A combined backlight

Abstract

The present invention relates to a combined backlight, which includes a circuit board and a light source array disposed on the circuit board. It is characterized in that: the circuit board includes a first substrate and a second substrate. The first substrate has at least one main partition and at least one secondary partition. The secondary partition of the first substrate is a hollow window, and the second substrate is disposed within the hollow window. The second substrate is a double-sided circuit board. The second substrate and the first substrate are fixed and electrically connected through the connection of pin headers. The light source array includes a number of LED light sources, and the LED light sources are respectively disposed on the front surface of the main partition of the first substrate and the front surface of the second substrate. The advantages of the present invention are as follows: The backlight of the present invention not only satisfies the cost and heat dissipation advantages of the first substrate, has a wide industrial foundation and a large supply chain, but also has the advantage of a small space for the double-sided substrate. In addition, the heights of the LED light sources on the second substrate and the first substrate are the same, the optical OD as the backlight is consistent, and the light source control is simpler.

Description

Technical Field

[0001] The present invention relates to an LED backlight, and particularly to a backlight with good heat dissipation performance and small space. Background Art

[0002] Mini LED backlight adopts the direct - type LED backlight method. It reduces the size of traditional LED chips to between 100 microns and 200 microns, greatly increasing the number of backlight sources. Mini LED combined with Local Dimming technology can perform regional brightness adjustment, making black darker, white whiter, and colors more vivid, thus bringing a better visual experience.

[0003] Mini LED backlight has relatively high performance requirements for the PCB substrate. Currently, the PCB substrates mainly include single - sided PCB boards and double - sided PCB boards. Among them, the single - sided PCB board has good heat dissipation effect, low cost, and a wide industrial foundation, and has been widely used in display fields such as backlights. For the double - sided PCB substrate, although double - sided mounting can be achieved, in the soldering process, especially in the back - side reflow soldering process, it is easy to cause problems such as virtual soldering or detachment of LED devices, seriously affecting the reliability of device soldering. In addition, the poor heat dissipation performance of the double - sided PCB board is also a prominent problem restricting its application. Therefore, the double - sided PCB board also has obvious defects.

[0004] All in all, at present, domestic PCB substrates still cannot meet the performance requirements of the Mini backlight display field in terms of stability, reliability, etc. Since most of the current high - performance PCB substrates still rely on imports, the cost is relatively high. Now the market urgently needs PCB substrates with higher cost - effectiveness and better reliability, and the market prospect is very good. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a combined backlight with good heat dissipation performance, small space and consistent optical OD.

[0006] To solve the above technical problems, the technical solution of the present invention is: a combined backlight, including a circuit board and a light source array disposed on the circuit board. The innovation lies in that: the circuit board includes a first substrate, a second substrate and a connecting plate. The first substrate is a single-sided substrate, which has at least one main partition and at least one sub-partition. The sub-partition of the first substrate is a hollow window. The second substrate is a double-sided substrate, which is embedded in the hollow window of the first substrate, and makes the front surfaces of the first substrate and the second substrate flush. The second substrate is connected to the first substrate through the connecting plate to achieve fixation and electrical connection. Any one or more of a socket, electronic components or IC chips are installed on the back surface of the connecting plate; the light source array includes a number of LED light sources, and the LED light sources are respectively disposed on the front surface of the main partition of the first substrate and the front surface of the second substrate.

[0007] Preferably, the connecting plate is disposed on the back surfaces of the first and second substrates. The front surface of the connecting plate is welded to the second substrate for fixation and electrical connection. The two ends of the connecting plate are electrically connected and fixed to the first substrate by means of connectors, pin headers or welding.

[0008] Preferably, the second substrate is embedded in the hollow window of the first substrate and has a clearance fit. The coefficient of thermal expansion of the first substrate is denoted as α1, the coefficient of thermal expansion of the second substrate is denoted as α2, and the coefficient of thermal expansion of the connecting plate is denoted as α3, and α1 > α3 > α2.

[0009] Preferably, a graphene heat dissipation layer is additionally coated on the front and back surfaces of the connecting plate.

[0010] Preferably, the second substrate is an overall rectangular plate body. Outer arc chamfers are provided at the four corners of the rectangle, and arc-shaped notches recessed towards the center of the rectangle are provided in the middle of each side of the rectangle. And outer arc chamfers are also provided at the joints of the arc-shaped notches and the sides; the arc radius of the arc-shaped notches is 0.2 - 0.25 times the width of the second substrate; the outer arc chamfer radii at the four corners of the rectangle and the joints of the arc-shaped notches and the sides are the same, and are all 0.07 - 0.1 times the width of the second substrate.

[0011] The advantages of the present invention are as follows: The backlight of the present invention not only satisfies the cost and heat conduction advantages of the first substrate, has a wide industrial foundation and a large supply chain, but also has the advantages of a small space of the double-sided substrate. The scattered circuits on the circuit board are centralized and then dispersed, and the local high-density electronic components can be adjusted freely in terms of density, and the design freedom is higher. In addition, the height of the LED light sources on the second substrate and the first substrate is the same, the optical OD as the backlight is the same, and the light source control is simpler. And on the basis of a stable structure, a hollow window is provided on the first substrate, which can release stress during the working and heating process of the large-size single-sided substrate and reduce deformation.

[0012] Utilize the differences in the coefficients of thermal expansion of the first and second substrates and the connecting plate, and the additional cooperation of the graphene heat dissipation layer of the connecting plate to further reduce deformation and ensure the backlight uniformity when the backlight source operates in the temperature range of 40 to 60 °C. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic structural diagram of the combined backlight source in the present invention.

[0014] Figure 2 It is a schematic structural diagram of the second substrate in one embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The combined backlight source of the present invention includes a circuit board and a light source array disposed on the circuit board. Among them, as Figure 1 , shown in FIG. 2, the circuit board includes a first substrate 1, a second substrate 2, and a connecting plate 3.

[0016] The first substrate 1 is a single-sided substrate. The first substrate 1 has at least one main partition and at least one sub-partition. The sub-partition of the first substrate is a hollow window. The second substrate 2 is a double-sided substrate. The second substrate 2 is embedded in the hollow window of the first substrate 1, and the front surfaces of the first substrate 1 and the second substrate 2 are flush. The second substrate 2 is connected to the first substrate 1 through the connecting plate 3 to achieve fixation and electrical connection.

[0017] On the back surface of the connecting plate 3, any one or more of a socket, an electronic component 5, or an IC chip are installed; the array includes a plurality of LED light sources 4, and the LED light sources 4 are respectively disposed on the front surface of the main partition of the first substrate 1 and the front surface of the second substrate 2.

[0018] The connecting plate 3 is disposed on the back surfaces of the first substrate 1 and the second substrate 2. The front surface of the connecting plate 3 is welded to the second substrate 2 for fixation and electrical connection. Both ends of the connecting plate 3 are electrically connected and fixed to the first substrate 1 by means of a connector, a pin, or welding. The method of the connector, the pin, or welding is a well-known technology in the art and will not be elaborated here.

[0019] In order to ensure that when the backlight source operates in the temperature range of 40 to 60 °C, the deformation of the first and second substrates causes damage to the combined backlight source and uneven light emission, the second substrate 2 is embedded in the hollow window of the first substrate 1 and has a clearance fit with the first substrate 1. The coefficient of thermal expansion of the first substrate 1 is denoted as α1, the coefficient of thermal expansion of the second substrate 2 is denoted as α2, and the coefficient of thermal expansion of the connecting plate 3 is denoted as α3, which satisfies α1 > α3 > α2.

[0020] In addition, the front and back surfaces of the connecting plate 3 are additionally coated with a graphene heat dissipation layer to improve the heat dissipation effect and reduce the deformation of the working temperature of the connecting plate 3, which directly affects its connection with the first and second substrates.

[0021] To further optimize the internal stresses of the first and second substrates during the operation of the backlight, the second substrate 2 is an overall rectangular plate body. Outer arc chamfers are provided at the four corners of the rectangle, and arc-shaped notches 21 that are recessed towards the center of the rectangle are provided in the middle of each side of the rectangle. Outer circular arc chamfers are also provided at the joints between the arc-shaped notches 21 and the sides; the arc radius of the arc-shaped notch 21 is 0.2 to 0.25 times the width of the second substrate 2; the outer circular arc chamfers at the four corners of the rectangle and the joints between the arc-shaped notches 21 and the sides have the same arc radius, which is 0.07 to 0.1 times the width of the second substrate 2.

Claims

1. A combined backlight, comprising a circuit board and a light source array disposed on the circuit board, characterized in that: The circuit board includes a first substrate, a second substrate and a connecting plate. The first substrate is a single-sided substrate, which has at least one main partition and at least one sub-partition. The sub-partition of the first substrate is a hollow window. The second substrate is a double-sided substrate, which is embedded in the hollow window of the first substrate and makes the front surfaces of the first substrate and the second substrate flush. The second substrate is connected and fixed to the first substrate through the connecting plate to achieve electrical connection. Any one or more of a socket, electronic components or an IC chip is installed on the back surface of the connecting plate. The light source array includes a number of LED light sources, which are respectively arranged on the front surface of the main partition of the first substrate and the front surface of the second substrate. The connecting plate is arranged on the back surfaces of the first substrate and the second substrate. The front surface of the connecting plate is welded to the second substrate for fixing and electrical connection. Both ends of the connecting plate are electrically connected and fixed to the first substrate by means of connectors, pin headers or welding.

2. The combined backlight according to claim 1, wherein The second substrate is embedded in the hollow window of the first substrate and has a clearance fit with the first substrate. The coefficient of thermal expansion of the first substrate is denoted as α1, the coefficient of thermal expansion of the second substrate is denoted as α2, and the coefficient of thermal expansion of the connecting plate is denoted as α3, and α1>α3>α2.

3. The combined backlight according to claim 1 or 2, characterized in that: Graphene heat dissipation layers are additionally coated on the front and back surfaces of the connecting plate.

4. The combined backlight according to claim 1, wherein: The second substrate is a rectangular plate as a whole. Outer arc chamfers are provided at the four corners of the rectangle. Arc-shaped notches recessed towards the center of the rectangle are provided in the middle of each side of the rectangle, and outer arc chamfers are also provided at the connection of the arc-shaped notch and the side; the radius of the arc of the arc-shaped notch is 0.2-0.25 times the width of the second substrate; the radius of the outer arc chamfers at the four corners of the rectangle and the connection of the arc-shaped notch and the side are the same, both being 0.07-0.1 times the width of the second substrate.

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