Optical element and method for designing electrode of optical element

Abstract

To disclose a method for designing an electrode pattern for obtaining an optical element.SOLUTION: The method includes: determining a refractive index profile of an active material (602) included in an optical element (600); determining, on the basis of the refractive index profile, a voltage profile indicating the voltage distribution to be applied along the radial direction of the active material or the optical axis in order to cause a change of the refractive index of the active material corresponding to the refractive index profile; generating an electrode pattern (500) constituting a set of segments associated with a set of resistors and having a pair of end terminals; and depositing an electrode pattern on the active material for applying the voltage distribution along the radial direction of the active material or the optical axis when a set of drive voltages is applied to the pair of end terminals, and obtaining an optical element.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The disclosure of this application (hereinafter referred to as the present disclosure) relates to electrode design for an optical device. The disclosure also relates to an optical element and an electrode design method for an optical element.

[0002] An optical lens assembly may include one or more optical elements and an active material. The active material has certain properties, such as physical properties, chemical properties, or anisotropic optical properties, that allow the active material to be controlled using various means. The active material may be controlled using various means, such as electrical, magnetic, or mechanical, to generate different optical powers in different portions or regions of one or more optical elements. The active material may be, for example, a liquid crystal material disposed within a thin liquid crystal cell. The liquid crystal material may be controlled by applying an electric field. The application of an electric field changes the orientation of the liquid crystal molecules in the liquid crystal material. The liquid crystal molecules align in the direction of the electric field, which causes a change in the refractive index of the liquid crystal material. The change in refractive index may be due to anisotropic optical properties of the liquid crystal material, such as birefringence. The birefringence property allows the use of liquid crystal materials in designing electronically tunable optical elements, such as lenses.

[0003] The change in refractive index of the liquid crystal material, or any active material, may follow a specific pattern. To change the refractive index through the application of an electric field, different voltages may be applied across the active material. The voltage application can use a specific electrode pattern that distributes the voltage according to a desired optical profile. Traditionally, the electrode pattern generates a voltage that follows the desired profile of the optical element. In the case of an optical element (such as a lens), the optical profile may follow a spherical or parabolic pattern. The electrode pattern is then designed to create a voltage distribution scheme, i.e., a change in voltage applied across the active material that follows a spherical or parabolic pattern. Such patterns assume that the change in refractive index with respect to the applied voltage is linear, which is generally only true over a limited voltage range. Therefore, the use of a voltage distribution scheme across the active material may limit the optical power that can be generated by the optical element and / or the aperture of the optical element.

[0004] Alternatively, electrodes placed in different regions of the active material can be individually controlled with different voltages. This allows for the application of any desired electric field profile across the active material, resulting in any desired change in refractive index. To fully utilize this approach, the device must incorporate an electronic control device (processor) capable of applying multiple independent voltages to the various regions of the active material, and the electrode pattern on the active material must be designed so that these control voltages are applied to the correct locations without interfering with each other. This can be achieved, for example, by placing independent electrodes in each of the various regions, with the electrodes in different layers electrically isolated from each other. This implementation can potentially complicate the manufacturing process of the active optical element.

[0005] In light of these considerations, a need exists to overcome the aforementioned shortcomings.

[0006] It is an object of the present disclosure to provide an optical element and a method for designing electrodes of an optical element to obtain patterned electrodes that may allow for applying a voltage distribution across the active material of the optical element, such that the full range of tunable individual properties (such as birefringence) of the active material is exploited to achieve an increased optical power and / or a larger aperture of the optical element and to reduce the number of Fresnel zones required. The object of the present disclosure is achieved by an optical element and a method for designing electrodes of an optical element as defined in the attached independent claims. Advantageous features are set out in the attached dependent claims. [Brief explanation of the drawings]

[0007] [Figure 1] 1 illustrates steps in a method for designing electrodes for an optical element, according to one embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of an optical lens assembly according to an embodiment of the present disclosure. [Figure 3] 1 is a graph illustrating a target refractive index profile for an active material included in an optical element according to one embodiment of the present disclosure. [Figure 4] 1 is a graph illustrating a voltage profile showing the voltage distribution applied on the active material of an optical element according to one embodiment of the present disclosure. [Figure 5] 1 illustrates an exemplary electrode pattern deposited on the active material of an optical element according to one embodiment of the present disclosure. [Figure 6] 1 illustrates an exemplary optical element obtained based on the deposition of an electrode pattern onto an active material, according to one embodiment of the present disclosure. [Figure 7] 7A-7C are cross-sectional views of exemplary optical elements including two optically transparent substrates and an active element according to various embodiments of the present disclosure. [Figure 8] 1 illustrates an exemplary optical element that can function as a Fresnel lens, according to one embodiment of the present disclosure. Detailed Description of the Embodiments

[0008] The following detailed description illustrates embodiments of the present disclosure and how they may be practiced. Although several forms for carrying out the present disclosure have been disclosed, those skilled in the art will recognize that other forms for carrying out the present disclosure are also possible. Throughout the description and claims of this specification, the terms "comprise," "include," "have," and the like mean the inclusion of a certain element, but not only that element. They do not exclude the presence of other components, items, numbers, or steps not expressly disclosed. Furthermore, unless the context dictates otherwise, the singular also encompasses the plural. In particular, where the original text uses an indefinite article, the specification contemplates the plural as well as the singular unless the context requires otherwise.

[0009] According to a first aspect, the present disclosure provides a method for designing an electrode pattern for an optical element, the method comprising: determining a refractive index profile of an active material included in the optical element, the refractive index profile exhibiting a first change in refractive index difference along a radial or optical axis of the active material; determining a voltage profile indicative of a voltage distribution to be applied along a radial or optical axis of the active material based on the refractive index profile, wherein application of the voltage distribution causes a change in the refractive index of the active material corresponding to the refractive index profile; generating at least one electrode pattern, each of the at least one electrode pattern having a pair of end terminals, each of the at least one electrode pattern constituting a set of segments associated with a set of resistors, the set of resistors enabling application of the voltage distribution along a radial or optical axis of the active material when a set of drive voltages is applied to the pair of end terminals; obtaining the optical element by depositing the at least one electrode pattern on the active material, wherein the deposition enables application of the voltage distribution along a radial or optical axis of the active material when the set of drive voltages is applied to the pair of end terminals; Includes.

[0010] According to a second aspect, the present disclosure provides an optical element, the optical element comprising: a pair of optically transparent substrates including a first substrate and a second substrate; an active substance encapsulated between the first substrate and the second substrate; a set of electrode patterns deposited on a first surface of the active material; and Any electrode pattern belonging to the set of electrode patterns is deposited on the first substrate; Each of the electrode patterns in the set of electrode patterns has a pair of end terminals; Each electrode pattern belonging to the set of electrode patterns constitutes a set of segments; Each segment in the set of segments is associated with one of the resistors in the set of resistors; the set of resistors enables application of the voltage distribution along a radial or optical axis of the active material when a set of drive voltages is supplied to the pair of end terminals of the electrode patterns belonging to the set of electrode patterns; Application of the voltage distribution results in a change in the refractive index of the active material.

[0011] The present disclosure provides a first aspect and a second aspect for producing at least one electrode pattern that can be deposited on the active material of an optical element. The method enables precise control of the refractive index in the active material by applying a tailored voltage profile through the segmented electrode pattern, resulting in improved optical performance and enabling real-time manipulation of light within the optical element. The method provides precise, predetermined control of the refractive index profile within the active material through a voltage profile applied using at least one electrode pattern (i.e., a segmented electrode pattern). The method ensures that the voltage distribution precisely matches the refractive index change (i.e., the first change) along the radial or optical axis of the material. The segmentation of the electrode and its associated resistance allows for fine tuning of the voltage across the active material, leading to optimized light manipulation. This results in improved optical performance and allows for real-time tuning of how light interacts with the optical element for a variety of applications. The optical element is configured to respond to the voltage precisely as designed, resulting in reliable and repeatable optical behavior.

[0012] In some embodiments, a single electrode pattern may be deposited on the active material. The electrode pattern may comprise a set of resistors that allow the refractive index of the active material to be changed linearly or nonlinearly based on the application of an electric field to the active material. The application of the electric field may include supplying a set of drive voltages to a pair of end terminals of the electrode pattern. The set of drive voltages and the set of resistors of the electrode pattern may achieve the application of a voltage distribution (i.e., electric field) along the radial or optical axis of the active material.

[0013] The active material may include a set of regions, each of which may be circular or axially elongated. Each region of the set may require a voltage to be applied to facilitate application of a voltage distribution along the radial or optical axis. A set of resistors comprising an electrode pattern may allow for application of a specific voltage to each region of the active material. The set of regions may be in contact with a set of segments of the electrode pattern, i.e., each segment of the set of segments may be deposited on a respective region of the set of regions of the active material. Each segment of the electrode pattern may represent a resistor of a set of resistors that allows for application of a specific voltage range to each region of the set of regions, and that allows for application of a voltage distribution along the radial or optical axis when a set of drive voltages is applied to a pair of end terminals.

[0014] Applying a specific range of voltages to each region of the active material, with a specific resistor represented by the segment of the electrode pattern in contact with that region, can result in a change in the refractive index of that region. The change in refractive index of each region can be individualized by applying a specific range of voltages. In this way, a single set of resistors facilitates utilization of the entire birefringence range of the active material. Utilizing the entire birefringence range can enable the design of optical elements with increased electronic tunability (available optical power range) and / or aperture.

[0015] Throughout this disclosure, the term "optical element" may refer to an optical element capable of varying optical power. The optical power may be positive or negative, which may be used to focus or defocus light. The optical element may be controllable to generate different optical powers at different portions of the optical element. The optical element may include a pair of optically transparent substrates. The pair of optically transparent substrates may include two substrates, i.e., a first substrate and a second substrate. The optical element may further include an active material. The active material is encapsulated between the first and second substrates. In the optical element, the optical power may be generated based on generating a difference between the refractive indexes of different regions of the active material. In this manner, multiple different optical powers may be generated based on generating a difference between the refractive indexes of each of the multiple different regions of the active material. The difference in refractive index is achieved by applying different electric fields (i.e., voltages) to the active material regions, thereby varying the refractive index of each region of the active material. The optical element may be part of an optical lens assembly. The optical lens assembly may be used in eyeglasses, sunglasses, head mounted displays (HMDs), virtual reality (VR), mixed reality (MR), or augmented reality (AR) devices.

[0016] In some embodiments, at least one of the first substrate or the second substrate may have a set of circular grooves. Each of the set of circular grooves may contact a different region of the active material, i.e., each region of the active material is in contact with a circular groove. The circular grooves in the set may be concentric. Different optical powers may be generated by the grooves.

[0017] Throughout this disclosure, the term "active material" may refer to a material with anisotropic optical properties, whose refractive index can be controlled (or varied) to generate a specific light output in a specific region of the active material. One example of an active material is a nematic liquid crystal material. Because a nematic liquid crystal material experiences a change in refractive index only for one polarization state of light, determined by the predetermined orientation of the liquid crystal molecules, a polarization-independent optical element can have multiple optical elements with orthogonal polarization states stacked on top of each other. Application of an electric field to the active material can control the orientation of the liquid crystal molecules in different regions of the liquid crystal material. In some embodiments, the different regions of the active material may refer to circular regions that may be concentric. That is, the different regions may all have a common center, which may be the center of the active material. In other embodiments, the different regions may be located at different distances from each other along an optical axis that passes through the center of the active material. Controlling the alignment of the liquid crystal molecules can change the refractive index of various regions of the liquid crystal material. Based on this change in refractive index, different optical powers can be generated in different regions of the active material.

[0018] The refractive index profile of the active material may be determined based on the desired optical profile of the active material. The refractive index profile indicates a first change in refractive index difference along the radial or optical axis of the active material. In some embodiments, the optical profile may refer to the optical path difference (OPD), typically expressed in units of the design wavelength of the optical device. The OPD may indicate the delay that a light ray may experience while passing through each region of a set of regions of the active material. The delay may be due to the different effective distances that the light ray may travel while passing through different regions of the active material due to the refractive index difference. In some embodiments, the OPD profile may correspond to a spherical or aspherical surface, such as a paraboloid, a negative lens, a positive lens, a cylindrical lens, a diffraction grating, a phase plate, or an optical wedge prism.

