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WO2025088074A1 - Dispositif à lentille optique - Google Patents

Dispositif à lentille optique Download PDF

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Publication number
WO2025088074A1
WO2025088074A1 PCT/EP2024/080148 EP2024080148W WO2025088074A1 WO 2025088074 A1 WO2025088074 A1 WO 2025088074A1 EP 2024080148 W EP2024080148 W EP 2024080148W WO 2025088074 A1 WO2025088074 A1 WO 2025088074A1
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WO
WIPO (PCT)
Prior art keywords
liquid crystal
region
crystal material
cell components
wall structure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/080148
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English (en)
Inventor
William Reeves
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Flexenable Technology Ltd
Original Assignee
Flexenable Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Flexenable Technology Ltd filed Critical Flexenable Technology Ltd
Publication of WO2025088074A1 publication Critical patent/WO2025088074A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
    • G02F1/294—Variable focal length devices
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/12—Fluid-filled or evacuated lenses
    • G02B3/14—Fluid-filled or evacuated lenses of variable focal length
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B2027/0178—Eyeglass type
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1339—Gaskets; Spacers; Sealing of cells
    • G02F1/13394—Gaskets; Spacers; Sealing of cells spacers regularly patterned on the cell subtrate, e.g. walls, pillars
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1339—Gaskets; Spacers; Sealing of cells
    • G02F1/13398—Spacer materials; Spacer properties
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2202/00—Materials and properties
    • G02F2202/40—Materials having a particular birefringence, retardation

Definitions

  • the present application relates to an optical lens device comprising concentric electrode patterns operable in parallel to electrically switch liquid crystal material at least in to and out of a first state comprising co-operative refractive index distributions in at least adjacent first and second concentric Fresnel regions centred on an optical axis, an assembly comprising the device and at least one optical element, and an apparatus comprising the device, a processor, a storage comprising instructions for controlling the device.
  • Fig. 8 shows, for comparison, a microscope image of the same device in a neutral "off' state in which no electric potential gradient is generated in the concentric electrode patterns.
  • the inventor for the present application has attributed the occurrence of these defects to the influence of the liquid crystal material in one Fresnel region on the liquid crystal material in an adjacent Fresnel region.
  • the inventor for the present application has worked on developing techniques to at least reduce the occurrence of such defects.
  • Fig. 1 shows a representation of an example of elements of a device according to an example
  • Fig. 2 shows a representation of an example of elements of a device according to an example
  • Fig. 3 shows a representation of an example of elements of a device according to an example
  • Fig. 4 shows a representation of an example of elements of a device according to an example
  • Fig. 5 shows a representation of an example of an arrangement of wall breaks according to an example
  • Figs. 6 and 7 show a representation of examples of radial resistance profiles for two concentric electrode patterns of Figs. 1 to 4;
  • Fig. 8 shows a representation of an example of defects observed in devices according to a preceding design
  • Fig. 9 illustrates a representation of an example of a theory about the cause of defects in devices according to a preceding design
  • Fig. 10 shows a representation of an example of a headset incorporating a liquid crystal, adaptive optical lens
  • Fig. 11 shows a representation of an example of a system for operating the headset of Fig. 10.
  • Fig. 12 shows schematically a representation of an example apparatus.
  • an optical lens device comprising: liquid crystal material contained between two half-cell components; wherein one or more of the two half-cell components comprises first and second concentric electrode patterns electrically operable in parallel to at least switch the liquid crystal material in to and out of a first state; wherein the first state comprises co-operative refractive index distributions in adjacent first and second regions centred on an optical axis; wherein at least one of the two half-cell components comprises at least one annular solid wall structure located in a reset region between a first edge of the first region and a second edge of the second region; and wherein the solid wall structure is: located closer to the first region than to the second region; and, in terms of refractive index for non-polarised light propagating in a direction perpendicular to the half-cell components, is more closely matched to the liquid crystal material at the first edge of the first region than to the liquid crystal material at the second edge of the second region, when the liquid crystal material is in the first state.
  • the liquid crystal material may be in the first state, the solid wall structure may be more closely matched to the liquid crystal material at the first edge of the first region than to the liquid crystal material at the second edge of the second region, also in terms of birefringence.
  • the spacer wall may at least partly comprise a polymerised reactive mesogen which has been polymerised in a state in which birefringence of the reactive mesogen most closely matches birefringence of the liquid crystal material at the first edge of the first region, when the liquid crystal material is in the first state.
  • the spacer wall may comprise a stack comprising at least one or more layers of the polymerised reactive mesogen and one or more layers of another material.
