JP5656666B2 - Touch panel device - Google Patents

Description

  The present invention detects, for example, the capacitance of a plurality of detection electrodes arranged on a touch panel, and a position where a detection target such as a user's finger or stylus pen touches the touch panel, or close to the touch panel. The present invention relates to a touch panel device that identifies a position where the user is present.

In recent years, mobile terminals, liquid crystal display devices and the like equipped with a touch panel have been widely used.
One method of the touch panel is a projection capacity method. Since this method is excellent in transmittance and durability, its use is expanded, and it is possible to detect both contact with a user's finger or a touch panel such as a stylus pen and proximity to the touch panel.
However, in the case of an electrostatic sensor using a projection capacitance method, the output capacitance value varies due to temperature changes, environmental variations (such as the influence of peripheral devices), etc., so the touch panel uses absolute capacitance values. It is difficult to detect the proximity or contact of a finger or the like. For this reason, the capacitance value when the finger or the like is not touching the sensor electrode of the touch panel is used as a reference capacitance (baseline value), and the difference between the capacitance values detected from that value is used to determine the proximity of the finger. A method for detecting contact (sensitivity calibration) is disclosed (see, for example, Patent Document 1).

JP 2007-208682 A

  In the conventional method, the capacitance value is not measured when the finger is not in contact with the touch panel due to sudden environmental changes such as contact with things such as PET bottles or mobile phones, or temperature rise in a sealed space. If the threshold value for touch determination is exceeded, calibration is not executed when the finger touches, so the baseline value is set to normal unless you continue to wait until the environment returns to normal or you give a processing command such as reset from the outside. There was a problem that it was not possible to return to the state.

  The present invention has been made to solve the above-described problems, and the output of the finger contact determination continues because the capacitance value cannot normally occur by finger operation, for example, the capacitance value suddenly decreases. It has a means to determine the abnormal state, etc., and restore the baseline value, so that the finger contact judgment is wrongly output due to the contact of things such as PET bottles or mobile phones or sudden changes in the environment. Enables automatic recovery from continuing abnormalities.

The touch panel device according to the present invention includes:
A plurality of detection electrodes whose capacitance changes due to the contact and proximity of the detection object;
A capacitance detecting means for detecting a capacitance between the detection electrode and the detection object;
Baseline storage means for storing a baseline value which is a capacitance value serving as a reference for detecting the proximity or contact of the detection object;
A proximity-contact detection means to determine the state of the proximity or contact touch of the resultant capacitance value and the detection object by the baseline value by the capacitance detecting means,
Baseline update means for updating the baseline value of the baseline storage means with the capacitance value and the baseline value obtained by the capacitance detection means;
An abnormal state that detects an abnormal state of each detection electrode that cannot occur by finger operation from the finger state detected by the proximity / contact detection means, the baseline value of the plurality of detection electrodes, and the capacitance value distribution of the plurality of detection electrodes Detection means;
Comprising control means for controlling each means,
The control unit controls the baseline value of the baseline storage unit to be updated by the baseline update unit when the abnormal state detection unit determines that the abnormal state is detected. When the distribution of the difference value obtained from the capacitance value is obtained in the direction opposite to that when the finger is touched, the abnormal state is determined .

  According to the touch panel device according to the present invention, the finger contact output is continuously output. Alternatively, if the capacitance value cannot occur by finger operation, an abnormal state detection unit that detects an abnormal state is provided, and the baseline update unit performs calibration to determine the proximity / touch state of the detection target. Since the baseline value, which is the determination reference value, is reset and can be automatically restored, the safety and maintainability of the touch panel can be further improved.

