阅读说明：本技术 激光位移传感器 (Laser displacement sensor ) 是由 吴大桥 侴智 郑以磊 黄杰峰 于 2020-09-04 设计创作，主要内容包括：本申请涉及一种激光位移传感器,包括壳体、激光发射组件、感光元件和反光元件。所述壳体包围形成容纳腔。所述激光发射组件设置于所述容纳腔。所述激光发射组件用于向被测物体发射激光。所述感光元件和所述反光元件均设置于所述容纳腔。所述反光元件用于将被所述被测物体反射的所述激光反射至所述感光元件。通过灵活调整所述反光元件在所述容纳腔中的位置和接收所述激光的角度,可以使得所述激光向不同的方向传播。因此可以提高所述感光元件位置调整的灵活性。通过调整所述反光元件和所述感光元件的位置和角度,可以减少所述激光发射组件和所述感光元件之间的距离。进而可以缩小所述激光位移传感器的体积,便于使用和携带。(The application relates to a laser displacement sensor, which comprises a shell, a laser emission assembly, a photosensitive element and a reflecting element. The housing encloses a receiving cavity. The laser emission assembly is arranged in the accommodating cavity. The laser emission assembly is used for emitting laser to an object to be measured. The photosensitive element and the light reflecting element are arranged in the accommodating cavity. The reflecting element is used for reflecting the laser reflected by the measured object to the photosensitive element. By flexibly adjusting the position of the reflecting element in the accommodating cavity and the angle for receiving the laser, the laser can be transmitted to different directions. Therefore, the flexibility of the position adjustment of the photosensitive element can be improved. By adjusting the positions and angles of the light reflecting element and the photosensitive element, the distance between the laser emitting assembly and the photosensitive element can be reduced. And further, the volume of the laser displacement sensor can be reduced, and the laser displacement sensor is convenient to use and carry.)

1. A laser displacement sensor, comprising:

a housing enclosing a receiving cavity;

the laser emission assembly is arranged in the accommodating cavity and used for emitting laser to an object to be measured;

the photosensitive element is arranged in the accommodating cavity; and

the reflecting element is arranged in the accommodating cavity and used for reflecting the laser reflected by the measured object to the photosensitive element so as to reduce the distance between the laser emitting assembly and the photosensitive element.

2. The laser displacement sensor according to claim 1, further comprising a focusing element disposed in the accommodating chamber, wherein the laser light reflected by the object to be measured is irradiated to the reflecting element through the focusing element.

3. The laser displacement sensor according to claim 1, wherein a laser outlet and a laser inlet are provided at the same side of the housing at an interval, the laser emitting assembly emits the laser to the object to be measured through the laser outlet, and the laser reflected by the object to be measured is emitted to the reflecting element through the laser inlet.

4. The laser displacement sensor of claim 3, wherein the photosensitive element is disposed between the laser emitting assembly and the reflective element.

5. The laser displacement sensor of claim 1, wherein the laser emitting assembly comprises:

the laser diode emits the laser and emits the laser through the collimating lens;

and the laser emission control circuit is connected with the laser diode and is used for controlling the working state of the laser diode.

6. The laser displacement sensor as claimed in claim 1, further comprising a controller electrically connected to the laser emitting assembly and the photosensitive element, respectively, wherein the controller is configured to control an operating state of the laser emitting assembly and receive a signal transmitted by the photosensitive element.

7. The laser displacement sensor of claim 6, further comprising a signal conditioning circuit electrically connected between the photosensitive element and the controller for reducing an exposure time of the photosensitive element.

8. The laser displacement sensor of claim 7, wherein the signal conditioning circuit comprises:

the input end of the differential subtraction circuit is electrically connected with the photosensitive element and is used for eliminating useless direct current offset component signals in the signals sent by the photosensitive element;

the input end of the amplifying circuit is electrically connected with the output end of the differential subtraction circuit and is used for amplifying alternating current component signals in the signals sent by the photosensitive element;

and the input end of the active filter circuit is connected with the output end of the amplifying circuit and is used for filtering the alternating current component signal, and the output end of the active filter circuit is electrically connected with the controller.

