CN110620575A - Touch knob switch - Google Patents

Abstract

The invention discloses a touch knob switch, which belongs to the field of electric fittings and solves the problem of unreliable operation of the touch knob switch in the prior art, and the technical scheme for solving the problem mainly comprises a first knob and a sensing part, wherein the first knob is provided with a first triggering metal body, the sensing part comprises a plurality of first sensing electrodes, the first sensing electrodes are respectively and electrically connected with a micro control unit, the first knob rotates relative to a panel to enable the first triggering metal body to be aligned with different first sensing electrodes to trigger corresponding first sensing electrodes, the first knob is connected to the panel through a first revolute pair and is axially limited on the outer surface of the panel, and the sensing part is positioned inside or inside the panel. The invention is mainly used for touch rotating operation of electrical appliances.

Description

A touch knob switch

technical field

The invention relates to electrical accessories, in particular to a touch knob switch.

Background technique

The rotary switch is used in many household appliances because of its simple and quick operation. However, the traditional rotary switch needs to be electrically connected to the circuit board control board, resulting in poor waterproof performance of the appliance. At the same time, the internal mechanical structure of the rotary switch will also be damaged. Due to the wear and tear of use, it is damaged and malfunctioned, and the overall service life is not good. For this reason, some companies have designed touch knobs. For example, invention patent 200920297818.9 discloses a control device for household appliances, in which a touch-type knob device is used instead of a traditional mechanical knob switch, which solves the problem of waterproofing of electrical appliances and wear of the knob switch. Specifically, a permanent magnet is installed on the circuit board, and the knob device is fixed on the panel through the mutual attraction between the fixed part installed on it and the permanent magnet. The fixed position of the main body is inaccurate, and the trigger position of the touch-sensitive components inside the knob switch is inaccurate. When using multiple touch-sensitive buttons at the same time, due to the instability of the rotation angle and displacement direction of the knob body, the corresponding sensor buttons cannot be accurately and effectively triggered. , the actual operability and accuracy are poor. In addition, the knob body is fixed by magnetic attraction, and the knob body is easy to drop and lose. When multiple knob devices are used, the magnets between different knob bodies interact with each other, resulting in a shift in the position of the knob bodies, which affects the user's use.

Contents of the invention

The object to be achieved by the present invention is to provide a touch knob switch, which is reliable and effective for user operation.

In order to achieve the above object, the present invention adopts the following technical solutions: a touch knob switch, including a first knob and a sensing part, the first knob is provided with a first trigger metal body, the sensing part includes a plurality of first sensing electrodes, the first sensing The electrodes are respectively electrically connected to the micro control unit, the first knob is rotated relative to the panel to align the first trigger metal body with different first sensing electrodes to trigger the corresponding first sensing electrodes, the first knob is connected to the panel through the first rotating pair and The axial limit is located on the outer surface of the panel, and the sensing part is located on the inner or inner surface of the panel.

As a preferred solution, the first rotating pair includes a first rotating shaft provided on the first knob and a first connecting seat provided on the outer surface of the panel, the first connecting seat is connected to the first rotating shaft and limits the first rotating shaft .

As a further preferred solution, the first connecting seat is provided with a first limit step, and the first rotating shaft is provided with a first limit protrusion that cooperates with the first limit step to achieve axial limit.

As a further preferred solution, the first knob is provided with a first positioning body, the first positioning body rotates with the first knob, the first connecting seat and/or the panel is provided with a plurality of first positioning protrusions, and the first positioning protrusions Distributed in a circle, a first positioning groove for accommodating a first positioning body is formed between two adjacent first positioning protrusions, and the first positioning body is located in the first positioning groove so that the first trigger metal body is aligned with the first sensing electrode.

As a preferred solution, the touch knob switch further includes a second knob, the second knob is connected to the panel through a second rotating pair and axially limited on the inner surface of the panel, and the second knob is provided with a second trigger metal body.

As a further preferred solution, the second knob rotates synchronously with the first knob, and the second trigger metal body and the first trigger metal body synchronously trigger the same first sensing electrode.

As a further preferred solution, the second rotating pair includes a second rotating shaft arranged on the second knob, the panel is provided with a through hole, the first rotating shaft and the second rotating shaft are fixed together so that the second rotating shaft and the first rotating shaft rotate synchronously or, the first knob is provided with a first magnet, and the second knob is provided with a second magnet, and the first magnet and the second magnet attract each other so that the second knob rotates synchronously with the first knob.

As a further preferred solution, the second knob and the first knob rotate independently, and the second rotating pair includes a second rotating shaft arranged on the second knob and a second connecting seat arranged on the inner surface of the panel, and the second connecting seat and The second rotating shaft is connected and the second rotating shaft is limited.

As a further preferred solution, the second knob is provided with a second positioning body, and the second positioning body rotates with the second knob, and the second connecting seat and/or panel is provided with a plurality of second positioning protrusions, and the second positioning body The protrusions are distributed in a ring, and a second positioning groove for accommodating the second positioning body is formed between two adjacent second positioning protrusions, and the second positioning body is located in the second positioning groove so that the second trigger metal body is aligned with the sensing part.

As a further preferred solution, the sensing part includes a plurality of second sensing electrodes, the second sensing electrodes are respectively electrically connected to the micro control unit, and the second knob is rotated relative to the panel so that the second trigger metal body is connected to the different second sensing electrodes. Align to trigger the corresponding second sensing electrodes.

As a further preferred solution, the second sensing electrode and the first sensing electrode are staggered from each other;

Alternatively, the second sensing electrode and the first sensing electrode are shielded from each other;

Alternatively, the micro control unit processes the sensing capacitance signal of the first sensing electrode in the closed state of the panel, and processes the sensing capacitance signal of the second sensing electrode in the open state of the panel.

As a further preferred solution, the second knob is rotated relative to the panel so that the second trigger metal body is aligned with a different first sensing electrode to trigger the corresponding first sensing electrode, and the first sensing electrode is aligned with the first trigger metal body to generate The inductive capacitance signal is C1, the inductive capacitance signal generated by the alignment of the first sensing electrode and the second trigger metal body is C2, the difference between C1 and C2 is greater than the detection sensitivity of the micro control unit, and the micro control unit is in the closed state of the panel Process C1, process C2 when the panel is open;

Alternatively, the second knob is rotated relative to the panel so that the second trigger metal body is aligned with a different first sensing electrode to trigger the corresponding first sensing electrode, and the micro-control unit processes the first trigger metal body to trigger the first sensing electrode when the panel is closed. The sensing capacitance signal of the sensing electrode, processing the sensing capacitance signal of the first sensing electrode triggered by the second trigger metal body in the open state of the panel;

Alternatively, the second knob is rotated relative to the panel so that the second trigger metal body is aligned with a different first sensing electrode to trigger the corresponding first sensing electrode, and the second trigger metal body triggers the first sensing electrode to stay at the same position as the first triggering metal body. The positions where the metal body triggers the first sensing electrodes to stay are staggered from each other.

After adopting the above technical solution, the present invention has the following advantages: the first rotary pair can form a kinematic cooperation relationship for the rotation of the first knob, and at the same time, the first knob can be axially limited, which can effectively position the first knob, so that the user can rotate the When the first knob is used, the first knob can be rotated in place accurately, so as to realize the accuracy and reliability of corresponding function control. Since the first knob is axially limited, the distance between the first trigger metal body and the first sensing electrode remains stable when the user rotates the first knob, so the sensing electrode triggers reliably without false triggering or non-triggering To ensure the effectiveness of user operations.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing:

FIG. 1 is a schematic structural view of Embodiment 1 of the present invention;

Fig. 2 is a schematic diagram of the first connecting seat in the first embodiment;

Fig. 3 is the schematic diagram of the first knob in the first embodiment;

4 is a schematic structural diagram of Embodiment 2 of the present invention;

FIG. 5 is a schematic structural diagram of Embodiment 3 of the present invention;

FIG. 6 is a schematic structural view of Embodiment 4 of the present invention;

Fig. 7 is a schematic diagram of adding a shielding plate on the basis of Fig. 6;

FIG. 8 is a schematic diagram of the distribution of the first sensing electrodes in Embodiment 8 of the present invention.

Detailed ways

Embodiment one:

As shown in FIG. 1 , the present invention provides a touch knob switch, which includes a first knob 1 and a sensing part. The touch knob switch is generally arranged on a panel 9 of an electrical appliance, and the sensing part is fixed on or inside the panel 9. The first The knob 1 is installed on the panel 9, the first knob 1 is provided with a first trigger metal body 11, the sensing part includes a plurality of first sensing electrodes 2, and the first sensing electrodes 2 are respectively electrically connected to the micro control unit, the first knob 1 is opposite to The panel 9 is rotated so that the first trigger metal body 11 is aligned with different first sensing electrodes 2 to trigger the corresponding first sensing electrodes 2. In order to make the first knob 1 not easy to lose, and at the same time, the user will not shift when operating, ensuring the rotation operation The position is reliable, so the first knob 1 is connected to the panel 9 through the first rotation pair and axially limited on the outer surface of the panel 9 , and the sensing part is located on the inside or inner surface of the panel 9 . The first rotation pair can form a kinematic cooperation relationship for the rotation of the first knob 1, and at the same time, the first knob 1 can be axially limited, which can effectively position the first knob 1, so that the user can accurately position the first knob 1 when rotating the first knob 1. A knob 1 is rotated in place to realize the accuracy and reliability of corresponding function control. Since the first knob 1 is limited in the axial direction, the distance between the first trigger metal body 11 and the first sensing electrode 2 remains stable when the user rotates the first knob 1, so the triggering of the sensing electrode is reliable and no error occurs. Triggered or not triggered, to ensure the validity of user actions.

In this embodiment, the first rotating pair includes the first rotating shaft 12 disposed on the first knob 1 and the first connecting seat 92 disposed on the outer surface of the panel 9, the first connecting seat 92 is connected to the first rotating shaft 12 and will The first rotating shaft 12 is limited. Specifically, a first limiting step 93 may be provided on the first connecting seat 92 , and the first rotating shaft 12 may be provided with a first limiting protrusion 13 that cooperates with the first limiting step 93 to realize axial limiting. The first limiting protrusion 13 can be arranged in sections, or in an annular structure. Conversely, a center hole is provided in the first rotating shaft 12, and the first connecting seat 92 extends into the center hole, and then the structure that the limit protrusion cooperates with the limit step can also be used to form a rotating pair, and the first knob 1 shaft to the limit.

As shown in Fig. 2, in order to allow the user to accurately rotate the first knob 1 for function selection, a first positioning body 14 can be provided on the first knob 1, the first positioning body 14 follows the rotation of the first knob 1, and the first connecting seat 92 is set There are a plurality of first positioning protrusions 94, and the first positioning protrusions 94 are distributed in a circle, and a first positioning groove for accommodating the first positioning body 14 is formed between two adjacent first positioning protrusions 94, and the first positioning body 14 is located in the The first trigger metal body 11 is aligned with the first sensing electrode 2 in the first positioning groove. The first positioning protrusion 94 can also be provided on the panel 9 , or be provided on both the first connecting seat 92 and the panel 9 . In this embodiment, the first positioning protrusions 94 are distributed circularly on one plane, in addition, the first positioning protrusions 94 may also be distributed along the circumferential surface and so on. In order to facilitate the user to observe the specific position to which the first knob 1 is currently rotated, an indicator arrow 10 can be set on the first knob 1, and a function indicator mark 90 can be set around the first knob 1 on the panel 9 accordingly. When the indicator arrow 10 is aligned with the corresponding When the function indicating mark 90 is displayed, it means that the first knob 1 is currently in the position of triggering the corresponding function. When the first positioning body 14 enters the first positioning groove, the indicating arrow 10 just aligns with a function indicating mark 90 . Only one end of the first positioning body 14 can enter the first positioning groove ( FIG. 2 ), or both ends can enter the first positioning groove at the same time ( FIG. 3 ).

When the user rotates the first knob 1, the first trigger metal body 11 rotates accordingly, and when the indicating arrow 10 is aligned with a certain function indicator mark 90, the first trigger metal body 11 is aligned with the first sensing electrode 2 corresponding to the current function indicator mark 90 , so that the first sensing electrode 2 is triggered, so as to realize the corresponding function selection.

The shape of the first knob 1 can be designed according to needs, such as circle, ellipse, square, cross or star and so on. The first knob 1 is generally made of non-conductive materials, such as plastic, wood, ceramics and other common materials.

Embodiment two:

Consider that the panel 9 of some electrical appliances has two states of open and closed, such as the cover plate of a wave-wheel washing machine. In order to allow the user to intuitively operate the touch knob switch when the panel 9 is opened and closed, this embodiment is improved on the basis of Embodiment 1. As shown in Figure 4, the touch knob switch also includes a second knob 3, the second knob 3 The second knob 3 is connected to the panel 9 through the second rotation pair and axially limited on the inner surface of the panel 9 , and the second knob 3 is provided with a second trigger metal body 31 .

In this embodiment, the second knob 3 rotates synchronously with the first knob 1 , and the second trigger metal body 31 and the first trigger metal body 11 trigger the same first sensing electrode 2 synchronously. In order to allow the second knob 3 to rotate synchronously with the first knob 1, the second rotary pair includes a second rotating shaft 32 arranged on the second knob 3, the panel 9 is provided with a through hole 99, and the first rotating shaft 12 and the second rotating shaft 32 are fixed. As a whole, the second knob 3 and the first knob 1 rotate synchronously. In this embodiment, the first rotating shaft and the second rotating shaft are directly fixed to form a rotation pair with the through hole, and the first knob and the second knob are axially limited by themselves and the panel, so that the first connecting seat can be omitted. It can be understood that the structure of the second rotating pair can also refer to the first rotating pair, and the two can adopt the same structure. In addition, the first rotating pair can also be used, that is, the connecting seat can not be provided to cooperate with the second rotating shaft 32, thereby simplifying The structure of the second rotating pair.

For other content not described in this embodiment, reference may be made to Embodiment 1.

Embodiment three:

In addition to fixing the first rotating shaft 12 and the second rotating shaft 32 into one body, as shown in FIG. The second magnets attract each other so that the second knob 3 and the first knob 1 rotate synchronously. In this way, there is no need to set through holes on the panel 9, reducing the process steps of panel 9 production, and ensuring the overall strength and waterproof and dustproof effect of the panel 9. In order to prevent the second knob 3 from detaching from the panel 9 , a second connecting seat 96 can be provided on the inner surface of the panel 9 , and the second connecting seat 96 is connected with the second rotating shaft 32 and limits the second rotating shaft 32 .

Other content not described in this embodiment can refer to Embodiment 2.

Embodiment four:

In addition to the synchronous rotation of the second knob 3 and the first knob 1, it is also possible to design the second knob 3 and the first knob 1 to rotate independently, so that the control of different functions under the open and closed states of the panel 9 can be realized accordingly, as shown in Fig. 6, No. The second rotation pair includes the second rotating shaft 32 disposed on the second knob 3 and the second connecting seat 96 disposed on the inner surface of the panel 9 , the second connecting seat 96 is connected to the second rotating shaft 32 and limits the second rotating shaft 32 .

The second knob 3 will realize function selection alone, so the structure of the first knob 1 can be referred to, the second knob 3 is provided with a second positioning body, the second positioning body follows the rotation of the second knob 3, and the second connecting seat 96 is provided with multiple A second positioning protrusion, the second positioning protrusions are distributed in a ring, and a second positioning groove for accommodating the second positioning body is formed between two adjacent second positioning protrusions, and the second positioning body is located in the second positioning groove so that the second positioning body is located in the second positioning groove. The two trigger metal bodies 31 are aligned with the sensing part. In this embodiment, the second positioning protrusions are distributed circularly on one plane, in addition, the second positioning protrusions may also be distributed along the circumferential surface and so on. The second positioning protrusion can also be provided on the panel 9 , or be provided on both the second connecting seat 96 and the panel 9 .

The sensing part includes a plurality of second sensing electrodes 4, the second sensing electrodes 4 are respectively electrically connected to the micro control unit, and the second knob 3 is rotated relative to the panel 9 so that the second trigger metal body 31 is aligned with different second sensing electrodes 4 to trigger Corresponding second sensing electrodes 4 . In order to prevent the second sensing electrode 4 and the first sensing electrode 2 from being triggered at the same time, the second sensing electrode 4 and the first sensing electrode 2 can be staggered from each other, that is, when the first trigger metal body 11 and the first sensing electrode 2 are aligned and triggered, It will not be aligned with the second sensing electrode 4, so it will not trigger the second sensing electrode 4, and when the second trigger metal body 31 is aligned with the second sensing electrode 4, it will not be aligned with the first sensing electrode 2, so it will not trigger The first sensing electrode 2. Of course, as shown in Figure 7, the second sensing electrode 4 and the first sensing electrode 2 can be directly shielded from each other through the shielding plate 98, so that the first trigger metal body 11 cannot trigger the second sensing electrode 4, and the second trigger metal Body 31 cannot trigger the first sensing electrode 2 .

