JP2015195419A - Electroacoustic conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker capable of flexibly utilizing a plurality of magnetic circuits in an electroacoustic conversion device such as e.g., a speaker that can be thinned.SOLUTION: A speaker 10 includes: magnet plates 31 and 32 including a magnetized surface 33 on which multi-pole magnetization has been performed; and a vibration film 50 that is disposed to face the magnetized surface 33 while holding buffering materials 41 and 42 therebetween. The vibration film 50 includes a wiring pattern 60 including a plurality of independent wiring 61a-61c to which different electric signals are applied. The wiring pattern 60 includes an array pattern 65 that is an array pattern extending along a magnetization boundary 36 of the magnetization surface on which multi-pole magnetization has been performed, and is made symmetrical with the magnetization boundary as a center.

Description

  The present invention relates to an electroacoustic transducer including a speaker and a microphone.

  Patent Document 1 discloses a digital sound that is optimal for a digital speaker device that directly converts analog sound by a circuit that outputs a plurality of digital signals by a ΔΣ modulator and a mismatch shaping filter circuit and a plurality of speakers driven by the plurality of digital signals. A system is proposed. Patent Document 1 includes a ΔΣ modulator, a post filter, s drive circuits, and a power circuit that supplies power to the ΔΣ modulator, the post filter, and s drive elements. The digital speaker driving device is characterized in that the driving circuit corresponds to s number of digital signal terminals.

  Patent Document 2 discloses a thin full-surface driving speaker having a high-density pattern having a full-range acoustic conversion capability and a driving method with a high degree of freedom in frontal shape design while realizing a thinning that can be built into a small flat-screen television or the like. Is provided. The speaker described in Patent Document 2 has first and second magnetic circuits each having the same configuration of a magnetic circuit that forms a maximum number of circular magnetic gaps arranged at high density on almost the entire surface of a yoke plate forming a frame. The magnetic circuit groups are arranged on both sides of the diaphragm so that each of the magnetic circuits faces each other with the same polar surface at an interval, and the voice coil carried by the diaphragm is a circular magnet of each of the two groups of magnetic circuits facing each other. Arranged perpendicularly to the magnetic flux direction in the main magnetic flux loop formed in a continuous pattern of the maximum effective line length that traces all of the gap with a single stroke and formed radially on the neutral surface between the opposing magnetic circuits with respect to the circular magnetic gap Is done. The yoke plate includes a through hole that radiates sound pressure in a wide amplitude region due to vibration of the diaphragm to the outside.

JP 2010-28785 A JP 2011-250063 A

  There is a need for an electroacoustic transducer that can flexibly use a plurality of magnetic circuits in a thinned electroacoustic transducer such as a speaker.

  One embodiment of the present invention is an electroacoustic transducer including a magnet plate including a magnetized surface that is multipolarly magnetized, and a vibration film that is disposed so as to face the magnetized surface with a buffer material interposed therebetween. The vibration film includes a wiring pattern including a plurality of independent wirings to which different electric signals are applied, and the wiring pattern is an array pattern extending along the magnetization boundary of the multipolar magnetized surface, It includes a symmetrical arrangement pattern centered on the magnetization boundary.

  This electroacoustic transducer is a surface-type electroacoustic transducer in which a magnet plate and a diaphragm are arranged to face each other, and a plurality of magnetic circuits are provided by a plurality of independent wirings to which different electrical signals are applied. Can be configured. Furthermore, by including a symmetrical arrangement pattern around the magnetization boundary along the magnetization boundary in the wiring pattern, vibration is efficiently generated by the force component parallel to the vibration film when multiple magnetic circuits are configured. Can cancel well.

  Therefore, in this electroacoustic transducer, the functions of a plurality of magnetic circuits each constituted by a plurality of wirings can be flexibly selected or reconfigured. For example, by supplying different drive signals to a plurality of wirings included in the wiring pattern, the function as a plurality of speakers can be realized by a single surface type (flat type, flat plate type) device. Further, by connecting a plurality of wirings included in the wiring pattern in an appropriate combination, it is possible to function as one or a plurality of speakers having different characteristics.

