Patent Publication Number: US-2011063232-A1

Title: Projective-capacitive touch panel and fabrication method thereof

Description:
FIELD OF THE INVENTION 
     The present invention relates to a touch panel and a fabrication method thereof, and more particularly to a projective-capacitive touch panel and a fabrication method thereof. 
     BACKGROUND OF THE INVENTION 
     A projective-capacitive touch panel is implemented based on a traditional capacitive touch panel and further includes two sets of transparent wires (X and Y) implemented on two different planes and perpendicular to each other and a plurality of driving wires. 
     Please refer to  FIG. 1 , which is a schematic diagram showing a traditional projective-capacitive touch panel according to the prior art. In  FIG. 1 , the projective-capacitive touch panel  1  includes sequentially a glass substrate  11  as a substrate, an X pattern layer  12  as a first pattern layer, an X pattern protection layer  13  as a first protection layer, a metal trace layer  14 , a metal trace protection layer  15  as a second protection layer, a Y pattern layer  16  as a second pattern layer, and a top-coating layer  17  as an insulation layer. 
     Please refer to  FIG. 2 , which is a flow chart schematically showing the fabrication method for the traditional projective-capacitive touch panel of  FIG. 1  according to the prior art. 
     (Step  21 ) A glass substrate  11  as a substrate is provided. 
     (Step  22 ) An ITO (Indium Tin Oxide) layer is formed on the glass substrate  11 . A coating process, an exposing process, a developing process, an etching process, and a stripping process are sequentially proceeded with some sort of photo-resist (A) on the ITO layer so as to form the X pattern layer  12  as the first pattern layer. Specifically, a first photo mask is used in the step. 
     (Step  23 ) A coating process, an exposing process, a developing process, an etching process, and a stripping process are sequentially proceeded with some sort of photo-resist (B) on the X pattern layer  12  so as to form the X pattern protection layer  13  as the first protection layer. Specifically, a second photo mask is used in the step. 
     (Step  24 ) A metal layer is sputtered on the X pattern protection layer  13 . A coating process, an exposing process, a developing process, an etching process, and a stripping process are sequentially proceeded with some sort of photo-resist (B) on the X pattern protection layer  13  so as to form the metal trace layer  14 . Specifically, a third photo mask is used in the step. 
     (Step  25 ) A coating process, an exposing process, a developing process, an etching process, and a stripping process are sequentially proceeded with some sort of photo-resist (B) on the metal trace layer  14  so as to form the metal trace protection layer  15  as the second protection layer. Specifically, a fourth photo mask is used in the step. 
     (Step  26 ) An ITO layer is formed on the metal trace protection layer  15 . A coating process, an exposing process, a developing process, an etching process, and a stripping process are sequentially proceeded with some sort of photo-resist (A) on the ITO layer so as to form the Y pattern layer  16  as the second pattern layer. Specifically, a fifth photo mask is used in the step. 
     (Step  27 ) An APR (Asahiksei Photosensitive Resin) is printed and then solidified with UV light on the Y pattern layer  16  into the top-coating layer  17  as the insulation layer. 
     (Following step) The above half-finished projective-capacitive touch panel is electrically detected and then cut into a finished projective-capacitive touch panel  1 . 
     The above fabrication method for the traditional projective-capacitive touch panel has the following drawbacks: 
     (1) The total fabrication process has five photo mask procedure and one APR procedure, which complicate the fabrication method. Besides, the fabrication equipments tend to be fully loaded since the coating process, the exposing process, the developing process, the etching process, and the stripping process are repeatedly proceeded. 
     (2) The environment is polluted for the increase of the acid wash procedures. 
     (3) To prevent the two pattern layers and the metal trace layer from being eroded by the acid solution, it is necessary to implement another protection layer therebetween. Since being slight acidic, the additional protection layer will have an unfavorable effect on the reliability of the trace. Moreover, the additional protection layer will also decrease the penetrability of the panel for light. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a projective-capacitive touch panel and a fabrication method thereof for simplifying the fabrication process, decreasing the cost and improving the performance of the products. 
     According to the foregoing object of the present invention, a fabrication method of a projective-capacitive touch panel is provided. The method includes steps of: providing a substrate; forming a metal trace layer on the substrate with a first exposing/developing process and a etching/stripping process sequentially; forming a first pattern layer on the metal trace layer with a second exposing/developing process, a first filming process and a first stripping process sequentially; forming a insulation layer on the first pattern layer; and forming a second pattern layer on the insulation layer with a third exposing/developing process, a second filming process and a second stripping process sequentially. 
