Display Mini-LED lamp bead and LED display screen
By combining flip-chip and upright mounting designs and using conductive insulating solder layers, the airtightness and uneven screen issues of small-pitch LED devices are solved, resulting in better display effects and reliability.
Patent Information
- Application Number
- CN202422991984.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2034-12-04
AI Technical Summary
Existing small-pitch LED devices have airtightness issues, which allow moisture to enter and cause failure. Furthermore, the uneven chip arrangement leads to a noticeable uneven screen effect when viewed at close range, affecting the display quality.
The design employs a combination of flip-chip and conventional chip mounting, with chips of uniform height and symmetrically arranged on the substrate. They are fixed using conductive and insulating solder layers to increase airtightness, and protected by insulating areas and ink encapsulation to improve chip arrangement and airtightness.
It improves the airtightness of small-pitch LED devices, reduces the uneven screen phenomenon, and enhances display effect and reliability.
Smart Images
Figure CN223651118U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of surface mount LED devices, and in particular to a display Mini-LED lamp bead and an LED display screen. Background Technology
[0002] In natural environments, global and national climates vary greatly, so the requirements for small-pitch LED devices are very stringent. Air tightness has always been a common problem with existing small-pitch LED devices. In nature, moisture can easily enter the interior of small-pitch LED devices, causing them to malfunction, lose their light, or exhibit poor display quality such as "caterpillar" effects, affecting the viewing experience. Furthermore, on the client side, LED display beads are mounted in an array on the PCB surface to form the luminous surface of the complete display. As LED displays increasingly diversify in terms of definition and application scenarios, in the early stages, due to the greater viewing distance and the obstruction of the mask, it was difficult to detect visual differences caused by insufficient mounting precision. In recent years, as the pitch of LED screens has continued to decrease and the viewing distance has become increasingly closer, extremely high precision requirements have been placed on LED beads, printed circuit boards, and surface mount technology. The slight defects in the production and manufacturing process that cause the light-emitting surface to tilt become obvious when viewed up close, highlighting the problem of uneven lighting. That is, when viewed from the left side of the LED screen, that side shows a more obvious problem of dim or brighter light, while when viewed from the right side, the opposite is true, showing a more obvious problem of bright or dim light. In other words, the LED screen shows a significant brightness difference between the left and right sides. Utility Model Content
[0003] The technical problem to be solved by this utility model is to provide a display Mini-LED lamp bead and LED display screen, which can improve the airtightness of small-pitch LED devices and improve the problem of uneven lighting on the display screen.
[0004] To solve the above-mentioned technical problems, this utility model provides a display Mini-LED lamp bead, comprising:
[0005] The support includes a horizontally arranged base plate;
[0006] A light-emitting unit mounted on the bracket includes a first light-emitting chip for emitting red light and a second light-emitting chip for emitting colors other than red light. The first light-emitting chip is inverted on the bracket, and the second light-emitting chip is upright on the bracket.
[0007] The front circuit board disposed on the top of the substrate;
[0008] And a back circuit board disposed at the bottom of the substrate.
[0009] As an improvement to the above solution, the height of the first light-emitting chip is kept consistent with the height of the second light-emitting chip.
[0010] As an improvement to the above scheme, the first light-emitting chip and the second light-emitting chip in the light-emitting unit are arranged sequentially on the central axis of the substrate and are symmetrical about the center point, and the first light-emitting chip and the second light-emitting chip are arranged at equal intervals.
[0011] As an improvement to the above solution, the first light-emitting chips and / or the second light-emitting chips in the light-emitting unit are isolated from each other.
[0012] As an improvement to the above solution, the front circuit board includes a die-bonding area and a wire bonding area, with the first light-emitting chip and the second light-emitting chip respectively disposed in different die-bonding areas;
[0013] The bonding area includes a cathode bonding area and a common anode bonding area. The cathode bonding area and the die bonding area are correspondingly arranged, and the die bonding area and the bonding area are electrically connected by bonding wires.
[0014] As an improvement to the above solution, the front circuit board also includes a through hole penetrating the substrate;
[0015] The back circuit board includes a pin area, which is correspondingly arranged with the bonding wire area, and the pin area and the bonding wire area are electrically connected through the through-hole.
[0016] As an improvement to the above solution, the through-hole is located at the corner of the substrate, and the front circuit board is covered with ink.
