Abstract:
The present disclosure relates to a touch-on-lens (TOL) device and a method for manufacturing the same. The method includes forming a plastic layer and a touch layer; cutting the plastic layer and the touch layer; and filially laminating the plastic layer and the touch layer after cutting to a strengthened lens. The method can not only help keep good mechanical property but can also help improve the efficiency of mass production. Moreover, the present disclosure adopts a photoetching process to form a sensing pattern, thereby making the circuit thinner and beautifying the appearance.

Description:
[0001]    This application claims the benefit of China application No. 201110269450.7, filed on Sep. 1, 2011. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a touch device, and more particularly to a touch-on-lens (TOL) device and a method for manufacturing the same. 
         [0004]    2. Description of the Related Art 
         [0005]    A capacitive touch device generally comprises X-axis and Y-axis transparent electrodes. When a user touches the device, capacitance of touch point changes and a system determines location of the touch point by detecting the change in capacitance. 
         [0006]      FIG. 1A  shows a schematic stacked view of a conventional capacitive touch device that mainly comprises of a cover lens  11  and a touch substrate  12 . A touch layer, which comprises of transparent electrodes, is formed at either a single side or both sides of the touch substrate  12 .  FIG. 1B  shows a schematic stacked view of a conventional touch-on-lens (TOL) device that leaves out the a touch substrate and directly disposes a touch layer  13 , such as an ITO layer, on a cover lens  11  without adding a glass substrate so as to make the touch device thinner. 
         [0007]    Generally, there are two methods for manufacturing an existing touch-on-lens (TOL) device. The first method includes: strengthening a small piece of lens, namely a piece of lens that meets size of a touch panel, and then stacking a touch unit and other stack structures on the lens through a photoetching process. The second method includes: stacking a touch layer and other stack structures on a large-size motherboard of strengthened glass through a photoetching process, and then cutting the glass motherboard into a touch panel with a specific size through a process of glass motherboard cutting and edge polishing, etc. However, the above-mentioned two methods have some defects; for example, for the first method, cost of a single piece output is very high and efficiency of mass production is low, that do not meet economic benefit. Comparing with the first method, cost of single piece output for the second method is comparatively low and efficiency of mass production is comparatively high, but for the touch panel after cutting process, mechanical property of the glass is weakened because of no edge strengthening process. 
         [0008]    Further, there is another traditional manufacturing process including: forming a sensing pattern of a touch layer on a PET (ethylene terephthalate) film through a printing process so as to form a PET touch motherboard; and then, cutting the PET touch motherboard into a touch panel with a specific size so as to form a touch sub-panel; and finally, laminating the touch sub-panel on the strengthened lens of corresponding size. Comparing with the above-mentioned two manufacturing processes, this manufacturing process is high in efficiency of mass production and good in mechanical property. However, limited by the properties of a PET film such as incapability of high-temperature resistance, weak hardness, etc., a touch sensing pattern is formed on a PET film generally through a printing process rather than through a photoetching process. But in the process of printing the touch sensing pattern, line width of the touch sensing pattern formed by the printing method is comparatively wide due to an influence of the printing device, printing ink, and printing technique, etc., that makes the circuit visible and affects appearance of the product. Moreover, generally thickness of a PET film is 25 μm-350 μm, which reduces the capability of making the touch panel thinner. 
         [0009]    In view of the defects of conventional touch-on-lens (TOL) device and manufacturing process, it is desired to provide a novel touch-on-lens (TOL) device and a method for manufacturing the same so that the above problems can be solved. 
       SUMMARY OF THE INVENTION 
       [0010]    An object of the embodiments of the present disclosure is to provide a touch-on-lens (TOL) device and a method for manufacturing the same, forming a touch layer with a large area on a plastic layer through a photoetching process and improving existing problems of low efficiency of mass production of touch-on-lens devices, bad mechanical strength, and circuit visibility, etc. through a cutting technique. 
         [0011]    According to one embodiment of the present disclosure, a method for manufacturing a touch-on-lens device comprises the following steps: (1) forming a plastic layer on a substrate; (2) forming a touch layer on the plastic layer such that the touch layer and the plastic layer form a touch film; (3) separating the touch film and the substrate; (4) cutting the touch film to form a plurality of touch modules; and (5) laminating the touch modules to a strengthened lens. 
         [0012]    In one embodiment, the plastic layer is a polyimide (PI) layer or a polyesterimide layer. 
         [0013]    In another embodiment, the touch layer comprises a sensing pattern, which is formed by a photoetching process. 
