Capacitive stylus pressure sensing mechanism

Abstract

The utility model discloses a kind of capacitive pen pressure sensing mechanisms, including pen body, pen point and the gap protection cavity being arranged therebetween, inside is equipped with elastic pressure sensing mechanism, for axial displacement occurs under preset pressure and pen point pressure is transmitted to pressure sensor. Fixed cylinder is installed in pen body and is fixed with PCBA board fixed conduction, pressure sensor is arranged on PCBA board, force transmission sleeve is set in fixed cylinder, one end is contacted with pressure sensor, the other end contains elastic pressure sensing mechanism. Pre-pressure spring is arranged between fixed cylinder and elastic pressure sensing mechanism, for giving pressure sensor initial pressure value. The structure realizes stable transmission under normal pressure by elastic needle, retracts to protect sensor when overload, simultaneously adopt multi-stage conductive medium to conduct pen point signal, ensure signal transmission stable and reliable, realize high sensitivity pressure sensing detection and overload protection, with Compact structure, stable performance and long service life advantage.

Description

Technical Field

[0001] This utility model relates to a capacitive pen, specifically to a capacitive pen pressure-sensitive mechanism. Background Technology

[0002] Capacitive pens, as an important accessory for touch devices, are widely used in tablets, smartphones, and drawing equipment. Current capacitive pens typically achieve input or drawing functions through contact between the pen tip and the touchscreen. To enhance the user experience, some capacitive pens have added pressure sensitivity, which detects the amount of pressure applied to the pen tip to adjust the thickness and darkness of the strokes, making the writing and drawing effects more closely resemble realistic handwriting.

[0003] Among the existing capacitive pen pressure-sensitive implementations, common technical approaches mainly fall into two categories: one is based on capacitance change detection, which uses a conductive element at the pen tip combined with a capacitive sensing circuit to sense pressure; the other is based on a pressure sensor detection, which installs a pressure sensor inside the pen tip or in the middle of the pen body, and transmits the force on the pen tip to the sensor through a mechanical force transmission structure. However, these methods still have certain shortcomings in practical applications.

[0004] For example, some designs mount the pressure sensor directly at the pen tip. While this allows for relatively sensitive pressure detection, the limited space at the tip makes the sensor susceptible to damage from external impacts, and assembly is also more difficult. Other designs place the sensor inside the pen body, transmitting pressure via a force transmission rod or spring structure. However, this often results in uneven force transmission, slow response, or unstable signals due to assembly tolerances. Furthermore, improper control of the gap between the pen tip and the sensor can easily lead to misalignment or missed strokes, causing the pen to be unable to accurately detect pressure during light writing, thus affecting writing smoothness and accuracy.

[0005] Meanwhile, existing capacitive pens generally suffer from the following problems in their pressure-sensitive structure design: First, the conductive path between the pen tip and the sensor is complex, making it prone to poor contact or signal attenuation; second, the lack of an effective pre-pressure device prevents the formation of a stable initial force reference at the sensor end, leading to drift or inconsistency in the pressure-sensitive signal; third, while some solutions using metal force transmission components ensure conductivity, they pose risks in terms of insulation and signal isolation, affecting the overall circuit stability. These problems all limit the performance improvement of capacitive pen pressure-sensitive functions to some extent. Utility Model Content

[0006] To address the aforementioned issues, this invention provides a capacitive pen pressure-sensitive mechanism that achieves a compact, stable, responsive, and electrically conductive capacitive pen pressure lever mechanism within a limited pen body space.

