WO2008142617A2

WO2008142617A2 - High-pressure discharge lamp

Info

Publication number: WO2008142617A2
Application number: PCT/IB2008/051913
Authority: WO
Inventors: Sven Schellinger; Albrecht Kraus; Lukas KÜPPER
Original assignee: Philips Intellectual Property & Standards Gmbh; Koninklijke Philips Electronics N. V.
Priority date: 2007-05-23
Filing date: 2008-05-15
Publication date: 2008-11-27

Abstract

The present invention relates to a high-pressure discharge lamp having at least one burner comprising a discharge chamber, having two electrodes extending into the discharge chamber, having a gas filling in the discharge chamber containing at least one inert gas and one metal halide mixture, and having a light-absorbing coating that is disposed on at least part of the exterior piston and/or of the discharge chamber.

Description

HIGH PRESSURE DISCHARGE LAMP

The present invention relates to a high-pressure discharge lamp comprising at least one burner having a discharge chamber with two electrodes extending into the discharge chamber, with a gas filling in the discharge chamber containing at least one inert gas and a metal halide mixture, and with a light-absorbing coating, which is arranged at least on a part of the outer bulb and / or the discharge chamber.

High-intensity discharge (HID) lamps and, in particular, xenon HID lamps, due to their optical properties and the like, may be used. a. preferably used as a light source for headlights for vehicles, especially headlights.

For the purposes of the invention, the term xenon HID lamp (Philips) also includes xenon HID-type lamps from other manufacturers. For these applications, an optical light source is required, with the difference between the electrode tips, i. H. the free distance between the two electrodes, forming arc in a regulation has defined and specified dimensions in terms of arc length, arc curvature and arc diffusivity.

Lamps that are to be used for vehicle headlamps are subject to international standards, such as the SAE or ECE standards, which concern the European or US market in particular, with regard to their most important parameters.

Headlights for vehicles, for example with low beam function, are within the meaning of the invention, all headlights that produce a cut-off, such as for example, pure dipped beam headlights or combined high and low beam headlights.

Usually headlamps are equipped with lamps that radiate visible light in almost all directions with almost the same color, so that then regularly a color homogeneously illuminated traffic space is effected.

Although it is known that bluish light is better reflected on obstacles in the traffic area, for example traffic signs, and thus can be perceived better or earlier, in particular for the driver of the vehicle, which illuminates the traffic space in this regard, but on the other hand in particular the oncoming traffic in an undesirable manner displayed.

At present, high-pressure gas discharge lamps are used in reflection systems of vehicle headlights, in particular for dipped headlights. Such lamps are u. a. commercially available as DIR, D2R, D3R and D4R lamps.

To avoid a significant glare of the oncoming traffic by scattered light, which by a refraction of salt deposit (so-called

"Salt Lake") of this type of lamp is caused, strip-shaped light-absorbing coating (so-called "Pinstripes") are arranged along the lamp longitudinal axis in a well-defined manner and on the outer surface of the lamp envelope. The defined manner of dimensioning and arranging such a strip-like light-absorbing coating ("pinstripes") was disclosed inter alia by DE 695 01 653 T2 This coating according to the teaching of DE 695 01 653 T2 consists of several parts, ie one This first partial ring segment is arranged in the area near the base with respect to the center of the distance between the two electrodes, extending on the longitudinal axis of the piston The first partial ring segment is penetrated at its two ends which are parallel and coaxial to the lamp longitudinal axis delimited two strip-shaped partial ring segments, which extend to the pedestal-free end of the lamp envelope These two strip-shaped partial ring segments each have their greatest extent parallel to the lamp's longitudinal axis; their smaller extent coaxial on a surface perpendicular to the lamp longitudinal axis.

The first partial ring segment is arranged in a zone which is in the vicinity of the first socket-like neck-shaped part of the outer bulb. This partial ring segment does not form a completely closed ring and thus has an annular gap which has a slot-shaped opening parallel to the lamp longitudinal axis.

The return conductor of the lamp, which extends outside of the lamp envelope, is arranged with respect to its longitudinal axis parallel to the longitudinal axis of the burner, which usually also corresponds to the lamp longitudinal axis. The opening of the annular gap is spatially, in particular symmetrically, arranged between these two longitudinal axes.

The arrangement of the two outer edges of the first partial ring segment, each lying in one of two planes, which are arranged parallel to a plane which extends perpendicular to the longitudinal axis of the burner through the center of the free path between the electrodes, is defined by the angle A and B determines.

