AU2014224143A1

AU2014224143A1 - Led road lamp

Info

Publication number: AU2014224143A1
Application number: AU2014224143A
Authority: AU
Inventors: Huan LI
Original assignee: GE Lighting Solutions LLC
Current assignee: Current Lighting Solutions LLC
Priority date: 2013-09-18
Filing date: 2014-09-15
Publication date: 2015-04-02
Also published as: CN104456274A; KR20150032504A; CN104456274B

Abstract

The present invention discloses a LED road lamp including LED light sources and a reflector assembly. The reflector assembly includes a pair of back-to-back curved surface reflectors arranged symmetrically. Each of the curved surface reflectors is designed as a continuous parabolic curved surface along a direction parallel to the road surface for reflecting light emitted from the LED light sources, so that the light is irradiated to a predetermined area along the direction parallel to the road surface after reflection. The LED road lamp of the present invention may reflect once the majority of the light emitted by the LED light sources within the predetermined area of the road surface, improving the system's luminous efficiency in one aspect, and meeting the requirement of the actual road for light distribution in another aspect. CN (

Description

LED ROAD LAMP [0001] This application claims priority from Chinese Patent Application No. 201310429051.1 filed on 18 September 2013, the contents of which are to be taken as incorporated herein by this reference. BACKGROUND [0002] The present invention generally relates to a road lamp, and more particularly to a road lamp using a LED (light-emitting diode) as a light source. [0003] A LED, as a new light source, has become the development trend of the next generation light source for many advantages such as its long life, high luminous efficiency, multi-color and function of directional light irradiation in light distribution once, as well as being workable under safe voltage. But the conventional LED road lamps have a similar light distribution curve as conventional light sources which is distributed normally around a wide-angle circumference and, the illuminance of light spot decreases so rapidly outward from the central region that there are problems like small irradiated area and low remote illuminance which are difficult to meet the irradiation requirements of road surface in light distribution design aspects. In one aspect, irradiation distance of the light source along a direction parallel to the road surface is short, and a dark zone without illumination is formed on the road surface between light spots of adjacent road lamps. In another aspect, another part of light is not irradiated on the road surface, but irradiated longitudinally to make a waste on illuminating the roadside. At the same time, illuminance uniformity of the conventional LED road lamps is not perfect, resulting in wasting energy and bringing great inconvenience to night driving which causes the security risks. [0004] In order to solve the above problems, a conventional method is to design an optical lens for the light distribution design of LED light source. The light emitting direction of the LED light source is changed through the lens, so that the propagation direction is shifted to eliminate shadows between adjacent light spots to form a rectangular light strip on the road surface, for improving the lighting efficiency and ensuring the security purpose of driving at night. [0005] However, there are many disadvantages in use of optical lenses for light distribution design of LED light sources: firstly, the LED light sources with different characteristics require optical lens with different diopter, resulting in no good interchangeability between the lens and the LED light sources; secondly, if we use glass as lens materials, it will cause processing complexity and high cost, while the use of PC resin to make a lens will cause life issues, general lifetime less than one year. If we use a conventional lamp shade directly, it may not match the integrated package type LED light source and cause many drawbacks; thirdly, the energy of light sources is not irradiated totally within the road surface's effective area, irradiation distance along the direction parallel to the road surface is shorter, and the illuminance uniformity is not ideal. [0006] Accordingly, it is desirable to develop a new LED road lamp to solve the above problems. [0007] The discussion of the background to the invention included herein including reference to documents, acts, materials, devices, articles and the like is included to explain the context of the present invention. This is not to be taken as an admission or a suggestion that any of the material referred to was published, known or part of the common general knowledge in Australia or in any other country as at the priority date of any of the claims. BRIEF DESCRIPTION [0008] The present invention is now summarized into one or more aspects in order to facilitate a basic understanding, wherein the summarization does not equal to an extensibility overview, and not intend to identify certain elements of the present invention, yet not to draw the scope. In contrast, the main purpose of the summarization is to present some concepts in a simplified form before more detailed descriptions hereinafter.

