Patent Publication Number: US-2022229333-A1

Title: Backlight modules, display panels and display apparatuses

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure claims a priority to Chinese patent application No. 202110063127.8 filed on Jan. 18, 2021 and entitled “BACKLIGHT MODULES, DISPLAY PANELS AND DISPLAY APPARATUSES”, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technology, and in particular to a backlight module, a display panel and a display apparatus. 
     BACKGROUND 
     With the development of display technology, display apparatuses have been used more and more commonly. In order to prevent leakage of information displayed on a display apparatus when a user uses the display apparatus in public places, a display apparatus with a privacy function has emerged. 
     SUMMARY 
     According to a first aspect of embodiments of the present disclosure, there is provided a backlight module, including: 
     a flexible light board, provided with a plurality of light-emitting elements arranged at intervals, and provided with a first wire at an edge thereof; 
     a back cover including a base plate, the flexible light board being provided on the base plate, and the base plate being provided with a second wire located on a same side as the first wire; and 
     a controller configured to control a direction of an electric current flowing through the first wire and a direction of an electric current flowing through the second wire, to generate an attractive force or a repulsive force between the first wire and the second wire. 
     In an embodiment, in the case that the repulsive force is generated between the first wire and the second wire, the edge of the flexible light board provided with the first wire is bent away from the base plate, such that the flexible light board changes from a flat state to a bent state; and in the case that the attractive force is generated between the first wire and the second wire, the edge of the flexible light board in the bent state moves close to the base plate, such that the flexible light board returns to the flat state. 
     In an embodiment, the first wire is substantially parallel to the second wire. 
     In an embodiment, the first wire and the second wire are opposite to each other in a direction from the flexible light board to the base plate. 
     In an embodiment, the first wire is located on a side of the flexible light board facing the base plate, and the second wire is located on a side of the base plate facing the flexible light board; and the backlight module further includes an insulating layer covering the first wire or the second wire. 
     In an embodiment, a central area of the flexible light board is fixedly connected with the base plate. 
     In an embodiment, the flexible light board includes a plurality of edges, and the first wire is provided at each of the plurality of edges. 
     In an embodiment, the first wire is provided at each of two adjacent edges of the flexible light board, and a cut-out is provided at a corner area of the flexible light board adjacent to the first wire provided at each of the two adjacent edges. 
     In an embodiment, the controller controls the direction of the electric current flowing through the first wire to remain unchanged, and controls the direction of the electric current flowing through the second wire to change, so as to control switching of the attractive force and the repulsive force between the first wire and the second wire; or the controller controls the direction of the electric current flowing through the second wire to remain unchanged, and controls the direction of the electric current flowing through the first wire to change, so as to control the switching of the attractive force and the repulsive force between the first wire and the second wire. 
     According to a second aspect of embodiments of the present disclosure, there is provided a display panel including a liquid crystal display module and the backlight module as described above, where the liquid crystal display module is located on a side of the backlight module away from the base plate. 
     According to a third aspect of embodiments of the present disclosure, there is provided a display apparatus including the display panel as described above. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic structural diagram illustrating a backlight module according to an exemplary embodiment of the present disclosure in a state. 
         FIG. 2  is a schematic structural diagram illustrating a backlight module according to an exemplary embodiment of the present disclosure in another state. 
         FIG. 3  is a schematic diagram illustrating generation of an attractive force between a first wire and a second wire according to an exemplary embodiment of the present disclosure. 
         FIG. 4  is a schematic diagram illustrating generation of a repulsive force between a first wire and a second wire according to an exemplary embodiment of the present disclosure. 
         FIG. 5  is a plan view illustrating a flexible light board according to an exemplary embodiment of the present disclosure. 
         FIG. 6  is a schematic structural diagram illustrating a display panel according to an exemplary embodiment of the present disclosure in a sharing state. 
         FIG. 7  is a schematic structural diagram illustrating a display panel according to an exemplary embodiment of the present disclosure in a privacy state. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments will be described in detail herein, and examples thereof are illustrated in the drawings. When the following description refers to the drawings, the same numbers in different drawings indicate the same or similar elements, unless otherwise indicated. Implementations described in the following exemplary embodiments do not represent all implementations in accordance with the present disclosure. Rather, they are merely examples of apparatuses in accordance with some aspects of the present disclosure as detailed in the appended claims. 
