Patent Application
20240231162
The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, these drawings demonstrate and explain various principles of the present disclosure.
Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the present disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims.
Artificial reality devices, such as virtual reality headsets, can be used to simulate and/or reproduce a variety of virtual and remote environments. For example, stereoscopic images can be displayed on an electronic display inside a headset to simulate the illusion of depth, and head tracking sensors can be used to estimate what portion of the virtual environment is being viewed by the user. However, because existing headsets are often unable to correctly render or otherwise compensate for vergence and accommodation conflicts, such simulation can cause visual fatigue and discomfort for the users. Augmented reality and mixed reality headsets may display a virtual image overlapping with real-world images. To create a comfortable viewing experience, virtual images generated by such headsets are typically displayed at distances suitable for eye accommodations of real-world images in real time during the viewing process.
Vergence-accommodation conflict is a common problem in artificial reality systems, including virtual, augmented, and mixed reality systems. “Accommodation” is a process of adjusting the focal length of an eye lens. During accommodation, the optics of an eye are adjusted to keep an object in focus on the retina as its distance from the eye varies. “Vergence” is the simultaneous movement or rotation of both eyes in opposite directions to obtain or maintain binocular vision and is connected to accommodation of the eye. Under normal conditions, when human eyes look at a new object at a distance different from an object they had been looking at, the eyes automatically change focus (by changing their shape) to provide accommodation at the new distance or vergence distance of the new object.
In accordance with various embodiments, disclosed display devices may include gradient-index liquid crystal (GRIN LC) lenses that utilize variations in liquid crystal alignment to refract light in a manner similar to conventional lenses. A GRIN LC lens, as disclosed herein, may include an electrode array that provides variations in voltages applied to a liquid crystal layer of the lens, with the variations producing a voltage gradient(s) proceeding from a center of the lens outward. Voltages applied to the liquid crystal layer may be selectively changed so as to generate different lens powers corresponding to active display conditions and/or user eye orientation. Accordingly, GRIN LC lenses, as disclosed herein, may address the vergence-accommodation conflict by compelling a user's eyes to focus at a focal distance coinciding with a vergence location of a virtual object displayed by the display device. Moreover, since the lens diopter is not determined solely by a surface shape of a GRIN LC lens, thicknesses of the disclosed GRIN LC lenses may be significantly reduced in comparison to conventional lenses.
GRIN LC lenses having large diameters may be desirable in various devices to provide a sufficient aperture. However, as the lens diameter increases, the necessary lens thickness and required voltage drop may also increase. Additionally, the required reset time may be excessively long in such larger diameter lenses. In order to produce larger diameter lenses, Fresnel resets may be included in the lens architecture. The Fresnel resets may allow for thinner GRIN LC lenses that have sufficiently fast response times. However, transition regions between Fresnel reset sections may diffract and scatter light in undesired directions, causing unpleasant image artifacts and/or distortions that are noticeable to viewers. While dark masking layers may be used to block scattered light at the transition regions, such masking layers may be visible to viewers so as to interfere with their viewing experience.
In accordance with embodiments disclosed herein, a lens system may include a GRIN LC lens and a leakage-reduction element overlapping the GRIN LC lens. The leakage-reduction element may include a guest-host liquid crystal (GHLC) layer having dye molecules dispersed in the liquid crystal solution. The dye molecules may be oriented based on orientations of nearby liquid crystal molecules in the GHLC layer. In some examples, dye molecules in first light-blocking sections of the leakage-reduction element may be oriented to block light scattered from, for example, the transition regions between Fresnel reset regions. The first light-blocking sections may overlap the transition regions of the GRIN LC lens. In various examples, the leakage-reduction element may also include second light-blocking sections located between the first light-blocking sections. Dye molecules in the second light-blocking sections may be oriented differently than dye molecules in the first light-blocking sections such that the second light-blocking sections act as polarization filters. More particularly, dye molecules in the second light-blocking sections may be oriented in a selected direction(s) to primarily allow passage of light having a particular polarization state while blocking other polarization states of light. Orientations of liquid crystal and dye molecules in each of the first and second light-blocking sections may be directed by alignment layers abutting the GHLC layers and/or by electric fields generated by electrodes overlapping the GHLC layers.
Leakage-reduction elements, as disclosed herein, may obviate the need to use a dark masking layer to block undesirable light scattering. Thus, optical characteristics of GRIN LC lenses having Fresnel resets may be improved, resulting in reduced light scattering and increased clarity in comparison to lenses utilizing masking layers. Visible lines, such as those evident on a dark masking layer, may not be present in the disclosed lens systems, which permit light passage through each of the first and second light-blocking regions. The thickness of a leakage-reduction element, as described herein, may be comparatively thin and, in some examples, may also function as a polarization layer. Accordingly, the lens systems described herein may have minimal space requirements, making them suitable for use in a variety of display systems, including various head-mounted display systems.
Features from any of the embodiments described herein may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features, and advantages will be more fully understood upon reading the following detailed description in conjunction with the accompanying drawings and claims.
The following will provide, with reference to
“Optical series,” as used herein, may refer to relative positioning of a plurality of optical elements such that light, for each optical element of the plurality of optical elements, is transmitted by that optical element before being transmitted by another optical element of the plurality of optical elements. For embodiments described herein, optical elements may be aligned in various arrangements without regard to a specific ordering within an optical series. For example, optical element A placed before optical element B, or optical element B placed before optical element A, may both be in optical series with each other. An optical series may represent a combination of optical elements having individual optical properties that are compounded with each other when placed in series.
As used herein, a material or element that is “transparent” or “optically transparent” may, for a given thickness, have a transmissivity within the visible light spectrum of at least approximately 70%, e.g., approximately 70, 80, 90, 95, 97, 98, 99, or 99.5%, including ranges between any of the foregoing values, and less than approximately 10% bulk haze, e.g., approximately 0.5, 1, 2, 4, 6, or 8% bulk haze, including ranges between any of the foregoing values. In accordance with some embodiments, a “fully transparent” material or element may have (a) a transmissivity (i.e., optical transmittance) within the visible light spectrum of at least approximately 90%, e.g., approximately 90, 95, 97, 98, 99, or 99.5%, including ranges between any of the foregoing values, (b) less than approximately 5% bulk haze, e.g., approximately 0.1, 0.25, 0.5, 1, 2, or 4% bulk haze, including ranges between any of the foregoing values, (c) less than approximately 30% reflectivity, e.g., approximately 1, 2, 5, 10, 15, 20, or 25% reflectivity, including ranges between any of the foregoing values, and (d) at least 70% optical clarity, e.g., approximately 70, 80, 90, 95, 97, 98, 99, or 99.5% optical clarity, including ranges between any of the foregoing values. Transparent and fully transparent materials will typically exhibit very low optical absorption and minimal optical scattering. In some embodiments, “transparency” may refer to internal transparency, i.e., exclusive of Fresnel reflections.
As used herein, the terms “haze” and “clarity” may refer to an optical phenomenon associated with the transmission of light through a material, and may be attributed, for example, to the refraction of light within the material, e.g., due to secondary phases or porosity and/or the reflection of light from one or more surfaces of the material. As will be appreciated by those skilled in the art, haze may be associated with an amount of light that is subject to wide angle scattering (i.e., at an angle greater than 2.5° from normal) and a corresponding loss of transmissive contrast, whereas clarity may relate to an amount of light that is subject to narrow angle scattering (i.e., at an angle less than 2.5° from normal) and an attendant loss of optical sharpness or “see through quality.”
A material or element that is “reflective” or “optically reflective” may, for example, have a transmissivity within the visible light spectrum of less than approximately 2%, e.g., less than 2, 1, 0.5, 0.2, or 0.1%, including ranges between any of the foregoing values.
As used herein, the term “approximately” in reference to a particular numeric value or range of values may, in certain embodiments, mean and include the stated value as well as all values within 10% of the stated value. Thus, by way of example, reference to the numeric value “50” as “approximately 50” may, in certain embodiments, include values equal to 50±5, i.e., values within the range 45 to 55.