         [0014]    In yet another, the touch-on-lens device further comprises a release layer, which is formed between a plastic layer and a substrate and is made up of a silicon-based or a F-based compound. 
         [0015]    Further, adhesive strength between the substrate and the release layer is at least three times the adhesive strength between the release layer and the plastic layer. 
         [0016]    Furthermore, the touch film comprises a buffer layer that is formed between the touch layer and the plastic layer and is made up of derivative or compound of silicon. 
         [0017]    In one embodiment of the present disclosure, thickness of the plastic layer is less than 25 μm. 
         [0018]    In one embodiment, a method for manufacturing a touch-on-lens device further comprises forming a mask layer on strengthened lens, wherein the mask layer and the touch modules are at a same side of the strengthened lens. 
         [0019]    According to another embodiment of the present disclosure, a method for manufacturing a touch-on-lens device comprises the following steps: (1) forming a plastic layer on a motherboard; (2) forming a touch layer on the plastic layer so that the motherboard, the plastic layer, and the touch layer form a touch assembly; (3) cutting the touch assembly to form a plurality of touch sub-assemblies; (4) laminating the touch sub-assemblies to a strengthened lens; and (5) separating the motherboard after cutting. 
         [0020]    Further, the plastic layer is a polyimide (PI) layer or a polyesterimide layer. 
         [0021]    Further, the touch layer comprises a sensing pattern, which is formed by a photoetching process. 
         [0022]    The touch assembly further comprises a release layer, that is formed between the plastic layer and the motherboard and is made up of silicon-based or F-based compound. 
         [0023]    The touch assembly further comprises a buffer layer, which is formed between the touch layer and the plastic layer and is made up of derivative or compound of silicon. 
         [0024]    Further, the plastic layer and the touch layer of the touch assembly constitute a touch film. The touch sub-assembly comprises the motherboard and a touch module which is formed after cutting the touch film. The lamination process of step (4) further comprises laminating the touch modules of the touch sub-assemblies to the strengthened lens. 
         [0025]    The method for manufacturing a touch-on-lens device further comprises forming a mask layer on strengthened lens, wherein the mask layer and the touch modules are at the same side of the strengthened lens. 
         [0026]    According to another embodiment of the present disclosure, a touch-on-lens device comprises: a strengthened lens; and a touch module, that is laminated to the strengthened lens and formed by cutting a touch film, wherein the touch film comprises of a touch layer and a plastic layer, further wherein thickness of the plastic layer is less than 25 μm. 
         [0027]    In one embodiment of the present disclosure, thickness of the plastic layer is between 10 μm-20 μm. 
         [0028]    In one embodiment of the present disclosure, thickness of the plastic layer is between 0.5 μm-10 μm. 
         [0029]    In yet another embodiment, the plastic layer is a polyimide (PI) layer or a polyesterimide layer. 
         [0030]    In an embodiment, the touch layer comprises a sensing pattern, which is formed by a photoetching process. 
         [0031]    Further, the touch film further comprises a buffer layer, which is formed between the touch layer and the plastic layer and is made up of derivative or compound of silicon. 
         [0032]    The touch-on-lens device further comprises a mask layer, wherein the mask layer and the touch module are formed at the same side of the strengthened lens. 
         [0033]    Since the present disclosure adopts the above method, namely, first forming a plastic layer on a substrate, and then forming a touch layer on the plastic layer and finally laminating the touch layer after cutting to a strengthened lens, and since the present disclosure adopts the method of cutting first and then laminating the touch layer, the present method can not only keep good mechanical property but can also enhance efficiency of mass production. Moreover, the present disclosure adopts a photoetching process to form a sensing pattern, which can make the circuit thinner so as to beautify the appearance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1A  shows a schematic stacked view of a conventional capacitive touch device; 
           [0035]      FIG. 1B  shows a schematic stacked view of a conventional touch-on-lens (TOL) device; 
           [0036]      FIG. 2A  to  FIG. 2F  show schematic stacked views of a touch-on-lens device during the process in accordance with a first embodiment of the present disclosure; 
           [0037]      FIG. 3A  shows an electrode layer in accordance with the present embodiment; 
           [0038]      FIG. 3B  shows an insulating layer in accordance with the present embodiment; 
           [0039]      FIG. 3C  shows a conducting wire layer in accordance with the present embodiment; 
           [0040]      FIG. 4A  to  FIG. 4F  show schematic stacked views of a touch-on-lens device during the process in accordance with a second embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0041]      FIG. 2A  to  FIG. 2F  show schematic stacked views of a touch-on-lens device during the process in accordance with the first embodiment of the present disclosure. In this specification and the drawings, the upward side refers to the direction of a touch surface. Thickness of each layer shown in the drawings is not drawn according to the actual proportion. Besides, the drawings only show the main layers in accordance with the embodiments, and other layers can be inserted between the layers according to the actual need. 
