摘要:
A projection system for image reproduction by means of at least one lamp (10) as well as a sensor (30) for generating a sensor signal for monitoring changes in the luminous flux generated by said at least one lamp (10) and for compensating these changes through a suitable control of the image reproduction is described. The projection system comprises a device (31; 32; 36, 37) for eliminating substantially periodic interference components from the sensor signal generated by the at least one sensor (30; 301, 302, 303). These interference components may be generated by an optical component such as in particular a color modulator (12) of the projection system. The invention thus renders possible an at least substantially interference-free compensation of fluctuations in the luminous flux generated by the lamp (10), for example owing to an unstable arc discharge, also in those color systems in which the positioning of the sensor (30) in the projection system is non-critical.
摘要:
In order to improve the efficiency of a driver circuit for controlling upper and lower switching means (T3, T4) for converting a direct voltage Ud into a clocked output voltage Ua for a resonant converter with a high-voltage section (HT) for controlling the upper switching means (T3) and a low-voltage section (NT) for controlling the lower switching means (T4), which switch the switching means (T3, T4) on alternately to one another, the switch-on phases of the switching means (T3, T4) being separated from one another by dead-time phases, there is provided a first circuit section which controls the duty cycle Δtein3 of the upper switching means (T3) as a function of the duty cycle Δtein4 of the lower switching means (T4), and receives control signals from the low-voltage section (NT) exclusively during the duty cycle Δtein4 of the lower switching means (T4).
摘要:
A device for profile extrusion, has at least three clamping arrangements disposed equidistantly around the perimeter of an extended profile, wherein a clamping element can be placed directly on the extended profile. The one clamping element can be mounted in each of the clamping arrangements and the clamping elements can be moved radially with respect to the extrusion axis by a drive mechanism, and each clamping arrangement is connected to the adjacent clamping arrangement by a coupling arrangement.
摘要:
The present invention relates to an LED lamp (1) adapted for operation with an alternating current. The LED retrofit lamp (1) comprises a LED unit (7, 7′, 7″, 7′″) and a compensation circuit with a controllable switching device (9, 9′), connected parallel to said LED unit (7, 7′, 7″, 7′″) to provide an alternate current path. A control unit (10, 10′, 10″) is adapted to control said switching device (9, 9′) in a compensation mode in which said switching device (9, 9′) is set to the conducting state for the duration of a shunt period in each half cycle of the alternating current to allow adapting the power/current of the inventive LED lamp (1), so that a versatile and optimized operation of the lamp (1) is possible.
摘要:
Driver circuits (1) for driving load circuits (2) comprising first and second light circuits (21-22, 71-72) are in first/second modes for input voltages having first/second voltage amplitudes, the second voltage amplitudes being larger than the first voltage amplitudes. The first light circuits (21, 71) are on in the first and second modes. The second light circuits (22, 72) are off in the first modes and are on in the second modes. A control circuit (21, 71) in dependence of the modes to extend control. These currents may get smaller current amplitudes in higher modes. Light outputs of the first light circuit (21, 71) may get smaller in higher modes. A total light output of all light circuits (21-22, 71-72) may remain substantially constant during all modes.
摘要:
Bleeder circuits (1) for combinations of phase cutting dimmers (2) and light emitting diode circuits (3) comprise active circuitry (4) to increase a number of options. The active circuitry (4) may comprise a current limiting circuit (5) for limiting a current flowing through the bleeder circuit (1). The active circuitry (4) may comprise a voltage detecting circuit (6) for activating or deactivating, in response to a detection result, the current limiting circuit (5) and may comprise control circuitry such as a micro processor circuit (7) for controlling the current limiting circuit (5) and may comprise a control circuit (9) for using information derived from a current flowing through the light emitting diode circuit (3) for controlling the current limiting circuit (5) and for controlling at least a part of the light emitting diode circuit (3) that comprises anti-parallel light emitting diodes (31-32) or serial and/or parallel light emitting diodes (33-36).
摘要:
A method for driving a high-pressure gas discharge lamp of a projector system, which is suitable to produce and to supply to a light valve device during a projection interval (4) a light beam of a basic color which is selected from several basic colors (G, R, B). The lamp is driven by a lamp current. During said projection interval light valves of the light valve device are controlled in a pulse width modulation manner to have each valve provide a respective wanted light integral over said projection interval. During at least one of a number of successive projection intervals associated with one basic color a magnitude of the lamp current is temporarily reduced for at least a time that all light valves can be controlled for said one basic color.
摘要:
Disclosed is a method for adjusting light output of a projector that includes compiling a switching sequence having long and short segments for the controllable elements of a display unit, a long segment being of a duration greater than or equal to a threshold and a short segment being of a duration less than the threshold; obtaining a light output adjustment measure by which the light output is to be adjusted; generating a light pulse sequence such that the duration of a light pulse corresponds to the light output adjustment measure; and arranging the light pulse relative to the switching sequence such that the activation of the light pulse does not occur during a short segment, wherein the predefined threshold is a time duration of the light pulse at a lowest dimming level such that the light pulse has settled by the time the long segment ends.
摘要:
In light emitting diode circuits (1) comprising serially coupled first and second circuits (11, 12) with first and second light emitting diodes, third circuits (13) are coupled in parallel with the second circuits (12) for controlling the first light emitting diodes in the first circuits (11) and/or third light emitting diodes in fourth circuits (14). This allows more options, more optimizations, more flexibility and/or more efficiency. The light emitting diode circuit (1) receives a supply voltage from a source (2, 3) for feeding the light emitting diode circuit (1). The third circuit (13) receives a feeding voltage from the second circuit (12) for feeding the third circuit (13). The feeding voltage may be a voltage present across the second circuit (12). The third circuit (13) may further control the second light emitting diodes in the second circuit (12). Said controlling may comprise controlling a current flowing through said light emitting diodes for the purpose of dimming, flicker suppression, color control and/or temperature protection.
摘要:
The invention describes a method of driving a discharge lamp (1), wherein a blackening value (N) is determined, which blackening value (N) represents a level of blackening of the interior of the lamp (1), and a recovery parameter (2, T) is calculate based on the blackening value (N). When the lamp power is increased above the saturation power level, the lamp (1) is driven according to the recovery parameter (2, T) for the duration of a specific recovery time. The invention further describes a driving arrangement (70, 70′), and a projector system (10) comprising a high-pressure discharge lamp (1) and such a driving arrangement (70, 70′).