[0007] This utility model is achieved through the following technical solution: a capacitive pen pressure-sensitive mechanism, comprising: The pen body and the pen tip, wherein the pen tip is mounted on the head of the pen body and a gap protective cavity is formed between the pen tip and the pen body; An elastic pressure-sensitive mechanism is disposed inside between the pen tip and the pen body, and is used to undergo axial displacement under a preset pressure, thereby transmitting the pressure on the pen tip to the pressure sensor. A fixed cylinder is fixedly connected to a PCBA board installed inside the pen body, and the pressure sensor is located on the PCBA board inside the fixed cylinder; A force-transmitting sleeve is installed inside the fixed cylinder, with one end of it contacting the force-receiving end of the pressure sensor, and the elastic pressure-sensing mechanism is installed inside the force-transmitting sleeve. A preload spring is disposed between the fixed cylinder and the elastic pressure-sensitive mechanism to provide the pressure sensor with an initial pressure value.

[0008] As a preferred technical solution, the elastic pressure-sensitive mechanism includes an elastic needle, a syringe, and a support spring. The support spring is installed inside the syringe. One end of the elastic needle is inserted into the pen tip and communicates with the pen tip, while the other end is inserted into the syringe and contacts the support spring for support.

[0009] As a preferred technical solution, the elastic needle is connected to the fixed cylinder through a pre-compression spring, and the pre-compression spring is connected to the elastic needle.

[0010] As a preferred technical solution, a conductive tube is also included. The conductive tube is installed between the fixed cylinder and the pen tip to transmit the signal from the pen tip to the PCBA board. One end of the fixed cylinder is conductively connected to the PCBA board, and the other end forms a stroke gap cavity with the pen tip.

[0011] As a preferred technical solution, the pen tip includes a conductive tip and a pen tip cap, the conductive tip is mounted on the pen tip cap, and one end of the elastic needle is inserted into the conductive tip and communicates with the conductive tip.

[0012] As a preferred technical solution, the force transmission sleeve is made of insulating non-metallic material.

[0013] As a preferred technical solution, the fixing cylinder and the PCBA board are connected by welding to form a conductive connection.

[0014] The beneficial effects of this invention are as follows: By setting an elastic pressure-sensitive mechanism between the pen tip and the pen body, and introducing an elastic needle structure within the mechanism, the pressure exerted on the pen tip during normal writing can be transmitted step by step to the pressure sensor through the elastic needle, support spring, and force transmission sleeve, ensuring the sensitivity and stability of pressure detection. When the user applies excessive pressure, the elastic needle will retract, thereby releasing excess axial stress and effectively preventing overload pressure from directly acting on the sensor, thus protecting the pressure sensor and significantly improving the overall reliability and service life of the device.

[0015] Furthermore, the pen tip signal conduction method of this invention adopts a multi-stage conductive transmission structure, that is, the conductive tip, elastic needle, pre-compression spring, and fixing cylinder are conductive components that transmit the signal in sequence, and finally reliably connect to the PCBA board. This method avoids signal loss or attenuation caused by poor single-point contact, ensures stable transmission of electrical signals between the pen tip and the motherboard, and improves the accuracy and response speed of pen tip input. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a partial cross-sectional view of the interior of this utility model; Figure 3 This is a partial three-dimensional schematic diagram of the interior of this utility model; Explanation of reference numerals in the attached figures: 2. Pen body; 1. Pen tip; 3. Gap protection cavity; 9. Fixing cylinder; 8. PCBA board; 10. Pressure sensor; 11. Force transmission sleeve; 7. Preload spring; 6. Elastic needle; 13. Syringe; 12. Support spring; 14. Conductive tube; 5. Conductive tip; 4. Pen tip cap. Detailed Implementation

[0018] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0019] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0020] like Figures 1-3 As shown, this utility model discloses a capacitive pen pressure-sensitive mechanism, the structure of which includes a pen body 2 and a pen tip 1 installed at the head of the pen body 2. A gap protection cavity 3 is formed between the pen tip 1 and the pen body 2 to ensure that the pen tip 1 has reasonable movement space during force displacement and to avoid interference between components. The pen tip 1 includes a conductive tip 5 and a pen tip 1 cap. The conductive tip 5 is fixed on the pen tip 1 cap and is used to contact the external touch screen and conduct signals. The force on the pen tip 1 is ultimately transmitted to the pressure sensor 10 through the internal structure.