  In this electroacoustic transducer, it is desirable that the arrangement order of the plurality of wires included in the array pattern along the adjacent magnetization boundary is reversed. Even in the case where different electrical signals with a biased pattern are applied to each of the plurality of wirings, the vibration can be canceled efficiently by the force component parallel to the vibration film. Therefore, the vibration film can be efficiently vibrated in the direction perpendicular to the surface of the vibration film.

  It is desirable that the vibration film includes a wiring pattern on both surfaces, and more magnetic circuits can be configured as one vibration film. A typical magnetized surface is multipolarly magnetized in a stripe shape, and a typical one of a plurality of wiring patterns provided on the vibration film is arranged (arranged) in a stripe shape. Typically, a quadrangular magnet plate is multipolarly magnetized at equal pitches in stripes parallel to either side, and the wiring pattern of the diaphragm is parallel to any side of the diaphragm. The arrangement pattern is arranged at the same pitch as that of the multipolar magnetization.

  The electroacoustic transducer has a connection piece integrated with the vibrating membrane, and the connection piece preferably includes a plurality of connection ends that electrically connect each of the plurality of wirings and the external wiring. A combination of a plurality of wirings can be controlled using a plurality of connection ends, and can be used as an electroacoustic transducer having different characteristics.

  The electroacoustic transducer preferably includes a connection unit that switches an electrical signal input or output to each of the plurality of wirings via a plurality of connection ends in units of clocks. Even if each of the plurality of wirings included in the wiring pattern has the same basic characteristics, fine acoustic characteristics are often different due to manufacturing tolerances. Therefore, by switching the allocation of the plurality of wirings in units of clocks, the acoustic characteristics of the plurality of wirings included in the wiring pattern can be averaged, and an electroacoustic transducer with better acoustic characteristics can be provided.

  The electroacoustic transducer preferably includes a substrate integrated with the vibration film and a processing unit that is mounted on the substrate and supplies a digital acoustic signal to each of the plurality of wirings. By integrating the substrate on which the processing unit is mounted and the vibration film, the processing unit and the plurality of wirings can be connected without using a terminal. For this reason, a space-saving and lightweight electroacoustic transducer including a processing unit can be provided.

  In the electroacoustic transducer, it is effective to provide a slit along the boundary between the vibration film and the substrate. Easy to control vibration characteristics of diaphragm. Further, the processing unit preferably includes a connection function for switching the digital acoustic signal supplied to each of the plurality of wiring patterns in units of clocks.

  One of the different forms of the present invention is a speaker having the above-described electroacoustic transducer and a housing that houses the electroacoustic transducer.

The figure which shows the external appearance of a speaker. The figure which expands and shows the structure of a speaker. The figure which shows the structure of the front and back of a diaphragm. Sectional drawing which shows arrangement | positioning of wiring. The block diagram of a terminal unit. The figure which shows the printed wiring board containing a vibration film. The figure explaining digitization. The figure which shows a mode that a digital signal is divided | segmented into each wiring. The figure which shows the signal supplied to each wiring.

  FIG. 1 shows the appearance of a flat speaker as an example of the electroacoustic transducer according to the present invention. FIG. 2 is a development view showing a schematic configuration of the flat speaker 10. The speaker 10 includes a plate-shaped housing 20, plate-shaped magnet plates 31 and 32 disposed on the upper and lower sides (front and rear, or left and right) of the housing 20, and buffer plates (buffer members) 41 on the magnet plates 31 and 32. And 42 and a terminal unit 70 for connecting the vibration film 50 and external wiring.

  The housing 20 is made of metal, plastic, or wood, and may be made of other materials such as ceramic and glass. The housing 20 includes an upper housing 21 and a lower housing 22, each having a plurality of openings 23. The shape of the opening 23 is not limited to a circle, and may be a polygon, a net, a slit, or the like. The housing 20 may constitute the speaker 10 alone, or may be a part of a television, a personal computer, other electrical products, or furniture. Further, the housing 20 may be a part of the interior of the vehicle or the interior of the room, and the housing 20 may be a part of other movable property or real estate.

