Image Sensor Light Refraction Pattern Auto-Focus Crosstalk
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Solution Overview
Problem
Image sensors experience degraded auto-focus function and increased crosstalk between pixels due to high incident angles of light, which current technologies fail to effectively address.
Innovation Solution
Incorporating a light refraction pattern with a center refraction pattern and side refraction patterns of different optical refractive indices, aligned with photodiode isolation regions, to control and reduce the incident angle of light on pixels, thereby improving auto-focus and reducing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light refraction patterns are added to control incident angle, then auto-focus function and crosstalk reduction are improved, but device complexity increases
Solution Approach 1:
The light refraction pattern is divided into multiple regions with different refractive indices: a first light refraction pattern region with a first refractive index and a second light refraction pattern region with a second refractive index. This segmentation allows different portions of the lens to refract light at different angles, effectively controlling incident light angles to improve auto-focus function and reduce crosstalk while maintaining a relatively simple overall lens structure.
Solution Approach 2:
Different regions of the lens are assigned different refractive indices to perform different functions. The first light refraction pattern region and the second light refraction pattern region have distinct optical properties tailored to their specific roles in light control, enabling localized optimization of light refraction to address auto-focus and crosstalk issues without requiring complete structural redesign.
2Reliability
If light refraction patterns are added to control incident angle, then crosstalk reduction is improved, but manufacturing complexity increases
Solution Approach 1:
The lens is segmented into multiple light refraction pattern regions with different refractive indices that can be manufactured using standard multi-layer lamination techniques. Each region can be formed as a separate layer or zone, allowing for controlled fabrication of the complex refraction pattern using existing manufacturing processes rather than requiring entirely new fabrication methods.
Solution Approach 2:
The lens employs composite material construction with multiple layers having different refractive indices. This allows the complex light refraction pattern to be achieved by stacking and combining material layers with known optical properties, leveraging established composite material fabrication techniques to manage manufacturing complexity while achieving the desired optical performance for crosstalk reduction.
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 light refraction pattern effectively reduces light loss and enhances the collection of incident light, improving the auto-focus function and minimizing cross-talk between photodiodes by refracting diagonal incident light to more vertically aligned paths.
Implementation Method 1
a light refraction pattern formed on the photodiode... capable of changing a light propagation direction... The light refraction pattern effectively reduces light loss and enhances the collection of incident light, improving the auto-focus function and minimizing cross-talk between photodiodes by refracting diagonal incident light to more vertically aligned paths
Data Source
AI summary
An image sensor is provided. The image sensor may include a photodiode formed in a substrate; a light refraction pattern formed on the photodiode; a color filter covering the light refraction pattern; and a micro-lens formed on the color filter.