WO2012159861A1

WO2012159861A1 - A lens, a lighting module having the lens and an indoor wall washer

Info

Publication number: WO2012159861A1
Application number: PCT/EP2012/058153
Authority: WO
Inventors: Aiai Li; Huijun XIONG; Peng Chen; Tingming LIU
Original assignee: Osram Ag
Priority date: 2011-05-20
Filing date: 2012-05-03
Publication date: 2012-11-29
Also published as: CN102788315A; CN102788315B

Abstract

The present invention relates to a non-rotational symmetric lens (L) comprising a lens mainbody (M) and a lens base (S) supporting the lens mainbody (M). The lens mainbody (M) comprises an outer surface emitting light and an inner surface receiving light from a light source, wherein the outer surface comprises a first asymmetric curve surface (A) having a first continuous curve shape; the inner surface comprises a second rotational symmetric curve surface having a second continuous curve shape; the lens mainbody (M) further comprises a third curve surface (C) configured to at least partially reflect light from the second curve surface (B) to the first curve surface (A). In addition, the present invention relates to a lighting module mounted with such lens (L) and an indoor wall washer formed by an array comprising a plurality of the lighting modules. The lens (L) according to the present invention may improve the light efficiency, further restrains glare and may obtain a good optical performance.

Description

A Lens, a Lighting Module Having the Lens and an Indoor Wall

Washer

Technical Field

The present invention relates to a non-rotational symmetric lens, a lighting module installed with such lens and an indoor wall washer formed by an array comprising a plurality of such lighting modules .

Background Art

Currently, the wall washer is used more and more for architectural decorative illumination and indoor and outdoor local illumination. In the prior art, on the one hand, the downlight or the LED module in the downlight may be tilted to be used as an indoor wall washer. Both methods require a sufficient space reserved for tilting the downlight or the LED module. As the lightening apparatus is usually mounted on the ceiling board, the whole harmonization of the ceiling board is being affected, and only the light distribution with poor uniformity can be obtained on a projection wall. The light usage ratio on the projection wall is greatly affected since a part of the light emitted from the light source is absorbed or reflected by its own structure.

On the other hand, the indoor wall washer can also be achieved by the combination of multiple lenses and an asymmetry reflector. In such wall washer, apart from a primary lens, one high light efficiency lens made from PMMA is additionally mounted, whose main function is to allocate secondarily the light emitted from a lighting part, in the asymmetric reflector designed as a reflection cup, so that a desired light distribution may be obtained on the projection wall. But the disadvantage of this design is that such structure of combining double lenses with an asymmetric reflector is relatively complex and costly. Therefore, it is urgently to improve the structure of the lighting module forming the wall washer, especially the lens of the lighting module, on the basis of the prior art.

Summary of the Invention

In order to solve the above problem, it is provided in the present invention a novel lens, a lighting module with such lens, and an indoor wall washer formed by an array by combining a plurality of such lighting modules.

The first object of the present invention is accomplished via a lens as follow; i.e. the lens comprises a lens mainbody and a lens base supporting the lens mainbody. The lens mainbody comprises an outer surface emitting light and an inner surface receiving light from a light source, wherein the outer surface comprises a first asymmetric curve surface having a first continuous curve shape; the inner surface comprises a rotational symmetric second curve surface having a second continuous curve shape; the lens mainbody further comprises a third curve surface configured to at least partially reflect light from the second curve surface to the first curve surface.

The inventive concept of the present invention lies in that the light emitted from the light source is received by the rotational symmetric second curve surface such—s-θ- that the light passes through the second curve surface and at least a part of the light is further reflected using the third curve surface, and the light is finally shot out through the asymmetric first curve surface, thus realizing the effect of uniform light distribution that only can be accomplished by combining the secondary lens with the reflection cup in the prior art. In the present invention, the requirement to uniform light distribution is satisfied through a specific contour configuration of the lens, and moreover, it avoids the disadvantages of low usage ratio and high cost brought by tilting the lighting module or the secondary lens in the prior art and reduces generation of glare at the same time. Preferably, the outer surface of the lens further comprises a fourth surface adjoining the first curve surface for reducing glare and improving the light uniformity. And advantageously, the inner surface of the lens further comprises a fifth surface adjoining the second curve surface for reducing generation of glare and improving the light uniformity.

