Thin film pressure detection module

Abstract

The invention discloses a thin film pressure detection module, comprising a covering layer, an insulating layer, a sensing layer, an MCU data processing module, and an FPC matrix wiring collector layer. The covering layer is an energized metal wiring layer. The MCU data processing module comprises a capacitance data collector. The capacitance data collector is responsible for collecting capacitance changes caused by changes in the distance between an energized metal shielding net and an FPC matrix wiring collector layer. The energized metal wiring layer and the sensing layer form a capacitor. The energized metal wiring layer is a capacitor A pole, and the sensing layer is a capacitor B pole. The invention has the beneficial effects of distinguishing the type of pressed object according to the pressure change amount collected by the collector, avoiding mistaken triggering of other buttons when the palm is in contact, and ensuring that the buttons are still valid when the palm is in contact. The capacitance of the energized metal mesh area is collected by monitoring multiple points, and the touch positioning position is accurately obtained according to the capacitance changes of different button areas.

Description

Technical Field

[0001] The present invention relates to the technical field of touch buttons, and in particular to a film pressure detection module. Background Art

[0002] Capacitive induction touch buttons can penetrate the outer shell of insulating materials for more than 8mm, accurately detect the effective touch of fingers, and ensure that the sensitivity, stability, reliability, etc. of the product will not change due to changes in environmental conditions or long-term use. It is also waterproof, has strong anti-interference capabilities, super protection, and super adaptability to temperature range. However, in actual application, fingertips often touch the control points, and palms fit on the metal panel of the card, resulting in false triggering of buttons and a series of unnecessary operations. At the same time, the touch position cannot be accurately obtained.

[0003] Based on the above problems, it is urgent to propose a thin film pressure detection module, which can distinguish the type of pressed object according to the pressure change collected by the collector, avoid accidentally triggering other buttons when the palm is in contact, and ensure that the buttons are still valid when the palm is in contact. By monitoring multiple points, the capacitance of the energized metal mesh area is collected, and the touch location is accurately obtained according to the capacitance changes in different button areas. Summary of the invention

[0004] The purpose of the present invention is to provide a thin film pressure detection module to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A thin film pressure detection module, the thin film pressure detection module includes a covering layer, an insulating layer, a sensing layer, an MCU data processing module and an FPC matrix wiring collector layer, the covering layer is an energized metal wiring layer, the insulating layer is located between the covering layer and the sensing layer, the MCU data processing module includes a capacitance data collector, the capacitance data collector is responsible for collecting capacitance changes caused by changes in the distance between the energized metal shielding net and the FPC matrix wiring collector layer, the energized metal wiring layer and the sensing layer form a capacitor, the energized metal wiring layer is the capacitor A pole, and the sensing layer is the capacitor B pole.

[0007] Furthermore, the energized metal wiring layer includes a*b areas, and the capacitance data collector uses a*b FPC copper foils, wherein each FPC copper foil collects the capacitance of its corresponding area, and locates the regional baseline of the touch button according to the regional difference of the capacitance. One FPC copper foil corresponds to one area, and in terms of data collection, the collection efficiency is improved, and the collected capacitance area corresponds to the position of the FPC copper foil.

[0008] Further, the values collected by the capacitance data collector include TKnBSA, TKnBSB, TKnBSC, TKd(n), and TKSd(n). TKnBSA is the capacitance value of the nth area collected by the collector at regular time intervals during collection. This may cause current instability during collection. Without interval sampling, data errors may occur. By taking samples at intervals, the current can be restored to stability, reducing data errors. At the same time, the interval time for each data collection is the same, facilitating data processing and analysis. It is the capacitance value of the nth area collected when the energized metal shielding net is energized in the positive direction. TKnBSB is the capacitance value of the nth area collected by the collector at regular time intervals when the energized metal shielding net is energized in the negative direction. The coding values of TKnBSA and TKnBSB are different. TKnBSC is the capacitance value of the nth area when the shielding is removed, where 0 < n < a*b. TKnBSA, TKnBSB, and TKnBSC are the no-button reference values for positioning the touch control button area. TKnBSA, TKnBSB, and TKnBSC can determine whether the shielding layer is working properly and generate a 0 reference at TKd(n). TKd(n) and TKSd(n) are the capacitance change amount and pressure change amount of the corresponding area caused by the change in the distance between the energized metal shielding net and the FPC matrix wiring collector layer, respectively.

