Backlight Unit Hole Luminance Uniformity
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Solution Overview
Problem
The presence of holes in LCD devices creates uneven luminance values between the front and behind the hole due to the uneven light distribution from the backlight unit, resulting in lower image quality.
Innovation Solution
Optimal placement and angle of light sources, combined with a cut-out section in the light guide plate and the use of reflector tape and band to redirect light and prevent escape through the hole, ensuring even luminescence around the hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hole is provided in the LCD device to allow material or parts to pass through, then the device can accommodate additional components or materials, but the luminance values become uneven between the front of the hole and behind the hole, resulting in lower image quality
Solution Approach 1:
The patent applies local quality by providing a reflector band specifically around the inner periphery of the hole to reflect light that would otherwise escape through the hole walls. This localized reflection structure ensures that the region around the hole receives adequate light, maintaining uniform luminance across the entire display surface including the hole area, while not affecting other regions of the display device.
Solution Approach 2:
The reflector band acts as an intermediary element between the light guide plate and the hole. It intercepts light traveling toward the hole walls and redirects it back into the light guide plate, preventing light loss and ensuring that the hole does not create a luminance defect. This intermediary structure resolves the conflict between having a hole for component accommodation and maintaining uniform illumination.
2Illumination intensity
If light sources are positioned closer to the hole to increase light intensity around the hole, then luminance around the hole improves, but light distribution uniformity across the entire display surface becomes uneven
Solution Approach 1:
The patent segments the light distribution function by using multiple light sources arranged in a linear array along one edge of the light guide plate, with each light source contributing to different regions. The reflector band further segments the light path by specifically addressing the hole region. This segmentation allows optimized light distribution where needed (around the hole) while maintaining overall uniformity across the entire display surface.
Solution Approach 2:
The patent addresses the light distribution problem by adding a dimensional element - the reflector band is positioned in three-dimensional space around the hole periphery, creating a spatial light reflection path. This dimensional approach allows light to be redirected from multiple angles into the hole region without requiring light sources to be positioned too close, thereby maintaining both local luminance and global 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
Significantly reduces the luminance difference between the front and behind the hole, enhancing image quality by distributing light more uniformly across the display device.
Implementation Method 1
The reflector tape reflects the light incident to the second edge of the light guide plate
Implementation Method 2
the reflector band reflects the light incident to the walls of the hole, preventing light from escaping through the walls of the hole
Implementation Method 3
The reflector sheet reflects the light transmitted through the rear surface of the light guide plate to the upper surface thereof
Data Source
AI summary
A display device with at least one hole is susceptible to poor image quality because of the luminance difference between the front of the hole and behind the hole in relation to the plurality of light sources located along one edge of the backlight unit. To decrease the luminance difference, the distance between adjacent light sources are adjusted, the light ray directions are altered and cutout sections are provided.