US 6,320,989 B1 · Stepped acoustic impedance-matching transformer for very narrow channel acoustic traveling wave lens waveguide

Abstract

An acoustic impedance-matching transformer includes a tapered acoustic energy transmission (metal) block, having an acoustic impedance less than that of a piezo-electric transducer in a metric direction toward that of the acoustic propagation medium of the waveguide, and by an amount that allows tailoring of the relative spatial dimensions of mating surfaces of the transducer and the block, so as to provide efficient broadband coupling of acoustic energy. The surface area of the end face of the block engaging the transducer is a corresponding fraction of the area of the transducer. The tapered block focuses acoustic energy toward the input aperture of the waveguide channel. The taper is determined in accordance with difference between the acoustic impedance of the aluminum block and that of a second acoustic wave propagation element, such as a quarter-wave section of plexiglass, interposed between the waveguide channel and the tapered block.

Claims29

Dependent claims

An arrangement for launching an acoustic wave into a narrow channel waveguide of an acousto-optic scanner, said narrow channel waveguide containing an acoustic wave propagation medium, upon which a scanned optical beam to be modulated by said acoustic wave traveling through said narrow channel waveguide is incident, said narrow channel waveguide having opposing first and second ends, said arrangement comprising:

an acoustic transducer having a first acoustic impedance for generating an acoustic wave in response to the application of an electrical drive signal thereto;
and
an acoustic impedance transformer having a first end coupled to and of a different size than a first end of said acoustic transducer, and a second end coupled to an acoustic input aperture of said narrow channel waveguide, and wherein said acoustic impedance transformer is physically configured to effectively match an acoustic impedance of said acoustic transducer with an acoustic impedance of said acoustic wave propagation medium of said narrow channel waveguide.

A method for acousto-optic scanning using an acousto-optic scanner comprising an acoustic transducer, a narrow channel waveguide, an acoustic wave propagation medium in the narrow channel waveguide, and an optical beam generator for generating an optical beam through the acoustic wave propagation medium, the method comprising:

effectively matching an impedance of the acoustic transducer with an impedance of the acoustic wave propagation medium by connecting an acoustic impedance transformer therebetween, the acoustic impedance transformer being physically configured to effectively match the impedances and having a first end coupled to and of a different size than a first surface of the acoustic transducer and a second end coupled to an acoustic input aperture of the narrow channel waveguide;
and
launching an acoustic wave from the acoustic transducer through the acoustic impedance transformer and into the narrow channel waveguide while the optical beam passes therethrough to thereby perform acousto-optic scanning.

Dependencies are inferred from the claim text.

Stepped acoustic impedance-matching transformer for very narrow channel acoustic traveling wave lens waveguide

Life of this patent

Stepped acoustic impedance-matching transformer for very narrow channel acoustic traveling wave lens waveguide

Life of this patent

Abstract

Claims29