WO2013178594A1

WO2013178594A1 - Backlight module, backlight module chain, and light box comprising the backlight module chain

Info

Publication number: WO2013178594A1
Application number: PCT/EP2013/060891
Authority: WO
Inventors: Yaojun Feng; Canbang Yang; Yuanyuan He; Hua Wang
Original assignee: Osram Gmbh
Priority date: 2012-05-28
Filing date: 2013-05-27
Publication date: 2013-12-05
Also published as: CN103453382A

Abstract

The present invention relates to a backlight module (100), comprising at least one light-emitting assembly (1), wherein, the backlight module (100) further comprises a light guide plate (2) disposed downstream the light-emitting assemblies (1) on a light path, and a reflector (3) disposed on a side of the light guide plate (2), wherein light of the light-emitting assemblies (1) enter into the light guide plate (2), a portion of the light emerges from a light emergent side of the light guide plate (2), and another portion of the light, which emits to the reflector (3) through the light guide plate (2), is reflected back to the light guide plate (2) by the reflector (3), and emerges from the light emergent side of the light guide plate (2). In addition, the present invention also relates to a backlight module chain (200) comprised of at least two backlight modules (100) of the above type, and a light box (300) comprising at least one backlight module chain (200).

Description

Backlight Module, Backlight Module Chain, and Light Box

Comprising the Backlight Module Chain

Technical Field

The present invention relates to a backlight module for a light box. In addition, the present invention also relates to a backlight module chain comprised of the backlight modules, and a light box comprising the backlight module chain.

Background Art

For the purpose of publicity, people usually use light boxes to attract the attention of the target population. The tradi^¬ tional light boxes generally employ fluorescent tubes as backlights. With the continuous development of the LED tech^¬ nology, more and more people are willing to use LEDs instead of various illumination devices. This is because LED illumi^¬ nation has irreplaceable advantages, such as energy saving, very low power consumption, and electrical-to-optical conver- sion efficiency near to 100%. It can save more than 80% en^¬ ergy compared with the traditional light source with the same illuminating efficiency and has a longer service life. In view of the above advantages, LEDs are more and more fre^¬ quently used as light sources, for example, a lot of LED ret- rofit lamps in the market. Therefore, many manufacturers use LEDs, instead of traditional fluorescent tubes, as the light sources of the light boxes.

Due to the characteristics of the LED itself, the light dis^¬ tribution is Lambertian, which, however, cannot meet the ba- sic requirements of illumination of the light box. Thus, it is required to equip the LED with a lens so as to adjust the light distribution. With a lens, the light distribution is wider, and in many cases, the light is in bat-wing distribu^¬ tion. By using a lens, the thickness of the light box employ- ing an LED as a backlight can be reduced to a certain extent. However, the effect of the lens is limited. The thickness of the light box is still large, usually 0.5 to 2 times as large as the pitch between two LEDs .

Summary of the invention In order to solve the above technical problem, the present invention provides a backlight module for a light box. The backlight module has good light distribution, and is allowed to be installed in a light box with a small thickness without affecting the illumination of the light box. Furthermore, the present invention also provides a backlight module chain com^¬ prised of the backlight modules, and a light box comprising the backlight module chain. The light box according to the present invention has superior illumination effect while having a smaller thickness. The first object of the present invention is realized by a backlight module. The backlight module comprises at least one light-emitting assembly, and the backlight module further comprises a light guide plate disposed downstream the light- emitting assemblies on a light path, and a reflector disposed on a side of the light guide plate, wherein light of the light-emitting assemblies enter into the light guide plate, a portion of the light emerges from a light emergent side of the light guide plate, and another portion of the light, which emits to the reflector through the light guide plate, is reflected back to the light guide plate by the reflector, and emerges from the light emergent side of the light guide plate. In the design solution of the present invention, the backlight module is a relatively small light-emitting unit, and can use a light guide plate having a relatively small size, which greatly reduces the cost of the backlight module according to the present invention. Further, the backlight module employing the light guide plate can achieve approxi^¬ mately the same or better light distribution effect, compared with a backlight module in the prior art which employs an or^¬ dinary lens. In addition, the reflector disposed on a side of the light guide plate reflects a portion of the light, which cannot directly emerge from the light emergent side, back to the light guide plate, and then the light emerges from the light emergent side, which significantly improves the lumi^¬ nous efficiency of the backlight module, and reduces light loss.

