Patent Publication Number: US-8125454-B2

Title: Resistive type touch panel

Description:
PRIORITY CLAIM 
     This application claims the benefit of the Korean Application No. P2003-83690 filed on Nov. 24, 2003, which is hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a touch panel, and more particularly, to a resistive type touch panel that is configured to distinguish between inadvertent contact with the touch panel and desired selection of a displayed item. 
     2. Related Art 
     Touch panels are widely integrated with display surfaces of display devices such as electronic calculators, liquid crystal display (LCD) devices, plasma display panel (PDP) devices, electroluminescence (EL) devices, and cathode ray tubes (CRTs). Touch panels may be classified into an analog resistive type, a capacitive type, and an EM (Electro-magnetic) type. In general, touch panels are capable of sensing the location on the display surface where a user contacts the display surface with an object such as a pen, a finger, etc. Contact with the display surface results in the generation of a location specific input signal. Based on the information currently displayed, and the particular location where the display surface was touched by the user, the input signal may be converted to input data, such as an input instruction to direct the operation of a computer device. In some applications, a touch screen may be used in place of remote controllers or other input devices that are external to the display device. For example, using a touch panel integrated into a display device, a user may select desired information with a pen or a hand while observing an image displayed by the display device. 
     Generally, touch panels are provided with upper and lower transparent substrates, each having electrodes formed thereon. The upper and lower transparent substrates may be bonded to each other within a predetermined space. If a surface of the upper transparent substrate is touched at a predetermined point using input means, e.g., a finger, a pen, etc., the electrode formed on the upper transparent substrate electrically connects to the electrode formed on the lower transparent substrate. A voltage, made variable by a resistance value or a capacitance value of the touched point, is then detected and outputted along with a location defined by coordinates of the touched point. 
     In a capacitive type touch panel, a film having a transparent electrode is formed on an LCD panel. A voltage applied to each corner of the film generates a uniform electric field in the transparent electrode. Thus, a voltage drop is generated when a predetermined point of a display surface is touched with an input means such as finger or conductive stylus, thereby detecting coordinates of the touched point. 
       FIG. 1  is a schematic view illustrating a resistive type touch panel device according to the related art. As shown in  FIG. 1 , the touch panel device includes a touch panel  10 , a touch panel controller  30 , and a system  40 . The touch panel  10  outputs a coordinate signal representative of a touched point on a display. The touch panel controller  30  drives the touch panel  10 . In addition, the touch panel controller  30  determines coordinates according to the coordinate signal provided by the touch panel  10 . The touch panel controller  30  also outputs the value of the coordinates to the system  40 . In response to the value of the coordinates from the touch panel controller  30 , the system  40  may perform a corresponding command. 
     The touch panel  10  includes an upper film  12  and a lower film  16 . A first transparent conductive layer  14  is formed on a lower surface of the upper film  12 , and a second transparent conductive layer  18  is formed on an upper surface of the lower film  16 . An adhesive may be used to bond the upper film  12  and the lower film  16 . The adhesive may be applied to a peripheral area of the upper and lower films  16  that is a non-touch area. When bonded, a predetermined distance is maintained between the upper film  12  and the lower film  16 . The predetermined distance corresponds to a thickness of the adhesive  22 . 
     Prior to bonding, a plurality of dot spacers  20  are formed on the first transparent conductive layer  14  of the upper film  12  or the second transparent conductive layer  18  of the lower film  16 . The dot spacers  20  maintain the predetermined distance between the upper film  12  and the lower film  16  during and following bonding. The dot spacers  20  are disposed in a touch area of the upper film  12 . As previously discussed, the upper film  12  is subject to touching by a user with, for example a pen or finger. 
     The upper film  12  may be formed of a transparent film such as a Polyethylene Terephtalate (PET) film. The lower film  16  may also be formed of a transparent film, such as a glass substrate or a plastic substrate of the same material as the upper film  12 . The first and second transparent conductive layers  14  and  18  may be formed of a conductive material such as Indium-Tin-Oxide (ITO), Indium-Zinc-Oxide (IZO) and Indium-Tin-Zinc-Oxide (ITZO). 