         [0042]    Referring to  FIG. 2A , a transparent plastic layer  22  is firstly formed on a substrate  21 . The substrate  21  can be a glass substrate, plastic film, or other hard substrates, and the substrate  21  can be separated from the other parts so that it can be used for other processes again. In the present embodiment, the plastic layer  22  is a polyimide (PI) layer or a polyesterimide layer, but other plastics that are easy to be separated from the substrate can also be used, such as ceramic thin film (such as SiO 2 ). Comparing with conventional polyethylene terephthalate (PET), using polyimide (PI) as the material of the plastic layer  22  at least has the following effects: for example, comparatively easy to be separated from the substrate  21  in the future; high-temperature resistance; and good optical characteristics. Comparing with conventional PET, using polyesterimide as the material of the plastic layer  22  at least has the following effects: for example, high mechanical strength, high light transmittance or high chemical resistance, which can effectively protect a touch layer ( 23 ,  24 ,  25 ) from being eroded by a weak acid (such as sweat). Preferably, thickness of the plastic layer  22  is less than 25 μm. In a more preferred embodiment, thickness of the plastic layer  22  is between 10-22 μm. In a most preferred embodiment, thickness of the plastic layer  22  is between 0.5 μm-10 μm. 
         [0043]    Generally, thinner the thickness of the plastic layer  22  is, better the light transmittance of the touch panel will be and the thinner the touch panel will be. Comparing with a conventional touch-on-lens (TOL) device, the device in the present embodiment has a comparatively thin plastic layer  22 , and therefore a thinner touch-on-lens (TOL) device can be made. Besides, in order to separate more easily, the plastic layer  22  can form on the substrate  21 , a high contact-angle material, which is deposited or coated on the substrate  21  before forming the plastic layer  22 . 
         [0044]    Further, a transparent electrode layer  23 , such as a sputtering ITO layer but not limited to it, is formed on the plastic layer  22 .  FIG. 3A  shows an electrode layer  23  in accordance with the present embodiment, wherein the electrode layer  23  comprises a plurality of first electrodes  23 A along a first axis (such as Y-axis) that are connected with each other along the first axis and a plurality of second electrodes  23 B along a second axis (such as X-axis) that are not connected with each other. Sensing pattern of the electrode layer  23  can be made by a photoetching process. The photoetching process comprises photoresist coating, exposure, developing, baking, etching, stripping and other processing steps. 
         [0045]    A transparent insulating layer  24 , such as a polyimide (PI) layer but not limited to it, is formed on the electrode layer  23 .  FIG. 3B  shows an insulating layer  24  in accordance with the present embodiment, wherein the insulating layer  24  comprises a plurality of insulating blocks  24 A that respectively cover area between adjacent second electrodes  23 B along the second axis (such as X-axis). 
         [0046]    A conducting wire layer  25 , such as a sputtering metal wire layer but not limited to it, is formed on the insulating layer  24 .  FIG. 3C  shows a conducting wire layer  25  in accordance with the present embodiment, wherein the conducting wire layer  25  comprises a plurality of wire segments  25 A, which are respectively bridged over the insulating blocks  24 A to electrically couple the adjacent second electrodes  23 B along the second axis (such as X-axis) and a plurality of trace wires  25 B, which are used for electrically coupling the first-axis and the second-axis electrodes respectively and extend to the border of the touch-on-lens (TOL) device. Pattern of the conducting wire layer  25  can be made by a photoetching process. The electrode layer  23 , the insulating layer  24 , and the conducting wire layer  25  jointly form a single-layer touch layer. In an embodiment, if material of the electrode layer  23  is ITO, the single-layer touch layer can also be called as single-layer ITO (SITO). The electrode layer  23 , the insulating layer  24 , and the conducting wire layer  25  constitute a touch layer of the present embodiment, but the touch layer of the present disclosure is not limited to the above composition and arrangement methods. The plastic layer  22  and the touch layer ( 23 ,  24 ,  25 ) form a touch film, wherein the touch layer ( 23 ,  24 ,  25 ) comprises a plurality of touch units, size of which meets specific size of a touch panel. 
         [0047]    In an embodiment, a passivation layer  26  can be formed on a conducting wire layer  25 , wherein the passivation layer  26  can not only protect an electrode layer  23 , an insulating layer  24 , and a conducting wire layer  25  from damage but can also prevent them from getting oxidized or corroded. 
         [0048]    Further, a release layer  210  can be formed between substrate  21  and plastic layer  22 , for example, by using a coating technique. The release layer  210  can be made of silicon-based or F-based compound, but it is not limited to this. In one embodiment, the plastic layer  22  is a polyesterimide layer, which is formed by coating (such as spin coating) a monomer on the release layer  210  and then processing through a curing process. In one embodiment, adhesive strength between the substrate  21  and the release layer  210  is higher than (such as three times) the adhesive strength between the release layer  210  and the plastic layer  22 , which makes the plastic layer  22  easy to be separated from the release layer  210  by an external force while the release layer  210  is completely retained on the substrate  21 . 
         [0049]    Further, a buffer layer  220  can be formed between plastic layer  22  and electrode layer  23 , for example, by using a deposition technique. The buffer layer  220  can be made of derivative or compound of silicon, such as silicon nitride or silicon oxide, but it is not limited to this. In a preferable embodiment, thickness of the buffer layer  220  is 10 nm (nanometer) or more than 200 nm. By disposing the buffer layer  220 , adhesive strength between the plastic layer  22  and the touch layer ( 23 ,  24 ,  25 ) can be increased, and surface tension of the plastic layer  22  can be absorbed. 
         [0050]    Further, touch film  22 - 25  and substrate  21  can be separated to form a structure shown in  FIG. 2B . Referring to  FIG. 2C , the touch film can be cut so that each touch unit forms a touch module and each touch module can form an independent touch panel through a subsequent process. Comparing with the conventional method of manufacturing one unit by one unit, the present embodiment forms a plurality of touch units, sizes of which meet the specific size of a touch panel, on a plastic layer  22 , and then cut the formed touch units, which contributes to improvement in efficiency of mass production of the touch-on-lens (TOL) device, thereby enhancing productivity. 
         [0051]    Further, before or after forming stack structure as shown in  FIG. 2C , a strengthened lens  27  (also referred to as cover lens hereinafter) can additionally be provided, as shown in  FIG. 2D . The strengthened lens  27  can be made by cutting a glass motherboard into one that meets the size of a touch module, and then by performing an edge polishing. Comparing with the conventional method of cutting the glass after depositing the stacked touch layer, the strengthened lens  27  in the present embodiment has a strengthened edge and mechanical property. A mask layer (or a black matrix layer)  28  can be formed on the strengthened lens  27  by a printing technique. 
         [0052]    Referring to  FIG. 2E , for forming the structures of the touch module (as shown in  FIG. 2C ) and for forming the strengthened lens  27  (as shown in  FIG. 2D ) together, an adhesive layer  29 , such as liquid adhesive, can be used for gluing the two structures together; namely, the upper surface of the adhesive layer  29  can be glued to the lower surface of the strengthened lens  27  and the mask layer  28 , and the lower surface of the adhesive layer  29  can be glued to the upper surface of the passivation layer  26 . In case, the passivation layer  26  is not formed, lower surface of the adhesive layer  29  can be glued to the upper surface of the touch layer ( 23 ,  24 ,  25 ), that is, the mask layer  28  and the touch module  22 - 26  can be formed at the same side of the strengthened lens  27 . After gluing, stack structure shown in  FIG. 2F  is formed, namely, the structure from the bottom to the top comprises a plastic layer  22 , a buffer layer  220 , an electrode layer  23 , an insulating layer  24 , a conducting wire layer  25 , a passivation layer  26 , an adhesive layer  29 , a mask layer  28 , and a strengthened lens  27 . 
         [0053]    According to the above method for manufacturing a touch-on-lens (TOL) device, a touch layer ( 23 ,  24 ,  25 ) is firstly formed on a plastic layer  22  and then glued to a strengthened lens  27  that has been cut and processed with a high strength. Therefore, the requirement for strength of various end products can be reached and mass production can be carried out. For the touch-on-lens (TOL) device formed by the above process, if ITO is used as the material of the electrode layer  23 , and polyimide (PI) is used as the material of the plastic layer  22 , the process is suitable for making a curved-surface touch-on-lens device as adhesiveness of the two materials is very good and not easy to crack. Besides, the conducting wire layer  25  does not contact with the mask layer  28  directly, and therefore there will be no open circuit problem unlike the conventional problem of an open circuit being formed by height difference of the mask layer  28 . 