[0017] As an improvement to the above solution, the front circuit board also includes an insulating area, which separates the die-bonding areas to prevent mutual conductivity, and at the same time separates the bonding wire areas to prevent mutual conductivity.
[0018] The light-emitting unit is fixed to the substrate by a solder layer. When fixing the first light-emitting chip, the solder layer is a conductive adhesive layer, and when fixing the second light-emitting chip, the solder layer is an insulating adhesive layer.
[0019] As an improvement to the above solution, the top and / or bottom of the substrate are provided with marking structures for positioning and identifying the polarity of the LED beads;
[0020] The substrate is covered with encapsulating adhesive for sealing and protecting the light-emitting unit.
[0021] The second aspect of this utility model provides an LED display screen, which includes the aforementioned display Mini-LED lamp beads.
[0022] Implementing this utility model has the following beneficial effects:
[0023] In this utility model, a display Mini-LED lamp bead includes a light-emitting unit mounted on the bracket. The light-emitting unit includes a first light-emitting chip for emitting red light and a second light-emitting chip for emitting other colors besides red light. The first light-emitting chip is flip-mounted on the bracket, and the second light-emitting chip is mounted upright on the bracket. This can improve the light-emitting angle and light-emitting efficiency of the first light-emitting chip, effectively improve the problem of uneven screen brightness, and enhance the airtightness of small-pitch LED devices. Attached Figure Description
[0024] Figure 1 A schematic diagram of the front structure of a Mini-LED lamp bead in the prior art;
[0025] Figure 2 This application shows a schematic diagram of the front circuit board structure of the Mini-LED lamp beads;
[0026] Figure 3 This application shows a schematic diagram of the front structure of a Mini-LED lamp bead;
[0027] Figure 4 This application shows a schematic diagram of the back structure of a Mini-LED lamp bead;
[0028] Figure 5 This application shows a cross-sectional structural diagram of a Mini-LED lamp bead.
[0029] Figure label:
[0030] 1-Substrate; 2-Light-emitting unit; 21-First light-emitting chip; 22-Second light-emitting chip; 3-Front-side circuit board; 31-Die bonding area; 32-Wire bonding area; 321-Cathode wire bonding area; 322-Common anode wire bonding area; 33-Through hole; 34-Insulating area; 35-Bonding wire; 36-Electroplated lead; 37-Ink; 4-Rear circuit board; 41-Pin area; 411-Cathode pin area; 412-Anode pin area; 5-Identification structure; 6-Encapsulating adhesive; 7-Solder layer. Detailed Implementation
[0031] To make the objectives, technical solutions and advantages of this utility model clearer, specific embodiments will be described in further detail below.
[0032] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0033] Existing small-pitch LED devices use a flat BT substrate as a support. The substrate 1 is a single-layer board dividing a front circuit board 3 and a back circuit board 4. The front circuit board 3 is used to bond the light-emitting chips and achieve electrical interconnection, while the back circuit board 4 is used for soldering to the LED display module PCB. The front and back circuits are connected and conductive through through-holes 33. For details, please refer to... Figure 1 The front circuit of the substrate 1 is divided into a die bonding area 31, a wire bonding area 32 and an insulating area 34. The first light-emitting chip 21, which is used to emit red light, is fixed on the red light die bonding area, and the second light-emitting chips, which are used to emit blue light, green light and other colored light, are fixed on the corresponding die bonding areas. After molding and cutting processes, they become LED beads that can emit RGB three primary color light.
[0034] However, in existing small-pitch LED devices, the adhesion between the encapsulating adhesive 6 and the electroplated leads 36 is poor, and the die-bonding area 31 is a single structure, making it easier for moisture to enter the LED chip. Furthermore, in conventional LED chip structures, the red, green, and blue light chips are arranged in a straight line, and the height of the first light-emitting chip 21 is higher than that of the second light-emitting chip 22. Generally, the first light-emitting chip 21 is twice the height of the second light-emitting chip 22. This means that the light emission angle of the second light-emitting chip 22 is blocked by the red light, resulting in an angle difference, which is one of the reasons for uneven lighting on the screen. At the same time, due to the structural reasons of the first and second light-emitting chips 21 and 22, multiple light-emitting chips cannot be placed in the center when arranged, resulting in uneven pixel spacing on the display screen, exacerbating the formation of uneven lighting.
