Hybrid 3D Image Sensor Combining Phase Detection and Time-of-Flight
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Solution Overview
Problem
Conventional imaging systems face challenges in achieving accurate three-dimensional imaging due to the complexity and cost associated with multiple image sensors and lens arrays, as well as poor performance in low light or textured scenes using phase detection pixels.
Innovation Solution
The implementation of hybrid three-dimensional imaging pixel groups that combine phase detection and time-of-flight functionality, allowing for accurate depth sensing and improved performance in various settings by using pixel pairs with asymmetric angular responses and additional time-of-flight photodiodes, enabling parallel readout and enhanced substrate area utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple image sensors and camera lenses are used to capture images from various viewpoints for depth sensing, then three-dimensional imaging capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple depth sensing functionalities (phase detection and time-of-flight) into a single image sensor device. Different pixel types are integrated within the same sensor array, allowing the device to perform both conventional imaging and various depth measurement techniques without requiring separate sensors and lenses for each function.
Solution Approach 2:
The image sensor is designed with multi-functional pixels that can perform both standard imaging and depth sensing operations. The sensor can switch between different measurement modes (phase detection, time-of-flight) and can capture both 2D images and 3D depth information using the same hardware platform.
2Adaptability or versatility
If multiple image sensors and camera lenses are used to capture images from various viewpoints for depth sensing, then three-dimensional imaging capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple depth sensing functionalities (phase detection and time-of-flight) into a single image sensor device. Different pixel types are integrated within the same sensor array, allowing the device to perform both conventional imaging and various depth measurement techniques without requiring separate sensors and lenses for each function.
3Measurement precision
If lenticular arrays are added to focus incident light on sub-regions of a two-dimensional pixel array for depth sensing, then depth measurement capability is improved, but spatial resolution decreases
Solution Approach 1:
The image sensor array is segmented into different pixel types (phase detection pixels and time-of-flight pixels) that are distributed throughout the sensor. Each pixel type is optimized for its specific function while maintaining overall spatial resolution through proper pixel arrangement and sizing.
Solution Approach 2:
Different regions of the sensor array have different pixel characteristics optimized for specific functions. Phase detection pixels use asymmetric angular responses for directional light detection, while time-of-flight pixels are optimized for modulated light detection, allowing each region to excel at its designated task without compromising overall image quality.
4Measurement precision
If phase detection pixels are used for depth sensing, then depth measurement capability is improved, but performance deteriorates in low light or textured scenes
Solution Approach 1:
The patent employs two different measurement parameters: phase detection pixels measure the phase shift of reflected light for depth calculation, while time-of-flight pixels measure the time delay of modulated light. By changing the measurement parameter based on lighting conditions, the system maintains reliable depth sensing performance across varying environmental conditions.
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 solution enables robust and high-quality three-dimensional imaging, improving performance in low light conditions and textured scenes, while reducing complexity and cost by integrating phase detection and time-of-flight capabilities within a single image sensor.
Implementation Method 1
Each pixel receives incident photons (light) and converts the photons into electrical signals
Implementation Method 2
a third photodiode formed in the second substrate and configured to obtain time-of-flight information
Data Source
AI summary
Image sensors may include hybrid three-dimensional imaging pixel groups. The pixel groups may be capable of obtaining both phase detection information and time-of-flight information. A pixel group may have first and second photodiodes covered by a single microlens that are used to obtain phase detection information. The microlens may also cover a third photodiode that obtains time-of-flight information. The first and second photodiodes may be formed in a first substrate whereas the third photodiode may be formed in a second substrate. The first and second substrates may be connected by a metal interconnect layer.