Touch panel and electronic device

Abstract

The present application proposes a touch panel installed in an electronic device receiving cavity, characterized in that it includes: a pressing layer for receiving a user's pressing operation; at least one sensing module disposed against the pressing layer; each sensing module includes a PCB with a FR4 glass fiber board substrate and a sensing layer, the PCB with a FR4 glass fiber board substrate includes a fixed end fixedly installed inside the receiving cavity, and a movable end movable relative to the receiving cavity, and the sensing layer is used to detect the deformation of the PCB with a FR4 glass fiber board substrate; the touch panel also includes a spacing layer, and the spacing layer is used to transmit the force of the pressing layer; on the connection line between the fixed end and the movable end of the PCB with a FR4 glass fiber board substrate, the sensing layer is located between the spacing layer and the fixed end. The touch panel has a low cost, and the PCB with a FR4 glass fiber board substrate serves as both a strain layer and a sensing module circuit routing, which simplifies the complexity of assembly and has the ability to realize multi-position touch and multi-level pressure detection.

Description

Technical Field

[0001] The present application belongs to the field of pressure sensing, and more specifically, relates to a touch panel and an electronic device. Background Art

[0002] In the field of touch technology, touch feedback modules are widely used in touch devices such as laptops, touch-screen phones, vehicle-mounted equipment, industrial control equipment, etc. because they can achieve touch feedback and pressure perception effects.

[0003] Different application fields have different performance requirements for touch devices. For example, laptop touchpads generally need to have position detection and pressure sensing, which are usually detected by different sensors. For pressure sensing, traditional touchpads often use a single-sided fixed structure. The closer to the fixed side, the greater the required pressure, and can only determine whether it is pressed, but cannot achieve richer interactive functions based on the pressure applied at a certain position.

[0004] Therefore, in order to solve the problem that the traditional notebook touchpad has a fixed pressing position due to the structural limitation and has no multi-level pressure detection, resulting in a single interactive function, the existing technical solution is like the Force Touch touchpad adopted by Apple, which sets a pressure sensor at each of the four corners of the touchpad, and executes the corresponding instructions according to the pressure detected by the pressure sensor, and can even simulate feedback vibration based on pressure sensing and linear motor. This type of solution realizes multi-area touch control. Specifically, a similar solution can be referred to in Figure 1, including a steel sheet 3, a spacer layer 4, a flexible circuit board 5, and a pressure sensing ink 6 arranged on the flexible circuit board. The pressure sensing ink 6 is arranged on the flexible circuit board 5, which is used to detect the deformation of the steel sheet 3 and output the detection signal to the external control circuit board 2 through the flexible circuit board 6.

[0005] Or a touch device as disclosed in Chinese patent CN202020246916.6, including a support beam with a free end and a fixed end, a sensor module detects the deformation of the support beam, and the sensor module includes a flexible circuit board bonded to the support beam as a base and a sensor welded on the flexible circuit board. However, this type of solution consists of more components and is more expensive; and generally requires the steel support beam and the flexible circuit board to be bonded by hot pressing, which increases the production process cost, and the hot pressing process is more complicated, generally requiring special jigs for positioning, and there are also problems of sensor defects caused after hot pressing.

[0006] Or there is the Free Touch touchpad used by Huawei, which completes full-area pressing of the touchpad by setting up 8 piezoelectric ceramic pressure sensors. The piezoelectric ceramic sensor obtains the pressure size by obtaining a brief voltage change through an instantaneous impact on the piezoelectric ceramic pressure sensor. Its production requires uniform piezoelectric ceramic parts, and it needs to be installed on a set structure through a special installation method. This approach greatly increases the cost of using the pressure sensor; and the uniformity of the trigger force of pressing at different positions is poor.

[0007] Therefore, the prior art may be unsuitable for multi-level pressure detection / touch due to structural limitations, resulting in weak touch panel interaction functions, or the touch panel using multi-position, multi-level pressure detection has high costs and poor consistency.

[0008] Based on this, in the field of touch panels, there is a need for a touch panel that can realize multi-position and multi-level pressure detection functions at a low cost, and each touch position can be set with a corresponding interactive function according to the force applied to the position. Summary of the invention

[0009] Based on this, the present application proposes a touch panel that can at least solve the problems existing in the prior art, comprising: a pressing layer for receiving a pressing operation of a user; at least one sensing module disposed against the pressing layer;

[0010] Each sensing module includes a strain layer and a sensing layer, wherein the strain layer is a PCB with a FR4 glass fiber board substrate, and the PCB with a FR4 glass fiber board substrate includes a fixed end fixedly installed inside the accommodating cavity, and a movable end movable relative to the accommodating cavity;

[0011] The sensing layer is located on one side of the PCB active end of the FR4 glass fiber board substrate facing the pressing layer, and the sensing layer detects the deformation of the PCB of the FR4 glass fiber board substrate;

[0012] The touch panel further comprises a spacer layer, the spacer layer is located on one side of the PCB active end of the FR4 glass fiber board substrate facing the pressing layer, and the spacer layer transmits the force of the pressing layer;

[0013] On the connection line between the PCB fixed end and the movable end of the FR4 glass fiber board substrate, the sensing layer is located between the spacing layer and the fixed end.

