Annular Light-Shielding Member for Condensation Prevention in Dome Cameras

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Solution Overview

Problem

Surveillance cameras with illumination units face challenges in air circulation, leading to condensation and frost on dome-shaped covers, which degrade image sharpness, especially in low-temperature environments, due to the close contact of light-shielding members with the cover surfaces hindering air circulation.

Innovation Solution

An image pickup apparatus with an annular light-shielding member that has groove or hole formations allowing air circulation while maintaining light imperviousness, preventing condensation and frost on the dome cover surfaces by enabling airflow through spiral, crank, or linear designs that absorb or reflect illumination light effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an annular light-shielding member is placed in close contact with the inner wall of the dome-shaped cover to prevent illumination light reflection, then light shielding performance is improved, but air circulation is hindered leading to condensation and frost formation

Engineering Contradiction:
Improvelight shielding performanceVSAvoidcondensation and frost formation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The light-shielding member is designed with numerous through-holes that allow air to pass through while maintaining light blocking functionality. The holes enable air circulation between the front space and inner space of the dome-shaped cover, preventing condensation and frost formation on the cover surfaces while the light-shielding material itself maintains its light-blocking properties.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The light-shielding member is segmented into multiple sections with through-holes distributed across its surface. This segmentation allows the structure to simultaneously perform light shielding and air circulation functions, dividing the member into light-blocking regions and air-passages regions that work together to resolve the contradiction.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a sealed structure is adopted for the surveillance camera, then protection performance is improved, but air circulation is insufficient causing condensation and frost on dome surfaces

Engineering Contradiction:
Improveprotection performanceVSAvoidcondensation and frost on dome surfaces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The light-shielding member with through-holes acts as a porous structure that allows controlled air circulation within the sealed camera body. This enables moisture evacuation and temperature equalization while maintaining the overall sealed protection of the camera against external environmental factors.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The light-shielding member serves as an intermediary structure between the sealed interior and the dome-shaped cover. It provides a pathway for air circulation while maintaining the sealed structure's protection performance, acting as a mediator that allows necessary air flow without compromising the sealed enclosure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If air circulation paths are provided within the lens unit, then condensation prevention is improved, but device complexity increases

Engineering Contradiction:
Improvecondensation preventionVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The air circulation function is merged with the light-shielding member structure. The through-holes in the light-shielding member simultaneously serve light blocking and air circulation purposes, eliminating the need for separate air circulation paths and reducing overall device complexity while effectively preventing condensation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light-shielding member is designed with multi-functionality, serving both as a light-blocking component and an air circulation pathway. This universal design allows a single structure to perform multiple functions, reducing the number of components needed and simplifying the overall device structure while maintaining effective condensation prevention.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Improved air circulation within the apparatus prevents condensation and frost on the dome cover surfaces, ensuring high-sharpness images while maintaining light shielding, thus enhancing the performance of surveillance cameras in various environmental conditions.

Implementation Method 1

shield reflected light of illumination light so as to prevent the illumination light from being reflected by the cover and entering the lens unit

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

shield reflected light of illumination light so as to prevent the illumination light from being reflected by the cover and entering the lens unit

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

causing air to circulate in the surveillance camera through natural convection using a permeable film or a dehumidification element provided inside the surveillance camera

Methodology Applied
Scientific EffectNatural convection: Free Convection

Data Source

PatentEP3244602B1Image pickup apparatus such as network camera, and image monitoring system
Publication Date: 2023.01.11 CANON KK
  • EP3244602B1 patent drawingFigure 1A~1B
  • EP3244602B1 patent drawingFigure 2
  • EP3244602B1 patent drawingFigure 3

AI summary

An image pickup apparatus which is able to obtain images with high sharpness by improving circulation of air in the image pickup apparatus to prevent formation of condensation and frost on a cover (101), which protects a lens unit (201), while ensuring imperviousness to light. An illumination unit (206a) provided around a lens unit (201) emits illumination light toward a subject through the cover (101) placed on a subject side of the lens unit (201). An annular light-shielding member (203) between the lens unit and the cover (101) prevents the illumination light from reflecting on the cover (101) to enter the lens unit (201) and shields reflected light of the illumination light. The light-shielding member (203) has a circulation path that enables circulation of air between a space on the subject side of the lens unit (201) and on an inner peripheral side of the light-shielding member (203) and a space on an outer peripheral side of the light-shielding member (203).