Touch state detection circuit and touch state detection method

Abstract

This invention provides a touch state detection circuit and a touch state detection method that perform detection suitable for various conditions, compared to cases where the scan conditions for the scan process to detect the touch state are fixed. [Solution] The touch IC 20 includes a setting unit 30 that sets scan conditions relating to the execution frequency or execution cycle of the scan process, and a detection unit 32 that performs the scan process according to the set scan conditions and detects the touch state. When the electronic pen is not in use, the setting unit 30 changes and resets the scan conditions so that the execution frequency is lower than the standard or the execution cycle is longer than the standard. The detection unit 32 detects the touch state according to the reset scan conditions.

Description

Technical Field

[0001] The present invention relates to a touch state detection circuit, an electronic device including the touch state detection circuit, and a touch state detection method.

Background Art

[0002] Conventionally, a touch state detection circuit for detecting a touch state where a user's finger or the like touches a detection surface has been known. For example, in the touch state detection circuit described in Patent Document 1 below, a capacitance-type touch sensor in which a plurality of sensor electrodes are arranged in a planar shape is connected, and a scan process for reading and processing detection signals sequentially output from each sensor electrode is executed to detect the touch state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, as an execution cycle of the scan process for detecting the touch state, a fixed time is set so that the touch state detection function can be exhibited in various use cases. As a specific example, it is assumed that 10 fingers of a user touch the detection surface simultaneously, and a long execution cycle is set to the extent that it is not affected by electrical noise caused by this touch. However, in this setting, even when the number of fingers of the user touching the detection surface is small, it takes a fixed time to detect the touch state, resulting in an unnecessary waiting time.

[0005] Therefore, the present invention aims to provide a touch state detection circuit, an electronic device equipped with a touch state detection circuit, and a touch state detection method that can perform detection suitable for various conditions compared to the case where the scan conditions for the scan process for detecting the touch state are fixed. [Means for solving the problem]

[0006] A touch state detection circuit according to a first aspect of the present invention is connected to a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar manner, and detects the user's touch state by performing a scan process that reads and processes detection signals sequentially output from each of the sensor electrodes, comprising: a setting unit that sets scan conditions relating to the frequency or period of execution of the scan process; and a detection unit that performs the scan process with the set scan conditions and detects the touch state, wherein the setting unit changes and resets the scan conditions when a determination condition indicating a situation in which the scan conditions should be changed is met, and the detection unit detects the touch state with the reset scan conditions.

[0007] In the touch state detection circuit according to the second aspect of the present invention, the setting unit, when the first condition is met as the determination condition, modifies and resets the scan conditions so that the execution frequency becomes higher than the standard, or the execution cycle becomes shorter than the standard.

[0008] In the touch state detection circuit according to the third aspect of the present invention, the first condition indicates that when the touch state is detected by at least one finger of the user, the number of fingers is below a threshold.

[0009] In the touch state detection circuit according to the fourth aspect of the present invention, the threshold value is the number of fingers on the user's hand.

[0010] In the touch state detection circuit according to the fifth aspect of the present invention, the first condition indicates that at least the touch state caused by the user's palm has been detected.

[0011] In the touch state detection circuit according to the sixth aspect of the present invention, the first condition indicates that, at a minimum, when the touch state by the user's finger is detected, the movement speed of the finger is below a threshold.

[0012] In the seventh aspect of the present invention, the first condition indicates that the size of the touch sensor is less than or equal to a threshold.

[0013] In the touch state detection circuit according to the eighth aspect of the present invention, the first condition indicates that the refresh rate of the display panel is higher than a threshold when the touch sensor is placed in overlap with the display panel.

[0014] In the touch state detection circuit according to the ninth aspect of the present invention, the first condition indicates that, at a minimum, there is a portion of the entire area in which the touch state can be detected by the touch sensor that does not have the user's intention to touch.

[0015] In the touch state detection circuit according to the tenth aspect of the present invention, the setting unit, when the second condition is met as the determination condition, modifies and resets the scan conditions so that the execution frequency becomes lower than the standard, or the execution cycle becomes longer than the standard.

[0016] In the touch state detection circuit according to the eleventh aspect of the present invention, the second condition indicates that the number of fingers is equal to or greater than a threshold when the touch state is detected by one or more fingers of the user.

[0017] A touch state detection circuit according to the twelfth aspect of the present invention is a touch state detection circuit that further detects the pen state of an electronic pen by performing the scanning process, wherein the second condition indicates that at least the electronic pen is in a non-use state.

[0018] A touch state detection circuit according to a thirteenth aspect of the present invention is a touch state detection circuit that detects the pen state of an electronic pen and the touch state in a time-division manner by executing the scan process, wherein the scan condition indicates the ratio of the execution frequency of the scan process for detecting the touch state to the execution frequency of the scan process for detecting the pen state, and the setting unit changes and resets the execution frequency ratio when the determination condition is met.

[0019] An electronic device according to the fourteenth aspect of the present invention comprises a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar manner, and a touch state detection circuit according to any one of the first to thirteenth aspects connected to the touch sensor.

[0020] A touch state detection method according to a fifteenth aspect of the present invention is a method executed by a detection circuit that is connected to a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar manner and detects the user's touch state by performing a scan process that reads and processes detection signals sequentially output from each of the sensor electrodes, the method being executed by sequentially repeating a setting step of setting scan conditions relating to the frequency of execution of the scan process or the execution period of the scan process, and a detection step of executing the scan process with the set scan conditions and detecting the touch state, wherein in the setting step, if a determination condition indicating a situation in which the scan conditions should be changed is met, the scan conditions are changed and reset, and in the detection step, the touch state is detected with the reset scan conditions. [Effects of the Invention]

[0021] According to the present invention, detection can be performed under various conditions, compared to when the scan conditions for the scan process to detect the touch state are fixed. [Brief explanation of the drawing]

