Circuit board, light-emitting apparatus, backlight module, and liquid crystal display apparatus

Abstract

Embodiments of the present disclosure relate to the technical field of display, and provide a circuit board. The circuit board has a first surface and a second surface which are opposite to each other, wherein the first surface is used for being connected to a light-emitting device. The circuit board comprises a second insulating layer, a first wiring layer, a first insulating layer, and a second wiring layer which are sequentially stacked in the direction from the second surface to the first surface; the first wiring layer comprises a first wire, the first wire being used for grounding; the second wiring layer comprises a second wire, the second wire being electrically connected to a positive electrode of the light-emitting device; and the second surface of the circuit board comprises a ground area, the part of the first wire located in the ground area is exposed out of the second surface, and the orthographic projection of the second wire on the second surface is located outside the ground area. According to the embodiments of the present disclosure, in practical use of the circuit board, when the ground area of the circuit board is broken or punctured, the possibility that the first wire and the second wire are short-circuited to generate a large current can be reduced, thereby reducing the possibility of burnout in a liquid crystal display apparatus caused by the large current.

Description

Circuit board, light-emitting device, backlight module and liquid crystal display device

[0001] This application claims priority to Chinese patent application No. 202311576401.7 filed on November 23, 2023, with invention name “Circuit board, light-emitting device, backlight module and liquid crystal display device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present disclosure relate to the field of display technology, and in particular to a circuit board, a light-emitting device, a backlight module, and a liquid crystal display device. Background Art

[0003] The backlight module is one of the important structures of liquid crystal display devices. The backlight module usually uses a light-emitting device to provide light. The light-emitting device includes a circuit board and multiple light-emitting devices distributed on the surface of the circuit board.

[0004] Summary of the Invention

[0005] The embodiments of the present disclosure provide a circuit board, a light-emitting device, a backlight module, and a liquid crystal display device, which can reduce the possibility of components in the liquid crystal display device being burned due to high temperatures. The technical solution is as follows:

[0006] On the one hand, a circuit board is provided, which has a first surface and a second surface relative to each other, the first surface being used to connect a light-emitting device; the circuit board includes a second insulating layer, a first wiring layer, a first insulating layer, and a second wiring layer stacked in sequence from the second surface to the first surface, the first wiring layer including a first trace, the first trace being used for grounding, the second wiring layer including a second trace, the second trace being electrically connected to the positive electrode of the light-emitting device; the second surface of the circuit board has a grounding area, the portion of the first trace located in the grounding area is exposed on the second surface, and the orthographic projection of the second trace on the second surface is located outside the grounding area.

[0007] Optionally, the first wiring layer also includes a first supporting structure, the orthographic projection of the first supporting structure on the first surface does not overlap with the orthographic projection of the first routing line on the first surface, and the orthographic projection of the first supporting structure on the first surface at least partially overlaps with the orthographic projection of the second routing line on the first surface.

[0008] Optionally, a dimension of the first supporting structure in the width direction of the circuit board is greater than or equal to 1 / 5 of the width of the circuit board, and less than or equal to the width of the circuit board.

[0009] Optionally, the first supporting structure is made of copper, aluminum, copper alloy or aluminum alloy.

[0010] Optionally, the second wiring layer also includes a second supporting structure, the orthographic projection of the second supporting structure on the first surface does not overlap with the orthographic projection of the second routing line on the first surface, and the orthographic projection of the second supporting structure on the first surface at least partially overlaps with the orthographic projection of the first routing line on the first surface.

[0011] Optionally, a dimension of the second supporting structure in the width direction of the circuit board is greater than or equal to 1 / 5 of the width of the circuit board, and less than or equal to the width of the circuit board.

[0012] Optionally, the second supporting structure is made of copper, aluminum, copper alloy or aluminum alloy.

[0013] Optionally, the second wiring layer further includes at least one first pad group, each of the first pad groups includes a plurality of pad pairs arranged along a first direction, each of the pad pairs includes a first pad and a second pad, the first pad is exposed on the first surface and is connected to the positive electrode of the light-emitting device, and the second pad is exposed on the first surface and is connected to the negative electrode of the light-emitting device; in each of the first pad groups, the second pad of the first pad pair is connected to the first pad of the second pad pair, and the first pad pair and the second pad pair are two adjacent pad pairs in the first direction.

[0014] Optionally, the second wiring layer includes a plurality of first pad groups arranged along the first direction.

