Embedded Transmissive Diffractive Optics With Anti-Reflective Phase Layers
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Solution Overview
Problem
Current diffractive optical lenses are limited in terms of phase quantizations and anti-reflective properties, and are not readily compatible with wafer-to-wafer bonding techniques due to their single-material construction and fixed refractive index, which affects their ability to apply coatings like anti-reflective coatings.
Innovation Solution
The development of transmissive diffractive optical elements with multiple phase shift layers, including a substrate and immersion material layers, which incorporate anti-reflective phase shift regions to transmit light with varying phase shifts, allowing for destructive interference of reflections and enhanced design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a diffractive optical lens is made of a single material with fixed refractive index, then the lens structure is simple and manufacturing is easier, but the phase quantizations are limited and anti-reflective properties are insufficient
Solution Approach 1:
The lens is segmented into multiple phase shift layers (first phase shift layer and second phase shift layer) with different materials and refractive indices. Each layer contributes differently to the phase modulation of transmitted light, enabling multiple distinct phase quantizations (e.g., 0, π/2, π, 3π/2) that cannot be achieved with a single material.
Solution Approach 2:
The lens uses composite materials consisting of multiple immiscible materials (e.g., polymer and glass) with different refractive indices arranged in specific patterns within the phase shift layers. This composite structure provides both the structural integrity needed for manufacturing and the optical properties required for enhanced phase quantizations and anti-reflective characteristics.
2Adaptability or versatility
If diffractive microstructures are made with various heights and widths to customize function, then the optical performance is improved, but the external surface becomes non-planar
Solution Approach 1:
The diffractive microstructures are nested within the phase shift layers that are themselves embedded in the immersion lens body. The microstructures are positioned below the external surface, allowing the top surface to remain planar while the internal structures provide the necessary optical modulation through varying heights and widths.
Solution Approach 2:
The patent transitions from surface-level diffractive structures to subsurface embedded structures. By moving the diffractive microstructures into the bulk material and using multiple phase shift layers with different refractive indices, the optical functionality is achieved through the third dimension (depth) rather than surface topology, maintaining a planar external surface.
3Ease of manufacture
If the top surface is made planar to enable wafer-to-wafer bonding and coating application, then manufacturing compatibility is improved, but the ability to modulate light through diffractive structures is reduced
Solution Approach 1:
The diffractive microstructures are nested within the phase shift layers that are embedded in the immersion lens body. The microstructures are positioned below the external surface, allowing the top surface to remain planar for wafer bonding and coating while the internal structures provide the necessary optical modulation.
Solution Approach 2:
The phase shift layers act as intermediaries between the planar external surface and the diffractive microstructures. These layers with different refractive indices enable light to interact with the embedded microstructures while the external surface maintains its planarity for manufacturing processes.
4Object-affected harmful factors
If anti-reflective coating is applied to reduce reflections, then the anti-reflective properties are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The lens structure itself provides anti-reflective functionality through the phase shift layers with different refractive indices. The multi-layer structure creates destructive interference of reflected light at the interfaces, eliminating the need for separate anti-reflective coatings and simplifying the manufacturing process.
Solution Approach 2:
The use of composite materials with different refractive indices in the phase shift layers creates inherent anti-reflective properties. The refractive index gradient and multiple interfaces cause reflected light waves to interfere destructively, reducing reflections without requiring additional coating materials or processes.
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 lenses with multiple phase quantizations and improved anti-reflective properties, enabling compatibility with wafer-to-wafer bonding and reducing reflections, thus enhancing the functionality and application of diffractive optical lenses.
Implementation Method 1
Diffractive optical lenses, sometimes referred to as diffractive optical elements, are commonly used to modulate light by diffraction
Implementation Method 2
the lenses may be formed so that reflections at one or more interfaces between material layers will destructively interfere, thereby reducing or eliminating reflections
Implementation Method 3
A function of the diffractive microstructures of the diffractive optical lens is dependent on a refractive index of a material used to form the microstructures and a refractive index of an environment in which the microstructure exists
Data Source
AI summary
Various embodiments provide optical lenses that include phase shift layers that transmit incident light with four or more distinct phase quantizations. In one embodiment, a lens includes a substrate, a first immersion material layer on the substrate, and a plurality of anti-reflective phase shift layers on the first immersion material layer. The phase shift layers define a first anti-reflective phase shift region that transmits received light without a phase shift, a second anti-reflective phase shift region configured to transmit the received light with a first phase shift, a third anti-reflective phase shift region configured to transmit the received light with a second phase shift, and a fourth anti-reflective phase shift region configured to transmit the received light with a third phase shift. The first, second, and third phase shifts are different from one another.