JP7657522B2 - Touch panel device and display device using the same - Google Patents

Description

The present invention relates to a touch panel device that detects touch operations, and in particular to detecting long presses.

Touch panels are used as an input interface that receives touch operations from the user and are mounted in a display unit together with an LCD display. Resistive and capacitive touch panels are widely used. Capacitive touch panels also come in surface capacitive and projected capacitive types.

Figure 1 shows a schematic plan view of a projected capacitive touch panel (Patent Document 1). The touch panel 6 includes a touch sensor 11. The touch sensor 11 includes an X-side line sensor 12 aligned along the X direction and a Y-side line sensor 13 aligned along the Y direction. The X-side line sensor 12 has electrodes 14 aligned along the X direction arranged in parallel and spaced apart in the Y direction, and the Y-side line sensor 13 has electrodes 15 aligned along the Y direction arranged in parallel and spaced apart in the X direction. In the mutual capacitance method, for example, the X-side line sensors 12 are scanned sequentially, and the Y-side line sensor 13 senses the capacitance at the intersections between the electrodes 14 and 15.

The touch panel device of Patent Document 2 determines whether a contacting object is a foreign object based on a comparison between the actual measured value of the relative acceleration of the contacting object and the theoretical value of the relative acceleration of the foreign object, and the touch panel device of Patent Document 3 determines that the capacitance change is due to a foreign object and not due to a user operation when it detects a change in capacitance but does not detect the proximity of an object using a proximity sensor.

JP 2018-77755 A JP 2014-857717 A JP 2012-138026 A

As shown in FIG. 2(A), in a capacitive touch panel device, the controller 20 scans/senses the touch panel 10 and detects an operation such as a touch at a position where a change in capacitance occurs. However, this detection method has the problem that it is difficult to distinguish whether the change in capacitance has been caused by a long press by a person's finger U, as in FIG. 2(A), or by the placement of an object 30, as in FIG. 2(B). The same problem exists with resistive touch panels.

As shown in FIG. 3, the conventional detection algorithm scans the touch panel 30 and measures the sensing signal obtained by the scan (S100). If the sensing signal is equal to or greater than the touch detection threshold Th (S110), it is then determined whether the sensing signal is a continuing signal (S120). If the continuing signal is within the timeout period (S130), the sensing signal is deemed valid and the coordinates of the touch position detected by the sensing signal are notified to the user. On the other hand, if the continuing signal exceeds the timeout period, the sensing signal is deemed invalid, the data (sensing signal) is discarded, and the touch position is not notified to the user.

However, when this type of timeout processing is performed, for example, when a long press is performed for a long period of time to perform a fast-forward operation or scroll operation, the touch operation is no longer detected due to the timeout processing in the middle of the operation, and as a result, the fast-forward or scroll movement stops and the user is required to perform the fast-forward or other operation again, reducing user convenience.

The present invention aims to solve the above-mentioned problems of the conventional technology and provide a touch panel device and a display device that can identify touches such as long presses.

The touch panel device according to the present invention includes a touch panel and a control means for scanning the touch panel and detecting a touch based on a sensing signal obtained by scanning, and the control means calculates the amount of change between the sensing signal of a previous frame and the sensing signal of a current frame between multiple frames, calculates an integrated value of the multiple calculated amounts of change, and identifies whether or not a touch has occurred based on the calculated integrated value.

In one aspect, the control means calculates a plurality of integrated values between a plurality of frames, and identifies whether or not there is a touch based on an average value of the plurality of integrated values. In one aspect, the control means further calculates a movement of the detection position based on the sensing signals of the plurality of frames, and identifies whether or not there is a touch based on the calculated movement of the detection position and the integrated value. In one aspect, the control means identifies whether or not there is a long press touch. In one aspect, the control means ends the calculation of the integrated value when touch detection is released from the touch panel. In one aspect, the touch panel is a capacitive type or a resistive film type.

According to the present invention, a touch is identified based on the integrated value of the change in the sensing signal between multiple frames, so touches such as long presses can be accurately detected without using timeout processing as in the past. This allows the user to perform continuous operations (long press operations) such as fast forwarding and scrolling, improving user convenience.

