JP2015222603A - Touch sensor device and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a static capacitive type touch sensor device and electronic device including the touch sensor device that prevent a touch-off faulty determination.SOLUTION: A touch sensor device comprises: a touch panel that has a static capacitor between an indication body and the touch panel formed; and a signal calculation mechanism that calculates an output value of a signal corresponding to a size of a static capacitor. When a first distance between the indication body and the touch panel when it is determined that the indication body and the touch panel depart in a case where the distance between the indication body and the touch panel monotonously increases after the indication body is caused to get closer to the touch panel and the indication body is determined to have come into contact with the touch panel, is compared with a second distance between the indication body and the touch panel when it is determined that the indication body and the touch panel depart in a case where the distance therebetween gradually elongates as repeating increase and reduction in the distance therebetween after the indication body is caused to get closer to the touch panel and the indication body is determined to have come into contact with the touch panel, the first distance is shorter than the second distance.

Description

(Related Application) This application claims domestic priority based on the previous patent application 2010-231291 (filing date October 14, 2010) as a basic application. The entire description of the earlier application is incorporated herein by reference.
The present invention relates to a capacitive touch sensor device. The present invention also relates to an electronic device provided with the touch sensor device.

  The touch sensor device is a device that detects position coordinates pointed by using an indicator such as a fingertip or a pen, or the presence or absence of a pointing operation, and is generally referred to as a liquid crystal display (hereinafter referred to as “LCD”). ) And a plasma display (hereinafter referred to as “PDP” (Plasma Display Panel)).

  An easy-to-use man-machine interface is realized by inputting the output of the touch sensor device to a computer and controlling the display content of the display device or the device by the computer. Currently, it is widely used in daily life such as game machines, portable information terminals, ticket vending machines, ATMs (Automated Teller Machines), car navigation systems, and the like. As the performance of computers and the network connection environment become widespread, services provided by electronic devices are diversified, and accordingly, the needs for display devices equipped with touch sensor devices continue to expand.

  As a method of the touch sensor device, a capacitance method, a resistance film method, an infrared method, an ultrasonic method, an electromagnetic induction method, and the like are known. Among touch sensor devices, the capacitive touch sensor device can detect the contact of the indicator through thin glass or plastic, etc., and it can be detected without pressing strongly, so repeated input Excellent durability against contact. In this way, capacitive touch sensor devices are widely used in many application areas such as industrial products and white goods.

  Capacitive touch sensor devices are classified into a projected type and a surface capacitive type.

  The projection type is a system in which XY transparent electrodes are formed in a matrix shape. The X transparent electrode and the Y transparent electrode are formed through glass or an insulating layer. When the indicator approaches the XY transparent electrode, the capacitance between the electrodes increases, and the static of the XY line is increased. The controller detects the change in the electric capacity and detects the position of the indicator.

  On the other hand, the surface type is composed of an insulating substrate, a uniform transparent conductive layer formed on the surface, and a thin insulating layer (protective layer) formed on the upper surface. When the touch sensor device is driven, an alternating voltage is applied to the four corners of the transparent conductive layer. When the surface of the touch sensor device is touched with the indicator, a minute current flows through the indicator through the electrostatic capacitance formed by the transparent conductive layer and the indicator. This current flows from each of the four corners of the transparent conductive layer to the point where the indicator contacts. Then, the signal processing circuit detects the presence or absence of contact from the sum of the respective currents. Also, the coordinates of the contact position are calculated from the ratio of the respective currents. For example, Patent Document 1 discloses a technique related to such a surface mold.

  Next, an example of a method for determining the presence or absence of contact will be described. First, the capacitance formed in the transparent conductive layer is converted into a signal proportional to the signal processing circuit. Next, a signal is acquired at a constant frequency, and the signal is compared with a predetermined threshold value. After the indicator touches the surface of the touch sensor device, the signal rises and immediately after the signal becomes larger than the threshold value, the touch-on determination is made. Further, the touch-off determination is made immediately after the indicator becomes detached from the surface of the touch sensor device and immediately after the signal becomes smaller than the threshold value. For example, Patent Documents 2 to 6 and Non-Patent Document 1 disclose techniques for preventing erroneous determination.

  Patent Document 2 discloses a capacitive digital touch panel that allows a stable switch operation by separately setting threshold values for determining from OFF to ON and from ON to OFF as switches.

  Patent Document 3 discloses a touch gesture detection method for a touch panel that includes a step of calculating a time for detaching an article from the touch panel and a step of sending a gesture signal if the detachment time is longer than a reference time. . Further, Patent Document 4 discloses a capacitive touch panel article detection method that displays a contact of an article with a touch panel if the amount of sensitivity maintains an increasing tendency within a set time.

  Non-Patent Document 1 discloses a programmable controller that incorporates an adaptive threshold and sensitivity algorithm for automatic adjustment. This algorithm continuously monitors the output level of each sensor, and in the sensor area covered by the user. It is described to automatically rescale the threshold level in proportion.

  Patent Document 5 discloses a reference signal storage unit that stores a reference signal for determining that a human finger or the like is not in contact with a switch, a reference signal stored in the reference signal storage unit, and a touch sensor. Switch input determining means for determining that a human finger or the like has touched the switch when the amount of change is greater than or equal to the regulation value or greater than the regulation value, and the reference signal storage means A touch panel is disclosed that updates a reference signal stored based on a switch signal output from a touch sensor when it is determined by a switch input determination means that a human finger or the like is not in contact with the switch. ing.

  Patent Document 6 discloses a touch sensor, an average value calculating unit that calculates an average value of output voltages sent from the output unit of the touch sensor, a threshold value calculating unit that calculates a threshold value based on the average value, and an output voltage. Comparing and determining means for outputting a determination signal when the output voltage is determined to exceed the threshold value by comparing with the threshold value, and the average value calculating means periodically samples the output voltage in the recording unit. There is disclosed a touch sensor device comprising sampling means for recording as output voltage data, and calculating means for calculating a moving average value of the output voltage recorded in the recording section and sending it to a threshold value calculating means.

JP-T56-500230 Japanese Patent Laying-Open No. 2005-18669 JP 2007-52639 A JP 2007-26065 A JP 2007-208682 A JP 2009-169697 A

Analog Devices, Inc., Programmable Controller AD7147 data sheet, page 25, Internet <URL: http://www.analog.com/static/imported-files/jp/data_sheets/AD7147_jp.pdf> [2010 September Month 1 search]

  The following analysis is given from the perspective of the present invention.

  According to the finding of the present inventor, the indicator touches the surface of the touch panel, and the touch-off determination may be erroneously performed during the drag operation after the touch-on determination. Here, the indicator means a conductive one that forms a capacitance equivalent to that of a finger or a finger. The indicator may be any as long as it can input an instruction to the touch sensor. Examples of the indicator include a finger (including a finger wearing a glove), a pen, and the like. Touch-on refers to a state in which the indicator is in contact with the touch panel for the purpose of inputting instructions. Touch-off refers to a state where there is no contact between the indicator for the purpose of inputting an instruction and the touch panel. Further, the drag operation is an operation in which the indicator is brought into contact with the surface of the touch panel and the indicator is displaced. This is because the user may unintentionally touch the touch panel with a part other than the indicator during the drag operation. For this reason, the capacitance formed by the indicator and the transparent conductive layer is not sufficient. Due to the decline. Another cause is that the capacitance may fluctuate during the drag operation.

  The indicator is an elastic body such as a fingertip, and the indicator and the surface of the touch panel come into contact with each other, and the indicator receives a repulsive force by pushing the indicator with a certain amount of force. By doing so, the indicator is deformed along the surface of the touch panel, the contact area between the indicator and the surface of the touch panel is increased, and the capacitance is increased accordingly.

  On the other hand, in the drag operation, the indicator and the surface of the touch panel come into contact with each other, and the indicator is displaced on the surface of the touch panel, so that friction occurs between the indicator and the surface of the touch panel. In order to weaken this friction and move the indicator smoothly on the surface of the touch panel, the user tends to unconsciously reduce the pressing force (contact pressure) of the indicator. For this reason, the repulsive force which an indicator receives from the touch panel surface becomes weak, and the contact area of the indicator and the surface of a touch panel becomes small.

  In addition, since the force of pressing the surface of the touch panel with the indicator tends to fluctuate during the drag operation, the capacitance formed by the transparent conductive layer and the indicator fluctuates. In addition, during the drag operation, the indicator may slightly float with respect to the surface of the touch panel due to friction between the indicator and the surface of the touch panel, and the contact area between the indicator and the surface of the touch panel may vary. The capacitance fluctuates.

  From the above, during the drag operation, the contact area between the indicator and the surface of the touch panel is relatively small, and the contact area fluctuates. Is receiving. Therefore, the touch-off determination may be performed even during the drag operation, or the touch-off determination may not be performed even if the touch-off is performed after the drag operation.

  In the touch sensor device that compares the threshold value of the touch-on determination and the threshold value of the touch-off determination and compares the threshold value with a constant and compares the signal with the threshold value, first, the indicator contacts the surface of the touch panel, and the signal is transmitted. When it becomes larger than the threshold value, a touch-on determination is made. However, if the signal decreases as described above due to the drag operation, the signal may become smaller than the threshold value and a touch-off determination may be made. That is, the touch-off determination is made even though the indicator is in contact with the surface of the touch panel.

  On the other hand, in the touch sensor device in which the signal during the drag operation is measured in advance and the threshold value is set lower than the signal, even if the indicator is not in contact with the surface of the touch panel, the indicator, the palm, etc. In this case, the signal tends to be larger than the threshold value, and touch-on determination may be made.

  Therefore, both the device that makes the touch-on determination threshold value equal to the touch-off determination threshold value and the device that predicts the signal in advance will erroneously determine the presence or absence of an instruction input.

  In the background art described in Non-Patent Document 1, as a countermeasure against the difference in the signal magnitude associated with contact between users, the threshold value for the next touch determination is automatically calculated based on the signal associated with the previous contact. Set with. However, if the signal associated with the previous contact is large and the threshold value calculated based on this signal is high, even if the signal is once greater than the threshold value and touch-on determination is made, In this case, erroneous touch-off determination is likely to occur. That is, the adaptive threshold value of Non-Patent Document 1 has a problem that the next threshold value becomes an inappropriate value depending on the difference between the signal accompanying the previous contact and the signal accompanying the next contact.

  In the capacitance type digital touch panel described in Patent Document 2, the touch-off determination threshold is set lower than the touch-on determination threshold. However, for example, if the palm remains approaching the surface of the touch panel even if the fingertip that is the indicator is released after the touch-on determination is made, the signal remains higher than the touch-off determination threshold value, and the touch-off determination may not be performed.

  In the hand gesture detection method described in Patent Document 3 and the capacitive touch panel article detection method described in Patent Document 4, a touch-off determination is made when a decrease in the detection signal continues for a predetermined time. However, the detection signal may decrease when the fingertip is in contact with a drag operation or the like, the detection signal may be lower than the threshold value for touch-off determination, and the state may continue for a predetermined time. In this case, the touch-off state is determined to be a touch-off state. Even when the fingertip as the indicator is removed, even if the palm remains approaching for a predetermined time, the state in which the detection signal is larger than the touch-off determination threshold value continues for a predetermined time and the touch-off determination may not be performed.

  In the touch panel described in Patent Document 5, the reference signal is updated to the switch signal at the time of touch-off, and the erroneous determination associated with the drag operation cannot be eliminated. Further, the change amount of the switch signal at the time of touch-off is small, and the change rate is also low. On the other hand, when the touch is turned on, the change amount of the switch signal is large and the change rate is also high. Therefore, it is also difficult to suppress erroneous determination at the time of touch-on with the touch panel described in Patent Document 5.

  In the touch sensor device described in Patent Document 6, when the indicator is gradually separated from the touch panel, the threshold value also follows and decreases. However, in such a case, the signal always becomes higher than the threshold value, and even if the indicator is released, the touch-off determination is not made when a palm or the like is present nearby.

  An object of one aspect of the present invention is to provide a capacitive touch sensor device that prevents erroneous touch-off determination. Another object of the present invention is to provide an electronic device including the touch sensor device.

  According to a first aspect of the present invention, a touch panel having a capacitance formed between the indicator and a signal calculation mechanism that calculates an output value of a signal corresponding to the magnitude of the capacitance is provided. The indicator and the touch panel when the distance between the indicator and the touch panel is monotonously increased after it is determined that the indicator and the touch panel are in contact with each other. The first distance between the indicator and the touch panel when it is determined that the indicator has been released, and the indicator is determined to have contacted the touch panel by bringing the indicator close to the touch panel. When the distance between the body and the touch panel is gradually increased while repeating the increase and decrease, the indicator and the touch panel when it is determined that the indicator and the touch panel are separated. When compared with the second distance between Le, the said first distance is a touch sensor device is provided shorter than the second distance.

  According to the second aspect of the present invention, when the indicator is brought close to the touch panel and it is determined that the indicator and the touch panel are in contact with each other, the indicator is monotonously increased. And the first distance between the indicator and the touch panel when it is determined that the touch panel has been released, and the indicator and the touch panel are determined to be in contact with each other by bringing the indicator close to the touch panel. When the distance is gradually increased while repeating the increase and decrease, the first distance is the second distance when comparing the second distance between the indicator and the touch panel when it is determined that the indicator and the touch panel are separated. A touch sensor device shorter than the distance is provided.

  According to the 3rd viewpoint of this invention, an electronic device provided with the touch sensor apparatus which concerns on the said 1st viewpoint is provided.

  The present invention has at least one of the following effects.

  According to the present invention, the threshold value is updated according to the change in the signal during the drag operation, so that it is possible to suppress erroneous touch-off determination during the drag operation.

1 is a schematic block diagram of a touch sensor device according to a first embodiment of the present invention. The flowchart for demonstrating the operation | movement and control method of the touch sensor apparatus which concerns on 1st Embodiment of this invention, and the program for operating a touch sensor apparatus. 1 is a schematic perspective view of an electronic device according to the present invention. FIG. 4 is a schematic cross-sectional view of the electronic apparatus of the present invention along the line IV-IV in FIG. 3. The equivalent circuit diagram of the touch sensor function in the touch sensor apparatus of this invention. The schematic block diagram of the electric current detection circuit in the touch sensor apparatus of this invention, and its peripheral function. An example of the voltage waveform of the operation | movement in the touch sensor apparatus of this invention. The flowchart for demonstrating the operation | movement and control method of the touch sensor apparatus which concerns on 2nd Embodiment of this invention, and the program for operating a touch sensor apparatus. The schematic block diagram of the touch sensor apparatus which concerns on 3rd Embodiment of this invention. The flowchart for demonstrating the operation | movement and control method of the touch sensor apparatus which concerns on 3rd Embodiment of this invention, and the program for operating a touch sensor apparatus. The schematic exploded perspective view of the electronic device which concerns on 4th Embodiment of this invention provided with the touch sensor apparatus of this invention. FIG. 12 is a schematic plan view of the electronic device shown in FIG. 11. The voltage timing chart in the electronic device of 4th Embodiment. The plane schematic diagram which shows the opposing board | substrate of the electronic device which concerns on 5th Embodiment incorporating the touch sensor apparatus of this invention. The schematic sectional drawing in alignment with the XV-XV line | wire of FIG. The voltage timing chart in the electronic device of 5th Embodiment. The schematic block diagram of the touch sensor apparatus which concerns on 6th Embodiment of this invention. The flowchart for demonstrating the operation | movement and control method of the touch sensor apparatus which concerns on 6th Embodiment of this invention, and the program for operating a touch sensor apparatus. The schematic sectional drawing of the touch sensor apparatus which concerns on 7th Embodiment. The schematic plan view of the touch sensor apparatus which concerns on 7th Embodiment. In Example 1, it is a graph which shows the simulation result of the change of the detection signal value h (iT) at the time of changing the approach states, such as a fingertip and a palm, with respect to a touch panel, and the output value f (iT) of a signal. In Example 1, it is a graph which shows the measurement result of the change of the detection signal value h (iT) at the time of changing approach states, such as a fingertip and a palm, with respect to a touch panel, and the output value f (iT) of a signal. 10 is a graph showing a simulation result of a change in the first threshold value (Th1) in Example 2. 10 is a graph showing measurement results of changes in the first threshold value (Th1) in Example 2. 10 is a graph showing simulation results of changes in signal output values, first threshold values, and second threshold values in Example 3. 9 is a graph showing measurement results of changes in signal output values, first threshold values, and second threshold values in Example 3. The graph which shows the simulation result of the change of the output value of a signal in Example 4, a difference value, a 1st threshold value, and a 2nd threshold value. The graph which shows the measurement result of the change of the output value of a signal in Example 4, a difference value, a 1st threshold value, and a 2nd threshold value. The graph which shows the simulation result of the change of the output value of a signal in Example 5, a difference value, a 1st threshold value, and a 2nd threshold value. The graph which shows the measurement result of the change of the output value of a signal in Example 5, a difference value, a 1st threshold value, and a 2nd threshold value. The graph which shows the simulation result of the change of the output value of a signal in case the thickness of the cover glass in Example 6 differs. The graph which shows the change of the output value of the signal with respect to the thickness of the cover glass in Example 6. FIG. The graph which shows the measurement result of the change of the output value of a signal in case the thickness of the cover glass in Example 6 differs. The graph which shows the change of the difference value with respect to the thickness of the cover glass in Example 6. FIG. The graph which shows the simulation result of the change of the output value of a signal in Example 6, a difference value, and a 1st threshold value. The graph which shows the measurement result of the output value of a signal in Example 6, a difference value, and the change of a 1st threshold value. FIG. 10 is a schematic perspective view of a testing machine used for measurement in Example 7. In Example 7, the graph which shows the change of the output value of a signal at the time of raising a pointer monotonously, a 1st threshold value, and distance. In Example 7, the graph which shows the change of the output value of a signal, a 1st threshold value, and distance at the time of separating an indicator from the surface of a touch panel, repeating raising / lowering of an indicator. In Example 8, it is a graph which shows transition of the output value of a channel signal. The graph which shows transition of the sum of the output value of four channel signals. The figure which added description to FIG. FIG. 43 shows measurement results of the signal output value f [iT] and the first threshold Th1.

