Key switch and keyboard

Abstract

The utility model relates to the field of electronic input, in particular to a key switch and a keyboard. The key switch comprises a circuit board and a movable medium, the circuit board comprises a first body, an electrode hole, a first electrode, a second electrode and a capacitance detection circuit, the electrode hole is formed in the first body, and the first electrode and the second electrode are oppositely arranged in the electrode hole at intervals; the capacitance detection circuit detects capacitance between the first electrode and the second electrode; the movable medium comprises a second body, a first medium and a second medium, the first medium and the second medium are arranged on the second body, the second body reciprocates towards or away from the electrode hole in response to external physical pressure, the area, inserted into the electrode hole, of the first medium and the area, inserted into the electrode hole, of the second medium change along with the second body, and the change trends are opposite; the dielectric constants of the first medium and the second medium are different. The key switch provided by the utility model is simple in key triggering structure and convenient to assemble.

Description

Technical field

[0001] The utility model relates to the field of electronic input, in particular to a key switch and a keyboard. [Background Technology]

[0002] With the development of modern electronic technology, electronic products have gradually become more and more integrated into people's lives. Various electronic products, such as telephones, mobile phones, laptops, remote controls, etc., accompany people's daily lives. The input systems of these electronic products play a particularly important role. Capacitive buttons are currently widely used in the industry.

[0003] See also Figure 1 , which is a cross-sectional view and a partially enlarged view of a capacitive button in the prior art, shows that the capacitive button 90 includes a pressing body 93, an elastic body 95, a capacitive sensing unit 97, and a circuit board 99. Pressing the pressing body 93 changes the capacitance value of the capacitive sensing unit 97, thereby achieving key input.

[0004] The capacitive sensing unit 97 includes an adjustable electrode sheet 971, a capacitor dielectric 973, and a fixed electrode sheet 975 that are spaced apart and parallel to each other to form an adjustable capacitor. The adjustable electrode sheet 971 is a metal elastic sheet that abuts against the protrusion 933 of the pressing body 93. By pressing the pressing body 93, the abutment between the protrusion 933 and the adjustable electrode sheet 971 is released, and the adjustable electrode sheet 971 rebounds toward the capacitor dielectric 973, increasing the capacitance value of the capacitive sensing unit 97. Releasing the pressing body 93 restores the abutment between the protrusion 933 and the adjustable electrode sheet 971, resetting the adjustable electrode sheet 971, and restoring the capacitance value of the capacitive sensing unit 97.

[0005] It can be seen that in order to achieve the change of capacitance, the capacitance sensing unit 97 has a complex structure, the adjustment electrode sheet 971 needs to be precisely matched with the protrusion 933, and the assembly requirements are high. [Utility Model Content]

[0006] In order to solve the technical problems of the complex structure and high assembly requirements of the capacitive keys in the existing technology, the utility model provides a key switch and a keyboard for solving the above problems.

[0007] A push button switch includes a circuit board and an active medium. The circuit board includes a first body, an electrode hole, a first electrode, a second electrode, and a capacitance detection circuit. The electrode hole is provided in the first body, and the first electrode and the second electrode are provided in the electrode hole with a relative spacing. The capacitance detection circuit detects the capacitance between the first electrode and the second electrode. The active medium includes a second body, a first medium provided in the second body, and a second medium. In response to external physical pressure, the second body reciprocates toward or away from the electrode hole, and the areas of the first medium and the second medium inserted into the electrode hole change accordingly, with the change trends being opposite. The dielectric constants of the first medium and the second medium are different.

[0008] In some embodiments, the first medium and the second medium are arranged along the reciprocating motion direction of the second body, and in response to external physical pressure, the first medium and the second medium are alternately inserted into the electrode holes.

[0009] In some embodiments, the dielectric constant of the first medium is greater than the dielectric constant of the second medium, and the first medium is disposed on a side of the second medium close to the electrode hole.

[0010] In some embodiments, the first medium is a metal sheet.

[0011] In some embodiments, the electrode hole includes a plurality of sub-holes, two adjacent sub-holes are separated by an isolation groove or a spacer, and the first electrode and the second electrode are respectively disposed on surfaces of two different sub-holes.

