Abstract: An optical film includes a plurality of first layers disposed on a plurality of second layers. For each angle of incidence in an incident angle range of 0-50 degrees, an optical transmittance of each of the optical film and the plurality of second layers versus wavelength includes a band edge disposed in a transition wavelength range separating a visible wavelength range where the optical film and the plurality of second layers have respective average optical transmittances Tv and Tv2 from an infrared wavelength range where the optical film and the plurality of second layers have respective average optical transmittances Ti and Ti2. Each of Tv and Tv2 is greater than about 30%. An average value of Tv2 is greater than an average value of Tv by at least 5%. An average value of Ti is less than an average value of Ti2 by at least 20%.

Abstract: An example article may include an optical filter and a multilayer stack adjacent the optical filter. The multilayer stack may include a plurality of layers. Each respective layer of the plurality layers may define a respective window edge of a plurality of window edges. The plurality of window edges may define an optical window configured to transmit light through the optical filter. At least a first respective window edge of the plurality of window edges may be stepped relative to at least a second respective window edge of the plurality of window edges.

Abstract: In some examples, a retroreflective article may include a retroreflective substrate, and an optical pattern embodied on the retroreflective substrate. The optical pattern may include a first optical sub-pattern and a second optical sub-pattern, wherein the optical pattern represents a set of information that is interpretable based on a combination of the first optical sub-pattern that is visible in a first light spectrum and the second optical sub-pattern that is visible in a second light spectrum. The first and second light spectra may be different.

Abstract: Retroreflecting articles are described. In particular, retroreflecting articles including retroreflecting layers and contrast reduction layers are described. The contrast reduction layer decreases the near infrared retroreflective efficiency of the retroreflecting substrate by more than 50%.

Abstract: An optical system (150) is disclosed and includes an optical sensor (154), a plurality of photosensitive pixels (178) disposed on the optical sensor, a wavelength-selective optical filter (158) in optical communication with the photosensitive pixels, the wavelength-selective optical filter being disposed remotely from the optical sensor, and a plurality of spatially-variant areas (220, 224, 228, 232) disposed in the optical filter, at least one area of the plurality of spatially-variant areas including a downconverter (400, 500).

Abstract: Example systems may include one or both of a light emitter and a light receiver, and an optical filter. The optical filter may include a wavelength selective scattering layer configured to scatter visible light. The optical filter may include a wavelength selective reflecting layer having a predetermined transmission band configured to compensate for a color deviation. The optical filter may include a broadband reflecting layer having a predetermined reflection band configured to compensate for a color deviation. The optical filter may include a low-index layer configured to reduce a color deviation in light emitted by the light emitter or received by the light receiver. The wavelength selective scattering layer may include nanoparticles dispersed in a binder, wherein the ratio of the nanoparticles to the binder by weight is at least 50%. Example articles may include example optical filters.

Abstract: Optical constructions are disclosed. A disclosed optical construction includes a reflective polarizer layer, and an optical film that is disposed on the reflective polarizer layer. The optical film has an optical haze that is not less than about 50%. Substantial portions of each two neighboring major surfaces in the optical construction are in physical contact with each other. The optical construction has an axial luminance gain that is not less than about 1.2.

Abstract: An example optical filter may include an angle blocking layer having a first angular light blocking range ?AL relative to a normal axis, and an interference filter adjacent the angle blocking layer having a second angular light blocking range ?IF relative to the normal axis. ?IF and ?AL at least partially overlap. The example optical filter has a predetermined light transmission zone comprising angles from 0° to a maximum light transmission angle ?Tmax relative to a normal axis of the major surface. The example optical filter has a predetermined angular light blocking zone ?B, a union of ?IF and ?AL. An example optical filter may include an interference filter having an incidence angle-dependent reflection band and an absorbing layer having an absorption band. The incidence angle-dependent reflection band and the absorption band may overlap at at least one wavelength at at least one angle of incidence.

Abstract: An optical element includes a porous layer with a network of a plurality of interconnected voids. The porous layer is optically diffusive to at least one wavelength of light when the network of interconnected voids is substantially free of fluid. The porous layer of the optical element undergoes a detectable optical change upon fluid ingress into the network or egress from the network of interconnected voids.

Abstract: An optical system including a lighting component and a switchable diffuser in optical communication with the lighting component. The optical system may further include a low absorbing optical component. At least one outer surface of the switchable diffuser and/or the low absorbing optical component includes light redirecting structures. When the switchable diffuser is in a first state and the optical system produces a light output, the light redirecting structures are configured to increase the full width at half-maximum (FWHM) of the light output of the optical system in at least one direction by at least 5 degrees relative to that of an otherwise equivalent optical system that does not include the light redirecting structures.

