Capacitive stylus and method of use thereof

Abstract

This invention provides a capacitive stylus and its usage method, belonging to the field of stylus technology. The capacitive stylus includes: a stylus shell; a pen tip installed in the lower part of the stylus shell; and an adjustment mechanism comprising a magnetorheological fluid cavity, a rotating sleeve, a guide groove, a connecting shaft, an electromagnetic coil, and a magnetic ring. Multiple guide grooves are provided, and two electromagnetic coils and two magnetic rings are provided. The magnetorheological fluid cavity is located in the upper part of the pen tip. By setting a magnetorheological fluid cavity, a rotating sleeve, and symmetrically arranged electromagnetic coils and magnetic rings within the pen tip, and utilizing the reversible viscosity change of the magnetorheological fluid under a magnetic field, stepless continuous adjustment of writing damping within the range of 10-150 mN·m is achieved. Users can freely adjust the pen tip rotation resistance according to personal preference or different writing scenarios, significantly improving the stylus's personalized adaptability and writing experience.

Description

Technical Field

[0001] This invention belongs to the field of stylus technology, specifically relating to a capacitive stylus and its usage method. Background Technology

[0002] A stylus is an input device designed specifically for touchscreens, simulating or enhancing finger touch to achieve a more precise and nuanced user experience. There are two main types: passive capacitive styluses rely on a conductive tip to simulate the human body's electric field, requiring no power source, and are simple in structure and inexpensive, suitable for basic selection and writing; active styluses, on the other hand, have built-in chips and batteries, communicate with devices via Bluetooth, support advanced features such as pressure sensitivity levels, tilt sensing, and anti-mistouch, and can capture changes in stroke thickness and angle to meet the demanding needs of professional drawing and note-taking. With the widespread adoption of mobile office and digital creation, styluses have become an important productivity extension for tablets and 2-in-1 devices, redefining the digital boundaries of handwriting and drawing with their low latency, high precision, and deep integration with the system ecosystem. Modern styluses are also increasingly integrating innovative features such as wireless charging, magnetic storage, and gesture control, evolving from simple writing tools into intelligent interactive carriers that combine artistic expression and efficiency enhancement.

[0003] In existing technologies, the damping feel between the pen tip and the screen is fixed when writing with a capacitive stylus. It cannot be steplessly adjusted according to user preferences or different writing scenarios. Furthermore, when the pen tip contacts the screen, it is prone to unstable signal and insufficient writing accuracy due to angle deviation or uneven pressure, which affects the writing experience and control accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a capacitive stylus and its usage method, aiming to solve the problems in the prior art where the damping feel between the pen tip and the screen is fixed and cannot be infinitely adjusted according to user preferences or different writing scenarios, and the pen tip is prone to unstable signal and insufficient writing accuracy due to angle deviation or uneven pressure when in contact with the screen, thus affecting the writing experience and control accuracy.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A capacitive stylus includes: Stylus shell; The pen tip is installed inside the lower part of the stylus shell; An adjustment mechanism includes a magnetorheological fluid cavity, a rotating sleeve, a guide groove, a connecting shaft, an electromagnetic coil, and a magnetic ring. Multiple guide grooves are provided, and two electromagnetic coils and two magnetic rings are provided. The magnetorheological fluid cavity is located in the upper part of the pen tip and is filled with magnetorheological fluid. The rotating sleeve is rotatably connected to the pen tip and is T-shaped, with its upper part located within the magnetorheological fluid cavity. The connecting shaft is fixedly connected to the upper end of the rotating sleeve and rotatably connected to the upper inner wall of the magnetorheological fluid cavity. Multiple guide grooves are located at the upper end of the rotating sleeve, and the rotating sleeves are all stepped structures. Two electromagnetic coils are symmetrically installed inside the pen tip, with each electromagnetic coil located on one side of the magnetorheological fluid cavity. Two magnetic rings are fixedly connected to the pen tip, with each magnetic ring located on the outer side of the magnetorheological fluid cavity and the inner side of the two electromagnetic coils. A pen tip assembly, comprising a conductive pen tip, a V-shaped pen tip, and a metal electrode, wherein the conductive pen tip is fixedly connected to the lower end of a rotating bushing and rotatably connected inside the pen tip; the V-shaped pen tip is fixedly connected to the lower end of the conductive pen tip; a metal motor is installed inside the conductive pen tip and the V-shaped pen tip; the conductive pen tip and the V-shaped pen tip form an arrowhead-shaped structure; and A control component is installed inside the stylus housing and located above the adjustment mechanism. The control component controls the operation of the adjustment mechanism.

