Light having a cover panel

Abstract

A lamp, comprising at least one light source (3), arranged in a housing (1) having at least one light exit opening, and at least one reflector (4), which is shaped in such a way that the light coming from the light source (3) is divided into at least two light beams, the light exit opening being at least partially covered by a cover panel (5), which has two surface portions (5a, 5b) on which the respectively corresponding light beams impinge, the surface portions (5a, 5b) being shaped in such a way that the predominant part of the light beams that is respectively directed onto a surface portion (5a, 5b) impinges on the surface portion (5a, 5b) at an angle of incidence which is less than 60°, in order to reduce the reflections from the cover panel (5).

Claims

1. A lamp, comprising: a housing having at least one light exit opening; at least one light source arranged in the housing; and at least one reflector configured to divide light coming from each of the at least one light source into at least two separate light beams, the at least one reflector comprising two portions, each having a shape of a hollow funnel for receiving one of the at least two separate light beams, wherein each funnel widens from the at least one light source towards a light exit opening of the funnel that is directed towards the at least one light exit opening of the housing, wherein the at least two separate light beams exit the housing through the at least one light exit opening, where a light intensity between the separate light beams is reduced; a cover panel configured to at least partially cover the light exit opening of each funnel, the cover panel having two surface portions on which the respectively corresponding light beams impinge, the surface portions shaped such that the at least two separate light beams that are respectively directed onto a respective of the at least two surface portions impinge on the surface portion at an angle of incidence which is less than 60°, in order to reduce the reflections from the cover panel wherein each of the surface portions of the cover panel has in cross section the form of a curve with an extremum, the curve being asymmetrical with respect to a center of the light exit opening of the funnel of the reflector that is at least partially covered by the respective surface portion of the cover panel.

2. The lamp as claimed in claim 1, wherein the part of the light beam that impinges on one of the surface portions at the angle of incidence comprises more than 75% of the stream of light directed onto the surface portion.

3. The lamp as claimed in claim 1, wherein the surface portion is shaped in such a way that the light beam incident on it impinges with an angle of incidence of less than 45°.

4. The lamp as claimed in claim 1, wherein the surface portion is convex, concave, arched or curved or has the form of a wave with an apex extending in a linear or arcuate manner.

5. The lamp as claimed claim 1, wherein the lamp comprises one or more reflectors, which produce more than two light beams, and the cover panel has a number of assigned surface portions corresponding to the number of light beams.

6. The lamp as claimed in claim 1, wherein the lamp has a number of reflectors arranged in a row with light sources respectively assigned to them, the light beams that come from the reflectors being superposed on one another.

7. The lamp as claimed in claim 1, wherein the reflector has the form of a bent tube having two light exit openings at the ends, a light source being arranged in the middle of the tube.

8. The lamp as claimed in claim 1, wherein the light source is an LED, an LED array or an OLED.

9. The lamp as claimed in claim 1, wherein the cover panel is formed in a rectangular or round manner and comprises a wavy form with two or more wave maxima.

10. The lamp as claimed in claim 1, wherein the cover panel is provided with an antireflective coating or is treated so as to be antireflective.

11. The lamp as claimed in claim 1, wherein the part of the light beam that impinges on one of the surface portions at the angle of incidence comprises more than 75%, more than 90% or more than 95% of the stream of light directed onto the surface portion.

12. The lamp as claimed in claim 1, wherein the surface portion is shaped in such a way that the light beam incident on it impinges with an angle of incidence of less than 45°, less than 30°, less than 20° or less than 10°.

13. The lamp as claimed in claim 1, wherein the light source is an LED, an LED array or an OLED.

14. A lamp, comprising: a housing having at least one light exit opening; at least one light source arranged in the housing; and at least one reflector configured to divide light coming from each of the at least one light source into at least two separate light beams, the at least one reflector comprising two portions, each having a shape of a hollow funnel for receiving one of the at least two separate light beams and each widening from the light source towards an annular light exit opening of the funnel, wherein the reflector further comprises at least two light exit openings which are substantially parallel to each other, wherein each of the at least two separate light beams passes through one of the two portions of the reflector and through one of the two light exit openings of the reflector so that a light intensity between the separate light beams is reduced; a cover panel configured to at least partially cover the light exit opening of each funnel, the cover panel having two surface portions on which the respectively corresponding light beams impinge, the surface portions shaped such that the at least two separate light beams that are respectively directed onto a respective of the at least two surface portions impinge on the surface portions at an angle of incidence which is less than 60°, in order to reduce the reflections from the cover panel wherein each of the surface portions of the cover panel has in cross section the form of a curve with an extremum, the curve being asymmetrical with respect to a center of the light exit opening of the funnel of the reflector that is at least partially covered by the respective surface portion of the cover panel.

15. The lamp as claimed in claim 14, wherein that the part of the light beam that impinges on one of the surface portions at the angle of incidence comprises more than 75% of the stream of light directed onto the surface portion.

16. The lamp as claimed in claim 14, wherein the surface portion is shaped in such a way that the light beam incident on it impinges with an angle of incidence of less than 45°.

17. The lamp as claimed in claim 14, wherein the surface portion is convex, con-cave, arched or curved or has the form of a wave with an apex extending in a linear or arcuate manner.

18. The lamp as claimed in claim 14, wherein the lamp comprises one or more reflectors, which produce more than two light beams, and the cover panel has a number of assigned surface portions corresponding to the number of light beams.

