Narrow aperture waveguide loudspeaker for use with flat panel display devices
A speaker having a narrow aperture waveguide for transmitting sound from the rear side of a flat display panel. A transducer of the speaker radiates sound through the waveguide and outwards from the rear of the display panel and around an edge of the display panel to form soundwaves radiating directly or nearly directly to a listener positioned in front of the display panel. The waveguide includes fins that control the directivity of soundwaves exiting the waveguide and around the edge of the display panel.
1. A speaker comprising:
a transducer;
a waveguide attached to the transducer, and having an increasing cross sectional aspect ratio and an increasing cross sectional area, both the cross sectional aspect ratio and cross sectional area increasing as the waveguide extends away from the transducer; and
an aperture portion formed with the waveguide wherein the aperture portion comprises a curved section configured to direct soundwaves around an edge of a display panel housing the speaker and substantially directly to a listener positioned in front of the display panel;
wherein the waveguide includes fins that control the directivity of soundwaves exiting the waveguide and around the edge of the display panel, and wherein the fins form a plurality of passages within the waveguide that are configured to direct the soundwaves around the edge of the display panel substantially perpendicular to a front surface of the display panel when the transducer is attached to the display panel in an outward firing configuration and the maximum wall to wall dimension within said plurality of passages formed by the fins is defined by c/f max /4, wherein c is the speed of sound and f max is an upper limit of the frequency range within which the speaker has a flat frequency response.
2. The speaker of claim 1 wherein the aperture protrudes beyond the edge of the display panel, and has an aspect ratio greater than that of the transducer, where the aspect ratio is a length of an object relative to its width.
3. The speaker of claim 1 further comprising a resonator in the transducer to minimize a resonance in the waveguide, wherein the resonator comprises one of a Helmholtz resonator or a quarter wave resonator.
4. The speaker of claim 1 wherein the fins have an increasing thickness as the waveguide extends away from the transducer.
5. The speaker of claim 1 wherein the fins comprise a fin array including a first set of fins arrayed transversely along an axis perpendicular to a longitudinal axis of the transducer, each having a first curvature corresponding to the increasing cross sectional aspect ratio of the waveguide.
6. The speaker of claim 5 wherein the fin array comprises a second set of fins arrayed longitudinally parallel to the longitudinal axis of the transducer and having a second curvature corresponding to the inclination angle of the aperture curved section.
7. The speaker of claim 1 further comprising an enclosure enclosing the transducer and at least part of the waveguide.
8. The speaker of claim 7 wherein the enclosure is configured to be mounted in a housing of the display panel to be integrated within an interior volume of the display panel with the aperture protruding beyond the edge of the display panel.
9. The speaker of claim 7 wherein the enclosure is configured to be mounted onto a back surface of the display panel to form an exterior speaker with the aperture protruding beyond the edge of the display panel.
10. The speaker of claim 7 , wherein the edge comprises a top edge of the display panel, and/or wherein the display panel comprises a display screen for use with a desktop computer viewed by a user positioned approximately two to five feet in front of the display panel, and/or wherein the enclosure is not more than one-half inch wide.
11. A method comprising:
combining a speaker having a transducer with a display panel;
providing, with the transducer, a waveguide having an increasing cross sectional aspect ratio and an increasing cross sectional area, both the cross sectional aspect ratio and cross sectional area increasing as the waveguide extends away from the transducer;
providing an aperture portion formed with the waveguide, wherein the aperture portion comprises a curved section configured to direct soundwaves around an edge of the display panel and substantially directly to a listener positioned in front of the display panel; and
forming, within the waveguide, a plurality of fins forming a plurality of passages directing the soundwaves around the edge of the display panel substantially perpendicular to a front surface of the display panel when the transducer is attached to the display panel in an outward firing configuration, wherein the maximum wall to wall dimension within said plurality of passages formed by the fins is defined by c/f max /4, wherein c is the speed of sound and f max is an upper limit of the frequency range within which the speaker has a flat frequency response.
12. The method of claim 11 wherein the speaker is provided in an enclosure attachable to a rear surface of the display panel or integrable within the display panel to become a structure formed within an interior volume of the display panel, and/or wherein the display panel is used with a desktop computer viewed by a user positioned approximately two to five feet in front of the display panel, and/or wherein the display panel is not more than one-half inch wide.
13. The method of claim 12 further comprising providing a resonator in the enclosure to minimize a resonance in the waveguide, wherein the resonator comprises one of a Helmholtz resonator or a quarter wave resonator.
14. The method of claim 11 further comprising simulating a shape of a pressure wavefront moving along the waveguide at a predetermined frequency in a zero-fin configuration and wherein forming fins comprises forming walls of the fins that are nominally perpendicular to the simulated wavefront along the length of the waveguide.
15. The method of claim 11 wherein the waveguide comprises:
a first set of fins arrayed transversely along an axis perpendicular to a longitudinal axis of the transducer, each fin of the first set of fins having a first curvature corresponding to increasing cross sectional aspect ratio of the waveguide; and
a second set of fins arrayed longitudinally parallel to the longitudinal axis of the transducer, each fin of the second set of fins having a second curvature corresponding to an inclination angle of the aperture curved section.