LED light board and manufacturing method thereof

Abstract

The present invention is applicable to the field of LED technology and provides an LED light board, comprising a substrate, the substrate being provided with a circuit layer, the circuit layer having solder pads for connecting to a plurality of LED chips; the circuit layer being provided with a first reflective layer, the first reflective layer being provided with a plurality of window structures, the window structures being arranged in an array and each of the window structures having at least one pair of solder pads for connecting to the LED chips; the LED light board also comprising a second reflective layer filled between the first reflective layer and the LED chips, the reflectivity of the second reflective layer being greater than the reflectivity of the first reflective layer. The present invention also provides a method for manufacturing an LED light board. The LED light board and its manufacturing method provided by the present invention facilitate die bonding, improve light efficiency, increase process yield, and have low production costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of LEDs, and in particular relates to an LED lamp panel and a manufacturing method thereof. Background Art

[0002] LED backlight panels can achieve local dimming, which greatly improves display quality and is favored by the market. In the existing technology, LED backlight panels based on glass substrates need to coat a layer of white ink on the glass substrate and make a window treatment at the location where the LED chip is placed to expose the solder pad to facilitate soldering of the LED chip to the solder pad (i.e., solid crystal). The window treatment of white ink will have a great impact on the luminous efficiency of the backlight panel. If the window is too large (will expose the glass substrate), the light emitted by the LED will be lost through the glass. If the window is too small, the ink will cover the solder pad and cause poor solid crystal. At the same time, the reflectivity of white ink is generally not high. The luminous efficiency of LED backlight panels has always been limited by the reflectivity of white ink, resulting in relatively low luminous efficiency of LED backlight panels, which is not conducive to improving the backlight brightness. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an LED lamp panel and a manufacturing method thereof, which are beneficial to crystal bonding, improve light efficiency, increase backlight brightness, and have low manufacturing cost.

[0004] The technical solution of the present invention is: an LED lamp board, a circuit layer is provided on the substrate, the circuit layer has a soldering pad for connecting to the LED chip; a first reflective layer is provided on the circuit layer, the first reflective layer is provided with a plurality of window structures, each window structure has at least one pair of soldering pads in the area corresponding to the window structure, the LED chip is provided in the window structure and connected to the soldering pads in the corresponding window structure, and an accommodating area is formed between the outer peripheral side of the LED chip and the inner peripheral side of the window structure; the LED light board also includes a second reflective layer filled in the accommodating area.

[0005] As a further improvement of the present technical solution, the second light reflecting layer is made of silicone or silicone resin, and light reflecting particles are dispersed on the second light reflecting layer.

[0006] As a further improvement of the present technical solution, the second reflective layer is formed by dispensing glue in the window structure.

[0007] As a further improvement of the present technical solution, the LED chip is a flip chip, and there is a gap between the side of the LED chip facing the substrate and the substrate; the second reflective layer includes a side reflective portion connected to the outer peripheral side of the LED chip and a bottom reflective portion filling the gap.

[0008] As a further improvement of the present technical solution, a solder paste layer is provided on the surface of the solder pad, the solder paste layer is used to connect with the LED chip, and the second reflective layer covers the solder paste layer.

[0009] As a further improvement of the present technical solution, the top surface of the first light reflecting layer is between the bottom surface and the top surface of the LED chip, and the top surface of the second light reflecting layer is not higher than the top surface of the first light reflecting layer.

[0010] As a further improvement of the present technical solution, the reflectivity of the second light reflecting layer is greater than the reflectivity of the first light reflecting layer.

[0011] As a further improvement of the present technical solution, the first reflective layer is made of white ink.

[0012] As a further improvement of the present technical solution, the thickness of the first light reflecting layer ranges from 20 microns to 80 microns.

[0013] As a further improvement of the present technical solution, the dimensions of the window structure satisfy the following relationship:

[0014] Bx<Px,By<Py;

[0015] Wherein, Bx represents the maximum horizontal dimension of the window structure, By represents the maximum vertical dimension of the window structure, Px represents the horizontal spacing between two adjacent LED chips, and Py represents the vertical spacing between two adjacent LED chips.

[0016] As a further improvement of the present technical solution, the window structure is a rectangular through hole, and the length of the rectangular through hole is ≥2 mm.

