Composite wall, notably motor vehicle windshield, including an ultrasonic device for detecting the presence of foreign bodies on one of its faces
First Claim
1. A composite wall comprising a first sheet having a first thickness, a second sheet having a second thickness, said sheets being separated by an intermediate layer having a third thickness, and an ultrasonic detection device cooperating with an external face of said second sheet to detect the presence of foreign bodies on an external face of said first sheet, said detection device comprising transducer means able to emit an incidental ultrasonic signal of frequency f, said transducer means also being able to receive an ultrasonic signal reflected on said face of said first sheet representative of the presence or absence of said foreign bodies, said intermediate layer comprising, at least facing the transducer means, a recess in which is placed an inserted element having two opposite faces respectively in close contact with the first and second sheets, said frequency f of the transducer means satisfying the following relationships:
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space="preserve" listing-type="equation">f≈
K.sub.1.V.sub.1 /2e.sub.1 ≈
K.sub.2.V.sub.2 /2e.sub.2 ≈
K.sub.3.V.sub.3 /2e.sub.3where K1, K2 and K3 are defined integers, e1, e2 and e3 are respectively the thickness of the first sheet, the thickness of the second sheet and the thickness of the inserted element, and V1, V2 and V3 are respectively the propagation speeds of an ultrasonic wave in the first sheet, in the second sheet and in the inserted element.
1 Assignment
0 Petitions
Accused Products
Abstract
The composite wall comprises a first sheet and second sheet separated by an intermediate layer as well as an ultrasonic detection device placed on a face of said second sheet and comprising a transducer element able to emit an incidental ultrasonic signal of frequence f, and able to receive an ultrasonic signal reflected on a face of said first sheet. The intermediate layer comprises at least facing the transducer element, an inserted element whose two faces are respectively in close contact with the first and second sheets. Further, the frequence f of the transducer element satisfies the following relationships:
f≈K.sub.1. V.sub.1 /2e.sub.1 ≈K.sub.2.V.sub.2 /2e.sub.2
≈K3.V3 /2e3
where K1, K2 and K3 are defined integers, e1, e2 and e3 are respectively the thickness of the first sheet, the second sheet and the inserted element, and V1, V2 and V3 are respectively the propagation speeds of an ultrasonic wave in the first sheet, in the second sheet and in the inserted element.
12 Citations
20 Claims
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1. A composite wall comprising a first sheet having a first thickness, a second sheet having a second thickness, said sheets being separated by an intermediate layer having a third thickness, and an ultrasonic detection device cooperating with an external face of said second sheet to detect the presence of foreign bodies on an external face of said first sheet, said detection device comprising transducer means able to emit an incidental ultrasonic signal of frequency f, said transducer means also being able to receive an ultrasonic signal reflected on said face of said first sheet representative of the presence or absence of said foreign bodies, said intermediate layer comprising, at least facing the transducer means, a recess in which is placed an inserted element having two opposite faces respectively in close contact with the first and second sheets, said frequency f of the transducer means satisfying the following relationships:
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space="preserve" listing-type="equation">f≈
K.sub.1.V.sub.1 /2e.sub.1 ≈
K.sub.2.V.sub.2 /2e.sub.2 ≈
K.sub.3.V.sub.3 /2e.sub.3where K1, K2 and K3 are defined integers, e1, e2 and e3 are respectively the thickness of the first sheet, the thickness of the second sheet and the thickness of the inserted element, and V1, V2 and V3 are respectively the propagation speeds of an ultrasonic wave in the first sheet, in the second sheet and in the inserted element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification