Image Pickup Element Segmented Pixel Array for Phase Detection

Solution Overview

Problem

Existing image pickup elements with two photodiodes per pixel require twice the time to read out signals compared to those with a single photodiode, hindering simultaneous image pickup and phase difference focus detection efficiency.

Innovation Solution

The image pickup element is configured with a pixel array featuring both first unit pixels with multiple photoelectric conversion units and second unit pixels with fewer units, utilizing separate column output lines to reduce readout time while maintaining phase difference detection capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two photodiodes are provided in one pixel for phase difference detection, then focus detection capability is improved, but signal reading time increases approximately twice

Engineering Contradiction:

Improvephase difference detection capabilityVSAvoidsignal reading time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The pixel array is divided into two distinct types: first unit pixels with M photodiodes for phase difference detection, and second unit pixels with N photodiodes for standard imaging. This segmentation allows independent readout paths for each pixel type, enabling parallel processing and reducing overall readout time while maintaining focus detection capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to the pixel structure by varying the number of photodiodes per pixel (M vs N) and assigning different readout resources (first column output lines vs second column output lines). This dimensional differentiation enables simultaneous readout of multiple pixel types through separate channels, resolving the time conflict.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple photoelectric conversion units are provided per pixel, then phase difference detection is enabled, but device complexity increases

Engineering Contradiction:

Improvephase difference detection capabilityVSAvoidpixel structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pixel array is divided into two distinct types: first unit pixels with M photodiodes for phase difference detection, and second unit pixels with N photodiodes for standard imaging. This segmentation allows independent readout paths for each pixel type, enabling parallel processing and reducing overall readout time while maintaining focus detection capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The image pickup element achieves multi-functionality by incorporating both first unit pixels (for phase difference detection) and second unit pixels (for standard imaging) within the same array. This universal design allows the device to perform both focus detection and image capture simultaneously without requiring separate dedicated sensors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If separate column output lines are provided for different pixel types, then readout time is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improvesignal readout speedVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The pixel array is divided into two distinct types: first unit pixels with M photodiodes for phase difference detection, and second unit pixels with N photodiodes for standard imaging. This segmentation allows independent readout paths for each pixel type, enabling parallel processing and reducing overall readout time while maintaining focus detection capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel array are assigned different numbers of photodiodes (M vs N) and different readout resources (first vs second column output lines). This local quality differentiation optimizes each region for its specific function while maintaining overall system efficiency and manufacturability through standardized processes.

Inventive Principle:

Principle #3Local quality

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 significantly shortens signal reading time, improves light reception characteristics, and enhances sensitivity by reducing noise, allowing for efficient simultaneous image pickup and phase difference focus detection.

Implementation Method 1

a pixel array in which a plurality of first unit pixels each including M photoelectric conversion units (M is a natural number higher than or equal to 2) and a plurality of second unit pixels each including N photoelectric conversion units (N is a natural number lower than M) are arranged in rows and columns

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS9871987B2Image pickup element and image pickup apparatus

Publication Date: 2018.01.16 CANON KK

AI summary

In an image pickup element, a plurality of unit pixels constituted by one micro lens and a photodiode arranged underneath the micro lens are arranged in rows and columns. The image pickup element includes first unit pixels in which a plurality of photodiodes are arranged underneath one micro lens, second unit pixels different from the first unit pixels, m first output lines per column from which signals of the first unit pixels are output, and n second output lines per column from which signals of the second unit pixels are output.