[0012] In some embodiments, the push button switch also includes a fixed upper cover and a base, the upper cover and the base form a receiving space to accommodate the circuit board and the active medium, the bottom wall of the base is provided with a through hole corresponding to the active medium, and the side wall of the base is provided with a first limiting groove corresponding to the active medium, the first limiting groove penetrates the circuit board and is interconnected with the electrode hole and the through hole to slide and limit the active medium.

[0013] In some embodiments, the bottom wall of the base is provided with a second limiting groove corresponding to the movable medium and interpenetrating with the through hole.

[0014] In some embodiments, a first limiting protrusion is provided on the inner wall of the first limiting groove, a second limiting protrusion is provided on the inner wall of the second limiting groove, and the second limiting protrusion extends to the inner wall of the through hole.

[0015] In some embodiments, the push button switch further includes a cooperating fixed upper cover and a base, the upper cover and the base forming a receiving space to accommodate the circuit board and the active medium, the base including a fixing column, the circuit board further including a fixing hole, and the fixing column can be fixed to the fixing hole in a pluggable manner.

[0016] In some embodiments, the key switch is a mute switch, a low-axis switch, a paragraph switch and / or a light switch.

[0017] In some embodiments, the push button switch further includes an upper cover, a base, a pressing body and an elastic body. The upper cover and the base form a receiving space to accommodate the active medium, the pressing body and the elastic body. The base can be plugged in and fixed to the circuit board. The elastic body is clamped between the pressing body and the base. The active medium is fixed to the pressing body and moves synchronously with the pressing body.

[0018] A keyboard includes key switches arranged in an array and a control unit, the key switches including a circuit board and an active medium, the circuit board including a first body, an electrode hole, a first electrode, a second electrode, and a capacitance detection circuit, the electrode hole being provided in the first body, the first electrode and the second electrode being provided in the electrode hole with relative spacing, and the capacitance detection circuit detecting the capacitance between the first electrode and the second electrode; the active medium including a second body, a first medium provided in the second body, and a second medium, in response to external physical pressure, the second body reciprocating toward or away from the electrode hole, the area of ​​the first medium and the second medium inserted into the electrode hole changing accordingly, and the changing trends being opposite, the first medium and the second medium having different dielectric constants, the control unit being used to receive the detection result of the capacitance detection circuit and generate an input signal accordingly.

[0019] Compared with the prior art, the first electrode and the second electrode of the key switch provided by the present invention are arranged in the electrode hole of the circuit board, and the active medium is provided with the first medium and the second medium having different dielectric constants. In response to external physical pressure, the second body reciprocates toward or away from the electrode hole, and the area of ​​the first medium and the second medium inserted into the electrode hole changes accordingly, and the change trend is opposite, so that the capacitance between the first electrode and the second electrode changes accordingly. By detecting the capacitance between the first electrode and the second electrode by the capacitance detection circuit, the working state of the key switch can be determined. The key trigger structure is simple and easy to assemble.

Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Among them:

[0021] Figure 1 This is a cross-sectional view and a partially enlarged view of a capacitive button in the prior art;

[0022] Figure 2 This is a three-dimensional assembly diagram of a key switch provided by the utility model;

[0023] Figure 3 for Figure 2 The exploded perspective view and partial enlarged view of the key switch shown;

[0024] Figure 4 for Figure 3 A cross-sectional view of the base along the cutting line BB is shown;

[0025] Figure 5 for Figure 2 A partially exploded bottom view of the key switch shown;

[0026] Figure 6 for Figure 2 A cross-sectional view of the key switch along AA is shown;

[0027] Figure 7 for Figure 2 The schematic diagram of the relative position change of the circuit board and the active medium during the operation of the key switch shown;

[0028] Figure 8 for Figure 3 Another embodiment of the active medium is shown. [Specific implementation method]

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In this utility model, the term "at least one" refers to one or more, and "more than one" refers to two or more. The term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the related objects are in an "or" relationship.

[0031] The terms "first" and "second" are used solely for descriptive purposes, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. For example, a first XX could also be referred to as a second XX, and similarly, a second XX could also be referred to as a first XX, without departing from the scope of the embodiments of the present invention. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0032] See also Figure 2 and Figure 3 ,in, Figure 2 This is a three-dimensional assembly diagram of a key switch provided by the utility model. Figure 3 for Figure 2 The following is a schematic exploded perspective view and a partially enlarged view of a push button switch. The push button switch 10 includes a top cover 11, a base 12, a pressing body 15, an elastic body 16, a circuit board 17 with electrode holes 171, and an active medium 18. The top cover 11 and the base 12 cooperate to form a receiving space 110, which houses the pressing body 15, the elastic body 16, and the active medium 18. The base 12 is pluggable and fixed to the circuit board 17. The elastic body 16 is sandwiched between the pressing body 15 and the base 12. The active medium 18 is fixed to the pressing body 15 and freely extends through the electrode holes 171.

[0033] In this embodiment, the upper cover 11 and the base 12 can be fixed by snapping. The upper cover 11 has a guide hole 111 , and the pressing body 15 freely passes through the upper cover 11 through the guide hole 111 for pressing.

[0034] Please refer to Figure 4 and Figure 5 ,in, Figure 4 for Figure 3 The cross-sectional view of the base along the cutting line BB is shown. Figure 5 for Figure 1A partially exploded bottom view of the push switch shown. The base 12 includes a bottom wall 121, four side walls 122, a guide tube 123, a fixing post 124, a through-hole 125, a first limiting slot 126, and a second limiting slot 127. The bottom wall 121 is connected to one end of the four side walls 122. The guide tube 123 extends from the bottom wall 121 toward the upper cover 11. The fixing post 124 extends from the bottom wall 121 toward the circuit board 17. The circuit board 17 is provided with a corresponding fixing hole 173, and the fixing post 124 is pluggable and fixed to the fixing hole 173. The through-hole 125 is provided on the bottom wall 121 corresponding to the active medium 18. The first limiting slot 126 is provided on an opposite side wall of the four side walls 122 corresponding to the active medium 18. It passes through the circuit board 17 and is interconnected with the through-hole 125 and the electrode hole 171 to slidably limit the active medium 18. The movable medium 18 freely passes through the through hole 125 and the electrode hole 171 along the first limiting groove 126. The second limiting groove 127 is provided on the bottom wall 121 corresponding to the movable medium 18 and is in communication with the through hole 125.

[0035] In this embodiment, there are two second limiting grooves 127 , which are arranged along the extending direction of the through hole 125 .

[0036] Furthermore, a first limiting protrusion 1261 is provided on the inner wall of the first limiting groove 126 , and a second limiting protrusion 1271 is provided on the inner wall of the second limiting groove 127 . The second limiting protrusion 1271 extends to the inner wall of the through hole 125 .

[0037] In some embodiments, the base may be provided with a hook extending from the bottom wall toward the circuit board, and the circuit board may be provided with a corresponding slot to engage with the hook.

[0038] Please refer to Figure 3 and Figure 6 , Figure 6 for Figure 1 The push switch is shown in a cross-sectional view along line AA. The pressing body 15 includes a third body 151, a lead post 153, and a fixing member 155. The lead post 153 is formed by the third body 151 extending toward the base 12 in a direction corresponding to the lead tube 123. During assembly, it is inserted into the lead tube 123 and can slide along the lead tube 123 when subjected to external physical pressure.

[0039] The fixing member 155 is provided on the third body 151 and can be integrally formed with the third body 151. The movable medium 18 is fixed to the fixing member 155 so as to respond to external physical pressure and move synchronously with the pressing body 15. The fixing method of the movable medium 18 can be set according to actual needs. For example, the movable medium 18 can be embedded in the fixing member 155, the movable medium 18 can be fixed to the fixing member 155 by adhesive, the movable medium 18 and the fixing member 155 can be integrally formed, etc.

[0040] In this embodiment, please refer to Figure 3 The fixing member 155 includes a first side wall 1551, a second side wall 1553, a third side wall 1555, a fourth side wall 1556, and a through-groove 1557. The first side wall 1551, the second side wall 1553, the third side wall 1555, and the fourth side wall 1556 are sequentially connected to form the through-groove 1557. The first side wall 1551 and the third side wall 1555 are oppositely disposed and have opposing arc-shaped protrusions 15511.

[0041] The elastic body 16 is sandwiched between the bottom wall 121 and the third body 151, and is sleeved with the lead tube 123 to provide a restoring force. In this embodiment, the elastic body 16 is a spring. Preferably, the third body 151 and the bottom wall 121 are provided with grooves corresponding to the elastic body 16 to limit the elastic body 16, such as Figure 6 shown.

