WO2013160246A1

WO2013160246A1 - Electronic module and illuminating device comprising the electronic module

Info

Publication number: WO2013160246A1
Application number: PCT/EP2013/058291
Authority: WO
Inventors: Yuanyuan He; Yaojun Feng; Hua Wang; Huiting CHANG
Original assignee: Osram Gmbh
Priority date: 2012-04-23
Filing date: 2013-04-22
Publication date: 2013-10-31
Also published as: CN103378259A

Abstract

The present invention relates to an electronic module (100), comprising a circuit board (1), electronic components (2) arranged on the circuit board (1) and an encapsulation material (3), characterized by further comprising an isolating part at least enclosing the electronic components (2) to isolate the electronic components (2) from the encapsulation material (3). In addition, the present invention further relates to an illuminating device comprising the electronic module.

Description

,

Description

Electronic Module and Illuminating Device Comprising the Electronic Module

Technical Field

The present invention relates to an electronic module and an illuminating device comprising the electronic module

Background Art

An LED module widely used in the illumination technology gen^¬ erally comprises components such as LED chip, circuit board, optical component and electronic component. The LED module with excellent performances should possess waterproof and dustproof functions, for instance, it should meet relevant provisions of IP protection level. In order to conform to such provisions, the following modes are usually used in the prior art: components of an LED module are encapsulated in only one housing, and the LED module is manufactured through processes such as over molding, low pressure molding or potting. In these processes, material such as TPU, PVC, PA, PU or silicon glue is used to encapsulate the LED module. These materials directly cover or encapsulate all components of the LED module when the LED module is manufactured, thus the IP protection level such as IP dustproof and waterproof level is well satisfied.

But the drawback in the prior art should not be neglected, i.e. the material covering or encapsulating the electronic components would have some changes such as "expanding with heat and contracting with cold" under influence of tempera- ture, which damages the electronic components. Especially when the electronic components are fixed on the circuit board through surface mount technology (SMT) , the electronic compo^¬ nents are welded with the circuit board through a lot of sol^¬ der pads preset therefor. A big inner stress will be gener- ated when the encapsulation material, i.e. housing material of the LED module, is deformed under influence of tempera^¬ ture. The stress extrudes or pulls the electronic components and/or solder pads thereof inside the module, resulting in damage of the electronic components and/or solder pads thereof, and further damaging the LED module.

The shortcoming of the above mode lies in posing a risk to security of the electronic components and/or solder pads of the LED module when the IP protection level is met. There^¬ fore, it is urgent to resolve the problems in the prior art. Summary of the Invention

Therefore, one object of the present invention lies in pro^¬ viding an electronic module that can both meet corresponding IP protection level and prevent its electronic components from being damaged by stress inside the module, especially by stress to inside of the module when the encapsulation mate^¬ rial expands with heat and contracts with cold.

The electronic module in accordance with the present inven^¬ tion comprises a circuit board, electronic components ar^¬ ranged on the circuit board and an encapsulation material, characterized by further comprising an isolating part at least enclosing the electronic components to isolate the electronic components from the encapsulation material. The isolating part can enclose, encapsulate or cover the elec^¬ tronic components in a suitable manner, thus forming a pro- tective barrier for protecting the electronic components. An acting force from inside of the electronic module, e.g. stress or strain generated when the encapsulation material expands with heat and contracts with cold, is merely applied on an outer surface of the isolating part and cannot be ap- plied on the electronic components arranged therein. As a re^¬ sult, even if the ambient temperature changes greatly, the electronic components can be in normal operation under pro^¬ tection of the isolating part and is not damaged by deforma^¬ tion of the encapsulation material of the electronic module. In accordance with one preferred embodiment of the present invention, the isolating part is a stress isolating part. The isolating part creates an isolation effect in mechanics ac^¬ cording to the present invention, i.e. the isolating part bears the stress from inside of the electronic module on its own outer surface and does not transfer the stress to the electronic components so as to assure that electronic compo^¬ nents enclosed therein are not affected by the stress. Pref^¬ erably, the isolating part is made from a rigid material. The rigid material is not deformed when extruded or drawn, there- fore, the isolating part made from the rigid material can se^¬ curely and reliably isolate the electronic components from the encapsulation material.

