Abstract:
A method for making a luminescent key. The key has a 3-dimensional shape and is extraordinarily thin. Besides, the key evenly emits luminescence. The key can be used in a mobile phone to save space so that more components can be put in to the mobile phone.

Description:
FIELD OF THE INVENTION 
   The present invention relates to fabricating a pressing key; more particularly, relates to fabricating a luminescent solid key. 
   DESCRIPTION OF THE RELATED ART(S) 
   A general handheld device in the 3C (Computer, Communication and Consumer Electronics) field relies much of its functions and appearance on the pressing keys. The keys are required for operating and controlling the functions of a 3C device and for making its appearance beautiful. Therefore, the keys play an important part both in its functions and in its appearance. 
   A key for a general handheld device is usually fabricated in two ways: one is to inject plastic material into a mold to obtain a base with keys on it; the other is to inject plastic material into a mold to obtain a plurality of single keys to be set on a base. 
   The key fabricated through either of the above two methods is coordinated with a mold so that a certain thickness is formed. As long as the functions of a mobile phone increase day by day, more components have to be put into a limited space so that a pressing key has to become thinner. Yet, as is said, no matter whether the key is deposed on an EL (Electro-Luminescent) film or is made of a LED (Light Emitting Diode), a certain thickness (about 0.8 millimeter) is required, where thinness is deprived and cost lies together with a complex procedure. Hence, the prior arts do not fulfill users&#39; requests on actual use. 
   SUMMARY OF THE INVENTION 
   The main purpose of the present invention is to fabricate a luminescent solid key with thinness and even luminescence while saving cost and procedure. 
   To achieve the above purpose, the present invention is a method for fabricating a luminescent solid key, comprising steps of obtaining a substrate having a base, an image layer, a first conductive layer, a light-emitting layer, a dielectric layer, a second conductive layer and an insulation layer sequentially; pre-shaping the substrate; obtaining a pressing layer having a plurality of contacting units on the insulation layer; and cutting the substrate to obtain at least one lightening solid key. Accordingly, a novel method for fabricating a luminescent solid key is obtained. 

   
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in conjunction with the accompanying drawings in which 
       FIG. 1  is a view showing the flow chart of the preferred embodiment according to the present invention; 
       FIG. 2  to  FIG. 10  are cross-sectional views showing the products after step (A) to step (I) of the preferred embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The following description of the preferred embodiment is provided to understand the features and the structures of the present invention. Please refer to  FIG. 1 , which is a view showing the flow chart of the preferred embodiment according to the present invention. As shown in the figure, the present invention is a method for fabricating a luminescent solid key, comprising the following steps: 
   Step (A): A base is provided; and, an image layer is formed on a surface of the base. 
   Step (B): A first conductive layer is formed on the image layer. 
   Step (C): A light-emitting layer is formed on the first conductive layer. 
   Step (D): A dielectric layer is formed on the light-emitting layer. 
   Step (E): A second conductive layer is formed on the dielectric layer. 
   Step (F): An insulation layer is formed on the second conductive layer so that a substrate, sequentially having the base, the image layer, the first conductive layer, the light-emitting layer, the dielectric layer, the second conductive layer and the insulation layer, is obtained. 
   Step (G): The substrate is pre-shaped. 
   Step (H): A pressing layer having a plurality of contacting units is formed on the insulation layer of the substrate. 
   Step (I): Finally the substrate is cut to obtain at least one lightening solid key. 
   Thus, with the above steps, a novel method for fabricating a luminescent solid key is obtained. 
   Please refer to  FIG. 2 , which is a cross-sectional view showing the product after step (A) of the preferred embodiment. As shown in the figure, in step (A), a base  11  is provided with a thickness between 0.05 millimeter (mm) and 0.30 mm, which is made a transparent material of Polycarbonate (PC), Polymethylmethacrylate (PMMA), Polyurethane (PU), Polyethylene Terephthalate (PET), Polybutylene Terephthalate (PBT) or Acrylonitrile Butadiene Styrene (ABS). And an image layer  12  is deposed on the base  11 , where the image layer is made of PC, PMMA, PU, epoxy or polyester; the image layer has a thickness between 0.1 mm and 0.2 mm; and the image layer is printed with a colorful image through a chromolithography by using a printing ink mixed with a fluorescent powder. 