The plane which, standing vertically on the longitudinal axis of the burner, passes through the center of the free path between the electrodes, forms in each case one limb, namely the first limb of the angle A and of the angle B. The second limb of the angle A is tangent the socket-remote outer edge of the first partial ring segment; the second leg of the angle B is tangent to the near-bottom outer edge of the first partial ring segment. The vertices of the two angles A and B lie on the longitudinal axis of the burner.

The angle A is about 45 °, but may have a tolerance of ± 5 °; The angle B is about 65 °, but can also be chosen slightly larger.

For the dimensioning and arrangement of the two, subsequent to the first partial ring segment, strip-shaped partial ring segments takes place according to the angle C and D. Here, the angle C is the angle which results between the two legs, which have their point of intersection in the longitudinal axis of the burner and each tangent to the opposite edges (12 \ 13 ") tangent.The angle C is preferably about 165 °. The angle D is the angle which results between the two legs, which have their point of intersection in the longitudinal axis of the burner and each tangent to the mutually facing edges (12 ", 13"). The angle D is preferably about 85 to 145 °. The angle C is the angle of the asymmetrical light beam for left or right traffic. The freedom of choice for the angle D gives an allowable maximum width, which according to the teaching of DE 695 01 653 T2 for thermal reasons should not be exceeded.

By previously equipped with Pinstripes lamps or Reflektionssy systems adheres to the disadvantage that, in an approximately horizontal mounting position of the lamp, light is emitted both upwards and downwards. The downwardly radiated light is thereby additionally broken at least partially by the deposits of salt usually present in this lamp type on the inner bottom wall of the discharge chamber (so-called salt lake). The resulting undirected, in particular yellow, stray light is undesirable, since a part of it enters the area of oncoming traffic and can lead to glare there. In addition, the contrast of the cut-off line is reduced by this stray light.

The solution shown is also limited solely to an approximately horizontal mounting position of the lamp; other mounting positions, which would allow a wider application, are not possible.

The object of the invention is to provide a high-pressure gas discharge lamp which, based on the total amount of emitted light, emits a lower proportion of scattered light into the traffic space and allows a greater contrast of the cut-off line, thereby causing an increase in the efficiency of the lamp. In addition, different mounting positions of the lamp should always be possible.

The object of the invention is solved by the features of claim 1.

It is essential to the invention that with the at least partially light-absorbing, at least partial coating, in the burning position of the lamp, starting from the middle of the connecting line of the two electrode tips with the Gravity vector is a rotary cone with a Öffhungswinkel of at least 5 degrees on the discharge chamber and / or an outer bulb can be covered.

The term rotary cone is to illustrate in the sense of the invention that the part of the surface of the partial coating, which prevents the stray light coming from the salt lake does not reach the reflector, at least one such surface containing within the outer contour of a rotary cone with an opening angle of at least 5 degrees.

Regardless, the outer contour of the partial coating may have other shapes, such as those of an ellipse, rectangles, or an irregular geometric figure.

For the purposes of the invention, the partial coating need not only be a closed surface, but may also consist of several surfaces which do not touch and / or partially touch their contours.

For example, the partial coating according to the invention may comprise two pin strips according to the teaching of DE 695 01 653 T2 and also a part which, with the acceleration due to gravity, covers a rotary cone with an opening angle of at least 5 degrees on the discharge chamber and / or an outer bulb.

In no case does the outer contour of the coating according to the invention exceed the outer contour of the two pin strips according to the teaching of DE 695 01 653 T2 or the area of the outer contour which would occupy them.

With this surprisingly simple solution, in particular with a horizontal installation position of the lamp in a conventional reflection system, no visible light or only defined portions of the visible light is emitted downwards. In the case where no visible light is radiated down, no unwanted stray light is caused thereby. The contrast of the cut-off line is thus increased by the absence of scattered light. Blinding of other road users by such undirected, in particular yellow scattered light is avoided. This is a respect to the color impression of the headlight coming light as brilliant, especially blue or white, appearing perceived.

In the case where defined portions of visible light are emitted downwards, desired stray light is generated. This desired scattered light makes it possible to influence the characteristic of the light emitted by this reflection system into the traffic space in a defined manner. This can be achieved in a customary manner by the selection and dimensioning of the type of coating or its properties, for example as a filter, for the respective application.

Also, the portion of the yellow light is preferably absorbed by the deposited salt, so that a total of a whiter light enters the traffic area.

Furthermore, the shielding of the (yellow) scattered light through the salt lake makes the color impression of the spotlight much more brilliant (blue or white).

It has been determined by experiments that with a turning cone with an opening angle of at least 5 degrees, the desired object is achieved within the scope of an industrial mass production with sufficient efficiency and accuracy. At an opening angle of less than 5 degrees this is not the case.

