EP2382846A2 - Procédé et appareil électronique pour faire fonctionner une lampe à décharge, et projecteur - Google Patents

Procédé et appareil électronique pour faire fonctionner une lampe à décharge, et projecteur

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Publication number
EP2382846A2
EP2382846A2 EP10700722A EP10700722A EP2382846A2 EP 2382846 A2 EP2382846 A2 EP 2382846A2 EP 10700722 A EP10700722 A EP 10700722A EP 10700722 A EP10700722 A EP 10700722A EP 2382846 A2 EP2382846 A2 EP 2382846A2
Authority
EP
European Patent Office
Prior art keywords
lamp
voltage
commutation
gas discharge
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP10700722A
Other languages
German (de)
English (en)
Inventor
Martin BRÜCKEL
Bärbel Dierks
Peter Flesch
Josef KRÖLL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Original Assignee
Osram GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osram GmbH filed Critical Osram GmbH
Publication of EP2382846A2 publication Critical patent/EP2382846A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
    • H05B41/292—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2928—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the lamp against abnormal operating conditions

Definitions

  • the invention relates to a method and an electronic operating device for operating a gas discharge lamp, wherein the gas discharge lamp is operated with a rectangular lamp current.
  • the invention also relates to a projector having such a control gear.
  • gas discharge lamps have increasingly been used instead of incandescent lamps because of their high efficiency.
  • high-pressure discharge lamps are more difficult to handle with respect to their operation than low-pressure discharge lamps, and the electronic control gear for these lamps are therefore more expensive.
  • Display systems such as DLP projectors (short for "digital light processing projector"), include a lighting device with a light source whose light is directed to a DMD chip (short for "digital mirror device chip”).
  • the DMD chip comprises microscopically small pivoting mirrors which either direct the light onto the projection surface if the associated pixel is to be switched on or direct the light away from the projection surface, for example onto an absorber if the associated pixel is to be switched off.
  • Each mirror thus acts as a light valve that controls the light flux of a pixel.
  • These light valves are called DMD light valves in the present case.
  • DMD light valves for color generation comprises a DLP Proj ector in the case of a lighting device that emits white light, such as a filter wheel, which is arranged between lighting device and DMD chip and filters of different colors, such as red, green and blue contains. With the aid of the filter wheel, light of the respectively desired color is let through sequentially from the white light of the illumination device.
  • the color temperature of such display systems is generally related to the color location of the light of the illumination device. This usually changes with the operating parameters of the light sources of the lighting device, such as voltage, current and temperature. Furthermore, depending on the light source used, the ratio between current intensity and luminous flux is not necessarily linear. This leads to a change in the current also to a change in the color location of the light of the light source and thus to a change in the color temperature of the display system.
  • the color depth of the display system is limited by the minimum duty cycle of a pixel.
  • dithering in which individual pixels are switched at a frequency lower than the regular frequency of 1/60 Hz.
  • this usually leads to a visible to the human observer noise.
  • the contrast ratio of the display system is defined by the ratio of maximum light flux with fully opened light valves to minimal light flux with fully closed light valves.
  • the minimum light flux can be further reduced with completely closed light valves by means of a mechanical diaphragm.
  • a mechanical shutter takes up space in the lighting device or display system, increases the weight of the lighting device or the display system, and also provides an additional potential source of noise.
  • High intensity discharge lamps as used in such display systems can also be dimmed but thrown the dimmed operation has problems with the electrode temperature and the arc approach of the high pressure discharge lamp. The bow approach is fundamentally problematic when operating a gas discharge lamp with alternating current.
  • commutation is considered to be the process in which the polarity of the voltage of the gas discharge lamp changes, and therefore, a large current or voltage change occurs.
  • the voltage or current zero crossing is detected. It should be noted that the voltage commutation usually always runs faster than the current commutation.
  • the inner end of the lamp electrode which is in the discharge space of the gas-discharge lamp burner, is referred to as the electrode end.
  • the electrode tip is a needle-shaped or hump-shaped elevation on the end of the electrode, the end of which serves as a starting point for the arc.
  • a major problem of high-pressure discharge lamps is the change or deformation of the electrodes over the entire service life.
  • the shape of the electrode changes away from the ideal shape towards a more and more fissured surface, especially at the inner end of the electrode.
  • the discharge arc always forms from electrode tip to electrode tip. If there are several electrode tips of equal size on an electrode, it can lead to a bow jump and thus to a flickering of the lamp.
  • Electrode tips which have not grown up in the center worsen the optical imaging since the optics of a projector or of a luminaire in which such a gas discharge lamp is used are designed for a specific position of the discharge arc and, in particular, adjusted to the initial state of the electrodes and of the discharge arc.