Varifocal block 232 may include one or more varifocal structures in optical series. A varifocal structure is an optical device that is configured to dynamically adjust its focus in accordance with instructions from a varifocal system. In some examples, varifocal block 232 may include a GRIN LC lens as disclosed herein (see, e.g.,
The orientations of liquid crystal molecules 344 in each region of liquid crystal layer 342 may be oriented by, for example, progressively changing a voltage applied to liquid crystal layer 342 at the respective regions. For example, a voltage applied to the peripheral region of liquid crystal layer 342 may be higher or lower than a voltage applied to the central region of liquid crystal layer 342, with voltages between the central and peripheral regions progressively increasing or decreasing proceeding from the central region to the peripheral region. While rod-shaped liquid crystal molecules are illustrated in the example shown in
Incident light 346 may pass through liquid crystal layer 342, where the light is refracted by liquid crystal molecules 344. Liquid crystal molecules 344 in different regions of liquid crystal layer 342 may be oriented at varied angles so as to refract light at correspondingly different angles within each region. For example, as shown in
In some examples, different voltage profiles may be applied to liquid crystal layer 342 to change optical characteristics of GRIN LC lens 340 as needed. For example, voltages may be selectively applied by an electrode array of GRIN LC lens 340 to reorient liquid crystal molecules 344 so as to change the location of focal point F1 and an optical power of GRIN LC lens 340. In at least one embodiment, liquid crystal molecules 344 may also be selectively oriented to produce a negative diopter in GRIN LC lens 340 so as to spread incoming light outward in a manner similar to a concave lens. In this example, the negative power may be accomplished by orienting liquid crystal molecules 344 within various regions of liquid crystal layer 342 to refract light outward to an increasingly greater extent proceeding from a central region outward toward the periphery.
As shown in
A bus line 462 may be electrically coupled to at least one of driving electrodes 458 to provide selected voltages to driving electrodes 458. For example, bus line 462 may be electrically coupled to the illustrated driving electrode 458 by a via interconnect 463 extending directly between bus line 462 and the driving electrode 458. Voltages at other driving electrodes 458 may be different than the voltage applied by bus line 462 due to, for example, reductions in voltages across the inter-electrode resistors connecting other driving electrodes to the driving electrode 458 coupled to the bus line 462. Voltages applied to each of driving electrodes 458 may be controllably varied to produce desired lensing of light passing through liquid crystal layer 442. In various examples, GRIN LC lens 440 may include multiple bus lines that are each electrically coupled to different electrodes to provide separate driving zones and/or Fresnel reset regions, as discussed in more detail below. Additionally, multiple bus lines within a particular driving zone and/or Fresnel reset may be used to apply different voltages to separate driving electrodes 458 so as to provide a voltage gradient(s) between the driving electrodes 458.
According to at least one embodiment, an insulating layer 460 may be disposed over driving electrodes 458 and bus line 462. Insulating layer 460 may also surround portions of bus line 462 not directly coupled to a driving electrode 458 such that portions of insulating layer 460 are disposed between bus line 462 and other driving electrodes 458. In some examples, portions of insulating layer 460 may also be disposed in gaps G1 defined between adjacent driving electrodes 458. Insulating layer 460 may include one or more dielectric layers, which may include a stoichiometric or non-stoichiometric oxide, fluoride, oxyfluoride, nitride, oxynitride, sulfide, SiO2, TiO2, Al2O3, Y2O3, HfO2, ZrO2, Ta2O5, Cr2O3, AlF3, MgFS2, NdF3, LaF3, YF3, CeF3, YbF3, Si3N4, ZnS, and/or ZnSe.
A floating electrode array including a plurality of floating electrodes 464 may be disposed on insulating layer 460 so that insulating layer 460 is disposed between driving electrodes 458/bus line 462 and floating electrodes 464. As shown in
A first alignment layer 466A may be formed over floating electrodes 464 and portions of insulating layer 460 exposed in gap regions between adjacent floating electrodes 464. First alignment layer 466A may contact liquid crystal layer 442 and may enable proper orientation of liquid crystal molecules within liquid crystal layer 442. First alignment layer 466A may include any material and surface texture suitable for aligning liquid crystal molecules in a desired manner. For example, first alignment layer 466A may be formed of a polyimide (PI) material that is rubbed on the surface facing liquid crystal layer 442. In at least one example, first alignment layer 466A may be formed of a PI layer having a surface that is modified by irradiation with ultraviolet (UV) light to promote curing or partial curing of the PI material. Following UV irradiation, the surface of first alignment layer 466A may be mechanically rubbed in selected directions (e.g., horizontally, circularly, etc.) to provide a substantially consistent surface structure producing predictable surface alignment of liquid crystal molecules in liquid crystal layer 442. Any other suitable material or combination of materials may be included in first alignment layer 466A, including, for example, polymers (e.g., perfluoropolyether films), metal-oxides, and/or carbon nanotubes.
GRIN LC lens 440 may also include a second alignment layer 466B facing first alignment layer 466A. In some embodiments, second alignment layer 466B may be formed in the same or similar manner as first alignment layer 466A and may include the same or similar materials (e.g., PI). Additionally or alternatively, second alignment layer 466B may include any other suitable materials formed using any suitable technique providing a surface configured to adequately align liquid crystal molecules within liquid crystal layer 442 in combination with first alignment layer 466A.
Liquid crystal layer 442 may be disposed between first and second alignment layers 466A and 466B, as illustrated in
In various embodiments, GRIN LC lens 440 may additionally include at least one common electrode 468 disposed between second alignment layer 466B and second lens substrate 456B. In one example, common electrode 468 may be formed as a unitary layer overlapping all or substantially all of liquid crystal layer 442, driving electrodes 458, and floating electrodes 464. In certain examples, GRIN LC lens 440 may include multiple common electrodes 468 that together cover or substantially cover liquid crystal layer 442. An electric field may be generated between common electrode 468 and driving electrodes 458 and/or floating electrodes 464 when selected voltages are applied to common electrode 468 and driving electrodes 458. In various examples, common electrode 468 may be held at a single selected voltage and, in combination with driving electrodes 458 and/or floating electrodes 464, may enable a range of voltage differentials to be selectively applied to regions of liquid crystal layer 442. Accordingly, driving electrodes 458 may, in combination with common electrode 468, generate variable electric fields that reorient liquid crystal molecules in liquid crystal layer 442 to produce a desired lens phase profile.
Driving electrodes 458, floating electrodes 464, common electrode 468, and bus line 462 may include one or more electrically conductive materials, such as a semiconductor (e.g., a doped semiconductor), metal, carbon nanotube, graphene, oxidized graphene, fluorinated graphene, hydrogenated graphene, other graphene derivatives, carbon black, transparent conductive oxides (TCOs, e.g., indium tin oxide (ITO), zinc oxide (ZnO), indium gallium zinc oxide (IGZO), etc.), conducting polymers (e.g., PEDOT), and/or other electrically conductive material. In some embodiments, the electrodes may include a metal such as nickel, aluminum, gold, silver, platinum, palladium, tantalum, tin, copper, indium, gallium, zinc, alloys thereof, and the like. Further example transparent conductive oxides include, without limitation, aluminum-doped zinc oxide, fluorine-doped tin oxide, indium-doped cadmium oxide, indium zinc oxide, indium zinc tin oxide, indium gallium tin oxide, indium gallium zinc oxide, indium gallium zinc tin oxide, strontium vanadate, strontium niobate, strontium molybdate, and calcium molybdate. In some examples, the electrodes and/or bus line may each include one or more layers, grids, nanowires, etc. of any suitable transparent conductive material, such as transparent conductive oxides, graphene, etc. Driving electrodes 458, floating electrodes 464, common electrode 468, and/or bus line 462 may have an optical transmissivity of at least approximately 50% (e.g., approximately 50%, approximately 60%, approximately 70%, approximately 80%, approximately 90%, approximately 95%, approximately 97%, approximately 98%, approximately 99%, or approximately 99.5%, including ranges between any of the foregoing values).
