摘要:
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. A lumped wavelength range of the set of LEDs is a range of said first and second wavelength sub-ranges, and the set of characteristics of the set of LEDs is a function of said first and second sets of characteristics. A method for controlling the sets of LEDs is also disclosed.
摘要:
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. A lumped wavelength range of the set of LEDs is a range of said first and second wavelength sub-ranges, and the set of characteristics of the set of LEDs is a function of said first and second sets of characteristics. A method for controlling the sets of LEDs is also disclosed.
摘要:
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. The control system in turn comprises means for providing feedback of the flux of at least one of the LED light sources, the feedback being based on input from an unfiltered sensor (22) responsive to the actual flux of the individual LED light source, for allowing control of the at least one LED light source in accordance with the feedback, and means for providing first control data based on input from a filtered sensor (36) responsive to the first wavelength flux, for allowing adjustment of at least one LED light source, to compensate for first wavelength leakage of the wavelength converted LED light source(s). The present invention also relates to a system and method for controlling a LED lighting unit.
摘要:
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.
摘要:
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.
摘要:
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).
摘要:
A method of controlling an electronic ballast for a lighting circuit, the ballast including a bleeder, for use with dimmer circuits, by, in response to a mains supply being connected to the lighting circuit, determining whether a dimmer circuit is present in the lighting circuit; and in response to determining a dimmer circuit is not present, disconnecting the bleeder from the lighting circuit at least until the mains supply is disconnected. The method may be used during, and the determination of whether a dimmer circuit is present is stored at least until the mains supply is disconnected. Determination of either a leading or trailing edge phase cut dimmer may be made by looking for deviation from the expected sine-wave voltage, either directly through temporal or voltage deviation, or indirectly by examining the second differential of the voltage with respect to time.
摘要:
A method is disclosed of controlling a LED, comprising driving the LED with a DC current for a first time, interrupting the DC current for a second time such that the first time and the second time sum to a period, determining at least one characteristic of the LED whilst the DC current is interrupted, and controlling the DC current during a subsequent period in dependence on the at least one characteristic. The invention thus benefits from the simplicity of DC operation. By operating at the LED in a DC mode, rather than say in a PWM mode, the requirement to be able to adjust the duty cycle is avoided. By including interruptions to the DC current, it is possible to utilise the LED itself to act as a sensor in order to determine a characteristic of the LED. The need for additional sensors is thereby avoided.
摘要:
The present invention relates to a method for determining drive values for driving a lighting device at a desired brightness and color. The method comprising the steps of determining a first luminous flux weight ratio based on the desired color and a first drive current for driving each of the differently colored LEDs, determining a first luminous flux for each of the differently colored LEDs based on the desired brightness and the first luminous flux weight ratio, comparing, for each of the differently colored LEDs, the first luminous flux with a nominal luminous flux for a plurality of different drive currents, selecting, for each of the differently colored LEDs, a preferred drive current that at least can produce the first luminous flux, determining a second luminous flux weight ratio based on the desired color and the selected drive currents for each of the differently colored LEDs, determining a second luminous flux for each of the differently colored LEDs based on the desired brightness and the second luminous flux weight ratio, and determining a duty cycle for each of the differently colored LEDs at the selected drive currents, wherein the selected currents at the determined duty cycles produces the second luminous flux for each of the differently colored LEDs. The present invention provides for the possibility to limit the number of necessary computational steps for determining preferred drive currents. Furthermore, an increase in number of current level and/or differently colored LEDs would only slightly increase the computational cost.
摘要:
A connector (100) for connecting a component (102) to a heat sink (104), wherein the connector (100) is formed as a female part of a bayonet coupling enclosing an opening (106) for receiving one of the component (102) and the heat sink (104). Further, the connector (100) in use is arranged to ensure direct thermal contact between the component (102) and the heat sink (104) in the opening (106).