Intelligent dual-mode all-dielectric digital input device and control method

Abstract

This invention relates to the field of digital technology, specifically disclosing an intelligent dual-mode all-media digital input device and its control method. The device includes a pen, a conductive textured sphere with optical features on its surface, an image acquisition and transmission unit, and a pressure detection unit. It constructs an integrated architecture based on the conductive textured sphere and a capacitive signal enhancement unit, with a microcontroller coordinating the operation of each unit. It can flexibly switch between screen interaction mode and independent input mode. In screen interaction mode, it functions as an active capacitive pen; in independent input mode, it can record optical flow trajectories on a physical surface based on the applied force, or control the cursor while suspended in the air. The device supports automatic media recognition switching based on the electrical characteristic signals of the contact surface and employs a push-rod floating imaging module structure, physically eliminating zoom blur in macro imaging and pseudo-displacement interference along the writing axis. It achieves multiple uses with a single pen, offering advantages such as strong adaptability to all scenarios and high trajectory reproduction accuracy.

Description

Technical Field

[0001] This invention belongs to the field of digital input technology, specifically relating to an intelligent dual-mode all-media digital input device and its control method. Background Technology

[0002] With the widespread adoption of mobile work and digital creativity, users frequently need to switch between tablets, paper notebooks, and AI glasses. However, existing handwriting input devices suffer from significant media fragmentation issues and have some limitations in their microscopic implementation.

[0003] I. Macroscopic-level media fragmentation and functional singularity

[0004] Most mainstream styluses currently available can only work on a single medium:

[0005] 1. Pure screen pens, such as active capacitive pens, mainly rely on scanning signals emitted by the screen for positioning. They become ineffective when removed from a specific screen, cannot be used to record inspiration on ordinary paper, cannot be used for handwriting input in AI glasses, and cannot be used as a mouse on a desktop.

[0006] 2. Pure paper pens, such as dot matrix pens, rely on expensive special paper covered with micro-dot matrix codes, and the pen tip is usually a regular ballpoint pen refill. Not only can they not be used as styluses to write on glass screens, but they are also expensive to use.

[0007] 3. Although traditional optical mouse pens can be used on desktops, they usually cannot provide the original handwriting pressure sensitivity, and the pen tip is too large, making it difficult to perform clicking and drawing on capacitive screens.

[0008] Therefore, there is an urgent need for a universal input tool that can break down the boundaries between screen and paper and adapt to various writing media.

[0009] II. The contradiction between optical imaging and pressure sensitivity at the microscopic level

[0010] To enable independent writing without a screen, photoelectric sensors are typically used to capture pen tip movement. However, with the introduction of continuous pressure sensitivity—where pressure on the pen tip generates physical displacement—current technologies face significant optical and algorithmic challenges.

[0011] 1. Zoom blur: The camera of a traditional photoelectric pen is fixed. When the pen tip is retracted by force, the object distance changes, causing the image to blur instantly and resulting in loss of optical flow tracking.

[0012] 2. Axial pseudo-displacement interference: Even when using a large depth-of-field lens to solve the blur problem, the axial movement of the pen tip will still produce radial perspective contraction on the image sensor. Traditional algorithms will misinterpret this perspective distortion as a slight movement of the plane, causing the cursor to jitter when the user clicks or presses hard.

[0013] 3. Sensitivity nonlinear drift: Pen tip retraction will reduce the imaging magnification, so that the same physical movement distance corresponds to different pixel displacements under different pressures, resulting in inconsistent writing feel.

[0014] In summary, there is an urgent need to provide a solution to eliminate zoom blur and pseudo-displacement interference in macro imaging. Summary of the Invention

[0015] To address the shortcomings of existing technologies, the present invention aims to provide an intelligent dual-mode all-media digital input device and control method.

[0016] According to one aspect of this application, an intelligent dual-mode all-media digital input device is disclosed, including a pen body, a conductive textured ball assembly, an image acquisition and transmission unit, a capacitive signal enhancement unit, a pressure detection unit, and a microcontroller.

[0017] The conductive textured ball assembly is located at the front end of the pen body and includes microspheres. The surface of the microspheres is covered with an optical diffuse reflection texture for optical flow tracing and has conductive properties.

[0018] The image acquisition and transmission unit is located inside the pen body, with its optical axis pointing towards the surface of the microsphere, and is configured to acquire texture images of the surface of the microsphere;

[0019] The capacitor signal enhancement unit is electrically connected to the microsphere and is configured to load an enhanced capacitive coupling signal onto the microsphere;

[0020] The pressure detection unit refers to a sensing structure used to detect the axial displacement of the conductive textured ball assembly and output a pressure signal, configured to detect the axial pressure on the conductive textured ball assembly.

[0021] The independent input mode refers to the working mode in which displacement data is acquired by the image acquisition and transmission unit and combined with pressure signals to generate input commands when no screen electrical characteristic signal is detected.

[0022] The preload adjustment mechanism refers to a mechanical structure used to adjust the initial compression of the elastic reset member to change the pressure trigger threshold.

[0023] The microcontroller is configured to control the device to switch between screen interaction mode and independent input mode. In the screen interaction mode, the microcontroller activates the capacitive signal enhancement unit and outputs active capacitive touch signal to the external touch screen through the microsphere.

[0024] In the independent input mode, the microcontroller activates the image acquisition and transmission unit to acquire two-dimensional optical flow displacement data on the surface of the microsphere, and combines it with the axial pressure data output by the pressure detection unit to generate a multi-dimensional input command that includes spatial movement and pressing states.

[0025] In some embodiments, the conductive textured ball assembly and the image acquisition and transmission unit are assembled into a floating sensing module;

[0026] The floating sensing module is configured to be axially displaced relative to the pen body and held in its initial position by an elastic reset member.

[0027] The imaging input end of the image acquisition and transmission unit moves synchronously axially with the microsphere, so that the relative imaging object distance between the imaging input end and the surface of the microsphere remains constant during the axial displacement of the floating sensing module.

[0028] The pressure detection unit is configured to determine the axial pressure on the conductive textured ball assembly by detecting the axial displacement of the floating sensing module.

[0029] In some embodiments, the device further includes a media recognition unit and a human-machine interface, wherein the media recognition unit is based on a microsphere and a touch circuit;

[0030] The microcontroller determines the medium type by detecting the carrier signal transmitted on the contact surface of the microsphere. When a threshold screen carrier signal is detected, it switches to screen interaction mode; otherwise, it switches to independent input mode.

[0031] or,

[0032] The microcontroller switches modes in response to user commands received from the human-computer interaction interface.

[0033] In some embodiments, the capacitor signal enhancement unit includes a high-voltage drive circuit;

[0034] The high-voltage drive circuit is configured to output an excitation signal with a peak-to-peak value of not less than 10V to compensate for insufficient capacitive coupling caused by the small contact area of ​​the microsphere.

[0035] In some embodiments, the pressure detection unit is a displacement detection type pressure sensing structure, selected from at least one of an optical displacement modulation structure, an electromagnetic displacement detection structure, or a capacitive displacement detection structure, and is configured to determine the pressure signal by detecting the axial displacement of the floating sensing module relative to the pen body.

[0036] When the optical displacement modulation structure is used, the floating sensing module is provided with an optical modulation feature, and a photodetector is provided at a relative position inside the pen body; the optical modulation feature is configured as a mark with changes in optical properties; the photodetector is configured to detect changes in light flux or pulse count caused by the axial displacement of the floating sensing module, and output the corresponding pressure signal.

[0037] In some embodiments, the conductive textured ball assembly further includes a ball base, the microspheres being rotatably embedded inside the ball base, a portion of the microspheres being exposed through a front opening of the ball base, and the diameter of the microspheres being configured to be no greater than 16.0 mm;

[0038] The outer sidewall of the ball seat is made of insulating material to block the electrical signal on the microsphere from leaking out laterally, allowing the electrical signal to radiate outward only from the front opening;

[0039] The ball seat body is provided with elastic conductive contacts, which are configured to maintain dynamic contact with the micro sphere to transmit external electrical signals or capacitively coupled signals.

[0040] The ball seat body is also provided with a friction support structure, which includes multiple micro support beads or support surfaces made of self-lubricating material, configured to form damped sliding contact or omnidirectional rolling contact with the microsphere; so that the static friction between the microsphere and the external contact medium is greater than the sum of the overall rolling friction and sliding friction resistance experienced by the microsphere in the ball seat body, so as to ensure that the microsphere can roll smoothly on the smooth touch screen surface without slipping.

[0041] In some embodiments, the device further includes an inertial measurement unit for real-time detection of the rotational angularity of the pen body about the central axis of the pen.

[0042] The microcontroller is configured to construct a rotation compensation matrix based on the detected rotation angle, and to perform coordinate system transformation on the two-dimensional coordinate data output by the image acquisition and transmission unit to correct the input trajectory direction deviation caused by the rotation of the grip posture, so that the coordinate system of the output trajectory always remains aligned with the coordinate system of the contact plane.

[0043] In some embodiments, the microcontroller is configured to perform multi-source data fusion in the independent input mode;

[0044] The microcontroller uses the pressure signal output by the pressure detection unit as a zero-speed correction gate signal. When the detected pressure signal is higher than a preset threshold, it determines that the state is in contact. It uses displacement data provided by the optical flow algorithm to constrain and correct the integral error of the inertial measurement unit. When the detected pressure signal is lower than a preset threshold, it determines that the state is in suspension. The microcontroller mainly calculates the spatial movement trajectory of the pen tip based on the data from the inertial measurement unit.

