Abstract: High-performance polarization-based triple-pass lenses require precise management of polarization over a range of incidence angles and wavelengths. These lenses have the potential to provide high optical power in a compact arrangement, as needed for (e.g.) wide field-of-view near-eye immersive display applications. Accordingly, disclosed herein is a wide-angle polarization-based triple-pass lens that includes an input polarizer producing a first transmitted linear polarization; a first retarder-stack for converting from linear-polarization to circular-polarization; a curved partial-reflector; a second retarder-stack for converting from circular-polarization to linear-polarization; a reflective linear-polarizer; and a geometric-compensator (GC) between the input polarizer and the first retarder-stack, the second quarter-wave retarder and the reflective linear-polarizer, or both. The GC reduces the first-pass transmission of the lens for rays incident off-normal.

Abstract: Optical filters that enhance image quality by exploiting differences in the wavelength dependence of the spectral power distribution (SPD) and the degree of polarization between elements in a scene in order to preserve, and more preferably enhance, color-contrast between one or more salient objects in the scene and/or a salient object and a background. The higher degree of polarization may be associated with the background or the one or more salient objects. Color contrast is associated with one or more of a difference in saturation, a difference in hue, and a difference in lightness.

Abstract: Single-stage polarization interference filters (PIFs) which produce sinusoidal transmission spectra useful for (Red, Green, Blue) color enhancement (CE). The depth of the CE effect can be modulated by rotating a polarizer. Further, a color suppression (CS) (Cyan/Yellow) state is obtained by rotating a polarizer to the orthogonal state, and a spectrally flat neutral state is obtained at an intermediate polarizer orientation. Described are CE filters that are very stable in transmitted lumens and white-point during tuning, which can, for example, substantially eliminate the need for image post-processing. Tunable CE filters can be used for sensors, image capture, display, tunable light sources, augmented reality, virtual reality, and sunglass eyewear applications. Further described are camera filters with a unique two-step tuning mechanism, which allows photographers to make independent adjustments to functional filter characteristics using a single hand in a sequential manner.

Abstract: In polarization-based optical systems, preserving a state-of-polarization (SOP) over a prescribed range of incidence angles and wavelengths may be necessary. Optical materials with local normal tilted with respect to an incident ray can introduce an undesirable polarization nonuniformity that can be substantially corrected using a compensator as disclosed herein. The compensator may include a uniaxial retarder and a z-partial polarizer (ZPP). The ZPP may include a uniaxial material with an absorption axis normal to the substrate.

Abstract: A polarization conversion system separates light from an unpolarized image source into a first state of polarization (SOP) and an orthogonal second SOP, and directs the polarized light on first and second light paths. The SOP of light on only one of the light paths is transformed to an orthogonal state such that both light paths have the same SOP. A polarization modulator temporally modulates the light on the first and second light paths to first and second output states of polarization. First and second projection lenses direct light on the first and second light paths toward a projection screen to form substantially overlapping polarization encoded images. The polarization modulator may be located before or after the projection lenses. The polarization-encoded images may be viewed using eyewear with appropriate polarization filters.

Abstract: Used herein are two or more switchable variable birefringence liquid crystal devices, in combination with a passive retarder, to produce a device that switches between two retardation values. The device preserves the normal-incidence retardation in each of two voltage states over a broad range of incidence angles using a novel self-compensation scheme. According to one embodiment of this design, the retardation in the thickness direction remains zero in both the unenergized and fully energized states.

Abstract: An imaging system that contains a display, a polarization folded path lens with an intended image signal path and an exit pupil wherein light entering the PFP lens from the display substantially follows the intended signal path. A variant of this system is disclosed where the light entering the PFP lens substantially follows the signal path and leaves via the Exit pupil (as opposed to being aperture). Compared to the prior art, the techniques described herein improve transmission efficiency and reduce corruption of the image by non-signal path light.

Abstract: Optical systems that can produce digitally switchable optical power, optical pathlength, or both. It can apply to reconfigurable wide-angle optical systems that are compact, light-weight, and light-efficient. Architectures that increase pathlength can utilize polarization splitters to produce an additional round-trip of one or more optical cavities. Changing the focus distance of synthetic imagery in augmented/virtual reality systems is an example of an application where the techniques taught herein are particularly well suited. Passive double-cavity systems can be used to increase the throughput and decrease the stray-light/ghosts in polarization-based compact wide-angle lenses.

Abstract: Polarization-based optical angle-filters disclosed herein can be engineered to transmit a prescribed amount of light as a function of incidence angle and azimuth. Such filters can transmit light without introducing artifacts, making them suitable for the image-path of an optical system. One example may include an angle-filter having an input circular polarizer, an analyzing circular polarizer, and a retarder positioned between the circular polarizers, the retarder having a thickness-direction retardation. The thickness-direction retardation of the retarder (Rth) is selected to produce a prescribed angle-of-incidence dependent transmission function, and the circular polarizers reduce the amount of azimuth-dependence in the transmission function.

