Low-Birefringence Resin Light Guide Plate for Polarization Disturbance
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Solution Overview
Problem
Conventional light guide plates and polarized light sources in liquid crystal displays suffer from birefringence-induced polarization characteristic disturbances, leading to reduced light transmission efficiency and display brightness due to residual stress in resin materials during manufacturing.
Innovation Solution
The use of low-birefringence light transmissive resins with retardation one-fourth or less of the polarized light wavelength for both the light guide plate and the sealing portion of the polarized light source, which suppresses polarization disturbances and maintains the polarization characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resin materials are used for light guide plates and sealing portions, then manufacturing is easier and cost is lower, but birefringence occurs due to molecular orientation and residual stress during molding and curing, which disturbs polarization characteristics and reduces light transmission efficiency
Solution Approach 1:
The patent changes the material parameter by selecting resin materials with inherently low birefringence properties. Specifically, it uses resin materials where the product of birefringence and thickness is 50 nm or less, fundamentally altering the optical parameter to prevent polarization disturbance while maintaining conventional molding processes
Solution Approach 2:
The patent employs composite material strategies by combining resin materials with specific low birefringence characteristics and controlling the molecular orientation structure. It creates a composite system where the resin matrix and oriented molecules work together to minimize birefringence effects while maintaining structural integrity and ease of manufacturing
2Use of energy by moving object
If polarized light sources are used in liquid crystal displays, then light utilization efficiency should be enhanced, but the polarization characteristics are disturbed by birefringence in the light guide plate and sealing resin, causing the polarized light to become random polarized light
Solution Approach 1:
The patent changes the optical parameter of the resin material by selecting materials with low birefringence and controlling the thickness-product of birefringence to be 50 nm or less. This parameter change ensures that polarized light maintains its polarization characteristics after passing through the light guide plate and sealing portions, thereby preserving light utilization efficiency
Solution Approach 2:
The patent converts the potentially harmful effect of resin molecular orientation into a beneficial outcome by carefully controlling the orientation process during molding. Instead of preventing orientation entirely, it utilizes the orientation to create a structured composite material that minimizes birefringence while maintaining manufacturing advantages, thus converting what would be a harmful distortion into a controlled feature
3Strength
If resin materials undergo thermal curing after molding, then sealing and structural integrity are improved, but residual stress and molecular orientation occur, generating birefringence that attenuates light intensity by approximately 35% after passing through polarizing plates
Solution Approach 1:
The patent changes the material selection parameter by choosing resin compositions that exhibit low birefringence characteristics even after thermal curing. It specifies that the product of birefringence and thickness should be 50 nm or less, which allows the resin to maintain both sealing integrity through proper curing while minimizing light attenuation
Solution Approach 2:
The patent applies local quality control by managing the curing process and molecular orientation in specific regions of the light guide plate and sealing portions. It ensures that areas critical for light transmission have optimized material properties with minimal birefringence, while maintaining overall structural integrity and sealing performance through controlled local material characteristics
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 approach enhances light transmission efficiency, increases the quantity of polarized light passing through polarizing plates, and improves display brightness and contrast, potentially reducing the need for polarizing plates and lowering power consumption in liquid crystal displays.
Implementation Method 1
the light guide plate being made of light transmissive resin having low birefringence in which retardation is one-fourth or less of a wavelength of the polarized light
Implementation Method 2
a polarized light source that emits polarized light; and a light guide plate including a light incident surface on which the polarized light emitted from the polarized light source is made incident
Data Source
AI summary
A surface light emitting device includes a polarized light source that emits polarized light; and a light guide plate including a light incident surface on which the polarized light emitted from the polarized light source is made incident, and a light emitting surface that emits light, the light guide plate being made of light transmissive resin having low birefringence in which retardation is one-fourth or less of a wavelength of the polarized light.