[0019] Once the desired OPD profile of the active material is determined, a refractive index difference Δn for various locations along the radial or optical axis can be determined based on the determined OPD, the design wavelength λ (i.e., the wavelength at which the optical element is designed to function), and the thickness d of the active material layer of the optical element from the formula Δn = OPDλ / d. The refractive index difference for a particular location (e.g., a first location) may be the difference between the refractive index at the first location on the radial or optical axis and the refractive index at a second location where the OPD is "0." The OPD may be zero at the center of the active material. Thus, a refractive index difference may be determined for each first location in the set of first locations, where the refractive index difference represents the difference between the refractive index at each first location and the refractive index at a second location on the radial or optical axis. Thus, the first change may be a change in the determined refractive index difference (Y-axis) that can be associated with the set of first locations along the radial or optical axis (X-axis) of the active material. The first change represents a refractive index profile. An exemplary refractive index profile (i.e., first change) is depicted in FIG. 3.

[0020] The voltage profile is determined based on the refractive index profile. The voltage profile indicates a voltage distribution to be applied along a radial or optical axis of the active material to generate an electric field that changes the refractive index of the active material and thereby produces a target refractive index. The voltage distribution may include a set of voltages that may be required to be applied to a first set of locations along the radial or optical axis of the active material. Each first location in the first set of locations is located in a different region of the active material. Application of the voltage distribution causes a change in the refractive index of the active material corresponding to the refractive index profile. The voltage distribution is configured to precisely adjust the refractive index of the active material to match the determined refractive index profile. The voltage profile is derived from the refractive index profile to precisely determine the voltage distribution required to produce the required change in the refractive index of the active material. Any voltage in the set of voltages applied to any first location in the radial or optical axis of the first set of locations may produce a change in the refractive index at the associated first location. The change in refractive index may be such that the difference between the refractive index at the corresponding first location (after the voltage is applied) and the refractive index at the second location (where the OPD is "0") matches the refractive index difference associated with the corresponding first location, as shown in the refractive index profile. The number of first locations in the set of first locations may vary depending on the implementation of the optical element. Accordingly, the number of voltage levels that may be included in the set of voltages (i.e., the voltage distribution) may also vary depending on the implementation. An exemplary plot of a voltage profile (i.e., the voltage distribution) is shown in FIG. 4.

[0021] In some embodiments, the voltage profile is determined based on a second change in the refractive index of the active material in response to a voltage applied to the active material. The second change is determined based on at least one of a set of active material properties and a set of active material parameters. The second change may represent the refractive index response of the active material in a particular type of liquid crystal cell when a set of voltages is applied to the active material. The second change can be determined by experimental measurements, such as polarization interferometry or ellipsometry, or by numerical modeling, provided that the properties of the active material, such as elastic constant, dielectric anisotropy, and birefringence, are known. For example, the active material may be a liquid crystal material whose refractive index varies between 1.8 and 1.55 based on the application of a set of voltages ranging from 0 to 16 volts. After determining the second change, a polynomial or other approximation function including a set of coefficients representing the second change is fitted. The fitted polynomial or function may then be used to determine the voltages that may need to be applied to change the refractive index at each of the first locations in the set of first locations. The change in refractive index must be such that the difference between the refractive index at the first location corresponding to that refractive index (after application of the determined voltage) and the refractive index at the second location matches the difference in refractive index that may be associated with that first location (as shown in the refractive index profile).

[0022] In another embodiment, linear interpolation may be used to determine from the measured or simulated second change the voltage that needs to be applied at the corresponding first location.

[0023] A portion of the second change may be linear or nearly linear, while the remainder of the second change may be nonlinear. For example, the refractive index of the active material may decrease linearly from 1.79 to 1.69 with the application of a voltage between 2 and 4 volts. To access the entire birefringence range of the active material, the second change may be divided into multiple portions. Each of the multiple portions of the second change may be linear. That is, the refractive index of the active material may decrease or increase linearly with increasing or decreasing voltage applied to the active material. To achieve a similar effect, a set of voltages (i.e., a voltage distribution) may be applied to a set of regions of the active material. Application of a voltage to a particular region of the active material changes the orientation of the molecules contained in that region. These changes in molecular orientation may result in a change in the refractive index of that region. The region may include a subset of the first set of locations along the radial or optical axis of the active material. The difference between the refractive index at each first location in the subset (after application of any voltage in the set of voltages) and the refractive index at a second location (where the OPD is 0) may match the refractive index difference for that first location as shown in the refractive index profile.

[0024] At least one electrode pattern may be generated to enable application of a voltage distribution (represented by a voltage profile) along the radial or optical axis of the active material. Each electrode pattern includes a pair of end terminals. Each electrode pattern comprises a set of segments associated with a set of resistors. Each electrode pattern is strategically designed so that application of a set of drive voltages to the pair of end terminals results in a (desired) voltage distribution along the radial or optical axis of the active material. In some embodiments, a single electrode pattern having a pair of end terminals may be generated. The set of segments of the generated electrode pattern may be arranged consecutively in series, and thus the electrode pattern may comprise a set of resistors. This set of resistors enables application of a voltage distribution along the radial or optical axis of the active material when a set of drive voltages is applied to the pair of end terminals of the electrode pattern. Applying a set of drive voltages to the pair of end terminals and each resistor in the set may enable application of one of the voltages (i.e., voltage distribution) to each region of the set of regions of the active material. Each of the regions may comprise a subset of first locations along the radial or optical axis of the active material. In some embodiments, when each region of the set of regions is a circular region, each segment of the set of segments of the electrode pattern may also be circular and comprise the subset of first locations. Furthermore, each of the segments may allow application of any voltage in the set of voltages through a resistance with which the segment may be associated in the set of resistors.

[0025] This method allows for precise and predetermined control of the refractive index and controlled voltage distribution through carefully designed electrode patterns and resistors, resulting in accurate and reliable optical performance, and can therefore be employed to reliably and reproducibly obtain optical elements with desired optical behavior.