In addition, a sensor for detecting the opening or closing of the panel 9 may also be used, and the micro-control unit only processes the sensing capacitance signal of the first sensing electrode 4 without processing the sensing capacitance signal of the second sensing electrode 4 in the closed state of the panel 9 . When the panel 9 is opened, only the sensing capacitance signal of the second sensing electrode is processed without processing the sensing capacitance signal of the first sensing electrode 2 .

For other content not described in this embodiment, reference may be made to the foregoing embodiments.

Embodiment five:

In addition to providing the second sensing electrode 4 , in order to reduce the cost, the second sensing electrode 4 may not be provided, and only the first sensing electrode 2 is provided. The second knob 3 is rotated relative to the panel 9 so that the second trigger metal body 31 is aligned with a different first sensing electrode 2 to trigger the corresponding first sensing electrode 2, and the induction generated by the alignment of the first sensing electrode 2 with the first trigger metal body 11 The capacitance signal is C1, the induction capacitance signal generated by the alignment of the first sensing electrode 2 and the second trigger metal body 31 is C2, the difference between C1 and C2 is greater than the detection sensitivity of the micro control unit, and the micro control unit is in the closed state of the panel 9 In this case, only C1 is processed but not C2, and only C2 is processed when the panel 9 is open and C1 is not processed.

For other content not described in this embodiment, reference may be made to the foregoing embodiments.

Embodiment six:

In addition to providing the second sensing electrode 4 , in order to reduce the cost, the second sensing electrode 4 may not be provided, and only the first sensing electrode 2 is provided. That is, the rotation of the second knob relative to the panel aligns the second trigger metal body with a different first sensing electrode to trigger the corresponding first sensing electrode to generate a sensing capacitance signal. By detecting the opening and closing state of the panel, the micro-control unit processes the inductive capacitance signal that the first trigger metal body triggers the first sensing electrode when detecting that the panel is in the closed state, since it can be known that the user rotates the first knob 1 to stop When the micro-control unit detects that the operation panel is in the open state, it processes the inductive capacitance signal that the second trigger metal body triggers the first inductive electrode, thereby judging that the user rotates the second knob 3 The operation information of the stop position is used to control the electrical appliances.

For other content not described in this embodiment, reference may be made to the foregoing embodiments.

Embodiment seven:

This embodiment is similar to the sixth embodiment, only the first sensing electrode 2 is provided, and the second knob is rotated relative to the panel to align the second trigger metal body with a different first sensing electrode to trigger the corresponding first sensing electrode. In order to prevent the second trigger metal body and the first trigger metal body from repeatedly triggering the same first sensing electrode 2, it can be designed that the position where the second trigger metal body triggers the first sensing electrode to stay is the same as the first trigger metal body triggers the first sensing electrode to stay. positions are staggered from each other. As shown in Figure 8, there are 8 first sensing electrodes, respectively 2a, 2b, 2c, 2d, 2e, 2f, 2g and 2h, and the first trigger metal body can only stay at 2a, 2c, 2e, 2g In the corresponding position, the second trigger metal body can only stay at the positions corresponding to 2b, 2d, 2f, and 2h, and the micro-control unit can judge the change of the sensing capacitance signal generated by the first sensing electrode at the corresponding position to determine that the user is operating the first One knob 1 or second knob 3.

For other content not described in this embodiment, reference may be made to the foregoing embodiments.

Except above-mentioned preferred embodiment, the present invention also has other implementation modes, those skilled in the art can make various changes and distortions according to the present invention, as long as not departing from the spirit of the present invention, all should belong to the defined in the claims of the present invention scope.

Claims (12)

