OSRAM SYLVANIA INC.
|OSRAM SYLVANIA INC. Patent applications|
|Patent application number||Title||Published|
|20150257223||HYBRID DIMMING CONTROL TECHNIQUES FOR LIGHTING DRIVERS - Techniques are disclosed for independent control of individual LED strings driven from a single AC current source. A lighting driver circuit includes a DC-AC inverter with series resonance that provides a current that may be split into multiple currents for driving multiple LED assemblies. Current splitting transformers may be used to divide the current from the AC source, and the amplitude of the current from the AC source may be determined by a microcontroller. In some cases the current splitting transformers provide galvanic isolation to the LED assemblies. The multiple LED assemblies may be controlled by a number of switches that may independently activate the individual LED assemblies based on the duty cycle of multiple PWM signals provided to the switches by the microcontroller. When all of the PWM signals output from the microcontroller are on an off-cycle, the current source may be turned off.||09-10-2015|
|20150257222||HYBRID DIMMING CONTROL TECHNIQUES FOR LED DRIVERS - Techniques are disclosed for dimming LED strings using frequency modulation (FM) dimming and burst control dimming. At high brightness levels, FM dimming may be used to decrease the current through LED strings by increasing the switching frequency of pulses within a pulse train of an AC current source. At low brightness levels, or after the switching frequency has been increased to the resonant frequency of the current source, burst control dimming may decrease the current through LED strings by decreasing the duty cycle of the pulse train of the current source. At high brightness levels, FM dimming and burst control dimming may be combined by decreasing the duty cycle of the pulse train at each of a number of increasing switching frequency values. FM dimming may also be combined with frequency hopping in order to increase the number of available frequency steps.||09-10-2015|
|20150253489||Lightguide Design Techniques - Techniques are disclosed for obtaining a desired luminance and/or intensity distribution from any lighting fixture that is illuminated by a lightguide. The techniques can be used, for instance, to design a non-uniform surface texture (e.g., of light extraction features) for a lightguide, wherein the surface texture achieves a desired uniform or an intentionally non-uniform luminance distribution for a given lightguide shape/geometry, dimensions, and/or composition. In some embodiments, an iteration algorithm with illuminance distribution feedback is utilized to design a non-uniform surface texture (e.g., geometry, dimensions, quantity and/or spatial distribution of light extraction features) to achieve the target luminance distribution for a given lighting application.||09-10-2015|
|20150243840||Strain Relief Superlattices and Optoelectronic Devices Including the Same - Structures for transitioning between two layers of differing lattice parameters are disclosed. In some embodiments, the structures are in the form of a superlattice that serves as a strain relieving transition between two layers of differing lattice parameters. By controlling the properties of the superlattice, the superlattice can exhibit desirable properties such as transparency to light and lattice matching to one of the two layers of differing lattice parameters. Optoelectronic devices such as light emitting diodes including such superlattices are also disclosed.||08-27-2015|
Patent applications by OSRAM SYLVANIA INC.