Embedding Holographic Optical Elements in Eyeglass Lenses
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Solution Overview
Problem
Wearable heads-up displays lack aesthetically appealing designs while providing high-quality images without obstructing the external environment, and existing methods for embedding holographic optical elements in eyeglass lenses often damage these elements due to high temperatures and harsh chemicals.
Innovation Solution
A method of embedding a holographic optical element in an eyeglass lens using low-temperature optically clear adhesives, which are cured below the maximum stable temperature of the element, along with a protective layer to prevent damage, and incorporating high-temperature coatings for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional embedding methods using high-temperature processes are used, then the eyeglass lens achieves durability and structural integrity, but the holographic optical element is damaged due to temperature exceeding its stable range
Solution Approach 1:
The lens manufacturing process is divided into distinct temperature zones: high-temperature processes (melting, forming, coating) are completed before HOE insertion, followed by low-temperature assembly (below 100°C) for embedding the HOE. This segmentation allows each component to be processed at its optimal temperature range without damage.
Solution Approach 2:
All high-temperature lens manufacturing steps (melting, forming, coating application and curing) are performed in advance before the HOE is inserted. The lens is prepared in its complete form first, then the HOE is embedded at low temperature, eliminating the need to expose the HOE to high temperatures during lens fabrication.
2Shape
If the holographic optical element is embedded in the lens, then the wearable display achieves aesthetic appeal and compact design, but the element is vulnerable to damage from mechanical forces and high temperatures during manufacturing
Solution Approach 1:
A protective layer is applied to the HOE before embedding it in the lens. This protective layer acts as a cushion against mechanical forces and thermal stress during subsequent manufacturing processes, preventing damage to the fragile fringes while allowing the lens to be formed and coated.
Solution Approach 2:
The protective layer serves as an intermediary between the HOE and the harsh manufacturing environment. It mediates the interaction by absorbing mechanical stresses and thermal expansion forces, protecting the HOE from direct exposure to damaging conditions while still allowing the HOE to function optically.
3Strength
If high-temperature coatings are applied to the lens, then scratch resistance and UV blocking are improved, but the holographic optical element suffers irreversible damage from thermal exposure
Solution Approach 1:
The coating process is segmented into two stages: first, a preliminary coating is applied at low temperature to protect the HOE; second, the final high-temperature coating is applied after the HOE is securely embedded and protected, ensuring the HOE never暴露在 temperatures above its stable range while still achieving durable surface coating.
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 allows for the creation of aesthetically pleasing wearable heads-up displays with embedded holographic optical elements that maintain optical performance and durability, preventing damage from high-temperature processes and harsh chemicals.
Implementation Method 1
a first low-temperature optically clear adhesive ("LT-OCA") layer disposed between the HOE and the eye-side lens; and a second LT-OCA layer disposed between the HOE and the world-side lens portion
Implementation Method 2
HOEs are generally fabricated using light-reactive substances, which when exposed to light under the correct conditions form a series of very small and carefully spaced fringes; it is the combined set of fringes that form the HOE. Non-exclusive examples of light reactive substances are silver-halide emulsions and photopolymers
Implementation Method 3
A hologram or holographic optical element (HOE) is an optical element that comprises a series of ridges or fringes that form an optical element by diffracting light
Implementation Method 4
The world-side lens portion may include a world-side surface, and the world-side lens portion may further include a coating layer disposed on the world-side surface of the world-side lens portion, the coating layer including a high-temperature coating
Data Source
AI summary
Systems, devices, and methods for embedding a HOE in an eyeglass lens are described. A method of embedding a HOE in an eyeglass lens includes forming a world-side portion of the eyeglass lens, forming an eye-side portion of the eyeglass lens, physically coupling the eye-side portion of the eyeglass lens to the HOE with a low-temperature optically clear adhesive (“LT-OCA”), and physically coupling the world-side portion of the eyeglass lens to the HOE with LT-OCA. Forming the lens portions may include high-temperature processes, and the HOE may not be damaged by the high-temperature processes since the high-temperature processes may be performed on the lens portions prior to coupling the lens portions to the HOE.