JP6541964B2 - Condenser speaker and method of driving the same - Google Patents

Description

  The present invention relates to a condenser speaker and a method of driving the same.

  A capacitor speaker is an electrostatic type speaker which generates an acoustic wave (air vibration) by vibrating the electrode by the coulomb force of the charge generated between the electrodes by applying a high voltage and an acoustic signal in parallel between the parallel plate electrodes. It is known as a kind of

  The circuit configuration of a conventional condenser speaker is shown in FIG. The movable electrode 52 is held at its both ends by the cushioning insulating damper 54, and these are held by the first and second fixed electrodes 51, 53, and DC by the DC power supply 55 via the step-up transformer 56. A bias voltage is applied. That is, positive charges are charged to the first and second fixed electrodes 51 and 53, and negative charges are charged to the movable electrode 52. M10 to which one end of the DC power supply 55 is connected represents the position of the secondary side center tap of the step-up transformer 56.

  Here, when the acoustic signal source 57 is applied to the primary side of the step-up transformer 56, the acoustic signal is applied to the first and second fixed electrodes 51 and 53 which are secondary sides of the step-up transformer 56.

FIG. 12 shows the relationship between the voltages of the movable electrode 52 and the first and second fixed electrodes 51 and 53, V _A10 , V _X10 , and V _Y10 with the potential of M10 as a reference potential. A voltage of opposite phase is applied to the first and second fixed electrodes 51 and 53, and an appropriate oscillating electric field is applied to the movable electrode 52. That is, due to the change of the electric field strength due to the acoustic signal applied to the primary side of the step-up transformer 56, the movable electrode 52 having a negative charge generates a mechanical vibration according to the electric field strength by the coulomb force. The electrode 52 vibrates to generate a sound wave.

  Here, the voltage applied to the DC power supply 55 is usually several hundred volts to 1 kV, and a Cockcroft-Waltron type booster circuit in which capacitors and diodes are connected in multiple stages or a piezoelectric element (PLZT element) using a ferroelectric is used. The booster circuit used is proposed (patent documents 1-2).

As another configuration of the capacitor speaker, there is also known a configuration in which a high voltage power source is not required by using a pre-charged electret material as a movable electrode or a fixed electrode (Patent Document 3).
Unexamined-Japanese-Patent No. 9-182190 JP, 2011-30047, A JP, 2008-312109, A

  In the case of the conventional capacitor speaker, since a DC high voltage and an acoustic signal which is an AC signal are superimposed and applied to the step-up transformer, a large step-up transformer having a high insulation property is required. Therefore, not only the overall size of the device is increased, but also it is necessary to provide a current limiting function to ensure safety, which complicates the circuit configuration. Furthermore, a typical Cockcroft-Waltron circuit as a booster circuit requires an expensive high breakdown voltage capacitor component, which is not preferable in terms of operating temperature and operating life. Furthermore, there is also a problem that high frequency noise is easily generated.

  Conventional high voltage generation circuits that do not use a step-up transformer contribute to miniaturization, but their temperature characteristics tend to be unstable, and their volume decreases when the DC bias voltage is small, which causes problems when applied to condenser speakers. there were.

  The present invention has been made in view of the circumstances as described above. A step-up transformer is not necessary and the circuit configuration is simple. Furthermore, even if it is a high voltage, only a current of the level of everyday static electricity flows. Technical challenge is to provide a condenser speaker that can be

The condenser speaker according to the present invention is
A movable electrode; and a first fixed electrode disposed opposite to the movable electrode;
A first photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the first fixed electrode,
A first bleeder resistor consisting of two dividing resistors connected in series is connected in parallel to the first photodiode row,
A first LED control unit to which a detection voltage divided by the dividing resistor from the voltage generated from the first photodiode array and an acoustic signal voltage obtained by adding a DC bias voltage are input, An output from the LED control unit is connected to a first light emitting diode, and the first photodiode array is disposed in the vicinity of a light irradiation surface of the first light emitting diode. .

  With such a configuration, it is possible to inexpensively provide a condenser speaker that realizes a compact, lightweight, and highly temperature stable operation while preventing an electric shock to the human body.

Further, in the capacitor speaker according to the present invention, the first fixed electrode, the second fixed electrode disposed to face the first fixed electrode, and the first and second fixed electrodes are provided. And movable electrodes facing the first and second fixed electrodes,
A first photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the first fixed electrode,
A second photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the second fixed electrode,
A first bleeder resistor comprising two dividing resistors connected in series is connected in parallel to the first photodiode row, and the second photodiode row is the same as the first bleeder resistor. A second bleeder resistor having a resistance value is connected in parallel, and a detection voltage divided by the dividing resistor from the voltage generated from the first photodiode row and an acoustic signal voltage obtained by adding a DC bias voltage are input A second LED control unit, the first output from the second LED control unit is connected to a first light emitting diode, and the first output and the acoustic signal component are in reverse phase; An output of 2 is connected to a second light emitting diode, the first photodiode row is disposed in the vicinity of a light irradiation surface of the first light emitting diode, and the second photodiode row is Characterized in that it is arranged in the vicinity of the light irradiation surface of the serial second light emitting diodes.

  With such a configuration, it is possible to provide a push-pull type capacitor speaker in which the movable electrode vibrates by the first fixed electrode and the second fixed electrode, and it is possible to improve the speaker characteristics in the low frequency range.

  Further, according to another embodiment of the above-described capacitor speaker according to the present invention, the first or second LED control unit is configured by a combination of an operational amplifier and an LED driver, or a combination of an operational amplifier and a power MOSFET. There is.

  As a result, the light emission intensity (light intensity) of the light emitting diode (LED) can be controlled in accordance with the acoustic signal, and by using the power MOSFET, a lower priced capacitor speaker can be provided.

  In the condenser speaker according to the present invention, a condenser capacity formed between the first movable electrode and the first fixed electrode, and a first bleeder connected in parallel to the first photodiode row It is characterized in that the reciprocal of the time constant determined by the product of the resistance and the resistance value is equal to or higher than the drive frequency of the condenser speaker.

  With such a configuration, it is possible to output a sound up to a desired frequency range from the condenser speaker, and it is possible to have a function as a low pass filter when PWM modulating an acoustic signal.

  The capacitor speaker according to the present invention is characterized in that at least the first LED control unit, the first light emitting diode, and the first photodiode row are mounted in the same package.

  Such a configuration makes it possible to realize further reduction in size and weight and to obtain more stable temperature characteristics.

  In the condenser speaker according to the present invention, at least the second LED control unit, the first light emitting diode, the first photodiode row, the second light emitting diode, and the second photodiode row are included. It is characterized in that it is implemented in the same package.

  With such a configuration, even in the push-pull type condenser speaker, it is possible to realize further reduction in size and weight, and further stable temperature characteristics can be obtained.

  The capacitor speaker according to the present invention is characterized in that the first light emitting diode and the first photodiode row are formed on a nitride semiconductor grown on the front and back surfaces of a sapphire substrate.

  With such a configuration, light emission and light reception can be performed at the same wavelength, the efficiency of photoelectric conversion can be increased, and more stable characteristics can be obtained.

In addition, the condenser speaker according to the present invention is
The first light emitting diode and the first photodiode array are formed on a nitride semiconductor grown on the front and back surfaces of a sapphire substrate, and the second light emitting diode and the second photodiode array are formed. Are formed on a nitride semiconductor grown on the front and back surfaces of the sapphire substrate.

  With such a configuration, even in the push-pull type condenser speaker, the efficiency of photoelectric conversion can be increased, and more stable characteristics can be obtained.

In addition, a capacitor speaker according to the present invention comprises a transparent movable electrode having electrical conductivity, a first fixed electrode, and a second fixed electrode.
The first fixed electrode and the second fixed electrode are connected to the secondary side terminal of the step-up transformer,
One end of a photodiode array comprising a plurality of photodiodes connected in series is connected to the transparent movable electrode,
The other end of the photodiode array is connected to a center tap on the secondary side of the step-up transformer,
A light emitting diode is disposed to illuminate the photodiode array,
A DC power supply is connected to both terminals of the light emitting diode,
An acoustic signal source is connected to the step-up transformer,
The light from the light emitting diode is irradiated to at least a part of the transparent movable electrode.

  With such a configuration, it is possible to obtain irradiation of light from the condenser speaker together with the sound wave, which makes it possible to check the operating condition, and to obtain a condenser speaker having an electric decoration effect.

In the capacitor speaker according to the present invention, the movable electrode is a transparent movable electrode plate having electrical conductivity,
The light of the first light emitting diode or the second light emitting diode is irradiated to at least a part of the transparent movable electrode plate.

  With such a configuration, the intensity of light emitted from the condenser speaker changes with the acoustic signal, and it is possible to produce a further illumination effect.

  Further, the condenser speaker according to the present invention is characterized in that a removable filter is provided between the first fixed electrode and the movable electrode.

  Such a configuration makes it possible to realize a condenser speaker having an air cleaning function.

Further, a method of driving a condenser speaker according to the present invention is
Causing the first light emitting diode to emit light according to the first output outputted from the first LED control unit according to the acoustic signal;
By applying a voltage generated from the first photodiode row to the first fixed electrode of a capacitor speaker according to the light emission intensity of the first light emitting diode, the first fixed electrode and the movable electrode Driving the movable electrode in response to a change in the electric field between
The detection voltage divided by the dividing resistor connected in parallel to the first photodiode array is negatively fed back to the first LED control unit from the voltage generated from the first photodiode array, and the acoustic A voltage obtained by adding a DC bias voltage to a signal is input to the first LED control unit,
The first LED control unit may generate the first output according to a voltage difference between the detection voltage and a voltage obtained by adding a direct current bias to the acoustic signal.

  With such a configuration, a high voltage modulation signal is obtained by irradiating a plurality of photodiode rows connected in series with light from the LED modulated by an acoustic signal, and the high voltage modulation signal is applied between parallel plate electrodes. The moving electrode is mechanically vibrated by the coulomb force of the charge generated to generate a sound wave, and the divided high voltage modulation signal is negatively fed back to control the drive current of the LED to the human body. The stabilization of temperature characteristics can be realized while eliminating the risk of electric shock.

Further, a method of driving a condenser speaker according to the present invention is
Causing the first light emitting diode to emit light by a first output output from the second LED control unit according to the acoustic signal;
Causing the second light emitting diode to emit light by a second output in which an acoustic signal component is in reverse phase to the first output output from the second LED control unit;
Applying a first voltage generated from the first photodiode row according to the light emission intensity of the first light emitting diode to the first fixed electrode of the capacitor speaker;
Applying a second voltage generated from the second photodiode array to the second fixed electrode of the capacitor speaker in accordance with the light emission intensity of the second light emitting diode;
Driving the movable electrode according to a change in electric field between the first fixed electrode and the second fixed electrode;
From the voltage generated from the first photodiode array, the detected voltage divided by the dividing resistor connected in parallel to the first photodiode array is negatively fed back to the second LED control unit.
A voltage obtained by adding a DC bias to the acoustic signal is input to the second LED control unit,
The first output and the second output are generated from the second LED control unit in accordance with a voltage difference between the detection voltage and a voltage obtained by adding a direct current bias to the acoustic signal. .

  With such a configuration, it is possible to realize stabilization of temperature characteristics while eliminating the risk of electric shock to the human body even for a push-pull type condenser speaker.

  The present invention has a configuration that does not use a capacitor in place of the conventional Cockcroft-Waltron circuit, and further provides a stable sound quality by providing a circuit that eliminates the influence of environmental changes due to operating temperature etc. A small (especially thin) and long-life condenser speaker can be provided.

