WO2017008420A1

WO2017008420A1 - Touch pressure detection device and method

Info

Publication number: WO2017008420A1
Application number: PCT/CN2015/094640
Authority: WO
Inventors: 杨旺旺; 邓耿淳; 皮波
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2015-07-10
Filing date: 2015-11-16
Publication date: 2017-01-19
Also published as: CN105094461A; CN105094461B

Abstract

Disclosed in the present invention are a touch pressure detection device and method. The device comprises a light emitter and a light detector, wherein the light emitter is configured to emit lights to a body part performing a touch action, and the light detector is configured to receive lights reflected back from the body part and acquire a touch pressure generated by the body part according to an intensity of the reflected lights. By emitting lights to the body part performing the touch action, receiving the lights reflected by the blood in the body part, and acquiring the touch pressure generated by the body part according to the intensity of the reflected light, the present invention realizes an optical detection of the touch pressure using the volume of the blood. Compared to the capacitive detection method and the pressure-sensitive resistive detection method in the prior art, the present invention is advantageous in high detection sensitivity, simple structure, compact volume, and low cost.

Description

Touch pressure detecting device and method

Technical field

The present invention relates to the field of pressure detection technology, and in particular, to a touch pressure detecting method and apparatus.

Background technique

In daily life, people use a mobile terminal, and usually use a finger to touch the touch panel to perform operations, such as using a finger to perform fingerprint unlocking, and pressing, clicking, double-clicking, and the like. In many application scenarios, if the touch pressure of the finger can be detected, the operation function of the terminal can be enriched according to the touch pressure, and the user experience can be improved by some system processing. For example, when the user views the map with the mobile terminal, the user can use the finger touch pressure to zoom in or out; for example, the touch pressure can be used to define a new button mode (such as using heavy pressure instead of clicking, Double click, etc., to develop new game features (such as for car acceleration, high jump and squat, etc.), using pressure detection results to control the motor for tactile feedback.

There are two methods for detecting finger touch pressure, one is capacitance detection and the other is varistor detection.

Among them, the capacitance detection method, that is, when the panel with the sensor is pressed by the finger, the greater the finger strength, the larger the area of the finger contact panel, and the larger the capacitance between the detection electrodes below the panel, the finger pressure is determined according to the capacitance. size. This detection method has the following drawbacks:

1) Large volume: the area or distribution area of the detection electrode should be at least equal to the area of the finger, otherwise it is difficult to detect;

2) Poor sensitivity: The contact area of the finger is not very large with the pressure, the amount of change of the capacitance is also small, and the detection sensitivity is limited.

3) Large dispersion: individual finger size itself is different, resulting in different users, the same pressing force, but the detection results vary greatly.

The varistor detection method is to install a varistor pressure sensor under the target detection panel. When the panel is pressed, the panel will have a slight stroke with the pressing force, and the resistance of the varistor mounted under it changes. , thereby quantifying the pressing force according to the magnitude of the resistance change. Such a test The law has the following problems:

(1) Difficulties in achieving the structure: The aforementioned sensor requires a small stroke to detect the pressure change, and it needs to be installed very flat under the panel, making the structure realization method very difficult.

(2) It is easy to be affected by the way the device is placed: If the pressure detecting device is installed on the mobile terminal, when the angle of the center line of the mobile terminal relative to the center of gravity changes, the measurement error will be caused due to the gravity of the panel.

(3) High cost: The cost and structural cost of the sensor will lead to higher cost of the final solution.

In summary, the technical solution for detecting touch pressure in the prior art has the disadvantages of complicated structure, large volume, high realization cost, and low detection sensitivity.

Summary of the invention

The main object of the present invention is to provide a touch pressure detecting device and method, which aims to provide a touch pressure detecting scheme with simple structure, small volume, low cost and high detection sensitivity.

To achieve the above object, the present invention provides a touch pressure detecting device comprising a light emitter and a light detector, wherein:

The light emitter is configured to emit light and illuminate a body part having a touch action;

The photodetector is configured to receive reflected light reflected by the body part, and acquire a touch pressure generated by the body part according to the intensity of the reflected light.

The invention also proposes a touch pressure detecting method, which comprises the following steps:

Emitting light to a body part that has a touch action;

Receiving reflected light reflected from blood in the body part;

Obtaining a touch pressure generated by the body part according to the intensity of the reflected light;

Wherein, the touch pressure is inversely related to the blood volume in the body part, and is positively correlated with the intensity of the reflected light.