Electrode patterns for GRIN LC lenses, as disclosed herein, may be configured to produce desired lens profiles when operated. For example, modeling may be utilized to determine and/or optimize various design parameters, such as the shapes of the electrodes, the number of driving electrodes, the number of Fresnel reset regions, the types of resistors coupling adjacent electrodes, and/or the number of bus lines utilized to produce adequate lens shapes and provide a sufficient range of lens power while minimizing visual aberrations and delays in response time that might be perceptible to a wearer.
A “director,” as used herein, may refer to an axis oriented in an average direction of long molecular axes of all liquid crystal molecules in a liquid crystal bulk or selected region thereof. Individual liquid crystal molecules may be more or less aligned with this directional axis. Accordingly, liquid crystal molecules, such as rod-like liquid crystal molecules, may be generally oriented such that their moments of inertia are roughly aligned along the director.
A GRIN LC lens design may include concentric ring-shaped electrodes (see, e.g.,
In various embodiments, the slope of optical path difference (OPD) vs. voltage curve 502 of a liquid crystal material, as disclosed herein, may not remain constant but may rather become substantially steeper at regions corresponding to lower voltage values. In at least one example, the nonlinearity of OPD vs. voltage curve 502 may be addressed by segmenting curve 502 into a number of different linear sections that together may better approximate the profile of curve 502 in a manner that has little or no impact on perceptible optical characteristics of the resulting GRIN LC lens. As shown in
While seven linear sections are shown in the illustrated example, curve 502 may be segregated into any other suitable number of linear sections. The number of linear sections may determine the number of interconnections and bus lines required to drive the GRIN LC lens. In the example illustrated in
As shown in
In the example of
In at least one example, a first voltage may be applied by bus line BL1 to driving electrode 658(1) and a lower or higher voltage may be applied by bus line BL3 to driving electrode 658(3). A voltage having a value between that of bus lines BL1 and BL3 may be applied by bus line BL2 to driving electrode 658(2). In some examples, voltages of driving electrodes 658 may decrease or increase linearly or substantially linearly between pairs of bus lines (see, e.g., linear sections LS1-LS7 between pairs of bus lines B1-B8 shown in
In at least one embodiment, amounts of voltage drop or increase between adjacent driving electrodes 658 and/or between neighboring bus lines may be substantially constant. Because the radial width of driving electrodes 658 progressively decreases proceeding from the center of driving electrode array 670 outward, the voltage changes may likewise change at progressively smaller intervals proceeding radially outward. The decreasing radial intervals between driving electrodes 658 may result in progressively greater changes in liquid crystal orientation proceeding radially outward along the GRIN LC lens so that a selected lens curvature (e.g., a spherical curvature) is applied to light passing through the GRIN LC lens. For example, in one embodiment, bus line BL1 may apply approximately 4 V to the center-most driving electrode 658(1) and bus line BL3 may apply approximately 0 V to the outer-most driving electrode 658(3). In this example, bus line BL2 may apply approximately 2 V to driving electrode 658(2), which is disposed at a location between driving electrodes 658(1) and 658(3). Driving electrode 658(2) may be located such that the number of driving electrodes 658 located between driving electrodes 658(1) and 658(2) is the same or nearly the same as the number of driving electrodes 658 located between driving electrodes 658(2) and 658(3). Any other suitable number, distribution, and/or configuration of driving electrodes 658 may be utilized in various examples.
In some embodiments, voltage drops between different pairs of bus lines may have different slopes so as to produce a desired lens profile in the GRIN LC lens. Any suitable combination of voltage values may be applied to bus line BL1-BL3 to produce selected electrical field gradients in an overlapping liquid crystal layer. For example, a total voltage drop between bus lines BL2 and BL3 may be more or less steep than a total voltage drop between bus lines BL1 and BL2.
Driving electrode array 670 may be divided into a plurality of Fresnel reset sections. In the example shown in
In the embodiment of
Driving electrode array 670 may be utilized to provide GRIN LC lens 641 with a segregated Fresnel structure. The GRIN LC lens may include any appropriate type of Fresnel structure, such as a Fresnel zone plate lens including areas that have a phase difference of a half-wave to adjacent areas, a diffractive Fresnel lens having a segmented parabolic phase profile where the segments are small and can result in significant diffraction, or a refractive Fresnel lens having a segmented parabolic profile where the segments are large enough so that diffraction effects are minimized. Other structures may also be used.
In some embodiments, the driving electrode array 670 may be utilized in a refractive Fresnel GRIN LC lens having a segmented parabolic profile, where the segments are large enough that the resulting diffraction angle is smaller than the angular resolution of human eyes (i.e., diffraction effects are not observable by human eyes). Such a refractive Fresnel LC lens may be referred to as a segmented phase profile (SPP) LC lens.
For a positive thin lens, optical path difference (OPD) can be approximated with a Maclaurin series to a parabolic profile as shown in Equation (1)
where r is the lens radius (i.e., half of the lens aperture) and f is the focal length. The OPD of an LC lens is proportional to the cell thickness d and the birefringence Δn of the LC material as shown in Equation (2)
The response time t of an Electrically Controlled Birefringence (ECB) LC cell, which is the time the material requires to recover to its original state, is quadratically dependent on cell thickness d (τ ∝ r4) as shown in Equation (3)
where γ and K22 are the rotational viscosity and the splay elastic constant of the LC material, respectively. As equations (1)-(3) show, there is typically a tradeoff between the aperture size and response time. Thus, designing a GRIN LC lens with large aperture and reasonable response time has conventionally presented challenges. In the disclosed embodiments, by introducing phase resets (i.e., Fresnel resets) in the parabolic phase profile, the aperture size of the LC lens may be increased without compromising the response time.
The five Fresnel reset sections FS1-FS5 of GRIN LC lens 840 may enable the corresponding LC cell thickness of GRIN LC lens 840 to be reduced up to five times, resulting in an LC cell thickness as low as approximately 14 μm. Likewise, the response time of the illustrated GRIN LC lens may be improved by a factor of up to 25. That is, the introduction of the Fresnel resets in the GRIN LC lens phase profile may enable the optical power of GRIN LC lens 840 to be adjusted sufficiently fast to keep pace with human eye accommodation (e.g., accommodation may occur in approximately 300 ms) such that the vergence-accommodation conflict may be substantially or fully resolved. The number of Fresnel resets/segments in a particular lens may be determined based on specific configurations of the Fresnel structure and the GRIN LC lens requirements, such as the desired optical power, lens aperture, switching time, and/or image quality of the GRIN LC lens.
In some examples, each bus line 1062 may be coupled to a corresponding driving electrode 1058 within each of a plurality of Fresnel reset sections (see, e.g., Fresnel reset sections FS1 and FS2 in
Light-scattering regions 1180 of GRIN LC lens 1140 are illustrated in
Light scattered from transition regions 1181 of GRIN LC lens 1140 may cause unpleasant image distortions and/or artifacts that a user may find visually objectionable. Light-scattering regions 1180 may overlap transition regions 1181 of GRIN LC lens 1140, with scattered light exiting from GRIN LC lens 1140 at or near transition regions 1181. In some examples, light-scattering regions 1180 may include portions of Fresnel reset sections FS1-FS5 located near transition regions 1181. For example, light may be scattered away from transition regions 1181 to neighboring regions. A leakage-reduction element, as discussed below, may block at least a portion of light scattered from light-scattering regions 1180. Additionally, in some embodiments, portions of the leakage-reduction element may act as a polarizer, blocking light from portions of GRIN LC lens 1140 that is not polarized in a desired manner.
In at least one example, first light-blocking sections 1284 may be positioned to overlap light-scattering regions of a GRIN LC (e.g., light-scattering regions 1180 of GRIN LC 1140 in
Second light-blocking sections 1286 may be disposed between and/or surrounding first light-blocking sections 1284 such that first and second light-blocking sections 1284 and 1286 are concentrically arranged as shown in
In various examples, light may be scattered to a significant extent at certain regions of GRIN LC lens 1340, such as transition regions between Fresnel reset sections (see, e.g., transition regions 1181 in
In some embodiments, light passing through GRIN LC lens 1340, such as E-ray 1347e and O-ray 13470, may be incident on a portion of leakage-reduction element 1382, such as a surface of first light-blocking section 1384 or second light-blocking section 1386. E-ray 1347e and O-ray 13470 passing through first light-blocking section 1384 may be respectively directed along Poynting vectors Se and So, as shown. According to at least one example, first light-blocking section 1384 may be configured to primarily block E-rays and second light-blocking section 1386 may be configured to primarily block O-rays (e.g., O-rays not having a selected polarization state).