[0026] In some embodiments, the set of drive voltages may include a first drive voltage and a second drive voltage. The first drive voltage is supplied to a first end terminal of each pair of end terminals of the electrode pattern, and the second drive voltage is supplied to a second end terminal of each pair of end terminals of the electrode pattern. In some embodiments, the set of drive voltages applied to the pair of end terminals of the electrode pattern may include two voltages, V1 and V2. The set of drive voltages may be selected based on a second change, i.e., the refractive index response of the active material when the set of voltages is applied to the active material. The voltage level of V1 may be selected from among the lower voltages of the set of voltages applied to the active material, and the voltage level of V2 may be selected from among the higher voltages of the set of voltages. This selection may be made such that application of V1 and V2 to the pair of end terminals of the electrode pattern causes each resistor in the set of resistors to apply a set of voltages to each region of the set of regions of the active material.

[0027] In some embodiments, the active material may be a nematic liquid crystal containing rod-shaped (i.e., calamitic) or disk-shaped (discotic) mesogenic molecules. The voltage level selected for V1 may be close to the threshold voltage of the mesogenic molecules. For example, the voltage level may be selected from a voltage range of 2.8 to 3.5 volts. The voltage level for the driving voltage V2 may be determined based on the characteristics of the liquid crystal. This characteristic may be represented by a refractive index profile, which indicates the refractive index difference for different regions of the liquid crystal (i.e., a first set of positions along the radial or optical axis of the liquid crystal). If the voltage level is too high, the liquid crystal may saturate, i.e., the refractive index may not change (decrease) at such a voltage level. Saturation of the liquid crystal due to too high a voltage may limit the electronic tunability, size, and aperture of the optical element. Therefore, the voltage level for V2 may correspond to a voltage level close to the saturation plateau (in the second change or refractive index response). For example, the voltage level may be selected to be 13 volts.

[0028] In some embodiments, the set of resistors may correspond to a set of resistance values. In some embodiments, for a generated electrode pattern, all resistors in a set of resistors associated with a set of segments of the generated electrode pattern may correspond to different resistance values. In such embodiments, the number of possible resistance values ​​included in the set of resistors may be the same as the number of segments included in the set of segments. Each segment included in the set of segments may be designed to have a width or thickness different from the other segments included in the set of segments. In another embodiment, the generated electrode pattern may be such that each resistor included in a subset of the set of resistors is associated with one of the resistance values ​​included in the set of resistance values. Each segment included in the set of segments may be designed to have the same width or thickness as the other segments included in the set of segments.

[0029] In some embodiments, each segment in a set of segments in each electrode pattern may be associated with one of the resistors in the set of resistors. For example, the set of resistors may include eight resistors, i.e., R1, R2, ... R8. The set of segments may include eight segments, i.e., S1, S2, ... S8. The first segment (i.e., S1) may be associated with the first resistor (i.e., R1). Similarly, the eighth segment (i.e., S8) may be associated with the eighth resistor (i.e., R8). In some embodiments, the resistance value of each resistor in the set of resistors associated with each segment in the set of segments may be controlled by varying the thickness of the segment and / or patterning the segment with a set of holes. The resistance value of a particular resistor (e.g., R1) can be increased by decreasing the thickness or width of the segment or increasing the length of the segment (e.g., S1) associated with that resistor. Conversely, the resistance value of a resistor can be decreased by increasing the thickness or width of the segment associated with that resistor or decreasing the length of the segment. In some embodiments, the resistance value of each resistor in the set of resistors associated with each segment in the set of segments may be controlled by patterning the segment with holes to increase the resistance value of the segment.

[0030] In some embodiments, the first end terminal of each electrode pattern may be coupled to a first segment of the set of segments, and the second end terminal of the electrode pattern may be coupled to a second segment of the set of segments. The first and second segments are end portions of the electrode pattern. Each of the first and second segments may be connected to any of the set of segments. Each segment of the set may be connected to two other segments of the set, excluding the first and second segments. Thus, both ends of each segment other than the first and second segments are connected to the other segments of the set. An exemplary electrode pattern is illustrated in FIG. 5. As shown, the electrode pattern has a pair of end terminals. The electrode pattern also comprises a set of segments, each of which is coupled to the other segments and end terminals.

[0031] The generated at least one electrode pattern may be deposited on an active material to obtain an optical element. The deposition of the at least one electrode pattern on the active material allows for the application of a voltage distribution along the radial or optical axis of the active material when a pair of drive voltages is supplied to a pair of end terminals of the electrode pattern. In some embodiments, a single electrode pattern may be deposited on the active material. The electrode pattern may be deposited as a transparent electrode layer comprising a set of segments that can be connected to each other. The transparent electrode layer may be formed of indium tin oxide (ITO) or doped zinc oxide (ZnO). The ZnO may be doped with aluminum or hydrogen. In some embodiments, the transparent electrode layer may be formed of a conductive polymer or graphene.

[0032] Each segment of the set of segments associated with each resistor of the set of resistors may be deposited on a respective region of the set of regions of the active material. When a first drive voltage is applied to a first end terminal and a second drive voltage is applied to a second end terminal, the set of resistors may cause the application of a set of voltages (i.e., a voltage profile) across the set of regions. Specifically, in each region, the resistor associated with that region may cause the application of a voltage from the set of voltages that matches the voltage profile. This effect may be due to the segment associated with that resistor being deposited on the corresponding region of the active material. A voltage may be applied at a subset of the first locations within the region along a radial or optical axis of the active material.

[0033] Application of voltages at a subset of first locations within each region may result in a change in refractive index at that subset of first locations. The change may be such that the difference between the refractive index at each first location and the refractive index at each second location within the subset of first locations matches the refractive index difference indicated in the refractive index profile for each first location. Prior to application of a set of voltages to a set of regions of the active material, the refractive index of the active material may match the refractive indices of the first and second substrates that generate the base optical power. Application of a set of voltages to a set of regions (achieved by a set of resistors when a set of drive voltages is supplied to a pair of end terminals) may result in a refractive index difference between the active material and the first substrate or between the active material and the second substrate. The refractive index difference may result from a change in refractive index within the set of regions of the active material. The change may be different for each of the regions within the set that are in contact with different portions of the first substrate or the second substrate. Different variations can produce optical path difference profiles corresponding to optical elements such as spherical and aspherical lenses.

[0034] In some embodiments, the at least one electrode pattern may be deposited on a first substrate, which may be in contact with the first or second layer of active material. The at least one electrode pattern may be deposited using a patterned deposition mask, which may be deposited using laser writing or lithography. An electrode providing a ground voltage may be deposited on a second substrate in contact with the second layer of active material, which may be a continuous or patterned layer of conductive material.

