Borosilicate Laminated Windshield for 79 GHz Radar Transparency
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Solution Overview
Problem
Existing vehicular glass configurations for high-frequency millimeter-wave radar communication suffer from complex processing, reduced chipping resistance against external impacts like flying stones, and compromised transparency for millimeter-wave radar waves.
Innovation Solution
A vehicular laminated glass comprising a borosilicate glass first plate, an alkali aluminosilicate or soda-lime glass second plate, and a polyvinyl butyral intermediate film, with a total thickness of 4.0 mm or more, ensuring high transmission characteristics for millimeter-wave radar waves and enhanced chipping resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin is disposed in a part of the windshield to increase transparency for millimeter-wave radar waves, then the radio wave transparency is improved, but the device complexity and manufacturing complexity increase
Solution Approach 1:
The patent changes the material composition parameters of the glass itself, specifically using borosilicate glass with controlled B2O3 content (1.0% or more in mole percentage) to achieve the desired radio wave transparency. This approach modifies the intrinsic properties of the glass material rather than adding separate resin components, thereby resolving the contradiction between improving radio wave transparency and reducing processing complexity.
2Reliability
If a resin is disposed in a part of the windshield to increase transparency for millimeter-wave radar waves, then the radio wave transparency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass material (borosilicate glass with specific B2O3 content) to achieve radio wave transparency. This material parameter change eliminates the need for complex multi-step manufacturing processes involving resin disposal, thereby improving ease of manufacture while maintaining the desired radio wave transmission characteristics.
3Device complexity
If the glass structure is simplified to reduce processing complexity, then the device complexity is reduced, but the chipping resistance against external impacts may be compromised
Solution Approach 1:
The patent employs composite material design by combining borosilicate glass (first glass plate) with specific properties (B2O3 ≥ 1.0% mole percentage) and pairing it with a second glass plate and intermediate film. This composite structure achieves both simplified processing and enhanced chipping resistance, as the borosilicate glass composition inherently provides superior mechanical strength and impact resistance while maintaining radio wave transparency.
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 provides a vehicular laminated glass that balances high radio wave transparency in high-frequency bands with improved strength and chipping resistance, simplifying the glass structure while maintaining excellent performance in millimeter-wave communication and external impact resistance.
Implementation Method 1
a transmission characteristic S21 that is obtained when TM radio waves having a frequency of 79 GHz enter the first glass plate of the vehicular laminated glass at an incident angle of 60° is −4.0 dB or larger
Data Source
AI summary
The present invention pertains to a laminated glass for a vehicle, the laminated glass including a first glass sheet, a second glass sheet and an intermediate film sandwiched between the first glass sheet and the second glass sheet, in which: the total thickness of the first glass sheet, the second glass sheet and the intermediate film is 4.0 mm or more; the first glass sheet is formed of a borosilicate glass containing, in terms of oxide by molar percentage, 1.0% or more of B2O3; and when a radio wave (TM wave) with a frequency of 79[GHz] is made incident at an incident angle of 60° to the first glass sheet, the transmission property S21 is −4.0 [dB] or more.