Patent Publication Number: US-2023144891-A1

Title: Backlight module, manufacturing method thereof, and liquid crystal display device

Description:
FIELD OF INVENTION 
     The present application relates to the field of display technologies, and in particular to a backlight module, a manufacturing method thereof, and a liquid crystal display device. 
     BACKGROUND OF INVENTION 
     As liquid crystal display devices gradually develop toward an ultra-narrow frame, it is required that a backlight module providing backlight for liquid crystal display panels occupies as little frame space as possible. Traditional backlight module is mainly composed of light-emitting diode (LED) lamp beads. According to different installation positions, the backlight module can be classified into two types of side-lit backlight module and direct-lit backlight module. The side-lit backlight module is disposed on a side of the liquid crystal display panels, so that the liquid crystal display devices with the side-lit backlight module cannot achieve ultra-narrow frame. The direct-lit backlight module is disposed on a backside of the liquid crystal display panels, so that the liquid crystal display devices with a direct-lit backlight module can realize the ultra-narrow frame, but this will increase an overall thickness of the liquid crystal display devices. 
     A new type of backlight module developed nowadays is a sub-millimeter light-emitting diode (mini-LED) backlight module. The mini-LED backlight module uses a smaller mini-LED chip to replace traditional LED lamp beads, the mini-LED backlight module is disposed on the backside of the liquid crystal display panel, which not only enables the liquid crystal display devices with the mini-LED backlight module to realize the ultra-narrow frame, but also reduces the overall thickness of the liquid crystal display devices. However, a light-outputting efficiency of the conventional mini-LED backlight module is lower. 
     SUMMARY OF INVENTION 
     Technical Problem 
     The present application provides a backlight module, a manufacturing method thereof, and a liquid crystal display device, so as to solve the problem of lower light-outputting efficiency of the conventional mini-LED backlight module. 
     Technical Solutions 
     In a first aspect, the present application provides a backlight module, which includes a substrate, a light-emitting chip and a reflective layer disposed on the substrate. Wherein the reflective layer includes a hollowed-out region, the light-emitting chip is electrically connected to the substrate in the hollowed-out region, and a projection of an edge of the hollowed-out region on the substrate is at least partially positioned within a coverage of a projection of the light-emitting chip on the substrate. 
     In some embodiments, the projection of the edge of the hollowed-out region on the substrate is positioned within the projection of the light-emitting chip on the substrate, and a distance between the edge of the hollowed-out region and the projection of the light-emitting chip on the substrate is greater than a first predetermined value. 
     In some embodiments, a surface of the substrate is disposed with a pad layer, the light-emitting chip includes a chip body and a pin layer electrically connected to the chip body, and the pin layer is electrically connected to the pad layer through a conductive layer in the hollowed-out region. 
     In some embodiments, the pad layer includes a first pad and a second pad, the pin layer includes a first pin and a second pin, the conductive layer includes a first conductor and a second conductor, the hollowed-out region includes a first hollowed-out sub-region and a second hollowed-out sub-region, wherein the first pin in the first hollowed-out sub-region is electrically connected to the first pad through the first conductor, and the second pin in the second hollowed-out sub-region is electrically connected to the second pad through the second conductor. 
     In some embodiments, a projection of the chip body on the substrate covers a part of a projection of the pad layer on the substrate, and the reflective layer is at least partially disposed on a surface of the pad layer. 
     In some embodiments, a projection of the chip body on the substrate entirely covers a projection of the pad layer on the substrate, and the reflective layer is at least partially disposed on a surface of the substrate. 
     In some embodiments, a distance between the reflective layer and the chip body in a direction perpendicular to the substrate is greater than a second predetermined value. 
     In some embodiments, a distance between a projection of any one of the conductive layer or the pin layer on the substrate and a projection of the edge of the hollowed-out region on the substrate is greater than a third predetermined value. 
     In some embodiments, a material of the reflective layer includes white oil. 
     In some embodiments, the conductive layer is made of a conductive glue. 
     In a second aspect, the present application provides a manufacturing method of a backlight module, including: 
     providing a substrate, and fabricating a reflective layer with a hollowed-out region on the substrate; and 
     electrically connecting a light-emitting chip to the substrate in the hollowed-out region, wherein a projection of an edge of the hollowed-out region on the substrate is at least partially positioned within a coverage of a projection of the light-emitting chip on the substrate. 