  The preferable form of each said viewpoint is described below.

  According to a preferred form of the first aspect, when the increase in the output value of the signal is detected, the threshold value calculation mechanism updates the first threshold value to be smaller than the output value of the signal determined to have increased. To do.

  According to the preferable form of the first aspect, the touch sensor device further includes a signal comparison mechanism that determines whether or not the output value of the signal has increased in the first unit time of 0.02 seconds to 0.2 seconds. .

  According to the preferable form of the first viewpoint, the contact determination mechanism uses a second threshold value that is a constant for determining whether or not the indicator and the touch panel are in contact with each other.

  According to the preferable form of the first viewpoint, the touch sensor device further includes a difference calculation mechanism that calculates a first difference value that is a magnitude of a change in signal per second unit time. The contact determination mechanism determines that the contact has been released when the absolute value of the first difference value is greater than the third threshold value in determining whether the indicator and the touch panel have been removed.

  According to the preferable form of the first aspect, the contact determination mechanism determines whether the indicator and the touch panel are separated from each other by comparing the output value of the signal with the threshold value when the absolute value of the first difference value is the first value. This is performed when the threshold is 3 or less.

  According to the preferable form of the first viewpoint, the touch sensor device further includes a difference calculation mechanism that calculates a first difference value that is a magnitude of a change in signal per second unit time. The contact determination mechanism determines that the contact is made when the absolute value of the first difference value is greater than the third threshold value in determining whether the indicator and the touch panel are in contact.

  According to the preferable form of the first viewpoint, the contact determination mechanism determines whether the indicator and the touch panel are in contact with each other. In the comparison between the output value of the signal and the threshold, the absolute value of the first difference value is This is performed when it is equal to or less than the third threshold.

  According to a preferred form of the first aspect, the second unit time is a signal change time when the indicator touches the touch panel or a signal change time when the indicator leaves the touch panel.

  According to a preferred form of the first aspect, the second unit time is 0.008 seconds to 0.1 seconds.

  According to the preferable form of the first aspect, the touch sensor device calculates a baseline according to the size of the capacitance formed on the touch panel in a state where the capacitance by the indicator is not affected. And a calculation mechanism. The signal calculation mechanism calculates the output value of the signal from the capacitance formed by the indicator and the baseline.

  According to the preferable form of the first viewpoint, the touch sensor device further includes a change determination mechanism that determines the magnitude of the change in the signal. The difference calculation mechanism calculates a second difference value that is a change in the signal in the third unit time. The change determination mechanism determines whether or not the signal changes due to the approach of the indicator by comparing the second difference value and the fourth threshold value.

  According to the preferable form of the first viewpoint, the second unit time is from the time when the second difference value is equal to or greater than the fourth threshold value to the time when the second difference value is equal to or less than the fourth threshold value.

  According to the preferable form of the first viewpoint, the upper limit value of the second unit time is set between 32 milliseconds and 80 milliseconds.

  According to the preferable form of the first aspect, the fourth threshold value is a value obtained by dividing the third threshold value by the upper limit value of the second unit time.

  According to the preferable form of the first viewpoint, the touch sensor device further includes a position calculation mechanism that calculates position coordinates where the indicator and the touch panel come into contact. The signal calculation mechanism calculates the output value of the signal based on the signal of each channel of the touch panel. The position calculation mechanism calculates position coordinates based on a value obtained by subtracting a signal component accompanying the approach of an element other than the indicator from the signal of each channel.

  According to the preferred form of the first viewpoint, the position calculation mechanism inserts the signal component accompanying the approach of an element other than the indicator by inserting the second difference value equal to or smaller than the fourth threshold value and the second unit time. calculate.

  According to a preferred embodiment of the third aspect, the electronic device includes a counter electrode that also serves as a conductive layer that forms a capacitance with the indicator, a wiring, and a liquid crystal interposed between the counter electrode and the wiring. And a switch unit that floats at least part of the wiring.

  According to a preferred embodiment of the third aspect, the electronic device includes a counter electrode that also serves as a conductive layer that forms a capacitance with the indicator, a wiring, and a liquid crystal interposed between the counter electrode and the wiring. And a switch portion for simultaneously applying an AC voltage applied to the conductive layer to at least a part of the wiring.

  According to a preferred embodiment of the third aspect, the electronic device includes a counter electrode, a wiring, a liquid crystal interposed between the counter electrode and the wiring, and a conductive layer that forms a capacitance between the indicator. And an insulating substrate provided between the counter electrode and the conductive layer, and a switch unit that simultaneously applies an AC voltage applied to the surface of the conductive layer to the counter electrode.

  According to the fourth aspect of the present invention, the step of calculating the output value of the signal according to the magnitude of the capacitance formed between the indicator and the touch panel, and the case where the output value of the signal is greater than the second threshold value. A step of determining that the indicator and the touch panel are in contact; a step of determining that the indicator and the touch panel are detached when the output value of the signal is equal to or less than the first threshold; and the indicator and the touch panel A step of detecting whether the output value of the signal has increased in the first unit time between the time after determining contact with the device and the time of determining separation, and when the output value of the signal has increased in the first unit time. A method of controlling the touch sensor device, comprising: updating the first threshold value.

  According to the preferable form of the fourth aspect, in the step of updating the first threshold value, the first threshold value is set to a value smaller than the output value of the signal determined to have increased.

  According to a preferred form of the fourth aspect, the first unit time is 0.02 seconds to 0.2 seconds.

  According to a preferred form of the fourth aspect, the second threshold value is a constant.

  According to a preferred form of the fourth aspect, the method for controlling the touch sensor device further includes a step of calculating a first difference value that is a magnitude of a change in signal per second unit time. In the step of determining the contact between the indicator and the touch panel, it is determined that the indicator and the touch panel are in contact when the absolute value of the first difference value is greater than the third threshold value. In the step of determining whether the indicator and the touch panel are detached, it is determined that the indicator and the touch panel are separated when the absolute value of the first difference value is smaller than the third threshold value.

  According to the preferable form of the fourth viewpoint, in the step of determining the contact between the indicator and the touch panel, when the absolute value of the first difference value is equal to or smaller than the third threshold value, the second threshold value and the output value of the signal are Compare In the step of determining separation between the indicator and the touch panel, when the absolute value of the first difference value is equal to or greater than the third threshold value, the first threshold value is compared with the output value of the signal.

  According to a preferred form of the fourth aspect, the second unit time is a signal change time when the indicator touches the touch panel or a signal change time when the indicator leaves the touch panel.

  According to the preferable form of the fourth aspect, the second unit time is 0.008 seconds to 0.1 seconds.

  According to the fifth aspect of the present invention, there is provided a program for causing a touch sensor device to execute the touch sensor device control method according to the fourth aspect.

  Here, the touch panel only needs to have a function of detecting contact with the indicator. The touch panel includes, for example, a touch switch that detects only the presence or absence of contact with the indicator and a touch panel that detects not only the presence or absence of contact with the indicator but also a drag operation.

  A touch sensor device according to a first embodiment of the present invention will be described. FIG. 1 shows a schematic block diagram of a touch sensor device according to a first embodiment of the present invention. The touch sensor device 100 includes a touch panel 101 as a touch sensor that is input by a user with an indicator such as a fingertip, and a signal acquisition mechanism 102 that acquires an output signal of the touch panel 101. In addition, the touch sensor device 100 calculates a baseline for calculating a signal output value based on an output from the signal acquisition mechanism 102, and a baseline obtained by the reference calculation mechanism 103. And a reference storage mechanism 104 for storing. Furthermore, the touch sensor device 100 calculates a signal output value for determining touch-on / off based on the output obtained by the signal acquisition mechanism 102 and the baseline stored in the reference storage mechanism 104. 105, a threshold value storage mechanism 109 that stores a threshold value for determining touch-on / off, and compares the threshold value stored in the threshold value storage mechanism 109 with the output value of the signal calculated by the signal calculation mechanism 105. And a contact determination mechanism 110 for determining OFF. Furthermore, the touch sensor device 100 compares the output value of the signal calculated by the signal calculation mechanism 105 with the output value of the signal stored in the signal storage mechanism 107, and the result of the signal comparison mechanism 106. And a threshold value calculation mechanism 108 that calculates the threshold value accordingly. The threshold value calculated by the threshold value calculation mechanism 108 is stored in the threshold value storage mechanism 109.

  Next, an operation and control method of the touch sensor device 100 and a program for operating the touch sensor device 100 will be described. FIG. 2 shows a flowchart for explaining the operation and control method of the touch sensor device and the program for operating the touch sensor device according to the first embodiment of the present invention. For the sake of convenience, the description will be limited to an algorithm that determines the presence or absence of a touch without detecting the position (coordinates) of the touch. In FIG. 2, FIG. 8, and FIG. 10, the output value f [iT] of the signal is represented as signal f [iT].

  First, after the program starts, i = 1 is set (S100). Here, i (natural number) indicates a determination (loop) of the i th touch determination from the start of the program. Here, the determination of touch determination includes determination of touch-on determination and touch-off determination.

  Next, when i = 1, the contact determination mechanism 110 makes a touch-off determination by the initial setting of the determination (S101). Immediately after the program starts, it is assumed that the indicator is not in contact with the surface of the touch panel. When i ≧ 2, S101 means that the touch determination mechanism 110 has performed touch-off determination by touch determination.

  Here, the invention according to the first embodiment is an invention related to touch-off determination, and in the present embodiment, touch-on determination means will be briefly described. The signal acquisition mechanism 102 acquires a signal from the touch panel 101, and the signal calculation mechanism 105 corrects the output value of the acquired signal based on the baseline stored in the reference storage mechanism 104, and outputs the signal output value f [ iT] (S102). Here, T is the period of judgment for touch determination, that is, the reciprocal of the operating frequency of the touch sensor. For example, when the operating frequency of the touch sensor is 40 Hz, T = 25 msec. Next, the contact determination mechanism 110 compares the signal output value f [iT] with the first threshold value Th1 stored in the threshold value storage mechanism 109 (S103), and the signal output value f [iT] is greater. If larger (f [iT]> Th1), a touch-on determination is made (S106). After S103, i is incremented by one (S104, S105). When i = 1, the first threshold Th1 stored in the threshold storage mechanism 109 is used as an initial setting. When i ≧ 2, if the first threshold Th1 has been updated in S110 described later, the updated first threshold Th1 is used.

  After the touch-on determination (S106), in the determination of the i-th touch determination, the output value f [iT] of the signal is acquired in the same manner as S102 (S107).

  Next, the signal comparison mechanism 106 compares the output value f [iT] of the signal acquired in S107 with the output value f [(iq) T] of the signal acquired in the (i−q) th determination. (S108). Here, f [(i−q) T] is signal data acquired in the (i−q) -th loop and held in the signal storage mechanism 107. For example, the signal comparison time (first unit time) can be 3T (that is, q = 3). For example, when T = 25 msec, the first unit time is 75 msec. However, when i is (q + 1) or less, for example, q = 3, and when i is 4 or less, the signal output value f [(i−q) T] is changed to the signal output value f [(1T). ]. When the output value f [iT] of the signal is larger than the output value of the signal output value f [(i−q) T], the signal storage mechanism 107 sets the output value f [iT] of the signal to “ Stored as signal c ". In FIG. 2, q = 3.

  Next, the threshold value calculation mechanism 108 calculates a new first threshold value Th1 based on the signal c in contact and stores it in the threshold value storage mechanism 109 (S110). Here, the calculation formula of the first threshold Th1 is Th1 = c × α. α is a sensitivity and is set in advance in a range of 0 <α <1 and is preferably 0.5 to 0.7. If α is too high, even if the fingertip is in contact with the surface of the touch panel, the signal output value f [iT] tends to be smaller than Th1, and a touch-off determination may be made. On the other hand, if α is too low, the output value f [iT] of the signal remains larger than the first threshold Th1 and the touch-off determination is not made when the palm is close even if the fingertip is detached from the surface of the touch panel. is there. Next, i is counted up by one, and the process returns to S107. In this case (when f [iT]> f [(i−q) T]), S112 and the like are omitted.

  In the flowchart shown in FIG. 2, after the touch-on determination (S106), the signal output value f [iT] is newly acquired in S107, and then the first threshold Th1 is updated in S110. Instead, the output value f [iT] of the signal used for the touch-on determination in S103 may be set as the output value f [iT] of the signal in S108. That is, in S108, the output value f [iT] of the signal used for the touch-on determination in S103 is compared with the output value f [(iq) T] of the signal acquired for the (i-q) th time, and the output value When f [iT] is larger, the first threshold Th may be updated in S110.

  In S108, when the signal output value f [iT] is equal to or less than the signal output value f [(iq) T] obtained in the (i−q) th determination, the contact determination mechanism 110 outputs the signal. The value f [iT] is compared with the first threshold Th1 (S112). When the output value f [iT] of the signal is equal to or greater than the first threshold Th1, i is counted up by one (S113), and the process returns to S107. In this case, the touch-off determination is not made.

  On the other hand, if the output value f [iT] of the signal is smaller than the first threshold Th1, i is incremented by one (S114), and then the contact determination mechanism 110 determines the touch-off (S101). The process exits the loop for determining whether or not the touch-off is determined, and proceeds to the loop for determining whether or not the touch-on is determined.

  If the process has passed through S110 before returning to S101, that is, if the first threshold Th1 has been updated, the updated first threshold Th1 is used in the next S103.

  In S108, the output value of the i-th signal is compared with the output value of the (i-q) -th signal, and q (natural number) is the unit time (i.e., (i-q) T to i-T). 1 unit time), that is, qT is preferably set to 20 msec to 200 msec.

  First, the grounds for the upper limit of the first unit time will be described. According to an example described later, when the increase / decrease of the signal being dragged is viewed as a sine wave voltage, the frequency is approximately 2.5 Hz. In order to correctly sample this tendency (waveform), it is necessary to sample at a frequency higher than twice the bandwidth of the frequency component of the waveform (this is called the sampling theorem). Twice the frequency of signal increase / decrease is 5 Hz, and since the reciprocal of the sampling frequency is the first unit time, the first unit time for determining signal increase / decrease is preferably 200 msec or less.