[0045] In some embodiments, the microcontroller is configured with a spatial interaction control mode;

[0046] In this mode, the device uses the pressure signal provided by the pressure detection unit as a continuously changing intensity control parameter, and uses the spatial attitude data provided by the inertial measurement unit as an orientation control parameter.

[0047] The microcontroller is configured to continuously monitor the spatial posture of the pen body, and activate the spatial interaction control mode only when the pen posture is detected to conform to the preset non-writing control posture for a preset duration.

[0048] In this mode, the device responds to the axial pressure signal applied to the microsphere. When the pressure signal exceeds a preset trigger threshold, the pressure amplitude is mapped to a multi-dimensional control command for the controlled object. At the same time, the tilt angle or three-dimensional orientation of the pen body is calculated in real time and mapped to the movement direction of the controlled object or the movement trajectory of the navigation cursor. This constructs a three-dimensional interactive mechanism based on adjusting the intensity of the press depth and defining the direction of the spatial posture. The tilt angle of the pen body is obtained in real time based on the inertial measurement unit.

[0049] In some embodiments, the device further includes a preload adjustment mechanism for changing the initial compression of the elastic reset member to adjust the starting pressure threshold for the floating sensing module to generate displacement.

[0050] According to another aspect of this application, a control method for the intelligent dual-mode all-media digital input device as described above is also disclosed, comprising the following steps:

[0051] Step S1: Detect the current mode switching trigger source, wherein the mode switching trigger source includes an active trigger command or an automatic media identification result;

[0052] Step S2: If the current mode switching trigger source is detected to be an active trigger command, then switch to the command trigger mode of the active trigger command in response to the active trigger command, wherein the command trigger mode is a screen interaction mode or an independent input mode;

[0053] Step S3: If the current mode switching trigger source is detected as an automatic media identification result, then the following sub-steps are performed based on the automatic media identification result:

[0054] Sub-step S3.1: Continuously monitor the electrical and pressure signals of the contact surface using the conductive textured ball assembly;

[0055] Sub-step S3.2: Determine whether a screen electrical characteristic signal of a preset frequency has been detected;

[0056] Sub-step S3.3: If a screen electrical characteristic signal is detected, it is determined to be a screen interaction mode, and a capacitive touch signal is output;

[0057] Sub-step S3.4: If no screen electrical feature signal is detected, and the detected pressure signal is higher than the preset threshold, then it is determined to be a contact input state in independent input mode, and the image acquisition and transmission unit is started to perform texture optical flow tracking and generate motion trajectory;

[0058] Sub-step S3.5: If no screen electrical characteristic signal is detected and the pressure signal is lower than the preset threshold, it is determined to be a floating state of independent input mode, and cursor control data is generated or sleep mode is entered.

[0059] In some embodiments, after entering the screen interaction mode in sub-step S3.3 or step S2, the image acquisition and transmission unit is turned off according to a preset configuration, and only the touch coordinates fed back by the external screen are used as positioning data.

[0060] or,

[0061] Keep the image acquisition and transmission unit turned on, use the optical flow algorithm to obtain the two-dimensional motion vector of the microsphere, and perform auxiliary verification or interpolation fusion on the touch coordinates fed back by the external screen to generate high-frequency positioning data to fill the screen touch sampling gap.

[0062] In some embodiments, the method further includes a trajectory accuracy compensation step, which is executed by the microcontroller to correct imaging distortion and sensitivity drift caused by the axial motion of the microsphere, and includes the following steps:

[0063] Step 1: Real-time acquisition of the axial displacement of the conductive textured ball assembly or the corresponding pressure sensing value;

[0064] Step 2: Based on the axial displacement and the imaging optical path geometry, calculate the current imaging magnification change coefficient in real time.

[0065] Step 3: Using the aforementioned variation coefficient, perform reverse scaling compensation on the original two-dimensional pixel displacement output by the optical flow algorithm to eliminate the nonlinear attenuation of the number of dots per inch caused by the sphere's retreat.

[0066] Step 4: Monitor the characteristics of the optical flow vector field. When a step change in the axial displacement is detected and the optical flow vector exhibits radial contraction or expansion characteristics centered on the optical axis, it is determined to be axial interference generated by the click action. The two-dimensional displacement output corresponding to the axial interference is suppressed or filtered.

[0067] The present invention includes, but is not limited to, the following beneficial effects: (1) This solution uses a conductive textured ball as both a capacitive sensing probe and an optical tracking texture source, and works with a media recognition unit to intelligently detect the screen carrier signal. A single pen can work on any surface such as a capacitive touch screen, ordinary paper, or a desktop, solving the problems of traditional active capacitive pens only being able to write on screens and traditional dot matrix pens / photoelectric pens only being able to write on paper or relying on special media, which are characterized by limited functionality and fragmented scenarios. This provides users with versatility and convenience. (2) This solution rigidly connects the image sensor to the microsphere and moves synchronously, ensuring that the imaging distance remains constant under any writing pressure. This eliminates the zoom blur and axial pseudo-displacement interference caused by the retraction of the pen tip in traditional fixed camera solutions. (3) This solution provides hardware support for continuous, linear, and high-precision pressure-sensitive writing; (4) The rotational posture compensation algorithm based on the inertial measurement unit allows users to maintain the pen posture without having to consciously maintain the pen posture. The screen trajectory direction is always consistent with the hand movement. The zero-speed correction algorithm based on pressure gating, combined with the pressure signal and the inertial measurement unit, effectively suppresses the trajectory drift when writing on ordinary media, and realizes high-quality paper-screen synchronization and offline notes; (5) Through the spatial interaction control mode, the pen is extended from a two-dimensional writing tool to a three-dimensional spatial controller, such as an air mouse, PPT page turner, and 3D modeling controller. By using posture control direction and pressure control intensity, a new interactive scenario is created, which enhances the added value and premium of the product. Attached Figure Description

[0068] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0069] Figure 1 This is a schematic diagram of the functional modules of the hardware system according to an embodiment of the present invention;

[0070] Figure 2 This is a schematic diagram of the device structure from one angle according to an embodiment of the present invention;

[0071] Figure 3 This is a schematic diagram of the device structure from another angle according to an embodiment of the present invention;

[0072] Figure 4 This is a schematic diagram of the device structure from another angle according to an embodiment of the present invention;

[0073] Figure 5This is a schematic diagram of the device structure from another angle according to an embodiment of the present invention;

[0074] Figure 6 This is a schematic diagram of the device structure from another angle according to an embodiment of the present invention;

[0075] Figure 7 This is a schematic diagram of the auxiliary radiation electrode according to an embodiment of this application;

[0076] Figure 8 This is a flowchart of the control method according to an embodiment of this application;

[0077] Figure 9 This is a schematic diagram of the control logic of an embodiment of this application;

[0078] In the diagram, 10-pen tip assembly, 11-microsphere, 12-ball seat, 20-pen barrel body, 21-physical orientation feature, 22-moving electrode plate, 23-fixed electrode plate, 30-hollow sliding assembly, 31-image acquisition and transmission unit, 311-fiber optic bundle, 312-image sensor, 313-cable, 32-optical modulation feature section, 40-elastic reset component, 41-preload adjustment mechanism, 50-photodetector, 60-capacitive signal enhancement unit, 61-auxiliary radiation electrode, 70-microcontroller, 80-main control circuit board, 90-magnetic component, 91-electromagnetic sensitive component. Detailed Implementation

[0079] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0080] See Figures 2 to 6 This application discloses an intelligent dual-mode all-media digital input device, including a pen body 20, a conductive texture ball assembly (also known as a pen tip assembly), an image acquisition and transmission unit 31, a capacitive signal enhancement unit 60, a pressure detection unit, and a microcontroller 70.

[0081] The conductive textured ball assembly is located at the front end of the pen body 20 and includes a microsphere 11. The surface of the microsphere 11 is covered with an optical diffuse reflection texture for optical flow tracing and has conductive properties.

[0082] The image acquisition and transmission unit 31 is located inside the pen body 20, with its optical axis pointing to the surface of the microsphere 11, and is configured to acquire texture images of the surface of the microsphere 11.

[0083] The capacitor signal enhancement unit 60 is electrically connected to the microsphere 11 and is configured to load an enhanced capacitive coupling signal onto the microsphere 11;

[0084] The pressure detection unit is configured to detect the axial pressure on the conductive textured ball assembly;

[0085] The microcontroller 70 is configured to control the device to switch between screen interaction mode and independent input mode. In screen interaction mode, it activates the capacitive signal enhancement unit 60 and outputs active capacitive touch signal to the external touch screen through the microsphere 11. In independent input mode, it activates the image acquisition and transmission unit 31 and acquires the two-dimensional optical flow displacement data of the surface of the microsphere. Combined with the axial pressure data output by the pressure detection unit, it generates a multi-dimensional input command that includes spatial movement and pressing states.

[0086] Understandably, by using a conductive texture ball as both a capacitive sensing probe and an optically tracked texture source, a single pen can work on any surface, such as a capacitive touchscreen, ordinary paper, or a desktop. This solves the problems of traditional active capacitive pens being limited to writing on screens and traditional dot matrix pens / photoelectric pens being limited to writing on paper or relying on special media, resulting in limited functionality and fragmented application scenarios. This provides users with versatility and convenience.