     Terms used in the present disclosure are only for the purpose of describing specific embodiments, and are not intended to limit the present disclosure. Singular forms of “a”, “said” and “the” used in the present disclosure and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the term “and/or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items. 
     It should be understood that though terms “first”, “second”, “third”, etc. may be used in the present disclosure to describe various information, such information should not be limited by these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word “if” as used herein may be interpreted as “when”, “upon” or “in response to determining”. 
     An existing display apparatus may realize a privacy function generally through a built-in or external privacy film. However, the display apparatus with the privacy film has a narrow viewing angle and may not be switched to a display state with a wide viewing angle, resulting in a poor user experience when the display apparatus is shared by multiple people. 
     Embodiments of the present disclosure provide a backlight module, a display panel and a display apparatus. The backlight module, display panel and display apparatus according to the embodiments of the present disclosure will be described in detail below in conjunction with the drawings. Features in the following embodiments may complement each other or be combined with each other without conflict. 
     Embodiments of the present disclosure provide a backlight module. Referring to  FIGS. 1 and 2 , the backlight module  100  includes a flexible light board  10 , a back cover  20 , and a controller. 
     The back cover  20  includes a base plate  21 , and the flexible light board  10  is provided on the base plate  21 . The flexible light board  10  is provided with a plurality of light-emitting elements  11  arranged at intervals, and provided with a first wire  12  at an edge thereof. The base plate  21  is provided with a second wire  22  located on the same side as the first wire  12 . The controller is configured to control a direction of an electric current flowing through the first wire  12  and a direction of an electric current flowing through the second wire  22 , to generate an attractive force or a repulsive force between the first wire  12  and the second wire  22 . 
     In the case that the repulsive force is generated between the first wire  12  and the second wire  22 , the edge of the flexible light board  10  provided with the first wire  12  is bent away from the base plate  21 , such that the flexible light board  10  changes from a flat state as shown in  FIG. 1  to a bent state as shown in  FIG. 2 . In the case that the attractive force is generated between the first wire  12  and the second wire  22 , the edge of the flexible light board  10  in the bent state moves close to the base plate  21 , such that the flexible light board  10  returns to the flat state as shown in  FIG. 1  from the bent state as shown in  FIG. 2 . 
     When the edge of the flexible light board  10  provided with the first wire  12  is bent away from the base plate  21 , light emitted from the light-emitting elements  11  located at the edge of the flexible light board  10  converges towards the centre, a display panel including the backlight module  100  has a reduced viewing angle, and the display panel is in a privacy state. When the edge of the flexible light board  10  provided with the first wire  12  moves close to the base plate  21  and the flexible light board  10  becomes flat, light emitted from the light-emitting elements  11  located at the edge of the flexible light board  10  diverges to the edge, the display panel including the backlight module  100  has an increased viewing angle, and the display panel is in a sharing state. 
     In the backlight module according to the embodiments of the present disclosure, when the controller controls the direction of the current flowing through the first wire  12  and the direction of the current flowing through the second wire  22  to generate the repulsive force between the first wire  12  and the second wire  22 , the edge of the flexible light board  10  provided with the first wire  12  is bent away from the base plate  21 , and the display panel including the backlight module  100  is switched to the privacy state. When the controller controls the direction of the current flowing through the first wire  12  or the direction of the current flowing through the second wire  22  to generate the attractive force between the first wire  12  and the second wire  22 , the edge of the flexible light board  10  provided with the first wire  12  moves close to the base plate  21 , and the display panel including the backlight module  100  is switched to the sharing state. The backlight module may enable the display panel where it is located to switch between the privacy state and the sharing state, which can better meet the needs of users and improve the user experience. By providing the first wire and the second wire, and using the controller to control the direction of the current flowing through the first wire and the direction of the current flowing through the second wire, the display panel may be switched between the privacy state and the sharing state. Thus, the backlight module has a simple structure, a small thickness, and low cost, and the backlight module is simple to control, can quickly switch between the privacy state and the sharing state of the display panel, and requires low power consumption. 
