Backlight Light Guide Plate Color Mixing and Weight Reduction
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Solution Overview
Problem
Conventional backlights using LEDs for liquid crystal display devices face issues with color reproducibility, brightness nonuniformity, and increased weight due to the need for multiple light guide plates, leading to inefficiencies and higher costs compared to cold cathode fluorescent lamps.
Innovation Solution
A backlight design featuring first and second light guide plates with a light source in between, a diffusion plate above, and reflectors to direct light through a hollow area, reducing the number of interfaces and optical losses, and incorporating a separation plate to separate the light guide plates optically, resulting in a thinner, lighter, and more efficient design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple light guide plates are used to mix RGB LED colors, then color uniformity is improved, but device weight and complexity increase significantly
Solution Approach 1:
The patent merges the color mixing function and light guiding function into a single integrated light guide plate structure. The light guide plate contains both light guiding portions (for directing light from LEDs) and color mixing portions (for uniform color distribution), eliminating the need for separate light guide plates for each function and reducing overall weight and complexity.
Solution Approach 2:
The light guide plate is designed to perform multiple functions simultaneously: it guides light from the LED sources, mixes the RGB colors uniformly, and directs light toward the display panel. This multi-functional design replaces what would traditionally require multiple separate components, reducing weight while maintaining color uniformity.
2Stability of the object's composition
If multiple light guide plates with many interfaces are used, then color mixing is achieved, but optical loss increases and light efficiency decreases
Solution Approach 1:
By combining the light guiding and color mixing functions into a single integrated structure, the patent reduces the number of interfaces between different components. The integrated design minimizes reflection and refraction losses at interfaces while still achieving effective color mixing through the designed light paths within the single plate.
3Stability of the object's composition
If conventional backlight structures with multiple components are used, then color mixing is achieved, but device thickness increases
Solution Approach 1:
The patent integrates light guiding, color mixing, and light direction functions into a single thin light guide plate structure. This merging of functions eliminates the need for multiple stacked components (separate light guide plates, reflectors, diffusers), thereby reducing the overall thickness of the backlight unit while maintaining color mixing capability.
Solution Approach 2:
The patent uses two-dimensional light propagation paths within the light guide plate to achieve color mixing, rather than relying on stacking multiple components in the thickness direction. The light travels laterally through different regions of the plate (light guiding portions and color mixing portions), achieving color uniformity without increasing thickness.
4Use of energy by moving object
If LEDs are used as light sources, then energy efficiency is improved, but color reproducibility and brightness uniformity are worsened
Solution Approach 1:
The light guide plate is segmented into light guiding portions and color mixing portions, allowing different regions to perform specialized functions. The light guiding portions efficiently transport light from LED sources, while the color mixing portions ensure uniform color and brightness distribution across the display, thereby maintaining LED energy efficiency while improving 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
This configuration eliminates color and brightness nonuniformity, reduces the area occupied by light guide plates, and enhances light efficiency by minimizing optical losses, making the backlight more suitable for larger applications while maintaining high-quality image display.
Implementation Method 1
The monochromatic light of the colors RGB that enters the light guide plate 102 is propagated inside the light guide plate 102 repeatedly undergoing total reflection
Implementation Method 2
The direction of travel of the light emitted from the LED 101 is changed by roughly 90° at a first reflector 105
Implementation Method 3
The light that is incident to the light guide plate 103 is uniformly emitted from the top surface of the light guide plate 103 through the use of a scattering and reflective pattern disposed on the reverse surface thereof
Data Source
AI summary
A plurality of LEDs are arrayed in a single row between the opposing end faces of a pair of first and second light guide plates that are disposed so that the end faces thereof face each other. A reflective sheet is disposed on the lower surfaces of the pair of first and second light guide plates, and a separation plate is disposed so as to cover the upper surfaces of the first and second light guide plates and the gap therebetween. A reflecting body for guiding light emitted upward from the LEDs to the first and second light guide plates is disposed in the area immediately above the LEDs on the lower surface of the separation plate. A diffusion plate is disposed with a fixed gap above the separation plate, and a hollow area is formed between the diffusion plate and the separation plate.