     The illustrated touch panel  10  includes an X-electrode bar  15  and a Y-electrode bar  19 . The X-electrode bar  15  is in contact with the first transparent conductive layer  14  to apply a voltage to the first transparent conductive layer  14  according to an X-axis direction. The Y-electrode bar  19  is in contact with the second transparent conductive layer  18  to apply a voltage to the second transparent conductive layer  18  according to a Y-axis direction. The X-electrode bar  15  includes a first X-electrode bar  15   a  for applying a driving voltage Vcc to form a current according to the X-axis direction, and a second X-electrode bar  15   b  for applying a ground voltage GND. The Y-electrode bar  19  includes a first Y-electrode bar  19   a  for applying a driving voltage Vcc to form a current according to the Y-axis direction, and a second Y-electrode bar  19   b  for applying a ground voltage GND. 
     During operation, when the upper film  12  of the touch panel  10  is touched with a pen or a finger, the first transparent conductive layer  14  is brought into contact with the second transparent conductive layer  18 . In response to the contact, a resistance value is varied at the touching point according to a surface resistance of the first and second transparent conductive layers  14  and  18 . As a result, the current or the voltage is varied according to the varied resistance value. The varied voltage or current may provide the X-axis coordinate signal. The X-axis coordinate signal is output through the first or second Y-electrode bar  19   a  or  19   b  that is in contact with the second transparent conductive layer  18 . Alternatively, the varied voltage or current may provide the Y-axis coordinate signal. The Y-axis coordinate signal is output through the first or second X-electrode bar  15   a  or  15   b  that is in contact with the first transparent conductive layer  14 . In the illustrated example, the touch panel  10  may sequentially output the X-axis coordinate signal and the Y-axis coordinate signal under control of the touch panel controller  30 . 
     Specifically, the driving voltage Vcc and the ground voltage GND may be provided to the X-electrode bar  15  through a first switch  24  included in the touch panel  10 . In response to the varied resistance value in the touching point of the first and second transparent conductive layers  14  and  18 , the X-axis coordinate signal may be output through the second Y-electrode bar  19   b  and a second switch  26  included in the touch panel  10 . On the other hand, the driving voltage Vcc and the ground voltage GND may be provided to the Y-electrode bar  19  through the first and second switches  24  and  26 . In response to the varied resistance value at the touching point of the first and second transparent conductive layers  14  and  18 , the Y-axis coordinate signal may be output through the second X-electrode bar  15   b.    
     The first switch  24  provides the driving voltage Vcc to the first X-electrode bar  15   a  or the first Y-electrode bar  19   a  in response to a control signal CS from the touch panel controller  30 . The second switch  26  outputs the voltage of the touching point or provides the ground voltage GND to the second X-electrode bar  15   b  or the second Y-electrode bar  19   b  in response to the control signal CS of the touch panel controller  30 . The touch panel controller  30  detects the X-Y coordinate value of the touching point output from the touch panel  10 , and provides the X-Y coordinates to the system  40 . As a result, the touch panel controller  30  controls the first and second switches  24  and  26  according to an X-axis coordinate mode and a Y-axis coordinate mode, and provides power source (Vcc and GND) for the touch panel  10 . 
     The touch panel controller  30  includes an analog-digital converter (hereinafter, referred to as ADC)  32 , a micom  34  and an interface  36 . The ADC  32  converts the X-axis and Y-axis coordinate signals to digital data. The micom  34  detects the coordinate value by combining the X-axis and Y-axis coordinate data. In addition, the micom  34  outputs the coordinate value to the interface  36 . The interface  36  provides the coordinate value to the system  40 . 
     When the coordinate values are provided sequentially by the touch panel  10 , the ADC  32  converts the X-axis coordinate signal and the Y-axis coordinate signal to digital data, and then outputs the digital data. The micom  34  combines the X-axis coordinate data and the Y-axis coordinate data sequentially provided from the ADC  32  to detect the coordinate value of the touching point. The coordinate value detected by the micom  34  is provided to the system  40  through the interface  36 . The micom  34  may also periodically generate the control signal CS to control the operation of the first switch  24  and the second switch  26 . 
