EP2168142A1

EP2168142A1 - High-pressure discharge lamp

Info

Publication number: EP2168142A1
Application number: EP07787567A
Authority: EP
Inventors: Marko KÄNING; Bernhard Schalk; Steffen Franke; Ralf-Peter Methling
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2007-07-16
Filing date: 2007-07-16
Publication date: 2010-03-31
Also published as: US20100213867A1; US8227992B2; CN101743611A; CN101743611B; JP2010533937A; WO2009010088A1

Abstract

The invention relates to a high-pressure discharge lamp, comprising a discharge vessel (1), comprising: electrodes (2), at least one noble gas as the starting gas, at least one element selected from the group of Al, In, Mg, Tl, Hg, Zn for arc transfer and discharge vessel wall heating, and at least one rare-earth halide, which is configured such that the light produced is dominated by molecule radiation.

Description

description

Title: High pressure discharge lamp

Technical area

The present invention relates to a high pressure discharge lamp.

State of the art

High-pressure discharge lamps, in particular so-called HID lamps, have been known for a long time. They are used for various purposes, especially for applications in which a relatively good color rendering and a very good light output are required. These two sizes are usually in an interplay, d. H. an improvement of one size worsens the other and vice versa. In general lighting applications, color reproduction is usually more important, but, for example, in street lighting, it is the other way round.

High-pressure discharge lamps are also characterized by a high compared to the size of the lamp or the size of the light-emitting region of the lamp high power.

Under high-pressure discharge lamps are understood here and in the further only those lamps having electrodes within the discharge vessel. There are a very large number of publications and a huge amount of patent literature on high-intensity discharge lamps, for example WO 99/05699, WO 98/25294, and Born, M., Plasma Sources Sei. Technol., 11, 2002, A55. From the not yet published DE-Az 10 2006 034 833.8 a molecular radiation dominated high pressure discharge lamp is known. However, the problem of a sensitive power dependency of the color difference ΔC (P) with power variation often occurs when the rare earth oxide is selected uncritically. The color difference is also referred to as a chromaticity difference or chromaticity aberration. Small deviations of the power from the operating point with DC = 0 lead to larger ΔC values, which change very steeply from positive to negative values with increasing power or vice versa.

Presentation of the invention

The object of the present invention is to provide a molecular radiation dominated high-pressure discharge lamp, which is characterized by good color rendering over a wide power range. An additional object is to achieve the highest possible efficiency of such a lamp.

This object is achieved by the characterizing features of claim 1.

Particularly advantageous embodiments can be found in the dependent claims.

The aim of the present invention is to provide a high-pressure discharge lamp which is improved with regard to a good overall combination of luminous efficacy and color rendering properties, which is distinguished, in particular, by high consistency of color rendering and by slight chromaticity deviation over a wide performance range. It has been found that this is specifically targeted by grain At least two groups of rare earths can be obtained as a component of the filling, the first group having the property that, when the power P of the lamp is increased within a predetermined power interval, the color difference DC (P) decreases as the power increases the second group has the property that when the power P of the lamp is increased in this predetermined power interval, the color distance DC (P) increases as the power increases, so that a suitable combination of representatives of both groups contributes a flat progression of the color separation DC (P) Increased performance close to zero. The change in power can be seen, on the one hand, from the point of view of dimming and, on the other hand, in terms of the variation of power in a larger ensemble of lamps and their range of characteristics.

The invention is directed to a high-pressure discharge lamp with a discharge vessel, which contains electrodes, at least one noble gas as starting gas, at least one element selected from the group consisting of Al, In, Mg, Tl, Hg, Zn for sheet transfer and discharge vessel wall heating and at least one rare earth halide for the generation of radiation, which is designed so that the generated light is dominated by molecular radiation.

Preferred embodiments are specified in the dependent claims and are also explained in more detail below. The invention relates in particular to a lighting system from the high-pressure discharge lamp together with a matching electronic ballast for their operation. -A-

The basic idea of the invention, as explained in DE-Az 10 2006 034 833.8, is to utilize the radiation generated by molecules in the discharge medium in a strongly dominant manner in the light generation of the high-pressure discharge lamp. For this purpose, the rare earth halide is intended for the generation of radiation, whereby naturally also other components of the discharge plasma can be involved in the radiation generation.

