A light emitting device

Abstract

The application provides a light-emitting device, which comprises a circuit substrate, an LED light source arranged on the circuit substrate, and a lens arranged on the circuit substrate and covering the LED light source, wherein the lens is connected with a soldering sheet, and the lens is attached to the circuit substrate in a reflow soldering mode through the soldering sheet. The lens is connected with the soldering sheet, so that the lens can be attached to the circuit substrate in a reflow soldering mode through the soldering sheet, the connection stability of the lens on the circuit substrate is ensured, the loosening between the lens and the circuit substrate caused by temperature change or vibration is reduced, the structural stability and optical performance of the light-emitting device are improved, the failure rate of the light-emitting device caused by connection problems is reduced, and the service life of the light-emitting device is prolonged.

Description

Technical Field

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

[0002] In the field of television backlighting, the light-emitting device generally includes a circuit board, an LED light source, and a lens. The LED light source is typically mounted on the circuit board, and the lens covers the LED light source, bonded to the circuit board using thermosetting adhesive or UV adhesive. However, in practical applications, the light-emitting device may face different environmental conditions, such as temperature changes and vibrations, leading to weak adhesion of the thermosetting and UV adhesives. This can cause the lens to loosen from the circuit board, thus affecting the optical performance and overall stability of the light-emitting device. Utility Model Content

[0003] The purpose of this application is to provide a light-emitting device to solve the technical problem of weak connection between the lens and the circuit board in the prior art.

[0004] To achieve the above objectives, the technical solution adopted in this application is: to provide a light-emitting device, including a circuit board, an LED light source disposed on the circuit board, and a lens disposed on the circuit board and covering the LED light source, wherein the lens is connected to a solder pad, and the lens is mounted on the circuit board by reflow soldering through the solder pad.

[0005] In some embodiments, the welding piece is fixed to the lens by bonding, riveting, or secondary injection molding.

[0006] In some embodiments, the welding tab is at least partially embedded in the lens.

[0007] In some embodiments, the circuit board has a first pad and a second pad, the LED light source has a third pad, the LED light source is mounted to the first pad via the third pad, and the solder pad is mounted to the second pad.

[0008] In some embodiments, the lens is made of silicone or epoxy resin.

[0009] In some embodiments, the number of welding tabs is multiple, and each welding tab surrounds the LED light source.

[0010] In some embodiments, a plurality of the solder pads are arranged in a circle around the central axis of the lens, and the cross-section of the first optical portion of the lens, which is at least used to attach to the circuit board, is polygonal, with the plurality of solder pads corresponding to a plurality of corners of the first optical portion.

[0011] In some embodiments, the welding piece has a plurality of first side surfaces connected end to end, and the connecting line between two adjacent first side surfaces is a first ridge; the first optical part has a plurality of second side surfaces connected end to end, and the connecting line between two adjacent second side surfaces is a second ridge; a welding piece is provided for each second ridge, and the connecting surface between the second ridge and the corresponding first ridge passes through the central axis of the lens.

[0012] In some embodiments, the lens has an optical cavity recessed on the side facing the circuit board, the inner surface of the optical cavity is a light incident surface, the cross-sectional area of ​​the light incident surface gradually decreases from the bottom opening to the top, and the LED light source is housed in the optical cavity.

[0013] In some embodiments, the lens has a conical groove recessed on the side opposite to the circuit board, and the center line of the conical groove coincides with the center line of the optical cavity.

[0014] The beneficial effects of the light-emitting device provided in this application are as follows: The lens is connected to a solder pad, and the lens is mounted on the circuit board via the solder pad using reflow soldering. Reflow soldering offers the advantage of stable soldering, ensuring the connection stability of the lens on the circuit board. This reduces the possibility of loosening between the lens and the circuit board due to temperature changes or vibrations, thereby improving the structural stability and optical performance of the light-emitting device, reducing the failure rate caused by connection problems, and extending the service life of the light-emitting device. Simultaneously, the solder pad provides a reliable soldering connection point between the lens and the circuit board, enabling a firm connection between the lens, which was originally difficult to solder directly, and the circuit board. Furthermore, the solder pad and circuit board are connected via reflow soldering. During the solder paste melting process, the relative positions of the solder pad and the pad on the circuit board are automatically corrected, ensuring the lens is in the correct position, greatly improving the optical performance and quality stability of the light-emitting device. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the light-emitting device provided in the embodiments of this application;

[0017] Figure 2 This is a schematic diagram of the circuit board and LED light source in the light-emitting device provided in the embodiments of this application;

[0018] Figure 3 A side view of the lens and welding sheet in the light-emitting device provided in the embodiments of this application;

[0019] Figure 4 A top view of the lens and welding sheet in the light-emitting device provided in the embodiments of this application;

[0020] Figure 5 A side view of the lens and welding sheet in a light-emitting device provided in another embodiment of this application;

[0021] Figure 6 This is a top view of the lens and welding sheet in a light-emitting device provided in another embodiment of this application.

[0022] The following are the labeling elements in the figure:

[0023] 100, Lens; 110, First optical section; 120, Second optical section; 130, First mounting surface; 131, Second side surface; 132, Second ridge; 140, Optical cavity; 141, Light incident surface; 150, Third optical section; 160, Tapered groove; 161, Diffuser surface; 200, LED light source; 210, Third mounting surface; 300, Solder pad; 310, Second mounting surface; 320, First side surface; 330, First ridge; 400, Circuit board; 410, First solder pad; 420, Second solder pad. Detailed Implementation

[0024] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0025] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0026] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0027] Furthermore, the terms "first" and "second" are used 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 as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] Please see Figures 1 to 4 The light-emitting device provided in the embodiments of this application will now be described.

[0029] The light-emitting device includes a circuit board 400, an LED light source 200 disposed on the circuit board 400, and a lens 100 disposed on the circuit board 400 and covering the LED light source 200. The lens 100 is connected to a solder pad 300, and the lens 100 is mounted on the circuit board 400 by reflow soldering through the solder pad 300.

[0030] The device typically includes multiple LED light sources 200 and lenses 100. Each LED light source 200 is regularly distributed on the circuit board 400 and electrically connected to it. Each lens 100 is correspondingly positioned over each LED light source 200. The LED light sources 200 emit light under the control of the circuit board 400, and the lenses 100 perform optical processing on the light emitted by the LED light sources 200 to ensure that the light emitted by the light-emitting device meets the requirements.

[0031] Solder pads 300 are typically made of metals such as copper and nickel. These metals have good electrical and thermal conductivity and can form a good solder joint with the solder paste during the reflow soldering process.

[0032] Specifically, when mounting the lens 100 onto the circuit board 400, solder paste is first applied to the corresponding pads on the circuit board 400; then, the lens 100 is transported to a position directly above the circuit board 400 using a mounting device, and the solder pads 300 are placed on the corresponding solder paste; next, the circuit board 400 and the lens 100 are transported together to a reflow soldering device for heating to melt the solder paste, allowing it to flow and align the positions of the solder pads 300 accordingly; finally, cooling is performed to ensure that the lens 100 is firmly mounted on the circuit board 400.

[0033] In the light-emitting device of this embodiment, the lens 100 is connected to a solder pad 300, and the lens 100 is mounted on the circuit board 400 via the solder pad 300 using reflow soldering. Reflow soldering offers the advantage of stable soldering, ensuring the connection stability of the lens 100 on the circuit board 400. This reduces the possibility of loosening between the lens 100 and the circuit board 400 due to temperature changes or vibrations, thereby improving the structural stability and optical performance of the light-emitting device, reducing the failure rate caused by connection problems, and extending the service life of the light-emitting device. Simultaneously, the solder pad 300 provides a reliable soldering connection point between the lens 100 and the circuit board 400, enabling the lens 100, which would otherwise be difficult to solder directly, to achieve a firm connection with the circuit board 400 via the solder pad 300. Meanwhile, the solder pad 300 and the circuit board 400 are connected by reflow soldering. During the melting process of the solder paste, the relative positions of the solder pads on the solder pad 300 and the circuit board 400 are automatically corrected, so that the lens 100 is in the correct position, which greatly improves the optical performance and quality stability of the light-emitting device, thereby reducing after-sales costs and waste of raw materials caused by light-emitting device failure or non-compliance.

[0034] In some embodiments, the LED light source 200 generally includes a mounting frame, at least one LED chip mounted in the mounting frame, and an encapsulating adhesive layer filling the space between the at least one LED chip and the mounting frame. The number of LED chips can be one or more; when there are multiple LED chips, each LED chip is used to emit light of a different color.

[0035] In some embodiments, the lens 100 is made of silicone material. Silicone can withstand high temperatures of around 260°C and has good high-temperature resistance, meeting the heat resistance requirements of the reflow soldering process. Compared with existing PMMA (polymethyl methacrylate) lenses 100, silicone not only adapts to high-temperature soldering environments but also possesses better flexibility and elasticity, which can, to some extent, buffer the stress generated at the connection between the lens 100 and the circuit board 400 due to temperature changes or vibrations, thus improving the overall structural stability. Furthermore, the silicone lens 100 still retains advantages such as high transparency and low haze. It is understood that in other embodiments of this application, the lens 100 may also be made of other materials capable of withstanding the high temperatures of reflow soldering and possessing high transparency and low haze characteristics, such as epoxy resin, PC (polycarbonate), or optical-grade plastic composites; this is not a limiting factor.

[0036] In some embodiments, the welding piece 300 is fixed to the lens 100 by adhesive bonding to ensure a secure connection between the welding piece 300 and the lens 100, preventing it from falling off during subsequent processing and use. Understandably, in other embodiments of this application, the welding piece 300 can also be securely fixed to the lens 100 by riveting. Furthermore, the welding piece 300 can also be fixed to the lens 100 by secondary injection molding; specifically, the lens 100 can be formed using the welding piece 300 as a base through secondary injection molding, thereby connecting the welding piece 300 and the lens 100 as a single unit.

[0037] In some embodiments, the solder pad 300 is at least partially embedded in the lens 100. For example, a portion of the solder pad 300 may be embedded in the lens 100, while another portion of the solder pad 300 extends beyond the lens 100 for mounting onto the circuit board 400. Alternatively, the solder pad 300 may be completely embedded in the lens 100, with the surface of the solder pad 300 intended for mounting onto the circuit board 400 exposed outside the lens 100. In this embodiment, by at least partially embedding the solder pad 300 in the lens 100, the connection reliability between the solder pad 300 and the lens 100 can be improved, preventing the solder pad 300 from detaching during subsequent processing and use.

[0038] In some embodiments, please refer to Figure 3 The lens 100 has a first mounting surface 130 for attaching to the circuit board 400, and the solder pad 300 has a second mounting surface 310 for attaching to the circuit board 400. The solder pad 300 is embedded in the lens 100, with its second mounting surface 310 exposed above the lens 100, and flush with the first mounting surface 130 of the lens 100. Furthermore, the solder pad 300 is also fixed to the lens 100 by adhesive bonding. This configuration not only allows the lens 100 and the solder pad 300 to be flatly attached to the circuit board 400, but also ensures a secure connection between the solder pad 300 and the lens 100, preventing the solder pad 300 from detaching during subsequent processing and use.

[0039] In some embodiments, please refer to Figure 1 and Figure 2The circuit board 400 has a first pad 410 and a second pad 420, and the LED light source 200 has a third pad (not shown). The LED light source 200 is mounted to the first pad 410 via the third pad, and the solder pad 300 is mounted to the second pad 420. This arrangement allows both the LED light source 200 and the lens 100 to be mounted on the circuit board 400 via reflow soldering. Specifically, in actual operation, a first pad 410 with the same size and shape as the third pad can be set on the circuit board 400 at the position corresponding to the LED light source 200, and a second pad 420 with matching size and shape can be set on the circuit board 400 at the position corresponding to the solder pad 300. Next, the first pad 410 and the second pad 420 are surface-treated, and solder paste is applied to the first pad 410 and the second pad 420 to ensure good wetting between the first pad 410 and the second pad 420 and the corresponding solder paste, thus ensuring soldering quality. Next, using a high-precision pick-and-place machine, the lens 100 with the solder pad 300 attached and the LED light source 200 are placed together on the corresponding positions of the circuit board 400. After placement, the reflow soldering process begins. The circuit board 400 with the lens 100 and LED light source 200 attached is placed in the reflow soldering equipment. A suitable reflow soldering temperature profile is set based on the characteristics of the solder paste and the temperature range that the lens 100, circuit board 400, and LED light source 200 can withstand. During the reflow soldering process, when the temperature rises to the melting point of the solder paste, the solder paste begins to melt. At this time, due to the surface tension and other physical properties of the solder paste, the positional deviation between the solder pad 300 and the second pad 420 on the circuit board 400 is automatically corrected. Specifically, in its liquid state, the solder paste exerts a pulling force on the solder pad 300, causing it to move towards the optimal connection position with the second pad 420. After cooling and solidification, the solder pad 300 and the second pad 420 form a strong solder connection, allowing the lens 100 to be precisely fixed on the circuit board 400, and maintaining a precise relative position between the circuit board 400 and the LED light source 200. This application mounts both the LED light source 200 and the solder pad 300 onto the circuit board 400, enabling simultaneous mounting of the lens 100 and the LED light source 200, and completing the soldering fixation in one step through reflow soldering. Reflow soldering, as a highly automated and mature process, offers high production speed, significantly shortening the production cycle of a single light-emitting device and substantially improving overall production efficiency, meeting market demands for large-scale production. Furthermore, increased production efficiency means producing more light-emitting devices per unit time, reducing the production cost per unit of light-emitting device.

[0040] In some embodiments, please refer to Figure 2 and Figure 3The lens 100 has a first mounting surface 130 for mounting on the circuit board 400, the solder pad 300 has a second mounting surface 310 for mounting on the circuit board 400, and the LED light source 200 has a third mounting surface 210 for mounting on the circuit board 400. The first mounting surface 130, the second mounting surface 310, and the third mounting surface 210 are flush. In this embodiment, by aligning the first mounting surface 130, the second mounting surface 310, and the third mounting surface 210, the mounting stability of the LED light source 200 and the lens 100 on the circuit board 400 can be ensured. It is understood that in other embodiments of this application, the second mounting surface 310 and the third mounting surface 210 may also be flush and protrude outward relative to the first mounting surface 130; this is not a unique limitation.

[0041] In some embodiments, please refer to Figures 1 to 4 There are multiple welding tabs 300, each surrounding the LED light source 200. In this embodiment, the arrangement of multiple welding tabs 300 ensures the reliable and stable mounting of the lens 100 on the circuit board 400, thereby ensuring the uniformity of optical processing of the LED light source 200 by the lens 100, and further improving the circumferential uniformity of the light emitted from the lens 100.

[0042] In some embodiments, please refer to Figure 1 The central axis of the LED light source 200 coincides with the central axis of the lens 100. Here, the central axis of the lens 100 refers to the central axis of the lens 100 perpendicular to the first mounting surface 130. When the cross-section of the lens 100 is circular, the central axis of the lens 100 is a line passing through the center of each cross-section; when the cross-section of the lens 100 is square, the central axis of the lens 100 is a line passing through the intersection of the diagonals of each cross-section. Similarly, the central axis of the LED light source 200 is also perpendicular to the central axis of the first mounting surface 130. In this embodiment, by setting the central axis of the LED light source 200 and the central axis of the lens 100 to coincide, the optical processing effect of the lens 100 on the LED light source 200 is uniformly distributed circumferentially, thereby making the light emission effect of the light-emitting device uniform circumferentially. It is understood that in other embodiments of this application, the central axis of the LED light source 200 may be set to deviate from the central axis of the lens 100; this is not a unique limitation.

[0043] In some embodiments, please refer to Figures 1 to 4Multiple solder pads 300 are arranged in a circle around the central axis of the lens 100. The first optical part 110 of the lens 100, which is at least used to attach to the circuit board 400, has a polygonal cross-section, and the multiple solder pads 300 are correspondingly disposed at multiple corners of the first optical part 110. The above arrangement ensures that when the lens 100 is polygonal, the positions of each solder pad 300 are evenly distributed, and that each corner of the lens 100 is evenly attached to the circuit board 400.

[0044] For some specific embodiments, please refer to Figure 4 The first optical section 110 has a square cross-section, and four welding tabs 300 are arranged in a circle around the central axis of the lens 100, with each of the four welding tabs corresponding to one of the four corners of the first optical section 110. This arrangement ensures that, when the lens 100 is square, the positions of the welding tabs 300 are evenly distributed, and that the four corners of the lens 100 are uniformly mounted on the circuit board 400. It is understood that in other embodiments of this application, the cross-section of the first optical section 110 of the lens 100 can also be designed as a pentagon, hexagon, or a polygon with more than one hexagonal shape, or it can be designed as a circle. In this case, the number of welding tabs 300 can be two, three, four, or more, and each welding tab 300 can be arranged in a circle. It should be noted that the cross-section of the first optical section 110 refers to the surface of the first optical section 110 perpendicular to the central axis of the lens 100.

[0045] In some embodiments, please refer to Figure 4 The welding piece 300 is square, corresponding to the first mounting surface 130 of the square. The square welding piece 300 has better welding stability.

[0046] In some embodiments, please refer to Figure 4 The welding piece 300 has multiple first side surfaces 320 connected end to end, and the connecting line between two adjacent first side surfaces 320 is a first ridge line 330; the first optical part 110 has multiple second side surfaces 131 connected end to end, and the connecting line between two adjacent second side surfaces 131 is a second ridge line 132; a welding piece 300 is provided for each second ridge line 132, and the connecting surface between the second ridge line 132 and the corresponding first ridge line 330 passes through the central axis of the lens 100. The above arrangement can ensure that each welding piece 300 can firmly and stably mount the lens 100 onto the circuit board 400.

[0047] Preferably, the welding piece 300 has four first side surfaces 320 connected end to end; the first optical part 110 of the lens 100 has four second side surfaces 131 connected end to end.

[0048] In addition, the shape and size of the solder pad 300 need to be customized according to the design of the first mounting surface 130 of the lens 100 and the second solder pad 420 on the circuit board 400.

[0049] In some embodiments, please refer to Figure 3 and Figure 4 The lens 100 includes a first optical section 110 and a second optical section 120. The first optical section 110 and the second optical section 120 are stacked along the central axis of the lens 100. The cross-section of the first optical section 110 is square, and the cross-section of the second optical section 120 is circular, with the outer radial direction gradually decreasing to a preset value away from the first optical section 110. Each welding piece 300 is embedded in the first optical section 110, and the first mounting surface 130 is the surface of the first optical section 110 facing away from the second optical section 120. In this embodiment, by designing the second optical section 120 of the lens 100 as circular, the circular shape has the characteristic of isotropy, which allows light to diffuse in all directions at a relatively uniform angle, thereby expanding the illumination range and reducing blind spots. The first optical section 110 is designed as square, which can better focus the light, concentrate the light on a specific area, and improve the illuminance of that area. Furthermore, the close fit of the square first optical section 110 can guide more light to the second optical section 120 for scattering, improving the luminous efficiency of the entire light-emitting device. Understandably, in other embodiments of this application, the cross-section of the first optical section 110 may also be circular, and the cross-section of the second optical section 120 may also be square.

[0050] In some embodiments, please refer to Figure 1 and Figure 3 An optical cavity 140 is recessed on the side of the lens 100 facing the circuit board 400. The optical cavity 140 passes through the first optical section 110 and extends to the second optical section 120. The LED light source 200 is housed in the optical cavity 140, and the inner surface of the optical cavity 140 is the light incident surface 141. The design of the optical cavity 140 not only reduces the volume of the entire light-emitting device by housing the LED light source 200 in the optical cavity 140, but also increases the area of ​​the light incident surface 141 on the inner surface of the optical cavity 140, causing the light emitted by the LED light source 200 to undergo diffuse reflection at the light incident surface 141, thereby making the light more uniform.

[0051] In some embodiments, the cross-sectional area of ​​the light incident surface 141 gradually decreases from the bottom opening to the top, and the LED light source 200 is located at the center of the light incident surface 141. This arrangement results in a larger refraction angle of the light incident surface 141, allowing a single beam of light to be diffusely reflected into multiple beams, thus making the light more uniform.

[0052] Preferably, the light incident surface 141 is semi-elliptical or conical.

[0053] In some embodiments, a tapered groove 160 is recessed on the side of the lens 100 away from the circuit board 400. The center line of the tapered groove 160 coincides with the center line of the optical cavity 140. The tapered groove 160 is used to increase the emission angle of the lens 100. The diameter of the tapered groove 160 gradually increases from the inside of the lens 100 to the outside. The inner surface of the tapered groove 160 is set as a diffusion surface 161. Through the design of the tapered groove 160, the light in the middle of the diffusion surface 161 can be reflected to the edge of the diffusion surface 161, thereby expanding the emission angle so that the overall light emission effect of the lens 100 is more uniform.

[0054] In other embodiments of this application, please refer to Figure 5 and Figure 6 The lens 100 also includes a third optical section 150, which is disposed on the side of the second optical section 120 opposite to the first optical section 110. The third optical section 150 and the second optical section 120 are coaxially arranged, and the outer diameter of the third optical section 150 is smaller than the outer diameter of the second optical section 120. The outer diameter of the second optical section 120 gradually decreases from the first optical section 110 to the third optical section 150. The third optical section 150 is cylindrical, and a tapered groove 160 is recessed on the side of the third optical section 150 opposite to the second optical section 120. The center line of the tapered groove 160 coincides with the center line of the optical cavity 140.

[0055] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A light-emitting device, characterized in that, The device includes a circuit board, an LED light source disposed on the circuit board, and a lens disposed on the circuit board and covering the LED light source. The lens is connected to a solder pad, and the lens is mounted on the circuit board by reflow soldering through the solder pad.

2. The light-emitting device as described in claim 1, characterized in that, The welding piece is fixed to the lens by bonding, riveting, or secondary injection molding.

3. The light-emitting device as described in claim 1, characterized in that, The welding piece is at least partially embedded in the lens.

4. The light-emitting device as described in claim 1, characterized in that, The circuit board has a first pad and a second pad, the LED light source has a third pad, the LED light source is mounted to the first pad through the third pad, and the solder pad is mounted to the second pad.

5. The light-emitting device as claimed in claim 1, characterized in that, The lens is made of silicone or epoxy resin.

6. The light-emitting device according to any one of claims 1 to 5, characterized in that, The number of welding pieces is multiple, and each welding piece surrounds the LED light source.

7. The light-emitting device as described in claim 6, characterized in that, The plurality of welding tabs are arranged in a circle around the central axis of the lens. The cross-section of the first optical part of the lens, which is at least used to attach to the circuit board, is polygonal. The plurality of welding tabs are respectively disposed at the corners of the first optical part.

8. The light-emitting device as claimed in claim 7, characterized in that, The welding piece has multiple first side surfaces connected end to end, and the connecting line between two adjacent first side surfaces is a first ridge line; the first optical part has multiple second side surfaces connected end to end, and the connecting line between two adjacent second side surfaces is a second ridge line; a welding piece is provided for each second ridge line, and the connecting surface between the second ridge line and the corresponding first ridge line passes through the central axis of the lens.

9. The light-emitting device according to any one of claims 1 to 5, characterized in that, The lens has an optical cavity recessed on the side facing the circuit board. The inner surface of the optical cavity is the light incident surface. The cross-sectional area of ​​the light incident surface gradually decreases from the bottom opening to the top. The LED light source is housed in the optical cavity.

10. The light-emitting device as claimed in claim 9, characterized in that, The lens has a conical groove recessed on the side away from the circuit board, and the center line of the conical groove coincides with the center line of the optical cavity.

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