Apparatus and method for light field display

Abstract

An apparatus and method for a light field display are disclosed. The apparatus includes: a display configured to project a light beam; and a plurality of controllable diffusers, each controllable diffuser configured to selectively diffuse at least one of the projected light beams according to a respective diffusion pattern.

Description

[0001] This application is a divisional application of the invention patent application with the application date of June 24, 2020, application number 202080056500.0, and invention name “Light field display device and method performed by light field display device”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is a non-provisional application of U.S. Provisional Patent Application Serial No. 62 / 868,687, filed on June 28, 2019, entitled “OPTICAL METHOD AND SYSTEM FOR LIGHTFIELD (LF) DISPLAYS BASED ON TUNABLE LIQUID CRYSTAL (LC) DIFFUSERS,” and claims the benefit of the U.S. Provisional Patent Application under 35 U.S.C. §119(e), which is hereby incorporated by reference in its entirety. Technical Field

[0004] The present application relates to the field of optics. Background Art

[0005] The human brain senses and determines the depth of the object being viewed, in part, by receiving signals from muscles that determine the orientation of each eye. The brain associates the relative angular orientation of the eye with the determined depth of focus. Correct focus cues produce natural blur on objects outside the observed focal plane and produce natural dynamic parallax effects. A type of 3D display that can provide correct focus cues uses a volumetric display technology that can produce 3D images in real 3D space. Each "voxel" of the 3D image is physically located at a spatial position and reflects or emits light from that position toward the observer to form a real image in the viewer's eyes. Some problems with 3D volumetric displays are their low resolution, large physical size, and high manufacturing costs. These problems may make them too cumbersome to use outside of, for example, product displays, museums, and exhibitions. Summary of the invention

[0006] According to some embodiments, a device is disclosed that includes: a display configured to project a light beam; and a plurality of controllable diffusers, each controllable diffuser configured to selectively diffuse at least one of the projected light beams according to a corresponding diffusion pattern.

[0007] According to some embodiments, a method is disclosed that includes: projecting light beams from a display; and selectively operating a plurality of controllable diffusers to diffuse at least one of the projected light beams according to a corresponding diffusion pattern.

[0008] An exemplary device according to some embodiments may include: a display; a first controllable diffuser covering the display, the first controllable diffuser being selectively operable to diffuse light in a first direction; and a second controllable diffuser covering the display, the second controllable diffuser being selectively operable to diffuse light in a second direction substantially perpendicular to the first direction.

[0009] For some embodiments of the example apparatus, the display may be a multi-view display.

[0010] For some embodiments of the example apparatus, at least one of the first controllable diffuser and the second controllable diffuser may include a surface effect liquid crystal (SELC) diffuser.

[0011] For some embodiments of the example 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, the first substrate, and the second substrate may be configured to perform angle-selective diffusion of light.

[0012] For some embodiments of the exemplary devices, the device may include at least one liquid crystal (LC) grating.

[0013] For some embodiments of the exemplary apparatus, at least one of the at least one LC grating, the first controllable diffuser, and the second controllable diffuser may include a birefringent material.

[0014] Some embodiments of the exemplary apparatus may further include a sensor configured to detect an orientation of the display, and the apparatus 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 detecting a change in the orientation of the display.

[0015] For some embodiments of the example apparatus, at least one of the first controllable diffuser and the second controllable diffuser may be configured to be selectively activated without mechanical movement.

[0016] For some embodiments of the example apparatus, at least one of the first controllable diffuser and the second controllable diffuser may be configured to diffuse light in response to an applied electric field.

[0017] An exemplary optical element according to some embodiments may include: a first layer, which includes an electrically adjustable liquid crystal capable of changing the polarization state of light passing through the first layer according to a state of electrical adjustment; and a second layer, which includes a birefringent material in a layer parallel to the first layer, the birefringent material including a surface structure designed to provide alternating diffusion properties to the light beam, so that 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.

[0018] 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.

[0019] Some embodiments of the exemplary device may also include: a plurality of light emitting elements and a collimating microlens capable of producing a collimated light beam; and a directionally controllable diffuser capable of switching between a first state and a second state, in which the light is diffused in a first direction and in which the light is diffused in a second direction.

[0020] For some embodiments of the exemplary optical element, the directionally controllable diffuser can be configured to diffuse in a vertical direction, and the device can be configured such that only a single vertical view is generated if the device is in a portrait orientation.

[0021] For some embodiments of the exemplary optical element, at least a portion of the plurality of light emitting elements may be arranged in a plus-sign shaped pattern.

[0022] For some embodiments of the exemplary optical element, in response to rotation of the device, the directionally controllable diffuser can be enabled to diffuse in the rotational direction, and the device can be configured so that if the display orientation changes from portrait to landscape, only a single view is generated in the diffusion direction.

[0023] Some embodiments of the exemplary apparatus may also include a three-dimensional (3D) display, such that the directional controllability of the diffuser may be patterned on the 3D display, thereby allowing for spatially varying diffuse directional characteristics.

[0024] Exemplary methods 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 light 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 a light polarization configuration state of the LC material, so that the light polarization configuration state is changed to switch from a first polarization state to a second polarization state, and so that the first polarization state causes the light beam to diffuse in a first direction when passing through the birefringent material, and the second polarization state causes the light beam to diffuse in a second direction when passing through the birefringent material.

[0025] Some embodiments of the example 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.

[0026] Some embodiments of the example method may also include receiving a field of view (FOV) selection for the LF display device.

[0027] Some embodiments of the exemplary method may also include adjusting the brightness of the emitted light beam based on the FOV selection.

[0028] An exemplary apparatus according to some embodiments may include: an array of light emitting devices; a polarizing layer; a microlens array (MLA); one or more diffusers; and one or more gratings.

[0029] For some embodiments of the example apparatus, the array of light emitting devices may include one or more groups of light emitting devices.

[0030] For some embodiments of the example apparatus, each light emitting device in the one or more groups of light emitting devices may include a pixel.

[0031] Some embodiments of the exemplary method may also include: a back panel; and one or more baffles, so that the array of one or more groups of light-emitting devices is mounted to the back panel, so that each group of light-emitting devices in the array corresponds to a corresponding baffle, and each baffle at least partially separates the corresponding group of light-emitting devices from the rest of the array of one or more groups of light-emitting devices.

[0032] 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.

[0033] For some embodiments of the example 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 emitted by at least one of the light emitting devices in a vertical direction.

[0034] For some embodiments of the example apparatus, at least one of the one or more diffusers may be a surface effect liquid crystal (SELC) diffuser.

[0035] For some embodiments of the example device, the SELC diffuser may include a liquid crystal (LC) material layer sandwiched between first and second substrates, which LC material layer may be configured to cause angle-selective diffusion of light in response to an applied voltage in conjunction with the first and second substrates.

[0036] 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 the LC material layer, the first substrate, and the second substrate may have selected materials and interface surface properties that work together to scatter the light beam.

[0037] For some implementations of the example apparatus, at least one of the diffusers is configured to switch between a 2D display mode and a 3D display mode.

[0038] For some embodiments of the example device, a first SELC diffuser among the diffusers may be a SELC diffuser configured to scatter light displaying a first image using a first diffusion direction, a second SELC diffuser among the diffusers may be a SELC diffuser configured to scatter light displaying a second image using a second diffusion direction, and the first diffusion direction may be orthogonal to the second diffusion direction.

[0039] For some embodiments of the example apparatus, at least one of the diffusers may be a SELC diffuser configured to diffuse light to reduce glare of an image projected by the array of light emitting devices.

[0040] For some embodiments of the exemplary apparatus, at least one of the gratings may include a liquid crystal material.

[0041] For some embodiments of the exemplary apparatus, at least one of the gratings may include a birefringent material.

[0042] For some embodiments of the example apparatus, at least one of the one or more diffusers can be configured as a mosaic diffuser to diffuse together one or more adjacent light beams emitted by one or more of the light emitting devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1A is a system diagram illustrating an exemplary communication system according to some embodiments.

[0044] Figure 1B is a diagram showing that according to some embodiments, Figure 1A A system diagram of an exemplary wireless transmit / receive unit (WTRU) for use within a communication system is shown.

[0045] Figure 2 is a diagram showing an exemplary handheld display in a first configuration according to some embodiments.

[0046] Figure 3A is a diagram showing an exemplary handheld display in a second configuration according to some embodiments.

[0047] Figure 3B is a diagram showing an exemplary handheld display in a third configuration according to some embodiments.

[0048] Figure 4A is a diagram showing an exemplary multi-view 3D display in a first configuration according to some embodiments.

[0049] Figure 4B is a diagram showing an exemplary multi-view 3D display in a second configuration according to some embodiments.

[0050] Figure 4C is a diagram showing an exemplary multi-view 3D display in a third configuration according to some embodiments.

[0051] Figure 5 is a diagram showing an exemplary 3D light field display with image areas on both sides of the device according to some embodiments.

[0052] Fig. 6A is a diagram showing an exemplary 3D light field display with an exemplary small viewing area according to some embodiments.

[0053] Figure 6B is a diagram showing an exemplary 3D light field display with an exemplary large viewing area according to some embodiments.

[0054] Fig. 7A is a diagram illustrating an exemplary ideal case of perfect collimation without any beam divergence caused by one or more geometric factors, according to some embodiments.

[0055] Figure 7Bis a diagram illustrating exemplary beam divergence caused by one or more geometric factors according to some embodiments.

[0056] Figure 7C is a diagram illustrating exemplary beam divergence caused by one or more geometric factors according to some embodiments.

[0057] Fig.7D is a diagram showing an exemplary beam divergence and a first aperture size caused by diffraction according to some embodiments.

[0058] Fig. 7E is a diagram showing an exemplary beam divergence and a second aperture size due to diffraction according to some embodiments.

[0059] Figure 7F is a diagram showing an exemplary beam divergence and a third aperture size due to diffraction according to some embodiments.

[0060] Fig. 8A is a diagram illustrating an exemplary image magnification lens having a first optical power according to some embodiments.

[0061] Figure 8B is a diagram illustrating an exemplary image magnification lens having a second optical power according to some embodiments.

[0062] Figure 8C is a diagram illustrating an exemplary image magnification lens having a third optical power according to some embodiments.

[0063] Fig. 9A is a diagram showing an exemplary first light source and lens configuration according to some embodiments.

[0064] Fig. 9B is a diagram showing an exemplary second light source and lens configuration according to some embodiments.

[0065] Fig. 9C is a diagram showing an exemplary third light source and lens configuration according to some embodiments.

[0066] Fig.9D is a diagram illustrating an exemplary fourth light source and lens configuration according to some embodiments.

[0067] Fig.10 is a diagram illustrating an exemplary variable focal length microlens array according to some embodiments.

[0068] Fig.11A is a diagram showing an exemplary two-component SELC diffuser in a beam-transmitting state according to some embodiments.

[0069] Fig. 11B is a diagram showing an exemplary two-component SELC diffuser in a beam diffusing state according to some embodiments.

[0070] Fig. 12A is a diagram showing an exemplary single-component SELC diffuser in a beam-transmitting state according to some embodiments.

[0071] Fig. 12B is a diagram showing an exemplary single-component SELC diffuser in a beam diffusing state according to some embodiments.

[0072] Fig.13A is a diagram showing an exemplary SELC diffuser with a smaller divergence angle according to some embodiments.

[0073] Fig. 13B is a diagram showing an exemplary SELC diffuser with a larger divergence angle according to some embodiments.

[0074] Fig.14A is a diagram showing an exemplary SELC diffuser with horizontal diffusion enabled according to some embodiments.

[0075] Fig. 14B is a diagram showing an exemplary SELC diffuser with vertical diffusion enabled according to some embodiments.

[0076] Fig.15 is a diagram showing an exemplary 3D light field optical display structure according to some embodiments.

[0077] Fig.16A is a diagram showing an exemplary light emitter matrix layout for a full-color image with four sub-pixels per full-color light beam according to some embodiments.

[0078] Fig. 16B is a diagram showing an exemplary light emitter matrix layout for a full-color image with three sub-pixels per full-color light beam according to some embodiments.

[0079] Fig.17 is a schematic perspective view showing an exemplary 3D display in portrait mode and landscape mode according to some embodiments.

[0080] Fig.18 is a diagram showing an exemplary 3D display structure with a tunable LC grating according to some embodiments.

[0081] Fig.19 is a schematic perspective view illustrating an exemplary mobile device viewing configuration according to some embodiments.

[0082] Fig. 20is a diagram showing an exemplary μLED pattern layout according to some embodiments.

[0083] Fig.21 is a diagram illustrating an exemplary display optical device structure according to some embodiments.

[0084] Fig.22A is a diagram showing an exemplary simulated irradiance distribution without a diffuser according to some embodiments.

[0085] Fig. 22B is a diagram showing an exemplary simulated irradiance distribution with a SELC diffuser according to some embodiments.

[0086] Fig. 22C is a diagram showing an exemplary simulated irradiance distribution with a SELC diffuser and a grating according to some embodiments.

[0087] Fig.22D is a diagram showing an exemplary simulated irradiance distribution with a horizontal diffuser and a vertical diffuser activated according to some embodiments.

[0088] Fig.23 is a graph showing an exemplary horizontal irradiance distribution for a deactivated horizontal diffuser and grating according to some embodiments.

[0089] Fig.24 is a graph showing exemplary vertical irradiance distributions for three configurations according to some embodiments.

[0090] Fig.25 is a graph showing exemplary irradiance distribution for a row of horizontal light sources with a horizontal diffuser, a vertical diffuser, and a grating according to some embodiments.

[0091] Fig.26 is a message timing diagram illustrating an exemplary process for processing and displaying 3D images according to some embodiments.

[0092] Fig. 27 is a flow chart illustrating an exemplary process for processing and rendering 3D images according to some embodiments.

[0093] Fig.28 is a flow chart illustrating an exemplary process for processing and rendering 3D images according to some embodiments.

[0094] The entities, connections, arrangements, etc. shown in and described in connection with the various figures are presented by way of example and not by way of limitation. Therefore, any and all statements or other indications as to what a particular figure "depicts," what a particular element or entity in a particular figure "is" or "has," and any and all similar states that may be read in isolation and out of context as absolute and therefore limiting, may be read only as appropriately in a constructive manner with a clause such as "in at least one embodiment, ..." For the sake of brevity and clarity of presentation, this implicit leading clause is not repeated in the detailed description. DETAILED DESCRIPTION

[0095] In some embodiments described herein, a wireless transmit / receive unit (WTRU) may be used as, for example, a light field display device.

[0096] Figure 1A 1 is a schematic diagram illustrating an exemplary 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 multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ 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 tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0097] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the 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), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0098] The communication 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 that is configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, 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 eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0099] 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), a relay node, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0100] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an 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).

[0101] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 116. 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).

[0102] In one 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 Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0103] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0104] In one 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 implement LTE radio access and NR radio access together, for example using dual connectivity (DC) principles. Thus, the air interface used 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).

[0105] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., 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), GSM Enhanced Data Rates for Evolution (EDGE), GSM EDGE (GERAN), etc.

[0106] Figure 1AThe base station 114b in the 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 local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio 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 utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, the base station 114 b may have a direct connection to the Internet 110. Therefore, the base station 114 b may not need to access the Internet 110 via the CN 106.

[0107] The RAN 104 / 113 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the specification, the CN 106 may be configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 may be in direct or indirect communication with other RANs that employ 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 be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0108] The CN 106 may also act 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 that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0109] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication 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 via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0110] Figure 1B is a system diagram illustrating an exemplary WTRU 102. Figure 1B As shown, 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 appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0111] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated 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 functions that enable 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. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0112] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive RF and light signals. It should be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0113] Although the transmit / receive element 122 is Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ 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.

[0114] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted 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 NR and IEEE 802.11.

[0115] The processor 118 of the WTRU 102 may be coupled to 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) and may receive user input data therefrom. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a 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, and the like. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0116] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to other components in 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 cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0117] The processor 118 may also be coupled to the 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 in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or 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 by any suitable location-determination method while remaining consistent with an embodiment.

[0118] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules 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 electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, 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 peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0119] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0120] Given that Figure 1A to Figure 1B as well as Figure 1A to Figure 1B Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRUs 102a-d, base stations 114a-b, and / or any other devices described herein. The simulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the simulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0121] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, the one or more simulation devices may perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. The one or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0122] The one or more simulation devices may perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device may be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. The one or more simulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which may include one or more antennas) may be used by the simulation device to transmit and / or receive data.

[0123] Many previous 3D displays can be classified into four exemplary categories based on their form factors: head mounted display devices (HMDs), volumetric 3D displays, screen-based 3D displays, and holographic displays. The exemplary categories are for explanation only, and, for example, in some cases, the examples may overlap.

[0124] Many head-mounted devices (HMDs) take up less space than goggle-free devices and can be manufactured with smaller parts and less material, which understandably translates to relatively lower costs. However, because head-mounted VR goggles and smart glasses are single-user devices, such devices do not allow for a shared experience as naturally as goggle-free solutions.

