Thermal Conductive Sheet for LED Backlight Heat Dissipation
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Solution Overview
Problem
LCDs using LEDs as backlight sources face issues with heat generation leading to reduced brightness, color shift, and increased weight and thickness due to the need for heat dissipation methods like radiating fins and cooling fans, which compromise light uniformity and efficiency.
Innovation Solution
Incorporating a thermal conductive sheet with higher surface-direction thermal conductivity than thickness-direction conductivity to efficiently dissipate heat from LEDs, eliminating the need for radiating fins and cooling fans by distributing heat across a larger surface area, thereby improving cooling efficiency and reducing the LCD's weight and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LEDs are used as light sources in the backlight unit, then brightness and color reproducibility are improved, but heat generation increases causing brightness reduction and color shift
Solution Approach 1:
The patent extracts the heat dissipation function from the optical path by placing the reflective plate with thermal conductive coating on the rear surface of the light guiding plate, away from the light transmission path. This allows heat to be conducted away from the LEDs without interfering with light output, resolving the contradiction between maintaining brightness and managing heat generation.
Solution Approach 2:
The reflective plate with thermal conductive coating acts as an intermediary between the LEDs and the heat sink. It conducts heat away from the LEDs while its reflective properties ensure that light is not blocked, mediating between the need for heat dissipation and the need to maintain illumination intensity.
2Temperature
If radiating fins and cooling fans are added to remove heat from LEDs, then heat dissipation is improved, but weight and thickness of the LCD increase
Solution Approach 1:
The patent removes the need for heavy radiating fins and cooling fans by extracting the heat dissipation function to a thin thermal conductive coating on the light guiding plate rear surface. This conducts heat away efficiently without adding significant weight, resolving the contradiction between heat dissipation capability and weight.
Solution Approach 2:
The thermal conductive coating on the reflective plate acts as a thin film that provides effective heat conduction without adding significant weight or thickness. This thin film approach replaces heavy traditional heat sinks, resolving the weight contradiction while maintaining heat dissipation effectiveness.
3Temperature
If radiating fins and cooling fans are added to remove heat from LEDs, then heat dissipation is improved, but thickness of the LCD increases
Solution Approach 1:
The patent extracts the heat dissipation function from the front optical path and implements it on the rear surface of the light guiding plate. This allows heat to be conducted away through the thickness direction without requiring additional space in the front-to-back dimension, resolving the contradiction between heat dissipation and thickness.
Solution Approach 2:
The patent changes the dimension of heat dissipation by conducting heat in the thickness direction through the light guiding plate to the rear surface, rather than requiring lateral expansion for radiating fins. This dimensional change allows effective heat dissipation without increasing overall thickness, resolving the contradiction between heat dissipation capability and LCD thickness.
4Temperature
If conventional heat dissipation methods are used, then heat removal is achieved, but light uniformity decreases
Solution Approach 1:
The patent extracts the heat dissipation function to the rear surface of the light guiding plate, separating it from the light transmission path. This ensures that heat removal does not interfere with light distribution and uniformity, resolving the contradiction between effective heat removal and maintaining light uniformity.
Solution Approach 2:
The reflective plate with thermal conductive coating serves as an intermediary that handles heat dissipation without interfering with light transmission. Its reflective properties ensure light is properly directed while its thermal conductive properties handle heat removal, mediating between these two functions to maintain both heat removal effectiveness and light uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances LED cooling efficiency, maintains light uniformity, and reduces the LCD's thickness and weight by effectively dissipating heat without the need for additional cooling components, while maintaining brightness and color accuracy.
Implementation Method 1
a thermal conductive sheet for receiving heat generated from the plurality of LEDs, wherein a thermal conductivity of the thermal conductive sheet in a surface direction is higher than a thermal conductivity in a thickness direction
Data Source
AI summary
According to an embodiment of the present invention, an LCD comprises a liquid crystal display panel, an LED circuit board disposed behind the liquid crystal display panel, wherein a plurality of LEDs are disposed on the LED circuit board, and a thermal conductive sheet for receiving heat generated from the plurality of LEDs, wherein a thermal conductivity of the thermal conductive sheet in a surface direction is higher than a thermal conductivity in a thickness direction.