Abstract: Optical apparatus (38) includes an electro-optical layer (46), contained within a transparent envelope (43, 44) and having an effective local index of refraction at any given location that is determined by a voltage waveform applied across the electro-optical layer at the location. An array of excitation electrodes (50) is disposed over a surface of the transparent envelope. Control circuitry (42) is configured to apply voltage waveforms to the excitation electrodes so as to generate across at least a part of the active area of the electro-optical layer a phase modulation profile (60, 63, 64, 65, 66, 67, 70) comprising spatially alternating peaks (61) and troughs (62) separated by phase transitions chosen so as to emulate a Fresnel lens. The troughs have respective phase modulation depths that vary by at least one quarter wavelength at a nominal wavelength of 500 nm across at least the part of the active area of the electro-optical layer that emulates the Fresnel lens.

Abstract: Optical apparatus includes an electrically-tunable lens, including an electro-optical layer, having, for a given polarization of light incident on the layer, an effective local index of refraction at any given location within an active area of the electro-optical layer that is determined by a voltage waveform applied across the electro-optical layer at the location. Conductive electrodes extend over opposing first and second sides of the electro-optical layer and include an array of excitation electrodes. Control circuitry applies control voltage waveforms to the excitation electrodes. A polarization rotator is positioned and configured to intercept incoming light that is directed toward the lens and to rotate a polarization of the intercepted light so as to ensure that the light incident on the electro-optical layer has a component of the given polarization regardless of an initial linear polarization of the intercepted light.

Abstract: An optical device includes an electro-optical layer and conductive electrodes disposed over opposing first and second side of the electro-optical layer. Control circuitry is configured to apply at least first control voltage waveforms and second control voltage waveforms between the conductive electrodes so as to generate respective first and second phase modulation profiles in the electro-optical layer, which cause rays of optical radiation that are incident on the device to converge or diverge with respective first and second focal powers, and to change from the first focal power to the second focal power by concurrently applying overshoot control voltages to each of a plurality of the conductive electrodes for different, respective transition periods, followed by application of the second control voltage waveforms.

Abstract: An optical device includes an electro-optical layer, having an effective local index of refraction that is determined by a voltage waveform applied across the electro-optical layer at the location. A first array of first excitation electrodes extend along respective, mutually-parallel first axes in a first direction over the active area on a first side of the electro-optical layer. A second array of second excitation electrodes extend along respective, mutually-parallel second axes in a second direction, orthogonal to the first direction, over the active area on a second side of the electro-optical layer, opposite the first side. Control circuitry is coupled to apply respective control voltage waveforms to the excitation electrodes and is configured to concurrently modify the respective control voltage waveforms applied to both the first excitation electrodes and the second excitation electrodes so as to generate a specified phase modulation profile in the electro-optical layer.

Abstract: An augmented reality system (70, 100, 140, 180, 190) includes an augmented reality projector (72, 102, 142, 192) that is configured to project an image to an eye (82, 118, 154, 206) of an observer and to allow the observer to view a real scene (80, 116, 164, 204) through the projector. The system further includes first and second electrically-tunable dynamic lenses (74, 76, 104, 106, 144, 146, 194, 196), which are positioned respectively on opposing first and second sides of the projector, and a controller (78, 110, 150, 198) that is coupled to the projector and the first and second electrically-tunable dynamic lenses. The controller is configured to receive an adjustable accommodation parameter and a specified distance of interest and to set respective first and second refractive powers of the first and second dynamic lenses responsively to the adjustable accommodation parameter and the distance.

Abstract: An optical device (20) includes an electro-optical layer, including a liquid crystal material (24) with a heliconical structure having a pitch that is less than 250 nm and is modifiable by an electric field. An array of excitation electrodes (28) extends over the electro-optical layer. Control circuitry (23) is coupled to apply control voltage waveforms to the excitation electrodes and is configured to modify the control voltage waveforms so as to locally modify a molecule director angle of the heliconical structure and thus to generate a specified phase modulation profile in the electro-optical layer.

Abstract: A system for controlling at least one focus aspect of adaptive spectacles (10) having at least one electrically-tunable lens (22), the system including a housing (14), which is physically separate from adaptive spectacles (10), a display screen (16) mounted in housing (14), a sensor (19) mounted in housing (14) and configured to detect a relative position of adaptive spectacles (10) with respect to display screen (16), an interface (17) configured to communicate with adaptive spectacles (10), and a controller (15) configured to receive an input signal from sensor (19), the input signal being indicative of the relative position of adaptive spectacles (10) with respect to display screen (16) and output, in response to the input signal, a command signal for sending to adaptive spectacles (10) via interface (17) to adjust the at least one focus aspect of the at least one electrically-tunable lens (22).

