Display panel and backlight display module

Abstract

The invention provides a display panel and a backlight display module. The display panel comprises a circuit board; the surface of the circuit board is covered with the solder mask layer, the solder mask layer is provided with a window, and the size of the window in the width direction is gradually reduced from the edge to the middle area in the length direction of the window; the bonding pad group is arranged in the open window, and the bonding pad group comprises two trapezoidal bonding pads which are symmetrically arranged along the length direction; and the chip is welded with the circuit board through the bonding pad group. According to the display panel, the welding of the chip and the circuit board is realized by adopting the trapezoidal bonding pad, the offset of the chip in the width direction can be reduced in the welding process, and the area of a hollow area except the bonding pad in the window is as small as possible because the window is in the shape of'wide at two ends and narrow in the middle ', so that the reflectivity of the display panel is improved.

Description

Technical Field

[0001] The present application relates to, and more particularly to, a display panel and a backlight display module. Background Art

[0002] Display panels typically consist of a circuit board and a light-emitting diode (LED) chip soldered to its surface. LED chips, also known as lamp beads, convert electrical energy into light, emitting light of a specific color and brightness. The display quality of a display panel is affected by a variety of factors, including the reliability of the solder joint between the chip and the circuit board and the reflectivity of the circuit board. Therefore, improving the solder joint reliability between the chip and the circuit board in a display panel and improving the reflectivity of the display panel have become challenges. Summary of the Invention

[0003] The present application provides a display panel and a backlight display module, which can improve the welding reliability between the chip and the circuit board in the display panel and improve the reflectivity of the display panel.

[0004] In a first aspect, a display panel is provided, comprising: a circuit board; a solder resist layer covering the surface of the circuit board, the solder resist layer being provided with a window, wherein along the length direction of the window, the width dimension of the window gradually decreases from the edge to the middle area; a pad group arranged in the window, the pad group comprising two trapezoidal pads symmetrically arranged along the length direction; and a chip, being soldered to the circuit board through the pad group.

[0005] In an embodiment of the present application, a solder mask is provided on the circuit board, and a window is provided on the solder mask. Two trapezoidal pads are symmetrically provided in the length direction of the window. Since the trapezoidal pads are used to realize the welding of the chip and the circuit board, the displacement of the chip in the width direction can be reduced during the welding process. Moreover, since the shape of the window is "wide at both ends and narrow in the middle", the area of ​​the hollow area in the window except the trapezoidal pad is made as small as possible, thereby improving the reflectivity of the display panel.

[0006] In a possible implementation, the window includes two trapezoidal regions symmetrically arranged along the length direction, and the middle region located between the two trapezoidal regions, and the trapezoidal regions are used to set the trapezoidal pad.

[0007] For example, the middle area is rectangular, the lower base of the trapezoidal area is located at the edge of the window parallel to the width direction, and the upper base of the trapezoidal area has the same size as the middle area in the width direction.

[0008] Since the window includes two trapezoidal areas symmetrically arranged along the length direction and an intermediate area located between the two trapezoidal areas, the shape of the window matches the shape of the trapezoidal pad, so that the area of ​​the hollow area in the window except the trapezoidal pad is as small as possible, thereby improving the reflectivity of the display panel.

[0009] In one possible implementation, the waist of the trapezoidal region is parallel to the waist of the trapezoidal pad. Optionally, taking into account actual process requirements, a gap is provided between the waist of the trapezoidal region and the waist of the trapezoidal pad. This can further reduce the hollow area and improve the reflectivity of the display panel.

[0010] In a possible implementation, an area occupied by the two trapezoidal pads in the window is larger than an area occupied by a hollow region in the window excluding the two trapezoidal pads.

[0011] In this implementation, compared with the scheme of trapezoidal pads and rectangular windows, the area of ​​the hollow region can be significantly reduced, so that the area of ​​the hollow region in the window is smaller than the area occupied by the trapezoidal pads.

[0012] The shape of the trapezoidal pad may be, for example, an isosceles trapezoid, thereby improving the welding performance between the trapezoidal pad and the chip.

[0013] The bottom of the trapezoidal pad may be located at an edge of the window parallel to the width direction, for example, so as to further reduce the area of ​​the hollow region.

[0014] In a possible implementation, two electrodes are provided on the side of the chip facing the circuit board, the two electrodes are respectively welded to the two trapezoidal pads, and the size of the chip in the width direction is the same as the width of the upper bottom of the trapezoidal pad.

[0015] In this implementation, when the width of the chip is the same as the width of the upper bottom of the trapezoidal pad, when the pad is still in liquid solder and has not completely solidified during the welding process, the chip is located on the surface of the liquid solder and the two end points of the upper bottom of the trapezoidal pad become the boundaries of the liquid solder, making it impossible for the chip to continue to move horizontally in the width direction, thereby limiting the chip in the width direction, reducing the chip's offset, and improving the welding reliability between the chip and the circuit board.

