WO2015007597A1

WO2015007597A1 - Lens for illuminating device and illuminating device comprising the lens

Info

Publication number: WO2015007597A1
Application number: PCT/EP2014/064751
Authority: WO
Inventors: Xueqin LIN
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2013-07-17
Filing date: 2014-07-09
Publication date: 2015-01-22
Anticipated expiration: 2016-01-17
Also published as: CN104296068A

Abstract

The present invention relates to a lens for a light source, comprising a bottom surface defining a recessed region at its center and a top surface rising from the bottom surface, wherein a surface of the recessed region comprises an incident surface disposed at its center and a reflective surface disposed around the incident surface, first incident light from the light source reaches and exits the top surface in a first direction after being refracted by the incident surface to form a first emergent light for forward illumination, and second incident light from the light source is reflected, when being emitted to the reflective surface, and then exits in a second direction to form a second emergent light for backward illumination. The present invention further relates to an illuminating device using the lens.

Description

Lens for Illuminating Device and Illuminating Device

Comprising the Lens

Technical Field

The present invention relates to a lens for a illuminating device and an illuminating device comprising the same.

Background Art

Solid-state lighting (SSL) devices use light emitting diodes (LEDs) and tend to evolve quickly and gradually replace tra^¬ ditional lighting such as incandescent and fluorescent lamps. LEDs have advantages such as low energy consumption and high efficiency, long lifetime and compact design, which enable the LED devices to be an alternative to the traditional illu^¬ minating devices in many situations. The prior art provides many improvements to achieve an omnidirectional illumination effect based on the LED technology.

In the prior art, Patent Document EP 2180234 Al discloses an invention which provides an omnidirectional light bulb com^¬ prising a transparent body member and a contact member at one end of the body member. The light bulb further comprises a disc and a supporting pole disposed therein and is provided with a plurality of LEDs in a circumferential direction of the disc, thus an appropriate illumination effect can be pro^¬ vided in all directions. Patent Document WO2009/091562A2 dis^¬ closes an invention which provides a light bulb provided therein with an LED support and provided with a plurality of LEDs at each surface of the LED support so as to achieve mul- tidirectional or omnidirectional illumination. However, both the inventions need to use a plurality of LED chips as a ba^¬ sis for achieving multidirectional or omnidirectional illumi- nation, which not only increases production cost but also limits the application environment of the products.

Summary of the invention

To overcome the above technical problem, the present inven- tion provides a novel lens for an illuminating device. An il^¬ luminating device based on the lens can achieve multidirec^¬ tional or omnidirectional illumination and achieve a uniform light distribution in all directions by using a single LED chip instead of a plurality of LED chips in addition to the lens providing light exiting in a forward direction and light reflected by the lens and exiting in a backward direction, thus the production process is simplified, and also the pro^¬ duction cost is reduced. Moreover, leakage of light for for^¬ ward illumination can be prevented by using a design of a re- flective surface in the lens.

A first object of the present invention is achieved by a lens for a light source, comprising a bottom surface defining a recessed region at its center and a top surface rising from the bottom surface, wherein a surface of the recessed region comprises an incident surface disposed at its center and a reflective surface disposed around the incident surface, a first incident light from the light source reaches and exits the top surface in a first direction after being refracted by the incident surface to form first emergent light for forward illumination, and a second incident light from the light source is reflected, when emitted to the reflective surface, and then exits in a second direction to form second emergent light for backward illumination. According to such design, after passing through the lens, light from the light source can achieve an illumination effect simultaneously in multiple directions such as two opposite directions to achieve the possibility of illumination in all directions. According to the present invention, the first emergent light and the second emergent light jointly achieve omnidirectional illumination. The possibility of illumination in multiple or all directions can be achieved by emergent light in both di- rections.

Preferably, the incident surface is designed to be transpar^¬ ent or semitransparent so that the first light is transmitted directly through the incident surface and then refracted and exits through the top surface. Thus, the first light from the light source can exit from the exit surface directly after transmitted through the incident surface and can form emer^¬ gent light directly in the forward direction along the opti^¬ cal axis .

