JP2011022788A - Touch position detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch position detection device which can be manufactured at a low cost and has a simple configuration. <P>SOLUTION: The touch position detection device 1 includes: a touch panel 2 having column lines LS1 to LSn and row lines LC1 to LCm; three-state buffers BS1 to BSn; three-state buffers BC1 to BCm; comparators CPC1 to CPCm for comparing a voltage input from one end of each of the row lines LC1 to LCm with a threshold voltage VC; comparators CPS1 to CPSn for comparing a voltage input from one end of each of the column lines LS1 to LSn with a threshold voltage VS; column line resistors RS1 to RSn; and row line resistors RC1 to RCm. Since voltages input to comparators CPC1 to CPCm and voltages input to comparators CPS1 to CPSn are fixed respectively independently of a contact position, it is unnecessary to change the threshold voltage VC and the threshold voltage VS. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a touch position detection device including a touch panel.

  There are two types of touch position detection devices including a touch panel, an analog type and a matrix type, both of which are practically used for normal input operations. The analog type touch panel is superior in durability and inexpensive as compared with the matrix type touch panel, and has an advantage that it can easily cope with fine touch input by a touch pen.

  FIG. 11 shows a schematic configuration of a touch position detection apparatus 101 using an analog touch panel. FIGS. 11A and 11B are perspective views showing a schematic configuration of the touch position detection apparatus 101. FIG. The touch position detection apparatus 101 includes a resistance film 102 and a resistance film 103 that are separated from each other. Opposite electrodes 104 a and 104 b are formed on the two opposing sides of the resistance film 102, and opposing electrodes 105 a and 105 b are formed on the two opposing sides of the resistance film 103. As shown in FIG. 11A, a reference voltage is applied between the counter electrode 104a and the counter electrode 104b. As shown in FIG. 11B, a reference voltage is also applied between the counter electrode 105a and the counter electrode 105b.

  As shown in FIG. 11C, the resistive film 102 and the resistive film 103 are short-circuited at the touch position. At this time, the reference voltage applied to the resistance film 102 is divided by the resistance film 103, and the divided voltage is detected by A / D conversion, whereby the coordinates in the X direction and the Y direction are determined from the magnitude of the detected voltage value. Identify the location.

  On the other hand, a matrix-type touch panel has a configuration in which a number of matrix switches are arranged on the touch panel and each matrix switch detects a touch input. For this reason, even when touch input is performed at a plurality of positions on the touch panel, the corresponding matrix switch detects the touch input, so that each position input by touch can be determined.

  Patent Document 1 discloses a touch position detection device that takes advantage of both an analog touch panel and a matrix touch panel.

  FIG. 12 is a plan view showing the configuration of the touch position detection device 201 described in Patent Document 1. As shown in FIG. The touch position detecting device 201 includes a plurality of strip-shaped resistive films 202 and a plurality of strip-shaped resistive films 203. The strip-shaped resistive films 202 and the strip-shaped resistive films 203 are orthogonal to each other. ing. A reference voltage is applied to both ends of each strip-shaped resistive film 202... And strip-shaped resistive film 203. Even when a plurality of regions 204 where the strip-shaped resistive films 202 and the strip-shaped resistive films 203 overlap are touched at the same time, they are touched unless the positional relationship between the touched regions 204 is as follows. Each position can be detected. That is, when each region is touched by three or more points, touching is performed except when the region 204 other than the one point is touched in both of the strip-shaped resistive films orthogonal to each other at one point. Each position can be detected.

  However, the touch position detection device 101 shown in FIG. 11 and the touch position detection device 201 shown in FIG. 12 have a problem that the configuration is complicated because it is necessary to apply a voltage from four directions of the touch panel. Therefore, a configuration has been proposed in which a touch position can be detected by applying a voltage from two directions of the touch panel (for example, Patent Document 2).

  FIG. 13 is a diagram illustrating a configuration of the touch position detection device 301 described in Patent Document 2. As illustrated in FIG. The touch position detection device 301 includes a touch panel 302, a column line driver 303, and a row line driver 304. The touch panel 302 includes n (n is an integer of 2 or more) column lines LS1 to LSn arranged in the row direction and m (m is an integer of 2 or more) row lines LC1 to LCm arranged in the column direction. And have. The column lines LS1 to LSn and the row lines LC1 to LCm are spaced apart and orthogonal to each other. In addition, one end of each column line LS1 to LSn is connected to the column line driver 303, and the other end is held by an insulator. Similarly, one end of each of the row lines LC1 to LCm is connected to the row line driver 304, and the other end is held by an insulator.

  The column line driver 303 includes n three-state buffers BS1 to BSn and n comparators CPS1 to CPSn. The input terminals of the three-state buffers BS1 to BSn are connected to the power supply Vcc. The output terminals of the three-state buffers BS1 to BSn are connected to one ends of the column lines LS1 to LSn via resistors Ra (resistance values 1 to 5 kΩ), respectively.

  The negative input terminal of each comparator CPS1 to CPSn is connected to one end of each column line LS1 to LSn. On the other hand, threshold voltages VS1 to VSn are input to the + input terminals of the comparators CPS1 to CPSn, respectively. One end of each column line LS1 to LSn is connected to the power supply Vcc via a resistor Rb (resistance value 100 kΩ). Each of the comparators CPS1 to CPSn compares the input voltage to the + input terminal and the input voltage to the − input terminal, and when the input voltage to the + input terminal is larger than the input voltage to the − input terminal, An H level signal is output.

  The row line driver 304 includes m three-state buffers BC1 to BCm and m comparators CPC1 to CPCm. The input terminals of the three-state buffers BC1 to BCm are grounded. The output terminals of the three-state buffers BC1 to BCm are connected to one ends of the row lines LC1 to LCm via resistors Rc (resistance values 1 to 5 kΩ), respectively.

  The + input terminals of the comparators CPC1 to CPCm are connected to one ends of the row lines LC1 to LCm, respectively. On the other hand, threshold voltages VC1 to VCm are input to the negative input terminals of the comparators CPC1 to CPCm, respectively. One end of each of the row lines LC1 to LCm is connected to the power source Vcc via a resistor Rd (resistance value 100 kΩ). Each of the comparators CPC1 to CPCm compares the input voltage to the + input terminal and the input voltage to the − input terminal, and when the input voltage to the + input terminal is larger than the input voltage to the − input terminal, An H level signal is output.

  Each of the three-state buffers BS1 to BSn of the column line driver 303 applies a voltage to one end of each of the column lines LS1 to LSn when a control signal from a control unit (not shown) becomes H level. Drive LSn. Here, the control signals to the three-state buffers BS1 to BSn are controlled so as to sequentially become H level. For example, when the control signal to the three-state buffer BSi connected to the i-th column line LSi from the left in FIG. 13 is at the H level, the control signal to the three-state buffer connected to the other column line is at the L level. It has become. That is, when the column line LSi is being driven, the three-state buffers connected to the other column lines are in a high impedance state. Thus, the column lines LS1 to LSn are sequentially driven by the three-state buffers BS1 to BSn.

  Each of the three-state buffers BC1 to BCm of the row line driver 304 applies a voltage to one end of each of the row lines LC1 to LCm, respectively, when a control signal from a control unit (not shown) becomes H level. To drive. Here, the control signals to the three-state buffers BC1 to BCm are controlled so as to sequentially become H level. For example, when the control signal to the three-state buffer BCi connected to the i-th row line LCi from the top in FIG. 13 is H level, the control signal to the three-state buffer connected to the other row line is L level. It has become. That is, when the row line LCi is driven, the three-state buffers connected to the other row lines are in a high impedance state. As a result, the row lines LC1 to LCm are sequentially driven by the three-state buffers BC1 to BCm.

  FIG. 14 is a diagram illustrating the touch position detection device 301 in a state where the point P301 is touched. When the point P301 is touched, the column line LSi and the row line LCi come into contact with each other. In this state, when each of the column lines LS1 to LSn is sequentially driven and the control signal to the three-state buffer BSi becomes H level, a current flows as indicated by an arrow, and from one end of the row line LCi to the + input terminal of the comparator CPCi. Voltage is output. Further, when the row lines LC1 to LCm are driven in a state where the point P301 is touched and the control signal to the three-state buffer BCi becomes H level, a current flows as shown by an arrow, and a comparator CPSi is connected from one end of the column line LSi. The voltage is output to the negative input terminal. As described above, when the column line LSi and the row line LCi are in contact with each other, when each of the column lines LS1 to LSn is sequentially driven, a voltage is output from one end of the row line LCi, and each of the row lines LC1 to LCm is driven. Then, a voltage is output from one end of the column line LSi.