FIG. 1 is a schematic plan view of a capacitive touch panel. 1A and 1B are diagrams illustrating problems with a conventional touch panel device. FIG. 11 is a diagram showing an operation flow of a detection algorithm of a conventional touch panel device. 1 is a diagram showing a configuration of a touch panel device according to an embodiment of the present invention; FIG. 5A shows an example of a waveform of a sensing signal when a long press is performed, and FIG. 5B shows an example of a waveform of a sensing signal when an object is placed on the touch panel. FIG. 6(A) is a graph comparing the detection signal when a long press is performed with the detection signal when an object is placed, and FIG. 6(B) is a graph comparing the integrated value when a long press is performed with the integrated value when an object is placed. FIG. 4 is a diagram showing an example of an operation flow of a detection algorithm of the touch panel device according to an embodiment of the present invention.

Next, an embodiment of the present invention will be described. The touch panel device according to the present invention includes a touch panel and detects a touch of an operation target (e.g., a user's finger). The touch includes contact with or proximity to the touch panel. The touch panel device according to the present invention may be either a capacitive touch panel or a resistive touch panel. The touch panel device according to the present invention is mounted on a display such as a liquid crystal panel, and provides a display device or display unit equipped with a user interface function. Such a display device is used, for example, in an in-vehicle device, a multi-function mobile phone (smartphone), a portable information terminal (tablet computer, laptop computer, notebook computer), etc.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram showing the configuration of a touch panel device according to this embodiment. The touch panel device 100 includes, for example, a capacitive touch panel 110 and a controller 120 that performs touch detection on the touch panel 110.

As shown in FIG. 1, the touch panel 110 has a substrate such as glass or plastic on which transparent electrodes 14, 16 are arranged in a matrix in the X and Y directions beneath an insulating film or the like. When a finger touches the touch panel 110, the capacitance between the electrodes in the vicinity changes, and the touch position is detected by identifying this change in capacitance as a row in the X direction and a row in the Y direction. The touch panel 110 is mounted, for example, on a liquid crystal panel (not shown), and provides a user input interface for images displayed on the liquid crystal panel.

The controller 120 controls the overall operation of the touch panel 110. The controller 120 includes a drive circuit for sequentially scanning each electrode 14 of the X-side line sensor 12 shown in FIG. 1, and a sense circuit for sequentially sensing each electrode 15 of the Y-side line sensor 13, and the sense circuit measures a sense signal corresponding to the capacitance generated at the position where the electrodes 14 and 15 intersect (hereinafter, the sensing area). The controller 120 or the sense circuit may include an amplifier circuit that amplifies an analog sense signal corresponding to the capacitance of the sensing area, and an A/D converter that converts the amplified analog sense signal into a digital sense signal. The scanning side may be the Y-side line sensor 13, and the sense side may be the X-side line sensor 12.

The controller 120 scans/senses the entire sensing area of the touch panel 110 via the drive circuit/sense circuit, for example, every 2 to 3 milliseconds. Here, a group of sensing signals that are the measurement results of the entire sensing area of the touch panel 110 is called a frame. Therefore, one frame is generated every 2 to 3 milliseconds. Normally, the time that a finger touches the touch panel 110 is at least several tens of milliseconds. If it takes 3 milliseconds to generate one frame and the finger touch time is 30 milliseconds, then 10 frames will be generated during the period that the finger is touching. Also, if there is a long press, the touch period may be several seconds to several tens of seconds.

The controller 120 detects a touch based on the sensing signal of each frame. In one embodiment, the controller 120 includes a microprocessor or microcontroller with ROM/RAM, etc., and executes a program stored in the ROM/RAM to execute a touch detection algorithm.

Next, a method for identifying a long press in the touch panel device of this embodiment will be described. In a capacitive touch panel or a resistive touch panel, human operation (e.g., a finger) causes slight fluctuations in the capacitance or resistance value. In contrast, when an object is placed on the touch panel, the slight fluctuations in the capacitance or resistance value are very small. In this embodiment, it is possible to identify whether the operation is human (particularly a long press) or something else, based on the difference in behavior of the sensing signal when the operation is performed by a person and when an object is left there.

Figure 5 (A) shows the waveform of a sensing signal when a capacitive touch panel 110 is touched by a person's finger U, and Figure 5 (B) shows the waveform of a sensing signal when an object B is placed on the capacitive touch panel 110, the waveform lasting for about 10 seconds. When finger U touches at time t1, the level of the sensing signal exceeds the touch detection threshold Th in response, and thereafter, the level of the sensing signal remains roughly constant but slight movement occurs. On the other hand, when object B is touched at time t1, the level of the sensing signal exceeds the touch detection threshold Th in response, but there is almost no slight movement at this level. Figure 6 (A) is a graph that shows a schematic representation of the actual waveform of a sensing signal when a finger is pressed and held (solid line) and when an object is left (dashed line).

The controller 120 calculates the amount of change between the level of the sensing signal in the previous frame and the level of the sensing signal in the current frame for a sensing signal that has exceeded the touch detection threshold Th, calculates such amounts of change between multiple frames, and integrates these amounts of change. That is, when the levels of the sensing signals in frames F1, F2, ..., Fn are T1, T2, ..., Tn, the controller 120 calculates T1-T2=△T1, T2-T3=△T2, T3-T4=△T3, ..., Tn-1-Tn=△Tn-1. Then, it calculates the integrated value △c=△T1+△T2+△T3, ... +△Tn-1.

Figure 6 (B) is a graph showing a comparison between the integrated value Δc_U when a finger is pressed and held down and the integrated value Δc_B when an object is left standing. It can be seen that the integrated value Δc_U when a finger is pressed and held down becomes larger than the integrated value Δc_B when the object is left standing as time passes (i.e., the integrated number of changes between frames), and the difference between the two gradually increases.

Therefore, the controller 120 sets an appropriate long press detection threshold Th_U from the relationship shown in FIG. 6(B), and determines whether the integrated value Δc is equal to or greater than the long press detection threshold Th_U. If the integrated value Δc is equal to or greater than the long press detection threshold Th_U, the detection signal is identified as being caused by a long press by a finger, and if the integrated value Δc is less than the long press detection threshold Th_U, the detection signal is identified as being caused by something other than a long press by a finger (e.g., an object being left unattended). In one aspect, the controller 120 may determine whether the integrated value Δc is equal to or greater than the long press detection threshold Th_U at a time corresponding to the time when the conventional detection algorithm times out (step 130 in FIG. 3). In other words, the controller 120 calculates the integrated value Δc of the amount of change between frames in the multiple frames buffered until the timeout occurs, and compares this integrated value Δc with the long press detection threshold Th_U. In one aspect, the determination as to whether the integrated value Δc ≧ the long press detection threshold Th_U may be performed for a predetermined time or number of frames, regardless of the timeout time. In one aspect, the determination as to whether the integrated value Δc ≧ the long press detection threshold Th_U may be performed continuously until the sensing signal becomes less than the touch detection threshold th, that is, until the touch is released. Furthermore, the accumulation of the amount of change between frames may be terminated when the touch is released, or may be terminated when a long press is identified by the determination as to whether the integrated value Δc ≧ the long press detection threshold Th_U.

As described above, according to this embodiment, it is possible to identify whether a long press has been performed by a human finger or an object has been placed on the touch panel without using a timeout process as in the past, which allows the user to perform continuous operations (long press operations) such as fast forwarding and scrolling, thereby improving user convenience. In addition, by accurately identifying a long press by a finger, it is possible to prevent malfunctions (such as unintended calibration operations).

Figure 7 is a flow diagram showing an example of a detection algorithm of this embodiment. The controller 120 scans the touch panel 30, measures the sensing signal obtained by scanning (S100), and determines whether the sensing signal is equal to or greater than the touch detection threshold Th (S110). For example, as shown in Figure 5 (A), when a finger U touches the touch panel 110, the capacitance of the touched sensing area changes, and a sensing signal exceeding the touch detection threshold Th is measured. The controller 120 identifies the touched sensing area from the columns in the X direction and the columns in the Y direction.

When the sensing signal is equal to or greater than the touch detection threshold Th, the controller 120 determines whether the sensing signal is a continuing signal (S120), and if it is a continuing signal, it performs the integration of the amount of change in the sensing signal between frames described above over multiple frames and determines whether the integrated value Δc is greater than or equal to the long press detection threshold Th_U (S200). In one aspect, when the controller 120 determines that the sensing signal is equal to or greater than the touch detection threshold th, it buffers the frame following that frame in a FIFO memory or the like, and determines whether the sensing signal is a continuing signal based on the buffered frame and calculates the integrated value Δc.

The controller 120 calculates an integrated value Δc for a predetermined number of frames or a predetermined time period from touch detection, and if the calculated integrated value Δc is equal to or greater than the long press detection threshold Th_U (S200), the change in capacitance is identified as a long press by a finger (S210) and the coordinate position of the detected touch is notified to the user (e.g., the controller of the display device). On the other hand, if the calculated integrated value Δc is less than the long press detection threshold Th_U (S200), the change in capacitance is identified as an object being left unattended, etc. (S220), the data (sensing signal) is discarded, and the coordinate position is not notified to the user.

Next, a modified example of this embodiment will be described. In the above embodiment, the integrated value Δc is compared with the long press detection threshold Th_U, but the controller 120 may calculate multiple integrated values between multiple frames and compare the average value of the multiple integrated values with the long press detection threshold Th_U. For example, the integrated value Δc_1 of each change amount from frame 1 to frame 3, the integrated value Δc_2 of each change amount from frame 4 to frame 6, and the integrated value Δc_3 of each change amount from frame 7 to frame 9 are calculated, the average value Δc_AV = (Δc_1 + Δc_2 + Δc_3) / 3 is calculated, and it is determined whether Δc_AV is greater than or equal to the long press detection threshold Th_U. With this processing, it is sufficient for the buffer memory to store data for three frames, and the required memory capacity can be reduced.

As another variation, the controller 120 may use the movement of the detection position during the calculation of the integrated value. When an object is left on the touch panel, no change occurs in the detection position, but when a finger touches the touch panel, movement may occur at the detection position. A swipe operation such as scrolling causes movement at the detection position. Therefore, the controller 120 detects the touch position (the sensing area that generates a detection signal equal to or greater than the touch detection threshold Th) based on the detection signal of each frame, and calculates the movement or amount of change ΔM of the detected touch position. The period (number of frames) for calculating the amount of change in the touch position may be the same as the period (number of frames) for calculating the integrated value, or may be shorter than that.

The controller 120 makes it easy to identify a long press by weighting the integrated value Δc by the movement ΔM, for example, (integrated value Δc + movement ΔM) ≧ long press detection threshold Th_U, or (integrated value Δc × movement ΔM) ≧ long press detection threshold Th_U.

The above describes in detail the preferred embodiment of the present invention, but the present invention is not limited to a specific embodiment, and various modifications and variations are possible within the scope of the gist of the invention described in the claims.

12: X-side line sensor 13: Y-side line sensor 14, 15: Electrodes 100: Touch panel device 110: Touch panel 120: Controller U: Finger B: Object

Claims (7)

A touch panel device including a touch panel and a control means for scanning the touch panel and detecting a touch based on a sensing signal obtained by scanning the touch panel,
The control means calculates the amount of change between the level of the sensing signal in the previous frame and the level of the sensing signal in the current frame between multiple frames, calculates an integrated value of the amount of change in the multiple levels obtained by the calculation, and identifies whether or not there is a touch based on the calculated integrated value, without identifying a touch by timeout processing of the sensing signal. The touch panel device according to claim 1, wherein the control means calculates multiple integrated values between multiple frames and identifies whether or not a touch has occurred based on an average value of the multiple integrated values. The touch panel device according to claim 1 or 2, wherein the control means further calculates the movement of the detection position based on the sensing signals of the plurality of frames, and identifies whether or not there is a touch based on the calculated movement of the detection position and the integrated value. The touch panel device according to any one of claims 1 to 3, wherein the control means identifies whether or not a touch is a long press. The touch panel device according to claim 1, wherein the control means terminates the calculation of the integrated value when touch detection is released from the touch panel. The touch panel device according to claim 1, wherein the touch panel is a capacitive type or a resistive type. A display device comprising the touch panel device according to claim 1 and a display.

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