[0017] The present invention also provides a method for manufacturing an LED light board, which is used to manufacture the above-mentioned LED light board, comprising the steps of:

[0018] preparing a substrate;

[0019] Disposing a circuit layer having a pad on the substrate;

[0020] Disposing a first light reflecting layer formed of a first light reflecting material on the circuit layer;

[0021] Arrange a plurality of window structures on the first light reflecting layer, so that there is at least one solder pad in the area of ​​each window structure;

[0022] Placing an LED chip in the window structure and connecting the LED chip to the solder pad;

[0023] A second light reflecting material is filled into the window structure, and the second light reflecting material is located between the first light reflecting layer and the LED chip to form a second light reflecting layer.

[0024] The present invention provides an LED light board and a manufacturing method thereof, wherein the circuit layer is provided with a first light-reflecting layer, the first light-reflecting layer is provided with a plurality of window structures, each window structure has at least one solder pad in the area corresponding to the window structure, the LED chip is provided in the window structure and connected to the solder pad corresponding to the window structure, and an accommodating area is formed between the outer periphery of the LED chip and the inner periphery of the window structure. By filling the accommodating area with a second light-reflecting layer, it is facilitated to solidify the crystal, and the manufacturing cost is low. The present invention provides an LED light board and a manufacturing method thereof, which not only facilitates solidification of the crystal, but also improves the light efficiency, helps to increase the backlight brightness, and improves the process yield, and the manufacturing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a structural diagram of a substrate in an LED light board provided by an embodiment of the present invention;

[0027] Figure 2 This is a schematic structural diagram of a circuit layer printed on a substrate in an LED light board provided by an embodiment of the present invention;

[0028] Figure 3 This is a schematic structural diagram of a first reflective layer coated on a circuit layer in an LED light board provided by an embodiment of the present invention;

[0029] Figure 4 This is a structural schematic diagram of an LED light panel provided by an embodiment of the present invention in which a first reflective layer is provided with a window structure;

[0030] Figure 5 This is a schematic diagram of the structure of an LED chip soldered to a solder pad in an LED lamp board provided by an embodiment of the present invention;

[0031] Figure 6 This is a structural diagram of an LED light panel provided by an embodiment of the present invention, in which a second reflective material is used to fill the accommodating area;

[0032] Figure 7 This is a schematic structural diagram of an LED light board provided by an embodiment of the present invention;

[0033] Figure 8 This is a top view of an LED light panel provided by an embodiment of the present invention;

[0034] Figure 9 This is another top view of an LED light panel provided by an embodiment of the present invention.

[0035] Numbers in the figure:

[0036] 1-LED chip; 3-circuit layer; 4-first reflective layer, 41-window structure, 410-accommodation area; 5-second reflective layer, 50-second reflective material, 51-side reflective portion, 52-bottom reflective portion; 6-substrate; 7-solder paste layer. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] It should be noted that the terms "setting" and "connecting" should be understood in a broad sense. For example, it can be directly setting or connecting, or it can be indirectly setting or connecting through a central component or a central structure.

[0039] In addition, if there are terms such as "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating orientation or positional relationships in the embodiments of the present invention, they are based on the orientation or positional relationships shown in the drawings or the conventional placement state or usage state, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure, feature, device or element referred to must have a specific orientation or positional relationship, nor must it be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0040] The various specific technical features and embodiments described in the specific implementation methods can be combined in any suitable manner unless there is any contradiction. For example, different implementation methods can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the specific technical features / embodiments in the present invention will not be described separately.

