TWI435258B - Inductive touch sensor and its detection method - Google Patents

Description

Inductive touch sensor and detection method thereof

The invention relates to a touch sensor, in particular to a touch sensor using an inductor technology and a detecting method thereof.

In the past 20 years, touch technology has been widely used, such as touch screens (automatic deposit and withdrawal machines) for ATM machines, trackpads for portable computers, and scroll wheels for multimedia players. The touch sensor detects the position or motion of an object moving along its surface, such as a finger or a stylus, to generate an electrical signal for subsequent circuit processing.

There are many types of touch sensing methods, such as resistive, capacitive, sonic, and light sensing. Wherein, the resistive touch sensor comprises two continuous resistance layers superposed on each other, and a plurality of spacers sandwiched in the two continuous resistance layers by a preset distance. In use, the object contacts a certain position of the surface of the touch sensor, and the two resistive layers contact each other at corresponding touch positions. The center coordinate of the touch position is obtained by detecting a change in the touch position current. However, if multiple touches occur, the resistive sensor cannot distinguish between multiple touch locations.

There are two types of capacitive touch sensors, projected capacitive and surface capacitive. The projected capacitive touch sensor includes a grid electrode pattern; the surface capacitance sensor includes a continuous conductive sheet and an electrode disposed at an edge of the continuous conductive sheet. When a conductive material such as a party metal or a finger approaches a capacitive touch sensor, the capacitive touch sensor determines a touch position by detecting a change in capacitance. However, the capacitive touch sensor cannot sense the touch of the insulator.

The acoustic touch sensor includes an acoustic wave emitting element and an acoustic wave receiving element that enable sound waves to be transmitted on the surface of the touch sensor. When the object contacts the surface, it absorbs part of the energy of the sound wave. The energy change can be detected to determine the touch location. The optical touch sensor works similarly to the acoustic touch sensor. The only difference is that it transmits light waves such as infrared rays instead of sound waves on the surface of the touch sensor. However, both of the above touch sensing devices require a mounting bracket to set the transmitting and receiving components. In addition, dust, oil and other contaminants will cause the touch sensor to be falsely sensed, which will reduce the sensitivity of the touch sensor.

It is an object of the present invention to provide an inductive touch sensor capable of detecting conductive objects and insulators.

The inductive touch sensor includes a driving layer, a sensing layer and at least one inductive circuit. The drive layer generates a magnetic field. The sensing layer is disposed facing the driving layer to sense the magnetic field to generate at least one inductive electrical signal. The inductive electrical signal represents a change in inductance of at least one touch position on the inductive touch sensor. The at least one inductive circuit is coupled to the driving layer and the sensing layer and detects the inductive electrical signal to determine the at least one touch position of the inductive touch sensor.

Another object of the present invention is to provide a method for detecting a touch position of an inductive touch sensor.

The detecting method comprises the steps of: a) applying a driving current to the driving layer, so that the driving layer generates a magnetic field, and the magnetic field causes an inductive layer to generate an inductance; b) generating at least one inductive electrical signal, The at least one inductive signal indicates at least one inductance change of the sensing layer when the inductive sensor is touched; c) transmitting the at least one inductive electrical signal to a controller; and d) transmitting the at least The processing of an inductive signal determines at least one touch location.

According to the present invention, an inductive touch sensor can detect both conductive and insulating materials to overcome the defects of the above touch sensor using the conventional touch sensing principle.

It is well known that magnetic lines of force are generated around a wire as it passes through the wire. The strength of the magnetic lines of force and the magnetic field depends on the shape of the guide and the current flow. If the second wire is close to the energized first wire, the magnetic force generated by the first wire will cause the second wire to generate inductance. Figure 1 shows how the two wires produce the physical properties of the inductor. A current 4 is applied to the wire 2 and causes the wire 2 to generate a magnetic field 3 around the wire 1. The magnetic field 3 causes the wire 1 to generate an inductance. The amount of inductance depends on the distance between the wires and other parameters. If the distance between the wires changes, the inductance will change. A signal 5 for indicating a change in inductance is output. The electrical signal 5 can be voltage, current, or the like. Therefore, detecting the change in inductance can determine the touch position at which the distance changes. The inductive inductor of the present invention operates based on the aforementioned sensing principle.