  Here, in the touch position detection device 301, when the touch position is specified based only on whether or not the voltage is output, when a plurality of points are touched and so-called “wraparound” occurs, the touch position is accurately specified. There is a problem that you can not. The “wraparound” will be described with reference to FIG.

  FIG. 15 is a diagram illustrating the touch position detection device 301 in a state where the points P302 to P304 are touched. Also in this case, when each of the column lines LS1 to LSn is sequentially driven, a current flows as indicated by an arrow, and a voltage is output from one end of the row line LCi. Similarly, when each row line LC1 to LCm is driven, a voltage is output from one end of the column line LSi. That is, although the point P301 shown in FIG. 14 is not touched, the voltage is output from the same column line / row line that outputs a voltage when the point P301 is touched. . As described above, when “wraparound” occurs, the touch position cannot be accurately specified only by the presence / absence of voltage output.

  For this reason, in the touch position detecting device 301, the comparators CPC1 to CPCm compare the output voltages from the respective row lines LC1 to LCm with the threshold voltages VC1 to VCm, respectively, and the output signals of the comparators CPC1 to CPCm are The presence or absence of occurrence is detected. From FIG. 14 and FIG. 15, the current path when “wraparound” occurs is longer than the current path when “wraparound” does not occur, and therefore the current path when “wraparound” occurs. In this case, the resistance value is higher than that of the current path in the case where no “wraparound” occurs. For this reason, the output voltage from the row line LCi when “wraparound” occurs is lower than the output voltage from the row line LCi when “wraparound” does not occur.

  Therefore, in the touch position detection device 301, the threshold voltage VCi input to the negative input terminal of the comparator CPCi is greater than the voltage output from the row line LCi when the point P301 is touched and the column line LSi is driven. Set slightly lower. More specifically, the threshold voltage VCi is lower than the voltage output from the row line LCi via the current path when no “wraparound” occurs, and the current when “wraparound” occurs. The voltage is set higher than the voltage output from the row line LCi through the shortest current path among the paths. Further, since the internal resistance of the touch panel and the resistance values of the row line and the column line vary, the threshold voltage VCi is a voltage output from the row line LCi through a current path when no “wraparound” occurs. And an intermediate value between the voltage output from the row line LCi via the shortest current path among the current paths when the “wraparound” occurs. As a result, when the “wraparound” occurs, the output voltage from the row line LCi becomes lower than the threshold voltage VCi. Therefore, the output signal of the comparator CPCi becomes the L level, and only when the “wraparound” does not occur, the comparator The output signal of CPCi becomes H level.

  Similarly, in the touch position detection device 301, the comparators CPS1 to CPSn compare the output voltages from the respective column lines LS1 to LSn with the threshold voltages VS1 to VSn, respectively, and “wraparound” by the output signals of the comparators CPS1 to CPSn. The presence or absence of occurrence is detected. Since the current path when “wraparound” occurs is longer than the current path when “wraparound” does not occur, the output voltage from the column line LSi when “wraparound” occurs is The output voltage is higher than the output voltage from the column line LSi when no “wraparound” occurs. Therefore, the threshold voltage VSi input to the negative input terminal of the comparator CPSi is set slightly higher than the voltage output from the column line LSi when the point P301 is touched to drive the row line LCi. Specifically, the threshold voltage VSi is higher than the voltage output from the column line LSi via the current path when no “wraparound” occurs, and the current when “wraparound” occurs. The voltage is set lower than the voltage output from the column line LSi through the shortest current path among the paths. Furthermore, since the internal resistance of the touch panel and the resistance values of the row line and the column line vary, the threshold voltage VSi is a voltage output from the column line LSi via a current path when no “wraparound” occurs. And an intermediate value between the voltage output from the column line LSi via the shortest current path among the current paths when the “wraparound” occurs. Thereby, when the “wraparound” occurs, the output voltage from the column line LSi becomes lower than the threshold voltage VSi, so that the output signal of the comparator CPSi becomes L level, and only when the “wraparound” does not occur, The output signal of the comparator CPCi becomes H level.

  The touch position detection device 301 specifies a touch position by detecting a column line and a row line that are in contact with each other based on output signals from the comparators CPC1 to CPCm and the comparators CPS1 to CPSn. Here, the threshold voltages VC1 to VCm input to the negative input terminals of the comparators CPC1 to CPCm are set slightly lower than the output voltages from the row lines LC1 to LCm when no “wraparound” occurs, and the comparator CPS1 The threshold voltages VS1 to VSn input to the + input terminals of .about.CPSn are set slightly higher than the output voltages from the column lines LS1 to LSn when no “wraparound” occurs. This prevents an untouched position from being erroneously specified as a touch position by “wraparound”.

  A modification of the touch position detection device described in Patent Document 2 will be described with reference to FIGS.

  FIG. 16 is a diagram illustrating a configuration of the touch position detection device 401 described in Patent Document 2. As illustrated in FIG. The touch position detection device 401 includes a touch panel 402, a column line driver 403, and a row line driver 404. The configuration of the touch panel 402 is the same as that of the touch panel 302 illustrated in FIG.

  The column line driver 403 has a configuration in which the n comparators CPS1 to CPSn are replaced with n AD converters AS1 to ASn in the column line driver 303 shown in FIG. Input terminals of the AD converters AS1 to ASn are connected to one ends of the column lines LS1 to LSn, respectively. Each AD converter AS1 to ASn converts the output voltage from each column line LS1 to LSn into a digital signal and outputs it to a CPU (not shown).

  The row line driver 404 has a configuration in which m comparators CPC1 to CPCm are replaced with m AD converters AC1 to ACm in the row line driver 304 shown in FIG. Input terminals of the AD converters AC1 to ACm are connected to one ends of the row lines LC1 to LCm, respectively. Each AD converter AC1-ACm converts the output voltage from each row line LC1-LCm into a digital signal and outputs it to a CPU (not shown).

  Similarly to the three-state buffers BS1 to BSn of the column line driver 303 shown in FIG. 13, the three-state buffers BS1 to BSn of the column line driver 403 are connected to the column lines LS1 to LSn by a control signal from a control unit (not shown). Drive sequentially. Similarly to the three-state buffers BC1 to BCm of the row line driver 304 shown in FIG. 13, each of the three-state buffers BC1 to BCm of the row line driver 404 is controlled by a control signal from a control unit (not shown). Are driven sequentially.

  FIG. 17 is a diagram illustrating the touch position detection device 401 in a state where the point P401 is touched. When the point P401 is touched, the column line LSi and the row line LCi come into contact with each other. When the column line LSi is driven in this state, a current flows as shown by an arrow, and a voltage is output from one end of the row line LCi to the AD converter ACi. When the row line LCi is driven while the point P401 is touched, a current flows as indicated by an arrow, and a voltage is output from one end of the column line LSi to the AD converter ASi.

  Also in the touch position detection device 401, in order to avoid the problem of “wraparound”, the touch position is specified by comparing the digital values output from the AD converter ACi and the AD converter ASi with predetermined digital values. For example, as shown in FIG. 18, when “wraparound” is generated by touching points P402 to P404, the output voltage from the row line LCi is the row when “wraparound” has not occurred. The output voltage from the line LCi is lower, and the output voltage from the column line LSi is higher than the output voltage from the column line LSi when no “wraparound” occurs.

  Therefore, in the touch position detection device 401, a CPU (not shown) converts the digital value from the AD converter ACi to a digital value slightly lower than the digital value corresponding to the output voltage from the row line LCi when no “wraparound” occurs. Compared with the value, the digital value from the AD converter ASi is compared with a digital value slightly higher than the digital value corresponding to the output voltage from the column line LSi when no “wraparound” occurs. By specifying the touch position based on these comparisons, it is possible to prevent an untouched position from being erroneously specified as the touch position when “wraparound” occurs.

