EP0926704A1 - Flat signalling lamp with dielectric barrier discharge - Google Patents

Abstract

The flat signal lamp (1) has a discharge envelope which is partially transparent to visible radiation containing a gas filling, with a dielectric layer between the latter and at least one discharge electrode (9a,9k) for providing a dielectrically impeded discharge within the discharge envelope, one boundary surface of which provides the signal output surface. A number of parallel anode and cathode electrodes may be applied to the surface of the discharge envelope facing the signal output surface. An Independent claim for a traffic signal employing a flat signal lamp is also included.

Description

The present invention relates to the field of signal lamps, as they are used primarily with traffic signals and traffic signs Find. In particular, it relates to a traffic light.

In addition to the diverse lighting tasks, the area of Signal lamps for lamp technology. Daily life knows many areas of application for signal lamps: B. road traffic, the Shipping and rail traffic, monitoring and operation of technical equipment of any kind, the security signs of buildings or traffic, commercial or industrial facilities such as airports, Railway stations, cinemas and the like.

There are special requirements for the area of signal lamps characteristic. This includes reliability, operating time and the repair and maintenance effort. This is not only due to safety considerations forth, but also follows from the large numerical and local distribution of signal lamps and the associated considerable Maintenance and repair expenses.

Another important aspect is that with signal lamps depending on the application certain designs or sizes are desired.

Conventional light bulbs or halogen light bulbs become conventional used, especially with such signal lamps that on and in operation must be switched off.

The disadvantages resulting from this are first of all the high sensitivity to vibrations the filament. Especially for applications in the transport sector this results in considerable restrictions. Furthermore have Incandescent lamps depending on the lamp type and the operating voltage used only a relatively limited operating time of a few thousand hours and then, as mentioned above, sometimes have to be replaced with considerable effort become. Ultimately, a short regular operating time is similar disadvantageous as another susceptibility to defects.

Another aspect often arises from special requirements the radiation pattern. Then the light bulbs must be in an optical System are installed, e.g. B. with a mirror reflector and / or with Lenses. First of all there can be misalignments and accordingly Performance restrictions come. In addition, such are optical Systems are complex and generally susceptible to contamination, like they, especially in the transport sector, basically not are to be avoided. The result is regular maintenance elaborate internal cleaning necessary, but it still does not succeed to completely restore the initial properties of the system.

With mirror reflectors, there can also be so-called when the sun is low Phantom lights e.g. B. come in traffic lights. Through reflections the sunlight will illuminate the relevant signal lamp faked.

Another disadvantage that is often necessary in incandescent lamp applications optical systems with reflectors or lenses are necessary Size and design and the corresponding weight. You are in many Cases very undesirable, especially when the lamp is in special positions must be assembled and therefore during assembly and / or with the corresponding brackets, masts or other fastening devices results in a considerable effort. However, leave the necessary Illumination of a larger signaling area or a z. B. emission direction specified by standards no other choice.

A final aspect is the temperature development of incandescent lamps one is large in overall performance and the other is strongly localized. The resulting thermal cycles and thermal gradients form one Stress on the lamp and its technical environment, in particular in non-stationary operating states. The result is a relative one limited switching stability.

A known way to address some of the disadvantages mentioned consists in the use of light emitting diodes (LEDs); they are however often unsuitable because of their radiation characteristics. There is also a disadvantage in that it is important in many signal lamp applications and also frequently standardized color location is not adjustable or when in use of phosphors is not permanently adjustable due to stability problems.

This invention is based on the technical problem of a new signal lamp indicate the ways to avoid the mentioned Offers difficulties.

According to the invention, this problem is solved by a gas discharge lamp with one that is at least partially transparent to visible radiation and with a gas filling discharge vessel and with a dielectric Layer between at least one discharge electrode and the gas filling for a dielectric barrier discharge in the discharge vessel, characterized in that the lamp is a signal lamp with a signal surface and the discharge vessel is a continuous boundary surface has, which corresponds to the signal area.

The invention is based on the knowledge that many conventional Reservations against the use of gas discharge lamps in the area the signal lamp technology can either be overcome technically or the associated disadvantages in favor of other benefits in buying can be taken. First, speaks against the use of Gas discharge lamps compared to incandescent or halogen incandescent lamps Need to use elaborate starting circuits or electronic Ballasts. On the other hand, especially in the field of electronic Ballasts make significant progress in reducing the Price and size have been achieved, and also in the field of conventional Halogen light bulbs are transformed by transformers using low-voltage technology accepted similar disadvantages.

Another point is the reduced switching stability due to the starting process of gas discharge lamps. Here it turned out that through Gas discharge lamps with dielectric barrier discharge switching strengths that the conventional incandescent lamps achieve by far exceed and essentially only by the stability of the used Phosphors or phosphor mixtures are determined. By the opposite the insensitive electrode shape and the smaller ones Thermal cycles during operation can now be an advantage of switching stability Gas discharge lamps with dielectric barrier discharge opposite conventional light bulbs. Here too, one of prejudice stemming from conventional gas discharge lamp technology not proven to be well-founded in this special case.

Another point that initially opposed the use of discharge lamps speaks depends on the consistent use of mercury in the corresponding gas fillings together. Mercury doesn't just have adverse effects Environmental aspects but also ensures adverse temperature properties the lamp. This affects the instant light properties first, So the (lacking) possibility of immediately after switching on the deliver full light output. In addition, this problem is also from the Depending on outside temperatures, i.e. particularly pronounced in cold environments. However, it has now been found that when using a Dielectric-barrier discharge lamp not containing mercury Gas fillings are more necessary, making these problems complete omitted.

A major advantage of this invention is that of the individual Requirements very flexible in shape and size, especially adaptable geometry of flat lamp discharge lamps. Discharge lamps stand out through a largely homogeneous distribution of light generation over the discharge volume, so that additional optical components can often be omitted. So the z. B. at traffic lights the annoying Specular reflectors and phantom light for reducing of the phantom light additional screens are not necessary. Rather, it can be done only with regard to the flat lamp discharge lamp the phantom light effect achieved a much better result than when using these components in the conventional case, whereby there is an important contribution to road safety.

The mirror reflectors have led to the possibility of directional distribution adjust the light emission very well and choose can. To this extent, there have been concerns regarding gas discharge lamps, in particular if there are no additional specular reflectors, one too undirected Radiation z. B. to get into the half space that really in the decisive directions did not produce sufficient luminance. How is explained further below, however, there are possibilities according to the invention found the luminance distribution even in the case of flat radiators Focus gas discharge lamps if this is in a particular Use case is necessary.

With the omission of mirror reflectors, panels and other separate optical Components are also omitted, especially in the state of the Technological requirements for the external shape of the signal lamp or - light, e.g. B. with regard to a certain minimum thickness, at least preferred use of a round outer shape, etc. The same applies for saving weight.

Accordingly, the problems described at the beginning also disappear the internal pollution of signal lamps, e.g. B. traffic lights. There by appropriate choice of the phosphor or the phosphor mixture very many color words can be hit, you can save the conventional necessary filter discs. You don't just win in the Luminous efficacy, rather the area of interior cleaning is completely eliminated. At correspondingly dense or encapsulated version of the invention Signal lamp can do the occasional external cleaning in particular be carried out easily, e.g. B. with one even from a greater distance usable water jet.

In connection with saving the conventionally required Reflectors, filter discs, etc. also include the advantage of the invention that the elaborate and by the adjustment due to the thermal cycles adjustment required during operation or at least when changing the light bulb the position of the light bulb or its base is also eliminated.

Fluorescent lamps are also generally less sensitive to Vibrations as incandescent lamps and are therefore very suitable better for various mechanical shocks or vibrations exposed locations of signal lamps, especially in the traffic sector.

This invention is primarily intended for flat radiator discharge vessels, in which a continuous flat shape of the discharge volume directly at least essentially specifies the shape of the flat radiator. In contrast, e.g. B. conventional tube discharge tubes, the For example, backlighting a flat lens, none continuously flat discharge vessels if they are used to fill the backlight Surface are coiled accordingly or in serpentines. Of course, the flat radiator can still have wavy surfaces or to be curved in its flatness.

The signal area mentioned in claim 1 is that for exercising the signal function the area used for the signal lamp. It can have a signal color Have lettering, carry hazard symbols etc. This signal area does not have to with the assigned boundary surface of the discharge vessel be identical and can be, for example, by means of different optical intermediate layers be separate from it. In any case, the signal area is at least essentially back-lit through the boundary surface or illuminates and corresponds to it at least in this sense. Prefers are the signal area and the corresponding boundary area also geometrically congruent.

