Birefringence Optical Sheet for LCD Light Concentration
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Solution Overview
Problem
Liquid crystal display (LCD) devices face issues with light concentration efficiency due to the split or collapse of prism patterns between the light guide plate and prism sheet, leading to uneven brightness and the 'white spot phenomenon, especially under external impacts.
Innovation Solution
A birefringence optical sheet with first prism mountains of low refractive index and second prism mountains of higher refractive index is interposed between the liquid crystal panel and the light guide plate, optimizing the refractive angles to prevent pattern splits and enhance light concentration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer prism sheet is used, then the structure is simple, but light concentration efficiency is poor and pattern splits easily under external impact
Solution Approach 1:
The single-layer prism sheet is divided into two separate layers: a lower prism sheet with first prism mountains and an upper prism sheet with second prism mountains. This segmentation allows each layer to perform specific optical functions independently, improving light concentration efficiency while reducing pattern split through the distribution of mechanical stress across multiple layers.
Solution Approach 2:
The invention uses composite prism sheet structure combining two different prism patterns with different refractive indices. The lower prism sheet has a first refractive index and the upper prism sheet has a second refractive index, creating a composite optical system that optimizes both light concentration and structural stability under external impact.
2Productivity
If the refractive index is increased to improve light concentration, then light concentration efficiency improves, but the risk of pattern split and white spot phenomenon increases
Solution Approach 1:
Different regions of the optical system are assigned different refractive indices: the lower prism sheet has a first refractive index optimized for initial light concentration, while the upper prism sheet has a second refractive index optimized for final light direction control. This local quality differentiation allows each region to contribute to light concentration without any single region bearing excessive optical stress that would cause pattern split.
Solution Approach 2:
The invention changes the refractive index parameter across different layers rather than using a uniform high refractive index throughout. By gradiently distributing refractive index values from the lower to upper layers, the system achieves high overall light concentration efficiency while preventing the concentration of mechanical stress that would lead to pattern split and white spot phenomenon.
3Ease of operation
If a prism light guide plate is used, then light can be emitted from the side surface, but friction with the reflective plate causes pattern collapse
Solution Approach 1:
The invention introduces a protective layer between the prism light guide plate and the reflective plate beforehand. This protective layer acts as a cushion that prevents direct friction and mechanical contact between the prism pattern and the reflective plate, thereby preventing pattern collapse while maintaining the light emission capability from the side surface.
Solution Approach 2:
A protective intermediate layer is introduced between the prism light guide plate and the reflective plate to mediate their interaction. This intermediary layer prevents direct mechanical contact and friction between the two components, protecting the prism pattern integrity while allowing the light emission function to continue operating effectively.
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 solution effectively prevents pattern splits and improves light concentration, ensuring uniform brightness and enhanced image quality by refracting light perpendicular to the liquid crystal panel, thus overcoming the limitations of existing LCD devices.
Implementation Method 1
a birefringence optical sheet disposed between the liquid crystal panel and the light guide plate, and the birefringence optical sheet having a first prism pattern with a first refractive index, the pattern facing the liquid crystal panel, and a second prism pattern with a second refractive index higher than the first refractive index, the pattern facing the light guide plate
Data Source
AI summary
A liquid crystal display device capable of preventing a split between a light guide plate and a prism sheet disposed at an upper side thereof and improving concentration efficiency, the device including a liquid crystal panel configured to represent an image, a lamp disposed below the liquid crystal panel to provide light to the liquid crystal panel, a light guide plate having the lamp disposed at least at one side thereof, and a birefringence optical sheet disposed between the liquid crystal panel and the light guide plate, and having a first prism pattern with a first refractive index, the pattern facing the liquid crystal panel, and a second prism pattern with a second refractive index higher than the first refractive index, the pattern facing the light guide plate.