See-Through Display Prism Coupling for Noise Light Reduction
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Solution Overview
Problem
Head-mounted displays suffer from image noise and foreground noise that reduce visibility in augmented reality displays by allowing noise light to reach the user's field of view.
Innovation Solution
A see-through display apparatus with a noise reduction prism and optical coupler that utilizes inclined surfaces to perform path conversion, ensuring only effective light is incident on the optical coupler while noise light is not, combined with polarizers and beam splitters to further reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional optical path is used in AR display, then the structure is simple, but noise light reaches the user's field of view reducing visibility
Solution Approach 1:
The patent extracts and removes noise light from the optical path by introducing a noise reduction prism that selectively eliminates unwanted light angles before they reach the field of view, while maintaining the core optical coupling function
Solution Approach 2:
The noise reduction prism acts as an intermediary element between the display device and the field of view, mediating the optical path by allowing effective light to pass through while blocking noise light through total internal reflection
2Illumination intensity
If the angle range for effective light is widened, then more light reaches the field of view improving brightness, but more noise light also reaches the field of view
Solution Approach 1:
The noise reduction prism creates different optical treatment zones within the same optical path - angles within the predetermined range experience transmission while angles outside this range experience total internal reflection, achieving local quality differentiation based on incident angle
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 apparatus provides a high-quality augmented reality display by minimizing noise light in the observer's field of view, enhancing visibility and preventing unwanted light leakage.
Implementation Method 1
including a plurality of inclined surfaces configured to perform path conversion so that, among light of the first image, effective light of a predetermined angle range is incident on the optical coupler and noise light of a remaining angle range remaining from the predetermined angle range is not incident on the optical coupler. The angles between the inclined surfaces are based on a critical angle for total reflection that is determined by the predetermined angle range of the effective light and a refractive index of the noise reduction prism.
Implementation Method 2
an optical coupler configured to obtain a combined image by combining a first image from the display device with a second image from a path different from a path of the first image
Data Source
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AI summary
A see-through display apparatus includes a display device, and an optical coupler configured to obtain a combined image by combining a first image from the display device with a second image from a path different from a path of the first image, and emit the obtained combined image. The optical coupler includes a first surface on which the first image is incident, a second surface on which the second image is incident, and an exit surface through which the combined image is emitted. A noise reduction prism is disposed between the display device and the optical coupler, and includes inclined surfaces configured to perform path conversion so that, among light of the first image, effective light of a predetermined angle range is incident on the optical coupler and noise light of a remaining angle range remaining from the predetermined angle range is not incident on the optical coupler.