Abstract: A method of fabricating a lens element for an adjustable power lens of the kind comprising two lens elements that are slidable relative to one other in a direction transverse the optical axis of the lens and have respective lens surfaces that are shaped to act together to form a corrective lens, the power of which varies according to the relative disposition of the two lens elements, the method comprising the steps of forming a lens puck having two opposite faces, which are shaped to form opposite lens surfaces of one of the lens elements of the adjustable power lens, the puck having at least one alignment feature, and thereafter edging the puck to a desired eye shape with reference to the alignment feature.

Abstract: A method of fabricating a lens element for an adjustable power lens of the kind comprising two lens elements that are slidable relative to one other in a direction transverse the optical axis of the lens and have respective lens surfaces that are shaped to act together to form a corrective lens, the power of which varies according to the relative disposition of the two lens elements, the method comprising the steps of forming a lens puck having two opposite faces, which are shaped to form opposite lens surfaces of one of the lens elements of the adjustable power lens, the puck having at least one alignment feature, and thereafter edging the puck to a desired eye shape with reference to the alignment feature.

Abstract: An augmented reality display unit for use in an augmented reality headset or the like comprising front and rear variable focusing power compression liquid lens assemblies (220, 230) in mutual optical alignment on an optical axis (O), a transparent waveguide display (240) interposed between the front and rear liquid lens assemblies (220, 230) and a selectively operable adjustment mechanism for adjusting the focusing powers of the front and rear compression liquid lens assemblies (220, 230); wherein each of the front and rear compression liquid lens assemblies (220, 230) comprises a fluid-filled envelope (225, 235) having a first wall formed by a distensible elastic membrane (226, 236) that is held under tension around its edge by a peripheral support ring, a second substantially rigid wall (223, 233) formed by or supported on an inner surface of a transparent plate or a hard lens of fixed focusing power, and a collapsible side wall (227, 237), the membrane forming an optical surface of variable optical power,

Abstract: A method of fabricating a lens element for an adjustable power lens of the kind comprising two lens elements that are slidable relative to one other in a direction transverse the optical axis of the lens and have respective lens surfaces that are shaped to act together to form a corrective lens, the power of which varies according to the relative disposition of the two lens elements, the method comprising the steps of forming a lens puck having two opposite faces, which are shaped to form opposite lens surfaces of one of the lens elements of the adjustable power lens, the puck having at least one alignment feature, and thereafter edging the puck to a desired eye shape with reference to the alignment feature.

Abstract: A method of fabricating a lens element for an adjustable power lens of the kind comprising two lens elements that are slidable relative to one other in a direction transverse the optical axis of the lens and have respective lens surfaces that are shaped to act together to form a corrective lens, the power of which varies according to the relative disposition of the two lens elements, the method comprising the steps of forming a lens puck having two opposite faces, which are shaped to form opposite lens surfaces of one of the lens elements of the adjustable power lens, the puck having at least one alignment feature, and thereafter edging the puck to a desired eye shape with reference to the alignment feature.

Abstract: An augmented reality display unit for use in an augmented reality headset or the like comprising front and rear variable focusing power compression liquid lens assemblies (220, 230) in mutual optical alignment on an optical axis (O), a transparent waveguide display (240) interposed between the front and rear liquid lens assemblies (220, 230) and a selectively operable adjustment mechanism for adjusting the focusing powers of the front and rear compression liquid lens assemblies (220, 230); wherein each of the front and rear compression liquid lens assemblies (220, 230) comprises a fluid-filled envelope (225, 235) having a first wall formed by a distensible elastic membrane (226, 236) that is held under tension around its edge by a peripheral support ring, a second substantially rigid wall (223, 233) formed by or supported on an inner surface of a transparent plate or a hard lens of fixed focusing power, and a collapsible side wall (227, 237), the membrane forming an optical surface of variable optical power,

Abstract: A deformable membrane assembly comprises an at least partially flexible fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a resiliently bendable supporting ring, a fixed support for the envelope and selectively operable means for causing relative movement between the supporting ring and the support for adjusting the pressure of the fluid in the envelope, thereby to cause the membrane to deform. The bending stiffness of the ring varies round the ring such that upon deformation of the membrane the ring bends variably to control the shape of the membrane to a predefined form. The moving means comprise a plurality of ring-engaging members that are arranged to apply a force to the ring at spaced control points.