     In some embodiments, the projection of the edge of the hollowed-out region on the substrate is positioned within the projection of the light-emitting chip on the substrate, and a distance between the edge of the hollowed-out region and the projection of the light-emitting chip on the substrate is greater than a first predetermined value. 
     In a third aspect, the present application provides a liquid crystal display device, including a liquid crystal display panel and a backlight module; wherein the backlight module includes a substrate and a light-emitting chip and a reflective layer disposed on the substrate, the reflective layer includes a hollowed-out region, the light-emitting chip is electrically connected to the substrate in the hollowed-out region, and a projection of an edge of the hollowed-out region on the substrate is at least partially positioned within a coverage of a projection of the light-emitting chip on the substrate. 
     In some embodiments, the projection of the edge of the hollowed-out region on the substrate is positioned within the projection of the light-emitting chip on the substrate, and a distance between the edge of the hollowed-out region and the projection of the light-emitting chip on the substrate is greater than a first predetermined value. 
     In some embodiments, a surface of the substrate is disposed with a pad layer, the light-emitting chip includes a chip body and a pin layer electrically connected to the chip body, and the pin layer is electrically connected to the pad layer through a conductive layer in the hollowed-out region. 
     In some embodiments, the pad layer includes a first pad and a second pad, the pin layer includes a first pin and a second pin, the conductive layer includes a first conductor and a second conductor, and the hollowed-out region includes a first hollowed-out sub-region and a second hollowed-out sub-region, wherein the first pin in the first hollowed-out sub-region is electrically connected to the first pad through the first conductor, and the second pin in the second hollowed-out sub-region is electrically connected to the second pad through the second conductor. 
     In some embodiments, a projection of the chip body on the substrate covers a part of a projection of the pad layer on the substrate, and the reflective layer is at least partially disposed on a surface of the pad layer. 
     In some embodiments, a projection of the chip body on the substrate entirely covers a projection of the pad layer on the substrate, and the reflective layer is at least partially disposed on the surface of the substrate. 
     In some embodiments, a distance between the reflective layer and the chip body in a direction perpendicular to the substrate is greater than a second predetermined value. 
     In some embodiments, a distance between a projection of any one of the conductive layer or the pin layer on the substrate and a projection of an edge of the hollowed-out region on the substrate is greater than a third predetermined value. 
     Beneficial Effect 
     In the backlight module, the manufacturing method thereof, and the liquid crystal display device provided by the present application, the light originally irradiated by the light-emitting chip on the substrate, the first pad, or the second pad will irradiate to the reflective layer, and be reflected by the reflective layer and then emitted from the backlight module, thereby improving a luminous efficiency of the backlight module. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
         FIG.  1    is a schematic structural diagram of a backlight module provided by an embodiment of the present application. 
         FIG.  2    is a schematic partial top view of a first backlight module provided by an embodiment of the present application. 
         FIG.  3    is a cross-sectional view of the backlight module shown in  FIG.  2    along line I-I. 
         FIG.  4    is a schematic partial top view of a second backlight module provided by an embodiment of the present application. 
         FIG.  5    is a schematic partial top view of a third backlight module provided by an embodiment of the present application. 
         FIG.  6    is a cross-sectional view of the backlight module shown in  FIG.  5    along line III-III. 
         FIG.  7    is a schematic partial top view of a fourth backlight module provided by an embodiment of the present application. 
         FIG.  8    is a flowchart of a manufacturing method of a backlight module provided by an embodiment of the present application. 
         FIG.  9    is a schematic structural diagram of a liquid crystal display device provided by an embodiment of the present application. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     In order to make the purpose, technical solutions, and effects of the present application in a clearer manner, the following further describes the present application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application. 
