Pixel-Level Defect Correction in Photoelectric Conversion Devices

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Solution Overview

Problem

Existing photoelectric conversion devices lack the capability to detect and correct defective pixels, which can lead to anomalies in output values, as they do not perform individual pixel corrections.

Innovation Solution

A photoelectric conversion device with a plurality of pixels arranged in rows and columns, each equipped with a light receiving unit and a signal generation unit that includes a count unit and a comparison unit. The comparison unit compares the count value of pulses from the light receiving unit with a threshold value, allowing for the detection and correction of defective pixels by replacing the count signal with a substitute signal when the count value exceeds the threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a correction unit is added to perform correction on output values, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvepixel output accuracyVSAvoidcorrection unit structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The correction function is segmented and distributed to individual pixel circuits rather than using a separate correction unit. Each pixel circuit independently performs correction operations on its own output signal, eliminating the need for a centralized correction device and reducing overall system complexity while maintaining correction capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each pixel circuit performs self-correction by comparing its own count value with a reference value and automatically adjusting its output signal accordingly. This self-service approach eliminates the need for external correction units and enables each pixel to independently compensate for defects or anomalies

Inventive Principle:

Principle #25Self-service

2Measurement precision

If individual pixel correction is implemented, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvedefective pixel detection accuracyVSAvoidpixel circuit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pixel circuit is designed to perform multiple functions including photon counting, value comparison, and correction operations within a single integrated circuit. This multi-functionality eliminates the need for separate correction units and enables each pixel to independently detect and correct defects while maintaining a compact structure

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a comparison unit is added to each pixel to compare count values with threshold, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improvedefective pixel detection capabilityVSAvoidsignal generation unit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The signal generation unit is designed to perform multiple functions including counting photons, comparing count values with reference values, and generating corrected output signals within a single integrated circuit. This multi-functionality eliminates the need for separate correction units and enables each pixel to independently detect and correct defects while maintaining a compact structure

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The comparison function is merged into the signal generation unit of each pixel circuit, combining counting, comparison, and correction operations in a single integrated structure. This merging approach improves reliability by enabling real-time defect detection at the pixel level while avoiding the complexity of separate correction units

Inventive Principle:

Principle #5Merging (Combining)

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

Enables the detection and correction of defective pixels, ensuring accurate output values and improving the overall quality of the image captured by the device.

Implementation Method 1

a light receiving unit that outputs a pulse in response to incidence of a photon

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS11069823B2Photoelectric conversion device, photoelectric conversion system, and movable object comprising a comparison unit to compare the count value of pulse with a predetermined threshold value

Publication Date: 2021.07.20 CANON KK

AI summary

A photoelectric conversion device includes a plurality of pixels arranged in a plurality of rows and a plurality of columns, and a plurality of output lines to which signals from the plurality of pixels are output, and each of the plurality of pixels includes a light receiving unit that outputs a pulse in response to incidence of a photon and a signal generation unit that, based on output from the light receiving unit, generates a pixel signal output to each of the output lines. The signal generation unit includes a count unit that generates a count signal indicating a count value of pulses output from the light receiving unit and a comparison unit that compares the count value indicated by the count signal with a predetermined threshold value, and the signal generation unit outputs a signal in accordance with a result of comparison performed by the comparison unit.