JPH0934641A - Detector for touch panel press position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a high-precision press position regardless of superposition of noise by converting the voltage outputted from a touch panel to a digital value and eliminating abnormal data. SOLUTION: A press detection part 11 detects whether the touch panel is pressed or not. A data recording part 12 reads in X-axis data outputted from an A/D converter 5 through an I/O 18 to record it in a memory. A switch control part 15 opens switches 2-1 and 2-2 and closes switches 3-1 and 3-2 through an I/O 17. The data recording part 12 reads in Y-axis data, which is outputted from an operational amplifier 4-2 and is subjected to A/D conversion, through an I/O 18 and records it in the memory. An abnormal data elimination part 13 eliminates abnormal data from X-axis data and Y-axis data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch panel pressed position detecting device for detecting the pressed position of a touch panel.

[0002]

2. Description of the Related Art As one of the input methods of today's electronic equipment, a method of inputting from a touch panel provided on a display screen is used. FIG. 3 shows a specific example of the touch panel, which is displayed on the display surface of a liquid crystal display device, a CRT, or the like.
For example, a transparent conductive thin film made of an indium-tin oxide film (i
TD films), and the electrodes XL and XR are provided at the left and right ends of the upper film, and the electrode Y is provided at the upper and lower ends of the lower film.
U and YL are attached.

As shown in FIG. 4, the pressing position is detected by X
In the axial position detection, the left electrode XL on the upper surface is grounded and a bias voltage is applied to the right electrode XR. When the touch panel is pressed, the iDT film on the upper surface comes into contact with the iDT film on the lower surface at a pressing point. Therefore, V _xk = k · V _B (1) where V _{B is the} bias voltage k = R ₁ / (R ₁ + R ₂ ) = X _P / X _W (2) ) X _W: length between XL and XR, X _P: voltage V _xk consisting length to pressing point than XL is output.

In the equation (1), since V _B is known, k can be known. Since k is represented by the equation (2), the pressing point X _P of the X axis can be obtained. Also, Y
Also in the axial direction, the pressing point Y _P can be obtained in the same manner as the X-axis direction.

[0005]

As described above, in the detection of the pressing position of the conventional touch panel, a bias voltage is applied to one iTD film of the touch panel to make a contact by pressing, and the iTD film of the other touch panel is exposed. The pressing position is obtained by the voltage value.

The touch panel is installed on the display surface of a display device such as an LCD or CRT. Therefore, the noise induced from the display device is superimposed on the output voltage of the touch panel. That is, for example, a dot graphic LCD has X
A scanning voltage is sequentially applied to the shaft electrodes and a signal voltage is applied to the Y-axis electrodes for display. However, in this case, a high voltage of about 30 V is intermittently applied, and this intermittent high voltage is applied. A voltage (pulse) is induced in the touch panel and becomes noise.

When noise is superimposed on the touch panel, the pressing position changes greatly, which causes a position error. An object of the present invention is to provide a touch panel pressed position detection device capable of detecting a pressed position with high accuracy even when noise is superimposed.

[0008]

Means adopted by the present invention to solve the above-mentioned problems will be described. According to a first aspect of the present invention, in a touch panel pressed position detection device for detecting a pressed position of a touch panel, an analog-digital conversion means for converting X-axis and Y-axis voltages output from the touch panel into digital values, and the touch panel pressed. Data recording means for recording a plurality of pieces of X-axis data and Y-axis data output from the analog-to-digital conversion means, and X-axis data and Y-axis data recorded in the data recording means. Abnormal data deleting means for deleting abnormal data from the inside, and X-axis data and Y data from the remaining data deleted by the abnormal data deleting means and recorded in the data recording means.
And a pressing position calculating means for calculating an average value of the axis data and calculating and outputting the pressing position.

The analog-digital conversion means converts the X-axis and Y-axis voltages output from the touch panel into digital values. The data recording means records a plurality of pieces of X-axis data and Y-axis data output from the analog-digital conversion means while the touch panel is being pressed.

