CN102156562A - Object sensing device, touch sensing system and touch sensing method - Google Patents

Abstract

An object sensing device comprises an object sensing unit, a signal selection unit, at least one signal sensing unit and a control unit. The object sensing unit is used for outputting a plurality of sensing signals. The signal selection unit is used for selecting at least one of the sensing signals as a signal to be tested and selecting at least one of the unselected sensing signals as a reference signal. The signal sensing unit is used for outputting a difference signal according to the signal to be detected and the reference signal. The control unit is used for judging at least one object position relative to the object sensing unit according to the difference signal. In addition, a touch sensing device and a method thereof are also provided.

Description

Object sensing device, touch sensing system and touch sensing method

technical field

The present invention relates to a sensing device and its method, and in particular to an object sensing device and its method.

Background technique

In today's information age, human beings are increasingly dependent on electronic products. Notebook computers, mobile phones, personal digital assistants (personal digital assistants, PDAs), digital walkmans and other electronic products have become indispensable application tools in the life and work of modern people. The above-mentioned electronic products all have an input interface for inputting the user's required command, so that the internal system of the electronic product automatically executes the command. Currently, the most widely used input interface devices include a keyboard and a mouse.

For users, using traditional input interfaces such as keyboards and mice will undoubtedly cause considerable inconvenience in some occasions. In order to solve such problems, manufacturers have begun to configure a touch input interface such as a touch pad or a touch panel on the electronic device, and then replace it with a touch pad or a touch panel. Function of the keyboard or mouse. As far as the touch input interface is concerned, most of the current users use the contact or sensing behavior generated between the finger or the stylus and the touch input interface to perform the click action. As far as the capacitive touch input interface is concerned, the feature of multi-touch provides a more user-friendly operation mode, so that the capacitive touch panel is gradually favored by the market.

However, in the capacitive touch input interface, if a single-ended sensing circuit is used to measure the sensing change of the capacitor under test, the capacitance value of the capacitor under test must be measured and stored as a baseline. . Afterwards, the substrate is subtracted from the actual measured capacitance value to obtain the induced change of the capacitance to be measured. At the same time, the measurement reference value of the capacitance to be measured in the single-ended sensing circuit is fixed, which makes it unable to effectively offset the noise from the outside world, thereby making the noise-to-signal ratio (Noise-to-Signal Ratio) of the single-ended sensing circuit , NSR) cannot be effectively improved.

Contents of the invention

The invention provides an object sensing device, which can dynamically adjust the measurement reference value and effectively improve its noise-to-signal ratio.

The invention provides a touch sensing system, which can dynamically adjust the measurement reference value and effectively improve its noise-to-signal ratio.

The invention provides a touch sensing method, which can dynamically adjust the measurement reference value and effectively improve the noise-to-signal ratio of the sensing system.

The invention provides an object sensing device, which includes an object sensing unit, a signal selection unit, at least one signal sensing unit and a control unit. The object sensing unit is used for outputting a plurality of sensing signals. The signal selection unit is used for selecting at least one of the sensing signals as a signal to be tested, and selecting at least one of the unselected sensing signals as a reference signal. The signal sensing unit is used for outputting a difference signal according to the signal to be tested and the reference signal. The control unit is used for judging an object position relative to the object sensing unit according to the difference signal.

In an embodiment of the present invention, the above-mentioned control unit includes an analog-to-digital converter and a controller. The analog-to-digital converter is used to convert the difference signal into a digital signal. The controller is used for judging the position of the object relative to the object sensing unit according to the digital signal.

In an embodiment of the present invention, the above-mentioned signal selection unit selects at least two different sensing signals from unselected sensing signals during a first sensing period and a second sensing period respectively. signal as a reference signal.

In an embodiment of the present invention, there are P sensing signals mentioned above. The signal selection unit selects the Nth sensing signal as the signal to be tested, and selects the (N+K)th sensing signal and the (N-K)th sensing signal as the reference signal, wherein P, N, and K are each positive Integer, 1<N<P, 3≤K+N≤P, 1≤K-N≤(P-2).

In an embodiment of the present invention, the above-mentioned signal selection unit selects at least two or more signals from the sensing signals as the signals to be tested, and selects at least two or more signals from the unselected sensing signals as the reference signals, And each signal sensing unit receives a corresponding signal to be tested and a corresponding reference signal to output a corresponding difference signal.

In an embodiment of the present invention, the signal under test received by each signal sensing unit is different from the other signals under test received by other signal sensing units.

