CN109668659B - Pressure sensor and pressure sensing method - Google Patents

Abstract

The present invention discloses a pressure sensor, comprising a first electrode plate; a plurality of second electrodes plates; an elastic body arranged between the first electrode plate and the plurality of second electrodes plates; a first switch, comprising a first end coupled to the first electrode plate, and a second end selectively coupled to a first electrode plate receiving end or a grounding end; and a plurality of second switches, wherein each second switch comprises a first end coupled to one of the plurality of second electrodes plates, and a second end selectively coupled to a second electrode plate receiving end, the grounding end or a driving signal end.

Description

Pressure sensor and pressure sensing method

technical field

The present invention relates to a pressure sensor and a pressure sensing method, in particular to a pressure sensor and a pressure sensing method that can be adjusted according to a lower pressure channel and a capacitance value.

Background technique

With the advancement of technology, touch-sensitive electronic devices have been widely used by the general public. In addition to judging the operation point touched by the user, the current touch electronic device can also provide the function of judging the multi-segment pressing force, so as to further expand the touch function of the mobile device and improve the user's experience.

The existing touch device uses a capacitive pressure sensing method to determine the pressure channel. For example, an elastic body is arranged between the two pole plates, and the pressing force channel is determined by the capacitance value sensed by the pole plates. When a force is pressed on the plate, the distance between the two plates will change and the capacitance value sensed by the plates will also change. However, a common problem is that the change of the capacitance value and the pressing force channel tend to exhibit a non-linear relationship, resulting in inconsistent sensing sensitivity. Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a capacitance value and a downward pressure channel obtained during conventional capacitive pressure sensing. Since the elastomer has a certain volume, the thickness of the elastomer is inversely proportional to the cross-sectional area, and the capacitance value is proportional to the cross-sectional area of the elastomer and inversely proportional to the thickness of the elastomer. As shown in Figure 1, in the low pressure region (LP), when the lower pressure channel increases sharply, the capacitance value changes slightly. In the high pressure range (HP), when the lower pressure channel increases slightly, the capacitance value increases sharply. Therefore, since the capacitance value obtained by the conventional touch device has a nonlinear relationship with the downward pressure channel, the sensitivity corresponding to the downward pressure channel cannot be fixed when the user presses, thereby reducing the user's product satisfaction when using the touch device. Spend. Therefore, how to provide corresponding linear signal feedback according to the downforce channel to further improve the user's satisfaction when using the product has become one of the goals of the industry.

SUMMARY OF THE INVENTION

Therefore, in order to solve the above problems, the present invention provides a pressure sensor and a pressure sensing method that can provide corresponding linear signal feedback according to the downward pressure channel to further improve the user's satisfaction when using the product.

The invention provides a pressure sensor, comprising a first pole plate; a plurality of second pole plates; an elastic body disposed between the first pole plate and the plurality of second pole plates; a first switch , comprising a first end coupled to the first plate, and a second end selectively coupled to a first plate receiving end or a ground end; and a plurality of second switches, wherein Each second switch includes a first end coupled to one of the plurality of second plates, and a second end selectively coupled to a second plate receiving end, the The ground terminal or a driving signal terminal.

The present invention also provides a pressure sensing method, which is suitable for a pressure sensor. The pressure sensor includes an elastic body, a first electrode plate and a plurality of second electrode plates, and the elastic system is disposed on the first electrode. Between the plate and the plurality of second plates, the pressure sensing method includes setting an electrode connection configuration, and the electrode connection configuration includes at least a part of the plurality of second plates being coupled A driving signal terminal and the remaining second plates are coupled to a ground terminal; and different forces are applied to the first plates, and the first plates corresponding to the different forces are detected according to the electrode connection configuration Capacitance value and detecting compressed electrode area; and storing the electrode connection configuration, the corresponding relationship between the first capacitance value corresponding to different forces and the compressed electrode area.

Description of drawings

FIG. 1 is a schematic diagram of a capacitance value and a downward pressure channel obtained during traditional capacitive pressure sensing.

FIG. 2 is a schematic diagram of a pressure sensor according to an embodiment of the present invention.

FIG. 3 is a partial perspective view of the pressure sensor of FIG. 2 .

4 to 6 are schematic diagrams of a pressure sensing process according to an embodiment of the present invention, respectively.

7 is a schematic diagram of characteristic curves obtained under different electrode connection configurations according to an embodiment of the present invention.

8 to 11 are schematic diagrams illustrating the second electrode plate according to the embodiment of the present invention.

Among them, the reference numerals are described as follows:

20 Pressure sensor

200 first plate

202 Elastomer

204_1～204_5, 804_1～804_8,

904_1～904_7, 1004_1～1004_6 Second plate

, 1104_1～1104_16

206 First switch

208_1～208_5 Second switch

210 Control Unit

212 drive unit

214 processing units

216 storage units

Gnd ground terminal

HP, LP interval

L1, L2 curve

Ra～Re receiving end of the second plate

Rx first plate receiver

Tx drive signal terminal

40, 50, 60 process

400～408, 500～508, 600～614 steps

Detailed ways

Please refer to FIG. 2 and FIG. 3 . FIG. 2 is a schematic diagram of a pressure sensor 20 according to an embodiment of the present invention. FIG. 3 is a partial perspective view of the pressure sensor 20 in FIG. 2 . The pressure sensor 20 can be applied to various touch electronic devices, such as tablet computers, smart phones, smart bracelets, smart watches, and the like. The pressure sensor 20 includes a first electrode plate 200 , an elastic body 202 and second electrode plates 204_1 to 204_5 . The elastic body 202 may be an elastic three-dimensional material, disposed between the first pole plate 200 and the second pole plate 202, and can generate elastic deformation (Elastic Deformation) according to an external force. When an external force is applied to the first pole plate 200, the elastic body 202 can elastically deform according to the magnitude of the external force. In this case, the cross-sectional area of the elastic body 202 will change, and the first pole plate 200 and the second pole plate 204 The distance between them will also change to produce the corresponding capacitance value.

Besides, the pressure sensor 20 further includes a first switch 206 , second switches 208_1 to 208_5 , a control unit 210 , a driving unit 212 , a processing unit 214 and a storage unit 216 . The first switch 206 includes a first terminal and a second terminal, wherein the first terminal of the first switch 206 is coupled to the first electrode plate 200 , and the second terminal of the first switch 206 is selectively coupled to the first electrode Board receiving terminal Rx or ground terminal Gnd. For example, when the second end of the first switch 206 is coupled to the first plate receiving end Rx, the processing unit 214 can receive the sensing signal via the first plate receiving end Rx to determine the difference between the first plate 200 and the second plate A first capacitance value between the plates 204_1 ˜ 20_5 . At this time, the first capacitance value may be related to a total capacitance value between the plates. Each second switch corresponds to a corresponding second electrode plate, each second switch includes a first end and a second end, wherein the first end of each second switch is coupled to the corresponding second electrode plate, and the second terminal of each second switch is selectively coupled to a corresponding second plate receiving terminal, the ground terminal Gnd or the driving signal terminal Tx. For example, as shown in FIG. 2, the first end of the second switch 208_1 is coupled to the second plate 204_1, and the second end of the second switch 208_1 can be selectively coupled to the second plate receiving end Ra, grounded The terminal Gnd or the driving signal terminal Tx. The first end of the second switch 208_2 is coupled to the second plate 204_2, and the second end of the second switch 208_2 can be selectively coupled to the second plate receiving end Rb, the ground end Gnd or the driving signal end Tx ,So on and so forth. In one embodiment, when the second end of the first switch 206 is coupled to the ground terminal Gnd and the second end of the second switch 208_1 is coupled to the second plate receiving end Ra, the processing unit 214 can pass through the second plate The receiving end Ra receives the sensing signal to determine a second capacitance value between the first electrode plate 200 and the second electrode plate 204_1. At this time, the second capacitance value may be related to an individual capacitance value between the second electrode plate 204_1 and the first electrode plate 200 , and so on.

The control unit 210 is used for generating a control signal to control the operations of the first switch and the second switches 208_1 ˜ 208_5 . For example, according to the control signal generated by the control unit 210, the second terminal of the first switch 206 can be connected to the first plate receiving terminal Rx or the ground terminal Gnd, so as to couple the first plate 200 to the first pole Board receiving terminal Rx or ground terminal Gnd. For example, according to the control signal generated by the control unit 210, the second terminals of the second switches 204_1-204_5 can be coupled to the corresponding second plate receiving terminals Ra-Re, the ground terminal Gnd or the driving signal terminal Tx. The driving unit 212 is coupled to the driving signal terminal Tx for generating a driving signal, and the driving signal generated by the driving unit 212 can be transmitted to the second electrode plate coupled to the driving signal terminal Tx. The processing unit 214 is coupled to the first plate receiving end Rx and the second plate receiving ends Ra-Re, and is used to receive the first sensing signal S through the first plate receiving end Rx during normal operation and determine accordingly The first capacitance value C corresponding to the first force and the corresponding sensing signals are received through the first plate receiving end Rx and the second plate receiving ends Ra-Re during the test, so as to determine the first capacitance corresponding to different forces Values correspond to the area of the compressed electrode.