In accordance with one preferred embodiment of the present invention, the isolating part is arranged on the circuit board. Since the electronic components can be preferably mounted on the circuit board through the surface mount tech^¬ nology (SMT) , the isolating part can be directly correspond^¬ ingly mounted on the circuit board so as to targetedly en^¬ close the electronic components to be protected. In accordance with one preferred embodiment of the present invention, the isolating part is configured as a cover com- prising a cavity for accommodating the electronic components. The cavity has a certain depth and can cover, for instance, in a form of cover, over a corresponding region of the circuit board so as to accommodate the electronic components ar- ranged in this region in a space defined by the cover and the circuit board.

In accordance with one preferred embodiment of the present invention, a gap is present between the cover and the elec^¬ tronic components. The gap herein forms a buffer area for as- suring the cover and the electronic components not in contact with each other, further preventing the stress from the encapsulation material from being transferred to the electronic components. Especially when a metal is chosen to manufacture the cover, the gap further can assure electrical insulation between the cover and the electronic components.

In accordance with one preferred embodiment of the present invention, the cover comprises a top wall and a circumferential wall, which define the cavity together, wherein the circumferential wall extends from edges of the top wall, and the cover is in connection with the circuit board through the circumferential wall. Outer surfaces of the top wall and of the circumferential wall of the cover are in contact with the encapsulation material and can bear the stress generated by the encapsulation material inside the electronic module. Since the circumferential wall has a predetermined height, the circumferential wall supported between the top wall and the circuit board can transfer force applied on the top wall to the circuit board. The isolating part configured as cover and the circuit board herein can be fixedly connected by coating glue on an end surface of the circumferential wall in contact with the circuit board or through welding or other suitable processes. In accordance with one preferred embodiment of the present invention, a plurality of projections against the outer sur^¬ faces of the circumferential wall are arranged on the circuit board, and the projections clamp the circumferential wall. By means of the plurality of projections on the circuit board, the cover can be restricted in a corresponding region assigned to the electronic components, thus, positioning be^¬ tween the cover and the circuit board can be simply and con^¬ veniently realized during installation. In accordance with another preferred embodiment of the pre^¬ sent invention, at least one pin is formed on the circumfer^¬ ential wall, and at least one hole is opened on the circuit board. The cover also can be simply restricted at a predeter^¬ mined installation position of the circuit board in a plug-in manner.

In accordance with one preferred embodiment of the present invention, the electronic module further comprises a solder pad arranged in the cavity for joining the electronic compo^¬ nents with the circuit board. Since the security and reli- ability of the solder pad exerts a direct influence on the connection effect between the electronic components and the circuit board, the solder pad also should be protected to prevent it from being damaged by stress inside the electronic module . In accordance with one preferred embodiment of the present invention, the encapsulation material fully covers the iso^¬ lating part. The isolating part herein is advantageously com^¬ pletely arranged inside the encapsulation material, and then it can be assured that the electronic components are not af- fected by stress generated by deformation of the encapsula^¬ tion material in a situation that the electronic module is guaranteed to achieve the industrial IP protection level.

The other object of the present invention is accomplished via an illuminating device comprising the electronic module of the above type. The illuminating device comprises a light en- gine configured as the electronic module and an optical de^¬ vice, wherein the light engine further comprises a light source mounted on the circuit board, and the optical device is configured to enclose the light source. The optical device is, for instance, a lens or the like mounted on the circuit board. The encapsulation material can be used to encapsulate or cover components other than the lens on the circuit board, thus forming a complete illuminating device with good sealing property .

In accordance with one preferred embodiment of the present invention, the light source is an LED chip.

Advantages of the electronic module and the illuminating device comprising the electronic module in accordance with the present invention are as follows: the electronic module has an encapsulation housing achieving the IP protection level, and since a stress isolating part is particularly pro^¬ vided to the electronic components inside the module, even if the external temperature changes prominently, deformation of the encapsulation housing due to influence of temperature does not affect the electronic components inside the module. Such electronic module can be widely used outdoors, espe^¬ cially in bad environment.

