A shape memory alloy apparatus (1) comprising: a member (3) comprising a first end portion (5) and a second end portion (7); and a shape memory alloy component (9) connected to the member (3). The shape memory alloy component (9) being configured to, on contraction, change the separation between the first end portion (5) and the second end portion (7) of the member (3), the member (3) being configured to be in tension during contraction of the shape memory alloy component (9), wherein the said separation changes in a direction that is angled to the direction of contraction.

An optical element including a plate-shaped substrate with a light-entrance surface and a light-exit surface, a multiplicity of imaging elements formed on the light-exit surface and a multiplicity of diaphragms formed on the light-entrance surface. Each diaphragm includes a transparent geometric region in an opaque region. The optical element can be switched between two operating modes B1 and B2 such that some of the imaging elements change their focal length between values f1 and f2 and/or, some of the diaphragms change their aperture width and/or their position. Exactly one diaphragm is associated with each imaging element in mode B1 so that light passing through the diaphragm is imaged or collimated by the associated imaging element. Consequently, light arriving in the optical element through the diaphragms and then through the light-entrance surface has, after passing through the associated imaging elements in the two operating modes B1 and B2, different propagation angles.

Objective comprising a lens barrel, an actuator and a tunable lens, wherein the tunable lens comprises a primary membrane and a secondary membrane delimiting a liquid volume on opposing sides along an axial direction, the tunable lens comprises a container delimiting the liquid volume in lateral directions, wherein the lateral directions extend perpendicularly with respect to the axial direction, and the primary membrane and the secondary membrane are attached to opposing sides of the container, the tunable lens comprises a window member which is attached to the secondary membrane, wherein the secondary membrane connects the window member and the container elastically, wherein relative motion of the window member and the container along the axial direction results in a change of an optical property of the tunable lens, the window member or the container is fixedly attached to the lens barrel, the actuator is arranged to provide an actuation force along the axial direction, wherein the actuation force acts between the tunable lens and the lens barrel, and the actuation force results in a relative motion of the window member with respect to the container.

Objective comprising a lens barrel, an actuator and a tunable lens, wherein the tunable lens comprises a primary membrane and a secondary membrane delimiting a liquid volume on opposing sides along an axial direction, the tunable lens comprises a container delimiting the liquid volume in lateral directions, wherein the lateral directions extend perpendicularly with respect to the axial direction, and the primary membrane and the secondary membrane are attached to opposing sides of the container, the tunable lens comprises a window member which is attached to the secondary membrane, wherein the secondary membrane connects the window member and the container elastically, wherein relative motion of the window member and the container along the axial direction results in a change of an optical property of the tunable lens, the window member or the container is fixedly attached to the lens barrel, the actuator is arranged to provide an actuation force along the axial direction, wherein the actuation force acts between the tunable lens and the lens barrel, and the actuation force results in a relative motion of the window member with respect to the container.

A method includes depositing a surface modification layer on sidewalls of a plurality of cavities of a shaped article. The surface modification layer is formed from a glass material including a mobile component. The shaped article is formed from a glass material, a glass ceramic material, or a combination thereof. At least a portion of the mobile component is migrated from the surface modification layer into surface regions of the sidewalls of the shaped article, whereby subsequent to the migration, the surface regions have a reduced annealing point compared to a bulk of the shaped article. The surface modification layer and the surface regions of the sidewalls are reflowed. A surface roughness of the surface modification layer disposed on the sidewalls following the reflowing is less than a surface roughness of the sidewalls prior to the depositing.

A method of assembling an adjustable fluid-filled lens assembly comprising biaxially tensioning an elastomeric membrane to a surface tension of greater than 180 N/m, typically greater than 1000 N/m; thermally conditioning the tensioned membrane, e.g., for one hour at a temperature of about 80° C., to accelerate relaxation of the membrane; mounting the membrane to a peripheral support structure whilst maintaining the tension in the membrane; assembling the mounted membrane with one or more other components to form an enclosure with the membrane forming one wall of the enclosure; and thereafter filling the enclosure with a fluid. The membrane may be formed from an aromatic polyurethane, and the fluid may be a phenylated siloxane. In some embodiments, the membrane is able to hold a substantially constant surface tension of at least 180 N/m for a period of at least 12 months.

A method of assembling an adjustable fluid-filled lens assembly comprising biaxially tensioning an elastomeric membrane to a surface tension of greater than 180 N/m, typically greater than 1000 N/m; thermally conditioning the tensioned membrane, e.g., for one hour at a temperature of about 80° C., to accelerate relaxation of the membrane; mounting the membrane to a peripheral support structure whilst maintaining the tension in the membrane; assembling the mounted membrane with one or more other components to form an enclosure with the membrane forming one wall of the enclosure; and thereafter filling the enclosure with a fluid. The membrane may be formed from an aromatic polyurethane, and the fluid may be a phenylated siloxane. In some embodiments, the membrane is able to hold a substantially constant surface tension of at least 180 N/m for a period of at least 12 months.

A pancake lens assembly includes a partially reflective mirror, a reflective polarizer, a quarter waveplate, a polarization-dependent optical device, and at least one polarization controller. When a light beam is introduced into the pancake lens assembly along an optical axis in a Z direction to pass through the polarization controller in a first state, a polarization direction of the light beam is converted by the polarization controller. When the light beam is introduced into the pancake lens assembly along the optical axis to pass through the polarization controller in a second state, the polarization direction of the light beam is prevented from being converted by the polarization controller.

A pancake lens assembly includes a partially reflective mirror, a reflective polarizer, a quarter waveplate, a polarization-dependent optical device, and at least one polarization controller. When a light beam is introduced into the pancake lens assembly along an optical axis in a Z direction to pass through the polarization controller in a first state, a polarization direction of the light beam is converted by the polarization controller. When the light beam is introduced into the pancake lens assembly along the optical axis to pass through the polarization controller in a second state, the polarization direction of the light beam is prevented from being converted by the polarization controller.

An apparatus for electromagnetic characterisation of internal features of an object, including a lens for placement between a source of electromagnetic energy and the object, the lens being composed of a first material having a first permittivity with openings therein containing or configured to receive one or more second materials having respective second permittivities different to the first permittivity, the openings being configured such that, when the openings contain the one or more second materials, the lens has a graded refractive index wherein an electromagnetic wave generated by the source and incident upon a first surface of the lens as a spherical wave exits a second surface of the lens in contact with a receiving surface of the object substantially as a plane wave, and a refractive index of the lens at the second surface of the lens substantially matches a refractive index of the object at the receiving surface to increase penetration of the plane wave into the object.