According to a preferred design solution of the present invention, the light guide plate comprises a first end surface and a second end surface opposite each other, and the light of the light-emitting assembly enter into the light guide plate through the first end surface and/or the second end surface. The light of the light-emitting assembly emitted through the light guide plate becomes more uniform. At same time, this arrangement allows the backlight module according to the present invention to have a structure with a rela- tively small thickness.

Preferably, the light guide plate comprises a first side sur^¬ face between the first end surface and the second end sur^¬ face, and the reflector is disposed over the first side sur^¬ face. The light guide plate in the design solution of the present invention is a flat structure, for example, a hexahe- dral structure, wherein one of two opposite side surfaces having a large area can serve as the first side surface, the reflector can be arranged over the first side surface. Here, the reflector actually can be directly attached to the first side surface, or can be disposed a predetermined space away from the first side surface. Further preferably, the light guide plate further comprises a second side surface disposed opposite the first side surface, and the second side surface is the light emergent side. In the design solution of the present invention, a portion of the light from the light-emitting assemblies directly emerges from the second side surface, and another portion of the light reflected back by the reflector also emerges from the second side surface.

Advantageously, the backlight module further comprises a first diffusion sheet disposed on the second side surface. In the design solution of the present invention, the light emerging from the second side surface can not necessarily meet some special requirements of illumination, thus, an ad^¬ ditional diffusion sheet is disposed on the second side sur^¬ face to adjust the emergent light. Advantageously, the reflector is disposed directly on the first side surface. In a preferred design solution of the present invention, the reflector can be designed as a reflec^¬ tive film, which thereby can directly adhere to the first side surface. This avoids as much as possible light leakage from the gap between the reflector and the first side sur^¬ face .

Further advantageously, the light-emitting assembly is dis^¬ posed directly on the first end surface and/or the second end surface. The light from the light-emitting assembly can di- rectly enter the light guide plate through the first end sur- face and/or the second end surface, which thereby prevents light leakage from the gaps between the light-emitting assemblies and the first and/or second end surfaces.

Preferably, the reflector at least covers the first side sur- face. As the reflector completely covers the first side sur^¬ face, all the light emitted to the first side surface can be reflected by the reflector, and emerges from the second side surface .

Advantageously, the reflector is designed as a reflective film or a flat reflective sheet.

Preferably, the light guide plate is designed as a cuboid, and the first side surface constitutes one surface of the cu^¬ boid, wherein the length of a long side of the first side surface is smaller than 5 inches. The light guide plate hav- ing a small size has a low cost and is easy to manufacture.

Preferably, the backlight module according to the present in^¬ vention comprises at least two light-emitting assemblies. The light-emitting assemblies are arranged, in a manner of facing one another, on the two opposite end surfaces of the light guide plate, such that the light-emitting assemblies emit light towards each other, which allows the backlight module according to the present invention to output more uniform light .

Preferably, the light-emitting assemblies are designed as LED light-emitting assemblies. The LED light-emitting assemblies have the advantages of long life, high luminous efficiency, and environmental protection.

Another object of the present invention is achieved by backlight module chain, wherein the backlight module chain comprises at least two backlight modules of the above type.

Preferably, the backlight modules in the backlight module chain are connected in parallel with each other, such that when the backlight module chain is driven by a constant volt^¬ age source, the backlight length can be cut arbitrarily, for example, each backlight module chain has three, four, or other numbers of backlight modules, but the driving voltage of each backlight module remains unchanged. The last object of the present invention is achieved by a light box comprising at least one backlight module chain of the above type. The light box in accordance with the present invention can have a smaller thickness than the light box in the prior art, when employing the backlight module chain of the above type.

Preferably, the light box further comprises a second diffu^¬ sion sheet disposed on a light emergent opening of the light box. The second diffusion sheet can further adjust the light from the backlight module chain so as to meet the special re- quirements of the illumination of the light box.

