Multi-functional capacitive sensing device

Abstract

The invention relates to a multi-functional capacitive sensing device, which includes: a first printed circuit board, a display, a sensor, a microcontroller unit (MCU), a sensor driver integrated circuit (IC), a second printed circuit board, and a display circuit. The display is used to display real-time information. The sensor is used to detect a user’s fingerprint image, writing trajectory, and / or electronic signature to generate sensing signals. The MCU is used to process data from the sensor and the display. The sensor driver IC is used to drive the sensor and process the sensing signals. The second printed circuit board is used for transmitting sensing signals and power distribution. The display circuit provides power and sensing signals to the display, transmits the data processed by the MCU to the display circuit, and the display circuit then shows the real-time recognition results on the display.

Description

Technical Field

[0001] This invention relates to a composite functional capacitive sensing device, and more specifically to a composite functional capacitive sensing device in which the transparency of a transparent glass fingerprint sensor is integrated with the display, and can provide relevant information in a timely manner. Prior Technology

[0002] Modern electronic signature pads integrate high-precision touch and pressure-sensitive technology, accurately capturing the thickness and pressure of the user's strokes to realistically reproduce the handwriting effect. Many electronic signature pads further incorporate transparent glass display technology (such as OLED), allowing signatures to be displayed instantly on the screen and integrated with other devices (such as touchscreens) for a more intuitive user experience. In addition, electronic signature pads support multiple connectivity methods such as Bluetooth and Wi-Fi, and combine with cloud technology to achieve instant storage and sharing of signed documents. As an important tool for paperless office work, electronic signature pads play a significant role in improving office efficiency and data security. With continuous technological advancements and expanding application scenarios, their market potential is enormous, and they are expected to occupy an increasingly important position in the digital economy.

[0003] Meanwhile, fingerprint sensors in biometric technology are also developing rapidly, providing a secure and reliable solution for identity verification. Optical fingerprint sensors capture fingerprint images using the principle of light reflection or penetration, and are mainly used in the under-screen fingerprint unlocking function of smartphones. Capacitive fingerprint sensors capture fingerprints by measuring the current or voltage change between the skin and the sensor, and are widely used in smartphones, laptops, and identity verification devices. Ultrasonic fingerprint sensors capture fingerprint details using ultrasonic beams, offering higher accuracy and security, and are particularly suitable for fingerprint recognition in wet hands or complex scenarios. In contrast, thermal fingerprint sensors scan by detecting the temperature difference on the fingerprint surface; although the technology is simple, its accuracy is lower than other methods. Fingerprint sensors are developing towards higher precision, integration, and multi-functionality, and are being widely used in many fields. With continuous technological breakthroughs and increasing market demand, the future development potential of fingerprint sensors is enormous, especially in the deeper and more diversified applications in smart devices, security, and fintech.

[0004] However, current electronic signature pads cannot capture fingerprint images, and fingerprint sensors have not yet been integrated into these products. Furthermore, mobile phone fingerprint functionality is limited to single-user use, and the fingerprint sensing area is too small, making it ineligible for FBI-IQS certification and difficult to integrate with electronic signature functions. These limitations reduce the comprehensiveness of functionality and ease of use in practical applications. Therefore, integrating electronic signature pads with fingerprint sensor technology has become a crucial requirement, not only enhancing the versatility and practicality of devices but also better meeting market expectations for efficient and secure digital solutions. In the future, the combined application of these technologies will continue to play a vital role in paperless office environments, data security, and smart devices.

[0005] In summary, in order to overcome the above-mentioned shortcomings, the inventors of this case have devoted a great deal of research and development energy and spirit to continuous breakthroughs and innovations in this field, hoping to solve the deficiencies of conventional methods with novel technical means, so as to bring better products to society and promote industrial development. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides an electronic signature device with capacitive sensing capabilities. The device features a highly transparent glass fingerprint sensor that integrates seamlessly with the display, providing real-time information and combining with electronic signature functionality for a unified design. This design significantly reduces the space requirements of the user organization, avoiding the need to place multiple single-function devices on a desktop, making it ideal for applications such as POS machines, banking services, and identity verification. Furthermore, the glass fingerprint sensor can operate independently. In fingerprint sampling mode, the OLED display prompts the user for the correct pressing method and instantly displays the fingerprint image; in electronic signature mode, the OLED displays the signature text instantly. When fingerprint or signature modes are not in use, the OLED display can also be used to play introductory videos, further enhancing the device's functionality and application flexibility.

[0007] To achieve the aforementioned objectives, this invention discloses a composite functional capacitive sensing device comprising: a first printed circuit board, a display, a sensor, a microcontroller unit (MCU), a sensor driver IC, a second printed circuit board, and a display circuit. First, the display, positioned above the first printed circuit board, has high transparency and is used to display real-time information. Second, the sensor, positioned above the display, is used to sense a user's fingerprint image, writing trace, and / or electronic signature to generate a plurality of sensing signals. Third, the MCU is positioned below the first printed circuit board and electrically connected to the display and the sensor via the first printed circuit board, used to process data from the sensor and the display, and control the operation of fingerprint recognition, writing trace recognition, and / or electronic signature. Finally, the sensor driver IC, positioned below the first printed circuit board, is electrically connected to the sensor via a data line, used to drive the sensor and process the sensing signals, and transmit the processed sensing signals to the MCU through a data channel. Furthermore, the second printed circuit board is disposed below the microcontroller unit and the sensor driver integrated circuit, and is electrically connected to the sensor and the microcontroller unit through the data lines or solder points to transmit the sensing signals and distribute power. In addition, the display circuit is disposed below the second printed circuit board and is electrically connected to the display. The display circuit provides power and the sensing signals to the display, and sends the data processed by the microcontroller unit to the display circuit. The display circuit then displays the real-time fingerprint recognition results, writing traces, electronic signature samples, and other relevant information on the display.

[0008] In the composite functional capacitive sensing device of the present invention, the sensor includes: a substrate; a signal processing circuit layer disposed above the substrate for extracting a fingerprint feature and / or a handwriting feature; an interconnect layer electrically coupled to the signal processing circuit layer and used to transmit a capacitance signal; an electrode array layer electrically coupled to the interconnect layer and including a plurality of electrodes arranged in a plurality of matrix arrays for sensing a capacitance value change function of a contact object relative to the electrode array layer, thereby obtaining a fingerprint, writing trajectory (handwriting or text), and / or an electronic signature; and a dielectric layer electrically coupled to the electrode array layer and used to isolate the electrodes, prevent short circuits, and enhance the capacitance effect.

[0009] The composite functional capacitive sensing device of the present invention further includes a flexible printed circuit board connector (FPC connector) disposed below the second printed circuit board for electrically connecting the composite functional capacitive sensing device to an external device for data transmission or exchange of control commands.

[0010] In the composite functional capacitive sensing device of the present invention, the sensor driving integrated circuit amplifies and processes the sensing signals sensed by the sensor, and transmits the processed signals to the microcontroller unit for analysis.

[0011] In the composite functional capacitive sensing device of the present invention, the sensor includes a multi-functional sensing unit that can simultaneously perform fingerprint recognition, writing trajectory recognition and / or electronic signature sensing, and transmit the corresponding sensing signals to the microcontroller unit for analysis and processing.

[0012] In the composite functional capacitive sensing device of the present invention, the multifunctional sensing unit further includes a fingerprint recognition element for sensing the fingerprint image of the user and generating a corresponding fingerprint recognition signal, and the microcontroller unit is used to process the fingerprint recognition signal to perform fingerprint recognition operation.

[0013] In the composite functional capacitive sensing device of the present invention, the multifunctional sensing unit further includes a pressure sensing element for sensing the pressure applied by the user to the sensor and generating a corresponding pressure sensing signal, and the microcontroller unit for processing the pressure sensing signal to adjust the pressure sensitivity and pen pressure sensing.

[0014] In the composite functional capacitive sensing device of the present invention, a hard coating is further included, which covers the sensor. The hard coating is made of at least one transparent and wear-resistant material selected from polycarbonate, silicon oxide, silicon oxynitride, ultraviolet-cured polymer, fluorinated polymer, diamond-like carbon (DLC), polyurethane, and combinations thereof.

[0015] In the composite functional capacitive sensing device of the present invention, a layered electrostatic discharge protection layer is further included, which is disposed between the hard coating and the sensor and connected to the signal pin or power pin of the sensor to prevent damage from electrostatic discharge. Simple Explanation of the Diagram

[0016] Figure 1 is a schematic diagram of the composite functional capacitive sensing device of Embodiment 1 of the present invention. Figure 2 is a schematic cross-sectional view of the sensor of the composite functional capacitive sensing device of Embodiment 1 of the present invention. Figure 3 is a schematic block diagram of the sensor and sensor driving integrated circuit of the composite functional capacitive sensing device of Embodiment 1 of the present invention. Figure 4 shows a structural diagram of the sensing matrix of the sensor in Embodiment 1 of the present invention. Figure 5 is a schematic diagram of the composite functional capacitive sensing device of Embodiment 2 of the present invention. Figure 6 is a schematic diagram of the composite functional capacitive sensing device of Embodiment 3 of the present invention. Figure 7 is a schematic diagram of the composite functional capacitive sensing device of Embodiment 4 of the present invention. Figure 8 is a schematic diagram of the composite functional capacitive sensing device of Embodiment 5 of the present invention. Figure 9 is a schematic diagram of the composite functional capacitive sensing device of Embodiment 6 of the present invention. Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the invention are now described in detail with reference to the accompanying drawings. The detailed description and technical content of the present invention are illustrated below in conjunction with the accompanying drawings; however, the accompanying drawings are provided for reference and illustration only and are not intended to limit the scope of the invention.

[0018] In addition, it should be understood that when a component is indicated as "connected" or "electrically coupled" to another component, it can be directly connected or coupled to the other component, or there can be an intermediate component.

[0019] Please refer to Figure 1, which is a cross-sectional view of the composite functional capacitive sensing device of Embodiment 1 of the present invention.

[0020] As shown in Figures 1 and 2, the present invention describes a composite functional capacitive sensing device 1 comprising: a first printed circuit board 10, a display 20, a sensor 30, a microcontroller unit 11, a sensor driving integrated circuit 12, a second printed circuit board 40, and a display circuit 41.

[0021] First, the display 20 is positioned above the first printed circuit board 10, has high transparency, and is used to display real-time information. The display 20 can be an OLED display, an LCD display, or a touch display, used to display various real-time information and receive user commands.

[0022] Secondly, the sensor 30 is disposed above the display 20 and is used to sense a user's fingerprint image, writing trajectory, and / or electronic signature to generate multiple sensing signals. The sensor 30 employs multi-touch technology, enabling it to simultaneously sense multiple contact points and accurately identify them based on the multi-touch signals. The sensor 30 includes a multi-functional sensing unit capable of simultaneously sensing fingerprint recognition, writing trajectory recognition, and / or electronic signatures, and transmitting the corresponding sensing signals to the microcontroller unit for analysis and processing. In one embodiment, the multi-functional sensing unit further includes a fingerprint recognition element for sensing the user's fingerprint image and generating a corresponding fingerprint recognition signal, and the microcontroller unit 11 processes the fingerprint recognition signal to perform fingerprint recognition operations. In another embodiment, the multi-functional sensing unit further includes a pressure sensing element for sensing the pressure applied by the user to the sensor and generating a corresponding pressure sensing signal, and the microcontroller unit processes the pressure sensing signal to adjust pressure sensitivity and pen pressure sensing.

[0023] Furthermore, the microcontroller unit 11 is disposed below the first printed circuit board 10, and is electrically connected to the display 20 and the sensor 30 through the first printed circuit board 10. It processes data from the sensor 30 and the display 20, and controls fingerprint recognition, writing trajectory recognition, and / or electronic signature operations. The data processing performed by the microcontroller unit 11 includes fingerprint recognition algorithms, writing trajectory recognition algorithms, and / or electronic signature recognition algorithms.

[0024] Next, the sensor driver integrated circuit 12 is disposed below the first printed circuit board 10 and electrically connected to the sensor 30 via a data line. It drives the sensor 30 and processes the sensing signals, then transmits the processed sensing signals to the microcontroller unit 11 through a data channel. The sensor driver integrated circuit 12 amplifies and processes the sensing signals sensed by the sensor 30 and transmits the processed signals to the microcontroller unit 11 for analysis.

[0025] Furthermore, the second printed circuit board 40 is disposed below the microcontroller unit 11 and the sensor drive integrated circuit 12, and is electrically connected to the sensor 30 and the microcontroller unit 11 through the data line or solder joint to transmit the sensing signals and distribute power.

[0026] In addition, the display circuit 41 is located below the second printed circuit board 40 and is electrically connected to the display 20. The display circuit 41 provides power and sensing signals to the display 20 and sends the data processed by the microcontroller unit 11 to the display circuit 41. The display circuit 41 then displays the real-time fingerprint recognition results, writing trajectory, electronic signature sample and other related information on the display 20.

[0027] Please refer to Figure 2, which is a schematic cross-sectional view of the sensor of the composite functional capacitive sensing device of Embodiment 1 of the present invention.

[0028] As shown in Figure 2, the sensor 30 includes: a substrate 31, a signal processing circuit layer 32, an interconnect layer 33, an electrode array layer 34, and a dielectric layer 35. The signal processing circuit layer 32 is disposed above the substrate 31 and is used to extract a fingerprint feature and / or handwriting feature. The interconnect layer 33 is electrically coupled to the signal processing circuit layer 32 and is used to transmit a capacitance signal. Furthermore, the electrode array layer 34 is electrically coupled to the interconnect layer 33 and includes a plurality of electrodes 341 arranged in a plurality of matrix arrays for sensing a capacitance change function of a contact object relative to the electrode array layer 34, thereby obtaining a fingerprint, writing trajectory (handwriting or text), and / or electronic signature. The contact object is at least one selected from the following: a finger, palm, toe, electronic pen, writing instrument, and combinations thereof. Moreover, the dielectric layer 35 is electrically coupled to the electrode array layer 34 and is used to isolate the electrodes, prevent short circuits, and enhance the capacitance effect.

[0029] Please refer to Figure 3, which is a schematic block diagram of the sensor and sensor driving integrated circuit of the composite functional capacitive sensing device of Embodiment 1 of the present invention.

[0030] As shown in Figure 3, an internal circuit 121 of the sensor driver integrated circuit 12 includes a clock generator 1221, a receiving sensing unit 1222, a transmitting sensing unit 1223, a signal buffer unit 1224, and a signal transmission element 1225. With the help of the clock signal Sck generated by the clock generator 1221, the receiving sensing unit 1222, the transmitting sensing unit 1223, the signal buffer unit 1224, and the signal transmission element 1225 perform regular sensing steps. During the sensing steps, in response to an activation command provided by the user, the transmitting sensing unit 1223 is configured to receive the clock signal Sck and generate an initial sensing signal Si and a control signal Sc, and transmits the initial sensing signal Si to the contact object through the signal buffer unit 1224 and the signal transmission element 1225. The transmission sensing unit 1223 is configured to send the initial sensing signal Si or the control signal Sc to the receiving sensing unit 1222 to synchronize the receiving of the sensing signals and the elements in the receiving sensing unit 1222, such as switches.

[0031] Furthermore, the signal buffer unit 1224 is configured to buffer the initial sensing signal Si and generate a buffered sensing signal Sb. The signal buffer unit 1224 can also convert the voltage or current level of the initial sensing signal Si to another signal level to provide the driving capability required for the sensing step. The signal buffer unit 1224 includes at least one of a current amplification circuit and a level shifter, configured to generate the buffered sensing signal Sb in response to the initial sensing signal Si.

[0032] The signal transmission element 1225 is configured to generate a transmission sensing signal St in response to the buffer sensing signal Sb and transmit it to the contact. The signal transmission element 1225 can transmit the buffer sensing signal Sb through the contact or in a non-contact manner. In touch mode, the signal transmission element 1225 includes a conductive layer and / or a frame, and the buffer sensing signal Sb is transmitted through the conductive layer and / or the frame as the transmission sensing signal St. During a touch event, the contact approaches or contacts the electrode array layer 34 and receives the transmission sensing signal St. Therefore, a capacitance Cfinger is generated between the contact and the electrodes 341. The electrodes 341 can generate a reception sensing signal Sr, which is generated by the transmission sensing signal St transmitted to the contact and the capacitance Cfinger in response to the touch event.

[0033] The receiving sensing control unit 1222 is configured to receive the sensing signal Sr and generate a digital sensing signal Sd, which represents the sensing results provided by the electrodes 341 in response to a touch event. The digital sensing signal Sd can be transmitted to the microcontroller unit 11, where the individual digital sensing signals Sd detected by different electrodes 341 at different locations of the contact object are processed to form a processing signal Sp representing the contact object.

[0034] In one embodiment, when the contact object is a finger, the signal processing circuit layer 32 reads a fingerprint image of a fingerprint pattern and transmits the information to the sensor driving integrated circuit 12. The sensor driving integrated circuit 12 converts a first capacitance value C1(x,y) collected by the electrode array layer 34 into a corresponding primitive value I(x,y) through a grayscale mapping function f. The grayscale mapping function f adopts a logarithmic function form and satisfies the following relationship function (1): I(x,y)=f(C1(x,y)) ----------(1); Where C1(x,y) represents the first capacitance value measured by the electrode array layer at position (x,y); I(x,y) refers to the gray value of the primitive at position (x, y), representing the brightness of the image at (x, y).

[0035] Furthermore, the fingerprint feature extraction includes extracting the ridge bifurcation points and termination points in the fingerprint image. The fingerprint image is generated as a grayscale image based on the change of a first capacitance value. The area with a larger first capacitance value corresponds to the ridge of the fingerprint, and the area with a smaller first capacitance value corresponds to the valley of the fingerprint.

[0036] Each electrode 341 in the electrode array layer 34 includes a microcapacitor used to detect the ridges (contact portions) and valleys (non-contact portions) of a fingerprint. When a finger touches the electrode array layer 34, the conductivity of the fingerprint ridges changes the charging level of the microcapacitor, while the fingerprint valleys, lacking contact, generate different capacitance values. These capacitance values ​​are converted into electronic signals to generate a complete fingerprint image.

[0037] In another embodiment, the signal processing circuit layer 32 reads a stroke image from the pen tip of the writing instrument and transmits the information to the sensor driving integrated circuit 12. The sensor driving integrated circuit 12 reconstructs the stroke trajectory based on a second capacitance value C2(x,y), a writing speed v(x,y,t), and a writing pressure p(x,y,t) collected by the electrode array layer 34, using a function g that combines speed, pressure, and capacitance changes. The function g uses a Kalman filter model and satisfies the following relationship function (2): P(x,y,t)=g(C2(x,y,t),v(x,y,t),p(x,y,t)) ----------(2)

[0038] Where C2(x,y,t) represents the second capacitance value measured at time t and position (x, y) of the electrode array layer; v(x, y, t) represents the writing speed of the pen tip at time t and position (x, y); and p(x, y, t) represents the writing pressure applied by the pen tip at time t and position (x, y). Feature extraction of this handwriting trajectory includes analyzing the pressure, speed, direction, or turning points of the writing strokes to generate a signature verification handwriting trajectory; the reconstructed handwriting trajectory generates a path map based on changes in a second capacitance value, and the thickness, pressure, and / or speed of the writing strokes are analogized to the changes in this second capacitance value.

[0039] Please refer to Figure 4, which shows the structure diagram of the sensing matrix of the sensor in Embodiment 1 of the present invention.

[0040] As shown in Figure 4, NSEL1, NSEL2, NSEL3, NSEL4, FSEL1, FSEL2, FSEL3, and FSEL4 represent linear selection signals, controlling which linear path (1~32) is selected. Black and red dots indicate the control switches corresponding to the control lines. The red box indicates a permanent physical connection on the panel. RX1 to RX8 represent the receiving channel for the sensing signal; the sensor driver integrated circuit 12 is connected to this receiving channel to record signal changes. By changing the values ​​of control signals NSEL1, NSEL2, NSEL3, NSEL4, FSEL1, FSEL2, FSEL3, and FSEL4, both general fingerprint reading mode and stylus mode are achieved.

[0041] Figure 4 illustrates the image reading operation logic in pen mode, specifically the data processing method when the panel enters a fast mode to handle image data input by the pen. This fast mode is designed to improve image reading speed, especially during rapid writing or signing. When the panel enters fast mode, the image reading from the receiving channel undergoes "partial selection" to accelerate data processing. Specifically, partial selection involves reading image data only every 4 or 5 columns; that is, not every column of image data is read, but some columns are skipped to reduce the total amount of data.

[0042] Secondly, while a complete image would normally contain data from all columns, in this fast mode, the controller only processes a portion of the data—1 / 4 or 1 / 5 of the image—significantly reducing the amount of data read. When the data volume is reduced by 1 / 4 or 1 / 5, the total reading time for each image decreases accordingly, assuming the controller's reading speed remains constant. Therefore, the controller can process the entire image faster, thus improving the overall system's responsiveness. In pen mode, to accelerate image reading, the composite-function capacitive sensing chip 1 selects only a portion of the columns (every 4 or 5 columns) instead of reading the entire image. This reduces the amount of data processed, shortening image reading and processing time, resulting in a faster response, making it particularly suitable for scenarios requiring high-speed input, such as signing or rapid writing.

[0043] Please refer to Figure 5, which is a schematic diagram of the composite functional capacitive sensing device of Embodiment 2 of the present invention.

[0044] As shown in Figure 5, Embodiment 2 of the present invention is largely the same as Embodiment 1, except that the composite functional capacitive sensing device 1 of Embodiment 2 further includes a flexible printed circuit board connector (FPC connector) 42, which is disposed below the second printed circuit board 40, for electrically connecting the composite functional capacitive sensing device 1 to an external device for data transmission or exchange of control commands.

[0045] Please refer to Figure 6, which is a schematic diagram of the composite functional capacitive sensing device of Embodiment 3 of the present invention.

[0046] As shown in Figure 6, Embodiment 3 of the present invention is largely the same as Embodiment 1, except that the composite functional capacitive sensing device 1 of Embodiment 3 further includes a hard coating 50 covering the sensor 30. The hard coating 50 is made of at least one transparent and wear-resistant material selected from polycarbonate, silicon oxide, silicon oxynitride, ultraviolet-cured polymer, fluorinated polymer, diamond-like carbon (DLC), polyurethane, and combinations thereof.

[0047] Please refer to Figure 7, which is a schematic diagram of the composite functional capacitive sensing device of Embodiment 4 of the present invention.

[0048] As shown in Figure 7, Embodiment 4 of the present invention is largely the same as Embodiment 1, except that the composite functional capacitive sensing device 1 of Embodiment 3 further includes a layered electrostatic discharge protection layer (ESD Protection Layer) 60, disposed between the hard coating layer and the sensor, and connected to the signal pin or power pin of the sensor to prevent damage from electrostatic discharge. The ESD Protection Layer 60 is used to prevent electrostatic discharge (ESD) from damaging electronic devices or components. ESD is a phenomenon that rapidly releases electrostatic energy, which can have a destructive effect on sensitive electronic components, leading to component failure or performance degradation. Therefore, the ESD Protection Layer 60 is widely used in various electronic products and systems. The ESD Protection Layer 60 is composed of at least one material selected from conductive polymers, metal oxides, carbon-based materials, coating materials, and combinations thereof; wherein the conductive polymer includes polyaniline (PANI) or polyacetylene; the metal oxide includes indium tin oxide (ITO); the carbon-based material includes graphene or carbon nanotubes; and the coating material includes antistatic coatings or polyester films.

[0049] Please refer to Figure 8, which is a schematic diagram of the composite functional capacitive sensing device of Embodiment 5 of the present invention.