  The magnet plates 31 and 32 housed inside the housing 20 are permanent magnet plates having a common configuration, and the striped N pole 35n and S pole 35s are parallel stripes on the front and back magnetized surfaces 33 by magnetization. Appear alternately. Further, a plurality of through holes 34 are provided along a boundary (magnetization boundary) 36 of the belt-like N pole 35n and S pole 35s (hereinafter, sometimes referred to as a magnetized region 35 regardless of the pole). .

  The magnet plates 31 and 32 may be a sintered magnet plate, a non-sintered magnet plate, a flexible magnet plate, a solid-structure magnet plate, or any other known magnet plate. The material to which magnetism is added may be a ferrite magnet, a rare earth magnet, a neodymium-iron-boron magnet, or the like. The thickness and shape of the magnetic plate 31 (square, rectangular, circular, elliptical, etc.) and structure (whether it is a single permanent magnet plate or a structure in which a plurality of permanent magnet plates are bonded together) are arbitrary. Depending on the design problem, it can be appropriately selected according to the characteristics, cost, manufacturing necessity, use condition, and the like. Further, the size of the magnetic pole (magnetization size), the pole pitch, etc. are arbitrary, and can be selected based on factors such as the size of the housing 20 and the required volume.

  Hereinafter, the speaker 10 having a structure in which the vibration film 50 is sandwiched between the two magnet plates 31 and 32 will be described as an example. However, even if the vibration film 50 is disposed only on one side (one side) of one magnet plate. In addition, the vibration film 50 may be disposed on both sides of one magnet plate, or a structure in which a plurality of magnet plates and vibration films are stacked may be employed.

  The buffer members 41 and 42 disposed between the magnet plates 31 and 32 and the vibration film 50 are soft, have air permeability that allows sound waves to freely pass through, and are approximately the same size as the vibration film 50. Shaped member. One example of the buffer members 41 and 42 is a laminate of a plurality of thin sheet-like nonwoven fabrics (about 2 to 5 sheets). When the buffer members 41 and 42 are formed by stacking a plurality of sheet-like members, it is desirable to arrange them so that they can be individually vibrated (displaced) without being bonded. The buffer members 41 and 42 prevent the vibration film 50 from hitting the magnet plates 31 and 32 and generating abnormal noise (noise that is not normal vibration sound) during operation, and prevent the vibration film 50 itself from generating divided vibrations (chattering). This includes controlling the generation of sound other than sound waves that are faithful to the sound source.

  The vibration film 50 is a thin resin film. For example, a polyimide film (aromatic polyimide film), a polyethylene terephthalate film, or the like can be used, and the thickness is preferably about 10-50 μm, more preferably about 20-40 μm. The vibration film 50 may be a laminate of a plurality of films. The vibrating membrane 50 of this example is a rectangular portion of a resin film (printed wiring board) 59 that is square (rectangular) and has a small connecting piece 58 provided on one side. A plurality of wiring patterns 60 are formed on both surfaces 51 and 52 on the vibration film 50.

  FIGS. 3A and 3B show both surfaces (upper surface and lower surface, front surface and rear surface, front surface and back surface) 51 and 52 of the vibration membrane 50. For reference, the arrangement of the magnetized regions 35n and 35s of the magnetized surface 33 of the opposing magnet plate 30 is shown.

  A wiring pattern 60 including three wirings 61 a, 61 b and 61 c is formed on the surface 51 of the vibration film 50. On the back surface 52 of the vibration film 50, a wiring pattern 60 including three wirings 61 d, 61 e and 61 f and having the same or symmetrical arrangement as the wiring pattern on the front surface 51 is formed. Further, the connection piece 58 integrated with the vibrating membrane 50 is provided with connection terminals 62 connected to both ends of the respective wirings 61a to 61c and 61d to 61f. Therefore, the front and back wirings 61a to 61f are electrically independent, and different electrical signals can be applied to the wirings 61a to 61f via the connection terminals 62, respectively. The wirings 61a to 61f and the connection terminals 62 are printed wirings, and the resin film 59 including the vibration film 50 is a flexible type printed wiring board. These wirings 61a to 61f can be formed by photoetching a flexible copper-clad print film. Since the configuration of the front surface 51 and the back surface 52 is common, the wiring pattern 60 on the front surface 51 will be described below.

