KR200170646Y1 - High-pressure discharge lamp and associated illuminating system - Google Patents

Abstract

The high pressure discharge lamp with an axial axis of symmetry has an asymmetric reflective coating 4 in the cooling spot region of the discharge vessel 2, with the result that the illumination data is improved.

Description

HIGH-PRESSURE DISCHARGE LAMP AND ASSOCIATED ILLUMINATING SYSTEM}

The present invention relates to a high-pressure discharge lamp having an elongated discharge tube (2) cylindrical in the radial direction, including two electrodes (6) defined on the axial symmetry axis and having a discharge volume and located opposite to the axis. It relates to a metal halide lamp with power both ends pinch.

German published application No. 44 43 354 discloses a radially asymmetrically coated high pressure discharge lamp of a bulb. Aperture lamps are referenced in the present invention. This means that by providing a reflective coating on the remaining bulb surface, emission is increased from a narrow bulb area that is not coated. In this case a significant part of the bulb surface is coated.

Axial asymmetric coating of the bulb is described in various ways. For example, German Utility Model No. 94 01 436 discloses metal halide lamps pinched at both ends and axially mounted to the reflector to achieve high luminous flux and high uniformity upon emission. Besides the heat-concentrating spherical cap at the known end, the lamp is also used as an annular radially symmetrical layer that is completely enclosed in the middle of the bulb discharge tube.

It is an object of the present invention to provide a high pressure discharge lamp according to the preamble of claim 1, wherein the wall loading of the discharge tube and the temperature of the cooling spot are increased.

1 is a side view of a metal halogen lamp.

FIG. 2 is a cross-sectional view of the metal halogen lamp of FIG. 1.

3 is a plan view of a pinch showing an embodiment of a metal halogen lamp.

4 is a side view of which the lamp of FIG. 3 is rotated by 90 degrees.

Explanation of symbols on the main parts of the drawings

2: discharge tube 3: discharge tip

4: reflective coating 5: pinch

6: electrode

This object is achieved by the features of claim 1. In particular, the advantages are disclosed in the dependent claims.

High wall loadings increase the proportion of fillers during arc discharge and are desirable because such high wall loadings substantially improve the electrical and lighting data of the lamp.

Up to now attempts have been made to improve the data by changing the composition of the filler and reducing the capacity of the discharge vessel. To date, this has led to high expenditures on improvements resulting from uncertainties. However, setting of the light distribution curve of the lamp is still impossible.

According to the present invention, a radially asymmetric reflective coating is applied to a radially symmetric discharge tube (cylindrical in the radial direction). Such coatings include cooling spots to maintain shading as low as possible and are preferably applied to locally restricted areas with limited sizes between 5% and 40% of the discharge tube surface.

Such spin coatings are made by physical and / or chemical treatment of the discharge tube surface. For example, it is applied to coatings known as metal (aluminum) or nonmetallic materials (particularly zirconium oxides), or layers made by sand spraying or etching. By choosing the geometry of the layers and the coating method, not only the color locus but also the color rendition, color temperature and light distribution curve can be varied and set exactly as desired. This improvement in electrical and lighting data is achieved by specific asymmetric coating of the discharge vessel in the cold spot region. Since heat loss due to the absence of external bulbs is particularly important, significant improvements are achieved with high power (at least 400W to over 1000W) metal halide lamps without external bulbs.

In such lamps the cooling spots are generally located at the back of the electrode. For this reason, both ends of the discharge vessel are often coupled to the heat-concentrating spherical cap. This means that the cooling spot (but at a higher temperature than the spherical cap is unnecessary) is located at the deepest point of the discharge vessel, which is somewhat controlled by the effect of gravity. Importantly, the arc discharge is deflected upwards by the lift. Preferably, a discharge tube composed of an isothermal layer is possible. In this case the size of the cooling area range (temperature gradient) of the cooling spot determines the degree of asymmetric coating. This may be a confined spot or an elongated strip axially. This spot is round, oval or oval.

Under certain circumstances, the system affects the range and location of the cooling area of the cooling spot, so the geometry of the asymmetric coating is determined by the associated light emitting system (e.g. luminaire). The configuration of the light emitting system essential for this purpose is for example a reflector composed of, for example, a through reflector or an elliptical reflector.

The position of the asymmetric coating can be conveniently defined in relation to the discharge tip of the discharge vessel, since the upward direction is the best position while the lamp is operating as a latent heat sink. Therefore, the asymmetric coating is exactly on the opposite side of the discharge tip. Moreover, for practical reasons, no coating is required on the discharge tip area to avoid coating distortion and adhesion problems of the discharge tip.

The lamp is preferably operated in a horizontal mounting position (referred to in the longitudinal axis) and is distinguished by a coating that is at least 30% of the discharge volume length in the axial direction and a coating having at least a center angle of at least 30 ° in the radial direction to the bottom layer of the discharge vessel as the middle of the center angle Are distinguished by. The maximum length of the axial coating is limited by the total length of the discharge vessel, because the shading effect is too large, and by the central angle of up to 180 ° in the radial direction. In this case, a circle or ellipse close to the circle is estimated for the radial direction of the cross section of the discharge tube. In the axial direction, the discharge vessel is thin and long, and preferably has a tubular, cylindrical or oval shape.

