Abstract:
A keyboard device including a frame made of two materials, a keypad film, and multiple button assemblies is provided. The frame made of two materials includes a bottom plate and multiple fixing structures, wherein the fixing structures are integrally formed at the bottom plate by in-mold injection. The keypad film is disposed on the frame made of two materials, and the button assemblies are disposed on the keypad film and assembled to the fixing structures.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefit of Taiwan application serial no. 98131388, filed on Sep. 17, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a device, and in particular relates to a keyboard device. 
         [0004]    2. Description of Related Art 
         [0005]      FIG. 1  is a schematic view depicting a frame of a conventional keyboard device. Referring to  FIG. 1 , a frame  100  of the conventional keyboard device is fabricated by processing a metal plate  110  to form fixing structures  120  and constraining structures  130  on a bottom plate. More specifically, the metal plate  110  is punched and bent several times, so as to form the fixing structures  120  and the constraining structures  130 . Generally speaking, the punching and bending processes are performed 6-8 times. Therefore, the material of the fixing structures  120  and the constraining structures  130  is the same as the material of the metal plate  110 . 
         [0006]    Since the processes are performed so many times, the production costs cannot be lowered. In addition, the metal may easily break after being bent several times, resulting in the poor yield rate of the frame  100 . As a consequence, the costs for fabricating the frame  100  are high. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention provides a keyboard device requiring low production costs. 
         [0008]    The invention provides a keyboard device, including a frame, a keypad film, and a plurality of button assemblies. The frame includes a bottom plate and a plurality of fixing structures, wherein the fixing structures are located on the bottom plate. Moreover, the fixing structures and the bottom plate are integrally formed by in-mold injection. The keypad film is disposed on the frame. The button assemblies are disposed on the keypad film and assembled to the fixing structures. 
         [0009]    According to an embodiment of the invention, a material of the bottom plate is metal. 
         [0010]    According to an embodiment of the invention, a material of the fixing structures is plastic. 
         [0011]    According to an embodiment of the invention, the keypad film includes a plurality of push switches, and the button assemblies are correspondingly disposed on the push switches. 
         [0012]    According to an embodiment of the invention, the keypad film has a plurality of openings, and the openings are disposed corresponding to the fixing structures. 
         [0013]    According to an embodiment of the invention, each of the fixing structures includes a pair of positioning bumps and a pair of constraining bumps, wherein each of the button assemblies is assembled to one pair of positioning bumps, and the constraining bumps are disposed opposite to the positioning bumps corresponding thereto. In addition, each of the button assemblies includes a first holder, a second holder, and a key cap, wherein an end of the first holder is assembled to one pair of positioning bumps, and the second holder is pivotally assembled to the first holder and constrained by the corresponding constraining bumps. The key cap is assembled to the first holder and the other end of the second holder that is not assembled to the fixing structures. 
         [0014]    According to an embodiment of the invention, the bottom plate has a plurality of through holes, and each of the fixing structures passes through the corresponding through hole to be formed on the bottom plate. The bottom plate further includes a plurality of protrusive structures, and the through holes are located in the protrusive structures correspondingly. 
         [0015]    Based on the above, the frame in the keyboard device of the invention is formed by in-mold injection. Therefore, the processes performed during the fabrication of the frame are reduced, the production costs are lowered, and the yield rate is increased. 
         [0016]    In order to make the aforementioned and other features and advantages of the invention more comprehensible, several embodiments accompanied with drawings are described in detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0018]      FIG. 1  is a schematic view depicting a frame of a conventional keyboard device. 
           [0019]      FIG. 2  is a flowchart illustrating a method for forming a frame of a keyboard device according to the present embodiment. 
           [0020]      FIG. 3  depicts the frame formed by the process as shown in  FIG. 2 . 
           [0021]      FIG. 4  is a schematic view of a keyboard device equipped with the frame fabricated by the processes shown in  FIG. 2 . 
           [0022]      FIG. 5A  is a cross-sectional view of a frame according to another embodiment of the invention. 
