Abstract: An x-ray tube disclosed here in includes an emitter arranged to emit electrons on to a focal spot on a rotatable anode. The x-ray tube also includes a hollow tube arranged to receive electromagnetic radiation from the focal spot at one end of the hollow tube and transmit it to another end. The x-ray tube also includes two or more sensors arranged to detect the electromagnetic radiation through the hollow tube.

Abstract: The invention relates to an illumination device (1) with a number of light emitters, for example LEDs (L1, L2, L3, L4) of individual emission spectra. Sensor units (D1, D2, D3, D4) can produce a vector of measurement signals (S1, S2, S3, S4) that represent the light output of a single active light emitter. Based on a linear relation obtained during a calibration procedure, a characteristic value of the light output of that light emitter (L1, L2, L3, L4) is then calculated from the measurement vector, wherein said characteristic value is based on the coefficients of a decomposition of the individual emission spectrum into basis functions.

Abstract: According to an exemplary embodiment of the present invention, a lighting system for communication with a remote control device is provided, which comprises a light emitting element adapted for emitting modulated light to the remote control and for detecting control signals from the remote control. This may provide for a communication between the remote control and the lighting system without the need of an extra sensor or an extra transmitter.

Abstract: Adjusting a driving signal for a lighting device by obtaining a temperature of the lighting device, and adjusting at least one parameter of a conversion procedure depending on the obtained temperature. Further a set-point of a desired colour and/or brightness is converted into a set-point of colour sensor coordinates with the conversion procedure. The actual colour values of the lighting device are obtained, and the driving signal is adjusted based on a difference between the colour sensor coordinates set-point and the obtained colour values.

Abstract: In a method and a driver circuit for operating one or more light emitting diodes, LEDs, an alternating supply current is generated and transformed to an alternating secondary winding voltage. Using rectifier means, such as diodes or synchronous switches, the alternating secondary winding voltage is converted to a substantially constant load current by using a buffer element, such as an output choke, i.e. a suitable inductor. The power transferred from the power source to the LEDs may be controlled by frequency control of the alternating supply current.

Abstract: Operating a lighting device by acquiring a target brightness level of at least one solid-state lighting unit, and determining a reference driving current amplitude for obtaining the target brightness level. If the reference driving current amplitude is below an optimum driving current amplitude, the solid-state lighting unit is operated at the optimum driving current amplitude, which is pulse-width modulated to obtain the target brightness level.

Abstract: A lighting device, and a lighting system including such a lighting device and an adjustable power source, includes at least one LED, a control device employing a device for measuring a quantity that is indicative of an electrical resistance of the LED at a predetermined current or voltage, a power supply control device for controlling an adjustable electrical power supply for driving the LED. The electrical resistance of a LED is functionally dependent of the LED's junction temperature, which in turn determines its optical output characteristics. Thus, by measuring the junction temperature indirectly, through measuring of electrical LED characteristics, and mapping them to a temperature, LED output control is possible.

Abstract: The present invention relates to a method for controlling an illumination device (100), the illumination device (100) comprising a flux sensing unit (101) and at least two differently colored light sources (102, 103, 104), the method comprising the steps of switching on and off each of the light sources according to a predefined pattern, acquiring measurement values by means of the flux sensing unit at predetermined intervals in accordance with the predefined pattern, calculating a color point for each of the light sources based on the measurement values, calculating a difference between the color points and corresponding reference color points, and adjusting an analog current drive level of the light sources, wherein the difference is minimized such that a desired color is obtained. The present invention provides for the possibilities to in a more accurate way correct for the color changes due to change in drive current, temperature, and aging effects.

Abstract: An electroluminescent device (7) comprising at least one electroluminescent light source (2) and at least one electronic component (3) for driving the electroluminescent light source (2), which electronic component (3) is arranged in such a way as to be separated in space from the electroluminescent light source (2), the electrical connection between the electroluminescent light source (2) and the electronic component (3) being made by a flexible film (8) having electrically conductive regions (82) and at least one electrically insulating surface (81).

Abstract: The present invention relates to a lighting device, as well as to a lighting system comprising such a lighting device and an adjustable power source, and also relates to a method of driving such a lighting system. The lighting device comprises at least one LED (1a, 1b), a control device that comprises a measuring means (7, 9) to measure a quantity that is indicative of an electrical resistance of said LED at a predetermined current or voltage, a power supply control means (11) connected to said measuring means (7, 9) and constructed to control an adjustable electrical power supply (3a, 3b) for driving the LED (1a, 1b), said signal being based on said value of said quantity. The electrical resistance of a LED is functionally dependent of the LED's junction temperature, which in turn determines its optical output characteristics. Thus, by measuring the junction temperature indirectly, through measuring of electrical LED characteristics, and mapping them to a temperature, LED output control is possible.