[0022] [Figure 1]It is an overall configuration diagram of an input system incorporated with a touch state detection circuit according to the first embodiment of the present invention. [Figure 2] It is a sequence diagram showing the processing flow of pen detection and touch detection in a touch IC. [Figure 3] It is a functional block diagram showing the touch detection function of the touch IC in FIG. 1. [Figure 4] It is a graph conceptually explaining the touch execution cycle. [Figure 5] It is a graph conceptually explaining the scan time. [Figure 6] It is a diagram for explaining the definition of the scan rate as a scan condition. [Figure 7] It is a diagram showing an example of the combination of a determination condition and the scan rate when the determination condition is satisfied. [Figure 8] It is a flowchart showing an example of the processing flow of a touch IC when executing touch detection by a touch detection function. [Figure 9] It is a flowchart showing an example of the processing flow of the scan setting in step SP14 of FIG. 8. [Figure 10] It is a diagram showing an example of the combination of a determination condition according to the second embodiment and the touch execution cycle (scan time) when the determination condition is satisfied. [Figure 11] It is a flowchart showing an example of the processing flow of the scan setting in step SP14 of FIG. 8 according to the second embodiment. [Figure 12] It is a diagram conceptually explaining the ratio of the scan execution frequency.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, with reference to the accompanying drawings, a touch state detection circuit, an electronic device including the touch state detection circuit, and a touch state detection method according to various embodiments of the present invention will be described. For ease of understanding the description, the same reference numerals are given to the same elements or elements having the same function in each drawing as much as possible, and redundant descriptions are omitted.

[0024] [First Embodiment] First, with reference to Figures 1 to 9, a touch state detection circuit, an electronic device equipped with a touch state detection circuit, and a touch state detection method according to the first embodiment of the present invention will be described.

[0025] <Overall Structure> Figure 1 is an overall configuration diagram of an input system 10 incorporating a touch state detection circuit according to the first embodiment of the present invention. As shown in Figure 1, the input system 10 basically consists of an electronic device 12 having a touch panel display and an electronic pen 14, which is a pen-type pointing device. The electronic pen 14 is also called a "stylus".

[0026] The electronic device 12 consists of, for example, a tablet device, a smartphone, or a personal computer. The user can write pictures or letters on the electronic device 12 by holding the electronic pen 14 in one hand and moving it while pressing the pen tip against the detection surface 16 of the electronic device 12. The user can also perform desired operations via the displayed user controls by touching the detection surface 16 with their finger F.

[0027] The electronic device 12 comprises a touch sensor 18, a touch IC (Integrated Circuit) 20 which is a touch state detection circuit, and a host processor 22. The touch sensor 18 is made up of multiple electrodes arranged in conjunction with a display panel (not shown) such as a liquid crystal. The touch sensor 18 is a capacitive touch sensor made up of multiple sensor electrodes arranged in a planar manner. The touch sensor 18 includes multiple sensor electrodes 18x for detecting a position on the X axis and multiple sensor electrodes 18y for detecting a position on the Y axis. The x and y directions shown in this figure correspond to the X and Y axes of the Cartesian coordinate system defined on the detection surface 16 formed by the touch sensor 18.

[0028] The strip-shaped sensor electrodes 18x are provided extending in the y-direction and arranged at equal intervals along the x-direction. The strip-shaped sensor electrodes 18y are provided extending in the x-direction and arranged at equal intervals along the y-direction. The touch sensor 18 may also be a self-capacitance type sensor in which block-shaped electrodes are arranged in a two-dimensional grid, instead of the mutual capacitance type sensor described above.

[0029] The touch IC 20 is an integrated circuit configured to run firmware 24 and is connected to each of the multiple sensor electrodes 18x, 18y that constitute the touch sensor 18. This firmware 24 performs a scan process that reads and processes the detection signals sequentially output from each of the sensor electrodes 18x, 18y. The firmware 24 is configured to implement a touch detection function 26 that performs a process to detect the touch state of a detection target, which is a part of the human body such as the user's finger F (hereinafter referred to as "touch detection"), by performing the scan process, and a pen detection function 28 that performs a process to detect the pen state of the electronic pen 14 (hereinafter referred to as "pen detection") by performing the scan process. The touch state includes the touch state by one or more of the user's fingers F and the touch state by the user's palm (a part of the hand that is wider than the fingers F, including the palm, back of the hand, fist, etc.). The touch state is the position of the finger F or palm that touches the detection surface 16. The pen state is the position, tilt, and pressure of the electronic pen 14 that touches the detection surface 16.

[0030] Figure 2 is a sequence diagram showing the processing flow of pen detection and touch detection in the touch IC 20. As shown in Figure 2, the touch IC 20 is configured to repeatedly perform pen detection by the pen detection function 28 (step SP10) and touch detection by the touch detection function 26 (step SP12) in a time-division manner. Here, the execution frequency of pen detection and the execution frequency of touch detection are set in advance to a predetermined ratio. In the example in Figure 2, the ratio of the execution frequency of pen detection and touch detection in one repeat cycle is shown as 1:1, but this execution frequency ratio may be 1:n, n:1, or n:m (where n and m are integers).

[0031] The pen detection in step SP10 includes, for example, scanning the touch sensor 18 (global scan or sector scan), receiving and analyzing the downlink signal transmitted from the electronic pen 14, estimating the pen state of the electronic pen 14, and generating and transmitting an uplink signal including commands to the electronic pen 14. The touch detection in step SP12 includes, for example, scanning the touch sensor 18, creating a heatmap (two-dimensional distribution of detection levels) on the touch sensor 18, and estimating the touch state of finger F.

[0032] Returning to Figure 1, the host processor 22 is a processor consisting of a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The host processor 22 reads and executes a program from memory (not shown) to perform, for example, the process of generating digital ink using data from the touch IC 20, and the rendering process for displaying the drawing content indicated by the digital ink.

[0033] <Functional Configuration of Touch IC20> Figure 3 is a functional block diagram showing the touch detection function 26 of the touch IC 20 in Figure 1. As shown in Figure 3, the touch detection function 26 includes a setting unit 30, a detection unit 32, an acquisition unit 34, and a determination unit 36.

[0034] The setting unit 30 sets scan conditions related to the execution frequency or execution cycle of the scan process. Here, the execution frequency of the scan process indicates how often the scan process for detecting the touch state is repeated. The execution cycle of the scan process is the execution cycle of the scan process for detecting the touch state (hereinafter referred to as the "touch execution cycle").