9. The laser displacement sensor of claim 8, wherein the controller includes an analog-to-digital conversion device, and wherein the output of the source filter circuit is electrically connected to the analog-to-digital conversion device.

10. The laser displacement sensor according to claim 9, further comprising a data storage device, a display device and an input-output device, each electrically connected to the controller.

Technical Field

The invention relates to the technical field of precision measurement, in particular to a laser displacement sensor.

Background

The laser displacement sensor has wide application in the field of industrial automation. The laser displacement sensor uses a laser triangulation distance measuring principle and has the performance characteristics of non-contact measurement, high precision and high response speed.

In recent years, especially with the development of artificial intelligence, the performance requirements of laser displacement sensors are increasing. However, the conventional laser displacement sensor is large in size, inconvenient to carry and inconvenient to use in a narrow space.

Disclosure of Invention

Based on this, it is necessary to provide a laser displacement sensor.

A laser displacement sensor comprising:

a housing enclosing a receiving cavity;

the laser emission assembly is arranged in the accommodating cavity and used for emitting laser to an object to be measured;

the photosensitive element is arranged in the accommodating cavity; and

the reflecting element is arranged in the accommodating cavity and used for reflecting the laser reflected by the measured object to the photosensitive element so as to reduce the distance between the laser emitting assembly and the photosensitive element.

In one embodiment, the laser light source further comprises a focusing element arranged in the accommodating cavity, and the laser light reflected by the object to be measured is irradiated to the reflecting element through the focusing element.

In one embodiment, a laser outlet and a laser inlet are arranged on the same side of the shell at intervals, the laser emitting assembly emits the laser to the object to be measured through the laser outlet, and the laser reflected by the object to be measured is emitted to the reflecting element through the laser inlet.

In one embodiment, the photosensitive element is disposed between the laser emitting assembly and the light reflecting element.

In one embodiment, the laser emitting assembly includes:

the laser diode emits the laser and emits the laser through the collimating lens;

and the laser emission control circuit is connected with the laser diode and is used for controlling the working state of the laser diode.

In one embodiment, the laser device further comprises a controller electrically connected with the laser emitting assembly and the photosensitive element respectively, and the controller is used for controlling the working state of the laser emitting assembly and receiving the signal sent by the photosensitive element.

In one embodiment, the device further comprises a signal conditioning circuit electrically connected between the photosensitive element and the controller for reducing the exposure time of the photosensitive element.

In one embodiment, the signal conditioning circuit comprises:

the input end of the differential subtraction circuit is electrically connected with the photosensitive element and is used for eliminating useless direct current offset component signals in the signals sent by the photosensitive element;

the input end of the amplifying circuit is electrically connected with the output end of the differential subtraction circuit and is used for amplifying alternating current component signals in the signals sent by the photosensitive element;

and the input end of the active filter circuit is connected with the output end of the amplifying circuit and is used for filtering the alternating current component signal, and the output end of the active filter circuit is electrically connected with the controller.

In one embodiment, the controller includes an analog-to-digital conversion device, and the output terminal of the source filter circuit is electrically connected to the analog-to-digital conversion device.

In one embodiment, the system further comprises a data storage device, a display device and an input and output device which are respectively electrically connected with the controller.

The embodiment of the application provides laser displacement sensor includes casing, laser emission subassembly, photosensitive element and reflex reflector element. The housing encloses a receiving cavity. The laser emission assembly is arranged in the accommodating cavity. The laser emission assembly is used for emitting laser to an object to be measured. The photosensitive element and the light reflecting element are arranged in the accommodating cavity. The reflecting element is used for reflecting the laser reflected by the measured object to the photosensitive element. By flexibly adjusting the position of the reflecting element in the accommodating cavity and the angle for receiving the laser, the laser can be transmitted to different directions. The photosensitive element need not be disposed on a linear path of the laser light reflected by the object to be measured. Therefore, the flexibility of the position adjustment of the photosensitive element can be improved. By adjusting the positions and angles of the light reflecting element and the photosensitive element, the distance between the laser emitting assembly and the photosensitive element can be reduced. And further, the volume of the laser displacement sensor can be reduced, and the laser displacement sensor is convenient to use and carry.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions 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 diagram of an internal structure of a laser displacement sensor according to an embodiment of the present disclosure;

FIG. 2 is an optical diagram of a laser displacement sensor provided in one embodiment of the present application;

FIG. 3 is a diagram illustrating the relationship between modules in a laser displacement sensor according to an embodiment of the present disclosure;

FIG. 4 is a diagram illustrating the relationship between the photosensitive element, the timer and the analog-to-digital conversion device according to an embodiment of the present disclosure;

fig. 5 is a schematic diagram of clock, laser emission, and exposure duty cycle provided in an embodiment of the present application.

Description of reference numerals:

the device comprises a laser displacement sensor 10, a housing 100, a light path structure body 101, a containing cavity 110, a laser outlet 120, a laser inlet 130, a photosensitive element 210, a reflecting element 220, a focusing element 230, a laser emitting assembly 240, a laser diode 242, a collimating lens 244, a laser emitting control circuit 246, a controller 300, an analog-digital conversion device 310, a signal conditioning circuit 400, a differential subtraction circuit 410, an amplifying circuit 420, an active filter circuit 430, a data storage device 510, a display device 520, an input-output device 530, a cable 540, a power supply module 550 and a measured object 600.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present application. The first resistance and the second resistance are both resistances, but they are not the same resistance.

It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.

As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.

Referring to fig. 1 and fig. 2, an embodiment of the present application provides a laser displacement sensor 10. The laser displacement sensor 10 includes a housing 100, a laser emitting assembly 240, a light sensing element 210, and a light reflecting element 220. The housing 100 encloses a receiving chamber 110. The laser emitting assembly 240 is disposed in the accommodating chamber 110. The laser emitting assembly 240 is used for emitting laser to the object 600 to be measured. The light sensing element 210 and the light reflecting element 220 are both disposed in the accommodating cavity 110. The light reflecting element 220 is used for reflecting the laser light reflected by the object 600 to be measured to the light sensing element 210. The distance between the laser emitting assembly 240 and the photosensitive element 210 can be reduced by the light reflecting element 220.

The laser displacement sensor 10 may employ a laser triangulation method. The distance measuring principle of the laser triangulation distance measuring method is as follows: the laser beam emitted from the laser emitting assembly 240 is irradiated on the object 600 to be measured. The laser light is reflected by the object 600 to be measured and focused on the photosensitive element 210. When the position of the object 600 to be measured changes, the angle of the laser light received by the photosensitive element 210 changes accordingly. The position of the laser spot on the photosensitive element 210 also differs. Thus, by calculating the amount of movement of the spot position focused on the photosensitive element 210, the displacement of the object 600 to be measured can be obtained.

The shape and material of the housing 100 are not limited. For example, the housing 100 may be a cubic or cylindrical structure. The housing 100 may further include an optical path structure 101. The laser emitting assembly 240, the photosensitive element 210, and the light reflecting element 220 may be fixed to the light path structure body 101, respectively. The optical path structure 101 may be provided with an optical path channel.

In one embodiment, the optical devices such as the laser emitting assembly 240, the photosensitive element 210, and the light reflecting element 220 may be fixed to the optical path structure 101 by screwing. It is understood that the optical path structure body 101 may be formed by mold-open injection molding. The optical path structure body 101 may be preset with different mounting positions to mount different optical devices or electrical devices. The housing 100 may also be open for passage of a cable 540. To connect internal optical or electrical devices.

The material of the housing 100 may be polyester or a metal material. The laser emitting assembly 240 may emit laser light. The photosensitive element 210 can receive the laser light and output a signal according to the position of the laser light on the surface of the photosensitive element 210. The light reflecting member 220 may be a mirror. It is understood that the laser light reflected from the object 600 to be measured is transmitted in a straight line when the light reflecting member 220 is not provided. The photosensitive element 210 can be disposed only in a straight path of the laser light transmission. By providing the light reflecting element 220, the position of the light sensing element 210 in the accommodating cavity 110 can be flexibly adjusted, so that the laser light can be reflected to the light sensing element 210 through the light reflecting element 220. By reducing the distance between the laser emitting assembly 240 and the light sensing element 210, the optical path and the extension length of the light sensing element 210 in the accommodating cavity 110 can be reduced. The volume of the housing 100 can be reduced, and the volume of the laser displacement sensor 10 can be reduced.

The laser displacement sensor 10 provided by the embodiment of the present application includes a housing 100, a laser emitting assembly 240, a photosensitive element 210, and a reflective element 220. The housing 100 encloses a receiving chamber 110. The laser emitting assembly 240 is disposed in the accommodating chamber 110. The laser emitting assembly 240 is used for emitting laser to the object 600 to be measured. The light sensing element 210 and the light reflecting element 220 are both disposed in the accommodating cavity 110. The light reflecting element 220 is used for reflecting the laser light reflected by the object 600 to be measured to the light sensing element 210. By flexibly adjusting the position of the reflecting element 220 in the accommodating cavity 110 and the angle for receiving the laser light, the laser light can be transmitted to different directions. The light sensing element 210 is not necessarily disposed on a straight path of the laser light reflected by the object 600 to be measured. The flexibility of the position adjustment of the photosensitive element 210 can be improved. By adjusting the positions and angles of the light reflecting member 220 and the light sensing member 210, the distance between the laser emitting assembly 240 and the light sensing member 210 can be reduced. Further, the volume of the laser displacement sensor 10 can be reduced, and the laser displacement sensor is convenient to use and carry.

In one embodiment, the photosensitive element 210 may be a CMOS image sensor. The MOS image sensor can be composed of an image sensing unit array, a row driver, a column driver, a time sequence control logic, an AD converter, a data bus output interface, a control interface and the like. These parts may be integrated in the same silicon chip. The CMOS image sensor has the advantages of simple circuit and high precision.

In one embodiment, the laser displacement sensor 10 further comprises a focusing element 230. The collecting element is disposed in the accommodating chamber 110. The laser light reflected by the object 600 to be measured is irradiated to the reflecting member 220 through the focusing member 230. The focusing element 230 may be a light receiving lens. The focusing element 230 can enable light spots reflected by the object under test 600 at different positions in the measurement range to be focused on the photosensitive element 210, i.e. a focused light path is formed.

In one embodiment, the housing 100 is spaced apart from the laser outlet 120 and the laser inlet 130 on the same side. The distance between the laser outlet 120 and the laser inlet 130 is not limited, and can be adjusted according to actual needs. The laser emitting assembly 240 emits the laser to the object 600 through the laser outlet 120. The laser light reflected by the object to be measured 600 is emitted to the light reflecting member 220 through the laser inlet 130. The housing 100 may be a cubic structure. The laser exit port 120 and the laser entrance port 130 may be disposed on the same surface of the cubic structure. The laser exit 120 and the laser entrance 130 may be parallel to one side of the cubic structure. The laser exit port 120 and the laser entrance port 130 may also be disposed at two opposite corners of one face of the cubic structure. It is understood that the above-mentioned positional relationship between the laser outlet 120 and the laser inlet 130 may also take other forms, and is not limited to the forms already mentioned in the above-mentioned embodiments, as long as it can achieve the function of emitting and receiving laser light.