[0125] Volumetric 3D displays occupy space from all three spatial directions and may require a large amount of physical materials that make many such devices bulky, expensive to manufacture, and difficult to transport. Due to the large amount of material used, volumetric displays also tend to have a small "window" and a limited field of view (FOV).

[0126] Screen-based 3D displays typically have a large but flat screen and a device that projects the image from a distance onto free space. These devices may be made more compact for transport and have a larger FOV than, for example, volumetric displays. Many of these devices are complex and expensive and require a projector subassembly. Many such devices also require, for example, accurate alignment between different components. Flat form factor 3D displays may require a lot of space in two spatial directions, but since the third direction is only virtual, such devices may be relatively easy to transport to and assemble in different environments. Because these devices are flat, some of the optical components may be manufactured in sheets or rolls, making these devices relatively low cost when produced in large quantities.

[0127] Another type of 3D display device that can provide the correct retinal focus cues is a holographic display. A holographic display aims to reconstruct the entire light wavefront scattered from objects in the natural environment. Many such devices lack suitable spatial light modulator (SLM) components that can be used to generate extremely detailed wavefronts.

[0128] Light field (LF) displays are referred to as another type of 3D display technology that can provide natural retinal focus cues. LF display systems can generally be designed to produce a so-called light field, which represents that light is propagated to all directions in space. LF systems may generally be intended to control light emission in both spatial and angular domains with high resolution. 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 can all be included as some examples of LF displays.

[0129] In many relatively low-density multi-view imaging displays, the view changes in a rough and step-by-step manner when the viewer moves in front of the device. This characteristic reduces the quality of the 3D experience and may even lead to a complete breakdown of 3D perception. In order to alleviate this problem (as well as problems of the type of visual convergence adjustment conflict (VAC)), some super-multi-view (SMV) techniques have been tested with up to 512 views. Generate a very large number of views so that any transition between two viewpoints is very smooth. If light from at least two images from slightly different viewpoints enters the pupil of the eye at the same time, a more realistic visual experience will be produced. In this case, the motion parallax effect is closer to natural conditions because the brain unconsciously predicts image changes due to motion. The SMV condition can be met by reducing the interval between the two views at the correct viewing distance to a value less than the size of the pupil of the eye. Under normal lighting conditions, the diameter of the human pupil is generally estimated to be about 4mm. If the ambient light level is high (for example, in sunlight), the diameter can be as small as 1.5mm and as large as 8mm in dark conditions. The maximum angular density achievable with SMV displays is limited by diffraction, and there is an inverse relationship between spatial resolution (pixel size) and angular resolution. Diffraction increases the angular spread of the beam passing through the aperture, and this effect may often need to be considered in the design of very high density SMV displays.

[0130] For some embodiments, a tunable diffuser component capable of angularly selective light diffusion enables modification of the beam angle divergence characteristics without moving components. Such a diffuser may have a component based on the light scattering effect of the optical interface surface. For a specific field of view, some embodiments of a 3D optical display structure with a surface effect liquid crystal (SELC) tunable diffuser may have a smaller number of light-emitting components than other devices. For some embodiments, light is emitted from individually controllable small emitters and collimated with a microlens array. SELC is used to selectively diffuse the emitted light beam when the orientation of the view direction is switched. For some embodiments, such a diffuser may be manufactured with a smaller number of emitters and manufactured at a lower cost than other devices.

[0131] There are so-called "smart windows" that can be transmissive and transparent, e.g., in the power-on state, and opaque, e.g., in the power-off state. LC diffusers based on volume scattering have been used in display technology, such as polymer stabilized liquid crystals (PSLC) or polymer dispersed liquid crystals (PDLC) used in transparent displays or smart glasses. Conventional methods are known to be fully transmissive or have no angle-dependent light diffusion in many cases.

[0132] There are exemplary static light direction controllers and static light shaping diffusers with fixed angular performance. Angular control of the diffusion effect can be used with displays. For example, Luminit is known to have produced directional turning films (DTFs) and light shaping diffusers (LSDs) that are static devices with fixed angular performance. The directional characteristics are fixed at the time of manufacture.

[0133] Figure 2 is a diagram showing an exemplary handheld display in a first configuration according to some embodiments. Figure 2 A handheld display and images seen by three viewers are shown. At a first power level, wide diffusion (e.g., 180 degrees) in all directions can be used for general multi-user viewing of images. FOV 202 is, for example, 180 degrees, and all viewers 204, 206, 208 see the image.

[0134] Figure 3A is a diagram showing an exemplary handheld display in a second configuration according to some embodiments. Figure 3A A reduced FOV 302 (eg, 80 degrees) but brighter image is shown, where only a single viewer 304 sees the brighter image. For some embodiments, a handheld display may use controllable FOV reduction to save power in exchange for the FOV reduction.

[0135] Figure 3Bis a diagram showing an exemplary handheld display in a third configuration according to some embodiments. Figure 3A compared to, Figure 3B A reduced FOV 352 (e.g., 80 degrees) but lower brightness levels are shown. Figure 3A Same, only one viewer 354 saw Figure 3B For some embodiments, a moderate level of diffusion may be used to provide a reduced field of view and achieve power savings by reducing the emitted light in accordance with the reduced FOV, without reducing the brightness seen by the primary viewer.

[0136] Multi-view LF displays can be based solely on spatial multiplexing. Rows or matrices of luminous pixels (display sub-pixels) can be located behind a lenticular lens sheet or microlens array, and each pixel can project to a unique view direction or a limited set of view directions in front of the display structure. The more pixels on the luminous layer behind each beam collimating feature structure, the more views can be generated. This phenomenon may lead to a trade-off between spatial resolution and the number of unique views generated. If the 3D display generates a smaller LF pixel size, the size of the individual sub-pixels can be reduced and / or a smaller number of viewing directions can be generated. Due to the lack of suitable components, the sub-pixel size may be limited to a relatively large area. High-quality LF displays can have both high spatial resolution and high angular resolution. High angular resolution may be required to meet super-multi-view (SMV) conditions, and this high angular resolution may be very difficult to achieve with currently available sources.

[0137] Figure 4A is a diagram showing an exemplary multi-view 3D display structure with a first focal length according to some embodiments. Figure 4B is a diagram showing an exemplary multi-view 3D display structure with a second focal length according to some embodiments. Figure 4C is a diagram showing an exemplary multi-view 3D display structure with a third focal length according to some embodiments.

[0138] As an example of an optical design problem, Figure 4A and Figure 4B Two panoramic imaging multi-view display examples are shown, where a lenticular sheet is placed in front of an array of light emitters. Figure 4A and Figure 4B In the example, the number and size of the emitters are the same. The biconvex 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 optics of the biconvex lenses can be capable of producing multiple apertures of light collimated into separate beams that are used to display multi-view images to different view directions. Both exemplary cases have the same field of view (FOV) 406, 436, but when Figure 4B The structure has a larger lens aperture 434 covering five sources with five shown views 438, 440, 442, 444, 446, rather than having Figure 4A The angular resolution is higher when the lens aperture 404 covers three sources with three shown views 408, 410, 412. However, the spatial resolution is lower when the aperture is larger.

[0139] A similar tradeoff can be made using angular view density and total angular range or FOV. By increasing the distance between the microlens and the emitter and correspondingly reducing the optical power of the microlens, the angular view density can be increased but the FOV can be reduced. This tradeoff is Figure 4B and Figure 4C Both structures have the same lens aperture size 464, 434, and both structures are able to produce five different view beams 438, 440, 442, 444, 446, 468, 470, 472, 474, 476 for each projector unit. However, when Figure 4C When the optical device of the structure has a longer FL 462, the light beams 468, 470, 472, 474, 476 are projected into a smaller FOV 466 and the angular density increases.

[0140] LF displays based on panoramic imaging have spatial and angular domains, where multiple interlaced beams are used together to produce multiple different images. In order to meet the field of view and image uniformity requirements of optical display structures, light diffusing surfaces are generally required. Diffuser structures can be used, for example, to produce volumetric images, improve single image uniformity, increase FOV, and / or make transitions between adjacent views smoother. A problem associated with many optical diffusers that use material scattering or uniform surface microstructures is that such diffusers tend to diffuse light similarly in all directions. This characteristic is generally an undesirable feature in the following situations: (1) maintaining high angular resolution in one direction to produce a stereoscopic effect; and (2) increasing FOV with diffusion in another direction to make the image visible from a larger viewing window. Some holographic gratings have been developed to handle this characteristic, but many such gratings are static components that require very specialized manufacturing methods and are difficult to adjust to suit different uses. For some embodiments disclosed herein, tunable diffusers and / or tunable diffuser components can be used in 3D display structures.

[0141] Many high-quality multi-view displays classified as light field displays require a very large number of light sources in order to obtain a sufficiently good resolution in both the spatial domain and the angular domain (e.g., determined by the user). The source typically needs to have a very high dynamic range in order to compensate for the optical efficiency differences associated with the optical devices that project images in different angular directions. Many μLEDs developed specifically for display applications typically have such a dynamic range. One challenge of such μLEDs can be the requirement for extremely high density assembly of microscale components. In addition, because such components need to be individually addressable, electrical connections become very difficult to arrange on a small scale. This difficulty typically leads to high costs because the number of components is very high and the manufacture of the source modules typically requires great precision.

[0142] Figure 5 is a diagram showing an exemplary 3D light field display with image areas on both sides of the display according to some embodiments. In the absence of any light scattering medium between the 3D display and the viewer, all areas of the display project the emitter image toward both eyes of the viewer. However, in general, to produce a stereoscopic image, an emitter inside the display should not be visible to both eyes at the same time. This means that the emitted beam cluster field of view (FOV) from all components of the display covers both eyes, but the individual beams need to have a FOV at the viewing distance that is narrower than the distance between the pupils of the two eyes (about 64 mm on average). The FOV of a display segment, as well as the FOV of a single emitter, can be determined by the width of the emitter row / emitter and the magnification of the imaging optics.

[0143] To make the beam cluster FOVs overlap at a specified viewing distance, the display can be curved, for example, with a specific radius, or the projection beams can be steered toward a specific point using, for example, a flat Fresnel lens sheet. Simple multi-view displays based on emitters and microlenses can also use a technique where the emitter position is slightly offset relative to the central axis of the collimating lens. If this offset increases from the central display position toward the edge of the display, the projection beam clusters from the edge of the display can be made to overlap with the central beam cluster. If the FOVs do not overlap, some parts of the 3D image may not be formed.

[0144] Due to the finite size constraints of the device and practical limitations on the focal distance, an image area is formed in front of and / or behind the display device in which the 3D image is visible. Figure 5An exemplary viewing geometry that can be achieved with a 3D LF display structure is shown. In front of the curved display, there is a 3D image area that is limited by the farthest focus distance from the display with reasonable spatial resolution and the overall display FOV. There can also be another image area behind the display that is formed with a virtual extension of the emitted beam. When the viewer is located further away and the eye resolution is lower, larger voxels can be allowed behind the display. The maximum image distance can be selected based on the minimum acceptable resolution that can be achieved with the expanded beam virtual extension.

[0145] exist Figure 5 In the embodiment, the display surface is a curved surface with a radius equal to the specified viewing distance. The overlapping beam cluster FOV forms a viewing zone 512 around the facial area of ​​the viewer 514. The size of the viewing zone 512 can determine the amount of head movement allowed for the viewer. Both eye pupils need to be inside the zone 512 at the same time so that the viewer 514 sees a stereoscopic image. For some embodiments, the size of the viewing zone 512 can be adjusted by changing the beam cluster 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 a 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 of the front of the front image zone 506. The display viewing distance 520 is the distance from the viewer's eyes to the center of the arc of the display 502. The maximum image distance 522 is the distance from the viewer's eyes to the center of the arc of the back of the rear image zone 504.

[0146] For some embodiments, the light field display structure can perform a process including the following operations: 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. For example, the display 502 can receive data and information related to the one or more rendered images. The rendered image data can be used to generate an image in the front image area 506 and / or the back image area 504.

[0147] Fig. 6A is a diagram showing an exemplary 3D light field display with an exemplary small viewing area according to some embodiments. Figure 6B is a diagram showing an exemplary 3D light field display with an exemplary large viewing area according to some embodiments. Fig. 6A and Figure 6B Each shows an exemplary viewing geometry. Fig. 6AIn FIG. 6 , a single viewer sits in front of a display with an image area 602, and both eye pupils are covered by a small viewing area 606 implemented with a narrow beam cluster FOV 604. The minimum functional width of this area is determined by the eye pupil distance (about 64 mm on average). A smaller width also means a smaller tolerance for viewing distance variations, because both in front of and behind the optimal viewing position, the narrow FOVs start to separate from each other with smaller viewing distance variations. Figure 6B In the viewing geometry of , the beam cluster FOV 654 is quite wide for a display having an image area 652 of the same size, thereby enabling multiple viewers to be located within the viewing area 656 at different viewing distances. Figure 6B In the case shown, the position tolerance is larger.

[0148] The viewing area can be increased by increasing the FOV of each display beam cluster. This change can be done by increasing the width of the light emitter row or by changing the focal length of the beam collimation optics. Unfortunately, a smaller focal length may result in larger voxels. Therefore, the focal length can be increased to achieve better resolution. This situation usually means that there is a trade-off between the optical design parameters and the device size.

[0149] In some embodiments, to produce a good resolution 3D image, each projected view beam is highly collimated and has a narrow diameter. If the beam diameter and divergence are large, the eye retina perceives the voxel as a large spot. Voxels located behind the display surface are formed with a virtual extension of the emitted beam and can be allowed to be larger because the eye's resolution becomes lower with distance.

[0150] For some embodiments, multiple viewers may view the display, such as a multi-view display. For some embodiments, the light field (LF) display structure may include a three-dimensional (3D) display such that the LF display structure includes a diffuser with directional controllability patterned on the 3D display to allow for spatially varying diffuse directional characteristics.

[0151] Fig. 7A is a diagram illustrating an exemplary ideal case of perfect collimation without any beam divergence caused by one or more geometric factors, according to some embodiments. Figure 7B is a diagram illustrating exemplary beam divergence caused by one or more geometric factors according to some embodiments. Figure 7C is a diagram showing exemplary beam divergence caused by one or more geometric factors according to some embodiments. Fig. 7AThe achievable 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 located exactly at the focal length distance from the ideal positive lens. This is the case in Fig. 7A Unfortunately, all real light sources have some surface area from which light is emitted, making them extended sources (ES). When each point of the source is imaged individually by a lens, the total beam ends up consisting of a set of collimated sub-beams that propagate in slightly different directions after the lens. FIG. 7A to FIG. 7C As shown, the total beam divergence 714, 724 increases as the source becomes larger 712, 722. This geometric factor cannot generally be avoided by any optical means and is the primary feature that causes beam divergence for relatively large light sources.

[0152] Another non-geometric feature that causes beam divergence is diffraction. A beam is a collection of phenomena that occur when a wave (of light) encounters an obstacle or slit. Diffraction is the bending of light around the corners of an aperture into a region of geometric shadow. Diffraction effects can occur in all imaging systems and cannot be eliminated even with a perfect lens design that balances all optical aberrations. Lenses that can achieve the highest optical quality are often referred to as "diffraction limited" lenses because most of the blur that remains in the image is due to diffraction. The angular resolution that can be achieved with a diffraction limited lens can be calculated according to Eq. 1:

[0153]

[0154] Where λ is the wavelength of the light, and D is the diameter of the lens aperture. From the equation, we can see that the color of the light (wavelength) and the lens aperture size (the diameter of the light entering the viewer's pupil) are the only things that have an effect on the amount of diffraction.

[0155] Fig.7D is a diagram showing an exemplary beam divergence and a first aperture size caused by diffraction according to some embodiments. Fig. 7E is a diagram showing an exemplary beam divergence and a second aperture size due to diffraction according to some embodiments. Figure 7F is a diagram showing an exemplary beam divergence and a third aperture size due to diffraction according to some embodiments. FIG. 7D to FIG. 7F Schematic diagram showing how beam divergence 734, 744, 754 increases as lens aperture size 732, 742, 752 decreases. This effect may actually be stated as a general rule in imaging optics design: if the design is diffraction limited, the only way to increase resolution is to make the aperture larger. Diffraction is usually the dominant feature causing beam divergence at relatively small light sources.

