Asymmetric Optical Element Light Coupling Efficiency
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Solution Overview
Problem
Existing optical arrangements for light mixing and deflection suffer from efficiency losses when used in downstream systems due to their symmetrical configurations, leading to suboptimal utilization of light.
Innovation Solution
An optical arrangement featuring a first optical element with a light guide cut at an angle, where the light entry surface is formed by the uncut end face and the light exit surface is a region of the wall with a cut surface, and a second optical element with a light entry aperture opposite the exit surface, optimized by specific geometric relationships between the width and height of these surfaces to enhance coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a symmetrical optical element design is used for light mixing, then light mixing performance is improved, but light coupling efficiency into downstream optical systems deteriorates
Solution Approach 1:
The patent applies asymmetry by designing the optical element with a non-symmetrical cross-sectional shape, specifically a rectangular cross-section with different dimensions in the first and second directions. This asymmetric geometry enables optimized light coupling into downstream optical systems while maintaining effective light mixing functionality, resolving the contradiction between symmetric design benefits and coupling efficiency requirements
2Loss of energy
If the light entry aperture size is increased to improve coupling, then light coupling efficiency is improved, but the volume of the second optical element increases
Solution Approach 1:
The patent employs parameter changes by establishing specific dimensional relationships between the light entry aperture and the optical element cross-section. The width x and height z are optimized according to the deflection angle and refractive index, creating an optimal balance between coupling efficiency and component volume without requiring excessive aperture sizes
3Loss of energy
If the width x of the light entry surface is increased to improve coupling, then light coupling efficiency is improved, but the aspect ratio optimization becomes more difficult
Solution Approach 1:
The patent resolves this contradiction by providing explicit mathematical relationships for the aspect ratio optimization. The width x is determined by the formula x = z * cos(α) / n, where z is the aperture height, α is the deflection angle, and n is the refractive index. This parameter-based approach simplifies the design process while maintaining optimal coupling efficiency
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 configuration significantly improves light coupling efficiency by ensuring that more light is directed into the second optical element, reducing losses and maintaining high luminance, while minimizing the volume of the second optical element.
Implementation Method 1
the first optical element directs light by total internal reflection at its wall
Implementation Method 2
Light reflected from this reflector exits the optical element essentially perpendicular to the direction of light propagation in the light transmission area
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to an optical arrangement (1) with a first optical element (2), in the form of or comprising a light guide (19) that is bevelled obliquely with a bevel face (21), and a second optical element (3), wherein the first optical element (2) conducts light by total reflection at the wall (22) thereof, and has a light entry area (24), which is formed by the non-bevelled end face of the light guide (19), and has a light exit area (25), wherein the light exit area (25) is formed by a region of the wall (22) at the end of the light guide (19) at which the bevel face (21) is arranged. The second optical element (3) has a light entry aperture (30), which is arranged at the light exit area (25) of the first optical element (2) or opposite the light exit area (25) of the first optical element (2). The light entry area (25) of the first optical element (2) has a width (x) and the light entry aperture (30) of the second optical element (3) has a height (z) that are in the following relationship with one another: x/z ≤ 1.5 ⋅ [tan(90°-α/2)-tan(90°-(2 ⋅ [α/2+90°]-[180°-arcsin(1/n)]))]-1, where α denotes the deflecting angle of the light at the bevel face (21) and n denotes the refractive index of the material of the first optical element (2).