[0006] In a preferred embodiment of the present invention, the control component includes an adjustment circuit board, a wireless communication module, a microcontroller, a current drive module, a power supply module, a display slot, an adjustment knob, and two indicator lights. The adjustment circuit board is fixedly connected to the lower part of the stylus shell, the power supply module is fixedly connected to the upper part of the stylus shell, the wireless communication module is fixedly connected to the surface of the adjustment circuit board, the microcontroller is fixedly connected to the surface of the adjustment circuit board, and the microcontroller is electrically connected to two electromagnetic coils. The current drive module is fixedly connected to the surface of the adjustment circuit board and is electrically connected to the power supply module and the microcontroller. The display slot has an opening on the upper part of the circumferential surface of the stylus shell. The adjustment knob rotates on the inner wall of the display slot. Both indicator lights are fixedly connected to the inner wall of the display slot and are electrically connected to the microcontroller. The adjustment knob is electrically connected to the microcontroller.

[0007] As a preferred embodiment of the present invention, a sealing ring is fixedly connected inside the pen tip. The sealing ring is located at the connection between the magnetorheological fluid cavity and the rotating bushing. The inner layer of the sealing ring is a polytetrafluoroethylene rotary sealing ring, and the outer layer is a fluororubber O-ring.

[0008] As a preferred embodiment of the present invention, a main circuit board is fixedly connected inside the stylus shell. The main circuit board is located below the power module and above the adjustment circuit board. An accelerometer and two Bluetooth modules are fixedly connected to the surface of the main circuit board.

[0009] In a preferred embodiment of the present invention, a pressure sensor is fixedly connected to the lower part of the rotating bushing, and the pressure sensor is in contact with the upper end of the conductive pen tip.

[0010] As a preferred embodiment of the present invention, an upper cover is threadedly connected to the upper part of the inner circumference of the stylus shell, a charging interface is installed inside the upper cover, the charging interface is electrically connected to the power module, and a rubber plate is fixedly connected to the upper end of the upper cover, the rubber plate being embedded in the upper cover to protect the charging interface.

[0011] As a preferred embodiment of the present invention, grooves for holding are provided on both sides of the circumferential surface of the stylus shell, and grip pads are fixedly connected in both grooves.

[0012] As a preferred embodiment of the present invention, the upper end of the pen tip is provided with an inlet channel and an outlet channel, and both the inlet channel and the outlet channel are threaded with sealing bolts.

[0013] In a preferred embodiment of the present invention, a bearing is fixedly connected inside the pen tip, and the bearing is mounted on the circumferential surface of the conductive pen tip.

[0014] As a preferred embodiment of the present invention Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, by setting a magnetorheological fluid cavity, a rotating bushing, and symmetrically arranged electromagnetic coils and magnetic rings inside the pen tip, the writing damping is continuously adjustable within the range of 10-150 mN·m by utilizing the characteristic that the viscosity of the magnetorheological fluid changes reversibly under the action of a magnetic field. Users can freely adjust the pen tip rotation resistance according to their personal preferences or different writing scenarios, which significantly improves the personalized adaptability of the stylus and the writing experience.

[0015] 2. In this invention, by setting an accelerometer to collect writing speed and tilt angle in real time, a pressure sensor to detect pen tip contact pressure, and combining it with the microcontroller's adaptive algorithm, automatic dynamic adjustment of damping is achieved—automatically reducing damping to improve smoothness during high-speed swiping and automatically increasing damping to enhance control precision during fine outlining. At the same time, the V-shaped pen tip structure and metal electrode work together to ensure accurate signal transmission, and the pressure sensor transmits pressure-sensitive signals in real time to trigger changes in pen thickness, effectively solving the problems of single fixed damping and insufficient writing precision in existing touch pens.