  Next, the grounds for the lower limit of the first unit time will be described. As the operation speed at which the indicator is detached from the surface of the touch panel becomes slower, the slope of signal decrease becomes smaller. If there is a period in which the signal fluctuation due to the noise component is large compared to the amount of decrease in the first unit time, the signal does not monotonously decrease, and the first threshold Th1 is updated every time the signal increases. Will be. Other noise components are superimposed on the component whose signal changes due to the user's operation. Since the noise component is a single-phase AC voltage of 100 V of 50 Hz or 60 Hz input to the power supply, the peak of the noise component is at 50 Hz or 60 Hz. The signal in this frequency band is attenuated by an analog filter included in the current detection circuit and a digital filter incorporated in the program of the microcontroller, but remains to some extent. As the filter, a band pass filter (band pass filter), a low pass filter (low pass filter), or the like is used. Here, the low-pass filter is a filter that passes a low frequency well and does not pass (attenuate) a band having a frequency higher than a certain cutoff frequency. In order to attenuate 50 Hz noise, it is necessary to set the cutoff frequency (cutoff frequency) of the low-pass filter to be lower than 50 Hz. Further, as the cut-off frequency is set lower than 50 Hz, the attenuation in the 50 Hz band increases. On the other hand, the signal change in the first unit time is obtained by integrating the signal change for each cycle T of the touch determination, and the noise component included in the signal change for each cycle of the touch determination is integrated (added). As a result, the noise components cancel each other and approach zero. Therefore, as the first unit time becomes longer, the noise component included in the signal change is greatly attenuated. Since the period is the reciprocal of the frequency, the first unit time is the reciprocal of the cutoff frequency of the low-pass filter, and the first unit time is preferably set to 20 msec or more.

  Next, the electronic apparatus of the present invention will be described. Hereinafter, the electronic apparatus of the present invention will be described using a monitor as an example. FIG. 3 shows a schematic perspective view of the electronic apparatus of the present invention. FIG. 4 is a schematic cross-sectional view of the electronic apparatus of the present invention taken along line IV-IV in FIG. FIG. 5 shows an equivalent circuit diagram of the touch sensor function in the electronic apparatus of the present invention. FIG. 6 shows a schematic block diagram of the current detection circuit and its peripheral functions. 4 to 6 correspond to diagrams in which the monitor of FIG. 3 is rotated 90 degrees clockwise.

  The electronic device 1 of the present invention includes the touch sensor device 100 of the present invention. The touch panel 101 includes an impedance surface 39 such as a transparent conductive layer, a plurality of electrodes 38 provided at four corners of the impedance surface 39, and a protective layer 37 that covers the surface of the impedance surface 39 on the insulating substrate 41. The AC voltage output from the oscillator is applied to the impedance surface via the plurality of electrodes 38. When the indicator 23 comes into contact (close proximity) with the surface of the touch panel 101, a capacitance 25 is formed between the indicator 23 and the impedance surface 39. The current detection unit of the touch sensor device 100 includes a plurality of current detection circuits 29a to 29d that respectively detect currents flowing through the plurality of electrodes. The sum of the currents flowing through the plurality of electrodes 38 is proportional to the capacitance 25 formed between the indicator 23 and the impedance surface 39. Outputs of the plurality of current detection circuits 29a to 29d are converted into numerical values by sampling (sampling) and discretization. Based on these numerical values, a signal proportional to the capacitance 25 (hereinafter referred to as “signal”) is calculated. The signal is output at a constant frequency of 30 to 120 Hz. The impedance surface referred to in this document includes a three-dimensional structure, for example, a transparent conductive layer that is not patterned in a region corresponding to the display portion.

  In the form shown in FIG. 4, the touch panel 101 is supported by bonding the upper surface of the outer periphery of the touch panel 101 and the inside of the housing 3 of the electronic device 1. Here, the material of the housing 3 can be plastic, for example. The plastic is made of a polymer compound, has plasticity, and is an insulator. An LCD 5 is provided as a display device below the touch panel 101. In FIG. 4, the touch panel 101 and the LCD 5 are separated from each other. However, an adhesive film may be used between the LCD 5 and the touch panel 101 to bond them together by laminating or the like. In that case, since an air layer does not enter between the LCD 5 and the touch panel 101, there is an advantage that the light transmittance from the LCD 5 to the touch panel 101 can be increased. Since the LCD 5 is thinner and lighter than other display devices such as a CRT (Cathode Ray Tube) or a PDP, it is suitable for mounting on an electronic device. The liquid crystal panel used for the LCD 5 has a structure in which liquid crystal is sealed between two glass plates, and an image is displayed by changing the direction of liquid crystal molecules by applying a voltage and increasing or decreasing light transmittance. In order to illuminate the liquid crystal, a backlight is provided on the back of the liquid crystal panel. The two glass substrates are generally composed of a TFT (Thin Film Transistor) substrate and a counter substrate. As described above, a transmissive LCD that modulates planar backlight light from the back surface with a liquid crystal panel and displays an image has been described as an example, but a metal electrode serving as a reflector is formed on the TFT substrate described above, A reflective LCD using ambient light for display may be used. Further, a transflective LCD that is used for both transmission and reflection may be obtained by making fine holes in a dot pattern on the reflection plate.

  As the touch panel 101, a touch panel in which a transparent conductive layer 39 is formed on an insulating substrate 41 by a sputtering method or the like can be used. Here, the material of the transparent conductive layer 39 can be, for example, ITO (Indium Tin Oxide). The thickness of the transparent conductive layer 39 can be 10 nm to 300 nm, and the sheet resistance can be 100Ω to 1000Ω. At the four corners of the transparent conductive layer 39, a flexible printed circuit board (hereinafter referred to as “FPC” (Flexible Printed Circuit)) is provided through a conductive adhesive material such as an anisotropic conductive film (ACF). 7 terminal portions (electrodes 38) are connected. Alternatively, electrodes made of metal may be formed at the four corners of the transparent conductive layer 39. The metal in this case is preferably a material having a low contact resistance with respect to ITO, such as silver or titanium. Alternatively, a metal wiring may be formed and the outer periphery of the transparent conductive layer 39 may be routed. In that case, the ITO under the wiring is patterned in order to insulate the wiring from the ITO.

  Further, a protective layer 37 that covers the transparent conductive layer 39 is formed. Glass, plastic, resin, or the like can be used for the protective layer 37. Here, the thickness of the protective layer 37 is preferably set between 0.1 mm and 2.0 mm. As the thickness of the protective layer 37 decreases, the capacitance 25 formed between the indicator 23 and the transparent conductive layer 39 in contact with each other increases, and the signal-to-noise ratio (S / N) of the touch sensor function is increased. Can be increased. On the other hand, the durability against repeated input by the indicator 23 can be increased as the thickness of the protective layer 37 is increased.

  In the form shown in FIG. 4, the FPC 7 is formed as a wiring for transmitting an electrical signal because the touch panel 101 and the main board 19 are separated from each other. Here, it is preferable to use the FPC 7 because there are places where it is necessary to bend the wiring and the substrate due to space restrictions. The FPC 7 is generally a printed circuit board that is flexible and can be greatly deformed. An adhesive layer is formed on a film-like insulating substrate having a thickness of 12 μm to 50 μm, and the thickness is further formed thereon. This is a structure in which a conductor foil of about 12 μm to 50 μm is formed. Portions other than the terminal portion and the solder portion of the FPC 7 are covered with an insulator and protected.

  The other terminal portion of the FPC 7 drawn out from the transparent conductive layer 39 via the electrode 38 is connected to the input side of the controller 21 for the touch sensor device 100 via a connector on the main substrate 19. The main board 19 is connected to an LCD module composed of a liquid crystal panel, a backlight, etc. via a connector (not shown). The power supply device 18 is connected to the main board 19 without using a connector. Between the power supply device 18 and the main board 19, wirings of a positive power supply voltage + 3V to + 15V, a negative power supply voltage −15V to −3V, and a reference voltage 0V can be connected.

  The main board 19 is composed of a surface mount board, a chip incorporating a microcontroller 58 and a flash memory, a display interface IC, a power supply control IC, a controller 21 for the touch sensor device 100, and main functions of the oscillation circuit IC. A chip that has Alternatively, the main board 19 may be mounted on a thin printed wiring board in which the controller 21 is provided on the FPC 7 or the like.

  In the form shown in FIG. 5, the controller 21 for the touch sensor device 100 includes four current detection circuits 29 a to 29 d and is electrically connected to each of the four corners of the transparent conductive layer 39 via electrodes 38. Yes. Further, the output terminal (AC voltage source 27) of the oscillation circuit IC is electrically connected to the four corners of the transparent conductive layer 39. Here, the AC voltage can be a sine wave voltage, the amplitude of which can be set between 0.5 V and 2 V, and the frequency thereof can be set between 20 kHz and 200 kHz.

  In the form shown in FIG. 6, the current detection circuit 29 c includes a current-voltage conversion circuit 28 c that is a front stage and an AC-DC conversion circuit 54 c that is a rear stage. The output terminal of the AC-DC conversion circuit 54 c is input to an analog-digital conversion circuit 56 built in the microcontroller 58. Here, the analog-digital conversion circuit 56 is capable of multi-channel input, and the four outputs of the AC-DC conversion circuits 54a to 54d are inputted.

  A CPU 60 (Central Processing Unit) is a central processing unit of the microcontroller 58, and is connected to the analog-digital conversion circuit 56, the flash memory 62, and the like. The flash memory 62 stores the program of the present invention for the touch sensor device 100. A non-volatile memory that can hold data even when the power is turned off, such as the flash memory 62, is used for storing the program.

  Next, the operation of the electronic apparatus 1 including the touch sensor device 100 according to the first embodiment will be described in detail mainly with reference to FIG.

  A sinusoidal voltage is applied from the AC voltage source 27 to the transparent conductive layer 39, and the transparent conductive layer 39 is maintained at a uniform voltage. When the indicator 23 comes into contact with the surface of the protective layer 37, a capacitance 25 of 5 pF to 50 pF is formed between the indicator 23 and the transparent conductive layer 39 via the protective layer 37. When the indicator 23 is a fingertip, the human body is conductive, and thus the capacitance 25 formed by the contact of the indicator 23 is connected to the potential of the human body. The human body has a grounding effect, and one end of the capacitance 25 is grounded.

  The current accompanying the touch is shunted as currents Ia to Id to the current detection circuits 29a to 29d via the transparent conductive layer 39, respectively. Currents Ia to Id are currents detected by the current detection circuits 29a to 29d shown in FIG. That is, the current Ia is the current detected by the current detection circuit 29a, the current Ib is the current detection circuit 29b, the current Ic is the current detection circuit 29c, and the current Id is the current detected by the current detection circuit 29d. The ratios of the currents Ia to Id change according to the resistances Ra to Rd of the transparent conductive layer 39, and the resistances Ra to Rd change according to the position of the indicator 23 in contact with the touch panel 101. An example of the calculation related to the touch position is as follows.

x = k1 + k2 · (Ib + Ic) / (Ia + Ib + Ic + Id) (Formula 1)
y = k1 + k2 · (Ia + Ib) / (Ia + Ib + Ic + Id) (Formula 2)
Here, x is the x coordinate of the touch position, and y is the y coordinate. k1 and k2 are constants.

  FIG. 7 shows an example of the voltage waveform of the operation in the touch sensor device 100 according to the first embodiment. In the example illustrated in FIG. 7, the touch detection period is 3 msec and the touch detection period is 40 Hz. Here, the period of the touch detection period may be set between 20 Hz and 120 Hz. At this time, although one cycle is 25 msec, the touch detection period is 3 msec, so the remaining 22 msec is set as a pause period.

  In FIG. 7, Vin is an output waveform of the AC voltage source 27, and Vout is an output waveform of the current-voltage conversion circuit 28 included in the current detection circuit 29. Here, the frequency of Vin is 100 kHz and the amplitude is 1V. At this time, when there is no touch, for example, the amplitude of Vout is 3V, and when there is a touch, the amplitude of Vout is 6V. That is, the amplitude increases by 3V with the touch. Here, the amplitude of Vout in the absence of the touch is 3 V. This is due to the influence of the parasitic capacitance (floating capacitance) seen from the transparent conductive layer 39 and the fact that Vin is included in Vout. . In this way, in practice, a certain amount of output is generated in the output of the analog-digital conversion circuit 56 even if the indicator 23 and a human body such as a palm are not approached.

  5 and 6, since the outputs of the current detection circuits 29a to 29d are AC voltages, the AC voltages are converted into DC voltages by the subsequent AC-DC conversion circuits 54a to 54d. Furthermore, since the DC voltage output of the AC-DC conversion circuits 54a to 54d is an analog signal, the analog signal is converted into a digital signal by the analog-digital conversion circuit 56 in the subsequent stage. Next, the CPU 60 performs numerical calculation based on the converted digital signal. By the signal processing of these current detection circuits 29 to CPU 60, each of the currents Ia to Id flowing in the current detection circuit 29 is a value (detection signal) proportional to the magnitude of the current in one cycle of determination of touch determination. Converted and numerically calculated.

  Based on each detection signal, the CPU 60 detects the presence of a touch, performs an operation related to the touch position, and executes a mouse event on the operating system. The mouse event includes movement of a pointer (mouse cursor) or selection (determination) of an item pointed to by the pointer. Here, selection of an item includes, for example, mouse click down by touch-on determination immediately after the indicator touches, maintenance of mouse click down while the indicator touches, and mouse click up by touch-off determination immediately after the indicator leaves. Become. The operation of these microcontrollers 58 is repeatedly executed after the electronic device 1 is powered on, and the CPU 60 reads out the program from the flash memory 62. In this way, the process from analog-digital conversion to mouse event is automatically operated by the microcontroller 58 at a predetermined period of 40 Hz.

  Next, the presence of parasitic capacitance (floating capacitance) viewed from the transparent conductive layer 39 will be described. The current detection circuits 29a to 29d are composed of an operational amplifier 50 and a resistance element 52, and the non-inverting input terminal of the operational amplifier 50 and the transparent conductive layer 39 are electrically connected. The non-inverting input terminal of the operational amplifier 50 and the transparent conductive layer 39 are connected via a wiring such as the FPC 7, but a parasitic capacitance 26 is formed between the wiring and the ground 35.

  As a countermeasure, it is preferable to perform baseline correction by holding a signal associated with the parasitic capacitance 26 as a baseline and subtracting it from a newly acquired signal. Here, the outputs of the analog-digital conversion circuit 56 corresponding to the current detection circuits 29a to 29d are denoted as detection signal a to detection signal d. Further, the detection signal a to detection signal d acquired when the touch sensor device 100 determines that the indicator 23 and a human body such as a palm are not approaching are denoted as a baseline a to a baseline d. As shown in Equation 3, the sum of the detection signals a to d is defined as a detection signal value h (iT). As shown in Expression 4, the sum of the base line a to the base line d is defined as a base line BL. The baseline BL is stored in the reference storage mechanism 104. As shown in Expression 5, the reference calculation mechanism 103 sets a value obtained by subtracting the base line BL from the detection signal value h (iT) as a signal output value f (iT).

Detection signal value h (iT) = detection signal a + detection signal b + detection signal c + detection signal d (Equation 3)
Baseline BL = Baseline a + Baseline b + Baseline c + Baseline d (Formula 4)
Signal output value f (iT) = detection signal value h (iT) −baseline BL (Formula 5)

  In the present embodiment, when the signal rises after the touch-on determination, the touch-off determination threshold (first threshold) corresponding to the touch-on determination is updated. On the other hand, when the signal is constant or falls, the first threshold value is not updated. Next, the signal is compared with the first threshold value, and when the signal is smaller than the first threshold value, the touch-off determination is performed. When the indicator is detached, the signal tends to monotonously decrease with time. If the first threshold value is not updated while the signal is decreasing, if the indicator completely leaves the touch panel surface, the signal is greatly decreased. Therefore, when the signal becomes smaller than the first threshold value, the touch-off is performed. Determined. On the other hand, when the indicator touches the surface of the touch panel and performs a drag operation, the signal tends to repeatedly increase and decrease. In the period in which the signal increases, the first threshold is calculated and updated based on the acquired signal. In this way, when the signal generally decreases while the signal repeatedly increases and decreases, the first threshold value can be adjusted to be low, so that erroneous touch-off determination can be prevented in the drag operation. Therefore, when the indicator is in contact with the surface of the touch panel, the touch-off determination can be prevented while the touch-off determination can be reliably performed when the indicator is detached.

