WO2009092400A1

WO2009092400A1 - Illumination device

Info

Publication number: WO2009092400A1
Application number: PCT/EP2008/003368
Authority: WO
Inventors: Van Quang Nguyen
Original assignee: We-Ef Leuchten Gmbh & Co. Kg
Priority date: 2008-01-25
Filing date: 2008-04-25
Publication date: 2009-07-30
Also published as: EP2245362A1; EP2245362B1; DE102008006229B4; DE102008006229A1

Abstract

An illumination device, particularly street illumination device, for illuminating an evaluation field (24), comprises a base body (4) on which a plurality of light emitting diode units (8, 10) are arranged, each comprising a light emitting diode (14) and a beam forming device associated to the light emitting diode. According to the invention, the light emitting diode units (8, 10) are designed for illuminating substantially the entire evaluation field (24) associated with the illumination unit.

Description

WE-EF LEUCHTEN GmbH & Co. KG 049/021 WO 23.04.2008 cw / st

lighting device

The invention relates to a lighting device, in particular street lighting device, the type mentioned in the preamble of claim 1 for illuminating a weighting field. With the considerable improvement in the efficiency of light emitting diodes, there are many new fields of application for light emitting diodes. For example, high power light emitting diodes are increasingly used in the automotive and lighting industries. Among other things, they are particularly advantageous because they contain substances that are harmful to the environment or to health, in particular mercury, or not to any appreciable extent.

However, due to the compared to fluorescent, halomoldall- steam or sodium vapor high-pressure lamps, the luminosity of LEDs is lower, so that instead of one of the aforementioned conventional lamps, a plurality of light-emitting diodes is required to achieve the same illuminance. Lighting devices of the type in question for illuminating a weighting field are known. They have a main body on which a plurality of light-emitting diode units is arranged, each one Have light emitting diode and a beam extension device. The beam shaping device can be formed by a lens or lens arrangement and / or by a reflector. In the aforementioned lighting devices, it is known to arrange the light-emitting diode units on the base body in such a way that they illuminate the surface to be illuminated, for example a road, essentially vertically. The lighting fields of the individual light-emitting diodes add up to a total lighting field. Depending on the shape of the individual illumination fields, this results in light distributions that are unfavorable for the particular application, for example street lighting. It is particularly disadvantageous that the maximum of the illuminance is usually in the main beam direction, that is, directly under the luminaire in the case of a street lamp, and the illuminance decreases sharply laterally relative to the main beam direction. This leads to an illumination efficiency that is considerably lower than the illumination efficiency of, for example, a conventional high-pressure gas discharge lamp.

In lighting devices of the type in question, it is also known to align the individual light-emitting diode units relative to the base body individually. In this way, a more uniform illumination of the evaluation field is possible, since the light of the individual light-emitting diode units can be targeted to the areas in which it is needed to achieve a uniform illuminance in the evaluation field. Moreover, it is possible to at least partially minimize stray light in this way. A disadvantage of these known lighting devices is that they are due to the indi- viduellen alignment of the individual light emitting diode units are expensive to manufacture, installation and maintenance. Another disadvantage of these known lighting devices is that the failure of individual LEDs leads to "holes" in the light distribution and thus the illumination of the evaluation field with a uniform illuminance is no longer guaranteed.

The invention has for its object to provide a lighting device of the type in question, which does not have the disadvantages of the known lighting devices, which thus ensures a substantially uniform illuminance in the illumination of the evaluation field and their manufacture, installation and maintenance is simplified.

This object is achieved by the teaching defined in claim 1.

The basic idea of the teaching according to the invention is to substantially completely illuminate the evaluation field with each of the light emitting diode units. Thus, according to the invention, the illumination field of a light-emitting diode unit, that is to say that surface which is illuminated by the light-emitting diode unit, essentially coincides with the evaluation field, that is to say the surface which is to be illuminated overall by the illumination device. Thus, each light emitting diode unit illuminates the evaluation field with a substantially uniform illuminance. If, for example, n light-emitting diode units are provided on the illumination device, then each light-emitting diode unit contributes the l / th part to the total luminous flux. The total illuminance in the evaluation field thus results from the addition of the illuminance levels of the individual light-emitting diode units. For illuminating, for example, a substantially rectangularly delimited evaluation field, it is possible, for example and in particular, to provide light-emitting diode units in which the beam-shaping device has a lens arrangement with at least one non-rotationally symmetrical lens which is symmetrical with respect to at least one plane of symmetry. By appropriate shaping of the lens almost any illumination fields are possible, wherein the shape of the lens is dependent on the laws of the beam optics of the desired illumination field.

Since, according to the invention, each of the light-emitting diode units essentially illuminates the entire evaluation field, a particular advantage of the invention is that all light-emitting diode units can be arranged with the same orientation on the base body of the illumination device. This simplifies the manufacture, assembly and maintenance, so that the manufacturing, installation and maintenance costs are reduced.

A further advantage of the teaching according to the invention is that it is possible to use a uniform lens type for all light-emitting diode units. In this way, the tools necessary for the production of all lenses of the illumination device according to the invention are required only once, so that the development and planning costs are reduced. It also simplifies maintenance by eliminating the possibility of confusing lens types when using different lens types.

If a light-emitting diode unit fails at the illumination device according to the invention, the illuminance in the evaluation field remains evenly, since each of the light-emitting diode units according to the invention essentially illuminates the entire evaluation field. It only slightly reduces the overall light intensity. In this way, overall, a higher reliability is achieved, so that the maintenance intervals can be extended and the maintenance costs can be reduced.

By appropriate shaping of the respective lens, idealized light intensity distributions can also be achieved, so that, for example, in the case of street lighting, the mast distances can be increased in comparison to conventional street lighting devices.

A further advantage of the teaching according to the invention is that the evaluation field can be illuminated in a precisely focused manner, so that the scattered light arising when the evaluation field is illuminated is reduced. This not only reduces the so-called "sky pollution", but also the annoyance of residents in residential areas. In addition, there is a better illumination efficiency compared to conventional street lighting devices.

A further advantage of the teaching according to the invention is that the illuminance with which the evaluation field is illuminated can be adjusted with the aid of relatively simple control devices without impairing the uniformity of the illumination. For this purpose, it is only necessary to connect or disconnect individual light emitting diode units or groups of light emitting diode units. In this way, the illuminance can be adapted to the respective requirements, so that results in times in which a lower illuminance is sufficient, a significant energy savings.

A particular advantage of the teaching according to the invention is that lighting devices according to the invention can be retrofitted, provided that future light emitting diodes with higher efficiency will be available. If a lighting device according to the invention is designed, for example, to achieve a desired illuminance in the evaluation field by using a specific number of light-emitting diode units, the number of light-emitting diode units can be halved while maintaining the illuminance in the evaluation field, for example, provided future light-emitting diodes with correspondingly increased efficiency are available stand. Since, according to the invention, the individual LED units for illumination are formed essentially in the overall evaluation field, it is also possible according to the invention to reduce the plurality of light emitting diode units of a lighting device to a single light emitting diode unit, provided that light emitting diodes with correspondingly increased efficiency will be available in the future. An advantageous development of the teaching according to the invention provides that the lens arrangement has at least one lens. The shape of the lens is chosen according to the laws of the beam optics so that the resulting illumination field substantially corresponds to the evaluation field. Corresponding calculation methods of the optics are generally known to the person skilled in the art and are therefore not explained in more detail here.

For illuminating a, for example, substantially rectangularly-limited evaluation field, it is advantageous if the lens is a non-rotationally symmetrical lens, which is preferably symmetrical with respect to at least one plane of symmetry, as provided by developments of the teaching according to the invention.

Other developments of the teaching of the invention provide that the light-emitting diode radiates into a recess formed in the lens and / or that the recess is essentially hemispherical, as provided by advantageous developments of the teaching according to the invention. In these embodiments, refractive effects at the air / lens interface are particularly well calculable, so that the lens design is simplified.

Another development of the teaching according to the invention provides that the evaluation field is a valuation field delimited by a straight line. This embodiment is particularly well suited for the realization of street lighting, since a band-shaped light distribution can be achieved, for example, on a road, in a particularly simple manner by juxtaposing the lighting fields of several lighting devices according to the invention.

An advantageous development of the aforementioned embodiment provides that the evaluation field is limited substantially rectangular.

Another development of the teaching of the invention provides that the light-emitting diode units are grid-like, in particular rectangular grid-like manner, arranged on the base body. In this way, the base body of the illumination device according to the invention can be designed to be particularly simple and thus cost-effective.

Another advantageous development of the teaching according to the invention provides that the lens is shaped so that the associated light-emitting diode unit illuminates a non-rotationally symmetrical illumination field. This embodiment is particularly well suited if the evaluation field to be illuminated is a non-rotationally symmetric, for example Eckart limited valuation field is.

