Geometric Phase Lens Optical Device for Stray Light Management
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Solution Overview
Problem
Virtual reality and augmented reality electronic devices face challenges with stray light due to optical anisotropy in resin lenses, leading to image degradation and reduced display quality, and require thin, lightweight, and high-resolution optics with a wide viewing angle.
Innovation Solution
A thin optical device comprising a half mirror, a geometric phase lens, a retardation plate, and a reflective polarizing plate, which uses negative and positive refractive powers to manage stray light and enhance image focus, while maintaining a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a resin lens is used to reduce weight, then the device becomes lightweight, but optical anisotropy causes birefringence that disrupts polarization state and generates stray light
Solution Approach 1:
A circular polarizing plate is introduced as an intermediary component between the resin lens and the display panel. This plate compensates for the polarization disruption caused by the resin lens's birefringence, restoring the correct polarization state and eliminating stray light generation while allowing the lightweight resin lens to be used
2Reliability
If a glass lens is used to maintain optical characteristics, then polarization state is preserved, but the device becomes heavier
Solution Approach 1:
The invention changes the material parameter from glass to resin for the lens, achieving weight reduction. The optical performance is maintained not by the material itself but by introducing a circular polarizing plate that compensates for the resin's birefringence, effectively decoupling material selection from optical performance requirements
3Manufacturing precision
If the optical path length is increased to improve image quality, then the device becomes thicker
Solution Approach 1:
The invention addresses the optical path length requirement by utilizing the overlapping region in the vertical dimension where multiple optical components (display panel, circular polarizing plate, resin lens, and eye) are stacked. This allows sufficient optical path length for image quality while keeping the horizontal footprint compact and the overall device thin
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 stray light, improves display quality, and increases the viewing angle, resulting in a more immersive and realistic user experience with reduced power consumption.
Implementation Method 1
A thin optical device includes an optical system that ensures an optical path length by repeating transmission and reflection of polarized light in the optical device
Implementation Method 2
The first lens has negative refractive power with respect to circularly polarized light that passes through the half mirror and enters the first lens
Implementation Method 3
The first lens is a geometric phase lens. The first lens has negative refractive power with respect to circularly polarized light
Implementation Method 4
a reflective polarizing plate, and a second lens. The half mirror, the first lens, the retardation plate, the reflective polarizing plate, and the second lens are placed in this order to have an overlapping region
Data Source
AI summary
An optical device with less influence of stray light is provided. The optical device is thin and includes a half mirror, a first lens, a retardation plate, a reflective polarizing plate, and a second lens. In the optical device, a geometric phase lens which has negative and positive refractive power is used as the first lens, whereby images can be focused after magnified optically. Thus, the optical device can have a wide viewing angle. In the case where stray light occurs due to birefringence of an optical material, negative refractive power of the first lens can prevent the stray light from being focused on the eye direction. Accordingly, image degradation recognized due to stray light can be prevented.