Abstract:
The invention relates to phosphor-conversion (PC) sources of white light, which are composed of at least two groups of emitters, such as blue electroluminescent light-emitting diodes (LEDs) and wide-band (WB) or narrow-band (NB) phosphors that partially absorb and convert the flux generated by the LEDs to other wavelengths, and to improving the quality of the white light emitted by such light sources. In particular, embodiments of the present invention describe new 3-4 component combinations of peak wavelengths and bandwidths for white PC LEDs with partial conversion. These combinations are used to provide spectral power distributions that enable lighting with a considerable portion of a high number of spectrophotomethcally calibrated colors rendered almost indistinguishably from a blackbody radiator or daylight illuminant, and which differ from distributions optimized using standard color-rendering assessment procedures based on a small number of test samples.
Abstract:
A composite contact for a semiconductor device includes a DC conducting electrode that is attached to a semiconductor layer in the device, and a capacitive electrode that is partially over the DC conducting electrode and extends beyond the DC conducting electrode. A method of fabricating a semiconductor device with a composite contact includes forming the composite contact to a semiconductor layer in a semiconductor structure. The composite contact is formed by forming a DC conducting electrode attached to a semiconductor layer in a semiconductor structure and forming a capacitive electrode that is partially over the DC conducting electrode and extends beyond the DC conducting electrode. The composite contact provides a combined resistive-capacitive coupling to the semiconductor layer. As a result, a contact impedance is reduced when the corresponding semiconductor device is operated at high frequencies.
Abstract:
A two-stage amplifier is provided, which in the first stage, a first amplifier generates a non-linear square wave based on a harmonic input. The non-linear square wave has the same frequency as the harmonic input and is provided as an input to the second stage, in which a second amplifier generates an amplified harmonic output. The first amplifier and/or second amplifier can comprise a group-ll nitride-based Heterostructure Field Effect Transistor (HFET). Additionally, the first amplifier can comprise a multi-harmonic Class F amplifier and the second amplifier can comprise a Class E amplifier.
Abstract:
An approach for controlling ultraviolet intensity over a surface of a light sensitive object is described. Aspects involve using ultraviolet radiation with a wavelength range that includes ultraviolet-A and ultraviolet-B radiation to irradiate the surface. Light sensors measure light intensity at the surface, wherein each sensor measures light intensity in a wavelength range that corresponds to a wavelength range emitted from at least one of the sources. A controller controls the light intensity over the surface by adjusting the power of the sources as a function of the light intensity measurements. The controller uses the light intensity measurements to determine whether each source is illuminating the surface with an intensity that is within an acceptable variation with a predetermined intensity value targeted for the surface. The controller adjusts the power of the sources as a function of the variation to ensure an optimal distribution of light intensity over the surface.
Abstract:
An approach for controlling light exposure of a light sensitive object is described. Aspects of this approach involve using a first set of radiation sources to irradiate the object with visible radiation and infrared radiation. A second set of radiation sources spot irradiate the object in a set of locations with a target ultraviolet radiation having a range of wavelengths. Radiation sensors detect radiation reflected from the object and environment condition sensors detect conditions of the environment in which the object is located during irradiation. A controller controls irradiation of the light sensitive object by the first and second set of radiation sources according to predetermined optimal irradiation settings specified for various environmental conditions. In addition, the controller adjusts irradiation settings of the first and second set of radiation sources as a function of measurements obtained by the various sensors.
Abstract:
A solution for controlling mildew in a cultivated area is described. The solution can include a set of ultraviolet sources that are configured to emit ultraviolet radiation in an ultraviolet range of approximately 260 nanometers to approximately 310 nanometers to harm mildew present on a plant or ground surface. A set of sensors can be utilized to acquire plant data for at least one plant surface of a plant, which can be processed to determine a presence of mildew on the at least one plant surface. Additional features can be included to further affect the growth environment for the plant. A feedback process can be implemented to improve one or more aspects of the growth environment.
Abstract:
A diffusive ultraviolet illuminator is provided. The illuminator can include a reflective mirror and a set of ultraviolet radiation sources located within a proximity of the focus point of the reflective mirror. The ultraviolet radiation from the set of ultraviolet radiation sources is directed towards a reflective surface located adjacent to the illuminator. The reflective surface can diffusively reflect at least 30% the ultraviolet radiation and the diffusive ultraviolet radiation can be within at least 40% of Lambertian distribution. A set of optical elements can be located between the illuminator and the reflective surface in order to direct the ultraviolet radiation towards at least 50% of the reflective surface.
Abstract:
An adjustable multi-wavelength lamp is described. The lamp can include a plurality of emitters. The emitters can include at least one ultraviolet emitter, at least one visible light emitter, and at least one infrared emitter. The lamp can include a control system for controlling operation of the plurality of emitters. The control system can be configured to selectively deliver power to any combination of one or more of the plurality of emitters to generate light approximating a target spectral distribution of intensity.
Abstract:
A fluid treatment system and method of treating fluid is described. The fluid treatment system can include a fluid transparency meter, which acquires data corresponding to an ultraviolet transparency of the fluid and a disinfection chamber within which a set of ultraviolet sources emit ultraviolet light onto the fluid located therein. The treatment system can include various features for mixing the fluid and/or recirculating the fluid for multiple ultraviolet light doses. A control system can manage a flow of the fluid through the fluid treatment system based on a disinfection dose delivered to the fluid.
Abstract:
A solution for fabricating a device is described. The solution can include fabricating a heterostructure for the device, which includes at least one stress controlling layer. The stress controlling layer can include one or more attributes varies as a function of a lateral position based on a target variation of stresses in a semiconductor layer located directly under the stress controlling layer. Embodiments are further directed to a heterostructure including at least one stress controlling layer and a device including the heterostructure.