Image Sensor Shields for Global Shutter and Autofocus
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Solution Overview
Problem
Current image sensors lack the combination of auto-focusing and global shutter functions, which are essential for high-performance applications in digital cameras and other imaging devices, and often require additional storage elements that increase complexity and cost.
Innovation Solution
The design incorporates a structure with first and second sub-pixels, each containing a photodiode and storage diode, along with upper and lower shields that optically shield the storage diodes and active regions, enabling both auto-focusing and global shutter functions without the need for additional storage elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional storage elements are added to achieve global shutter function, then global shutter capability is improved, but device complexity increases
Solution Approach 1:
The patent makes photodiodes serve dual functions: they act as both photoelectric conversion elements and storage elements for the global shutter function. By configuring specific photodiodes (e.g., PD1 and PD2) to function as storage elements, the sensor achieves global shutter capability without requiring separate storage structures, thereby reducing device complexity while maintaining functionality
Solution Approach 2:
The patent merges the photoelectric conversion function and storage function into a single photodiode structure. The photodiode simultaneously performs light-to-electricity conversion and temporary charge storage, eliminating the need for distinct storage elements and simplifying the overall device architecture
2Object-affected harmful factors
If shields are added to optically shield storage diodes, then optical shielding performance is improved, but device complexity increases
Solution Approach 1:
The patent introduces upper and lower shields that vertically overlap with storage diodes from different spatial dimensions. The upper shield is positioned above the substrate while the lower shield is positioned below the substrate, creating three-dimensional optical shielding that effectively blocks stray light without requiring complex lateral shielding structures
Solution Approach 2:
The optical shielding function is divided into two separate components: an upper shield and a lower shield. Each shield independently addresses optical interference from its respective direction, and together they provide comprehensive shielding performance while maintaining structural simplicity
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
This configuration allows for efficient conversion of optical images into electrical signals with both auto-focusing and global shutter capabilities, enhancing image sensor performance in various applications while simplifying the design and reducing costs.
Implementation Method 1
a first photodiode and a first storage diode, and the second sub-pixel includes a second photodiode and a second storage diode
Implementation Method 2
an upper shield, wherein the first sub-pixel includes a first photodiode and a first storage diode, and the second sub-pixel includes a second photodiode and a second storage diode, and the upper shield is formed over the first and second storage diodes to vertically overlap with the first and second storage diodes
Data Source
AI summary
An image sensor includes: a first sub-pixel and a second sub-pixel that are adjacent to each other; and an upper shield, wherein the first sub-pixel includes a first photodiode and a first storage diode, and the second sub-pixel includes a second photodiode and a second storage diode, and the upper shield is formed over the first and second storage diodes vertically overlap with the first and second storage diodes.