Edge-Lit Backlight Apparatus with RGB LED Row
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Solution Overview
Problem
Conventional backlight apparatuses using LEDs for large liquid crystal panels face challenges in achieving sufficient brightness and high color purity while maintaining a low profile, as they require extensive space for mixing red, green, and blue lights, leading to increased thickness and environmental concerns due to the use of mercury in fluorescent lamps.
Innovation Solution
A low-profile edge-lit backlight apparatus using a light guiding plate with a row of red, green, and blue LEDs arranged perpendicularly to the plate, allowing for efficient mixing of lights without the need for additional space, resulting in high color purity and brightness, and utilizing LEDs as a safer, environmentally friendly light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If red, green, and blue LEDs are arranged in a row perpendicular to the light guiding plate, then the number of LEDs can be increased three times, but the device complexity increases
Solution Approach 1:
The patent transitions from arranging LEDs in a linear row to a two-dimensional matrix arrangement on the light guiding plate. This dimensional change allows significantly more LEDs to be positioned within the same footprint area, tripling the light output capacity without proportionally increasing the device's linear dimensions.
Solution Approach 2:
The light guiding plate is divided into multiple regions with different refractive indexes, creating distinct light guiding paths for red, green, and blue wavelengths. This segmentation allows each color channel to be independently optimized and controlled, managing the complexity of handling three separate LED types.
2Measurement precision
If a light guiding plate is used to mix red, green, and blue lights, then the thickness of the apparatus increases, but the light mixing efficiency improves
Solution Approach 1:
The patent modifies the refractive index parameter of the light guiding plate material to optimize light mixing efficiency. By carefully selecting and adjusting this optical parameter, the plate achieves effective color mixing with minimal thickness, resolving the contradiction between color purity and apparatus thickness.
Solution Approach 2:
The light guiding plate acts as an intermediary element between the LED array and the liquid crystal panel. It performs the function of light distribution and color mixing in a single integrated component, eliminating the need for separate mixing mechanisms and reducing overall apparatus thickness.
3Loss of energy
If fluorescent tubes are used as light sources, then the luminous efficiency is high, but environmental harm is caused due to mercury content
Solution Approach 1:
The patent employs LEDs, which are solid-state light sources without mercury content. Although individual LEDs have shorter lifetimes compared to fluorescent tubes, their environmental safety and lack of hazardous materials make them the preferred choice, eliminating mercury pollution while maintaining acceptable luminous efficiency through optimized LED arrangement.
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 enables a compact, high-brightness, and high-color-purity backlight system that effectively illuminates large liquid crystal panels, promoting safety and reducing environmental impact by eliminating the need for mercury-based light sources.
Implementation Method 1
a light guiding plate which guides light introduced from a side by means of total reflection on a light emitting surface as one principal surface and a light reflecting surface as the other principal surface and emits light from the light emitting surface based on surface emitting
Implementation Method 2
a color mixing means for generating white light by mixing the first primary color light emitted from the first light emitting diode, the second primary color light emitted from the second light emitting diode, and the third primary color light emitted from the third light emitting diode
Implementation Method 3
a first light emitting diode to emit first primary color light, a second light emitting diode to emit second primary color light, and a third light emitting diode to emit third primary color light
Data Source
AI summary
A low-profile edge-lit backlight apparatus includes a light guiding plate which guides light introduced from a side by utilizing total reflection on a light emitting surface as one principal surface and a light reflecting surface as the other principal surface and emits light from the light emitting surface based on surface emitting, and a plurality of white light emission units that emit white light incident on the light guiding plate. The white light emission section includes a light source group of a first light emitting diode to emit first primary color light, a second light emitting diode to emit second primary color light, and a third light emitting diode to emit third primary color light which are arranged in a row, and a color mixing section that generates white light by mixing the first primary color light, the second primary color light, and the third primary color light.