[0035] In addition, the existing single-electrode first light-emitting chip 21 is fixed with silver paste, which is easily affected by moisture and may peel off. Furthermore, the chip push force is low and the reliability is poor. At the same time, the single-electrode chip of the first light-emitting chip 21 has a reduced chip area due to the chip electrode blocking on the surface chip.
[0036] To resolve the above issues, please refer to [link / reference]. Figures 2-4 The first aspect of this utility model provides a display Mini-LED lamp bead, comprising:
[0037] The bracket includes a horizontally arranged substrate 1, a light-emitting unit 2 mounted on the bracket, a front circuit board 3 disposed on the top of the substrate 1, and a back circuit board 4 disposed on the bottom of the substrate 1.
[0038] The light-emitting unit 2 includes a first light-emitting chip 21 for emitting red light and a second light-emitting chip 22 for emitting colors other than red light. Optionally, the second light-emitting chip 22 can be a blue light-emitting chip and / or a green light-emitting chip. The light-emitting unit 2 preferably includes three different colored light-emitting chips. For example, the light-emitting unit 2 includes a first light-emitting chip 21 for emitting red light, a light-emitting chip for emitting blue light, and a light-emitting chip for emitting green light, and will be described in detail using this example. The light-emitting chips in the light-emitting unit 2 are arranged in a straight line along the longitudinal direction of the substrate 1. The light-emitting chip for emitting blue light, the light-emitting chip for emitting green light, and the first light-emitting chip 21 for emitting red light are arranged sequentially along the longitudinal direction of the substrate 1, with the first light-emitting chip 21 for emitting red light located near the edge of the substrate 1.
[0039] It should be noted that the material of the substrate 1 includes, but is not limited to, bismaleimide-triazine resin (BT resin).
[0040] Understandably, the different raw materials used to manufacture the first light-emitting chip 21 and the second light-emitting chip 22 result in different refractive indices, which in turn leads to different structures. Consequently, the height of the first light-emitting chip 21 is higher than that of the second light-emitting chip 22 during die bonding. Therefore, the first light-emitting chip 21 is flip-mounted on the support, while the second light-emitting chip 22 is mounted upright on the support. That is, the chip emitting blue light and the chip emitting green light are mounted upright on the support. By flip-mounting the first light-emitting chip 21 onto the substrate 1, the light-emitting area of the chip is increased due to the electrodes of the first light-emitting chip 21, resulting in higher brightness. At the same time, the height of the flip-mounted first light-emitting chip 21 is the same as the height of the upright-mounted second light-emitting chip 22, which does not affect the luminous efficiency of the second light-emitting chip 22 and does not cause the problem of light emission angle difference, effectively improving the problem of uneven screen brightness.
[0041] Furthermore, the height of the first light-emitting chip 21 is consistent with the height of the second light-emitting chip 22. This not only ensures the brightness of the first light-emitting chip 21, but also solves the problem of the first light-emitting chip 21 blocking the light-emitting angle of the second light-emitting chip 22, thus overcoming the phenomenon of uneven screen brightness caused by the difference in the light-emitting angles of different chips.
[0042] Furthermore, the first light-emitting chip 21 and the second light-emitting chip 22 in the light-emitting unit 2 are arranged sequentially and symmetrically about the center point on the central axis of the substrate 1, and the first light-emitting chip 21 and the second light-emitting chip 22 are arranged at equal intervals, so that the light-emitting unit 2 is centrally located on the substrate 1, which facilitates uniform light distribution, makes the pixel spacing in the display screen equal, and further improves the problem of uneven lighting on the display screen. It is understood that the shape of the substrate 1 can be rectangular, square, circular, etc. For example, the substrate 1 is rectangular; please refer to [link to relevant documentation]. Figure 3 The second light-emitting chip 22 and the first light-emitting chip 21, which are used to emit blue light and green light, are arranged equidistantly along the longitudinal direction of the substrate 1 and are located on the longitudinal central axis of the substrate 1. The center point of the green light-emitting chip located in the middle coincides with the intersection of the transverse center line and the longitudinal center line of the substrate 1 (the center point of the substrate 1).
[0043] Furthermore, the first light-emitting chips 21 and / or the second light-emitting chips 22 in the light-emitting unit 2 are isolated from each other. When moisture enters the interior of the light-emitting unit 2, it needs to enter through different channels, which prolongs the penetration path of the moisture and thus improves the airtightness of the Mini-LED LED beads. At the same time, the setting of electroplated leads 36 is avoided, overcoming the problem of poor adhesion between the encapsulating adhesive 6 and the electroplated leads 36, reducing the channels for moisture to enter the interior of the LED beads, and further improving the airtightness of the Mini-LED LED beads.
