Illuminating Device Technical Field

The present invention relates to an illuminating device. Background Art

Because of relative high efficiency, long service life and low power consumption, LED light sources are more and more welcomed by the people. There are a large number of LED ret ^¬ rofit lamps in the current market. A LED retrofit lamp gener ^¬ ally has a heat sink, a circuit board arranged in the heat sink and a lens arranged at the light emergent opening of the heat sink, wherein a LED chip is arranged on the circuit board, and the lens is capable of processing light rays of the LED chip, to fulfill different illuminating effects. How ^¬ ever, in the prior art, there is generally need to fix the circuit board on the heat sink through bolts, and to fix the lens at the light emergent opening of the heat sink by means of additional bolts and possible accessories or by means of

UV glue, double sided adhesive. It is obvious that the opera ^¬ tion of the above mentioned method is relative complex and has relative high cost. Moreover, the connection reliability between the lens and the heat sink is also relative low. Summary of the Invention

In order to solve the above mentioned problem, the present invention provides an illuminating device, which has a few components, low cost and is easy to be assembled. Further ^¬ more, after a long running time of the illuminating device according to the present invention, each component of the il ^¬ luminating device still has relative high connection reli ^¬ ability.

The object of the present invention is achieved through an illuminating device in such a manner, viz. the illuminating device comprises a heat sink having a bottom wall and a circumferential wall extending from the bottom wall, defining an accommodating cavity; a lens arranged at an opening of the accommodating cavity; and a circuit board having a light source and being arranged on the bottom wall, wherein the lens includes at least one snap-fit structure and at least one pressing portion, and the snap-fit structure snaps into the circumferential wall to fix the lens to the heat sink and the lens presses the circuit board against the bottom wall through the pressing portion. In an embodiment of the present invention, the lens can be directly snapped at the heat sink through the snap-fit structure, without additional mechanical structures, such as bolt and hold shield etc. It signifi ^¬ cantly reduces the amount of components of the illuminating device and decreases assembly difficulty. Moreover, the pressing portion formed on the lens simultaneously presses the circuit board against the heat sink, while the lens is snapped at the heat sink. Thus, there is no need to sepa ^¬ rately fix the circuit board on the heat sink, which has spe- cial significance for the circuit board configured as ceramic circuit board. The reason lies in: ceramic circuit boards are friable, because of their material characteristics; when fix ^¬ ing the same on the heat sink through bolts, there is a chance to damage them, while the concept of the present in- vention abandons mechanical structures easily damaging cir ^¬ cuit boards.

It is preferable that the lens comprises a baseplate and at least one micro-lens structure formed on the baseplate. The micro-lens structure is more suitable for matching with a light source. Furthermore, in a situation that the illuminat ^¬ ing device has a plurality of light sources, a micro-lens structure is individually equipped for each light source, which is advantageous for individually adjusting light rays of a light source.

According to a preferable embodiment of the present inven ^¬ tion, it is provided that there is no need to additionally arrange an individual component, when configuring the micro- lens structure as the pressing portion. It reduces to a large extent the structural complexity of the lens and decreases the production cost.

According to another preferable embodiment of the present in- vention, it is provided that the lens further includes at least one positioning column formed on the baseplate, and the positioning column is configured as the pressing portion. It is advantageous that at least one through hole for insertion of the positioning column is formed on the circuit board. The positioning column can help with accurate alignment of the lens and a light source on the circuit board. It has practi ^¬ cal significance particularly for the situation that the il ^¬ luminating device has a plurality of light sources and a plu ^¬ rality of micro-lens structures. Furthermore, instead of mi- cro-lens structure, the positioning column is used as the pressing portion, which reduces to a large extent design difficulty of the micro-lens structure.

It is further preferable that the positioning column includes a first section capable of being inserted into the through hole and a second section, wherein a connecting part of the first section and the second section forms a stop step, which presses against the circuit board. In an assembled state of the illuminating device, said stop step reliably presses the circuit board against the heat sink.

According to an embodiment of the present invention, it is provided that the illuminating device further comprises a bi ^¬ asing device arranged between the lens and the circuit board, which is used to provide a bias force between the lens and the circuit board. After mounting the lens on the heat sink, the spring is extruded and is in a forced state. After a long running time of the illuminating device, the lens or the heat sink might be deformed because of aging. However, the lens is supported on the heat sink in the form of a prestress. Thus, even if the components are deformed, the lens would also be reliably fixed on the heat sink without loosening. It is preferable that the biasing device includes at least one spring and at least one insulation washer, wherein one end of the spring bears against the lens, and the other end bears against the circuit board through the insulation washer. The insulation washer is insulated from the spring and the circuit board, which avoids short circuit of the cir ^¬ cuit board.