In a preferred embodiment of the invention, the electrodes are the flat-beam discharge vessel arranged on one of its surfaces, in particular so that they run side by side. Through this there is a common arrangement on one surface of the discharge vessel the possibility of a particularly simple production because only one surface must be coated with electrode structures. In addition, this means that discharge structures fill the surface particularly evenly produce. This is from the description of what follows below Embodiment clearly.

In this preferred form of discharge electrodes can continue the discharge anodes and the discharge cathodes from a plurality parallel discharge anodes and cathodes each together connected on a common side (the anodes or the cathodes) and be connected to a single anode or cathode connection. In particular, as shown in the exemplary embodiment, there is a straight line Shape of the discharge anodes and cathodes with opposite ones Sides to a comb-like arrangement of the discharge anodes and cathodes extending common connections.

In favor of improved control and thus greater uniformity the arrangement of the individual discharges or discharge structure in the discharge volume, projections can be made on the electrodes for local Definition of a single discharge element, that is, a single one from the plurality of discharges. This is also on referred to the embodiment.

With the dielectric barrier discharge, at least the anode side must be covered with a dielectric layer. Which also in the main claim listed dielectric layer can, however, also through a wall of the Discharge vessel can be formed when at least part of the electrodes is applied on the outside of this wall.

In many cases, especially if the light is only emitted to one side is to use a reflection layer on a discharge vessel wall provided, in contrast to the specular reflector diffuse reflection of light from the lamp. Usually included Gas discharge lamps on the walls of the discharge vessel layers of fluorescent material, the reflection layer then facing away from the discharge Side of the phosphor layer. The use of a However, phosphor is not mandatory for this invention. Should be dielectric disabled discharges are possible where the desired Light is generated directly in the discharge, so is this invention Executable without fluorescent.

The radiation behavior of the gas discharge flat radiators is fundamental relatively diffuse, d. H. in all directions from the plane of the flat radiator directed. This also applies to the optional use of a diffuse reflective layer. A further configuration is required for some applications to be preferred to the invention, in which the substantially (with one-sided Reflection layer) the solid angle area covering the half space the light radiation is restricted to a narrower solid angle range. According to the invention, luminance reinforcement layers, in particular Fresnel lenses or prism foils or prism plates as simple flat optical elements used on the flat radiator. Especially can be so-called brightness enhancement foils as prism foils (Brightness Enhancer) can be used that the cone of light emission in one dimension, or when using two in their longitudinal direction of the prism right-angled brightness enhancement films in two dimensions, narrow. Such brightness enhancement films are described below in Embodiment described in more detail. The luminance enhancement layers can also be prism-free, for example with a refractive index variation, be constructed.

A diffusely scattering film or plate can also be used, with the simultaneous use of a prismatic film on the lamp side from that. Such a diffuser is particularly advantageous if one Larger area of the discharge vessel through support points, that is, across the plane of the flat radiator Small columns between the discharge volume enclosing plates, is stabilized. Through the diffuser these support points are less visible.

As a preferred discharge system for those largely in terms of their Discharge lamp described geometric and electrotechnical construction the Xe Excimer system can be used. This is preferred used with a pulsed discharge operation. For the details of Xe excimer discharge lamps and the pulsed discharge operation referred to the applications WO 94/23442 and DE-P 43 11 197.1 and WO 97/04625 and DE 195 26 211.5, the disclosure of which is referred to here and is included.

This invention relates generally to signal lamps of all types. Various areas of application have already been described in the introduction. However, it is particularly useful in the transport sector and both in road traffic, rail traffic, shipping as well Air traffic. A particular aspect of the invention relates accordingly on a traffic sign or a traffic signal that an inventive Signal lamp contains or consists of it. Many of the above Advantages of the invention, such as the lower susceptibility to pollution, the Phantom light problem, the longer operating time, especially when exposed to vibration Locations, the improved switching stability, etc. play in the area of traffic signs and traffic signals play a particularly large role.

It is particularly important to think of a traffic light, two of which or three differently colored signal lamps, each one according to the invention Fluorescent flat spotlights are. The exemplary embodiment also relates to this. It is also important to use it as a motor vehicle lamp, e.g. B. Brake light, or direction indicator, which is also built around a vehicle corner and can be designed curved. In all of these cases, like Generally with signal lamps, it is particularly advantageous to use the frequently standardized Color, more precisely the color locus, already through the right phosphor or To be able to set fluorescent mixture selection. There are no only particularly good technical possibilities for the exact setting of the Color locations, but the conventional color filter technology is often unnecessary.