[0014] In this solution, the user presses the pressing layer, and the spacer layer between the pressing layer and the FR4 glass fiber board substrate PCB transfers pressure to the FR4 glass fiber board substrate PCB. Since the spacer layer is located at the active end of the FR4 glass fiber board substrate PCB and the FR4 glass fiber board substrate PCB is in the structure of a cantilever beam, the deformation of the FR4 glass fiber board substrate PCB near the spacer layer is large, and the sensing layer senses the deformation of the FR4 glass fiber board substrate PCB. It can be understood that the pressure pressed by the user is positively correlated with the deformation of the FR4 glass fiber board substrate PCB, so that the corresponding interactive functions can be graded according to the pressing pressure. In addition, since the FR4 glass fiber board substrate PCB as a component of the sensing module is in the structure of a cantilever beam, only one end of it needs to be fixed in the accommodating cavity of the electronic device to be installed to complete the pressure detection, so that multiple FR4 glass fiber board substrate PCB fixing positions are set in the accommodating cavity to achieve pressure detection of multiple touch positions. In addition, since a PCB with an FR4 glass fiber board substrate is used as a strain element, compared with a combination of materials such as steel sheets and flexible pressure sensors, the structure of using the sensing layer of the present application to detect the strain of a PCB with an FR4 glass fiber board substrate reduces the cost of the touch panel while meeting the basic conditions for stress detection.

[0015] Optionally, the thickness of the PCB of the FR4 glass fiber board substrate is less than or equal to 1.6 mm.

[0016] Optionally, the thickness of the PCB of the FR4 glass fiber board substrate is greater than or equal to 1.0 mm.

[0017] Optionally, the touch panel includes four sensing modules, which are respectively located at four corners of the pressing layer.

[0018] Optionally, the PCBs of the FR4 glass fiber board substrate of every two sensing modules located on the same side are connected.

[0019] Optionally, the FR4 glass fiber board substrate PCBs of all the sensor modules are connected.

[0020] Optionally, the sensing layer is a pressure-sensitive ink, and its resistance value changes with the deformation of the PCB of the FR4 glass fiber board substrate.

[0021] Optionally, a connector is provided on the PCB of the FR4 glass fiber board substrate, which is used to transmit the deformation signal of the PCB of the FR4 glass fiber board substrate detected by the sensing layer to an external control circuit board.

[0022] Optionally, the PCB with FR4 glass fiber board substrate is provided with at least one stress concentration groove penetrating through the thickness thereof, and the deformation of the PCB with FR4 glass fiber board substrate at the induction layer is concentrated in the stress concentration groove.

[0023] With respect to the touch panel for detecting the tensile deformation of the PCB of the FR4 glass fiber board substrate proposed in the first aspect, the touch panel for detecting the compressive deformation of the PCB of the FR4 glass fiber board substrate proposed in the second aspect is different from the touch panel of the first aspect in that, in this scheme, the spacer layer is arranged on the side surface of the PCB active end of the FR4 glass fiber board substrate facing the pressing layer, and the sensing layer is arranged on the other side surface of the PCB active end of the FR4 glass fiber board substrate facing away from the pressing layer. The sensing layer is used to detect the deformation of the PCB of the FR4 glass fiber board substrate, and the spacer layer is used to transfer the force of the pressing layer to the PCB of the FR4 glass fiber board substrate.

[0024] Furthermore, an electronic device with a touch function is provided, which includes the touch panel of the aforementioned embodiment and a receiving cavity for installing the touch panel.

[0025] Other aspects and features of the present application will become apparent to those of ordinary skill in the art after reading the following description of specific embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a touch panel in the prior art;

[0027] Figure 2 This is a schematic diagram of a touch panel according to an embodiment of the present application;

[0028] Figure 3 for Figure 2 Another schematic diagram of a touch panel implementation;

[0029] Figure 4 for Figure 2 Another schematic diagram of a touch panel implementation;

[0030] Figure 5 for Figure 2 Another schematic diagram of a touch panel implementation;

[0031] Figure 6 A schematic diagram of another touch panel implementation method of the present application;

[0032] Figure 7 for Figure 6 Another schematic diagram of a touch panel implementation;

[0033] Figure 8 To include Figure 2 A schematic diagram of an electronic device in which a touch panel is implemented;

[0034] Fig. 9 This is a comparison chart of parameters related to deformation of PCB, stainless steel and FR4 glass fiber board substrate based on public information;

[0035] Fig.10Schematic diagram of the structural model used to measure the deformation-related parameters of PCB and stainless steel on FR4 glass fiber board substrate;

[0036] Fig.11 This is a comparison chart of the parameters related to deformation of the PCB and stainless steel of the measured FR4 glass fiber board substrate;

[0037] Fig.12 It is a structural schematic diagram of Comparative Example 2;

[0038] Fig.13 It is a schematic diagram comparing the uniformity deviations of Example 1, Comparative Example 1 and Comparative Example 2;

[0039] Fig.14 Schematic diagram for comparing the consistency of Example 1, Example 2 and Comparative Example 1;

[0040] Fig.15 It is a schematic diagram for comparing the linearity of Example 1, Example 2 and Comparative Example 1.

[0041] Main component symbols

[0042] Electronic devices 1 Accommodation cavity 10 Trackpad 20 Pressing layer 201 Spacer 202 Sensing module 203 PCB / strain layer based on FR4 fiberglass board 2031 Sensing layer 2032 Fixed end 2041 Activity side 2042 Stress Concentration Groove 2043 Test Points 2044 Studs 2045 Control circuit board 205 DETAILED DESCRIPTION

[0043] In order to make the purpose, principle, technical solution and advantages of the invention more clear, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that, as described in the content of the present application, the specific embodiments described here are used to explain the present application and are not used to limit the present application.

[0044] It should be specially noted that, for the sake of simplicity in the drawings, some connections or positional relationships that can be determined based on the text or technical content of the specification have been partially omitted or not all position change diagrams have been drawn. If the specification does not explicitly state the omitted or undrawn position change diagrams, it cannot be regarded as a lack of description. For the sake of simplicity in the explanation, they will not be described one by one in the specific explanation, but will be described uniformly here.

[0045] It can be understood that the touch pad proposed in the present application is used to be installed on electronic devices, such as laptop computers, vehicle-mounted equipment, industrial control equipment, etc. For the installation of the touch pad, it is necessary to open a receiving cavity on the electronic device, and then fix the touch pad in the receiving cavity to realize pressure detection at a specific position.

[0046] See also Figures 2 to 5, is an embodiment of the touch panel 20 of the present application, comprising: a pressing layer 201, for receiving a user's pressing operation. It can be understood that the pressing layer 201 described in the present application refers to the part that receives user pressing, or it can also be called a covering layer, a touch panel, etc. in other prior arts. It should be noted that in some applications of the touch panel 20, the sensing of the pressing operation and the position detection of the moving operation are usually combined to identify the pressing position and the pressing force, so that the pressing layer 201 receives the user's pressing and moving operations, that is, the present application does not exclude the same pressing layer 201 from having the function of receiving the user's moving operation. The present application does not limit the material of the pressing layer 201, and organic glass PMMA (Polymethylmethacrylate) material can be used, or when the touch panel 20 is not required to have a position detection function, the pressing layer 201 can also be made of aluminum alloy.

[0047] And at least one sensing module 203 abutting against the pressing layer 201. In combination with the following description of the spacing layer 202, it should be noted that the term "abutting against" here does not mean that the sensing module 203 is in direct contact with the pressing layer 201, that is, it cannot be understood as "contacting", but the sensing module 203 is closely arranged near the pressing layer 201. Generally speaking, along the direction in which the user presses the pressing layer 201, there are the pressing layer 201 and the sensing module 203 in sequence, and the sensing module 203 and the pressing layer 201 are connected through the spacing layer 202.

[0048] It should be stated that Figure 2 The portion surrounded by the dotted frame is marked as the sensing module 203, and the sensing module 203 indicated by the dotted frame only includes the PCB 2031 of the FR4 glass fiber board substrate and the sensing layer 2032. In addition, since the strain layer is a PCB of the FR4 glass fiber board substrate, in order to avoid different markings for the same component, in all the drawings of the present application, the reference numeral 2031 represents both the PCB of the FR4 glass fiber board substrate and the strain layer.

[0049] Each sensing module 203 includes a strain layer and a sensing layer 2032, wherein the strain layer is a PCB 2031 with a FR4 glass fiber board substrate, and the PCB 2031 with a FR4 glass fiber board substrate includes a fixed end 2041 fixedly installed inside the accommodating cavity 10, and a movable end 2042 movable relative to the accommodating cavity 10; thus, the PCB 2031 with a FR4 glass fiber board substrate is a cantilever beam structure with one end fixed and the other end movable. Optionally, in order to make the movable end 2042 movable relative to the accommodating cavity 10, there is a certain distance between the movable end 2042 and the bottom of the accommodating cavity 10. In one embodiment, the fixed end 2041 is fixedly installed with the accommodating cavity 10 using a stud 2045, so that the surface of the PCB 2031 with a FR4 glass fiber board substrate is located and the bottom of the accommodating cavity 10 maintains a predetermined distance. In the direction from the fixed end 2041 of the FR4 glass fiber board substrate to the movable end 2042, under the action of the same force, generally speaking, the deformation of the PCB 2031 of the FR4 glass fiber board substrate at the force point close to the fixed end 2041 is more obvious. Of course, for ordinary technicians in this field, the length of the PCB 2031 of the FR4 glass fiber board substrate depends on the specific accommodation cavity 10 or the installation space, and the length is defined as the straight-line distance between the fixed end 2041 of the FR4 glass fiber board substrate and the movable end 2042 of the PCB, and thus the PCB 2031 of the FR4 glass fiber board substrate with different lengths all belong to the protection scope of this application.

[0050] The touch panel 20 further includes a spacer layer 202. In one embodiment, the sensing layer 2032 and the spacer layer 202 are spaced apart and arranged on the same side of the PCB active end 2042 of the FR4 glass fiber board substrate facing the pressing layer 201. It can be understood that although the sensing layer 2032 and the spacer layer 202 are located on the same side of the PCB 2031 of the FR4 glass fiber board substrate, more specifically, the two are located at different positions on the same side of the PCB 2031 of the FR4 glass fiber board substrate. For example, Figure 4 In the pressing direction shown, there is no overlap between the projections of the sensing layer 2032 and the spacing layer 202 , and the sensing layer 2032 is used to detect the deformation of the PCB 2031 of the FR4 glass fiber board substrate.

[0051] In combination with the above, it can be understood that the present application records that the sensing layer 2032 is located at the PCB active end 2042 of the FR4 glass fiber board substrate because under the same conditions, the deformation of the active end 2042 is obvious. Therefore, for some settings in which the sensing layer 2032 is not at or far away from the active end 2042, so that the deformation of the sensing layer 2032 detecting the strain layer should not be considered to be substantially different from the present application, but should be considered as an inferior implementation method relative to the preferred implementation method of the present application.