Further, the control unit 210 can generate corresponding control signals according to the selected electrode connection configuration to control the operations of the first switch and the second switch. For example, the electrode connection configuration may include that at least a part of the second electrode plates 204_1 to 204_5 are coupled to the ground terminal Gnd or are in a floating state and the rest of the second electrode plates are coupled to the driving signal terminal Tx. For example, it is assumed that a first electrode connection configuration includes the second electrode plates 204_1 , 204_2 and 204_5 coupled to the driving signal terminal Tx and the second electrode plates 204_3 and 204_4 coupled to the ground terminal Gnd. In this way, the control unit 210 can generate corresponding control signals according to the first electrode connection configuration. As shown in FIG. 2 and FIG. 3 , according to the control signal, one end of the second switch 208_1 is connected to the second plate 204_1 , and the other end of the second switch 208_1 is connected to the driving signal terminal Tx, so as to couple the second plate 204_1 Connected to the drive signal terminal Tx. One end of the second switch 208_2 is connected to the second electrode plate 204_2, and the other end of the second switch 208_2 is connected to the driving signal terminal Tx, so as to couple the second electrode plate 204_2 to the driving signal terminal Tx. One end of the second switch 208_5 is connected to the second electrode plate 204_5, and the other end of the second switch 208_5 is connected to the driving signal terminal Tx, so as to couple the second electrode plate 204_5 to the driving signal terminal Tx. According to the control signal, one ends of the second switches 208_3 and 208_4 are connected to the second pole plates 204_3 and 204_4 respectively, and the other ends of the second switches 208_3 and 208_4 are respectively coupled to the ground terminal Gnd. In this way, the driving signals generated by the driving unit 212 are transmitted to the second electrode plates 204_1 , 204_2 and 204_5 . At this time, the second electrode plates 204_3 and 204_4 are coupled to the ground terminal Gnd and receive no driving signal. Further, according to the control signal, one end of the first switch 206 is connected to the first plate 200, and the other end of the first switch 206 is connected to the first plate receiving end Rx, so as to couple the first plate 200 to a Plate receiving end Rx. In this case, the processing unit 214 can receive the corresponding sensing signal via the first plate receiving terminal Rx and determine the corresponding first capacitance value accordingly, and determine the strength of the external force according to the first capacitance value.

To put it simply, the pressure sensor 20 changes the distance between the first pole plate and the second pole plate through the elastic deformation of the elastic body 202, and then senses the corresponding capacitance value to determine the amount of downward pressure of the user, When the elastic body 202 is elastically deformed under pressure, the cross-sectional area and thickness of the elastic body 202 will change, which further changes the medium between part of the second electrode plate and the first electrode plate 200 (ie, the capacitance of part of the area). The medium is converted from air to an elastic body 202), thereby changing the capacitance value between the first electrode plate 200 and all the second electrode plates. Meanwhile, the pressure sensor 20 can generate corresponding control signals according to the selected electrode connection configuration to control the operations of the first switch and the second switch. For example, as shown in FIG. 3, the cross-sectional area of the elastic body 202 covers the second electrode plates 204_1-204_5, and according to a first electrode connection configuration, the second electrode plates 204_1, 204_2 and 204_5 are coupled to the driving signal The terminal Tx and the second plates 204_3 and 204_4 are coupled to the ground terminal Gnd. Therefore, the pressure sensor can obtain a capacitance value corresponding to the amount of downward pressure by measuring on the first electrode plate 200 . In other words, a part of the second electrode plates can be coupled to the ground terminal or switched to a floating state according to requirements, and the rest of the second electrode plates can be coupled to the driving unit 212 to receive driving signals, so as to improve nonlinear sensing and the problem of unstable sensitivity.

During a normal operation, the operation of the pressure sensor 20 can be summarized as a process 40. Please refer to FIG. 4. FIG. 4 is a schematic diagram of a pressure sensing process 40 according to an embodiment of the present invention. The process 40 includes the following steps:

Step 400: Start.

Step 402: Generate a control signal according to the electrode connection configuration.

Step 404: According to the control signal, at least one second electrode plate is coupled to the ground terminal and the remaining second electrode plates are coupled to the driving signal terminal.

Step 406: Receive the sensing signal through the first plate receiving end and determine the corresponding capacitance value accordingly.

Step 408: End.

According to the process 40, in step 402, the control unit 210 can generate corresponding control signals according to the selected electrode connection configuration to control the first switch 206 and the second switches 208_1-208_5. The selected electrode connection configuration may be a preset electrode connection configuration or an electrode connection configuration selected by a user. For example, assume that the selected electrode connection configuration is a first electrode connection configuration. The first electrode connection configuration includes that the second electrode plates 204_1, 204_2 and 204_5 are coupled to the driving signal terminal Tx and the second electrode plates 204_3 and 204_4 are coupled to the ground terminal Gnd. The user can notify the control unit 210 that the selected electrode connection configuration is the first electrode connection configuration through hardware or software.

In step 404, at least a part of the second electrode plates 204_1-204_5 are coupled to the ground terminal or switched to a floating state according to the control signal, and the remaining second electrode plates are coupled to the driving signal terminal Tx. For example, if the selected electrode connection configuration is the first electrode connection configuration, according to the control signal generated by the control unit 210, through the connection operation of the second switches 208_1, 208_2 and 208_5, the second electrode plate 204_1, 204_2 and 204_5 can be respectively coupled to the driving signal terminal Tx. According to the control signal generated by the control unit 210, through the connection operation of the second switches 208_3 and 208_4, the second plates 204_3 and 204_4 can be respectively coupled to the ground terminal Gnd.

In step 406, when the user applies force to the first electrode plate 200, the processing unit 214 receives a sensing signal through the first electrode plate receiving end Rx and determines the corresponding capacitance value accordingly. In this way, the processing unit 214 can determine the force currently applied by the user according to the determined capacitance value.

On the other hand, in order to provide users with more electrode connection configuration options and optimization adjustments. During a test operation, the operation of the pressure sensor 50 can be summarized into a process 50. Please refer to FIG. 5, which is a schematic diagram of a pressure sensing process 50 according to an embodiment of the present invention. The process 50 includes the following steps:

Step 500: Start.

Step 502: Set the electrode connection configuration.

Step 504 : Apply different force to the first electrode plate, and detect the first capacitance value and the compressed electrode area corresponding to the different force according to the electrode connection configuration.

Step 506 : Store the electrode connection configuration, the corresponding relationship between the first capacitance values corresponding to different forces and the area of the compressed electrode.

Step 508: End.

The pressure sensor 20 can set a variety of different electrode connection configurations according to the process 50, and adjust the coupling state of the second switch 204 through the electrode connection configuration, so as to obtain the first capacitance value corresponding to different forces and compress the electrode area . Since the area of the compressed electrode is related to the amount of downforce, the area of the compressed electrode can be used as a relevant parameter of the amount of downforce. Through the process 50, the corresponding relationship between the first capacitance value corresponding to different forces and the area of the compressed electrode can be obtained, that is, the characteristic relationship between the downward force and the capacitance value between the first electrode plate 200 and the second electrode plates 204_1-204_5 . It varies with different electrode connection configurations. The pressure sensor 20 can measure the relationship curve between the downward force and the capacitance value corresponding to each electrode connection configuration, and then select the electrode connection configuration that best meets the needs of the user to provide Perform pressure detection operations on users.

According to the process 50, in step 502, the processing unit 214 first sets an electrode connection configuration, sets at least a part of the second electrode plates 204_1 to 204_5 to be grounded or switched to a floating state, and the rest of the second electrode plates are coupled to The driving signal terminal Tx is used to receive the driving signal.

In step 504 , the processing unit 214 may instruct the control unit 210 according to the set electrode connection configuration to perform the switching of the first switch 206 and the second switches 208_1 to 208_5 to obtain the corresponding correspondence under various downforce amounts The capacitance value of , and the corresponding compressed electrode area (cross-sectional area of the elastic body 102 ) under various down force amounts, so as to obtain a relationship diagram between down force amounts and capacitance values.

In one embodiment, in step 504, regarding the method of obtaining the corresponding capacitance values and corresponding compressed electrode areas under various down force amounts, the processing unit 214 first transmits an electrode connection configuration to the control unit 214. In the unit 210, the control unit 210 can generate a corresponding control signal according to the electrode connection configuration, and couple a corresponding part of the second electrode plates 204_1-204_5 to the ground terminal Gnd through the connection operation of the second switches 208_1-208_5, and The remaining second electrode plates are coupled to the driving signal terminal Tx, and the first electrode plate 200 is coupled to the first electrode plate receiving end Rx through the first switch. Therefore, when a specific downward force is applied to the first plate 200 of the pressure sensor 20, the processing unit 214 coupled to the first plate receiving end Rx can receive the first sensing signal S at the first plate receiving Rx A first capacitance value C is determined accordingly. At this time, the first capacitance value determined by the processing unit 214 is the first capacitance value corresponding to the specific downward force amount. It is worth noting that since at least a part of the second electrode plate 206 is coupled to the ground terminal Gnd, the first sensing capacitance value measured by the processing unit 214 here is under the condition of applying the specific down force amount , the capacitance value adjusted by the electrode connection configuration.

