Abstract: A switched mode power converter is disclosed, together with a method for operating the same. The power converter is adapted to be operable in the boundary conduction mode, and operation is interruptible in the absence of any load requirement.

Abstract: A driver for driving an LED uses PWM in a sequence of the periods. The driver has a modulo counter, that is reset after each period. The driver has a first adder for combining the count value with a quantity indicative of a shift of the LED's control pulse relative to the start of the period; a second adder for combining the count value with a width quantity indicative of a width of the control pulse; and a logic gate receiving the MSBs at the outputs of the adders and supplying the control pulse.

Abstract: Controlling an arrangement of semiconductors of which different semiconductors emit light of different distinct colors is disclosed, whereby a feed forward control part, which is dependent on a junction temperature of semiconductors for each color, is operated with first intervals and is adjusted dependent on measure light output for each color with much longer second intervals.

Abstract: The present invention relates to a light emitting diode (LED) luminary system (10) comprising a plurality of LED light sources (14) of multiple colors for producing a mixed color light, and means (28) for controlling the LED light sources in accordance with differences between set point values representing a mixed color light having a desired color and first control data representing the color of the mixed color light produced by the LED light sources, the first control data being provided by at least one color sensor (22). The system is characterized by means (30, 32) for deriving the temperature of each LED light source, and means (26) for compensating the set point values in accordance with second control data including the LED light source temperatures. This offers increased color stability for the system. The invention also relates to a method and system for controlling a LED luminary.

Abstract: The present invention relates to a control system (12) for controlling the light output of a light emitting unit (10), which light emitting unit comprises at least one light emitting diode (LED) (14) and is adapted to emit light of at least one color, the control system comprising: a sensor unit (18) adapted to detect the light output of the light emitting unit and provide a corresponding feedback signal; and a control unit (22) adapted to control the light output of the light emitting unit based on a comparison between the feedback signal and a corresponding reference signal representing a desired light output, in order to provide an improved light output, wherein the control unit is further adapted to: determine a random switching period; determine on-time(s) for the LED(s) within the random switching period for providing the improved light output; and control energizing of the LED(s) according to the determined period and on-time(s).

Abstract: The present invention relates to a method of controlling the output of a luminaire comprising an array of LEDs emitting light of at least one color. The array has single color LED groups, wherein each group consists of at least one LED. The method comprises the following steps for each LED group:spectrally filtering the light emitted by the LED group by means of a first filter as well as by means of a second filter; detecting the spectrally filtered light from said first and said second filter and generating respective first and second response signals, wherein the levels of said first and second response signals are related to the respective amounts of detected spectrally filtered light; and controlling the light output of said LED group on the basis of said first and second response signals, wherein the filter characteristics of said first and said second filter are at least partly non-overlapping. The invention also relates to a corresponding control system for performing the method.

Abstract: The present invention relates to a lighting device (10) comprising a tiled light guide (16) comprising a central tile (12b) and at least one end tile (12a, 12c), the end tile(s) (12a, 12c) being arranged at an edge (24, 26) of the light guide (16); at least one solid state light source (18) arranged for coupling light into the light guide (16) in a general direction towards or away from the end tile(s) (12a, 12c); and a plurality of out-coupling structures (20) arranged for coupling light out of the light guide (16); wherein the end tile(s) (12a, 12c) has inherent in-coupling and/or inherent out-coupling of light different from the central tile (12b).

Abstract: A luminaire arrangement for providing a luminous flux in a target direction (z) comprising a light guide (101), multiple light sources (103) arranged at said light guide for emitting light into said light guide, out coupling means (106) arranged at said light guide and adapted to direct light out from said light guide; and a cover layer (102) arranged in front of said light guide at the side where light it to be directed out, said cover layer being provided with at least one optically transparent area (104) such that light directed out from said light guide is allowed to pass said cover layer. The cover layer allows for use of the same or similar light guide, light sources and out coupling means in a number of different luminaire applications, where each application may have different requirements on e.g. appearance, and/or collimation and/or directivity of the luminous flux.

Abstract: The present invention relates to a method for determining drive values for driving a lighting device at a desired brightness and color.

Abstract: The present invention relates to a system (100) for controlling light output of a lighting system. The system (100) comprises a light mixing circuit (116) comprising a plurality of light sources configured to provide a mixed light output (102) and mounted on a heat-sink (202) together with a temperature sensing means and a controller (108) receiving a set-point (110) from a calibration matrix (104) and generating a driving signal (120, 122) for the light mixing circuit (116). The controller (108) comprises a rescale unit (118) configured to measure power of the driving signal (120, 122) and to rescale the driving signal (120, 122) when the power exceeds a predetermined power threshold, and the controller is configured to receive the heat-sink temperature signal (206) and to calculate a junction temperature from the heat-sink temperature signal, and the controller (108) generates the driving signal (120, 122) as a function of the junction temperature.

Abstract: A lighting arrangement provides light of a desired color. The arrangement includes light sources that each emit light of a respective color that, when mixed, is perceivable as the desired color. A light detector is configured to receive light reflected by a color reference surface having a specific reference color. A controller is configured to analyzes a signal from the light detector and recognizes the color of the received light as the color of the reference surface. The controller controls the light sources such that the desired color corresponds to the color of the color reference surface.