[0035] The second layer of active material may be located on the opposite side of the first layer of active material. Thus, the first layer contacts the first substrate, the second layer contacts the second substrate, and the at least one electrode pattern is located between the first layer and the first substrate. Applying a set of voltages (i.e., a voltage distribution) to the first layer (since the at least one electrode pattern is deposited on the first layer) and a ground voltage to the second layer can result in a potential difference (electric field) between the at least one electrode pattern and the electrode providing the ground voltage. This potential difference can result in a change in the optical properties of the active material (e.g., the orientation of nematic molecules of a liquid crystal material).

[0036] In some embodiments, the optical element may include a substrate that is a plano-convex lens, a plano-concave lens, or a Fresnel lens. The substrate may be the first substrate. When the substrate (i.e., the first substrate) is a Fresnel lens, the at least one electrode pattern may follow a continuous spiral pattern. The Fresnel lens may include a plurality of grooves that may contact a set of segments of each electrode pattern. The Fresnel lens may be optically transparent and include a set of concentric grooves. The set of segments constituting the electrode pattern may be deposited on the set of concentric grooves. A set of regions of the first layer of active material, including a set of first positions along the radial or optical axis of the active material, may contact the set of concentric grooves. The set of segments may be located between the set of concentric grooves and the set of regions of the Fresnel lens (i.e., the first substrate). An exemplary electrode pattern having a continuous spiral pattern deposited on an active material is shown in FIG. 8.

[0037] The present disclosure also relates to the second aspect as described above, and the various embodiments and modifications disclosed above with respect to the first aspect also apply mutatis mutandis to the second aspect.

[0038] In some embodiments, the change in refractive index may correspond to a refractive index profile that indicates a first change in refractive index difference along a radial or optical axis of the active material, and the voltage distribution is determined based on the refractive index profile and a second change in the refractive index of the active material in response to a voltage applied to the active material.

[0039] The technical effect of determining the voltage distribution based on the refractive index profile and the second change is to enable application of a set of voltages along a radial or optical axis of the active material such that the refractive index of the active material undergoes a change. The change in the refractive index of the active material may vary depending on the region of the active material. This may result from application of a set of voltages at each region of the set of regions of the active material. The change in refractive index may correspond to a refractive index profile that indicates a first change in refractive index difference along the radial or optical axis of the active material. The set of regions may include a first set of locations along the radial or optical axis of the active material, and each region of the set may include a subset of the first locations along the radial or optical axis of the active material. Based on application of voltages at the subset, the refractive index at each of the first locations in the subset may undergo a change such that the difference between the refractive index at the first location and the refractive index at a second location (where the OPD is zero) is equal to (or matches) the refractive index difference for the first location as shown in the refractive index profile.

[0040] In some embodiments, the set of resistors corresponds to a set of resistance values.

[0041] A technical advantage of associating a set of resistors with a set of resistance values ​​is that it allows for designing each electrode pattern belonging to the set of electrode patterns, where each electrode pattern constitutes a set of segments, and all segments belonging to the set of segments have different widths. In some scenarios, the set of segments can include multiple subsets, and each of the subsets (of segments) can be associated with one of the resistance values ​​in the set of resistance values. Associating the set of resistors with the set of resistance values ​​allows for application of a set of voltages at the set of regions of the active material where the set of segments can be deposited (i.e., a set of first locations along the radial or optical axis). Application of different voltages can be attributed to a set of resistors associated with a set of segments.

[0042] In some embodiments, each segment in the set of segments of each electrode pattern in the set of electrode patterns may be associated with a resistor in the set of resistors, and the resistance value of each resistor in the set of resistors may be controlled based on at least one of varying the thickness or width of the corresponding segment, or patterning the corresponding segment with holes.

[0043] A technical advantage of varying or patterning the thickness or width of a set of segments is that each segment can be associated with a different resistance. Depositing a set of segments (which make up each electrode pattern) allows for the application of a set of voltages (i.e., voltage distribution) to a set of areas of active material.

[0044] In some embodiments, the set of drive voltages may include a first drive voltage and a second drive voltage, wherein the first drive voltage is supplied to a first end terminal of a pair of end terminals of each electrode pattern belonging to the set of electrode patterns, and the second drive voltage is supplied to a second end terminal of the pair of end terminals of each electrode pattern belonging to the set of electrode patterns.

[0045] In some embodiments, the set of electrode patterns includes only a single electrode pattern, and the first end terminal of the pair of end terminals is supplied with the first drive voltage and the second end terminal is supplied with the second drive voltage.

[0046] In some embodiments, a first end terminal of each electrode pattern in the set of electrode patterns may be coupled to a first segment of the set of segments comprising that electrode pattern, and a second end terminal of each electrode pattern in the set of electrode patterns may be coupled to a second segment of the set of segments comprising that electrode pattern.

[0047] A technical advantage of providing a first drive voltage and a second drive voltage to the first end terminal and the second end terminal of each pair of end terminals of a set of electrode patterns, respectively, is that a set of resistors (i.e., a set of segments) can cause a set of voltages (i.e., a voltage distribution) to be applied when the electrode patterns are deposited on a particular region of the active material. The application of a set of voltages may be achieved using only two voltage levels (i.e., V1 and V2) that can be supplied to the pair of end terminals of the electrode patterns. The application of a set of voltages causes a change in the refractive index of the active material in that region. This change may be different for each region of the active material. This change may result in a difference between the refractive index of the active material and the refractive index of the first substrate in different portions of the first substrate (which may be in contact with different regions of the active material). The difference in the refractive index between the active material and the substrate in different portions of the active material may result in different optical powers being generated in different portions of the optical element.

[0048] In some embodiments, the first substrate is a plano-convex lens, a plano-concave lens, or a Fresnel lens. Additional optical elements, such as lenses or polarizers, may be incorporated into the assembly of active optical elements by being implemented as a substrate or by being placed on the same optical path via other means. The Fresnel lens includes a plurality of grooves, each groove of which contacts a respective segment of a set of electrode patterns belonging to the set of electrode patterns. Each electrode pattern of the set of electrode patterns is associated with one of the Fresnel zones of the set of Fresnel zones.

