Disclosure of Invention
The application aims to provide an assembly platform, an assembly method and a backlight module of a lamp strip, which realize the accurate alignment of the lamp strip by electromagnetic force, are not influenced by the length of a back plate lampshade, and improve the assembly efficiency.
In a first aspect, an embodiment of the present application provides an assembly platform for assembling a light bar to a back plate of a backlight module, the light bar including a flexible circuit board, a plurality of light emitting elements disposed on the flexible circuit board, and a plurality of first permanent magnetic members disposed on a side of the flexible circuit board away from the plurality of light emitting elements, the back plate being provided with a lamp housing for accommodating the light bar, the assembly platform comprising: the frame comprises a bottom plate and side plates surrounding the periphery of the bottom plate, and a space for accommodating the back plate is formed between the bottom plate and the side plates; the first electromagnetic pieces are arranged on the bottom plate in an array mode along the row direction and the column direction, and can generate repulsive force with the first permanent magnetic pieces of the light bar when the first electromagnetic pieces are electrified so that the light bar is suspended at a preset height; and the second electromagnetic parts are arranged on the pair of side plates opposite to each other along the row direction and are distributed at intervals along the column direction, and the second electromagnetic parts can generate magnetic attraction force and repulsive force which are alternately changed in sequence with the first permanent magnetic parts when being electrified so as to drive the lamp strip to move to the lamp shade of the back plate.
In one possible embodiment, the front projection of the light bar on the base plate covers the front projections of the two rows of first electromagnetic members on the base plate; each pair of second electromagnetic members is arranged corresponding to one row of first electromagnetic members.
In one possible embodiment, the first electromagnetic member and the first permanent magnetic member are disk-shaped structural members; and/or the second electromagnetic member is a strip-shaped structural member.
In one possible embodiment, the assembly platform further comprises a hall sensor and a controller, the hall sensor is disposed on the base plate and located between each two adjacent first electromagnetic members, the hall sensor sends a first electrical signal to the controller when sensing the position of the light bar, and the controller is configured to control the first electromagnetic member and the second electromagnetic member at corresponding positions to be energized according to the first electrical signal.
In one possible embodiment, a driving circuit layer is further disposed on the base plate, and the first electromagnetic member, the second electromagnetic member, the controller, and the hall sensor are electrically connected to the driving circuit layer, respectively.
In a second aspect, an embodiment of the present application further provides a method for assembling a light bar, which is applied to an assembling platform of the light bar as described above, where the assembling method includes: placing the back plate on a frame of the assembly platform; placing the light bar on a bottom plate of the frame; the first electromagnetic members and the second electromagnetic members are controlled to be electrified, repulsive force is generated between the first electromagnetic members and the first permanent magnetic members of the lamp strip, so that the lamp strip is suspended at a preset height, and magnetic attraction and repulsive force which are alternately changed in sequence are generated between the second electromagnetic members and the first permanent magnetic members, so that the lamp strip is driven to move to the lampshade of the backboard.
In one possible embodiment, the assembly platform further includes a hall sensor and a controller, the hall sensor being disposed on the base plate and located between each adjacent two first electromagnetic members, the controlling the energizing of the plurality of first electromagnetic members and the plurality of pairs of second electromagnetic members including: the Hall sensor sends a first electric signal to the controller when sensing the position of the light bar, and the controller controls the first electromagnetic piece and the second electromagnetic piece at corresponding positions to be electrified according to the first electric signal.
In one possible embodiment, the lamp shade of the back plate is provided with a plurality of second permanent magnetic pieces, the second permanent magnetic pieces can generate magnetic attraction force with the first permanent magnetic pieces of the lamp strip, and after the lamp strip moves to the lamp shade of the back plate, the assembling method further comprises: adsorbing the first permanent magnetic piece and the second permanent magnetic piece of the light bar together; controlling the first electromagnetic pieces and the second electromagnetic pieces to be powered off; and removing the backboard and the lamp strip.
In a third aspect, an embodiment of the present application further provides a backlight module, including: a back plate, one end of which is provided with a lampshade; and the lamp strip is accommodated in the lamp shade and comprises a flexible circuit board, a plurality of light-emitting elements arranged on the flexible circuit board and a plurality of first permanent magnetic pieces arranged on one side of the flexible circuit board away from the light-emitting elements.
