CN112190246A

CN112190246A - Wearable device and main body thereof

Info

Publication number: CN112190246A
Application number: CN202011074891.7A
Authority: CN
Inventors: 刘凯
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-10-09
Filing date: 2020-10-09
Publication date: 2021-01-08

Abstract

The present application relates to a wearable device and a main body thereof, the wearable device comprising a main body, a strap and a control circuit; the main body is provided with a PPG sensor and a piezoelectric film sensor; the both ends of bandage are connected respectively in the relative both sides of main part, and when control circuit started piezoelectric film sensor, piezoelectric film sensor was used for detecting the packing force between main part and the user skin, when the packing force was greater than or equal to and predetermines the threshold value, control circuit can start the PPG sensor to make the PPG sensor carry out heart rate to the user and detect, when the packing force was less than and predetermines the threshold value, control circuit output state signal, the information that state signal carried corresponds with wearable equipment's the elasticity of wearing. The utility model provides a wearable equipment and main part thereof can avoid wearable equipment to influence the problem of rhythm of the heart detection accuracy owing to wear the elasticity not good, simultaneously, when the packing force is less than preset threshold value, control circuit output state signal to in time adjust wearable equipment's elasticity.

Description

Wearable device and main body thereof

Technical Field

The application relates to the technical field of wearable equipment, in particular to wearable equipment and a main body thereof.

Background

With the development of mobile technology, many conventional electronic products begin to increase functions in mobile aspects, for example, wearable devices such as smart watches and smart bracelets may be connected to the internet through a smart phone or a home network to display contents such as incoming call information, short messages, news, weather information, and the like. Some intelligent watches that are equipped with the sensor can also realize functions such as monitoring sleep, monitoring heart rate, sedentary warning, running note step, long-range shooing, music broadcast, video recording, compass. For middle-aged and elderly users and sports enthusiasts, it is very important to detect and read information such as heart rate in time.

However, when current wearable equipment carries out heart rate monitoring, wearable equipment dresses tension or loose excessively, and the rhythm of the heart difference that measures is great to when utilizing wearable equipment to carry out daily monitoring, the testing result is great by the influence of wearable equipment self wearing state, and the testing result is inaccurate, does not reach the effect of rhythm of the heart monitoring.

Disclosure of Invention

An embodiment of the present application provides a wearable device and a main body thereof to solve the technical problem that the heart rate of the wearable device is inaccurate.

In one aspect, the present application provides a wearable device comprising:

a main body provided with a PPG sensor and a piezoelectric film sensor;

the two ends of the bandage are respectively connected to the two opposite sides of the main body, and the wearing tightness of the wearable equipment can be adjusted; and

the control circuit is in signal connection with the piezoelectric film sensor and the PPG sensor;

when the control circuit starts the piezoelectric film sensor, the piezoelectric film sensor is used for detecting pressing force between the main body and the skin of the user, wherein when the pressing force is larger than or equal to a preset threshold value, the control circuit can start the PPG sensor so that the PPG sensor can detect the heart rate of the user, when the pressing force is smaller than the preset threshold value, the control circuit outputs a state signal, and information carried by the state signal corresponds to the wearing tightness of the wearable equipment so as to represent the wearing state of the wearable equipment.

In one embodiment, the main body comprises a display screen which is in signal connection with the control circuit, and when the pressing force is smaller than the preset threshold value, the control circuit outputs a state signal to the display screen, so that the display screen displays the wearing state of the wearable device.

In one embodiment, the control circuit is connected with an alarm, when the pressing force is smaller than the preset threshold value, the control circuit outputs a state signal to the alarm, and the alarm gives an alarm according to the state signal to prompt the wearing state of the wearable device.

In one embodiment, the binding band includes a first band body and a second band body, the first band body includes a first connection end and a first free end, the first connection end is connected with the main body, the first free end is provided with a snap fastener, the second band body includes a second connection end and a second free end, the second connection end is connected with the main body, the second band body is provided with a plurality of buckle holes, the buckle holes are arranged at intervals along the length direction of the second band body, and when the snap fastener is opposite to any one of the buckle holes, the snap fastener can be buckled with the corresponding buckle hole.

In one embodiment, the second free end is provided with a loop through which the first free end of the first belt body can pass, and the first belt body and the second belt body are partially overlapped in the wrapping direction of the strap.

In one embodiment, the band has an inner cavity, and the control circuit is electrically connected to a pressurizing module for pressurizing the inner cavity by inflating according to the status signal, wherein at least the inner side of the band is elastically expanded when the inner cavity is pressurized by inflating.

In one embodiment, the pressurizing module is disposed in the inner cavity, or alternatively, the pressurizing module is disposed in the body.

In one embodiment, the material of the binding band is soft rubber, or the material of the inner side of the binding band is soft rubber, and the outer side of the binding band is hard material.

In one embodiment, the main body comprises a transparent cover, the transparent cover is provided with an inner surface and an outer surface which are arranged in a back-to-back mode, when the wearable device is worn by a user, the outer surface of the transparent cover is opposite to the skin of the wearing part of the user, the piezoelectric film sensor is arranged on one side of the inner surface of the transparent cover, and when the outer surface of the transparent cover is pressed against the skin of the user, the transparent cover and the piezoelectric film sensor deform.

In one embodiment, the light transmittance of the piezoelectric film sensor is higher than 93%, and the PPG sensor is capable of performing heart rate detection on the user through the piezoelectric film sensor when the wearable device is worn by the user.

In another aspect, the present application provides a body of a wearable device, connectable to a band, the body being provided with a PPG sensor and a piezoelectric film sensor in signal connection with a control circuit; when the control circuit starts the piezoelectric film sensor, the piezoelectric film sensor is used for detecting pressing force between the main body and the skin of the user, wherein when the pressing force is larger than or equal to a preset threshold value, the control circuit can start the PPG sensor so that the PPG sensor can detect the heart rate of the user, when the pressing force is smaller than the preset threshold value, the control circuit outputs a state signal, and information carried by the state signal corresponds to the wearing tightness of the wearable equipment so as to represent the wearing state of the wearable equipment.

Above-mentioned wearable equipment and main part thereof, utilize the piezoelectric film sensor to detect the packing force between main part and the user skin, when the packing force is greater than or equal to and predetermines the threshold value, control circuit can start the PPG sensor, so that the PPG sensor carries out heart rate detection to the user, just so avoided wearable equipment because wear the not good problem that influences heart rate detection accuracy of elasticity, simultaneously, when the packing force is less than and predetermines the threshold value, control circuit output status signal, the information that status signal carried is corresponding with wearable equipment's the elasticity of wearing, with the wearing state of characterization wearable equipment, and then can be when wearing the elasticity and can not satisfy heart rate detection needs, adjust wearable equipment's elasticity in time.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic cross-sectional view of a wearable device according to an embodiment;

fig. 2 is a schematic diagram illustrating a principle of heart rate detection by a PPG sensor in a wearable device according to an embodiment;

FIG. 3 is a schematic view of a wearable device in another embodiment, wherein the band is in an uninflated state when the band is inflated and deflated to adjust the tightness of the wearable device;

fig. 4 is a schematic view of the wearable device shown in fig. 3 with the strap in an inflated state.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1, in a wearable device 100 according to an embodiment of the present application, the wearable device 100 may be a smart watch or a smart bracelet. The wearable device 100 includes a main body 10, a band 20, and a control circuit (not shown).

Both ends of the band 20 are respectively connected to opposite sides of the main body 10 so that the main body 10 is fixed to a limb of a user, such as a limb, etc., by the band 20. It will be appreciated that the strap 20 may secure the body 10 at any location of the user where securement is desired, not just to the extremities. The main body 10 may be made of non-metal materials such as plastic, rubber, silica gel, wood or ceramic, and the main body 10 may also be made of metal materials such as stainless steel, aluminum alloy or magnesium alloy. The main body 10 may have a square structure, a circular structure, or other polygonal structures, and is not particularly limited herein.

The main body 10 has an accommodating space 10a formed therein to accommodate devices such as a main control board, a battery, etc. through the accommodating space 10a, and the control circuit may be integrated with the main control board.

In some embodiments, the main body 10 includes a housing 11 and a display 12, and the display 12 is connected to the housing 11 to form the accommodating space 10 a. It should be noted that the main body 10 does not necessarily have to be provided with the display 12, and may be provided according to actual needs. For example, when information needs to be displayed using the wearable device 100, the display screen 12 may be configured in the main body 10. For another example, the wearable device 100 is connected to a smart device with a display function, such as a mobile phone or a tablet computer, through wireless communication, and transmits data to the smart device, and the smart device is used to display information.

In some embodiments, the body 10 is provided with a PPG (Photo plethysmo graph) sensor and a piezoelectric film sensor 10b, both of which are in signal connection with the control circuit, so that the PPG sensor and the piezoelectric film sensor 10b can be activated in due course by the control circuit.

As shown in fig. 2, the PPG sensor includes a PD (photo Diode) and an LED (Light Emitting Diode), when the PPG sensor is used to detect the heart rate, Light emitted by the LED is reflected by blood and tissue of the human body, and then the PD receives Light reflected by the blood and tissue of the human body, and the physiological parameters of the human body are traced by detecting the difference of the intensities of the reflected Light absorbed by the blood and tissue of the human body. Because the periodic pulsation of the heart enables the systemic arterial blood vessels to generate periodic contraction and relaxation, the contraction and relaxation is transmitted to systemic arterioles through the aortic blood vessels and then transmitted to skin arterial capillaries (capillaries close to one side of the arterioles), so that the optical signals received by the PD change with the pulsation of the heart, and the heart rate detection is realized.

When the control circuit activates the piezoelectric film sensor 10b, the piezoelectric film sensor 10b is used to detect the pressing force between the main body 10 and the skin of the user.

Since the wearable device 100 is worn by the user with different tightness, the body 10 and the skin of the user are pressed with different degrees, i.e., different pressing forces. More specifically, when the wearing state of the wearable device 100 is too loose, there may be a gap between the body 10 and the skin of the user or just contact is maintained, and the pressing force between the two is small. The piezoelectric thin film sensor 10b is an electrical component based on the piezoelectric effect, and when some dielectrics are deformed by an external force in a certain direction, polarization phenomenon is generated inside the dielectrics to generate opposite positive and negative charges on two opposite surfaces, and the piezoelectric thin film sensor 10b generates an electrical signal along with the change of the deformation quantity. When the external force is removed, it returns to an uncharged state, and this phenomenon is called the positive piezoelectric effect.

Through the detection of the pressing force between the main body 10 and the skin of the user by the piezoelectric film sensor 10b, the degree of adhesion between the main body 10 and the skin of the user can be accurately reflected, so that when the heart rate detection needs to be performed by using the PPG sensor of the wearable device 100, whether the wearable device 100 is in a proper wearing state can be determined by the piezoelectric film sensor 10b, and the accuracy of the heart rate detection is ensured.

Specifically, when the pressing force is greater than or equal to a preset threshold value, the control circuit can start the PPG sensor to enable the PPG sensor to perform heart rate detection on the user, and when the pressing force is less than the preset threshold value, the control circuit outputs a status signal, wherein information carried by the status signal corresponds to the wearing tightness of the wearable device 100 to represent the wearing state of the wearable device 100.

It should be noted that the preset threshold is set according to a pressing force between the main body 10 and the skin of the user when the PPG sensor can accurately detect the heart rate of the user. For example, in some embodiments, when the wearable device 100 is worn by the user, if the pressing force between the subject 10 and the skin of the user is less than 5N, the PPG sensor cannot accurately detect the heart rate, and only if the heart rate detected by the PPG sensor is close to actual when the pressing force between the subject 10 and the skin of the user is greater than or equal to 5N, the preset threshold may be set to 5N, so as to measure whether the wearable device 100 is in a wearing state suitable for heart rate testing.

When the wearable device 100 is adopted to check the heart rate, whether the wearable device 100 is in a wearing state suitable for heart rate testing can be determined by detecting pressing force between the main body 10 and the skin of the user through the piezoelectric film sensor 10b, and when the pressing force is determined to be larger than or equal to a preset threshold value, the control circuit can start the PPG sensor, so that the PPG sensor can more accurately detect the heart rate, and the problem that the detected result of the wearable device 100 is inaccurate under the condition that the wearing state is not good is avoided. Meanwhile, when the pressing force is smaller than a preset threshold value, the control circuit outputs a state signal so as to adjust the wearing state of the wearable device 100 in time and meet the requirement that the PPG sensor accurately detects the heart rate.

In some embodiments, the wearable device 100 is used as an intelligent wearable device, which may be a device in which a user actively starts a heart rate detection mode by a key, a language, a gesture, or a touch operation, and triggers the control circuit to start the piezoelectric film sensor 10b, or may be a device in which the control circuit starts the piezoelectric film sensor 10b to detect a pressing force between the main body 10 and the skin of the user when the wearable device 100 calls an application related to "reading heart rate" or "motion state".

In some embodiments, the display screen 12 of the main body 10 may be used to display the wearing state of the wearable device 100. Specifically, the display screen 12 is in signal connection with the control circuit, and when the pressing force is smaller than the preset threshold value, the control circuit outputs a status signal to the display screen 12, so that the display screen 12 displays the wearing status of the wearable device 100. Therefore, the user can know the wearing state of the wearable device 100 in time according to the content displayed by the display screen 12, so as to adjust the wearing tightness of the wearable device 100 according to the requirement.

In some embodiments, the control circuit is connected to an alarm, and when the pressing force is smaller than a preset threshold value, the control circuit outputs a status signal to the alarm, and the alarm gives an alarm according to the status signal to prompt the wearing status of the wearable device 100. With this arrangement, when the wearing state of the wearable device 100 is not suitable for heart rate detection, the user can be reminded to adjust the wearing state of the wearable device 100 in time through the alarm. The alarm may be a sound-emitting element such as a buzzer or a speaker, or may be an audible or visual alarm. The type of the alarm is not limited herein, as long as the alarm can send out an alarm signal according to the state signal output by the control circuit to remind the user to adjust the wearing tightness of the wearable device 100.

It should be noted that there are many possibilities for adjusting the tightness of the wearable device 100.

For the sake of easy understanding, the wearing tightness will be described below by taking as an example the case where the band 20 and the main body 10 enclose a ring-shaped wearing position 30 through which the user's wrist passes.

In some embodiments, as shown in fig. 1, the band 20 can change the tightness of the wearable device 100 by adjusting the encircling length of the band 20 such that the size of the annular wearing position 30 changes.

The band 20 is divided into two sections, each of the two sections of bands 20 has one end connected to the main body 10, the ends of the two sections of bands 20 facing away from the main body 10 can be fastened, and the two fastened sections of bands 20 and the main body 10 together enclose the annular wearing position 30, so that the requirement of wearing the wearable device 100 to the wrist or arm of the user or other parts of the body can be met by using the annular wearing position 30.

Specifically, the strap 20 includes a first band 21 and a second band 22. The first strap 21 and the second strap 22 are respectively connected to two sides of the main body 10, and it is understood that the first strap 21 and the second strap 22 may be symmetrically disposed or asymmetrically disposed, and are not limited herein. The first strap 21 and the second strap 22 can be secured to each other such that the wearable device 100 is secured to a limb of a user.

The first tape body 21 includes a first connection end 21a and a first free end 21 b. The first connecting end 21a is connected to the housing 11, the first free end 21b is provided with a snap fastener 211, the second belt body 22 is provided with a plurality of fastening holes 221, and the plurality of fastening holes 221 are arranged at intervals along the length direction of the second belt body 22. When the snap fastener 211 is opposite to any one of the buckle holes 221, the snap fastener 211 can be buckled to the corresponding buckle hole 221, so that the encircling length of the first belt body 21 and the second belt body 22 can be adjusted by matching the snap fastener 211 with the buckle hole 221 at different positions, and the wearing tightness of the wearable device 100 can be adjusted by the strap 20.

For convenience of understanding, one end of the second tape body 22 connected to the main body 10 is referred to as a "second connection end 22 a", and particularly, the second tape body 22 includes a second connection end 22a and a second free end 22 b. The second connection end 22a is connected to the main body 10, and the second free end 22b is provided with a band loop 222, through which the first free end 21b of the first band body 21 can pass, and so that the first band body 21 and the second band body 22 are partially overlapped in the winding direction of the band 20. Because the belt ring 222 on the second free end 22b is sleeved on the first belt body 21, the second free end 22b is prevented from tilting relative to the first belt body 21, which affects the overall wearing effect of the binding belt 20.

In other embodiments, as shown in fig. 3 and 4, the band 20 may have a one-piece structure, and both ends of the band 20 are connected to the body 10. The band 20 has an inner cavity (not shown) that is inflated or deflated, and the band 20 changes the size of the wearing position 30 enclosed by the main body 10 in such a way as to expand or contract, so as to adjust the wearing tightness of the wearable device 100.

Specifically, the structure for inflating and deflating the band 20 may be a pressurizing module, that is, the wearable device 100 is configured with the pressurizing module, and when the wearable device 100 is worn loose and the wearing position 30 needs to be tightened, the pressurizing module inflates the inner cavity of the band 20, so that at least the inner side of the band 20 is elastically expanded, and the wearable device 100 is in a proper wearing state.

The pressurizing module may be disposed in the inner cavity of the band 20, or may be disposed in the main body 10, as long as the pressurizing module is capable of inflating and deflating the band 20 to tighten or loosen the wearing position 30 defined by the band 20 and the main body 10.

The material of the binding band 20 is soft rubber, so that when the inner cavity of the binding band 20 is inflated, the binding band 20 can expand to tighten the wearing position 30. Accordingly, when the inner cavity of the band 20 is deflated, the band 20 made of soft rubber material can be deformed to relax the wearing position 30.

In other embodiments, the strap 20 need not be made of soft rubber for the entire structure, as long as the strap 20 can be partially expanded or contracted to adjust the size of the wearing position 30. For example, the material of the inner side 20a of the strap 20 is soft rubber, and the outer side 20b of the strap 20 is hard material, by this arrangement, the material of the outer side 20b of the strap 20 is hard, and the material of the inner side 20a of the strap 20 is soft, so that when the inner cavity of the strap 20 is inflated, the strap 20 is more easily expanded toward the side where the inner side 20a is located, and the outer side 20b which is hard in material can not be deformed as much as possible, so that the overall size of the strap 20 can be kept small, and meanwhile, the deformation requirement of the side where the inner side 20a of the strap 20 is located to a greater extent can be met, and the wearing tightness of the wearable device 100 can be adjusted in a large range.

It should be noted that, in the implementation mode that the wearing tightness of the wearable device 100 is adjusted by inflating and deflating the inner cavity of the band 20 through the pressurizing module, the pressurizing module may be electrically connected to the control circuit, when the pressing force is smaller than a preset threshold value, the control circuit outputs a state signal, and the pressurizing module inflates and pressurizes the inner cavity of the band 20 according to the state signal, so that the wearable device 100 is adjusted to a suitable wearing state, so that the PPG sensor can perform heart rate detection on the user in a suitable wearing state, and accuracy of a heart rate detection result is ensured.

Referring again to fig. 1, in some embodiments, the main body 10 includes a transparent cover 13, the transparent cover 13 has an inner surface 13a and an outer surface 13b opposite to each other, when the wearable device 100 is worn by a user, the outer surface 13b of the transparent cover 13 is opposite to the skin of the wearing part of the user, the piezoelectric film sensor 10b is disposed on the side of the inner surface 13a of the transparent cover 13, and when the outer surface 13b of the transparent cover 13 is pressed against the skin of the user, the transparent cover 13 and the piezoelectric film sensor 10b deform. Under this kind of structural style, transparent cover 13 can enough be as the installation carrier of piezoelectric film sensor 10b, realizes piezoelectric film sensor 10 b's stable installation, simultaneously, and the printing opacity lid also can adapt to the printing opacity needs of the PPG sensor of setting in main part 10 to the PPG sensor carries out heart rate detection to the user.

The light transmittance of the piezoelectric thin film sensor 10b is higher than 93%, so that the piezoelectric thin film sensor 10b has good light transmittance to meet the light transmittance requirement of the PPG sensor. In particular, the PPG sensor is able to perform heart rate detection on the user through the piezoelectric film sensor 10b when the wearable device 100 is worn by the user.

The transparent cover 13 may be made of glass or transparent plastic, and is not limited herein.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A wearable device, comprising:

a main body provided with a PPG sensor and a piezoelectric film sensor;

2. The wearable device of claim 1, wherein the body comprises a display screen in signal communication with the control circuit, and wherein the control circuit outputs a status signal to the display screen when the compressive force is less than the predetermined threshold value, such that the display screen displays the wearing status of the wearable device.

3. The wearable device according to claim 1, wherein the control circuit is connected with an alarm, when the pressing force is smaller than the preset threshold value, the control circuit outputs a status signal to the alarm, and the alarm gives an alarm according to the status signal to prompt the wearing status of the wearable device.

4. The wearable device according to claim 2 or 3, wherein the strap includes a first strap and a second strap, the first strap includes a first connection end and a first free end, the first connection end is connected to the main body, the first free end is provided with a snap fastener, the second strap includes a second connection end and a second free end, the second connection end is connected to the main body, the second strap is provided with a plurality of fastening holes, the fastening holes are arranged at intervals along a length direction of the second strap, and when the snap fastener is opposite to any one of the fastening holes, the snap fastener can be fastened to the corresponding fastening hole.

5. The wearable device according to claim 4, wherein the second free end is provided with a band loop through which the first free end of the first band can pass, and such that the first band and the second band partially overlap in a wrapping direction of the band.

6. The wearable device of claim 1, wherein the strap has an interior cavity, the control circuit is electrically connected to a pressurization module configured to inflate the interior cavity based on the status signal, wherein the strap is elastically expanded at least on an inner side when the interior cavity is inflated.

7. The wearable device according to claim 6, wherein the pressurization module is disposed at the inner cavity or the body.

8. The wearable device according to claim 6, wherein the strap is made of soft rubber, or the inner side of the strap is made of soft rubber and the outer side of the strap is made of hard material.

9. The wearable device according to claim 1, wherein the body comprises a transparent cover, the transparent cover has an inner surface and an outer surface that are opposite to each other, when the wearable device is worn by a user, the outer surface of the transparent cover is opposite to skin of a wearing part of the user, the piezoelectric film sensor is disposed on one side of the inner surface of the transparent cover, and when the outer surface of the transparent cover is pressed against the skin of the user, the transparent cover and the piezoelectric film sensor deform.

10. The wearable device of claim 9, wherein the piezoelectric film sensor has a light transmittance higher than 93%, and wherein the PPG sensor is capable of heart rate detection for a user through the piezoelectric film sensor when the wearable device is worn by the user.

11. A main body of a wearable device can be connected with a bandage, and is characterized in that the main body is provided with a PPG sensor and a piezoelectric film sensor which are in signal connection with a control circuit; when the control circuit starts the piezoelectric film sensor, the piezoelectric film sensor is used for detecting pressing force between the main body and the skin of the user, wherein when the pressing force is larger than or equal to a preset threshold value, the control circuit can start the PPG sensor so that the PPG sensor can detect the heart rate of the user, when the pressing force is smaller than the preset threshold value, the control circuit outputs a state signal, and information carried by the state signal corresponds to the wearing tightness of the wearable equipment so as to represent the wearing state of the wearable equipment.

12. The body of claim 11, wherein the body comprises a transparent cover having an inner surface and an outer surface opposite to each other, the outer surface of the transparent cover is opposite to the skin of the user when the wearable device is worn by the user, the piezoelectric film sensor is disposed on the inner surface of the transparent cover, and the transparent cover and the piezoelectric film sensor deform when the outer surface of the transparent cover is pressed against the skin of the user.

13. The body of claim 12, wherein the piezoelectric film sensor has a light transmittance of greater than 93%, and wherein the PPG sensor is capable of heart rate detection for a user through the piezoelectric film sensor when the wearable device is worn by the user.