       FIG.  1    is a schematic structural diagram of a backlight module provided by an embodiment of the present application,  FIG.  2    is a partial top view schematic diagram of a first backlight module provided by an embodiment of the present application, and  FIG.  3    is a schematic diagram of the backlight module shown in  FIG.  2    along line I-I. It should be noted that the backlight module in the embodiments of the present application is a sub-millimeter light-emitting diode (mini-LED) backlight module, which is referred to as a backlight module for ease of description. As shown in  FIG.  1   , the backlight module  1  includes a plurality of light-emitting regions  10 .  FIG.  2    only shows a single light-emitting region  10 . As shown in  FIG.  2    and  FIG.  3   , the light-emitting region  10  includes a substrate  101  and a light-emitting chip and a reflective layer  103 . Wherein, the light-emitting chip is a chip capable of emitting light, and the light-emitting chip in the embodiments of the present application is a mini-LED chip. The reflective layer  103  is a functional layer that reflects light. The reflective layer  103  is disposed on a light path of the light emitted from the light-emitting chip to the substrate  101 . The reflective layer  103  is used to reflect the light irradiated by the light-emitting chip to the reflective layer  103  and then emit it from the backlight module. The reflective layer  103  can be white oil. 
     The reflective layer  103  includes a hollowed-out region. A projection of the reflective layer  103  on the substrate  101  includes an outer edge  1031  and an inner edge  1032 . A projection of an edge of the hollowed-out region on the substrate  101  is the aforementioned inner edge  1032 . The light-emitting chip is electrically connected to the substrate  101  in the hollowed-out region. Wherein, the outer edge  1031  surrounds a projection of the light-emitting chip on the substrate  101  and is spaced from the projection of the light-emitting chip on the substrate  101 , and the inner edge  1032  is at least partially positioned within a coverage of the projection of the light-emitting chip on the substrate  101 . 
     Specifically, the projection of the light-emitting chip on the substrate  101  is rectangular, the outer edge  1031  encloses a closed region and the closed region is rectangular, and the outer edge  1031  is spaced from the projection of the light-emitting chip on the substrate  101 . It should be noted that the projection of the light-emitting chip on the substrate  101  can also be square, circular, or other shapes, which are mainly determined according to a shape of the light-emitting chip. A shape of the closed region enclosed by the outer edge  1031  can also be square, circular, or other shapes, which can be flexibly adjusted by those skilled in the art according to actual application requirements. 
     The inner edge  1032  encloses a closed region and the closed region is rectangular. The inner edge  1032  is positioned within the projection of the light-emitting chip on the substrate  101 , and a distance between the inner edge  1032  and the projection of the light-emitting chip on the substrate  101  is greater than a first predetermined value. Wherein, the first predetermined value can be flexibly adjusted by those skilled in the art according to actual application requirements. It should be noted that the closed region enclosed by the inner edge  1032  can also be square, circular, or other shapes, and those skilled in the art can flexibly adjust according to actual application requirements. The closed region enclosed by the inner edge  1032  can also coincide with the projection of the light-emitting chip on the substrate  101 , that is, there is no distance between the inner edge  1032  and the projection of the light-emitting chip on the substrate  101 . 
     Since the outer edge  1031  of the reflective layer  103  projected on the substrate  101  surrounds the projection of the light-emitting chip on the substrate  101  and is spaced from the projection of the light-emitting chip on the substrate  101 , the inner edge  1032  of the reflective layer  103  projected on the substrate  101  is at least partially positioned within the coverage of the projection of the light-emitting chip on the substrate  101 . Therefore, the light originally irradiated by the light-emitting chip on the substrate  101 , a first pad  1021 , or a second pad  1022  will irradiate to the reflective layer  103 , and be reflected by the reflective layer  103  and then emitted from the backlight module, thereby improving a luminous efficiency of the backlight module. 
     As shown in  FIG.  2    and  FIG.  3   , a surface of the substrate is disposed with a pad layer. The light-emitting chip includes a chip body and a pin layer electrically connected to the chip body. The pin layer is electrically connected to the pad layer through a conductive layer in the hollowed-out region. 
     Specifically, the pad layer includes the first pad  1021  and the second pad  1022 . The first pad  1021  and the second pad  1022  are spaced apart on the substrate  101 , and both the first pad  1021  and the second pad  1022  are electrically connected to an external control circuit. The light-emitting chip includes the chip body  106  and the pin layer electrically connected to the chip body  106 . The chip body  106  is mainly composed of a light-emitting circuit for emitting light. The pin layer includes a first pin  1051  and a second pin  1052  disposed at intervals. The first pin  1051  and the second pin  1052  are connecting lines from the light-emitting circuit to a peripheral circuit. The conductive layer includes a first conductor  1041  and a second conductor. The first conductor  1041  and the second conductor can be conductive glue or solder paste. The conductive glue is preferably anisotropic conductive film (ACF). 