The abnormal data deleting means deletes the abnormal data from the X-axis data and the Y-axis data recorded in the data recording means. The pressing position calculating means calculates the pressing position by calculating the average value of the X axis data and the Y axis data from the remaining data deleted by the abnormal data deleting means and recorded in the data recording means, and outputs the calculated pressing position.

Further, in the second invention, the determination of the abnormal data made by the abnormal data deleting means is performed by sequentially reading the data for each of the X-axis and Y-axis data recorded in the data recording means. , If the difference between the previously read data value and the currently read data value is greater than or equal to the set value, it is determined to be abnormal and the previously read data or both data are deleted.

Further, in the third invention, the determination of abnormal data made by the abnormal data deleting means is performed by averaging the data for each of the X-axis and Y-axis data recorded in the data recording means. When the difference between the obtained average value and the recorded data value is equal to or more than the set value, it is determined to be abnormal and the data is deleted.

Further, in the fourth invention, the determination of the abnormal data determined by the abnormal data deleting means is performed by averaging the data for each of the X-axis and Y-axis data recorded in the data recording means. The standard deviation is obtained, and when the difference between the obtained average value and the recorded data value is A · standard deviation (A is a set value) or more, it is determined to be abnormal and the data is deleted.

Further, in the fifth invention, the data to be deleted by the abnormal data deleting means is sequentially read out for each of the X-axis and Y-axis data recorded in the data recording means, and the data is read from the previous time. If the difference between the data values read this time is greater than or equal to the set value, the previous or both data are deleted, the average value is calculated for the remaining data, and the difference between the calculated average value and the remaining data value is Delete the data that exceeds the set value.

Further, in the sixth invention, the data to be deleted by the abnormal data deleting means is sequentially read out for each of the X-axis and Y-axis data recorded in the data recording means, and the data is read from the previous time. If the difference between the data values read this time is greater than or equal to the set value, the previous or both data are deleted, and the standard deviation of the average value is calculated for the remaining data, and the calculated average value and the remaining data value are Difference is A
・ Delete the data that exceeds the standard deviation (A is the set value).

As described above, the voltage output from the touch panel is converted into a digital value, and among the plurality of converted digital values, a value equal to or more than the set value and a value set to the difference from the average value. Since the data other than the above or the deviation value other than the set deviation value is deleted and the pressed position is calculated from the remaining data, even if noise is superimposed on the voltage output from the touch panel, noise is superimposed. The removed data is removed, and the pressed position can be detected with high accuracy.

Further, since the data having a difference in deletion of data equal to or larger than the set value is deleted, and further the data having a difference from the average value with respect to the remaining data or larger is deleted, Even if both the impulsive noise whose average value does not become 0 and the noise whose average value becomes 0 are superimposed, it is possible to detect the pressed position with high accuracy.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of an embodiment,
FIG. 2 is an operation flowchart of the same embodiment. FIG.
1, 1 is the touch panel described in FIG. 3, 2 and 3 are switches, 4 is an operational amplifier, 5 is an analog-digital converter (A / D), 11 is a pressure detection unit, 12 is a data recording unit, and 13 is abnormal data deletion. Section, 14 is a pressed position calculation section, 15 is a switch control section, 16 to 19 are interfaces (I / O), and 20 is a processor (CPU) that performs processing.
It is.

Before the pressing position detection is started, the switch 2-1
And 2-2 are closed and the bias voltage is applied, and the switches 3-1 and 3-2 are open. Also, since it is not pressed, P
There is no contact of the iTD film at the point indicated by, and the operational amplifier 4-1
Is 0.

Next, the operation will be described with reference to FIG. In process S1, the press detection unit 11 detects whether or not the touch panel is pressed. As for the detection of whether or not it is pressed, as described above, the output of the operational amplifier 4-1 is 0 when it is not pressed, but when it is pressed, a value of 0 or less is output. Therefore, when the X-axis data value (output of the operational amplifier 4-1) output from the A / D 5 is other than 0, it is determined that it has been pressed, and when it is determined that it has not been pressed, it waits until it is pressed. .

