Liquid crystal display device

Abstract

The application provides a liquid crystal display device, comprising a liquid crystal display panel, a backlight module, a flexible circuit board and a printed circuit board. The backlight module comprises a back plate and a light guide plate, and the light guide plate is arranged in a first accommodating space of the back plate. A first end of the flexible circuit board is electrically connected with a ground side part of the liquid crystal display panel, and a second end is electrically connected with a first end of the printed circuit board. A plurality of light emitting devices are arranged on a first surface of a second end of the printed circuit board, and a light emitting surface of the light emitting device is perpendicular to a plane where the printed circuit board is located. A side wall of the back plate is provided with a notch, and the light emitting device and part of the printed circuit board are accommodated in the first accommodating space of the back plate through the notch, and the light emitting surface of the light emitting device faces a light inlet surface of the light guide plate. The technical scheme of the application omits the traditional lamp strip assembly process and the lamp strip printed circuit board, cancels the groove reserved for the lamp strip wiring on the ground side of the back plate, and realizes further light and thin of the liquid crystal display device.

Description

Technical Field

[0001] This application relates to the field of display technology, and more specifically to a liquid crystal display device. Background Technology

[0002] Thinning and lightening are the current mainstream trends in LCD devices. In traditional ultra-thin LCD devices, light-emitting diodes (LEDs) provide backlight sources for the LCD panel. They are bonded to the printed circuit board of the LED strip by a bonding process. The printed circuit board and the LEDs together form the LED strip, which is attached to the side of the back panel of the LCD device's backlight module with thermally conductive adhesive, serving as a side-lit light source for the backlight module.

[0003] The aforementioned traditional technical solutions require a separate LED strip assembly process, increasing production complexity and cost. Furthermore, to accommodate the LED strip wiring, a dedicated slot needs to be reserved on the ground side of the back panel, preventing further reduction in the thickness of the LCD display device.

[0004] Therefore, it is necessary to propose a new technical solution to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a liquid crystal display device that aims to further reduce the thickness and weight of the liquid crystal display device.

[0006] An embodiment of this application provides a liquid crystal display device, which includes a liquid crystal display panel, a backlight module, a flexible circuit board, and a printed circuit board. The liquid crystal display panel is disposed on the backlight module. The backlight module includes a back plate and a light guide plate, and the light guide plate is disposed in a first receiving space of the back plate. A first end of the flexible circuit board is electrically connected to a portion of the liquid crystal display panel located on the ground side of the liquid crystal display device, and a second end of the flexible circuit board is electrically connected to a first end of the printed circuit board. A plurality of light-emitting devices are disposed on a first surface of the second end of the printed circuit board, and the light-emitting surfaces of the light-emitting devices are perpendicular to the plane on which the printed circuit board is located. A notch is provided on the sidewall of the back plate, and at least a portion of the light-emitting devices and the printed circuit board are received in the first receiving space of the back plate through the notch, with the light-emitting surfaces of the light-emitting devices facing the light-incident surfaces of the light guide plate.

[0007] In the aforementioned liquid crystal display device, the sidewall of the back panel is provided with at least one protruding wing, and the printed circuit board is fixed to the protruding wing.

[0008] In the aforementioned liquid crystal display device, a rivet post is provided on the extended wing, and the printed circuit board is fixed to the back plate by screws and the rivet post.

[0009] In the aforementioned liquid crystal display device, conductive adhesive is provided between the printed circuit board and the extended wing.

[0010] In the aforementioned liquid crystal display device, the extended wing includes a main body and a folded portion. The folded portion bends from one side of the main body of the extended wing to the space between the rear cover of the liquid crystal display device and the main body of the extended wing. A portion of the printed circuit board is disposed between the folded portion and the rear cover, and the conductive adhesive is disposed between the printed circuit board and the folded portion.

[0011] In the above-mentioned liquid crystal display device, a heat-conducting component is provided on the second surface of the second end of the printed circuit board at a position corresponding to the light-emitting device. The heat-conducting component is attached to the back cover of the liquid crystal display device and is used to conduct the heat of the light-emitting device to the back cover.

