CN116594517A

CN116594517A - Pressure sensing-clicking fusion sensing system and method for capacitive stylus

Info

Publication number: CN116594517A
Application number: CN202310603859.0A
Authority: CN
Inventors: 周其伟; 吴敏; 王进
Original assignee: Nanjing Pairui Semiconductor Co ltd
Current assignee: Nanjing Pairui Semiconductor Co ltd
Priority date: 2023-05-25
Filing date: 2023-05-25
Publication date: 2023-08-15

Abstract

The invention relates to the technical field of capacitive touch pens, and provides a pressure sensing and clicking fusion sensing system and method for a capacitive touch pen, wherein the fusion sensing method comprises the following steps: based on the comparison of the detected holding capacitance value and a calibrated holding detection threshold value, detecting holding behavior, when the holding behavior is detected, starting nib pressure sensing stress detection and click trigger detection of a pen body, and obtaining nib stress under the corresponding polar plate distance through nib pressure sensing stress detection; and judging that the user has multi-click touch behaviors through click trigger detection, and outputting a response signal. The invention adopts a single-chip implementation scheme, only one multi-channel capacitance measurement chip is needed, and two or more functions are realized at the same time; meanwhile, in the design of the invention, the assembly difficulty of parts is low, the assembly precision and reliability are improved, the space is saved, and the BOM cost is controllable.

Description

Pressure sensing-clicking fusion sensing system and method for capacitive stylus

Technical Field

The invention relates to the technical field of capacitive touch pens, in particular to a pressure sensing-clicking fusion sensing system and method for a capacitive touch pen.

Background

The touch pen is one of the input modes with the most matched capacitive screen and one of the input modes which is most fit with human writing logic. The touch pen product commonly used at present can not sense the pressing force of a user during writing and further output different handwriting if the pressure sensing grading function of the pen point part is not provided, and only the touch and basic writing effect can be achieved.

A few touch pen products with a pressure-sensitive grading function are based on the strain effect of a strain resistor body made of metal or semiconductor, the strain effect is realized by a stress transmission structure arranged in the pen body of the touch pen, the pressure-sensitive strain gauge is pressed to deform in the use process of the touch pen, the change of the resistance value of the pressure-sensitive strain gauge is detected, and then sampling and conversion are carried out through a high-resolution analog-digital converter (ADC), so that the handwriting with the grading of 4096 is output.

The stress transmission structure of the resistance strain type scheme adopted in the prior art is relatively complex in structural design, for example, a pressure sensing assembly and a touch pen disclosed in patent application publication No. CN114201063A are provided with an elastic sheet, a main shaft, a support and a strain type sensor, the main shaft is rigidly connected with a pen point and penetrates through the support to be abutted to the abutting body position of the elastic sheet, the strain type sensor is attached to the attaching body position of the elastic sheet, and the abutting body position is spaced from the attaching body position and connected through an intermediate connector. Therefore, after the nib receives the pressure of the screen, the main shaft can move, so that the supporting body is pushed to move in the direction away from the attaching body, and the attaching body is relatively fixed with the support, the attaching body can deform at the moment, and the output signal of the strain sensor can change along with the different deformation of the attaching body, so that the writing pressure is detected. It should be noted that in nib pressure-sensing designs employing resistive strain mode, one basic premise that piezoresistive strain gauges are used to make stress measurements is that: the presence of an elastomer (such as the attachment of the dome used in CN114201063 a) is also known as encapsulation of piezoresistive strain gauges on rigid structures made of special materials and structures, and thus allowing complete recovery after strain has occurred. In other words, in the nib structure of the stylus, due to the lack of the elastomer, the pressure-sensitive strain gauge scheme is difficult to completely recover in a short time after being stressed or overloaded for a long time (frequently), so that creep, fatigue and even structural damage are very easy to occur, and the measurement stability is poor. Meanwhile, in a narrow touch pen space, the assembly difficulty of assembling 2 groups or 4 groups of miniature piezoresistive strain gauges is high, and the assembly precision can greatly influence the measurement precision of the nib pressure sensing, so that the pressure sensing grading effect is influenced.

Capacitive touch pens are increasingly being used in smart phones, tablet computers, notebook computers, electronic readers, electronic whiteboards and other products to simulate interactions between a human finger and a capacitive touch pen, but most products only have interactions between a pen tip and a capacitive screen, do not have a fast switching function, such as switching from a writing or drawing mode to an eraser, switching from a hand tool to a pen tool and the like, only play basic touch and writing functions, and when function switching is needed, only the touch pen or a writing medium needs to be independently operated to switch, for example, the touch pen needs to be switched by a button on the touch pen, a writing head is switched, the touch pen rotates, and a virtual button is switched by clicking a function switching button on the writing medium screen, so bad experience is brought to writing.

Disclosure of Invention

Aiming at the technical problems and defects of the capacitive stylus in the prior art, the invention aims to provide a pressure sensing-clicking fusion sensing system for realizing the stylus by adopting a single multi-channel capacitive detection chip, so as to realize pressure sensing detection and touch (clicking) triggering detection in the writing process of holding a stylus body by a user, be favorable for realizing control of writing precision and quick switching of functions/modes of the stylus, improve use experience, reduce assembly cost and improve assembly precision and reliability.

According to a first aspect of the object of the present invention, there is provided a pressure-click fusion sensing system for a capacitive stylus having a body portion and a tip portion protruding from a front end of the body portion, the pressure-click fusion sensing system comprising:

a crankshaft arranged along the longitudinal axis direction of the pen body part and provided with a body, a first shaft end and a second shaft end which are positioned at two ends of the body; the first shaft end of the crankshaft is connected with the pen point part and can synchronously move with the pen point part, the second shaft end opposite to the crankshaft is sleeved in a central hole of a first supporting part in a sliding way, and the first supporting part is positioned in the pen body part and positioned at the tail part;

an elastic limit mechanism arranged between the body of the crankshaft and the first supporting part and used for accumulating force when the pen point part is pressed to enable the crankshaft to move towards the first supporting part, so that the crankshaft moves towards an initial position when the pressing is weakened or relieved;

the second supporting part is in a position fixing relation with the pen body part and is positioned in a cavity formed by the body of the crankshaft;

the first polar plate and the second polar plate are arranged in parallel between the second supporting part and an inner wall surface of the cavity to construct a bipolar plate capacitance model;

The third polar plate is stuck to the inner wall surface of the pen body in a cylindrical shape and is positioned in the holding area of the hand of a person, and an open capacitance model is constructed between the third polar plate and the pen body;

the capacitance measuring part is provided with at least two detection channels, wherein the first detection channel is connected with the first polar plate and the second polar plate and is used for detecting capacitance values of the first polar plate and the second polar plate at different polar plate intervals; the second detection channel is connected with the third pole plate and is used for detecting the capacitance value under the action of clicking by fingers when a user holds the pen body;

and the processor system is electrically connected with the capacitance measuring part and is used for obtaining the nib stress of the nib according to the capacitance value obtained by the corresponding detection channel, judging the function switching behavior of a user and controlling the preset function switching of the touch control pen.