[0049] The Fresnel lens may include a set of circular grooves that may extend through a set of Fresnel zones. Each segment of the set of segments may constitute one of the electrode patterns and may be in contact with one of the circular grooves, allowing one of the voltages in the set of voltages to be applied to the associated circular groove. Each segment of the set of segments of the electrode pattern may be circular and in contact with at least one other segment of the set of segments, forming a continuous spiral pattern (i.e., electrode pattern). Application of a set of voltages to each circular groove may cause a linear or nonlinear change in the refractive index of each of the set of regions of active material in contact with the circular groove.

[0050] A technical advantage of associating each segment of a set of segments with a resistance value of a set of resistors based on a second variation of the active material is that the full range of birefringence of the active material (e.g., liquid crystal material) can be utilized to generate optical power by simply applying two voltage levels to a pair of end terminals of the electrode pattern, thereby enabling optical elements with a wide range of tunable optical power and large aperture sizes. [Detailed description of the drawing]

[0051] Referring to FIG. 1, steps of an electrode design method for an optical element according to one embodiment of the present disclosure are depicted. In step 102, a refractive index profile of an active material included in the optical element is determined. The refractive index profile indicates a first change in refractive index difference along the radial or optical axis of the active material. In step 104, a voltage profile indicating a voltage distribution to be applied along the radial or optical axis of the active material is determined based on the refractive index profile of the active material and a second change in refractive index. Application of the voltage distribution causes a change in the refractive index of the active material corresponding to the refractive index profile. In step 106, an electrode pattern having a pair of end terminals is generated. The electrode pattern comprises a set of segments associated with a set of resistors. The set of resistors enables application of a voltage distribution along the radial or optical axis of the active material when a set of drive voltages is applied to the pair of end terminals. In step 108, an optical element is obtained by depositing the electrode pattern on the active material. This deposition enables application of a voltage distribution along the radial or optical axis of the active material when a set of drive voltages is applied to the pair of end terminals.

[0052] The steps described above are merely exemplary, and alternative steps may be included, i.e., one or more steps may be added, one or more steps may be removed, or one or more steps may be performed in a different order, without departing from the scope of the appended claims.

[0053] Referring to FIG. 2, a schematic diagram of an optical lens assembly 200 according to one embodiment of the present disclosure is shown. The optical lens assembly 200 includes an optical element per square, depicted as optical element 202a for the first eye of a user and optical element 202b for the second eye. The optical lens assembly 200 further includes electrode patterns 204a and 204b, active materials 206a and 206b, and a processor 208. The electrode patterns 204a and 204b may enable the application of voltage distributions to be applied along the radial or optical axis of the active materials 206a and 206b, respectively. These voltage distributions are applied to change the refractive index of the active materials 206a and 206b. The processor 208 is configured to apply predetermined drive voltages (V1 and V2) to each pair of end terminals of each of the electrode patterns 204a and 204b.

[0054] 2 depicts a simplified architecture of an optical lens assembly for clarity only, and those skilled in the art will appreciate that FIG. 2 does not unduly limit the scope of the claims herein. It should be understood that the specific implementation of optical lens assembly 200 is provided by way of example only and should not be construed as being limited to any particular type of optical element, electrode pattern, active material, or processor. Those skilled in the art will recognize many variations, alternatives, and modifications of the embodiments of the present disclosure.

[0055] Referring to FIG. 3 , a graph illustrating a target refractive index profile 300 of an active material included in an optical element is shown, according to one embodiment of the present disclosure. The refractive index profile 300 may be determined for an active material that may be included in an optical element. The refractive index profile may indicate a first change in refractive index difference along a radial or optical axis of the active material that may be desired to be achieved by applying a voltage profile to the active material. The radial or optical axis of the active material includes a set of first positions, and the first change constitutes a refractive index difference for the set of first positions. The refractive index difference for each first position in the set of first positions may represent the difference between the refractive index at the corresponding first position and the refractive index at a second position in the active material where the optical path difference is “0.” As depicted in the refractive index profile 300, it may be desired to determine the refractive index difference for each first position in the set of first positions of the active material. Based on the refractive index profile 300, a desired OPD profile may be obtained. For example, based on the refractive index profile 300, a desired OPD profile for a positive Fresnel lens having an active layer thickness of 25 micrometers and associated with a design wavelength of 550 nanometers is obtained. The refractive index profile 300 allows for obtaining a desired OPD profile that utilizes the entire birefringence range of the active material.

[0056] 3 is merely an example and should not unduly limit the scope of the claims herein. One of ordinary skill in the art will recognize many variations, alternatives, and modifications of the disclosed embodiments. For example, the refractive index profile 300 may be different for each of multiple active materials included in the same optical element. The refractive index profile 300 may also be different for different optical elements.

[0057] Referring to FIG. 4, a graph illustrating a voltage profile 400 showing a voltage distribution applied on an active material of an optical element is shown, according to one embodiment of the present disclosure. The voltage profile 400 may be determined based on the refractive index profile 300. In some embodiments, the voltage profile 400 may be determined based on the electro-optical response of the active material. The voltage profile 400 shows a voltage distribution applied to a first set of locations along the radial or optical axis of the active material. The application of the voltage distribution causes a change in refractive index at each of a plurality of first locations along the radial or optical axis. This change corresponds to the refractive index profile 300. The voltage distribution shown in the voltage profile 400 may include a set of voltages that may be required to be applied at the first set of locations along the radial or optical axis of the active material. The active material may include a set of regions. Each region in the set may be located within a subset of the first set of locations. A set of voltages may be required to be applied at each region such that there is a change in refractive index at each first location in the set of first locations along the radial or optical axis of the active material. The change in refractive index may follow a refractive index profile 300.

[0058] 4 is merely an example and should not unduly limit the scope of the claims herein. Those skilled in the art will recognize many variations, alternatives, and modifications of the disclosed embodiments. For example, the voltage profile 400 may be different for each of multiple different active materials included in the optical element.

