EP1684005A1 - Single ended high-pressure discharge lamp - Google Patents

Abstract

The contour (35) of a reflector (2) has a first zone which reflects back at least 90 percent of light incident on it at positive angles in relation to a lamp axis, and a second zone which reflects back at least 90 percent of light incident on it at negative angles in relation to the lamp axis. An inner discharge vessel (7) contains a metal halide filling. The lamp (1) has a specified average color temperature.

Description

Technical area

The invention relates to a single-ended high-pressure discharge lamp according to the preamble of claim 1. These are, in particular, high-pressure discharge lamps, preferably metal halide lamps, but also, for example, halogen incandescent lamps. Frequently, an elongated, in particular ceramic, discharge vessel is used as lamp bulb.

State of the art

EP-A 1 109 199 describes a single-ended high-pressure lamp, in which the outer bulb is surrounded by a reflector. The reflector contour is not further subdivided.

The disadvantage of this is that it can come in the use of metal halide in these conventional reflectors to color effects in the figure, due to the filling condensate, which usually deposits down in the burner of the lamp. This effect occurs particularly clearly in a horizontal burning position, whereby the condensate acts like a color filter and is imaged by a conventional reflector as a "yellow spot" with significantly lower color temperatures in the upper half of the projection plane.

From DE 38 08 086 a reflector is already known, whose contour consists of different shaped sections that represent partially free-form surfaces. This reflector is designed for use in vehicle headlights together with incandescent bulbs. The concept of the open space contours is for example explained in detail in EP-A 282 100.

Presentation of the invention

It is an object of the present invention to provide a single-capped lamp according to the preamble of claim 1, which avoids color effects as possible.

This object is solved by the characterizing features of claim 1. Particularly advantageous embodiments can be found in the dependent claims.

In the usual reflectors only positive angles are generated. This means that in relation to the lamp axis or its parallel, one has only beams reflected back from the reflector contour which form positive angles with the axis, ie intersect the axis in the far field again.

Dividing the reflector lamp in the lateral section into four quadrants, which are formed by the lamp axis and the reflector opening, the quadrants are always assigned crosswise in a conventional reflector. In the case of a horizontal burning position, this means that light from the lower half, as defined by the second quadrant, in the imaging plane irradiates the opposite half, by definition the fourth quadrant. Conversely, light from the upper half (first quadrant) of the lamp is assigned in the lower half plane of projection, alo the third quadrant. However, this unique assignment causes a high color spread in lamps that have a condensate as a filling. Because the area containing the condensate, so usually always the lower quadrant in the horizontal burning position, receives its radiation only on the detour through the condensate, which turns the radiation yellowish and thus creates a stain with lower color temperature. The area that contains no condensate, so usually always the upper quadrant in a horizontal burning position, receives its radiation without any change, here the color temperature is much higher. In conventional measurements in an integrating sphere, this problem is not indicated, because there the measurement is made integrally over the entire sphere and not spatially resolved.

According to the invention, the reflector is now contoured such that both zones receive approximately half of the light of each quadrant. In practice, it should be at least 35% instead of the optimal 50%. The first zone is calculated to send the light into the quadrant, which is directly above it, without the lamp axis to cut. Only the second zone is calculated so that its assigned light intersects the lamp axis in the usual way and falls in the other quadrants of the projection plane. In this way an averaging is achieved. Each half of the radiation in one quadrant of the projection plane originates from the underlying quadrant of the emission side, the other half from the opposite quadrant of the emission side. This balancing effect had previously been laboriously and imperfectly achieved by a suitably structured cover.

In particular, the single-ended lamp has a vacuum-sealed inner vessel, in particular an elongate discharge vessel made of ceramic or quartz glass, which u.U. is still housed in an outer bulb. It does not matter if the discharge vessel is cylindrical or rounded.

The inner vessel is still surrounded by a reflector. Preferably, the inner vessel is a structural unit discharge vessel with outer bulb. This is particularly preferably a ceramic discharge vessel, in particular a metal halide lamp for general lighting purposes.