In one possible embodiment, the lamp housing is further provided with a plurality of second permanent magnet pieces, and the second permanent magnet pieces are capable of generating magnetic attraction force with the first permanent magnet pieces.
According to the assembly platform, the assembly method and the backlight module of the light bar, provided by the embodiment of the application, the first permanent magnetic pieces are arranged on the light bar, the plurality of first electromagnetic pieces distributed in an array are arranged on the bottom plate of the frame of the assembly platform, and the plurality of pairs of second electromagnetic pieces are arranged on the side plates of the frame, so that the plurality of first electromagnetic pieces and the plurality of first permanent magnetic pieces generate repulsive force when being electrified, the light bar is suspended at a preset height, and meanwhile, the plurality of pairs of second electromagnetic pieces and the first permanent magnetic pieces can generate magnetic attraction force and repulsive force which are alternately changed in sequence when being electrified, so that the light bar is driven to move to the lampshade of the back plate. Because need not artifical equipment, only can remove the lamp strip to the preset position of lamp shade through electromagnetic force, realize the accurate counterpoint of lamp strip, do not receive the length influence of the lamp shade of backplate, greatly improved the position accuracy and the packaging efficiency of lamp strip.
Detailed Description
Features and exemplary embodiments of various aspects of the application are described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the application. It will be apparent, however, to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the application by showing examples of the application. In the drawings and the following description, at least some well-known structures and techniques have not been shown in detail in order not to unnecessarily obscure the present application; also, the size of the region structures may be exaggerated for clarity. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
Fig. 1 shows a schematic structural diagram of a backlight module according to an embodiment of the present application; fig. 2 is a schematic diagram illustrating a structure of a light bar of the backlight module in fig. 1.
As shown in fig. 1 and fig. 2, an embodiment of the present application provides a backlight module, which includes a back plate 1 and a light bar 2.
One end of the back plate 1 is provided with a lamp shade 10, the lamp strip 2 is accommodated in the lamp shade 10, and the lamp strip 2 comprises a flexible circuit board 21, a plurality of light-emitting elements 22 arranged on the flexible circuit board 21 and a plurality of first permanent magnetic pieces 23 arranged on one side of the flexible circuit board 21 away from the plurality of light-emitting elements 22.
Alternatively, the material of the back plate 1 may be a non-magnetically conductive metal material, such as any one of aluminum plate, aluminum alloy plate or galvanized steel, and is manufactured by a stamping process. The metal material has better ductility, and can protect the backlight module from being broken easily under the impact of external force. The back plate 1 may also be made of plastic material, such as polyimide, polycarbonate, polyethersulfone, polyethylene terephthalate, polyethylene, etc., so as to reduce the weight of the backlight module and reduce the cost of the backlight module.
Alternatively, the number of the first permanent magnetic pieces 23 is equal to the number of the light emitting elements 22, and the positions are in one-to-one correspondence. The first permanent magnetic member 23 is made of neodymium-iron-boron magnets, and the first permanent magnetic member 23 can be adhered to one side of the flexible circuit board 21, which faces away from the plurality of light-emitting elements 22, through high-temperature-resistant structural adhesive.
In this embodiment, the backlight module is of a side-in structure, and the lamp cover 10 is disposed at one end of the back plate 1 for accommodating the light bar 2. In order to prevent the light leakage of the light emitting element 22 on the light bar 2, the light cover 10 generally has a long and narrow opening structure, which is affected by the visual field of the light cover 10 in the related art, the longer the opening length is, the more unable to accurately align the light bar 2, especially when the light emitting element 22 is disposed on the flexible circuit board 21, the problem that two sides of the light bar 2 are attached to the bottom of the light cover 10 and the middle is unable to be attached to the light cover 10 may be caused. Therefore, the electromagnetic force provided by the assembly platform of the light bar can realize the accurate alignment of the light bar 2, which is not affected by the length of the lampshade 10 of the backboard 1, and the assembly efficiency is improved.
The following describes in detail a specific structure of an assembly platform for a light bar according to an embodiment of the present application with reference to the accompanying drawings.