2a and 2b show an inductive inductor 100 in accordance with a first embodiment of the present invention. The inductive inductor 100 includes a driving layer 110, a sensing layer 120, and an inductive circuit 130. The driving layer 110 includes a plurality of driving electrodes 111, and the sensing layer 120 includes a plurality of sensing electrodes 121, wherein each driving electrode 111 faces each of the corresponding sensing electrodes 121. In order to keep the distance between the driving electrode 111 and the sensing electrode 121 from contacting each other, they are isolated by an insulating medium. The insulating medium can be a continuous insulating layer or a plurality of insulating spacers. Further, the insulating medium is a deformable material such as plastic, liquid glue or the like. Air can also be introduced into an inductive touch sensor for use as an insulating medium. A driving substrate 112 and a sensing substrate 122 are disposed to support the driving electrode 111 and the sensing electrode 121. The inductor circuit 130 includes a plurality of drive wires 131, a plurality of sense leads 132, and a controller 133. The driving wire 131 connects the driving electrode 111 to the controller 133 in the first direction on the driving substrate 112, and the sensing wire 132 connects the sensing electrode 121 to the controller 133 in the second direction on the sensing substrate 122.

In use, the controller 133 applies a drive current to the drive electrode 111 through the drive wire 131 to generate a magnetic field surrounding the drive electrode 111. This magnetic field acts on the sensing electrode 121 to generate an inductance. The inductance is a function of the distance between the sensing electrode 121 and the driving electrode 111. When one touch position of the outer surface of the drive substrate 112 on which the drive electrode 111 is disposed is touched, the drive substrate 112 is pressed to approach the sense substrate 122 on which the sense electrode 121 is disposed. The distance between the driving electrode 111 and the sensing electrode 121 at the touch position is reduced. This change in distance causes the change in inductance of the sensing electrode 121 to be output by the inductive wire 132 to the controller 133 in the form of an electrical signal to determine the touch position.

Referring to FIG. 3, the driving electrodes 111a, 111b, and 111c are located on the driving wire 131a, the driving electrodes 111d, 111e, and 111f are located on the driving wire 131b, and the driving electrodes 111g, 111h, and 111i are located on the driving wire 131c. Meanwhile, the sensing electrodes 121a, 121d, and 121g are located on the sensing wires 132a, the sensing electrodes 121b, 121e, and 121h are located on the sensing wires 132b, and the sensing electrodes 121c, 121f, and 121i are located on the sensing wires 132c. The drive wires 131a, 131b, and 131c are sequentially driven. After each of the driving wires 131a, 131b or 131c is driven, the sensing wires 132a, 132b and 132c are detected. For example, when a drive current passes through the drive wire 131a, the drive electrodes 111a, 111b, and 111c will generate a magnetic field to generate an inductance on the sense electrodes 121a, 121b, and 121c. If the outer surface above the driving electrode 111a is touched, the driving electrode 111a approaches the sensing electrode 121a. Since the pitch of the driving electrode 111a and the sensing electrode 121a at the touch position is reduced, the inductance of the sensing electrode 121a is enhanced and a corresponding inductive electrical signal is generated. The inductive electrical signal is sensed when the inductive lead 132a is detected. Therefore, the controller 133 determines the touch position based on the sensing wire 132a and the driving wire 131a.

As shown in FIGS. 4a-4c, the driving electrode 111 is disposed on the outer surface or the inner surface of the driving substrate 112, and the sensing electrode 121 is disposed on the outer surface or the inner surface of the sensing substrate 122. If the driving electrode 111 is disposed on the outer surface of the driving substrate 112 or the sensing electrode 121 is disposed on the outer surface of the sensing substrate 122, one or more outer covers (not shown) are required to be overlaid on the driving electrode 111 or the sensing electrode 121. To avoid them being scratched.