Configuration diagram of the condenser speaker in the first embodiment Voltage characteristic chart at each point of the condenser speaker in the first embodiment Configuration diagram of a condenser speaker in the second embodiment Configuration diagram of the condenser speaker in the third embodiment Voltage characteristic chart at each point of the condenser speaker in the third embodiment Cross-sectional view of a package mounted with a component for electrical signal processing of a condenser according to a fourth embodiment Cross-sectional view of a package mounted with a component for electrical signal processing of a condenser according to a fifth embodiment Configuration diagram of the condenser speaker in the sixth embodiment Voltage characteristic chart at each point of the condenser speaker in the sixth embodiment Circuit configuration of a condenser speaker with an air purifying function in the seventh embodiment Diagram of conventional condenser speaker Voltage characteristic chart at each point of conventional condenser speaker

First Embodiment
FIG. 1 shows a circuit configuration of a condenser speaker system according to a first embodiment of the present invention. The AC (AC) acoustic signal output from the acoustic signal source 1 is applied with a DC bias voltage generated from the variable bias power supply 3 via the coupling capacitor 2 and is input to the positive side input terminal of the operational amplifier 4. The resistive element 5 connected in series to the variable bias power supply 3 prevents the acoustic signal output from the acoustic signal source 1 from flowing to the ground side via the variable bias power supply 3.

  The output of the operational amplifier 4 is connected to the LED (light emitting diode) 7 via the LED driver 6, and the drive current of the LED 7 changes according to the output voltage of the operational amplifier 4, and the light emission intensity of the LED 7 changes. That is, the operational amplifier 4 and the LED driver 6 constitute an LED control unit that modulates the light emission intensity of the LED 7 according to the voltage of the acoustic signal which is the input signal.

  A photodiode row 8 in which a plurality of photodiodes are connected in series is disposed in the vicinity of the light irradiation surface of the LED 7. If, for example, 1000 photodiodes each having a photovoltaic power of about 0.6 V are connected in series, and a sufficient amount of light is generated to generate photovoltaic power from the LED 7 to all the photodiodes of the photodiode array 8, A voltage of about 600 V is generated at both ends of the photodiode row.

  One end of the photodiode array 8 is connected to the ground, and the other end is connected to the movable electrode 11. Further, the photodiode array 8 is provided with a bleeder resistor 9 composed of two dividing resistors 9a and 9b in order to reduce the time constant. Thus, when the light irradiation is stopped, the high voltage generated at both ends of the photodiode row 8 is discharged quickly, and the decrease in the operating frequency of the entire circuit is suppressed.

  Note that the dividing resistors may substantially divide the resistors. For example, it may be composed of two or more resistive elements, or conversely, may be composed of an integral resistive element having a dividing point.

  As shown in FIG. 1, a bleeder resistor 9 consisting of two split resistors 9 a and 9 b is connected in parallel to both ends of the photodiode array 8, and the split point S 1 of the two split resistors 9 a and 9 b corresponds to that of the operational amplifier 4. Connected to negative input terminal (negative feedback connection).

The voltage at both ends of the photodiode array 8 is simply divided by the resistance ratio of the dividing resistors 9a and 9b. For example, division point S1 is provided at a point where voltage division ratio = 1000: 1 (= division resistance ratio 9a: 9b), and the potential at this division point S1 is V _S1 . V _S1 includes a DC voltage of about 0.6 V, and the DC bias voltage of the variable bias power supply 3 corresponds to this DC voltage.

FIG. 2 shows temporal changes in voltages V _A1 , V _S1 and V _M1 at points A1, S1 and M1 based on the potential at point M1 in the circuit shown in FIG.

  According to the above circuit configuration, the output voltage of the photodiode row 8 is modulated to follow the acoustic signal from the acoustic signal source 1, and the capacitor speaker can be driven by this output voltage.

  The mechanical portion of the condenser speaker includes a fixed electrode 10 provided with an opening and a movable electrode (vibrating electrode) 11. The fixed electrode 10 is made of, for example, stainless steel. The movable electrode 11 is formed of, for example, a laminated structure such as a polyester film to which an aluminum foil is bonded, and both ends thereof are held by an insulating damper 12 made of, for example, urethane rubber. That is, the fixed electrode 10 and the movable electrode 11 are provided to face each other at a predetermined distance apart from each other, and are electrically insulated.

That is, a parallel plate capacitor is formed by the fixed electrode 10 and the movable electrode 11. Then, assuming that the photovoltaic power from the photodiode array 8 is Vp and the capacity of the capacitor is Cx, the charges induced on the electrodes are Cx · Vp, and the electric field strength between the electrodes is d between the electrodes. For example, Vp / d. As a result, the coulomb force that the two electrodes receive is the product Cx · Vp ² / d of them. Since this coulomb force temporally changes according to the acoustic signal, the movable electrode 11 mechanically vibrates to generate a sound wave, and the sound wave is output through the aperture of the fixed electrode 10.

  As described above, the bleeder resistors (dividing resistors 9a and 9b) play a role in detecting the voltage generated from the photodiode array 8 and at the same time with a role in reducing the time constant. Assuming that the resistance value of the bleeder resistance is Rx (= Ra + Rb), this capacitor speaker has a time constant determined by the product Rx · Cx. Ra and Rb are resistance values of the dividing resistors 9a and 9b, respectively.

  Considering that the upper limit of the frequency in the human audible sound range is about 20 kHz, it is necessary to drive the condenser speaker at this frequency. Therefore, the acoustic signal frequency can be reproduced by the condenser speaker by satisfying the condition of 1 / (Rx · Cx)> 20 KHz.

  The sound wave output from the condenser speaker is not necessarily limited to the audible sound. If necessary, the ultrasonic wave can be generated from the condenser speaker by setting the time constant to a high frequency equal to or higher than the audio frequency and setting the time constant to a smaller value.

  Further, when the acoustic signal is PWM-modulated, if the sampling frequency is, for example, about 10 times that of the acoustic signal, that is, 200 kHz, there is a risk that noise generated due to the high frequency may be mixed in the condenser speaker. However, since the configuration of the condenser speaker based on the above time constant functions as a low pass filter, there is an effect of blocking such noise.

