WO2009147289A1

WO2009147289A1 - Apparatus for directing and illuminating light

Info

Publication number: WO2009147289A1
Application number: PCT/FI2009/050446
Authority: WO
Inventors: Toivo Vilmi
Original assignee: Valopaa Oy
Priority date: 2008-06-04
Filing date: 2009-05-27
Publication date: 2009-12-10
Also published as: FI20085548A0

Abstract

There is provided a reflector (300) for directing light, and a lighting module (400) for illuminating a desired area. The reflector comprises a plurality of consecutive sections (301, 302). Predetermined acute angles (318) of peripheral lateral surfaces (308) of the sections (301, 302) with respect to an optical central axis (319) of the reflector (300) decrease as aperture areas at second ends (312) increase in the consecutive sections (301, 302).

Description

Apparatus for Directing and Illuminating Light

Field

The invention relates generally to illumination apparatuses, and more particularly to a reflector and a modular reflector structure for directing light, and a lighting module and a modular lighting structure for illuminating an area.

Background

It is important to obtain good lighting in populated areas that are dark or otherwise in need of more light. Often the sun as a light provider is not enough and therefore lamps are needed to provide additional lighting. Environments where lamps are needed can be found for example indoors, in outdoor sport facilities and streets. A lamp that provides additional lighting may be placed in various ways such as on a table, on a floor, hanging from a roof or a ceiling or on a street pole. Providing additional lighting to a desired area by means of lamps is known per se. However, in current lighting systems light is emitted from a lamp to a wide area including spots where light from the specific lamp may not be needed. This may be the case for example in street lighting where a plurality of separated lamps provides lighting to a street. It may happen that light from one lamp may unintentionally spread to the coverage area of another lamp, thereby leading to waste of the illumination resources and unnecessary additional costs.

The reason for the wide spreading of the light lies in the shape of the beam of the light. Nowadays, light emitting diodes (LED) are applied to lighting devices for emitting light. Typically, the beam of light 102 to 106 with LED lighting solutions follows the Gaussian curve as shown in Figure 1 in a case where a plurality of street lamps (not shown) illuminate the street. The light beams 100 to 106 have wide side lobes on a ground 107, which wastes illuminating resources. Further, another disadvantage of the Gaussian curve - shaped beams 102 to 104 is that the light focuses at a specific spot 110 to 116, which is located directly under the emitting light. In other words, the Gaussian shaped beam produces an undesired bright light at the spots 110 to 116 directly under the street lamps and the luminance level drops rapidly but continuously on the sides wasting resources on the wide side lobes. An overall luminance level 108 shows that the brightness on the ground 107 is uneven. Thus, solutions that provide uniform luminance exactly to the desired area without wasting the illumination resources are needed.

Brief description of the invention An object of the invention is to provide a reflector, a lighting module, a modular reflector structure and a modular lighting structure for illuminating a desired area.

According to an aspect of the invention, there is provided an apparatus as specified in claims 1 , 7, 14 and 15. Embodiments of the invention are defined in the dependent claims.

List of drawings

In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which

Figure 1 presents a prior art luminance level on a ground; Figure 2 shows a luminance level on a ground, according to an embodiment;

Figure 3A shows a reflector for directing light, according to an embodiment;

Figure 3B illustrates an additional section of the reflector; Figure 4A illustrates a lighting module according to an embodiment;

Figure 4B illustrates a port pattern produced by the lighting module, according to an embodiment;

Figure 5 presents a prism for further directing light, according to an embodiment; Figure 6 presents a modular reflector structure according to an embodiment; and

Figure 7 illustrates a modular lighting structure according to an embodiment.

Description of embodiments The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single em- bodiment. Single features of different embodiments may also be combined to provide other embodiments.

As shown in Figure 1 , a typical beam of light in LED lighting solutions follows the Gaussian curve, thereby leading to poor performance and an uneven lighting on the ground. According to an embodiment of the invention, the shape of the beam of light is improved to produce an even lighting on the ground without wasting lighting resources. This is shown in Figure 2, wherein four beams 200 to 206 of light illuminate the ground 107. For example, when two street lamps producing the light beams 200 and 202 are appropriately placed apart, an overall luminance level 208 on the ground 107 may be even. However, the distance between the street lamps producing the light beams 202 and 204 may be too small, thereby leading to an increase in the overall luminance level 208. On the other hand, if the distance between the light beams is too large, there may exist a decrease in the overall luminance level 208, as shown with light beams 204 and 206.

The shape of the light beam is significantly different from the typical Gaussian curve shaped beam. In an embodiment of the invention, the light beam may comprise a flat portion in the horizontal middle part of the beam, and the luminance level on the sides of the beam may not decrease as dra- matically as in the Gaussian curve beam. Further, there may be no side lobes to waste the lighting resources of a lighting system. This may lead to an even lighting without a bright spot directly under the lamp producing the light beam. Accordingly, the beam of the light may be called a gate pattern since it may produce a light that is strictly limited to a certain area. In an embodiment, the shape of the light beam is obtained with a reflector that may be used for directing light to a desired area. The reflector is shown in Figure 3A with a reference number 300. As shown, the reflector 300 may comprise a first section 301 comprising a peripheral lateral surface, a first end and a second end with an aperture. The first end of the first section 301 may or may not comprise an aperture. That is, the first end of the first section 301 may be closed or it may comprise an aperture through which light may enter the reflector 300.

Further, the reflector 300 may comprise at least one additional section 302A to 302D. Each of the additional sections 302A to 302D may com- prise a peripheral lateral surface 308 at a predetermined acute angle with respect to an optical central axis 319 of the reflector 300, a first end 310 with an aperture, and a second end 312 with an aperture, wherein the aperture area at the second end 312 is larger than the aperture area at the first end 310, as shown in Figure 3B. Thus, light shown with a reference number 320, when fed from one of the apertures, may pass through the additional section 302 and exit from the other aperture.

The reference number 302 in Figure 3B denotes any of the additional sections 302A - 302D in Figure 3A. However, it is to be noted that even though Figure 3B illustrates the structure of the additional section 302, the first section 301 may be of a similar structure, except that no aperture at the first end 310 is required. For this reason the reference numbers 308 and 312 apply to the first section 301 as well. Further, from now on the term "section" without a prefix "first" or "additional" comprises both the additional section 302 and the first section 301.

In an embodiment, the material of the section 301 , 302 is any light reflecting material such as aluminum, steel or plastic. Consequently, the material of the reflector 300 comprising the sections 301 , 302 may be any material with light reflecting characteristics.

In Figure 3A, the optical central axis 319 of the reflector 300 may be a virtual longitudinal axis of the reflector 300 virtually passing through the aper- tures. Further, the length of the peripheral lateral surface 308 of a section 301 , 302 is not limited. The shape of the sections 301 , 302 is depicted in Figure 3B to be a circular cone which is cut at both ends 310 and 312 to form apertures. Accordingly, in an embodiment, the section 301 , 302 is a conical section. The invention is, however, not limited to the conical section but the shape of the section 301 , 302 may vary from that. That is, the shape of the aperture may vary from a circle such that the shape may be for example an oval, a quadrangle or a triangle.

In Figures 3A and 3B, the sections 301 , 302A to 302D may be consecutive such that the sections 301 , 302A to 302D are in increasing order of the aperture areas at the second ends 312 of the sections 301 , 302A to 302D, and the aperture at the second end 312 of a section 301 , 302A to 302D is consecutive to the aperture at the first end 310 of a next section 302A to 302D. For example, the aperture at the second end 312 of the section 302C is consecutive to the aperture at the first end 310 of the section 302D. That is, the sections 301 , 302A to 302D may be consecutive such that in each section 301 , 302A to 302D, the first end 310 is on the same side with respect to the second end 312.

In an embodiment, referring to Figures 3A and 3B, predetermined acute angles 318 of the peripheral lateral surfaces 308 with respect to the opti- cal central axis 319 of the reflector 300 decrease as the aperture areas at the second end 312 increase in the consecutive sections 301 , 302. For example, an acute angle 318A is larger than an acute angle 318B with respect to the optical central axis 319 of the reflector 300.