The touch pressure detecting device provided by the invention obtains the touch pressure generated by the body part by emitting light to the body part with the touch action and receiving the reflected light reflected by the blood in the body part, and realizing the touch pressure generated by the body part according to the intensity of the reflected light. The optical pressure is detected optically. Compared with the traditional capacitance detection method and varistor detection method, this method has the advantages of high detection sensitivity, simple structure, small volume and low cost.

DRAWINGS

1 is a schematic diagram of a touch pressure detecting device applied to a mobile terminal according to an embodiment of the present invention;

2 is a schematic structural view of an embodiment of a touch pressure detecting device of the present invention;

3 is a schematic block diagram of a light emitter of a touch pressure detecting device according to an embodiment of the present invention;

4 is a schematic block diagram of a photodetector of a touch pressure detecting device according to an embodiment of the present invention;

FIG. 5 is a schematic diagram showing the connection of each unit module of the touch pressure detecting apparatus according to the embodiment of the present invention; FIG.

6 is a schematic diagram of input signals and output signals of the pre-processing module of FIG. 5;

7 is a schematic circuit diagram of a light emitter of a touch pressure detecting device according to an embodiment of the present invention;

8 is a schematic circuit diagram of a photodetector of a touch pressure detecting device according to an embodiment of the present invention;

9A is a schematic view showing the relationship between blood volume and touch pressure in an embodiment of the present invention;

9B is a schematic diagram showing the relationship between electrical signal strength and blood volume in an embodiment of the present invention;

9C is a schematic diagram showing the relationship between the electrical signal strength and the touch pressure in the embodiment of the present invention;

10 is a flow chart of an embodiment of a touch pressure detecting method of the present invention;

Figure 11 is a flow chart of step S13 of Figure 10.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 1, a schematic diagram of a touch pressure detecting device 120 of the present invention applied to a button area 130 of a mobile terminal is shown.

2 is a preferred embodiment of the touch pressure detecting device of the present invention, the device 120 including a cover plate 128, a bottom plate 125, a light emitter 122 and a light detector 124, the light emitter 122 and the light detector 124 being placed on the cover plate 128 and Between the bottom plates 125, the cover plate 128 is used for the user's body part 110 (such as a finger or other part of the body) to touch, and can protect the light emitter 122 and the light detector 124, the bottom plate 125 is used to carry the light emitter 122 and the light detector 124. among them:

Light emitter 122: for emitting light 121, the emitted light 121 has a specific wavelength, and can illuminate the body part 110 of the touch cover 128 through the cover plate 128.

The photodetector 124 is configured to receive the reflected light 123 reflected by the body part 110, and obtain the touch pressure of the body part 110 on the cover plate 128 according to the intensity of the reflected light 123.

It should be noted that the cover plate 128 is not limited to a flat surface, and may also be a shell of various shapes; In terms of materials, materials capable of transmitting light of a specific wavelength, such as a transparent cover plate, a black PE material, or the like, may be selected to enable the light emitted by the light emitter 122 to pass.

The touch pressure detecting device 120 may also include only the light emitter 122 and the light detector 124, and the body part 110 may directly touch the light emitter 122 or may touch the PCB on which the light emitter 122 and the light detector 124 are packaged.

Further, a light blocking member 126 is disposed between the light emitter 122 and the light detector 124 to block the light 121 emitted by the light emitter 122 from directly illuminating the light detector 124 to affect the detection accuracy.

When the light 121 is irradiated to the body part 110 of the person (hereinafter referred to as a finger), the body part 110 absorbs a part of the light, and reflects a part of the light 123, which includes light reflected by tissues such as skin, blood, bones and the like. The light reflected by the tissue of the skin and bone is substantially fixed and does not change with changes in pressure; the light reflected by the tissue of the blood will vary with the volume of blood in the body part 110, ie the body part 110 pairs the cover The pressure of 128 is different, the blood volume will be different, and the intensity of the reflected light will be different.

When the blood volume of the body part 110 is higher, the more light is absorbed, the less light 123 is reflected, and the less light is absorbed, the more light 123 is reflected. The inventors have found through careful research that when the user's finger 110 touches the surface of the device (such as the cover plate 128 capable of transmitting light of a specific wavelength), the blood volume of the touched portion of the finger 110 changes, and as the blood volume of the touched portion decreases. The absorbed light is also reduced, and the reflected light, that is, the reflected light 123 is increased, that is, the touch pressure 118 is increased, the blood volume is decreased, and the intensity of the reflected light 123 is increased. It can be seen that the touch pressure 118 is inversely related to the blood volume and positively correlated with the intensity of the reflected light 123. The change in blood volume in the finger 110 can be detected by detecting the intensity of the reflected light 123, thereby detecting the touch pressure 118.

Here, the blood volume refers to the sum of the blood volumes contained in the blood vessels. As shown in Figure 2, blood consists of static blood 111 and dynamic blood (112, 114). Static blood 111 refers to blood that does not change with systole and relaxation of the heart, and dynamic blood (112, 114) refers to pulsating blood that changes in arterial capillaries as the heart contracts and relaxes. The static blood 111 generally maintains a relatively stable level, while the volume of the dynamic blood (112, 114) changes when the finger is subjected to the touch pressure 118, and when the finger 110 applies the touch pressure 118, the arterial capillaries are squeezed, this pressure is The pressure 116 of the heart's blood transport acts on the capillaries, bringing the blood volume of the capillaries to a new equilibrium. Each pressure value corresponds to a blood volume value, and a change in blood volume is measured to obtain a pressure change. Although, the dynamic blood (112, 114) volume also changes periodically with heart fluctuations, However, such small fluctuations are negligible relative to changes in blood volume caused by the touch pressure 118.

The light ray 121 emitted by the light emitter 122 is preferably light that is easily absorbed by the blood, such as red light, infrared light, or green light, such as 625 nm red light, 840 nm infrared light, 525 nm green light, etc., or alternatively The combination of light. The stronger the absorption ability of the blood to the emitted light 121, the greater the change in the intensity of the reflected light 123 as the blood volume changes, and the better the detection effect, the higher the detection accuracy.

As shown in FIG. 3, the light emitter 122 includes a light emitting unit 202 for controlling the light emission intensity and the light emitting timing of the light emitting unit 202, and a light emitting control unit 204 for controlling under the control of the light emitting control unit 204. Light is emitted. The light emitting unit 202 is preferably a light emitting diode.

The photodetector 124 can quantify the touch pressure based on the intensity of the reflected light by utilizing a relationship in which the reflected light intensity is positively correlated with the touch pressure.

Preferably, the photodetector 124 can convert the reflected light signal into an electrical signal, and the intensity of the reflected light is measured by the intensity of the electrical signal. The intensity of the electrical signal is positively correlated with the intensity of the reflected light, and the electrical signal is enhanced with the reflected light. Enhancement, weakened as the reflected light weakens.

As shown in FIG. 4, the photodetector 124 includes a photosensor 206 and an analysis processing unit 207, wherein: the photosensor 206 is for sensing and receiving reflected light, and converting the reflected optical signal into an electrical signal; and the analysis processing unit 207 is used for powering The signal is analyzed and processed to obtain the strength of the electrical signal, and the touch pressure is quantized according to the strength of the electrical signal.

As shown in FIG. 5, it is a connection diagram of each unit module in the light emitter 122 and the photodetector 124. The analysis processing unit 207 includes a pre-processing module 208, a data acquisition module 210, a data processing module 212, and a feedback adjustment module 214 that are sequentially connected. The pre-processing module 208 is also connected to the photosensor 206 and the feedback adjustment module 214, respectively. The processing module 212 is also coupled to the illumination control unit 204 of the light emitter 122. among them:

The pre-processing module 208 is configured to process the tiny electrical signals converted by the photosensor 206, including filtering the fixed reference signals in the electrical signals and amplifying the electrical signals.

As shown in FIG. 6, the input signal of the pre-processing signal 208 includes a fixed reference signal and a signal reflecting the pressure fluctuation. The fixed reference signal refers to a signal that does not change with changes in blood volume. The shaded part in the figure is a constant signal reflected from the bones and other tissues in the body part, and is reflected as a DC signal in the electrical signal; The returning signal is reflected by the finger pressure as an alternating signal in the electrical signal, which is a useful part of detecting the touch pressure. Pre-processing module Block 208 can implement filtering and amplification functions using devices such as amplifiers, integrators, and the like. After filtering out the fixed reference signal, the signal reflecting the pressure fluctuation is amplified and output, so that the latter module can process only the useful signal portion.

The data acquisition module 210 is configured to perform analog-to-digital conversion on the electrical signal processed by the pre-processing module 208, and convert the electrical signal from an analog signal to a digital signal. The data acquisition module 210 can implement an analog-to-digital conversion function using an ADC (Analog-to-Digital Converter).

The data processing module 212 is configured to analyze the digital signal collected by the processing data acquisition module 210, obtain the strength of the digital signal, and quantize the detection result of the touch pressure according to the intensity of the digital signal by using a positive correlation between the digital signal strength and the touch pressure. The data processing module 212 can employ an MCU (Microcontroller Unit).

In addition, the data processing module 212 controls the feedback adjustment module 214 to adjust the pre-processing according to the analysis processing result, because the different parts of the body (such as different fingers), the blood volume changes of different human bodies under pressure or the characteristics of blood absorption light may be different. The filtering parameters of the module 208 are used to make the detection result more accurate, and the illumination control unit 204 is also controlled to adjust the illumination intensity, the illumination timing, and the like of the illumination unit 202 to ensure that the signal reflected by the body part is effective in the pre-processing module 208. Within the dynamic range. The feedback adjustment module 214 can perform adjustment of the filtering parameters by using a DAC (Digital to Analog Converter).

As shown in FIG. 7, it is a schematic circuit diagram of a specific implementation of the light emitter 122. The illumination control unit 204 includes a driving current source 304. The driving current source 304 drives the illumination unit 202 (such as a light emitting diode) to emit light under the control of the control signal 306. The control signal 306 can be a single pulse signal or a series of pulses. , or other custom signal formats.

As shown in FIG. 8, a schematic circuit diagram of a specific implementation of photodetector 124 (with data processing module 212 omitted). The photoelectric sensor 206 senses the reflected light reflected by the body part to generate an induced current, and the induced current is converted into a voltage signal by a series of processing by the pre-processing module 208, and then sent to the data acquisition module 210 (ADC). The pre-processing module 208 includes a parallel transconductance amplifier 314, a feedback resistor 312 and a capacitor 310. The reference voltage (Vref) of the transconductance amplifier 314 can be adjusted. The feedback resistor 312 can select an appropriate resistance according to the signal strength of the photosensor 206. Value, capacitor 310 is a bandwidth-limited capacitor that limits the operation of the circuit to a reasonable bandwidth. The feedback adjustment module (DAC) is preferably coupled to the same end of the transconductance amplifier 314 via a filter. The data processing module 212 controls the feedback adjustment module (DAC) according to the intensity of the electrical signal 316 collected by the data acquisition module 210 (ADC) to adjust the parameters of the transconductance amplifier 314 at the same end. The voltage Vref is measured (ie, the parameters are filtered out) to ensure that the output of the transconductance amplifier 314 is not saturated.

As shown in FIG. 9, the correspondence relationship between the touch pressure, the blood volume of the touched portion, and the electrical signal detected by the touch pressure detecting means is shown. among them:

As shown in FIG. 9A, the correspondence between the blood volume and the touch pressure: Referring to FIG. 2, when the pressure 110 is applied by the finger 110, the capillary of the artery is squeezed, and the applied pressure 118 acts on the capillary with the pressure 116 of the blood transported by the heart. The blood vessels 112, which flow into the touch site of the finger, are significantly reduced, so that the blood volume of the capillaries reaches a new balance. Each pressure value corresponds to a blood volume value, and the greater the pressure, the smaller the blood volume.

As shown in Fig. 9B, it is a schematic diagram showing the relationship between the blood volume and the electrical signal intensity detected by the touch pressure detecting means. Referring to FIG. 2, when the blood volume becomes smaller under the action of the finger pressure 118, the absorption capacity of the blood to the light 121 emitted by the light emitter 122 is lowered, so that the intensity of the reflected light 123 received by the light detector 124 is increased and converted. As the electrical signal increases, the smaller the blood volume, the larger the electrical signal. It can be seen that the intensity of the reflected light 123 is positively correlated with the touch pressure 118.

As shown in FIG. 9C, the relationship between the touch pressure and the electrical signal detected by the touch pressure detecting means. From the above analysis, as the pressure of the touch increases, the capillaries of the body part touching the cover plate are pressed by the pressure, so that the blood volume in the body part becomes smaller, and the blood absorption ability of the part is weakened. The intensity of the reflected light is enhanced, and finally the electrical signal detected by the photodetector is enhanced, so the electrical signal detected by the touch pressure detecting device is positively correlated with the touch pressure.

The touch pressure detecting device of the present invention can be applied to various electronic devices, such as mobile terminals such as mobile phones and tablet computers; and can be combined with different components on the mobile terminal and applied to different locations of the mobile terminal, such as mobile terminals. The touch panel, the location of the home button, the location of the fingerprint recognition sensor, and the like.

The touch pressure detecting device of the present invention realizes optically by emitting light to a body part having a touch motion and receiving reflected light reflected from blood in the body part, and acquiring a touch pressure generated by the body part according to the intensity of the reflected light. Detect touch pressure. Compared with the traditional capacitance detection method and varistor detection method, this method has the advantages of high detection sensitivity, simple structure, small volume and low cost.

Referring to FIG. 10, an embodiment of a touch pressure detecting method of the present invention is proposed. The method includes the following steps:

S11. Transmit a light having a specific wavelength to a body part touching the through the cover plate.

The emitted light is preferably 625 nm red light, 840 nm infrared light or easily absorbed by blood. The green light of 525 nm, etc., or a combination of the above light.

S12. Receive reflected light reflected from the body part.

In this step S12, after the emitted light is irradiated to a body part (such as a finger), a part of the light is absorbed by the body part, and another part of the light is reflected by the body part, and receives the reflected part of the light, including skin, blood, Light reflected from tissues such as bones.

Preferably, in order to prevent the emitted light from being directly received by the device receiving the reflected light and affecting the detection accuracy, a light blocking member may be disposed between the device that emits the light and the device that receives the reflected light.

S13. Acquire a touch pressure of the body part on the cover according to the intensity of the reflected light.

In the present step S13, the detection result of the touch pressure is quantized based on the intensity of the reflected light by the positive correlation between the touch pressure and the intensity of the reflected light.

In some embodiments, the intensity of the reflected light can be directly detected by the light intensity detecting device in the prior art, and then the detection result of the touch pressure is quantized according to the intensity of the reflected light by using the positive correlation between the reflected light intensity and the touch pressure.

In the embodiment of the present invention, the reflected light signal can be converted into an electrical signal, and the intensity of the reflected light is measured by the intensity of the electrical signal; then the electrical signal is analyzed and processed, and the touch pressure is quantized according to the intensity of the electrical signal. Specifically, as shown in FIG. 11, the following steps are included:

S131. Convert the reflected optical signal into an electrical signal.

Specifically, the photoelectric sensor can be used to sense the reflected light and convert the reflected light signal into an electrical signal.

S132: Filtering the fixed reference signal in the electrical signal and amplifying the electrical signal.

Specifically, an amplifier, an integrator, or the like can be used to perform filtering and amplifying functions of the electrical signal.

The fixed reference signal refers to a signal that does not change with changes in blood volume, and is a constant signal reflected from bones and other tissues in the body part, and is reflected as a DC signal in the electrical signal, and the signal reflected from the blood is reflected. It is embodied as an alternating signal in an electrical signal.

S133. Convert the electrical signal from an analog signal to a digital signal.

Specifically, an ADC can be used to implement analog-to-digital conversion of an electrical signal.

S134. Analyze and process the digital signal, and quantize the touch pressure according to the intensity of the digital signal.

Specifically, the MCU can be used to analyze and process the digital signal collected by the data acquisition module, obtain the intensity of the digital signal, and use the positive correlation between the digital signal strength and the touch pressure to quantify the detection result of the touch pressure according to the intensity of the digital signal.

S135. Adjust a filtering parameter for filtering the fixed reference signal according to the analysis processing result.

Since different parts of the body (such as different fingers), blood volume changes under different pressures of the human body or blood absorption characteristics may be different, the filtering parameters are also adjusted according to the analysis processing results to make the detection result more accurate. Filter out parameters such as voltage parameters.

At the same time, according to the analysis processing result, the illumination intensity, the illumination timing, and the like of the device that emits light can be controlled to ensure that the signal reflected by the body part is within the effective dynamic range of the device operation.

The touch pressure detecting method of the present invention realizes optically by emitting light to a body part having a touch action and receiving reflected light reflected from blood in the body part, and acquiring a touch pressure generated by the body part according to the intensity of the reflected light. Detect touch pressure. Compared with the traditional capacitance detection method and varistor detection method, this method has the advantages of high detection sensitivity, simple structure, small volume and low cost.

It should be noted that the touch pressure detecting method provided in the above embodiment is the same as the touch pressure detecting device embodiment, and the technical features in the device embodiment are applicable in the method embodiments, and details are not described herein again.

It should be understood that the above are only preferred embodiments of the present invention, and thus the scope of the patents of the present invention is not limited thereto, and the equivalent structure or equivalent process transformations made by the contents of the specification and drawings of the present invention may be directly or indirectly applied to Other related technical fields are equally included in the scope of patent protection of the present invention.

Claims

A touch pressure detecting device comprising a light emitter and a light detector, wherein:

The light emitter is configured to emit light and illuminate a body part having a touch action;

The photodetector is configured to receive reflected light reflected by the body part, and acquire a touch pressure generated by the body part according to the intensity of the reflected light.
A touch pressure detecting device according to claim 1, further comprising a cover plate and a bottom plate, said light emitter and said photodetector being interposed between said cover plate and said bottom plate, said body The portion touches the cover plate; the light emitted by the light emitter has a specific wavelength, and the body part can be irradiated through the cover plate.
The touch pressure detecting device according to claim 1, wherein said photodetector comprises a photosensor and an analysis processing unit,

The photosensor is configured to receive reflected light reflected from blood in the body part, and convert the reflected light signal into an electrical signal to measure the intensity of the reflected light by using the intensity of the electrical signal;

The analysis processing unit is configured to perform an analysis process on the electrical signal, and quantify a touch pressure generated by the body part according to an intensity of the electrical signal;

Wherein, the touch pressure is inversely related to the blood volume in the body part, and is positively correlated with the intensity of the reflected light.
The touch pressure detecting device according to claim 3, wherein the analysis processing unit comprises a pre-processing module, a data acquisition module, and a data processing module that are sequentially connected, and the pre-processing module is further configured with the photosensor Connected, where:

The pre-processing module is configured to filter a fixed reference signal in the electrical signal and perform amplification processing on the electrical signal;

The data acquisition module is configured to convert the electrical signal from an analog signal to a digital signal;

The data processing module is configured to analyze and process the digital signal, and quantify the touch pressure generated by the body part according to the intensity of the digital signal.
The touch pressure detecting device according to claim 4, wherein the analysis processing unit further comprises a feedback adjustment module, wherein the feedback adjustment module is respectively connected to the data processing module and the pre-processing module, according to the The analysis processing result of the data processing module adjusts the filtering parameters of the pre-processing module.
The touch pressure detecting device according to claim 4 or 5, wherein the pre-processing module comprises:

A transconductance amplifier, a feedback resistor and a feedback capacitor, the feedback resistor and the feedback capacitor being connected in parallel and connected across an inverting input and an output of the transconductance amplifier.
The touch pressure detecting device according to claim 1, wherein the light emitter comprises a light emitting unit and a light emitting control unit, wherein the light emitting control unit is configured to control a light emitting intensity and a light emitting timing of the light emitting unit, The illumination unit is for emitting light under the control of the illumination control unit.
The touch pressure detecting apparatus according to claim 7, wherein said light emission control unit comprises a drive current source that drives said light emitting unit to emit light under the control of a pulse signal.
The touch pressure detecting device according to any one of claims 1 to 8, wherein the light emitted by the light emitter comprises one or more of red light, infrared light, and green light.
The touch pressure detecting device according to any one of claims 1 to 8, wherein the touch pressure detecting device further comprises a light blocking member disposed between the light emitter and the photodetector.
A touch pressure detecting method, comprising the following steps:

Emitting light to a body part that has a touch action;

Receiving reflected light reflected from blood in the body part;

Obtaining a touch pressure generated by the body part according to the intensity of the reflected light;

Wherein, the touch pressure is inversely related to the blood volume in the body part, and is positively correlated with the intensity of the reflected light.
The touch pressure detecting method according to claim 10, wherein the acquiring the touch pressure generated by the body part according to the intensity of the reflected light comprises:

Converting the reflected light signal into an electrical signal to measure the intensity of the reflected light using the intensity of the electrical signal;

The electrical signal is subjected to an analysis process to quantify the touch pressure generated by the body part based on the intensity of the electrical signal.
The touch pressure detecting method according to claim 11, wherein the analyzing the electrical signal, and quantifying the touch pressure generated by the body part according to the intensity of the electrical signal, comprises:

Filtering a fixed reference signal in the electrical signal and amplifying the electrical signal;

Converting the electrical signal from an analog signal to a digital signal;

The digital signal is analyzed and processed, the touch pressure generated by the body part is quantized according to the intensity of the digital signal, and the filtering parameter for filtering the fixed reference signal is adjusted according to the analysis processing result.