Anti-ghost keyboard circuit board

Abstract

The utility model discloses an anti-ghost keyboard circuit board, which comprises an upper circuit layer, a lower circuit layer and a middle interlayer, an upper circuit is arranged on the upper circuit layer, a lower circuit is arranged on the lower circuit layer, the middle interlayer is fixedly clamped between the upper circuit layer and the lower circuit layer, a plurality of middle layer holes are arranged on the middle interlayer, and the middle layer holes are communicated with the upper circuit layer and the lower circuit layer. A plurality of lower conductive points are arranged on a lower circuit of the lower circuit layer at intervals, a plurality of branch-shaped bypasses are led out of an upper circuit of the upper circuit layer at intervals, an upper conductive point is arranged at the tail end of each bypass, and the upper conductive points, the lower conductive points and the middle layer holes are arranged in a one-to-one opposite mode. The corresponding bypass can be deformed by pressing a pressing point position, corresponding to the upper conductive point, on the upper circuit layer, so that the upper conductive point at the end of the bypass is in contact conduction with the lower conductive point through the middle layer hole in the middle interlayer to form an input signal. Uncontrollable operation instructions caused by keyboard signal input errors are avoided, and normal use of the keyboard is guaranteed.

Description

Technical Field

[0001] The utility model relates to a switch, in particular to an anti-ghosting keyboard circuit board. Background Art

[0002] Keyboard circuit boards all use membrane switches. Conventional membrane switches generate a third-party input signal when three or more target keys are pressed simultaneously. For example, as shown in the figure below, when long-pressing the a key (PIN 1 and PIN 3), the b key (PIN 2 and PIN 3), and the c key (PIN 1 and PIN 4) simultaneously, the d key (PIN 2 and PIN 4) functions as it does, even though the d key is not pressed. This is known as a "ghosting" phenomenon.

[0003] In addition, when pressing the target key, the finger may touch other keys nearby, which will also cause multiple input signals, which falls into the category of false touch.

[0004] Both of the above situations will lead to the triggering of additional signals, which will cause keyboard signal input errors and thus uncontrollable operation instructions. Utility Model Content

[0005] In order to make up for the above deficiencies, the present invention provides an anti-ghosting keyboard circuit board, which effectively solves the problem of "ghosting" of keyboard membrane switches and the problem of false touches generating redundant input signals.

[0006] The technical solution adopted by the present invention to solve its technical problems is: an anti-ghosting keyboard circuit board, comprising an upper circuit layer, a lower circuit layer and a middle partition layer, wherein the upper circuit layer is provided with an upper circuit, the lower circuit layer is provided with a lower circuit, the middle partition layer is fixedly clamped between the upper circuit layer and the lower circuit layer, a plurality of middle-layer holes are provided on the middle partition layer, a plurality of lower conductive points are provided at intervals on the lower circuit on the lower circuit layer, a plurality of branch-shaped bypasses are led out at intervals on the upper circuit of the upper circuit layer, an upper conductive point is provided at the end of each bypass, the upper conductive point, the lower conductive point and the middle-layer holes are arranged one by one in direct opposition, and pressing a pressing point on the upper circuit layer corresponding to an upper conductive point can deform the corresponding bypass, thereby causing the upper conductive point at the end of the bypass to contact and conduct with the lower conductive point through the middle-layer hole on the middle partition layer, thereby forming an input signal.

[0007] As a further improvement of the present invention, a plurality of bypasses on the upper circuit layer are arranged at intervals along the same straight line, and the roots of adjacent bypasses are connected in series through a U-shaped circuit.

[0008] As a further improvement of the present invention, each bypass is provided with a high-impedance carbon strip of a fixed length, and the high-impedance carbon strip is connected in series with the upper conductive point. An input signal current intensity detection module and a multi-key judgment module are provided in the computer system. The input signal current intensity detection module can detect the current intensity of the input signal formed by the contact between the upper conductive point and the lower conductive point. The input signal current intensity detection module can transmit the current intensity data to the multi-key judgment module. The multi-key judgment module can compare the current intensity detected by the input signal current intensity detection module with the pre-stored single-key pressing current intensity and determine whether it is a multi-key pressing.

[0009] As a further improvement of the present invention, the high-impedance carbon strip is formed on the upper circuit on the surface of the upper circuit layer by printing high-impedance carbon paste.

[0010] As a further improvement of the present invention, the high-impedance carbon strip enables the resistance value of a single key loop formed by the contact between a single upper conductive point and a lower conductive point to be 2500 ohms to 7000 ohms.

[0011] As a further improvement of the present invention, the upper conductive dots and the lower conductive dots are both conductive silver dots formed by solidifying conductive silver paste.

[0012] As a further improvement of the present invention, the upper circuit, bypass and upper conductive points are formed on the surface of the upper circuit layer by printing and drying, and the lower circuit and lower conductive points are formed on the surface of the lower circuit layer by printing and drying.

[0013] As a further improvement of the present invention, the upper circuit layer and the lower circuit layer are made of flexible film materials, and the middle separator is a sheet structure formed by sequentially pre-shrinking, striping, punching middle layer holes and cutting of a T-substrate.

[0014] The beneficial technical effect of the present invention is as follows: the present invention prints a bypass on the upper circuit layer, the bypass is branched out from the upper circuit, and a conductive point is printed on the end of the bypass. When the pressing point of the upper circuit layer that is opposite to the upper conductive point is pressed, the upper conductive point is lowered and the bypass is pulled down at an angle, which does not cause the upper circuit to be tilted down. Therefore, the upper conductive point next to it will not be pulled down. Even if three pressing points are pressed at the same time, causing the three upper conductive points to drop at the same time, the fourth upper conductive point will not be pulled down, thereby avoiding the occurrence of the "ghosting" phenomenon when the keyboard is in use. In addition, the present invention also prints a pressure relief on the bypass. The fixed-length high-impedance carbon strip reduces the resistance of each key's loop circuit from low resistance (0 to 500 ohms) to high resistance (2500 ohms to 7000 ohms). Under equal voltage conditions, the current intensity of the key circuit becomes weaker, and the single-key signal current at this time is used as a standard current intensity. When multiple target keys are pressed at the same time or extra keys are accidentally touched, the input signal current intensity will change significantly. At this time, the computer system can automatically identify it as a multi-key press based on the standard signal strength through the scanning program, and no redundant signals will be generated. Therefore, it will not cause keyboard signal input errors and uncontrollable operation instructions, ensuring the normal use of the keyboard. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a cross-sectional diagram of the membrane switch structure principle;

[0016] Figure 2 It is the design principle diagram of the upper circuit and the lower circuit in the prior art;

[0017] Figure 3 This is a design principle diagram of the upper circuit and the lower circuit of the utility model. DETAILED DESCRIPTION

[0018] Embodiment: An anti-ghosting keyboard circuit board includes an upper circuit layer 1, a lower circuit layer 2, and a middle partition layer 3. The upper circuit layer 1 is provided with an upper circuit 12, and the lower circuit 22 layer is provided with a lower circuit 22. The middle partition layer 3 is fixedly clamped between the upper circuit layer 1 and the lower circuit layer 2. The middle partition layer 3 is provided with a plurality of middle-layer holes 31. The lower circuit 22 on the lower circuit 22 layer is provided with a plurality of lower conductive dots 21 at intervals. The upper circuit 12 of the upper circuit layer 1 is led out at intervals. The end of each bypass 13 is provided with an upper conductive dot 11. The upper conductive dot 11, the lower conductive dot 21, and the middle-layer holes 31 are arranged one by one opposite each other. Pressing a pressing point on the upper circuit layer 1 corresponding to the upper conductive dot 11 can deform the corresponding bypass 13, thereby causing the upper conductive dot 11 at the end of the bypass 13 to contact and conduct with the lower conductive dot 21 through the middle-layer hole 31 on the middle partition layer 3, thereby generating an input signal.

[0019] The upper and lower sides of the middle partition layer 3 are bonded and fixed to the upper circuit layer 1 and the lower circuit layer 2 by the adhesive layer 4. The adhesive layer is provided with an avoidance hole 41 corresponding to the middle layer hole 31. When the key is pressed, the key is pressed down on the pressing point on the upper circuit layer 1 that is opposite to the upper conductive point 11. The upper circuit layer 1 at this position is deformed and lowered, thereby causing the upper conductive point 11 to contact the lower conductive point 21 to form a conductive loop. The current flowing through the conductive loop forms an input signal. The computer system can recognize the input signal. Since each upper conductive point 11 is connected to the end of the bypass 13 Therefore, the descent of the upper conductive point 11 will only cause the corresponding bypass 13 to sink to a certain extent, and will not cause the position of the upper circuit 12 to sink. Therefore, the position of the unpressed upper conductive point 11 will not be pulled down. Even if the a key (PIN1 and PIN3), the b key (PIN2 and PIN3), and the c key (PIN1 and PIN4) are pressed simultaneously, the d key (PIN2 and PIN4) will not be triggered, and the function of the d key will not be generated, thereby avoiding the occurrence of the "ghosting" phenomenon when the keyboard is in use.

[0020] On the upper circuit layer 1, a plurality of bypasses 13 are arranged along the same straight line at intervals, and the roots of adjacent bypasses 13 are connected in series via a U-shaped circuit 14. This ensures that each upper conductive point 11 is positioned on the keyboard while occupying a small space and preventing adjacent upper conductive points 11 from being pulled.

[0021] Each bypass 13 is provided with a high-impedance carbon strip 15 of a fixed length, and the high-impedance carbon strip 15 is connected in series with the upper conductive point 11. The computer system is provided with an input signal current intensity detection module and a multi-key judgment module. The input signal current intensity detection module can detect the current intensity of the input signal formed by the contact between the upper conductive point 11 and the lower conductive point 21. The input signal current intensity detection module can transmit the current intensity data to the multi-key judgment module. The multi-key judgment module can compare the current intensity detected by the input signal current intensity detection module with the pre-stored single-key pressing current intensity and determine whether it is a multi-key pressing.

[0022] A high-impedance carbon strip 15 is added to the key circuit, which greatly increases the resistance value in the key circuit. Under the condition of equal voltage, the current intensity of the key circuit becomes weaker, and the single-key signal current at this time serves as a standard current intensity; when multiple target keys are pressed at the same time or extra keys are accidentally touched, a parallel circuit is formed, and the resistance value of the parallel circuit is equally attenuated, thereby causing the input signal current intensity to change significantly. At this time, the computer system can automatically identify it as a multi-key press based on the standard signal strength through the scanning program, and no redundant signals will be generated. Therefore, it will not cause keyboard signal input errors and uncontrollable operation instructions, ensuring the normal use of the keyboard.

[0023] The high-impedance carbon strips 15 are formed by printing high-impedance carbon paste onto the upper circuit surface of the upper circuit layer 1. Conventional screen printing can be used to print the high-impedance carbon paste onto the upper circuit layer 1. After drying and curing, the high-impedance carbon strips 15 are formed. The length of the high-impedance carbon strips 15 can be maintained consistent due to printing, thus enabling a controllable impedance range and high mass production feasibility.

[0024] The high-impedance carbon strip 15 ensures that the resistance of a single key circuit formed by the contact between the upper conductive point 11 and the lower conductive point 21 is between 2500 ohms and 7000 ohms. The resistance of the high-impedance carbon strip 15 can be determined based on the design requirements, and the printed length can be adjusted accordingly.

[0025] The upper conductive dots 11 and the lower conductive dots 21 are both conductive silver dots formed by solidifying conductive silver paste.

[0026] The upper circuit, bypass and upper conductive points are formed on the surface of the upper circuit layer by printing and drying, and the lower circuit and lower conductive points are formed on the surface of the lower circuit layer by printing and drying.

[0027] The upper circuit layer and the lower circuit layer are made of flexible film materials, and the middle barrier layer is a sheet structure formed by sequentially pre-shrinking, striping, punching middle-layer holes and cutting a T-base material.

