Abstract:
A backlight module and a frame thereof are provided, which comprises an outer frame, an elastic side frame, a connecting arm and a cantilever. Here, the elastic side frame is disposed on the at least one side of the outer frame. The connecting arm is connected to a surface of the elastic side frame. The cantilever is disposed on the connecting arm, and formed a first space with the elastic side frame. The frame of the backlight can protect optical films or panel and sustain optical films against higher stress.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a backlight module, and more particularly, to a backlight module having a frame adapted for protecting optical films. 
         [0003]    2. Description of Related Art 
         [0004]    Nowadays, liquid crystal displays (LCDs) have become very common in the fields of information and electrical appliances, and thus are widely popular among consumers due to merits of low price and matured manufacturing techniques. 
         [0005]    LCDs adopt a passive-display measure, i.e. relying on illumination of a backlight module lamp. An LCD primarily consists of a liquid crystal display panel and a backlight module. The backlight module provides the panel uniform and sufficient light, and is one of the key optical modules for an LCD. In a traditional backlight module, light is transmitted from a lamp, through a light guide, to an optical film (for example, a diffuser), and then to the LCD panel. 
         [0006]    However, the cost for manufacturing optical films of the backlight modules is by no means low, yet optical films have a great influence on the quality of LCDs. Factors affecting manufacture of desirable backlight modules reside in positioning, supporting and expansion rate of optical films. It is significant to protect optical films so as to prevent them from fracture under impact. 
         [0007]    Referring to  FIG. 1 , an exploded view illustrating a conventional backlight module, the backlight module comprises an outer frame  1 , two elastic side frames  10  each disposed at one side of the outer frame  1 , respectively, and a light guide  11  and optical films  12  supported at top of the elastic side frame  10 . The elastic side frame  10  has a rib  101 , and the light guide  11  and the optical film  12  are respectively provided with a recess  111 ,  121  at a location corresponding to the rib  101 . The rib  101  of the elastic side frame  10  can be configured as the one shown in  FIGS. 2A and 2B , i.e., an enlarged top view and a perspective view illustrating engagement of the optical film  12  and the rib  101  on the conventional backlight module. In the conventional backlight module, upon a shock or impact, an external force from Y direction makes the elastic side frame  10  incur a stress and in particular, a stress occurs at the corner  122  of the recess  121  of the optical film  12 . Furthermore, upon an external force from an X direction, a stress will similarly occur at the corner  122  of the recess  121  of the optical film  12 . As a result, the optical film  12  fractures due to the shock or impact. It, therefore, becomes an issue as to how to prevent the optical films of the backlight modules from fracture so as to raise yield rate of the LCDs. 
       SUMMARY OF THE INVENTION 
       [0008]    According to the present invention, a backlight module frame includes an outer frame, an elastic side frame, a connecting arm, and at least one cantilever. The elastic side frame is disposed on at least one side of the outer frame; the connecting arm is connected to a surface of the elastic side frame; and the cantilever is disposed on the connecting arm, where a first spacing is formed between the cantilever and the elastic side frame. 
         [0009]    Still according to the present invention, a backlight module includes an outer frame, an elastic side frame, a connecting arm, at least one cantilever, a plurality of lamps, and at least one optical film. The elastic side frame is disposed on at least one side of the outer frame; the connecting arm is connected to a surface of the elastic side frame; the at least one cantilever is disposed on the connecting arm, wherein a first spacing is formed between the cantilever and the elastic side frame. The connecting arm is connected with the elastic side frame and the at least one cantilever so as to maintain the first spacing. The plural lamps are disposed on the outer frame; and the at least one optical film has at least one recess, wherein the at least one optical film is disposed on the top of the elastic side frame and the film recess envelops the at least one cantilever. 
         [0010]    In the backlight module according to the present invention, the lamp primarily owns its merit in providing sufficient brightness for the backlight module, where the lamp can be cold cathode fluorescent lamp (CCFL) or light emitting diode (LED). 