[0156] like FIG. 7A to FIG. 7C As shown, the size of the extended source has a large impact on the beam divergence that can be achieved. The source geometry or spatial distribution is actually mapped into the angular distribution of the beam, and this characteristic is visible in the resulting "far field pattern" of the source lens system. In practice, this characteristic means that if the collimating lens is positioned at the focal distance from the source, then the source is actually imaged to a relatively large distance from the lens, and the size of the image can be determined according to 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 Eq. 2:

[0157]

[0158] Fig. 8A is a diagram illustrating an exemplary image magnification lens having a first optical power according to some embodiments. Figure 8B is a diagram illustrating an exemplary image magnification lens having a second optical power according to some embodiments. Figure 8C is a diagram illustrating an exemplary image magnification lens having a third optical power according to some embodiments. FIG. 8A to FIG. 8C Eq. 2 is shown for three different distances 806, 836, 866 between the lens and the image, resulting in images 808, 838, 868 that get larger as the distance 806, 836, 866 increases. If the distance 804, 834, 864 between the source (of fixed height 802, 832, 862) and the lens is fixed, different image distances can be achieved by varying the optical power of the lens with the lens curvature. However, as the image distance becomes larger and larger compared to the focal length of the lens, the variation in the optical power of the lens becomes smaller and smaller, approaching the situation where the lens effectively collimates the emitted light into a beam that maps the spatial distribution of the source into an angular distribution and forms an image of the source without focusing.

[0159] In flat form factor goggle-free 3D displays, the display projection lens typically has a very small focal length in order to achieve a flat structure, and the light beam from a single display optics unit is projected to a relatively large viewing distance. This means that the source can be effectively imaged at a high magnification as the beam propagates to the viewer. For example, if the source size is 50μm×50μm, the projection lens focal length is 1mm, and the viewing distance is 1m, the magnification is 1000:1, and the source geometric image is 50mm×50mm. This means that a single light emitter can only be seen if one eye is inside this 50mm diameter eyebox.

[0160] For a lens with a magnification of 1000:1, if the source has a diameter of 100 μm, the resulting image is 100 mm wide and the same pixel can be visible to both eyes simultaneously, since the average distance between the pupils of the eyes is only 64 mm. In the latter case, no stereoscopic 3D image is 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 related to each other.

[0161] Geometric and diffraction effects work together, and LF display pixel designs can balance geometric and diffraction effects to achieve a specific voxel resolution. Utilizing very small light sources is emphasized when optical system measurements get closer to the wavelength of light and diffraction effects begin to dominate performance. 9A to 9D Examples are shown of how geometric and diffraction effects work together in the case of one and two extended sources imaged to a fixed distance at fixed magnification. 9A to 9D The light source spot size is shown for different geometric magnifications and diffraction effects.

[0162] Fig. 9A is a diagram showing an exemplary first light source and lens configuration according to some embodiments. Fig. 9A In the exemplary configuration of FIG. 9 , an extended source (ES) 902 is located at a focal length 904 of 10 cm from the magnifying lens. The light beams passing through the exemplary lens aperture 906 are separated by 5 cm. These light beams have a geometric image indicated as GI 908. The light source has a diffraction image height indicated by DI 910. Fig. 9A A relatively small lens aperture size is shown, and the geometric image (GI) 908 is surrounded by blur caused by diffraction, making the diffraction image (DI) 910 much larger.

[0163] Fig. 9B is a diagram showing an exemplary second light source and lens configuration according to some embodiments. Fig. 9B In the exemplary configuration of FIG. 1 , two extended sources 922, 924 are located at a focal distance 926 of 10 cm from the magnifying lens. The light beams passing through the exemplary lens aperture 928 are separated by 5 cm. These light beams generate respective images indicated as having 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. 9BThe case where two extended sources are placed side by side and imaged using the same small aperture lens is shown. Even though the GI of the two sources is different, the two source images cannot be resolved because the diffraction images overlap. In practice, this would mean that reducing the source size may not improve the achievable voxel resolution because the resulting source image size may be the same with two separate sources as with one larger source covering the area of ​​the two separate emitters. In order to resolve the two source images into separate pixels / voxels, the aperture size of the imaging lens can be increased.

[0164] Fig. 9C is a diagram showing an exemplary third light source and lens configuration according to some embodiments. Fig. 9C In the exemplary configuration of FIG. 1 , an extended source (ES) 942 is located at a focal distance 944 of 10 cm from the magnifying lens. The light beams passing through the exemplary lens aperture 946 are separated by 10 cm. These light beams generate an image indicated as having a high GI 948. The light source has a diffraction index indicated by DI 950. Fig. 9A In comparison, the distances GI 908, 948 are the same in both figures, but Fig. 9C The diffraction image height in 950 is less than Fig. 9A The diffraction image height in is 950. Fig. 9C Shown with Fig. 9A and Fig. 9B The same focal length lens, but a larger aperture 946 is used to image the extended source 942. Diffraction is reduced, and the diffraction image can be only slightly larger than the geometric image, which remains the same size because the magnification is fixed.

[0165] Fig.9D is a diagram showing an exemplary fourth light source and lens configuration according to some embodiments. Fig.9D In the exemplary configuration of FIG. 1 , two extended sources (962, 964) are located at a focal distance 966 of 10 cm from the magnifying lens. The light beams passing through the exemplary lens aperture 968 are separated by 10 cm. These light beams generate respective images indicated as having heights GI1 (970) and GI2 (974), respectively. Each light source has a respective diffraction image height indicated by DI1 (972) and DI2 (976), respectively. Fig. 9B In comparison, the distances GI1(930,970) and GI2(934,974) are the same in both figures, but Fig.9D The diffraction image height (972,976) is less than Fig. 9B The diffraction height in (932,936). Fig.9D In , two spots can be resolved because the diffraction images do not overlap, enabling the use of two different sources and improving the spatial resolution of the voxel grid.

[0166] The following journal article discusses an emerging display technology based on the use of so-called μLEDs: Vincent W. Lee, Nancy Twu, and Ioannis Kymissis, Micro-LED Technologies and Applications, 6 / 16 Information Display, pp. 16-23 (2016). Micro-LEDs are LED chips that are typically manufactured using the same technology and the same materials as other LED chips in use today. However, μLEDs are miniaturized versions of commonly available components, and μLEDs can be manufactured as small as 1 μm to 10 μm. One of the challenges of μLEDs is how to handle very small components during the display manufacturing process. The following journal article discusses one of the densest matrices that has been manufactured to date—2 μm × 2 μm chips assembled at 3 μm pitch: Templier et al., A Novel Process for Fabricating High-Resolution and Very Small Pixel-pitch GaN LED Microdisplays, SID 2017 Digest, pp. 268-271 (2017). μLEDs have been used as backlight components in televisions, but μLEDs are expected to challenge OLEDs in the μ display market in the near future. Many μLEDs are more stable components than OLEDs and are capable of producing high light intensities, which enables μLEDs to be used in many applications such as head-mounted display systems, adaptive automotive headlights (as LED matrices), and television backlights. μLEDs can also be used in 3D displays using a very dense matrix of individually addressable light emitters that can be turned on and off very quickly.

[0167] A bare μLED chip can emit a specific color with a spectral width of about 20nm to 30nm. A white light source can be produced by coating the chip with a phosphor layer that converts the light emitted by a blue or UV LED into a wider white light emission spectrum. A full-color source can also be produced by placing separate red, green, and blue LED chips side by side. When the individual color emissions are combined by the human visual system, the combination of these three primary colors can produce the perception of a full-color pixel. A very dense matrix can allow the manufacture of self-luminous full-color pixels with a total width of less than 10μm (3μm×3μm pitch).

[0168] The light extraction efficiency from the semiconductor chip is a parameter that indicates the electro-optical efficiency of the LED structure. There are several methods that aim to enhance the extraction efficiency and enable the establishment of LED-based light sources that use electrical energy efficiently, such as in mobile devices with limited power sources. It is known that one method proposed in U.S. Patent No. 7,994,527 is based on the use of shaped plastic optical elements directly integrated on top of the LED chip. Due to the lower refractive index difference, the integrated plastic shape extracts more light from the chip material compared to the chip surrounded by air. The plastic shape also guides the light in a way that increases the light extraction from the plastic piece and makes the emission pattern more directional. It is known that another method proposed in U.S. Patent No. 7,518,149 increases the light extraction from the μLED chip. This is done by shaping the chip into a form that favors light emission angles that are more perpendicular to the front facet of the semiconductor chip and enable 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 high compared to a typical μLED, and more light is emitted into the 30° emission cone compared to a typical chip with a Lambertian distribution of the emitted light evenly distributed to the surrounding hemisphere.

[0169] A number of components and systems based on liquid crystal (LC) materials have been developed for electrical control of light propagation, and such components are available at low cost in large quantities. For some embodiments, LC-based tunable components can be used in 3D displays. Such LC components may be able to cause beam adjustment without moving mechanical components. 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 too high a cost in efficiency. The following journal article describes the use of cholesteric LC (rather than the more common nematic phase crystals), which can be used, for example, for beam steering without polarization dependence, enabling increased component transmittance of OLED or μLED-based display panels: Shang, Xiaobing et al., Fast Switching Cholesteric Liquid Crystal Optical Beam Deflector with Polarization Independence, Scientific Reports, July 26, Vol. 7 (No. 1): p. 6492 (2017) ("Shang").

[0170] It is known that U.S. Patent No. 9,664,914 describes the use of LC components as electrically switchable parallax barriers in autostereoscopic 3D displays. When the LC layer is activated, the black grating structure blocks some display pixel view directions, and different images can be displayed to the viewer's two eyes. In the absence of an activated grating, the display is used as a normal 2D display. It is known that U.S. Patent No. 9,709,851 describes the use of an LC layer to form a double convex lens structure on top of a dense pixel matrix by using an electric current to reorient some LC material molecules. The LC layer can use a complex electrode design, but the LC layer can be used to switch between 2D mode and 3D mode so that these LC lenses project pixel images in different view directions. In the latter mode, multiple views at the expense of spatial resolution can be obtained because only spatial multiplexing is used to produce multi-view images. The following journal article discusses a proposed system for scanning an electrically formed lenticular LC lens across the display surface, thereby increasing the possibility of temporal multiplexing: YP. Huang et al., Autostereoscopic 3D Display with Scanning Multi-Electrode Driven Liquid Crystal (MeD-LC) Lens, 1:1 3D Research, pp. 39–42 (2010). In this case, pixels synchronized with the scanning action can be activated several times within a single scanning period, thereby generating several additional views.

[0171] As a highly birefringent material, the LC layer has different refractive indices in two orthogonal directions. According to the following journal article: H. Wang et al., Large-aperture transparent beam steering screen based on LCMPA, 55:28 Applied Optics (2016), this property can be used with, for example, a polymer microprism for switching between two beam steering states, which has a structure including two LC layers. The first active LC layer is located between two glass sheets, for example, including electrodes. The second passive layer is formed between the glass or polymer substrate and the polymer microprism sheet. When a voltage is applied, the active LC layer rotates the linear polarization of the incident light beam by 90°, perpendicular to the propagation direction. This rotation selects which refractive index 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 microprismatic polymer material is so small that no light bending occurs. In the second state, this refractive index difference causes the light to bend to a predetermined angle at the interface. This angle is typically quite small (about 1°), but it can be increased, for example (according to the following journal article: P. McManamon et al., A Review of Phased Array Steering for Narrow-Band Electrooptical Systems, 97:6 Proceedings of the IEEE, pp. 1078-1096 (2009)) by adding a holographic grating after the LC layer or by stacking several polarization-based beam steering components, so that the angle can reach a large angle of, for example, ±15° as understood according to PCT patent application No. WO2011014743.

[0172] It is known that PCT patent application No. WO2012025786 describes a hybrid system in which a beam tuning LC element is used before a rigid polymer lenticular sheet structure, and the following journal article uses an LC element after a rigid polymer lenticular sheet structure so that additional angular view directions can be generated between the directions determined by the pixel position and the lenticular optical device: 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). In these cases, time multiplexing is used together with spatial multiplexing in a 3D multi-view display. According to the following journal article: X. Xia et al., Time-Multiplexed Multi-view Three-Dimensional Display with Projector Array and Steering Screen, 26:12 Optics Express, pp. 15528-15538 (2018), the same LC-based beam steering screen component can also be used with multiple projectors in a similar manner.

[0173] In addition to beam angle steering, it is known that LC-based components with hybrid structures (as known in U.S. Patent Nos. 7,408,601 and 9,709,829 and PCT Patent Application No. WO2016135434) can also be used to adjust beam focus without mechanical movement. According to the following journal article: G. Love et al., High-Speed ​​Switchable Lens Enables the Development of a Volumetric Stereoscopic Display, Optics Express, Vol. 17 (No. 18), pp. 15716-15725 (2009), this electronic focus adjustment can be used in head-mounted devices, where stereoscopic 3D display virtual images can be moved to different focal distances from the eyes, making the images look more natural. According to the following journal article: N. Matsuda, A. Fix, and D. Lanman, Focal Surface Displays, ACM Transactions on Graphics, Vol. 36 (No. 4), pp. 1-14 (2017), beam focus adjustment can be used for goggle-free 3D displays by adjusting the position or shape of the projected image focal surface. In many cases, such as those described in exemplary 3D / LF display patents or articles, focus adjustment directly changes the entire projected image. For example, the following journal article describes an exemplary lens system including a microlens array with adjustable focal length: L. Commander, S. Day, and D. Selviah, Variable Focal Length Microlenses, 177: 1-6 Optics Communications, pp. 157-170 (2000).

[0174] Fig.10 is a diagram illustrating an exemplary variable focal length microlens array according to some embodiments. Fig.10 The structure and function of the variable focus microlens are shown. There is an LC layer 1004 located between a glass substrate 1006 and a microlens array (MLA) 1002. Both boundary material interfaces have transparent conductive indium tin oxide (ITO) pattern coatings 1010, 1012, which act as anode and cathode for active adjustment of the LC layer. If a voltage is applied, the electric field turns the LC molecules and the material refractive index changes with the linear polarization direction. For some embodiments, the amount of index change is about 0.2 for nematic liquid crystal materials and with low voltages in the range of 0V-12V. For some embodiments, the LC material refractive index (about 1.5) is set to be close to the refractive index of the MLA material.

[0175] Fig.10 Three exemplary beams 1016 of collimated light are shown that first reach the polarizer component 1008, which transmits only linearly polarized light. The beams can be made to: focus and become converging beams 1020; diverge as diverging beams 1024; or remain as collimated beams 1022 by adjusting the LC layer refractive index with an applied voltage. If the LC refractive index is adjusted to match the MLA refractive index, the interface disappears so that the beam collimation is not affected. If the refractive index is adjusted to be lower or higher than the MLA refractive index value, the beam will refract and a real focus point 1018 or a virtual focus point 1014 will be generated in front of or behind the structure.

[0176] When a voltage is applied to the LC material, the crystals align in a specific direction determined by the electric field generated above the LC material layer. In the absence of voltage, the crystals can be in a random orientation, or in some other ordered orientation produced by preparing the material using different techniques. The voltage level affects the amount of orientation, and the voltage level can be used to tune the material optical properties. If the 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 in an otherwise uniform LC layer can be adjusted. With a suitable electrode design, it is possible to create, for example, LC microlenses by adjusting the refractive index using gradual adjustment of the electric field over some areas on the LC layer.

[0177] For some embodiments, if the viewer's eyes are tracked, the diffusion angle can be changed. For some embodiments, if the diffusion angle is changed, the light emission intensity of the μLEDs can be increased, for example, to compensate for the larger light spread and maintain the same irradiance at a certain point in the viewing window. For some embodiments, if the diffusion angle is changed, the number of light sources can be increased or decreased, for example.

[0178] Fig.10Schematic diagram of a focus-tunable microlens based on LC material. The basic idea is to locally adjust the electric field over three different microlens shapes in another boundary layer fixed around the LC material layer. In the topmost case, the LC refractive index is tuned (by orienting the liquid crystal) to be less than that of the lens material, and the collimated beam is focused to a certain point. In the middle case depicted, the LC material has the same refractive index as the microlens, so that the optical interface disappears and the light is transmitted without changing the collimation. In the bottom case shown, the LC material refractive index is tuned to a higher value than the lens material, effectively creating a negative focal length lens that diverges the incident beam. The following journal article discusses this idea in more detail: S. Day and D. Selviah, Variable Focal Length Microlenses, 177:1-6 Optics Communications, pp. 157-170 (2000).

[0179] The following journal articles describe the use of liquid crystal materials in switchable or adjustable diffraction gratings: 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). Liquid crystal materials can also be used in diffusers. The switchable grating is used to split a light beam into multiple sub-beams propagating in different directions according to the grating equation, where the main optical parameter is the grating period. This parameter can be affected by the design of the LC grating electrodes, which needs to be fine enough to induce the desired high-density changing refractive index pattern to the LC material. Tunable diffusers are used to scatter light and can usually be electrically switched between a transparent state and a semi-transparent state. These components are based on electrical tuning of LC materials that have been modified to undergo some specific changes under an applied electric field.