     During use of a display apparatus including the backlight module, when a user needs to switch from the sharing state to the privacy state, he/she may send a corresponding control command to the display apparatus through a button or a touch screen of the display panel. The controller controls the direction of the current flowing through the first wire and the direction of the current flowing through the second wire based on the received control command, to generate the repulsive force between the first wire and the second wire, and then the edge of the flexible light board  10  where the first wire is located is bent away from the base plate  21 , under the action of the repulsive force. When a user needs to switch from the privacy state to the sharing state, he/she may send a corresponding control command to the display apparatus through a button or a touch screen of the display panel. The controller controls the direction of the current flowing through the first wire or the direction of the current flowing through the second wire based on the received control command, to generate the attractive force between the first wire and the second wire, and then the edge of the flexible light board  10  where the first wire is located moves toward the base plate  21 , under the action of the attractive force, and the flexible light board  10  may become flat. 
     Principle of generation of the attractive and repulsive forces between the first wire and the second wire will be described below. 
     When an electric current flows through the first wire, a magnetic field may be generated around the first wire. When an electric current flows through the second wire, a magnetic field may be generated around the second wire. The first wire is subjected to an Ampere&#39;s force in the magnetic field generated by the second wire. The second wire is subjected to an Ampere&#39;s force in the magnetic field generated by the first wire. 
     In an embodiment, referring to  FIG. 3 , when the controller controls the direction of the current I 1  flowing through the first wire  12  to be the same as the direction of the current I 2  flowing through the second wire  22 , a direction of a magnetic induction line B 1  of a magnetic field generated by the first wire  12  is the same as a direction of a magnetic induction line B 2  of a magnetic field generated by the second wire  22 . According to the left-hand rule, the first wire  12  is subjected to an Ampere&#39;s force F 1  in a direction from the first wire  12  towards the second wire  22 , and the second wire  22  is subjected to an Ampere&#39;s force F 2  in a direction from the second wire  22  towards the first wire  12 . That is, the attractive force is generated between the first wire  12  and the second wire  22 . The first wire  12  moves closer to the second wire  22  under the action of the Ampere&#39;s force F 1 , such that the edge of the flexible light board  10  changes from the bent state to the flat state. 
     Referring to  FIG. 4 , when the controller controls the direction of the current flowing through the first wire  12  to be opposite to the direction of the current I 2  flowing through the second wire  22 , a direction of a magnetic induction line B 1  of a magnetic field generated by the first wire  12  is opposite to a direction of a magnetic induction line B 2  of a magnetic field generated by the second wire  22 . According to the left-hand rule, the first wire  12  is subjected to an Ampere&#39;s force F 1  in a direction from the second wire  22  towards the first wire  12 , and the second wire  22  is subjected to an Ampere&#39;s force F 2  in a direction from the first wire  12  towards the second wire  22 . That is, the repulsive force is generated between the first wire  12  and the second wire  22 . The first wire  12  moves away from the second wire  22  under the action of the Ampere&#39;s force F 1 , such that the edge of the flexible light board  10  changes from the flat state to the bent state. 
     In the embodiments of the present disclosure, the first wire  12  and the second wire  22  may be made of a metal material with a good electrical conductivity, such as copper and silver. 
     In an embodiment, the backlight module  100  may further include a circuit board  30 , and the controller may be a chip integrated on the circuit board  30 . The circuit board  30  may be provided with a power supply circuit, which supplies power to the first wire  12 , the second wire  22  and the light-emitting elements  11 . The circuit board  30  may also be provided with a switch circuit, which is connected between the power supply circuit and the first wire  12  or the second wire  22 . The controller may control the switch circuit to change the direction of the current flowing through the first wire  12  or the second wire  22 . The circuit board  30  may be a PCB (Printed Circuit Board). The circuit board  30  may be provided on a side of the back cover  20 , that is, on a bezel area of the display panel where the backlight module  100  is located, or the circuit board  30  may be provided on a side of the base plate  21  away from the flexible light board  10 . 
     In an embodiment, the controller controls the direction of the current flowing through the first wire  12  to remain unchanged, and controls the direction of the current flowing through the second wire  22  to change, so as to control switching of the attractive force and the repulsive force between the first wire  12  and the second wire  22 . Alternatively, the controller controls the direction of the current flowing through the second wire  22  to remain unchanged, and controls the direction of the current flowing through the first wire  12  to change, so as to control the switching of the attractive force and the repulsive force between the first wire  12  and the second wire  22 . In this way, by controlling the direction of the current flowing through one of the first wire  12  and the second wire  22 , the flexible light board  10  may be switched between the bent state and the flat state. 
     In an embodiment, the flexible light board  10  may include a flexible circuit board  13 , and the light-emitting elements  11  may be disposed on the flexible circuit board  13 . The light-emitting elements  11  may be electrically connected with the circuit board  30  through wiring in the flexible circuit board  13 . 
     In an embodiment, the wiring in the flexible circuit board  13  and the first wire  12  may be formed at the same time. A preparation process of the flexible circuit board may include: providing a first insulating film layer; forming the first wire  12  and the wiring on the first insulating film layer; forming a second insulating film layer covering the first wire  12  and the wiring; and etching the second insulating film layer to expose the first wire  12 . 
     In an embodiment, the first wire  12  of the flexible light board  10  may be substantially parallel to the second wire  22  located on the same side. The first wire  12  being substantially parallel to the second wire  22  may include the first wire  12  being parallel to the second wire  22 , and there being a small angle between the first wire  12  and the second wire  22 , for example, the angle between the first wire  12  and the second wire  22  is less than 10°. In this way, the attractive and repulsive forces between the first wire  12  and the second wire  22  located on the same side may be made large, which helps to increase a speed of switching between the bent state and the flat state of the edge of the flexible light board  10 , thereby shortening time required to switch between the privacy state and the sharing state of the display panel and improving the user experience. 
     In an embodiment, when the flexible light board  10  is in the flat state, the first wire  12  of the flexible light board  10  and the second wire  22  located on the same side may be opposite to each other in a first direction. The first direction refers to a direction from the flexible light board  10  to the base plate  21 . The first wire  12  and the second wire  22  being opposite to each other in the first direction means that a position of the first wire  12  in the first direction roughly corresponds to a position of the second wire  22  in the first direction. In this way, there may be a small distance between the first wire  12  and the second wire  22 , the first wire  12  and the second wire  22  may be subjected to high magnetic field strength, and the attractive force or the repulsive force between the first wire  12  and the second wire  22  may be relatively large, which helps to increase a speed of switching between the bent state and the flat state of the edge of the flexible light board  10 , thereby shortening time required to switch between the privacy state and the sharing state of the display panel and improving the user experience. 
     In an embodiment, the first wire  12  may be located on a side of the flexible light board  10  facing the base plate  21 , and the second wire  22  may be located on a side of the base plate  21  facing the flexible light board  10 . The backlight module  100  may further include an insulating layer (not shown) covering the first wire  12  or the second wire  22 . In this way, the first wire  12  and the second wire  22  may have a small distance therebetween, and the attractive force or the repulsive force between the first wire  12  and the second wire  22  may be relatively large, which helps to increase a speed of switching between the bent state and the flat state of the edge of the flexible light board  10 , thereby shortening time required to switch between the privacy state and the sharing state of the display panel and improving the user experience. The insulating layer is provided to prevent the first wire  12  from directly contacting with the second wire  22  to affect the switch between the bent state and the flat state of the edge of the flexible light board  10 . The insulating layer has a relatively thin thickness, which basically does not affect the strength of the magnetic field generated by the first wire  12  and the second wire  22 . 
     In an embodiment, a central area of the flexible light board  10  may be fixedly connected with the base plate  21 . This may prevent the flexible light board  10  from shifting during the bending of the edge of the flexible light board  10  to affect a display effect of the display panel where the backlight module  100  is located. The central area of the flexible light board  10  may be fixedly connected with the base plate  21  through an adhesive or a connecting member. 
     In an embodiment, referring to  FIG. 5 , the flexible light board  10  may have a rectangular shape. The flexible light board  10  may include a plurality of edges, and the first wire  12  may be provided at each of the plurality of edges. In this way, each edge of the flexible light board  10  may be bent, that is, each edge of the display panel where the backlight module  100  is located may be switched to the privacy state. The user may control any edge of the display panel to switch to the privacy state as needed, which helps to better meet the needs of the user and improve the user experience. The embodiment shown in  FIG. 5  only takes the flexible light board having the rectangular shape as an example for illustration. In other embodiments, the flexible light board  10  may have an irregular shape, a circular shape, an oval shapes, etc. 
     In an embodiment, the first wire  12  may be provided at each of two adjacent edges of the flexible light board  10 , and a cut-out  101  may be provided at a corner area of the flexible light board  10  adjacent to the first wire  12  provided at each of the two adjacent edges. When the two adjacent edges of the flexible light board  10  are bent away from the base plate  21  at the same time, the cut-out  101  is provided to prevent wrinkles from occurring in the corner area of the flexible light board  10 , such that the adjacent edges of the flexible light board  10  may be smoothly bent away from the base plate  21 . The embodiment as shown only takes the cut-out  101  having a rectangular shape as an example for illustration. In practice, the cut-out  101  may have any shape, as long as it may prevent wrinkles from occurring in the corner area when the adjacent edges of the flexible light board  10  are bent away from the base plate  21  at the same time. 