  • uneven growth of the electrode tips may occur so that the arc is no longer centered, but axial displaced in the burner vessel is arranged. This deteriorates the optical image of the entire system as well.
  • the fracture leads to an increase in the original electrode spacing and thus also influences the lamp voltage. Since this increases in proportion to the distance, a premature life shutdown can occur, as it usually responds when the lamp voltage exceeds a predetermined threshold. In summary, there is a reduction in the lamp life and the quality of the light emitted by the lamp.
  • the cited document proposes applying a current pulse to the electrodes in such a way that the grown-up electrode tips are thereby melted back. Thereby the distance between the electrodes can be increased again, the lamp voltage can be increased, and thus the required current can be lowered.
  • the present invention relates to the problem of providing a method in which the electrodes are kept as possible over the entire life of the gas discharge lamp in an optimal state in which the electrodes are at a distance from each other, as far as possible the original distance at a corresponds to new lamp, as well as to keep the surface of the electrode ends smooth with centrally grown tips, which form a defined starting point for the arc.
  • the method should also have the ability to be able to meet external constraints when synchronizing the commutation.
  • the teaching of WO 2007/045599 A1 therefore does not solve the abovementioned problem.
  • the solution of the object with respect to the method is carried out according to the invention with a method for operating a gas discharge lamp (LP), the gas discharge lamp (LP) is operated with a rectangular lamp current, and the lamp current over time has predetermined commutation, and on These commutation can be commutated to generate a Kommut réellesmusters.
  • LP gas discharge lamp
  • this commutation pattern is preferably so pronounced that the temporal mean value of the commutation pattern preferably corresponds to a predetermined frequency.
  • the gas discharge lamp can be operated at the optimum frequency for it.
  • the commutation pattern is generated by omitting the commutation points at which no commutation is to take place. This represents the simplest embodiment, which also offers a good operational safety, since only the commutations are carried out, which are absolutely necessary.
  • the commutation pattern is generated by the fact that at the commutation, where no commutation is to take place, yet a commutation ststtfindet, but this is reversed by an immediately following further commutation.
  • This procedure is also called double commutation.
  • the rectangular lamp current can be exactly synchronized with respect to a higher-level control, although a frequency which is optimal for the gas discharge lamp can be adjusted over the time average of the lamp current. It is thus possible to control the square-wave lamp current in its fundamental frequency and in its phase position with respect to a higher-level control, e.g. the video electronics of a projector to synchronize, and still produce any frequency necessary for the optimized operation of the gas discharge lamp.
  • 1 is a graph showing the relationship between the duration of a voltage applied to the gas discharge lamp DC voltage phase and the lamp voltage for a first embodiment of the operating method.
  • FIG. 2 is a graph illustrating a second embodiment of the method of operation
  • FIG. 3 is an illustration of a pair of electrodes before and after optimization by the method in the second embodiment
  • 5 shows the course of the lamp current in a mode of operation with maintenance pulses
  • 6a is a graph showing the relationship between the lamp voltage and the commutation frequency in a first embodiment of the third embodiment of the method of operation
  • Fig. 6b is a graph showing the relationship between the lamp voltage and the commutation frequency in a second embodiment of the third embodiment of the method of operation;
  • Fig. 6c is a waveform of the lamp current for the second embodiment of the third embodiment of the method of operation
  • FIG. 7 shows a signal flow graph for schematically illustrating a fourth embodiment of an operating method
  • FIG. 10 shows the state of the front part of the electrodes in the initial state (FIG. A)), after the overmelting (FIG. B)), and the growth of the electrode tips in the initial phase (FIG. C)) and in the state of completed regeneration (Fig. D));
  • Fig. 11 shows the time course of the lamp current and the lamp voltage when driven with asymmetric current duty cycle during the overmolding phase.
  • 12 is a schematic representation of an embodiment of a lighting device for carrying out the method
  • FIG. 13 is a schematic sectional view of a first embodiment of a display system
  • FIG. 14 is a schematic diagram of a light curve used in the first embodiment of the display system.
  • 15A-C are schematic diagrams of three exemplary light curves for operating a lighting device according to the operating method of the fifth embodiment
  • FIG. 16 shows a schematic diagram of an exemplary current intensity illuminance characteristic of a light source for operating a lighting device according to the invention.
  • FIG. 17 shows a schematic circuit diagram of an exemplary circuit arrangement for carrying out the method according to the invention.
  • Fig. 1 is a graph showing the relationship between the duration of a voltage applied to the gas discharge lamp DC voltage (curve VT), a distance between two DC voltage phases (curve OT), a voltage change in the DC voltage phase (curve VP) and the lamp voltage for a first embodiment of the operating method according to the invention.
  • the curve VT thus represents the length of the DC voltage phase as a function of the lamp voltage.