[0015] Optionally, the second wiring layer also includes at least one second pad group, the second pad group includes multiple pad pairs arranged along the first direction; the circuit board also includes multiple electrostatic protection tubes, the multiple electrostatic protection tubes are connected one by one to the multiple pad pairs in the second pad group, and the multiple electrostatic protection tubes are located on the first surface; the two ends of each of the first pad groups are electrically connected to the first trace through the electrostatic protection tube.

[0016] Optionally, the circuit board includes a device placement portion and a connecting portion, the at least one first pad group is located in the device placement portion, the device placement portion is in the shape of an elongated strip, and the connecting portion is connected to the device placement portion and is located on one side of the device placement portion in a direction perpendicular to the length direction of the device placement portion.

[0017] Optionally, the first insulating layer has a first via and a second via, and the first wiring layer also includes a third route and a fourth route; one end of the third route is electrically connected to one of the second pads in a first pad group through the first via, and the other end of the third route is located at the connecting portion; one end of the fourth route is electrically connected to the second route through the second via, and the other end of the fourth route is located at the connecting portion.

[0018] On the other hand, a light-emitting device is provided, comprising a plurality of light-emitting devices and any one of the aforementioned circuit boards, wherein the plurality of light-emitting devices are connected to a first surface of the circuit board.

[0019] On the other hand, a backlight module is provided. The backlight module includes a back plate and the aforementioned light-emitting device, wherein the light-emitting device is connected to the back plate.

[0020] On the other hand, a liquid crystal display device is provided. The liquid crystal display device includes the aforementioned backlight module and a liquid crystal display panel. The backlight module is used to provide a light source for the liquid crystal display panel.

[0021] The technical solution provided by the present disclosure has at least the following beneficial effects: by arranging the orthographic projection of the second trace in the circuit board on the second surface to be outside the grounding area, when the grounding area of ​​the circuit board is damaged or punctured during actual use of the circuit board, the possibility of a short circuit between the first trace and the second trace generating a large current is reduced, thereby reducing the possibility of burning of the liquid crystal display device due to the large current. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] FIG1 is a schematic diagram of a partial planar structure of a first wiring layer and a second wiring layer in a circuit board provided by an embodiment of the present disclosure;

[0024] FIG2 is a schematic diagram of a cross-sectional structure of a circuit board provided in an embodiment of the present disclosure;

[0025] FIG3 is a circuit diagram of a circuit board provided by an embodiment of the present disclosure when multiple LEDs are mounted on the circuit board;

[0026] FIG4 is a schematic diagram of another partial planar structure of a first wiring layer and a second wiring layer in a circuit board provided by an embodiment of the present disclosure;

[0027] FIG5 is a schematic diagram of a partial planar structure of a first wiring layer and a second wiring layer in another circuit board provided by an embodiment of the present disclosure;

[0028] FIG6 is a schematic diagram of a cross-sectional structure of another circuit board provided in an embodiment of the present disclosure;

[0029] FIG7 is a schematic cross-sectional view of a light emitting device provided by an embodiment of the present disclosure;

[0030] FIG8 is a schematic diagram of a partial planar structure of a light emitting device provided by an embodiment of the present disclosure;

[0031] FIG9 is a schematic cross-sectional view of a backlight module provided in an embodiment of the present disclosure;

[0032] FIG10 is a schematic diagram of a partial planar structure of a backlight module provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0034] The terms used in the embodiments of the present disclosure are only used to explain the embodiments of the present disclosure and are not intended to limit the present disclosure. Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should be the ordinary meanings understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second", "third" and similar words used in the patent application specification and claims of this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "a" do not indicate a quantitative limitation, but rather indicate the presence of at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" cover the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. The directional terms mentioned in the present disclosure, such as "top", "bottom", "up", "down", "left" or "right", etc., are only used to refer to the directions of the drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present disclosure, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0035] In the related art, the light-emitting device of the backlight module generally includes a circuit board and a plurality of light-emitting devices distributed on the surface of the circuit board. The circuit board includes a first surface and a second surface relative to each other, and the first surface is used to connect the light-emitting device. In the direction from the second surface to the first surface, the circuit board includes a second insulating layer, a first wiring layer, a first insulating layer and a second wiring layer stacked in sequence. The first wiring layer includes a first trace, the first trace is used for grounding, and a portion of the first trace is exposed on the second surface, and the second wiring layer includes a second trace, and the second trace is electrically connected to the positive electrode of the light-emitting device. The portion of the first trace exposed on the second surface can be referred to as a grounding area. At least a portion of the orthographic projection of the second trace on the second surface is located within the grounding area.

