Light bar and backlight module

Abstract

The invention relates to the technical field of LEDs, and discloses a light bar which comprises a substrate, a plurality of bonding pads are arranged on the substrate, and each bonding pad is correspondingly provided with a light-emitting assembly. The light-emitting assembly comprises a flip LED chip, a retaining wall, fluorescent glue and a lens arranged on the substrate, the lens comprises a light receiving port and a reflecting surface opposite to the light receiving port, and the flip LED chip is connected with the bonding pad and arranged in the light receiving port; the retaining wall is arranged in the light receiving opening and surrounds the flip LED chip, and the height of the retaining wall is larger than or equal to that of the flip LED chip; and the fluorescent glue covers the flip LED chip and is arranged in an area enclosed by the retaining wall. By arranging the retaining wall, the proportion of side light can be reduced, the light intensity distribution can be adjusted, the distribution of the LEDs can reach a more uniform effect by matching with light receiving of the lens and light expanding of the reflecting surface, and therefore the light emitting effect is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and particularly to a flip-chip LED strip and a backlight module that cooperate with five-sided light emission. Background Art

[0002] The flip-chip LED with five-sided light emission is different from the conventional single-sided light-emitting LED. This flip-chip LED with five-sided light emission not only has a much smaller size than the conventional LED. For example, the size of a conventional 3030 lamp bead is 3.0 * 3.0 * 0.6 mm, and the size of a 3535 flip-chip LED is 0.89 * 0.89 * 0.2 mm. Moreover, the flip-chip LED with five-sided light emission has a light-emitting angle of 140 - 170 degrees, the light intensity distribution is quite flat and the proportion of side light emission is relatively large, while the conventional LED has a light-emitting angle of about 120 degrees, the light intensity distribution is steeper and the proportion of side light emission is relatively small. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a lamp strip that reduces the proportion of side light and adjusts the light intensity distribution to ensure the light-emitting effect.

[0004] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0005] A lamp strip, characterized in that: it includes a substrate, and a plurality of pads are provided on the substrate, and a light-emitting component is correspondingly provided on each pad;

[0006] The light-emitting component includes a flip-chip LED chip, a barrier wall, a fluorescent glue, and a lens provided on the substrate. The lens includes a light-gathering port and a reflection surface opposite to the light-gathering port. The flip-chip LED chip is connected to the pad and is disposed inside the light-gathering port; the barrier wall is disposed inside the light-gathering port to surround the flip-chip LED chip, and the height of the barrier wall is greater than or equal to the height of the flip-chip LED chip; the fluorescent glue covers the flip-chip LED chip and is disposed within the area surrounded by the barrier wall.

[0007] Preferably, the height of the flip-chip LED chip is h;

[0008] The barrier wall is in a geometrically closed shape, and along the longitudinal section of the barrier wall, the width w of the side forming the barrier wall is 1.5h - 6h, and the height of the barrier wall is h - 5h.

[0009] Preferably, the width range of the barrier wall is 0.3 - 1.2 mm, and the height range of the barrier wall is 0.2 - 1 mm.

[0010] Preferably, the cross-section of the barrier wall is circular, elliptical or polygonal, and the shortest distance between the inner wall of the barrier wall and the outer wall of the flip-chip LED chip is greater than or equal to half of the height of the flip-chip LED chip.

[0011] Preferably, the height of the flip-chip LED chip is h, and the diameter of the phosphor glue is d, where d = (5 - 15)h.

[0012] Preferably, the diameter of the phosphor glue ranges from 1 to 3 mm.

[0013] Preferably, the end face of the phosphor glue away from the substrate is the light-emitting surface, the light-emitting surface is in the shape of a convex lens, and the maximum height of the phosphor glue is greater than the height of the retaining wall;

[0014] or the light-emitting surface is in the shape of a concave lens, and the height of the phosphor glue is less than the height of the retaining wall;

[0015] or the light-emitting surface is horizontal, and the height of the phosphor glue is equal to the height of the retaining wall.