     The pin layer is electrically connected to the pad layer through the conductive layer in the hollowed-out region. It should be noted that the hollowed-out region is an opening structure in the reflective layer  103 , or can be a plurality of spaced opening structures in the reflective layer  103 . The hollowed-out region in the backlight module shown in  FIG.  2    and  FIG.  3    is an opening structure in the reflective layer  103 . Specifically, the first pin  1051  is electrically connected to the first pad  1021  in the hollowed-out region through the first conductor  1041 , and the second pin  1052  is electrically connected to the second pad  1022  in the hollowed-out region through the second conductor. In this way, the light-emitting chip is electrically connected with the external control circuit, and the light-emitting chip is controlled by the external control circuit. 
     As shown in  FIG.  2    and  FIG.  3   , a projection of the chip body  106  on the substrate  101  covers a part of a projection of the pad layer on the substrate  101 , and the reflective layer  103  is at least partially disposed on a surface of the pad layer. 
     Specifically, the projection of the chip body  106  on the substrate  101  in the backlight module shown in  FIG.  2    and  FIG.  3    covers a part of a projection of the first pad  1021  on the substrate  101  and a part of a projection of the second pad  1022  on the substrate  101 . The reflective layer  103  is partially disposed on surfaces of the first pad  1021  and the second pad  1022 , and another part of the reflective layer  103  is disposed on the surface of the substrate  101 . It should be noted that the projection of the chip body  106  on the substrate  101  entirely covers the projection of the pad layer on the substrate  101 , and the reflective layer  103  is at least partially disposed on the surface of the substrate. For example, the reflective layer  103  is partially disposed on the surface of the substrate  101 , and another part of the reflective layer  103  is disposed on the surfaces of the first pad  1021  and the second pad  1022 . In another example, entire reflective layer  103  is disposed on the surface of the substrate  101 , that is, the reflective layer  103 , the first pad  1021 , and the second pad  1022  are disposed on a same layer. 
     As shown in  FIG.  2    and  FIG.  3   , a distance between the reflective layer  103  and the chip body  106  in a direction perpendicular to the substrate  101  is greater than a second predetermined value. 
     Specifically, in a manufacturing process of the backlight module, the reflective layer  103  needs to be fabricated first, and then the light-emitting chip is respectively soldered to the first pad  1021  and the second pad  1022  in the hollowed-out region of the reflective layer  103 , that is, a die-bonding. Therefore, there is the distance between the reflective layer  103  and the chip body  106 , so as to prevent the light-emitting chip from an occurrence of virtual soldering during a die-bonding operation, and improve a yield of the backlight module. 
     It should be noted that the second predetermined value can be set by combined a manufacturing accuracy of the reflective layer and an accuracy of the die-bonding, where the manufacturing accuracy of the reflective layer refers to a deviation between a predetermined size of the reflective layer and an actual size of the reflective layer made according to the predetermined size, and the accuracy of the die-bonding refers to a deviation between a predetermined position of the light-emitting chip during die-bonding and an actual position of the light-emitting chip after die-bonding according to the predetermined position. In general, the reflective layer  103  is white oil. A range of manufacturing accuracy is 50-100 microns, and a range of die-bonding accuracy is 25-50 microns. Therefore, the second predetermined value can be selected as 150 microns to ensure that the actual backlight module will not cause the occurrence of virtual soldering of the light-emitting chip due to an influence of the manufacturing accuracy of the reflective layer and the accuracy of die-bonding. Of course, this value is only an example of the second predetermined value, and does not constitute a limitation thereof, and the second predetermined value can be flexibly adjusted by those skilled in the art according to actual needs. 
     As shown in  FIG.  2    and  FIG.  3   , a distance between a projection of any one of the conductive layer or the pin layer on the substrate  101  and a projection of the edge of the hollowed-out region on the substrate  101  is greater than a third predetermined value. 
