WO2021118896A1

WO2021118896A1 - Near-eye transparent display

Info

Publication number: WO2021118896A1
Application number: PCT/US2020/063524
Authority: WO
Inventors: Xuejun Xie
Original assignee: Xuejun Xie
Priority date: 2019-12-01
Filing date: 2020-12-07
Publication date: 2021-06-17
Also published as: WO2021118896A8

Abstract

There is disclosed a transparent light field display device including a polarizing filter, an array of light-emitting picture elements that emit polarized light formed on a transparent substrate, and a transparent microlens array formed over the array of light-emitting picture elements. The polarization of light from the light-emitting picture element is orthogonal to the light passing through the polarizing filter. The transparent microlens array converges the light from the light-emitting element into viewer's eyes and transparent to the light that passes through the polarizing filter. When the transparent light field display device is disposed of the transparent microlens array proximate to a viewer's eye, the unscattered environment light passing through the polarizing filter allows viewer to see objects beyond the transparent light field display device and the light from light-emitting picture elements converge into viewer's eyes and form images on the retina.

Description

NEAR-EYE TRANSPARENT DISPLAY

RELATED APPLICATION INFORMATION

[0001] This patent claims priority from the provisional patent applications 62/942, 149, field 10 December 2019, titled TRANSPARENT SEE-THROUGH DISPLAY, which is incorporated herein by reference.

NOTICE OF COPYRIGHTS AND TRADE DRESS

[0002] A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever.

BACKGROUND

[0003] Field

[0004] This patent relates to virtual and augmented reality display systems. More specifically, the present invention is a method and apparatus for a portable light field near eye see-through display.

[0005] Description of the Related Art

[0006] Near-eye light-field display with large FOV and small form factor is required to make thin and light augmented reality glasses with immersive user experience. Microlens array and light-emitting picture elements in combination can make light field display with small form factor, large FOV, and digitally tunable eye box/relief, thus a good fit for consumer application. However, viewer can not see through the microlens array. It’s important to have an optical design to make microlens array that’s transparent to the light that’s coming from environment and converge the light from light-emitting picture elements into viewer’s eye to form picture on the retina.

DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a schematic cross-sectional view of a transparent microlens light field display device.

[0008] FIG. 2 is schematic cross-sectional views of different designs of polarization selective microlens.

[0009] FIG. 2 is schematic cross-sectional views of another different designs of polarization selective microlens.

[0010] Throughout this description, elements appearing in figures are assigned three- digit reference designators, where the most significant digit is the figure number where the element is introduced, and the two least significant digits are specific to the element. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having the same reference designator.

DETAILED DESCRIPTION [0011] Description of Apparatus

[0012] FIG.l shows the concept of see-through light field display. 101 is the polarizing filter, which could be linear or circular polarizing filter, that is transparent to 104 the light with certain polarization and block 105 the light with polarization that’s orthogonal to 104. 102 is the light-emitting picture elements on transparent substrate that emit polarized light, which could be linear or circular polarization that is orthogonal to 104 and has the same polarization as 105. 102 is transparent. 103 is polarization selective microlens that only converges the light from light-emitting picture element 102 with polarization as 105 and transparent to the light with polarization as 104. The light emitted by 102 may emit in all direction, and the direction away from viewer’s eye 106 will be blocked by 101, which prevents exposing the information to outside viewer to preserver privacy. The eye 106 will see both converged light from 102 and light 104 that passes through all the structure. 103 is also tunable by applying electric voltage or current that can adjust the focus. In another configuration, each lens in 103 could be individually tunable and addressable with control circuit.

[0013] FIG. 2 shows certain ways to realize the polarization selective microlens with tunable focus. 203 is fabricated microlens, which is coated with electrically conductive material 201. 204 is liquid crystal. 202 is a plate coated electrically conductive material and then covered with liquid crystal alignment material so that the liquid crystal is aligned to affect the light with certain polarization. By applying voltage between 201 and 202, the reflective index of 204 can be tuned to change the focus of 203.

[0014] In another configuration, 201 can also be a flat transparent conductive material with a hole 205 on a transparent substrate as a replacement of 203 that function as a lens with applied voltage between 201 and 202.

[0015] In another configuration, 203 can be Fresnel lens 206 which’ s also coated with conductive material 201.