[0036] During the actual use of the circuit board (for example, when assembling a backlight module using a light-emitting device including the circuit board), the exposed portion of the first trace needs to be grounded by means of conductive tape or other methods. During this process, the grounding area of ​​the circuit board may be damaged or punctured. Since at least part of the orthographic projection of the second trace on the second surface is located within the grounding area, if the grounding area is damaged, a short circuit will occur between the first trace and the second trace, generating a large current. The high temperature generated by the large current may burn other structures within the liquid crystal display device.

[0037] To this end, an embodiment of the present disclosure provides a circuit board, which reduces the possibility of burning in a liquid crystal display device due to high temperature caused by a large current generated by short-circuiting the first and second lines when the grounding area is damaged or punctured by arranging the orthographic projection of the second line in the circuit board on the second surface outside the grounding area.

[0038] Figure 1 is a schematic diagram of the partial planar structure of the first and second wiring layers within a circuit board provided by an embodiment of the present disclosure, wherein portion (a) of Figure 1 is a schematic diagram of the partial planar structure of the second wiring layer within the circuit board, and portion (b) of Figure 1 is a schematic diagram of the partial planar structure of the first wiring layer 11 within the circuit board. Figure 2 is a schematic diagram of the cross-sectional structure of a circuit board provided by an embodiment of the present disclosure, and Figure 2 includes a schematic diagram of the cross-sectional structure taken along the CC section line in Figure 1.

[0039] As shown in Figures 1 and 2, a circuit board 1 has opposing first and second surfaces A and B. First surface A is used to connect a light-emitting device (not shown). Circuit board 1 includes a second insulating layer 14, a first wiring layer 11, a first insulating layer 12, and a second wiring layer 13, stacked sequentially from second surface B to first surface A. First wiring layer 11 includes a first trace 111, which is used for grounding and can be referred to as a ground line. Second wiring layer 13 includes a second trace 131, which is electrically connected to the positive electrode of the light-emitting device. Second surface B of circuit board 1 has a grounding region 10. The portion of first trace 111 located in grounding region 10 is exposed on second surface B. That is, second insulating layer 14 has an opening that exposes a portion of first trace 111. The orthographic projection of second trace 131 on second surface B is located outside grounding region 10. In other words, first trace 111 and second trace 131 are staggered in the grounding region 10 and in the vicinity of grounding region 10. In this way, when the exposed portion of the first trace 111 is grounded by means of conductive tape or the like, since the orthographic projection of the second trace 131 on the second surface B is located outside the grounding area 10, even if the grounding area 10 of the circuit board 1 is damaged or punctured, the possibility of a short circuit between the first trace 111 and the second trace 131 and the generation of a large current is small, thereby reducing the possibility of high temperatures generated by the large current burning other structures in the liquid crystal display device.

[0040] Exemplarily, the first wiring layer 11 further includes a first support structure 112. The orthographic projection of the first support structure 112 on the first surface A does not overlap with the orthographic projection of the first trace 111 on the first surface A, and the orthographic projection of the first support structure 112 on the first surface A at least partially overlaps with the orthographic projection of the second trace 131 on the first surface A. Because the circuit board 1 employs the staggered design of the first trace 111 and the second trace 131 in and near the grounding region 10 as described above, without the first support structure 112, the support force of the circuit board 1 near the grounding region 10 is relatively low. The provision of the first support structure 112 can alleviate the problem of relatively low support force near the grounding region 10 caused by the staggered design of the first trace 111 and the second trace 131.

[0041] Optionally, since the second wiring layer 13 needs to be connected to the light-emitting device, multiple pads for connecting the light-emitting device need to be set on the second wiring layer 13, resulting in a relatively dense routing pattern of the second wiring layer 13 and a smaller area that can be used to set the support structure. Therefore, a first support structure 112 is set on the first wiring layer 11, and no support structure is set on the second wiring layer 13.

[0042] Exemplarily, the first support structure 112 is made of a metal material. Optionally, the first support structure 112 is made of copper, aluminum, a copper alloy, or an aluminum alloy. The first support structure 112 can be manufactured on the same layer as other traces (e.g., the first trace 111) in the first wiring layer 11, saving process time.