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 is a longitudinal sectional view of a first embodiment of an electronic module in accordance with the present inven^¬ tion; Fig. 2 is a longitudinal sectional view of a second embodi^¬ ment of an electronic module in accordance with the present invention; and

Fig. 3 is a schematic diagram of an illuminating device in accordance with the present invention. 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 may be practiced. In this regard, direc- tional terminology, such as "inner", "outer", "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 may be utilized and structural or logical changes may made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

It is to be understood that the features of the various exem^¬ plary embodiments described herein may be combined with each other, unless specifically noted otherwise.

Fig. 1 shows a longitudinal sectional view of a first embodi^¬ ment of an electronic module 100 in accordance with the pre^¬ sent invention. The electronic module 100 comprises a circuit board 1, electronic components 2 arranged on the circuit board 1 and an encapsulation material 3. The encapsulation material 3 partially covers an upper surface of the circuit board 1 shown in Fig. 1 so as to completely encapsulate the electronic components 2 in the encapsulation material 3, thus enabling the electronic module 100 to achieve the dustproof and waterproof IP protection level. The electronic components 2 can be resistors, capacitors or the like.

Since the encapsulation material 3 is made from a nonrigid material such as TPU, PVC, PA, PU or silicon glue, the encap^¬ sulation material 3 is deformed, i.e. expanding with heat and contracting with cold, when temperature changes greatly in the environment where the electronic module 100 is located. Such deformation generates a pulling stress or compressive stress inside the electronic module 100. Once the stress acts on the electronic components 2 or on joint where the elec- tronic components 2 and the circuit board 1 are connected, i.e. solder pad 10, the electronic components 2 or the solder pad 10 is damaged, thus causing malfunction of the electronic module 100. Therefore, the isolating part is particularly provided between the electronic components 2 and the encapsu- lation material 3 to isolate the stress inside the electronic module 100 from the electronic components 2. The isolating _

y

part preferably is made from a rigid material such as hard plastic or metal, then, it will not be deformed when bearing a pressure.

As shown in Fig. 1, the isolating part can be configured as cover 4 comprising a top wall 5 and a circumferential wall 6 that extends from edges of the top wall 5, thus defining a cavity R. In order to protect the electronic components 2 with the cover, the cover 4 covers a region of the circuit board 1 carrying the electronic components 2, thus allowing the electronic components 3 and the solder pad 10 for fixing the electronic components 3 on the circuit board 1 in the cavity R. The encapsulation material 3 completely covers the cover 4, and compressive stress or pulling stress generated by deformation of the encapsulation material 3 as shown by arrows in Fig. 1 is directly applied on outer surfaces of the top wall 5 and of the circumferential wall 6. Since a gap is present between the electronic components 2 and the solder pad 10 accommodated in the cavity R and the outer surfaces of the top wall 5 and of the circumferential wall 6, it is as- sured not to transfer the compressive stress or the pulling stress to the electronic components 2. The cover 4 forms a protective barrier resisting the compressive stress or the pulling stress for the electronic components 3 of the elec^¬ tronic module 100. In order to assure that the cover 4 can be mounted on the circuit board 1 at a fixed position, two pins 8 are particu^¬ larly formed on ends surfaces of the circumferential wall 6 for connection with the circuit board 1, and two holes 9 are correspondingly opened on the circuit board. Positioning be- tween the cover 4 and the circuit board 1 is facilitated in a plug-in manner, and the end surface where the pins 8 are lo^¬ cated is fixed with the circuit board 1 in a suitable manner such as welding and bonding.

Fig. 2 is a longitudinal sectional view of a second embodi^¬ ment of an electronic module 100 in accordance with the pre^¬ sent invention. The difference between the second embodiment and the first embodiment lies in that in order to assure that the cover 4 can be mounted on the circuit board 1 at a fixed position, a plurality of projections 7 also can be formed on the circuit board 1. These projections 7, through circumfer^¬ ential surfaces thereof, are against outer surfaces of the circumferential wall 6, thus positioning between the cover 4 and the circuit board 1 can be realized in a clamp manner.