[0035] Figure 4 is a graph that conceptually explains the touch execution cycle. The graph in Figure 4 is a single-axis graph of time, and one scan process is shown as a rectangle. As shown in Figure 4, when touch detection is ON, the scan process to detect the touch state is repeatedly executed multiple times in succession. Note that this scan process does not have to be repeatedly executed multiple times in succession; it may be executed intermittently, for example, by alternating with the scan process to detect the pen state. Specifically, the touch execution cycle is the scan time Ta required for one scan process. Note that since the scan time Ta is a short time, the touch execution cycle may also be the cumulative scan time Tb obtained by accumulating the scan time Ta for a predetermined number of scan processes.

[0036] The scan time Ta (the time required for one scan operation) is the time taken from the time the scan conditions are set, for example, after acquiring the frame data (detection data) for one scan operation, until the scan conditions are set again. A predetermined time is set for the scan time Ta.

[0037] Figure 5 is a graph that conceptually illustrates the scan time Ta. The graph in Figure 5 corresponds to an enlarged view of the scan time Ta portion of the graph in Figure 4. As shown in Figure 5, the scan time Ta includes the actual scan time T1 and the non-scan time T2. The actual scan time T1 (t1~t2) represents the time required for the actual scan process, such as reading out the detection signal, calculation, and outputting the detection data. The non-scan time T2 (t2~t3) represents the waiting time after outputting the detection data until the scan conditions are set again.

[0038] In the first embodiment, the scan condition is described as the scan rate, which relates to the frequency of the scan process for detecting the touch state. The scan rate is also called the scan frequency. Figure 6 is a diagram illustrating the definition of the scan rate as a scan condition, and, as in Figure 4, one scan process is shown by a rectangle. As shown in Figure 6, the scan rate is shown, for example, as the number of scan processes executed per arbitrary time. For example, if the scan process is repeated 5 times with a scan time Ta of 1 [sec], the scan rate for executing those 5 scan processes will be 1 [Hz]. In contrast, if the scan process is repeated 5 times with a scan time Ta of 0.5 [sec], the scan rate for executing those 5 scan processes will be 2 [Hz]. That is, the scan rate changes according to the change in scan time Ta. Furthermore, in a time period in which multiple scan rates are mixed, the scan rate may be calculated as the average value of the scan rates in that time period. For example, if the scan process is repeated 5 times with a scan time Ta of 1 sec, and then repeated 5 times with a scan time Ta of 0.5 sec, the average scan rate for the entire process, which involves a total of 10 scans, will be 1.3 Hz.

[0039] The setting unit 30 sets the initial value of the scan rate to, for example, 100 Hz. The setting unit 30 also changes and resets the scan rate when it meets a determination condition that indicates a situation in which the scan condition, the scan rate, should be changed. This determination condition includes a first condition that indicates a situation in which the scan rate should be higher than the reference value, and a second condition that indicates a situation in which the scan rate should be lower than the reference value. The reference here is the reference value of the scan rate, which may be a value that has been set in advance, for example, as an initial value, or it may be the previous setting value immediately before the determination of the determination condition.

[0040] The setting unit 30 adjusts the scan rate to be higher than the reference when the first condition is met. For example, if the reference is the previous setting value and that previous setting value is 100 Hz, the setting unit 30 resets the scan rate to 150 Hz. Conversely, if the setting unit 30 determines that the second condition is met, it adjusts the scan rate to be lower than the reference. For example, if the reference is the previous setting value and that previous setting value is 150 Hz, the setting unit 30 resets the scan rate to 100 Hz.

[0041] The setting unit 30 resets elements that correlate with the scan time Ta which determines the scan rate, or resets the scan time Ta itself to a period corresponding to these elements, so that the scan rate is reset. Elements that correlate with the scan time Ta include, for example, the signal length of code multiplexing for touch detection and the coordinate calculation time of the detected finger F.

[0042] The code multiplexing signal length refers to the length of the signal in a code multiplexing system that supplies signals with different code patterns to each transmitting conductor. When the detection range is large or there are many targets to detect, it is necessary to increase the number of combinations of signals with different code patterns for each transmitting conductor, and therefore the code multiplexing signal length needs to be increased. In such cases, the setting unit 30 increases the actual scan time T1 at scan time Ta by setting the code multiplexing signal length to be longer. Conversely, when the detection range is small or there are few targets to detect, the code multiplexing signal length may be shortened. In such cases, the setting unit 30 shortens the actual scan time T1 at scan time Ta by setting the code multiplexing signal length to be shorter.

[0043] Furthermore, the time required to calculate the coordinates of detected fingers F depends on the number of fingers F. If there are many fingers F, the time required to calculate the coordinates of those fingers F will be longer, and consequently, the actual scan time T1 at scan time Ta will be longer. Conversely, if there are few fingers F, the time required to calculate the coordinates of those fingers F will be shorter, and consequently, the actual scan time T1 at scan time Ta will be shorter.

[0044] Furthermore, the scan time Ta can be changed by changing the specified time set as the scan time Ta. When the detection range is large or there are many objects to be detected, the actual scan time T1 in scan time Ta becomes longer due to the length of the code multiplexed signal and the time required to calculate the coordinates of finger F, as described above. Therefore, the setting unit 30 adjusts the specified time, i.e., the scan time Ta, to be longer to lower the scan rate. Conversely, when the detection range is small or there are few objects to be detected, the actual scan time T1 in scan time Ta becomes shorter due to the length of the code multiplexed signal and the time required to calculate the coordinates of finger F, as described above. Therefore, the setting unit 30 adjusts the specified time, i.e., the scan time Ta, to be shorter to increase the scan rate.

[0045] As described above, the setting unit 30 optimizes the scan time Ta and the scan rate determined by the scan time Ta. This ensures that the actual scan time T1 at scan time Ta is sufficient to perform the touch state detection function, while shortening or eliminating the non-scan time T2 at scan time Ta to avoid unnecessary waiting time.

[0046] The detection unit 32 performs a scan process to detect the touch state at a scan rate set or reset by the setting unit 30. That is, the detection unit 32 performs the scan process using the signal length of the multicode for touch detection as the signal length of the multicode set or reset by the setting unit 30. The detection unit 32 also performs the scan process using a predetermined time as the predetermined time set or reset by the setting unit 30.