  The vibration film 50 includes a wiring pattern 60 including a plurality of independent wirings 61a to 61c to which different electric signals are applied. The wiring pattern 60 is arranged on the edge side of the vibration film 50 in a direction perpendicular to the magnetization boundary 36 and the first arrangement pattern 65 extending along the magnetization boundary 36 of the magnetized surface 33 magnetized with multipoles. An extended second array pattern 66. In the first arrangement pattern 65, a plurality of wirings 61a to 61c are arranged at symmetrical positions with the magnetization boundary 36 as the center. That is, since the first array pattern 65 includes three wirings 61a to 61c, the wiring 61b is disposed along the magnetization boundary 36, and the wirings 61a and 61c are disposed in parallel to the wiring 61b at equal intervals. ing.

  The adjacent first array patterns 65 are connected by the second array pattern 66, and the order of the wirings 61 a to 61 c is reversed by the second array pattern 66. Therefore, in the adjacent first arrangement pattern 65, the arrangement order of the wirings 61a to 61c is reversed.

  FIG. 4 schematically shows a state in which the diaphragm 50 is sandwiched between the upper and lower magnet plates 31 and 32 in the speaker 10 by a cross-sectional view. The buffer member is omitted. Magnetized regions 35 (35n and 35s) magnetized in stripes appear on the surfaces (magnetized surfaces) 33 of the magnet plates 31 and 32. The perpendicular magnetic field component (absolute value) of the magnetized region 35 is the largest in the vicinity of the centers of the magnetized regions 35n and 35s, and the boundary between the magnetized regions 35n (N pole) and 35s (S pole) (magnetized boundary). ) It is the smallest in the vicinity of 36. This is because the magnetization magnetic field component is defined in the vertical direction. Since there is no vertical component magnetic field in the vicinity of the boundary 36, this region is sometimes referred to as a neutral zone. On the other hand, the horizontal component (component parallel to the surface of the permanent magnet plate) of the magnetic field 37 formed by these magnetized regions 35 is the smallest in the vicinity of the centers of the respective magnetized regions 35n and 35s, and in the vicinity of the magnetized boundary 36. Is the largest. This is because the lines of magnetic force 37 pass in an arc from the adjacent magnetized region 35n (N pole) to the magnetized region 35s (S pole).

  When an electric current is passed through the wirings 61 a to 61 c of the vibration film 50, a force that moves the vibration film 50 according to the direction of the magnetic field 37 works according to Fleming's left-hand rule. The horizontal component of the magnetic field 37 is a component that contributes to vibrating the vibrating membrane 50 in the thickness direction. By applying a signal (current) to the wirings 61a to 61c, the vibrating membrane 50 is vibrated in the thickness direction and converted into sound. it can. Therefore, the wirings 61 a to 61 c are arranged along the magnetization boundary 36 having the largest horizontal component by the first arrangement pattern 65. On the other hand, the first array pattern 65 includes a plurality of wirings 61a to 61c. Therefore, a plurality of wirings 61 a to 61 c are arranged with a certain width in a direction perpendicular to the magnetization boundary 36. For this reason, when a current flows through the wirings 61a and 61c on both sides, it acts not only on the horizontal component of the magnetic field 37 but also on the vertical component, and moves the vibrating membrane 50 in the thickness direction (vertical direction in this figure). There is a possibility that a force to move in a parallel direction (horizontal direction in this figure) works.

  In the first arrangement pattern 65 provided in the vibration film 50 of this example, the wirings 61 a and 61 c on both sides are arranged at positions symmetrical with respect to the magnetization boundary 36. Therefore, when a signal having the same phase is supplied to the wirings 61a and 61c on both sides, the force in the reverse direction in the direction parallel to the vibrating membrane 50 (horizontal direction) in the wirings 61a and 61c on both sides due to the vertical component of the magnetic field 37. Will occur. Therefore, the force that moves the vibrating membrane 50 generated by the wirings 61a and 61c in the horizontal direction is canceled, and the vibrating membrane 50 can be vibrated up and down in a stable state to generate sound.