     The system  40  detects the coordinate value from the touch panel controller  30  and may perform a corresponding command or an applied program. The system  40  also provides a power source signal and video data for the display. Thus, the touch panel device detects the coordinate value touched by a pen or a finger, transmits the coordinate value to the system  40 , and the system  40  performs the corresponding command according to the coordinate value. 
     However, when the upper film  12  is inadvertently touched with a pen and a finger at the same time by a user, a double touch may be generated.  FIG. 2  is an equivalent circuit diagram of the touch panel of  FIG. 1 . As shown in  FIG. 2 , if the pen (finger) is touched at a predetermined point on a resistive type touch panel, voltage values for the X-axis and Y-axis of the predetermined point are obtained as follows.
 
 X -axis voltage( V )= E×{RX 2/( RX 1 +RX 2)}
 
 Y -axis voltage( V )= E×{RY 2/( RY 1+ RY 2)}
 
     At this time, ‘E’ may be an applied voltage such as 5V or 3.3V, ‘RX1+RX2’ is a resistance of a contact portion with the upper substrate, and ‘RY1+RY2’ is a resistance of a contact portion with the lower substrate. 
       FIG. 3  is a perspective view of dot spacers disposed on one substrate of the resistive type touch panel according to the related art. As shown in  FIG. 3 , the plurality of dot spacers  20  are printed and disposed on the upper film  12  or the lower film  16  at fixed intervals in a resistive type touch panel.  FIG. 3  shows the dot spacers  20  formed on the lower film  16 . The dot spacers  20  are formed of a UV (ultraviolet rays) curing ink type material. The center-to-center distance (Lp) between the dot spacers is ‘Lp=2 mm’. Also, the dot spacer  20  is generally formed as a spherical shape. Typically, the dot spacer  20  is formed of a distorted spherical shape in which a horizontal length ‘Ld’ ( FIG. 4 ) is relatively longer than a vertical height (not illustrated) of the dot spacer  20 . For example, the dot spacer  20  has a horizontal length of about 80 μm. 
       FIG. 4  illustrates an example of a double touch that occurs by touching a pen and a portion of a user&#39;s hand on the touch panel at the same time. As shown in  FIG. 4 , the user may touch the touch panel  10  (upper film  12 ) with the pen and the hand at the same time when the user inputs letters or draws pictures with the pen. In this case, the double touch is detected on the touch panel  10 . That is, two touch points of both a pen touch point (T 1 ) and a hand touch point (T 2 ) are generated on the touch panel  10 . The pen touch point (T 1 ) and the hand touch point (T 2 ) may be generated by the touch panel  10  at the same time, or sequentially at a predetermined interval. 
     If the pen touch point (T 1 ) and the hand touch point (T 2 ) are generated at the same time, the touch panel  10  generates the coordinate signal of a middle point between the pen touch point (T 1 ) and the hand touch point (T 2 ). As a result, the touch panel controller  30  and the system  40  utilize the middle point and thereby generate an error in detecting the pen touch point (T 1 ). If the hand touch point (T 2 ) is generated after the pen touch point (T 1 ) within a predetermined interval, the touch panel  10  generates a first coordinate signal for the pen touch point (T 1 ), and then a second coordinate signal for a middle point between the pen touch point (T 1 ) and the hand touch point (T 2 ). If both the first and second coordinate signals are generated within the predetermined interval, such as a 3.4 ms time period, the touch panel controller  30  detects the coordinate value for the second coordinate signal (the middle point), and then provides the same to the system  40 . In response, the system  40  generates an error by detecting the middle point as the pen touch point (T 1 ). 
       FIG. 5  is an equivalent circuit diagram of the example double touch in the resistive type touch panel of  FIG. 4 . As shown in  FIG. 5 , if the double touch of the pen and hand touch points (T 1  and T 2 ) are detected together, the middle voltage value of the pen and hand touch points (T 1  and T 2 ) is detected as the pen touch point (T 1 ). Electrically, when two points are touched by the pen and the hand, the same resistance R2 is connected between the two points in parallel. For example, supposing that the double touch occurs when 5V (Vcc) is applied to one side of the X-axis or Y-axis electrode bar, and the other side is grounded. At this time, the voltage value of the pen touch point (T 1 ) is, 
     
       
         
           
             
               
                 
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     In this scenario, the voltage signal of the point having the resistance value (R2/2) between the pen and hand touch points (T 1  and T 2 ) is transmitted to the touch panel controller  30  and an undesired coordinate value is generated. Accordingly, there is a need for resistive type touch panels capable of differentiating between actual touches and inadvertent touches. 
     SUMMARY 
     A resistive type touch panel includes a display screen having a first substrate and a second substrate. Each of the first and second substrates includes a transparent conductive layer that is on facing surfaces of the first and second substrates. The first substrate may include a first conductive layer and the second substrate may include a second conductive layer. Disposed between the first and second substrates is a plurality of spacers. 
     The spacers are designed and positioned between the first and second substrates to avoid inadvertent contact between the first and second conductive layers when the first substrate is deformed during operational use of the touch screen. During operation, touching the display screen with an activation force may cause deformation of the first substrate resulting in contact between first and second conductive layers. Contact between the first and second conductive layers results in the generation of coordinates indicative of the location that the display screen was touched. By minimizing inadvertent contact, generation of erroneous coordinate information can be minimized. 
     Distinguishing the difference between a desired touch and an inadvertent touch may be realized using the spacers. The geometry and positioning of the spacers selectively allows contact between the first and second conductive layers depending on the surface area of the substrate to which the activation force is applied. A concentrated activation force applied with objects having a relatively small surface area, such as a pen, will result in the generation of coordinate location information. Conversely, an activation force applied with an object having a relatively large surface area, such as a portion of a users hand, will be distributed over a larger area of the substrate. Accordingly, a larger number of spacers will be subject to the activation force. As a result, the magnitude of deformation of the substrate will be lessened and contact between the first and second conductive layers may be avoided. 
     Each of the spacers may be a polygonal column shape such as a hexahedral shape. A first surface of each of the spacers may be positioned contiguous with the conductive layer included with the first substrate. A second surface of each of the spacers may be positioned proximate with the conductive layer included with the second substrate with a space there between. The first and second surfaces may contact the conductive layers when an activation force is applied to the substrate. In addition, each of the spacers may include a third surface perpendicular to the first and second surfaces. A plurality of edge spacers that are positioned adjacent to a periphery of the transparent conductive layers may also be included. The edge spacers may be formed with a hemispherical surface configured to be in contact with one of the transparent conductive layers. 
     Other systems, methods, features, and advantages of the invention will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the following claims. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The inventions can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the inventions. 
         FIG. 1  is a schematic view illustrating a resistive type touch panel according to the related art. 
         FIG. 2  illustrates an equivalent circuit diagram of the touch panel of  FIG. 1 . 
         FIG. 3  is a perspective view of dot spacers disposed on one substrate of a resistive type touch panel according to the related art. 
         FIG. 4  is a cross sectional view illustrating a double touch scenario involving a resistive type touch panel according to the related art. 
         FIG. 5  is an equivalent circuit diagram of a double touch scenario in a touch panel of  FIG. 4 . 
         FIG. 6  is a perspective view of a resistive type touch panel. 
         FIG. 7  is a cross sectional view along I-I′ of a portion of the resistive touch panel of  FIG. 6  according to a first embodiment; 
         FIG. 8  is a table of showing activation forces of a pen and a hand for different shapes and center-to-center distances of spacers for two kinds of film. 
         FIG. 9  is a cross sectional view along I-I′ of a portion of the resistive touch panel of  FIG. 6  according to a second embodiment. 
         FIG. 10  is a plan view showing an arrangement of spacers in a resistive type touch panel according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 6  is a perspective view of a resistive type touch panel according to the present invention. As shown in  FIG. 6 , the resistive type touch panel  100  includes an upper substrate  112  and a lower substrate  116 . A first transparent conductive layer  114  and a second transparent conductive layer  118  may be formed on facing surfaces of the upper substrate  112  and the lower substrate  116 , respectively. The upper substrate  112  is disposed at a predetermined interval or distance from the lower substrate  116 . 
