Replaceable Holographic Optical Element for Near-Eye Displays
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Solution Overview
Problem
Conventional head-worn displays face challenges in achieving a normal eyewear form factor without bulk, while maintaining see-through quality and field of view, requiring multiple lens configurations due to the laminated nature of holographic optical elements.
Innovation Solution
The use of pre-cut holographic optical elements (HOEs) that can be affixed to a lens blank using a reversible process, allowing for servicing and replacement, enabling the same lens inventory to be utilized across different frames and optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If holographic optical elements are laminated onto the entire lens surface, then the optical performance is maintained, but the device complexity and manufacturing cost increase due to requiring multiple lens configurations
Solution Approach 1:
The patent segments the HOE into a usable portion and a discarded portion, applying the optical element only to the specific area needed rather than laminating the entire lens surface. This reduces material waste and allows a single lens configuration to serve multiple purposes.
Solution Approach 2:
The patent applies alignment marks to the lens blank before attaching the HOE, enabling precise positioning during assembly. This preliminary action ensures proper optical alignment without requiring complex post-assembly adjustments or multiple configurations.
2Reliability
If custom lenses are manufactured for each frame and prescription, then the optical characteristics are optimized, but the manufacturing time and cost increase
Solution Approach 1:
Alignment marks are pre-applied to lens blanks in advance, allowing rapid and accurate attachment of HOEs during assembly. This eliminates the need for complex real-time alignment procedures and reduces manufacturing time while maintaining optical precision.
Solution Approach 2:
The alignment marks on the lens blank serve as self-aligning guides that direct the HOE placement automatically, reducing the need for sophisticated alignment equipment or skilled manual adjustment during manufacturing.
3Stability of the object's composition
If the HOE is permanently attached to the lens, then the optical alignment is stable, but the ease of repair and replacement decreases
Solution Approach 1:
The patent transitions from permanent to temporary attachment methods, allowing the HOE to be easily removed and replaced while maintaining stable alignment during use. The temporary adhesive provides sufficient stability for normal operation but enables simple replacement when needed.
Solution Approach 2:
The patent enables the HOE to be discarded (removed) and recovered (reused on another lens blank), transforming a previously permanent component into a replaceable one. This facilitates repair and reduces waste by allowing reuse of functional HOEs.
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 approach allows for a more versatile and serviceable head-worn display system that can be easily adapted to different frames and prescriptions, maintaining optimal performance and reducing the need for multiple lens configurations.
Implementation Method 1
an image may be reflected off a transparent projection surface to a user's eye
Implementation Method 2
projecting at least one alignment mark onto the lens; and attaching a holographic optical element (HOE) to the lens and aligning the HOE on the lens based on the at least one alignment mark
Data Source
AI summary
Disclosed herein is a lens for a wearable projection system. The lens includes a lens blank and a holographic optical element. The holographic optical element can be removably attached to the lens. The holographic optical element is aligned to a position on the lens surface based on temporary alignment marks projected onto the lens.