Patent Publication Number: US-2011064943-A1

Title: Conductive slice structure

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to a conductive slice structure, and more particularly to a conductive slice structure with a carbon nanotube layer. 
     2. Description of Related Art 
     Touch panels or touch screens are widely applied in electronic apparatuses, particularly in portable or hand-held electronic apparatuses, such as personal digital assistants (PDA) or mobile phones. Touch panels include resistive-types, capacitive-types, and/or the inclusion optical touch technologies. 
     Typical touch panels include conductive layers of indium tin oxide (ITO), also known as ITO touch panels. Touch panels include conductive layers of carbon nanotubes (CNT) or CNT touch panels are recently proposed.  FIG. 1  shows a cross-sectional view of a typical resistive-type CNT touch panel. The CNT touch panel includes an upper conductive slice structure including an upper substrate  10 A and an upper CNT layer  11 A, and a lower conductive slice structure including a lower substrate  10 B and a lower CNT layer  11 B. The upper and lower conductive slice structures are separated by spacers  12  and are bonded by sealant  13 . A liquid crystal display panel  14  and a backlight module  15  providing light source are beneath the lower substrate  10 B. During operation, the upper CNT layer  11 A and the lower CNT layer  11 B may contact each other, and the voltage value of a touch point may be changed when a finger or a stylus touches a touch point on the surface of the upper substrate 10 A. The coordinate of the touch point is determined through detecting the positions of voltage variation respectively. 
       FIG. 2  shows an enlarged cross-sectional view of upper or lower conductive slice structures. A conductive slice structure of a conventional CNT touch panel includes a substrate 10  and a CNT layer  11 . The CNT layer  11  is attached on the surface of the substrate 10  through an adhesive (not shown). 
     Since the CNT layer  11  is constituted by carbon nanotubes which have optical, physical, chemical or electrical characteristics different to the ITO conductive layer, the optical, physical, chemical or electrical characteristics of the conventional conductive slice structure shown in  FIG. 2  can be improved. 
     SUMMARY OF THE DISCLOSURE 
     According to the embodiments of the present disclosure, the conductive slice structure has a substrate, a carbon nanotube layer, and a function layer above or beneath the carbon nanotube layer. The function layer has at least one of the functions including anti-reflection, anti-smudge, anti-fingerprint, anti-glare, anti-Newton rings, anti-static, and anti-scratch. Thus the optical, physical, chemical or electrical characteristics of the conductive slice structure and the performance of display apparatuses with CNT touch panels or CNT conductive layers can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
         FIG. 1  shows a cross-sectional view of a typical resistive-type CNT touch panel. 
         FIG. 2  shows an enlarged cross-sectional view of upper or lower conductive slice structures. 
         FIGS. 3 ,  4  and  5  show various conductive slice structures of the first embodiment of the present disclosure. 
         FIGS. 6 ,  7  and  8  show various conductive slice structures of the second embodiment of the present disclosure. 
         FIGS. 9 and 10  show various conductive slice structures of the third embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The detailed description of the present disclosure will be discussed in the following embodiments, which are not intended to limit the scope of the present disclosure, but can be adapted for other applications. While drawings are illustrated in details, it is appreciated that the scale of each component may not be expressly exactly. 
     In the following discussed embodiments, the disclosed conductive slice structures can be applied in the CNT touch panel shown in  FIG. 1 . However, the disclosed conductive slice structures can also be applied in CNT touch panels or display apparatuses with a CNT conductive layer other than that shown in  FIG. 1 . 
       FIG. 3  shows a conductive slice structure of a first embodiment of the present disclosure. In this embodiment, the conductive slice structure includes a substrate  20 , a CNT layer  22 , and a first function layer  21 A between the substrate  20  and the CNT layer  22 . The substrate  20  includes a transparent insulating layer, and the transparent insulating layer is selected from one of the following materials or is a combination of portions of the following materials: Poly-Ethylene-Terephthalate (PET), Polycarbonate (PC), Poly-Methyl-Meth-Acrylate (PMMA), Polyvinylchloride (PVC), Triacetyl cellulose (TAC, and glass. The CNT layer  22  can be a carbon nanotube film, where the carbon nanotube film includes a conductive film conformation with porous and silk, grating or net structures manufactured by extending single-wall or multi-wall carbon nanotube single-axially or multi-axially. The carbon nanotube film has minimum electric impedance along the extending direction and maximum electric impedance perpendicular to the extending direction so as to form anisotropic impedance. 
     In this embodiment, the first function layer  21 A includes a layer or a plurality of layers formed by coating or thin film technologies. In one embodiment, the first function layer  21 A can be a low refractive layer  21  (LR layer). The refractive index of the low refractive layer  21  is constant and less than the refractive index of the substrate  20 , and is used as an anti-reflection layer (AR layer) to improve transparency or transmission coefficient. As shown in  FIG. 4 , in this embodiment, the refractive index of the low refractive layer  21  is less than about 1.49 and greater than about 1.2. The material of low refractive layer  21  includes organic or inorganic materials with fluorine or silicon. In this embodiment, the thickness of the low refractive layer  21  is in the range of about 0.05 to about 10 um. Since the CNT layer  22  is a porous conductive film, the refractive indexes of the CNT layer  22  and the substrate  20  do not match such that the light is easily reflected. The low refractive layer  21  of this embodiment decreases the reflected light. 
     In another embodiment, the first function layer  21 A includes the low refractive layer  21  mentioned above and a high refractive layer  23 . The refractive index of the high refractive layer  23  is constant, greater than the refractive index of the low refractive layer  21  and less than the refractive index of the substrate  20 . In one embodiment, the refractive index of the high refractive layer  23  is greater than about 1.55. The material of the high refractive layer  23  can be polymer materials with a high refractive index or inorganic materials with a high refractive index such as TiO2, ITO and aluminum implanted zinc oxide (AZO), etc. The combination of the high refractive layer  23  and the low refractive layer  21  forms an anti-reflection layer to prevent or decrease the light leakage loss resulting from reflection to improve transparency as shown in  FIG. 5 . 
     The first function layer  21 A can be an anti-smudge layer to prevent or decrease contaminants through the spaces between carbon nanotubes of the CNT layer  22  into the conductive slice structure. An anti-fingerprint layer similar to the anti-smudge layer is utilized to prevent or decrease pollutions of grease or water of fingerprint on the conductive slice structure. The materials of the anti-smudge or anti-fingerprint first function layer  21 A can be polymer materials with hydrophobic functional groups such as polymer materials with fluorine or silicon. 
     The first function layer  21 A can be an anti-glare layer or an anti-Newton rings layer to prevent or decrease glare and the decrease of contrast ratio resulting from scattering of light or high intensity light. The materials of anti-glare or anti-Newton rings layers of the first function layer  21 A can be layers with organic or inorganic particles (1-5 um) or layers with surface having micro structures formed by physical imprinting or chemical formation processes. 
     The first function layer  21 A can also be an anti-static layer. The materials of the anti-static layer include anti-static particles and resin or resin with low dielectric constant. 
     The first function layer  21 A can also be an anti-scratch layer or a high hardness layer to prevent or decrease the damages of the conductive slice structure caused by frequently contacts or collisions. The anti-scratch first function layer  21 A includes organic polymer harden layers with functional groups such as Poly-Methyl-Meth-Acrylate (PMMA), epoxy, Polyurethane etc., or inorganic silicon dioxide harden layers. 
     According to the first embodiment shown in  FIG. 3 , the first function layer  21 A is selected from one or more above-mentioned function layers, such as the anti-reflection layer, the anti-smudge layer, the anti-fingerprint layer, the anti-glare layer, the anti-Newton rings layer, the anti-static layer, and the anti-scratch layer. Thus the optical, physical, chemical or electrical characteristics of the conductive slice structure and the performance of display apparatuses with CNT touch panels or CNT conductive layers can be improved. The adhesion between the multiple layers of the first function layer  21 A, or the adhesion between the first function layer  21 A, the substrate  20 , and the CNT layer  22  are achieved through the adhesive of the first function layer  21 A or an additional adhesive. 
     In another embodiment, the first function layer  21 A is disposed on and contacts the CNT layer  22 , which means that the CNT layer  22  is between the first function layer  21 A and the substrate  20 . The thickness of the first function layer  21 A is limited to ensure that voltage values on the CNT layer  22  can be changed when the CNT layer  22  is pressed. The thickness of the first function layer  21 A is preferably in the range of about 2 um to about 0.05 um. 
       FIG. 6  shows a conductive slice structure of a second embodiment of the present disclosure. In this embodiment, the conductive slice structure includes a substrate  20 , a CNT layer  22 , a first function layer  21 A between the substrate  20  and the CNT layer  22 , and a second function layer  21 B disposed on a side of the substrate  20  against the first function layer  21 A. The second function layer  21 B can also be on a side of the CNT layer  22  against the substrate  20  as shown in  FIG. 7 . The CNT layer  22 , the first function layer  21 A, and the substrate  20  shown in  FIGS. 3A and 3B  are similar to those in the first embodiment, and thus the functions and materials of the CNT layer  22 , the first function layer  21 A, and the substrate  20  are not particularly described again. The difference between the first and second embodiments is the second function layer  21 B. The second function layer  21 B includes a layer or a plurality of layers formed by coating or thin film technologies. The second function layer  21 B is selected from one or more above-mentioned function layers, such as the anti-reflection layer, the anti-smudge layer, the anti-fingerprint layer, the anti-glare layer, the anti-Newton rings layer, the anti-static layer, and the anti-scratch layer. 
     In one embodiment, the second function layer  21 B can be a low refractive layer  21  to improve transparency or transmission coefficient as shown in  FIG. 8 . In this embodiment, the thickness of the low refractive layer  21  is in the range of about 0.05 to about 2 um. Since the second function layer  21 B in  FIG. 7  or the low refractive layer  21  in  FIG. 8  applied in CNT touch panels needs to face another CNT layer of another conductive slice structure, the thickness of the second function layer  21 B or the low refractive layer  21  is limited to less than a thickness such as less than about 2 um to ensure that the conductivity between the CNT layers  22  of the conductive slice structures, and voltage values on the CNT layer  22  can be changed when the CNT layer  22  is pressed. 
     According to the second embodiment shown in  FIG. 6 , the first function layer  21 A and the second function layer  21 B are respectively selected from one or more above-mentioned function layers, such as the anti-reflection layer, the anti-smudge layer, the anti-fingerprint layer, the anti-glare layer, the anti-Newton rings layer, the anti-static layer, and the anti-scratch layer. Thus the optical, physical, chemical or electrical characteristics of the conductive slice structure and the performance of display apparatuses with CNT touch panels or CNT conductive layers can be improved. 
       FIG. 9  shows a conductive slice structure of a third embodiment of the present disclosure. In this embodiment, the conductive slice structure includes a substrate  20 , a CNT layer  22 , a first function layer  21 A between the substrate  20  and the CNT layer  22 , a second function layer  21 B disposed on the side of the substrate  20  against the CNT layer  22 , and a third function layer  21 C on the side of the CNT layer  22  against the substrate  20 . The CNT layer  22 , the first function layer  21 A, the substrate  20 , and the second function layer  21 B are similar to those in the second embodiment, and thus the functions and materials of the CNT layer  22 , the first function layer  21 A, the substrate  20 , and the second function layer  21 B are not particularly described again. The difference between the second and third embodiments is the third function layer  21 C. The third function layer  21 C includes a layer or a plurality of layers formed by coating or thin film technologies. The third function layer  21 C is selected from one or more above-mentioned function layers, such as the anti-reflection layer, the anti-smudge layer, the anti-fingerprint layer, the anti-glare layer, the anti-Newton rings layer, the anti-static layer, and the anti-scratch layer. Since the first function layer  21 A is between other layers in this embodiment, functions of anti-smudge, anti-fingerprinting and anti-scratch are less necessary. 
     In one embodiment, the third function layer  21 C can be a low refractive layer  21  to improve transparency or transmission coefficient as shown in  FIG. 10 . In this embodiment, the thickness of the low refractive layer  21  is in the range of about 0.05 to about 2 um. Since the third function layer  21 C in  FIG. 9  or the low refractive layer  21  in  FIG. 10  faces another CNT layer of another conductive slice structure, the thickness of the third function layer  21 C or the low refractive layer  21  is limited to less than a thickness such as less than about 2 um to ensure that the conductivity between the CNT layers  22  of the conductive slice structures. 
     According to the third embodiment shown in  FIG. 9 , the first function layer  21 A, the second function layer  21 B, and the third function layer  21 C are respectively selected from one or more above-mentioned function layers, such as the anti-reflection layer, the anti-smudge layer, the anti-fingerprint layer, the anti-glare layer, the anti-Newton rings layer, the anti-static layer, and the anti-scratch layer. Thus the optical, physical, chemical or electrical characteristics of the conductive slice structure and the performance of display apparatuses with CNT touch panels or CNT conductive layers can be improved. 
     Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present disclosure, which is intended to be limited solely by the appended claims.