Light-emitting element

Abstract

The invention discloses a light-emitting element, and the element comprises an LED chip which is provided with a first surface, a second surface opposite to the first surface, and a side wall connected with the first surface and the second surface. The wavelength conversion layer is at least arranged on the first surface of the LED chip; the electrode expansion structure is arranged on the second surface of the LED chip; the packaging layer at least surrounds the LED chip, the wavelength conversion layer and the electrode expansion structure; and at least one functional structure module selected from the group consisting of the following structure modules. The method can flexibly adapt to different application scenes.

Description

Technical Field

[0001] This invention relates to the field of light-emitting device technology, and more specifically, to a light-emitting element. Background Technology

[0002] Chip-scale packaging (CSP), as a lead-free technology, has its size directly determined by the chip size. When the chip size is small (e.g., less than 20*20mil), the limited electrode area of ​​the CSP package makes it prone to alignment misalignment and poor soldering during surface mount technology (SMT), leading to decreased placement yield and difficulty in improving placement efficiency. To improve placement reliability without introducing a lead frame, an enlarged pad structure is usually added to the lower end of the chip electrodes. This maintains the true CSP (lead-free) structure while improving placement yield and reducing costs, enabling efficient packaging applications for small-sized chips.

[0003] However, with the enlargement of pads and the miniaturization of package structures, the heat dissipation capacity of devices has become a key bottleneck restricting performance and reliability, urgently requiring further optimization and solutions. The relevant CSP package structures mainly suffer from the following technical problems: First, in terms of application adaptability, traditional CSP packaging structures are relatively simple and difficult to adapt to diverse application needs. Second, regarding heat dissipation performance, while the traditional enlarged pad structure improves surface mount reliability to some extent, unreasonable thermal conductivity configuration of the pad materials and unscientific heat dissipation path design lead to heat accumulation inside the chip, severely affecting the device's luminous efficacy and lifespan. Furthermore, in terms of current distribution, the limited electrode area of ​​small-sized chips makes it easy for current to accumulate near the electrodes, creating a current congestion effect. This not only reduces the chip's luminous uniformity but also leads to excessively high local temperatures, accelerating chip aging. Finally, in terms of reliability, traditional CSP packaging provides insufficient protection for the phosphor layer, especially for high-performance phosphor materials such as KSF that are sensitive to water and oxygen. The lack of effective protection measures results in rapid performance degradation of the device under high temperature and high humidity environments. Summary of the Invention

[0004] The purpose of this invention is to provide a light-emitting element that can be flexibly adapted to different application scenarios.

[0005] The embodiments of the present invention are implemented as follows: This application provides a light-emitting element, including: An LED chip has a first surface, a second surface opposite to the first surface, and a sidewall connecting the first surface and the second surface; A wavelength conversion layer is provided at least on the first surface of the LED chip; An electrode enlargement structure is disposed on the second surface of the LED chip; An encapsulation layer is disposed at least around the LED chip, the wavelength conversion layer, and the electrode enlargement structure; It also includes: at least one functional structural module selected from the group consisting of the following structural modules: (a) An upper electrode structure for enhancing the lateral spread of current and a lower electrode connecting the upper electrode structure and the electrode expansion structure disposed on the surface of the semiconductor light-emitting structure layer of the LED chip; (b) A high-voltage chip structure integrated inside the LED chip, consisting of multiple semiconductor light-emitting units connected in series via connecting electrodes; (c) A cup-shaped reflective structure surrounding the sidewall of the LED chip for controlling the light emission angle; (d) A protective functional layer covering the wavelength conversion layer, which has both light transmittance and environmental isolation.

[0006] In a possible implementation, the upper electrode structure includes a pad electrode and finger-like or mesh-like extensions extending outward from the pad electrode.

[0007] In a possible implementation, the area of ​​the upper electrode structure is larger than the area of ​​the lower electrode of the LED chip.

[0008] In a possible implementation, the ratio of the total projected area of ​​the electrode enlargement structure to the total projected area of ​​the lower electrode of the chip is 3 to 30.

