Abstract: A gas sensing system measures a concentration of a gas sample having an absorption peak at a first wavelength. An emitter emits light having a spectrum that includes at least the first wavelength. A sensor detects at least some of the light emitted by the emitter. A porous scattering material is substantially transparent at the first wavelength and scatters at least some of the light. A surface of the porous scattering material opposing the emitter and the sensor has a depression. The emitter and the sensor are laterally and vertically separated by a separator filling the depression. The separator specularly or diffusively reflects the light emitted by the emitter.

Abstract: A structure and method of operating an optical step-up transformer are described. The optical step-up transformer has at least one photodiode and at least one photoreceiver. The photoreceiver receives light emitted from the photodiode and generates a voltage proportional to the number of series-connected photoreceivers. The photodiode and photoreceiver may be electrically isolated or may share a common anode or cathode. The voltage applied to the photodiode may be a DC or PWM signal.

Abstract: A compound of the formula (I): wherein each symbol is as defined in the DESCRIPTION. or a pharmaceutically acceptable salt thereof has a superior Notch signal transduction inhibitory action, and is useful for preventing or treating various diseases involving Notch signal transduction.

Abstract: The pcLED pixels in a phosphor-converted LED array each comprise an optical element on the light-emitting surface above the phosphor layer. In methods for making such pixelated LED arrays, a thin layer of a sacrificial phosphor carrier substrate is retained as the optical element on the output surface of the phosphor pixels upon completion of the fabrication process.

Abstract: A gas sensing system can allow a gas sample to permeate hollow spaces within a porous scattering material. The porous scattering material can be substantially transparent at an illumination wavelength. An emitter can illuminate the porous scattering material and the gas sample with light having a spectrum that includes the illumination wavelength. A sensor can detect a level of light that has traversed the porous scattering material. Using, for example, the Beer-Lambert Law, the system can determine a concentration of the gas material in the gas sample. The scattering can greatly increase an optical path length through the porous scattering material, compared with a linear dimension of the porous scattering material. The increased optical path length can allow a gas chamber to shrink in size, thereby decreasing a size of the gas sensing system without a corresponding decrease in a sensitivity and/or an accuracy of the system.

Abstract: Systems for apparatuses formed of light emitting devices. Solutions for controlling the off-state appearance of lighting system designs is disclosed. Thermochromic materials are selected in accordance with a desired off-state of an LED device. The thermochromic materials are applied to a structure that is in a light path of light emitted by the LED device. In the off-state the LED device produces a desired off-state colored appearance. When the LED device is in the on-state, the thermochromic materials heat up and become more and more transparent. The light emitted from the device in its on-state does not suffer from color shifting due to the presence of the thermochromic materials. Furthermore, light emitted from the LED device in its on-state does not suffer from attenuation due to the presence of the thermochromic materials. Techniques to select and position thermochromic materials in or around LED apparatuses are presented.

Abstract: A sensor system comprises an LED arranged to emit light and to detect a portion of the emitted light that is scattered or reflected back to the LED. A sensing method comprises detecting with an LED light emitted by the LED and scattered or reflected back to the LED and determining a change in voltage-current characteristics of the LED resulting from detection of the scattered or reflected light. The sensor system and the sensing method may be used, for example, to determine properties of particles in a fluid into which the LED emits light or to determine the presence or absence of an object located between the LED and a reflective or scattering surface.

Abstract: This specification discloses LED arrays comprising a grid structure that physically and optically isolates adjacent LEDs or groups of LEDs in the array from each other. The grid structure comprises an arrangement of walls defining cells. Individual LEDs or groups of LEDs in the array are positioned within different ones of the cells, separated from adjacent LEDs or groups of LEDs by the grid walls. This specification also discloses fabrication processes for such LED arrays. In these fabrication processes, the grid structure is formed as a separate monolithic structure. The LEDs or pcLEDs are arranged on and attached to a substrate (for example, a printed circuit board), after which the grid structure is attached to the substrate in registry with the arrangement of LEDs or pcLEDs.

Abstract: A distributed Bragg reflector (DBR) structure on a substrate includes a high refractive index layer comprising titanium oxide (TiO2) and a low refractive index layer having a high carbon region and at least one low carbon region that contacts the high refractive index layer. Multiple layers of the high refractive index layer and the low refractive index layer are stacked. Typically, the multiple layers of the high refractive index layer and the low refractive index layer are stacked to a thickness of less than 10 microns. Each of the respective layers of the high refractive index layer and the low refractive index layer have a thickness of less than 0.2 microns.

Abstract: An array of phosphor pixels is positioned on an array of semiconductor LED pixels with thermally curable adhesive between them. Selected LED pixels of the array are electrically activated; resulting heat cures the adhesive to attach the corresponding phosphor pixel to the activated LED pixel and to release the corresponding phosphor pixel from a carrier. Removal of the carrier removes unattached phosphor pixels, leaving behind phosphor pixels attached to the LED pixels that were activated. The process can be repeated for phosphor pixels of different colors.