1. A touch knob switch, comprising a first knob and a sensing part, the first knob is provided with a first trigger metal body, the sensing part includes a plurality of first sensing electrodes, the first sensing electrodes are respectively electrically connected to the micro control unit, the second A knob is rotated relative to the panel so that the first trigger metal body is aligned with different first sensing electrodes to trigger the corresponding first sensing electrodes. The outer surface of the panel, and the sensing part is located on the inner or inner surface of the panel. 2. The touch knob switch according to claim 1, wherein the first rotating pair comprises a first rotating shaft arranged on the first knob and a first connecting seat arranged on the outer surface of the panel, the first connecting seat It is connected with the first rotating shaft and limits the first rotating shaft. 3. The touch knob switch according to claim 2, characterized in that, the first connecting seat is provided with a first limit step, and the first rotating shaft is provided with a first limit step that cooperates with the first limit step to realize axial limit. A limit protrusion. 4. The touch knob switch according to claim 2, characterized in that, the first knob is provided with a first positioning body, the first positioning body rotates following the first knob, and the first connecting seat and/or panel is provided with multiple A first positioning protrusion, the first positioning protrusions are distributed in a ring, and a first positioning groove for accommodating the first positioning body is formed between two adjacent first positioning protrusions, and the first positioning body is located in the first positioning groove so that the second positioning body is located in the first positioning groove. A trigger metal body is aligned with the first sensing electrode. 5. The touch knob switch according to any one of claims 1 to 4, characterized in that, the touch knob switch further comprises a second knob, the second knob is connected to the panel through a second rotation pair and axially limited on the side of the panel On the inner surface, the second knob is provided with a second trigger metal body. 6. The touch knob switch according to claim 5, wherein the second knob rotates synchronously with the first knob, and the second trigger metal body and the first trigger metal body synchronously trigger the same first sensing electrode. 7. The touch knob switch according to claim 6, wherein the second rotating pair includes a second rotating shaft arranged on the second knob, the panel is provided with a through hole, and the first rotating shaft and the second rotating shaft are fixed as one Make the second knob rotate synchronously with the first knob; or, the first knob is provided with a first magnet, the second knob is provided with a second magnet, and the first magnet and the second magnet attract each other to make the second knob and the first knob Synchronized rotation. 8. The touch knob switch according to claim 5, characterized in that, the second knob and the first knob rotate independently, and the second rotation pair includes a second rotating shaft arranged on the second knob and an inner surface arranged on the panel The second connecting seat is connected with the second rotating shaft and limits the second rotating shaft. 9. The touch knob switch according to claim 8, characterized in that, the second knob is provided with a second positioning body, the second positioning body rotates following the second knob, and the second connecting seat and/or panel is provided with multiple A second positioning protrusion, the second positioning protrusions are distributed in a ring, and a second positioning groove for accommodating the second positioning body is formed between two adjacent second positioning protrusions, and the second positioning body is located in the second positioning groove so that the second positioning body is located in the second positioning groove. The second trigger metal body is aligned with the sensing part. 10. The touch knob switch according to claim 8, characterized in that, the sensing part includes a plurality of second sensing electrodes, the second sensing electrodes are respectively electrically connected to the micro control unit, and the rotation of the second knob relative to the panel makes the second The trigger metal body is aligned with different second sensing electrodes to trigger the corresponding second sensing electrodes. 11. The touch knob switch according to claim 10, characterized in that, the second sensing electrode and the first sensing electrode are staggered from each other; Alternatively, the second sensing electrode and the first sensing electrode are shielded from each other; Alternatively, the micro control unit processes the sensing capacitance signal of the first sensing electrode in the closed state of the panel, and processes the sensing capacitance signal of the second sensing electrode in the open state of the panel. 12. The touch knob switch according to claim 8, wherein the second knob is rotated relative to the panel so that the second trigger metal body is aligned with a different first sensing electrode to trigger the corresponding first sensing electrode, the first The sensing capacitance signal generated by the alignment of the sensing electrode and the first trigger metal body is C1, the sensing capacitance signal generated by the alignment of the first sensing electrode and the second trigger metal body is C2, and the difference between C1 and C2 is greater than the detection of the micro control unit Sensitivity, the MCU processes C1 when the panel is closed and C2 when the panel is open; Alternatively, the second knob is rotated relative to the panel so that the second trigger metal body is aligned with a different first sensing electrode to trigger the corresponding first sensing electrode, and the micro-control unit processes the first trigger metal body to trigger the first sensing electrode when the panel is closed. The sensing capacitance signal of the sensing electrode, processing the sensing capacitance signal of the first sensing electrode triggered by the second trigger metal body in the open state of the panel; Alternatively, the second knob is rotated relative to the panel so that the second trigger metal body is aligned with a different first sensing electrode to trigger the corresponding first sensing electrode, and the second trigger metal body triggers the first sensing electrode to stay at the same position as the first triggering metal body. The positions where the metal body triggers the first sensing electrodes to stay are staggered from each other.