In an embodiment of the present invention, each signal sensing unit receives the same corresponding signal to be tested during a first sensing period and a second sensing period.

In an embodiment of the present invention, each signal sensing unit receives different reference signals during the first sensing period and the second sensing period.

In an embodiment of the present invention, the above-mentioned control unit receives a plurality of difference signals, and determines the position of the object relative to the object sensing unit according to the received plurality of difference signals.

In an embodiment of the present invention, the above-mentioned control unit includes a plurality of analog-to-digital converters and a controller. Each analog-to-digital converter is used for receiving a corresponding difference signal and converting it into a corresponding digital signal. The controller is used for receiving multiple digital signals, and judging the position of the object relative to the object sensing unit according to the multiple received digital signals.

In an embodiment of the present invention, the above-mentioned object sensing device further includes a driving unit for driving the object sensing unit to output a sensing signal.

The invention provides a touch sensing system, which includes a touch input interface, a signal selection unit, at least one signal sensing unit and a control unit. The touch input interface includes a plurality of touch sensors for outputting a plurality of sensing signals according to a touch action. The signal selection unit is used for selecting at least one of the sensing signals as a signal to be tested, and selecting at least one of the unselected sensing signals as a reference signal. The signal sensing unit is used for outputting a difference signal according to the signal to be tested and the reference signal. The control unit is used for judging the position where the touch action occurs on the touch input interface according to the difference signal.

In an embodiment of the present invention, the above-mentioned control unit includes an analog-to-digital converter and a controller. The analog-to-digital converter is used to convert the difference signal into a digital signal. The controller is used for judging the position where the touch action occurs on the touch input interface according to the digital signal.

In an embodiment of the present invention, the above-mentioned signal selection unit selects at least two different sensing signals from unselected sensing signals during a first sensing period and a second sensing period respectively. signal as a reference signal.

In an embodiment of the present invention, there are P sensing signals mentioned above. The signal selection unit selects the Nth sensing signal as the signal to be tested, and selects the (N+K)th sensing signal and the (N-K)th sensing signal as the reference signal, wherein P, N, and K are each positive Integer, 1<N<P, 3≤K+N≤P, 1≤K-N≤(P-2).

In an embodiment of the present invention, the above-mentioned signal selection unit selects at least two or more signals from the sensing signals as the signals to be tested, and selects at least two or more signals from the unselected sensing signals as the reference signals, And each signal sensing unit receives a corresponding signal to be tested and a corresponding reference signal to output a corresponding difference signal.

In an embodiment of the present invention, the signal under test received by each signal sensing unit is different from the other signals under test received by other signal sensing units.

In an embodiment of the present invention, each signal sensing unit receives the same corresponding signal to be tested during a first sensing period and a second sensing period.

In an embodiment of the present invention, each signal sensing unit receives different reference signals during the first sensing period and the second sensing period.

In an embodiment of the present invention, the above-mentioned control unit receives a plurality of difference signals, and determines that the touch action occurs at the position of the touch input interface according to the received plurality of difference signals.

In an embodiment of the present invention, the above-mentioned control unit includes a plurality of analog-to-digital converters and a controller. Each analog-to-digital converter is used for receiving a corresponding difference signal and converting it into a corresponding digital signal. The controller is used for receiving multiple digital signals, and judging the position where the touch action occurs on the touch input interface according to the received multiple digital signals.

In an embodiment of the present invention, the above-mentioned touch sensing system further includes a driving unit, which is used to drive the touch sensor to output a sensing signal.

The invention provides a touch sensing method, which is suitable for a touch sensing system, wherein the touch sensing system includes a touch input interface. The touch sensing method includes the following steps. A plurality of sensing signals are generated according to a touch action. At least one of the sensing signals is selected as a signal to be tested. At least one of the unselected sensing signals is selected as a reference signal. A difference signal is generated according to the signal to be tested and the reference signal. According to the difference signal, it is judged that the touch action occurs at the position of the touch input interface.

In an embodiment of the present invention, the above-mentioned touch sensing method further includes the following steps. The difference signal is converted into a digital signal. According to the digital signal, it is judged that the touch action occurs at the position of the touch input interface.

In an embodiment of the present invention, in the step of selecting a reference signal, select at least two different signals from unselected sensing signals during a first sensing period and a second sensing period respectively The sensing signal is used as a reference signal.

