Abstract: A piezoelectric acoustic device comprises: at least two piezoelectric actuators; a support body that supports the at least two piezoelectric actuators; and a signal input unit that drives the at least two piezoelectric actuators at respective arbitrary times. At least one pair of piezoelectric actuators among the at least two piezoelectric actuators is arranged in such a manner that their sound radiation surfaces face each other with a predetermined gap.

Abstract: Piezoelectric actuator (51) includes a piezoelectric element (11) that performs expansion/contraction movement in accordance with the state of an electrical field, a base (21) with the piezoelectric element (11) adhered to one surface thereof, and a support member (46) for supporting the piezoelectric element (11) and the base (21), the piezoelectric element (11) and base (21) vibrating up and down in accordance with the expansion/contraction movement of the piezoelectric element (11). The base (21) is connected to the support member (46) by way of a vibration film (31) having less rigidity than the base (21). In addition, the piezoelectric element (11) and support member (46) have different outline shapes.

Abstract: An electronic device includes a microphone, a microphone holder holding the microphone therein, and a case encasing the microphone holder therein. The microphone holder has a first portion at which the microphone holder makes contact with a first inner surface of the case, and a second portion at which the microphone holder makes contact with one of a part of the electronic device and a second inner surface of the case facing the first inner surface, the microphone holder being sandwiched between the first inner surface and the part. At least one of the first and second portions of the microphone holder is disposed more outwardly than an outer edge of the microphone in a plane which is in parallel with the first inner surface.

Abstract: A piezoelectric acoustic element 1 of the present invention comprising a hollow casing 5 having a opening 3, a piezoelectric element 7 that is disposed in said casing 5 and bends when a voltage is applied thereto, and diaphragm 8 provided at the opening 3 of said casing 5; wherein said piezoelectric element 7 and said diaphragm 8 are joined through a vibration transmitting member 9.

Abstract: A piezoelectric acoustic device comprises: at least two piezoelectric actuators; a support body that supports the at least two piezoelectric actuators; and a signal input unit that drives the at least two piezoelectric actuators at respective arbitrary times. At least one pair of piezoelectric actuators among the at least two piezoelectric actuators is arranged in such a manner that their sound radiation surfaces face each other with a predetermined gap.

Abstract: A piezo-electric actuator comprising: piezo-electric element 1a having piezo-electric body 3a which is provided with at least two opposing surfaces, wherein the surfaces perform an expanding and contracting motion in accordance with the state of an electric field; a constraint member 21a for constraining piezo-electric element 1a on at least one of the two surfaces, a supporting member disposed around constraint member 21a, and a plurality of beam members 22a each having both ends fixed to constraint member 21a and supporting member 4a, respectively, wherein each beam member has a neutral axis for bending in a direction substantially parallel with the constrained surface, wherein the constraint member vibrates by vibration which is generated by the constraining effect between the constraint member and the piezo-electric element, and is amplified by the beam members.

Abstract: Piezoelectric actuator (51) includes a piezoelectric element (11) that performs expansion/contraction movement in accordance with the state of an electrical field, a base (21) with the piezoelectric element (11) adhered to one surface thereof, and a support member (46) for supporting the piezoelectric element (11) and the base (21), the piezoelectric element (11) and base (21) vibrating up and down in accordance with the expansion/contraction movement of the piezoelectric element (11). The base (21) is connected to the support member (46) by way of a vibration film (31) having less rigidity than the base (21). In addition, the piezoelectric element (11) and support member (46) have different outline shapes.

Abstract: A piezoelectric actuator capable of providing high sound pressure and excellent frequency characteristics when it is used as an acoustic element and advantageous for a reduction in size. The piezoelectric actuator (50) comprises a piezoelectric element (10) performing such an expansion/contraction motion that its principal plane is expanded or contracted according to the state of a filed, a pedestal (24) on which the piezoelectric element is stamped, and four beam parts (30) connected to the outer peripheral parts of the pedestal (24). The pedestal (vibrating part) is vertically vibrated according to the expansion/contraction motion of the piezoelectric element (10). Each of the beam parts (30) comprises an extension part (35) extending from the outer peripheral part of the pedestal (24) to the outside and a rise part (36) continuously extended from the extension part (35) in a direction perpendicular to the extended direction of the extension part (35).

Abstract: A piezoelectric acoustic element 1 of the present invention comprising a hollow casing 5 having a opening 3, a piezoelectric element 7 that is disposed in said casing 5 and bends when a voltage is applied thereto, and diaphragm 8 provided at the opening 3 of said casing 5; wherein said piezoelectric element 7 and said diaphragm 8 are joined through a vibration transmitting member 9.

Abstract: A piezo-electric actuator is provided which is capable of providing large vibration amplitude, is adjustable for resonance frequency, and has high reliability while avoiding an increase in outer dimensions.

Abstract: An electronic device includes a microphone, a microphone holder holding the microphone therein, and a case encasing the microphone holder therein. The microphone holder has a first portion at which the microphone holder makes contact with a first inner surface of the case, and a second portion at which the microphone holder makes contact with one of a part of the electronic device and a second inner surface of the case facing the first inner surface, the microphone holder being sandwiched between the first inner surface and the part. At least one of the first and second portions of the microphone holder is disposed more outwardly than an outer edge of the microphone in a plane which is in parallel with the first inner surface.