An extremely advantageous development of the teaching of the invention provides that the lens is made of plastic. In this embodiment, the lens can be produced in a particularly simple manner, for example in an injection molding process, wherein the geometric shape of the lens is limited exclusively by the technical characteristics of the manufacturing process. In this embodiment, there are thus virtually unlimited freedom with regard to the shaping of the lens and thus the design of the illumination field of the respective light-emitting diode unit.

An advantageous development of the aforementioned embodiment provides that the plastic is acrylic glass and or polycarbonate. Corresponding plastics can be processed relatively easily and are relatively inexpensive.

The invention will be explained in more detail with reference to the attached highly schematic drawing, in the embodiments of an inventive

Lighting device are shown. In this case, all described, shown in the drawings and claimed in the claims characteristics taken alone or in any combination with each other the subject of the invention, regardless of their summary in the claims and their dependency and regardless of their description or representation in the drawing.

It shows:

1 is a perspective view of an embodiment of a lighting device according to the invention in the form of a street lamp, - S -

Fig. 2 in comparison with FIG. 1 enlarged scale a side view of the street lamp according to FIG. 1,

3 in comparison with FIG. 1 enlarged Maß- rod a bottom view of the street lamp of FIG. 1,

4 shows a first side view of a light-emitting diode unit of the street light according to FIG. 1 for clarifying the radiation path in the longitudinal direction of the road,

5 is a side view of FIG. 4 offset by 90 ° further side view of the LED unit of FIG. 4 to illustrate the beam path in the transverse direction,

6A-6G various examples of lighting situations on roads,

Fig. 7 is a bottom view of a second

Embodiment of a lighting device according to the invention and

8 shows a side view of the illumination device according to FIG. 7.

In Fig. 1, a first embodiment of a lighting device according to the invention in the form of a street lamp 2 for illuminating one of the street lamp 2 associated evaluation field is shown. The street lamp 2 has a housing-like base body 4 which is fixed to an upper end of a mast 6.

2, which shows a side view of the street lamp 2 according to FIG. 1, it can be seen that a plurality of light-emitting diode units is arranged in the base body 4, which are explained in more detail below and of which in Fig. 2, only two light emitting diode units are denoted by the reference numerals 8, 10. The light-emitting diode units 8, 10 each have a light-emitting diode and a beam-shaping device assigned to the light-emitting diode in the manner explained in more detail below with reference to FIGS. 4 and 5.

From FIG. 3, which shows a view from below of the streetlight 2, it can be seen that the light-emitting diode units 8, 10 are arranged on the base body 4 in a grid-like manner, in the embodiment shown in a rectangular grid.

From Fig. 3 it is further apparent that the light-emitting diode units 8, 10 are arranged in the same orientation on the base body 4. 4 shows a first side view of the light-emitting diode unit 8, which has a light-emitting diode 14 arranged on a diode base body 12. A control and voltage supply circuit of the light-emitting diode 14 is formed in a manner well-known to the person skilled in the art and will therefore not be explained in more detail here. The light-emitting diode main body 12 is arranged on a heat sink 18 for cooling.

The light-emitting diode unit 8 has a beam shaping device, which in this exemplary embodiment has a lens arrangement which in this embodiment consists of a single lens 16. In the illustrated embodiment, the street lamp 2 is provided for illuminating a rectangular limited evaluation field. Since the light-emitting diode units 8, 10 of the street light 2 according to the invention are designed to illuminate essentially the entire evaluation field, the lens 16 is shaped such that the light-emitting diode unit 8 illuminates a rectangular illumination field. For illumination a rectangle-like illumination field, the lens 16 is non-rotationally symmetrical, but symmetrical to a symmetry plane 20 indicated in Fig. 4 by a dash-dotted line. The shape of the lens 16 is thus dependent on the shape of the illumination field to be illuminated. The determination of the shape of the lens 16, which takes place according to the laws of ray optics and as a function of the distance of the light-emitting diode unit 8 from the evaluation field to be illuminated, is well known to the person skilled in the art and will therefore not be explained in detail here.

In the illustrated embodiment, the lens 16 is made of a plastic, namely acrylic glass. Characterized in that the lens 16 is made of plastic, given the shape of the lens 16 and its adaptation to the shape of the respective evaluation field almost arbitrary freedoms.

In the illustrated embodiment, the light emitting diode 14 radiates into a hemispherical recess 22 formed in the lens 16, wherein the beam path of rays emanating from the air / plastic interface of the recess 22, in Fig. 4 is indicated.

FIG. 5 shows a side view of the light-emitting diode unit 8 with the lens 14 offset by 90 ° relative to the side view according to FIG. 4, wherein the beam path of rays emanating from the air / plastic interface of the recess 22 is again indicated.

