AR Optical Device Refractive Space for Compact FOV
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Solution Overview
Problem
Conventional optical devices for augmented reality face challenges in adjusting the optical system performance, providing a clear virtual image across varying focal lengths, and maintaining a compact form factor due to limitations in manufacturing complexity, cost, and image sharpness, especially with half mirror-type and holographic/diffractive optical combiners.
Innovation Solution
An optical device with a refractive space formed inside the optical means, incorporating a first optical element and a second optical element, where virtual image light is refracted and reflected through the refractive space to adjust focal length and improve image clarity, using a combination of refractive, diffractive, or reflective elements to enhance the optical system's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If half mirror-type combiners are used to provide wide FOV, then the field of view is improved, but the volume and weight increase
Solution Approach 1:
The patent merges multiple half-mirrors into a single integrated optical element called a 'light guide optical element' that combines the functions of multiple mirrors and waveguides. This integration reduces the overall volume and weight while maintaining the wide field of view capability by optimizing the light path through the integrated structure.
Solution Approach 2:
The patent embeds multiple small half-mirrors inside a waveguide structure, creating a nested configuration where the optical elements are contained within a compact housing. This nesting approach allows the system to maintain wide FOV while reducing external dimensions and weight.
2Weight of stationary object
If Light-guide Optical Element with multiple half-mirrors is used to reduce volume and weight, then the volume and weight are reduced, but the manufacturing process becomes complicated and luminous uniformity is lowered
Solution Approach 1:
By integrating multiple half-mirrors and waveguide functions into a single molded optical element, the patent simplifies the manufacturing process compared to assembling separate components. The integrated structure can be manufactured using precision molding techniques, reducing assembly complexity while maintaining weight reduction benefits.
3Manufacturing precision
If HOE/DOE-type combiners are used to achieve precise optical control, then the optical performance is improved, but the manufacturing cost increases and yield decreases
Solution Approach 1:
The patent uses refractive index variations and geometric parameter optimization in the light guide optical element to achieve precise optical control without requiring complex holographic or diffractive structures. By adjusting the refractive index profile and geometric dimensions during manufacturing, the system achieves comparable optical performance with simpler, more cost-effective manufacturing processes.
4Adaptability or versatility
If conventional optical combiners are used, then the basic AR function is achieved, but the virtual image is out of focus when user changes focal length
Solution Approach 1:
The patent incorporates a dynamic optical element that can adjust its focal length in response to user needs. This dynamic capability allows the system to maintain focus across varying distances while the user interacts with both virtual and real-world objects, providing adaptability without sacrificing image quality.
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 allows for precise adjustment of the optical system performance, maintaining image clarity across focal length changes while reducing device size and weight, by using a refractive space and optical elements to collimate virtual image light effectively.
Implementation Method 1
a refractive space formed inside the optical means; the virtual image light output from the image output unit enters the first optical element through the second surface of the refractive space, is reflected by the first optical element and then output through the second surface of the refractive space
Implementation Method 2
is reflected by the first optical element and then output through the second surface of the refractive space
Data Source
AI summary
The present invention provides an optical device for augmented reality having a refractive space, the optical device including: a first optical element configured to transfer virtual image light to a second optical element; the second optical element configured to transfer the virtual image light toward the pupil of an eye of a user; an optical means configured such that the first optical element and the second optical element are embedded therein; and a refractive space formed inside the optical means; wherein the refractive space has a first surface and a second surface; and wherein the virtual image light output from the image output unit enters the first optical element through the second surface of the refractive space, is reflected by the first optical element and then output through the second surface of the refractive space, and is then transferred to the second optical element.