  • an optical lens device comprising: liquid crystal material contained between two half-cell components; wherein the two half-cell components comprise liquid crystal alignment layers that interface with the liquid crystal material, wherein the liquid crystal alignment layers are unidirectionally rubbed in a first direction; wherein one or more of the two half-cell components comprises first and second concentric electrode patterns operable in parallel to at least switch the liquid crystal material in to and out of a first state; wherein the first state comprises co-operative refractive index distributions in first and second regions centred on an optical axis; wherein at least one of the two half-cell components comprises at least one solid annular wall structure centred on the optical axis and located in a reset region between the first and second regions; and wherein the solid wall structure defines breaks for the liquid crystal material to radially move from one side of the solid wall structure to the opposite side of the solid wall structure, wherein the breaks are at least disproportionately located in one or more positions at which the reset region is oriented tangentially at an angle of less than about 65 degrees relative to the first
  • the breaks may be exclusively located in one or more positions at which the reset region is oriented tangentially at an angle of less than about 65 degrees relative to the first direction.
  • an example architecture for a Fresnel diffractive lens device comprises liquid crystal (LC) material 2 contained between two planar half-cell components 4, 6.
  • LC liquid crystal
  • One of the half-cell components 4 comprises a patterned conductor layer 16 defining a plurality of concentric electrode patterns 10, 12.
  • the concentric electrode patterns 10, 12 are centred on an optical axis 14 of the device, and are electrically operable in parallel.
  • Each electrode pattern 10, 12 defines a respective Fresnel set of concentric ring electrodes (not shown) connected in electrical series within the set.
  • the other of the two half-cell components 6 comprises a conductor layer 18 defining one or more counter electrodes.
  • the drawings show only two concentric electrode patterns 10, 12, but the device may comprise more than two concentric electrode patterns, all electrically operable together in parallel.
  • the two-half cell components 4, 6 also comprise uni-directionally rubbed alignment layers 20, 22 that interface with the LC material 2. Rubbing is a commonly used technique to produce LC alignment layers from solid polymer layers such as e.g. solid polyimide layers.
  • At least one of the two half-cell components 4, 6 comprises one or more annular solid wall structures 24 centred on the optical axis 14 of the device and in one more reset regions 26 between adjacent electrode patterns.
  • the device may comprise other elements not shown in Figs. 1 and 2, such as: column-shaped spacers located in the regions of the concentric electrode patterns 10, 12 for better maintaining a uniform thickness of LC material across the active region of the device bounded by the outer edge of the outermost concentric electrode pattern 12; and adhesive seals to secure the two half-cell components 4, 6 together, and laterally contain the LC material 2.
  • the annular solid wall structure 24 may also assist the maintenance of a uniform thickness of LC material 2 across the active region of the device bounded by the outer edge of the outermost concentric electrode pattern 12.
  • Each Fresnel set of concentric ring electrodes (defined by a respective one of the concentric electrode patterns) comprises a plurality of concentric ring electrodes with resistive links between the concentric ring electrodes.
  • Each set is configured such that, upon application of a potential difference across the sets in parallel, the sets induce cooperative refractive index (Rl) distributions in respective radially inner and outer concentric regions of the LC material 2.
  • This state is referred to below as a "first state" of the LC material.
  • the co-operative refractive index (Rl) distributions may comprise confocal Rl distributions (which provide substantially confocal optical path length (OPL) profiles) that exhibit substantially the same focal length.
  • the concentric electrode patterns 10, 12 are configured to be connected in parallel to a power source (via bus bars 28, 30 and via holes 32 in an insulator layer (not shown) between the electrode layer 16 defining the concentric electrode patterns 10, 12 and a conductor layer defining the bus bars 28, 30), so as to apply substantially the same potential difference (V1 -V2) across each concentric electrode pattern 10, 12 in the same radial direction.
  • Figures 6 and 7 show examples of radial resistance profiles (electrical resistance against distance from common axis 14) for the concentric electrode patterns 10, 12.
  • the electrical potential of the counter electrode provided by the opposing half-cell component 6 is referred to below as V3.
  • the solid wall structure 24 is located closer to one of the concentric electrode patterns 10 than to the other of the concentric electrode patterns 12.
  • the LC material 2 at the radially outer edge of the inner concentric electrode pattern 10 is different in terms of refractive index (for non-polarised light propagating in a direction perpendicular to the half-cell components 4, 6) to the LC material 2 at the radially inner edge of the adjacent outer concentric electrode pattern 12, because the electric potential difference (difference between V3 and V1 ) across the LC material 2 at the radially outer edge of the inner concentric electrode pattern 10 is different to the electric potential difference (difference between V3 and V2) across the LC material 2 at the radially inner edge of the adjacent outer concentric electrode pattern 12.
  • the annular solid wall structure 24 When the LC material is in the above-mentioned first state, the annular solid wall structure 24 more closely matches the LC material 2 at the radially outer edge of the inner concentric electrode pattern 10 than the LC material 2 atthe radially inner edge ofthe adjacent outer concentric electrode pattern 12, in terms of refractive index for non-polarised visible light propagating in a direction perpendicular to the plane of the two half-cell components 4, 6.
  • the LC material 2 exhibits birefringence, and at least part of the annular solid wall structure 24 may also exhibit birefringence.
  • the refractive index exhibited by the annular solid wall structure 24 for non-polarised light propagating in a direction perpendicular to the plane of the halfcell components 4, 6 may be different to the refractive index exhibited by the annular solid wall structure 24 for non-polarised light propagating in a direction parallel to the plane of the half-cell components 2, 6.
  • the annular solid wall structure 24 may at least partly comprise a polymerised reactive mesogen.
  • a reactive mesogen refers here to a polymerizable liquid crystal monomer material.
  • the reactive mesogen may adopt a plurality of different states, and the annular solid wall structure 24 may be at least partly formed by polymerising the reactive mesogen in situ on the half-cell component with the reactive mesogen in the one of the states thereof that most closely matches the LC material 2 at the outer radial edge of the inner concentric pattern 10 (when the LC material 2 is in the above-mentioned first state), in terms of refractive index exhibited for non-polarised light propagating in a direction perpendicular to the plane of the planar half-cell components 4, 6.
  • the solid wall structure 24 may comprise a stack (in the direction perpendicular to the plane of the first and second half-cell components 4, 6) of the above-mentioned polymerised reactive mesogen layer and one or more layers of one or more other materials.
  • the annular solid wall structure may define one or more breaks 34 via which liquid crystal material may move radially from one side of the solid wall structure 24 to the other side of the solid wall structure 24.
  • the breaks 34 are located at least disproportionately in regions (region from B to D via C and region from H to F via G in Fig. 4) in which the reset region 26 is oriented tangentially at an angle of less than about 65 degrees relative to the direction in which the alignment layers are unidirectionally rubbed.
  • each break 34 may have substantially the same dimension, and more breaks are then located in regions in which the reset region 26 is oriented tangentially at an angle of less than about 65 degrees relative to the rubbing direction than in regions in which the reset region 26 is oriented tangentially at an angle of more than about 65 degrees relative to the rubbing direction (region from H to B via A and region from D to F via E in Fig. 4).
  • the inventor for the present application has observed for the above- mentioned preceding design of lens device (without a solid annular wall structure in the reset region) that the occurrence of disinclination lines is least observed in regions at which the reset region is oriented parallel to the rubbing direction; and the above- mentioned technique of locating breaks at least disproportionately in regions in which the annular solid wall structure is oriented tangentially at an angle of less than about 65 degrees relative to the rubbing direction can achieve good reduction of the occurrence of disinclination lines, while allowing the radial movement of LC material from one side of the solid wall structure 24 to the other side of the solid wall structure 24.
  • the breaks 34 are exclusively located in in regions in which the reset region 26 is oriented tangentially at an angle of less than about 65 degrees relative to the rubbing direction.
  • Fig. 5 shows a representation of one example of locating the breaks 34 exclusively in regions in which the reset region 26 is oriented tangentially at an angle of less than about 65 degrees relative to the rubbing direction.
  • the breaks 34 have substantially the same dimension and are distributed evenly in the regions in which the reset 26 is oriented tangentially at an angle of less than about 65 degrees relative to the rubbing direction.
  • the inventor for the present application believes that the above-mentioned disinclination lines for the device according to the preceding design (without a spacer wall structure in the reset region(s)) are caused by the influence of LC material in a region of highest applied electric field on liquid crystal material in an adjacent region of lowest applied electric field; and that this influence has its greatest impact in regions in which the reset region is oriented tangentially at an angle of 90 degrees to the rubbing direction.
  • the inventor for the present application believes that the disinclination lines occur where such influence of LC material in one Fresnel region on LC material in an adjacent Fresnel region results in a sharp change in LC director in part of a Fresnel region.
  • the solid wall structure 24 in the reset region 26 can reduce the influence of LC material in a region of highest applied electric field on LC material in an adjacent region of lowest applied electric field.
  • the liquid crystal device described above may, for example, function as or be used within a switchable lens device or a beam steering device.
  • a device may be or comprise an adaptive optical lens comprising a liquid crystal device according to any of the examples herein.
  • Such a device may be or comprise a headset, which may be referred to as a head-mounted display (HMD).
  • HMD head-mounted display
  • the liquid crystal device described above is useful in a wide range of applications, including ophthalmic lenses (such as spectacle lenses), virtual reality (VR), mixed reality (MR) and augmented reality (AR) headsets; optical projectors; photographic devices; and communication devices.
  • ophthalmic lenses such as spectacle lenses
  • VR virtual reality
  • MR mixed reality
  • AR augmented reality
  • the LC optical lens device may be used for the push lens and/or the pull lens or a combined push/pull lens of an augmented reality (AR) headset such as e.g. that shown in Fig. 10.
  • AR augmented reality
  • the headset 40 comprises a support frame 42 supporting optical components arranged in optical series in front of the user eye.
  • At least one optical component such as one or more of the optical components shown in Fig. 10 may be considered to correspond to or be part of an assembly, which may be considered to be a display stack, comprising at least one liquid crystal cell according to examples herein.
  • an assembly includes a stack of liquid crystal cells according to examples herein.
  • the push lens 48a includes at least one stack of liquid crystal cells
  • the pull lens 48b includes at least one stack of liquid crystal cells
  • the assembly includes the push lens 48a, the waveguide 50, the pull lens 48b, the variable dimmer device 46, which is an example of a luminance adjustment component, and the front window/lens 44.
  • Liquid crystal cells of a stack may be aligned along a common optical axis.
  • optical axes of at least two ofthe liquid crystal cells of a stack may be offset from each other in a direction parallel to a plane of a radial electrode pattern of at least one of the liquid crystal cells, provided that light traversing the assembly traverses the liquid crystal cells of the stack.
  • Fig. 10 only shows the optical components for one half of the headset for clarity of representation, but a matching set of optical components is also provided for the other half of the headset.
  • the waveguides 50 of the headset respectively display left-and right perspectives of one or more virtual reality objects, by which the user perceives the one or more virtual reality objects as 3D objects.
  • other mechanisms may be employed to display the left/right perspectives of the one or more virtual reality objects, such as e.g. laser projection.
  • the degree to which the user's left and right eyes need to rotate relative to each other such that the left and right perspectives of a virtual reality object are simultaneously directed onto the foveas (which are the parts of the retina responsible for sharp central vision necessary for activities for which visual detail is of primary importance) of respective left and right eyes of the user determines the distance at which the user perceives the virtual reality object to be.
  • This mechanism is referred to as vergence.
  • the LC optical lens device described above may be used as an adaptive lens device to control the location at which the user's eyes perceive the left/right perspectives of a displayed virtual reality object in focus (i.e. not blurred), which location may be referred to as a focal plane.
  • the LC optical lens device described above may be used as an adaptive lens device to control the degree to which the lenses in the user's eyes need to adapt to perceive the left and right perspectives of the virtual reality object in focus (i.e. not blurred). This adaptation mechanism of the lenses in the user's eyes is known as accommodation.
  • the LC optical lens device described above may be used to produce optical images (real or virtual) of the left/right perspectives of a virtual reality object substantially at the distance from the user's eyes at which the user perceives the virtual reality object to be located through the vergence mechanism discussed above. This may allow the user to perceive a focussed 3D image of the virtual reality object without disrupting the vergenceaccommodation reflex, by which the focussing action of the lenses in the user's eyes (accommodation) is unconsciously linked to the above-mentioned rotation of the left and right eyes relative to each other (vergence).
  • the LC optical lens device may be used to avoid or reduce the strain on the user's eyes that can arise from a conflict between the vergence and accommodation mechanisms (referred to as the vergenceaccommodation conflict).
  • the LC optical lens device may be switchable between a positive focal power and a negative focal power.
  • a liquid crystal device may provide a lower complexity and/or higher quality system to actively adjust focus to compensate for focal differences between a virtual object and a real-world environment visible to a user of a headset through the optical components mounted in front of each eye. This for example allows the perceived and actual image depth to be brought together in a consistent manner, improving user comfort.
  • the headset 40 permits transmission of light from a real-world environment around the headset 40 at least partly through the optical components and into the user's eyes.
  • the optical components are at least partly transparent.
  • the luminance of the environment may be significantly higher outdoors than indoors, such as around 100 times higher. This can lead to a virtual object appearing washed out and difficult to see when the user operates the headset outdoors, unless the luminance of the light transmitted from the environment to the user is appropriately controlled.
  • the variable dimmer device 46 controls the amount of light transmitted through the optical components and towards the eyes, e.g. so as to reduce the luminance of light from the environment transmitted towards the user in bright conditions, and may be used to provide ambient dimming to dim ambient light transmitted through the headset 40.
  • the variable dimmer device 46 may provide so-called global dimming, in which the luminance of the light from the environment is adjusted by substantially the same amount within an extent of a plane of the variable dimmer device 46 facing the user (e.g. to reduce the luminance of the light by substantially the same amount across an entire surface area of the variable dimmer device 46).
  • global dimming can allow the luminance of the light transmitted through the variable dimmer device 46 to be controlled in a substantially spatially uniform manner (e.g. so as to provide a substantially spatially uniform reduction in the luminance across a field of view of the user).