     The upper and lower substrates  112  and  116  may be bonded to each other along a periphery area of the first and second transparent conductive layers  114  and  118 . The periphery area may also be referred to as a non-touch area. An adhesive layer may be used to bond the upper and lower substrates  112  and  116  together. The upper and lower substrates  112  and  116  are separated from each other at a distance corresponding to a thickness of the adhesive layer  122  within a touch area. 
     A plurality of spacers  120  are also included in the resistive type touch panel  100 . The spacers  120  may be disposed on the first transparent conductive layer  114  of the upper substrate  112  or the second transparent conductive layer  118  of the lower substrate  116  within the touch area. The spacers  120  may be disposed with equal spacing, or at the same intervals, within the touch area. 
     The spacers  120  may be formed in a polygonal column shape, such as a rectangular parallelepiped. As compared with dot spacers of a spherical shape, the spacers  120  formed with a polygonal column shape have a first surface, a second surface and a third surface. The first and second surfaces may lie in respective first and second planes that are substantially parallel with the first and second transparent conductive layers  114  and  118 , respectively. The first and second surfaces may be substantially equal in area and included a plurality of edges that meet at ninety degree angles to form a square within the respective first and second planes. The third surface may include one or more surfaces each lying in a separate single plane. Each of the one or more third surfaces is perpendicular to each of the first and second surfaces. 
     In the example illustrated in  FIG. 6 , each of the spacers  120  are illustrated as cuboids or rectangular parallelpipeds that include three pairs of rectangular faces placed opposite each other and joined at right angles with each other. In this example, the top and bottom of each of the rectangular parallelpipeds represent the first and second surfaces. In addition, one of the sides of the rectangular parallelpiped represents the third surface. In other examples, the spacers  120  may be formed as any polygonal column shape such as a triangular prism, a square pillar, or a pentagonal pillar. Since the spacers  120  are formed in the polygonal column shape, decreases in inadvertent touches may be realized by increasing the contact between the first and second surfaces of the spacers  120  and the upper substrate  112  during an activation force. 
     The first and second surfaces provide support for upper and lower substrates  112  and  116  when an activation force is applied. An activation force is applied to upper substrate  112  to select an object displayed on the resistive type touch panel. In response to the activation force, the upper substrate  112  will bend, warp, flex or otherwise move toward the lower substrate  116  in the area to which the activation force is applied. As a result, one or more of the first and second surfaces of the spacers  120  contact both the upper and lower substrates  112  and  116  at the same time. The number of spacers  120  contacting both the upper and lower substrates  112  and  116  is based on the area of the upper substrate  112  in which the activation force is applied. For example, an activation force applied to a relatively small area of the upper substrate  112  will cause fewer spacers  120  to contact both the upper and lower substrates  112  and  116 . Conversely, an activation force distributed over a larger area of the upper substrate  112  will cause larger numbers of spacers  120  to contact with both the upper and lower substrates  112  and  116 . 
     The amount of deformation or displacement of upper substrate  112  in response to an activation force is based on the number of spacers  120  contacting both the upper and lower substrates  112  and  116 . In other words, an area of the upper substrate  112  subject to an activation force will experience deformation that is proportional to the quantity of the first or second surfaces of the spacers  120  supporting that area of the upper substrate  112 . An activation force concentrated in a relatively small area of the upper substrate  112  results in support by fewer spacers  120  and therefore a proportionally larger deformation of the upper substrate  112 . Conversely, the same activation force distributed over a relatively large area of the upper substrate  112  results in support by a larger number of spacers  120  and therefore proportionally less deformation of the upper substrate  112 . 
     Accordingly, for example, an activation force created by a hand touched on a large area, creates negligible displacement when compared to the displacement caused by the same magnitude of activation force created by a pen touched on a smaller area. Thus, an activation force of a hand must be relatively larger than an activation force of a pen to create similar deformation. 
     The upper substrate  112  may be formed of a transparent film such as a Polyethylene Terephtalate (PET) film. The lower substrate  116  may be formed of a transparent film, such as a glass substrate or a plastic substrate of the same material as the upper substrate  112 . The first and second transparent conductive layers  114  and  118  may be formed of Indium-Tin-Oxide (ITO), Indium-Zinc-Oxide (IZO) and Indium-Tin-Zinc-Oxide (ITZO) or any other material with conductive properties. 
