Phase Detection Pixels with Variable Aperture for Depth Sensing
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Solution Overview
Problem
Conventional electronic devices with phase detection capabilities for imaging often require complex arrangements of multiple image sensors and camera lenses, leading to reduced spatial resolution, increased cost, and inaccurate depth calculations due to varying angular responses of phase detection pixels.
Innovation Solution
An image sensor with phase detection pixel groups, where pairs of pixels have asymmetric angular responses and are covered by a single microlens, allowing for improved phase detection and depth sensing capabilities by determining phase differences to adjust optics for focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple image sensors and camera lenses are used for depth sensing, then depth sensing capability is provided, but spatial resolution is reduced and device complexity increases
Solution Approach 1:
The patent combines phase detection pixels and image capture pixels into a single image sensor array, eliminating the need for separate depth sensing and image capture sensors. This integration reduces device complexity while maintaining depth sensing capability through the phase detection pixels that can determine distance information from the same sensor plane.
Solution Approach 2:
The image sensor is designed to perform multiple functions: capturing images through image pixels and sensing depth through phase detection pixels within the same sensor array. This multi-functional approach eliminates the need for separate dedicated depth sensing hardware, reducing overall device complexity.
2Measurement precision
If multiple image sensors and camera lenses are used for depth sensing, then depth sensing capability is provided, but spatial resolution is reduced
Solution Approach 1:
By integrating phase detection pixels within the same sensor array as image pixels, the patent maintains full spatial resolution for both depth sensing and image capture. The phase detection pixels are distributed throughout the array and can determine depth information without compromising the spatial resolution of the overall image sensor.
3Device complexity
If phase detection pixels are used in a pixel array, then on-chip phase detection is achieved, but angular response varies by position leading to inaccurate depth calculations
Solution Approach 1:
The patent introduces a variable aperture that can dynamically adjust its size to compensate for position-dependent angular response variations in phase detection pixels. By changing the aperture size, the system can normalize the angular response across different pixel positions in the array, improving depth calculation accuracy while maintaining on-chip phase detection capability.
4Measurement precision
If a variable aperture is introduced to compensate for angular response variation, then depth calculation accuracy is improved, but device complexity increases
Solution Approach 1:
The variable aperture is integrated into the existing image sensor system, working in conjunction with the phase detection pixels already present in the pixel array. This integration allows the aperture to compensate for angular response variations without requiring entirely separate depth sensing hardware, thereby improving depth calculation accuracy with minimal additional complexity.
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 accuracy of depth sensing and automatic focusing by providing improved phase detection data, leading to better image resolution and reduced complexity in electronic devices.
Implementation Method 1
Each group of four phase detection pixels is covered by a single microlens
Implementation Method 2
Each pixel receives incident photons (light) and converts the photons into electrical signals
Data Source
AI summary
An imaging system may include an image sensor with phase detection pixel groups for depth sensing or automatic focusing operations. Each phase detection pixel group may have two or more photosensitive regions covered by a single microlens so that each photosensitive region has an asymmetric angular response. The imaging system may use image data from the phase detection pixel group to determine a phase difference. Alternatively, to improve accuracy, the imaging system may obtain two sets of image data using two different aperture sizes. The phase difference associated with each aperture size may be determined. The difference between the two phase differences may be determined and used as a more accurate metric for depth sensing or automatic focusing operations.