[0059] Referring to FIG. 5, an exemplary electrode pattern 500 is illustrated for deposition on an active material of an optical element, according to one embodiment of the present disclosure. The exemplary electrode pattern 500 may have a pair of end terminals, including a first end terminal 502a and a second end terminal 502b. The exemplary electrode pattern 500 comprises a set of segments 504a-504g. The set of segments 504a-504g follows a spiral pattern and is associated with a set of resistors. Each segment 504a-504g in the set is associated with a resistor in the set. Each resistor in the set may correspond to a resistance value. The resistance value of each resistor is controlled by varying the thickness, width, or length of the segment associated with the corresponding resistor. In some embodiments, all resistances in the set correspond to a single resistance value. In such embodiments, the thickness, width, and length are selected so that the resistance values ​​of all segments 504a-504g in the set are equal. When a set of segments 504a-504g are deposited on the active material, a set of resistors associated with the set of segments 504a-504g allows for the application of a voltage distribution at a first set of positions along the radial or optical axis of the active material.

[0060] In some embodiments, the first end terminal 502a is coupled to the first segment 504a of the set of segments 504a-504g, and the second end terminal 502b is coupled to the second segment 504g of the set of segments 504a-504g. Each of the first segment 504a and the second segment 504g is connected to one of the segments in the set of segments 504a-504g. The first segment 504a is connected to the third segment 504b, and the second segment 504g is connected to the fourth segment 504f. Each segment in the set of segments 504a-504g, except for the first segment 504a and the second segment 504g, is connected to the other two segments in the set of segments 504a-504g. Each of the third segment 504b, fourth segment 504f, fifth segment 504c, sixth segment 504d, and seventh segment 504e is connected to two other segments in the set of segments 504a-504g, for example, sixth segment 504d is connected to fifth segment 504c and sixth segment 504d.

[0061] FIG. 5 is merely an example and should not unduly limit the scope of the claims herein. Those skilled in the art will recognize many variations, alternatives, and modifications of the disclosed embodiments. For example, electrode pattern 500 can include any number of segments (other than the "7" segments shown in FIG. 5), and the thickness, width, or length of the segments in a set of segments 504a-504g can be the same or different. To achieve a wide range of adjustable optical power or a large aperture, an optical element can include multiple such patterns, thereby forming a Fresnel lens (FIG. 8) with multiple Fresnel zones.

[0062] Referring to FIG. 6 , an exemplary optical element 600 is illustrated based on the deposition of an electrode pattern (such as electrode pattern 500) on an active material 602 in accordance with an embodiment of the present disclosure. The deposited electrode pattern 500 follows a spiral pattern. The deposition of the electrode pattern 500 on the active material 602 enables the application of a voltage distribution (i.e., a set of voltages) along a radius (such as radius 604) or optical axis of the active material 602 when a set of drive voltages is supplied to a pair of end terminals. The set of drive voltages includes a first drive voltage (e.g., V1) and a second drive voltage (e.g., V2). The first drive voltage is supplied to the first end terminal 502a of the pair of end terminals, and the second drive voltage is supplied to the second end terminal 502b of the pair of end terminals.

[0063] The active material 602 may include a set of regions, and each segment of the set of segments 504a-504g may be deposited on each region of the set of regions. The set of regions may include a first set of locations along the radius 604. Applying a first drive voltage to the first end terminal 502a of the pair of end terminals and applying a second drive voltage to the second end terminal 502b may enable a set of resistors (associated with the set of segments 504a-504g) to cause application of a set of voltages (i.e., a voltage distribution) at the first set of locations of the set of regions. Specifically, a subset of the voltages may be applied to a subset of the first set of locations along the radius 604 at each region of the set of regions.

[0064] FIG. 6 is merely an example and should not unduly limit the scope of the claims herein. Those skilled in the art will recognize many variations, alternatives, and modifications of the embodiments of the present disclosure. For example, optical element 600 may be of any shape (other than a circular shape as illustrated in FIG. 6). Also, deposition of electrode pattern 500 (i.e., each of the set of segments 504a-504g) on ​​active material 602 may follow any pattern (other than a spiral pattern as illustrated in FIG. 6).

[0065] 7A-7C, cross-sectional views of exemplary optical elements (e.g., optical element 600) including two optically transparent substrates and an active element (e.g., active material 602) are illustrated, according to various embodiments of the present disclosure. Optical element 600 includes active material 602 and a pair of optically transparent substrates. The pair of optically transparent substrates includes a first substrate 702 and a second substrate 704. Active material 602 is encapsulated between first substrate 702 and second substrate 704. Optical element 600 may have an outer edge 706 that encapsulates active material 602. Electrode pattern 500 is disposed between the first layer of active material 602 and first substrate 702. Electrode 708 is disposed between active material 602 and second substrate 704. Electrode 708 provides a ground voltage to the second layer of active material 602.

[0066] As shown in Figure 7A, the first substrate 702 may be implemented as a plano-convex lens with its convex surface in contact with the active material 602. The curvature of the convex surface may correspond to a predetermined optical power to be generated. Alternatively, as shown in Figures 7B and 7C, the first substrate 702 may be implemented as a Fresnel lens with a set of concentric circular grooves. Each circular groove in the set may be in contact with one of a set of regions on the first layer of active material 602. In this case, the concentric grooves of the Fresnel substrate are shaped to emulate the properties of the plano-convex lens described above.

[0067] The application of a set of voltages (i.e., a voltage distribution) on the first layer, caused by a set of resistors (as the set of segments 504a-504g that make up electrode pattern 500 are deposited on the first layer), and the application of a ground voltage caused by electrode 708 (as electrode 708 provides a ground voltage to the second layer), creates a potential difference between electrode pattern 500 and electrode 708. This potential difference causes a change in the refractive index in various regions of active material 602. The change in refractive index can result in different optical powers in different portions of optical element 600.

[0068] 7C, the second substrate 704 can function as a passive optical element. The second substrate 704 can be implemented as a plano-concave lens. The curvature of the plano-concave lens can correspond to a fixed optical power.

[0069] 7A-7C are merely illustrative and should not unduly limit the scope of the claims herein. The particular implementation of optical element 600 is provided by way of example and is not intended to be limited to any particular arrangement of first substrate 702, second substrate 704, electrode pattern 500, active material 602, and electrode 708, or to any particular curvature of first substrate 702. Those skilled in the art will recognize many variations, alternatives, and modifications of the embodiments of the present disclosure.

