Liquid Crystal Display Light Guide Plate Protrusions for Color Uniformity
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Solution Overview
Problem
Liquid crystal display devices using white LEDs as backlights often experience color unevenness, particularly a yellowish tint, near the light source due to the varying color conversion of light by yellow fluorescent substances, leading to non-uniform luminance.
Innovation Solution
The implementation of a liquid crystal display device with a light guide plate and white LEDs arranged such that the blue spectrum is denser in the center and the yellow spectrum is denser towards the sides, with incident plane protrusions on the light guide plate to refract light differently based on the color distribution, ensuring a more uniform light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If white LEDs with yellow fluorescent substances are used as backlight light sources, then high luminance efficiency is achieved, but color unevenness (yellowing) occurs near the light source
Solution Approach 1:
The patent applies local quality by creating different surface structures at different locations on the light guide plate. The first surface has a first structure (e.g., microlens array) and the second surface has a second structure (e.g., prism array or different microlens configuration), allowing each surface to selectively control specific wavelengths of light. This local differentiation enables the plate to manage the spectral distribution non-uniformly, correcting the yellowing effect in specific regions while maintaining overall high luminance efficiency.
2Object-affected harmful factors
If incident plane protrusions are added to refract light differently, then color uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple optical functions into a single integrated light guide plate structure. Instead of using separate components for light entry, refraction, and color correction, the invention combines these functions into one element with multiple surfaces having different structures. The first and second surfaces work together within the same light guide plate to achieve both light distribution and color uniformity, reducing the number of discrete components and simplifying the overall device architecture.
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 mitigates the yellowing effect near the light source by effectively scattering and refracting light, resulting in improved color uniformity across the display screen.
Implementation Method 1
an amount of light, refracted on the section corresponding to the area having the dense blue spectrum of the LEDs at the plane of incidence of the light guide plate, is larger than an amount of light refracted in any other areas of the light guide plate
Data Source
AI summary
This invention reduces or prevents a phenomenon where a screen close to a light source becomes yellowed. A liquid crystal display device includes a liquid crystal display panel and a backlight. The backlight includes a light guide plate 10 and white LEDs 21 arrayed in a first direction on a plane of incidence 11 of the light guide plate 10. The white LEDs 21 each includes, in the first direction on a light-emitting surface, a central area occupied by a blue spectrum more densely than at adjacent sides of the central area. Incident plane protrusions 111, each extending in a thickness direction of the light guide plate 10, are formed on a section corresponding to the area having the dense blue spectrum of each LED 21, at the plane of incidence 11 of the light guide plate 10.