[0087] In one example, the conductive textured ball assembly and the image acquisition and transmission unit 31 are assembled into a floating sensing module. The floating sensing module is configured to be axially displaced relative to the pen body 20 and held in its initial position by an elastic reset member 40. The imaging input end of the image acquisition and transmission unit 31 moves axially synchronously with the microsphere 11, so that the relative imaging object distance between the imaging input end and the surface of the microsphere 11 remains constant during the axial displacement of the floating sensing module. The pressure detection unit is configured to determine the axial pressure on the conductive textured ball assembly by detecting the axial displacement of the floating sensing module.

[0088] Specifically, the image sensor 312 is rigidly connected to the microsphere 11 and moves synchronously, ensuring that the imaging distance remains constant under any writing pressure. This eliminates the zoom blur and axial pseudo-displacement interference caused by the retraction of the pen tip in traditional fixed camera solutions, providing hardware assurance for continuous, linear, and high-precision pressure-sensitive writing.

[0089] Furthermore, the device also includes a media identification unit and a human-machine interface. The media identification unit is based on a microsphere 11 and a touch circuit. The microcontroller 70 determines the media type by detecting the carrier signal transmitted on the contact surface of the microsphere 11. When a threshold screen carrier signal is detected, it switches to the screen interaction mode; otherwise, it switches to the independent input mode. Alternatively, the microcontroller 70 switches modes in response to user commands received by the human-machine interface.

[0090] In some examples, the capacitive signal enhancement unit 60 includes a high-voltage driving circuit configured to output an excitation signal with a peak-to-peak value of not less than 10V to compensate for insufficient capacitive coupling caused by the small contact area of ​​the microsphere 11. An auxiliary radiation electrode 61 is also provided around the conductive textured ball assembly. This auxiliary radiation electrode 61 synchronously transmits the coupling signal with the microsphere 11, configured to expand the touch area through the edge electric field effect without touching the screen. The pressure detection unit adopts an optical displacement modulation structure. An optical modulation feature 32 is provided on the floating sensing module, and a photodetector 50 is provided at a relative position within the pen body 20. The optical modulation feature 32 is configured as a mark with changes in optical properties, and the photodetector 50 is configured to detect changes in luminous flux or pulse counting caused by the axial displacement of the floating sensing module and output the corresponding pressure signal.

[0091] Furthermore, the conductive textured ball assembly also includes a ball base 12, in which a microsphere 11 is rotatably embedded. A portion of the microsphere 11 is exposed through the front opening of the ball base 12, and the diameter of the microsphere 11 is configured to be no greater than 16.0 mm. The outer sidewall of the ball base 12 is configured with an insulating material to block the electrical signal on the microsphere 11 from leaking out laterally, allowing the electrical signal to radiate outward only from the front opening. The ball base 12 is provided with elastic conductive contacts, configured to maintain dynamic contact with the microsphere 11 to transmit external electrical signals or capacitively coupled signals.

[0092] Understandably, the device utilizes the capacitor signal enhancement unit 60, such as a high-voltage drive circuit, to apply a high-energy capacitor signal to a microsphere 11 with a diameter of no more than 16.0 mm, solving the problem of touch recognition under small contact areas. Simultaneously, it uses optical flow technology to capture the diffuse reflection texture of the sphere's surface, enabling trajectory recording and hover motion tracking on any medium surface. Controlled by the microcontroller 70, the device functions as both an active capacitive pen and a high-precision optical flow mouse.

[0093] Furthermore, the ball seat 12 is also provided with a friction support structure inside. The friction support structure includes multiple micro support beads or a support surface made of self-lubricating material, which is configured to form a damped sliding contact or omnidirectional rolling contact with the micro ball 11, so that the static friction between the micro ball 11 and the external contact medium is greater than the sum of the rolling friction and sliding friction resistance between the micro ball 11 and the ball seat 12, so as to ensure that the micro ball can roll smoothly on the smooth touch screen surface without slipping.

[0094] Furthermore, the device also includes an inertial measurement unit, which is used to detect the rotational angle of the pen body 20 around the central axis of the pen in real time;

[0095] The microcontroller 70 is configured to construct a rotation compensation matrix based on the detected rotation angle, and to perform coordinate system transformation on the two-dimensional coordinate data output by the image acquisition and transmission unit 31 to correct the input trajectory direction deviation caused by the rotation of the grip posture, so that the coordinate system of the output trajectory always remains aligned with the coordinate system of the contact plane.

[0096] Specifically, the microcontroller 70 is configured to perform multi-source data fusion in independent input mode, using the pressure signal output by the pressure detection unit as the zero-speed correction gating signal. When the detected pressure signal is higher than a preset threshold, it is determined to be in contact state. The displacement data provided by the optical flow algorithm is used to constrain and correct the integral error of the inertial measurement unit. When the detected pressure signal is lower than a preset threshold, it is determined to be in suspension state. The spatial movement trajectory of the pen tip is mainly calculated based on the data of the inertial measurement unit.

[0097] Furthermore, the microcontroller 70 is equipped with a spatial interaction control mode;

[0098] In this mode, the device uses the pressure signal provided by the pressure detection unit as a continuously changing intensity control parameter, and the spatial attitude data provided by the inertial measurement unit as the direction control parameter; furthermore, it continuously monitors the spatial attitude of the pen body 20, and only activates the spatial interactive control mode when the pen attitude is detected to conform to the preset non-writing control attitude for a preset duration; or,

[0099] In this mode, the device responds to the axial pressure signal applied to the microsphere 11. When the pressure signal exceeds a preset trigger threshold, the pressure amplitude is mapped to a multi-dimensional control command for the controlled object. At the same time, the tilt angle or three-dimensional orientation of the pen body 20 is calculated in real time and mapped to the movement direction of the controlled object or the movement trajectory of the navigation cursor. This constructs a three-dimensional interactive mechanism based on adjusting the intensity of the press depth and defining the direction of the spatial posture. The tilt angle of the pen body 20 is obtained in real time based on the inertial measurement unit.

[0100] Understandably, the compensation algorithm in this example, based on optical geometry, uses real-time acquired Z-axis pressure / displacement data to dynamically calculate the magnification coefficient, performs reverse scaling compensation on the X / Y axis coordinates of the optical flow output, and filters out pseudo-displacement signals generated by click actions, ensuring the linearity and stability of the writing feel. Furthermore, the device combines an inertial measurement unit (IMU) and a pressure sensor to construct a spatial interaction mode. In a suspended state, the cursor direction is controlled using an attitude pod, and the intensity of actions such as page turning speed and scaling ratio are controlled by the pressure applied to the ball head, achieving precise control in three-dimensional space.

[0101] Furthermore, the device is also equipped with a preload adjustment mechanism, which is used to change the initial compression of the elastic reset member 40 to adjust the starting pressure threshold for the floating sensing module to generate displacement.

[0102] Furthermore, to better understand this technical solution, the following embodiments are provided for specific explanation:

[0103] Continue reading Figure 1 The hardware system of this all-media digital input device is based on a microcontroller 70 unit, and the functional modules of the hardware system are configured as follows:

[0104] The sensing input end includes an image acquisition and transmission unit 31 for capturing surface texture movement, a pressure detection unit for detecting axial displacement, a medium identification unit for detecting the electrical characteristics of the contact surface, a human-machine interface for receiving instructions, and an inertial measurement unit (IMU) for acquiring spatial attitude in real time.

[0105] The drive output includes a capacitor signal enhancement unit 60 controlled by a microcontroller 70 that emits high-voltage excitation to an external screen, and a haptic feedback execution unit for providing the sensation of pressing or writing paragraphs.

[0106] Peripheral support circuitry includes a wireless communication unit for establishing data connections with external devices, such as tablets, and a power management unit for power distribution to all modules of the device. The wireless communication unit may be a Bluetooth or Wi-Fi module.

[0107] In a preferred embodiment of the present invention, although an image acquisition and transmission unit is primarily used to capture the diffuse reflection texture of the sphere's surface to achieve trajectory tracking, those skilled in the art should understand that, as an equivalent extension of the electromechanical integrated architecture of the present invention, this displacement capture unit can also be replaced by a three-dimensional rolling detection array based on non-optical principles. For example, the microsphere can be configured as a multi-pole magnetic sphere with non-uniformly distributed magnetic poles on its surface or inside, while a 3D Hall sensor array or magnetoresistive sensor network is configured inside the pen body to generate motion trajectory data by calculating the temporal changes of the magnetic field vector. Such schemes based on the equivalent replacement of optical flow sensors with magnetic fields, as long as they are combined with the capacitive signal enhancement unit and control logic described in the present invention, do not depart from the core protection concept of the present invention.

[0108] This example provides two mechanical implementations to suit different manufacturing processes and cost requirements.

[0109] Example 1: Front-facing camera module and micro coaxial cable transmission

[0110] This implementation aims to solve the technical problem that when traditional photoelectric pens are subjected to writing force, the slight displacement of the pen tip causes a change in the imaging focal length, which in turn leads to the failure of optical flow tracing. It is suitable for professional application scenarios that require high imaging quality and continuous high-precision pressure-sensitive writing.