[0041] like Figures 7 to 9 As shown, an embodiment of the present invention provides an LED light board, including a substrate and an LED chip 1. In this embodiment, the substrate is a glass substrate 6 (such as Figure 1As shown), the substrate is provided with a circuit layer 3, that is, a circuit layer 3 is provided on the surface of the glass substrate 6, the LED chip 1 is provided with multiple, and the circuit layer 3 has at least one pair of pads (as shown Figure 2 ), used to connect with the plurality of LED chips 1; a first reflective layer 4 (as shown) is provided on the circuit layer 3 Figure 3 As shown), the lower surface of the first reflective layer 4 covers the circuit layer 3, and the first reflective layer 4 is provided with a plurality of window structures 41 (as shown Figure 4 The window structure 41 is a hole that passes through the first reflective layer 4. The LED chip 1 is arranged in the window structure 41 (as shown). Figure 5 As shown), and connected to the soldering pads in the corresponding window structures 41, the window structures 41 in this embodiment are arranged in an array, and the window area of ​​the window structure 41 is larger than the projected area of ​​the LED chip 1 on the glass substrate 6, exposing the position on the surface of the glass substrate 6 where the LED chip 1 needs to be soldered, and making it easy for the LED chip 1 to be placed in the window structure 41, that is, the window structure 41 is set to expose the soldering pad, thereby avoiding the soldering pad being covered by the first reflective layer 4, and facilitating the soldering of the LED chip 1 in the window structure 41 with the corresponding soldering pad. If the gap between the window structure 41 and the LED chip 1 is too small, it will be inconvenient to install. If the gap is too large, it will easily leak light and affect the light effect and the process yield. Since the size of the window structure 41 is larger than the outer size of the LED chip 1, an accommodating area 410 is formed between the outer peripheral side of the LED chip 1 and the inner peripheral side of the window structure 41. The LED lamp board also includes a second reflective layer 5, which is filled in the accommodating area 410 (as shown in FIG. Figure 6 As shown, the second light-reflecting layer 5 is filled in the window structure 41. The second light-reflecting layer 5 is located above the circuit layer 3 and on the outer periphery of the LED chip 1. The second light-reflecting layer 5 is tightly fitted to the outer periphery of the LED chip 1 and the inner periphery of the window structure 41. The size of the window structure 41 is larger than that of the LED chip 1, making it easy to place the LED chip 1 in the window structure 41. This has high production efficiency and low production cost, which helps ensure the yield rate of die bonding. Moreover, the second light-reflecting layer 5 formed by filling can well fill the accommodating area 410, avoiding light leakage gaps. The LED light board provided by the embodiment of the present invention is conducive to die bonding and improves light efficiency, with high production efficiency and low production cost.

[0042] Furthermore, the reflectivity of the second light-reflecting layer 5 is greater than that of the first light-reflecting layer 4. The reflectivity of the second light-reflecting layer 5 is higher than that of the first light-reflecting layer 4. The second light-reflecting layer 5 with a higher reflectivity reflects more effective light and has a higher luminous efficiency, that is, the light effect is improved.

[0043] Furthermore, the top surface of the first reflective layer 4 is between the bottom surface and the top surface of the LED chip 1, and the top surface of the second reflective layer 5 is not higher than the top surface of the first reflective layer 4. The thickness of the first reflective layer 4 can range from 20 microns to 80 microns. In specific applications, the second reflective layer 5 is filled in the accommodating area 410 between the LED chip 1 and the first reflective layer 4, that is, filled in the window structure 41, and the top surface of the second reflective layer 5 can be lower than the top surface of the first reflective layer 4, or remain flush with the top surface of the first reflective layer 4. In this embodiment, the second reflective layer 5 is formed by solidifying the colloid. The colloid has a certain fluidity and a good filling effect, which avoids the occurrence of undesirable phenomena such as lack of glue and the existence of light leakage gaps. The thickness of the first reflective layer 4 is a (such as Figure 3 As shown), the thickness of the second light reflecting layer 5 is c (as shown Figure 7 As shown), in order to prevent the colloid from overflowing onto the upper surface of the first reflective layer 4, it is necessary to control the amount of glue forming the second reflective layer 5 so that the thickness c of the second reflective layer 5 is ≤ the thickness a of the first reflective layer 4, thereby preventing the colloid of the second reflective layer 5 from overflowing onto the first reflective layer 4, which is beneficial to ensuring the consistency of the light effect of the LED light board. The value range of a can be 20 microns to 80 microns, preferably, a is 25 microns to 60 microns, and more preferably, a is 50 microns to 60 microns.

[0044] Furthermore, the dimensions of the window structure 41 satisfy the following relationship: Bx<Px, By<Py; wherein Bx represents the maximum horizontal dimension of the window structure, By represents the maximum vertical dimension of the window structure, Px represents the horizontal spacing between two adjacent LED chips 1, and Py represents the vertical spacing between two adjacent LED chips 1. In a specific application, the window structure 41 is rectangular, and its maximum dimension is the length of the rectangle, such as Figure 9 As shown, the window structure 41 can be a rectangular groove, the shape of the LED chip 1 can be rectangular, and the pitch value (Pitch) between the centers of two adjacent LED chips 1 is p (as shown in FIG. Figure 8 、 Figure 9 As shown), the lateral center distance between two adjacent LED chips 1 is Px and the longitudinal center distance is Py, the maximum lateral dimension of the window structure 41 is Bx and the maximum longitudinal dimension is By (as shown Figure 7 As shown), Bx<Px, By<Py. The accommodation area 410 may be in the shape of a “U”, and the length dimension of the rectangle Bx≥2mm, preferably, Bx≥3mm. In another embodiment, as Figure 8 As shown, the window structure 41 may also be in the shape of a circular hole, in which case its maximum size is its diameter, and the diameters are smaller than Px and Py.

