Rectangular Reflectors with Rounded Corners for Backlight Uniformity
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Solution Overview
Problem
Direct-lit backlights face challenges in achieving uniform brightness and minimizing display thickness due to optical losses and alignment issues with conventional circular reflectors, which lead to undesirable hot spots and increased thickness.
Innovation Solution
The use of rectangular reflectors with rounded corners, optically coupled to a light guide plate and a reflective layer, improves light distribution and alignment tolerance, allowing for thinner backlights with uniform brightness and reduced optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional circular reflectors are used in direct-lit backlights, then light distribution is achieved, but hot spots occur and alignment precision is poor
Solution Approach 1:
The patent applies curvature by using rounded corners on rectangular reflectors instead of sharp corners or circular shapes. This curved geometry at the corners improves light scattering and eliminates hot spots while maintaining alignment tolerance, directly resolving the contradiction between light distribution uniformity and alignment precision
Solution Approach 2:
The patent applies different geometric properties to different parts of the reflector: rectangular sides for maintaining alignment structure and rounded corners for improving light distribution. This local differentiation allows the reflector to simultaneously achieve good alignment precision and uniform light distribution without hot spots
2Illumination intensity
If diffuser plate is positioned at a distance from LEDs to achieve uniform brightness, then light uniformity improves, but display thickness increases
Solution Approach 1:
The patent introduces a new spatial dimension by positioning reflectors in a plane parallel to the light guide plate at an optimized distance. This allows light redistribution to occur in a different dimensional plane, achieving brightness uniformity without increasing the vertical thickness of the display assembly
3Length of stationary object
If optical distance between LEDs and diffuser plate is reduced to decrease backlight thickness, then display thickness decreases, but optical losses increase
Solution Approach 1:
The patent introduces reflectors as intermediary elements between the LEDs and the light guide plate. These reflectors mediate the light path by reflecting and redistributing light over longer distances, enabling effective light utilization even when the optical distance is reduced, thus preventing optical losses while maintaining thin backlight design
4Manufacturing precision
If rectangular reflectors with rounded corners are used, then alignment tolerance improves and hot spots are reduced, but manufacturing complexity increases
Solution Approach 1:
The rounded corners are designed with practical radius values that balance the need for improved alignment tolerance and hot spot reduction against manufacturing simplicity. The curvature is sufficient to achieve the optical benefits but not so complex as to significantly increase fabrication difficulty or cost
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 results in thinner, more efficient direct-lit backlights with improved alignment tolerance and reduced hot spots, achieving uniform brightness across the display.
Implementation Method 1
a reflective layer, The reflective layer is on the substrate
Implementation Method 2
a light guide plate proximate the plurality of light sources
Implementation Method 3
a light guide plate proximate the plurality of light sources and includes a pattern of light extractors
Data Source
AI summary
A backlight includes a substrate, a plurality of light sources, a light guide plate, and a plurality of rectangular reflectors including rounded corners. The plurality of light sources are proximate the substrate. The light guide plate is proximate the plurality of light sources. The plurality of rectangular reflectors including rounded corners are in a plane parallel to the light guide plate and each reflector corresponds to a light source.