Abstract: A direct view display provides a light modulating panel and a backlight including first and second sets of spectral emitters. Several modes of operation may be provided including an advanced 2D mode, and an enhanced color gamut mode employing simultaneous illumination of the first and second set of spectral emitters. Another embodiment may be an optical structure for a multi-functional LCD display with wide color gamut and high stereo contrast. The optical structure may also be used to produce more saturated colors for a wider display color gamut and also may be used to produce a brighter backlight structure through light recycling of the wider bandwidth light back into the optical structure.

Abstract: An eyewear lens is described that provides polarization filtering and spectral filtering using polarization interference. The lens produces enhanced saturation and colorfulness, increasing enjoyment when observing commonly encountered imagery. The lens can be configured to optimize accuracy/efficiency when performing a task involving colored imagery, and can improve performance in sports. The lens can further be helpful for color discrimination by those with certain types of color vision deficiency.

Abstract: An eyewear lens is described that provides polarization filtering and spectral filtering using polarization interference. The lens produces enhanced saturation and colorfulness, increasing enjoyment when observing commonly encountered imagery. The lens can be configured to optimize accuracy/efficiency when performing a task involving colored imagery, and can improve performance in sports. The lens can further be helpful for color discrimination by those with certain types of color vision deficiency.

Abstract: Used herein are two or more switchable variable birefringence liquid crystal devices, in combination with a passive retarder, to produce a device that switches between two retardation values. The device preserves the normal-incidence retardation in each of two voltage states over a broad range of incidence angles using a novel self-compensation scheme. According to one embodiment of this design, the retardation in the thickness direction remains zero in both the unenergized and fully energized states.

Abstract: A device for manipulating the polarization of light which includes a first retarder-stack (Stack 1) that converts the polarization of input light from a first polarization basis vector (PBV1) to a second polarization basis vector (PBV2), a second retarder-stack (Stack 2) that returns the polarization of light from PBV2 to PBV1, and one or more optically functional layers between Stack 1 and Stack 2. Stack 1 has a plurality of layers, wherein the number of layers, retardation values, and orientations of layers in Stack 1 are selected to produce a PBV2 that is substantially spectrally-uniform over a prescribed range of wavelengths. PBV1 is a non-trivial eigen-polarization of combined Stack 1 and Stack 2. Stack 2 has a plurality of layers and Stack 2 is arranged in series with Stack 1. Alternatively, instead of two different stacks, a reflector may be used to produce a return pass through Stack 1.

Abstract: Disclosed is a manufacturing method for a stepped imaging directional backlight apparatus which may include a structured optical film and a tapered body. The structured optical film may include multiple optical functions and may be assembled by folding onto the tapered body, reducing cost and complexity of manufacture.

Abstract: Hollow optical elements that derive optical power from compound-curved reflective surfaces to produce a desired composite optical power. The reflective surfaces in combination with polarization control, can produce a triple-pass arrangement that determines the optical power. Two functional films, one or both of which are formed (e.g., thermoformed), can be joined at the perimeter to form units that are mechanically robust and therefore preserve optical performance under mechanical load. The air-spaced cavity formed between the two layers is free of birefringence concerns, where polarization control is crucial to contrast. These optical elements can be installed in frames or headsets to form lightweight wearable magnifiers, wide-angle collimators, tele-photo lenses, or for any application requiring optical power.

Abstract: 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.

Abstract: A polarization conversion system separates light from an unpolarized image source into a first state of polarization (SOP) and an orthogonal second SOP, and directs the polarized light on first and second light paths. The SOP of light on only one of the light paths is transformed to an orthogonal state such that both light paths have the same SOP. A polarization modulator temporally modulates the light on the first and second light paths to first and second output states of polarization. First and second projection lenses direct light on the first and second light paths toward a projection screen to form substantially overlapping polarization encoded images. The polarization modulator may be located before or after the projection lenses. The polarization-encoded images may be viewed using eyewear with appropriate polarization filters.

Abstract: A direct view display provides a light modulating panel and a backlight including first and second sets of spectral emitters. Several modes of operation may be provided including an advanced 2D mode, and an enhanced color gamut mode employing simultaneous illumination of the first and second set of spectral emitters. Another embodiment may be an optical structure for a multi-functional LCD display with wide color gamut and high stereo contrast. The optical structure may also be used to produce more saturated colors for a wider display color gamut and also may be used to produce a brighter backlight structure through light recycling of the wider bandwidth light back into the optical structure.

Abstract: A polarization conversion system separates light from an unpolarized image source into a first state of polarization (SOP) and an orthogonal second SOP, and directs the polarized light on first and second light paths. The SOP of light on only one of the light paths is transformed to an orthogonal state such that both light paths have the same SOP. A polarization modulator temporally modulates the light on the first and second light paths to first and second output states of polarization. First and second projection lenses direct light on the first and second light paths toward a projection screen to from substantially overlapping polarization encoded images. The polarization modulator may be located before or after the projection lenses. The polarization-encoded images may be viewed using eyewear with appropriate polarization filters.