Circuit board, light-emitting module and display device

Abstract

The utility model discloses a circuit board, a light-emitting module and a display device. The circuit board comprises a main board body and a bonding pad, a sinking groove is formed in the surface of the main board body, the sinking groove comprises a first sinking section and a second sinking section which are horizontally arranged and connected, and the sinking depth of the second sinking section is larger than that of the first sinking section; and the bonding pad is in one-to-one correspondence with the sinking grooves and comprises a first welding part and a second welding part which are connected, the first welding part is embedded in the first sinking section, and the second welding part is embedded in the second sinking section. According to the technical scheme, the contact area of the bonding pad and the main board body of the circuit board can be increased, the fixed connection capability of the bonding pad is improved, the looseness of the welding spot position of the bonding pad is reduced, the more stable connection of the light-emitting device is ensured, and the situation that the light-emitting device falls off is reduced.

Description

Technical Field

[0001] The present application belongs to the field of display technology, and specifically relates to a circuit board, a light-emitting module and a display device. Background Art

[0002] LED (Light-Emitting Diode) is usually installed on a circuit board using SMT (Surface Mounted Technology). The circuit board is provided with solder pads, and the LED pins and the solder pads are connected through solder joints, which are formed by melted solder paste. However, after being impacted or hit, the solder joints are easily loosened, causing the LED to fall off. Utility Model Content

[0003] The purpose of the present application is to provide a circuit board, a light-emitting module and a display device, which can effectively improve the fixed connection ability of the pad, reduce the problem of loose solder joints, and reduce the falling off of the light-emitting device.

[0004] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0005] According to one aspect of an embodiment of the present application, the present application provides a circuit board, the circuit board comprising:

[0006] A main board body, wherein a sinking groove is provided on the surface of the main board body, wherein the sinking groove comprises a first sinking section and a second sinking section which are arranged horizontally and connected, and the sinking depth of the second sinking section is greater than the sinking depth of the first sinking section;

[0007] The welding pad corresponds to the sink groove one by one, and the welding pad includes a first welding part and a second welding part connected to each other, the first welding part is embedded in the first sinking section, and the second welding part is embedded in the second sinking section.

[0008] In one aspect, the second welding portion includes a welding bottom wall and a welding side wall, the welding bottom wall is formed on the bottom wall of the second sinking section, and the thickness of the welding bottom wall is less than the sinking depth of the second sinking section, and the welding side wall is formed on the side wall of the second sinking section and is arranged around the welding bottom wall to form a welding groove with the welding bottom wall.

[0009] In one aspect, the thickness of the first welding portion is equal to the sinking depth of the first sinking section.

[0010] In one aspect, the length of the first welding portion in the horizontal arrangement direction is greater than the length of the second welding portion in the horizontal arrangement direction.

[0011] In one aspect, the sinking depth of the first sinking section is H1, and the sinking depth of the second sinking section is H2, then: 0.1

[0012] The pad comprises a copper foil layer, a nickel-plated layer and a gold-plated layer which are sequentially stacked from bottom to top.

[0013] In one aspect, the main body is provided with at least one sinking groove group, the sinking groove group includes two sinking grooves arranged at intervals, which are defined as a first sinking groove and a second sinking groove respectively;

[0014] The circuit board includes at least one pad group, the pad group includes two pads arranged at intervals, which are defined as a first pad and a second pad, respectively, the first pad is matched with the first sink, and the second pad is matched with the second sink;

[0015] Wherein, the second sinking section of the first pad is arranged adjacent to the second sinking section of the second pad.

[0016] In addition, in order to solve the above problems, the present application also provides a light-emitting module, which includes a light-emitting device and the circuit board mentioned above, the first pin of the light-emitting device is connected to the first solder pad through a first solder point, and the second pin of the light-emitting device is connected to the second solder pad through a second solder point.

[0017] In one aspect, the light emitting module further includes soldering paste, and the soldering paste is disposed on the outer surfaces of the first solder joint and the second solder joint, and extends to cover the first pin and the second pin.

[0018] In one aspect, the flux paste fills the interval gap between the first solder joint and the second solder joint.

