Compact AR Waveguide Optics for Ghost-Image Blocking
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Solution Overview
Problem
Conventional augmented reality optical devices are bulky, costly, and suffer from ghost images due to stray light, limiting their field of view and optical efficiency.
Innovation Solution
A compact optical device with internal reflective units, including a first reflective means to block stray light and a second reflective means with multiple units to enhance image clarity and field of view, utilizing total internal reflection and precise arrangement of reflective surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical systems with prisms are used for augmented reality, then virtual image reflection and superposition is achieved, but device size, weight, and volume become considerable
Solution Approach 1:
The patent divides the optical system into multiple functional components: a waveguide for light transmission, reflective units for virtual image reflection, and blocking units for stray light management. This segmentation allows each component to be optimized independently, reducing overall device weight while maintaining AR functionality.
Solution Approach 2:
The reflective units and blocking units are embedded within the waveguide structure, creating a nested configuration. This integration eliminates the need for separate external optical components, significantly reducing device volume and weight while preserving the virtual image superposition capability.
2Reliability
If conventional optical systems with prisms are used for augmented reality, then virtual image reflection is achieved, but manufacturing cost increases due to complicated processes
Solution Approach 1:
The patent merges the reflective function and the blocking function into a single integrated waveguide structure. By combining multiple optical functions into one component, the manufacturing process is simplified compared to assembling multiple separate prisms and optical elements, reducing both complexity and cost.
Solution Approach 2:
The waveguide structure serves multiple functions simultaneously: transmitting real world light, reflecting virtual images, and blocking stray light. This multi-functionality reduces the number of separate components needed, simplifying manufacturing while maintaining comprehensive optical performance.
3Area of stationary object
If reflective unit size is increased to improve field of view, then more light is captured, but ghost images increase due to stray light reflection
Solution Approach 1:
The patent introduces blocking units as intermediary elements positioned between the reflective units and the user's eye. These blocking units intercept stray light that would otherwise create ghost images, allowing the reflective units to maintain larger sizes for improved field of view without suffering from ghost image degradation.
4Reliability
If focal length adjustment mechanism is added to maintain focus when user changes focal length, then image focus is maintained, but device complexity and operation requirements increase
Solution Approach 1:
The optical system is designed to naturally maintain focus across different viewing distances through the specific geometric arrangement and optical properties of the waveguide and reflective units. This self-focusing capability eliminates the need for active focal length adjustment mechanisms, reducing device complexity while maintaining reliable image focus.
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 device significantly reduces size, weight, and volume while effectively blocking ghost images, providing a clear and wide field of view with improved optical efficiency.
Implementation Method 1
the optical means 10 also functions to transmit the augmented reality image light, reflected by the reflective unit 30, therethrough to the pupil
Implementation Method 2
The reflective unit 30 reflects image light corresponding to an image for augmented reality, output from the image output unit 40, toward the pupil of a user
Data Source
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AI summary
The present invention provides a compact optical device for augmented reality having a ghost image blocking function and a wide field of view. The compact optical device includes: an optical means configured to transmit at least part of real object image light therethrough toward the pupil of an eye of a user; a first reflective means disposed inside the optical means and configured to transfer the augmented reality image light output from an image output unit to a second reflective means; and a second reflective means disposed inside the optical means and to reflect the augmented reality image light, transferred from the first reflective means, and transfer the augmented reality image light to the pupil of the eye of the user, thereby providing an image for augmented reality to the user.