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 three (or more) polarizer arrangement is used to demonstrate a wide-angle variable-neutral-density (VND) filter that has both contrast uniformity and color uniformity. According to one embodiment, the outer polarizers effectively counter-rotate with respect to a fixed center polarizer as a means of compensating for transmission non-uniformity associated with geometrical polarization distortions experienced by off-normal rays. In particular, the achromatic compensation arrangement enables angle uniformity relative to normal-incidence transmission when the number of stops of attenuation grows large (e.g. 10-stops, or OD3). The filters are useful for cameras or instrumentation allowing mechanical or electromechanical tuning.

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: 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. They may be most appropriate for applications where light efficiency is not critical, such as well-lit environments, where the insertion-loss of 1 to 2 stops is not problematic.

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: 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: 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: 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: 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: A three (or more) polarizer arrangement is used to demonstrate a wide-angle variable-neutral-density (VND) filter that has both contrast uniformity and color uniformity. According to one embodiment, the outer polarizers effectively counter-rotate with respect to a fixed center polarizer as a means of compensating for transmission non-uniformity associated with geometrical polarization distortions experienced by off-normal rays. In particular, the achromatic compensation arrangement enables angle uniformity relative to normal-incidence transmission when the number of stops of attenuation grows large (e.g. 10-stops, or OD3). The filters are useful for cameras or instrumentation allowing mechanical or electromechanical tuning.

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: An electrodeless plasma lamp and a method of controlling operation of a plasma lamp are provided. The plasma lamp may a power source to provide radio frequency (RF) power and a lamp body to receive the RF power from a feed. The lamp body may comprise a dielectric material having a dielectric constant greater than 2 and bulb is provided that contains a fill that forms a plasma that emits light when at least a portion of the RF power is coupled to the fill. A light guide directs light from the bulb to a photosensor that is shielded from light output from a front side of the lamp body. The lamp includes a drive circuit to control operation of the lamp based on a level of light detected by the photosensor.

Abstract: A plasma lamp for an electrodeless plasma lamp having a dielectric waveguide body and a bulb positioned, at least in part, in the waveguide body and having at least one end protruding from the waveguide body. A probe is used to couple power into the waveguide body. The power resonates in the waveguide body and ignites a plasma in the bulb. By having one or both ends of the bulb extend beyond the surface of the waveguide body, the ends of the bulb are exposed to reduced electric field intensity, resulting in longer bulb lifetime due to reduced plasma impingement on the interior surfaces of the bulb.