CN214373019U

CN214373019U - Pressure sensing device for electronic pen and electronic pen

Info

Publication number: CN214373019U
Application number: CN202120555855.6U
Authority: CN
Inventors: 吴振宇
Original assignee: Clixup Touch Beijing Co ltd
Current assignee: Clixup Touch Beijing Co ltd
Priority date: 2021-03-18
Filing date: 2021-03-18
Publication date: 2021-10-08
Anticipated expiration: 2031-03-18

Abstract

The utility model provides a pressure sensing device for an electronic pen, the electronic pen comprises a pen head and a pen body, the pressure sensing device is arranged at the top of the pen point and comprises a magnetic part, a magnetic field detector and a pressure acquisition circuit, the magnetic part can move up and down in the pen head, the magnetic field detector is positioned above the magnetic part, and a gap is left between the magnetic field detector and the magnetic component, the magnetic field detector is used for detecting the magnetic field change in the moving process of the magnetic component, the pressure acquisition circuit is arranged in the pen body and used for acquiring voltage signals output by the magnetic field detector when the magnetic field changes, the voltage signal output end of the magnetic field detector is connected with the voltage signal input end of the pressure acquisition circuit, and the voltage signal output end of the pressure acquisition circuit outputs an amplified voltage signal. The utility model discloses can realize accurate pressure measurement.

Description

Pressure sensing device for electronic pen and electronic pen

Technical Field

The application relates to the field of electronic accessories, in particular to a pressure sensing device for an electronic pen and the electronic pen.

Background

With the improvement of the technological level and the quality of life, more and more intelligent devices appear in the daily work and life of people, and the touch device is one of the intelligent devices. People can directly operate on the display screen through the touch equipment without a mouse or other equipment for wired or wireless operation, and the operation is convenient and fast. Meanwhile, electronic pens capable of writing on touch devices have also come to light. People can write on the touch device at will like using a real pen by using an electronic pen.

In order to make the electronic pen simulate the writing feeling of a physical pen more truly, a pressure sensing module is added in the electronic pen, so that the writing handwriting output by the electronic pen changes along with the force applied by a user. However, the pressure-sensitive module of the existing electronic pen still has the problems of low sensitivity and low linearity. In addition, the pressure sensor of the conventional electronic pen is usually in direct contact with the pen point, so as to detect the pressure information transmitted from the pen point. Because the pressure sensor belongs to a very precise and fragile electronic device, the direct contact easily causes the damage of the pressure sensor, the integral reliability of the pressure sensing module is seriously influenced, and the anti-interference performance is poor.

SUMMERY OF THE UTILITY MODEL

In order to solve one of the above technical problems, the present invention provides a pressure sensing device for an electronic pen and an electronic pen.

The embodiment of the utility model provides a first aspect provides a pressure sensing device for electronic pen, electronic pen includes nib and body, the nib sets up the front end of body, the top of nib is provided with pressure sensing device, pressure sensing device includes magnetic part, magnetic field detector and pressure acquisition circuit, magnetic part can reciprocate in the nib, the magnetic field detector is located the top of magnetic part, just leave the space between magnetic field detector and the magnetic part, magnetic field detector is used for detecting the magnetic field change in the magnetic part removal process, pressure acquisition circuit sets up in the body, pressure acquisition circuit is used for gathering the voltage signal of magnetic field detector output when the magnetic field changes, the voltage signal output part of magnetic field detector with pressure acquisition circuit's voltage signal input part is connected, and the voltage signal output end of the pressure acquisition circuit outputs the amplified voltage signal.