It is a block diagram which shows the touchscreen apparatus by Embodiment 1 of this invention. 3 is a flowchart of control means in the first embodiment. It is a characteristic view showing the capacitance value (black bar) and the baseline value (hatched bar) of the detection electrode in the touch panel device of FIG. It is a figure which shows the dielectric constant of a substance. FIG. 4 is a graph showing a difference between baseline values and capacitance values in FIG. 3. It is a figure which shows the baseline update value updated by the baseline update means and stored in the baseline storage means. It is a block diagram of a touch panel device showing a state in which a finger or an object is not in proximity to or in contact with a detection electrode. FIG. 8 is a graph showing the capacitance value and the baseline value of the detection electrode in the state of FIG. 7. It is the figure which made the difference of the baseline value from the electrostatic capacitance value of the detection electrode in FIG. 8, and graphed. It is the figure which graphed the electrostatic capacitance value of the detection electrode at the time of rapid temperature rise, and a baseline value. It is the figure which graphed the difference of the baseline value from the electrostatic capacitance value of the detection electrode in FIG. It is a block diagram of the touch panel apparatus which shows the state which the water droplet adhered to the touch panel with a frame. It is sectional drawing of a part of touchscreen part with a frame. It is sectional drawing of a part in the state in which the water droplet adhered to the touchscreen part with a frame. It is the figure which made the electrostatic capacitance value and base line value of the detection electrode in the state of FIG. 12 into a graph. It is the figure which made the difference of the baseline value from the electrostatic capacitance value of FIG. 15 into a graph. It is the figure which graphed the difference of the baseline value from the electrostatic capacitance value of the detection electrode in the contact state of a finger. It is the figure which graphed the difference of the baseline value from the capacitance value of the detection electrode in the contact state of the thing that is not a finger.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a touch panel device according to Embodiment 1 of the present invention. In the figure, X-direction detection electrodes 2a to 2e and Y-direction detection electrodes 2f to 2j are arranged below a transparent glass surface 1. The capacitance changes depending on the detection object such as the user's finger or stylus pen (hereinafter, represented by the finger unless necessary) or the proximity / contact of the dielectric 5 such as a plastic bottle or a mobile phone.
Upon receiving the detection instruction signal from the control unit 4, the capacitance detection unit 3 sequentially detects the capacitance of the detection electrodes 2a to 2j in the X direction and the Y direction, and updates the proximity / contact detection unit 7 and the baseline. The detected capacitance value is output to the means 8. Upon receiving the instruction signal from the control means 4, the baseline update means 8 obtains the baseline values of the detection electrodes 2a to 2j using the capacitance value from the capacitance detection means 3, and stores the baseline. Output to means 9. The baseline storage unit 9 stores the baseline value output from the baseline update unit 8 in response to a storage instruction signal from the control unit 4. The proximity / contact detection means 7 is based on the capacitance value output from the capacitance detection means 3 and the baseline value output from the baseline storage means 9 based on the detection instruction signal from the control means 4. The proximity or contact of a finger or the like is detected, and the presence / absence information is output.
Further, in accordance with the baseline output instruction signal of the control means 4, the proximity / contact detection means 7 provides information on the presence or absence of proximity or contact of the user's finger or the like, or the baseline storage means 9 indicates the stored baseline value. Output.

  FIG. 3 shows the capacitance values (black bars) of the detection electrodes 2a to 2j obtained by the capacitance detection means 3, and the baseline values (hatched bars) of the detection electrodes 2a to 2j stored in the baseline storage means 9. ). Generally, the capacitance value generated between the finger (virtual ground electrode) and the detection electrode is (dielectric constant of vacuum) × (dielectric constant of the substance between the finger and detection electrode) × (overlap of detection electrode and finger) Area) / (distance between finger and detection electrode). Here, the dielectric constant of the substance is (vacuum permittivity) × (substance relative permittivity), and the vacuum permittivity is fixed. Therefore, the larger the relative permittivity of the substance, the greater the gap between the finger and the detection electrode. The capacitance value generated in the case becomes large.

  Here, when the electrostatic sensor is a transparent type electrostatic touch panel as shown in the configuration diagram of FIG. 1, a transparent electrode such as ITO (indium tin oxide) is used as a detection electrode, but usually, the upper surface of the electrode is for protection. Glass, acrylic, or the like is provided, and finger contact with the glass or acrylic surface is detected. Even in this case, as shown in the relative permittivity table of the substance in FIG. 4, since the relative permittivity of air is smaller than that of glass, acrylic, etc., there is an air layer between the glass, acrylic surface and the finger. In the case of (proximity / approaching state) and a case where a finger or an object (such as a mobile phone or a plastic bottle) contacts the glass or acrylic surface, the capacitance value detected in the latter state is larger. Using this change, detection of contact of a finger or an object with the detection electrode is performed. Here, F (farad) is used as the unit of the capacitance value. Generally, the method for detecting the capacitance value between the finger and the electrode is a method for measuring a variation in charge / discharge time, a sine wave, Since there are various methods such as a method of measuring a voltage change such as a rectangular wave, the unit of the capacitance value in the description in the present invention is expressed as a normalized scale.