  Next, the stable driving principle of the capacitor speaker using the negative feedback of the operational amplifier 4 will be described.

  The operational amplifier 4 shown in FIG. 1 operates as a differential amplifier. Therefore, an electric signal (for example, a voltage obtained by multiplying the voltage difference by a constant amplification factor) corresponding to the voltage difference between the detection voltage S1 input to the negative input terminal of the operational amplifier 4 and the input voltage of the positive input terminal is output. Be done.

Even in this case, the light intensity of the LED 7 or the output voltage of the photodiode array 8 is decreased due to, for example, an increase in environmental temperature, and the input voltage to the positive input terminal and the input voltage to the negative input terminal of the operational amplifier 4 When the voltage difference between the operational amplifier 4 and the amplifier 7 increases, the output voltage of the operational amplifier 4 increases, the drive current of the LED 7 increases via the LED driver 6, and the light intensity of the LED 7 increases. As a result, the output voltage of the photodiode row 8 and the detection voltage V _S1 rise, and the voltage difference changes in the direction of reduction. If the luminous intensity of the LED 7 or the output voltage of the photodiode array 8 rises due to a decrease in environmental temperature or the like, the operational amplifier 4 operates in the opposite manner to the above.

  That is, since the detection voltage S1 is negatively fed back, the operational amplifier 4 operates in the direction of canceling out the change of the detection voltage S1 due to the environmental temperature or the like, and the stable operation becomes possible.

Second Embodiment
In the first embodiment, an integrated circuit can be used as the LED driver 6, but a power MOSFET may be used instead.

  In FIG. 3, the output of the operational amplifier 4 is connected to the gate terminal of the n-channel power MOSFET 13 as an LED driver. The power MOSFET 13 supplies the current of the LED 7 such as a blue light emitting diode by the power supply 14 with a DC voltage of 6V. The resistance element 39 is a resistance element for LED protection.

  Thus, cost can be reduced by using a power MOSFET instead of the LED driver.

Third Embodiment
FIG. 4 is a structure of a condenser speaker system according to a third embodiment of the present invention. The AC (AC) acoustic signal output from the acoustic signal source 1 is applied with a DC bias voltage generated from the variable bias power supply 3 through the coupling capacitor 2 and is input to the positive side input terminal of the operational amplifier 15 having a complementary output terminal. It is input. As in the first embodiment, a resistive element 5 is connected in series to the variable bias power supply 3.

  The complementary output of the operational amplifier 15 is connected to the first LED driver 16R and the second LED driver 16L.

  As in the first embodiment, the first and second LED drivers 16R and 16L control the LED drive current according to the output of the operational amplifier 15, and the first LED 17R and the second LED 17L Drive each.

  It should be noted here that the electric signals output from the first and second LED drivers 16R and 16L have the same DC bias voltage component and the acoustic signal components in opposite phase. Therefore, the photovoltaic power generated in the first photodiode row 18R and the second photodiode row 18L has the same direct current component by being irradiated with light from the first LED 17R and the second LED 17L. The acoustic signals of opposite phase are superimposed and applied to each of them.

  Similar to the first embodiment, the first and second photodiode rows 18R and 18L are disposed in the vicinity of the irradiation surfaces of the light from the first and second LEDs 17R and 17L, respectively. For example, 1000 photodiodes each having a photovoltaic power of about 0.6 V, for example, are connected in series, and photovoltaics are applied to all the photodiodes of the first and second LEDs 17R, 17L to the first and second photodiode rows 18R, 18L. If light with a sufficient amount of light is generated to generate power, a voltage of about 600 V is generated at both ends of the first and second photodiode rows 18R and 18L.

  First and second bleeder resistors 19R and 19L are connected in parallel to the first and second photodiode rows 18R and 18L, respectively, and these first and second bleeder resistors 19R and 19L are They are set to the same resistance value.

The first bleeder resistor 19R is configured by series connection of two divided resistors 19Ra and 19Rb. The detection voltage V _S2 at the dividing point S2 by the dividing resistors 19Ra and 19Rb is input to the negative input terminal of the operational amplifier 15.

  The first LED driver 16R, the first LED 17R, and the first bleeder resistor 19R collectively constitute a negative feedback circuit of the operational amplifier 15 to ensure stable operation of the entire system.

  The mechanical portion of the capacitor speaker includes a first fixed electrode 20R provided with an opening, a second fixed electrode 20L provided with an opening, and a movable electrode 21. The first and second fixed electrodes 20R and 20L are made of, for example, stainless steel. Both ends of the movable electrode 21 are held by the insulating damper 22. The materials and structures of the movable electrode 21 and the insulating damper 22 may be the same as those of the first embodiment.

  That is, a pair of parallel plate capacitors is formed by the first fixed electrode 20R and the second fixed electrode 20L. Then, a signal voltage in which an acoustic signal is added to a DC high voltage is applied between the electrodes of each capacitor. Here, since the operational amplifier 15 outputs in a complementary manner, vibration voltages whose acoustic signal components are in opposite phase are applied to the first fixed electrode 20R and the second fixed electrode 20L.

  As a result, when the attractive force from one of the movable electrodes 21 becomes strong, the other can be functioned as a “push-pull type condenser speaker” in which the attractive force becomes weak.

FIG. 5 shows a graph in which the horizontal axis is represented as a time axis for each voltage V _X4 and V _Y4 of the first fixed electrode 20R and the second fixed electrode 20L, with the movable electrode 21 as a reference point A4.

  It can be seen that the voltage relationship between the fixed electrode and the movable electrode is similar to the voltage relationship of the capacitor speaker using the conventional transformer shown in FIG. That is, when viewed from the movable electrode 21, the coulomb force changes in accordance with the acoustic signal in the first fixed electrode 20R and the second fixed electrode 20L which are the left and right fixed electrodes. The movable electrode 21 is vibrated by the coulomb force to generate a sound wave, and the sound wave is output through the opening of the first fixed electrode 20R and the second fixed electrode 20L.

