KR102047976B1 - Circuit and method for controling of differential touch sensing system - Google Patents

Abstract

The present invention discloses a control circuit of a differential touch sensing system, the control circuit comprising: a labeling unit for performing a labeling process for converting a differential value into a labeling value; A palm region detector for detecting a palm region by scanning a change in the labeling value; A first operation of setting a forgetting count value in the unit blocks corresponding to the palm area; and updating the forgetting count value of the unit blocks defined as a palm area extended to a previous frame in an area outside the palm area. An oblivion calculator for performing an oblivion operation including two operations; And a palm region extension unit defining the unit blocks having the forgetting count value as the extended palm region.

Description

Control circuit and method of differential touch sensing system {CIRCUIT AND METHOD FOR CONTROLING OF DIFFERENTIAL TOUCH SENSING SYSTEM}

The present invention relates to a differential touch sensing system, and more particularly, to a control circuit and a method of a differential touch sensing system for detecting a change in a palm region caused by a palm touch, distinguished from a normal touch.

Recently, a display panel configured in a mobile device or the like employs many touch functions.

In this case, most display panels are implemented as flat panel display devices such as liquid crystal displays, and touch functions are implemented as touch panels combined with display panels.

The touch panel refers to a transparent switch panel having a function of operating a device or executing a program as a user presses text, an image, or an icon.

The touch panel may be configured to perform touch recognition in a capacitive manner, and as an example of a touch panel for implementing capacitive touch recognition, a "mutual capacitance touch sensing device" is disclosed as "US Patent Publication No. 2009/0091551". have.

A general touch sensing system is sometimes developed to sense in a differential manner in order to sense a correct capacitance.

When the sensing signal is driven in a differential manner, the touch sensing system has a strong characteristic of noise, and thus, an effect of improving touch sensitivity and sensing accuracy can be expected.

Recently, applications to which a touch sensing system is applied, such as a mobile device, have been developed to implement high functionality. Accordingly, the touch sensing system also needs to be improved to accurately recognize touch in order to support high functionality.

A general touch sensing system is implemented to recognize a touch by a finger or a touch pen as a normal touch.

In the touch recognition environment, the user may attempt to touch using a finger or a touch pen while the hand is in contact with the touch panel.

At this time, in addition to the touch area by the finger or the touch pen, the palm area may be recognized as a touch. Here, the palm region refers to an area in which the side of the palm or the hand is recognized by touching the touch panel, and usually has a larger area than the touch region by a finger or a touch pen.

The palm area acts as an obstacle in recognizing a normal touch, and a recognition error of the normal touch may occur due to the palm area.

Therefore, the touch sensing system needs to recognize the palm area accurately by distinguishing it from the normal touch.

In addition, the palm area may be reduced or enlarged according to the movement of the hand. If the palm area is reduced, the palm area may be mistaken for a normal touch.

An object of the present invention is to provide a control circuit and method of a differential touch sensing system capable of accurately distinguishing and recognizing a normal touch and a palm area.

Another object of the present invention is to provide a control circuit and a method of a differential touch sensing system capable of preventing a mistake in a reduced palm area as a normal touch in the process of changing a palm area according to a movement of a hand.

The control circuit of the differential touch sensing system according to the present invention includes: a labeling unit performing a labeling process of converting a differential value for each unit block of a sensed frame into a labeling value; A palm region detector for detecting a palm region by scanning a change in the labeling value corresponding to each sensing line of the frame; A first operation of setting a forgetting count value in the unit blocks corresponding to the palm area; and updating the forgetting count value of the unit blocks defined as a palm area extended in a previous frame in an area outside the palm area. An oblivion calculator for performing an oblivion operation including two operations; And a palm region extension unit defining the unit blocks having the forgetting count value as the extended palm region after performing the forgetting operation.

A control method of a differential touch sensing system according to the present invention includes: setting a forgetting count value for a palm area detected in a current frame; Updating the forgetting count value of the extended palm area defined in the previous frame except the palm area; And defining an area in which the forgetting count value is maintained by the setting and updating as the extended palm area.

According to the present invention, the normal touch and the palm area can be distinguished, and thus the effect of performing accurate touch recognition can be expected.