[0021] An elastic pressure-sensitive mechanism is provided inside between the pen tip 1 and the pen body 2. This mechanism consists of an elastic needle 6, a syringe 13, and a support spring 12. One end of the elastic needle 6 is inserted into the conductive tip 5 and connected to it, while the other end extends into the syringe 13 and abuts against the support spring 12 inside the syringe 13.

[0022] The support spring 12 provides basic support and rebound force, enabling the elastic needle 6 to compress or retract axially when the pen tip 1 is subjected to force, thereby achieving force buffering and transmission.

[0023] When in normal use, the pressure on the pen tip 1 is transmitted step by step through the elastic needle 6 and the support spring 12 to the force transmission sleeve 11 at the rear, and then further acts on the pressure sensor 10 to detect the writing pressure.

[0024] When excessive external pressure is applied, the elastic needle 6 will retract beyond its preset elastic limit, thereby absorbing excessive stress and preventing the sensor from being damaged due to overload. This characteristic ensures the reliability and lifespan of the sensor.

[0025] The fixing cylinder 9 is located inside the pen body 2. It is made of metal and is conductive. The fixing cylinder 9 is electrically connected to the PCBA board 8 by welding, ensuring stable transmission of electrical signals. A force-transmitting sleeve 11 is installed inside the fixing cylinder 9. The force-transmitting sleeve 11 is made of non-metallic insulating material. One end contacts the force-receiving end of the pressure sensor 10, and the other end houses the elastic pressure-sensing mechanism, allowing the pressure from the pen tip 1 to be applied to the sensor via the elastic needle 6 and the support spring 12. Simultaneously, the insulating structure of the force-transmitting sleeve 11 effectively avoids metal interference signals, ensuring the accuracy of the sensor output data.

[0026] A preload spring 7 is installed between the fixed cylinder 9 and the elastic pressure sensing mechanism. The preload spring 7 is connected to both the fixed cylinder 9 and the elastic needle 6. Its function is to give the pressure sensor an initial pressure value when the pressure sensor 10 is not subjected to external force, thereby establishing a stable working reference.

[0027] With this design, when the pressure on the pen tip 1 is less than the preset value of the compression of the elastic needle 6, the elastic needle 6 will not retract, but will accurately transmit the pressure to the sensor, enabling the sensor to achieve accurate detection in the low-pressure range.

[0028] When the pressure on the pen tip 1 exceeds the preset compression value, such as 500gf, the elastic needle 6 will retract to absorb part of the overload pressure, so that the pressure received by the sensor is only within a reasonable range, thereby playing an overload protection role.

[0029] In terms of electrical signal transmission, this invention achieves step-by-step transmission of signals from the pen tip 1 through multi-stage conductive media. Specifically, the conductive tip 5 of the pen tip 1 is connected to the elastic needle 6, the elastic needle 6 is connected to the fixed cylinder 9 through the pre-compression spring 7, and the fixed cylinder 9 is connected to the PCBA board 8 through welding.

[0030] In some embodiments, a conductive tube 14 is also provided between the fixed cylinder 9 and the pen tip 1 to further ensure the continuity and stability of the signal transmission from the pen tip 1 to the PCBA board 8, and at the same time, a stroke gap cavity is formed inside it to provide buffer space for the movement of the elastic needle 6.

[0031] Ultimately, the signal input from pen tip 1 is transmitted through multiple paths, including conductive tip 5, elastic needle 6, pre-compression spring 7, and fixing cylinder 9, ensuring that the signal can be accurately and reliably delivered to the control circuit on PCBA board 8.

[0032] During operation, when the user writes with the capacitive pen, the pressure on the pen tip 1 is transmitted to the elastic needle 6 through the conductive tip 5, and then gradually transmitted to the pressure sensor 10 through the support spring 12, the preload spring 7 and the force transmission sleeve 11. The sensor detects the pressure in real time and feeds the signal back to the main control circuit.