  FIG. 3 shows a capacitance value and a baseline value in a state where the PET bottle is in contact with the detection electrodes 2c and 2h as shown in FIG. In FIG. 3, since the PET bottle is in contact with the detection electrodes 2c and 2h, a capacitance distribution having a peak at 2h on the detection electrode 2c and on the Y side is obtained.

4 is a diagram showing the relative dielectric constant of the substance, and FIG. 5 is a baseline value stored in the baseline storage means 9 from the capacitance value obtained by the capacitance detection means 3 shown in FIG. The difference is shown in a graph. In FIG. 5, 20 is a threshold value for a proximity state that is determined to be a proximity state, and 21 is a threshold value for a contact state that is determined to be a contact state.
In FIG. 5, since the PET bottle 5 is in contact with the detection electrodes 2c and 2h as shown in FIG. 1, the capacitance value of the detection electrode 2c exceeds the threshold value 21 for the contact state, and the detection electrode 2h The electrostatic capacitance value approaches the threshold value 21 for the contact state as much as possible.
FIG. 6 is a diagram showing updated baseline values updated by the baseline update unit 8 and stored in the baseline storage unit 9.

  FIG. 7 is a configuration diagram of the touch panel device showing a state in which a finger or an object is not in proximity to or in contact with the detection electrode, and FIG. 8 is a capacitance obtained by the capacitance detection means 3 in the state of FIG. FIG. 6 is a graph of the baseline value stored in the value and baseline storage means 9. 9 shows the baseline value stored in the baseline storage means 9 from the capacitance value obtained by the capacitance detection means 3 in the state of FIG. 7, that is, the baseline value from the capacitance value shown in FIG. FIG.

  FIG. 10 is a graph showing the capacitance value obtained by the capacitance detection means 3 and the baseline value stored in the baseline storage means 9 when the temperature rises rapidly. FIG. 11 shows the baseline value stored in the baseline storage means 9 from the capacitance value obtained by the capacitance detection means 3 at the time of rapid temperature rise, that is, from the capacitance value shown in FIG. It is the figure which graphed the difference of the line value.

  FIG. 12 is a configuration diagram of the touch panel device showing a state in which water droplets are attached to the touch panel with a frame. FIG. 13 is a cross-sectional view of a part of the touch panel in a state where no water droplets are attached in the configuration of the touch panel device shown in FIG. 12, and the detection electrodes 2d, 2e, and 2j and the frame 11 (the metal part 12 included in the frame). It is a figure which shows generation | occurrence | production of the electrostatic capacitance between. FIG. 14 is a cross-sectional view of a part of the touch panel in a state where water droplets are attached in the configuration of the touch panel device shown in FIG. 12, and between the detection electrodes 2d, 2e, and 2j and the frame 11 (the metal part 12 included in the frame). It is a figure which shows generation | occurrence | production of an electrostatic capacitance.

  FIG. 15 is a graph of the capacitance values of the sensing electrodes 2a to 2j obtained by the capacitance detection means 3 in the state of FIG. 12 and the baseline values stored in the baseline storage means 9, 16 shows the baseline values stored in the baseline storage means 9 from the capacitance values of the sensing electrodes 2a to 2j obtained by the capacitance detection means 3 in the state of FIG. 12, that is, the electrostatic values shown in FIG. It is the figure which graphed the difference of the baseline value from the capacitance value.

  FIG. 17 shows the difference between the capacitance value of the sensing electrodes 2a to 2j obtained by the capacitance detection means 3 and the baseline value stored in the baseline storage means 9 in a state where the finger or stylus is in contact. FIG. 18 is a graph, and FIG. 18 shows the capacitance values of the sensing electrodes 2a to 2j obtained by the capacitance detection means 3 and the baseline storage means 9 stored in a state where an object such as a mobile phone is in contact. It is the figure which graphed the difference value of the made baseline value.