  As described above, by the configuration of the movable electrode 21, the first fixed electrode 20R, and the second fixed electrode 20L, a push-pull type capacitor speaker can be provided, and in particular, the speaker characteristics can be improved in the low frequency range It becomes.

  In the present invention, it is preferable to ground the fixed electrode side for safety. For example, if the side generating the acoustic signal is the second fixed electrode 20L, it is safe for the human body to touch by grounding Y4. Further, it is possible to ground both of the two fixed electrodes, the first fixed electrode 20R and the second fixed electrode 20L, and the safety in that case is further enhanced.

  Also in this embodiment, a power MOSFET may be used instead of the LED driver.

  Also in the present embodiment, the relationship between the reciprocal of the time constant determined by the product of the capacitor capacitance between the movable electrode and the fixed electrode and the bleeder resistance and the operation (drive) frequency of the speaker is the same as in the first embodiment. It is.

  Further, in the present embodiment, when the direction (polarity) of the photodiode in the high voltage generating portion is opposite to that in the first and second embodiments, that is, the potential of the movable electrode becomes lower than the potential of both fixed electrodes. Although the embodiment has been shown, the direction of the photodiode may be reversed and the potential of the movable electrode may be set higher than the potentials of both fixed electrodes as in the first and second embodiments. In the second embodiment, the direction of the photodiode may be reversed. Also in other embodiments, although not particularly mentioned, it is possible to reverse the orientation of the photodiode.

Fourth Embodiment
FIG. 6A is an example of a cross-sectional view in which the component processing the electrical signal of the first embodiment is mounted in one package.

  6A shows that the control unit 23 corresponding to the operational amplifier 4 and the LED driver 6 in the electronic circuit shown in FIG. 1, the light emitting element unit 24 corresponding to the LED 7, and the light receiving element unit 25 corresponding to the photodiode row 8 It is shown mounted on the frames 26a, 26b.

  The coupling capacitor 2 and the resistance element 5 in the electronic circuit shown in FIG. 1 may be incorporated in the control unit 23 or may be connected to an external terminal formed of a lead frame. Similarly, the bleeder resistance may be built in the control unit 23 or the light receiving element unit 25 or may be connected to the outside via the lead frames 26a and 26b.

  The control unit 23, the light emitting element unit 24, and the light receiving element unit 25 are all connected to the lead frames 26a to 26c by bonding wires 27 made of, for example, gold or copper. Alternatively, the light receiving element unit 25 may be formed of, for example, a silicon photodiode, and the control unit 23 may be formed on the same chip by being formed of an integrated circuit on a silicon substrate.

  The light emitting element portion 24 and the light receiving element portion 25 are provided to face each other via the light transmitting resin 28, and the light receiving element portion 25 is disposed in the vicinity of the irradiation surface of light from the light emitting element portion 24.

  Furthermore, the whole is covered with a light shielding resin 29 for mold sealing, and the control unit 23, the light emitting element unit 24 and the light receiving element unit 25 are configured as an integrated package.

  In FIG. 6 (a), the lead frames 26a and 26b are respectively provided only on one side of the package, but not limited to one side, and may have external terminals on both sides, if necessary. It goes without saying that the shape and configuration of the lead frame can be freely designed.

  With the above configuration, the drive current output from the control unit 23 causes the LED of the light emitting element unit 24 to emit light, and the light emitted from the light emitting element unit 24 passes through the translucent resin 28 and the light receiving element unit 25. Generate photovoltaic power. That is, the voltage generated in the photodiode row 8 that is the light receiving element unit 25 is output as an output voltage, for example, by the bonding wire 27 via the lead frame functioning as a connection terminal to the outside. A capacitor speaker (not shown) is driven by the output voltage of the photovoltaic power to generate an acoustic wave.

  By thus mounting the control unit 23, the light emitting element unit 24 and the light receiving element unit 25 in an integrated package, further reduction in size and weight can be realized. In addition, since the temperature difference between the two becomes extremely small and all the elements operate at substantially the same temperature, the reliability for stable driving of the light emitting element unit 24 by the temperature compensation of the control unit 23 is further improved.

  Although this embodiment has described the case where the circuit configuration of the first embodiment is packaged, the power driver may be used instead of the LED driver as described in the second embodiment, or the other equivalent. Naturally, it may be replaced by one having a function as an LED drive circuit.

  Further, FIG. 6A shows an example in which the control unit 23 and the light receiving element unit 25 are integrated on a single silicon substrate on a single chip, but as shown in FIG. 6B, the light receiving element unit 25 and the control unit 23 may be separately prepared and connected by a bonding wire 27. Furthermore, in this case, as shown in FIG. 6C, the vertical relationship between the light emitting element unit 24 and the light receiving element unit 25 may be reversed.

  It is also possible to form the light emitting element unit 24 and the control unit 23 in the same chip. In this case, the integrated circuit of the control unit 23 may be an integrated circuit made of silicon, a compound semiconductor as the light emitting element unit 24, and both mixed together using SOI (Silicon On Insulator) technology or SOS (Silicon On Sappire) technology. It is possible.

  Furthermore, the light emitting element portion 24 and the light receiving element portion 25 can be integrated on the same substrate by using crystal growth of nitride semiconductor (for example, GaN) on the front and back surfaces of the sapphire substrate 42. In FIG. 6D, the LED as the light emitting element portion 24 and the photodiode row as the light receiving element portion 25 are formed on the nitride semiconductor grown on the front and back surfaces of the sapphire substrate 42 and integrated with the control portion 23 An example implemented in the package of The light from the light emitting element unit 24 is irradiated to the light receiving element unit 25 through the sapphire substrate 42, so the translucent resin 28 is not necessary.

  In this case, light emission and light reception can be performed at the same wavelength by the LED as the light emitting element unit 24 and the photodiode row as the light receiving element unit 25, and the efficiency of photoelectric conversion can be enhanced. Furthermore, in LED light emission of a nitride semiconductor, there is a tendency to shift to a short wavelength side as the number of injection carriers increases, so there is also an advantage that the light absorptivity of the nitride semiconductor photodiode array increases. The LEDs of the light emitting element unit 24 may be a plurality of rows (arrays), which is the same as in the other embodiments.

