An LED backlight and its manufacturing method

Abstract

This invention discloses an LED backlight and its manufacturing method. The LED backlight includes a substrate, LED chips, and a driver IC. The substrate has a first side surface, and the LED chips and driver IC are spaced apart on the first side surface. The first side surface has M partitions, each partition containing a driver IC and N channels. The driver IC controls X LED chips through one channel, where M, N, and X are all integers greater than or equal to 1, and N is less than or equal to 6. The driver IC is white. This invention's LED backlight uses a white-looking driver IC with fewer channels, which not only simplifies the circuit design of the LED backlight but also significantly reduces the absorption of light emitted by the LED chips, thereby avoiding shadows on the displayed screen.

Description

Technical Field

[0001] This invention relates to the field of LED technology, and in particular to an LED backlight and its manufacturing method. Background Technology

[0002] Currently, LED backlights typically employ a combined lamp and driver structure, meaning both the driver unit and the light-emitting unit are mounted on the same substrate. When the driver unit and the light-emitting unit are mounted on the same side of the substrate, the driver IC, which uses a black substrate, will absorb or block light, affecting the optical performance of the backlight. The driver IC used in the driver unit generally drives 32 or more channels, and each channel contains a relatively large number of chips. When the number of chips in the backlight is large, the circuit layout becomes extremely complex, and the IC becomes quite large due to the large number of driving channels. Placing it on the same side as the light-emitting unit will obstruct the light emission of the chips, and the maintenance cost is also high. Summary of the Invention

[0003] One objective of this invention is to provide an LED backlight that has a simple structure, a small driver IC size, a low number of channels, a simple circuit layout, and good display effect.

[0004] Another objective of this invention is to provide a method for manufacturing an LED backlight that is simple to operate and can use a single solder paste printing process to meet the requirements of different amounts of solder paste on the substrate.

[0005] To achieve this objective, the embodiments of the present invention adopt the following technical solutions:

[0006] In a first aspect, an LED backlight is provided, comprising a substrate, LED chips, and a driver IC. The substrate has a first side surface, and the LED chips and the driver IC are spaced apart on the first side surface. The first side surface has M partitions, and each partition contains a driver IC and N channels. The driver IC controls X LED chips through one of the channels, wherein M, N, and X are all integers greater than or equal to 1, and N is less than or equal to 6. The driver IC is white in appearance.

[0007] As a preferred embodiment of the LED backlight, the driver IC is encapsulated in a plastic molding compound, which is white plastic.

[0008] Alternatively, the outer surface of the driver IC may be coated with white glue.

[0009] As a preferred embodiment of the LED backlight, the molding compound contains a whitening agent, and the molding compound is one of epoxy resin, epoxy resin mixture, silicone resin or polyimide.

[0010] As a preferred embodiment of the LED backlight, the white adhesive is either an epoxy resin or a silicone resin containing a whitening agent.

[0011] As a preferred embodiment of the LED backlight, the center-to-center spacing between adjacent LED chips is 4mm to 30mm.

[0012] As a preferred embodiment of the LED backlight, the LED chip is a flip-chip LED.

[0013] Secondly, a method for manufacturing an LED backlight is provided, comprising the following steps:

[0014] S100. Provide a substrate and a stencil, align the stencil with the substrate, and then simultaneously apply solder paste through the stencil to the LED pads and IC pads of the substrate, wherein the amount of solder paste on the LED pads and the IC pads is different.

[0015] S200: Provides an LED chip and a white-looking driver IC. The LED chip and the driver IC are soldered onto the LED pads and the IC pads respectively using reflow soldering to form the LED backlight.

[0016] In a preferred embodiment of the LED backlight manufacturing method, a plurality of first through holes and second through holes are spaced apart on the steel mesh. The first through holes correspond to the positions of the LED pads, and the second through holes correspond to the positions of the IC pads. The depth of the first through holes is less than the depth of the second through holes.

[0017] As a preferred embodiment of the manufacturing method of the LED backlight, the steel mesh includes a mesh plate, and a boss is provided on the side of the mesh plate opposite to the substrate. One boss is provided for each second through hole, and the second through hole passes through the boss.

[0018] As a preferred embodiment of the manufacturing method of the LED backlight, the depth of the first through hole is 0.01mm to 0.03mm, and the depth of the second through hole is 0.05mm to 0.1mm.

[0019] As a preferred embodiment of the manufacturing method of the LED backlight, before step S200, the driver IC is encapsulated in the white plastic.

[0020] Thirdly, a method for manufacturing an LED backlight is provided, comprising the following steps:

[0021] S100. Provide a substrate and a stencil, align the stencil with the substrate, and then simultaneously apply solder paste through the stencil to the LED pads and IC pads of the substrate, wherein the amount of solder paste on the LED pads and the IC pads is different.

[0022] S200: Provide an LED chip and a driver IC, and use reflow soldering to solder the LED chip and the driver IC onto the LED pads and the IC pads respectively to form the LED backlight;

[0023] S300. Apply white glue to the driver IC and dry the LED backlight with the driver IC in an oven to give the driver IC a white appearance.

[0024] The beneficial effects of this invention are as follows: By setting the number of channels N of the driver IC to 1 to 6, the number of LED chips controlled by each driver IC is small, which simplifies the circuit between the driver IC and the LED chips in each partition. When the driver IC needs to be repaired, only the damaged driver IC needs to be replaced, resulting in low repair costs. Both the LED chips and the driver IC are located on the first side of the substrate, and the driver IC has a white appearance. The driver IC can significantly reduce the absorption and emission of light by the LED chips, avoiding the problem of shadows on the display screen. At the same time, in the entire backlight module, the driver IC can support other optical components in the backlight module, such as the diffuser plate, without the need to add other support components on the substrate, thereby reducing the manufacturing difficulty and cost of the backlight module. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This is a front view of an LED backlight according to an embodiment of the present invention.

[0027] Figure 2 This is a side view of an LED backlight according to an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram showing the installation positions of the LED backlight and optical components according to an embodiment of the present invention.

[0029] Figure 4 This is a front view of an LED backlight with a driver IC coated with white glue, according to an embodiment of the present invention.

[0030] Figure 5 This is a front view of an LED backlight having a driver IC encapsulated in plastic, according to an embodiment of the present invention.

[0031] Figure 6This is a front view of a partition on a substrate of an LED backlight according to an embodiment of the present invention.

[0032] Figure 7 This is a front view of a partition on a substrate of another LED backlight according to an embodiment of the present invention.

[0033] Figure 8 This is a cross-sectional view showing the fit between the substrate and the stencil during the manufacturing of the LED backlight according to the present invention.

[0034] In the picture:

[0035] 1. Substrate; 11. First side; 111. Partition; 2. LED chip; 3. Driver IC; 4. White glue; 5. Stencil; 51. First through hole; 52. Second through hole; 53. Boss; 6. Optical component. Detailed Implementation

[0036] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] Reference Figures 1 to 3As shown, an embodiment of the present invention provides an LED backlight, including a substrate 1, LED chips 2, and a driver IC 3. The substrate 1 has a first side surface 11. The LED chips 2 and the driver IC 3 are spaced apart on the first side surface 11. The first side surface 11 has M partitions 111. Each partition 111 contains a driver IC 3 and N channels. The driver IC 3 controls X LED chips 2 through one channel, where M, N, and X are all integers greater than or equal to 1, and N is less than or equal to 6. The driver IC 3 is white. Specifically, the driver IC 3 is a discrete driver IC, and one driver IC 3 controls multiple LED chips 2 to emit light through one channel. By setting the number of channels N of the driver IC3 to 1 to 6, the number of LED chips 2 controlled by each driver IC3 is small, which simplifies the circuit between the driver IC3 and the LED chip 2 in each partition 111. When the driver IC3 needs to be repaired, only the damaged driver IC3 needs to be replaced, resulting in low repair costs. At the same time, the small number of channels of the driver IC3 can reduce the size of the driver IC3, so that both the driver IC3 and the LED chip 2 can be placed on the front side of the substrate 1, and the driver IC3 will not block the light emission of the LED chip 2. The LED chip 2 and the driver IC3 are both placed on the first side 11 of the substrate 1, and the driver IC3 has a white appearance. The driver IC3 can not only significantly reduce the absorption of the light emitted by the LED chip 2, avoiding the problem of shadows on the display screen, but also support other optical components 6 in the backlight module such as the diffuser plate. There is no need to add other support components on the substrate 1, thereby reducing the manufacturing difficulty of the backlight module, shortening the production cycle of the LED backlight, and reducing costs.

[0040] Reference Figure 4 As shown, in this embodiment, the outer surface of the driver IC3 is coated with white glue 4. After the LED chip 2 and the driver IC3 are soldered to the substrate 1, the driver IC3, which has a conventional black casing, is coated with white glue 4. After drying and hardening, the driver IC3 has a white appearance.

