Abstract: In the case of an apparatus for providing a sinusoidally amplitude-modulated operating voltage, two switches are arranged in the form of a half bridge, and an LC element is arranged downstream of the half bridge. The first switch is driven by a first square-wave signal in a clocking with the amplitude modulation frequency per clock cycle, and the second switch (QLOW) is driven by a second square-wave signal, which is shorter than the first signal, with a temporal offset with respect to the first signal in each clock cycle. The LC element (LMOD, CMOD) acts as a filter for the signal resulting from the driving of the switches at a connection point (K) between the switches and allows a DC voltage component and a sinusoidal component of the signal with the fundamental frequency of the clocking to pass through, but substantially filters out harmonics.

Abstract: The invention relates to a low-pressure discharge lamp comprising a glass discharge vessel (1) which is substantially tubular in form and which is closed in a gas-tight manner on the ends thereof, a filling consisting of an inert gas mixture and quicksilver, in addition to an optional luminous coating on the inner wall of the discharge vessel (1). Two current supply inlets are respectively melted into the two ends of the discharge vessel (1), with a helical electrode secured thereto (5). The invention is characterized in that in order to increase the switching resistance of the lamp in a cold start operation, at least one other electrode (7,8) made of a conductive material is arranged in the region between the helical electrode (5) and the connecting end of the discharge vessel (1) and one end of said other electrode (7, 8) is electrically connected to one of the two current supply inlets (3,4).

Abstract: The operating method is based on the simultaneous application of FM and AM. In this process, the fundamental frequency of the AM is derived from at least one, preferably the second, longitudinal mode. In continuous operation of the lamp, the color temperature is set for a prescribed power by setting the AM degree controllably.

Abstract: An inventive method for determining the bulb temperature (T) of high pressure discharge lamps is disclosed that comprises the following steps: ascertaining a first spectral radiant power (MP) at a first wavelength (?P); ascertaining a second spectral radiant power (MC) at a second wavelength (?C) different from the first; determining the quotient (?) from the first and second radiant power; and determining the temperature (T) of the bulb on the basis of this quotient. It likewise discloses an apparatus for carrying out the inventive method.

Abstract: The bulb of the lamp is closed at opposite ends by sealing parts (6), with in each case one cap (8) being fitted at one end, the cap having an electrical contact element (13) which is connected in an electrically conductive manner to a supply conductor (15) leading to a luminous means, the contact element being accommodated in a tubular extension (11) of the sealing part. The cap part (8) has an adjustment part (14; 24), which is directed inward with respect to the interior of the lamp and is in contact with the sleeve (11) via a bracket.

Abstract: Circuit arrangement having a converter without a transformer but with an inductor for the pulsed operation of dielectric barrier discharge lamps The circuit arrangement according to the invention comprises an inductor-type converter for the pulsed operation of dielectric barrier discharge lamps (EL). The invention proposes both a half bridge variant and a full bridge variant. By selecting the inductance value of the inductor (L), it is possible to influence the edge steepness of the pulses, in the case of more than one inductor even independently for the rising and falling edges.

Abstract: The invention relates to a novel ballast for a discharge lamp, in which a continuous-operation control circuit is brought out of operation when a physical operation, which defines a preheating time, of a preheating timer has as yet not been sufficiently returned if the lamp is intended to be restarted.

Abstract: The invention relates to a circuit arrangement for detecting a crest factor of a lamp current or a lamp operating voltage of an electric lamp (2), the circuit arrangement having a first subcircuit (15), which is designed to determine an averaged value from an input signal applied to the circuit arrangement, having a second subcircuit (16), which is designed to determine a maximum permissible value from the input signal applied to the circuit arrangement and having a comparator circuit (17), which is designed to produce a comparison signal from the output signal of the first subcircuit (15) characterizing the averaged value and from an output signal of the second subcircuit (16) characterizing the maximum permissible crest factor. The invention also relates to a method for detecting such a crest factor. One further aspect of the invention relates to an electronic ballast (1) which has a circuit arrangement (14a, 14b) according to the invention.

Abstract: The invention relates to a method for designing a discharge lamp for use with a light-gathering system, in particular of a projector for data or video projection. Also disclosed are a lamp designed using such a method and a reflector provided therefore.

Abstract: A coated luminescent material having a luminescent material powder formed by grains, the luminescent grains being coated, and the coating being at most 5 nm, preferably at most 2 nm.

Abstract: An electric lamp having a base at one end, a lamp bulb sealed in a vacuum-tight manner, the lamp bulb being surrounded by an envelope part, a base having electrical connections bearing on one side the outer bulb and on the other side the envelope part, having the following features: a) the base has a base insulator which has a central opening in which the outer bulb is accommodated without cement; b) the base insulator has a circular, radially projecting segment having an upper and lower plateau which is associated with the base; c) on the base side the envelope part has a circular opening having a radially projecting edge which has a lower and an upper contact surface in relation to the base, the lower contact surface matching the upper plateau; and d) the envelope part is fixed to the base via a cement-free, mechanical retaining mechanism.

Abstract: An adapter for providing a recessed lamp in a screw-type lampholder. This adapter has an electrical contact-making device, via which an electrical connection is produced between a screw base, which can be introduced into the screw-type lampholder, of the adapter and the recessed lamp once the recessed lamp has been introduced into the adapter. Furthermore, the adapter has a switchable electrical connecting device, via which, in the state in which there is no mechanical connection between an enveloping bulb for the recessed lamp and the adapter, an electrical connection is not produced between the screw base and the recessed lamp, and via which, in the state in which the recessed lamp is surrounded, at least in sections, by the enveloping bulb, an electrical connection is produced between the screw base and the recessed lamp. As a result, the recessed lamp in the adapter can only be operated with the enveloping bulb placed thereon.

Abstract: An illumination device, comprising a light emitting diode (11) fixed on a circuit board (12). The illumination device furthermore has an optical element (10) disposed downstream of the light emitting diode (11) in a main emission direction (15), the optical element (10) being configured for directing a first portion (6a) of the electromagnetic radiation (9) emitted by the light emitting diode (11) during operation through the circuit board (12) in a direction away from the circuit board (12).

Abstract: A ballast having a dimming device for a low-pressure discharge lamp. It has two technically different possibilities for controlling the lamp brightness. The first possibility for controlling the lamp brightness is by means of adjusting the amplitude of the lamp current. The second possibility for brightness control is based on the fact that the low-pressure discharge lamp can be operated with a pulsed lamp current. In particular, both operating modes are used in combination in specific brightness ranges.

Abstract: A ballast having a dimming device for a low-pressure discharge lamp. For brightness control, the DC component of the periodically modulated envelope of the lamp current is varied. In this case, the current does not fall below predetermined minimum values for the lamp current. Phases with a high lamp current are characterized by a steep rising edge, compared with a flatter falling edge.

Abstract: The metal halide lamp has a ceramic discharge vessel and contains two groups of metal halides: a first group made up of the emitters and a second group made up of the wetters. The second group comprises at least one of the metal halides of Mg or Yb.

Abstract: In the metal halide high-pressure discharge lamp for stage, film and television lighting systems and for projection technology and effect lighting, the discharge vessel contains dysprosium and cesium as fill metals for the metal halides. Optimum results for dimmability, arc instability and color rendering are achieved if the fill additionally includes 0.12 to 3.8 ?mol of vanadium and if appropriate 0.05 to 1.0 ?mol of zirconium per ml of vessel volume. These metals achieve improved color rendering, in particular red rendering, with an Ra of from 70 to 95 and an R9 of from 45 to 90.

Abstract: The invention relates to a phosphor composition for lamps with a lattice of monoclinic crystal structure (monazite) of type (1?g)[((1?c?a)*Ln, c*Ce, a*A)PO4]×g*GeO2, in which Ln is at least one element selected from the group consisting of lanthanum La, gadolinium Gd and/or Yttrium Y and A is at least one activator selected from the group consisting of terbium Tb, praseodymium Pr and/or europium Eu, and 0?a?1.0; 0?c?1.0, and 0<g?0.2.

Abstract: The present invention relates to an electronic ballast for discharge lamps, for example low-pressure discharge lamps, having a converter having a switching element and a two-part lamp inductor which is connected upstream and downstream of the discharge lamp. An electronic ballast according to the invention has a smoothing circuit which reduces voltage jumps caused by switching operations in the converter at the lamp terminals.

Abstract: A voltage converter, whose topology can be switched over between a boost converter and a SEPIC. The boost converter has ripple current compensation. As a result, the inductors used can be utilized in optimum fashion. A thyristor which is protected against breakdown triggering by a negative gate voltage is used as the changeover switch.