  6D shows an example in which the stacked structure of the light emitting element 24, the sapphire substrate 42, and the light receiving element 25 and the control unit 23 are mounted on an integrated package, but only the stacked structure is integrated. It may be implemented in a package of

  In addition, as a form of a package, various forms, such as DIP, SOP, QFP, QFN, and BGA, are employable. All these points are the same as in the other embodiments.

Fifth Embodiment
FIG. 7 is an example of a cross-sectional view in which the component processing the electrical signal of the third embodiment is mounted in one package. In the third embodiment, two sets of the combination of the light emitting element and the light receiving element are used. FIG. 7 shows that even in such a case, mounting in the same package is possible.

  7A shows a control unit 23 corresponding to the operational amplifier 15 and the first and second LED drivers 16R and 16L in the electronic circuit shown in FIG. 4, and a light emitting element unit corresponding to the first and second LEDs 17R and 17L. Light receiving element sections 25R and 25L corresponding to 24R and 24L and first and second photodiode rows 18R and 18L are shown mounted on lead frames 26c, 26e and 26d.

  The control unit 23, the light emitting element units 24R and 24L, and the light receiving element units 25R and 25L are all connected to the lead frames 26c to 26e by bonding wires 27 made of, for example, gold or copper.

  The light emitting element portion 24R and the light receiving element portion 25R are provided to face each other via the light transmitting resin 28R, and the light receiving element portion 25R is disposed in the vicinity of the irradiation surface of light from the light emitting element portion 24R. Similarly, the light emitting element portion 24L and the light receiving element portion 25L are provided to face each other via the translucent resin 28L, and the light receiving element portion 25L is disposed in the vicinity of the irradiation surface of light from the light emitting element portion 24L. Be done.

  Furthermore, the whole is covered with a light shielding resin 29 for mold sealing, and the control unit 23, the light emitting element units 24 (24R, 24L), and the light receiving element units 25 (25R, 25L) are configured as an integrated package.

  Further, in FIG. 7A, the light receiving element sections 25R and 25L are formed by, for example, photodiodes made of silicon, and the control section 23 is also formed by an integrated circuit on a silicon substrate, thereby being integrated on a single chip. Although an example is shown, as shown in FIG. 7 (b), the light receiving element sections 25R and 25L and the control section 23 may be separately prepared and connected by the bonding wire 27, and further shown in FIG. 7 (c). As a matter of course, the vertical relationship between the light receiving element portions 25R and 25L and the light emitting element portions 24L and 24R may be reversed. In the figure, reference numerals 26c to 26g denote lead frames.

  In FIG. 7, the lead frames 26c to 26g are provided only on one side of the package, but the lead frames are not limited to one side, and may have external terminals on both sides. It goes without saying that the shape and configuration can be designed freely.

  Further, similarly to the example shown in FIG. 6 (d), also in this embodiment, a laminated structure in which the light emitting element portion and the light receiving element portion are formed on the front and back surfaces of the sapphire substrate may be used.

  In the present embodiment, the case where the circuit configuration of the third embodiment is packaged has been described, but even if a power MOSFET is used instead of the LED driver, it has a function as another equivalent LED drive circuit. Naturally, it may be replaced by.

  The coupling capacitor 2 and the resistance element 5 in the electronic circuit shown in FIG. 4 may be incorporated in the control unit 23 or may be connected (externally attached) to an external terminal formed of a lead frame. It may be built in the light receiving element unit 25L, 25R or the control unit 23, or may be externally connected (externally connected) via a lead frame. This is the same in the fourth embodiment.

Sixth Embodiment
FIG. 8 is a circuit configuration diagram of a condenser speaker system according to a fourth embodiment. The mechanism portion of the condenser of the system includes first and second fixed electrodes 34R and 34L provided with openings and a transparent movable electrode (vibrating electrode) 32. Each of the first and second fixed electrodes 34R and 34L is made of, for example, stainless steel. The transparent movable electrode 32 is formed of, for example, a laminated structure in which a conductive thin film 31 is formed on a thin transparent acrylic resin 30, and both ends thereof are held by an insulation damper 33 made of, for example, urethane rubber. That is, each of the first and second fixed electrodes 34R and 34L and the transparent movable electrode 32 are provided to face each other with a predetermined distance therebetween, and are electrically insulated.

  The thickness of the transparent acrylic resin 30 is, for example, 0.5 mm, and the conductive thin film 31 is, for example, a metal thin film such as gold formed by vacuum evaporation, and the thickness is 50 nm.

  As in the first and third embodiments, the photodiode row 37 is disposed in the vicinity of the plane irradiated with the light from the LED 36. If, for example, 1000 photodiodes each having a photovoltaic power of about 0.6 V are connected in series and all the photodiodes of the photodiode row 37 are irradiated with light of a light amount sufficient to generate the photovoltaic power from the LED 36, A voltage of about 600 V is generated at both ends of the photodiode row 37.

  One end of the photodiode array 37 is connected to the transparent movable electrode 32, and the other end is connected to the center tap on the secondary side of the step-up transformer 38. In addition, 39 is a resistive element for LED protection.

  Both terminals of the secondary side of the step-up transformer 38 are connected to the first and second fixed electrodes 34R and 34L.

  A negative charge is charged on the transparent movable electrode 32 between the transparent movable electrode 32 and the first and second fixed electrodes 34L and 34R by a voltage generated by the photodiode row 37.

  Here, when the acoustic signal source 40 is applied to the primary side of the step-up transformer 38, the acoustic signal is superimposed on the first and second fixed electrodes 34L and 34R connected to the secondary side of the step-up transformer 38. Applied. The change in electric field strength between the first and second fixed electrodes 34R and 34L according to the acoustic signal mechanically vibrates the transparent movable electrode 32 to generate a sound wave, and the sound wave is generated by the first and second sound waves. It is output through the openings of the fixed electrodes 34R, 34L.

