AU2008200821B2

AU2008200821B2 - Method for distributing light, light-distributing cup and street lamp adopting the same

Info

Publication number: AU2008200821B2
Application number: AU2008200821A
Authority: AU
Inventors: Chifai Cheung; Ben Fan; Jinbo Jiang; Wingbun Lee; Sandy To
Original assignee: Heshan Lide Electronic Enterprise Co Ltd
Current assignee: Heshan Lide Electronic Enterprise Co Ltd
Priority date: 2007-10-13
Filing date: 2008-02-22
Publication date: 2010-10-21
Anticipated expiration: 2028-02-22
Also published as: KR20090037783A; JP2009099526A; CN100591987C; KR100994969B1; AU2008200821A1; CN101255974A; WO2009046586A1

Description

Regulation 3.2 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: He Shan Lide Electronic Enterprise Company Ltd, Jinbo Jiang and Sandy To Actual Inventors: Ben Fan Jinbo Jiang Sandy To Wingbun Lee Chifai Cheung Address for Service: C/- MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention title: METHOD FOR DISTRIBUTING LIGHT, LIGHT DISTRIBUTING CUP AND STREET LAMP ADOPTING THESAME The following statement is a full description of this invention, including the best method of performing it known to us. I PatAU132 METHOD FOR DUSTRUBUTING LIGHT, LIGHT-DISTRIBUTING CUP AND STREET LAMP ADOPTING THE SAME BACKGROUND OF THE INVENTION 5 The present invention relates to a method for designing the path of light, more particularly, it relates to a method for distributing light; the present invention also relates to a lighting accessory, and in particular to a light distributing cup; moreover, the present invention relates to a street lamp adopting the light distributing cup. 0 The street lamp normally comprises a lamp pole, a lamp head installed on the top of the lamp pole, a light distributing cup provided in the lamp head and a light source provided in the light distributing cup. The light emitted by the point light source presents the Lambert radiation in three dimensional space. Commonly, for exclusive use of roadway lighting, the downward illumination is 5 sufficient. Therefore, the main function of the light-distributing cup is to reflect those upward or horizontal light emitted by the point light source to be downward so as to improve the light efficiency. The conventional light-distributing cup used to be a horn shape and the light will result in a round light spot after affected by such light-distributing cup. The reflection wall of such light-distributing cup is not an ideal design, so that a part of the light can only radiate out of the light-distributing cup after secondary 0 or several times reflection, even worse, a part of light fails to be reflected outward ultimately and leads to a waste of light energy. Moreover, such light-distributing cup forms a round light spot when radiating on the road, so that a part of the light emitted from the light-distributing cup will radiate beyond the roadway and another part of light will overlap which emitted by the street lamp on the other side of road and results in the waste of light energy. Meanwhile, more street lamps are required to be installed within a -5 unit distance to ensure the successive brightness on the road, because the light of the street lamp can distributes merely in small range. SUMMARY OF THE INVENTION 30 According to a first aspect of the present invention, there is provided a method for distributing light, including: radiating a first part of light emitted by a light source out from an opening of a light-distributing cup directly; radiating a second part of light emitted by the light source on an interior wall of the light 35 distributing cup; and reflecting the second part of light from the interior wall of the light-distributing cup out from the opening of the light-distributing cup; wherein the maximum beam angle of the first part of light is substantially equal to the beam angle of the second part of light reflected from an edge of the opening. According to a second aspect of the present invention, there is provided a light-distributing cup, 5 including: a bottom; side walls surrounding the bottom to form an opening; and a reflection layer provided on interior surfaces of both the bottom and the side walls; wherein the opening allows a first part of light emitted by a light source out from the light 0 distributing cup directly; and the reflection layer reflects out from the opening of the light-distributing cup a second part of light emitted by the light source on the reflection layer, and wherein the maximum beam angle of the first part of light is substantially equal to the beam angle of the second part of light reflected from an edge of the opening. 5 According to a third aspect of the present invention, there is provided a street lamp, including: a lamp pole; at least one light-distributing cup, installed at the top of the lamp pole, including a bottom; side walls surrounding the bottom to form an opening; and a reflection layer provided on the interior surfaces ,0 of both the bottom and the side walls; a light source in the at least one light-distributing cup; wherein the opening allows a first part of light emitted by a light source out from the light distributing cup directly; and the reflection layer reflects out from the opening of the light-distributing cup a second part of '5 light emitted by the light source on the reflection layer, the maximum beam angle of the first part of light is substantially equal to the beam angle of the second part of light reflected from an edge of the opening. An object of the present invention is to solve the problems described above and provide a method for distributing light, which is capable of transforming the light in the form of 30 Lambert radiation emitted by the point light source into an even and rectangular light spot. The above-mentioned object can be achieved by the following 5 technical solution: A method for distributing light, wherein a part of light emitted by the light source radiates out from the light-distributing cup directly, and the other part of light emitted by the light source radiates on the interior wall of the 10 light-distributing