Light Guide Assembly Triangular Prism Anti-Peep
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Solution Overview
Problem
Conventional display devices, such as smartphones, have a wide visual angle, making it possible for others to snoop on information displayed, which is a concern for privacy.
Innovation Solution
A light guide assembly with triangular prism units and specific refractive index layers is used to control light emission, ensuring that light is emitted in a convergent beam only when viewed directly, preventing information from being visible from other angles by using a light guide assembly with a first medium layer, triangular prism units, and a second medium layer, where the refractive indices are carefully managed to control the light's exit angle and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide visual angle is used in display devices, then viewing comfort and coverage are improved, but privacy protection deteriorates as information becomes visible from multiple angles
Solution Approach 1:
The patent applies local quality by creating different optical properties at different locations and viewing angles. The light guide assembly uses triangular prism units with specific refractive indices to create a directional light emission pattern, where the optical characteristics vary depending on the viewing angle, allowing wide coverage in the forward direction while blocking side views for privacy protection
Solution Approach 2:
The patent employs parameter changes by carefully controlling the refractive indices of different layers (n1 for second medium layer, n2 for triangular prism units, n3 for first medium layer) and the angle A of the triangular prisms. By optimizing these parameters according to the formulas provided (where α=arcsin(n1/n2) and β=arcsin(n3/n2)), the system achieves directional light emission that provides wide viewing angle in the intended direction while preventing light leakage at oblique angles
2Ease of manufacture
If conventional light guide structures are used, then manufacturing simplicity is maintained, but light direction control precision is insufficient to achieve anti-peep function
Solution Approach 1:
The patent applies segmentation by dividing the light guide structure into distinct functional layers: a first medium layer, triangular prism units, and a second medium layer. Each layer has specific optical properties and functions, allowing independent optimization of light direction control while maintaining a relatively simple overall structure that can be manufactured using conventional processes
Solution Approach 2:
The patent uses composite materials by combining different medium layers with specific refractive indices (n1, n2, n3) and triangular prism units made from materials like SiNx or glass. This composite structure enables precise control over light emission angles through the interaction of light with different material interfaces, achieving the required angular precision for anti-peep functionality while maintaining manufacturability
3Manufacturing precision
If triangular prism units with high refractive index are used, then light direction control is improved, but device complexity increases due to multiple layers and refractive index matching requirements
Solution Approach 1:
The patent applies universality by designing the triangular prism units to serve multiple functions simultaneously: they act as optical elements for directional light emission, structural components for maintaining layer spacing, and interfaces for total internal reflection. The second medium layer (with refractive index n1) serves both as a protective coating and as an optical medium that participates in the refraction and reflection processes, reducing the need for additional separate components
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 limits the visibility of the display's information to only direct viewing angles, enhancing privacy by ensuring the light is not visible unless observed directly, thus providing an anti-peep function.
Implementation Method 1
refractive index n2 of each of the at least one triangular prism unit is greater than refractive index n3 of the first medium layer and refractive index n1 of the second medium layer
Implementation Method 2
an angle A between the second light incidence face and the second light exit face meets: α+β−10°≤A≤α+β where α=arcsin(n1/n2) and β=arcsin(n3/n2)
Data Source
AI summary
A light guide assembly, a backlight source and a display device are provided. The light guide assembly includes: a first medium layer including a first light incidence face and a first light exit face opposed to each other; at least one triangular prism unit on the first light exit face, each triangular prism unit including a second light incidence face, a second light exit face and a non-exit face, the second light incidence face being in contact with the first light exit face; and a second medium layer covering the second light exit face, refractive index n2 of each triangular prism unit is greater than refractive index n3 of the first medium layer and refractive index n1 of the second medium layer; and wherein an angle A between the second light incidence face and the second light exit face meets: α+β−10°<A<α+β, where α=arcsin(n1/n2) and β=arcsin(n3/n2).