[0028] The above-mentioned method for manufacturing an anti-ghosting keyboard circuit board comprises the following steps:

[0029] Step 1: The PET substrate is sequentially processed through the steps of pre-shrinking, slitting, punching the middle layer hole 31 and winding to form a middle layer coil. The middle layer coil is cut to form the middle layer 3 with the middle layer hole 31;

[0030] Step 2: The film is first automatically cut into upper and lower circuit layers through fixed-length drawing and CCD scanning positioning. Then, through the preheating, circuit printing and baking steps, the upper circuit 12, bypass 13 and upper conductive dots 11 are printed on the surface of the upper circuit layer 1, and the lower circuit 22 and lower conductive dots 21 are printed on the surface of the lower circuit layer 2. After the upper and lower circuit layers 1 and 2 are printed, ATE testing is first performed to ensure the printing quality of the upper circuit 12 and lower circuit 22.

[0031] Step 3: Printing high-impedance carbon strips 15 on the surface of the upper circuit layer 1;

[0032] Step 4: Punch and cut the printed upper circuit layer 1 and lower circuit layer 2 respectively;

[0033] Step 5: Apply glue to both sides of the middle barrier layer 3 or to the surfaces of the upper circuit layer 1 and the lower circuit layer 2, avoiding the high-impedance carbon strips 15 when applying glue;

[0034] Step 6: Lay the upper circuit layer 1 and the lower circuit layer 2 on the upper and lower sides of the middle barrier layer 3 respectively. After finalization, trimming and testing are carried out before packaging.

Claims

1. An anti-ghosting keyboard circuit board, comprising an upper circuit layer (1), a lower circuit layer (2) and a middle partition layer (3), wherein the upper circuit layer is provided with an upper circuit (12), the lower circuit layer is provided with a lower circuit (22), the middle partition layer is fixedly clamped between the upper circuit layer and the lower circuit layer, and the middle partition layer is provided with a plurality of middle layer holes (31), characterized in that: The lower circuit on the lower circuit layer is provided with a plurality of lower conductive points (21) at intervals, and the upper circuit on the upper circuit layer is provided with a plurality of branch-shaped bypasses (13) at intervals. The end of each bypass is provided with an upper conductive point (11). The upper conductive point, the lower conductive point and the middle layer hole are arranged opposite to each other. Pressing the pressing point on the upper circuit layer corresponding to the upper conductive point can deform the corresponding bypass, thereby making the upper conductive point at the end of the bypass contact and conduct with the lower conductive point through the middle layer hole on the middle spacer layer, thereby forming an input signal.

2. The anti-ghosting keyboard circuit board according to claim 1, characterized in that: A plurality of bypasses on the upper circuit layer are arranged at intervals along the same straight line, and the roots of adjacent bypasses are connected in series via a U-shaped circuit (14).

3. The anti-ghosting keyboard circuit board according to claim 1, wherein: Each bypass is provided with a high-impedance carbon strip (15) of fixed length, and the high-impedance carbon strip is connected in series with the upper conductive point. An input signal current intensity detection module and a multi-key judgment module are provided in the computer system. The input signal current intensity detection module can detect the current intensity of the input signal formed by the contact between the upper conductive point and the lower conductive point. The input signal current intensity detection module can transmit the current intensity data to the multi-key judgment module. The multi-key judgment module can compare the current intensity detected by the input signal current intensity detection module with the pre-stored single-key pressing current intensity and judge whether it is a multi-key pressing.

4. The anti-ghosting keyboard circuit board according to claim 3, wherein: The high-impedance carbon strip is formed on the upper circuit on the surface of the upper circuit layer by printing high-impedance carbon paste.

5. The anti-ghosting keyboard circuit board according to claim 3, wherein: The high-impedance carbon strip ensures that the resistance of a single key loop formed by the contact between a single upper conductive point and a lower conductive point is 2500 ohms to 7000 ohms.

6. The anti-ghosting keyboard circuit board according to claim 1, characterized in that: The upper conductive dots and the lower conductive dots are both conductive silver dots formed by solidifying conductive silver paste.

7. The anti-ghosting keyboard circuit board according to claim 1, wherein: The upper circuit, bypass and upper conductive points are formed on the surface of the upper circuit layer by printing and drying, and the lower circuit and lower conductive points are formed on the surface of the lower circuit layer by printing and drying.

8. The anti-ghosting keyboard circuit board according to claim 1, wherein: The upper circuit layer and the lower circuit layer are made of flexible film materials, and the middle barrier layer is a sheet structure formed by sequentially pre-shrinking, striping, punching middle-layer holes and cutting a T-base material.

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