TWI496060B - Capacitive touch panel and its positioning method for two - dimensional application with single layer sensor - Google Patents

Description

Capacitive touch panel for realizing two-dimensional application by single-layer inductor and positioning method thereof

The present invention relates to a capacitive touch panel, and more particularly to a capacitive touch panel using a single layer inductor.

In two-dimensional applications, in order to provide accurate touch sensing, the capacitive touch panel must have good two-dimensional coordinate positioning capability, so the existing capacitive touch panels use a double-layer sensor architecture. As shown in FIG. 1, the capacitive touch panel of the double-layer inductor includes two layers of sensors in different directions overlapping each other. For convenience of explanation, the two layers of sensors are referred to as a first direction sensor and a second direction sensor, respectively. Each of the first direction sensors is coupled to the controller 12 via a scan line 14 for transmitting its capacitive sensing amount to the controller 12, as is the second direction sensor (not shown). The controller 12 knows the distribution of the capacitance sensing amount by scanning the scanning lines of the first direction sensor and the second direction sensor, thereby determining the touch position. When there is only one touch position on the touch panel 10, the controller 12 can locate the two-dimensional coordinates of the touch position, thereby obtaining the position information of the user's finger, but the ghost position may occur during multi-finger detection ( Ghost position). For example, as shown in FIG. 1 , the capacitive sensing amounts of the first direction and the second direction caused by the fingers 16 and 18 touching the touch panel 10 are as shown in the capacitive sensing amount coordinate diagrams on the left and right sides of FIG. 1 , and the controller 12 can thereby It is known that there are two touch positions, but it is impossible to judge the relative relationship between the two touch positions. For example, as shown in FIG. 2, the positions of the fingers 16 and 18 on the touch panel 10 are (X1, Y1) and (X2, Y2), Or (X1, Y2) and (X2, Y1), the capacitance sensing amount distribution on the inductor is the same as the capacitive sensing amount coordinate map shown in Fig. 1, so the controller 12 is extremely easy to misjudge. If you touch (X1, Y1), (X2, Y1), (X1, Y2), and (X2, Y2) four positions at the same time, or any three of these four positions, the capacitance inductance distribution caused by it is also It is the same as the capacitive sensing amount coordinate map shown in Fig. 1, so the controller 12 cannot distinguish whether the touch position is two, three or four. As can be seen from the touch panel 10 shown in FIG. 1, each of the first direction sensors exposes a plurality of sensing electrodes in a first direction, but all are connected in series to the same scanning line 14, as is the second direction sensor. Therefore, the capacitive sensing received by the controller 12 is the same when the sensing electrodes of the same sensor are in different positions. If the capacitive sensing amount distribution scanned by the controller 12 shows that there are two or more touching positions in the first direction and the second direction, the controller 12 cannot accurately determine the actual touching position.

One of the objects of the present invention is to provide a capacitive touch panel that implements a two-dimensional application with a single layer inductor.

One of the objects of the present invention is to provide a capacitive touch panel and a positioning method thereof.

According to the present invention, a capacitive touch panel implementing a two-dimensional application with a single-layer inductor includes a controller connecting a plurality of sensing electrodes distributed on the single-layer inductor by a plurality of scanning lines, but each sensing electrode is individually A scan line is connected to the controller. When the controller is positioned, it is based on the The capacitive sensing amount and position of the sensing electrodes are interpolated to determine the two-dimensional coordinates that are touched.

3 is a schematic diagram of an embodiment of the present invention. The touch panel 24 has a plurality of sensing electrodes 26 in the same layer, the positions of which are represented by B00~B53, and each sensing electrode 26 is connected to the controller by a scanning line 22 alone. 20. When a conductor (for example, a finger) touches the touch panel 24, the controller 20 calculates the two-dimensional coordinates of the touch position according to the position of each of the sensing electrodes 26 and the capacitance sensing amount.

Referring to FIG. 4, the first direction capacitive sensing amount on the touch panel 24 is shown above the touch panel 24. The second direction capacitive sensing amount is shown on the right side of the touch panel 24. Each black dot represents an inductive electrode. The capacitance of 26 is the amount of capacitance. It can be seen from these capacitive sensing coordinate maps that the maximum capacitance sensing amount in the first direction caused by the finger 28 appears at B12, and the maximum capacitance sensing amount in the second direction appears in B03, and B02 and B13 are second. In order to accurately position the two-dimensional coordinates of the finger 28, the present embodiment proposes two operation modes for interpolating 64 points to perform a two-dimensional coordinate positioning operation of the touch position. To simplify the explanation, only the calculation formula of the second direction coordinate is listed below, and the calculation formula of the first direction coordinate can be deduced by analogy.

