Optical Method and System for Light Field (LF) Displays Based on Tunable Liquid Crystal (LC) Diffusers

Abstract

To solve some problems with many 3D volumetric displays, which are their low resolution, large physical size and high manufacturing costs.SOLUTION: Some embodiments of an example apparatus may include: a display; a first controllable diffuser overlaying the display, the first controllable diffuser being selectively operable to diffuse light in a first diffusion direction; and a second controllable diffuser overlaying the display, the second controllable diffuser being selectively operable to diffuse light in a second diffusion direction substantially perpendicular to the first diffusion direction.SELECTED DRAWING: Figure 14A

Description

[Technical Field]

[0001] The present invention relates to an optical method and system for a light field (LF) display based on a tunable liquid crystal diffuser (LC). [Background technology]

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a nonprovisional adaptation of and claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62 / 868,687, entitled "OPTICAL METHOD AND SYSTEM FOR LIGHT FIELD (LF) DISPLAYS BASED ON TUNABLE LIQUID CRYSTAL (LC) DIFFUSERS," filed June 28, 2019, which is incorporated herein by reference in its entirety.

[0003] The human mind perceives and determines the depth of observed objects in part by receiving signals from the muscles used to orient each eye. The brain associates the relative angular orientation of the eyes with the determined depth of focus. Correct focus cues result in natural blurring of objects outside the observed plane of focus and natural dynamic parallax effects. One type of 3D display capable of providing correct focus cues uses volumetric display techniques, which can generate 3D images in true 3D space. Each "voxel" in a 3D image is physically located at a spatial location and reflects or emits light from that location toward the observer, forming a real image in the viewer's eye. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 7,994,527 [Patent Document 2] U.S. Patent No. 7,518,149 [Patent Document 3] U.S. Patent No. 9,664,914 [Patent Document 4] U.S. Patent No. 9,709,851 [Patent Document 5] International Publication No. 2011014743 Brochure [Patent Document 6] International Publication No. 2012025786 Brochure [Patent Document 7] U.S. Patent No. 7,408,601 [Patent Document 8] U.S. Patent No. 9,709,829 [Patent Document 9] International Publication No. 2016135434 Brochure [Patent Document 10] International Publication No. 2016140851 Brochure [Patent Document 11] U.S. Patent Application No. 2010 / 0079584 [Patent Document 12] U.S. Patent No. 9,462,261 [Patent Document 13] International Publication No. 2005011292 Brochure [Patent Document 14] International Publication No. 02059691 Brochure [Patent Document 15] International Publication No. 2017055894 Brochure [Patent Document 16] U.S. Patent Application No. 2015 / 0056561 [Patent Document 17] U.S. Patent No. 9,568,885 [Patent Document 18] U.S. Patent No. 9,250,446 [Non-patent literature]

[0005] [Non-Patent Document 1] Vincent W.Lee,Nancy Twu, & Ioannis Kymissis,Micro-LED Technologies and Applications,6 / 16 INFORMATION DISPLAY 16-23(2016) [Non-patent document 2] Francois Templier,et al.,A Novel Process for Fabricating High-Resolution and Very Small Pixel-pitch GaN LED Microdisplays,2017 DIGEST 268-271(2017) [Non-patent document 3] Shang,Xiaobing,et al.,Fast Switching Cholesteric Liquid Crystal Optical Beam Deflector with Polarization Independence,SCIENTIFIC REPORTS Jul 26;7(1):6492 (2017)(“Shang”) [Non-patent document 4] YP. Huang,et al.,Autostereoscopic 3D Display with Scanning Multi-Electrode Driven Liquid Crystal(MeD-LC)Lens,1:1 3D RESEARCH 39-42(2010) [Non-patent document 5] H. Wang,et al.,Large-aperture transparent beam steering screen based on LCMPA,55:28 APPLIED OPTICS(2016) [Non-patent document 6] P. McManamon, et al.,A Review of Phased Array Steering for Narrow-Band Electrooptical Systems,97:6 PROCEEDINGS OF THE IEEE 1078-96(2009) [Non-Patent Document 7] Xiangyu Zhang, et al.,A Novel Spatio-Temporal Multiplexing Multi-view 3D Display,IEEE CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM(CLEO-PR)(2017) [Non-patent document 8] X. Xia,et al.,Time-Multiplexed Multi-view Three-Dimensional Display with Projector Array and Steering Screen,26:12 OPTICS EXPRESS 15528-38(2018) [Non-Patent Document 9] G. Love,et al.,High-Speed ​​Switchable Lens Enables the Development of A Volumetric Stereoscopic Display,17(18)OPTICS EXPRESS 15716-25(2009) [Non-Patent Document 10] N. Matsuda, A.Fix. & D.Lanman, Focal Surface Displays, 36(4)ACM TRANSACTIONS ON GRAPHICS 1-14(2017) [Non-Patent Document 11] L. Commander,S.Day,& D.Selviah;Variable Focal Length Microlenses,177:1-6 OPTICS COMMUNICATIONS 157-170 (2000) [Non-Patent Document 12] L. Commander,S.Day,& D.Selviah; Variable Focal Length Microlenses, 177:1-6 OPTICS COMMUNICATIONS 157-170(2000) [Non-Patent Document 13] H. Chen,et al.,A Low Voltage Liquid Crystal Phase Grating with Switchable Diffraction Angles 7 NATURE SCIENTIFIC REPORTS,Article No.39923(2017)(“Chen”)and Y.Ma,et al.,Fast Switchable Ferroelectric Liquid Crystal Gratings with Two Electro-Optical Modes,6:3 AIP ADVANCES,Article No.035207,(2016) [Non-Patent Document 14] A. Moheghi et al.,PSCT for Switchable Transparent Liquid Crystal Displays,46:1 SID 2015 DIGEST(2015)and J.Ma,L.Shi,&D-K.Yang,Bistable Polymer Stabilized Cholesteric Texture Light Shutter,3:2 APPLIED PHYSICS EXPRESS(2010) [Non-Patent Document 15] R. Yamaguchi,et al,Normal and Reverse Mode Light Scattering Properties Nematic Liquid Crystal Cell Using Polymer Stabilized Effect;28:3 J.PHOTOPOLYMER SCI.AND TECH.319-23(2015) [Non-Patent Document 16] G. Nabil Hassanein,Optical Tuning of Polymer Stabilized Liquid Crystals Refractive Index; 5(3):3 J.Lasers,Optics & Photonics(2018) Summary of the Invention [Problem to be solved by the invention]

[0006] Some problems with many 3D volumetric displays are their low resolution, large physical size, and high manufacturing costs, which can make them too cumbersome for use outside of, for example, product exhibits, museums, and shows. [Means for solving the problem]

[0007] An exemplary device according to some embodiments may include a display, a first controllable diffuser overlaying the display, the first controllable diffuser selectively operable to diffuse light in a first direction, and a second controllable diffuser overlaying the display, the second controllable diffuser selectively operable to diffuse light in a second direction substantially perpendicular to the first direction.

[0008] For some embodiments of the exemplary device, the display can be a multi-view display.

[0009] For some embodiments of the exemplary apparatus, at least one of the first controllable diffuser and the second controllable diffuser may include a surface effect liquid crystal (SELC) diffuser.

[0010] For some embodiments of the exemplary device, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and at least one of the LC material layer and the first and second substrates can be configured to perform angle-selective diffusion of light.

[0011] For some embodiments of the exemplary device, the device can include at least one liquid crystal (LC) grating.

[0012] For some embodiments of the exemplary apparatus, at least one of the at least one LC diffraction grating and the first and second controllable diffusers may include a birefringent material.

[0013] Some embodiments of the exemplary device may further include a sensor configured to detect an orientation of the display, and the device may be configured to switch between selectively operating the first controllable diffuser to diffuse in a first direction and selectively operating the second controllable diffuser to diffuse in a second direction in response to a detected change in orientation of the display.

[0014] For some embodiments of the exemplary device, at least one of the first controllable diffuser and the second controllable diffuser can be configured to be selectively activated without mechanical movement.

[0015] In some embodiments of the exemplary device, at least one of the first controllable diffuser and the second controllable diffuser can be configured to diffuse light in response to an applied electric field.

[0016] An exemplary optical element according to some embodiments can include a first layer comprising electrically tunable liquid crystals capable of changing the polarization state of light passing through the first layer depending on the state of the electrical tuning; and a second layer comprising birefringent material in a layer parallel to the first layer including surface structures designed to impart alternating diffusion properties to the beam, wherein the second layer can be configured to scatter light incident on the second layer according to a first angular pattern when the polarization state of the light is in a first polarization state, and the second layer can be configured to scatter light incident on the second layer according to a second angular pattern when the polarization state of the light is in a second polarization state.

[0017] For some embodiments of the exemplary optical element, the second layer can be configured to diffuse light in a horizontal direction when the polarization state of the light is in a first polarization state, and the second layer can be configured to diffuse light in a vertical direction when the polarization state of the light is in a second polarization state.

[0018] Some embodiments of the exemplary device may further include a plurality of light emitting elements and collimating microlenses capable of generating a collimated beam of light, and a directionally controllable diffuser capable of switching between a first state in which the light is diffused in a first direction and a second state in which the light is diffused in a second direction.

[0019] For some embodiments of the exemplary optical element, the directionally controllable diffuser can be configured to diffuse in the vertical direction, and the device can be configured such that when the device is in portrait orientation, only a single vertical view is produced.

[0020] For some embodiments of the exemplary optical element, at least some of the plurality of light-emitting elements may be arranged in a plus-shaped pattern.

[0021] For some embodiments of the exemplary optical element, in response to rotation of the device, the direction-controllable diffuser can be enabled to diffuse in the rotated direction, and the device can be configured such that when the display orientation is changed from portrait to landscape, only a single view is generated in the direction of diffusion.

[0022] Some embodiments of the exemplary device may further include a three-dimensional (3D) display, and the directional controllability of the diffuser may be patterned across the 3D display, allowing for spatially varying diffusion directional characteristics.

[0023] An exemplary method according to some embodiments may include emitting a light beam from one or more light-emitting devices, polarizing the light beam into a linearly polarized beam, passing the light beam through a liquid crystal (LC) material, passing the light beam through a birefringent material, and applying a voltage to the LC material to change the light polarization configuration state of the LC material, where changing the light polarization configuration state switches from a first polarization state to a second polarization state, where the first polarization state spreads the light beam in a first direction when passing through the birefringent material and the second polarization state spreads the light beam in a second direction when passing through the birefringent material.

[0024] Some embodiments of the exemplary method may further include rendering one or more images for a light field (LF) display device and sending the one or more rendered images to the LF display device.

[0025] Some embodiments of the example method may further include receiving a field of view (FOV) selection for the LF display device.

[0026] Some embodiments of the example method may further include adjusting the brightness of the emitted light beam based on the FOV selection.

[0027] An exemplary apparatus according to some embodiments can include an array of light-emitting devices, a polarizer layer, a microlens array (MLA), one or more diffusers, and one or more diffraction gratings.

[0028] For some embodiments of the exemplary apparatus, the array of light-emitting devices may include one or more sets of light-emitting devices.

[0029] For some embodiments of the exemplary apparatus, each of the one or more sets of light-emitting devices can include a pixel.

[0030] Some embodiments of the example method may further include a backboard and one or more baffles, wherein the array of one or more sets of light-emitting devices is mounted on the backboard, each set of light-emitting devices in the array corresponding to a respective baffle, and each baffle at least partially separating each set of light-emitting devices from the remainder of the array of one or more sets of light-emitting devices.

[0031] For some embodiments of the exemplary apparatus, at least one of the one or more diffusers may be configured to diffuse light emitted by at least one of the light-emitting devices in a horizontal direction, and at least one of the one or more diffusers may be configured to diffuse light emitted by at least one of the light-emitting devices in a vertical direction.

[0032] For some embodiments of the exemplary apparatus, at least one of the one or more diffusers can be configured to switch between diffusing light emitted by at least one of the light-emitting devices in a horizontal direction and diffusing light in a vertical direction.

[0033] For some embodiments of the exemplary device, at least one of the one or more diffusers can be a surface effect liquid crystal (SELC) diffuser.

[0034] For some embodiments of the exemplary device, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and the LC material layer can be configured to cooperate with the first substrate and the second substrate to cause angle-selective diffusion of light in response to an applied voltage.

[0035] For some embodiments of the exemplary device, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and the LC material layer and the first and second substrates can have selected material and interface properties that work in conjunction to scatter the light beam.

[0036] For some embodiments of the exemplary device, at least one of the diffusers can be configured to switch between a 2D display mode and a 3D display mode.

[0037] For some embodiments of the exemplary device, a first one of the diffusers can be a SELC diffuser configured to scatter light displaying a first image using a first diffusion direction, and a second one of the diffusers can be a SELC diffuser configured to scatter light displaying a second image using a second diffusion direction, and the first diffusion direction can be orthogonal to the second diffusion direction.

[0038] For some embodiments of the exemplary apparatus, at least one of the diffusers can be a SELC diffuser configured to diffuse light to reduce glare on the image projected by the array of light-emitting devices.

[0039] For some embodiments of the exemplary device, at least one of the gratings can include a liquid crystal material.

[0040] For some embodiments of the exemplary device, at least one of the diffraction gratings can include a birefringent material.

[0041] For some embodiments of the exemplary apparatus, at least one of the one or more diffusers can be configured as a mosaic diffuser to together diffuse one or more neighboring light beams emitted by one or more of the light-emitting devices. [Effects of the Invention]

[0042] A novel optical method and system for a light field (LF) display based on a tunable liquid crystal (LC) diffuser is provided. [Brief explanation of the drawings]

[0043] [Figure 1A] FIG. 1 is a diagram of an exemplary communication system according to some embodiments. [Figure 1B] 1B is a diagram of an exemplary wireless transmit / receive unit (WTRU) that can be used within the communication system of FIG. 1A in accordance with some embodiments. [Figure 2] FIG. 2 illustrates an exemplary handset display in a first configuration of some embodiments. [Figure 3A] FIG. 10 illustrates an exemplary handset display in a second configuration of some embodiments. [Figure 3B] FIG. 10 illustrates an exemplary handset display in a third configuration of some embodiments. [Figure 4A] FIG. 2 illustrates an exemplary multi-view 3D display in a first configuration of some embodiments. [Figure 4B] FIG. 2 illustrates an exemplary multi-view 3D display in a second configuration of some embodiments. [Figure 4C] FIG. 10 illustrates an exemplary multi-view 3D display in a third configuration of some embodiments. [Figure 5] FIG. 1 illustrates an exemplary 3D light field display with image zones on both sides of the device according to some embodiments. [Figure 6A] FIG. 1 illustrates an exemplary 3D light field display with an exemplary small viewing zone of some embodiments. [Figure 6B] FIG. 1 illustrates an exemplary 3D light field display with an exemplary large viewing zone of some embodiments. [Figure 7A] FIG. 1 is a diagram of an ideal case of perfect collimation without any beam divergence caused by one or more geometric factors, according to some embodiments. [Figure 7B] 1A-1C are diagrams of exemplary beam divergence caused by one or more geometric factors in some embodiments. [Figure 7C] 1A-1C are diagrams of exemplary beam divergence caused by one or more geometric factors in some embodiments. [Figure 7D] 1A-1C are diagrams of exemplary beam divergence caused by diffraction and a first aperture size for some embodiments. [Figure 7E] 10A-10C are diagrams of exemplary beam divergence caused by diffraction and second aperture size for some embodiments. [Figure 7F] 10A-10C are diagrams of exemplary beam divergence caused by diffraction and a third aperture size for some embodiments. [Figure 8A] 1 is a diagram of an exemplary image magnifying lens having a first optical power according to some embodiments. [Figure 8B] FIG. 2 is a diagram of an exemplary image magnifying lens having a second optical power according to some embodiments. [Figure 8C] FIG. 1 is a diagram of an exemplary image magnifying lens having a third optical power according to some embodiments. [Figure 9A]1 is a diagram of an exemplary first light source and lens configuration according to some embodiments. [Figure 9B] 1A-1C are diagrams of exemplary second light source and lens configurations according to some embodiments. [Figure 9C] FIG. 10 is a diagram of an exemplary third light source and lens configuration according to some embodiments. [Figure 9D] FIG. 10 is a diagram of an exemplary fourth light source and lens configuration according to some embodiments. [Figure 10] FIG. 1 is a diagram of an exemplary variable focal length microlens array according to some embodiments. [Figure 11A] 1A and 1B are diagrams of exemplary two-component SELC diffusers in a light beam transmission state according to some embodiments. [Figure 11B] FIG. 1 is a diagram of an exemplary two-component SELC diffuser in a light beam diverging state according to some embodiments. [Figure 12A] 1 is a diagram of an exemplary single-component SELC diffuser in a light beam transmission state according to some embodiments. [Figure 12B] FIG. 1 is a diagram of an exemplary single-component SELC diffuser in a light beam diffusion state according to some embodiments. [Figure 13A] FIG. 10 is a diagram of an exemplary SELC diffuser with a smaller divergence angle according to some embodiments. [Figure 13B] 1A-1C are diagrams of exemplary SELC diffusers with larger divergence angles according to some embodiments. [Figure 14A] FIG. 1 illustrates an exemplary SELC diffuser that allows for horizontal diffusion according to some embodiments. [Figure 14B] FIG. 1 is a diagram of an exemplary SELC diffuser that allows for vertical diffusion according to some embodiments. [Figure 15] FIG. 1 is a diagram of an exemplary 3D light field optical display structure according to some embodiments. [Figure 16A] FIG. 10 is a diagram of an exemplary light emitter matrix layout for a full-color image using four sub-pixels for each full-color beam, according to some embodiments. [Figure 16B] FIG. 10 is a diagram of an exemplary light emitter matrix layout for a full-color image using three sub-pixels for each full-color beam according to some embodiments. [Figure 17] 1A-1C are schematic diagrams illustrating an exemplary 3D display in portrait and landscape modes according to some embodiments. [Figure 18] 1A-1C illustrate exemplary 3D display structures with tunable LC gratings according to some embodiments. [Figure 19] FIG. 1 is a schematic diagram illustrating an exemplary mobile device viewing configuration according to some embodiments. [Figure 20] FIG. 1 illustrates an exemplary μLED pattern layout according to some embodiments. [Figure 21] FIG. 2 is a diagram of an exemplary display optics configuration according to some embodiments. [Figure 22A] FIG. 10 is an example simulated irradiance distribution without a diffuser according to some embodiments. [Figure 22B] 10A-10C illustrate exemplary simulated irradiance distributions with a SELC diffuser according to some embodiments. [Figure 22C] 10A-10C illustrate exemplary simulated irradiance distributions using a SELC diffuser and a diffraction grating according to some embodiments. [Figure 22D] 10A-10C are diagrams of exemplary simulated irradiance distributions when horizontal and vertical diffusers are activated according to some embodiments. [Figure 23] 10 is a graph of an exemplary horizontal irradiance distribution for a deactivated horizontal diffuser and diffraction grating of some embodiments. [Figure 24] 10 is a graph of exemplary vertical irradiance distributions for three configurations of some embodiments. [Figure 25] 10 is a graph of an exemplary irradiance distribution for the horizontal direction of the light source with a horizontal diffuser, a vertical diffuser, and a diffraction grating according to some embodiments. [Figure 26] FIG. 1 is a message sequence diagram of an exemplary process for processing and displaying 3D imagery according to some embodiments. [Figure 27] 1 is a flowchart of an exemplary process for processing and rendering 3D imagery in accordance with some embodiments. [Figure 28] 1 is a flowchart of an exemplary process for processing and rendering 3D imagery according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0044] The entities, connections, arrangements, etc. depicted in and described in relation to the various figures are offered by way of example, not limitation. As such, any and all statements or other indications regarding what a particular figure "depicts," what a particular element or entity within a particular figure "is," or what "has," and any and all similar statements that, in isolation and out of context, may be read as absolute and therefore limiting, can only properly be read as constructively preceded by a phrase such as "in at least one embodiment...." For purposes of brevity and clarity of presentation, this implied precedent phrase will not be persistently repeated in the Detailed Description.