As an alternative embodiment, the first and second support portions are configured as part of the pen body portion and remain relatively stationary with respect to the pen body portion.

As an alternative embodiment, the first and second support portions are configured as separate members that are secured to the body portion and that remain relatively stationary with respect to the body portion.

As an alternative embodiment, the cavity formed by the body of the crankshaft is configured as a U-shaped cavity, the surface of which along one of the two inner wall surfaces in the longitudinal axis direction of the pen body is used for mounting the first polar plate or the second polar plate.

As an alternative embodiment, the first electrode plate and the second electrode plate adopt the same structure and are all parallel plate electrodes or are all curved parallel plate electrodes.

As an alternative embodiment, the elastic limit mechanism comprises at least one spring.

As an alternative embodiment, the elastic limiting mechanism is sleeved on the outer circumferential surface of the second shaft end.

As an alternative embodiment, the pen body, the pen tip, the first shaft end of the crankshaft and the second shaft end, the first support, the second support, and the elastic limiting mechanism are arranged concentrically.

As an alternative embodiment, the processor system comprises a nib pressure sensing part configured to obtain the corresponding nib stress based on the capacitance value output by the first detection channel according to the following manner:

σ＝E*d _σ ＝E*(kε ₀ A)/C

wherein σ represents the nib stress, d _σ Representing the plate spacing between the first plate and the second plate in the loaded state; e represents Young's modulus of the elastic limiting mechanism, A represents electrode plate areas of the first electrode plate and the second electrode plate, k represents relative dielectric constant, epsilon ₀ The vacuum dielectric constant is represented, and C represents the capacitance value output by the first detection channel of the capacitance measuring part.

As an optional implementation manner, the processor system includes a multi-click triggering processing part configured to determine whether a sudden change of capacitance exceeding a preset threshold range is detected twice or more within a preset response time according to the capacitance value output by the second detection channel, thereby determining whether the user triggers a function switching operation in a holding state.

According to a second aspect of the present invention, there is also provided a pressure-click fusion sensing method for a capacitive stylus, comprising the steps of:

based on the capacitance value output by the second detection channel and a calibrated holding detection threshold C ₀ Comparing, carrying out holding behavior detection, and when the holding behavior is detected, starting nib pressure sensing force detection and click trigger detection of the pen body:

the nib pressure sensing stress detection includes:

based on the force applied by a user when holding the capacitive stylus to write on the surface of the writing medium, the pen point part retracts towards the inside of the pen body part and synchronously moves the crank shaft;

based on the change of the plate spacing between the first plate and the second plate caused by the motion of the crankshaft, acquiring a capacitance value of a first detection channel of the capacitance measuring part under the condition of detecting and outputting different plate spacing; and

According to the capacitance values under different polar plate intervals detected and output by the first detection channel, the nib stress under the corresponding polar plate intervals is obtained;

the click trigger detection includes:

and in the preset response time, acquiring the current holding capacitance value detected and output by the second detection channel of the capacitance measuring part and the holding capacitance value obtained by the previous measurement to calculate a capacitance difference value, judging whether the capacitance difference values obtained by at least two continuous measurements reach a preset first threshold value, if so, judging that the user has multi-touch behaviors, and outputting a response signal, otherwise, continuously carrying out capacitance detection and judgment.

As an optional implementation manner, the processor system obtains the nib stress under the corresponding polar plate interval according to the capacitance value under the different polar plate intervals detected and output by the first detection channel, and the method includes:

σ＝E*d _σ ＝E*(kε ₀ A)/C

wherein σ represents the nib stress; d, d _σ Representing the plate spacing between the first plate and the second plate in the loaded state; e represents Young's modulus of the elastic limiting mechanism, A represents electrode plate areas of the first electrode plate and the second electrode plate, k represents relative dielectric constant, epsilon ₀ Represents the vacuum dielectric constant, C represents the capacitance measuring sectionCapacitance value of the first detection channel output.

As an alternative embodiment, the capacitance type stylus is calibrated to hold detection threshold C ₀ Is set as follows:

when the capacitive stylus is started for the first time, a capacitance value C before holding is obtained _pre ；

Based on the first holding behavior, a capacitance value C after holding is obtained _afta The method comprises the steps of carrying out a first treatment on the surface of the And

setting a grip detection threshold C ₀ ＝(C _pre +C _afta )/2。

setting a grip detection threshold C ₀ ＝k*(C _pre +C _afta ) And/2, wherein k represents a compensation coefficient, and the initial value of k is 1.

As an alternative embodiment, the method is based on the capacitance value output by the second detection channel and a calibrated holding detection threshold C ₀ Comparing, performing a grip behavior detection, including:

acquiring a calibrated grip detection threshold C ₀ ；

The holding capacitance value output through the second detection channel and the holding detection threshold C ₀ And (3) comparison:

when the holding capacitance value is greater than or equal to the holding detection threshold C ₀ And if not, judging that the holding behavior does not exist.

The pressure sensing-clicking fusion sensing system for the touch pen provided by the invention can be based on a single multichannel capacitance measuring chip, simultaneously measure capacitance values of two channels, realize nib pressure sensing grading and multi-click triggering functions of a pen body on the touch pen, and can be used for stably and reliably operating the touch pen under the condition of controllable cost, such as fast switching input and erasing states and the like by a multi-click triggering mode of a high-precision capacitance measuring principle.

Drawings

Fig. 1 is a schematic structural diagram of a capacitive stylus according to an embodiment of the invention.

Fig. 2 is a front view of the capacitive stylus of the embodiment of fig. 1, wherein the internal structure of the body portion is partially exemplified.

Fig. 3 is a cross-sectional view of the capacitive stylus of the embodiment of fig. 1, showing an example of a pressure-sensitive hierarchical sensing mechanism.

Fig. 4 is a schematic structural diagram of a crank shaft of a capacitive stylus according to an embodiment of the invention.

Fig. 5 is a schematic diagram of a matching structure of a crank shaft and two supporting parts of a capacitive touch pen according to an embodiment of the invention.

Fig. 6 is a schematic diagram of a pressure-sensitive graded sensing device of a capacitive stylus according to an embodiment of the invention.

Fig. 7 is a schematic diagram of a finger-held capacitive stylus according to an embodiment of the invention.

Fig. 8 is a schematic diagram illustrating a position of a third plate in a capacitive stylus according to an embodiment of the invention.

Fig. 9 is a flowchart of a multi-click trigger processing method according to an embodiment of the present invention, in which a double-click trigger is taken as an example.

Fig. 10 is a schematic diagram of a holding state identifying process according to an embodiment of the present invention.

FIG. 11 is a schematic diagram of a pressure-click fusion sensing system in accordance with an embodiment of the present invention.

Fig. 12 is a flowchart of a pressure sensing-click fusion sensing method according to an embodiment of the invention.

The reference numerals have the following meanings:

100-capacitive stylus;

10-a pen body part; 20-pen tip;

30-crank shaft; 31-body; 32-a first axial end; 33-a second axial end; 35-cavity; 36-a guide;

40-a first support;

50-an elastic limiting mechanism;

60-a second support;

101-a first polar plate; 102-a second plate; 103-a third plate;

200-capacitance measuring part;

a 300-processor system; 301-nib pressure sensing measurement part; 302-a multi-click trigger processing section;

400-desktop, 401-readout interface.

Detailed Description

For a better understanding of the technical content of the present invention, specific examples are set forth below, along with the accompanying drawings.

Aspects of the invention are described in this disclosure with reference to the drawings, in which are shown a number of illustrative embodiments. The embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, may be implemented in any of a number of ways, as the disclosed concepts and embodiments are not limited to any implementation. Additionally, some aspects of the disclosure may be used alone or in any suitable combination with other aspects of the disclosure.

The capacitive stylus 100 of the embodiment shown in fig. 1-6 includes a body portion 10, a tip portion 20, and a pressure-sensitive stage sensing device located inside the body portion 10. The pressure-sensitive graded sensing means is used to sense and output the stress generated by the tip 20 based on the force applied by writing during the sliding of the writing medium surface, i.e., the pressure-sensitive output. Thus, a processor disposed within the capacitive stylus 100 and/or writing medium may implement various controls and switches based on the pressure-sensitive output, such as controlling writing of different thicknesses.

As shown in fig. 2, the nib 20 may be provided to be coupled to the inside of the body 10 by a shaft.

As shown in fig. 1 and 2, for convenience of description, two ends of the pen body 10 are defined as a front end 11 (i.e., a head) and a rear end 12 opposite to the front end, respectively. The nib 20 protrudes from the front end 11 of the body 10, for example from the body 10 on an axis basis.

As shown in fig. 2 to 4, a crankshaft 30 is disposed in the longitudinal axis direction of the pen body 10 inside the pen body 10, and the crankshaft 30 has a body 31 and first and second shaft ends 32 and 33 at both ends of the body 31, as shown in fig. 3 and 4.

The first shaft end 32 of the crankshaft 30 is coupled to the nib 20, such as by threads, keyed connections, etc., such that a rigid, fixed connection is formed therebetween.

The second opposite end 33 of the crankshaft 30 is slidably received in a central bore 41 of a first support portion 40. As shown in FIG. 3, the first support portion 40 is positioned within the body portion 10 at a rearward position, and a central bore 41 is disposed in the longitudinal axial direction thereof coaxially with the axis of the body portion 10, the central bore 41 extending toward the rearward end 12 of the body portion 10.

In an alternative embodiment, the first support 40 is configured as part of the pen body 10.

In an alternative embodiment, the first shaft end 32 and the second shaft end 33 have the same cross-sectional shape and dimensions, for example involving an elongate cylindrical shaft, facilitating sliding movement and guiding at both ends. The second axial end 33 has a length that is greater than the length of the first axial end 32 in the direction along the aforementioned longitudinal axis.

In the example shown in connection with fig. 3 and 5, based on the connection of the first shaft end 32 of the crank shaft 30 with the pen tip 20, when the pen tip 20 of the capacitive stylus 100 performs writing sliding on the surface of a writing medium (such as a display screen of a tablet computer device configured with a capacitive screen), the pen tip 20 is subjected to writing pressure to generate movement towards the tail end 12, so that the crank shaft 30 is pushed to synchronously move, and the second shaft end 33 of the crank shaft 30 slides in the central hole 41 towards the tail end 12.

As shown in fig. 3 and 5, an elastic stopper mechanism 50, for example, a coil spring as shown, is disposed between the main body 31 of the crankshaft 30 and the first support portion 40, and is fitted around the outer periphery of the second shaft end 33 of the crankshaft 30, and when the pen tip 20 is pressed to move the crankshaft 30 toward the first support portion 40, the force is accumulated to move the crankshaft 30 toward the initial position when the pressing is weakened or released.

Referring to fig. 3 and 5, as the second shaft end 33 of the crankshaft 30 slides in the direction of the tail portion 12 within the central hole 41, the elastic stopper mechanism 50 (for example, a coil spring) is compressed and accumulated, whereby, when the pressure is released or relieved, the elastic stopper mechanism 50 based on the accumulated force will drive the crankshaft 30 to move toward the front end 11, and return to its original position.

As shown in connection with fig. 3, 4 and 5, the body 31 of the crankshaft 30 is formed with a cavity 35, particularly a U-shaped cavity. In this U-shaped cavity design, a surface of one of two inner wall surfaces thereof along the longitudinal axis direction of the body portion 10 is used for mounting the first plate 101 or the second plate 102. The other plate is mounted on the surface of the second support 60 in the U-shaped cavity and the plates are held in face-to-face distribution.

A second support portion 60 disposed within the U-shaped cavity, wherein the second support portion 60 is configured as part of the pen body portion 10, thereby maintaining a fixed positional relationship with the pen body portion 10. And, a certain gap is left between the sidewall surface of the second supporting portion 60 and the sidewall surface of the cavity 35, so as to facilitate the installation of two capacitor plates.