[0044] Please see Figure 2 The front circuit board 3 includes a die-bonding area 31 and a wire bonding area 32. The first light-emitting chip 21 and the second light-emitting chip 22 are respectively disposed in different die-bonding areas 31. That is, the die-bonding area 31 includes a first die-bonding area for fixing the first light-emitting chip 21 and a second die-bonding area for fixing the second light-emitting chip 22. When the second light-emitting chip 22 includes a light-emitting chip for emitting blue light and a light-emitting chip for fixing a light-emitting chip for emitting green light, the second die-bonding area includes a plurality of second die-bonding sub-areas for fixing the light-emitting chip for emitting blue light and the light-emitting chip for emitting green light, respectively. It can be seen that the number of die-bonding areas 31 is determined according to the number of light-emitting chips, and only one light-emitting chip is fixed in each die-bonding area 31.
[0045] Understandably, the first light-emitting chip 21 and the second light-emitting chip 22 are fixed in different ways. Therefore, the first die-bonding area used to fix the first light-emitting chip 21 needs to be designed separately to meet the flip-chip requirements of the first light-emitting chip 21, while also meeting its height requirements. Optionally, the light-emitting unit 2 is mounted on the substrate 1 through a solder layer. For details, please refer to... Figure 5The light-emitting unit 2 is fixed to the first die-bonding region and the second die-bonding region respectively by solder layer 7. When fixing the first light-emitting chip 21, solder layer 7 is a conductive adhesive layer; when fixing the second light-emitting chip, solder layer 7 is an insulating adhesive layer. The conductive adhesive material in the conductive adhesive layer has multiple options, including but not limited to solder paste and conductive silver paste, preferably solder paste, which has better resistance to moisture and chip push force than silver paste, resulting in better reliability. The insulating adhesive material in the insulating adhesive layer has multiple options, including but not limited to epoxy resin. The thickness of solder layer 7 can be flexibly adjusted according to the structure of the light-emitting chip and the required height; no specific limitation is made in this application. In some embodiments, pads can be provided on the substrate 1, and then the first light-emitting chip 21 and the second light-emitting chip 22 are fixed to the pads by solder layer 7.
[0046] Furthermore, the bonding area 32 includes a cathode bonding area 321 and a common anode bonding area 322. The cathode bonding area 321 and the die bonding area 31 are correspondingly arranged, and the die bonding area 31 and the bonding area 32 are electrically connected by bonding wires 35. Moreover, the front circuit board 3 also includes a through hole 33 penetrating the substrate 1 for realizing the electrical connection between the front circuit board 3 and the back circuit board 4.
[0047] Accordingly, please refer to Figure 4 The back circuit board 4 includes a pin area 41, which is correspondingly disposed with the bonding wire area 32, and the pin area 41 and the bonding wire area 32 are electrically connected through the through-hole 33. Specifically, the pin area 41 includes a cathode pin area 411 and an anode pin area 412, and the number of cathode pin areas 411 depends on the number of light-emitting chips. Specifically, the cathode end of each light-emitting chip is electrically connected to a corresponding different cathode bonding wire area 321 through a bonding wire 35, and then connected to a corresponding different cathode pin area 411 through the through-hole 33. The anode end of each light-emitting chip is electrically connected to a common anode bonding wire area 322 through a bonding wire 35, and then connected to the same anode pin area 412 through the through-hole 33.
[0048] Furthermore, the through-holes 33 are disposed at the corners of the substrate 1. The number of through-holes 33 can be determined according to the number of light-emitting chips. Generally, the cathode of each light-emitting chip corresponds to a different through-hole 33, while the anode corresponds to the same through-hole 33. The front circuit board 3 is covered with ink 37, that is, the through-holes 33 and the bonding wire area 32 connected to the through-holes 33 are covered with ink 37 to prevent moisture from entering the interior of the light-emitting unit 2 through the through-holes 33. When the ink 37 covers the location of the through-hole 33, the cavity of the through-hole 33 needs to be filled to support the ink 37. Of course, the through-hole 33 can also be a solid conductive post. This application does not specifically limit the through-hole 33.