In an embodiment of the present invention, the above-mentioned sensing signal has P sensing signals, and in the step of selecting the signal to be tested, the Nth sensing signal is selected as the signal to be tested. In the step of selecting the reference signal, the (N+K)th sensing signal and the (N-K)th sensing signal are selected as reference signals, wherein P, N, and K are each a positive integer, 1<N<P, 3≤K+N≤P, 1≤K-N≤(P-2).

In an embodiment of the present invention, the above touch sensing system further includes a plurality of signal sensing units. In the step of selecting the signal to be tested, at least two or more sensing signals are selected as the signal to be tested. In the step of selecting a reference signal, at least two or more of the unselected sensing signals are selected as reference signals. In the step of generating a difference signal according to the signal to be tested and the reference signal, each signal sensing unit receives the corresponding signal to be tested and the corresponding reference signal to output a corresponding difference signal.

In an embodiment of the present invention, the signal under test received by each signal sensing unit is different from the other signals under test received by other signal sensing units.

In an embodiment of the present invention, each signal sensing unit receives the same corresponding signal to be tested during a first sensing period and a second sensing period.

In an embodiment of the present invention, each signal sensing unit receives different reference signals during the first sensing period and the second sensing period.

In an embodiment of the present invention, in the step of determining that the touch action occurs at the position of the touch input interface, it is determined that the touch action occurs at the position of the touch input interface according to a plurality of difference signals.

In an embodiment of the present invention, the above touch sensing method further includes generating a driving signal to drive the touch sensor to output a sensing signal after receiving the driving signal.

Based on the above, in an embodiment of the present invention, the signal selection unit selects at least one reference signal from multiple sensing signals as the measurement reference value of the signal to be measured, which can effectively offset the noise from the outside world, thereby improving its noise signal Compare. In addition, in different sensing periods, the signal selection unit selects different reference signals to achieve the purpose of dynamically adjusting the measurement reference value.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic block diagram of a touch sensing system according to an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram of the touch input interface of FIG. 1 .

FIG. 3 is a schematic block diagram of a touch sensing system according to another embodiment of the present invention.

FIG. 4 is a schematic block diagram of a touch sensing system according to another embodiment of the present invention.

FIG. 5 shows that the signal selection unit selects different sensing signals during different sensing periods and transmits them to corresponding signal sensing units as reference signals.

FIG. 6 shows that the signal selection unit selects different sensing signals during different sensing periods and transmits them to corresponding signal sensing units as reference signals.

FIG. 7 is a flowchart of steps of a touch sensing method according to an embodiment of the present invention.

[Description of main component symbols]

100, 300, 400: touch sensing system

110, 310, 410: capacitive sensing device

112, 312, 412: signal selection unit

114, 314, 414(1)~414(k): signal sensing unit

120, 320, 420: touch input interface

122: Drive line

124: Sensing line

130, 330, 430: control unit

132, 332, 432(1)～432(k): Analog-to-digital converter

134, 334, 434: Controller

S700, S702, S704, 706: steps

Y ₁ -Y _p : Sensing signal

X ₁ -X _q : Drive signal

S ₁ -S _k : signal to be tested

R ₁ -R _k : Reference signal

T ₁ -T _k : Sensing period

C(1)-C(p): Sensing Capacitance

ΔC: capacitance change

Detailed ways

In the capacitive touch input interface, the capacitance value of the sensing capacitor is determined according to whether the position on the sensing capacitor corresponding to the touch input interface is touched. When the sensing capacitor is touched corresponding to the position on the touch input interface, the touched object will generate a corresponding capacitance change, and form a capacitance to be measured with the sensing capacitor.

In the embodiment of the present invention, besides the capacitance to be measured, capacitance values of other sensing capacitors can be used as reference values when measuring the capacitance to be measured. Therefore, after comparing the capacitance value to be measured with the reference capacitance value, the touch position of the touch object corresponding to the touch input interface can be determined.

In the following embodiments, a touch panel will be used as an exemplary embodiment of the touch input interface. Those skilled in the art should know that the touch panel is not used to limit the touch input interface of the present invention. At the same time, the present invention is not limited to the touch-sensitive input interface, any input interface in the form of capacitive sensing is the scope of protection of the present invention.

FIG. 1 is a schematic block diagram of a touch sensing system according to an embodiment of the present invention. Please refer to FIG. 1. In this embodiment, the touch sensing system 100 includes a capacitive sensing device 110, a touch input interface 120 and a control unit 130, wherein the touch input interface 120 is, for example, a touch panel of a display. Or other touch panel with touch sensing function, which includes a plurality of sensing capacitors for outputting a plurality of sensing signals Y ₁ -Y _p .