[0070] FIG. 8 illustrates an exemplary optical element 900 that can function as a Fresnel lens having multiple Fresnel zones according to an embodiment of the present disclosure. The optical element 900 may include an optically transparent Fresnel substrate having multiple grooves. The Fresnel substrate may span four Fresnel zones 902a-902d, with each Fresnel zone including a subset of the set of grooves. A set of electrode patterns 904a-904d may be deposited on the Fresnel substrate. The Fresnel substrate may be deposited on a first surface of the active material 602 along with the set of electrode patterns 904a-904d. Each of the electrode patterns in the set of electrode patterns 904a-904d has a pair of end terminals, and each of the pair of end terminals is supplied with a set of drive voltages. For example, V1 (i.e., the first drive voltage) is supplied to the first end terminal of the pair of end terminals of each electrode pattern included in the set of electrode patterns 904a to 904d, and V2 (i.e., the second drive voltage) is supplied to the second end terminal.

[0071] Each electrode pattern in the set of electrode patterns 904a-904d constitutes a set of segments. Each segment in the set is associated with a resistor in the set of resistors. The set of resistors allows application of a voltage distribution along the radial or optical axis of the active material 602 when a set of drive voltages is supplied to a pair of end terminals of each electrode pattern in the set of electrode patterns. The application of the voltage distribution causes a change in the refractive index of the active material.

[0072] 8 is merely an example, which should not unduly limit the scope of the claims herein. Those skilled in the art will recognize many variations, alternatives, and modifications of the disclosed embodiments.

Claims

1. A method for designing an electrode pattern to obtain an optical element, comprising the steps of: determining a refractive index profile of an active material included in the optical element, the refractive index profile exhibiting a first change in refractive index difference along a radial or optical axis of the active material; determining a voltage profile indicative of a voltage distribution to be applied along a radial or optical axis of the active material based on the refractive index profile, wherein application of the voltage distribution causes a change in the refractive index of the active material corresponding to the refractive index profile; generating at least one electrode pattern, each of the at least one electrode pattern having a pair of end terminals, each of the at least one electrode pattern constituting a set of segments associated with a set of resistors, the set of resistors enabling application of the voltage distribution along a radial or optical axis of the active material when a set of drive voltages is applied to the pair of end terminals; obtaining the optical element by depositing the at least one electrode pattern on the active material, wherein the deposition enables application of the voltage distribution along a radial or optical axis of the active material when the set of drive voltages is applied to the pair of end terminals; A method comprising:

2. 2. The method of claim 1, wherein the voltage profile is determined based on a second change in refractive index of the active material in response to a voltage applied to the active material, the second change being determined based on at least one of a set of properties of the active material and a set of parameters of the active material.

3. The method of claim 1 or 2, wherein the set of resistors corresponds to a set of resistance values.

4. 10. The method of any preceding claim, wherein each segment in the set of segments is associated with one of the resistors in the set of resistors, and the resistance value of each resistor in the set of resistors is controlled based on at least one of varying the thickness or width of the associated segment or patterning the associated segment with holes.

5. 10. The method of any preceding claim, wherein the set of drive voltages comprises a first drive voltage and a second drive voltage, the first drive voltage being supplied to a first end terminal of the pair of end terminals and the second drive voltage being supplied to a second end terminal of the pair of end terminals.

6. 6. The method of claim 5, wherein the first end terminal is coupled to a first segment of the set of segments, the second end terminal is coupled to a second segment of the set of segments, each of the first segment and the second segment is connected to one of the segments of the set of segments, and each segment included in the set of segments is connected to two other segments included in the set of segments, excluding the first segment and the second segment.

7. 10. The method of any preceding claim, wherein the optical element comprises a substrate, the substrate being a plano-convex lens, a plano-concave lens, or a Fresnel lens, and when the substrate is a Fresnel lens, the at least one electrode pattern follows a continuous spiral pattern.

8. An optical element, a pair of optically transparent substrates including a first substrate and a second substrate; an active substance encapsulated between the first substrate and the second substrate; a set of electrode patterns deposited on a first surface of the active material; and - any electrode pattern belonging to the set of electrode patterns is deposited on the first substrate; - each electrode pattern in the set of electrode patterns has a pair of end terminals; - any electrode pattern belonging to said set of electrode patterns constitutes a set of segments; - every segment in the set of segments is associated with one of the resistors in the set of resistors; the set of resistors allows application of the voltage distribution along the radial or optical axis of the active material when a set of drive voltages is supplied to the pair of end terminals of the electrode patterns belonging to the set of electrode patterns; application of said voltage distribution results in a change in the refractive index of said active material; Optical elements.

9. 9. The optical element of claim 8, wherein the change in refractive index corresponds to a refractive index profile that indicates a first change in refractive index difference along a radial or optical axis of the active material, and the voltage distribution is determined based on the refractive index profile and a second change in refractive index of the active material in response to a voltage applied to the active material.

10. 10. The optical element of claim 8 or 9, wherein the set of resistors corresponds to a set of resistance values.

11. 11. An optical element according to claim 8, wherein each of the segments of a set of segments of each electrode pattern of the set of electrode patterns is associated with one of the resistors of the set of resistors, and the resistance value of each resistor of the set of resistors is controlled based on at least one of varying the thickness or width of the associated segment or patterning the associated segment with holes.

12. 12. The optical element according to claim 8, wherein the set of drive voltages includes a first drive voltage and a second drive voltage, and the first drive voltage is supplied to a first end terminal of a pair of end terminals of each of the electrode patterns belonging to the set of electrode patterns, and the second drive voltage is supplied to a second end terminal of the pair of end terminals of each of the electrode patterns belonging to the set of electrode patterns.

13. the set of electrode patterns includes only a single electrode pattern; the first drive voltage is supplied to a first end terminal of the pair of end terminals, and the second drive voltage is supplied to a second end terminal of the pair of end terminals; 13. The optical element according to claim 8.

14. 13. An optical element according to claim 8, wherein a first end terminal of each electrode pattern of the set of electrode patterns is coupled to a first segment of a set of segments constituting the electrode pattern, and a second end terminal of each electrode pattern of the set of electrode patterns is coupled to a second segment of the set of segments constituting the electrode pattern.

15. 14. The optical element of claim 9, wherein the first substrate is a plano-convex lens, a plano-concave lens, or a Fresnel lens, and when the first substrate is a Fresnel lens, each electrode pattern of the set of electrode patterns follows a continuous spiral pattern, and each electrode pattern of the set of electrode patterns is associated with one of a set of Fresnel zones.

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