It is particularly preferable that the surface of the second supporting portion 60 and the surface of the inner wall surface of the cavity 35 are flat surfaces, so that the capacitor plate can be mounted.

In connection with the illustration, the surface of the other of the two inner wall surfaces of the U-shaped cavity is provided with a guide portion 36, whereby the body 31 can move along the guide portion 36.

In the example shown in fig. 3, 5, and 6, the first electrode plate 101 and the second electrode plate 102, which are disposed in pairs, are respectively located on a pair of inner wall surfaces of the second supporting portion 60 opposite to the cavity 35, and in the example shown in fig. 3, the first electrode plate 101 and the second electrode plate 102 are fixed by adhesion, so as to construct a bipolar plate capacitance model.

The first and second electrode plates 101 and 102 are installed in the right-side space between the second support 60 and the cavity 35, respectively.

Based on the relative stationary state (relative position is unchanged) of the second supporting portion 60 and the pen body portion 10, when the pen tip portion 20 is pressed to cause the crankshaft 30 to displace toward the tail portion 14, the plate distance d between the first plate 101 and the second plate 102 is changed, so that the electrostatic capacitance between the first plate 101 and the second plate 102 is changed, such change can be sensed and detected by the capacitance measuring chip, and a corresponding capacitance value is output.

In connection with the illustrated example, when pen tip 20 is displaced under pressure, first shaft end 32 and second shaft end 33 both move in the same direction in synchronization. In the example shown in fig. 3, the second shaft end 33 is displaced in the aforementioned center hole 41, and is guided by the center hole 41 so as to be kept moving in the direction of the center axis of the pen body 10.

In an alternative example, the front end 11 of the body portion 10 is at least partially in nested guiding relationship with the first axial end 32 of the crankshaft 30 such that the first axial end 32 of the crankshaft 30 is guided during movement and is maintained in movement along the central axis of the body portion 10.

In an alternative example, the first and second supporting parts 40, 60 are constructed as separate members fixed to the body part 10 and both are maintained in a relatively stationary state with respect to the body part 10, thereby causing the plate interval d between the first and second plates 101, 102 to be varied based on the variation in interval between the inner wall surface of the cavity of the crankshaft 30 and the second supporting part 60 during the movement of the crankshaft 30 therebetween, so that the electrostatic capacity between the first and second plates 101, 102 is varied.

Of course, in other embodiments, the relationship between the first support 40, the second support 60 and the crankshaft 30 may be configured in other suitable manners, so that one of the capacitor plates (for example, the first plate 101) can be rigidly connected to the pen tip 20 and synchronously move, and can be limited by a spring to avoid overload; meanwhile, the other capacitor plate (for example, the second plate 102) is rigidly connected with the housing of the pen body 10 or is a part of the housing, and is always in a relatively static state with the pen body 10.

In some examples, the first support 40, the second support 60 are each block members perpendicular to the longitudinal axis of the barrel 10.

In the example shown in fig. 6, the capacitance measuring unit 200 may employ a multi-channel capacitance detection chip, such as a high-precision capacitance sensor measurement chip PMDS-F4 of the semiconductor limited company of tokyo surge. The first detection channels of the capacitance measuring unit 200 are respectively connected to the first electrode plate 101 and the second electrode plate 102, and are used for detecting capacitance changes of the first electrode plate 101 and the second electrode plate 102 under different plate pitches, and outputting capacitance values.

Therefore, the pressure-sensing graded sensing mechanism composed of the crankshaft 30, the first supporting portion 40, the elastic limiting mechanism 50 (taking a coil spring as an example), the second supporting portion 60, the first polar plate 101 and the second polar plate 102 according to the foregoing embodiment of the present invention can realize sensing of the stress load of the pen tip based on the change of the polar plate distance between the first polar plate 101 and the second polar plate 102, and realize capacitive pressure-sensing graded sensing output of the stylus with reliable structure and accurate measurement.

As a preferred example, the pen body 10, the pen tip 20, the first shaft end 32 of the crankshaft 30, the second shaft end 33, the first support 40, the second support 60, and the elastic stopper mechanism 50 are arranged concentrically.

Referring to fig. 3 and 6, the pressure-sensitive graded sensing mechanism according to the embodiment of the present invention is configured such that the plate pitches in the idle, loaded, full and overload states are as follows:

no load: d=d ₀ ，d ₀ Represents the plate spacing under no load, d ₀ ＝0；

And (3) carrying: d=d _σ ，d _σ Represents the plate spacing under load, d _σ σ/E, wherein σ is the nib stress, E is the young's modulus of the elastic limit mechanism, and is a constant;

full load: d=d, where D is the maximum compression of the elastic limit mechanism, i.e. the number of diameter turns, is a constant;

overload: because the spring limiting mechanism exists, overload cannot be generated, and therefore destructive influence on the capacitive pressure sensing hierarchical structure cannot be generated, and the spring limiting mechanism plays a role in protection.

Thus, in embodiments of the present invention, the coil spring is in a relatively free state in the unloaded state, with the two capacitive plates (i.e., the first plate 101 and the second plate 102) in close proximity, and the electrostatic capacitance output C is near infinity. Because the touch pen is more in a non-input state in the life cycle, the pressure-sensitive hierarchical sensing mechanism can better protect the measuring structure.

Meanwhile, in the loaded state, the coil spring is continuously compressed, the first polar plate 101 and the second polar plate 102 are separated and gradually pulled away, the electrostatic capacity output C is continuously reduced, and the high-reliability and high-stability linear relation with the compression ratio of the coil spring is maintained, so that the nib pressure feeling can be graded in a high resolution way, such as 4096 or higher.

Further, when the capacitive stylus 100 provided by the invention falls carelessly, the pressure sensing device is not damaged by the instant impact of the first polar plate 101 and the second polar plate 102 due to the dual limit protection of the elastic limit mechanism 50 and the second support portion 60, so that the falling resistance and reliability of the capacitive stylus are greatly improved.