Japanese Patent Laid-Open No. 9-45184 (published February 14, 1997) European Patent Application Publication No. 1950649 (published July 30, 2008)

  However, the touch position detection device 301 shown in FIG. 13 and the touch position detection device 401 shown in FIG. 16 have the following problems.

  FIG. 19 is a diagram illustrating the touch position detection device 301 in a state where the points P301 and P305 are touched. When the point P305 is touched, when the column line LS1 is driven, a current flows as indicated by a broken line arrow. Here, since the current path indicated by the broken line arrow is shorter than the current path indicated by the solid line arrow, the output voltage from the row line LC1 is higher than the output voltage from the row line LCi. Therefore, the threshold voltage VC1 input to the negative input terminal of the comparator CPC1 needs to be set higher than the threshold voltage VCi input to the negative input terminal of the comparator CPCi. As described above, since the output voltages from the row lines LC1 to LCm differ depending on the current paths, the threshold voltages VC1 to VCm input to the negative input terminals of the comparators CPC1 to CPCm must be set different from each other.

  In addition, as shown in FIG. 20, when the point P301 and the point P306 on the same row line LCi are touched at different timings, the current path that flows to the comparator CPCi via the point P306 and the point P301 Therefore, the current paths flowing through the comparator CPCi have different lengths. Therefore, even in the same row line LCi, the output voltage differs depending on the driven column line. For this reason, every time the column line to be driven changes, the threshold voltages VC1 to VCm input to the negative input terminals of the comparators CPC1 to CPCm must be changed. Thus, the output voltage from the row line is different for each row line and for each column line to be driven. Similarly, the output voltage from the column line is different for each column line and for each row line to be driven. Therefore, the configuration for generating the threshold voltages VC1 to VCm becomes very complicated.

  Further, the touch position detection device 401 shown in FIG. 16 has a configuration in which an output voltage from the column line and the row line is converted into a digital value by an AD converter, and arithmetic processing is performed by the CPU. However, in general, an AD converter is a complicated and expensive circuit. Also in the touch position detection device 401, as in the touch position detection device 301 shown in FIG. 13, the output voltage from the row line differs for each row line and for each driven column line, and the output voltage from the column line. However, this is different for each column line and each row line to be driven. For this reason, the arithmetic processing in the CPU of the digital value output from each AD converter becomes complicated. In particular, when the number of column lines and row lines is increased to increase the definition, it is necessary to configure the CPU with a plurality of chips, which increases the cost.

  As described above, the conventional touch position detection devices 301 and 401 have a problem that the configuration is complicated in order to detect an accurate touch position while avoiding “wraparound”.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a touch position detection device that is low-cost and simple in configuration.

  In order to solve the above problems, a touch position detection device according to the present invention includes a plurality of column lines arranged in a row direction and a plurality of row lines arranged in the column direction apart from the column lines. Touch panel, a column line driving unit that sequentially drives each column line by applying a voltage to one end of each column line, and a row line that sequentially drives each row line by applying a voltage to one end of each row line When the driving unit and the column line driving unit are driving each column line, the voltage input from the one end of each row line is compared with a first threshold voltage, thereby pressing the touch panel. A row line detection unit for detecting a row line in contact with the column line, and a voltage input from the one end of each column line when the row line driving unit drives each row line A column position detection unit that detects a column line that is in contact with the row line by pressing the touch panel by comparing with a second threshold voltage, the touch position detection device comprising: When any one of the row lines touches one of the row lines, a voltage input to the row line detection unit from the one end of the row line that contacts the column line and a column that contacts the row line It is characterized by comprising input voltage steady means for making the voltage input from the one end of the line to the column line detection unit constant regardless of the combination of the column line and the row line in contact with each other.

  According to the above configuration, when the column line and the row line are in contact with each other by pressing on the touch panel, when the column line driving unit sequentially drives each column line, contact is made from the column line in contact with the row line. Via the position, a voltage is input to the row line detector via the row line in contact with the column line. In addition, when the column line and the row line are in contact with each other by pressing on the touch panel, when the row line driving unit sequentially drives each row line, from the row line in contact with the column line via the contact position, A voltage is input to the column line detector via the column line in contact with the row line. Therefore, more specifically, the first threshold voltage is set to be slightly different from the voltage input to the row line detection unit when no “wraparound” occurs. Are input to the row line detection unit via the shortest current path among the voltage input to the row line detection unit when “wraparound” does not occur and the current path when “wraparound” occurs. By setting the value between the line voltage and the output voltage, the row line detection unit detects the row line in contact with the column line only when “wraparound” has not occurred. Further, by setting the second threshold voltage to be slightly different from the voltage input to the column line detection unit when “wraparound” has not occurred, more specifically, the first threshold voltage is set. Are input to the column line detection unit via the shortest current path of the voltage input to the column line detection unit when “wraparound” does not occur and the current path when “wraparound” occurs. The column line detection unit detects the column line that is in contact with the row line only when no “wraparound” occurs. As a result, it is possible to avoid detection of an erroneous touch position when “wraparound” occurs.

  Further, when any one of the column lines and any one of the row lines are in contact with each other by the input voltage steady state means, a voltage input to the row line detection unit from one end of the row line that contacts the column line, And the voltage input into the column line detection part from the end of the column line which contacts a row line is respectively constant irrespective of the combination of the column line and row line which mutually contact. That is, when no “wraparound” occurs, the voltage input from the row line to the row line detection unit is constant regardless of the contact position, and the voltage input from the column line to the column line detection unit is Constant regardless of position.

  Therefore, unlike the conventional touch position detection device, it is not necessary to change the first threshold voltage for each row line or change the second threshold voltage for each column line. Therefore, the configuration of the voltage source that generates the first threshold voltage and the second threshold voltage can be simplified. Therefore, there is an effect that it is possible to realize a touch position detecting device with a simple configuration at low cost.

  In the touch position detecting device according to the present invention, the input voltage steady-state means may be configured such that when any one of the column lines is in contact with any one of the row lines, the column line driving unit and the contact position are Between the resistance value between the row line detection unit and the contact position, and the resistance value between the row line drive unit and the contact position, and between the column line detection unit and the contact position. The resistance value steady-state means for making the sum of the resistance value of each of the column lines and the row lines constant with each other regardless of the combination of the column line and the row line, wherein the resistance value steady-state means has the same number of column line resistors as the column lines. And one end of each column line resistor is connected to the column line driver and the column line detector, and the other end of each column line resistor is connected to each column. Connected to the one end of the line and one of the row line resistors Is connected to the row line drive unit and the row line detection unit, and the other end of each row line resistor is connected to the one end of each row line, and the column line drive unit drives each column line The voltages applied to one end of each column line resistor are equal to each other, and the voltages applied to one end of each row line resistor when the row line driver is driving each row line are equal to each other. The resistance is smaller as the order of arrangement from the one end side of the row line of the column line to be connected is smaller, and each row line resistance is from the one end side of the column line of the connected row line. The larger the order of arrangement, the smaller the resistance value.

  When the column line and the row line are in contact, the resistance value from one end of the column line in contact with the row line to one end of the row line in contact with the column line via the contact position varies depending on the contact position. Therefore, in the above configuration, the column line resistance is connected to one end of each column line, the row line resistance is connected to one end of each row line, and each column line resistance is connected from one end side of the row line of the connected column line. The resistance value decreases as the order of arrangement increases, and the resistance value of each row line resistor decreases as the arrangement order from one end side of the column line of the connected row line increases. Thus, when any one of the column lines and any one of the row lines are in contact, the resistance value between the column line driving unit and the contact position, and between the row line detection unit and the contact position The sum of the resistance value is constant regardless of the contact position, and the sum of the resistance value between the row line driving unit and the contact position and the resistance value between the column line detection unit and the contact position is It is constant regardless of the contact position. Further, when the column line driver is driving each column line, voltages applied to one end of each column line resistor are equal to each other, and each row line resistor is driven when the row line driver is driving each row line. The voltages applied to one end of each are equal to each other. Therefore, the voltage input to the row line detection unit from one end of the row line contacting the column line is constant regardless of the contact position, and the voltage input to the column line detection unit from one end of the column line contacting the row line. However, it is constant regardless of the contact position. Therefore, there is no need to change the first threshold voltage for each row line or change the second threshold voltage for each column line.

