Image Pickup Element Focus Detection Pixel Electrode Arrangement

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Solution Overview

Problem

Conventional image-pickup elements face challenges in performing focus detection with high accuracy due to light transmission effects from transfer electrodes, which affect the position relationship between light shielding parts and transfer electrodes, leading to reduced light-receiving efficiency and accuracy.

Innovation Solution

The image-pickup element is configured with first and second focus detection pixels that have photoelectrical conversion parts and electrode parts arranged at opposite ends, with light shielding parts that do not overlap the transfer electrodes, allowing for reduced light transmission effects and improved light-receiving efficiency, while maintaining high accuracy in focus detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the light shielding part is formed to cover the transfer electrode, then the light transmission effect is reduced and focus detection accuracy is improved, but the sensor height increases and light-receiving efficiency decreases

Engineering Contradiction:

Improvefocus detection accuracyVSAvoidsensor height

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent extracts the light shielding function from the transfer electrode structure by providing a separate light shielding part. This allows the light shielding part to be positioned to shield the photoelectrical conversion part from light passing through the transfer electrode, while maintaining a compact sensor structure with reduced height.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The light shielding part acts as an intermediary element between the transfer electrode and the photoelectrical conversion part. It selectively blocks harmful light transmission paths while allowing necessary light to reach the photoelectrical conversion part, thereby improving focus detection accuracy without increasing sensor height.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the light shielding part is formed with sufficient thickness to block light, then light transmission through transfer electrodes is minimized, but the sensor height increases

Engineering Contradiction:

Improvelight transmission effectVSAvoidsensor height

Core Design Contradiction:

Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent converts the potentially harmful light transmission through the transfer electrode into a beneficial effect by using the transfer electrode's spectral transmission characteristics. The light shielding part is positioned to work with this existing light transmission behavior, blocking only the harmful paths while allowing useful light to pass through, thereby minimizing the light shielding part thickness and sensor height.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Use of energy by moving object

If the microlens is positioned to achieve conjugate relationship with the photoelectrical conversion part, then light-receiving efficiency is improved, but the distance from microlens to photoelectrical conversion part increases when light shielding part is added

Engineering Contradiction:

Improvelight-receiving efficiencyVSAvoiddistance from microlens to photoelectrical conversion part

Core Design Contradiction:

Use of energy by moving objectVSLength of moving object

Solution Approach 1:

The patent applies local quality by making the light shielding part's thickness and position vary locally to achieve optimal light shielding while maintaining compact overall structure. The light shielding part is positioned and dimensioned to provide sufficient shielding only where needed, allowing the microlens to maintain its optimal position for light-receiving efficiency without increasing the overall sensor height.

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 enhances focus detection accuracy and light-receiving efficiency by minimizing the impact of light transmission through transfer electrodes, ensuring precise focus detection without compromising the element's thickness or light collection capabilities.

Implementation Method 1

a photoelectrical conversion part (312) that converts light from the image-pickup lens (200) into electricity to generate an image of an object

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS8698927B2Image-pickup element, and image-pickup apparatus and camera system capable of detecting a focus state

Publication Date: 2014.04.15 CANON KK

AI summary

An image-pickup element includes an image-pickup pixel configured to photoelectrically convert light from an image-pickup lens to generate an image of an object, and a first focus detection pixel and a second focus detection pixel configured to receive light having passed through part of an area of an exit pupil of the image-pickup lens, and an electrode part of the first focus detection pixel and an electrode part of the second focus detection pixel are arranged at ends of a photoelectrical conversion part that are opposite to each other in a pupil diving direction of the first focus detection pixel and the second focus detection pixel.