Partial Beam Splitter Phase Control for AR Waveguides
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Solution Overview
Problem
Conventional reflective augmented reality waveguides suffer from low image contrast and reduced sharpness due to suboptimal image quality, which is not effectively addressed by existing technologies.
Innovation Solution
A partial beam splitter is designed with a substrate and coatings that control the phase difference of light beams within specific wavelength ranges (450 nm to 650 nm) to improve image quality, featuring a substrate with coatings on its main surfaces, ensuring a phase difference of less than or equal to 30° for light beams incident at a 32° angle, enhancing image clarity and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional partial beam splitters are used in reflective augmented reality waveguides, then the device structure is simple, but the image quality is poor with low contrast and reduced sharpness
Solution Approach 1:
The patent applies parameter changes by precisely controlling the phase difference parameter of the light beam passing through the partial beam splitter. By adjusting the coating thickness and material properties to achieve a specific phase difference range (0° to 30°), the image quality parameters (contrast and sharpness) are improved without fundamentally changing the device structure
Solution Approach 2:
The patent uses composite materials by combining a substrate with specific coating layers having different refractive indices and thicknesses. This composite structure enables precise control over the phase difference while maintaining the simplicity of the overall beam splitter design
2Manufacturing precision
If the phase difference is not controlled, then the manufacturing process is simpler, but the light beam propagation paths create critical differences that reduce image quality
Solution Approach 1:
The patent implements parameter changes by establishing a specific phase difference range (0° to 30°) as a manufacturing target. This parameter specification guides the coating thickness and material selection processes, enabling precise phase control while maintaining manufacturability through standard optical deposition techniques
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 controlled phase difference significantly improves image quality in reflective augmented reality waveguides by minimizing critical differences in light beam propagation paths, resulting in high-quality images for users, while maintaining a neutral appearance when viewed by others.
Implementation Method 1
for a specific light beam having a specific wavelength within a range of 450 nm and 650 nm which is incident on the partial beam splitter along a second direction with an angle of 32° enclosed between a vector pointing in the first direction and a vector pointing in the second direction, the specific light beam after transmitting through the partial beam splitter has a phase having a phase difference of an absolute value of smaller than or equal to 30°
Data Source
AI summary
A partial beam splitter includes a substrate including a substrate material; and a coating arranged on at least one main surface of the substrate. Along a first direction which is parallel to a normal vector of the main surface, the substrate and all coatings having a total thickness. For a specific light beam having a specific wavelength within a range of 450 nm and 650 nm which is incident on the partial beam splitter along a second direction with an angle of 32° enclosed between a vector pointing in the first direction and a vector pointing in the second direction, the specific light beam after transmitting through the partial beam splitter has a phase having a phase difference of an absolute value of smaller than or equal to 30° compared to the case in which, under otherwise identical conditions, the partial beam splitter is replaced by a similar reference substrate.