As described above, in the embodiment of the present invention, the distance between the first polar plate 101 and the second polar plate 102 increases with the increase of the detected pressure at the nib, as shown in the drawing, the second polar plate 102 is fixed on the side wall of the cavity 35 formed by the body 31 of the crankshaft 30, and with the increase of the pressure at the nib, the distance between the second polar plate 101 and the first polar plate 101 fixed to the second supporting part 60 (for example, formed as a part of the pen body) is continuously increased, so as to realize the capacitance output detection and the pressure detection, and meanwhile, with the design of the pressure-sensing graded sensing device and the measuring method according to the present invention shown in fig. 2 and 3, due to the existence of the elastic limiting mechanism 50 (such as a coil spring) located between the crankshaft 30 and the first supporting part 40, the limitation and the limiting action of the maximum deformation amount of the elastic limiting mechanism 50 will not generate an overload condition, so that the capacitive pressure-sensing graded structure will not be destructively affected, and simultaneously, the elastic limiting mechanism and the second supporting part 60 are combined to play a double-layer protection role, and the capacitive pressure-sensing graded sensing device will not be damaged due to the sudden drop or the impact of the pressure-sensing device caused by other reasons, and the reliability of the pen point may not be improved.

It should be appreciated that the aforementioned resilient limiting mechanism 50 for overload protection may also be designed in other suitable ways, and is not limited to coil springs, e.g. wave springs, etc. may also be used.

In the embodiment of the present invention, the capacitance measuring unit 200 is configured, for example, as a high-resolution capacitance measuring chip, which is electrically connected to the pen tip pressure sensing unit 300 disposed in the pen body 10, and the corresponding pen tip stress is obtained based on the value of the capacitance outputted from the capacitance measuring unit 200.

As shown in fig. 7 and 8, a third electrode plate 103, for example, a thin plate electrode, is disposed in the pen body 10, and is attached to the inner wall surface of the pen body 10 in a cylindrical shape, and an open capacitance model is formed between the pen body and the hand holding area.

As a result, as shown in fig. 7 and 8, the second detection channel of the capacitance measuring unit 200 is connected to the third electrode plate 103, and the capacitance value of the hand 1000 in the finger clicking operation when holding the pen body 10 can be detected and output.

As shown in fig. 6, a processor system 300 is further disposed in the pen body 10, for example, a processing chip integrated on a PCB, especially a low-power-consumption embedded processing chip is used to control the whole stylus, especially in the embodiment of the invention, the processor system 300 is configured to obtain the stress of the pen tip according to the capacitance value obtained by the corresponding detection channel, determine the function switching behavior of the user, and control the preset function switching of the stylus.

The processor system 300 optionally has a nib pressure sensing measurement 301 and a multi-click trigger processing 302.

Wherein the nib pressure sensing measurement portion 301 is configured to obtain the corresponding nib stress based on the capacitance value output by the first detection channel according to the following manner:

σ＝E*d _σ ＝E*(kε ₀ A)/C

wherein σ represents the nib stress, d _σ Representing the plate spacing between the first plate 101 and the second plate 102 in the loaded state; e represents Young's modulus of the elastic limit mechanism 50, A represents plate areas of the first plate 101 and the second plate 102, k represents relative dielectric constant ε ₀ The vacuum dielectric constant is represented, and C represents the capacitance value output from the first detection channel of the capacitance measuring unit 200).

The multi-click trigger processing part 302 is configured to root the capacitance value output by the second detection channel, and determine whether the capacitance abrupt change exceeding the preset threshold range is detected twice or more within the preset response time, thereby determining whether the user triggers the function switching operation in the holding state.

As an alternative example, the multi-click trigger processing section 302 is configured to determine whether the user triggers a function switching operation in the held state in the following manner:

acquiring a calibrated holding detection threshold C of a capacitive stylus ₀ ；

In the using process of the capacitive touch pen, a holding capacitance value output C under the holding state output by the second detection channel is obtained _{meas_n} ；

In response to C _meas Reaching the holding detection threshold C ₀ Entering a multi-click touch behavior detection mode of a user, otherwise, continuously acquiring a holding capacitance value and outputting C _{meas_n} Continuously judging whether to enter a detection mode;

in the multi-touch behavior detection mode of the user, in a preset response time, calculating a capacitance difference value based on a holding capacitance value obtained by current measurement and a holding capacitance value obtained by previous measurement, and when the capacitance difference values obtained by at least two continuous measurements reach a preset first threshold value, judging that the multi-touch behavior exists for the user, and outputting a response signal.

In this regard, we will make more specific description in the following examples.

7-10, multi-tap trigger detection, for capacitive stylus grip and switch behavior detection, is based on an open capacitance model implementation of a single capacitive pad, which is a typical open capacitance model, according to embodiments of the invention. As shown in connection with fig. 7 and 8, the essence of double-click or multi-click) triggering is that the whole hand of a user generates space conductive characteristics on a measuring polar plate single polar plate attached inside the pen body when the user holds the pen, and the space conductive characteristics are further reflected by the detection output of the capacitance value. The capacitance model is a single capacitance polar plate model, and the dielectric constant of the hand of a user is close to 80) of water and the dielectric constant of air is close to 1) jointly act on the capacitance polar plate.

In the example shown in fig. 7, reference numeral 1000 denotes a user's finger, holding the body 10 of the capacitive stylus. The broken line portion indicates the third electrode plate 103 disposed inside the capacitive stylus 100, and is in the shape of a thin sheet.

Because the dielectric constant of the human body is far greater than that of air, the contact area of the hand skin and the pen body is a main interference factor affecting the capacitance output, and meanwhile, the interference of the dynamic change of the pen holding posture of the user on the capacitance measurement is considered, in the embodiment of the invention, the capacitance output is carried out by knocking or touching the position of the polar plate by the finger twice or more, and the capacitance output continuously exceeds the set threshold C within a period of time based on a fluctuating reference capacitance curve _thres Number of acts N of (2) _k Therefore, more stable and reliable user behavior recognition is realized according to the switching action for recognition.

In an embodiment of the invention, the setting is continuously beyond the set threshold C _thres Number of acts N of (2) _k It may be 2 (double click) or 3 (triple click), i.e. the user is considered to have entered a shortcut switching behavior.

It should be understood that, because the spatial electric field output model of the open capacitor plate is affected by the user's holding behavior and the spatial electric field such as the mobile phone call, etc.), in the embodiment of the present invention, in order to further eliminate the interference, improve the robustness of the system, or in order to implement more rapid switching functions, the multi-click triggering is performed more than twice, i.e., N _k 3 or more, and in some embodiments may be configured and implemented in accordance with the present invention.