In some examples, leakage-reduction element 1382 may include a GHLC layer solution having liquid crystal molecules and interspersed dye molecules (see, e.g.,
According to some embodiments,
In first light-blocking section 1484 shown in
In second light-blocking section 1486 shown in
First and second alignment layers 1489A and 1489B may include any material and surface texture suitable for aligning liquid crystal molecules in a desired manner. For example, first alignment layer 1489A and/or second alignment layer 1489B may be formed of a polyimide (PI) material or other suitable material. Additionally, surfaces of first and second alignment layers 1489A and 1489B may be modified in any suitable manner to induce alignment of liquid crystal molecules 1490 and dye molecules 1492 in desired orientations. In at least one example, at least a portion of first alignment layer 1489A and/or second alignment layer 1489B may be formed of a PI layer having a surface that is modified by irradiation with ultraviolet (UV) light to promote curing or partial curing of the PI material. Following UV irradiation, surface portions of first alignment layer 1489A and/or second alignment layer 1489B may be mechanically rubbed in selected directions (e.g., horizontally, circularly, etc.) to provide a substantially consistent surface structure producing predictable surface alignment of liquid crystal molecules 1490 in GHLC layer 1488. Any other suitable material or combination of materials may be included in first and second alignment layers 1489A and 1489B, including, for example, polymers (e.g., perfluoropolyether films), metal-oxides, and/or carbon nanotubes.
In at least one embodiment, first and second alignment layers 1489A and 1489B may be processed in different manners within each of first and second light-blocking sections 1484 and 1486 of leakage-reduction element 1482 to provide different alignment characteristics within each of first and second light-blocking sections 1484 and 1486. For example, first and second alignment layers 1489A and 1489B may be rubbed in different directions within each of first and second light-blocking sections 1484 and 1486. In some examples, during production of first and second alignment layers 1489A and 1489B, the surface of first alignment layer 1489A and/or second alignment layer 1489B may be rubbed in a single direction throughout each of first and second light-blocking regions 1484 and 1486. For example, the alignment surfaces of first alignment layer 1489A and second alignment layer 1489B may each be rubbed in a first linear direction. Such linear rubbing may induce alignments of liquid crystal molecules 1490 and dye molecules 1492 in directions substantially parallel to alignment surfaces of first and second alignment layers 1489A and 1489B, as shown in
According to various embodiments, the liquid crystal and dye solution of GHLC layer 1488 may include, for example, liquid crystal molecules 1490, dye molecules 1492, and/or additives, such as polymer materials, inorganic materials, and/or twist agents. In the GHLC solution of GHLC layer 1488, liquid crystal molecules 1490 may function as host molecules and dye molecules 1492 may function as guest molecules that are oriented by the host molecules surrounding the guest molecules. Rod-shaped liquid crystal molecules 1490, such as those illustrated in the examples shown in
In a light-blocking section 1584 shown in
In some examples, liquid crystal molecules 1590 and dye molecules 1592 may be oriented with their long molecular axes extending generally or substantially perpendicular to surface portions of first alignment layer 1589A and/or second alignment layer 1589B (e.g., when a voltage differential is not applied between first and second electrode layers 1599A and 1599B, as illustrated in
Changing a voltage differential applied between first and second electrode layers 1599A and 1599B may produce changes in orientations of liquid crystal molecules 1590 and dye molecules 1592. In light-blocking section 1584 shown in
Voltages may be applied to first and second electrode layers 1599A and 1599B to orient liquid crystal molecules 1590 and dye molecules 1592 in desired directions in various regions of leakage-reduction element 1582 at selected times. In some examples, the voltages applied to first and second electrode layers 1599A and 1599B may be maintained at relatively consistent levels during use, thus maintaining specified liquid crystal and dye orientations. In some examples, at least one of first electrode layer 1599A and second electrode layer 1599B may have shape(s) corresponding to defined shapes of various light-blocking sections, which may, for example, have circular or ring shapes (see, e.g., first and second light-blocking sections 1284 and 1286 shown in
In certain embodiments, separate driving electrodes (e.g., electrodes located at or near second electrode layer 1599B) may be independently controlled by a controller such that voltages may be selectively applied to each of the driving electrodes. In at least one example, a display system having leakage-reduction element 1582 may also have an eye-tracking system to detect a gaze direction for each of a user's eyes. Such an eye-tracking system may detect a user's eye gaze direction and a controller may apply voltages only to driving electrodes at or near the user's gaze direction, thus conserving power required to operate leakage-reduction element 1582. In some examples, a driving electrode layer, such as second electrode layer 1599B, may be further divided into a pixelated grid shape having a plurality of pixel shaped driving electrodes divided and arrayed in rows and columns. Such a layout may enable further fine tuning of the display to accommodate a user's preferences and adjust to the user's gaze direction on the fly. For example, pixels in a region at or near a location determined based on a user's eye gaze direction may be activated. Additionally, pixels outside this region may not be activated until the user changes their gaze to focus on other regions of the GRIN LC lens and display. Any other suitable electrode layouts may additionally or alternatively be utilized.
At step 1620 in
As described herein, the disclosed display devices and systems may include GRIN LC lenses and overlapping leakage-reduction elements that are positioned and configured to effectively block scattered and non-polarized light rays. GHLC layers included in the leakage-reduction elements may be oriented to block scattered light, including light scattered from the transition regions between Fresnel reset regions. Certain regions of the GHLC layers may also be configured to filter out non-polarized light (e.g., light not polarized in a selected linear direction). Orientations of liquid crystal and dye molecules in regions of the GHLC layers may be directed by alignment layers abutting the GHLC layers and/or by electric fields generated by electrodes overlapping the GHLC layers.
The disclosed leakage-reduction elements may obviate the need to utilize a dark masking layer or other blocking layer to reduce undesirable light scattering and/or leakage. Thus, optical characteristics of GRIN LC lenses having Fresnel resets may be improved, resulting in reduced light scattering and increased clarity. Visible lines, such as those evident on a dark masking layer, may not be present in the disclosed lens systems, which permit light passage through each of the first and second light-blocking regions. The thickness of a leakage-reduction element, as described herein, may be comparatively thin. Accordingly, lens systems including a GRIN lens and an overlapping GHLC-based leakage-reduction layer may be significantly thinner than conventional lens systems. As such, the lens systems described herein may have minimal space requirements, making them suitable for use in a variety of display systems, including various head-mounted display systems.
Example 1: A lens system includes a lens having a driving electrode array, a common electrode, and a lens liquid crystal layer disposed between the driving electrode array and the common electrode. The lens system also includes leakage-reduction element overlapping the lens, the leakage-reduction element including a guest-host liquid crystal (GHLC) layer having dye molecules in a liquid crystal solution.
Example 2: The lens system of Example 1, where the leakage-reduction element is configured to block a portion of light waves passing through the lens.
Example 3: The lens system of Example 2, where the portion of light waves blocked by the leakage-reduction element include light waves that are scattered in directions not aligned along a specified wavefront of the lens.
Example 4: The lens system of any of Examples 1-3, where the dye molecules in the GHLC layer include dichroic dye molecules.
Example 5: The lens system of any of Examples 1-4, where orientations of the dye molecules in the GHLC layer correspond to orientations of liquid crystal molecules in the liquid crystal solution.
Example 6: The lens system of any of Examples 1-5, where the leakage-reduction element includes a pair of alignment layers, with the GHLC layer disposed between the pair of alignment layers.
Example 7: The lens system of any of Examples 1-6, where the leakage-reduction element includes at least two light-blocking sections and the dye molecules are oriented in different directions within the at least two light-blocking sections.
Example 8: The lens system of Example 7, where the at least two light-blocking sections include a first light-blocking section configured to primarily block extraordinary light rays (E-rays) from the lens and a second light-blocking section configured to primarily block ordinary light rays (O-rays) from the lens.