[0009] Further, the thin-film pressure detection module can distinguish the types of pressed objects according to the pressure change amount TKSd(n) collected by the collector. The types of pressed objects are divided according to the pressure threshold. Different types of objects will generate different pressure change amounts when pressed. At this time, the types of pressed objects can be distinguished according to the corresponding interval where the pressure change amount is located, avoiding accidental triggering of other buttons when the palm is attached, and ensuring that the buttons are still effective when the palm is attached.

[0010] Further, the thin-film pressure detection module uses an energized metal shielding net, with the positive and negative electrodes running in parallel with a certain line width and line spacing. The positive and negative electrodes are powered in a cycle of swapping at a certain period, powered by a small current of the battery, and different wiring methods are used in different areas according to the number of touch matrices. The loop bending angle and parallel distance difference are adjusted. The wiring differences in different areas will result in different capacitance values in each area. According to the capacitance value differences in different areas, the touch position of the touch control button can be quickly located.

[0011] Further, the energized metal shielding net serves as one pole of the capacitor. By the slight pressure of touching, the distance between the energized metal shielding net and the collector is changed, thereby changing the capacitance value. At the same time, the touch control button position is located according to the different capacitance values obtained by the collector.

[0012] Furthermore, when the film pressure detection module is powered on in the forward direction, if no button is pressed, the capacitance value TKn of the corresponding area collected at this time is close to the current TKnBSA. If a button is pressed, TKd(n) is generated, and the baseline tends to the coding area where the relative touch button is located. At this time, the corresponding coding area is used to compensate TKnBSA to generate a D close to 0. base , use TKnBSA to obtain a reference close to 0. At this time, TKd(n) changes. According to TKd(n), the touch position is located. When the negative power is turned on, the comparison baseline TKnBSA is replaced by TKnBSB, where 0 <n<a*b。

[0013] Furthermore, the D base is the current collection count value when no button is pressed. This collection count value is the collection count value of the capacitance value formed between the capacitor A pole formed by the energized metal plate and the different capacitor B poles. In different energized phase time periods, D base The values ​​are close to TKnBSA, TKnBSB, and TKnBSC respectively. If you press with your finger, you need to use the baseline of the corresponding area to correct it to get a D close to the 0 baseline for a period of time. base TKn, through correction, can achieve more accurate touch position positioning. The baselines of different areas are also different. If pressed with an insulating object, this step of correction is not required.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: the type of pressed object can be distinguished according to the pressure change collected by the collector, avoiding the accidental triggering of other buttons when the palm is in contact, while ensuring that the buttons are still effective when the palm is in contact, and collecting the capacitance of the energized metal mesh area by monitoring multiple points, monitoring whether the shielding mesh is energized normally, and accurately obtaining the touch location according to the capacitance changes in different button areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 It is a schematic diagram of the device structure of the film pressure detection module of the present invention;

[0017] Figure 2 It is a schematic diagram of the steps of obtaining the reference code value of the film pressure detection module of the present invention;

[0018] Figure 3 It is a schematic diagram of the steps of determining the position of a touch key of the film pressure detection module of the present invention;

[0019] Figure 4 It is a schematic diagram of the steps of locating the position of the touch key by Tkd(n) of the thin film pressure detection module of the present invention;

[0020] Figure 5 This is a schematic diagram of the FPC matrix wiring collector layer of the thin film pressure detection module of the present invention;

[0021] Figure 6 This is a schematic diagram of the touch button partitioning of the film pressure detection module of the present invention;

[0022] Figure 7 It is the baseline code table collected by the film pressure detection module of the present invention in the collector;

[0023] Figure 8 It is a reference code table of the film pressure detection module of the present invention;

[0024] Fig. 9 It is a capacitance schematic diagram of the thin film pressure detection module of the present invention;

[0025] Fig.10 It is a schematic diagram of the finger pressing TK7 waveform of the thin film pressure detection module of the present invention;

[0026] Fig.11 It is a schematic diagram of the waveform of a gloved finger pressing TK7 of the thin film pressure detection module of the present invention.

[0027] Fig.12 It is a compression waveform series diagram of the film pressure detection module of the present invention;

[0028] Fig.13 This is the wiring and current diagram of TK4 and TK7 of the thin film pressure detection module of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-13 , the present invention provides a technical solution:

[0031] Film pressure detection module. The film pressure detection module includes a covering layer, an insulating layer, a sensing layer, an MCU data processing module, and an FPC matrix wiring collector layer. Among them, the covering layer is an energized metal wiring layer, the insulating layer is located between the covering layer and the sensing layer, the MCU data processing module includes a capacitance data collector, and the capacitance data collector is responsible for collecting the capacitance value change generated by the distance change between the energized metal shielding net and the FPC matrix wiring collector layer. The energized metal wiring layer and the sensing layer form a capacitor, the energized metal wiring layer is the A pole of the capacitor, and the sensing layer is the B pole of the capacitor.

[0032] As Figure 1 , 5 , and 6 show the device structure diagram, the FPC collection layer schematic diagram, and the touch button partition schematic diagram respectively. Taking the 3*4 matrix button as an example, the covering layer is an energized metal wiring layer, the capacitance data collector uses a 3*4 FPC copper foil, and the metal wiring layer is divided into 12 areas. The coding table is given by naming the partitions respectively. During different polarity energization cycles, the values collected by the capacitance data collector include TKnBSA, TKnBSB, TKnBSC, TKd(n), and TKSd(n). TKnBSA is the capacitance value of the nth area collected by the collector at a certain time interval when the energized metal shielding net is energized in the positive direction. TKnBSB is the capacitance value of the nth area collected by the collector at a certain time interval when the energized metal shielding net is energized in the negative direction. The coding values of TKnBSA and TKnBSB are different. TKnBSC is the capacitance value of the nth area when the shielding is removed, where 0 < n < a*b. TKnBSA, TKnBSB, and TKnBSC are the no-button reference values for positioning the touch button area. TKnBSA, TKnBSB, and TKnBSC can determine whether the shielding layer is working properly and generate a 0 reference at TKd(n). TKd(n) and TKSd(n) are the capacitance value change amount and pressure change amount of the corresponding area caused by the distance change between the energized metal shielding net and the FPC matrix wiring collector layer respectively.

[0033] The capacitance value change amount TKd(n) and pressure change amount caused by the distance change between the energized metal shielding net and the collector are TKSd(n). The film pressure detection module can distinguish the types of pressed objects according to the pressure change amount TKSd(n) collected by the collector. The types of pressed objects include sharp objects, fingers, palms, etc. The types of pressed objects are divided according to the pressure threshold.

[0034] As Fig.12As shown, when pressing the key on the B1 pole in different ways and with different pressures, the strokes generated on the A pole and the Bn pole of the metal shielding net are different, and the values ​​of different heights relative to the 0 reference are obtained. The waveform series on the far left is the data sequence obtained by clicking the touch point with a pencil tip with a force of 50g. It can be seen that the value obtained by pressing with a sharp object is the highest. Therefore, on this card, when using a sharp object to click on the energized metal net, the most accurate and sensitive click can be achieved, and a similar effect can be achieved with fingernails. The second and third waveform series from the left are the data sequences obtained by pressing with a force of 50g with fingers wearing thick plush gloves and without thick plush gloves, respectively. It can be seen from the figure that the values ​​are relatively small relative to sharp objects. Similarly, whether or not to wear gloves has almost no effect on the obtained data sequence, and the values ​​of the two are close, so this can be used as the judgment threshold. The waveform series on the far right is the data sequence obtained when the hand grasps the pen and sticks it to the surface. In actual applications, there are often situations where the fingertips accidentally touch the touch point and the palm sticks to the metal panel of the card. The use of pressure TKSd judgment can correctly handle the response of the touch key.

