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. Conductive electrodes extend over the first and second sides of the electro-optical layer. The conductive electrodes include an array of excitation electrodes including parallel stripes of a transparent conductive material having gaps between the stripes of a gap width that is less than the layer thickness of the electro-optical layer. Control circuitry is coupled to apply respective control voltage waveforms to the excitation electrodes and to modify the control voltage waveforms applied to each of the excitation electrodes concurrently and independently so as to generate a phase modulation profile in the electro-optical layer.

Abstract: Adaptive spectacles (20) include a frame (23), including a front piece (24) and temples (26) connected to respective edges of the front piece. Right and left electrically tunable lenses (30) are mounted in the front piece. Communication circuitry (68) disposed in the frame is configured to communicate over a wireless link with a mobile computing device (32) in proximity to the adaptive spectacles. Control circuitry (64) disposed in the frame is configured to apply control voltage waveforms to the electrically tunable lenses in order to set a refractive property of the electrically tunable lenses and to modify the control voltage waveforms in response to a command received over the wireless link by the communication circuitry from the mobile computing device.

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: A method for presenting information includes receiving a specified digital value for display, assigning to a set of colors respective digital codes comprising respective binary values representing three primary color components of the colors, and encoding the specified digital value by combining at least four of the digital codes while selecting the colors such that none of the binary values is constant over all of the selected colors. A symbol is presented for imaging by a computing device, the symbol comprising at least four regions meeting at a common vertex and having the colors selected so as to encode the specified digital value using the respective digital codes.

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, 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 extend over the first and second sides of the electro-optical layer. The conductive electrodes include an array of excitation electrodes including parallel stripes of a transparent conductive material having gaps between the stripes of a gap width that is less than the layer thickness of the electro-optical layer. Control circuitry is coupled to apply respective control voltage waveforms to the excitation electrodes and to modify the control voltage waveforms applied to each of the excitation electrodes concurrently and independently so as to generate a phase modulation profile in the electro-optical layer.

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: A method for presenting information includes receiving a specified digital value for display, assigning to a set of colors respective digital codes comprising respective binary values representing three primary color components of the colors, and encoding the specified digital value by combining at least four of the digital codes while selecting the colors such that none of the binary values is constant over all of the selected colors.

Abstract: A method for distributing information includes producing a symbol to be overlaid on at least one primary image presented on a first display screen, the symbol encoding a specified digital value in a set of color elements having different, respective colors. A message is received from a client device containing an indication of the specified digital value decoded by the client device upon capturing and analyzing a secondary image of the first display screen. In response to the message, an item of information relating to the primary image is transmitted to the client device, for presentation on a second display screen associated with the client device.

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: Imaging apparatus (28) includes a mosaic image sensor (38), which is configured to capture and output a mosaic image comprising a matrix of pixels that is made up of multiple interleaved sub-matrices, each sub-matrix containing the pixels of a single respective color. Processing circuitry (32) is configured to process the pixels in each of one or more of the sub-matrices separately from the pixels in the other sub-matrices in order to identify in the mosaic image a graphical tag (22) that encodes a digital value in a machine-readable form.

Abstract: Apparatus for vision correction includes an electrically-tunable optical phase modulator (42, 44), which is configured to be mounted in proximity to an eye of a subject. Control circuitry (26) is configured to apply drive signals to the optical phase modulator so as to generate in the optical phase modulator a first phase modulation profile in a central zone (37) that intercepts a line of sight (32) of the eye and a second phase modulation profile, different from the first phase modulation profile, in a peripheral zone (39) extending peripherally around the central zone over at least 180° of arc. The first phase modulation profile is selected so as to enable clear vision by the eye in the central zone, while the second phase modulation profile is selected so as to blur light that is incident on the eye through the peripheral zone.

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: 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: 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: 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 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: Imaging apparatus (28) includes a mosaic image sensor (38), which is configured to capture and output a mosaic image comprising a matrix of pixels that is made up of multiple interleaved sub-matrices, each sub-matrix containing the pixels of a single respective color. Processing circuitry (32) is configured to process the pixels in each of one or more of the sub-matrices separately from the pixels in the other sub-matrices in order to identify in the mosaic image a graphical tag (22) that encodes a digital value in a machine-readable form.

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: A tangible medium having a machine-readable symbol printed thereon, such that the symbol encodes a specified digital value in a set of color elements having different, respective colors, to be identified in an image of the symbol as red, green, blue, cyan, magenta and yellow color elements, respectively. The symbol is produced by applying cyan, magenta and yellow pigments to a substrate so as to produce the color elements, such that the color elements exhibit certain red, green, and blue intensity characteristics when measured in an sRGB color space.