Conventional high pressure discharge lamps are dominated by atomic radiation. Molecular radiation occurs conventionally subordinate and has a broadband spectral distribution compared to atomic radiation, so it can completely fill wider wavelength segments with radiation. In contrast, atomic radiation is inherently linear radiation, but in conventional lamps a certain improvement in the fundamentally limited color rendering properties of line illumination has been achieved by a large number of lines and different broadening mechanisms. In general, however, the segments produced by such mechanisms are significantly smaller than those of molecular radiation and, moreover, the linewidths of atoms are tightly correlated with other particle densities in a complex manner, and it is very difficult to influence particle densities in the lamp.

At the same time, the emphasis on molecules for the radiation budget of the lamp has the effect of enabling good absorption properties and thus greater thermalization. The term thermalization is to be understood locally. One speaks of the local thermo- dynamic equilibrium, because, of course, no homogeneous temperature distribution exists.

The lamp has a noble gas or noble gas mixture as a starting or buffer gas, wherein the noble gases Xe, Ar, Kr, and including very particularly Xe, are preferred. Typical Kaltfüllpartialdrucke the starting gas are in the range of 10 mbar to 15 bar and preferably between 50 mbar and 10 bar, more preferably between 500 mbar and 5 bar and most preferably between 500 mbar and 2 bar. Further, a Bogenübernahme- and vessel wall heating component is provided which has at least one element selected from the group consisting of Al, In, Mg, Tl, Hg, Zn. These elements can be present as halides, in particular iodides or bromides, and also be introduced in this form, for example as AlI ₃ or TlI. The start and buffer gas provides the cold start capability and ignition of the discharge. After sufficient heating, the chemical transfer or, in the case of Al, Mg, In, Hg and Zn, possibly also elementarily present arch transfer and vessel wall heating elements. The corresponding chemical components in the resulting plasma take over. As a result of the altered plasma properties, the wall temperature increases, with which also the at least one rare earth halide passes into the vapor phase. This rare earth halide is preferably formed with one of Tm, Dy, Ce, Ho, Gd, preferably Tm, Dy, and most preferably Tm. These are, as above, preferably iodides or bromides. An example is TmI ₃ . The components that are important for the startup process, ie the start gas and the sheet transfer and vessel wall heating elements may now play only a minor role in the radiation.

In contrast to conventional high-pressure discharge lamps, an arc is now formed that is dominated by the molecular emission of, in particular, the rare earth halides. In particular, thulium monoiodide TmI comes into consideration, which forms from the charged triiodide TmI ₃ .

In principle, rare earth elements can be introduced in particular as triiodides, which become temperature-dependent to diiodides and finally monoiodides. Particularly effective for the invention are the temporarily formed rare earth monoiodides or general monohalides.

The role of the rare earth halides is not limited to the generation of the desired continuous radiation. They simultaneously serve for arc contraction, that is for the reduction of the temperature in the contraction regions and corresponding change in the ohmic resistance of the plasma.

Conventional high pressure discharge lamps traditionally differentiate between so-called voltage formers and photogenerators. The addition of a special stress generator is not absolutely necessary in the present context and can, at least from certain amounts, be counterproductive. Due to the special design of the temperature profile in the form of the contracted arc, apparently species already contained in the discharge core take on suitable resistance formation of the plasma. In particular, the classical stress formers Hg and Zn can also be dispensed with in whole or in part, the invention not being limited to Hg- or Zn-free Lamps is restricted. To omit or at least reduce the component Hg is a clear advantage from an environmental point of view.

However, the components Hg and Zn may also play a positive role in connection with wall interactions, for example, or may be desirable for further increasing the lamp voltage and, therefore, be included despite the actual dispensability of a voltage generator.

