Ultrasonic transducer arrays and methods for the fabrication thereof
First Claim
1. A method of fabricating an ultrasonic transducer array adapter for scanning a selected object having a predetermined object wavelength comprising the steps of:
- cutting a block of piezoelectric material having a top surface in a directions perpendicular to said top surface to form a plurality of wafers, each of said wafers being of a predetermined thickness;
affixing an etchable material of predetermined depth to one side of each wafer surface except for the wafer which is to be the end wafer on the one side of the array;
forming the wafers into a spaced parallel array with each adjacent pair of wafers in the array being spaced by a layer of affixed material, the predetermined thickness for etchable material being such that the center-to-center spacing between adjacent wafers in the array is substantially equal to one-half the object wavelength; and
etching away the affixed material to leave a spaced transducer array with a substantially one-half object wavelength center-to-center spacing.
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Accused Products
Abstract
This invention provides a method for fabricating ultrasonic transducer arrays and various transducer arrays produced utilizing such methods. The method includes the steps of cutting a block of piezoelectric material to form a plurality of wafers, each wafer being of a predetermined thickness; forming the wafers into a spaced parallel array with a center-to-center spacing between the wafers substantially equal to one-half of the object wavelength (as this term is defined in the specification); and causing the space between the wafers to be filled with a substance having an acoustic impedance which differs from that of the piezoelectric material by an amount such that the reflection coefficient between the piezoelectric material and the substance is greater than 0.9. The predetermined thickness of the wafers may be equal to one-half the piezoelectric wavelength and the substance between the wafers may be formed at least mostly of air. A material of a depth substantially equal to the spacing between wafers required to achieve the desired periodicity may be affixed to one of the adjacent wafer surfaces of each space, and this material may either be etchable and etched away to form a precise air gap between the wafers, or the material may be formed in a pattern with substantially more area without material than with material. Alternatively, a material having the required acoustic impedance mismatch, and preferably also having a relatively high absorption coefficient, is placed between each two adjacent wafers when the wafers are formed into the array.
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Citations
10 Claims
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1. A method of fabricating an ultrasonic transducer array adapter for scanning a selected object having a predetermined object wavelength comprising the steps of:
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cutting a block of piezoelectric material having a top surface in a directions perpendicular to said top surface to form a plurality of wafers, each of said wafers being of a predetermined thickness; affixing an etchable material of predetermined depth to one side of each wafer surface except for the wafer which is to be the end wafer on the one side of the array; forming the wafers into a spaced parallel array with each adjacent pair of wafers in the array being spaced by a layer of affixed material, the predetermined thickness for etchable material being such that the center-to-center spacing between adjacent wafers in the array is substantially equal to one-half the object wavelength; and etching away the affixed material to leave a spaced transducer array with a substantially one-half object wavelength center-to-center spacing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification