Optical dimming device with chiral ferroelectric nematic liquid crystals

Abstract

An optical device includes a first electrode, and a medium including a ferroelectric liquid crystal and a chiral dopant. The medium is located adjacent to the first electrode. The optical device may also include a second electrode different from and spaced apart from the first electrode. The optical device may be used as an optical dimming device that controls an amount of light passing through the optical device based on a voltage gradient provided to the optical device.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 404,118, filed on September 6, 2022, entitled “Optical dimming device with chiral ferroelectric nematic liquid crystal,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to optical devices and, more particularly, to optical devices having ferroelectric liquid crystals. Background Art

[0004] Electro-optical devices are widely used in optical applications. By providing the ability to modulate light based on an applied electrical signal, an electro-optical device can be used, for example, to turn the transmission of light on or off. Additionally or alternatively, an electro-optical device can be used to modify the optical properties of light, such as polarization or spectral power distribution.

[0005] Some electro-optic devices may include liquid crystals. The liquid crystals are arranged based on an electric field applied to the electro-optic device. Based on the arrangement of the liquid crystals, the electro-optic device modifies the optical properties of light. Summary of the invention

[0006] However, there is a need to improve switching speed (e.g., the speed of switching from an “on” state to an “off” state or vice versa), dynamic ratio (e.g., the ratio of transmittance when the optical device is in the “on” state to the transmittance when the optical device is in the “off” state), and power consumption.

[0007] This application describes an optical device that utilizes ferroelectric liquid crystals to provide high switching speeds and high dynamic ratios. The disclosed device can operate at low electric fields, which reduces power consumption. When operated using batteries, the device has a longer battery life than traditional electro-optical devices.

[0008] According to some embodiments, an optical device includes a first electrode and a medium including a ferroelectric liquid crystal and a chiral dopant. The medium is located adjacent to the first electrode.

[0009] In some embodiments, the first electrode is transparent.

[0010] In some embodiments, the optical device includes a second electrode that is different from the first electrode and is spaced apart from the first electrode.

[0011] In some embodiments, the second electrode is transparent.

[0012] In some embodiments, the first electrode extends along a first plane and the second electrode extends along a second plane that is parallel to and offset from the first plane.

[0013] In some embodiments, the first electrode and the second electrode extend along a common plane.

[0014] In some embodiments, the first electrode is spaced apart from the second electrode by at least 20 μm.

[0015] In some embodiments, the optical device includes a first substrate positioned adjacent to the first electrode.

[0016] In some embodiments, the optical device includes a second substrate that is different from the first substrate and is spaced apart from the first substrate.

[0017] In some embodiments, the first substrate is spaced apart from the second substrate by at least 1 μm.

[0018] In some embodiments, the optical device includes a first optical polarizer.

[0019] In some embodiments, the optical device includes a second optical polarizer that is different from the first optical polarizer. The first optical polarizer is located adjacent to the first substrate and the second optical polarizer is located adjacent to the second substrate, or the first optical polarizer is located adjacent to the second substrate and the second optical polarizer is located adjacent to the first substrate.

[0020] In some embodiments, the ferroelectric liquid crystal includes one or more selected from the group consisting of: an aromatic mesogen having a 2,5-substituted 1,3-dioxane group, an aromatic mesogen having two or more oriented ester bonds and a nitro terminal group, and an aromatic ester mesogen having a nitrile terminal group.

[0021] In some embodiments, the ferroelectric liquid crystal includes one or more selected from the group consisting of: a rod-shaped material having a 1,3-dioxane group, 4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate, and

[0022]

[0023] In some embodiments, the chiral dopant includes one or more selected from the group consisting of: ZLI811, BDH1281, R5011, and S5011.

[0024] In some embodiments, the chiral dopant includes one or more selected from the group consisting of R2011, S2011, R1011, S1011, CB15, S811, and CBI15.

[0025] According to some embodiments, a head mounted display device includes a display panel and any optical device described herein, wherein the optical device is located adjacent to the display panel so that light passing through the optical device impinges on the display panel.

[0026] According to some embodiments, a method includes providing a first voltage gradient between a first electrode and a second electrode at a first time, the second electrode being different from and spaced apart from the first electrode. A medium including a ferroelectric liquid crystal and a chiral dopant is located at least adjacent to the first electrode. The method also includes providing a second voltage gradient between the first electrode and the second electrode at a second time mutually exclusive from the first time, the second voltage gradient being less than the first voltage gradient.

[0027] In some embodiments, the first voltage gradient is less than 0.2 V / μm.

[0028] In some embodiments, the first voltage gradient is greater than 0.018 V / μm and the second voltage is less than 0.018 V / μm.

[0029] The disclosed optical devices and methods can replace conventional optical devices and methods. The disclosed optical devices and methods can supplement conventional optical devices and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] For a better understanding of the various described embodiments, reference should be made to the following description of the embodiments in conjunction with the following drawings, wherein like reference numerals refer to corresponding parts throughout the drawings.

[0031] Figure 1 is a schematic diagram illustrating an electro-optical device according to some embodiments.

[0032] Figure 2 According to some embodiments, Figure 1 A cross-sectional view of the electro-optical device shown in FIG.

[0033] Figure 3A-3C is a schematic diagram showing the arrangement of liquid crystals according to some embodiments.

[0034] Figure 4 is a schematic diagram showing a transmittance curve according to some embodiments.

[0035] Figure 5 is a perspective view of a display device according to some embodiments.

[0036] Figure 6 is a block diagram of a system including a display device according to some embodiments.

[0037] Figure 7 is an isometric view of a display device according to some embodiments.

[0038] Unless otherwise indicated, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0039] As mentioned above, conventional electro-optical devices have limited switching speeds and dynamic ratios. The electro-optical devices described herein provide fast switching speeds and high dynamic ratios. In addition, the electro-optical devices described herein require low electric fields, which in turn reduces power consumption. In some configurations, switching speeds of about 1 millisecond can be achieved.

[0040] Reference will now be made to embodiments, examples of which are illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide an understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be implemented without these specific details. In other cases, well-known methods, procedures, components, circuits, and networks are not described in detail to avoid unnecessarily obscuring aspects of the embodiments.

[0041] Figure 1 is a schematic diagram illustrating an electro-optical device 100 according to some embodiments.

[0042] The electro-optic device 100 includes a first electrode 110. The first electrode 110 may be disposed adjacent to a medium (eg, as described below). Figure 2 The medium 210) described provides an electric field.

[0043] Figure 1 Also shown, in some embodiments, the electro-optic device 100 further includes a second electrode 130. In some embodiments, the second electrode 130 is distinct from the first electrode 110 and is spaced apart from the first electrode 110.

[0044] Figure 1 1. In some embodiments, the electro-optic device 100 further comprises a first substrate 140. In some embodiments, the first substrate 140 is located adjacent to the first electrode 110 (e.g., the first electrode 110 is located adjacent to the first substrate 140). In some embodiments, the first substrate 140 is also located adjacent to the second electrode 130 (e.g., the second electrode 130 is also located adjacent to the first substrate 140).

[0045] In some embodiments, the electro-optic device 100 is electrically coupled to a power source 160. The power source 160 can provide a voltage or current to the electro-optic device 100 (e.g., across or between the first electrode 110 and the second electrode 130). For example, in some embodiments, the first electrode 110 and the second electrode 130 are electrically coupled to the power source 160. In some embodiments, the electro-optic device 100 includes the power source 160. In some embodiments, the power source 160 is not part of the electro-optic device 100.

[0046] like Figure 1 As shown, in some embodiments, the power supply 160 includes one or more voltage sources 162 and 164. In some embodiments, the power supply 160 includes one or more current sources 166. In some embodiments, the power supply 160 includes one or more voltage sources 162 and 164 and one or more current sources 166. In some embodiments, the power supply 160 includes one or more voltage sources 162 and 164 without one or more current sources 166. In some embodiments, the power supply 160 includes one or more current sources 166 without one or more voltage sources 162 and 164.

[0047] In some embodiments, power source 160 includes a power storage device (eg, a battery or a capacitor).

[0048] In some embodiments, electro-optic device 100 also includes an electrostatic source (eg, an electrostatic material). This allows the electric field to be generated without using an electrical power source.

[0049] like Figure 1 As shown, in some embodiments, one or more current sources 166 are electrically connected in parallel to one or more impedances 168 (eg, resistors). In some embodiments, one or more current sources are electrically connected in series.

[0050] like Figure 1 As shown, in some embodiments, one or more voltage sources 162 and 164 are electrically connected in parallel (e.g., voltage source 162 is electrically connected in parallel to voltage source 164). In some embodiments, one or more voltage sources 162 and 164 include a DC voltage source. In some embodiments, one or more voltage sources 162 and 164 include an AC voltage source (or a dynamic voltage source that provides voltage in a non-sinusoidal mode). In some embodiments, one or more voltage sources 162 and 164 include both a DC voltage source and an AC voltage source (or a dynamic voltage source).

[0051] like Figure 1As shown, in some embodiments, the electro-optic device 100 includes a second substrate 150. In some embodiments, the second substrate 150 is different from the first substrate 140 and is spaced apart from the first substrate 140. This allows the first substrate 140 and the second substrate 150 to define a cavity between the first substrate 140 and the second substrate. In some configurations, the electro-optic device 100 includes a medium (e.g., reference Figure 2 described medium 210).

[0052] Figure 1 It also shows the Figure 2 The plane of the cross-sectional view shown in .

[0053] Figure 2 According to some embodiments, Figure 1 A cross-sectional view of the electro-optical device 100 is shown in FIG. Figure 1 , Figure 2 A first electrode 110 , a second electrode 130 , a first substrate 140 , and a second substrate 150 are also shown. Figure 2 It is also shown that, in some embodiments, the electro-optic device 100 further includes one or more side walls 220 and 230 .

[0054] Figure 2 The first electrode 110 and the second electrode 130 are shown separated by a distance 250 . Figure 2 The first substrate 140 and the second substrate 150 are also shown to be spaced apart a distance 260 .

[0055] Figure 2 Also shown is a medium 210 located adjacent to the first electrode 110 (e.g., in contact with the first electrode 110, or in proximity to the first electrode 110 even if not in direct contact with the first electrode 110). Figure 2 As shown, the medium 210 may also be located adjacent to the second electrode 130 (e.g., in contact with both the first electrode 110 and the second electrode 130, or close to the first electrode 110 and the second electrode 130 while in direct contact with one or both of the first electrode 110 and the second electrode 130). Figure 2 As shown, the medium 210 is located between the first substrate 140 and the second substrate 150. In some embodiments, as Figure 2 As shown, the medium 210 is located in a cavity defined by the first substrate 140 , the second substrate 150 , and the sidewalls 220 and 230 .

[0056] The medium 210 includes ferroelectric liquid crystal 212 .

[0057] In some embodiments, the ferroelectric liquid crystal includes one or more selected from the group consisting of: aromatic mesogens having 2,5-substituted 1,3-dioxane groups (DIO analogs), aromatic mesogens having two or more oriented ester bonds and nitro terminal groups (RM734 analogs), and aromatic ester mesogens having nitrile terminal groups.

[0058] In some embodiments, the ferroelectric liquid crystal comprises:

[0059]

[0060] In some embodiments, the ferroelectric liquid crystal comprises:

[0061]

[0062] In some embodiments, the ferroelectric liquid crystal includes one or more selected from the group consisting of: (i) a rod-shaped material having a 1,3-dioxane group, (ii) 4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate, and (iii)

[0063]

[0064] In some embodiments, the chiral dopant 214 includes one or more selected from the group consisting of: ZLI811, BDH1281, R5011, and S5011. In some embodiments, ZLI811 has a structure represented by:

[0065]

[0066] In some embodiments, BDH1281 has the structure represented by:

[0067]

[0068] In some embodiments, R5011 has a structure represented by:

[0069]

[0070] In some embodiments, S5011 has a structure represented by:

[0071]

[0072] In some embodiments, the chiral dopant 214 includes one or more selected from the group consisting of: R2011 ([4(R)-[trans(trans)]]-1,3-difluoro-2-[(1-methylheptyl)oxy]-5-(4'-propyl[1,1'-bicyclohexyl]-4-Yl)benzene), S2011 ([4(S)-[trans(trans)]]-1,3-difluoro-2-[(1-methylheptyl)oxy]-5-(4'-propyl[1,1'-bicyclohexyl]-4-Yl)benzene). 1-[(S)-2-methylbutyl]biphenyl-4-carbonitrile), R811 ((R)-2-octyl 4-[4-(hexyloxy)benzoyloxy]benzoate), and S811 (S-(+)-2-octyl 4-(4-hexyloxybenzoyloxy)benzoate).

[0073] In some embodiments, the chiral dopant 214 includes one or more selected from the group consisting of:

[0074]

[0075]

[0076] In some embodiments, chiral dopant 214 includes any chiral dopant described herein. In some embodiments, chiral dopant 214 can include any other chiral dopant.

[0077] In some embodiments, the medium 210 includes one or more colorants. In some configurations, the one or more colorants can provide a default color (e.g., a default absorption profile) for the medium 210. For example, the one or more colorants can add a tint to the electro-optical device.

[0078] In some embodiments, medium 210 may include other components (eg, solvents, etc.).

[0079] In some embodiments, the electro-optical device further includes one or more optical components (e.g., lenses, optical filters, optical polarizers, etc.). Figure 2 As shown, in some embodiments, the electro-optical device includes a first optical polarizer 260 and a second optical polarizer 270. Figure 2In some embodiments, the electro-optic device includes the first optical polarizer 260 without the second optical polarizer 270. In some embodiments, the electro-optic device includes the second optical polarizer 270 without the first optical polarizer 260. In some embodiments, the first optical polarizer 260 is in contact with the first substrate 140. In some embodiments, the first optical polarizer 260 is not in direct contact with the first substrate 140 (for example, one or more intermediate components may be located between the first optical polarizer 260 and the first substrate 140). In some embodiments, the second optical polarizer 270 is in contact with the second substrate 150. In some embodiments, the second optical polarizer 270 is not in direct contact with the second substrate 150 (for example, one or more intermediate components may be located between the second optical polarizer 270 and the second substrate 150). In some embodiments, the first optical polarizer 260 and the second optical polarizer 270 are located away from the medium 210 (for example, the first optical polarizer 260 and the second optical polarizer 270 are not in direct contact with the medium 210). In some embodiments, at least one of the first optical polarizer 260 or the second optical polarizer 270 is positioned to be in direct contact with the medium 210.

[0080] Figure 3A-3C is a schematic diagram showing the arrangement of liquid crystals according to some embodiments.

[0081] Figure 3A 2 shows the arrangement of the liquid crystal 212 when a first voltage V1 (eg, 0 V) ​​is applied across the electrodes 110 and 130. Figure 3A In the embodiment, liquid crystal 212 is arranged in a spiral shape with a pitch 214.

[0082] Figure 3B 2 shows the arrangement of liquid crystal 212 when a second voltage V2 greater than V1 is applied across electrodes 110 and 130. Figure 3B In FIG. 2 , liquid crystal 212 is arranged in a spiral having a pitch 216 that is different from (eg, greater than) pitch 214 .

[0083] Figure 3C 2 shows the arrangement of liquid crystal 212 when a third voltage V3 greater than V2 is applied across electrodes 110 and 130. Figure 3C In the embodiment, the liquid crystals 212 are arranged facing the same lateral direction.

[0084] Figures 3A-3CAlso shown are different effects of different arrangements of liquid crystals on light passing through the electro-optical device. For example, different arrangements of liquid crystals can affect the intensity or polarization of light passing through the electro-optical device. For example, in response to light 310 provided to the electro-optical device, the light output from the electro-optical device can have different intensities and / or polarizations depending on the arrangement of the liquid crystals, which depends on the voltage applied to electrodes 110 and 130. For example, light 320-2 can have a different intensity and / or polarization than light 320-1. For example, light 320-3 can have a different intensity and / or polarization than light 320-2 or light 320-1.

[0085] Figure 4 4 is a schematic diagram illustrating a transmittance curve according to some embodiments. By changing the voltage applied across electrodes 110 and 130, the transmittance of the electro-optic device is changed. For example, when the voltage applied between electrodes 110 and 130 increases, in some configurations, the transmittance decreases from transmittance curve 410 to transmittance curve 430, and then decreases to transmittance curve 420. In some embodiments, transmittance curve 410 can represent the transmittance curve of the electro-optic device when voltage V1 is applied, such as Figure 3A Transmittance curve 430 may represent the transmittance curve of the electro-optical device when a voltage V2 is applied, such as Figure 3B and transmittance curve 420 may represent the transmittance curve of the electro-optical device when a voltage V3 is applied, such as Figure 3C Although transmittance curves can have slopes and other features, they do not have Figure 4 , so as not to obscure other aspects of the operation of the electro-optical device. Figure 4 In FIG. 4 , the transmittance curve 410 indicates a transmittance greater than 90%. Figure 4 , the transmittance curve 420 indicates a transmittance of less than 15%.

[0086] In some embodiments, the electro-optical device (e.g., 100) can be used in a display device such as a head-mounted display device. In some embodiments, the electro-optical device (e.g., 100) can be implemented as a multifunctional optical component in a near-eye display for augmented reality (AR), virtual reality (VR), and / or mixed reality (MR). For example, the disclosed optical element or device can be implemented as an optical dimming element (e.g., a variable intensity filter), etc., which can significantly reduce weight and size and enhance the optical performance of the head-mounted display device. Reference Figure 5-Figure 7 Exemplary embodiments of head mounted display devices implementing electro-optical devices (eg, 100) are described.

[0087] Figure 5500 according to some embodiments. In some embodiments, the display device 500 is configured to be worn on the user's head (e.g., in the form of glasses or eyeglasses, such as Figure 5 ) or included as part of a helmet to be worn by a user. When the display device 500 is configured to be worn on the user's head or included as part of a helmet, the display device 500 is referred to as a head-mounted display. Alternatively, the display device 500 is configured to be placed near one or both eyes of the user at a fixed position, rather than being worn on the head (e.g., the display device 500 is installed in a vehicle such as a car or airplane to be placed in front of one or both eyes of the user). Figure 5 As shown, display device 500 includes display 510. Display 510 is configured to present visual content (e.g., augmented reality content, virtual reality content, mixed reality content, or any combination thereof) to a user.

[0088] In some embodiments, the display device 500 includes a reference Figure 6 In some embodiments, the display device 500 includes one or more components described herein. Figure 6 Additional components not shown.

[0089] Figure 6 is a block diagram of a system 600 according to some embodiments. Figure 6 The system 600 shown includes display devices 605 each coupled to a console 610 (which is Figure 5 The display device 500 shown in FIG. 6 corresponds to the display device 500), the imaging device 635 and the input interface 640. Figure 6 An embodiment of a system 600 including a display device 605, an imaging device 635 and an input interface 640 is shown, but in other embodiments, any number of these components may be included in the system 600. For example, there may be multiple display devices 605, each display device having an associated input interface 640 and monitored by one or more imaging devices 635, each display device 605, an input interface 640 and an imaging device 635 communicating with a console 610. In an alternative configuration, the system 600 may include different and / or additional components. For example, in some embodiments, the console 610 is connected to the system 600 via a network (e.g., the Internet or a wireless network), or is independent (self-contained) (e.g., physically located in the display device 605) as a part of the display device 605. In some embodiments, the display device 605 is used to create a mixed reality by adding a view of a real environment. Therefore, the display device 605 and the system 600 described herein can transmit augmented reality, virtual reality and mixed reality.

[0090] In some embodiments, such as Figure 5 As shown, display device 605 is a head-mounted display that presents media to the user. The embodiment of the media presented by display device 605 includes one or more images, videos, audio, or some combination thereof. In some embodiments, audio is presented via an external device (e.g., speaker and / or earphone), which receives audio information from display device 605, console 610, or both and presents audio data based on the audio information. In some embodiments, display device 605 immerses the user in an enhanced environment.

[0091] In some embodiments, the display device 605 is also used as an augmented reality (AR) headset. In these embodiments, the display device 605 uses computer-generated elements (e.g., images, videos, sounds, etc.) to enhance the view of the physical, real-world environment. In addition, in some embodiments, the display device 605 can cycle between different types of operations. Therefore, based on instructions from the application engine 655, the display device 605 operates as a virtual reality (VR) device, an augmented reality (AR) device, as glasses, or some combination thereof (e.g., glasses without optical correction, glasses with optical correction for the user, sunglasses, or some combination thereof).

[0092] The display device 605 includes an electronic display 615, one or more processors 616, an eye tracking module 617, an adjustment module 618, one or more positioners 620, one or more position sensors 625, one or more position cameras 622, a memory 628, an inertial measurement unit (IMU) 630, one or more optical elements 660, or a subset or superset thereof (e.g., a display device 605 having an electronic display 615, one or more processors 616, and a memory 628 without any other listed components). Some embodiments of the display device 605 have modules different from those described herein. Similarly, functionality can be distributed among modules in a manner different from that described herein.

[0093] One or more processors 616 (e.g., processing units or processing cores) execute instructions stored in memory 628. Memory 628 includes high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices; and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. Memory 628 or alternatively non-volatile memory devices within memory 628 include non-transitory computer-readable storage media. In some embodiments, memory 628 or a computer-readable storage medium of memory 628 stores programs, modules, and data structures, and / or instructions for displaying one or more images on electronic display 615.

[0094] The electronic display 615 displays images to the user based on data received from the console 610 and / or the processor 616. In various embodiments, the electronic display 615 can include a single adjustable display element or multiple adjustable display elements (e.g., a display for each eye of the user). In some embodiments, the electronic display 615 is configured to display images to the user by projecting the images onto one or more optical elements 660.

[0095] In some embodiments, the display element includes one or more light-emitting devices and a corresponding array of spatial light modulators. The spatial light modulator is an array of electro-optical pixels, an array of optoelectronic pixels, an array of some other devices that dynamically adjust the amount of light transmitted by each device, or an array of some combination thereof. These pixels are placed behind one or more lenses. In some embodiments, the spatial light modulator is an array of pixels based on liquid crystal in an LCD (Liquid Crystal Display). Embodiments of light-emitting devices include: organic light-emitting diodes, active matrix organic light-emitting diodes, light-emitting diodes, some type of device that can be placed in a flexible display, or some combination thereof. The light-emitting device includes a device that can generate visible light (e.g., red, green, blue, etc.) for image generation. The spatial light modulator is configured to selectively attenuate a single light-emitting device, a group of light-emitting devices, or some combination thereof. Alternatively, when the light-emitting device is configured to selectively attenuate a single emission device and / or a group of light-emitting devices, the display element includes an array of such light-emitting devices without a separate emission intensity array. In some embodiments, the electronic display 615 projects an image onto one or more optical elements 660, which reflect at least a portion of the light toward the user's eyes.

[0096] One or more lenses direct light from the array of light emitting devices (optionally via an emission intensity array) to locations within each eyebox and ultimately to the back of the user's retina. The eyebox is the area occupied by the user's eye located near the display device 605 (e.g., the user wearing the display device 605) for viewing images from the display device 605. In some cases, the eyebox is represented as a 10 mm x 10 mm square. In some embodiments, one or more lenses include one or more coatings, such as an anti-reflective coating.

[0097] In some embodiments, the display element includes an infrared (IR) detector array that detects IR light retro-reflected from the retina of the viewing user, from the surface of the cornea, the lens of the eye, or some combination thereof. The IR detector array includes an IR sensor or multiple IR sensors, each IR sensor corresponding to a different position of the pupil of the viewing user's eye. In alternative embodiments, other eye tracking systems may also be used. As used herein, IR refers to light with a wavelength range of 700nm to 1mm, including near infrared (NIR) in the range of 750nm to 1500nm.

[0098] The eye tracking module 617 determines the position of each pupil of the user's eyes. In some embodiments, the eye tracking module 617 instructs the electronic display 615 to illuminate the eye sockets with IR light (e.g., via an IR emitting device in the display element).

[0099] Part of the emitted IR light will pass through the pupil of the viewing user and reflect back from the retina toward the IR detector array, which is used to determine the pupil position. Alternatively, reflections leaving the surface of the eye are also used to determine the position of the pupil. The IR detector array scans the retroreflection and identifies which infrared emitting devices are active when the retroreflection is detected. The eye tracking module 617 can use the tracking lookup table and the identified IR emitting devices to determine the pupil position of each eye. The tracking lookup table maps the received signal on the IR detector array to the position in each moving eye socket (corresponding to the pupil position). In some embodiments, the tracking lookup table is generated via a calibration procedure (for example, the user looks at various known reference points in the image, and the eye tracking module 617 maps the position of the user's pupil when looking at the reference point to the corresponding signal received on the IR tracking array). As described above, in some embodiments, the system 600 can use other eye tracking systems besides the embedded IR eye tracking system described herein.

[0100] The adjustment module 618 generates an image frame based on the determined pupil position. In some embodiments, this sends discrete images to a display that tiles the sub-images together so that a coherent stitched image will appear on the back of the retina. The adjustment module 618 adjusts the output (i.e., the generated image frame) of the electronic display 615 based on the detected pupil position. The adjustment module 618 instructs the portion of the electronic display 615 to pass the image light to the determined pupil position. In some embodiments, the adjustment module 618 also instructs the electronic display not to pass the image light to a position other than the determined pupil position. The adjustment module 618 can, for example, prevent and / or stop the light emitting device whose image light falls outside the determined pupil position, allow other light emitting devices to emit image light falling within the determined pupil position, translate and / or rotate one or more display elements, dynamically adjust the curvature and / or refractive power of one or more active lenses in the lens (e.g., microlens) array, or some combination thereof.

[0101] The optional locators 620 are objects located at specific locations on the display device 605 relative to each other and relative to specific reference points on the display device 605. The locators 620 can be light emitting diodes (LEDs), corner cube reflectors, reflective markers, light sources of a type that contrast with the environment in which the display device 605 operates, or some combination thereof. In embodiments where the locators 620 are active (i.e., LEDs or other types of light emitting devices), the locators 620 can emit light in the visible band (e.g., about 500 nm to 750 nm), the infrared band (e.g., about 750 nm to 1 mm), the ultraviolet band (about 100 nm to 500 nm), some other portion of the electromagnetic spectrum, or some combination thereof.

[0102] In some embodiments, the locator 620 is located below an outer surface of the display device 605 that is transparent to the wavelength of light emitted or reflected by the locator 620, or is thin enough not to substantially attenuate the wavelength of light emitted or reflected by the locator 620. Additionally, in some embodiments, the outer surface or other portion of the display device 605 is opaque in the visible band of wavelengths of light. Thus, the locator 620 can emit light in the IR band below an outer surface that is transparent in the IR band but opaque in the visible band.

[0103] The IMU 630 is an electronic device that generates calibration data based on measurement signals received from one or more position sensors 625. The position sensor 625 generates one or more measurement signals in response to the movement of the display device 605. Embodiments of the position sensor 625 include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor that detects movement, a type of sensor used for error correction of the IMU 630, or some combination thereof. The position sensor 625 can be located outside the IMU 630, inside the IMU 630, or some combination thereof.

[0104] Based on one or more measurement signals from one or more position sensors 625, the IMU 630 generates first calibration data indicating an estimated position of the display device 605 relative to the initial position of the display device 605. For example, the position sensor 625 includes multiple accelerometers for measuring translational motion (forward / backward, up / down, left / right) and multiple gyroscopes for measuring rotational motion (e.g., pitch, sway, flip). In some embodiments, the IMU 630 samples the measurement signals quickly and calculates the estimated position of the display device 605 from the sampled data. For example, the IMU 630 integrates the measurement signals received from the accelerometers over time to estimate the velocity vector, and integrates the velocity vector over time to determine the estimated position of a reference point on the display device 605. Alternatively, the IMU 630 provides the sampled measurement signals to the console 610, and the console determines the first calibration data. The reference point is a point that can be used to describe the position of the display device 605. Although a reference point may generally be defined as a point in space; however, in practice, the reference point is defined as a point within the display device 605 (eg, the center of the IMU 630).

[0105] In some embodiments, the IMU 630 receives one or more calibration parameters from the console 610. As discussed further below, the one or more calibration parameters are used to maintain tracking of the display device 605. Based on the received calibration parameters, the IMU 630 can adjust one or more IMU parameters (e.g., sampling rate). In some embodiments, certain calibration parameters cause the IMU 630 to update the initial position of the reference point so that it corresponds to the next calibration position of the reference point. Updating the initial position of the reference point to the next calibration position of the reference point helps to reduce the cumulative error associated with the determined estimated position. The cumulative error (also known as drift error) causes the estimated position of the reference point to "drift" away from the actual position of the reference point over time.

[0106] The imaging device 635 generates calibration data based on the calibration parameters received from the console 610. The calibration data includes one or more images showing the observed position of the locator 620, and the one or more images can be detected by the imaging device 635. In some embodiments, the imaging device 635 includes one or more still cameras, one or more video cameras, any other device capable of capturing images including one or more locators 620, or some combination thereof. In addition, the imaging device 635 can include one or more filters (e.g., for increasing the signal-to-noise ratio). The imaging device 635 is configured to optionally detect light emitted or reflected from the locator 620 in the field of view of the imaging device 635. In embodiments where the positioners 620 include passive elements (e.g., retroreflectors), the imaging device 635 may include a light source that illuminates some or all of the positioners 620, which retroreflect light toward the light source in the imaging device 635. The second calibration data is communicated from the imaging device 635 to the console 610, and the imaging device 635 receives one or more calibration parameters from the console 610 to adjust one or more imaging parameters (e.g., focal length, focus, frame rate, ISO, sensor temperature, shutter speed, aperture, etc.).

[0107] In some embodiments, the display device 605 optionally includes one or more optical elements 660 (e.g., lenses, reflectors, gratings, etc.). In some embodiments, the electronic display device 605 includes a single optical element 660 or multiple optical elements 660 (e.g., an optical element 660 for each eye of the user). In some embodiments, the electronic display 615 projects a computer-generated image onto one or more optical elements 660 (such as a reflective element), which in turn reflects the image toward one or more eyes of the user. The computer-generated image includes a still image, an animated image, and / or a combination thereof. The computer-generated image includes an object that appears to be a two-dimensional and / or three-dimensional object. In some embodiments, one or more optical elements 660 are partially transparent (e.g., one or more optical elements 660 have a transmittance of at least 15%, 20%, 25%, 30%, 35%, 50%, 55%, or 50%), which allows the transmission of ambient light. In such an embodiment, the computer-generated image projected by the electronic display 615 is superimposed with the transmitted ambient light (eg, the transmitted ambient image) to provide an augmented reality image.

[0108] In some embodiments, one or more optical elements 660 or a subset thereof are positioned to modify light (e.g., ambient light) transmitted to the electronic display 615. For example, one or more optical elements 660 may include an optical dimmer to selectively reduce the intensity of light passing through the optical dimmer. In some embodiments, the optical element 660 includes the optical elements described above with reference to Figure 1-Figure 2 , Figure 3A-3C and Figure 4 An electro-optical device (eg, 100) is described.

[0109] The input interface 640 is a device that allows a user to send an action request to the console 610. An action request is a request to perform a specific operation. For example, an action request can be to start or end an application, or to perform a specific action within an application. The input interface 640 may include one or more input devices. Exemplary input devices include: a keyboard, a mouse, a game controller, data from brain signals, data from other parts of the human body, or any other suitable device for receiving an action request and transmitting the received action request to the console 610. The action request received by the input interface 640 is transmitted to the console 610, and the console 610 performs an action corresponding to the action request. In some embodiments, the input interface 640 may provide tactile feedback to the user according to the instructions received from the console 610. For example, tactile feedback is provided when an action request is received, or the console 610 transmits an instruction to the input interface 640 so that the input interface 640 generates tactile feedback when the console 610 performs an action.

[0110] The console 610 provides media to the display device 605 for presentation to the user based on information received from one or more of the imaging device 635, the display device 605, and the input interface 640. Figure 6 In the illustrated embodiment, the console 610 includes an application store 645, a tracking module 650, and an application engine 655. Some embodiments of the console 610 have Figure 6 Similarly, the functionality described further herein may be distributed among the components of console 610 in a manner different from that described herein.

[0111] When an application store 645 is included in the console 610, the application store 645 stores one or more applications executed by the console 610. An application is a set of instructions that, when executed by a processor, are used to generate content presented to a user. The content generated by the processor based on the application can be responsive to input received from the user through movement of the display device 605 or input interface 640. Examples of applications include: gaming applications, conferencing applications, video playback applications, or other suitable applications.

[0112] When the tracking module 650 is included in the console 610, the tracking module 650 uses one or more calibration parameters to calibrate the system 600, and can adjust one or more calibration parameters to reduce errors in determining the position of the display device 605. For example, the tracking module 650 adjusts the focus of the imaging device 635 to obtain a more accurate position of the localizers observed on the display device 605. In addition, the calibration performed by the tracking module 650 also takes into account information received from the IMU 630. In addition, if tracking of the display device 605 is lost (e.g., the imaging device 635 loses sight of at least a threshold number of the localizers 620), the tracking module 650 recalibrates part or all of the system 600.

[0113] In some embodiments, the tracking module 650 uses the second calibration data from the imaging device 635 to track the movement of the display device 605. For example, the tracking module 650 uses the second calibration data and the observation locator of the model of the display device 605 to determine the position of the reference point of the display device 605. In some embodiments, the tracking module 650 also uses the position information from the first calibration data to determine the position of the reference point of the display device 605. In addition, in some embodiments, the tracking module 650 can use the first calibration data, the second calibration data, or some combination thereof to predict the future position of the display device 605. The tracking module 650 provides the estimated or predicted future position of the display device 605 to the application engine 655.

[0114] The application engine 655 executes applications within the system 600 and receives position information, acceleration information, velocity information, predicted future position, or some combination thereof of the display device 605 from the tracking module 650. Based on the received information, the application engine 655 determines the content to be provided to the display device 605 for presentation to the user. For example, if the received information indicates that the user has looked to the left, the application engine 655 generates content for the display device 605 that reflects the user's movement in the augmented environment. In addition, the application engine 655 performs an action within an application executed on the console 610 in response to an action request received from the input interface 640, and provides feedback to the user that the action has been performed. The feedback provided can be visual or auditory feedback through the display device 605, or tactile feedback through the input interface 640.

[0115] Figure 7700 is an isometric view of a display device 700 according to some embodiments. In some other embodiments, the display device 700 is part of some other electronic display (e.g., a digital microscope, a head-mounted display device, etc.). In some embodiments, the display device 700 includes a light emitting device 710 (e.g., an array of light emitting devices) and an optical assembly 730, which may include one or more lenses and / or other optical components. In some embodiments, the display device 700 also includes an IR detector array.

[0116] Light emitting device 710 emits image light and optional IR light to the viewing user. Light emitting device 710 includes one or more light emitting components that emit light in visible light (and optionally includes components that emit light in IR). Light emitting device 710 may include, for example, an LED array, a micro LED array, an organic LED array (OLED), a superluminescent LED array (SLED), or some combination thereof.

[0117] In some embodiments, the light emitting device 710 includes an emission intensity array (e.g., a spatial light modulator) configured to selectively attenuate light emitted from the light emitting device 710. In some embodiments, the emission intensity array is composed of a plurality of liquid crystal cells or pixels, a light emitting device group, or some combination thereof. Each liquid crystal cell (or in some embodiments, a liquid crystal cell group) is addressable to have a specific attenuation level. For example, at a given time, some liquid crystal cells can be set to no attenuation, while other liquid crystal cells can be set to maximum attenuation. In this way, the emission intensity array is capable of providing image light and / or controlling which portion of the image light is transmitted. In some embodiments, the display device 700 uses an emission intensity array to provide image light to the position of the pupil 750 of the user's eye 740 and minimize the amount of image light provided to other areas in the eye movement frame. In some embodiments, the display device 700 includes an electro-optical device that operates as a display resolution enhancement component or is optically coupled to the electro-optical device. In some embodiments, the display device 700 is an augmented reality display device. In such an embodiment, the display device 700 includes or is optically coupled to an electro-optical device that operates as a waveguide-based combiner or as a polarization-selective reflector.

[0118] In some embodiments, the display device 700 includes one or more lenses. The one or more lenses receive modified image light (e.g., attenuated light) from the light emitting device 710 and direct the modified image light to the location of the pupil 750. The optical assembly may include additional optical components, such as filters, reflectors, etc.

[0119] In some embodiments, the optical assembly 730 includes the Figure 1-Figure 2 , Figure 3A-3C and Figure 4 The electro-optic device (e.g., 100) described herein. The electro-optic device 100 has a variable transmittance (e.g., has a first transmittance curve at a first time and has a second transmittance curve different from the first transmittance curve at a second time, the second time being mutually exclusive with the first time). The electro-optic device 100 conditionally reduces the intensity of light passing through the electro-optic device 100. In some embodiments, the electro-optic device 100 has only a single window that has a uniform transmittance across the window at all times (e.g., the electro-optic device 100 operates as a single variable intensity filter). In some embodiments, as Figure 7 As shown, the electro-optic device 100 has a plurality of regions, wherein each region may have a transmittance that is independent of the transmittances of other regions. For example, the electro-optic device 100 may include Figure 1 and Figure 2 An array of structures is shown.

[0120] The optional IR detector array detects IR light retroreflected from the retina of eye 740, the cornea of ​​eye 740, the lens of eye 740, or some combination thereof. The IR detector array includes a single IR sensor or multiple IR sensitive detectors (e.g., photodiodes). In some embodiments, the IR detector array is separate from the light emitting device 710. In some embodiments, the IR detector array is integrated into the light emitting device 710.

[0121] In some embodiments, a light emitting device 710 including an emission intensity array constitutes a display element. Alternatively, the display element includes a light emitting device 710 without an emission intensity array (e.g., when the light emitting device 710 includes individually adjustable pixels). In some embodiments, the display element additionally includes an IR array. In some embodiments, in response to the determined position of the pupil 750, the display element adjusts the emitted image light so that the light output by the display element is refracted by one or more lenses toward the determined position of the pupil 750 (rather than toward other positions in the orbit).

[0122] In some embodiments, display device 700 includes one or more broadband light sources (eg, one or more white light LEDs) coupled with a plurality of color filters in addition to or in place of light emitting device 710 .

[0123] Based on these principles, we now turn to some implementation plans.

[0124] According to some embodiments, an optical device (e.g., electro-optical device 100) includes a first electrode (e.g., electrode 110) and a medium (e.g., medium 210) including a ferroelectric liquid crystal (e.g., liquid crystal 212) and a chiral dopant (e.g., chiral dopant 214). The medium is located adjacent to the first electrode.

[0125] In some embodiments, the first electrode is transparent. For example, the first electrode can be made of an optically transparent conductive material, such as indium-tin-oxide (ITO). In some embodiments, the first electrode is opaque.

[0126] In some embodiments, the optical device includes a second electrode (eg, second electrode 130 ) that is different from the first electrode and spaced apart from the first electrode.

[0127] In some embodiments, the second electrode is transparent. For example, the first electrode can be made of an optically transparent conductive material, such as indium tin oxide (ITO). In some embodiments, the second electrode is opaque.

[0128] In some embodiments, the first electrode and the second electrode extend along a common plane. Figure 2 As shown, electrodes 110 and 130 are on a common plane.

[0129] In some embodiments, the first electrode extends along a first plane, and the second electrode extends along a second plane parallel to and offset from the first plane. For example, the first electrode and the second electrode may be parallel to each other, but may be located at different heights on the substrate.

[0130] In-plane electric field switching (IPS) facilitates the implementation of electro-optical devices as arrays. For example, an optical system may include an array of pixels, where each pixel includes the electro-optical device described herein. This configuration allows the optical system to control each pixel individually, so that each pixel independently transmits or blocks light.

[0131] In some embodiments, the first electrode is spaced at least 20 μm from the second electrode (e.g., distance 250 is at least 20 μm). In some embodiments, distance 250 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000 μm, or in intervals between any two of the above numbers.

[0132] In some embodiments, the optical device includes a first substrate (eg, substrate 14) positioned adjacent to the first electrode.

[0133] In some embodiments, the optical device includes a second substrate (eg, substrate 150 ) that is different from and spaced apart from the first substrate.

[0134] In some embodiments, the first substrate is spaced apart from the second substrate by at least 1 μm (e.g., distance 260 is at least 1 μm). In some embodiments, distance 260 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000 μm, or in intervals between any two of the above numbers.

[0135] In some embodiments, the optical device includes a first optical polarizer (eg, optical polarizer 260).

[0136] In some embodiments, the optical device includes a second optical polarizer (e.g., optical polarizer 270) that is different from the first optical polarizer. The first optical polarizer is located adjacent to the first substrate and the second optical polarizer is located adjacent to the second substrate, or the first optical polarizer is located adjacent to the second substrate and the second optical polarizer is located adjacent to the first substrate.

[0137] In some embodiments, the ferroelectric liquid crystal includes one or more selected from the group consisting of: an aromatic mesogen having a 2,5-substituted 1,3-dioxane group, an aromatic mesogen having two or more oriented ester bonds and a nitro terminal group, and an aromatic ester mesogen having a nitrile terminal group.

[0138] In some embodiments, the ferroelectric liquid crystal includes one or more selected from the group consisting of: a rod-shaped material having a 1,3-dioxane group, 4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate, and

[0139]

[0140] In some embodiments, the chiral dopant includes one or more selected from the group consisting of: ZLI811, BDH1281, R5011, and S5011.

[0141] In some embodiments, the chiral dopant includes one or more selected from the group consisting of R2011, S2011, R1011, S1011, CB15, S811, and CBI15.

[0142] According to some embodiments, a head-mounted display device (e.g., display device 500 or 700) includes a display panel (e.g., display panel 510 or light emitting device 710) and any optical device described herein (e.g., optical device 100). The optical device is located adjacent to the display panel so that light passing through the optical device is irradiated on the display panel (e.g., Figure 7 ). In some embodiments, the optical device modifies the intensity of light passing through the optical device.

[0143] According to some embodiments, the method includes providing a first voltage gradient between the first electrode and the second electrode at a first time (e.g., a voltage gradient corresponding to the first voltage applied across electrodes 110 and 130, such as Figure 3C The method further includes providing a second voltage gradient (e.g., a voltage gradient corresponding to the second voltage applied across electrodes 110 and 130, such as V3) between the first electrode and the second electrode at a second time mutually exclusive from the first time, which is less than the first voltage gradient. Figure 3A V1 in the .

[0144] In some configurations, when no electric field is applied (or a low electric field is applied), the optical device has a high optical transmittance (e.g., 410), and when a sufficient electric field is applied (or a high electric field is applied), the optical device has a low optical transmittance (e.g., 420). For example, the optical device may include an electrostatic source (e.g., an electrostatic material) to arrange the liquid crystal in a state with low light transmittance. Alternatively, the optical device may include a power storage (e.g., a battery or a capacitor) to generate an electric field to place the optical device in a state with low light transmittance.

[0145] In some other configurations, the optical device may have a low optical transmittance when no electric field is applied (or a low electric field is applied), and may have a high optical transmittance when a sufficient electric field is applied (or a high electric field is applied). For example, the optical device may include an electrostatic source (e.g., an electrostatic material) to arrange the liquid crystal in a state with high light transmittance. Alternatively, the optical device may include a power storage (e.g., a battery or a capacitor) to generate an electric field to place the optical device in a state with high light transmittance.

[0146] In some embodiments, the pitch of the liquid crystal (e.g., 214) is selected (e.g., by selecting a chiral dopant) to correspond to a non-visible wavelength (e.g., ultraviolet or infrared). In some embodiments, the chiral dopant is selected to provide a specific pitch for the liquid crystal (e.g., when no electric field is provided).

[0147] In some embodiments, the first voltage gradient is less than 0.2V / μm. In some embodiments, the first voltage gradient is less than 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04 or 0.03V / μM or in the interval between any two of the above numbers. In some embodiments, a first voltage gradient greater than 0.2V / μM can be used.

[0148] In some embodiments, the first voltage gradient is greater than 0.018 V / μm and the second voltage gradient is less than 0.018 V / μm. In some embodiments, the first voltage gradient is greater than 0.01 V / μm and the second voltage gradient is less than 0.01 V / μm. In some embodiments, the first voltage gradient is greater than 0.1 V / μm and the second voltage gradient is less than 0.1 V / μm.

[0149] In some embodiments, the electro-optic device operates at elevated temperatures (eg, 100° C., 122° C., etc.) or at room temperature (eg, 20° C.).

[0150] Although the head mounted display is shown as an apparatus including the described electro-optical device, such electro-optical devices can be used in other systems, devices and apparatuses. For example, the electro-optical devices described herein can be used as smart windows (for buildings or vehicles) or switchable blinds.

[0151] The terms "and" and "or" as used herein may include a variety of meanings, which are also expected to depend at least in part on the context in which the terms are used. Typically, if used in a related list, such as A, B, or C, "or" means A, B, and C (here in an inclusive sense) as well as A, B, or C (here in an exclusive sense). In addition, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in the singular, or may be used to describe a certain combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example, and the subject matter claimed is not limited to such an example. In addition, if used in a related list, such as A, B, or C, the term "at least one" may be interpreted to mean any combination of A, B, and / or C, such as A, AB, AC, BC, AA, ABC, AAB, AABBCCC, etc.

[0152] The methods, systems, and devices discussed above are examples. Various embodiments may appropriately omit, replace, or add various programs or components. For example, in alternative configurations, the described methods may be performed in an order different from that described, and / or various stages may be added, omitted, and / or combined. In addition, the features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. In addition, technology is developing, and therefore, many elements are embodiments that do not limit the scope of the present disclosure to those specific examples.

[0153] Specific details are given in the specification to provide a thorough understanding of the embodiments. However, the embodiments can be implemented without these specific details. For example, in order to avoid confusing the embodiments, well-known circuits, processes, systems, structures and techniques have been shown without unnecessary details. This specification only provides example embodiments and is not intended to limit the scope, applicability or configuration of the present invention. On the contrary, the foregoing description of the embodiments will provide enabling descriptions for realizing various embodiments for those skilled in the art. Various changes can be made to the functions and arrangements of the elements without departing from the scope of the present disclosure.

[0154] Although the various figures show the operation of a particular component or a particular group of components relative to one eye, those skilled in the art will appreciate that similar operations can be performed relative to the other eye or both eyes. For the sake of brevity, such details are not repeated herein.

[0155] Although some of the various figures show multiple operations in a particular order, operations that are not dependent on the order may be reordered, and other operations may be combined or separated. Although specific reference is made to certain reorderings or other groupings, other reorderings or groupings will be apparent to one of ordinary skill in the art, and thus the orderings and groupings presented herein are not an exhaustive list of alternatives. Furthermore, it should be appreciated that the levels may be implemented in hardware, firmware, software, or any combination thereof.

[0156] For purposes of explanation, the foregoing description has been described with reference to specific embodiments. However, the illustrative discussion above is not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed. In light of the above teachings, many modifications and variations are possible. The embodiments were chosen in order to best explain the underlying principles of the claims and their practical application, thereby enabling those skilled in the art to best use the embodiments with various modifications suitable for the specific use contemplated.

Claims

1. An optical device, comprising: a first electrode; as well as A medium comprising ferroelectric liquid crystal and a chiral dopant, wherein the medium is located adjacent to the first electrode.

2. An optical device according to claim 1, wherein: The first electrode is transparent.

3. The optical device according to claim 1, further comprising: A second electrode is different from the first electrode and is spaced apart from the first electrode.

4. An optical device according to claim 3, wherein: The second electrode is transparent.

5. The optical device according to claim 3, wherein: The first electrode extends along a first plane; and The second electrode extends along a second plane, which is parallel to the first plane and deviates from the first plane.

6. The optical device according to claim 3, wherein: The first electrode and the second electrode extend along a common plane.

7. The optical device according to claim 3, wherein: The first electrode is spaced apart from the second electrode by at least 20 μm.

8. The optical device according to claim 1, further comprising: A first substrate is located adjacent to the first electrode.

9. The optical device according to claim 8, further comprising: A second substrate is different from the first substrate and is spaced apart from the first substrate.

10. The optical device according to claim 9, wherein: The first substrate is spaced apart from the second substrate by at least 1 μm.

11. The optical device according to claim 9, further comprising: A first optical polarizer.

12. The optical device according to claim 11, further comprising: a second optical polarizer, the second optical polarizer being different from the first optical polarizer, wherein: The first optical polarizer is located adjacent to the first substrate, and the second optical polarizer is located adjacent to the second substrate; or The first optical polarizer is located adjacent to the second substrate, and the second optical polarizer is located adjacent to the first substrate.

13. The optical device according to claim 1, wherein the ferroelectric liquid crystal comprises one or more selected from the group consisting of: an aromatic mesogen having a 2,5-substituted 1,3-dioxane group, an aromatic mesogen having two or more oriented ester bonds and a nitro terminal group, and an aromatic ester mesogen having a nitrile terminal group.

14. The optical device according to claim 1, wherein: The ferroelectric liquid crystal includes one or more selected from the group consisting of a rod-shaped material having a 1,3-dioxane group, 4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate, and 15. The optical device according to claim 1, wherein: The chiral dopant includes one or more selected from the group consisting of: ZLI811, BDH1281, R5011 and S5011.

16. The optical device according to claim 1, wherein: The chiral dopant includes one or more selected from the group consisting of R2011, S2011, R1011, S1011, CB15, S811 and CBI15.

17. A head mounted display device, the head mounted display device comprising: Display panel; as well as The optical device according to claim 1, wherein the optical device is located adjacent to the display panel so that light passing through the optical device is irradiated onto the display panel.

18. A method comprising: providing a first voltage gradient at a first time between a first electrode and a second electrode, the second electrode being different from and spaced apart from the first electrode, wherein a medium including a ferroelectric liquid crystal and a chiral dopant is located at least adjacent to the first electrode; and A second voltage gradient is provided between the first electrode and the second electrode at a second time mutually exclusive from the first time, the second voltage gradient being smaller than the first voltage gradient.

19. The method of claim 18, wherein: The first voltage gradient is less than 0.2 V / μM.

20. The method of claim 19, wherein: The first voltage gradient is greater than 0.018 V / μm; and The second voltage is less than 0.018 V / μM.

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