[0041] Specifically, white glue 4 is epoxy resin or silicone resin.

[0042] Reference Figure 5 As shown, in other embodiments, the driver IC3 is encapsulated with a white plastic molding compound. By using a white molding compound to encapsulate the driver IC3 during manufacturing, the driver IC3 achieves a white appearance.

[0043] Specifically, the molding compound contains a whitening agent. The molding compound is one of epoxy resin, epoxy resin mixture, silicone resin or polyimide, and the whitening agent is titanium dioxide, etc.

[0044] Specifically, the center-to-center spacing between adjacent LED chips 2 is 4mm to 30mm.

[0045] In this embodiment, the LED chip 2 is a flip-chip LED. Flip-chip LEDs have advantages such as high light extraction efficiency, good heat dissipation, high light output power per unit area, high reliability, low mass production cost, and ability to withstand high current driving. This makes it easy to mount the LED chip 2 and the driver IC 3 on the first side 11 of the substrate 1. At the same time, a single-sided aluminum substrate with low cost and strong heat dissipation capacity can be used instead of the traditional multi-layer substrate 1, thereby reducing the manufacturing cost of the LED backlight.

[0046] Reference Figure 6 As shown in the figure, in an embodiment of the present invention, an LED backlight includes a driver IC3 in each partition 111 on the substrate 1 of the LED backlight. The driver IC3 has four pins, one of which is an output channel. The output channel of the driver IC3 is connected to an LED chip 2. One driver IC3 controls the light emission of one LED chip 2, i.e., N=1, X=1.

[0047] Reference Figure 7 As shown, another LED backlight of the invention embodiment includes a driver IC3 in each partition 111 on the substrate 1 of the LED backlight. The driver IC3 has eight pins, four of which are output channels. Each output channel is connected to six LED chips 2. The six LED chips 2 can be connected to the output channels in series, parallel or mixed. One driver IC3 controls the light emission of twenty-four LED chips 2, i.e. N=4, X=6.

[0048] LED backlights are not limited to the LED backlights described above. As long as M, N, and X are greater than or equal to 1 and N is less than or equal to 6, the LED backlight can be flexibly configured with different numbers of driver IC3 channels and driver IC3 controlling different numbers of LED chips 2.

[0049] Reference Figure 8 As shown, the present invention also provides a method for manufacturing an LED backlight, used to manufacture the LED backlight in the embodiments, comprising the following steps:

[0050] S100. Provide a substrate 1 and a stencil 5, align the stencil 5 with the substrate 1, and then apply solder paste to the LED pads and IC pads of the substrate 1 simultaneously through the stencil 5, wherein the amount of solder paste on the LED pads and IC pads is different.

[0051] S200 provides LED chip 2 and driver IC 3 with a white appearance. The LED chip 2 and driver IC 3 are soldered onto the LED pad and IC pad respectively by reflow soldering to form an LED backlight.

[0052] Prior to step S200, the driver IC3 is encapsulated with white plastic to give it a white appearance. Specifically, the white plastic is one of epoxy resin, epoxy resin mixture, silicone resin, or polyimide filled with titanium dioxide as a whitening agent.

[0053] The present invention also provides another method for manufacturing an LED backlight, used to manufacture the LED backlight in the embodiments, comprising the following steps:

[0054] S100. Provide a substrate 1 and a stencil 5, align the stencil 5 with the substrate 1, and then apply solder paste to the LED pads and IC pads of the substrate 1 simultaneously through the stencil 5, wherein the amount of solder paste on the LED pads and IC pads is different.

[0055] S200 provides LED chip 2 and driver IC3. Reflow soldering is used to solder LED chip 2 and driver IC3 onto LED pads and IC pads respectively to form an LED backlight.

[0056] S300: The driver IC3 is coated with white adhesive, and the LED backlight with the driver IC3 is dried in an oven to give the driver IC3 a white appearance. Specifically, the white adhesive 4 is an epoxy resin or silicone resin containing titanium dioxide as a whitening agent. The white adhesive can be applied by dispensing, spraying, printing, etc.

[0057] In this embodiment, a plurality of first through holes 51 and second through holes 52 are spaced apart on the stencil 5. The first through holes 51 correspond to the positions of the LED pads, and the second through holes 52 correspond to the positions of the IC pads. The depth of the first through holes 51 is less than the depth of the second through holes 52. Because the depth of the first through holes 51 is less than the depth of the second through holes 52, when the squeegee applies the solder paste from the stencil 5 evenly to the LED pads and IC pads through the first through holes 51 and the second through holes 52, the amount of solder paste on the LED pads is less than the amount of solder paste on the IC pads.

[0058] Preferably, the stencil 5 has a first surface and a second surface, the first surface being a flat surface that fits against the first side surface 11, and the second surface being a concave-convex surface. Since the LED chip 2 is relatively small, it requires less solder paste during soldering, while the driver IC 3 is relatively large and requires more solder paste. By using stencils 5 of varying thicknesses, a single solder paste printing process and a single reflow soldering process can be employed to simultaneously apply solder paste, thereby meeting the different solder paste requirements on the LED pads and IC pads, and significantly shortening the manufacturing cycle of the LED backlight.

[0059] Specifically, the steel mesh 5 includes a mesh plate, on the side of the mesh plate facing away from the substrate 1, a boss 53 is provided, and a boss 53 is provided for each second through hole 52, with the second through hole 52 passing through the boss 53. By providing a boss 53 on the second through hole 52, that is, the second surface of the steel mesh 5 is a concave-convex surface, the depth of the first through hole 51 is less than the depth of the second through hole 52. Specifically, the height of the boss 53 is equal to the depth of the second through hole 52.

[0060] Preferably, the depth of the first through-hole 51 is 0.01 mm to 0.03 mm, and the depth of the second through-hole 52 is 0.05 mm to 0.1 mm. By controlling the depths of the first through-hole 51 and the second through-hole 52, different depths can be satisfied while facilitating the application of solder paste. When solder paste is applied to the second surface of the stencil 5, the squeegee can move smoothly on the stencil 5 to ensure that the solder paste is evenly adhered to the substrate 1.

[0061] In the description herein, it should be understood that the terms "above" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, and are not intended to 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 the present invention.

[0062] In the description of this specification, references to terms such as "an embodiment" indicate that a specific feature, structure, material, or characteristic associated with that embodiment is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0064] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A method of manufacturing an LED backlight, characterized by, A LED backlight source is manufactured, which comprises a substrate, LED chips and a driving IC, the substrate has a first side, the LED chips and the driving IC are both arranged on the first side, the first side is provided with M partitions, each of the partitions is provided with one driving IC and N channels, the driving IC controls X LED chips through one channel, wherein M, N and X are all integers greater than or equal to 1, and N is less than or equal to 6, the appearance of the driving IC is white; the driving IC is packaged by plastic sealing material, the plastic sealing material is white plastic; or the outer surface of the driving IC is coated with white glue. The manufacturing method of the LED backlight source comprises the following steps: S100, providing a substrate and a steel mesh, aligning the steel mesh with the substrate, and then coating tin paste on LED pads and IC pads of the substrate through the steel mesh, wherein the amount of tin paste on the LED pads and the IC pads is different; S200, providing LED chips and a driving IC with a white appearance, and welding the LED chips and the driving IC on the LED pads and the IC pads respectively by reflow soldering to form the LED backlight source.

2. The method of manufacturing an LED backlight of claim 1, wherein, The plastic sealing material contains a whitening agent, and the plastic sealing material is one of an epoxy resin, an epoxy resin mixture, a silicone resin or a polyimide.

3. The method of claim 1, wherein The white glue is an epoxy resin or a silicone resin.

4. The method of claim 1, wherein The center distance between adjacent LED chips is 4-30 mm.

5. The method of claim 1, wherein The LED chip is an LED flip chip.

6. The method of claim 1, wherein A plurality of first through holes and second through holes are arranged on the steel mesh, the first through holes correspond to the positions of the LED pads, the second through holes correspond to the positions of the IC pads, and the depth of the first through holes is less than that of the second through holes.

7. The method of claim 1, wherein The steel mesh comprises a mesh plate, a boss is arranged on the side of the mesh plate away from the substrate, one boss is arranged corresponding to each second through hole, and the second through hole penetrates the boss.

8. The method of claim 6, wherein the LED backlight is manufactured by: The depth of the first through hole is 0.01-0.03 mm, and the depth of the second through hole is 0.05-0.1 mm.

9. The method of claim 1, wherein Before step S200, the driving IC is plasticized by the white plastic.

10. The method of claim 1, wherein The following steps are further included: S300, the driving IC is coated with the white glue, and the LED backlight source provided with the driving IC is dried in an oven to form a white appearance.

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