     Specifically, the reflective layer  103  is usually white oil, and the white oil is an insulator. If the white oil contacts any of the first conductor  1041 , the second conductor, the first pin  1051 , or the second pin  1052 , it will affect a conductivity of the first conductor  1041 , the second conductor, the first pin  1051 , or the second pin  1052  that is in contact with the white oil, thereby reducing a luminous brightness of the light-emitting chip. Therefore, all the first conductor  1041 , the second conductor, the first pin  1051 , and the second pin  1052  are spaced from the reflective layer  103 , which can ensure that a brightness of the light-emitting chip is not affected. 
     It should be noted that the third predetermined value can be set by combining the manufacturing accuracy of the reflective layer and the accuracy of die-bonding. In general, the reflective layer  103  is white oil, the manufacturing accuracy of white oil is 50-100 microns, and the accuracy of die-bonding ranges from 25 microns to 50 microns, so the third predetermined value can be selected as 150 microns to ensure that the actual manufactured backlight module will not lead to the reflective layer to contact any of the first conductor  1041 , the second conductor, the first pin  1051 , or the second pin  1052  caused by the manufacturing accuracy of the reflective layer and the accuracy of die-bonding. Of course, this value is only an example of the third predetermined value, and does not constitute a limitation thereof, and the third predetermined value can be flexibly adjusted by those skilled in the art according to actual needs. 
     Hereinafter, other modified structures of the backlight module provided by the embodiments of the present application will be described. 
     It can be seen from the above embodiment that the hollowed-out region can also be a plurality of spaced opening structures in the reflective layer  103 . An embodiment of the present application takes two spaced opening structures in the reflective layer  103  as the hollowed-out region as an example for description. Wherein, the two opening structures of the hollowed-out region are respectively referred to as a first hollowed-out sub-region and a second hollowed-out sub-region. 
       FIG.  4    is a partial top view of a second backlight module provided by an embodiment of the present application. As shown in  FIG.  4   , a projection of a reflective layer  103  on the substrate  101  includes an outer edge  1031  and an inner edge  1032 , and the inner edge  1032  includes a first inner edge  10321  and a second inner edge  10322  spaced apart. A projection of the first hollowed-out sub-region on the substrate  101  is the first inner edge  10321 , and a projection of the second hollowed-out sub-region on the substrate  101  is the second inner edge  10322 . Wherein, the outer edge  1031  surrounds a projection of the light-emitting chip on the substrate  101 , and is spaced from the projection of the light-emitting chip on the substrate  101 . The first inner edge  10321  and the second inner edge  10322  are at least partially positioned within a coverage of the projection of the light-emitting chip on the substrate  101 . 
     Specifically, the projection of the light-emitting chip on the substrate  101  is rectangular, the outer edge  1031  encloses a closed region and the closed region is rectangular, and the outer edge  1031  is spaced from the projection of the light-emitting chip on the substrate  101 . It should be noted that the projection of the light-emitting chip on the substrate  101  can also be square, circular, or other shapes, which are mainly determined according to a shape of the light-emitting chip. A shape of the closed region enclosed by the outer edge  1031  can also be square, circular, or other shapes, which can be flexibly adjusted by those skilled in the art according to actual application requirements. 
     The first inner edge  10321  encloses a closed region and the closed region is rectangular. The first inner edge  10321  is positioned within the projection of the light-emitting chip on the substrate  101 , and a distance between the first inner edge  10321  and the projection of the light-emitting chip on the substrate  101  is greater than a first predetermined value. Wherein, the first predetermined value can be flexibly adjusted by those skilled in the art according to actual application requirements. It should be noted that the closed region enclosed by the first inner edge  10321  can also be square, circular, or other shapes, and those skilled in the art can flexibly adjust according to actual application requirements. The closed region enclosed by the first inner edge  10321  can also coincide with the projection of the light-emitting chip on the substrate  101 , that is, there is no distance between the first inner edge  10321  and the projection of the light-emitting chip on the substrate  101 . 
     The second inner edge  10322  encloses a closed region and the closed region is rectangular. The second inner edge  10322  is positioned within the projection of the light-emitting chip on the substrate  101 , and a distance between the second inner edge  10322  and the projection of the light-emitting chip on the substrate  101  is greater than the first predetermined value. Wherein, the first predetermined value can be flexibly adjusted by those skilled in the art according to actual application requirements. It should be noted that the closed region enclosed by the second inner edge  10322  can also be square, circular, or other shapes, and those skilled in the art can flexibly adjust according to actual application requirements. The closed region enclosed by the second inner edge  10322  can also coincide with the projection of the light-emitting chip on the substrate  101 , that is, there is no distance between the second inner edge  10322  and the projection of the light-emitting chip on the substrate  101 . 