[0019] In addition, in order to solve the above-mentioned problem, the present application also provides a display device, including a housing and the light-emitting module mentioned above, wherein the light-emitting module is installed in the housing.

[0020] In the present application, a sinking groove is provided on the main board body, and the pad is provided in the sinking groove to increase the contact area between the pad and the main board body. Moreover, the sinking groove also includes a first sinking section and a second sinking section that are connected. Since the sinking depth of the second sinking section is greater than the sinking depth of the first sinking section, the inner wall area of ​​the second sinking section is larger. When the second welding portion of the pad is provided in the second sinking section, the contact area between the pad and the main board body can be further increased, and then a fixed connection can be performed at more positions, thereby improving the connection and fixing force between the pad and the main board body. The connection stability of the pad is improved, and the light-emitting device synchronously provided on the pad is also more secure. Even if the circuit board is hit, the pad is not easy to loosen, thereby reducing the possibility of the light-emitting device falling off.​

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 The main board structure diagram of the circuit board of the present application is schematically shown.

[0024] Figure 2 The schematic diagram shows the structure of the main board body and the pads in the circuit board of the present application.

[0025] Figure 3 The application is schematically shown Figure 2 A structural diagram showing the enlarged details of the location of the second sinking section.

[0026] Figure 4 The schematic diagram shows the structure of the light emitting device in the present application arranged on the circuit board.

[0027] Figure 5 The schematic diagram of the structure of setting flux glue on the display device in the present application is shown schematically.

[0028] Figure 6 The cross-sectional structure diagram of the light-emitting device in the present application is schematically shown.

[0029] The following are the descriptions of the reference numerals:

[0030] 100, main board body; 200, solder pad; 300, light emitting device; 400, solder layer; 500, solder paste; 600, spacing gap; 700, solder resist layer;

[0031] 110, sinking groove; 111, first sinking section; 112, second sinking section; 201, first welding part; 202, second welding part; 203, welding groove; 210, copper foil layer; 220, nickel-plated layer; 230, gold-plated layer; 310, light-emitting chip; 320, first pin; 330, second pin; 340, packaging layer; 410, first solder joint; 420, second solder joint. DETAILED DESCRIPTION

[0032] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0033] See also Figures 1 to 4 As shown, the present application provides a circuit board, the circuit board includes: a main board body 100 and a pad 200, the main board body 100 is provided with a sink 110, the pad 200 is arranged in the sink 110, and the pad 200 is used to connect the light-emitting device 300; a circuit layer is provided in the main board body 100, and the circuit layer is used to connect the pad 200 and supply power to the pad 200. Usually, the circuit layer is a copper layer, and the signal is transmitted through the copper layer. For example, the signal is transmitted to the pad 200 through the copper layer, and then transmitted to the light-emitting device 300 through the pad 200, so as to ensure that the light-emitting device 300 can be normally lit.

[0034] The pad 200 is embedded in the sink 110 , and the sink 110 can play a certain role in fixing the pad 200 , so that the position of the pad 200 can be more firmly secured.

[0035] In addition, the main board 100 is a glass fiber board or a glass fiber composite board, which is usually composed of glass fiber material and a high heat-resistant composite material, does not contain any harmful components to the human body, has high mechanical and dielectric properties, good heat resistance and moisture resistance, and good processability.

[0036] The sinking groove 110 includes a first sinking section 111 and a second sinking section 112 which are arranged horizontally and connected. The sinking depth of the second sinking section 112 is greater than the sinking depth of the first sinking section 111. The pad 200 corresponds to the sinking groove 110 one by one. The pad 200 includes a first welding portion 201 and a second welding portion 202 which are connected. The first welding portion 201 is embedded in the first sinking section 111, and the second welding portion 202 is embedded in the second sinking section 112. The first sinking section 111 and the second sinking section 112 are interconnected. When the pad 200 is set, the structure of the pad 200 can be extended along the inner wall surface of the sinking groove 110, for example, extending from the first sinking section 111 to the second sinking section 112, and spreading over the entire inner wall surface of the second sinking section 112.