FIG. 2 is a schematic circuit diagram of the touch input interface 120 in FIG. 1 . Please refer to FIG. 1 and FIG. 2 at the same time. In this embodiment, the capacitance value of the sensing capacitor is determined according to whether the position on the sensing capacitor corresponding to the touch input interface is touched. Taking the sensing capacitance C(n) as an example, when the sensing capacitance C(n) is touched corresponding to the position on the touch input interface, the touched object will generate a corresponding capacitance change ΔC. At this time, the sensing capacitance C(n) and the capacitance change ΔC form a capacitance to be measured C(n)+ΔC, and a signal to be measured Y _n is output through the corresponding sensing line 124 . Then, the capacitance value of the capacitance to be measured C(n)+ΔC can be sensed by the capacitance sensing device 110 to obtain its change. Afterwards, the control unit 130 can determine the capacitance to be measured corresponding to the touch position on the touch input interface according to the change. That is to say, the control unit 130 determines that the touch action occurs at the position of the object sensing unit 120 according to the change.

It is worth noting that in this embodiment, except for the capacitance to be measured C(n)+ΔC, the capacitance values of other sensing capacitances can be used as reference signals when measuring the capacitance to be measured, so as to effectively offset the external noise, thereby increasing its noise-to-signal ratio.

In detail, taking a mutual capacitance type touch sensing system as an example, during operation, the capacitance to be measured on the touch input interface 120 receives driving from a driving unit (not shown) through a corresponding driving line. The signals X ₁ -X _q generate sensing signals Y ₁ -Y _p on the corresponding sensing lines. Wherein, p and q are each a positive integer, and 1<p, 1<q. For example, when driven, the driving signal X _m applied to the driving line 122 can be coupled to the sensing line 124 crossing it through the sensing capacitor C(n), thereby generating a sensing signal Y _n on the sensing line 124 . Wherein, n and m are each a positive integer, and 1≤n≤p, 1≤m≤q.

Therefore, during operation, by applying the driving signal X _m to the driving line 122 , the capacitance sensing device 110 can obtain the function relationship of the capacitance value distribution of the sensing capacitances C(1)-C(p).

Therefore, when a touch object (such as a finger or a stylus) approaches or touches the sensing capacitance C(n) corresponding to the position on the touch input interface 120, it will generate a corresponding capacitance change ΔC, thereby changing the Functional relationship. Afterwards, the touch sensing system 100 can determine the capacitance to be measured C(n)+ΔC corresponding to the touch position on the touch input interface 120 through the capacitance sensing device 110 and the control unit 130 .

Please continue to refer to FIG. 1 , in the present embodiment, the capacitance sensing device 110 includes a signal selection unit 112 and a signal sensing unit 114 . The control unit 130 includes an analog-to-digital converter 132 and a controller 134 .

The signal selection unit 112 is used for receiving the sensing signals Y ₁ -Y _p , and selecting at least one signal to be tested and at least one reference signal from the sensing signals Y ₁ -Y _p . Afterwards, the signal selection unit 112 transmits the selected signal to be tested and the reference signal to the signal sensing unit 114 for a difference comparison.

For example, during a first sensing period, the signal selection unit 112 selects to transmit the sensing signals Y _n , Y _n+k to the signal sensing unit 114 for difference comparison. Here, k is a positive integer, and 1≤n≤(p-1), 2≤(n+k)≤p. Taking k=1 as an example, the signal selection unit 112 selects the sensing signal Y _n+1 adjacent to the sensing signal Y _n as a reference signal when measuring the capacitance to be measured, and outputs it to the signal sensing unit 114 and The sensing signal _Yn is compared with the difference. Then, after the difference comparison is completed, the signal sensing unit 114 generates a difference signal and outputs it to the control unit 130 . That is to say, the control unit 130 is configured to determine that the touch action occurs at the position of the object sensing unit 120 according to the difference signal.

Therefore, in this embodiment, in addition to the signal to be measured Y _n , the signal selection unit 112 selects the sensing signal Y _n+k from the unselected sensing signals as the reference signal when measuring the capacitance to be measured, which can effectively The noise from the touch input interface 120 is offset to improve its noise-to-signal ratio.

That is to say, the noise from the touch input interface 120 can be regarded as common mode noise (commonmode noise), so by selecting at least one sensing signal from unselected sensing signals as the A reference signal that suppresses common-mode noise in the sensing circuit to improve the noise-to-signal ratio of the sensing system.