[0111] Continue reading Figure 2 The floating sensing module of this device adopts a split-type follower structure. Mechanically, the floating sensing module includes a hollow sliding assembly 30 built into the pen body 20 and capable of sliding axially, and a detachable pen tip assembly 10 detachably connected to its front end. In terms of imaging structure, unlike the prior art design where the image sensor 312 is fixed to the pen body shell, the image acquisition and transmission unit 31 in this embodiment includes a miniature complementary image sensor 312. This image sensor 312 is not fixed but directly encapsulated inside the front end of the movable hollow sliding assembly 30. The optical axis of the lens of this image sensor 312 coincides with the axis of the pen body 20 and maintains a fixed physical distance from the miniature sphere 11 at the front end.

[0112] To overcome the insufficient depth of field and perspective distortion caused by the high curvature of the microsphere (diameter ≤ 16.0 mm), the image acquisition and transmission unit 31 is equipped with a micro-narrow field-of-view lens group, which strictly limits its effective field of view to a small area of ​​an approximate plane near the vertex of the microsphere 11, thereby ensuring that the texture features in this area are always within the clear depth of field and the motion vector is approximately linearly translated.

[0113] In this specification, the surface of the microsphere 11 is provided with an optical texture to achieve optical flow tracing. In a preferred embodiment, to ensure compatibility with capacitive touchscreens, the microsphere 11 is made of a conductive material and is also referred to as a conductive textured sphere. It should be understood that, in the following description, unless otherwise specified, the microsphere 11 generally refers to a preferred form with conductive properties, but the possibility of using non-conductive materials in non-screen applications is not excluded.

[0114] For signal transmission and displacement compensation, the signal output terminal of the image sensor 312 is connected to a bundle of extremely fine coaxial cables 313, or a flexible printed circuit board. One end of the cable 313 is soldered to the following image sensor 312, and the other end is connected to the main control circuit board 80 fixed to the rear of the pen body 20. To accommodate frequent displacement during writing, the cable 313 is pre-reserved in a U-shape or spiral shape inside the pen body 20. This flexible connection structure allows the sensor to float freely inside the pen without breaking the circuit or causing signal interference.

[0115] When the user applies writing pressure, causing the microsphere 11 to push the hollow sliding component 30 to overcome the resistance of the return spring and generate an axial backward displacement of 0.1 mm to 1 mm to detect pressure, the internally encapsulated image sensor 312 simultaneously and equally retracts. This dynamic-static coupling design ensures that the imaging object distance between the sensor lens and the surface texture of the sphere remains constant regardless of how drastic the external writing pressure changes. This eliminates image blurring and optical flow calculation errors caused by force-induced zoom in traditional photoelectric pens, guaranteeing the continuity and stability of trajectory tracking under any pressure level. At this time, the micro-coaxial cable 313 absorbs the above displacement using its flexible bending characteristics, ensuring the reliability of high-speed image signal transmission.

[0116] Example 2: Fiber Optic Image Guide and Opto-Isolation Structure

[0117] This embodiment is applicable to application scenarios that require extreme lightweight design and resistance to strong electromagnetic interference.

[0118] Continue reading Figure 3 The difference in structure between this embodiment and Embodiment 1 lies in the image acquisition method. The image sensor 312 is not mounted on the floating component but is soldered onto the stationary main control circuit board 80. The hollow sliding assembly 30 serves as the carrier of the image acquisition and transmission unit 31, and internally encapsulates a bundle of highly flexible optical fibers 311. The front end of the fiber bundle 311 serves as the acquisition end, maintaining a fixed focal length with the sphere; the rear end of the fiber bundle 311 is suspended and aligned with the image sensor 312 on the main control circuit board 80. When the floating module is subjected to force and displacement, the fiber bundle 311 retracts as a whole. Because the rear end of the fiber bundle 311 is non-contact optically coupled to the onboard sensor, and the optical fiber itself is elastic, this structure completely eliminates the electrical connection of moving parts, physically isolating the risk of static electricity and wear.

[0119] In this embodiment, the image acquisition and transmission unit 31 includes a flexible image transmission fiber bundle 311 and an image sensor 312 located on the motherboard. The incident end face of the fiber bundle 311 constitutes the imaging input end. Although the image sensor 312 itself is fixed, the front end of the fiber bundle 311, i.e., the imaging input end, moves synchronously with the sphere, thereby satisfying the requirement that the imaging input end moves synchronously with the sphere.

[0120] Furthermore, for the pressure detection scheme implementation, this scheme provides three optional detection schemes based on the principle of displacement-pressure conversion.

[0121] Example 3: Electromagnetic pressure detection scheme based on Hall effect or inductive sensing

[0122] This embodiment is mainly applied to industrial-grade products that require high dust and water resistance or need to be used in oily environments.

[0123] Continue reading Figure 4 In terms of mechanical structure, the hollow sliding component 30 of the floating sensing module has a groove on its side wall, and a magnetic element 90 is fixed in the groove. This element can be a permanent magnet or a metal conductor. An electromagnetic sensing element 91 is mounted on the main control circuit board 80 inside the pen body 20 at a corresponding position. When Hall effect detection is used, initially, the permanent magnet and the linear Hall sensor on the circuit board maintain a preset initial distance. When writing force causes the sliding component to move backward, the distance between them decreases, and the magnetic flux density passing through the Hall element increases non-linearly. The Hall sensor then outputs a corresponding analog voltage signal. The microcontroller 70 uses an internally stored lookup table or polynomial fitting algorithm to calibrate the non-linear voltage signal in real time to a standard linear pressure value of 0 to 1024 levels. When inductive detection is used, the sensing element on the circuit board is replaced with a planar spiral coil. When the metal conductor on the sliding component approaches the coil, eddy currents are generated on the coil surface, causing a slight change in inductance. The displacement value can be calculated with high precision by detecting the shift in the resonant frequency. The advantage of this embodiment is that it is non-contact measurement, there is no mechanical wear, and it is not sensitive to ambient light and oil stains.

[0124] Example 4: Optical pressure detection scheme based on optical flux modulation

[0125] This embodiment is a preferred high-precision solution, mainly used in scenarios such as tablet computer drawing where linearity requirements are extremely high and resistance to magnetic interference is needed, such as with a pen that uses magnetic charging.

[0126] Continue reading Figure 5 An optical modulation feature 32 is provided on the side of the floating sensing module. This optical modulation feature 32 is a specially designed grayscale scale, whose surface optical reflectivity linearly changes from 10% to 90% along the axial direction. Inside the pen body 20, at a corresponding position, is a set of reflective photodetectors 50 composed of an infrared emitting diode and a photodiode. When the user applies pressure to retract the module, the position of the light spot illuminated by the photodetector 50 on the grayscale scale changes. Because the reflectivity of the scale changes in a gradient, the intensity of the reflected light received by the photodiode also changes continuously and linearly. The microcontroller 70 acquires this current change through an analog-to-digital converter interface to obtain a very high-resolution pressure reading. The advantage of this embodiment is that the optical signal is naturally immune to electromagnetic interference, ensuring writing consistency.

[0127] Example 5: Mutual Capacitance Pressure Detection Scheme Based on Electrostatic Shielding

[0128] This embodiment is a highly integrated and low-cost alternative solution that addresses the problem of capacitive sensors being easily interfered with by high-voltage signals from touchscreens.

[0129] Continue reading Figure 6In terms of structural design, a moving electrode plate 22 is located at the end of the floating sensing module, and a fixed electrode plate 23 is located on the inner wall of the pen body 20 at a relatively opposite position. The two are coaxially aligned or laterally overlapped, forming a variable capacitor for detecting displacement. To achieve high-resolution pressure detection of 4096 levels or higher, the moving electrode plate 22 and the fixed electrode plate 23 are connected to a dedicated capacitance-to-digital converter (CDC) or a high-precision analog front-end (AFE). This front-end chip converts weak capacitance changes into high-bit-width digital signals, such as 16-bit or 24-bit, and transmits them to the main control MCU via a bus, thereby overcoming the problem of insufficient accuracy of the MCU's built-in touch module.

[0130] Specifically, in this structure, to ensure the stable operation of the mutual capacitance pressure detection module in the high-voltage driven screen interaction mode, this embodiment adopts omnidirectional shielding anti-interference measures: a layer of grounded flexible conductive cloth or copper foil is wrapped around the moving electrode plate 22 and the fixed electrode plate 23 as a reference potential shield. This shield forms a Faraday cage, effectively bypassing electromagnetic noise radiated from the external space and high-frequency electrical signals transmitted by the conductive textured sphere to the ground, thereby protecting the weak internal capacitance displacement measurement electric field from being submerged and ensuring the purity of the pressure reading.

[0131] The pressure detection principle under this structure is as follows:

[0132] The device inversely calculates the pressure by detecting the capacitance change between the moving plate 22 and the fixed plate 23 and combining it with the formula for a parallel plate capacitor.

[0133] The formula for a parallel-plate capacitor is as follows:

[0134]

[0135] In the formula, This is the capacitance value. Where is the dielectric constant. The relative area of ​​the two plates. The distance between the two plates is denoted as .

[0136] When the pen tip is subjected to a force F, the floating sensor module compresses the return spring, causing axial displacement. This mechanical displacement corresponds to an axial displacement in the optical coordinate system described later. .

[0137] If the structure is designed so that the moving electrode 22 is closer to the fixed electrode 23, then the spacing Decrease, capacitance Increase. Pressure and capacitance show a non-linear positive correlation.

