Handwriting input pen and handwriting device
By using a pressure sensor composed of a varistor, the existing stylus has solved the problem of high component accuracy requirements, low-cost and high-precision writing pressure detection is achieved, and the writing experience and stability of handwriting restoration is improved.
Patent Information
- Application Number
- CN202422123817.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2025-07-11
- Estimated Expiration
- 2034-08-29
AI Technical Summary
Existing stylus have high requirements for component accuracy, resulting in high costs and susceptibility to external environment interference.
A pressure sensor composed of a varistor is used to sense the writing pressure by detecting the change in voltage difference at the output terminal, reducing the requirements for resistance accuracy, and improving stability and measurement accuracy.
It realizes high-precision detection of writing pressure under low-cost conditions, improves the stability of writing experience and handwriting restoration, and reduces interference to the external environment.
Smart Images
Figure CN223092395U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of handwriting input, and particularly relates to a handwriting input pen and a handwriting device. Background Art
[0002] With the progress of technology, digital electronic information input devices already have the function of trajectory input. The realization of this function usually adopts the way of handwriting input, and the writing pressure is detected to restore the thickness and lightness of the handwriting, so as to improve the use feeling.
[0003] Please refer to Figure 1 , which is a schematic diagram of the connection structure of a writing pen provided by the prior art. The handwriting pen 20 of the prior art includes a variable capacitor 21, a processor 22, a timer 23, a resonant switch circuit 24, a resonant circuit 25 and a rectifier filter circuit 26. The capacitance value Cx of the variable capacitor 21 changes with the pressure received during writing. At the same time, the variable capacitor 21 and a resistor are connected in parallel to form a discharge circuit. The processor 22 controls the variable capacitor 21 to charge and discharge periodically, and the timer 23 records the discharge time of the variable capacitor.
[0004] The discharge time constant τ of the variable capacitor is τ = R * Cx, where R is the resistance value of the resistor connected in parallel with the variable capacitor 21. It can be seen that the discharge time of the variable capacitor 21 has a corresponding relationship with the pressure received by the pen tip. According to the discharge time of the variable capacitor 21, the magnitude of the pressure received by the handwriting pen 20 can be correspondingly judged, and then the magnitude of the pressure received by the handwriting pen 20 can be reflected on the written handwriting according to the length of the discharge time, so as to realize the change of the thickness, lightness and urgency of the written handwriting.
[0005] However, the sensitivity of the handwriting pen 20 to feedback the thickness of the handwriting is related to the accuracy of the variable capacitor 21. The capacitance value of the variable capacitor 21 needs to have a specific effective change range. Therefore, the prior art handwriting pen 20 has high requirements for the accuracy of components. Summary of the Utility Model
[0006] In order to solve the technical problem that the prior handwriting pen has high requirements for the accuracy of components, the utility model provides a handwriting input pen and a handwriting device that reduce the requirements for the accuracy of components.
[0007] A handwriting input pen includes a pen tip, a pressure sensor, and a processing circuit. The pen tip is used for writing to generate pressure. The pressure sensor senses the pressure transmitted by the pen tip and includes a first resistor, a second resistor, a third resistor, and a fourth resistor. The first ends of the first resistor and the second resistor are connected to a second output terminal. The second ends of the second resistor and the third resistor are grounded. The first ends of the third resistor and the fourth resistor are connected to a first output terminal. The second ends of the fourth resistor and the first resistor are connected to a power supply voltage. Among them, at least one of the first resistor, the second resistor, the third resistor, and the fourth resistor is a varistor. The processing circuit is connected to the first output terminal and the second output terminal, and the voltage difference between the first output terminal and the second output terminal changes with the change of pressure.
[0008] In some embodiments, the voltage difference between the first output terminal and the second output terminal is linearly related to the pressure received by the pressure sensor.
[0009] In some embodiments, the first resistor, the second resistor, the third resistor, and the fourth resistor are all varistors.