Next, the operation in the abnormal state in which the plastic bottle 5 is placed on the touch panel, that is, the state in FIG. 1 will be described using the flowchart of the control means 4 in FIG.
The control means 4 instructs the capacitance detection means 3 in ST1, and the capacitance detection means 3 sequentially detects the capacitance values of the detection electrodes 2a to 2j, and detects the detected capacitance values in proximity. Output to the contact detection means 7 and the baseline update means 8. The detected capacitance value is indicated by a black bar in FIG. Since the PET bottle 5 is in contact with the X-side detection electrode 2c and the Y-side detection electrode 2h as shown in FIG. 1, the capacitance values of the detection electrodes 2c and 2h are large in FIG.

  Next, in ST2, the control unit 4 instructs the proximity / contact detection unit 7, and the proximity / contact detection unit 7 approaches the proximity of the finger based on the obtained capacitance values of the detection electrodes 2a to 2j. Alternatively, the contact state is detected. Specifically, a difference value between each of the detection electrodes 2a to 2j and the baseline value for each of the detection electrodes 2a to 2j stored in the baseline storage means 9 is obtained from the capacitance value of each of the detection electrodes 2a to 2j, and the difference value and proximity state detection are obtained. The proximity and the contact state are detected by comparing the threshold value for use and the threshold value for detecting the contact state. The baseline value in the example of FIG. 1 is the hatched bar shown in FIG. 3, and the black bar in FIG. 5 shows the difference from the capacitance value. As shown in FIG. 5, since the capacitance value of the detection electrode 2c exceeds the threshold value 21 for the contact state, it is determined that the contact state of a dielectric such as a finger or a plastic bottle.

  Next, in ST3, the control means 4 instructs the proximity / contact detection means 7, and the proximity / contact detection means 7 determines whether or not the finger is in proximity or contact. If yes, go to ST4, otherwise go to ST5. Here, since it was a contact state in ST3, it progresses to ST4.

  In ST4, the control means 4 instructs the proximity / contact detection means 7, and the proximity / contact detection means 7 outputs the proximity / contact state of a dielectric such as a finger or a plastic bottle determined in ST2.

  Next, in ST5, the control unit 4 instructs the abnormal state detection unit 10, and the abnormal state detection unit 10 continues to issue a finger contact determination or occurs when the capacitance value is a finger (or derivative) contact. The presence / absence of an abnormal state is determined based on the determination criteria such as a negative change, a large change to the positive side, and a large difference between the X side and the Y side. Specifically, the allowable time during which finger contact determination continues to be output is 60 seconds. In the example of FIG. 1, the abnormal state detection unit 10 determines that the PET bottle 5 is in an abnormal state because the PET bottle 5 is placed on the detection electrodes 2 c and 2 h of the touch panel and the finger contact determination continues to occur for 60 seconds or more.

  Next, in ST6, the control unit 4 instructs the baseline update unit 8, and the baseline update unit 8 updates the baseline value in an abnormal state in which a finger, a plastic bottle, or the like continues to touch or touch the touch panel. If it is necessary to update the baseline value, the process proceeds to ST7. If not, the process returns to ST1. Here, since it is an abnormal state in which finger contact determination continues to occur beyond the allowable time due to contact with the plastic bottle 5, the process proceeds to ST7.

  Next, in ST7, the control unit 4 instructs the baseline update unit 8, and the baseline update unit 8 updates the baseline value by measuring the new baseline value = current baseline value × α + ST1. This is done by calculating the capacitance value × β. α and β are weighting parameters, and α + β = 1.0. In updating the baseline in the abnormal state, the capacitance value measured in ST1 is weighted, for example, β = 0.95.

  Next, proceeding to ST8, the control means 4 instructs the baseline storage means 9, and the baseline storage means 9 stores the new baseline value updated by the baseline update means 8. The stored baseline values are shown in FIG.

