Light Guide Mirror Angle Optimization for See-Through Display Uniformity
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Solution Overview
Problem
Display unevenness occurs in see-through type image display apparatuses due to the presence of multiple mirrors or reflection surfaces, causing visual recognition issues for the observer.
Innovation Solution
A display apparatus with a light guide that includes an incident portion and an emission portion with mirrors inclined relative to the total reflection surface, where the mirror angle is set to satisfy specific expressions to minimize the error in the number of mirrors through which image light is transmitted, reducing display unevenness and preventing double images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple mirrors or reflection surfaces are positioned in front of the observer's eyes to guide light, then the image light can be directed toward the eyes, but display unevenness is visually recognized
Solution Approach 1:
The patent extracts and removes the problematic mirrors or reflection surfaces from the optical path. By eliminating these reflective elements that cause display unevenness, the invention achieves uniform image display without the visual artifacts caused by multiple reflections, while still directing image light toward the observer's eyes through alternative means.
2Illumination intensity
If mirrors are used to reflect image light toward the eyes, then the image can be viewed, but image light is lost through reflection
Solution Approach 1:
The patent converts the harmful effect of light loss through reflection into a beneficial outcome by using a different optical mechanism. Instead of relying on reflective mirrors that inherently lose light, the invention employs a design that transmits image light more efficiently, converting the problem of reflection-based light loss into a solution that minimizes energy loss while still achieving the desired light direction toward the observer's eyes.
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 reduces display unevenness and image light loss, providing a clear and bright image by optimizing the mirror angle and light guide configuration, ensuring a consistent image across all angles of view.
Implementation Method 1
The light guide has a total reflection surface that guides the image light
Implementation Method 2
an emission portion including a plurality of mirrors that are provided parallel to each other inside the light guide with an interval therebetween, and cause a part of the image light guided inside the light guide to be reflected
Data Source
AI summary
A display apparatus includes an image forming device and a light guide. The light guide includes an incident portion and an emission portion including a plurality of mirrors. In the light guide, the total reflection surface is disposed to be inclined with respect to a virtual plane perpendicular to a visual axis, and the mirrors are disposed to be inclined with respect to the total reflection surface. The mirror angle is set such that the light guide angle, the mirror angle, the light angle, the limit incidence angle, and the refractive index of the light guide satisfy the predetermined relationship.