WO2003043748A1 - Heat-induced pressure wave generator - Google Patents

Heat-induced pressure wave generator Download PDF

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Publication number
WO2003043748A1
WO2003043748A1 PCT/JP2002/012100 JP0212100W WO03043748A1 WO 2003043748 A1 WO2003043748 A1 WO 2003043748A1 JP 0212100 W JP0212100 W JP 0212100W WO 03043748 A1 WO03043748 A1 WO 03043748A1
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Prior art keywords
heat
heating element
pressure wave
wave generator
induced pressure
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PCT/JP2002/012100
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French (fr)
Japanese (ja)
Inventor
Hiroyuki Shinoda
Nobuyoshi Koshida
Naoya Asamura
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Japan Science And Technology Agency
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Publication of WO2003043748A1 publication Critical patent/WO2003043748A1/en

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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K15/00—Acoustics not otherwise provided for
    • G10K15/04—Sound-producing devices

Definitions

  • the present invention relates to a heat-induced pressure wave generator that generates a pressure wave by heating a medium such as air, and more particularly to a speaker and an ultrasonic generator.
  • Measurement fields such as distance measurement and liquid level measurement, detection of humans and objects in monitoring systems, automobiles and robots
  • the present invention has been made in view of the above circumstances, and has as its object to provide a heat-induced pressure wave generator capable of dramatically increasing the generation efficiency and power of heat-induced ultrasonic waves.
  • the present invention in order to achieve the above object,
  • a heat-induced pressure wave generator comprising an electrically driven heating element electrode, wherein the area of the heating element electrode is reduced and the power applied to the heating element electrode is concentrated in a short time. It is characterized by increasing the time-average power of the generated sound with respect to the time-average input power by forming a periodic or aperiodic pulse shape or a burst wave shape.
  • a heat-induced pressure wave generator including a substrate, a heat insulating layer provided on the substrate, and an electrically driven heating element electrode provided on the heat insulating layer.
  • an acoustic horn is connected to the heating element electrode to increase the power of the transmitted sound.
  • the heating element electrode is formed in a fold shape, the area where the heating element electrode is in contact with air is increased, and a strong pressure wave is generated. Is generated.
  • the groove or hole is a cylindrical or prismatic groove or hole, and a plurality of heating element electrodes are arranged on the inner wall of the groove or hole.
  • the plurality of heating element electrodes advance in the longitudinal direction of the cylindrical or prismatic groove or hole. It is characterized by generating strong pressure waves.
  • the substrate and the heating element electrode are supported by supporting the heating element electrode with a large number of minute projections. It is characterized in that thermal insulation is performed between the two.
  • FIG. 1 is a configuration diagram of a thermally induced pressure wave generator showing an embodiment of the present invention.
  • FIG. 2 is an explanatory diagram of a method for temporally driving a heating element electrode according to an embodiment of the present invention.
  • FIG. 3 is an equivalent circuit diagram for calculating the generated sound pressure of the thermally induced ultrasonic wave of the present invention.
  • FIG. 4 is a schematic view of a modification of the heating element electrode according to the embodiment of the present invention.
  • FIG. 5 is a perspective view of the third heating element electrode shown in FIG. 4 (c).
  • FIG. 6 is a configuration diagram of a flat heating element electrode divided into horizontal square holes, showing an embodiment of the present invention.
  • FIG. 7 is a sectional view showing a heat insulating structure according to another embodiment of the present invention.
  • FIG. 1 is a configuration diagram of a thermally-induced pressure wave generator showing an embodiment of the present invention.
  • FIG. 1 (a) is a sectional view thereof, and
  • FIG. 1 (b) is a plan view thereof.
  • 1 is a substrate
  • 2 is a heat insulating layer
  • 3 is a heating element electrode
  • 4 is a wiring to a heating element electrode
  • 5 is an acoustic horn
  • 6 is a signal for applying a current to the heating element electrode 3.
  • the sound pressure P ( ⁇ ) of the generated sound wave is proportional to the input power q ( ⁇ ), and if the acoustic impedance at the radiation surface is equal, the power input to the unit area and the sound pressure of the generated sound wave ⁇ The ratio of ( ⁇ ) is equal regardless of frequency. ”
  • the acoustic volume for the same input power increases.