Preferably, a surface of the reflective surface that faces the light source is provided with a reflective coating by which the second light is reflected. Thus, the possibility is achieved that the second light from the light source is re^¬ flected and exits in a direction opposed to the incident di^¬ rection after being subjected to the action of the reflective coating.

Preferably, the reflective coating is a mirror reflective coating. Such reflective coating appropriately allows the se^¬ cond light from the light source to be reflected with high efficiency . Preferably, viewed from section of the lens, the incident surface is designed to have any shape selected from a semi^¬ circle, a rectangle and a trapezoid. Light incident through the incident surface can form light distributions in differ^¬ ent forms after being incident according to different con- tours. Preferably, the reflective surface comprises a first portion and a second portion, the second light exits after being re^¬ flected by at least the second portion. The first portion connects the second portion of the reflective surface to the incident surface when viewed in section of the lens, so that all the light from the light source is subjected to the ac^¬ tion of the incident surface or the reflective surface and the second light is reflected by the second portion of the reflective surface. Preferably, viewed from section of the lens, the first por^¬ tion is designed to have a line shape, and the second portion is designed to form any of a line and a spline curve. Accord^¬ ing to the design of the first portion, an angle between the second portion connected to the first portion and the bottom surface of the lens can be changed to achieve the possibility of changing an exit angle of the emergent light reflected by the second portion.

Preferably, viewed from section of the lens, the first por^¬ tion is gradually away from an optical axis of the lens from the bottom surface to the top surface. An effective boundary is formed between the reflective surface and incident sur^¬ face, the second light is incident on the reflective surface only .

Preferably, viewed from section of the lens, the first por- tion and the second portion jointly form a continuous spline curve, when. Thus, the second light from the light source can be subjected to the action of both the first portion and the second portion and reflected to exit toward the bottom sur^¬ face . Preferably, viewed from section of the lens, the first por- tion and the second portion are jointly formed to be gradual^¬ ly close to an optical axis of the lens from the bottom sur^¬ face to the top surface. The so formed reflective surface is capable of controlling the emergent angle of the second light after being reflected.

Preferably, the top surface comprises an exit surface and a demoulding surface disposed around the exit surface, the first light exiting through the exit surface after passing through the incident surface. According to such design, light exiting in a forward direction exits only through the exit surface, and moreover, the use of the demoulding surface makes it easier to manufacture and machine the lens while not affecting the illumination effect in the forward direction.

Preferably, the exit surface is designed to form a spline curve when viewed from section of the lens. Thus, uniform circumferential illumination in the forward direction can be formed by the light refracted by the exit surface.

Preferably, the demoulding surface is designed to form any of a spline curve and a line when viewed in section of the lens. Such demoulding surface facilitates the possibility of sim^¬ plified machining or manufacture of the lens.

Preferably, the lens is designed to be rotationally symmet^¬ rical around an optical axis. Such lens can form a rotation- ally symmetrical light distribution of the emergent light. Preferably, the lens is made of any of optical plastic and glass. Such materials allow the lens to have a suitable eco^¬ nomic property while having an excellent optical performance.

Another object of the present invention is achieved by an il- luminating device comprising a light source and a lens de^¬ scribed above. Such illuminating device can achieve an illu^¬ mination effect in all directions by the aid of the lens.

Preferably, the illuminating device is designed as an LED retrofit lamp. Such retrofit lamp can be advantageously com^¬ patible with platforms of other illuminating devices and pro^¬ vide a good economical applicability to widen the application environment .

Preferably, the LED retrofit lamp is an A-type retrofit lamp. Therefore, it can be compatible with a shape of a traditional light bulb in appearance and performance and has an excellent omnidrectional illumination performance similar to that of the traditional light bulb.