     The touch panel  100  also includes an X-electrode bar  115  and a Y-electrode bar  119 . The X-electrode bar  115  may be in contact with both edges of the first transparent conductive layer  114  to apply a voltage to the first transparent conductive layer  114  along an X-axis direction. The Y-electrode bar  119  may be in contact with both sides of the second transparent conductive layer  118  to apply a voltage to the second transparent conductive layer  118  along a Y-axis direction. The X-electrode bar  115  may include a first X-electrode bar  115   a  for applying a driving voltage Vcc to flow a current in the first transparent conductive layer  114  along the X-axis direction, and a second X-electrode bar  115   b  for applying a ground voltage GND. The Y-electrode bar  119  may include a first Y-electrode bar  119   a  for applying a driving voltage Vcc to flow a current in the second transparent conductive layer  118  along the Y-axis direction, and a second Y-electrode bar  119   b  for applying a ground voltage GND. The spacers  120  may be disposed on the upper substrate  112  or the lower substrate  116  at fixed intervals. 
     During operation, when an activation force of sufficient magnitude is applied by touching the upper substrate  112 , the first transparent conductive layer  114  is moved into contact with the second transparent conductive layer  118 . As a result, a resistance value is varied in the area of the touching point according to a surface resistance of the first and second transparent conductive layers  114  and  118 . Due to the varied resistance, the current or the voltage is varied so that the X-axis coordinate signal is output through the first or second Y-electrode bar  119   a  or  119   b  being in contact with the second transparent conductive layer  118 , and the Y-axis coordinate signal is output through the first or second X-electrode bar  115   a  or  115   b  being in contact with the first transparent conductive layer  114 . In this example, the touch panel  100  sequentially outputs the X-axis coordinate signal and the Y-axis coordinate signal under control of a touch panel controller (not shown). In other examples, other methods such as parallel outputs of the coordinate signals are possible. In addition, any other methods and/or mechanisms for determining and providing one or more coordinate signals representative of a location of a touch on a resistive type touch panel are also possible in other examples. 
     The resistive type touch panel  100  includes a touch panel controller (not shown) and a system. The touch panel controller drives the touch panel  100 , detects the coordinates according to the coordinate signal of the touch panel  100 , and outputs the value of the coordinates to the system as previously discussed. In response to the value of the coordinates from the touch panel controller, the system may perform a corresponding command. In this case, signal lines connected to the X-electrode bar  115  and the Y-electrode bar  119  are connected with the touch panel controller (not shown), whereby the driving voltage is provided to the X-electrode bar  115  and the Y-electrode bar  119 . 
     First Embodiment 
       FIG. 7  is a cross sectional view along I-I′ of a portion of the resistive type touch panel illustrated in  FIG. 6  depicting a first embodiment. In  FIG. 7 , spacers  120  are disposed on an upper substrate  112  or a lower substrate  116 . The spacers  120  may be formed by printing or photo process. The spacers  120  may be disposed on an area of the touch panel with a predetermined center-to-center distance (Lp) between the spacers  120  such as between about 0.5 mm and 0.6 mm. As used herein, the term “about” should be construed to be plus and minus 10% of the measure value, or plus and minus 5% of the measured value unless otherwise indicated. 
     Each spacer  120  has a predetermined length (Ld) and a predetermined width. The width and the length may be substantially equal, such as between about 40 μm and 50 μm. In addition, each of the spacers  120  may have a predetermined height, such as between about 5 μm and 13 μm. Accordingly, the area of the first and second surface of each of the spacers  120  may be between about 3.8 and 8 times greater than the area of the third surface of each of the spacers  120 . 
     A first transparent conductive layer  114  may be formed on the upper substrate  112 . The first and second X-electrode bars  115   a  and  115   b  may be formed at the left and right sides of the first transparent conductive layer  114 . In  FIG. 7 , the first and second X-electrode bars  115   a  and  115   b  are not shown since the first and second X-electrode bars  115   a  and  115   b  are not formed on the line I-I′ of  FIG. 6 . A second transparent conductive layer  118  is formed on the lower substrate  116 . The first and second Y-electrode bars  119   a  and  119   b  may be formed at the left and right sides of the second transparent conductive layer  118 . An adhesive layer  122  may be formed along corresponding portions of the first transparent conductive layer  114  and the first and second Y-electrode bars  119   a  and  119   b . The portions where the adhesive layer  122  is formed may correspond to a non-pixel area of a display screen. 