  • the current flowing through the circuit at that time corresponds to the particle velocity of air near the heating element electrode surface, and the voltage across Z corresponds to the generated sound pressure.
  • ⁇ ⁇ ⁇ ⁇ (C / ⁇ ) 1 ⁇ 8 5 (at 1 0 0 kHz)
  • K is the thermal conductivity of air, and a is the specific heat ratio (about 1.4 for air). For example, if the frequency is 100 kHz,
  • the current value and the temperature that can be tolerated by the heating element electrode will eventually be exceeded.
  • the following structure of the heating element electrode may be used.
  • FIG. 4 is a schematic view of a modified example of the heating element electrode showing the embodiment of the present invention.
  • FIG. 4 (a) shows an example of a sawtooth-shaped heating element electrode
  • FIG. 4 (c) shows an example of a shaped heating element electrode
  • FIG. 4 (c) shows an example of a divided heating element electrode arranged in the groove.
  • a heat insulating layer 8 is formed on a sawtooth-shaped substrate 7, and a sawtooth heating element electrode 9 is formed on the heat insulating layer 8. I do.
  • the sawtooth heating element electrode 9 is connected to a signal source 1 °. 1 1 represents the radiated sound wave.
  • the generated sound pressure becomes X times.
  • the condition at this time is when the height of the sawtooth is sufficiently smaller than the generated sound wavelength.
  • the saw-tooth-shaped heating element electrode 9 has been described. However, various shapes can be used as long as folds are formed.
  • a heat insulating layer 13 is formed on the inner wall of the groove of the grooved substrate 12, and the groove is formed on the heat insulating layer 13.
  • the shape heating element electrode 14 is formed.
  • a signal source 15 is connected to the groove-shaped heating element electrode 14. 16 represents the emitted sound waves.
  • the generated sound pressure can be increased as compared with a flat heating element electrode.
  • a heat insulating layer 18 is formed on the inner wall of the groove of the hole-shaped substrate 17 and the heat insulating layer 18 is formed.
  • the groove-shaped heating element electrodes 19a, 19b, and 19c divided on 18 are formed.
  • the generated sound pressure can be increased as compared with a flat heating element electrode.
  • the space can be configured to be surrounded by the electrodes.
  • the heating element electrodes are divided into sub-wavelength sizes like the divided hole-shaped heating element electrodes 19 a, 19 b, and 19 c, and each is divided into signal sources 20 a, 20 O
  • this structure is extended to obtain a strong sound pressure proportional to the area of the heating element electrode. You can do that too.
  • FIG. 6 is a configuration diagram of a divided plate-shaped heating element electrode showing another example.
  • a heat insulating layer (not shown) is formed in the square hole of the substrate 31 with a horizontal square hole, and the plate-like heating element electrodes 32a, 32b, which are divided only on the lower surface of the square hole.
  • a signal source (not shown) is connected to these divided flat-plate-shaped electrodes 32 a, 32 b, and 32 c.
  • 33 represents the emitted sound wave.
  • FIG. 7 is a sectional view showing a heat insulating structure according to another embodiment of the present invention.
  • protrusions 42 instead of using a solid film-like heat insulating layer, as shown in FIG. 7, protrusions 42 with a spacing w of about 10 m are formed on a substrate 41, and the protrusions are formed. 4 2 supports the heating element electrode 4 3.
  • the thickness of the heating element electrode 43 about 10 nm or less and making the insulation between the heating element electrode 43 and the substrate 41 extremely good, the noise generated per unit power consumption can be improved.
  • the pressure power can be increased.
  • the present invention is not limited to the above embodiments, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.
  • the heat induction of the heat induction ultrasonic generator The efficiency of generating ultrasonic waves and the maximum generated sound pressure can be dramatically improved, which not only exceeds the performance of conventional sound equipment and ultrasonic generators, but also enables new applications of powerful ultrasonic waves. Become. For example, it is possible to realize a device that can use not only the measurement application but also the non-linear effects of audio equipment and strong ultrasonic waves.
  • the heat-induced pressure wave generator of the present invention can dramatically improve the heat-induced ultrasonic wave generation efficiency and the maximum generated sound pressure, and can be used not only for acoustic equipment and ultrasonic generators, but also for parametric arrays and the like. It can be used as an ultrasonic generator such as a non-linear acoustic element, a radiation pressure actuator, and a tactile display.