[0050] As shown in Figure 8, Embodiment 5 of the present invention is largely the same as Embodiment 1, except that the composite functional capacitive sensing device 1 of Embodiment 3 further includes at least one USB connector 43, disposed below the first printed circuit board or the second printed circuit board, for transmitting data and power hardware interface. It is widely used for connections between electronic devices. The USB connector 43 enables bidirectional data transmission between devices, such as data exchange between a computer and a tablet.

[0051] Please refer to Figure 9, which is a schematic diagram of the composite functional capacitive sensing device of Embodiment 6 of the present invention.

[0052] As shown in Figure 9, Embodiment 6 of the present invention is largely the same as Embodiment 1, except that the composite functional capacitive sensing device 1 of Embodiment 6 further includes an optically clear adhesive 70 and an outer frame (Bezel) 71. The optically clear adhesive 70 is a transparent adhesive material used in optical applications. Its main function is to bond different layers (such as glass, display screen, fingerprint sensor, etc.) with high transparency while maintaining optical performance. The high transparency of the optically clear adhesive reduces light reflection and scattering, enhances light penetration, and ensures that the fingerprint sensor can accurately capture fingerprint images. Secondly, by using the optically clear adhesive 70, interference caused by interface reflection or bubbles can be effectively reduced, thereby improving recognition accuracy; and the optically clear adhesive 70 not only stably bonds the fingerprint sensor to other layers but also provides a certain degree of shock resistance, dustproofing, and waterproofing protection. The high-quality optically clear adhesive 70 has anti-yellowing capabilities during long-term use, maintaining the optical and aesthetic performance of the fingerprint device.

[0053] As shown in Figure 9, the outer frame 71 is the bezel surrounding the hard-coated display screen 50. This outer frame 71 serves as a protective structure for the display 20 or the sensor 30, preventing damage during use or accidental impacts. The outer frame 71 helps secure the components in the composite-functional capacitive sensing device 1, ensuring stability and durability. In one embodiment, the outer frame 71 also integrates additional functions such as buttons, sensors, LED indicators, or speaker holes.

[0054] In summary, the composite-functional capacitive sensing device 1 of this invention provides instant and high-precision fingerprint recognition, which can be used for identity authentication and security protection. Writing trajectory and electronic signature sensing support the recording and recognition of handwriting, suitable for applications such as electronic signatures and data input, enhancing the interactive experience. Pressure sensing can detect applied pressure, further improving the sensitivity and accuracy of handwriting or touch. Secondly, the combination of the microcontroller unit 11 and the sensor driving integrated circuit 12 enables real-time processing of sensing signals (such as fingerprint feature extraction, handwriting recognition, etc.) and direct display of the results on the display, providing a seamless interactive experience. Furthermore, the display has high transparency, enabling clear display of real-time information, such as fingerprint recognition results or handwriting. Moreover, the wear-resistant and transparent hard coating 50 enhances the durability of the device, effectively protecting the sensor from scratches and damage. Finally, the electrostatic protective layer 60 provides electrostatic discharge protection, effectively preventing damage to the sensor from static electricity, enhancing system stability and lifespan. Furthermore, the design of the first printed circuit board 10, the second printed circuit board 40, and the flexible printed circuit board connector 42 enables efficient integration of functional modules and supports data exchange and control command interaction with external devices.

[0055] 1: Composite functional capacitive sensing device 10: First Printed Circuit Board 11: Microcontroller Unit 12: Sensor driver integrated circuit 121: Internal Circuit 1221: Clock Generator 1222: Receiver / Sensor Unit 1223: Transmission Sensing Unit 1224: Signal buffer unit 1225: Signal transmission element 20: Monitor 30: Sensor 31:Substrate 32: Signal Processing Circuit Layer 33: Interconnect layer 34: Electrode array layer 341: Electrode 35: Dielectric layer 40: Second Printed Circuit Board 41: Display circuit 42: Flexible Printed Circuit Board Connector 43: USB connector 50: Hard coating 60: Electrostatic discharge protective layer 70: Optical transparent adhesive 71: External Framework

