Multi-Height Pixel Layout to Reduce Image Sensor Shadowing
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Solution Overview
Problem
Image sensors with pixels of different height levels suffer from shadowing effects due to varying light incidence angles and finished heights, which restrict design flexibility and performance.
Innovation Solution
An image sensor array with pixels arranged to minimize height differences between neighboring pixels, where each pixel can take one of N height levels, with adjacent pixels having a height level equal to n-1 in scanning directions, reducing shadowing and allowing for relaxed design constraints on light incidence angles and pixel heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixels are arranged with different height levels to optimize color filtering and depth sensing, then pixel functionality and measurement precision are improved, but shadowing effects increase and block light from reaching intended pixels
Solution Approach 1:
The patent applies local quality by assigning different height levels to pixels based on their specific function (color filtering vs. depth sensing) and their position in the array. Pixels are individually configured with optimal heights for their intended purpose, while the overall arrangement ensures that higher pixels do not cast shadows on lower pixels through strategic positioning relative to the optical axis.
2Adaptability or versatility
If pixels with different height levels are arranged arbitrarily, then design flexibility is improved, but shadowing effects increase and undermine sensor performance
Solution Approach 1:
The patent employs asymmetry by arranging pixels with different height levels in a non-uniform pattern that is specifically optimized to prevent shadowing. The asymmetric arrangement ensures that pixels at higher levels are positioned such that they do not block light paths to pixels at lower levels, while still maintaining the design flexibility to have varied pixel heights for different functions.
3Adaptability or versatility
If large angles of incident light are allowed, then optical system design freedom is improved, but shadowing effects increase and block light before reaching intended pixels
Solution Approach 1:
The patent resolves the contradiction by introducing a vertical dimension (height level) to the pixel arrangement. Instead of being constrained to a single plane, pixels are distributed across multiple height levels in a three-dimensional configuration. This dimensional change allows the optical system to accommodate larger incident light angles while preventing shadowing through the vertical separation of pixels at different heights.
Data Source
AI summary
The present disclosure relates to an image sensor (21) comprising an array of pixels, wherein a set of pixels of the array comprises pixels with different height levels arranged according to their height level and relative position to an optical axis (22) of the image sensor, wherein each pixel of the set can take one height level i among N different height levels, N≥2, where i=1 is the smallest height level and i=N is the highest height level. According to the disclosure, for a pixel of the set having a first height level equal to n, 2≥n≥N, and an adjacent pixel of the set having a second height level equal to m, lower than the first height level, in at least one of horizontal, vertical, or diagonal scanning direction, from a point at which the optical axis (22) intersects the image sensor (21) to at least one rim of the image sensor, the second height level m is equal to n−1.