[0052] The spacer layer 202 is used to transfer the force of the pressing layer 201 to the PCB 2031 of the FR4 glass fiber board substrate. Here, the spacer layer 202 is located on the side of the PCB 2031 of the FR4 glass fiber board substrate facing the pressing layer 201. The spacer layer 202 plays the role of transferring the force on the pressing layer 201. It can be understood that the spacer layer 202 can be in direct contact with the pressing layer 201; or indirectly in contact, for example, other layers can be provided between the pressing layer 201 and the spacer layer 202. As for the sensing layer 2032, the present application does not require it to transfer the force. Therefore, in the present application, in order to satisfy that the spacer layer 202 is also in contact with the pressing layer 201, the height of the sensing layer 2032 is less than or equal to the height of the spacer layer 202. Of course, considering that the sensing layer 2032 is used to detect the deformation of the PCB 2031 of the FR4 glass fiber board substrate, preferably, the height of the sensing layer 2032 is less than the height of the spacer layer 202 to avoid the contact between the sensing layer 2032 and the pressing layer 201, which affects the detection effect. It should be noted that in the present application, the provision of the spacer layer 202 is necessary. Since the PCB 2031 of the FR4 glass fiber board substrate is a cantilever beam structure, in order to better transfer the pressure on the pressing layer 201 to the PCB 2031 of the FR4 glass fiber board substrate, the use of the spacer layer 202 can make the pressure more concentrated. More specifically, the pressure on the pressing layer 201 is more concentrated on a certain position of the PCB 2031 of the FR4 glass fiber board substrate. In combination with the above, preferably, the position is located at the active end 2042 or close to the active end 2042. In one embodiment, the spacer layer 202 can be a gasket. Specifically, from the perspective of manufacturing technology, one side of the gasket is fixed to the active end 2042 of the PCB 2031 of the FR4 glass fiber board substrate by hot pressing or gluing, and the other side is adhered to the pressing layer 201.

[0053] The relative positions of the spacer layer 202 and the sensing layer 2032 are described below. Figure 2 or Figure 6 In the embodiment, the spacer layer 202 and the sensing layer 2032 are located on the same surface of the PCB 2031 of the FR4 glass fiber board substrate facing the pressing layer 201, so that the force of the pressing layer 201 is transmitted to the PCB 2031 of the FR4 glass fiber board substrate, and the PCB 2031 of the FR4 glass fiber board substrate bends downward, so that relative to the neutral plane of the PCB 2031 of the FR4 glass fiber board substrate, the aforementioned same surface is located above the neutral plane, resulting in tensile deformation, that is, in this embodiment, the sensing layer 2032 detects the tensile deformation of the PCB 2031 of the FR4 glass fiber board substrate.

[0054] Optionally, in other embodiments, the spacer layer 202 and the sensing layer 2032 may be located on different surfaces of the PCB2031 of the FR4 glass fiber board substrate. Specifically, the spacer layer 202 must be arranged on one surface of the PCB2031 of the FR4 glass fiber board substrate facing the pressing layer 201, and the sensing layer 2032 is arranged on the other surface of the PCB2031 of the FR4 glass fiber board substrate facing away from the pressing layer 201, so that relative to the neutral plane of the PCB2031 of the FR4 glass fiber board substrate, the aforementioned other surface is located below the neutral plane, resulting in compression deformation, that is, the sensing layer 2032 in this embodiment detects the compression deformation of the PCB2031 of the FR4 glass fiber board substrate. In this embodiment, since the spacer layer 202 and the sensing layer 2032 are located on different surfaces, there is no need to consider the relative height between the spacer layer 202 and the sensing layer 2032, and the sensing layer 2032 is located between the spacer layer 202 and the fixed end 2041 on the line connecting the PCB fixed end 2041 and the movable end 2042 of the FR4 glass fiber board substrate. This is based on the consideration of the transmission force on the one hand and the material of the spacer layer 202 on the other hand. That is, for some embodiments in which the spacer layer 202 is used to cover the entire surface of the PCB 2031 of the FR4 glass fiber board substrate, and its substantial function is consistent with that of the present application, it should also fall within the protection scope of the present application.

[0055] It should be noted that some of the drawings of the present application illustrate embodiments in which the spacer layer 202 and the sensing layer 2032 are located on the same surface of the PCB 2031 of the FR4 glass fiber board substrate facing the pressing layer 201 .

[0056] On the line connecting the fixed end 2041 and the movable end 2042 of the PCB of the FR4 glass fiber board substrate, the sensing layer 2032 is located between the spacer layer 202 and the fixed end 2041. Generally speaking, the end of the movable end 2042 of the PCB of the FR4 glass fiber board substrate is located within the defined range of each edge of the pressing layer 201, so the spacer layer 202 that acts as a force transmission is arranged at the end of the movable end 2042, and on the surface of the PCB2031 of the FR4 glass fiber board substrate, the sensing layer 2032 is located between the spacer layer 202 and the fixed end 2041. It should be noted that in other embodiments, the shape of the PCB2031 of the FR4 glass fiber board substrate may not be as shown in FIG. Figure 1 The PCB 2031 of the FR4 glass fiber board substrate is not straight as shown in the embodiment, but is windingly extended from the fixed end 2041 to form the movable end 2042, so that the whole is S-shaped. Then the term "connecting line" should be understood as the connecting line between the fixed end 2041 and the movable end 2042 along the direction in which the PCB 2031 of the FR4 glass fiber board substrate extends, and should not be understood as a straight line connecting the fixed end 2041 and the movable end 2042.

[0057] In some embodiments, when the touch panel 20 of the present application is used to realize the touch function of a notebook, the touch panel 20 includes four sensing modules 203. Since the pressing layer 201 is generally a rectangular structure, such as Figure 2 As shown, the four sensing modules 203 are respectively arranged at the four corners of the pressing layer 201; compared with the traditional touch panel 20 in which only the left and right sides of the lower part are used for pressing detection, this embodiment can realize pressing detection at any position of the touch panel 20, realizing the design of multiple touch positions of the touch panel 20, and improving the richness of the interactive function design of the touch panel 20.

[0058] In order to reduce the requirements for assembly accuracy, when multiple sensing modules 203 are included, it can be considered to connect the PCB 2031 of the FR4 glass fiber board substrate of adjacent sensing modules 203. For example, for a touch panel 20 including four sensing modules 203, the PCB 2031 of the FR4 glass fiber board substrate of every two sensing modules 203 on the same side are connected. Figure 2 , which means that the PCB2031 of the FR4 fiberglass board substrate of the two sensing modules 203 located on the left are connected, and the PCB2031 of the FR4 fiberglass board substrate of the two sensing modules 203 located on the right are also connected. It should be understood that the term "connected" means that the PCB2031 of the FR4 fiberglass board substrate of each two sensing modules 203 located on the same side are not separated, but the PCB2031 of the FR4 fiberglass board substrate of each sensing module 203 is divided according to the PCB2031 of the FR4 fiberglass board substrate of an integral piece, and the part of the PCB2031 of the FR4 fiberglass board substrate that is not divided into the sensing module 203 is connected to the PCB2031 of the FR4 fiberglass board substrate of different sensing modules 203. This setting method is convenient for processing and can reduce the cutting process of the PCB2031 of the FR4 fiberglass board substrate. Figure 6 In the PCB2031 structure of the FR4 fiberglass board substrate shown, four sensing modules 203 correspond to an "H"-shaped PCB2031 of the FR4 fiberglass board substrate. More importantly, the portion of the PCB2031 of the FR4 fiberglass board substrate that is not included in the sensing module 203 can be used as the setting position of the connector (not shown). Of course, the present application does not limit the specific position of the connector. A person of ordinary skill in the art can set the connector as required to ensure that the output voltage of the sensing module 203 can be transmitted to the external control circuit board 205 through the connector, thereby reducing the arrangement of flying wires and simplifying the internal space. Furthermore, optionally, in other embodiments, the PCB2031 of the FR4 fiberglass board substrate of all the sensing modules 203 are connected, refer to Figure 6 and Figure 7 The embodiment shown.

[0059] For the sensing layer 2032, in some embodiments, the sensing layer 2032 is a pressure-sensitive ink, or more specifically, four resistors are formed by printing resistor ink, and the connection of the four resistors can refer to the bridge circuit. For example, in the case of using pressure-sensitive ink, the pressing layer 201 is subjected to force, which is transmitted to the PCB 2031 of the FR4 fiberglass board substrate through the spacer layer 202. The PCB 2031 of the FR4 fiberglass board substrate is deformed by the stress, so that the resistance value of the resistor located near the active end 2042, that is, the PCB 2031 of the FR4 fiberglass board substrate where the force is applied changes, and the bridge circuit outputs a voltage signal to the external control circuit board 205. As for the specific form of the bridge circuit, it can have a single bridge, half bridge or full bridge Wheatstone bridge structure, which is not specifically limited. For example, when the PCB2031 of the FR4 glass fiber board substrate is subjected to stress, the surface of the PCB2031 of the FR4 glass fiber board substrate where the sensing layer 2032 is located undergoes tensile deformation. The greater the deformation, the greater the voltage signal output by the sensing module 203. The control circuit board 205 performs at least analog-to-digital conversion and amplification on the voltage signal, and issues corresponding instructions based on the processed signal, for example, dividing the corresponding specific interactive functions according to the processed signal interval to achieve multi-level touch.

[0060] It should be noted that, from the perspective of structural division, in the above embodiment, the connection lines between the resistors are not part of the sensing layer 2032, and the connection lines are pre-arranged on the PCB 2031 of the FR4 glass fiber board substrate. Optionally, a conductor is set at the end point connecting different resistors, and the resistor ink is printed on the conductor to form the sensing layer 2032.

[0061] In order to concentrate the strain of the PCB2031 of the FR4 glass fiber board substrate at the sensing layer 2032, the PCB2031 of the FR4 glass fiber board substrate is provided with at least one stress concentration groove 2043 penetrating its thickness at the corresponding sensing layer 2032, so that the stress of the PCB2031 of the FR4 glass fiber board substrate with a cantilever beam structure is concentrated in the middle area of ​​the stress concentration groove 2043. It can be understood that the middle area is a solid area of ​​the PCB2031 of the FR4 glass fiber board substrate, so as to increase the deformation of the PCB2031 of the FR4 glass fiber board substrate in the middle area.

[0062] It should be noted that the present embodiment does not specifically limit the number and shape of the stress concentration grooves 2043. For example, two stress concentration grooves 2043 can be symmetrically arranged on the PCB 2031 of the FR4 glass fiber board substrate, and the stress concentration grooves 2043 can be arranged in a U shape, or in a V shape, a rectangle, or other slot forms that are prone to stress concentration, such as a half seam.

[0063] It can be understood that the sensing layer 2032 of the present application detects the strain of the PCB 2031 of the FR4 glass fiber board substrate. Since the PCB 2031 of the FR4 glass fiber board substrate can be used as a substrate for circuit routing, the voltage signal output by the sensing layer 2032 when detecting the deformation of the PCB 2031 of the FR4 glass fiber board substrate can be transmitted to the external control circuit board 205 through the circuit routing set on the PCB 2031 of the FR4 glass fiber board substrate through the connector. It should be noted that the "external" used to describe the relative position of the control circuit board 205 here is relative to the sensing module 203 as a whole. Specifically, the sensing module 203 in the present application only has the ability to sense the force transmitted by the pressing layer 201, so that the PCB 2031 of the FR4 glass fiber board substrate inside the sensing module 203 is deformed accordingly, thereby outputting a voltage signal. The voltage signal cannot be directly used as a driving instruction to make the electronic component respond, but needs to be further processed. Generally, the processing of the voltage signal is located on another circuit board, that is, the aforementioned external control circuit board 205. The control circuit board 205 is not a component of the pressure sensing module 203. The present application does not limit the position of the control circuit board 205 relative to other structures of the touch pad 20. For example, in one embodiment, the control circuit board 205 is attached to the pressing layer 201, that is, the spacer layer 202 is in indirect contact with the pressing layer 201. In the direction in which the pressing layer 201 is subjected to force, the control circuit board 205 supports the pressing layer 201, and the control circuit board 205 can detect the user's movement in the pressing layer 201.

[0064] It should be noted that the aforementioned external control circuit board 205 is not the same component as the PCB 2031 of the FR4 fiberglass board substrate in the sensing module 203 of the present application. The control circuit board 205 is arranged with more wiring and electronic components to process the sensor output signal. The PCB 2031 of the FR4 fiberglass board substrate of the present application is a cantilever beam structure, which is mainly used as a strain layer. The arrangement of too many electronic components will affect the deformation effect, especially when multiple touch positions need to be set to correspond to multiple sensing modules 203, the PCB 2031 of the FR4 fiberglass board substrate of the connected different sensing modules 203 will have inconsistent deformation, thereby affecting the user's touch effect.

[0065] In the present application, due to the characteristics of the PCB2031 of the FR4 glass fiber board substrate, the PCB2031 of the FR4 glass fiber board substrate not only acts as a strain layer to generate deformation to be detected by the sensing layer 2032, but also acts as a carrier of circuit routing, such as the connection line routing between the resistors constituting the sensing layer 2032 in some embodiments, and the routing of the voltage output by the sensing layer 2032 when detecting deformation. Compared with the existing touch panel 20 using materials such as steel sheets as the strain layer, the flexible circuit board is hot-pressed on the steel sheet, and the sensing element on the flexible circuit board detects the deformation of the steel sheet. From the perspective of cost, on the one hand, the structure of the sensing module 203 of the present application is simple and the cost of each component is low; on the other hand, the steel sheet and the flexible circuit board are generally bonded together by hot pressing, resulting in increased production costs; the manufacturing process of the sensing module 203 of the present application is simple. For example, the manufacturing of the sensing module 203 is completed by printing the sensing resistor on the PCB2031 of the FR4 glass fiber board substrate with the routing arranged. The sensing module 203 can complete the detection of pressure signals and the output of the sensing voltage, simplifying the production process and reducing costs.

[0066] In addition, the hot pressing process is more complicated and generally requires special jigs for positioning. Moreover, since the sensing elements often use pressure-sensitive inks, hot pressing can easily cause sensing element defects.

[0067] Furthermore, since the PCB2031 with a FR4 glass fiber board substrate serves as a carrier for circuit routing and connectors, when the touch panel 20 includes multiple sensing modules 203, the touch panel 20 of the present application has low difficulty in arranging the routing, does not require additional wiring space, and has a compact structure, which is conducive to application in scenarios with high requirements for layout space. In some embodiments, each sensing module 203 is also provided with a test point 2044, and the test points 2044 of different sensing modules 203 are located in the same area, such as the connection area of ​​the PCB2031 with a FR4 glass fiber board substrate of different sensing modules 203, which is conducive to testing the touch panel 20.

[0068] The term "PCB with FR4 fiberglass substrate" recorded in this application is explained in detail below. In the field of circuit design, PCB with FR4 fiberglass substrate (reference numeral 2031) generally refers to a printed circuit board (PCB) using FR4 fiberglass as the insulating layer substrate. Generally speaking, FR4 fiberglass refers to glass fiber that meets the FR4 grade, and more specifically, generally refers to a flame-resistant epoxy fiberglass board that meets the International Electrotechnical Commission EPGC202 standard. It should be noted that this application does not involve improvements to the components of PCB2031 with FR4 fiberglass substrate. The PCB2031 with FR4 fiberglass substrate described in this application refers to materials that meet the understanding of ordinary technicians in this field. Therefore, PCB2031 with FR4 fiberglass substrate is generally used as a carrier for circuit routing, electronic components, vias, etc., and further, for this application, the routing of the output signal of the sensing module 203 does not require an additional circuit layer or a flexible or printed circuit board design.

[0069] Generally speaking, for the selection of the strain layer, as recorded by the applicant in Chinese patent CN202021794525.4, "optionally, the elastic member 102 is made of metal, plastic, glass, or a composite material plate, which deforms when subjected to force, and can return to its initial state when the force disappears", that is, in order to achieve the multi-level touch function, the strain layer corresponding to the present application also needs to have a larger range of deformation, that is, a smaller elastic modulus, while avoiding plastic deformation within a predetermined force range.

[0070] Further, the following describes the conditions for the PCB2031 of the FR4 glass fiber board substrate to be used as a strain layer. Since 304 stainless steel has good processing performance and corrosion resistance, it is often used as a material for the strain layer in the touch field, that is, the steel sheet used in the above-mentioned prior art, the common grade is SUS304, but the steel sheet cannot be used as a carrier for circuit routing and vias, test points 2044, and connectors, and often needs to be used in conjunction with another flexible circuit board or printed circuit board as a circuit routing. See Fig. 9 , which is a comparison of deformation-related parameters of PCB2031 and SUS304 based on FR4 glass fiber board, compiled by the applicant based on public information. The parameter data of SUS304 refer to the sixth edition of the Mechanical Design Manual, Volume 1, Part 3, Chapter 1, Table 3-1-14 "Ferrous Metal Materials", national standard GB / T 20878 and other series of documents, and the parameter data of FR4 glass fiber board refer to IPC-4101 Rigid Multilayer Printed Circuit Board Base Material Requirements Specification and GB / T 5130 and other series of documents.

[0071] As can be seen from the figure, the elastic modulus of PCB2031 with FR4 fiberglass substrate is relatively small. Theoretically, under the same pressure conditions, the deformation of PCB2031 with FR4 fiberglass substrate is larger than that of SUS304, about seven times larger than that of SUS304.

[0072] Further, see Figure 10 to Figure 11 , the applicant adopts the same structural model, more specifically, a cantilever beam structure with one end fixed as used in the embodiment of the present application, and at the same time, when the same load (150g) acts on the force point shown in the figure, the deformation-related parameters of the cantilever beam structure using SUS304 material and PCB2031 material using FR4 glass fiber board substrate are compared. As shown in the figure, under the same aforementioned conditions, the strain of PCB2031 using FR4 glass fiber board substrate is about 5 times the strain of SUS304.

[0073] For clarification, elastic modulus refers to the mathematical description of the tendency of an object or substance to deform elastically when a force is applied to it. The elastic modulus affects the degree of deformation of the material. The larger the elastic modulus, the less likely the material is to deform.

[0074] Bending strength affects the failure limit of the material. Specifically, bending strength refers to the failure deformation such as fracture and yielding that will occur when the bending strength is exceeded.

[0075] Thus, according to Figures 9 to 11 The deformation-related parameters of PCB2031 with FR4 fiberglass substrate and SUS304 are compared. The bending strength of PCB2031 with FR4 fiberglass substrate is larger, it is not easy to break when receiving the force from the user's pressing, and the elastic modulus is smaller. Under the same boundary conditions, i.e., the same shape, size, load, and fixed conditions, the deformation of PCB2031 with FR4 fiberglass substrate is greater than that of SUS304. Therefore, the performance of PCB2031 with FR4 fiberglass substrate meets the conditions of being a strain layer, and is even better than SUS304.

[0076] The following is a comparison of parameters related to the touch panel sensing performance obtained by applying a PCB made of FR4 glass fiber board as a strain layer to the touch panel 20 structure proposed in this application. Specifically, Example 1 adopts Figure 2 The touch panel structure shown in the embodiment 2 also adopts Figure 2 The touch panel structure shown in the figure, the difference between Example 1 and Example 2 is that the PCB thickness of the FR4 glass fiber board substrate of Example 1 is 1.2mm, and the PCB thickness of the FR4 glass fiber board substrate of Example 2 is 1.6mm. For comparison, the applicant introduced two comparative examples of the prior art, wherein Comparative Example 1 adopts the method mentioned in the background technology section of this application as shown in FIG. Figure 1The structure of the touch panel shown in FIG. 1 is described in detail in the background technology section. Fig.12 The structure shown in the touch panel structure includes a control circuit board 2, a steel sheet 3, a spacer layer 4, a flexible circuit board 5, and a pressure sensor 6 located on the flexible circuit board 5, and the pressure sensor 6 detects the deformation of the steel sheet 4.

[0077] It should be noted that the above four schemes all adopt the form of setting four touch positions corresponding to the four corners of the pressing layer, that is, sensors are set at four positions accordingly. Regarding the above four schemes, the applicant compares them from the following dimensions such as uniformity, consistency, and linearity.

[0078] Uniformity test

[0079] 1. Test content: Use 5V voltage touch panel to power, draw several squares of equal area on the touch panel, apply 100g force on each square, it is recommended to use a dotting machine to test the ADC output of each sensor; the pressure head is recommended to use a stainless steel ball head with a size of φ8mm,

[0080] 2. Test results: See Fig.13 , Example 1 has good uniformity.

[0081] Conformance Testing

[0082] 1. Test content: Compare the deviation between the sensitivity of multiple sensors of the same model and the average sensitivity. The smaller the maximum deviation, the better the consistency.

[0083] 2. Test results: See Fig.14 The consistency of pressure detection at each touch position in Example 1 is improved due to Example 2 and Comparative Example 1, so that the pressing effect of each touch position of the user is more consistent, avoiding the situation where a large pressing force is required at a certain touch position and a small pressing force is required at another touch position.

[0084] Linearity test

[0085] 1. Test content: Take the ADC of 100g as the benchmark, make an ADC-force diagram through the origin, and get the theoretical ADC of 400g. Compare it with the actual measured ADC of 400g to get the difference between the actual value and the theoretical value; measure the linearity with the number of grams of deviation between the actual value and the theoretical value; the smaller the deviation, the better the linearity.

[0086] 2. Test results: See Fig.15 , the linearity performance of Example 1 and Example 2 is stable.