  • the variable dimmer device 46 may also or alternatively provide local dimming, in which the variable dimmer device 46 is adjustable to control the luminance of the light transmitted from the environment on an area-by-area basis (where an area may correspond to a single pixel or a plurality of pixels). Local dimming may involve adjusting the luminance across less than all of the surface area of the variable dimmer device 46, such as within a sub-area which is smaller than the surface area of the variable dimmer device 46. In other cases, though, local dimming may involve adjusting the luminance across the entire surface area of the variable dimmer device 46 but by different amounts in at least two portions of the surface area.
  • the headset 40 may be configured to obtain luminance data, e.g. from a light sensor of the headset 40, indicative of the luminance of the light within the environment of the headset 40.
  • luminance data e.g. from a light sensor of the headset 40
  • the headset 40 may include a light sensor to detect the luminance of light at a second side 49b of the headset 40, opposite to the first side 49a.
  • the variable dimmer device 46 may be controlled at least partly based on the luminance data, so as to adjust the luminance of light transmitted from the second side of the headset 40 towards the user, to improve the visibility of the virtual object displayed to the user by the headset 40.
  • a first lens comprising at least one liquid crystal cell stack of the examples herein (the push lens 48a) is located between the waveguide 50 and the eye, with the headset 40 in use.
  • Light representative of the virtual object is generated and transmitted to the waveguide 50, which directs the light through the push lens 48a and into the eye.
  • the push lens 48a has a focusing effect to focus the light representative of the virtual object so that the object appears in focus to the user.
  • the virtual object may be generated so that it is in focus at a focal plane of infinity.
  • the push lens 48a may then bring the virtual object into focus at a focal plane which is closer to the user than infinity, to allow the user to focus on the virtual object more comfortably.
  • the focal plane at which the virtual object is to be brought into focus, and hence the focusing power to be applied by the push lens 48a may be determined based on eye tracking data, e.g. obtained by a suitable sensor as discussed further below, which is indicative of a direction in which the eye of the user is looking.
  • the headset 40 of Filg. 10 includes a second lens (the pull lens 48b) positioned at an opposite side of the waveguide 50 to the push lens 48a.
  • the pull lens 48b applies an appropriate focusing effect to light from the environment traversing the pull lens 48b to at least partially compensate for or otherwise reduce the focusing effect introduced by the push lens 48a.
  • the push and pull lenses 48a, 48b may provide opposite focusing effects to each other, e.g. with substantially equal magnitudes but opposite signs.
  • one of the push and pull lenses 48a, 48b may provide a positive focusing power and the other one of the push and pull lenses 48a, 48b may provide a negative focusing power, which may be substantially equal in magnitude.
  • At least one lens of examples herein each includes a so-called doublet of liquid crystal cells according to examples herein.
  • a doublet is a stack of two liquid crystal cells.
  • the focusing effect of a liquid crystal-based lens may depend on the polarization of the light incident on the lens. Rather than using a separate polarizer component, using a doublet such as this may provide an appropriate focusing effect with improved light transmission; in some examples this is achieved by positioning one liquid crystal cell of the doublet orthogonal to the other liquid crystal cell of the doublet, with respect to the respective orientation of polarization that each liquid crystal cell is configured to modify light for.
  • FIG. 10 shows an example of a push lens 48a and a pull lens 48b in combination with various other optical components. It is to be appreciated that a liquid crystal cell in accordance with examples herein can be used in combination with different optical component(s) than those shown in Fig. 10, to provide further flexibility in functionality. This may further reduce the size and/or weight of apparatus including the liquid crystal cell and/or improve optical performance of the apparatus.
  • an assembly such as a display stack, including a liquid crystal cell in accordance with examples herein may include a reflection-reduction layer (such as an anti-reflection (AR) coating), which may be laminated to another optical component of the assembly, such as the front window/lens 44, and/or a protective layer (such as a hard coat) to protect the assembly from damage, e.g. due to abrasion, and/or wear due to exposure to environmental conditions.
  • a reflection-reduction layer such as an anti-reflection (AR) coating
  • AR anti-reflection
  • a protective layer such as a hard coat
  • the liquid crystal device comprises electrical terminals electrically connected to the busbars.
  • the electrical terminals for example allow a potential difference to be applied across the busbars, and thus across each set of concentric rings.
  • the electrical potential applied to an electrical terminal can be controlled by a suitable control system.
  • a system 55 comprises a processor operating on the basis of computer program code stored in a memory 52 to control an image generation driver chip 53 to cause an image generation system to generate images of I eft/right perspectives of one or more virtual reality objects, by which the user may perceive 3D images of the virtual reality objects, and display the images via the waveguide 50.
  • Fig. 11 there may be two waveguides: one to display an image of a left perspective of a virtual reality object to a left eye and another to display an image of a right perspective of a virtual reality object to a right eye, as discussed further with reference to Fig. 11.
  • An image generation system is discussed further below with reference to Fig. 12.
  • Inputs from sensors feed into the processor to enable the processor to control positions at which the virtual reality objects are displayed by the waveguides 50, for seamless overlay of the one or more virtual reality objects into the user's view of the user's real environment.
  • the processor 51 controls the adaptive lens driver chip 38 to achieve the optical focussing power (Dioptres) required to achieve the above-described generation of optical images of the display output of the waveguides at a distance from the user's eyes at which the virtual content that the user is determined to be looking at (e.g. through tracking of the user's eyes) is intended to be perceived by the user (through the vergence mechanism described above).
  • a driver chip is an example of a controller, which may be implemented in hardware, e.g. via suitably configured circuitry. In some cases, a driver chip may include or be considered to implement at least one processor.
  • Fig. 12 illustrates schematically hardware architecture of an apparatus 60 according to further examples.
  • the apparatus 60 comprises at least one liquid crystal cell stack in accordance with examples herein.
  • the apparatus 60 is configured to be mounted on human head, e.g. a head of a user, with a liquid crystal cell stack positioned in a field of view of an eye of the head, in use.
  • the apparatus 60 is an AR headset for displaying a virtual image to a wearer of the headset, and may be similar to or the same as the headset 40 of Fig. 10.
  • apparatus including a similar hardware architecture to the apparatus 60 of Fig. 12 may be configured for a different purpose, may include additional components and/or may omit at least one of the components illustrated in Fig. 12.
  • the apparatus 60 of Fig. 12 includes an optical system 62, an image generation system 64, at least one processor 66, storage 68, at least one sensor 70, a user input/output interface 72, a communications system 74 and at least one further hardware system 76.
  • Components of the apparatus 60 are connected to each other via at least one bus 78, which may be or include any suitable interface or bus for transferring data between the illustrate components.
  • the optical system 62 includes a first assembly and a second assembly, which in this example are a first display stack 62a and a second display stack 62b, respectively.
  • the first display stack 62a comprises a first set of optical components, e.g. arranged as a stack of layers.
  • the apparatus 60 is configured to permit at least partial transmission of light from an external environment through the first display stack 62a and towards a first eye of the user, with the apparatus 60 in use and mounted on the head.
  • the first display stack 62a is arranged for directing light from the second side towards the first eye (in this case, through the first display stack 62a).
  • the first display stack 62a in this case includes the optical components shown in Fig. 10, i.e. the push lens 48a, the waveguide 50, the pull lens 48b (where the push and pull lenses 48a, 48b are each an example of a liquid crystal device according to examples herein), the variable dimmer device 46 and the front window/lens 44.
  • the push lens 48a and/or the pull lens 48b of the first display stack 62a may be considered to be a first lens comprising a first at least one of the liquid crystal cell stacks according to examples herein.
  • the first lens is configured to be positioned in a first field of view of a first eye, e.g. the first eye of a user, in use.
  • the second display stack 62b comprises a second set of optical components, which in this example is the same as the first set of optical components but configured to transmit light towards a second eye of the user, with the apparatus 60 in use.
  • the second display stack 62b is arranged to direct light from the second side of the apparatus 60 towards the second eye.
  • the push lens and/or the pull lens of the second display stack 62b may be considered to be a second lens comprising a second at least one of the liquid crystal cell stacks according to examples herein.
  • the second lens is configured to be positioned in a second field of view of a second eye, e.g. the second eye of the user, in use.
  • the first lens may be visible to solely the first eye or to both the first and second eye, in use
  • the second lens may be visible to solely the second eye or to both the first and second eye, in use.
  • a spatial arrangement of elements of the second display stack 62b in at least one layer of the stack may mirror the spatial arrangement of corresponding elements of the first display stack 62a in the corresponding layer of the stack of the first optical arrangement 62a as reflected in a sagittal plane of the apparatus 60 (which may be referred to as a longitudinal plane of the apparatus 60, and e.g. separates left and right sides of the apparatus, with the apparatus in use).
  • a sagittal plane of the apparatus 60 which may be referred to as a longitudinal plane of the apparatus 60, and e.g. separates left and right sides of the apparatus, with the apparatus in use.
  • the first and second display stacks 62a, 62b may have a different structure from each other.
  • the optical system 62 may include further components, e.g. further optical components, not shown in Fig. 12.
  • the apparatus 60 also includes an image generation system 64 to generate an image of a virtual object to be displayed to the user of the apparatus 60 so that the virtual object appears to the user to be overlaid on top of the external environment, which is at least partly visible to the user through the optical system 62.