The drive and sense wires are not limited to straight lines. FIG. 5 shows an inductive touch sensor 200 according to a second embodiment of the present invention. The inductive touch sensor 200 includes a driving layer 210, a sensing layer 220, and an inductive circuit 230. The driving layer 210 includes a plurality of driving electrodes 211 and a driving substrate 212 supporting the driving electrodes 211. The sensing layer 220 includes a plurality of sensing electrodes 221 and a sensing substrate 222 supporting the sensing electrodes 221 . The inductor circuit 230 includes a plurality of driving wires 231, a plurality of sensing wires 232, and a controller 233. The driving wires 231 extend from different corners of the driving substrate 212 in different directions to cover the inner surface of the driving substrate 212, thereby connecting the driving electrodes 211 to the controller 233. At the same time, the sensing wires 232 are distributed on the inner surface of the sensing substrate 222 in a plurality of concentric arcs to connect the sensing electrodes 221 to the controller 233. The method for detecting the touch position in this embodiment is the same as the first embodiment. Based on the distribution of the drive wire 231 and the sense wire 232, the controller 233 determines the touch position by the polar coordinates determined by the arc radii of the drive wire 231 and the sense wire 232.

The driving wire intersection of the second embodiment of the present invention is not limited to a corner, and may be any point that drives the inner surface of the substrate. As with the second embodiment, as shown in Fig. 6, the third embodiment of the present invention determines the touch position based on the polar coordinates. The intersection of the drive wires 331 is located at the center of the inner surface of the drive substrate 312, and the inductive touch sensor 300 can also be assembled in another manner. The inductive touch sensor 300 includes a driving layer 310 having a driving substrate 312 and a plurality of driving electrodes 311, a sensing layer 320 having a driving substrate 322 and a plurality of sensing electrodes 321, and an inductive circuit 330. Unlike the second embodiment, the drive wires 331 of the inductor circuit 330 extend in different directions and intersect at the center of the inner surface of the drive substrate 312. A plurality of insulating sheets 340 are provided at the intersection of the driving wires 331 to isolate the driving wires 331. Since the intersection is located at the center, the inductive wires 332 of the inductive circuit 330 are a plurality of concentric circles that are centered on the center of the inner surface of the sensing substrate 322, instead of the concentric arc of the second embodiment. Other connection relationships are the same as those of the second embodiment.

In addition, the drive wires can be distributed in a concentric or concentric arc, and the inductive wires extend in different directions and meet at any point on the inner surface of the sensing substrate. It is worth noting that concentric circles and concentric arcs can be considered as different implementations of concentric circles.

In the first embodiment, the driving electrodes connected in the first direction and the sensing electrodes connected in the second direction are both used to determine the touch position. The invention also has another drive detection mechanism, that is, another plate electrode is used as the drive electrode for generating the magnetic field, and the sensing electrodes are divided into two groups to determine the touch position in two directions.

A fourth embodiment employing the other drive detection mechanism is shown in Figures 7a and 7b. The inductive touch sensor 400 includes a driving layer 410 having a driving electrode 411, a sensing layer 420 having a plurality of sensing electrodes, and an inductive circuit 430. The driving electrode 411 is a conductive plate and is disposed on the inner surface of the driving substrate 412. The sensing electrode is divided into a plurality of first sensing electrodes 421 disposed on the inner surface of the sensing substrate 422, and a plurality of second sensing electrodes 423 disposed on the outer surface of the sensing substrate 422. The inductor circuit 430 includes a controller 433, a driving wire 431, a plurality of first sensing wires 432, and a plurality of second sensing wires 434. The drive wire 431 connects the drive electrode 411 to the controller 433 to provide a drive current. The first sensing wire 432 connects the first sensing electrode 421 to the controller 433 in the first direction on the inner surface of the sensing substrate 422, and the second wire 434 connects the second sensing electrode 423 in the second direction to the outer surface of the sensing substrate 422 to control 433.

When a driving current is applied to the driving electrode 411 through the driving wire 431, the space between the first sensing electrode 421 and the driving electrode 411 is filled with the magnetic field caused by the driving current. An inductance is generated on the first sensing electrode 421 and the second sensing electrode 423. If a touch occurs on the outer surface of the drive substrate 412, the distance between the drive electrode 411 and the first sense electrode 421 will decrease at the touch position. The decrease in the distance will cause an increase in the inductance of the first sensing electrode 421, and the inductive electrical signal representing the increased inductance is transmitted to the controller 433 through the first sensing wire 432. The controller 433 calculates a touch position in the first direction based on the induced electrical signal of the first sensing electrode 421. At the same time, the driving electrode 411 is close to the first sensing electrode 421, and the distance between the driving electrode 411 and the second sensing electrode 423 provided on the outer surface of the sensing substrate 422 is reduced. Therefore, the touch position in the second direction can be obtained according to the same method. As with the first embodiment, the controller 433 determines the touch position based on the first sense wire 432 in the first direction and the second sense wire 434 in the second direction.