[0010] In some embodiments, the resistance values of the first resistor, the second resistor, the third resistor, and the fourth resistor are equal. Among them, the first resistor and the third resistor are varistors whose resistance values increase synchronously when stressed, and the second resistor and the fourth resistor are varistors whose resistance values decrease synchronously when stressed, and the increase amplitude and the decrease amplitude are equal. Or, the first resistor and the third resistor are varistors whose resistance values decrease synchronously when stressed, and the second resistor and the fourth resistor are varistors whose resistance values increase synchronously when stressed, and the increase amplitude and the decrease amplitude are equal.
[0011] In some embodiments, the first resistor and the second resistor are varistors with equal resistance values, and the third resistor and the fourth resistor are fixed resistors with equal resistance values. Among them, the first resistor is a varistor whose resistance value increases when stressed, and the second resistor is a varistor whose resistance value decreases when stressed, and the increase amplitude and the decrease amplitude are equal. Or, the first resistor is a varistor whose resistance value decreases when stressed, and the second resistor is a varistor whose resistance value increases when stressed, and the increase amplitude and the decrease amplitude are equal.
[0012] In some embodiments, the second resistor and the fourth resistor are fixed resistors with equal resistance values, and the first resistor and the third resistor are varistors with equal resistance values, and their resistance values increase or decrease synchronously when stressed.
[0013] In some embodiments, the processing circuit includes a signal amplifier, the first output terminal is connected to the first input terminal of the signal amplifier, and the second output terminal is connected to the second input terminal of the signal amplifier.
[0014] In some embodiments, the processing circuit includes an encoder, the encoder is connected to the output terminal of the signal amplifier, and is configured to encode the voltage difference signal between the first output terminal and the second output terminal into a digital signal.
[0015] In some embodiments, the processing circuit further includes a processor and a transmitting unit connected in series, the encoder is connected to the control unit, and the processor is configured to control the transmitting unit to transmit the digital signal.
[0016] In some embodiments, the transmitting unit includes an LC resonant circuit.
[0017] A handwriting device includes a handwriting input pen and a handwriting sensing device used in cooperation. The handwriting input pen includes a pen tip, a pressure sensor, and a processing circuit. The pen tip is used for writing to generate pressure, and the pressure sensor senses the pressure transmitted by the pen tip. The pressure sensor includes a first resistor, a second resistor, a third resistor, and a fourth resistor. The first ends of the first resistor and the second resistor are connected to a first terminal, the second ends of the second resistor and the third resistor are connected and connected to a second terminal, the first ends of the third resistor and the fourth resistor are connected to a third terminal, and the second ends of the fourth resistor and the first resistor are connected to a fourth terminal. Wherein, the first terminal is connected to the second output terminal, the second terminal is grounded, the third terminal is connected to the first output terminal, the fourth terminal is connected to a power supply voltage, and at least one of the first resistor, the second resistor, the third resistor, and the fourth resistor is a varistor. The processing circuit is connected to the first output terminal and the second output terminal, and the voltage difference between the first output terminal and the second output terminal changes with the pressure.
[0018] Compared with the prior art, the handwriting input pen provided by the present utility model is provided with a sensor to sense the pressure generated by the pen core during writing. The pressure sensor includes a first resistor, a second resistor, a third resistor, and a fourth resistor. The first ends of the first resistor and the second resistor are connected to a second output terminal. The second ends of the second resistor and the third resistor are grounded. The first ends of the third resistor and the fourth resistor are connected to a first output terminal. The second ends of the fourth resistor and the first resistor are connected to a power supply voltage. At least one of the first resistor, the second resistor, the third resistor, and the fourth resistor is a piezoresistor. By detecting the change in the voltage difference between the first output terminal and the second output terminal, the change in the writing pressure can be detected. The voltage difference is calculated based on resistor voltage division. The specific resistance values of each resistor do not need to be set to specific values, the requirement for resistor accuracy is low, and it can maintain good stability, is not easily interfered by external environmental factors, and has good consistency. At the same time, it has a high measurement accuracy and can truly restore the writing handwriting, thereby improving the writing experience.