In the process S2, the data recording unit 12 displays A /
The X-axis data V _X output from D5 is read via the I / O 18 and recorded in a memory (not shown). Then process S
In step S3, it is determined whether or not the number recorded is N. If the number is not N, the process proceeds to step S2 after a certain time to read and record the next X-axis data.

In step S4, the switch control unit 15 causes the I
Open switches 2-1 and 2-2 via / O2,
Also, the switches 3-1 and 3-2 are closed via the I / O 17. In process S5, the data recording unit 12 reads the A / D converted Y-axis data V _Y output from the operational amplifier 4-2 via the I / O 18 and records it in a memory (not shown), and then proceeds to process S6. Then, it is determined whether or not the number of recorded data is N, and if the determination is NO, the process moves to step S5 to read and record the next data.

In step S7, the abnormal data deleting unit 13
The abnormal data is deleted from the X-axis data recorded in the process S2 and the Y-axis data recorded in the process S5. To determine abnormal data, the recorded data is read out sequentially and the i-th
If the X-axis data read at the th and the (i + 1) th is V _Xi and V _{Xi + 1} , then | V _Xi −V _{Xi + 1} |> V _D (3) However, V _D is a set value. If there is, it is determined to be abnormal, and V _Xi or both V _Xi and V _{Xi + 1} data is deleted from the record. Similarly, the abnormal data is deleted for the Y-axis data.

In process S8, the pressed position calculation unit 14 calculates V _Xk = (from the M data remaining after being deleted in process S7 from the N data recorded in the memory (not shown) of the data recording unit 12. V _x1 + V _X2 + ... + V _XM ) / M (4) to obtain the average value V _Xk , and Xk = V _Xk / V _B (5) to perform the X-axis Find the pressed position Xk of I / O1
Output via 9.

Similarly, with respect to the Y axis, the calculation of V _YK = (V _Y1 + V _Y2 + ... + V _YJ ) / J (6) is performed from the J data remaining in the memory (not shown). the calculated average value V _YK performed, determine the touched position Y _K Y-axis performed _{Y K = V YK / V B} ··· (7) becomes operational, I / O1
Output via 9.

In step S9, the pressure detector 11 determines whether the Y-axis data value output from the operational amplifier 4-2 and A / D converted has become 0, that is, whether the pressure has been released. If the determination is NO, the process waits until YES. In process S10, the switch controller 15 performs the process S
When the determination result in 9 is YES, the switches 3-1 and 3-2 are opened via the I / O 17, and the switches 2-1 and 2-2 are closed via the I / O 16 and the process S1 is performed. Prepare for the next pressing position detection.

In the embodiment, the abnormal data is judged by the formula (3), but the calculation of V _a = (V ₁ + V ₂ + ... + V _N ) / N (8) is performed. To obtain the average V _a , and calculate the i-th data V
_{For i} , if | V _i −V _a |> V _D (9), it may be determined as abnormal and the data V _i may be deleted.

That is, the determination by the equation (3) is effective when the average value of noise does not become 0, but abnormal when both noises of the same polarity are superimposed on V _i and V _{i + 1.} For noise which is not judged and whose average value is 0, abnormal data can be surely deleted by judging from the difference from the average value.

Further, the determination of abnormal data is performed by σ = {(V ₁ ² + V ₂ ² + ... + V _N ² ) / N−V _a ² } ^0.5 (10) where V _a is expressed by the equation (8). Then, the standard deviation σ is obtained by performing the average calculation obtained in step S1, and for the i-th data V _i , | V _i −V _a |> A · σ (11) where A is a set constant. Is judged to be abnormal,
The data V _i may be deleted.

Further, first, the data is deleted by making a judgment by the formula (3), and the remaining data is judged by the formula (9) or the formula (11) and the data is deleted. With respect to Equation (4) and Equation (6)
May be performed. By deleting the two-stage circuit in this way, it is possible to delete the data on which the impulsive noise whose average value is not 0 and the noise whose average value is 0 are superimposed.