[0009] In one aspect of the present invention, a LED road lamp is provided. The LED road lamp comprises LED light sources and a reflector assembly. The reflector assembly comprises a pair of back-to-back curved surface reflectors arranged symmetrically. Each of the curved surface reflectors is designed as a continuous parabolic curved surface along a direction parallel to the road surface for reflecting light emitted from the LED light sources, so that the light is irradiated to a predetermined area along the direction parallel to the road surface after reflection. [0010] In some embodiments, each of the curved surface reflectors is designed as a continuous left-right non-symmetrical arc-shape along a direction vertical to the road surface, and the LED light source located in each of the curved surface reflectors is installed on one side of the arc-shape back to the road surface to reflect light through one side of the arc-shape facing the road surface within a predetermined area along the direction vertical to the road surface. [0011] In another aspect of the present invention, a LED road lamp is provided. The LED road lamp comprises a backboard mounted with LED light sources and a reflector module for light reflection. The reflector module comprises a plurality of reflector assemblies. Each reflector assembly comprises a pair of back-to back curved surface reflectors arranged symmetrically on two sides of the backboard, and each curved surface reflector is designed as a continuous parabolic curved surface along a direction parallel to the road surface for reflecting light emitted from the LED light sources, so that the light is irradiated to a predetermined area along the direction parallel to the road surface after reflection. [0012] Compared to the prior arts, the LED road lamp of the present invention provides a pair of back-to-back curved surface reflectors arranged symmetrically, and each of the curved surface reflectors is designed as a continuous parabolic curved surface along the direction parallel to the road surface for reflecting light emitted from the LED light sources, so that the light may be irradiated to the predetermined area along the direction parallel to the road surface after reflection. By designing the reflectors as a continuous parabolic curved surface, most of the light from the LED light sources may be irradiated to the predetermined area of the road surface after once reflection in addition to a portion of the light irradiated directly to the road surface, the loss of light can be avoided, the system's luminous efficiency can be improved greatly, and the irradiation distance of light can be designed very long to meet the requirements of the actual roads for light distribution. In some designs, each of the curved surface reflectors is designed as a continuous left-right non-symmetrical arc-shape along a direction vertical to the road surface, and the LED light source located in each of the curved surface reflectors is installed on the side of the arc-shape back to the road surface to reflect light through the side of the arc-shape facing the road surface within the predetermined area along the direction vertical to the road surface. Therefore, most of the light may be irradiated to the road surface and not be irradiated to the roadside area. Furthermore, the LED road lamp of the present invention may adopt modular design, which one or more reflector assemblies can be freely mounted thereon or be removed therefrom so as to meet the light distribution requirements of the different light intensity, and is very convenient. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The present disclosure will become more apparent in light of the following detailed description in conjunction with the accompanying drawings in which: [0014] FIG. 1 is a schematic view of a LED road lamp used for a road surface according to a preferred embodiment of the present invention. [0015] FIG. 2 is a schematic perspective view of a reflector module on one side of the LED road lamp according to a preferred embodiment of the present invention. [0016] FIG. 3 is a schematic perspective view of FIG. 2 in another direction. [0017] FIG. 4 is a schematic side view of the reflector module of FIG. 2. [0018] FIG. 5 is a top view of FIG. 2. [0019] FIG. 6 is a side view of FIG. 2.