Abstract

A heat-induced pressure wave generator having a greatly enhanced efficiency of generation of a heat-induced ultrasonic wave and generating a greatly increased power. The heat-induced pressure wave generator comprises a substrate (1), a heat-insulating layer (2) provided on the substrate (1), and a heater electrode (3) provided on the heat-insulating layer (2) and electrically driven. The heater electrode (3) has a small area. The current applied to the heater electrode (3) is shaped into a periodic, aperiodic, or burst wave where the power is concentrated in a short time. Therefore, the temporal average power of the generated sound with respect to the temporal average input power is increased.

Description

技術分野 Technical field
本発明は、 空気などの媒体を加熱して圧力波を発生させる熱誘起圧力波発生装 置に係り、 スピーカーや超音波発生装置に関するものである。 距離計測や液面計 測などの計測分野、 監視システムにおける人間や物体の検出、 自動車やロボット 明  The present invention relates to a heat-induced pressure wave generator that generates a pressure wave by heating a medium such as air, and more particularly to a speaker and an ultrasonic generator. Measurement fields such as distance measurement and liquid level measurement, detection of humans and objects in monitoring systems, automobiles and robots
などが障害物や周囲の物体を検出するためのセンサ、 自動車の乗員の位置や姿勢 細 Sensors to detect obstacles and surrounding objects, and the position and
のセンサ、 音響機器 （スピーカー）、非線形音響素子、 パラメトリックアレイ装 置、 マイクロアセンブリや微小物体操作 （放射圧によって非接触で物体を操作す る） 、触覚ディスプレイをはじめとしたバーチャルリアリティなどの技術分野に 属する。 背景技術 Technical fields such as sensors, audio equipment (loudspeakers), non-linear acoustic elements, parametric array devices, micro-assembly and small object operation (operate objects in a non-contact manner by radiation pressure), virtual reality such as tactile displays Belongs to Background art
従来、 このような分野の技術として、圧電材料や固体膜を振動させ、 空中に超 音波を発生させるようにしたものがある。  Conventionally, as a technique in such a field, there is a technique in which a piezoelectric material or a solid film is vibrated to generate ultrasonic waves in the air.
一方、 上記の技術とは異なった先行技術として、 特開平 1 1一 3 0 0 2 7 4号 によって、 熱誘起超音波発生装置が提案された。 これにより、 従来にない広い帯 域の超音波を発生させることが可能になり、 集積化超音波ァレイの実現も容易と なった。 発明の開示  On the other hand, as a prior art different from the above-mentioned technology, a heat-induced ultrasonic generator has been proposed by Japanese Patent Application Laid-Open No. Hei 11-310274. This makes it possible to generate ultrasonic waves in a wider band than ever before, making it easy to realize an integrated ultrasonic array. Disclosure of the invention
しかしながら、 上記した従来の熱誘起超音波発生装置は、超音波の発生効率が 悪く、 発生可能な音波のパヮ一も小さいために、実用されるには至っていない。 本発明は、 上記状況に鑑みて、熱誘起超音波の発生効率と発生パワーを飛躍的 に増大させることができる熱誘起圧力波発生装置を提供することを目的とする。 本発明は、 上記目的を達成するために、  However, the above-mentioned conventional heat-induced ultrasonic generator has not been put to practical use because the generation efficiency of ultrasonic waves is low and the size of sound waves that can be generated is small. The present invention has been made in view of the above circumstances, and has as its object to provide a heat-induced pressure wave generator capable of dramatically increasing the generation efficiency and power of heat-induced ultrasonic waves. The present invention, in order to achieve the above object,
〔 1〕 基板と、 この基板上に設けられる熱絶縁層と、 この熱絶縁層上に設けら れ、電気的に駆動される発熱体電極とを具備する熱誘起圧力波発生装置において、 前記発熱体電極の面積を小さくするとともに、前記発熱体電極に印加する電流を、 短い時間にパワーが集中している周期的あるいは非周期的パルス状あるいはバ一 スト波状にすることによって、 時間平均投入電力に対する発生音の時間平均パヮ —を高めることを特徴とする。 [1] A substrate, a heat insulating layer provided on the substrate, and a heat insulating layer provided on the heat insulating layer. A heat-induced pressure wave generator comprising an electrically driven heating element electrode, wherein the area of the heating element electrode is reduced and the power applied to the heating element electrode is concentrated in a short time. It is characterized by increasing the time-average power of the generated sound with respect to the time-average input power by forming a periodic or aperiodic pulse shape or a burst wave shape.
〔2〕 基板と、 該基板上に設けられる熱絶縁層と、 該熱絶縁層上に設けられ、 電気的に駆動される発熱体電極とを具備する熱誘起圧力波発生装置において、 前 記発熱体電極の面積を小さくするとともに、 前記発熱体電極に音響ホーンを接続 し、 送出される音のパワーを増大させることを特徴とする。  [2] A heat-induced pressure wave generator including a substrate, a heat insulating layer provided on the substrate, and an electrically driven heating element electrode provided on the heat insulating layer. In addition to reducing the area of the body electrode, an acoustic horn is connected to the heating element electrode to increase the power of the transmitted sound.
〔 3〕 上記 〔 2〕 記載の熱誘起圧力波発生装置において、前記音響ホーンは、 熱誘起超音波の実効放射ィンピ一ダンスと整合した音響ホーンであることを特徴 とする。  [3] The heat-induced pressure wave generator according to [2], wherein the acoustic horn is an acoustic horn that matches an effective radiation impedance of thermally-induced ultrasonic waves.
〔 4〕 上記 〔 1〕 又は 〔 2〕 記載の熱誘起圧力波発生装置において、前記発熱 体電極の形状をヒダ状となし、前記発熱体電極が空気に接する面積を大きくし、 強力な圧力波を発生させることを特徴とする。  [4] In the heat-induced pressure wave generator according to the above [1] or [2], the heating element electrode is formed in a fold shape, the area where the heating element electrode is in contact with air is increased, and a strong pressure wave is generated. Is generated.
〔 5〕 上記 〔 1〕 又は 〔 2〕記載の熱誘起圧力波発生装置において、前記発熱 体電極を前記基板に形成される溝又は孔の内壁に形成し、前記発熱体電極が空気 に接する面積を大きくし、 強力な圧力波を発生させることを特徴とする。  [5] The heat-induced pressure wave generator according to [1] or [2], wherein the heating element electrode is formed on an inner wall of a groove or a hole formed in the substrate, and an area where the heating element electrode is in contact with air. And a strong pressure wave is generated.
〔 6〕 上記 〔 5〕 記載の熱誘起圧力波発生装置において、 前記発熱体電極を分 割し、 この分割された電極を所定の方向に進行する進行波と同期したタイミング で駆動することによつて強力な圧力波を発生させることを特徴とする。  [6] The heat-induced pressure wave generator according to [5], wherein the heating element electrodes are divided, and the divided electrodes are driven at timing synchronized with a traveling wave traveling in a predetermined direction. A strong pressure wave is generated.
〔 7〕 上記 〔 5〕 記載の熱誘起圧力波発生装置において、 前記溝又は孔は円柱 形状又は角柱形状の溝又は孔であり、 この溝又は孔の内壁に複数の発熱体電極を 配置し、 前記円柱形状又は角柱形状の溝又は孔の長手方向に進行する波動に同期 したタイミングで前記複数の発熱体電極を駆動することによって、前記円柱形状 又は角柱形状の溝又は孔の長手方向に進行する強力な圧力波を発生させることを 特徴とする。  (7) In the heat-induced pressure wave generator according to (5), the groove or hole is a cylindrical or prismatic groove or hole, and a plurality of heating element electrodes are arranged on the inner wall of the groove or hole. By driving the plurality of heating element electrodes at a timing synchronized with the wave propagating in the longitudinal direction of the cylindrical or prismatic groove or hole, the plurality of heating element electrodes advance in the longitudinal direction of the cylindrical or prismatic groove or hole. It is characterized by generating strong pressure waves.