[0045] For example, a wireless transmit / receive unit (WTRU) may be used as the light field display device in some embodiments described herein.

[0046] 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may utilize one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailed unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multicarrier (FBMC).

[0047] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspot or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain situations), consumer electronics devices, and devices operating on commercial and / or industrial wireless networks. Any of the WTRUs 102a, 102b, 102c, 102d may be referred to interchangeably as a UE.

[0048] The communications system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNodeB, a Home Node B, a Home eNodeB, a gNB, a New Radio (NR) Node B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0049] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, sometimes referred to as a cell (not shown). These frequencies may be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectrum. A cell may provide coverage for a wireless service in a particular geographic area, which may be relatively constant or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, e.g., one for each sector of the cell. In an embodiment, the base station 114a may utilize multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell, e.g., beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0050] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0051] More specifically, as mentioned above, the communication system 100 may be a multiple-access system and may utilize one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a and the WTRUs 102a, 102b, and 102c in the RAN 104 / 113 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0052] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE), and / or LTE Advanced (LTE-A), and / or LTE Advanced Pro (LTE-A Pro).

[0053] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as New Radio (NR) radio access, which may establish the air interface 116 using NR.

[0054] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access, e.g., using a dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0055] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0056] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., used by drones), and a roadway. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 through the CN 106.

[0057] The RAN 104 / 113 can communicate with the CN 106, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data can have various quality of service (QoS) requirements, such as different throughput, delay, error resilience, reliability, data throughput, and mobility requirements. The CN 106 can provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 / 113 and / or the CN 106 can communicate directly or indirectly with other RANs that utilize the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 may also communicate with another RAN (not shown) that utilizes GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0058] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communications protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communications networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may utilize the same RAT as the RAN 104 / 113 or a different RAT.

[0059] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.) For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that may utilize cellular-based wireless technology and with a base station 114b that may utilize IEEE 802 wireless technology.

[0060] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any subcombination of the above elements while remaining consistent with an embodiment.

[0061] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0062] The transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 can be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive both RF and light signals. It will be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0063] 1B, the transmit / receive element 122 is depicted as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0064] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0065] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may obtain information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may obtain information from and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0066] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components within the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0067] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from base stations (e.g., base stations 114a, 114b) and / or may determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information using any suitable location-determination method while remaining consistent with an embodiment.

[0068] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, a direction sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0069] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and the downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference either through hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0070] 1A-1B and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, the base stations 114a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0071] The emulation device can be designed to perform one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more emulation devices can perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices can perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0072] The one or more emulation devices can perform one or more functions, including all functions, without being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices can be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to perform tests of one or more components. The one or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may, for example, include one or more antennas) can be used by the emulation devices to transmit and / or receive data.

[0073] Many previous 3D displays can be classified into four exemplary categories based on their form factor: head-mounted displays / devices (HMDs), volumetric 3D displays, screen-based 3D displays, and holographic displays. The exemplary categories are for illustrative purposes only and may overlap in some cases and examples, for example.

[0074] Many head-mounted devices (HMDs) take up less space and can be made with smaller components and fewer materials than goggle-less devices, which can translate to lower costs. However, because head-mounted VR goggles and smart glasses are single-user devices, such devices do not enable as natural a shared experience as goggle-less solutions.

[0075] Volumetric 3D displays take up space in all three spatial directions and can require a lot of physical material, making many such devices heavy, expensive to manufacture, and difficult to transport. Due to their heavy use of material, volumetric displays also tend to have small "windows" and limited fields of view (FOV).

[0076] Screen-based 3D displays generally have a single large, flat screen and a device that projects an image into free space from a distance. These devices can be more compact for transportation and, for example, can have a larger FOV than volumetric displays. Many of these devices are complex and expensive, requiring a projector subassembly. Many such devices also require precise alignment between different parts, for example. While flat form-factor 3D displays can require a lot of space in two spatial directions, because the third direction is only virtual, such devices can be relatively easy to transport to and assemble in different environments. Because the devices are flat, some of the optical components can be manufactured in sheet or roll format, making them relatively low-cost in large quantities.

[0077] Another type of 3D display device capable of providing the correct retinal focal cues is a holographic display, which aims to reconstruct the entire light wavefront scattered from an object in the natural environment. Many such devices lack a suitable spatial light modulator (SLM) component that can be used to generate a highly detailed wavefront.

[0078] A further type of 3D display technology capable of providing natural retinal focal cues is called a light field (LF) display. LF display systems can generally be designed to generate a so-called light field, which represents light rays traveling in all directions in space. LF systems generally aim to control the emission of light with high resolution in both the spatial and angular domains. Multi-view 3D displays with very high angular resolution may also be referred to as LF displays. HMDs, volumetric 3D displays, and screen-based displays may all be included as some examples of LF displays.

[0079] In many relatively low-density multi-view imaging displays, the view changes coarsely and gradually as the viewer moves in front of the device. This characteristic degrades the quality of the 3D experience and can even cause a complete breakdown of 3D perception. To mitigate this problem (along with adaptive vergence discrepancy (VAC)-type issues), several super multi-view (SMV) techniques have been tested using as many as 512 views. A very large number of views is generated to ensure any transition between two viewpoints is very smooth. A much more realistic visual experience occurs when light from at least two images from slightly different viewpoints simultaneously enters the eye's pupil. In this case, the brain unconsciously predicts image changes due to motion, so the motion parallax effect more closely resembles natural conditions. The SMV condition can be met by reducing the separation between two views at the correct viewing distance to a value smaller than the size of the eye's pupil. Under normal lighting conditions, the human pupil is typically estimated to be approximately 4 mm in diameter. When ambient light levels are high (e.g., in sunlight), the diameter can be as small as 1.5 mm, and in dark conditions it can be as large as 8 mm. The maximum angular density that can be achieved with an SMV display is limited by diffraction, and there is an inverse relationship between spatial resolution (pixel size) and angular resolution. Diffraction increases the angular spread of a light beam passing through an aperture, and it can often be necessary to take this effect into account in the design of very high-density SMV displays.

[0080] For some embodiments, an adjustable diffuser component capable of angle-selective light diffusion allows for the modification of light beam angular divergence characteristics without moving parts. Such diffusers can include components based on optical interface light scattering effects. For a particular field of view, some embodiments of 3D optical display structures with surface-effect liquid crystal (SELC) adjustable diffusers can have fewer light-emitting components than other devices. For some embodiments, light is emitted from small, separately controllable emitters and collimated using a microlens array. The SELC is used for selective diffusion of the emitted beam when the viewing direction is switched. For some embodiments, such diffusers can be made at a lower cost using fewer emitters than other devices.

[0081] For example, there are so-called "smart windows" that can be transparent and clear in the power-on state and non-transparent in the power-off state. Volume scattering-based LC diffusers have been used in display technologies such as polymer-stabilized liquid crystal (PSLC) or polymer-dispersed liquid crystal (PDLC), which are used in transparent displays or smart glasses. Conventional methods are often understood to be either completely transparent or light-diffusing, without angular dependence.

[0082] Exemplary static light direction controllers and static light shaping diffusers exist that have fixed angular performance. Angular control of the diffusion effect can be used with displays. For example, Luminit is understood to have produced turning films (DTFs) and light shaping diffusers (LSDs), which are static devices with fixed angular performance. The directional characteristics are fixed at the time of manufacture.

[0083] Figure 2 is a diagram illustrating an exemplary handset display in a first configuration, according to some embodiments. Figure 2 shows the handset display and an image seen by three viewers. Wide diffusion in all directions (e.g., 180 degrees) can be used for general multi-user viewing of the image at a first power level. The FOV 202 is, for example, 180 degrees, and viewers 204, 206, and 208 all see the image.

[0084] 3A is a diagram illustrating an exemplary handset display in a second configuration, according to some embodiments. FIG. 3A shows a brighter image with a reduced FOV 302 (e.g., 80 degrees), where the brighter image is seen by only a single viewer 304. For some embodiments, the handset display can use controllable FOV reduction to save power at the expense of reduced FOV.

[0085] Figure 3B is a diagram showing an exemplary handset display in a third configuration, according to some embodiments. Figure 3B shows a lower brightness level compared to Figure 3A, although the FOV 352 is reduced (e.g., 80 degrees). As in Figure 3A, the image in Figure 3B is seen by only one viewer 354. For some embodiments, a moderate level of diffusion can be used to provide a reduced field of view, and by reducing the light emitted as the FOV is reduced, power savings can be achieved without reducing the brightness seen by the primary viewer.

[0086] Multiview LF displays can be based solely on spatial multiplexing. Rows or matrices of light-emitting pixels (display subpixels) can be placed behind a lenticular lens sheet or microlens array, with each pixel projecting into only one viewing direction or a limited set of viewing directions in front of the display structure. The more pixels there are on the light-emitting layer behind each light beam collimating feature, the more views can be generated. This phenomenon can result in a trade-off between spatial resolution and the number of unique views generated. If a 3D display produces smaller LF pixel sizes, the size of the individual subpixels can be reduced and / or fewer viewing directions can be generated. Subpixel sizes can be limited to relatively large areas due to a lack of suitable components. High-quality LF displays can have both high spatial and angular resolution. High angular resolution may be required to meet super multiview (SMV) requirements and can be very difficult to achieve with currently available sources.

[0087] Figures 4A, 4B, and 4C illustrate exemplary multi-view 3D display structures having a first focal length, a second focal length, and a third focal length, respectively, according to some embodiments.

[0088] As an example of optical design issues, Figures 4A and 4B show the case of two integrated imaging multi-view displays in which a lenticular sheet is placed in front of a light emitter array. In the examples of Figures 4A and 4B, the quantity and size of the emitters are the same. The lenticular lenses can be designed to have the same focal length (FL) 402, 432, which is the distance between the lens surface and the source. The lenticular lens optics may be able to generate multiple well-collimated individual beams of light that are used to present the multi-view image in different view directions. Both example cases have the same field of view (FOV) 406, 436, but the structure of Figure 4B has a larger lens aperture 434 that covers five light sources with five depicted views 438, 440, 442, 444, 446 instead of the lens aperture 404 of Figure 4A, which covers three light sources with three depicted views 408, 410, 412, resulting in higher angular resolution. However, because the aperture is larger, the spatial resolution is lower.

[0089] A similar tradeoff can occur between angular view density and total angular range or FOV. By increasing the distance between the microlenses and the emitter and correspondingly decreasing the microlens' refractive power, angular view density can be increased, but the FOV decreases. This tradeoff is illustrated in the case of the display optics depicted in Figures 4B and 4C. Both structures have the same lens aperture size 464, 434, and both structures can generate five different view beams 438, 440, 442, 444, 446, 468, 470, 472, 474, and 476 for each projector cell. However, because the optics of the structure in Figure 4C has a longer FL 462, beams 468, 470, 472, 474, and 476 are projected into a lower FOV 466, and angular density increases.

[0090] Integrated imaging-based LF displays have spatial and angular regions where multiple interlaced beams are used together to generate multiple distinct images. To meet viewing and image uniformity requirements using optical display structures, optical diffusion surfaces are often required. Diffuser structures can be used, for example, to generate volumetric images, improve single-image uniformity, increase the field of view (FOV), and / or provide smoother transitions between neighboring views. A problem associated with many optical diffusers using material dispersions or uniform surface microstructures is that they tend to diffuse light equally in all directions. This characteristic is often undesirable when (1) maintaining high angular resolution in one direction to generate a stereoscopic effect and (2) using diffusion in other directions to increase the FOV so that the image is visible from a larger viewing window. While some holographic diffraction gratings have been developed to address this issue, many such gratings are static components that require highly specialized fabrication methods and are difficult to tailor for different applications. For some embodiments disclosed herein, adjustable diffusers and / or adjustable diffuser components can be used in 3D display structures.

[0091] Many high-quality multi-view displays, classified as light field displays, require a very large number of light sources to achieve sufficiently good resolution (e.g., as determined by the user) in both the spatial and angular domains. The sources are often required to have a very high dynamic range to compensate for optical efficiency differences associated with optical devices that project images at different angular directions. Many μLEDs developed specifically for display applications often have such a dynamic range. One challenge with such μLEDs can be the requirement for extremely high-density assembly of microscale components. Also, because such components need to be individually addressable, arranging electrical connections at a small scale becomes very difficult. Because the number of components is very large and the fabrication of source modules often requires extreme precision, this difficulty often results in high costs.

[0092] FIG. 5 illustrates an exemplary 3D light field display with image zones on both sides of the display, according to some embodiments. There is no light-scattering medium between the 3D display and the viewer, and all areas of the display project emitter images toward both eyes of the viewer. However, in general, to generate a stereoscopic image, a single emitter within the display should not be visible to both eyes simultaneously. This means that the field of view (FOV) of the emitted beam bundle from all parts of the display covers both eyes, but the single beam must have an FOV that is narrower than the distance between the pupils of the two eyes (approximately 64 mm on average) at the viewing distance. The FOV of one display section, and therefore of a single emitter, is determined by the width of the emitter row / emitter and the magnification of the imaging optics.

[0093] To overlap the beam bundle FOVs at a specified viewing distance, the display can be curved, for example, at a certain radius, or the projected beams can be bent toward a specified point, for example, using a flat Fresnel lens sheet. Simple multi-view displays based on emitters and microlenses can also use a technique in which the emitter location is slightly offset relative to the central axis of the collimating lens. If this offset is increased from the central display position toward the display edge, the beam bundles projected from the display edge can overlap with the central beam bundle. If the FOVs do not overlap, some parts of the 3D image may not be formed.

[0094] Due to the limited size of the device and practical limitations on focal length, image zones where 3D images are visible are formed in front of and / or behind the display device. Figure 5 shows an example viewing geometry that can be achieved using a 3D LF display structure. In front of the curved display, there is a 3D image zone limited by the farthest focal length from the display with reasonable spatial resolution and by the total display FOV. Another image zone formed using a virtual extension of the emitted beam can also exist behind the display. Because the viewer is positioned farther away and the eye's resolution is lower, larger voxels can be tolerated behind the display. The maximum image distance can be selected based on the minimum acceptable resolution achievable using expanded beam virtual extension.

[0095] In FIG. 5, the display surface is curved with a radius equal to the specified viewing distance. The overlapping beam bundle FOVs form a viewing zone 512 around the face area of ​​the viewer 514. The size of this viewing zone 512 can determine the amount of allowable movement of the viewer's head. For the viewer 514 to see a stereoscopic image, the pupils of both eyes must be within the zone 512 simultaneously. For some embodiments, the size of the viewing zone 512 can be adjusted by changing the beam bundle FOV. The display 502 can generate a rear image zone 504 behind the display 502 and a front image zone 506 in front of the display 502. The display can generate a display FOV 508 and an LF pixel FOV 510 for the viewer 514. The average pupil distance 516 between each eye is 64 mm. The minimum image distance 518 is the distance from the viewer's eyes to the center of the arc in front of the front image zone 506. Display viewing distance 520 is the distance from the viewer's eyes to the center of the arc of display 502. Maximum image distance 522 is the distance from the viewer's eyes to the center of the arc of the rear surface of rear image zone 504.

[0096] For some embodiments, the light field display structure can perform processes including rendering one or more images for a light field (LF) display device and sending one or more rendered images to the LF display device. For example, the display 502 can receive data and information related to one or more rendered images. The rendered image data can be used to generate images in the front image zone 506 and / or the rear image zone 504.

[0097] FIG. 6A illustrates an exemplary 3D light field display with an exemplary small viewing zone, according to some embodiments. FIG. 6B illustrates an exemplary 3D light field display with an exemplary large viewing zone, according to some embodiments. FIGS. 6A and 6B each illustrate an exemplary viewing geometry. In FIG. 6A, a single viewer sits in front of a display with an image zone 602, and both eye pupils are covered by a small viewing zone 606 achieved using a narrow beam bundle FOV 604. The minimum functional width of the zone is determined by the eye's interpupillary distance (approximately 64 mm on average). A narrow FOV also implies a small tolerance for viewing distance changes, as the eyes, both in front of and behind the optimal viewing location, begin to move away from each other with small changes in viewing distance. In the viewing geometry of FIG. 6B, for a display with the same-sized image zone 652, the beam bundle FOV 654 is significantly wider, allowing multiple viewers at different viewing distances to be within the viewing zone 656. In the case shown in FIG. 6B, the positional tolerance is large.

[0098] The viewing zone can be increased by increasing the FOV of each display beam bundle. This change can be made by increasing the width of the light emitter rows or by changing the focal length of the beam-collimating optics. Unfortunately, a smaller focal length can result in larger voxels. Therefore, for better resolution, the focal length can be increased. This situation generally means that there is a trade-off between optics design parameters and device size.

[0099] In some embodiments, to produce a 3D image with good resolution, each projected view beam is very well collimated and has a narrow diameter. If the beam diameter and divergence are large, the voxel will be perceived as a large spot by the retina of the eye. Voxels located behind the display surface are formed using a virtual extension of the emitted beam and can be larger because the eye's resolution becomes lower as the distance becomes greater.

[0100] For some embodiments, multiple viewers can view the display, such as a multi-view display. For some embodiments, the light field (LF) display structure can include a three-dimensional (3D) display, where the LF display structure includes a diffuser with directional controllability patterned across the 3D display, enabling spatially varying diffusion directional characteristics.