  Different electrical signals can be independently supplied to the wirings 61a to 61c. Therefore, the same electrical signal is not always supplied to the wirings 61a and 61c on both sides. However, when the wirings 61a to 61c are used as a sound source, the signal strengths supplied to the wirings 61a to 61c are often substantially equal on a time average. Furthermore, as will be described below, the terminal unit 70 is provided with a function of selecting and connecting the wirings 61a to 61c randomly or cyclically in units of clocks, thereby reducing the signal strength supplied to the wirings 61a to 61c. Further averaging is possible.

  Further, in the adjacent first array pattern 65, the order of the wirings 61a to 61c is reversed. In the adjacent first array pattern 65, the direction of the current flowing through each of the wirings 61a to 61c is reversed. Therefore, in the same wiring, for example, the wiring 61c, the direction of the vertical component of the magnetic field 37 is the same and the direction of the current is reversed. For this reason, the force that moves the vibrating membrane 50 generated by the wires 61 a and 61 c in the horizontal direction is canceled between the adjacent first arrangement patterns 65. Therefore, even when electrical signals having different phases or electrical signals having different polarities are supplied to the wirings 61a to 61c, the vibration film 50 is vibrated up and down in a stable state, and the electrical signals are converted into acoustic signals. Can be converted to output.

  The acoustic signal output by the vibrating membrane 50 is output to the outside through the through holes (through portions) 34 provided in the magnet plates 31 and 32. Further, the movement of the vibration film 50 and the buffer members 41 and 42 in the horizontal direction (direction parallel to the surface) can be restricted by providing the housing 20 with an appropriate stopper structure. For example, the movement of the diaphragm 50 or the like can be restricted by the side wall of the housing 20, or the movement of the diaphragm 50 can be restricted by making the corner shape of the housing 20 oblique. Further, the horizontal movement of the vibrating membrane 50 can be restricted by a member such as a pin. In addition, it is desirable that the edge (peripheral end) of the vibrating membrane 50 is housed in the housing 20 in a state where it can freely vibrate. The vibration film 50 can be vibrated in a free end state, and vibrations according to the electrical signals supplied to the wirings 61a to 61f can be excited in the vibration film 50.

  FIG. 5 shows a schematic configuration of a terminal unit 70 for connecting the wirings 61a to 61f on the front and back of the vibrating membrane 50 to the outside, for example, a personal computer (PC) serving as a host device. The vibration membrane 50 includes six wirings 61a to 61f in total on the front and back sides, and twelve connection terminals 62 in total on the front and back surfaces are provided on the connection piece 58 integrated with the vibration membrane 50, and the six wirings 61a. ˜61f are connected to both ends. The terminal unit 70 arbitrarily includes a first wiring group 76 including 12 wirings connected to the 12 connection terminals 62, and a first wiring group 76 and a second wiring group 77 including 12 wirings. The first switching unit 71 connected to the second switching unit 72, the second switching unit 72 that switches the combination of the twelve wirings included in the second wiring group 77, and the third wiring group 78. A general-purpose interface connected, for example, a USB interface 73 is included. Further, the terminal unit 70 includes a first controller 74 that controls the first switching unit 71 and a second controller 75 that controls the second switching unit 72.

  The first switching unit 71 includes a wiring of the first wiring group 76 on the output side electrically connected to the wirings 61a to 61f of the vibration film 50 and a second wiring on the input side by a selector or a crossbar switch. The wiring of the wiring group 77 is connected, and the control of the first controller 74 switches the connection between the first wiring group 76 and the second wiring group 77 randomly or cyclically in units of clocks. When switching to random or cyclic, the first controller 74 always switches both ends of the wirings 61a to 61f of the vibrating membrane 50 so as to form a pair. Therefore, when the second wiring group 77 on the input side is used, it is only necessary to select a wiring corresponding to any of the wirings 61a to 61f without considering switching to random or cyclic.

  The timing for switching may be an appropriate period (cycle), may be in units of one clock, may be in units of several clocks, or may be in units of several tens of clocks. When digital audio signals in units of clocks are supplied to the wirings 61a to 61f of the vibrating membrane 50, the signals supplied to the wirings 61a to 61f are controlled by controlling the first switching unit 71 so as to switch in units of clocks. It can be switched at the same cycle as the digital audio signal.

