Compact AR Optical Device Using Micro-Mirror Array
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Solution Overview
Problem
Conventional augmented reality optical devices are bulky, inconvenient to wear, and costly due to complex configurations, with limited field of view and focus issues, requiring additional optical means and separate operations for focal length adjustments.
Innovation Solution
A compact optical device using multiple small-sized reflective units within a lens system that transmits real object light and reflects augmented reality image light, minimizing ghost images and light leakage, with a pinhole effect for infinite depth of field and adjustable focal length without additional optical means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical means such as prisms are used for augmented reality, then virtual image reflection and superposition is achieved, but device weight and volume become considerable
Solution Approach 1:
The patent divides the optical system into multiple small reflective units (micro-mirrors) arranged in an array rather than using a single large prism. Each micro-mirror is significantly smaller than the pupil diameter, allowing segmented reflection of virtual image light while maintaining overall functionality and reducing total material volume.
Solution Approach 2:
The patent transitions from conventional 2D surface reflection (prism) to 3D spatial light modulation using an array of micro-mirrors with controlled tilt angles. This dimensional approach allows light redirection through spatial arrangement rather than bulk material refraction, reducing device volume.
2Reliability
If conventional optical systems with prisms are used, then virtual image reflection is achieved, but manufacturing cost increases due to complex processes
Solution Approach 1:
The patent replaces complex mechanical optical systems (prisms, lenses, adjustable focal mechanisms) with a static micro-mirror array that uses geometric optics and controlled reflection angles. This substitution eliminates the need for complex manufacturing processes and mechanical adjustment components, simplifying production.
3Reliability
If a single small reflective unit smaller than pupil diameter is used, then depth of field increases and pinhole effect is achieved, but field of view becomes narrow
Solution Approach 1:
The patent segments the single small reflective unit into multiple micro-mirrors arranged in an array. Each micro-mirror maintains the pinhole effect for deep depth of field, while the collective array expands the total light-gathering area to widen the field of view without sacrificing the depth of field benefits of individual small units.
4Area of stationary object
If additional optical means such as collimators are added to increase field of view, then field of view expands, but device size, thickness, and volume increase
Solution Approach 1:
The patent merges the field of view expansion function directly into the micro-mirror array structure itself, rather than adding separate collimator components. The array geometry and tilt angles are designed to simultaneously achieve wide field of view and compact form factor, integrating multiple functions into a single compact unit.
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 provides a compact, comfortable, and cost-effective augmented reality device with increased field of view, reduced size and volume, and clear virtual images without the need for additional optical components or user-operated focal adjustments.
Implementation Method 1
an optical means 10 configured to transmit at least part of real object image light, which is image light output from a real object, therethrough toward a pupil of an eye of a user
Implementation Method 2
to reflect image light corresponding to an image for augmented reality, output from an image output unit 40, on an inner surface thereof
Implementation Method 3
a first reflective unit 20 disposed inside the optical means 10, and configured to reflect the image light corresponding to the image for augmented reality transferred from the inner surface of the optical means by reflection
Implementation Method 4
a second reflective unit 30 disposed inside the optical means 10, and configured to reflect the image light corresponding to the image for augmented reality, transferred from the first reflective unit 20, and transfer the image light corresponding to an image for augmented reality toward the pupil of an eye of a user
Implementation Method 5
the second reflective unit 30 has a size smaller than 8 mm... By forming the reflective unit 20 to be smaller than the average pupil of people as described above, the depth of field for light entering the pupil through the reflective unit 20 may be made almost infinite, i.e., considerably deep... This may be called as a kind of pinhole effect
Data Source
AI summary
Disclosed herein is a compact optical device for augmented reality. The compact optical device includes: an optical means configured to transmit at least part of image light, output from a real object, therethrough toward a pupil of an eye of a user and to reflect image light corresponding to an image for augmented reality, output from an image output unit, on an inner surface thereof and transfer the image light corresponding to an image for augmented reality to a first reflective unit; a first reflective unit disposed inside the optical means, and configured to reflect the image light corresponding to the image for augmented reality transferred from the inner surface of the optical means by reflection and transfer the image light corresponding to the image for augmented reality to a second reflective unit; and a second reflective unit disposed inside the optical means, and configured to reflect the image light corresponding to the image for augmented reality, transferred from the first reflective unit, and transfer the image light corresponding to an image for augmented reality toward the pupil of the eye of the user, thereby providing the image for augmented reality to the user; wherein the second reflective unit has a size smaller than 8 mm.