CN1797308A - Interpretation method of touch sensing device - Google Patents

Abstract

The invention relates to an interpretation method of a touch sensing device, wherein the touch sensing device comprises a touch Pad , the touch Pad is at least connected with mxn equivalent capacitors, m is the equivalent capacitor number in the X-axis direction, and n is the equivalent capacitor number in the Y-axis direction, the interpretation method comprises the following steps: charging m equivalent capacitors of one row in the X-axis direction to obtain m digital signals; comparing the m digital signals, and using the minimum one as a potential reference value; repeating the first two steps to obtain n potential reference values of all equivalent capacitors; touching the touch pad; scanning the touch pad to obtain at least one potential variation value of m equivalent capacitors corresponding to at least one row; and comparing the potential reference value with the potential variation value to judge which point in the row on the touch pad is touched.

Description

Interpretation method of touch sensing device

technical field

The invention refers to a method for interpreting a touch sensing device, in particular to a method for interpreting a capacitive touch sensing device.

Background technique

General touch sensing devices can be divided into resistive and capacitive in terms of system design. Taking the commonly used capacitive touch sensing devices as an example, there are currently three detection methods in use, which are briefly described as follows:

(1) Record the potential of one of the touch buttons and compare it with the charging potential of all the buttons. The microcontroller will finally know which button is pressed:

First, the microcontroller will enter the stage of storing the potential reference value, and the system will send a continuous pulse wave to the equivalent capacitance of the touch panel, and a charge energy will be induced at the other end of the capacitor, and the charge will be stored in the capacitor through the integrator In the process, the charging potential of the capacitor is amplified by the amplifier, and finally converted into a digital signal by the analog/digital conversion circuit and stored in the memory; then enters the button scanning stage, which is the simulation of each button on the touch panel / The digital output signal is compared with the signal in the memory, and when it is lower than the signal in the memory, it means that the button has been touched.

The disadvantage of this method is that if the thickness of the board and the copper foil are different or uneven during the production process, the capacitance value of the equivalent capacitance of each button will also be uneven, and it is easier to produce a comparison. error.

(2) Compare the value obtained by averaging the charging potentials of all buttons with the charging potentials of all buttons, and the microcontroller finally knows which button is pressed:

When entering the storage potential reference value stage, the potential values of the equivalent capacitors of all buttons are averaged and then stored in the memory, and then enter the button scanning stage, and compare the potential values of the integral capacitors of all buttons with the reference potential value. If the key potential value is lower than the reference potential value, it indicates that a key is pressed.

(3) Record the charging potentials of all buttons and then compare them individually. If the comparison result is lower than the previously recorded button potential value, the microcontroller will know which button is pressed:

In the stage of storing the potential reference value, the integral capacitor potential values of all buttons are stored. After entering the button scanning stage, the integrated capacitor potential value of each scanned button is compared with the reference integral capacitor potential value of the button. If scanning When the button mode potential is lower than the reference integral capacitor potential value, it means that a button is pressed.

Among the above three methods, although the memory space used by the first and second methods is very low, the sensing range and sensitivity will become very poor with the increase of touch keys; The equivalent capacitance of the button will vary with the uniformity of the board, board thickness, and copper thickness, which will seriously affect the uniformity of the equivalent capacitance, resulting in differences in the potential charged by the equivalent capacitance of each button, so if Compared with the previously recorded potential, misjudgment often occurs, and it is also more susceptible to interference from external factors.

Although the third method can effectively improve the sensing range and sensitivity of the touch sensing device, if it is used in a large number of keys (for example: hundreds of keys), it will obviously take up more space on the memory, here At the same time, if the bits of the analog/digital circuit in the touch sensing device are higher, the memory space occupied by it will be larger, and the addition and multiplication of the two makes the processing speed of the whole device slower and the calculation speed lower.

Contents of the invention

The main purpose of the present invention is to improve the detection range and sensitivity of the capacitive touch sensing device.

Another object of the present invention is to reduce the space used by the memory, increase the processing speed of the microcontroller, and greatly increase the sensing range and sensitivity of the touch by obtaining the lowest integrated capacitance potential on the X-axis in the matrix.

The main idea of the present invention is to compare all the points on the X-axis of each row when storing the potential reference value, and after the comparison, take the lowest key potential value and store it in the memory. When entering the key scanning stage, the X The key potential of each row of the axis is compared with the potential reference value of the row. When the potential value is lower than the reference value, it can be determined that a key is pressed.

According to the main idea of the present invention, a method for interpreting a touch sensing device is proposed, a method for interpreting a touch sensing device, wherein the touch sensing device includes a touch panel (Pad), and the touch panel is at least connected to m × n equivalent capacitances, m is the number of equivalent capacitances on the X-axis direction, and n is the number of equivalent capacitances on the Y-axis direction. The interpretation method includes the following steps: (a) for one column of m in the X-axis direction The equivalent capacitors are charged to obtain m digital signals; (b) compare the m digital signals, and use the smallest one as a potential reference value; (c) repeat steps (a)-(b) to obtain n reference potential values of all equivalent capacitances; (d) touching the touch panel; (e) scanning the touch panel to obtain at least one potential change value relative to the m equivalent capacitances in at least one column and (f) comparing the potential reference value with the potential change value to judge which point in the column on the touch panel is touched.

According to the main idea of the present invention, a method for interpreting a touch sensing device is proposed, wherein the touch sensing device includes m×n keys, and each of the keys is connected to a capacitor, and m is the number of keys in the X-axis direction , n is the number of keys on the Y-axis direction, and the interpretation method includes the following steps: (a) charge m capacitors in one column in the X-axis direction to obtain m digital signals; (b) compare the m digital signals signal, and wherein the smallest one is used as a potential reference value; (c) repeat steps (a)-(b) to obtain n such potential reference values of all capacitors; (d) touch the touch panel; (e ) scanning the touch panel to obtain at least one potential variation value of m capacitors in at least one column; and (f) comparing the potential reference value with the potential variation value to judge the potential variation value in the column on the touch panel which point is touched.

The present invention can be better understood by the following drawings and detailed description:

Description of drawings

1 is a schematic structural view of a capacitive touch sensing device of the present invention;

FIG. 2 is a schematic diagram of the interpretation method of the capacitive touch sensing device of the present invention.

Detailed ways

The principle adopted in the present invention is that firstly, the charging potential value of a certain button on each X-axis must be stored as the potential reference value, and the integral capacitance potential value of this button must be the lowest on the coaxial axis, so as to provide the charging potential value of each button. Comparing the charging potential, when a hand touches the charge energy on the button will be attracted by the finger, and at this time the charging potential of the button must be lower than the potential reference value of the original button, at this time the microcontroller can judge that the button is At that point the key was pressed.

Now illustrate with the structural diagram and the schematic diagram of the embodiment of the present invention of Fig. 1 and Fig. 2:

Please refer to FIG. 1, which is a schematic structural diagram of a capacitive touch sensing device of the present invention. As shown in the figure, the touch sensing device of the present invention can be composed of a touch panel (Pad) (connected to m×n equivalent capacitors) Or m×n buttons, where m is the number of capacitors or equivalent capacitors in the X-axis direction, and n is the number of capacitors or equivalent capacitors in the Y-axis direction

In the process of microcontroller control system action, it can be roughly divided into two stages: (1) storing potential reference value and (2) key scanning;

(1) Storage potential reference value stage

a. First output a first continuous pulse wave from the output terminal of the microcontroller to m capacitors or equivalent capacitors in one column.

b. After passing through the equivalent capacitance or the capacitance of the button, the first pulse wave will induce a first energy from the other end, and store it in the integrator.

c. Inputting a first waveform output by the integrator to the operational amplifier for signal amplification.

d. After the output of the operational amplifier is converted into a first digital signal by the analog/digital conversion circuit, the value will be stored in the memory.

e. Continue scanning until the integrated capacitor potentials of all keys on the column (X-axis) are converted into the first digital signal, and then store it in the memory.

f. Finally, compare the digital signals of all keys on the same column (X axis), and save the one with the lowest potential and store it in the memory.

g. Multiply this value by a certain ratio (such as 95% or 90%; multiplying a certain ratio here is to freely control the sensitivity; if the ratio is set lower, the touch The sensitivity will decrease; if the setting is too high, the microcontroller may misjudgment due to a little interference, so it can be adjusted according to the mechanism of the external electrical appliance to achieve the best touch range) After that, It is then stored in the random access memory as a potential reference value for subsequent scanning of each point, and finally the first energy of the button on the integrator is cleared.

h. After storing the potential reference values of the capacitors in each column (X-axis) in the memory (as shown in Figure 2), you can enter the next button scanning stage and wait for the user to touch the button or touchpad .

(2) Key scanning stage

When the user touches the button or the touchpad, it enters the button scanning stage. After scanning each button, it will also go through the processing procedures of the integrator, operational amplifier and analog/digital conversion circuit, and the action starts with the storage potential Steps a to c of the baseline value stage are the same;

i. First output a second continuous pulse wave to the m equivalent capacitors or capacitors in the row from the output terminal of the microcontroller.

j. After passing through the equivalent capacitance or the capacitance of the button, the second pulse wave will induce a second energy from the other end and store it in the integrator.

k. Inputting a second waveform output by the integrator into an operational amplifier for signal amplification.

l. After the output of the operational amplifier is converted into a second digital signal by the analog/digital conversion circuit, the second digital signal is the potential change value of the button or the touch panel after being touched by the user.

m. Compare the potential change value with the potential reference value in the memory; when the potential change value is lower than the potential reference value, it means that someone has touched the button or touch panel, and the microcontroller sends the coordinate value, And continue to scan the next column (X axis). On the contrary, if the potential change value of the button or touch panel is greater than or equal to the potential reference value, it means that no one touches the button, and the microcontroller ignores it and continues Scan the next column (X axis).

It is worth mentioning that the memory used to implement the present invention can be a random access memory, and if the system is powered off or the reset switch is activated, the microcontroller must recalculate and store the potential reference value.

Although the microcontroller in the above-mentioned embodiment realizes the object of the present invention by setting it separately from the memory and the integrator, it is also possible to integrate the memory and the integrator into the microcontroller to achieve the invention of the present invention in actual production. Purpose.

To sum up, the detection method of the touch sensing device of the present invention can greatly increase the sensing range and sensitivity of the capacitive touch sensing device, and at the same time, various flexible adjustments can be made on the type and quantity of the touch keys. The design and various changes will not be affected by the imperfection of the electrical properties of the external components or the unevenness of the equivalent capacitance of the touch panel.

Claims (10)

1. A method for interpreting a touch sensing device, wherein the touch sensing device includes a touch panel, and the touch panel is at least connected to mxn equivalent capacitors, where m is the number of equivalent capacitors in the X-axis direction, n is the number of equivalent capacitances in the Y-axis direction, and the interpretation method includes the following steps: (a) Charge the m equivalent capacitors in one column in the X-axis direction to obtain m digital signals; (b) comparing the m digital signals, and using the smallest one as a potential reference value; (c) Steps (a)-(b) are repeated to obtain n reference values of this potential of all equivalent capacitances; (d) touch the touchpad; (e) scanning the touch panel to obtain at least one potential change value relative to the m equivalent capacitances in at least one row; and (f) Comparing the potential reference value and the potential variation value to judge which point in the row on the touch panel is touched. 2. The interpretation method according to claim 1, wherein the touch sensing device further comprises an integrator and a memory, and the step (a) further comprises the following steps: (a1) providing a first pulse wave to the m equivalent capacitors to induce a first energy; (a2) storing the first energy into the integrator; (a3) amplifying and converting a first output waveform of the integrator into the first digital signal; and (a4) storing the first digital signal into the memory, wherein the memory can be a random access memory. 3. The interpretation method according to claim 1, characterized in that step (b) is to multiply the smallest first digital signal by a proportional number to become the potential reference value, and store the potential reference value into the memory , wherein the ratio can be specified by the user to freely adjust the level of touch sensitivity. 4. The interpretation method as claimed in claim 1, wherein step (b) further comprises a step of clearing the first energy in the integrator. 5. The interpretation method as claimed in claim 1, characterized in that steps (d) and (e) also include steps as follows: (d1) providing a second pulse wave to the m equivalent capacitors to induce a second energy; (d2) storing the second energy into the integrator; and (d3) amplifying and converting a second output waveform of the integrator into a second digital signal, and the second digital signal is the potential variation value. 6. The interpretation method according to any one of claims 1-5, characterized in that: The touch sensing devices all include a microcontroller for controlling each step; and/or The memory and the integrator included in the touch sensing device are integrated in a microcontroller. 7. An interpretation method of a touch sensing device, wherein the touch sensing device includes a touch panel, and the touch panel is at least connected to a plurality of equivalent capacitors, the interpretation method comprising the following steps: (a) charging each equivalent capacitance to obtain at least one digital signal; (b) comparing each of the digital signals, and using the smallest one as a potential reference value; (c) touch the touchpad; (d) scanning the touch panel to obtain at least one potential variation value of each equivalent capacitance; and (e) Comparing the potential reference value with each of the potential variation values to determine which point on the touch panel is touched. 8. A method for interpreting a touch sensing device, wherein the touch sensing device includes mxn keys, and each of the keys is connected to a capacitor, m is the number of keys on the X-axis direction, and n is the number of keys on the Y-axis direction The number of keys, the interpretation method includes the following steps: (a) Charge m capacitors in one column in the X-axis direction to obtain m digital signals; (b) comparing the m digital signals, and using the smallest one as a potential reference value; (c) repeat steps (a)-(b), to obtain n this potential reference value of all electric capacity; (d) touch the touchpad; (e) scanning the touch panel to obtain at least one potential change value relative to the m capacitors in at least one row; and (f) Comparing the potential reference value and the potential variation value to judge which point in the row on the touch panel is touched. 9. A method for interpreting a touch sensing device, wherein the touch sensing device includes at least one key, and each of the keys is connected to a capacitor, the interpreting method comprising the following steps: (a) charging each of the capacitors to obtain at least one digital signal; (b) comparing each of the digital signals and using the one characterized by the smallest value as a potential reference value; (c) touch the touchpad; (d) scanning the touch panel to obtain at least one potential variation value of each of the capacitors; and (e) Comparing the potential reference value with each of the potential variation values to determine which point on the touch panel is touched. 10. The interpretation method according to claim 9, wherein the touch sensing device further comprises an integrator and a memory, and the step (a) further comprises the following steps: (a1) providing a first pulse wave to each of the capacitors to induce a first energy; (a2) storing the first energy into the integrator; (a3) amplifying and converting a first output waveform of the integrator into the first digital signal; and (a4) storing the first digital signal into the memory.

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