[0047] The detection unit 32, as part of the scan process to detect the touch state, first transmits a touch detection signal to each sensor electrode 18y and receives touch detection signals output from each sensor electrode 18x. Note that in subsequent scan processes, the detection unit 32 may perform the scan process only on the vicinity of the previously detected finger F position. Subsequently, the detection unit 32 creates a heat map showing the detection level for each two-dimensional position of the touch sensor 18 based on the reception results of the touch detection signals.

[0048] Next, the detection unit 32 determines, based on the created heatmap, the region where the change in capacitance between the sensor electrode 18x and the sensor electrode 18y is greater than or equal to a threshold, detects its center position as the position of finger F, and calculates its coordinates. The detection unit 32 then outputs the calculated coordinates to the host processor 22 or the acquisition unit 34. Alternatively, the detection unit 32 may create frame data including the created heatmap and output this frame data to the host processor 22 or the acquisition unit 34.

[0049] Furthermore, the detection unit 32 performs processing to derive touch areas, which are areas touched by finger F, and areas touched by the user's palm, rather than finger F, based on the created heatmap. Specifically, the detection unit 32 determines areas where the change in capacitance formed between sensor electrode 18x and sensor electrode 18y is greater than or equal to a threshold. If the area of ​​such an area is less than or equal to the threshold, it is determined to be a touch area; otherwise, it is determined to be a palm area. The detection unit 32 also outputs information indicating the determined touch areas and palm areas to the host processor 22 and acquisition unit 34.

[0050] The detection unit 32 waits without starting the next scan process until a predetermined time set as the scan time Ta has elapsed, and once that predetermined time has elapsed, it repeats the next scan process again.

[0051] The acquisition unit 34 acquires various types of information for use in the determination unit 36's determination. For example, based on frame data including the coordinates of the fingers F output from the detection unit 32 and a heatmap, the acquisition unit 34 calculates and acquires information indicating the number of fingers F touching the detection surface 16 and the movement speed of those fingers F. The movement speed of the fingers F is the speed at which the fingers F move along the detection surface 16. The acquisition unit 34 also acquires information indicating the touch area and the palm area from the output of the detection unit 32.

[0052] Furthermore, the acquisition unit 34 acquires information indicating the state in which the electronic pen 14 is stored, as well as information indicating the tilt and movement speed of the electronic pen 14, in order to determine whether or not an unused state of the electronic pen 14 has been detected.

[0053] Information indicating the state in which the electronic pen 14 is stored can be obtained, for example, by detecting that the electronic pen 14 has been stored in the electronic device 12 using a sensor, and receiving the detected information from the host processor 22. The tilt of the electronic pen 14 refers to the angle between the normal of the detection surface 16 and the axis of the electronic pen 14. This information indicating the tilt of the electronic pen 14 is calculated based on the distance between two pen coordinates obtained from each of the pen signals transmitted from the two transmitting electrodes of the electronic pen 14 that support tilt detection. Furthermore, information indicating the movement speed of the electronic pen 14 is calculated based on the position coordinates of the electronic pen 14 whose pen state has been detected by the pen detection function 28.

[0054] Furthermore, the acquisition unit 34 acquires information indicating the size of the touch sensor 18 or the number of sensor electrodes 18x, 18y from, for example, the host processor 22. Also, when the touch sensor 18 is placed on top of the display panel, the acquisition unit 34 acquires information indicating the refresh rate of the display panel. The refresh rate is the number of times the display panel is rewritten in any given time, and is indicated, for example, as 70 [Hz]. The acquisition unit 34 acquires information indicating the refresh rate by receiving it from, for example, the host processor 22.

[0055] Furthermore, if there is a portion of the entire area where the touch sensor 18 can detect a touch state that is not intended to be touched by the user, the acquisition unit 34 acquires information indicating the existence of such a portion (hereinafter referred to as "non-touch area information"). For example, in the case of a dual-screen model having two screens, touch detection and pen detection are performed on each of the two screens. When the acquisition unit 34 receives information from the host processor 22 or the like indicating that one of the two screens is in unused mode, it acquires this information as non-touch area information. Also, for example, in the case of a foldable screen configured to be bent, if the touch sensor 18 detects that an object such as a keyboard is placed on a portion of the screen, the acquisition unit 34 receives information indicating this state from the touch sensor 18 and acquires it as non-touch area information. In addition, for example, around the location where a portion of one screen in a dual-screen model or a foldable screen is bent, the electronic pen 14 may be detected simultaneously in multiple areas. Therefore, the acquisition unit 34, based on the tilt of the electronic pen 14 detected by the pen detection function 28, determines that there is an area that is closer to a horizontal state, and acquires the determination result as non-touch area information.

[0056] The determination unit 36 ​​determines whether the determination conditions are met based on the information acquired by, for example, the acquisition unit 34. Figure 7 is a diagram showing an example of a combination of a determination condition and the scan rate when the determination condition is met. As shown in Figure 7, the first condition refers to, for example, the conditions with condition IDs "1" to "6", and the second condition refers to, for example, the conditions with condition IDs "7" and "8". In this embodiment, the determination unit 36 ​​determines that the first condition is met if at least one of the conditions with condition IDs "1" to "6" is met, and determines that the second condition is met if at least one of the conditions with condition IDs "7" and "8" is met.

[0057] Here, "satisfying at least one of the multiple conditions" means not only satisfying any one of the conditions, but also including any combination of the multiple conditions. Therefore, the determination unit 36 ​​may determine that the first condition is satisfied not only when any one of the conditions with condition IDs "1" to "6" is satisfied, but when any combination of these conditions is satisfied, and may determine that the second condition is satisfied not only when either one of the conditions with condition IDs "7" or "8" is satisfied, but when any combination of these conditions is satisfied.

[0058] Condition ID "1" is a condition that increases the scan rate as the number of fingers F touching the detection surface 16 decreases. Specifically, condition ID "1" indicates that when a touch state by one or more fingers F of the user is detected, the number of such fingers F is below a threshold. The threshold here is predetermined by the designer or operator to be at least less than the number of fingers F of the user's hands combined (10 fingers), for example, the number of fingers F of the user's hand combined (5 fingers).