Preferably, the fifth surface and the second curve surface jointly define a space for accommodating the light source. Such design may reduce generation of glare.

According to a preferred solution in the present invention, the first curve surface is a 10^th-order polynomial surface added to a conic. Particularly preferably, a contour of the first curve surface may be defined by the following equations:

, wherein m+n≤10, and k is the conic constant, c is the curvature radius, Cj is the coeffi-

(m + n +m + 3n / 2 + 1

cient of the monomial x^my"" , and - J In a par- ticularly preferred solution, m+n≤4, for instance, m=0, n=l, 2, 3 or 4.

According to a preferred solution in the present invention, the second curve surface is a polynomial aspheric surface. In an advantageous embodiment of the present invention, a rotational symmetry line of the second curve surface is offset with respect to an optical axis of the light source so as to produce a polarization effect. Particularly preferably, a contour of the second curve surface may be defined by the following equations:

s the conic constant , and c is the curvature radius. In a particularly preferred solution, n=2 or 3. According to a preferred solution in the present invention, the third curve surface is a total internal reflection surface. With the total internal reflection property of the third curve surface, the light loss may be reduced and the light efficiency may be improved .

According to a preferred solution in the present invention, the lens base has two side walls and one arc wall jointly defining a space for surrounding the main lens body.

Advantageously, in the lens base, inner side surfaces of the side walls faced to the first curve surface and an inner side surface of the arc wall faced to the third curve surface. Preferably, the inner side surfaces of the side walls are total internal reflection surfaces. The inner side surfaces of the side walls reflect the light at both sides of the lens mainbody so as to improve the efficiency better.

In addition, the fourth surface and the fifth surface may be advantageously plane surfaces forming certain angles with the optical axis.

Another object of the present invention is accomplished via a lighting module having lenses of the preceding type. As the lighting module has a non-rotational symmetric lens, the light usage ratio can be improved, and the effects of good light uniformity and reduction of glare can be obtained. The lighting module according to the present invention replaces the structure of combining the secondary lens with the reflector using a single lens, thus the advantages of small size and simple structure are prominently reflected.

Another object of the present invention is accomplished via an indoor wall washer formed by an array comprising a plurality of lighting modules of the above type. Though such wall washer maintains the basic contour of traditional downlight, it also has the function of the indoor wall washer, may be applied in many fields, such as illumination in shop and gallery. A uniform light distribution with a small unified glare rating ( UGR ) may be obtained on the projection wall using such indoor wall washer.

Brief Description of the Drawings The drawings constitute a portion of the Description for further understanding of the present invention. These drawings illustrate the embodiments of the present invention and explain the principle of the present invention together with the Description. In the drawings , Fig. 1 is a sectional view of a lighting module according to the present invention;

Fig. 2 is a bottom view of the lighting module according to Fig. 1;

Fig. 3 is a top view of the lighting module according to Fig. 1; Fig. 4 is a light intensity distribution view of the lighting module according to the present invention;

Fig. 5 is a light distribution view of the lighting module according to the present invention;

Fig. 6 is a portion of X-orientation in the light distribution view according to Fig. 5;

Fig. 7 is a portion of Y-direction in the light distribution view according to Fig. 5;

Fig. 8 is an indoor wall washer according to the present invention; Fig. 9 is a unified glare rating distribution view of the indoor wall washer according to the present invention.

Detailed Description of the Embodiments

Fig. 1 is a sectional view of a lighting module according to the present invention. It can be seen from Fig. 1 that the lighting module according to the present invention with a lens L specially designed according to the present invention. The lens L consists of two portions: a lens mainbody M and a lens base S.