Fig. 3 is a schematic diagram showing an assembly effect structure of an assembly platform of a light bar and a backlight module according to an embodiment of the present application; FIG. 4 shows a schematic top view of the assembly platform of the light bar shown in FIG. 3; fig. 5 shows a longitudinal cross-section of the assembly platform of the light bar shown in fig. 4.
As shown in fig. 3 to 5, an assembling platform for assembling a light bar 2 to a back plate 1 of a backlight module according to an embodiment of the present application includes: the frame 100, a plurality of first electromagnetic members 200, and a plurality of pairs of second electromagnetic members 300.
The frame 100 includes a bottom plate 101 and a side plate 102 surrounding the bottom plate 101, and a space for accommodating the back plate 1 is formed between the bottom plate 101 and the side plate 102.
The first electromagnetic members 200 are disposed on the bottom plate 101 in an array along the row direction X and the column direction Y, and the first electromagnetic members 200 can generate a repulsive force with the first permanent magnetic members 23 of the light bar 2 when energized, so that the light bar 2 is suspended at a preset height.
The plurality of pairs of second electromagnetic members 300 are disposed on the pair of side plates 102 opposite to each other along the row direction X and are distributed at intervals along the column direction Y, and when the plurality of pairs of second electromagnetic members 300 are energized, magnetic attraction force and repulsive force can be generated between the plurality of pairs of second electromagnetic members 300 and the first permanent magnetic members 23 in turn alternately, so as to drive the light bar 2 to move to the light shade 10 of the back plate 1.
As shown in fig. 4, the cross-sectional shape of the frame 100 is rectangular, and the longitudinal direction thereof is the column direction Y and the width direction thereof is the row direction X. The frame 100 includes three side plates 102 provided on the peripheral side of the bottom plate 101, and one opening. The dashed box 1 represents the back plate 1, the dashed box 2 represents the light bar 2, and the back plate 1 and the light bar 2 enter the frame 100 from the open side.
The plurality of first electromagnetic members 200 are disposed on the bottom plate 101 in an array along the row direction X and the column direction Y, and when the power is applied, the plurality of first electromagnetic members 200 can generate a repulsive force with the plurality of first permanent magnetic members 23 of the light bar 2, so that the light bar 2 is suspended at a preset height. The preset height is aligned with the preset mounting position of the light bar 2 on the lamp housing 10 of the back plate 1. The repulsive force needs to be greater than the weight of the light bar 2 itself to suspend the light bar 2 at a predetermined height.
The pairs of second electromagnetic members 300 are disposed on the pair of side plates 102 opposite to each other along the row direction X and are distributed at intervals along the column direction Y, and when the current is applied, the pairs of second electromagnetic members 300 can generate magnetic attraction force and repulsive force which are alternately changed in sequence with the first permanent magnetic members 23, so as to drive the light bar 2 to move to the lampshade 10 of the back plate 1.
According to the assembly platform and the backlight module for the light bar provided by the embodiment of the application, the first permanent magnetic pieces 23 are arranged on the light bar 2, the plurality of first electromagnetic pieces 200 distributed in an array are arranged on the bottom plate 101 of the frame 100 of the assembly platform, and the plurality of pairs of second electromagnetic pieces 300 are arranged on the side plate 102 of the frame 100, so that the plurality of first electromagnetic pieces 200 generate repulsive force with the plurality of first permanent magnetic pieces 23 when being electrified, the light bar 2 is suspended at a preset height, and meanwhile, the plurality of pairs of second electromagnetic pieces 300 can generate magnetic attraction force and repulsive force which are alternately changed with the first permanent magnetic pieces 23 in sequence when being electrified, so that the light bar 2 is driven to move to the lampshade 10 of the backboard 1. Because no manual assembly is needed, the lamp strip 2 can be moved to the preset position of the lamp shade 10 only by electromagnetic force, so that the accurate alignment of the lamp strip 2 is realized, the influence of the length of the lamp shade 10 of the backboard 1 is avoided, and the position accuracy and the assembly efficiency of the lamp strip 2 are greatly improved.
In some embodiments, the lamp shade 10 is pre-coated with glue, and the lamp strip 2 can be adhered to the glue after moving to the lamp shade 10. Further alternatively, after the light bar 2 moves in place, a crimping process may be added to improve the adhesion effect of the light bar 2 and the lamp shade 10.