[0009] In a possible implementation, the upper electrode in the high-voltage chip structure includes a connection electrode that connects to an adjacent chip.

[0010] In a possible implementation, the bowl-shaped reflective structure is made of a transparent material.

[0011] In a possible implementation, the protective functional layer includes light-scattering particles, which may include silicon dioxide or titanium dioxide.

[0012] In a possible implementation, the electrode expansion structure includes an upper expansion pad and a lower expansion pad with different thermal conductivity, wherein the thermal conductivity of the upper expansion pad is greater than that of the lower expansion pad; the thermal conductivity of the upper expansion pad is greater than 250 W / m·K, and the material of the upper expansion pad includes Cu or Cu alloy, with a Cu content of more than 90%.

[0013] In a possible implementation, the maximum projected area of ​​the light-emitting element in a horizontal direction is defined as follows: the projected area of ​​the encapsulation layer is S1, the projected area of ​​the upper enlarged pad is S2, the projected area of ​​the lower enlarged pad is S3, the projected area of ​​the LED chip is S4, and the projected area of ​​the lower electrode of the chip is S5, wherein S1>S2>S3>S4>S5. Wherein, the area ratio of the projected area S3 of the lower enlarged pad to the projected area S2 of the upper enlarged pad is 0.5~0.95, the area ratio of the projected area S5 of the lower electrode of the chip to the projected area S4 of the LED chip is 0.2~0.7, and the area ratio of the projected area S3 of the lower enlarged pad to the projected area S4 of the LED chip is 5~10. The projection of the lower enlarged pad is located within the projection range of the upper enlarged pad, and the distance Δ between the two is 20~50um.

[0014] In a possible implementation, the chip lower electrode includes a first lower electrode and a second lower electrode with different electrical properties, and a minimum distance d1 between the first lower electrode and the second lower electrode; The upper enlarged pad includes a first upper pad electrode and a second upper pad electrode with different electrical properties, and the minimum distance d2 between the first upper pad electrode and the second upper pad electrode; The lower enlarged pad includes a first lower pad electrode and a second lower pad electrode with different electrical properties, and the minimum distance d3 between the first lower pad electrode and the second lower pad electrode; Among them, d1 <d2<d3。

[0015] The beneficial effects of the embodiments of the present invention are: By providing four optional functional modules (a, b, c, d), the light-emitting element of this application is no longer a fixed product, but a customizable technology platform. Specifically, according to different end-application requirements (such as Mini LED displays requiring high uniformity, lighting requiring high driving voltage, focused lighting requiring narrow beams, and outdoor displays requiring high reliability), corresponding functional modules (a, b, c, d) can be selected and integrated, thereby quickly developing products with different performance focuses. This solves the problem of traditional CSP packaging structures being singular and unable to flexibly respond to market segmentation needs. Moreover, each optional module directly corresponds to a clear and key performance improvement direction.

[0016] For example, selecting the top electrode structure (a) directly targets and improves the current distribution uniformity of the LED chip, thereby enhancing luminous uniformity and luminous efficacy. Selecting the high-voltage chip structure (b) directly alters the device's fundamental electrical characteristics, increasing the operating voltage and reducing the drive current, thus simplifying the drive circuit and improving system energy efficiency. Selecting the cup-shaped reflector structure (c) directly controls the optical path, changing and optimizing the light emission angle and intensity distribution. Selecting the protective functional layer (d) directly enhances the device's ability to isolate itself from environmental factors such as moisture and oxygen, improving long-term reliability. This ensures that regardless of which module(s) are selected, predictable and significant performance improvements can be achieved in specific performance dimensions.

[0017] Furthermore, when introducing the aforementioned modular design, all modules are functional additions to the typical CSP architecture, which retains the LED chip, wavelength conversion layer, electrode expansion structure, and packaging layer. This means that while achieving the targeted performance improvements mentioned above, the solution still maintains the inherent advantages of CSP packaging, such as miniaturization, bracketless design, and high light density. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a longitudinal cross-sectional view of one embodiment of the light-emitting element of the present invention; Figure 2 This is a cross-sectional view of one embodiment of the light-emitting element of the present invention; Figure 3 This is a longitudinal cross-sectional view of an embodiment of the light-emitting element of the present invention, in which the stepped structure is shown; Figure 4 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 7 This is a schematic diagram of the structure of Embodiment 4 of the present invention; Figure 8 This is a comparison chart of experimental data for Model 1 and Model 2 in Embodiment 5 of the present invention; Figure 9 This is a comparison chart of experimental data for Model 1 of Embodiment 5 of the present invention; Figure 10 This is a comparison chart of experimental data for Model 2 of Embodiment 5 of the present invention.

[0020] Icons: 1. LED chip; 11. Semiconductor light-emitting unit; 111. N-type layer; 112. Light-emitting layer; 113. P-type layer; 114. Substrate; 2. Wavelength conversion layer; 31. Upper enlarged pad; 311. First upper pad electrode; 312. Second upper pad electrode; 32. Lower enlarged pad; 321. First lower pad electrode; 322. Second lower pad electrode; 4. Encapsulation layer; 5. Upper electrode structure; 51. Pad electrode; 52. Extension; 53. Connecting electrode; 6. High voltage chip structure; 7. Cup-shaped reflective structure; 8. Insulating layer; 9. Chip lower electrode; 91. First lower electrode; 92. Second lower electrode; 10. Protective functional layer; M1. Chip lower surface; M2. Chip upper surface; N. Stepped shape. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not 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 this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] refer to Figure 1 The light-emitting element of this application includes: an LED chip, a wavelength conversion layer, an electrode expansion structure, and a packaging layer. The LED chip has a first surface, a second surface opposite to the first surface, and a sidewall connecting the first and second surfaces; the wavelength conversion layer is disposed on the first surface of the LED chip, and can also be arranged to wrap around the top and outer sidewalls of the LED chip; the electrode expansion structure is disposed on the second surface of the LED chip; the packaging layer is disposed at least around the LED chip, the wavelength conversion layer, and the electrode expansion structure, which can fully protect the internal structure of the light-emitting element. In addition, the light-emitting element can be configured with functional structural modules with different functions. These functional structural modules can be selected from one or more of the following structural modules, and can be integrated according to different end-application requirements (such as Mini LED displays requiring high uniformity, lighting requiring high driving voltage, focused lighting requiring narrow beams, outdoor displays requiring high reliability, etc.), thereby quickly developing products with different performance focuses. This solves the problem that the traditional CSP packaging structure is single and cannot flexibly respond to market segmentation needs. Moreover, each optional module directly corresponds to a clear and key performance improvement direction.

[0028] Furthermore, when introducing the aforementioned modular design, all modules are functional additions to the typical CSP architecture, which retains the LED chip, wavelength conversion layer, electrode expansion structure, and packaging layer. This means that while achieving the targeted performance improvements mentioned above, the solution still maintains the inherent advantages of CSP packaging, such as miniaturization, bracketless design, and high light density.

[0029] The following examples illustrate the use of different structural modules.

[0030] Example 1 like Figures 1 to 7As shown, this embodiment provides a light-emitting element with an upper electrode structure 5, which is more suitable for Mini LED display applications and can effectively solve the current expansion problem of miniaturized chips.

[0031] The upper electrode structure 5 is disposed on the surface of the semiconductor light-emitting structure layer of the LED chip 1, and includes a pad electrode 51 and finger-shaped or grid-shaped extensions 52 extending outward from the pad electrode 51. In Mini LED applications, the area of ​​the upper electrode is usually small, and the upper electrode is used to increase the current spreading effect. The pad electrode 51 is electrically connected to the semiconductor light-emitting structure layer through an opening in the insulating layer 8, and the finger-shaped extensions 52 adopt a fine pattern design with a width of 5-20 μm and a spacing of 10-30 μm.

[0032] In flip-chip ODR products and Ag mirror products, the area of ​​the upper electrode is larger, such as larger than the area of ​​the lower electrode 9 on the chip, in order to increase the uniformity of current spread. In this case, the upper electrode structure 5 is actually an electrode pattern covering a large area.

[0033] By extending the current laterally from the electrode contact point to the entire chip area through the upper electrode, the current density distribution becomes more uniform, effectively avoiding current congestion and improving the chip's luminous uniformity. At the same time, it increases the chip's maximum withstand current density, significantly improving the chip's luminous efficiency and lifespan.

[0034] In practical applications, the ratio of the total projected area of ​​the upper electrode structure 5 to the total projected area of ​​the lower electrode 9 is preferably 3 to 30. This ratio range ensures good current spreading while avoiding excessively large electrode areas that could affect light extraction efficiency.

[0035] Example 2 like Figures 1 to 3 and Figure 5 As shown, the light-emitting element provided in this embodiment has a high-voltage chip structure 6, which is suitable for application scenarios that require high operating voltage, such as linear drive lighting systems.

[0036] The high-voltage chip structure 6 is integrated inside the LED chip 1 and includes multiple independent semiconductor light-emitting units 11. Each unit contains a complete N-type layer 111, a light-emitting layer 112, and a P-type layer 113. The N-type layer 111 is connected to the substrate 114. Adjacent units are isolated by deep trenches and filled with an insulating medium. Units are connected in series through connecting electrodes 53. Depending on different voltage requirements, chip structures containing 2, 3, 4, or more light-emitting units can be designed to achieve operating voltages such as 6V, 9V, and 12V.

[0037] By integrating multiple cascaded light-emitting units within the chip, the operating voltage is significantly increased while the drive current is reduced. For example, connecting three 3V operating units in series to achieve a 9V operating voltage reduces the drive current to one-third of the original at the same power, significantly reducing ohmic losses and improving overall energy efficiency. Simultaneously, the high-voltage operating mode reduces the number of external electrodes, providing greater flexibility in pad design and facilitating optimized heat dissipation path design.

[0038] Example 3 like Figures 1 to 3 and Figure 6 As shown, the light-emitting element provided in this embodiment has a cup-shaped reflective structure 7. This structure is suitable for applications that require special control over the light emission angle, such as spotlights and projectors.

[0039] The bowl-shaped reflective structure 7 is disposed around the sidewall of the LED chip 1, and has an inverted trapezoidal or parabolic shape. The sidewall of the bowl-shaped structure forms an angle of 45-60° with the bottom surface of the chip. The bowl-shaped structure is made of transparent silicone material, in which TiO2, SiO2, or Al2O3 reflective particles are uniformly dispersed. The particle concentration is controlled at 30%-50% by volume, and the particle size is distributed in the range of 0.5-5μm.

[0040] The sidewall of the cup can efficiently reflect the light emitted from the side of the chip to the light-emitting direction, significantly improving the light distribution characteristics of the device, enhancing the uniformity of the color temperature spatial distribution, and significantly improving color consistency.

[0041] In practical applications, the depth of the cup structure is typically 1.5-3 times the chip thickness, and the sidewall angle is optimized based on the target beam angle. For applications requiring a narrow beam, a smaller sidewall angle (e.g., 45°) is used; for applications requiring a wide beam, a larger sidewall angle (e.g., 60°) is used.

[0042] Example 4 like Figures 1 to 3 and Figure 7 As shown, the light-emitting element provided in this embodiment has a protective functional layer 10. This structure is particularly suitable for applications with high reliability requirements, such as automotive displays and outdoor displays.

[0043] The protective functional layer 10 covers the wavelength conversion layer 2, has a thickness of 20-100 μm, and is composed of highly transparent silicone and scattering particles. The light transmittance of the protective functional layer 10 is greater than 95%, and the water vapor transmittance is less than 1×10⁻⁶. - ³ g / m²·day, preferably less than 5×10 -4 g / m²·day. The protective functional layer 10 needs to have excellent heat resistance, UV resistance and mechanical strength to ensure effective protection of the internal fluorescent layer in various harsh environments.

[0044] This structure can effectively isolate water vapor and oxygen in the environment, protecting sensitive fluorescent materials such as KSF from erosion. At the same time, the addition of scattering particles can expand the light-emitting angle, achieving a better light mixing effect and improving color uniformity.

[0045] In a preferred embodiment, an appropriate amount of phosphor can also be added to the protective functional layer 10 to form a remote fluorescence structure, further improving color consistency and light efficiency.

[0046] Example 5 The light-emitting element of this embodiment has a stepped pad structure for optimizing the heat dissipation effect.

[0047] The electrode expansion structure includes an upper expanded pad 31 and a lower expanded pad 32, forming a stepped structure. Define the maximum projected area of the light-emitting element in a horizontal direction. The projected area of the encapsulation layer 4 is S1; the projected area of the upper expanded pad 31 is S2; the projected area of the lower expanded pad 32 is S3; the projected area of the LED chip 1 is S4; the projected area of the chip lower electrode 9 is S5. The areas satisfy the relationship: S1 > S2 > S3 > S4 > S5.

[0048] In a preferred embodiment, the area ratio of the projected area S3 of the lower expanded pad 32 to the projected area S2 of the upper expanded pad 31 is 0.5 to 0.95, preferably 0.6 to 0.85. The area ratio of the projected area S5 of the chip lower electrode 9 to the projected area S4 of the LED chip 1 is 0.2 to 0.45 or 0.45 to 0.7. The area ratio of the projected area S2 of the upper expanded pad 31 to the projected area S5 of the chip lower electrode 9 is 3 to 30. The area ratio of the area S1 of the encapsulation layer 4 to the area S4 of the LED chip 1 is 1.5 to 15, preferably 2 to 10. The area ratio of the projected area S3 of the lower expanded pad to the projected area S4 of the LED chip is 5 to 10, preferably 5.7 to 8.0.

[0049] In terms of the spacing design, the chip lower electrode 9 includes a first lower electrode 91 and a second lower electrode 92 with different electrical properties, and the minimum spacing between them is d1; the upper expanded pad 31 includes a first upper pad electrode 311 and a second upper pad electrode 312 with different electrical properties, and the minimum spacing between them is d2; the lower expanded pad 32 includes a first lower pad electrode 321 and a second lower pad electrode 322 with different electrical properties, and the minimum spacing between them is d3; where d1 < d2 < d3. The difference between d3 and d2 is 30 to 300 μm, preferably 50 to 250 μm.

[0050] The preferred ranges for specific parameters are: d1 is 20~150um, preferably 60~100um; d2 is 80~200um, preferably 80~150um; d3 is 120~350um, preferably 150~300um. The projection of the lower enlarged pad is located within the projection range of the upper enlarged pad, and the distance Δ between them is 20~50um.

[0051] Regarding material selection, the thermal conductivity of the lower electrode 9 and the upper expanded pad electrode is greater than 250 W / m·K (at room temperature of 20°C), preferably greater than 280 W / mK, and includes high thermal conductivity metal materials such as Cu. The upper expanded pad material is Cu or a Cu alloy, with a Cu content of more than 90% and a thermal conductivity greater than 350 W / mK. The lower expanded pad material is Sn or a Sn alloy, with a thickness of 1µm to 100µm, preferably 10-40µm, and is a Sn pad or a gold-tin alloy pad. The lower expanded pad material may also include Cu / Ni / Au, where the Cu thickness is 1µm to 100µm, preferably 10-40µm; the Ni thickness is 0.5 to 10µm, preferably 1.5 to 3µm; and the Au thickness is 200A to 5000A, preferably 500 to 1000A. This structure provides better heat dissipation for the pad.

[0052] In this embodiment, two different sizes of LED chip products were selected for testing, and the specific parameters are shown in Table 1.

[0053]

[0054] Table 1 A push-pull force testing machine was used to test the thrust of two types of samples: Bare die: The raw chip without enlarged pads; Enlarged pad LED: An LED chip packaged with an enlarged pad structure.

[0055] Each sample group was tested at 10 points, and the thrust value (unit: N) was recorded.

[0056] The test structure for Model 1 is as follows Figure 8 and Figure 9 As shown in the table, the test structure for Model 2 is as follows. Figure 8 and Figure 10 As shown.

[0057] By comparing the thrust data of bare die and LED chips with expanded pads, we can see that: The average thrust of the enlarged pad structure of Model 1 is approximately 2.35 times that of bare die; the average thrust of the enlarged pad structure of Model 1 is approximately 1.91 times that of bare die.

[0058] Experimental results show that the enlarged pad structure of this embodiment can significantly improve the mechanical strength and reliability of chip soldering, making it suitable for high-reliability packaging applications.

[0059] Example 6 This embodiment provides a light-emitting element, a high-reliability Mini LED device for automotive displays, which also employs an upper electrode structure 5 and a protective functional layer 10, combined with an optimized stepped pad structure.

[0060] Based on the upper electrode structure 5 of Embodiment 1, this device adds the protective functional layer 10 of Embodiment 4 and adopts the stepped pad design of Embodiment 5. The specific structure includes: the LED chip 1 adopts a flip-chip structure, a finger-shaped upper electrode is fabricated on the upper surface of the chip, a KSF fluorescent film is placed above the chip as a wavelength conversion layer 2, and the outermost layer is covered with a protective functional layer 10 containing SiO2 scattering particles. The electrode expansion structure adopts a stepped design with Cu upper pads and Sn lower pads, and the area ratio and spacing parameters of each layer are configured according to the optimal range.

[0061] The upper electrode ensures the uniformity of current spread of the Mini LED chip 1, while the protective functional layer 10 provides excellent moisture resistance, meeting the high reliability requirements of the automotive environment.

[0062] In practical applications, the device also exhibits excellent heat dissipation performance, with the chip junction temperature controlled below 85°C under maximum operating current, ensuring long-term reliability.

[0063] Example 7 This embodiment provides a light-emitting element, a high-voltage LED device for focused lighting, which adopts a high-voltage chip structure 6 and a cup-shaped reflective structure 7, combined with an optimized heat dissipation design.

[0064] Based on the high-voltage chip structure 6 of Embodiment 2, this device integrates the cup-shaped reflective structure 7 of Embodiment 3 and adopts the stepped pad design of Embodiment 5. Specifically, it uses a 9V high-voltage chip containing three cascaded light-emitting units, which are connected to the enlarged pads via flip-chip bonding. The chip sidewalls surround the cup-shaped reflective structure 7, and it is finally packaged through the encapsulation layer 4. The upper enlarged pad 31 is made of high thermal conductivity Cu material with a thermal conductivity greater than 350 W / m·K, and the lower enlarged pad 32 is made of SnAg alloy for easy soldering.

[0065] High-voltage chips reduce driving requirements, and the cup structure provides precise beam control, making it particularly suitable for lighting applications that require high brightness and narrow beams, such as spotlights and projectors.

[0066] Example 8: One light-emitting element in this embodiment includes an encapsulation layer 4. The encapsulation layer 4 includes a first encapsulation layer 4 surrounding the sidewalls and bottom of the LED chip 1 and the wavelength conversion layer 2, and a second encapsulation layer 4 surrounding the sidewalls of the enlarged pad structure. The first encapsulation layer 4 and the second encapsulation layer 4 have high reflectivity, and the material is such as high-reflectivity white glue.

[0067] In some embodiments, a protective functional layer 10 may also be provided, which needs to be both light-transmitting and moisture-proof, so as to protect the wavelength conversion layer 2 (such as the KSF fluorescent film layer) from moisture erosion while ensuring light transmission. Under certain circumstances, reflective particles, such as SiO2 and TiO2, may be added to the protective functional layer 10 to increase the light dissipation angle.

[0068] Furthermore, the first encapsulation layer 4 is preferably a high-reflectivity silicone with a reflectivity greater than 95%, wherein TiO2, SiO2, or Al2O3 reflective particles are dispersed therein. In addition to high reflectivity, the second encapsulation layer 4 also needs to have good mechanical strength and adhesion to ensure the stability of the pad structure. The protective functional layer 10 needs to balance light transmittance, moisture resistance, and mechanical properties, and is typically made of addition-cure silicone or epoxy resin modified materials.

[0069] Through the design of a multi-layered packaging structure, an optimal balance is achieved between optical performance, environmental reliability, and mechanical strength. Reliability is significantly improved while maintaining high luminous efficiency.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A light-emitting element, characterized in that, include: An LED chip has a first surface, a second surface opposite to the first surface, and a sidewall connecting the first surface and the second surface; A wavelength conversion layer is provided at least on the first surface of the LED chip; An electrode enlargement structure is disposed on the second surface of the LED chip; An encapsulation layer is disposed at least around the LED chip, the wavelength conversion layer, and the electrode enlargement structure; It also includes: at least one functional structural module selected from the group consisting of the following structural modules: (a) An upper electrode structure for enhancing the lateral spread of current and a lower electrode connecting the upper electrode structure and the electrode expansion structure disposed on the surface of the semiconductor light-emitting structure layer of the LED chip; (b) A high-voltage chip structure integrated inside the LED chip, consisting of multiple semiconductor light-emitting units connected in series via connecting electrodes; (c) A cup-shaped reflective structure surrounding the sidewall of the LED chip for controlling the light emission angle; (d) A protective functional layer covering the wavelength conversion layer, which has both light transmittance and environmental isolation.

2. The light-emitting element according to claim 1, characterized in that, The upper electrode structure includes a pad electrode and finger-shaped or mesh-shaped extensions extending outward from the pad electrode.

3. The light-emitting element according to claim 1, characterized in that, The area of ​​the upper electrode structure is larger than the area of ​​the lower electrode of the LED chip.

4. The light-emitting element according to claim 2 or 3, characterized in that, The ratio of the total projected area of ​​the electrode enlargement structure to the total projected area of ​​the lower electrode of the chip is 3 to 30.

5. The light-emitting element according to claim 1, characterized in that, The upper electrode in the high-voltage chip structure includes a connecting electrode that connects to adjacent chips.

6. The light-emitting element according to claim 1, characterized in that, The bowl-shaped reflective structure is made of transparent material.

7. The light-emitting element according to claim 1, characterized in that, The protective functional layer contains light-scattering particles, which include silicon dioxide or titanium dioxide.

8. The light-emitting element according to claim 1, characterized in that, The electrode expansion structure includes an upper expansion pad and a lower expansion pad with different thermal conductivity, and the thermal conductivity of the upper expansion pad is greater than that of the lower expansion pad; the thermal conductivity of the upper expansion pad is greater than 250 W / m·K, and the material of the upper expansion pad includes Cu or Cu alloy, with a Cu content of more than 90%.

9. The light-emitting element according to claim 8, characterized in that, The maximum projected area of ​​the light-emitting element in a horizontal direction is defined as follows: the projected area of ​​the encapsulation layer is S1, the projected area of ​​the upper enlarged pad is S2, the projected area of ​​the lower enlarged pad is S3, the projected area of ​​the LED chip is S4, and the projected area of ​​the lower electrode of the chip is S5, where S1 > S2 > S3 > S4 > S5. Wherein, the area ratio of the projected area S3 of the lower enlarged pad to the projected area S2 of the upper enlarged pad is 0.5~0.95, the area ratio of the projected area S5 of the lower electrode of the chip to the projected area S4 of the LED chip is 0.2~0.7; the area ratio of the projected area S3 of the lower enlarged pad (32) to the projected area S4 of the LED chip is 5~10; The projection of the lower enlarged pad is located within the projection range of the upper enlarged pad, and the distance Δ between the two is 20~50um.

10. The light-emitting element according to claim 9, characterized in that, The chip lower electrode includes a first lower electrode and a second lower electrode with different electrical properties, and the minimum distance d1 between the first lower electrode and the second lower electrode; The upper enlarged pad includes a first upper pad electrode and a second upper pad electrode with different electrical properties, and the minimum distance d2 between the first upper pad electrode and the second upper pad electrode; The lower enlarged pad includes a first lower pad electrode and a second lower pad electrode with different electrical properties, and the minimum distance d3 between the first lower pad electrode and the second lower pad electrode; Where d1 < d2 < d3.

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