  In the touch position detection device according to the present invention, the input voltage steady means may set the column line that sets the voltage applied by the column line driver higher to the column line in which the order of arrangement from the one end side of the row line is larger. The applied voltage setting means, and the row line applied voltage setting means for setting the voltage applied by the row line driver higher for the row line in which the order of arrangement from the one end side of the column line is larger. Is preferred.

  When the column line and the row line are in contact with each other, the farther the contact position is from the one end side of the row line and the farther from the one end side of the column line, the farther the row line passes through the contact position from the one end of the column line. The resistance value to one end of becomes higher. Therefore, in the above configuration, the column line in which the order of arrangement from the one end side of the row line is large, that is, the column line far from the one end side of the row line has a higher voltage applied by the column line driving unit. The voltage applied by the row line driving unit is higher in a row line in which the order of arrangement from one end side of the row is larger, that is, in a row line far from one end side of the column line. Therefore, the voltage input to the row line detection unit from one end of the row line contacting the column line is constant regardless of the contact position, and the voltage input to the column line detection unit from one end of the column line contacting the row line. However, it is constant regardless of the contact position. Therefore, there is no need to change the first threshold voltage for each row line or change the second threshold voltage for each column line.

  In the touch position detecting device according to the present invention, the column line driving unit, the row line driving unit, the row line detecting unit, and the column line detecting unit are provided one by one, and the row line driving unit and A first selector that alternatively connects the row line detector to one end of each row line resistor, and the column line driver and the column line detector alternatively to one end of each column line resistor. It is preferable to include a second selector that is sequentially connected.

  In the touch position detecting device according to the present invention, the column line driving unit, the row line driving unit, the row line detecting unit, and the column line detecting unit are provided one by one, and the row line driving unit and A first selector that selectively connects the row line detection unit to one end of each row line, and the column line driving unit and the column line detection unit are alternatively connected sequentially to one end of each column line. And a second selector.

  According to said structure, a 1st selector can make a row line drive part and a row line detection part common, without providing for every row line. In addition, the second selector can share the column line driving unit and the column line detection unit without providing each column line. Therefore, the configuration of the touch position detection device can be further simplified.

  As described above, the touch position detection device according to the present invention includes a plurality of column lines arranged in a row direction and a touch panel having a plurality of row lines arranged in the column direction apart from the column lines, A column line driver that sequentially drives each column line by applying a voltage to one end of each column line; and a row line driver that sequentially drives each row line by applying a voltage to one end of each row line; When the column line driver is driving each column line, the voltage input from the one end of each row line is compared with a first threshold voltage, thereby making contact with the column line by pressing the touch panel A row line detection unit that detects a row line that is being operated, and a voltage input from the one end of each column line when the row line driving unit drives each row line. And a column line detection unit that detects a column line that is in contact with the row line by pressing the touch panel, and the touch position detection device includes any one of the column lines, When any one of the row lines is in contact, the voltage input to the row line detection unit from the one end of the row line in contact with the column line, and the one end of the column line in contact with the row line Since the input voltage steady state means for making the voltage input to the column line detection unit constant regardless of the combination of the column line and the row line that are in contact with each other, the touch is simple and low in cost. The position detecting device can be realized.

It is a figure which shows the structure of the touch position detection apparatus which concerns on embodiment of this invention. In the said touch position detection apparatus, it is a figure which shows the state in which 3 places were touched. It is a figure which shows the state which "wraparound" generate | occur | produced in the said touch position detection apparatus. It is a circuit diagram which shows an example of the structure for inputting a common threshold voltage into the-input terminal of each comparator of the row line driver of the said touch position detection apparatus. It is a figure which shows the structure of the touch position detection apparatus which concerns on the modification of embodiment of this invention. FIG. 6 is a diagram illustrating a state where three places are touched in the touch position detection device illustrated in FIG. 5. It is a figure which shows the structure of the row line driver which concerns on the modification of this embodiment. It is a figure which shows the structure of the column line driver which concerns on the modification of this embodiment. It is a figure which shows the structure of the row line driver which concerns on the other modification of this embodiment. It is a figure which shows the structure of the column line driver which concerns on the other modification of this embodiment. (A) And (b) is a perspective view which shows schematic structure of the touch position detection apparatus using the analog type touch panel, (c) is a circuit diagram which shows schematic structure of the said touch position detection apparatus. 10 is a plan view showing a configuration of a touch position detection device described in Patent Literature 1. FIG. It is a figure which shows the structure of the touch position detection apparatus of patent document 2. FIG. It is a figure which shows the state in which one place was touched in the touch position detection apparatus shown in FIG. FIG. 14 is a diagram showing a state where “wraparound” has occurred in the touch position detection device shown in FIG. 13. It is a figure which shows the structure of the other touch position detection apparatus described in patent document 2. FIG. FIG. 17 is a diagram illustrating a state in which one place is touched in the touch position detection device illustrated in FIG. 16. FIG. 17 is a diagram illustrating a state where “wraparound” has occurred in the touch position detection device illustrated in FIG. 16. It is a figure which shows the state in which two places were touched in the touch position detection apparatus shown in FIG. FIG. 14 is a diagram illustrating a state in which two places on the same row line are touched in the touch position detection device illustrated in FIG. 13.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating a configuration of a touch position detection apparatus 1 according to the present embodiment. The touch position detection device 1 includes a touch panel 2, a column line driver 3, a row line driver 4, n column line resistors RS1 to RSn, and m row line resistors RC1 to RCm. The touch panel 2 has the same configuration as the touch panel 302 shown in FIG. 13, and has n column lines LS1 to LSn arranged in the row direction and m pieces arranged in the column direction apart from the column lines LS1 to LSn. Row lines LC1 to LCm. In FIG. 1, 14 column lines and 16 row lines are shown, but the number of column lines and row lines is appropriately set according to the size of touch panel 2 and the position detection accuracy. In FIG. 1, the same members as those shown in FIG. 13 are denoted by the same reference numerals for convenience.

  The column line resistors RS <b> 1 to RSn are provided between the touch panel 2 and the column line driver 3. Further, the row line resistors RC <b> 1 to RCm are provided between the touch panel 2 and the row line driver 4. The resistance values of the column line resistors RS1 to RSn and the resistance values of the row line resistors RC1 to RCm will be described later.

  The column line driver 3 includes n three-state buffers BS1 to BSn and n comparators CPS1 to CPSn. The input terminals of the three-state buffers BS1 to BSn are connected to the power supply Vcc. The output terminals of the three-state buffers BS1 to BSn are connected to one ends of the column line resistors RS1 to RSn via resistors Ra (resistance values 1 to 5 kΩ), respectively. The other ends of the column line resistors RS1 to RSn are connected to one ends of the column lines LS1 to LSn, respectively.

  Each of the three-state buffers BS1 to BSn of the column line driver 3 is a member corresponding to the column line driving unit described in the claims. When a control signal from a control unit (not shown) becomes H level, Each column line LS1 to LSn is driven by applying a voltage to one end of LS1 to LSn. Here, the control signals to the three-state buffers BS1 to BSn are controlled so as to sequentially become H level. For example, when the control signal to the three-state buffer BSi connected to the i-th column line LSi from the left in FIG. 1 is H level, the control signal to the three-state buffer connected to the other column line is L level. It has become. That is, when the column line LSi is being driven, the three-state buffers connected to the other column lines are in a high impedance state. Thus, the column lines LS1 to LSn are sequentially driven by the three-state buffers BS1 to BSn.

  Each of the comparators CPS1 to CPSn of the column line driver 3 is a member corresponding to the column line detection unit described in the claims. The negative input terminal of each comparator CPS1 to CPSn is connected to one end of each column line resistor RS1 to RSn. On the other hand, the threshold voltage VS (second threshold voltage) is input to the + input terminals of the comparators CPS1 to CPSn. One end of each column line resistor RS1 to RSn is connected to the power supply Vcc via a resistor Rb (resistance value 100 kΩ). Each of the comparators CPS1 to CPSn compares the input voltage to the + input terminal and the input voltage to the − input terminal, and when the input voltage to the + input terminal is larger than the input voltage to the − input terminal, An H level signal is output.

