LED packaging structure

Abstract

The utility model relates to the technical field of semiconductor packaging, and provides an LED packaging structure. The LED packaging structure at least comprises an LED chip which is provided with a first surface and a second surface which are oppositely arranged; the fluorescent layer is arranged above the first surface of the LED chip, and the fluorescent layer covers the first surface of the LED chip; the lens is arranged on the surface of one side, far away from the LED chip, of the fluorescent layer and completely covers the surface of one side, far away from the LED chip, of the fluorescent layer; the light blocking layer is arranged around the LED chip and the fluorescent layer; the thickness of the light blocking layer is larger than the sum of the thickness of the LED chip and the thickness of the fluorescent layer. The thickness of the light blocking layer exceeding the fluorescent layer is larger than or equal to 1 / 3 of the thickness of the lens. By adopting the LED packaging structure, the concentration ratio of a beam angle can be improved, side light emission is reduced, and the resolution ratio of a single LED lamp bead is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor packaging, particularly relates to a LED packaging structure. BACKGROUND

[0002] In the application of light emitting diode (LED chip), in order to realize high concentration light source or matrix light source, single side light or no side light packaging mode is used in packaging. For this, the existing support type packaging is to fix blue light chip on the bowl cup base of packaging support through die bonding glue, connect blue light chip and support through bonding wire material, fill the mixture of fluorescent powder and silica gel in the bowl cup of packaging support, and white light is generated by exciting fluorescent powder through blue light chip, and then white light emitting device is obtained.

[0003] The deficiency of the existing support type packaging scheme is that it is suitable for the packaging of low-power chips, has poor heat dissipation, the connection by bonding wire material makes the circuit reliability poor, cannot meet the market demand in large-size LED packaging, and the light emitting angle of the packaged product is large and the concentration is poor.

[0004] Therefore, in the packaging of large-size, large-power and other LEDs, how to improve the light emitting concentration and brightness of LED products while ensuring the packaging performance has become one of the technical problems to be solved by the technical personnel in the field. SUMMARY

[0005] To solve the deficiencies of the LED packaging structure in the prior art, the utility model provides a LED packaging structure, which can realize single-side concentrated light emission of LED devices, improve the light emitting concentration of LED devices and improve the brightness and resolution of LED devices.

[0006] To achieve at least one of the advantages or other advantages, the utility model provides a LED packaging structure, at least comprising: LED chip, having oppositely arranged first surface and second surface;Fluorescent layer, set above the first surface of LED chip, the fluorescent layer covers the first surface of LED chip;Lens, set on the surface of the fluorescent layer away from the LED chip, and completely covers the surface of the fluorescent layer away from the LED chip;Light barrier layer, at least surrounding the four sides of LED chip and fluorescent layer;Wherein, the thickness of light barrier layer is greater than the sum of the thickness of LED chip and fluorescent layer;The thickness of the light barrier layer beyond the fluorescent layer is greater than or equal to 1 / 3 of the thickness of the lens.

[0007] In some embodiments, the thickness of the light barrier layer beyond the fluorescent layer is less than 1 / 2 of the thickness of the lens.

[0008] In some embodiments, the thickness of the light barrier layer beyond the fluorescent layer is less than 2 / 3 of the thickness of the lens.

[0009] In some embodiments, the projection area of the fluorescent layer is greater than the projection area of the LED chip as viewed from above.

[0010] In some embodiments, the projection area of the lens is greater than or equal to the projection area of the fluorescent layer as viewed from above.

[0011] In some embodiments, the fluorescent layer and the lens are made of the same material; the refractive index of the fluorescent layer is greater than or equal to the refractive index of the lens.

[0012] In some embodiments, the thickness of the lens is greater than or equal to 1.5 times the thickness of the fluorescent layer.

[0013] In some embodiments, the light blocking layer is made of black silicone, black filler added thermosetting EMC, black filler added thermoplastic PCT or PPA. The light blocking layer is doped with light reflecting particles.

[0014] In some embodiments, the angle of the lens is less than or equal to 90°.

[0015] In some embodiments, the LED packaging structure further comprises conductive pillars, at least two of which are arranged on the second surface of the LED chip.

[0016] The LED packaging structure provided by the present application has at least the following advantages compared with the existing corresponding LED chip packaging structure:

[0017] 1. In the LED packaging structure, the light blocking layer is arranged on the four sides of the LED chip and the fluorescent layer and the side surface of the lens part region, so that the emitted light around the LED chip is reflected to the lens and emitted, the side light emission is reduced, and the concentration of the beam angle is improved, and the resolution and recognition rate of a single LED are improved.