In order to achieve very good radiation yields, it was conventionally customary to resort to atomic radiation, in particular that of Tl and Na. The necessity of using atomic radiation to achieve high light efficiencies is not only not necessary in the present context, but because of the color rendering properties, in the case of Tl and Na especially because of the unwanted arc cooling, also not desirable. In particular, the introduction of Na should be omitted completely or be significantly limited. The Na radiation in the infrared at about 819 nm and further infrared lines of Na, the plasma because it is above a cut-off wavelength, for example above about 630 nm, often optically thin, leave largely unhindered and cool the arc. Even if the spectral range around the Na resonance line at 589 nm can not be described as optically thin, this radiation would also lead to unwanted cooling of the central arc regions. This would cause the temperatures in the arc to drop in an undesirable manner. An analogous argumentation also applies to other species which have significant emission capabilities in the wavelength range above 580 nm, in particular K and Ca. The constituents Na, K and Ca should thus preferably be present at most in amounts which are not relevant for the radiation properties and do not disturb the aforementioned domination by molecular radiation.

According to the invention, the plasma should be optically thick over as wide a visible spectral range as possible. This means that, compared to conventional high-pressure discharge lamps, there is further thermalization of the radiation before it leaves the lamp, which produces a desired proximity to a Planck-like spectral distribution. Planck's spectral distribution corresponds to the idealized blackbody and is perceived as "natural" in human sensory perception.

Incidentally, the pronounced contributions to radiation of the additions Na, K and Ca "bend" the spectra and worsen the proximity to Planck's spectral behavior. However, lines at wavelengths above 600 nm are basically hardly avoidable, because here the rare earth halides no longer appreciably absorb and no other absorber is available.

The proximity to Planck's radiation behavior can be measured with the so-called chromaticity difference ΔC. The lamp according to the invention should have a good, ie small, ΔC value. When using ceramic discharge vessels, very advantageous values of ΔC I <10 ^"2 can be achieved here for general illumination purposes. With the high-pressure discharge lamp according to the invention, good luminous efficiencies can be achieved, preferably over 90 lm / W. At the same time, the color rendering properties should be good, preferably with a color rendering index Ra of at least 90.

In individual cases, in the embodiment of the invention, one of the two objectives mentioned above, the color rendering properties or the luminous efficacy, can clearly be in the foreground, such as the luminous efficacy in street lighting. However, the preferred area of application of the invention is the high quality general lighting, which ultimately depends on both sizes.

The domination by molecular radiation is quantified in one embodiment of the invention by a parameter AL, which is referred to herein as "atomic fraction". Claim 12 specifies the determination of this atomic fraction AL. It is preferably at most 40%, better 35%, 30% or even at most 25%, even in quartz discharge vessels. For ceramic discharge vessels, it is more preferably at most 20%, better 15% and even at most 10%.

The particular stability with variation of the performance is achieved by suitably combining several rare earth halides as molecular strands. Two groups of rare earth halides are used together. A first group has the property that small deviations of the power from the operating point with ΔC = 0 lead to larger ΔC values, which change steeply from positive to negative values with increasing power. One Particularly suitable representatives of this group is Tm halide, in particular TmJ3. A second group has the property that small deviations of the power from the operating point with Δ = 0 lead to larger ΔC values, which change rapidly from negative to positive values with increasing power. A particularly suitable member of this group is Dy-halide, especially DyJ3. Another well-suited member of this group is GdJ3, which in particular can be used in addition to Dy halide. Particularly suitable is a mixture which contains about equal molar amounts of ers ^¬ ter and second group, in particular 25 to 75 mol% of the first group. Particularly preferred is a proportion of 45 to 55 mol .-% of the first group.

The favorable properties of a lamp according to the invention can be exploited and optimized especially in connection with an electronic ballast, which is why the invention also relates to a lighting system comprising a lamp according to the invention with a suitable electronic ballast.

Brief description of the drawings

FIG. 1 shows a schematic sectional view of a high-pressure discharge lamp according to the invention with a ceramic discharge vessel.

FIG. 2 shows a schematic sectional view of a high-pressure discharge lamp according to the invention with a quartz glass discharge vessel. FIG. 3 shows a circuit diagram with an electronic ballast and a lamp according to FIGS. 1 and 2.

FIGS. 4 to 6 show emission spectra of the lamps from FIGS. 1 and 2.

FIG. 7 shows a diagram of the spectral eye sensitivity curve.