19. The lamp as claimed in claim 14, wherein the lamp has a number of reflectors arranged in a row with light sources respectively assigned to them, the light beams that come from the reflectors being superposed on one another.

20. The lamp as claimed in claim 14, wherein the reflector has the form of a bent tube having two light exit openings at the ends, a light source being arranged in the middle of the tube.

21. The lamp as claimed in claim 14, wherein the cover panel is formed in a rectangular or round manner and comprises a wavy form with two or more wave maxima.

22. The lamp as claimed in claim 14, wherein the cover panel is provided with an antireflective coating or is treated so as to be antireflective.

23. The lamp as claimed in claim 14, wherein the part of the light beam that impinges on one of the surface portions at the angle of incidence comprises more than 95% of the stream of light directed onto the surface portion.

24. The lamp as claimed in claim 14, wherein the surface portion is shaped in such a way that the light beam incident on it impinges with an angle of incidence of less than 10°.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features, properties and advantages of the present invention emerge from the following description of an exemplary embodiment on the basis of the appended drawing, in which

(2) FIG. 1 shows a lamp according to an exemplary embodiment of the invention having a cover panel in cross section;

(3) FIG. 2 shows the lamp according to the embodiment shown in FIG. 1 in a view perspectively from below; and

(4) FIG. 3 shows two graphs, which show the degree of reflection and the transmission in dependence on the angle of incidence on a transparent surface for light that is polarized perpendicularly (FIG. 3a) and in parallel (FIG. 3b).

DETAILED DESCRIPTION OF THE DRAWINGS

(5) The lamp according to the invention is described on the basis of an exemplary embodiment with reference to FIGS. 1-3. The lamp 1 according to the embodiment shown comprises a housing 1, on the upper side of which an LED module housing 2 is arranged. A number of reflectors 4 are fastened next to one another on the LED module housing 2.

(6) The reflectors 4 of a tubular form respectively comprise a tube which has a constriction in the middle in the longitudinal direction. In the region of the constriction, a light source 3, which may for example comprise one or more LEDs, is arranged on the LED module housing 2. The tube widens in a funnel-shaped manner from the constriction to the annular light exit openings 6. A proportion of at least 10% of the overall stream of light emitted by the LEDs can exit from the light exit openings 6 without being reflected from the reflector surface as a light beam. The reflective surface inside the tube is partially or completely faceted.

(7) As described in further details in DE 10 2010 007 774, this “3-zone reflector” produces as a result of its tubular form two light beams, which exit at the light exit openings of each reflector 4. The arrangement of a number of reflectors parallel to one another has the effect of superimposing on one another the light beams that exit from the light exit openings 6 that are arranged on the same side with respect to the longitudinal axis of the lamp. However, the light intensity emitted directly underneath the light source is reduced, since light emitted perpendicularly downward from the light source 3 impinges on the reflector 4 and, inter alia, exits laterally at a shallow angle from the respective light exit opening 6. The radiation characteristic of the lamp 1 is such that a significant proportion of light is emitted in the direction of the two longitudinal sides of the lamp 1. Accordingly, a large proportion of light exits at a shallow angle from the light exit openings 6.

(8) A cover panel 5 is arranged on the underside of the housing 1. The cover panel 5 may be produced from glass or plastic. As can be seen in particular in FIG. 1, the cover panel 5 comprises two wavy surface portions 5a, 5b. The apexes of the waves of the surface portions 5a, 5b extend parallel to the longitudinal side of the lamp 1, as can be seen in FIG. 2. The two surface portions 5a, 5b are connected to each other by a wave trough. As stated above, in the wave trough relatively little light passes through the cover panel 5, since the light exit openings 6 of the reflector 4 are arranged to the sides thereof. On account of the arched surface of the two surface portions 5a, 5b, rays coming directly from the light source 3 and rays coming from the reflector surface that exit from the light exit openings 6 of the lamp at a small angle impinge at a greater angle on the cover panel 5 than in the case of a flat cover panel 5 oriented parallel to the light exit openings 6. The lowering of the angle of incidence θ.sub.i allows reflections from the cover panel 5 to be reduced in a manner according to the dependence that is represented in FIGS. 3a and 3b.

(9) As can be seen in FIG. 3, for rays impinging on a cover panel 5, the degree of reflection (R.sub.⊥=polarized perpendicularly, R.sub.∥=polarized in parallel) increases with increasing angle of incidence, i.e. increasing angle between the normal to the surface and the direction of incidence of the light. On account of the arching of the cover panel 5, however, the degree of reflection can be reduced in comparison with a planar or flat cover panel.

(10) In addition, the cover panel 5 comprises a small height, so that the proportion of stray light emitted to the rear side of the lamp 1 from the cover panel 5 remains small.

(11) Numerous modifications can be made to the lamp shown by way of example without departing from the scope of the invention. In particular, the rim of the housing of the lamp 1 shown in FIGS. 1 and 2 may be extended in the direction transversely to the cover panel up to the height of the apexes of the waves of the cover panel 5, so that the cover panel 5 does not at any point project beyond the light exit opening of the lamp 1 formed by the rim of the cover panel 5, in order to achieve a 0% emission into the region to the rear of the lamp 1 or into the sky.

(12) The scope of protection of the invention is not limited to the examples given hereinabove. The invention is embodied in each novel characteristic and each combination of characteristics, which includes every combination of any features which are stated in the claims, even if this feature or combination of features is not explicitly stated in the examples.