Abstract: The disclosed computer-implemented method may include coupling an array of reflective polarizers to a back surface of a back optical substrate; coupling an array of quarter-wave plates to a front surface of the back optical substrate such that the array of quarter-wave plates is aligned with the array of reflective polarizers; molding the back optical substrate with at least one initial mold, wherein the at least one initial mold defines an initial array of optical element surfaces that is aligned with the array of quarter-wave plates; and twin-sheet thermoforming, between a front twin-sheet mold and a back twin-sheet mold, the back optical substrate with a front optical substrate, wherein the front twin-sheet mold defines a front array of optical element surfaces and the back mold defines a back array of optical element surfaces. Various other methods, apparatuses, and systems are also disclosed.

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: 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: 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 compound retarder that creates independent control of Re and Rth. This can be done by forming a three-layer compound retarder, including a pair of matched ?A-plates, combined with single +A-plate. The +A-plate is typically an MD-stretched film, with retardation that is specific to the in-plane requirements (Re) of the application. The pair of ?A-plates have their optic axes crossed, such that Re=0, with an optic axis aligned parallel to the +A-plate. A single retardation value for the ?A-plate can produce improved field-of-view performance over a broad range of Re values, making it a very practical means of universal compensation. While Rth is typically associated with a single retarder, retarder stacks with a diverse range of optic-axis orientations can be considered to have a compound (or composite) Rth value (Rthc). The three-layer compound retarder has the practical benefit of enabling field-of-view compensation across a broad range of normal-incidence polarization transformations.

Abstract: A laminator for high-precision solvent-bonding of retardation films is disclosed. The laminator is capable of producing laminates with high orientation repeatability and low in-plane stress which can otherwise create gaps between optimum theoretical performance and that which is physically realizable. Batch-mode laminators are scalable to large area mother-sheets and are suited to high-throughput manufacturing.

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 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: 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: A compound retarder that creates independent control of Re and Rth. This can be done by forming a three-layer compound retarder, including a pair of matched ?A-plates, combined with single +A-plate. The +A-plate is typically an MD-stretched film, with retardation that is specific to the in-plane requirements (Re) of the application. The pair of ?A-plates have their optic axes crossed, such that Re=0, with an optic axis aligned parallel to the +A-plate. A single retardation value for the ?A-plate can produce improved field-of-view performance over a broad range of Re values, making it a very practical means of universal compensation. While Rth is typically associated with a single retarder, retarder stacks with a diverse range of optic-axis orientations can be considered to have a compound (or composite) Rth value (Rthc). The three-layer compound retarder has the practical benefit of enabling field-of-view compensation across a broad range of normal-incidence polarization transformations.

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: A compound retarder that creates independent control of Re and Rth. This can be done by forming a three-layer compound retarder, including a pair of matched ?A-plates, combined with single +A-plate. The +A-plate is typically an MD-stretched film, with retardation that is specific to the in-plane requirements (Re) of the application. The pair of ?A-plates have their optic axes crossed, such that Re=0, with an optic axis aligned parallel to the +A-plate. A single retardation value for the ?A-plate can produce improved field-of-view performance over a broad range of Revalues, making it a very practical means of universal compensation. While Rthis typically associated with a single retarder, retarder stacks with a diverse range of optic-axis orientations can be considered to have a compound (or composite) Rth value (RthC). The three-layer compound retarder has the practical benefit of enabling field-of-view compensation across a broad range of normal-incidence polarization transformations.

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: 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 laminator for high-precision solvent-bonding of retardation films is disclosed. The laminator is capable of producing laminates with high orientation repeatability and low in-plane stress which can otherwise create gaps between optimum theoretical performance and that which is physically realizable. Batch-mode laminators are scalable to large area mother-sheets and are suited to high-throughput manufacturing.

Abstract: A polarization conversion system (PCS) is located in the output light path of a projector. The PCS may include a polarizing beam splitter, a polarization rotating element, a reflecting element, and a polarization switch. Typically, a projector outputs randomly-polarized light. This light is input to the PCS, in which the PCS separates p-polarized light and s-polarized light at the polarizing beam splitter. P-polarized light is directed toward the polarization switch on a first path. The s-polarized light is passed on a second path through the polarization rotating element (e.g., a half-wave plate), thereby transforming it to p-polarized light. A reflecting element directs the transformed polarized light (now p-polarized) along the second path toward the polarization switch. The first and second light paths are ultimately directed toward a projection screen to collectively form a brighter screen image in cinematic applications utilizing polarized light for three-dimensional viewing.

Abstract: Optical films that are thermo-formed to create a curved surface while maintaining a fixed magnitude and orientation of the local in-plane birefringence. While perhaps not practical to maintain the magnitude of the differences in index of refraction between three orthogonal axes in a material undergoing an arbitrary deformation, it is possible to maintain the difference between two of the indices under certain conditions. This enables the incorporation of functional retarder layers into curved structures such as lenses and reflective polarizer films. Furthermore, it enables the minimization of retardation induced in the surrounding initially isotropic substrates.

Abstract: A digital neutral density (DND) filter that provides rapid reconfiguration between discrete density states using electro-optic devices such as liquid-crystal cells. Each filter stage may be dedicated to binary switching between a high-transmission state (giving minimal loss) and one or more prescribed densities in a filtering state. The design prescription may “hard-wire” a stage to produce switching between an all-pass filter and a prescribed filter density. Design parameters can be used to assign specific densities to each stage. Multiple stages can be cascaded to provide a plurality of discrete density values. Such DND filters can sacrifice analog tunability in order to optimize uniformity in color and transmission over a wide range of incidence angles.