     According to the foregoing object of the present invention, a projective-capacitive touch panel is also provided. The projective-capacitive touch panel includes: a substrate; a metal layer on the substrate; a first pattern layer on the metal layer; a top-coating layer on the first pattern layer; and a second pattern layer on the top-coating layer. 
     By the above projective-capacitive touch panel and a fabrication method thereof, the fabrication process can be shortened, the quantity of the photo mask can be decreased, and the fabrication cost can be lowered. The environment pollution will also be prevented while the penetrability of the panel for light will be increased. 
     The foregoing and other features and advantages of the present invention will be more clearly understood through the following descriptions with reference to the drawings, wherein: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing a traditional projective-capacitive touch panel according to the prior art; 
         FIG. 2  is a flow chart schematically showing the fabrication method for the traditional projective-capacitive touch panel of  FIG. 1  according to the prior art; 
         FIG. 3  is a flow chart schematically showing the fabrication method for the projective-capacitive touch panel according to the present invention; 
         FIG. 4  is a schematic diagram showing the structure of the projective-capacitive touch panel fabricated with the fabrication method of  FIG. 3  according to the present invention; 
         FIG. 5(   a ) is a schematic diagram showing a lateral view of the structure of the projective-capacitive touch panel of  FIG. 4  according to the present invention; and 
         FIG. 5(   b ) is a schematic diagram showing another lateral view of the structure of the projective-capacitive touch panel of  FIG. 4  according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for the purposes of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed. 
     Please refer to  FIG. 3 , which is a flow chart schematically showing the fabrication method for the projective-capacitive touch panel according to the present invention. The fabrication method for the projective-capacitive touch panel is described as follows. 
     (Step A) A glass substrate as a substrate is provided. 
     (Step B) A metal trace layer is formed on the substrate with a first exposing/developing process and an etching/stripping process sequentially. In this step, a metal layer is sputtered on the glass substrate, some sort of photo-resist (A) is coated on the metal layer, and then the first exposing/developing process and the etching/stripping process are sequentially implemented on the metal layer so as to form the metal trace layer. Specifically, a first photo mask is used in the step. 
     (Step C) A first pattern layer is formed on the metal trace layer with a second exposing/developing process, a first filming process and a first stripping process sequentially. In this step, some sort of photo-resist (B) is coated on the metal trace layer, the second exposing/developing process is implemented on the photo-resist layer, a first ITO layer is formed with the first filming process, and then the first stripping process is implemented on the first ITO layer so as to form an X pattern layer as the first pattern layer. 
     (Step D) An APR (Asahiksei Photosensitive Resin) is printed and then solidified with UV light on the X pattern layer into the top-coating layer as the insulation layer. 
     (Step E) A second pattern layer is formed on the top-coating layer with a third exposing/developing process, a second filming process and a second stripping process sequentially. In this step, some sort of photo-resist (B) is coated on the top-coating layer, the third exposing/developing process is implemented on the photo-resist layer, a second ITO layer is formed with the second filming process, and then the second stripping process is implemented on the second ITO layer so as to form an Y pattern layer as the second pattern layer. 
     (Following step) The above half-finished projective-capacitive touch panel is electrically detected and then cut into a finished projective-capacitive touch pane. 
     Please refer to  FIG. 4 , which is a schematic diagram showing the structure of the projective-capacitive touch panel fabricated with the fabrication method of  FIG. 3  according to the present invention. In  FIG. 4 , the projective-capacitive touch panel  4  includes a glass substrate  41  as a substrate, a metal trace layer  42 , an X pattern layer  43  as a first pattern layer, a top-coating layer  44  as an insulation layer, and a Y pattern layer  45  as a second pattern layer. 
     Please refer to  FIG. 5(   a ), which is a schematic diagram showing a lateral view of the structure of the projective-capacitive touch panel of  FIG. 4  according to the present invention. As  FIG. 5(   a ) shows, the projective-capacitive touch panel  5  includes a glass substrate  51 , metal traces  52 , an X pattern layer  53 , a top-coating layer  54 , and a Y pattern layer  55 . Besides, please refer to  FIG. 5(   b ), which is a schematic diagram showing another lateral view of the structure of the projective-capacitive touch panel of  FIG. 4  according to the present invention. As  FIG. 5(   b ) shows, it is also clear that the projective-capacitive touch panel  5  includes the glass substrate  51 , metal traces  52 , the X pattern layer  53 , the top-coating layer  54 , and the Y pattern layer  55 . 
     In sum, the projective-capacitive touch panel and a fabrication method thereof provided in the present invention can effectively decrease the quantity of the photo mask used in the fabrication process from five to three, which simplifies the fabrication process and decreases the cost. Moreover, the environment pollution will also be prevented while the penetrability of the panel for light will be increased. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.