[0101] FIG. 7A illustrates an exemplary ideal case of perfect collimation without any beam divergence caused by one or more geometric factors, according to some embodiments. FIG. 7B illustrates an exemplary beam divergence caused by one or more geometric factors, according to some embodiments. FIG. 7C illustrates an exemplary beam divergence caused by one or more geometric factors, according to some embodiments. For the ideal lens of FIG. 7A, the achievable light beam collimation depends on two geometric factors: the size of the light source and the focal length of the lens. Perfect collimation 704 without any beam divergence can only be achieved in the theoretical case where a monochromatic point source (PS) 702 is placed exactly the focal length distance from an ideal positive lens. This case is depicted in FIG. 7A. Unfortunately, all real light sources have some surface area from which light is emitted, making them extended light sources (ES). Because each point of the source is imaged separately by the lens, the total beam will consist of a group of collimated sub-beams propagating in somewhat different directions after the lens. 7A-7C, as the source becomes larger, such as 712, 722, the total beam divergence 714, 724 increases. This geometric factor generally cannot be avoided by any optical means, and it is the dominant feature causing beam divergence when using relatively large light sources.

[0102] Another non-geometric feature that causes beam divergence is diffraction. This term refers to a variety of phenomena that occur when a wave (of light) encounters an obstacle or a slit. Diffraction is the bending of light around a geometric shadow area at the corner of an aperture. Diffraction effects can occur in all imaging systems and cannot be eliminated even with a perfect lens design that can cancel out all optical aberrations. Because most of the blur remaining in an image comes from diffraction, lenses that can achieve the highest optical quality are often called "diffraction-limited." The angular resolution achievable with a diffraction-limited lens can be calculated using the formula in Equation 1:

[0103]

number

[0104] where λ is the wavelength of the light and D is the diameter of the lens aperture. From the equation, we can see that only the color of the light (wavelength) and the lens aperture size (diameter of the light entering the viewer's pupil) have an effect on the amount of diffraction.

[0105] FIG. 7D illustrates an exemplary beam divergence caused by diffraction and a first aperture size, according to some embodiments. FIG. 7E illustrates an exemplary beam divergence caused by diffraction and a second aperture size, according to some embodiments. FIG. 7F illustrates an exemplary beam divergence caused by diffraction and a third aperture size, according to some embodiments. FIGS. 7D-7F show a schematic representation of how beam divergence 734, 744, 754 increases when lens aperture sizes 732, 742, 752 are reduced. This effect can actually be formulated into a general rule in imaging optical system design: if a design is diffraction-limited, the only way to improve resolution is to make the aperture larger. Diffraction is generally the dominant feature causing beam divergence when using relatively small light sources.

[0106] As shown in Figures 7A-7C, the size of the extended source has a large effect on the achievable beam divergence. The source geometry or spatial distribution is actually mapped to the angular distribution of the beam, and this property can be seen in the resulting "far-field image" of the source-lens system. In practice, this property means that when a collimating lens is positioned at a focal length from the source, the source is actually imaged at a relatively large distance from the lens, and the size of the image can be determined from the system "magnification." In the case of a single imaging lens, this magnification can be calculated by dividing the distance between the lens and the image by the distance between the source and the lens, as shown in Equation 2.

[0107]

number

[0108] Figure 8A illustrates an exemplary image magnifying lens having a first refractive power, according to some embodiments. Figure 8B illustrates an exemplary image magnifying lens having a second refractive power, according to some embodiments. Figure 8C illustrates an exemplary image magnifying lens having a third refractive power, according to some embodiments. Figures 8A-8C illustrate Equation 2 for three different lens-to-image distances 806, 836, 866, where increasing distances 806, 836, 866 result in larger images 808, 838, 868. When the distances 804, 834, 864 between the source and lens (with fixed heights 802, 832, 862) are fixed, different image distances can be achieved by varying the lens's refractive power using the lens curvature. However, as the image distance becomes larger and larger compared to the lens focal length, the change in lens power becomes smaller and smaller, approaching a situation where the lens effectively collimates the emitted light into a beam with the spatial distribution of the source mapped to the angular distribution, and an image of the source is formed without any focus adjustment.

[0109] In flat-form-factor goggle-less 3D displays, the display projection lens typically has a very small focal length to achieve a flat structure, and the beam from a single display optics cell is projected at a relatively large viewing distance. This means that as the beam of light propagates to the viewer, the source is effectively imaged with high magnification. For example, if the source size is 50 μm × 50 μm, the projection lens focal length is 1 mm, and the viewing distance is 1 m, the magnification is 1000:1, and the source geometric image is 50 mm × 50 mm. This means that within this 50 mm diameter eyebox, a single light emitter can be seen using only one eye.

[0110] For a lens with a magnification of 1000:1, if the source has a diameter of 100 μm, the resulting image will be 100 mm wide, and the same pixel may be visible to both eyes simultaneously, since the average distance between the pupils of the eyes is only 64 mm. In this latter case, a stereoscopic 3D image is not formed, since both eyes see the same image. This exemplary calculation shows how geometric parameters such as source size, lens focal length, and viewing distance are linked to each other.

[0111] Both geometric and diffractive effects work together, and LF display pixel designs can balance geometric and diffractive effects to achieve a particular voxel resolution. This is accentuated when using very small light sources, as optical system measurements get closer to the wavelength of light and diffractive effects begin to dominate performance. Figures 9A through 9D illustrate how geometric and diffractive effects work together for the cases of one and two extended sources imaged at a fixed distance with a fixed magnification. Figures 9A through 9D show the light source spot size for different geometric magnifications and diffractive effects.

[0112] FIG. 9A illustrates an exemplary first light source and lens configuration, according to some embodiments. For the exemplary configuration of FIG. 9A, an extended source (ES) 902 is positioned 10 cm focal length 904 from the magnifying lens. The light beam passing through the exemplary lens aperture 906 is spaced 5 cm apart. The light beam has a geometric image shown as GI 908. The light source has a diffraction image height shown by DI 910. FIG. 9A illustrates a relatively small lens aperture size, and the geometric image (GI) 908 is surrounded by blur due to diffraction, making the diffraction image (DI) 910 much larger.

[0113] FIG. 9B illustrates an exemplary second light source and lens configuration, according to some embodiments. For the exemplary configuration of FIG. 9B, two extended sources 922, 924 are positioned 10 cm from the magnifying lens at a focal length 926. The light beams passing through the exemplary lens aperture 928 are spaced 5 cm apart. The light beams generate respective images, indicated with heights GI1 (930) and GI2 (934), respectively. Each light source has a respective diffraction image height, indicated by DI1 (932) and DI2 (936), respectively. FIG. 9B illustrates the case where two extended sources are positioned side-by-side and imaged using the same small aperture lens. Even though the GIs of both sources are separated, the diffraction images overlap, making it impossible to resolve the two source images. In practice, this means that reducing the source size may not improve the achievable voxel resolution, since the resulting source image size may be the same when using two separate light sources as when using one larger source that covers the area of ​​both separate emitters. In order to resolve the two source images as separate pixels / voxels, the aperture size of the imaging lens may be increased.

[0114] FIG. 9C illustrates an exemplary third light source and lens configuration, according to some embodiments. For the exemplary configuration of FIG. 9C, an extended source (ES) 942 is positioned 10 cm focal length 944 from the magnifying lens. A light beam passing through an exemplary lens aperture 946 is spaced 10 cm apart. The light beam generates an image indicated with a height GI 948. The light source has a diffraction index indicated by DI 950. Compared to FIG. 9A, the distances GI 908, 948 are the same in both figures, but the diffraction image height 950 in FIG. 9C is smaller than the diffraction image height 910 in FIG. 9A. FIG. 9C shows the same focal length lens as FIGS. 9A and 9B, but a larger aperture 946 is used when imaging the extended source 942. Diffraction is reduced, and the diffraction image can be slightly larger than the geometric image, which remains the same size because the magnification is fixed.

[0115] FIG. 9D illustrates an exemplary fourth light source and lens configuration, according to some embodiments. For the exemplary configuration of FIG. 9D, two extended sources (962, 964) are positioned 10 cm from the magnifying lens at a focal length 966. The light beams passing through the exemplary lens aperture 968 are spaced 10 cm apart. The light beams generate respective images, indicated with heights GI1 (970) and GI2 (974), respectively. Each light source has a respective diffraction image height, indicated by DI1 (972) and DI2 (976), respectively. Compared to FIG. 9B, the distances GI1 (930, 970) and GI2 (934, 974) are the same in both figures, but the diffraction image heights (972, 976) in FIG. 9D are smaller than the diffraction image heights (932, 936) in FIG. 9B. In FIG. 9D, the diffraction images are non-overlapping and so the two spots can be resolved, thereby allowing the use of two different sources and improved spatial resolution of the voxel grid.

[0116] Non-Patent Document 1 discusses a new display technology based on the use of so-called μLEDs. MicroLEDs are LED chips typically fabricated from the same materials and using the same techniques as other LED chips used today. However, μLEDs are miniaturized versions of commonly available components, and μLEDs can be made as small as 1 μm to 10 μm. One challenge with μLEDs is how to handle such small components in display manufacturing. Non-Patent Document 2 discusses one of the densest matrices ever fabricated: 2 μm × 2 μm chips assembled on a 3 μm pitch. μLEDs have been used as backlighting components in TVs, but μLEDs are expected to challenge OLEDs in the μdisplay market in the near future. Compared to OLEDs, many μLEDs are more stable components and can produce higher light intensities, which allows them to be used in many applications, such as head-mounted display systems, adaptive automotive headlamps (as LED matrices), and TV backlights. μLEDs can also be used in 3D displays, which use a very dense matrix of individually addressable light emitters that can be switched on and off very quickly.

[0117] Bare μLED chips can emit specific colors with a spectral width of approximately 20–30 nm. White light sources can be produced by coating the chip with a layer of phosphor, which converts the light emitted by a blue or UV LED into a broader white light emission spectrum. Full-color sources can also be produced by arranging separate red, green, and blue LED chips side by side. The combination of these three primary colors can create the sensation of a full-color pixel when the separate color emissions are combined by the human visual system. A very dense matrix can enable the fabrication of self-emissive full-color pixels with a total width of less than 10 μm (3 × 3 μm pitch).

[0118] The light extraction efficiency from a semiconductor chip is a parameter that indicates the electrical-optical efficiency of an LED structure. Several methods exist that aim to increase the extraction efficiency and enable the construction of LED-based light sources that efficiently utilize electrical energy, such as in mobile devices with limited power sources. One method, presented in U.S. Patent No. 6,275,393, is understood to be based on the use of molded plastic optical elements integrated directly onto the LED chip. Due to the lower refractive index difference, the integration of the plastic shape extracts more light from the chip material compared to a chip surrounded by air. The plastic shape also enhances light extraction from the plastic piece and guides the light in a way that makes the radiation pattern more directional. Another method, presented in U.S. Patent No. 6,275,393, is understood to enhance light extraction from μLED chips. This is done by molding the chip in a shape that favors the light emission angle, which is more perpendicular to the front surface of the semiconductor chip and allows light to escape from the high-refractive-index material. These structures also guide the light emitted from the chip. In the latter case, the extraction efficiency is calculated to be twice as good as that of a typical μLED, and more light is emitted in a 30° emission cone compared to a typical chip with a Lambertian diffusion of the emitted light, which is uniformly distributed over the surrounding hemisphere.

[0119] Several components and systems based on liquid crystal (LC) materials have been developed for electrical control of light propagation, and such components are available in large quantities at lower cost. For some embodiments, LC-based tunable components can be used in 3D displays. Such LC components may be able to induce light beam adjustment without moving mechanical parts. LC-based components generally use linearly polarized light, which can reduce optical efficiency and increase power consumption. Because LCDs are generally polarization-dependent devices, light propagation control components can be used in 3D displays without the high cost of efficiency. Non-Patent Document 3 describes the use of cholesteric LCs (instead of more common nematic phase crystals) that can be used for polarization-independent beam steering, enabling increased component transmittance for, for example, OLED- or μLED-based display panels.

[0120] Patent Document 3 is understood to describe the use of LC components as electrically switchable parallax barriers in autostereoscopic 3D displays. When the LC layer is activated, a black grid structure blocks some display pixel view directions, allowing different images to be presented to the viewer's two eyes. Without an activated grid, the display functions as a regular 2D display. Patent Document 4 is understood to describe the use of an LC layer in forming a lenticular lens structure over a dense pixel matrix by reorienting some of the LC material molecules using an electric current. Although the LC layer can use a complex electrode design, it can also be used to switch between 2D and 3D modes so that the LC lenses project pixel images in different view directions. In the latter mode, only spatial multiplexing is used to generate a multi-view image, so multiple views can be obtained at the expense of spatial resolution. Non-Patent Document 4 discusses a proposed system in which electrically formed lenticular LC lenses are scanned across the display surface, adding the possibility of temporal multiplexing. In this case, pixels synchronized to the scanning action can be activated several times within a single scanning time frame, generating several additional views.

[0121] As a highly birefringent material, the LC layer has different refractive indices in two orthogonal directions. This property can be used, for example, with polymer microprisms to switch between two beam steering states using a structure containing two LC layers, according to [5]. The first, active LC layer is disposed, for example, between two glass sheets containing electrodes. The second, passive layer is formed between a glass or polymer substrate and a polymer microprism sheet. When a voltage is applied, the active LC layer rotates the linear polarization of the incident beam by 90° perpendicular to the propagation direction. This rotation selects which of the refractive indices of the birefringent passive LC layer is used in the second part of the device. In the first state of the steering device, the refractive index difference between the passive LC layer and the microprism polymer material is so small that no bending of light occurs. In the second state, the index difference causes the light beam to bend at a predetermined angle at the interface. This angle is usually quite small (around 1°), but the angle can be increased, for example, by adding a holographic diffraction grating after the LC layer (according to non-patent document 7) or by stacking several polarization-based beam steering components, as understood according to patent document 5, making it possible to reach angles as large as ±15°, for example.

[0122] Patent document 6 is understood to describe a hybrid system in which a light beam-tuning LC element is used in front of a rigid polymer lenticular sheet structure, while non-patent document 7 uses an LC element after the rigid polymer lenticular sheet structure to enable the generation of additional angular view directions between the pixel positions and the directions determined by the lenticular optics. In these cases, temporal multiplexing is used together with spatial multiplexing in a 3D multi-view display. The same LC-based beam steering screen component can also be used in a similar manner with multiple projectors, according to non-patent document 8.

[0123] In addition to beam angle steering, it is understood that LC-based components with hybrid structures (as understood to be described in Patent Documents 7, 8, and 9) can be used to adjust beam focus without mechanical movement. This electronic focus adjustment can be utilized in head-mounted devices that can move the virtual image of a stereoscopic 3D display to a different focal distance from the eyes to make the image appear more natural, according to Non-Patent Document 9. Beam focus adjustment can also be utilized in goggle-less 3D displays by adjusting the position or shape of the projected image focal plane, according to Non-Patent Document 10. For example, in many of the cases described in exemplary 3D / LF display patents or papers, focus adjustment directly changes the entire projected image. For example, Non-Patent Document 11 describes an exemplary lens system including an array of focus-adjustable microlenses.

[0124] FIG. 10 illustrates an exemplary variable focal length microlens array, according to some embodiments. Figure 10 illustrates the structure and function of a varifocal microlens. An LC layer 1004 is disposed between a glass substrate 1006 and a microlens array (MLA) 1002. Both interfacial material interfaces have transparent, conductive indium tin oxide (ITO) pattern coatings 1010, 1012, which serve as anodes and cathodes for active adjustment of the LC layer. When a voltage is applied, the electric field rotates the LC molecules, and the refractive index of the material changes in the linear polarization direction. For some embodiments, using a nematic liquid crystal material and a low voltage in the range of 0 to 12 V, the amount of index change is on the order of approximately 0.2. For some embodiments, the refractive index of the LC material (approximately 1.5) is set to be close to that of the MLA material.

[0125] Figure 10 shows three example beams of collimated light 1016 that initially strike a polarizer component 1008, which transmits only linearly polarized light. By adjusting the refractive index of the LC layer with an applied voltage, the beam can be made to focus into a converging beam 1020, diverge as a diverging beam 1024, or remain unchanged as a collimated beam 1022. If the index of the LC is adjusted to match that of the MLA, the interface disappears and beam collimation is unaffected. If the index is adjusted below or above the index value of the MLA, the beam is refracted, and a real focal point 1018 or virtual focal point 1014 is created in front of or behind the structure.

[0126] When a voltage is applied to the LC material, the crystals align in a specific direction dictated by the electric field generated on the LC material layer. In the absence of a voltage, the crystals can be randomly oriented or in some other ordered orientation created by preparing the material using different techniques. The voltage level affects the amount of orientation and can be used to tune the optical properties of the material. If electrodes on both sides of the LC material layer are patterned in such a way that the local electric field can be adjusted, the local crystal orientation within an otherwise homogeneous LC layer can be adjusted. With the appropriate electrode design, gradual adjustment of the electric field over an area on the LC layer can be used to adjust the refractive index, creating, for example, LC microlenses.

[0127] For some embodiments, the angle of diffusion can be changed when the viewer's eyes are tracked. For some embodiments, when the angle of diffusion is changed, the light emission intensity of the μLEDs can be increased, for example, to compensate for the greater spread of light and maintain the same irradiance at a point within the viewing window. For some embodiments, when the angle of diffusion is changed, the number of light sources can be increased or decreased, for example.

[0128] Figure 10 is a schematic diagram of a focus-tunable microlens based on LC material. The basic idea is to locally tune the electric field at three different microlens shapes fixed within other boundary layers around the LC material layer. In the top case, the LC refractive index is tuned (by orienting the liquid crystals) to be smaller than that of the lens material, and the collimated beam is focused to a point. In the depicted middle case, the LC material has the same refractive index as the microlens, eliminating the optical interface and allowing the light to pass through with no change to collimation. In the presented bottom case, the LC material refractive index is tuned to a higher value than the lens material, essentially creating a negative focal length lens that diverges the incoming beam. Non-Patent Document 12 discusses this idea in more detail.

[0129] Non-Patent Document 13 describes the use of liquid crystal materials in switchable or tunable diffraction gratings. Liquid crystal materials can also be used in diffusers. Switchable diffraction gratings are used to split a light beam into multiple child beams propagating in different directions according to the diffraction grating formula, whose main optical parameter is the grating period. This parameter can be influenced by the LC diffraction grating electrode design, which needs to be sophisticated enough to induce the required high-density variable refractive index pattern in the LC material. Tunable diffusers are used to scatter light; they are typically electrically switchable between transparent and translucent states. These components are based on the electrical tuning of LC materials, which are modified to perform specific changes under an applied electric field.

[0130] Non-Patent Document 14 describes an LC diffuser based on a polymer-stabilized cholesteric texture (PSCT) approach. In these components, the transparent / scattering material was prepared in such a way that the texture contained a liquid crystal material. According to Non-Patent Documents 15 and 16, another tunable diffuser type uses polymer-stabilized liquid crystals (PSLCs) with micrometer-sized LC droplets embedded in an optically transparent polymer matrix with a matched refractive index. When an electric field is applied to the PSLC material, the refractive index of the aligned droplets is changed, and the interface between the droplets and the surrounding polymer begins to refract light. This means that when the tunable diffuser is activated, light is scattered in all directions from the small LC particles embedded inside the material. For such material-based scattering, the light diffusion effect tends to be large, but because a large portion of the light is scattered back, the transmission through the component tends to be reduced and there is little control over the angular distribution of the scattered light.

[0131] Several hybrid LC diffuser optical structures have been developed. U.S. Patent No. 6,277,693 is understood to describe combining a switchable LC diffuser layer with a light-diffusing surface structure. The diffusing surface can be a separately manufactured foil, possibly laminated to an adjustable portion, or the diffusing surface can be an integrated structure patterned directly on the outer surface of the LC diffuser. The diffusing properties of the static diffusing surface can be increased or decreased by switching an adjustable diffuser on or off. U.S. Patent No. 6,277,693 (now U.S. Patent No. 6,277,693) is understood to describe a hybrid structure in which a combination of lenticular microlenses and an LC diffuser layer is used to switch an autostereoscopic display between 2D and 3D display modes. This switching is achieved by diffusing the angular distribution of the multi-view display by switching on the LC diffuser. U.S. Patent No. 6,277,693 is also understood to describe switching between 2D and 3D display modes. Electrically tunable LC diffusers that can be switched between transparent and translucent states have been widely used, for example, in volumetric displays based on sequential image projection onto multiple switchable screens, as described in U.S. Patent Nos. 5,629,999 and 5,729,999. Such components scatter light uniformly in all directions. This feature can be useful when the components are used in volumetric displays, where voxels are visible from all directions. However, such volumetric 3D images cannot properly handle occlusions, making them appear translucent and somewhat unnatural.

[0132] There are several methods for creating light-diffusing components. Light-scattering structures can be based on, for example, material internal scattering, diffraction, or surface scattering. Diffraction and surface scattering methods can be used to create surface structures that generate specific angular light distributions. For many material-based diffusion methods, the structures are more difficult to fabricate because the light-scattering particles are suspended in some medium or the material has a fixed internal structure that scatters the light.

[0133] Patent Document 16, now Patent Document 17, is understood to describe a surface scattering-based diffuser. These light-shaping diffusers (LSDs) use surface relief structures replicated from a holographically recorded master. These pseudo-random, non-periodic structures can diffuse light into some very specific angular distribution. This diffusion pattern can be designed by creating microstructures with specific gradient distributions that manipulate the incoming light and change its direction on a very small scale. Such structures can be used for precise diffusion angle control and efficient light transmission through components, since no light is wasted due to backscattering.

[0134] For some embodiments, the optical image display structure can include an adjustable light diffusing component. Some embodiments of the method can include diffusing light using the adjustable light diffusing component. For some embodiments, the optical image display structure can include a 3D multi-view display device. Some embodiments of the method can include displaying a multi-view 3D image using the 3D multi-view display device. For some embodiments, the adjustable light diffusing component can be a surface effect liquid crystal (SELC) diffuser. The diffuser can be an angle-selective diffusing component that can be activated without mechanical movement. SELC diffusers scatter light from optical interfaces, which can exist, for example, between a birefringent material and a substrate material with very small-scale surface features. The liquid crystal material of the SELC diffuser is used to change the light polarization direction or the material refractive index, which transmits or scatters light beams at the designed interfaces. Some material-based diffusers (such as polymer-dispersed liquid crystal (PDLC) and polymer-stabilized cholesteric texture (PSCT)) may produce the same light distribution in both the vertical and horizontal directions due to internal material scattering. The use of optical interface scattering can enable higher transmission efficiency and enable the use of components in 3D displays whose scattering properties can be selectively tuned for specific light propagation directions.

[0135] SELC diffusers can be used in many different types of 3D displays, improving functionality and / or performance over other structures. In addition to 3D displays, SELC diffusers can be used, for example, to control lighting patterns generated using LED lamps. SELC diffusers can be electronically adjusted to diffuse light evenly over a wide area or to project a spotlight. SELC diffusers can be used, for example, in security / privacy glass windows that can be switched between a transparent mode (allowing light to pass through the glass window) and a translucent mode (blocking light from passing through the glass window). Further examples of uses for SELC diffusers include optical measurement devices that use specific, adjustable lighting patterns, photographic effects that can create an artificial bokeh effect across a lens aperture, and optical communications modules that can use an adjustable diffuser as a switch between light channels.

[0136] For some embodiments, light is generated on a layer containing individually addressable pixels, which can form, for example, a μLED matrix. A microlens array (MLA) can be used to collimate the emitted light into multiple beams that are used to create multiple views in either the horizontal or vertical direction. A SELC diffuser positioned between the light-emitting device and the MLA can be used to selectively diffuse the light beam in two orthogonal directions to increase the image FOV and enable the use of the display structure in mobile devices, which can be handheld. A polarizer sheet positioned between the emitter and the diffuser can be used to linearly polarize the emitted light.

[0137] For some embodiments, the polarizer can be laminated as a foil, for example, on the MLA or on the first substrate of the SELC diffuser, making the structure more compact and robust. The use of a cross-shaped patterned source and microlenses instead of a lenticular sheet allows for rotation of the multi-view image orientation. Such a feature can be used by mobile devices when the display mode is changed from portrait to landscape.

[0138] Electrically controlled diffuser components can be used for light redirection without moving parts and typically with thin optical layers. The use of optical interface scattering allows for the use of components whose scattering properties can be selectively tuned for different light propagation directions, unlike many material-based diffusers that produce the same light distribution for both horizontal and vertical directions, for example.

[0139] For some embodiments, the diffuser's diffusing surface features can be created as a uniform structure across the entire interface, or can be arranged in different array patterns with specific local characteristics. See Figures 10 and 11A for examples of such diffuser patterns. When a uniform distribution across the surface is used, the electrode design can be simple and achieve uniform optical functionality across the diffuser's optical aperture.

[0140] SELC diffusers can be used as adjustable diffuser components with several different types of 3D displays, such as those described in U.S. Patent No. 6,275,299, as well as U.S. Patent No. 6,275,299 and U.S. Patent No. 6,275,299 and U.S. Patent No. 6,275,299. SELC diffusers can be used to eliminate the "picket fence" effect in 2D displays by gradually reducing pixel spacing, which can be used with head-mounted VR / AR / MR devices. The ability to adjust diffusion allows for a delicate balance between image uniformity and resolution. Because SELC diffusers can be used to make small alignment adjustments, the use of SELC diffusers enables the use of multi-view 3D displays without ultra-precise alignment of two optical layers. For some embodiments, an active diffuser control device can perform an on / off function to activate the diffuser when the display mode changes, which can have very low switching speed requirements. When different color light emitters in a display are arranged using a corresponding layout, the SELC diffuser may be able to diffuse the different color emissions together in the viewing window, thereby reducing (or, for some embodiments, eliminating) optical- or rendering-based methods for color synthesis. SELC diffusers can be used with mobile devices to switch between portrait and landscape modes. Such features can be used to reduce associated components, such as image processing (which may include image rendering) and light-emitting components. Fewer emitter components require fewer electrical contacts to the small light-emitting μLEDs, allowing for less control electronics. Furthermore, a cross-shaped source pattern can allow more space on the source module subassembly for electrical wiring and controller components.

[0141] For some embodiments, a surface-effect liquid crystal (SELC) diffuser can be used as an electrically tunable optical component capable of angle-selective light diffusion. For some embodiments, light can be scattered by an optical interface disposed between a birefringent material and a substrate material with very small-scale surface features. For some embodiments, a liquid crystal material can be used to change the light polarization direction and / or material refractive index, which can cause the light beam to be transmitted or scattered at the interface. The use of optical interface scattering can enable higher transmission efficiency and enable the use of components in 3D displays that can selectively tune scattering properties for different light propagation directions. Some material-based diffusers (such as polymer-dispersed liquid crystal (PDLC) and polymer-stabilized cholesteric texture (PSCT)) can generate the same light distribution in both vertical and horizontal directions due to material internal scattering.

[0142] FIG. 11A illustrates an exemplary two-component SELC diffuser in a light beam transmitting state, according to some embodiments. FIG. 11B illustrates an exemplary two-component SELC diffuser in a light beam diffusing state, according to some embodiments. FIGS. 11A and 11B illustrate an exemplary electrically tunable optical component, referred to as a surface effect liquid crystal (SELC) diffuser structure, and its functionality. The exemplary structure has two optical subcomponents, one active and one passive. The active subcomponent can be a thin layer of LC material 1104, 1154 used to selectively rotate the polarization of light, disposed between two substrates 1102, 1106, 1152, 1156, which can be, for example, glass or polymer foils. Both substrates 1102, 1106, 1152, 1156 can have transparent indium tin oxide (ITO) coatings 1108, 1110, 1158, 1160 and electrodes. The first subcomponent can be used as a tunable retarder to rotate the polarization direction of linearly polarized light 1120, 1170 by 90°. This can be achieved using a voltage applied to electrodes that generates an electric field across the LC material 1104, 1154. Polarization rotation can be activated by switching the voltage on or off. The second passive subcomponent can have two or more materials, one of which can be highly birefringent 1114, 1164, and the materials can be connected to each other using a common optical interface. The internal structure orientation and refractive index of the birefringent material can be matched to the non-birefringent material 1112, 1162 in such a way that in one incident light polarization direction, the refractive index is the same, allowing a collimated beam 1118 to be transmitted, while in the orthogonal direction, there is a difference that causes light refraction and the generation of a divergent beam with a designed divergence angle 1168. This interface can have a surface microstructure with a designed gradient distribution. The structures can be unidirectional or bidirectional, with a particular sense of rotation for the two optical axes of the birefringent material.For some embodiments, the second passive subcomponent can consist of a birefringent / non-birefringent material interface with engineered surface features that are used to selectively transmit or diffuse a light beam based on its polarization. For some embodiments, the surface can be patterned into subregions (not shown).

[0143] For a particular light polarization direction, the refractive index of the birefringent material of the passive subcomponent can be the same as that of the non-birefringent material, so the interface between these two materials can be transparent, allowing a light beam with the correct linear polarization orientation to pass through without scattering. However, if the beam polarization direction is rotated, the refractive index of the birefringent material can be different, and the index difference between the two materials can appear at the interface. For some embodiments, surface microstructures can become visible, allowing light to be refracted from small surface features. In the tunable SELC diffuser structure shown in FIG. 11A, a linearly polarized beam passes through the active component unaltered, and the beam strikes the structured interface of the second passive component in an orientation where there is no index difference between the birefringent material and the second substrate. In this case, the beam is transmitted. FIG. 11B shows the case where a voltage is applied to the active component, rotating the beam polarization direction by 90°. In this second case, the rotated beam experiences different refractive indices within the birefringent material of the passive subcomponent, and the surface structured interfaces become visible and scatter the beam.

[0144] For some embodiments, the exemplary device may include a diffuser configured to change the direction of diffusion of the light beam upon application of a voltage to the diffuser. For some embodiments, the exemplary device may further include a light field display structure configured to generate one or more collimated light beams incident on the diffuser. For some embodiments, a method of using the exemplary device may include changing the direction of diffusion of the light beam upon application of a voltage to the diffuser.

[0145] For some embodiments, a further exemplary device can include a liquid crystal grating configured to spread a light beam into two or more spread light beams. For some embodiments, a method of using the further exemplary device can include spreading a light beam into two or more spread light beams upon application of a voltage to the liquid crystal grating.

[0146] For some embodiments, the multi-view three-dimensional optical display can include a selective direction diffuser configured to be selectively activated without mechanical movement, the angle-selective diffuser comprising at least one surface-effect liquid crystal (SELC) diffuser configured to receive one or more linearly polarized and collimated beams of light and diffuse them in selective directions in response to an applied electric field.

[0147] Some embodiments of a light field (LF) display device can include an SELC diffuser including a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, where at least one of the LC material layer and the first and second substrates is configured to perform angle-selective diffusion of light, as in the example shown in Figures 11A and 11B. For some embodiments, the optical element can include a first layer comprising electrically tunable liquid crystals capable of changing the polarization state of light passing through the first layer depending on the state of electrical tuning, and a second layer comprising a birefringent material in a layer parallel to the first layer, the second layer including a surface structure designed to impart alternating diffusion properties to the beam, where the second layer is configured to scatter light incident on the second layer according to a first angular pattern when the polarization state of the light is in a first polarization state, and the second layer is configured to scatter light incident on the second layer according to a second angular pattern when the polarization state of the light is in a second polarization state.

[0148] For some embodiments, an LF display device can perform a process including emitting a light beam from one or more light-emitting devices, polarizing the light beam into a linearly polarized beam, passing the light beam through a liquid crystal (LC) material, passing the light beam through a birefringent material, and applying a voltage to the LC material to change the light polarization configuration state of the LC material, where changing the light polarization configuration state switches from a first polarization state to a second polarization state, the first polarization state diffusing the light beam in a first direction upon passing through the birefringent material, and the second polarization state diffusing the light beam in a second direction upon passing through the birefringent material. For some embodiments, an SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, where the LC material layer is configured to cooperate with the first substrate and the second substrate to cause angle-selective diffusion of light in response to an applied voltage. Examples of such operation are shown in Figures 11A and 11B.

[0149] Figure 12A illustrates an exemplary single-component SELC diffuser in a light beam transmitting state, according to some embodiments. Figure 12B illustrates an exemplary single-component SELC diffuser in a light beam diffusing state, according to some embodiments. Figures 12A and 12B illustrate exemplary optical structures and functionality of SELC diffusers 1212, 1262. In this structure, a single active component is used to switch light diffusion on or off, causing linearly polarized and collimated beams of light 1266, 1216 to become divergent beams 1264 with a designed divergence angle or transmitted collimated beams 1214, respectively. For some embodiments, layers of liquid crystal material 1204, 1254 can be disposed between thin glass substrates 1202, 1252 and second substrates 1206, 1256 with small optical surface features. The refractive index of the liquid crystal material 1204, 1254 can be tuned to match the index of the material of the second substrate. For example, nematic liquid crystals can have a refractive index of approximately 1.5, close to the refractive index of 1.49 for polymethylmethacrylate (PMMA) optical polymer material. As shown in Figures 12A and 12B, transparent ITO electrodes can be coated on both sides of the LC material 1204, 1254 using ITO coatings 1208, 1210, 1258, and 1260. For some embodiments, the ITO electrodes can be large, as they may be used to uniformly tune the refractive index of the LC material across the entire surface area. For some embodiments, the electrodes can be fabricated with fine patterns that support local modulation of the material refractive index over some portions of the surface. These patterns can be, for example, asymmetric hole-pattern electrodes that generate a non-uniform electric field that modifies the material refractive index over a non-uniform LC material thickness. The electrodes can be patterned, for example, onto the fine optical features or applied separately onto the flat side of a thin substrate layer (e.g., a polymer foil) used in the fabrication of the optical features.Fabrication of the electrodes and optical features can be done using roll-to-roll processing, which can allow for large surface area coverage and lower costs to be achieved when large volumes are used.

[0150] In the example component structure of the SELC diffuser 1262 shown in FIG. 12B , the surface microstructure between the LC material 1254 and the second substrate 1256 is unidirectional, meaning that the shape forms straight grooves in one direction. An electric field on the LC layer can be used to tune the refractive index of the LC material. When the index of the material is the same as the refractive index of the second substrate, light can be transmitted. When a voltage is applied and the refractive index of the LC material is tuned to a higher value, the structured surface can become visible and the light can be scattered in one direction. As a result, by applying a voltage on the LC material, a well-collimated beam can be changed to a beam that is diffused in one direction but remains collimated in the other direction, as shown in FIG. 12B .

[0151] Figure 13A illustrates an exemplary SELC diffuser with a smaller divergence angle, according to some embodiments. Figure 13B illustrates an exemplary SELC diffuser with a larger divergence angle, according to some embodiments. In Figure 13A, no voltage is applied to the LC material 1304 sandwiched between the first substrate 1302 and the second substrate 1306 in the diffuser, and a beam 1310 with a small divergence angle is generated from the beam 1308 of linearly polarized and collimated light. In Figure 13B, a voltage is applied to the LC material 1354 sandwiched between the first substrate 1352 and the second substrate 1356 in the diffuser, and a beam 1360 with a large divergence angle is generated from the beam 1358 of linearly polarized and collimated light.

[0152] For some embodiments, the device can include a diffuser configured to change an angle of divergence of the light beam upon application of a voltage to the diffuser. For some embodiments, a method performed by the device can include changing an angle of divergence of the light beam upon application of a voltage to the diffuser.

[0153] Figure 14A illustrates an exemplary SELC diffuser that allows horizontal diffusion, according to some embodiments. Figure 14B illustrates an exemplary SELC diffuser that allows vertical diffusion, according to some embodiments. For some embodiments, a single SELC diffuser component can have two or more light-diffusing surface structures. In one exemplary component structure, liquid crystal material 1404, 1454 is disposed between substrates 1402, 1406, 1452, 1456 of two different materials, both of which have slightly different refractive indices that can be reached using the tuning range of the LC material's refractive index. For example, if the refractive index of the LC material can be tuned over a range of 0.02, optical polymer materials (e.g., Zeonex 330R and Zeonex E48R) can be used as the two substrates 1402, 1406, 1452, 1456 because they have refractive indices of 1.51 and 1.53, respectively, at a light wavelength of 589 nm. With such a material, when the index of the LC material is adjusted to a value of 1.51, the interface of the first substrate is transparent, while the interface of the second substrate has a refractive index difference of 0.02. The situation is reversed when the LC refractive index is adjusted to 1.53 by applying a voltage to electrodes patterned on the two substrates. Such a diffuser with two different microstructures can be used as an angle-selective tunable diffuser. When the first interface has a different gradient profile than the second, some embodiments can make the divergence of the diffused beam smaller or larger by applying a voltage to the components, as shown, for example, in Figures 13A and 13B. Figures 14A and 14B show two orthogonal linear microstructures used to switch the direction of diffusion of linearly polarized and collimated beams 1408, 1458 from horizontal diffusion 1410 of ray 1412 to vertical diffusion 1460 of ray 1462 by applying a voltage to the LC material for some embodiments.

[0154] Some embodiments of the LF display structure can include two controllable diffusers, one or more of which are configured to be selectively activated without mechanical movement. One or more of the diffusers can be configured to diffuse light in response to an applied electric field. For some embodiments of LF displays having two layers of diffusers, the second layer can be configured to diffuse light horizontally when the polarization state of the light is in a first polarization state, and the second layer can be configured to diffuse light vertically when the polarization state of the light is in a second polarization state. Figures 14A and 14B show examples of switching from the first polarization state in Figure 14A to the second polarization state in Figure 14B. For some embodiments, the LF display structure can include a plurality of light-emitting elements and collimating microlenses capable of generating a collimated beam of light, and a direction-controllable diffuser capable of switching between a first state in which light is diffused in a first direction and a second state in which light is diffused in a second direction.

[0155] Light-scattering optical surface features can be manufactured, for example, as polycarbonate sheets with optical shapes made from UV-curable materials in a roll-to-roll process, or as foils with embossed structures. The surface shapes used can be flat, have angled facets (prisms), or continuously curved surfaces with different curvatures in two directions. For example, when unidirectional surface features similar to lenticular microlenses are used, components can be used to adjust the light-scattering properties separately in two orthogonal directions, as shown in the examples of Figures 11A and 11B. These structures can also be manufactured by very large-scale extrusion processes. The size and pattern fill factor of individual optical features can have an impact on the achievable beam divergence modulation and the amount of stray light introduced into the system, which reduces image contrast. This means that high-quality optical system manufacturing methods can be used to produce masters that are replicated for mass production.

[0156] One fabrication method for producing diffusive surface microstructures is composite holographic diffuser replication. Light-shaping diffuser (LSD) structures can have fine-tuned surface gradient distributions that can modify the angular distribution of a collimated beam, for example, to create linear, elliptical, or rectangular illumination patterns. The beam intensity profile can be modified, for example, to a "top-hat" pattern for higher spatial uniformity of the projected single beam, or to a Gaussian beam for higher illumination uniformity of the combined beam bundle.

[0157] For some embodiments, the diffuser's diffusing surface features can be created as a uniform structure across the entire interface, or can be arranged in different array patterns with specific local characteristics. If a uniform distribution across the surface is used, electrode design can be simple and achieve uniform optical functionality across the diffuser's optical aperture. If local variations are introduced into the microstructure and / or electrode design, variations in light modulation can be created within the component's optical aperture. This can be achieved, for example, by creating an interlaced matrix of adjustable diffuser squares that provide different modifications to the incident beam divergence in two orthogonal directions. Such a device can enable separate control over sections of the light beam, allowing for tuning of the internal structure of a single beam along with other possible optical features arranged in a mosaic pattern.

[0158] SELC diffusers can selectively adjust the light beam divergence in different angular directions. Many material-based scattering diffusers simultaneously change the beam divergence in all directions. Electrically controlled angle-selective diffusion can be used with 3D displays, using fine control over multiple beams. Integrated image-based multi-view displays or light-field displays can use multiple interlaced beams together to generate multiple distinct images with spatial and angular domains. Optical diffusing surfaces can be used to meet viewing and image uniformity requirements with optical display structures. For example, adjustable diffuser structures can be used to improve single-image uniformity, calibrate image characteristics for different viewing distances, generate volumetric images, create smoother transitions between neighboring views, rotate a mobile device display, or achieve image parallax in two directions.

[0159] For example, LF displays implementing SELC diffusers can be used in many different types of displays, such as HMDs, volumetric 3D displays, and screen-based 3D displays. In some embodiments, an example LF display can be considered or described as a holographic display. SELC diffusers can be used in many different types of 3D displays and can provide improved functionality and / or performance over other structures. In addition to 3D displays, SELC diffusers can be used, for example, to control lighting patterns generated using LED lamps. SELC diffusers can be electronically adjusted to diffuse light evenly over a large area or to project a spotlight. The shape of the spotlight can be adjusted to be circular or elliptical in two different directions, and this adjustment can be made without any mechanical movement. SELC diffusers can be used, for example, in security / privacy glass windows that can be switched between a transparent mode (allowing light to pass through the glass window) and a translucent mode (blocking light from passing through the glass window). Further examples of uses for SELC diffusers include optical measurement devices that use specific tunable illumination patterns, photographic effects that can create artificial bokeh effects across a lens aperture, and optical communications modules that can use tunable diffusers as switches between optical channels.

[0160] For some embodiments, a light beam can be emitted from a light-emitting device, and the horizontal divergence of the light beam can be changed by changing a horizontal light diffusion parameter (or, equivalently, a vertical light diffusion parameter), such as the horizontal (or vertical) size of an aperture, the full-width-at-half-maximum (FWHM) value of the light scattering distribution pattern in angular coordinate, or the voltage value used by the control electronics to achieve a particular FWHM scattering value. For some embodiments, the full-width-at-half-maximum (FWHM) value of the light scattering distribution pattern in angular coordinate can describe the optical functionality of a component. For some embodiments, the voltage value used by the control electronics to achieve a particular FWHM scattering value can describe a device system-level control value.

[0161] For some embodiments, the horizontal light diffusion parameter can include a setting for whether to apply a voltage to the LC material that is part of the diffuser, as in the examples shown in Figures 13A and 13B. For some embodiments, the horizontal diffusion parameter can set a control voltage applied to the horizontal SELC diffuser and LC grating layer, as shown in Figure 21, or the horizontal diffusion parameter can set a target amount of diffusion in the horizontal direction produced by the horizontal SELC diffuser and LC grating layer. For some embodiments, the horizontal diffusion parameter can indicate the amount of voltage to apply to the horizontal SELC diffuser and LC grating layer.

[0162] For some embodiments, a light beam can be emitted from a light-emitting device, and the vertical diffusion spread of the light beam can be changed by changing a vertical light diffusion parameter, such as the vertical size of an aperture. For some embodiments, the vertical light diffusion parameter can include a setting for whether to apply a voltage to an LC material that is part of the diffuser, as in the examples shown in FIGS. 13A and 13B. For some embodiments, the vertical diffusion parameter can set a control voltage applied to the vertical SELC diffuser and LC grating layer, as shown in FIG. 21, or the vertical diffusion parameter can set a target amount of diffusion in the vertical direction generated by the vertical SELC diffuser and LC grating layer. For some embodiments, the vertical diffusion parameter can indicate the amount of voltage applied to the vertical SELC diffuser and LC grating layer.

[0163] For some embodiments, the diffuser can be configured to switch the light emitted by the light-emitting device from diffusing in a horizontal direction to diffusing in a vertical direction. For some embodiments, the diffuser can be configured to switch the light emitted by the light-emitting device from diffusing in a vertical direction to diffusing in a horizontal direction.

[0164] For some embodiments, the exemplary device may include a diffuser configured to change the shape of a light beam upon application of a voltage to the diffuser. For some embodiments, the method performed by the exemplary device may include changing the shape of the light beam upon application of a voltage to the diffuser. For some embodiments, the exemplary device may include a diffuser configured to change the direction of the light beam upon application of a voltage to the diffuser. For some embodiments, the method performed by the exemplary device may include changing the direction of the light beam upon application of a voltage to the diffuser. For some embodiments, the exemplary device may include a diffuser configured to diffuse light in a single coordinate plane. For some embodiments, the method performed by the exemplary device may include diffusing light in the single coordinate plane. For some embodiments, the exemplary device may include a diffuser configured to receive a selection selected from the group consisting of a horizontal plane and a vertical plane and to diffuse light only in the selected plane. For some embodiments, the method performed by the exemplary device may include receiving a selection selected from the group consisting of a horizontal plane and a vertical plane and diffusing light only in the selected plane.

[0165] FIG. 15 illustrates an exemplary 3D light field optical display structure, according to some embodiments. For some embodiments, the multi-view 3D display structure can include an SELC diffuser. The 3D display can use an angle-selective diffusing component (e.g., an SELC diffuser) that can be activated without mechanical movement. FIG. 15 schematically illustrates an optical display structure and its functionality. Light can be generated on a layer 1502 containing individually addressable pixels. A single active emitter 1510 can be used to generate a single-beam FOV 1514. Multiple active emitters 1512 can be used to generate a multiple-beam FOV 1516. The light-emitting component can be, for example, a μLED matrix, an OLED display, or an LCD display with a backlight. A microlens array (MLA) 1506 can be used to collimate the emitted light into multiple beams used in generating multiple views in either the horizontal or vertical direction. An SELC diffuser 1508 positioned in front of the MLA 1506 can be used for selective diffusion of the view light beam in two orthogonal directions. Exemplary adjustable diffuser structures are described in more detail in connection with FIGS. 12A and 12B . To linearly polarize the light, a polarizer sheet 1504 can be positioned between the emitter attached to the light-emitting layer 1502 and the MLA 1506. For some embodiments, the polarizer 1504 can be laminated, for example, as a foil onto the MLA 1506 or onto the first substrate of the SELC diffuser 1508, making the structure more compact and robust. For some embodiments, the light-collimating structure can be a bidirectional microlens, which can be fabricated, for example, as a hot-embossed polymer sheet.

[0166] FIG. 16A illustrates an exemplary light emitter matrix layout for a full-color image using four subpixels for each full-color beam, according to some embodiments. FIG. 16B illustrates an exemplary light emitter matrix layout for a full-color image using three subpixels for each full-color beam, according to some embodiments. FIGS. 16A and 16B each illustrate an example of a light emitter pattern that can be used with a display optical structure for some embodiments. Both patterns have an exemplary cross-shaped layout in which μLEDs of different colors can be arranged in horizontal and vertical arrays. These two array directions can be used to create view beams in two orthogonal directions. With FIG. 16A, the full-color pixel includes one red, one green, one blue, and one white emitter, while with FIG. 16B, the layout includes only three different colors. The white emitter can be used with high dynamic range (HDR) images, for example, by using additional white light emission to enhance some image highlights. The white component can be created, for example, by coating a UV or blue μLED chip with a phosphor coating. Red, green, and blue can be created by converting the emission of the UV or blue chip using quantum dot (QD) coatings for specific light emission spectra. For some embodiments, pixels 1602, 1604, 1652, 1654 can include a set of one or more light-emitting devices 1606, 1608, 1610, 1656, 1658, 1660. For some embodiments, in pixels 1602, 1604 including red 1606, blue 1610, green 1608, and white light-emitting devices, the light-emitting devices can be arranged in a 2x2 square arrangement, such as the example shown in FIG. 16A. For some embodiments, in pixels including red, blue, green, and white light-emitting devices, the light-emitting devices can be arranged in a 1x4 line arrangement.For some embodiments, for example, horizontal resolution can be increased by varying the grouping of light-emitting elements in such a way that a first group of four subpixels starting with a red subpixel is used, and then the next group of four subpixels starting with a white subpixel is activated. Such an exemplary method, according to some embodiments, allows for better angular resolution for 3D images because full-color pixel position shifts can be performed at intervals of half a full-color pixel width. For some embodiments, the light-emitting elements can be configured in a plus-shaped pattern, such as the example shown in FIGS. 16A and 16B. For example, one or more rows can be configured to emit light horizontally, and one or more columns can be configured to emit light vertically. Some embodiments of LF display structures can include sets of light-emitting elements arranged in a plus-shaped pattern or a cross-shaped pattern, such as the example shown in FIGS. 16A and 16B.

[0167] FIG. 17 is a schematic perspective view illustrating an exemplary 3D display in portrait and landscape modes, according to some embodiments. The exemplary optical display structure can project multiple view beams from each display projector cell segmented by microlens apertures. For some embodiments, views can be generated in either the horizontal or vertical direction, but not both directions simultaneously. A stereoscopic effect can be generated by projecting two different images, one to each eye, at any given time. For some embodiments, a first image can be projected to one eye in the horizontal viewing direction, and a second image can be projected to the other eye in the horizontal viewing direction. For some embodiments, in 3D display applications, the display may be capable of multiple views. During portrait mode, multiple horizontal views 1702 can exist, but to conserve power, different vertical views may not be rendered and vertical elements may not be addressed. A SELC diffuser can spread a common view vertically. When the display is rotated, the diffusion can be switched to orthogonal directions, if applicable, to create multiple views in landscape mode 1704 or multiple views in portrait mode 1702, and active / idle display elements can be swapped. For some embodiments, other applications of addressable angle control of diffusion can be used. In FIG. 17, arrows indicate different view directions. To aid clarity, light rays are not depicted in FIG. 17. For example, on the left side of FIG. 17, light rays spread vertically, indicating vertical diffusion, but the view directions are from different angles in the horizontal plane, as shown.

[0168] For some embodiments, only eye convergence is used for 3D perception, so the view projection direction is the same as the direction determined by the viewer's two eyes. If eye convergence is used only to create 3D image perception, retinal focal cues and super-multiocular conditions can be used so that there are two or more view images entering the pupil of a single eye. In that regard, multi-view images may not be projected toward two eyes, for example, because two different views are sufficient to create an autostereoscopic effect. However, more than two views per eye can be used to create a larger eyebox around each eye, allowing for greater tolerance for eye movement.

[0169] The use of a cross-shaped patterned source and microlenses instead of a lenticular sheet allows for rotation of the multi-view image orientation. Such a feature can be used by mobile devices when changing display mode from portrait to landscape. Such a feature can also be used to reduce image processing (which can include image rendering). Compared to a full-parallax display (which can have a full matrix of emitters for each projector cell), for some embodiments, fewer light sources can be used for each projector cell. Because the number of emitter components is smaller, there can be fewer electrical contacts to the small light-emitting chips, and less control electronics can be used. Furthermore, a cross-shaped source pattern can allow more space for electrical wiring and controller components on the source module subassembly.

[0170] Because the light-collimating optics within the display structure produce well-collimated beams from each individual source component, the view beam can have a narrow FOV in both directions. Without any diffusing components, this can mean that if a user's pair of eyes is not positioned precisely in an aligned vertical location relative to the display, no image can be seen at all. For some embodiments, the view beam FOV can be increased by selectively diffusing the beam in one direction, which can be orthogonal to the direction in which the views are generated. The FOV increase can allow tolerance in vertical eye positioning, allowing the device to compensate for a user's hand-holding of the display device as well as the user's natural eye and head movements without losing the image. For many material-scattering-based diffusers, it is not possible to increase the FOV in only one direction. As a result, such diffusers cannot provide tolerance for vertical eye position by increasing the FOV only in the vertical direction. However, in contrast, for some embodiments, SELC diffusers provide one-directional diffusion and can switch between a transparent mode and a scattering mode.

[0171] For some embodiments, an LF display device, such as a smartphone, can include a sensor configured to detect display orientation, and the device can be configured to switch between selectively operating a first controllable diffuser to diffuse in a first direction and selectively operating a second controllable diffuser to diffuse in a second direction in response to a detected change in display orientation. Some embodiments can include a direction-controllable diffuser configured to diffuse in a vertical direction when the device is in portrait orientation, such that only a single vertical view is generated. For some embodiments, in response to a rotation of the device, the direction-controllable diffuser can enable diffusion in a rotated direction when the display orientation is changed from portrait to landscape, such that only a single view is generated in the direction of diffusion.

[0172] The diffuser functionality shown in Figures 14A and 14B can be used with a 3D multi-view display structure. For some embodiments, two separate stacked SELC diffuser components with orthogonal orientations can be used for two or three display modes. For some embodiments, the orientation of the LF display device can be detected, and horizontal and vertical light diffusion parameters can be selected based on the detected orientation. For example, if the LF display device detects that the orientation has switched between portrait and landscape modes, the LF display device can select horizontal and vertical light diffusion parameters such that the light beam is diffused horizontally in the landscape mode and vertically in the portrait mode, or vice versa.

[0173] FIG. 18 illustrates an exemplary 3D display structure with a tunable LC diffraction grating, according to some embodiments. Due to the limited tuning range of the LC material, the light scattering effect of the inner surface structure of the SELC diffuser 1808 may be low. For some embodiments, if the beam divergence increase using a single SELC structure is not sufficient, several components can be stacked for an amplified effect that can be under angular control. In some embodiments, adding an LC diffraction grating 1810 to the diffuser stack 1808 can increase the diffusion in one direction. FIG. 18 schematically illustrates one example of such a multi-view 3D display structure with a single active emitter 1812, 1814. Ordered fine grating lines induced in the LC material layer split the divergent beam 1816 into several sub-beams 1818, which combine to generate a beam with a wider FOV. For some embodiments, the individual divergent beam sections can have designed intensity profiles to achieve a homogeneous combined beam angular distribution. One example of such a profile is a Gaussian profile, which allows multiple beams to be combined to have a "top hat" type overall intensity distribution.

[0174] For some embodiments, the apparatus may include an array of one or more sets of light-emitting devices 1812, 1814 as part of the light-emitting layer 1802, a polarizer layer 1804, a microlens array (MLA) 1806, one or more diffusers 1808, and one or more diffraction gratings 1810. For some embodiments, at least one of the diffusers is a surface-effect liquid crystal (SELC) diffuser. For some embodiments, at least one of the diffraction gratings includes a liquid crystal (LC) material, such as the exemplary LC diffraction grating 1810 shown in FIG. 18 .

[0175] For some embodiments, a multi-view 3D display uses spatial multiplexing to perform image rendering by showing a series of 2D images from different perspectives in different directions using view beams generated in a projector cell. A display device can also be used as a multi-view 3D display with multiple views or as a general 2D display. The 2D display mode can be activated by showing the same image in each direction simultaneously using the same hardware used for 3D images. For some embodiments, both diffuser directions can be activated to widen the FOV. For some embodiments, the diffuser structure is thin and close to the emitter, and the spatial resolution of the 2D display surface is maintained. The diffuser can be used to eliminate the "picket fence" effect by gradually reducing pixel spacing. This feature can be used when the display is used in a head-mounted VR / AR / MR device. The switching speed requirements for the SELC diffuser can be low for switching image modes on mobile devices.

[0176] For some embodiments, switching can be activated using a motion sensor in the mobile device, so that active synchronization between the diffuser and the light emitter is not performed. Such a motion sensor can be used to select the correct source row orientation from the horizontal and vertical light beams. Since only one of these rows is used at a given time, the source driving electronics can be less complex.

[0177] For some embodiments, neither the light emitter nor the MLA need to be precisely aligned with the SELC diffuser. Because the diffusing surface has a continuous microstructure, slight variations in the horizontal and vertical directions can be tolerated. However, if the microstructure is of a tiled type, alignment can be used. Because the SELC diffuser component scatters light, and this function does not require precise location, slight variations in the depth direction can be tolerated. Very loose tolerances provide cost savings in the manufacturing process and allow the display to be robust to environmental factors such as temperature changes. This latter feature can be used with mobile devices used in changing environments.

[0178] Optical materials refract light with different wavelengths at different angles (chromatic dispersion). This means that when three colored pixels (e.g., red, green, and blue) are used, the different colored beams are tilted and focused in somewhat different directions and distances due to the refractive features. Because the colored subpixels can be spatially separated, small angular differences in the colored beam projection angles may exist. These angular differences can be compensated for in the optical structure, for example, by using hybrid layers where diffractive features are used for color correction. When different colored light emitters in a display are arranged with a corresponding layout, the SELC diffuser may be able to diffuse the different color emissions together in the viewing window, thereby reducing (or, for some embodiments, eliminating) optical- or rendering-based methods for color synthesis.

