Optical Sheet Structure Using Ultra-Low Index Layer for Total Reflection
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Solution Overview
Problem
Existing optical sheets for light guide plate type liquid crystal displays face reduced light utilization efficiency due to the use of low refractive index layers that are not sufficiently low, leading to inadequate total reflection and increased optical characteristics when integrating optical films without air layers.
Innovation Solution
Incorporating a low refractive index layer with a refractive index of 1.25 or less, integrated via pressure-sensitive adhesive layers, which maintains optical characteristics and reduces thickness without a base, while protecting the layer from physical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If optical films are integrated without an air layer using conventional low refractive index layers, then device thickness is reduced and integration is achieved, but optical characteristics deteriorate due to insufficient total reflection
Solution Approach 1:
The patent changes the refractive index parameter of the low refractive index layer to 1.30 or less (conventional layers have higher refractive indices), which enables sufficient total reflection of oblique incident light while maintaining integration without air layers, thus resolving the contradiction between thickness reduction and optical characteristic maintenance
Solution Approach 2:
The patent uses a composite structure combining a low refractive index layer (with refractive index 1.30 or less) and pressure-sensitive adhesive layers to achieve both integration functionality and optical performance, where the composite material system provides both mechanical bonding and optical reflection functions
2Device complexity
If conventional low refractive index layers are used to integrate optical films, then manufacturing complexity is reduced, but light utilization efficiency decreases due to inadequate total reflection
Solution Approach 1:
By changing the refractive index parameter to 1.30 or less, the patent achieves effective total reflection of oblique incident light, preventing light leakage and improving light utilization efficiency while maintaining simple integrated manufacturing without air layers
3Reliability
If air layers are used as total reflection layers between optical films, then optical characteristics are maintained, but device thickness increases and integration is prevented
Solution Approach 1:
The patent replaces air layers (refractive index ~1.0) with a solid low refractive index layer (refractive index 1.30 or less) that provides equivalent total reflection functionality while enabling physical integration and thickness reduction
Solution Approach 2:
The low refractive index layer serves as an intermediary between optical films, providing both the total reflection function previously requiring air layers and enabling mechanical integration through pressure-sensitive adhesive bonding
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
Enhances optical performance, reduces thickness, and improves assembly yield by integrating optical films without air layers, maintaining transparency and strength through adhesive layers.
Implementation Method 1
oblique incident light is not totally reflected, and retroreflection cannot be used
Data Source
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AI summary
The present invention provides an optical sheet for a light guide plate type liquid crystal display, including a low refractive index layer having an extremely low refractive index. The optical sheet A12 for a light guide plate type liquid crystal display (1000) according to the present invention includes a first optical film (light guide plate) (1010), a low refractive index layer (20), and a second optical film (reflection plate) (1020) laminated in this order, and the low refractive index layer (20) has a refractive index of 1.25 or less.