Capacitive sensor based on a twisted wire structure, desk lamp, device

Abstract

The utility model relates to a kind of capacitive sensor based on stranded wire structure, desk lamp, equipment, including capacitive digital conversion circuit, processing module, conductor and connecting wire;Conductor is set in the effective sensing area of target object as touch and / or proximity sensing capacitive detection electrode;Connecting wire is located in the non-effective sensing area of target object, including first transmission line, second transmission line, first transmission line, second transmission line with insulating stranded winding way mutually accompanied wire, and one end of first transmission line, second transmission line is respectively coupled to the self-capacitance measurement channel of capacitive digital conversion circuit, and the other end of first transmission line is coupled capacitive detection electrode;Processing module is coupled capacitive digital conversion circuit, for the difference value output detection and / or control signal according to the self-capacitance of first transmission line, second transmission line.

Description

Technical Field

[0001] This utility model relates to capacitance detection technology, and more particularly to a capacitance sensor, a desk lamp, and a device based on a twisted wire structure. Background Technology

[0002] With the widespread application of capacitance sensing technology, capacitive sensing control has become one of the important methods for realizing human-computer interaction. In practical applications, the electrodes for touch or proximity sensing are often placed at a distance from the detection chip, such as the metal ball on the top of a desk lamp or the metal logo on the casing of a device. However, during long-distance wiring, the connecting wires themselves introduce large distributed capacitance and environmental interference, leading to a decrease in the signal-to-noise ratio of the detection signal, reduced touch sensitivity, and even false triggering when a person touches the pipe through which the transmission line runs.

[0003] In existing technologies, shielding is typically used to suppress interference during transmission. While shielding can suppress external electromagnetic interference to some extent, it is costly and requires thicker wires, making it unsuitable for deployment in space-constrained or long-distance scenarios.

[0004] Therefore, it is necessary to provide an improved solution that is low-cost, easy to wire, has strong anti-interference capabilities, and is suitable for long-distance capacitive signal transmission, in order to improve the reliability and applicability of touch or proximity detection. Utility Model Content

[0005] This invention aims to solve the problem that existing capacitive touch / proximity sensors, when laid over long distances, are prone to external interference introduced by the connecting wires, resulting in low signal-to-noise ratio and high false trigger rate. Simultaneously, it provides a low-cost, flexible, and interference-resistant capacitive sensing solution, enabling its application on conductive components of devices to achieve accurate touch or proximity sensing.

[0006] To address the aforementioned problems, the core of this utility model provides a capacitive sensor based on a twisted wire structure, comprising a capacitance-to-digital conversion circuit, a processing module, a conductor, and connecting wires. The conductor is disposed in the effective sensing area of ​​the target object as a capacitance detection electrode for touch and / or proximity sensing. The connecting wires are located in the non-effective sensing area of ​​the target object and include a first transmission line and a second transmission line. The first and second transmission lines are routed together in an insulated twisted manner. One end of the first and second transmission lines is coupled to the self-capacitance measurement channel of the capacitance-to-digital conversion circuit, and the other end of the first transmission line is coupled to the capacitance detection electrode. The processing module is coupled to the capacitance-to-digital conversion circuit and is used to output detection and / or control signals based on the differential value of the self-capacitance of the first and second transmission lines.

[0007] Compared with the prior art, the capacitive sensor structure of this utility model has the following advantages:

[0008] 1. Anti-interference: By using a twisted wire structure in conjunction with differential settings, various signals in non-effective sensing areas are canceled out by differential, while signals in effective sensing areas are preserved, thus solving the problem of interference received on the line transmission path and improving the signal-to-noise ratio;

[0009] 2. Suitable for long-distance sensing: It overcomes the defect of the sharp drop in sensitivity after the extension of the wires of traditional capacitive sensors, and the sensing electrodes can be placed far away from the processing circuit.

[0010] 3. Low cost and easy to implement: The transmission medium uses ordinary twisted-pair cable that can be purchased, eliminating the need for expensive and thick shielded cables, thus reducing material costs and wiring difficulty.

[0011] 4. High integration: The product's inherent metal components can be used directly as sensing electrodes without changing the product's appearance or adding extra controls, thus achieving an invisible interactive interface.

[0012] The capacitive sensor of this utility model also includes the following extended and optimized auxiliary technical solutions:

[0013] The sensor is equipped with a switch matrix controlled by the processing module, and each transmission line is connected to a digital conversion circuit via an electrically controlled switch coupled to a capacitor within the switch matrix. By introducing the switch matrix, flexible configuration and management of the connection between the transmission lines and the measurement channels are achieved, enhancing the system's scalability and maintainability.

[0014] The first and second transmission lines can use conductors of different specifications, and the signal-to-noise ratio is ensured through program calibration. More preferably, the second transmission line uses an auxiliary conductor of the same specification as the first transmission line to ensure that both have highly consistent electrical characteristics (such as distributed capacitance, inductance, and impedance) during twisting and routing. Through symmetry, interference received in the transmission section acts on both transmission lines simultaneously and with the same amplitude in common-mode form, and subsequent differential signals cancel each other out to the maximum extent.

[0015] In this configuration, the end of the second transmission line closest to the effective sensing area is electrically floating, which avoids introducing additional capacitance at the endpoint of the second transmission line, improves the effectiveness of the differential signal, and makes it easier for the processing module to identify the real sensing signal that only occurs on the conductor connected to the first transmission line.

[0016] As a preferred option, the excitation signal of the capacitor-to-digital converter circuit can be configured to 100kHz-6MHz to avoid the increase in inductive reactance caused by high frequencies in the twisted-pair structure.

[0017] In one preferred embodiment, the conductor and the first transmission line are an integral structure; or, the conductor and the first transmission line are two separate components that are interconnected.

[0018] As an exemplary application, this utility model also provides a desk lamp, including the aforementioned capacitive sensor based on a twisted wire structure, wherein the effective sensing area is a decorative or functional conductive component on the desk lamp. This solution transforms existing metal parts (such as decorative metal balls) on the desk lamp into a touch-sensitive interface, eliminating the need for additional openings or attaching independent touch electrodes, achieving a seamless and aesthetically pleasing design, and enhancing the product's technological feel and user experience.

[0019] Furthermore, the lamp head is mounted on the base via the lamp post. The capacitance-to-digital conversion circuit and processing module are housed within the lamp base. Connecting wires extend from the base and pass through the lamp post, enabling the capacitance-to-digital conversion circuit to perform long-distance capacitance detection on the conductive components of the lamp head. This structural design utilizes the lamp's internal space, concealing the core circuitry within the base and embedding the connecting wires within the lamp post, maintaining a clean appearance. The twisted-pair structure addresses the issue of interference with capacitance signals during long-distance transmission, ensuring stable and accurate detection of touch operations at the lamp head location by the circuitry within the base, achieving reliable long-distance capacitance sensing.

[0020] As another exemplary application, this utility model also provides a device, such as a household appliance or transportation device, including a decorative or functional conductive component. Part or all of the conductive component serves as an effective sensing area, and capacitive sensing control is achieved through the aforementioned capacitive sensor based on a twisted wire structure. Further, the conductive component is an identification component on the device casing. By using a metal identifier (such as a logo) on the device casing as a touch key, users can trigger specific functions by touching the brand identifier, enhancing the user experience. Attached Figure Description

[0021] Figure 1 A schematic diagram of the capacitive sensor based on a twisted wire structure according to this invention is provided.

[0022] Figure 2a A schematic diagram of the dual-region detection structure is given. Figure 2b Given Figure 2a A schematic diagram of the four-region detection structure is given.

[0023] Figure 3 A schematic diagram of a capacitive sensor applied to a desk lamp is given.

[0024] Figure 4 A schematic diagram of a capacitive sensor applied to a metal marking on a device is provided. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that these embodiments are only used to explain the present utility model and are not intended to limit the scope of protection of the present utility model.

[0026] Example 1. Capacitive sensor based on stranded wire structure

[0027] Reference Figure 1 This embodiment provides a capacitive sensor based on a twisted wire structure, the core of which includes: a capacitance-to-digital converter (CDC), a processing module, a conductor 12, and connecting wires. The capacitance-to-digital converter, the switch matrix, and the processing module are integrated into the same detection chip 11, achieving miniaturization.

[0028] Conductor 12 is disposed in the target area where touch or proximity needs to be detected, i.e., the effective sensing area 13, as a capacitive detection electrode for touch and / or proximity sensing. Conductor 12 can be a metal sheet, metal ring, or a decorative or functional metal component already present on the product, of any shape. Conductor 12 can also be an extension of the first transmission line Cin+ over the second transmission line Cin-, and is integrally formed with the first transmission line Cin+.

[0029] The connecting wire is used to connect the distal conductor 12 to the proximal detection chip 11, located in the non-effective sensing area. The connecting wire consists of a first transmission line Cin+ and a second transmission line Cin-. The two transmission lines are preferably wires of the same diameter and material, and are run together in an insulated twisted manner to form a twisted pair structure.

[0030] One end of the first transmission line Cin+ is coupled to conductor 12, and the other end is connected through a self-capacitance measurement channel of the capacitance-to-digital converter circuit. The second transmission line Cin- serves as an auxiliary reference line, with one end not connected to any functional electrode and in an electrically floating state. The other end of the second transmission line Cin- is coupled to another self-capacitance measurement channel of the capacitance-to-digital converter circuit.

[0031] The processing module is connected to the capacitance-to-digital converter circuit, and the CDC is configured as a differential input. The CDC's built-in hardware structure directly outputs the differential self-capacitance of the first transmission line Cin+ and the second transmission line Cin- as a hardware differential output. When there is no touch or proximity event, due to the symmetry of the twisted pair, the capacitance changes generated by the received interference in the transmission segment on the two lines are basically equal, the CDC differential output cancels out, and the differential self-capacitance tends to zero.

[0032] When a user touches or approaches the conductor 12 in the effective sensing area 13, the self-capacitance of the conductor 12 connected by the first transmission line Cin+ undergoes a significant change, while the capacitance of the second transmission line Cin- remains almost unchanged. At this time, a noticeable change occurs in the differential value. The processing module identifies the differential change and outputs a detection signal (e.g., transmitting the detection signal value from CPU1 to CPU2) and / or a control command (e.g., controlling the action of a control component).

[0033] As an improvement, a switch matrix controlled by the processing module can be added. The switch matrix can be implemented using multiple analog switches, with the processing module controlling the on / off state of the electrically controlled switches within the switch matrix. (Reference) Figure 2a , Figure 2b The sensor has two or more sets of conductive bodies and connecting wires that sense different areas. Each transmission line is coupled to a digital conversion circuit with an electronically controlled switch in the switch matrix, enabling flexible configuration and management.

[0034] Example 2. Capacitive sensor applied to a desk lamp

[0035] Reference Figure 3 In this embodiment, the capacitive sensor described above is specifically applied to a desk lamp product. The desk lamp includes a lamp head 21, a lamp pole 22, and a base 23. A decorative metal ball 211 is provided on the lamp head 21, which directly serves as a conductor for touch or proximity sensing.

[0036] The detection chip 11 is installed inside the base 23 of the desk lamp. The connecting wire is a thin twisted pair cable, which is led out from inside the base 23, passes through the hollow lamp post 22, and extends to the lamp head 21, finally reliably electrically connecting the end of the first transmission line Cin+ to the metal ball 211. The end of the second transmission line Cin- remains floating inside the lamp head.

[0037] When a user touches or approaches the metal ball in the lamp head, the processing module accurately identifies the touch or proximity event through the differential capacitance signal output by the CDC, and controls the lamp's on / off state, dimming, or color adjustment accordingly.