Preferably, the device further comprises a limiting part, a conducting part and a first spring, a fixing groove is formed in the center of the top of the conducting part, a magnetic part is fixed in the fixing groove, the magnetic field detector is positioned above the magnetic part, a gap is reserved between the magnetic part and the magnetic field detector, the outer side wall of the conducting part protrudes outwards to form a boss, the first spring is sleeved outside the conducting part, one end of the first spring is fixedly connected with the top surface of the boss, the other end of the first spring is fixedly connected with the bottom surface of the conducting plate, an insertion groove is formed in the center of the bottom of the conducting part along the length direction of the conducting part, the tail end of the pen head is inserted into the insertion groove, the front end of the pen head is exposed outside the conducting part, and the limiting part is sleeved outside the conducting part, the inner side wall of the limiting part protrudes inwards to form a convex ring, and the inner diameter of the convex ring is smaller than the outer diameter of the boss.

Preferably, the initial state of the first spring is a compressed state, and when the first spring is in the initial state, the bottom surface of the boss is in contact with the top surface of the convex ring.

Preferably, the pen point further comprises a second spring, the second spring is sleeved outside the conduction portion, one end of the second spring is fixedly connected with the bottom surface of the boss, and the other end of the second spring is fixedly connected with the top surface of the convex ring.

Preferably, the middle section of the boss is recessed inwards to form a recessed area, a partial area of the recessed area is communicated with the insertion groove in the conduction part, a fastening part is arranged in the recessed area, and the fastening part is tightly matched with the pen point in the insertion groove of the conduction part.

Preferably, the pressure acquisition circuit includes acquisition circuit, reference circuit, differential circuit and amplifier circuit, the voltage signal output of magnetic field detector with acquisition circuit's voltage signal input end is connected, acquisition circuit's voltage signal output with differential circuit's first voltage signal input end is connected, reference circuit's voltage signal output with differential circuit's second voltage signal input end is connected, differential circuit's voltage signal output with amplifier circuit's voltage signal input end is connected, amplifier circuit's voltage signal output end exports the voltage signal after the amplification.

Preferably, the device further comprises a processor, a voltage signal input end of the processor is connected with a voltage signal output end of the pressure acquisition circuit, and a pressure signal output end of the processor outputs pressure information.

The embodiment of the utility model provides an electronic pen is provided to the second aspect, electronic pen includes the embodiment of the utility model provides the first aspect pressure sensing device.

Preferably, the electronic pen further comprises an inner frame, the inner frame is arranged in the pen body, the outer side wall of the inner frame is tightly matched with the inner side wall of the pen body, the front end of the inner frame is fixedly connected with the tail end of the pressure sensing device, and the pressure acquisition circuit is arranged in the inner frame.

The utility model has the advantages as follows: the utility model discloses a magnetic field detector detects the characteristic in the produced magnetic field of magnetic part in the middle of the up-and-down motion process to output the magnitude of voltage when magnetic part is located different positions, and then turn into the pressure value with this magnitude of voltage, thereby realize accurate pressure measurement. The utility model discloses in, magnetic part is at the motion device, does not take place any contact between magnetic field detector and the magnetic part, and the pressure through non-contact detects the influence of having eliminated the device damage and causing, has improved the reliability and the interference immunity that the pressure detected.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural diagram of a pressure sensing device for an electronic pen according to embodiment 1 of the present invention;

fig. 2 is another schematic structural diagram of a pressure sensing device for an electronic pen according to embodiment 1 of the present invention;

fig. 3 is a schematic diagram of a pressure acquisition circuit according to embodiment 1 of the present invention;

fig. 4 is a circuit diagram of a pressure acquisition circuit according to embodiment 1 of the present invention;

fig. 5 is a circuit diagram of the acquisition circuit according to embodiment 1 of the present invention;

fig. 6 is a circuit diagram of a reference circuit according to embodiment 1 of the present invention;

fig. 7 is a circuit diagram of a differential circuit according to embodiment 1 of the present invention;

fig. 8 is a circuit diagram of an amplifying circuit according to embodiment 1 of the present invention;

fig. 9 is a schematic overall appearance diagram of a pressure sensing device for an electronic pen according to embodiment 2 of the present invention;

fig. 10 is a schematic structural diagram of a pressure sensing device for an electronic pen according to an embodiment of the present invention applied to a capacitance pen;

fig. 11 is another schematic structural diagram of the pressure sensing device for an electronic pen according to an embodiment of the present invention applied to a capacitance pen.