   Please further refer to  FIG. 3 , which is a cross-sectional view showing the product after step (B). 
   As shown in the figure, a first conductive layer  13  is printed on the image layer  12 , where the first conductive layer  13  has a thickness between 0.01 mm and 0.2 mm; and the first conductive layer  13  is connected with an electrode (not shown in the figure) to conduct a current. 
   Please further refer to  FIG. 4 , which is a cross-sectional view showing the product after step (C). As shown in the figure, in step (C), a light-emitting layer  14  is printed on the first conductive layer  13 , where the light-emitting layer  14  is made of an electroluminescence fluorescent powder having a thickness between 0.02 mm and 0.2 mm. 
   Please further refer to  FIG. 5 , which is a cross-sectional view showing the product after step (D). As shown in the figure, in step (D), a dielectric layer  15  is printed on the light-emitting layer  14 , where the dielectric layer  15  is made of barium titanate (BaTiO 3 ) with a thickness between 0.001 mm and 0.1 mm. 
   Please further refer to  FIG. 6 , which is a cross-sectional view showing the product after step (E). As shown in the figure, in step (E), a second conductive layer  16  is printed on the dielectric layer  15 , where the second conductive layer  16  is made of a conductive printing ink of a conductive silver paste or a conductive carbon black, having a thickness between 0.001 mm and 0.2 mm. The second conductive layer is connected with an electrode (not shown in the figure) to conduct a current coordinated with the first conductive layer  13 . 
   Please further refer to  FIG. 7 , which is a cross-sectional view showing the product after step (F). As shown in the figure, in step (F), an insulation layer  17  is printed on the second conductive layer  16 , where the insulation layer  17  is made of an insulation ink of PC, PMMA, PU, silicon, epoxy or polyester having a thickness between 0.001 mm and 0.1 mm. After step (F), a substrate  21 , having the base  11 , the image layer  12 , the first conductive layer  13 , the light-emitting layer  14 , the dielectric layer  15 , the second conductive layer  16  and the insulation layer  17 , is obtained. 
   Please refer to  FIG. 8 , which is a cross-sectional view showing the product after step (G). As shown in the figure, in step (G), the substrate  21  obtained after step (F), as shown in  FIG. 7 , is stretched to obtain a plate having a thickness between 0.05 mm and 0.50 mm; or obtains a perspective convex shape through a mold with a forming machine. Thus the substrate  21  is pre-shaped. 
   Please refer to  FIG. 9 , which is a cross-sectional view showing the product after step (H). As shown in the figure, in step (H), a pressing layer  31  having a plurality of contacting units  311  is pasted on the insulation layer  17  of the substrate  21  obtained after step (F), as shown in  FIG. 8 , where the pressing layer  31  is made of a soft plastic or a soft rubber, which is Thermoplastic Urethane (TPU), Thermal Plastic Rubber (TPR) or Thermoplastic Elastomer (TPE), having a thickness between 0.05 mm and 0.4 mm through pouring, pressing and Injecting with the soft plastic or the soft rubber. 
   Please refer to  FIG. 10 , which is a cross-sectional view showing the product after step (I). As shown in the figure, in step (I), the substrate  21  obtained after step (G), as shown in  FIG. 9 , is cut by a laser marking, a Computer Numerically Controlled (CNC) cutting and a punching so that a lightening solid key is obtained according to a requirement. 
   As a result, the present invention has the following characteristics: 
   1. The substrate can be extraordinarily thin. A film for preventing the fluorescent powder from getting wet is replaced with the film of the pressing key directly so that a thickness of a film layer is saved. Besides, the thickness of the film of the pressing key can be thicker than the original film used so that the wetness prevention can be better. 
   2. The shape is convex so that the luminescence obtained is even. Because the film of the pressing key is used as a base, the film can be fabricated into a solid form. In such a way, the base can be stretched more easily than a general light-emitting film to be fabricated for a wider application. 
   3. The pressing keys can be rapidly and massively produced. 
   4. The cost and procedure can be saved. The present invention combines the original two processes for making a pressing key into a whole one process so that the cost is saved at the same time. 
   To sum up, the present invention is a method for fabricating a luminescent solid key, combining a pressing key and a film, where a luminescent solid key obtained is extraordinarily thin and the luminescence the key emitted is even. 
   The preferred embodiment herein disclosed is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present invention.