Abstract: A method of fabricating a lens element for an adjustable power lens of the kind comprising two lens elements that are slidable relative to one other in a direction transverse the optical axis of the lens and have respective lens surfaces that are shaped to act together to form a corrective lens, the power of which varies according to the relative disposition of the two lens elements, the method comprising the steps of forming a lens puck having two opposite faces, which are shaped to form opposite lens surfaces of one of the lens elements of the adjustable power lens, the puck having at least one alignment feature, and thereafter edging the puck to a desired eye shape with reference to the alignment feature.

Abstract: A deformable membrane assembly comprises an at least partially flexible fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a resiliently bendable supporting ring, a fixed support for the envelope and selectively operable means for causing relative movement between the supporting ring and the support for adjusting the pressure of the fluid in the envelope, thereby to cause the membrane to deform. The bending stiffness of the ring varies round the ring such that upon deformation of the membrane the ring bends variably to control the shape of the membrane to a predefined form. The moving means comprise a plurality of ring-engaging members that are arranged to apply a force to the ring at spaced control points.

Abstract: A deformable membrane assembly comprising a fixed support, a fluid-filled envelope, one wall of which is formed by an elastic membrane that is held under tension around its edge by a flexible membrane supporting member, the supporting member being coupled to the fixed support at a plurality of discrete control points around the supporting member by engaging members for controlling the position of the membrane edge; and an adjuster for adjusting the pressure of the fluid within the envelope to adjust the shape of the membrane; wherein at least three control points are provided that are situated around the membrane edge at spaced locations selected to increase the energy of the lowest order out-of-plane bending mode of the supporting member while allowing the membrane to deform according to one or more selected Zernike polynomials. An article of eyewear comprising such a deformable membrane assembly is also disclosed.

Abstract: An actuation mechanism for simultaneous actuation of first and second variable focal length lenses is disclosed. Each lens comprises a distensible membrane bounding a fluid-filled cavity, the focal length varying with the degree of curvature of the membrane as it distends. The actuation mechanism comprises a hydraulic master actuator in fluid communication with a hydraulic slave actuator associated with the first lens and with a hydraulic slave actuator associated with the second lens. Each slave actuator is configured to vary the degree of distension of the membrane of its associated lens in response to operation of the master actuator, whereby the master actuator is operable to cause a variation of the degree of distension of the membranes of both the first and second lenses simultaneously.

Abstract: An actuation mechanism for simultaneous actuation of first and second variable focal length lenses is disclosed. Each lens comprises a distensible membrane bounding a fluid-filled cavity, the focal length varying with the degree of curvature of the membrane as it distends. The actuation mechanism comprises a hydraulic master actuator in fluid communication with a hydraulic slave actuator associated with the first lens and with a hydraulic slave actuator associated with the second lens. Each slave actuator is configured to vary the degree of distension of the membrane of its associated lens in response to operation of the master actuator, whereby the master actuator is operable to cause a variation of the degree of distension of the membranes of both the first and second lenses simultaneously.

Abstract: A deformable membrane assembly comprises an at least partially flexible fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a resiliently bendable supporting ring, a fixed support for the envelope and selectively operable means for causing relative movement between the supporting ring and the support for adjusting the pressure of the fluid in the envelope, thereby to cause the membrane to deform. The bending stiffness of the ring varies round the ring such that upon deformation of the membrane the ring bends variably to control the shape of the membrane to a predefined form. The moving means comprise a plurality of ring-engaging members that we arranged to apply a force to the ring at spaced control points.