In addition, the present invention detects the change in the palm area according to the movement of the hand and maintains the forgetful count value for a certain period of time to manage the extended palm area to prevent the mistake of the palm area as a normal touch to implement accurate touch recognition effect You can expect.

1 is a block diagram illustrating a preferred embodiment of a differential touch sensing system in accordance with the present invention.
2 is a block diagram showing a preferred embodiment of the control circuit of FIG.
3 is a flow chart showing a preferred embodiment of the control method performed by FIG.
4 is a waveform diagram illustrating sensing data in which differential values are integrated.
5 is a waveform diagram illustrating a change in a differential value.
6 is a map of labeling values for explaining a method of detecting a palm area.
7 is a view for explaining a change in forgetting count value for each frame.
8 is a view for explaining a change in the palm region according to the movement of the hand.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. The terms used in the present specification and claims are not to be construed as being limited to ordinary or dictionary meanings, but should be interpreted as meanings and concepts corresponding to the technical matters of the present invention.

The embodiments described in the specification and the configuration shown in the drawings are preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, various equivalents and modifications that can replace them at the time of the present application are There may be.

The control circuit and method of the differential touch sensing system according to the present invention discloses a technique for sensing a palm area on a touch panel and recognizing a palm area that is enlarged or reduced according to the movement of a hand separately from a normal touch.

The differential touch sensing system configured as an embodiment according to the present invention may be configured as shown in FIG.

Referring to FIG. 1, the differential touch sensing system may include a PWM controller 10, a driving circuit 12, a touch panel 14, a sensing circuit 16, an image buffer 18, and a control circuit 20. have.

The PWM controller 10 provides a driving pulse for periodic sensing.

The drive circuit 12 provides a drive signal synchronized with the drive pulse to the touch panel 14. In this case, the driving signal may be provided to the touch panel 14 in a differential manner.

The touch panel 14 includes a plurality of drive lines (not shown) and a plurality of sensing lines (not shown). The plurality of driving lines and the plurality of sensing lines may be variously formed according to the intention of the manufacturer, and may be formed to intersect or side by side to share the capacitance formed in the spaces which are usually spaced apart.

Therefore, a driving signal is applied to the driving line, and a sensing signal is output from the sensing line. When a change in capacitance occurs by touch, the sensing signal outputs a sensing signal reflecting the change in capacitance.

That is, the touch panel 14 is configured to output a sensing signal corresponding to a driving signal that is periodically applied in a differential manner.

The sensing circuit 16 transmits a sensing signal applied in a differential manner from the touch panel 14 to the image buffer 18. Here, the sensing circuit 16 may be configured to perform a function such as amplifying the sensing signal or filtering the noise.

The image buffer 18 may be configured to include a frame unit storage capable of accommodating the full frame of the touch panel 14, and converts and stores an analog signal transmitted from the sensing circuit 16 to have a digital value. And then output. That is, the image buffer 18 outputs sensing data as a digital signal.

The control circuit 20 receives sensing data which is a digital signal output from the image buffer 18. The sensing data received by the control circuit 20 may be expressed in the form of raw data for a frame of the touch panel 14. The raw data refers to data having a differential value in which digital values are mapped by being divided by positions of a plurality of scan lines with respect to the frame area of the touch panel 14.

The control circuit 20 of FIG. 1 may be implemented with firmware for calculating coordinates in the chip.

The control circuit 20 may include a function for realizing touch recognition, calculating coordinates for the touch, detecting noise, and the like.

The control circuit 20 configured as an embodiment according to the present invention may have a function for distinguishing a palm area from a normal touch and a function for recognizing a change in a palm area according to the movement of a hand.

To this end, the control circuit 20 sets a forgetting count value for the palm region detected in the current frame, updating the forgetting count value of the region except the palm region among the extended palm regions defined in the previous frame; And defining the area in which the forgetting count value is maintained by the setting and updating as the extended palm area.

The control circuit 20 may further include detecting a palm area, and the detecting of the palm area may include a labeling step of converting differential values of the current frame into a labeling value and each sensing of the current frame. And detecting the palm area by scanning a change in the labeling value corresponding to a line.

