JP5809516B2 - TOUCH TYPE INPUT DEVICE, ITS CONTROLLER, CONTROL METHOD, AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to a touch-type input device that utilizes a change in capacitance.

  Many of electronic devices such as computers, mobile phone terminals, and PDAs (Personal Digital Assistants) in recent years include an input device for operating the electronic device by touching with a finger or a stylus pen.

  One of such input devices is a touch-type input device (also referred to as a touch sensor, a touch pad, or a track pad) that is formed between an electrode and its surroundings when a user's finger or pen comes into contact with the touch input device. An electrostatic sensor using the change in capacitance is used. The touch-type input device includes a plurality of sensor electrodes arranged in the X-axis direction, a plurality of sensor electrodes arranged in the Y-axis direction, and a detection circuit that detects the capacitance of each sensor electrode. The detection circuit determines a position touched by the user by determining a sensor electrode having a large change in capacitance, that is, a sensor electrode touched by the user.

JP 2001-325858 A Special table 2003-511799 gazette US Pat. No. 5,825,352 A1 JP 2007-013342 A Japanese Patent Laid-Open No. 11-2332034

  The detection circuit compares the change in capacitance with a predetermined threshold value, and determines that the user has touched when the threshold value is exceeded. Here, the user touches the panel with bare fingers, touches with a gloved finger, or touches with a pen. The amount of change in capacitance that occurs when the user touches the panel depends on the material, area, and the like of an object that contacts the panel (referred to as a contact object).

  FIG. 1 is a diagram illustrating the relationship between the type of contact object, the amount of change in capacitance, and the range in which capacitance change occurs. When the contact is a bare finger, the amount of change in capacitance is the largest, smaller with a gloved finger, and smaller with a stylus pen. In addition, when the contact object is a bare finger, the range in which the capacitance change occurs is the widest, with a gloved finger being narrower and with a stylus pen being even narrower.

  In such a situation, when a fixed threshold is used when determining the presence or absence of contact, a good sensitivity can be obtained for one contact object, but the sensitivity is deteriorated for another contact object. Problems arise.

  The present invention has been made in view of such a problem, and one of exemplary purposes of an aspect thereof is to provide an input device capable of realizing good sensitivity with respect to various contact objects.

  One embodiment of the present invention relates to a controller for a touch-type input device having a plurality of sensor electrodes whose capacitances change in accordance with a user's contact state. The controller receives capacitance value data indicating the capacitance of each of the plurality of sensor electrodes generated for each frame cycle, and generates a peak detection unit for determining the peak capacitance value data having the largest capacitance, and for each frame cycle. An arithmetic processing unit that compares the peak capacity value data to be compared with a threshold value to determine whether or not the user has touched, and a threshold value control unit that controls the threshold value. When the peak capacity value data smaller than the current threshold value and larger than the predetermined minimum value is continuously detected over a predetermined number of frames, the threshold value control unit sets the threshold value at the predetermined number of frames. The average value of the obtained peak capacity value data is updated to a value obtained by multiplying a predetermined coefficient K (0 <K <1).

  Since the peak capacity value data changes according to the contact object, the contact object can be estimated by monitoring the peak capacity value data. According to this aspect, since the threshold value can be dynamically set according to the contact object, good sensitivity can be realized for various contact objects.

  The predetermined coefficient K may be ½.

The threshold value control unit may return the threshold value to a predetermined initial value when detecting peak capacity value data equal to or less than the minimum value.
A state where the peak capacity value data is equal to or less than the minimum value can be determined as a non-contact state of the panel. In this case, the initial value specified for the standard contact object is restored.

  The initial value may be a midpoint between the maximum value and the minimum value that the capacitance value data can take.

  Another aspect of the present invention relates to a touch input device. The input device includes a panel and the controller according to any one of the above aspects.

  Another embodiment of the present invention relates to an electronic device. The electronic device includes the above-described input device.

  It should be noted that any combination of the above-described constituent elements and the expression of the present invention converted between methods, apparatuses, etc. are also effective as an aspect of the present invention.

  According to an aspect of the present invention, good sensitivity can be realized for various contact objects.