         [0011]    According to the present invention, at least one end side of the cantilever has an extension portion, and a second spacing is formed between the extension portion and the top of the elastic side frame. Therefore, the stress at Y direction can be reduced by such extension portion. Also, the cantilever itself is capable of stress release at Y direction of the elastic side frame. The at least one cantilever has a recess, and a third spacing is formed between the cantilever and the connecting arm, thus the stress at X direction of the elastic side frame can be reduced. Besides, two L-shaped structures are formed in the cantilever with the formation of the recess, such that the two L-shaped structures may ease the stress at X direction of the elastic side frame too. The cantilever of the present invention disposes mainly on the top of the elastic side frame in order to release the stresses from both X and Y direction and to provide a protection to the optical films. 
         [0012]    Meanwhile, the optical film, disposed on the top of the elastic side frame and having a recess, of the present invention can be a prism sheet, a diffuser plate, a reflector plate, or a protecting film. 
         [0013]    Furthermore, the elastic side frame can be simultaneously produced with the cantilever and the connecting arm by using a single-mold injection method. The elastic side frame may be made of metal, plastic, or complex materials. Polyester is preferred when a plastic is selected. 
         [0014]    Subsequently, the elastic side frame of the present invention may be disposed at two sides of the outer frame, in which the cantilever locating at both sides of the outer frame can be one or more, and the cantilevers at both sides of the outer frame can be disposed in a symmetrical way or an asymmetrical arrangement. 
         [0015]    The material of the outer frame is not limited but preferably is metal, plastic, or complex materials. 
         [0016]    The backlight module of the present invention is preferably a bottom lighting backlight module. 
         [0017]    When optical films are placed on the top of the elastic side frame, the cantilever provided may serve as a cushion, a proof-thinking device (error-free device), and a positioning device simultaneously. According to the present invention, the safety of the optical films is particularly secured, thus the original shape of the optical films is maintained and a good optical performance is easily provided by those optical films. By using the elastic side frame of the present invention, outer forces applied to the optical film are uniformly distributed, thus the stresses are efficiently reduced, and the producing yield of the LCD devices can be improved. Furthermore, the cost for manufacturing LCD devices can be lowered. 
         [0018]    Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is an exploded view illustrating a conventional backlight module; 
           [0020]      FIG. 2A  is an enlarged top view illustrating an engagement of part of an optical film and an elastic side frame on the conventional backlight module; 
           [0021]      FIG. 2B  is a perspective view illustrating the engagement of part of the optical film and the elastic side frame on the conventional backlight module shown in  FIG. 2A ; 
           [0022]      FIG. 3  is a schematic view illustrating an elastic side frame according to the present invention; 
           [0023]      FIG. 4  is an enlarged perspective view illustrating part of the elastic side frame according to Embodiment 1 of the present invention, as circled A in  FIG. 3  (Area A); 
           [0024]      FIG. 5  is an enlarged perspective view illustrating part of the elastic side frame according to Embodiment 1 of the present invention, as circled B in FIG.  3 (Area B); 
           [0025]      FIG. 6  is an enlarged perspective view illustrating Area A of the elastic side frame according to Embodiment 2 of the present invention; 
           [0026]      FIG. 7  is an enlarged perspective view illustrating Area B of the elastic side frame according to Embodiment 2 of the present invention; 
           [0027]      FIG. 8  is an upper view of the elastic side frame according to the Comparative Embodiment of the present invention; 
           [0028]      FIGS. 9A ,  9 B, and  9 C are experimental results of the stress received at a Y direction after being exposed to shock from an outer force, and each of  FIGS. 9A ,  9 B, and  9 C represents the Comparative Embodiment, Embodiment 1, and Embodiment 2, respectively; 
           [0029]      FIGS. 10A and 10B  are results of the stress received at an X direction after being exposed to shock from an outer force, and each of  FIGS. 10A and 10B  represents the Comparative Embodiment and a preferred embodiment of the present invention, respectively; 
           [0030]      FIGS. 11A and 11B  are results of the stress received at an X direction after being exposed to shock from an outer force, and each of  FIGS. 11A and 11B  represents the Comparative Embodiment and a preferred embodiment of the present invention, respectively; and 
           [0031]      FIG. 12  is an exploded view illustrating a backlight module of Embodiment 1 of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0032]    Specific embodiments will be proposed as follows for implementation of the present invention. It is understood that one skilled in the art can readily perceive advantages and functions of the present invention in reference to the description hereinafter. The present invention can be practiced through various embodiments, where details described below can be modified in terms of different views and implementations within the spirit of the present invention. 