Preferably, the illuminating device further comprises a heat sink designed as a plurality of heat sink fins disposed in a circumferential direction at a peripheral of the illuminating device, and viewed from section of the illuminating device, the heat sink fin comprises a first edge which is designed to be inclined away from an optical axis of the lens in a direc- tion from the top surface to the bottom surface of the lens, when. According to such design, light passing through the lens is prevented from being blocked or obstructed by the structural design of the heat sink to decrease the illumina^¬ tion effect. Brief Description of the Drawings

The drawings constitute a portion of the Description for fur^¬ ther understanding of the present invention. These drawings illustrate the embodiments of the present invention and ex^¬ plain the principle of the present invention together with the Description. In the drawings, the same part is represent- ed by the same reference numeral. In the drawings,

Fig. 1 is a sectional schematic view of a lens according to an embodiment of the present invention;

Fig. 2 is a optical path diagram of the lens according to an embodiment of the present invention; and

Fig. 3 is a sectional schematic view of an illuminating de^¬ vice according to an embodiment of the present invention.

Detailed Description of the Embodiments

Fig. 1 is a sectional schematic view of a lens 100 according to an embodiment of the present invention. As shown in Fig. 1, the lens 100 can be designed to be rotationally symmet^¬ rical with respect to an optical axis X and may be made of optical plastic or glass, thus the production cost is re^¬ duced, and also an excellent optical performance of the lens 100 can be ensured. The lens 100 has a top surface 2 and a bottom surface 1 disposed opposite to the top surface 2, an incident surface 41 and a reflective surface 42 of the lens and a recessed region 3 for accommodating a light source 5 are defined between the bottom surface 1 and the top surface 2, the recessed region 3 is designed to be hollow, and as can be seen from the figure, the incident surface includes two parts, i.e., the incident surface 41 and the reflective sur^¬ face 42.

Refer to Fig. 2 which is a optical path diagram of the lens 100 according to an embodiment of the present invention. An LED light source 5 having advantages such as low energy consumption, high efficiency and long lifetime can be disposed at the center of the bottom surface 1, thus light from the LED light source 5 is incident into the lens 100 and reaches the incident surface after entering the bottom surface 1. First light LI from the light source 5 is incident directly on the incident surface 41, and at this time, the first light LI is refracted on the incident surface 41 to the top surface 2, and further refracted by the top surface 2 and then emit^¬ ted to the outside of the lens 100. A contour of the incident surface 41 may have different designs, and for example, may be designed into any shape selected from a semicircle, a rec^¬ tangle and a trapezoid when viewed from section, the contour of the incident surface 41 is, of course, not limited to the above shapes, any similar shape capable of achieving the same or similar function can be used to be designed as the contour of the incident surface 41, and therefore the first light LI incident from the incident surface 41 can have different light distributions, thereby forming light distributions of emergent light LI' with different effects after finally exit^¬ ing through the top surface 2. It should be noted that the top surface 2 includes two parts which are respectively an exit surface 21 and a demoulding surface 22, after being re- fracted by the incident surface 41, the first light LI from the light source 5 is refracted only by the exit surface 21 and then exits (the details will be described hereinafter) , thus no light from the light source 5 is emitted through the demoulding surface 22, the demoulding surface 22 is connected to the exit surface 21 of the top surface 2 and the bottom surface 1 so that the whole lens 100 has a continuous periph^¬ eral contour, and such design provides a contour design which is easy to machine or manufacture during the manufacture of the lens 100, and facilitates, for example, the process of demoulding.

As shown in Fig. 1, the reflective surface 42 as the other incident surface is disposed around the incident surface 41 and is rotationally symmetrical with respect to the optical axis X of the lens 100 around the incident surface 41. When viewed from section of the lens 100, the reflective surface 42 may be disposed to have two portions, i.e., a first por^¬ tion 421 and a second portion 421, wherein the first portion 421 can be disposed in a line shape when viewed from section, and the second portion 422 can be also disposed in a line shape, thus the first and second portions 421, 422 form a zigzag sectional contour as a whole. In this case, the first portion 421 can achieve the function of defining a boundary between the first light LI and second light L2 from the same light source 5, and the first light LI incident through the incident surface 41 is not incident onto the reflective sur^¬ face 42, thus the first light LI passes only through the in^¬ cident surface 41 to form final forward emergent light LI' . On this basis, when the second light L2 from the light source 5 is incident onto the reflective surface 41, since the re^¬ flective surface 42 is treated with, for example, a mirror reflective coating, the second light L2 is totally reflected directly by the reflective surface 42, then emitted towards a direction of the bottom surface 1, and finally exits through the bottom surface 1 to form emergent light L2' . According to such design, one part LI of light from the light source 5 forms, through the incident surface 41, a light distribution in a first direction which is the forward direction, and the other part L2 of the light from the light source 5 forms, af^¬ ter being reflected by the reflective surface 42, a backward light distribution, i.e., another light distribution after exiting in a second direction opposite to the first direc^¬ tion, and an omnidirectional illumination effect is finally provided based on the light distributions in different re^¬ gions .

