Laterally bent COB (Chip On Board) lamp strip

Abstract

The utility model provides a laterally-bent COB lamp strip which comprises a substrate, two rows of solid crystal positions are arranged on the upper surface of the substrate, a double-faced adhesive tape is attached to the lower surface of the substrate, and the position, located between the two rows of solid crystal positions, of the substrate is intermittently cut off or punched so that the strength of the position can be low; the crystal is arranged at the crystal fixing position; and the two rows of fluorescent glue are used for covering the crystals on the two rows of crystal fixing positions, and the two rows of fluorescent glue are overlapped. The two rows of solid crystal positions are respectively parallel to the symmetry axis of the substrate and are distributed on two sides of the symmetry axis of the substrate; the intermittent cutting or punching position is located on the symmetry axis of the base plate. Compared with the prior art, the COB lamp strip has the advantages that the plane structure of the COB is changed into the space structure through folding, positive bending and lateral bending can be achieved, positive bending and lateral bending can be achieved, the technology is simple, the light emitting effect is ideal, and the application scene of the lamp strip is greatly expanded.

Description

Technical Field

[0001] This application relates to the field of decorative lighting technology, and in particular to a side-bending COB light strip. Background Technology

[0002] Applying COB (Chip On Board Light) technology, which integrates multiple LED chips onto the same substrate, to create lighting devices suitable for commercial lighting and aesthetically pleasing lighting effects is a current trend.

[0003] For COB LED strips, bending vertically with the emitting surface as the reference is called a forward bend, while bending horizontally with the side of the emitting surface as the reference is called a side bend. Conventional COB LED strips do not have a side bend function and can only bend vertically. If a side bend is forced, the FPC (Flexible Printed Circuit) substrate will be torn. Existing products with side bend functions are expensive, have complex processes, and their product shape and light output effect are not ideal, resulting in asymmetrical light output. Summary of the Invention

[0004] The purpose of this application is to provide a side-bending COB light strip to solve the problems of existing COB light strips that do not have side-bending function or have high side-bending cost, complex process, and asymmetrical light emission.

[0005] A side-bending COB light strip, the side-bending COB light strip comprising:

[0006] The substrate has two rows of die-bonding sites on its upper surface and double-sided adhesive on its lower surface. The substrate is intermittently cut or punched at the midpoint between the two rows of die-bonding sites to reduce the strength at that point.

[0007] Crystal, located at the solid site;

[0008] Two rows of fluorescent adhesive are used to cover the crystals on the two solid sites, and the two rows of fluorescent adhesive overlap.

[0009] The two rows of die-bonding sites are parallel to the symmetry axis of the substrate and are distributed on both sides of the symmetry axis of the substrate; the intermittent cutting or drilling positions are located on the symmetry axis of the substrate.

[0010] The crystal includes conductive adhesive and a flip chip, with the flip chip electrically connected to the conductive adhesive.

[0011] The thickness of the overlapping area of ​​the two rows of fluorescent adhesive ranges from 0.8 to 1.2 mm.

[0012] The two rows of die-bonding positions are symmetrically arranged around the axis of symmetry of the substrate, and the lower surface of the substrate is folded along the axis of symmetry to allow the double-sided adhesive to adhere completely.

[0013] As described above, the side-bending COB light strip and its manufacturing method of this application have the following beneficial effects:

[0014] By folding the COB (Chip-on-Board) strip in half to transform its planar structure into a spatial structure, both straight and side bends can be achieved. This simple process produces ideal light output and greatly expands the application scenarios of LED strips. Attached Figure Description

[0015] Figure 1 This application provides a schematic diagram of the structure of a side-bending COB light strip before it is folded in half, according to one embodiment of the present application.

[0016] Figure 2 This is a schematic diagram of the structure of a substrate provided in an embodiment of this application;

[0017] Figure 3 This is a schematic diagram of the structure of a side-bending COB light strip after it has been folded in half, according to an embodiment of this application. Detailed Implementation

[0018] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0020] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of this application, should still fall within the scope of the technical content disclosed in this application. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of this application. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this application.