FIG. 8 shows the emission spectrum from FIG. 4 in comparison with a Planck curve.

Figure 9 shows different in six individual diagrams

Characteristics of the lamp of Figure 1 depending on the lamp power.

Figure 10-11 shows the chromaticity aberration and color temperature as a function of the lamp power for different fillings.

FIG. 12 shows the radiation spectrum of two fillings.

Figure 13-16 shows chromaticity aberration and color temperature as a function of lamp power for a series of rare earths.

FIG. 17 shows the emission spectrum of a high-pressure discharge lamp with Tm / Dy mixture.

Figure 18-19 shows the radiation spectrum for two lamps according to the prior art. Preferred embodiment of the invention

FIG. 1 and FIG. 2 show schematic sectional views of high-pressure discharge lamps according to the invention. FIG. 1 shows a lamp with a discharge vessel 1 made of Al 2 O 3 ceramic. The current flow through the arc discharge is made possible by tungsten electrodes 2 which are mounted in the discharge vessel on both sides and which are introduced into the discharge vessel via a feedthrough system 3. For example, the feedthrough system is made of molybdenum pins and is welded to the electrode as well as to the external power supply (not shown in the figure).

FIG. 2 shows a lamp with a discharge vessel 10 made of quartz glass. The tungsten electrodes 2 are here welded to a molybdenum foil 13. In the region of this film, the quartz glass discharge vessel is sealed by a pinch. The molybdenum foils are also welded to the respective outer power supply 4.

The characteristic dimensions of the discharge vessels are the length 1, the inner diameter d and the elec- trode distance a, which will be discussed later.

Both the ceramic and the quartz glass discharge vessel are each introduced into an outer bulb of quartz glass, not shown, as known per se. The outer bulb is evacuated. From the outer bulb, the current feeds are brought to the outside via pinches that tightly close the outer bulb and serve to connect the lamp to the electronic ballast (ECG). This generates from the mains voltage the square wave typical for the operation of high-pressure discharge lamps. excitation with a frequency of typically 100 Hz to 400 Hz at a power of 35 W to 400 W ("alternating DC voltage"). FIG. 3 shows a basic circuit diagram with the mains voltage briefly referred to as AC, the electronic ballast designated as electronic ballast and the lamp.

The discharge vessel contains a filling with Xe as starting gas and AII3 and TlI as sheet transfer and wall heating elements as well as TmI ₃ .

The quantities and the characteristic dimensions of the discharge vessel vary depending on the design of the lamp.

Typical examples A1 to A6 are listed in Table 1. The specified Xe pressure is the cold fill pressure. The indicated iodide amounts are the absolute amounts added. Also, the above geometry parameters 1, d, a are listed. The specification Δ C is given in thousandths (E-3).

Preferably, the electronic ballast can be designed to excite acoustic resonances by impressing a high-frequency amplitude modulation in a frequency range of approximately between 20 and 60 kHz. For a more detailed explanation, reference is made by way of example to the patent EP-B 0 785 702 and the references given therein. Excitation of acoustic resonances in this form leads to active stabilization of the discharge arc in the plasma, which may be advantageous in particular in connection with the present invention because of the relatively narrowed shape of the temperature profile.

Table 1 The last four columns of Table 1 are discussed in more detail below.

First, radiation spectra of the lamps will be illustrated for the embodiments A1, A2 and A3. It also explains the determination of the atomic content AL. FIGS. 4, 5 and 6 each relate to the exemplary embodiments A1, A2 and A3 and each show a spectrum of the radiation of the lamps from FIG. 1 measured with a spectral resolution of 0.3 nm after 10 h of operation in an integrating sphere or Figure 2 in the visible range between 380 nm and 780 nm. The vertical axis shows the spectral power density I in mW / nm.

Superimposed on the resolution corresponding to the serrated line is a curve determined in accordance with the following procedure for the determination of the continuous background. In particular, reference is made to the additional graphic explanations in FIG. 5. From the measurement, there is a curve I _m (λ). In an interval with the total width 30 nm around each wavelength value λ corresponding to a measurement, ie with 50 measured values to the respective sides, each wavelength value is assigned a minimum I _hl (λ) in this interval. In this way, a smoothed function I _hl (λ), which basically runs under the measured spectral distribution I _m (λ), is given.