It should be noted that this embodiment takes the signal selection unit 112 as an example to select the sensing signals Y _n and Y _n+k , but the present invention is not limited thereto. In other embodiments, the signal selection unit 112 may select any sensing signal Y _m (not shown) from the unselected sensing signals as a reference signal when measuring the capacitance to be measured, so as to effectively offset the Control the noise on the input interface 120, where 1≤m≤p.

Therefore, during the first sensing period, when the sensing capacitor C(n) has a capacitance change ΔC due to being touched, the control unit 130 can calculate the corresponding The position on the touch input interface 120 .

In addition, during a second sensing period following the first sensing period, the signal selection unit 112 may select to transmit the sensing signals Y _n , Y _nk (not shown) to the signal sensing unit 114 for difference comparison. Here, 2≤n≤p, 1≤(nk)≤(p-1). For example, when k=1, it means that the signal selection unit 112 selects the sensing signal Y n ₋₁ adjacent to the sensing signal Y _n as a reference signal when measuring the capacitance to be measured.

That is to say, for the same sensing signal Y _n , the signal selection unit 112 can select different sensing signals (ie, Y _n+k , Y _nk ) is used as a reference signal when measuring the capacitance to be measured, so as to achieve the purpose of dynamically selecting the reference signal.

It should be noted that, during adjacent sensing periods, the signal selection unit 112 is not limited to selecting symmetrical sensing signals Y _n+k and Y _nk as reference signals for measuring the capacitance to be measured, which can be used in adjacent During the sensing period, a different sensing signal is selected from unselected sensing signals as a reference signal when measuring the capacitance to be measured.

In addition, in other embodiments, for the same sensing signal Y _n , the signal selection unit 112 may also select the same sensing signal from unselected sensing signals as the quantity during adjacent sensing periods. The reference signal when measuring the capacitance under test.

In this embodiment, the signal sensing unit 114 is, for example, a comparator (not shown), used to receive and compare the signal under test and the reference signal transmitted by the signal selection unit 112 to generate a corresponding difference signal to the control Unit 130, but the present invention is not limited thereto. In another embodiment, the signal sensing unit 114 is, for example, a differential amplifier. When the signal sensing unit 114 is a differential amplifier, it can compare and amplify the voltage difference between the signal to be tested and the reference signal, and output it to the control unit 130 to improve the accuracy of determining the touch position. In addition, in another embodiment, the signal sensing unit 114 can also be implemented by an integrator. At this time, the integrator can integrate and amplify the voltage difference between the signal to be measured and the reference signal, so as to output a corresponding difference signal to the control unit 130 .

In this embodiment, the difference signal generated by the signal sensing unit 114 is, for example, an analog signal. Therefore, after receiving the analog signal, the analog-to-digital converter 132 converts it into a digital signal. Next, the controller 134 performs a digital operation on the digital signal to obtain a touch position on the touch input interface 120 corresponding to the measured capacitance C(n)+ΔC. That is to say, the controller 134 can determine that the touch action occurs at the position of the object sensing unit 120 according to the difference signal.

It should be noted that in this embodiment, the touch sensing system 100 is an example of a mutual capacitance touch system, but the present invention is not limited thereto. In other embodiments, the touch sensing system 100 may also be a self-capacitive touch system or any other form of touch system.

In addition, in this embodiment, the signal selection unit 112 selects one of the unselected sensing signals as a reference signal when measuring the capacitance to be measured. In another embodiment, the signal selection unit may simultaneously select two sensing signals from the unselected sensing signals as reference signals when measuring the capacitance to be measured.

FIG. 3 is a schematic block diagram of a touch sensing system according to another embodiment of the present invention. Please refer to FIG. 3 , in this embodiment, the signal selection unit 312 simultaneously selects two sensing signals from the unselected sensing signals as a reference for measuring the capacitance to be measured during a third sensing period. Signal. For example, the signal selection unit 312 simultaneously selects the sensing signals Y _n+k and Y _nk as reference signals when measuring the capacitance to be measured during the third sensing period. Taking k=1 as an example, it means that the signal selection unit 312 selects the sensing signals Y _n+1 and Y _n−1 adjacent to the sensing signal Y _n as reference signals when measuring the capacitance to be measured.

It should be noted that during the same sensing period, the signal selection unit 312 is not limited to select symmetrical sensing signals Y _n+k and Y _nk as reference signals when measuring the capacitance to be measured, which may be unselected Any two different sensing signals are selected from the sensing signals as reference signals when measuring the capacitance to be measured.

