Apparatus for and method of converting from a digital signal to an acoustic wave using a piezoelectric beam

Claim 3

The apparatus according to claim 1, wherein the digital word includes a polarity bit location and the converting means further includes means for converting the magnitude bits into one of a plurality of voltages having a first and a second level in response to the state of the polarity bit location to cause the free end of the beam to deflect in any one of the two directions.

Claim 4

The apparatus according to claim 1, wherein the voltage representative of the most significant bit is applied across the element of the beam closest to the fixed end and the voltage representative of the least significant bit is applied across the element of the beam closest to the free end, the beam elements having substantially equal surface areas.

Claim 5

The apparatus according to claim 1, wherein the voltages have an absolute magnitude greater than zero volts and wherein the applying means includes a first layer of a grounded conductive material on a first surface of the beam and a second layer of a conductive material on a second surface of the beam, the second layer being divided into a plurality of electrically separated segments, each of which is connected to one of the voltage outputs of the converting means.

Claim 6

The apparatus according to claim 4, wherein the beam is made of lead zirconate titanate.

Claim 7

An electroacoustic transducer for converting a serial digital word, of the type having a plurality of bit locations including locations for a polarity bit and a plurality of magnitude bits having at least a most and a least significant bit, into an acoustic signal, the transducer being adapted to convert digitized audio in a time division multiplexed format into an audio acoustic signal comprising: a. means for converting the serial digital word into parallel form, b. buffer means for converting each magnitude bit into an output voltage of a first polarity when a bit is present in the polarity bit location and for converting each magnitude bit into an output voltage of a second polarity when a bit is absent from the polarity bit location, c. a piezoelectric structure including a beam made of a piezoelectric, non-conductive material and having fixed and free ends and first and second side surfaces, a first layer of a grounded conductive material on the first surface of the beam and a second layer of conductive material on the second surface of the beam, the second layer being divided into a plurality of electrically separated segments having substantially equal surface areas, each segment being connected to an output of the buffer means with the segment closest to the fixed end being connected to the output corresponding to the most significant bit and the segment closest to the free end being connected to the output corresponding to the least significant bit, the beam being adapted to have its free end deflected in a direction corresponding to the polarity of the word and at a magnitude corresponding to the magnitude of the word and, d. acoustic means connected to the free end for creating an acoustic signal in response to the deflection of the free end of the piezoelectric beam.

Claim 8

An electroacoustic transducer for converting a serial digital word, of the type having a plurality of bit locations including locations for a polarity bit and a plurality of magnitude bits having at least a most and a least significant bit, into an acoustic signal, the transducer being adapted to convert digitized audio in a time division multiplexed format into an audio acoustic signal comprising: a. means for converting the serial digital word into parallel form, b. buffer means for converting each magnitude bit into an output voltage of a first polarity when a bit is present in the polarity bit location and for converting each magnitude bit into an output voltage of a second polarity when a bit is absent from the polarity bit location, c. a piezoelectric structure including a beam made of a piezoelectric, non-conductive material and having fixed and free ends and first and second side surfaces, a first layer of a grounded conductive material on the first surface of the beam and a second layer of conductive material on the second surface of the beam, the second layer being divided into a plurality of electrically separated segments having substantially equal surface areas, each segment being connected to an output of the buffer means with the segment closest to the fixed end being connected to the output corresponding to the most significant bit and the segment closest to the free end being connected to the output corresponding to the least significant bit, the beam being adapted to have its free end deflected in a direction corresponding to the polarity of the word and at a magnitude corresponding to the magnitude of the word and, d. acoustic means connected to the free end for creating an acoustic signal in response to the deflection of the free end of the piezoelectric beam.

Claim 9

The transducer according to claim 6, wherein the buffer means includes a first and second plurality of gating means for controlling the application of the voltages of the first and second polarities, respectively, to the segments of the beam, each of the first gating means being enabled by the presence of a polarity bit and by the presence of a respective magnitude bit, each of the second gate means being enabled by the absence of a polarity bit and by the presence of a respective magnitude bit.

Claim 10

The transducer according to claim 6, wherein the piezoelectric material is lead zirconate titanate.

Claim 11

The transducer according to claim 7, wherein the gating means include AND logic gates.

Claim 12

The transducer according to claim 6, wherein the acoustic means includes a speaker cone connected to the free end of the beam so that the speaker cone generates acoustic signals in response to the sequence of deflections of the free end of the beam.

Claim 13

The transducer according to claim 6, wherein the converting means includes a serial to parallel shift register.

Claim 16

The method according to claim 12, further including the step of applying the voltage representative of the most significant bit across the segment closest to the fixed end, and applying the voltage representation of the least significant bit across the segment closest to the free end of the beam, the segments having substantially equal surface areas.

Claim 17

The method according to claim 12, wherein the digital word includes a polarity bit and wherein the step of applying the voltages includes the steps of forming a first and second plurality of voltages of different levels in response to the state of the polarity bit to cause the beam to deflect in one of two directions depending on the polarity of the digital word.