Abstract: The present invention relates to a method of operating a projection system comprising several solid state light sources (2, 3, 4) of different colour 13, 14, 15) and at least one spatial light modulator (1) having an array of switchable elements. Said array is illuminated by at least one of said light sources (2, 3, 4) for several illumination periods and is addressed such that the light is timely and spatially modulated to project images onto a screen. In the present method said light sources (2, 3, 4) are controlled to emit light modulated in amplitude (15) and/or time (18) during said illumination periods of said array. With the present method an increased greyscale resolution of the projection system can be achieved.

Abstract: A security system is described, comprising a sensor module (15) which accommodates a laser sensor (10) working with self-mixing interference. The laser sensor (10) generates measurement data which are related to the velocity of an object such as the body of a human being and, optionally, the distance between the laser sensor (10) and the object. Dependent on the measurement data assembled by the laser sensor (10) and supplied to a control circuit (30) such as an airbag computer, the airbag computer activate security means such as an airbag (35)in order to prevent injuries of the human body. Furthermore, a method of driving such a security system is described.

Abstract: A description is given of a method and a circuit arrangement for operating a high-pressure gas discharge lamp with a lamp current superposed with first current pulses, in particular in a system for the time-sequential production of (primary) colors and possibly white segments, from which an image to be displayed is synthesized, in which, in order to change or correct color and/or brightness properties of the image, the first current pulses are adjusted with regard to their amplitude and/or temporal length and/or temporal position relative to the production of the colors and/or white segments. A description is also given of a projection system comprising such a circuit arrangement.

Abstract: A lighting unit is described which has a discharge lamp (1), in particular a high pressure or high intensity discharge (HID) lamp or an ultra high performance (UHP) lamp, a lamp driver (2) and a cooling device (3). To reduce mechanical stresses caused by temperature variations in the lamp (1), one or more operating parameters of the lamp (1) are detected. In addition, a control unit is provided for controlling the lamp driver (2) and/or the cooling device (3) at least during switching on and/or off of the lighting unit in such a way that there is no excursion from a predetermined range of the at least one operating parameter. By selecting the parameter range suitably, the service life of the lamp may be extended considerably or the power of the lamp may be increased while the service life remains the same.

Abstract: The invention relates to a high-pressure discharge lamp which comprises at least a burner (2) having a symmetrical discharge chamber (21), where at least the outer contour of the burner (2) has an elliptical shape in the region of the discharge chamber (21), two electrodes (41, 42) extending into the discharge chamber (21) and arranged in mutual opposition on the major axis of symmetry of the discharge chamber (21), and a multilayer interference filter (3) arranged on the outer contour of the burner (2) in the region of the discharge chamber (21), wherein the interference filter (3) mainly reflects light from at least one wavelength range of the UV light into the space between the two electrodes (41, 42).

Abstract: The present invention is directed to a wavelength conversion layer (1) with a matrix layer (2) comprising embedded rare-earth-ion-doped micro-crystallites (3) and/or rare-earth-ion-doped amorphous particles, wherein said rare-earth-ion-doped micro crystallites and/or rare-earth-ion-doped amorphous particles are doped with at least one of the lanthanides, and wherein said rare-earth-ion-doped micro-crystallites and/or said doped amorphous particles have a mean diameter d50 of 10 nm to 500 müm, and wherein the matrix layer, is transparent, whereby the refractive indices of said rare-earth-ion-doped micro-crystallites and/or said rare-earth-ion-doped amorphous particles match the refractive indices of the matrix layer with an index fifference delta n such as: 0<_delta n<_0.1, for at least one wavelength in the range of 400 nm to 1200 nm.

Abstract: The present invention relates to an upconversion laser system comprising at least a semiconductor laser having a gain structure (4) arranged between a first mirror (5) and a second mirror (6), said first (5) and said second mirror (6) forming a laser cavity (7) of the semiconductor laser, and an upconversion laser for upconverting a fundamental radiation of said semiconductor laser. The upconversion laser system of the present invention is characterized in that the upconversion laser is arranged in the laser cavity (7) of the semiconductor laser. The proposed upconversion laser system has a compact design.