Abstract: An array of phosphor pixels is positioned on an array of semiconductor LED pixels with thermally curable adhesive between them. Selected LED pixels of the array are electrically activated; resulting heat cures the adhesive to attach the corresponding phosphor pixel to the activated LED pixel and to release the corresponding phosphor pixel from a carrier. Removal of the carrier removes unattached phosphor pixels, leaving behind phosphor pixels attached to the LED pixels that were activated. The process can be repeated for phosphor pixels of different colors.

Abstract: In a gas sensing system, a light emitter can emit light through a gas sample toward a concave reflective surface. The reflective surface can redirect the emitted light to propagate through the gas sample toward a light sensor. Using, optionally, the Beer-Lambert Law, the system can determine a concentration of the gas material in the gas sample. By selecting a specified shape for the reflective surface, such as a complete or partial ellipsoid, and locating the light emitter and the light sensor in specified locations, such as at one or both foci of the ellipsoid, the gas sensing system can reduce variation in optical path length, from optical path to optical path, in the light that propagates from the light emitter, to the reflective surface, and to the light sensor. Reducing the variation in optical path length can improve an accuracy in determining the concentration of the gas material.

Abstract: A device including a phosphor layer having a plurality of holes or pockets arranged within the phosphor layer to reduce lateral light transmission. The phosphor layer can be sized and positioned to extend over a plurality of LED emitter pixels.

Abstract: Pixelated array light emitters are formed with closely-spaced pixels having ultra-smooth sidewalls. In methods for making such pixelated array light emitters, a converter layer of phosphor particles dispersed in a binder is disposed on a carrier, and then singulated by saw cuts or similar methods to form an array of phosphor pixels. The binder is fully cured prior to singulation of the converter layer. Further, the carrier is rigid rather than flexible. As a consequence of fully curing the binder and of using a rigid carrier to support the converter layer, singulation results in phosphor pixels having smooth side walls. The array of phosphor pixels is subsequently attached to a corresponding array of LEDs with an adhesive layer, separate from the binder used to form the converter layer. The pixel sidewalls may be formed with controlled morphology, for example at acute or obtuse angles with respect to the carrier.

Abstract: In a gas sensing system, an emitter emits light through a gas toward a concave reflective surface. The reflective surface reflects the light toward a sensor while light that passes through a porous scattering material is scattered. The surface of the reflective surface provides a diffusion of the light. A concentration of the gas is detected by the sensor. The scattering material may be permeable or non-permeable to the gas. The scattering and reflecting of the light increases the distance the light travels from the emitter to the sensor to increase absorption of the light by the gas.

Abstract: A gas sensing system measures a concentration of a gas sample having an absorption peak at a first wavelength. An emitter emits light having a spectrum that includes at least the first wavelength. A sensor detects at least some of the light emitted by the emitter. A porous scattering material is substantially transparent at the first wavelength and scatters at least some of the light. A surface of the porous scattering material opposing the emitter and the sensor has a depression. The emitter and the sensor are laterally and vertically separated by a separator filling the depression. The separator specularly or diffusively reflects the light emitted by the emitter.

Abstract: A gas sensing system measures a concentration of first and second gasses in a gas sample disposed in a cavity containing a porous scattering material. The first and second gas each have an absorption peak at a different wavelength. First and second emitters emit light having a spectrum that includes one of the different wavelengths. A single sensor, or multiple sensors, detect at least some of the light emitted by the first and second emitters. A processor determines concentration of the first and second gases from signals from the sensor that indicate intensities of the light from the first and second emitters. When a single sensor is used, the first and second emitters are driven, and the sensor signal detected, at different times. When multiple sensors are used, the sensors detect signals at one of the absorption peaks.

Abstract: Pixelated array light emitters are formed with closely-spaced pixels having ultra-smooth sidewalk. In methods for making such pixelated array light emitters, a converter layer of phosphor particles dispersed in a binder is disposed on a carrier, and then singulated by saw cuts or similar methods to form an array of phosphor pixels. The binder is fully cured prior to singulation of the converter layer. Further, the carrier is rigid rather than flexible. As a consequence of fully curing the binder and of using a rigid carrier to support the converter layer, singulation results in phosphor pixels having smooth side walls. The array of phosphor pixels is subsequently attached to a corresponding array of LEDs with an adhesive layer, separate from the binder used to form the converter layer. The pixel sidewalls may be formed with controlled morphology, for example at acute or obtuse angles with respect to the carrier.

Abstract: A device including a phosphor layer having a plurality of holes or pockets arranged within the phosphor layer to reduce lateral light transmission. The phosphor layer can be sized and positioned to extend over a plurality of LED emitter pixels.

Abstract: Systems for apparatuses formed of light emitting devices. Solutions for controlling the off-state appearance of lighting system designs is disclosed. Thermochromic materials are selected in accordance with a desired off-state of an LED device. The thermochromic materials are applied to a structure that is in a light path of light emitted by the LED device. In the off-state the LED device produces a desired off-state colored appearance. When the LED device is in the on-state, the thermochromic materials heat up and become more and more transparent. The light emitted from the device in its on-state does not suffer from color shifting due to the presence of the thermochromic materials. Furthermore, light emitted from the LED device in its on-state does not suffer from attenuation due to the presence of the thermochromic materials. Techniques to select and position thermochromic materials in or around LED apparatuses are presented.