The asymmetric coating preferably extends near the end of the discharge volume on which the electrode is seated. In this case, known heat-concentrating spherical caps may additionally be configured at both ends.

Best of all, a suitable lighting system is a wall lighting device with an elongated reflector fitted laterally behind a horizontal lamp. This asymmetric coating prevents significant shading of the radiation emitted by the luminaire.

The coating according to the present invention allows to increase the illumination data of the lamp without significant change of other parameters. It even allows the same reflector paste to be used as is used for end silvering. In addition, since there is no need for additional processing steps, there is no additional cost in production. Force consumption of the reflector paste is negligible.

Due to the elevated operating temperature, which is particularly useful and environmentally friendly, the absolute amount of mercury required to fill the lamp can be reduced by approximately 10-20 mg. In addition, no change to the composition of the filler is necessary for the purpose of improving the lighting data.

In order to ensure a clear and necessary orientation of the lamp in the correct operating position, reference may be made to a base / holder system which is known in orientation, as described, for example, in US Pat. No. 5,731,656. Thus, it is possible to easily ensure the installation position necessary for maintaining the optimum effect and the installation position in the downward direction of the asymmetric coating point.

The present invention is described in more detail below by a number of embodiments.

1 and 2 show a 2000 W high-pressure discharge lamp without an external bulb of approximately 190 mm length, for example described in detail in US Pat. No. 5,142,195. The lamp is arranged in the horizontal and transverse directions instead of the axial direction with respect to the axis of the reflector, but for use in the reflector.

The discharge tube 2 made of silica glass is defined by the longitudinal axis X and the busbar is designed as a cylindrical body in the form of a round arc. The discharge volume is approximately 20 cm ³ . The bar-shaped tungsten electrode rods 6 into which the filaments are inserted are arranged axially on pinches 5 at both ends of the discharge tube. The electrode 6 is fixed on the foil 8 at which the external feed lead 9 starts at the pinch 5. The ceramic base 10 is fixed by cement at the end of the pinch 5 away from the discharge. The discharge tube 2 contains a filler made of an inert gas, mercury (in this case, 180 mg is sufficient instead of approximately 200 mg) as well as a metal halide. At the end of the discharge vessel a heat concentrated spherical cap 13 made of zirconium oxide is provided.

The asymmetric coding 4 is also applied to the discharge tube 2, in particular on the opposite side of the discharge tip 3, which is located at the lowest point in the mounted state and which contains the cooling spot T. Likewise, the asymmetric coating 4 is an elongated elliptical spot composed of zirconium oxide and having an axial width of approximately 50% of the width of the cylindrical body. The maximum radius includes a central angle of approximately α = 55 ° (FIG. 2). Only the front side of the spot is shown in the side view of FIG. 1, and the discharge tip 3 is shown at the top.

Another embodiment is shown in FIGS. 3 and 4. This figure is a 1000W metal halide lamp 19 similar to FIG. 1. 3 is a plan view of the pinch 23. Lamp 19 is shown in FIG. 4. The asymmetric coating 20 spans the entire axial length of the discharge vessel 21 and is connected to the end of the heat concentrating spherical cap 22. The radius corresponds to a central angle of approximately 90 °. The lamp is for mounting to a luminaire with an elliptical reflector 25 mounted horizontally close to the lamp 19. The main direction of forward emission is indicated by arrow 26.

Color locus, color rendition and, in particular, the luminescence flux are considerably improved by asymmetric coating compared to the prior art. In addition, the operating voltage of the lamp is approximately 125V, increasing by an average of 20V. The difference between the coated and uncoated lamps is based on Table 1, where the luminous flux (Ф) (klm), the color coordinates (x, y) and the color rendition index (Ra) are given for both lamps. . There is a significant improvement in luminescence flux (7%) and color rendition index (15%). The color locus is clearly closer to the curve for white (x, y = 0.333) or Planck radiation.

Wipe-resistant reflector paste based on zirconium oxide is used as coating material. The layer thickness and equivalent correspond to the general values of the heat intensive spherical cap. The lamp is coated in the area around the cooling spot formed by the filling condensate during operation. This area is on the opposite side of the discharge tip in special cases.

The present invention has the effect of improving the illumination data of the lamp by providing a radially asymmetric reflective coating on the discharge vessel.

Claims (4)

In the high-pressure discharge lamp having an elongated discharge tube (2) cylindrical in the radial direction, comprising two electrodes (6) defining an axial symmetry axis and having a discharge volume and located opposite the axial direction, In a limited area comprising a cooling spot, the discharge vessel (2) is characterized in that it has a radially asymmetrical reflective coating (4). 2. The high pressure discharge lamp of claim 1, wherein the coating has an axial length of at least 30% of the discharge volume. 2. The high pressure discharge lamp of claim 1, wherein the coating comprises a maximum center angle α of at least 30 degrees in the radial direction. 2. The high pressure discharge lamp as claimed in claim 1, wherein the high pressure discharge lamp is operated in a horizontal mounting position and the cooling spot (T) is located at the lowest point.