  By guiding and irradiating a part of the irradiation light from the LED 36 to the end of the transparent acrylic resin 30 during this series of operations, it is possible to cause the condenser speaker that is the acoustic conversion unit to emit light.

  By providing fine irregularities on the surface of the transparent acrylic resin 30, irregular reflection occurs on the surface of the light, and the light can be viewed from the outside through the openings of the first and second fixed electrodes 34R and 34L. it can. In this case, since the LED 36 is made to emit light by the power supply 35, a stable light intensity can be obtained.

  With the above-described configuration, when the condenser speaker emits light, the operating state can be clearly understood, and an electric decoration effect can be obtained.

FIG. 9 shows the potential V _A8 of the transparent movable electrode 32, the potential V _{Y8 of} the first fixed electrode 34R, and the potential V _{X8 of} the second fixed electrode 34L based on the secondary side center tap point M8 of the step-up transformer 38. Shows the relationship between In this embodiment, this voltage relationship is similar to that of a conventional condenser speaker.

  Although the case where light reflected from the transparent movable electrode of the capacitor speaker has a constant luminous intensity has been described here, also in the first to third embodiments, as in this embodiment, transparent acrylic as the movable electrode If the light from the LED is guided to the transparent movable electrode using the transparent movable electrode made of a laminated structure of resin and conductive thin film, the light modulated by the acoustic signal component is extracted to the outside, and the decoration effect is further achieved. It is also possible to produce

  The transparent acrylic resin is merely an example of the transparent plate, and it goes without saying that other transparent resins such as polyethylene and thin glass may be used.

Seventh Embodiment
FIG. 10 is a circuit diagram of a condenser speaker with an air purifying function in a seventh embodiment. In the present embodiment, a filter 41 for air cleaning is disposed between the movable electrode 22 and the first and second fixed electrodes 20R and 20L in the capacitor speaker shown in FIG. The filter 41 preferably has a large surface area and is removable. As such, for example, a HEPA filter etc. correspond.

  As described above, a high voltage is applied between the first and second fixed electrodes 20R and 20L and the fixed electrode 22 during the capacitor speaker operation. Therefore, foreign matter in the air that has passed through the openings of the first and second fixed electrodes 20 L and 20 R is charged and drawn to the movable electrode 22.

  Therefore, by installing the removable filter 41 having a large surface area between the electrodes, the condenser speaker can function as an electric dust collecting type air cleaner. If filter 41 is made removable, regular replacement is easy.

  In particular, the condenser speaker according to the present invention is compact and lightweight and is safe for the human body, so that it is possible to provide a speaker with an air cleaning function that can be easily attached to the wall of a general household.

  In the present embodiment, an example of the air cleaner using the condenser speaker shown in FIG. 4 is shown, but in the condenser speaker shown in FIG. 1 or FIG. The same is true even if a possible filter 41 is installed.

Reference Signs List 1 acoustic signal source 2 coupling capacitor 3 variable bias power supply 4 operational amplifier 5 resistance element 6 LED driver 7 LED
8 photodiode array 9a, 9b split resistor 10 fixed electrode 11 movable electrode 12 insulation damper 13 power MOSFET
14 power supply 15 operational amplifier 16R having complementary output terminals first LED driver 16L second LED driver 17R first LED
17L second LED
18R 1st photodiode array 18L 2nd photodiode array 19R 1st bleeder resistance 19L 2nd bleeder resistance 19Ra, 19Rb Divided resistance 20R 1st fixed electrode 20L 2nd fixed electrode 21 movable electrode 22 insulating damper 23 Control part 24, 24R, 24L Light emitting element part 25, 25L, 25R Light receiving element part 26a, 26b, 26c, 26d, 26e, 26f Lead frame 27 Bonding wire 28 Translucent resin 29 Light shielding resin 30 Transparent acrylic resin 31 Conductive thin film 32 Transparent movable electrode 33 Insulating damper 34L, 34R First and second fixed electrodes 35 Power supply 36 LED
37 photodiode array 38 step-up transformer 39 resistance element 40 acoustic signal source 41 filter 42 sapphire substrate 51, 53 first and second fixed electrodes
52 movable electrode 54 insulation damper 55 DC power supply 56 step-up transformer 57 electric potential V _{A1 of} movable electrode 11 potential V _{A10 of} movable electrode 52 potential V _{A4 of} movable electrode plate 21 _M1 potential V _M1 ground point of ground V _M10 boost transformer 56 Potential of the secondary side center tap position of
V _S1 , V _S2 detection potential at the division point V _X10 potential of the fixed electrode 51
V _{X 4} Potential of first fixed electrode 20 L V _{Y 10} Each potential of fixed electrode 53
V _{Y 4} second fixed electrode 20 R potential V _{M 8} step-up transformer 38 secondary-side center tap potential V A ₈ transparent movable electrode 32 potential V _{Y 8} first fixed electrode 34 R potential V _{X 8} second fixed electrode 34 L Potential of

Claims (14)

