Side light type LED backlight source

Abstract

The utility model discloses a sidelight type LED backlight source which comprises a light guide plate, a positioning frame arranged around the light guide plate is installed on the peripheral side of the light guide plate, an LED light bar facing the end face of the light guide plate and coupling light into the light guide plate is installed on the positioning frame, and a heat dissipation base frame is installed on the back side of the LED light bar. A cavity is formed in the heat dissipation base frame, a paraffin layer is arranged in the cavity, a space for expansion with heat and contraction with cold of the paraffin layer is reserved in the cavity, and a plurality of semiconductor chilling plates are attached to the back side of the heat dissipation base frame along the heat dissipation base frame; according to the utility model, the semiconductor chilling plate is used for cooling the heat dissipation base frame, so that active heat dissipation is carried out, a better heat dissipation effect is achieved, and the phenomenon that the local temperature is too high is avoided; the characteristic that the temperature change is small when the paraffin absorbs heat is used for absorbing heat, so that the temperature is prevented from rising too fast.

Description

Technical Field

[0001] This utility model relates to the technical field of LED backlights, specifically to a side-lit LED backlight. Background Technology

[0002] Edge-lit LED backlights install LED strips on the sides of the LCD panel (usually located at the top, bottom, or sides of the screen). The light is evenly diffused to the entire screen area through a light guide plate (PMMA or PC material). The light distribution is further optimized by optical films such as reflectors, diffuser films, and brightness enhancement films. Compared with direct-lit backlights, this reduces the space occupied by about 50%, making it suitable for ultra-thin TVs, tablets, and other devices. Compared with direct-lit layouts, the number of LEDs used is reduced by about 30-50%. However, because the spacing between LED beads is usually 2-3mm, such a dense layout can lead to excessive heat in some areas. Existing LED backlights mostly use finned tubes for natural heat dissipation, but the natural heat dissipation effect is poor and heat is prone to buildup. Therefore, it is necessary to design an edge-lit LED backlight that can actively dissipate heat. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a side-lit LED backlight.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] This utility model discloses a side-lit LED backlight, including a light guide plate. A positioning frame is installed around the light guide plate, and an LED strip facing the end face of the light guide plate and coupling light into the light guide plate is installed on the positioning frame. A heat dissipation base is installed on the back side of the LED strip. The heat dissipation base has a cavity inside, and a paraffin layer is provided in the cavity. Space is reserved in the cavity for thermal expansion and contraction of the paraffin layer. Multiple semiconductor cooling chips are attached along the back side of the heat dissipation base. A temperature sensor for detecting the temperature of the heat dissipation base is provided on one side of the heat dissipation base located on the LED strip. The system also includes a controller, and the temperature sensor and the semiconductor cooling chips are connected to the controller.

[0006] As a preferred technical solution of this utility model, a reflector is installed on the heat dissipation base to reflect the light emitted by the LED light strip onto the end face of the light guide plate.

[0007] As a preferred embodiment of this invention, the surface of the heat dissipation base is provided with a graphene thermal conductive layer.

[0008] As a preferred embodiment of this utility model, the positioning frame is provided with an installation port for installing the heat dissipation base frame on its periphery, and the heat dissipation base frame and the positioning frame are fixed together by positioning bolts.

[0009] As a preferred embodiment of this invention, a heat sink is installed between the heating surfaces of the plurality of semiconductor cooling chips, and the heat sink is provided with heat dissipation fins.

[0010] As a preferred embodiment of this utility model, the back side of the heat dissipation base is provided with an injection pipe communicating with the cavity, and the outer end of the injection pipe is threaded with a cap.

[0011] As a preferred embodiment of this utility model, the cavity is provided with a plurality of heat-conducting sheets inserted into the paraffin layer.

[0012] The beneficial effects of this utility model are:

[0013] This type of side-lit LED backlight features LED strips mounted on a positioning frame, facing the light guide plate and coupling light into it. The LED strips are mounted on a heat dissipation base, allowing heat generated during operation to be directly transferred to the base. The heat is absorbed by the paraffin layer within the base's cavity, preventing excessive temperature rise. This invention utilizes a thermoelectric cooler to cool the heat dissipation base, achieving active cooling and better heat dissipation while preventing localized overheating. A temperature sensor located on one side of the LED strip monitors the temperature of the heat dissipation base. When the temperature reaches a critical value, the controller activates the thermoelectric cooler to continue cooling until the temperature reaches a safe level, at which point the cooler stops operating, thus providing active cooling. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0015] Figure 1 This is a schematic diagram of the structure of a side-lit LED backlight according to this utility model;

[0016] Figure 2 This is a schematic diagram of the heat dissipation base of a side-lit LED backlight according to the present invention;

[0017] Figure 3 This is a schematic diagram showing the installation port of a side-lit LED backlight according to this utility model.