[0038] Example 3. Capacitive sensor applied to a device

[0039] refer to Figure 4 In this embodiment, the capacitive sensor described above is applied to a device with metal components. The metal on the device housing 31 serves as the effective sensing area 13, and its back side is connected to one end of the first transmission line Cin+ via conductive adhesive or a physical connection. The detection chip 11 is located on the device's motherboard. Connecting wires extend from the motherboard and are arranged as long lines inside the device.

[0040] When a user touches or approaches metal, the sensor detects the event. The device then uses this signal to perform actions such as waking up the system, starting up, or unlocking the device.

[0041] Furniture doors can be used as one application form of the aforementioned device, with the touch interface exposed on the door panel surface and the detection chip built into the door body, balancing ease of operation and security. Traditional solutions typically require two sets of detection chips, one inside and one outside the door, to avoid excessive sensing distance. However, using this new technology, only a single detection chip is needed to achieve effective touch control on both sides of the door, significantly reducing the probability of false triggering while ensuring security.

[0042] In the field of transportation, the device can take another form: the metal brand logo (such as LOGO) on the vehicle shell is used as the sensing area, the detection chip is located on the main control board, and it is connected to the logo area through an extension line to form an implicit interactive interface, which takes into account both aesthetics and functionality.

[0043] Home appliances represent a third typical application scenario, including products such as washing machines, dishwashers, and refrigerators. Traditional capacitive touch solutions are limited by wiring, requiring the PCB board to be directly mounted on the back of the touch panel, with electrodes arranged on the front and the controller on the back. As functional requirements increase, touch panels are designed as elongated strips to accommodate multiple electrode points. This new technology supports flexible touch terminal layout, adapting to human-computer interaction habits while conforming to the internal structural constraints of the product, enhancing control expansion capabilities, and ensuring system reliability.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A capacitive sensor based on a stranded wire structure, characterized in that: Includes a capacitor-to-digital converter circuit, a processing module, conductors, and connecting wires; The conductor is disposed in the effective sensing area of ​​the target object as a capacitive detection electrode for touch and / or proximity sensing; The connecting wire is located in the non-effective sensing area of ​​the target object and includes a first transmission line and a second transmission line. The first transmission line and the second transmission line are routed together in an insulated twisted manner. One end of the first transmission line and the second transmission line are respectively coupled to the self-capacitance measurement channel of the capacitance digital conversion circuit, and the other end of the first transmission line is coupled to the capacitance detection electrode. The processing module is coupled with a capacitor-to-digital converter circuit, used to output detection and / or control signals based on the differential value of the self-capacitance of the first transmission line and the second transmission line.

2. The capacitive sensor according to claim 1, characterized in that: It includes a switch matrix controlled by the processing module, with each transmission line coupled to the capacitor-to-digital converter circuit via an electrically controlled switch in the switch matrix.

3. The capacitive sensor according to claim 1, characterized in that: The second transmission line is an auxiliary conductor of the same specification as the first transmission line.

4. The capacitive sensor according to claim 1, characterized in that: The end of the second transmission line closest to the effective sensing area is in an electrically floating state.

5. The capacitive sensor according to claim 1, characterized in that: The conductor and the first transmission line are an integral structure; or the conductor and the first transmission line are two separate components that are connected to each other.

6. A table lamp, characterized in that, The invention includes a capacitive sensor based on a stranded wire structure as described in any one of claims 1-5, wherein the effective sensing area is a decorative or functional conductive component on the table lamp.

7. The desk lamp according to claim 6, characterized in that: The lamp head of the desk lamp is mounted on the base via a lamp post. The capacitance digital conversion circuit and processing module are located inside the base. The connecting wire extends from the base and passes through the inside of the lamp post so that the capacitance digital conversion circuit can perform remote capacitance detection on the conductive components of the lamp head via the connecting wire.

8. A device comprising a decorative or functional conductive component, characterized in that, Part or all of the conductive component serves as the effective sensing area, and capacitive sensing control is achieved through a capacitive sensor based on a stranded wire structure as described in any one of claims 1-5.

9. The device according to claim 8, characterized in that: The conductive component is an identification component on the device casing.

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