  The six wirings 61a to 61f formed on the front and back surfaces of the vibration membrane 50 are basically designed and formed (manufactured) so as to have the same wiring length and the same combination of lengths in the vertical and horizontal directions. The However, when manufacturing tolerances and film thickness tolerances at the time of manufacturing a printed wiring board overlap, the resistance values and areas of the respective wirings 61a to 61f may fluctuate slightly. As a result, even if the same current is supplied to each of the wirings 61a to 61f, the amplitude and frequency of the vibrating membrane 50 may fluctuate slightly, and a subtle unnatural feeling may occur in the output sound. By randomly selecting the wirings 61a to 61f by the first switching unit 71 and exchanging (switching) the wirings 61a to 61f, the output of the diaphragm 50 can be averaged and the sound quality can be improved. Further, as described above, since the electric signals supplied to the respective wirings 61a to 61f can be averaged within a certain time range, the force for moving the vibrating membrane 50 in the horizontal direction can be canceled and vibrated in a stable state. be able to. The first switching unit 71 may select (switch) the wirings 61a to 61f cyclically in a short time unit.

  The second switching unit 72 also includes an appropriate connection circuit element capable of switching connections such as a selector and a crossbar switch, and the combination of connections of the six wires 61 a to 61 f can be changed via the connection terminal 62. For example, the wirings 61a to 61f can be connected in series, partially connected in series, or connected in combination of series and parallel. For example, if the resistance of each of the wirings 61a to 61f is 4Ω, when a voltage of 4V is applied to both ends, the wirings 61a to 61f of the speaker 10 can be used as six speakers having a resistance of 4Ω and an output of 4W.

  As shown by a broken line in FIG. 5, a combination of two wirings, for example, wirings 61a and 61d and wirings 61b and 61e are connected in series, and further connected in parallel to It can be used as one speaker with an overall resistance of 4Ω and an output of 4W. Formally, four of the six wires are used, but the six wires 61a to 61f are used by switching to random or cyclic by the first switching unit 71.

  Further, by connecting two of the wirings 61a to 61f in series, the speaker 10 can be used as three speakers having a resistance of 8Ω and an output of 2W. Further, by connecting four of the wires 61a to 61f in series, the speaker 10 can be used as one speaker with a resistance of 16Ω and an output of 1W. For this reason, the speaker 10 can be set to a speaker having a resistance and an output that match the specifications of the host-side device by simply changing the setting of the second switching unit 72. For this reason, the speaker 10 can be easily used for various applications such as the output of a smartphone and the output of an audio device, and can be easily used for a plurality of applications.

  FIG. 6 shows a different type of printed wiring board 80 provided with the vibrating membrane 50. This printed wiring board 80 can be housed in the housing 20 instead of the printed wiring board (resin film) 59 shown in FIG. 2, and the speaker 10 can be configured in the same manner as in the above example.

  The printed wiring board 80 includes a vibration film 50 and a substrate portion 81 integrated with the vibration film 50. A processing unit 85 is mounted (mounted) on the substrate portion 81, and is connected to the wirings 61 a to 61 f on the front and back of the vibrating membrane 50 by connection wirings 82. In addition, a plurality of slits 83 are provided between the vibration film 50 and the substrate portion 81 along a boundary 89 between the vibration film 50 and the substrate portion 81, and the vibration film 50 using the substrate portion 81 as a vibration body. To be separated from Thereby, the wiring pattern 60 and the processing unit 85 of the vibrating membrane 50 are mounted on a common printed wiring board (circuit board) without deteriorating the performance (vibration) of the vibrating membrane 50. 60 and the processing unit 85 can be electrically connected. The configuration of the vibrating membrane 50 is the same as described above, and a description thereof will be omitted.

  The processing unit 85 may be provided as a chip (LSI, ASIC), or a processing circuit may be formed directly on the printed wiring board 80. The processing unit 85 includes a digital amplifier function 86 and supplies a digital acoustic signal to each of the wirings 61 a to 61 f of the vibrating membrane 50 via the connection wiring 82.

