Active Pixel Sensor Shared Output Circuit Topology

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Solution Overview

Problem

Conventional CMOS image sensors face reduced light transmission and sensing accuracy due to the presence of metal wires, which affects the size of sensing elements and disperses light, degrading the overall sensing performance.

Innovation Solution

The active pixel sensor design includes a substrate with sensing circuits and output circuits arranged in a specific configuration, where sensing circuits are placed on pixel rows excluding a specific row, and output circuits are placed on that specific row, reducing the number of metal wires and enhancing light transmission by sharing output circuits among sensing circuits on the same column.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If sensing element size is reduced to increase pixel density, then the number of pixels increases, but light transmission is reduced and sensing accuracy degrades

Engineering Contradiction:

Improvenumber of pixelsVSAvoidsensing accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

Multiple sensing circuits sharing a common output circuit and floating diffusion node, reducing redundant components and metal wire connections

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared output circuit and floating diffusion node serve multiple sensing circuits simultaneously, enabling one component to perform multiple functions

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If metal wires are added to connect pixels, then circuit connectivity is achieved, but light transmission is blocked and dispersion occurs

Engineering Contradiction:

Improvecircuit connectivityVSAvoidlight transmission

Core Design Contradiction:

Ease of operationVSIllumination intensity

Solution Approach 1:

Multiple sensing circuits share common output circuits and floating diffusion nodes, reducing the total number of metal wire connections required

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The harmful metal wire connections are minimized by extracting the common functions to shared output circuits, removing unnecessary light-blocking elements

Inventive Principle:

Principle #2Taking out (Extraction)

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 reduces the number of horizontal lines on the sensor substrate, thereby increasing optical transmission and improving sensing accuracy by minimizing light dispersion and enhancing the fill rate of each pixel.

Implementation Method 1

Each of the plurality of sensing circuits comprises a sensing element, a transfer transistor, and a floating diffusion node

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10455179B2Active pixel sensor with sensing circuits and output circuits disposed on the same substrate

Publication Date: 2019.10.22 SILICON OPTRONICS

AI summary

An active pixel sensor is provided. The active pixel sensor includes a substrate, a plurality of sensing circuits, and a plurality of output circuits. The substrate is divided into a plurality of pixel rows. A plurality of pixel areas are disposed on the plurality of pixel rows. The plurality of sensing circuits are disposed in the pixel areas on the pixel rows excluding a specific pixel row among the plurality of pixel rows. The plurality of sensing circuits are further disposed on a plurality of pixel columns to form an array. Each of the plurality of sensing circuits includes a sensing element, a transfer transistor, and a floating diffusion node. The plurality of output circuits are disposed in the pixel areas on the specific pixel row. The sensing circuits on the same pixel column are coupled to the same output circuit.