  • the image generation system 64 may be or include a display device to generate an image (e.g. of a virtual object) for display by the apparatus 60 to the user.
  • the display device may be a liquid crystal display (LCD) device, a light emitting diode (LED) display device such as an organic light emitting diode (OLED) display device, an electroluminescent (EL) display device and so forth.
  • the image generation system 64 is in optical communication with the optical system 62.
  • the image generation system 64 may be housed by the support frame 42 if the apparatus 60 is in the form of the headset 40 of Fig. 10.
  • Light generated by the image generation system 62 representing the virtual object may be transmitted to the optical system (e.g. to a waveguide such as the waveguide 50 shown in Fig. 10) either directly (e.g. without traversing another optical component) or via at least one further optical component.
  • the image generation system may include two display devices, a first one for the first eye and a second one for the second eye, e.g. if it is desired to display a first image to the first eye and a second image to the second eye.
  • a single display device may be used to generate an image to be displayed to both the first and second eyes.
  • the image generation system 64 is shown as a separate system from the optical system 62. In other examples, though, the image generation system may form part of the optical system.
  • an assembly, such as a display stack, of the optical system may include an image generation system, such as a display device.
  • the at least one processor 66 of the apparatus 60 may be a single processor or a plurality of processors of one or more types. Components of the at least one processor 66 may be implemented using suitably programmed hardware, e.g. in the form of circuitry.
  • the at least one processor 66 may include a central processing unit (CPU), a graphics processing unit (GPU) and/or a neural processing unit (NPU), which may be referred to as a neural network accelerator.
  • CPU central processing unit
  • GPU graphics processing unit
  • NPU neural processing unit
  • apparatus such as the apparatus 60 of Fig. 12, includes driving circuitry connected to at least one electrical connection connected to the electrode patterns of the liquid crystal cell stack to apply a potential difference across one or more electrode sets of the liquid crystal cells of the liquid crystal cell stack.
  • the potential difference applied (such as a magnitude and/ortiming of the potential difference applied) may be determined by the at least one processor 66 and/or by the driving circuitry, such as by a controller implemented by at least a portion of the driving circuitry, based on the instructions stored in the storage.
  • the determination of the potential difference may be instigated by instructions received from the at least one processor, such as instructions indicative that a virtual object is to be displayed and that one or more electrode sets are thus to be activated so that the virtual object appears in focus to the user.
  • the driving circuitry may be agnostic to the at least one processor from which the instructions are received.
  • the operation of the driving circuitry may for example be independent of the at least one processor used to control the driving circuitry, such that the same effect can be achieved irrespective of the at least one processor coupled to the driving circuitry (provided the at least one processor provides an appropriate indication to the driving circuitry to cause the driving circuitry to determine a suitable potential difference).
  • the potential difference may be applied to the electrical connection(s) by at least one driver of the driving circuitry, such as the adaptive lens driver chip 38 of Fig. 11, which is an example of a driver.
  • Application of a potential difference by the at least one driver may be considered to amount to so-called “driving" of the electrode pattern(s), via the electrical connection(s).
  • the driving circuitry may be in the form of at least one system- on-a-chip (SoC).
  • the storage 68 may be or include computer-useable volatile and/or non-volatile memory.
  • the storage 68 may comprise random access memory (RAM) and/or read-only memory (ROM).
  • the storage 68 may be removable or non-removable from the apparatus 60.
  • the storage 68 stores instructions for controlling the apparatus 60 in accordance with examples herein, e.g. to activate one or more electrode sets of the liquid crystal cells of the liquid crystal cell stack. Activation of an electrode set for example refers to applying a potential difference between at least two connectors connected to the electrode set.
  • the instructions may be in the form of computer-readable and/or executable instructions, e.g. computer program instructions.
  • the storage 68 is shown as a separate component to the at least one processor 66 in Fig. 12, in some cases the storage 68 may be or include internal storage of the at least one processor 66, in which cases the at least one processor 66 and the storage 68 may be at least partly integrated into the same system or component.
  • the at least one sensor 70 in this example is configured to obtain eye tracking data of the apparatus, in use, which for example indicates a direction in which at least one eye of the user is looking, as the skilled person will appreciate. Eye tracking data may be obtained for each eye, or the eye tracking data may be obtained for a single eye or for a combination of both eyes of the user.
  • Suitable sensors for obtaining eye tracking data include a camera 70a for obtaining images of at least one eye of the user, an inertial measurement unit (IMU) 70b for determining an orientation of the apparatus 60 and at least one position sensor 70c such as a global positioning system (GPS) sensor to determine a location of the apparatus 60.
  • IMU inertial measurement unit
  • GPS global positioning system
  • an IMU 70b may include at least one accelerator or gyroscope for use in determining the orientation of the apparatus 60.