     It should be noted that a cross-sectional view of the backlight module shown in  FIG.  4    along line II-II is shown in  FIG.  3   . Since the cross-sectional structure of the backlight module shown in  FIG.  3    has been described in detail in the above embodiment, it will not be repeated here. 
     It is understandable that compared with the light-emitting region  10  shown in  FIG.  2    and  FIG.  3   , the light-emitting region  10  shown in  FIG.  4    is further disposed with a reflective layer  103  between the first hollowed-out sub-region and the second hollowed-out sub-region. That is, an area of the reflective layer  103  is larger, so that the luminous efficiency of the backlight module can be further improved. 
     It can be seen from the above embodiment that the hollowed-out region can be an opening structure in the reflective layer  103 , and the projection of the chip body  106  on the substrate  101  can also cover all the projections of the pad layer on the substrate  101 . At this time, the reflective layer  103  is at least partially disposed on the surface of the substrate. In the embodiment of the present application, the structure of the backlight module in this case is described by taking the hollowed-out region as an opening structure in the reflective layer  103  as an example.  FIG.  5    is a partial top view of a third backlight module provided by an embodiment of the present application.  FIG.  6    is a cross-sectional view of the backlight module shown in  FIG.  5    along the line III-III. As shown in  FIG.  5    and  FIG.  6   , a projection of the reflective layer  103  on the substrate  101  includes an outer edge  1031  and an inner edge  1032 . The projection of the edge of the hollowed-out region on the substrate  101  is the above-mentioned inner edge  1032 . The light-emitting chip is mounted on the substrate  101  through the hollowed-out region. Wherein, the outer edge  1031  surrounds the projection of the light-emitting chip on the substrate  101 , is spaced from the projection of the light-emitting chip on the substrate  101 , and the inner edge  1032  is at least partially positioned within the coverage of the projection of the light-emitting chip on the substrate  101 . 
     Specifically, the projection of the light-emitting chip on the substrate  101  is rectangular, the outer edge  1031  encloses a closed region and the closed region is rectangular, and the outer edge  1031  is spaced from the projection of the light-emitting chip on the substrate  101 . It should be noted that the projection of the light-emitting chip on the substrate  101  can also be square, circular, or other shapes, which are mainly determined according to a shape of the light-emitting chip. A shape of the closed region enclosed by the outer edge  1031  can also be square, circular, or other shapes, which can be flexibly adjusted by those skilled in the art according to actual application requirements. 
     The inner edge  1032  encloses a closed region and the closed region is rectangular. The inner edge  1032  is positioned within the projection of the light-emitting chip on the substrate  101 , and a distance between the inner edge  1032  and the projection of the light-emitting chip on the substrate  101  is greater than a first predetermined value. Wherein, the first predetermined value can be flexibly adjusted by those skilled in the art according to actual application requirements. It should be noted that the closed region enclosed by the inner edge  1032  can also be square, circular, or other shapes, and those skilled in the art can flexibly adjust according to actual application requirements. The closed region enclosed by the inner edge  1032  can also coincide with the projection of the light-emitting chip on the substrate  101 , that is, there is no distance between the inner edge  1032  and the projection of the light-emitting chip on the substrate  101 . 
     It can be seen from the above embodiment that the hollowed-out region can also be a plurality of spaced opening structures in the reflective layer  103 , and the projection of the chip body  106  on the substrate  101  can also cover all the projections of the pad layer on the substrate  101 . At this time, the reflective layer  103  is at least partially disposed on the surface of the substrate. The embodiment of the present application takes the hollowed-out region as an example of the two spaced opening structures in the reflective layer  103  as an example to describe the structure of the backlight module in this case. The two opening structures of the hollowed-out region are respectively called the first hollowed-out sub-region and the second hollowed-out sub-region.  FIG.  7    is a schematic partial top view of a fourth backlight module provided by an embodiment of the present application. As shown in  FIG.  7   , a projection of the reflective layer  103  on the substrate  101  includes an outer edge  1031  and an inner edge  1032 , and the inner edge  1032  includes a first inner edge  10321  and a second inner edge  10322  spaced apart. A projection of the first hollowed-out sub-region on the substrate  101  is the afore-mentioned first inner edge  10321 , and a projection of the second hollowed-out sub-region on the substrate  101  is the afore-mentioned second inner edge  10322 . Wherein, the outer edge  1031  surrounds a projection of the light-emitting chip on the substrate  101 , and is spaced from the projection of the light-emitting chip on the substrate  101 . The first inner edge  10321  and the second inner edge  10322  are at least partially positioned within a coverage of the projection of the light-emitting chip on the substrate  101 . 