[0045] Furthermore, the LED chip 1 can be a flip chip, and there is a gap between the side of the LED chip 1 facing the glass substrate 6 and the glass substrate 6. The second reflective layer 5 includes a side reflective portion 51 and a bottom reflective portion 52. The side reflective portion 51 is connected to the outer peripheral side of the LED chip 1, and the bottom reflective portion 52 fills the gap and is connected to the bottom surface of the LED chip 1.

[0046] Furthermore, a solder paste layer 7 is provided on the surface of the solder pad, and the metal solder paste of the solder paste layer 7 is gray and absorbs blue light. The LED chip 1 is connected to the solder pad through the solder paste layer 7, forming the above-mentioned gap filled by the bottom reflective portion 52. The solder paste layer 7 is used to connect with the LED chip 1. Specifically, the solder paste is printed on the solder pad, and the LED chip 1 is soldered to the solder pad to complete the solidification. The top surface of the first reflective layer 4 is between the bottom and top surfaces of the LED chip 1. The first reflective layer 4 is higher than the top surface of the LED chip 1 and will block light. The first reflective layer 4 is lower than the bottom surface of the LED chip 1 so that the solder paste layer 7 is exposed. In this embodiment, the LED chip 1 is connected to the solder pad through the solder paste layer 7 (metal solder paste). The metal solder paste is gray. The bottom reflective portion 52 located at the bottom of the LED chip 1 can be covered with the metal solder paste layer 7 to prevent blue light from being absorbed by the solder paste layer 7.

[0047] Furthermore, the first light reflecting layer 4 can be made of white ink. The second light reflecting layer 5 is made of silica gel or silicone resin, and light reflecting particles are dispersed in the second light reflecting layer 5 . In a specific application, the second reflective layer 5 contains at least one of TiO2 reflective particles and BaSO4 reflective particles, that is, a certain amount of reflective particles is mixed into the glue, which helps to further improve the reflectivity of the second reflective layer 5. The reflective layer of the LED light board can be made of a combination of white ink and white glue. Both white glue and white ink can be used as reflective materials: white ink is low in cost, but has low reflectivity and poor fluidity, making it suitable for large-area printing; white glue is expensive, has high reflectivity and strong fluidity, and is generally used for local gap dispensing in the prior art. In this embodiment, the first reflective layer 4 is made of white oil (white ink) and is low in cost, while the second reflective layer 5 is made of white glue, which has good fluidity and good filling effect. The reflectivity of the first reflective layer 4 is generally not higher than 93%, while the reflectivity of the second reflective layer 5 is not less than 98%. The problems of difficult die bonding, low light efficiency, and high cost are solved at the same time. In traditional methods, easy die bonding, high light efficiency, and low cost are conflicting constraints, and at least one of them must be sacrificed, making it impossible to achieve easy die bonding, high light efficiency, and cost while taking into account both. The LED lamp board provided by the present invention realizes easy crystal bonding and improved lighting efficiency, and has high efficiency and low cost. It ensures easy crystal bonding and high lighting efficiency while taking cost into account. It is highly operational in actual production and has high market application value.

[0048] An embodiment of the present invention further provides a method for manufacturing an LED light board, the method being used to manufacture the above-mentioned LED light board, comprising the steps of:

[0049] like Figure 1 As shown, a substrate is prepared. In this embodiment, a glass substrate 6 is used, which has good stability and low cost.

[0050] like Figure 2 As shown, a circuit layer 3 with solder pads is provided on the substrate. Specifically, the circuit layer 3 is printed on the substrate. The circuit layer 3 has solder pads for connecting with a plurality of LED chips 1 .

[0051] like Figure 3 As shown, a first light reflecting layer 4 formed of a first light reflecting material is provided on the circuit layer 3 ; specifically, in this embodiment, the first light reflecting layer 4 is formed by printing white ink on the circuit layer 3 .

[0052] like Figure 4 As shown, a plurality of window structures 41 are provided on the first light reflecting layer 4, so that there is at least one pair of pads in the region of each window structure 41; specifically, in this embodiment, the window structures 41 are formed by an exposure and etching process. The first light reflecting layer 4 is provided with a plurality of window structures 41 arranged in a matrix. In this embodiment, the window structures 41 are rectangular slots (such as Figure 7 In another embodiment, the window structure 41 may also be in the shape of a circular hole (as shown in FIG. Figure 8 shown).