cup and then is also reflected out from the light-distributing cup. The part of light radiating outwards directly forms a rectangular main light spot. The other part of light radiating on the interior wall firstly and reflected by the light-distributing cup forms a rectangular light spot overlapped 15 with the rectangular main light spot. Therefore, the advantages of the present invention are: the present invention is capable of transforming the light emitted by the point light source into rectangular light spot, which is 20 desirable for use in the long and narrow space; the light radiating on the interior wall and reflected by the light-distributing cup forms a rectangular light spot overlapped with the main light spot, which enables the present invention to have higher light efficiency and brightness and evener light spot. 25 Furthermore, the present invention can be further improved by the following technical solutions: The beam angle that forms the main light spot is a predetermined 30 value. The beam angle of the light reflected from the interior wall of light-distributing cup is equal to that of the main light spot. The beam angle of the reflected light changes gradually from the opening to the bottom of the light-distributing cup within the predetermined scope. As mentioned above, the beam angle 35 forming the main light spot is a predetermined value, the relationship of the distance between the light source and the illumination object and the dimension of light spot can be calculated according to the Pythagorean theorem, so that the illumination brightness and illumination area can be determined. 40 Meanwhile, the beam angle of the light reflected from the opening of light-distributing cup is equal to that of the main light spot, and the beam angle of the reflected light changes gradually from the opening to the bottom of the light-distributing cup within the predetermined scope, which enables the light spot to overlap 2 in the dim circumference of the main light spot, so that the light spot becomes evener. The beam angle of the light radiating on the interior wall 5 of the light-distributing cup changes uniformly from the opening to the bottom of the light-distributing cup. In longitudinal direction of the light-distributing cup, the beam angle of the main light spot is 30 ,the beam angle of the 10 reflected light radiating on the interior wall of the light-distributing cup changes from 30*to O 0 gradually; while in latitudinal direction of the light-distributing cup, the beam angle of the main light spot is 620, the beam angle of the reflected light radiating on the interior wall of the light-distributing 15 cup changes gradually from62* to30*,so that it can generate a 40X12m light spot when the distance between the light source and illumination object is 12m. Another object of the present invention is to provide a 20 light-distributing cup capable of transforming the light emitted by the point light source into rectangular light spot with higher light efficiency, higher brightness and evener illumination. The above object is achieved by the following technical 25 solution: A light-distributing cup comprises a bottom and side walls, a reflection layer is provided on the interior surfaces of both the bottom and the side walls, wherein the bottom is rectangular 30 and the interior surface of the light-distributing cup is cambered and recessed inwardly, the side walls are provided to surround the cup body circumferentially to form a rectangular opening. The advantages of the present invention are: the rectangular 35 opening of the light-distributing cup is capable of generating rectangular light spot, which enables the present invention to be used in the long and narrow space and assures the light radiating out of the light-distributing cup to be rectangular. Meanwhile, the interior surface of the side wall recesses inwardly and 40 surrounds the cup body circumferentially to form a rectangular opening so that the reflected light capable of forming rectangular light spot similar to the main light spot. The light spot formed by reflected light overlaps the main light spot, so that the brightness and light efficiency will be higher and the light spot 3 will be evener. Preferably, the main beam angle is a predetermined value, the concave curved surface of the side walls is a free curved surface calculated by the Snell's Law. The beam angle of the light reflected from 5 the opening of the cup is equal to the main beam angle. The beam angle of the reflected light changes gradually from the opening to the bottom of the light-distributing cup within the predetermined scope. Preferably, the structure of the side walls allows the beam angle of reflected light changes uniformly from the opening to the bottom of the light-distributing cup. 0 Preferably, in longitudinal direction of the light-distributing cup, the beam angle of the main light spot is 300 while the beam angle of the reflected light changes gradually from the opening to the bottom within 300 to 0' in sequence. 5 Preferably, in latitudinal direction of the light-distributing cup, the beam angle of the main light spot is 62* while the beam angle of the reflected light changes from the opening to the bottom within 620 to 30 in sequence gradually. Preferably, a light source mounting hole is provided in the centre of bottom of the light 0 distributing cup. Preferably, the reflection layer is a dielectric firm or a metal lamina. Alternatively, the reflection layer is an aluminium coating layer. .5 It is still an object of the present invention to provide a street lamp capable of generating rectangular light spot on the ground with higher brightness and evener illumination. The above object is achieved by the following technical solution: 30 A street lamp comprises a lamp pole, a light-distributing cup installed in the lamp head and a light source provided in the light-distributing cup, wherein the light-distributing cup is the light distributing cup described above, the longitudinal direction of the light-distributing cup is parallel to roadway.