Example 9: The lens system of any of Examples 7 and 8, where the at least two light-blocking sections include 1) a first light-blocking section in which a first portion of the dye molecules are oriented with their long molecular axes extending generally parallel to an alignment surface of the leakage-reduction element and 2) a second light-blocking section in which a second portion of the dye molecules are oriented with their long molecular axes extending obliquely or generally perpendicular to the alignment surface of the leakage-reduction element.
Example 10: The lens system of any of Examples 7-9, where the leakage-reduction element includes an alignment layer abutting the GHLC layer and a surface of the alignment layer includes a first alignment region overlapping a first light-blocking section and a second alignment region overlapping a second light-blocking section.
Example 11: The lens system of Example 10, where the first alignment region and the second alignment region are configured to orient abutting liquid crystal molecules in different directions.
Example 12: The lens system of any of Examples 7-11, where the leakage-reduction element includes at least one GHLC electrode for orienting liquid crystal molecules within the GHLC layer and the at least two light-blocking sections include a first light-blocking section that is overlapped by the at least one GHLC electrode and a second light-blocking section that is not overlapped by the at least one GHLC electrode.
Example 13: The lens system of Example 12, where orientations of liquid crystals within the first light-blocking section vary based on a voltage applied to the at least one GHLC electrode.
Example 14: The lens system of any of Examples 1-13, where the lens includes a plurality of Fresnel reset sections concentrically arranged between a center and an outer periphery of the lens.
Example 15: The lens system of Example 14, where the leakage-reduction element includes a set of first light-blocking sections that overlap transition regions between adjacent Fresnel reset sections.
Example 16: The lens system of Example 15, where the leakage-reduction element includes a set of second light-blocking sections that are each disposed between adjacent first light-blocking sections.
Example 17: The lens system of Example 16, where the second set of light-blocking sections overlap substantial portions of the Fresnel reset sections.
Example 18: A display device includes a display screen having a plurality of light emitting elements and a lens system that receives light emitted from the display screen. The lens system includes a lens having a driving electrode array, a common electrode, and a lens liquid crystal layer disposed between the driving electrode array and the common electrode. The lens system also includes a leakage-reduction element overlapping the lens, the leakage-reduction element including a GHLC layer having dye molecules in a liquid crystal solution.
Example 19: A method includes providing a lens having a driving electrode array, a common electrode, and a lens liquid crystal layer disposed between the driving electrode array and the common electrode. The method also includes disposing a leakage-reduction element overlapping the lens, the leakage-reduction element including a guest-host liquid crystal (GHLC) layer having dye molecules in a liquid crystal solution.
Example 20: The method of Example 19, where the leakage-reduction element includes an alignment layer abutting the GHLC layer. A surface of the alignment layer includes a first alignment region and a second alignment region.
HMD 1705 may present content to a user. In some examples, HMD 1705 may be an embodiment of HMD 200 described above with reference to
Eye-tracking system 236 may track eye position and eye movement of a user of HMD 1705. A camera or other optical sensor, which may be part of eye-tracking system 236 inside HMD 1705, may capture image information of a user's eye(s), and eye-tracking system 236 may use the captured information to determine interpupillary distance, interocular distance, a three dimensional (3D) position of each eye relative to HMD 1705 (e.g., for distortion adjustment purposes), including a magnitude of torsion and rotation (i.e., roll, pitch, and yaw), and gaze directions for each eye.
In some embodiments, infrared light may be emitted within HMD 1705 and reflected from each eye. The reflected light may be received or detected by the camera and analyzed to extract eye rotation from changes in the infrared light reflected by each eye. Many methods for tracking the eyes of a user may be used by eye-tracking system 236. Accordingly, eye-tracking system 236 may track up to six degrees of freedom of each eye (i.e., 3D position, roll, pitch, and yaw), and at least a subset of the tracked quantities may be combined from two eyes of a user to estimate a gaze point (i.e., a 3D location or position in the virtual scene where the user is looking). For example, eye-tracking system 236 may integrate information from past measurements, measurements identifying a position of a user's head, and 3D information describing a scene presented by electronic display 208. Thus, information for the position and orientation of the user's eyes may be used to determine the gaze point in a virtual scene presented by HMD 1705 where the user is currently looking.
Varifocal block 232 may adjust its focal length (i.e., optical power) by adjusting a focal length of one or more varifocal structures. As noted above with reference to
Vergence processing module 1730 may determine a vergence distance of a user's gaze based on the gaze point or an estimated intersection of the gaze lines determined by eye-tracking system 236. Vergence is the simultaneous movement or rotation of both eyes in opposite directions to maintain single binocular vision, which is naturally and automatically performed by the human eye. Thus, a location where a user's eyes are verged is where the user is currently looking and is also typically the location where the user's eyes are currently focused. For example, vergence processing module 1730 may triangulate the gaze lines to estimate a distance or depth from the user associated with intersection of the gaze lines. Then the depth associated with intersection of the gaze lines may be used as an approximation for the accommodation distance, which identifies a distance from the user where the user's eyes are directed. Thus, the vergence distance may allow determination of a location where the user's eyes should be focused.
Locators 230 may be objects located in specific positions on HMD 1705 relative to one another and relative to a specific reference point on HMD 1705. A locator 230 may be a light emitting diode (LED), a corner cube reflector, a reflective marker, a type of light source that contrasts with an environment in which HMD 1705 operates, or some combination thereof.
IMU 226 may be an electronic device that generates fast calibration data based on measurement signals received from one or more of head tracking sensors 1735, which generate one or more measurement signals in response to motion of HMD 1705. Examples of head tracking sensors 1735 include accelerometers, gyroscopes, magnetometers, other sensors suitable for detecting motion, correcting error associated with IMU 226, or some combination thereof.
Based on the measurement signals from head tracking sensors 1735, IMU 226 may generate fast calibration data indicating an estimated position of HMD 1705 relative to an initial position of HMD 1705. For example, head tracking sensors 1735 may include multiple accelerometers to measure translational motion (forward/back, up/down, left/right) and multiple gyroscopes to measure rotational motion (e.g., pitch, yaw, and roll). IMU 226 may, for example, rapidly sample the measurement signals and calculate the estimated position of HMD 1705 from the sampled data. Alternatively, IMU 226 may provide the sampled measurement signals to console 1720, which determines the fast calibration data.
IMU 226 may additionally receive one or more calibration parameters from console 1720. As further discussed below, the one or more calibration parameters may be used to maintain tracking of HMD 1705. Based on a received calibration parameter, IMU 226 may adjust one or more of the IMU parameters (e.g., sample rate). In some embodiments, certain calibration parameters may cause IMU 226 to update an initial position of the reference point to correspond to a next calibrated position of the reference point. Updating the initial position of the reference point as the next calibrated position of the reference point may help to reduce accumulated error associated with determining the estimated position. The accumulated error, also referred to as drift error, may cause the estimated position of the reference point to “drift” away from the actual position of the reference point over time.
Scene rendering module 1740 may receive contents for the virtual scene from a virtual reality engine 1745 and provide display content for display on electronic display 208. Scene rendering module 1740 may include a hardware central processing unit (CPU), graphics processing unit (GPU), and/or a controller/microcontroller. Additionally, scene rendering module 1740 may adjust the content based on information from eye-tracking system 236, vergence processing module 1730, IMU 226, and head tracking sensors 1735. Scene rendering module 1740 may determine a portion of the content to be displayed on electronic display 208, based on one or more of eye-tracking system 236, tracking module 1755, head tracking sensors 1735, or IMU 226. For example, scene rendering module 1740 may determine a virtual scene, or any part of the virtual scene, to be displayed to the viewer's eyes. Scene rendering module 1740 may also dynamically adjust the displayed content based on the real-time configuration of varifocal block 232. In addition, based on the information of the determined lens center shift provided by varifocal block 232, scene rendering module 1740 may determine a shift of the virtual scene to be displayed on electronic display 208.