  Next, a touch sensor device according to a second embodiment will be described. FIG. 8 shows a flowchart for explaining the operation and control method of the touch sensor device and the program for operating the touch sensor device according to the second embodiment of the present invention. Hereinafter, the same reference numerals as those in the first embodiment are used for the configuration substantially the same as that in the first embodiment, and portions different from the first embodiment will be mainly described. In the first embodiment, a common threshold value (first threshold value) is used for the touch-off determination and the touch-on determination. In the second embodiment, different threshold values are used for the touch-on determination and the touch-off determination. Here, the threshold used for touch-off determination is a first threshold Th1, and the threshold used for touch-on determination is a second threshold Th2.

  In the first embodiment, the first threshold Th1 is appropriately updated based on the signal in contact. In this case, the first threshold value Th1 calculated based on the previous contact signal may be an inappropriate value for the current touch-on determination according to the difference between the previous contact signal and the current contact signal. There is. Specifically, the output value of the signal during contact may be very high. When the signal during the previous contact is very high, the first threshold Th1 is also very high, so that it is difficult to make a touch-on determination in the current touch determination. On the other hand, when the signal during the previous contact is very low, the first threshold value Th1 is also very low. Therefore, in the current touch determination, even if the fingertip is not touching, the palm is only approached and erroneously determined to be on. May end up.

  Therefore, in the second embodiment, the first threshold Th1 used for touch-off determination is updated in the same manner as in the first embodiment, but the second threshold Th2 used for touch-on determination is not updated. That is, the second threshold is a constant (fixed type). The second threshold Th2 is set to a sufficiently high value relative to the output values of these signals by measuring in advance signals associated with holding the palm of the surface of the touch panel or signals associated with the stray finger. For example, the second threshold Th2 is set 3 pF to 5 pF higher than the output value of the signal in the state where the palm is held up. In signal measurement associated with holding the palm of the surface of the touch panel, the distance between the touch panel and the palm is preferably set between 5 mm and 50 mm. This is because the shortest accessible distance is about 5 mm without contact between the surface of the touch panel and the palm, and the distance between the palm in the stray finger and the surface of the touch panel is 30 to 50 mm. The second threshold Th2 is stored in the threshold storage mechanism 109 together with the first threshold Th1. With regard to the touch-on determination, even if the fingertip touches and the touch panel does not react (mouse event), the user is conscious of trying again. Next time, try to contact more deeply. Here, “deeply” means to increase the contact area between the surface of the touch panel and the fingertip. This is based on the idea that touch-on determination is not essential in cases such as when the fingertip is touched shallowly.

  In the form shown in FIG. 8, the touch-on determination is made in S203 by comparing the output value f [iT] of the signal with the second threshold Th2. Other than this, the configuration is the same as that shown in FIG.

  According to the present embodiment, the touch-on misjudgment can be suppressed by setting the threshold value of the touch-on determination (second threshold Th2) as a constant and making the value of the second threshold Th2 sufficiently higher than a signal accompanying a stray finger or the like. effective.

  A touch sensor device according to a third embodiment of the present invention will be described. FIG. 9 shows a schematic block diagram of a touch sensor device according to a third embodiment of the present invention. In the third embodiment, in addition to the comparison between the output value of the signal and the threshold value, the magnitude of the change of the signal in a predetermined unit time (second unit time) (hereinafter, “first difference value of the signal”) is also touch-determined. Used for indicators.

  The touch sensor device 300 according to the third embodiment further includes a difference calculation mechanism 311 in addition to the configuration of the first embodiment. The difference calculation mechanism 311 calculates a first difference value of the signal per predetermined time from the output value of the signal calculated by the signal calculation mechanism 305 and the output value of the signal stored in the signal storage mechanism 307.

  Next, an operation and control method of the touch sensor device 300 and a program for operating the touch sensor device 300 will be described. FIG. 10 shows a flowchart for explaining the operation and control method of the touch sensor device and the program for operating the touch sensor device according to the third embodiment of the present invention.

  First, after the operation is started (S300), the contact determination mechanism 310 determines the touch-off as in the first embodiment (S301). Next, the signal acquisition mechanism 302 acquires a signal in the determination of the i-th touch determination. The signal calculation mechanism 305 calculates the output value f [iT] of the signal as in the first embodiment.

  Next, the difference calculation mechanism 311 calculates the first difference value gj [iT] of the signal in the second unit time jT (S303). The first difference value gj [iT] of the signal is calculated by f [iT] −f [(i−j) T] (step A03). In the form shown in FIG. 10, the coefficient j that determines the second unit time is set to 2. For example, when T is 25 msec, the second unit time is 50 msec. The signal output value f [(i−2) T] is signal data acquired in the (i−2) th loop and held in the signal storage mechanism 307. However, when i is 3 or less, f [(i−2) T] is set to f [1T].

  Next, the contact determination mechanism 310 compares the first difference value g2 [iT] calculated by the difference calculation mechanism 311 with the third threshold value Th3 set in the threshold value storage mechanism 309 (S304). When the first difference value g2 [iT] is larger than the third threshold Th3, i is counted up by one (S305), and then the contact determination mechanism 310 determines touch-on (S308).

  In S304, when the first difference value g2 [iT] is equal to or smaller than the third threshold Th3, the contact determination mechanism determines the signal output value f [iT] and the first value in the same manner as in the first embodiment or the second embodiment. The first threshold value Th1 or the second threshold value Th2 is compared (S306). In the form shown in FIG. 10, the second threshold Th2 that is a constant is used as in the second embodiment. When the output value f [iT] of the signal is larger than the second threshold Th2, i is counted up by one (S305), and then the contact determination mechanism 310 determines touch-on (S308). On the other hand, if the signal output value f [iT] is less than or equal to the second threshold Th2 in S306, i is counted up by one (S307), and the process returns to S302. In this case, the contact determination mechanism 310 does not determine touch-on.

  Next, after the touch-on determination (S308), in the determination of the i-th touch determination, the signal calculation mechanism 305 calculates the output value f [iT] of the signal (S309).

Next, the signal comparison mechanism 306 outputs the output value f of the i-th signal as in the first embodiment.
[IT] is compared with the output value f [(iq) T] of the (iq) -th signal (S310). In the embodiment shown in FIG. 10, q = 3. When the output value f [iT] of the i-th signal is equal to or less than the output value f [(i-3) T] of the i-3th signal, the difference calculation mechanism 311 performs the first difference value similarly to S303. g2 [iT] = f [iT] −f [(i−2) T] is calculated (S314). Next, the contact determination mechanism 310 compares the first difference value g2 [iT] with a negative third threshold value -Th3 (S315). When the first difference value g2 [iT] is smaller than the negative third threshold value -Th3, i is counted up by one (S316), and then the contact determination mechanism 310 determines the touch-off (S310). On the other hand, in S315, when the first difference value g2 [iT] is greater than or equal to the negative third threshold −Th3, the contact determination mechanism 310 compares the signal output value f [iT] with the first threshold Th1 ( S317). When the output value f [iT] of the signal is smaller than the first threshold Th1, i is counted up by one (S316), and then the contact determination mechanism 310 determines touch-off (S301). If the signal output value f [iT] is equal to or greater than the first threshold Th1 in S317, i is incremented by one (S318), and the process returns to S309. In this case, the contact determination mechanism 310 does not determine touch-off.

  In S304 and S306, and S315 and S317, the comparison between the first difference value and the third threshold value and the comparison between the output value of the signal and the first threshold value are used for touch determination. When the contact of the indicator and the release of the indicator are slow, the difference value per unit time is small and the touch determination cannot be made in S304 and S315, but by using the output value of the signal in S306 and S317, The touch determination can be surely made. For example, even if the fingertip is removed, if a touch-off determination is not made, mouse click down (pointer selection) is maintained. Since the coordinate position of the pointer is calculated based on a signal unrelated to the contact of the pointer, the coordinate position becomes a random value, and the pointer is selected and determined at a coordinate position different from the user's intention. This phenomenon is a malfunction, and it becomes a very serious state in which the touch sensor device cannot automatically return to the original normal state.

  In the above embodiment, for example, in S304 and S315, positive and negative are considered, but the difference value and the threshold value may be compared with an absolute value.

  The absolute value of the third threshold Th3 is preferably set to 1 pF to 3 pF. Within this range, even when a bare hand or a glove is worn, touch determination can be made when the fingertip touches the touch panel or the contact with the touch panel is released.

  The second unit time is preferably set to 8 msec to 100 msec. By setting the second unit time in consideration of the time required for the signal change, it is possible to greatly reduce the influence due to the approach of the palm in the touch determination. In addition, the effect caused by a stray finger that stops the palm while keeping the palm close can be greatly reduced. This is because the movement of the palm approaching the surface of the touch panel and moving the palm horizontally is also very slow compared to the fingertip contact operation.

  In the above embodiment, the difference value is used for both the touch-on determination and the touch-off determination, but the difference value may be used for only one of the determinations. Moreover, in the said form, although the 3rd threshold value was used as a threshold value common to touch-on determination and touch-off determination, you may set a 3rd threshold value to a different value by touch-on determination and touch-off determination.

  The other form of 3rd Embodiment is the same as that of 1st Embodiment. In the above description, the combination with the second embodiment has been described as an example. However, the third embodiment can be combined with the first embodiment that does not use the second threshold.

  According to the third embodiment, even when the user is wearing gloves or when the cover glass (protective layer) of the touch panel 301 is thick, the touch determination can be made appropriately. Moreover, durability of a touch sensor apparatus can be improved by thickening a cover glass. In particular, there is a possibility that the touch-off determination at the time of wearing the glove may be mistaken only by the touch determination using the difference value, but when the glove is worn by combining the touch determination using the difference value with the touch-off determination of the first embodiment. It is also possible to make a touch-off determination with certainty.

  In the touch sensor device according to the first to third embodiments, after the touch-on determination is performed, the signal output value is decreased at a certain rate to perform the touch-off determination, and the signal output value is periodically increased or decreased. The first threshold value Th1 at the time of touch-off determination differs depending on whether the touch-off determination is made by reducing the entire screen. That is, the first threshold Th1 can be lowered by periodically increasing or decreasing the output value of the signal.

  From the viewpoint of the distance between the indicator and the touch panel, the signal output value is decreased at a constant rate when the signal output value is periodically increased or decreased, and the touch-off determination is performed by reducing the overall value. The distance between the indicator and the touch panel at the time of touch-off can be increased as compared with the case of making the touch-off determination.

  Here, when the output value of the signal is periodically increased or decreased, it is preferable that the frequency of the cycle in which the signal decreases once and increases once is 2.5 Hz or less. Since the first unit time, which is a unit time for determining whether or not the signal is increasing, is preferably 200 msec or less, in order to sample the signal increase / decrease as a sine wave, the signal increase / decrease period needs to be 400 msec or more. It is. In one cycle, the magnitude of the decrease in the output value of the signal is set to be larger than the magnitude of the increase in the output value of the signal, and the absolute value of the magnitude of the decrease is 1 pF than the absolute value of the magnitude of the increase. It is set to be 3 pF or less. Further, when the signal output value becomes smaller than the first threshold value Th1 due to the signal decrease in the first period, the distance L for the touch-off determination is not sufficiently long. Therefore, the signal decrease amount is set so that the signal output value does not become smaller than the first threshold Th1 due to the signal decrease in the first period. On the other hand, when the output value of the signal is decreased at a constant rate, it is decreased by 0.12 pF per second. The first threshold Th1 is updated by the current signal output value c × sensitivity α (= 0.6).

  In this way, by repeatedly raising and lowering the indicator and releasing the indicator from the surface of the touch panel, it is possible to reproduce the signal transition during the drag operation and confirm the effect of the first threshold update in the touch sensor device. .

  The electronic device of the present invention includes the touch sensor device of the present invention. Examples of the electronic device of the present invention include a game machine, a portable information terminal, a PDA, a car navigation system, a notebook computer, a portable DVD player, a TV / game machine attached to a passenger seat of an airplane or a bus, a factory automation (FA) device, and the like. Can be mentioned.

  The program of the present invention can cause the touch sensor device to realize the above functions and procedures.

  Next, an electronic apparatus according to a fourth embodiment of the invention will be described. FIG. 11 shows a schematic exploded perspective view of an electronic apparatus of the present invention provided with the touch sensor device of the present invention. FIG. 12 is a schematic plan view of the electronic device shown in FIG. 11 and 12 exemplarily illustrate an LCD as an electronic device. In FIG. 12, the counter substrate is not shown. Note that FIGS. 11 and 12 are hatched so as to be easily visible even in a portion that is not a cross section. 11 and 12, the same elements as those in the above embodiment are denoted by the same reference numerals.

  An electronic apparatus 401 according to the fourth embodiment includes the touch sensor device 400 of the present invention. The electronic device 401 includes a counter electrode 412, a pixel electrode 405, wirings 404, 406, and 408, and a liquid crystal 402 interposed between the counter electrode 412 and the wirings 404, 406, and 408. The counter electrode 412 is also used as an impedance surface. In the electronic device 401, at least a part of the wirings 404, 406, and 408 is electrically suspended, or at least a part of the wirings 404, 406, and 408 is electrically suspended and then applied to the impedance surface. Further, switch portions 416, 417, 418, and 421 for applying a voltage to at least a part of the wirings 404, 406, and 408 are provided. The LCD 401 has a three-layer structure including a counter electrode 412, a liquid crystal 402, and a pixel electrode 405. The counter electrode 412 is also used as an impedance surface, and an AC voltage applied to the impedance surface is simultaneously applied to the storage capacitor line 408 or Further, switch portions 416, 417, 418, and 421 for electrically floating the scanning line 406 are provided.

  Based on the current detected by the current detection circuit 29, the output value and difference value of the signal are calculated and used for touch-on determination and touch-off determination. The matters relating to the touch-on determination and the touch-off determination are the same as those in the first to third embodiments, and a description thereof is omitted here.

  In the first embodiment, the touch sensor device is manufactured as a separate body from the display device. On the other hand, in the fourth embodiment, the surface capacitive coupling type touch sensor device 400 is built in using the LCD 401 as the display device. For example, a transparent conductive layer used for the counter electrode 412 of the LCD 401 is used as the impedance surface. Thereby, the manufacturing process of the touch sensor device 400 and the electronic device 401 can be simplified, and the manufacturing cost can be reduced. Furthermore, since a dedicated substrate for the touch sensor device 400 is not required, the weight and thickness are reduced. And the effect that the transmittance | permeability of light is high and the image quality of a display apparatus improves is also acquired.

  However, since the counter electrode 412 is close to the TFT substrate 410 via the liquid crystal element 402, a very large capacitance such as the liquid crystal element 402 exists. Therefore, a potential difference is generated between the counter electrode 412 and the TFT substrate 410 due to the potential of the electrodes and wirings (storage capacitor line 408, signal line 404, scanning line 406, etc.) on the TFT substrate 410. Therefore, the counter electrode 412 that also serves as an impedance surface is affected by an extremely large parasitic capacitance. As a result, since the S / N of the touch sensor function is reduced, it becomes difficult to detect the touch position accurately by sensing the presence of the touch.

  Therefore, in the fourth embodiment, the display period and the position detection period are divided in time. In the position detection period, the display region 403 is set to a high impedance with respect to the outside, and is electrically floated. Alternatively, in the position detection period, the same voltage as that of the counter electrode 412 is applied to the electrode and the wiring on the TFT substrate 410. As a result, the display region 403 is held at the same potential as the counter electrode 412 due to capacitive coupling between the display region 403 and the counter electrode 412. For this reason, since the potential of the display region 403 follows the same potential as that of the counter electrode 412, the influence of parasitic capacitance on the counter electrode 412 can be extremely reduced.

  Details of the electronic apparatus 401 according to the fourth embodiment will be described. In the fourth embodiment, a switch element is provided on a wiring for transmitting an electric signal from the outside of the display area to the inside of the display area. Specifically, in order to transmit an electric signal from the second circuit portion (scanning line driver circuit 414, signal line driver circuit 415, etc.) outside the display region 403 to the first circuit portion (TFT 411, etc.) inside the display region 403. A first high impedance switch unit 416, a second high impedance switch unit 417, and a third high impedance switch unit 418 are provided on the wiring portion.