[0012] In the aforementioned liquid crystal display device, a protrusion is provided in the back cover of the liquid crystal display device at a position corresponding to the light-emitting device. A heat-conducting layer is provided on the protrusion, and the printed circuit board is disposed on the heat-conducting layer. The heat-conducting layer is used to conduct the heat of the light-emitting device to the back cover through the protrusion.

[0013] In the above-mentioned liquid crystal display device, a plurality of conductive pads are provided on the first surface of the second end of the printed circuit board, the light-emitting device is electrically connected to the conductive pads, and the printed circuit board is used to control the light-emitting device to emit light.

[0014] In the aforementioned liquid crystal display device, the liquid crystal display device further includes a front frame, an outer frame, and a rear cover; the flexible circuit board and the printed circuit board are housed in a second receiving space located on the ground side of the liquid crystal display device, which is enclosed by the front frame, the outer frame, and the rear cover.

[0015] In the aforementioned liquid crystal display device, a portion of the outer frame is disposed between the front frame and the rear cover to support the front frame and the rear cover.

[0016] This application directly mounts the light-emitting device onto the printed circuit board of the liquid crystal display device, making the light-emitting surface of the device perpendicular to the plane of the printed circuit board. The light-emitting device and part of the printed circuit board are housed in the first receiving space of the back panel through a notch in the side wall, allowing the light-emitting surface of the device to directly face the light-incident surface of the light guide plate. This eliminates the need for a separate LED strip printed circuit board in traditional solutions, simplifying the assembly process and reducing material costs. Since the light-emitting device is directly integrated onto the printed circuit board of the liquid crystal display device, only the fixed printed circuit board needs to be completed during assembly to achieve precise alignment between the light-emitting device and the light guide plate, improving assembly efficiency and accuracy.

[0017] Furthermore, this application uses extended wings on the sidewalls of the back panel to secure the printed circuit board, such as using rivet screws or conductive adhesive, which allows the printed circuit board to be firmly mounted on the back panel, enhancing the stability of the structure.

[0018] In addition, by setting heat-conducting components on the second surface of the printed circuit board, or by setting protrusions at corresponding positions on the back cover and cooperating with heat-conducting layers, this application effectively conducts the heat generated by the light-emitting device to the back cover, preventing the light-emitting device from overheating and causing performance degradation or shortened lifespan. These heat dissipation components also serve to support the printed circuit board, ensuring that the light-emitting device is facing the light-incident surface of the light guide plate, thereby improving the utilization efficiency of the light source.

[0019] Furthermore, the liquid crystal display device of this application fully utilizes the internal space of the liquid crystal display device by housing the flexible circuit board and the printed circuit board in a second accommodating space enclosed by the front frame, outer frame, and rear cover, making the overall structure more compact. Since the printed circuit board is horizontally mounted and fixed, the traces of the light-emitting devices occupy the horizontal space, eliminating the need for additional LED strip trace slots on the ground side of the back panel, thereby reducing the thickness of the liquid crystal display device.

[0020] In summary, by eliminating the slot reserved for LED strip routing on the ground side of the backplate, this application makes the thickness of the liquid crystal display device only the sum of the thickness from the front of the liquid crystal display panel to the back of the backlight module, the gap between the backplate and the back cover, and the thickness of the back cover. Compared with the traditional solution, this reduces the height of the LED strip routing slot, thus achieving further thinning of the liquid crystal display device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a display device provided in an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the first embodiment of the display device provided in this application.

[0023] Figure 3 This is a schematic diagram of a second embodiment of the display device provided in this application.

[0024] Figure 4 This is a schematic diagram of a third embodiment of the display device provided in this application.

[0025] Figure 5 This is a schematic diagram of the fourth embodiment of the display device provided in this application.

[0026] Figure 6 This is a schematic diagram of the back panel in the first to fourth embodiments of the display device provided in this application. Detailed Implementation

[0027] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0028] The terms “first,” “second,” and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different technical features. The terms “multiple,” and similar words mean two or more, unless otherwise expressly specified.

[0029] The embodiments of this application can be combined with each other.