[0042] See also Figure 5 The circuit board 17 further includes a first body 174, a first electrode 175, a second electrode 176, and a capacitance detection circuit (not shown). The electrode hole 171 is provided in the first body 174, and the first electrode 175 and the second electrode 176 are provided in the electrode hole 171 with a spacing therebetween. The capacitance detection circuit detects the capacitance between the first electrode 175 and the second electrode 176.

[0043] The electrode hole 171 includes a plurality of sub-holes 1711 , and two adjacent sub-holes 1711 are separated by an insulating tape, an isolation groove or a spacer. The first electrode 175 and the second electrode 176 are respectively arranged on the surfaces of two different sub-holes 1711 to couple to form a capacitor.

[0044] It can be understood that the first electrode 175 and the second electrode 176 are made of conductive material and are separated by an insulating tape, an isolation groove or a spacer, so that the first electrode 175 and the second electrode 176 are insulated from each other. The first electrode 175 and the second electrode 176 are metal materials covering the electrode hole 171. The insulating tape refers to the inner wall of the electrode hole 171 between the first electrode 175 and the second electrode 176 being an insulating part or provided with an insulating material. The isolation groove refers to the inner wall of the electrode hole 171 between the first electrode 175 and the second electrode 176 being concave inward to form an insulating isolation groove, such as Figure 5 The spacer refers to the electrode hole 171 being directly separated by the spacer into a plurality of sub-holes 1711 that do not penetrate each other.

[0045] It should be noted that the portion of the active medium 18 inserted into the electrode hole 171 can be configured to be non-contacting with the first electrode 175 and the second electrode 176, or can be configured to be in contact with the first electrode 175 and the second electrode 176. Specifically, the first electrode 175 and the second electrode 176 need to be insulated from each other. When an insulating layer, such as an insulating oil layer, is provided on the surface of the first electrode 175 and the second electrode 176, the inserted portion of the active medium 18 can be configured to be in contact with the first electrode 175 and the second electrode 176. When the inserted portion of the active medium 18 is a non-conductive medium, the active medium 18 can be configured to be in contact with the first electrode 175 and the second electrode 176 when inserted. When the inserted portion of the active medium 18 is a conductive medium, such as a piece of hardware, which can be in direct contact with the inserted portion of the active medium 18, the inserted portion of the active medium 18 can be configured to be non-contacting with the first electrode 175 and the second electrode 176.

[0046] It should also be noted that the first electrode 175 and the second electrode 176 are metal layers covering the electrode hole 171, which can be made by copper plating, tin plating and other processes. It can be understood that according to the capacitance determination formula C = (εS) / (4πkd), where ε is the dielectric constant of the dielectric, S is the facing area of ​​the capacitor plates, d is the distance between the capacitor plates, and k is the electrostatic force constant. The facing area S of the capacitor plates will affect the size of the capacitance, and the area of ​​the metal layer forming the first electrode 175 and the second electrode 176 will affect the capacitance change between the first electrode 175 and the second electrode 176. The larger the area of ​​the metal layer forming the first electrode 175 and the second electrode 176, the larger the corresponding capacitance. When the dielectric constant is changed, the greater the capacitance change caused. The higher the accuracy of judging the working state of the key switch 10 by detecting the capacitance change. During actual operation, a person skilled in the art may adopt a conventional standard thickness for the thickness of the circuit board 17, set different lengths of the metal layers according to the required capacitance change and the capacitance determination formula, detect the capacitance change to determine the working state of the push switch 10, compare the determination result with the actual working state of the push switch 10, and preferably select a metal layer length with high accuracy.

[0047] It should also be noted that, in this embodiment, the shape of the electrode hole 171 is rectangular, and the shape of the insertion portion of the active medium 18 is adapted thereto. In other embodiments, according to actual needs, the shape of the electrode hole 171 can also be set to be elliptical, square, etc., which is not specifically limited here.

[0048] See also Figure 3 The movable medium 18 includes a second body 181, and a first medium 183 and a second medium 185 disposed within the second body 181. The second body 181 extends through the through-slot 1557 and includes an arcuate recess 1811 that engages with the arcuate protrusion 15511. The first medium 183 and the second medium 185 form an insertion portion. In response to external physical pressure, the second body 181 reciprocates toward or away from the electrode aperture 171, causing the areas of the first medium 183 and the second medium 185 inserted into the electrode aperture 171 to change accordingly, with the changes occurring in opposite directions. Consequently, the dielectric constants of the first medium 183 and the second medium 185 differ.

[0049] It can be understood that, according to the capacitance determination formula, the first dielectric 183 and the second dielectric 185 have different dielectric constants. When the area of ​​their insertion into the electrode hole 171 changes, the capacitance C0 between the first electrode 175 and the second electrode 176 will change accordingly. By detecting the change in capacitance C0, the operating state of the push switch 10 can be confirmed. For example, when the dielectric constant of the first dielectric 183 is greater than that of the second dielectric 185, the capacitance C0 increases as the insertion area of ​​the first dielectric 183 increases and the insertion area of ​​the second dielectric 185 decreases. When the insertion area of ​​the first dielectric 183 decreases and the insertion area of ​​the second dielectric 185 increases, the capacitance C0 decreases. When the dielectric constant of the first dielectric 183 is less than that of the second dielectric 185, the capacitance C0 decreases as the insertion area of ​​the first dielectric 183 increases and the insertion area of ​​the second dielectric 185 decreases. When the insertion area of ​​the first dielectric 183 decreases and the insertion area of ​​the second dielectric 185 increases, the capacitance C0 increases.

[0050] See also Figure 7 ,for Figure 2 The diagram shows the relative position changes between the circuit board and the active medium during operation of the key switch. In this embodiment, the first medium 183 and the second medium 185 are arranged along the reciprocating motion direction of the second body 181. In response to external physical pressure, the first medium 183 and the second medium 185 are alternately inserted into the electrode hole 171. The dielectric constant of the first medium 183 is greater than that of the second medium 185. The first medium 183 is located on the side of the second medium 185 closer to the electrode hole 171. When not pressed, the second medium 185 is inserted into the electrode hole 171. When the pressing body 15 is pressed, the second body 181 moves toward the electrode hole 171. The area of ​​the first medium 183 inserted into the electrode hole 171 increases, while the area of ​​the second medium 185 inserted into the electrode hole 171 decreases, and the capacitance C0 decreases. When the pressing body 15 is released, the second body 181 moves away from the electrode hole 171 , the area of ​​the first medium 183 inserted into the electrode hole 171 becomes smaller, and the area of ​​the second medium 185 inserted into the electrode hole 171 becomes larger, and the capacitance C0 increases.

[0051] It should be noted that, when two adjacent sub-holes 1711 are separated by a spacer, a space is provided between the first medium 183 and the second medium 185 corresponding to the spacer.

[0052] In some embodiments, the first medium and the second medium are conductive media with different dielectric constants.

[0053] In some embodiments, the first medium is an insulating medium, and the second medium is a conductive medium.

[0054] In some embodiments, the second body and the first medium are a conductive medium with an integrated structure, a through hole is provided in the conductive medium, and air forms the second medium.

[0055] In some embodiments, the second body and the first medium are a metal sheet with an integrated structure, a through hole is provided in the metal sheet, and air forms the second medium.

[0056] In some embodiments, the first medium is a metal sheet, and the second medium is a plastic sheet.

[0057] In some embodiments, see Figure 8 ,for Figure 3 Another embodiment of the movable medium is shown in FIG. The first medium 283 and the second medium 285 are triangular in shape, and along the reciprocating direction of the second body 281 , the length variation trends of the horizontal line intercepted by the first medium 283 and the second medium 285 are opposite.

[0058] In some embodiments, the key switch is a short-axis switch, and the pressing stroke of the pressing body is short.

[0059] In some embodiments, the lead column is arranged on one side of the bottom wall, the lead tube is correspondingly arranged on one side of the third body, a light source is arranged at the center of the base, and the push button switch is a light-emitting switch.

[0060] In some embodiments, the lead column is arranged at the center of the bottom wall, the lead tube is correspondingly arranged at the center of the third body, a light source is arranged on one side of the base, and the push button switch is a light-emitting switch.

[0061] In some embodiments, the key switch is provided with a spring sheet, which is fixed to the base and elastically abuts against the third body to generate a paragraph sense. The key switch is a paragraph switch.

[0062] In some embodiments, a silent pad is provided on the key switch, which is clamped between the third body and the upper cover and / or between the pressing body and the lead tube, and the key switch is a silent switch.

[0063] The utility model also provides a keyboard, which includes key switches and a control unit arranged in an array. The key switches use the above-mentioned key switches. The control unit can be arranged on the above-mentioned circuit board. The control unit is used to receive the detection results of the above-mentioned capacitance detection circuit and generate corresponding input signals.

[0064] Compared with the prior art, the first electrode and the second electrode of the key switch provided by the present invention are arranged in the electrode hole of the circuit board, and the active medium is provided with the first medium and the second medium having different dielectric constants. In response to external physical pressure, the second body reciprocates toward or away from the electrode hole, and the area of ​​the first medium and the second medium inserted into the electrode hole changes accordingly, and the change trend is opposite, so that the capacitance between the first electrode and the second electrode changes accordingly. By detecting the capacitance between the first electrode and the second electrode by the capacitance detection circuit, the working state of the key switch can be determined. The key trigger structure is simple and easy to assemble.

[0065] Furthermore, the movable medium is coupled to the first electrode and the second electrode, and the base and the circuit board are fixed via the fixing holes and the fixing columns, thereby realizing hot plugging.

[0066] The above is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements are all within the scope of protection of the present invention.

Claims

1. A push button switch, characterized in that: include: A circuit board comprising a first body, an electrode hole, a first electrode, a second electrode, and a capacitance detection circuit, wherein the electrode hole is provided in the first body, the first electrode and the second electrode are provided in the electrode hole with a relative spacing, and the capacitance detection circuit detects the capacitance between the first electrode and the second electrode; The movable medium includes a second body, a first medium disposed in the second body, and a second medium. In response to external physical pressure, the second body reciprocates toward or away from the electrode hole, and the areas of the first medium and the second medium inserted into the electrode hole change accordingly, and the change trends are opposite. The dielectric constants of the first medium and the second medium are different.

2. The key switch according to claim 1, wherein: The first medium and the second medium are arranged along the reciprocating motion direction of the second body. In response to external physical pressure, the first medium and the second medium are alternately inserted into the electrode holes.

3. The key switch according to claim 1, wherein: The second body and the first medium are a conductive medium with an integrated structure. A through hole is provided in the conductive medium, and air forms the second medium.

4. The key switch according to claim 1, wherein: The dielectric constant of the first medium is greater than the dielectric constant of the second medium, and the first medium is arranged on a side of the second medium close to the electrode hole.

5. The key switch according to claim 1, wherein: The first medium is a metal sheet.

6. The key switch according to claim 1, wherein: The electrode hole includes a plurality of sub-holes, and two adjacent sub-holes are separated by an insulating tape, an isolation groove or a spacer. The first electrode and the second electrode are respectively arranged on surfaces of two different sub-holes.

7. The key switch according to claim 1, wherein: The push button switch also includes a fixed upper cover and a base. The upper cover and the base form a receiving space to accommodate the circuit board and the active medium. The bottom wall of the base is provided with a through hole corresponding to the active medium. The side wall of the base is provided with a first limiting groove corresponding to the active medium. The first limiting groove penetrates the circuit board and is interconnected with the electrode hole and the through hole to slide and limit the active medium.

8. The key switch according to claim 7, wherein: The bottom wall of the base is provided with a second limiting groove corresponding to the movable medium and interpenetrating with the through hole.

9. The key switch according to claim 8, characterized in that: A first limiting protrusion is provided on the inner wall of the first limiting groove, and a second limiting protrusion is provided on the inner wall of the second limiting groove, and the second limiting protrusion extends to the inner wall of the through hole.

10. The key switch according to claim 1, wherein: The key switch also includes a top cover and a base that are fixed together. The top cover and the base form a receiving space to accommodate the circuit board and the active medium. The base includes a fixing column, and the circuit board also includes a fixing hole. The fixing column can be fixed to the fixing hole in a pluggable manner.

11. The key switch according to claim 1, wherein: The key switch is a mute switch, a short axis switch, a paragraph switch and / or a luminous switch.

12. A keyboard comprising key switches and a control unit arranged in an array, characterized in that: The key switch is the key switch according to any one of claims 1 to 11, and the control unit is used to receive the detection result of the capacitance detection circuit and generate an input signal accordingly.

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