[0180] The following journal articles describe LC diffusers based on the polymer stabilized cholesteric texture (PSCT) approach: A. Moheghi et al., PSCT for Switchable Transparent Liquid Crystal Displays, 46:1 SID2015 Digest (2015), and J. Ma, L. Shi, and DK. Yang, Bistable Polymer Stabilized Cholesteric Texture Light Shutter, 3:2 Applied Physics Express (2010). In these components, the transparent / scattering material has been prepared in such a way that the texture includes the liquid crystal material. According to the following journal articles: R. Yamaguchi et al., Normal and Reverse Mode Light Scattering Properties in Nematic Liquid Crystal Cell Using Polymer Stabilized Effect; 28:3 J. Photopolymer Sci. and Tech., pp. 319-323 (2015), and G. Nabil Hassanein, Optical Tuning of Polymer Stabilized Liquid Crystals Refractive Index, J. Lasers, Optics & Photonics, Vol. 5 (No. 3): p. 3 (2018), another type of tunable diffuser uses polymer stabilized liquid crystals (PSLCs), which have micron-sized LC droplets embedded in an optically transparent polymer matrix with a matching refractive index. If an electric field is applied to the PSLC material, the refractive index of the aligned droplets changes, 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 this type of material-based scattering, the light diffusion effect tends to be large, but the transmittance through the component is reduced because most of the light is scattered back, and there is often no control over the angular distribution of the scattered light.

[0181] Some hybrid LC diffuser optical structures have been developed. PCT patent application No. WO2016140851 is known to describe combining a switchable LC diffuser layer with a light diffusing surface structure. The diffusing surface is a separately manufactured foil that may be laminated to a tunable component, or the diffusing surface may be an integrated structure patterned directly to the outer surface of the LC diffuser. The diffusing properties of the static diffusing surface are increased or decreased by turning the tunable diffuser on and off. U.S. Patent Application No. 2010 / 0079584 (now U.S. Patent No. 9,462,261) is known to describe a hybrid structure in which a combination of a biconvex microlens and an LC diffuser layer is used to switch an autostereoscopic display between a 2D display mode and a 3D display mode. This switching is accomplished by diffusing the angular distribution of the multi-view display by turning on the LC diffuser. PCT Patent Application No. WO2005011292 is also known to describe switching between a 2D display mode and a 3D display mode. Electrically tunable LC diffusers that can be switched between a transparent state and a semi-transparent state have been widely used, for example in volumetric displays based on sequential image projection to multiple switchable screens (as described in PCT applications No. WO02059691 and No. WO2017055894). Such components scatter light uniformly in all directions. This feature can be useful when the component is used in a volumetric display so that voxels are visible from all directions. However, such volumetric 3D images cannot produce occlusions correctly, making these images look semi-transparent and somewhat unnatural.

[0182] There are several methods for making light diffusing components. The light scattering structure can be based on, for example, internal scattering of the material, diffraction, or surface scattering. Diffraction and surface scattering methods can be used to generate surface structures that produce specific angular light distributions. For many material-based diffusion methods, the structure is more difficult to make because the light scattering particles are suspended in some medium, or the material has a fixed internal structure that diffuses the light.

[0183] It is known that U.S. Patent Application No., 2015 / 0056561 (now U.S. Patent No. 9,568,885) describes a diffuser based on surface scattering. Their light shaping diffuser (LSD) uses surface relief structures replicated from a holographically recorded master. These pseudo-random and non-periodic structures can diffuse light into some very specific angular distributions. These diffuse patterns can be designed by making microstructures with specific slope distributions that manipulate the input light and change its direction at a very small scale. Such structures can be used for accurate diffusion angle control and efficient light transmission through the component because light is not wasted due to backscattering.

[0184] For some embodiments, the optical image display structure may include a tunable light diffusion component. Some embodiments of the method may include diffusing light using a tunable light diffusion component. For some embodiments, the optical image display structure may include a 3D multi-view display device. Some embodiments of the method may include displaying a multi-view 3D image using a 3D multi-view display device. For some embodiments, the tunable light diffusion component may be a surface effect liquid crystal (SELC) diffuser. The diffuser may be an angle-selective diffusion component that can be activated without mechanical movement. The SELC diffuser scatters light from an optical interface surface that may be, for example, between a birefringent material and a substrate material having surface features of very small scale. The liquid crystal material of the SELC diffuser is used to change the polarization direction of light or the refractive index of the material, which causes the light beam to be transmitted or scattered at the designed interface surface. 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 scattering inside the material. Using optical interface surface scattering can allow for higher transmission efficiency and enable the use of components in 3D displays whose scattering properties can be selectively tuned for specific light propagation directions.

[0185] SELC diffusers can be used in many different types of 3D displays, and can improve the functionality and / or performance of other structures. In addition to 3D displays, SELC diffusers can be used, for example, to control the lighting pattern produced using LED lights. SELC diffusers can be electronically adjusted to evenly diffuse light or project light over a large area. SELC diffusers can be used, for example, for safety / privacy glazing, which can be switched between a transparent mode (to allow light to pass through the glazing) and a translucent mode (to block light from passing through the glazing). Other examples of the uses of SELC diffusers include optical measurement equipment using specific adjustable lighting patterns, photographic effects that can produce artificial bokeh effects on lens apertures, and optical connectivity modules in which tunable diffusers can be used as switches between optical channels.

[0186] For some embodiments, light is generated on a layer containing individually addressable pixels that 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 produce multiple views in the horizontal or vertical direction. A SELC diffuser located between the light emitting device and the MLA can be used to selectively diffuse the beams in two orthogonal directions to increase the image FOV and enable the display structure to be used in a mobile device that can be handheld. A polarizer located between the emitter and the diffuser can be used to linearly polarize the emitted light.

[0187] For some embodiments, the polarizer can be laminated as a foil on, for example, an MLA or on the first substrate of a SELC diffuser, making the structure more compact and robust. The cross-shaped pattern of light sources and the use of microlenses instead of lenticular sheets enable the rotation of the multi-view image orientation. Mobile devices can use this feature if the display mode is changed from portrait to landscape.

[0188] Electrically controlled diffuser components can be used to modify light direction without moving components, typically using thin optical layers. Unlike many material-based diffusers, which produce the same light distribution in both horizontal and vertical directions, for example, the use of optical interface surface scattering enables the use of components whose scattering properties can be selectively tuned for different light propagation directions.

[0189] For some embodiments, the diffuse surface topography features of the diffuser can be fabricated as a uniform structure across the entire interface surface, or can be arranged in a distinct array pattern with specific local characteristics. For examples of such diffuser patterns, see Fig.10 and Fig.11A If a uniform distribution is used over the entire surface, the electrode design can be simple and a uniform optical function can be obtained over the entire optical aperture of the diffuser.

[0190] For several different types of 3D displays, SELC diffusers can be used as tunable diffuser components, such as examples described in U.S. Patent No. 9,462,261 and PCT Patent Application Nos. WO2005011292 and WO2017055894. SELC diffusers can be used to remove the "picket fence-like" effect in 2D displays by reducing the pixel pitch, and these SELC diffusers can be used with head-mounted VR / AR / MR devices. The ability to tune the diffusion enables the fine balance between image uniformity and resolution to be adjusted. The use of SELC diffusers enables the use of multi-view 3D displays without super accurate alignment of the two optical layers, because the SELC diffuser can be used to make small alignment adjustments. For some embodiments, if the display mode changes, the active diffuser control device can perform an on / off function to activate the diffuser, which may have very low switching speed requirements. If the different color light emitters in the display are arranged with a corresponding layout, the SELC diffuser may be able to diffuse the different color emissions together at the viewing window, thereby reducing (or eliminating for some embodiments) the optical or rendering-based methods for color combination. The SELC diffuser can be used with a mobile device to switch between a portrait mode and a landscape mode. This feature can be used to reduce image processing (which may include image rendering) and associated components, such as light-emitting components. Since the number of emitter components is small, there may be fewer electrical contacts for small light-emitting μLEDs, and fewer control electronics can be used. In addition, the cross-shaped source pattern can allow more space on the source module subassembly for electrical wiring and controller components.

[0191] For some embodiments, surface effect liquid crystal (SELC) diffuser can be used as an electrically tunable optical component capable of angularly selective light diffusion. For some embodiments, light can be scattered by the optical interface surface between the birefringent material and the substrate material with very small-scale surface features. For some embodiments, liquid crystal material can be used to change the light polarization direction and / or material refractive index, which may cause the light beam to be transmitted or scattered at the interface. Using optical interface surface scattering can allow higher transmission efficiency and enable the use of components that can selectively tune scattering properties for different light propagation directions in 3D displays. Some material-based diffusers (such as polymer dispersed liquid crystal (PDLC) and polymer-stabilized cholesteric texture (PSCT)) can produce the same light distribution in both vertical and horizontal directions due to scattering inside the material.

[0192] Fig.11A is a diagram showing an exemplary two-component SELC diffuser in a beam-transmitting state according to some embodiments. Fig. 11Bis a diagram showing an exemplary two-component SELC diffuser in a beam diffusing state according to some embodiments. Fig.11A and Fig. 11B An exemplary electrically tunable optical component and its function, referred to as a surface effect liquid crystal (SELC) diffuser structure, is shown. The exemplary structure has two optical subcomponents, one active and one passive. The active subcomponent may be a thin layer of LC material 1104. A 1154 for selectively rotating the polarization of light is located between two substrates 1102, 1106 / two substrates 1152, 1156, which may be, for example, glass or polymer foil. The two substrates 1102, 1106 / two substrates 1152, 1156 may have a transparent indium tin oxide (ITO) coating 1108, 1110, 1158, 1160 and electrodes. The first subcomponent may be used as a tunable retarder for rotating the polarization direction of linearly polarized light 1120, 1170 by 90°, which may be achieved using a voltage applied to the electrodes, which generates an electric field above the LC material 1104, 1154. The polarization rotation may be activated by turning 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 these materials can be connected to each other through a common optical interface surface. The internal structural orientation and refractive index of the birefringent material can be matched with the non-birefringent material 1112, 1162 in the following way: in one incident light polarization direction, the refractive index is the same and the collimated light beam 1118 is transmitted, and in the orthogonal direction, there is a difference that causes the light to be refracted and generates a diffuse light beam with a designed divergence angle 1168. The interface surface can have a surface microstructure with a designed slope distribution. The structure can be unidirectional or bidirectional with a specific rotation orientation relative to the two optical axes of the birefringent material. For some embodiments, the second passive subcomponent can be composed of a birefringent / non-birefringent material interface, wherein the designed surface features are used to selectively transmit or diffuse light beams based on polarization. For some embodiments, the surface can be patterned into sub-regions (not shown).

[0193] Because the passive subcomponent birefringent material can have the same index of refraction as the non-birefringent material for a particular light polarization orientation, the interface between the two materials can be transparent and can transmit a beam of light with the correct linear polarization orientation without scattering. However, if the beam polarization orientation is rotated, the birefringent material index of refraction can be different, and the index difference between the two materials can be present at the interface surface. For some embodiments, surface microstructures can become visible, and light can be refracted from tiny surface features. Fig.11AIn the tunable SELC diffuser structure shown, the linearly polarized light beam is transmitted through the active component without change, and the light beam reaches the second passive component structured interface surface in a direction where there is no refractive index difference between the birefringent material and the second substrate. In this case, the light beam is transmitted. Fig. 11B The case where a voltage is applied to the active component that rotates the beam polarization direction by 90° is shown. In this second case, the rotated beam experiences a different refractive index inside the birefringent material of the passive subcomponent and a surface structured interface becomes visible, scattering the beam.

[0194] For some embodiments, the exemplary apparatus may include a diffuser configured to change the diffusion direction of the light beam when a voltage is applied to the diffuser. For some embodiments, the exemplary apparatus may also 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 apparatus may include changing the diffusion direction of the light beam when a voltage is applied to the diffuser.

[0195] For some embodiments, another exemplary device may include a liquid crystal grating configured to diffuse the light beam into two or more diffuse light beams. For some embodiments, a method of using another exemplary device may include diffusing the light beam into two or more diffuse light beams when a voltage is applied to the liquid crystal grating.

[0196] For some embodiments, a multi-view three-dimensional optical display may include a selective directional diffuser configured to be selectively activated without mechanical movement, wherein the angle-selective diffuser includes at least one surface effect liquid crystal (SELC) diffuser configured to receive and selectively directionally diffuse one or more linearly polarized and collimated light beams in response to an applied electric field.

[0197] Some embodiments of a light field (LF) display device may include a SELC diffuser including a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, such that at least one of the LC material layer, the first substrate, and the second substrate is configured to perform angularly selective diffusion of light, such as at Fig.11A and Fig. 11BFor some embodiments, the optical element may include: a first layer including an electrically adjustable liquid crystal capable of changing the polarization state of light passing through the first layer according to an electrically adjustable state; and a second layer including a birefringent material in a layer parallel to the first layer, the birefringent material including a surface structure designed to provide alternating diffusion properties to the light beam, such that 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 such that 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.

[0198] For some embodiments, the LF display device can perform a process including the following operations: emitting a light beam from one or more light emitting devices; polarizing the light beam into a linearly polarized light 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, so that the light polarization configuration state is changed to switch from a first polarization state to a second polarization state; and so that the first polarization state causes the light beam to diffuse in a first direction when passing through the birefringent material, and the second polarization state causes the light beam to diffuse in a second direction when passing through the birefringent material. For some embodiments, the SELC diffuser can include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, so that the LC material layer is configured to cause angularly selective diffusion of light in response to an applied voltage together with the first substrate and the second substrate. Examples of such operations are described in detail in detail. Fig.11A and Fig. 11B Shown in.

[0199] Fig. 12A is a diagram showing an exemplary single-component SELC diffuser in a beam-transmitting state according to some embodiments. Fig. 12B is a diagram showing an exemplary single-component SELC diffuser in a beam diffusing state according to some embodiments. Fig. 12A and Fig. 12BAn exemplary optical structure and function of a SELC diffuser 1212, 1262 is shown. In this structure, an active component is used to turn light diffusion on or off, thereby turning the linearly polarized and collimated light beams 1266, 1216 into diffused light beams 1264 or transmitted collimated light beams 1214 with a designed divergence angle, respectively. For some embodiments, a liquid crystal material layer 1204, 1254 may be located between a thin glass substrate 1202, 1252 and a second substrate 1206, 1256 having small optical surface features. The refractive index of the LC material 1204, 1254 may be adjusted to the refractive index of the second substrate material. For example, a nematic liquid crystal may have a refractive index of approximately 1.5, which is close to the refractive index of a polymethyl methacrylate (PMMA) optical polymer material of 1.49. Transparent ITO electrodes may be coated with an ITO coating 1208, 1210, 1258, 1260 on both sides of the LC material 1204, 1254, such as Fig. 12A and Fig. 12B As shown. For some embodiments, the ITO electrodes can be large because the ITO electrodes can be used to uniformly tune the refractive index of the LC material over the entire surface area. For some embodiments, the electrodes can be manufactured in 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-patterned electrodes that produce non-uniform electric fields that modify the material refractive index over a non-uniform LC material thickness. The electrodes can be patterned, for example, on top of microscopic optical shapes, or can be applied separately on the flat side of a thin substrate layer (e.g., a polymer foil) used in the manufacture of the optical shapes. The manufacture of the electrodes and optical shapes can be performed using a roll-to-roll process, which can enable coverage of large surface areas and lower costs when produced in large quantities.

[0200] exist Fig. 12B In the example SELC diffuser 1262 component structure shown, the surface microstructures between the LC material 1254 and the second substrate 1256 are unidirectional, meaning that the shapes form linear grooves in one direction. An electric field above the LC layer can be used to tune the refractive index of the LC material. If the material has the same refractive index as the second substrate, light can be transmitted. If a voltage is applied and the refractive index of the LC material is tuned to a higher value, the structured surface may become visible and light may be scattered in one direction. Thus, by applying a voltage across the LC material, a highly collimated light beam can be modified into a beam that diffuses in one direction but remains collimated in another direction, such as Fig. 12B shown.

[0201] Fig.13A is a diagram showing an exemplary SELC diffuser with a smaller divergence angle according to some embodiments. Fig. 13Bis a diagram showing an exemplary SELC diffuser with a larger divergence angle according to some embodiments. Fig.13A In , no voltage is applied to the LC material 1304 sandwiched between the first substrate 1302 and the second substrate 1306 within the diffuser, and a small divergence angle light beam 1310 is generated from the linearly polarized and collimated light beam 1308. Fig. 13B In the embodiment of the present invention, a voltage is applied to the LC material 1354 sandwiched between the first substrate 1352 and the second substrate 1356 within the diffuser, and a large divergence angle light beam 1360 is generated from the linearly polarized and collimated light beam 1358.

[0202] For some embodiments, the apparatus may include a diffuser configured to change the divergence angle of the light beam when a voltage is applied to the diffuser. For some embodiments, the method performed by the apparatus may include changing the divergence angle of the light beam when a voltage is applied to the diffuser.