  • the curve OT represents the distance, also referred to below as the blocking time, between two DC voltage phases, ie the time until a DC voltage phase is again applied to the gas discharge lamp. Since, upon application of a DC voltage phase, the electrode melts more or less and the electrode spacing and thus also the lamp voltage increases, this is greater after the DC voltage phase than before the DC voltage phases.
  • the curve VT now shows the change in the lamp voltage during the DC voltage phase as a function of the lamp voltage.
  • the change may be quite large, in the present case up to 5V, since an increase in the electrode spacing is strongly desired.
  • the maximum change in lamp voltage should only be IV.
  • the inventive method ensures a defined distance of the electrode tips and a smooth as possible, little rugged form of the electrode ends over the entire life of the gas discharge lamp. This is achieved by DC clamping achieved on demand, which melt over the electrode ends as required and also promote electrode growth.
  • DC voltage phases consist of the omission of a few commutations. These omissions are placed so that the electrodes are always only mutually charged, that is, once the one electrode acts as an anode during a DC voltage phase, then acts after a break with normal lamp operation, the other electrode during a DC voltage phase as an anode. The frequency itself is not changed. In a positive DC voltage phase always only a first electrode of the gas discharge lamp is heated, in a negative DC voltage phase, only a second electrode of the gas discharge lamp is always heated.
  • the DC voltage phases are thus generated by the omission of commutations or by insertion of pseudo commutations. In the second variant, they are thus no DC voltage phases in the narrower sense, since in between the voltage and thus the current direction per pseudo-commutation is reversed twice, and quite a few pseudo-commutations per 'DC voltage phase' can occur.
  • a so-called maintenance pulse can accelerate the peak growth of the electrode tip, and preferably after a long DC phase applied to grow again on the oval or round electrode end an electrode tip, which produces a good arc starting point.
  • a maintenance pulse is a short current pulse which is applied to the gas discharge lamp shortly before or shortly after the commutation in order to heat the electrode.
  • the length of the maintenance pulse is between 50 ⁇ s and 1500 ⁇ s long, whereby the current level of the maintenance pulse is greater than in steady state operation. This achieves an overmelting of the outer end of the electrode tip whose thermal inertia has a time constant of approximately 100 ⁇ s.
  • the lamp is always applied at regular intervals with a DC voltage phase whose length depends on the lamp voltage.
  • the distances between two DC voltage phases are dependent on the lamp voltage.
  • the method now uses the characteristic curve VT according to FIG. 1 for the calculation of the length of the DC voltage phases which are applied to the gas discharge lamp.
  • the length of the DC voltage phases is in the preferred embodiment at 65V 40ms, the DC voltage phases become longer with decreasing voltage, and then reach a length of 200 ms at 60V.
  • the length of the DC voltage phases can vary between 5 ms and 500 ms depending on the lamp type.
  • the DC voltage phases are applied to the gas discharge lamp at regular intervals. The distances depend on the lamp voltage, but not shorter than 180s.
  • the duration between two DC voltage phases (OT blocking time) as shown in FIG. 1 (curve OT) is 200s at 60V lamp voltage, rising to 600s at 65V lamp voltage, then dropping back to 300s at HOV lamp voltage.
  • the duration between two DC voltage phases increases from 180s at 60V to 300s at 65V, then drops again to 180s at HOV lamp voltage.
  • the time span between two DC voltage phases can vary between 180s and 900s, depending on the lamp type. In summary, it can thus be said that at lower voltage, the DC voltage phases are more often applied to the gas discharge lamp and are also longer and thus more energy-rich.
  • the frequency of the DC voltage phases also increases again to reach 200ms again at HOV. Between the DC voltage phases is in the normal - I i
  • the frequency of the DC voltage phases is minimal in this area.
  • the length of the DC voltage phases is about 40 ms in the preferred embodiment.
  • the length of the DC voltage phases can be between 0 ms and 200 ms depending on the lamp type. For some lamp types, the DC voltage phases in this area can be completely dispensed with.
  • the duration of the DC voltage phases in the preferred embodiment varies from 40ms at 75V to 200ms at HOV lamp voltage of the gas discharge lamp burner. Depending on the lamp type, the duration of the DC voltage phases can vary from 2 ms to 500 ms.
  • the time span between two DC voltage phases in the present embodiment is 180 s at 60 V lamp voltage, then rises to 600 s at 65 V lamp voltage, and drops to 300 s at HOV lamp voltage.
  • the time span between two DC voltage phases can vary between 180s and 900s, depending on the lamp type. In summary, it can be said that the duration of the DC voltage phases increases with increasing lamp voltage, the DC voltage phases being applied more frequently to the gas discharge lamp with increasing lamp voltage and with very low lamp voltage.
  • the length of the DC voltage phases is not controlled by a characteristic, but the length of the DC voltage phases is controlled by the lamp voltage in the DC voltage phase itself.