  Next, returning to ST1, the capacitance detection means 3 detects the capacitance values of the detection electrodes 2a to 2j in accordance with an instruction from the control means 4 at the next timing, and the processing of ST1 to ST8 is repeated.

  Next, the operation when the finger is not approaching any of the electrodes shown in FIG. 7 after the state shown in FIG. 1 continues for a while will be described.

  The control means 4 instructs the capacitance detection means 3 in ST1, and the capacitance detection means 3 sequentially detects the capacitance values of the detection electrodes 2a to 2j, and detects the detected capacitance values in proximity. Output to the contact detection means 7 and the baseline update means 8. FIG. 8 shows the capacitance values and the baseline values of the detection electrodes 2a to 2j in the example in which the state of FIG. 1 is changed to the state of FIG. Compared with the state in which the PET bottle 5 of FIG. 1 is placed, the detected capacitance value is small because no finger approaches or approaches any of the electrodes 2a to 2j. The baseline value is a baseline value updated by the baseline update means 8 shown in FIG. 6 in the state of FIG.

  Next, in ST2, the control means 4 instructs the proximity / contact detection means 7, and the proximity / contact detection means 7 determines the finger or the like based on the obtained capacitance values of the detection electrodes 2a to 2j. Proximity or contact status is detected. Here, in the example from the state of FIG. 1 to the state of FIG. 7, the state where the PET bottle 5 of FIG. 1 is placed is the baseline value, so that the finger approaches any of the detection electrodes 2a to 2j. In the state shown in FIG. 7, the difference value between the capacitance value and the baseline value of the detection electrodes 2a to 2j takes a negative value except for a part as shown in FIG.

  Next, the process proceeds to ST3, where the control means 4 instructs the proximity / contact detection means 7 to determine whether or not the finger is in proximity, ST4 if it is in proximity or contact, and ST5 otherwise. move on. Here, since the capacitance value of any of the detection electrodes 2a to 2j does not exceed the threshold value 20 for proximity of the finger, it is determined that the finger is not in proximity or in contact, and the process proceeds to ST5.

  Next, in ST5, the control unit 4 instructs the abnormal state detection unit 10, and the abnormal state detection unit 10 continues to issue a finger contact determination or may occur when the capacitance value is a finger (or derivative) contact. The presence / absence of an abnormal state is determined based on criteria such as a negative change, a large change to the positive side, and a large difference between the X side and the Y side. Specifically, an abnormal state is determined when a state in which the difference value (= capacitance value−baseline value) between the detection electrodes 2a to 2j is equal to or less than the abnormality determination threshold value 22 continues for several seconds. In the example shown in FIGS. 1 to 7, the abnormal state detection means 10 determines that the detection electrodes 2b, 2c, 2d, 2g, and 2h are equal to or lower than the abnormality determination threshold 22 as shown in FIG. Then, the process proceeds to ST6, ST7, ST8, and the baseline update means 8 updates the baseline and enters a normal state.

  Next, a case where the environment around the touch panel changes and the temperature rapidly increases will be described. The control means 4 instructs the capacitance detection means 3 in ST1, and the capacitance detection means 3 sequentially detects the capacitance values of the detection electrodes 2a to 2j, and detects the detected capacitance values in proximity. The data is output to the contact detection unit 7, the baseline update unit 8, and the abnormal state detection unit 10. FIG. 10 shows the capacitance value and the baseline value of the detection electrodes 2a to 2j in this example.

  Next, in ST2, the control unit 4 instructs the proximity / contact detection unit 7, and the proximity / contact detection unit 7 approaches the proximity of the finger based on the obtained capacitance values of the detection electrodes 2a to 2j. Alternatively, the contact state is detected. In this example, as shown in FIG. 11, the capacitance value obtained by subtracting the baseline value from the detected capacitance value is smaller than the threshold value 20 in the proximity state in any of the detection electrodes 2a to 2j. The capacitance value shows a value equal to or greater than a certain value 23 due to temperature rise.

  Next, the process proceeds to ST3, where the control means 4 instructs the proximity / contact detection means 7 to determine whether or not the finger is in proximity or contact, and if it is in proximity or contact, ST4, otherwise. Proceed to ST5. Here, since the differential capacitance values of any of the detection electrodes 2a to 2j do not exceed the proximity detection threshold value 20, it is determined that they are not in proximity or contact, and the process proceeds to ST5.