It is a figure explaining the relationship between the kind of contact thing, the variation | change_quantity of an electrostatic capacitance, and the range which a capacitance change generate | occur | produces. It is a block diagram which shows the structure of an electronic device provided with the touch-type input device which concerns on 1st Embodiment. It is a block diagram which shows the structure of the input device which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the threshold value control part of FIG. It is a figure which shows operation | movement of a panel controller. 6A and 6B are flowcharts for determining a contact object. FIGS. 7A and 7B are diagrams showing a display screen of the LCD.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

(First embodiment)
FIG. 2 is a block diagram illustrating a configuration of the electronic apparatus 1 including the touch-type input device 2 according to the first embodiment. The input device (touch type input device) 2 is disposed, for example, at a position overlapping with an LCD (Liquid Crystal Display) 9, that is, on the surface layer of the LCD 9, and functions as a touch panel. Alternatively, it may be an input device such as a trackpad arranged at a different location from the LCD 9.

  The input device 2 includes a sensor unit 4, a capacitance detection circuit 10, and a panel controller 6. When the user touches the surface of the sensor unit 4 with a contact object 8 such as a finger, the capacitance formed between the sensor electrode arranged inside the sensor unit 4 and the surroundings changes. The sensor unit 4 has an array of a plurality of sensor electrodes arranged in a staggered matrix. Note that the capacitance detection circuit 10 and the panel controller 6 may be configured integrally.

  The capacitance detection circuit 10 detects a change in the capacitance of the sensor electrode and outputs data corresponding to the detection result to the panel controller 6. The panel controller 6 is a so-called DSP (Digital Signal Processor), analyzes data from the capacitance detection circuit 10, and determines the presence / absence and type of a user input operation. For example, when the contact object 8 contacts the sensor unit 4, selection of an item or object displayed on the LCD 9 is selected, or character input is assisted.

  When the user touches the sensor unit 4 with a finger, the capacitance of the sensor electrode SE immediately below the finger changes. When a plurality of user's fingers come into contact, the capacitance of the sensor electrode SE immediately below each finger changes. Further, the capacitance of the sensor electrode SE around the sensor electrode SE immediately below the finger also changes slightly. As shown in FIG. 1, the range of the peripheral sensor electrode SE in which the capacitance change occurs depends on the type of the contact object 8.

FIG. 3 is a block diagram illustrating a configuration of the input device 2 according to the first embodiment. The input device 2 includes a plurality of sensor electrodes SE _{i, j} , a capacitance detection circuit 10, and a panel controller 6. As described above, the plurality of sensor electrodes SE _{i, j} are arranged in a matrix. The subscripts _{i and j} indicate an element in the i-th row and the j-th column.

The capacitance detection circuit 10 is connected to a plurality of sensor electrodes SE _{1,1 to} SEM _{, N} , measures the capacitance of each sensor electrode SE _{i, j} , and capacitance value data C indicating the measured capacitance. Generate an array of _{i, j} . The C / V conversion circuit 12 generates voltages V _{1,1 to} V _{M, N} according to the capacitance. The A / D conversion circuit 14 converts the voltages V _{1,1 to} VM _{, N} into digital capacitance value data C _{1,1 to} CM _{, N.}

A set of capacity value data C _{1,1 to} C _{M, N} is generated every predetermined frame period. The panel controller 6 includes a peak detector 16, an arithmetic processor 18, and a threshold controller 20. The peak detector 16 determines the capacitance value data (referred to as peak capacitance value data) C _PEAK having the largest capacitance based on the plurality of capacitance value data C _{1,1 to} C _{M, N} , and the capacitance value is maximum. The sensor electrode (referred to as a peak electrode) SE _PEAK is identified. In the case of performing multi-touch detection, when there are a plurality of peaks, data indicating each peak is generated. The peak detection unit 16 generates peak capacity value data C _PEAK for each frame and outputs it to the threshold control unit 20. The peak detector 16 may output data PEAK for specifying the peak electrode SE _PEAK instead of or in addition to the peak capacitance value data C _PEAK .

The arithmetic processing unit 18 compares the peak capacity value data C _PEAK generated for each frame period with the threshold value TH, and determines the presence or absence of the user's contact. The arithmetic processing unit 18 calculates the coordinates x, y touched by the user based on the capacitance value data C _{1,1 to} C _{M, N.} The specific arithmetic algorithm of the arithmetic processing unit 18 is not particularly limited, and the arithmetic processing unit 18 may adopt a known or future usable algorithm.

