Curved Image Sensor Bonding Pattern for Field Curvature Correction
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Solution Overview
Problem
Current image sensors face challenges with lens aberrations like field curvature, which cause focal position differences between the central and peripheral portions of the imaging surface, leading to suboptimal image capture.
Innovation Solution
A curved image sensor is designed with a three-dimensionally curved surface aligned with the imaging lens, featuring a bonding pattern with a donut shape that seals a cavity between substrates, ensuring the curved surface remains intact and improving fabrication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a flat image sensor is used, then the fabrication process is simple, but lens aberration (field curvature) cannot be corrected
Solution Approach 1:
The image sensor employs a curved surface instead of a flat surface to match the field curvature of the imaging lens. This curvature allows the sensor to correct lens aberrations by aligning its imaging plane with the curved focal surface of the lens, thereby improving image quality across the entire field of view without requiring complex optical correction systems
2Productivity
If a curved image sensor is fabricated using conventional methods, then lens aberration is corrected, but fabrication efficiency is low
Solution Approach 1:
The fabrication process is divided into distinct stages: first forming the curved surface on the image sensor substrate, then bonding it to a separate support substrate, and finally sealing the structure. This segmentation allows each stage to be optimized independently, improving overall fabrication efficiency while maintaining the integrity of the curved surface
Solution Approach 2:
The curved surface is formed on the image sensor substrate before bonding to the support substrate. This preliminary formation of the curved geometry allows subsequent processing steps to be performed on a stable, pre-shaped structure, reducing the risk of deformation and improving fabrication efficiency
3Stability of the object's composition
If substrates are bonded without a sealing structure, then fabrication is simpler, but the curved shape cannot be maintained
Solution Approach 1:
The bonding pattern is designed with a donut shape that provides localized bonding strength at critical regions while maintaining overall structural integrity. This selective bonding approach ensures the curved shape is maintained where needed without requiring complete coverage, reducing complexity while preserving shape stability
Solution Approach 2:
A sealing material is introduced as an intermediary substance that fills the bonding pattern and provides both mechanical support to maintain the curved shape and hermetic sealing to protect internal components. This intermediary element simultaneously addresses shape maintenance and protection requirements
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 curved image sensor effectively corrects field curvature aberrations, enhancing image capture quality and reducing package size by maintaining the curved shape through efficient bonding and sealing, thereby improving fabrication efficiency and integration.
Implementation Method 1
a bonding pattern formed over a second surface opposite to the first surface of the first substrate, formed along an edge of the first substrate
Implementation Method 2
a sealing material filling the opening so that a cavity defined by the first substrate, the second substrate, and the bonding pattern is sealed by the sealing material
Data Source
AI summary
The curved image sensor may include: a first substrate including a plurality of photoelectric conversion elements and having a curved first surface; a bonding pattern formed over a second surface opposite to the first surface of the first substrate, formed along an edge of the first substrate, and having an opening; a second substrate bonded to the second surface of the first substrate by the bonding pattern; and a sealing material filling the opening so that a cavity defined by the first substrate, the second substrate, and the bonding pattern is sealed by the sealing material.