Virtual Image Display Device with Light Branching Layer
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Solution Overview
Problem
Existing head-mounted displays with virtual image technology require complex structures for pupil detection and image light beam alignment, leading to increased complexity and difficulty in achieving a simple and effective virtual image display.
Innovation Solution
A virtual image display device with a simplified structure that uses an optical element comprising a first and second light guide section connected by a light branching layer, allowing the picture light beam to be partially reflected and transmitted, and a light deflection section with a hologram for easy adjustment of the light beam direction to the observer's eyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a head-mounted display uses a detection device and position changing mechanism to match the picture light beam with eye movement, then the visual recognition is improved, but the device complexity increases
Solution Approach 1:
The patent removes the complex detection device and position changing mechanism from the system. Instead of actively tracking eye movement, the invention extracts only the essential function of directing light to the eye by using a fixed optical element with a specific exit pupil position, thereby simplifying the overall structure while maintaining visual recognition capability.
Solution Approach 2:
The optical element is designed to inherently guide the picture light beam to the correct position without requiring external detection or adjustment mechanisms. The exit pupil is positioned within the visual field of the user's eye, allowing the system to self-align and eliminate the need for complex control systems.
2Use of energy by moving object
If the picture light beam cross-sectional area is enlarged, then the light efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent enlarges the picture light beam cross-sectional area by utilizing the spatial dimension within the optical element. The light beam propagates through the optical element and emerges with an expanded cross-section, effectively increasing light efficiency without adding complex mechanical or electronic components.
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 enables a simple and effective magnification of the picture light beam, improving light efficiency and preventing color aberration, while allowing for easy adjustment of the light beam to enhance visual recognition for the observer.
Implementation Method 1
a first light branching layer disposed between the first light guide section and the second light guide section, and adapted to partially reflect the picture light beam emitted from the image generation section, and partially transmit the picture light beam
Implementation Method 2
an exit surface adapted to emit a picture light beam obtained by enlarging a cross-sectional area of the picture light beam input to the plane of incidence
Data Source
AI summary
A virtual image display device including an image generator for generating a picture light beam modulated based on a video signal, and an optical element including a plane of incidence to which the picture light beam emitted from the image generator is input, and an exit surface emitting the picture light beam after a cross-sectional area of the picture light beam input to the plane of incidence has been enlarged. The optical element includes a first light guide and a second light guide connecting the plane of incidence and the exit surface and guiding the picture light beam. A first light branching layer is disposed between the first and second light guides, and partially reflects and partially transmits the picture light beam. The picture light beam emitted from the image generator obliquely enters the first light branching layer.