       FIG. 8  is a table of example test results showing activation forces of a pen and a hand based on forming the shape of the spacers as either a spherical shape or a hexahedral shape and using two different kinds of film (or substrate). The activation forces shown is the amount force needed to make contact between the first and second transparent conductive layers. As used herein, an activation force is defined as a force created by touch within an area of a substrate. The area within which the activation force is applied varies with the kind of object being used to perform the touch, such as the variation in area between a pen and a hand. 
     In the example of  FIG. 8 , the touch panel may have a touched surface formed of an A-type film or a B-type film (or substrate). The A-type film and B-type film may be fabricated to have different levels of flexibility when subject to an activation force. As illustrated in the results of  FIG. 8 , with similar center-to-center spacing, and regardless of the kind of film, the spacer that is formed as a hexahedral shape provided a greater difference between the activation forces needed by a pen and a hand to make contact between the first and second transparent conductive layers. In addition, it is to be noted that regardless of the kind of film, the center-to-center spacing of 0.5 mm between the spacers formed in a hexahedral shape made the greatest difference between the activation forces by a pen and a hand. 
     In the case of the A-type film, when the center-to-center spacing between the spacers formed as a hexahedral shape was about 0.5 mm, the greatest difference between the activation forces by a pen and a hand were achieved. In this case, the activation force by the hand (2.5 kg) is six times greater than the activation force by the pen (357 g). Thus, when a double touch of hand and pen occurs, it is possible to ignore the touch by the hand since the pressure of detecting the touch by the hand is significantly greater than the pressure of detecting the touch by the pen. 
     When using the A-type film and the center-to-center spacing between the spacers formed in a hexahedral shape is about 0.7 mm, the activation force by the hand (265 g) is two times greater than the activation force by the pen (137 g). If using the spacers formed in a spherical shape with the same center-to-center spacing, the activation force by the hand (200 g) and the activation force by the pen (141 g) are much more similar. Thus, using the spacers formed in a hexahedral shape has a greater difference between the activation forces created by a hand and a pen, as compared with using the spacers formed in a spherical shape. Similar results are illustrated in  FIG. 8  with the B-type film. 
     The example test results clearly illustrate that when spacers formed in a hexahedral shape are used, there is significant difference between the activation forces applied by a hand and a pen. Based on the aforementioned experiments, it appears that the resistive type touch panel obtains the most significant differences in activation force between a hand and a pen when the center-to-center distance between spacers formed in a hexahedral shape is between about 0.5 mm and 0.6 mm. 
     In the previously discussed example resistive type touch panel, the shape of the spacer is a hexahedral shape instead of a spherical shape and the center-to-center spacing between the spacers is selected appropriately. Accordingly, it is possible to configure the resistive type touch panel to ignore the touch of a hand, having a relatively large contact area, while sensitively detecting the touch of pen, having relatively small contact area when the magnitude of activation force is the same in both cases. 
     Second Embodiment 
       FIG. 9  is a cross sectional view along I-I′ of a portion of the resistive type touch panel  100  illustrated in  FIG. 6 . In  FIG. 9 , spacers  120  are formed on an area of the lower substrate  116 . In addition, the lower substrate  116  includes a plurality of edge spacers  125  disposed adjacent to an X-electrode bar  115  or a Y-electrode bar  119 , and adjacent to a periphery of the conductive layers  116  and  118 . 
     The edge spacers  125  are formed to have a hemispherical surface. The hemispherical surface is formed to be in contact with one of the transparent conductive layers  116  and  118  when an activation force is applied. Absent an activation force, the hemispherical surface is positioned proximate one of the transparent conductive layers  116  and  118  with a space there between. With the exception of the edge spacers  125 , the resistive type touch panel according to the second embodiment has a similar structure to the resistive type touch panel discussed with reference to  FIGS. 6-8 . 