[0019] In addition, the pressure sensor composed of the first resistor, the second resistor, the third resistor, and the fourth resistor has a lower cost compared with a high-precision variable capacitor used for detecting pressure. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0021] Figure 1 FIG. is a schematic connection structure diagram of a writing pen provided by the prior art;
[0022] Figure 2 FIG. is a schematic structure diagram of a handwriting input pen provided by the present utility model;
[0023] Figure 3 For Figure 2 FIG. is a schematic circuit connection diagram of the handwriting input pen shown;
[0024] Figure 4 For Figure 3 FIG. is a relationship curve between the voltage difference output by the pressure sensor shown and the pressure;
[0025] Figure 5 For Figure 3 FIG. is another schematic connection diagram of the pressure sensor shown;
[0026] Figure 6 For Figure 3Another connection schematic diagram of the pressure sensor shown. Detailed implementation manners
[0027] The technical solutions in the embodiments of the present utility model will be described clearly and completely below. Apparently, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.
[0028] The terms used in the embodiments of the present utility model are only for the purpose of describing specific embodiments, and are not intended to limit the present utility model. The singular forms "a" and "the" used in the embodiments of the present utility model and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.
[0029] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of the present utility model, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.
[0030] It should be understood that when an element is referred to as being "connected", "coupled", "mated", "attached", "fixed", "abutted" etc. to another element, it can be directly connected to the other element, or there may be an indirect connection. On the contrary, when an element is referred to as being "directly connected", "directly coupled" etc. to another element, there is no intermediate element. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.).
[0031] The present utility model provides a handwriting device, which includes a handwriting input pen 10 and a handwriting sensing device used in a matching manner. The handwriting input pen 10 is used for writing on the handwriting sensing device, and the handwriting sensing device may specifically be a handwriting board, a handwriting screen, etc.
[0032] Please refer to Figure 2, which is a schematic structural diagram of a handwriting input pen provided by the present utility model. The handwriting input pen 10 includes a housing 11, a pen core 12, a pressure sensor 14 and a processing circuit 15. The housing 11 partially houses the pen core 12 and houses the pressure sensor 14 and the processing circuit 15. One end of the pen core 12 is used for contacting and writing on the handwriting sensing device to generate pressure. The pressure sensor 14 abuts against the other end of the pen core 12 to sense the pressure transmitted by the pen core 12 and generate a pressure signal. The processing circuit 15 is connected to the pressure sensor 14, receives the pressure signal of the pressure sensor 14, and sends a digital signal to the handwriting sensing device according to the pressure signal.
[0033] Please refer to Figure 3 , which is Figure 2 a schematic circuit connection diagram of the handwriting input pen shown. The pressure sensor 14 includes a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4. The first ends of the first resistor R1 and the second resistor R2 are connected to the second output terminal Vout2. The second ends of the second resistor R2 and the third resistor R3 are grounded to GND. The first ends of the third resistor R3 and the fourth resistor R4 are connected to the first output terminal Vout1. The second ends of the fourth resistor R4 and the first resistor R1 are connected to the power supply voltage Vdd. At least one of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is a varistor.
[0034] The calculation formula for the voltage difference Vout between the first output terminal Vout1 and the second output terminal Vout2 is:
[0035]
[0036] It can be seen therefrom that the voltage difference Vout changes with the change of the resistance value of the varistor. By detecting the change of the voltage difference Vout, the change of the writing pressure can be detected.
[0037] In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all varistors. The resistance values of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are equal. When stressed, the resistance values of the first resistor R1 and the third resistor R3 increase synchronously, and the resistance values of the second resistor R2 and the fourth resistor R4 decrease synchronously, and the increase amplitude ΔR1 and the decrease amplitude ΔR2 are equal. The voltage difference Vout is completely linearly related to the pressure received by the pressure sensor 14, as shown in Figure 4 .
[0038] It can be understood that the first resistor R1 and the third resistor R3 can also be set as varistors whose resistance values decrease synchronously when stressed. At the same time, the second resistor R2 and the fourth resistor R4 are set as varistors whose resistance values increase synchronously when stressed, and the increase amplitude ΔR1 is equal to the decrease amplitude ΔR2. The voltage difference Vout is also completely linearly related to the pressure received by the pressure sensor 14.
[0039] In some embodiments, please refer to Figure 5 , for Figure 3 Another connection method of the pressure sensor shown. The first resistor R11 and the second resistor R22 are varistors with equal resistance values. The third resistor R33 and the fourth resistor R44 are fixed-value resistors with equal resistance values. The first resistor R11 is a varistor whose resistance value increases when stressed. The second resistor R22 is a varistor whose resistance value decreases when stressed, and the increase amplitude ΔR1 is equal to the decrease amplitude ΔR2. The voltage difference Vout is completely linearly related to the pressure received by the pressure sensor.
[0040] It can be understood that the first resistor R11 can also be set as a varistor whose resistance value decreases when stressed. At the same time, the second resistor R22 is set as a varistor whose resistance value increases when stressed, and the increase amplitude ΔR1 is equal to the decrease amplitude ΔR2. The voltage difference Vout is also completely linearly related to the pressure received by the pressure sensor.
[0041] In some embodiments, please refer to Figure 6 , for Figure 3 Another connection method of the pressure sensor shown. The second resistor R222 and the fourth resistor R444 are fixed-value resistors with equal resistance values. The first resistor R111 and the third resistor R333 are varistors with equal resistance values, and their resistance values increase or decrease synchronously when stressed. The voltage difference Vout is completely linearly related to the pressure received by the pressure sensor.
[0042] The processing circuit 15 includes a signal amplifier 151 and an encoder 152. The first output terminal Vout1 is connected to the first input terminal of the signal amplifier 151, and the second output terminal Vout2 is connected to the second input terminal of the signal amplifier 151. The encoder 152 is connected to the output terminal of the signal amplifier 151 and is used to encode a digital signal according to the voltage difference Vout between the first output terminal Vout1 and the second output terminal Vout2. Specifically, the voltage value of the voltage difference Vout can be divided according to the pressure sensing level, and the encoder 152 encodes different pressure sensing levels into different digital codes.
[0043] The processing circuit 15 further includes a processor 153 and a transmitting unit 154 which are connected and arranged. The encoder 152 is connected to the processor 153, and the processor 153 controls the transmitting unit 154 to transmit the digital signal to the handwriting sensing device. The transmitting unit may specifically include an LC resonance circuit, and the digital signal is transmitted through electromagnetic waves.
[0044] It can be understood that those skilled in the art can set the signal amplifier 151, the encoder 152 and the processor 153 on different chips or integrate them into the same chip according to actual needs, and specific limitations are not made here. For example, the signal amplifier 151 and the encoder 152 can be built in the processor 153, or only the signal amplifier 151 can be built in the processor 153, or only the encoder 152 can be built in the processor 153, or the signal amplifier 151, the encoder 152 and the processor 153 can be all independently arranged, and so on.
[0045] The processing circuit 15 further includes a power supply unit 155. The power supply unit 155 is connected to the LC resonance circuit. The LC resonance circuit receives the excitation signal sent by the handwriting sensing device and charges the capacitor of the LC resonance circuit. The power supply unit 155 extracts power from the LC resonance circuit to supply power to the pressure sensor 14 and the processing circuit 15, and provides the power supply voltage Vdd.
[0046] In some embodiments, the handwriting input pen can be provided with a battery, which is connected to the power supply unit to supply power to the pressure sensor and the processing circuit.
[0047] Compared with the prior art, the handwriting input pen 10 provided by the present utility model is provided with a pressure sensor 14 to sense the pressure generated by the writing of the pen core 12. The pressure sensor 14 includes a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The first ends of the first resistor R1 and the second resistor R2 are connected to the second output terminal Vout2. The second ends of the second resistor R2 and the third resistor R3 are grounded to GND. The first ends of the third resistor R3 and the fourth resistor R4 are connected to the first output terminal Vout1. The second ends of the fourth resistor R4 and the first resistor R1 are connected to the power supply voltage Vdd. At least one of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 is a varistor. By detecting the change in the voltage difference Vout, the change in the writing pressure can be detected. The voltage difference is calculated according to the resistor voltage division. The specific resistance values of each resistor do not need to be set to specific values, the requirement for the resistor accuracy is low, and good stability can be maintained, and it is not easily interfered by external environmental factors, and the consistency is good. At the same time, it has a high measurement accuracy and can truly restore the writing handwriting, thereby improving the writing experience.