  • the curve VP already described above describes the maximum voltage change of the lamp voltage in the DC voltage phase as a function of the lamp voltage. The voltage change is measured during the DC voltage phase.
  • the circuit implementing the method has a measuring device which can measure the lamp voltage before the DC voltage phase and above all the change of the lamp voltage during a DC voltage phase. The change in the lamp voltage during the DC voltage phase is evaluated in response to a termination criterion, and the DC voltage phase when the voltage is reached Abort criterion finished.
  • Fig. 2 is a graph illustrating the method of the second embodiment.
  • the gas discharge lamp is operated in normal operation without application of DC voltage phases. But leaves the lamp this voltage range, DC voltage phases are applied to the lamp.
  • the length of the DC voltage phases depends on the lamp voltage and above all on the change in the lamp voltage which is applied during the DC voltage phases.
  • the DC voltage phases are maintained until the lamp voltage has risen by a previously calculated or a predetermined value ⁇ Ui, ⁇ U2.
  • the voltage increase of the lamp voltage in the DC voltage phase is between 0.5V and 8V depending on the gas discharge lamp. In a preferred embodiment, the desired voltage rise is between 5V at 60V and IV at 65V.
  • the DC voltage phase is terminated so as not to damage the electrodes.
  • the process is carried out anew, that is, the lamp voltage is measured and another DC phase applied when the lamp voltage is outside the optimum range of 65- 75V. These steps are repeated periodically until the lamp voltage is again in the optimum range.
  • a DC phase which has always been a positive phase for the first electrode and a negative phase for the second electrode, has been divided into these two phases to treat different states of the two lamp electrodes.
  • the length of the DC phase is determined for the previously calculated voltage rise for the first electrode and applied to the second electrode in a subsequent inverse DC phase.
  • the length of the DC voltage phases for each electrode is calculated from the voltage increase during the DC voltage phases.
  • the magnitude of the voltage increase is the same for both DC voltage phases.
  • an individual electrode forming takes place for centering the arc in the burner axis.
  • the following method steps are carried out:
  • the duration or voltage increase of the DC phase for the desired displacement of the electrode center of gravity is calculated proportional to the individual length of the electrode tip: [40] For an asymmetric electrode geometry after the
  • T T DC phase first electrode + T DC phase second electrode '
  • the optical system can optimize and thus maximize its overall efficiency through a control loop that includes the electrode forming mechanisms.
  • a method is also conceivable that the first embodiment and the second embodiment use mixed to obtain the electrodes and the electrode tips in an optimum state.
  • An advantageous mixture could include that at lamp voltages below the lower lamp threshold, a method of the second embodiment is used wherein the length of the DC phase is determined by the lamp voltage change during this DC phase and at lamp voltages above the upper lamp threshold a method the first embodiment is used, in which the length of the DC phase is calculated or given by a characteristic.
  • FIG. 3 shows an illustration of a pair of electrodes before and after optimization of the method in the second embodiment.
  • FIG. 3a shows a pair of electrodes 52, 54 with the electrode ends 521, 541 and the electrode tips 523, 543 prior to the application of the method in the second embodiment.
  • the center 57 of the electrodes is not at the optimum center 58 of the torch vessel because the electrode tip 543 has grown much further than the electrode tip 523. Therefore, the method in its second embodiment is used to compensate for asymmetric electrode geometry.
  • the electrodes 52, 54 look as shown in FIG. 3b: both electrode tips 523, 543 are again of equal length, the center 57 between the electrode tips again lies in the burner center 58.
  • the discharge arc burns optimally again in the center of the burner vessel, and the optical efficiency of the overall system is maximized.
  • FIG. 4 shows the profile of the lamp voltage U D c and of the lamp current I D c during a DC voltage phase with different temporal resolution.
  • the two curves are shown in a low temporal resolution of 4ms / DIV. It is especially good to see on the stream that the positive as well as the negative DC phase is composed of 3 normal half-waves. This can be seen well on the 2 needle-shaped current pulses 61, 62, which divides the DC voltage phase into 3 areas. The pulses can also be seen in the lamp voltage.
  • the lower graph shows one of these pulses in a larger temporal resolution of 8 ⁇ s.
  • the double commutation is best seen, especially at the lamp voltage U DC , the voltage U DC jumps with a positive edge to its upper value and about 2 ⁇ s later with a negative edge to its lower value, where it remains until the next commutation .
  • the lamp current I DC wants to swing after the first commutation, but is too slow, so that only a small current collapse is recorded during the 2us. This is because the current commutation, as already mentioned, proceeds more slowly than the voltage commutation.
