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 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.
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:
A projection system for image display with at least one lamp (1), with at least one sensor (5) for detecting changes in the luminous flux delivered by said at least one lamp (1) and for compensating these changes through a suitable control of the image display and/or the lamp is described. The projection system is remarkable in that a light integrator (3) is provided, into which at least a portion of the light provided by the lamp (1) is coupled in, while the sensor (5) is optically coupled to the light integrator (3) such that it detects the luminous intensity present in the light integrator (3). Since this luminous intensity is very homogeneous because of the multiple reflections and is not influenced by brightness fluctuations caused by an optical component such as, for example, a color modulator (4), a very accurate compensation of changes in the luminous flux generated by the lamp (1) is made possible by the sensor signal.
摘要:
The invention relates to a method for enhancing brightness and contrast in images provided by a projection-based presenter utilising a display panel (5) illuminated by at least one scrolling band of light and a lamp (3) as a light source for said at least one scrolling band of light. In order to enable such an enhancement, it is proposed that the method comprises modulating the light output of the lamp (3) between different scrolling positions in a way that a higher light intensity is supplied by said lamp (3) when parts of the display panel (5) currently representing brighter parts of a respective image are illuminated by said at least one scrolling band of light than when parts of the display panel (5) currently representing less bright parts of said image are illuminated by said at least one scrolling band of light. The invention relates equally to a corresponding projector, and to an image processor and a regulation and controlling system for such a projector.
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 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:
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 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:
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.