Optical Element Adhesive Resin for Thermal Peeling Control
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Solution Overview
Problem
Existing composite optical elements with different material components suffer from low adhesion force, leading to shape changes, cracks, and peeling due to temperature variations, with insufficient suppression of peeling and surface shape changes in temperature-changing environments.
Innovation Solution
An optical element design featuring a convex first lens, a concave second lens, and an adhesive resin with specific elastic modulus ratios and thickness relationships, where the thickness of the optical resin center is greater than its edge, and the second lens has a step structure, to maintain adhesion and suppress peeling and shape changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different kinds of materials are combined in a composite optical element to achieve high optical performance, then optical performance is improved, but adhesion force between materials is low and the materials are liable to peel apart under temperature changes
Solution Approach 1:
An adhesive resin layer is introduced as an intermediary between the optical resin and the lens to improve adhesion. The adhesive resin has specific properties (elastic modulus ratio between 0.2 and 0.5 at different temperatures, and thickness ratio h/t0 between 2.5 and 8.5) that enable it to effectively bond dissimilar materials while accommodating thermal expansion differences, thereby preventing peeling without compromising optical performance.
Solution Approach 2:
The patent uses a composite structure consisting of multiple materials (optical resin, adhesive resin, and lens material) with carefully controlled properties. The adhesive resin forms a composite layer that combines the benefits of strong adhesion with thermal stability, creating a multi-material system that maintains both optical performance and structural integrity under temperature variations.
2Reliability
If different materials with different thermal characteristics are combined in an optical element, then optical performance is improved, but the composite element is liable to undergo shape changes and cracks under temperature changes
Solution Approach 1:
The patent controls critical parameters of the adhesive resin to maintain shape stability. The elastic modulus ratio (Ead2/Ead1) is controlled between 0.2 and 0.5, and the thickness ratio (h/t0) is controlled between 2.5 and 8.5. These parameter controls enable the adhesive layer to accommodate thermal expansion differences between materials, preventing shape changes and cracks while maintaining optical performance.
Solution Approach 2:
The adhesive resin layer acts as a cushioning layer that anticipates and absorbs thermal stress before it can cause damage. By positioning this compliant layer between the optical resin and lens, the structure pre-empts thermal expansion conflicts, allowing differential expansion without transmitting stress that would cause peeling or cracking.
3Strength
If the diameter of lens and optical layer are specified to suppress thermal stress, then peeling is suppressed, but surface shape change remains large in some cases
Solution Approach 1:
The patent applies local quality by creating a step structure on the lens periphery and positioning the adhesive resin specifically in the outer peripheral region. This localized adhesive application targets the area most susceptible to thermal stress (the periphery) while leaving the central optical region unchanged, thus suppressing peeling without significantly affecting overall surface shape.
Solution Approach 2:
The patent addresses the two-dimensional surface shape problem by introducing a third-dimensional solution: a step structure on the lens periphery. This vertical dimension change creates a peripheral region where adhesive can be applied without affecting the central optical surface, thereby suppressing peeling while maintaining optical surface quality.
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
Effectively suppresses peeling and shape changes in optical elements with different materials under temperature variations, maintaining optical performance by using an adhesive resin with elastic modulus ratios and step structure design.
Implementation Method 1
opposing surfaces of the first lens and the optical resin, and/or opposing surfaces of the optical resin and the second lens are joined to each other with the adhesive resin
Implementation Method 2
when an elastic modulus of the adhesive resin at 20° C. is represented by Ead1, and an elastic modulus of the adhesive resin at 60° C. is represented by Ead2, the Ead1 and the Ead2 satisfy a relationship represented by the following formula (1): 0.2≤Ead2/Ead1≤0.5
Implementation Method 3
when a thickness of a center of the optical resin is represented by t0, and a thickness of an outer edge of the optical resin is represented by t1, the t0 is larger than the t1
Implementation Method 4
the first lens is a convex lens
Implementation Method 5
the second lens is a concave lens
Implementation Method 6
the second lens has, on an outer periphery thereof, a step structure thinner than a maximum thickness of the second lens, and wherein when a thickness of the step structure is represented by 'h', the t0 and the 'h' satisfy a relationship represented by the following formula (2). 2.5≤h/t0≤8.5
Data Source
AI summary
An optical element including a first lens, a second lens, and an optical resin arranged between the lenses. The opposing surfaces of the first lens and the optical resin, and/or the opposing surfaces of the optical resin and the second lens are joined to each other with an adhesive resin having a specific elastic modulus. The first lens is a convex lens and the second lens is a concave lens. The thickness of the center of the optical resin is thicker than the thickness of the outer edge of the optical resin. The second lens has, on its outer periphery, a step structure thinner than the maximum thickness of the second lens. The thickness of the step structure and the thickness of the center of the optical resin satisfy a specific relationship.