Abstract: An actuation mechanism for simultaneous actuation of first and second variable focal length lenses is disclosed. Each lens comprises a distensible membrane bounding a fluid-filled cavity, the focal length varying with the degree of curvature of the membrane as it distends. The actuation mechanism comprises a hydraulic master actuator in fluid communication with a hydraulic slave actuator associated with the first lens and with a hydraulic slave actuator associated with the second lens. Each slave actuator is configured to vary the degree of distension of the membrane of its associated lens in response to operation of the master actuator, whereby the master actuator is operable to cause a variation of the degree of distension of the membranes of both the first and second lenses simultaneously.

Abstract: The present invention provides a deformable membrane assembly 1 comprising an elastic membrane 8 that is held under tension around its edge by a bendable membrane supporting member 2,10, a body of fluid in contact with one face of the membrane, the pressure of the fluid being controllable for adjusting the shape of the membrane, and one or more bending controllers 24 acting on the supporting member 2, 10 to control the bending of the supporting member in response to loading through tension in the membrane. The bending stiffness of the membrane-supporting member 2, 10 varies round its extent to control the profile of the edge of the membrane 8; etc. upon actuation. A variety of different types of bending controllers are disclosed which permit out-of-plane bending of the supporting member 2, 10 but prevent or control in-plane bending or deformation of the supporting member.

Abstract: A deformable membrane assembly comprises an at least partially flexible fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a resiliently bendable supporting ring, a fixed support for the envelope and selectively operable means for causing relative movement between the supporting ring and the support for adjusting the pressure of the fluid in the envelope, thereby to cause the membrane to deform. The bending stiffness of the ring varies round the ring such that upon deformation of the membrane the ring bends variably to control the shape of the membrane to a predefined form. The moving means comprise a plurality of ring-engaging members that are arranged to apply a force to the ring at spaced control points.

Abstract: A deformable membrane assembly comprises an at least partially flexible fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a resiliently bendable supporting ring, a fixed support for the envelope and selectively operable means for causing relative movement between the supporting ring and the support for adjusting the pressure of the fluid in the envelope, thereby to cause the membrane to deform. The bending stiffness of the ring varies round the ring such that upon deformation of the membrane the ring bends variably to control the shape of the membrane to a predefined form. The moving means comprise a plurality of ring-engaging members that are arranged to apply a force to the ring at spaced control points.

Abstract: A deformable membrane assembly comprising a fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a bendable supporting ring, a support for the envelope and at least three ring-engaging members that are arranged to apply a force to the ring at spaced control points for adjusting the shape of the membrane, with the ring bending to control the shape of the membrane to a predefined form. A control point is provided at or proximate each point on the ring where the profile of the ring that is needed to produce the predefined form of the membrane exhibits a turning point in the direction of the force applied at the control point between two adjacent points where the profile of the ring exhibits an inflection point or a turning point in the opposite direction.

Abstract: A deformable membrane assembly comprising a fixed support, a fluid-filled envelope, one wall of which is formed by an elastic membrane that is held under tension around its edge by a flexible membrane supporting member, the supporting member being coupled to the fixed support at a plurality of discrete control points around the supporting member by engaging members for controlling the position of the membrane edge; and an adjuster for adjusting the pressure of the fluid within the envelope to adjust the shape of the membrane; wherein at least three control points are provided that are situated around the membrane edge at spaced locations selected to increase the energy of the lowest order out-of-plane bending mode of the supporting member while allowing the membrane to deform according to one or more selected Zernike polynomials. An article of eyewear comprising such a deformable membrane assembly is also disclosed.

Abstract: A method of manufacturing a variable focus fluid lens assembly which includes mounting a membrane assembly within a recess formed in a lens housing said assembly including a distensible transparent membrane supported round its periphery by a supporting member and a flexible tubular wall having first and second opposite ends one of said ends being joined to the supporting member to form a cavity within the wall that is closed at the one end by the membrane; filling the cavity with a transparent fluid and fitting a transparent cover plate to the housing across the other end of the wall. The other end being joined sealingly to the cover plate or to the housing thereby to seal the cavity to form a compressible fluid-filled envelope. The cover plate may include a fixed lens selected from a stock of lenses having the same shape for fitting to the lens assembly, but different other optical properties, such for example as different base curves and/or decentration distances.