The threshold control unit 20 dynamically controls the threshold TH based on the peak capacity value data C _PEAK . A predetermined initial value TH _INIT and a predetermined minimum value TH _LOW are defined for the threshold value TH. For example, the initial value TH _INIT is the optimum threshold value TH for the contact object 8 assumed as a standard input means. For example, the standard contact 8 is a bare finger. The initial value TH _INIT may be a midpoint between the maximum value and the minimum value that the capacitance value data can take. When the capacitance value data is 8 bits, the initial value TH _INIT is set to 127. The minimum value TH _LOW is set to a value substantially close to zero, for example, around 0 to 4.
The minimum value TH _LOW and the initial value TH _INIT may be values that can provide good sensitivity for each system.

The threshold control unit 20 compares the peak capacity value data C _PEAK generated for each frame with the current threshold TH and the minimum value TH _LOW . When peak capacity value data C _PEAK smaller than the threshold value TH and larger than the minimum value TH _LOW is continuously detected over a predetermined number of frames N (N is an integer of 2 or more), the threshold value TH _Is updated to a value obtained by multiplying the average value of the peak capacity value data C _PEAK obtained in a predetermined number of frames N by a predetermined coefficient K (0 <K <1). For example, K = 1/2 is exemplified, but the value may be set to a value that can provide good sensitivity for each system.

Further, the threshold value control unit 20 returns the threshold value TH to a predetermined initial value TH _INIT when detecting the peak capacity value data C _PEAK that is not more than the minimum value TH _LOW . In the present embodiment, a state in which the peak capacity value data C _PEAK is equal to or less than the minimum value TH _LOW is estimated as a state in which a series of input processes by the user is completed and a non-contact state is established. Then, when the input process starts next, it is assumed that the contact object 8 (for example, a finger) which is a standard input means is used, and the threshold value TH is returned to the initial value TH _INIT .

FIG. 4 is a flowchart showing the operation of the threshold control unit 20 of FIG. First, an initial value TH _INIT is given to the threshold value TH (S100). Subsequently, the count number CNT is initialized to zero (S102).

For each frame, peak capacity value data C _PEAK is acquired (S104). When the peak capacity value data C _PEAK is equal to or _smaller than the minimum value TH _LOW (Y in S106), the process returns to step S100, and the threshold value TH is returned to the initial value TH _INIT .

When the peak capacity value data C _PEAK is larger than the minimum value TH _LOW (N in S106) and the peak capacity value data C _PEAK is smaller than the current threshold value TH (Y in S108), the count number CNT is incremented ( S110). When the peak capacity value data C _PEAK is equal to or greater than the current threshold value TH (N in S108), the process returns to step S102, and the count number CNT is reset to zero.

  The above processing is repeated until the count number CNT reaches a predetermined frame number N (N in S112). When the count number CNT reaches a predetermined frame number N (Y in S112), an average value AVE of threshold values TH for the past N frames is calculated (S114), and the threshold value TH corresponds to the average value AVE. The value AVE × K is set (S116). Then, the process returns to step S102.

The above is the configuration of the panel controller 6. Next, the operation will be described. FIG. 5 is a diagram illustrating the operation of the panel controller 6. In FIG. 5, the horizontal axis indicates the elapsed time, that is, the number of frames, the solid line indicates the peak capacity value data C _PEAK , and the broken line indicates the threshold value TH.

Prior to time t1, since the peak capacity value data C _PEAK is equal to or less than the minimum value TH _LOW (Y in S106), the threshold value TH maintains the initial value TH _INIT = 127. When the user touches the panel with a finger at time t1 to t2, the peak capacitance value data C _PEAK increases, but the threshold value TH is not changed because it maintains a value higher than the threshold value TH.

From time t3 to t5, the user touches the panel with the pen. At this time, the peak capacity value data C _PEAK has a value smaller than that at times t1 to t2, and TH _LOW <C _PEAK <TH is satisfied. When this state continues for N frames, the threshold value TH is updated (time t4). Thereafter, the threshold value TH is maintained while touching with the pen. When the pen is removed from the panel at time t5, the peak capacity value data C _PEAK again becomes the minimum value TH _LOW or less, and the threshold value TH is initialized (time t6).

During the period from t7 to t9, when the user touches the panel with a pen, the peak capacity value data C _PEAK takes a low value. When the state of TH _LOW <C _PEAK <TH continues for N frames (time t8), the threshold value TH is updated.