In connection with the design of the capacitive stylus 100 shown in fig. 8, the pen body 10 and the third pad 103, the capacitance measuring section 200, the processor system 300, and the communication module 500 disposed inside the pen body are schematically shown.

The third electrode plate 103 is in a sheet shape, is cylindrically adhered to the inner wall surface of the body 10 of the capacitive stylus, and is located in a holding area of a human hand.

The capacitance measuring unit 200 is used for detecting the capacitance value output of a capacitance model formed between the body 10 and the third electrode plate 103 of the capacitive stylus when the capacitive stylus is held by a human hand. As an alternative example, the capacitor measuring chip in the prior art may be used for design, and in the example of the present invention, the high-precision capacitor sensor measuring chip PMDS-F4 of the semiconductor limited company of tokyo is taken as an example.

The second detection channel of the capacitance measurement unit 200 is connected to the third electrode plate 103, and is used for detecting and outputting a capacitance value generated by a finger clicking action when the user's hand 1000 holds the pen body 10.

The processor system 300 is connected to the capacitance measuring unit 200 and the communication module 500, respectively.

As described above, the processor system 300 may be implemented using a low power consumption processing chip, which is capable of judging a user's shortcut switching behavior and controlling a switching of a mode or function of the capacitive stylus, for example, a switching from a writing or drawing mode to an eraser, a switching from a hand tool to a pen tool, or the like, according to a capacitance value output from the second channel of the capacitance measuring section 200. It should be appreciated that the programs and instructions executed by such switching operations may be implemented in accordance with the instruction sets and program components of the prior art.

The communication module 500 is used for implementing data communication and interaction between the capacitive stylus 100 and an external device, such as a desktop computer, a laptop computer, a handheld computer, and a mobile intelligent processing device. In fig. 2, a desktop computer 400 is illustrated, wherein reference numeral 401 denotes a read interface.

In the embodiment of the present invention, the communication module 500 is illustrated using a bluetooth module as an example.

It should be appreciated that desktop and laptop computers are typically configured with a display screen and are electrically connected to the capacitive stylus 100 and/or writing medium to enable the display of written content, points of pen and/or writing tracks.

It should be appreciated that the illustrations and the foregoing embodiments are intended to be exemplary descriptions of capacitive stylus designs, with the following components/modules also optionally included within the capacitive stylus: the capacitive touch pen comprises a memory for storing data and program instructions, a wire for realizing electrical connection, a battery module and/or a charge-discharge module for realizing power supply, a PCB (printed circuit board) integrated with one or more functional circuits/chips, and a display module for realizing information characterization, wherein the display module comprises a small display screen, an LED lamp group and the like, and can be designed and realized according to specific functions and requirements of the capacitive touch pen.

7-9, the implementation of the multi-click trigger processing method for a capacitive stylus according to an embodiment of the invention includes the following steps:

During the use of the capacitive stylus, the holding capacitance value output C in the holding state is detected _{meas_n} ；

In response to C _meas Reaching the holding detection threshold C ₀ Entering a multi-click touch behavior detection mode of a user, otherwise, continuously acquiring a holding capacitance value and outputting C _{meas_n} Continuously judging whether to enter a detection mode or not until a preset condition is reached;

In the multi-touch behavior detection mode of the user, in a preset response time, calculating a capacitance difference value based on a holding capacitance value obtained by current measurement and a holding capacitance value obtained by previous measurement, judging that the user has multi-touch behaviors when the capacitance difference values obtained by at least two continuous measurements reach a preset first threshold, and outputting a response signal.

It should be understood that the foregoing predetermined conditions refer to a shutdown operation, a disconnection operation, a low power operation, etc. of the stylus pen, which may be set in advance by a user or preconfigured by the factory of the stylus pen.

In connection with the examples shown in fig. 9 and 10, in order to further eliminate the probability of false triggering, in the embodiment of the present invention, after the user holds the capacitive stylus, first, valid holding state detection is required, and only when the current operation of the capacitive stylus is recognized as a real and valid holding behavior, double-click or multi-stage triggering detection is entered.

For this reason, we generally choose to complete initialization and setting of the holding threshold value during the production process or the factory inspection of the capacitive stylus, that is, to hold the stylus for the first time, to measure and read out the capacitance values before and after holding, and to preset the holding detection threshold value accordingly.

In the embodiment of the invention, after judging that the multi-touch action exists and outputting a response signal, resetting the capacitance tolerance value and the time count each time, reentering the multi-touch action detection mode of the user, and starting the capacitance detection of the holding state and the identification of the user switching action.

As an optional implementation manner, the calibration of the holding detection of the capacitive stylus marks the holding detection threshold C of the capacitive stylus ₀ Comprising the following steps:

setting a grip detection threshold C ₀ ＝(C _pre +C _afta )/2。

Thereby, the grip detection threshold C is set in advance ₀ Can be configured in the memory of the capacitive stylus, and when the capacitive stylus is subsequently used and the gripping behavior is identified, the processor system invokes the judgment and corresponding processing.

It should be appreciated that during subsequent use of the capacitive stylus, if the capacitance value of the measurement output is less than the configured grip detection threshold C ₀ It is assumed that there is no effective gripping action and no double-click or multi-click trigger recognition process, i.e. measurement state, has to be entered. Only when the capacitance value of the measured output is greater than or equal to the configured holding detection threshold C ₀ Then the subsequent double-click or multi-click trigger identification process is performed.

As another embodiment, the holding detection of the capacitive stylus is calibrated, and the holding detection threshold C of the capacitive stylus is calibrated ₀ Comprising the following steps:

In this embodiment, since the capacitive stylus has an influence on abrasion, erosion, etc. of the surface of the stylus body in the subsequent use process, or the internal electrode plate has an influence on air erosion, oxidization, etc., the adjustable compensation coefficient k is configured to compensate for the problem of variation of the calibration value caused by use.

As an alternative embodiment, the compensation factor k can be set to pass testing, maintenance or be adjusted by a preset configuration program.

As an alternative example, for a capacitive stylus that is normally used beyond a preset time limit range, the compensation coefficient k in terms of the unused time period is preset, and the modification is done automatically inside the capacitive stylus without being perceived by the user. For example, since the user first uses the capacitive stylus, such as to first measure the capacitance value), a time count is made, and after a preset period of time has elapsed, such as 1 year, 1.5 years, 2 years, etc.), the compensation coefficient k is automatically updated in a predetermined manner.