Based on this, a further function I _h2 (λ) is determined, again using intervals of the same width around each individual wavelength value, ie with a total of 100 measuring points. In each case, however, the maxima of the function I _h i (λ) are in this Inter- vallen as function values I _h 2 used. The result is a second function, which comes a little closer to the measured curve, that is, runs between the measured curve I _m (λ) and the function I _h i (λ) with the minima.

Based on this, a third function I ₁₁ (λ) is determined, again determining the mean values of Ih2 (λ) in the 30 nm width intervals around the respective wavelength values. This clearly smoothes the curve I _h 2 and, in this example, leads to the smooth lines drawn in FIGS. 4 to 6.

Basically, this is an exemplary and relatively simple procedure for the determination of a realistic continuous background, which however is objective and reproducible. With the determined subfunction I ₁₁ (λ) and the measured spectral distribution I _m (λ), the atomic component AL can then be determined as: v (λ) I _m (λ) dλ-v (λ) I _u (λ) dλ

AL = _ o

The light-adapted sensitivity of the human eye is taken into account as a weighting function and at the same time limits the integration to the visible spectral range. The spectral eye sensitivity V (λ) is shown in FIG. 7.

In order to determine the individual steps for determining I _h i (λ), I _h 2 (λ) and I ₁₁ (λ) as shown with the full interval width of 30 nm, measured values below 380 nm and above 780 nm are also necessary at the edge of the wavelength range.

By weighting with the eye sensitivity V (X), which is equal to zero outside the wavelength range 380 nm to 780 nm, however, it is sufficient to determine the average line component AL to carry out the measurement only between 380 nm and 780 nm. When determining I _h i (λ), Ih2 (λ) and I ₁₁ (λ), the interval size for the individual steps may then be limited to the range present in the measured values. For determining the value of I _hl (390 nm), I _H2 (390 nm) and I ₁₁ (390 nm), the interval width of 30 nm interval corresponding, for example, not 375 nm used to 405 nm, solar countries only the interval of 380 nm to 405 nm.

As can be seen, for example, in FIG. 4 at 535 nm, absorptions caused by atomic lines (in this case the Tl line at 535 nm) may result in deep break-ins in the continuous molecular radiation. These occur in such close proximity Wavelength range that they do not affect the positive properties of the continuous molecular radiation, such as the good color rendering. However, the higher the spectral resolution is in the measurement of I _m (λ), the lower and higher the number of these burglaries become.

If these burglaries are closer than the interval width of 30 nm, this is determined in the manner mentioned

Underground curve I ₁₁ (λ) falsely pulled down. To prevent this, the spectral resolution in the measurement of I _m (λ) to the range of 0.25 nm to 0.35 nm.

The upper limit results from the necessity of selecting the resolution so high that the atomic lines can be dissolved at all.

If measured with a spectral resolution higher than 0.25 nm, the measurement I _m (λ) before the determination of I _h i (λ), Ih2 (λ) and I ₁₁ (λ) must be at a spectral resolution within the limit of 0 , 25 nm to 0.35 nm. This can be done for example by averaging over several adjacent measuring points.

Illustratively speaking, the atomic fraction component integrates the part of the measurement curve remaining above the background curve constructed as described above. It measures a relative area ratio to the area under the measurement curve as a whole.

In the present embodiments, the a-tomlinienanteile 4% for the ceramic lamps according to the embodiments Al and A2 and 12% for the quartz lamp according to embodiment A3. It thus turns out that as a result of the molecular dominance according to the invention, a relatively very large continuous background exists in the radiation, which has strongly suppressed the relative importance of atomic line emission.

FIG. 8 shows the measurement curve I _m (λ) from FIG. 4 together with a superimposed Planck curve (shown in dashed lines) for a black radiator with the temperature 3320 K. It can be seen that the spectrum behaves very similar to Planck up to the red wavelength range of just over 600 nm. Quantitatively, this means a size of the Farbartunterschieds .DELTA.C of 3 x 10 ^{~. 4} The luminous efficacy was 94 lm / W at a color rendering index of Ra = 92. Thus, this embodiment is perfectly suitable for general lighting.