A

The advantages of the present invention are: comparing with conventional round light spot, the light-distributing cup in present invention capable of generating rectangular light spot 5 with higher brightness and evener illumination under the same light intensity, which allows the distance between two street lamps to extend longer. Thus, the quantity of street lamps installed on the roadway within unit length can be reduced to realize power consumption. 10 Preferably, a plurality of light-distributing cups is provided on the top of the lamp pole, a light source is provided in each light-distributing cup. 15 Preferably, the light-distributing cups are arranged in arrays or interlacement. Preferably, the light source is high-power LED. 20 BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the present invention w ill become clear by the following description, provided as non limiting example, to be read with reference to the accompanying 25 drawings, in which: FIG.1 is a schematic view of the structure of the light-distributing cup according to a preferred embodiment of the present invention. 30 FIG.2 is a schematic sectional view of the interior wall of the light-distributing cup according to a preferred embodiment of the present invention. FIG.3a is a schematic diagram showing the light-distributing 35 cup of the present invention reflecting the light in the latitudinal direction. FIG.3b is a schematic diagram showing the iight-distributing cup of the present invention reflecting the light in the 40 longitudinal direction. FIG. 4 is the mathematical model of the section curve of curved surface of the side wall of the light-distributing cup of the present invention. 5 FIG.5 is a schematic view of the structure of the street lamp according to the first embodiment of the present invention. 5 FIG.6 is a first schematic view of the structure of the street lamp according to the second embodiment of the present invention. FIG.7 is a second schematic view of the structure of the lamp head according to the second embodiment of the present invention. 10 FIG.8 is a third schematic view of the structure of the lamp head according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION 15 Referring to FIG.1 and FIG.2, the light-distributing cup 1 is a rectangular cavity. The bottom 11 is rectangular with a light source mounting hole provided in the center. In the present invention, the light source is preferred to be a point light source 20 14 capable of emitting light in the form of Lambert radiation. The point light source 14 may be a known light source such as high-power LED, tungsten lamp or fluorescent lamp. The side walls 12,13 surround the bottom of the cup to form a rectangular opening. A reflection layer is provided on the surfaces of the bottom 11 25 and the side walls 12,13. The reflection layer can be a medium lamina (i.e. TiO 2 , Si02 or MgF 2 ) or a metal lamina (i.e. aluminum coating or argentums coating), or can be obtained by polishing the surfaces of the bottom 11 and the side walls 12,13 directly to achieve the proper reflection effect. Any other method capable 30 of assuring the curved surface to achieve such reflection effect can also be adopted. The side walls 12,13 are designed to reflect the light emitted by the point light source 14 in center of the bottom 11 outwards 35 from the light-distributing cup 1 once for all, which avoids the waste of light energy due to the repeated reflection of the light inside the light-distributing cup 1. It can be achieved by precisely designing the angle formed by the side walls 12,13 and the bottom 11 according to the Snell's law. However, for 40 controlling the angle of reEleocted light changing in a small 1 range, it is preferred to design the side walls 12, 13 as a concave curved surface so as to control the shape of the light spot generated by the light-distributing cup 1 and the brightness of the light spot in each area. 6 The structure and the design principle of the light-distributing cup 1 are illustrated as below with the side wall 13 in longitudinal direction given as an example, as shown 5 in FIG.3b and FIG.4, regarding the center of the bottom 11 (where light source 14 is positioned) as an origin to establish a two-dimensional coordinate system with the vertical direction as axis Y and the horizontal direction as axis X. The beam angle of the main