In an embodiment, referring to Figures 3A and 3B, the sections 301 , 302A to 302D may be consecutive such that the peripheral lateral surface 308 of a section 302A to 302D is connected to the peripheral lateral surface 308 of a previous section 301 , 302A to 302D. In other words, the peripheral lateral surface 308 of additional section 302A is connected to the peripheral lateral surface 308 of the additional sections 302B. In other words, a peripheral lateral surface 314 of the reflector 300 may grow in length, as more additional sections 302A to 302D become consecutive since the peripheral lateral surface 314 of the reflector 300 comprises all the peripheral lateral surfaces 308 of the sections 301 , 302.

In an embodiment, referring to Figures 3A and 3B, the sections 301 , 302A to 302D may be consecutive such that the shape of the aperture at the second end 312 of a section 301 , 302A to 302D is identical to the shape of the aperture at the first end 310 of a next section 302A to 302D. For example, the shape of the aperture at the second end 312 of the section 302A is identical to the shape of the aperture at the first end 310 of the section 302B. Thus, the joints between the sections 301 , 302A to 302D may be impervious thus preventing light from escaping from between the sections 301 , 302A to 302D.

After placing the sections 301 , 302A to 302D consecutively, the reflector 300 may finally comprise the peripheral lateral surface 314, a first end 316, and a second end 317 with an aperture. Further, since the first section 301 may or may not comprise an aperture at the first end of the first section 301 , the reflector 300 may or may not comprise an aperture at the first end 316 of the reflector 300. The first end 316 of the reflector 300 may, thus, be closed or it may comprise an aperture. The first end 316 of the reflector 300 may be closed with an impervious light reflecting material. The first end 316 of the re- flector 300 may comprise an aperture through which light may enter the reflector 300 or which is used for providing power for the at least one light source. In Figure 3B, the second end 312 of the section 302 with the largest aperture at the second end 312 may be the second end 317 of the reflector

300 in Figure 3A. Further, the first end of the first section 301 may be the first end 316 of the reflector 300. The reflector 300 may be a molded block of a reflecting material.

The molded block of material may comprise sections 301 , 302 consecutive to each other. Alternatively, the reflector 300 may be assembled, for exampled, by placing sections 301 , 302 of a light reflecting material consecutive to each other. The reflector 300 may be applied to a lighting module 400 as shown in Figure 4A for illuminating a desired area. The lighting module may, thus, comprise the reflector 300. The lighting module 400 may further comprise at least one light source 406 that may emit light.

The lighting module 400 may comprise only one light source 406 or it may contain several light sources 406. The at least one light source 406 may emit light from a single point or it may emit light from a surface with a predetermined surface area, as is the case in Figure 4A. In an embodiment, the at least one light source comprises a light emitting diode (LED). The at least one light source 406 may further comprise a base to which the at least one light source 406 is attached or mounted. If the first end 316 of the reflector 300 comprises an aperture, the base may close the aperture. If the at least one light source 406 is a LED, the base may be used for attaching the LED via terminal pins of the LED and for feeding current to the LED.

In an embodiment, the at least one light source 406 is placed such that light emitted from the at least one light source 406 travels inside the reflector 300. The light traveling inside the reflector may bounce from the inner surface of the peripheral lateral surface 314 of the reflector 300 and exit from an aperture.

In an embodiment, the at least one light source 406 is placed at the first end of the first section 301. As mentioned, the first end of the first section

301 may or may not comprise an aperture. Thus, the light source may be attached to the closed first end of the first section 301 or it may be placed at the aperture of the first end of the first section 301 with or without an impervious joint with the aperture edges. The at least one light source 406 may emit light towards the aperture at the second end 317 of the reflector and the inner sur- face of the peripheral lateral surface 314 of the reflector 300 may further direct the light towards the aperture at the second end 317 of the reflector 300.

