Backlight Unit Light Mixing Layer for LCD Color Uniformity
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Solution Overview
Problem
Conventional backlight units for LCD devices face challenges in achieving color and brightness uniformity, particularly with LEDs, which struggle to display pure white images due to uneven color mixing and brightness distribution.
Innovation Solution
A backlight unit comprising multiple unit groups of LEDs with a light mixing layer, structured to disperse and mix red, green, and blue light emitted from LEDs, enhancing color and brightness uniformity by refracting light through a semi-spherical light mixing layer with specific materials and arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If R, G, and B LEDs are arranged in a stripe form to provide partial brightness control and original color reproduction, then color reproduction capability is improved, but color uniformity deteriorates due to uneven mixing of R, G, B light
Solution Approach 1:
A light mixing layer is introduced as an intermediary component between the LED array and the display panel. This layer contains scattering particles that mediate the interaction between the emitted LED light and the surrounding medium, causing multiple scattering events that uniformly distribute R, G, and B light across the display area, thereby achieving both color reproduction and color uniformity
Solution Approach 2:
The refractive index of the light mixing layer is specifically designed to be higher than that of the encapsulating resin (e.g., epoxy resin with refractive index 1.5-1.6). This parameter change optimizes the scattering effect of the particles within the light mixing layer, enhancing light diffusion and uniformity while maintaining color accuracy
2Ease of operation
If LEDs are used as optical source to provide partial brightness control, then brightness control capability is improved, but brightness uniformity deteriorates due to inferior color mixing
Solution Approach 1:
The light mixing layer acts as a mediator that receives light from individual LED control groups and redistributes it uniformly across the display panel. The scattering particles within this layer ensure that even though LEDs are controlled independently for brightness adjustment, the resulting light distribution remains uniform across the entire display area
Solution Approach 2:
The light mixing layer introduces a new dimensional aspect to light distribution by creating a three-dimensional scattering medium. This allows light to be redistributed not just in the plane of the LED array but also in the vertical dimension, achieving superior brightness uniformity across the display surface
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 mixes and distributes light to achieve improved color and brightness uniformity, resulting in better picture quality for LCD devices by ensuring uniform light emission across the panel.
Implementation Method 1
a light mixing layer formed over the unit groups, for mixing lights emitted from the LEDs to provide substantially white light
Implementation Method 2
structured to disperse and mix red, green, and blue light emitted from LEDs, enhancing color and brightness uniformity by refracting light through a semi-spherical light mixing layer
Data Source
AI summary
A backlight unit as embodied includes a plurality of unit groups, each unit group having a plurality of light emitting diodes (LEDs); and a light mixing layer formed over the unit groups, for mixing lights emitted from the LEDs to provide substantially white light.