A membrane switch for anti-ghosting computer keyboards

Abstract

This utility model relates to the field of computer keyboard technology and discloses an anti-ghosting computer keyboard membrane switch, including a membrane body. An upper wire is disposed inside the membrane body, and a middle partition layer is disposed on the lower surface of the upper wire. The outer wall of the middle partition layer is disposed inside the membrane body, and a circular hole is formed inside the middle partition layer. A lower wire is disposed on the lower surface of the middle partition layer, and the outer wall of the lower wire is disposed inside the membrane body. A conductive line is disposed inside the lower wire, and solder pads are fixedly connected to both outer walls of the conductive line. In this utility model, through the cooperation of the upper wire, middle partition layer, circular hole, lower wire, conductive line, solder pads, UV bridge, and surface mount, effective insulation and isolation are achieved, enhancing signal stability and anti-interference, reducing the probability of accidental touches, and simultaneously realizing a precise and reliable conduction triggering function, thereby effectively preventing ghosting.

Description

Technical Field

[0001] This utility model relates to the field of computer keyboard technology, and in particular to a membrane switch for an anti-ghosting computer keyboard. Background Technology

[0002] A computer keyboard is one of the most commonly used and primary input devices, typically composed of keys, keycaps, key switches, circuit boards, and a casing. It converts text symbols and commands into electrical signals that the computer can recognize, enabling interaction between the user and the computer. During keyboard use, membrane switches, as crucial input signal conversion components, directly impact the user experience, especially when pressing two or more keys simultaneously, causing other unpressed keys to appear. Therefore, anti-ghosting membrane switches are necessary for computer keyboards.

[0003] A search revealed Chinese patent publication number CN201910353U, which discloses a connection structure for a computer keyboard membrane switch. The structure includes upper and lower layer circuitry, with the upper and lower circuits printed on upper and lower insulating layers respectively. A partition is provided between the upper and lower circuits, and the partition has through holes for electrical connection between the circuits. The key feature is that the upper insulating layer and the upper layer circuitry printed thereon have recesses located within the through holes, with the upper layer circuitry on the lower end face of the recess connected to the lower layer circuitry for conduction. This connection structure improves upon existing connection methods, avoids their limitations, simplifies membrane switch design, saves space, and facilitates production control, thereby increasing production efficiency.

[0004] In the aforementioned utility model, signal transmission is achieved solely through physical contact between upper and lower layer circuits, without the inclusion of current limiting components. In actual operation, when pressing two or more keys simultaneously, signal crosstalk or interference signals may occur due to voltage fluctuations or current surges, resulting in the display of other unpressed keys and thus affecting the use of the keyboard. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides a membrane switch for anti-ghosting computer keyboards, which aims to improve the problem that when two or more keys are pressed at the same time, signal crosstalk or interference signals may be generated due to voltage fluctuations and current surges, resulting in the display of other keys that have not been pressed.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a membrane switch for an anti-ghosting computer keyboard, comprising a membrane body, an upper wire disposed inside the membrane body, a middle partition layer disposed on the lower surface of the upper wire, an outer wall of the middle partition layer disposed inside the membrane body, a circular hole being formed inside the middle partition layer, a lower wire disposed on the lower surface of the middle partition layer, an outer wall of the lower wire disposed inside the membrane body, a conductive line disposed inside the lower wire, and solder pads being fixedly connected to both outer walls of the conductive line.

[0007] The above technical solution involves a thin film body composed of an upper wire, a middle partition, and a lower wire. The upper and lower wires are used to implement wiring for the product matrix and structure. The circular holes inside the middle partition expose the key positions that need to be conductive, while also providing insulation for other circuits. The upper wire has grooves that correspond to the circular holes to prevent pressing on the thin film resistors, ensuring a flat structure and normal conductivity after the three layers of film are stacked. The conductive lines connect the keyboard keys to the control circuit, and the solder pads are used to solder and fix the thin film resistors.

[0008] As a further description of the above technical solution:

[0009] The upper surface of the pad is provided with a patch.

[0010] The above technical solution involves leaving a certain space on the pads for surface mount technology (SMT), and then connecting the SMT to the thin-film resistor.

[0011] As a further description of the above technical solution:

[0012] The upper surface of the patch is disposed on the lower surface of the partition layer.

[0013] With the above technical solution, the patch is mainly attached to the front end of the button circuit.

[0014] As a further description of the above technical solution:

[0015] The lower line is internally equipped with a bridged UV.

[0016] The above technical solution involves: due to space limitations in the lower structure, an insulation layer is installed on the line, and a bridge is added to the line.

[0017] As a further description of the above technical solution:

[0018] A thin-film resistor is provided on the upper surface of the patch.

[0019] The above technical solution involves attaching thin-film resistors to pads in a specific number to increase circuit resistance and reduce the current in the button circuit.

[0020] This utility model has the following beneficial effects:

[0021] 1. In this utility model, effective insulation and isolation are achieved through the cooperation between the upper line, middle partition, round hole, lower line, conductive line, solder pad, overpass UV and patch, which enhances signal stability and anti-interference, reduces the probability of accidental touch, and also realizes accurate and reliable conduction triggering function, thereby effectively preventing the occurrence of ghost key phenomenon. Attached Figure Description

[0022] Figure 1 This is a perspective view of a membrane switch for an anti-ghosting computer keyboard proposed in this utility model;

[0023] Figure 2 This is a partial structural diagram of the upper part of a membrane switch for an anti-ghosting computer keyboard proposed in this utility model;

[0024] Figure 3 This is a partial structural diagram of the middle layer of a membrane switch for an anti-ghosting computer keyboard proposed in this utility model;

[0025] Figure 4 This is a partial structural diagram of the lower part of the membrane switch for an anti-ghosting computer keyboard proposed in this utility model.

[0026] Legend:

[0027] 1. Thin film body; 2. Top line; 3. Intermediate layer; 4. Circular hole; 5. Bottom line; 6. Conductive circuit; 7. Pad; 8. Transition UV; 9. Patch. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Reference Figure 1 , Figure 3 and Figure 4This utility model provides an embodiment of an anti-ghosting computer keyboard membrane switch, comprising a membrane body 1, an upper wire 2 disposed inside the membrane body 1, a middle partition layer 3 disposed on the lower surface of the upper wire 2, an outer wall of the middle partition layer 3 disposed inside the membrane body 1, a circular hole 4 opened inside the middle partition layer 3, a lower wire 5 disposed on the lower surface of the middle partition layer 3, an outer wall of the lower wire 5 disposed inside the membrane body 1, a conductive line 6 disposed inside the lower wire 5, and solder pads 7 fixedly connected to both outer walls of the conductive line 6; a patch 9 disposed on the upper surface of the solder pad 7; and the upper surface of the patch 9 disposed on the lower surface of the middle partition layer 3.

[0030] Specifically, line 2 is the upper conductive film, containing the button electrode traces; line 3 is the insulating isolation film; hole 4 is the button conduction hole; and line 5 is the lower conductive film, containing the button circuit traces. The button KEY is connected through hole 4. The thin-film resistors are designed according to the number of buttons in the product, with one resistor attached to each button. The current in the button signal path is precisely controlled to prevent signal crosstalk between adjacent buttons. By independently setting a thin-film resistor at the front end of each button line, current limiting protection is introduced into each line, preventing multiple signals from interfering with each other. To suppress misjudgments at the source, and by setting the resistance value to 7K ohms, the wiring design becomes more standardized after unifying the resistance value of each key. If a key malfunctions, only its corresponding resistance point needs to be checked, facilitating repair or replacement. After the membrane switch is bonded with the membrane resistor, it undergoes high-temperature drying within the range of 125-130℃. After drying, the bonded membrane resistor is encapsulated with transparent UV glue or black encapsulating glue to fix the membrane resistor to the membrane switch. Utilizing the groove and round hole 4 inside the upper line 2, the membrane resistor portion is prevented from protruding during the three-layer membrane lamination. To prevent poor contact or deformation, a thin-film resistor with a total thickness of 0.1mm needs to be bonded. After mounting, the thin-film resistor should not exceed 0.5mm. It should be placed at the pad 7 reserved on the lower line 5. This is the location of the mounting plate 9. The thin-film resistor is mainly attached to the front end of the button circuit. Lower line 5 is part of the circuit matrix; each button is connected to the controller via a line segment. The thin-film resistor is not placed directly below the button, but rather on the line segment near the front end of the button contact, viewed from the controller's direction. This can also be understood as the electrical signal flowing from the control... The device transmits data to the transition section between the keys. The lower line 5 has a routing pattern, and the pad 9 is positioned on the line at the pad 7 using the conductive line 6 and the pad 7. This allows the thin film resistor to be attached above the lower line, that is, between the middle layer 3 and the lower line 5. Placing the resistor before the circuit conduction point can limit the current intensity of the channel, act as a buffer, and reduce signal crosstalk. This is a key measure to prevent ghosting. Furthermore, the conductive area of ​​the key cannot be blocked or raised. Placing the thin film resistor at the front end can avoid directly interfering with the physical and electrical behavior of the key being pressed.