In a third embodiment not shown, numbers of the pins 8 and corresponding holes 9 for positioning the cover 4 and the circuit board 1 in the plug-in manner as shown in Fig. 1 can be one or no less than two, respectively.

In a preferred embodiment not shown, the isolating part can have other profiles suitable for covering or enclosing the electronic components 2, and can be in mechanical connection with the circuit board 1 in other suitable connecting manner or structure.

Fig. 3 is a schematic diagram of an illuminating device 200 in accordance with the present invention. The illuminating device 200 comprises an optical device 201 configured as a lens and the electronic module 100 as a light engine, wherein in order to show the cover 4 clearly, the encapsulation material 3 encapsulating the circuit board 1 and the electronic components is not shown in Fig. 3. A light source configured as LED chip, for example, is mounted on the circuit board 1, and the optical device 201 is arranged on the light source. The cover 4 arranged on the circuit board 1 is configured to cover the electronic components 3 (not shown) in the light engine to be protected so as to prevent the electronic compo^¬ nents 3 from being damaged by pulling stress or compressive stress of the illuminating device 200, especially inside the electronic module 100.

In addition, while a particular feature or aspect of an embodiment of the invention may have been disclosed with re^¬ spect to only one of several implementations, such feature or aspect may be combined with one or more other features or as- pects of the other implementations for any given or particu^¬ lar application. Furthermore, to the extent that the terms "include", "have", "with", or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise".

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 sub- stitutions, improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

List of reference signs

1 circuit board

2 electronic component

3 encapsulation material

4 cover

5 top wall

6 circumferential wall

7 projection

8 pin

9 hole

10 solder pad

100 electronic module

200 illuminating device

201 optical device

Claims

Patent claims

1. An electronic module (100), comprising a circuit board (1), electronic components (2) arranged on the circuit board (1) and an encapsulation material (3), characterized by fur^¬ ther comprising an isolating part at least enclosing the electronic components (2) to isolate the electronic compo^¬ nents (2) from the encapsulation material (3) .

2. The electronic module (100) according to Claim 1, char- acterized in that the isolating part is a stress isolating part .

3. The electronic module (100) according to Claim 1, char^¬ acterized in that the isolating part is arranged on the cir^¬ cuit board ( 1 ) .

4. The electronic module (100) according to any of Claims 1-3, characterized in that the isolating part is configured as a cover (4) comprising a cavity (R) for accommodating the electronic components (2).

5. The electronic module (100) according to Claim 4, char- acterized in that a gap is present between the cover (4) and the electronic components (2) .

6. The electronic module (100) according to Claim 4, char^¬ acterized in that the cover (4) comprises a top wall (5) and a circumferential wall (6), which define the cavity together, wherein the circumferential wall (6) extends from edges of the top wall (5), and the cover (4) is in connection with the circuit board (1) through the circumferential wall (6) .

7. The electronic module (100) according to Claim 6, char- acterized in that a plurality of projections (7) against outer surfaces of the circumferential wall (6) are arranged on the circuit board (1), and the projections (7) clamp the circumferential wall (6) .

8. The electronic module (100) according to Claim 6, char^¬ acterized in that at least one pin (8) is formed on the circumferential wall (6), and at least one hole (9) is opened on the circuit board (1) .

9. The electronic module (100) according to Claim 4, char- acterized by further comprising a solder pad (10) arranged in the cavity (R) for joining the electronic components (2) with the circuit board (1) .

10. The electronic module (100) according to any of Claims 1-3, characterized in that the isolating part is made from a rigid material.

11. The electronic module (100) according to any of Claims 1-3, characterized in that the encapsulation material (3) fully covers the isolating part.

12. An illuminating device (200) comprising a light engine and an optical device (201), characterized in that the light engine is the electronic module (100) according to any of Claims 1-11, the light engine further comprises a light source mounted on the circuit board (1), and the optical de^¬ vice (201) is configured to enclose the light source.

13. The illuminating device (200) according to Claim characterized in that the light source is an LED chip.