[0018] 2. In the LED packaging structure, the lens structure is arranged above the light emitting surface of the LED chip, and the angle of the lens is less than or equal to 90°, so that the emitted light is more concentrated, and the concentration of the beam angle is improved, and it is suitable for high concentration light source field.

[0019] 3. The LED packaging structure without support and gold wire can be used for packaging small size LED and is suitable for matrix light source field. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0021] Figure 1 is a cross-sectional structure schematic view of an embodiment of the LED packaging structure in the utility model;

[0022] Figure 2 is Figure 1 a dimension marking schematic view;

[0023] Figure 3 is Figure 1 a light emission schematic view of the LED packaging structure shown in the utility model;

[0024] Figure 4 is a top view structure schematic view of the light emission surface of the LED packaging structure in the utility model.

[0025] Reference signs: 100-LED packaging structure, 10-LED chip, 10a-first surface, 10b-second surface, 20-fluorescent layer, 30-lens, 40-light blocking layer, H1~H5-thickness, L1 / L2-distance. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the protection scope of the utility model.

[0027] In the description of the utility model, it is understood that the orientation or position relationship indicated by the terms "center", "transverse", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or component must have a particular orientation or be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included one or more features. In the description of the utility model, unless otherwise specified, the meaning of "multiple" is two or more. In addition, the term "includes" and any variation thereof means "at least includes".

[0028] In the description of the utility model, need explanation, unless another explicit provision and limitation, term " install " " link " " connection " should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integral connection;Can be mechanical connection, also can be electrical connection;Can be direct connection, also can be indirectly connected through intermediate medium, can be two components inside the intercommunication. For ordinary skilled in the art, the above-mentioned terms can be understood in the utility model with the concrete meaning of the specific circumstances.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0030] Please refer to Figure 1 and Figure 2 , Figure 1 is a cross-sectional structure schematic view of an embodiment of the LED packaging structure in the utility model, Figure 2 is a size marking schematic view of Figure 1 To achieve at least one of the advantages or other advantages, an embodiment of the utility model provides a kind of LED packaging structure 100, at least includes: LED chip 10, the fluorescent layer 20 being arranged above LED chip 10, the lens 30 being arranged above fluorescent layer 20, and the photoresist layer 40 being arranged in the partial area of the circumferential surface of LED chip 10, fluorescent layer 20 and lens 30.Light blocking layer 40 The thickness is greater than the sum of the thickness of LED chip 10 and fluorescent layer 20;The thickness of light blocking layer 40 beyond fluorescent layer is greater than or equal to 1 / 3 of the thickness of lens 30.It needs to be explained that generally, LED chip array on wafer is packaged once on wafer, and then cut into single LED chip grain.Embodiment and drawing are shown and described with the packaging structure of single LED chip grain.

[0031] As Figure 1As shown, the LED chip 10 has a first surface 10a and a second surface 10b arranged oppositely. In the vertical direction, the first surface 10a of the LED chip 10 is defined as the upper side, and the second surface 10b of the LED chip 10 is defined as the lower side. The structure of the LED chip 10 is not the focus of the present application and will not be described here. In the illustrated embodiment, the LED chip 10 is a flip structure. The second surface 10b of the LED chip 10 is provided with an electrode, and the LED chip 10 is electrically connected to the PCB or the substrate provided with a conductive circuit through the electrode. As shown in the figure Figure 1 As shown, the second surface 10b of the LED chip 10 is provided with a conductive column 50. Two (two) conductive columns 50 are arranged on the lower side of the second surface 10b of the LED chip 10, and the LED chip 10 is electrically connected to the PCB or the substrate provided with a conductive circuit through the two conductive columns 50. The material of the conductive column 50 can be metal, such as copper, tin, silver, etc., which can improve the efficiency and stability of the installation and connection of the conductive column 50 under the premise of ensuring good conductivity of the conductive column 50.

[0032] The fluorescent layer 20 is arranged on the upper side of the first surface 10a of the LED chip 10. The fluorescent layer 20 completely covers the first surface 10a of the LED chip 10. The fluorescent layer 20 will not cover the peripheral side of the LED chip 10. The flip LED chip 10 is a cuboid or a square, and the peripheral side refers to the four sides between the first surface 10a and the second surface 10b, that is, the four side light emitting surfaces of the LED chip 10. It can be understood that the fluorescent layer 20 will not cover the four side light emitting surfaces of the LED chip 10.