Here, a base with electrical connections on the one hand carries the inner vessel and on the other hand, the reflector part. The electrical connections are normally connected to power supply lines which make electrical contact with a light source inside the inner vessel, which are realized, for example, by electrodes in the interior. Without limiting the invention, external electrodes may also be used, or an electrodeless configuration. Instead of a ceramic discharge vessel, a discharge vessel made of quartz glass or hard glass can also be used. An outer bulb as part of the inner vessel is not essential, but often desirable.

The base has, in addition to the base stone on a conventional, the socket facing part, for example, a screw base approach or bayonet socket approach or GU socket.

Preferably, the inner vessel, so for example, the lamp envelope or the outer bulb, which contains a discharge vessel, or the discharge vessel in the case the absence of an outer bulb, held in the central opening by means of a spring clip, as known per se.

Usually, power leads are led out of the lamp bulb, which are connected to the electrical terminals of the base. A particularly flexible and time-saving solution is to use for the connection between the electrical connections and the power supply terminals clamping connections, as is known.

Usually, the base also has a barrel-facing part, which is at least partially connected as known per se by crimping with the base brick. This part contains, for example, a conventional screw thread or pin of a bayonet socket etc.

A typical application is a metal halide lamp containing a filling with or without mercury content, possibly with inert starting gas, preferably noble gas.

Brief description of the drawings

Figur 1

eine Metallhalogenidlampe in Seitenansicht;

Figur 2

einen Reflektor für eine derartige Lampe;

Figur 3

die Funktionsweise eines früheren Reflektors;

Figur 4

die Definition der vier Quadranten;

Figur 5

die Zuordnung zwischen Reflektorsegment und Ausstrahlungssegment bei einem früheren Reflektor;

Figur 6

die Funktionsweise eines Reflektors gemäß der Erfindung;

Figur 7

die Einteilung der Reflektoröffnung nach Uhrzeiten;

Figur 8

die Streuung der Farbtemperatur über die Projektionsebene bei einem bisherigen Reflektor;

Figur 9

die Streuung der Farbtemperatur über die Projektionsebene bei einem neuartigen Reflektor;

Figur 10

das Überlagerungsprinzip eines neuen Reflektors;

Figur 11

den Strahlengang einer bisherigen (Figur 11a) und neuen ReflektorLampe (Figur 11 b).

In the following the invention will be explained in more detail with reference to several embodiments. Show it:

FIG. 1

a metal halide lamp in side view;

FIG. 2

a reflector for such a lamp;

FIG. 3

the operation of an earlier reflector;

FIG. 4

the definition of the four quadrants;

FIG. 5

the assignment between the reflector segment and the radiation segment in a previous reflector;

FIG. 6

the operation of a reflector according to the invention;

FIG. 7

the division of the reflector opening according to times;

FIG. 8

the dispersion of the color temperature over the projection plane in a previous reflector;

FIG. 9

the dispersion of color temperature across the projection plane in a novel reflector;

FIG. 10

the overlay principle of a new reflector;

FIG. 11

the beam path of a previous (Figure 11a) and new reflector lamp (Figure 11 b).

Preferred embodiment of the invention

FIG. 1 shows a reflector lamp 1 with a reflector part 2 made of aluminum. A pedestal 3 of the lamp has inside a raised collar 4, which is cylindrically shaped and partially surrounds an outer bulb 5, but ends below the discharge volume 6 of the discharge vessel 7. The neck 9 of the reflector is first pushed over the collar 4. Then an attachment by crimping, ie pressing the neck 9 in holes on the collar 4 (not shown) is realized, so that dents result. Sufficient are three distributed over the circumference caused by crimping dents. Instead of through holes also superficial recesses are sufficient.

