摘要:
A lighting device for generating colored and white light. According to the invention the lighting device comprises at least one light source (1, 4) emitting blue or ultraviolet light and a color conversion unit (2, 5) for converting said blue or ultraviolet light into visible light comprising at least two sections (2a, 2b, 2c, 6a, 6b, 6c, 6d), at least one section (2c, 6d) of which being a transparent or translucent color converting section, said color conversion unit (2, 5) being arranged for alternately illuminating said at least two sections (2a, 2b, 2c, 6a, 6b, 6c, 6d) with said blue or ultraviolet light, said at least one color converting section containing luminescent material, wherein said luminescent material is a luminescent organic dye in a polymer matrix or a crystalline inorganic luminescent material.
摘要:
The invention relates to an electronic circuit and a method of supplying energy to a high-pressure gas-discharge lamp H, 65, 75. The electronic circuit comprises a line-supply input section 62, 72 to receive and convert an a.c. voltage from an a.c. line-supply system 61, 71, an energy storage means 63, 73 to store the energy put out by the line-supply input section 62, 72 and a lamp-current regulating unit 64, 74 that is supplied with an input voltage U1 by the line-supply input section 62, 72 via the energy storage means 63, 73 and that makes available a lamp current I2 for a high-pressure gas-discharge lamp II, 65, 75. To make it possible for the energy storage means 63, 73 to be particularly small, it is proposed that the lamp-current regulating unit 64, 74 have a power section L, D, C, S, A1, A2, K having a transconductive property. If there is a drop in the input voltage U1, this property then automatically produces a reduction in the lamp current I2 made available to a high-pressure gas-discharge lamp 65, 75, H. This ensures a particularly fast adjustment to voltage fluctuations. The invention also relates to a corresponding method.
摘要:
The invention relates to an image projector with a High-Intensity-Discharge HID lamp (112) and a method of operating it. Such lamps have the disadvantage that their voltaic arc jumps back and forth between different positions at unforeseeable times during operation. This so-called arc jumping has the effect of changing the brightness, i.e. the overall brightness and/or the brightness distribution of the light emitted by the HID lamp (112). For the viewer of an image projected with such a projector, this effect appears as a jolt of this projected image. To avoid such effects for the viewer, it is first proposed according to the invention that changes in the brightness of the light in the image projector's beam path are detected. As soon as a change in brightness caused by an arc jump has been detected, this brightness is reset to a brightness detected at a moment t-2 before the arc jump, in order subsequently to convert it during a predetermined time interval T to the brightness resulting from the arc jump. This resetting must occur so soon after the arc jump, and the conversion so slowly, that the changes in the brightness of the light incident on a picture screen device (118) resulting from the arc jump, the reset, and the conversion are not perceptible to the human eye.
摘要:
The invention relates to a method of determining a zero point (V0) of a current sensor in a circuit arrangement for operating a gas discharge lamp. The invention is characterized by the following process steps: the current (11) through the sensor is switched off for a short period during a first half wave (13) and a first test value (V6) is determined, then the current (11) through the sensor is switched off for a short period during a second half wave (14) having a different polarity and a second test value (−V7) is determined, whereupon an average value is formed of the two test values (V6, −V7), and the zero point (Vx, V0) is determined by means of said average value. It is prevented thereby that the zero point drifts during lamp operation, for example owing to heating, and that amplitudes of the positive and negative half waves (13, 14) of the lamp current (11) are formed differently. Impairment of lamp life and visible artefacts in a presented projection image are prevented.
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:
Current switching point determination devices use two comparators with fixed threshold values. A power inverter control device for switching point determination is provided which includes a filter circuit and a subsequent single comparator. By this arrangement, the time event is independent of the amplitude and for sufficiently small frequencies also of the frequency.
摘要:
A controller is described, which is particularly suited for a power supply with switching elements (S1, S2), such as a switching mode power supply. The controller comprises a logical unit (18) which calculates a binary state value Zk by a first logical operation from a binary input value I and a prior binary state value Zk−1. The logical unit further calculates a binary output value Y by a second logical operation from the binary input value I and the binary state value Zk. In this way, fast and efficient fully digital control may be realized especially for a switching mode power supply, where the binary input value I is a comparator value and the binary output value Y is used to drive the switch elements (S1, S2). An adaptation unit (20), which may be a signal processor, determines the logical operations and delivers them to the logical unit (18) during operation of the controller unit (16).
摘要:
The invention relates to a circuit arrangement for operating a gas discharge lamp with a current. According to the invention, the current comprises a high-frequency AC component and a low-frequency AC component.
摘要:
The invention relates to a circuit (1) and a method for operation of a gas discharge lamp (3) with a switching transformer (2), which switching transformer comprises a switch (22), a converter inductor (24) and a control means (27) in a control loop (33) for measuring a lamp voltage and setting a desired power. In accordance with the invention, the switching transformer (2) comprises a second control loop (80). By means of the second control loop the switching transformer is adjustable to individual lamp conditions.
摘要:
The invention relates to an electronic circuit and to a method of supplying a high-pressure discharge arc lamp (12). The circuit comprises a DC-AC converter, for which purpose two controllable switching elements T1, T2 are connected in the form of a half bridge to an operating potential U+ and a reference potential (10). The circuit further comprises a two-stage filter arrangement. The lamp is connected to a coil Lign of the second filter stage, and the same connection terminal of this coil Lign is connected to the reference potential (10) via a capacitor Cign. To make the circuit as small and as economical as possible, while high high-frequency interference peaks and strong currents in the circuit are avoided, it is proposed that a coil Trfilt of the first filter stage has at least three taps. The first, outer tap is connected to the output of the half bridge, the second, central tap to the second connection terminal of the coil Lign, and the third, outer tap to the reference potential (10) via a capacitor Cfilt.