[0030] like Figure 1 As shown, the liquid crystal display device provided in the embodiments of this application includes a liquid crystal display panel, a timing controller TCON, a source driver circuit DD, and a power management chip (not shown in the figure; the power management chip can be integrated with the timing controller TCON into the same chip). The liquid crystal display panel includes a display area and a non-display area. The display area is provided with an array of m×n pixels PX, where m and n are integers greater than 1. The non-display area is located around the display area and is used to arrange driving circuits and various signal lines. The liquid crystal display panel also includes multiple gate lines (GL1~GLn), multiple data lines (DL1~DLm), and a gate driver circuit GOA. The multiple gate lines (GL1~GLn) extend along a first direction and are arranged along a second direction, and the multiple data lines (DL1~DLm) extend along the second direction and are arranged along the first direction, with the first direction perpendicular to the second direction. The gate driver circuit GOA is disposed in the non-display area and is electrically connected to the multiple gate lines (GL1~GLn). The source driver circuit DD is electrically connected to the multiple data lines (DL1~DLm) through a flexible circuit board. The timing controller TCON is electrically connected to the gate drive circuit GOA and the source drive circuit DD, respectively.

[0031] A liquid crystal display panel includes a thin-film transistor array substrate, an opposing substrate, and a liquid crystal layer disposed between the two substrates. The thin-film transistor array substrate includes a glass substrate, a first metal layer disposed on the glass substrate, a gate insulating layer disposed on the first metal layer, a semiconductor layer disposed on the gate insulating layer, a second metal layer disposed on the semiconductor layer, a passivation layer disposed on the second metal layer, and pixel electrodes disposed on the passivation layer. The first metal layer includes gate lines (GL1-GLn), gate electrodes, etc. The second metal layer includes data lines (DL1-DLm), source electrodes, drain electrodes, etc. The opposing substrate includes a glass substrate, a black matrix disposed on the glass substrate, a color filter layer disposed on the black matrix, and a common electrode disposed on the color filter layer.

[0032] Each pixel (PX) includes at least one thin-film transistor (TFT) and a pixel electrode. The gate of the TFT is electrically connected to the corresponding gate line, the source is electrically connected to the corresponding data line, and the drain is electrically connected to the corresponding pixel electrode. When the gate line outputs a high-level scan signal, the TFT is turned on, and the data signal on the data line is transmitted to the pixel electrode through the TFT; when the gate line outputs a low-level scan signal, the TFT is turned off, and the pixel electrode maintains the voltage corresponding to the data signal.

[0033] The gate drive circuit GOA includes n cascaded gate drive sub-circuits, each electrically connected to a gate line. Under the control of the timing controller TCON, the gate drive sub-circuits sequentially output scan signals, scanning each row of pixels PX in the display area line by line. The source drive circuit DD, under the control of the timing controller TCON, generates and outputs data signals based on the image data. The timing controller TCON receives and processes externally input image data and timing signals, generates control signals, and transmits the image data to the source drive circuit DD. The power management chip provides operating voltages to various parts of the liquid crystal display device, including a common voltage for the common electrode of the liquid crystal display panel, a gate drive voltage for the gate drive circuit GOA, and a gamma voltage for the source drive circuit DD.

[0034] In order to further reduce the thickness and weight of liquid crystal display devices, embodiments of this application provide a liquid crystal display device.

[0035] In the embodiments of this application, such as Figures 2 to 6 As shown, the liquid crystal display device includes a liquid crystal display panel 101, a backlight module 102, a front frame 104, an outer frame 105, a rear cover 103, a flexible circuit board 106, and a printed circuit board 107. The liquid crystal display panel 101 is disposed on the backlight module 102. The backlight module 102 includes a back plate 1021 and a light guide plate 1022. The light guide plate 1022 is disposed in a first receiving space 115 of the back plate 1021. The first receiving space 115 is surrounded by the bottom plate and sidewalls of the back plate 1021 and is a semi-enclosed space. A first end of the flexible circuit board 106 is electrically connected to a portion of the liquid crystal display panel 101 located on the ground side of the liquid crystal display device, and a second end of the flexible circuit board 106 is electrically connected to a first end of the printed circuit board 107. A portion of the outer frame 105 is disposed between the front frame 104 and the rear cover 103 to support the front frame 104 and the rear cover 103.