[0016] Preferably, when the light-emitting surface is in the shape of a convex lens, the height of the retaining wall is H, and the maximum height of the phosphor glue is b, where 0.05 ≤ b - H ≤ 0.15;

[0017] When the light-emitting surface is in the shape of a concave lens, the height of the retaining wall is H, and the minimum height of the phosphor glue is b, where 0.05 ≤ H - b ≤ 0.15.

[0018] Preferably, the height of the flip-chip LED chip is h, and the diameter of the light-receiving port is D, where D = (15 - 35)h.

[0019] Preferably, the refractive index of the lens is 1.45 - 1.5, the diameter of the light-receiving port of the lens is 9 - 11 times the diameter of the flip-chip LED chip, and the diameter of the light-receiving port ranges from 3 to 7 mm.

[0020] Preferably, the substrate is provided with a card slot, the retaining wall is provided with a clamping portion, and the clamping portion is clamped in the card slot.

[0021] Preferably, the light-emitting angle of the light-emitting component is 140 - 170 degrees.

[0022] A backlight module includes a backlight cavity, a reflective paper, and the above-mentioned light bar. The light bar is disposed at the bottom of the backlight cavity, the reflective paper is attached to the substrate, and a plurality of through holes are provided on the reflective paper corresponding to the reflective components one by one, and the reflective components pass through the through holes.

[0023] Preferably, the backlight module further includes a back plate. The backlight cavity is disposed on the back plate, and a diffusion plate, a quantum dot film, a prism sheet, a diffusion sheet, and a liquid crystal screen are sequentially stacked above the backlight cavity along the optical path direction of the light bar.

[0024] The reflective paper includes a bottom plate and a surrounding plate protruding from the edge of the bottom plate, and the bottom plate is attached to the substrate;

[0025] The surrounding plate includes two first surrounding plates arranged oppositely and a second surrounding plate connecting the two ends of the two first surrounding plates, and a weakening hole is provided on the second surrounding plate.

[0026] Compared with the prior art, a light bar and a backlight module according to an embodiment of the present invention have the beneficial effects that: by arranging a retaining wall to surround the flip-chip LED chip, and the height of the retaining wall is greater than or equal to the height of the flip-chip LED chip, the retaining wall can reduce the proportion of side light and adjust the light intensity distribution, and then cooperate with the light collection of the lens and the light expansion of the reflecting surface to make the distribution of the flip-chip LED more uniform, thereby ensuring the light-emitting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of the light bar of the present invention.

[0028] Figure 2 is a schematic structural diagram of the light-emitting component of the present invention with the lens removed.

[0029] Figure 3 is a light-emitting effect diagram of the light-emitting component without a retaining wall.

[0030] Figure 4 is a light-emitting effect diagram of the light-emitting component with a retaining wall in the present invention.

[0031] Figure 5 is a schematic structural diagram of the lens of the present invention.

[0032] Figure 6 is a schematic structural diagram of the backlight module of the present invention.

[0033] Figure 7 is a schematic structural diagram of the reflective paper of the present invention.

[0034] Wherein: 1 - substrate, 2 - flip-chip LED chip, 3 - retaining wall, 4 - fluorescent glue, 5 - lens, 6 - light collection port, 7 - reflecting surface, 8 - reflective paper, 9 - through hole, 10 - weakening hole, 11 - card slot, 12 - pad, 13 - card slot, 14 - back plate, 15 - diffusion plate, 16 - quantum dot film, 17 - prism sheet, 18 - diffusion sheet, 19 - liquid crystal screen. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following will further describe in detail the specific embodiments of the present invention with reference to the drawings and embodiments. The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0036] Such as Figure 1-2As shown in the figure, a light bar according to a preferred embodiment of the present invention includes a substrate 1, and a plurality of pads 12 are provided on the substrate 1. A light-emitting component is correspondingly provided on each pad 12 ( Figure 1 Taking one of the light-emitting components as an example for illustration), the light-emitting angle of the light-emitting component is 140 to 170 degrees.

