AR Optical Means with Non-Parallel Surfaces for Close Focal Length
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Solution Overview
Problem
Conventional optical devices for augmented reality struggle to provide clear images at focal lengths other than infinity, leading to distortion or breakage when the focal length changes, due to incomplete optical path length matching and the need for additional components like concave and convex lenses.
Innovation Solution
An optical device with an optical means having non-parallel first and second surfaces, each with an inclination angle (θ) set between 0.015° to 4.6°, to ensure proper image light transmission and reflection, allowing for clear augmented reality images at close focal lengths without distortion or breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical systems use parallel light paths for infinite focal length, then the depth of field is increased, but the ability to provide clear images at close focal lengths is lost
Solution Approach 1:
The patent applies asymmetry by making the first and second surfaces of the optical means non-parallel to each other, forming a specific angle (α) between them. This asymmetric configuration allows the optical system to handle both parallel light paths (for infinite focal length) and divergent light paths (for close focal lengths) effectively, resolving the contradiction between deep depth of field and close focal length capability
Solution Approach 2:
The patent changes the geometric parameter of the optical means by setting a specific angle (α) between the first and second surfaces. This parameter change enables the optical system to maintain proper optical path length matching across different focal lengths, allowing clear image formation from close distances while preserving the depth of field benefits
2Adaptability or versatility
If additional optical components (concave and convex lenses) are added to achieve close focal length, then the focal length adaptability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of multiple optical components into a single optical means with non-parallel surfaces. By integrating the light path adjustment functionality directly into the optical means structure, the system achieves close focal length capability without requiring separate concave and convex lenses, thereby reducing device complexity
Solution Approach 2:
The optical means with non-parallel surfaces serves multiple functions: it transmits light from real objects, reflects image light from the image output unit, and adjusts optical path lengths for different focal lengths. This multi-functional design eliminates the need for additional specialized components, simplifying the overall device structure
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 optical device effectively provides clear augmented reality images at close focal lengths by optimizing the inclination angle between surfaces, ensuring proper image alignment and reducing the need for additional components, thus enhancing user experience and device simplicity.
Implementation Method 1
an optical means (10) configured to transmit at least part of image light, output from a real object, therethrough toward a pupil (40) of an eye of a user
Implementation Method 2
transfer image light corresponding to an image for augmented reality, output from an image output unit (30), to at least one optical element (20) by reflecting the image light from the inner surface thereof at least once
Data Source
AI summary
The present invention provides an optical device for augmented reality, the optical device including: an optical means configured to transmit at least part of image light therethrough toward the pupil of an eye of a user, and to transfer image light corresponding to an image for augmented reality to at least one optical element by reflecting the image light from the inner surface thereof at least once; and the optical element disposed inside the optical means, and configured to provide the image for augmented reality to the user by transferring the image light, corresponding to the image for augmented reality transmitted through the optical means, toward the pupil of the user; wherein the optical means includes a first surface and a second surface, and the first surface and the second surface have an inclination angle with respect to each other so as not to be parallel to each other.