[0053] like Figure 5 As shown, the LED chip 1 is arranged in the window structure 41, and the LED chip 1 is connected to the soldering pad; specifically, the soldering pad corresponding to the same LED chip 1 is also located in the window structure 41, that is, the LED chip 1 located in the window structure 41 is connected to the corresponding soldering pad, and two or more LED chips 1 can also be arranged in each window structure 41.

[0054] like Figure 6 As shown, a second reflective material 50 (in this embodiment, the reflectivity of the second reflective material 50 is greater than that of the first reflective material) is filled in the window structure 41, and the second reflective material 50 is located between the first reflective layer 4 and the LED chip 1 to form a second reflective layer 5. Figure 7 Specifically, in this embodiment, the second reflective material 50 is made of white glue.

[0055] An embodiment of the present invention provides an LED light board and a manufacturing method thereof. The circuit layer 3 is provided with a first reflective layer 4, which is provided with multiple window structures 41. The LED chip 1 is disposed within the window structures 41 and connected to corresponding solder pads within the window structures 41. An accommodating area 410 is formed between the outer periphery of the LED chip 1 and the inner periphery of the window structures 41. Filling the accommodating area 410 with a second reflective layer 5 having a higher reflectivity facilitates die bonding and reduces manufacturing costs. The reflectivity of the second reflective layer 5 is greater than that of the first reflective layer 4, thereby improving luminous efficiency. The LED light board and manufacturing method provided by the present invention not only facilitates die bonding but also improves luminous efficiency, increases process yield, and reduces manufacturing costs.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An LED light board, comprising a substrate and an LED chip, characterized in that: The substrate is provided with a circuit layer, the circuit layer having a solder pad for connecting to the LED chip; the circuit layer is provided with a first light reflecting layer, the first light reflecting layer is provided with a plurality of window structures, each window structure has at least one pair of solder pads in the area corresponding to the window structure, the LED chip is arranged in the window structure and connected to the solder pads in the corresponding window structure, and an accommodating area is formed between the outer periphery of the LED chip and the inner periphery of the window structure; the LED light board also includes a second light reflecting layer filling the accommodating area; A solder paste layer is provided on the surface of the solder pad, which is used to connect to the LED chip. The second reflective layer covers the solder paste layer. The second reflective layer contains at least one of TiO2 reflective particles and BaSO4 reflective particles. The reflectivity of the second reflective layer is greater than the reflectivity of the first reflective layer. The reflectivity of the first reflective layer is not higher than 93%, and the reflectivity of the second reflective layer is not less than 98%.

2. The LED light board according to claim 1, characterized in that: The second light reflecting layer is made of resin, and light reflecting particles are dispersed on the second light reflecting layer.

3. The LED light board according to claim 2, characterized in that: The second light reflecting layer is formed by dispensing glue in the window structure.

4. The LED light board according to claim 1, characterized in that: The LED chip is a flip chip, and there is a gap between the side of the LED chip facing the substrate and the substrate; the second reflective layer includes a side reflective portion connected to the outer peripheral side of the LED chip and a bottom reflective portion filling the gap.

5. The LED light board according to any one of claims 1 to 4, characterized in that: The top surface of the first light reflecting layer is between the bottom surface and the top surface of the LED chip, and the top surface of the second light reflecting layer is not higher than the top surface of the first light reflecting layer.

6. The LED light board according to claim 1, characterized in that: The first light reflecting layer is made of white ink.

7. The LED light board according to claim 1, characterized in that: The thickness of the first light reflecting layer ranges from 20 microns to 80 microns.

8. The LED light board according to claim 1, characterized in that: The dimensions of the window structure satisfy the following relationship: Bx<Px,By<Py; Wherein, Bx represents the maximum horizontal dimension of the window structure, By represents the maximum vertical dimension of the window structure, Px represents the horizontal spacing between two adjacent LED chips, and Py represents the vertical spacing between two adjacent LED chips.

9. The LED light board according to claim 1, wherein: The window structure is a rectangular through hole, and the length of the rectangular through hole is ≥2mm.

10. A method for manufacturing an LED light board, characterized in that: The manufacturing method is used to manufacture the LED light board according to any one of claims 1 to 9, comprising the steps of: preparing a substrate; Disposing a circuit layer having a pad on the substrate; Disposing a first light reflecting layer formed of a first light reflecting material on the circuit layer; Arrange a plurality of window structures on the first light reflecting layer, so that there is at least one solder pad in the area of ​​each window structure; Placing an LED chip in the window structure and connecting the LED chip to the solder pad; A second light reflecting material is filled into the window structure, and the second light reflecting material is located between the first light reflecting layer and the LED chip to form a second light reflecting layer.

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