  Here, the second circuit portion outside the display region 403 may be formed on the same substrate as the first circuit portion inside the display region 403 or may be on the external substrate. When the second circuit portion outside the display region 403 is provided on the same substrate as the first circuit portion inside the display region 403, the high impedance switch portion 416 is provided on the wiring portion connecting the outside of the display region 403 and the external substrate. , 417, 418 are preferably provided. Specifically, the wiring portion in which the high impedance switch portions 416, 417, and 418 are provided is preferably at least one of a signal line 404, a scanning line 406, a storage capacitor line 408, and a power supply line (not shown). .

  Moreover, it is preferable to provide a switching control circuit for controlling the high impedance switch units 416, 417, and 418. The switching control circuit preferably controls at least one of the wiring portions for transmitting an electric signal from the outside of the display area 403 to the inside of the display area 403 to a high impedance during the period in which the current detection circuit 29 detects the current. .

  Here, the “impedance control mechanism” can be configured by the high impedance switch units 416, 417, and 418 and the switching control circuit. This “impedance control mechanism” may be formed on the TFT substrate 410 or may be formed on a separate control circuit substrate.

  This “impedance control mechanism” is configured to electrically connect the first circuit portion in the display region 403 of the TFT substrate 410 to the second circuit portion outside the display region 403 during the detection period for detecting the contact position. It can be. In addition, the “impedance control mechanism” includes high impedance switch units 416, 417, and 418 formed on a wiring unit that connects the first circuit unit and the second circuit unit, and high impedance switch units 416, 417, and 418. A switching control circuit that performs on / off control.

  Next, operations of the high impedance switch units 416, 417, and 418 will be described. In order to provide an electrically high impedance between the first circuit portion inside the display region 403 (in the pixel matrix portion) and the second circuit portion at the outer peripheral portion of the display region 403, the outer peripheral portion of the display region 403 is It has the following structure. A first high impedance switch unit 416 is provided for each signal path of the scanning line 406, and a second high impedance switch unit 417 is provided for each signal path of the signal line 404. A third high impedance switch unit 418 is provided for each path. The high impedance switch units 416, 417, and 418 are switching-controlled by a switching control circuit. Thereby, the scanning line 406 and the signal line 404 for transmitting an electric signal from the outside to the inside of the display region 403 can be set to high impedance.

  The position detection period uses a vertical blanking period. In the position detection period, the high impedance switch units 416, 417, and 418 are all turned off as shown in FIG. At this time, the signal line 404, the scanning line 406, and the storage capacitor line 408 are connected to wiring outside the display region 403 (wiring connected to the scanning line driving circuit 414, the signal line driving circuit 415, and the common electrode COM). , High impedance.

  In the position detection period, the COM-current detection circuit changeover switch unit 421 is in a conductive state with respect to the AC voltage source 27 side including the current detection circuit 29. In the state of the switch shown in FIG. 12, an in-phase AC voltage generated by the AC voltage source 27 is applied to the electrodes 430 a to 430 d near the four corners of the TFT substrate 410. Since the electrodes 430 a to 430 d are electrically connected to the counter electrode 412 via the anisotropic conductor 434, an alternating voltage is applied near the four corners of the counter electrode 412.

  FIG. 13 is a timing chart showing voltages at various parts of the electronic device 401 according to the fourth embodiment. The voltage of the counter electrode 412 is Vc, the voltage of the signal line 404 is Vd, the voltage of the scanning line 406 is Vg, and the voltage of the pixel electrode 405 is Vs. The difference between the voltage Vg of the scanning line 406 and the voltage Vs of the pixel electrode 405 is indicated by Vgs. The counter electrode 412, the signal line 404, the scanning line 406, and the pixel electrode 405 are electrically connected to the common electrode COM or the current detection circuit 29 via a wiring. For switching the common electrode COM or the current detection circuit 29, a COM-current detection circuit changeover switch unit 421 is used.

  In addition, a position detection period is provided after the display driving period. Note that, although an example of each voltage is shown in the drawing, the voltage Vd of the signal line 404 differs depending on the signal to be written, and therefore no numerical value is entered. Referring to the voltage timing chart of FIG. 13, during the position detection period, each scanning line 406 has high impedance and is capacitively coupled to the counter electrode 412. Therefore, the voltage Vg of the scanning line 406 varies with the same amplitude as that of the counter electrode 412.

As described above, according to the fourth embodiment, a circuit (pixel electrode 405 or the like) inside the pixel matrix is high with respect to an external circuit during the position detection period while achieving the same operational effects as the first embodiment. Since the impedance is set, the parasitic capacitance viewed from the counter electrode 412 becomes extremely small when an AC voltage is applied to the counter electrode 412. Specifically, in the background art (configuration in which the display area is not electrically floating), the parasitic capacitance is, for example, 15 nF, whereas in the fourth embodiment, the parasitic capacitance is reduced to, for example, 100 pF. As a result, the S / N ratio of the signal output from the current detection circuit 29 is, for example, 4 × 10 ⁻⁴ in the background art, but in the fourth embodiment, for example, 6 × 10 ⁻² and 140 times. Become.

  In addition, during the position detection period, the gate voltage and the source voltage of the TFT 410 both change with the same amplitude as the voltage amplitude of the counter electrode 412, so that the relative difference between the gate voltage and the source voltage is constant, and the transistor Vgs does not vary. As a result, it is possible to obtain a special effect such as minimizing the influence on image quality degradation due to driving in the position detection period.

  Here, n-channel TFTs are used as the high-impedance switch portions 416, 417, and 418 that electrically set the inside and outside of the display region 403 to high impedance. However, the high-impedance switch section may be a p-channel TFT or a transfer gate that combines an n-channel type and a p-channel type.

  In this way, the manufacturing process of the touch sensor device 400 and the electronic device 401 can be simplified and the manufacturing cost can be reduced. Furthermore, since a dedicated substrate for the touch sensor device 400 is not required, it is lightweight and thin. In addition, there is an effect that the light transmittance is high and the image quality of the display device is good.

Between the counter electrode 412 which is an impedance surface for touch detection and the indicator 23, there are an insulating substrate 41 and a deflecting plate. The thickness of the insulating substrate 41 can be set to 0.2 mm to 1.0 mm, for example. The thickness of the deflection plate can be, for example, 0.1 mm to 0.3 mm. In this case, the distance between the indicator 23 and the counter electrode 412 becomes long. For this reason, compared with the type in which the touch sensor device and the display device are assembled and attached externally, in the electronic device 401 of the present embodiment, the capacitance formed by the indicator 23 and the counter electrode 412 is reduced, In connection with this, the influence of the signal accompanying approach of a palm etc. is large, and accurate touch determination may become difficult. Therefore, with the configuration described in the first to third embodiments, the influence of the approach of the palm is reduced, and the signal change accompanying the contact of the indicator is captured, but when the indicator is detached, the touch is surely performed. There is an effect that it is determined. Other configurations, operations, and effects are the same as those in the first to third embodiments.

  Next, a touch sensor device according to a fifth embodiment of the invention will be described. Here, illustration of the configuration substantially the same as that of the fourth embodiment is omitted, and only the parts different from the fourth embodiment will be described. FIG. 14 is a schematic plan view showing a counter substrate of an electronic apparatus according to the fifth embodiment incorporating the touch sensor device of the present invention. FIG. 15 is a schematic sectional view taken along line XV-XV in FIG. In FIG. 14, even a portion that is not a cross section is hatched for easy visual recognition. 14 and 15, the same elements as those in the above embodiment are denoted by the same reference numerals.

  The electronic apparatus according to the fifth embodiment includes a switch unit (see the fourth embodiment) that simultaneously applies an AC voltage applied to the impedance surface 501 to the counter electrode 412 and the storage capacitor line (see the fourth embodiment). That is, the counter substrate 119 is different from the fourth embodiment.

  In the fourth embodiment, the counter electrode 412 of the LCD, which is an electronic device, is used as a touch sensor during the position detection period, and the display area is electrically set to high impedance with respect to the outside of the display area. As a result, although the parasitic capacitance of the counter electrode 412 is reduced, the parasitic capacitance viewed from the counter electrode 412 is still much larger than the capacitance accompanying touch.

  On the other hand, referring to FIG. 15, in the fifth embodiment, the position detection conductive layer 501 made of a transparent conductive layer is formed on the insulating substrate 41 on which the counter electrode 412 is formed on the lower side. . This position detection conductive layer 501 is used as a part of the touch panel. Further, an insulating protective layer 37 is formed on the position detection conductive layer 501. Here, a polarizing plate may be used as the protective layer 37. This is because the polarizing plate is necessary for displaying the LCD, and a process for forming the protective layer 37 for the touch sensor device is not necessary.

  Referring to FIG. 14, electrodes 430a to 430d are formed at the four corners of the position detection conductive layer 501, and current detection circuits 29a to 29d are electrically connected to the electrodes 430a to 430d, respectively. Further, the AC voltage source 27 is electrically connected through the current detection circuits 29a to 29d.

  Here, as compared with the transparent conductive layer of the counter electrode 412 of the fourth embodiment, the position detection conductive layer 501 is far from the TFT substrate and close to the surface of the touch sensor device (contact surface of the indicator). . Therefore, compared with the counter electrode 412, the parasitic capacitance seen from the position detection conductive layer 501 is small, and the capacitance accompanying the contact of the indicator is large. As a result, the S / N of the touch sensor device is improved.

  However, there is a problem that the parasitic capacitance viewed from the position detection conductive layer 501 is larger than the capacitance accompanying the contact of the indicator. In particular, fluctuations associated with the display contents of the LCD are a problem. This is due to the dielectric anisotropy of the liquid crystal molecules, and the problem arises based on the principle that the orientation changes depending on the display content and acts on the parasitic capacitance of the position detection conductive layer 501. As a result, the signal processing circuit has a problem that it is difficult to detect the presence or absence of a touch. That is, it is difficult for the signal processing circuit to distinguish whether the signal has changed due to the touch of the fingertip or whether the signal has changed since the display content has changed.

  FIG. 16 is a timing chart showing the voltages of the electrodes of the electronic device in the fifth embodiment. The voltage of the position detection conductive layer 501 is indicated by Va in FIG. Other voltages are assigned the same symbols as in the fourth embodiment, and the same voltages are applied. Va is a voltage of the AC voltage source 27, and a voltage having the same phase and amplitude as Va is also applied to the voltage Vc of the counter electrode 412. As a result, the counter electrode 412 functions as an ideal shield layer for the position detection conductive layer 501, and the counter electrode 412 is generated by a dielectric constant variation of a dielectric existing between the counter electrode 412 and the TFT substrate. As a result, the TFT substrate is less susceptible to fluctuations in the capacitance of the TFT substrate.

  As a result, the parasitic capacitance of the position detection conductive layer 501 (more accurately, a signal detected as a parasitic capacitance) is significantly reduced. In addition, the capacitance formed by the finger of the human body and the position detection conductive layer 501 can be reduced in the variation of the capacitance due to the display content of the LCD, and the presence or absence of touch can be accurately detected. There is. Other configurations, operations, and effects are the same as those in the first to fourth embodiments.

  A touch sensor device according to a sixth embodiment of the present invention will be described. FIG. 17 shows a schematic block diagram of a touch sensor device according to a sixth embodiment of the present invention. In the third embodiment, the magnitude of the change in signal per predetermined unit time (second unit time) (the first difference value of the signal) is compared with the third threshold Th3 to determine whether or not the touch is on. However, the second unit time was a fixed value determined by the initial setting. In the sixth embodiment, the second unit time is automatically adjusted according to the situation for each touch. Further, the position of the indicator is calculated in consideration of the influence accompanying the approach of the palm using the extrapolated value.

  In addition to the configuration of the third embodiment, the touch sensor device 600 according to the sixth embodiment further calculates a change determination mechanism 613 that determines the magnitude of a change in the output value of the signal per unit time, and an extrapolated value. An extrapolation calculation mechanism 614 and an extrapolation storage mechanism 615 that stores extrapolation values used for contact determination and calculation of the position of the indicator are provided. Although not described in the above embodiment, in FIG. 17, a difference storage mechanism 612 that stores the difference value and a position calculation mechanism 616 that calculates the position of the indicator are illustrated for the purpose of describing the present embodiment. Is shown. The difference storage mechanism 612 and the position calculation mechanism 616 are not elements included only in this embodiment.

  FIG. 18 shows a flowchart for explaining the operation and control method of the touch sensor device and the program for operating the touch sensor device according to the sixth embodiment of the present invention. In the sixth embodiment, one of the output values of the channel signal acquired at the four corners of the panel is fch [iT]. The contact position of the indicator is calculated based on the output value fch [iT] of each channel signal. The sum of the output values fch [iT] of the four channel signals is set as the signal output value f [iT], and touch-on determination is performed based on the signal output value f [iT]. In the description of each step of the flowchart, the total value f [iT] of the four channel signals is used as much as possible, and the output value fch [iT] of the signal of each channel is used only for the steps related to position calculation. In FIG. 40, the measurement result in Example 8 based on this embodiment is shown. 40 corresponds to the following description.

  First, after the initial setting, the contact determination mechanism 610 performs a touch-off determination as in the first embodiment (S601). Next, in the determination of the i-th touch determination, the signal acquisition mechanism 602 acquires a signal. The signal calculation mechanism 605 calculates the output value f [iT] of the signal as in the first embodiment (S602).

  Next, the difference calculation mechanism 611 calculates the second difference value g1 [iT] of the signal per third unit time (S603). Here, the second difference value g1 [iT] of the signal is calculated by g1 [iT] = f [iT] −f [(i−1) T]. The third unit time is a section for determining whether or not f [iT] is slowly changing. For example, the third unit time can be set to 16 milliseconds (= 1T = 1 * 16 milliseconds).

  Next, the change determination mechanism 613 compares the second difference value g1 [iT] with the fourth threshold value Th4 (S604). Here, the fourth threshold value Th4 is a threshold value for determining whether or not f [iT] changes gently, that is, whether or not the signal changes as the palm approaches, and is stored in the threshold value storage mechanism 609 in advance. Let me. The fourth threshold Th4 is a value obtained by dividing the third threshold Th3 by max (nm) (Th4 = Th3 / max (nm)). The third threshold Th3 is a threshold for determining touch-on as in the third embodiment. m is i for determining a sudden rise in f [iT] due to contact between the indicator and the touch sensor, and n is i for which touch-on determination is made. At this time, the second unit time for determining whether or not the touch-on determination is made is (n−m) T. max (n−m) is an upper limit value of (n−m), and an upper limit value of (n−m) T is set to max {(n−m) T}. For example, when T = 16 milliseconds and max (n−m) = 5 is set, max {(n−m) T} = 5 * 16 milliseconds = 80 milliseconds. When the third threshold Th3 is set to 1.5 pF, the fourth threshold Th4 is 0.3 pF (= Th3 / max (nm) = 1.5 pF / 5).

  If the second difference value g1 [iT] is equal to or smaller than the fourth threshold value Th4 in S604, i is incremented by 1 in S605, and the process returns to S602. On the other hand, when the second difference value g1 [iT] is larger than the fourth threshold Th4, i is substituted for m, and the first change point at which f [iT] starts to rise rapidly is 1T before mT (m−1). ) It is assumed that f [(m−1) T] in T (S606).

  Next, i is incremented by 1 (S607), the signal acquisition mechanism 602 acquires a signal in the same manner as S602, and the signal calculation mechanism 605 calculates the output value f [iT] of the signal (S608).

  Next, similarly to S603, the difference calculation mechanism 611 calculates the second difference value g1 [iT] of the signal per third unit time (S609). The difference storage mechanism 612 stores the second difference value g1 [iT].

  Next, the change determination mechanism 613 compares the second difference value g1 [iT] with the fourth threshold Th4 (S610). Here, if the second difference value g1 [iT] is equal to or greater than the fourth threshold Th4, i is counted up by one (S611), and the process returns to S608. On the other hand, when the second difference value g1 [iT] is smaller than the fourth threshold Th4, the extrapolation calculation mechanism 614 does not change the first value even after the output value f [iT] of the signal rapidly rises past the first change point. An extrapolated value to be extrapolated from the first change point to time iT is obtained based on a gradual upward trend before the change point (S612). Here, based on the second unit time (i−m + 1) T and the output value f [(m−1) T] of the signal at the first change point, the extrapolated value e [iT] is 2 * f [ (M-1) T]]-f [(2m-i-2) T]. The extrapolation storage mechanism 615 stores the extrapolation value e [iT].