FIG. 9 shows, in six individual diagrams, various characteristic data of the exemplary embodiment of the lamp Al from FIG. 1 as a function of the lamp power in each case on the horizontal axis. From left to right, the luminous flux Φ, the color rendering index Ra, the luminous efficacy η and at the bottom from left to right the lamp voltage U and the lamp current I are shown, the bottom points of the right current axis and the top points of the right are assigned to the left voltage axis, the chromaticity difference ΔC and finally the most similar color temperature T _n , ie the temperature of the color-like black radiator. It can be seen that, in particular, the color rendering index and the chromaticity difference are strongly performance-dependent and assume particularly good values at values of 180 W. The light output deteriorates only slightly. Here it is not recommended to go well beyond 180 W. It can thus be seen that high-pressure discharge lamps with unusually good color rendering properties can be produced with the invention, especially with relatively high powers in relation to the size of the discharge vessel.

In addition, reference is made to the size "chromaticity difference ΔC" in the CIE Technical Report 13.3 (1995). It works to assess the quality of the light color of a lamp with regard to a perceived as "natural" sensory perception by humans. The color difference is a measure of the proximity of the lamp spectrum to Planck's radiation behavior up to a color temperature of 5000 K or to daylight spectra above this limit. There are fields of application in which large values of Farbartunterschieds are not disturbing, however, should preferably have a Farbartunterschiedswert with an amount of less than 10 ^{~ 2} better than 5 x 10 ^-3 and even better than 2 for more demanding lighting tasks, for example in general lighting the lamp of the invention x 10 ^{~ 3} .

The components mentioned in the exemplary embodiment are exchangeable by alternatives within the scope of the teaching of this invention; for example, Xe can very well be replaced in whole or in part by Ar or Kr or a mixture of noble gases. For example, AlI ₃ can be replaced by InI ₃ , InI or MgI ₂ , again in whole or in part. The rare earth halide TmI ₃ can also be replaced, in particular by CeI ₃ or else by other rare earth iodides or bromides or mixtures.

It is an advantage of the invention to be able to dispense with components such as Hg. However, these can also be included. On the already mentioned pronounced

Radiation contributions of Na, K and Ca should preferably be omitted entirely or at least to the extent that the criterion described remains dominant for the dominance of the molecular radiation. The embodiment contains a small amount of thallium iodide TlI. Tl is conventionally used to increase the efficiency due to its resonance line at 535 nm. Figures 4 to 6 show that this makes no significant contribution to the radiation. The function of the TlI consists here only in the sheet transfer and an additional sheet stabilization. In this respect, care must be taken with this component, as Tl also has lines in the infrared and acts there similar to Na, K or Ca.

The conditions in the lamp should therefore be designed so that the atomic line emission in a broad spectral range of the continuum in the visible does not play a significant role, the plasma is therefore substantially optically thick in this wavelength range for this radiation or this radiation to a lesser extent is produced. At the same time, the molecular emission of rare earth halides, in particular monohalides, from the plasma should be maximally promoted, in particular by minimizing arc cooling by radiation in the spectral region in which the plasma is no longer sufficiently optically thick , In the present embodiment, this spectral range extends from 380 nm to about 600 nm and is thus relatively large. However, such large areas are not mandatory.

Commercial lamps show line shares of well over 20%. An example is shown in FIG. 18. This is a lamp with a ceramic discharge vessel of the type HCI-TS WDL 150W (manufacturer OSRAM), which spectrally illuminates in an integrating sphere after ten hours of burning time. was measured. This results in a value AL of 35% atomic content. FIG. 10 shows the already described constructed curve for the underground.

Another high-pressure discharge lamp with ceramic discharge vessel of the type CDM-TD 942 150W (manufacturer Philips) with spectral distribution according to FIG. 19 shows an AL value of 37%.

In a particularly preferred embodiment, the realization of a molecular radiation-dominated preferably Hg-free high-pressure discharge lamp is described below, which is characterized by good efficiency and color reproduction over a wide power range.