A movable electrode; and a first fixed electrode disposed opposite to the movable electrode;
A first photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the first fixed electrode,
A first bleeder resistor consisting of two dividing resistors connected in series is connected in parallel to the first photodiode row,
A first LED control unit to which a detection voltage divided by the dividing resistor from the voltage generated from the first photodiode array and an acoustic signal voltage obtained by adding a DC bias voltage are input;
An output from the first LED controller is connected to a first light emitting diode,
The condenser speaker according to claim 1, wherein the first photodiode row is disposed in the vicinity of a light irradiation surface of the first light emitting diode. A first fixed electrode, a second fixed electrode disposed to face the first fixed electrode, and the first and second fixed electrodes; A movable electrode facing the fixed electrode of the
A first photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the first fixed electrode,
A second photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the second fixed electrode,
A first bleeder resistor consisting of two dividing resistors connected in series is connected in parallel to the first photodiode row,
A second bleeder resistor having the same resistance value as the first bleeder resistor is connected in parallel to the second photodiode row,
A second LED control unit to which a detection voltage divided by the dividing resistor from the voltage generated from the first photodiode array and an acoustic signal voltage obtained by adding a DC bias voltage are input;
A first output from the second LED controller is connected to a first light emitting diode,
A second output in which the first output and the acoustic signal component are in anti-phase are connected to a second light emitting diode;
The first photodiode array is disposed in the vicinity of a light irradiation surface of the first light emitting diode.
The condenser speaker characterized in that the second photodiode row is disposed in the vicinity of a light irradiation surface of the second light emitting diode.   The condenser speaker according to claim 1, wherein the first LED control unit includes an operational amplifier and an LED driver or a power MOSFET.   The condenser speaker according to claim 2, wherein the second LED control unit includes an operational amplifier and an LED driver or a power MOSFET.   Determined by the product of the capacitance of the capacitor formed between the first movable electrode and the first fixed electrode and the resistance value of the first bleeder resistor connected in parallel to the first photodiode row The condenser speaker according to any one of claims 1 to 4, characterized in that the reciprocal of the time constant to be set is equal to or higher than the driving frequency of the condenser speaker.   6. The device according to claim 1, wherein at least the first LED control unit, the first light emitting diode, and the first photodiode row are mounted in the same package. Condenser speaker as described. That at least the second LED control unit, the first light emitting diode, the first photodiode row, the second light emitting diode and the second photodiode row are mounted in the same package The condenser speaker according to claim 2 or 4 characterized by the above-mentioned.   7. The nitride semiconductor according to claim 1, wherein the first light emitting diode and the first photodiode array are formed on a nitride semiconductor grown on the front surface and the back surface of a sapphire substrate. Condenser speaker according to 1 or 1. The first light emitting diode and the first photodiode array are formed on a nitride semiconductor grown on the front and back surfaces of a sapphire substrate, and the second light emitting diode and the second photodiode array are formed. The capacitor speaker according to any one of claims 2, 4 and 7, characterized in that is formed on a nitride semiconductor grown on the front surface and the back surface of the sapphire substrate. A transparent movable electrode having electrical conductivity, a first fixed electrode, and a second fixed electrode;
The first fixed electrode and the second fixed electrode are connected to the secondary side terminal of the step-up transformer,
One end of a photodiode array comprising a plurality of photodiodes connected in series is connected to the transparent movable electrode,
The other end of the photodiode is connected to a center tap on the secondary side of the step-up transformer,
A light emitting diode is disposed to illuminate the photodiode array,
A DC power supply is connected to both terminals of the light emitting diode,
An acoustic signal source is connected to the step-up transformer,
The condenser speaker characterized in that light from the light emitting diode is irradiated to at least a part of the transparent movable electrode. The movable electrode is a transparent electrode plate having electrical conductivity,
The condenser speaker according to any one of claims 1 to 5, wherein light of the first light emitting diode is irradiated to at least a part of the transparent electrode plate.   The condenser speaker according to any one of claims 1 to 11, further comprising: a removable filter between the first fixed electrode and the movable electrode. A movable electrode; and a first fixed electrode disposed opposite to the movable electrode;
A first photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the first fixed electrode,
A first bleeder resistor consisting of two dividing resistors connected in series is connected in parallel to the first photodiode row,
A first LED control unit to which a detection voltage divided by the dividing resistor from the voltage generated from the first photodiode array and an acoustic signal voltage obtained by adding a DC bias voltage are input;
The first light output from the first LED control unit causes the first light emitting diode to emit light.
By applying a voltage generated from the first photodiode row to the first fixed electrode of a capacitor speaker according to the light emission intensity of the first light emitting diode, the first fixed electrode and the movable electrode Driving the movable electrode in response to a change in the electric field between
The detection voltage divided by the dividing resistor connected in parallel to the first photodiode array is negatively fed back to the first LED control unit from the voltage generated from the first photodiode array, and the acoustic A voltage obtained by adding a DC bias voltage to a signal is input to the first LED control unit,
A method of driving a condenser speaker comprising: controlling the first output according to a voltage difference between the detection voltage and a voltage obtained by adding a direct current bias to the acoustic signal, and generating the first output from the first LED control unit. . A first fixed electrode, a second fixed electrode disposed to face the first fixed electrode, and the first and second fixed electrodes; A movable electrode facing the fixed electrode of the
A first photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the first fixed electrode,
A second photodiode row consisting of a plurality of photodiodes connected in series is connected to the movable electrode and the second fixed electrode,
A first bleeder resistor consisting of two dividing resistors connected in series is connected in parallel to the first photodiode row,
A second bleeder resistor having the same resistance value as the first bleeder resistor is connected in parallel to the second photodiode row,
A second LED control unit to which a detection voltage divided by the dividing resistor from the voltage generated from the first photodiode array and an acoustic signal voltage obtained by adding a DC bias voltage are input;
A first output output from the second LED control unit is connected to a first light emitting diode,
A second output in which the first output and the acoustic signal component are in antiphase from the second LED control unit is connected to a second light emitting diode; and the first output causes the first light emitting diode to Make it glow,
The second output causes the second light emitting diode to emit light,
Applying a first voltage generated from the first photodiode row according to the light emission intensity of the first light emitting diode to the first fixed electrode of the capacitor speaker;
Applying a second voltage generated from the second photodiode array to the second fixed electrode of the capacitor speaker in accordance with the light emission intensity of the second light emitting diode;
Driving the movable electrode according to a change in electric field between the first fixed electrode and the second fixed electrode;
From the voltage generated from the first photodiode array, the detected voltage divided by the dividing resistor connected in parallel to the first photodiode array is negatively fed back to the second LED control unit.
A voltage obtained by adding a DC bias to the acoustic signal is input to the second LED control unit,
The first output and the second output are generated from the second LED control unit in accordance with a voltage difference between the detection voltage and a voltage obtained by adding a direct current bias to the acoustic signal. How to drive a condenser speaker.

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