  An equation of extrapolation value e [iT] = “2 * f [(m−1) T] −f [(2m−i−2) T” will be described with reference to FIG. The difference between the time iT and the time (m−1) T of the first change point is (i−m + 1) T. The time from time (m−1) T to (i−m + 1) T is (2m−i−2) T, and the signal at this time is f [(2m−i−2) T]. Since the time of the first change point is (m−1) T, the signal of the first change point is f [(m−1) T]. When the signal at time (m-1) T is subtracted from the signal before (im-1) T from time (m-1) T, f [(m-1) T] -f [(2m-i-2 ) T]. When this subtraction value and f [(m−1) T] of the first change point are added, the extrapolated value e [iT] is “2 * f [(m−1) T] −f [(2m−i). -2) T] ".

  The extrapolated value e [iT] is increased from the first change point to the time iT based on the tendency of a gradual increase before the first change point even if fch [iT] rapidly increases past the first change point. It can be obtained by inserting. The purpose of calculating extrapolation is that not only fingers but also palms approach the panel surface while the signal sharply rises due to the contact between the fingertip and the panel surface. This is because the signal accompanying the approach of the palm can be estimated more accurately by expecting an increase of the palm.

  Next, the difference calculation mechanism 603 calculates the difference between the output value f [iT] of the signal and the extrapolated value e [iT]. Next, the contact determination mechanism 610 compares the difference with the third threshold Th3 (S613). When the difference (f [iT] −e [iT]) is equal to or smaller than the third threshold Th3, i is counted up by 1 (S614), and the process returns to S602. This is equivalent to starting the touch-on determination from the beginning because the touch-on determination threshold is not reached. On the other hand, when the difference (f [iT] −e [iT]) is greater than the third threshold Th3, i is substituted for n, and the second change point at which f [iT] begins to saturate is a time that is 1T before nT. (N-1) T is set, and the output value of the signal at time (n-1) T is set to f [(n-1) T], and touch-on determination is performed (S615).

  Regarding the fourth threshold value Th4, when the third threshold value Th3 is divided by max (nm), the fourth threshold value Th4 increases as max {(nm) T} is shortened. The second difference value g1 [iT] tends to be smaller than the fourth threshold Th4. On the other hand, if a section in which the second difference value g1 [iT] is larger than the fourth threshold value Th4 continues in S604 by max {(nm) T}, Th4 = Th3 / max (nm). The difference (f [iT] −e [iT]) may be larger than the third threshold Th3, and the touch-on determination is made.

Here, when the first change point f [(m−1) T] is used instead of e [iT], f [iT] −f [(m−1) T]> Th3 is necessarily satisfied. The basis for this will be described below. g1 [iT] is a difference value between f [iT] and f [(i−1) T]. From time (m−1) T to time iT, each difference value g1 per section T is as follows.
G1 [iT] = f [iT] −f [(i−1) T]
G1 [(i-1) T] = f [(i-1) T] -f [(i-2) T]
G1 [(m + 1) T] = f [(m + 1) T] −f [mT]
G1 [mT] = f [mT] −f [(m−1) T]
Next, when g1 [mT] to g1 [iT] are added, except for f [iT] and -f [(m-1) T] on the right side is deleted, Equation 1 is obtained.
G1 [iT] + g1 [(i−1) T] +... + G1 [mT] = f [iT] −f [(m−1) T] (Formula 1)
Assuming that the interval in which g1 [iT]> Th4 in S604 is TRUE continues for max {(n−m) T}, Equation 2 is satisfied.
G1 [iT] + g1 [(i−1) T] +... + G1 [mT]> Th4 * max {(n−m) T} (Formula 2)
When g1 [iT] + g1 [(i−1) T] +... + G1 [(m) T], which is the left side of Equations 1 and 2, is deleted, f [iT] −f [(m− 1) T]> Th4 * max {(nm)}. Since Th4 = Th3 / max (nm) holds from the initial setting, Th4 and max (nm) are deleted, and f [iT] −f [(m−1) T]> Th3.
Here, f [(m−1) T] is the first change point, and if a section in which g1 [iT]> Th4 in S604 becomes TRUE continues for max {(n−m) T}, Th4 = From [Th3 / max (nm)], f [iT] -f [(m-1) T]> Th3 is necessarily satisfied. On the other hand, a case where the extrapolation point e [iT] is used will be described. The extrapolation point e [iT] is based on a gradual upward trend up to time (m−1) T, and after time (m−1) T, based on a gradual upward trend, Therefore, f [(m−1) T] <e [iT] is usually satisfied, and therefore f [iT] −e [(n−1) T]> Th3 does not necessarily hold.

  The extrapolation calculation mechanism 614 calculates the sum of the extrapolated values of the four channels at the time of touch-on determination as e [(n−1) T] = 2 * f [(m−1) T]] − f [(2mn− 1) Confirm to T]. The extrapolated value of each channel is ech [(n−1) T] = 2 * fch [(m−1) T]] − fch [(2m−n−1) T], and these extrapolated values Is stored in the extrapolation storage mechanism. Since touch-on has been determined so far, touch-off determination is entered next.

  Next, the threshold value calculation mechanism 608 sets f [iT] * α as the first threshold value Th1 for the touch-off determination, and stores it in the threshold value storage mechanism 609 (S616). Here, α is a parameter for calculating the first threshold Th1 for the touch-off determination, as in the first embodiment. For example, α is set to 0.6. Next, i is incremented by one (S617).

  Next, similarly to S602, the signal calculation mechanism 605 acquires the output value f [iT] of the signal (S618).

  Next, the difference calculation mechanism 611 calculates the second difference value g1 [iT] of the signal per third unit time in the same manner as S603 (S619).

  Next, the contact determination mechanism 610 compares the output value f [iT] of the signal with the first threshold Th1 (S620). When the output value f [iT] of the signal is smaller than the first threshold Th1, i is counted up by one (S621), and the process returns to S601. That is, the touch-off determination is made and the next touch-on is waited. On the other hand, when the output value f [iT] of the signal is greater than or equal to the first threshold Th1, the position calculation mechanism 616 determines the difference between the output value of each channel signal and the extrapolated value of each channel (fch [iT] −ech [ Based on (n-1) T]), the position of the indicator is calculated (S622). Here, ech [(n−1) T] corresponds to a palm signal component when the indicator is a finger. That is, the position of the indicator is calculated based on the value obtained by removing the palm signal component.

  Next, the change determination mechanism 613 compares the second difference value g1 [iT] calculated in S619 with 0 (S623). If the second difference value g1 [iT] is 0 or less, the process proceeds to S625 without going through S624. On the other hand, if the second difference value g1 [iT] is greater than 0, f [iT] * α is set as the first threshold value Th1 for new touch-off determination (S624). Next, i is incremented by one (S625), and the process returns to S618.

  In the sixth embodiment, the positional accuracy of the indicator can be improved by removing the influence accompanying the approach of the palm from the output value fch [nT] of the signal. Regarding the position accuracy, a steep signal change accompanying a touch, that is, a signal change per second unit time (nm) T becomes a signal (S) component, and a gradual signal change accompanying a palm approach, that is, a second unit time. A signal change before (nm) T becomes a noise (N) component. When the output value fch [iT] of the signal is saturated after the second change point, the second difference value g1 [iT] becomes smaller than the fourth threshold Th4 in S612. Here, the touch-on determination is made at time nT when the output value fch [iT] of the signal is saturated, and the first position coordinate after the touch is calculated at time (n + 1) T. By calculating the position coordinates after the output value fch [iT] of the signal is saturated, it is possible to extract a steep signal change accompanying the touch, that is, all signals, increase the S / N, and position coordinates for the first time after touching Can be calculated more accurately.

  In addition, in response to the position calculation in S622, there is a response from the touch sensor device such as a mouse event, but at time (n + 1) T when the output value fch [iT] of the signal is saturated, the fingertip and the panel surface are in good contact. Since it is immediately after, the time of the response from the touch sensor device is appropriate. Further, in S622, the position calculation is performed at time (n + 1) T, but can be performed at time nT.

  As described above, the second unit time for determining whether or not the touch is on is automatically adjusted based on the time change of the output value f [iT] of the signal before and after the touch, and the signal accompanying the approach of the palm is estimated. . Then, by removing the influence accompanying the approach of the palm, there is an effect of improving the positional accuracy while suppressing erroneous touch-on determination.

  For the extrapolated value calculation method calculated in S612, an approximate expression is calculated based on a gradual signal change before the first change point, and extrapolated from the first change point to time iT to obtain the extrapolated value. You can ask for it. For example, regarding the calculation method of the approximate expression, the linear approximate expression may be calculated by the least square method for fch [iT] of {(m−6) T to (m−1) T}. In this case, when noise is superimposed on fch [iT] and fch [iT] fluctuates, random noise is averaged and removed, so that the extrapolated value can be calculated more accurately.

  In S613 and S622, the extrapolated value is used for the signal accompanying the approach of the palm, but the first change point may be used. Compared to the extrapolated value, the calculation of the first change point is simple, and the calculation process can be greatly reduced.

  The other form of 6th Embodiment is the same as that of 1st Embodiment and 3rd Embodiment.

  Next, a touch sensor device according to a seventh embodiment will be described. FIG. 19 is a schematic cross-sectional view of the touch sensor device according to the seventh embodiment. FIG. 20 is a schematic plan view of the touch sensor device according to the seventh embodiment. In the first embodiment, the surface capacitive touch panel has been described as an example. In the seventh embodiment, a projection capacitive touch panel will be described as an example. FIG. 19 is a schematic sectional view of an LCD with a projected capacitive touch panel, and FIG. 20 is a schematic plan view thereof. In FIG. 20, the protective glass 705, the touch panel substrate 703, and the LCD 701 shown in FIG.

  A touch sensor device 700 disposed on the LCD 701 is formed on the LCD 701 and extends in the vertical direction in the drawing, a touch panel substrate 703 formed on the Y transparent electrode 702, and a touch panel substrate. Changes in the capacitances of a plurality of X transparent electrodes 704 formed on 703 and extending in the horizontal direction in the drawing, a protective glass formed on the X transparent electrode 704, and the X transparent electrode 704 and the Y transparent electrode 702 And a controller 706 for detecting. The X transparent electrode 704 and the Y transparent electrode are configured in a matrix shape.

  FIG. 20 shows a graph plotting the capacitance detected by each X transparent electrode 704 and a graph plotting the capacitance detected by each Y transparent electrode 702. In the touch sensor device 700, when the indicator 23 approaches the X transparent electrode 704 and the Y transparent electrode 702, the capacitance between the electrodes increases, and the controller 706 causes the capacitance of the X transparent electrode 704 and the Y transparent electrode 702 to increase. Is detected, and the position of the indicator 23 is detected. The electrostatic capacities of the X transparent electrode 704 and the Y transparent electrode 702 become maximum values near the contact of the indicator 23.

  Further, although the projection capacitive touch panel has been described as an example, the first threshold Th1 shown in the first embodiment may be applied to a touch switch that detects only touch on / off.

  The other form of 7th Embodiment is the same as that of 1st Embodiment.

[Example 1]
With respect to the touch sensor device according to the first embodiment, it was confirmed that there was a decrease in the signal transition during the drag operation while simulating the transition of the signal after the baseline correction. Changes in detection signal value h (iT) and signal output value f (iT) when the cover glass thickness is 0.5 mm and the proximity of the fingertip and palm is changed with respect to the touch panel. 21. h (iT) and f (iT) are converted from a voltage value to a capacitance value. The output value f (iT) of the signal was calculated based on Equation 5 above. The indicator was a fingertip.

  Referring to FIG. 21, the detection signal value h (iT) was 5 pF in the state where the human body such as the fingertip and the palm did not approach, but the signal output value f (iT) was almost 0 ( (T = 0 to 0.2 seconds in FIG. 21). This is because the signal accompanying the parasitic capacitance is canceled (canceled) by the baseline due to the baseline correction. Even in the state where a human body such as a fingertip and a palm is approaching, the signal accompanying the parasitic capacitance is canceled by the baseline, and the signal accompanying the user's action is extracted. At t = 0.2 to 0.7 seconds, the signal gradually increased due to the approach of a human body such as a palm. Next, the user tends to reconfirm the horizontal positional relationship between the fingertip and the icon displayed on the LCD after the palm is brought closer, and if the positional relationship is misaligned, the fingertip Adjust the position. Therefore, assuming that the fingertip is not in contact with the surface of the touch panel, but the distance between the surface of the touch panel and the palm is kept almost constant and there is no horizontal movement of the palm, the signal is almost constant at 4 pF. (T = 0.7 to 0.9 seconds).

  Next, when the fingertip touched the surface of the touch panel, the signal increased sharply to 10 pF (t = 0.9 to 0.95 seconds). Next, when the fingertip was stationary on the surface of the touch panel or a drag operation was performed, the signal increased or decreased at t = 1.15 to 3.75 seconds. There was a tendency for the signal to decrease during the drag operation, and the signal was the smallest at 6.5 pF when t = 2.35 seconds. When the first threshold is set to 6.5 pF or more, for example, the touch-off determination is made even during the touch-on.

  Next, when the fingertip was released from the surface of the touch panel, the signal decreased from 8 pF to 4 pF (t = 3.75 to 3.95 seconds). Next, the signal was constant at 4 pF when the fingertip was removed but the palm or arm was still approaching (t = 3.95 to 4.15 seconds). Next, as the palm and arms were moved away from the touch panel, the signal decreased. (T = 4.15-4.65 seconds). Thereafter, the signal became 0 pF (from t = 4.65 seconds).

  From this, it was confirmed that the signal might decrease during the drag operation in contact with the indicator, and it was also confirmed that there was a possibility of erroneous determination.

  FIG. 21 is a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm, and the detection signal value h (iT) under the same conditions as the above simulation. Was measured. FIG. 22 shows the measurement result of the detection signal value h (iT). FIG. 22 shows data before base correction, and stray capacitance is as high as about 100 pF. According to FIG. 22, it was confirmed that the signal may be lowered during the drag operation in which the indicator is in contact, as in the simulation result.

[Example 2]
For the signal transition obtained in the example, the first threshold value for touch-off determination is updated when the signal rises after touch-on determination, as in the flow according to the first embodiment shown in FIG. In the case of (or constant), the transition of the first threshold value was calculated by not updating the first threshold value. FIG. 23 shows the signal transition of the first threshold (Th1). The initial value of the first threshold was set to 8 pF. The transition of the signal is the same as in FIG.

  The fingertip touched the surface of the touch panel, the signal increased to 10 pF, and a touch-on determination was made (t = 0.9 to 0.95 seconds).

  Next, in the present embodiment, unlike the flowchart shown in FIG. 2, immediately after the touch-on determination is made (t = 0.95 seconds) without acquiring a new signal output value, the signal at the time of the touch-on determination is obtained. The output value 10 pF is compared with the output value 4 pF of the signal three times before. Since the output value of the signal when the touch-on determination is made is larger, the first threshold value after the touch-on determination is updated based on the output value 10 pF of the signal when the touch-on determination is made. Here, the sensitivity α is set to 0.6. From the first threshold Th1 = current signal (10 pF) * sensitivity (0.6), the new first threshold Th1 is calculated as 6 pF. Here, the current signal is a signal acquired in the same loop as the loop in which the signal is determined to be increasing. Here, since the signal associated with the parasitic capacitance is canceled by the baseline correction, when calculating the first threshold Th1 based on the current signal (10 pF), the component associated with the parasitic capacitance is also included in the first threshold Th1. Can be eliminated. In this way, even if the parasitic capacitance changes due to the manufacturing variation of the touch sensor device or the influence of the surrounding environment of the touch sensor device, the first threshold value Th1 can be appropriately set by the baseline correction.

  During the period when the signal is decreasing from 10.5 pF to 8.5 pF (t = 1.35 to 1.55 seconds), the first threshold Th1 remains 6.3 pF and is not updated. In the next step, the output value f [iT] of the signal is compared with the first threshold Th1, but the touch-off determination is not made because the signal is larger than the threshold.

