Glass Light Guide Plate for LCD Displays
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Solution Overview
Problem
Conventional light guide plates made of PMMA exhibit poor mechanical properties such as rigidity, coefficient of thermal expansion (CTE), and moisture absorption, which pose challenges in large-size LCD displays, and also have limitations in optical performance like light coupling and solarization.
Innovation Solution
A glass light guide plate with a specific composition comprising greater than 74 mol% SiO2, between 3-6 mol% Al2O3, and 0-3.5 mol% B2O3, with controlled alkali and alkaline earth oxides, and low iron concentration, is used to enhance mechanical and optical performance, allowing for improved rigidity, reduced moisture sensitivity, and efficient light coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PMMA plastic materials are used for light guide plates, then light transmission is excellent, but mechanical properties such as rigidity, coefficient of thermal expansion and moisture absorption are poor
Solution Approach 1:
The patent applies composite materials by creating a glass composition that combines multiple oxide components (SiO2, Al2O3, B2O3, and metal oxides) to achieve both excellent optical transmission and superior mechanical properties. The glass composite integrates the light transmission benefits of plastic materials with the mechanical strength and thermal stability of glass materials, resolving the contradiction between optical performance and mechanical properties.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the chemical composition parameters of the glass material, including SiO2 content (50-70 wt%), Al2O3 content (10-20 wt%), B2O3 content (5-15 wt%), and various metal oxide additives. By optimizing these compositional parameters, the invention achieves the desired balance between light transmission and mechanical properties.
2Ease of manufacture
If conventional plastic materials are used, then manufacturing is easier, but optical performance in terms of solarization, scattering and light coupling is limited
Solution Approach 1:
The patent uses parameter changes by controlling the chemical composition parameters, particularly the addition of specific metal oxides (Fe2O3: 0.01-5 wt%, TiO2: 0.01-5 wt%, ZnO: 0.01-5 wt%) that directly influence optical properties. These compositional adjustments enable the glass material to achieve superior optical performance regarding solarization resistance, light scattering control, and light coupling efficiency while maintaining manufacturability.
3Strength
If glass materials are used to improve mechanical properties, then rigidity and thermal stability improve, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing the glass composition to use common, cost-effective raw materials such as silica sand, alumina, and boric acid. The controlled addition of inexpensive metal oxides (Fe2O3, TiO2, ZnO) allows achievement of desired mechanical and optical properties without significantly increasing material cost or manufacturing complexity.
Solution Approach 2:
The patent employs this principle by using abundant, inexpensive natural materials as the base composition (silica sand, alumina, boric acid) rather than rare or expensive specialty materials. This approach reduces raw material costs while still achieving the required performance specifications through careful compositional control.
Data Source
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AI summary
Compounds, compositions, articles, devices, and methods for the manufacture of light guide plates and back light units including such light guide plates made from glass. In some embodiments, light guide plates (LGPs) are provided that have similar or superior optical properties to light guide plates made from PMMA and that have exceptional mechanical properties such as rigidity, CTE and dimensional stability in high moisture conditions as compared to PMMA light guide plates.