[0033] If the pressure applied by the user is within the preset range, the elastic needle 6 will not retract, and the pressure on the pen tip 1 will be accurately transmitted to the sensor to achieve high-precision pressure sensing.

[0034] When the pressure applied by the user exceeds a preset threshold, the elastic needle 6 retracts, reducing the load on the sensor and thus providing protection. At the same time, the electrical signal from the pen tip 1 is stably transmitted through the aforementioned multi-stage conductive path, ultimately connecting reliably with the circuitry on the PCBA board 8, ensuring the integrity and accuracy of the touch input.

[0035] Therefore, by setting up a combination structure of elastic needle 6 and pre-compression spring 7 in a limited space, this utility model not only achieves stable transmission of pressure of pen tip 1, but also provides overload protection for sensor through the retraction characteristic of elastic needle 6.

[0036] Meanwhile, by using a multi-level conductive medium to conduct signals, the pen tip 1 signal can be reliably transmitted to the main control circuit, avoiding the signal instability problem existing in the prior art, thereby greatly improving the overall performance and reliability of the capacitive pen.

[0037] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope defined in the claims.

Claims

1. A capacitive pen pressure-sensitive mechanism, characterized in that, include: The pen body (2) and the pen tip (1) are mounted on the head of the pen body (2), and a gap protection cavity (3) is formed between the pen tip (1) and the pen body (2); An elastic pressure-sensitive mechanism is disposed inside between the pen tip (1) and the pen body (2) for axial displacement under a preset pressure, thereby transmitting the pressure on the pen tip (1) to the pressure sensor. A fixed cylinder (9) is fixedly connected to a PCBA board (8) installed inside the pen body (2), and the pressure sensor (10) is located on the PCBA board (8) inside the fixed cylinder (9). A force transmission sleeve (11) is installed inside the fixed cylinder (9), with one end of it in contact with the force-receiving end of the pressure sensor (10), and the elastic pressure-sensing mechanism is installed inside the force transmission sleeve (11). A preload spring (7) is disposed between the fixed cylinder (9) and the elastic pressure sensing mechanism to give the pressure sensor (10) an initial pressure value.

2. The capacitive pen pressure-sensitive mechanism according to claim 1, characterized in that: The elastic pressure-sensitive mechanism includes an elastic needle (6), a syringe (13), and a support spring (12). The support spring (12) is installed inside the syringe (13). One end of the elastic needle (6) is inserted into the pen tip (1) and communicates with the pen tip (1). The other end is inserted into the syringe (13) and contacts and supports the support spring (12).

3. The capacitive pen pressure-sensitive mechanism according to claim 2, characterized in that: The elastic needle (6) is connected to the fixed cylinder (9) through the preload spring (7), and the preload spring (7) is connected to the elastic needle (6).

4. The capacitive pen pressure-sensitive mechanism according to claim 1, characterized in that: It also includes a conductive tube (14), which is installed between the fixed cylinder (9) and the pen tip (1) to transmit the signal of the pen tip (1) to the PCBA board (8). One end of the fixed cylinder (9) is electrically connected to the PCBA board (8), and the other end forms a stroke gap cavity with the pen tip (1).

5. The capacitive pen pressure-sensitive mechanism according to claim 2, characterized in that: The pen tip (1) includes a conductive tip (5) and a pen tip (1) cap. The conductive tip (5) is mounted on the pen tip (1) cap. One end of the elastic needle (6) is inserted into the conductive tip (5) and communicates with the conductive tip (5).

6. The capacitive pen pressure-sensitive mechanism according to claim 2, characterized in that: The force transmission sleeve (11) is made of insulating non-metallic material.

7. The capacitive pen pressure-sensitive mechanism according to claim 2, characterized in that: The fixed cylinder (9) and the PCBA board (8) are electrically connected by welding.

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