Abstract: Methods for producing phosphor based light sources are disclosed. One method includes measuring an excitation light output of an LED, forming a plurality of phosphor film articles, measuring an optical characteristic of each of the plurality of phosphor film articles, selecting one of the plurality of phosphor film articles based on the LED excitation light output and measured optical characteristic of the one of the plurality of phosphor film articles to obtain a desired emission light output from the phosphor film article when the phosphor film article is positioned to receive the excitation light, and positioning the phosphor film article to receive the excitation light.

Abstract: An illumination system including a light source, a light guide including an output surface, emissive material positioned between the light source and the output surface of the light guide, and an interference reflector positioned between the emissive material and the output surface of the light guide is disclosed. The light source emits light having a first optical characteristic. The emissive material emits light having a second optical characteristic when illuminated with light having the first optical characteristic. The interference reflector substantially transmits light having the second optical characteristic and substantially reflects light having the first optical characteristic.

Abstract: A retroreflective article having at least one valve is disclosed. Each valve may include a channel extending from a first major surface to a second major surface of the retroreflective material, and at least one movable member proximate the channel. The at least one movable member is movable between a closed position and an open position. When in the closed position, the at least one movable member obstructs at least a portion of the channel. A method of making a retroreflective article having at least one valve is also disclosed.

Abstract: An illumination system including a light source, a light guide including an output surface, emissive material positioned to receive light from the output surface of the light guide, and a first interference reflector positioned between the output surface of the light guide and the emissive material is disclosed. The light source emits light having a first optical characteristic. The emissive material emits light having a second optical characteristic when illuminated with light having the first optical characteristic. The first interference reflector substantially transmits light having the first optical characteristic and substantially reflects light having the second optical characteristic.

Abstract: An illumination system including a light source, a light guide including an output surface, emissive material positioned to receive light from the output surface of the light guide, and an interference reflector positioned such that the emissive material is between the output surface of the light guide and the interference reflector is disclosed. The light source emits light having a first optical characteristic. The emissive material emits light having a second optical characteristic when illuminated with light having the first optical characteristic. The interference reflector substantially transmits light having the second optical characteristic and substantially reflects light having the first optical characteristic.

Abstract: An illumination system including a light source, light guides coupled to the light source, each including an input surface and an output surface, emissive material positioned to receive light from at least one light guide, and a first interference reflector positioned between the emissive material and the output surfaces of the light guides is disclosed. The light source emits light having a first optical characteristic. The emissive material emits light having a second optical characteristic when illuminated with light having the first optical characteristic. The first interference reflector substantially transmits light having the first optical characteristic and substantially reflects light having the second optical characteristic.

Abstract: A prismatic retroreflective article has a transparent body portion and a layer of internally reflecting cube-corner optical elements having an open air-exposed rear surface at least a portion of which is more hydrophobic, more oleophobic, or both more hydrophobic and more oleophobic than the underlying cube-corner optical element. The article may be made by providing a transparent body portion bearing a layer of internally reflecting open air-exposed cube-corner optical elements; treating or coating at least a portion of the cube-corner elements to make the treated or coated portion more hydrophobic, more oleophobic, or both more hydrophobic and more oleophobic than the underlying cube-corner optical elements; and leaving such treated or coated portion exposed to the open air.

Abstract: A retroreflective article 10 has a body portion 14 and a multitude of cube-corner elements 12 that project from a rear side 20 of the body portion 14. The body portion 14 includes a body layer 18 that contains a light-transmissible polymeric material having an elastic modulus less than 7×108 pascals. The cube-corner elements 12 contain a light transmissible polymeric material having an elastic modulus greater than 16×108 pascals. A retroreflective article of this construction can be highly flexed while maintaining good retroreflective performance.

Abstract: An illumination system including a light source, light guides coupled to the light source, each including an input surface and an output surface, emissive material positioned to receive light from at least one light guide, and an interference reflector positioned such that the emissive material is between the output surfaces of the light guides and the interference reflector is disclosed. The light source emits light having a first optical characteristic. The emissive material emits light having a second optical characteristic when illuminated with light having the first optical characteristic. The interference reflector substantially transmits light having the second optical characteristic and substantially reflects light having the first optical characteristic.