  • the focusing effect of the at least one liquid crystal cell may be controlled based on the eye tracking data, e.g. so as to reduce user eye strain as described further above.
  • the apparatus 60 also includes a user input/output interface 72 via which a user can interact with the apparatus 60 to control aspects of the apparatus 60.
  • the user input/output interface 72 may be or include an input device such as a button, a touchscreen, a slider, a controller or any other suitable device for communicating user requests to the apparatus 60 to control the apparatus 60.
  • the apparatus 60 includes a communications system 74 for receiving data from a remote system, e.g. via a suitable telecommunications network, such as a wireless network, or via some other type of network or connection.
  • the communications system 74 may include an input/output interface, such as a Bluetooth connector, a universal serial bus (USB) connector or a network connector, for receiving the data from the remote system.
  • the apparatus 60 of Fig. 12 includes at least one further hardware system 76 such as a power source, e.g. a battery, for providing electrical power to the electrical components of the apparatus 60.
  • a power source e.g. a battery
  • substantially used herein may be considered to mean that two elements that are “substantially” the same are: the same within manufacturing tolerances, the same within measurement uncertainties and/or are within 5% of each other.
  • liquid crystal (LC) material examples herein refer to a liquid crystal (LC) material.
  • a liquid crystal material is an example of a material with a switchable refractive index, or a refractive index changing material.
  • the described device, assembly and apparatus has use in example implementations other than tuneable lens and optical components.
  • Other example implementations include, but are not limited to: image generation systems, read only memory, network connections, USB, Bluetooth systems etc., methods of powering and associated techniques.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Liquid Crystal (AREA)

Abstract

Est divulgué un dispositif à lentille optique comprenant : un matériau à cristaux liquides contenu entre deux composants de demi-cellule; un ou plusieurs des deux composants de demi-cellule comprenant des premier et second motifs d'électrode concentriques pouvant fonctionner électriquement en parallèle pour au moins commuter le matériau à cristaux liquides dans et hors d'un premier état; le premier état comprenant des distributions d'indice de réfraction coopérantes dans des première et seconde régions adjacentes centrées sur un axe optique; au moins l'un des deux composants de demi-cellule comprenant au moins une structure de paroi solide annulaire située dans une région de réinitialisation entre un premier bord de la première région et un second bord de la seconde région; et la structure de paroi solide étant : située plus près de la première région que de la seconde région; et, en termes d'indice de réfraction pour la lumière non polarisée se propageant dans une direction perpendiculaire aux composants de demi-cellule, est plus étroitement adaptée au matériau à cristaux liquides au niveau du premier bord de la première région que du matériau à cristaux liquides au niveau du second bord de la seconde région, lorsque le matériau à cristaux liquides est dans le premier état.
PCT/EP2024/080148 2023-10-26 2024-10-24 Dispositif à lentille optique Pending WO2025088074A1 (fr)

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Application Number Priority Date Filing Date Title
GBGB2316387.6A GB202316387D0 (en) 2023-10-26 2023-10-26 Optical lens device
GB2316387.6 2023-10-26

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WO2025088074A1 true WO2025088074A1 (fr) 2025-05-01

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010055145A1 (en) * 2000-01-14 2001-12-27 Masataka Hamada Variable focal position spatial modulation device
TW200928445A (en) * 2007-12-18 2009-07-01 Univ Nat Chunghsing Liquid crystal lens with multiple modes
WO2017197533A1 (fr) * 2016-05-20 2017-11-23 Lensvector Inc. Dispositif à lentille de fresnel à couches plates de cristaux liquides
WO2019179147A1 (fr) * 2018-03-19 2019-09-26 京东方科技集团股份有限公司 Cellule à cristaux liquides et son procédé d'excitation, et lentille à cristaux liquides
US11360346B2 (en) * 2020-08-27 2022-06-14 Samsung Electronics Co., Ltd. Optical lens having a tunable focal length and display device including the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010055145A1 (en) * 2000-01-14 2001-12-27 Masataka Hamada Variable focal position spatial modulation device
TW200928445A (en) * 2007-12-18 2009-07-01 Univ Nat Chunghsing Liquid crystal lens with multiple modes
WO2017197533A1 (fr) * 2016-05-20 2017-11-23 Lensvector Inc. Dispositif à lentille de fresnel à couches plates de cristaux liquides
WO2019179147A1 (fr) * 2018-03-19 2019-09-26 京东方科技集团股份有限公司 Cellule à cristaux liquides et son procédé d'excitation, et lentille à cristaux liquides
US11360346B2 (en) * 2020-08-27 2022-06-14 Samsung Electronics Co., Ltd. Optical lens having a tunable focal length and display device including the same

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