Reference numerals:

1. the pen comprises a pen point, 2, a limiting part, 3, an emitting part, 4, a conducting part, 5, a conducting plate, 6, a first spring, 7, a magnetic part, 8, a magnetic field detector, 9, a boss, 10, a convex ring, 11, a second spring, 12, a fastening part, 13 and a pen body.

Detailed Description

In order to make the technical solutions and advantages of the embodiments of the present application more apparent, the following further detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings makes it clear that the described embodiments are only a part of the embodiments of the present application, and are not exhaustive of all embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. Moreover, in order to provide a clearer description and easier understanding of the present application, the parts in the drawings are not drawn according to their relative dimensions, some dimensions have been exaggerated compared to other relevant dimensions; irrelevant details are not fully drawn for the sake of brevity.

Example 1

As shown in fig. 1, the present embodiment provides a pressure sensing device for an electronic pen, the electronic pen includes a pen point 1 and a pen body 13, the pen point 1 is disposed at a front end of the pen body 13, the pressure sensing device is disposed at a top of the pen point 1, the pressure sensing device includes a magnetic component 7, a magnetic field detector 8 and a pressure collecting circuit, the magnetic component 7 is movable up and down inside the pen point 1, the magnetic field detector 8 is located above the magnetic component 7, a gap is left between the magnetic field detector 8 and the magnetic component 7, the magnetic field detector 8 is configured to detect a magnetic field change during a movement process of the magnetic component 7, the pressure collecting circuit is disposed inside the pen body 13, the pressure collecting circuit is configured to collect a voltage signal output by the magnetic field detector 8 when the magnetic field changes, and the voltage signal output end of the magnetic field detector 8 is connected with the voltage signal input end of the pressure acquisition circuit, and the voltage signal output end of the pressure acquisition circuit outputs an amplified voltage signal.

Specifically, the device provided in this embodiment further includes a limiting portion 2, a conducting portion 4, and a first spring 6, wherein a fixing groove is formed in the center of the top of the conducting portion 4, and a magnetic component 7 is disposed in the fixing groove. The magnetic member 7 may be any substance having magnetism, such as a magnet. A gap is left between the magnetic field detector 8 and the magnetic member 7. The magnetic field detector 8 can detect the magnetic field change of the magnetic component 7 during the movement. In this embodiment, the magnetic field detector 8 may be a hall effect sensor, which can realize non-contact detection of pressure, and has the characteristics of fast response speed, high measurement accuracy, and good linearity. Therefore, when the front end of the pen point 1 is in contact with an external object and is forced to move upwards or downwards due to loss of the force, the magnetic component 7 is driven by the conduction part 4 to move upwards or downwards, so that the relative position between the magnetic component 7 and the magnetic field detector 8 is changed. In this way, the magnetic field information detected by the magnetic field detector 8 when the magnetic member 7 is changed in position is different, so that the signals output from the magnetic field detector 8 are also different. Therefore, the present embodiment outputs different signals corresponding to the pressure values according to the magnetic field changes by the magnetic field detector 8 to realize the detection of the pressure. For example, when the magnetic component 7 and the magnetic field detector 8 are spaced apart by 0.5mm, the corresponding pressure value is 100N; when the distance between the magnetic member 7 and the magnetic field detector 8 is 0.1mm, the corresponding pressure value is 300N. Therefore, when the user uses the electronic pen to operate on the touch screen, corresponding pressure values can be generated, and then the corresponding writing track effects in different pressure states can be presented on the touch screen.