[0033] Optionally, the fluorescent layer 20 is a prefabricated fluorescent film or fluorescent film. The fluorescent film or fluorescent film can be prefabricated according to the required size, and then attached to the first surface 10a of the LED chip 10. The fluorescent layer 20 can adjust the light color of the LED chip 10, and can also effectively prevent the heat transfer of the LED chip 10 to improve the light emitting efficiency.

[0034] In some embodiments, the fluorescent layer 20 is a fluorescent film (PIS) made of fluorescent powder and silica gel. The fluorescent powder can be of different colors, so that the packaged LED device emits light of the corresponding color. When the LED chip array on the wafer is packaged at one time on the entire wafer, the fluorescent film can be fixed on the first surface 10a of the LED chip 10. In this way, the consistency of the fluorescent powder can be improved, thereby improving the yield of packaging and manufacturing. At the same time, the planar fluorescent film (fluorescent layer 20) is attached to the light emitting surface (the first surface 10a in the figure) of the LED chip 10, which is convenient to operate, reduces the cost of labor and equipment, and reduces the overall cost of packaging.

[0035] The lens 30 is arranged on the surface of the fluorescent layer 20 away from the LED chip 10 and is located above the fluorescent layer 20. In the illustrated example, the lens 30 completely covers the surface of the fluorescent layer 20 away from the flip-chip LED chip 10. In some embodiments, the lens 30 can be formed on the fluorescent layer 20 by molding. The lens 30 is a silica gel lens. The silica gel lens can be a spherical lens, a semi-spherical lens, a planar lens, etc. The silica gel lens is easy to manufacture and has good airtightness and thermal stability, and the LED chip 10 has a relatively high use power. In addition, the silica gel lens can be used in molds of different specifications, thereby forming silica gel lenses of different requirements and reducing production costs.

[0036] According to different actual requirements of the LED packaging structure 100, the lens 30 can have different angles, diameters, thicknesses, etc. The angle of the lens 30 is less than or equal to 90°. With this angle, the light distribution of the light emitted through the lens 30 is relatively concentrated. The smaller the angle of the lens 30, the smaller the light emitting angle of the LED packaging structure 100 and the higher the light concentration. According to different use requirements of the LED packaging structure 100, different lens 30 molds can be used in the manufacturing process to obtain lenses 30 of different angles. For example, the angle of the lens 30 can be 30°, 45°, 60°, 75°, or 90°. In actual production, different molds can be used on the fluorescent layer 20 to manufacture lenses 30 of different angles to form different beam angles and meet the optical requirements of different LED devices according to different actual requirements of the LED device.

[0037] Preferably, the material of the lens 30 is consistent with the material of the fluorescent layer 20 to avoid scattering of the light source of the LED chip 10 in different media between the fluorescent layer 20 and the lens 30, thereby reducing the light intensity of the packaged LED device. When the material of the lens 30 is silica gel, the material of the fluorescent layer 20 is high-refractive glue and fluorescent powder, which can increase the adhesion strength and refractive index of the fluorescent layer 20 and the lens 30, thereby improving the light intensity and stability of the packaged LED device.

[0038] The refractive index of the fluorescent layer 20 is greater than or equal to the refractive index of the lens 30. When the light emitted from the first surface 10a of the LED chip 10 changes from a high-refractive layer to a low-refractive layer from the fluorescent layer 20 to the lens 30, the total reflection proportion of the emitted light in the fluorescent layer 20 and the lens 30 can be improved, the light intensity of the light emitting surface in the lens 30 can be increased, and the light brightness of the LED device can be improved. In some embodiments, the refractive index of the fluorescent layer 20 is 1.44-1.6, and the refractive index of the lens 30 is 1.35-1.44. When the refractive indices of the fluorescent layer 20 and the lens 30 are both 1.44, the refractive indices can be used as the boundary between the fluorescent layer 20 and the lens 30.

[0039] The light blocking layer 40 at least surrounds the LED chip 10 and the fluorescent layer 20. The light blocking layer 40 does not cover the light emitting area of the first surface 10a of the LED chip 10. The light blocking layer 40 surrounds the part of the lens 30 close to the fluorescent layer 20. The light blocking layer 40 is made of light-proof material. For example, the material of the light blocking layer 40 can be black silicone, black filler added thermosetting EMC (epoxy resin molding material), black filler added thermoplastic PCT (poly1,4-cyclohexylene dimethylene terephthalate) & PPA (polyphthalamide). The light blocking layer 40 can be made by injection molding.