[0021] like Figures 1-3 As shown, Figure 1 This is a schematic diagram of the structure of a side-bending COB light strip before it is folded in half, according to an embodiment of this application. Figure 2 This is a schematic diagram of the structure of substrate 1 provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of a side-bent COB light strip after folding, provided in one embodiment of this application. The method for preparing the side-bent COB light strip includes steps S1-S4:

[0022] S1. Two rows of die-bonding sites are provided on the upper surface of substrate 1, and the substrate 1 is intermittently cut or perforated at the midpoint between the two rows of die-bonding sites to reduce the strength at that point; Step S1 includes steps S11-S12:

[0023] S11. Set the two rows of die-bonding sites to be parallel to the axis of symmetry 10 of the substrate 1 and distributed on both sides of the axis of symmetry 10 of the substrate 1.

[0024] In this embodiment, see Figure 2 The symmetry axis 10 of the substrate 1 is located in the middle of the two rows of die-bonding sites, and the substrate 1 is preferably made of FPC material.

[0025] S12. Intermittently cut or punch holes along the axis of symmetry 10 of substrate 1.

[0026] In this embodiment, by intermittently cutting or punching holes at the axis of symmetry 10, that is, drawing dashed lines or dots along the axis of symmetry 10 and opening at the dashed lines or dots, the strength at the axis of symmetry 10 of the substrate 1 can be reduced, so that when folded, it can be folded along the axis of symmetry 10.

[0027] S2, Solidify the crystal at the solidification site; Step S2 includes steps S21-S23:

[0028] S21. Apply conductive adhesive to the die-bonding site using screen printing.

[0029] In this embodiment, coating conductive adhesive by screen printing is a method of uniformly coating conductive adhesive onto a substrate using screen printing technology. Specific steps include S211-S215:

[0030] S211. First, select a suitable conductive adhesive paste to ensure it has good conductivity and adhesion. Conductive adhesives are typically composed of conductive particles (such as silver powder) and binders.

[0031] S212. Create a screen printing plate with the desired pattern. Screen printing plates are usually made of stainless steel or nylon, coated with photosensitive emulsion, and the desired pattern is formed through exposure and development.

[0032] S213. Place the conductive adhesive under the screen printing plate and use a squeegee or similar tool to evenly spread the adhesive across the screen, transferring it onto the substrate through the openings in the screen. This process requires controlling the squeegee pressure and printing speed to ensure the uniformity and consistency of the coating.

[0033] S214. After coating, the conductive adhesive needs to be dried and cured. This typically involves low-temperature drying to remove solvents, followed by heat treatment to complete curing.

[0034] S215. Finally, conduct a quality inspection of the applied conductive adhesive to ensure that its conductivity and adhesion meet the requirements. Repair or recoat if necessary.

[0035] S22. Use a die bonder to pick up and place flip-chips at the die bonder position.

[0036] In this embodiment, the chip placement and pick-up step of the die bonder is a core step in the COB die bond process, directly affecting chip positioning accuracy and yield. The steps of placing and picking up the chip at the die bond position using the die bonder include S221-S225:

[0037] S221. The pre-treated substrate 1 (PCB or ceramic substrate 1) is fixed on the die bonder table by vacuum adsorption or clamping to ensure flatness and no warping; the cut wafer (chip array) is pasted on the UV film, and the expansion film is irradiated by UV light to increase the chip spacing, making it easier for the robotic arm to pick up.

[0038] S222. Nozzle material selection: ceramic or carbon fiber (anti-static, wear-resistant). Diameter must match chip size (e.g., <100μm nozzle for MiniLED chips). Vacuum adsorption is used, with vacuum pressure adjusted (typically 50-150kPa) to avoid excessive suction causing chip cracking. A high-resolution camera (5μm accuracy) identifies chip positions on the wafer, automatically avoiding dicing lines or defective chips. Nozzle height is adjusted according to chip thickness (e.g., 150μm for LED chips) to prevent collisions with the wafer. Nozzle vacuum pressure range is 50-150kPa; the adjustment principle is that smaller chip sizes require lower pressure.

[0039] S223. The robotic arm moves at high speed (1-3m / s), with X / Y axis accuracy of ±3μm and Z axis fine adjustment to avoid impact; the rotation axis (θ axis) corrects chip angle offset (e.g., within ±1°); the dual-camera system simultaneously identifies the alignment mark (Fiducial Mark) on substrate 1 and the position of chip electrodes; the coordinates are adjusted in real time according to the thermal expansion or deformation of substrate 1 to ensure alignment accuracy (within ±5μm).