[0048] In addition, the pressure sensor 14 composed of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 has a lower cost compared with a high-precision variable capacitor for detecting pressure.
[0049] The above are only some embodiments of the present utility model, and thus do not limit the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the content of the utility model specification and drawings, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present utility model.
Claims
1. A handwriting input pen, comprising: A pen tip for generating pressure during writing, characterized in that it further comprises; A pressure sensor for sensing the pressure transmitted by the pen tip, including a first resistor, a second resistor, a third resistor, and a fourth resistor. The first ends of the first resistor and the second resistor are connected to a second output terminal, the second ends of the second resistor and the third resistor are grounded, the first ends of the third resistor and the fourth resistor are connected to a first output terminal, and the second ends of the fourth resistor and the first resistor are connected to a power supply voltage. Wherein, at least one of the first resistor, the second resistor, the third resistor, and the fourth resistor is a varistor; A processing circuit connected to the first output terminal and the second output terminal, and the voltage difference between the first output terminal and the second output terminal changes with the change of pressure.
2. The handwriting input pen according to claim 1, characterized in that, The voltage difference between the first output terminal and the second output terminal is linearly related to the pressure received by the pressure sensor.
3. The handwriting input pen according to claim 1, wherein The first resistor, the second resistor, the third resistor, and the fourth resistor are all varistors.
4. The handwriting input pen according to claim 3, wherein The resistance values of the first resistor, the second resistor, the third resistor, and the fourth resistor are equal. Among them, the first resistor and the third resistor are varistors whose resistance values increase synchronously when stressed, the second resistor and the fourth resistor are varistors whose resistance values decrease synchronously when stressed, and the increase amplitude and the decrease amplitude are equal. Or, the first resistor and the third resistor are varistors whose resistance values decrease synchronously when stressed, the second resistor and the fourth resistor are varistors whose resistance values increase synchronously when stressed, and the increase amplitude and the decrease amplitude are equal.
5. The handwriting input pen according to claim 1, wherein The first resistor and the second resistor are varistors with equal resistance values, the third resistor and the fourth resistor are fixed-value resistors with equal resistance values. Among them, the first resistor is a varistor whose resistance value increases when stressed, the second resistor is a varistor whose resistance value decreases when stressed, and the increase amplitude and the decrease amplitude are equal. Or, the first resistor is a varistor whose resistance value decreases when stressed, the second resistor is a varistor whose resistance value increases when stressed, and the increase amplitude and the decrease amplitude are equal.
6. The handwriting input pen according to claim 1, wherein The second resistor and the fourth resistor are fixed-value resistors with equal resistance values, the first resistor and the third resistor are varistors with equal resistance values, and their resistance values increase or decrease synchronously when stressed.
7. The handwriting input pen according to claim 1, wherein The processing circuit includes a signal amplifier. The first output terminal is connected to the first input terminal of the signal amplifier, and the second output terminal is connected to the second input terminal of the signal amplifier.
8. The handwriting input pen according to claim 7, characterized in that, The processing circuit includes an encoder connected to the output terminal of the signal amplifier for encoding the voltage difference signal between the first output terminal and the second output terminal into a digital signal.
9. The handwriting input pen according to claim 8, characterized in that, The processing circuit further includes a processor and a transmitting unit. The encoder is connected to the processor, and the processor is used to control the transmitting unit to transmit the digital signal.
10. A handwriting device, comprising a handwriting input pen and a handwriting sensing device used in cooperation, characterized in that, The handwriting input pen is the handwriting input pen according to any one of claims 1-9.