Light emitting device

Abstract

The application relates to a light-emitting device. The light-emitting device comprises a base, a light-emitting chip, a first wavelength conversion layer and an encapsulation layer. The base has a mounting groove, and the light-emitting chip is arranged in the mounting groove. The first wavelength conversion layer covers the front surface of the light-emitting chip, the edge thickness of the first wavelength conversion layer is greater than the center thickness, and the edge thickness is the maximum thickness. The encapsulation layer is arranged in the mounting groove, surrounds the light-emitting chip and the first wavelength conversion layer, and covers at least the side surface of the light-emitting chip. By arranging the edge thickness of the first wavelength conversion layer to be greater than the center thickness and the edge thickness to be the maximum thickness, the quantity of wavelength conversion particles at the edge position of the first wavelength conversion layer is increased, the problem of poor wavelength conversion effect at the edge position is improved, and the original color light-emitting leakage is reduced or avoided.

Description

Technical Field

[0001] This application relates to the field of semiconductor light-emitting technology, and in particular to a light-emitting device. Background Technology

[0002] To change the color of light emitted by an LED chip, a wavelength conversion adhesive layer is typically applied. For example, a phosphor layer is applied to a blue LED chip to convert blue light into white light. The wavelength conversion adhesive layer is usually applied to the LED chip using a dispensing method. Located on the front side of the chip, the adhesive flows and cures under gravity, forming the wavelength conversion adhesive layer. Because the adhesive in the wavelength conversion adhesive diffuses more easily than the wavelength conversion particles within it, while the particles tend to accumulate in the center due to friction, the wavelength conversion effect at the edges of the adhesive layer is poor. This results in leakage of the original color of light, such as when a blue LED chip emits light, causing blue light to leak out and appear bluish. Summary of the Invention

[0003] Therefore, it is necessary to provide a light-emitting device to address the problem of poor wavelength conversion effect at the edge of the wavelength conversion adhesive layer.

[0004] A light-emitting device, comprising:

[0005] A base having a mounting groove;

[0006] A light-emitting chip, wherein the light-emitting chip is disposed in the mounting slot;

[0007] A first wavelength conversion layer covers the front side of the light-emitting chip, and the edge thickness of the first wavelength conversion layer is greater than the center thickness, which is the maximum thickness; and

[0008] An encapsulating adhesive layer is disposed in the mounting groove, surrounding the light-emitting chip and the first wavelength conversion layer, and at least covering the side of the light-emitting chip.

[0009] In one embodiment, the thickness of the first wavelength conversion layer gradually increases from the center to the edge; or the front side of the first wavelength conversion layer includes a central region and a surrounding region, the central region being planar and the surrounding region being arranged around the central region and gradually expanding away from the light-emitting chip.

[0010] In one embodiment, the front side of the first wavelength conversion layer is curved, and the side side of the first wavelength conversion layer is convex.

[0011] In one embodiment, the light-emitting device further includes a second wavelength conversion layer that covers the front side of the first wavelength conversion layer.

[0012] In one embodiment, the front side of the second wavelength conversion layer is either planar or concave curved.

[0013] In one embodiment, the front surface of the second wavelength conversion layer is curved; the front surface of the first wavelength conversion layer is curved, and the curvature of the front surface of the first wavelength conversion layer is greater than the curvature of the front surface of the second wavelength conversion layer.

[0014] In one embodiment, the light-emitting device further includes: wires connecting the electrodes on the front side of the light-emitting chip and the pads on the base, respectively; wherein the encapsulating adhesive layer covers the wires but does not cover the front side of the outermost structure on the light-emitting chip.

[0015] In one embodiment, the encapsulating adhesive layer is a reflective adhesive layer, or the encapsulating adhesive layer is a thermally conductive adhesive layer.

[0016] A light-emitting device, comprising:

[0017] substrate;

[0018] A light-emitting chip, wherein the light-emitting chip is disposed on the substrate;

[0019] A first wavelength conversion layer covers the front side of the light-emitting chip, and the edge thickness of the first wavelength conversion layer is greater than the center thickness, which is the maximum thickness; and

[0020] The lens is sealed and connected to the substrate, forming a cavity between the lens and the substrate, and the light-emitting chip and the first wavelength conversion layer are both located in the cavity.

[0021] In one embodiment, the thickness of the first wavelength conversion layer gradually increases from the center to the edge; or the front side of the first wavelength conversion layer includes a central region and a surrounding region, the central region being planar and the surrounding region being arranged around the central region and gradually expanding away from the light-emitting chip.