Figure 4A shows how the sections 301 , 302A to 302D may reflect and direct light emitted from the at least one light source 406. Light rays 404A to 404G travel inside the reflector 300 after being emitted from the at least one light source 406. It is shown that sections 301 , 302A to 302D direct the light rays 404A to 404G towards the aperture at the second end 317 of the reflector 300. Thus, the light rays 404A to 404G exit the reflector 300 through the aperture at the second end 317 of the reflector 300. The light emitted from the at least one light source 406 may bounce differently from the same section 301 , 302A to 302D, depending on the impact location of the light rays 404A-404G with respect to the section 301 , 302A to 302D. In this manner, the reflector 300 may generate a port pattern of the light beam, thus enabling accurate illumination of a certain area without resource-wasting side lobes. For example, in a case where the lighting module 400 is applied, for example to a street lamp, the reflector 300 of the lighting module 400 may be designed such that the lighting module 400 generates a port pattern with a light beam 410 illuminating an area on the ground 107 that is limited in each direction by N degrees with respect to the optical central axis 319 of the reflec- tor 300 as shown in Figure 4B.

Further, the lighting module 400 may comprise a lens 402 that may shape the beam of light exiting the reflector 300. The lens 402 may be convex or concave, thus either narrowing or spreading the light beam, respectively. In Figure 4A, the lens 402 is a convex lens, thereby directing the impacted light rays 404A to 404G towards the focus of the lens 402. However, the lens 402 may be an asymmetric lens. That is, it may direct the light rays 404A to 404G differently, depending on the impact location of the light rays 404A to 404G on the lens 402.

The lens 402 may be placed such that the lens 402 may shape the beam of light traveling through the aperture with the largest area. In an embodiment, the lens 402 is placed a predetermined distance apart from the reflector 300, as shown in Figure 4A. The lens 402 may alternatively be attached to the reflector 300. For example, the lens 402 may be attached to the aperture at the second end 317 of the reflector 300. In an embodiment, the lens 402 may be parallel to the direction of the aperture with the largest aperture area. In an embodiment, the lens 402 may be inclined with respect to the direction of the aperture with the largest aperture area, i.e., the aperture at the second end 317 of the reflector 300.

In an embodiment, the lens 402 may be wider than the aperture at the second end 317 of the reflector 300. The lens 402 may further direct the light rays 404A to 404G, which exit the reflector 300 at such an angle that they would not illuminate the desired area, towards a desired area. For example in Figure 4A, the lens 402 may direct the light ray 404G towards the desired illumination area after the light ray 404G has exited the reflector 300 at such an angle that without the lens 402 it would illuminate an undesired area. The lighting module 400 may further comprise a prism that may direct light to the desired area, wherein the prism may be integrated into the lens 402. Figure 5 shows that the prism 502 may be applied to directing light rays 504A to 504B towards the desired target. The prism 502 may be integrated into the lens 402 or it may be used as a separate directing means. Thus, the reflector 300, the lens 402 and the prism 502 may together form a structure that is used for directing the light to a desired area.

In an embodiment, the reflector 300 may be a reflector of a street lamp. In an embodiment, the lighting module 400 may be a lighting module of a street lamp. The street lamp may be used to illuminate streets to provide better light coverage to the street users such as pedestrians, cyclists and drivers. The street lamp may be placed on a high post, as is the case with typical street lamps.

In Figure 6, a modular reflector structure 600 is shown. The modular reflector structure 600 may be used for directing light and it may comprise a base 602 and a plurality of reflectors 300A to 300C attached to the base 602.

The base 602 may be, for example, a solid block with the reflectors 300A to 300C molded inside the block, as shown in Figure 6. Alternatively, the reflectors 300A to 300C may be engraved in the base 602. That is, the engraved surface may comprise a plurality of sections 301 , 302. The base 602 is not limited to the form shown in Figure 6. It may be of any form that allows the attachment, molding or engraving of the reflectors 300 into the base 602.

The modular reflector structure 600 may comprise a plurality of reflectors 300 and they can be in one row or they may be in a plurality of rows. For example, the modular reflector structure 600 may comprise three rows, each having three reflectors 300, thus comprising altogether nine reflectors 300. It is not required that all of the reflectors 300 are used for directing light. That is, for reasons of simplicity in manufacturing, the modular reflector structure 600 may comprise a certain number of reflectors 300 even though some of the reflectors 300 may not be used for directing light.