An outer surface of the lens mainbody M comprises a first curve surface A and a fourth surface E, and an inner surface of the lens L according to the present invention comprises a second curve surface B and a fifth surface F. A light source mounted on a circuit board may be placed in a space R defined by the second curve surface B and the fifth surface F. A third curve surface C configured to at least partially reflect light from the second curve surface B to the first curve surface A is provided with respect to the first curve surface A and is connected with the fourth surface E. The third curve surface C is designed to be a total internal reflection surface in order to realize the reflection effect better.

The first curve surface A is an asymmetric curve surface and is a 10^th-order polynomial surface added to a conic. A contour of the first curve surface A preferably is defined by the following equa-

tions:

, wherein m+n≤10, and k is the conic constant, c is the curvature radius, and Cj is the coefficient of the monomial x^my" J (m + n +m + 3n / 2 + 1

In the present embodiment, m+n≤4, for instance, m=0, n=l, 2, 3 or 4

The second curve surface B is a rotational symmetric curve surface and may be described as a polynomial aspheric surface. In order to obtain a good uniformity of the light distribution, an axis of rotation of the second curve surface B is offset with respect to an optical axis Y of the light source. A contour of the second curve surface B is preferably defined by the following equations:

2 10

z = _/ ^Cr +∑¾

\ + \-(\ + k)c²r² i _r2 ₌ 2 ₊ 2 _ _

7 and ^J , wherein k is the conic constant, and c is the curvature radius. In the present embodiment, n=2 or 3.

An arc wall 1 as a portion of the lens base S is configured to protect and support the lens mainbody M. In the present embodiment, both fourth surface E and fifth surface F are plane surfaces and form certain angles with the optical axis Y.

There is a certain gap between a top end of the arc wall 1 and the fourth surface E for preventing light from scattering.

Fig. 2 is a bottom view of the lighting module according to Fig. 1. The positions of the lens mainbody M and the lens base S can be seen clearly in the figure. The lens base M defines a space with two side walls 2 and one arc wall 1 for surrounding the lens main- body M. Particularly, inner side surfaces D of the two side walls 2 is faced to the first curve surface A and an inner side surface of the arc wall 1 is faced to the third curve surface C. In the present preferred embodiment, the inner side surfaces D are total internal reflection surfaces. This design may improve the usage ratio of light on the projection wall, and form a uniform light distribution .

The lens L according to the present invention reduces generation of glare mainly through the designs of the third curve surface C, the inner side surfaces D, the fourth surface E and the fifth surface F, and improves the light uniformity and efficiency.

Fig. 3 is a top view of the lighting module according to Fig. 1. In the embodiment shown in the figure, the lighting module according to the present invention has a non-rotational symmetric outline but a traditionally rectangular bottom surface. This design is favorable for production and assembly in the precondition of maintaining the above merits.

Fig. 4 is a light intensity distribution view of the lighting module according to the present invention. It can be seen from the figure that light beam angles herein are 60°*20°. The light from the lighting module according to the present invention is distributed quite uniformly in a horizontal direction, but offset about 15-20 degrees in a vertical direction. The total energy is 897.311m, the efficiency is 0.89731, and the maximum light intensity is 1547.4 cd. Such offset in the vertical direction may enable the light emitted from the lighting module according to the present invention to be mainly concentrated in a predetermined range and not to diffuse undirectionally to the surrounding.

Fig. 5 is a light distribution view of the lighting module according to the present invention. It can be seen from the figure that the light emitted from the lighting module is uniformly distributed in the horizontal direction, and offset in the vertical direction .

Fig. 6 is a portion of X-orientation in the light distribution view according to Fig. 5. Corresponding to Fig. 5, the curve shown in the figure is uniformly symmetric in relation to the position of zero where a maximum value appears.

Fig. 7 is a portion of Y-direction in the light distribution view according to Fig. 5. Corresponding to Fig. 5, the curve shown in the figure has relatively big numerical values at a negative half axis with respect to the position of zero and relatively small numerical values at a positive half axis.

The results shown in Figs. 5-7 may clearly reflect one advantage of the lighting module according to the present invention, i.e. uniform light distribution and can produce the polarized light effect . Fig. 8 is an indoor wall washer according to the present invention. A plurality of lighting modules according to the present invention are mounted in the same direction in a mode of array in a lamp housing, while the other parts of the lamp body basically have the same configuration as common downlight means.