After the section t9, when the user touches the panel again with a finger, the peak capacity value data C _PEAK increases. As the peak capacity value data C _PEAK increases, the average value AVE for the past N frames sequentially increases. As a result, the threshold value TH gradually increases (time t10 to t12).

After time t11, when the user's finger slowly moves away from the panel, the peak capacity value data C _PEAK decreases with time. From time t13 when C _PEAK <TH, to time t14 after the lapse of N frames, the threshold value TH is set to a value that is ½ times the average value AVE of time t13 to t14.

When C _PEAK <TH _LOW is detected at time t15, the threshold value TH is initialized.

Thus, according to the panel controller 6 which _concerns on 1st Embodiment, the contact thing 8 can be estimated according to the peak capacity _| capacitance value data _CPEAK . Specifically, when the peak capacity value data C _PEAK is larger than the threshold value TH, the contact object 8 that causes a large capacity change such as a finger is estimated. On the contrary, when the peak capacitance value data C _PEAK falls below the threshold value TH, the contact object 8 that causes a small capacitance change such as a pen is estimated. According to the panel controller 6, the optimum threshold value TH can be dynamically set according to the estimated contact object 8, and as a result, even in an electronic device in which various contact objects 8 are assumed, it is good. Sensitivity can be realized.

(Second Embodiment)
In the first embodiment, the technique of estimating the contact object 8 based on the peak capacity value data C _PEAK and changing the threshold value TH according to the result has been described. In the second embodiment, a technique for changing the operation of the application software according to the estimated contact object 8 will be described.

As shown in FIG. 1, the amount of change in capacitance, that is, the peak capacitance value data C _PEAK depends on the contact object 8, and the range in which the capacity change occurs also depends on the contact object 8. Therefore, in the second embodiment, the arithmetic processing unit 18 estimates the contact object 8 based on the set of the peak capacity value data C _PEAK and / or the capacity value data C _{1,1 to} C _{M, N} , and the contact Data OBJ indicating the object 8 is output to an external processor.

6A and 6B are flowcharts for determining a contact object.
In FIG. 6A, a first contact object and a second contact object other than that are assumed as the contact object 8. The first contact object may be a user's finger, and the second contact object may be a pen. When the threshold value TH is updated according to step S116 of FIG. 4 (S200), the contact object is determined to be the second contact object. When the threshold value TH is not changed, the contact object is determined as the first contact object.

More simply, the first contact object and the second contact object may be determined according to whether the peak capacity value data C _PEAK is larger or smaller than the threshold level. For example, if the threshold level is the value x1 in FIG. 1, it can be determined whether the contact 8 is a finger or the other. If the value is x2, it is determined whether the contact is a pen or the other. it can.

Alternatively, as another method, the first contact object and the second contact object may be determined according to whether the range in which the capacitance change occurs is larger or smaller than the threshold level. For example, when the threshold level is the value r1 in FIG. 1, it can be determined whether the contact object 8 is a finger or the other, and when the value r2 is set, it is determined whether the contact object is a pen or the other it can. The range in which the capacitance change occurs can be calculated from the capacitance value data C _{1,1 to} C _{M, N.}

In FIG. 6B, as the contact object 8, a first contact object, a second contact object, and a third contact object are assumed. The first contact object may be a user's finger, the second contact object may be a gloved user's finger, and the third contact object may be a pen. In FIG. 6B, the contact object is estimated by the combination of the value of the peak capacity value data C _{PEAK and} the range in which the capacity change occurs.

Step S200 is the same as that in FIG. In step S200, when the threshold value TH is updated, in other words, when the peak capacity value data C _PEAK becomes small, the contact object 8 is not the first contact object (finger), that is, the second contact object (glove). Or a third contact object (pen).

Of the frame capacity value data C _{1,1 to} C _{M, N} , the number of data exceeding a certain threshold level corresponds to the range in which the capacity change occurs. Therefore, when the number of data exceeding the threshold value is equal to or smaller than the first predetermined value and the threshold value TH is equal to or smaller than the second predetermined value (Y in S208), the arithmetic processing unit 18 uses the pen as the contact object. It is determined that there is (S212). In other cases (N in S208), it is determined that the contact object is a glove (S210).

  The estimation algorithm of the contact object is an example, and other modified examples are also included in the present invention.

