Abstract:
An apparatus is provided. The apparatus comprises a second layer disposed over a first layer. Each of the first and second layers have a set of detection electrodes that are spaced apart and electrically isolated from one another and an associated set of interleavers. Each interleaver is located between adjacent detection electrodes from its associated the set of detection electrodes, and each set of interleavers also includes a pair of complementary interleaving electrodes coupled to those that are electrically coupled to the adjacent detection electrodes from its associated set of detection electrodes. The detection electrodes and interleaving electrodes are also substantially transparent to visible spectrum light.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates generally to a touch panel and, more particularly, to a capacitive touch panel having an improved response. 
       BACKGROUND 
       [0002]    Turning to  FIGS. 1 and 2 , an example of a conventional system  100  can be seen. System  100  generally comprises a touch panel  102  and touch panel controller  104 . The touch panel  102  has an array of sensors formed by a set of column electrodes (e.g., electrode  103 ), where each electrode of each column is coupled together by a strip electrode (e.g., strip electrode  107 ), and a set of row electrodes (e.g., electrode  109 ), where each electrode of each row is coupled together by a strip electrode (e.g., strip electrode  107 ). Usually, the column and row electrodes (e.g., electrodes  103  and  105 ) are formed in two separate layers with a dielectric or insulating layer formed therebetween, and these conductive layers which form the electrodes (e.g., electrodes  105  and  109 ) are generally transparent to visible spectrum light (e.g., light having a wavelength from about 380 nm to about 750 nm). The strip electrodes for each column (e.g., strip electrode  107 ) are then coupled to the interface or I/F  106  of the touch panel controller  104  by terminals X- 1  to X-N, while the strip electrodes for each row (e.g., strip electrode  109 ) are coupled to the interface  106  by terminals Y- 1  to Y-M. The interface  106  is able to communicate with the control circuit  108 . As shown in greater detail in  FIG. 2 , the interface  106  is generally comprised of a multiplexer or mux  202  and an exciter  204 . 
         [0003]    In operation, the interface  106  (which is usually controlled by the control circuit  108 ) selects and excites columns of electrodes (e.g., electrode  103 ) and “scans through” the rows of row electrodes (e.g., electrode  105 ) so that a touch position from a touch event can be resolved. As an example, interface  204  can excite two adjacent columns through terminals X-j and X-(j+1) with excitation signals EXCITE[j] and EXCITE[j+1], and interface  106  receives a measurement signal from a row associated with terminal Y-i. When an object (e.g., finger) is in proximity to the touch panel (which is generally considered to be a touch event), there is a change in capacitance due at least in part to the arrangement of electrodes (e.g., electrodes  103  and  105 ), and the controller  108  is able to resolve the position of the touch event. 
         [0004]    Most conventional touch panels (e.g., touch panel  102 ) do, however, exhibit a non-uniform response characteristic, which is manifested as non-uniform signal strength across the panel. This non-uniformity is generally caused by natural variations in the patterns forming the column and row electrodes (e.g., electrodes  103  and  105 ). In other words, the electrodes are arranged to have gaps or non-overlapping regions between the electrodes so that, as an object (e.g., finger) traverses the panel (e.g., panel  102 ) and passes over these non-overlapping regions, the signal strength or measured capacitance changes. Therefore, there is a need for a touch panel having a more uniform response characteristic. 
         [0005]    Some examples of other conventional systems are: U.S. Patent Pre-Grant Publ. No. 2011/0095996; U.S. Patent Pre-Grant Publ. No. 2011/0095997; U.S. Patent Pre-Grant Publ. No. 2011/0102361; and U.S. Patent Pre-Grant Publ. No. 2011/0157079. 
       SUMMARY 
       [0006]    An embodiment of the present invention, accordingly, provides an apparatus. The apparatus comprises a first layer having: a first set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the first set of detection electrodes is substantially transparent to visible spectrum light; and a first set of interleavers, wherein each interleaver from the first set of interleavers is located between adjacent detection electrodes from the first set of detection electrodes, and wherein each interleaver from the first set of interleavers includes: a first set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the first set of interleaving electrodes is substantially transparent to visible spectrum light; and a second set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the second set of interleaving electrodes is substantially transparent to visible spectrum light; and a second layer that is disposed over the first layer, wherein the second layer has: a second set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the second set of detection electrodes is substantially transparent to visible spectrum light; and a second set of interleavers, wherein each interleaver from the second set of interleavers is located between adjacent detection electrodes from the second set of detection electrodes, and wherein each interleaver from the second set of interleavers includes: a third set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the third set of interleaving electrodes is substantially transparent to visible spectrum light; and a fourth set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the fourth set of interleaving electrodes is substantially transparent to visible spectrum light. 
         [0007]    In accordance with an embodiment of the present invention, the first layer further comprises: a substrate that is substantially transparent to visible spectrum light; a conductive layer disposed over the substrate, wherein the conductive layer is patterned to form the first sets of detection electrodes and interleavers; and an insulating layer disposed over the conductive layer. 
         [0008]    In accordance with an embodiment of the present invention, the conductive layer further comprises a first conductive layer, and wherein the insulating layer further comprises a first insulating layer, and wherein the second layer further comprises: a second conductive layer disposed over the first layer, wherein the second conductive layer is patterned to form the second sets of detection electrodes and interleavers; and a second insulating layer disposed over the conductive layer. 
         [0009]    In accordance with an embodiment of the present invention, the first set of detection electrodes further comprises a first set of strip electrodes that are substantially parallel with one another and are oriented in a first direction, and wherein the second set of detection electrodes further comprises a second set of strip electrodes that are substantially parallel to one another and oriented in a second direction, and wherein the orientation of the first and second sets of strip electrodes with respect to one another forms a plurality of non-overlapping zones. 
         [0010]    In accordance with an embodiment of the present invention, the first direction is substantially perpendicular to the second direction. 
         [0011]    In accordance with an embodiment of the present invention, complementary pairs of interleaving electrodes from at least one of the first and second sets of interleaving electrodes and the third and fourth sets of interleaving electrodes are located in each non-overlapping zone. 
         [0012]    In accordance with an embodiment of the present invention, each interleaving electrode is substantially rectangular in shape. 
         [0013]    In accordance with an embodiment of the present invention, each interleaving electrode is substantially triangular in shape. 
         [0014]    In accordance with an embodiment of the present invention, the first and second sets of strip electrodes further comprise first and second sets of linear strip electrodes. 
         [0015]    In accordance with an embodiment of the present invention, the first and second sets of strip electrodes further comprise first and second sets of diamond strip electrodes. 
         [0016]    In accordance with an embodiment of the present invention, the complementary pairs of interleaving electrodes from the first and second sets of interleaving electrodes and from the third and fourth sets of interleaving electrodes are located in each non-overlapping zone. 
         [0017]    In accordance with an embodiment of the present invention, an apparatus is provided. The apparatus comprises a touch panel screen having a touch sensor disposed over a display, wherein the touch sensor has: a first layer having: a first set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the first set of detection electrodes is substantially transparent to visible spectrum light; and a first set of interleavers, wherein each interleaver from the first set of interleavers is located between adjacent detection electrodes from the first set of detection electrodes, and wherein each interleaver from the first set of interleavers includes: a first set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the first set of interleaving electrodes is substantially transparent to visible spectrum light; and a second set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the second set of interleaving electrodes is substantially transparent to visible spectrum light; and a second layer that is disposed over the first layer, wherein the second layer has: a second set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the second set of detection electrodes is substantially transparent to visible spectrum light; and a second set of interleavers, wherein each interleaver from the second set of interleavers is located between adjacent detection electrodes from the second set of detection electrodes, and wherein each interleaver from the second set of interleavers includes: a third set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the third set of interleaving electrodes is substantially transparent to visible spectrum light; and a fourth set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the fourth set of interleaving electrodes is substantially transparent to visible spectrum light; and a touch panel controller that is electrically coupled to the first and second sets of detection electrodes. 
         [0018]    In accordance with the present invention, the first set of interleaving electrodes form a first set of first serpentines with its detection electrodes, and wherein the second set of interleaving electrodes form a second set of serpentines with its detection electrodes, and wherein each first serpentine is interleaved with at least one second serpentine. 
         [0019]    In accordance with the present invention, the third and forth interleaving electrodes form a zig-zag pattern the overlaps the interleaved first and second serpentines. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0021]      FIGS. 1 and 2  are diagrams of an example of a conventional system; 
           [0022]      FIG. 3  is a diagram of an example of a system in accordance with the present invention; 
           [0023]      FIG. 4  is a cross-sectional view of a touch panel of  FIG. 3  along section line I-I; 
           [0024]      FIGS. 5 and 6  are plan views of portions of the section of the touch panel depicted in  FIG. 4 ; and 
           [0025]      FIGS. 7-20  are examples of the plan views shown in  FIGS. 5 and 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Refer now to the drawings wherein depicted elements are, for the sake of clarity, not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views. 
         [0027]    Turning to  FIG. 3 , an example of a system  200  in accordance with an embodiment of the present invention can be seen. System  200  is similar in construction to system  100  except that touch panel  102  has been replaced by touch panel  202 . Additionally, interconnect  204  has been provided to provide communication channels between the touch panel controller  104  and the touch panel  202 . 
         [0028]    In  FIG. 4 , a cross sectional view for section  206  of touch panel can be seen. As shown in this example, the touch panel  202  is generally comprised of a touch sensor  322  disposed over or positioned over a display  316  (which can, for example be a liquid crystal display or LCD) so as to allow the light from the display to project through the sensor  322 . This means that each layer of the sensor  322  is substantially transparent to visible spectrum light. As shown, the touch sensor  322  is a dual or two layer sensor, having a row layer  320 , column layer  318 , and cover plate  314 . The column and row layers  318  and  322 , in this example, each have a conductive layer  304  and  310  (respectively) disposed on a substrate  302  and  308  (respectively), but one of the substrates  302  or  308  may be used instead of two. Typically, the substrates  302  and  308  are formed of glass (which is substantially transparent to visible spectrum light), and the conductive layers  310  and  304  are usually formed of a conductive material that is generally transparent to visible spectrum light (such as indium tin oxide, aluminum doped zinc oxide, gallium doped zinc oxide, or indium doped zinc oxide). Conductive layers  304  and  310  are also usually formed by electron beam evaporation, physical vapor deposition (PVD), or sputter deposition on the substrates  302  and  308 , which can, for example, then be patterned using laser ablation or etching so to form the detection electrodes. The row and column layers  320  and  318  can then be secured to one another and the cover plate  314 , using an insulating or dielectric material (which can be an adhesive, like epoxy). 
         [0029]    In order to achieve a more uniform response characteristic for the touch sensor  322 , the patterns for the conductors  304  and  310  should be modified. As shown in the example of  FIGS. 5 and 6 , row and column interleavers  404  and  504  (respectively) are introduced between adjacent rows (e.g., rows  402 - 1  and  402 - 2 ) and adjacent columns (e.g., columns  502 - 1  and  502 - 2 ) across the touch sensor  322 . The interleavers (e.g.,  404  and  504 ) can vary in configuration based on the shape or configuration of the conductors  304  and  310  but are intended to reduce the size (and, thus, the impact) of the non-overlapping zones and produce a generally uniform response characteristic across the touch sensor  322 . 
         [0030]    In  FIGS. 7-9 , an example of an arrangement for the row and column interleavers  404  and  504  is shown (which are labeled  404 -A and  504 -A, respectively) for section  206 -A. In this example, row electrodes  402 -A 1  and  402 -A 2  are combined with row interleaver  404 -A so as to form serpentine electrodes that are interleaved with one another. The row layer  320 -A can also (optionally) include floating regions (e.g., floating region  406 ) interspersed between sections of the row interleaver  404 -A, which can improve optical characteristics and response of the sensor (e.g.,  322 ). Overlapping the row electrodes  402 -A 1  and  402 -A 2  and row interleaver  404 -A are the column electrodes  502 -A 1  and  502 -A 2  and column interleaver  504 -A that are arranged in a zig-zag or “fishbone” pattern. 
         [0031]    Turning to  FIGS. 10-12 , another example of an arrangement for the row and column interleavers  404  and  504  (which are labeled  404 -B and  504 -B, respectively) for section  206  (which is labeled  206 -B) can be seen. For this example, column electrodes  502 -B 1  and  502 -B 2  and row electrodes  402 -B 1  and  402 -B 2  are linear strip conductors that are oriented in different directions so as to be perpendicular to one another. Because linear strip electrodes are employed, the non-overlapping region  602 -B is large. So, the row and column interleavers  404 -A and  502 -A are each formed of complementary pairs of interleaving electrodes that are each electrically coupled to a corresponding electrode (e.g.,  402 -A 1 ) and that extend into the non-overlapping region  602 -B. These complementary pairs of interleaving electrodes, however, remain electrically isolated from one another. By doing this, the effect that the non-overlapping region has on the performance of the touch sensor  322  can be greatly reduced. Alternatively, as shown in  FIGS. 13 and 14 , all of the complementary pairs of interleaving electrodes do not need to be within the non-overlapping region (as shown with region  602 -C), but some (e.g., interleaving electrodes for column interleaver  504 -C in column layer  318 -C) may be in proximity or substantially over/under corresponding electrodes (e.g., row electrode  402 - 1 ) in a staggered pattern. 
         [0032]    Additionally, as shown in  FIGS. 15-17 , the interleaving electrodes may take a variety of shapes. With section  206 -B and  206 -C (which are described above), the interleaving electrodes are substantially rectangular in shape, but it may be advantageous to employ other shapes. In the example shown in  FIGS. 15-17 , row interleaver  404 -D and column interleaver  504 -D employ triangular shaped interleaving electrodes. 
         [0033]    The interleaving electrodes may also be employed with various detection electrode shapes as well. In the example shown in  FIGS. 18-20 , the column electrodes  502 -E 1  and  502 -E 2  and row electrodes  402 -E 1  and  402 -E 2  are arranged as diamond strip electrodes (similar to the configuration shown with touch panel  102 ) that are oriented in different directions so as to be perpendicular to one another. In this example, the interleaving electrodes for the column interleaver  504 -E and row interleaver  404 -E are positioned on the edges of the diamonds in the column electrodes  502 -E 1  and  502 -E 2  and row electrodes  402 -E 1  and  402 -E 2 . This allows the performance of a touch sensor  322  with good response characteristics (e.g., use of diamond strip electrodes) can be further improved. 
         [0034]    Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.