[0037] The light-emitting component includes a flip-chip LED chip 2, a retaining wall 3, a fluorescent glue 4, and a lens 5 provided on the substrate 1. The lens 5 includes a light-gathering port 6 and a reflection surface 7 opposite to the light-gathering port 6. The flip-chip LED chip 2 is connected to the pad 12 and is disposed inside the light-gathering port 6; the retaining wall 3 is disposed inside the light-gathering port 6 to surround the flip-chip LED chip 2, and the height of the retaining wall 3 is greater than or equal to the height of the flip-chip LED chip 2; the fluorescent glue 4 covers the flip-chip LED chip 2 and is disposed within the area surrounded by the retaining wall 3.

[0038] The reason why a flip chip is called "flip" is relative to the traditional wire bonding connection method (Wire Bongding) and the process after balling. The electrical surface of a traditional chip connected to the substrate through wire bonding faces upward, while the electrical surface of a flip chip faces downward, which is equivalent to flipping the former, so it is called a "flip chip" flip-chip LED chip. The flip-chip LED chip enables the light emitted by the light-emitting layer to directly emit from the other side of the electrode, and the substrate is finally peeled off, and the chip material is transparent.

[0039] For the light bar based on the above technical features, by providing the retaining wall 3 to surround the flip-chip LED chip 2, and the height of the retaining wall 3 is greater than or equal to the height of the flip-chip LED chip 2, the retaining wall 3 can reduce the proportion of side light and adjust the light intensity distribution. Together with the light-gathering of the lens 5 and the light expansion of the reflection surface 7, the light-emitting distribution of the flip-chip LED chip 2 can reach a more uniform effect, thereby ensuring the light-emitting effect.

[0040] The following uses a comparative example and a specific example to illustrate the technical effects of the present invention:

[0041] Comparative example, such as Figure 3 , which is a 65-inch COB light bar, selects a 35*35mil blue light chip LED, does not use a retaining wall glue to surround the LED, and only covers the LED with a fluorescent glue (glue width 2.1 mm, height 0.65 mm). The effect of its matching with the lens is that the light-emitting effect is not ideal.

[0042] Such as Figure 4, which is a 65-inch COB light bar, selects 35*35mil flip-chip LEDs, uses a barrier glue (the width of the barrier glue is 1.1 mm, the height is 0.35 mm, and the minimum distance from the LED is 0.3 mm) to surround the LEDs and covers the LEDs with a fluorescent glue (the width of the glue surface is 2.1 mm and the height is 0.35 mm). With the effect of the lens, the light-emitting effect is better.

[0043] The barrier 3 of the present invention is mainly used in combination with a Mini LED lens. The flip-chip LEDs are surrounded by a white barrier glue, and the LED chips 2 are filled and covered with a fluorescent glue 4, so that the flip-chip LEDs emitting light from five sides tend to emit light from a single plane infinitely, and the blue light of the flip-chip LEDs is converted into light of the required color. Finally, a lens is used to process the light-emitting effect of this structure. The shape of the barrier 3 is not fixed and can be circular, oval or polygonal in cross-section. However, the shortest distance between the inner wall of the barrier 3 and the outer wall of the flip-chip LED chip 2 needs to be greater than or equal to half of the height of the flip-chip LED chip 2. For example, if the height of the flip-chip LED chip 2 is 0.2 mm, the shortest distance between the inner wall of the barrier 3 and the outer wall of the flip-chip LED chip 2 needs to be greater than or equal to 0.1 mm.

[0044] In this embodiment, the barrier 3 is in a geometrically closed shape, and along the longitudinal section of the barrier 3, the size of the barrier 3 can be selected according to the height of the flip-chip LED chip. Specifically, if the height of the flip-chip LED chip 2 is h, the width w of the side forming the barrier 3 is 1.5h to 6h, and the height of the barrier 3 is h to 5h. The above relational expressions can be referred to when selecting. However, generally, the width range of the barrier 3 is 0.3 to 1.2 mm, and the height range of the barrier 3 is 0.2 to 1 mm to ensure the shielding effect. The barrier 3 can block the light emitted from the side of the flip-chip LED chip 2 and reflect the light to the front, solving the problem of light leakage from the side of the flip-chip LED chip 2 and making the LED emitting light from five sides tend to emit light from a single side, and the light pattern is also close to the light pattern of a conventional light board, which is convenient for the optical effect processing of the lens 5.

