Backlight Module Waveguide Thermal Expansion Protection
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Solution Overview
Problem
The expansion of the waveguide in a liquid crystal display device's backlight module can cause it to abut against the LED light source, potentially damaging the light source and reducing the service life of the module due to the narrow gap between the waveguide and the LED light strip.
Innovation Solution
A backlight module design featuring a waveguide with a light emitting surface, an incident surface, and a bottom surface, where a heat dissipating frame with a carrying portion and sidewall includes openings adjacent to the sidewall, allowing light sources to be offset from these openings, and a backframe with erections that pass through these openings, ensuring the waveguide's expansion does not contact the light sources, and a reflective film is used to increase air contact and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the LED light strip is arranged on the heat dissipating frame facing the waveguide with a narrow gap to ensure proper coupling and prevent mura effect, then the light distribution uniformity is improved, but the waveguide expansion due to heat will cause contact with the LED light strip, reducing reliability
Solution Approach 1:
The patent introduces an intermediary component (spacers or positioning structures) between the waveguide and the heat dissipating frame to maintain a precise gap. This intermediary element prevents direct contact while ensuring proper light coupling, thus resolving the contradiction between maintaining narrow gap for uniformity and preventing contact for reliability.
Solution Approach 2:
The patent carefully controls and optimizes the gap parameter between the waveguide and LED light strip. By precisely setting this parameter within a specific range, the design achieves both adequate light coupling for uniformity and sufficient clearance to prevent contact during thermal expansion, thus resolving the contradiction.
2Productivity
If the waveguide is positioned close to the LED light strip to prevent mura effect, then the light coupling efficiency is improved, but the thermal expansion of the waveguide will abut against the LED light strip, causing damage
Solution Approach 1:
The patent implements beforehand cushioning by designing the heat dissipating frame with features that accommodate thermal expansion before damage can occur. The frame structure includes expansion compensation mechanisms that absorb the thermal growth of the waveguide, preventing it from contacting the LED light strip and causing damage.
Solution Approach 2:
The patent segments the positioning function by separating the light coupling function (waveguide to LED distance) from the thermal management function (heat dissipating frame structure). This segmentation allows independent optimization of each function, enabling close positioning for efficient coupling while maintaining structural clearance through the segmented frame design.
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 design prevents the waveguide from contacting the light sources during expansion, protecting them from damage and extending the service life of the backlight module by effectively managing heat dissipation and preventing the mura effect.
Implementation Method 1
A reflective film is arranged closely to the bottom surface of the waveguide... increase the surface area of the reflective film in contacting with air
Data Source
AI summary
The present invention discloses a backlight module which can be incorporated within the liquid crystal display device, and which includes a waveguide, a heat dissipating frame, a light source and a backframe. The heat dissipating frame includes a carrying portion and a sidewalk. The carrying portion abuts against a bottom surface of the waveguide. The carrying portion is defined with openings in an area adjacent to the sidewalk. The light source is mounted onto the sidewall and offset to the opening. The backframe includes a bottom board and erections which extend and pass through the opening. The bottom board abuts the carrying portion. The thickness of the erection is larger than the thickness of the light source such that expansion of the waveguide exposed under heat will not in contacting with the light source. Accordingly, the light source will not be damaged by the expansion of the waveguide, and therefore prolong the service of the light source.