  FIG. 7 shows digitalization of the CD system as an example of the principle of digital recording. The horizontal axis represents time (t), and the vertical axis represents the voltage (v) of the electrical signal corresponding to the voice. In this case, the digitization is performed by dividing the original audio signal shown by the curve 98 into a sampling period (for example, 22.7 μsec) on the time axis, and the voltage value therebetween is represented by digital data, for example, as shown by a broken line 99. It is recorded in the form of 16-bit binary number (quantization). Conventionally, when digital data is reproduced as an acoustic signal, the digital signal is returned to an analog voltage by an analog converter (D / A converter) to drive a speaker. At this time, the voltage directly output from the D / A converter is a quantized stepped voltage (jagged) indicated by a broken line 99 in the figure. The sound is hard to hear.

  The Super Audio CD (SACD) system performs high frequency sampling (spreading Linz period 0.35 μsec) at the recording stage, and ΔΣ modulation (1 bit, 2.8224 MHz) data is directly applied to the Super Audio CD board during A / D conversion. Record. This is a method of expressing the size of an audio signal by the density (shading) of a 1-bit digital pulse, and has an order of magnitude performance compared to a conventional CD having a dynamic range of 120 db and a frequency characteristic of 100 KHz or more.

  The digital amplifier function 86 of the processing unit 85 drives the speaker with a digital logic circuit. That is, after receiving a digital signal, sound is reproduced by supplying the digital signal independently to the wirings (circuits) 61a to 61f of the diaphragm (diaphragm) 50 directly without performing analog conversion. For example, when the digital amplifier function 86 receives a 24-bit digital signal, the digital amplifier function 86 is decomposed into six wirings (circuits) 61a to 61f, and is controlled so as to output information for four bits through one wiring within a certain time. To do. The resolution per time per wiring is not limited to 4 bits, but may be 4 bits or more.

  The digital amplifier function (digital amplifier unit) 86 has a processing capability of about 100 MHz and divides a quantized sampling period, for example, 2.8 MHz into 16 in the time direction. Accordingly, as schematically shown in FIG. 8, the digital amplifier function 86 converts the input 24-bit digital signal 91 into 6 circuits × 16 bits (16 divisions in the time direction), specifically, a reproduction signal 92, specifically 6 One signal 92.1 to 92.6 is converted and supplied directly to each of the wirings 61a to 61f. In the vibration film 50 of the speaker 10, the wiring 61 a to 61 f vibrates up and down by digital signals (reproduction signals) 92 supplied independently from each other, and a sound obtained by synthesizing vibrations from the reproduction signal 92 is generated from the vibration film 50. Is output.

  Since the reproduction signal 92 is divided into 16 bits in the time direction, as shown in FIGS. 9A to 9P, values of 0 to 15 can be distributed and output in the time direction. 9 (a) shows the value 0, FIG. 9 (b) shows the value 1, FIG. 9 (c) shows the value 2, FIG. 9 (d) shows the value 3, and FIG. FIG. 9 (f) shows the value 5, FIG. 9 (g) shows the value 6, FIG. 9 (h) shows the value 7, FIG. 9 (i) shows the value 8, and FIG. 9 (j) indicates the value 9, FIG. 9 (k) indicates the value 10, FIG. 9 (l) indicates the value 11, FIG. 9 (m) indicates the value 12, and FIG. 9 (n) indicates the value. 13, FIG. 9 (o) shows the value 14, and FIG. 9 (p) shows the value 15.

  Therefore, the digital amplifier function 86 selects an appropriate 4 bits from these outputs, and the reproduction signal 92 is transmitted to each wiring (circuit) of the diaphragm 50 so that a total 24 bits signal is reproduced as the diaphragm 50. It supplies to 61a-61f.

  As described above, each of the wirings 61a to 61f is equivalent in terms of circuit, but there may be a slight difference in mechanical performance, and load distribution among the wirings 61a to 61f can be achieved. desirable. For this reason, the processing unit 85 includes a function (supply unit) 87 that supplies the wirings 61a to 61f with the reproduction signal 92 being switched at random or cyclically so as to achieve load distribution.