[0035] like Fig. 9 As shown in the figure, when an object is pressed, the small pressure generated when pressing is used to judge this type of key. According to the capacitance formula C = εS / d, when pressed, the distance between the energized metal mesh and the collection layer will change, thereby changing the capacitance. The greater the pressure, the greater the capacitance change. The energized metal mesh is used as one pole of the capacitor. The pressing area S is a constant within a fixed time. When the distance d is reduced, the capacitance increases rapidly. At this time, the collected value is not related to the metal wiring area, but is positively correlated with the distance changed between the energized metal mesh and the collection layer. The acceleration of TKd(n) increases with the pressing speed. The thickness of the insulating layer of the FPC used is only 0.08mm. Calculated by a 70mm wide energized metal shielding mesh PCB, the curvature is less than 0.1%. The energized metal shielding mesh is formed in a small shape. The thickness of the metal layer determines that the stroke of the finger pressing will not be large, but the stroke of 0.08mm is enough to collect data. The pressure is 50g as a light press and 200g as a heavy press. When there is no pressure, the gap between the energized metal shielding mesh and the sensing layer is 0.08mm. At this time, the 0 reference D is corrected by TKnBSA / B base .

[0036] like Fig. 9 As shown in the figure, in different power-on time periods, the MCU data processing module simultaneously collects the count values ​​of all capacitors A-B1, A-B2, and A-B3 to obtain the current value RAWDATA A-B1 、RAWDATA A-B2 、RAWDATA A-B3 , and then take the value RAWDATA again after a period of time A-B1 、RAWDATAA-B2 、RAWDATA A-B3 , the weighted average of the two values ​​is used to obtain D base TK A-B1 , D base TK A-B2 , D base TK A-B3 When no key is pressed, this value is stable and close to the base value of the same phase. Therefore, the value when no key is pressed is not used as the judgment value. Therefore, the base value of the same phase is corrected to 0, which is called 0 reference. Fig. 9 In the figure, EL1 and EL2 are energized electrodes, EL1 is a positive group, and EL2 is a negative group. When a key is pressed, a key is pressed at the position corresponding to the capacitor B1 pole in the figure. At this time, a tiny formation is generated between the capacitor A pole and the capacitor B1 pole, and the distance d will be smaller than the value when it is not pressed. According to the formula C=εS / d, the capacitance value at the corresponding position will increase rapidly, so the collected value TKd(B1) rises rapidly relative to the 0 reference.

[0037] The thin film pressure detection module uses an electrified metal shielding net, with positive and negative electrodes running in parallel with a certain line width and line spacing. The positive and negative electrodes are switched in a certain cycle and powered by a small current from a battery. Different wiring methods are used in different areas according to the number of touch matrices to adjust the cycle bending angle and parallel distance differences, such as Fig.13 As shown in the figure, the wiring and current diagrams of TK4 and TK7 are shown. The wiring differences can be clearly seen. When the power is forwarded, if no key is pressed, the capacitance value TKn collected in the corresponding area is close to the current TKnBSA. If a key is pressed, TKd(n) is generated, and the baseline tends to the coding area where the relative touch key is located. At this time, the corresponding coding area is used to compensate TKnBSA, generating a D close to 0. base If an object is pressed, the baseline approaches TKnBSA. Use TKnBSA to obtain a baseline close to 0. At this time, TKd(n) changes. The touch position is located according to TKd(n). Take TK7 as an example. When TK7 is pressed with a force of about 50g, the following is generated: Fig.10 The superimposed waveform shown in the figure is obtained by subtracting the current TKd(n) from the baseline 0X0746 of TK7. Fig.11 The waveform based on 0 reference shown in , when pressed with the same force using a gloved finger, the baseline at this time is close to TKnBSA (0X2750), so using TKnBSA compensation, the same can be obtained as Fig.11The TKd(n) waveform shown makes it possible for the difference in baselines not to interfere with the judgment of the key. When the power is turned on in the negative direction, the steps are the same as above, but the comparison baseline is TKnBSB. When the shield is released, the key is invalid and no calculation is performed. If the position of the touch key needs to be obtained, it is processed in the same way as a normal touch key.