[0037] In this embodiment, a sinking groove 110 is provided on the main body 100, and the pad 200 is provided in the sinking groove 110, which can increase the contact area between the pad 200 and the main body 100. Moreover, the sinking groove 110 also includes a first sinking section 111 and a second sinking section 112 that are connected. Since the sinking depth of the second sinking section 112 is greater than the sinking depth of the first sinking section 111, that is to say, the inner wall area of ​​the second sinking section 112 is larger. When the second welding portion 202 of the pad 200 is provided in the second sinking section 112, the contact area between the pad 200 and the main body 100 can be further increased, and then fixed connection can be performed at more positions, thereby improving the connection and fixing force between the pad 200 and the main body 100. The connection stability of the pad 200 is improved, and the light-emitting device 300 synchronously provided on the pad 200 is also more secure. Even if the circuit board is hit, the pad 200 is not easy to loosen, thereby reducing the situation where the light-emitting device 300 falls off.

[0038] It should be further explained that the inner wall surface of the sinking groove 110 includes a bottom wall and a side wall. The second welding portion 202 includes a welding bottom wall and a welding side wall, the welding bottom wall is formed on the bottom wall of the second sinking section 112, and the thickness of the welding bottom wall is less than the sinking depth of the second sinking section 112, and the welding side wall is formed on the side wall of the second sinking section 112 and is arranged around the welding bottom wall, and the welding side wall is used to form a welding groove 203 with the welding bottom wall.

[0039] By providing the welding groove 203, not only the inner wall surface of the sink 110 can be increased, but also the volume of the sink 110 can be increased, thereby enabling the sink 110 to accommodate more welding materials, for example, more solder paste can be accommodated in the welding groove 203. When more solder paste is provided, the wrapping effect of the solder paste is also better, which can improve the pin fixing effect of the light emitting device 300.

[0040] When manufacturing a circuit board, materials are generally prepared first. The copper plate and the main board 100 are pressed together. A protective aluminum plate is covered on the copper plate, and then four positioning holes are punched at the four corners of the copper plate. Then, according to the designed circuit diagram, holes are drilled on the copper plate, that is, sink grooves 110 are set. After drilling the sink grooves 110, the copper plate needs to be cleaned to avoid residues left during drilling.

[0041] Then the copper traces are engraved. First, a layer of dry film is covered on the copper plate. Then a photomask is printed according to the designed circuit diagram and the photomask is covered on the copper plate. Then the circuit board is placed in a UV light machine. When irradiated with UV light, the dry film in the originally black area will solidify. Then etching is performed. The circuit board is placed in an alkaline solution at 60-120 degrees Celsius. The exposed copper will be dissolved or etched away, so that the remaining copper lines are copper traces.

[0042] In addition, in order to prevent copper from oxidation or contact with dust, a layer of solder resist ink, generally green or black, needs to be applied to the circuit board. These sinks 110 on the circuit board need to be installed with electronic components, so these holes need to be exposed. To this end, the printed photomask is covered on the copper plate, and the photomask can just cover the sink 110, and then irradiated with light. The ink exposed to the light will solidify, while the black areas will not solidify if not irradiated. Then the sink 110 on the circuit board can be exposed using solder resist development technology. Then screen printing is used to print some component logos and symbols on the circuit board, such as setting the light-emitting device 300 on the pad 200. Pretreatment and testing are then performed, including cleaning and inspection, to ensure that the circuit board functions properly.

[0043] In the present application, the thickness of the first welding portion 201 is equal to the sinking depth of the first sinking section 111. In other words, the upper surface of the first welding portion 201 is flush with the upper surface of the main board body 100. The first welding portion 201 is reduced from protruding from the upper surface of the main board body 100, so that the first welding portion 201 can be placed just in the first sinking section 111, making the surface of the circuit board more flat.

[0044] Furthermore, the length of the first soldering portion 201 in the horizontal arrangement direction is greater than the length of the second soldering portion 202 in the horizontal arrangement direction. The horizontal arrangement direction refers to the direction from the first soldering portion 201 to the second soldering portion 202. Generally, the first soldering portion 201 mainly corresponds to the pin arrangement of the light-emitting device 300. The contact area between the first soldering portion 201 and the pin is large, and the first soldering portion 201 is the main structure for fixing the light-emitting device 300. By increasing the length of the first soldering portion 201, the fixing force of the soldering pad 200 on the light-emitting device 300 can be increased, and the stability of the light-emitting device 300 can be improved.

