Multilayer Diffractive Optical Element Tapered Peripheral Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer diffractive optical elements experience resin peeling due to stress from cure shrinkage and decreased bonding strength over time, especially in high-temperature environments, as existing manufacturing methods do not effectively disperse stress at the interface between resin layers and glass substrates.
Innovation Solution
The design incorporates a first resin layer with a specific peripheral shape, including a region with a thickness greater than the grating height and a second region with a tapered shape, which disperses stress and prevents resin peeling by ensuring the resin layer thickness varies continuously, thereby maintaining high diffraction efficiency and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diffractive optical element with a protrusion at the periphery of the diffraction grating pattern is manufactured, then the grating pattern can be formed with defined boundaries, but large stress remains at the step portion due to cure shrinkage and resin peeling occurs after extended use in high-temperature environments
Solution Approach 1:
The invention changes the geometric parameters of the diffractive optical element by introducing a tapered portion that gradually reduces the protrusion height from the periphery toward the optically effective region. This continuous parameter change eliminates abrupt steps, allowing stress to be dispersed throughout the tapered structure rather than concentrated at a single interface, thereby preventing resin peeling while maintaining manufacturing precision
Solution Approach 2:
The invention applies a curved/tapered profile to the peripheral portion of the diffractive optical element instead of an abrupt step. The tapered shape creates a smooth transition zone that curves gradually from the protrusion to the base level, which effectively disperses the stress generated during resin curing and prevents concentration at sharp corners or steps
2Reliability
If a tapered shape is applied to the multilayer diffractive optical element to disperse stress, then resin peeling is prevented, but a broad area needs to be secured outside the optically effective region which increases the size of the optical element
Solution Approach 1:
The invention applies the tapered shape only to the peripheral portion of the diffractive optical element, specifically where the protrusion exists at the boundaries of the diffraction grating pattern. The optically effective central region maintains its original design characteristics. This localized application of the tapered profile disperses stress at the critical interface regions without adding unnecessary material or increasing the overall size of the optical element
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 effectively suppresses resin peeling and maintains high diffraction efficiency even after extended use in high-temperature environments, ensuring the durability and performance of the multilayer diffractive optical elements.
Implementation Method 1
a first region 6 that has a thickness greater than an average grating height hd of the diffraction grating pattern... a second region 7 that has a smaller thickness than the average thickness h1 of the first region 6... the stress that remains when the adhesive is cured is dispersed so as to prevent the peeling from occurring
Implementation Method 2
a first resin layer 4 having a first diffraction grating pattern... a second resin layer 5 having a second diffraction grating pattern... maintaining high diffraction efficiency
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A multilayer diffractive optical element (1) includes a first substrate (2), a second substrate (3), a first resin layer (4) having a first diffraction grating pattern and interposed between the first substrate and the second substrate, and a second resin layer (5) having a second diffraction grating pattern and interposed between the first substrate and the second substrate. The first resin layer includes a first region (6) provided at a peripheral portion adjacent to a portion of the first diffraction grating pattern. The first resin layer includes a second region (7) provided at a peripheral portion adjacent to the first region.