Backlight Unit Thermal Management via Variable Heat Resistance
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Solution Overview
Problem
Liquid crystal display devices experience non-uniform temperature distribution due to heat emitted by light sources, leading to irregular color density and brightness, as well as varying life spans of light emitting diodes, causing image distortion and reduced LED lifespan.
Innovation Solution
The implementation of temperature adjusting members with varying heat resistance and thickness, strategically placed between circuit boards and a frame, to evenly distribute heat and maintain uniform temperature across the device, using materials like polystyrene resin or polyurethane resin with different heat transfer coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light sources (LEDs) are arranged at a rear portion of the liquid crystal panel to irradiate light onto the entire surface, then illumination coverage is improved, but non-uniform temperature distribution occurs causing irregular color density and brightness
Solution Approach 1:
The patent applies local quality by providing temperature adjusting members at specific locations where temperature adjustment is needed. The temperature adjusting members are positioned between the circuit board and frame at locations corresponding to areas requiring temperature control, allowing different parts of the device to have different thermal characteristics tailored to their specific needs.
Solution Approach 2:
The temperature adjusting members act as intermediary elements between the light sources and the frame. These members mediate heat transfer by having different heat resistance values, controlling how heat from the LEDs is transmitted to the frame and surrounding structures, thereby achieving uniform temperature distribution.
2Loss of energy
If heat emitting members are provided to discharge heat to the rear portion, then heat dissipation is improved, but temperature difference between center and sides increases due to convection current
Solution Approach 1:
The patent applies local quality by providing temperature adjusting members at specific locations where temperature adjustment is needed. The temperature adjusting members are positioned between the circuit board and frame at locations corresponding to areas requiring temperature control, allowing different parts of the device to have different thermal characteristics tailored to their specific needs.
Solution Approach 2:
The patent applies parameter changes by varying the heat resistance values of the temperature adjusting members based on their positions. Members at different locations have different heat resistance parameters, with those near the center having different values compared to those at the sides, thereby compensating for convection current effects and achieving uniform temperature distribution.
3Loss of energy
If temperature difference in the inside of the LCD device is excessive, then heat dissipation is improved, but life span of LEDs varies with dead LEDs existing together with active LEDs
Solution Approach 1:
The patent applies local quality by providing temperature adjusting members at specific locations where temperature adjustment is needed. The temperature adjusting members are positioned between the circuit board and frame at locations corresponding to areas requiring temperature control, allowing different parts of the device to have different thermal characteristics tailored to their specific needs.
Solution Approach 2:
The patent applies equipotentiality by creating uniform temperature conditions across all LED locations. Through the strategic placement of temperature adjusting members with appropriate heat resistance values, the patent equalizes the thermal environment for all LEDs, ensuring they operate under similar temperature conditions and achieve comparable life spans.
4Speed
If temperature in inner upper portion is higher than inner lower portion, then natural convection is improved, but optical power of light sources changes excessively affecting image quality
Solution Approach 1:
The patent applies local quality by providing temperature adjusting members at specific locations where temperature adjustment is needed. The temperature adjusting members are positioned between the circuit board and frame at locations corresponding to areas requiring temperature control, allowing different parts of the device to have different thermal characteristics tailored to their specific needs.
Solution Approach 2:
The patent applies parameter changes by varying the heat resistance values of the temperature adjusting members based on their positions. Members at different locations have different heat resistance parameters, with those near the center having different values compared to those at the sides, thereby compensating for convection current effects and achieving uniform temperature distribution.
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
This solution achieves uniform temperature distribution, minimizing brightness and color density irregularities and extending the life span of light emitting diodes by ensuring all LEDs operate under similar conditions.
Implementation Method 1
temperature adjusting members which have different heat resistance and are provided between the circuit boards and the frame
Implementation Method 2
temperature adjusting members attached to rear portions of the circuit boards so as to transfer heat emitted from the light emitting diodes
Implementation Method 3
a temperature in a center portion of the LCD device is remarkably higher than a temperature in both sides of the LCD device due to a convection current phenomenon
Data Source
AI summary
A backlight unit and a liquid crystal display device are provided. The backlight unit includes light emitting diodes; and a plurality of temperature adjusting members which reduce a temperature difference formed by emission of heat of the backlight unit, the heat being caused by a convection current of air in a vicinity of the light emitting diodes and by heat emitted from the plurality of light emitting diodes. The liquid crystal display device includes a plurality of circuit boards which are provided with light emitting diodes; a frame on which the circuit boards are installed; and a plurality of temperature adjusting members provided between the plurality of circuit boards and the frame, wherein the plurality of temperature adjusting members having different heat resistances are arranged according to a temperature distribution of heat emitted from the light emitting diodes such that a uniform temperature distribution is maintained across the display device.