[0016] 3. In this invention, the electromagnetic coil, magnetic ring, magnetorheological fluid cavity, and rotating bushing are integrated inside the pen tip. Reliable sealing is achieved with bearing support and a double-layer composite sealing ring. The structure is compact and does not increase the pen body diameter. The magnetorheological fluid can be maintained regularly through the inlet and outlet channels. The rubber plate on the top cover protects the charging interface, and the grip pad improves writing comfort for long periods of time. The overall structure has the comprehensive advantages of convenient maintenance, reliable battery life, and comfortable grip. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a perspective view of the present invention; Figure 2 This is a side view of the present invention; Figure 3 For the present invention Figure 2 A magnified view of a section at point A in the middle; Figure 4 This is a cross-sectional view of the present invention; Figure 5 For the present invention Figure 4 A magnified view of a section at point B in the middle; Figure 6 For the present invention Figure 4 A magnified view of a section at point C; Figure 7 This is a flowchart illustrating the usage of the adjustment component described in this invention. Figure 8 This is a flowchart illustrating the usage process of the present invention.

[0018] In the diagram: 1. Stylus shell; 2. Pen tip; 201. Magnetorheological fluid chamber; 202. Rotating bushing; 2021. Guide groove; 203. Connecting shaft; 204. Bearing; 205. Conductive pen tip; 2051. V-shaped pen tip; 206. Pressure sensor; 207. Sealing ring; 208. Electromagnetic coil; 209. Magnetic ring; 210. Sealing bolt; 211. Adjustment circuit board; 212. Wireless communication module; 213. Microcontroller; 214. Current drive module; 3. Main circuit board; 301. Accelerometer; 302. Bluetooth module; 4. Top cover; 401. Rubber plate; 402. Charging interface; 403. Power module; 5. Grip pad; 6. Display slot; 601. Adjustment knob; 602. Indicator light. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 Please see Figures 1-5 The present invention provides the following technical solutions: A capacitive stylus includes: Stylus shell 1; Pen tip 2 is installed inside the lower part of the stylus shell 1; The adjustment mechanism includes a magnetorheological fluid cavity 201, a rotating sleeve 202, a guide groove 2021, a connecting shaft 203, an electromagnetic coil 208, and a magnetic ring 209. Multiple guide grooves 2021 are provided, and two electromagnetic coils 208 and two magnetic rings 209 are provided. The magnetorheological fluid cavity 201 is located in the upper part of the pen tip 2 and is filled with magnetorheological fluid. The rotating sleeve 202 is rotatably connected to the pen tip 2 and is T-shaped. The upper part of the rotating sleeve 202 is located within the magnetorheological fluid cavity 201. The connecting shaft 2021... 3. The upper end of the rotating bushing 202 is fixedly connected to the connecting shaft 203, which is rotatably connected to the upper inner wall of the magnetorheological fluid cavity 201. Multiple guide grooves 2021 are opened at the upper end of the rotating bushing 202. The multiple rotating bushings 202 are all stepped structures. Two electromagnetic coils 208 are symmetrically installed in the pen tip 2. The two electromagnetic coils 208 are respectively located on both sides of the magnetorheological fluid cavity 201. Two magnetic rings 209 are fixedly connected in the pen tip 2. The two magnetic rings 209 are located on the outer side of the magnetorheological fluid cavity 201 and the inner side of the two electromagnetic coils 208. The pen tip assembly includes a conductive pen tip 205, a V-shaped pen tip 2051, and metal electrodes. The conductive pen tip 205 is fixedly connected to the lower end of the rotating bushing 202 and rotatably connected inside the pen head 2. The V-shaped pen tip 2051 is fixedly connected to the lower end of the conductive pen tip 205. A metal motor is installed inside the conductive pen tip 205 and the V-shaped pen tip 2051. The conductive pen tip 205 and the V-shaped pen tip 2051 form an arrowhead-shaped structure. The control component is installed inside the stylus shell 1 and is located on the upper side of the adjustment mechanism. The control component controls the operation of the adjustment mechanism.