     The edge spacers  125  are positioned near the periphery of the first and second transparent conductive layers  114  and  118  since a polygonal column shape may not be necessary. Even though a user&#39;s hand touches the circumference of the touch panel, a user may put his palm on a system bezel or other structural support instead of the substrate. Accordingly, the edge spacers  125  may not experience the activation force provided by a users hand as compared with the spacers  120  positioned away from the periphery of the first and second transparent conductive layers  114  and  118 . Referring to  FIG. 9 , the edge spacers  125  are formed with a hemispherical upper surface having a gentle slope to avoid sharp edges contacting the substrate and/or conductive layers. 
     Third Embodiment 
       FIG. 10  is a plan view of a portion of a resistive type touch panel  100  showing a disposition of spacers according to the third embodiment. In the resistive type touch panel  100  shown in  FIG. 10 , a plurality of spacers  130  may be formed in polygonal column shape, such as a hexahedral shape. Accordingly, the spacers  130  may each have a substantially similar length (Ld) and width that is between about 40 μm and 50 μm, and a height of between about 5 μm and 13 μm. 
     The spacers  130  may be disposed on one of the first substrate and the second substrate as previously discussed. In addition, the spacers  130  may be distributed in a predetermined pattern so that the spacers  130  are staggered with respect to each other. Accordingly, portions of the predetermined pattern may be configured to resemble a diamond shape (a-b-c-d) as illustrated. 
     In  FIG. 10 , the spacers  130  can be grouped into groups of spacers forming a plurality of horizontal lines along a first axis. In a first horizontal line along the first axis, the group of spacers are disposed at fixed intervals to have a center-to-center spacing (Lp) of between about 0.5 mm and 0.6 mm. In a second horizontal line that is parallel with the first horizontal line along the first axis, each of the spacers  130  is positioned to be between two adjacent spacers  130  of the first horizontal line. In a third horizontal line along the first axis, the spacers  130  are disposed at positions that correspond to the position of spacers  130  in the first horizontal line. 
     In addition, the spacers  130  can be grouped into groups of spacers forming a plurality of vertical lines along a second axis that is perpendicular to the first axis. In the illustrated groups of spacers forming vertical lines along the second axis, center-to-center spacing between adjacently positioned spacers  130  is between about 1.0 mm and 1.2 mm. In other words, the center-to-center spacing between the spacers  130  forming the vertical lines is about twice the center-to-spacing between the spacers  130  forming the horizontal lines. Other than the center-to-center spacing discussed above, the resistive type touch panel according to the third embodiment has a similar structure to the resistive type touch panel according to the first and second embodiments. 
     As compared with the center-to-center spacing of the spacers describe with reference to  FIGS. 6 ,  7  and  9 , the center-to-center spacing of the spacers  130  of  FIG. 10  provide a more distributed contact area of the surfaces of the spacers  130  with the upper substrate  112 . Thus, support during activation forces is more robust in the resistive type touch panel  100  of  FIG. 10 . Accordingly, activation forces applied to a relatively large area can be of higher activation force than in the embodiments of  FIGS. 6 ,  7  and  9  due to the staggered positioning of the spacers  130 . In other words, the spacers of  130  will proportionally provide more support of the upper substrate during an activation force so that more activation force will be necessary to create contact between the first and second transparent conductive layers when the activation force is distribute over an area of the substrate. 
     In the previously discussed embodiments of the resistive type touch panel, the shape of the spacers is a polygonal column shape. The polygonal column shape includes first and second surfaces that provide for improved support during an activation force distributed over a relatively large area while still insuring accurate detection of an activation force distributed over a smaller area. In addition, the center-to-center spacing and locations of the spacers provide improved detection accuracy. Accordingly, an activation force inadvertently provided by the hand of a user is less likely to be detected, while an activation force purposefully provided with a pen is more likely to be detected. Thus, use of the spacers formed in a polygonal column shape and a provide a hand rejection function to avoid inadvertent touches. In addition, when the spacers are positioned to be staggered with respect to each other, support for distributed activation forces may be further improved without detrimentally affecting the sensitivity of concentrated activation forces. 
     While various embodiments of the invention have been described above, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible and within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the claims and their equivalents.