[0203] Fig.14A is a diagram showing an exemplary SELC diffuser with horizontal diffusion enabled according to some embodiments. Fig. 14B is a diagram showing an exemplary SELC diffuser enabling vertical diffusion according to some embodiments. For some embodiments, a single SELC diffuser component may have more than one light diffusing surface structure. In an exemplary component structure, the liquid crystal material 1404, 1454 is located between two different material substrates 1402, 1406 / 1452, 1456, which have slightly different refractive indices, both of which can be achieved by tuning the range of the LC material refractive index. For example, if the LC material refractive index can be tuned within a range of 0.02, an optical polymer material (e.g., Zeonex 330R and Zeonex E48R) can be used as the two substrates 1402, 1406 / 1452, 1456 because the two substrates have refractive indices of 1.51 and 1.53, respectively, at a wavelength of 589nm light. With such materials, if the LC material refractive index is tuned to a value of 1.51, the first substrate interface is transparent and the second substrate interface has a refractive index difference of 0.02. The opposite is true if the LC refractive index is tuned to a value of 1.53 by applying voltage to electrodes patterned on both substrates. Such a diffuser with two different microstructures can be used as an angularly selective, tunable diffuser. If the first interface has a different slope profile than the second interface, some embodiments can, for example, make the diffuse beam divergence smaller or larger by applying voltage to the components, such as Fig.13A and Fig. 13B shown. Fig.14A and Fig. 14BTwo orthogonal linear microstructures are shown for some embodiments and are used to switch the diffusion direction of the linearly polarized and collimated light beams 1408, 1458 from horizontal diffusion 1410 of light rays 1412 to vertical diffusion 1460 of light rays 1462 by applying a voltage to the LC material.

[0204] Some embodiments of LF display structures may include two controllable diffusers such that one or more of the diffusers are configured to be selectively activated without mechanical movement. One or more of the diffusers may 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 may 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 may be configured to diffuse light in a vertical direction when the polarization state of the light is in a second polarization state. Fig.14A and Fig. 14B Shows from Fig.14A The first polarization state is switched to Fig. 14B For some embodiments, the LF display structure may include a plurality of light emitting elements, a collimating microlens capable of producing a collimated light beam, and a directionally 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.

[0205] Light scattering optical surface features can be produced, for example, in a roll-to-roll process as a polycarbonate sheet with optical shapes made of UV curable material or as a foil with an embossed structure. The surface shapes used can be flat, inclined facets (prisms) or continuously curved surfaces with different curvatures in two directions. If unidirectional surface features like, for example, biconvex microlenses are used, the components can be used to adjust the light diffusion properties in two orthogonal directions, such as Fig.11A and Fig. 11B These structures can also be manufactured by very high volume extrusion processes. Individual optical feature size and pattern fill factor can affect the beam divergence modulation that can be achieved and the amount of stray light introduced into the system that reduces image contrast. This means that high quality optical manufacturing methods can be used to produce a master that is replicated for high volume production.

[0206] One fabrication method for making diffuse surface microstructures is complex holographic diffuser replication. Light shaping diffuser (LSD) structures can have fine-tuned surface slope profiles that can modify a collimated beam to form an angular distribution such as a linear, elliptical, or rectangular illumination pattern. The beam intensity distribution can be modified to, for example, a "top hat" pattern for higher projected single beam spatial uniformity, or a Gaussian beam for higher combined beam cluster illumination uniformity.

[0207] For some embodiments, the diffuse surface shape features of the diffuser can be manufactured as a uniform structure across the entire interface surface, or can be arranged in different array patterns with specific local characteristics. If a uniform distribution is used across the entire surface, the electrode design can be simple, and uniform optical functionality can be obtained across the entire optical aperture of the diffuser. If local variations are introduced into the microstructure and / or electrode design, variations in light modulation can be made inside the optical aperture of the component. This feature can be formed, for example, by producing an interlaced matrix of tunable diffuser squares that modify the incident beam divergence in different ways in two orthogonal directions. Such a device can achieve separate control of beam portions, enabling the tuning of a single beam internal structure along with other possible optical features arranged in a mosaic pattern.

[0208] SELC diffusers are able to selectively tune the beam divergence in different angular directions. Many material-based scattering diffusers modify the beam divergence in all directions simultaneously. Electrically controlled angularly selective diffusion can be used with 3D displays that use fine control of multiple beams. Multi-view or light field displays based on panoramic imaging have spatial and angular domains so that multiple interlaced beams can be used together to produce multiple different images. In order to meet the field of view and image uniformity requirements of optical display structures, light diffusing surfaces can be used. Tunable diffuser structures can be used, for example, to improve single image uniformity, calibrate image characteristics for different viewing distances, produce volumetric images, make transitions between adjacent views smoother, rotate the display of a mobile device, or obtain image parallax in two directions.

[0209] For example, LF displays implementing SELC diffusers can be used in many different types of displays, such as HMD, volumetric 3D displays, and screen-based 3D displays. In some embodiments, certain examples of LF displays can be considered or described as holographic displays. SELC diffusers can be used in many different types of 3D displays, and can improve the functions and / or performance of other structures. In addition to 3D displays, SELC diffusers can be used, for example, to control the lighting pattern produced using LED lights. SELC diffusers can be electronically adjusted to evenly diffuse light or project light over a large area. The spotlight shape can be adjusted to a circular or elliptical shape in two different directions, and this adjustment can be made without any mechanical movement. SELC diffusers can be used for example for safety / privacy glass windows, which can be switched between a transparent mode (to allow light to pass through the glass window) and a translucent mode (to block light from passing through the glass window). Other examples of the use of SELC diffusers include optical measurement equipment using a specific adjustable lighting pattern, a photographic effect that can produce an artificial bokeh effect on a lens aperture, and an optical communication module in which a tunable diffuser can be used as a switch between optical channels.

[0210] For some embodiments, a light beam can be emitted from a light emitting device, and the horizontal diffuse propagation of the light beam can be varied by varying a horizontal light diffusion parameter (or similarly, a vertical light diffusion parameter) such as the horizontal (or vertical) size of the aperture, the full width at half maximum (FWHM) value of the light scattering distribution pattern in angular coordinates, or a voltage value used by the control electronics to achieve a specific FWHM scattering value. For some embodiments, the full width at half maximum (FWHM) value of the light scattering distribution pattern in angular coordinates can describe the optical function of the component. For some embodiments, the voltage value used by the control electronics to achieve a specific FWHM scattering value can describe the device system level control value.

[0211] For some embodiments, the horizontal light diffusion parameters may include settings for whether to apply a voltage to the LC material that is part of the diffuser, such as Fig.13A and Fig. 13B For some embodiments, the horizontal diffusion parameter may set the control voltage applied to the horizontal SELC diffuser and LC grating layer, for example, as Fig.21 As shown, or the horizontal diffusion parameter can set a target amount of diffusion to be produced by the horizontal SELC diffuser and LC grating layer in the horizontal direction. For some embodiments, the horizontal diffusion parameter can indicate the amount of voltage to be applied to the horizontal SELC diffuser and LC grating layer.

[0212] For some embodiments, a light beam may be emitted from the light emitting device, and the vertical diffuse propagation of the light beam may be varied by varying vertical light diffusion parameters such as the vertical size of the aperture. For some embodiments, the vertical light diffusion parameters may include settings for whether to apply a voltage to the LC material as part of the diffuser, such as Fig.13A and Fig. 13B For some embodiments, the vertical diffusion parameter may set the control voltage applied to the vertical SELC diffuser and LC grating layer, for example, as Fig.21 As shown, or the vertical diffusion parameter can set a target amount of diffusion to be produced by the vertical SELC diffuser and LC grating layer in the vertical direction.For some embodiments, the vertical diffusion parameter can indicate the amount of voltage to be applied to the vertical SELC diffuser and LC grating layer.

[0213] For some embodiments, the diffuser can be configured to switch between diffusing light emitted by the light emitting device in a horizontal direction and diffusing light emitted by the light emitting device in a vertical direction. For some embodiments, the diffuser can be configured to switch from diffusing light emitted by the light emitting device in a vertical direction to diffusing light emitted by the light emitting device in a horizontal direction.

[0214] For some embodiments, the exemplary device may include a diffuser configured to change the shape of the light beam when a voltage is applied to the diffuser. For some embodiments, the method performed by the exemplary device may include changing the shape of the light beam when a voltage is applied to the diffuser. For some embodiments, the exemplary device may include a diffuser configured to change the orientation of the light beam when a voltage is applied to the diffuser. For some embodiments, the method performed by the exemplary device may include changing the orientation of the light beam when a voltage is applied 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 a single coordinate plane. For some embodiments, the exemplary device may include a diffuser configured to receive a selection selected from a group consisting of a horizontal plane and a vertical plane, and diffuse light only in the selected plane. For some embodiments, the method performed by the exemplary device may include receiving a selection selected from a group consisting of a horizontal plane and a vertical plane; and diffusing light only in the selected plane.

[0215] Fig.15is a diagram showing an exemplary 3D light field optical display structure according to some embodiments. For some embodiments, the multi-view 3D display structure may include a SELC diffuser. The 3D display may use an angle-selective diffuser component (such as a SELC diffuser, for example), which may be activated without mechanical movement. Fig.15 The optical display structure and its functionality are schematically shown. 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 multiple beam FOVs 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, which are used to generate multiple views in the horizontal or vertical direction. A SELC diffuser 1508 placed in front of the MLA 1506 can be used to selectively diffuse the view beams in two orthogonal directions. Relative Fig. 12A and Fig. 12B An exemplary tunable diffuser structure is explained in more detail. A polarizer 1504 may be placed between the emitters attached to the light emitting layer 1502 and the MLA 1506 to linearly polarize the light. For some embodiments, the polarizer 1504 may be laminated as a foil, for example, on the MLA 1506 or on the first substrate of the SELC diffuser 1508, making the structure more compact and robust. For some embodiments, the light collimating structure may be a bidirectional microlens that may be fabricated, for example, as a heat embossed polymer sheet.

[0216] Fig.16A is a diagram showing an exemplary light emitter matrix layout for a full-color image with four sub-pixels per full-color light beam according to some embodiments. Fig. 16B is a diagram showing an exemplary light emitter matrix layout for a full-color image with three sub-pixels per full-color light beam according to some embodiments. Fig.16A and Fig. 16B Each shows 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 that allows different color μLEDs to be placed in horizontal and vertical arrays. These two array directions can be used to generate view beams in two orthogonal directions. For Fig.16A , a full-color pixel contains a red emitter, a green emitter, a blue emitter, and a white emitter, while for Fig. 16B, the layout contains only three different colors. White emitters can be used with, for example, high dynamic range (HDR) images by enhancing some image highlights with additional white light emission. White components can be manufactured, for example, by coating UV or blue μLED chips with a phosphor coating. Red, green, and blue can be manufactured by converting the emission of the UV or blue chip with a quantum dot (QD) coating for a specific emission spectrum. For some embodiments, pixels 1602, 1604, 1652, 1654 may include a group of one or more light-emitting devices 1606, 1608, 1610, 1656, 1658, 1660. For some embodiments, pixels 1602, 1604 including red 1606, blue 1610, green 1608, and white light-emitting devices - the light-emitting devices may be arranged in a 2×2 square arrangement, such as Fig.16A Example shown. For some embodiments, pixels including red, blue, green, and white light-emitting devices - the light-emitting devices can be arranged in a 1×4 linear arrangement. For some embodiments, for example, the horizontal resolution can be increased by changing the grouping of the light-emitting elements in the following manner: using the first group of four sub-pixels starting with the red sub-pixel, and then activating the next group of four sub-pixels starting with the white sub-pixel. This exemplary method according to some embodiments allows 3D images to have better angular resolution because the full-color pixel position offset can be performed with half-full-color pixel width intervals. For some embodiments, the light-emitting elements can be configured in a plus-sign shaped pattern, such as Fig.16A and Fig. 16B For example, one or more rows may be configured to emit light in a horizontal direction, and one or more columns may be configured to emit light in a vertical direction. Some embodiments of LF display structures may include a group of light emitting elements configured in a plus sign pattern or a cross pattern, such as Fig.16A and Fig. 16B The example shown in .

[0217] Fig.171702 is a schematic perspective view showing an exemplary 3D display in portrait mode and landscape mode according to some embodiments. An exemplary optical display structure can project several view beams from each display projector unit divided by a microlens aperture. For some embodiments, views can be generated in the horizontal direction or the vertical direction, but not in both directions at the same time. A stereoscopic effect can be generated by projecting two different images (one image to one eye) at any given point in time. For some embodiments, a first image can be projected to one eye in the horizontal view direction, and a second image can be projected to the other eye in the horizontal view direction. For some embodiments, in a 3D display application, the display may be able to generate multiple views. During the portrait mode, there may be multiple horizontal views 1702, but in order to save power, different vertical views may not be rendered, and vertical elements may not be processed. The SELC diffuser can diffuse the common view vertically. If the display is rotated, the diffusion can be switched to an orthogonal direction to generate multiple views in landscape mode 1704, or multiple views in portrait mode 1702 (depending on the applicable situation), and active / idle display elements can be exchanged. For some embodiments, other addressable applications, angular control of diffusion, can be used. Fig.17 , arrows indicate different viewing directions. To aid clarity, Fig.17 For example, in Fig.17 , light rays propagating in the vertical direction show vertical diffusion, but the view direction is at a different angle in the horizontal plane as shown.

[0218] For some embodiments, the view projection direction is the same direction as the direction determined by the viewer's two eyes, because only eye convergence is used for 3D perception. If eye convergence is used only to produce 3D image perception, retinal focus cues and super multi-view conditions can be used so that more than one view image enters a single eye pupil. In this regard, since two different views are sufficient to produce an autostereoscopic effect, the multi-view image may not be projected toward both eyes, for example. However, more than one view per eye can be used to make the eye movement range around each eye larger, thereby allowing for greater tolerance for eye movement.

[0219] A cross-shaped pattern of light sources and the use of microlenses rather than lenticular sheets enable the rotation of multi-view image orientations. This feature can be used by a mobile device if the display mode is changed from portrait to landscape. This feature can be used to reduce image processing (which can include image rendering). Fewer light sources can be used for each projector unit for some embodiments compared to a full parallax display (which can have a full matrix of emitters for each projector unit). Due to the smaller number of emitter components, there may be fewer electrical contacts for small light-emitting chips and fewer control electronics can be used. In addition, the cross-shaped source pattern can allow more space on the source module subassembly for electrical wiring and controller components.

[0220] When the light collimating optics in the display structure generate a hole collimated beam from each individual source component, the view beam can have a narrow FOV in two directions. In the absence of any diffuse components, this may mean that if the user's eye pair is not positioned exactly in the aligned vertical position relative to the display, the image may not be visible at all. For some embodiments, the view beam FOV can be increased by selectively diffusing the beam in one direction, which direction can be orthogonal to the direction in which multiple views are generated. The FOV increase can allow for tolerance in the vertical positioning of the eye, so that the device can compensate for the user's hand gripping the display device and the user's natural eye and head movement without losing the image. For many diffusers based on material scattering, the FOV cannot be increased in only one direction. Therefore, such diffusers cannot provide vertical eye position tolerance by increasing the FOV only in the vertical direction. On the contrary, however, for some embodiments, the SELC diffuser can provide unidirectional diffusion and switch between a transparent mode and a scattering mode.

[0221] For some embodiments, a LF display device such as a smart phone may include a sensor configured to detect an orientation of the display, such that the device is 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 detecting a change in the orientation of the display. Some embodiments may include a directionally controllable diffuser configured to diffuse in a vertical direction, such that if the device is in a portrait orientation, only a single vertical view is generated. For some embodiments, in response to rotation of the device, the directionally controllable diffuser may be enabled to diffuse in the rotational direction, such that if the display orientation changes from portrait to landscape, only a single view is generated in the diffuse direction.

[0222] Fig.14A and Fig. 14BThe diffuser functionality shown in can be used with a 3D multi-view display structure. For some embodiments, two separately 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 light diffusion parameters 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 been switched between a portrait mode and a landscape mode, the LF display device can select horizontal light diffusion parameters and vertical light diffusion parameters so that the light beam is diffused horizontally in the landscape mode and diffused vertically in the portrait mode, or vice versa.

[0223] Fig.18 1808 is a diagram showing an exemplary 3D display structure with a tunable LC grating according to some embodiments. Due to the limited tuning range of the LC material, the light scattering effect at the surface structure inside the SELC diffuser 1808 may be reduced. For some embodiments, if the beam divergence is not increased enough with a single SELC structure, several components can be stacked to obtain an amplification effect, which can be done under angular control. For some embodiments, the diffusion in one direction can be increased by adding an LC grating 1810 to the diffuser stack 1808. Fig.18 An example of such a multi-view 3D display structure with a single active emitter 1812, 1814 is schematically shown. Well-ordered fine grating lines induced to the LC material layer split the diffuse beam 1816 into several sub-beams 1818 that combine and produce a wider FOV beam. For some embodiments, the individual diffuse beam portions can have designed intensity distributions in order to achieve a uniform combined beam angle distribution. An example of such a distribution is a Gaussian distribution that allows multiple beams to be combined with a "top hat" type overall intensity distribution.

[0224] For some embodiments, the apparatus may include: an array of one or more groups of light emitting devices 1812, 1814 as part of a light emitting layer 1802, a polarizing layer 1804, a microlens array (MLA) 1806, one or more diffusers 1808, and one or more 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 gratings includes a liquid crystal (LC) material, such as Fig.18 An exemplary LC grating 1810 is shown in FIG.