  • FIG. 5 shows a profile of the lamp current in which the gas discharge lamp is operated with the above-mentioned maintance pulses MP. It can also be seen clearly here that the DC voltage phase DCP is composed of two half-waves HW, since two maintenance pulses MP occur in the DC voltage phase. [47] Thus, the DC voltage phases are composed of half-waves of the normal operating frequency, so that the highest operating frequency is always an integer or fractionally rational multiple of the frequency of the DC voltage phases.
  • a continuous adjustment of the operating frequency takes place as a function of the lamp voltage.
  • the method can be operated in various forms.
  • the operating frequency is changed in discrete steps, depending on the lamp voltage. The higher the lamp voltage, the higher the frequency becomes. Since commutation can take place only at certain times due to various boundary conditions in the overall system, the operating frequency can only assume a limited number of frequency values. If the gas discharge lamp is e.g. operated in a video projector with a color wheel, the operating frequency of the gas discharge lamp can only be commutated when the color wheel is in a position in which is currently changing from one color segment to the next. Due to the uniform number of revolutions of the color wheel, which in turn depends on the frame rate of the video image, in principle, the frequency of commutation over a revolution of the color wheel is fixed.
  • Operating frequency to be driven In order to operate the gas discharge lamp optimally, but should always be a fixed at a certain lamp voltage Operating frequency to be driven.
  • a lamp current with an operating frequency of 100 Hz is applied to the gas discharge lamp. Since the operating frequency can only assume a few discrete frequency values due to the above boundary conditions, the adaptation of the operating frequency to the lamp voltage is quite rough.
  • the highest operating frequency is the frequency at which commutation is also performed at all possible commutation times. This frequency is the highest frequency that can be represented in the system.
  • the possible commutation times which are predetermined by the abovementioned boundary conditions, for example of a color wheel, are, as already mentioned above, also referred to as commutation points.
  • the operating frequency of the gas discharge lamp is adjusted continuously on the basis of a characteristic curve.
  • the characteristic curve of a preferred embodiment is shown in FIG. 6b. Up to a certain lamp voltage of here 50V, the operating frequency always remains equal to about 100Hz. From a lamp voltage above 50V, the operating frequency increases continuously up to a lamp voltage of 150V. Due to the above embodiments, not every operating frequency can be approached directly. Therefore, a method is used in which the inverter operates the gas discharge lamp at a series of discrete frequencies, all of which represent an integer or fractionally rational fraction of the highest operating frequency.
  • 6c shows an exemplary waveform with commutation points 31, 32, 33, 34, 35, in which, if necessary, a commutation can take place. If a commutation occurs at each of these points, the highest operating frequency is generated, and one half-wave is exactly one half-wave in each case. Also in this embodiment, there are again the possibilities to omit commutations really, or instead omit the commutation to execute two fast commutations in a row.
  • the method is also suitable if the possible commutation points per se are not always equally spaced.
  • the different color sectors of the color wheel are also different in width, so that the time intervals of the possible commutation sites are different. This is not a problem in the present method, since the higher-level control unit can take this into account and from the multiplicity of frequencies exhibiting the different shafts through the above-mentioned temporal frequency distribution the time average of the resulting frequency exactly to the predetermined operating frequency of the gas discharge lamp can adapt.
  • FIG. 7 shows a signal flow graph for a schematic representation of a fourth embodiment of the method. This begins in step 100 with the start, ie ignition of the lamp. Subsequently, it is checked in step 120 whether at least one parameter lies in a range of values that is correlated with the fact that the first and / or the second electrode is rugged. As this Parameter is preferably the lamp voltage or the operating time since the first commissioning or since the last time the process or the distance of the electrodes into consideration. If the question is answered in the negative, the gas discharge lamp is operated in step 150 in normal lamp operation. If the question is answered yes, the lamp is initially also operated in step 125 in normal lamp operation.
  • a start criterion for overmelting is fulfilled.
  • the starting criterion can be, for example, the achievement of a specific lamp voltage U B ss o ii.
  • no overmelting step is performed during normal lamp operation.
  • the overmelting of the electrodes is initiated in step 135.
  • Fig. 8 shows a schematic representation of the time course of the lamp voltage U B of a discharge lamp after its switching. As can be seen, the lamp is operated within the first 45 seconds with a power P less than the nominal power P nom .
  • This phase is referred to as start-up phase, while the current supplied to the lamp is limited in order not to overload the gas discharge lamp or the electronic control gear.
  • the lamp voltage U B has not risen to its continuous operating value in the region after 45 s, the lamp is already operated there at the nominal power P nom , ie there is no current limitation active there.
  • This phase is referred to as a power control phase, during which the lamp is operated at substantially its nominal power.
  • the normal lamp operation is thus composed of a start-up phase, which starts with the start of the lamp, and a power control phase, which adjoins the start-up phase and after a certain time in the stationary state, while the gas discharge lamp substantially with their nominal parameters is operated.