In addition, after the processing unit 214 determines the first capacitance value corresponding to the specific down force amount, the processing unit 214 instructs the control unit 210 to generate a corresponding control signal to couple the first electrode plate 200 to the ground terminal Gnd, and The second electrode plates 204_1 to 204_5 are respectively coupled to the corresponding second electrode plate receiving terminals. For example, the second terminal of the first switch 206 is switched from the first plate receiving terminal Rx to the ground terminal Gnd. The second terminal of the second switch 208_1 is switched from the ground terminal Gnd, the driving signal terminal Tx or the floating state to the second plate receiving terminal Ra. The second terminal of the second switch 208_2 is switched to the second plate receiving terminal Rb. Similarly, the second terminals of the second switches 208_3 - 208_5 are also switched to the second plate receiving terminals Rc - Re, respectively. In this way, the second electrode plates 204_1 - 204_5 are respectively coupled to the second electrode plate receiving ends Ra - Re. In this case, the processing unit 214 may receive the second sensing signals S_1 ˜ S_5 corresponding to the second electrode plates 204_1 ˜ 204_5 through the second electrode plates 204_1 ˜ 204_5 respectively, and determine the corresponding second electrode plates 204_1 accordingly. ~204_5 second capacitance values C_1~C_5. Next, the processing unit 214 determines the compressed second electrode plate from the second electrode plates 204_1 to 204_5 according to the second capacitance values C_1 to C_5 and calculates the area of the area covered by the compressed second electrode plate, as the compressed electrode area corresponding to the specific force.

Further, since the permittivity of air is smaller than that of the elastic body 202 , the second electrode plate that is not in contact with the elastic body 202 will measure a higher value than the second electrode plate that is in contact with the elastic body 202 . Therefore, the processing unit 214 can determine a compressed electrode area (equivalent to the cross-sectional area of the elastic body 202 ) accordingly. Specifically, for each second plate, the processing unit 214 compares the second capacitance value measured by each second plate with a predetermined capacitance value, and when the second capacitance value is greater than the predetermined capacitance When the value is , it is determined that the corresponding second electrode plate is a compressed second electrode plate (or the corresponding second electrode plate is in contact with the elastic body 202 ). If the second capacitance value is smaller than the preset capacitance value, it is determined that the corresponding second electrode plate is an uncompressed second electrode plate (or the corresponding second electrode plate is not in contact with the elastic body 202 ). The processing unit 214 sums up the areas covered by all the second electrode plates 204 judged to be compressed (or in contact with the elastic body 202 ), as the area of the compressed electrode corresponding to the specific force. That is, the processing unit 214 calculates the area of the area covered by the second electrode plate determined to be compressed as the area of the compressed electrode corresponding to the specific force. For example, taking FIG. 3 as an example, if the second capacitance values C_1 - C_5 corresponding to the second electrode plates 204_1 - 204_5 are all greater than the predetermined capacitance value, it is determined that the second electrode plates 204_1 - 204_5 are all compressed The diode plates (or it is determined that all the second plates 204_1 to 204_5 are in contact with the elastic body 202 ). The processing unit 214 calculates all the areas of the regions surrounded by the second electrode plates 204_1 to 204_5 as the compressed electrode area corresponding to the specific force. Alternatively, if the second capacitance value C_1 corresponding to the second electrode plate 204_1 is smaller than the preset capacitance value, the second electrode plate 204_1 is judged to be an uncompressed second electrode plate (or one that is not in contact with the elastic body 202 ). second plate). When the second capacitance values C_2-C_5 corresponding to the second electrode plates 204_2-204_5 are all greater than the preset capacitance value, it is determined that the second electrode plates 204_2-204_5 are all compressed second electrode plates (or the second electrode plate 204_2 is determined to be compressed). ~204_5 are all in contact with the elastomer 202). The processing unit 214 calculates all areas of the regions surrounded by the second electrode plates 204_2 to 204_5 as the compressed electrode area corresponding to the specific force.

Likewise, and so on, when different forces are applied to the first electrode plate 200, the processing unit 214 can determine the first capacitance values corresponding to the different down force amounts and obtain the compressed electrode areas corresponding to the different forces. After obtaining the first capacitance values corresponding to different pressing force amounts and the compressing electrode areas corresponding to different forces, the first capacitance values and compressing electrode areas corresponding to different forces under the set electrode connection combination configuration can be determined relationship curve characteristics.

In step 506 , the processing unit 214 stores the electrode connection configuration set in step 202 , the corresponding relationship between the first capacitance values corresponding to different forces and the compressed electrode area in the storage unit 216 . When the user selects the electrode connection configuration, the most suitable electrode connection configuration can be selected according to the electrode connection configuration stored in the storage unit 216, the corresponding relationship between the first capacitance value and the compressed electrode area. For example, as shown in FIG. 7 , FIG. 7 is a schematic diagram of characteristic curves obtained under different electrode connection configurations according to an embodiment of the present invention. Under a first electrode connection configuration, the corresponding relationship between the first capacitance value obtained by the pressure sensor 20 and corresponding to different amounts of down pressure and the area of the compressed electrode can be represented by the characteristic curve L1 . In a second electrode connection configuration, the corresponding relationship between the first capacitance value obtained by the pressure sensor 20 and corresponding to different down pressure amounts and the area of the compressed electrode can be represented by the characteristic curve L2. In this case, the user can select the electrode connection configuration according to the electrode connection configuration stored in the storage unit 216 and the corresponding relationship between the first capacitance value and the compressed electrode area (ie, the characteristic curves L1 and L2).

To put it simply, the pressure sensor 20 can obtain the capacitance value of the first electrode plate 200 corresponding to different forces and the area of the detected compressed electrode according to the process 50, and obtain the relationship curve between the downward force and the capacitance value corresponding to the different electrode connection configurations. , in which the user can choose the electrode connection configuration that meets the requirements, or the system can determine the electrode connection configuration that best meets the user's needs according to the relationship between the downward force and the capacitance value. The selected electrode connection configuration operates the pressure sensing function.

Furthermore, the pressure sensor 20 can not only obtain a better electrode connection configuration according to various electrode connection configurations according to the process 50, but also judge whether it meets the target linear curve according to the obtained capacitance value, and adjust the first electrode connection configuration in real time. The coupling configuration of the diode plates 204 to obtain the desired linear curve. The operation of the real-time adjustment of the pressure sensor 20 can be summarized as a process 60 , please refer to FIG. 6 , which is a pressure sensing process 60 according to an embodiment of the present invention. The process 60 includes the following steps:

Step 600: Start.

Step 602: Apply a specific force on the pressure sensor.

Step 604: Detect the capacitance value of the first electrode plate corresponding to the specific force and detect the area of the compressed electrode.

Step 606 : Compare the obtained capacitance value with the default curve to see if the difference between the capacitance values is within the preset difference value; if so, go to Step 610 , if not, go to Step 608 .

Step 608 : Adjust the electrode coupling configuration of the second electrode plate.

Step 610 : the processing unit determines whether the applied specific weight is less than the maximum weight; if so, go to step 612 , if not, go to step 614 .

Step 612: Increase the unit weight to the specified weight.

Step 614: End.

Therefore, the pressure sensor 20 can sense the capacitance value and detect the compressed electrode area in real time according to the process 60 , compare it with the default curve, and adjust the relationship curve between the downward force and the capacitance value according to the comparison result.

Specifically, when a specific pressure is applied to the pressure sensor 20 (ie, step 602 ), the processing unit 214 will sense the first capacitance value and compress the electrode area (ie, step 604 ). It is worth noting that the processing unit 214 stores a default curve, which is the relationship curve between the downward force and the capacitance value used to determine the linearity. After the processing unit 214 obtains the first capacitance value and compresses the electrode area, it will further Comparing with the default curve, it is determined whether the difference from the default curve is within the preset difference, so as to conform to the linear downforce and capacitance value characteristics (ie, step 606 ). When the comparison result is that the capacitance value is too large, the processing unit 214 adjusts the electrode coupling configuration, instructing to couple part of the second electrode plate to the ground terminal Gnd, so as to reduce the gap between the first electrode plate 200 and the second electrode plate 204 Sensed capacitance value. On the contrary, when the capacitance value is too small, the processing unit 214 adjusts the electrode coupling configuration, instructing to cancel the state of the second electrode plate 204 partially coupled to the ground terminal Gnd, so as to maintain the linear relationship between the downward force and the capacitance value ( That is, step 608). After the processing unit 214 determines that the obtained capacitance value conforms to the linear relationship of the default curve, the processing unit 214 further determines whether the applied specific pressure is less than the maximum pressure (ie, step 610 ). If the applied specific weight is less than the maximum weight, a unit of pressure is increased to the specific weight, so as to continue sensing the amount of downforce and the capacitance value (ie, step 612 ). If not, if the applied specific weight is greater than or equal to the maximum weight, the process ends (ie, step 614).

It is worth noting that, compared with the process 50 in the process 60, the pressure sensor 20 can sense the pressure and capacitance value in real time according to the process 60, and then compare with the stored default curve to obtain the electrode coupling configuration that meets the requirements . According to the process 60 , the pressure sensor 20 does not need to obtain the relationship curve between the downward force and the capacitance value for different electrode connection configurations, and takes the default curve as the linearity, and can make real-time judgment to obtain the electrode coupling set that meets the linearity requirements. state to provide operation of the pressure sensing function during normal operation.

It should be noted that the foregoing embodiments are only used to illustrate the concept of the present invention, and those skilled in the art can make various modifications accordingly, but are not limited thereto. For example, the control unit 210 couples a part of the second electrode plate 204 to the ground terminal Gnd according to the electrode coupling configuration to adjust the capacitance value sensed on the first electrode plate 200 , and is not limited to connecting part of the second electrode plate 204 to the ground terminal Gnd. The plate 204 is coupled to the ground terminal Gnd, and part of the second plate 204 can also be switched to a floating state according to system requirements, as long as the capacitance value sensed on the first plate 200 can be changed. In addition, the arrangement of the second electrode plates 204 is not limited to a single-row, mutually parallel arrangement, and the shape or size is not limited to a rectangle or the same size. Preferably, the arrangement, shape or size of the second electrode plates 204 can be adjusted according to system requirements to achieve better linearity.

Please refer to FIG. 8 to FIG. 11 . FIGS. 8 to 11 are schematic diagrams illustrating the second electrode plate according to the embodiment of the present invention. As shown in FIG. 8 , the distances between each of the second electrode plates are the same and are arranged in a rectangular shape parallel to each other. The second electrode plate may have different widths. As shown in FIG. 8 , the second electrode plate at the center position has a wider width, and its width gradually decreases as the distance from the center position increases. The distances between the two second pole plates may be different from each other. As shown in Figure 9, the rectangles of the same shape of each second pole plate are arranged in parallel to each other, however, the spacing distance between the second pole plates is different from each other, and the spacing distance gradually increases with the distance from the center position. Decrease. As shown in FIG. 10 , two groups of parallelogram-shaped metals of the second plate have the same shape and are arranged parallel to each other, and the two groups of rectangular metals are symmetrical to each other according to the center position. As shown in Figure 11, the second pole plate is a double-row rectangular metal, the upper row of rectangular metal is located in the second pole plate closer to the center, and its width is wider, and the width decreases with the distance from the center position; The width of the second electrode plate with the rectangular metal located closer to the center position is narrower, and the width increases with the distance from the center position.

To sum up, when the traditional pressure sensor performs pressure sensing, due to structural factors, the applied pressure cannot exhibit a linear relationship with the measured capacitance value, which seriously affects the user's experience of touch. In contrast, the pressure sensor of the present invention provides more linear sensing by adjusting the input of the driving signal of the second electrode plate, so as to improve the user's experience. In addition, the pressure sensor of the present invention uses the elastic body to sense the pressure, the first electrode plate and the second electrode plate to measure the capacitance, and the processing unit further determines the coupling relationship of the second electrode plate to obtain a better downward force amount. Curve characteristic with capacitance value. Therefore, the user can obtain a satisfactory linear signal feedback according to the downward pressure channel during use, which further improves the user's satisfaction when using the product.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A pressure sensor, comprising:

a first electrode plate;

a plurality of second electrode plates;

the elastic body is arranged between the first polar plate and the plurality of second polar plates;

a first switch, including a first end coupled to the first electrode plate, and a second end selectively coupled to a receiving end of the first electrode plate or a grounding end;

a plurality of second switches, wherein each second switch comprises a first end coupled to one of the second electrode plates and a second end selectively coupled to a second electrode plate receiving end, the ground end or a driving signal end; and

a control unit for generating a control signal to control the first switch and the plurality of second switches;

wherein, during a normal operation, the control unit generates the control signal according to an electrode connection configuration, the electrode connection configuration includes at least a portion of the plurality of second plates coupled to the ground terminal or in a floating state and the remaining second plates coupled to the driving signal terminal,

during the normal operation, according to the control signal, the first terminal of the first switch is coupled to the first plate and the second terminal of the first switch is coupled to the first plate receiving terminal, and according to the control signal and the electrode connection configuration, at least a portion of the second terminals of the plurality of second switches are coupled to the ground terminal or in the floating state and the second terminals of the remaining second switches are coupled to the driving signal terminal, so as to connect the corresponding second plates to the driving signal terminal.

2. The pressure sensor of claim 1, further comprising

A driving unit coupled to the driving signal terminal for generating a driving signal; and

the processing unit is coupled to the first electrode plate receiving end and used for receiving a first sensing signal through the first electrode plate receiving end during the normal operation period and judging a first capacitance value corresponding to a first force according to the first sensing signal.

3. The pressure sensor of claim 2, wherein the processing unit is configured to set the electrode connection configuration during a test period, and the processing unit detects first plate capacitance values and detects compressive electrode areas corresponding to different forces based on the electrode connection configuration when the different forces are applied to the first plate.

4. The pressure sensor of claim 3, further comprising

And the storage unit is used for storing the electrode connection configuration, the first capacitance values corresponding to different forces and the corresponding relation of the area of the compression electrode.

5. The pressure sensor of claim 3, wherein upon application of the first force to the first plate, the control unit generates the control signal according to the electrode connection configuration such that the first end of the first switch is coupled to the first electrode plate and the second end of the first switch is coupled to the first electrode plate receiving end, second terminals of the at least a portion of the plurality of second switches are coupled to the ground terminal or switched to the floating state and second terminals of the remaining second switches are coupled to the driving signal terminal, the driving unit inputs the driving signal to the connected second polar plate through the driving signal end, the processing unit receives the first sensing signal through the first electrode plate receiving end and judges a first capacitance value corresponding to the first force according to the first sensing signal.

6. The pressure sensor of claim 3, wherein the control unit generates the control signal when the first force is applied to the first plate such that the first terminal of the first switch is coupled to the first plate and the second terminal of the first switch is coupled to the ground terminal to switch the first plate to the ground terminal, and each second switch is coupled to a corresponding second plate receiving terminal to couple each second plate to the corresponding second plate receiving terminal, and the processing unit receives a plurality of second sensing signals through the corresponding second plate receiving terminals to detect a plurality of second capacitance values corresponding to the plurality of second plates and determine a compressed second plate from among the plurality of second plates, and the processing unit calculates the area of the area covered by the second polar plate which is judged to be compressed to be the area of the compressed electrode corresponding to the first force.

7. The pressure sensor as claimed in claim 6, wherein for each second plate, the processing unit receives a second sensing signal through the corresponding second plate receiving end of each second plate and determines a second capacitance value corresponding to each second plate, the processing unit determines each second plate to be a compressed second plate when the second capacitance value corresponding to each second plate is greater than or equal to a predetermined capacitance value, and determines each second plate to be an uncompressed second plate when the second capacitance value corresponding to each second plate is less than the predetermined capacitance value.

8. A pressure sensing method is suitable for a pressure sensor, the pressure sensor comprises an elastic body, a first polar plate and a plurality of second polar plates, the elastic body is arranged between the first polar plate and the plurality of second polar plates, the pressure sensing method comprises the following steps:

setting an electrode connection configuration, wherein the electrode connection configuration comprises at least one part of the plurality of second plates coupled to a grounding end or switched to a floating state and the rest of the second plates coupled to a driving signal end;

applying different forces to the first plate and detecting first capacitance values and compressive electrode areas corresponding to the different forces according to the electrode connection configuration, wherein the applying different forces to the first plate and detecting first capacitance values and compressive electrode areas corresponding to the different forces according to the electrode connection configuration comprises:

coupling the first plate to a first plate receiving terminal and coupling the at least a portion of the plurality of second plates to the ground or to the floating state and coupling the remaining second plates to the driving signal terminal according to the electrode connection configuration while applying a first force to the first plate; and

inputting a driving signal to the at least one portion of the plurality of second electrode plates through the driving signal terminal, and receiving a first sensing signal through the first electrode plate receiving terminal to determine a first capacitance corresponding to the first force; and

storing the electrode connection configuration, the first capacitance corresponding to different forces and the corresponding relation of the area of the compressed electrode.

9. A pressure sensing method is suitable for a pressure sensor, the pressure sensor comprises an elastic body, a first polar plate and a plurality of second polar plates, the elastic body is arranged between the first polar plate and the plurality of second polar plates, the pressure sensing method comprises the following steps:

setting an electrode connection configuration, wherein the electrode connection configuration comprises at least one part of the plurality of second plates coupled to a grounding end or switched to a floating state and the rest of the second plates coupled to a driving signal end;

applying different forces to the first plate and detecting first capacitance values and compressive electrode areas corresponding to the different forces according to the electrode connection configuration, wherein the applying different forces to the first plate and detecting first capacitance values and compressive electrode areas corresponding to the different forces according to the electrode connection configuration comprises:

when a first force is applied to the first polar plate, the first polar plate is switched to a grounding end, and the plurality of second polar plates are respectively coupled to corresponding second polar plate receiving ends; and

detecting a plurality of second capacitance values corresponding to the plurality of second polar plates and determining a compressed second polar plate from the plurality of second polar plates; and

calculating the area of the area covered by the second polar plate which is judged to be compressed to be used as the area of the compressed electrode corresponding to the first force; and

storing the electrode connection configuration, the first capacitance corresponding to different forces and the corresponding relation of the area of the compressed electrode.

10. The pressure sensing method of claim 9, wherein detecting a plurality of second capacitance values corresponding to the plurality of second plates and determining a compressed second plate from among the plurality of second plates comprises:

for each second polar plate, receiving a second sensing signal through a corresponding second polar plate receiving end of each second polar plate to judge a second capacitance value corresponding to each second polar plate;

when the second capacitance value corresponding to each second polar plate is greater than or equal to a preset capacitance value, judging that each second polar plate is a compressed second polar plate; and

and when the second capacitance value corresponding to each second polar plate is smaller than the preset capacitance value, judging that each second polar plate is an uncompressed second polar plate.

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