[0225] For some embodiments, the multi-view 3D display uses spatial multiplexing so that image rendering can be performed by displaying a series of different viewpoint 2D images in different directions using view beams generated in the projector unit. The display device can be used as a multi-view 3D display with multiple views, or as a typical 2D display. The 2D display mode can be activated by displaying the same image in each direction simultaneously using the same hardware 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 remove the "picket fence-like" effect by reducing the pixel pitch. This feature can be used if the display is used in a head-mounted VR / AR / MR device. For switching image modes in mobile devices, the switching speed requirements of the SELC diffuser may be low.

[0226] For some embodiments, active synchronization between the diffuser and the light emitter is not performed because the switching can be activated using a motion sensor in the mobile device. Such a motion sensor can be used to select the correct source row orientation from the horizontal and vertical beams. Because only one of these rows is used at a given time, the source drive electronics may be less complex.

[0227] For some embodiments, neither the light emitter nor the MLA need to be accurately aligned with the SELC diffuser. Slight variations in the horizontal and vertical directions can be allowed because the diffusing surface has a continuous microstructure. However, if the microstructure is a tiled variation type, alignment can be used. Slight variations in the depth direction can be allowed because the SELC diffuser component scatters light and the function does not require an exact position. Very loose tolerances provide cost savings in the manufacturing process and can make the display robust against environmental factors such as temperature changes. This latter feature can be used with mobile devices for different environments.

[0228] Optical materials refract light with different wavelengths to different angles (color dispersion). This means that if three colored pixels (e.g., red, green, and blue) are used, different colored light beams are tilted and focused to slightly different directions and distances from the refractive features. Since the colored sub-pixels can be separated spatially, there may also be small angular differences in the colored light beam projection angles. These angular differences can be compensated in the optical structure by using a mixing layer, so that, for example, diffractive features are used for color correction. If the different color light emitters in the display are arranged with a corresponding layout, the SELC diffuser may be able to diffuse the different color emissions together at the viewing window, thereby reducing (or eliminating for some embodiments) the optical or rendering-based methods for color combination.

[0229] If the SELC diffuser is used in a continuously controlled manner instead of switching between two modes, the SELC diffuser can be used for 3D image fine-tuning. In the case where the viewer is closer to or farther away from the display and the view beam angle distribution will need to be adjusted to obtain a more uniform distribution, the SELC diffuser can be used, for example, to mix different views more smoothly. For some embodiments, a mosaic diffuser with a local tuning option can be used to diffuse adjacent view beams together, such as in the case where there is pixel-level redundancy in the 3D image content, which is a common feature of multi-view and LF images. The tracking module can also be used in the device to actively detect the viewer's eye position, and the image is only projected to those directions where the eye is located, and the FOV is expanded using the SELC diffuser. This can save some energy because the light is better concentrated and the mobile device battery life will be extended.

[0230] Several display manufacturers have developed products for switching between 2D display mode and 3D display mode in devices using basic lenticular sheets or multi-view devices based on microlenses. Some of these systems (such as, for example, it is known that there are exemplary systems described in U.S. Patent No. 9,462,261 and PCT Patent Application No. WO2005011292) use switchable LC diffusers. SELC diffusers provide angular tuning, which can be used to switch between 2D display mode and 3D display mode. It is known that U.S. Patent No. 9,250,446 describes tilted lenticular sheets. For example, the unidirectional switchable diffusion characteristics of SELC diffusers can be combined with tilted lenticular sheets to achieve better 2D image mode resolution. In the case where the surface-based diffuser component has better light transmission than the material-based scattering component, optical efficiency can be increased and energy consumption can be reduced.

[0231] One possible 3D display method using a SELC diffuser component is to use angle selectivity based on a projector-based device. For a volumetric display described in PCT patent applications No. WO2017055894 and No. WO2017055894, a series of LC diffusers are used as a switchable screen as well as an image projector. Since the SELC diffuser can be used for separate control of orthogonal diffusion directions, the switchable diffuser panel can scatter an image, and another panel diffuses another image with cross-polarization and diffusion directions. Such a device can be used to increase the total volumetric 3D image refresh rate because two sub-images can be displayed simultaneously rather than sequentially. And when the surface-based diffuser component can be designed to have better light transmission than the material-based scattering component, the optical efficiency can be increased and the energy consumption can be reduced.

[0232] For some embodiments, the device may include two or more diffusers (such as SELC diffusers), such that the first diffuser is configured to scatter light displaying a first image using a first diffuse direction, such that the second diffuser is configured to scatter light displaying a second image using a second diffuse direction, and such that the first diffuse direction is orthogonal to the second diffuse direction.

[0233] If a SELC diffuser is combined with a mosaic lens, some new functionalities and / or performance benefits can be achieved. Since the diffuser functionality is based on surface effects, different diffusion patterns can be assembled with the mosaic lens. This combination allows for better control of the projection beam partial angular range, and for example, voxels located on the display surface can be generated without fixed optical structures, allowing for higher spatial resolution on the display surface and in the virtual focal plane.

[0234] Patterned SELC diffusers can be used in augmented / mixed reality (AR / MR) headsets to improve image contrast. A diffuser surface with locally varying and tunable light scattering properties can selectively diffuse real-world image portions onto which artificial image content is projected on top of these real-world image portions. This can improve overall image quality by diffusing natural-world bright features such as specular reflections and glare that can significantly reduce image contrast. For some embodiments, at least one SELC diffuser can be configured to diffuse light to reduce glare from an image projected by an array of one or more groups of light-emitting devices.

[0235] Fig.19 is a schematic perspective view showing an exemplary mobile device viewing configuration according to some embodiments.For some embodiments, an exemplary multi-view 3D display may use a SELC diffuser component. Fig.19 A mobile device 1904 with a 6" multi-view 3D display is shown, placed at a viewing distance 1906 of 500 mm from a viewer 1902. The display is capable of projecting 13 different views 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, only one set of 13 views is generated for each multi-view 3D image in the eye-to-eye direction in order to produce a stereoscopic effect. The use of 13 views can enable the device to be rotated in one direction for different viewpoints to obtain a better 3D experience. A SELC diffuser with two orthogonal stacks of LC gratings is used to selectively expand the FOV of the narrow view beams into relatively wide viewing windows in two orthogonal directions, which allow the device to be used in a handheld manner and to adjust for natural head and eye movements.

[0236] Fig. 20is a diagram showing an exemplary μLED pattern layout according to some embodiments. Fig. 20 The layout and measurements (in μm) of an array of μLEDs used as sources in an exemplary display layout are shown. For some embodiments, the exemplary array has 23 red ("R") 2006, green ("G") 2008, and blue ("B") 2010 light source components arranged in a cross (or plus sign) pattern. The individual component dimensions 2018 are 2μm×2μm, and the pitch 2020 is 3μm. The total occupied area of ​​the source pattern is 38μm×38μm (2012, 2014). The μLEDs are bonded to a 42μm×42μm substrate (or, for some embodiments, a 50μm×50μm (2016) substrate) that contains electrical contacts for the individual sources of the source module. Extremely small light-emitting components can be bonded to subassemblies, which can be performed using manufacturing methods with higher precision than those used in assemblies of the entire display. The layout of the three different color components enables projection of 13 full-color image beams (each beam may correspond to a full-color horizontal or vertical pixel 2002, 2004) with high angular resolution in both the vertical and horizontal directions, respectively, depending on the display image mode.

[0237] Fig.21 is a diagram illustrating an exemplary display optical device structure according to some embodiments. Fig.21 The structure and measurements (in μm) of an exemplary optical display are schematically shown. For some embodiments, a 22 μm thick linear polarizer 2110 can be laminated to a polycarbonate microlens sheet 2112 that is approximately 28 μm thick and made by heat embossing. The microlenses can have apertures with rectangular 50 μm×50 μm dimensions, and the rotationally symmetric aspheric lens shape can have a radius of 35 μm and a conic constant of -0.8. The 50 μm thick 2124 polarizer-microlens sheet can be positioned 25 μm (2122) from the μLED array 2106 assembled to a common backplane 2102, which can include one or more sub-assemblies (or source modules) 2104. Such sub-assemblies can, for example, have Fig.16A , Fig. 16B or Fig. 20or another layout shown in . The backplane 2102 may include electrical contacts for the source module 2104. The opaque, heat-embossed plastic baffle aperture sheet 2108 may be used as an accurate spacer between the lens and the source, as well as for stray light suppression between the display projector unit and the microlens formed by a single source module. For example, the source module may be 38 μm (2118) wide, as shown. The source and microlens together form a multi-view display structure that is capable of projecting 13 full-color light beams from each projector unit to a total FOV (field of view) 2130 of 38° in both the vertical and horizontal directions. For some embodiments, a 6" diagonal display may include a 1500×2660 array of projector units with a 50 μm pitch size 2120, which corresponds to a 2.95"×5.24" display and 508 pixels per inch (PPI). Some current high-quality 2D displays on mobile phones have a resolution of approximately 500 PPI.

[0238] For some embodiments, a one-dimensional array of 13 full-color pixels can produce 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), which means that the beam has a width of approximately 30 mm at a viewing distance of 500 mm. Since a single projected view beam is only visible to one eye in one direction at any given time, stereoscopic 3D images can be produced using such a display structure. Because the view projected from the edge of the display overlaps with the view projected from the center of the display, there is a different small offset inside each projector unit between the source module and the microlens position above 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 edges 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 Fig.21 The extreme view beam projection directions shown are approximately 350 mm apart.

[0239] For some embodiments, two orthogonally oriented groups 2114, 2116 of SELC diffusers and LC gratings may be located between the microlens (MLA) 2112 and the user. Fig.21As shown, a laminated SELC diffuser and two orthogonally oriented groups of LC gratings can be used to selectively diffuse the projection beam in two orthogonal directions. For some embodiments, even with a 0.5 mm thick top layer of protective glass, the entire optical display structure can have a thickness of less than 1 mm, which can be considered "thin enough", for example, for mobile phone devices. Because the diffuser component has a continuous microstructure, slight changes in any three dimensions between the multi-view display structure and the diffuser layer can be allowed. For some embodiments, only the rotational positioning between different display structures is determined. For some embodiments, the rotational positioning between different display structures has a large tolerance because the positioning only affects the diffusion direction. Because the diffuser is used to expand the FOV of the image beam in one direction, the colors emitted from adjacent μLEDs can be mixed together when the beam is diffused. Therefore, special color combination methods are not used for some embodiments. The diffusion properties can be used to balance the changes between the intensity of the source component and the exact position of the light source relative to the microlens. Therefore, a uniform overall image can be generated.

[0240] For some embodiments, the SELC diffuser component can be composed of two thin Zeonex E48R polymer substrates and a liquid crystal material layer, the refractive index of which matches the substrate refractive index (about 1.53 at a wavelength of 589nm). In one light polarization direction, the tuning range of the LC material refractive index can be about 0.02. Both polymer sheets can have a transparent ITO electrode coating, and the LC material can be located between the two layers. The polymer sheet can have two different one-dimensional surface microstructures, which follow the surface shape slope distribution common to two different optical shapes. The two polymer sheets can have an aperture width of 5μm with different surface shape parameters. For some embodiments, the first corresponding optical shape can have a radius of 2.75μm, and the second optical shape can have a radius of 0.75μm and a quadratic constant of -1. If a voltage is applied to the electrodes, these surface structures diffuse the light beam in one direction and generate a refractive index difference between the LC material and the surrounding foil. If the voltage is turned off, there is no refractive index difference, and the material interface is transparent to the input light beam. A switchable LC diffraction grating having the same structure as described in Chen is laminated to the SELC diffuser to form a tunable directional diffuser component about 76 μm thick 2126, 2128. For some embodiments, the display structure can have two diffuser components stacked side by side in an orthogonal orientation to selectively diffuse the light beam in the vertical and horizontal directions.

[0241] In the case of a refractive index difference of 0.02 between the two optical interface surfaces of the LC material and the two polymer substrates, the SELC diffuser surface microstructure shape slope distribution can be able to modify the hole collimated beam into a divergent diffuse beam of about 8℉ WHM (full width at half maximum) with a near-Gaussian intensity distribution. The diffuser component grating can be able to uniformly diffract the incident beam light energy into three orders (-1, 0 and +1) (about 33% each), so that the first order (-1, +1) beam is tilted about 6° on both sides of the zeroth (0) order beam. These three near-Gaussian beam portions are combined together to form a diffuse view beam that is wider than the individual diffuse beam portions in the diffraction direction. The combination of the SELC diffuser and the LC grating can be able to modify the divergence of a hole collimated beam into a diffuse beam with a divergence of about 18℉ WHM. Using this divergence value, a single full-color beam generated by a full-color pixel inside a display projector unit can cover a viewing window of about 160mm high at the display viewing distance. A total viewing window size of 160 mm x 350 mm may be "adequate", for example, for a handheld mobile device, as this window size may be able to compensate for some hand shaking and minor eye and head movements.

[0242] For some embodiments, the device may include a back panel and one or more baffles such that an array of one or more groups of light-emitting devices is mounted to the back panel, each group of light-emitting devices corresponds to a corresponding baffle, and each baffle at least partially separates the corresponding group of light-emitting devices from the rest of the array of one or more groups of light-emitting devices. Fig.21 An example of such an arrangement is shown.

[0243] For some embodiments, the device 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. Fig.21 An example of such an arrangement is shown.

[0244] Fig.21The structure of an exemplary 3D multi-view display that can be used in, for example, a mobile phone device is schematically presented. Light is emitted from an array of μLEDs 2106 and is linearly polarized using a polarization component 2110 attached to a microlens array (MLA) 2112. MLA 2112 collimates the emitted and polarized light into a beam that reaches a stack 2114, 2116 of liquid crystal (LC)-based components. 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 another SELC diffuser is used to diffuse light only in the horizontal direction. This is also applicable to the LC grating. If a wider scattering distribution is used, the LC grating can enhance the diffusion of light in either direction, but in some embodiments, the SELC diffuser can be operated without the LC grating. The emitted image beams 2132, 2134, 2136, 2138 show a single pixel view direction of edge rays emitted from two different light sources. The exemplary emitted image light beams 2132, 2134, 2136, 2138 are shown without any diffusion.

[0245] Fig.21 The display device in can operate 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 distorts the polarization direction so that the interface between the birefringent LC material and the linear structured substrate layer becomes diffuse. The light is diffused only in the vertical direction relative to the mobile device display viewed in portrait mode. In the horizontal direction, the light is not diffused because the incident linearly polarized light reaches the interface between the LC material inside the first SELC diffuser and the substrate so that the LC material and the substrate have matching refractive indices in the horizontal direction. Therefore, the display is able to produce different images for different horizontal directions. Therefore, a 3D stereoscopic image can be produced for the viewer. This use case is Fig.17 , where, for example, 13 views are generated in portrait mode 1702.

[0246] 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 relative to the 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 layer and the linear structured substrate is now optically transparent. The display is able to produce different images for different vertical orientations. In this case, if the phone is used in portrait mode, the viewer cannot see the 3D image. However, if the phone is rotated 90 degrees to landscape mode, the different images become visible to the viewer and the 3D image is seen. This use case is Fig.17, where, for example, 13 views are generated in landscape mode 1704.

[0247] In the third mode, both SELC diffusers are "on". Light is scattered in both the vertical and horizontal directions because the LC layer distorts the polarization direction of light incident on the two diffusers, causing the internal interface to have a refractive index difference and scatter the light. In this case, the display cannot produce different images in the vertical or horizontal directions, but this mode can be used with 2D images instead of stereoscopic 3D images. For some embodiments, certain combinations 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 so that only a single viewer sees the image.

[0248] Some embodiments of LF display structures may 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 include a surface effect liquid crystal (SELC) diffuser. For some embodiments, at least one of the at least one LC grating, the first controllable diffuser, and the second controllable diffuser may include a birefringent material. For some embodiments, the grating may include a birefringent material.

[0249] In order to test the optical functionality of the structure, a set of simulations were performed using the optical simulation software OpticsStudio 17. The described optical display structure was placed 500mm from the detector surface and four different situations were simulated. In the first case, three sources positioned at the center and two horizontal extremes of the cross-shaped source pattern were used. These tests were completed to model the optical properties of the multi-view optics and to see the selective diffusion properties of the tunable diffuser component. In the last simulation case, a horizontal row with 13 sources was used. In this case, both the vertical diffuser and the horizontal diffuser were activated to show the width and height of the viewing window that can be produced in a selected direction using a single projector unit. All simulated sources had a green 550nm center wavelength and a 20nm spectral width and the sources were positioned in a single projector unit structure. The simulation results are presented in FIG. 22A to FIG. 22D In , these figures show the irradiance distribution as a 2D plot of a 500mm x 500mm detector area at a viewing distance of 500mm. The same information is in Figure 23 to Figure 25 is shown as an irradiance curve.