So far, it has been shown that the sole use of, for example, the TmI ₃ as a molecular radiator a relatively sensitive performance dependency of the color distance .DELTA.C accepts. Small deviations of the power from the operating point with ΔC = 0 lead to larger ΔC values, which change very steeply from positive to negative values with increasing power. A similar behavior can be found in other rare earths. By contrast, the use of DyI ₃ , for example, leads to a ΔC (P) characteristic, in which ΔC crosses from negative values to positive values with increasing power - in contrast to the characteristic of TmI ₃ . A similar dependence results for the color temperatures T _n (P). Spectra of the lamps each containing TmI ₃ or DyI ₃ in the vicinity of the so-called. Operating point (.DELTA.C <2E-3) are shown in Figure 12 by way of example. In Figures 10 and 11 are the Characteristic curves for ΔC and T _{n are} shown. The area of the operating point is shown in dashed lines.

Further exemplary embodiments are shown in FIGS. 13 to 16. These are in each case a high-pressure discharge lamp with a ceramic discharge vessel based on a filling with 1 bar of Xe, 2 mg of A1J3, 0.5 mg of TlJ and a halide of a rare earth metal. Shown is the behavior of the rare earth metals CeJ3, PrJ3, NdJ3, GdJ3, DyJ3, TmJ3, YbJ2, and HoJ3. FIG. 16 illustrates that, as representatives of a first group in which the chromaticity aberration ΔC decreases with increasing power, above all Tm and Ho come into question because they reach values of ΔC close to zero in sections or also have a flat gradient in sections. Further representatives of this group are shown in FIG. These are in particular Pr, Ce and Nd, as well as Yb. As a representative of a second group in which the chromaticity softening ΔC increases with increasing power, above all Dy and Gd come into question, see FIG. 16. The associated color temperature (in Kelvin) is shown in FIGS. 13 and 14.

Concrete embodiments relating to H0I ₃ and GdI ₃ , are illustrated in Figures 10 and 11. The high-pressure discharge lamp with ceramic discharge vessel has as filling 1 bar Xe, 2 mg A1J3, 0.5 mg TlJ and 4 mg HoJ3 (example rhombus) and based on a filling with 1 bar Xe, 2 mg A1J3, 0.5 mg TlJ and 4 mg GdJ3 (example star). Indicated are ΔC (P) near zero (ΔC in units of 10 ^~3 ), see Figure 10, and the color temperature Tn (in K), see Figure 11. Both magnitudes are in the range 50 to 50 as a function of power (P) 300 W indicated. Both iodides show a flat course of the Color difference ΔC (P) at power variation. When using HoJ3 alone, the color temperature is particularly constant as a function of the power variation.

A suitable combination of TmI ₃ and DyI ₃ is particularly preferred because it allows to set the performance dependency of ΔC and T _n specifically with particularly high efficiency. A suitable combination is advantageously a mixture containing 25 to 75 mol .-% TmI ₃ , remainder DyI3. Particularly preferred is a proportion of 45 to 55 mol .-% TmI ₃ . a concrete example with a 1: 1 mixture is shown in FIG. 10 with respect to the chromaticity aberration ΔC and in FIG. 11 with respect to the change of the color temperature. Another good example is the use of TmI3 and HoI3 together with DyI3.

A suitable combination of these two groups of molecular radiators leads to spectra characterized by a particularly flat profile of ΔC (P) close to zero (ΔC <2E-3), as shown in FIGS. 15 and 16. A yield of more than 80 lm / W, a color rendering of Ra> = 95, a good red reproduction with R9 = 74-95 and a color temperature, T _n , of about 3500 K can be achieved over a power variation of almost 1: 2 , see Figures 13 to 14. Figure 17 shows the radiation spectrum of a high pressure discharge lamp with Tm / Dy mixture as specifically described in Figures 10 and 11.

The most important parameters of the cylindrical ceramic discharge vessel used for the embodiment (see FIG. 1) are the inner diameter (d = 9.1 mm) Inner length (1 = 13 mm) and the electrode distance (a = 10 mm).

