Abstract: An optical system for displaying an image to a viewer includes a partial reflector, a reflective polarizer, and a first retarder layer. A light ray propagates along the optical axis and passes through the plurality of optical lenses, the partial reflector, the reflective polarizer, and the first retarder layer without being substantially refracted. For a cone of light incident on the optical system from an object comprising a spatial frequency of about 70, 60, 50, 40, or 30 line pairs per millimeter and filling the exit pupil with a chief ray of the cone of light passing through a center of the opening of the exit pupil of the optical system and making an angle of about 20 degrees with the optical axis, a modulation transfer function of the optical system is greater than about 0.2.

Abstract: A portable sensor for measuring a hydration level of an object in close physical proximity with the sensor includes a portable housing having a total volume of less than about 50 cm3. First circuitry disposed in the housing includes a thermal source, a controller electrically coupled to the thermal source, a temperature sensing element, and a processor coupled to the temperature sensing element. When the object is in close physical proximity with the sensor, the thermal source is energized by the controller with a signal having a known function of time. The object affects a time variation of a temperature of the thermal source, the temperature sensing element senses the affected time variation of the temperature of the thermal source, and the processor determines a hydration level of the object based on a characteristic of the affected time variation of the temperature of the thermal source.

Abstract: A display system including an imager for forming an image, and a projection lens system for projecting the image formed by the imager is described. For each pixel in the plurality of pixels, the imager is configured to emit a cone of light having a central ray having a direction that varies with location of the pixel in the imager. The variation may increase a brightness of an image projected through the projection lens system by at least 30 percent. The display system may include a light guide having a light insertion portion adapted to receive light; a light transport portion disposed to receive light from the light insertion portion; and a light extraction portion disposed to receive light from the light transport portion.

Abstract: An image combiner, also referred to as a combiner optic, of a near-eye display system or the like transmits enough light so a user can see remote objects in a “world view”, while also reflecting enough light so the user can simultaneously see a projected image in a “projected” (augmented) view. The disclosed image combiners use two partial reflectors configured to form a wedged reflective cavity. In the display system, light from an imaging device follows a path to the user's eye that includes three reflections in the wedged cavity. By using this capability of the wedged cavity, the combiner optic can have a substantially reduced thickness, and lower profile, than a combiner optic that uses only one partial reflector and only one reflection in the optical path.

Abstract: Optical systems including a partial reflector, a reflective polarizer, and a retarder disposed between the partial reflector and the reflective polarizer are described. The reflective polarizer is curved about two orthogonal axes and includes at least one layer that is substantially optically uniaxial at at least one location. The optical system is adapted to provide an adjustable focus.

Abstract: An optical stack includes first and second lenses, a partial reflector, a reflective polarizer, and a retarder. The reflective polarizer is curved about two orthogonal axes and includes at least one layer that is substantially optically uniaxial at at least one location. An optical system includes the optical stack disposed between an image surface and an exit surface. The optical system is configured such that substantially any chief ray transmitted from the image surface to the exit surface is first incident on the reflective polarizer at an angle of incidence less than 30 degrees.

Abstract: An optical system and a magnifying device including the optical system are described. The optical system includes a reflective polarizer, a partial reflector, and a retarder disposed between the reflective polarizer and the partial reflector. The reflective polarizer is curved about two orthogonal axes and includes at least one layer that is substantially optically uniaxial at at least one location.

Abstract: An optical system includes a reflective surface, a display adapted to emit image light toward the reflective surface, and a multilayer reflective polarizer disposed proximate the reflective surface. The multilayer reflective polarizer is curved about two orthogonal axes and includes at least one layer that is substantially optically uniaxial at at least one location. The image light is transmitted by the multilayer reflective polarizer after it is first reflected by the multilayer reflective polarizer. A head-mounted display includes a first optical system and a second optical system disposed proximate the first optical system.

Abstract: An image combiner, also referred to as a combiner optic, of a near-eye display system or the like transmits enough light so a user can see remote objects in a “world view”, while also reflecting enough light so the user can simultaneously see a projected image in a “projected” (augmented) view. The disclosed image combiners use two partial reflectors configured to form a wedged reflective cavity. In the display system, light from an imaging device follows a path to the user's eye that includes three reflections in the wedged cavity. By using this capability of the wedged cavity, the combiner optic can have a substantially reduced thickness, and lower profile, than a combiner optic that uses only one partial reflector and only one reflection in the optical path.

Abstract: Integral optical stacks and optical systems including the integral optical stack are described. The integral optical stack may include first and second lenses, a partial reflector, a reflective polarizer curved about two orthogonal axes, and a quarter wave retarder. The reflective polarizer is curved about two orthogonal axes and includes at least one layer that is substantially optically biaxial at at least one first location on the at least one layer away from an optical axis of the optical stack and substantially optically uniaxial at at least one second location away from the optical axis.