[0138] If the structure is designed such that the moving electrode plate 22 is inserted inside the fixed electrode plate 23, then the displacement... Directly change the overlapping area The change in capacitance at this time With displacement A linear relationship exists:

[0139] ;

[0140] Combining Hooke's Law Thus, a linear relationship between pressure and capacitance change can be obtained:

[0141]

[0142] in This is the proportionality coefficient of capacitance change. This refers to the spring constant of the return spring. The microcontroller 70 measures the change in capacitance. This allows for the precise calculation of the current pressure value F. Here, the axial displacement generated by the floating sensor module is denoted as in the optical coordinate system. In mechanical logic, this is denoted as the spring compression. Numerically, the two are equal, that is... .

[0143] Furthermore, this solution also provides a low-cost directional grip structure embodiment:

[0144] Example 6: Low-cost directional grip structure

[0145] This embodiment aims to solve the coordinate system rotation problem during photoelectric pen writing through structural optimization without increasing the cost of electronic components. It is suitable for entry-level or cost-sensitive product models. (Continue reading...) Figure 3 A small protrusion is added to the gripping area of ​​the pen body 20 as a physical orientation feature 21. Other types of physical features can also be defined, such as rounded triangles, ellipses, or D-shaped structures with cut surfaces. This non-cylindrical physical feature naturally guides the fingers to conform to a specific plane when the user picks up the pen, thereby forcing the user to hold the pen at a preset angle and restricting the pen's free rotation around its axis.

[0146] During the production and assembly process, the manufacturer can calibrate and fix the imaging coordinate system of the internal image acquisition and transmission unit 31 with the positioning plane on the outside of the pen barrel. This ensures that when the user writes, the sensor's coordinate system is naturally aligned with the horizontal line of the paper or desktop. Even without an inertial measurement unit and its complex rotation compensation algorithm, the cursor movement direction on the screen can accurately follow the actual hand movement direction without skewing. This physically oriented design allows low-cost hardware to achieve a professional-grade, consistent writing experience.

[0147] Furthermore, this solution also discloses a control method for the aforementioned intelligent dual-mode all-media digital input device, such as... Figure 8 As shown, it includes the following steps:

[0148] Step S1: Detect the current mode switching trigger source, which may include active trigger commands or automatic media identification results;

[0149] Step S2: If the current mode switching trigger source is detected to be an active trigger command, then switch to the command trigger mode of the active trigger command in response to the active trigger command, wherein the command trigger mode is either screen interaction mode or independent input mode;

[0150] Step S3: If the current mode switching trigger source is detected as the automatic media identification result, then execute the sub-step based on the automatic media identification result:

[0151] Sub-step S3.1: Continuously monitor the electrical and pressure signals of the contact surface using the conductive textured ball assembly;

[0152] Sub-step S3.2: Determine whether a screen electrical characteristic signal of a preset frequency has been detected;

[0153] Sub-step S3.3: If a screen electrical characteristic signal is detected, it is determined to be a screen interaction mode, and a capacitive touch signal is output;

[0154] Sub-step S3.4: If no screen electrical feature signal is detected, and the detected pressure signal is higher than the preset threshold, then it is determined to be a contact input state in independent input mode, and the image acquisition and transmission unit is started to perform texture optical flow tracking and generate motion trajectory.

[0155] Sub-step S3.5: If no screen electrical characteristic signal is detected and the pressure signal is lower than the preset threshold, it is determined to be a floating state of independent input mode, and cursor control data is generated or sleep mode is entered.

[0156] In some embodiments, after entering the screen interaction mode in sub-step S3.3 or step S2, the image acquisition and transmission unit is turned off according to the preset configuration, and only the touch coordinates fed back by the external screen are used as positioning data.

[0157] or,

[0158] Keep the image acquisition and transmission unit on, use the optical flow algorithm to obtain the two-dimensional motion vector of the microsphere 11, and perform auxiliary verification or interpolation fusion on the touch coordinates fed back by the external screen to generate high-frequency positioning data to fill the screen touch sampling gap.

[0159] In some embodiments, the method further includes a trajectory accuracy compensation step, performed by the microcontroller 70, for correcting imaging distortion and sensitivity drift caused by the axial movement of the microsphere 11, including the following steps:

[0160] Step 1: Real-time acquisition of the axial displacement of the conductive textured ball component or the corresponding pressure sensing value.

[0161] Step 2: Based on the axial displacement and the geometric relationship of the imaging optical path, calculate the current imaging magnification change coefficient in real time;

[0162] Step 3: Using the variation coefficient, the original two-dimensional pixel displacement output by the optical flow algorithm is reverse-scaled and compensated to eliminate the non-linear attenuation of the number of dots per inch caused by the sphere's retreat.

[0163] Step 4: Monitor the characteristics of the optical flow vector field. When a step change in the axial displacement is detected and the optical flow vector exhibits radial contraction or expansion characteristics centered on the optical axis, it is determined to be axial interference generated by the click action. The two-dimensional displacement output corresponding to the axial interference is suppressed or filtered.

[0164] Specifically, to better understand the control method logic, the following examples will be used for detailed explanation:

[0165] Example 7: Rotational Attitude Compensation Algorithm Based on Inertial Measurement Unit

[0166] This embodiment details how to use a mathematical model to eliminate the influence of pen grip posture on the trajectory direction. To address the problem of deviation between the screen cursor movement direction and the actual hand movement direction caused by pen grip angle rotation, the processor within the device executes the following algorithm steps:

[0167] Step 1: Synchronous Data Acquisition from Multiple Sensors

[0168] The image acquisition and transmission unit 31 outputs the two-dimensional optical flow displacement vector of the sphere surface at a high frame rate, such as 120 frames per second. We label this as the original displacement vector. Meanwhile, the inertial measurement unit outputs the rotation angle of the pen barrel around its central axis at the same sampling frequency, denoted as θ.

[0169] Step 2: Construct the rotation matrix:

[0170] The processor constructs a two-dimensional rotation matrix R(θ) based on the read rotation angle θ. This matrix describes the coordinate rotation relationship in the two-dimensional plane, and its mathematical expression is as follows:

[0171] ;

[0172] in, The value of the cosine of the rotation angle. The value is the sine of the rotation angle.

[0173] Step 3: Real-time coordinate transformation:

[0174] The processor performs a matrix multiplication operation between the original displacement vector obtained in step one and the rotation matrix constructed in step two, thereby calculating the correction vector relative to the screen coordinate system, denoted as . The calculation formula is as follows:

[0175]

[0176] Step 4: Output and Results:

[0177] The processor will calculate the correction vector The data is then sent to an external display device. Through the algorithm described above, regardless of the user's pen grip angle, the screen cursor always moves upwards whenever the user pushes the pen upwards. This decouples the input coordinate system from the grip posture, ensuring an intuitive writing experience.

[0178] Example 8: Pressure Mapping and Interactive State Machine

[0179] This embodiment details how to achieve seamless switching between the hover cursor and the writing trajectory on a single pen tip through segmented control logic and a nonlinear mapping algorithm. The system control logic is as follows: Figure 8 As shown, it specifically includes the following four processing stages:

[0180] Phase 1: Dead Zone and Hover Cursor Logic

[0181] The system presets an activation threshold, denoted as . For example, if the value is set to correspond to 10 grams of force, the system monitors the current pressure value returned by the pressure detection unit in real time. .

[0182] When the current pressure value is detected Less than the activation threshold At this time, the system determines that the device is in cursor tracking mode. In this mode, the processor directly maps the optical flow displacement vector to the position coordinates of the screen cursor pointer, but does not send click or drawing commands. This allows the user to move the cursor on the screen to find the pen placement point, just like using a mouse.

[0183] Phase Two: Hysteresis Anti-shake Logic

[0184] To prevent false triggering or state transitions under critical pressure, the system incorporates Schmitt triggering logic. An activation threshold is set. and a release threshold And specify the activation threshold. Greater than the release threshold The writing state is triggered only when the pressure value rises above the activation threshold, and the hovering state is only returned when the pressure value falls below the release threshold. The mode switching judgment logic incorporates time window filtering to avoid frequent mode oscillations in weak signal edge environments.

[0185] Phase 3: Writing Responses and Nonlinear Mapping

[0186] Current pressure value Greater than or equal to the activation threshold When the system triggers the writing start event, the optical flow data is mapped to handwriting lines or drag paths. To simulate the feel of a real brush or fountain pen, the system outputs stroke thickness. Compared with the current pressure value The following non-linear mapping function applies between them:

[0187] ;

[0188] In the formula, This is the sensitivity coefficient. This is the gamma factor, which is usually between 1.5 and 2.0 and can be fine-tuned according to the pen tip material and size.

[0189] Phase 4: Generating Tactile Feedback

[0190] The pressure value is measured the instant the system switches from cursor tracking mode to writing mode. First time crossing the opening threshold At this time, the processor drives a linear vibration motor to generate a short vibration pulse lasting about 10 milliseconds. This feedback simulates the tactile feedback of a physical key being pressed, clearly indicating to the user that writing has been activated.

[0191] VI. Consumables and Media Identification Examples

[0192] Example 9: Intelligent pen tip assembly 10 and media recognition and multi-mode control

[0193] In this embodiment, the detachable pen tip assembly 10 is designed as a consumable material and is fixed to the front end of the floating sensing module by a threaded connection. The internal sphere is made of 2.5 mm diameter zirconia ceramic sphere and is doped with conductive carbon powder so that its volume resistivity meets the conductivity requirements. The surface of the sphere is laser-etched to form a pseudo-random speckle texture, thereby forming a microscopic diffuse reflection structure to enhance optical recognition features.