  Next, in ST5, the control unit 4 instructs the abnormal state detection unit 10 to continue the finger contact determination, or the capacitance value fluctuates to the minus side which cannot occur when the finger (or derivative) is touched. The presence / absence of an abnormal state is determined based on a determination criterion such as a large change in the whole to the plus side or a large difference between the X side and the Y side. Specifically, when a state where the minimum value of the difference value (= capacitance value−baseline value) between the detection electrodes 2a to 2j is equal to or less than the threshold value 20 continues for several seconds, it is determined as an abnormal state. Here, since the minimum value of the difference value (= capacitance value−baseline value) is equal to or less than the threshold value 20, the abnormal state detection unit 10 proceeds to ST6, ST7, ST8, and the baseline update unit 8 The value is updated to return to the normal state.

  Next, an operation when water droplets adhere to the touch panel surface as shown in FIG. 12 will be described. In FIG. 12, a frame 11 coated with an insulator is around the detection electrodes 2a to 2e in the X direction and the detection electrodes 2f to 2j in the Y direction, and water droplets 6 are formed on the detection electrodes 2e, 2g, 2h, 2i, and 2j. Adhering across. When the water droplet 6 is attached, the dielectric constant of water is higher than that of air, and capacitance is generated between the frame 11 adjacent to the detection electrodes 2e, 2g, 2h, 2i, and 2j. A capacitance value equivalent to the case of contact is output.

  13 is a partial cross-sectional view of the touch panel with a frame to which water droplets having the structure shown in FIG. In FIG. 13, the detection electrodes 2 d, 2 e, 2 j are installed below the glass surface 1, a frame 11 is installed on the glass surface 1, and the frame 11 includes a grounded metal part 12. In the state of FIG. 13, the capacitance generated between the detection electrodes 2d, 2e, 2j and the frame 11 hardly occurs because an air layer having a low dielectric constant exists between them.

  FIG. 14 is a partial cross-sectional view of the state in which water droplets 6 are attached to the frame-equipped touch panel shown in FIG. 12 as viewed from the front. In FIG. 14, the detection electrodes 2d, 2e, and 2j are installed below the glass surface 1, a frame 11 is installed on the glass surface 1, and the frame 11 is configured to include a grounded metal part 12. Water droplets 6 are attached on the detection electrodes 2e and 2j. In the state of FIG. 14, there are water droplets 6 between the detection electrodes 2 e and 2 j and the frame 11, and water has a dielectric constant approximately 80 times larger than that of air, and thus is generated between the detection electrodes 2 e and 2 j and the frame 11. A larger amount of capacitance is generated than in FIG.

  The control means 4 instructs the capacitance detection means 3 in ST1, and the capacitance detection means 3 sequentially detects the capacitance values of the detection electrodes 2a to 2j, and detects the detected capacitance values in proximity. Output to the contact detection means 7 and the baseline update means 8. FIG. 15 shows the capacitance values and the baseline values of the detection electrodes 2a to 2j in the example of FIG. Compared with the case where the water droplet 6 is not attached, a larger capacitance is generated, so the capacitance values of the detection electrodes 2e, 2g, 2h, 2i, and 2j that are close to each other via the frame 11 and the water droplet 6 are compared. Large value. In particular, since the detection electrode 2e has a large area in contact with the frame 11 via the water droplet 6, it takes a larger capacitance value.

  Next, in ST2, the control means 4 instructs the proximity / contact detection means 7, and the proximity / contact detection means 7 determines the finger or the like based on the obtained capacitance values of the detection electrodes 2a to 2j. Proximity or contact status is detected. In the example of the state shown in FIG. 12, as shown in FIG. 16, the difference value between the Y-side detection electrodes 2 f to 2 j does not exceed the proximity threshold 20, but the X-side detection electrodes 2 a to 2- Regarding the difference value 2e, the difference value of the detection electrode 2e exceeds the finger contact threshold value 21.