In some embodiments, as shown in fig. 1 and 3, the lamp housing 10 is further provided with a plurality of second permanent magnetic members 11, and the second permanent magnetic members 11 are capable of generating magnetic attraction force with the first permanent magnetic members 23. The second permanent magnetic pieces 11 are made of neodymium iron boron magnets, the second permanent magnetic pieces 11 are arranged at intervals along the extending direction of the light bar 2, and the second permanent magnetic pieces 11 correspond to the first permanent magnetic pieces 23 one by one.
The second permanent magnet 11 is rectangular in shape and has the same height as the first permanent magnet 23 of the light bar 2. The polarities of the sides of the first permanent magnet piece 23 and the second permanent magnet piece 11 which are in contact with each other are opposite, wherein the polarity of either one is N pole, and the polarity of the other is S pole. In the assembly and use process of the product, the first permanent magnet piece 23 and the second permanent magnet piece 11 are always adsorbed together, so that the lamp strip 2 is firmly fixed, and compared with the glue bonding scheme, the assembly reliability of the lamp strip 2 is improved.
In addition, glue is easy to degum when heating is serious, and magnetic force adsorption can improve the radiating effect, and the magnetic force between the glue and the strip is not influenced, so that the strip is more environment-friendly, and the assembly reliability of the lamp strip 2 is further improved.
In some embodiments, the first electromagnetic member 200 and the first permanent magnetic member 23 are both disk-shaped structures, so as to generate a stable repulsive force therebetween. In some embodiments, the second electromagnetic member 300 is an elongated structural member.
In some embodiments, the front projection of the light bar 2 on the base plate 101 covers the front projection of two rows of the first electromagnetic members 200 on the base plate 101, and each pair of the second electromagnetic members 300 is disposed corresponding to one row of the first electromagnetic members 200.
The plurality of first electromagnetic members 200 are arranged on the bottom plate 101 in an array manner, wherein four first electromagnetic members 200 arranged in two rows and two columns form an electromagnetic control unit. In one electromagnetic control unit, the magnitude of electromagnetic force can be controlled by varying the magnitude of its coil current. The front projection of the light bar 2 on the bottom plate 101 covers the front projection of the two rows of first electromagnetic members 200 on the bottom plate 101, so that repulsive force generated by a plurality of electromagnetic control units is greater than the gravity of the light bar 2, and the suspension effect of the light bar 2 is realized. Each pair of second electromagnetic members 300 is disposed corresponding to one row of first electromagnetic members 200, so as to determine the coordinate position of the light bar 2, and control the moving distance of the light bar 2.
FIG. 6 shows a schematic view of the magnetic force distribution of the first electromagnetic member in the assembly platform shown in FIG. 4; fig. 7 shows a schematic diagram of the magnetic force distribution of the second electromagnetic member in the assembly platform shown in fig. 4.
In some embodiments, the assembly platform further includes a hall sensor 400 and a controller 500, the hall sensor 400 is disposed on the base plate 101 and located between each adjacent two of the first electromagnetic members 200, the hall sensor 400 sends a first electrical signal to the controller 500 when sensing the position of the light bar 2, and the controller 500 is configured to control the first electromagnetic member 200 and the second electromagnetic member 300 at corresponding positions to be energized according to the first electrical signal.
As shown in fig. 5 and 6, the polarity of the first permanent magnet 23 of the light bar 2 facing the bottom plate 101 is N pole, and the polarity of the first permanent magnet facing away from the assembly platform is S pole. The controller 500 may control the current direction and magnitude of the coil wound on the electromagnet of the first electromagnet 200 to control the magnetic pole of the first electromagnet 200 and the magnitude of the electromagnetic force. For example, the polarity of the first electromagnetic member 200 facing the first permanent magnetic member 23 is N, and according to the principle of mutual exclusion and opposite attraction of the magnets, a repulsive force is generated between the first electromagnetic member 200 and the first permanent magnetic member 23, and the repulsive force is greater than the gravity of the light bar 2.