Figur 1 eine geschnittene Draufsicht auf die Signallampe für eine Verkehrsampel,

Figur 2 eine geschnittene Seitenansicht durch die Signallampe,

Figur 3 eine Draufsicht auf eine Bodenplatte der Signallampe, wobei die Elektrodenstruktur dargestellt ist,

Figur 4 eine schematische Darstellung von drei zu einer Verkehrsampel zusammengesetzten Signallampen nach den Figuren 1 bis 3.

The following is a description of the preferred exemplary embodiment, namely a signal lamp for a traffic light. This embodiment is shown in the figures, which shows:

FIG. 1 shows a sectional top view of the signal lamp for a traffic light,

FIG. 2 shows a sectional side view through the signal lamp,

FIG. 3 shows a plan view of a base plate of the signal lamp, the electrode structure being shown,

FIG. 4 shows a schematic illustration of three signal lamps according to FIGS. 1 to 3 assembled to form a traffic light.

In Figure 1, a round signal lamp 1 is drawn for a traffic light. The sectional view shows the discharge volume within the smallest Circle 2. Here are cuts through in a square grid of 34 Support points 3 arranged along the edge length are drawn as small round dots. The area between the smallest circle 2 and the middle one Circle 4 contrasts the lateral sealing of the discharge volume represents the outside world. The outer circle 5 is the outer edge of the discharge volume limit upwards and downwards (in the perspective of the figure) Glass panes 6 and 7. These glass panes are shown in FIG Section shown. In this embodiment, the diameters are of the three circles 2.4 and 5 200, 220 and 240 mm.

Signallampe und Leuchtstoffe dazu".Figure 2 shows a section in a direction perpendicular to Figure 1. An Xe discharge fill is enclosed between the two glass plates 6 and 7. Typical thicknesses for the glass plates are 2.5 mm and for the gas filling 8 about 5 mm. Ag electrodes 9 are first drawn in cross section on the lower glass plate 7, the geometry of which is described in more detail with reference to FIG. 3. A glass solder layer 10, which forms the dielectric of the dielectric barrier discharge, is located on the electrodes 9. This is followed by a reflector layer 11 made of Al ₂ O ₃ or TiO ₂ for the diffuse reflection of the light generated in the lamp 1. A phosphor layer 12 for generating light is located above the reflector layer 11. The same phosphor layer 12 is also located on the lower side of the glass plate 6 shown in the illustration. These phosphor layers are optimized for the respective application, in particular the desired color location. For the present example of a traffic light, preferred luminescent materials or luminescent material combinations are contained in the application of the same applicant from the same day with the title, in terms of its disclosure content:

Signal lamp and fluorescent lights ".

In some applications, e.g. B. at the red signal lamp of the traffic light, it may make sense to provide a color filter 13 on the glass plate 6, compare the application just cited.

A diffuser is located above the glass plate 6 and the optical color filter 13 14, that generated by the phosphor layers 12 and by the reflector layer 11 reflects light so diffusely that the one shown in FIG Support points in the luminous appearance of the signal lamp only are weakly recognizable.

The electrodes and layers 9-12 applied to the glass plates 6 and 7 can be produced particularly easily using the screen printing process.

The screen printing process is u. a. advantageous for structuring the electrodes. For the sake of simplicity, it is also used for the other layers.

On the optional color filter 13 and the diffuser 14 there are in turn two luminance intensifying foils 15 and 16 crossed with their longitudinal prism axes. Such luminance intensifying foils are prism foils which, through refraction of the light on the prism surfaces, cause the radiation cone of the light to narrow in the plane perpendicular to the prism longitudinal axis. An example of this are those commercially available from the manufacturer 3M Brightness Enhancement "films. Depending on the application, the angle of attack of the prisms can be optimized in order to align the emitted light to the required extent.

In this embodiment, the signal area is the luminous area on the upper luminance enhancement film 16. The signal function is reduced the red, yellow or green signal lamp 1. On the other hand, the signal area is corresponding in the sense of claim 1 Boundary surface of the discharge vessel, the upper glass plate 6. From the Interposition of the different optical layers apart, correspond these areas and are congruent.

FIG. 3 shows a top view comparable to FIG. 1, but only the geometry of the electrodes 9, which cannot be seen in FIG. 1, on the lower one Glass plate 7 is located. You can see a toothed basic geometry, which resembles two straight combs pushed together. At this comb-like geometry are those shown on the left in the figure Anodes 9a in pairs, while those shown on the right Cathodes 9k each lie individually between adjacent pairs of anodes. The cathodes 9k regularly alternate on both sides along their length arranged small projections 17 on the spatial fixing each serve a single discharge structure. About this electrode structure reference is made to the application DE 196 36 965.7, the disclosure of which is included here. The next distance between two distances is in this embodiment 5 mm or between equilateral Projections 10 mm.