[0250] Fig.22A is a diagram showing an exemplary simulated irradiance distribution without a diffuser according to some embodiments. Fig.22A The first distribution image 2200 shows that when the diffuser is not activated, the three active sources appear as three separate spots inside the viewing window.

[0251] Fig. 22B is a diagram showing an exemplary simulated irradiance distribution with a SELC diffuser according to some embodiments. Fig. 22B The second 2D distribution image 2220 shows the diffusion of the light beam in the vertical direction when the vertical SELC diffuser is activated.

[0252] Fig. 22C is a diagram showing an exemplary simulated irradiance distribution with a SELC diffuser and a grating according to some embodiments. Fig. 22C The third 2D distribution image 2240 presented in FIG. 2 shows how the activated vertical LC grating further increases the diffusion in the vertical direction. Fig. 22B and Fig. 22C , thereby illustrating the angularly selective diffusion properties of the system.

[0253] Fig.22D is a diagram showing an exemplary simulated irradiance distribution with a horizontal diffuser and a vertical diffuser activated according to some embodiments. Fig.22D The second 2D distribution image 2260 shows that the angled beams are diffused together in both the horizontal and vertical directions.

[0254] Fig.23 2304 , is a graph showing an exemplary horizontal irradiance distribution for a deactivated horizontal diffuser and grating according to some embodiments. The irradiance distribution for three sources at the viewing window with a horizontal diffuser and grating is shown as a graph of normalized irradiance 2302 versus horizontal position 2304. Fig.23 In the embodiment, the diameter of these light spots is about 25 mm to 30 mm full width at half maximum (FWHM), and these light spots have a nearly Gaussian distribution curve. Fig.23 Corresponds to Fig.22A The optical display structure shown in .

[0255] Fig.242406 corresponds to a configuration without a diffuser or grating. A second outline 2408 corresponds to a configuration with a diffuser but no grating. A third outline 2410 corresponds to a configuration with both diffusion and grating. Fig.24 A comparison of three simulated irradiance curves in the vertical direction when the vertical diffuser and the grating are activated, respectively, is presented. Fig.24 Corresponds to Fig. 22B , Fig. 22C and Fig.22D The optical display structure shown in FIG. Fig.22A , Fig. 22B and Fig. 22C The vertical centerline of the distribution is obtained. These figures show that when the SELC diffuser is activated, the view beam width increases from about 25mm FWHM to about 70mm at the viewing window. This means that the allowable deviation in the positioning of the eye pupil in the vertical direction has increased by about three times. When the grating is activated together with the SELC, the width increases to about 160mm, which is more than six times the original beam width and allows for a much larger relative vertical position offset between the display and the viewer's eye. This comparison shows that a significant increase in the view beam FOV can be achieved using the presented optical structure, thereby improving ease of use.

[0256] Fig.24 The curve in shows the 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 at the viewing window, the peak irradiance value also drops relative to the increased beam width and the user may see a dimmer picture. For some embodiments, the μLEDs may be driven with higher currents to compensate and increase the total light output.

[0257] This feature can also be used, for example, in the case of a mobile phone with a front-facing camera that can locate the viewer's eye. If the viewer's eye is located to the right of the projection centerline of the display, the SELC diffuser and / or LC grating may not be activated, and the μLED can be driven with a lower current. This mode can save energy and extend the use time of battery-driven devices. For some embodiments, the use of two different beam width modification layers can enable the use of three (for example) viewer eye position regions to adjust the display power consumption accordingly.

[0258] Fig.25is a graph showing an exemplary irradiance distribution for a row of horizontal light sources with a horizontal diffuser, a vertical diffuser, and a grating according to some embodiments. The irradiance distribution for a horizontal source row at a viewing window with a vertical diffuser, a horizontal diffuser, and a grating is shown as a graph of normalized irradiance 2502 versus horizontal position 2504. Fig.25 Shown according to Fig.22D Simulated irradiance curves obtained with the 2D distribution shown in . These curves show the width and height of the viewing window that can be obtained by activating a horizontal row of 13 sources together with a horizontal diffuser and a vertical diffuser. Such a window of about 160 mm × 350 mm size can be covered by all projector units in the display matrix. When both the horizontal diffuser and the vertical diffuser are activated simultaneously, the angular resolution of the view beam is lost due to the diffusion of the beams together. This feature can be used to display images in 2D mode using the display. While 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 placed in a cross-shaped pattern, the orientation of this viewing window can be freely rotated by 90° if the display device is rotated, for example, from landscape mode to portrait mode.

[0259] For some embodiments, independent horizontal light diffusion parameters and vertical light diffusion parameters can be selected so that one or more diffusers perform horizontal diffusion and vertical diffusion at the same time. 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. For example, a first set of diffusers and a second set of diffusers can be stacked in parallel so that the light beam is diffused to perform horizontal diffusion and vertical diffusion at the same time.

[0260] For some embodiments, a smaller number of source components can be used to make a display. For some embodiments, a cross-shaped μLED pattern can contain a total of 69 active source components, which is about 59% less than a source module using a full array (13×13=169 components). Using a cross-shaped μLED pattern can enable a less complex electrical layout to be used because there are fewer μLEDs than a full array, and less substrate surface is occupied by μLEDs. Therefore, costs can be reduced.

[0261] If the view is only generated in one direction, the cross-shaped arrangement can mean that a smaller number of images are generated for each 3D multi-view image. Therefore, image processing requirements (such as rendering and display timing) can be lower. Having only one-way multi-view parallax images at any given time may be considered sufficient by users for many use cases and can enable the use of lower cost 3D systems on more devices.

[0262] For some embodiments, the optical image display structure may include a tunable light diffusion component. Some embodiments of the method may include diffusing light using a tunable light diffusion component. For some embodiments, the optical image display structure may include a 3D multi-view display device. Some embodiments of the method may include displaying a multi-view 3D image using a 3D multi-view display device. For some embodiments, a SELC diffuser may be used, for example, to control an illumination pattern generated using an LED lamp. The SELC diffuser may be electronically adjusted to diffuse light or project light uniformly over a large area. The SELC diffuser may be used, for example, for safety / privacy glass windows, which may be switched between a transparent mode (to allow light to pass through the glass window) and a translucent mode (to block light from passing through the glass window). Because the SELC diffuser has a surface effect, some SELC diffusers may be designed to have different angular scattering and spectral selectivity characteristics compared to diffusers based on material scattering, wherein many of these diffusers based on material scattering diffusers uniformly scatter light within an angular range. For some embodiments, SELC diffusers may be used as tunable diffusers for many types of 3D displays.

[0263] Many optical components of SELC diffusers can be produced using large-scale manufacturing methods (e.g., nanoimprinting), making them less expensive to produce in large quantities. Some diffusers with surface microstructures and designed slope profiles are available in large sheet form. Similar structures and manufacturing methods can be used to make tunable diffuser structures. For the precision requirements of small screen sizes, wafer-level manufacturing using UV-curable optical materials and glass wafers can be used.

[0264] 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 much of a penalty in efficiency. With recent developments ("Shang") on the use of cholesteric LCs (rather than the more common nematic phase crystals), the cholesteric LCs can be used, for example, for beam diffusion without polarization dependence, enabling increased component transmittance for OLED or μLED-based display panels.

[0265] For some embodiments, high quality goggle-free 3D displays use small light sources (such as, for example, μLEDs) to obtain 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.

[0266] For some embodiments, the SELC diffuser can be segmented so that different portions have different degrees of diffusion. This segmentation can be used to generate spatially adaptive directional density. In such a device, some spatial regions of an image can be reproduced with different views of fine angular differences, and other spatial regions can be reproduced with views of coarse angular density.

[0267] Conventional display devices that utilize such content operations can have a uniform angular view density that is equal in all spatial regions. Therefore, redundant views may be generated, and these redundant views are displayed in regions with rough angular density. Using a SELC diffuser, a single view and a high level of diffusion can be used to generate a spatial region with a rough angular density, so that the light in all viewing directions is generated by diffusion without displaying redundant narrow views. Therefore, the displayed image can be more uniform than an image consisting of several discrete narrow beams. Using a SELC diffuser, if the content shows significant changes between views so that the uniformity tolerance is masked by content changes, discrete narrow beams can be used for some embodiments. Therefore, using a spatially patterned SELC diffuser can improve display quality and reduce the bandwidth used to display redundant views.

[0268] Fig.26 2604 is a message sequence diagram illustrating an exemplary process for processing and displaying a 3D image according to some embodiments. For some embodiments, a process including a display control 2604 receiving 2608 a field of view (FOV) selection from a user input 2602 may be performed. For some embodiments, the display control 2604 may be used, for example, to activate a privacy setting so that the image is visible to a limited FOV, or to activate a power saving mode so that light is directed from the pixel only toward the user's eyes. The user may also switch the display between a 2D display mode and a 3D display mode. In a 2D display mode, for example, only some of the light-emitting components behind each pixel are used with an activated diffuser because, for some embodiments, no direction control of the pixel image is required.

[0269] The process may also include the display control 2604 selecting 2610 diffusion parameters based on the FOV selection. The process may also include the display control 2604 selecting independent horizontal light diffusion parameters and vertical light diffusion parameters based on the FOV selection. For example, if the user selects a wide angle FOV, 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 also include the display control 2604 receiving 2612 an orientation from the user. The process may also include the display control 2604 sending 2614 diffusion control information (such as horizontal light diffusion parameters and vertical light diffusion parameters) to the display hardware 2606. The process may also include the display control 2604 receiving 2618 a 3D mode setting (such as indicating a selection of a 2D mode or a 3D mode) from the user input 2602. The process may also include the display control 2604 selecting 2616 a brightness setting. The process may also include the display control 2604 rendering 2620 an image. The process may also include the display control 2604 sending 2622 brightness information (such as backlight information) to the display hardware 2606. The process may also include the display control 2604 sending 2624 the rendered image to the display hardware 2606, which may be optical hardware of the LF display device.

[0270] 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 keep the image seen by the user at a similar brightness level. If a wider FOV is selected, the brightness may be increased, while if a narrower FOV is selected, the brightness may be reduced. Such changes in brightness may be made because a wider FOV has a greater light dispersion than a narrower FOV. For some embodiments, adjusting the brightness may include adjusting the current and / or voltage level of one or more light emitting devices, such as micro light emitting diodes (μLEDs).

[0271] For some embodiments, selecting independent horizontal and vertical light diffusion parameters can be based on the 2D / 3D mode selection. For example, if the 2D mode is selected, the diffuser can be set to pass light without diffusion (or very little diffusion) in both the horizontal and vertical dimensions, such as Fig. 12A In 3D mode, for example, the diffuser may be enabled to diffuse light in the horizontal dimension and / or the vertical dimension to enable a 3D image to be displayed.

[0272] For some embodiments, the device may include a processor and may be configured to perform the process. 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.

[0273] Fig. 27 27 is a flowchart showing an exemplary process for processing and rendering 3D images according to some embodiments. For some embodiments, a process 2700 may be performed, which includes receiving 2702 a field of view (FOV) selection for a light field (LF) display device. For some embodiments, the process 2700 may also include selecting 2704 independent horizontal light diffusion parameters and vertical light diffusion parameters based on the FOV selection. For some embodiments, the process 2700 may also include rendering 2706 one or more images for the LF display device. For some embodiments, the process 2700 may also include emitting 2708 light beams from each of the one or more light emitting devices so that the one or more rendered images are displayed using the LF display device. For some embodiments, the device may include a processor and may be configured to perform the process. For some embodiments, the device may include a processor and may be configured to control one or more light emitting devices to emit light. For some embodiments, the device may be configured to control a light diffuser, such as a SELC diffuser.

[0274] Fig.28 is a flow chart illustrating an exemplary process for processing and rendering 3D images 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 also include polarizing the light beam into a linearly polarized light beam. For some embodiments, the exemplary process may also include passing the light beam through a liquid crystal (LC) material. For some embodiments, the exemplary process may also include passing the light beam through a birefringent material. For some embodiments, the exemplary process may also 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 cause the light beam to diffuse in a first direction when passing through a birefringent material, and the second polarization state may cause the light beam to diffuse in a second direction when passing through a birefringent material.

[0275] Although methods and systems according to some embodiments are discussed in the context of virtual reality (VR), some embodiments may also be applicable to mixed reality (MR) / augmented reality (AR) contexts. In addition, although the term "head mounted display (HMD)" is used herein according to some embodiments, some embodiments may be applicable to wearable devices (which may or may not be attached to the head) capable of presenting SR content (e.g., VR, AR, and / or MR for some embodiments).

[0276] 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 light diffusion parameters and the 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.

[0277] For some embodiments of the example methods, determining the horizontal light diffusion parameter and the vertical light diffusion parameter may include selecting the horizontal light diffusion parameter and the vertical light diffusion parameter.

[0278] For some embodiments of the exemplary methods, the horizontal light diffusion parameter may be independent of the vertical light diffusion parameter.

[0279] In some embodiments, the exemplary method may include receiving a FOV selection for a LF display device.

[0280] For some embodiments of the exemplary method, horizontal may be orthogonal to vertical, and horizontal and vertical may be in the xy plane relative to the LF display.

[0281] In some embodiments, an exemplary method may include: emitting a light beam from a light emitting device of a LF display device; and changing a horizontal diffusion angle of the emitted light beam based on one or more horizontal light diffusion parameters.

[0282] For some embodiments of the exemplary method, changing the horizontal diffusion angle of the emitted light beam based on one or more horizontal parameters may include: determining whether one of the horizontal parameters is within a threshold range; and if one of the horizontal parameters is within the threshold range, activating a diffuser to increase the horizontal diffusion angle of the emitted light beam.

[0283] In some embodiments, an exemplary method may include: emitting a light beam from a light emitting device of a LF display device; and varying a vertical diffuse spread of the emitted light beam based on one or more vertical light diffusion parameters.

[0284] In some embodiments, an exemplary method may include: emitting a light beam from a light emitting device of a LF display device; and adjusting a brightness of the emitted light beam based on the FOV selection.

[0285] For some embodiments of the exemplary method, selecting independent horizontal and vertical light diffusion parameters may select horizontal and vertical light diffusion parameters that activate corresponding horizontal and vertical diffusers for simultaneous horizontal and vertical diffusion.

[0286] In some embodiments, an exemplary method may include: detecting an orientation of a LF display device; and detecting an orientation of a user, wherein selecting horizontal light diffusion parameters and vertical light diffusion parameters may also be based on at least one of the orientation of the LF display device and the orientation of the user.

[0287] In some embodiments, the exemplary method may include receiving a 2D / 3D mode selection, wherein selecting the independent horizontal light diffusion parameter and the vertical light diffusion parameter is also based on the 2D / 3D mode selection.

[0288] For some implementations of the example methods, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may indicate whether to apply a voltage to a portion of the one or more diffusers.

[0289] For some implementations of the example methods, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may be indicative of an amount of voltage applied to a portion of the one or more diffusers.

[0290] For some embodiments of the example methods, one of the horizontal light diffusion parameters may indicate a target amount of diffusion to be induced in a horizontal direction.

[0291] For some embodiments of the example methods, one of the vertical light diffusion parameters may indicate a target amount of diffusion to be induced in the vertical direction.

[0292] An example 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 embodiment of the example method.

[0293] Additional exemplary methods according to some embodiments may include: determining horizontal light diffusion parameters 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 so that the LF display device displays the one or more rendered images using the horizontal light diffusion parameters and the vertical light diffusion parameters.

[0294] For some embodiments of the additional exemplary methods, determining the horizontal light diffusion parameter and the vertical light diffusion parameter may include selecting the horizontal light diffusion parameter and the vertical light diffusion parameter.

[0295] For some embodiments of the additional exemplary methods, the horizontal light diffusion parameter may be independent of the vertical light diffusion parameter.

[0296] In some embodiments, additional exemplary methods may also include receiving a FOV selection for a LF display device.

[0297] For some embodiments of the additional exemplary methods, horizontal may be orthogonal to vertical, and horizontal and vertical may be in the xy plane relative to the LF display.

[0298] In some embodiments, additional exemplary methods can include changing a horizontal diffusion angle of at least one of the emitted light beams based on a horizontal light diffusion parameter.

[0299] For some embodiments of the additional exemplary method, the horizontal diffusion angle of the emitted light beam can be changed based on one or more horizontal parameters, including: determining whether one of the horizontal parameters is within a threshold range; and if one of the horizontal parameters is within the threshold range, activating a diffuser to increase the horizontal diffusion angle of at least one of the emitted light beams.

[0300] In some embodiments, additional exemplary methods may further include varying a vertical diffuse spread of at least one of the emitted light beams based on a vertical light diffusion parameter.

[0301] In some embodiments, additional exemplary methods may also include adjusting a brightness of at least one of the emitted light beams based on the FOV selection.

[0302] For some embodiments of the additional exemplary method, determining the horizontal light diffusion parameters and the vertical light diffusion parameters may also include selecting independent horizontal light diffusion parameters and vertical light diffusion parameters, and the method may also include activating corresponding horizontal diffusers and vertical diffusers of the LF display device to simultaneously diffuse one or more of the emitted light beams using the independent horizontal light diffusion parameters and vertical light diffusion parameters to perform horizontal diffusion and vertical diffusion at the same time.