     Specifically, the projection of the light-emitting chip on the substrate  101  is rectangular, the outer edge  1031  encloses a closed region and the closed region is rectangular, and the outer edge  1031  is spaced from the projection of the light-emitting chip on the substrate  101 . It should be noted that the projection of the light-emitting chip on the substrate  101  can also be square, circular, or other shapes, which are mainly determined according to a shape of the light-emitting chip. A shape of the closed region enclosed by the outer edge  1031  can also be square, circular, or other shapes, which can be flexibly adjusted by those skilled in the art according to actual application requirements. 
     The first inner edge  10321  encloses a closed region and the closed region is rectangular. The first inner edge  10321  is positioned within the projection of the light-emitting chip on the substrate  101 , and a distance between the first inner edge  10321  and the projection of the light-emitting chip on the substrate  101  is greater than a first predetermined value. Wherein, the first predetermined value can be flexibly adjusted by those skilled in the art according to actual application requirements. It should be noted that the closed region enclosed by the first inner edge  10321  can also be square, circular, or other shapes, and those skilled in the art can flexibly adjust according to actual application requirements. The closed region enclosed by the first inner edge  10321  can also coincide with the projection of the light-emitting chip on the substrate  101 , that is, there is no distance between the first inner edge  10321  and the projection of the light-emitting chip on the substrate  101 . 
     The second inner edge  10322  encloses a closed region and the closed region is rectangular. The second inner edge  10322  is positioned within the projection of the light-emitting chip on the substrate  101 , and a distance between the second inner edge  10322  and the projection of the light-emitting chip on the substrate  101  is greater than the first predetermined value. Wherein, the first predetermined value can be flexibly adjusted by those skilled in the art according to actual application requirements. It should be noted that the closed region enclosed by the second inner edge  10322  can also be square, circular, or other shapes, and those skilled in the art can flexibly adjust according to actual application requirements. The closed region enclosed by the second inner edge  10322  can also coincide with the projection of the light-emitting chip on the substrate  101 , that is, there is no distance between the second inner edge  10322  and the projection of the light-emitting chip on the substrate  101 . 
     It should be noted that a cross-sectional view of the backlight module shown in  FIG.  7    along the line IV-IV is shown in  FIG.  6   . Since the cross-sectional structure of the backlight module shown in  FIG.  6    is similar to the cross-sectional structure of the backlight module shown in  FIG.  3   , and the cross-sectional structure of the backlight module shown in  FIG.  3    has been described in detail in the above-mentioned embodiment, it will not be repeated here. 
     It is understandable that compared with the light-emitting region  10  shown in  FIG.  5    and  FIG.  6   , the light-emitting region  10  shown in  FIG.  7    is further disposed with a reflective layer  103  between the first hollowed-out sub-region and the second hollowed-out sub-region. That is, an area of the reflective layer  103  is larger, so that the luminous efficiency of the backlight module can be further improved. 
     As a preferred embodiment, in an embodiment of the present application, dimensions of a first pad  1021 , a second pad  1022 , a first conductor  1041 , a second conductor, a chip body  106 , a first pin  1051 , a second pin  1052 , and a reflective layer  103  in the light-emitting region  10  will be described. 