The first calculation method uses the sensing electrode 26 having the largest capacitance sensing amount as a reference point. For example, in FIG. 4, the maximum capacitance sensing amount in the second direction appears at B03, so the position of B03 is regarded as the coordinate reference point of the interpolation operation, and the second direction coordinate is obtained. X=(B00×64+B01×64×2+B02×64×3+B03×64×4)/(B00+B01+B02+B03), the first direction coordinate is also interpolated with B03 as the reference point Operation.

The second way is to use the sensing electrode 26 whose capacitance is greater than the threshold value as the reference point. For example, the capacitance of B02, B03, B12, and B13 in FIG. 4 is significantly higher than that of other sensing electrodes 26 that are not touched by the finger 28, and therefore are regarded as higher than the threshold value, and serve as a reference point for interpolation operations. Obtain the second direction coordinate X={[(B00×64+B01×64×2+B02×64×3+B03×64×4)/(B00+B01+B02+B03)]+[(B10×64+ B11×64×2+B12×64×3+B13×64×4)/(B10+B11+B12+B13)]}/2. The first direction coordinates are also obtained by the same method.

Compared with the second operation method, the first operation method is relatively simple, but there may be a slight jump point.

FIG. 5 is a schematic diagram of the two-finger detection according to the embodiment of FIG. 3. The capacitive sensing amount caused by the fingers 30 and 32 is shown on the capacitive sensing amount coordinate diagram above and to the right of the touch panel 24, and is also calculated by interpolating 64 points. Touch the two-dimensional coordinates of the position. If the sensing electrode 26 having the largest capacitance sensing amount is used as a reference point for calculation, referring to FIG. 6, the capacitive sensing amount coordinates indicated by broken lines are areas where the capacitances of the fingers 30 and 32 cause changes in the capacitance sensing amount, respectively. The maximum capacitance induction amount in the second direction caused by the finger 30 appears at B02, and the maximum capacitance induction amount in the second direction caused by the finger 32 appears at B33. Therefore, the second direction coordinate of the finger 30 is obtained by calculating B00, B01, B02, B03. X1=(B00×64+B01×64×2+ B02×64×3+B03×64×4)/(B00+B01+B02+B03), the second direction coordinate of the finger 32 is X2=(B30×64+B31×64×2+B32×64×3+B34 ×64 × 4) / (B30 + B31 + B32 + B33). The vertical coordinates of the finger 30 are calculated as B02, B12, B22, B32, B42, B52, and the vertical coordinates of the finger 32 are calculated as B03, B13, B23, B33, B43, B53.

In the second operation mode, the sensing electrode 26 whose capacitance sensing amount is larger than the threshold value is regarded as a reference point. For example, B01, B02, B11, and B12 are regarded as reference points, and the second direction coordinate X1 of the finger 30 can be obtained. ={[(B00×64+B01×64×2+B02×64×3+B03×64×4)/(B00+B01+B02+B03)]+[(B10×64+B11×64×2+ B12×64×2+B13×64×4)/(B10+B11+B12+B13)]}/2, the coordinates of the second direction of the finger 32 are calculated by using B32, B33, B42, and B43 as reference points. X2={[(B30×64+B31×64×2+B32×64×3+B33×64×4)/(B30+B31+B32+B33)]+[(B40×64+B41×64×2 +B42×64×2+B43×64×4)/(B40+B41+B42+B43)]}/2.

In other embodiments, different interpolation points or calculation formulas may be used to provide a two-dimensional coordinate positioning calculation.

The user's finger diameter is 1 cm. In this embodiment, the size of each sensing electrode 26 is designed to be 0.5×0.5 cm ² , so that the finger must be sure to touch at least two sensing electrodes 26 to be interpolated. The operation obtains accurate two-dimensional coordinates. In other embodiments, the size of the sensing electrodes can be implemented in other sizes.

In different embodiments, the sensing electrodes 26 can also be arranged in a non-square manner. For a positive matrix, the two directions of the two-dimensional coordinates may not be orthogonal.

Since the cost of the capacitive touch panel mainly depends on the inductor, the present invention can provide a two-dimensional coordinate positioning capability using only a single layer sensor, thereby effectively reducing the cost.

10‧‧‧ Trackpad

12‧‧‧ Controller

14‧‧‧ scan line

16‧‧‧ fingers

18‧‧‧ fingers

20‧‧‧ Controller

22‧‧‧ scan line

24‧‧‧ Trackpad

26‧‧‧Induction electrodes

28‧‧‧ fingers

30‧‧‧ fingers

32‧‧‧ fingers

1 is a schematic diagram of a conventional capacitive touch panel; FIG. 2 is a schematic diagram of a ghost position; FIG. 3 is a schematic diagram of an embodiment of the present invention; FIG. 4 is a schematic diagram of single finger detection using the embodiment of FIG. 3; FIG. 5 is a schematic diagram of dual finger detection using the embodiment of FIG. 3; and FIG. 6 is another schematic diagram of dual finger detection using the embodiment of FIG. 3.

20‧‧‧ Controller

22‧‧‧ scan line

24‧‧‧ Trackpad

26‧‧‧ sensor

Claims (10)

A capacitive touch panel for realizing a two-dimensional application by using a single-layer inductor includes: a single-layer inductor having a plurality of sensing electrodes; a controller; and a plurality of scanning lines, each of the sensing electrodes independently passing through the plurality of sensing electrodes One of the scan lines is connected to the controller to transmit its capacitive sensing amount to the controller; wherein the controller locates one or more touch positions based on the capacitive sensing amount and position of the sensing electrodes An interpolation operation is performed to determine the two-dimensional coordinates of the one or more touch locations. The capacitive touch panel of claim 1, wherein the controller selects one or more reference points from the sensing electrodes as reference points for the interpolation operation. The capacitive touch panel of claim 1, wherein the controller selects the sensing electrode having the largest capacitive sensing amount in the first direction as the reference point of the first direction, and the sensing electrode of the maximum capacitive sensing amount in the second direction Used as a reference point for this second direction. The capacitive touch panel of claim 1, wherein the controller selects the sensing electrode whose capacitance sensing amount is greater than the first threshold value in the first direction as the reference point of the first direction, and the capacitance sensing amount in the second direction The sensing electrode larger than the second threshold value serves as a reference point for the second direction. A method for positioning a capacitive touch panel, comprising: obtaining a capacitance sensing quantity distribution in a first direction and a second direction from a plurality of sensing electrodes distributed on a single layer inductor; and sensing capacitance according to the sensing electrodes Position and carry out Count to determine the two-dimensional coordinates of one or more touch locations. The positioning method of claim 5, further comprising selecting one or more reference points from the sensing electrodes as the reference point of the interpolation operation. The positioning method of claim 6, wherein the reference point in the first direction is the sensing electrode of the maximum capacitive sensing amount in the first direction, and the reference point in the second direction is the sensing of the maximum capacitive sensing amount in the second direction. electrode. The method of claim 6, wherein the reference point in the first direction is an induction electrode in which the capacitance in the first direction is greater than the first threshold, and the reference point in the second direction is a capacitance in the second direction. The sensing electrode is larger than the second threshold value. The positioning method of claim 7, wherein the step of performing an interpolation operation according to the capacitance sensing amount and the position of the sensing electrodes comprises: capacitance of each sensing electrode in the first direction of the reference point of the first direction The sensing quantity is multiplied by a reference value corresponding to the respective position and a preset number of interpolation points to obtain a plurality of first calculated values; adding the plurality of first calculated values to generate a second calculated value; the reference of the first direction Adding a capacitance sensing amount of all the sensing electrodes in the first direction of the point to generate a third calculated value; dividing the second calculated value by the third calculated value to obtain a first direction coordinate of the touch position; Multiplying the capacitance sensing amount of each sensing electrode in the second direction of the reference point of the two directions by the reference value corresponding to the respective position and the number of the interpolation points to obtain a plurality of fourth calculated values; Adding values produces a fifth calculated value; Adding a capacitive sensing amount of all the sensing electrodes in the second direction of the reference point in the second direction to generate a sixth calculated value; and dividing the fifth calculated value by the sixth calculated value to obtain the touched position The second direction coordinates. The method of claim 8, wherein the step of performing an interpolation operation according to the capacitive sensing amount and the position of the sensing electrodes comprises: obtaining all the first calculated values of the reference points in the first direction, wherein the first The calculating the value includes: multiplying the capacitive sensing amount of each sensing electrode in the first direction of the selected reference point of the first direction by a reference value corresponding to the respective position and a preset interpolation point to obtain a plurality of second calculated values; adding the plurality of second calculated values to generate a third calculated value; adding the capacitive sensing amounts of all the sensing electrodes in the first direction of the selected reference point of the first direction Generating a fourth calculated value; and dividing the third calculated value by the fourth calculated value to obtain the first calculated value; averaging all the first calculated values to obtain a first direction coordinate of the touch position; obtaining all a fifth calculated value of the reference point in the second direction, wherein the step of obtaining the fifth calculated value comprises: sensing capacitive sensing of each of the sensing electrodes in the second direction of the selected reference point of the second direction Multiply the corresponding bit Setting the reference value and the number of interpolation points to obtain a plurality of sixth calculated values; adding the plurality of sixth calculated values to generate a seventh calculated value; and selecting the second selected reference point of the second direction Adding the capacitance sensing amounts of all the sensing electrodes in the direction to generate an eighth calculated value; and dividing the seventh calculated value by the eighth calculated value to obtain the fifth calculated value; and averaging all the fifth calculated values to obtain The second direction coordinate of the touch position.