Claims

1. A composite functional capacitive sensing device, comprising: The first printed circuit board; A display, positioned above the first printed circuit board, has high transparency and is used to display real-time information; A sensor, disposed above the display, is used to sense a user's fingerprint image, writing trajectory, and / or electronic signature to generate a plurality of sensing signals; a microcontroller unit (MCU), disposed below the first printed circuit board, is electrically connected to the display and the sensor through the first printed circuit board, and is used to process data from the sensor and the display, and control the operation of fingerprint recognition, writing trajectory recognition and / or electronic signature; a sensor driver integrated circuit (SFC), disposed below the first printed circuit board, is electrically connected to the sensor through a data line, and is used to drive the sensor and process the sensing signals, and transmit the processed sensing signals to the microcontroller unit through a data channel; A second printed circuit board is disposed below the microcontroller unit and the sensor driver integrated circuit, and is electrically connected to the sensor and the microcontroller unit through the data line or solder joint to transmit the sensing signals and distribute power; and a display circuit is disposed below the second printed circuit board and is electrically connected to the display. The display circuit provides power and the sensing signals to the display, and sends the data processed by the microcontroller unit to the display circuit. The display circuit then displays the real-time fingerprint recognition result, writing trajectory, electronic signature sample and other related information on the display.

2. The composite functional capacitive sensing device as claimed in claim 1, wherein the sensor comprises: a substrate; a signal processing circuit layer disposed above the substrate for extracting a fingerprint feature and / or a handwriting feature; an interconnect layer electrically coupled to the signal processing circuit layer for transmitting a capacitance signal; an electrode array layer electrically coupled to the interconnect layer and including a plurality of electrodes arranged in a plurality of matrix arrays for sensing a capacitance change function of a contact object relative to the electrode array layer, thereby obtaining a fingerprint, writing trace (handwriting or text), and / or an electronic signature; and a dielectric layer electrically coupled to the electrode array layer for isolating the electrodes, preventing short circuits, and enhancing the capacitance effect.

3. The composite functional capacitive sensing device as described in claim 1 further includes a flexible printed circuit board connector (FPC connector) disposed below the second printed circuit board for electrically connecting the composite functional capacitive sensing device to an external device for data transmission or exchange of control commands.

4. The composite functional capacitive sensing device as described in claim 1, wherein the sensor driving integrated circuit amplifies and processes the sensing signals sensed by the sensor, and transmits the processed signals to the microcontroller unit for analysis.

5. The composite-function capacitive sensing device as described in claim 1, wherein the sensor includes a multi-functional sensing unit capable of simultaneously performing fingerprint recognition, writing trajectory recognition, and / or electronic signature sensing, and transmitting the corresponding sensing signals to the microcontroller unit for analysis and processing.

6. The composite functional capacitive sensing device as described in claim 5, wherein the multifunctional sensing unit further includes a fingerprint recognition element for sensing the user's fingerprint image and generating a corresponding fingerprint recognition signal, and the microcontroller unit for processing the fingerprint recognition signal to perform fingerprint recognition operation.

7. The composite-function capacitive sensing device as described in claim 5, wherein the multi-function sensing unit further includes a pressure sensing element for sensing the pressure applied by the user to the sensor and generating a corresponding pressure sensing signal, and the microcontroller unit for processing the pressure sensing signal to adjust the pressure sensitivity and pen pressure sensing.

8. The composite functional capacitive sensing device as claimed in claim 1 further includes a hard coating covering the sensor, the hard coating being a transparent and abrasion-resistant material selected from polycarbonate, silicon oxide, silicon oxynitride, UV-curable polymer, fluorinated polymer, diamond-like carbon (DLC), polyurethane, and combinations thereof.

9. The composite functional capacitive sensing device as described in claim 8 further includes a layered electrostatic discharge protection layer disposed between the hard coating and the sensor, and connected to the signal pin or power pin of the sensor to prevent damage from electrostatic discharge.

10. The composite-function capacitive sensing device as described in claim 1 further includes at least one USB connector disposed below the first printed circuit board or the second printed circuit board, serving as a hardware interface for transmitting data and power, and for connection between electronic devices.

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