[0016] In another configuration, 203 can be patterned phase modulation elements 207 that are coated with conductive material 201.

[0017] FIG. 3 shows another ways to realize the tunable polarization selective microlens. 302 is covered with patterned conductive material 301 as electrodes and voltage is applied between the electrodes on 301. Between 302 and 303 is liquid crystal material 204. The voltage applied on 302 electrodes creates gradients of electric field that creates gradient of reflective index on 203 which works as lens. 303 is coated with liquid crystal alignment material so that the lens converges the light with certain polarization as the light from 102 while transparent to the other orthogonal polarization as the light 104. [0018] 304 is a metamaterial lens with tunable focus by tuning the carrier density with applied voltage or current through the phase-shifting elements 305. The metamaterial lens is array of phase modulation elements. The metamaterial lens is designed so that it converges the light with certain polarization as the light from 102 while transparent to the other orthogonal polarization as the light 104. By apply voltage or current to the 305, the material’s dielectric constant changes to change the focus.

[0019] 306 is another design of the metamaterial lens 307 that converges the polarized light from light-emitting picture elements 102 and rotate the polarization of the light 90 degrees into the orthogonal polarization. Environment light 104 partially pass through 306 and partially diverged by 306 with the polarization rotated 90 degrees. 308 is a polarizing filter that blocks the light with the same polarization as 102, that include diverged light from 104, and passes the light with the same polarization as 104, that include the converged light from 102. The converged light and the unscattered environment light have the same polarization after passing through 306 and pass through 308. The phase-shifting element on 307 can also be tuned by applying voltage or current to change the dielectric constant and the focus of the microlens.

[0020] Closing Comments

[0021] Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. Although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. With regard to flowcharts, additional and fewer steps may be taken, and the steps as shown may be combined or further refined to achieve the methods described herein. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments.

[0022] As used herein, “plurality” means two or more. As used herein, a “set” of items may include one or more of such items. As used herein, whether in the written description or the claims, the terms “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’, respectively, are closed or semi-closed transitional phrases with respect to claims. Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. As used herein, “and/or” means that the listed items are alternatives, but the alternatives also include any combination of the listed items.

Claims

CLAIMS It is claimed:

1. A transparent light field display device, comprising: a polarizing filter; an array of light-emitting picture elements formed on the transparent substrate that emits polarized light that’s orthogonal to the light passing through the polarizing filter; and a microlens array formed over the array of light-emitting picture elements, the microlens array is transparent to the polarized light that passes through the polarizing filter and converges the polarized light from the light-emitting picture elements, wherein, when the transparent light field display device is disposed with the microlens array proximate to viewer’s eye, the microlens array is transparent for the light passing through the polarizing filter allowing viewer to see objects beyond the transparent light field display device, while the light emitted by the light-emitting picture elements is converged by the microlens array and form image in viewer’s retina, and the light from the light-emitting elements in the direction away from viewer’s eye is blocked by the polarizing filter to preserve privacy.

2. The transparent light field display device of claim 1, wherein a layer of liquid crystal is filled between microlens, that covered with conductive material, and sheet of transparent material, that coated with liquid crystal alignment material on top of conductive material, where the liquid crystal’s reflective index can be actively tuned by applying electrical voltage to the two conductive surfaces.

3. The microlens of claim 2, wherein the microlens is replaced by opening a window on one of the conducting surfaces.

4. The microlens of claim 2, wherein the microlens is Fresnel lens.

5. The microlens of claim 2, wherein the microlens is composed of phase tuning elements.

6. The transparent light field display device of claim 1, wherein a layer of liquid crystal is filled between two sheets of transparent materials where one of the sheets has electrically biased electrodes that create gradient of change of reflective index that functions as lens, and the other sheet is coated with liquid crystal alignment material.

7. The transparent light field display device of claim 1, wherein the microlens is composed of phase tuning elements whose dielectric constant are tunable by applying bias or current, that tunes the focus.

8. The transparent light field display device of claim 1, wherein the microlens is composed of semi-transparent phase tuning elements where the phase tuning elements converge the light emitted from polarized light-emitting picture elements and rotate the polarization 90 degrees and pass through a polarizing filter same as in claim 1.