As can be seen from Fig. 1, a light flux ratio of the first emergent light LI' exiting in the first direction to the se- cond emergent light L2' exiting in the second direction can be changed by changing a ratio between volumes of the inci^¬ dent surface 41 and the reflective surface 42 or between siz^¬ es of surface contours of the incident surface 41 and the re- flective surface 42 depending on the volumes or the sizes of the surface contours of the incident surface 41 and the re^¬ flective surface 42 when viewed from section of the lens 100.

Moreover, it should be noted that in an embodiment not shown, the two portions 421, 422 of the reflective surface 42 of the lens 100 can be designed into a line shape and a spline curve, respectively, thus different reflection effects or re^¬ flection effects with different exit angles can be finally provided for the second light L2, and thereby the adjustment of, for example, the light distribution and exit angle of the emergent light L2' from the light source 5 can be achieved so that an illumination range of the omnidirectional illumina^¬ tion processed by the lens 100 can be finally adjusted.

In another embodiment not shown, the two portions 421, 422 of the reflective surface 42 of the lens 100 can be designed in- tegrally, that is, the two portions 421, 422 are designed to form, for example, a spline curve when viewed from section of the lens 100, thus the manufacture process of the lens 100 can be simplified to a certain extent, and an excellent omni^¬ directional illumination effect can be achieved. Furthermore, an illuminating device 200 is provided based on the lens 100 described above, referring to Fig. 3 which il^¬ lustrates a sectional schematic view of the illuminating de^¬ vice 200 according to an embodiment of the present invention. According to such design, the lens 100 can be disposed at a top of the illuminating device 200 to receive light from an LED light source to provide illumination in a forward direc- tion which is a direction from the bottom surface to the top surface of the lens 100 while providing illumination in a backward direction which is a direction from the top surface to the bottom surface of the lens 100, thereby forming a light distribution of omnidirectional illumination of the il^¬ luminating device 200. In order to prevent a traditional heat sink 6 designed at a periphery of the illuminating device 200 from blocking or obstructing backward light from the lens 100, the heat sink 6 in the illuminating device 200 is de- signed with heat sink fins 61, and the heat sink fin 61 is designed to have a first edge 611 which is inclined gradually close to the optical axis X in a direction from the bottom to the top of the illuminating device 200, thus it is avoided that downward light from the lens 100 is blocked or obstruct- ed by the heat sink fin 61 and as a result the whole omnidi^¬ rectional illumination effect is lowered or deteriorated if the first edge 611 is designed to be horizontal.

The above are merely preferred embodiments of the present in^¬ vention but not to limit the present invention. It would be understood by those skilled in the art that the present in^¬ vention may have various alterations and changes. Any altera^¬ tions, equivalent substitutions, and improvements, within the spirit and principle of the present invention, should be cov^¬ ered in the scope of the present invention.

, ^

Reference Numerals

1 bottom surface

2 top surface

3 recessed region

41 incident surface

42 reflective surface

421 first portion

422 second portion

5 light source

6 heat sink

61 heat sink fin

611 first edge

100 lens

200 illuminating device 21 exit surface

22 demoulding surface

LI first light

L2 second light LI' first exit light

L2' second exit light

X optical axis

Claims

Patent claims

1. A lens (100) for a light source (5), comprising a bottom surface (1) defining a recessed region (3) at its center and a top surface (2) rising from the bottom surface (1), characterized in that a surface of the recessed re^¬ gion (3) comprises an incident surface (41) disposed at its center and a reflective surface (42) disposed around the incident surface (41), a first incident light (LI) from the light source (5) reaches and exits the top sur^¬ face (2) in a first direction after being refracted by the incident surface (41) to form a first emergent light (LI') for forward illumination, and second incident light (L2) from the light source (5) is reflected, when being emitted to the reflective surface (42), and then exits in a second direction to form a second exit light (L2') for backward illumination.