Abstract: It is presented a method for controlling a light level of light emitting diodes, LEDs, comprised in a light sensor segment comprising a light sensor and a plurality of LEDs, the method comprising the steps of: turning on all LEDs in an LED segment, comprising at least one of the plurality of LEDs, detecting a light level associated with the LED segment, by detecting a light level using the light sensor, repeating the steps of turning on all LEDs in an LED segment and detecting a light level, until all of the plurality of LEDs are turned on, and for each LED of the plurality of LEDs, controlling a light intensity of the each LED of the plurality of LEDs, the intensity control depending on the detected light level associated with an LED segment containing the each LED of the plurality of LEDs. A corresponding light sensor array, backlight for a display system and liquid crystal display are also presented.

Abstract: The present invention relates to a control system (10; 30; 50) for a LED luminary (12) including a plurality of LED light sources of multiple colors for producing a mixed color light. The control system comprises means (22) for controlling the LED light sources in accordance with a difference between set point values representing a desired light output and first control data provided by at least one optical sensor (14; 32) responsive to a property of the light produced by the LED light sources. The control system is characterized by means (26; 38) for compensating said set point values in accordance with second control data provided by a temperature sensor (24) responsive to the temperature of the optical sensor(s) (14; 32). The additional temperature sensor makes it possible to compensate for changes in the spectral sensitivity of the optical sensor(s), whereby the color stability of the LED luminary with integrated optical sensors can be increased.

Abstract: An illumination system (1) comprises a plurality of light sources (11, 12, 13), each provided with a driver (21, 22, 23); a controller (30) for generating control signals (Sc1, Sc2>Sc3) for controlling the respective drivers; temperature feed forward means (60, 61, 62, 63, 81) for establishing a temperature feed forward (TFF) correction mechanism; flux feedback means (71, 82, 83, 84) for establishing a flux feedback (FFB) correction mechanism. The controller is capable of operating in a first mode of operation wherein both the temperature feed forward correction mechanism and the flux feedback correction mechanism are active, and is capable of operating in a second mode of operation wherein the temperature feed forward correction mechanism is active and the flux feedback correction mechanism is inactive. The controller is designed to monitor the duty cycles of the control signals and to select its mode of operation based on said duty cycles.

Abstract: The present inventions relates to a method for adjusting the light setting for a multi-color light source, which method comprises receiving input from a user related to at least one of white color, hue, and chroma, and adjusting white color, hue, and chroma of the light source in accordance with the user input. The method is characterized in the step of automatically changing a current hue and chroma level when the user input is received. This automatic change makes possible to render the subsequent adjustment in setting perceivable for the user, which facilitates the adjustment of the light source. The present invention also relates to a corresponding system and computer program product.

Abstract: The present invention relates to a light emitting diode (LED) module (10) comprising a substrate (12) having plural indents (14) and flattish portions (20) in between the indents, and LEDs (16) mounted in the indents. The LED module is characterized by at least one of sensors (22) and additional LEDs (32) provided at the flattish portions. This allows increased sensor detection accuracy and/or color compensation. The present invention also relates to a method for the manufacturing of such an LED module.

Abstract: The present invention relates to a light emitting diode (LED) lighting system (10) comprising a plurality of LED light sources for generating a mixed color light, the plurality of LED light sources including at least one LED light source comprising at least one LED adapted to emit light of a first wavelength and a wavelength converter for converting at least a portion of the light emitted from the LED(s) to light of another wavelength, and a control system (33) for individually controlling the flux output of the LED light sources.

Abstract: The present invention relates to a light emitting diode (LED) luminary system (10) comprising a plurality of LED light sources (14) of multiple colors for producing a mixed color light, and means (28) for controlling the LED light sources in accordance with differences between set point values representing a mixed color light having a desired color and first control data representing the color of the mixed color light produced by the LED light sources, the first control data being provided by at least one color sensor (22). The system is characterized by means (30, 32) for deriving the temperature of each LED light source, and means (26) for compensating the set point values in accordance with second control data including the LED light source temperatures. This offers increased color stability for the system. The invention also relates to a method and system for controlling a LED luminary.

Abstract: A method, for controlling color output of a variable color lighting system (1) capable of emitting light within a color gamut, comprising the steps of receiving (10) a request for a target color (T), converting the target color (T) to a set of lighting system control parameters, and applying (15) the set of lighting system control parameters, thereby controlling the color output of the lighting system (1).

Abstract: A light emitting diode (LED) lighting system for producing white light is disclosed. The system comprises sets of LEDs arranged to emit light with different wavelength ranges and associated with different sets of characteristics, and a driving circuit arranged to drive the LEDs. The driving circuit comprises an input for desired light intensity, color rendering index, and color temperature, an input for signals for LED temperature, a model for determining driving currents for said sets of LEDs from said parameters, signals, and characteristics for each of said sets of LEDs; and a current driver for the LEDs. At least one of the sets of LEDs comprises a first subset of LEDs with a first wavelength sub-range and a first set of characteristics, and a second subset of LEDs with a second wavelength sub-range and a second set of characteristics.