[0087] It is understandable that in the field of circuit design, PCB2031 with FR4 fiberglass substrate generally has fixed specifications. Most of SparkFun's products are 1.6mm thick, and some products also use other thicknesses, such as LilyPad uses 0.8mm. In combination with the above, in order to make the PCB2031 with FR4 fiberglass substrate used in this application as a strain layer have appropriate elastic deformation and resistance to plastic deformation, the thickness of PCB2031 with FR4 fiberglass substrate can also be customized. In fact, according to Figures 13 to 15 The test results shown in the figure show that, in general, when the thickness of the PCB 2031 of the FR4 glass fiber board substrate is relatively low, for example, less than or equal to 1.6 mm, or greater than or equal to 1.0 mm, the above dimensions of the touch panel 20 perform better. Therefore, the touch panel 20 proposed in the present application has lower cost and more convenient manufacturing process while having performance close to or even better than the prior art.

[0088] For further reference, Figure 8 , an electronic device 1 is proposed, specifically a laptop computer, with a touch function, which includes the touch panel 20 of the aforementioned embodiment and a receiving cavity 10 for installing the touch panel 20, more specifically, the fixed end 2041 of the PCB 2031 of the FR4 glass fiber board substrate is fixedly installed in the receiving cavity 10, and the fixed installation method can be a detachable installation method, for example, the fixed end 2041 of the PCB of the FR4 glass fiber board substrate is provided with a stud 2045. Optionally, in order to realize the detection of the touch position of the electronic device, in combination with the above, the electronic device also includes a control circuit board 205 disposed under the pressing layer 201, that is, between the spacer layer 202 and the pressing layer 201, to detect the user's position movement in the plane direction where the pressing layer 201 is located.

[0089] It should be noted that the present application discloses an implementation method of using a PCB with an FR4 glass fiber board substrate as a strain layer. Other technical solutions that use a simple replacement of the substrate based on the technical route, test standards, etc. of the present application, such as using a PCB with a ceramic substrate, a metal substrate, a paper substrate, or a composite substrate as the substrate as the strain layer, should also be regarded as disclosed by the present application.

[0090] It is worth noting that in the above embodiments, the modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0091] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A touch panel installed in a receiving cavity of an electronic device, characterized in that: include: The pressing layer is used to receive the user's pressing operation; At least one sensing module disposed against the pressing layer; Each sensing module includes a strain layer and a sensing layer, wherein the strain layer is a PCB with a FR4 glass fiber board substrate, and the PCB with a FR4 glass fiber board substrate includes a fixed end fixedly installed inside the accommodating cavity, and a movable end movable relative to the accommodating cavity; The touch panel further includes a spacing layer, the sensing layer and the spacing layer are spaced apart and arranged on the same side of the PCB active end of the FR4 glass fiber board substrate facing the pressing layer, along the direction in which the user presses the pressing layer, there is no overlapping part between the projections of the sensing layer and the spacing layer, the sensing layer detects the deformation of the PCB of the FR4 glass fiber board substrate, and the spacing layer transmits the force of the pressing layer to the PCB of the FR4 glass fiber board substrate; On the connection line between the PCB fixed end and the movable end of the FR4 glass fiber board substrate, the sensing layer is located between the spacing layer and the fixed end.

2. The touch panel according to claim 1, wherein: The thickness of the PCB of the FR4 glass fiber board substrate is greater than or equal to 1.0 mm.

3. The touch panel according to claim 1, wherein: The thickness of the PCB of the FR4 glass fiber board substrate is less than or equal to 1.6 mm.

4. The touch panel according to claim 2 or 3, characterized in that: The FR4 glass fiber board substrate PCB of each two sensing modules located on the same side is connected.

5. The touch panel according to claim 2 or 3, characterized in that: All sensor modules are connected to the FR4 glass fiber board substrate PCB.

6. The touch panel according to claim 5, wherein: The sensing layer is pressure sensing ink.

7. The touch panel according to claim 6, wherein: The PCB of the FR4 glass fiber board substrate is provided with a connector for transmitting the deformation signal of the PCB of the FR4 glass fiber board substrate detected by the sensing layer to an external control circuit board.

8. The touch panel according to claim 7, wherein: The PCB with FR4 glass fiber board substrate is provided with at least one stress concentration groove penetrating through the thickness thereof, and the deformation of the PCB with FR4 glass fiber board substrate at the induction layer is concentrated in the stress concentration groove.

9. A touch panel installed in an electronic device receiving cavity, characterized in that: include: The pressing layer is used to receive the user's pressing operation; At least one sensing module disposed against the pressing layer; Each sensing module includes a strain layer and a sensing layer, wherein the strain layer is a PCB with a FR4 glass fiber board substrate, and the PCB with a FR4 glass fiber board substrate includes a fixed end fixedly installed inside the accommodating cavity, and a movable end movable relative to the accommodating cavity; The touch panel further includes a spacer layer, the spacer layer is arranged on one side of the PCB active end of the FR4 glass fiber board substrate facing the pressing layer, the sensing layer is arranged on the other side of the PCB active end of the FR4 glass fiber board substrate facing away from the pressing layer, along the direction in which the user presses the pressing layer, there is no overlapping part between the projections of the sensing layer and the spacer layer, the sensing layer detects the deformation of the PCB of the FR4 glass fiber board substrate, and the spacer layer transmits the force of the pressing layer to the PCB of the FR4 glass fiber board substrate; On the connection line between the PCB fixed end and the movable end of the FR4 glass fiber board substrate, the sensing layer is located between the spacing layer and the fixed end.

10. An electronic device, characterized in that: It comprises the touch panel as claimed in claim 1 or claim 9, and a receiving cavity for fixing and installing the touch panel.

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