[0045] In order to improve the fixing force of the groove 110 to the solder pad 200, the sinking depth from the bottom of the first sinking section 111 to the upper surface of the main board body 100 is defined as H1, and the sinking depth from the bottom of the second sinking section 112 to the upper surface of the main board body 100 is defined as H2, which satisfies: 0.1

[0046] This embodiment specifically discloses the proportional relationship between H1 and H2. It is understood that the proportional relationship between H1 / H2 can be greater than 0.10 or less than 0.60. Specifically, the proportional multiple can be 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50 or 0.55, etc. By limiting the proportional relationship, it is ensured that the depth of the second sinking section 112 is deep enough to meet the fixing requirements of the pad 200.

[0047] ​Furthermore, the numerical ranges of the two sinking depths can be: 12um

[0048] Among them, H1 can be greater than 12um or less than 47um, but the selection range of H1 is not limited thereto. Specifically, H1 can be 15um, 20um, 25um, 30um, 35um, 40um or 45um. Similarly, H2 can be greater than 100um or less than 300um. For example, H2 can also be 150um, 200um or 250um, etc.

[0049] In another embodiment of the present application, the main body 100 is provided with at least one group of sink grooves 110, the sink grooves 110 group includes two sink grooves 110 arranged at intervals, respectively defined as a first sink groove and a second sink groove; one sink groove 110 group is provided corresponding to one light emitting device 300. The circuit board includes at least one group of pads 200, the pads 200 group includes two pads 200 arranged at intervals, respectively defined as a first pad 200 and a second pad 200, the first pad 200 is matched with the first sink groove, and the second pad 200 is matched with the second sink groove; wherein the second sinking section 112 of the first pad 200 is arranged adjacent to the second sinking section 112 of the second pad 200.

[0050] For example, the light emitting device 300 is provided with two pins, namely a first pin 320 and a second pin 330. The first pin 320 may be provided corresponding to the first recess, and the second pin 330 may be provided corresponding to the second recess.

[0051] In another example, the number of pins of the light emitting device 300 is sometimes not limited to two. For example, if there are four pins, there may be four corresponding pads 200. The number of pads 200 and the number of sinks 110 correspond to the number of pins.

[0052] In addition, the two second sinking sections 112 being arranged adjacently can be understood as the two second sinking sections 112 being arranged oppositely. This ensures that the second sinking sections 112 are located directly below the light emitting device 300, which helps maintain the center of gravity of the light emitting device 300 stable and avoids the situation of unstable center of gravity and left and right tilting.

[0053] In addition, the second sinking section 112 can also be arranged in the middle of the first sinking section 111. Of course, it is also possible that the two second sinking sections 112 are arranged far away from each other.

[0054] ​Furthermore, the number of the second sinking sections 112 is not limited to one. Multiple second sinking sections 112 can be set in one sinking groove 110. The multiple second sinking sections 112 are spaced apart and can be set at multiple angles or directions of the first sinking section 111. This can increase the contact angle between the solder pad 200 and the main board body 100 in multiple directions, further increasing the adhesion.

[0055] Furthermore, the pad 200 includes a copper foil layer 210 , a nickel-plated layer 220 and a gold-plated layer 230 , and the copper foil layer 210 , the nickel-plated layer 220 and the gold-plated layer 230 are stacked in sequence from bottom to top.

[0056] The copper foil layer 210 is a basic part of the circuit in the circuit board. On the one hand, it is used to transmit electrical signals and conduct heat. It can transmit electrical signals to the light-emitting device 300 and dissipate the heat generated by the light-emitting device 300 as soon as possible. On the other hand, it is also used to mechanically connect and fix the pad 200 to the main board 100. The nickel-plated layer 220 is plated on the copper foil layer 210 by chemical plating. The nickel-plated layer 220 is a metal plating layer and can also be conductive. It is used to solder with the pins of the light-emitting device 300 through solder paste. The gold-plated layer 230 is plated on the nickel-plated layer 220 by chemical plating, which is used to improve the welding performance of the nickel-plated layer 220 and improve the welding effect with the solder paste. The nickel-plated layer 220 is arranged on the copper foil layer 210 and can also prevent the problem of excessive reaction between the metal tin and copper in the solder paste solder, which leads to a decrease in the strength of the solder joint.

[0057] In addition, the nickel-plated layer 220 itself is easily oxidized when it encounters air. The arrangement of the gold-plated layer 230 can also prevent the nickel-plated layer 220 from being oxidized, thereby providing a certain degree of protection for the nickel-plated layer 220 .

[0058] In addition to the above methods, the present application can also plate OSP (Organic solderability preservative) on the copper layer. The organic solderability preservative is an organic coating used to prevent copper from oxidizing before soldering, that is, to protect the solderability of the pad 200 from being damaged. It can also be a surface treatment method such as tin plating on the copper layer. Tin plating on the copper layer deposits a layer of bright metal tin on the surface of the copper layer, which can increase the solderability of the copper layer and has an anti-oxidation purpose.

[0059] The light emitting device 300 refers to an LED lamp bead, and a plurality of solder pads 200 are usually provided on the main board body 100, and the LED lamp bead is soldered on the solder pads 200. The light emitting device 300 is fixed by the solder pads 200.

[0060] Among them, the light-emitting device 300 can be an SMD lamp bead (Surface Mounted Devices), a Mini LED (Mini Light Emitting Diode Display), or a Micro LED (MicroLight Emitting Diode Display).

[0061] See also Figure 4 and Figure 5 As shown, the present application also provides a light-emitting module, which includes a light-emitting device 300, a welding layer 400 and a circuit board as described above, wherein the welding layer 400 includes a first welding point 410 and a second welding point 420. The first pin 320 of the light-emitting device 300 is connected to the first solder pad 200 through the first solder point 410, and the second pin 330 of the light-emitting device 300 is connected to the second solder pad 200 through the second solder point 420.

[0062] The welding layer 400 is disposed between the pins of the light emitting device 300 and the pads 200. The welding layer 400 is mainly used to complete the welding and fixing of the pins. Generally, the welding layer 400 is solder. During welding, the solder is in a molten state, and the pins of the light emitting device 300 are aligned and set on the pads 200. After the solder cools and solidifies, the light emitting device 300 is fixed on the pads 200.

[0063] In another embodiment of the present application, the light-emitting module further includes a soldering glue 500, which is disposed on the outer surface of the first solder joint 410 and the second solder joint 420 and extends to cover the first pin 320 and the second pin 330. The soldering glue 500 is not easy to volatilize during the cooling process of the solder, but is retained at the pin position of the light-emitting device 300. The soldering glue 500 has a certain viscosity and can fix the light-emitting device 300 on the pad 200, further improving the fixing effect and improving the welding strength.

[0064] In the related art of the present application, there is also a situation where the light emitting device 300 is not installed stably enough, that is, it is uneven on the left and right sides. This will cause the light emitting device 300 to have yin and yang colors, that is, the light emitting device 300 is tilted, causing the light emitting surface of the light emitting device 300 to face the side, and when the user views the display device from the front, the brightness of each light emitting device 300 is different.

[0065] For this purpose, solder paste 500 is added to the solder paste. The solder paste 500 has a certain fluidity, and during the flow process, the solder paste 500 forms a certain surface tension. Under the pulling action of the surface tension, the left and right ends of the light-emitting device 300 can be balanced in force, thereby maintaining the horizontal state of the light-emitting device 300.

[0066] Furthermore, a soldering glue 500 is provided at each pin position of the light emitting device 300. If the light emitting device 300 is deflected to the left or right, the soldering glue 500 can extend on both sides, thereby applying force to the light emitting device 300 on the left and right sides, thereby flattening the left and right ends of the light emitting device 300. In other words, the soldering glue 500 in the present application also has a certain ability to correct the deformation of the light emitting device 300. When welding the light emitting device 300, the light emitting device 300 can be actively corrected to ensure the left and right balance of the light emitting device 300.

[0067] In another embodiment of the present application, a spacing gap 600 is formed between the lower surface of the light-emitting device 300 and the upper surface of the circuit board; the solder paste 500 is filled in the spacing gap 600 between the first solder joint 410 and the second solder joint 420. The solder paste 500 is filled in the spacing gap 600 by utilizing its fluidity and is bonded to the lower surface of the light-emitting device 300 and the upper surface of the circuit board. The solder paste 500 is filled in the spacing gap 600, and more positions of the light-emitting device 300 are connected to the circuit board through the solder paste 500. By providing the solder paste 500, the connection between the light-emitting device 300 and the circuit board is improved, and the light-emitting device 300 is further fixed on the circuit board more firmly.

[0068] It should be noted that the flux glue 500 is mixed in the solder paste. When the light-emitting device 300 is soldered and fixed, the fluidity of the solder is poor, while the flux glue 500 has a fluidity similar to that of glue. The flux glue 500 can be precipitated from the solder paste and actively flow to the spacing gap 600 and the surface of the pin, thereby filling the spacing gap 600 and covering the pin.

[0069] It should be noted that the solder paste of the present application is an epoxy resin solder paste. In addition to flux, the epoxy resin solder paste is also provided with epoxy resin and curing agent, thereby increasing the volume proportion of non-metallic materials, and sufficient non-metallic liquid materials can be filled into the spacing gap 600 during the welding process, making full use of the fluidity of non-metallic liquid materials. Among them, the epoxy resin is one or more mixtures of bisphenol A epoxy resin, bisphenol F epoxy resin and dicyclopentadiene-phenol epoxy resin. The curing agent is one or more mixtures of diethyltetramethylimidazole, dicyandiamide, and methyltetrahydrophthalic anhydride.

[0070] See also Figure 6 As shown, the light emitting device 300 further includes a light emitting chip 310 and an encapsulation layer 340, and the encapsulation layer 340 encapsulates the light emitting chip 310. A connecting wire is provided between the light emitting chip 310 and the first pin 320, and a connecting wire is provided between the light emitting chip 310 and the second pin 330. This ensures that the light emitting chip 310 can receive external electrical signals. The encapsulation layer 340 wraps the light emitting chip 310, and can protect the light emitting chip 310.

[0071] The role of the encapsulation layer 340 includes physical protection. The encapsulation layer 340 encapsulates the outer surface of the light emitting chip 310 to protect the light emitting chip 310 from the external environment, such as impurities, moisture, dust and humidity in the air, and protects the surface and connection wires of the light emitting chip 310. The encapsulation layer 340 can also match the thermal expansion coefficient of the light emitting chip 310 with the thermal expansion coefficient of the frame or circuit board, relieve stress caused by heat or external environmental changes, and reduce damage and failure of the light emitting chip 310.

[0072] The packaging layer 340 can also adapt to the size of the mounting by adjusting the size (such as changing the pitch) to simplify the mounting operation.

[0073] The packaging layer 340 is provided to facilitate the standardization of the light emitting chip 310. The size, shape, number of pins, spacing and length of the packaging are all standardized, which is convenient for processing and also convenient for commonality with production lines and production equipment, which helps to improve work efficiency.

[0074] In addition, the encapsulation layer 340 can also provide stable mechanical support for the light emitting chip 310 and other components to prevent damage caused by vibration, impact, temperature change and the like.

[0075] The present application provides a display device, including a housing and the above-mentioned light-emitting module, the light-emitting module is installed in the housing, and the housing protects the light-emitting module. The display device also includes a solder resist layer 700, which is arranged on the upper surface of the circuit board and is located between two adjacent sinks 110. The function of the solder resist layer 700 is to prevent the parts that should not be soldered from being connected by solder. In this embodiment, by setting the solder resist layer 700, it is possible to avoid the connection between two adjacent pads 200 to prevent a short circuit. When setting the solder, it is also possible to avoid the solder from sticking together, avoid the second pin 330 of the light-emitting device 300 and the first pin 320 from being directly connected, and avoid the occurrence of a short circuit.