[0021] In a specific embodiment of the present invention, the stylus shell 1 is a cylindrical hollow shell made of aluminum alloy or engineering plastic, with an internal accommodating space. The pen tip 2 is installed in the lower inner part of the stylus shell 1. The pen tip 2 has a stepped cylindrical structure and is fixedly connected to the stylus shell 1 by threads or snaps. The adjustment mechanism includes a magnetorheological fluid cavity 201, a rotating bushing 202, a guide groove 2021, a connecting shaft 203, an electromagnetic coil 208, and a magnetic ring 209. The magnetorheological fluid cavity 201 is located in the upper inner part of the pen tip 2 and is an annular closed chamber filled with magnetorheological fluid, which is composed of micron-sized carbonyl iron powder, silicone oil, and additives. The rotating bushing 202 has a T-shaped structure and is rotatably connected to the pen tip 2. The upper part of the rotating bushing 202 is located inside the magnetorheological fluid cavity 201, and the lower part of the rotating bushing 202 extends to the lower part of the pen tip 2. A connecting shaft 203 is fixedly connected to the upper center of the rotating sleeve 202, and the upper end of the connecting shaft 203 is rotatably connected to the upper inner wall of the magnetorheological fluid cavity 201. Multiple guide grooves 2021 are provided, all located on the upper end face of the rotating sleeve 202, and are radially distributed to enhance the shearing effect between the rotating sleeve 202 and the magnetorheological fluid. Two electromagnetic coils 208 are provided, symmetrically installed inside the pen tip 2, with the two electromagnetic coils 208 respectively located on both sides of the magnetorheological fluid cavity 201. The electromagnetic coils 208 are made of enameled copper wire. Two magnetic guide rings 209 are provided, both fixedly connected inside the pen tip 2. The two magnetic guide rings 209 are located on the outer side of the magnetorheological fluid cavity 201 and the inner side of the two electromagnetic coils 208. The magnetic guide rings 209 are made of pure iron or silicon steel sheets and are used to concentrate magnetic lines of force. The pen tip assembly includes a conductive pen tip 205, a V-shaped pen tip 2051, and metal electrodes. The conductive pen tip 205 is fixedly connected to the lower end of the rotating bushing 202 and rotatably connected inside the pen head 2. The conductive pen tip 205 is made of conductive PEEK material. The V-shaped pen tip 2051 is fixedly connected to the lower end of the conductive pen tip 205. The V-shaped pen tip 2051 has a V-shaped tip structure for precise positioning. The metal electrodes are installed inside the conductive pen tip 205 and the V-shaped pen tip 2051. The metal electrodes are connected to the signal generating circuit inside the stylus via wires for transmitting capacitive signals. The control component is installed inside the stylus housing 1 and located on the upper side of the adjustment mechanism. The control component is electrically connected to the electromagnetic coil 208 and is used to control the operation of the adjustment mechanism.

[0022] Please refer to the details. Figures 1-8The control components include an adjustment circuit board 211, a wireless communication module 212, a microcontroller 213, a current drive module 214, a power supply module 403, a display slot 6, an adjustment knob 601, and two indicator lights 602. The adjustment circuit board 211 is fixedly connected to the lower part of the stylus shell 1, the power supply module 403 is fixedly connected to the upper part of the stylus shell 1, the wireless communication module 212 is fixedly connected to the surface of the adjustment circuit board 211, and the microcontroller 213 is fixedly connected to the surface of the adjustment circuit board 211. The microcontroller 213 is connected to two electromagnetic wires. The current drive module 214 is fixedly connected to the surface of the adjustment circuit board 211. The current drive module 214 is electrically connected to the power module 403 and the microcontroller 213. The display slot 6 is opened on the upper part of the circumferential surface of the stylus shell 1. The adjustment knob 601 rotates on the inner wall of the display slot 6. Both indicator lights 602 are fixedly connected to the inner wall of the display slot 6. Both indicator lights 602 are electrically connected to the microcontroller 213. The adjustment knob 601 is electrically connected to the microcontroller 213.