  The row line driver 4 includes m three-state buffers BC1 to BCm and m comparators CPC1 to CPCm. The input terminals of the three-state buffers BC1 to BCm are grounded. The output terminals of the three-state buffers BC1 to BCm are connected to one ends of the row line resistors RC1 to RCm via resistors Rc (resistance values 1 to 5 kΩ), respectively. The other ends of the row line resistors RC1 to RCm are connected to one ends of the row lines LC1 to LCm, respectively.

  Each of the three-state buffers BC1 to BCm of the row line driver 4 is a member corresponding to the row line driving unit described in the claims. When a control signal from a control unit (not shown) becomes H level, each row line LC1 Each of the row lines LC1 to LCm is driven by applying a voltage to one end of the LCm. Here, the control signals to the three-state buffers BC1 to BCm are controlled so as to sequentially become H level. For example, when the control signal to the three-state buffer BCi connected to the i-th row line LCi from the top in FIG. 1 is at the H level, the control signal to the three-state buffer connected to the other row line is at the L level. It has become. That is, when the row line LCi is driven, the three-state buffers connected to the other row lines are in a high impedance state. As a result, the row lines LC1 to LCm are sequentially driven by the three-state buffers BC1 to BCm.

  Each of the comparators CPC1 to CPCm of the row line driver 4 is a member corresponding to the row line detection unit described in the claims. The + input terminals of the comparators CPC1 to CPCm are connected to one ends of the row line resistors RC1 to RCm, respectively. On the other hand, the threshold voltage VC (first threshold voltage) is input to the negative input terminals of the comparators CPC1 to CPCm. One end of each of the row line resistors RC1 to RCm is connected to the power supply Vcc via a resistor Rd (resistance value 100 kΩ). Each of the comparators CPC1 to CPCm compares the input voltage to the + input terminal and the input voltage to the − input terminal, and when the input voltage to the + input terminal is larger than the input voltage to the − input terminal, An H level signal is output.

  Output signals from the comparators CPS1 to CPSn of the column line driver 3 and the comparators CPC1 to CPCm of the row line driver 4 are input to a CPU (not shown). When the CPU outputs an H level signal from any one of the comparators CPS1 to CPSn, the row line in which a voltage is input to the negative input terminal of the comparator that outputs the H level signal is set to any column line. It is determined that the contact has been made. In addition, when an H level signal is output from any of the comparators CPC1 to CPCm, the CPU selects any column line in which a voltage is input to the + input terminal of the comparator that has output the H level signal. It is determined that the line is touched. Thereby, the column line and row line which are mutually contacting by the press to the touch panel 2 are specified, and the touch position detection apparatus 1 can detect a touch position. Note that flip-flops may be provided between the output terminals of the comparators CPC1 to CPCm and CPS1 to CPSn and the CPU.

  The touch position detection device 1 according to the present embodiment further includes column line resistances RS1 to RSn and row line resistances RC1 to RCn as compared with the conventional touch position detection device 301 shown in FIG. The threshold voltages VS and VC are differently input to the + input terminals of the comparators CPS1 to CPSn and the-input terminals of the comparators CPC1 to CPCm, respectively. In the touch position detection device 1, column line resistors RS1 to RSn and row line resistors RC1 to RCn are provided, so that any one of the column lines LS1 to LSn (for example, the column line LSi) and the row line are provided. When one of LC1 to LCm (for example, the row line LCi) contacts, the voltage input to the comparator CPCi from one end of the row line LCi that contacts the column line LSi and the row line LCi The voltage input to the comparator CPSi from one end of the column line LSi to be fixed is constant regardless of the combination of the column line and the row line that are in contact with each other. First, resistance values of the column line resistors RS1 to RSn and resistance values of the row line resistors RC1 to RCm will be described.

  The column line resistors RS1 to RSn have a resistance value that increases as the order of arrangement from one end side (row line driver 4 side) of the row line of the connected column line increases (that is, the farther from one end side of the row line). small. That is, the resistance value of the column line resistor RS1> the resistance value of the column line resistor RS2>...> The resistance value of the column line resistor RSn. More specifically, assuming that the length of one side in the horizontal direction of each matrix formed by the column lines LS1 to LSn and the row lines LC1 to LCm is Δx, the difference between the resistance values of adjacent column line resistances is It is set to be equal to the resistance value per line length Δx.

  In other words, the resistance value of the column line resistance RSi is the resistance value of the row line (for example, the column line resistance) at the distance between the column line LSi to which the column line resistance RSi is connected and the rightmost column line LSn in FIG. Resistance value between the intersection of LSi and row line LC1 and the intersection of column line LSn and row line LC1). For example, when the number of the column lines LS1 to LSn is 100 and the resistance value per row line length Δx is 100Ω, the resistance value of the column line resistor RS1 = 9900Ω and the resistance value of the column line resistor RS2 = 9800Ω. , The resistance value of the column line resistor RS3 = 9700Ω,..., The resistance value of the column line resistor RS100 = 0Ω.

  In addition, the row line resistances RC1 to RCm increase in resistance as the order of arrangement from one end side (column line driver 3 side) of the column line of the connected row line increases (that is, the farther from the one end side of the column line). The value is small. That is, the resistance value of the row line resistor RC1> the resistance value of the row line resistor RC2>...> The resistance value of the row line resistor RCm. More specifically, if the length of one side in the vertical direction of each matrix formed by the column lines LS1 to LSn and the row lines LC1 to LCm is Δy, the difference between the resistance values of the adjacent row line resistors is It is set to be equal to the resistance value per line length Δy.

  In other words, the resistance value of the row line resistor RCi is the resistance value of the column line (for example, the row line resistor) at the distance between the row line LCi to which the row line resistor RCi is connected and the lower row line LCm in FIG. Resistance value between the intersection of LCi and column line LS1 and the intersection of row line LCm and column line LS1). For example, when the number of row lines LC1 to LCm is 100 and the resistance value per row line length Δy is 100Ω, the resistance value of the row line resistor RC1 = 9900Ω and the resistance value of the row line resistor RC2 = 9800Ω. , The resistance value of the row line resistor RC3 = 9700Ω,..., The resistance value of the row line resistor RC100 = 0Ω.

  By setting the resistance values of the column line resistors RS1 to RSn and the row line resistors RC1 to RCm as described above, the column line resistors RS1 to RSn and the row line resistors RC1 to RCm are described in the claims. The resistance value steady state means is configured. That is, when any one of the column lines LS1 to LSn is in contact with any one of the row lines LC1 to LCm, the resistance value between the three-state buffer that drives the contacting column line and the contact position The sum of the output voltage from the contacting row line and the resistance value between the comparator and the contact position input to the + input terminal is constant regardless of the combination of the column line and the row line that are in contact with each other. In addition, when any one of the column lines LS1 to LSn is in contact with any one of the row lines LC1 to LCm, a resistance value between the three-state buffer that drives the contacting row line and the contact position The sum of the output voltage from the contacting column line and the resistance value between the comparator and the contact position input to the negative input terminal is constant regardless of the combination of the column line and the row line that are in contact with each other.

  In other words, when any one of the column lines LS1 to LSn is in contact with any one of the row lines LC1 to LCm and the contacting column line or row line is driven, the column line driver 3 and the row line The resistance value of the path of the current flowing between the driver 4 via the contact position is constant regardless of the contact position.

  FIG. 2 is a diagram illustrating the touch position detection device 1 in a state where the points P1 to P3 are touched. When the point P1 is touched, the column line LSi and the row line LCi come into contact with each other. In this state, when each of the column lines LS1 to LSn is sequentially driven and the control signal to the three-state buffer BSi becomes H level, a current flows as indicated by a solid line arrow, and the + input terminal of the comparator CPCi starts from one end of the row line LCi. Voltage is output to When the row line LC1 to LCm is driven with the point P1 being touched and the control signal to the three-state buffer BCi becomes H level, a current flows as shown by an arrow, and the comparator CPSi is connected from one end of the column line LSi. The voltage is output to the negative input terminal. As described above, when the column line LSi and the row line LCi are in contact with each other, when each of the column lines LS1 to LSn is sequentially driven, a voltage is output from one end of the row line LCi, and each of the row lines LC1 to LCm is driven. Then, a voltage is output from one end of the column line LSi.