  If the contact object 8 can be estimated, the operation of the application software can be optimized according to the estimated contact object. For example, the application software switches the screen displayed on the LCD 9 according to the data OBJ. FIGS. 7A and 7B are diagrams showing the display screen of the LCD 9. FIG. 7A shows an example of a screen that accepts handwritten input of characters. When the data OBJ indicates that the contact object 8 is a finger (left figure), when the size of the handwriting input window is increased and the contact object 8 indicates that it is a pen (right figure), the handwriting input window Reduce the size.

  FIG. 7B shows an example of a screen that accepts character input by selecting an icon. When the data OBJ indicates that the contact object 8 is a pen (left figure), the icon size ICON is reduced, and when the contact object 8 indicates that the contact object 8 is a finger or a glove, the icon size ICON is increased.

  By generating the data OBJ as in the second embodiment, the contents of the display screen can be changed according to the data OBJ, and a comfortable input operation can be realized.

  Although the present invention has been described using specific words and phrases based on the embodiments, the embodiments are merely illustrative of the principles and applications of the present invention, and the embodiments are defined in the claims. Many modifications and arrangements can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Electronic device, 2 ... Input device, 4 ... Sensor part, 5 ... Shield electrode, 6 ... Panel controller, 8 ... Contact object, 9 ... LCD, 10 ... Capacity detection circuit, 12 ... C / V conversion circuit, 14 ... A / D conversion circuit, 16 ... peak detection unit, 18 ... arithmetic processing unit, 20 ... threshold value control unit, SE ... sensor electrode.

Claims (11)

A controller of a touch input device having a plurality of sensor electrodes whose capacitance changes according to a user's contact state,
A peak detector that receives capacitance value data indicating the capacitance of each of the plurality of sensor electrodes generated for each frame period, and determines peak capacitance value data having the largest capacitance;
An arithmetic processing unit that compares the peak capacity value data generated for each frame period with a threshold value and determines the presence or absence of user contact;
A threshold control unit for controlling the threshold;
With
When the peak capacity value data that is smaller than the current threshold value and larger than a predetermined minimum value is continuously detected over a predetermined number of frames, the threshold value control unit determines the threshold value as the threshold value. A controller, wherein an average value of the peak capacity value data obtained in a predetermined number of frames is updated to a value obtained by multiplying a predetermined coefficient K (0 <K <1).   2. The controller according to claim 1, wherein the threshold control unit returns the threshold to a predetermined initial value when detecting the peak capacity value data lower than the minimum value.   The controller according to claim 2, wherein the initial value is a midpoint between a maximum value and a minimum value that can be taken by the capacitance value data.   The said arithmetic processing part is comprised so that the data which show the contact thing which determined the contact thing which contacts a panel based on the said peak capacity | capacitance value data and the determined contact thing can be output. The controller according to any one.   When the threshold value is updated, the arithmetic processing unit determines that the contact object that contacts the panel is the first contact object, and when the threshold value is not updated, the contact object that contacts the panel is the first contact object. The controller according to claim 1, wherein the controller is determined to be other than the contact object.   The arithmetic processing unit determines a range in which a capacitance change occurs based on a plurality of the capacitance value data, determines a contact object that touches the panel according to the range, and indicates the determined contact object The controller according to any one of claims 1 to 3, wherein the controller is configured to be capable of outputting.   4. The method according to claim 1, wherein the arithmetic processing unit determines a contact object in contact with the panel according to a comparison result between the number of capacitance value data exceeding a predetermined threshold level and a predetermined value. 5. The controller described in Crab.   A touch input device comprising the controller according to claim 1.   An electronic apparatus comprising the controller according to claim 1. A method for controlling a touch input device having a plurality of sensor electrodes, each of which changes in capacitance according to a user's contact state,
Generating capacitance value data indicating the capacitance of each of the plurality of sensor electrodes for each frame period;
Determining peak capacitance value data having the largest capacitance;
Comparing the peak capacity value data with a threshold and determining the coordinates touched by the user;
Controlling the threshold;
With
Controlling the threshold comprises:
When the peak capacity value data smaller than the current threshold value and larger than a predetermined minimum value is continuously detected over a predetermined number of frames, the threshold value is obtained at the predetermined number of frames. A method of updating an average value of peak capacity value data to a value obtained by multiplying a predetermined coefficient K (0 <K <1).   The method of claim 10, wherein the step of controlling the threshold value returns the threshold value to a predetermined initial value when the peak capacity value data lower than the minimum value is generated.

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