[0023] In this embodiment: the adjustment circuit board 211 is fixedly connected to the lower inner part of the stylus shell 1, located above the pen tip 2. The power module 403 is fixedly connected to the upper inner part of the stylus shell 1, and the power module 403 uses a lithium-ion battery with a capacity of 100mAh. The wireless communication module 212 is fixedly connected to the surface of the adjustment circuit board 211, and uses a low-power Bluetooth chip. The microcontroller 213 is fixedly connected to the surface of the adjustment circuit board 211, and the microcontroller 213 is electrically connected to two electromagnetic coils 208. The current drive module 214 is fixedly connected to the surface of the adjustment circuit board 211, and the current drive module 214 uses an H-bridge constant current drive circuit, is electrically connected to the power module 403, and is electrically connected to the microcontroller 213, for receiving instructions from the microcontroller 213 and outputting an adjustable current of 0-500mA to the electromagnetic coils 208. The display slot 6 is formed on the upper part of the circumferential surface of the stylus shell 1, and is a rectangular groove structure. The adjustment knob 601 is rotatably connected to the inner wall of the display slot 6. The adjustment knob 601 has a rotary encoder structure and is electrically connected to the microcontroller 213. When the user rotates the adjustment knob 601, a pulse signal is generated and input to the microcontroller 213. Both indicator lights 602 are fixedly connected to the inner wall of the display slot 6 and are electrically connected to the microcontroller 213. They are used to indicate the current damping level by color or flashing frequency.

[0024] Please refer to the details. Figures 1-8 A sealing ring 207 is fixedly connected inside the pen tip 2. The sealing ring 207 is located at the connection between the magnetorheological fluid cavity 201 and the rotating bushing 202. The inner layer of the sealing ring 207 is a polytetrafluoroethylene rotary sealing ring, and the outer layer is a fluororubber O-ring.

[0025] In this embodiment, a sealing ring 207 is fixedly connected inside the pen tip 2. The sealing ring 207 is located at the connection between the magnetorheological fluid cavity 201 and the rotating bushing 202. The sealing ring 207 adopts a double-layer composite sealing structure. The inner layer is a polytetrafluoroethylene rotary sealing ring, which slides in contact with the circumferential surface of the rotating bushing 202, and has a low coefficient of friction and good wear resistance. The outer layer is a fluororubber O-ring, which is fitted around the outer circumference of the inner sealing ring to provide radial compression force, ensuring that a reliable static seal and dynamic seal are formed between the sealing ring 207 and the inner wall of the pen tip 2 and the rotating bushing 202, effectively preventing leakage of the magnetorheological fluid in the magnetorheological fluid cavity 201.

[0026] Please refer to the details. Figures 1-8 The stylus shell 1 has a main circuit board 3 fixedly connected inside. The main circuit board 3 is located below the power module 403 and above the adjustment circuit board 211. An accelerometer 301 and two Bluetooth modules 302 are fixedly connected to the surface of the main circuit board 3.

[0027] In this embodiment: A main circuit board 3 is fixedly connected inside the stylus shell 1. The main circuit board 3 is located below the power module 403 and above the adjustment circuit board 211, and is fixed to the inner wall of the stylus shell 1 by support pillars. An accelerometer 301 and two Bluetooth modules 302 are fixedly connected to the surface of the main circuit board 3. The accelerometer 301 is a three-axis MEMS accelerometer used to collect real-time data on the writing speed and tilt angle of the stylus. The two Bluetooth modules 302 use low-power Bluetooth 5.0 chips; one is used to communicate with external devices, such as tablets and mobile phones, and the other is used to exchange internal data with the wireless communication module 212 on the adjustment circuit board 211, realizing data synchronization between the main circuit board 3 and the adjustment circuit board 211.

[0028] Please refer to the details. Figures 1-8 A pressure sensor 206 is fixedly connected to the lower part of the rotating bushing 202, and the pressure sensor 206 is in contact with the upper end of the conductive pen tip 205.

[0029] In this embodiment, a pressure sensor 206 is fixedly connected to the lower inner part of the rotating bushing 202. The pressure sensor 206 is a thin-film piezoresistive sensor, and its lower end face contacts the upper end of the conductive pen tip 205. When the conductive pen tip 205 contacts the screen and applies pressure, the pressure is transmitted to the pressure sensor 206 through the conductive pen tip 205. The pressure sensor 206 converts the pressure signal into an electrical signal and transmits it to the microcontroller 213. The microcontroller 213 determines the writing force based on the pressure value and sends a pressure-sensitive signal to an external device through the Bluetooth module 302, triggering changes in the thickness of the pen strokes.

[0030] Please refer to the details. Figures 1-8The upper part of the inner circumference of the stylus shell 1 is threaded with an upper cover 4. A charging interface 402 is installed inside the upper cover 4. The charging interface 402 is electrically connected to the power module 403. A rubber plate 401 is fixedly connected to the upper end of the upper cover 4. The rubber plate 401 is embedded in the upper cover 4 to protect the charging interface 402.

