Vocab Ch 3 Flashcards
Axial Resolution
the minimum reflector separation along the sound path that is required to produce separate echoes (to distinguish between reflectors.) AR (mm)=SPL (mm) / 2
Lateral Resolution
the minimum reflector separation perpendicular to the sound path that is required to produce separate echoes. LR(mm)= Beam width (mm)
Piezoelectricity
conversion of pressure to electric voltage.
Curie Point
the temperature at which an element material loses its piezoelectric properties.
Damping Material
a mixture of a plastic or epoxy resin attached to the rear face of the transducer element.
Matching Layer
a material attached to the front face of a transducer element to reduce the reflections at the transducer surface.
Coupling Medium
a gel used to provide a good sound path between a transducer and the skin by eliminating the air in between the two.
Sound Beam
the region of a medium that contains virtually all of the sound produced by a transducer.
Side Lobes
weaker beams of sound traveling out of a single element in directions different from those of the primary beam.
Aperture
size of a transducer element (for a single-element transducer) or a group of elements (for an array).
Near Zone Length (NZL, Fresnel Zone)
the region of a sound in which the beam diameter decreases as the distance from the transducer increases.
Far Zone Length (Fraunhover Zone)
the region of a sound in which the beam diameter increases as the distance from the transducer increases.
Natural Focus
the narrowing of a sound beam that occurs with an unfocused flat transducer element.
Array
a transducer assembly containing several piezoelectric elements.
Lens
a curved material that focuses a sound or light beam.