Borosilicate Laminated Windshield for Millimeter-Wave Radar Transmission
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Solution Overview
Problem
Conventional vehicular glass configurations for millimeter-wave radar communication suffer from complex processing, reduced chipping resistance against external impacts like flying stones, and compromised radio wave transparency.
Innovation Solution
A vehicular laminated glass comprising a borosilicate glass first plate, an intermediate polyvinyl butyral film, and an alkali aluminosilicate or soda-lime glass second plate, with a total thickness of 4.0 mm or more, optimized for high radio wave transparency and strength, featuring specific glass compositions and thickness ratios to enhance chipping resistance and radio wave transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin is disposed in a part of the windshield to increase radio wave transparency, then the transparency for millimeter-wave radar waves is improved, but the windshield processing becomes complex and the strength against external impact is lowered
Solution Approach 1:
The patent changes the material parameter by using borosilicate glass with specific B2O3 content (1.0% or more in mole percentage) instead of conventional glass or resin combinations. This compositional parameter change achieves both high radio wave transparency and structural strength without requiring complex multi-layer resin structures or additional processing steps.
Solution Approach 2:
The patent employs a composite laminated glass structure consisting of borosilicate glass plates combined with intermediate films (such as polyvinyl butyral). This composite material approach integrates the radio wave transparency requirements with the mechanical strength requirements in a unified structure, avoiding the need for separate resin dispositions that would complicate processing.
2Reliability
If a resin is disposed in a part of the windshield to increase radio wave transparency, then the transparency for millimeter-wave radar waves is improved, but the chipping resistance against flying stones is lowered
Solution Approach 1:
The patent modifies the glass composition parameters by incorporating borosilicate glass with controlled B2O3 content (1.0% or more in mole percentage). This compositional change enhances both radio wave transparency and chipping resistance simultaneously, eliminating the need to use resin materials that would compromise mechanical strength.
Solution Approach 2:
The laminated glass composite structure combines borosilicate glass plates with intermediate films, creating a material system that achieves both high radio wave transparency and superior chipping resistance. The glass-to-glass composite structure with intermediate bonding provides both electromagnetic wave transmission capabilities and mechanical impact resistance.
3Strength
If the total thickness of the laminated glass is increased to improve strength, then the strength against external impact is improved, but the radio wave transmission may be affected
Solution Approach 1:
The patent optimizes the thickness parameters of individual glass plates and intermediate films within the laminated structure. By controlling the thickness of each layer and their total sum (4.0 mm or more), the design achieves both required mechanical strength and satisfactory radio wave transmission characteristics through parameter optimization rather than simple thickness increase.
Solution Approach 2:
The laminated glass composite structure allows for distributed thickness allocation across multiple layers. The combination of borosilicate glass plates with intermediate films creates a composite system where the total thickness provides mechanical strength while the specific material composition and layering maintain radio wave transmission efficiency.
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 strength against external impacts with superior radio wave transparency in high-frequency bands, ensuring effective communication while maintaining structural integrity.
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
Implementation Method 2
an intermediate film sandwiched between the first glass plate and the second glass plate
Implementation Method 3
the strength against external impact caused by flying stones or the like received during running (hereinafter referred to as 'chipping resistance' or 'strength against flying stones') is lowered
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.