[0031] In this embodiment: an upper cover 4 is threadedly connected to the upper part of the inner circumference of the stylus shell 1. The upper cover 4 is a cylindrical structure with external threads on its outer circumference, which mate with the internal threads on the upper inner wall of the stylus shell 1. A charging interface 402 is installed inside the upper cover 4. The charging interface 402 is a Type-C female connector and is electrically connected to the power module 403. A rubber plate 401 is fixedly connected to the upper end of the upper cover 4. The rubber plate 401 is embedded in the upper cover 4 and covers the outside of the charging interface 402. The rubber plate 401 can be flipped open to protect the charging interface 402 from dust and moisture contamination.

[0032] Please refer to the details. Figures 1-8 The stylus shell 1 has grooves on both sides of its circumferential surface for holding, and grip pads 5 are fixedly connected in both grooves.

[0033] In this embodiment: The stylus shell 1 has grooves for holding on both sides of its circumferential surface. The two grooves are symmetrically arranged, and their arc-shaped contours are adapted to the gripping posture of human fingers. Grip pads 5 are fixedly connected to both grooves. The grip pads 5 are made of silicone or TPU elastic material and have anti-slip textures on their surface to increase grip friction and improve comfort during extended writing sessions.

[0034] Please refer to the details. Figures 1-8 The upper end of the pen tip 2 is provided with an inlet channel and an outlet channel, and both the inlet channel and the outlet channel are threaded with sealing bolts 210.

[0035] In this embodiment, the upper end of the pen tip 2 has an inlet channel and an outlet channel, both of which are L-shaped through holes, communicating with the top and bottom of the magnetorheological fluid chamber 201, respectively. The inner walls of both the inlet and outlet channels are provided with internal threads, and two sealing bolts 210 are threaded into the inlet and outlet channels, respectively. By removing the sealing bolts 210, magnetorheological fluid can be injected into or discharged from the magnetorheological fluid chamber 201, facilitating regular maintenance and replacement of the liquid medium.

[0036] Please refer to the details. Figures 1-8 A bearing 204 is fixedly connected inside the pen tip 2, and the bearing 204 is installed on the circumferential surface of the conductive pen tip 205.

[0037] In this embodiment: a bearing 204 is fixedly connected inside the pen tip 2. The bearing 204 is a miniature rolling bearing, with its outer ring interference-fitted with the inner wall of the pen tip 2, and its inner ring fitted onto the circumferential surface of the conductive pen tip 205. The bearing 204 is installed between the conductive pen tip 205 and the pen tip 2 to support the rotation of the conductive pen tip 205, reduce rotational friction, and ensure that the conductive pen tip 205 can rotate flexibly and smoothly relative to the pen tip 2 during writing.