As shown in fig. 5 and 7, the polarity of the first permanent magnet 23 of the light bar 2 facing the side plate 102 is N, and the controller 500 can control the current direction and magnitude of the coil wound on the electromagnet of the second electromagnetic member 300 to control the magnetic pole and magnitude of the electromagnetic force of the second electromagnetic member 300. For example, one of the two adjacent second electromagnetic members 300 has a polarity N toward the first permanent magnetic member 23, and the other has a polarity S toward the first permanent magnetic member 23, and the plurality of second electromagnetic members 300 generate electromagnetic force moving in the row direction Y with the first permanent magnetic member 23 of the light bar 2 according to the principle of mutual exclusion and opposite attraction of the magnetic poles, so as to drive the light bar 2 to move to the preset position of the lampshade 10.
Further, the hall sensor 400 is located between every two adjacent first electromagnetic members 200, and can automatically detect the coordinate position of the light bar 2, meanwhile, each pair of second electromagnetic members 300 is disposed corresponding to one row of first electromagnetic members 200, the hall sensor 400 sends a first electrical signal to the controller 500 when sensing the position of the light bar 2, and the controller 500 can control the first electromagnetic members 200 and the second electromagnetic members 300 at corresponding positions to be electrified according to the first electrical signal, so that the plurality of first electromagnetic members 200 and the plurality of second electromagnetic members 300 can be controlled to generate continuous electromagnetic force in the column direction Y, and the position of the light bar 2 can be precisely controlled.
Further, a driving circuit layer is further disposed on the bottom plate 101, and the first electromagnetic member 200, the second electromagnetic member 300, the controller 500 and the hall sensor 400 are electrically connected to the driving circuit layer, respectively. The core control circuit of the driving circuit layer is a single chip microcomputer, and can control the on-off state and the current of the first electromagnetic member 200 and the second electromagnetic member 300, and the signal transmission of the Hall sensor 400.
Optionally, the controller 500 is disposed on the side plate 102, more specifically, the controller 500 is disposed on the side plate 102 not provided with the second electromagnetic member 300, and the side plate 102 is disposed opposite to the opening and away from the side of the back plate 1, so as not to affect the movement of the light bar 2.
Fig. 8 is a block flow diagram of an assembly method of a light bar according to an embodiment of the present application.
As shown in fig. 8, the embodiment of the application further provides a method for assembling a light bar, which is applied to the assembly platform of the light bar as described above, and the method for assembling the light bar comprises the following steps S1 to S3.
Step S1: the back plate 1 is placed on the frame 100 of the assembly platform. The lamp housing 10 of the back plate 1 faces the opening side of the frame 100.
Step S2: the light bar 2 is placed on the bottom plate 101 of the frame 100. The lamp strip 2 can be placed on the bottom plate 101 at any angle, and the position or angle of the lamp strip 2 does not need to be manually adjusted, so that the working efficiency is improved.
Step S3: the first electromagnetic members 200 and the second electromagnetic members 300 are controlled to be electrified, repulsive force is generated between the first electromagnetic members 200 and the first permanent magnetic members 23 of the light bar 2, so that the light bar 2 is suspended at a preset height, and magnetic attraction force and repulsive force which are alternately changed in sequence are generated between the second electromagnetic members 300 and the first permanent magnetic members 23, so that the light bar 2 is driven to move to the lampshade 10 of the backboard 1.
As described above, after the first electromagnetic members 200 and the second electromagnetic members 300 are energized, a repulsive force can be generated between the first electromagnetic members 200 and the first permanent magnetic members 23 to suspend the light bar 2 at a predetermined height, and meanwhile, magnetic attraction and repulsive force can be generated between the second electromagnetic members 300 and the first permanent magnetic members 23 in turn and alternately changed to drive the light bar 2 to move to the lampshade 10 of the back plate 1. Because no manual assembly is needed, the lamp strip 2 can be moved to the preset position of the lamp shade 10 only by electromagnetic force, so that the accurate alignment of the lamp strip 2 is realized, the influence of the length of the lamp shade 10 of the backboard 1 is avoided, and the position accuracy and the assembly efficiency of the lamp strip 2 are greatly improved.