Due to the increased convection, in horizontal installation position, the lower part of the lamp bulb becomes hotter, thus also increasing the efficiency. That is, the lamp performance is improved, with more lumens per watt achievable, or with equal efficiency, the amount of salt in the combustion chamber can be reduced.

With installation positions other than horizontal, for example, installation position by 45 degrees from the horizontal, the effects of using the g vector come particularly clearly to bear. By this reference to the g-vector (the direction of the vector of gravitational force, which always points in the direction of the center of the earth), the solution according to the invention from the horizontal in a simple manner to other mounting positions transferable and practicable.

The deposited salt always gets to the bottom of the combustion chamber - regardless of the installation position of the lamp - due to gravity and convection the coldest spot in the lamp.

Advantageous embodiments indicate the subclaims; without limiting the invention.

It is preferable for the coating to allow portions of blue light to pass better than other portions of the visible light.

It is preferred that the coating allows portions of infrared light to pass better than other portions of the visible light.

In addition, it is preferred that the light-absorbing coating also consist of at least a first part and two second parts, and this is arranged on a part of the surface of the outer bulb, wherein the first part of the coating is a ring or a segment of a ring which is arranged close to the socket is, wherein this first part extends at least from a location which forms an angle A of about 45 ° with the perpendicular to the outer bulb at the intersection with the middle of the distance between the electrodes, at least up to a location which is at an angle with this perpendicular B is about 65 °, with the vertices of A and B lie on the longitudinal axis of the burner, the second Teil_der coating has a strip shape and lies with its socket near the end portion without a gap, the two second parts which are parallel to the longitudinal axis of the Burner run and have opposite side edges, which has an angle C of nearly 195 °, and have side edges facing each other which enclose an angle D of about 115 °, the vertices of C and D lying on the longitudinal axis of the burner, with a third part with its socket-like end resting against the first part without a gap and the two side edges abut gap-free at the side edges.

Further details, features and advantages of the invention will become apparent from the following description of two preferred embodiments with reference to the drawing. Show it:

1 shows a high-pressure discharge lamp according to the invention with a burner and an outer bulb in a side view (first embodiment), 2 shows a cross section along the center of the burner in Fig. 1, with contours of the lamp cap,

3 shows a high-pressure discharge lamp according to the invention with a burner and an outer bulb in a side view (2nd embodiment), and FIG. 4 shows a cross-section along the center of the burner in FIG

Outlines of the lamp cap (2nd embodiment).

In Fig. 1, a capped high-pressure discharge lamp (1st embodiment) with a burner 1 and an outer bulb 10 is shown in side view.

The lamp is shown in an approximately horizontal installation position, wherein the salt deposits 16 are in the discharge chamber 2, there on the inner surface of the discharge chamber 2 and its lower region. The lamp has a vacuum-sealed, translucent

Burner 1, which consists of quartz glass. The burner 1 encloses a

Discharge chamber 2. The discharge chamber 2 is equipped with an ionizing gas mixture which contains at least one inert gas, in particular xenon, and a metal halide

Mixture includes, filled. In the discharge chamber 2, the electrodes 3 and 4 are arranged opposite to each other in a conventional manner. The free distance between the two electrodes 3 and 4 is the discharge path; in the middle also the

Center of the discharge chamber 2 is located.

The burner 2 has an axis 5, which is also the lamp longitudinal axis on. The outer bulb 10 is fixed to the burner 2 in the region of the two seals, not shown in Fig. 1. In the discharge chamber 2 are also the electrodes

3 and 4 are arranged with corresponding electrical contacts, which are each secured in one of the two seals. The two electrodes 3 and 4 are on the

Lamp longitudinal axis arranged.

The electrode 3 is in a conventional manner with the current conductor 14, which is electrically conductively connected to the first contact, and the electrode 4 with connected to the second current conductor 15. The second current conductor 15 is also connected to the return pole 7, which is guided approximately parallel to the lamp longitudinal axis outside the outer bulb 10 to the base 6 and is connected to the second contact. The first seal is at the bottom end of the tubular

Outer piston 10 attached.

On the surface of the outside of the outer bulb 10, see also Fig. 2, a light-absorbing coating 8 is arranged. This multi-part coating 8 is a partial coating, i. H. this is not applied to the entire surface of the outside of the outer bulb 10. The first part 11 of this coating 8 extends annularly over a part of the circumference of the outer side of the outer bulb 10 and partially shadows the part of the seal adjoining the discharge chamber 2.

The width of the ring (first part 11) is equal to the dimension between the two intersections of the two legs of the angles a and b, which are not perpendicular to the lamp longitudinal axis, with the cylindrical outer side of the outer bulb 10. The distance of the annular first part 11 of a plane perpendicular to the longitudinal axis and passing through the center of the free distance between the electrodes 3 and 4 imaginary surface, which also forms the other leg of the angle a and b, resulting from the angle a. The respective vertex of the angles a and b lies at the intersection of this imaginary surface with the axis 5.

In Fig. 2 is shown in cross-section, along the center of the burner, in Fig. 1, the lamp of FIG. 1 with contours of the lamp cap.

The coating 8 is at least light-absorbing and consists of at least a first part 11 and two second parts 12, 13. The first part 11 of

Coating 8 is a ring or a segment of a ring and arranged close to the base. In this case, this first part 11 extends at least from the place that forms an angle A of about 45 ° with the perpendicular to the outer bulb 10 at the intersection with the center of the free distance between the electrodes 3, 4, to at least the place with this perpendicular forms an angle B of about 65 °. The two vertices of A and B lie on the longitudinal axis of the burner 1 and the axis of the fifth

The two second part 12, 13 of the coating 8 have a strip shape and lie in each case with its socket near end on the first part 11 without gaps.

The two second parts 12, 13, which run approximately parallel to the longitudinal axis of the burner 1, each have two side edges, namely in each case a mutually applied side edge 12 \ 13 "and a side edge 12", 13 "facing each other. 13 "enclose an angle C of nearly 195 °. The mutually facing side edges 12 ", 13" enclose an angle D of about 115 °, wherein the vertices of C and D lie on the longitudinal axis 5 of the burner 1.

The third part 9 of the coating 8 is partly light-absorbing and also allows portions of blue light to pass better than other portions of the visible light.

The third part 9 rests with its socket near end on the first part 11 gap-free. The two side edges of the part 9 abut against the side edges 12 ", 13" of the two second parts 12, 13 without gaps.

The third part 9 of the coating 8 is a filter consisting of a material which transmits blue or infrared light and reflects or absorbs the remaining portion of the spectrum, or reflects or absorbs the entire spectrum. The filter has the following filter parameters: It reflects or absorbs predominantly in the wavelength range from 420 to 830 nm, and transmits wavelengths below or above this range. The degree of transmittance of the filter with respect to wavelengths below 420 nm or above 830 nm is> 5% in each case.

The lamp has a common base 6 so that it can be arranged as a replaceable lamp in a front headlight of an automobile. A lighting system for automobiles with such a high-pressure discharge lamp according to the invention makes it possible to achieve a light quantity of approximately 85 Im / Watt. The life of a high-pressure discharge lamp according to the invention is at least 1000 hours. The outer bulb 10 has, see also Fig. 2, a light-absorbing

Coating 8, wherein the third part 9 of the coating 8 is arranged approximately symmetrically to the return pole 7 and close to this.

The partially light-absorbing, at least partial coating 8, at least consisting of the parts 9, 12 and 13, covers in the installation or burning position of the lamp from the middle of the connecting line of the two electrode tips starting with the acceleration due to gravity a rotary cone with an opening angle of at least 5 , preferably at least 10 degrees on the discharge chamber 2 and / or an outer bulb 10 covers.

As an alternative to this first embodiment according to FIGS. 1 and 2, it is within the meaning of the invention that the two parts 12, 13 and the third part 9 form a closed surface which has an identical or deviating layer structure. This surface, consisting of the two parts 12, 13 and the third part 9, can also act completely or partially light-absorbing and have an identical or deviating material structure. In Fig. 3 is a capped high-pressure discharge lamp (2.

Embodiment) with a burner 1 and an outer bulb 10 is shown in side view.

The lamp is shown in an approximately horizontal mounting position, wherein the salt deposits 16 are in the discharge space 2, there on the inner surface of the discharge space 2 and its lower region.

The lamp has a vacuum-tight, transparent burner 1, which consists of quartz glass. The burner 1 encloses a discharge chamber 2. The discharge chamber 2 is filled with an ionizing gas mixture which comprises at least one inert gas, in particular xenon, and a metal halide mixture. In the discharge chamber 2 are the Electrodes 3 and 4 arranged opposite each other in a conventional manner. The free distance between the two electrodes 3 and 4 is the discharge path.

The burner 2 has an axis 5, which is also the lamp longitudinal axis on. The outer bulb 10 is attached to the burner 2 in the region of the two seals, not shown in FIG. In the discharge chamber 2, the electrodes 3 and 4 are also arranged with corresponding electrical contacts, which are each secured in one of the two seals. The two electrodes 3 and 4 are arranged on the lamp longitudinal axis.

The electrode 3 is connected in a conventional manner to the current conductor 14, which is electrically conductively connected to the first contact, and the electrode 4 to the second current conductor 15. The second current conductor 15 is also connected to the return pole 7, which is guided approximately parallel to the lamp longitudinal axis outside the outer bulb 10 to the base 6 and is connected to the second contact. The first seal is attached to the socket near end of the tubular outer piston 10.

On the surface of the outside of the outer bulb 10, see also Fig. 4, a light-absorbing coating 8 is arranged. This multi-part coating 8 is a partial coating, i. H. this is not applied to the entire surface of the outside of the outer bulb 10. The first part 11 of this coating 8 extends annularly over the entire circumference of the outer side of the outer bulb 10 and partially shadows the part of the seal adjoining the discharge chamber 2. The first part 11, the two second parts 12, 13 of this coating 8 correspond to the parts 11, 12 and 13 shown in FIG. 1 (1st embodiment).

On the surface of the outside of the outer bulb 10, see also Fig. 4, a light-absorbing part coating 9 is arranged. The outer contour of the part 9 of the coating 8 corresponds to the line that arises when the conical surface of a regular cone (in FIG. 3 the two dot lines) intersects the outer surface of the outer bulb 10. In the installed position of the lamp, this partial coating 9 covers at least the region which, starting from the middle of the connecting line (shown as a dot-and-dash line in FIG. 3) of the two electrode tips Erdbeschleunigungsvektor g is a rotary cone with a Öffhungswinkel of at least 10 degrees on the outer bulb 10 is formed.

In Fig. 4 is shown in cross-section, along the center of the burner, in Fig. 3, the lamp of FIG. 3 (2nd embodiment) with contours of the lamp cap. The coating 8 is at least light-absorbing and consists of at least a first part 11, two second parts 12, 13 and a third part 9. The parts 9, 12 and 13 do not form a closed surface.

The third part 9 of the coating 8 is a filter consisting of a material which transmits blue or infrared light and reflects or absorbs the remaining portion of the spectrum, or reflects or absorbs the entire spectrum. The filter has the following filter parameters: It reflects or absorbs predominantly in the wavelength range from 420 to 830 nm, and transmits wavelengths below or above this range.

The degree of transmittance of the filter with respect to wavelengths below 420 nm or above 830 nm is> 5% in each case.

Claims

CLAIMS:

1. high-pressure discharge lamp, at least with a burner (1) having a discharge chamber, with two in the discharge chamber (2) extending electrodes (3,

4), - with a Gasfullung in the discharge chamber (2), the at least one

Noble gas and a metal halide mixture containing, with at least partially light-absorbing, at least partial

Coating (8), in the installation position of the lamp from the middle of the line connecting the two electrode tips starting with the acceleration due to gravity Ge a rotary cone with an opening angle of at least 5 degrees on the

Discharge chamber (2) and / or an outer bulb (10) covers.

2. High-pressure discharge lamp according to claim 1, characterized in that the coating (8) allows portions of blue light to pass better than other portions of the visible light.

3. High-pressure discharge lamp according to claim 1, characterized in that the coating (8) allows portions of the spectrum, in particular infrared components, to pass better than other portions of the light.

4. High-pressure discharge lamp according to claim 1, characterized in that it also has at least one burner (1) attached to the outer bulb (10) and a return conductor (7) which is arranged outside of the outer bulb (10).

5. High-pressure discharge lamp according to claim 1, characterized in that the light-absorbing coating (8) also comprises at least a first part

(11) and two second parts (12, 13), and these are arranged on a part of the surface of the outer bulb (10), wherein the first part (11) of the coating is a ring or a segment of a ring which is arranged close to the socket is, wherein said first part (11) at least from a location which forms an angle A of about 45 ° with the perpendicular to the outer bulb (3) at the intersection with the middle of the distance between the electrodes (3, 4), at least until extends to a location which forms an angle B of about 65 ° with this perpendicular, the vertices of A and B lying on the longitudinal axis of the burner (1), the second part (12, 13) of the coating (8) a Has strip shape and rests with its socket near end on the first part (11) gap-free, the two second parts (12, 13) which extend parallel to the longitudinal axis of the burner (1) and opposite side edges (12 \ 13 ") having a Include angle C of nearly 195 °, and facing side edges (12 ", 13") enclosing an angle D of about 115 °, wherein the vertices of C and D lie on the longitudinal axis of the burner (1), wherein a third part (9) with its socket near end on the first part (11) rests gap-free and the two side edges (9 ", 9") against the side edges (12 ", 13") lie gap-free.

6. lighting unit, the at least one headlamp with at least one high-pressure discharge lamp according to the claims 1 to 5 contains.