FIG. 4 is a schematic block diagram of a touch sensing system according to another embodiment of the present invention. Referring to FIG. 4 , in this embodiment, the capacitance sensing device 410 includes a signal selection unit 412 and a plurality of signal sensing units 414 ( 1 )˜414 ( k ). The control unit 430 includes a plurality of analog-digital converters 432 ( 1 )˜ 432 ( k ) and a controller 434 . Wherein, when p is an even number, k=p/2.

In this embodiment, the signal selection unit 412 selects a plurality of signals from different sensing signals Y ₁ -Y _p as the signals to be measured S ₁ -S _k , and selects a plurality of signals from unselected sensing signals As the reference signals R ₁ -R _k , each signal sensing unit receives a signal to be tested and a reference signal to output a difference signal to the corresponding analog-to-digital converter.

FIG. 5 shows that the signal selection unit 412 selects different sensing signals during different sensing periods T ₁ -T _k and transmits them to corresponding signal sensing units as reference signals. Please refer to FIG. 5 . In FIG. 5 , the first column represents the sensing period T ₁ -T _k over time, and the first column represents the signal to be tested or the reference signal corresponding to each column. For example, the second column represents that during the sensing period T ₁ -T _k , the signal selection unit 412 selects the sensing signal Y ₁ as the signal S ₁ to be tested, and transmits it to the signal sensing unit 414 ( 1 ). The third column represents that the signal selection unit 412 respectively selects the sensing signals Y ₂ , Y ₄ , ..., Y _p as the reference signal R ₁ during different sensing periods, and transmits them to the signal sensing unit 414(1) .

As can be seen from FIG. 4 and FIG. 5 , in this embodiment, as far as the signals under test S ₁ -S _k are concerned, the signals under test received by each signal sensing unit are different. For example, during the sensing period T ₁ -T _k , the signal under test S ₁ received by the signal sensing unit 414(1) is the sensing signal Y ₁ , while the signal under test received by the signal sensing unit 414(2) is S ₂ is the sensing signal Y ₃ . In addition, during different sensing periods, the signal to be tested received by the same signal sensing unit is the same. For example, the signal S ₁ to be tested received by the signal sensing unit 414 ( 1 ) during different sensing periods is the sensing signal Y ₁ .

In addition, in this embodiment, as far as the reference signals R ₁ -R _k are concerned, the same signal sensing unit receives different reference signals during different sensing periods. For example, the reference signal R ₁ received by the signal sensing unit 414(1) in different sensing periods is Y ₂ , Y ₄ , ..., Y _p sequentially, while the signal sensing unit 414(2) in different sensing periods The reference signal R ₂ received during the sensing period is Y ₄ , Y ₆ , . . . , Y _p , Y ₂ in sequence.

Therefore, during the sensing period T ₁ -T _k , the signal sensing unit 414(1) compares the difference between the sensing signal Y ₁ and the sensing signals Y ₂ , Y ₄ , . _. . The corresponding difference signals are sequentially output to the analog-to-digital converter 432(1). Similarly, during the sensing period T ₁ -T _k , the signal sensing unit 414(2) compares the sensing signal Y ₃ with the sensing signals Y ₄ , Y ₆ , . . . , Y _p , Y ₂ respectively. difference to sequentially output the corresponding difference signal to the analog-to-digital converter 432(2).

Therefore, the controller 434 performs a digital operation on the received multiple digital signals during each sensing period, so as to obtain the touch position corresponding to the capacitance to be measured on the touch input interface 420 . That is to say, the controller 434 can determine that the touch action occurs at the position of the object sensing unit 420 according to the difference signal.

Accordingly, each signal sensing unit of the touch sensing system 400 of this embodiment receives a signal to be tested and a reference signal, which can effectively offset the noise from the touch input interface 420, thereby improving the difference signal noise-to-signal ratio. Meanwhile, for each signal sensing unit, the signal selection unit 412 selects different sensing signals to be sent to the corresponding signal sensing unit as reference signals during different sensing periods, so as to achieve the purpose of dynamically selecting the reference signal.

It should be noted that the selection method of the signal under test and the reference signal shown in FIG. 5 is an exemplary embodiment of the present invention, and is not intended to limit the present invention. FIG. 6 is another exemplary embodiment of the present invention, which shows different selection modes of the signal selection unit 412 during different sensing periods T ₁ -T _k .