In this embodiment, the first spring 6 can play a role of signal transmission, and can be compressed when the pen point 1 is forced to move upwards, and acts reversely on the conducting portion 4 when the pen point 1 loses the force in the process of moving upwards, so that the pen point 1 returns to the initial position, and normal use of a user is realized. In order to make the up-and-down movement of the conducting part 4 in the position-limiting part 2 more stable, the present embodiment is provided with a convex ring 10 on the inner side wall of the position-limiting part 2, and the convex ring 10 is formed by the inner side wall of the position-limiting part 2 protruding inwards. The protruding ring 10 is located below the boss 9 of the conducting part 4, and the inner diameter of the protruding ring 10 is ensured to be smaller than the outer diameter of the boss 9. When the conduction part 4 moves downwards, the conduction part 4 is limited to continue to move downwards due to the blocking effect of the convex ring 10, so that the conduction part 4 is positioned and stabilized. In addition, when the pen point 1 is not acted by external force and is in the initial position, the initial state of the first spring 6 is a compressed state, and meanwhile, the bottom surface of the boss 9 is ensured to be in contact with the top surface of the convex ring 10. In this way, the stability of the movement of the conducting part 4 in the limiting part 2 is ensured by the compressed state of the first spring 6 and the structural features of the protruding ring 10 and the boss 9 interfering with each other.

In addition, normally, the effective connection between the pen point 1 and the conduction part 4 is realized by the friction force between the outer wall of the pen point 1 and the inner wall of the conduction part 4, so that the pen point 1 does not loosen or misplace in the conduction part 4. However, in actual use, the friction between the nib 1 and the conductive portion 4 is inevitably reduced due to the continuous stress on the nib 1 and the loosening of the structural parts caused during long-term use. In order to prevent the pen point 1 and the conduction part 4 from loosening or dislocation, the middle section of the boss 9 is first recessed to form a recessed area. A part of the area of the recess is connected to the plug groove in the interior of the conducting part 4. Then, a fastening part 12 is arranged in the concave area, and the fastening part 12 can be tightly matched with the pen point 1 positioned in the inserting groove of the conduction part 4. The fastening portion 12 may be a flexible object, such as a rubber band or rubber band, which can "bind" the pen head 1 and the conductive portion 4.

Further, in the present embodiment, since the first spring 6 is in the compressed state in the initial state, the first spring 6 applies a downward force to the conduction part 4 in the compressed state. If the pressure generated when the front end of the pen point 1 contacts with the external equipment is smaller than the downward force applied to the conduction part 4 by the first spring 6, the pen point 1 cannot move upwards. The gap between the magnetic means 7 and the magnetic field detector 8 does not change either, resulting in the electronic pen now assuming a "no pressure output" state. However, at this time, contact between the nib 1 and the external device is already established and pressure is generated, which does not guarantee a pressure output at the instant when the nib 1 is in contact with the external device. In order to solve this drawback, the present embodiment further provides a second spring 11 between the convex ring 10 and the boss 9, and the second spring 11 is sleeved outside the conductive part 4. The second spring 11 is used for counteracting the downward force applied to the conduction part 4 by the first spring 6 in the initial state, so that the pen point 1 can move upwards at the moment when the pen point 1 is in contact with external equipment, the distance between the magnetic component 7 and the magnetic field detector 8 is changed, and a correct pressure value can be output. In order to counteract the downward force applied by the first spring 6 to the conduction part 4 in the initial state, the spring constant of the first spring 6 is preferably the same as that of the second spring 11, and the initial state of the first spring 6 is ensured to be the same as that of the second spring 11, i.e., the same amount of compression. Of course, the present embodiment does not exclude the case where the characteristic parameters of the first spring 6 and the second spring 11 are different, as long as the second spring 11 can cancel the downward force applied to the conduction part 4 by the first spring 6 in the initial state. In addition, the length and the hardness of the initial state of the first spring 6 can be adjusted, so that the stroke of the magnetic component 7 moving up and down is adjusted, and more flexible pressure detection is realized.

In addition, this embodiment adopts the structure of dual spring, except can guaranteeing pressure output's instantaneity and accuracy, still can play the cushioning effect among the power transmission process because the elasticity of spring realizes the effect of amortization, avoids nib 1 to produce great noise when contacting with external equipment to improve user's use and experience.