Abstract: An illumination system includes a plurality of radiation generating sources, such as LED dies. A corresponding plurality of optical waveguides is also provided, with each waveguide having a first and a second end, with each first end being in optical communication with the corresponding LED die. An array of corresponding passive optical elements is interposed between the plurality of LED dies and the corresponding first ends of the plurality of optical waveguides. The illumination system provides for substantially high light coupling efficiency and an incoherent light output that can appear to the human observer as arising from a single point of light. In addition, the light can be output remotely at one or more locations and in one or more directions.

Abstract: Optical devices such as backlight assemblies, according to the present invention include a multilayer optical film in which at least one of the layers comprises an oriented birefringent polymer. The multilayer optical film exhibits low absorptivity and can reflect light approaching at shallow angles as well as normal to the film.

Abstract: Color shifting retroreflective articles can provide features such as decorative effects, evidence of tampering, security authentication or positional information. In some embodiments, the color shifting retroreflective article includes a layer of microspheres, and a reflective coating that is disposed in optical association with the layer of microspheres. The reflective coating includes a spacer layer disposed between a semitransparent first reflective layer and a second reflective layer. The first reflective layer includes a reflective layer disposed adjacent the layer of microspheres. At least one layer of the reflective coating includes a non-uniform thickness associated with each of a plurality of microspheres such that light incident on the article from a first direction is retroreflected at a first color and light incident on the article from a second direction is retroreflected at a second color visibly different from the first color.

Abstract: Methods of applying a polymer coating to a substrate are disclosed. By disrupting a bank of polymer precursor, a smooth coating of fast setting polymer can be applied to a substrate. Apparatus for applying a polymer coating is also disclosed. In one embodiment, an oscillating dispenser is used to apply polymer precursor onto a dispersive surface. The polymer precursor flows down the surface and is transferred to a moving web. Flowing solvent downwardly through the dispenser can provide efficient cleaning without the need for disassembly or production delays.

Abstract: A lens having at least one lens centration mark formed on a major surface of the lens is disclosed. The lens centration mark may be located at the intersection of a first axis and the major surface, where the major surface is symmetrical about the first axis such that the first axis is an axis of revolution of the surface. A method of making a lens having such lens centration mark, as well as a method for measuring the centration of a lens surface utilizing the lens centration mark, are also disclosed.

Abstract: A continuous process for imparting a striking glittering or sparkling appearance to a roll of initially non-glittering cube corner sheeting includes exposing the sheeting to a combination of heat and pressure. The process includes passing the sheeting through an extended heated zone and applying pressure to the sheeting after it has been heated. At least one belt is employed to support or carry the sheeting as the sheeting is passed through the heated zone and as the pressure is applied. In one embodiment the sheeting is sandwiched between a pair of endless belts that pass through the extended heated zone, the nip, and a cooling zone downweb of the nip. The process is particularly advantageous for converting rolls of non-glittering cube corner sheeting into rolls of glittering cube corner sheeting.

Abstract: Methods of applying a polymer coating to a substrate are disclosed. By disrupting a bank of polymer precursor, a smooth coating of fast setting polymer can be applied to a substrate. Apparatus for applying a polymer coating is also disclosed. In one embodiment, an oscillating dispenser is used to apply polymer precursor onto to a dispersive surface. The polymer precursor flows down the surface and is transferred to a moving web. Flowing solvent downwardly through the dispenser can provide efficient cleaning without the need for disassembly or production delays.

Abstract: A process for making a retroreflective article that includes the steps of providing a device (tool or a mold) having a first structured surface; applying a reflective layer on the first structured surface resulting in a first adhesion value between the reflective layer and the first structured surface, the reflective layer having an exposed surface; applying a molding polymer to the exposed surface of the reflective layer resulting in a second adhesion value between the reflective layer and the molding polymer. The second adhesion value is higher than the first adhesion value. The device is separated from the molding polymer to yield a retroreflective article that has a second structured surface that is the reverse image of the first structured surface. The separation causes a transfer of the reflective layer from the first structured surface to the retroreflective article.