Imaging device 1710 may provide a monitoring function for HMD 1705 and may generate slow calibration data in accordance with calibration parameters received from console 1720. Slow calibration data may include one or more images showing observed positions of locators 230 that are detectable by imaging device 1710. Imaging device 1710 may include one or more cameras, one or more video cameras, other devices capable of capturing images including one or more locators 230, or some combination thereof. Slow calibration data may be communicated from imaging device 1710 to console 1720, and imaging device 1710 may receive one or more calibration parameters from console 1720 to adjust one or more imaging parameters (e.g., focal length, focus, frame rate, ISO, sensor temperature, shutter speed, aperture, etc.).
Input/output interface 1715 may be a device that allows a user to send action requests to console 1720. An action request may be a request to perform a particular action. For example, an action request may be used to start or end an application or to perform a particular action within the application. Input/output interface 1715 may include one or more input devices such as a keyboard, a mouse, a game controller, or any other suitable device. An action request received by input/output interface 1715 may be communicated to console 1720, which performs an action corresponding to the action request. In some embodiments, input/output interface 1715 may provide haptic feedback to the user in accordance with instructions received from console 1720. For example, haptic feedback may be provided by input/output interface 1715 when an action request is received, or console 1720 may communicate instructions to input/output interface 1715 causing input/output interface 1715 to generate haptic feedback when console 1720 performs an action.
Console 1720 may provide content to HMD 1705 for presentation to the user in accordance with information received from imaging device 1710, HMD 1705, or input/output interface 1715. In one embodiment, as shown in
Application store 1750 may store one or more applications for execution by console 1720. An application may be a group of instructions that, when executed by a processor, generate content for presentation to the user. Content generated by an application may be in response to inputs received from the user via movement of HMD 1705 and/or input/output interface 1715. Examples of applications include gaming applications, conferencing applications, video playback applications, and/or other suitable applications.
Tracking module 1755 may calibrate varifocal system 1700 using one or more calibration parameters and may adjust one or more calibration parameters to reduce error in determining position of HMD 1705. For example, tracking module 1755 may adjust the focus of imaging device 1710 to obtain a more accurate position for observed locators 230 on HMD 1705. Moreover, calibration performed by tracking module 1755 may also account for information received from IMU 226. Additionally, when tracking of HMD 1705 is lost (e.g., imaging device 1710 loses line of sight of at least a threshold number of locators 230), tracking module 1755 may re-calibrate some or all of varifocal system 1700 components.
Additionally, tracking module 1755 may track the movement of HMD 1705 using slow calibration information from imaging device 1710, and determine positions of a reference point on HMD 1705 using observed locators from the slow calibration information and a model of HMD 1705. Tracking module 1755 may also determine positions of the reference point on HMD 1705 using position information from the fast calibration information from IMU 226 on HMD 1705. Additionally, tracking module 1755 may use portions of the fast calibration information, the slow calibration information, or some combination thereof, to predict a future location of HMD 1705, which is provided to virtual reality engine 1745.
Virtual reality engine 1745 may function as a controller to execute applications within varifocal system 1700 and may receive position information, acceleration information, velocity information, predicted future positions, or some combination thereof for HMD 1705 from tracking module 1755. Based on the received information, virtual reality engine 1745 may determine content to provide to HMD 1705 for presentation to the user, such as a virtual scene, one or more virtual objects to overlay onto a real-world scene, etc. In some embodiments, virtual reality engine 1745 may maintain focal capability information of varifocal block 232. Focal capability information is information that describes what focal distances are available to varifocal block 232. Focal capability information may include, e.g., a range of focus that varifocal block 232 is able to accommodate (e.g., 0 to 4 diopters) and/or combinations of settings for each activated LC lens that map to particular focal planes. In some examples, virtual reality engine 1745 may operate a GRIN LC lens(es) of varifocal block 232 by controlling voltages applied to driving electrodes and/or common electrodes of the GRIN LC lens(es).
Virtual reality engine 1745 may provide information to varifocal block 232, such as the accommodation and/or convergence parameters including what focal distances are available to varifocal block 232. Virtual reality engine 1745 may generate instructions for varifocal block 232 that cause varifocal block 232 to adjust its focal distance to a particular location. Virtual reality engine 1745 may generate the instructions based on focal capability information and, e.g., information from vergence processing module 1730, IMU 226, and head tracking sensors 1735, and provide the instructions to varifocal block 232 to configure and/or adjust adaptive assembly 232. Virtual reality engine 1745 may use the information from vergence processing module 1730, IMU 226, and/or head tracking sensors 1735 to select a focal plane to present content to the user. Additionally, virtual reality engine 1745 may perform an action within an application executing on console 1720 in response to an action request received from input/output interface 1715 and may provide feedback to the user that the action was performed. The provided feedback may, for example, include visual and/or audible feedback via HMD 1705 and/or haptic feedback via input/output interface 1715.
Embodiments of the present disclosure may include or be implemented in conjunction with various types of artificial-reality systems. Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, for example, a virtual reality, an augmented reality, a mixed reality, a hybrid reality, or some combination and/or derivative thereof. Artificial-reality content may include completely computer-generated content or computer-generated content combined with captured (e.g., real-world) content. The artificial-reality content may include video, audio, haptic feedback, or some combination thereof, any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional (3D) effect to the viewer). Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, for example, create content in an artificial reality and/or are otherwise used in (e.g., to perform activities in) an artificial reality.
Artificial-reality systems may be implemented in a variety of different form factors and configurations. Some artificial-reality systems may be designed to work without near-eye displays (NEDs). Other artificial-reality systems may include an NED that also provides visibility into the real world (such as, e.g., augmented-reality system 1800 in
Turning to
In some embodiments, augmented-reality system 1800 may include one or more sensors, such as sensor 1840. Sensor 1840 may generate measurement signals in response to motion of augmented-reality system 1800 and may be located on substantially any portion of frame 1810. Sensor 1840 may represent one or more of a variety of different sensing mechanisms, such as a position sensor, an inertial measurement unit (IMU), a depth camera assembly, a structured light emitter and/or detector, or any combination thereof. In some embodiments, augmented-reality system 1800 may or may not include sensor 1840 or may include more than one sensor. In embodiments in which sensor 1840 includes an IMU, the IMU may generate calibration data based on measurement signals from sensor 1840. Examples of sensor 1840 may include, without limitation, accelerometers, gyroscopes, magnetometers, other suitable types of sensors that detect motion, sensors used for error correction of the IMU, or some combination thereof.
In some examples, augmented-reality system 1800 may also include a microphone array with a plurality of acoustic transducers 1820(A)-1820(J), referred to collectively as acoustic transducers 1820. Acoustic transducers 1820 may represent transducers that detect air pressure variations induced by sound waves. Each acoustic transducer 1820 may be configured to detect sound and convert the detected sound into an electronic format (e.g., an analog or digital format). The microphone array in
In some embodiments, one or more of acoustic transducers 1820(A)-(J) may be used as output transducers (e.g., speakers). For example, acoustic transducers 1820(A) and/or 1820(B) may be earbuds or any other suitable type of headphone or speaker.
The configuration of acoustic transducers 1820 of the microphone array may vary. While augmented-reality system 1800 is shown in
Acoustic transducers 1820(A) and 1820(B) may be positioned on different parts of the user's ear, such as behind the pinna, behind the tragus, and/or within the auricle or fossa. Or, there may be additional acoustic transducers 1820 on or surrounding the ear in addition to acoustic transducers 1820 inside the ear canal. Having an acoustic transducer 1820 positioned next to an ear canal of a user may enable the microphone array to collect information on how sounds arrive at the ear canal. By positioning at least two of acoustic transducers 1820 on either side of a user's head (e.g., as binaural microphones), augmented-reality device 1800 may simulate binaural hearing and capture a 3D stereo sound field around about a user's head. In some embodiments, acoustic transducers 1820(A) and 1820(B) may be connected to augmented-reality system 1800 via a wired connection 1830, and in other embodiments acoustic transducers 1820(A) and 1820(B) may be connected to augmented-reality system 1800 via a wireless connection (e.g., a BLUETOOTH connection). In still other embodiments, acoustic transducers 1820(A) and 1820(B) may not be used at all in conjunction with augmented-reality system 1800.
