Abstract: An audio system comprises an array of transparent piezoelectric transducers on a transparent surface. Each transparent piezoelectric transducer includes one or more piezoelectric layers and one or more conductive layers that are substantially transparent to visible light. A transparent piezoelectric transducer may include, e.g., a first conductive layer, a first piezoelectric layer on the first conductive layer, and a second conductive layer on the first piezoelectric layer. Or in another example, the transparent piezoelectric transducer includes many (e.g., 20-30) piezoelectric layers and many (e.g., 20-30) conductive layers.

Abstract: Systems and methods for operating a communication device. The methods comprise: immersing an antenna in an electric field of an incident radio wave; producing a net change in electrical charge on a surface of an electrodeformative element that acoustically vibrates when the antenna is immersed in the electric field of the incident radio wave; harvesting the electrical charge produced on the surface of the electrodeformative element to provide an antenna receive function; and providing the harvested electrical charge from the antenna to a receiver circuit of the communication device.

Abstract: A transducer is described that includes a substrate configured to be deposited on a solid object, and a transparent medium coupled to the substrate and configured to oscillate at a pre-selected frequency upon receipt of an electrical excitation or a mechanical excitation and to provide a first acoustic wave. The transducer also includes an actuator configured to receive an electrical power, and to provide the electrical excitation or the mechanical excitation to the transparent medium, wherein at least a portion of the solid object is viewable through the transparent medium, and the first acoustic wave is at least partially transmitted through an interface of the transparent medium. A system and a non-transitory, computer-readable medium storing instructions to cause the system to perform a method to use the transducer for generating acoustic waves in a transparent medium are also disclosed.

Abstract: A device including a body configured to be grasped by a user's hand and a touch surface oriented on a first surface of the body, wherein the touch surface is configured to be engaged by an appendage of the user's hand when the body is grasped by the user's hand. The device also includes a friction modulator associated with the touch surface, wherein the friction modulator is configured to modulate a coefficient of friction between the user's appendage and the touch surface to provide haptic feedback.

Abstract: A gear position detection device for detecting a gear having multiple fingers is provided. The detection device includes a substrate, a control chip, and a drive line, a sense line, a first drive electrode, a second drive electrode, a first sense electrode and a second sense electrode formed on the substrate. The first and second drive electrodes are connected to the drive line to receive a drive signal. The first and second sense electrodes form induced electric field respectively with the first and second drive electrodes, and respectively output a first detected signal and a second detected signal via the sense line. The control chip outputs the drive signal via the drive line, receives the first and second detected signals via the sense line, calculate a differential signal between the first and second detected signals, and count a number of high levels of the differential signal to count a finger number.

Abstract: A display device includes a display panel, an actuator unit including a plurality of actuator members generating vibrations and disposed to face one side of the display panel, and a support unit contacting the actuator unit to receive a vibration generating from the actuator unit and including a plurality of support members disposed to respectively correspond to the plurality of actuator members and spaced apart from each other.

Abstract: A switched capacitor charge pump driver for piezoelectric actuator includes a power source, a first switching capacitor and a piezoelectric actuating circuit, wherein during being at a first state, the first capacitor is charged by the power source; during being at a second state, the first capacitor is discharged to the piezoelectric actuator in the actuating circuit. The switched capacitor charge pump driver for piezoelectric actuator can expand the application of charge controller to a broader frequency range, especially at low frequencies and effectively decrease the hysteresis of piezoelectric stack over a large frequency range even at a quasistatic state. In addition, a method for driving piezoelectric actuator by a switched capacitor charge pump is provided.

Abstract: A wireless handheld communication device features a rotational navigation tool assembly such as a trackball or a thumbwheel. The rotational navigation tool assembly provides a user with tactile feedback corresponding to motion of a selection or position indicator on the device display. The tactile feedback is electromagnetically induced and may, for example, be considered an electromagnetic detent.

Abstract: The invention concerns a water resistant portable object such as a diving watch including a sound generator device (12) and a microprocessor (1), characterized in that it emits acoustic signals at two different frequencies (f1) and (f2) as a function of the medium, air or water, in which the wearer of the watch is situated.

Abstract: A piezoelectric drive device has a piezoelectric actuator that has a vibrator with a piezoelectric element, and a rotor that is rotated by the vibrator, an elastic device that can store the rotational energy of the rotor as elastic energy, and a driven body that is rotated by the elastic energy stored by the elastic device.

Abstract: A shock-activated switch device comprises a piezoelectric buzzer having a body for receiving a mechanical shock and a terminal for outputting an electrical output signal when the body receives a mechanical shock, and an output circuit connected to the terminal for converting the output signal into a logic signal for controlling an electronic circuit to execute a specific programmable function, such as alarm snooze.

Abstract: A wearable communication device includes a bone conduction actuator which is applicable for being in contact with a user's wrist, hand, back of the hand, finger or nail in order to transmit voice signals. The user inserts the user's finger into the user's ear canal, or touches the user's finger to a part near the user's ear, or puts the user's fingertip or nail on the user's ear canal so as to block the user's ear canal when the user uses the wearable communication device.

Abstract: A rectangular vibrating plate 10 in which a piezoelectric element and a reinforcing plate are stacked is supported on a main plate by a support member 11, and is urged toward the rotor 100 by an elastic force of the support member 11. This brings a projection 36 provided on the vibrating plate 10 into abutment with an outer peripheral surface of the rotor 100. In this construction, when the vibrating plate 10 vibrates in the horizontal direction in the figure by an applied voltage from a driving circuit (not shown), the rotor 100 is rotated in a clockwise direction in accordance with the displacement of the projection 36 due to the vibration.

Abstract: The present invention concerns a portable object such as, in particular, a timepiece (1), including means (16) for displaying at least one data item and a case (2) formed of a top portion including a crystal (14) covering the display means (16) and a bottom portion delimited by a back cover (6) located below said display means (16), this object including a piezoelectric transducer (32) generating an electric voltage when mechanical pressure is exerted on said top portion, the voltage generated by the piezoelectric transducer (32) being applied to a first electronic circuit which will generate a logic signal in response to the pressure exerted, this electronic circuit being arranged inside said case (2), characterized in that said piezoelectric transducer (32) is arranged in the bottom portion of said case (2) and is rigidly connected to said case (2).

Abstract: A rectangular vibrating plate 10 in which a piezoelectric element and a reinforcing plate are stacked is supported on a main plate by a support member 11, and is urged toward the rotor 100 by an elastic force of the support member 11. This brings a projection 36 provided on the vibrating plate 10 into abutment with an outer peripheral surface of the rotor 100. In this construction, when the vibrating plate 10 vibrates in the horizontal direction in the figure by an applied voltage from a driving circuit (not shown), the rotor 100 is rotated in a clockwise direction in accordance with the displacement of the projection 36 due to the vibration.

Abstract: The present invention concerns a communication system between a portable unit, such as a watch, and a communication terminal (2) such as a personal computer or PC, characterized in that the communication terminal (2) includes at least means for transmitting an acoustic signal carrying, and in that the portable unit (1) includes at least processing means for processing data, and receiving and conversion means for picking up said acoustic signal and converting said acoustic signal into data intended to be processed by said processing means.

Abstract: The present invention concerns the use of a sound generator circuit (22) including a piezoelectric vibrator (P3) as an acoustic wave receiver. The invention also concerns an electronic converter (20) including a sound generator circuit (22) provided with a piezoelectric vibrator (P3) as well as means supplying a reference voltage, characterized in that it further includes comparison means which compare the reference voltage to the voltage generated by the piezoelectric vibrator (P3) when the latter picks up an acoustic wave, said comparison means generating a pseudo-digital signal when the voltage generated by said vibrator (P3) exceeds said reference voltage. Finally the invention concerns a timepiece provided with a converter circuit (20) as described above, as well as a two-directional communication method via acoustic waves between an emitter unit and a receiver unit.

Abstract: To provide an actuator which can achieve a reduction in size and weight of a device in which the actuator is mounted by amplifying and outputting displacement of a movable end of a vibrating plate as vibration in an in-plane direction, and to provide a timepiece and a notification device using the same, in an actuator (10), when a voltage is applied to a piezoelectric element (21) formed on a vibrating plate (12), the vibrating plate (12) generates bending vibrations in an out-of-plane direction, and one end portion (125) repeats displacement in an in-plane direction as a movable end. The displacement is transmitted to a lever (32) whose base end side (321) is connected to the end portion (125) of the vibrating plate (12) and an elastically deformable constricted portion (31), and a free end (322) of the lever (32) vibrates in the in-plane direction to drive a follower member (500).

Abstract: A device includes a case (2) in which an acoustic transducer (11) is mounted so as to communicate in a water tight manner with the exterior of the case (2) via acoustic energy. The transducer (11) is mounted in front of a membrane (18) able to be deformed separating it in a water tight manner from an inlet cavity (14, 15) which is arranged in the case (2) of the device and is in communication with the exterior. Between the membrane (18) and the transducer (11) an intermediate chamber (19) is arranged allowing deformation of the membrane by the action of external static pressure and delimited on the side of the transducer by a support element (12a) fixedly mounted in the case and capable of limiting the deformation of the membrane in the event of application of the external pressure.

Abstract: A case (2) in which an acoustic transducer (22) is mounted so as to communicate in a watertight manner with the exterior of the case (2) via acoustic energy.The transducer (22) is attached to a membrane (17) separating it in a watertight manner from an inlet cavity (10, 11) which is arranged in the case (2) and is in direct communication with the exterior. The membrane (17) is resiliently applied by its periphery onto a rest surface (12) arranged around the cavity separating the latter in a watertight manner from a deformation chamber (13) situated on the side of the membrane (17) opposite to the inlet cavity while being in communication with the interior of the case. The bottom (13a) of the deformation chamber (13) forms a support surface for said membrane (17) when external static pressure greater than a predetermined value is applied thereto.

Abstract: A small electronic equipment with a vibration alarm has, as a drive source, a flat stator type bipolar stepping motor, which has a rotor having high durability, can be assembled easily, requires low power consumption, is started constantly stably, and can be rotated at a high speed. In this electronic equipment with the vibration alarm, a rotor (1) is rotated by a rotary drive system including a drive pulse generating means (112, 113, 114), a drive circuit (110), a flat stator (6), a counter electromotive voltage detection coil (306), and a magnetic pole position detection means (107, 115, 116), so that an eccentric weight (2) fixed to the rotor is rotated, thereby generating vibration. The drive pulse generating means outputs a pulse signal for driving the stepping motor on the basis of an alarm signal output at alarm time. The drive circuit supplies a drive current to a drive coil (305) on the basis of the pulse signal from the drive pulse generating means.

Abstract: A solid state alarm for a clothes dryer receives a line voltage signal prior to termination of the tumbling cycle to provide a series of pulses with decaying amplitudes driving a piezoelectric-type transducer. A timer terminating the series of pulses communicates with a pulse generating oscillator so as to eliminate partial pulsing at the conclusion of the alarm signal.

Abstract: A sound generator comprises a transducer (3) intended to be supplied with a signal having a frequency determining the sound to be produced and having a variable amplitude (envelope). To this effect, the transducer is connected in series with the principal path of a semiconductor component (5). The control electrode of this semiconductor component (5) is connected to a RC-circuit (1, 7) capable of providing control pulse trains having said envelope.The RC-circuit comprises a capacitor (7) and at least one input branch (13) of a current mirror (11) the output branch (12) of which supplies a control electrode of the semiconductor component (5). Preferably, the capacitor (7) is connected in series with the input branch (13).Application in particular to wrist-watches equipped with an audible alarm.

Abstract: The piezo-electric device (9) which connects a glass (8) to a movement (3) of the timepiece (1) is arranged in such a way as to deform in flexion in response to an exciting signal applied to its electrodes. The attachment zones (9a,9b) of this device (9) to this glass (8) and respectively to this movement (3) are distinct one from the other when the timepiece (1) is looked at in a direction perpendicular to the planes of the principal faces of the device (9). Thanks to this arrangement, the sound produced by the displacement of the glass (8) when the exciting signal is applied to the electrodes of the piezo-electric device (9) is more intense than in a known timepiece.

Abstract: An electronic device with a display having a light source, such as an electroluminescent element, becomes easier to see and is reduced in size and power consumption when a single boosting element is used for selectively driving the light source and an additional element, such as an alarm. A sound generating circuit charges and discharges with a boosted voltage a charge boosting element, such as a piezoelectric element, in accordance with a control signal supplied by an alarm signal generating circuit. A light source disable circuit discriminates when a signal is being output by an alarm signal generating circuit, and disables a boosting circuit and a discharge circuit used for driving the light source, respectively.

Abstract: A capacitive charge pump circuit and associated method is provided for outputting an output voltage which has a magnitude which is an integer multiple of the magnitude of a power supply voltage used to power the circuit. In one form, a capacitor is charged to the power supply voltage, V.sub.s. The capacitor is alternately coupled to the power supply voltage and ground so that in an alternating manner, 2 V.sub.s and -V.sub.s appear across it. By coupling a first electrode of a piezoelectric crystal to the capacitor and a second electrode of the piezoelectric crystal to the power supply voltage, a signal having a peak-to-peak magnitude which is three times that of the power supply voltage will drive the piezoelectric crystal.

Abstract: A wristwatch with an oscillation alarm uses an ultrasonic motor as its drive source. A vibration member has a piezoelectric element adhered thereto on one side and comb-like projections on the other side. A rotor has a sliding member composed of resin at its contacting portion with the comb-like projections and an eccentric weight at its outer circumferential portion. Shock absorbers are sandwiched between the weight and the rotor to absorb shocks applied to the rotor and thus prevent rotor damage. In the vicinity of the upper or lower side of the weight, there is disposed an abutment portion made of rigid material, the abutment portion abutting with the weight when shocks of large magnitude are applied to the rotor to assist the shock absorbers in preventing damage to the rotor.

Abstract: A timepiece in which a vibration member starts vibration at an alarm time to let a person know the alarm time. The timepiece comprises a case having a shape of thin, small-sized wrist watch form, timekeeping circuit for counting a present time, alarm circuit for setting alarm time, detection circuit for detecting a coincidence a present time with the alarm time and the vibration member actuated at a set time to indicate time. The vibration member comprises a ultrasonic wave motor and an eccentric weight wheel driven by the ultrasonic motor and having its center of gravity deviated from its axis. The whole timepiece is vibrated by the unbalanced centrifugal forces produced by the turn of the weight wheel at the set time to indicate the time.

Abstract: An alarm timepiece the internal movements and electronic components of which can be arranged and accommodated more efficiently in that the alarm diaphragm with a piezo-electric element attached thereto is obliquely mounted within the frame of the timepiece to lean from the bottom of the timepiece frame against a rising part of the side of the frame. This arrangement taken in conjunction with a sound emitting opening situated between the outer circumference of the bottom and the rising part of the frame of the timepiece provide an unobstructed path for the alarm sound while taking advantage of otherwise vacant space within the internal movement and electronic component compartment of the timepiece.

Abstract: A visual and audible warning device has a piezoelectric element operable to cause vibrations which are transmitted through a light transmitting member, and a light emitting element which upon actuation causes a visual warning to be transmitted through the light transmitting member. The visual and audible warnings transmitted by the light transmitting member are intended to attract the attention of the operator of a vehicle, such as a boat, above the sound of the engine or other noise. The device has circuit means coupled with the piezoelectric element and the light emitting element for causing a predetermined electrical signal to be applied to the piezoelectric element and causing energization of the light emitting element upon actuation.

Abstract: An electricity supply structure for a piezoelectric vibrator includes a circuit board and a coil spring having one end positioned in contact with the circuit board and the other end with a portion extending toward the center of the spring and a rising contact portion which stands on the extending portion at a central portion of the coil spring. A piezoelectric vibrator is in contact with the free end of the rising contact portion of the coil spring and a positioning rod for positioning the coil spring is formed integrally with the base plate and is provided at the distal portion thereof with a groove in which the extending portion is insertable to prevent radial movement of the rising contact portion relative to the piezoelectric vibrator.

Abstract: A baseball with a self-contained speed-measuring module positioned within a hollowed-out portion of the solid core of the ball, with the upper portion of the module being a display unit that indicates the speed at which the baseball was thrown over a fixed distance, the read-out of the display unit being visible from the outside to allow for the reading thereof. The module is enclosed in a single, unitary housing, and includes a computer chip. The chip includes speed-determining circuitry, and is made up of a programmable counter that counts down a plurality of times for every time interval of the flight of the thrown ball, the value representative of each time interval being loaded into the programmable counter by a programmable logic array, whose inputs are coupled to the outputs of a most-significant digit display counter of an LCD unit, the instantaneous value of which is representative of the time interval determined by the countdown rate of the programmable counter.

Abstract: A piezoelectric signaling device that produces a predetermined number of audio signals when activated. The device includes a timer, a pulser, an audio oscillator, and a piezoelectric transducer. The timer enables the pulser for a predetermined time. While enabled, the pulser produces pulses at a predetermined rate, thus producing a predetermined number of pulses. The oscillator is enabled during the pulses to produce a predetermined number of pulses of audio frequency electrical oscillations which are applied to the piezoelectric transducer to produce the predetermined number of audio signals.

Abstract: A pager is described for use in an electronic watch. The pager comprises a frame (1) for picking up a magnetic signal and a piezoelectric transducer (11) having a static capacitance on its terminals, for producing a sound. 11To improve sensitivity of reception, a switching circuit (15) connects the transducer (11) in parallel with the frame (1) to tune it by means of the static capacitance to the frequency of the magnetic signal carrier wave. To increase the performance of the transducer (11 ) when it operates as a sound transmitter, the switching circuit (15) connects the frame (1) in series with the transducer (11).

Abstract: The sound generator applies an envelope to the note signal. Current to the sound producing element is controlled by a series transistor whose base is driven with a signal having a frequency corresponding to the musical note. The driving voltage applied to the base has a voltage amplitude corresponding to the voltage stored in a capacitor connected through a resistor and discharging through said resistor and the base of the transistor controlling the current to the sound producer.

Abstract: A booster circuit in an electronic watch having: hands for indicating time or a display portion such as a panel for displaying time digitally; a lamp for lighting the display portion by electroluminescence (EL element); and a sound generating portion for generating sound at an alarm setting time by vibration of a piezo-electric element. The booster circuit has a boosting member for driving the EL element and a boosting member for driving the piezo-electric element. These boosting members commonly use one coil.

Abstract: A piezoelectric buzzer directly secured to a portion of a wrist watch casing and driven to vibrate the casing and produce an alarm sound. Associated circuitry alternately drives the piezoelectric buzzer at two different frequencies having a frequency ratio of 4:5 and at monotonically decreasing amplitudes as to produce alarm sounds like chimes.

Abstract: An electronic timepiece is provided with an alarm and means coupling a sounding unit to a circuit generating a sonic signal. The first electrode (6) of the sounding unit (5) is mechanically and electrically fixed to a metallized decoration (4) set under the glass (3). Two conductive members (12) are arranged to pass through the timepiece dial and then to be elastically supported, the first against the decoration (4) and the second against the second electrode (7) of the sounding unit in order to connect said unit to the terminals (10) of the signal generating circuit. The arrangement facilitates encasing the timepiece and thus realizes an increased productivity.

Abstract: Disclosed is a display device including a transparent piezoelectric element having transparent electrodes coated on both surfaces thereof, bonded by transparent adhesive material on an inner surface of a transparent cover to be arranged in front of a display panel of the display device. The transparent cover works as a vibration generator of a sound source. The thickness of the transparent electrodes are selected to serve as an anti-reflection layer of the near ultraviolet light. Relative dimensions of and positional relation between the transparent cover and the piezoelectric element are limited in predetermined ranges to assure high quality of display characteristic and sufficient volume of sound.

Abstract: An electro-acoustic transducer drive circuit for driving a device such as a miniature piezoelectric buzzer to emit musical notes, the notes having a damped waveform envelope whose shape is controlled by digital signals. The notes are formed by mutually independent circuit means and can be combined to produce musical chords. The circuit incorporates relatively few elements, and is suitable for implementation within a MOS IC.

Abstract: In a transducer including at least a piezoelectric ceramic plate which has curved surfaces, electrodes which are formed on both the main surfaces of the piezoelectric ceramic plate, a frame which holds the piezoelectric ceramic plate, and means for applying an electric signal to the electrodes; this invention is characterized in that the holding frame is made of an organic high-polymer resin. Since the piezoelectric ceramic plate has the curved surfaces and the holding frame is made of the organic high-polymer resin, the transducer is suitable as a loudspeaker for audio use having a wide frequency band.

Abstract: A wristwatch having a piezoelectric buzzer therein includes a watch case and a case back. The piezoelectric buzzer includes a piezoelectric element mounted on the case back inside the watch case. A driver selectively applies signals having a frequency of about 4 kHz to the buzzer. The case back, acting as the vibration plate for the piezoelectric element, is constructed so that the resonance frequency thereof is between 5.5 kHz and 7 kHz.

Abstract: A small acoustic device is provided with a housing, a first electrically actuated vibrating plate and a second vibrating plate. A support member cooperates with the housing for mounting the periphery of the second vibrating plate to the housing to define therewith an airtight chamber. The support member also supports the periphery of the first vibrating plate in the airtight chamber with a gap between the two vibrating plates and air chambers on either side of the second vibrating plate. In this way, the barometric pressure in the two air chambers on either side of the second vibrating plate are equivalent and the device is both waterproof and independent of ambient temperature changes.

Abstract: An electronic timepiece including a piezoelectric type alarm buzzer wherein the caseback functions as the buzzer diaphragm is provided. The piezoelectric element is mounted on the caseback and a battery for driving the timepiece is mounted on the piezoelectric element with an electrical insulating member therebetween for preventing short-circuiting between the battery and piezoelectric element. In an exemplary embodiment, the electrical insulating member for mounting for holding the battery is mounted to the piezoelectric element at a peripheral portion in order not to effect adversely the sound level. Alternatively, when design considerations require the battery may be mounted in a more central portion of the piezoelectric element, an angular insulating member having a central opening is used so that the insulating member contacts the piezoelectric element at the periphery thereof.

Abstract: A display device structure comprising a casing, a display panel placed in the casing, a transparent covering and vibrating plate member on the front side of the display panel and an actuator for the plate member. The covering and vibrating plate member is carried on the casing through an elastic member interposed between the peripheral portion of the plate member and the casing. By this arrangement the plate member is capable of effectively generating sound outward upon reception of vibrating force from the actuator.

Abstract: An alarm electronic wristwatch has an electromagnetic acoustic transducer having a base plate having a plurality of upstanding projections, and a lead substrate superposed on the base plate and having a plurality of openings dimensioned to receive respective ones of the projections. The cooperation between the projections and openings enable precise positioning of the lead substrate on the base plate. The lead substrate has a set of cut-out or recessed portions in which are mounted permanent magnets. A magnetic core and excitation coil are mounted on the base plate and the terminals of the excitation coil are connected to an electrode pattern formed on the upper surface of the lead substrate. The lead substrate extends laterally of the transducer to enable electrical connection to a circuit block of the wristwatch from which drive signals may be applied to the excitation coil.

Abstract: Disclosed is a transparent piezoelectric transducer comprising, at least, a transparent vibrator and at least one plate of a piezoelectric ceramic material sandwiched between a pair of transparent electrodes, said transparent vibrator being disposed so as to be vibrated by the piezoelectric ceramic material plate, said piezoelectric ceramic material being a ceramic material which is represented by a formula:Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.z).sub.1-x/4 0.sub.3where x and y/z are set within a region enclosed with lines successively coupling points a-b-c-d-e-a in a phase diagram (FIG. 2 of the accompanying drawings) in which a ratio (y/z) between PbZrO.sub.3 and PbTiO.sub.3 is taken on an axis of abscissas, while an La concentration (x) is taken on an axis of ordinates (where x=8.4 and y/z=65/35 at a, x=6 and y/z=55.5/44.5 at b, x=6 and y/z=50/50 at c, x=12 and y/z=50/50 at d, and x=9 and y/z=65/35 at e). The transparent transducer is excellent in both the transparency and the electroacoustic response.

Abstract: A thin timepiece comprising a flattened casing, a display unit, a diaphragm having its peripheral portion carried by the casing to generate sound, a piezoelectric element mounted on the diaphragm and a module for driving the display unit and the piezoelectric element. The diaphragm and the piezoelectric element are formed ring-like so that the space in the central hole of the ring-like diaphragm and piezoelectric element is used for a part of the occupation space of the electric cell in the casing and that renewal of an electric cell is facilitated by the provision of the space for the cell in the diaphragm and the piezoelectric element.

Abstract: In an electronic clock circuit having both a stepper motor and a PXE (piezoelectric oxide) alarm element, the stepper motor and PXE element are connected in parallel and appropriate motor and PXE drive signals are provided on the same line. With this circuit configuration, an inductance and a transistor are eliminated from the prior art circuit, thus resulting in a smaller and less expensive device.

Abstract: This invention intends to provide a speaker which assumes a comparatively large area in a device without spoiling various display effects. The transparent flat panel speaker of this invention is a speaker of high efficiency which can give forth a sound volume large considering the small-sized device even when driven by a low voltage.The transparent flat panel speaker of this invention comprises, at least, a transparent resonator plate and a plate of a piezoelectric material held between at least one pair of electrodes, the resonator being excited by the piezoelectric material plate, a periphery of the resonator plate having a shape which is represented by a curve or in which straight lines are connected by smooth curves with at least two centers of curvature.As the peripheral shapes, an ellipse, a curve expressed by X.sup.n /a+Y.sup.n /b=1, a plane figure obtained by molding the corners of a polygon circumscribed or inscribed to an ellipse, etc. are especially favorable for the speaker.