Abstract: An example optical filter may include an angle blocking layer Slaving a first angular light blocking range ?AL relative to a normal axis, and an interference filter adjacent the angle blocking layer having a second angular light blocking range ?IF relative to the normal axis. ?IF and ?AL at least partially overlap. The example optical filter has a predetermined light transmission zone comprising angles from 0° to a maximum light transmission angle ?Tmax relative to a normal axis of the major surface. The example optical filter has a predetermined angular light blocking zone ?B, a union of ?IF and ?AL. An example optical filter may include an interference filter having an incidence angle-dependent reflection band and an absorbing layer having an absorption band. The incidence angle-dependent reflection band and the absorption band may overlap at least one wavelength at least one angle of incidence.

Abstract: A method of optimizing a plurality of control signals used in operating a vehicle is described. The operation has a plurality of associated measurable parameters. The method includes: for each control signal, selecting a plurality of potential optimum values from a predetermined set; operating the vehicle in at least a first sequence of operation iterations, where for each pair of sequential first and second operation iterations in the first sequence of operation iterations, the potential optimum value of one control signal in the first operation iteration is replaced in the second operation iteration with a next potential optimum value of the control signal, while the potential optimum values of the remaining control signals are maintained; for each operation iteration, measuring each parameter in the plurality of measurable parameters; and generating confidence intervals for the control signals to determine causal relationships between the control signals and the measurable parameters.

Abstract: A nanostructured article includes a substrate; a plurality of first nanostructures disposed on, and extending away from, the substrate; and a covalently crosslinked fluorinated polymeric layer disposed on the plurality of first nanostructures. The plurality of first nanostructures includes polyurethane. The polymeric layer at least partially fills spaces between the first nanostructures to an average minimum height above the substrate of at least 30 nm such that the polymeric layer has a nanostructured surface defined by, and facing away from, the plurality of first nanostructures.

Abstract: An optical device is disclosed and includes an optical sensor, a plurality of photosensitive pixels disposed on the optical sensor, a wavelength-selective optical filter in optical communication with the photosensitive pixels, and a plurality of spatially-variant written regions disposed in the optical filter, the written regions having a transmission spectrum and each of the written regions being larger than each of the pixels.

Abstract: Systems, assemblies, and methods for detecting changes in polarization states are described. Example systems may include a light receiving unit including a sensor and a receiving polarizer. The sensor is configured to sense light from a polarized light source deflected through the receiving polarizer by a light directing article. The sensor is configured to generate a signal indicative a received polarization state of light deflected by the light directing articles. Such systems may be coupled to vehicles and may be useful for sensor-detectable signs, indicia, and markings to facilitate automated or assisted vehicular transport.

Abstract: In some examples, a system includes: at least one light capture device; an article of personal protective equipment (PPE) that includes a plurality of retroreflective elements embodied on a surface of the article of PPE in a spatially defined arrangement, each retroreflective element of the plurality of retroreflective elements having at least two different retroreflective properties; a computing device communicatively coupled to the at least one light capture device, wherein the computing device is configured to: receive, from the at least one light capture device, retroreflected light that indicates at least two different retroreflective properties of at least one retroreflective element of the plurality of retroreflective elements; determine, based at least in part on each of the at least two different retroreflective properties, a safety event; and perform at least one operation based at least in part on the safety event.

Abstract: An optical system is disclosed and includes an optical sensor, a plurality of photosensitive pixels disposed on the optical sensor, a wavelength-selective optical filter in optical communication with the photosensitive pixels, the wavelength-selective optical filter being disposed remotely from the optical sensor, an area disposed in the wavelength-selective optical filter, the area having a transmission spectrum different from a transmission spectrum of a portion of the wavelength-selective optical filter not in the area and a reflector, the wavelength-selective optical filter and a measurement subject each being disposed between the reflector and the optical sensor along an optical path.

Abstract: A system may include one or both of a light emitter and a light receiver, and an optical filter. The optical filter includes a wavelength selective scattering layer. The wavelength selective scattering layer may have a near-infrared scattering ratio of less than about 0.9. The filter may have a visible reflective haze ratio of greater than about 0.5. A method may include disposing the wavelength selective scattering layer adjacent one or both of the light emitter and the light receiver. The optical filter may include a wavelength selective reflective layer. The optical filter may include a wavelength selective absorbing layer. An article may include the optical filter. The wavelength selective scattering layer may have an average near-infrared scattering of less than 60%, an average visible scattering of greater than 10%, and a difference between the % total visible reflectance and the % diffuse visible reflectance of less than 20.

Abstract: The disclosed patterned wavelength-selective material and process for making the patterned wavelength-selective material uses patterned applied adhesive and a structurally weak wavelength-selective material that includes portions that contact the adhesive and break to remain in contact with the adhesive. In one embodiment, the wavelength-selective material comprises an array of sections with cuts at least partially through a wavelength-selective film at each section secured to the adhesive. In another embodiment, the wavelength-selective film comprises a transfer stack of layers.

Abstract: Retroreflecting articles are described. In particular, retroreflecting articles including a quarter wave retarder and a retroreflecting layer are described. The retarder is rotationally invariant and the retroreflecting layer is non-depolarizing. Such articles may be useful for sensor-detectable signs, labels, and garments.