US 5,041,849 A · Multi-discrete-phase Fresnel acoustic lenses and their application to acoustic ink printing

Abstract

Acoustic radiators which are focused diffractively by multi-discrete-phase binary Fresnel lenses are provided for applications, such as acoustic ink printing. Standard semiconductor integrated circuit techniques are available for fabricating such lenses in compliance with design specifications having relatively tight tolerances, including specifications for integrated lens arrays demanding substantial precision in the relative spatial positioning of several lenses. The diffractive performance of these lenses simulate concave refractive lenses, even though the lenses preferably have generally flat geometries. To that end, the lenses advantageously are defined by patterning acoustically flat surfaces, such as an acoustically flat face of a substrate or, better yet, an acoustically flat face of a layer of etchable material which is grown or otherwise deposited on an acoustically flat surface of an etch resistant substrate.

Claims18

Dependent claims

An acoustic radiator for radiating an object plane to which it is acoustically coupled with focused acoustic energy;

said radiator comprising
a multi-discrete-phase Fresnel lens supported at a predetermined focal distance from said object plane, and
means acoustically coupled to said lens for illuminating it with acoustic energy;
said lens having a radial phase profile selected to diffract a substantial portion of said acoustic energy into a predetermined diffraction order at diffraction angles which vary radially of said lens, said diffraction angles being selected to cause the acoustic energy within said diffraction order to come to focus essentially on said object plane.

1 more element

An improved printhead for ejecting individual droplets of ink from a free surface of a pool of liquid ink on demand for printing images on a nearby recording medium;

said printhead comprising
an acoustically conductive substrate,
at least one multi-discrete-phase Fresnel focusing lens supported on said substrate in acoustic communication with said ink, and
means acoustically coupled to said substrate illuminating said lens with rf acoustic energy, said means including means for modulating said rf energy;
said at least one lens having a phase profile selected to diffract a substantial portion of said acoustic energy into a predetermined diffraction order at diffraction angles which vary radially of said lens, whereby said lens brings the energy it diffracts into said diffraction order to focus essentially on said free ink surface for exerting a radiation pressure against said free ink surface, with said radiation pressure being modulated in accordance with the modulation of said rf energy to eject individual droplets of ink from said free ink surface on demand at an ejection velocity sufficient to cause said droplets to deposit in an image configuration on said recording medium.

2 more elements

Dependencies are inferred from the claim text.

Multi-discrete-phase Fresnel acoustic lenses and their application to acoustic ink printing

Life of this patent

Multi-discrete-phase Fresnel acoustic lenses and their application to acoustic ink printing

Life of this patent

Abstract

Claims18