The laser light may be emitted to the object 600 through the laser light outlet 120. The laser light reflected by the object 600 to be measured can be emitted to the reflecting element 220 through the laser inlet 130. The area of the laser exit port 120 may be smaller than the laser entrance port 130. I.e. the area of the laser inlet 130 may be larger. Therefore, when the incident angle of the laser light is greatly changed, the laser light can also be emitted to the light reflecting member 220 through the laser light incident port. The shape of the laser outlet 120 and the laser inlet 130 may be circular, oval, rectangular, etc.

In one embodiment, the photosensitive element 210 is disposed between the laser emitting assembly 240 and the light reflecting element 220. That is, the light sensing element 210, the laser emitting assembly 240 and the light reflecting element 220 are substantially located in a straight line. The laser emitted from the laser emitting assembly 240 is reflected by the object 600 to be measured, and then reflected to the photosensitive element 210 by the reflective element 220. Therefore, after being emitted by the laser emitting assembly 240, the light path is reflected by the object 600 to be measured, and then passes through the photosensitive element 210 to form a substantially triangular structure. The light sensing element 210 does not have to be disposed at an end of the light reflecting element 220 away from the object 600 to be measured, so that the extended length of the housing 100 can be reduced.

In one embodiment, the laser emitting assembly 240 includes a laser diode 242 and a collimating lens 244. The laser diode 242 emits the laser light and emits the laser light through the collimator lens 244. The collimating lens 244 can change the light from each point in the aperture stop into a parallel collimated light beam, thereby improving the measurement accuracy. The laser diode includes Single Heterojunction (SH), Double Heterojunction (DH), and Quantum Well (QW) laser diodes. Compared with a laser, the laser diode has the advantages of high efficiency, small volume and long service life. It is to be understood that the laser emitting assembly 240 may also take other forms, not limited to the forms already mentioned in the above embodiments, as long as it can achieve the function of emitting laser light.

Referring to fig. 3, in one embodiment, the laser emitting assembly 240 may further include a laser emitting control circuit 246. The laser emission control circuit 246 is connected to the laser diode 242. The laser emission control circuit 246 is used for controlling the operating state of the laser diode 242. The laser emission control circuit 246 may control the time for which the laser diode 242 emits laser light, the intensity of the emitted laser light, the duration of the emitted laser light, and the like.

In one embodiment, the laser displacement sensor 10 further comprises a controller 300. The controller 300 is electrically connected to the laser emitting assembly 240 and the photosensitive element 210, respectively. The controller 300 is used for controlling the working state of the laser emitting assembly 240. And receives the signal sent by the photosensitive element 210. The controller 300 may be a single chip Microcomputer (MCU). The controller 300 may control the time the laser emitting assembly 240 emits laser light, the intensity of the emitted laser light, the duration of the emitted laser light, and the like. The controller 300 may control the operating state of the laser diode 242 by controlling the laser emission control circuit 246. After the laser light reflected by the object 600 to be measured is collected by the photosensitive element 210, the photosensitive element 210 may send a signal to the controller 300. The controller 300 may calculate the moving distance of the object 600 according to the signal.

In one embodiment, the laser displacement sensor 10 further includes a signal conditioning circuit 400. The signal conditioning circuit 400 is electrically connected between the photosensitive element 210 and the controller 300. The signal conditioning circuit 400 is used to reduce the exposure time of the photosensitive element 210. When the signal output by the photosensitive element 210 is small, it is usually necessary to increase the exposure time to obtain a valid signal. The signal conditioning circuit 400 can increase the intensity of the signal output by the photosensitive element 210, thereby reducing the exposure time and improving the response speed and detection accuracy of the laser displacement sensor 10.

