An LED Illumination Device Technical Field

The present invention relates to an LED illumination device. Background Art

Mountain climbing or camping usually needs a torch lamp and a camping lamp. The torch lamp is a very useful, versatile light source especially in the emergency case, and it is very convenient, for example, in electricity output. Also they are very suited for mountain climbing because they provide better illumination intensity in a particular direction.

However, such torches are not particularly suited for area illumination, for example, due to their optical components, the illumination is directed only in a single direction.

Travelers usually need to bring two kinds of lamps, a torch lamp and a camping lamp. Thus, it is highly desirable to de ^¬ sign a kind of illumination system which combines the func- tion of torch and camping lamp. In addition, in other application cases, the users also desire, for example, a table lamp with variable beam angle.

There are several solutions in the prior art to settle the above technical problems. Solution 1 is adding a luminaire to the system to adjust the illumination angle. The solution has the disadvantages of complicated operation and increased device cost.

Solution 2 is installing two different lamps in the same il- lumination device. These two different lamps respectively have narrow and wide beam angles, which is disclosed in US patent 4502102.

Summary of the invention The object of the present invention lies in providing an LED illumination device which can overcome the defects of various solutions in the prior art, and is convenient in adjusting a beam angle of the emergent light. The LED illumination de ^¬ vice according to the present invention can change between directional illumination and large area illumination, and has the advantages of simple operation and low cost.

The present invention proposes an LED illumination device, comprising at least one LED light source, characterized by further comprising a lens and a reflector disposed on a light path of the at least one LED light source, the light source being movable between a first position and a second position which are different positions in the light path di ^¬ rection with respect to the lens and the reflector, wherein at the first position, at lease part of light rays emitted from the at least one light source are adjusted into a light beam with a first beam angle at least by the reflector, and at the second position, the light rays emitted from the at least one light source are adjusted into a light beam with a second beam angle by the lens, and wherein the second beam angle is greater than the first beam angle. According to the present invention, the movability of the light source and the optical assembly comprising of a lens and a reflector collec ^¬ tively realize the change of the beam angle, viz. at the first position of the light source, a relatively smaller beam angle is achieved by at least using the reflector, and at the second position of the light source, a relatively greater beam angle is achieved by using the lens.

Preferably, the LED illumination device further comprising a housing and the light source comprises a first light source mounted at one end of the housing, the reflector is located downstream of the first light source, and the lens is located downstream of the reflector, such that when the illumination device is in use, light rays having different beam angles can be generated at the same side. In such case, preferably, the light rays emitted from the first light source are adjusted to the first beam angle by the reflector and the lens.

According to a preferred solution of the present invention, an outer profile of the lens and an outer profile of the re ^¬ flector are joined together, and the reflector defines a first accommodation cavity for accommodating the light source. Thus, the light source can move between the two ends of the reflector, viz. move between a first end distant from the lens and a second end adjacent to the lens. In addition, the outer profile of the lens and the outer profile of the reflector are joined together, which provides the possibility of distribution of the light rays in various directions, pro ^¬ vides the possibility of broad angle illumination, and im ^¬ proves the aesthetic property of the appearance of the entire LED illumination device.

According to a preferred solution of the present invention, at the first position, the light source is located at the fo ^¬ cal point of the reflector, and the light rays emitted from the light source form parallel light beams after reflected by the reflector, and the parallel light beams are incident upon the lens, and produce the first beam angle by the lens.

Thus, the lens makes a small adjustment to the angle of the parallel light beams, which achieves the first beam angle that is relatively smaller.

Preferably, at the second position, the light source is lo ^¬ cated at the second end of the reflector adjacent to the lens, and the light rays emitted from the light source are incident upon the lens and produce light rays having the sec ^¬ ond beam angle.

Preferably, the shorter the distance between the incident surface and the emergent surface is, the better the effect is. When the distance is short and the light source is at the first position, the lens makes a small change to the beam angle of the output light. The shorter the distance is, the smaller the change made by the lens to the beam angle of the output light is.

According to another preferred alternative embodiment of the present invention, the light source comprises a first light source and a second light source which are located on two sides of the housing, respectively, the reflector is located on a light path of the first light source, and the lens is located on a light path of the second light source. In such case, it is possible to emit light beams having the first beam angle and light beams having the second beam angle from the two ends, and at this time, at the first position, the light beams having the first beam angle are generated only by the reflector, and at the second position, the light beams having the second beam angle are generated only by the lens. In a preferred embodiments, at the first position, the first light source is located at the focal point of the reflector , and the light rays emitted from the first light source form parallel light beams after reflected by the reflector, at the second position, the second light source is located at a po ^¬ sition where the light rays emitted from the second light source are incident upon the lens and produce light beam with the second beam angle.

Preferably, the first beam angle has an angle range of less than 8°, which satisfies the requirements for directional il- lumination.

Preferably, the reflector has a parabolic-shaped profile in cross-section. In the case where the light source is located at the focal point of the reflector, the parabolic-shaped profile is especially helpful to generate the beam angle with the first beam angle which is relatively smaller.