[0059] The determination unit 36 ​​determines the condition of condition ID "1" based on the information indicating the number of fingers F acquired by the acquisition unit 34 as a result of the scan process immediately preceding the determination. When the number of fingers F is less than or equal to the threshold, the coordinate calculation time for the fingers F is shorter compared to when the number of fingers F is greater than the threshold. Also, the probability of multiple fingers F overlapping the same electrode is low, and there is a high possibility that electrical noise caused by finger F touch will be reduced. Therefore, in this case, the signal length of code multiplexing can be shortened, and the specified time set as the scan time Ta can be shortened. As a result, the scan rate can be increased compared to the standard.

[0060] Condition ID "2" is a condition to increase the scan rate when the detection surface 16 is touched by the palm rather than a finger F. Specifically, condition ID "2" indicates that a touch state by the user's palm has been detected. The determination unit 36 ​​affirms the determination of condition ID "2" if information indicating the palm area has been acquired by the acquisition unit 34 as a result of the scan process immediately preceding the determination. When the palm area is detected, one hand is placed on the detection surface 16, so the number of fingers F touching the detection surface 16 is likely to be small. Therefore, in this case, for the same reasons as in the case of condition ID "1", the scan rate can be increased compared to the standard.

[0061] Condition ID "3" is a condition that increases the scan rate as the movement speed of finger F decreases. Specifically, condition ID "3" indicates that when a touch state by the user's finger F is detected, the movement speed of finger F is below a threshold. The threshold here is pre-set by the designer or operator, for example, as 5 [mm / sec]. The determination unit 36 ​​determines the condition of condition ID "3" based on the information indicating the movement speed of finger F acquired by the acquisition unit 34 as a result of the scan process immediately preceding the determination. If the movement speed of finger F is below the threshold, it can be assumed that the area actually used by the user is small and the detection range is small. Therefore, in this case, the signal length of the code multiplexing can be shortened, and the specified time set as the scan time Ta can be shortened. As a result, the scan rate can be increased compared to the standard.

[0062] Condition ID "4" is a condition for increasing the scan rate as the detection range of the touch sensor 18 decreases. Specifically, condition ID "4" indicates that the size of the touch sensor 18 is below a threshold. The threshold here is a size predetermined by the designer or operator to correspond to small electronic devices such as smartphones and tablets, for example, 11 inches. The determination unit 36 ​​determines the condition of condition ID "4" based on the information indicating the size of the touch sensor 18 acquired by the acquisition unit 34. If the size of the touch sensor 18 is below the threshold, the detection range of the touch state is small. Therefore, in this case, the signal length of the code multiplexing can be shortened, and the specified time set as the scan time Ta can be shortened. As a result, the scan rate can be increased compared to the standard. Note that condition ID "4" may also indicate, in addition to or instead of the size of the touch sensor 18, that the number of sensor electrodes 18x,18y is below a threshold.

[0063] Condition ID "5" is a condition that increases the scan rate as the refresh rate of the display panel on which the touch sensor 18 is placed increases. Specifically, condition ID "5" indicates that when the touch sensor 18 is placed on top of the display panel, the refresh rate of the display panel is higher than a threshold. The threshold here is set in advance by the designer or operator as a refresh rate corresponding to the screen display of games, etc., and is, for example, 120 to 160 Hz. The determination unit 36 ​​determines the condition of condition ID "5" based on the information indicating the refresh rate of the display panel acquired by the acquisition unit 34. If the refresh rate of the screen on which the touch sensor 18 is placed is higher than the threshold, the scan rate is increased relative to the reference to match this higher refresh rate.

[0064] Condition ID "6" is a condition for increasing the scan rate when there is an area within the detection range that is not intended to be touched by the user. Specifically, condition ID "6" indicates that there is a sub-area within the entire area where the touch state can be detected by the touch sensor 18 that is not intended to be touched by the user. The determination unit 36 ​​determines that there is a sub-area that is not intended to be touched by the user when non-touch area information is acquired by the acquisition unit 34. When there is a sub-area that is not intended to be touched by the user, the detection range of the touch state is smaller than when there is no such sub-area. Therefore, in this case, the signal length of the code multiplexing can be shortened, and the specified time defined as the scan time Ta can be shortened. As a result, the scan rate can be increased compared to the standard.

[0065] Condition ID "7" is a condition to lower the scan rate as the number of fingers F touching the detection surface 16 increases. Specifically, condition ID "7" indicates that when a touch state by one or more fingers F of the user is detected, the number of such fingers F is greater than or equal to a threshold. The threshold here is predetermined by the designer or operator, for example, to be greater than the number of fingers on one hand of the user (6 to 10 fingers). The determination unit 36 ​​makes a determination of condition ID "7" based on the information indicating the number of fingers F acquired by the acquisition unit 34 as a result of the scan processing immediately before the determination. When the number of fingers F is greater than or equal to the threshold, the coordinate calculation time for those fingers F becomes longer compared to when the number of those fingers F is less than the threshold. Also, the probability of multiple fingers F overlapping on the same electrode is high, and there is a high possibility of increased electrical noise caused by finger F touch. Therefore, in this case, it is necessary to increase the signal length of code multiplexing and increase the specified time set as the scan time Ta. As a result, the scan rate needs to be lower than the standard.

[0066] Condition ID "8" is a condition for lowering the scan rate when the pen state is undetectable. Specifically, condition ID "8" indicates that the electronic pen 14 is detected to be in a non-use state. The determination unit 36 ​​determines that the electronic pen 14 is in a non-use state when information indicating the state in which the electronic pen 14 is stored is acquired by the acquisition unit 34. In addition, the determination unit 36 ​​determines that the electronic pen 14 is in a non-use state if the electronic pen 14 is tilted too far horizontally, based on information indicating the tilt of the electronic pen 14 acquired by the acquisition unit 34 as a result of the scan process immediately before the determination. In addition, the determination unit 36 ​​determines that the electronic pen 14 is in a non-use state if the movement speed is below a threshold, based on information indicating the movement speed of the electronic pen 14 acquired by the acquisition unit 34 as a result of the scan process immediately before the determination. When the electronic pen 14 is in a non-use state, there is a higher probability that more fingers F will touch the detection surface 16 compared to when the electronic pen 14 is in use. Therefore, in this case, for the same reasons as in the case of condition ID "7", the scan rate needs to be higher than the baseline.