[0020] FIG. 7 is a light distribution curve graph of the LED road lamp used for a specific road surface according to the present invention. [0021] FIG. 8 is a schematic top view of a reflector module on one side of a LED road lamp according to another preferred embodiment of the present invention. [0022] FIG. 9 is a schematic view of a backboard corresponding to reflector assemblies on one side of the LED road lamp according to a preferred embodiment of the present invention. [0023] FIG. 10 is a schematic view of a LED road lamp according to another preferred embodiment of the present invention. DETAILED DESCRIPTION [0024] The specific embodiments of the present invention will be described below. It is noted that, in these embodiments' detailed description, for purposes of brevity of description, the present specification is impossible to describe all features of an actual embodiment in detail. It should be appreciated that, in the practical implementation process of any one embodiment, as in any engineering project or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business related constraints, which may vary from one embodiment to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, which should not be understood that the disclosure is not sufficient. [0025] Unless otherwise defined, technical and scientific terms used in the specification and claims have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. The terms "first", "second" and the like, as used herein don't denote any order, quantity or importance, but rather are used to distinguish different components. Also, the terms "a", "an" and similar terms herein don't mean any quantitative restriction, but rather are used to denote at least one. The use of "including," "comprising" or "having" and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. "Connect", "link" and other similar terms are not limited to physical or mechanical connections, but rather may include electrical connection either directly or indirectly. [0026] As shown in FIG. 1, a schematic view of a LED road lamp 10 used for a road surface 20 according to a preferred embodiment of the present invention is shown. For convenience of explanation, only four LED road lamps 10 are illustrated in FIG. 1, two of which are located on one side 21 of the road surface 20 and another two are located on the other side 22 of the road surface 20. The actual number of road lamps can be changed if required. The LED road lamp 10 comprises a lamp pole 11, a backboard 12 and reflector modules 13 arranged symmetrically on two sides of the backboard 12. [0027] The lamp pole 11 is used to support the road lamp's main body, and is usually a straight long pole, but it can also be designed to a structure with the top slightly tilted towards one side of the road surface or other structures corresponding to a specific road condition. The backboard 12 is used to install LED light sources and other control circuit. The LED road lamp 10 may also include other elements such as heat sink and etc. Since the lamp pole 11, the control circuit on the backboard 12, the heat sink and other elements are not the focus of the present invention, they are not described in detail herein. As an example, in this embodiment, the backboard 12 includes a pair of backboards for respectively installing the corresponding reflector modules 13 arranged symmetrically. In other embodiments, the pair of backboards 12 may also be integrated into a single backboard. The reflector modules 13 arranged symmetrically are respectively installed on two sides of the single backboard. [0028] When installing the road lamp 10 of the present embodiment, two wings of the reflector modules 13 are required to be set in a direction parallel to the road surface 20 (shown in FIG. 1), so that the light reflected by the reflector modules 13 may irradiate respectively along the road direction on two sides of the lamp pole 11. Since the structures of the reflector modules 13 arranged symmetrically on two sides are identical, the reflector module 13 on only one side will be described in the following paragraphs. [0029] As shown in Fig. 2 and FIG. 3, schematic perspective views of the reflector module 13 of a preferred embodiment on one side in two different directions are shown. In this embodiment, the reflector module 13 on one side comprises one half part of three side by side reflector assemblies 131 arranged in parallel, and on the other side is designed as a symmetrical structure which includes the other half part of three side by side reflector assemblies 131 arranged parallel. Only one half part will be described in detail herein and the other half part will be not repeated any longer. In other embodiments, the amount of the reflector assemblies 131 may be adjusted according to actual requirements, such as one, two or more than three. Such the design allows the reflecting system of the road lamp to achieve a modular configuration, adding or reducing the number of the corresponding reflector assemblies 131 to form different modular reflector modules 13. The reflector assemblies 131 on the reflector module 13 may be disassembled or assembled freely, for example achieved by snap structures, which is very convenient and may adapt to the lighting requirements in different locations. For instance, only one reflector assembly 131 or the reflector assemblies 131 on only one side is needed to meet the requirements in a low brightness demand occasion, which is cost saving. Moreover, when a plurality of reflector assemblies 131 may be needed in a high brightness demand occasion, the plurality of reflector assemblies 131 can be side by side assembled in parallel to the reflector module 13 with the desired light distribution requirement, which is very convenient. [0030] To improve the system's luminous efficiency, each reflector assembly 131 is designed to a pair of back-to-back curved surface reflectors arranged symmetrically with the inner wall 1311 set as a reflective surface, which in the present embodiment is designed to fully specular reflection, for example, by vacuum aluminizing technology to achieve reflective design with high reflectivity and low prices. In other embodiments, other mirror material surface treatment processes can also be used, such as electroplating, polishing or spraying reflective media film, etc. The LED light sources 121 are set on the backboard 12 and are located within each reflector assembly 131. A part of light emitted by the LED light sources 121 is irradiated directly to the road surface 20, and another part is irradiated to the road surface 20 after reflected by the reflective surface of the inner wall 1311. The reflective surface set on the inner wall 1311 of the present invention may reflect the light emitted by the LED light sources 121 to a predetermined area on one side of the road surface 20, that is, the light distribution curve is located within the predetermined area. [0031] Continuing to refer to FIG. 4, a schematic side view of the curved surface reflector on one side of one reflector assembly 131 along a direction parallel to the road surface 20 is shown. To achieve the above set requirements of the reflective surface of the inner wall 1311, the inner wall 1311 of the reflector assembly 131 is designed to a continuous off-axis parabolic curved surface shape along the direction parallel to the road surface 20, which is calculated in accordance with the law of reflection of light. In other words, along the direction parallel to the road surface 20, the irradiation distance d of the light irradiated and reflected from the LED light sources 121 within the predetermined area of the road surface 20 is determined according to the specifically designed off-axis parabolic curved surface shape, for instance, the irradiation distance d may be set as three, five or more times higher than the height of the lamp pole 11 to meet the light distribution requirements of a practical road. In unrestricted embodiments, the off-axis parabolic curved surface of the inner wall 1311 may be formed on the basis of a plurality of contour lines calculated from a curve fitting algorithm which is the prior art and is not specifically described herein. Since the irradiation distance d can be used to design a corresponding off-axis parabolic curved surface by the law of reflection of light in accordance with practical requirements, the flexibility of light distribution may be greatly improved. Besides, the inner wall 1311 of the reflector assembly 131 is designed to a continuous off-axis parabolic curved surface, so most of light from the LED light sources 121 may be directly irradiated to a predetermined area of the road surface 20 after once reflection except a part of light being irradiated directly onto the road surface 20, which avoids the loss of light, and greatly improves the system's luminous efficiency.

