Image Sensor Low-Refractive Index Pattern Light Leakage
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Solution Overview
Problem
Image sensors face issues with light leakage and reduced light reception rates due to the direction of incident light on charge storage portions, which affects the efficiency of photoelectric conversion.
Innovation Solution
The design includes a substrate with a charge storage portion and a low-refractive index pattern on a light-blocking pattern, where micro lenses are positioned to redirect incident light from the charge storage portion to the photoelectric conversion portion, preventing light leakage and enhancing light reception by using a low-refractive index pattern that overlaps with the micro lenses and light-blocking pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If light-blocking pattern is disposed on the charge storage portion, then light leakage is blocked, but light reception rate decreases due to light being blocked from reaching photoelectric conversion portions
Solution Approach 1:
A low-refractive index pattern is introduced as an intermediary element between the light-blocking pattern and the micro lens. This low-refractive index pattern acts as a mediator that redirects light paths, allowing light to bypass the charge storage portion and reach the photoelectric conversion portions effectively, thus maintaining both light leakage blocking and high light reception rate
Solution Approach 2:
The refractive index parameter is strategically varied by introducing a low-refractive index pattern with refractive index different from surrounding materials. This parameter change creates optical path differences that redirect light towards photoelectric conversion portions while maintaining the light-blocking function over the charge storage portion
2Manufacturing precision
If micro lens is positioned directly over charge storage portion, then light focusing is improved, but light leakage occurs towards charge storage portion
Solution Approach 1:
The low-refractive index pattern serves as an intermediary optical element between the micro lens and the charge storage portion. It modifies the light path by refraction, redirecting light that would otherwise leak into the charge storage portion towards the photoelectric conversion portions, thus eliminating light leakage while preserving focusing precision
Solution Approach 2:
Different regions of the optical path are assigned different refractive index qualities. The low-refractive index pattern is locally positioned to create specific refraction effects that redirect light away from the charge storage portion, while other regions maintain their original optical properties for proper light focusing
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 effectively inhibits light leakage and increases light reception rates by redirecting incident light towards the photoelectric conversion portions, improving the overall efficiency of the image sensor.
Implementation Method 1
a low-refractive index pattern on a light-blocking pattern... redirecting incident light from the charge storage portion to the photoelectric conversion portion
Data Source
AI summary
An image sensor includes a substrate having a first surface, a charge storage portion disposed in the substrate, a light-blocking pattern disposed on the first surface overlapping the charge storage portion, and a low-refractive index pattern on the light-blocking pattern.