[0067] Furthermore, the determination unit 36 ​​makes a determination regarding the processing time for touch detection. For example, the determination unit 36 ​​determines whether or not a predetermined time set or reset as the scan time Ta has elapsed, and outputs the determination result to the detection unit 32.

[0068] <Processing flow of Touch IC20> Next, referring to the flowchart in Figure 8, the processing flow of the touch IC 20 when touch detection is performed by the touch detection function 26 will be explained. Figure 8 is a flowchart showing an example of the processing flow of the touch IC 20 when touch detection is performed by the touch detection function 26. Note that the order of the following steps can be changed as appropriate.

[0069] (Step SP14) When touch detection begins, the setting unit 30 performs the initial scan rate as part of the scan settings, including the setting of scan conditions. After transitioning from the processing in step SP24, the setting unit 30 changes the scan rate and performs a readjustment. Then, the process moves on to the processing in step SP16.

[0070] (Step SP16) The detection unit 32 performs the scan process at the scan rate set or reset in step SP14. Specifically, the detection unit 32 transmits a touch detection signal to each sensor electrode 18y, receives the touch detection signals output from each sensor electrode 18x, and creates a heat map based on the received results. Then, the process proceeds to step SP18.

[0071] (Step SP18) The detection unit 32 calculates the coordinates of the detected finger F based on the heatmap created in step SP16. Then, the process moves on to step SP20.

[0072] (Step SP20) The detection unit 32 outputs the coordinates calculated in step SP18 to the host processor 22. Then, the process proceeds to step SP22.

[0073] (Step SP22) The determination unit 36 ​​determines whether the specified time set or reset as the scan time Ta has elapsed. If the determination is negative, the determination is repeated. If the determination is positive, the process proceeds to step SP24.

[0074] (Step SP24) The determination unit 36 ​​determines whether or not to terminate touch detection. If the determination is negative, the process proceeds to step SP14. If the determination is positive, the series of processes shown in Figure 8 are terminated.

[0075] Figure 9 is a flowchart showing an example of the processing flow for the scan settings in step SP14 of Figure 8.

[0076] (Step SP26) The determination unit 36 ​​determines whether at least one of the conditions with condition IDs "1" to "6" of the first condition is met. If the determination is positive, the process proceeds to step SP28. If the determination is negative, the process proceeds to step SP30.

[0077] (Step SP28) The setting unit 30 resets the scan rate to a higher value than the reference value. Specifically, the setting unit 30 shortens the signal length for code multiplexing and shortens the specified time determined in step SP22 so that the scan rate is the reset value. Then, it finishes the scan setting.

[0078] (Step SP30) The determination unit 36 ​​determines whether at least one of the conditions with condition IDs "7" and "8" of the second condition is met. If the determination is positive, the process proceeds to step SP32. If the determination is negative, the scan setting is terminated without resetting the scan settings.

[0079] (Step SP32) The setting unit 30 resets the scan rate to a lower value compared to the reference value and terminates the scan setting. Specifically, the setting unit 30 increases the length of the code multiplexed signal and also increases the specified time determined in step SP22 so that the scan rate is the reset value. Then it terminates the scan setting.

[0080] <Effects and Effects> In the first embodiment described above, the electronic device 12 includes a capacitive touch sensor 18 having a plurality of sensor electrodes 18x, 18y arranged in a planar manner, and a touch IC 20 connected to the touch sensor 18. The touch IC 20 is a touch state detection circuit IC 20 connected to the touch sensor 18 and which detects the user's touch state by performing a scan process that reads and processes detection signals sequentially output from the sensor electrodes 18x, 18y. The touch IC 20 includes a setting unit 30 that sets a scan rate as a scan condition relating to the frequency of execution of the scan process, and a detection unit 32 that performs the scan process at the set scan rate and detects the touch state. The setting unit 30 changes and resets the scan rate when a determination condition indicating a situation in which the scan rate should be changed is met, and the detection unit 32 detects the touch state at the reset scan rate.

[0081] Furthermore, the touch state detection method for detecting the user's touch state in this touch IC20 sequentially repeats a setting step (step SP14) to set the scan rate and a detection step (steps SP16 to SP24) to detect the touch state by performing a scan process at the set scan rate. In the setting step, if the determination conditions are met, the scan rate is changed and reset, and in the detection step, the touch state is detected at the reset scan rate.

[0082] According to the touch IC 20, electronic device 12, and touch state detection method of the first embodiment, the scan rate is changed and reset when the determination conditions are met, so the scan time Ta can be varied and optimized according to the detection target, detection range, etc. This ensures that the actual scan time T1 is sufficient to perform the touch state detection function, and the non-scan time T2 can be shortened or eliminated to avoid unnecessary waiting time. As a result, detection suitable for various conditions can be performed compared to when the scan rate is fixed.

[0083] Furthermore, the setting unit 30, when the first condition is met as a determination criterion, changes the scan rate to a higher value compared to the standard and resets it. The first condition is at least one of the conditions with condition IDs "1" to "6" shown in Figure 7.

[0084] With this configuration, the scan rate can be increased and the scan time Ta shortened depending on whether at least one of the conditions IDs "1" to "6" is met. In particular, under condition ID "1", the threshold can be set to 5 fingers, which is the number of fingers F on the user's hand, allowing for optimization of the scan time Ta in distinction from two-handed touches.

[0085] Furthermore, the setting unit 30, when the second condition is met as a determination criterion, changes the scan rate to a lower value compared to the standard and resets it. The second condition is at least one of the conditions with condition IDs "7" and "8" shown in Figure 7.

[0086] With this configuration, the scan rate can be lowered and the scan time Ta increased depending on whether at least one of the conditions IDs "7" or "8" is met.

[0087] [Second Embodiment] Next, with reference to Figures 10 and 11, a touch state detection circuit, an electronic device equipped with the touch state detection circuit, and a touch state detection method according to the second embodiment of the present invention will be described. Similar to the first embodiment, the touch state detection circuit according to the second embodiment is configured such that the electronic device 12 includes a touch IC 20 which is the touch state detection circuit. Hereinafter, the same reference numerals will be used for components or functions similar to those in the first embodiment, and their descriptions will be omitted as appropriate. Differences from the first embodiment will be described.