Preferably, the lens has a concave arc-shaped incident sur ^¬ face in cross-section and an emergent surface designed as a free curved surface. When the light source is located at the second position, the concave arc-shaped incident surface is helpful for the receiving of incident light in each direc ^¬ tion, and the incident light travels through the lens and fi ^¬ nally emerges from the emergent surface designed as a free curved surface. The emergent surface which is designed as a free curved surface is used for re-distributing the incident light.

Preferably, at the second position, the light source is lo ^¬ cated at a circle center of the circular arc-shaped incident surface. When the light source is located at the circle cen ^¬ ter, the reflector will substantially have no influence on the light from the light source, and only the lens changes the direction of the light from the light source. Prefera ^¬ bly, the incident surface is in a semi-circular shape.

Preferably, the emergent surface is in rotational symmetry, so as to achieve a symmetrical light distribution pattern. The shape of the emergent surface is configured to produce uniform circular light distribution patterns.

According to a preferred solution of the present invention, the housing comprises a second accommodation cavity having a light emergent opening at at least one end thereof, and an additional auxiliary assembly is provided in the second ac ^¬ commodation cavity.

Preferably, the auxiliary assembly comprises a heat sink, the light source is supported on at least one side of the heat sink, and the movement of the light source is achieved by the movement of the heat sink. The heat sink carries the light source to achieve effective dissipation of the heat generated by the light source. Preferably, the auxiliary assembly fur ^¬ ther comprises a driver a battery, and an electrical connec- tion portion for connecting the driver with the battery, so as to achieve driving of the light source.

Preferably, the driver is a boost converter, a buck converter, or a buck-boost converter.

Preferably, the LED illumination device further comprises a switch manually operable, the housing has a slide groove on a circumferential wall, the switch is connectable with the heat sink by the slide groove and is movable in the slide groove to control the light source to switch between the first posi ^¬ tion and the second position, which makes it easy for a user to manually switch between the two kinds of beam angles.

Preferably, the slide groove is a linear groove opened along a longitudinal axis of the housing. Preferably, the LED il ^¬ lumination device is a dual-purpose lamp for camping and torch . It shall be understood that both the above general descrip ^¬ tion and the following detailed description are for illustrative and explanative purposes in order to provide further de ^¬ scription of the claimed present invention. Brief Description of the Drawings

The accompanying drawings constitute a part of the present Description and are used to provide further understanding of the present invention. Such accompanying drawings illustrate the embodiments of the present invention and are used to de- scribe the principles of the present invention together with the Description. In the accompanying drawings, the same components are represented by the same reference numbers. As shown in the drawings :

Fig. 1 is a schematic diagram of the LED illumination device at the first position according to the first embodiment of the present invention;

Fig. 2 is a schematic diagram of the LED illumination device at the second position according to the first embodiment of the present invention; Fig. 3 is a schematic diagram of the reflector of the LED illumination device according to the first embodiment of the present invention;

Fig. 4 is a schematic diagram of the lens of the LED illumi ^¬ nation device according to the first embodiment of the pre- sent invention; and

Fig. 5 is a schematic diagram of the LED illumination device according to the second embodiment of the present invention. Detailed Description of the Embodiments

Fig. 1 is a schematic diagram of the LED illumination device 100 at the first position according to the first embodiment of the present invention, and Fig. 2 is a schematic diagram of the LED illumination device 100 at the second position ac ^¬ cording to the first embodiment of the present invention. As shown in Figs. 1 and 2, the LED illumination device 100 comprises a housing 14, a light source 6, and an auxiliary as ^¬ sembly for providing electricity power to the light source 6, and the auxiliary assembly and the light source 6 are both within the housing 14. The housing 14 has an opening 15, viz. light output opening, at one end thereof. In order to adjust the light output direction of the light emitted from the light source 6, a lens 11 and a reflector 7 are provided. The lens 11 and the reflector 7 are sequentially provided ad ^¬ jacent to the light output opening, the reflector 7 surround ^¬ ing the light source 6 is disposed downstream of the light source 6 in the light path, and the lens 11 is directly adja ^¬ cent to the reflector 7 and is disposed downstream of the re- flector 7.

As shown from Fig. 1, the light source 6 is located at the first end of the reflector 7 which is distant from the lens 11, viz. at the focal point of the reflector 7 in the figure, such that the light emitted from the light source 6 at the focal point can form parallel light rays after reflected by the reflector 7, and the parallel light rays then are inci ^¬ dent into the lens 11. Due to the short distance between the incident surface and the emergent surface of the lens 11, the lens 11 has very small influence on the angle of the parallel light rays, which keeps the first beam angle of the output light beam less than 8°. In order to achieve the light beam with relatively smaller first beam angle, the reflector 7 has a parabolic shape, as shown in Fig. 3 which is a schematic diagram of the reflector of the LED illumination device according to the first embodiment of the present invention, and it can seen from the figure that the light emitted from the light source at the focal point can form parallel light rays after reflected by the reflector 7. The shorter the distance between the incident surface 12 and the emergent surface 13 of the lens is, the smaller the influence on the first beam angle is. As can be seen from Fig. 2, the light source 6 is located at the second position, viz. the second end of the reflector 7 which is adjacent to the lens 11, the second position is also the center of the concave arc-shaped incident surface 12 of the lens 11, and at this time, the light rays emitted from the light source 6 will no longer be incident upon the re ^¬ flector 7, but are directly incident upon the lens 11. At this time, the reflector 7 has no influence on the final light distribution, as the LED light source 6 only emits light forward. At this time, only the free-form lens 11 works, the beam angle is broad and uniform illuminance can be achieved .