[0045] In this embodiment, the main material of the barrier 3 is glue, preferably silicone (including glues such as epoxy glue and UV glue), titanium dioxide or other white powders are added (the proportion is 20%-50%, and the reflectivity of the sealing glue with a thickness of 0.3 mm is greater than 95%), and then nano-level anti-settling powder (the proportion is 1%-3%) or other substances are added to the glue to increase the thixotropy of the glue. The thixotropy of the glue is adjusted according to the width and height of the barrier 3. The larger the ratio of the height to the width, the higher the required thixotropy.

[0046] In this embodiment, the size of the fluorescent glue 4 can also be determined according to the flip-chip LED chip 2. Specifically, if the height of the flip-chip LED chip 2 is h and the diameter of the fluorescent glue 4 is d, then d = 5 - 15h. When setting, the above relationship can be referred to. Generally, however, the diameter of the fluorescent glue 4 ranges from 1 to 3 mm. Cooperating with the flip-chip LED chip can make the light pattern of the flip-chip LED chip close to that of a conventional LED.

[0047] In this embodiment, the glue of the fluorescent glue 4 is selected as a glue with a relatively low viscosity (≤7000 mPa·s). A certain proportion of the corresponding phosphor is added according to the color gamut requirements of the product and stirred. Then it is added to a dispenser and the fluorescent glue is dispensed directly above the LED to cover the LED chip 2. The diameter of the glue surface is 1 - 3 mm, and the glue surface tends to be flat (slightly convex, slightly concave or flat cup), so that the light pattern of the flip-chip LED chip 2 is close to that of a conventional LED.

[0048] Specifically, the end face of the fluorescent glue 4 far from the substrate 1 is the light-emitting surface, and the light-emitting surface has three structural forms:

[0049] First, the light-emitting surface is convex lens-shaped (convex cup), and the maximum height of the fluorescent glue 4 is greater than the height of the retaining wall 3. When specifically setting, if the height of the retaining wall 3 is H and the height of the fluorescent glue 4 is b, and the maximum height of the fluorescent glue is b, 0.05 ≤ b - H ≤ 0.15. For example, when the height of the retaining wall 3 is 0.3 mm and the height of the fluorescent glue 4 is 0.35 mm, the test results are better.

[0050] Second, the light-emitting surface is concave lens-shaped (concave cup), and the height of the fluorescent glue 4 is less than the height of the retaining wall 3; if the height of the retaining wall 3 is H and the minimum height of the fluorescent glue 4 is b, 0.05 ≤ H - b ≤ 0.15b = H. For example, when the height of the retaining wall 3 is 0.5 mm and the height of the fluorescent glue 4 is 0.35 mm, the test results are better.

[0051] Third, the light-emitting surface is horizontal (flat cup), and the height of the fluorescent glue 4 is equal to the height of the retaining wall 3.

[0052] Please refer to the appendix Figure 5 , in this embodiment, it includes a reflective paper 8. The reflective paper 8 includes a bottom plate and a surrounding plate protruding from the edge of the bottom plate. The bottom plate is attached to the substrate 1, and a number of through holes 9 are provided on the bottom plate corresponding to the light-reflecting components one by one. The lens 5, the LED chip 2 pass through the through holes 9. Weakening holes 10 are provided on the surrounding plate. The weakening holes 10 are arranged in the area with high brightness in the light pattern distribution after the LED chip 2 passes through the lens 5 to weaken the light here, so as to achieve better uniformity.

[0053] Please refer to the attached Figure 5 , according to the structure of the retaining wall 3 and the light pattern, compared with the conventional LED lens, the design of the light collecting port 6 has changed. Specifically, the diameter of the light collecting port of this lens is larger than that of the conventional LED lens. When setting specifically, it can be set with reference to the height of the flip-chip LED chip 2. If the height of the flip-chip LED chip 2 is h and the diameter of the light collecting port 6 is D, D = (15 - 35)h. However, when generally setting, it is only necessary to ensure that the diameter range of the light collecting port 6 is 3 - 6 mm. Since backlight products have a greater requirement for the light emitting angle range compared to lighting products, the lens 5 used needs to have a wider light expansion range. Usually, the backlight lens is required to have a light expansion angle of more than 155°. Therefore, the lens 5 used in the flip-chip LED retaining wall structure also needs to meet the light expansion requirement of more than 155°. So its light expansion structure also needs to be adjusted, and its light expansion hole (i.e., the hole surrounded by the reflection surface) becomes larger and the hole height is lower to meet the light expansion requirement.