It is in Figure 1 is a metal halide lamp for general lighting, the filling halides of Na, Sn, Ca, Tm. Tl and similar. may contain. The ceramic inner discharge vessel 7, which is closed on two sides, is arranged longitudinally in the lamp axis A. It is closely surrounded by the outer bulb 5, which is squeezed on one side and made of tempered glass. A frame 14 with short and long supply line (only partially shown) holds the discharge vessel 7 in the outer bulb 5. The electrodes 17 in the interior of the discharge vessel are connected via feedthroughs 18 to the supply lines. The latter are in the region of a pinch, which closes the outer bulb 5, connected to external power supply lines. The pinch of the outer bulb is seated in a matching opening of the base 3 of ceramic and is held there by a metal clip, as known per se. The base is essentially formed from the base block 3 and a screw base part 10.

A reflector 2 is externally attached to the outer bulb 5. It is articulated in a section with contour 35, at one end of a neck portion 9 is seated, on which the base is fixed, and at the other end of the reflector opening 36 is seated, which is closed with a simple cover 37.

Figure 2 shows the reflector 2 in magnification. The contour 35 is divided into two zonal layers 38, 39, which are both shaped as free-form surfaces, which are rotationally symmetrical are. The first on the neck 9 attaching zone 38 is flat and has a mean angle to the lamp axis of about 70 °, taking the average value between the beginning and end of the first zone. The second outer zone 39 is steep and has a mean angle to the lamp axis, which is significantly lower by at least 20 °, preferably 30 °, less. Their mean angle to the lamp axis A is about 35 °, taking the mean value between the start and end point of the second zone. The second zone 39 terminates at an enclosure 40 which later holds the cover by being bent inwardly.

The operation of an earlier reflector is shown by way of example in FIG. The local reflector lamp 45 is shown in vertical section at horizontal focal position. A condensate 46 of the charge deposits on the bottom 47 of the discharge vessel 48. The lamp is divided by the lamp axis A into two symmetrical halves. The upper half is the first quadrant AI, the lower half as the second quadrant AIIezeichnet. Radiation escapes downwardly from the discharge vessel 48 from the center of the discharge vessel where the discharge arc is located. It is emitted by definition into the second quadrant AII. The first half of the lamp is defined as in the first quadrant AI First and second quadrant form the emission side, see Figure 4. It ends at the cover 49. Behind the cover screen begins the projection side, in which essentially only the far field interested, such as a at a certain distance vertically arranged projection plane 50. Here are the other two quadrants AIII and AIV. By definition, the third quadrant AIII is spanned between the lower half of the cover plate 49 and the projection plane 50, while the fourth quadrant AIV is above it, that is spanned between the upper half of the cover plate 49 and the projection plane 50. The principle of the quadrant is shown in FIG. 4.

FIG. 3 shows the relationship between emission side and projection side in the prior art. Quadrant AI light (not shown) is reflected in quadrant AIII, while correspondingly light from quadrant AII, where condensate 46 modifies the radiation, is reflected in quadrant AIV. By way of example, two light beams 31, 32 are shown. Light which exits the discharge vessel through the condensate 46 in quadrant AII is irradiated in the plan view of FIG. 5 through the reflector segment a ₁₁ into the emission _segment a _lV in the projection plane, whereby an average color temperature of 3000 K (integrally measured with the Ulbrichtkugel) a radiation segment on the projection plane is created, which has a color temperature of about 2800 K, for example. Analogously, a radiation segment is generated in the lower projection plane, which has about 3200K color temperature, because it comes from the quadrant I without interference from the condensate 46 ,. The color temperature has large local differences caused by condensate and also by fringing. The resulting color effects are usually reduced by a brought into the beam path, structured cover plate 49.

In the case of the color-compensated reflector (FIG. 6), light with a low color temperature, which is located mainly in a reflector segment which lies in the horizontal burning position at the bottom, that is to say at about 6 o'clock (see FIG. 7), ie in the second quadrant BII, both in the fourth Quadrant BIV with positive angles of reflection (symbolized by (+)), as well as in the third quadrant BIII with negative angles (-), thrown.