[0076] In order to prevent copper from oxidation and contact with dust, a layer of solder mask ink, usually green or black, needs to be applied on the circuit board. At the same time, the position of the sink 110 needs to be exposed, and the printed photomask is covered on the copper plate, and the photomask can just cover all the holes. Then use light to irradiate. The green ink exposed to the light will solidify, while the black areas that are not exposed to the light will not solidify. Then, the solder mask development technology can be used to expose the sink 110 on the circuit board.

[0077] The solder paste is applied to the sink 110 by printing, and then the light emitting device 300 is installed on the solder paste. Then the circuit board is placed in a reflow soldering heating furnace, and the light emitting device 300 is soldered on the circuit board.

[0078] In the present application, the orthographic projection of the second sinking section 112 on the main body 100 is located within the orthographic projection range of the light emitting device 300 on the main body 100. Further, the second sinking section 112 can be arranged close to the center of the light emitting device 300, so that the middle position of the light emitting device 300 can be guaranteed to receive sufficient connection and fixing force, so that the center of gravity of the light emitting device 300 can be more stable, and the left and right deviation of the light emitting device 300 can be reduced.

[0079] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary technical means in the art that are not disclosed in the present application.

[0080] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A circuit board, characterized in that: The circuit board comprises: A main board body, wherein a sinking groove is provided on the surface of the main board body, wherein the sinking groove comprises a first sinking section and a second sinking section which are arranged horizontally and connected, and the sinking depth of the second sinking section is greater than the sinking depth of the first sinking section; The welding pad corresponds to the sink groove one by one, and the welding pad includes a first welding part and a second welding part connected to each other, the first welding part is embedded in the first sinking section, and the second welding part is embedded in the second sinking section.

2. The circuit board according to claim 1, characterized in that: The second welding portion includes a welding bottom wall and a welding side wall. The welding bottom wall is formed on the bottom wall of the second sinking section, and the thickness of the welding bottom wall is less than the sinking depth of the second sinking section. The welding side wall is formed on the side wall of the second sinking section and is arranged around the welding bottom wall to form a welding groove with the welding bottom wall.

3. The circuit board according to claim 1, characterized in that: The thickness of the first welding portion is equal to the sinking depth of the first sinking section.

4. The circuit board according to claim 3, characterized in that: The length of the first welding portion in the horizontal arrangement direction is greater than the length of the second welding portion in the horizontal arrangement direction.

5. The circuit board according to claim 1, characterized in that: The sinking depth of the first sinking section is H1, and the sinking depth of the second sinking section is H2, then: 0.1<H1 / H2<0.6; and / or; The pad comprises a copper foil layer, a nickel-plated layer and a gold-plated layer which are sequentially stacked from bottom to top.

6. The circuit board according to any one of claims 1 to 5, characterized in that: The main body is provided with at least one sinking groove group, and the sinking groove group includes two sinking grooves arranged at intervals, which are defined as a first sinking groove and a second sinking groove respectively; The circuit board includes at least one pad group, the pad group includes two pads arranged at intervals, which are defined as a first pad and a second pad, respectively, the first pad is matched with the first sink, and the second pad is matched with the second sink; Wherein, the second sinking section of the first pad is arranged adjacent to the second sinking section of the second pad.

7. A light emitting module, characterized in that: The light-emitting module comprises a light-emitting device and the circuit board described in claim 6, wherein the first pin of the light-emitting device is connected to the first pad via a first solder joint, and the second pin of the light-emitting device is connected to the second pad via a second solder joint.

8. The light emitting module according to claim 7, characterized in that: The light-emitting module further includes soldering paste, which is disposed on the outer surfaces of the first solder joint and the second solder joint and extends to cover the first pin and the second pin.

9. The light emitting module according to claim 8, characterized in that: The flux glue fills the interval gap between the first welding point and the second welding point.

10. A display device, characterized in that: The invention comprises a housing and the light-emitting module according to any one of claims 7 to 9, wherein the light-emitting module is installed in the housing.

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