         [0033]    In the drawings illustrating the embodiments of the present invention schematic views are presented. Nevertheless, the drawings only serve to show the elements relevant to the present invention, despite that configuration of the elements may not necessarily be similar to that as practically implemented. Besides, the number of elements or shapes thereof as practically implemented are optionally proportioned, though may be more complex in a real configuration of elements. 
       Embodiment 1 
       [0034]    Embodiment 1 of the present invention is to provide a backlight module frame and a backlight module in use of the frame. Now referring to  FIGS. 3 to 5 , an elastic side frame  21 , made of polyester, includes a cantilever  22 , and a connecting arm  23 . Also referring with  FIG. 12 , the backlight module having the elastic side frame  21  of the present Embodiment 1 is presented. As shown in  FIG. 4 , the connecting arm  23  is fixed to a surface of the elastic side frame  21 , and the cantilever  22  is disposed on the connecting arm  23  and is located above the elastic side frame  21 , where a first spacing  211  is formed between the cantilever  22  and the elastic side frame  21 . The cantilever  22 , disposed above the elastic side frame  21 , has two extension portions  221  (each independently having a protrusion  22   a ) at the two end sides of the cantilever  22 , where each of the extensions&#39; protrusion  22   a  and the elastic side frame  21  form a second spacing  212 . In other words, the extension portions  221  are suspended from the cantilever  22 , such that the cantilever  22  has an L-shaped structure at Area A. The cantilever  22  at Area A act as a cushion for the elastic side frame  21  to buffer against the stress from Y-direction. Further, as shown in  FIGS. 3 and 5 , a recess  223  is formed at Area B of the cantilever  22 , and a third spacing  231  is formed at B Area between the cantilever  22  and the connecting arm  23 . The cantilever  22  at Area B serves the elastic side frame  21  with a buffer against an X-direction stress. In the present embodiment, the elastic side frame  21 , the cantilever  22 , and the connecting arm  23  are integrally made with single-mold injection. Hence, stresses on the cantilever  22  and optical films will be reduced because of the second spacing  212  formed between the elastic side frame  21  and the cantilever  22 , and the third spacing  231  formed between the cantilever  22  and the connecting arm  23 . The cantilever  22 , disposed above the elastic side frame  21 , is not limited to only singular, but rather can be plural. In addition, the cantilevers  22 , each disposed on the elastic side frame  21  which is to be disposed one at each side of the outer frame  1  shown in  FIG. 12 , may or may not be symmetric with each other. 
         [0035]    In the present embodiment, a backlight module may be provided. In this respect,  FIG. 12  can be referenced as an exploded view of the backlight module, where, instead, the elastic side frame  21  is disposed at each side of the outer frame. There are plural lamps (not shown) arranged on the outer frame  1 , where the lamps can be CCFLs or LEDs. In the present embodiment, the lamps are CCFLs. A light guide  11  and optical films  12  are disposed, in sequence, on the top of the elastic side frame  21 . The light guide  11  and the optical film  12  are each provided with a recess  111 ,  121  at a location corresponding to the cantilevers  22  according to the present embodiment. The light guide recess  111  and the optical film recess  121  envelop the cantilever  22 . Eventually, a backlight module according to the present embodiment is accomplished. 