[0018] Figure 4 This is a schematic diagram of the heat dissipation base and positioning frame assembly structure of a side-lit LED backlight according to this utility model;

[0019] Figure 5This is a schematic diagram of the light-transmitting window of a side-lit LED backlight according to this utility model.

[0020] In the diagram: 1. Light guide plate; 2. Positioning frame; 3. LED light strip; 4. Heat dissipation base; 5. Cavity; 6. Paraffin layer; 7. Semiconductor cooling chip; 8. Temperature sensor; 9. Controller; 10. Reflector; 11. Graphene thermal conductive layer; 12. Mounting port; 13. Heat sink; 14. Heat dissipation fins; 15. Injection tube; 16. Cap; 17. Thermal conductive sheet; 18. Connecting block; 19. Connecting groove; 20. Pressure plate; 21. Light transmission window. Detailed Implementation

[0021] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0022] Example: Figure 1-5As shown, this utility model discloses a side-lit LED backlight, including a light guide plate 1. A positioning frame 2 is installed around the periphery of the light guide plate 1. An LED strip 3 facing the end face of the light guide plate 1 and coupling light into the light guide plate 1 is installed on the positioning frame 2. The edge of the light guide plate 1 is cut into a 45° bevel (tolerance ±0.5°), forming a total internal reflection interface with the LED light-emitting surface, guiding 80-85% of the light into the light guide plate. The bottom of the light guide plate also has optical films such as a reflector, a diffuser, and a brightness enhancement film to optimize the light distribution. These are not shown in the figure, but are features found in existing side-lit LED backlights. The positioning frame 2 has a light-transmitting window 21 corresponding to the end face of the light guide plate 1, which facilitates the entry of light emitted by the LED strip into the light guide plate 1. The positioning frame 2 also has pressure plates 20 that limit the two sides of the light guide plate 1 for positioning and fixing. These pressure plates 20 are not integrally formed with the positioning frame 2; they are fixed to the positioning frame 2 with bolts, facilitating the installation of the light guide plate. The detailed local structure is well-known to those skilled in the art and does not affect the heat dissipation implementation of the invention. Therefore, the specific structure will not be described in detail here. A heat dissipation base 4 is installed on the back side of the LED strip 3. The heat dissipation base 4 has a cavity 5 inside, and a paraffin wax layer 6 is provided inside the cavity 5. Space is reserved in the cavity 5 for the thermal expansion and contraction of the paraffin wax layer 6. When the paraffin wax melts, its volume expands by about 10-15%, and when it solidifies, its volume shrinks back to its original solid volume. This is because solid paraffin molecules are arranged in an ordered manner (density approximately 0.9 g / cm³). After melting, the increased thermal motion of the molecules leads to a larger spacing (liquid density approximately 0.78 g / cm³), leaving space for the thermal expansion and contraction of the paraffin layer 6, thus preventing serious damage to the heat dissipation base 4 caused by expansion and contraction. Multiple semiconductor cooling chips 7 are attached to the back side of the heat dissipation base 4. A temperature sensor 8 for detecting the temperature of the heat dissipation base 4 is located on one side of the LED light strip 3. The heat dissipation base also includes a controller. Both the temperature sensor 8 and the semiconductor cooling chips 7 are connected to the controller, which is not shown in the diagram. The controller can be mounted on the housing. The temperature sensor 8 and the semiconductor cooling chips 7 together form a simple feedback circuit, a technology familiar to those skilled in the art; therefore, the specific parameters will not be elaborated here.

[0023] This invention utilizes the characteristic of paraffin wax to absorb heat with minimal temperature change, thus preventing the temperature from rising too quickly.

[0024] In this invention, an LED strip 3 facing the end face of the light guide plate 1 and coupling light into the light guide plate 1 is installed on the positioning frame 2, thus forming a side-lit LED backlight. The LED strip 3 is mounted on the heat dissipation base 4, so the heat generated by the LED strip 3 during operation is directly transferred to the heat dissipation base 4. The heat is absorbed by the paraffin layer 6 in the cavity 5 of the heat dissipation base 4, which prevents the temperature from rising too quickly. The semiconductor cooling chip 7 is used to cool the heat dissipation base 4, thus achieving active heat dissipation and having a better heat dissipation effect, avoiding the occurrence of local overheating. A temperature sensor 8 is used to detect the temperature of the heat dissipation base 4 on one side of the LED strip 3. When the temperature reaches the heat dissipation value, the controller will control the semiconductor cooling chip 7 to work to cool down until the temperature drops to a safe value, at which point the semiconductor cooling chip 7 will stop working, thus achieving active heat dissipation.

[0025] The heat dissipation base 4 is equipped with a reflector 10 that reflects the light emitted by the LED light strip 3 onto the end face of the light guide plate 1. This light reflection ensures that more light enters the light guide plate, so that the brightness of the light guide plate can meet the usage requirements.

[0026] The surface of the heat dissipation base 4 is provided with a graphene thermal conductive layer. The graphene thermal conductive layer is not shown in the figure because it has a good thermal conductivity and can distribute heat evenly on the heat dissipation base 4. This ensures good heat dissipation uniformity during the heat dissipation process and avoids excessive local temperature.

[0027] The positioning frame 2 has an installation port 12 on its periphery for installing the heat dissipation base 4. The heat dissipation base 4 is fixed to the positioning frame 2 by positioning bolts. The heat dissipation base has docking blocks 18 at both ends, and docking grooves 19 that match the docking blocks 18 are provided on both sides of the installation port 12. After the docking blocks 18 and docking grooves 19 are docked, the light outlet of the reflector and the end face of the light guide plate face each other, and then they are fixed by positioning bolts, which facilitates installation and disassembly.

[0028] A heat sink 13 is installed between the heating surfaces of the plurality of semiconductor cooling chips 7. The heat sink 13 is provided with heat dissipation fins 14, which ensures that the heating surfaces of the semiconductor cooling chips have a good heat dissipation effect. In actual operation, heat dissipation through holes corresponding to the positions of the heat sink 13 should be provided on the casing to ensure a good airflow heat dissipation effect.

[0029] The heat dissipation base 4 has an injection pipe 15 connected to the cavity 5 on its back side. The outer end of the injection pipe 15 is threaded with a cap 16, which facilitates the injection of the paraffin layer into the cavity. During the preparation process, the heat dissipation base 4 is first recessed inward to form a cavity, and a heat-conducting plate is provided on the inner wall of the cavity. Then, a cover plate is welded onto the heat dissipation base 4 to cover the cavity, thus forming the cavity. Both the heat dissipation base and the cover plate are made of materials with good thermal conductivity.

[0030] The cavity 5 is provided with multiple heat-conducting plates 17 inserted into the paraffin layer 6, which gives the paraffin layer a better heat exchange area.

[0031] Working principle: This side-lit LED backlight has an LED strip 3 mounted on the positioning frame 2, facing the end face of the light guide plate 1 and coupling light into the light guide plate 1, thus forming a side-lit LED backlight. The LED strip 3 is mounted on the heat dissipation base 4, so the heat generated by the LED strip 3 during operation is directly transferred to the heat dissipation base 4. The heat is absorbed by the paraffin layer 6 in the cavity 5 of the heat dissipation base 4, which prevents the temperature from rising too quickly. The semiconductor cooling chip 7 is used to cool the heat dissipation base 4, thus achieving active heat dissipation and having a better heat dissipation effect, avoiding the occurrence of local overheating. A temperature sensor 8 is used to detect the temperature of the heat dissipation base 4 located on one side of the LED strip 3. When the temperature reaches the heat dissipation value, the controller will control the semiconductor cooling chip 7 to work to cool down until the temperature drops to a safe value, at which point the semiconductor cooling chip 7 will stop working, thus achieving active heat dissipation.

[0032] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A side light type LED backlight source, comprising a light guide plate (1), a positioning frame (2) is arranged around the light guide plate (1) and is mounted on the peripheral side of the light guide plate (1), and an LED light bar (3) is mounted on the positioning frame (2) and faces the end face of the light guide plate (1) and couples light into the light guide plate (1), characterized in that, A heat dissipation base (4) is installed on the back side of the LED light strip (3). The heat dissipation base (4) has a cavity (5) inside. A paraffin layer (6) is provided in the cavity (5). Space is reserved in the cavity (5) for thermal expansion and contraction of the paraffin layer (6). Multiple semiconductor cooling chips (7) are attached along the back side of the heat dissipation base (4). A temperature sensor (8) for detecting the temperature of the heat dissipation base (4) is provided on one side of the LED light strip (3). The heat dissipation base also includes a controller. The temperature sensor (8) and the semiconductor cooling chips (7) are both connected to the controller.

2. The edge-lit LED backlight of claim 1, wherein, The heat dissipation base (4) is equipped with a reflector (10) that reflects the light emitted by the LED light strip (3) to the end face of the light guide plate (1).

3. The edge-lit LED backlight of claim 1, wherein, The surface of the heat dissipation base (4) is provided with a graphene thermal conductive layer.

4. The edge-lit LED backlight of claim 1, wherein, The positioning frame (2) has an installation port (12) for installing the heat dissipation base frame (4) on its periphery. The heat dissipation base frame (4) and the positioning frame (2) are fixed together by positioning bolts.

5. The edge-lit LED backlight of claim 1, wherein, A heat sink (13) is installed between the heating surfaces of the plurality of semiconductor cooling chips (7), and the heat sink (13) is provided with heat dissipation fins (14).

6. The edge-lit LED backlight of claim 1, wherein, The heat dissipation base (4) is provided with an injection pipe (15) communicating with the cavity (5) on the back side, and a cap (16) is threaded onto the outer end of the injection pipe (15).

7. The edge-lit LED backlight of claim 5, wherein, The cavity (5) is provided with multiple heat-conducting plates (17) inserted into the paraffin layer (6).

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