[0040] S224. Place the chip via contact control; decelerate before the nozzle contacts substrate 1, and apply light pressure (0.1-0.5N) after contact to prevent chip breakage; place the chip within 5 seconds after dispensing to ensure uniform diffusion of the adhesive (adhesive layer thickness 5-15μm); after the vacuum is turned off, detect the nozzle rebound height using a force sensor to confirm that the chip has completely detached from the nozzle; a high-sensitivity sensor monitors the placement process, and if abnormal resistance (such as adhesive adhesion) is detected, an alarm is triggered and the position is recorded.

[0041] S225. Immediately after placement, photograph the chip position to detect offset, tilt, or glue overflow (if the electrode coverage is >10%, it is judged as NG); classify the defect type (such as offset, missing glue, flip) through machine learning algorithm and feed it back to the die bonder to adjust the parameters; record the pressure curve of each placement, and if abnormal fluctuations occur (such as chip breakage signal), automatically stop the machine for troubleshooting.

[0042] S23. Bake at 170-180℃ for 1-1.5 hours.

[0043] In this embodiment, a packaging substrate 1 is taken, and die bonding adhesive is applied to the die bonding tank of the packaging substrate 1. COB chips are bonded to the die bonding tank, ultrasonically treated for 3 minutes, left to stand for 5 minutes, and then transferred to an oven for baking for 1.5 hours. The baking temperature is preferably 170°C. During baking, ultrasonic conditions are used, with an ultrasonic power of 60W and an ultrasonic frequency of 20kHz.

[0044] S3. Two rows of fluorescent adhesive 3 are poured into the die-bonding area to cover the crystals 2 on the two rows of die-bonding sites, and the two rows of fluorescent adhesive 3 overlap; Step S3 includes steps S31-S33:

[0045] S31. Two rows of fluorescent adhesive 3 are poured into the die bonding area to excite white light through the fluorescent adhesive 3, so that the thickness of the overlapping part of the two rows of fluorescent adhesive 3 is 0.8-1.2mm.

[0046] In this embodiment, the overlapping area of ​​the two rows of fluorescent adhesive 3 is located around the symmetry axis 10 of the substrate 1. See [link / reference needed]. Figures 1-3 The overlapping area of ​​the two rows of fluorescent adhesive 3 wraps around the upper surface of the symmetry axis 10 of the substrate 1. When folded downwards, the overlapping area becomes the side of the light strip. Therefore, one side of the side-bent COB light strip in this case can also emit light.

[0047] S32, bake for 0.5-1 hour.

[0048] In this embodiment, baking is performed under ultrasonic conditions with an ultrasonic power of 60W and an ultrasonic frequency of 20kHz. Baking is preferably carried out for 50 minutes at 150°C.

[0049] S33, cool for 1-1.2 hours to allow the glue to dry.

[0050] In this embodiment, the temperature is reduced at a rate of 2°C / min.

[0051] S4. Apply double-sided adhesive to the lower surface of substrate 1, and fold substrate 1 downwards along the middle of the two rows of die-bonding positions to adhere the lower surface of substrate 1. Step S4 includes steps S41-S42:

[0052] S41. The two rows of die-bonding positions are symmetrically arranged with respect to the axis of symmetry 10 of the substrate 1.

[0053] In this embodiment, the two rows of die-bonding positions are symmetrically arranged with respect to the axis of symmetry 10 of the substrate 1, which can make the upper and lower surfaces emit light uniformly after folding.

[0054] S42. Fold the lower surface of substrate 1 along the axis of symmetry 10 to ensure that the double-sided adhesive is completely adhered.

[0055] In this embodiment, the axis of symmetry 10 divides the lower surface of the substrate 1 into two equal halves. Folding the lower surface of the substrate 1 along the axis of symmetry 10 allows the double-sided adhesive to adhere completely, with the lower surface fully in an adhesive state. Thus, this invention utilizes the folding technique to transform the planar structure of the COB into a spatial structure. Without folding, it is a normal COB light strip with a large luminous surface. Folding it creates a side-bent COB light strip, allowing for partial forward bending and partial side bending, forming a 3DCOB light strip, greatly expanding the application scenarios of the light strip.

[0056] See Figures 1-3 The side-bending COB light strip provided in this case is prepared by the preparation method of the side-bending COB light strip in this case. The side-bending COB light strip includes a substrate 1, a crystal 2 and two rows of fluorescent adhesive 3.

