Apparatus with directivity pattern
View Patent ↗A loudspeaker is described. The loudspeaker includes two or more segmentations of a planar radiator. Each of the segmentations has an associated frequency dependent velocity magnitude and phase with substantially uniform surface pressure. The two or more segmentations provide a substantially uniform radiation pattern across a wide range of acoustic frequencies. Apparatus, computer readable media and methods are also described.
1. An apparatus comprising:
a plurality of segmentations of a planar radiator,
wherein each segmentation of the plurality of segmentations has an associated frequency dependent velocity magnitude and phase with substantially uniform surface pressure and provides a substantially uniform radiation pattern across a range of acoustic frequencies, and wherein the plurality of segmentations comprise:
a plurality of axially symmetric concentric rings of electrode pairs having a membrane disposed between members of each electrode pair, each member of electrode pairs being driven by a respective bridge amplifier having anti-phase outputs.
2. The apparatus of claim 1 , wherein an input electric signal is amplified by a first bridge amplifier and applied to a centermost electrode pair, and wherein each successive bridge amplifier is coupled to an output of a phase delay element of a plurality of serially connected phase delay elements, such that the input electric signal is delayed from the centermost electrode pair towards an electrode pair disposed at a periphery of the concentric rings of electrode pairs.
3. The apparatus of claim 1 , wherein the plurality of bridge amplifiers and phase delay elements are embodied in at least one integrated circuit chip or module.
4. The apparatus of claim 1 , embodied as an electret loudspeaker, wherein the membrane contains a polarizing charge.
5. The apparatus of claim 1 , embodied as an electrostatic loudspeaker, wherein the membrane comprises a conductive coating connected to a voltage source.
6. The apparatus of claim 1 , wherein the apparatus is embodied in a dipole loudspeaker.
7. The apparatus of claim 1 , wherein the segmentations are one of: striped, circular, elliptical, rectangular and square in shape.
8. The apparatus of claim 1 , embodied as one of: an electret, an electrostatic, an electrodynamic and a piezoelectric loudspeaker.
9. The apparatus of claim 1 , wherein the plurality of segmentations comprise at least three segmentations and the width of each of the at least three segmentations is less than a wavelength of the acoustic frequencies.
10. The apparatus of claim 1 , wherein the acoustic frequencies are within a frequency range of 150 Hz to 20 kHz.
11. An apparatus comprising:
a plurality of segmentations of a planar radiator,
wherein each segmentation of the plurality of segmentations has an associated frequency dependent velocity magnitude and phase with substantially uniform surface pressure and provides a substantially uniform radiation pattern across a range of acoustic frequencies,
wherein the plurality of segmentations comprise a plurality of concentric rings of electrode pairs having a membrane disposed between members of each electrode pair, and
further comprising at least one amplifier configured to drive each member of an electrode pair, and a plurality of phase delay elements,
wherein an electric signal applied to each of the electrode pairs is delayed from the centermost electrode pair towards an electrode pair disposed at a periphery of the concentric rings of electrode pairs.
12. The apparatus of claim 11 , wherein there is a multi-way cross-over network comprising the plurality of phase delay elements connected between an output of an amplifier and the concentric rings of electrode pairs.
13. The apparatus of claim 11 , wherein the rings are one of circular, or elliptical, or rectangular, or square in shape.
14. The apparatus of claim 11 , embodied as an electret loudspeaker, wherein the membrane contains a polarizing charge.
15. The apparatus of claim 11 , embodied as an electrostatic loudspeaker, wherein the membrane comprises a conductive coating connected to a voltage source.
16. The apparatus of claim 11 , embodied in one of: a dipole loudspeaker and a monopole loudspeaker.
17. The apparatus of claim 11 , embodied as one of: an electret, an electrostatic, an electrodynamic and a piezoelectric loudspeaker.
18. A method comprising:
providing a loudspeaker having an segmentation of a planar radiator,
wherein each segmentation is configured to exhibit an associated frequency dependent velocity magnitude and phase with substantially uniform surface pressure and to provide a substantially uniform radiation pattern across a range of acoustic frequencies,
wherein the segmentation is comprised of a plurality of concentric rings of electrode pairs having a membrane disposed between members of each electrode pair; and
exciting each member of an electrode pair with an electric signal that is applied to each the electrode pairs,
wherein exciting comprises delaying the electric signal from a centermost electrode pair towards an electrode pair disposed at a periphery of the concentric rings of electrode pairs.
19. The method of claim 18 , wherein the rings are one of circular, or elliptical, or rectangular, or square in shape.