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 repre^¬ sented by the same reference sign. In the drawings,

Fig. 1 is a schematic diagram of the backlight module accord- ing to the first embodiment of the present invention;

Fig. 2 is a schematic diagram of the backlight module accord^¬ ing to the second embodiment of the present invention;

Fig. 3 is a schematic diagram of the backlight module chain according to the present invention; and

Fig. 4 is a schematic diagram of the light box according to 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 "top", "bottom", "front", "back", "on", "below" "side surface" etc., is used with reference to the orientation of the Figure (s) being described. Because components of embodiments can be positioned in a number of different 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 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 is a schematic diagram of the backlight module 100 ac^¬ cording to the first embodiment of the present invention. As can be seen from the figure, the backlight module 100 com^¬ prises a plurality of light-emitting assemblies 1, a light guide plate 2 disposed downstream the light-emitting assemblies 1 on a light path, and a reflector 3 disposed on a side of the light guide plate 2, wherein light of the light- emitting assemblies 1 enter into the light guide plate 2, and the reflector 3 reflects the light, which emits to the re^¬ flector 3 through the light guide plate 2, through the light guide plate 2. In the embodiment of the present invention, the light guide plate 2 is designed as a cuboid, and com^¬ prises a first end surface 21 and a second end surface 22 op- posite each other, and the light of the light-emitting assemblies 1 enter into the light guide plate 2 through the first end surface 21 and the second end surface 22, respectively. The first side surface 23 constitutes one surface of the cu^¬ boid, wherein the length of a long side of the first side surface 23 is smaller than 5 inches. The reflector 3 designed as a reflective film or a flat reflective sheet is disposed on the first side surface 23, and the reflector 3 covers and extends over the first side surface 23. According to the de^¬ sign solution of the present invention, the backlight module 100 could also comprise only one light-emitting assembly 1, the light of the light-emitting assembly 1 enter into the light guide plate 2 through the first end surface 21 or the second end surface 22.

In the embodiment of the present invention, the reflector 3 can be directly disposed on the first side surface 23, or can be disposed a predetermined space away from the first side surface 23. In addition, in the embodiment of the present in^¬ vention, the light-emitting assemblies 1 are designed as LED light-emitting assemblies. In the schematic diagram of Fig. 1, only the two LED light-emitting assemblies disposed oppo^¬ site each other on the first end surface 21 and the second end surface 22 can be seen. However, in practical applica^¬ tions, more pairs of LED light-emitting assemblies can be used .

Fig. 2 is a schematic diagram of the backlight module 100 ac^¬ cording to the second embodiment of the present invention. The only difference between the backlight module 100 in the second embodiment as shown in Fig. 2 and the backlight module 100 in the first embodiment as shown in Fig. 1 lies in: a first diffusion sheet 4 is disposed on the second side sur^¬ face 24 which is disposed opposite the first side surface 23, the first diffusion sheet 4 being capable of further adjust- ing the emergent light so as to meet some special require^¬ ments of the illumination.

In the two embodiments shown in Fig. 1 and Fig. 2, the light from the LED light-emitting assemblies enter into the light guide plate 2 through the first end surface 21 and the second end surface 22, wherein a portion of the light directly emerges from the second side surface 24, viz. the light emer^¬ gent surface, of the light guide plate, and another portion of the light emits to the first side surface 23 opposite the second side surface 24. In order to prevent light leakage from the first side surface, the reflector 3 disposed on the first side surface 23 reflects, in the direction of the sec^¬ ond side surface 24, the another portion of the light back to the light guide plate 2, and then the light emerges from the light emergent side. Fig. 3 is a schematic diagram of the backlight module chain 200 according to the present invention. As can be seen from the figure, the backlight module chain 200 comprises a plu^¬ rality of backlight modules 100 in serial connection. How^¬ ever, according to a preferred design solution of the present invention, these backlight modules 100 can also be in paral^¬ lel connection with each other, and can be driven by a con- ₁

stant voltage source. Thus, the backlight module chains 200 comprising different numbers of backlight modules 100 can be used according to the requirements, but the backlight modules 100 in each backlight module chain 200 have the same driving voltage.

Fig. 4 is a schematic diagram of the light box 300 according to the present invention. As can be seen from the figure, the bottom of the light box 300 according to the present inven^¬ tion is provided with one backlight module chain 200. How^¬ ever, the number of the backlight module chain 200 in the light box 300 is not limited to one, and multiple backlight module chains 200 can be disposed in the light box 300. In addition, as can be further seen from the figure, a second diffusion sheet 5 is disposed on a light emergent opening of the light box 300. The second diffusion sheet 5 can further adjust the light from the backlight module chain 200 so as to meet some special requirements of the illumination of the light box. For example, the second diffusion sheet 5 can be designed as a frosted sheet, such that people could hardly see the internal structure of the light box 300 from the out^¬ side .