In one embodiment, the signal conditioning circuit 400 includes a differential subtraction circuit 410, an amplification circuit 420, and an active filtering circuit 430. The input terminal of the differential subtraction circuit 410 is electrically connected to the light sensing element 210. The differential subtraction circuit 410 is used to eliminate unwanted dc offset component signals in the signal sent by the light sensing element 210. Therefore, the resolution of the analog-to-digital conversion device 310 in the controller 300 can be used more efficiently. An input terminal of the amplifying circuit 420 is electrically connected to an output terminal of the differential subtracting circuit 410. The amplifying circuit 420 is configured to amplify an ac component signal in the signal sent by the light sensing element 210. The differential subtraction circuit 410 filters the dc offset component of the signal to leave the ac component signal. By amplifying the ac component signal, the exposure time can be reduced, and the response speed of the laser displacement sensor 10 can be increased. The input terminal of the active filter circuit 430 is connected to the output terminal of the amplifier circuit 420. The active filter circuit 430 is used for filtering the ac component signal, so that the interference of noise signals can be reduced. The output terminal of the active filter circuit 430 is electrically connected to the controller 300. Accordingly, the signal processed by the signal conditioning circuit 400 may be input to the controller 300. The moving distance of the object 600 to be measured can be obtained through the calculation processing of the controller 300.

In one embodiment, the controller 300 includes an analog-to-digital conversion device 310. The output end of the source filter circuit is electrically connected to the analog-to-digital conversion device 310. Analog signals can be converted into digital signals by the analog-to-digital conversion device 310, so that the controller 300 can perform calculation processing conveniently.

In one embodiment, the laser displacement sensor 10 further comprises a data storage device 510, a display device 520, and an input device. The data storage device 510, the display device 520 and the input device are electrically connected to the controller 300, respectively. The data storage 510 may be used to store key data set by a user. The display device 520 may display data and may perform a setting operation through the display device 520. It is understood that the display device 520 may have a touch screen. The display device 520 may also function as an input device for information. The display device 520 may function as a human-computer interaction. The input/output device 530 may be used for inputting a control signal, for example, a high level and a low level may be input to the controller 300, so as to control the operating state of the laser emitting assembly 240 through the controller 300. The input/output device 530 may also output the operation result of the controller 300 and display the operation result on the display device 520. The laser displacement sensor 10 may also include a power module 550. The laser displacement sensor 10 can be powered by the power module 550.

Referring to fig. 4, in an embodiment, a timer may be further disposed in the controller 300. The timer may send a clock signal and an exposure control signal to the light sensing element 210. The exposure control signal may control the exposure timing of the photosensitive element 210. The timer may also send a timing control signal to the analog-to-digital conversion device 310, so as to control the analog-to-digital conversion device 310 to perform analog-to-digital conversion on the signal output by the photosensitive element 210.

Referring to fig. 5, in an embodiment, the controller 300 controls the duty ratio of the laser emitting component 240 to be greater than the duty ratio of the exposure of the photosensitive element 210, so that useless information can be prevented from being collected when the photosensitive element 210 is exposed, and the efficiency of signal collection is prevented from being reduced.

It is understood that the signal conditioning circuit may also take other forms, not limited to the forms mentioned in the above embodiments, as long as it can achieve the functions of reducing the exposure time, and improving the response speed and detection accuracy of the laser displacement sensor 10. Further, although the active filter circuit 430 is used in the above embodiments, other filter circuits may alternatively be used.

In some embodiments, the analog-to-digital converting means 310 includes a comparator for comparing the signal corresponding to the reference component and the signal corresponding to the signal component with the reference signal for AD conversion; and a counter that performs counting in a down-count mode or an up-count mode using the asynchronous counter and holds a count value at the time of completion of comparison in the comparator. However, the AD conversion scheme in these embodiments described above can be applied to any electronic apparatus that uses AD conversion for converting a difference signal component between two signal components, and is not limited to the solid-state imaging device.

For example, by performing AD conversion outside the solid-state imaging device based on an analog pixel signal captured from the solid-state imaging device using a comparator and a counter, it is possible to construct an electronic apparatus that obtains digital data (pixel data) of a true signal component and performs desired digital signal processing based on the pixel data.

Further, the AD converter described in relation to the embodiments need not necessarily be provided as being included in a solid-state imaging device or an electronic apparatus, but may be provided as a separate device in the form of an Integrated Circuit (IC) or an AD conversion module.

In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.

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