[0043] For example, the dimension of the first support structure 112 in the width direction of the circuit board 1 is greater than or equal to 1 / 5 of the width of the circuit board 1, and less than or equal to the width of the circuit board 1. The first support structure 112 within this width range will not be too narrow to cause insufficient support force.

[0044] Exemplarily, as shown in FIG1 , the second wiring layer 13 further includes at least one first pad group 133 . Each first pad group includes a plurality of pad pairs 1330 arranged along a first direction x. Each pad pair 1330 includes a first pad 1330a and a second pad 1330b . The first pad 1330a is exposed on the first surface A and connected to the anode of the light-emitting device, while the second pad 1330b is exposed on the first surface A and connected to the cathode of the light-emitting device. In each first pad group 133 , the second pad 1330b of the first pad pair is connected to the first pad 1330a of the second pad pair. The first and second pad pairs are adjacent pad pairs in the first direction. Optionally, the first direction is the lengthwise direction of the circuit board 1 . The first pad groups 133 are designed to facilitate mounting multiple light-emitting devices. Within a first pad group 133 , the light-emitting devices corresponding to the plurality of pad pairs 1330 are connected in series. Here, the first direction x is the lengthwise direction of the circuit board 1 .

[0045] For example, as shown in FIG1 , the second wiring layer 13 includes a plurality of first solder pad groups 133 arranged along a first direction. Because the total input voltage of the circuit board 1 is limited, if all light-emitting devices on the circuit board 1 are connected in series, the voltage to each light-emitting device may be insufficient, preventing it from illuminating. Therefore, based on the total input voltage of the circuit board 1 and the voltage required to illuminate each light-emitting device, the multiple light-emitting devices can be designed as multiple groups of light-emitting devices connected in parallel. Within each group, multiple light-emitting devices are connected in series. Accordingly, multiple first solder pad groups 133 are provided on the second wiring layer 13.

[0046] Exemplarily, as shown in FIG1 , the second wiring layer 13 further includes at least one second pad group 134 , which includes a plurality of pad pairs 1340 arranged along a first direction. The circuit board 1 further includes a plurality of electrostatic protection tubes (not shown in FIG1 ), which are connected one-to-one to the plurality of pad pairs 1340 in the second pad group 134 , and are located on the first surface A. The two ends of each first pad group 133 are electrically connected to the first trace 111 via an electrostatic protection tube. An electrostatic protection tube is provided between the two ends of the first pad group 133 and the first trace 111 (ground line) to protect the light-emitting device.

[0047] Optionally, two electrostatic protection tubes are provided between one end of a first pad group 133 and the first trace 111 (ground line), and the directions of the two electrostatic protection tubes are opposite.

[0048] 1 , in the second direction y, at least one second pad group 134 is located on one side of the first pad group 133, and the second direction y intersects the first direction x. Alternatively, as shown in FIG1 , in the first direction x, two second pad groups 134 are located at both ends of one first pad group 133.

[0049] FIG3 is a circuit diagram of a circuit board provided by an embodiment of the present disclosure when multiple LEDs are installed on the circuit board. In conjunction with FIG1 and FIG3, the light-emitting device can be an LED (Light Emitting Diode). Optionally, 88 LEDs can be placed on a circuit board 1, and the 88 LEDs are divided into 8 LED groups, and these 8 LED groups are connected in parallel. An LED group includes 11 LEDs connected in series. Optionally, a voltage of about 2V is required to light up an LED, and the total input voltage of a circuit board is about 22V. The above design can light up all the multiple LEDs.

[0050] Optionally, in a circuit board 1, it was found through actual measurement that the resistance between the second trace 131 and the portion of the first trace 111 located in the grounding area 10 is about 0.5Ω to 5Ω. If the grounding area 10 of the circuit board 1 is damaged or punctured, resulting in a short circuit between the first trace 111 and the second trace 131, the heat generated after 2 seconds to 10 seconds of the short circuit is enough to make the light bar emit white smoke and gradually deform, and the high temperature also burns other backlight components in the backlight module including the circuit board 1, as well as related components in the display screen located near the circuit board 1, such as causing the polarizer and the rubber frame to become charred and deformed. The embodiment of the present disclosure reduces the possibility of a short circuit between the first trace 111 and the second trace 131 and the generation of a large current by staggering the first trace 111 and the second trace 131, thereby reducing the possibility of the high temperature generated by the large current burning other structures in the liquid crystal display device.