[0194] The device achieves intelligent identification of writing media and switching of working modes through the following logic:

[0195] Step 1: The electrodes in the pen grip area are connected to the internal circuit ground. When the hand holds the pen, the human body becomes the ground terminal of the system.

[0196] Step 2: The ball seat 12 inside the pen tip assembly 10 is provided with a conductive spring pin, which maintains electrical contact with the ball. The touch detection chip is connected to the spring pin to monitor the self-capacitance signal of the ball and the screen electrical characteristic signal transmitted from the contact surface in real time.

[0197] Step 3: If a specific scanning frequency screen electrical characteristic signal is detected emitted from the contact surface, it is determined to be in screen interaction mode. At this time, the processor reads the preset user configuration or power status and selects one of the following two strategies to execute:

[0198] Strategy 1 Low Power Mode: Suitable for scenarios with high battery life requirements. The system cuts off power to the internal fill light and image acquisition and transmission unit, only activating the capacitive communication function and pressure detection circuit. At this time, the device only sends pressure data, and positioning relies entirely on the capacitive touch layer of the external screen.

[0199] Strategy 2 High-Precision Fusion Mode: Suitable for drawing or high refresh rate scenarios. The system keeps the image acquisition and transmission unit and the fill light on, continuously outputting high frame rate data, such as sphere texture displacement data above 1000Hz. The processor performs Kalman filtering on this relative displacement data and the absolute coordinate data returned by the screen to fuse them, using the high-frequency characteristics of the optical flow data to fill the gaps in screen touch sampling, eliminating trajectory jitter and reducing writing latency.

[0200] Step 4: If no screen electrical characteristic signal is detected, but pressure signal and texture movement signal are detected, it is determined to be an independent input mode, such as on paper or a desktop. At this time, the system forces full-function operation, uses optical flow data to record the trajectory, and stores the data or transmits it to the main control device in real time.

[0201] Step 5: If there are no screen electrical characteristic signals, pressure or texture movement signals within the preset time, it is determined to be in a non-use state, and the system enters deep sleep mode to save power.

[0202] Example 10: Spatial Interactive Control Mode Based on Pressure Sensing and Attitude Fusion

[0203] This embodiment describes the spatial interaction function in detail, demonstrating how the device can be transformed from a single writing tool into a multi-dimensional spatial controller.

[0204] 1. Mode Activation and Status Determination:

[0205] The microcontroller 70 has a built-in attitude recognition algorithm that monitors the pen's attitude data output by the inertial measurement unit (IMU) in real time. This attitude data includes the pen's attitude parameters in three-dimensional space, specifically pitch, roll, and yaw. The attitude data is acquired in real time by the IMU, which includes a three-axis accelerometer and a three-axis gyroscope to collect raw motion signals. The microcontroller then performs attitude calculations based on these raw motion signals to obtain the pen's attitude data.

[0206] When the system detects that the pen is in a non-writing posture for more than a preset time, such as 0.5 seconds, it automatically enters the spatial interaction control mode. Non-writing postures include, but are not limited to, the inverted holding state: the pen tip faces the user and the pen tail points to the screen, similar to holding a remote control; the horizontal pointing state: the pen is roughly parallel to the ground and points to the controlled object; and specific gesture triggers: such as the user quickly swinging the pen twice in the air.

[0207] 2. Control logic mapping:

[0208] In the spatial interaction mode, the device establishes the following mapping relationship:

[0209] Orientation control channel attitude mapping: Using the angular velocity or angle change output by the inertial measurement unit, the motion direction of the external object is controlled. For example, tilting the pen to the left is mapped to moving the cursor to the left or rotating the model to the left.

[0210] Pressure sensitivity mapping for the intensity control channel: Utilizing the long-stroke linear pressure sensitivity characteristics of the floating sensing module. Users can directly press the pen tip with their fingers or place the pen tip against any supporting surface, such as the palm of their hand or the edge of a table, generating a continuous pressure signal from 0% to 100%. The system maps this pressure signal to the intensity value of the control parameter. This embodiment fully utilizes the device's hardware characteristics, achieving precise six-DOF single-handed interaction without the need for additional physical buttons or a touchpad.

[0211] Example 11: Pressure-gated inertial navigation zero-velocity correction algorithm

[0212] Specifically, traditional inertial navigation writing pens rely on accelerometers to calculate displacement through double integration. Due to sensor noise and zero bias, the integration error diverges rapidly over time. A zero-velocity correction algorithm must be used periodically to zero the velocity to eliminate the error. However, traditional pens use capacitive or thin-film pressure detection units to determine whether the pen tip is stationary, which suffers from signal hysteresis and misjudgment, leading to inaccurate correction timing and resulting in trailing or broken trajectories.

[0213] This embodiment details the trajectory restoration technology, focusing on solving the trajectory drift problem caused by accumulated errors in the inertial navigation system when writing on ordinary media such as paper that are no longer on the screen. Utilizing the mechanical displacement characteristics of the floating sensor module, the following correction strategy is implemented:

[0214] Step 1: Generating mechanical gate control signals:

[0215] When the pen tip contacts the paper and is subjected to force, the floating module physically retracts, causing the pressure detection unit reading to jump instantaneously. Because the mechanical structure's rebound is extremely rapid and has a definite physical stroke, this pressure jump signal serves as a high-confidence gating signal for determining whether the pen tip is absolutely stationary (anchored to the paper) or absolutely suspended.

[0216] Step Two: Multi-Source Data Fusion and State Constraints

[0217] The microcontroller 70 runs an extended Kalman filter (EKF) algorithm, switching the state equations according to the pressure gating signal:

[0218] When pressure At this point, the system determines that the pen tip is anchored, and then introduces the micro-texture displacement output from the image acquisition and transmission unit. As an observation, the integrated displacement of the inertial measurement unit Position updates and drift compensation are performed. The high precision of optical flow data effectively suppresses long-term IMU drift. Under pressure... When the system determines that the pen tip is suspended in the air, it immediately performs zero-speed correction, forcibly returning the speed state variable in the filter to zero and cutting off error accumulation.

[0219] Through the aforementioned algorithm, the device can generate continuous three-dimensional trajectory data with closed beginnings and ends and no drift on ordinary paper. Even after rapid continuous writing or writing for a long time, the digital trajectory can still maintain a high degree of overlap with the physical handwriting on the paper, achieving true paper-screen synchronization and offline note storage.

[0220] Example 12: Intelligent Multimodal Media Identification Circuit and State Machine Logic

[0221] This embodiment details the hardware circuitry and software logic for media identification, aiming to enable seamless automatic switching between touch screens, ordinary paper or desktops, and suspended states.

[0222] 1. Media identification circuit architecture:

[0223] To capture weak screen electrical characteristic signals and detect capacitance properties, this device constructs the following signal conditioning link:

[0224] The signal acquisition end uses a miniature ball 11 as a sensing probe, and the sensing signal is led out through the gold-plated spring pin inside the ball seat 12. The spring pin is connected to the signal input node on the main control circuit board 80.

[0225] The signal input node consists of two parallel detection circuits:

[0226] The first path is a carrier detection circuit. The signal first passes through a high-pass filter with a cutoff frequency set to 50kHz to filter out human body power frequency interference and environmental electrostatic noise. The filtered high-frequency signal enters a high-gain operational amplifier with a gain setting greater than 100. The amplified signal is then connected to the timer input capture pin of the microcontroller 70 for measuring the signal frequency and duty cycle.

[0227] The second path is a self-capacitance detection circuit. The signal is connected to a dedicated touch detection chip or the built-in capacitance sensing module of the microcontroller 70. This module monitors the parasitic capacitance value of the signal input node to ground in real time using the charge-discharge time measurement method or the relaxation oscillator principle, denoted as . .

[0228] In addition, to resolve the electrical conflict between high-voltage transmission and weak signal reception when the sphere acts as a single probe, the main control circuit board 80 is equipped with a transceiver isolation analog switch controlled by the microcontroller 70. During the initial detection phase or in independent input mode, the switch connects the sphere to the signal input node for carrier sniffing, while simultaneously placing the high-voltage drive circuit in a high-impedance state. After confirming entry into the screen interaction mode, the microcontroller 70 uses a time-division multiplexing (TDD) mechanism to control the switch to briefly close the receiving circuit during screen scanning intervals to maintain signal synchronization. During the handwriting coordinate transmission period, the receiving circuit is disconnected and the high-voltage drive circuit is activated, thereby effectively protecting the front-end receiving amplifier from high-voltage signal saturation interference.

[0229] 2. State machine transition logic:

[0230] The microcontroller 70 runs a periodic state machine with a sampling frequency set to 100Hz. The specific state judgment logic is as follows:

[0231] State 1: Screen electrical characteristic signal detection:

[0232] This state has the highest decision priority. The microcontroller 70 continuously monitors the input frequency of the carrier detection circuit, denoted as... ,like The signal frequency remains stable within the scanning frequency range of mainstream touchscreens, such as 90kHz to 500kHz, and the signal amplitude exceeds the preset carrier threshold. If the system detects an error, it immediately determines that it is in screen interaction mode. In this mode, the system activates the Bluetooth human-machine interface device protocol, simulating a digital stylus, and sends pressure and button data to the screen. At this time, the image acquisition and transmission unit can be selectively activated to assist in positioning, or deactivated to reduce power consumption, depending on user configuration.