  Next, in a period in which the signal output value f [iT] increases from 8.5 pF to 9 pF (t = 1.55 to 1.75 seconds), the first threshold Th1 is set to 5.1 pF to 5.4 pF. Updated. At t = 2.35 seconds, the signal output value f [iT] is the smallest 6.5 pF while the fingertip is touching, but the first threshold Th1 is updated to 4.5 pF, and the signal is the first Since it is larger than the threshold value Th1, a touch-off erroneous determination is not made.

  Here, for example, when the first threshold Th1 for the touch-off determination and the touch-on determination is constant at 8 pF, a touch-off erroneous determination is made. The reason why the effect of the present embodiment can be obtained is that the first threshold Th1 can be adjusted to be low when the signal generally decreases while the signal repeatedly increases and decreases.

  Next, in the period in which the fingertip is released from the surface of the touch panel and the signal decreases from 8 pF to 4 pF (t = 3.75 to 3.95 seconds), the signal decreases, so the first threshold Th1 is Not updated from 5.4 pF. When the output value f [iT] of the signal becomes smaller than the first threshold Th1, the touch-off determination is performed. In this way, when the fingertip is detached, the touch-off determination can be made reliably. This effect is due to the tendency of the signal to monotonously decrease when the fingertip is removed. Further, when the fingertip is removed, the signal decrease amount is large, and therefore, if the threshold value is not updated, the signal output value f [iT] is smaller than the first threshold value Th1. Next, although the fingertip has been released, the palm is approaching. At this time, the signal was constant at 4 pF (t = 3.95 to 4.15 seconds), but the touch-off determination has already been made when the fingertip is released.

  FIG. 23 shows a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm, and the signal output value f [iT under the same conditions as the above simulation. ] And the change in the first threshold value Th1 were measured. FIG. 24 shows measurement results of the signal output value f [iT] and the first threshold Th1. According to FIG. 24, it was confirmed that the signal decreased during the drag operation in contact with the indicator and the first threshold value Th1 could be adjusted to be low in the same manner as the simulation result.

[Example 3]
For the touch sensor device according to the second embodiment, the transition of the output value of the signal was simulated. FIG. 25 shows changes in the output value of the signal, the first threshold value, and the second threshold value. Since the output value of the signal when the palm is brought close to the touch panel is 4 pF, the second threshold Th2 is set to 8 pF, and is a constant that is not updated after the program starts.

  FIG. 25 is a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm, and the signal output value f [iT] under the same conditions as the above simulation. ], The change of 1st threshold value Th1 and 2nd threshold value Th2 was measured. FIG. 26 shows the measurement results of the signal output value f [iT], the first threshold Th1, and the second threshold Th2. According to FIG. 26, it was confirmed that the first threshold value Th1 changes similarly to the simulation result.

[Example 4]
The transition of the output value of the signal was simulated for the touch sensor device according to the third embodiment. FIG. 27 shows a graph showing the transition of the output value of the signal, the difference value, the first threshold value, and the second threshold value. In FIG. 27, the third threshold is not shown.

  When the palm approached the surface of the touch panel (t = 0.2 to 0.7 seconds), the output value of the signal gradually increased, and the difference value g2 [iT] was 0.4 pF. Next, when the palm is close to the surface of the touch panel, but the index finger is in the palm and is stationary (t = 0.7 to 0.9 seconds), the difference value g2 [iT] is almost 0 pF. Met.

  Next, when the fingertip touched the surface of the touch panel (t = 0.9 to 0.95 seconds), the output value of the signal rose steeply, and the maximum value of the difference value g2 [iT] during this period was 6 pF. Next, when the fingertip was stationary on the surface of the touch panel (t = 0.95 to 3.75 seconds), the difference value g2 was about 0.2 pF. When the fingertip is released from the surface of the touch panel (t = 3.75 to 3.8 seconds), the output value of the signal falls steeply, and the minimum value of the difference value g2 [iT] during this period is −6 pF. .

  Immediately after the fingertip was released (t = 3.8 to 4 seconds), the palm remained close to the surface of the touch panel, and the difference value g2 [iT] was almost 0 pF. Next, when the palm moved away from the surface of the touch panel (t = 4 to 4.5 seconds), the difference value g2 [iT] was −0.4 pF.

  Compared with the difference value g2 [iT] when the palm approaches, the difference value g2 [iT] when the fingertip contacts is 10 times or more. In addition, the difference value was almost 0 although the palm of the confused finger was approaching. It has been found that if the third threshold value Th3 is set between these difference values 0.4 pF to 6 pF, it is possible to discriminate between fingertip contact and palm approach.

  The difference value depends on the second unit time setting. For a signal change in a period shorter than the second unit time, the signal change can be extracted as a difference value as it is. On the other hand, for a signal change that lasts longer than the second unit time, the difference value decreases as the period becomes longer.

  Referring to FIG. 27, the rise time of the signal accompanying the fingertip contact was 50 msec, and the signal change accompanying the palm approach was 500 msec. In order to eliminate the signal change accompanying the approach of the palm, the second unit time should be as short as possible, and in order to extract the signal accompanying the fingertip contact, it is better not to be shorter than the rise time of the signal. Therefore, it is preferable to measure in advance the rise time of the signal accompanying the fingertip contact, and set the second unit time using the rise time or the rise time as a guide.

  Referring to FIG. 27, for the second unit time = 50 msec, the signal change accompanying the fingertip contact was 50 msec, so that 6 pF of the signal change accompanying the fingertip contact is extracted as it is as a difference value. On the other hand, the signal change accompanying the approach of the palm is 4 pF, whereas the difference value is 0.4 pF, which is reduced to about 1/10. Thus, it was found that by setting the second unit time over about 50 msec, it is possible to distinguish between a signal change associated with the fingertip contact and a signal change associated with the palm approach.

  FIG. 27 shows a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm, and the signal output value f [iT under the same conditions as the above simulation. ], The change of 1st threshold value Th1, 2nd threshold value Th2, and difference value g2 [iT] was measured. FIG. 28 shows the measurement results of the signal output value f [iT], the first threshold Th1, the second threshold Th2, and the difference value g2 [iT]. According to FIG. 28, it was confirmed that the same result as the simulation result was obtained.

[Example 5]
About the touch sensor which concerns on 3rd Embodiment, the transition of the output value of a signal and the difference value at the time of intentionally slowing down the operating speed of the separation of the indicator was simulated. FIG. 29 shows a graph showing the transition of the output value of the signal, the difference value, the first threshold value, and the second threshold value.

  When releasing the fingertip contact, the fingertip was gradually released over 1 second (t = 3.75 to 4.75 seconds). The difference value g2 [iT] at this time is −0.3 pF, which is almost the same as the −0.4 pF of the difference value g2 [iT] at t = 4.95 to 5.45 seconds when the palm moves away. From this, it was found that when only the difference value g2 [iT] is used as an index for touch determination, touch determination may be difficult. Accordingly, it has been found that it is preferable to use not only the difference value but also the output value of the signal described in the first embodiment for touch determination.

  FIG. 29 shows a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm, and the signal output value f [iT under the same conditions as the above simulation. ], The change of 1st threshold value Th1, 2nd threshold value Th2, and difference value g2 [iT] was measured. FIG. 30 shows the measurement results of the signal output value f [iT], the first threshold value Th1, the second threshold value Th2, and the difference value g2 [iT]. According to FIG. 30, it was confirmed that the same result as the simulation result was obtained.

[Example 6]
The correlation between the thickness of the cover glass and touch determination was examined. In FIG. 31, when the thickness of the cover glass is different, the transition of the output value of the signal when the surface of the touch panel and the fingertip are in contact with each other, and the distance between the palm and the surface of the touch panel is 10 mm. It shows the transition of the output value of the signal. FIG. 32 shows a graph showing changes in the output value of the signal with respect to the thickness of the cover glass. In addition, when the surface of the touch panel 901 and the fingertip 923 that is an indicator contact each other, the distance between the surface of the touch panel 901 and the palm is actually close to several centimeters. However, in FIGS. In order to extract the accompanying signal, the signal accompanying the palm approaching the surface of the touch panel 901 to several centimeters is ignored.

  When the thickness of the cover glass 937 as the protective layer is 0.3 mm, the “output value of the signal accompanying the contact of the fingertip 923” is larger than the “output value of the signal accompanying holding the palm”, so these signals If a threshold value is set between these output values, touch determination can be performed. However, when the thickness of the cover glass 937 is increased to 1.0 mm, the “signal associated with the fingertip contact” becomes smaller than the “signal associated with holding the palm”, and the magnitude relationship of the signal is reversed. Only by comparing the magnitude relationship of the signals, it is impossible to accurately determine the touch.

  FIG. 31 is a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm. The signal output value f [iT] under the same conditions as the above simulation. ] Was measured. FIG. 32 shows the measurement result of the signal output value f [iT]. In the measurement shown in FIG. 32, the thickness d of the protective layer was 0.2 mm. According to FIG. 32, it was confirmed that the same result as the simulation result was obtained.

Next, the output value of the signal accompanying the contact of the fingertip 923 and the output value of the signal accompanying holding the palm were calculated using a capacitance model of the parallel plate conductor. The capacitance C of an object in which a dielectric having a dielectric constant ε is uniformly filled between two parallel conductors having an area S [m ² ] and a distance d [m] is C = ε * S / d. Indicated. Here, ε = ε _r * ε ₀ , ε _r is the relative permittivity of the object, and ε ₀ is the vacuum permittivity of 8.8 × 10 ⁻¹² (F / m).

Referring to FIG. 32, the thickness dependency of the cover glass 937 of the output value of the signal accompanying the contact of the fingertip 923 and the output value of the signal accompanying holding the palm is shown. Regarding the calculation of the output value Cf of the signal accompanying the contact of the fingertip 923 (Equation 6), when the parallel flat plate is the fingertip 923 and the transparent conductive layer 939, the dielectric becomes the cover glass 937. Therefore, the relative dielectric constant is 4.0 of the cover glass 937, the area is the contact area between the fingertip 923 and the surface of the touch panel 901, 8 × 10 ⁻⁵ (m ² ), and the distance is the thickness of the cover glass 937. d (variable).

Cf = 8.8 × 10 ⁻¹² × 4 × 8 × 10 ⁻⁵ / d
= 2.8 × 10 ⁻¹⁵ / d (F) (Formula 6)

  On the other hand, regarding the calculation of the output value Ch of the signal accompanying holding the palm, the parallel conductor is the palm and the transparent conductive layer 939, and the dielectric is the atmosphere and the cover glass 937. Therefore, these capacitances were combined in series (Equation 7).

1 / Ch = 1 / Ca + 1 / Cc (Formula 7)
Here, Ca is the capacitance of the atmosphere, and Cc is the capacitance of the cover glass 937.

Regarding the calculation of the atmospheric capacitance Ca (Equation 8), the relative dielectric constant is 1.0 of air, the area is the palm area 5 × 10 ⁻³ (m ² ), and the distance is the palm and the surface of the touch panel 901. And the distance was 10 mm.

Ca = 8.8 × 10 ⁻¹² × 1 × 5 × 10 ⁻³ / 1 × 10 ⁻²
= 4.5 × 10 ⁻¹² (F) (Formula 8)

Regarding the calculation of the capacitance Cc of the cover glass 937 (Equation 9), the relative dielectric constant is 4.0 of the cover glass 937, the area is the palm area 5 × 10 ⁻³ (m ² ), and the distance is the cover glass 937. The thickness was d (variable).

Cc = 8.8 × 10 ⁻¹² × 4 × 5 × 10 ⁻³ / d
= 1.8 × 10 ⁻¹³ / d (F) (Formula 9)

From Equations 7, 8, and 9,
Ch = 1.8 × 10 ⁻¹³ /(d+0.04) (F) (Formula 10)

  In FIG. 32, as the cover glass 937 becomes thicker, the output value of the signal accompanying the contact of the fingertip 923 is significantly reduced, but the output value of the signal accompanying holding the palm is almost constant. When the cover glass 937 is thicker than 0.65 mm, the output value of the signal accompanying the contact of the fingertip 923 becomes smaller than the output value of the signal accompanying holding the palm, and the magnitude relationship is reversed. The thickness at which the magnitude relationship is reversed serves as a guide for the allowable range of the thickness of the cover glass 937. The reason for this is that referring to Equation 6, the output value Cf of the signal accompanying the contact of the fingertip 923 is inversely proportional to the thickness d of the cover glass 937. On the other hand, the output value of the signal accompanying holding the palm largely depends on the distance between the palm and the surface of the cover glass 937. Under the condition that this distance is kept constant, the output value depends on the thickness of the cover glass 937. The nature is very small. As described above, when the touch determination is made by simply comparing the magnitude relation of the capacitance, it is difficult to perform accurate touch determination when the cover glass 937 is thick.

  The same thing is manifested when the user wears gloves. That is, when a fingertip comes in contact, a part of the human body such as a palm or an arm approaches the touch panel, and a capacitance is formed by the palm and the transparent conductive layer. However, since the electrostatic capacitance formed by the fingertip wearing the gloves and the transparent conductive layer is small, the influence of the approach of the palm or the like is relatively increased.

  Therefore, a difference value (ΔCf) associated with the fingertip contact and a difference value ΔCh associated with the approach of the palm are calculated. The difference value (ΔCf) associated with the fingertip contact is calculated based on Equation 6, second unit time setting = 50 msec, and signal change time = 50 msec (Equation 11). The difference value (ΔCh) accompanying the approach of the palm is calculated based on Expression 10, second unit time setting = 50 msec, and signal change time = 500 msec (Expression 12).

ΔCf = Cf × (second unit time setting) / (signal change time)
= 2.8 × 10 ⁻¹² / d × 50 msec / 50 msec
= 2.8 × 10 ⁻¹² / d (Formula 11)
ΔCh = Ch × (second unit time setting) / (signal change time)
= 1.8 × 10 ⁻¹³ /(d+0.04)×50 msec / 500 msec
= 1.8 × 10 ⁻¹⁴ /(d+0.04) (Formula 12)
However, when (signal change time) ≦ (second unit time setting), (second unit time setting) / (signal change time) = 1.

  FIG. 34 shows the result of calculating the difference value by changing the thickness of the cover glass based on the equations 11 and 12. Referring to FIG. 34, the thickness of the cover glass where the difference value accompanying the approach of the palm is larger than the difference value accompanying the fingertip contact was 7.2 mm. Compared with the case where only the magnitudes of the signals in FIG. 32 are compared, when the difference value is used as an index for touch determination, there is a remarkable effect that the allowable range of the thickness of the cover glass becomes about 10 times.

  Next, since the influence of the approach of the palm was greatly reduced, it became possible to detect a smaller capacitance change. When a glove is attached to the bare hand and touches the surface of the touch panel, a capacitance is formed between the fingertip and the transparent conductive layer. A glove and a cover glass exist between the fingertip and the transparent conductive layer, and the capacitance is a series connection of the capacitance accumulated in the glove and the cover glass. If the relative dielectric constants of the glove and the cover glass are approximated to be equal, it can be regarded as equivalent to a thicker cover glass corresponding to the thickness of the glove.

  FIG. 35 shows the result of simulating the transition of the output value of the signal, the difference value, and the first threshold value by wearing vinyl gloves. In FIG. 35, the first threshold Th1 is not shown. A glove made of vinyl having a thickness of 0.5 mm was used. Compared to the case of bare hands (bare fingers) such as in FIG. 28, the difference value associated with contact when wearing a glove is about ½ with 3 pF. Compared with the value 0.4 pF, the difference value 3 pF accompanying the contact is sufficiently large, and it was confirmed that the approach of the palm and the contact of the fingertip can be discriminated if the third threshold Th3 is set between them. Also, if the third threshold Th3 is set smaller than the difference value 3 pF associated with contact when wearing gloves, the signal when touching with bare hands is larger than when wearing gloves. It was also confirmed that the touch determination can be accurately performed in both cases of contact of the attached fingertip and bare fingertip. For example, it is preferable to set th3 between 30% and 100% of the signal 3 pF accompanying contact when wearing gloves.

  FIG. 35 is a simulation result assuming a time change of f [iT] accompanying the touch and a time change of f [iT] accompanying the approach of the palm. The signal output value f [iT] under the same conditions as the above simulation. ], Changes in the first threshold Th1 and the difference value g2 [iT] were measured. As a glove, a synthetic resin material having a wall thickness of 0.20 mm was used. FIG. 36 illustrates measurement results of the signal output value f [iT], the first threshold Th1, and the difference value g2 [iT]. According to FIG. 36, it was confirmed that accurate touch determination was possible even when gloves were used.