         [0054]      FIG. 4A  to  FIG. 4F  show schematic stacked views of a touch-on-lens device during the process in accordance with a second embodiment of the present disclosure. The present embodiment is similar to the first embodiment (as shown in  FIG. 2A  to  FIG. 2F ), in terms of the materials, thickness, manufacturing process and other effects. 
         [0055]    Referring to  FIG. 4A , a transparent plastic layer  22  is firstly formed on a motherboard  20 . The motherboard  20  can be glass substrate, plastic film or other hard substrates, and the motherboard  20  can be separated from the other parts. 
         [0056]    Further, a transparent electrode layer  23 , a transparent insulating layer  24 , and a conducting wire layer  25  are formed on the plastic layer  22  in sequence. The electrode layer  23 , the insulating layer  24 , and the conducting wire layer  25  constitute a touch layer of the present embodiment. The motherboard  20 , the plastic layer  22 , and the touch layer ( 23 ,  24 ,  25 ) form a touch assembly, wherein the touch layer ( 23 ,  24 ,  25 ) comprises a plurality of touch units. 
         [0057]    In one embodiment of the present disclosure, a passivation layer  26  can also be formed on the conducting wire layer  25 , which can not only protect the electrode layer  23 , the insulating layer  24 , and the conducting wire layer  25  from damage but can also prevent them from getting oxidized or corroded. 
         [0058]    Further, a release layer  210  can also be formed between the motherboard  20  and the plastic layer  22 , and a buffer layer  220  can also be formed between the plastic layer  22  and the electrode layer  23 . 
         [0059]    Further, referring to  FIG. 4B , the touch assembly can be cut so that each touch unit forms an independent touch sub-assembly. Comparing with the conventional method of manufacturing one unit by oue unit, the present embodiment firstly forms a plurality of touch units and then cuts them, which contributes to increasing possibility of mass production of the touch-on-lens (TOL) device and to enhancing productivity. 
         [0060]    In an embodiment, before or after forming the stack structure shown in  FIG. 4B , a strengthened lens  27  can additionally be provided, as shown in  FIG. 4C . A mask layer  28  can be formed under the strengthened lens  27 . 
         [0061]    Referring to  FIG. 4D , for forming the structures of the touch sub-assembly (as shown in  FIG. 4B ) and the strengthened lens  27  (as shown in  FIG. 4C ), an adhesive layer  29  can be used for gluing the two structures together; namely, the upper surface of the adhesive layer  29  can be glued to the lower surfaces of the strengthened lens  27  and the mask layer  28 , and the lower surface of the adhesive layer  29  can be glued to the upper surface of the passivation layer  26 . If the passivation layer  26  is not formed, the lower surface of the adhesive layer  29  can be glued to the upper surface of the touch layer ( 23 ,  24 ,  25 ). After gluing, the stack structure shown in  FIG. 4E , is formed, wherein the structure from bottom to top comprises a motherboard  20 , a release layer  210 , a plastic layer  22 , a buffer layer  220 , an electrode layer  23 , an insulating layer  24 , a conducting wire layer  25 , a passivation layer  26 , an adhesive layer  29 , a mask layer  28 , and a strengthened lens  27 . 
         [0062]    Further, the motherboard  20  is separated from the structure as shown in  FIG. 4E , forming the structure as shown in  FIG. 4F . 
         [0063]    According to the above manufacturing method, a touch-on-lens device can be formed. Referring to  FIG. 4F , the touch device comprises a strengthened lens  27  and a touch module ( 22 ,  220 ,  23 ,  24 ,  25 ,  26 ), wherein the touch module is laminated to the strengthened lens  27 . The touch module is formed by cutting a touch film that comprises a touch layer ( 23 ,  24 ,  25 ) and a plastic layer  22 , wherein thickness of the plastic layer is less than 25 μm. 
         [0064]    In one embodiment of the present disclosure, the plastic layer is a polyimide (PI) layer or a polyesterimide layer; the plastic layer is high-temperature resistant with good optical characteristics, and its thickness can be controlled within a comparatively thin scope. In a preferred embodiment, thickness of the plastic layer  22  is 10-20 μm. In a more preferred embodiment, thickness of the plastic layer  22  is 0.5-10 μm. Comparing with other plastic layers, such as PET, using the plastic layer can further make the touch-on-lens device thinner. 
         [0065]    Although the present disclosure has been described with reference to the embodiments thereof and best modes for carrying out the present disclosure, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present disclosure, which is intended to be defined by the appended claims.