  Similarly, when the point P2 is touched, the column line LS1 and the row line LC1 come into contact with each other, and when each of the column lines LS1 to LSn is sequentially driven, a current flows as indicated by a one-dot chain line arrow. Further, when the point P3 is touched, the column line LSn and the row line LCm come into contact with each other, and when each of the column lines LS1 to LSn is sequentially driven, a current flows as indicated by broken line arrows. Here, a current path indicated by a solid arrow (hereinafter “current path 1”), a current path indicated by a one-dot chain arrow (hereinafter “current path 2”), and a current path indicated by a dashed arrow (hereinafter “current path”). 3)), the resistance value in the touch panel 2 becomes current path 2 <current path 1 <current path 3 because the current path 2, current path 1, and current path 3 become longer in this order.

  On the other hand, the resistance values of the column line resistors RS1 to RSn are set so that the resistance value of the column line resistor RS1> the resistance value of the column line resistor RS2>...> The resistance value of the column line resistor RSn. The resistance values of the row line resistors RC1 to RCm are set such that the resistance value of the row line resistor RC1> the resistance value of the row line resistor RC2>...> The resistance value of the row line resistor RCm. As a result, the resistance value of the path of the current flowing between the column line driver 3 and the row line driver 4 via the contact position between the column line and the row line is constant regardless of the contact position. For example, in FIG. 2, the current path 1, the current path 2, and the current path 3 have the same resistance value in the entire path.

  Also, since the input terminals of the three-state buffers BS1 to BSn are all connected to the power supply Vcc, each column line resistance when the three-state buffers BS1 to BSn drive the column lines LS1 to LSn. The voltages applied to RS1 to RSn are equal to each other. Therefore, when no “wraparound” occurs, the voltages input from the row line resistors RC1 to RCm to the + input terminals of the comparators CPC1 to CPCm are equal to each other. For example, in FIG. 2, the voltage V1 input to the + input terminal of the comparator CPC1, the voltage Vi input to the + input terminal of the comparator CPCi, and the voltage Vm input to the + input terminal of the comparator CPCm are mutually Will be equal. Thereby, the threshold voltages VC input to the negative input terminals of the comparators CPC1 to CPCm can be set equal to each other.

  As shown in FIG. 3, when a “wraparound” occurs by touching points P4 to P6, when the column line LSi is driven, an input is made from the row line LCi to the + input terminal of the comparator CPCi. The applied voltage is lower than the voltage Vi shown in FIG. For this reason, in the touch position detection device 1, the threshold voltage VC input to the negative input terminals of the comparators CPC1 to CPCm is changed from the row line resistors RC1 to RCm to the comparators CPC1 to CPCm when the “wraparound” has not occurred. Is set slightly lower than the voltage (V1 = Vi = Vm) input to the + input terminal. As a result, when a “wraparound” occurs, even if a voltage is input to any of the positive input terminals of the comparators CPC1 to CPCm, an H level signal is not output from the comparator. This prevents an untouched position from being erroneously specified as a touch position by “wraparound”.

  Next, the case where the row lines LC1 to LCm are driven will be described with reference to FIG. 2 again. As described above, when any one of the column lines LS1 to LSn is in contact with any one of the row lines LC1 to LCm and the contacting column line or row line is driven, the column line driver 3 The resistance value of the path of the current flowing between the row line driver 4 via the contact position is constant regardless of the contact position. Since the input terminals of the three-state buffers BC1 to BCm are all grounded, the three-state buffers BC1 to BCm are applied to the row line resistors RC1 to RCm when the three-state buffers BC1 to BCm are driving the row lines LC1 to LCm. The applied voltages are equal to each other. For this reason, when the row lines LC1 to LCm are driven, voltages input from the column line resistors RS1 to RSn to the negative input terminals of the comparators CPS1 to CPSn are equal to each other. Thereby, the threshold voltages VS input to the + input terminals of the comparators CPS1 to CPSn can be set to be equal to each other.

  FIG. 4 is a circuit diagram showing an example of a configuration for inputting a common threshold voltage VC to the negative input terminals of the comparators CPC1 to CPCm of the row line driver 4. A voltage dividing resistor Re and a voltage dividing resistor Rf are connected in series between the power source Vcc and the ground. The negative input terminals of the comparators CPC1 to CPCm are connected to the voltage dividing resistor Re and the voltage dividing resistor Rf. It is connected to the. The threshold voltage VC input to the negative input terminals of the comparators CPC1 to CPCm is set by the resistance values of the voltage dividing resistor Re and the voltage dividing resistor Rf. A Zener diode may be used instead of the voltage dividing resistor Re and the voltage dividing resistor Rf.

  As described above, in the touch position detection device 1 according to the present embodiment, the threshold voltages VC input to the negative input terminals of the comparators CPC1 to CPCm are equal to each other, so that the voltage sources that generate the threshold voltage VC are shared. Can do. In addition, regarding the configuration for inputting the common threshold voltage VS to the + input terminals of the comparators CPS1 to CPSn of the column line driver 3, the threshold voltages VS input to the + input terminals of the comparators CPS1 to CPSn are equal to each other. Therefore, a voltage source for generating the threshold voltage VS can be shared. Therefore, the configuration of the touch position detection device 1 can be greatly simplified as compared with the conventional touch position detection device.

  Subsequently, modified examples of the present embodiment will be described with reference to FIGS.

  FIG. 5 is a diagram illustrating a configuration of the touch position detection device 11 according to a modification of the present embodiment. In the figure, only members having different functions from those in the touch position detecting device 1 shown in FIG. 1 are given different reference numerals, and members having the same functions as those in the touch position detecting device 1 are given the same reference numerals. The description is omitted.

  The touch position detection device 11 includes a touch panel 2, a column line driver 13, and a row line driver 14. That is, the touch position detection device 11 does not include the column line resistors RS1 to RSn and the row line resistors RC1 to RCm as compared with the touch position detection device 1 shown in FIG. The driver 4 is replaced with a column line driver 13 and a row line driver 14, respectively.

  The column line driver 13 includes n DA converters DS1 to DSn and n comparators CPS1 to CPSn. A digital signal is input to the input terminals of the DA converters DS1 to DSn from a CPU (not shown). The output terminals of the DA converters DS1 to DSn are connected to one end of each column line LS1 to LSn via a resistor Ra (resistance value 1 to 5 kΩ).

  The comparators CPS1 to CPSn of the column line driver 13 have the same configuration as the comparators CPS1 to CPSn of the column line driver 3 shown in FIG. That is, the negative input terminals of the comparators CPS1 to CPSn are connected to one ends of the column lines LS1 to LSn, respectively. On the other hand, a common threshold voltage VS (second threshold voltage) is input to the + input terminals of the comparators CPS1 to CPSn.

  Thus, the column line driver 13 has a configuration in which the three-state buffers BS1 to BSn are replaced with the DA converters DS1 to DSn in the column line driver 3 shown in FIG.

  Each DA converter DS1 to DSn of the column line driver 13 is a member corresponding to the column line driving unit described in the claims, and when a digital signal is input from the CPU, one end of each column line LS1 to LSn, respectively. Each column line LS1 to LSn is driven by applying a voltage according to a digital signal to the column line LS1. The DA converters DS1 to DSn are in a high impedance state when no digital signal is input from the CPU. Here, the CPU outputs digital signals to the DA converters DS1 to DSn so that the column lines LS1 to LSn are sequentially driven.

  The row line driver 14 includes m DA converters DC1 to DCm and m comparators CPC1 to CPCm. A digital signal is input to an input terminal of each DA converter DC1 to DCm from a CPU (not shown). The output terminals of the DA converters DC1 to DCm are respectively connected to one ends of the row lines LC1 to LCm via resistors Rc (resistance values 1 to 5 kΩ).

  The comparators CPC1 to CPCm of the row line driver 14 have the same configuration as the comparators CPC1 to CPCm of the row line driver 4 shown in FIG. That is, the + input terminals of the comparators CPC1 to CPCm are connected to one ends of the row lines LC1 to LCm, respectively. On the other hand, a common threshold voltage VC (first threshold voltage) is input to the negative input terminals of the comparators CPC1 to CPCm.