[0032] Referring to FIG. 5 and FIG. 6, FIG. 5 and FIG. 6 are respectively a top view of the reflector module 13 on one side and a schematic side view along a direction vertical to the road surface 20. In this embodiment, the inner wall 1311 of the curved surface reflector on one side of each reflector assembly 131 has a continuous left-right non-symmetrical arc-shape design along the direction vertical to the road surface 20, and the LED light source 121 located within each reflector assembly 131 are installed on one side of the arc-shape back to the road surface, so that the light may be reflected within a predetermined area of the road surface through one side of the arc-shape facing the road surface. The advantage of this design is that the majority of light may be irradiated to the road surface, thereby avoiding being irradiated to the roadside area. The road surface in this specification refers to the road surface of the road which needs to be irradiated by light, and the roadside refers to the area of two sides of the road which do not need to be irradiated usually, such as a green belt area, etc. In some embodiments, to simplify the manufacturing process, the inner wall 1311 of the curved surface reflector on one side of each reflector assembly 131 may also be designed as a left-right symmetric arc-shape along the direction vertical to the road surface 20, but at this time, a part of the light may be irradiated to the roadside area. [0033] Please refer to FIG. 7, a light distribution curve graph of the LED road lamp 10 of the present invention used for a specific road surface is shown. The inner wall 1311 of each reflector assembly 131 is respectively designed as a parabolic curved surface and a left-right non-symmetrical arc-shape along the directions parallel to and vertical to the road surface 20 as described above, therefore the LED road lamp 10 of the present invention may achieve long-distance irradiation towards two sides along the direction parallel to the road surface 20 (shown in FIG. 4), and the irradiation distance may be set over five times higher than the height of the lamp pole in order to ensure no shadow between light spots of the two adjacent road lamps 10. Furthermore, the LED road lamp 10 of the present invention may irradiate parallelly towards a center of the road surface long the direction vertical to the road surface (shown in FIG. 6), avoiding being irradiated to the roadside area, and greatly improving the utilization of light. It can be seen from the light distribution curve of FIG. 7 that, the light not only irradiates towards a long distance along two sides of the lamp pole, but also it irradiates towards the center of the road, greatly improving the luminous efficiency and meeting the irradiation requirements of the road surface. If a larger irradiated area is required, the modular reflector assemblies 131 are correspondingly added. Thus, no matter in the irradiation distance, luminance uniformity and flexibility of adjusting luminous intensity, the LED road lamp 10 of the present invention achieves greater improvements than the conventional road lamps. [0034] Locations set for the LED light source 121 may also make fine adjustment in accordance with different light distribution requirements, for example, FIG. 8 illustrates the different embodiment from that of FIG.5. In the embodiment of FIG.8, the LED light source 121 is mounted in a centered position. The location of the LED light source 121 is usually fixed to a PCB board which is usually fixed onto the backboard 12. In order to facilitate to adjust the LED light source 121, a schematic view of another embodiment is illustrated in FIG. 9, in which the backboard 12 defines a sliding groove 123, and the PCB board 122 mounted with the LED light sources 121 may be slidably mounted in the sliding groove 123, for instance, it may slide to any position of a, b and c. So on the one hand, the location of the LED light source 121 may be adjusted by adjusting the position of PCB board 122 on the sliding groove 123; on the other hand, the PCB board 122 may be replaced easily, because the PCB board may sometimes malfunction, or the LED light source 121 with different power need to be replaced to meet the light distribution demands of different luminance efficiency. Moreover, the LED light source 121 of the present specification is not limited to only a LED light source, but also it includes other types of light sources suitable for the reflector module of the present invention, so the term "LED light source" is only used to refer to all such applicable light sources, especially the LED light source itself. [0035] As shown in FIG. 10, a schematic view of a LED road lamp 10 according to another preferred embodiment of this invention is shown. Compared to the embodiment of FIG. 1, the embodiment of FIG. 10 omits the above design of the backboard 12, the reflector module 13 is directly designed to a back-to-back symmetric structure, and other parts' design is similar to the embodiment of FIG. 1 which is no longer repeated herein. The LED road lamp of this embodiment may be applied to occasions which only need hanging, for example, it may be mounted on a top 15 of a tunnel through mountains. In unrestricted embodiments, the LED road lamp may be directly fixed onto the top 15 by a connector 14 without any lamp pole, and the connector 14 may be used to provide power and corresponding control signals to the LED light sources. To match with specific installation requirements, the LED road lamp 10 of the present invention may also make other corresponding structure changes which are not illustrated one by one with examples herein. [0036] While the disclosure has been illustrated and described in typical embodiments, it is not intended to be limited to the details shown, since various modifications and substitutions can be made without departing in any way from the spirit of the present disclosure. As such, further modifications and equivalents of the disclosure herein disclosed may occur to persons skilled in the art using no more than routine experimentation, and all such modifications and equivalents are believed to be within the spirit and scope of the disclosure as defined by the following claims. [0037] Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereto.