Further, not all of the reflectors 300 need to be identical. That is, each of the reflectors 300 in Figure 6 may have a unique predetermined shape generated by, for example, placing the plurality of sections 301 , 302 shown in Figures 3A and 3B consecutively or by engraving the plurality of sections 301 , 302 into the base 602, wherein each of the sections 301 , 302 may be at a unique predetermined acute angle with respect to the optical central axis 319 of the reflector 300. Similarly, each of the sections 301 , 302 may have a unique predetermined length of the peripheral lateral surface 308. Thus, each of the reflectors 300 may have, for example, a different length and shape of the peripheral lateral surface 314 and a different area of the aperture at the second end 317 of the reflector 300. Figure 7 illustrates a modular lighting structure 700 according to an embodiment of the invention. The modular lighting structure 700 may be applied for illuminating a desired area. It may comprise a base 702 and a plurality of lighting modules 400A to 400C attached to the base 702. Each of the modules 400A to 400C may comprise the at least one light source 406A to 406C and the reflector 300A to 300C.

The shape of the base 702 is not limited to the one shown in Figure 7. It may be, for example, a block similar to that shown with the reference number 602 in Figure 6. In the case of LEDs, the base 702 may be, for example, a ceramic structure to which the at least one light source 406 for each lighting module 400 is attached.

Further, each of the lighting modules 400A to 400C may have a predetermined number of light sources 406 and a predetermined shape of the reflector 300. That is, each of the reflectors 300 in Figure 7 may have a unique predetermined shape generated by, for example, placing the plurality of sec- tions 301 , 302 shown in Figure 3A and 3B consecutively or by engraving the plurality of sections 301 , 302 into the base 602, wherein each of the sections 301 , 302 may be at a unique predetermined acute angle with respect to the optical central axis 319 of the reflector 300. Similarly, each of the sections 301 , 302 may have unique predetermined length of the peripheral later surface 308. Thus, each of the reflectors 300 may have, for example, a different length and shape of the peripheral lateral surface 314 and a different area of the aperture at the second end 317 of the reflector 300.

Moreover, each of the lighting modules 400A to 400C of the modular lighting structure 700 may be individually directed. For example, the lighting modules 400A to 400C may be directed in different directions as shown in Figure 7. Consequently, the modular lighting structure 700 may provide illumination to a wide area.

In an embodiment, the modular lighting structure 700 may further comprise a lens 704 that may shape the beam of light emitted from the plurality of lighting modules 400A to 400C. The lens 704 may be one entity providing light beam shaping to all of the lighting modules 400A to 400C or each of the lighting modules 400A to 400C may have an own individually shaped lens of their own.

The lens 704 may comprise a plurality of individually shaped por- tions 706A to 706C that may shape the beam of light, wherein each of the individually shaped portions 706A to 706C may shape the beam of light emitted from a certain lighting module 400. The certain lighting module 400 may be, for example, the lighting module 400 closest to the individually shaped portion 706A to 706C of the lens 704. The individually shaped portion 706A may be a convex lens, whereas the individually shaped portion 706C may be a concave lens. Further, any of the individually shaped portions 706A to 706C may be an asymmetrical lens. The shaping of the individually shaped portions 706A to 706C of the lens 704 may be chosen individually according to the illumination needs for each lighting module 400A to 400C. The lens 704 may further comprise safety regions 708A, 708B between each pair of individually shaped portions 706A to 706C of the lens 704. The purpose of the safety regions 708A, 708B may be to separate a pair of individually shaped portions 706A to 706C, wherein the safety region 708A, 708B does not affect the beam of light emitted from any of the lighting modules 400A to 400C.

The modular lighting structure 700 may further comprise a plurality of individually shaped prisms 710 that may further direct light emitted from the lighting modules 400A to 400C to the desired area, wherein each of the individually shaped prisms 710 direct light emitted from a certain lighting module 400. The certain lighting module 400 may be, for example, the lighting module 400 closest to the individually shaped prism 710. Further, the individually shaped prisms 710 may be integrated into a corresponding individually shaped portion 706A to 706C of the lens 704. The shaping of the individually shaped prisms 710 of the lens 704 may be chosen individually according to the illumination needs for each lighting module 400A to 400C. Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined in various ways with other embodiments.

Claims

1 . A reflector for directing light, comprising a first section (301 ) comprising a peripheral lateral surface, a first end, and a second end with an aperture, c h a r a c t e r i z e d i n that the reflector (300) further comprises at least one additional section (302), wherein each of the additional sections (302) comprises a peripheral lateral surface (308) at a predetermined acute angle (318) with respect to an optical central axis (319) of the reflector (300), a first end (310) with an aperture, and a second end (312) with an aperture, wherein the aperture area at the second end (312) is larger than the aperture area at the first end (310), the sections (301 , 302) are consecutive such that the sections (301 ,

302) are in increasing order of the aperture areas at the second ends (312) of the sections (301 , 302), and the aperture at the second end (312) of a section (301 , 302) is consecutive to the aperture at the first end (301 ) of a next section

(302), and the predetermined acute angles (318) of the peripheral lateral surfaces (308) with respect to the optical central axis (319) of the reflector (300) are decreasing as the aperture areas at the second ends (312) increase in the consecutive sections (301 , 302).

2. The reflector of claim 1 , wherein the sections (301 , 302) are consecutive such that the peripheral lateral surface (308) of a section (302) is connected to the peripheral lateral surface (308) of a previous section (301 , 302).

3. The reflector of any of the preceding claims, wherein the sections (301 , 302) are consecutive such that the shape of the aperture at the second end (312) of a section (301 , 302) is identical to the shape of the aperture at the first end (310) of a next section (302).

4. The reflector of any of the preceding claims, wherein the section (301 , 302) is a conical section.

5. The reflector of any of the preceding claims, wherein the reflector

(300) is a reflector of a street lamp.

6. The reflector of any of the preceding claims, wherein the reflector (300) is a molded block of a reflecting material.

7. A lighting module for illuminating a desired area, comprising: at least one light source (406) configured to emit light, c h a r a c t e r i z e d i n that the lighting module further comprises: a reflector (300) of any of claims 1 to 6; and the at least one light source (406) is placed such that light emitted from the at least one light source (406) is configured to travel inside the reflector (300).

8. The lighting module of claim 7, wherein the at least one light source (406) is placed at the first end of the first section (301 ).

9. The lighting module of claims 7 to 8, further comprising: a lens (402) configured to shape a beam of light exiting the reflector (300).

10. The lighting module of claim 9, wherein the lens (402) is asymmetric.

1 1 . The lighting module of any of the preceding claims 9 to 10, further comprising: a prism (502) configured to direct light to a desired area, wherein the prism (502) is integrated into the lens (402).

12. The lighting module of any of the preceding claims 7 to 1 1 , wherein the lighting module (400) is a lighting module of a street lamp.

13. The lighting module of any of the preceding claims 7 to 12, wherein the at least one light source comprises a light emitting diode.

14. A modular reflector structure for directing light, comprising a base (602), c h a r a c t e r i z e d i n that the modular reflector structure (600) comprises a plurality of reflectors (300) of any of claims 1 to 6 attached to the base (602).

15. A modular lighting structure for illuminating a desired area, com- prising a base (702), c h a r a c t e r i z e d i n that the modular lighting structure (700) comprises a plurality of lighting modules (400) of any of claims 7 to 13 attached to the base (702).

16. The modular lighting structure of claim 15, wherein each of the lighting modules (400) has a predetermined number of light sources (406) and a predetermined shape of the reflector (300).

17. The modular lighting structure of any of the preceding claims 15 to 16, further comprising a lens (704) configured to shape a beam of light emit- ted from the plurality of lighting modules (400).

18. The modular lighting structure of claim 17, wherein the lens (704) comprises: a plurality of individually shaped portions (706) configured to shape the beam of light, wherein each of the individually shaped portions (706) shape the beam of light emitted from a certain lighting module (400); and a safety region (708) between each pair of individually shaped portions (706) of the lens (704) configured to separate the pair of individually shaped portions (706), wherein the safety region (708) does not affect the beam of light emitted from any of the lighting modules (400).

19. The modular lighting structure of any of the preceding claims 17 to 18, further comprising a plurality of individually shaped prisms (710) configured to further direct light from the lighting modules (400) to the desired area, wherein each of the individually shaped prisms (710) direct light emitted from a certain lighting module (400) and is integrated into a corresponding individually shaped portion (706) of the lens (704).

20. The modular lighting structure of any of the preceding claims 15 to 19, wherein each of the lighting modules (400) is individually directed.