Light Guide Device Asymmetric Partial Reflection Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display apparatuses with light guide devices suffer from image quality degradation due to gaps and overlaps between partial reflection surfaces, leading to streaks and brightness variations when viewed by an observer.
Innovation Solution
A light guide device configuration where partial reflection surfaces are inclined such that their intervals are widened from one end to the other, and the device is positioned with the further end away from the observer, minimizing gaps and overlaps, and using dielectric multilayer films and reflective metal layers for optimized reflectance and transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plurality of obliquely-inclined half mirrors are provided in parallel at equal intervals between two planes, then the light guide device can guide image light beams from one end to another end, but gaps and overlap portions occur between adjacent partial reflection surfaces causing streaks and brightness variations
Solution Approach 1:
The patent applies asymmetry by varying the intervals between adjacent partial reflection surfaces along the light propagation direction. Instead of equal intervals, the intervals are designed to be non-uniform, with smaller intervals at positions where overlap would occur and larger intervals where gaps would form. This asymmetric arrangement compensates for the optical path differences and eliminates streaks and brightness variations, improving image uniformity.
Solution Approach 2:
The patent implements local quality by adjusting the interval between partial reflection surfaces based on their specific positions. Each pair of adjacent partial reflection surfaces has a customized interval tailored to prevent gaps or overlaps at that location. This localized adjustment ensures that each region of the light guide device maintains optimal performance, preventing streaks and brightness variations throughout the entire image area.
2Manufacturing precision
If the half mirrors are disposed at a variable pitch, then the overlap and gap issues may be partially addressed, but streaks cannot be completely prevented
Solution Approach 1:
The patent applies parameter changes by systematically varying the interval parameter between partial reflection surfaces. The interval is changed as a function of position along the light propagation direction, with specific mathematical relationships defined to achieve the desired optical effect. This controlled parameter variation allows precise positioning accuracy to eliminate streaks while maintaining manageable device complexity through systematic design rules.
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 suppresses image quality degradation by reducing streaks and brightness variations, allowing for a high-quality, uniform image recognition by the observer.
Implementation Method 1
a plurality of partial reflection surfaces which are disposed along the first direction between the first surface and the second surface and are inclined at the same angle from a normal direction with respect to the second surface toward the one end side
Data Source
AI summary
A light guide system includes a transparent light guide portion that guides light beams incident from one end side to a light-emitting portion. The light guide portion includes a plurality of partial reflection surfaces that are disposed between a first surface and a second surface which are parallel to each other and are inclined at the same angle such that a first end portion is positioned closer to the one end side than a second end portion is. Intervals between the partial reflection surfaces in a first direction are widened from the one end side toward another end side. In a state where the light guide portion is disposed in front of an eye of an observer, the light guide portion is inclined such that the another end side is further away from a face of the observer than the one end side is.