Polarized Image Sensor Layout for Sensitive Phase Detection
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Solution Overview
Problem
Existing image sensors face challenges in efficiently capturing phase information and image information simultaneously, particularly in reducing diffuse reflection and improving sensitivity for phase detection pixels.
Innovation Solution
The image sensor design includes a substrate with both first pixel regions for generating image information and second pixel regions for phase detection, featuring a grid pattern, polarization patterns, color filters, and a microlens layer. The microlens layer covers both types of pixel regions, and an insulating layer fills unevenness on the second pixel regions' surfaces, preventing light loss and enhancing light reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase detection pixels are added to capture phase information, then the functionality of the image sensor is improved, but the sensitivity and light reception capability of phase detection pixels deteriorate due to diffuse reflection
Solution Approach 1:
The patent applies local quality by creating unevenness portions specifically in the second pixel regions (phase detection pixels) while leaving the first pixel regions (image pixels) flat. This localized structural modification targets only the phase detection areas to reduce diffuse reflection and improve light reception, without affecting the overall sensor functionality.
Solution Approach 2:
The patent converts the harmful effect of diffuse reflection into a beneficial structure by intentionally creating unevenness portions on the phase detection pixel surfaces. These unevenness portions, which could be seen as surface defects, actually serve to reduce diffuse reflection and guide light more effectively into the phase detection pixels, improving sensitivity.
2Reliability
If microlens layer covers both first and second pixel regions, then light reception is improved, but manufacturing complexity increases due to uneven surface topology
Solution Approach 1:
The patent applies preliminary action by forming the unevenness portions in the second pixel regions before depositing the microlens layer. This pre-structuring of the surface topology allows the microlens layer to be deposited over a pre-prepared uneven surface, ensuring proper light guidance into phase detection pixels while simplifying the overall manufacturing process compared to attempting to create unevenness after microlens formation.
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 design significantly improves the sensitivity and reduces diffuse reflection in phase detection pixels, allowing for accurate and efficient image capturing by optimizing the structure and arrangement of pixel regions and light management.
Implementation Method 1
a microlens layer including a plurality of first microlenses on the plurality of first pixel regions, among the plurality of color filters, respectively, and a plurality of second microlenses to cover the plurality of second pixel regions
Implementation Method 2
a plurality of polarization patterns on the insulating layer and partitioning spaces respectively corresponding to the plurality of second pixel regions
Data Source
AI summary
An image sensor includes a substrate having a plurality of first pixel regions configured to generate image information and a plurality of second pixel regions configured to detect phase information, a grid pattern on the substrate and dividing a plurality of spaces corresponding to each of the plurality of first pixel regions and the plurality of second pixel regions. The image sensor also includes a plurality of color filters respectively in first spaces of the plurality of spaces, excluding second spaces corresponding to the plurality of second pixel regions, a plurality of polarization patterns respectively in the second spaces and partitioning the second spaces, and a microlens layer including a plurality of first microlenses respectively on the plurality of color filters.