SEAMLESS DISPLAY PANEL TILING USING AN OPTICAL EXPANSION LAYER
A display panel for use with a multi-panel display. The display panel includes a display panel including an array of display pixels disposed surrounded by a bezel, the array of display pixels for emitting a display image having a first size, and an optical expansion layer disposed over the array of display pixels to magnify the display image to appear to have a second size larger than the first size and to at least partially conceal the bezel surrounding the housing. The optical expansion layer includes a first array of microlenses optically coupled to the array of display pixels to cause light from the display pixels to diverge, a second array of microlenses having complementary optical power to the first array of microlenses; and an optically transparent offset layer disposed between the first and second arrays of microlenses. Other embodiments are disclosed and claimed.
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This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/636,458, filed 20 Apr. 2012 and still pending. The priority provisional application is hereby incorporated by reference in its entirety.
TECHNICAL FIELDThe present invention relates generally to displays and in particular, but not exclusively, to seamless display panel tiling using an optical expansion layer.
BACKGROUNDLarge wall displays can be prohibitively expensive because the cost to manufacture display panels increases exponentially with display area. This cost increase arises from the increased complexity of large monolithic displays, the decreased yields associated with large displays (a greater number of components must be defect free for large displays), and increased shipping, delivery, and setup costs. Tiling smaller display panels to form larger multi-panel displays can help reduce many of the costs associated with large monolithic displays.
Various other approaches for obtaining seamless displays include display lensing, blended projection, stackable display cubes, and LED tiles. Display lensing places a single contiguous lens in front of each display panel 100 to present a fused, borderless image in a particular “sweet spot.” However, the viewing angle is relative narrow and image distortion along continuous lines still occurs. Blended projection uses software stitching and mechanical mounting of traditional projection screens. Currently, blended projection uses relatively low cost hardware and is a good option for non-planar surfaces. However, there are significant physical constraints on usage and installation and requires regular maintenance and sophisticated calibration. Stackable display cubes are a rear projection technology. Each display cube is relatively deep and the seams between adjacent cubes are easily visible. LED tiles are arrays of discrete RGB light emitting diodes (“LED”). LED tiles can have virtually invisible seams because the seams run between pixels. However, LED tiles are expensive and have large pixel pitches (e.g., 2 to 4 mm) that result in low resolution images.
Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Embodiments are described of an apparatus, system, and method for seamless display panel tiling using an optical expansion layer. Numerous specific details are described to provide a thorough understanding of embodiments of the invention, but one skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In some instances, well-known structures, materials, or operations are not shown or described in detail but are nonetheless encompassed within the scope of the invention.
Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one described embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in this specification do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
In the illustrated embodiment, optical expansion layer 215 has a lateral dimension W2 substantially equal to the sum of dimension W1 and the width of bezel 210. Optical expansion layer 215 includes an offset layer 230 of thickness d. A first array of microlenses 220 is formed in or on one surface of offset layer 230, and a second array of complementary microlenses 225 is formed in or on the opposite surface of offset layer 230 spaced apart from each other by substantially distance d, such that individual microlenses in each array have a corresponding microlens in the other array positioned along coincident optical axis 237. In the embodiment shown, microlenses 220 and 225 are illustrated as refractive lenses, but in other embodiments other elements having optical power can be used, for example diffractive or reflective optical elements. Offset layer thickness d can depend on a variety of factors including, for example, the focal lengths of the individual microlenses in the first array of microlenses 220 and the second array of microlenses 225.
In the illustrated embodiment, when optical expansion layer 215 is positioned on display 203 the first array of microlenses 220 matches the array of display pixels 235 on a one-to-one basis; that is, each display pixel 235 is paired with a corresponding individual microlens 220. Each individual microlens 220 then magnifies the output from its corresponding display pixel 235. In magnifying the output from its corresponding pixel 235, each individual microlens 220 causes light from the pixel to diverge. Magnifying the pixel images using microlenses 220 and 225 serves to virtually displace the overall display image back to a virtual image plane 220 behind the actual image source plane 245, the result of which is that the bezel 210 is obscured.
Microlenses 225 are complementary to microlenses 220, meaning that their optical power is matched to the optical power of microlenses 220 to obtain the desired overall magnification and field of view for the user. In the illustrated embodiment, microlenses 225 further magnify the images from microlenses 220. Magnification by microlenses 225 further expands the display image to have a greater actual and/or apparent lateral extent W3 at the top surface of optical expansion layer 215 than the lateral extent W1 of pixel region 205. As such, the expanded image conceals bezel 210. In this manner, when multiple display panels 200 are tiled into a tiled multi-panel display 300 (see., e.g.,
In the illustrated embodiment, both display 203 and the optical expansion layer 215 are planar and rigid, but in other embodiments both the display panel and the optical expansion layer need not be planar or rigid, but can instead be curved and/or flexible. For example, in one embodiment display panel 203 and expansion layer 215 could both be both flexible and curved, so that a plurality of display panels 200 can be tiled onto a curved surface. In another embodiment, both display 203 and optical expansion layer 215 can be rigid and curved and can also be tiled to form a curved display.
The illustrated embodiment of control device 705 includes a camera 710, an image engine 715, and registration logic 720. In one embodiment, control device 705 can be implemented with a smart phone having a general purpose processor, a built-in camera, and wireless interface electronics (e.g., WiFi or Bluetooth transceivers). The wireless interface electronics can be used to stream the composite image to display panels 700. Operation of control device 705 to set up and configure multi-panel displays 701 or 702 is discussed in further detail in connection with
When coupling two or more display panels 700 together, perfect physical alignment cannot be achieved, or the display panel can include intentionally randomized pixels that do not perfectly align. Process 900 identifies misalignments or image discontinuities along the seams of a tiled multi-panel display (or within an interior region of the display panel) and remaps display pixel to image pixel assignments to cure the defects.
In a process block 905, two or more display panels 700 are coupled together to form a tiled multi-panel display 701. As previously stated, this coupling can result in one or more image discontinuities along the inter-panel seams. To cure these defects, image engine 715 generates an initial registration image i (e.g., i=1) for transmission to display panels 700. In one embodiment, registration image is an alternating high contrast image (e.g., black and white checkerboard image) that provides several identifiable marks along the seam edges of each display panel 700 or displays a full screen image that provides enough information to recover the full position and orientation of each panel relative to one another.
In a process block 915, camera 710 is used to capture registration image i output from multi-panel display 701. The captured registration image i is then analyzed by registration logic 720 to identify any misalignment between panels (process block 920). If the misalignment is determined to be unacceptable (decision block 925), then registration logic 720 adjusts the display pixel to image pixel mapping in an attempt to cure the discontinuities or at least reduce the number of image discontinuities. With the pixel assignments remapped, process 900 loops back to process block 910 and can iterate by redisplaying a revised registration image i. The registration iterations can continue until the alignment is determined to be within acceptable limits (decision block 925), at which time multi-panel display 701 is ready for use. Alternatively, this software alignment can be computed from a single calibration image. The remapped display pixel to image pixel assignments are maintained and used for all image feeds until the next recalibration cycle.
In some embodiments, the image registration technique described for
The processes explained above are described in terms of computer software and hardware. The techniques described can constitute machine-executable instructions embodied within a tangible or non-transitory machine (e.g., computer) readable storage medium, that when executed by a machine will cause the machine to perform the operations described. A tangible machine-readable storage medium includes any mechanism that provides (i.e., stores) information in a form accessible by a machine (e.g., a computer, network device, personal digital assistant, manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-readable storage medium includes recordable/non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.). Additionally, the processes can be embodied within hardware, such as an application specific integrated circuit (“ASIC”) or otherwise.
The above description of illustrated embodiments of the invention, including what is described in the abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. These modifications can be made to the invention in light of the above detailed description.
The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
Claims
1. A display panel for use with a multi-panel display, the display panel comprising:
- a display panel including an array of display pixels disposed surrounded by a bezel, the array of display pixels for emitting a display image having a first size; and
- an optical expansion layer disposed over the array of display pixels to magnify the display image to have a second size that appears larger than the first size and that at least partially conceals the bezel surrounding the housing, wherein the optical expansion layer includes: a first array of microlenses optically coupled to the array of display pixels to cause light from the display pixels to diverge; a second array of microlenses having complementary optical power to the first array of microlenses; and an optically transparent offset layer disposed between the first and second arrays of microlenses.
2. The display panel of claim 1 wherein there is a one-to-one correspondence between optical elements of the first array an optical elements in the second array.
3. The display panel of claim 1 wherein optical elements in the first array are substantially optically aligned with their corresponding optical element in the second array.
4. The display panel of claim 1 wherein the second array of microlenses are laterally offset relative to the first array of microlenses.
5. The display panel of claim 4 wherein the second array of microlenses has an irregular layout pattern to reduce an appearance of seams between adjacent display panels when the display panel is included in the multi-panel display.
6. The display panel of claim 1 wherein there is a one-to-many correspondence between optical elements of the second array and optical elements in the first array.
7. The display panel of claim 1 wherein the optical elements of the first array cause light received from one or more pixels to diverge such that the light exiting the optical elements appears to originate from an image plane behind their array of display pixels.
8. The display panel of claim 1 wherein the optical elements of the first array and the optical elements in the second array can be randomized to have a regular pattern, such that light is directed between optical elements in the first array an optical elements of the second array along oblique optical paths.
9. The display panel of claim 1 wherein the offset layer, the first array, and the second array are formed as a single piece.
10. The display panel of claim 9 wherein the microlenses of the first array are formed as voids in one surface of the offset layer.
11. The display panel of claim 9 wherein the single piece is adhered to the array of display pixels.
12. The display panel of claim 1 wherein the display panel and the optical expansion layers are both non-planar.
13. The display panel of claim 1 wherein one or both of the display panel and the optical expansion layer are flexible.
14. The display panel of claim 1 wherein microlenses in the first and second arrays closest to the edges of the optical expansion layer are tilted.
15. The display of claim 1, further including a mechanism to translate, rotate, or both rotate and translate the microlenses in the first array, the microlenses in the second array, or the microlenses in both the first array and the second array.
16. A tiled multi-panel display comprising a plurality of display panels tiled together along at least one edge of each display panel, each display panel comprising:
- an array of display pixels disposed surrounded by a bezel, the array of display pixels for emitting a display image having a first size; and
- an optical expansion layer disposed over the array of display pixels to magnify the display image to have a second size that appears larger than the first size and that at least partially conceals the bezel surrounding the housing, wherein the optical expansion layer includes: a first array of microlenses optically coupled to the array of display pixels to cause light from the display pixels to diverge; a second array of microlenses having complementary optical power to the first array of microlenses; and an optically transparent offset layer disposed between the first and second arrays of microlenses.
17. The multi-panel display of claim 16 wherein in at least one display panel optical elements in the first array are substantially optically aligned with their corresponding optical element in the second array.
18. The multi-panel display of claim 16 wherein in at least one display panel the second array of microlenses are laterally offset relative to the first array of microlenses.
19. The multi-panel display of claim 18 wherein in at least one display panel the second array of microlenses has an irregular layout pattern to reduce an appearance of seams between adjacent display panels.
20. The multi-panel display of claim 16 wherein in at least one display panel the optical elements of the first array cause light received from one or more pixels to diverge such that the light exiting the optical elements appears to originate from an image plane behind their array of display pixels.
21. The multi-panel display of claim 16 wherein in at least one display panel the optical elements of the first array and the optical elements in the second array can be randomized to have a regular pattern, such that light is directed between optical elements in the first array an optical elements of the second array along oblique optical paths.
22. The multi-panel display of claim 16 wherein in at least one display panel the offset layer, the first array, and the second array are formed as a single piece.
23. The multi-panel display of claim 16 wherein each display panel is non-planar.
24. The multi-panel display of claim 16 wherein the display panels are flexible.
25. The multi-panel display of claim 16 wherein in at least one display panel microlenses in the first and second arrays closest to the edges of the optical expansion layer are tilted.
26. The multi-panel display of claim 16, wherein at least one display panel further includes a mechanism to translate, rotate, or both rotate and translate the microlenses in the first array, the microlenses in the second array, or the microlenses in both the first array and the second array.
Type: Application
Filed: Jan 30, 2013
Publication Date: Oct 24, 2013
Applicant: Google Inc. (Mountain View, CA)
Inventors: Johnny Lee (Mountain View, CA), Eric Teller (Palo Alto, CA)
Application Number: 13/754,732
International Classification: G02B 3/00 (20060101);