Wafer-Level Camera Module Stray Light Prevention
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Solution Overview
Problem
The wafer level lens process for manufacturing compound eye camera modules faces challenges in preventing stray light between adjacent lenses, particularly during the lamination of multiple layers, which affects the accuracy and effectiveness of the lens structure.
Innovation Solution
A camera module design that includes a stacked lens substrate with through-holes for optical units, a light-receiving unit, and a groove portion between them, optionally featuring a light-absorbing film or blocking plate to mitigate stray light, and a method for producing this structure through direct bonding of substrates without using resin, ensuring precise alignment and preventing deformation due to thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin is used for bonding wafer substrates in the wafer level lens process, then lamination can be achieved, but curing contraction and thermal expansion cause deformation and reduce positioning accuracy
Solution Approach 1:
The patent extracts and removes the resin bonding material from the lamination process. Instead of using resin that causes curing contraction and thermal expansion deformation, the invention directly bonds wafer substrates using their inherent properties, eliminating the harmful intermediate material that compromises positioning accuracy.
Solution Approach 2:
The patent employs direct bonding between wafer substrates, creating a composite structure where the substrates themselves serve as the bonding interface. This eliminates the need for separate resin materials and their associated deformation issues, achieving both lamination and high precision.
2Adaptability or versatility
If multiple layers are laminated to create complex lens structures, then optical functionality is improved, but stray light between adjacent lenses increases
Solution Approach 1:
The patent segments the space between adjacent optical units by introducing groove portions that extend from the front surface to the back surface of the lens substrate. These grooves divide the continuous space into isolated compartments, preventing stray light from one optical unit from reaching adjacent light receiving units while maintaining the multi-layer lamination structure.
Solution Approach 2:
The groove portions act as intermediary structures between adjacent optical units. They serve as physical barriers that mediate the interaction between neighboring lenses, blocking stray light paths while allowing the optical units to maintain their functional configurations.
3Ease of manufacture
If resin is used for bonding, then substrate lamination is enabled, but thermal expansion during curing causes deformation
Solution Approach 1:
The patent removes the resin bonding material that causes thermal expansion deformation during curing. By enabling direct bonding between wafer substrates, the invention eliminates the intermediate material that undergoes thermal expansion, thereby maintaining substrate shape stability while achieving secure lamination.
4Reliability
If groove portions are added to prevent stray light, then optical performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the groove formation process with the existing wafer level lens manufacturing process. The grooves are formed as integral parts of the lens substrate during the same fabrication sequence, combining multiple functions (structural support, stray light blocking, and optical positioning) into a unified structure rather than adding separate components.
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 prevents stray light and maintains high accuracy in lens positioning, enabling the successful lamination of multiple layers and improving the camera module's optical performance by eliminating resin-related issues like curing contraction and thermal expansion.
Implementation Method 1
at least one of a light-absorbing film or a blocking plate provided between the first light-receiving unit and the second light-receiving unit
Implementation Method 2
A groove portion is disposed between at least a portion of the first optical unit and at least a portion of the second optical unit in the stacked lens substrates
Data Source
AI summary
Provided is a camera module including: a laminated lens structure in which substrates with lenses, each of which has a lens disposed inside a through-hole formed in the substrate, are bonded by direct bonding and laminated, the laminated lens structure including a plurality of optical units each of which has a plurality of the lenses laminated in an optical axis direction; and at least one of a light absorbing film and a blocking plate provided between the adjacent optical units.