A further object of the present invention is to provide an inductive touch sensor 500, that is, a fifth embodiment. As shown in FIG. 8, the sensing electrodes are disposed on the same surface of the sensing substrate. In the fourth embodiment, the inductive touch sensor includes a driving layer 510 having a driving electrode 511, a sensing layer 520 having a plurality of first sensing electrodes 521 and a plurality of second sensing electrodes 523, and an inductive circuit. 530. The driving layer 510 is opposite to the sensing layer 520. The driving electrode 511 is a conductive plate provided on the inner surface of the driving substrate 512. The first sensing electrode 521 and the second sensing electrode 523 are both disposed on the inner surface of the sensing substrate 522. The inductor circuit 530 includes a controller, a driving wire 531, a plurality of first sensing wires 532, and a plurality of second sensing wires 534. The first sensing wire 532 connects the first sensing electrode 521 to the controller 533 in the first direction on the sensing substrate 522, and the second sensing wire 534 connects the second sensing electrode 523 to the controller 533 in the second direction on the sensing substrate 522. . The controller 533 is connected to the driving electrode 511 through a driving wire 531 to supply a driving current.

The first inductive wire 532 and the second inductive wire 534 cross each other. At the intersection, a plurality of insulating sheets 540 are disposed between the first sensing wires 532 and the second sensing wires 534 to be isolated from each other. The method of detecting the touch position is the same as that of the fourth embodiment. The inductive signal indicating the change in inductance is output to the controller 533 through the first inductive wire 532 in the first direction and the second wire 534 in the second direction. Therefore, the controller 533 determines the touch position in the first direction and the second direction. Also, the touch may be applied to the outer surface of the drive substrate 512 or the outer surface of the sense substrate 522.

As shown in the above embodiment, the controller is capable of determining the touch position on electrodes in two different directions. If independent coordinates are set for each sensing electrode, the touch position will be detected independently by each sensing electrode. 9a and 9b show an inductive touch sensor 600 according to a sixth embodiment of the present invention. The inductive touch sensor 600 includes a driving layer 610 having a driving electrode 611, a sensing layer 620 having a plurality of sensing electrodes 621, and an inductive circuit 630. The driving layer 610 is opposite to the sensing layer 620. The driving electrode 611 is disposed on the inner surface of the driving substrate 612, and the sensing electrode 621 is disposed on the inner surface of the sensing substrate 622. The inductor circuit 630 includes a controller 633, a driving wire 631 and a plurality of sensing wires 632. Each of the sensing electrodes 621 is connected to the controller 633 through a corresponding sensing wire 632, and the driving electrode 611 is connected to the controller 633 through a driving wire 631.

In the same manner as the above embodiment, the driving electrode 611 generates a magnetic field to cause the sensing electrode 621 to generate an inductance. When a touch occurs on the outer surface of the drive substrate 612, an inductive electrical signal representing a change in inductance of the sense electrode 621 is transmitted to the controller 633 to confirm the touch position. Since each of the sensing electrodes 621 is connected to the controller 633, the independent coordinates of the sensing electrodes 621 can directly indicate the touch position. As a result, each of the sensing electrodes 621 that produces a change in inductance can determine the touch position. In actual use, a touch operation may occur on the outer surface of the drive substrate 612 or the outer surface of the sense substrate 622.

In the present invention, the driving layer and the sensing layer should be separated by an insulating medium (not shown). Furthermore, the driving electrodes may be disposed on the inner surface or the outer surface of the driving substrate, or may be disposed on the inner and outer surfaces of the driving substrate at the same time. Similarly, the sensing electrodes may be disposed on the inner or outer surface of the sensing substrate, or may be disposed on the inner and outer surfaces of the sensing substrate. If the driving electrode is disposed on the outer surface of the driving substrate or the sensing electrode is disposed on the outer surface of the sensing substrate, one or more cover plates are disposed on the driving electrodes and the sensing electrodes to prevent them from being scratched.