     In an embodiment, referring back to  FIGS. 1 and 2 , the backlight module  100  may further include an optical film  40 , which is located on a side of the flexible light board  10  away from the base plate  21 . The optical film  40  may include a diffusion film, a brightness enhancement film, a light homogenizer, etc. There is a gap between the flexible light board  10  and the optical film  40 . The gap allows the edge of the flexible light board  10  to be bent away from the base plate  21  without touching the optical film  40 . The gap also allows light emitted from the flexible light board  10  to be mixed before it is incident on the optical film  40  to improve uniformity of light emitted from the backlight module  100 . 
     In an embodiment, the light-emitting element  11  may be a mini LED. In this way, a larger number of light-emitting elements  11  may be provided on the flexible light board  10 . A plurality of light-emitting elements  11  may be arranged on the flexible light board  10  at uniform intervals, which is conducive to more uniform distribution of the light-emitting elements  11 , thereby improving brightness uniformity of the display panel where the backlight module is located. 
     In an embodiment, an electrode fixing structure may be provided on the base plate  21  of the back cover  20 , and both ends of the second wire  22  may be fixed on the base plate  21  and electrically connected with the circuit board  30  through the electrode fixing structure. The base plate  21  may be insulated from the second wire  22 , such that the base plate  21  may not affect the direction of the current in the second wire  22 . A groove may be provided in the base plate  21 , and the second wire  22  may be accommodated in the groove of the base plate  21 , such that when the flexible light board  10  is in the flat state, the bottom of the flexible light board  10  may be flush everywhere, avoiding bulging of an area of the flexible light board  10  corresponding to the second wire  22  in the case where the second wire  22  is provided directly on the base plate  21  to affect uniformity of the light emitted from the light-emitting elements. 
     In an embodiment, the back cover  20  may further include an enclosure  23  connected with the base plate  21 . The enclosure  23  and the base plate  21  may form an accommodating space  201  in which the flexible light board  10  and the optical film  40  are accommodated. The base plate  21  and the enclosure  23  may be integrally formed. 
     In an embodiment, a side of the enclosure  23  away from the base plate  21  may extend inwardly to form a supporting portion  231  for installing a liquid crystal display module of the display panel where the backlight module is located. 
     Embodiments of the present disclosure further provide a display panel. Referring to  FIGS. 6 and 7 , the display panel  200  includes a liquid crystal display module  210  and the backlight module  100  according to any of the embodiments described above. The liquid crystal display module  210  is located on a side of the backlight module  100  away from the base plate  21 . 
     The liquid crystal display module  210  may be installed on the supporting portion  231 . 
     Embodiments of the present disclosure further provide a display apparatus including the display panel according to any of the embodiments described above. 
     The display apparatus may further include a housing in which the display panel is embedded. 
     The display apparatus according to the embodiments of the present disclosure may include, for example, a mobile phone, a tablet computer, a television, a notebook computer, a vehicle-mounted device, and any other device with a display function. 
     It should be pointed out that in the drawings, sizes of layers and areas may be exaggerated for clarity of illustration. It should be understood that when an element or layer is referred to as being “on” another element or layer, it can be directly on the other element or layer, or an intervening element or layer may be present. In addition, it should be understood that when an element or layer is referred to as being “under” another element or layer, it can be directly under the other element or layer, or there may be more than one intervening layer or element. It should also be understood that when a layer or element is referred to as being “between” two layers or two elements, it can be the only layer between the two layers or the two elements, or there may be more than one intervening layer or element. Similar reference numerals indicate similar elements throughout. 
     Those skilled in the art will easily conceive of other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. The present disclosure is intended to cover any variations, uses or adaptive changes of the present disclosure. These variations, uses or adaptive changes follow the general principles of the present disclosure and include common knowledge or conventional technical means in the art that are not disclosed by the present disclosure. The specification and the embodiments are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are pointed out by the following claims. 
     It should be understood that the present disclosure is not limited to the precise structure that has been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is only limited by the appended claims.