  Next, the process proceeds to ST3, where the control means 4 instructs the proximity / contact detection means 7 to determine whether or not the finger is in proximity, ST4 if it is in proximity or contact, and ST5 otherwise. move on. Here, since both the X and Y detection electrodes do not exceed the proximity / contact threshold value, the proximity / contact condition is not satisfied, and the process proceeds to ST5.

  Next, in ST5, the control unit 4 instructs the abnormal state detection unit 10, and the abnormal state detection unit 10 continues to issue a finger contact determination or occurs when the capacitance value is a finger (or derivative) contact. The presence / absence of an abnormal state is determined based on criteria such as negative fluctuation, large fluctuation toward the positive side, large fluctuation as a whole, and a large difference between the X side and the Y side. Specifically, an abnormal state is determined when a state where the difference between the maximum difference value on the X side and the maximum difference value on the Y side is equal to or greater than the threshold value 24 continues for several seconds. In the example of FIG. 14, the abnormal state detection means 10 determines that the maximum difference value on the Y side−the maximum difference value on the X side is equal to or greater than the threshold value 24 and proceeds to ST6, ST7, ST8, and updates the baseline. The means 8 updates the baseline value and becomes normal.

  As described above, according to the first embodiment, the abnormal state detection unit 10 is provided and the finger contact is continuously output. Or, if the capacitance value cannot occur with finger operation, calibration is performed and the baseline value is reset to enable automatic recovery, thus improving the safety and maintainability of the touch panel. Can do.

  Further, the abnormal state detection means 10 may determine the abnormal state of the distribution using the electrostatic capacitance distribution based on the abnormal state of the detection target of the finger or the stylus pen, and may change the allowable time for the finger contact output. . Specifically, when a finger or a stylus pen is in contact, the waveform is a steep mountain as shown in FIG. 17, and when a thing such as a plastic bottle or a mobile phone is in contact, the gentle waveform shown in FIG. Use the property of a mountain-like waveform. Here, as an example, kurtosis Xk shown in the following formula 1 is used as a scale for discriminating the distribution, and it is determined that the finger is in contact when Xk is equal to or greater than a certain value. Note that this capacitance distribution may vary depending on the size of the operator's finger, the size of the detection electrodes, the pitch between the detection electrodes, and the layout method, and is set for each condition. Here, the range of kurtosis when a finger or a stylus pen touches is 2.0 <Xk. When the kurtosis is 2.0 or less, the abnormal state detection means 10 determines that the waveform is not a finger contact, and shortens the time until the abnormal state is determined.

  Also, the update method of the baseline value at the time of calibration is (new baseline value = current baseline value × α + capacitance value measured by ST1 × β). Interpolation with adjacent detection electrodes may be added.

  Moreover, although the update method of the baseline value in each abnormal state is the same, a different update method may be used for each.

  The touch panel device according to the present invention determines an abnormal state that cannot normally occur by a finger operation and can automatically return to a normal state, thereby improving operability and changing capacitance. It is useful for all electrical equipment having a touch panel for performing switch input.

  DESCRIPTION OF SYMBOLS 1; Glass surface, 2a-2j; Detection electrode, 3; Capacitance detection means, 4; Control means, 6: Water droplet, 7; Proximity / contact detection means, 8; Baseline update means, 9; 10: Abnormal state detection means, 11: Frame.

Claims (4)