Corresponding to different use environments, when the outer surface of the sensing layer in the above embodiment is touched, the sensing electrode is brought closer to the driving electrode.

In different touch devices, the inductive touch sensor can be opaque or transparent, such as a touch pad of a laptop computer and a touch screen of a mobile phone. Inductive sensing method, the touch sensor can detect the touch operation of the conductor or insulator in different sensing sensitivity environments.

The present invention provides at least one drive electrode and at least one sense electrode. The resolution and size of the inductive touch sensor are the main factors determining the number of electrodes. In general, the larger the required size, the higher the resolution and the more electrodes are needed. The number of drive and sense leads depends on the number of drive and inductor electrodes. In addition, the number of inductive circuits is affected by industrial design requirements.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; all other equivalent changes or modifications which are not departing from the spirit of the invention should be included in the following Within the scope of the patent application.

1, 2. . . wire

3. . . magnetic field

4. . . Current

5. . . Telecommunications

100, 200, 300, 400, 500, 600. . . Inductive touch sensor

110, 210, 310, 410, 510, 610. . . Drive layer

111, 111a, 111b, 111c, 111d, 111e, 111f, 111g, 111h, 111i, 211, 311, 411, 511, 611. . . Drive electrode

112, 212, 312, 412, 512, 612. . . Drive substrate

120, 220, 320, 420, 520, 620. . . Sensing layer

121, 121a, 121b, 121c, 121d, 121e, 121f, 121g, 121h, 121i, 221, 321, 621. . . Induction electrode

122, 222, 322, 422, 522, 622. . . Induction substrate

130, 230, 330, 430, 530, 630. . . Inductor circuit

131, 131a, 131b, 131c, 231, 331, 431, 531, 631. . . Drive wire

132, 132a, 132b, 132c, 232, 332, 632. . . Inductive wire

133, 233, 333, 433, 533, 633. . . Controller

340, 540. . . Insulating sheet

432, 532. . . First induction wire

434, 534. . . Second induction wire

421, 521. . . First sensing electrode

423, 523. . . Second sensing electrode

Figure 1 is a schematic diagram showing the generation of inductance between two wires;

2a is a cross-sectional view of an inductive touch sensor according to a first embodiment of the present invention;

2b is an exploded perspective view of the inductive touch sensor of FIG. 2a;

3 is a working principle diagram of the inductive touch sensor of FIGS. 2a and 2b;

4a-4c are cross-sectional views of the inductive touch sensor of the first embodiment including other accessories;

5 is an exploded perspective view of an inductive touch sensor according to a second embodiment of the present invention;

6 is an exploded perspective view of an inductive touch sensor according to a third embodiment of the present invention;

Figure 7a is a cross-sectional view of an inductive touch sensor in accordance with a fourth embodiment of the present invention;

Figure 7b is an exploded schematic view of Figure 7a;

8 is an exploded perspective view of an inductive touch sensor according to a fifth embodiment of the present invention;

Figure 9a is a cross-sectional view showing an inductive touch sensor of a sixth embodiment of the present invention;

Figure 9b is an exploded schematic view of Figure 9a.

100‧‧‧Inductive touch sensor

110‧‧‧Drive layer

111‧‧‧ drive electrode

112‧‧‧Drive substrate

120‧‧‧Sense layer

121‧‧‧Induction electrode

122‧‧‧Induction substrate

133‧‧‧ Controller

131‧‧‧Drive wire

132‧‧‧Induction wire

Claims (29)