Claims

1. A LED road lamp comprising LED light sources and a reflector assembly, wherein the reflector assembly comprises a pair of back-to-back curved surface reflectors arranged symmetrically, wherein each of the curved surface reflectors is designed as a continuous parabolic curved surface along a direction parallel to the road surface for reflecting light emitted from the LED light sources, so that the light is irradiated to a predetermined area along the direction parallel to the road surface after reflection.

2. The LED road lamp of claim 1, wherein each of the curved surface reflectors is designed as a continuous left-right non-symmetrical arc-shape along a direction vertical to the road surface, and the LED light source located in each of the curved surface reflectors is installed on one side of the arc-shape back to the road surface to reflect light through one side of the arc-shape facing the road surface within a predetermined area along the direction vertical to the road surface.

3. The LED road lamp of claim 1 or 2, wherein the LED light sources are installed on two sides of a backboard, and the pair of curved surface reflectors are arranged respectively on the two sides of the backboard.

4. The LED road lamp of claim 3, wherein the backboard defines a sliding groove and the LED light sources are installed in the sliding groove by a PCB board which is movable in the sliding groove.

5. The LED road lamp of any one of the preceding claims, wherein the curved surface shape of each of the curved surface reflectors is formed on the basis of a plurality of contour lines calculated from a curve fitting algorithm.

6. The LED road lamp of any one of the preceding claims, wherein the curved inner wall of the curved surface reflector is designed as completely specular reflection.

7. A LED road lamp comprising a backboard mounted with LED light sources and a reflector module for light reflection, wherein the reflector module comprises a plurality of reflector assemblies, each reflector assembly comprises a pair of back-to-back curved surface reflectors arranged symmetrically on two sides of the backboard, and each curved surface reflector is designed as a continuous parabolic curved surface along a direction parallel to the road surface for reflecting light emitted from the LED light sources, so that the light is irradiated to a predetermined area along the direction parallel to the road surface after reflection.

8. The LED road lamp of claim 7, wherein each of the curved surface reflectors is designed as a continuous left-right non-symmetrical arc-shape along a direction vertical to the road surface, and the LED light source in each of the curved surface reflectors is installed on one side of the arc-shape back to the road surface to reflect light through one side of the arc-shape facing the road surface within a predetermined area along the direction vertical to the road surface.

9. The LED road lamp of claim 7 or 8, wherein the plurality of reflector assemblies are mounted side by side on the backboard in parallel.

10. The LED road lamp of any one of claims 7 to 9, wherein the reflector module is detachably mounted with one or more reflector assemblies.