Abstract: An optical system and a magnifying device including the optical system are described. The optical system includes an exit pupil, a reflective polarizer proximate the exit pupil, a partial reflector disposed adjacent the reflective polarizer opposite the exit pupil, and a quarter wave retarder disposed between the reflective polarizer and the partial reflector. The reflective polarizer is curved about two orthogonal axes and the partial reflector is spaced apart from the reflective polarizer.

Abstract: Optical systems including a partial reflector, a reflective polarizer, and a quarter wave retarder disposed between the partial reflector and the reflective polarizer are described. The reflective polarizer is curved about two orthogonal axes and has at least one location having a radial distance r1 from an optical axis passing through an apex of the reflective polarizer and a displacement s1 from a plane perpendicular to the optical axis at an apex of the reflective polarizer, where s1/r1 is at least 0.1. The optical system is adapted to provide an adjustable dioptric correction.

Abstract: A head-mounted display including a first optical system is described. The first optical system includes a partial reflector and a multilayer reflective polarizer disposed adjacent to and spaced apart from the partial reflector. The multilayer reflective polarizer is curved about orthogonal first and second axes and includes at least one layer that is substantially optically uniaxial at at least one location. Each chief ray that passes through the first optical system is first incident on the multilayer reflective polarizer at an angle of incidence less than 30 degrees.

Abstract: A portable sensor for measuring a hydration level of an object in close physical proximity with the sensor includes a portable housing having a total volume of less than about 50 cm3. First circuitry disposed in the housing includes a thermal source, a controller electrically coupled to the thermal source, a temperature sensing element, and a processor coupled to the temperature sensing element. When the object is in close physical proximity with the sensor, the thermal source is energized by the controller with a signal having a known function of time. The object affects a time variation of a temperature of the thermal source, the temperature sensing element senses the affected time variation of the temperature of the thermal source, and the processor determines a hydration level of the object based on a characteristic of the affected time variation of the temperature of the thermal source.

Abstract: A method of coating film in a roll. A film is wound into a roll with gaps between the layers of the film in the roll. A fluid is forced through the roll such that the fluid deposits a coating on at least one side of the film.

Abstract: A head-mounted display system including a contact lens having a first region and a second region adjacent the first region, an eyewear lens having an inner surface facing the contact lens, and an illuminator configured to produce an imaged light output directed toward the inner surface of the eyewear lens. A first imaged light ray produced by the illuminator is incident on the inner surface and is reflected by the eyewear lens to the first region. The first region is configured to transmit the first imaged light ray, and the second region is configured to reflect or absorb a second imaged light ray produced by the illuminator and reflected from the eyewear lens. The eyewear lens is configured to transmit an ambient light ray to the second region and the second region is configured to transmit the ambient light ray.

Abstract: An optical system including at least a first lens, a partial reflector and a reflective polarizer is described. The optical system has an optical axis such that a light ray propagating along the optical axis passes through the first lens the partial reflector and the reflective polarizer without being substantially refracted. At least one major surface of the optical system is rotationally asymmetric about the optical axis. A major surface of the optical system may have a first portion defined by a first equation and a second portion adjacent the first portion defined by a different equation. The first lens may have a contoured edge adapted to be placed adjacent an eye of a viewer and substantially conform to the viewer's face.

Abstract: A polarizing beam splitting system is described. The polarizing beam splitting system may include first and second prisms where the volume of the first prism is no greater than half the volume of the second prism. The first prism includes first and second surfaces and a light source may be disposed adjacent the first surface and an image forming device may be disposed adjacent the second surface. The first prism has a first hypotenuse and the second prism has a second hypotenuse. A reflective polarizer is disposed between the first and second hypotenuses.

Abstract: Optical systems including an image surface and an exit surface are described. First second and third optical lenses, a partial reflector, a multilayer reflective polarizer and a retarder are disposed between the image surface and the exit surface. At least one location on at least one layer of the multilayer reflective polarizer is substantially uniaxially oriented. Each chief light ray that passes from the image surface to the exit surface is incident on the multilayer reflective polarizer with an angle of incidence less than about 30 degrees. The optical system may include a plurality of major surfaces disposed between the image surface and the exit surface where each major surface is convex toward the image surface and where at least six different major surfaces have six different convexities.

Abstract: A head-mounted display system including a contact lens having a first region and a second region adjacent the first region, an eyewear lens having an inner surface facing the contact lens, and an illuminator configured to produce an imaged light output directed toward the inner surface of the eyewear lens. A first imaged light ray produced by the illuminator is incident on the inner surface and is reflected by the eyewear lens to the first region. The first region is configured to transmit the first imaged light ray, and the second region is configured to reflect or absorb a second imaged light ray produced by the illuminator and reflected from the eyewear lens. The eyewear lens is configured to transmit an ambient light ray to the second region and the second region is configured to transmit the ambient light ray.