[0031]

As described above, according to the present invention, the following effects can be obtained. The voltage output from the touch panel is converted into a digital value, and among the converted digital values, the difference is greater than or equal to the set value, the difference from the average value is greater than or equal to the set value, or the set deviation value. Since the data other than that is deleted and the pressed position is calculated from the remaining data, even if noise is superimposed on the voltage output from the touch panel, the data on which noise is superimposed is removed, and A high pressed position can be detected.

Further, since the data having the difference of deletion of data is equal to or more than the set value, and the data having the difference from the average value with respect to the remaining data is equal to or more than the set value is deleted. Even if both the impulsive noise whose average value does not become 0 and the noise whose average value becomes 0 are superimposed, it is possible to detect the pressed position with high accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an operation flowchart of the embodiment.

FIG. 3 is a specific example of a touch panel.

FIG. 4 is a diagram illustrating a voltage output from a touch panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Touch panel 2, 3 switch 4 Operational amplifier 5 Analog-digital converter (A / D) 11 Press detection part 12 Data recording part 13 Abnormal data deletion part 14 Pressed position calculation part 15 Switch control part 16-19 Interface (I / O) 20 Processor (CPU)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Moriya 1-Chome, 1-Chiyomizu, Tottori City, Tottori Prefecture Aisin Chiyo Building Ricoh Tottori Technology Development Co., Ltd.

Claims (6)

[Claims] 1. A touch panel pressed position detection device for detecting a pressed position of a touch panel, wherein analog-digital conversion means for converting X-axis and Y-axis voltages output from the touch panel into digital values, and the touch panel is pressed. Data recording means for recording a plurality of pieces of each of X-axis data and Y-axis data output from the analog-to-digital conversion means in between, and abnormal among the X-axis data and Y-axis data recorded in the data recording means. Abnormal data deleting means for deleting data, and an average value of X-axis data and Y-axis data is calculated from the remaining data deleted by the abnormal data deleting means and recorded in the data recording means to calculate a pressing position. Pressing position calculating means for outputting Detection device. 2. The abnormal data judgment made by the abnormal data deleting means is sequentially read out for each of the X-axis and Y-axis data recorded in the data recording means, and the previously read data and this time are read. 2. The touch panel pressing position detecting device according to claim 1, wherein when the difference between the read data values is equal to or larger than a set value, it is determined to be abnormal and the previously read data or both data is deleted. 3. The determination of abnormal data made by the abnormal data deleting means is performed by averaging the data for each of the X-axis and Y-axis data recorded in the data recording means, and calculating the average value. 2. The touch panel pressing position detecting device according to claim 1, wherein when the difference from the recorded data value is equal to or more than a set value, it is determined as abnormal and the data is deleted. 4. The determination of abnormal data determined by the abnormal data deleting means is performed by obtaining an average and standard deviation of data for each of the X-axis and Y-axis data recorded in the data recording means. The data is deleted when the difference between the average value and the recorded data value is equal to or larger than A · standard deviation (A is a set value), and the data is deleted. Touch panel pressing position detection device. 5. The data to be deleted by the abnormal data deleting means is sequentially read for each of the X-axis and Y-axis data recorded in the data recording means, and the difference between the data values read last time and this time is read. If is greater than or equal to the set value, the previous or both data are deleted, the average value is calculated for the remaining data, and the difference between the calculated average value and the remaining data value is greater than or equal to the set value. The touch panel pressed position detection device according to claim 1, wherein the data is deleted. 6. The data to be deleted by the abnormal data deleting means is sequentially read for each of the X-axis and Y-axis data recorded in the data recording means, and the difference between the data values read last time and this time is read. If is greater than or equal to the set value, the previous or both data are deleted, the standard deviation of the average value is calculated for the remaining data, and the difference between the calculated average value and the remaining data value is A standard deviation. 2. The touch panel pressed position detection device according to claim 1, wherein data having a value (A is a set value) or more is deleted.