Ceramic PTC Heating Element for Lens Hood Defogging

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Solution Overview

Problem

Existing image acquisition devices in motor vehicles face difficulties due to fogging, freezing, or icing of the lens or viewing window, which are not efficiently addressed by current heating solutions that require high production effort and have long heating times.

Innovation Solution

A device with a ceramic PTC heating element and metallic contact parts is used, which provides rapid heating and efficient heat transfer to the lens hood, along with a heat distribution plate and various mounting options for easy assembly and reduced risk of short circuits, utilizing a composite material with inorganic particles for enhanced thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heating foil is glued to the lens hood, then the lens hood can be heated, but the production effort increases and heating time becomes long

Engineering Contradiction:
Improvelens hood temperatureVSAvoidproduction effort
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive and complex heating foil with a simple, inexpensive PTC heating element that can be easily manufactured and assembled. The PTC element is a self-regulating ceramic component that eliminates the need for complex wiring and control systems, significantly reducing production effort while maintaining effective heating capability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the heating mechanism from a passive heating foil requiring external control to an active PTC element that automatically regulates its own temperature through inherent positive temperature coefficient characteristics. This parameter change in the heating approach enables rapid heating while simplifying manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If a heating foil is glued to the lens hood, then the lens hood can be heated, but the heating time becomes long

Engineering Contradiction:
Improvelens hood temperatureVSAvoidheating time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The PTC heating element provides rapid, intense heating capability compared to the gradual heating of a heating foil. The element's high power density and direct thermal contact with the lens hood enable quick defogging or deicing, reducing the time the system needs to remain inactive due to weather conditions.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The PTC heating element can be activated immediately when needed, providing preliminary heating action before fogging or icing significantly degrades image quality. The rapid response time allows the system to prevent problematic conditions rather than merely responding to them, reducing overall heating time requirements.

Inventive Principle:
Principle #10Preliminary action

3Speed

If ceramic PTC device is used, then rapid heating is achieved, but heat distribution may be concentrated

Engineering Contradiction:
Improveheating speedVSAvoidheat distribution uniformity
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent introduces a thermally conductive adhesive as an intermediary between the PTC heating element and the lens hood. This adhesive layer acts as a heat distribution medium that spreads the concentrated heat from the small PTC element across the larger lens hood surface, maintaining rapid heating capability while achieving uniform temperature distribution.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The heating assembly becomes a composite structure combining the PTC ceramic element, thermally conductive adhesive material, and lens hood substrate. This composite approach leverages the high power density of the PTC element with the heat spreading capability of the adhesive composite, resolving the contradiction between rapid heating and uniform distribution.

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 enables quick and efficient defogging or deicing of the lens, reducing production effort and heating time, while ensuring reliable and safe electrical insulation and heat dissipation.

Implementation Method 1

After switching on, a high current flows first, which quickly leads to the heating up of the lens hood

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a metallic contact part, which is flat and well thermally conductive in a contact section connected to the PTC building block

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3451790B1Device with heated light scattering aperture
Publication Date: 2022.04.20 FRITZ EICHENAUER GMBH & CO KG
  • EP3451790B1 patent drawingFigure 1
  • EP3451790B1 patent drawingFigure 2
  • EP3451790B1 patent drawingFigure 3

AI summary

The present invention relates to a device for an image capture unit in a motor vehicle. It comprises at least one image capture unit (1), a lens hood (4), and a heating element (2) which is arranged to be thermally conductive on the lens hood (4). According to the invention, the heating element (2) has at least one ceramic PTC component (5).