Further, as shown in fig. 3 and 4, the pressure acquisition circuit specifically includes an acquisition circuit, a reference circuit, a differential circuit, and an amplification circuit, a voltage signal output terminal of the magnetic field detector 8 is connected to a voltage signal input terminal of the acquisition circuit, a voltage signal output terminal of the acquisition circuit is connected to a first voltage signal input terminal of the differential circuit, a voltage signal output terminal of the reference circuit is connected to a second voltage signal input terminal of the differential circuit, a voltage signal output terminal of the differential circuit is connected to a voltage signal input terminal of the amplification circuit, and a voltage signal output terminal of the amplification circuit outputs an amplified voltage signal.

In this embodiment, the collecting circuit of the pressure collecting circuit may collect the voltage signal output by the magnetic field detector 8, output a voltage signal linearly variable with the voltage signal according to the voltage signal, and then send the voltage signal to the differential circuit as one input signal of the differential circuit.

The reference circuit may be configured to output a reference voltage as another input signal of the differential circuit. In the differential circuit, the difference between the voltage output by the acquisition circuit and the reference voltage is calculated to obtain a difference voltage. And finally, amplifying the difference voltage by N times through an amplifying circuit and outputting the amplified difference voltage to a processor for subsequent processing. The processor can be an electronic device with a logic processing function, such as a singlechip, an FPGA and the like.

In the above process, when the magnetic field detector 8 detects the magnetic field change caused by the position change of the magnetic component 7, a voltage signal is output, and the acquisition circuit acquires and outputs the voltage signal, for example, 0.5V. Meanwhile, the reference circuit is configured to output a 0.6V voltage, and then the differential circuit performs differential calculation to output a 0.1V differential voltage. Assuming that the amplification factor of the amplification circuit is set to 10 times, the amplification circuit finally outputs an amplification voltage of 1V. When the magnetic member 7 is closer to the magnetic field detector 8, the voltage value of the output collected by the collection circuit may be 0.6V. Then the amplified voltage of 2V is output after being processed by the differential circuit and the amplifying circuit. It can be seen that, after passing through the pressure acquisition circuit of the present embodiment, the change amount of the voltage value output by the magnetic field detector 8 is amplified from 0.1V to 1V. Therefore, the voltage value received by the processor and the change amplitude of the voltage are larger, the processor can more accurately identify the slight pressure change, and further more levels of pressure detection are realized.

Specifically, as shown in fig. 5, the acquisition circuit includes a first resistor R1, a second resistor R2, and a first capacitor C1, two ends of the first resistor R1 are connected to the pressure signal input terminal of the acquisition circuit and the pressure signal output terminal of the pressure sensing chip M1, one end of the first resistor R1 is connected to the power supply, the other end of the first resistor R1 is connected to one end of the first capacitor C1, one end of the second resistor R2, and the first voltage signal input terminal of the differential circuit, and the other end of the first capacitor C1 is connected to the other end of the second resistor R2 and grounded.

As shown in fig. 6, the reference circuit includes a third resistor R3, a fourth resistor R4, a second capacitor C2, a third capacitor C3, and a first operational amplifier U1, one end of the third resistor R3 is connected with a power supply, the other end of the third resistor R3 is simultaneously connected with one end of the fourth resistor R4 and the non-inverting input end of the first operational amplifier U1, the other end of the fourth resistor R4 is grounded, the power supply end of the first operational amplifier U1 is simultaneously connected with one end of the second capacitor C2, one end of the third capacitor C3 and the power supply, the other end of the second capacitor C2 is connected to the other end of the third capacitor C3 and to ground, the ground terminal of the first operational amplifier U1 is grounded, and the output terminal of the first operational amplifier U1 is used as the voltage signal output terminal of the reference circuit and is connected to the inverting input terminal of the first operational amplifier U1 and the second voltage signal input terminal of the differential circuit.

As shown in fig. 7, the differential circuit includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a fourth capacitor C4, a fifth capacitor C5, a diode D1, and a second operational amplifier U2, one end of the fifth resistor R5 is connected to the voltage signal output terminal of the acquisition circuit as the first voltage signal input terminal of the differential circuit, the other end of the fifth resistor R5 is connected to the inverting input terminal of the second operational amplifier U2 and one end of the eighth resistor R8, one end of the sixth resistor R6 is connected to the voltage signal output terminal of the reference circuit as the second voltage signal input terminal of the differential circuit, the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and the non-inverting input terminal of the second operational amplifier U2, and the output terminal of the second operational amplifier U2 is connected to the voltage signal input terminal of the differential circuit as the voltage signal output terminal of the differential circuit and the voltage signal input terminal of the eighth resistor R8 and the non-inverting input terminal of the second operational amplifier U2, and the output terminal of the differential amplifier U2 are connected to the voltage signal output terminal of the differential circuit as the voltage signal output terminal of the differential circuit The power supply terminal of the second operational amplifier U2 is connected to the negative electrode of the diode D1, the one end of the fourth capacitor C4, the one end of the fifth capacitor C5 and the power supply at the same time, the positive electrode of the diode D1 is connected to the power supply, the other end of the fourth capacitor C4 is connected to the other end of the fifth capacitor C5 and grounded, and the ground terminal of the second operational amplifier U2 is grounded.

As shown in fig. 8, the amplifying circuit includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a sixth capacitor C6, and a third operational amplifier U3, a non-inverting input terminal of the third operational amplifier U3 is connected to the voltage signal output terminal of the differential circuit as a voltage signal input terminal of the amplifying circuit, an inverting input terminal of the third operational amplifier U3 is connected to one end of the ninth resistor R9 and one end of the tenth resistor R10 at the same time, the other end of the ninth resistor R9 is connected to the output terminal of the third operational amplifier U3 and one end of the twelfth resistor R12 at the same time, the other end of the twelfth resistor R12 is connected to one end of the thirteenth resistor R13 and one end of the sixth capacitor C6 as a voltage signal output terminal of the amplifying circuit at the same time and outputs an amplified voltage signal, the other end of the thirteenth resistor R13 is connected to the other end of the sixth capacitor C6 and grounded, the other end of the tenth resistor R10 is connected to one end of an eleventh resistor R11, and the other end of the eleventh resistor R11 is grounded.

Example 2

As shown in fig. 9, this embodiment provides an electronic pen, which includes the pressure sensing device provided in embodiment 1, and the specific operation principle and structural composition of the pressure sensing device are not described herein again. The electronic pen proposed in this embodiment further includes an inner frame disposed in the pen body 13. The inner frame and the pen body 13 can be connected in a tight fit manner, so that the inner frame and the pen body can be conveniently mounted and dismounted. The pen point 1 is arranged at the front end of the pen body 13, and the tail end of the pen point 1 is fixedly connected with the front end of the inner frame. The connection mode may be a snap connection or a bolt connection, and the embodiment is not particularly limited. The inner frame is loaded with a circuit board, and electronic devices and circuit structures such as a pressure acquisition circuit and a processor are welded on the circuit board so as to ensure the stability of the electronic devices and the circuit structures in the electronic pen.

The practical application of the pressure sensing device in the middle of the capacitance pen is taken as an example to illustrate the specific use mode and the working principle of the pressure sensing device of the present invention.