[0038] The working principle and usage process of this invention are as follows: First, the user charges the power module through the charging port inside the upper cover. The power module supplies power to the adjustment circuit board, main circuit board, and microcontroller. The upper cover is rotated to lock it securely to the stylus shell via threads. A rubber plate covers and protects the charging port. The microcontroller initializes and starts the wireless communication module, establishing a wireless connection with external devices via Bluetooth. The accelerometer and pressure sensor enter standby mode. The user selects either manual or automatic adjustment mode based on writing preference or usage scenario. In manual adjustment mode, the user rotates the adjustment knob inside the display slot. The knob transmits the rotation angle signal to the microcontroller. The microcontroller calculates the target current value based on the preset damping-current mapping relationship and controls the current drive module to output a corresponding PWM current to the two electromagnetic coils. The electromagnetic coils generate a ring-shaped magnetic field, which, after being concentrated by the magnetic ring, acts perpendicularly on the magnetorheological fluid cavity. Magnetic particles in the magnetorheological fluid arrange themselves into a chain-like structure along the magnetic field lines, increasing the fluid viscosity. The rotating bushing, under the action of the guide groove, experiences shear resistance between itself and the magnetorheological fluid. As the force increases, the damping torque is transmitted to the conductive pen tip through the connecting shaft and rotating bushing, thereby achieving stepless adjustment of writing damping. Two indicator lights display the current damping level in real time through color changes. In automatic adjustment mode, the accelerometer collects the writing speed and tilt angle of the stylus in real time, and the pressure sensor detects the contact pressure between the conductive pen tip and the screen. The microcontroller inputs the sensor data into a preset adaptive algorithm to calculate the target damping value adapted to the current writing scenario and automatically adjusts the electromagnetic coil current. This allows for automatic reduction of damping to improve smoothness when the writing speed is fast and automatic increase of damping to enhance control precision when the writing speed is slow or the pressure is increased. After setting the damping, the user holds the stylus shell with their fingers on the grip pad, placing the V-shaped tip in contact with the screen. The V-shaped tip structure ensures precise positioning. The metal electrodes emit capacitive signals, which are transmitted to the screen through the conductive tip. During writing, as the tip rotates relative to the screen, the rotating shaft rotates within the magnetorheological fluid chamber. The damping force provided by the magnetorheological fluid creates a stable writing resistance. Simultaneously, a pressure sensor monitors the tip pressure in real time. When the pressure exceeds a set threshold, the microcontroller sends a pressure-sensitive signal to an external device via Bluetooth, triggering changes in stroke thickness. The user can rotate the adjustment knob at any time during writing to change the damping. The microcontroller responds in real time and adjusts the electromagnetic coil current. Two indicator lights update the damping level display synchronously. Accelerometers and pressure sensors continuously monitor the writing status, enabling dynamic adjustment that automatically reduces damping during high-speed strokes and automatically increases damping during fine outlining.After writing is completed, a standby command is sent via an external device or adjustment knob. The microcontroller cuts off the power supply to the electromagnetic coil, and the magnetorheological fluid returns to a low viscosity state. The rotating bushing maintains flexible rotation with the cooperation of the bearing and the sealing ring. During maintenance, the magnetorheological fluid in the magnetorheological fluid chamber can be replenished or replaced periodically through the inlet and outlet channels. Tightening the sealing bolts achieves a seal. The stylus is placed in the storage position, and the rubber plate protects the charging interface from dust contamination.

[0039] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A capacitive stylus, characterized in that, include: Stylus shell (1); Pen tip (2), the pen tip (2) is installed inside the lower part of the stylus shell (1); The adjustment mechanism includes a magnetorheological fluid cavity (201), a rotating sleeve (202), a guide groove (2021), a connecting shaft (203), an electromagnetic coil (208), and a magnetic ring (209). Multiple guide grooves (2021) are provided, and two electromagnetic coils (208) and two magnetic rings (209) are provided. The magnetorheological fluid cavity (201) is located in the upper part of the pen tip (2) and is filled with magnetorheological fluid. The rotating sleeve (202) is rotatably connected to the pen tip (2). The rotating sleeve (202) is T-shaped, and its upper part is located within the magnetorheological fluid cavity (201). The connecting shaft (203)... The shaft (203) is fixedly connected to the upper end of the rotating bushing (202). The connecting shaft (203) is rotatably connected to the upper inner wall of the magnetorheological fluid cavity (201). Multiple guide grooves (2021) are opened at the upper end of the rotating bushing (202). Multiple rotating bushings (202) are stepped structures. Two electromagnetic coils (208) are symmetrically installed in the pen tip (2). The two electromagnetic coils (208) are respectively located on both sides of the magnetorheological fluid cavity (201). Two magnetic rings (209) are fixedly connected in the pen tip (2). The two magnetic rings (209) are located on the outer side of the magnetorheological fluid cavity (201) and the inner side of the two electromagnetic coils (208). A pen tip assembly, comprising a conductive pen tip (205), a V-shaped pen tip (2051), and a metal electrode, wherein the conductive pen tip (205) is fixedly connected to the lower end of a rotating bushing (202), the conductive pen tip (205) is rotatably connected inside a pen head (2), the V-shaped pen tip (2051) is fixedly connected to the lower end of the conductive pen tip (205), and a metal motor is installed inside the conductive pen tip (205) and the V-shaped pen tip (2051), the conductive pen tip (205) and the V-shaped pen tip (2051) forming an arrow-shaped structure; and The control component is installed inside the stylus shell (1) and is located on the upper side of the adjustment mechanism. The control component controls the operation of the adjustment mechanism.