Further, as can be seen from the figure, after using the backlight module 100 and the backlight module chain 200 ac^¬ cording to the present invention, the thickness of the light box is obviously reduced.

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. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and de^¬ scribed without departing from the scope of the present in^¬ vention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be lim^¬ ited only by the claims and the equivalents thereof.

, ^

List of reference signs

1 light-emitting assembly

2 light guide plate

21 first end surface

22 second end surface

23 first side surface

24 second side surface

3 reflector

4 first diffusion sheet 5 second diffusion sheet

100 backlight module

200 backlight module chain

300 light box

Claims

1. A backlight module (100), comprising at least one light- emitting assembly (1), characterized in that, the backlight module (100) further comprises: a light guide plate (2) dis^¬ posed downstream the light-emitting assemblies (1) on a light path; and a reflector (3) disposed on a side of the light guide plate (2), wherein light of the light-emitting assemblies (1) enter into the light guide plate (2), a portion of the light emerges from a light emergent side of the light guide plate (2), and another portion of the light, which emits to the reflector (3) through the light guide plate (2), is reflected back into the light guide plate (2) by the re^¬ flector (3) , and emerges from the light emergent side of the light guide plate (2) .

2. The backlight module (100) according to Claim 1, charac^¬ terized in that, the light guide plate (2) comprises a first end surface (21) and a second end surface (22) opposite each other, and the light of the light-emitting assembly (1) enter into the light guide plate (2) through the first end surface (21) and/or the second end surface (22) .

3. The backlight module (100) according to Claim 2, charac^¬ terized in that, the light guide plate (2) comprises a first side surface (23) between the first end surface (21) and the second end surface (22), and the reflector (3) is disposed over the first side surface (23) .

4. The backlight module (100) according to Claim 3, charac^¬ terized in that, the light guide plate (2) further comprises a second side surface (24) disposed opposite the first side surface (23), and the second side surface (24) is the light emergent side.

5. The backlight module (100) according to Claim 4, charac^¬ terized in that, the backlight module (100) further comprises a first diffusion sheet (4) disposed on the second side sur^¬ face (24) .

6. The backlight module (100) according to any of Claims 2- 5, characterized in that, the reflector (3) is disposed di^¬ rectly on the first side surface (23) .

7. The backlight module (100) according to any of Claims 2- 5, characterized in that, the light-emitting assembly (1) is disposed directly on the first end surface (21) and/or the second end surface (22) .

8. The backlight module (100) according to any of Claims 2- 5, characterized in that, the reflector (3) at least covers the first side surface (23) .

9. The backlight module (100) according to any of Claims 2- 5, characterized in that, the reflector (3) is designed as a reflective film or a flat reflective sheet.

10. The backlight module (100) according to any of Claims 2- 5, characterized in that, the light guide plate (2) is de- signed as a cuboid, and the first side surface (23) consti^¬ tutes one surface of the cuboid, wherein the length of a long side of the first side surface (23) is smaller than 5 inches.

11. The backlight module (100) according to any of Claims 1- 5, characterized in that, the backlight module (100) com- prises at least two light-emitting assemblies (1) .

12. The backlight module (100) according to any of Claims 1- 5, characterized in that, the light-emitting assemblies (1) are designed as LED light-emitting assemblies.

13. A backlight module chain (200), characterized in that, the backlight module chain (200) comprises at least two back^¬ light modules (100) according to any of Claims 1-12.

14. The backlight module chain (200) according to Claim 13, characterized in that, the backlight modules (100) are con^¬ nected in parallel with each other.

15. The backlight module chain (200) according to Claim 14, characterized in that, the backlight module chain (200) is driven by a constant voltage source.

16. A light box (300), characterized in that, the light box comprises at least one backlight module chain (200) according to any of Claims 13-15.

17. The light box (300) according to Claim 16, characterized in that, the light box (300) further comprises a second dif^¬ fusion sheet (5) disposed on a light emergent opening of the light box (300) .