Meta-Microlens Image Sensor Layout for Edge Pixel Sensitivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As image sensors become more compact, the chief ray angle at the edge of the optical sensor increases, leading to decreased pixel sensitivity and degradation in the sensitivity of the optical sensor or imaging module.
Innovation Solution
The image sensor incorporates a pixel array with unit pixels featuring photoelectric conversion elements arranged in a matrix on a semiconductor substrate, accompanied by color filters and meta-microlenses. The meta-microlenses include first and second nanostructures with different refractive indexes, where the diameters of nanoposts in the meta-microlenses increase from the center to the edge of the pixel array, and the refractive index peak region is strategically positioned and shifted depending on the position within the pixel array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical sensor is made compact, then the size of the imaging module is reduced, but the chief ray angle at the edge increases causing decreased pixel sensitivity
Solution Approach 1:
The patent applies local quality by making the nanopost diameters position-dependent within the pixel array. Specifically, nanoposts at the edge of the pixel array have larger diameters than those at the center, creating spatially varying optical properties that compensate for the increased chief ray angle at the edge and maintain uniform pixel sensitivity across the sensor surface.
Solution Approach 2:
The patent changes the physical parameter of nanopost diameter based on position within the pixel array. By increasing the diameter of nanoposts at the edge compared to the center, the optical path and light condensing characteristics are modified to compensate for oblique incident light, thereby resolving the sensitivity degradation caused by compact sensor design.
2Reliability
If the nanopost diameters are increased at the edge of the pixel array, then the light receiving efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent implements parameter changes by varying the nanopost diameter as a continuous or discrete function of position within the pixel array. This approach allows optimization of light receiving efficiency at the edge while maintaining a systematic manufacturing process that can be implemented through standard photolithography and etching techniques with appropriate patterning.
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 enhances the light receiving efficiency and sensitivity of the image sensor, particularly at the edge of the pixel array, while also improving auto focusing performance by optimizing light condensing and phase correction based on incident light conditions.
Implementation Method 1
Each of the meta-microlenses includes first and second nanostructures having different refractive indexes. The first nanostructure is implemented with a plurality of nanoposts
Data Source
AI summary
Disclosed is an image sensor which includes a pixel array including a plurality of unit pixels having photoelectric conversion elements arranged in a matrix form on a semiconductor substrate in a first direction and a second direction crossing the first direction, color filters corresponding to the unit pixels and having at least two different colors, and meta-microlenses on the color filters and configured to condense light incident to the unit pixels.