A form birefringent optical element includes a structured layer and a dielectric environment disposed over the structured layer. At least one of the structured layer and the dielectric environment includes a nanovoided polymer, the nanovoided polymer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Actuation of the nanovoided polymer can be used to reversibly control the form birefringence of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.

A pressure sensor and a pressure detecting method are provided, the pressure sensor includes a liquid crystal cell including a cholesteric liquid crystal layer, a liquid crystal state detector module and a pressure finder module, and the liquid crystal cell includes a pressure receiving surface. The liquid crystal state detector module is configured to detect a liquid crystal arrangement state in the cholesteric liquid crystal layer in a situation where a pressure is applied on the pressure receiving surface of the liquid crystal cell; the pressure finder module is configured to find a value of the pressure corresponding to the liquid crystal arrangement state from a pre-stored correspondence table.

A graded-index optical element may include a nanovoided material including a first surface and a second surface opposite the first surface. The nanovoided material may be transparent between the first surface and the second surface. Additionally, the nanovoided material may have a predefined change in effective refractive index in at least one axis due to a change in at least one of nanovoid size or nanovoid distribution along the at least one axis. Various other elements, devices, systems, materials, and methods are also disclosed.

A nanovoided polymer-based material may include a bulk polymer material defining a plurality of nanovoids and an interfacial film disposed at an interface between each of the plurality of nanovoids and the bulk polymer material. The interfacial film may include one or more layers of material. A method of forming a nanovoided polymer-based material may include (1) forming a bulk polymer material defining a plurality of nanovoids and (2) forming an interfacial film at an interface between each of the plurality of nanovoids and the bulk polymer material. Various other methods, systems, and materials are also disclosed.

A glass component of an electronic device housing may define a textured surface having micro-scale tactile friction features that provide a specified friction between a user's finger and the glass component. More specifically, the tactile friction features may reduce a contact surface area that is in contact with the user's finger in order to produce a reduced or specified coefficient of friction.

In some examples, a method includes forming a material layer on a substrate, partially polymerizing a component of the material layer, to form fluid-filled droplets within a partially polymerized matrix, deforming the material layer to form anisotropic fluid-filled droplets, and further polymerizing the partially polymerized matrix to form an anisotropic voided polymer, including anisotropic voids in a polymer matrix. The anisotropic voids may include anisotropic nanovoids. Example methods may further include depositing electrodes on the anisotropic voided polymer so that at least a portion of the anisotropic voided polymer is located between the electrodes. Examples may include forming electroactive elements including an anisotropic nanovoided polymer, and devices (such as sensors and/or actuators) including electroactive elements.

In some examples, a device includes a multilayer structure, a first electrode, and a second electrode, where the multilayer structure is located at least in part between the first electrode and the second electrode, and the multilayer structure includes a nanovoided polymer layer, and a solid layer. The solid layer may include a non-nanovoided layer. The nanovoided polymer layer may be an electroactive layer. The device may further include a control circuit configured to apply an electrical potential between the first electrode and the second electrode, which may induce a mechanical deformation of the multilayer.

An example device includes a nanovoided polymer element, a first electrode, and a second electrode. The nanovoided polymer element may be located at least in part between the first electrode and the second electrode. In some examples, the nanovoided polymer element may include anisotropic voids. In some examples, anisotropic voids may be elongated along one or more directions. In some examples, the anisotropic voids are configured so that a polymer wall thickness between neighboring voids is generally uniform. Example devices may include a spatially addressable electroactive device, such as an actuator or a sensor, and/or may include an optical element. A nanovoided polymer layer may include one or more polymer components, such as an electroactive polymer.

The invention provides composite materials comprising a shape change element and an optical change element, which elements undergo a change in response to an applied stimulus. Also provided are objects that include the subject shape changing materials, as well as methods of making and using the same.

Embodiments of the disclosure are generally directed to systems and methods for switchable electroactive devices for head-mounted displays (HMDs). In particular, a method may include (1) applying an electric field to an electroactive element of an electroactive device via electrodes of the electroactive device that are electrically coupled to the electroactive element to compress the electroactive element, which comprises a polymer material defining nanovoids, such that an average size of the nanovoids is decreased and a density of the nanovoids is increased in the electroactive element, wherein the electroactive device is positioned at a distance from a user's eye, and (2) emitting image light from an emissive device positioned such that at least a portion of the image light is incident on a surface of the electroactive device facing the user's eye.