  As described above, the speaker 10 including the printed wiring board 80 can be driven only by the logic circuit if there is a premise that there is a digital signal. Therefore, a digital / analog conversion circuit, an analog amplifier circuit, and a power supply circuit necessary for the amplifier are unnecessary, and a compact, power-saving and high-output speaker can be provided. Further, since the processing unit 85 for driving the speaker is a digital drive, that is, an on / off only switch, there is no heat generation on the circuit side, and no heat sink or the like is required. Furthermore, since the speaker can be driven with a voltage close to the power supply voltage, there is also an advantage that it can be used with lower power than the analog type.

  In the above description, the speaker 10 including the vibration film 50 in which three wirings (three circuits) are formed on each of the front and back sides is described as an example. However, the number of wirings provided on the vibration film 50 is limited to this. Alternatively, two wirings, four or more wirings, or the vibrating membrane 50 in which wiring is provided only on one of the surfaces may be used. For example, when the wiring pattern 60 is two wirings, the two wirings are arranged at symmetrical positions around the magnetization boundary 36. In the above description, the wiring pattern 60 is folded back in the longitudinal direction (vertical direction) of the vibration film 50, but may be folded back in the width direction (lateral direction) of the vibration film 50. The number of wiring patterns 60 that are meandering or zigzag bent (turned) is not limited to three. If the vibration film 50 is small, the wiring pattern 60 may be straight. The wiring pattern 60 preferably includes an even number of first array patterns 65, and in this case, the turn portion (second wiring pattern 66) of the wiring pattern 60 is preferably odd.

  Further, the positions of the through holes (vent holes) 34 provided in the magnet plates 31 and 32 are arbitrary, but it is desirable to arrange them along the magnetization boundary 36 where the displacement of the vibration film 50 increases. Further, the arrangement of the through holes 34 may be a staggered pattern or a lattice pattern, and may be circular, oval, or polygonal.

  In the above description, a speaker that outputs sound is described as an example of an electroacoustic conversion device. However, a microphone that converts sound into an electric signal may be used. In this case, characteristics may be set flexibly or a digital signal may be used. Can be provided.

10 Speaker, 31, 32 Magnet plate, 50 Vibration membrane

Claims (10)

A magnet plate including a multipolar magnetized magnetized surface;
Having a vibration film arranged so as to oppose the magnetized surface and the buffer material;
The vibrating membrane includes a wiring pattern including a plurality of independent wirings to which different electrical signals are applied,
The electroacoustic transducer according to claim 1, wherein the wiring pattern is an array pattern extending along a magnetization boundary of the multipolar magnetized magnetized surface, and includes a symmetrical array pattern centered on the magnetization boundary.   2. The electroacoustic transducer according to claim 1, wherein an arrangement order of the plurality of wirings included in the array pattern along the adjacent magnetization boundary is reversed.   3. The electroacoustic transducer according to claim 1, wherein the vibration film includes the wiring pattern on both surfaces.   4. The electroacoustic transducer according to claim 1, wherein the magnetized surface is multipolarly magnetized in a stripe shape. In any one of Claims 1 thru | or 4, It has a connection piece integrated with the said diaphragm further,
The connection piece includes an electroacoustic transducer including a plurality of connection ends that electrically connect each of the plurality of wirings to an external wiring.   6. The electroacoustic transducer according to claim 5, further comprising a connection unit that switches an electric signal input or output to each of the plurality of wirings via the plurality of connection ends in units of clocks. In any one of Claims 1 thru | or 4, Furthermore, the board | substrate integrated with the said vibration film,
An electroacoustic transducer comprising: a processing unit mounted on the substrate, wherein the processing unit supplies a digital acoustic signal to each of the plurality of wirings.   8. The electroacoustic transducer according to claim 7, further comprising a slit provided along a boundary between the vibration film and the substrate on which the processing unit is mounted.   9. The electroacoustic transducer according to claim 7, wherein the processing unit includes a connection function for switching a digital acoustic signal supplied to each of the plurality of wirings in units of clocks. The electroacoustic transducer according to any one of claims 1 to 9,
A speaker having a housing that houses the electroacoustic transducer.

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