Dome Camera Light Shielding for Low Light Reflections

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Solution Overview

Problem

Dome cameras face challenges in low light conditions due to internal reflections and size constraints when integrating infrared lighting, leading to compromised image quality and a bulky system.

Innovation Solution

A compact dome camera design with a light shielding element and a light absorbing agent in the dome-shaped cover, separating the optical and light emitting elements to prevent reflections and improve low light performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If an IR lamp is mounted inside the dome camera, then low light performance is improved, but internal reflections in the dome cover deteriorate image quality

Engineering Contradiction:
Improvelow light performanceVSAvoidinternal reflections
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

A light shielding element is introduced as an intermediary component between the light emitting element and the lens. This element includes a light absorbing portion that contacts the inner surface of the dome-shaped cover, acting as a mediator to prevent harmful light reflections from reaching the lens while allowing the IR lamp to remain inside the dome for low light illumination.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dome-shaped cover is designed with non-uniform optical properties: a first portion (where the light shielding element contacts) contains a light absorbing agent to prevent reflections, while a second portion (opposite the light emitting element) maintains high light transmission for imaging. This local differentiation resolves the contradiction between preventing reflections and maintaining image quality.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If an external IR lamp is used with the dome camera, then low light performance is improved, but the system becomes bulky and non-compact

Engineering Contradiction:
Improvelow light performanceVSAvoidsystem compactness
Core Design Contradiction:
Illumination intensityVSVolume of moving object

Solution Approach 1:

The light emitting element is merged with the dome camera system by mounting it inside the dome-shaped cover rather than using an external lamp. The light shielding element is integrated into the dome structure, allowing the IR illumination function to be combined with the dome camera in a compact configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light emitting element is nested inside the dome-shaped cover, and the light shielding element is nested within the space between the light emitting element and the lens. This nested arrangement allows multiple components to occupy overlapping spatial volumes, achieving compactness while maintaining functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If a light shielding element is added to prevent internal reflections, then image quality is improved, but device complexity increases

Engineering Contradiction:
Improveinternal reflectionsVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The light shielding element is implemented as a thin, flexible component that can be made of elastomeric material. This thin-film approach prevents internal reflections without adding significant bulk or complexity to the dome camera structure.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The light shielding element combines different materials with complementary properties: an elastomeric base material providing flexibility and mounting capability, and a light absorbing agent (such as carbon black or metal particles) dispersed within it to prevent light reflections. This composite structure achieves the light shielding function efficiently.

Inventive Principle:
Principle #40Composite materials

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

The solution enhances low light performance while maintaining a compact form by reducing internal reflections and light leakage, achieving improved image quality without the bulkiness of external IR lamps.

Implementation Method 1

the portion of the dome-shaped cover where the light shielding element abuts the inwardly facing surface of the dome-shaped cover is made of a material comprising a light absorbing agent which absorbs light in a wavelength range corresponding to light emitted by the light emitting element

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a light shielding element arranged between the optical member and the light emitting element in the space so as to shield the lens of the optical member from light emitted by the light emitting element

Methodology Applied
Scientific EffectLight shielding: Absorption (EM radiation)

Data Source

PatentEP2685310B1Dome camera for low light conditions
Publication Date: 2017.12.13 AXIS
  • EP2685310B1 patent drawingFigure 1~2
  • EP2685310B1 patent drawingFigure 3
  • EP2685310B1 patent drawingFigure 4

AI summary

There is provided a compact dome camera (1) suitable for operation under low light conditions. The dome camera (1) comprises an optical member (4) comprising a lens (10) and a light emitting element (5) arranged at a distance from the optical member (4) in a space (7) formed by a dome-shaped cover (3) and a base member (2) of the dome camera (1). A light shielding element (6) is arranged between the optical member (4) and the light emitting element (5) so as to shield the lens (10) of the optical member (4) from light emitted by the light emitting element (5). At least a portion of the dome-shaped cover (3) is made of a material comprising a light absorbing agent which absorbs light in a wavelength range corresponding to light emitted by said light emitting element (5).