Further, the assembly platform further includes a hall sensor 400 and a controller 500, the hall sensor 400 is disposed on the base plate 101 and located between every two adjacent first electromagnetic members 200, and controlling the plurality of first electromagnetic members 200 and the plurality of pairs of second electromagnetic members 300 to be energized includes:
The hall sensor 400 transmits a first electric signal to the controller 500 when sensing the position of the light bar 2, and the controller 500 controls the first and second electromagnetic members 200 and 300 at the corresponding positions to be energized according to the first electric signal.
As described above, the hall sensor 400 is located between every two adjacent first electromagnetic members 200, and can automatically detect the coordinate position of the light bar 2, and meanwhile, each pair of second electromagnetic members 300 is disposed corresponding to one row of first electromagnetic members 200, and when the hall sensor 400 senses the position of the light bar 2, it sends a first electrical signal to the controller 500, and the controller 500 can control the first electromagnetic members 200 and the second electromagnetic members 300 at corresponding positions to be electrified according to the first electrical signal, so as to control the plurality of first electromagnetic members 200 and the plurality of second electromagnetic members 300 to generate continuous electromagnetic force in the column direction Y, and precisely control the position of the light bar 2.
Further, the lamp housing 10 of the back plate 1 is provided with a plurality of second permanent magnetic pieces 11, the second permanent magnetic pieces 11 can generate magnetic attraction force with the first permanent magnetic pieces 23 of the light bar 2, and after the light bar 2 moves to the lamp housing 10 of the back plate 1, the assembling method further comprises:
Step S4: the first permanent magnet piece 23 and the second permanent magnet piece 11 of the light bar 2 are adsorbed together;
step S5: controlling the plurality of first solenoid members 200 and the plurality of pairs of second solenoid members 300 to be powered off;
Step S6: the back plate 1 and the light bar 2 are removed.
In addition, the embodiment of the application also provides a display device which comprises the backlight module.
In one example, the display device is a liquid crystal display module, and includes a liquid crystal display panel and a backlight module disposed on a backlight side of the liquid crystal display panel, where the liquid crystal display panel does not emit light, and the backlight module needs to provide a light source with enough brightness and uniform distribution to enable the liquid crystal display panel to display images normally. The backlight module is used for providing a light source for the liquid crystal display panel.
The liquid crystal display panel comprises an array substrate, a color film substrate and a liquid crystal layer, wherein the array substrate and the color film substrate are oppositely arranged, the liquid crystal layer is arranged between the array substrate and the color film substrate, the liquid crystal layer comprises a plurality of liquid crystal molecules, and the liquid crystal molecules are generally rod-shaped, can flow like liquid and have certain crystal characteristics. When the liquid crystal molecules are in an electric field, the alignment direction thereof is changed according to the change of the electric field.
Further, the display device further comprises an upper polaroid positioned on the light emitting side of the liquid crystal display panel and a lower polaroid positioned on the backlight side of the liquid crystal display panel. The lower polarizer and the upper polarizer may polarize incident light of the liquid crystal display panel to allow light vibrating only in one direction to be transmitted.
It can be appreciated that the display device provided by the embodiments of the present application can be widely applied to, for example, a TN (TWISTED NEMATIC ) display panel, an IPS (In-PLANE SWITCHING ) display panel, a VA (VERTICAL ALIGNMENT, vertically aligned) display panel, an MVA (Multi-Domain VERTICAL ALIGNMENT, multi-quadrant vertically aligned) display panel, where the display panel is used In cooperation with the backlight module provided by the embodiments of the present application, and will not be described again.
It should be readily understood that the terms "on … …", "above … …" and "above … …" in this disclosure should be interpreted in the broadest sense so that "on … …" means not only "directly on something" but also includes "on something" with intermediate features or layers therebetween, and "above … …" or "above … …" includes not only the meaning "on something" or "above" but also the meaning "above something" or "above" without intermediate features or layers therebetween (i.e., directly on something).
The term "layer" as used herein may refer to a portion of material that includes regions having a certain thickness. The layer may extend over the entire underlying or overlying structure, or may have a range that is less than the range of the underlying or overlying structure. Further, the layer may be a region of a continuous structure, either homogenous or non-homogenous, having a thickness less than the thickness of the continuous structure. For example, the layer may be located between the top and bottom surfaces of the continuous structure or between any pair of lateral planes at the top and bottom surfaces. The layers may extend laterally, vertically and/or along a tapered surface.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.