  As described above, the row line driver 14 is configured by replacing the three-state buffers BC1 to BCm with the DA converters DC1 to DCm in the row line driver 4 shown in FIG.

  Each DA converter DC1 to DCm of the row line driver 14 is a member corresponding to the row line driving unit described in the claims. When a digital signal is input from the CPU, each DA converter DC1 to DCm is connected to one end of each row line LC1 to LCm. The row lines LC1 to LCm are driven by applying a voltage corresponding to the digital signal. The DA converters DC1 to DCm are in a high impedance state when no digital signal is input from the CPU. Here, the CPU outputs digital signals to the DA converters DC1 to DCm so that the row lines LC1 to LCm are sequentially driven.

  As with the touch position detection device 1 shown in FIG. 1, the touch position detection device 11 shown in FIG. 5 is one of the column lines LS1 to LSn (for example, the column line LSi) and one of the row lines LC1 to LCm. When one line (for example, the row line LCi) contacts, the voltage input to the comparator CPCi from one end of the row line LCi that contacts the column line LSi, and one end of the column line LSi that contacts the row line LCi The voltage input to the comparator CPSi is constant regardless of the combination of the column line and the row line that are in contact with each other. For example, as shown in FIG. 6, when the points P1 to P3 are touched, the voltage Vi input from the current path 1 indicated by the solid line arrow to the + input terminal of the comparator CPCi and the current path indicated by the one-dot chain line arrow The voltage V1 input to the + input terminal of the comparator CPC1 from 2 is equal to the voltage Vm input to the + input terminal of the comparator CPCm from the current path 3 indicated by the dashed arrow.

  In order to realize this configuration, in the touch position detection device 11, a column line having a larger arrangement order from one end side (row line driver 14 side) of the row lines LC1 to LCm (that is, one end of the row lines LC1 to LCm). The higher the voltage applied by each DA converter DS1 to DSn, the higher the order of the arrangement from one end side (column line driver 13 side) of the column lines LS1 to LSn (that is, the column line farther from the side) The row lines farther from one end side of the column lines LS1 to LSn) are set so that the voltages applied by the DA converters DC1 to DCm are higher. Specifically, the output voltages of the DA converters DS1 to DSn are: the output voltage of the DA converter DS1 <the output voltage of the DA converter DS2 <... <the output voltage of the DA converter DSn. Further, the output voltages of the DA converters DC1 to DCm are the output voltage of the DA converter DC1 <the output voltage of the DA converter DC2 <... <The output voltage of the DA converter DCm.

  The output voltages of the DA converters DC1 to DCm and the DA converters DS1 to DSn are set by digital signals from the CPU. That is, the CPU has a function of setting the value of a digital signal input to each DA converter DC1 to DCm and a function of setting the value of a digital signal input to each DA converter DS1 to DSn. The function of setting the value of the digital signal input to each DA converter DC1 to DCm corresponds to the row line applied voltage setting means described in the claims, and the function of the digital signal input to each DA converter DS1 to DSn. The function of setting a value corresponds to the column line applied voltage setting means described in the claims.

  Thereby, also in the touch position detection device 11, the threshold voltages VC input to the negative input terminals of the comparators CPC1 to CPCm can be set to be equal to each other as in the touch position detection device 1 shown in FIG. The threshold voltages VS input to the positive input terminals of CPS1 to CPSn can be set equal to each other. Further, the DA converter has a simple circuit configuration and a low cost compared to the AD converter of the conventional touch position detection apparatus 401 shown in FIG. Therefore, the configuration of the touch position detection device 11 can be greatly simplified as compared with the conventional touch position detection device.

  In the above description, the two configurations have been described roughly so that the voltage input to the + input terminals of the comparators CPC1 to CPCm and the voltage input to the − input terminals of the comparators CPS1 to CPSn are constant. That is, like the touch position detection device 1 shown in FIG. 1, the column line resistors RS1 to RSn and the row line resistors RC1 to RCm are provided, and the current passes through the touch position between the column line driver 3 and the row line driver 4. The configuration in which the resistance value of the path is made constant regardless of the touch position, and the voltage applied to the column lines LS1 to LSn and the row lines LC1 to LCm as in the touch position detection device 11 shown in FIG. The configuration for sequentially changing the applied voltage has been described.

  However, this embodiment is configured so that the voltage input to the + input terminals of the comparators CPC1 to CPCm and the voltage input to the − input terminals of the comparators CPS1 to CPSn are constant, that is, the claims If it is a structure provided with the input voltage steady means as described in the range, it will not be limited to said 2 structure. For example, in the touch position detection device 1 shown in FIG. 1, a DA converter is provided instead of the three-state buffers BS1 to BSn / BC1 to BCm, the output voltage of each DA converter, the resistance values of the column line resistors RS1 to RSn, and the row line The resistance values of the resistors RC1 to RCm are appropriately set so that the voltages input to the + input terminals of the comparators CPC1 to CPCm and the voltages input to the − input terminals of the comparators CPS1 to CPSn are respectively constant. Also good.

  In the above, the three-state buffers BS1 to BSn, DA converters DS1 to DSn, and comparators CPS1 to CPSn are provided in the same number as the column lines LS1 to LSn, respectively, and the three-state buffers BC1 to BCm, DA converters DC1 to DCm, and the comparator CPC1 The configuration in which the same number of .about.CPCm as the row lines LC1 to LCm are provided has been described. Next, a configuration in which one three-state buffer for driving the row lines LC1 to LCm and one comparator to which voltages from the row lines LC1 to LCm are input will be described with reference to FIG.

  FIG. 7 is a diagram illustrating a configuration of the row line driver 24 according to a modification of the present embodiment. The row line driver 24 includes one three-state buffer BC and one comparator CPC, and further includes an analog selector S1. The three-state buffer BC and the comparator CPC have the same configuration as the three-state buffers BC1 to BCm and the comparators CPC1 to CPCm shown in FIG.

  The analog selector S1 is a member corresponding to the first selector described in the claims, and has m input terminals and one output terminal. Each input terminal of the analog selector S1 is connected to one end of each of the row line resistors RC1 to RCm. A connection point between each input terminal of the analog selector S1 and one end of each row line resistor RC1 to RCm is connected to the power supply Vcc via the resistor Rd. Further, the + input terminal of the comparator CPC is connected to the output terminal of the analog selector S1, and the output terminal of the three-state buffer BC is connected to the output terminal of the analog selector S1 via the resistor Rc.

  The analog selector S1 alternatively connects the three-state buffer BC and the comparator CPC sequentially with one end of each of the row line resistors RC1 to RCm based on a select signal SEL1 from a CPU (not shown). As a result, the three-state buffer BC can sequentially drive the row lines LC1 to LCm. Further, output voltages from the respective row lines LC1 to LCm are sequentially input to the + input terminal of the comparator CPC.

  As described above, the row line driver 24 includes the analog selector S1 so that the three-state buffer BC and the comparator CPC can be shared. Therefore, the configuration of the row line driver 24 can be further simplified as compared with the row line driver 4 shown in FIG.

  Next, a configuration in which one three-state buffer for driving the column lines LS1 to LSn and one comparator to which voltages from the column lines LS1 to LSn are input will be described with reference to FIG.

  FIG. 8 is a diagram showing a configuration of the column line driver 23 according to a modification of the present embodiment. The column line driver 23 includes one three-state buffer BS and one comparator CPS, and further includes an analog selector S2. Three-state buffer BS and comparator CPS have the same configuration as three-state buffers BS1 to BSn and comparators CPS1 to CPSn shown in FIG. 1, respectively.

  The analog selector S2 is a member corresponding to the second selector described in the claims, and has n input terminals and one output terminal. Each input terminal of the analog selector S2 is connected to one end of each of the column line resistors RS1 to RSn. A connection point between each input terminal of the analog selector S2 and one end of each column line resistor RS1 to RSn is connected to the power source Vcc via a resistor Rb. The negative input terminal of the comparator CPS is connected to the output terminal of the analog selector S2, and the output terminal of the three-state buffer BS is connected to the output terminal of the analog selector S2 via the resistor Ra.

  The analog selector S2 alternatively and sequentially connects the three-state buffer BS and the comparator CPS to one end of each column line resistor RS1 to RSn based on a select signal SEL2 from a CPU (not shown). As a result, the three-state buffer BS can sequentially drive the column lines LS1 to LSn. In addition, output voltages from the column lines LS1 to LSn are sequentially input to the negative input terminal of the comparator CPS.