[0040] The light blocking layer 40 is doped with light reflecting particles, so that the layer has the characteristics of high reflectivity (reflectivity is at least greater than 90%), and the material is a high molecular material doped with high reflection particles, and the light reflecting particles include but are not limited to titanium dioxide (TiO2) powder, silicon dioxide (SiO2) powder, etc., and the high molecular material includes but is not limited to epoxy resin, silicone, etc. That is, the light blocking layer 40 is made of light-proof high reflection material, in order to block or prevent the light of the LED chip 10 from emitting from the side (four side light emitting surfaces), increase the light intensity and brightness of the front light (the first surface 10a of the LED chip 10 in the figure), and further increase the recognition of the forward light source. In practical application, the thickness, material, doping amount of light reflecting particles of the light blocking layer 40 surrounding the LED chip 10 and the fluorescent layer 20 can be freely adjusted based on the reflectivity of the final light blocking layer 40.

[0041] When the LED chip 10 array on the wafer is packaged at one time on the whole wafer, the light blocking layer 40 is used to block different LED chips 10, which can effectively prevent the side light of the LED chip 10, reduce the mutual influence between different LED chip 10 light sources, and further improve the recognition of the single LED chip 10 product.

[0042] The thickness of the light blocking layer 40 is greater than the sum of the thicknesses of the LED chip 10 and the fluorescent layer 20, so as to completely block the side light emitting surface around the LED chip 10, and make the light emit from the preset light emitting surface (the first surface 10a of the LED chip 10 in the figure) as much as possible. Figure 1 Referring to Figure 2In the cross-sectional structure diagram of the LED packaging structure 100, the thickness (or height) of the LED chip 10 is denoted as H1, the thickness of the fluorescent layer 20 is denoted as H2, the thickness of the lens 30 is denoted as H3, and the thickness of the light-blocking layer 40 is denoted as H4, where H4>H1+H2. The thickness of the light-blocking layer 40 beyond the fluorescent layer 20 is denoted as H5, and H5=H4-H1-H2. The thickness of the light-blocking layer 40 beyond the fluorescent layer 20 is greater than or equal to 1 / 3 of the thickness of the lens 30, i.e., H5≥H3*1 / 3. The thickness (or height) of the light-blocking layer 40 beyond the fluorescent layer 20 is greater than the thickness of the fluorescent layer 20 and extends to the partial outer peripheral area of the lens 30, which can further reduce the light-emitting angle, reduce the side light emission, increase the light reflection of the side surface, and reduce the mutual interference between different LED chip light sources, as shown in Figure 3

[0043] In some embodiments, the thickness of the light-blocking layer 40 beyond the fluorescent layer 20 is less than 1 / 2 of the thickness of the lens 30, i.e., H5≦H3*1 / 2.

[0044] In some embodiments, the thickness of the light-blocking layer 40 beyond the fluorescent layer 20 is less than 2 / 3 of the thickness of the lens 30, i.e., H5≦H3*2 / 3.

[0045] The upper limit of the relationship between the thickness H5 of the light-blocking layer 40 beyond the fluorescent layer 20 and the thickness H3 of the lens 30 is set to avoid excessive shielding of the lens 30 by the light-blocking layer 40, which affects the light-emitting quantity and light intensity of the LED packaging structure 100, thereby reducing the brightness of the LED device.

[0046] The thickness of the lens 30 is greater than or equal to 1.5 times the thickness of the fluorescent layer 20, i.e., H3≥H2*1.5. In other words, the thickness ratio of the lens 30 to the fluorescent layer 20 is greater than or equal to 1.5, i.e., H3:H2≥1.5. In this way, the light-emitting angle can be reduced, and the concentration of light emission can be improved. In some embodiments, the thickness of the fluorescent layer 20 is 80 microns to 120 microns, and the thickness of the lens 30 is 120 microns to 300 microns.

[0047] In combination with Figure 1 and Figure 2 Referring to Figure 4 , viewed from above the first surface 10a of the LED chip 10, the cross sections of the LED chip 10 and the fluorescent layer 20 respectively have a quadrilateral structure. The cross section of the fluorescent layer 20 is greater than the cross section of the LED chip 10, which can form full coverage of the first surface 10a of the LED chip 10, thereby ensuring that the first surface 10a of the LED chip 10 can achieve full light emission. Furthermore, the cross section of the fluorescent layer 20 is greater than the cross section of the LED chip 10, which can prevent the LED chip 10 from being offset to cause light leakage, thereby ensuring the uniformity of the light color of the LED packaging structure 100. ​

[0048] In some embodiments, as Figure 2 and Figure 4 , along the horizontal direction, the distance between the outer periphery of the LED chip 10 and the outer periphery of the fluorescent layer 20 is L1 and L2, respectively, wherein L1≥20 microns and L2≥20 microns. In this way, the light emitted by the LED chip 10 can fully excite the fluorescent layer 20, thereby improving the light efficiency.