[0057] The upper surface of substrate 1 has two rows of die-bonding positions, and the lower surface is covered with double-sided adhesive. Intermittent cutting or drilling is performed on substrate 1 at the midpoint between the two rows of die-bonding positions to reduce strength at that location. Crystal 2 is disposed at the die-bonding positions. The two rows of die-bonding positions are parallel to the axis of symmetry 10 of substrate 1 and are distributed on both sides of the axis of symmetry 10; the intermittent cutting or drilling is performed on the axis of symmetry 10 of substrate 1.

[0058] In this embodiment, the symmetry axis 10 of the substrate 1 is located in the middle of the two rows of die-bonding sites, and the substrate 1 is preferably made of FPC material. By intermittently cutting or punching holes at the symmetry axis 10, that is, drawing dashed lines or dots along the symmetry axis 10 and opening at the dashed lines or dots, the strength at the symmetry axis 10 of the substrate 1 can be reduced, so when folded, it can be folded along the symmetry axis 10.

[0059] Two rows of fluorescent adhesive 3 are used to cover the crystals 2 on the two rows of solid sites, and the two rows of fluorescent adhesive 3 overlap. The thickness of the overlapping part of the two rows of fluorescent adhesive 3 ranges from 0.8 to 1.2 mm.

[0060] In this embodiment, the overlapping area of ​​the two rows of fluorescent adhesive 3 is located around the symmetry axis 10 of the substrate 1. See [link / reference needed]. Figures 1-3 The overlapping area of ​​the two rows of fluorescent adhesive 3 wraps around the upper surface of the symmetry axis 10 of the substrate 1. When folded downwards, the overlapping area becomes the side of the light strip. Therefore, one side of the side-bent COB light strip in this case can also emit light.

[0061] The crystal 2 includes conductive adhesive and a flip chip, with the flip chip electrically connected to the conductive adhesive.

[0062] In this embodiment, solder resist is fabricated on the upper surface of substrate 1, and holes are drilled to form packaging substrate 1. Packaging substrate 1 is taken, and die bond adhesive is applied to the die bond groove of packaging substrate 1. COB chips are then bonded to the die bond groove. A hot-press ultrasonic bonding process is used to bond the COB chips to the circuitry on the surface of packaging substrate 1 using gold wires.

[0063] The two rows of die-bonding positions are symmetrically arranged with respect to the axis of symmetry 10 of the substrate 1. The lower surface of the substrate 1 is configured to be folded along the axis of symmetry 10 so that the double-sided adhesive can be completely adhered.

[0064] In this embodiment, the two rows of die-bonding positions are symmetrically arranged around the axis of symmetry 10 of the substrate 1, which allows for uniform light emission on both the upper and lower surfaces after folding. The axis of symmetry 10 divides the lower surface of the substrate 1 into two equal halves. Folding the lower surface of the substrate 1 along the axis of symmetry 10 allows for complete adhesion of the double-sided adhesive, with the lower surface fully adhered. Thus, this invention utilizes the folding technique to transform the planar structure of the COB into a spatial structure. Without folding, it is a normal COB light strip with a large light-emitting surface. Folding it creates a side-bent COB light strip, which can also achieve partial forward bending and partial side bending, forming a 3DCOB light strip, greatly expanding the application scenarios of the light strip.

[0065] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A side-bending COB light strip, characterized in that, The side-bending COB light strip includes: The substrate has two rows of die-bonding sites on its upper surface and double-sided adhesive on its lower surface. The substrate is intermittently cut or punched at the midpoint between the two rows of die-bonding sites to reduce the strength at that point. Crystal, located at the solid site; Two rows of fluorescent adhesive are used to cover the crystals on the two rows of solid crystal sites, and the two rows of fluorescent adhesive overlap. The two rows of die-bonding sites are parallel to the symmetry axis of the substrate and are distributed on both sides of the symmetry axis of the substrate; the intermittent cutting or drilling positions are located on the symmetry axis of the substrate.

2. The side-bend COB lamp strip according to claim 1, characterized in that, The crystal includes conductive adhesive and a flip chip, with the flip chip electrically connected to the conductive adhesive.

3. The side-bending COB light strip according to claim 1, characterized in that, The thickness of the overlapping area of ​​the two rows of fluorescent adhesive ranges from 0.8 to 1.2 mm.

4. The side-bend COB lamp strip according to claim 1, characterized in that, The two rows of die-bonding positions are symmetrically arranged around the axis of symmetry of the substrate, and the lower surface of the substrate is folded along the axis of symmetry to allow the double-sided adhesive to adhere completely.

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