[0233] State 2: Pressure and Movement Detection

[0234] If no valid screen electrical characteristic signal is detected in the aforementioned state one, the microcontroller 70 will read the pressure value output by the pressure sensor. and the displacement vector output by the image acquisition and transmission unit and image surface quality factor;

[0235] If the pressure value Pressure contact threshold greater than preset For example, if the capacitance value is greater than 10 grams, the system determines that it is currently in independent input mode. In this determination logic, even if the self-capacitance detection circuit measures a large capacitance value... For example, when a user writes on their palm, the system remains in independent input mode due to the lack of screen electrical signatures. The system uses optical flow data to record the trajectory and stores it in local flash memory or transmits it wirelessly to an external application. This logic avoids misinterpretations caused by large capacitive objects like the palm, preventing data loss.

[0236] If the pressure value Less than the pressure contact threshold But displacement vector If the value is not zero, it indicates that there is floating movement, and the system determines that the current state is the air cursor mode (corresponding to the floating state in independent input mode). If the pressure value... Less than the pressure contact threshold And displacement vector If the value remains zero for more than a preset time, such as 5 seconds, the system determines that it is currently in a hibernation / standby state.

[0237] For scenarios involving cross-screen interaction on ordinary non-touch displays (where there is no carrier signal), this device distinguishes between continuous input actions and cursor click actions through spatiotemporal feature analysis. When the pen tip touches the screen or desktop, the pressure value P undergoes a step change, satisfying... The microcontroller 70 opens a very short evaluation time window, for example, 100 milliseconds. If the pressure signal rapidly drops back to normal within this time window... The following are macroscopic lateral or longitudinal displacement vectors obtained based on the integral of the sphere surface texture. If the vibration is less than the preset jitter threshold, which is mainly manifested as axial displacement caused by the axial retraction of the ball, the system determines that the current user intent is a short tap. At this time, the microcontroller 70 does not output a continuous input trajectory, but instead directly maps the contact and pressure signal into a single click command of the spatial cursor, such as a left mouse button click, thus perfectly meeting the user's seamless cross-screen interaction needs between continuous desktop operation and instantaneous screen selection.

[0238] Based on the above logic, this device can accurately distinguish between four typical scenarios: a mobile phone placed on a table, the palm of your hand, a regular computer monitor, and ordinary paper, thus achieving intelligent adaptation across all scenarios.

[0239] Example 13: Trajectory Accuracy Compensation Algorithm Based on Optical Geometry

[0240] This method is mainly for low-cost derivative models that do not have a floating imaging module, or for further calibrating the small residual errors of the floating module to ensure the consistency of cursor movement under different pressures.

[0241] 1. Optical geometry model and sensitivity drift problem:

[0242] Let the focal length of the lens of the image acquisition and transmission unit be... The axial distance from the imaging object to the optical center of the lens is defined as the surface texture of the sphere. According to the Gaussian imaging formula, the imaging magnification is... Defined as focal length Distance from object Subtract focal length The ratio of the differences.

[0243] When the device is in an unloaded state, the initial object distance is denoted as... The initial magnification is denoted as .

[0244] When the user applies pressure to write, the spherical assembly retracts axially, resulting in an increase in object distance, denoted as . This value is obtained from the pressure sensor reading or directly measured by the displacement sensor. Specifically, The spring compression in the aforementioned mechanical derivation They are equal in quantity. At this point, the actual object distance becomes... Plus The actual magnification becomes .

[0245] Obviously, an increase in the actual object distance leads to an increase in the actual magnification. Less than the initial magnification This means that for the same physical distance the sphere moves on its surface, the pixel displacement on the sensor target surface will be smaller. Without compensation, users will perceive a slower mouse movement when writing with pressure, i.e., a decrease in dots per inch (DPI).

[0246] 2. Real-time compensation algorithm flow:

[0247] The microcontroller 70 internally operates the following compensation loop:

[0248] Step 1: Calculate the compensation coefficient

[0249] Based on the aforementioned geometric relationship, the compensation coefficient Defined as initial magnification Compared with the current magnification The ratio of .

[0250] Substituting the imaging formula, we obtain the compensation coefficient. equal to the initial object distance Add displacement Subtract the focal length The value, divided by the initial object distance Subtract focal length The value of .

[0251] Due to focal length and initial object distance Given the structural constants and displacements For real-time measurements, the microcontroller 70 can quickly calculate the current compensation coefficient. Under stress, this coefficient It is usually greater than or equal to 1.

[0252] Step 2: Optical flow data correction:

[0253] The raw displacement output by the image acquisition and transmission unit includes lateral displacement. and longitudinal displacement To address the spherical perspective distortion introduced by the high curvature of the microsphere 11, the microcontroller 70 first performs spatial flattening correction on the original vector using a preset spherical back projection matrix; subsequently, the corrected displacement is multiplied by the dynamic compensation coefficient. Finally, the corrected output displacement is calculated. and Through this spherical flattening+ With dual correction steps of axis scaling, the system not only restores the true physical arc length of the sphere, but also eliminates nonlinear calculation errors caused by the slight retraction of the pen tip and the rotation of the high-curvature spherical surface, ensuring a high-precision linear operation experience under extremely small spherical tips.

[0254] Step 3: Suppression of axial pseudo-displacement:

[0255] Displacement amount when the user quickly taps the pen tip A step change will occur. Due to the principle of perspective, this axial movement will generate a radial optical flow field centered on the optical axis on the image sensor 312, similar to the zoom effect when zooming in.

[0256] The microcontroller 70 monitors the characteristics of the optical flow vector field in real time. If the motion vectors of all detected feature points point towards or away from the image center, and the displacement is... If the derivative with respect to time, i.e., the rate of change, exceeds a set threshold, the system identifies this as a pseudo-displacement generated by a click action. At this instant, typically within 10 to 20 milliseconds, the microcontroller 70 will output the displacement. and Force the cursor to zero or retain the value from the previous frame to eliminate cursor jitter when clicking, thus enabling precise selection.

[0257] Example 14: Mechanical Implementation of Adjustable Preload

[0258] This embodiment corresponds to claim 10. To accommodate different users' preferences for writing pressure, i.e., the feel of a hard pen versus a soft pen, this device includes a preload adjustment mechanism 41 at the rear of the pen barrel to adjust the feel. Figure 2 As shown.

[0259] The preload adjustment mechanism 41 includes a limiting adjustment ring screwed into the internal thread of the pen body 20. The rear end of the spring-loaded spring 40 abuts against the end face of the adjustment ring. When the user rotates the knob at the end of the pen body, the adjustment ring moves axially.

[0260] In hard-pen mode, the user rotates the adjustment ring forward 2mm. This adds an extra 2mm of pre-compression to the spring. Assuming a spring stiffness of 0.2N / mm, the preload increases by 0.4N (approximately 40g). This means the user must apply a force greater than 40g for the pen tip to begin moving. This hard-start feel is suitable for quick signatures or clicks, eliminating the looseness of the pen tip.

[0261] In soft-pen mode, the user rotates the adjustment ring to release the pre-pressure. At this point, the pen tip moves instantly upon contact, making it suitable for delicate sketching or calligraphy.

[0262] Example 15: Capacitor Signal Enhancement Scheme

[0263] This embodiment describes in detail how to solve the touch problem of the microsphere 11 on a capacitive screen.

[0264] Because the physical contact area between the miniature sphere 11 and the screen is much smaller than that of a finger, a capacitor signal enhancement unit 60 is integrated on the main control circuit board 80 to ensure that the touch signal is recognized by the screen. When this unit includes a boost circuit such as a charge pump or an inductor boost converter, the battery voltage is boosted and modulated into a high-frequency square wave signal with a peak-to-peak value between 15V and 35V (preferably 25V) and applied to the sphere. This high-voltage excitation signal can effectively penetrate the screen glass and protective film, compensating for the capacitance attenuation caused by the small contact area; at the same time, since the high-voltage circuit is configured with high internal resistance and microampere-level current limiting output, it not only meets human contact safety standards but also effectively controls the overall power consumption of the device.

[0265] Furthermore, such as Figure 7 As shown, the auxiliary radiating electrode 61 surrounds the microsphere in a ring shape, and its front end face is slightly recessed relative to the apex of the sphere, so that it does not contact the screen during writing. In the first structural implementation, the sphere base 12 is an insulator, and the auxiliary radiating electrode 61 is embedded in its front opening; in the second structural implementation that pursues extreme miniaturization (such as the shape of a ballpoint pen tip), the sphere base 12 is made entirely of a conductive metal material, and its front micro-concave cone itself constitutes the auxiliary radiating electrode 61. This extremely thin metal cone produces a very small physical contact area when tilted, which will not cause large-area accidental touches on the screen. Regardless of the structure used, the radiating electrode is connected to a high-voltage driving circuit, which significantly expands the equivalent electric field coverage of the pen tip through the edge electric field effect, ensuring that the signal remains stable during rapid writing or pen tilting.

[0266] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

[0267] The specific values ​​of voltage parameters, pressure thresholds, frequency ranges, and various coefficients involved in this invention are merely example parameters in preferred embodiments. Those skilled in the art can adjust them according to different application scenarios, device sizes, and system design requirements. These adjustments do not constitute a limitation on the scope of protection of this invention.