Fig. 9 is a unified glare rating distribution view of the indoor wall washer according to the present invention. It is shown in the present embodiment the unified glare rating distribution view of the indoor wall washer according to the present invention in a room having a length of 6m, a width of 6m and a height of 4m, and the projection wall is a wall of 6m * 6m. The unified glare rating UGR may be controlled below 10 by using the indoor wall washer according to the present invention.

₁

List of reference signs

1 arc wall

2 side wall

A first curve surface

B second curve surface

C third curve surface

D inner side surface of side wall 2

E fourth surface

F fifth surface

L lens

M lens mainbody

S lens base

Y optical axis of light source k conic constant

c curvature radius

Claims

1. A lens (L) , comprising a lens mainbody (M) and a lens base (S) supporting the lens mainbody (M) , wherein the lens mainbody (M) comprises an outer surface emitting light and an inner surface receiving light from a light source, and wherein the outer surface comprises a first curve surface (A) being asymmetric and having a first continuous curve shape; the inner surface comprises a second curve surface (B) being rotational symmetric and having a second continuous curve shape; the lens mainbody (M) further comprises a third curve surface (C) configured to at least partially reflect light from the second curve surface (B) to the first curve surface (A) .

2. The lens (L) according to claim 1, wherein the outer surface further comprises a fourth surface (E) adjoining the first curve surface (A) for reducing glare and improving light uniformity.

3. The lens (L) according to claim 1, wherein the inner surface further comprises a fifth surface (F) adjoining the second curve surface (B) for reducing glare and improving light uniformity.

4. The lens (L) according to claim 3, wherein the fifth surface (F) and the second curve surface (B) jointly define a space for accommodating the light source.

5. The lens (L) according to claim 1, wherein the first curve surface (A) is a 10^th-order polynomial surface added to a conic.

6. The lens (L) according to claim 5, wherein a contour of the first curve surface (A) may be defined by the following equations:

, wherein m+n≤10, and k is a conic constant, c is a curvature radius, Cj is a coefficient of

^2

m + n) +m + 3n / 2 + 1

the monomial X V J (

, and

7. The lens (L) according to claim 6, wherein m+n≤4.

8. The lens (L) according to claim 1, wherein the second curve surface (B)is a polynomial aspheric surface.

9. The lens (L) according to claim 8, wherein a rotational symmetry line of the second curve surface (B) is offset with respect to an optical axis (Y) of the light source.

10. The lens (L) according to claim 9, wherein a contour of the second curve surface (B) may be defined by the following equa-

10

^•2

Ι +

tions: ^vl· (\ + k)c²r² 2 . 2

=2

and x + y" , wherein k is a conic constant, and c is a curvature radius.

11. The lens (L) according to claim 10, wherein n=2 or 3.

12. The lens (L) according to claim 1, wherein the third curve surface (C) is a total internal reflection surface.

13. The lens (L) according to claim 1, wherein the lens base (S) has two side walls (2) and one arc wall (1) jointly defining a space for surrounding the lens mainbody (M) .

14. The lens (L) according to claim 13, wherein inner side surfaces (D) of the side walls (2) faced to the first curve surface (A) and an inner side surface of the arc wall (1) faced to the third curve surface (C) .

15. The lens (L) according to claim 14, wherein the inner side surfaces (D) of the side walls (2) are total internal reflection surfaces .

16. The lens (L) according to claim 2, wherein the fourth surface (E) is plane surfaces forming angles with an optical axis (Y) of the light source.

17 . The lens (L) according to claim 3, wherein the fifth surface

(F) is plane surfaces forming angles with an optical axis (Y) of the light source.

18. A lighting module having the lens (L) according to any one of claims 1-17.

19. The lighting module according to claim 18, wherein the lighting module is an LED module.

20. An indoor wall washer comprising an array formed by a plurality of the lighting modules according to claim 18 or 19.