  By using the difference value as an index for touch determination, it was found that the influence of the approach of the palm can be greatly reduced, so that the approach of the palm and the contact with the fingertip can be discriminated. Thereby, it becomes possible to use a thicker cover glass and to input by wearing gloves.

[Example 7]
The output value of the signal was simulated while changing the distance between the touch sensor device and the indicator. FIG. 37 shows a schematic perspective view of a testing machine used for measurement. The same reference numerals as those in the first embodiment are used for configurations that are substantially the same as those in the first embodiment. The testing machine 90 is provided with a stage 84, and the electronic device 1 is arranged on the stage 84 with the surface of the touch panel 101 facing up. The tip 80a of the indicator (rigid body) 80 is a conductor, and the tip 80a and the circuit ground (reference potential node) in the tester 90 are electrically connected (not shown). Even if the area of the lower surface of the tip 80a is 35 (cm ² ), which is about 40 times the contact area of the fingertip, and the distance L between the indicator 80 and the surface of the touch panel 101 is several millimeters, the indicator 80 Between the transparent conductive layer 39 and the transparent conductive layer 39, a capacitance equivalent to the capacitance associated with the fingertip contact is formed. The surface of the main body 80b of the indicator 80 is insulative, and the distance sensor device 82 is attached to the side surface. The distance sensor device 82 is provided with a display (not shown) on which the measurement result of the distance L is displayed. The main body 80b and a unit 86 incorporating a motor for controlling the height of the indicator 80 are connected. A unit 86 and a stand 88 are connected.
The testing machine 90 has a built-in microcontroller (not shown), and automatically controls the distance L between the surface of the touch panel 101 mounted on the electronic device 1 and the indicator 80 by a program incorporated in the microcontroller. The distance L between the touch panel 101 and the indicator 80 at that time is monitored. When the indicator 80 is moved up and down, the capacitance detected by the touch sensor device 100 when the surface of the touch panel 101 is dragged or the capacitance when the fingertip is removed from the surface of the touch panel 101 is increased. It becomes possible to give a signal equivalent to monotonous decrease. That is, it is possible to give the touch sensor device 100 from the testing machine 90 the same capacitance change as when the user operates the touch sensor device 100. In addition, when the touch sensor device 100 receives a capacitance change and the touch sensor device 1 transmits information such as a mouse event to the outside, the function of the present invention mounted on the touch sensor device 100 can be examined more objectively. It becomes possible.

  FIG. 38 shows a simulation transition of the output value of the signal, the first threshold value, and the distance when the indicator 80 is monotonously raised. The distance L measured by the distance sensor device 82 is also shown. As the value of the signal output value f [iT], the first threshold Th1, and the second threshold Th2, the scale of the capacitance on the left vertical axis of the graph was used. For the value of the distance L, the distance scale on the right vertical axis was used. Also in FIG. 39, the method of using the vertical axis of the graph is the same as in FIG. As a touch determination program of the touch sensor device 100, the flow shown in 8 according to the second embodiment is used.

  First, the distance L between the surface of the touch panel 101 and the indicator 80 is kept at 30 mm (time elapse t = 0 to 5 seconds). Next, when the indicator 80 is moved closer to the surface of the touch panel 101, a touch-on determination is made when the output value f [iT] of the signal becomes larger than the second threshold Th2 = 8 pF. At this time, the pointer displayed on the display device mounted on the electronic device 1 is selected. Next, when the distance L between the surface of the touch panel 101 and the indicator 80 approached 3 mm, the output value of the signal became constant at 10 pF (t = 15 to 20 seconds). The first threshold value Th1 for the touch-off determination at this time was 6 pF.

  Next, as the distance L between the surface of the touch panel 101 and the indicator 80 was increased, the capacitance monotonously decreased (t = 20 to 95 seconds). When the first threshold Th1 is not updated from 6 pF and the output value f [iT] of the signal becomes smaller than the first threshold Th1, the touch-off determination is made. The signal at this time was 6 pF, and the distance L was 5.1 mm (t = 53.5 seconds).

  FIG. 39 shows a simulation transition of the output value of the signal, the first threshold value, and the distance when the indicator 80 is moved away from the surface of the touch panel 101 while repeatedly raising and lowering the indicator 80. Up to the touch-on determination, the operation is the same as that in FIG.

  By repeatedly raising and lowering the indicator 80, the indicator 80 was separated from the surface of the touch panel 101 (t = 20 to 95 seconds). As the indicator 80 moves away from the surface of the touch panel 101, the output value f [iT] of the signal generally decreases. However, the indicator 80 and the surface of the touch panel 101 once approach each other during the period when the indicator 80 is lowered. Since the signal output value f [iT] increases and the first threshold value Th1 is updated, the first threshold value Th1 generally decreases with time. When the output value f [iT] of the signal is smaller than the first threshold Th1, the touch-off determination is made. The signal at this time was 2.4 pF, and the distance L was 12.8 mm (t = 84 seconds).

  Comparing the test result of FIG. 38 with the test result of FIG. 39, the distance L when the touch-off determination is made is different. That is, when the indicator 80 is repeatedly moved up and down and the indicator 80 is moved away from the surface of the touch panel 101, the distance L when the touch-off determination is made becomes longer. Compared with the case where the indicator 80 is monotonously raised, there is a period in which the first threshold Th1 for touch-off is updated when the indicator 80 is repeatedly lifted and released, so that the capacitance when the touch-off determination is made This is due to the decrease.

  Next, frequency setting for signal increase / decrease will be described with reference to FIG. The signal output value f [iT] decreases at t = 20 to 25 seconds, and the signal output value f [iT] increases at t = 25 to 30 seconds. Assuming that one period (signal increase / decrease period) is t = 20 to 30 seconds that increase after the signal decreases, the signal increase / decrease period is 10 seconds here. Since the frequency is the reciprocal of the period, the frequency at which the signal increases or decreases is 0.1 Hz. Here, the output value of the signal is almost inversely proportional to the distance L, and the increase / decrease of the output value of the signal is controlled by the raising / lowering of the indicator 80. Therefore, the frequency of the signal increase / decrease is the same as the raising / lowering frequency of the indicator 80. Value.

  Next, the amount of increase in the distance of the indicator 80 per cycle of signal increase / decrease in the operation of raising and lowering the indicator 80 will be described with reference to FIG. The signal output value f [iT] decreases from 10 pF to 8 pF between t = 20 and 25 seconds, and the signal output value f [iT] increases from 8 pF to 9 pF at t = 25 to 30 seconds. . Accordingly, in one cycle of signal increase / decrease, since 1 pF is increased after decreasing by 2 pF, when these are added, 1 pF is decreased. In every period of signal increase / decrease, the signal decrease amount is 2 pF and the signal increase amount is 1 pF.

  When the first signal increase / decrease (t = 20 to 30 seconds) is the first period and the qth period is the qth period, the signal is changed from 4 pF to 2 pF during the seventh period t = 80 to 85 sec. When decreasing, the output value of the signal became smaller than the first threshold Th1, and the touch-off determination was made. This is because the output value of the signal generally decreases as the q-th period becomes later, and therefore the signal decrease per one period of signal increase / decrease becomes relatively large with respect to the signal at that time. Specifically, since the first threshold value Th is calculated by the first threshold value Th1 = signal c in contact × sensitivity (α = 0.6), the output value of the signal is 40% or more in one cycle of signal increase / decrease. If there is a decreasing period, the output value of the signal becomes smaller than the first threshold Th1, and a touch-off determination is made.

[Example 8]
The transition of the output value of the channel signal was measured for the touch sensor device according to the sixth embodiment. The setting conditions were the same as in the example shown in the sixth embodiment. FIG. 40 shows a graph showing the transition of the output value of the channel signal. FIG. 41 is a graph showing the transition of the sum of the output values of the four channel signals. In the eighth embodiment, when the difference value of the signal per second unit time (nm) T is larger than the third threshold Th3 = 1.5 pF, the touch-on determination is made. Here, the second unit time was set to (nm) T = 2 * 16 milliseconds = 32 milliseconds. The second unit time in FIG. 40 does not include a gradual signal change before this time, and extracts a signal change that is rapidly rising. If the algorithm of 6th Embodiment is used, the signal accompanying the approach of a palm and the signal accompanying a touch can be distinguished.

  Since the upper limit value of the second unit time (nm) T is initially set to max {(nm) T} = 80 milliseconds, it is automatically set to 16 milliseconds to 80 milliseconds depending on the situation of each touch. Adjusted to. Here, a test was performed in which the palm was brought close to the panel surface and stopped just before the palm and the panel surface contacted each other. When max {(n−m) T} was 160 milliseconds, touch-on determination was made in this test. This is an erroneous determination because the indicator and the panel surface are not in contact. On the other hand, when the upper limit value max {(n−m) T} = 80 milliseconds, the touch-on determination was not made. Therefore, by automatically adjusting the second unit time (n−m) T and setting it to max {(n−m) T} = 80 milliseconds, erroneous touch-on determination due to the approach of the palm can be suppressed. I understand.

  Next, in order to verify the effect of the sixth embodiment, the index surface of the right hand was used to touch the panel surface, and the position of the pointer calculated by the touch sensor device was measured. FIG. 42 shows what is explained in FIG. First, the effect of palm approach will be described. When the position of the indicator 23 is simply calculated based on fch [nT] immediately after the touch-on, the position of the pointer 630 is +8 mm (right direction) in the X direction with respect to the position where the panel surface and the finger are in contact with each other. The direction was shifted by -20 mm (in front of the touching person). The palm of the right hand is generally located in front of the right index finger of the touched right hand and matches the direction of the pointer misalignment. The cause of the misalignment of the pointer is the effect of the approach of the palm. I understand that. On the other hand, when a signal with the approach of the palm is removed from fch [(nT)] immediately after touch-on and the position is calculated, the positional deviation of the pointer 630 is 1 mm in both the X and Y directions from the contact position of the finger. The following was greatly improved.

[Example 9]
Changes in the output value f [iT] of the signal and the first threshold Th1 were measured using the touch sensor device according to the seventh embodiment. Setting conditions such as threshold update are the same as in the third embodiment. FIG. 43 shows measurement results of the signal output value f [iT] and the first threshold Th1. The total capacitance detected by all the X transparent electrodes 704 and the Y transparent electrodes 702 is defined as a capacitance f [iT] accompanying the touch. T was 16 milliseconds. The output value f [iT] gradually increased from almost zero at first, then increased rapidly and then saturated. Similarly to the first embodiment, the touch-on determination is performed while f [iT] is rapidly increasing, and the first threshold Th1 that is the threshold for touch-off is calculated based on f [iT].

  Here, the output value f [iT] of the signal is the sum of the capacitances detected by all the X transparent electrodes 704 and the Y transparent electrodes 702, but the maximum value of the capacitance in the X direction and the static value in the Y direction. You may use the value which totaled the maximum value of electric capacity.

  The touch sensor device, the control method thereof, the electronic device, and the program of the present invention have been described based on the above embodiment, but are not limited to the above embodiment, and are within the scope of the present invention. It goes without saying that various modifications, changes and improvements can be included in the above embodiment based on the basic technical idea. Further, various combinations, substitutions, or selections of various disclosed elements are possible within the scope of the claims of the present invention.

  Further problems, objects, and developments of the present invention will become apparent from the entire disclosure of the present invention including the claims.

  INDUSTRIAL APPLICABILITY The present invention can be used for a surface display device that detects a position coordinate pointed by using a pointer on a display surface, or a surface display device that detects the presence or absence of a pointing operation. As examples of use of the present invention, it is used for game machines, personal digital assistants, PDAs, car navigation systems, notebook computers, portable DVD players, TV / game machines attached to airplanes and buses, and factory automation (FA) equipment. Touch sensor function.

  All the items described in the earlier application that is the basis of the priority based on the claim of domestic priority shall not be affected at all by the description added or changed in the present application. Is valid and should be interpreted as such. In addition, in the present application, the added or changed description matters are set as the reference date on the filing date of the present application.

1,401 Electronic equipment 3 Housing 5 LCD
7 FPC
18 Power supply device 19 Main board 21 Controller 23 Finger (indicator)
25 Capacitance associated with touch 26 Parasitic capacitance 27 AC voltage source (power supply)
28c Current-voltage conversion circuit 29a to 29d Current detection circuit (current detection unit)
35 Ground potential (earth potential)
37 Protective layer (cover glass)
38 Electrode 39 Transparent conductive layer (impedance surface)
DESCRIPTION OF SYMBOLS 41 Insulation board | substrate 50 Operational amplifier 52 Resistance element 54a-54d AC-DC conversion circuit 56 Analog-digital conversion circuit 58 Microcontroller 60 CPU
62 Flash memory 80 Indicator (rigid body)
80a Pointer of indicator 80b Main body of indicator 82 Distance sensor device 84 Stage 86 Height control unit of indicator 88 Stand 90 Tester 100, 300, 400, 600 Touch sensor device 101, 301, 601 Touch panel 102, 302 , 602 Signal acquisition mechanism 103, 303, 603 Reference calculation mechanism 104, 304, 604 Reference storage mechanism 105, 305, 605 Signal calculation mechanism 106, 306, 606 Signal comparison mechanism 107, 307, 607 Signal storage mechanism 108, 308, 608 Threshold calculation mechanism 109, 309, 609 Threshold storage mechanism 110, 310, 610 Contact determination mechanism 311, 611 Difference calculation mechanism 402 Liquid crystal element (liquid crystal)
403 Display area 404 Signal line 405 Pixel electrode 406 Scan line 408 Storage capacitor line 410 TFT substrate 411 TFT
412 Counter electrode (transparent conductive layer, impedance surface)
414 Scan line drive circuit 415 Signal line drive circuit 416 First high impedance switch part (high impedance switch part of data line)
417 Second high impedance switch part (high impedance switch part of gate line)
418 Third high impedance switch section (high impedance switch section of storage capacitor line)
419 Counter substrate 430a to 430d Electrode 421 COM-current detection circuit changeover switch part (switch part)
434 Anisotropic conductor 438 LCD FPC
501 Position detection conductive layer (transparent conductive layer, impedance surface)
612 Difference storage mechanism 613 Change determination mechanism 614 Extrapolation calculation mechanism 615 Extrapolation storage mechanism 616 Position calculation mechanism 630 Pointer 700 Touch sensor device 701 LCD
702 Y transparent electrode 703 Touch panel substrate 704 X transparent electrode 705 Protective glass 706 Controller 901 Touch panel 923 Indicator 937 Protective layer (cover glass)
939 Transparent conductive layer (impedance surface)
941 Insulating substrate Th1 to Th3 First to third threshold values f [iT] Signal output value g _i [iT] Difference value COM Common electrode

Claims (4)

A touch panel in which capacitance is formed between the indicator and
A signal calculation mechanism for calculating an output value of a signal corresponding to the magnitude of the capacitance;
With
When it is determined that the indicator and the touch panel are in contact with each other when the indicator is brought close to the touch panel, the indicator and the touch panel are increased when the distance between the indicator and the touch panel is monotonously increased. A first distance between the indicator and the touch panel when it is determined that it has left;
When it is determined that the indicator and the touch panel are in contact with each other when the indicator is brought close to the touch panel, the indication is increased when the distance between the indicator and the touch panel is gradually increased and decreased. A second distance between the indicator and the touch panel when it is determined that the body and the touch panel have separated;
In the touch sensor device, the first distance is shorter than the second distance.   An electronic apparatus comprising the touch sensor device according to claim 1. A counter electrode that also serves as a conductive layer that forms a capacitance with the indicator;
Wiring and
A liquid crystal interposed between the counter electrode and the wiring;
The electronic apparatus according to claim 2, further comprising a switch unit that floats at least a part of the wiring. A counter electrode;
Wiring and
A liquid crystal interposed between the counter electrode and the wiring;
A conductive layer that forms a capacitance with the indicator;
An insulating substrate provided between the counter electrode and the conductive layer;
The electronic apparatus according to claim 2, further comprising: a switch unit that simultaneously applies an alternating voltage applied to the conductive layer surface to the counter electrode.

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