that can be achieved by the emissive QPI devices and the associated WLO. For example, with an implementation such as that illustrated in
The principle of operation of the spatio-optical directional light modulator of this invention will be described in reference to the illustrations of
Where the angles (θ, φ) are spherical coordinates with the polar axis at θ=0 parallel to the z axis of the emissive surface of the modulation group Gi and m=log2 n is the number of bits used to express the x and y pixel resolution of the modulation group Gi.
The spatial resolution of the spatio-optical directional light modulator of this invention is simply defined by the coordinates of each of the individual modulation group Gi within the two dimensional array of modulation groups comprising the overall spatio-optical directional light modulator. There is of course, some cross talk between pixels of one group and the micro lens for an adjacent group. However the cross talk is substantially reduced by the following design aspects. First, because of the inherently collimated light emission of the QPI device, the light emitted from the QPI device pixels is typically confined to a ±17° cone for the case when the QPI device pixels are light emitting diode or to a ±5° cone for the case when the QPI device pixels are laser diodes. Thus placing the wafer level optics (WLO) collimation lens elements close to the emissive surface 660 of the QPI device as illustrated in
In using the directional modulation resolution of 16-bit of the previously described example and the typical 24-bit of resolution for representing the modulated light intensity and color in each direction, the total number bits that would represent the modulation data word for each modulation group would be 40-bit. In assuming, without loss of generality, that such 40-bit words would be inputted to the spatio-optical directional light modulator of this invention for addressing its constituent modulation groups sequentially; i.e., sequential addressing is used to input the modulation group data 40-bit words. Block 120 of
Possible Applications
The spatio-optical directional light modulator of this invention can be used as a backlight for liquid crystal display (LCD) to implement a 3D display. The spatio-optical directional light modulator of this invention by itself can be used to implement a 3D display of an arbitrary size that is realized, for example, as a tiled array of multiplicity of QPI devices/WLO assemblies such as that illustrated in
Thus the present invention has a number of aspects, which aspects may be practiced alone or in various combinations or sub-combinations, as desired. While certain preferred embodiments of the present invention have been disclosed and described herein for purposes of illustration and not for purposes of limitation, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the full breadth of the following claims.
This application claims the benefit of U.S. Provisional Patent Application No. 61/567,520 filed Dec. 6, 2011.
Number | Name | Date | Kind |
---|---|---|---|
5059008 | Flood et al. | Oct 1991 | A |
5691836 | Clark | Nov 1997 | A |
5986811 | Wohlstadter | Nov 1999 | A |
6137535 | Meyers | Oct 2000 | A |
6151167 | Melville | Nov 2000 | A |
6433907 | Lippert et al. | Aug 2002 | B1 |
6795221 | Urey | Sep 2004 | B1 |
6795241 | Holzbach | Sep 2004 | B1 |
6803561 | Dunfield | Oct 2004 | B2 |
6924476 | Wine et al. | Aug 2005 | B2 |
6937221 | Lippert et al. | Aug 2005 | B2 |
6999238 | Glebov et al. | Feb 2006 | B2 |
7009652 | Tanida et al. | Mar 2006 | B1 |
7061450 | Bright et al. | Jun 2006 | B2 |
7071594 | Yan et al. | Jul 2006 | B1 |
7106519 | Aizenberg et al. | Sep 2006 | B2 |
7190329 | Lewis et al. | Mar 2007 | B2 |
7193758 | Wiklof et al. | Mar 2007 | B2 |
7209271 | Lewis et al. | Apr 2007 | B2 |
7215475 | Woodgate et al. | May 2007 | B2 |
7232071 | Lewis et al. | Jun 2007 | B2 |
7286143 | Kang et al. | Oct 2007 | B2 |
7292257 | Kang et al. | Nov 2007 | B2 |
7324687 | Zitnick, III et al. | Jan 2008 | B2 |
7369321 | Ren et al. | May 2008 | B1 |
7379583 | Zitnick, III et al. | May 2008 | B2 |
7400439 | Holman | Jul 2008 | B2 |
7482730 | Davis et al. | Jan 2009 | B2 |
7486255 | Brown et al. | Feb 2009 | B2 |
7561620 | Winder et al. | Jul 2009 | B2 |
7580007 | Brown et al. | Aug 2009 | B2 |
7609906 | Matusik et al. | Oct 2009 | B2 |