Acoustic transducers 1820 on frame 1810 may be positioned in a variety of different ways, including along the length of the temples, across the bridge, above or below display devices 1815(A) and 1815(B), or some combination thereof. Acoustic transducers 1820 may also be oriented such that the microphone array is able to detect sounds in a wide range of directions surrounding the user wearing the augmented-reality system 1800. In some embodiments, an optimization process may be performed during manufacturing of augmented-reality system 1800 to determine relative positioning of each acoustic transducer 1820 in the microphone array.
In some examples, augmented-reality system 1800 may include or be connected to an external device (e.g., a paired device), such as neckband 1805. Neckband 1805 generally represents any type or form of paired device. Thus, the following discussion of neckband 1805 may also apply to various other paired devices, such as charging cases, smart watches, smart phones, wrist bands, other wearable devices, hand-held controllers, tablet computers, laptop computers, other external compute devices, etc.
As shown, neckband 1805 may be coupled to eyewear device 1802 via one or more connectors. The connectors may be wired or wireless and may include electrical and/or non-electrical (e.g., structural) components. In some cases, eyewear device 1802 and neckband 1805 may operate independently without any wired or wireless connection between them. While
Pairing external devices, such as neckband 1805, with augmented-reality eyewear devices may enable the eyewear devices to achieve the form factor of a pair of glasses while still providing sufficient battery and computation power for expanded capabilities. Some or all of the battery power, computational resources, and/or additional features of augmented-reality system 1800 may be provided by a paired device or shared between a paired device and an eyewear device, thus reducing the weight, heat profile, and form factor of the eyewear device overall while still retaining desired functionality. For example, neckband 1805 may allow components that would otherwise be included on an eyewear device to be included in neckband 1805 since users may tolerate a heavier weight load on their shoulders than they would tolerate on their heads. Neckband 1805 may also have a larger surface area over which to diffuse and disperse heat to the ambient environment. Thus, neckband 1805 may allow for greater battery and computation capacity than might otherwise have been possible on a stand-alone eyewear device. Since weight carried in neckband 1805 may be less invasive to a user than weight carried in eyewear device 1802, a user may tolerate wearing a lighter eyewear device and carrying or wearing the paired device for greater lengths of time than a user would tolerate wearing a heavy standalone eyewear device, thereby enabling users to more fully incorporate artificial-reality environments into their day-to-day activities.
Neckband 1805 may be communicatively coupled with eyewear device 1802 and/or to other devices. These other devices may provide certain functions (e.g., tracking, localizing, depth mapping, processing, storage, etc.) to augmented-reality system 1800. In the embodiment of
Acoustic transducers 1820(1) and 1820(J) of neckband 1805 may be configured to detect sound and convert the detected sound into an electronic format (analog or digital). In the embodiment of
Controller 1825 of neckband 1805 may process information generated by the sensors on neckband 1805 and/or augmented-reality system 1800. For example, controller 1825 may process information from the microphone array that describes sounds detected by the microphone array. For each detected sound, controller 1825 may perform a direction-of-arrival (DOA) estimation to estimate a direction from which the detected sound arrived at the microphone array. As the microphone array detects sounds, controller 1825 may populate an audio data set with the information. In embodiments in which augmented-reality system 1800 includes an inertial measurement unit, controller 1825 may compute all inertial and spatial calculations from the IMU located on eyewear device 1802. A connector may convey information between augmented-reality system 1800 and neckband 1805 and between augmented-reality system 1800 and controller 1825. The information may be in the form of optical data, electrical data, wireless data, or any other transmittable data form. Moving the processing of information generated by augmented-reality system 1800 to neckband 1805 may reduce weight and heat in eyewear device 1802, making it more comfortable to the user.
Power source 1835 in neckband 1805 may provide power to eyewear device 1802 and/or to neckband 1805. Power source 1835 may include, without limitation, lithium ion batteries, lithium-polymer batteries, primary lithium batteries, alkaline batteries, or any other form of power storage. In some cases, power source 1835 may be a wired power source. Including power source 1835 on neckband 1805 instead of on eyewear device 1802 may help better distribute the weight and heat generated by power source 1835.
As noted, some artificial-reality systems may, instead of blending an artificial reality with actual reality, substantially replace one or more of a user's sensory perceptions of the real world with a virtual experience. One example of this type of system is a head-worn display system, such as virtual-reality system 1900 in
Artificial-reality systems may include a variety of types of visual feedback mechanisms. For example, display devices in augmented-reality system 1800 and/or virtual-reality system 1900 may include one or more liquid crystal displays (LCDs), light emitting diode (LED) displays, microLED displays, organic LED (OLED) displays, digital light project (DLP) micro-displays, liquid crystal on silicon (LCoS) micro-displays, and/or any other suitable type of display screen. These artificial-reality systems may include a single display screen for both eyes or may provide a display screen for each eye, which may allow for additional flexibility for varifocal adjustments or for correcting a user's refractive error. Some of these artificial-reality systems may also include optical subsystems having one or more lenses (e.g., concave or convex lenses, Fresnel lenses, adjustable liquid lenses, etc.) through which a user may view a display screen. These optical subsystems may serve a variety of purposes, including to collimate (e.g., make an object appear at a greater distance than its physical distance), to magnify (e.g., make an object appear larger than its actual size), and/or to relay (to, e.g., the viewer's eyes) light. These optical subsystems may be used in a non-pupil-forming architecture (such as a single lens configuration that directly collimates light but results in so-called pincushion distortion) and/or a pupil-forming architecture (such as a multi-lens configuration that produces so-called barrel distortion to nullify pincushion distortion).
In addition to or instead of using display screens, some of the artificial-reality systems described herein may include one or more projection systems. For example, display devices in augmented-reality system 1800 and/or virtual-reality system 1900 may include micro-LED projectors that project light (using, e.g., a waveguide) into display devices, such as clear combiner lenses that allow ambient light to pass through. The display devices may refract the projected light toward a user's pupil and may enable a user to simultaneously view both artificial-reality content and the real world. The display devices may accomplish this using any of a variety of different optical components, including waveguide components (e.g., holographic, planar, diffractive, polarized, and/or reflective waveguide elements), light-manipulation surfaces and elements (such as diffractive, reflective, and refractive elements and gratings), coupling elements, etc. Artificial-reality systems may also be configured with any other suitable type or form of image projection system, such as retinal projectors used in virtual retina displays.
The artificial-reality systems described herein may also include various types of computer vision components and subsystems. For example, augmented-reality system 1800 and/or virtual-reality system 1900 may include one or more optical sensors, such as two-dimensional (2D) or 3D cameras, structured light transmitters and detectors, time-of-flight depth sensors, single-beam or sweeping laser rangefinders, 3D LiDAR sensors, and/or any other suitable type or form of optical sensor. An artificial-reality system may process data from one or more of these sensors to identify a location of a user, to map the real world, to provide a user with context about real-world surroundings, and/or to perform a variety of other functions.
The artificial-reality systems described herein may also include one or more input and/or output audio transducers. Output audio transducers may include voice coil speakers, ribbon speakers, electrostatic speakers, piezoelectric speakers, bone conduction transducers, cartilage conduction transducers, tragus-vibration transducers, and/or any other suitable type or form of audio transducer. Similarly, input audio transducers may include condenser microphones, dynamic microphones, ribbon microphones, and/or any other type or form of input transducer. In some embodiments, a single transducer may be used for both audio input and audio output.
In some embodiments, the artificial-reality systems described herein may also include tactile (i.e., haptic) feedback systems, which may be incorporated into headwear, gloves, body suits, handheld controllers, environmental devices (e.g., chairs, floormats, etc.), and/or any other type of device or system. Haptic feedback systems may provide various types of cutaneous feedback, including vibration, force, traction, texture, and/or temperature. Haptic feedback systems may also provide various types of kinesthetic feedback, such as motion and compliance. Haptic feedback may be implemented using motors, piezoelectric actuators, fluidic systems, and/or a variety of other types of feedback mechanisms. Haptic feedback systems may be implemented independent of other artificial-reality devices, within other artificial-reality devices, and/or in conjunction with other artificial-reality devices.