     In order to make a distance between the reflective layer  103  and the chip body  106  in a direction perpendicular to the substrate  101  greater than a second predetermined value, conductive materials can be used to make a thicker first conductor  1041  and second conductor, for example, conductive glue (such as ACF) or use solder paste to make the first conductor  1041  and the second conductor with a thickness of about 35 microns. Alternatively, using a reflective material to make an ultra-thin reflective layer  103 , for example, using white oil to make the reflective layer  103  with a thickness of 1-30 microns. Alternatively, increasing thicknesses of the first the pin  1051  and the second pin  1052  so that the thicknesses of the first pin  1051  and the second pin  1052  range between 0.1-50 microns. Alternatively, increasing thicknesses of the first pad  1021  and the second pad  1022 , the thicknesses of the first pad  1021  and the second pad  1022  range between 0.1-50 microns. It should be noted that the above-mentioned multiple adjustment means can be used at same time to ensure that the distance between the reflective layer  103  and the chip body  106  in the direction perpendicular to the substrate  101  is greater than the second predetermined value. 
     As a preferred embodiment, an embodiment of the present application specifically describes dimensions of the light-emitting region  10  shown in  FIG.  2    and  FIG.  3   . As shown in  FIG.  2    and  FIG.  3   , a length of the light-emitting chip is M, a distance between an edge of the light-emitting chip and an edge of the first pin  1051  is L, a distance between an edge of the reflective layer  103  and an edge of the first pin  1051  is D, a thickness of the reflective layer  103  is T, a thickness of the first pin  1051  is Tp, a thickness of the conductor  1041  is Tw, a distance between the first pin  1051  and the second pin  1052  is A, and a width of the first pin  1051  is W, where W=(M−2L−A)/2. Wherein, W&gt;15 microns, L&gt;33 microns, A&gt;21 microns, and M&gt;80 microns. 
       FIG.  8    is a flowchart of a manufacturing method of a backlight module according to an embodiment of the present application. As shown in  FIG.  8   , the manufacturing method of the backlight module includes: 
     step S 1 , providing a substrate  101 , and fabricating a reflective layer  103  with a hollowed-out region on the substrate  101 ; and 
     step S 2 , electrically connecting a light-emitting chip to the substrate  101  in the hollowed-out region, wherein a projection of an edge of the hollowed-out region on the substrate  101  is at least partially positioned within a coverage of a projection of the light-emitting chip on the substrate  101 . 
     It should be noted that the structure of the backlight module manufactured by the method disposed in the embodiments of the present application has been described in detail in the above-mentioned embodiments, and will not be repeated here. In each of light-emitting region of the backlight module, since the outer edge  1031  of the reflective layer  103  projected on the substrate  101  surrounds the projection of the light-emitting chip on the substrate  101  and is spaced from the projection of the light-emitting chip on the substrate  101 , and the inner edge  1032  of the reflective layer  103  projected on the substrate  101  is at least partially positioned within the coverage of the projection of the light-emitting chip on the substrate  101 , therefore, the light originally irradiated by the light-emitting chip on the substrate  101 , the first pad  1021 , or the second pad  1022  will irradiate to the reflective layer  103 , and be reflected by the reflective layer  103  and then emitted from the backlight module, thereby improving the luminous efficiency of the backlight module. 
       FIG.  9    is a schematic structural diagram of a liquid crystal display device provided by an embodiment of the present application. As shown in  FIG.  9   , the liquid crystal display device  100  includes a liquid crystal display panel  2  and the backlight module  1  described in the foregoing embodiment. 
     It should be noted that the structure of the backlight module included in the liquid crystal display device disposed in the embodiments of the present application has been described in detail in the above-mentioned embodiments, and will not be repeated here. In each of light-emitting region of the backlight module, since the outer edge  1031  of the reflective layer  103  projected on the substrate  101  surrounds the projection of the light-emitting chip on the substrate  101  and is spaced from the projection of the light-emitting chip on the substrate  101 , and the inner edge  1032  of the reflective layer  103  projected on the substrate  101  is at least partially positioned within the coverage of the projection of the light-emitting chip on the substrate  101 . Therefore, the light originally irradiated by the light-emitting chip on the substrate  101 , the first pad  1021 , or the second pad  1022  will irradiate to the reflective layer  103 , and be reflected by the reflective layer  103  and then emitted from the backlight module, thereby improving the luminous efficiency of the backlight module. 
     It can be understood that for those of ordinary skill in the art, equivalent replacements or changes can be made according to the technical solutions of the present application and its application concept, and all these changes or replacements shall fall within the protection scope of the appended claims of the present application.