Abstract: A description is given of a high-pressure gas discharge lamp (HID lamp) which comprises an at least essentially mercury-free discharge gas and is suitable and/or intended for use in projection displays, in particular in the form of a short-arc lamp. A lamp voltage and efficiency which are comparable to mercury lamps are essentially achieved in that the discharge gas comprises a noble gas and also zinc as a voltage gradient former and light generator, wherein the pressure of the zinc in the gas phase is preferably approximately 30 bar in the operating state of the lamp. An evaporation which is necessary to achieve this pressure is made possible by increasing in particular the lowest temperatures in the discharge vessel. Various measures are proposed for increasing the temperature.

Abstract: A projection system includes an image projection apparatus window and a transparent holographic screen deflecting light from the image projection apparatus into discrete, mutually spaced directions so that an area which is free from images is formed between identical images. Projected, mutually spaced holographic frames of the image is visualized by the holographic screen that includes a film layer which is partially illuminated multiple times at different pick-up angles to the same object of an image, so that the film layer has hologram images of the same object at mutually different pick-up angles. The transparent screen may include many holographic film layers, in which each film layer is illuminated once at different pick-up angles to the same object, so that each film layer has one hologram image of the object at a different pick-up angle.

Abstract: The present invention relates to a method of operating a projection system comprising several solid state light sources (2, 3, 4) of different colour 13, 14, 15) and at least one spatial light modulator (1) having an array of switchable elements. Said array is illuminated by at least one of said light sources (2, 3, 4) for several illumination periods and is addressed such that the light is timely and spatially modulated to project images onto a screen. In the present method said light sources (2, 3, 4) are controlled to emit light modulated in amplitude (15) and/or time (18) during said illumination periods of said array. With the present method an increased greyscale resolution of the projection system can be achieved.

Abstract: A description is given of a method and a circuit arrangement for operating a high-pressure gas discharge lamp with a lamp current superposed with first current pulses, in particular in a system for the time-sequential production of (primary) colors and possibly white segments, from which an image to be displayed is synthesized, in which, in order to change or correct color and/or brightness properties of the image, the first current pulses are adjusted with regard to their amplitude and/or temporal length and/or temporal position relative to the production of the colors and/or white segments. A description is also given of a projection system comprising such a circuit arrangement.

Abstract: The invention relates to an illumination unit that comprises at least a reflector (3) and a UHP lamp (2), which UHP lamp has at least one burner (20) having a discharge chamber (21), wherein, when the lamp is operating, at least part of the IR light emitted from the burner material of the UHP lamp (2) makes its way back to at least a part of the burner (20) by reflection from the reflector (3) and/or from another component of the illumination unit (1).

Abstract: A projection system having a projection display (20), at least one light source (10), and a sensor means for sensing and compensating for changes in the luminous flux emitted by the at least one light source (10) is described. The sensor means comprises in this case at least one sensor arrangement (30; 31, 32; 33, 34) for sensing components (M) of the light from the light source (10) that are directed into a region surrounding an entering face of an optical component (11) of the projection system. It has been found that there is a very good correlation between these components (M) of the light from the light source (10) and those other components (I) of the light that actually reach the projection display (20), which means that by controlling a power supply unit (10c) for the light source (10) and/or a driver unit (20a) driving the projection display (20) in a suitable manner it is possible very effectively to suppress fluctuations in brightness that occur as a result of, for example, unstable arc discharges.

Abstract: The invention relates to a cooled high-pressure gas-discharge lamp, at least comprising a cooled envelope (43) that seals off hermetically a discharge chamber (431) filled with a gas, there being, at least in the discharge chamber (431), a non-uniform temperature distribution at the time of the gas discharge, and comprising a cooling means (7) having a coolant, which cooling means (7) produces a directed flow (9) of coolant, there being a liquid coolant acting on the envelope (43) of the lamp, it being possible for the lamp to be operated at a higher power, and the flow (9) of coolant being such that, when the power consumption of the lamp is increased, any devitrification of the envelope (43) of the lamp and any condensation of the gas is substantially prevented.

Abstract: The present invention is directed to a wavelength conversion layer (1) with a matrix layer (2) comprising embedded rare-earth-ion-doped micro-crystallites (3) and/or rare-earth-ion-doped amorphous particles, wherein said rare-earth-ion-doped micro crystallites and/or rare-earth-ion-doped amorphous particles are doped with at least one of the lanthanides, and wherein said rare-earth-ion-doped micro-crystallites and/or said doped amorphous particles have a mean diameter d50 of 10 nm to 500 müm, and wherein the matrix layer, is transparent, whereby the refractive indices of said rare-earth-ion-doped micro-crystallites and/or said rare-earth-ion-doped amorphous particles match the refractive indices of the matrix layer with an index fifference delta n such as: 0?delta n?0.1, for at least one wavelength in the range of 400 nm to 1200 nm.

Abstract: The invention relates to a high-pressure discharge lamp which comprises at least a burner (2) having a symmetrical discharge chamber (21), where at least the outer contour of the burner (2) has an elliptical shape in the region of the discharge chamber (21), two electrodes (41, 42) extending into the discharge chamber (21) and arranged in mutual opposition on the major axis of symmetry of the discharge chamber (21), and a multilayer interference filter (3) arranged on the outer contour of the burner (2) in the region of the discharge chamber (21), wherein the interference filter (3) mainly reflects light from at least one wavelength range of the UV light into the space between the two electrodes (41, 42).

Abstract: A projection system for image reproduction includes at least one lamp and sensor for generating a sensor signal for monitoring changes in the luminous flux generated by the lamp and for compensating these changes through a suitable control of the image reproduction. The projection system further includes a device for eliminating substantially periodic interference components from the sensor signal generated by the sensor. These interference components may be generated by an optical component such as a color modulator of the projection system. The projection system provides substantially interference-free compensation of fluctuations in the luminous flux generated by the lamp, for example, owing to an unstable arc discharge. Further, the positioning of the sensor in the projection system may not be critical.

Abstract: The invention relates to a method for operating a discharge lamp 11 including two electrodes 12,13. The method comprises applying to the electrodes an alternating current ILamp. In order to improve the performance of the lamp and to increase the life time of the lamp, it is proposed that the alternating current has a direct current component DC for compensating a temperature difference between the two electrodes. The direct current component is selected more specifically such that a first electrode, which is expected to have a lower temperature than the second electrode, functions as anode for the direct current component, while the second electrode functions as cathode for the direct current component. The invention relates equally to an electronic circuit and to a software program for operating a discharge lamp correspondingly, as well as to a lighting system comprising a discharge lamp and means for operating this discharge lamp correspondingly.

Abstract: The present invention relates to the use of photonic band gap materials with phosphors incorporated. Photonic band gap materials play an important role for LEDs as light sources in applications where either a high radiance is desirable or LEDs are used in optical systems. The optical properties of current LEDs are such that the radiance is rather low and cannot be increased by standard means. It is an object of the invention to improve the radiance of light emitting devices by making use of photonic band gap materials with phosphors incorporated.

Abstract: A method and a circuit arrangement for the operation of a high-pressure gas discharge lamp (HID [high intensity discharge] lamp or UHP [ultra high performance] lamp) is described, which lamp is particularly suitable for illuminating projection displays with sequential color rendering (for example LCOS or SCR-DMD systems) with a pulsatory lamp current. Artefacts in the color rendering are avoided through the generation of at least one compensation pulse of a given amplitude and a given timing and through superimposition thereof on the lamp current.