Backlight Unit Reflection Ring for Uniform Luminance
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Solution Overview
Problem
Existing backlight units face challenges in achieving uniform luminance, particularly due to non-uniform light distribution and reflection characteristics.
Innovation Solution
A backlight unit design incorporating a substrate with a light source, lenses, a reflection sheet with through holes, and a reflection ring with a sidewall facing the light source, where the reflection ring has a higher reflectance than the substrate and specific geometric configurations to enhance light reflection and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional backlight unit uses a simple substrate without additional reflection structures, then the device complexity is low, but the luminance uniformity is poor due to non-uniform light distribution
Solution Approach 1:
The reflection structure is divided into two distinct components: a reflection sheet with through holes for light transmission and a reflection ring with opening portions for light reflection. This segmentation allows each component to perform its specific function optimally - the reflection sheet distributes light uniformly while the reflection ring redirects lateral light, achieving luminance uniformity without excessive complexity
Solution Approach 2:
The reflection ring acts as an intermediary element between the light source and the display panel. It receives light that would otherwise be lost laterally and redirects it toward the display panel, serving as a mediator that improves overall light distribution uniformity without requiring complete redesign of the backlight structure
2Illumination intensity
If the reflection ring has high reflectance to improve light distribution, then luminance uniformity improves, but light loss increases due to multiple reflections
Solution Approach 1:
Different regions of the reflection structure have different optical properties: the reflection sheet has high reflectance for lateral light redirection, while the through hole regions allow light transmission. The reflection ring has high reflectance specifically at its opening portions to redirect lateral light, while maintaining transparency where needed. This local differentiation of optical properties achieves uniform luminance while minimizing overall light loss
Solution Approach 2:
The reflection sheet is designed with through holes creating a porous structure that allows light to pass through while the reflection ring provides reflective surfaces. This porous configuration enables selective light transmission and reflection, improving luminance uniformity while preventing complete light trapping that would cause energy loss
3Illumination intensity
If the reflection ring is added to improve light distribution, then luminance uniformity improves, but the manufacturing precision requirements increase
Solution Approach 1:
By segmenting the reflection function into a reflection sheet with through holes and a separate reflection ring with opening portions, each component can be manufactured independently with standard precision. The through holes in the reflection sheet and the opening portions in the reflection ring are designed to align naturally with the light source position, reducing the need for high-precision alignment during assembly
Solution Approach 2:
The reflection ring serves multiple functions: it reflects lateral light toward the display panel, provides structural support for the light source, and defines the optical boundary of the backlight unit. This multi-functionality reduces the need for additional separate components, thereby reducing overall manufacturing complexity and precision requirements
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 design improves luminance uniformity by effectively redirecting and distributing light, resulting in a more uniform and efficient backlight unit performance.
Implementation Method 1
a reflection ring comprising an opening portion corresponding to the at least one light source, and placed between the lens and the substrate
Implementation Method 2
a reflection sheet in which at least one through hole corresponding to the lens is formed
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
Disclosed herein are a backlight unit and a display device using the same. In an embodiment, the backlight unit includes a substrate, at least one light source on the substrate, a lenses placed over the light source, a reflection sheet in which at least one through hole corresponding to the lens is formed, and a reflection ring comprising an opening portion corresponding to the at least one light source, and placed between the lens and the substrate. In accordance with an embodiment of the present invention, luminance uniformity of the backlight unit can be improved because the reflection ring surrounding the light source is included.