It is advantageous that the spring is nested onto the press ^¬ ing portion. The pressing portion is capable of being used as guiding element of the spring, so as to avoid undesired dis- placement of the spring.

It is further advantageous that the spring is a spiral spring. Certainly, the spring can also be a spring of another type, for example plate spring.

According to a preferable embodiment of the present inven- tion, it is provided that the snap-fit structure is config ^¬ ured as elastic hook. Preferably, a projection is formed on the circumferential wall, and the elastic hook engages with the projection. The snap-fit structure of such type has a simple structure and easy manufacture. During practical as ^¬ sembly process, it only needs to insert the lens into the opening of the accommodating cavity, while the elastic hook is easy to engage with the projection, wherein the operation is simple and the connection is very tight. It is advantageous that the heat sink further includes at least one fin, which radially extends on outer side of the circumferential wall. The fin significantly increases contact area of the heat sink with air of the environment, which im ^¬ proves radiating property of the heat sink. It is preferable that an embedding groove is formed in the bottom wall, and the circuit board is arranged in the embed ^¬ ding groove in a form fitting manner. The circuit board is therefore firmly held in the embedding groove, which prevents undesired movement of the circuit board. If a thermal interface material is arranged between the cir ^¬ cuit board and the bottom surface of the embedding groove, it would be very advantageous for the cooling of the circuit board .

It is preferable that the circuit board is a ceramic circuit board, which has good thermal conductivity. Certainly, the circuit board can also be a circuit board of another type, metal core circuit board for instance.

It is preferable that the light source is a LED light source, which has advantages of long service lift, high luminous ef- ficiency and environmental protection.

It is to be understood that the features of the various exem ^¬ plary embodiments described herein might be combined with each other, unless specifically noted otherwise. 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 compo ^¬ nents are represented by the same reference numbers. As shown in the drawings :

Fig. 1 composed schematic diagram of a first example of the illuminating device according to the present invention;

Fig. 2 composed schematic diagram of a second example of the illuminating device according to the present invention; and Fig. 3 sectional view of the illuminating device in an assembled state according to the first example as shown in Fig. 1.

Detailed Description of the Embodiments

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention might be practiced. In this regard, di ^¬ rectional terminology, such as "top", "bottom", "upper", "lower", is used in reference to the orientation of the fig ^¬ ures being described. Because components of embodiments of the present invention can be positioned in a number of dif ^¬ ferent orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments might be utilized and structural or logical changes might be made without departing from the scope of the present invention. The following de ^¬ tailed description, therefore, is not to be taken in a limit ^¬ ing sense, and the scope of the present invention is defined by the appended claims.

Fig. 1 shows a composed schematic diagram of the first exam- pie of the illuminating device 100 according to the present invention. As shown in the figure, the illuminating device 100 according to the present invention comprises: a heat sink 1 having a bottom wall 111 and a circumferential wall 112 ex ^¬ tending from the bottom wall 111, defining an accommodating cavity 11; a lens 2 arranged at an opening of the accommodat ^¬ ing cavity 11 in the assembled state of the illuminating de ^¬ vice 100 (see Fig. 3); and a circuit board 3 having a light source, wherein the circuit board 3 is arranged on the bottom wall 111 in the assembled state of the illuminating device 100. In the embodiment of the present invention, the circuit board 3 is a ceramic circuit board, and it can also be a cir ^¬ cuit board of another type, such as metal core circuit board etc. In addition, the light source arranged on the circuit board 3 is a LED light source 7. Furthermore, the heat sink 1 further includes at least one fin 12, which radially extends on outer side of the circumferential wall 112. In the present example, an embedding groove 114 is formed in the bottom wall 111, and the circuit board 3 is arranged in the embedding groove 114 in a form fitting manner. In a preferable example, a thermal interface material 6 is arranged between the cir ^¬ cuit board 3 and the bottom surface of the embedding groove 114 (see Fig. 3) . Moreover, it can further be seen from the figure that the lens 2 includes a baseplate 21 and a micro-lens structure 22 formed on the baseplate 21. In the present example, only one LED light source 7 is arranged on the circuit board 3. Thus, only one micro-lens structure 22 is formed on the baseplate 21, wherein the micro-lens structure 22 is configured as pressing portion, which presses against the circuit board 3 by means of its free end. Furthermore, the lens 2 further in ^¬ cludes at least one elastic hook 24 configured as snap-fit structure. In the assembled state of the illuminating device 100, the elastic hook 24 snaps into a projection 113 formed on the circumferential wall 112 to fix the lens 2 to the heat sink 1 , and the micro-lens structure 22 presses the circuit board 3 against the bottom surface of the embedding groove 114. In addition, it can be observed from Fig. 1 that the illuminating device 100 further comprises a biasing device between the lens 2 and the circuit board 3, which is used to provide a bias force between the lens 2 and the circuit board 3. In the present example, the biasing structure includes a spring 4 configured as spiral spring and an insulation washer 5. The spring 4 is nested onto the micro-lens structure 22, wherein one end of the spring 4 bears against the baseplate 21 of the lens 2, while the other end bears against the circuit board 3 through the insulation washer 5. Fig. 2 shows a composed schematic diagram of the second exam ^¬ ple of the illuminating device 100 according to the present invention. The heat sink 1 of the illuminating device 100 in the second example has the same structure as that of the il ^¬ luminating device 100 in the first example, thus, it is not described here. The differences between the illuminating de- vices of the two examples lie in the amount of the LED light sources 7 on the circuit board 3 and the structure of the lens 2.

It can be seen from Fig. 2 that a plurality of LED light sources 7 are arranged on the circuit board 3; in the present example, 4 LED light sources 7 are arranged. Thus, the struc ^¬ ture of the lens 2 is correspondingly adjusted. It can be seen from the figure that 4 micro-lens structures 22 are formed on the baseplate 21 of the lens 2, viz. each LED light source 7 is equipped with one micro-lens structure 22. How- ever, another important difference between the illuminating device 100 in the second example and that in the first exam ^¬ ple lies in that the micro-lens structures 22 are not used as pressing portion any more. Instead of that, a plurality of positioning columns 23 are formed on the baseplate 21 of the lens 2, which are used as pressing portion. For this purpose, through holes 31 for insertion of the positioning columns are also formed on the circuit board 3. In the present example, two positioning columns 23 are arranged and two through holes 31 are therefore opened on the circuit board 23. Furthermore, it can further be seen from Fig. 2 that the po ^¬ sitioning column 23 includes a first section 231 capable of being inserted into the through hole 31 and a second section 232, wherein a connecting part of the first section 231 and the second section 232 forms a stop step 233, which presses against the circuit board 3.

In addition, in the second example as shown in Fig. 2, the illuminating device 100 also has a biasing device arranged between the lens 2 and the circuit board 3. In the present example, the biasing device includes tow springs 4, which are nested onto the positioning columns 23, instead of being nested onto the micro-lens structures 22. Moreover, the bias ^¬ ing device in the second example fails to include an insula ^¬ tion washer 5. However, an insulation washer 5 can also be additionally arranged between the spring 4 and the circuit board 3. Fig. 3 shows a sectional view of the illuminating device 100 in an assembled state in accordance with the first example as shown in Fig. 1. It can be seen from the figure that the elastic hook 24 of the lens 2 engages with the projection 113 formed on the circumferential wall 112 of the accommodating cavity 11 of the heat sink 1, and the micro-lens structure 22 of the lens 2 presses the circuit board 3 against the bottom surface of the embedding groove 114. The spring 4 nested onto the micro-lens structure 22 is compressed between the base ^¬ plate 21 and the insulation washer 5 arranged on the circuit board 3, so that the spring 4 is in a forced state. After a long running time of the illuminating device 100, the lens 2 or the heat sink 1 might be deformed because of aging. How ^¬ ever, the lens 2 is supported on the heat sink 1 in the form of a prestress. Thus, even if the components are deformed, the lens 2 would also be reliably fixed on the heat sink without loosening.

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 might have va- rious 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

1 heat sink

11 accommodating cavity 111 bottom wall

112 circumferential wall

113 projection

114 embedding groove

12 fin

2 lens

21 baseplate

22 micro-lens structure

23 positioning column

231 first section

232 second section

233 stop step

24 elastic hook

3 circuit board

31 through hole spring

insulation washer

thermal interface material

LED light source

illuminating device