  As described above, the column line driver 23 includes the analog selector S2, so that the three-state buffer BS and the comparator CPS can be shared. Therefore, the configuration of the column line driver 23 can be further simplified as compared with the column line driver 3 shown in FIG.

  Next, a configuration in which one DA converter that drives the row lines LC1 to LCm and one comparator to which voltages from the row lines LC1 to LCm are input will be described with reference to FIG.

  FIG. 9 is a diagram illustrating a configuration of a row line driver 34 according to another modification of the present embodiment. The row line driver 34 includes one DA converter DC and one comparator CPC, and further includes an analog selector S1. DA converter DC and comparator CPC have the same configurations as DA converters DC1 to DCm and comparators CPC1 to CPCm, respectively, shown in FIG.

  The analog selector S1 is a member corresponding to the first selector described in the claims, and has m input terminals and one output terminal. Each input terminal of the analog selector S1 is connected to one end of each of the row lines LC1 to LCm. A connection point between each input terminal of the analog selector S1 and one end of each row line LC1 to LCm is connected to the power supply Vcc via a resistor Rd. The + input terminal of the comparator CPC is connected to the output terminal of the analog selector S1, and the output terminal of the DA converter DC is connected to the output terminal of the analog selector S1 via the resistor Rc.

  The analog selector S1 alternatively connects the DA converter DC and the comparator CPC sequentially with one end of each row line LC1 to LCm based on a select signal SEL1 from a CPU (not shown). Thereby, the DA converter DC can drive each row line LC1-LCm sequentially. Further, output voltages from the respective row lines LC1 to LCm are sequentially input to the + input terminal of the comparator CPC.

  The DA converter DC switches the output voltage according to the connected row lines LC1 to LCm. Specifically, the DA converter DC sequentially switches the output voltage so that the output voltage to the row line LC1 <the output voltage to the row line LC2 <... <The output voltage to the row line LCm.

  As described above, the row line driver 34 includes the analog selector S1 so that the DA converter DC and the comparator CPC can be shared. Therefore, the configuration of the row line driver 34 can be further simplified as compared with the row line driver 14 shown in FIG.

  Next, a configuration in which one DA converter for driving the column lines LS1 to LSn and one comparator to which voltages from the column lines LS1 to LSn are input will be described with reference to FIG.

  FIG. 10 is a diagram illustrating a configuration of a column line driver 33 according to another modification of the present embodiment. The column line driver 33 includes one DA converter DS and one comparator CPS, and further includes an analog selector S2. DA converter DS and comparator CPS have the same configurations as DA converters DS1 to DSn and comparators CPS1 to CPSn, respectively, shown in FIG.

  The analog selector S2 is a member corresponding to the second selector described in the claims, and has n input terminals and one output terminal. Each input terminal of the analog selector S2 is connected to one end of each of the column lines LS1 to LSn. A connection point between each input terminal of the analog selector S2 and one end of each column line LS1 to LSn is connected to the power supply Vcc via a resistor Rb. Further, the negative input terminal of the comparator CPS is connected to the output terminal of the analog selector S2, and the output terminal of the DA converter DS is connected to the output terminal of the analog selector S2 via the resistor Ra.

  The analog selector S2 alternatively and sequentially connects the DA converter DS and the comparator CPS to one end of each column line LS1 to LSn based on a select signal SEL2 from a CPU (not shown). Thereby, the DA converter DS can sequentially drive the column lines LS1 to LSn. In addition, output voltages from the column lines LS1 to LSn are sequentially input to the negative input terminal of the comparator CPS.

  The DA converter DS switches the output voltage according to the connected column lines LS1 to LSn. Specifically, the DA converter DS sequentially switches the output voltage so that the output voltage to the column line LS1 <the output voltage to the column line LS2 <... <The output voltage to the column line LSn.

  As described above, the column line driver 33 includes the analog selector S2, so that the DA converter DS and the comparator CPS can be shared. Therefore, the configuration of the column line driver 33 can be further simplified as compared with the column line driver 13 shown in FIG.

[Summary of Embodiment]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The touch position detection device according to the present invention can be used for an input device of an ATM (automated teller machine) or a programmable display of a financial institution.

DESCRIPTION OF SYMBOLS 1 Touch position detection apparatus 2 Touch panel 11 Touch position detection apparatus BC1-BCm Three state buffer (row line drive part)
BS1 to BSn Three-state buffer (column line drive unit)
CPC1 to CPCm Comparator (row line detector)
CPS1 to CPSn comparators (column line detector)
DC1 to DCm DA converter (row line drive unit)
DS1 to DSn DA converter (column line drive unit)
LC1 to LCm Row line LS1 to LSn Column line RC1 to RCm Row line resistance RS1 to RSn Column line resistance S1 Analog selector (first selector)
S2 Analog selector (second selector)
VC threshold voltage (first threshold voltage)
VS threshold voltage (second threshold voltage)

Claims (5)

A touch panel having a plurality of column lines arranged in a row direction and a plurality of row lines arranged in the column direction apart from the column lines;
A column line driver that sequentially drives each column line by applying a voltage to one end of each column line;
A row line driver that sequentially drives each row line by applying a voltage to one end of each row line;
When the column line driver is driving each column line, the voltage input from the one end of each row line is compared with a first threshold voltage, thereby making contact with the column line by pressing the touch panel A line line detection unit for detecting a line line
When the row line driving unit is driving each row line, the voltage input from the one end of each column line is compared with a second threshold voltage, thereby making contact with the row line by pressing the touch panel. A column position detection unit that detects a column line, and a touch position detection device comprising:
When any one of the column lines is in contact with any one of the row lines, a voltage input to the row line detection unit from the one end of the row line contacting the column line, and the row line It is characterized by comprising input voltage steady means for making the voltage input to the column line detector from the one end of the column line in contact with each other constant regardless of the combination of the column line and the row line in contact with each other. Touch position detection device. The input voltage steady means is:
When any one of the column lines is in contact with any one of the row lines, a resistance value between the column line driving unit and the contact position, and between the row line detection unit and the contact position are set. The sum of the resistance value and the sum of the resistance value between the row line driving unit and the contact position and the resistance value between the column line detection unit and the contact position are the column line and the row line in contact with each other. Regardless of the combination of the above, each is a resistance value steady means for making it constant,
The resistance value steady means includes the same number of column line resistors as the column lines, and the same number of row line resistors as the row lines,
One end of each column line resistor is connected to the column line driver and the column line detector, and the other end of each column line resistor is connected to the one end of each column line,
One end of each row line resistor is connected to the row line driver and the row line detector, and the other end of each row line resistor is connected to the one end of each row line,
When the column line driver is driving each column line, the voltages applied to one end of each column line resistor are equal to each other,
The voltage applied to one end of each row line resistance when the row line driver is driving each row line is equal to each other,
Each column line resistance has a smaller resistance value as the order of arrangement from the one end side of the row line of the connected column line is larger,
2. The touch position detection device according to claim 1, wherein each row line resistance has a smaller resistance value as the order of arrangement from the one end side of the column line of the row line to be connected is larger. The input voltage steady means is:
Column line application voltage setting means for setting the voltage applied by the column line driving unit to be higher for the column line having a larger order of arrangement from the one end side of the row line,
The row line application voltage setting means for setting the voltage applied by the row line driving unit to be higher for a row line having a larger order of arrangement from the one end side of the column line. The touch position detection device according to 1. Each of the column line driving unit, the row line driving unit, the row line detecting unit, and the column line detecting unit is provided.
A first selector that alternatively connects the row line driving unit and the row line detection unit alternatively to one end of each row line resistor;
The touch position detection device according to claim 2, further comprising: a second selector that selectively connects the column line driving unit and the column line detection unit to one end of each column line resistor. Each of the column line driving unit, the row line driving unit, the row line detecting unit, and the column line detecting unit is provided.
A first selector that alternatively connects the row line driving unit and the row line detection unit to one end of each row line sequentially;
The touch position detection device according to claim 3, further comprising a second selector that selectively connects the column line driving unit and the column line detection unit to one end of each column line.

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