FIG. 7 is a flowchart of steps of a touch sensing method according to an embodiment of the present invention. Please refer to FIG. 1 and FIG. 7 at the same time. The touch sensing method of this embodiment includes the following steps. First, in step S700, at least one signal to be tested is selected from a plurality of sensing signals, for example, at least one signal to be tested Y _n is selected from sensing signals Y ₁ -Y _p . Next, in step S702, at least one reference signal is selected from the unselected sensing signals, for example, at least one reference signal Y _m is selected from the unselected sensing signals. After that, in step S704, a difference signal is generated according to the signal under test Y _n and the reference signal Y _m . Next, in step S706, it is determined according to the difference signal that the touch action occurs at the position of the touch input interface.

In addition, the touch sensing method of the embodiment of the present invention can obtain sufficient teachings, suggestions and implementation descriptions from the descriptions of the embodiments in FIGS.

In addition, in the embodiments of the present invention, although the object sensing device is a touch sensing system as an example, the present invention is not limited thereto. Any object sensing device that can sense and determine the position of an object falls within the scope of protection and coverage of the present invention.

To sum up, in the embodiment of the present invention, the signal selection unit selects at least one reference signal from a plurality of sensing signals as the measurement reference value of the signal to be measured, which can effectively offset the noise from the outside, thereby improving its Noise-to-Signal Ratio. In addition, in different sensing periods, the signal selection unit selects different reference signals to achieve the purpose of dynamically adjusting the measurement reference value.

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims (32)