Abstract: Optical apparatus (20) includes a transparent envelope (26) configured to be mounted in a spectacle frame. An electro-optical layer (46) is contained within the envelope, with an array of transparent excitation electrodes (50) disposed over a first surface of the transparent envelope. A transparent common electrode (52) is disposed over a second surface of the transparent envelope, opposite the first surface, and is electrically separated into a central region defining an active area (24) of the electro-optical layer and a peripheral region, which at least partially surrounds the central region. Control circuitry (72, 82, 92) holds the central region of the transparent common electrode at a predefined common voltage while allowing the peripheral region to float electrically, and to apply control voltage waveforms to the excitation electrodes, relative to the common voltage, so as to generate a specified phase modulation profile in the active area of the electro-optical layer.

Abstract: An optical device (20) includes an electro-optical layer, including a liquid crystal material (24) with a heliconical structure having a pitch that is less than 250 nm and is modifiable by an electric field. An array of excitation electrodes (28) extends over the electro-optical layer. Control circuitry (23) is coupled to apply control voltage waveforms to the excitation electrodes and is configured to modify the control voltage waveforms so as to locally modify a molecule director angle of the heliconical structure and thus to generate a specified phase modulation profile in the electro-optical layer.

Abstract: Adaptive spectacles (20) include a spectacle frame (25) and first and second electrically-tunable lenses (22, 24), mounted in the spectacle frame. In one embodiment, control circuitry (26) is configured to receive an input indicative of a distance from an eye of a person wearing the spectacles to an object (34) viewed by the person, and to tune the first and second lenses in response to the input.

Abstract: An optical device (40) includes an electro-optical layer (46), having an effective local index of refraction at any given location within an active area of the electro-optical layer that is determined by a voltage waveform applied across the electro-optical layer at the location. Conductive electrodes (50, 52) are disposed over opposing first and second side of the electro-optical layer. Control circuitry (26) is configured to apply control voltage waveforms between the conductive electrodes so as to generate a phase modulation profile in the electro-optical layer that causes rays of optical radiation that are incident on the device to converge or diverge with a given focal power, while varying an amplitude of the control voltage waveforms for the given focal power responsively to an angle of incidence of the rays that impinge on the device from a direction of interest.

Abstract: Optical apparatus includes a Fresnel lens (40), including an array of refractive bands (37) bordered by abrupt phase steps (39) of a height selected so as to focus light in different, first and second wavelength ranges from an object plane (35) toward an image plane (36) with a modulation transfer function (MTF) in excess of a predefined threshold, while focusing light in a third wavelength range, intermediate the first and second wavelength ranges, with MTF less than the predefined threshold. A display (32) is configured to generate, at the object plane of the Fresnel lens, an image including first and second pixel colors within the first and second wavelength ranges, respectively.

Abstract: An optical device (34, 66, 76) includes an electro-optical layer (48), having an effective local index of refraction at any given location within an active area of the electro-optical layer that is determined by a voltage waveform applied across the electro-optical layer at the location. Conductive electrodes (44, 64, 74, 82, 84) extend over opposing first and second sides of the electro-optical layer. The electrodes include an array of excitation electrodes, which extend along respective, mutually-parallel axes in a predefined direction across the first side of the electro-optical layer, and which includes at least first and second electrodes having different, respective widths in a transverse direction, perpendicular to the axes. Control circuitry (38) is coupled to apply respective control voltage waveforms to the excitation electrodes so as to generate a specified phase modulation profile in the electro-optical layer.

Abstract: Adaptive spectacles (20) include a spectacle frame (25) and first and second electrically-tunable lenses (22, 24), mounted in the spectacle frame. In one embodiment, control circuitry (26) is configured to receive an input indicative of a distance from an eye of a person wearing the spectacles to an object (34) viewed by the person, and to tune the first and second lenses in response to the input.

Abstract: An optical device includes an electro-optical layer, having an effective local index of refraction at any given location within an active area of the electro-optical layer that is determined by a voltage waveform applied across the electro-optical layer at the location. An array of excitation electrodes, including parallel conductive stripes extending over the active area is disposed over one or both sides of the electro-optical layer. Control circuitry is coupled to apply respective control voltage waveforms to the excitation electrodes and is configured to concurrently modify the respective control voltage waveforms applied to excitation electrodes so as to generate a specified phase modulation profile in the electro-optical layer.

Abstract: An optical device (24, 60) includes an electro-optical layer (40, 62), having an effective local index of refraction at any given location within an active area of the electro-optical layer that is determined by a voltage waveform applied across the electro-optical layer at the location. An array of excitation electrodes (46, 68, 72), including parallel conductive stripes extending over the active area is disposed over one or both sides of the electro-optical layer. Control circuitry (48, 70, 74) is coupled to apply respective control voltage waveforms to the excitation electrodes and is configured to concurrently modify the respective control voltage waveforms applied to excitation electrodes so as to generate a specified phase modulation profile in the electro-optical layer.