[0051] In other possible embodiments, different numbers of first pad groups 133 and different numbers of pad pairs 1330 can be designed within a first pad group 133 according to the total input voltage of the circuit board and the voltage required to light up a single light-emitting device.

[0052] FIG4 is a schematic diagram of another partial planar structure of the first and second wiring layers within a circuit board provided by an embodiment of the present disclosure. In conjunction with FIG1 and FIG4 , the circuit board 1 includes a device placement portion 101 and a connection portion 102. At least one first solder pad group 133 is located within the device placement portion 101. The device placement portion 101 is in the shape of an elongated strip. The connection portion 102 is connected to the device placement portion 101 and is located on one side of the device placement portion 101 in a direction perpendicular to the length of the device placement portion 101. The device placement portion 101 facilitates the placement of light-emitting devices, and the connection portion 102 facilitates connection to other structures within the liquid crystal display device. This design allows both the input and output terminals of the circuit board 1 to be located on the connection portion 104, thereby facilitating connection with other components (e.g., a driver chip that controls the circuit board).

[0053] For example, as shown in Figures 1 and 4, the first insulating layer 12 has a first via 121 and a second via 122, and the first wiring layer 11 further includes a third trace 113 and a fourth trace 114. One end of the third trace 113 is electrically connected to a second pad 1330b in a first pad group 133 through the first via 121, and the other end of the third trace 113 is located at the connection portion 102. One end of the fourth trace 114 is electrically connected to the second trace 131 through the second via 122, and the other end of the fourth trace 114 is located at the connection portion 102. The provision of the first via 121 and the second via 122 facilitates relatively even distribution of multiple traces in the first wiring layer 11 and the second wiring layer 13 without affecting the electrical connection relationship, thereby preventing the traces in the second wiring layer from being too dense and the traces in the first wiring layer from being too sparse. It is also possible to connect the input end of the circuit board 1 to the positive electrode of a group of light-emitting devices through the fourth trace 114 of the first wiring layer 11, the second via 122 in the first insulating layer 12, and the second trace 131 of the second wiring layer 13 in sequence; the output end of the circuit board 1 can be connected to the negative electrode of a group of light-emitting devices through the third trace 113 of the first wiring layer 11 and the first via 121 in the first insulating layer 12 in sequence.

[0054] It should be noted that the first via 121 and the second via 122 in part (a) of Figure 1 and part (b) of Figure 1 refer to the positive projections of the first via 121 and the second via 122 in the first insulating layer 13 on the side of the first wiring layer 11 and the second wiring layer 13 close to the first surface A, respectively.

[0055] 2 , the circuit board 1 further includes a third insulating layer 15 , which is located on a side of the second wiring layer 13 away from the second surface B. The third insulating layer 15 can protect the second wiring layer 13 .

[0056] Optionally, as shown in FIG2 , the third insulating layer 15 has a plurality of openings so that the light emitting device can be connected to pads (eg, the second pads 102 b shown in FIG2 ) on the first wiring layer 11 through the openings.

[0057] Optionally, the circuit board 1 may be an FPC (Flexible Printed Circuit) or a PCB (printed circuit board).

[0058] Optionally, a grounding region 10 and a corresponding first supporting structure 112 located near the grounding region 10 are provided at both ends of the device arrangement portion 101 .

[0059] Optionally, the first insulating layer 12, the second insulating layer 14, and the third insulating layer 15 may be made of PI (Polyimide) or PET (polyethylene glycol terephalate). PI or PET has good bending properties, which can ensure the overall bending performance of the FPC.

[0060] Figure 5 is a schematic diagram of the partial planar structure of the first and second wiring layers within another circuit board provided by an embodiment of the present disclosure, wherein portion (a) of Figure 5 is a schematic diagram of the partial planar structure of the second wiring layer within the circuit board, and portion (b) of Figure 5 is a schematic diagram of the partial planar structure of the first wiring layer 11 within the circuit board. Figure 6 is a schematic diagram of the cross-sectional structure of another circuit board provided by an embodiment of the present disclosure, and Figure 6 includes the schematic diagram of the cross-sectional structure along the DD section line in Figure 5.

[0061] As shown in Figures 5 and 6 , compared to the embodiment shown in Figures 1 and 2 , the difference is that the second wiring layer 13 further includes a second support structure 132. The orthographic projection of the second support structure 132 on the first surface A does not overlap with the orthographic projection of the second trace 131 on the first surface A, and the orthographic projection of the second support structure 132 on the first surface A at least partially overlaps with the orthographic projection of the first trace 111 on the first surface A. The provision of the second support structure 132 can further alleviate the problem of weak supporting force near the grounding area 10 caused by the staggered design of the first trace 111 and the second trace 131.

[0062] Exemplarily, the second support structure 132 is made of a metal material. Optionally, the second support structure is made of copper, aluminum, a copper alloy, or an aluminum alloy. The second support structure 132 can be manufactured on the same layer as other traces (e.g., the second trace 131) in the second wiring layer 13, saving process time.

[0063] Optionally, the dimension of the second support structure 132 in the width direction of the circuit board 1 is greater than or equal to 1 / 5 of the width of the circuit board 1, and less than or equal to the width of the circuit board. Within this width range, the second support structure 132 will not be too narrow, resulting in insufficient support force, nor will the metal second support structure 132 be too wide, causing leakage on the sidewalls of the circuit board 1.

[0064] Optionally, a grounding region 10 and a corresponding first supporting structure 112 and a second supporting structure 132 located near the grounding region 10 are provided at both ends of the device arrangement portion 101 .

[0065] Optionally, as shown in FIG5 , the width of the first support structure 112 is greater than the width of the second support structure 132. Since the second wiring layer 13 needs to be connected to the light-emitting device, a plurality of pads for connecting to the light-emitting device need to be provided on the second wiring layer 13. This results in a denser routing pattern of the second wiring layer 13 and a smaller area available for providing the support structure. Therefore, the width of the first support structure 112 on the first wiring layer 11 is greater than the width of the second support structure 132 on the second wiring layer 13.

[0066] The present disclosure also provides a method for manufacturing a circuit board, the method comprising: manufacturing a second insulating layer, a first wiring layer, a first insulating layer, and a second wiring layer to obtain a circuit board. The circuit board has a first surface and a second surface relative to each other, the first surface being used to connect the light-emitting device, and the second insulating layer, the first wiring layer, the first insulating layer, and the second wiring layer being stacked in sequence from the second surface to the first surface. The first wiring layer includes a first trace, the first trace being used for grounding, the second wiring layer includes a second trace, the second trace being electrically connected to the positive electrode of the light-emitting device; the circuit board includes a grounding area, the portion of the first trace located in the grounding area is exposed on the second surface, and the orthographic projection of the second trace on the second surface is located outside the grounding area.

[0067] The following is another method for manufacturing a circuit board provided in an embodiment of the present disclosure, which can be used to manufacture the circuit board shown in FIG1 . The manufacturing method includes:

[0068] In the first step, a first insulating material layer is formed by deposition, for example, and a first metal material layer is formed on one side of the first insulating material layer by electroplating, for example.

[0069] In the second step, the first insulating material layer is patterned to obtain a first insulating layer, the first insulating layer including a plurality of vias. A second metal material layer is formed on the other side of the first insulating layer by, for example, electroplating, and the second metal material layer is connected to the first metal material layer through the plurality of vias in the first insulating layer.

[0070] In the third step, the first metal material layer and the second metal material layer are patterned respectively to obtain a first wiring layer and a second wiring layer.

[0071] In the fourth step, a second insulating material layer is formed entirely on the side of the first wiring layer remote from the first insulating layer, for example, by deposition. A third insulating material layer is also formed entirely on the side of the second wiring layer remote from the first insulating layer, for example, by deposition. The second and third insulating material layers are patterned to form second and third insulating layers, respectively. The opening in the second insulating layer exposes a portion of the first wiring layer and serves as a grounding region. The opening in the third insulating layer exposes a portion of the second wiring layer and serves as a connection to the light-emitting device.

[0072] Optionally, the patterning process includes processes such as photoresist coating, exposure, development, etching, and stripping.

[0073] Figure 7 is a schematic diagram of the cross-sectional structure of a light-emitting device provided in an embodiment of the present disclosure, and Figure 8 is a schematic diagram of the partial planar structure of a light-emitting device provided in an embodiment of the present disclosure, and Figure 8 is a top view of Figure 7. As shown in Figures 7 and 8, the light-emitting device includes a plurality of light-emitting devices 2 and any of the aforementioned circuit boards 1, and the plurality of light-emitting devices 2 are connected to the first surface A of the circuit board 1. The light-emitting device has the same effect as the aforementioned circuit board and will not be described in detail here. Optionally, the light-emitting device can be used for lighting; or, the light-emitting device is used to make a backlight module and provide a light source. Optionally, in combination with Figures 7 and 8, the plurality of electrostatic protection tubes 16 in the circuit board 1 are distributed on the side of the plurality of light-emitting devices 2 away from the light-emitting surface 20.

[0074] Optionally, the lighting device further includes a control circuit board, which can control the total input voltage of the circuit board.

[0075] Figure 9 is a schematic diagram of the cross-sectional structure of a backlight module provided in an embodiment of the present disclosure, and Figure 10 is a schematic diagram of a partial planar structure of a backlight module provided in an embodiment of the present disclosure, with Figure 9 being a schematic diagram of the cross-sectional structure of Figure 10 taken along section line EE. As shown in Figures 9 and 10, the backlight module includes a backplate 4 and the aforementioned light-emitting device, which is connected to the backplate 4. The backplate 4 can serve as a support. This backlight module has the same effects as the aforementioned circuit board and will not be described in detail here.

[0076] 9 and 10 , the sidewall of the light emitting device is the light emitting surface 20. As shown in FIG7 and 8 , the sidewall of the light emitting device is perpendicular to the first surface A and parallel to the first direction x.

[0077] Optionally, as shown in Figures 9 and 10, the backlight module further includes a light guide plate 3. The light guide plate 3 has a light-emitting surface and a non-light-emitting surface relative to each other. In the embodiment shown in Figure 9, the light-emitting surface is the upper surface of the light guide plate 3. The light-emitting device is located on the side of the light guide plate 3, and the side of the light guide plate 3 is the light-incident surface. The light-incident surface contacts the light-emitting surface 20 of the light-emitting device 2. This backlight module is also called a side-entry backlight module. It should be noted that in Figure 10, in order to illustrate the positional relationship between the light-emitting device and the light guide plate, the back plate 4 is not shown.

[0078] Optionally, the first surface of the circuit board 1 is parallel to the light emitting surface of the light guide plate 3 .

[0079] Optionally, as shown in Figure 9 , the backlight module further includes a reflective sheet 6. The reflective sheet 6 is located on the non-light-emitting surface of the light guide plate 3. That is, in the embodiment shown in Figure 9 , the reflective sheet 6 is located on the lower surface of the light guide plate 3. Light emitted by the light-emitting device enters the light guide plate 3 from the side, and some of the light reaches the bottom of the light guide plate 3. The reflective sheet 6 is used to reflect this light back to the light-emitting surface of the light guide plate 3.

[0080] Optionally, as shown in FIG9 , the grounding area 10 of the circuit board 1 and the back plate 4 are respectively adhered to both sides of the conductive tape 5 , so that the grounding area 10 of the circuit board 1 is connected to the back plate 4 .

[0081] Optionally, the back plate 4 is made of metal material, such as iron. The back plate 4 made of metal material has high strength and is not easy to bend or deform. Moreover, the back plate 4 can also play a grounding role through the electrical connection of the conductive tape 5.

[0082] Optionally, the back plate 4 is a semi-enclosed structure, with a portion of the back plate 4 located between the anti-scattering sheet 6 and the bottom of the light-emitting device to provide support. A portion of the back plate 4 surrounds the light-emitting device and does not block the light-emitting surface 20 of the light-emitting device, thereby protecting the light-emitting device.

[0083] Optionally, the backlight module 4 further includes a fixing member, which is used to fix the light-emitting device on the back plate 3. The fixing member can be a clip or a screw.

[0084] An embodiment of the present disclosure further provides a liquid crystal display device, which includes the aforementioned backlight module and a liquid crystal display panel. The backlight module is used to provide a light source for the liquid crystal display panel.

[0085] Illustratively, the liquid crystal display device provided in the embodiments of the present disclosure may be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, or a navigator.

[0086] The liquid crystal display device has the same effects as the aforementioned circuit board, which will not be described in detail here.

[0087] The above are merely optional embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A circuit board, characterized in that: The circuit board has a first surface and a second surface opposite to each other, the first surface being used for connecting the light emitting device; The circuit board includes a second insulating layer, a first wiring layer, a first insulating layer, and a second wiring layer stacked in sequence in a direction from the second surface to the first surface, the first wiring layer includes a first wiring, the first wiring is used for grounding, the second wiring layer includes a second wiring, and the second wiring is electrically connected to the positive electrode of the light-emitting device; The second surface of the circuit board has a grounding area, a portion of the first trace located in the grounding area is exposed on the second surface, and an orthographic projection of the second trace on the second surface is located outside the grounding area.

2. The circuit board according to claim 1, characterized in that: The first wiring layer also includes a first supporting structure, the orthographic projection of the first supporting structure on the first surface does not overlap with the orthographic projection of the first routing line on the first surface, and the orthographic projection of the first supporting structure on the first surface at least partially overlaps with the orthographic projection of the second routing line on the first surface.

3. The circuit board according to claim 2, characterized in that: The dimension of the first supporting structure in the width direction of the circuit board is greater than or equal to 1 / 5 of the width of the circuit board and less than or equal to the width of the circuit board.

4. The circuit board according to claim 3, characterized in that: The first supporting structure is made of copper, aluminum, copper alloy or aluminum alloy.

5. The circuit board according to any one of claims 1 to 4, characterized in that: The second wiring layer also includes a second supporting structure, the orthographic projection of the second supporting structure on the first surface does not overlap with the orthographic projection of the second routing line on the first surface, and the orthographic projection of the second supporting structure on the first surface at least partially overlaps with the orthographic projection of the first routing line on the first surface.

6. The circuit board according to claim 5, characterized in that: A dimension of the second supporting structure in a width direction of the circuit board is greater than or equal to 1 / 5 of the width of the circuit board and less than or equal to the width of the circuit board.

7. The circuit board according to claim 6, characterized in that: The second supporting structure is made of copper, aluminum, copper alloy or aluminum alloy.

8. The circuit board according to any one of claims 1 to 4 and claims 6 to 7, characterized in that: The second wiring layer further includes at least one first pad group, each of the first pad groups includes a plurality of pad pairs arranged along a first direction, each of the pad pairs includes a first pad and a second pad, the first pad is exposed on the first surface and connected to the positive electrode of the light-emitting device, and the second pad is exposed on the first surface and connected to the negative electrode of the light-emitting device; In each of the first pad groups, the second pad of the first pad pair is connected to the first pad of the second pad pair, and the first pad pair and the second pad pair are two pad pairs adjacent to each other in the first direction.

9. The circuit board according to claim 8, characterized in that: The second wiring layer includes a plurality of first pad groups arranged along the first direction.

10. The circuit board according to claim 9, characterized in that: The second wiring layer further includes at least one second pad group, the second pad group including a plurality of pad pairs arranged along the first direction; The circuit board further comprises a plurality of electrostatic protection tubes, the plurality of electrostatic protection tubes are connected one by one with the plurality of pad pairs in the second pad group, and the plurality of electrostatic protection tubes are located on the first surface; Two ends of each of the first pad groups are electrically connected to the first wiring through the electrostatic protection tube.

11. The circuit board according to claim 8, characterized in that: The circuit board includes a device placement portion and a connecting portion, the at least one first pad group is located in the device placement portion, the device placement portion is in a strip shape, the connecting portion is connected to the device placement portion and is located on one side of the device placement portion in a direction perpendicular to the length direction of the device placement portion.

12. The circuit board according to claim 11, characterized in that: The first insulating layer has a first via hole and a second via hole, and the first wiring layer further includes a third routing line and a fourth routing line; One end of the third routing line is electrically connected to one of the second pads in a first pad group through the first via hole, and the other end of the third routing line is located at the connecting portion; One end of the fourth routing line is electrically connected to the second routing line through the second via hole, and the other end of the fourth routing line is located at the connecting portion.

13. A light emitting device, characterized in that: The light emitting device comprises a plurality of light emitting devices and a circuit board as claimed in any one of claims 1 to 12, wherein the plurality of light emitting devices are connected to a first surface of the circuit board.

14. A backlight module, characterized in that: The backlight module comprises a back plate and the light-emitting device as claimed in claim 13, and the light-emitting device is connected to the back plate.

15. A liquid crystal display device, characterized in that: The liquid crystal display device comprises the backlight module as claimed in claim 14 and a liquid crystal display panel, wherein the backlight module is used to provide a light source for the liquid crystal display panel.

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