[0054] The following is a specific description of the specific structure of the lens 5:

[0055] The lens 5 is of a rotational body structure. Its optical surface includes an inner incident surface 510, an outer exit surface 520, and a lens bottom surface 530. The bottom end of the incident surface 510 is connected to the bottom end of the exit surface 520 through the lens bottom surface 530, and the incident surface 510 constitutes the light collecting port 6.

[0056] Specifically, the incident surface 510 is composed of a side incident surface 511 and a top incident surface 512 connected. The generatrix shapes of the side incident surface 511 and the top incident surface 512 are both like a section of a spiral, and the side incident surface 511 and the top incident surface 512 together constitute the light collecting port 6.

[0057] The exit surface 520 is composed of a curved total reflection surface 7, a conical exit surface 521, and a curved exit surface 522 connected. The generatrix shape of the curved exit surface 143c is like a section of a parabola.

[0058] There is a reflection ring 531 on the lens bottom surface 530, which can reduce the influence of Fresnel reflection. The shape of the reflection ring 531 can also be other various similar shapes such as an arc shape or a conical shape. The number of reflection rings 531 is determined according to the characteristics of the flip-chip LED chip 2, and is generally 1 - 6.

[0059] In this embodiment, to increase the bonding force between the retaining wall 3 and the substrate and facilitate the dispensing of the retaining wall glue, a card slot 11 is provided on the substrate 1, and the retaining wall 3 is provided with a clamping portion that is clamped in the card slot 11. The dimensions of the groove are as follows: width 0.8 - 1.2 mm, depth: 0.04 mm - 0.1 mm, and the diameter of the card slot 11 varies with the design of the retaining wall glue.

[0060] The following specific embodiments are used to verify the effect of this solution.

[0061]

[0062]

[0063] It can be concluded from the above specific embodiments that for the product to achieve the expected light-emitting effect, it is necessary to coordinate several factors such as the height of the retaining wall 3, the height of the fluorescent glue 4, and the cup shape of the fluorescent glue surface. The design of the synchronous lens 5 adjusts the light-receiving and light-diffusing structures of the retaining wall 3 based on these factors, so that the combination of the retaining wall 3 and the lens achieves the expected light-emitting effect.

[0064] Please refer to the appendix Figure 6 To solve the above technical problems, the present invention also provides a backlight module, which includes a backlight cavity, a reflective paper 8, and the above-mentioned light bar. The light bar is arranged at the bottom of the backlight cavity. Specifically, there are multiple light bars, and the multiple light bars are arranged in parallel. The reflective paper 8 is attached to the substrate 1, and a plurality of through holes 9 are provided on the reflective paper 8 corresponding to the reflective components one by one, and the reflective components pass through the through holes 9. The backlight module further includes a back plate 14, the backlight cavity is arranged on the back plate 14, and a diffusion plate 15, a quantum dot film 16, a prism sheet 17, a diffusion sheet 18, and a liquid crystal screen 19 are stacked in sequence along the optical path direction of the light bar above the backlight cavity.

[0065] Please refer to the appendix Figure 7 The reflective paper 8 includes a bottom plate and a surrounding plate protruding from the edge of the bottom plate. The bottom plate is attached to the substrate 1;

[0066] The surrounding plate includes two first surrounding plates arranged opposite to each other and a second surrounding plate connecting the two ends of the two first surrounding plates. A weakening hole 10 is provided on the second surrounding plate. The weakening hole 10 is used to weaken the light in the high-brightness area, so as to achieve better uniformity. The weakening hole 10 is set in the area with high brightness in the light pattern distribution after the flip-chip LED chip 2 passes through the lens 5.

