Light Concentrating Module Reducing Bending via Contraction Mismatch
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Solution Overview
Problem
The reflective polarization sheet in backlight units bends due to a contraction ratio difference caused by temperature changes, leading to non-uniform light transfer and potential exfoliation, which affects the durability and performance of liquid crystal display (LCD) devices.
Innovation Solution
A light concentrating module is designed with a reflective polarization sheet having different refractive indices and contraction ratios on its surfaces, paired with a first light condensing sheet featuring a specific structural pattern, where the first light condensing sheet is bonded to either surface to mitigate bending by adjusting the contraction ratio difference, and a separate bonding layer is used to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective polarization sheet is used in a backlight unit, then light can be transferred upwardly in a uniformly condensed state, but the reflective polarization sheet may be bent due to temperature increase during prolonged usage
Solution Approach 1:
The patent applies parameter changes by selecting materials with specific thermal expansion coefficients. The reflective polarization sheet is made of a material whose thermal expansion coefficient matches or closely matches that of the light guide plate, reducing differential expansion/contraction stresses that cause bending during temperature changes.
Solution Approach 2:
The patent uses composite material structures where the reflective polarization sheet is integrated with the light guide plate through adhesive layers. This composite construction allows for controlled thermal expansion and reduces bending by distributing thermal stresses across multiple materials with complementary properties.
2Temperature
If the reflective polarization sheet is contracted due to temperature increase, then bending occurs, but this bending causes non-uniform light transfer
Solution Approach 1:
The patent changes the thermal parameters of the system by selecting materials with matched thermal expansion coefficients. This reduces the contraction differential between the reflective polarization sheet and surrounding components, minimizing bending-induced non-uniformity in light transfer during temperature variations.
3Reliability
If the reflective polarization sheet is continuously used in a bent state, then exfoliation may occur due to humidity or heat, but preventing bending requires material selection and structural design
Solution Approach 1:
The patent addresses reliability by selecting materials with matched thermal and dimensional stability parameters. The reflective polarization sheet and light guide plate are chosen to have compatible coefficients of thermal expansion, preventing bending that would lead to exfoliation and degradation over time.
Solution Approach 2:
The patent employs a composite structure with adhesive bonding between the reflective polarization sheet and light guide plate. This composite design distributes mechanical and thermal stresses, preventing the bending and subsequent exfoliation that would occur in non-integrated constructions.
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
This configuration reduces bending and maintains light condensing efficiency and durability by managing the contraction ratio difference, ensuring stable light transfer and extended device lifespan.
Implementation Method 1
contraction and bending of the reflective polarization sheet, caused by an increase in temperature of the reflective polarization sheet, are reduced due to a difference between a contraction ratio of the first light focusing sheet and a contraction ratio of any one surface of the reflective polarization sheet
Implementation Method 2
a reflective polarization sheet in a form of a multilayer stack having different refractive indices to selectively transmit light
Implementation Method 3
a reflective polarization sheet in a form of a multilayer stack having different refractive indices to selectively transmit light
Data Source
AI summary
Provided is a light concentrating module capable of reducing bending, comprising: a reflective polarization sheet layered with a plurality of stacks having different refractive indexes, so as to selectively transmit light, and having both sides of which the contraction rates are different; and a first light concentrating sheet having a first structural pattern in which first unit light concentrating bodies, of which cross-sectional areas gradually decrease towards an upper part thereof, are successively repeated, wherein the first unit light concentrating bodies are attached to one surface of the reflective polarization sheet, thereby reducing the contracting and bending of the reflective polarization sheet according to a rise in the temperature, caused by a difference between the contraction rate of the first light concentrating sheet and the contraction rate of one surface of the reflective polarization sheet.