  • the startup phase after switching on until 45 s is particularly suitable for carrying out the method since the burner temperature there is still low and the user is not yet operating the lamp for the intended purpose.
  • FIG. 9 shows a schematic representation of the time curve of the ratio of the power P to the nominal power P nO m in percent and of the lamp voltage U B during the performance of a preferred exemplary embodiment of the method.
  • the discharge lamp is operated with the nominal power P nO m.
  • the power P is lowered to 30% of the nominal power. This leads to cooling of the discharge lamp, from which the advantages already mentioned in connection with FIG. 2 result.
  • the discharge lamp is operated with a lamp current I which amounts to between 150 and 200% of the nominal lamp current I no m for overmolding of the electrodes.
  • the lamp is operated at a power which is approximately 75% of the nominal power Pn o m. Thereafter, ie, from time t 4 , the power is increased in 5% increments, each lasting about 20 minutes, until the nominal power reaches P nom or even beyond, resulting in the growth of new electrode tips. As can be seen from the course of the lamp voltage U B , this decreases from a constant value, which has been set during operation of the discharge lamp with the power Pn o m, during operation at a lower power and then gradually increases again.
  • FIG. 10a) to d) show the state of the front parts of the electrodes at different stages of performing the method.
  • Fig. 4a) shows the state before carrying out the method.
  • the front parts of the electrodes are clearly fissured, the electrode tips are arranged off-center, the distance between the electrodes is d a .
  • the state shortly after the overmolding of the front parts of the electrodes is shown in Fig. 10b).
  • Clearly visible is the hemispherical shape of the front parts of the electrodes, which are in the Melting due to the surface tension results. Instead of the fractures now shows a smooth electrode surface. The distance has grown to d b .
  • Fig. 11 shows the time profile of the lamp current, above, and the lamp voltage U B , below, when driven with asymmetric current Dutycyle during the overmelt phase. It is easy to see that individual commutations are executed twice in succession.
  • the fifth embodiment relates to an operation method that can be carried out by an operating device to improve image quality in an illumination device besides electrode forming.
  • the illumination device 10 comprises a light source 1, in the present case a gas discharge lamp, which emits light with a color location in the white region of the CIE standard color plate.
  • a gas discharge lamp In the gas discharge lamp 1 is a point light source with a very small arc distance, which has a high energy density of 100 W / mm 3 to 500 W / mm ⁇ .
  • the illumination device 10 according to FIG. 12 comprises an operating device 2, such as a function generator, which can provide electrical signals with a power of 100 W to 500 W and carries out the method according to the invention.
  • the operating device 2 controls the light source 1 according to the invention. method according to the invention with an electric current signal, which follows a light curve 3. Light curves 3 will be explained later in connection with FIGS. 13 and 15A to 15C.
  • the light curve 3 in the embodiment according to FIG. 15A comprises a periodic sequence of three segments S R , S G , S B.
  • the first segment S B is associated with the color blue, the second segment S R with the color red and the third segment S G with the color green.
  • This light curve 3 can be stored, for example, as an alternative to the light curve 3 according to FIG. 14 in the operating device 2 of the lighting devices 10, 11 used in the display systems according to FIG.
  • the different segments of the light curve are assigned to different partial half-waves, from which there is the alternating current to be applied to the gas discharge lamp, so that the lamp current follows the stored light curve. Since the light output of the gas discharge lamp correlates with the lamp current, the light output of the gas discharge lamp follows the stored light curve.
  • the first segment S B of the light curve of FIG. 15A is assigned the color blue and has a duration t B of approximately 1300 ⁇ s. During this time interval t B , the luminous flux of the illumination device 10, 11 is approximately 108%.
  • the first segment S B is followed by a second segment S R , which is associated with the color red and has a duration of t R.
  • a first time interval t R i of the time interval t R the luminous flux of the illumination device 10, 11 is about 150% in the short term, while the light flux in a second time interval t R 2, which adjoins the first time interval t R i directly and forms with this the time interval t R , is about 105%.
  • the time interval t R i is significantly shorter than the time interval t R 2.
  • the time interval t R i in the present case is approximately 100 ⁇ s, while the time interval t R 2 in the present case amounts to approximately 1200 ⁇ s.
  • the second segment S R is followed by a third segment S G , which is associated with the color green and has a duration t G of likewise approximately 1300 ⁇ s.
  • the time interval t G is divided as the time interval t R in two time intervals t G i and t G 2, wherein the first time interval t G i is significantly longer than the second time interval t G 2.
  • the first time interval t G i is present about 1200 ⁇ s, while the second time interval t G 2 of the green segment has a duration of about 100 microseconds.
  • the light curve 3 has a constant value of approximately 85%, which is temporarily lowered for the time interval t G 2 to a value of approximately 45%.
  • Figure 15B shows two light curves 3.
  • the diagrams represent the illuminance and the color as a function of time. They each contain a full period of the light curve shape, as a rule between 16 and 20 ms.
  • Segments S ⁇ , S G , S M , S R , S 0 , S B together, which are assigned to the respective color.
  • the individual segments S ⁇ , S G , S M , S R , S 0 , S B are again assigned time intervals t ⁇ , t G , t M , t R , t c , t B , which can be divided into two or more three time intervals t Y i, t Y 2 t, G i, t G 2, TMI tM2 / TM3 / t R i, t R 2 t c i, t C2, t C 3, t B i, t B 2 split, each one of the time intervals is significantly longer than the others.
  • the values of the light flux in the long time intervals of the individual segments can be taken from the table in FIG. 15D in the "segment light level" row.
  • the yellow and the green segment S ⁇ , S G have a constant light flux of 80% during the long time interval.
  • the magenta and red segments S M , S R have a luminous flux of 120% during the long time interval, while the cyan segment S 0 has a luminous flux of 80% during the long time interval and the blue segment S B has a luminous flux of 120%. during the long time interval.
  • At the end of each segment is a short period of time during which the light level is lowered more than the long time interval.
  • the luminous flux is at 40%, at the magenta and at the red segment S M , S R to a value of 60%, lowered to a value of 40% in the case of cyan segment S c and to a value of 60% in the case of blue segment S B. Furthermore, at the end of magenta segment S M and at the end of the cyan segment S 0 a communication instead, which is symbolized by arrows and is each associated with a relative to the long time interval raised light flux.
  • segment sizes of the different colors are not identical, as can be seen in the table in FIG. 15D in the row "segment size", but amount to 60 ° at the yellow and the green segment S ⁇ , S G the magenta segment S M has a value of 40 °, the value of the red segment S R is 70 °, the cyan segment S c has a value of 62 °, and the blue segment S B has a value of 68 ° tuned to the light curve 3.
  • a filter wheel 6 with two red , two blue and two green filters application.
  • the filters are preferably arranged in the order of red, green, blue, red, green, blue.
  • the sizes of the individual color filter segments can be the same (60 ° for all six filters) or different, matched to the light curve used 3.
  • the filter wheel can alternatively consist of only one red, one blue and one green filter.
  • the light curve 3 according to FIG. 15E comprises a periodic sequence of a segment S B associated with the color blue, a segment S R associated with the color red and a segment S G which is associated with the color green.
  • Each segment S R , S G , S B has a duration of approximately 1500 ⁇ s.
  • the time interval t B , the time interval t R and the time interval t G which are assigned to the respective segment S R , S G , S B , therefore have the same length.
  • the light curve 3 in each case has a constant value.
  • the light curve 3 has a value of about 95%, during the time interval t R a value of about 100% and during the time interval t G a value of about 110%.
  • the light curve 3 according to FIG. 15F shows, by way of example, short time intervals t B 2, t B 3, t R 2, t G i, t G 2, t G 3 at the end of each segment S R , S G , S B , similar to those already described above in connection with FIG. 15A.
  • the light curve 3 is in turn composed of a periodic sequence of a segment S B , which is associated with the color blue, a segment S R , which is associated with the color red and a segment S G , which is associated with the color green together.
  • the time interval t B , t R , t G of each segment is divided here into three time intervals of a long time interval ti B , t iR , ti G at the beginning of each segment S R , S G , S B and two short time intervals t B 2, t B 3, t R 2, t G i, t G 2, t G 3 respectively to the end of each segment S R , S G , S B.
  • the short time intervals t B 2, t B 3, t R 2, t Gi, t G 2, t G 3 the light flux of the light curve 3 and thus the alternating current through the gas discharge lamp are lowered stepwise.
  • the segment S B associated with the color blue is described here.
  • the light curve 3 is a value of about 110%.
  • the light curve 3 is a value of about 55%, while the value of the light curve 3 in the subsequent to the time interval t B 2 time interval t B 3 to approx 30% is lowered.
  • the time interval t B i has a duration of approximately 1300 ⁇ s, while the time intervals t B 2 and T B 3 each have a duration of approximately 10 ⁇ s.
  • the remaining segments S R , S G of the light curve are constructed identically, as are the segment S B , that of the color blue assigned.
  • the lowering of the light curve 3 during the short time intervals t B2 , t B 3, t R 2, t G i, t G2 , t G 3 serves to improve the color depth of the display system in which the illumination device is used.
  • the light curve 3 according to FIG. 15G shows the two light curve shapes already explained with reference to FIGS. 15E and 15F together in a light curve 3, as can also be used in a lighting device.
