Resin Composition for Camera Module Lens Holder Bonding
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Solution Overview
Problem
Conventional UV-curing adhesives fail to provide sufficient adhesion strength and position accuracy when bonding lens holders and substrates in camera modules, especially under high-temperature and high-humidity conditions due to increased weight and size of modern lens holders.
Innovation Solution
A resin composition comprising a (meth)acrylate group-containing resin, polyfunctional thiols with specific structures, and a latent curing agent, along with optional polymerization inhibitors and photopolymerization initiators, is used to enhance adhesion strength and durability during heat-curing and high-temperature, high-humidity tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional UV-curing adhesives are used to bond lens holder and substrate, then bonding process is simple and fast, but adhesion strength is insufficient and position accuracy deteriorates after high-temperature and high-humidity durability test
Solution Approach 1:
The patent combines UV-curing and heat-curing mechanisms into a single adhesive system. The adhesive contains both photopolymerization initiators (for UV-curing) and latent curing agents that activate upon heating (for heat-curing). This dual-curing approach merges the simplicity of UV-curing with the durability benefits of heat-curing, resolving the contradiction between process simplicity and reliability under harsh conditions.
Solution Approach 2:
The adhesive is formulated as a composite material containing multiple functional components: (meth)acrylate group-containing resins for polymerization, polyfunctional thiols for crosslinking, photopolymerization initiators for UV activation, and latent curing agents for heat activation. This composite structure enables the adhesive to exhibit both rapid initial setting (UV-curing) and enhanced long-term durability (heat-curing), addressing the reliability issue while maintaining reasonable process complexity.
2Reliability
If lens holder size and weight increase to support larger imaging elements, then imaging quality improves, but adhesion strength and position accuracy of conventional adhesives deteriorate
Solution Approach 1:
The adhesive uses a composite formulation with polyfunctional thiol compounds containing specific cyclic structures (epoxy or alicyclic groups) that provide enhanced crosslinking density and mechanical strength. This composite structure enables the adhesive to maintain strong adhesion to heavier lens holders without requiring changes to the lens holder itself, thus supporting larger imaging elements while preserving bonding reliability.
Solution Approach 2:
The patent modifies the chemical parameters of the adhesive by incorporating latent curing agents that undergo secondary polymerization upon heating. This parameter change (from single-stage to two-stage curing) increases the crosslinking density and thermal stability of the cured adhesive, enabling it to maintain adhesion strength on heavier lens holders that result from increased imaging element sizes.
3Manufacturing precision
If UV-curing adhesive is used for accurate distance maintenance, then position accuracy is good initially, but adhesion strength and position accuracy deteriorate after high-temperature and high-humidity test
Solution Approach 1:
The adhesive incorporates latent curing agents that remain dormant during UV-curing but activate upon subsequent heating. This beforehand cushioning mechanism ensures that the adhesive maintains its initial position accuracy during UV-curing while preparing for enhanced durability through secondary heat-activation. The latent curing agents create a reserve of crosslinking capability that activates under thermal stress, cushioning against the harmful effects of high-temperature and high-humidity environments.
Solution Approach 2:
The dual-curing system provides continuity of useful action by transitioning from UV-curing (initial bonding and position fixation) to heat-curing (durability enhancement). The UV-curing stage establishes initial position accuracy, while the subsequent heat-curing stage continues the polymerization process to enhance crosslinking density and thermal stability. This continuous action ensures both initial precision and long-term durability under harsh conditions.
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 resin composition ensures sufficient adhesion strength during heat-curing and improves position accuracy and durability after high-temperature and high-humidity testing, addressing the limitations of conventional adhesives.
Implementation Method 1
a (meth)acrylate group-containing resin, (b) at least one polyfunctional thiol selected from the group consisting of compounds represented by the following formulas (1) and (2), and (c) a latent curing agent
Implementation Method 2
a photopolymerization initiator, for use in assembling a camera module
Data Source
AI summary
An object of the present invention is to provide an adhesive having sufficient adhesion strength during heat-curing when a lens holder and a substrate on which an imaging element is fixed are bonded in camera module assembly, and also having excellent adhesion strength and position accuracy after a high-temperature and high-humidity durability test after curing. The present invention relates to a resin composition comprises (a) a (meth)acrylate group-containing resin, (b) a specific polyfunctional thiol, and (c) a latent curing agent.