Claims

1. An intelligent dual-mode all-media digital input device, characterized in that, It includes a pen body, a conductive textured ball assembly, an image acquisition and transmission unit, a capacitive signal enhancement unit, a pressure detection unit, and a microcontroller; The conductive textured ball assembly is located at the front end of the pen body and includes microspheres. The surface of the microspheres is covered with an optical diffuse reflection texture for optical flow tracing and has conductive properties. The image acquisition and transmission unit is located inside the pen body, with its optical axis pointing towards the surface of the microsphere, and is configured to acquire texture images of the surface of the microsphere; The capacitor signal enhancement unit is electrically connected to the microsphere and is configured to load an enhanced capacitive coupling signal onto the microsphere; The pressure detection unit is configured to detect the axial pressure on the conductive textured ball assembly; The microcontroller is configured to control the device to switch between screen interaction mode and independent input mode. In the screen interaction mode, the microcontroller activates the capacitive signal enhancement unit and outputs active capacitive touch signal to the external touch screen through the microsphere. In independent input mode, the microcontroller activates the image acquisition and transmission unit to acquire two-dimensional optical flow displacement data on the surface of the microsphere, and combines it with the axial pressure data output by the pressure detection unit to generate a multi-dimensional input command that includes physical displacement and pressing state.

2. The intelligent dual-mode all-media digital input device according to claim 1, characterized in that, The conductive textured ball assembly and the image acquisition and transmission unit are assembled into a floating sensing module. The floating sensing module is configured to be axially displaced relative to the pen body and held in its initial position by an elastic reset member. The imaging input end of the image acquisition and transmission unit moves synchronously axially with the microsphere, so that the relative imaging object distance between the imaging input end and the surface of the microsphere remains constant during the axial displacement of the floating sensing module. The pressure detection unit is configured to determine the axial pressure on the conductive textured ball assembly by detecting the axial displacement of the floating sensing module.

3. The intelligent dual-mode all-media digital input device according to claim 1, characterized in that, The device also includes a media identification unit and a human-computer interaction interface; The medium identification unit is based on a microsphere and a touch circuit. The microcontroller determines the medium type by detecting the carrier signal of the contact surface conducted on the microsphere. When a threshold screen carrier signal is detected, it switches to the screen interaction mode; otherwise, it switches to the independent input mode. or, The microcontroller switches modes in response to user commands received from the human-computer interaction interface.

4. The intelligent dual-mode all-media digital input device according to claim 1, characterized in that, The capacitor signal enhancement unit includes a high-voltage drive circuit. The high-voltage drive circuit is configured to output an excitation signal with a peak-to-peak value of not less than 10V to compensate for insufficient capacitive coupling caused by the small contact area of ​​the microsphere.

5. The intelligent dual-mode all-media digital input device according to claim 2, characterized in that, The pressure detection unit is a displacement detection type pressure sensing structure, selected from at least one of optical displacement modulation structure, electromagnetic displacement detection structure or capacitive displacement detection structure, and is configured to determine the pressure signal by detecting the axial displacement of the floating sensing module relative to the pen body. If the optical displacement modulation structure is adopted, the floating sensing module is provided with an optical modulation feature, and a photodetector is provided at a relative position inside the pen body; the optical modulation feature is configured as a mark with optical property changes; the photodetector is configured to detect changes in light flux or pulse count caused by the axial displacement of the floating sensing module, and output the corresponding pressure signal.

6. The intelligent dual-mode all-media digital input device according to claim 1, characterized in that, The conductive textured ball assembly also includes a ball base, in which the microsphere is rotatably embedded. A portion of the microsphere is exposed through the front opening of the ball base, and the diameter of the microsphere is configured to be no greater than 16.0 mm. The outer sidewall of the ball seat is made of insulating material to block the electrical signal on the microsphere from leaking out laterally, allowing the electrical signal to radiate outward only from the front opening; The ball seat body is provided with elastic conductive contacts, which are configured to maintain dynamic contact with the micro sphere to transmit external electrical signals or capacitively coupled signals. The ball seat body is also provided with a friction support structure, which includes multiple micro support beads or support surfaces made of self-lubricating material, configured to form damped sliding contact or omnidirectional rolling contact with the microsphere; so that the static friction between the microsphere and the external contact medium is greater than the sum of the overall rolling friction and sliding friction resistance experienced by the microsphere in the ball seat body.

7. The intelligent dual-mode all-media digital input device according to claim 1, characterized in that, The device also includes an inertial measurement unit, which is used to detect the rotational angularity of the pen body around the central axis of the pen in real time; The microcontroller is configured to construct a rotation compensation matrix based on the detected rotation angle, and to perform coordinate system transformation on the two-dimensional coordinate data output by the image acquisition and transmission unit to correct the input trajectory direction deviation caused by the rotation of the grip posture, so that the coordinate system of the output trajectory always remains aligned with the coordinate system of the contact plane.

8. The intelligent dual-mode all-media digital input device according to claim 7, characterized in that, The microcontroller is configured to perform multi-source data fusion in the independent input mode; The microcontroller uses the pressure signal output by the pressure detection unit as a zero-speed correction gate signal. When the detected pressure signal is higher than a preset threshold, it determines that the state is in contact. It uses displacement data provided by the optical flow algorithm to constrain and correct the integral error of the inertial measurement unit. When the detected pressure signal is lower than a preset threshold, it determines that the state is in suspension. The microcontroller mainly calculates the spatial movement trajectory of the pen tip based on the data from the inertial measurement unit.

9. The intelligent dual-mode all-media digital input device according to claim 7, characterized in that, The microcontroller is configured with a spatial interactive control mode; In this mode, the device uses the pressure signal provided by the pressure detection unit as a continuously changing intensity control parameter, and uses the spatial attitude data provided by the inertial measurement unit as an orientation control parameter. The microcontroller is configured to continuously monitor the spatial posture of the pen body, and activate the spatial interaction control mode only when the pen posture is detected to conform to the preset non-writing control posture for a preset duration. In this mode, the device responds to the axial pressure signal applied to the microsphere. When the pressure signal exceeds a preset trigger threshold, the pressure amplitude is mapped to a multi-dimensional control command for the controlled object. At the same time, the tilt angle or three-dimensional orientation of the pen body is calculated in real time and mapped to the movement direction of the controlled object or the movement trajectory of the navigation cursor. This constructs a three-dimensional interactive mechanism based on adjusting the intensity of the press depth and defining the direction of the spatial posture. The tilt angle of the pen body is obtained in real time based on the inertial measurement unit.

10. The intelligent dual-mode all-media digital input device according to claim 2, characterized in that, The device is further provided with a preload adjustment mechanism, which is used to change the initial compression of the elastic reset member in order to adjust the starting pressure threshold for the floating sensing module to generate displacement.

11. A control method for an intelligent dual-mode all-media digital input device as described in any one of claims 1 to 10, characterized in that, Includes the following steps: Step S1: Detect the current mode switching trigger source, wherein the mode switching trigger source includes an active trigger command or an automatic media identification result; Step S2: If the current mode switching trigger source is detected to be an active trigger command, then switch to the command trigger mode of the active trigger command in response to the active trigger command, wherein the command trigger mode is a screen interaction mode or an independent input mode; Step S3: If the current mode switching trigger source is detected as an automatic media identification result, then the following sub-steps are performed based on the automatic media identification result: Sub-step S3.1: Continuously monitor the electrical and pressure signals of the contact surface using the conductive textured ball assembly; Sub-step S3.2: Determine whether a screen electrical characteristic signal of a preset frequency has been detected; Sub-step S3.3: If a screen electrical characteristic signal is detected, it is determined to be a screen interaction mode, and a capacitive touch signal is output; Sub-step S3.4: If no screen electrical feature signal is detected, and the detected pressure signal is higher than the preset threshold, then it is determined to be a contact input state in independent input mode, and the image acquisition and transmission unit is started to perform texture optical flow tracking and generate motion trajectory; Sub-step S3.5: If no screen electrical characteristic signal is detected and the pressure signal is lower than the preset threshold, it is determined to be a floating state of independent input mode, and cursor control data is generated or sleep mode is entered.

12. The control method according to claim 11, characterized in that, After entering the screen interaction mode in sub-step S3.3 or step S2, the image acquisition and transmission unit is turned off according to the preset configuration, and only the touch coordinates fed back by the external screen are used as positioning data. or, Keep the image acquisition and transmission unit turned on, use the optical flow algorithm to obtain the two-dimensional motion vector of the microsphere, and perform auxiliary verification or interpolation fusion on the touch coordinates fed back by the external screen to generate high-frequency positioning data to fill the screen touch sampling gap.

13. The control method according to claim 11, characterized in that, The method further includes a trajectory accuracy compensation step, which is executed by the microcontroller to correct imaging distortion and sensitivity drift caused by the axial movement of the microsphere. This step includes the following steps: Step 1: Real-time acquisition of the axial displacement of the conductive textured ball assembly or the corresponding pressure sensing value; Step 2: Based on the axial displacement and the imaging optical path geometry, calculate the current imaging magnification change coefficient in real time. Step 3: Using the aforementioned variation coefficient, perform reverse scaling compensation on the original two-dimensional pixel displacement output by the optical flow algorithm to eliminate the nonlinear attenuation of the number of dots per inch caused by the sphere's retreat. Step 4: Monitor the characteristics of the optical flow vector field. When a step change in the axial displacement is detected and the optical flow vector exhibits radial contraction or expansion characteristics centered on the optical axis, it is determined to be axial interference generated by the click action. The two-dimensional displacement output corresponding to the axial interference is suppressed or filtered.

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