2. The lens (100) according to claim 1, characterized in that the first emergent light (LI') and the second emer^¬ gent light (L2') jointly achieve omnidirectional illumi^¬ nation .

3. The lens (100) according to claim 1 or 2, characterized in that the incident surface (41) is designed to be transparent or semitransparent so that the first light (LI) is transmitted directly through the incident sur^¬ face (41) and then refracted and exits through the top surface (2 ) .

4. The lens (100) according to claim 1 or 2, characterized in that a surface of the reflective surface (42) that faces the light source (5) is provided with a reflective coating by which the second light (L2) is reflected.

The lens (100) according to claim 4, characterized in that the reflective coating is a mirror reflective coat^¬ ing .

The lens (100) according to claim 1 or 2, characterized in that viewed from section of the lens (100), the inci^¬ dent surface (41) is designed to have any shape selected from a semicircle, a rectangle and a trapezoid.

The lens (100) according to claim 1 or 2, characterized in that the reflective surface (42) comprises a first portion (421) and a second portion (422), the second light (L2) exits after being reflected by at least the second portion (422) .

The lens (100) according to claim 7, characterized in that viewed in section of the lens (100), the first por^¬ tion (421) is designed to have a line shape, and the se^¬ cond portion (422) is designed to form any of a line and a spline curve.

The lens (100) according to claim 8, characterized in that viewed in section of the lens (100), .the first portion (421) is gradually away from an optical axis (X) of the lens (100) in a direction from the bottom surface (1) to the top surface (2) .

The lens (100) according to claim 7, characterized in that viewed in section of the lens (100), the first por^¬ tion (421) and the second portion (422) jointly form a continuous spline curve.

11. The lens (100) according to claim 10, characterized in that viewed in section of the lens (100), the first por^¬ tion (421) and the second portion (422) are jointly formed to be gradually close to an optical axis (X) of the lens (100) in a direction from the bottom surface (1) to the top surface (2) .

12. The lens (100) according to claim 1 or 2, characterized in that the top surface (2) comprises an exit surface

(21) and a demoulding surface (22) disposed around the exit surface (21), the first light (LI) exiting through the exit surface (21) after passing through the incident surface (41).

13. The lens (100) according to claim 12, characterized in that viewed in section of the lens (100), the exit sur^¬ face (21) is designed to form a spline curve. 14. The lens (100) according to claim 13, characterized in that viewed in section of the lens (100), the demoulding surface (22) is designed to form any of a spline curve and a line. 15. The lens (100) according to claim 1 or 2, characterized in that the lens (100) is designed to be rotationally symmetrical around an optical axis (X) .

16. The lens (100) according to claim 1 or 2, characterized in that the lens (100) is made of any of optical plastic and glass.

An illuminating device (200) characterized in comprising a light source and a lens (100) according to any one of claims 1 to 16.

18. The illuminating device (200) according to claim 17,

characterized in that the illuminating device (200) is designed as an LED retrofit lamp.

19. The illuminating device (200) according to claim 18,

characterized in that the LED retrofit lamp is an A-type retrofit lamp.

20. The illuminating device (200) according to claim 17,

characterized in that the illuminating device (200) fur^¬ ther comprises a heat sink (6) designed as a plurality of heat sink fins (61) disposed in a circumferential di^¬ rection at peripheral of the illuminating device (200), and viewed in section of the illuminating device (200), the heat sink fin (61) comprises a first edge (611) which is designed to be inclined away from an optical axis (X) of the lens (100) in a direction from the top surface (2) to the bottom surface (1) of the lens (100) .