light spot is the widest angle between the light radiated 10 directly outwards from the light-distributing cup and the axis (axis X in FIG.4) of the light-distributing cup, in other words, it is the angle formed by the light that radiates exactly through the border of the light-distributing cup and the axis of the light-distributing cup. The beam angle of the main light spot 15 influences the shape and brightness of the light spot greatly. If the distance between the light source 14 and the illumination object remains constant, once the beam angle becomes wider, the area of the light spot becomes bigger accordingly and the light intensity becomes lower, on contrary, the beam angle becomes 20 narrower, the area of the light spot becomes smaller, and the light intensity becomes higher. The designers can calculate the beam angle according to Pythagorean theorem in actual applications. For instance, if this invention is adopted in street lamp then the beam angle for reference is 3 0 'and the installed height is 25 12m, the width of the light spot is 13.8m. The beam angle of the reflected light is the angle formed by any re Hected light radiaLing on the interior wail 13 of the light-distributing cup 1 and the axis of the light-distributing 30 cup 1. In the present invention, the light is reflected by the side wall 13, so that the light spot formed by the reflected light has the similar shape as that of the main light spot. Then, the beam angle of each light reflected by the side wall 13 is controlled by the curvature of the light-distributing cup 1, and thus the 35 shape and brightness of the light spot is controlled, so that the light spot can be added to the dim area of the main light spot to achieve an evener brightness. The widest beam angle is the angle between the reflected light radiating on the uppermost point of side wall 13 and the axis of the light-distributing cup. It is 40 an object of the present invention to add the light spot to the dim periphery of the main light spot. The widest beam angle should be equal. to that of the main light spot, thus, the light radiating on the left edge of the opening of the light-distributing cup can be reflect-ed to the rightmost edge of the main light spot. Then, 7 the beam angle of the light reflected by the interior wall under the opening of the light-distributing cup reduces in geometric proportion, and the reflected light shifts to the interior of the main light spot, so that the intensity of the light spot becomes 5 stronger from the exterior to interior, and the overall brightness becomes evener eventually. The light-reflecting curved surface that realizes the above-mentioned reflection effect is a free curved face 10 calculated by Snell's Law and integral iterative method. Referring to FIG.4, the cross section curve of the curved surface should satisfy the following equations: Tan(a)= L " = tan - - (,# - a) Ax, 2 711 p=+-(at -0) i5 4 2 y., = + A,%' - X = + AN., For example, the coordinates of the points on the curve Ls determined according to the following factors: the height of side 20 wall 13 (axis Y of the opening of the light-distributing cup) is 10mm, the width of bottom of the light-distributing cup is 6mm, the beam angle of the main light spot is 300, the beam angle of the reflected light radiating on the side wall 13 of the light-distributing cup changes gradually within 30 0 to 0 0from the 25 opening to the bottom of the light-distributing cup in geometric proportion. The height of the side wall is divided into one thousand integral points, thus: Ay=0. 01 AO=0.03O 30 In above equations, n is the current point of the calculated numerical value, n+1 is the next point of the calculated numerical value, Ax and Ay are the variable micro quantum in direction of axis x and y. Based on the initial condition: X, =0 P0 354 8 N= 3 yo= 0 The coordinate of each point from the bottom up can be calculated by integral iterative method according to the equations listed above, for instance, the coordinate of the first 5 point is (3.00577, 0.01), the coordinate of the second point is (3.01152, 0.02), the coordinate of the third point is (3.01726, 0.03)...... and the last point is (5.77350, 10) . In this embodiment, it is divided into one thousand integral points in direction of axis Y, and the integral points can be widened or shortened 10 according to requirements of actual