RGB-IR Dual-Photodiode Image Sensor for Fast Depth Focusing

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Solution Overview

Problem

Existing image sensors in intelligent electronic products are limited to natural light photography, unable to detect object distance, leading to restricted photographing scenarios and slow focusing, affecting user experience.

Innovation Solution

Implementing an RGB-IR pixel array layout with dual photodiode pixels, allowing infrared light reception for object distance detection and enabling quick focusing, bokeh, and three-dimensional photography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the Bayer pixel array layout is used, then the image sensor can receive natural light and take images under normal illumination, but it cannot detect object distance, limiting photographing scenarios

Engineering Contradiction:
Improvephotographing scenariosVSAvoidobject distance detection capability
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The pixel array is segmented into different types of pixels: some pixels are configured with infrared subpixels for distance detection, while other pixels maintain RGB subpixels for color imaging. This segmentation allows the image sensor to simultaneously perform both distance detection and natural light photography, resolving the contradiction between adaptability and information loss

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The image sensor is designed with multi-functionality by integrating both infrared detection capability (for distance measurement) and visible light detection capability (for color imaging). Each pixel unit can function as either an infrared detection pixel or a color imaging pixel, enabling the sensor to handle multiple photographing scenarios including depth mapping, night photography, and standard color imaging

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of information

If the 2PD pixel array layout is used, then object distance can be detected, but only natural light can be received, limiting photographing scenarios

Engineering Contradiction:
Improveobject distance detection capabilityVSAvoidphotographing scenarios
Core Design Contradiction:
Loss of informationVSAdaptability or versatility

Solution Approach 1:

The pixel array is divided into different functional regions: pixels with dual photodiodes for infrared distance detection and pixels with RGB filters for color imaging. This segmentation enables the sensor to perform both distance detection and receive natural light, achieving multi-scenario photography capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The image sensor employs a composite pixel structure combining different photodiode configurations (dual photodiode for infrared, single photodiode with RGB filters for visible light) within the same sensor array. This composite structure allows simultaneous operation of distance detection and color imaging functions

Inventive Principle:
Principle #40Composite materials

3Productivity

If traditional focusing methods are used, then the image sensor can capture images, but focusing is slow, affecting user photographing experience

Engineering Contradiction:
Improvefocusing speedVSAvoidfocusing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent replaces mechanical focusing methods with optical phase detection using dual photodiodes. By detecting the phase difference of infrared light reflected from the object, the system can calculate object distance and adjust focus automatically without mechanical movement, significantly improving focusing speed and reducing focusing time

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The image sensor performs self-focusing by using its own infrared detection capability to measure object distance and automatically adjust the lens focus. This self-service mechanism eliminates the need for external autofocus assistance and enables rapid automatic focusing

Inventive Principle:
Principle #25Self-service

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

Enhances imaging effects by enabling dark-state imaging and quick focusing, while improving user experience through three-dimensional photography and related application functions.

Implementation Method 1

the pixel unit includes a first pixel and a second pixel adjacent to the first pixel, the first pixel includes a red subpixel, a green subpixel, and a blue subpixel, the second pixel includes a red subpixel, a green subpixel, and an infrared subpixel

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3826285B1Image sensor, mobile terminal, and photographing method
Publication Date: 2025.12.17 VIVO MOBILE COMM CO LTD
  • EP3826285B1 patent drawingFigure 1a~1c
  • EP3826285B1 patent drawingFigure 2a~3c
  • EP3826285B1 patent drawingFigure 3d~4c

AI summary

An image sensor, a mobile terminal and a photographing method are provided. The image sensor includes: a pixel array, where the pixel array includes a preset quantity of pixel units arranged in a predetermined manner, the pixel unit includes a first pixel and a second pixel adjacent to the first pixel, the first pixel includes a red subpixel, a green subpixel, and a blue subpixel, the second pixel includes a red subpixel, a green subpixel, and an infrared subpixel, and both the first pixel and the second pixel are dual photodiode pixels, where a location of the blue subpixel in the first pixel is the same as that of the infrared subpixel in the second pixel, and each of the first pixel and the second pixel includes four dual photodiode subpixels.