Planar Heating Element Wire Configuration for Windshield Detection
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Solution Overview
Problem
The accuracy of specifying the range heated by planar heating elements in vehicle windshield devices is inadequate, leading to errors in detecting objects like dew, frost, and ice, which affects the detection of other vehicles and obstacles.
Innovation Solution
A planar heating element with a heating wire folded to cover a plane surrounded by a contour line and a conductive wire with lower electrical resistivity than the heating wire, positioned outside the plane, is used. This configuration, combined with an insulation film and a planar good thermal conductor, enhances temperature distribution uniformity and accuracy in heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the conductive wire has the same electrical resistivity as the heating wire, then the structure is simpler, but the temperature distribution uniformity deteriorates
Solution Approach 1:
The patent applies different electrical resistivity properties to different parts of the wire structure. The heating wire has higher electrical resistivity to generate heat, while the conductive wire has lower electrical resistivity to conduct current efficiently. This local differentiation of material properties optimizes both heating performance and current conduction, resolving the contradiction between temperature uniformity and structural simplicity.
2Area of stationary object
If the heating wire covers a larger area, then the heating range is increased, but the accuracy of specifying the heated range deteriorates
Solution Approach 1:
The wire structure is segmented into two distinct functional components: the heating wire that generates heat and covers the required area, and the conductive wire that precisely defines the boundary. This segmentation allows the heating area to be expanded while maintaining accurate specification of the heated range through the contour-following conductive wire.
3Manufacturing precision
If the conductive wire follows the contour line outside the plane, then the heated range accuracy is improved, but the current supply distance increases
Solution Approach 1:
The conductive wire acts as an intermediary element that follows the contour line to precisely define the heated range boundary. Although this increases the current supply distance, it is necessary to achieve accurate heated range specification. The lower electrical resistivity of the conductive wire compensates for the increased length, maintaining efficient current conduction.
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 effectively limits the collection of objects by precisely defining the heated range, improving the uniformity and accuracy of temperature distribution, thereby enhancing the detection capabilities of the vehicle windshield device.
Implementation Method 1
a heating wire that is repeatedly folded in a manner covering a plane surrounded by a contour line... when current flows to the conductive wire and the heating wire
Implementation Method 2
a planar good thermal conductor that covers at least part of the current-carrying portion with the insulation film located between the planar good thermal conductor and the current-carrying portion... the uniformity of the temperature distribution of the planar heating element is increased
Data Source
AI summary
Provided are a planar heat generating body and a vehicle windshield device that are capable of effectively suppressing adhesion of foreign matter thereto. The planar heat generating body includes: a heat generating wire that repeatedly folds so as to cover a surface surrounded by an outline; and a conducting wire for supplying current to the heat generating wire, that has a lower electrical resistance than the heat generating wire, as a result of having a greater width than the heat generating wire, and follows the outline.