       Embodiment 2 
       [0036]    Now reference is made to  FIGS. 6 and 7 , which are schematic views of Area A and Area B of the cantilever  22  shown in  FIG. 3 , respectively. As illustrated in  FIG. 6 , a second spacing  212  is formed between the extension portion  221  and the elastic side frame  21 ; the connecting arm  23  is elongated and connecting with the cantilever  22 . Similarly as in Embodiment 1, the cantilever  22  at Area A of the present Embodiment act as a cushion for the elastic side frame  21  to buffer against the stress from Y-direction. Referring with  FIG. 7 , the cantilever  22  at Area B is cut off and forms a break  220 , thus a pair of L-shaped structures at Area B is formed. Such L-shaped structure at Area B may provide a cushion for the elastic side frame  21  against the stress from X-direction. Also, the elastic side frame  21  and the extension portion  221  are integrally made with single-mold injection. Thereby, such cantilever  22  is able to reduce the deformation or damage otherwise caused by the outer stresses. 
       Comparative Embodiment 1 
       [0037]    As shown in  FIG. 8 , an elastic side frame of the present Comparative Embodiment is presented. The material of the elastic side frame  31  of the present Comparative Embodiment is the same as that of the Embodiment 1. The rib  32  locating on the elastic side frame  31  is different from the cantilever  22  of the Embodiment 1 and 2. Though the elastic side frame  31  is the same as the elastic side frame  21  of the Embodiments 1 and 2, the difference is that there is no such third spacing  231  and second spacing  212  formed in the present Comparative Embodiment as in the Embodiments 1 and 2. That is, the rib  32  connects to the elastic side frame  31  entirely without any spacing. 
       Experiment Embodiment 
       [0038]      FIG. 9A  shows an experimental result of the stress received at a Y direction after being exposed to shock from an outer force according to the Comparative Embodiment of the present invention.  FIGS. 9B and 9C  are experimental results of the stress received at a Y direction after being exposed to shock from an outer force according to the Embodiment 1 and Embodiment 2, respectively. With reference to  FIGS. 9A ,  9 B, and  9 C, the dark color and light color observed represent a small force and a large force received, respectively. A diffuser plate is used here to be an optical film in the experiment. It can be seen in  FIG. 9A , which represents the experimental result of the Comparative Embodiment (without an outer frame as that of the present invention), there is still some stress received by the diffuser plate and this may cause breaks in the diffuser plate when an outer force is applied thereto. Meanwhile, in regard to the diffuser plate of the Embodiment 1 and Embodiment 2 respectively, the testing results in  FIGS. 9B and 9C  show no stress received at a Y direction, which means the safety of the diffuser plate is guaranteed. 
         [0039]    With reference to  FIGS. 10A and 10B , in which results of the stress received at an X direction after are exposed to shock from an outer force of the Comparative Embodiment and a preferred embodiment (e.g. Embodiment 1 and 2) of the present invention are shown. Accordingly,  FIGS. 11A and 11B  are side views related to  FIGS. 10A and 10B  respectively. In the same way as  9 A- 9 C, the dark color and light color observed in the figures represent a small force and a large force received, respectively. Thus it can be seen that, as for the elastic side frame, stresses occur when an outer force is applied from the X direction into the elastic side frame in the Comparative Embodiment. Conversely, stresses are effectively reduced in the elastic side frame of the backlight module according to the present invention. Therefore, the backlight module having the frame according to the present invention is able to pass mechanical test with more critical conditions and be applied to a large area display panel. 
         [0040]    As demonstrated above, elastic side frames having cantilevers are provided in the backlight module and the frame thereof according to the present invention, thus stresses can be reduced and the safety of the optical films in the backlight module are more guaranteed. Meanwhile, the process of providing the elastic side frame and the cantilever by single-mold injection may achieve the requirement of low cost. Furthermore, the elastic side frame of the present invention may resist a greater outer stress applied thereto, therefore, it is able to pass mechanical test with more critical conditions and be applied to a large area display panel, and the producing yield of the LCD devices may be improved. 
         [0041]    Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed.