Backlight Module Light Mixing Space Design
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Solution Overview
Problem
Conventional LED backlight modules for LCDs face challenges in achieving cost-effective and efficient light mixing, leading to increased complexity and cost, while also requiring better heat dissipation and color saturation, and often rely on specific wavelength ranges which limit their performance.
Innovation Solution
A backlight module design incorporating a light guide plate with a light source positioned on one side and a diffuser sheet without direct contact, featuring a light mixing space between the plate and the diffuser to ensure thorough light mixing before emission, allowing for reduced LED count, improved heat dissipation, and expanded wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LED sources are positioned uniformly in the backlight module to achieve uniform brightness, then the light utility efficiency is improved and heat dissipation is better, but the cost of the backlight module increases
Solution Approach 1:
A light mixing plate is introduced as an intermediary component between the LED light source and the diffuser sheet. This plate performs the light mixing function that would otherwise require multiple distributed LED sources, thereby reducing the number of LEDs needed while maintaining uniform brightness output.
Solution Approach 2:
The light mixing function and the light guiding function are merged into a single light mixing plate component. This consolidation reduces the total number of components needed in the backlight module, simplifying the structure and reducing cost while achieving uniform light distribution.
2Illumination intensity
If a light mixing space is positioned between the light guide plate and the diffuser sheet to ensure thorough light mixing, then the color saturation is improved, but the thickness of the backlight module increases
Solution Approach 1:
The light mixing plate serves multiple functions simultaneously: it acts as a light mixing medium to improve color saturation, functions as a light guiding element to distribute light uniformly, and serves as a structural support component. This multi-functionality allows achieving good light mixing without proportionally increasing thickness.
Solution Approach 2:
The refractive index parameters of the light mixing plate are optimized to enhance light mixing efficiency within a limited thickness. By carefully selecting and controlling the refractive index of the plate material, effective light mixing is achieved in a compact space, balancing color saturation improvement with thickness constraints.
3Length of stationary object
If the diffuser sheet is positioned close to the light guide plate to reduce thickness, then the overall size is reduced, but the light cannot mix sufficiently before emission
Solution Approach 1:
The light mixing plate is positioned between the light guide plate and the diffuser sheet to act as an intermediary that enables sufficient light mixing in a compact space. This intermediary component ensures that light from different LED sources mixes thoroughly before reaching the diffuser sheet, maintaining light mixing uniformity while keeping the overall thickness reduced.
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 achieves uniform brightness and better color saturation with reduced costs by optimizing light distribution and heat management, mimicking the performance of traditional cold cathode fluorescent lamps while being more environmentally friendly.
Implementation Method 1
A light guide plate having a light-exit face and at least a light-incidence face, wherein the light emitted from the light source enters the light guide plate from the light-incidence face
Implementation Method 2
A diffuser sheet is placed on the CCFL to provide planar light with uniform brightness
Data Source
AI summary
A backlight module includes a light guide plate, a light source disposed at a side of the light guide plate, a diffuser sheet positioned over the light guide plate but not directly contacting the light guide plate, and a light mixing space positioned between the light guide plate and the diffuser sheet so that light emitted from the light guide plate mixes in the light mixing space before being emitted out of the backlight module.