The fillings of the lamps all contained 1 bar Xe (cold fill pressure), 2 mg AII ₃ and 0.5 mg TlI. In addition, 4 mg TmI ₃ , 4 mg DyI ₃ and 2 mg TmI ₃ + 2 mg DyI ₃ were added to the lamps as dominating molecular radiators. Instead of DyI ₃ or in addition to DyI ₃ GdI ₃ may preferably be used.

Claims

Expectations

1. High-intensity discharge lamp with a discharge vessel

(1), which contains:

- electrodes (2),

- at least one noble gas as starting gas, - at least one element selected from the group consisting of Al, In, Mg, Tl, Hg, Zn for arc transfer and discharge vessel wall heating and

- at least one rare earth halide for radiation generation, which is designed so that the light generated is dominated by molecular radiation, characterized in that at least one representative from a first group of rare earth halides is used together with at least one representative from a second group of rare earth halides, wherein the first group has the property that when the power P of the lamp is increased in a given power interval, the color difference ΔC(P) decreases when the power is increased, and the second group has the property that when the power P of the lamp increases in this Given the specified power interval, the color difference ΔC(P) increases when the power is increased.

2. High-pressure discharge lamp according to claim 1, in which the noble gas is at least one noble gas selected from the group consisting of Xe, Ar, Kr.

3. High-pressure discharge lamp according to claim 2, in which the cold filling partial pressure of the noble gas is between 500 mbar and 5 bar.

4. High-pressure discharge lamp according to one of the preceding claims, in which at least one element is selected from the group of Al, In, Mg as the arc transfer and discharge vessel wall heating element.

5. High-pressure discharge lamp according to one of the preceding claims, in which the first rare earth halide contains at least one element selected from the group consisting of Tm, Ho, Ce, Pr, Nd.

6. High-pressure discharge lamp according to one of the preceding claims, in which the second rare earth halide contains at least one element selected from the group consisting of Dy, Gd.

7. High-pressure discharge lamp according to one of the preceding claims, in which no amount of Na relevant to the radiation properties is contained in the discharge vessel (1).

8. High-pressure discharge lamp according to one of the preceding claims, in which no amount of CaI ₂ or K relevant to the radiation properties is contained in the discharge vessel (1).

9. High-pressure discharge lamp according to one of the preceding claims, in which the discharge vessel (1) consists of ceramic and the following applies to the chromaticity difference ΔC:

I ΔC I < 10 ^"2 .

10. High-pressure discharge lamp according to one of the preceding claims, in which the luminous efficacy η applies: η > 90 lm/W.

11. High-pressure discharge lamp according to one of the preceding claims, in which the color rendering index Ra applies: Ra > 90.

12. High-pressure discharge lamp according to claim 4 or 5, in which the arc transfer and discharge vessel wall heating element and / or the rare earth element was filled in the form of an iodide or bromide.

13. High-pressure discharge lamp according to one of the preceding claims, in which the following applies to the atomic line component AL: AL <40%, whereby the following applies:

OO OO

where: V(λ) is the light-adapted eye sensitivity of the human eye,

I _m (λ) is the spectral intensity distribution of the high-pressure discharge lamp measured during a measurement in an integrating sphere with a resolution between 0.35 nm and 0.25 nm or, in the case of a higher measurement resolution, converted to a resolution in this range by averaging and I ₁₁ (λ) is a model function approximating the continuous background of the measured intensity curve I _m (λ), which is determined by

1. Determine a function I _h i (λ) with the minima of I _m (λ) present in intervals of width 30 nm around the respective wavelength value,

2. Determine a further function I _h 2 (λ) with the maxima of Ihi (λ) and present in the intervals of width 30 nm around the respective wavelength value

3. Determine the function I ₁₁ (λ) with the respective arithmetic mean values of I _h2 (λ) present in the intervals of width 30 nm around the respective wavelength value.

14. High-pressure discharge lamp according to claim 13, in which the discharge vessel (1) consists of ceramic and the following applies to AL: AL <20%.

15. High-pressure discharge lamp according to claim 13, in which the discharge vessel (1) consists of quartz glass and the following applies to AL: AL <30%.

16. Lighting system with a high-pressure discharge lamp according to one of the preceding claims and an electronic ballast for operating the high-pressure discharge lamp.