Wearing detection flexible circuit board and wearable device

Abstract

The embodiment of the invention discloses a wearing detection flexible circuit board and wearable equipment, and the wearing detection flexible circuit board comprises a detection channel layer, a reference channel layer, a grounding layer and a heat dissipation layer which are sequentially stacked, and a first insulating medium layer is arranged between the detection channel layer and the reference channel layer. And a second insulating medium layer is arranged between the reference channel layer and the grounding layer. According to the wearing detection flexible circuit board, the grounding layer is arranged, so that the influence on the wearing detection temperature coefficient when the temperature of the main control board changes can be reduced, and the wearing detection stability is improved.

Description

Technical Field

[0001] This invention relates to the field of wear detection technology, and more specifically, to a wear detection flexible circuit board and wearable device. Background Technology

[0002] With the development of smart glasses technology, people are increasingly demanding stylish, lightweight, and comfortable glasses. To make the temples as thin as possible, the relatively large main control board is typically placed at the rear of the temples, while the wear detection area is positioned near the ear. This results in the heat-generating area of ​​the main control board being too close to the wear detection area. Furthermore, since current wear detection methods generally use flexible circuit boards with both a detection channel layer and a reference channel layer, graphite sheets are typically used to cover the heat-generating area of ​​the main control board and the wear detection area to achieve temperature uniformity for both the main control board and the flexible circuit board, thus reducing the impact of the main control board's temperature on the flexible circuit board.

[0003] However, since the graphite sheet itself is a conductor and is in a suspended and ungrounded state, placing it directly next to the flexible circuit board will interfere with the electric field. This causes the wear detection temperature coefficient between the detection channel layer and the reference channel layer to become unstable due to the metal near the main control board in high and low temperature environments, ultimately leading to wear detection failure. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a flexible circuit board for wear detection and a wearable device, which can reduce the impact of main control board temperature changes on the wear detection temperature coefficient and improve the stability of wear detection.

[0005] In a first aspect, embodiments of the present invention provide a wearable detection flexible circuit board, the flexible circuit board comprising a detection channel layer, a reference channel layer, a ground layer and a heat dissipation layer stacked sequentially, wherein a first insulating dielectric layer is disposed between the detection channel layer and the reference channel layer, and a second insulating dielectric layer is disposed between the reference channel layer and the ground layer.

[0006] Optionally, the flexible circuit board further includes a shielding layer stacked between the reference channel layer and the ground layer, a third insulating dielectric layer disposed between the shielding layer and the ground layer, and a second insulating dielectric layer disposed between the reference channel layer and the shielding layer.

[0007] Optionally, the flexible circuit board further includes an adhesive backing layer, through which the grounding layer is fixed to the heat dissipation layer.

[0008] Optionally, the circumferential edge size of the detection channel layer and the circumferential edge size of the reference channel layer are the same, and the circumferential edge size of the ground layer is at least a first predetermined size larger than the circumferential edge size of the detection channel layer.

[0009] Optionally, the circumferential edge size of the detection channel layer, the circumferential edge size of the shielding layer, and the circumferential edge size of the grounding layer increase sequentially, and the circumferential edge size of the shielding layer is smaller than the circumferential edge size of the grounding layer by a second predetermined size.

[0010] Optionally, the grounding layer and the heat dissipation layer are copper-clad graphite sheets.

[0011] Optionally, the heat dissipation layer is a graphite sheet.

[0012] Optionally, the detection channel layer includes a plurality of spaced metal contacts, and the reference channel layer includes a plurality of spaced metal contacts.

[0013] In a second aspect, embodiments of the present invention provide a wearable device, the wearable device comprising: Equipment body; The main control board is installed inside the device body; The flexible circuit board as described in the first aspect is installed inside the device body, with the detection channel layer located on the side of the device body closer to the human body, and one side of the heat dissipation layer extending to cover the main control board. The flexible circuit board is electrically connected to the main control board.

[0014] Optionally, the heat dissipation layer is connected to the main control board via an adhesive layer.

[0015] Optionally, the wearable device further includes a detection chip integrated on the main control board, the detection chip being electrically connected to both the main control board and the flexible circuit board.

[0016] This invention provides a wearability detection flexible circuit board and a wearable device. The wearability detection flexible circuit board includes a detection channel layer, a reference channel layer, a ground layer, and a heat dissipation layer stacked sequentially. A first insulating dielectric layer is disposed between the detection channel layer and the reference channel layer, and a second insulating dielectric layer is disposed between the reference channel layer and the ground layer. By incorporating a ground layer, this wearability detection flexible circuit board can reduce the impact of main control board temperature changes on the wearability detection temperature coefficient, thereby improving the stability of wearability detection. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram of the structure of the wear detection flexible circuit board according to the first embodiment of the present invention; Figure 2 This is another structural schematic diagram of the grounding layer according to the first embodiment of the present invention; Figure 3This is a schematic diagram of the structure of the wear detection flexible circuit board according to the second embodiment of the present invention; Figure 4 This is another structural schematic diagram of the grounding layer and shielding layer according to the second embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the wear detection flexible circuit board according to the third embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the wearable device according to the first embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a wearable device according to the second embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of a wearable device according to the third embodiment of the present invention.

[0018] Figure label: 100-Flexible circuit board; 1-Detection channel layer; 2-Reference channel layer; 3-Grounding layer; 4-Heat dissipation layer; 5-First insulating dielectric layer; 6-Second insulating dielectric layer; 7-Shielding layer; 8-Third insulating dielectric layer; 9-Adhesive backing layer; 200-Wearable device; 201-Device body; 202-Main control board; 203-Adhesive layer. Detailed Implementation

[0019] The present application is described below based on embodiments, but it is not limited to these embodiments. In the detailed description of the present application below, certain specific details are described in detail. Those skilled in the art can fully understand the present application without these details. To avoid obscuring the substance of the present application, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0020] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0021] Unless the context explicitly requires it, words such as "including" or "contains" throughout the application should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to".

[0022] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0023] This application provides a flexible circuit board for wear detection, applied in wearable devices, to detect the wearing status of the wearable device. By incorporating a ground layer, this flexible circuit board can reduce the impact of main board temperature changes on the wear detection temperature coefficient, thereby improving the stability of wear detection. The wearable device can be a smart headset, smart glasses, smartwatch, etc.

[0024] In the first embodiment, the flexible circuit board 100 includes a detection channel layer 1, a reference channel layer 2, a ground layer 3, and a heat dissipation layer 4 stacked sequentially. A first insulating dielectric layer 5 is disposed between the detection channel layer 1 and the reference channel layer 2, and a second insulating dielectric layer 6 is disposed between the reference channel layer 2 and the ground layer 3. Figure 1 As shown.

[0025] The detection channel layer 1 is used to directly sense whether the user is wearing a wearable device, typically by detecting changes in a physical quantity (such as capacitance, impedance, infrared reflection, temperature, etc.). In this embodiment, the detection channel layer 1 determines whether the user is wearing a wearable device by detecting changes in capacitance.

[0026] The detection channel layer 1 can be formed by a single layer of filled metal, or by multiple spaced metal contacts, each of which can serve as a detection electrode. When a user (such as an ear or skin) approaches or touches these detection electrodes, the local electric field changes, causing a change in capacitance. The metal contacts can be formed using conductive materials with good conductivity, processability, and stability, such as copper, conductive ink, and indium tin oxide.

[0027] Reference channel layer 2 does not directly contact the human body and is not sensitive to the wearing status, but it is subject to the same environmental interference (such as temperature) as detection channel layer 1. Reference channel layer 2 is used to provide a stable reference signal to eliminate common-mode interference (such as changes in ambient temperature and humidity, power fluctuations, electromagnetic interference, etc.), thereby improving detection accuracy and reliability.

[0028] The reference channel layer 2 can be formed by a single layer of metal or by multiple spaced metal contacts. Each metal contact can serve as a reference electrode, sensing the same environmental interference (such as temperature and humidity) as the detection electrode. Since the reference electrode is unaffected by the wearer's movements, it provides a reference signal that can be used for differential or calibration purposes. Specifically, the signal from the detection channel layer 1 is compared with the signal from the reference channel layer 2 (e.g., by performing differential calculations) to eliminate common-mode noise and retain the signal changes truly caused by wear, thereby improving detection accuracy and reliability. The metal contacts of the reference channel layer 2 can be made of the same material as the metal contacts of the detection channel layer 1.

[0029] A first insulating dielectric layer 5 is disposed between the detection channel layer 1 and the reference channel layer 2. The first insulating dielectric layer 5 serves to achieve electrical isolation and functional differentiation between the detection channel layer 1 and the reference channel layer 2, preventing short circuits or leakage between the detection electrode and the reference electrode, and ensuring independent signals for each. The first insulating dielectric layer 5 can be formed from a polymer substrate (such as polyimide, FR-4), possessing good insulation properties. The thickness of the first insulating dielectric layer 5 is typically 25-100 μm. It should be noted that the multiple spaced metal contacts in each layer can be filled with an insulating dielectric or physically separated (air or solder resist material) to achieve electrical isolation and functional differentiation between the metal contacts.

[0030] In other implementations, the detection channel layer 1 and the reference channel layer 2 can be laid out on the same layer and physically separated from each other. They can be insulated and isolated in the middle by air or solder resist material (such as solder resist ink), and their surfaces can be insulated and isolated by a cover film.

[0031] Ground layer 3 is located on the side of reference channel layer 2 away from detection channel layer 1. Ground layer 3 is used to shield the effects of parasitic capacitance, temperature, and interference from non-detection areas below, and to resolve the influence of the main control board's heating temperature on the temperature coefficient of the reference signal in the reference channel layer. This ensures that the temperatures of the detection channel layer and the reference channel layer are consistent, improving the accuracy of wear detection. The ground layer 3 can be made of copper, copper foil, etc., which have high electrical and thermal conductivity and are easy to etch.

[0032] It should be noted that the detection channel layer 1, reference channel layer 2, and ground layer 3 can be solid copper, grid copper, or strip copper.

[0033] A second insulating dielectric layer 6 is disposed between the reference channel layer 2 and the ground layer 3. The second insulating dielectric layer 6 separates the reference channel layer 2 from the ground layer 3 and prevents external electric fields from penetrating. The second insulating dielectric layer 6 maintains the high impedance of the reference channel layer 2 and, together with the ground layer, forms electromagnetic shielding, blocking the coupling of human body signals. The material of the second insulating dielectric layer 6 can be polyimide, FR-4, solder resist ink, epoxy resin, etc., possessing good insulation properties.

[0034] Preferably, the circumferential edge dimensions of the detection channel layer 1 and the reference channel layer 2 are the same, meaning that the detection channel layer 1 and the reference channel layer 2 completely overlap at their top edges when viewed from above. The circumferential edge dimension of the ground layer 3 is at least a first predetermined dimension larger than both the circumferential edge dimensions of the detection channel layer 1 and the reference channel layer 2. This first predetermined dimension needs to be set according to actual requirements. In this embodiment, the first predetermined dimension can be set to 0.2 mm. The setting of the circumferential edge dimension of the ground layer 3 can optimize the electric field distribution, making the electric field lines more concentrated and pointing towards the detection direction, effectively reducing the interference of other components or objects on the detection signal, reducing parasitic capacitance changes, and improving long-term stability.

[0035] In other ways, such as Figure 2 As shown, a lateral grounding layer 3 is sequentially arranged around the circumferential edge regions of the detection channel layer 1 and the reference channel layer 2. The lateral grounding layer 3 and the bottom grounding layer 3 are connected via electroplated vias to ensure electrical continuity. This structure allows the entire grounding layer 3 to form a three-dimensional shielding effect for the detection channel layer 1 and the reference channel layer 2, blocking lateral electric field leakage, changing the direction of the edge electric field lines, making the electric field lines more concentrated, enhancing anti-interference capabilities, and helping to maintain the stability of capacitance detection.

[0036] A heat dissipation layer 4 is disposed below the grounding layer 3 and extends to the main control board on one side. Specifically, the heat dissipation layer 4 extends to the heat-generating area of ​​the main control board. That is, the heat dissipation layer 4 covers both the main control board area and the wear detection area. The heat dissipation layer 4 is used to evenly heat the main control board area and the wear detection area, preventing the local temperature of the main control board from becoming too high and causing user discomfort. The heat dissipation layer 4 is a graphite sheet.

[0037] In this design, an adhesive layer 9 is provided on the side of the grounding layer 3 furthest from the detection channel layer 1, and the grounding layer 3 is fixed to the heat dissipation layer 4 via the adhesive layer 9. The adhesive layer 9 can be made of rubber, silicone, or other materials. The assembly of the grounding layer 3 and the heat dissipation layer 4 via the adhesive layer 9 is simple, facilitates production, and improves production efficiency.

[0038] After the flexible circuit board for wear detection is installed inside the wearable device, the detection channel layer 1 is positioned close to the human body area so that it can detect changes such as capacitance values ​​when in contact with or near the user's skin. The heat dissipation layer is used to evenly heat the flexible circuit board and the main control board, preventing localized high temperatures from causing discomfort to the user during wear. The grounding layer, located between the heat dissipation layer and the reference channel layer, reduces the impact of main control board temperature changes on the wear detection temperature coefficient, improving the stability of wear detection. In actual operation, when the value of the detection channel layer is subtracted from the reference channel layer's baseline value, if the difference is greater than a certain threshold, the wearable device is considered to be worn; if the difference is less than a certain threshold, the wearable device is considered not to be worn.

[0039] In the second embodiment, the flexible circuit board 100 further includes a shielding layer 7 stacked between the reference channel layer 2 and the ground layer 3, a second insulating dielectric layer 6 disposed between the reference channel layer 2 and the shielding layer 7, and a third insulating dielectric layer 8 disposed between the shielding layer 7 and the ground layer 3, such as... Figure 3 As shown.

[0040] The shielding layer 7 is used to suppress electromagnetic interference, thereby ensuring a high signal-to-noise ratio and reliability of the wear detection signal; at the same time, the shielding layer 7 can prevent mutual coupling between the sensing electrodes, control the direction of the induced electric field, and improve the sensitivity of wear detection. The material of the shielding layer 7 can be copper, copper foil, conductive silver paste, etc.

[0041] The second insulating dielectric layer 6 separates the reference channel layer 2 from the shielding layer 7, while preventing external electric fields from penetrating. The material of the second insulating dielectric layer 6 can be polyimide, FR-4, solder resist ink, epoxy resin, etc., and has good insulation properties.

[0042] Preferably, the circumferential edge dimensions of the detection channel layer 1 and the reference channel layer 2 are the same, meaning that the detection channel layer 1 and the reference channel layer 2 completely overlap at their top edges when viewed from above. The circumferential edge dimension of the ground layer 3 is at least a first predetermined dimension larger than both the circumferential edge dimensions of the detection channel layer 1 and the reference channel layer 2; this first predetermined dimension needs to be set according to actual requirements. The circumferential edge dimension of the shielding layer 7 is a second predetermined dimension smaller than the circumferential edge dimension of the ground layer; this second predetermined dimension also needs to be set according to actual requirements. In other words, the circumferential edge dimensions of the detection channel layer 1, the shielding layer 7, and the ground layer 3 increase sequentially. In this embodiment, the first predetermined dimension can be set to 0.2 mm, and the second predetermined dimension can be set to 0.1 mm.

[0043] The setting of the circumferential edge dimensions of the grounding layer 3 and the shielding layer 7 can optimize the electric field distribution, make the electric field lines more concentrated and point towards the detection direction, effectively reduce the interference of other components or objects on the detection signal, reduce parasitic capacitance changes and improve long-term stability.

[0044] In other ways, such as Figure 4 As shown, a lateral shielding layer 7 and a lateral grounding layer 3 are sequentially arranged around the circumferential edge regions of the detection channel layer 1 and the reference channel layer 2, respectively. A lateral grounding layer 3 is also arranged around the circumferential edge region of the shielding layer 7. The lateral shielding layer 7 and the bottom shielding layer 7 are connected via electroplated vias, and the lateral grounding layer 3 and the bottom grounding layer 3 are also connected via electroplated vias, ensuring electrical continuity. This structure allows the entire shielding layer 7 and grounding layer 3 to form a three-dimensional shielding effect for the detection channel layer 1 and the reference channel layer 2, blocking lateral electric field leakage, changing the direction of the edge electric field lines, making the electric field lines more concentrated, enhancing anti-interference capabilities, and helping to maintain the stability of capacitance detection.

[0045] In the third embodiment, the material of the heat dissipation layer 4 can be replaced by a copper-clad graphite sheet. When the material of the heat dissipation layer 4 is a copper-clad graphite sheet, the copper layer of the copper-clad graphite sheet can serve as the grounding layer 3, such as... Figure 5 As shown. That is, in the first embodiment, the grounding layer 3 and the heat dissipation layer 4 can be formed of copper-clad graphite sheets. This wearable detection flexible circuit board has a simple structure and low cost.

[0046] like Figure 6 , Figure 7 and Figure 8 As shown, this application embodiment provides a wearable device, the wearable device 200 including a device body 201, a main control board 202, and as shown in the figure. Figures 1-5 The flexible circuit board 100 for wear detection is shown. The flexible circuit board 100 and the main control board 202 are installed inside the device body 201, and the flexible circuit board 100 is electrically connected to the main control board 202. Specifically, the detection channel layer 1 of the flexible circuit board 100 is located on the side of the device body 201 closer to the human body to facilitate the detection of whether the wearable device is being worn. The signals detected by the flexible circuit board 100 are sent to the main control board 202 for processing and judgment.

[0047] Specifically, one side of the heat dissipation layer 4 of the flexible circuit board 100 extends and covers the main control board 202. The heat dissipation layer 4 can be connected to the main control board 202 via an adhesive layer 203. The adhesive layer 203 on the flexible circuit board 100 facilitates connection to the main control board 202, improving production efficiency. It should be noted that a shielding shell can be provided on the outside of the main control board 202, and the flexible circuit board 100 can be connected to the shielding shell via the adhesive layer 203.

[0048] The wearable device 200 also includes a detection chip integrated on the main control board 202. The detection chip is electrically connected to both the main control board 202 and the flexible circuit board 100. The detection chip processes physical signals (such as capacitance values) collected by the flexible circuit board 100 into electrical signals (such as voltage, current, or digital signals), and then sends these electrical signals to the main control board 202 to determine the wearing status of the wearable device. In some embodiments, the detection chip can be a capacitance detection chip, which determines the wearing status of the wearable device by collecting changes in capacitance values.

[0049] In this embodiment, the wearable device is smart glasses, and the device body 201 is the temple of the glasses. A main control board 202 is located at the end of the temple, and a flexible circuit board 100 is located at the point where the temple contacts the head for easy wear detection. Specifically, when the main control board 202 determines that the smart glasses are being worn, it can control the smart glasses to power on; if the determination is that the smart glasses are not being worn, the main control board 202 can control the smart glasses to power off or enter a low-power mode.

[0050] This invention provides a wearability detection flexible circuit board and a wearable device. The wearability detection flexible circuit board includes a detection channel layer, a reference channel layer, a ground layer, and a heat dissipation layer stacked sequentially. A first insulating dielectric layer is disposed between the detection channel layer and the reference channel layer, and a second insulating dielectric layer is disposed between the reference channel layer and the ground layer. By incorporating a ground layer, this wearability detection flexible circuit board can reduce the impact of main control board temperature changes on the wearability detection temperature coefficient, thereby improving the stability of wearability detection.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A wear detection flexible circuit board, characterized in that, The flexible circuit board (100) includes a detection channel layer (1), a reference channel layer (2), a ground layer (3) and a heat dissipation layer (4) stacked in sequence. A first insulating dielectric layer (5) is provided between the detection channel layer (1) and the reference channel layer (2), and a second insulating dielectric layer (6) is provided between the reference channel layer (2) and the ground layer (3).

2. The flexible circuit board according to claim 1, characterized in that, The flexible circuit board (100) further includes a shielding layer (7) stacked between the reference channel layer (2) and the ground layer (3), a third insulating dielectric layer (8) is disposed between the shielding layer (7) and the ground layer (3), and a second insulating dielectric layer (6) is disposed between the reference channel layer (2) and the shielding layer (7).

3. The flexible circuit board according to claim 1 or 2, characterized in that, The flexible circuit board (100) also includes an adhesive backing layer (9), and the grounding layer (3) is fixed to the heat dissipation layer (4) through the adhesive backing layer (9).

4. The flexible circuit board according to claim 2, characterized in that, The circumferential edge size of the detection channel layer (1) and the circumferential edge size of the reference channel layer (2) are the same, and the circumferential edge size of the ground layer (3) is at least a first predetermined size larger than the circumferential edge size of the detection channel layer (1).

5. The flexible circuit board according to claim 4, characterized in that, The circumferential edge size of the detection channel layer (1), the circumferential edge size of the shielding layer (7) and the circumferential edge size of the grounding layer (3) increase sequentially, and the circumferential edge size of the shielding layer (7) is a second predetermined size smaller than the circumferential edge size of the grounding layer (3).

6. The flexible circuit board according to claim 1, characterized in that, The grounding layer (3) and the heat dissipation layer (4) are copper-clad graphite sheets.

7. The flexible circuit board according to claim 1 or 2, characterized in that, The heat dissipation layer (4) is a graphite sheet.

8. The flexible circuit board according to claim 1, characterized in that, The detection channel layer (1) includes multiple spaced metal contacts, and the reference channel layer (2) includes multiple spaced metal contacts.

9. A wearable device, characterized in that, The wearable device (200) includes: Equipment body (201); The main control board (202) is installed inside the device body (201); The flexible circuit board (100) as described in any one of claims 1-8 is installed inside the device body (201) and the detection channel layer (1) is located on the side of the device body (201) closer to the human body, one side of the heat dissipation layer (4) extends and covers the main control board (202), and the flexible circuit board (100) is electrically connected to the main control board (202).

10. The wearable device according to claim 9, characterized in that, The heat dissipation layer (4) is connected to the main control board (202) through the adhesive layer (203).

11. The wearable device according to claim 9, characterized in that, The wearable device (200) also includes a detection chip integrated on the main control board (202), and the detection chip is electrically connected to the main control board (202) and the flexible circuit board (100) respectively.

Images