[0022] The aforementioned light-emitting device improves the problem of poor wavelength conversion effect at the edge position by setting the edge thickness of the first wavelength conversion layer to be greater than the center thickness, and the edge thickness to be the maximum thickness, thereby increasing the number of wavelength conversion particles at the edge position of the first wavelength conversion layer and reducing or avoiding the leakage of the original color light emission. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of the light-emitting device in the first embodiment of this application.

[0024] Figure 2for Figure 1 A schematic diagram of the molding process of the first wavelength conversion layer in a light-emitting device.

[0025] Figure 3 This is a cross-sectional view of the light-emitting device in the second embodiment of this application.

[0026] Figure 4 This is a cross-sectional view of the light-emitting device in the third embodiment of this application.

[0027] Figure 5 This is a cross-sectional view of the light-emitting device in the fourth embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100-Light-emitting device; 110-Base; 111-Mounting groove; 112-Substrate; 113-Damage; 114-Insulating part; 115-First metal part; 116-Second metal part; 120-Light-emitting chip; 130-First wavelength conversion layer; 131-Wavelength conversion adhesive; 132-Mold; 133-Convex surface; 134-Intermediate region; 135-Surrounding region; 140-Encapsulating adhesive layer; 150-Wire; 160-Second wavelength conversion layer; 170-Substrate; 180-Lens; 182-Support part; 184-Optical part; 186-Gap space; 190-Cavity;

[0030] th1 - edge thickness; th2 - center thickness. Detailed Implementation

[0031] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0032] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 application.

[0033] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0036] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0037] Please see Figure 1 , Figure 1A cross-sectional view of a light-emitting device according to a first embodiment of this application is shown. The light-emitting device 100 provided in one embodiment includes a base 110, a light-emitting chip 120, a first wavelength conversion layer 130, and an encapsulating adhesive layer 140. The base 110 has a mounting groove 111. The light-emitting chip 120 is disposed in the mounting groove 111. The first wavelength conversion layer 130 covers the front side of the light-emitting chip 120, and the edge thickness th1 of the first wavelength conversion layer 130 is greater than the center thickness th2, and is the maximum thickness. The encapsulating adhesive layer 140 is disposed in the mounting groove 111, surrounding the light-emitting chip 120 and the first wavelength conversion layer 130, and at least covers the side surface of the light-emitting chip 120.

[0038] By setting the edge thickness th1 of the first wavelength conversion layer 130 to be greater than the center thickness th2, and setting the edge thickness th1 to be the maximum thickness, the number of wavelength conversion particles at the edge of the first wavelength conversion layer 130 is increased, thereby improving the problem of poor wavelength conversion effect at the edge and reducing or avoiding leakage of the original color's light emission.

[0039] It should be noted that the center thickness th2 of the first wavelength conversion layer 130 is the thickness at the location where the optical axis of the light-emitting chip 120 passes, and the edge thickness th1 is the thickness of the front edge of the first wavelength conversion layer 130. The front edge of the first wavelength conversion layer 130 corresponds to the front edge of the light-emitting chip 120 and can cover the entire front of the light-emitting chip 120. The front of the first wavelength conversion layer 130 is its surface facing away from the light-emitting chip 120.

[0040] The base 110 includes a base 112 and a dam 113 disposed on the base 112, the dam 113 and the base 112 enclosing each other to form a mounting groove 111. The light-emitting chip 120 is disposed on the base 112 and located in the mounting groove 111. In other embodiments, the base 110 may be replaced by a reflective cup or a bowl-shaped cup.

[0041] Furthermore, the substrate 112 is a metal plate, which includes an insulating portion 114, a first metal portion 115, and a second metal portion 116. The insulating portion 114 is disposed between the first metal portion 115 and the second metal portion 116, thereby isolating the first metal portion 115 and the second metal portion 116 from each other. Compared with a resin substrate, the substrate 112 has a simpler structure, better heat dissipation, and a thinner thickness.

[0042] The light-emitting chip 120 can be, but is not limited to, LED chips, and there can be one or more of them. When there are multiple LED chips, they can be LED chips of different colors. The LED chips can be vertical chips or flip chips.

[0043] In this embodiment, the light-emitting chip 120 is a vertical chip, and the light-emitting device 100 further includes wires 150. The wires 150 connect the electrodes on the front side of the light-emitting chip 120 and the pads on the base 110, respectively. That is, the light-emitting chip 120 is die-bonded onto the first metal portion 115, and its front electrode is connected to the second metal portion 116 through the wires 150. In an alternative embodiment, the light-emitting chip 120 can be a flip chip, and its positive and negative electrodes on the back side are directly soldered onto the first metal portion 115 and the second metal portion 116, without the need for wire bonding.

[0044] The thickness of the first wavelength conversion layer 130 gradually increases from the center to the edge, meaning the thickness of the first wavelength conversion layer 130 gradually increases from the inside to the outside. Theoretically, the greater the thickness, the more wavelength conversion particles there are. Considering the friction between the wavelength conversion particles, even though it becomes increasingly difficult for the wavelength conversion particles to diffuse from the center to the surrounding areas, there is no significant difference in the number of wavelength conversion particles in the thickness direction at different locations. In other words, the wavelength conversion effect at different locations is similar, meaning that the light emitted from the front of the first wavelength conversion layer 130 is basically uniform and there is no obvious color difference.

[0045] Please combine Figure 1 Furthermore, the front surface of the first wavelength conversion layer 130 is curved. Due to the uniform transition of the curved surface, the number of wavelength conversion particles in the thickness direction at different positions is basically similar. That is, the number of wavelength conversion particles at the center position is basically equal to the number of wavelength conversion particles at the edge positions or other positions, thus achieving uniform light output from the front surface of the first wavelength conversion layer 130, with better uniformity and no color difference. In other embodiments, the front surface of the first wavelength conversion layer 130 can be formed by splicing multiple inclined surfaces.

[0046] Furthermore, the front surface of the first wavelength conversion layer 130 can be, but is not limited to, a sphere or an ellipsoid.

[0047] The side of the first wavelength conversion layer 130 is a convex curved surface with an opening that widens upwards. This part of the side can reflect light upwards at a large angle and emit light laterally, thereby improving light utilization.

[0048] The wavelength conversion particles in the first wavelength conversion layer 130 are fluorescent materials, specifically including at least one of yellow, red, and green fluorescent materials that emit yellow light and excite red and green light. In this embodiment, the first wavelength conversion layer 130 is a yellow phosphor layer, while the light-emitting chip 120 is a blue LED chip, whose emitted blue light is converted into white light by the yellow phosphor layer. Therefore, the yellow phosphor layer can output uniform white light, overcoming the problem of its edge position being bluish due to blue light leakage.

[0049] Furthermore, the wavelength conversion particles have a particle size of 10μm to 20μm. The smaller the particles, the easier they are to diffuse outwards, thus improving the situation where wavelength conversion particles tend to accumulate in the center. The particle size of the wavelength conversion particles can be, but is not limited to, 15μm.

[0050] The encapsulating adhesive layer 140 covers the side of the light-emitting chip 120, thus sealing the chip. Simultaneously, to cover the wire 150 extending from the side of the first wavelength conversion layer 130, the encapsulating adhesive layer 140 should cover at least a portion of the side of the first wavelength conversion layer 130, until the wire 150 is completely inside the encapsulating adhesive layer 140 and not exposed. However, the encapsulating adhesive layer 140 can only cover the side of the first wavelength conversion layer 130 (the outermost structure on the light-emitting chip 120), and cannot cover the front of the first wavelength conversion layer 130, to avoid affecting its light emission.

[0051] The encapsulating adhesive layer 140 is a reflective adhesive layer, capable of reflecting light emitted from the side, thus improving light utilization. In terms of material, the encapsulating adhesive layer 140 can be made of high-reflectivity white glue to achieve the reflective effect.

[0052] Please see Figure 2 , Figure 2 The diagram illustrates the molding process of the first wavelength conversion layer of the light-emitting device in this embodiment. First, an appropriate amount of wavelength conversion adhesive 131 (fluorescent adhesive) is applied to the front side of the light-emitting chip 120. Then, the wavelength conversion adhesive 131 is extruded using a mold 132 with a convex surface 133 to form the first wavelength conversion layer 130. The convex surface 133 is arc-shaped. Finally, after the wavelength conversion adhesive 131 has cured into the first wavelength conversion layer 130 (fluorescent adhesive layer), the mold 132 is removed. Clearly, the front side of the first wavelength conversion layer 130 is formed by the convex surface 133 of the mold 132, and its shape can change with the shape of the convex surface 133.

[0053] Please see Figure 3 , Figure 3 A cross-sectional view of the light-emitting device in the second embodiment of this application is shown. Based on the light-emitting device 100 in the first embodiment described above, the light-emitting device 100 in this embodiment further includes a second wavelength conversion layer 160, which covers the front side of the first wavelength conversion layer 130. Furthermore, the second wavelength conversion layer 160 is also a yellow phosphor layer, adjusting the color temperature of the light emitted from the first wavelength conversion layer 130 to improve the color area yield and thus improve the overall color area yield. In the thickness direction at the same location, the number of wavelength conversion particles in the second wavelength conversion layer 160 is less than the number of wavelength conversion particles in the first wavelength conversion layer 130. In other embodiments, the first wavelength conversion layer 130 may be a phosphor layer of another emitting color, and the second wavelength conversion layer 160 may also be a phosphor layer of a corresponding emitting color.

[0054] The front side of the second wavelength conversion layer 160 is planar, and this surface can also be molded.

[0055] The encapsulating adhesive layer 140 covers at least a portion of the sides of the second wavelength conversion layer 160, while covering the higher-level conductive wire 150. The highest point of the conductive wire 150 is higher than the first wavelength conversion layer 130 but lower than the second wavelength conversion layer 160. To completely cover the conductive wire 150 and prevent its exposure, the encapsulating adhesive layer 140 preferably completely covers all sides of the second wavelength conversion layer 160, but not the front side of the second wavelength conversion layer 160 (the outermost structure on the light-emitting chip 120), to avoid affecting its light emission.

[0056] The encapsulating adhesive layer 140 can be a thermally conductive adhesive layer, which contacts the side of the light-emitting chip 120 and can quickly conduct heat from the light-emitting chip 120, thereby improving the heat dissipation effect. The thermally conductive adhesive layer is a resin filled with heat-dissipating particles, and the resin is a white adhesive, which makes the encapsulating adhesive layer 140 white and also reflects light emitted from the side.

[0057] As for the other aspects of the light-emitting device 100 in this embodiment, they are basically the same as the other aspects of the light-emitting device 100 in the first embodiment above. The specific details can be referred to the description of the first embodiment above, and will not be repeated here.

[0058] Please see Figure 4 , Figure 4 A cross-sectional view of the light-emitting device in the third embodiment of this application is shown. Compared with the second wavelength conversion layer 160 of the light-emitting device 100 in the second embodiment, the front side of the second wavelength conversion layer 160 of the light-emitting device 100 in this embodiment is provided with a concave curved surface, and this surface is also formed by a mold 132 with a convex surface 133.

[0059] Furthermore, the front surface of the second wavelength conversion layer 160 is also curved, but the curvature of the front surface of the second wavelength conversion layer 160 is less than the curvature of the front surface (curved surface) of the first wavelength conversion layer 130.

[0060] As for the other aspects of the light-emitting device 100 in this embodiment, they are basically the same as the other aspects of the light-emitting device 100 in the second embodiment above. The specific details can be referred to the description of the second embodiment above, and will not be repeated here.

[0061] Please see Figure 5 , Figure 5A cross-sectional view of the light-emitting device in the fourth embodiment of this application is shown. Compared with the light-emitting device 100 in the first embodiment, the light-emitting chip 120 of the light-emitting device 100 in this embodiment is directly disposed on the substrate 170, and a lens 180 is added on the substrate 170. The lens 180 covers the light-emitting chip 120 and the first wavelength conversion layer 130.

[0062] The light-emitting device 100 specifically includes a substrate 170, a light-emitting chip 120, a first wavelength conversion layer 130, and a lens 180. The light-emitting chip 120 is disposed on the substrate 170. The first wavelength conversion layer 130 covers the front side of the light-emitting chip 120, and the edge thickness th1 of the first wavelength conversion layer 130 is greater than the center thickness th2, which is the maximum thickness. The lens 180 is sealed to the substrate 170, forming a cavity 190 between the lens and the substrate 170. Both the light-emitting chip 120 and the first wavelength conversion layer 130 are located in the cavity 190. The lens 180 not only seals the light-emitting chip 120 and the first wavelength conversion layer 130, but also processes the light emitted from the first wavelength conversion layer 130, thereby improving the light control capability of the light-emitting device 100.

[0063] The structure of substrate 170 is basically the same as that of substrate 112 in the above embodiment. The specific details can be found in the above description and will not be repeated here.

[0064] The front side of the first wavelength conversion layer 130 includes a central region 134 and a surrounding region 135. The central region 134 is planar, and the surrounding region 135 surrounds the central region 134 and gradually expands in the direction away from the light-emitting chip 120. Because the central region 134 is prone to particle accumulation, and the number of particles is basically similar, it is only necessary to set the surrounding region 135 to gradually expand in the light-emitting direction to ensure that the number of particles does not differ significantly at different positions. That is, the wavelength conversion effect at different positions is similar, and the light emitted from the front side of the first wavelength conversion layer 130 is basically uniform without significant color difference.

[0065] The shape of the central region 134 can be square or circular, while the shape of the surrounding region 135 is adapted to the shape of the central region 134. The area of ​​the central region 134 can be 5% or more of the front area of ​​the light-emitting chip 120.

[0066] Lens 180 is an integral structure, including a support portion 182 and an optical portion 184. One end of the support portion 182 is sealed on the substrate 170 and surrounds the light-emitting chip 120 and the first wavelength conversion layer 130. The optical portion 184 is located at the other end of the support portion 182. A space 186 exists between the optical portion 184 and the first wavelength conversion layer 130. This space 186 increases the optical interface inside the light-emitting device 100, further improving the light control capability of the light-emitting device 100. The optical portion 184 can be, but is not limited to, a convex lens, serving a light-focusing function. In other embodiments, lens 180 can be a separate structure, while the optical portion 184 can be a concave lens.

[0067] As for the other aspects of the light-emitting device 100 in this embodiment, they are basically the same as the other aspects of the light-emitting device 100 in the first embodiment above. The specific details can be referred to the description of the first embodiment above, and will not be repeated here.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A light emitting device, characterized by, include: The base (110) has a mounting groove (111); A light-emitting chip (120) is disposed in the mounting slot (111); A first wavelength conversion layer (130) covers the front side of the light-emitting chip (120). The edge thickness (th1) of the first wavelength conversion layer (130) is greater than the center thickness (th2), and is the maximum thickness. An encapsulating adhesive layer (140) is disposed in the mounting groove (111), surrounding the light-emitting chip (120) and the first wavelength conversion layer (130), and at least covering the side of the light-emitting chip (120).

2. The light-emitting device according to claim 1, characterized in that, The thickness of the first wavelength conversion layer (130) gradually increases from the center to the edge; or The front side of the first wavelength conversion layer (130) includes a central region (134) and a surrounding region (135). The central region (134) is planar, and the surrounding region (135) is arranged around the central region (134) and gradually expands in the direction away from the light-emitting chip (120).

3. The light emitting device of claim 2, wherein, The front of the first wavelength conversion layer (130) is curved, and the side of the first wavelength conversion layer (130) is convex.

4. The light emitting device of claim 1, wherein, Also includes: A second wavelength conversion layer (160) covers the front side of the first wavelength conversion layer (130).

5. The light-emitting device according to claim 4, characterized in that, The front side of the second wavelength conversion layer (160) is either planar or concave curved.

6. The light-emitting device according to claim 5, characterized in that, The front surface of the second wavelength conversion layer (160) is curved; The front surface of the first wavelength conversion layer (130) is curved, and the curvature of the front surface of the first wavelength conversion layer (130) is greater than the curvature of the front surface of the second wavelength conversion layer (160).

7. The light-emitting device according to any one of claims 1 to 6, characterized in that, Also includes: The wires (150) are respectively connected to the electrodes on the front side of the light-emitting chip (120) and the pads of the base (110); The encapsulating adhesive layer (140) covers the wire (150) but does not cover the front side of the outermost structure on the light-emitting chip (120).

8. The light-emitting device according to any one of claims 1 to 6, characterized in that, The encapsulating adhesive layer (140) is a reflective adhesive layer, or the encapsulating adhesive layer (140) is a thermally conductive adhesive layer.

9. A light-emitting device, characterized in that, include: substrate(170); A light-emitting chip (120) is disposed on the substrate (170); A first wavelength conversion layer (130) covers the front side of the light-emitting chip (120). The edge thickness (th1) of the first wavelength conversion layer (130) is greater than the center thickness (th2), and is the maximum thickness. Lens (180) is sealed to the substrate (170) and forms a cavity (190) between the lens (180) and the substrate (170). The light-emitting chip (120) and the first wavelength conversion layer (130) are both located in the cavity (190).

10. The light-emitting device according to claim 9, characterized in that, The thickness of the first wavelength conversion layer (130) gradually increases from the center to the edge; or The front side of the first wavelength conversion layer (130) includes a central region (134) and a surrounding region (135). The central region (134) is planar, and the surrounding region (135) is arranged around the central region (134) and gradually expands in the direction away from the light-emitting chip (120).

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