[0179] The SELC diffuser, when used with continuous control instead of switching between two modes, can be used for fine tuning of the 3D image. It can be used, for example, to blend different views together more smoothly in cases where the viewer is closer to the display or farther away and the view beam angle distribution needs to be adjusted for a more uniform distribution. For some embodiments, a mosaic diffuser with a local adjustment option can be used to diffuse neighboring view beams together, such as when pixel-level redundancy, a common feature of multi-view and LF imagery, exists in the 3D image content. The observer's eye position can also be actively detected in the device using a tracking module, and the image is projected only in the direction the eye is positioned and in the expanded FOV using the SELC diffuser. This can save some energy because the light is better concentrated, extending the battery life of mobile devices.

[0180] Several display manufacturers have developed products for switching between 2D and 3D display modes in devices that utilize basic lenticular sheet-based or microlens-based multi-view devices. Some of these systems use switchable LC diffusers, such as the exemplary systems described in U.S. Patent Nos. 5,629,999 and 5,749,343. The SELC diffuser provides angle adjustment that can be used to switch between 2D and 3D display modes. U.S. Patent No. 5,629,999 is understood to describe tilted lenticular sheets. For example, the one-way switchable diffusion properties of the SELC diffuser can be combined with a tilted lenticular sheet to achieve better 2D image mode resolution. Surface-based diffusing components, which have better light transmission than material-based scattering components, can be used to increase optical efficiency and reduce energy consumption.

[0181] One possible 3D display method utilizing SELC diffusing components is a projector-based device that utilizes angular selectivity. For volumetric displays, such as those described in U.S. Patent No. 5,629,997 and U.S. Patent No. 5,629,997, a series of LC diffusers are used as a switchable screen in conjunction with an image projector. SELC diffusers can be used for separate control of orthogonal diffusion directions, so that one switchable diffuser panel can scatter one image, while another panel diffuses another image with a crossed polarization and diffusion direction. Using such a device, the refresh rate of the overall volumetric 3D image can be increased because two sub-images can be shown simultaneously, instead of sequentially. Surface-based diffuser components can be designed to have better light transmission than material-based scattering components, increasing optical efficiency and reducing energy consumption.

[0182] For some embodiments, the device may include two or more diffusers (such as SELC diffusers), where a first diffuser is configured to scatter light displaying a first image using a first diffusion direction and a second diffuser is configured to scatter light displaying a second image using a second diffusion direction, where the first diffusion direction is orthogonal to the second diffusion direction.

[0183] When SELC diffusers are combined with mosaic lenses, several new functionalities and / or performance advantages can be achieved. Because the diffuser function is based on surface effects, different diffusion patterns can be combined using mosaic lenses. This combination allows for better control over the angular range of the projected beam section. For example, voxels positioned on the display surface can be generated without using fixed optical structures, enabling higher spatial resolution both on the display surface and in the virtual focal plane.

[0184] Patterned SELC diffusers can be used in augmented / mixed reality (AR / MR) headsets to improve image contrast. A diffuser surface with locally varying, tunable light-scattering properties can selectively diffuse sections of a real-world image onto which artificial image content is projected. This can improve overall image quality by diffusing bright features of the natural world, such as specular reflections and glare, which can significantly reduce image contrast. For some embodiments, at least one SELC diffuser can be configured to diffuse light to reduce glare for images projected by an array of one or more sets of light-emitting devices.

[0185] FIG. 19 is a schematic perspective view illustrating an exemplary mobile device viewing configuration, according to some embodiments. For some embodiments, the exemplary multi-view 3D display can use a SELC diffuser component. FIG. 19 shows a mobile device with a 6-inch multi-view 3D display 1904 positioned at a viewing distance 1906 of 500 mm from a viewer 1902. The display is capable of projecting 13 different views separately in both horizontal and vertical directions. The mobile device can be rotated 90°, for example, to change the image mode from portrait to landscape (see FIG. 17). In both modes, a single set of 13 views is generated for each multi-view 3D image in the direction of the eye pair to create a stereoscopic effect. The use of 13 views can allow for rotation of the device to obtain a better 3D experience from a different viewpoint in one direction. Two orthogonally stacked SELC diffusers with LC diffraction gratings are used to selectively expand the FOV of the narrow view beam in two orthogonal directions into a relatively wide viewing window that allows for handheld use of the device and adjustment to natural head and eye movements.

[0186] FIG. 20 illustrates an exemplary μLED pattern layout, according to some embodiments. FIG. 20 illustrates the layout and dimensions (in μm) of a μLED array used as a source in an exemplary display layout. For some embodiments, the exemplary array has 23 red (“R”) light source components 2006, 23 green (“G”) light source components 2008, and 23 blue (“B”) light source components 2010 arranged in a cross-shaped (or plus-shaped) pattern. The size 2018 of the individual components is 2 μm × 2 μm, and the pitch 2020 is 3 μm. The total footprint of the source pattern is 38 μm × 38 μm (2012, 2014). The μLEDs are bonded to a 42 μm × 42 μm substrate (or a 50 μm × 50 μm (2016) substrate for some embodiments), which includes electrical contacts for the individual sources for the source module. The tiny light-emitting components can be joined into subassemblies that can be made with higher precision manufacturing methods than those used in assembling the entire display. The layout of the three different color components allows for the projection of 13 full-color image beams (each of which can correspond to a full-color horizontal pixel 2002 or a vertical pixel 2004) separately in both the vertical and horizontal directions with high angular resolution, depending on the display image mode.

[0187] FIG. 21 illustrates an exemplary display optics structure, according to some embodiments. FIG. 21 schematically illustrates the structure and dimensions (in μm) of an exemplary optical display. For some embodiments, a 22 μm thick linear polarizer sheet 2110 can be laminated to an approximately 28 μm thick polycarbonate microlens sheet 2112 fabricated using hot embossing. The microlenses can have rectangular 50 μm × 50 μm apertures, and the rotationally symmetric aspheric lens shape can have a 35 μm radius and a −0.8 conic constant. The 50 μm thick 2124 polarizer-microlens sheet 2124 can be positioned 25 μm (2122) from the μLED array 2106, which is attached to a common backboard 2102, which can include one or more subassemblies (or source modules) 2104. Such subassemblies can have a layout as shown in, for example, FIG. 16A , FIG. 16B , or FIG. 20 , or another layout. The backboard 2102 can include electrical contacts for the source modules 2104. An opaque, hot-embossed plastic baffle aperture sheet 2108 can be used as a precision spacer between the lenses and sources and for stray light suppression between display projector cells formed by a single source module and microlenses. The source modules can be, for example, 38 μm (2118) wide, as shown. Together, the sources and microlenses form a multi-view display structure capable of projecting 13 full-color beams from each projector cell to a total FOV (field of view) 2130 of 38° in both vertical and horizontal directions. For some embodiments, a 6-inch (15.24 cm) diagonal display can include a 1500 x 2660 array of 50 μm pitch size 2120 projector cells, corresponding to a 2.95 inch x 5.24 inch (7.49 cm x 13.31 cm) display and 508 pixels per inch (PPI). Some current high quality 2D displays on mobile phones have a resolution of around 500 PPI.

[0188] For some embodiments, a one-dimensional array of 13 full-color pixels can generate 13 different views within a total FOV of 38°. A single view beam can have a FOV of approximately 3.4° full width at half maximum (FWHM), meaning that the beam has a width of approximately 30 mm at a viewing distance of 500 mm. For a single projected view beam visible to only one eye in one direction at any given time, such a display structure can be used to generate a stereoscopic 3D image. Because views projected from the edge of the display overlap with views projected from the center of the display, there is a small, varying offset within each projector cell between the source module and the microlens location across the display surface. At the center of the display, the offset is 0, and the source module can be centered on the microlens. At the extreme edge in the wider direction, the offset is 7.5 μm. At other locations between the center and the edge, the offset can be selected linearly between these two values. The total width of the viewing window is approximately 350 mm between the extreme viewing beam projection directions shown in FIG.

[0189] For some embodiments, two orthogonal orientation sets 2114, 2116 of stacked-together SELC diffusers and LC gratings can be positioned between the microlens (MLA) 2112 and the user. As shown in FIG. 21 , two orthogonal orientation sets of stacked-together SELC diffusers and LC gratings can be used to selectively diffuse a projection beam in two orthogonal directions. For some embodiments, the entire optical display structure can have a thickness of less than 1 mm, even with a 0.5 mm thick protective glass top layer, which can be considered “thin enough” for, for example, a mobile phone device. Because the diffuser component has a continuous microstructure, slight variations in any of the three dimensions between the multi-view display structure and the diffusing layer can be tolerated. For some embodiments, only rotational positioning between different display structures is determined. For some embodiments, rotational positioning between different display structures has greater tolerance because the positioning only affects the diffusion direction. The diffuser is used to expand the FOV of the image beam in one direction, so that when the light beam is diffused, the colors emitted from neighboring μLEDs can blend together. As a result, for some embodiments, no special color combining method is used. The diffusion property can be used to even out variations between source component intensities and between the exact location of the light source relative to the microlens. As a result, a uniform overall image can be produced.

[0190] For some embodiments, the SELC diffuser component can be constructed from two thin Zeonex E48R polymer substrates and a layer of liquid crystal material, which can have a refractive index matching that of the substrates (approximately 1.53 at a wavelength of 589 nm). The refractive index tuning range of the LC material can be approximately 0.02 in one light polarization direction. Both polymer sheets can have transparent ITO electrode coatings, and the LC material can be disposed between the two layers. The polymer sheets can have two different one-dimensional surface microstructures that follow a surface shape gradient distribution common to the two different optical shapes. Both polymer sheets can have an aperture width of 5 μm with different surface shape parameters. For some embodiments, the first respective optical shape can have a radius of 2.75 μm, and the second optical shape can have a radius of 0.75 μm and a conic constant of -1. These surface structures diffuse a light beam in one direction when a voltage is applied to the electrodes, creating a refractive index difference between the LC material and the surrounding foil. When the voltage is turned off, the refractive index difference disappears and the material interface becomes transparent to the incoming beam. A switchable LC diffraction grating, having the same structure as that described in

[13] , is laminated to the SELC diffuser, together forming a single, approximately 76 μm thick, tunable directional diffuser component 2126, 2128. For some embodiments, the display structure can have two diffuser components stacked side by side, oriented in orthogonal directions, for selective diffusion of the beam in the vertical and horizontal directions.

[0191] With a refractive index difference of 0.02 between the two optical interfaces between the LC material and both polymer substrates, the surface microstructure gradient distribution of the SELC diffuser can change a well-collimated beam into a diffuse beam with a near-Gaussian intensity profile and a FWHM (full-width at half-maximum) divergence of approximately 8°. The diffuser component diffraction grating can diffract the incoming beam's optical energy evenly (approximately 33% each) into three orders (-1, 0, +1), with the first-order (-1, +1) beam tilted approximately 6° on either side of the zeroth-order (0) beam. These three near-Gaussian beam sections merge to form a single diffused viewing beam that is wider than the individual diffused beam sections in the diffraction direction. The combination of the SELC diffuser and the LC diffraction grating can change the divergence of a well-collimated beam into a diffuse beam with a FWHM divergence of approximately 18°. Using this divergence value, a single full-color beam generated using one full-color pixel inside one display projector cell may be able to cover a viewing window approximately 160 mm high at the display viewing distance. A total viewing window size of 160 mm x 350 mm may be "adequate" for, for example, a handheld mobile device, because this window size may be able to compensate for some shaking of the hand, as well as small eye and head movements.

[0192] For some embodiments, the apparatus can include a backboard and one or more baffles, where an array of one or more sets of light-emitting devices is mounted on the backboard, each set of light-emitting devices corresponding to a respective baffle, and each baffle at least partially separating each set of light-emitting devices from the remainder of the array of one or more sets of light-emitting devices. Figure 21 shows an example of such an apparatus.

[0193] For some embodiments, the apparatus can be configured such that at least one of the diffusers is configured to diffuse light emitted by at least one of the light-emitting devices in a horizontal direction and at least one of the diffusers is configured to diffuse light emitted by at least one of the light-emitting devices in a vertical direction. Figure 21 shows an example of such an apparatus.

[0194] FIG. 21 schematically illustrates the structure of an exemplary 3D multi-view display that can be used, for example, in a mobile phone device. Light is emitted from an array of μLEDs 2106 and linearly polarized using a polarizing component 2110 attached to a microlens array (MLA) 2112. The MLA 2112 collimates the emitted and polarized light into a beam that strikes a stack of liquid crystal (LC)-based components 2114, 2116. Two of the components are SELC diffusers and two are LC gratings. One SELC diffuser is used to diffuse light only in the vertical direction, and the other only in the horizontal direction. The same applies to the LC grating. LC gratings can enhance light diffusion in either direction if a broader scattering distribution is used, but in some embodiments, the SELC diffuser can be operated without an LC grating. Emitted image beams 2132, 2134, 2136, 2138 show single pixel view directions for edge rays emitted from two different light sources. Exemplary emitted image beams 2132, 2134, 2136, 2138 are shown without any diffusion.

[0195] The display device in FIG. 21 can be operated in three modes. In the first mode, the first SELC diffuser is "off" and the second SELC diffuser is "on." The LC layer inside the second SELC twists the direction of polarization so that the interface between the birefringent LC material and the linearly structured substrate layer causes diffusion. Light is diffused only in the vertical direction for a mobile device display viewed in portrait mode. In the horizontal direction, incident linearly polarized light strikes the interface between the LC material inside the first SELC diffuser and the substrate, and the light is not diffused because the LC material and the substrate have matching refractive indices in the horizontal direction. For this reason, the display can generate different images for different horizontal directions. As a result, a 3D stereoscopic image is generated for the viewer. This use case is depicted on the left side of FIG. 17, where, for example, 13 views are generated in portrait mode 1702.

[0196] In the second mode, the first SELC diffuser is "on" and the second SELC diffuser is "off." Light is diffused only in the horizontal direction for a mobile device display viewed in portrait mode. In the vertical direction, light is not diffused because the second SELC internal interface between the birefringent LC material and the linearly structured substrate layer is now optically transparent. The display can generate different images for different vertical directions. In this case, when the phone is used in portrait mode, the viewer does not see a 3D image. However, when the phone is rotated 90 degrees to landscape mode, a different image becomes visible to the viewer, and a 3D image is seen. This use case is depicted on the right side of FIG. 17, where, for example, 13 views are generated in landscape mode 1704.

[0197] In a third mode, both SELC diffusers are "on." The LC layers twist the polarization of light incident on both diffusers so that their internal interfaces have a refractive index difference, scattering the light both vertically and horizontally. In this case, the display cannot produce different images in either the vertical or horizontal direction, but the mode can be used with 2D images instead of stereoscopic 3D images. For some embodiments, a combination of SELC diffusers, LC gratings, and μLED activation can be used to limit the angular range of light emitted in 2D mode. This feature can be used, for example, in a privacy mode, where only a single viewer sees the image.

[0198] Some embodiments of LF display structures include a display (which may include one or more light-emitting elements), a first controllable diffuser overlying the display, the first controllable diffuser selectively operable to diffuse light in a first direction, and a second controllable diffuser overlying the display, the second controllable diffuser selectively operable to diffuse light in a second direction substantially perpendicular to the first direction. For some embodiments, at least one of the first controllable diffuser and the second controllable diffuser may comprise a surface-effect liquid crystal (SELC) diffuser. For some embodiments, at least one LC diffraction grating and at least one of the first controllable diffuser and the second controllable diffuser may comprise a birefringent material. For some embodiments, the diffraction grating may comprise a birefringent material.

[0199] To test the optical functionality of the structure, a set of simulations was performed using the optical simulation software OpticsStudio 17. The described optical display structure was positioned 500 mm from the detector plane, and four different cases were simulated. In the first three cases, three sources were used, positioned at the center and two horizontal edges of a cross-shaped source pattern. These tests were conducted to model the optical properties of the multi-view optical system and to investigate the selective diffusion properties of the adjustable diffuser component. In the final simulation case, a horizontal row of 13 sources was used. In this case, both the vertical and horizontal diffusers were activated to demonstrate the width and height of the viewing window that can be generated using a single projector cell in a selected direction. All of the simulated sources had a green center wavelength of 550 nm and a spectral width of 20 nm, and the sources were positioned within the single projector cell structure. Simulation results are presented in Figures 22A-22D, showing the irradiance distribution as a 2D map of a 500mm x 500mm detector area at a viewing distance of 500mm. The same information is shown as an irradiance profile in Figures 23-25.

[0200] 22A is a diagram showing an example simulated irradiance distribution without a diffuser, according to some embodiments. The first distribution image 2200 in FIG. 22A shows that when the diffuser is not activated, the three active sources appear as three separate spots inside the viewing window.

[0201] Figure 22B shows an example simulated irradiance distribution with a SELC diffuser, according to some embodiments. The second 2D distribution image 2220 in Figure 22B shows how the beam is diffused in the vertical direction when the vertical SELC diffuser is activated.

[0202] Figure 22C shows an example simulated irradiance distribution using a SELC diffuser and diffraction grating, according to some embodiments. The third 2D distribution image 2240 presented in Figure 22C shows how an activated vertical LC grating further increases diffusion in the vertical direction. In Figures 22B and 22C, the horizontal distribution remains the same, demonstrating the angle-selective diffusion properties of the system.

[0203] 22D shows an example simulated irradiance distribution when the horizontal and vertical diffusers are activated, according to some embodiments. The fourth 2D distribution image 2260 in FIG. 22D shows that the angular beams are diffused together in both the horizontal and vertical directions.

[0204] Figure 23 is a graph showing an example horizontal irradiance distribution for a deactivated horizontal diffuser and diffraction grating, according to some embodiments. The irradiance distribution of three sources at the viewing window with a horizontal diffuser and diffraction grating is shown as a graph of normalized irradiance 2302 versus horizontal position 2304. In Figure 23, the spots have a diameter of about 25 to 30 mm full width at half maximum (FWHM), and the spots have a distribution profile that is close to Gaussian. Figure 23 corresponds to the optical display structure shown in Figure 22A.