By providing haptic sensations, audible content, and/or visual content, artificial-reality systems may create an entire virtual experience or enhance a user's real-world experience in a variety of contexts and environments. For instance, artificial-reality systems may assist or extend a user's perception, memory, or cognition within a particular environment. Some systems may enhance a user's interactions with other people in the real world or may enable more immersive interactions with other people in a virtual world. Artificial-reality systems may also be used for educational purposes (e.g., for teaching or training in schools, hospitals, government organizations, military organizations, business enterprises, etc.), entertainment purposes (e.g., for playing video games, listening to music, watching video content, etc.), and/or for accessibility purposes (e.g., as hearing aids, visual aids, etc.). The embodiments disclosed herein may enable or enhance a user's artificial-reality experience in one or more of these contexts and environments and/or in other contexts and environments.
In some embodiments, the systems described herein may also include an eye-tracking subsystem designed to identify and track various characteristics of a user's eye(s), such as the user's gaze direction. The phrase “eye tracking” may, in some examples, refer to a process by which the position, orientation, and/or motion of an eye is measured, detected, sensed, determined, and/or monitored. The disclosed systems may measure the position, orientation, and/or motion of an eye in a variety of different ways, including through the use of various optical-based eye-tracking techniques, ultrasound-based eye-tracking techniques, etc. An eye-tracking subsystem may be configured in a number of different ways and may include a variety of different eye-tracking hardware components or other computer-vision components. For example, an eye-tracking subsystem may include a variety of different optical sensors, such as two-dimensional (2D) or 3D cameras, time-of-flight depth sensors, single-beam or sweeping laser rangefinders, 3D LiDAR sensors, and/or any other suitable type or form of optical sensor. In this example, a processing subsystem may process data from one or more of these sensors to measure, detect, determine, and/or otherwise monitor the position, orientation, and/or motion of the user's eye(s).
As noted, the eye-tracking systems or subsystems disclosed herein may track a user's eye position and/or eye movement in a variety of ways. In one example, one or more light sources and/or optical sensors may capture an image of the user's eyes. The eye-tracking subsystem may then use the captured information to determine the user's inter-pupillary distance, interocular distance, and/or a 3D position of each eye (e.g., for distortion adjustment purposes), including a magnitude of torsion and rotation (i.e., roll, pitch, and yaw) and/or gaze directions for each eye. In one example, infrared light may be emitted by the eye-tracking subsystem and reflected from each eye. The reflected light may be received or detected by an optical sensor and analyzed to extract eye rotation data from changes in the infrared light reflected by each eye.
The eye-tracking subsystem may use any of a variety of different methods to track the eyes of a user. For example, a light source (e.g., infrared light-emitting diodes) may emit a dot pattern onto each eye of the user. The eye-tracking subsystem may then detect (e.g., via an optical sensor coupled to the artificial reality system) and analyze a reflection of the dot pattern from each eye of the user to identify a location of each pupil of the user. Accordingly, the eye-tracking subsystem may track up to six degrees of freedom of each eye (i.e., 3D position, roll, pitch, and yaw) and at least a subset of the tracked quantities may be combined from two eyes of a user to estimate a gaze point (i.e., a 3D location or position in a virtual scene where the user is looking) and/or an IPD.
In some cases, the distance between a user's pupil and a display may change as the user's eye moves to look in different directions. The varying distance between a pupil and a display as viewing direction changes may be referred to as “pupil swim” and may contribute to distortion perceived by the user as a result of light focusing in different locations as the distance between the pupil and the display changes. Accordingly, measuring distortion at different eye positions and pupil distances relative to displays and generating distortion corrections for different positions and distances may allow mitigation of distortion caused by pupil swim by tracking the 3D position of a user's eyes and applying a distortion correction corresponding to the 3D position of each of the user's eyes at a given point in time. Thus, knowing the 3D position of each of a user's eyes may allow for the mitigation of distortion caused by changes in the distance between the pupil of the eye and the display by applying a distortion correction for each 3D eye position. Furthermore, as noted above, knowing the position of each of the user's eyes may also enable the eye-tracking subsystem to make automated adjustments for a user's IPD.
In some embodiments, a display subsystem may include a variety of additional subsystems that may work in conjunction with the eye-tracking subsystems described herein. For example, a display subsystem may include a varifocal subsystem, a scene-rendering module, and/or a vergence-processing module. The varifocal subsystem may cause left and right display elements to vary the focal distance of the display device. In one embodiment, the varifocal subsystem may physically change the distance between a display and the optics through which it is viewed by moving the display, the optics, or both. Additionally, moving or translating two lenses relative to each other may also be used to change the focal distance of the display. Thus, the varifocal subsystem may include actuators or motors that move displays and/or optics to change the distance between them. This varifocal subsystem may be separate from or integrated into the display subsystem. The varifocal subsystem may also be integrated into or separate from its actuation subsystem and/or the eye-tracking subsystems described herein.
In one example, the display subsystem may include a vergence-processing module configured to determine a vergence depth of a user's gaze based on a gaze point and/or an estimated intersection of the gaze lines determined by the eye-tracking subsystem. Vergence may refer to the simultaneous movement or rotation of both eyes in opposite directions to maintain single binocular vision, which may be naturally and automatically performed by the human eye. Thus, a location where a user's eyes are verged is where the user is looking and is also typically the location where the user's eyes are focused. For example, the vergence-processing module may triangulate gaze lines to estimate a distance or depth from the user associated with intersection of the gaze lines. The depth associated with intersection of the gaze lines may then be used as an approximation for the accommodation distance, which may identify a distance from the user where the user's eyes are directed. Thus, the vergence distance may allow for the determination of a location where the user's eyes should be focused and a depth from the user's eyes at which the eyes are focused, thereby providing information (such as an object or plane of focus) for rendering adjustments to the virtual scene.
The vergence-processing module may coordinate with the eye-tracking subsystems described herein to make adjustments to the display subsystem to account for a user's vergence depth. When the user is focused on something at a distance, the user's pupils may be slightly farther apart than when the user is focused on something close. The eye-tracking subsystem may obtain information about the user's vergence or focus depth and may adjust the display subsystem to be closer together when the user's eyes focus or verge on something close and to be farther apart when the user's eyes focus or verge on something at a distance.
The eye-tracking information generated by the above-described eye-tracking subsystems may also be used, for example, to modify various aspect of how different computer-generated images are presented. For example, a display subsystem may be configured to modify, based on information generated by an eye-tracking subsystem, at least one aspect of how the computer-generated images are presented. For instance, the computer-generated images may be modified based on the user's eye movement, such that if a user is looking up, the computer-generated images may be moved upward on the screen. Similarly, if the user is looking to the side or down, the computer-generated images may be moved to the side or downward on the screen. If the user's eyes are closed, the computer-generated images may be paused or removed from the display and resumed once the user's eyes are back open.
The above-described eye-tracking subsystems can be incorporated into one or more of the various artificial reality systems described herein in a variety of ways. For example, one or more eye-tracking system components may be incorporated into augmented-reality system 1800 in
The process parameters and sequence of the steps described and/or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and/or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed. The various exemplary methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.
The preceding description has been provided to enable others skilled in the art to best utilize various aspects of the exemplary embodiments disclosed herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the present disclosure. The embodiments disclosed herein should be considered in all respects illustrative and not restrictive. Reference should be made to any claims appended hereto and their equivalents in determining the scope of the present disclosure.
Unless otherwise noted, the terms “connected to” and “coupled to” (and their derivatives), as used in the specification and/or claims, are to be construed as permitting both direct and indirect (i.e., via other elements or components) connection. In addition, the terms “a” or “an,” as used in the specification and/or claims, are to be construed as meaning “at least one of.” Finally, for ease of use, the terms “including” and “having” (and their derivatives), as used in the specification and/or claims, are interchangeable with and have the same meaning as the word “comprising.”
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63/479,394, filed 11 Jan. 2023, and titled GRADIENT-INDEX LIQUID CRYSTAL LENS SYSTEM INCLUDING GUEST-HOST LIQUID CRYSTAL LAYER FOR REDUCING LIGHT LEAKAGE, the disclosure of which is incorporated, in its entirety, by this reference.
| Number | Date | Country | |
|---|---|---|---|
| 63479394 | Jan 2023 | US |