The area of limitation of the anode and cathode crests 9a or 9k corresponds to the inner circle 2 already mentioned in FIG. 1 Electrodes are on the left and right sides of the figure, respectively merged into a common anode or cathode connection, that on the outer periphery of the in Figure 1 as the outer edge of the glass plates introduced outer circle 5 is. These each circle segments over the Longitudinal extension of the inner circle 2 representing common connections are, in Figure 3 below, to an anode connection or to a cathode connection led out.

Figure 4 finally illustrates in a schematic view how three the previously described signal lamps 1 are combined to form a traffic light are. Because of the special design of each Signal lamps 1 a very flat housing 18 are used, the rest has the usual high rectangular shape. The conventional ones Traffic lights with light bulbs used elements such as diffusers, Umbrellas and parabolic mirrors can be omitted. Nevertheless the advantages of the invention already described are achieved, in particular the phantom light effect no longer occurs because there is no specular reflector is present that could reflect the obliquely arriving sunlight. Such a traffic light 19 could be of a very simple and easy design Stand are attached, but also by the low weight can be easily hung on ropes and offers due to overall the significant simplifications in weight and volume and the large Freedom for the housing 18 multiple uses.

In the case of motor vehicle signal lamps, freedom in the choice of shape is in the Of great importance in terms of body design. In the simplest The signal lamp shown in FIGS. 1-3 can also be seen as a circular case red taillight or circular yellow direction indicator one Introduce car. The lamp can also be curved around a corner of the vehicle be. This can be particularly the case with rear, brake light or direction indicator lamps be advantageous, which is also from the side of the vehicle can be recognized by other road users. Since the invention the construction of particularly flat motor vehicle lamps enables is such a tour around a motor vehicle corner without this conventionally predetermined considerable depth in the body possible inside.

Claims (15)

Gas discharge lamp (1) with a discharge vessel which is at least partially transparent to visible radiation and filled with a gas filling (8) and with a dielectric layer (10) between at least one discharge electrode (9) and the gas filling for a dielectric barrier discharge in the discharge vessel,
characterized in that the lamp (1) is a signal lamp with a signal surface and the discharge vessel has a continuous boundary surface (6) which corresponds to the signal surface. Signal lamp (1) according to Claim 1, in which the discharge electrodes (9) on a surface (7) of the discharge vessel opposite the signal surface are arranged. Signal lamp (1) according to claim 1 or 2, wherein a plurality in parallel extending discharge anodes (9a) or cathodes (9k) each on one common side of the anodes (9a) or cathodes (9k) together connected and on a single anode or a single Cathode connection are connected. Signal lamp (1) according to one of the preceding claims, in which at least one of the discharge electrodes (9) has a structure of protrusions (17) for local determination of the individual discharge elements of the has dielectric barrier discharge. Signal lamp (1) according to one of the preceding claims, in which at least part of the electrodes (9) of the discharge vessel on the outside is applied to a wall and the dielectric layer is formed by the wall. Signal lamp (1) according to one of the preceding claims with a reflection layer (11) on a wall of the discharge vessel for diffuse Reflection of the light from the signal lamp (1). Signal lamp (1) according to one of the preceding claims with a on the boundary surface (6) corresponding to the signal surface Discharge vessel arranged diffuser (14). Signal lamp (1) according to claim 7 with one on the of the signal surface corresponding boundary surface (6) of the discharge vessel and the diffuser (14) arranged luminance enhancement layer, for example a prism sheet (15, 16), prism plate or Fresnel lens. Signal lamp (1) according to claim 8 with two in their prism longitudinal direction perpendicularly crossed brightness enhancement foils (15, 16) as Prism foils. Signal lamp (1) according to one of the preceding claims, designed for a Xe excimer discharge. Signal lamp (1) operated according to one of the preceding claims through pulsed energy coupling. Traffic sign or signal with a signal lamp (1) according to one of the preceding claims. Traffic signal according to claim 12 as traffic light (19). Traffic signal according to claim 12 as a motor vehicle lamp. Motor vehicle lamp according to claim 14 as extending around a vehicle corner, curved tail, brake light or direction indicator lamp.

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