[0205] FIG. 24 is a graph showing exemplary vertical irradiance distributions for three configurations, according to some embodiments. The irradiance distributions of a single central source in the viewing window using the three configurations are shown as a graph of normalized irradiance 2402 versus vertical position 2404. The first trace 2406 corresponds to the configuration without a diffuser or diffraction grating. The second trace 2408 corresponds to the configuration with a diffuser but without a diffraction grating. The third trace 2410 corresponds to the configuration with a diffuser and a diffraction grating. FIG. 24 presents a comparison of three simulated irradiance profiles in the vertical direction when the vertical diffuser and diffraction grating are activated separately. FIG. 24 corresponds to the optical display configurations shown in FIGS. 22B, 22C, and 22D. These profiles were taken from the vertical centerlines of the distributions in FIGS. 22A, 22B, and 22C. The graph shows that when the SELC diffuser is activated, the view beam width increases from about 25 mm FWHM to about 70 mm in the viewing window. This means that the tolerance for vertical eye pupil positioning has increased by about three times. When the diffraction grating is activated along with the SELC, the width increases to about 160 mm, which is more than six times larger than the original beam width and allows for a much larger relative vertical position shift between the display and the viewer's eye. This comparison shows that a significant increase in view beam FOV can be achieved with the presented optical structure, thereby improving usability.

[0206] The profile in Figure 24 shows an irradiance distribution normalized to a peak value of 1. However, if the beam is diffused and the same light energy is spread over a larger surface area in the viewing window, the peak irradiance value will also decrease in relation to the increased beam width, and the user may see a dimmer image. For some embodiments, a higher current can be used to drive the μLEDs to compensate and increase the total light output.

[0207] This feature can also be used, for example, in the case of a mobile phone with a front-facing camera that can identify the viewer's eye position. When the viewer's eye is correctly positioned at the projection centerline of the display, the SELC diffuser and / or LC grating may not be activated, and the μLEDs can be driven using a lower current. This mode can save energy and extend the usage time of battery-operated devices. For some embodiments, the use of two different beam width-changing layers can enable the use of (for example) three viewer eye-position zones to adjust display power consumption accordingly.

[0208] FIG. 25 is a graph showing an example irradiance distribution for the horizontal orientation of a light source when using horizontal and vertical diffusers and a diffraction grating, according to some embodiments. The irradiance distribution of one horizontal source row in a viewing window when using horizontal and vertical diffusers and a diffraction grating is shown as a graph of normalized irradiance 2502 versus horizontal position 2504. FIG. 25 shows simulated irradiance profiles taken from the 2D distribution shown in FIG. 22D. These profiles show the width and height of the viewing window that can be achieved by activating a horizontal row of 13 sources along with the horizontal and vertical diffusers. This window, approximately 160 mm by 350 mm in size, can be covered by all projector cells in the display matrix. When both the horizontal and vertical diffusers are activated simultaneously, angular resolution of the view beam is lost because the beams are diffused together. This feature can be used to display images using a display in 2D mode. Since the viewing window still has a limited size, the 2D image is only visible to a single user, and the optical structure acts as an effective privacy filter. Due to the fact that the μLEDs are arranged in a cross-shaped pattern, the orientation of this viewing window can be freely rotated by 90° when the display device is rotated, for example, from landscape to portrait mode.

[0209] For some embodiments, independent horizontal and vertical light diffusion parameters can be selected such that one or more diffusers perform simultaneous horizontal and vertical diffusion. For some embodiments, a first set of one or more diffusers can be configured to perform horizontal diffusion, and a second set of one or more diffusers can be configured to perform vertical diffusion. The first and second sets of diffusers can be stacked in parallel, for example, such that a light beam is diffused for simultaneous horizontal and vertical diffusion.

[0210] For some embodiments, a smaller number of source components can be used to manufacture a display. For some embodiments, a cross-shaped μLED pattern can include a total of 69 active source components, which is approximately 59% fewer than a source module using a full array (13 × 13 = 169 components). The use of a cross-shaped μLED pattern can enable the use of a less complex electrical layout because there are fewer μLEDs than a full array, and less substrate surface is occupied by the μLEDs. This can result in reduced costs.

[0211] A cross-shaped arrangement can mean that fewer images are generated for each 3D multi-view image when views are generated in only one direction. As a result, image processing requirements (such as rendering and display timing) can be lower. Having only one directional multi-view parallax image at any one time may be deemed sufficient by users for many use cases and can enable the use of lower-cost 3D systems on more devices.

[0212] For some embodiments, the optical image display structure can include an adjustable light diffusing component. Some embodiments of the method can include diffusing light using the adjustable light diffusing component. For some embodiments, the optical image display structure can include a 3D multi-view display device. Some embodiments of the method can include displaying a multi-view 3D image using the 3D multi-view display device. For some embodiments, the SELC diffuser can be used to control an illumination pattern generated using, for example, an LED lamp. The SELC diffuser can be electronically adjusted to diffuse light evenly over a wide area or to project a spotlight. The SELC diffuser can be used, for example, in security / privacy glass windows that can be switched between a transparent mode (allowing light to pass through the glass window) and a translucent mode (blocking light from passing through the glass window). Because SELC diffusers have surface effects, some SELC diffusers can be designed to have different angular scattering and spectral selectivity characteristics compared to material scattering-based diffusers, many of which scatter light evenly over a range of angles. For some embodiments, the SELC diffuser can be used as an adjustable diffuser with many types of 3D displays.

[0213] Many of the optical components of SELC diffusers can be produced using large-scale manufacturing methods, such as nanoimprinting, making them low-cost in mass production. Some diffusers with surface microstructures and engineered gradient distributions are available in large sheet format. Similar structures and manufacturing methods can be used to produce tunable diffuser structures. Wafer-level manufacturing using UV-curable optical materials and glass wafers can sometimes be used due to the precision requirements of small screen sizes.

[0214] LC-based components typically use linearly polarized light, which can reduce optical efficiency and increase power consumption. Because LCDs are typically polarization-dependent devices, light propagation control components can be used in 3D displays without the high cost of efficiency. For example, recent developments in using cholesteric LCs (instead of the more common nematic phase crystals), which can be used for beam spreading without polarization dependence (Non-Patent Document 3), allow for increased component transmittance for OLED- or μLED-based display panels.

[0215] For some embodiments, high-quality goggle-less 3D displays use small-scale light sources, such as μLEDs, to achieve very small view beam sizes and high levels of collimation. For some embodiments, the active optoelectronic layers (e.g., light emitters, SELC diffusers, and / or LC gratings) can be controlled to operate synchronously.

[0216] For some embodiments, the SELC diffuser can be segmented so that different portions have different degrees of diffusion. Such segmentation can be used to generate spatially adaptive directional densities. In such devices, some spatial regions of the image can be reproduced using different views with fine angular differences, while other spatial regions can be reproduced using a coarse angular density of views.

[0217] Conventional display devices operating with such content can have a uniform angular view density that is equal in all spatial areas. As a result, redundant views may be generated and displayed in areas with a coarse angular density. With a SELC diffuser, a spatial area with a coarse angular density can be generated using a single view and a high level of diffusion, so that light in all viewing directions is generated through diffusion rather than displaying redundant narrow views. As a result, the displayed image can be more uniform than an image composed of several individual narrow beams. With a SELC diffuser, if the content exhibits large view-to-view variations such that the uniformity tolerance is overwhelmed by content variations, individual narrow beams can be used for some embodiments. Thus, the use of a spatially patterned SELC diffuser can improve display quality and reduce the bandwidth required to display redundant views.

[0218] FIG. 26 is a message sequence diagram illustrating an exemplary process for processing and displaying 3D images, according to some embodiments. For some embodiments, display control 2604 can perform a process that includes receiving a field of view (FOV) selection from user input 2602 at 2608. For some embodiments, display control 2604 can be used, for example, to activate a privacy setting, such that the image is visible in a limited FOV, or a power-saving mode, such that light is directed from the pixels only toward the user's eyes. The user can also switch the display between 2D and 3D display modes. In 2D display mode, for some embodiments, it is not necessary to have directional control over the pixel images, so that, for example, only a few of the light-emitting components behind each pixel are used, with an activated diffuser.

[0219] The process may further include, at 2610, the display control 2604 selecting diffusion parameters based on the FOV selection. The process may further include the display control 2604 selecting independent horizontal and vertical light diffusion parameters based on the FOV selection. For example, if a wide-angle FOV is selected by the user, the display control 2604 may select a larger lens aperture height. For example, if the user selects a narrower-angle FOV, the display control may select a smaller lens aperture height. The process may further include, at 2612, the display control 2604 receiving an orientation from the user. The process may further include, at 2614, the display control 2604 sending diffusion control information (such as the horizontal and vertical light diffusion parameters) to the display hardware 2606. The process may further include, at 2618, the display control 2604 receiving a 3D mode setting (such as a selection indicating either 2D mode or 3D mode) from the user input 2602. The process may further include the display control 2604 selecting a brightness setting, at 2616. The process may further include the display control 2604 rendering an image, at 2620. The process may further include the display control 2604 sending brightness information, such as backlight information, to the display hardware 2606, at 2622. The process may further include the display control 2604 sending the rendered image to the display hardware 2606, which may be optical hardware of an LF display device, at 2624.

[0220] For some embodiments, the process may include emitting a light beam from a light-emitting device and adjusting the brightness of the emitted light beam based on the FOV selection. For example, the brightness may be adjusted to maintain a similar brightness level for an image viewed by a user. If a wider FOV is selected, the brightness may be increased, while if a narrower FOV is selected, the brightness may be decreased. Such brightness changes may occur because wider FOVs have greater light diffusion than narrower FOVs. For some embodiments, adjusting the brightness may include adjusting current and / or voltage levels to one or more light-emitting devices, such as micro-light-emitting diodes (μLEDs).

[0221] For some embodiments, selecting the independent horizontal and vertical light diffusion parameters can be based on 2D / 3D mode selection. For example, when 2D mode is selected, the diffuser can be set to pass light without diffusion (or with very little diffusion) in both the horizontal and vertical dimensions, as shown in FIG. 12A. In 3D mode, for example, the diffuser can be enabled to diffuse light in the horizontal and / or vertical dimensions to enable a 3D image to be displayed.

[0222] For some embodiments, the device may include a processor and may be configured to perform the processes. For some embodiments, the display control may include a processor that performs the display control portion of the process. For some embodiments, the display hardware may include a processor that performs the display hardware portion of the process. For some embodiments, one or more processors may be used to perform one or more portions of the process.

[0223] FIG. 27 is a flowchart illustrating an example process for processing and rendering a 3D image, according to some embodiments. For some embodiments, process 2700 may be performed, including receiving a field of view (FOV) selection for a light field (LF) display device at 2702. For some embodiments, process 2700 may further include selecting independent horizontal and vertical light diffusion parameters based on the FOV selection at 2704. For some embodiments, process 2700 may further include rendering one or more images for the LF display device at 2706. For some embodiments, process 2700 may further include emitting a light beam from each of the one or more light-emitting devices to display the one or more rendered images using the LF display device at 2708. For some embodiments, an apparatus may include a processor and may be configured to perform the process. For some embodiments, the apparatus may include a processor and may be configured to control one or more light-emitting devices to emit light. For some embodiments, the apparatus may be configured to control a light diffuser, such as an SELC diffuser.

[0224] FIG. 28 is a flowchart illustrating an exemplary process for processing and rendering a 3D image, according to some embodiments. For some embodiments, the exemplary process may include emitting a light beam from one or more light-emitting devices. For some embodiments, the exemplary process may further include polarizing the light beam into a linearly polarized beam. For some embodiments, the exemplary process may further include passing the light beam through a liquid crystal (LC) material. For some embodiments, the exemplary process may further include passing the light beam through a birefringent material. For some embodiments, the exemplary process may further include applying a voltage to the LC material to change the light polarization configuration state of the LC material. For some embodiments of the exemplary process, changing the light polarization configuration state may switch from a first polarization state to a second polarization state. For some embodiments of the exemplary process, the first polarization state may diffuse the light beam in a first direction upon passing through the birefringent material, and the second polarization state may diffuse the light beam in a second direction upon passing through the birefringent material.

[0225] Although methods and systems according to some embodiments are discussed in the context of virtual reality (VR), some embodiments may be applied in the context of mixed reality (MR) / augmented reality (AR) as well. Also, while the term "head-mounted display (HMD)" is used herein according to some embodiments, some embodiments may be applied to, for example, a wearable device (which may or may not be head-mounted) capable of VR, AR, and / or MR.

[0226] An exemplary method according to some embodiments may include determining horizontal and vertical light diffusion parameters based on a field of view (FOV) selection, sending the horizontal and vertical light diffusion parameters to optical hardware of a light field (LF) display device, rendering one or more images for the LF display device, and sending the one or more rendered images to the LF display device.

[0227] For some embodiments of the example method, determining the horizontal and vertical light diffusion parameters may include selecting a horizontal and vertical light diffusion parameter.

[0228] For some embodiments of the exemplary method, the horizontal light diffusion parameter can be independent of the vertical light diffusion parameter.

[0229] In some embodiments, an exemplary method may include receiving an FOV selection for an LF display device.

[0230] For some embodiments of the exemplary method, the horizontal may be orthogonal to the vertical, and the horizontal and vertical may be relative to the LF display in the xy plane.

[0231] In some embodiments, an exemplary method may include emitting a light beam from a light-emitting device of an LF display device, and modifying a horizontal angle of diffusion of the emitted light beam based on one or more horizontal light diffusion parameters.

[0232] For some embodiments of the example method, modifying the horizontal angle of diffusion of the emitted light beam based on the one or more horizontal parameters may include determining whether one of the horizontal parameters is within a threshold range, and activating a diffuser to increase the horizontal angle of diffusion of the emitted light beam if one of the horizontal parameters is within the threshold range.

[0233] In some embodiments, an exemplary method may include emitting a light beam from a light-emitting device of an LF display device and modifying the vertical diffusion spread of the emitted light beam based on one or more vertical light diffusion parameters.

[0234] In some embodiments, an exemplary method may include emitting a light beam from a light-emitting device of an LF display device and adjusting the brightness of the emitted light beam based on the FOV selection.

[0235] For some embodiments of the exemplary method, the step of selecting independent horizontal and vertical light diffusion parameters may select horizontal and vertical light diffusion parameters that activate respective horizontal and vertical diffusers for simultaneous horizontal and vertical diffusion.

[0236] In some embodiments, the exemplary method may include detecting an orientation of the LF display device and detecting an orientation of a user, and selecting the horizontal light diffusion parameter and the vertical light diffusion parameter may be further based on at least one of the orientation of the LF display device and the orientation of the user.

[0237] In some embodiments, the exemplary method may include receiving a 2D / 3D mode selection, and selecting independent horizontal and vertical light diffusion parameters is further based on the 2D / 3D mode selection.

[0238] For some embodiments of the exemplary method, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may indicate whether to apply a voltage to a portion of one or more diffusers.

[0239] For some embodiments of the example method, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may indicate an amount of voltage to apply to a portion of one or more diffusers.

[0240] For some embodiments of the example method, one of the horizontal light diffusion parameters may indicate a target amount of diffusion to be introduced in the horizontal direction.

[0241] For some embodiments of the exemplary method, one of the vertical light diffusion parameters may indicate a target amount of diffusion to be introduced in the vertical direction.

[0242] An exemplary apparatus according to some embodiments may include a processor and a non-transitory computer-readable medium storing instructions that, when executed by the processor, are operable to perform any of the exemplary method embodiments.

[0243] An additional exemplary method according to some embodiments may include determining horizontal and vertical light diffusion parameters based on a field of view (FOV) selection, rendering one or more images for a light field (LF) display device, and emitting a light beam from each of one or more light-emitting devices of the LF display device to display the one or more rendered images by the LF display device using the horizontal and vertical light diffusion parameters.

[0244] For some embodiments of the additional exemplary method, determining the horizontal and vertical light diffusion parameters may include selecting a horizontal and vertical light diffusion parameter.

[0245] For some embodiments of the additional exemplary method, the horizontal light diffusion parameter can be independent of the vertical light diffusion parameter.

[0246] In some embodiments, additional exemplary methods may further include receiving an FOV selection for the LF display device.

[0247] For some embodiments of additional exemplary methods, the horizontal may be orthogonal to the vertical, and the horizontal and vertical may be relative to the LF display in the xy plane.

[0248] In some embodiments, additional exemplary methods can include modifying a horizontal angle of diffusion of at least one of the emitted light beams based on a horizontal light diffusion parameter.

[0249] For some embodiments of the additional exemplary method, modifying the horizontal angle of diffusion of the emitted light beams can be based on one or more horizontal parameters and includes determining whether one of the horizontal parameters is within a threshold range, and activating a diffuser to increase the horizontal angle of diffusion of at least one of the emitted light beams if one of the horizontal parameters is within the threshold range.

[0250] In some embodiments, additional exemplary methods may further include modifying the vertical diffusion extent of at least one of the emitted light beams based on a vertical light diffusion parameter.

[0251] In some embodiments, additional exemplary methods may further include adjusting the brightness of at least one of the emitted light beams based on the FOV selection.

[0252] For some embodiments of additional exemplary methods, determining the horizontal and vertical light diffusion parameters may further include selecting independent horizontal and vertical light diffusion parameters, and the method may further include activating respective horizontal and vertical diffusers of the LF display device to simultaneously diffuse one or more of the emitted light beams using the independent horizontal and vertical light diffusion parameters for simultaneous horizontal and vertical diffusion.

[0253] In some embodiments, an additional exemplary method may include detecting an orientation of the LF display device, and selecting independent horizontal and vertical light diffusion parameters may be further based on the orientation of the LF display device.

[0254] In some embodiments, an additional exemplary method may include receiving a 2D / 3D mode selection, and selecting independent horizontal and vertical light diffusion parameters may be further based on the 2D / 3D mode selection.

[0255] For some embodiments of the additional exemplary method, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may indicate whether to apply a voltage to a portion of one or more diffusers.

[0256] For some embodiments of the additional exemplary method, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may indicate an amount of voltage to apply to a portion of one or more diffusers.

[0257] For some embodiments of the additional exemplary method, one of the horizontal light diffusion parameters may indicate a target amount of diffusion to be introduced in the horizontal direction.

[0258] For some embodiments of the additional exemplary method, one of the vertical light diffusion parameters may indicate a target amount of diffusion to be introduced in the vertical direction.

[0259] An additional exemplary apparatus according to some embodiments may include a processor and a non-transitory computer-readable medium storing instructions that, when executed by the processor, are operable to perform any of the additional exemplary method embodiments.

[0260] Further exemplary apparatus according to some embodiments may include an array of light-emitting devices, a polarizer layer, a microlens array (MLA), one or more diffusers, and one or more diffraction gratings.

[0261] For some embodiments of the further exemplary apparatus, the array of light-emitting devices may include one or more sets of light-emitting devices.

[0262] For some embodiments of the further exemplary apparatus, each of the one or more sets of light-emitting devices may include a pixel.

[0263] In some embodiments, further exemplary apparatus may further include a backboard and one or more baffles, wherein an array of one or more sets of light-emitting devices may be mounted to the backboard, wherein each set of light-emitting devices in the array may correspond to a respective baffle, and wherein each baffle may at least partially separate each set of light-emitting devices from the remainder of the array of one or more sets of light-emitting devices.

