A tunable optical filter, includes a light source configured to emit optical radiation to a sample; an input optical element configured to receive optical radiation reflected from the sample; a liquid crystal cell comprising electrodes, the liquid crystal cell contacting the input optical element; an output optical element, contacting the liquid crystal cell; and a control unit adapted to apply a preset voltage to the liquid crystal cell via the electrodes; wherein the input optical element and the output optical element have a same first refractive index, wherein, when voltage is not applied to the liquid crystal cell, the first refractive index is greater than a second refractive index of the liquid crystal cell for a wavelength range of incident optical radiation, and wherein the input optical element, the liquid crystal cell and the output optical element are tilted at an angle to the incident optical radiation.

A camera includes an optical filter for a sensor array of the camera. The optical filter includes a plurality of liquid crystal layers switchable between a reflection state and a transmission state. Each liquid crystal layer is configured to block spectral light in a different spectral light sub-band and transmit spectral light outside of the spectral light sub-band in the reflection state, and to transmit spectral light in the spectral light sub-band in the transmission state. An active illuminator of the camera is configured to emit active light in a selected spectral light sub-band. One or more of the plurality of liquid crystal layers is switched from the transmission state to the reflection state to tune the optical filter to block spectral light in all but the selected spectral light sub-band. The sensors of the sensor array are addressed to measure spectral light in the selected spectral light sub-band.

A camera includes an optical filter for a sensor array of the camera. The optical filter includes a plurality of liquid crystal layers switchable between a reflection state and a transmission state. Each liquid crystal layer is configured to block spectral light in a different spectral light sub-band and transmit spectral light outside of the spectral light sub-band in the reflection state, and to transmit spectral light in the spectral light sub-band in the transmission state. An active illuminator of the camera is configured to emit active light in a selected spectral light sub-band. One or more of the plurality of liquid crystal layers is switched from the transmission state to the reflection state to tune the optical filter to block spectral light in all but the selected spectral light sub-band. The sensors of the sensor array are addressed to measure spectral light in the selected spectral light sub-band.

An optical filter for a camera is switchable between a reflection state and a transmission state. The optical filter includes a first plurality of liquid crystals configured to dynamically form cholesteric phase structures in the reflection state that block right-handed circularly polarized light in a spectral light sub-band and transmit light outside of the spectral light sub-band. The first plurality of liquid crystals dynamically forms a nematic phase arrangement in the transmission state that transmits light in the spectral light sub-band. The optical filter further includes a second plurality of liquid crystals configured to dynamically form cholesteric phase structures in the reflection state that block left-handed circularly polarized light in the spectral light sub-band and transmit light outside of the spectral light sub-band. The second plurality of liquid crystals dynamically form a nematic phase arrangement in the transmission state that transmits light in the spectral light sub-band.

An ocular optical system including an eyewear device and a tunable light attenuator is provided. The tunable light attenuator is disposed on a light path which the eyewear device is disposed on and includes a plurality of cholesteric liquid crystal layers, a plurality of electrode layers, and a controller. Each of the cholesteric liquid crystal layers is disposed between two of the electrode layers. The controller is electrically connected to the electrode layers and configured to adjust voltages applied to the electrode layers so as to operate the cholesteric liquid crystal layers in at least two steps of light attenuation for randomly polarized light with at least one of a blue band and an ultraviolet band.

A touch screen panel may include a liquid crystal, a first transparent electrode and a second transparent electrode provided at both sides of the liquid crystal, and a controller configured to transfer image data to the first transparent electrode and the second transparent electrode in a first mode and sense a touch of a user on at least one of the first transparent electrode and the second transparent electrode in a second mode.

A liquid-crystal based color switch for use with an image sensor having sub-diffraction-limited (SDL) pixels. The color switch may switch between a first mode where green light is passed (and blue and red light is blocked) and a second mode where blue and red light is passed (and green light is blocked). The color switch may include an achromatic switch (such as a liquid crystal switch) and retarder stack filter that are both sandwiched between a first and a second polarizer. The SDL pixels may be distributed so that green subpixels are never adjacent to other green subpixels in the same row or column, so that red subpixels are always adjacent to green subpixels in the same row or column, and so that blue subpixels are always adjacent to green subpixels in the same row or column.

An object of the present invention is to provide a decorative sheet exhibiting high lustrousness even when observed from a direction deviated from a specular reflection of illumination light, and a liquid crystal display device and an automobile interior material each using the decorative sheet. The object is achieved by a decorative sheet including a cholesteric liquid crystal layer having wavelength-selective reflectivity and satisfying Expression (1),

R[45,20](1)/R[45,20](2)5Expression (1).

A transparent display panel is provided, including a liquid crystal cell, a chromic material and a trigger component. The liquid crystal cell includes an array substrate and a first transparent substrate disposed opposite each other. A liquid crystal layer is arranged between the array substrate and the first transparent substrate. The chromic material is arranged at a side of the first transparent substrate away from the array substrate. The trigger component is connected to the chromic material for enabling the chromic material to perform a reversible change between a transparent state and a colored state.

A reflective display tile can be used in connection with a static or video display. The tile includes a transparent substrate having a front surface, a rear surface, and a peripheral edge surrounding the front and rear surfaces, an electrostatic shutter array disposed at the front surface of said substrate, a reflective medium disposed at the rear surface of the substrate, and drive electronics disposed rearward of the reflective medium. The shutter array and drive electronics are configured so that the tile is tileable and can be abutted at any of its peripheral edges against identical tiles to form a display with substantially no perceived optical interface between adjacent tiles. Another embodiment includes an opaque substrate such as a circuit board. A further embodiment has a polymeric film coated on one side with a metal film and on another side with ink or blackening material.