A plurality of detection electrodes whose capacitance changes due to the contact and proximity of the detection object;
A capacitance detecting means for detecting a capacitance between the detection electrode and the detection object;
Baseline storage means for storing a baseline value which is a capacitance value serving as a reference for detecting the proximity or contact of the detection object;
A proximity-contact detection means to determine the state of the proximity or contact touch of the resultant capacitance value and the detection object by the baseline value by the capacitance detecting means,
Baseline update means for updating the baseline value of the baseline storage means with the capacitance value and the baseline value obtained by the capacitance detection means;
Abnormalities of each detection electrode that cannot occur by operation of the detection object from the state of the detection object detected by the proximity / contact detection means, the baseline value of the plurality of detection electrodes, and the capacitance value distribution of the plurality of detection electrodes An abnormal state detecting means for detecting a state;
Comprising control means for controlling each means,
The control means controls the baseline update means to update the baseline value of the baseline storage means when the abnormal condition detection means determines that it is an abnormal condition ,
A touch panel device characterized in that the abnormal state detection means determines that the distribution of the difference value obtained from the baseline value and the capacitance value is an abnormal state when the distribution of the difference value is obtained in a direction opposite to that when the finger is touched . A plurality of detection electrodes whose capacitance changes due to the contact and proximity of the detection object;
A capacitance detecting means for detecting a capacitance between the detection electrode and the detection object;
Baseline storage means for storing a baseline value which is a capacitance value serving as a reference for detecting the proximity or contact of the detection object;
A proximity-contact detection means to determine the state of the proximity or contact touch of the resultant capacitance value and the detection object by the baseline value by the capacitance detecting means,
Baseline update means for updating the baseline value of the baseline storage means with the capacitance value and the baseline value obtained by the capacitance detection means;
Abnormalities of each detection electrode that cannot occur by operation of the detection object from the state of the detection object detected by the proximity / contact detection means, the baseline value of the plurality of detection electrodes, and the capacitance value distribution of the plurality of detection electrodes An abnormal state detecting means for detecting a state;
Comprising control means for controlling each means,
The control means controls the baseline update means to update the baseline value of the baseline storage means when the abnormal condition detection means determines that it is an abnormal condition ,
The touch panel device , wherein the abnormal state detection means determines that the abnormal state is detected when the entire distribution of the difference values obtained from the baseline value and the capacitance value becomes a certain value or more . A plurality of detection electrodes whose capacitance changes due to the contact and proximity of the detection object;
A capacitance detecting means for detecting a capacitance between the detection electrode and the detection object;
Baseline storage means for storing a baseline value which is a capacitance value serving as a reference for detecting the proximity or contact of the detection object;
A proximity-contact detection means to determine the state of the proximity or contact touch of the resultant capacitance value and the detection object by the baseline value by the capacitance detecting means,
Baseline update means for updating the baseline value of the baseline storage means with the capacitance value and the baseline value obtained by the capacitance detection means;
Abnormalities of each detection electrode that cannot occur by operation of the detection object from the state of the detection object detected by the proximity / contact detection means, the baseline value of the plurality of detection electrodes, and the capacitance value distribution of the plurality of detection electrodes An abnormal state detecting means for detecting a state;
Comprising control means for controlling each means,
The control means controls the baseline update means to update the baseline value of the baseline storage means when the abnormal condition detection means determines that it is an abnormal condition ,
The detection electrodes are provided in a plurality of different directions, and the abnormal state detection means is a distribution of difference values obtained from the baseline value and the capacitance value, and the difference in the capacitance values in the detection electrodes in a plurality of different directions is a constant value. A touch panel device that is judged to be in an abnormal state in the above case . A plurality of detection electrodes whose capacitance changes due to the contact and proximity of the detection object;
A capacitance detecting means for detecting a capacitance between the detection electrode and the detection object;
Baseline storage means for storing a baseline value which is a capacitance value serving as a reference for detecting the proximity or contact of the detection object;
A proximity-contact detection means to determine the state of the proximity or contact touch of the resultant capacitance value and the detection object by the baseline value by the capacitance detecting means,
Baseline update means for updating the baseline value of the baseline storage means with the capacitance value and the baseline value obtained by the capacitance detection means;
Abnormalities of each detection electrode that cannot occur by operation of the detection object from the state of the detection object detected by the proximity / contact detection means, the baseline value of the plurality of detection electrodes, and the capacitance value distribution of the plurality of detection electrodes An abnormal state detecting means for detecting a state;
Comprising control means for controlling each means,
The control means controls the baseline update means to update the baseline value of the baseline storage means when the abnormal condition detection means determines that it is an abnormal condition ,
When the abnormal state detection means determines that the contact is made with a finger or a stylus pen from the distribution shape of the difference value obtained from the baseline value and the capacitance value, and when the contact is determined to be contact with an object other than the finger or the stylus pen Thus, the touch panel device is characterized in that the abnormal state is determined when the time for determining the abnormal state is changed and the proximity or the contact is continuously determined for the respective time or longer .

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