Backlight Module Refractive Surface for LCD Brightness Uniformity
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Solution Overview
Problem
Existing backlight modules with LEDs suffer from corner vignette issues due to limited light emitting angles, resulting in uneven brightness distribution across liquid crystal display panels.
Innovation Solution
A backlight module design featuring a waveguide with chamfered corners and a refractive surface adjacent to a spot light source, where the light beam from the spot light source is directed toward the refractive surface, allowing for wider light entry angles and improved evenness of brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the LED is arranged on the corner of the waveguide facing directly toward the incident surface, then the light emitting angle is increased, but the corner vignette occurs and brightness evenness deteriorates
Solution Approach 1:
A refractive surface is introduced as an intermediary component between the LED and the waveguide. This refractive surface refracts the light beam emitted from the LED, changing its propagation angle before it enters the waveguide. By controlling the refraction, the light can be directed to enter the waveguide at optimal angles that avoid corner vignette while maintaining broad illumination coverage and even brightness distribution.
Solution Approach 2:
The refractive index of the refractive surface is carefully selected to control the light bending effect. By adjusting this optical parameter, the light beam's angle of incidence into the waveguide is modified, transforming the illumination pattern to eliminate corner darkening while preserving overall brightness uniformity across the display panel.
2Illumination intensity
If more than scores of LED are arranged along the side of the waveguide, then bright illumination is provided, but the device complexity increases
Solution Approach 1:
Instead of using many LEDs arranged along the waveguide side, the solution segments the illumination function into a single LED positioned at the corner combined with a refractive surface. This segmentation approach consolidates multiple light sources into one strategically positioned source with optical assistance, reducing component count while maintaining illumination effectiveness.
Solution Approach 2:
The solution transitions from a linear arrangement of multiple LEDs along the waveguide side to a corner positioning approach with optical refraction in a different spatial dimension. By utilizing the corner position and refraction geometry, the system achieves broad illumination coverage with fewer components, effectively adding an optical dimension to the illumination strategy.
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 effectively addresses corner vignette issues and enhances the evenness of brightness across the liquid crystal display panel by increasing the light entry angle into the waveguide, resulting in improved illumination uniformity.
Implementation Method 1
the light beam emitted from the spot light source will be directed toward the refractive surface, and then the light beam enters the waveguide after the light beam is refracted by the refractive surface
Data Source
AI summary
The present invention discloses a backlight module which includes a waveguide and a spot light source. Wherein the waveguide includes an incident face and a refractive surface adjacent to the waveguide, the light beam emitted from the spot light source will be directed toward the refractive surface, and then the light beam enters the waveguide after the light beam is refracted by the refractive surface. The present invention also discloses a liquid crystal display device incorporated with the backlight module disclosed. The backlight module can readily improve the corner vignette and enhanced with more evenly distributed brightness across the waveguide. The liquid crystal display device incorporated with the module also enjoy the evenly distributed brightness.