In order to implement the above functions, the control circuit 20 may be exemplified as having the configuration as shown in FIG. 2.

Referring to FIG. 2, the control circuit 20 may include a labeling unit 30, a palm region detector 32, an oblivion calculator 34, and a palm region extension 36.

The labeling unit 30 receives sensing data having a differential value for each coordinate, that is, for each unit block, in the image buffer 18, and performs a labeling process of converting the differential value for each unit block of a frame into a labeling value. That is, the labeling unit 30 obtains the labeling region of FIG. 5 from the differential value of FIG. 5 by performing the labeling S2 of FIG. 3. Here, the sensing data is raw data to which differential values are mapped.

The labeling process includes mapping the labeling values of the unit blocks having a differential value greater than or equal to a predetermined threshold for each unit block of the frame.

The labeling area refers to an area having a predetermined or more positive slope as shown in FIG. 4 in which the differential value of FIG. 5 is integrated in the scan direction.

The threshold value is preferably set to a positive value, and the labeling value is preferably obtained by obtaining an area having a value larger than the threshold value.

A process of obtaining the labeling region will be described with reference to FIG. 5.

The sensing data received from the image buffer 18 is row data in which differential values are mapped for each unit block of the frame, and the sensing data has a differential value changed in the scan direction for each sensing line as shown in FIG. 5.

 Differential values of the sensing data may have a wide range of patterns in the scan direction corresponding to the palm touch sensed by a large area. That is, the differential values of the sensing data have a large positive value in the scan direction like the area P, and then have a small negative value distribution, a small variable range, and a large negative value again. Can have

Thresholds for the differential values of FIG. 5 may be set for labeling. Labeling is a process of grouping regions having differential values greater than or equal to a threshold as shown in FIG. 5 into a single label. As a result, mapped labeling values for a frame may be obtained as shown by a dotted line in FIG. 6.

 In this case, the threshold value may be applied according to the manufacturer's intention in consideration of the characteristics of the differential values. In the case of Figure 4 illustrates that the threshold '10' is applied.

In general, the labeling process can reduce a large amount of computation by performing a limited region having a positive slope greater than or equal to a predetermined number instead of performing a large number of positive values having a predetermined threshold or greater in FIG. 4.

Meanwhile, the palm region detector 32 detects the palm region by extending the labeling region shown in FIG. 5 corresponding to each sensing line of the frame in the scan direction. That is, the palm region detector 32 scans the labeling value of FIG. 3 and determines the palm region (S4).

More specifically, the palm region detector 32 determines whether the labeling values are in a region equal to or greater than a preset palm region threshold value as shown in FIG. 5 in the scan direction. When the determination condition is satisfied, the palm area detection unit 32 determines that the palm block includes the unit blocks satisfying the determination condition.

The operation of the palm region detection unit 32 will be described in more detail with reference to FIG. 5.

First, the palm region detector 32 expands the palm region by detecting a region of the palm region threshold '-10' or more preset in the scan direction based on the labeling region as shown in FIG. 5.

 In the example of FIG. 5, the area P changes the labeling value in the order of '15, 15, 25, 5, 8, -8, 6, 2, -2, 9, -5 'with respect to the scanning direction based on the labeling area. Therefore, it satisfies the area above the palm area threshold.

Further, in determining the palm region, the palm region detector 32 sequentially scans the unit palm regions UP1, UP2, UP3, UP4, and UP5 having unit areas of horizontal and vertical sizes, as shown in FIG. 6, in the scanning direction. You can judge. The palm region detector 32 may detect a set of unit palm regions UP1, UP2, UP3, UP4, and UP5 as palm regions.

In the case of FIG. 6, the unit palm areas UP1, UP2, UP3, UP4, and UP5 are illustrated as including three unit blocks each having a horizontal and a vertical size.

The palm region detector 32 determines the unit palm regions UP1, UP2, UP3, UP4, and UP5 to the last position maintained in the scan direction based on the labeling region satisfying the variable range.

The palm region detection unit 32, like the unit palm regions UP1 and UP5, even if only one or more unit blocks determined to be included in the palm region exist, other adjacent unit blocks are also included in the unit palm regions UP1 and UP5. Judging by.