[0036] In the embodiments of this application, a plurality of light-emitting devices 109 are disposed on the first surface of the second end of the printed circuit board 107, and the light-emitting surface of the light-emitting devices 109 is perpendicular to the plane on which the printed circuit board 107 is located. These light-emitting devices 109 are horizontally emitting LED beads, which are bonded to the first surface of the second end of the printed circuit board 107 of the liquid crystal display device by means of bonding, serving as the light source of the backlight module 102. A plurality of conductive pads are also disposed on the first surface of the second end of the printed circuit board 107, and the light-emitting devices 109 are electrically connected to the conductive pads. The printed circuit board 107 is used to control the light-emitting devices 109 to emit light.

[0037] The backlight module 102 has a notch 10211 on the sidewall of its backplate 1021. The size A of the notch 10211 is large enough to accommodate the printed circuit board 107 of the liquid crystal display device (size less than or equal to A). At least a portion of the light-emitting device 109 and the printed circuit board 107 are housed in the first receiving space 115 of the backplate 1021 through the notch 10211, with the light-emitting surface of the light-emitting device 109 facing the light-incident surface of the light guide plate 1022. The sidewall of the backplate 1021 has a plurality of protruding wings 10212 located on one side of the backplate 1021. These protruding wings 10212 are located above the notch 10211 (on the side of the notch 10211 away from the base plate) and are used to fix the printed circuit board 107 of the liquid crystal display device and also to provide an electrical grounding connection.

[0038] The back panel 1021 has a notch 10211 on its sidewall to accommodate the printed circuit board 107 and the light-emitting device 109. However, this notch 10211 structure reduces the overall strength of the back panel 1021, especially in the area near the notch 10211. When the liquid crystal display device is subjected to external force or vibration, stress concentration is likely to occur in the area near the notch 10211, causing the back panel 1021 to deform or crack.

[0039] In embodiments of this application, reinforcing ribs are provided at the edges of the notch 10211 of the back plate 1021. The reinforcing ribs are arranged along the periphery of the notch 10211, forming a closed-loop structure to enhance the rigidity of the area surrounding the notch 10211. The height of the reinforcing ribs is the same as the height of the sidewall of the back plate 1021. The cross-sectional shape of the reinforcing ribs is T-shaped or L-shaped to increase structural strength. T-shaped reinforcing ribs include a base perpendicular to the sidewall of the back plate 1021 and a top parallel to the sidewall of the back plate 1021; L-shaped reinforcing ribs include a vertical portion perpendicular to the sidewall of the back plate 1021 and a horizontal portion parallel to the sidewall of the back plate 1021, with the height of the vertical portion being 70% to 90% of the total height of the reinforcing rib. Furthermore, rounded corners are provided at the connection between the bottom plate of the back plate 1021 and the sidewall. The rounded corners are used to reduce stress concentration and improve the overall strength and deformation resistance of the back plate 1021. This technical solution ensures that even when the back plate 1021 has a notch 10211, the back plate 1021 still has sufficient strength and rigidity to maintain structural stability in various usage environments.

[0040] In the embodiments of this application, the flexible circuit board 106 is folded, and the flexible circuit board 106 and the printed circuit board 107 are housed in a second receiving space 116 located on the ground side of the liquid crystal display device, which is enclosed by the front frame 104, the outer frame 105, and the rear cover 103. The second end of the printed circuit board 107 faces the side of the light guide plate 1022, and the light-emitting device 109 and the light guide plate 1022 of the backlight module 102, which are disposed on the printed circuit board 107 connected to the flexible circuit board 106, are positioned opposite each other.

[0041] In the embodiments of this application, the printed circuit board 107 can be fixed in a variety of ways:

[0042] like Figure 2 As shown, in the first fixing method, a rivet 110 is provided on the protruding wing 10212, and the printed circuit board 107 is fixed to the back plate 1021 by screws 111 and rivets 110. The screws 111 and rivets 110 are fixed together. The combination of screws 111 and rivets 110 provides high-strength mechanical fixing, capable of withstanding vibration and impact, ensuring the stability of the printed circuit board 107. Simultaneously, the metal screws 111 and rivets 110 also provide an electrical grounding path.

[0043] like Figure 3As shown, in the second fixing method, the protruding wing 10212 includes a main body 102121 and a folded portion 102122. The folded portion 102122 bends from one side of the main body 102121 of the protruding wing 10212 to the space between the rear cover 103 of the liquid crystal display device and the main body 102121 of the protruding wing 10212. A portion of the printed circuit board 107 is disposed between the folded portion 102122 and the rear cover 103. Conductive adhesive 112 is disposed between the printed circuit board 107 and the protruding wing 10212. The conductive adhesive 112 has an adhesive function, which can firmly bond the printed circuit board 107 to the folded portion 102122. At the same time, due to the conductive properties of the conductive adhesive 112, the printed circuit board 107 is fixed and grounded through the conductive adhesive 112 and the folded portion 102122 of the back plate 1021. The conductive adhesive 112 is disposed between the printed circuit board 107 and the folded portion 102122. This fixing method not only achieves mechanical fixation between the printed circuit board 107 and the folded portion 102122 of the backplate 1021, but also achieves electrical grounding through conductive adhesive 112, reducing assembly complexity.

[0044] In the embodiments of this application, the light-emitting device 109 (LED lamp bead) generates a large amount of heat when it is working. When the light-emitting device 109 is directly attached to the printed circuit board 107, if the heat dissipation is poor, the temperature of the light-emitting device 109 will be too high, which will not only reduce the luminous efficiency, but also shorten the service life, and may even damage the light-emitting device 109.

[0045] To address the aforementioned technical problems, in the embodiments of this application, the light-emitting device 109 can have various heat conduction solutions:

[0046] like Figure 4 As shown, in the first heat conduction scheme, a heat-conducting component 113 is provided on the second surface of the second end of the printed circuit board 107 at a position corresponding to the light-emitting device 109. The heat-conducting component 113 is attached to the back cover 103 of the liquid crystal display device to form a heat conduction channel. The heat-conducting component 113 is used to conduct the heat of the light-emitting device 109 to the back cover 103, and then dissipate it to the external environment through the back cover 103. The heat-conducting component 113 can be made of a material with high thermal conductivity, such as aluminum, copper or other metal materials, or it can be a flexible heat-conducting material such as thermally conductive silicone. The heat-conducting component 113 also supports the printed circuit board 107 so that the light-emitting device 109 disposed on the printed circuit board 107 faces the light-incident surface of the light guide plate 1022.

[0047] like Figure 5As shown, in the second heat conduction scheme, a protrusion 1031 is provided in the back cover 103 of the liquid crystal display device at a position corresponding to the light-emitting device 109. A heat-conducting layer 114 is provided on the protrusion 1031, and the printed circuit board 107 is disposed on the heat-conducting layer 114. The heat-conducting layer 114 is used to conduct the heat of the light-emitting device 109 to the back cover 103 through the protrusion 1031. The heat-conducting layer 114 is one of thermally conductive adhesive, thermally conductive silicone, or thermally conductive grease. The protrusion 1031 is also used to support the printed circuit board 107 so that the light-emitting device 109 disposed on the printed circuit board 107 faces the light-incident surface of the light guide plate 1022.

[0048] In the embodiments of this application, since a horizontally emitting light-emitting device 109 is selected as the light source of the backlight module 102, and the light-emitting device 109 is bonded to the printed circuit board 107 of the liquid crystal display device by a bonding method, the traditional printed circuit board of the light strip is eliminated. During assembly, only the fixed printed circuit board 107 of the liquid crystal display device needs to be completed to complete the alignment of the light-emitting device 109 and the light guide plate 1022 (the light-emitting device 109 naturally aligns with the light incident surface of the light guide plate 1022), simplifying the assembly process. Only the fixed printed circuit board 107 needs to be completed to simultaneously complete the alignment of the light-emitting device 109 and the light guide plate 1022, greatly improving assembly efficiency and accuracy. The conductive lines on the printed circuit board 107 are used to realize the electrical signal transmission and power supply of the light-emitting device 109.

[0049] In the embodiments of this application, since the printed circuit board 107 of the liquid crystal display device is horizontally mounted and fixed, the traces of the light-emitting device 109 occupy the horizontal space, eliminating the need to additionally provide slots for the light strip traces on the ground side of the backplate 1021. Figures 2 to 5 As shown, the thickness of the liquid crystal display device is equal to the thickness (H1) from the front of the liquid crystal display panel 101 to the back of the backlight module 102, plus the gap (H2) between the back of the backlight module 102 and the back cover 103, plus the thickness (H3) of the back cover 103. In contrast, the thickness of a conventional liquid crystal display device is equal to the thickness (H1) from the front of the liquid crystal display panel 101 to the back of the backplate 1021 of the backlight module 102, plus the gap (H2) between the backplate 1021 and the back cover 103, plus the thickness (H3) of the back cover 103, plus the height (H4) of the slot for the LED strip routing on the ground side of the backplate 1021. The printed circuit board 107 is horizontally mounted and fixed, allowing the light-emitting device 109 routing lines to occupy horizontal space, eliminating the need for additional LED strip routing slots on the ground side of the backplate 1021, further optimizing space utilization and reducing the thickness of the liquid crystal display device. Therefore, the liquid crystal display device provided in this embodiment is thinner than a conventional liquid crystal display device.

[0050] In practical applications, when the liquid crystal display device is subjected to external force or vibration, the light-emitting device 109 on the printed circuit board 107 may be slightly offset from the light-incident surface of the light guide plate 1022, causing the light to not be able to fully enter the light guide plate 1022, reducing the light utilization rate, and thus affecting the display brightness and uniformity.

[0051] In the embodiments of this application, the protruding wing 10212 provided on the sidewall of the back plate 1021 may be further provided with at least two positioning protrusions. These positioning protrusions are located at different edges of the printed circuit board 107 and are used to restrict the movement of the printed circuit board 107 in the plane. The number of positioning protrusions is two to four, preferably three, to form a three-point positioning structure. The height of the positioning protrusions matches the thickness of the printed circuit board 107, so that the printed circuit board 107 can be accurately embedded in the space between the positioning protrusions. At the same time, positioning holes or positioning grooves are provided on the printed circuit board 107 at positions corresponding to the positioning protrusions. The diameter of the positioning hole is 0.05 mm to 0.2 mm larger than the diameter of the positioning protrusion, the width of the positioning groove is 0.05 mm to 0.2 mm larger than the width of the positioning protrusion, and the length is 1.5 to 3 times the diameter of the positioning protrusion, so that the positioning protrusions can be inserted into these positioning holes or positioning grooves, further improving the positioning accuracy. The edges of the positioning holes or positioning grooves are chamfered or rounded to facilitate the insertion of the positioning protrusions. This technical solution ensures that even when subjected to external force or vibration, the light-emitting device 109 and the light-incident surface of the light guide plate 1022 can maintain precise alignment, improve light utilization, and guarantee display brightness and uniformity.

[0052] During the use of a liquid crystal display device, due to the different coefficients of thermal expansion of the printed circuit board 107 and the backplate 1021, temperature changes can cause thermal stress between them. After long-term use, the accumulation of this thermal stress may lead to fatigue failure at the connection point between the printed circuit board 107 and the backplate 1021, affecting the stability of the mounting and the reliability of the electrical connection.

[0053] In the embodiments of this application, an elastic buffer layer is provided between the printed circuit board 107 and the protruding wing 10212. This elastic buffer layer is made of a conductive material with a certain degree of elasticity, such as conductive silicone or conductive rubber. The shape of the elastic buffer layer matches the contact area between the printed circuit board 107 and the protruding wing 10212, and can be rectangular, circular, or other shapes. The area of ​​the elastic buffer layer covers the entire contact area between the printed circuit board 107 and the protruding wing 10212, or multiple independent elastic buffer blocks can be provided in the contact area. The thickness of the elastic buffer layer is 0.1 mm to 0.5 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. The hardness of the elastic buffer layer is Shore A hardness of 30 to 70, for example, Shore A hardness of 30, 40, 50, 60, or 70. The surface of the elastic buffer layer can be designed as a smooth surface or a surface with micro-protrusions, the height of which is 0.05 mm to 0.2 mm, and the density of which is 5 to 20 per square centimeter, to increase the contact area and contact stability. The elastic buffer layer absorbs stress caused by the difference in thermal expansion coefficients between the printed circuit board 107 and the backplane 1021, preventing fatigue failure of the connection point. On the other hand, due to its conductivity, it still ensures the electrical connection between the printed circuit board 107 and the backplane 1021. The volume resistivity of the elastic buffer layer is from 0.1 ohm·cm to 10 ohm·cm, for example, it can be 0.1 ohm·cm, 1 ohm·cm, 5 ohm·cm, or 10 ohm·cm. Furthermore, an arc-shaped transition region is designed around the fixing point of the printed circuit board 107. The radius of the arc-shaped transition region is from 1 mm to 3 mm, and the angle of the arc-shaped transition region is from 90 degrees to 180 degrees to reduce stress concentration and further improve the reliability and service life of the connection.

[0054] When a liquid crystal display device operates for extended periods, especially at high brightness settings, the heat generated by the light-emitting device 109 can concentrate in localized areas of the printed circuit board 107, causing excessively high temperatures in those areas. This not only affects the performance and lifespan of the light-emitting device 109 but may also cause deformation of the printed circuit board 107, impacting the overall structural stability.

[0055] In an embodiment of this application, a heat diffusion layer is disposed on the second surface of the printed circuit board 107. This heat diffusion layer covers the area on the printed circuit board 107 corresponding to the light-emitting device 109 and its surrounding area, and is made of a material with high thermal conductivity, such as graphite sheet, aluminum foil, or copper foil. The thickness of the heat diffusion layer is 0.05 mm to 0.3 mm, for example, it can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, or 0.3 mm. The shape of the heat diffusion layer can be rectangular, circular, or other shapes. The area of ​​the heat diffusion layer is larger than the projected area of ​​the light-emitting device 109, for example, 1.5 to 3 times the projected area of ​​the light-emitting device 109. The heat diffusion layer is used to rapidly diffuse the heat generated by the light-emitting device 109 to a larger area, avoiding heat concentration in local areas and reducing local temperature peaks. The thermal conductivity of the heat diffusion layer ranges from 100 W / m·Kelvin to 400 W / m·Kelvin. For example, the thermal conductivity of graphite sheets can reach 300 W / m·Kelvin to 400 W / m·Kelvin, aluminum foil has a thermal conductivity of approximately 200 W / m·Kelvin, and copper foil has a thermal conductivity of approximately 380 W / m·Kelvin. Simultaneously, thermal grease is filled between the heat diffusion layer and the heat-conducting component 113. The thickness of the thermal grease is 0.1 mm to 0.5 mm, and the thermal conductivity of the thermal grease ranges from 1.5 W / m·Kelvin to 5 W / m·Kelvin, for example, it can be 1.5 W / m·Kelvin, 2 W / m·Kelvin, 3 W / m·Kelvin, 4 W / m·Kelvin, or 5 W / m·Kelvin. The thermal grease fills the tiny gaps between the heat diffusion layer and the heat-conducting component 113, improving heat conduction efficiency and further enhancing heat dissipation performance.

[0056] This application directly mounts the light-emitting device 109 onto the printed circuit board 107 of the liquid crystal display device, making the light-emitting surface of the light-emitting device 109 perpendicular to the plane of the printed circuit board 107. The light-emitting device 109 and part of the printed circuit board 107 are housed in the first receiving space 115 of the back plate 1021 through a notch 10211 in the side wall of the back plate 1021. This allows the light-emitting surface of the light-emitting device 109 to directly face the light-incident surface of the light guide plate 1022, eliminating the need for a separate LED strip printed circuit board in traditional solutions, thus simplifying the assembly process and reducing material costs. Since the light-emitting device 109 is directly integrated onto the printed circuit board 107 of the liquid crystal display device, only the fixing of the printed circuit board 107 is required during assembly to achieve precise alignment between the light-emitting device 109 and the light guide plate 1022, improving assembly efficiency and accuracy.

[0057] Furthermore, this application uses extended wings 10212 provided on the side wall of the back plate 1021 to fix the printed circuit board 107, such as fixing with rivets 110, screws 111 or conductive adhesive 112, so that the printed circuit board 107 can be stably mounted on the back plate 1021, thereby enhancing the stability of the structure.

[0058] Furthermore, by providing a heat-conducting component 113 on the second surface of the printed circuit board 107, or by providing a protrusion 1031 at a corresponding position on the back cover 103 in conjunction with a heat-conducting layer 114, this application effectively conducts the heat generated by the light-emitting device 109 to the back cover 103, preventing the light-emitting device 109 from overheating and causing performance degradation or shortened lifespan. These heat dissipation components also serve to support the printed circuit board 107, ensuring that the light-emitting device 109 is directly facing the light-incident surface of the light guide plate 1022, thereby improving the utilization efficiency of the light source.

[0059] Furthermore, the liquid crystal display device of this application fully utilizes the internal space of the liquid crystal display device by housing the flexible circuit board 106 and the printed circuit board 107 in the second receiving space 116 formed by the front frame 104, the outer frame 105, and the rear cover 103, making the overall structure more compact. Since the printed circuit board 107 is horizontally mounted and fixed, the traces of the light-emitting device 109 occupy the horizontal space, eliminating the need to provide additional lamp strip trace slots on the ground side of the back plate 1021, thereby reducing the thickness of the liquid crystal display device.

[0060] In summary, by eliminating the slot reserved for LED strip routing on the ground side of the backplate 1021, this application makes the thickness of the liquid crystal display device only the sum of the thickness from the front of the liquid crystal display panel 101 to the back of the backplate 1021 of the backlight module 102, the gap between the backplate 1021 and the back cover 103, and the thickness of the back cover 103. Compared with the traditional solution, this reduces the height of the LED strip routing slot and achieves further thinning of the liquid crystal display device.

[0061] The embodiments of this application have been described in detail above. The content of this specification should not be construed as limiting the scope of protection of this application.

Claims

1. A liquid crystal display device, characterized in that, The liquid crystal display device includes a liquid crystal display panel, a backlight module, a flexible circuit board, a printed circuit board, a front frame, an outer frame, and a rear cover, wherein the liquid crystal display panel is disposed on the backlight module; The backlight module includes a back plate and a light guide plate, wherein the light guide plate is disposed in the first accommodating space of the back plate; The first end of the flexible circuit board is electrically connected to a portion of the liquid crystal display panel located on the ground side of the liquid crystal display device, and the second end of the flexible circuit board is electrically connected to the first end of the printed circuit board. A plurality of light-emitting devices are disposed on the first surface of the second end of the printed circuit board, and the light-emitting surface of the light-emitting devices is perpendicular to the plane on which the printed circuit board is located. The back panel has a notch in its sidewall. At least a portion of the light-emitting device and the printed circuit board are housed in the first receiving space of the back panel through the notch. The light-emitting surface of the light-emitting device faces the light-incident surface of the light guide plate. The sidewall of the back panel has at least one protruding wing. The printed circuit board is fixed to the protruding wing. Conductive adhesive is disposed between the printed circuit board and the protruding wing. The protruding wing includes a main body and a folded portion. The folded portion bends from one side of the main body of the protruding wing to the space between the rear cover of the liquid crystal display device and the main body of the protruding wing. A portion of the printed circuit board is disposed between the folded portion and the rear cover. The conductive adhesive is disposed between the printed circuit board and the folded portion. The flexible circuit board is folded over, and the flexible circuit board and the printed circuit board are housed in a second receiving space located on the ground side of the liquid crystal display device, which is surrounded by the front frame, the outer frame and the rear cover; A portion of the outer frame is disposed between the front frame and the rear cover to support the front frame and the rear cover; The notch edge of the back plate is provided with a reinforcing rib, which is arranged along the periphery of the notch to form a closed loop. The height of the reinforcing rib is the same as the height of the side wall of the back plate, and the cross-sectional shape of the reinforcing rib is T-shaped or L-shaped.

2. The liquid crystal display device according to claim 1, characterized in that, A heat-conducting component is provided on the second surface of the second end of the printed circuit board at a position corresponding to the light-emitting device. The heat-conducting component is attached to the back cover of the liquid crystal display device and is used to conduct the heat of the light-emitting device to the back cover.

3. The liquid crystal display device according to claim 1, characterized in that, A protrusion is provided in the back cover of the liquid crystal display device at a position corresponding to the light-emitting device. A heat-conducting layer is provided on the protrusion, and the printed circuit board is disposed on the heat-conducting layer. The heat-conducting layer is used to conduct the heat of the light-emitting device to the back cover through the protrusion.

4. The liquid crystal display device according to claim 1, characterized in that, A plurality of conductive pads are provided on the first surface of the second end of the printed circuit board, the light-emitting device is electrically connected to the conductive pads, and the printed circuit board is used to control the light-emitting device to emit light.

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