7619807 | Baek et al. | Nov 2009 | B2 |
7620309 | Georgiev | Nov 2009 | B2 |
7623560 | El-Ghoroury et al. | Nov 2009 | B2 |
7630118 | Onvlee | Dec 2009 | B2 |
7639293 | Narabu | Dec 2009 | B2 |
7656428 | Trutna, Jr. | Feb 2010 | B2 |
7671893 | Li et al. | Mar 2010 | B2 |
7702016 | Winder et al. | Apr 2010 | B2 |
7703924 | Nayar | Apr 2010 | B2 |
7724210 | Sprague et al. | May 2010 | B2 |
7732744 | Utagawa | Jun 2010 | B2 |
7767479 | El-Ghoroury et al. | Aug 2010 | B2 |
7780364 | Raskar et al. | Aug 2010 | B2 |
7791810 | Powell | Sep 2010 | B2 |
7792423 | Raskar et al. | Sep 2010 | B2 |
7829902 | El-Ghoroury et al. | Nov 2010 | B2 |
7841726 | Conner | Nov 2010 | B2 |
7872796 | Georgiev | Jan 2011 | B2 |
7880794 | Yamagata et al. | Feb 2011 | B2 |
7897910 | Roichman et al. | Mar 2011 | B2 |
7916934 | Vetro et al. | Mar 2011 | B2 |
7936392 | Ng et al. | May 2011 | B2 |
7949252 | Georgiev | May 2011 | B1 |
7952809 | Takai | May 2011 | B2 |
7956924 | Georgiev | Jun 2011 | B2 |
7962033 | Georgiev | Jun 2011 | B2 |
7965936 | Raskar et al. | Jun 2011 | B2 |
8009358 | Zalevsky et al. | Aug 2011 | B2 |
8019215 | Georgiev et al. | Sep 2011 | B2 |
8049231 | El-Ghoroury et al. | Nov 2011 | B2 |
8106994 | Ichimura | Jan 2012 | B2 |
8126323 | Georgiev et al. | Feb 2012 | B2 |
20060098285 | Woodgate et al. | May 2006 | A1 |
20060221209 | McGuire et al. | Oct 2006 | A1 |
20070109813 | Copeland et al. | May 2007 | A1 |
20080117491 | Robinson | May 2008 | A1 |
20090086170 | El-Ghoroury et al. | Apr 2009 | A1 |
20090278998 | El-Ghoroury et al. | Nov 2009 | A1 |
20100003777 | El-Ghoroury et al. | Jan 2010 | A1 |
20100026852 | Ng et al. | Feb 2010 | A1 |
20100026960 | Sprague | Feb 2010 | A1 |
20100066921 | El-Ghoroury et al. | Mar 2010 | A1 |
20100085468 | Park et al. | Apr 2010 | A1 |
20100091050 | El-Ghoroury et al. | Apr 2010 | A1 |
20100220042 | El-Ghoroury et al. | Sep 2010 | A1 |
20100245957 | Hudman et al. | Sep 2010 | A1 |
20100265386 | Raskar et al. | Oct 2010 | A1 |
20110096156 | Kim et al. | Apr 2011 | A1 |
Number | Date | Country |
---|---|---|
2190019 | May 2010 | EP |
2398235 | Dec 2011 | EP |
2008-304572 | Dec 2008 | JP |
2010-117398 | May 2010 | JP |
WO-2005048599 | May 2005 | WO |
WO-2007092545 | Aug 2007 | WO |
WO-2011065738 | Jun 2011 | WO |
Entry |
---|
“International Search Report and Written Opinion of the International Searching Authority Dated Mar. 19, 2013, International Application No. PCT/US2012/068029”, (Mar. 19, 2013). |
Adelson, Edward H., et al., “Single Lens Stero with a Plenoptic Camera”, IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 14, No. 2, (Feb. 1992), pp. 99-106. |
Bolles, Robert C., et al., “Epipolar-Plane Image Analysis: An Approach to Determining Structure from Motion”, International Journal of Computer Vision, vol. 1, (1987), p. 7-55, February. |
Georgiev, Todor, et al., “Light Field Camera Design for Integral View Photography”, Adobe Technical Report, (2003), pp. 1-13, January. |
Nayar, Shree K., “Computational Cameras: Approaches, Benefits and Limits”, Columbia University Technical Report No. CUCS-001-11, (Jan. 15, 2011), pp. 1-22. |
Ng, Ren, “Digital Light Field Photography”, Stanford University Doctorial Thesis, (Jul. 2006), 203 pp. total. |
Ng, Ren, et al., “Light Field Photography with a Hand-held Plenoptic Camera”, Stanford University Tech Report CTSR 2005-02, (2005), pp. 1-11, July. |
Veeraraghavan, Ashok, et al., “Dappled Photography: Mask Enhanced Cameras for Heterodyned Light Fields and Coded Aperture Refocusing”, Mitsubishi Electric Research Laboratories (MERL) TR2007-115; ACM Transactions on Graphics, vol. 26, No. 3, Article 69, (Jul. 2007), pp. 69-1-69-12, 14 pp. total. |
“Invitation to Pay Additional Fees, Partial Search Report Dated Jan. 25, 2013, International Application No. PCT/US2012/068028”, (Jan. 25, 2013). |
“International Search Report and Written Opinion of the International Searching Authority Dated Sep. 18, 2013; International Application No. PCT/U52012/068028”, (Sep. 18, 2013). |
“Office Action Dated Nov. 22, 2013; U.S. Appl. No. 13/546,858”, (Nov. 22, 2013). |
“Office Action Dated Sep. 26, 2013; U.S. Appl. No. 13/546,858”, (Sep. 26, 2013). |
“Notice of Allowance Dated May 30, 2014; U.S. Appl. No. 13/546,858”, (May 30, 2014). |
Number | Date | Country | |
---|---|---|---|
20130141895 A1 | Jun 2013 | US |
Number | Date | Country | |
---|---|---|---|
61567520 | Dec 2011 | US |