[0049] Optionally, the front circuit board 3 further includes an insulating region 34, which separates the die-bonding regions 31 to prevent mutual conductivity, and also separates the wire bonding regions 32 to prevent mutual conductivity.
[0050] Existing Mini-LED chips are prone to polarity identification errors during customer placement, leading to malfunctions and extended placement time. Optionally, the top and / or bottom of the substrate 1 are provided with marking structures 5 for positioning and identifying the polarity of the LED chips. For example, please refer to... Figure 4 To facilitate polarity identification during client mounting, the marking structure 5 can be irregular in shape. This application does not specifically limit the shape and specific position of the marking structure 5, as long as it meets the requirements for polarity identification.
[0051] Optionally, please refer to Figure 5 The substrate 1 is coated with encapsulating adhesive 6 to seal and protect the light-emitting unit 2. This protects the light-emitting unit 2 from moisture, dust, chemicals, and other external environmental factors. It also seals and covers the electrodes and bonding wires 35 within the light-emitting unit 2, ensuring reliable electrical connections and extending the lifespan of the Mini-LED chips. The encapsulating adhesive 6 can be made from multiple materials, including but not limited to epoxy resin, silicone resin, and silicone gel. Furthermore, diffusing powders or phosphors composed of silica or silica can be added to the encapsulating adhesive 6. The phosphors can be composed of nitrides, silicates, chromium potassium chloride, chromium lutetite, etc.
[0052] Accordingly, this utility model also provides an LED display screen, which includes display Mini-LED lamp beads as described above.
[0053] The above-disclosed embodiment is merely a preferred embodiment of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.
Claims
1. A display Mini-LED lamp bead, characterized in that, include: The support includes a horizontally arranged base plate; A light-emitting unit mounted on the bracket includes a first light-emitting chip for emitting red light and a second light-emitting chip for emitting colors other than red light. The first light-emitting chip is inverted on the bracket, and the second light-emitting chip is upright on the bracket. The front circuit board disposed on the top of the substrate; And a back circuit board disposed at the bottom of the substrate.
2. The Mini-LED LED bead as described in claim 1, characterized in that, The height of the first light-emitting chip is the same as the height of the second light-emitting chip.
3. The Mini-LED lamp bead for display as described in claim 1 or 2, characterized in that, In the light-emitting unit, the first light-emitting chip and the second light-emitting chip are arranged sequentially on the central axis of the substrate and are symmetrical about the center point, and the first light-emitting chip and the second light-emitting chip are arranged at equal intervals.
4. The Mini-LED LED bead as described in claim 1, characterized in that, The first light-emitting chip and / or the second light-emitting chip in the light-emitting unit are isolated from each other.
5. The Mini-LED lamp bead as described in claim 1, characterized in that, The front circuit board includes a die-bonding area and a wire bonding area, and the first light-emitting chip and the second light-emitting chip are respectively disposed in different die-bonding areas; The bonding area includes a cathode bonding area and a common anode bonding area. The cathode bonding area and the die bonding area are correspondingly arranged, and the die bonding area and the bonding area are electrically connected by bonding wires.
6. The Mini-LED lamp bead as described in claim 5, characterized in that, The front circuit board also includes through holes penetrating the substrate; The back circuit board includes a pin area, which is correspondingly arranged with the bonding wire area, and the pin area and the bonding wire area are electrically connected through the through-hole.
7. The Mini-LED LED bead as described in claim 6, characterized in that, The through-holes are located at the corners of the substrate, and the front circuit board is covered with ink.
8. The Mini-LED lamp bead as described in claim 5, characterized in that, The front circuit board also includes an insulating area, which separates the die-bonding areas to prevent mutual conductivity, and at the same time separates the bonding wire areas to prevent mutual conductivity. The light-emitting unit is fixed to the substrate by a solder layer. When fixing the first light-emitting chip, the solder layer is a conductive adhesive layer, and when fixing the second light-emitting chip, the solder layer is an insulating adhesive layer.
9. The Mini-LED lamp bead as described in claim 1, characterized in that, The top and / or bottom of the substrate are provided with marking structures for positioning and identifying the polarity of the LED beads; The substrate is covered with encapsulating adhesive for sealing and protecting the light-emitting unit.
10. An LED display screen, characterized in that, It includes display Mini-LED beads as described in any one of claims 1-9.