An inductive touch sensor includes: a driving layer to generate a magnetic field; and a sensing layer disposed on the driving layer to be induced by the magnetic field to generate at least one inductive electrical signal, the inductive electrical signal Representing an inductance change of at least one touch position on the inductive touch sensor; and at least one inductive circuit connecting the driving layer and the sensing layer and detecting the inductive signal to determine the inductance The at least one touch position on the touch sensor. The inductive touch sensor of claim 1, wherein the sensing layer comprises a plurality of sensing electrodes to connect the at least one inductive circuit. The inductive touch sensor of claim 2, wherein the sensing layer further comprises a sensing substrate, and the sensing electrode is disposed on an inner surface of the sensing substrate. The inductive touch sensor of claim 2, wherein the sensing layer further comprises a sensing substrate, and the sensing electrode is disposed on an outer surface of the sensing substrate. The inductive touch sensor of claim 2, wherein the driving layer comprises at least one driving electrode connected to the at least one inductive circuit. The inductive touch sensor of claim 5, wherein the driving layer further comprises a driving substrate, and the at least one driving electrode is disposed on an inner surface of the driving substrate. The inductive touch sensor of claim 5, wherein the driving layer further comprises a driving substrate, and the at least one driving electrode is disposed on an outer surface of the driving substrate. The inductive touch sensor of claim 5, wherein the inductive circuit comprises: a controller; at least one driving wire connecting the at least one driving electrode to the controller; and a plurality of sensing a wire connecting the sensing electrode to the controller. The inductive touch sensor of claim 8, wherein the at least one driving wire is disposed along a first direction, and the sensing wire is disposed in a second direction different from the first direction. The inductive touch sensor of claim 8, wherein the at least one driving wire extends from at least one point in at least one direction, and the sensing wire is arranged to be concentric with the starting point as a center circle. The inductive touch sensor of claim 10, wherein the concentric circles are concentric circles or concentric arcs. The inductive touch sensor of claim 10, wherein the at least one driving wire comprises at least two driving wires, and the at least two driving wires extend from the starting point in different directions. The inductive touch sensor of claim 12, wherein the driving layer further comprises a plurality of insulating sheets disposed at intersections of at least two driving wires to insulate the driving wires from each other. The inductive touch sensor of claim 8, wherein the at least one driving wire further comprises at least two driving wires arranged in at least two concentric circles, the center of which is a starting point of the sensing wires extending in different directions . The inductive touch sensor of claim 14, wherein the concentric circles are concentric circles or concentric arcs. The inductive touch sensor of claim 14, wherein the sensing layer further comprises a plurality of insulating sheets disposed at intersections of the sensing wires to insulate the sensing wires from each other. The inductive touch sensor of claim 8, wherein the sensing wire is connected to the sensing electrode to the controller. The inductive touch sensor of claim 8, wherein the sensing electrode comprises a plurality of first sensing electrodes and a plurality of second sensing electrodes. The inductive touch sensor of claim 18, wherein the inductive wire comprises a plurality of first inductive wires connecting the first inductive electrode to the controller in a first direction, and along the Connecting the second sensing electrode to the plurality of second sensing wires of the controller in two directions. The inductive touch sensor of claim 19, wherein the first sensing electrode is disposed on an inner surface of the sensing substrate, and the second sensing electrode is disposed on an outer surface of the sensing substrate . The inductive touch sensor of claim 19, wherein the sensing layer further comprises a plurality of insulating sheets, and the insulating sheet is located between the first sensing wire and the second sensing wire And located at an intersection of the first sensing wire and the second sensing wire. The inductive touch sensor of claim 1, wherein the driving layer and the sensing layer are separated by an insulating medium. A method for detecting at least one touch position of an inductive touch sensor includes the following steps: a) applying a driving current to a driving layer to cause a magnetic field to be generated by the driving layer, and the magnetic field causes an induction The layer generates an inductance; b) generates at least one inductive electrical signal, the at least one inductive electrical signal indicating at least one inductance change of the sensing layer when the inductive sensor is touched; c) transmitting the at least one inductive The electrical signal to a controller; and d) determining at least one touch position by processing the at least one inductive electrical signal. The detecting method of claim 23, wherein the inductive touch sensor further comprises at least one driving wire connecting the driving layer to the controller, and connecting the sensing layer to the A plurality of sensing wires of the controller. The detecting method of claim 24, wherein the driving current is applied to the driving layer through the at least one driving wire. The detecting method of claim 25, wherein the at least one touch position is determined by the at least one driving wire and the sensing wire. The detecting method of claim 23, wherein the inductive touch sensor further comprises a plurality of first sensing wires and a plurality of second sensing wires connecting the sensing layer to the controller. The detecting method of claim 27, wherein the at least one touch position is determined by the first sensing wire and the second sensing wire. The detecting method of claim 23, wherein the touch position is located on an outer surface of the sensing layer.