[0264] For some embodiments of the further exemplary apparatus, at least one of the one or more diffusers may be configured to diffuse light emitted by at least one of the light-emitting devices in a horizontal direction, and at least one of the one or more diffusers may be configured to diffuse light emitted by at least one of the light-emitting devices in a vertical direction.

[0265] For some embodiments of the further exemplary apparatus, at least one of the one or more diffusers may be configured to switch between diffusing light emitted by at least one of the light-emitting devices in a horizontal direction and diffusing light in a vertical direction.

[0266] In some embodiments of the further exemplary apparatus, at least one of the one or more diffusers can be a surface effect liquid crystal (SELC) diffuser.

[0267] For some embodiments of further exemplary devices, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, the LC material layer configured in cooperation with the first and second substrates to selectively provide at least one of angular orientation adjustment, or horizontal orientation adjustment and / or vertical orientation adjustment relative to the plane of the SELC diffuser, in response to an applied voltage.

[0268] In some embodiments of further exemplary devices, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, the LC material layer and the first and second substrates having selected material properties that work in conjunction and in concert to achieve steering of the light beam.

[0269] For some embodiments of the further exemplary apparatus, at least one of the diffusers can be configured to switch between a two-dimensional display mode and a three-dimensional display mode.

[0270] For some embodiments of the further exemplary device, a first one of the diffusers can be a SELC diffuser configured to scatter light displaying a first image using a first diffusion direction, and a second one of the diffusers can be a SELC diffuser configured to scatter light displaying a second image using a second diffusion direction, and the first diffusion direction can be orthogonal to the second diffusion direction.

[0271] For some embodiments of the further exemplary apparatus, at least one of the diffusers can be a SELC diffuser configured to diffuse light to reduce glare on the image projected by the array of light-emitting devices.

[0272] For some embodiments of the further exemplary device, at least one of the gratings can include a liquid crystal material.

[0273] For some embodiments of the further exemplary apparatus, at least one of the diffraction gratings can include a birefringent material.

[0274] For some embodiments of the further exemplary apparatus, at least one of the one or more diffusers may be configured as a mosaic diffuser to together diffuse one or more neighboring light beams emitted by one or more of the light-emitting devices.

[0275] An exemplary optical element according to some embodiments can include a first layer including electrically tunable liquid crystals capable of changing the polarization state of light passing through the first layer depending on the state of electrical tuning, and a second layer including birefringent material in a layer parallel to the first layer that includes surface structures designed to impart alternating diffusion properties to the beam, such that light incident on the second layer in a first polarization state can be scattered according to a first angular pattern and light incident on the second layer in a second polarization state can be scattered according to a second angular pattern.

[0276] An exemplary 3D display device according to some embodiments may include elements that provide direction-controllable diffusion, including a plurality of light-emitting elements and collimating microlenses that are capable of generating a collimated beam of light, and a direction-controllable diffuser that is switchable between a first state in which the light is diffused in a first direction and a second state in which the light is diffused in a second direction.

[0277] In some embodiments of the exemplary 3D display device, the diffusion may be in the vertical direction, and the multiple light-emitting elements are configured such that when no other views are rendered, when the corresponding light-emitting element is not powered, and when the display is in portrait orientation, only a single vertical view is produced.

[0278] In some embodiments of the exemplary 3D display device, the direction of diffusion can rotate in response to rotation of the display, and the multiple light-emitting elements are configured such that only a single view is generated in the direction of diffusion when no other views are rendered, when the corresponding light-emitting element is not powered, and when the display orientation changes from portrait to landscape.

[0279] For some embodiments of the exemplary 3D display device, the directional controllability of the diffuser can be patterned across the display, allowing for spatially varying diffusion directional properties.

[0280] Another additional exemplary device according to some embodiments can include a diffuser configured to change the direction of diffusion of a light beam upon application of a voltage to the diffuser.

[0281] Some embodiments of another additional exemplary apparatus may include a light field display structure configured to generate one or more collimated light beams incident on a diffuser.

[0282] Another additional exemplary method according to some embodiments may include changing the direction of diffusion of a light beam upon application of a voltage to a diffuser.

[0283] Another additional exemplary device according to some embodiments can include a diffuser configured to change the shape of a light beam upon application of a voltage to the diffuser.

[0284] Another additional exemplary method according to some embodiments may include changing the shape of a light beam upon application of a voltage to a diffuser.

[0285] Another additional exemplary device according to some embodiments can include a diffuser configured to change the angle of divergence of a light beam upon application of a voltage to the diffuser.

[0286] Another additional exemplary method according to some embodiments may include changing the angle of divergence of the light beam upon application of a voltage to the diffuser.

[0287] Another additional exemplary device according to some embodiments can include a diffuser configured to redirect a light beam upon application of a voltage to the diffuser.

[0288] Another additional exemplary method according to some embodiments may include redirecting a light beam upon application of a voltage to a diffuser.

[0289] Another additional exemplary device according to some embodiments may include a liquid crystal grating configured to spread a light beam into two or more spread light beams.

[0290] Another additional exemplary method according to some embodiments may include diverging a light beam into two or more diverged light beams upon application of a voltage to a liquid crystal grating.

[0291] Another additional exemplary device according to some embodiments can include a diffuser configured to diffuse light in a single coordinate plane.

[0292] Another additional exemplary method according to some embodiments may include diffusing light in a single coordinate plane.

[0293] Another additional exemplary device according to some embodiments may include a diffuser configured to receive a selected selection from the group consisting of a horizontal plane and a vertical plane and to diffuse light only within the selected plane.

[0294] Another additional exemplary method according to some embodiments may include receiving a selected selection from the group consisting of a horizontal plane and a vertical plane, and diffusing light only within the selected plane.

[0295] A multi-view three-dimensional optical display device according to some embodiments may include a selective directional diffuser configured to be selectively activated without mechanical movement, the selective directional diffuser including at least one surface effect liquid crystal (SELC) diffuser configured to receive one or more linearly polarized and collimated beams of light and diffuse them in selective directions in response to an applied electric field.

[0296] An exemplary device according to some embodiments may include a display, a first controllable diffuser overlying the display, the first controllable diffuser selectively operable to diffuse light in a first direction, and a second controllable diffuser overlying the display, the second controllable diffuser selectively operable to diffuse light in a second direction substantially perpendicular to the first direction.

[0297] For some embodiments of the exemplary device, the display can be a multi-view display.

[0298] For some embodiments of the exemplary apparatus, at least one of the first controllable diffuser and the second controllable diffuser may include a surface effect liquid crystal (SELC) diffuser.

[0299] For some embodiments of the exemplary device, the SELC diffuser may include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and at least one of the LC material layer and the first and second substrates may be configured to perform angle-selective diffusion of light.

[0300] For some embodiments of the exemplary device, the device may include at least one liquid crystal (LC) diffraction grating.

[0301] For some embodiments of the exemplary apparatus, at least one of the at least one LC diffraction grating and the first and second controllable diffusers may include a birefringent material.

[0302] Some embodiments of the exemplary device may further include a sensor configured to detect an orientation of the display, and the device may be configured to switch between selectively operating the first controllable diffuser to diffuse in a first direction and selectively operating the second controllable diffuser to diffuse in a second direction in response to a detected change in orientation of the display.

[0303] For some embodiments of the exemplary device, at least one of the first controllable diffuser and the second controllable diffuser can be configured to be selectively activated without mechanical movement.

[0304] For some embodiments of the exemplary apparatus, at least one of the first controllable diffuser and the second controllable diffuser can be configured to diffuse light in response to an applied electric field.

[0305] An exemplary optical element according to some embodiments can include a first layer comprising electrically tunable liquid crystals capable of changing the polarization state of light passing through the first layer depending on the state of the electrical tuning; and a second layer comprising birefringent material in a layer parallel to the first layer including surface structures designed to impart alternating diffusion properties to the beam, wherein the second layer can be configured to scatter light incident on the second layer according to a first angular pattern when the polarization state of the light is in a first polarization state, and the second layer can be configured to scatter light incident on the second layer according to a second angular pattern when the polarization state of the light is in a second polarization state.

[0306] For some embodiments of the exemplary optical element, the second layer can be configured to diffuse light in a horizontal direction when the polarization state of the light is in a first polarization state, and the second layer can be configured to diffuse light in a vertical direction when the polarization state of the light is in a second polarization state.

[0307] Some embodiments of the exemplary device may further include a plurality of light emitting elements and collimating microlenses capable of generating a collimated beam of light, and a directionally controllable diffuser capable of switching between a first state in which the light is diffused in a first direction and a second state in which the light is diffused in a second direction.

[0308] For some embodiments of the exemplary optical element, the directionally controllable diffuser can be configured to diffuse in the vertical direction, and the device can be configured such that when the device is in portrait orientation, only a single vertical view is produced.

[0309] For some embodiments of the exemplary optical element, at least some of the plurality of light-emitting elements may be arranged in a plus-shaped pattern.

[0310] For some embodiments of the exemplary optical element, in response to rotation of the device, the direction-controllable diffuser can be enabled to diffuse in the rotated direction, and the device can be configured such that when the display orientation is changed from portrait to landscape, only a single view is generated in the direction of diffusion.

[0311] Some embodiments of the exemplary device may further include a three-dimensional (3D) display, and the directional controllability of the diffuser may be patterned across the 3D display, allowing for spatially varying diffusion directional properties.

[0312] An exemplary method according to some embodiments may include emitting a light beam from one or more light-emitting devices, polarizing the light beam into a linearly polarized beam, passing the light beam through a liquid crystal (LC) material, passing the light beam through a birefringent material, and applying a voltage to the LC material to change the light polarization configuration state of the LC material, where changing the light polarization configuration state switches from a first polarization state to a second polarization state, the first polarization state diffusing the light beam in a first direction when passing through the birefringent material, and the second polarization state diffusing the light beam in a second direction when passing through the birefringent material.

[0313] Some embodiments of the exemplary method may further comprise rendering one or more images for a light field (LF) display device and sending the one or more rendered images to the LF display device.

[0314] Some embodiments of the example method may further comprise receiving a field of view (FOV) selection for the LF display device.

[0315] Some embodiments of the example method may further comprise adjusting the brightness of the emitted light beam based on the FOV selection.

[0316] An exemplary apparatus according to some embodiments can include an array of light-emitting devices, a polarizer layer, a microlens array (MLA), one or more diffusers, and one or more diffraction gratings.

[0317] For some embodiments of the exemplary apparatus, the array of light-emitting devices may include one or more sets of light-emitting devices.

[0318] For some embodiments of the exemplary apparatus, each of the one or more sets of light-emitting devices can include a pixel.

[0319] Some embodiments of the example method may further include a backboard and one or more baffles, wherein the array of one or more sets of light-emitting devices is mounted on the backboard, each set of light-emitting devices in the array corresponding to a respective baffle, each baffle at least partially separating each set of light-emitting devices from the remainder of the array of one or more sets of light-emitting devices.

[0320] For some embodiments of the exemplary apparatus, at least one of the one or more diffusers may be configured to diffuse light emitted by at least one of the light-emitting devices in a horizontal direction, and at least one of the one or more diffusers may be configured to diffuse light emitted by at least one of the light-emitting devices in a vertical direction.

[0321] For some embodiments of the exemplary apparatus, at least one of the one or more diffusers can be configured to switch between diffusing light emitted by at least one of the light-emitting devices in a horizontal direction and diffusing light in a vertical direction.

[0322] For some embodiments of the exemplary device, at least one of the one or more diffusers can be a surface effect liquid crystal (SELC) diffuser.

[0323] For some embodiments of the exemplary device, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and the LC material layer can be configured to cooperate with the first substrate and the second substrate to cause angle-selective diffusion of light in response to an applied voltage.

[0324] For some embodiments of the exemplary device, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and the LC material layer and the first and second substrates can have selected material properties that work in conjunction to scatter a light beam.

[0325] For some embodiments of the exemplary device, at least one of the diffusers can be configured to switch between a 2D display mode and a 3D display mode.

[0326] For some embodiments of the exemplary device, a first one of the diffusers can be a SELC diffuser configured to scatter light displaying a first image using a first diffusion direction, and a second one of the diffusers can be a SELC diffuser configured to scatter light displaying a second image using a second diffusion direction, and the first diffusion direction can be orthogonal to the second diffusion direction.

[0327] For some embodiments of the exemplary apparatus, at least one of the diffusers can be a SELC diffuser configured to diffuse light to reduce glare on the image projected by the array of light-emitting devices.

[0328] For some embodiments of the exemplary device, at least one of the gratings can include a liquid crystal material.

[0329] For some embodiments of the exemplary device, at least one of the diffraction gratings can include a birefringent material.

[0330] For some embodiments of the exemplary apparatus, at least one of the one or more diffusers can be configured as a mosaic diffuser to together diffuse one or more neighboring light beams emitted by one or more of the light-emitting devices.

[0331] It should be noted that one or more of the various hardware elements of the described embodiments are referred to as “modules,” which perform (i.e., execute, perform, etc.) various functions described herein in connection with the respective module. As used herein, a module includes hardware deemed appropriate by one of ordinary skill in the relevant art for a given implementation (e.g., one or more processors, one or more microprocessors, one or more microcontrollers, one or more microchips, one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), one or more memory devices). It should be noted that each described module may also include executable instructions for performing one or more functions described as being performed by the respective module, which may take the form of or include hardware (i.e., hardwired) instructions, firmware instructions, and / or software instructions, etc., and may be stored in any suitable non-transitory computer-readable medium or media, such as commonly referred to as RAM, ROM, etc.

[0332] Although features and elements have been described above in particular combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein can be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer. [Industrial Applicability]

[0333] The present invention can be used in displays.

Claims

1. a multi-view display configured to project a light beam, the projected light beam imaging each pixel of a displayed image viewable from one of a plurality of view directions; a plurality of controllable diffusers, each configured to selectively diffuse at least one of the projected light beams according to a respective diffusion pattern, arranged overlapping one another in a light transmission direction; A device comprising:

2. The multi-view display includes an array of projection cells, each projection cell in the array having: a source module configured to emit light from one or more light-emitting elements; a polarizer component configured to linearly polarize the emitted light; and a microlens configured to collimate the polarized light into a collimated light beam; Equipped with 2. The apparatus of claim 1, wherein the collimated light beam originating from the light-emitting element of the source module corresponds to a view direction of a pixel of the displayed image.

3. at least one of the plurality of controllable diffusers is a surface effect liquid crystal diffuser (SELC diffuser) including a liquid crystal layer (LC layer) having an optical interface to a substrate; 10. The device of claim 1, wherein the refractive index of the LC layer depends on the polarization state of light passing through the LC layer, the polarization state being induced by applying an electric field to the LC layer.

4. in a first mode of operation, the SELC diffuser is configured to scatter passing light when the passing light is in a polarization state corresponding to a refractive index of the LC layer that is different from the refractive index of the substrate; 4. The device of claim 3, wherein in a second mode of operation, the SELC diffuser is configured not to scatter the passing light when the passing light is in a polarization state corresponding to a refractive index of the LC layer that is substantially the same as the refractive index of the substrate.

5. 5. The apparatus of claim 4, wherein the optical interface includes microstructures, and when the SELC diffuser operates in the first mode, passing light is scattered in a direction according to the orientation of the microstructures.

6. 5. The apparatus of claim 4, wherein the optical interface includes a microstructure, and when the SELC diffuser operates in the first mode, passing light is scattered with a divergence angle according to a surface slope distribution of the microstructure.

7. 10. The apparatus of claim 1, wherein one or more of the plurality of controllable diffusers comprises a liquid crystal grating (LC grating) configured to enhance the diffusion of the at least one projected light beam.

8. The device of claim 7 , wherein the LC grating comprises a birefringent material.

9. The apparatus of claim 1 , wherein at least one of the plurality of controllable diffusers comprises a birefringent material.

10. a sensor configured to detect an orientation of the multi-view display; 10. The device of claim 1, configured to switch between selectively operating the plurality of controllable diffusers to diffuse according to a diffusion pattern in a first direction and selectively operating the plurality of controllable diffusers to diffuse according to a diffusion pattern in a second direction substantially perpendicular to the first direction in response to a detected change in the orientation of the multi-view display.

11. A method of displaying a multi-view image, comprising: projecting a light beam from a multi-view display, the projected light beam imaging each pixel of a displayed image viewable from one of a plurality of view directions; selectively operating a plurality of controllable diffusers according to respective diffusion patterns to diffuse at least one of the projected light beams, the controllable diffusers being arranged so as to overlap one another in a light transmission direction; A method for providing the above.

12. the multi-view display includes an array of projection cells; The step of projecting the light beam from the multi-view display comprises: emitting light from the light-emitting element of the source module; linearly polarizing the emitted light by a polarizer component; and collimating the polarized light into a collimated light beam by a microlens, the collimated light beam corresponding to a view direction of a pixel of the displayed image; 12. The method of claim 11, comprising projecting a light beam from a projection cell in the array.

13. at least one of the plurality of controllable diffusers is a surface effect liquid crystal diffuser (SELC diffuser) including a liquid crystal layer (LC layer) having an optical interface to a substrate; Selective diffusion is 12. The method of claim 11, comprising applying an electric field to the LC layer to induce a polarization state of light passing therethrough, the refractive index of the LC layer being dependent on the induced polarization state.

14. operating the SELC diffuser in a first mode of operation, the SELC diffuser being configured to scatter light passing therethrough when the light is in a polarization state corresponding to a refractive index of the LC layer that is different from the refractive index of the substrate; operating the SELC diffuser in a second mode of operation, wherein the SELC diffuser is configured not to scatter the passing light when the passing light is in a polarization state corresponding to a refractive index of the LC layer that is substantially the same as the refractive index of the substrate; and The method of claim 13 further comprising:

15. 15. The method of claim 14, wherein the optical interface includes microstructures, and when the SELC diffuser operates in the first mode, passing light is scattered in a direction according to the orientation of the microstructures.

16. 15. The method of claim 14, wherein the optical interface includes a microstructure, and when the SELC diffuser operates in the first mode, passing light is scattered at a divergence angle according to a surface slope profile of the microstructure.

17. one or more of the plurality of controllable diffusers comprises a liquid crystal grating (LC grating); using the LC diffraction grating to enhance the diffusion of the at least one projected light beam. The method of claim 11 further comprising:

18. The method of claim 17 , wherein the LC grating comprises a birefringent material.

19. The method of claim 11 , wherein at least one of the plurality of controllable diffusers comprises a birefringent material.

20. detecting an orientation of the multi-view display; responsive to the detected change in orientation of the multi-view display, switching between selectively operating the plurality of controllable diffusers to diffuse according to a diffusion pattern in a first direction and selectively operating the plurality of controllable diffusers to diffuse according to a diffusion pattern in a second direction substantially perpendicular to the first direction; The method of claim 11 further comprising:

Images