[0016] In one possible implementation, the size of the lower base of the trapezoidal pad is 1.5 to 2 times the size of the upper base. This can increase the area of ​​the trapezoidal pad, allowing the solder to be fully spread and increasing the soldering adhesion of the chip.

[0017] In one possible implementation, the chip is Mini-LED or Micro-LED.

[0018] In a second aspect, a backlight display module is provided, comprising the display panel described in the first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0020] Figure 1 and Figure 2 It is a schematic diagram of the welding scheme between the chip and the circuit board.

[0021] Figure 3 and Figure 4 This is a schematic diagram of another soldering solution between the chip and the circuit board.

[0022] Figure 5 This is a schematic diagram showing chip displacement during soldering.

[0023] Figure 6 and Figure 7 It is a schematic diagram of the welding scheme between the chip and the circuit board in an embodiment of the present application.

[0024] Figure 8 and Figure 9 It is a schematic diagram comparing the solder mask opening in the embodiment of the present application with the rectangular solder mask opening.

[0025] Figure 10 It is a schematic diagram of the shape and size of the solder mask opening and the solder pad in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0027] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0028] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0029] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0030] The display panel described in the embodiments of the present application can be used as a display backlight module to provide light with a specific color and brightness. For example, the LED chip in the display panel can be Mini-LED or Micro-LED. Hereinafter, the LED chip is referred to as a chip.

[0031] The display panel is also commonly referred to as a light board, which includes a circuit board and an LED chip. The circuit board in the embodiment of the present application can be, for example, a substrate formed by FR4, BT or glass. The surface of the circuit board is covered with a solder mask, which is composed of white ink or dry film, etc. It has a high reflectivity, thereby playing the role of insulation and light reflection. A window is provided on the solder mask, and the window is a notch etched on the solder mask. A solder pad is provided in the window, and the solder pad is used for welding between the chip and the circuit board. The solder pads are arranged in an array on the circuit board. A conductive circuit is provided on the circuit board and is covered by the solder mask. The conductive circuit is used to connect the solder pad and the circuit board.

[0032] The soldering method used in the embodiments of the present application is, for example, reflow soldering, which is commonly used in surface mounting technology (SMT). During the reflow soldering process, the mechanical and electrical connections between the chip electrodes and the pads are achieved by remelting the solder paste, such as solder paste, that has been pre-dispensed onto the pads.

[0033] Figure 1 A welding scheme between a chip and a circuit board is shown. Figure 1 As shown, the circuit board is covered with a solder mask layer 100, and a solder mask window 110 is provided in the solder mask layer 100, which is also referred to as the window 110 below. Two pads 111 are symmetrically provided in the window 110, and the pads 111 are used for welding between the chip 200 and the circuit board. Among them, the shape of the window 110 is rectangular, and the shape of the pad 111 is trapezoidal. Figure 2 As shown, the two electrodes of the chip 200 , namely the P region and the N region, are respectively welded to two welding pads 111 symmetrically arranged in the window 110 .

[0034] like Figure 1 and Figure 2 As shown, the portion of the window 110 other than the area where the pad 111 is located is a hollow area 112. The hollow area 112 is not covered with the solder mask 100. The color of the hollow area 112 is similar to the color of the circuit board, usually darker, and its reflectivity is much lower than the reflectivity of the solder mask 100 formed by white ink or dry film, which may affect the reflectivity and luminous effect of the display panel.

[0035] Figures 3 to 5 Another welding solution between the chip and the circuit board is shown. Figure 3 As shown, the circuit board is covered with a solder mask layer 300, and a solder mask window 310 is provided in the solder mask layer 300, which is also referred to as the window 310 below. Two pads 311 are symmetrically provided in the window 310, and the pads 311 are used for welding between the chip 200 and the circuit board. Among them, the shape of the window 310 is rectangular, and the shape of the pad 311 is also rectangular. Figure 4 As shown, the two circuits of the chip 200, namely the P region and the N region, are respectively soldered to the two solder pads 311 symmetrically arranged in the window 310. The portion of the window 310 other than the area where the solder pads 311 are located is a hollow area 312. Figure 1 and Figure 2 The design of the trapezoidal pad and rectangular window shown in FIG, when the rectangular pad and rectangular window design are adopted, the area of ​​the hollow area 312 is smaller, which can reduce its impact on the reflectivity and luminous effect of the display panel. Figure 5 As shown, when a rectangular pad and a rectangular window are used, the chip 200 is easily offset to one side during the welding process, and the offset direction is uncontrollable, thereby affecting the die bonding yield and the luminous effect of the display panel.

[0036] To this end, an embodiment of the present application provides a welding solution that uses a trapezoidal pad and a window shape that is "wide at both ends and narrow in the middle", which can improve the welding reliability between the chip and the circuit board in the display panel and improve the reflectivity of the display panel.

[0037] Figure 6 and Figure 7 The soldering scheme between the chip and the circuit board of the embodiment of the present application is shown as follows: Figure 6The display panel shown includes a circuit board (not shown in the figure) and a solder mask 400 covering the surface of the circuit board. The solder mask 400 is provided with a window 410, wherein along the length direction X of the window 410, the size of the window 410 in the width direction Y gradually decreases from the edge to the middle area, thereby forming a "wide at both ends and narrow in the middle" shape.

[0038] The display panel further includes a pad group, which is disposed in the window 410 and includes two trapezoidal pads 411 symmetrically disposed along the longitudinal direction X.

[0039] like Figure 7 As shown, the display panel further includes a chip 200 , which is soldered to the circuit board via two trapezoidal solder pads 411 in the solder pad group.

[0040] The trapezoid described in the embodiments of the present application can be, for example, an isosceles trapezoid, thereby improving the soldering performance between the pad 411 and the chip 200. The two parallel sides of the trapezoid are the bases, with the longer base being the lower base and the shorter base being the upper base. The other two sides are the waists of the trapezoid. When the two waists are equal, an isosceles trapezoid is formed.

[0041] It can be seen that the present application adopts a trapezoidal pad and a window shape of "wide at both ends and narrow in the middle". On the one hand, since the trapezoidal pad 411 is used to realize the welding of the chip 200 and the circuit board, the offset of the chip 200 in the width direction Y can be reduced during the welding process. For example, Figure 7 As shown, two electrodes, namely the P region and the N region, are provided on the side of the chip 200 facing the circuit board. The two electrodes are respectively welded to two trapezoidal pads 411, and in the width direction Y, the size of the chip 200 is the same as the width of the upper bottom of the trapezoidal pad 411. In this way, during the welding process, when the trapezoidal pad 411 is still in liquid solder and has not completely solidified, the chip 200 is located on the surface of the liquid solder, and the two end points of the upper bottom of the trapezoidal pad 411 become the boundaries of the liquid solder, so that the chip 200 cannot continue to translate in the width direction Y, thereby limiting the chip 200 in the width direction Y, reducing the offset of the chip 200, and improving the welding reliability between the chip 200 and the circuit board.

[0042] On the other hand, since the shape of the window 410 is "wide at both ends and narrow in the middle", the area of ​​the hollow region 412 in the window 410 except the trapezoidal pad 411 is as small as possible, thereby improving the reflectivity of the display panel. Figure 8 and Figure 9 As shown, the window shape of the embodiment of the present application is Figure 1 and Figure 2Compared to the rectangular opening 110 shown in FIG, the area of ​​the hollow region 412 is significantly reduced because the dimension in the width direction Y gradually narrows toward the middle region. Calculation shows that the reduced portion 413 accounts for approximately 55% of the area of ​​the hollow region 412, which is equivalent to the area of ​​the circuit board exposed within the solder mask opening. The coverage area of ​​the solder mask layer 400 is increased by 55%, effectively improving the reflectivity of the display panel.

[0043] It can be understood that the size of the chip 200 mentioned above is the same as the width of the upper bottom of the trapezoidal pad 411, which means that the size of the chip 200 is basically or approximately equal to the width of the upper bottom of the trapezoidal pad 411. For example, in the width direction Y, the width dimension of the chip 200 can be equal to the width dimension of the upper bottom of the trapezoidal pad 411, and the width dimension of the chip 200 can also be slightly smaller than the width dimension of the upper bottom of the trapezoidal pad 411.

[0044] The bottom of the trapezoidal pad 411 can be located, for example, at an edge of the window 410 parallel to the width direction Y, thereby further reducing the area of ​​the hollow region 412. The bottom of the trapezoidal pad 411 is fixedly connected to the inner wall of the window 410 and is connected to the conductive traces within the circuit board at the bottom.

[0045] In some embodiments, the area occupied by the two trapezoidal pads 411 within the window 410 is greater than the area occupied by the hollow region 412 within the window 410 excluding the two trapezoidal pads 411. Thus, compared to the scheme of trapezoidal pads 411 and rectangular window 410, the area of ​​the hollow region 412 can be significantly reduced, such that the area of ​​the hollow region 412 within the window 410 is smaller than the area occupied by the trapezoidal pads 411.

[0046] The following, combined Figure 10 Specifically describe the shape and size of the window 410. Optionally, as Figure 10 As shown, the window 410 includes two trapezoidal areas symmetrically arranged along the length direction X, and a middle area between the two trapezoidal areas, and the trapezoidal areas are used to set the pads.

[0047] like Figure 10As shown, the middle area can be set to a rectangle, the lower base of the trapezoidal area is located at the edge of the window 410 parallel to the width direction Y, the size of the lower base of the trapezoidal area is W1, and the size of the upper base of the trapezoidal area is the same as the size of the middle area in the width direction Y, both of which are W2. The sizes of the upper and lower bases of the trapezoidal pad 411 are L1 and L2, respectively. Preferably, the size of the lower base of the trapezoidal pad 411 can be set to 1.5 to 2 times the size of the upper base. In this way, the area of ​​the trapezoidal pad 411 can be increased, so that the solder can be fully spread, and the soldering adhesion of the chip 200 can be increased. The size W1 can be adjusted based on the size L2, and the corresponding window processing tolerance can be reserved. The size W2 can be adjusted based on the size L2, and the corresponding window processing tolerance can be reserved.

[0048] Since the window 410 includes two trapezoidal areas symmetrically arranged along the length direction X and an intermediate area located between the two trapezoidal areas, the shape of the window 410 matches the shape of the trapezoidal pad 411, so that the area of ​​the hollow area 412 in the window 410 except the trapezoidal pad 411 is as small as possible, thereby improving the reflectivity of the display panel.

[0049] Alternatively, as Figure 10 As shown, the waist of the trapezoidal region of the window 410 is parallel to the waist of the trapezoidal pad 411. Furthermore, to take into account actual process conditions, a gap may be provided between the waist of the trapezoidal region and the waist of the trapezoidal pad 411, with the dimension of this gap being G. This can further reduce the area of ​​the hollow region 412, thereby improving the reflectivity of the display panel. The dimension G can be reserved based on the window processing tolerance.

[0050] Based on the above description, the trapezoidal pad 411 and the "wide at both ends and narrow in the middle" window-shaped welding solution provided by this application can significantly improve the welding effect of the chip 200 during the welding process, so that the offset of the chip 200 in the width direction Y during the welding process is basically zero, solving the problems of empty solder joints or cold solder joints caused by the offset of the chip 200. At the same time, the solder mask window 410 has a small hollow area 412, which reduces the impact on the reflectivity of the display panel.

[0051] An embodiment of the present application further provides a backlight display module, comprising the display panel described in any of the above embodiments.

[0052] In the embodiments of the present application, the size of the serial numbers of each step does not mean the order of execution. The order of execution of each step should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0053] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0054] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A display panel, characterized in that: include: Circuit board; A solder mask layer covers the surface of the circuit board, wherein the solder mask layer is provided with a window, wherein along the length direction of the window, the width direction of the window gradually decreases from the edge to the middle area; a pad group disposed in the window, the pad group comprising two trapezoidal pads symmetrically disposed along the length direction; and The chip is welded to the circuit board through the welding pad group.

2. The display panel according to claim 1, wherein: The window includes two trapezoidal areas symmetrically arranged along the length direction, and the middle area located between the two trapezoidal areas, and the trapezoidal areas are used to set the pad.

3. The display panel according to claim 2, wherein: The middle area is rectangular, the lower base of the trapezoidal area is located at the edge of the window, and the upper base of the trapezoidal area has the same size as the middle area in the width direction.

4. The display panel according to claim 2 or 3, wherein: The waist of the trapezoidal region is parallel to the waist of the trapezoidal pad, and a gap is provided between the waist of the trapezoidal region and the waist of the trapezoidal pad.

5. The display panel according to any one of claims 1 to 3, characterized in that The area occupied by the two trapezoidal pads in the window is greater than the area occupied by the hollow area in the window except the two trapezoidal pads.

6. The display panel according to any one of claims 1 to 3, characterized in that: The shape of the trapezoidal pad is an isosceles trapezoid, and the lower base of the trapezoidal pad is located at the edge of the window.

7. The display panel according to any one of claims 1 to 3, characterized in that: Two electrodes are provided on a side of the chip facing the circuit board. The two electrodes are respectively welded to the two trapezoidal pads. The dimension of the chip in the width direction is the same as the width of the upper bottom of the trapezoidal pad.

8. The display panel according to any one of claims 1 to 3, characterized in that: The size of the lower base of the trapezoidal pad is 1.5 to 2 times the size of the upper base.

9. The display panel according to any one of claims 1 to 3, characterized in that: The chip is a mini light emitting diode or a micro light emitting diode.

10. A backlight display module, characterized in that: The device comprises a display panel according to any one of claims 1 to 9.

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