  • 15F is here also for the short time intervals t B2, t B3, t R2, t G i, t G2, t G3 of FIG 15G valid, while the levels of the light curve 3 during the long time intervals t B i, t R2, t G 3 each segment S R, S G , S B corresponds to the value according to the light curve 3 of Figure 15E.
  • the amperage-illuminance characteristic of the embodiment of FIG. 16 is approximately linear. It indicates a current in percent on the y-axis and a light level in percent on the y-axis.
  • the amperage-illuminance characteristic curve which can also be stored in the operating device 2 of the lighting device 10, 11, it is possible that with changed lamp operating parameters, such as the current intensity, the brightness of the light source 1, IR, IG, IB of the illumination device 10, 11 is kept at the illumination level predetermined by the light curve 3. Due to the correlation over the characteristic curve, the specification in the light curve can be converted directly into an alternating current for the gas discharge lamp. The different plateuas of the light curve will be thereby converted into respective partial half-waves, wherein the
  • Synchronization specifications of video electronics in the lighting device 10 are selected.
  • the circuit shown in FIG. 17 represents an example of a circuit arrangement 21 for carrying out the method according to the invention, which forms part of the operating device 2.
  • This circuit arrangement 21 is subdivided into the following blocks: power supply SV, full bridge VB, ignition Z, and control section C.
  • the blocks SV, VB, C and Z can be constructed identically as corresponding blocks in conventional circuit arrangements.
  • the power supply regulates the power of the gas discharge lamp, whereby the lamp voltage adjusts.
  • the lamp power with the corresponding lamp voltage is applied to the full bridge, which generates a rectangular lamp power, which is applied to the gas discharge lamp.
  • the Gl is started by means of a Resosnanzzündung through the two lamp inductors L2 and L3 and the capacitor C2, which thus simultaneously form the ignition Z.
  • the embodiment in Fig. 17 is merely exemplary.
  • the control part C which controls the full bridge and the power supply, can be constructed as an analog control, but the control part C is preferably a digital controller, which particularly preferably has a microcontroller.

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

L'invention concerne un procédé pour faire fonctionner une lampe à décharge, cette lampe à décharge fonctionnant au moyen d'un courant de lampe rectangulaire. Selon l'invention, le courant de lampe comprend des points de commutation prédéterminés dans le temps, et une commutation peut se produire au niveau de ces points de commutation pour générer un profil de commutation. Cette invention concerne également un appareil électronique comprenant un appareil d'allumage, un onduleur, et un circuit de commande, ledit appareil électronique exécutant ledit procédé. L'invention se rapporte en outre à un projecteur équipé d'un appareil électronique, ce projecteur étant conçu pour projeter une image pendant que le procédé est exécuté, sans qu'il soit nécessaire de regarder l'image pour effectuer ledit procédé.
EP10700722A 2009-01-27 2010-01-05 Procédé et appareil électronique pour faire fonctionner une lampe à décharge, et projecteur Withdrawn EP2382846A2 (fr)

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DE102009006339A DE102009006339A1 (de) 2009-01-27 2009-01-27 Verfahren und elektronisches Betriebsgerät zum Betreiben einer Gasentladungslampe sowie Projektor
PCT/EP2010/050026 WO2010086191A2 (fr) 2009-01-27 2010-01-05 Procédé et appareil électronique pour faire fonctionner une lampe à décharge, et projecteur

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EP2382846A2 true EP2382846A2 (fr) 2011-11-02

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US (1) US20110310361A1 (fr)
EP (1) EP2382846A2 (fr)
CN (1) CN102301829A (fr)
CA (1) CA2750666A1 (fr)
DE (1) DE102009006339A1 (fr)
WO (1) WO2010086191A2 (fr)

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CN102933010B (zh) * 2011-08-10 2015-04-29 台达电子企业管理（上海）有限公司 放电灯的控制方法、装置及放电灯***
JP5849587B2 (ja) * 2011-10-06 2016-01-27 セイコーエプソン株式会社 プロジェクター及びプロジェクターシステム
DE102011089592B4 (de) 2011-12-22 2019-06-19 Osram Gmbh DLP-Projektor mit Stromüberhöhung, Frequenzmodulation und Stromhöhenmodulation für eine Entladungslampe und entsprechendes Verfahren
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DE102014220780A1 (de) * 2014-10-14 2016-04-14 Osram Gmbh Verfahren zum Betreiben einer Entladungslampe einer Projektionsanordnung und Projektionsanordnung

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CA2750666A1 (fr) 2010-08-05
CN102301829A (zh) 2011-12-28
WO2010086191A2 (fr) 2010-08-05
US20110310361A1 (en) 2011-12-22
DE102009006339A1 (de) 2010-09-16
WO2010086191A3 (fr) 2011-06-23

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