[0038] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Thin film pressure detection module, characterized in that: The thin-film pressure detection module includes a covering layer, an insulating layer, a sensing layer, an MCU data processing module, and an FPC matrix wiring collector layer. The covering layer is an energized metal wiring layer. The insulating layer is located between the covering layer and the sensing layer. The MCU data processing module includes a capacitance data collector. The capacitance data collector is responsible for collecting the capacitance value changes generated by the distance change between the energized metal shielding net and the FPC matrix wiring collector layer. The energized metal wiring layer and the sensing layer form a capacitor. The energized metal wiring layer is the A pole of the capacitor, and the sensing layer is the B pole of the capacitor; The energized metal wiring layer includes a*b regions. The capacitance data collector uses an FPC copper foil of a*b. Each FPC copper foil collects the capacitance value of its corresponding region, and at the same time locates the regional baseline of the touch key according to the regional difference of the capacitance value; The values collected by the capacitance data collector include TKnBSA, TKnBSB, TKnBSC, TKd(n), and TKSd(n). TKnBSA is the capacitance value of the nth region collected by the collector when the energized metal shielding net is energized positively at a certain time interval. TKnBSB is the capacitance value of the nth region collected by the collector when the energized metal shielding net is energized negatively at a certain time interval. The encoded values of TKnBSA and TKnBSB are different. TKnBSC is the capacitance value of the nth region when the shielding is removed, where 0 < n < a*b. TKnBSA, TKnBSB, and TKnBSC are the no-key reference values for positioning the touch key area. TKnBSA, TKnBSB, and TKnBSC are used to judge whether the shielding layer is working properly and generate a 0 reference at TKd(n). TKd(n) and TKSd(n) are the capacitance change amount and pressure change amount of the corresponding region caused by the distance change between the energized metal shielding net and the FPC matrix wiring collector layer respectively.

2. A thin film pressure detection module according to claim 1, characterized in that: The thin-film pressure detection module distinguishes the types of pressed objects according to the pressure change amount TKSd(n) collected by the collector. The types of pressed objects are divided according to the pressure threshold.

3. A thin film pressure detection module according to claim 1, characterized in that: The thin-film pressure detection module uses an energized metal shielding net, and the positive and negative electrodes are wired side by side with a certain line width and line spacing. The positive and negative electrodes are powered by swapping at a certain cycle, powered by a small current of the battery, and different wiring methods are adopted in different regions according to the number of touch matrices to adjust the cyclic bending angle and parallel distance difference.

4. A thin film pressure detection module according to claim 1, characterized in that: The energized metal shielding net serves as one pole of the capacitor. Through the tiny pressure of touch, the distance between the energized metal shielding net and the collector is changed, thereby changing the capacitance value. At the same time, the position of the touch key is located according to the different capacitance values obtained by the collector.

5. A thin film pressure detection module according to claim 1, characterized in that: When the film pressure detection module is powered on in the forward direction, if no button is pressed, the capacitance value TKn of the corresponding area collected at this time is close to the current TKnBSA. If a button is pressed, TKd(n) is generated, and the baseline tends to the coding area where the relative touch button is located. At this time, the corresponding coding area is used to compensate TKnBSA to generate a D close to 0. base , use TKnBSA to obtain a reference close to 0. At this time, TKd(n) changes. According to TKd(n), the touch position is located. When the negative power is turned on, the comparison baseline TKnBSA is replaced by TKnBSB, where 0 <n<a*b。 6. A thin film pressure detection module according to claim 5, characterized in that: The D base is the current collection count value when no button is pressed. This collection count value is the collection count value of the capacitance value formed between the capacitor A pole formed by the energized metal plate and the different capacitor B poles. In different energized phase time periods, D base The values ​​are close to TKnBSA, TKnBSB, and TKnBSC respectively. If you press with your finger, you need to use the baseline of the corresponding area to correct it to get a D close to 0 baseline for a period of time. base TKn, where the baselines of different areas are also different. If pressed with an insulating object, this step of correction is not required.

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