           [0023]      FIG. 5B  is a perspective view of  FIG. 5A . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0024]      FIG. 2  is a flowchart illustrating a method for forming a frame of a keyboard device according to the present embodiment, and  FIG. 3  depicts the frame formed by the process shown in  FIG. 2 . Referring to  FIGS. 2 and 3 , as shown in Step S 110 , a metal plate  210  is provided and processed. A method for processing the metal plate  210  is to punch the metal plate  210 , so as to form a plurality of through holes  214  in the metal plate  210 . Thereafter, as in Step S 120 , an in-mold injection process is performed on the metal plate  210  to form a plurality of fixing structures  220  for constituting a frame  310 . A material of the fixing structures  220  is different from the material of the metal plate  210 . 
         [0025]    To be more specific, the punched metal plate  210  is placed in a mold. Next, a plastic molding material is filled into the mold to flow from a surface  212  of the metal plate  210  to the other surface  216  thereof through the through holes  214  and then cures to form the fixing structures  220  on the metal plate  210 . A direction of filling in the plastic molding material can be varied according to actual requirements and is not limited to the descriptions here or the illustration of  FIG. 3 . It is noted that, after flowing from the surface  212  into the through holes  214 , the plastic molding material covers the surface  216  and cures thereon. The fixing structures  220  formed by curing the continuous-fluid plastic molding material is shaped like “I,” and the fixing structures  220  are securely fixed on the metal plate  210 . 
         [0026]    Compared with the conventional frame, the frame  310  that is formed by in-mold injection requires fewer fabricating processes and thus has better yield rate. 
         [0027]    The frame  310  fabricated by the above-described processes can be applied in a keyboard device.  FIG. 4  is a schematic view of a keyboard device equipped with the frame fabricated by the processes shown in  FIG. 2 . Referring to  FIG. 4 , a keyboard device  300  includes the frame  310  fabricated by the aforementioned processes, a keypad film  320 , and a plurality of button assemblies  330 . The structure and fabricating method of the frame  310  have been described in the above, and therefore not repeated hereinafter. The keypad film  320  is disposed on the frame  310 . The button assemblies  330  are disposed on the keypad film  320  and assembled to the fixing structures  220  of the frame  310 . 
         [0028]    Furthermore, the keypad film  320  includes a plurality of push switches  322 , and the button assemblies  330  are disposed on the push switches  322 . When the button assemblies  330  are pressed, the push switches  322  are pushed by the button assemblies  330  to switch on. Moreover, the keypad film  320  has a plurality of openings  324  disposed corresponding to the fixing structures  220 , so as to expose the fixing structures  220  for assembling the button assemblies  330  thereon. 
         [0029]    More specifically, each of the fixing structures  220  includes a pair of positioning bumps  222  and a pair of constraining bumps  224 , wherein each of the button assemblies  330  is assembled to one pair of the positioning bumps  222 , and the constraining bumps  224  are disposed opposite to the positioning bumps  222  corresponding thereto. In addition, each of the button assemblies  330  includes a first holder  332 , a second holder  334 , and a key cap  336 , wherein an end of the first holder  332  is assembled to one pair of the positioning bumps  222 , and the second holder  334  is pivotally assembled to the first holder  332 . An end of the second holder  334  is constrained by the corresponding constraining bumps  224 . Thus, the end of the second holder  334  can move horizontally, not vertically. The key cap  336  is assembled to the first holder  332  and the other end of the second holder  334  that is not assembled to the fixing structures  220 . 
         [0030]      FIG. 5A  is a cross-sectional view of a frame according to another embodiment of the invention, and  FIG. 5B  is a perspective view of  FIG. 5A . With reference to  FIGS. 5A and 5B , in other embodiments, a bottom plate  410  further includes a plurality of protrusive structures  412 . The through holes  414  are formed in the protrusive structures  412  correspondingly. Due to the protrusive structures  412 , the plastic molding material is cured in a recession  412   a  on an opposite surface of the protrusive structures  412 . Consequently, a surface  410   a  of the bottom plate  410  can be maintained smooth to increase the stability of assembly. In other embodiments, a direction of filling the plastic molding material and a curing position of the plastic molding material can be varied according to actual requirements. 
         [0031]    In conclusion of the above, the frame in the keyboard device of the invention is formed by in-mold injection. The processes performed during the fabrication of the frame are reduced. Accordingly, the production costs are lowered and the yield rate is increased. 
         [0032]    Although the invention has been described with reference to the above embodiments, it is apparent to one of ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit of the invention. Accordingly, the scope of the invention is defined by the attached claims not by the above detailed descriptions.