[0088] <Functional Configuration of Touch IC20> The second embodiment differs from the first embodiment in that the scan condition is not the scan rate, but rather a scan condition relating to the touch execution cycle, specifically the scan time Ta which is the touch execution cycle.

[0089] The setting unit 30 sets the initial value of the scan time Ta to, for example, 10 [mmsec]. The setting unit 30 changes and resets the scan time Ta when it satisfies a determination condition indicating a situation in which the scan condition, the scan time Ta, should be changed. This determination condition includes a first condition indicating a situation in which the scan time Ta should be shorter than the reference value, and a second condition indicating a situation in which the scan time Ta should be longer than the reference value. The reference here is the reference value of the scan time Ta, which may be a value set in advance as, for example, an initial value, the previous setting value immediately before the determination of the determination condition, or the pen scan time. The pen scan time is the scan time required for one scan process to detect the pen state, and corresponds to the scan time Ta.

[0090] The setting unit 30 adjusts the scan time Ta to be shorter than the reference time when the first condition is met. Conversely, the setting unit 30 adjusts the scan time Ta to be longer than the reference time when it is determined that the second condition is met. Note that if the reference time is the pen scan time, the change in scan time Ta may be a relative change to the pen scan time by changing the pen scan time. For example, the scan time Ta relative to the pen scan time may be increased by stopping the scan process for detecting the pen state and setting the pen scan time to 0.

[0091] The detection unit 32 performs a scan process to detect the touch state for a scan time Ta set or reset by the setting unit 30.

[0092] Figure 10 is a diagram showing an example of a combination of the determination conditions according to the second embodiment and the touch execution cycle (scan time Ta) when the determination conditions are met, and corresponds to Figure 7. As shown in Figure 10, the determination conditions in the second embodiment are the same as the determination conditions according to the first embodiment.

[0093] <Processing flow of Touch IC20> In the second embodiment, the processing flow of the touch IC 20 when the touch detection function 26 performs touch detection is the same as the flowchart shown in Figure 8. Also, in the second embodiment, the processing flow of the scan setting in step SP14 of Figure 8 is shown by the flowchart shown in Figure 11 instead of the flowchart shown in Figure 9. Figure 11 is a flowchart showing an example of the processing flow of the scan setting in step SP14 of Figure 8 according to the second embodiment, and corresponds to the flowchart shown in Figure 9. Note that the order of the following steps can be changed as appropriate.

[0094] (Step SP34) The determination unit 36 ​​determines whether at least one of the conditions with condition IDs "1" to "6" of the first condition is met. If the determination is positive, the process proceeds to step SP36. If the determination is negative, the process proceeds to step SP38.

[0095] (Step SP36) The setting unit 30 readjusts the scan time Ta, which is the touch execution cycle, to a shorter value than the reference value. Then, it finishes the scan setting.

[0096] (Step SP38) The determination unit 36 ​​determines whether at least one of the conditions with condition IDs "7" and "8" of the second condition is met. If the determination is positive, the process proceeds to step SP40. If the determination is negative, the scan setting is terminated without resetting the scan settings.

[0097] (Step SP40) The setting unit 30 readjusts the scan time Ta, which is the touch execution cycle, to a longer value than the reference value, and then terminates the scan settings.

[0098] <Effects and Effects> As described above, in the second embodiment as well, the electronic device 12 includes a capacitive touch sensor 18 having a plurality of sensor electrodes 18x, 18y arranged in a planar manner, and a touch IC 20 connected to the touch sensor 18. The touch IC 20 according to the second embodiment includes a setting unit 30 that sets a scan time Ta, which is the touch execution cycle, as a scan condition, and a detection unit 32 that performs a scan process at the set scan time Ta and detects the touch state. The setting unit 30 changes and resets the scan time Ta when it satisfies a determination condition indicating a situation in which the scan time Ta should be changed, and the detection unit 32 detects the touch state at the reset scan time Ta.

[0099] Furthermore, the touch state detection method for detecting the user's touch state in the touch IC20 according to the second embodiment sequentially executes a setting step (step SP14) to set a scan time Ta which is the touch execution cycle, and a detection step (steps SP16 to SP24) to detect the touch state by performing a scan process with the set scan time Ta. In the setting step, if the determination condition is met, the scan time Ta is changed and reset, and in the detection step, the touch state is detected with the reset scan time Ta.

[0100] Therefore, according to the touch IC 20, electronic device 12, and touch state detection method of the second embodiment, the scan time Ta is changed and reset when the determination conditions are met, so that the scan time Ta can be varied according to the detection target, detection range, etc. As a result, similar to the first embodiment, detection suitable for various conditions can be performed compared to when the scan time Ta is fixed.

[0101] Furthermore, the setting unit 30, when the first condition is met as a determination criterion, changes the scan time Ta to be shorter than the standard and resets it. The first condition is at least one of the conditions with condition IDs "1" to "6" shown in Figure 10.

[0102] This configuration allows for a reduction in scan time Ta depending on whether at least one of the conditions IDs "1" to "6" is met. In particular, under condition ID "1", the threshold is set to 5 fingers, which is the number of fingers F on the user's hand, allowing for optimization of scan time Ta in distinction from two-handed touches.

[0103] Furthermore, the setting unit 30, when the second condition is met as a determination criterion, changes the scan time Ta to be longer than the standard and resets it. The second condition is at least one of the conditions with condition IDs "7" and "8" shown in Figure 10.

[0104] With this configuration, the scan time Ta can be extended depending on whether at least one of the conditions of condition ID "7" or "8" is met.

[0105] <Variation> The present invention is not limited to the embodiments described above. That is, any design modifications made to the above embodiments by those skilled in the art are also included within the scope of the present invention, as long as they retain the features of the present invention. Furthermore, the elements of the above embodiments and the modifications described later can be combined to the extent that it is technically possible, and any combination thereof is also included within the scope of the present invention, as long as it retains the features of the present invention.