As an optional real mode, in a preset time period, calculating a capacitance value based on a holding capacitance value obtained by current measurement and a holding capacitance value obtained by previous measurement, and determining that a multi-touch action exists for a user when the capacitance values obtained by at least two continuous measurements reach a preset first threshold, including:

continuously acquiring a holding capacitance value output C in a holding state of a user _{meas_n+i} The method comprises the steps of carrying out a first treatment on the surface of the Wherein i represents a capacitance value sampling measurement sequence, counting from 1;

a differential value DeltaC outputted when the holding capacitance value starts at any jth time _n+j Reaching the preset first threshold C _thres J is less than or equal to i, starting time counting, and continuously obtaining the difference value delta C output by the j+1st holding capacitance value _n+j+1 ：

Differential value ΔC output in response to j+1th-hand-hold capacitance value _n+j+1 Reaching a preset first threshold C _thres Further determining the time difference DeltaT from the jth to the (j+1) th actions when DeltaT is at the preset response time T _thres And when the touch screen is in the range, judging that the user has multi-click touch behaviors and outputting a response signal.

Wherein the differential value ΔC is outputted in response to the j+1th-hand-held capacitance value _n+j+1 Not reaching the preset first threshold C _thres And returning to continuously acquire the holding capacitance value output under the holding state of the user.

Wherein in response to the time difference DeltaT exceeding a preset response time T _thres And when the range is reached, returning to continuously acquire the holding capacitance value output under the holding state of the user.

In the embodiment of the invention, the difference value delta C of the holding capacitance value output from any jth beginning _n+j The calculation method adopts the difference between the capacitance value obtained by the current jth measurement and the capacitance value obtained by the last measurement, i.e. the jth-1), and obtains the capacitance value difference, i.e. C _{meas_n+j} -C _{meas_n+j-1} .

When j=i=1, the differential value Δc _n+1 ＝C _{meas_n+1} -C _{meas_n} Representing the capacitance value obtained by the first detection in the measurement mode and the capacitance value C measured last time _{meas_n} Is a difference in (c).

When delta C _n+1 Meet the requirement of being greater than or equal to a preset first threshold C _thres Further obtaining the measurement result of the 2 nd capacitance value when the threshold condition is met,and further calculate ΔC _n+2 ＝C _{meas_n+2} -C _{meas_n+1} Further judge DeltaC _n+2 Whether or not the first threshold C is greater than or equal to a preset first threshold C _thres When the two threshold conditions are satisfied, determining whether the time count range of the two detection actions is within a preset response time T _thres Within the range, if within the preset response time T _thres And if the range is within the range, judging that the user double-click triggering action is performed, identifying the double-click action, outputting a response signal and triggering the switching function.

Thus, according to the time of the response T in a preset state _thres Within the range, whether the capacitance difference value of the two continuous measurement capacitances exceeds a threshold preset first threshold C _thres ) By the double click or the above judgment, it is judged that the double click behavior is recognized and the switching function is triggered based on the double click behavior.

In the embodiment of the invention, in order to eliminate capacitance drift generated by the dynamic state of holding the pen by a user, a differential value is introduced as a reference in the finger trigger judgment, so that the dynamic disturbance of holding the pen by the hand by the user is eliminated, and the measuring and identifying progress and accuracy are improved.

In other embodiments, the response time T is set at a predetermined value _thres And in the range, based on the capacitance difference value, and the capacitance difference values obtained in at least three continuous measurements reach a preset first threshold value, determining that the user has multi-touch behaviors.

Thus, by the judgment of three or more strokes, it is judged that the double-stroke behavior is recognized and the switching function is triggered.

In an alternative embodiment of the present invention, as shown in connection with fig. 12, in order to reduce power consumption, i.e., nib pressure sensing force detection and finger click trigger detection are not continuously performed, but are performed while the capacitive stylus is effectively held, thereby reducing power consumption. For example, subsequent finger click trigger detection and nib pressure sensing force detection may be initiated based on the detection of the gripping behavior.

1, 2, 7, 8 and 11, a schematic diagram illustrating a principle of fusion detection of nib pressure sensing force detection and finger click trigger detection in the whole capacitive stylus is shown, so that the capacitive stylus adopts a single-chip implementation scheme, only one multi-channel capacitance measurement chip is needed, and two or more functions are realized simultaneously; meanwhile, in the design of the invention, the assembly difficulty of parts is low, the assembly precision and reliability are improved, the space is saved, and the BOM cost is controllable.

The pressure-sensitive grading sensing device of the capacitive stylus provided by the invention has the advantages of simple and reliable structural design, easy realization of assembly space and process, high precision, no overload damage and improvement of the pressure-sensitive grading effect. Meanwhile, compared with the scheme that the design of 2 or 4 groups of piezoresistive strain gauges is converted through a high-resolution analog-digital converter ADC, the invention can realize measurement by using a single capacitance measurement chip and simple calculation, and has low cost and better assembly precision.

It should be appreciated that the illustrations and the foregoing embodiments are intended to be exemplary descriptions of the design of a capacitive stylus pressure-sensing hierarchical sensing device and its implementation principles, with the following components/modules also optionally included within the capacitive stylus 100: the wires for implementing electrical connection, the battery module and/or the charge-discharge module for implementing power supply, the PCB board integrating one or more functional circuits/chips, the communication module for implementing communication between the capacitive stylus 100 and an external device, and the display module for implementing information characterization include, but are not limited to, a small display screen, an LED lamp set, etc.).

While the invention has been described with reference to preferred embodiments, it is not intended to be limiting. Those skilled in the art will appreciate that various modifications and adaptations can be made without departing from the spirit and scope of the present invention. Accordingly, the scope of the invention is defined by the appended claims.

Claims

1. A pressure-click fusion sensing system for a capacitive stylus having a body portion (10) and a nib portion (20) extending from a front end of the body portion (10), the pressure-click fusion sensing system comprising:

a crankshaft (30) arranged along the longitudinal axis direction of the pen body (10) and having a body (31), a first shaft end (32) and a second shaft end (33) at both ends of the body (31); the first shaft end (32) of the crankshaft (30) is connected with the pen tip (20) and can synchronously move with the pen tip (20), the second shaft end (33) opposite to the crankshaft (30) is slidably sleeved in a central hole (41) of a first supporting part (40), and the first supporting part (40) is positioned in the pen body (10) and positioned at the tail part;

an elastic limit mechanism (50) arranged between the body (31) of the crankshaft (30) and the first support part (40) and configured to store a force when the pen tip part (20) is pressed to move the crankshaft (30) toward the first support part (40) so as to move the crankshaft (30) toward an initial position when the pressing is weakened or released;

A second support portion (60) in fixed positional relationship with the pen body portion (10) and located within a cavity (35) formed by a body (31) of the crankshaft (30);

the first polar plate (101) and the second polar plate (102) are arranged in parallel between the second supporting part (60) and an inner wall surface of the cavity (35) to construct a bipolar plate capacitance model;

a third pole plate (103) which is stuck on the inner wall surface of the pen body part (10) in a cylindrical shape and is positioned in a holding area of a human hand, and an open capacitance model is constructed between the third pole plate and the pen body part (10);

a capacitance measuring part (200) having at least two detection channels, wherein a first detection channel is connected with the first polar plate (101) and the second polar plate (102) and is used for detecting capacitance values of the first polar plate (101) and the second polar plate (102) at different polar plate distances; the second detection channel is connected with the third polar plate (103) and is used for detecting the capacitance value under the action of clicking by fingers when the pen body 10 is held by the pen body part (10);

and the processor system (300) is electrically connected with the capacitance measuring part (200) and is used for obtaining the nib stress of the nib (20) according to the capacitance value obtained by the corresponding detection channel, judging the function switching behavior of a user and controlling the preset function switching of the touch control pen.

2. The pressure-click fusion sensing system for capacitive stylus according to claim 1, wherein the processor system (300) comprises a tip pressure sensing measurement (301) arranged to obtain the corresponding tip stress based on the capacitance value output by the first detection channel according to:

σ＝E*d _σ ＝E*(kε ₀ A)/C

wherein σ represents the nib stress, d _σ Representing the plate spacing between the first plate (101) and the second plate (102) in the loaded state; e represents Young's modulus of the elastic limit mechanism (50), A represents plate areas of the first plate (101) and the second plate (102), k represents relative dielectric constant, ε ₀ The vacuum dielectric constant is represented, and C represents the capacitance value output by the first detection channel of the capacitance measuring unit (200).

3. The pressure-click fusion sensing system for capacitive styli of claim 1, wherein the first support portion (40), second support portion (60) are configured as part of the body portion (10) and remain relatively stationary with respect to the body portion (10).

4. The pressure-click fusion sensing system for capacitive styli of claim 1, wherein the first support (40), second support (60) are configured as separate members that are fixed to the body (10) and both remain relatively stationary with respect to the body (10).

5. The pressure-click fusion sensing system for a capacitive stylus according to claim 1, wherein the cavity (35) formed by the body (31) of the crankshaft (30) is configured as a U-shaped cavity, a surface of which along one of two inner wall surfaces in a longitudinal axis direction of the stylus body (10) is used for mounting the first plate (101) or the second plate (102).

6. The pressure-click fusion sensing system for a capacitive stylus of claim 5, wherein the first plate (101) and the second plate (102) are of the same construction and are both parallel plate electrodes or are both curved parallel plate electrodes.

7. The pressure-click fusion sensing system for a capacitive stylus of claim 1, wherein the resilient limiting mechanism (50) comprises at least one spring.

8. The pressure-click fusion sensing system for a capacitive stylus of claim 7, wherein the elastic limit mechanism (50) is sleeved on the outer peripheral surface of the second shaft end (33).

9. The pressure-click fusion sensing system for capacitive touch pens according to claim 1, characterized in that the first shaft end (32) of the pen body (10), the pen tip (20), the crankshaft (30) is arranged concentrically with the second shaft end (33), the first support (40), the second support (60), the elastic limit mechanism (50).

10. The pressure-click fusion sensing system for a capacitive stylus according to any one of claims 1-10, wherein the processor system (300) comprises a multi-click trigger processing portion (302) configured to determine whether a sudden change in capacitance exceeding a preset threshold range is detected twice or more within a preset response time according to a capacitance value output by the second detection channel, thereby determining whether a user triggers a function switching operation in a holding state.

11. The pressure-click fusion sensing system for a capacitive stylus according to claim 10, wherein the multi-click trigger processing section (302) is configured to determine whether a function switching operation is triggered by a user in a held state in the following manner:

acquiring a calibrated holding detection threshold value of a capacitive stylusC ₀ ；

12. A pressure-click fusion sensing method for a capacitive stylus based on the pressure-click fusion sensing system for a capacitive stylus of claim 1, comprising the steps of:

the nib pressure sensing stress detection includes:

based on the force applied by a user when holding the capacitive stylus to write on the surface of the writing medium, the pen tip (20) retracts towards the inside of the pen body (10) and synchronously moves the crank shaft (30);

based on the change of the plate spacing between the first plate (101) and the second plate (102) caused by the movement of the crankshaft (30), acquiring a capacitance value of a first detection channel of the capacitance measuring part (200) under the condition of detecting and outputting different plate spacing; and

the click trigger detection includes:

and in the preset response time, acquiring the currently held capacitance value detected and output by the second detection channel of the capacitance measuring part (200) and the held capacitance value obtained by the previous measurement, calculating a capacitance tolerance value, judging whether the capacitance difference values obtained by at least two continuous measurements reach a preset first threshold value, if so, judging that the user has multi-touch behaviors, and outputting a response signal, otherwise, continuously carrying out capacitance detection and judgment.

13. The method for pressure sensing-click fusion sensing of capacitive stylus according to claim 12, wherein the obtaining the nib stress at the corresponding plate pitch according to the capacitance values at the different plate pitches of the detection output of the first detection channel includes:

the processor system (300) is arranged to obtain the pen tip stress as follows:

σ＝E*d _σ ＝E*(kε ₀ A)/C

14. The method of claim 12, wherein the capacitive stylus is calibrated to hold detection threshold C ₀ Is preconfigured as follows:

setting a grip detection threshold C ₀ ＝(C _pre +C _afta )/2。

15. The method of claim 12, wherein the capacitive stylus is calibrated to hold detection threshold C ₀ Is preconfigured as follows:

16. The method of claim 12, wherein the capacitance value output by the second detection channel is based on a calibrated grip detection threshold C ₀ Comparing, the step of carrying out the holding behavior detection specifically comprises the following steps:

acquiring a calibrated grip detection threshold C ₀ ；