Waveguide Partition Grid Width Variation for Imaging Sensor Sensitivity
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Solution Overview
Problem
In solid-state imaging devices, the peripheral areas experience non-uniform photoelectric conversion element sensitivities due to oblique incident light and varying refractive indexes of color filter segments, leading to challenges in achieving uniform image capture.
Innovation Solution
A solid-state imaging device with a waveguide partition grid having varying widths, where the top width is greater than the bottom width, is introduced to improve sensitivity uniformity by guiding oblique incident light more effectively and reducing sensitivity differences between color filter segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to increase the number of pixels for high-resolution images, then image resolution is improved, but sensitivity uniformity in peripheral areas deteriorates due to oblique incident light
Solution Approach 1:
The waveguide partition grid is designed with different grid widths in different regions: a first grid width in the central area and a second grid width (larger than the first) in the peripheral area. This local differentiation compensates for the non-uniform sensitivity caused by oblique incident light in peripheral regions, thereby improving sensitivity uniformity across the entire sensor surface while maintaining high pixel density for high-resolution imaging.
Solution Approach 2:
The patent changes the physical parameter of the waveguide partition grid width to address sensitivity uniformity. By increasing the grid width in peripheral areas compared to central areas, the optical path and light distribution are modified to compensate for the effects of oblique incident light, thus improving sensitivity uniformity without requiring changes to pixel size or number.
2Ease of manufacture
If the waveguide partition grid has uniform grid widths, then manufacturing is simplified, but sensitivity uniformity in peripheral areas deteriorates due to oblique incident light
Solution Approach 1:
The waveguide partition grid is designed with different grid widths in different regions: a first grid width in the central area and a second grid width (larger than the first) in the peripheral area. This local differentiation compensates for the non-uniform sensitivity caused by oblique incident light in peripheral regions, thereby improving sensitivity uniformity across the entire sensor surface.
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 solution enhances sensitivity uniformity in the edge and peripheral areas of the imaging device, improving image capture quality by adjusting the waveguide partition grid widths to align with the color filter segments, thereby reducing sensitivity disparities.
Implementation Method 1
an optical waveguide layer over the color filter layer. The optical waveguide layer includes a waveguide partition grid
Implementation Method 2
an anti-reflection film on the waveguide partition grid and the waveguide material
Data Source
AI summary
A solid-state imaging device having a first area and a second area surrounding the first area is provided. The solid-state imaging device includes a substrate having a plurality of photoelectric conversion elements. The solid-state imaging device also includes a color filter layer disposed on the substrate. The color filter layer includes a plurality of color filter segments corresponding to the plurality of photoelectric conversion elements. The solid-state imaging device further includes an optical waveguide layer over the color filter layer. The optical waveguide layer includes a waveguide partition grid, a waveguide material in spaces of the waveguide partition grid, and an anti-reflection film on the waveguide partition grid and the waveguide material. The width of the top of the waveguide partition grid is larger than the width of the bottom of the waveguide partition grid.