6 shows different lighting situations with different evaluation fields.

FIG. 6A illustrates a lighting situation on a six-lane road in which a rectangular evaluation field 24 is illuminated by means of the street light 2. The valuation field 24 covers three Strip of the six lane road, wherein the remaining three strips a corresponding evaluation field 24 'is assigned, which is illuminated by a corresponding street lamp. FIG. 6B illustrates the illumination of a three-lane road in a valuation field 24 by means of a street lamp 2 according to the invention arranged on one side of the road.

FIG. 6C illustrates an illumination of the three-lane road according to FIG. 6B by means of street lights arranged on both sides of the road, with a roadside evaluation field 24 and a street light arranged on the opposite roadside assigned a corresponding evaluation field 24 ' is.

FIG. 6D illustrates a lighting situation similar to the lighting situations according to FIG. 6B, in which a plurality of streetlights according to the invention are staggered in the longitudinal direction of the road, so that the evaluation fields 24, 24 "assigned to them follow one another in the longitudinal direction of the road.

Fig. 6E corresponds to Fig. 6B, wherein the street to be illuminated is a two-lane street. FIG. 6F corresponds to FIG. 6C, wherein the road to be illuminated again is a two-lane road.

FIG. 6G corresponds to FIG. 6D, wherein the street to be illuminated again is a two-lane street.

According to the invention, the evaluation field associated with a streetlight 2 is substantially completely illuminated with each of the light-emitting diode units 8, 10, so that the illumination field of a light-emitting diode unit 8, 10, that is, the area that is illuminated by the light-emitting diode unit, substantially coincident with the evaluation field 24, that is, the area that is to be lit by the street lamp 2 as a whole.

Accordingly, the light-emitting diode units 8, 10 can be arranged in the same orientation on the base body 4, so that an individual alignment of the light-emitting diode units 8, 10 is omitted during assembly. A failure of one of the light-emitting diode units 8, 10 accordingly only leads to a reduction in the illuminance, but the uniformity of the illumination of the evaluation field 24 is maintained. Fig. 7 shows a bottom view of a further embodiment of a street lamp 2 according to the invention, which differs from the embodiment of FIG. 3 in that instead of ten light-emitting diode units 8, 10 in the embodiment of FIG. 3, sixteen light-emitting diode units 8, 10 are provided are arranged along a square-shaped grid.

8 shows a side view of the exemplary embodiment according to FIG. 7. Since the light-emitting diode units 8, 10 are necessarily offset slightly from one another on the main body 4, as is apparent from FIGS. 3 and 7, the illumination fields of the individual light-emitting diode units 8, 10 are However, this offset is so small measured by the size of the associated evaluation field 24 that the LED units for illumination substantially the entire Assessment field 24 are formed.

Claims

claims

1. lighting device, in particular street lighting device, for illuminating a weighting field,

with a base body, on which a plurality of light-emitting diode units is arranged, each of which has a light-emitting diode and a light-emitting diode associated beam shaping device,

characterized,

in that the light-emitting diode units (8, 10) are designed to illuminate essentially the entire evaluation field (24) assigned to the illumination device.

2. Lighting device according to claim 1, characterized in that the beam shaping device has a lens arrangement with at least one lens (16) up.

3. Lighting device according to claim 2, characterized in that the lens (16) is a non-rotationally symmetric lens.

4. Lighting device according to claim 2 or 3, characterized in that the lens (16) with respect to at least one plane of symmetry (20) is symmetrical.

5. Lighting device according to one of claims 2 to 4, characterized in that the light-emitting diode (14) radiates into a formed in the lens (16) Aufnehmung (22).

6. Lighting device according to claim 5, characterized in that the recess (22) is substantially hemispherical.

7. Lighting device according to one of claims 1 to 6, characterized in that the evaluation field (24) is a limited by a line straight lines evaluation field.

8. Lighting device according to claim 7, characterized in that the evaluation field (24) is limited substantially rectangular.

9. Lighting device according to one of the preceding claims, characterized in that the

Light-emitting diode units (8, 10) grid-like, in particular rectangular grid-like, are arranged on the base body (4).

10. Lighting device according to one of claims 2 to 9, characterized in that the lens (16) is shaped such that the associated light-emitting diode unit (8) illuminates a non-rotationally symmetrical illumination field.

11. Lighting device according to one of claims 2 to 10, characterized in that the lens (14) consists of plastic.

12. Lighting device according to claim 11, characterized in that the plastic is acrylic glass and / or polycarbonate.