[0303] In some embodiments, additional exemplary methods may include detecting an orientation of a LF display device, wherein selecting the independent horizontal light diffusion parameters and vertical light diffusion parameters may also be based on the orientation of the LF display device.

[0304] In some embodiments, additional exemplary methods may include receiving a 2D / 3D mode selection, wherein selecting independent horizontal light diffusion parameters and vertical light diffusion parameters may also be based on the 2D / 3D mode selection.

[0305] 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 the one or more diffusers.

[0306] For some embodiments of the additional exemplary methods, one of the horizontal light diffusion parameter and the vertical light diffusion parameter may indicate an amount of voltage applied to a portion of the one or more diffusers.

[0307] For some embodiments of the additional exemplary methods, one of the horizontal light diffusion parameters may indicate a target amount of diffusion to be induced in a horizontal direction.

[0308] For some embodiments of the additional exemplary methods, one of the vertical light diffusion parameters may indicate a target amount of diffusion to be induced in the vertical direction.

[0309] 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 embodiment of the additional exemplary methods.

[0310] Additional exemplary apparatus according to some embodiments may include: an array of light emitting devices; a polarizing layer; a microlens array (MLA); one or more diffusers; and one or more gratings.

[0311] For some embodiments of additional exemplary apparatuses, the array of light emitting devices may include one or more groups of light emitting devices.

[0312] For some embodiments of additional exemplary apparatuses, each light emitting device in the one or more groups of light emitting devices may include a pixel.

[0313] In some embodiments, additional exemplary apparatus may further include: a back panel; and one or more baffles, wherein an array of one or more groups of light-emitting devices can be mounted to the back panel, wherein each group of light-emitting devices in the array can correspond to a corresponding baffle, and wherein each baffle can at least partially separate the corresponding group of light-emitting devices from the rest of the array of one or more groups of light-emitting devices.

[0314] For some embodiments of additional exemplary devices, at least one of the one or more diffusers can 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 can be configured to diffuse light emitted by at least one of the light emitting devices in a vertical direction.

[0315] For some embodiments of additional 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 emitted by at least one of the light emitting devices in a vertical direction.

[0316] For some embodiments of additional exemplary devices, at least one of the one or more diffusers may be a surface effect liquid crystal (SELC) diffuser.

[0317] For some embodiments of additional exemplary devices, the SELC diffuser may include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, the LC material layer being configured to selectively provide, in conjunction with the first substrate and the second substrate, at least one of an angular adjustment or a horizontal adjustment and / or a vertical adjustment relative to the plane of the SELC diffuser in response to an applied voltage.

[0318] For some embodiments of additional exemplary devices, the SELC diffuser may include a liquid crystal (LC) material layer sandwiched between a first substrate and a second substrate, and the LC material layer, the first substrate, and the second substrate have selected material properties that work together to achieve directional adjustment of the light beam.

[0319] For some embodiments of additional example apparatus, at least one of the diffusers may be configured to switch between a two-dimensional display mode and a three-dimensional display mode.

[0320] For some embodiments of additional exemplary devices, a first SELC diffuser among the diffusers may be a SELC diffuser configured to scatter light displaying a first image using a first diffusion direction, a second SELC diffuser among the diffusers may be a SELC diffuser configured to scatter light displaying a second image using a second diffusion direction, and the first diffusion direction may be orthogonal to the second diffusion direction.

[0321] For some embodiments of the additional example apparatus, at least one of the diffusers may be a SELC diffuser configured to diffuse light to reduce glare of an image projected by the array of light emitting devices.

[0322] For some embodiments of the additional exemplary devices, at least one of the gratings may include a liquid crystal material.

[0323] For some embodiments of the additional exemplary apparatus, at least one of the gratings may include a birefringent material.

[0324] For some embodiments of the additional example apparatus, at least one of the one or more diffusers can be configured as a mosaic diffuser to diffuse together one or more adjacent light beams emitted by one or more of the light emitting devices.

[0325] An exemplary optical element according to some embodiments may include: a first layer comprising an electrically adjustable liquid crystal capable of changing the polarization state of light passing through the first layer according to an electrically adjustable state; and a second layer comprising a birefringent material in a layer parallel to the first layer, the birefringent material comprising a surface structure designed to provide alternating diffusion properties to a light beam, wherein light incident on the second layer in a first polarization state can be scattered according to a first angular pattern, and wherein light incident on the second layer in a second polarization state can be scattered according to a second angular pattern.

[0326] An exemplary 3D display device according to some embodiments may include: an element providing directionally controllable diffusion, including: a plurality of light emitting elements and a collimating microlens capable of generating a collimated light beam; and a directionally controllable diffuser capable of switching between a first state and a second state, in which the light is diffused in a first direction and in which the light is diffused in a second direction.

[0327] In some embodiments of an exemplary 3D display device, the diffusion can be in a vertical direction and the plurality of light emitting elements are configured such that only a single vertical view is generated if no other views are rendered, if the corresponding light emitting elements are not powered, and if the display is in a portrait orientation.

[0328] In some embodiments of an exemplary 3D display device, the diffusion direction can be rotated in response to rotation of the display, and the multiple light-emitting elements are configured so that only a single view is generated if other views are not rendered, if the corresponding light-emitting elements are not powered, and if the display orientation is changed from portrait to landscape.

[0329] In some embodiments of exemplary 3D display devices, the directional controllability of the diffuser may be patterned on the display, thereby allowing spatially varying diffusion directional characteristics.

[0330] Another additional exemplary apparatus according to some embodiments may include a diffuser configured to change a diffusion direction of a light beam when a voltage is applied to the diffuser.

[0331] 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.

[0332] Another additional exemplary method according to some embodiments may include changing a diffusion direction of the light beam when applying a voltage to a diffuser.

[0333] Another additional example apparatus according to some embodiments may include a diffuser configured to change a shape of a light beam when a voltage is applied to the diffuser.

[0334] Another additional exemplary method according to some embodiments may include changing the shape of the light beam when applying a voltage to a diffuser.

[0335] Another additional exemplary apparatus according to some embodiments may include a diffuser configured to change a divergence angle of a light beam when a voltage is applied to the diffuser.

[0336] Another additional exemplary method according to some embodiments may include changing a divergence angle of a light beam when applying a voltage to a diffuser.

[0337] Another additional example apparatus according to some embodiments may include a diffuser configured to change an orientation of a light beam when a voltage is applied to the diffuser.

[0338] Another additional exemplary method according to some embodiments may include changing the orientation of the light beam when applying a voltage to the diffuser.

[0339] Another additional exemplary apparatus according to some embodiments may include a liquid crystal grating configured to diffuse a light beam into two or more diffuse light beams.

[0340] Another additional exemplary method according to some embodiments may include diffusing the light beam into two or more diffuse light beams when a voltage is applied to the liquid crystal grating.

[0341] Another additional example apparatus according to some embodiments may include a diffuser configured to diffuse light in a single coordinate plane.

[0342] Another additional exemplary method according to some embodiments may include diffusing light in a single coordinate plane.

[0343] Another additional exemplary apparatus according to some embodiments may include a diffuser configured to receive a selection selected from the group consisting of a horizontal plane and a vertical plane and diffuse light only in the selected plane.

[0344] Another additional exemplary method according to some embodiments 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.

[0345] 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, wherein the selective directional diffuser may include at least one surface effect liquid crystal (SELC) diffuser, the at least one SELC diffuser configured to receive and selectively directionally diffuse one or more linearly polarized and collimated light beams in response to an applied electric field.

[0346] An exemplary device according to some embodiments may include: a display; a first controllable diffuser covering the display, the first controllable diffuser being selectively operable to diffuse light in a first direction; and a second controllable diffuser covering the display, the second controllable diffuser being selectively operable to diffuse light in a second direction substantially perpendicular to the first direction.

[0347] For some embodiments of the example apparatus, the display may be a multi-view display.

[0348] For some embodiments of the example apparatus, at least one of the first controllable diffuser and the second controllable diffuser may include a surface effect liquid crystal (SELC) diffuser.

[0349] For some embodiments of the example 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, the first substrate, and the second substrate may be configured to perform angle-selective diffusion of light.

[0350] For some embodiments of the exemplary devices, the device may include at least one liquid crystal (LC) grating.

[0351] For some embodiments of the exemplary apparatus, at least one of the at least one LC grating, the first controllable diffuser, and the second controllable diffuser may include a birefringent material.

[0352] Some embodiments of the exemplary apparatus may further include a sensor configured to detect an orientation of the display, and the apparatus 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 detecting a change in the orientation of the display.

[0353] For some embodiments of the example apparatus, at least one of the first controllable diffuser and the second controllable diffuser may be configured to be selectively activated without mechanical movement.

[0354] For some embodiments of the example apparatus, at least one of the first controllable diffuser and the second controllable diffuser may be configured to diffuse light in response to an applied electric field.

[0355] An exemplary optical element according to some embodiments may include: a first layer, which includes an electrically adjustable liquid crystal capable of changing the polarization state of light passing through the first layer according to a state of electrical adjustment; and a second layer, which includes a birefringent material in a layer parallel to the first layer, the birefringent material including a surface structure designed to provide alternating diffusion properties to the light beam, so that 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.

[0356] 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.

[0357] Some embodiments of the exemplary device may also include: a plurality of light emitting elements and a collimating microlens capable of producing a collimated light beam; and a directionally controllable diffuser capable of switching between a first state and a second state, in which the light is diffused in a first direction and in which the light is diffused in a second direction.

[0358] For some embodiments of the exemplary optical element, the directionally controllable diffuser can be configured to diffuse in a vertical direction, and the device can be configured such that only a single vertical view is generated if the device is in a portrait orientation.

[0359] For some embodiments of the exemplary optical element, at least a portion of the plurality of light emitting elements may be arranged in a plus-sign shaped pattern.

[0360] For some embodiments of the exemplary optical element, in response to rotation of the device, the directionally controllable diffuser can be enabled to diffuse in the rotational direction, and the device can be configured so that if the display orientation changes from portrait to landscape, only a single view is generated in the diffusion direction.

[0361] Some embodiments of the exemplary apparatus may also include a three-dimensional (3D) display, such that the directional controllability of the diffuser may be patterned on the 3D display, thereby allowing for spatially varying diffuse directional characteristics.

[0362] Exemplary methods 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 light 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 a light polarization configuration state of the LC material, so that the light polarization configuration state is changed to switch from a first polarization state to a second polarization state, and so that the first polarization state causes the light beam to diffuse in a first direction when passing through the birefringent material, and the second polarization state causes the light beam to diffuse in a second direction when passing through the birefringent material.

[0363] Some embodiments of the example 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.

[0364] Some embodiments of the example method may also include receiving a field of view (FOV) selection for the LF display device.

[0365] Some embodiments of the exemplary method may also include adjusting the brightness of the emitted light beam based on the FOV selection.

[0366] An exemplary apparatus according to some embodiments may include: an array of light emitting devices; a polarizing layer; a microlens array (MLA); one or more diffusers; and one or more gratings.

[0367] For some embodiments of the example apparatus, the array of light emitting devices may include one or more groups of light emitting devices.

[0368] For some embodiments of the example apparatus, each light emitting device in the one or more groups of light emitting devices may include a pixel.

[0369] Some embodiments of the exemplary method may also include: a back panel; and one or more baffles, so that the array of one or more groups of light-emitting devices is mounted to the back panel, so that each group of light-emitting devices in the array corresponds to a corresponding baffle, and each baffle at least partially separates the corresponding group of light-emitting devices from the rest of the array of one or more groups of light-emitting devices.

[0370] 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.

[0371] For some embodiments of the example 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 emitted by at least one of the light emitting devices in a vertical direction.

[0372] For some embodiments of the example apparatus, at least one of the one or more diffusers may be a surface effect liquid crystal (SELC) diffuser.

[0373] For some embodiments of the example device, the SELC diffuser may include a liquid crystal (LC) material layer sandwiched between first and second substrates, which LC material layer may be configured to cause angle-selective diffusion of light in response to an applied voltage in conjunction with the first and second substrates.

[0374] For some embodiments of the example device, the SELC diffuser may include a liquid crystal (LC) material layer sandwiched between first and second substrates, and the LC material layer, the first and second substrates may have selected material properties that work together to scatter the light beam.

[0375] For some implementations of the example apparatus, at least one of the diffusers is configured to switch between a 2D display mode and a 3D display mode.

[0376] For some embodiments of the example device, a first SELC diffuser among the diffusers may be a SELC diffuser configured to scatter light displaying a first image using a first diffusion direction, a second SELC diffuser among the diffusers may be a SELC diffuser configured to scatter light displaying a second image using a second diffusion direction, and the first diffusion direction may be orthogonal to the second diffusion direction.

[0377] For some embodiments of the example apparatus, at least one of the diffusers may be a SELC diffuser configured to diffuse light to reduce glare of an image projected by the array of light emitting devices.

[0378] For some embodiments of the exemplary apparatus, at least one of the gratings may include a liquid crystal material.

[0379] For some embodiments of the exemplary apparatus, at least one of the gratings may include a birefringent material.

[0380] For some embodiments of the example apparatus, at least one of the one or more diffusers can be configured as a mosaic diffuser to diffuse together one or more adjacent light beams emitted by one or more of the light emitting devices.

[0381] It should be noted that the various hardware elements of one or more of the described embodiments are referred to as "modules" that perform (i.e., execute, implement, etc.) the various functions described herein in conjunction with the corresponding modules. As used herein, modules include hardware that a technician in the relevant field considers suitable for a given specific 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). Each of the modules described may also include executable instructions for performing one or more functions described as being performed by the corresponding module, and it should be noted that these instructions may take the form of or include the following instructions: hardware (i.e., hard-wired) instructions, firmware instructions, software instructions, etc., and may be stored in any suitable one or more non-transitory computer-readable media (such as commonly referred to as RAM, ROM, etc.).

[0382] Although features and elements are described above in particular combinations, it will be understood by one of ordinary skill in the art that each feature or element may be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of 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 built-in hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile disks (DVDs)). A processor associated with software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A device comprising: a display configured to project a light beam; as well as A plurality of controllable diffusers, each controllable diffuser is configured to selectively diffuse at least one of the projected light beams according to a corresponding diffusion pattern.

2. The device according to claim 1, wherein the display comprises an array of projection units, each projection unit in the array comprising: a source module configured to emit light from one or more light emitting elements; a polarization component configured to linearly polarize the emitted light; as well as a microlens configured to collimate the polarized light into a light beam, The collimated light beam originating from the light emitting element of the source module corresponds to the pixel observation direction.

3. The apparatus of claim 1 , wherein at least one of the plurality of controllable diffusers is a surface effect liquid crystal (SELC) diffuser, comprising: a liquid crystal (LC) layer having an optical interface to the substrate, Therein, the refractive index of the LC layer depends on the polarization state of light passing therethrough, which is induced by applying an electric field to the LC layer.

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

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

6. The device of claim 4, wherein the optical interface comprises a microstructure, and wherein when the SELC diffuser is operated in the first mode, light passing therethrough is scattered at a divergence angle that is distributed according to a surface slope of the microstructure.

7. The apparatus of claim 1, wherein one or more of the plurality of controllable diffusers comprises an LC grating configured to enhance diffusion of at least one of the projected light beams.

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

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

10. The apparatus according to claim 1, further comprising: a sensor configured to detect an orientation of the display, and In response to a detected change in the orientation of the display, the apparatus is 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.

11. A method comprising: projecting a light beam from a display; as well as A plurality of controllable diffusers are selectively operated to diffuse at least one of the projected light beams according to a corresponding diffusion pattern.

12. The method of claim 11, wherein the display comprises an array of projection units, and wherein projecting the light beam from the display comprises projecting the light beam from a projection unit of the array by: emitting light from the light emitting element of the source module; linearly polarizing the emitted light by the polarization component; and The polarized light is collimated into a light beam by a microlens, wherein the collimated light beam corresponds to the pixel viewing direction.

13. The method of claim 11, wherein at least one of the plurality of controllable diffusers is a SELC diffuser comprising an LC layer having an optical interface to a substrate, and wherein selectively diffusing comprises: An electric field is applied to the LC layer to induce a polarization state of light passing therethrough, wherein a refractive index of the LC layer depends on the induced polarization state.

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

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

16. The method of claim 14, wherein the optical interface comprises a microstructure, and wherein when the SELC diffuser is operated in the first mode, light passing therethrough is scattered at a divergence angle that is distributed according to a surface slope of the microstructure.

17. The method of claim 11, wherein one or more of the plurality of controllable diffusers comprises an LC grating, and further comprising: The LC grating is used to enhance diffusion of at least one of the projected light beams.

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. The method according to claim 11, further comprising: detecting an orientation of the display, and In response to a detected change in orientation of the display, switching is performed 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.

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