From the above mentioned, the position of the light source 6 has decisive impact on the final beam angle.

As the emergent surface 13 of the lens 11 is a free curved surface, uniform wide light distribution is generated, viz. the relatively greater beam angle is achieved. As shown in Fig. 4 which is a schematic diagram of the lens 11 of the LED illumination device according to the first embodiment of the present invention, the incident surface 12 is a circular arc shape in cross-section, preferably, in a semi-circular shape, that is a spherical surface in three-dimensiona view, pref- ereably, semi-spherical surface and the emergent surface 13 is designed to be rotationally symmetry. The main function of the emergent surface 13 is to get uniform illuminance, for example, illuminance in a circular shape, viz. a bat-wing light distribution curve. The shape of the free-form surface can be calculated using well known algorithms, such as Edge- ray theory, partial differential equation and so on. Refer ^¬ ence can be made to the following articles and books: tai ^¬ lored freeform optical surfaces by Ries H, Muschaweck and nonimaging optics by Narkis Shatz and John C.Bortz. Alterna ^¬ tively, the shape of the free-form surface can be calculated- for example, by considering the flux conservation and snell law, dividing the target circular light spot into N equal partsand determining the points of the profile curve of the free curved surface taking into account the relationship be ^¬ tween input vector, normal vector and output vector. For this, another reference can be made to the document

CN101749641A "deflecting lens with free curved surface for high-power LED street lighting". It shall be pointed out that, if the output beam angles required are 60°, 100°, and 120°, the curves calculated will differ. The range of the second beam angle can be changed according to the users' re ^¬ quirements, and the shape of the lens will be changed corre ^¬ spondingly. The movement of the light source 6 from the first position to the second position is always performed in the first accommo ^¬ dation cavity 16 defined by the reflector 7. In the LED illumination device according to the present invention, such mobility of the light source 6 is achieved by the movement of the heat sink 10 carrying the light source 6. In order to control the movement of the heat sink 10, the LED illumina ^¬ tion device 100 further comprises a switch 1 operable by a hand, the housing 14 has a slide groove 18 on a circumferen- tial wall, the switch 1 is connectable with the heat sink 10 via the slide groove 18 and is movable in the slide groove 18 to control the light source 6 to switch between the first po ^¬ sition and the second position. The slide groove 18 is a linear groove opened along a longitudinal axis of the hous ^¬ ing. Besides the function of controlling the movement of the light source 6, the switch 1 also has the function of turning the illumination device on and off.

The auxiliary assembly is provided in the cavity defined by the housing 14 itself, and the auxiliary assembly further comprises a driver 2 provided on a second side of the heat sink 10, a battery 3, and an electrical connection portion 4 for connecting the driver 2 with the battery 3.

Fig. 5 is a schematic diagram of the LED illumination device according to the second embodiment of the present invention. What is different from the first embodiment of the present invention, the number of the light sources here can be two. The first light source is located at one end of the housing, and the reflector 7 is provided at this end. The other light source, viz. the second light source, is located at the other end of the housing, the lens 11 is located at this end. The reflector 7 is located on the light path of the first light source, and the lens 11 is located on the light path of the second light source. Here, the second accommodation cavity defined by the housing has two light emergent openings , and the auxiliary assembly provided in the accommodation cavity 17 is a little bit different from the auxiliary assembly in the first embodiment In the second embodiment, the driver, battery and an electrical connection portion for connecting the driver with the battery are arranged with a cavity de ^¬ fined by heat sink 10 and the heat sink 10 can support the light source 6 at two sides. The LED illumination device 100 according to the present invention can be designed as a dual-purpose lamp, viz. the dual-purpose lamp for directional illumination and broad an ^¬ gle illumination, for example, the LED illumination device 100 can be designed as a dual-purpose lamp for camping and torch .

The above is merely preferred embodiments of the present in ^¬ vention but not to limit the present invention. For the per ^¬ son skilled in the art, the present invention may have vari- ous alterations and changes. Any alterations, equivalent substitutions, improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

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List of reference signs

100 LED illumination device

1 switch

2 driver

3 battery

4 electrical connection portion

6 light source

7 reflector

10 heat sink

11 lens

12 incident surface

13 emergent surface

14 housing

15 opening

16 first accommodation cavity

17 second accommodation cavity

18 slide groove