As shown in fig. 9 to 11, the present embodiment provides a capacitive pen, which includes a pen point 1, a pen body 13, and a pressure acquisition circuit, where the pen point 1 is disposed at a front end of the pen body 13. Wherein, the pressure sensing device comprises a limiting part 2, a transmission part 4 and a first spring 6. Besides, the capacitive stylus also includes an emitting portion 3 and a conductive plate 5. Specifically, the pen point 1, the limiting part 2, the emitting part 3, the conducting part 4, the conducting plate 5 and the first spring 6 are all made of conducting materials. The center of the bottom of the conduction part 4 is provided with a plug-in slot along the length direction of the conduction part 4. The pen point 1 can be inserted into the insertion groove to realize the tight fit connection between the conduction part 4 and the pen point 1. The tip 1 is partially exposed to the outside of the conductive portion 4. The outer side wall of the conducting part 4 protrudes outwards forming a boss 9.

A fixing groove is formed at the center of the top of the conducting part 4, and a magnetic part 7 is arranged in the fixing groove. The magnetic member 7 may be any substance having magnetism, such as a magnet. An electrically conductive plate 5 is provided above the magnetic member 7, and a gap is left between the magnetic member 7 and the electrically conductive plate 5. A signal line connected to an external circuit may extend from the conductive plate 5. A first spring 6 is provided between the conductive plate 5 and the recessed land of the conductive part 4, and the first spring 6 is fitted over the conductive part 4. Thus, the nib 1, the conductive part 4, the first spring 6 and the conductive plate 5 form a signal transmission path. The pen point 1 receives signals sent by external equipment, and the signals are transmitted through the conducting part 4 and the first spring 6 and finally sent to a subsequent circuit by the conducting plate 5 for processing. A magnetic field detector 8 is provided on the conductive plate 5. The magnetic field detector 8 can detect the magnetic field change of the magnetic component 7 during the movement.

The conducting part 4 is also sleeved with a limiting part 2, and the conducting part 4, the first spring 6 and most parts of the pen point 1 except the front end part are all covered in the limiting part 2. When the pen point 1 is subjected to external force or loses the external force, the conducting part 4 can move up and down in the limiting part 2. The transmitting part 3 is sleeved outside the limiting part 2, and the transmitting part 3 can be a conductive spring wound on the outer side wall of the limiting part 2. A signal line connected to an external circuit also extends from the transmitter 3. The conductive plate 5 transmits the signal received by the pen point 1 to a subsequent circuit for processing, and then the processed signal can be transmitted to an external device through the transmitting part 3, so that a complete signal transmission route is formed. The limiting part 2 can completely isolate the signals received by the pen point 1 from the signals sent out, and ensure that the signals are not interfered by each other.

Further, in the present embodiment, since the first spring 6 is in the compressed state in the initial state, the first spring 6 applies a downward force to the conduction part 4 in the compressed state. If the pressure generated when the front end of the pen point 1 contacts with the external equipment is smaller than the downward force applied to the conduction part 4 by the first spring 6, the pen point 1 cannot move upwards. The gap between the magnetic means 7 and the magnetic field detector 8 does not change either, resulting in the capacitive stylus now assuming a "no pressure output" condition. However, at this time, contact between the nib 1 and the external device is already established and pressure is generated, which does not guarantee a pressure output at the instant when the nib 1 is in contact with the external device. In order to solve this drawback, the present embodiment further provides a second spring 11 between the convex ring 10 and the boss 9, and the second spring 11 is sleeved outside the conductive part 4. The second spring 11 is used for counteracting the downward force applied to the conduction part 4 by the first spring 6 in the initial state, so that the pen point 1 can move upwards at the moment when the pen point 1 is in contact with external equipment, the distance between the magnetic component 7 and the magnetic field detector 8 is changed, and a correct pressure value can be output. In order to counteract the downward force applied by the first spring 6 to the conduction part 4 in the initial state, the spring constant of the first spring 6 is preferably the same as that of the second spring 11, and the initial state of the first spring 6 is ensured to be the same as that of the second spring 11, i.e., the same amount of compression.