[0106] For example, in the first embodiment, an example was described in which both the code multiplexing signal length and the specified time are changed to achieve a reset scan rate, but the method is not limited to this. For example, either the code multiplexing signal length or the specified time may be changed, or other elements may be changed. Also, an example was described in which the scan rate is reset by changing the specified time set as the scan time Ta, but the scan rate may be reset not only by changing the scan time Ta, but also by changing the specified time set as, for example, the integrated scan time Tb.

[0107] Furthermore, in the second embodiment, the scan condition relating to the touch execution cycle was described as the scan time Ta, but the scan condition relating to the touch execution cycle may also be the integrated scan time Tb.

[0108] Furthermore, the scan conditions are not limited to control parameters that focus solely on touch detection, but may also be conditions relating to control parameters that focus on time-division detection of pen state and touch state. For example, the scan conditions may be the ratio of the frequency of execution of the scan process for detecting the touch state to the frequency of execution of the scan process for detecting the pen state (hereinafter referred to as the "scan execution frequency ratio"). That is, the setting unit 30 may change and reset the scan execution frequency ratio when the determination condition is met.

[0109] Figure 12 is a diagram for conceptually explaining the ratio of scan execution frequencies. In Figure 12, one scan operation for touch detection is shown as a black square, and one scan operation for pen detection is shown as a white square, out of 10 scan operations performed over an arbitrary time ΔT. Thus, Figure 12 conceptually shows the ratio of the number of scan operations for pen detection to the number of scan operations for touch detection within a predetermined number of operations. Figure 12(A) shows the case where the ratio of scan execution frequencies (pen detection:touch detection) is 5:5, and Figure 12(B) shows the case where the ratio of scan execution frequencies (pen detection:touch detection) is 6:4. The setting unit 30 changes the ratio of scan execution frequencies from, for example, 5:5 as shown in Figure 12(A) to 6:4 as shown in Figure 12(B). By changing the ratio of scan execution frequencies in this way, it is possible to change the number of scan operations over an arbitrary time ΔT, even if, for example, the scan time Ta required for one scan operation is fixed. In other words, even if the execution frequency of the scan process within touch detection is fixed, the overall execution frequency of the scan process within the entire scan process, which includes both pen detection and touch detection, can be changed. As a result, detection suitable for various conditions can be performed.

[0110] Furthermore, the scan conditions are not limited to just one of the scan rate, touch execution cycle, and scan execution frequency ratio, but may also be a combination of these. In other words, if the determination conditions are met, the setting unit 30 may change and reset the scan conditions to any combination of the scan rate, touch execution cycle, and scan execution frequency ratio, rather than just one of these conditions.

[0111] Furthermore, the present invention may also be a program for causing information processing devices such as the touch IC 20 and the electronic device 12 to function as shown in Figure 3. The program may be stored in a storage means located inside the touch IC 20 or the electronic device 12, or it may be stored in an external storage means connected to the touch IC 20 or the electronic device 12 via a network. The program may also be provided by recording it on a computer-readable recording medium, or it may be provided in a form that can be installed via a network such as the Internet. [Explanation of Symbols]

[0112] 18x, 18y: Sensor electrodes, 18: Touch sensor, 20: Touch IC (touch state detection circuit), 30: Setting unit, 32: Detection unit, F: Finger

Claims

1. A touch state detection circuit is connected to a capacitive touch sensor having multiple sensor electrodes arranged in a planar manner, and detects the user's touch state and the pen state of an electronic pen by scanning using detection signals from the sensor electrodes, A setting unit for setting scan conditions related to the execution frequency or execution cycle of the scan process, A detection unit that performs the scan process according to the set scan conditions and detects the touch state, Equipped with, The setting unit, when the electronic pen is not in use, modifies and resets the scan conditions so that the execution frequency is lower than the standard, or the execution cycle is longer than the standard. The detection unit detects the touch state with the reset scan conditions. Touch state detection circuit.

2. The non-use state of the electronic pen includes the state in which it is detected that the electronic pen has been stored in the electronic device having the touch sensor. The touch state detection circuit according to claim 1.

3. The setting unit, as a change to the scan conditions, sets the length of the code-multiplexed signal used for scanning the sensor electrode to be longer. The touch state detection circuit according to claim 1.

4. The scan conditions include the ratio of the frequency of performing the scan process to detect the touch state to the frequency of performing the scan process to detect the pen state. The setting unit changes the ratio so that the frequency of the touch state is reduced when the electronic pen is not in use. The touch state detection circuit according to claim 1.

5. The setting unit modifies and resets the scan conditions when the electronic pen is not in use and there is a portion of the total area detectable by the touch sensor that is not intended to be touched by the user. The touch state detection circuit according to claim 1.

6. A touch state detection method is performed by a detection circuit that is connected to a capacitive touch sensor having multiple sensor electrodes arranged in a planar manner, and which detects the user's touch state and the pen state of an electronic pen by scanning using detection signals from the sensor electrodes, The following steps are sequentially repeated: a setting step of setting scan conditions relating to the execution frequency or execution cycle of the scan process, and a detection step of executing the scan process with the set scan conditions and detecting the touch state. In the setting step, when the electronic pen is not in use, the scan conditions are changed and reset so that the execution frequency is lower than the standard, or the execution cycle is longer than the standard. In the detection step, the touch state is detected using the reset scan conditions. Method for detecting touch state.

7. The non-use state of the electronic pen includes the state in which it is detected that the electronic pen has been stored in the electronic device having the touch sensor. The method for detecting a touch state according to claim 6.

8. In the setting step, as a change to the scan conditions, the length of the code-multiplexed signal used for scanning the sensor electrode is set to be longer. The method for detecting a touch state according to claim 6.

9. The scan conditions include the ratio of the frequency of performing the scan process to detect the touch state to the frequency of performing the scan process to detect the pen state. In the setting step, if the electronic pen is detected to be in a non-use state, the ratio is changed so that the frequency of the touch state is reduced. The method for detecting a touch state according to claim 6.

10. In the setting step, if the electronic pen is not in use and there is a portion of the total area detectable by the touch sensor that is not intended to be touched by the user, the scan conditions are changed and reset. The method for detecting a touch state according to claim 6.

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