Virtual Image Display Device with Dynamic Focal Length Adjustment
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Solution Overview
Problem
Conventional augmented reality technologies fail to adjust the position of virtual images to match a user's gaze convergence distance, leading to eye fatigue due to mismatches between virtual and real-world scenes.
Innovation Solution
A virtual image display device comprising an image generator, a filter, a multipath optical element, and optical elements controlled by a processor to adjust focal lengths based on user gaze data, ensuring the virtual image is displayed at the correct convergence distance and orientation, while also correcting real-world scene distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional AR technology displays virtual images without adjusting focal length, then the device structure remains simple, but user eye fatigue increases due to mismatch between virtual image position and gaze convergence distance
Solution Approach 1:
The patent applies dynamics by making the focal length of optical elements adjustable based on user gaze data. The processor dynamically changes the focal length to match the user's gaze convergence distance, transforming a static optical system into a dynamic one that adapts to user needs, thereby improving comfort without excessive complexity
Solution Approach 2:
The patent implements parameter changes by modifying the focal length parameter of optical elements according to detected gaze convergence distance. This allows the virtual image position to be adjusted to match user comfort requirements, resolving the contradiction between simple structure and user comfort
2Reliability
If the virtual image is displayed at a fixed position, then the optical system is simple, but there is a mismatch between the virtual image and the real-world scene causing eye fatigue
Solution Approach 1:
The patent implements feedback by using gaze detection to obtain user convergence distance information, processing this data to determine appropriate focal length adjustments, and applying these adjustments to the optical elements. This closed-loop feedback system ensures accurate alignment between virtual and real-world scenes while managing control complexity through automated processing
Solution Approach 2:
The patent applies preliminary action by pre-calculating and adjusting the focal length based on predicted gaze convergence distance before the user experiences discomfort. The system proactively aligns the virtual image position with the real-world scene based on anticipated user behavior, preventing mismatch and eye fatigue
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 solution reduces eye fatigue by accurately aligning virtual images with the user's gaze, providing an undistorted real-world scene and enhancing the augmented reality experience by minimizing mismatches and distortions.
Implementation Method 1
a first optical element arranged on a first side of the multipath optical element and allowing the guided light in the first polarization state and real-world light to pass therethrough
Implementation Method 2
the first optical element diverges the light in the first polarization state and converges light in a second polarization state
Implementation Method 3
a second optical element arranged on a second side opposite to the first side of the multipath optical element and allowing the real-world light to pass therethrough
Implementation Method 4
the second optical element converges the light in the first polarization state and diverges the light in the second polarization state
Implementation Method 5
a filter transmitting light in a first polarization state in the output virtual image
Data Source
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AI summary
Provided is a virtual image display device including: an image generator outputting a virtual image; a filter transmitting light in a first polarization state in the output virtual image; a multipath optical element guiding the transmitted light in the first polarization state; a first optical element arranged on a first side of the multipath optical element and allowing the guided light in the first polarization state and real-world light to pass therethrough; a second optical element arranged on a second side opposite to the first side of the multipath optical element and allowing the real-world light to pass therethrough; and a processor controlling the image generator, the first optical element, and the second optical element.