[0049] As shown in FIG. 4, as viewed from above the first surface 10a of the LED chip 10, the projection area of the lens 30 is greater than or equal to the projection area of the fluorescent layer 20, ensuring that the light emitted by the LED chip 10 in the forward direction (as shown in the figure, from above the first surface 10a of the LED chip 10) can be completely emitted through the lens 30, thereby improving the concentration of the emitted light and the recognition of the LED device product. In the illustrated embodiment, the lens 30 is hemispherical, and the projection area of the circular face in the hemisphere is greater than or equal to the projection area of the fluorescent layer 20.

[0050] Compared with the existing LED packaging structure that emits white light, the LED packaging structure provided by the present application can be applied in the field of high-concentration LED light sources and matrix light sources, and at least has the following advantages: (1) In the LED packaging structure, the light blocking layer is arranged on the four sides of the LED chip and the fluorescent layer and the side surface of the lens part, so that the light emitted around the LED chip is reflected to the lens for emission, reducing the side light emission, thereby improving the concentration of the beam angle and the resolution and recognition rate of the single LED. (2) In the LED packaging structure, the lens structure is arranged above the light emitting surface of the LED chip, and the angle of the lens is less than or equal to 90°, so that the emitted light is more concentrated, thereby improving the concentration of the beam angle and being suitable for the field of high-concentration light sources. (3) The LED packaging structure without support and gold wire can be applied to small-size LED packaging (such as the smallest 150μm*150μm), can be used for vehicle matrix light source, and can be used as a high-resolution light source for intelligent control. (4) By adjusting the angle of the lens and the height of the light blocking layer around the four sides, the overall light emission angle of the LED packaging structure can be adjusted, and the light emission effect of the LED light source using the LED packaging structure described in the present application can be used as a laser light source. Further, it can be used as a low-cost version of a laser light source. Laser light source has the requirements of monochromaticity, directivity, safety, stability, etc. According to the actual demand, monochromatic LED light source (RGB) and transparent silicone fluorescent film are selected to realize monochromatic light and monochromaticity. The small-angle lens can improve the beam concentration of the LED light source, thereby realizing the directivity of the LED light source. The energy density of the LED is lower than that of the laser light source, and it is safer than the laser light source. The service life of the LED is long, and the stability in high temperature and high humidity environment is better than that of the general laser light source.

[0051] Finally, it should be noted that: the above embodiments are used to illustrate the technical solutions of the present application, but not limited to them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An LED package structure, characterized in that, At least comprising: an LED chip, having a first surface and a second surface arranged oppositely; a fluorescent layer, arranged above the first surface of the LED chip, covering the first surface of the LED chip; a lens, arranged on the surface of the fluorescent layer away from the LED chip, and covering the surface of the fluorescent layer away from the LED chip completely; a light blocking layer, at least surrounding the LED chip and the fluorescent layer; wherein the thickness of the light blocking layer is greater than the sum of the thicknesses of the LED chip and the fluorescent layer; the thickness of the light blocking layer beyond the fluorescent layer is greater than or equal to 1 / 3 of the thickness of the lens.

2. The LED package structure of claim 1, wherein, The thickness of the light blocking layer beyond the fluorescent layer is less than 1 / 2 of the thickness of the lens.

3. The LED package structure of claim 1, wherein, The thickness of the light blocking layer beyond the fluorescent layer is less than 2 / 3 of the thickness of the lens.

4. The LED package structure of claim 1, wherein, Viewing from above the LED chip, the projected area of the fluorescent layer is greater than the projected area of the LED chip.

5. The LED package structure of claim 1, wherein, Viewing from above the LED chip, the projected area of the lens is greater than or equal to the projected area of the fluorescent layer.

6. The LED package structure of claim 1, wherein, The material of the fluorescent layer is the same as that of the lens; the refractive index of the fluorescent layer is greater than or equal to the refractive index of the lens.

7. The LED package structure of claim 1, wherein, The thickness of the lens is greater than or equal to 1.5 times the thickness of the fluorescent layer.

8. The LED package structure of claim 1, wherein, The material of the light blocking layer is black silicone, thermosetting EMC with black fillers, thermoplastic PCT or PPA with black fillers; the light blocking layer is doped with light reflecting particles.

9. The LED package structure of claim 1, wherein, The angle of the lens is less than or equal to 90°.

10. The LED package structure of claim 1, wherein, The LED packaging structure further comprises conductive pillars, at least two of which are arranged on the second surface of the LED chip.

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