Dual-Pixel Image Sensor Layout With IR Subpixels for Low-Light Focus
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Solution Overview
Problem
Existing pixel array arrangements in image sensors, such as the four-in-one RGB and dual pixel focusing (2PD) technologies, suffer from slow focusing and inadequate dark-state capturing effects, affecting user experience in capturing images, especially in low-light conditions.
Innovation Solution
An image sensor with a 2PD pixel array combining RGB subpixels and an infrared subpixel in a four-in-one arrangement, allowing for fast focusing and improved dark-state imaging by detecting object distance and utilizing infrared light for enhanced capturing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a four-in-one RGB pixel array arrangement is used, then the dark-state photographing effect is improved compared to Bayer mode, but the object distance cannot be detected and focusing speed is slow
Solution Approach 1:
The patent combines the four-in-one RGB pixel arrangement with dual pixel focusing (2PD) technology, merging the advantages of both approaches. The pixel array integrates color filtering for RGB channels with phase detection capabilities, allowing simultaneous color imaging and distance detection. This merging resolves the contradiction by enabling both improved dark-state performance and fast focusing through phase detection.
Solution Approach 2:
The pixel array is designed to perform multiple functions: color image capture through RGB subpixels and object distance detection through phase detection pairs. Each pixel contains both color filtering elements and phase detection capability, making the system universal and eliminating the need for separate sensors for different functions.
2Speed
If dual pixel focusing 2PD technology is used, then object distance detection and focusing speed are improved, but the dark-state photographing effect is non-ideal
Solution Approach 1:
The patent applies different subpixel configurations to different regions or purposes within the pixel array. Some pixels are optimized for color capture with full RGB subpixels, while others incorporate infrared subpixels for enhanced dark-state performance. This local differentiation allows the system to maintain fast focusing through phase detection while improving dark-state photography in specific regions.
Solution Approach 2:
The pixel array uses a composite structure combining multiple types of subpixels (RGB and infrared) within the same pixel unit. This composite approach allows the system to leverage the wavelength sensitivity of different subpixel types, with infrared subpixels contributing to dark-state imaging while RGB subpixels maintain color accuracy and phase detection pairs enable fast focusing.
3Reliability
If infrared subpixels are added to the pixel array, then dark-state imaging capability is improved, but the device complexity increases
Solution Approach 1:
The pixel array is segmented into different pixel types with specific subpixel configurations. Some pixels contain full RGB subpixels for color imaging, while others include infrared subpixels for dark-state enhancement. This segmentation allows the system to add infrared capability without requiring every pixel to contain all subpixel types, thereby managing complexity through functional specialization.
Solution Approach 2:
The patent extends the pixel array functionality by adding infrared wavelength sensitivity as another dimension of detection beyond the visible spectrum. This dimensional extension allows dark-state imaging through infrared light detection while maintaining the existing RGB color imaging capability, effectively adding a new operational mode without fundamentally redesigning the entire pixel structure.
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 enables rapid focusing, improved bokeh effects, and the implementation of stereophotographing functions, enhancing the functionality and user experience of mobile terminals while capturing images, especially in low-light conditions.
Implementation Method 1
the second pixel comprises the green subpixel, an infrared subpixel, and at least one of the red subpixel or the blue subpixel
Implementation Method 2
each of some R, G and B subpixels in a pixel array is divided into two, and obtains different light energy according to different incident directions, so that a left subpixel point and a right subpixel point form a phase detection pair
Implementation Method 3
The first photodiode is respectively connected to the red subpixel, the green subpixel, the blue subpixel and the infrared subpixel
Data Source
AI summary
Image sensor, mobile terminal, image capturing method are provided. Pixel array of image sensor includes preset quantity of pixel units, pixel unit includes first and second pixels that are dual pixel focusing pixels, first pixel includes red, green, and blue subpixels, second pixel includes green subpixel and infrared subpixel, and at least one of red and blue subpixels, and each subpixel is arranged in four-in-one manner; position of infrared subpixel in second pixel is same as position of red subpixel, green subpixel, blue subpixel, first combination of subpixels, or second combination of subpixels in first pixel; or position of half the infrared subpixel in second pixel is same as position of half the red subpixel, half the green subpixel, or half the blue subpixel in first pixel, and half an infrared subpixel in each of two adjacent second pixels is combined to form entire infrared subpixel.