That is, in the unit palm area UP5, values (-17, -15, -16, -23, -25, and -22) which are not determined to be palm areas are present in the same sensing line or another sensing line. However, in the unit palm area UP5, there are values '5, 3, -3' that are determined to be included in the palm area in the scanning direction from the labeling area. Therefore, the unit palm area UP5 may be determined to include a unit block in which '-5, 3, -3' exists and the remaining four unit blocks adjacent thereto.

 In addition, in the case of FIG. 6, the palm region detection unit 32 determines the number of the unit palm regions with respect to the set of those in which the unit palm regions UP1, UP2, UP3, UP4, UP5 are sequentially determined in the scanning direction based on the labeling region. When counting to maintain more than a certain number of thresholds to determine the final palm area. This is to distinguish a finger from a palm as shown in F and P of FIG. 8.

As a result, the palm region detection unit 32 described above can detect the region P as the palm region as shown in FIG. In addition, the region F sequentially having a small region while the positive region and the negative region have a large differential value with respect to the scan direction may be detected as a normal touch.

As described above, the embodiment of the present invention can accurately recognize the normal touch and the palm area, thereby improving the accuracy of the touch recognition.

Meanwhile, the forgetting operation unit 34 performs the forgetting operation including the first operation and the second operation.

The first operation corresponds to step S6 of FIG. 3 and sets a forgetting count value in the unit blocks detected in the palm area. The second operation corresponds to S8 of FIG. 3 and updates the forgetting count values of the unit blocks defined by the palm region extended to the previous frame in the region outside the palm region.

In the first operation of the forgetting calculator 34, the setting means replacing the forgetting count starting value with the forgetting count value. The maximum value of the forgetting count start value set as the forgetting count range may be applied. 7 illustrates an example of applying the forgetting count range from 0 to 10 and applying the forgetting count start value to 10. FIG.

In addition, in the second operation of the forgetting calculator 34, updating means reducing the forgetting count value.

Meanwhile, the palm region extension unit 36 defines unit blocks having an oblivion count value as an extended palm region after the forgetting operation. That is, the palm region extension unit 36 performs step S10 of FIG. 3 to define an area having an '0' or more as an extended palm region without forgetting the count value.

The operations of the forgetting operation unit 34 and the palm region expansion unit 36 will be described in detail with reference to FIGS. 7 and 8.

The forgetting calculator 34 may perform the forgetting operation on the area P first detected as the palm area as shown in FIG. 7A.

The forgetting operation of FIG. 7A includes a first operation of setting the forgetting count value in the unit blocks included in the area P. As a result, the forgetting count start value '10' is set in the unit blocks of the area P. As shown in FIG. do.

The forgetting operation of FIG. 7A does not include the second operation for updating the forgetting count value because there is no extended palm area defined in the previous frame.

In step (a) of FIG. 7, the palm region extension unit 36 defines unit blocks in which the forgetting count start value '10' is set as the extended palm region.

Thereafter, the forgetting operation unit 34 repeatedly performs the forgetting operation in response to a result of labeling the sensing data of the periodically input frames.

As shown in FIG. 7B, the forgetting calculator 34 performs a first operation of setting the forgetting count start value '10' for the unit blocks included in the area Pa detected as the palm area in the current frame. By the first operation, the forgetting count start value '10' is collectively set in the unit blocks included in the area Pa.

The forgetting calculator 34 performs a second operation on the unit blocks of the area A1 excluded from the area Pa defined as the palm area in FIG. 7B to update the forgetting count value. That is, the forgetting calculator 34 decreases the forgetting count values set in the unit blocks of the area A1 by one step. Accordingly, the forgetting count value of the area A1 is decreased from '10' to '9'.

When the forgetting operation by the forgetting operation unit 34 is completed in the step of FIG. 7 (b), the palm area extension unit 36 extends the areas in which the forgetting count value is not destroyed by the forgetting operation and is maintained at '0' or more. Defined by the palm area. That is, in FIG. 7B, the region Pa and the region A1 are defined as extended palm regions.

The above-described forgetting operation is also applied to the step of FIG. 7 (c), and the forgetting count start value '10' is set in the area Pb detected as the palm area for the current frame in FIG. 7 (c) and excluded from the area Pb. The forgetting count value set in the unit blocks of the areas A1 and A2 is decreased by one step. In FIG. 7C, the region Pb and the regions A1 and A2 are defined as extended palm regions.

As described above, the forgetting operation by the forgetting operation unit 34 and the extended palm area definition by the palm area extension unit 36 are performed in response to the periodically sensed frame.

In this process, if a partial region defined as the palm region extended by the movement of the hand is not continuously detected as the palm region in a subsequent frame, the forgetting count values of the unit blocks of the corresponding region are equal to the area A1 of FIG. Likewise, it reaches '0' and is destroyed.

That is, the area or unit block detected as the palm area is not recognized as the extended palm area until it is detected as the palm area again unless it is detected as the palm area again until the forgetting count value disappears.

Therefore, according to the embodiment of the present invention, the palm area extended in response to the movement of the hand is enlarged and reduced and the forgetting count value is managed, thereby preventing the palm area from being misjudged by the normal touch.

More specifically, the palm area is recognized as the area P of FIG. 8 (a), but is recognized as the areas P1 and P2 of FIG. 8 (b) by the movement of the hand, and then the area P3 of FIG. 8 (c). Can be.

In this case, the areas P1 and P2 of FIG. 8B may have a small area and may be mistaken for a normal touch.

However, in the embodiment according to the present invention, the area P recognized as the palm area in FIG. 8 (a) is defined as the extended palm area, and the unit defined as the palm area P extended in the previous frame in FIG. 8 (b). The forgetting count value of the blocks is not destroyed but remains reduced.

Therefore, even when regions P1 and P2 are not recognized as palm regions in FIG. 8B, the regions P1 and P2 are recognized as extended palm regions P by maintaining the forgetting count value. As a result, the regions P1 and P2 of FIG. 8B are recognized as extended palm regions without being mistaken as a normal touch.

Therefore, in the differential touch sensing system, the palm area can be recognized by distinguishing it from the normal touch, and since the palm area is temporarily prevented from being mistaken as the normal touch, accurate touch recognition can be performed.

10: PWM control unit 12: driving circuit
14 touch panel 16: sensing circuit
18: image buffer 20: control circuit
30: labeling unit 32: palm area detection unit
34: oblivion calculation unit 36: palm area expansion unit

Claims (16)

A labeling unit configured to perform a labeling process of converting a differential value for each unit block of the sensed frame into a labeling value;
A palm region detector for detecting a palm region by scanning a change in the labeling value corresponding to each sensing line of the frame;
A first operation of substituting a forgetting count starting value into a forgetting count value in the unit blocks corresponding to the palm area of the current frame and a palm area extended to a previous frame in an area beyond the palm area of the current frame; An oblivion operation unit configured to perform an oblivion operation including a second operation of performing an update to decrease the forgetful count value of the unit blocks; And
The unit blocks for which the forgetting count start value is set as the forgetting count value by the first operation or the forgetting count value is not reached by the second operation after the forgetting operation is performed; Control area of the differential touch sensing system comprising a; palm area extension defined by the extended palm area. According to claim 1,
The labeling process may include mapping a labeling value of unit blocks having a differential value equal to or greater than a predetermined threshold value to each unit block of the frame. The method of claim 2,
And the threshold value is set to a positive value, and the labeling value is obtained by expressing a value larger than the threshold value as a positive value. According to claim 1,
And the palm region detector determines that the palm region includes the unit block having a value larger than a predetermined threshold value set as a negative value with respect to a scan direction based on a labeled region. The method of claim 4, wherein
The palm region detection unit sequentially determines a unit palm region having a unit area having a horizontal and vertical size determined in the scanning direction, and detects a set of the unit palm regions as the palm region, wherein the unit palm region is the palm region. The control circuit of the differential touch sensing system defined by the same size for one or more of the unit blocks determined to include in. The method of claim 5,
And the palm region detector counts the number of the unit palm regions, and determines that the palm region is the palm region that is distinguished from the finger region when the number of the unit palm regions is greater than or equal to a predetermined number. delete According to claim 1,
And the forgetting count start value is a maximum value among the values set as the forgetting count range. delete delete delete delete delete delete delete delete

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