[0067] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A light bar, characterized in that: It includes a substrate, on which a number of pads are provided, and a light-emitting component is correspondingly provided on each pad; The light-emitting component includes a flip-chip LED chip, a barrier wall, a fluorescent glue, and a lens provided on the substrate. The lens includes a light-receiving port and a reflecting surface opposite to the light-receiving port. The flip-chip LED chip is connected to the pad and is arranged inside the light-receiving port; the barrier wall is arranged inside the light-receiving port to surround the flip-chip LED chip, and the height of the barrier wall is greater than or equal to the height of the flip-chip LED chip; the fluorescent glue covers the flip-chip LED chip and is arranged in the area surrounded by the barrier wall.

2. The light bar according to claim 1, characterized in that: The height of the flip-chip LED chip is h; The barrier wall is geometrically closed, and along the longitudinal section of the barrier wall, the width w of the side forming the barrier wall is 1.5h - 6h, and the height of the barrier wall is h - 5h.

3. The light bar according to claim 1, characterized in that: The width range of the barrier wall is 0.3 - 1.2 mm, and the height range of the barrier wall is 0.2 - 1 mm.

4. The light bar according to claim 1, characterized in that: The cross-section of the barrier wall is circular, elliptical or polygonal, and the shortest distance between the inner wall of the barrier wall and the outer wall of the flip-chip LED chip is greater than or equal to half of the height of the flip-chip LED chip.

5. The light bar according to claim 1, characterized in that: The height of the flip-chip LED chip is h, and the diameter of the fluorescent glue is d, d = (5 - 15)h.

6. The light bar according to claim 1, characterized in that: The diameter range of the fluorescent glue is 1 - 3 mm.

7. The light bar according to claim 1, characterized in that: The end face of the fluorescent glue away from the substrate is the light-emitting surface. The light-emitting surface is convex lens-shaped, and the maximum height of the fluorescent glue is greater than the height of the barrier wall; or the light-emitting surface is concave lens-shaped, and the height of the fluorescent glue is less than the height of the barrier wall; or the light-emitting surface is horizontal, and the height of the fluorescent glue is equal to the height of the barrier wall.

8. The light bar according to claim 7, characterized in that: When the light-emitting surface is convex lens-shaped, the height of the barrier wall is H, and the maximum height of the fluorescent glue is b, 0.05 ≤ b - H ≤ 0.15; When the light-emitting surface is concave lens-shaped, the height of the barrier wall is H, and the minimum height of the fluorescent glue is b, 0.05 ≤ H - b ≤ 0.

15.

9. The light bar according to claim 1, characterized in that: The height of the flip-chip LED chip is h, and the diameter of the light-receiving port is D, D = (15 - 35)h.

10. The light bar according to claim 1, characterized in that: The refractive index of the lens is 1.45 - 1.

5. The diameter of the light-receiving port of the lens is 9 - 11 times the diameter of the flip-chip LED chip, and the diameter range of the light-receiving port is 3 - 7 mm.

11. The light bar according to claim 1, characterized in that: The substrate is provided with a card slot, and the barrier wall is provided with a clamping portion, and the clamping portion is clamped in the card slot.

12. The light bar according to claim 1, characterized in that: The light-emitting angle of the light-emitting component is 140 - 170 degrees.

13. A backlight module, characterized in that: It includes a backlight cavity, a reflective paper, and a light bar as described in any one of claims 1 - 12. The light bar is arranged at the bottom of the backlight cavity. The reflective paper is attached to the substrate, and a number of through holes are correspondingly provided on the reflective paper for the reflective components to pass through.

14. The backlight module according to claim 13, characterized in that: The backlight module further includes a back plate. The backlight cavity is arranged on the back plate. Above the backlight cavity, a diffusion plate, a quantum dot film, a prism sheet, a diffusion sheet, and a liquid crystal screen are sequentially stacked along the optical path direction of the light bar.

15. The backlight module according to claim 13 or 14, characterized in that: The reflective paper includes a bottom plate and a surrounding plate protruding from the edge of the bottom plate, and the bottom plate is attached to the substrate; The surrounding plate includes two first surrounding plates arranged oppositely and a second surrounding plate connecting both ends of the two first surrounding plates, and a weakening hole is provided on the second surrounding plate.

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