Abstract: A signal compression/expansion device has a frequency band division circuit, a compression/expansion circuit and a band synthesis circuit. The frequency band division circuit divides an input signal into a plurality of frequency bands. The compression/expansion circuit compresses/expands the input signal in accordance with a level of the input signal with a predetermined gain. The frequency band synthesis circuit adds the plurality of input signals having being compressed/expanded.

Abstract: This invention has been made to provide a speaker system capable of miniaturization and presenting a good sound quality. A speaker 15 is mounted on a printed circuit board 21 arranged inside a telephone body enclosure 12. Acoustic waves of positive phase produced by vibration of a diaphragm 23 of the speaker 15 are output through front acoustic apertures 28 and a front air chamber 37 to the exterior from an enclosure acoustic aperture 13. On the other hand, the acoustic waves of opposite phase enter a rear air chamber 35 through rear acoustic apertures 29, reach an enclosure internal space 36 through an opposite-phase opening 34 provided by cutting away a part of a rear sealing member 32, and transmit to a card slot 14, then being output to the exterior.

Abstract: A foldable handy phone of the present invention includes a receiver case and a transmitter case hinged to each other. A piezoelectric device or similar sounding means is accommodated in the receiver case. A through hole is formed in the surface of the receiver case that faces the transmitter case when the handy phone is folded up. The through hole is communicated to a portion accommodating the sounding means. A groove is formed in the above surface of the receiver case and extends from the open end of the through hole to the end of the receiver case opposite to the end hinged to the transmitter case. When the sounding means produces an alert tone in the folded position of the handy phone, the alert tone is radiated to the outside via the groove.

Abstract: This invention has been made to provide a speaker system capable of miniaturization and presenting a good sound quality. A speaker 15 is mounted on a printed circuit board 21 arranged inside a telephone body enclosure 12. Acoustic waves of positive phase produced by vibration of a diaphragm 23 of the speaker 15 are output through front acoustic apertures 28 and a front air chamber 37 to the exterior from an enclosure acoustic aperture 13. On the other hand, the acoustic waves of opposite phase enter a rear air chamber 35 through rear acoustic apertures 29, reach an enclosure internal space 36 through an opposite-phase opening 34 provided by cutting away a part of a rear sealing member 32, and transmit to a card slot 14, then being output to the exterior.

Abstract: Disclosed is a piezoelectric diaphragm with a transparent piezoelectric member and a transparent electrode. Also disclosed is a portable electronic device that has a display means to display an image and a piezoelectric speaker having a transparent piezoelectric member and a transparent electrode. In this portable electronic device, the piezoelectric speaker is disposed in front of the display means.

Abstract: Apparatus for detecting the opening and closing angle which is easy to switch, is reliable, is capable of positively preventing howling from occurring, can be reduced in size and weight, and uses no special components. The apparatus comprises a first and second hinge portions belonging to a first and second housings, respectively, for pivotal linking said first housing to said second housing. The first hinge portion has on the lateral side a curved surface in a rotational direction of said first housing and comprises a given number of parallel electrodes extending in a rotational direction of said first housing on said convex curved surface. The curved surface portion is disposed in the second housing; the second housing includes therein terminals in pressure contact with said electrodes or the curved surface; the terminals are in contact or non-contact with corresponding electrodes at different predetermined angles depending on the rotation of the first housing.

Abstract: A server stores media data excluding a data portion which is the same as sample data being a part of the media data, as distribution data to be distributed. A reproduction terminal stores the sample data. The reproduction terminal downloads predetermined distribution data from the server through a network, in accordance with the operation of a user. The reproduction terminal generates the media data from the sample data which is provided in advance and the downloaded distribution data, thereby reproducing the media data. The reproduction terminal reproduces the generated media data.

Abstract: An educational system server connected to a network comprises a student database for storing student ID, proficiency level, status of payment of tuition and the like of students. The educational system server checks the ability level of the student based on data of the student stored in the student database and, based on the results, selects a course suitable for the student. Further, a next course step suitable for the student is selected according to the current proficiency level of the student. Finally, whether or not the course is to be completed is judged based on the results of grading. By virtue of this constitution, an educational system can be realized wherein a student can select a course, which matches the current proficiency level of the student, and, during taking of the course, can change the course level and can cancel the course.

Abstract: A D/A converter realizes an output analog signal with less ripple within a wide range and includes (a) a bit recognizer for recognizing at least one bit of a digital input signal to thereby produce a pulse width signal and a control signal; (b) a PWM signal generator for generating a PWM signal with a variable pulse width according to a value of the input signal by modulating the input signal according to a PWM process; and (c) an output circuit for outputting an output pulse voltage according to the value of the input signal. The pulse width of the PWM signal is controlled by the pulse width signal, and the output pulse voltage is controlled by the control signal. The pulse width of the PWM signal and the output pulse voltage are controlled in such a way that an area of a pulse of the PWM signal is equal to an area of every other pulse. Each pulse of the PWM signal may be divided into blocks having different values designed for forming a specific expansion characteristic.