1. An object sensing device comprising: an object sensing unit for outputting a plurality of sensing signals; a signal selection unit, used to select at least one of the sensing signals as a signal to be tested, and select at least one of the unselected sensing signals as a reference signal; at least one signal sensing unit, configured to output a difference signal according to the signal-to-be-tested and the reference signal; and A control unit is used for judging an object position relative to the object sensing unit according to the difference signal. 2. The object sensing device as claimed in claim 1, wherein the control unit comprises: an analog-to-digital converter for converting the difference signal into a digital signal; and A controller is used for judging the position of the object relative to the object sensing unit according to the digital signal. 3. The object sensing device according to claim 1, wherein the signal selection unit selects at least More than two different sensing signals are used as the reference signal. 4. The object sensing device as claimed in claim 1, wherein there are P sensing signals, and the signal selection unit selects the N sensing signal as the signal to be tested, and selects the (N+K) sensing signal The sensing signal and the (N-K)th sensing signal are used as the reference signal, wherein P, N and K are each a positive integer, 1<N<P, 3≤K+N≤P, 1≤K-N≤(P- 2). 5. The object sensing device according to claim 1, wherein the signal selection unit selects at least two or more of the sensing signals as the signals to be measured, and the unselected sensing signals At least two or more are selected as the reference signals, and each signal sensing unit receives the corresponding signal under test and the corresponding reference signal to output the corresponding difference signal. 6 . The object sensing device as claimed in claim 5 , wherein the signal under test received by each signal sensing unit is different from the other signals under test received by other signal sensing units. 7. The object sensing device as claimed in claim 5, wherein each of the signal sensing units receives the same corresponding signal to be tested during a first sensing period and a second sensing period. 8. The object sensing device as claimed in claim 7, wherein the reference signal received by each signal sensing unit during the first sensing period and the second sensing period is different. 9. The object sensing device as claimed in claim 5, wherein the control unit receives the difference signals and determines the position of the object relative to the object sensing device according to the difference signals. 10. The object sensing device as claimed in claim 9, wherein the control unit comprises: A plurality of analog-to-digital converters, each of which is used to receive the corresponding difference signal and convert it into a corresponding digital signal; and A controller is used for receiving the digital signals and judging the position of the object relative to the object sensing device according to the digital signals. 11. The object sensing device of claim 1, further comprising: A driving unit is used to drive the object sensing unit to output the sensing signals. 12. A touch sensing system comprising: A touch input interface, including a plurality of touch sensors, for outputting a plurality of sensing signals according to a touch action; a signal selection unit, used to select at least one of the sensing signals as a signal to be tested, and select at least one of the unselected sensing signals as a reference signal; at least one signal sensing unit, configured to output a difference signal according to the signal-to-be-tested and the reference signal; and A control unit is used for judging the position where the touch action occurs on the touch input interface according to the difference signal. 13. The touch sensing system as claimed in claim 12, wherein the control unit comprises: an analog-to-digital converter for converting the difference signal into a digital signal; and A controller is used for judging the position where the touch action occurs on the touch input interface according to the digital signal. 14. The touch sensing system according to claim 12, wherein the signal selection unit selects from the unselected sensing signals during a first sensing period and a second sensing period respectively. At least two or more different sensing signals are used as the reference signal. 15. The touch sensing system according to claim 12, wherein there are P sensing signals, the signal selection unit selects the Nth sensing signal as the signal to be tested, and selects the (N+K)th sensing signal The sensing signal and the (N-K)th sensing signal are used as the reference signal, wherein P, N and K are each a positive integer, 1<N<P, 3≤K+N≤P, 1≤K-N≤(P -2). 16. The touch sensing system according to claim 12, wherein the signal selection unit selects at least two or more signals from the sensing signals as the signals to be tested, and the unselected sensing signals At least two or more signals are selected as the reference signals, and each signal sensing unit receives the corresponding signal to be tested and the corresponding reference signal to output the corresponding difference signal. 17. The touch sensing system as claimed in claim 16, wherein the corresponding signal under test received by each signal sensing unit is different from other signals under test corresponding to other signal sensing units. . 18. The touch sensing system according to claim 16, wherein each of the signal sensing units receives the same corresponding signal to be tested during a first sensing period and a second sensing period. 19. The touch sensing system as claimed in claim 18, wherein each of the signal sensing units receives different reference signals during the first sensing period and the second sensing period. 20. The touch sensing system as claimed in claim 16, wherein the control unit receives the difference signals, and judges that the touch action occurs at the position of the touch input interface according to the difference signals. 21. The touch sensing system as claimed in claim 20, wherein the control unit comprises: A plurality of analog-to-digital converters, each of which is used to receive the corresponding difference signal and convert it into a corresponding digital signal; and A controller is used for receiving the digital signals and judging the position where the touch action occurs on the touch input interface according to the digital signals. 22. The touch sensing system of claim 12, further comprising: A driving unit is used to drive the touch sensors to output the sensing signals. 23. A touch sensing method, suitable for a touch sensing system, wherein the touch sensing system includes a touch input interface, the touch sensing method comprising: generating a plurality of sensing signals according to a touch action; selecting at least one of the sensing signals as a signal to be tested; selecting at least one of the unselected sensing signals as a reference signal; generating a difference signal according to the signal under test and the reference signal; and According to the difference signal, it is judged that the touch action occurs at the position of the touch input interface. 24. The touch sensing method according to claim 23, further comprising: converting the difference signal into a digital signal; and According to the digital signal, it is judged that the touch action occurs at the position of the touch input interface. 25. The touch sensing method as claimed in claim 23, wherein in the step of selecting the reference signal, during a first sensing period and a second sensing period, the unselected sensors Among the sensing signals, at least two or more different sensing signals are selected as the reference signal. 26. The touch sensing method according to claim 23, wherein the sensing signals have P sensing signals, and in the step of selecting the signal to be tested, the Nth sensing signal is selected as the signal to be tested , and in the step of selecting the reference signal, select the (N+K)th sensing signal and the (N-K)th sensing signal as the reference signal, wherein P, N and K are each a positive integer, 1< N<P, 3≤K+N≤P, 1≤K-N≤(P-2). 27. The touch sensing method according to claim 23, wherein the touch sensing system further comprises a plurality of signal sensing units, and in the step of selecting the signal to be tested, at least two or more of the Sensing signals are used as the signals to be tested. In the step of selecting the reference signal, at least two or more of the unselected sensing signals are selected as the reference signals, and based on the signal to be tested and the In the step of generating the difference signal from the reference signal, each signal sensing unit receives the corresponding signal under test and the corresponding reference signal to output the corresponding difference signal. 28. The touch sensing method according to claim 27, wherein the corresponding signal under test received by each signal sensing unit is different from other signals under test corresponding to other signal sensing units. . 29. The touch sensing method according to claim 27, wherein each of the signal sensing units receives the same corresponding signal to be tested during a first sensing period and a second sensing period. 30. The touch sensing method as claimed in claim 29, wherein the reference signals received by each of the signal sensing units during the first sensing period and the second sensing period are different. 31. The touch sensing method as claimed in claim 27, wherein in the step of determining that the touch action occurs at the position of the touch input interface, it is determined that the touch action occurs at the touch input interface according to the difference signals The location of the control input interface. 32. The touch sensing method according to claim 23, further comprising: A driving signal is generated to drive the touch sensors to output the sensing signals after receiving the driving signal.

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