[0031] Reference Figure 2 , Figure 3 and Figure 4 The lower line 5 has a cross-bridge UV8 inside; the upper surface of the patch 9 has a thin film resistor.

[0032] Specifically, due to the limited space in the lower circuit of membrane switches, some circuits inevitably cross or approach each other during the layout process. By using the UV8 bridge, two wires that should be short-circuited are physically and electrically isolated through spatial layering to ensure that they do not interfere with each other. When high-speed input or multiple keys are triggered simultaneously, electromagnetic interference may be generated between the circuits. Appropriate resistors can slow down current surges and reduce interference intensity. By embedding the film resistor at the front end of the key circuit, the resistance value of each key signal path can be effectively increased, thereby reducing current coupling between circuits and reducing the probability of false touches caused by parallel conduction, i.e., ghost keys. Since traditional anti-ghost key measures mainly rely on matrix circuit design and software recognition algorithms, the introduction of film resistors can avoid ghost keys at the circuit physical level, greatly simplifying the software processing logic and improving the response speed. Moreover, compared with complex multi-layer PCB wiring or diode solutions, the introduction of film resistors can achieve lower manufacturing costs by simplifying wiring and reducing cross complexity.

[0033] Working principle: When using this membrane, when the operator presses any key on the keyboard, the external pressing force is transmitted through the keycap and conductive adhesive to the switching area inside the membrane structure. This causes the upper line 2 and the lower line 5 to form mechanical contact and electrical connection at the KEY conduction window exposed at the circular hole 4 in the middle partition layer 3, forming a complete closed circuit path for key signal triggering. This causes the conduction line 6 to change from an open circuit to a closed state. By setting a component consisting of a patch 9 and a thin film resistor at the front end of each key circuit path and soldering it with the help of the pad 7, the thin film resistor is connected in series in each key circuit path to achieve electrical isolation of each key signal. When multiple keys are pressed at the same time, the current of different keys will not cross-influence, avoiding incorrect conduction and signal confusion. This avoids the ghost key effect caused by the simultaneous triggering of certain nodes in the matrix structure. Combined with the key value scanning logic of the control chip, it can effectively identify the real trigger key, thus successfully identifying the input and achieving no false touches, no interference, and no ghost keys.

[0034] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A membrane switch for an anti-ghosting computer keyboard, comprising a membrane body (1), characterized in that: The inner surface of the thin film body (1) is provided with an upper line (2), the lower surface of the upper line (2) is provided with a middle partition (3), the outer wall of the middle partition (3) is provided inside the thin film body (1), the middle partition (3) is provided with a circular hole (4), the lower surface of the middle partition (3) is provided with a lower line (5), the outer wall of the lower line (5) is provided inside the thin film body (1), the lower line (5) is provided with a conductive line (6), and the outer walls on both sides of the conductive line (6) are fixedly connected with pads (7).

2. The anti-ghosting membrane switch for a computer keyboard according to claim 1, characterized in that: The upper surface of the pad (7) is provided with a patch (9).

3. The anti-ghosting membrane switch for a computer keyboard according to claim 2, characterized in that: The upper surface of the patch (9) is disposed on the lower surface of the partition layer (3).

4. The anti-ghosting membrane switch for a computer keyboard according to claim 1, characterized in that: The lower line (5) is internally equipped with a bridge UV (8).

5. The anti-ghosting membrane switch for a computer keyboard according to claim 3, characterized in that: A thin-film resistor is provided on the upper surface of the patch (9).

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