Image Sensor With Integrated Infrared Cut-Off Filter for Day/Night Switching

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Solution Overview

Problem

Current image capture systems with switchable infrared cut-off filters experience momentary interruptions and image degradation due to periodic ambient light testing, leading to over or underexposed images when brightness changes significantly between tests.

Innovation Solution

An imaging system with an integrated infrared cut-off filter and reserved pixels, allowing continuous light intensity monitoring without interrupting image capture, and switching between day and night modes based on real-time visible light intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a switchable infrared cut-off filter is used to improve image quality during the day, then image quality is improved, but momentary interruptions and image degradation occur due to periodic ambient light testing

Engineering Contradiction:

Improveimage qualityVSAvoidimage capture continuity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The image sensor is divided into two functional regions: image recording pixels for capturing images and reserved pixels for monitoring ambient light intensity. This segmentation allows continuous light monitoring without interrupting image capture, as the reserved pixels continuously measure ambient light while the image recording pixels continuously capture images, eliminating the need to interrupt imaging for filter switching decisions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Reserved pixels act as intermediary sensors that continuously monitor ambient light intensity and provide data to the electronic processor. This intermediary measurement system enables real-time detection of brightness changes without requiring the infrared cut-off filter to physically move or interrupt image capture, thus maintaining both image quality and capture continuity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If periodic ambient light testing is performed to determine filter engagement, then infrared filtering control is achieved, but image degradation occurs when brightness changes significantly between tests

Engineering Contradiction:

Improveinfrared filtering controlVSAvoidimage exposure quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The reserved pixels continuously monitor ambient light intensity without interruption, providing a continuous stream of brightness data to the electronic processor. This continuous monitoring enables real-time detection of brightness changes and immediate adjustment of infrared cut-off filter engagement, ensuring images are never degraded by delayed response to lighting changes.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The reserved pixels provide continuous feedback about ambient light intensity to the electronic processor, which uses this feedback to determine when to engage or disengage the infrared cut-off filter. This feedback mechanism ensures the filter is always in the correct state for current lighting conditions, preventing overexposure or underexposure even when brightness changes rapidly.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the infrared cut-off filter is moved to cover or uncover the image sensor, then day and night mode switching is achieved, but image capture is momentarily interrupted

Engineering Contradiction:

Improveday and night mode switchingVSAvoidimage capture rate

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The reserved pixels continuously monitor ambient light intensity in advance, allowing the electronic processor to predict when mode switching will be needed and prepare accordingly. This preliminary detection enables smooth, planned transitions between day and night modes without sudden interruptions to image capture, as the filter can be positioned in advance of actual lighting changes.

Inventive Principle:

Principle #10Preliminary action

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

Ensures high-quality image capture by continuously adapting to ambient light conditions, preventing image degradation and maintaining consistent image quality during mode transitions.

Implementation Method 1

A subset of the plurality of reserved pixels are covered by an infrared cut-off filter

Methodology Applied

Scientific EffectInfrared filtering: Absorption (EM radiation)

Data Source

PatentUS12464207B2Image sensor with an integrated infrared cut-off filter

Publication Date: 2025.11.04 MOTOROLA SOLUTIONS INC

AI summary

Imaging systems with an integrated infrared cut off filter and methods for operating same. One example system includes an image sensor and an electronic processor coupled to the image sensor. The image sensor includes a plurality of image recording pixels and a plurality of reserved pixels. A subset of the plurality of reserved pixels are covered by an infrared cut-off filter. The electronic processor is configured to determine a first visible light intensity for the subset of the plurality of reserved pixels. The electronic processor is further configured to control the image sensor to operate in one of a day mode and a night mode based on the first visible light intensity.