precision. Similarly, the free curved surface of side wall in latitudinal direction of the light-distributing cup. The beam angle of main light spot in latitudinal direction of the light-distributing cup is 62*, the beam angle of the reflected light radiating on the side wall 13 15 of the light-distributing cup changes gradually from the opening to the bottom from 62 0 to 30 0 in geometric proportion. When such light-distributing cup 1 is installed at a height of 12m, a 40m x 13.8m of even and rectangular light spot can be obtained. The calculation of points can be finished by computer software, then 20 connect every point into a smooth curve. Afterwards, a model is established by the computer drawing software, and finally manufacture is carried out by digital controlled machining or precise foundry. 25 Referring to FIG.5, in the first embodiment of a street lamp adopting the above-described light distributing cup 1, the light-distributing cup 1 is mounted on the top of the lamp pole 2, a light source 14 is provided in the light-distributing cup 1, which can be a high pressure sodium lamp or a high-power LED, 30 and the longitudinal direction of the light-distributing cup is parallel to roadway. Comparing with conventional round light spot, the light-distributing cup in present invention is capable of generating rectangular light spot with higher brightness and evener illumination under the same light intensity, which allows 35 longer distance to be arranged between two street lamps. Thus, the numbers of street lamps installed on the road within unit length can be reduced to realize power consumption. In addition, a reflection panel 15 with diffusing structure can be provided in the front of the light-distributing cup to protect the passerby 40 from feeling dizzy. Referring to FIGS.6, 7 and 8, in another embodiment of the street l amp, a lamp head 3 is mounted on the top of the lamp pole, 9 a plurality of light-distributing cups 1 is provided in the lamp head 3, a light source 14 is provided in each light-distributing cup 1, the longitudinal direction of all light-distributing cups are parallel to the roadway, a plurality of light-distributing 5 cups 1 can be interlaced as shown in FIG.7 or can be arranged in arrays as shown in FIG.8. The size and brightness of the light spot are related to the quantity of LEDs. The various installed heights and testing data of the street lamp with different quantity of LEDs of the present 10 invention, which Users can select freely according to their actual applications, are shown as follow: Average Average Average Average Distance Installed Luminance of Luminance of 60 Luminance of Luminance of between Roadwidth Height 30 LEDs/ LEDs/ 90 LEDs/ 120 LEDs/ lamp poles Uniformity Uniformity Uniformity Uniformity Luminous 15501' 35991m 42251m 60751m Flux 4m 17 LUX/ri..28 35LUX/0.26 12m 5m 13LUX/D.38 26 LUX/0.36 15m 6m 8.92LUX /0.37 19LUX/0.43 27LUX/0.39 40 LUX/0.33 18m 7m 14 LUX/0.49 20 LUX/0.44 30LUX/0.37 21m Two- way 8m llLUX/0.54 16 LUX/0.5 23 LUX/0.44 24m traffic 9m 8.55LUX/0.54 12 LUX/0.5 19LUX/0.47 27m (7m) lOm 6.93 UX/0.60 10 LUX/0.56 15 LUX/0.48 30m 11m 8.21 UX/0.56 13LUX/0.5 33m 12m 6.82 UX/0.52 10 LUX/0.52 36m Wherein: 15 The luminou~s flux is tested in one street lamp; the adopted power of the LED is 1W; the luminous flux for each LED is 70-801m. 10 A detailed description of one or more preferred embodiments of the invention is provided above along with accompanying figures that illustrate by way of example the principles of the invention. While the invention is described in connection with such embodiments, it should be understood that the invention is not limited to any embodiment. On the contrary, the scope of the invention is limited only by 5 the appended claims and the invention encompasses numerous alternatives, modifications, and equivalents. For the purpose of example, numerous specific details are set forth in the description above in order to provide a thorough understanding of the present invention. The present invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in 0 detail so that the present invention is not unnecessarily obscured. Throughout this specification and the claims that follow unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or 5 group of integers. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge of the technical field. .0 1 1

Claims

1. A method for distributing light, including: radiating a first part of light emitted by a light source out from an opening of a light distributing cup directly; 5 radiating a second part of light emitted by the light source on an interior wall of the light distributing cup; and reflecting the second part of light from the interior wall of the light-distributing cup out from the opening of the light-distributing cup; wherein the maximum beam angle of the first part of light is substantially equal to the beam 0 angle of the second part of light reflected from an edge of the opening.

2. The method according to claim 1, wherein the first part of light forms a first light spot.

3. The method according to claim 2, wherein the second part of light forms a second light spot, .5 and the first and the second light spot are approximately the same size.

4. The method according to any one of claims I to 3, wherein the beam angle of the reflected light changes gradually from a maximum at the edge of the opening to a minimum at a bottom of the light-distributing cup. !0

5. The method according to any one of claims I to 4, wherein in a longitudinal direction of the light-distributing cup, the maximum beam angle of the first part of light is about 300, the beam angle of the reflected light changes from about 30* at the edge of the opening to about 00 at the bottom of the light-distributing cup. 25

6. The method according to any one of claims I to 5, wherein in a latitudinal direction of the light-distributing cup, the maximum beam angle of the first part of light is about 62*, the beam angle of the reflected light changes from about 620 at the edge of the opening to about 300 at the bottom of the light-distributing cup. 30

7. A light-distributing cup, including: a bottom; side walls surrounding the bottom to form an opening; and a reflection layer provided on interior surfaces of both the bottom and the side walls; 35 wherein the opening allows a first part of light emitted by a light source out from the light distributing cup directly; and 12 the reflection layer reflects out from the opening of the light-distributing cup a second part of light emitted by the light source on the reflection layer, and wherein the maximum beam angle of the first part of light is substantially equal to the beam angle of the second part of light reflected from an edge of the opening. 5

8. The light-distributing cup according to claim 7, wherein the surface of the side walls is a curved surface with a curvature calculated by Snell's Law.

9. The light-distributing cup according to claim 7 or 8, wherein the surface of the side walls is 0 curved such that the beam angle of the reflected light changes gradually from a maximum at the edge of the opening to a minimum at the bottom of the light-distributing cup.

10. The light-distributing cup according to any one of claims 7 to 9, wherein in a longitudinal direction of the light-distributing cup, the maximum beam angle of the first part of light is about 300, 5 the beam angle of the reflected light changes from about 30 at the edge of the opening to about 0* at the bottom of the light-distributing cup.

I1. The light-distributing cup according to any one of claims 7 to 10, wherein in a latitudinal direction of the light-distributing cup, the maximum beam angle of the first part of light is about 62', 0 the beam angle of the reflected light changes from about 62* at the edge of the opening to about 300 at the bottom of the light-distributing cup.

12. The light-distributing cup according to any one of claims 7 to 11, wherein a light source mounting hole is provided in the centre of the bottom of the light-distributing cup. 25

13. The light-distributing cup according to any one of claims 7 to 12, wherein the reflection layer is a dielectric film.

14. The light-distributing cup according to any one of claims 7 to 12, wherein the reflection layer 30 is a metal lamina.

15. The light-distributing cup according to any one of claims 7 to 12, wherein the reflection layer is an aluminium coating layer. 35

16. A street lamp, including: a lamp pole; 13