The representation with time is shown in Figure 7, wherein the reflector opening 11 is marked along the circumference with times. 12 o'clock is up and 6 o'clock, so the direction in which the condensate 46 is located in the discharge vessel is below. Conversely, the same applies to undisturbed light from the first quadrant BI. Again, this is thrown about 50% each in the third (BIII) and fourth quadrant (BIV). Thus, light of low color temperature (reflector segment at 6 o'clock) is mixed with light of high color temperature (reflector segment at 12 o'clock), while light of medium color temperature (reflector segment at 3 o'clock) again with light of medium color temperature (reflector segment at 9 o'clock) on the Projection level 50 is mixed.

In this way, the resulting scattering of the color temperature over the projection plane 50 is greatly reduced compared to a conventional reflector. 8 shows the scattering of the color temperature of a lamp with a conventional simple reflector and FIG. 9 the greatly reduced scattering when using a new reflector 2 composed of two zonal layers 38, 39 according to FIG. 2.

The two zonal layers 38, 39 of the reflector cause a reflector segment b _II (FIG. 10) to form a radiation segment due to its contribution to the flat reflector zone 38 b _III and by its contribution to the steep reflector zone 39 generates a radiation segment b _IV in the projection plane (shown by dashed lines). These two emission segments b _III and b _IV , generated on the emission side by the reflector segment b _II , have, for example, a color temperature of 2800 K at an average color temperature of 3000 K and are produced with two practically identically located emission segments, but now generated by the reflector segment b _I with a color temperature of eg 3200 K, superimposed.

FIG. 11 shows the superimposition of the emitted beams according to the invention through the reflector 2 in FIG. 11 b in comparison with a beam path of a conventional reflector 49 in FIG. 11 a, in which virtually no superposition takes place as described in FIG.

In this way, the variation of the color temperature in the projection plane can be considerably reduced, in particular by at least 50%.

Between the first and the second zonal layer, in particular, a transition zone can also be inserted which avoids a sharp bend between the two zones 38 and 39. In addition, an adjustment zone can also be provided between the first zonal layer 38 and the neck 9 and / or an adaptation zone between the second zonal layer and the edge of the reflector opening.

The contour of the reflector may be faceted in one or more of the zonal layers, as known per se, to further enhance uniformity.

Finally, the edge of the reflector may preferably be flanged (40) in the vicinity of the opening, so that it directly supports the cover plate 37. On a separate holding mechanism (ring) can be omitted. This is possible in particular when using an aluminum reflector with a small wall thickness.

Claims (9)

Unilaterally capped high-pressure discharge lamp, with a vacuum-sealed inner vessel (2, 3), which is surrounded by a reflector (24), and with a base, wherein the inner vessel sits in a neck portion of the reflector, characterized in that the reflector is constructed rotationally symmetrical and wherein the reflector contour is divided into at least two zonal layers whose axial height is such that each zone captures at least 35% of the light intensity emanating from the center of the inner vessel and wherein a first zone has at least 90% of the light impinging on it the lamp axis is reflected back to positive angles and a second zone reflects at least 90% of the incident light back to negative angles with respect to the lamp axis, and wherein the inner vessel contains a metal halide fill, and wherein the lamp has a given average color temperature. Lamp according to claim 1, characterized in that at least one zone is formed as an open space contour. Lamp according to claim 1, characterized in that also the second zone is shaped as an open-space contour. Lamp according to claim 1, characterized in that the inner vessel is surrounded by an outer bulb in the reflector. A lamp according to claim 1, characterized in that the neck part as a first zone, a flat-walled zone is set, the average inclination is 40 to 70 ° to the lamp axis. A lamp according to claim 1, characterized in that attaches to the first zone, a second steeper wall zone whose average inclination is less than 30 ° to the lamp axis. Lamp according to claim 1, characterized in that the reflector opening is either open or closed by a cover without optical effect. Lamp according to claim 1, characterized in that between the first and second zone of the contour, a transition zone is inserted. Lamp according to claim 1, characterized in that the reflector is made of aluminum, wherein the near-edge region of the reflector directly by means of beading (40) holds a cover plate (37) in the opening.

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