The utility model discloses a magnetic field detector detects the characteristic in the produced magnetic field of magnetic part in the middle of the up-and-down motion process to output the magnitude of voltage when magnetic part is located different positions, and then turn into the pressure value with this magnitude of voltage, thereby realize accurate pressure measurement. The utility model discloses in, magnetic part is at the motion device, does not take place any contact between magnetic field detector and the magnetic part, and the pressure through non-contact detects the influence of having eliminated the device damage and causing, has improved the reliability and the interference immunity that the pressure detected.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A pressure sensing device for an electronic pen, the electronic pen comprises a pen point and a pen body, the pen point is arranged at the front end of the pen body, the pressure sensing device is arranged at the top of the pen point and comprises a magnetic part, a magnetic field detector and a pressure acquisition circuit, the magnetic part can move up and down in the pen point, the magnetic field detector is positioned above the magnetic part, a gap is reserved between the magnetic field detector and the magnetic part, the magnetic field detector is used for detecting the magnetic field change in the moving process of the magnetic part, the pressure acquisition circuit is arranged in the pen body and is used for acquiring a voltage signal output by the magnetic field detector when the magnetic field changes, and the voltage signal output end of the magnetic field detector is connected with the voltage signal input end of the pressure acquisition circuit, and the voltage signal output end of the pressure acquisition circuit outputs the amplified voltage signal.

2. The device of claim 1, further comprising a position-limiting portion, a conducting portion and a first spring, wherein a fixing groove is formed in the center of the top of the conducting portion, a magnetic member is fixed in the fixing groove, a gap is formed between the magnetic member and the magnetic field detector, the outer side wall of the conducting portion protrudes outwards to form a boss, the first spring is sleeved outside the conducting portion, one end of the first spring is fixedly connected with the top surface of the boss, the other end of the first spring is fixedly connected with the bottom surface of the conducting plate, an insertion groove is formed in the center of the bottom of the conducting portion along the length direction of the conducting portion, the tail end of the pen head is inserted into the insertion groove, the front end of the pen head is exposed outside the conducting portion, and the position-limiting portion is sleeved outside the conducting portion, the inner side wall of the limiting part protrudes inwards to form a convex ring, and the inner diameter of the convex ring is smaller than the outer diameter of the boss.

3. The apparatus of claim 2, wherein the initial state of the first spring is a compressed state, and wherein the bottom surface of the boss is in contact with the top surface of the raised ring when the first spring is in the initial state.

4. The device of claim 3, wherein the pen point further comprises a second spring, the second spring is sleeved outside the conducting portion, one end of the second spring is fixedly connected with the bottom surface of the boss, and the other end of the second spring is fixedly connected with the top surface of the convex ring.

5. The device of claim 2, wherein the middle section of the boss is recessed inwards to form a recessed area, a partial area of the recessed area is communicated with the insertion groove in the conduction part, and a fastening part is arranged in the recessed area and is tightly matched with the pen point in the insertion groove of the conduction part.

6. The device of claim 1, wherein the pressure acquisition circuit comprises an acquisition circuit, a reference circuit, a differential circuit and an amplification circuit, the voltage signal output terminal of the magnetic field detector is connected to the voltage signal input terminal of the acquisition circuit, the voltage signal output terminal of the acquisition circuit is connected to the first voltage signal input terminal of the differential circuit, the voltage signal output terminal of the reference circuit is connected to the second voltage signal input terminal of the differential circuit, the voltage signal output terminal of the differential circuit is connected to the voltage signal input terminal of the amplification circuit, and the voltage signal output terminal of the amplification circuit outputs an amplified voltage signal.

7. The device of claim 6, further comprising a processor, wherein a voltage signal input of the processor is connected to a voltage signal output of the pressure acquisition circuit, and a pressure signal output of the processor outputs pressure information.

8. An electronic pen, characterized in that it comprises a pressure sensing device according to any one of claims 1 to 7.

9. The electronic pen according to claim 8, further comprising an inner frame, wherein the inner frame is disposed in the pen body, an outer side wall of the inner frame is tightly fitted with an inner side wall of the pen body, a front end of the inner frame is fixedly connected with a tail end of the pressure sensing device, and the pressure acquisition circuit is disposed in the inner frame.