2. A capacitive stylus according to claim 1, characterized in that: The control components include an adjustment circuit board (211), a wireless communication module (212), a microcontroller (213), a current drive module (214), a power supply module (403), a display slot (6), an adjustment knob (601), and two indicator lights (602). The adjustment circuit board (211) is fixedly connected to the lower part of the stylus shell (1), the power supply module (403) is fixedly connected to the upper part of the stylus shell (1), the wireless communication module (212) is fixedly connected to the surface of the adjustment circuit board (211), and the microcontroller (213) is fixedly connected to the surface of the adjustment circuit board (211). The microcontroller (213) is connected to two electromagnetic coils ( 208) Electrical connection, the current drive module (214) is fixedly connected to the surface of the adjustment circuit board (211), the current drive module (214) is electrically connected to the power module (403), the current drive module (214) is electrically connected to the microcontroller (213), the display slot (6) has an upper part of the circumferential surface of the stylus shell (1), the adjustment knob (601) rotates on the inner wall of the display slot (6), the two indicator lights (602) are fixedly connected to the inner wall of the display slot (6), the two indicator lights (602) are electrically connected to the microcontroller (213), and the adjustment knob (601) is electrically connected to the microcontroller (213).

3. A capacitive stylus according to claim 2, characterized in that: A sealing ring (207) is fixedly connected inside the pen tip (2). The sealing ring (207) is located at the connection between the magnetorheological fluid cavity (201) and the rotating bushing (202). The inner layer of the sealing ring (207) is a polytetrafluoroethylene rotary sealing ring, and the outer layer is a fluororubber O-ring.

4. A capacitive stylus according to claim 3, characterized in that: The stylus shell (1) is fixedly connected to a main circuit board (3). The main circuit board (3) is located on the lower side of the power module (403) and the upper side of the adjustment circuit board (211). An accelerometer (301) and two Bluetooth modules (302) are fixedly connected to the surface of the main circuit board (3).

5. A capacitive stylus according to claim 4, characterized in that: A pressure sensor (206) is fixedly connected to the lower part of the rotating bushing (202), and the pressure sensor (206) is in contact with the upper end of the conductive pen tip (205).

6. A capacitive stylus according to claim 5, characterized in that: The upper part of the inner circumference of the stylus shell (1) is threaded with an upper cover (4). A charging interface (402) is installed inside the upper cover (4). The charging interface (402) is electrically connected to the power module (403). A rubber plate (401) is fixedly connected to the upper end of the upper cover (4). The rubber plate (401) is embedded in the upper cover (4) to protect the charging interface (402).

7. A capacitive stylus according to claim 6, characterized in that: The stylus shell (1) has grooves for holding on both sides of its circumferential surface, and grip pads (5) are fixedly connected in both grooves.

8. A capacitive stylus according to claim 7, characterized in that: The upper end of the pen tip (2) is provided with an inlet channel and an outlet channel, and both the inlet channel and the outlet channel are threaded with sealing bolts (210).

9. A capacitive stylus according to claim 8, characterized in that: A bearing (204) is fixedly connected inside the pen tip (2), and the bearing (204) is installed on the circumferential surface of the conductive pen tip (205).

10. A method of using a capacitive stylus, comprising using a capacitive stylus as described in any one of claims 1-9, characterized in that, Includes the following steps: Step S1, Start-up: The power module supplies power, the microcontroller initializes, and it connects to external devices via the Bluetooth module; Step S2, Damping Adjustment: Rotate the adjustment knob, and the microcontroller controls the current drive module to output current to the electromagnetic coil. The electromagnetic coil generates a magnetic field, which acts on the magnetorheological fluid through the magnetic ring. The viscosity of the magnetorheological fluid changes, and the rotational damping of the rotating bushing changes accordingly; or the acceleration sensor and pressure sensor collect writing data in real time, and the microcontroller automatically calculates and adjusts the damping. Step S3, Writing: Hold the stylus, the V-shaped pen tip contacts the screen, and the metal electrode emits a capacitive signal; when writing, the rotating sleeve rotates in the magnetorheological fluid cavity to form damping resistance, and the pressure sensor detects the pen tip pressure and transmits the pressure signal. Step S4, Storage: Disconnect the power supply to the electromagnetic coil.

Images