〔 8〕 上記 〔 1〕 又は 〔 2〕 記載の熱誘起圧力波発生装置において、 前記発熱 体電極を微小な多数の突起物により支えることによって、前記基板と発熱体電極 の間の熱絶縁を行うことを特徴とする。 図面の簡単な説明 [8] In the heat-induced pressure wave generator according to [1] or [2], the substrate and the heating element electrode are supported by supporting the heating element electrode with a large number of minute projections. It is characterized in that thermal insulation is performed between the two. BRIEF DESCRIPTION OF THE FIGURES
第 1図は、 本発明の実施例を示す熱誘起圧力波発生装置の構成図である。  FIG. 1 is a configuration diagram of a thermally induced pressure wave generator showing an embodiment of the present invention.
第 2図は、 本発明の実施例を示す発熱体電極の時間的な駆動方法の説明図であ る。  FIG. 2 is an explanatory diagram of a method for temporally driving a heating element electrode according to an embodiment of the present invention.
第 3図は、 本発明の熱誘起超音波の発生音圧を計算するための等価回路図であ る。  FIG. 3 is an equivalent circuit diagram for calculating the generated sound pressure of the thermally induced ultrasonic wave of the present invention.
第 4図は、 本発明の実施例を示す発熱体電極の変形例の模式図である。  FIG. 4 is a schematic view of a modification of the heating element electrode according to the embodiment of the present invention.
第 5図は、 第 4図 （c ) に示される第 3の発熱体電極の斜視図である。 ' 第 6図は、 本発明の実施例を示す横向き角孔への分割された平板状発熱体電極' の構成図である。  FIG. 5 is a perspective view of the third heating element electrode shown in FIG. 4 (c). FIG. 6 is a configuration diagram of a flat heating element electrode divided into horizontal square holes, showing an embodiment of the present invention.
第 7図は、 本発明の他の実施例を示す熱絶縁構造を示す断面図である。 発明を実施するための最良の形態  FIG. 7 is a sectional view showing a heat insulating structure according to another embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION
以下、本発明の実施の形態について詳細に説明する。  Hereinafter, embodiments of the present invention will be described in detail.
第 1図は本発明の実施例を示す熱誘起圧力波発生装置の構成図であり、 第 1図 ( a ) はその断面図、 第 1図 （b ) はその平面図である。  FIG. 1 is a configuration diagram of a thermally-induced pressure wave generator showing an embodiment of the present invention. FIG. 1 (a) is a sectional view thereof, and FIG. 1 (b) is a plan view thereof.
これらの図において、 1は基板、 2は熱絶縁層、 3は発熱体電極、 4は発熱体 電極 3への配線、 5は音響ホーン、 6は発熱体電極 3に電流を印加する信号発生 以後の説明の前提として、 熱誘起圧力波発生において成り立つ性質、 すなわち、 In these figures, 1 is a substrate, 2 is a heat insulating layer, 3 is a heating element electrode, 4 is a wiring to a heating element electrode 3, 5 is an acoustic horn, and 6 is a signal for applying a current to the heating element electrode 3. The premise of the explanation is that the property that holds in the generation of heat-induced pressure waves,
「発生する音波の音圧 P ( ω ) は、 投入する電力 q ( ω) に比例し、放射面での 音響ィンピーダンスが等しければ、 単位面積に投入される電力と発生する音波の 音圧 Ρ ( ω ) の比は周波数に依らず等しい」 ことを既知とする。 "The sound pressure P (ω) of the generated sound wave is proportional to the input power q (ω), and if the acoustic impedance at the radiation surface is equal, the power input to the unit area and the sound pressure of the generated sound wave Ρ The ratio of (ω) is equal regardless of frequency. ”
そのとき、 発熱体電極 3の直径を dとし、 その発熱体電極 3に q CW/m2 〕 なる電力を投入したときに、音響ホーン 5の根元で発生した音圧が P = a q C P a〕 であったとすると、 これをそのまま 1 /nにスケールダウンし、 周波数を n 倍にしたとき発生する音圧 P ' は、 Ρ' = q' At this time, the diameter of the heating element electrode 3 is d, and when a power of q CW / m 2 ] is applied to the heating element electrode 3, the sound pressure generated at the root of the acoustic horn 5 is P = aq CP a). If this is scaled down to 1 / n as it is and the frequency is increased by n times, the sound pressure P 'generated Ρ '= q'
であるから、 もし投入する電力を一定に保ち、 q' =n2 qとすると、 放射され る音響パワーの総量は、 Therefore, if the input power is kept constant and q '= n 2 q, the total amount of radiated sound power is
ζ ά2 P' 2 /n2 p c = n2 (π ά2 Ρ2 / ρ c ) ζ ά 2 P ' 2 / n 2 pc = n 2 (π ά 2 Ρ 2 / ρ c)
となり、 スケールダウンする前の η 2 倍になる。 And η 2 times before the scale down.
したがって、 発熱体電極 3の面積を微小化することにより、 同じ投入パワーに 対する音響ゾ ヮ一は増大する。  Therefore, by reducing the area of the heating element electrode 3, the acoustic volume for the same input power increases.
次に、 第 2図 （a) に示すように、一定振幅 Aの電力を投入する代わりに、 第 2図 （b) に示すように、 電力投入を行う時間を全体の lZk倍にし、 振幅を k 倍にすると、 平均投入パワーは変化しない。 ところが、 電力を投入している瞬間 における発生音のパワーは k 2 倍になるから、 発生音のパワーの時間平均は、Next, as shown in Fig. 2 (a), instead of supplying power with a constant amplitude A, the power supply time is increased by lZk times as shown in Fig. 2 (b), and the amplitude is increased. When k times, the average input power does not change. However, since the power of the generated sound at the moment that powers up is doubled k, the time average of the power of the generated sound is
( 1/k) k2 =k (1 / k) k 2 = k
のように k倍になる。 It becomes k times as follows.
したがって、 第 2図 （a) に対して、第 2図 （b) のような駆動法を行うと、 同じ平均投入電力に対する発生音の平均ノ、ヮ一は k倍となる。  Therefore, when the driving method as shown in Fig. 2 (b) is applied to Fig. 2 (a), the average of the generated sound for the same average input power becomes k times.
また、熱誘起超音波への投入電力 qによる発熱体電極 3表面の温度変化分 To から発生音圧を算出するための等価回路は第 3図のように与えられる。  An equivalent circuit for calculating the generated sound pressure from the temperature change To of the surface of the heating element electrode 3 due to the input power q to the thermally induced ultrasonic wave is given as shown in FIG.
ィンピーダンス Zに、 発熱体電極前面における音響ィンピーダンスを代入する と、 そのとき回路に流れる電流が発熱体電極表面付近での空気の粒子速度、 Zの 両端電圧が発生音圧に相当する。  Substituting the acoustic impedance at the front of the heating element electrode into the impedance Z, the current flowing through the circuit at that time corresponds to the particle velocity of air near the heating element electrode surface, and the voltage across Z corresponds to the generated sound pressure.
等価出力インピーダンスを Z。 = 3 cと書くと （ cは空気の特性インピー ダンス） 、  Z is the equivalent output impedance. = 3 c (where c is the characteristic impedance of air)
\ β \ = \ (C/ωΚγ) 1 ^ 8 5 (a t 1 0 0 kHz)  \ β \ = \ (C / ωΚγ) 1 ^ 8 5 (at 1 0 0 kHz)
程度である。 ここで cは空中の音速、 Cは空気の単位体積あたりの定積熱容量、 It is about. Where c is the speed of sound in the air, C is the constant volume heat capacity per unit volume of air,
Kは空気の熱伝導度、 ァは比熱比 （空気の場合、 約 1. 4) である。 例えば、 周 波数を 1 00 kHzとすれば、 | )S | 8 5である。 K is the thermal conductivity of air, and a is the specific heat ratio (about 1.4 for air). For example, if the frequency is 100 kHz, |) S | 85.
したがって、 音響ホーンの入力部の直径を、 発熱体電極の直径の 1/m (m= Therefore, the diameter of the input part of the acoustic horn should be 1 / m (m =
Γβ=" 5) にすると （面積比がSとなり、 発熱体電極から見たインピーダン スは ;8倍になる。 ただし、 これらの径が音波長より小さい場合） 、 送出される音 波のエネルギーは最大になる。 When Γβ = 5) (the area ratio is S, the impedance seen from the heating element electrode is; 8 times. However, when these diameters are smaller than the sound wavelength), the sound to be transmitted is Wave energy is maximized.
なお、 上記した実施例によって、 空間的、 時間的にエネルギーを集中させると、 やがて発熱体電極の許容できる電流値や温度を超えてしまう。 この制限のもとで さらに発生音圧を増大させるには、以下のような発熱体電極の構造を用いればよ い。  According to the above-described embodiment, when energy is concentrated spatially and temporally, the current value and the temperature that can be tolerated by the heating element electrode will eventually be exceeded. To further increase the generated sound pressure under this restriction, the following structure of the heating element electrode may be used.
第 4図は本発明の実施例を示す発熱体電極の変形例の模式図であり、 第 4図 (a) には鋸歯形状発熱体電極の例を、 第 4図 （b) には溝付き形状発熱体電極 の例を、 第 4図 （c) には溝内に配置される分割発熱体電極の例をそれぞれ示し ている。  FIG. 4 is a schematic view of a modified example of the heating element electrode showing the embodiment of the present invention. FIG. 4 (a) shows an example of a sawtooth-shaped heating element electrode, and FIG. FIG. 4 (c) shows an example of a shaped heating element electrode, and FIG. 4 (c) shows an example of a divided heating element electrode arranged in the groove.
第 1の発熱体電極としては、 第 4図 （a) に示すように、 鋸歯形状基板 7上に 熱絶縁層 8を形成して、 その熱絶縁層 8上に鋸歯形状発熱体電極 9を形成する。 その鋸歯形状発熱体電極 9には信号源 1 ◦が接続される。 1 1は放射される音波 を表している。  As a first heating element electrode, as shown in FIG. 4 (a), a heat insulating layer 8 is formed on a sawtooth-shaped substrate 7, and a sawtooth heating element electrode 9 is formed on the heat insulating layer 8. I do. The sawtooth heating element electrode 9 is connected to a signal source 1 °. 1 1 represents the radiated sound wave.
このようにして、 鋸歯形状発熱体電極 9を形成し、 同じ放射面積に対して空気 と鋸歯形状発熱体電極 9が接する面積を X倍することによって、 発生する音圧は X倍になる。 ただし、 この時の条件は鋸歯の高さが発生音波長よりも十分に小さ い場合である。  In this way, by forming the sawtooth-shaped heating element electrode 9 and multiplying the area where the air and the sawtooth-shaped heating element electrode 9 are in contact with the same radiation area by X times, the generated sound pressure becomes X times. However, the condition at this time is when the height of the sawtooth is sufficiently smaller than the generated sound wavelength.
なお、 この例では鋸歯形状発熱体電極 9として説明したが、 ヒダが形成される のであれば、種々の形状にすることができる。  In this example, the saw-tooth-shaped heating element electrode 9 has been described. However, various shapes can be used as long as folds are formed.
第 2の発熱体電極としては、 第 4図 （b) に示すように、 溝付き形状基板 1 2 の溝の内壁に熱絶縁層 1 3を形成して、 その熱絶縁層 1 3上に溝形状発熱体電極 1 4を形成する。 その溝形状発熱体電極 1 4には信号源 1 5が接続される。 1 6 は放射される音波を表している。  As a second heating element electrode, as shown in FIG. 4 (b), a heat insulating layer 13 is formed on the inner wall of the groove of the grooved substrate 12, and the groove is formed on the heat insulating layer 13. The shape heating element electrode 14 is formed. A signal source 15 is connected to the groove-shaped heating element electrode 14. 16 represents the emitted sound waves.
このような構造でも平面の発熱体電極に比べると発生する音圧を高くすること ができる。  Even with such a structure, the generated sound pressure can be increased as compared with a flat heating element electrode.
第 3の発熱体電極としては、 第 4図 （c) 及び第 5図に示すように、 穴付き形 状基板 1 7の溝の内壁に熱絶縁層 1 8を形成して、 その熱絶縁層 1 8上に分割さ れた溝形状発熱体電極 1 9 a， 1 9 b, 1 9 cを形成する。 これらの分割された 溝形状発秦体電極 1 9 a, 1 9 b, 1 9 cにはそれぞれ信号源 2 0 a, 2 0 b, 0As the third heating element electrode, as shown in FIGS. 4 (c) and 5, a heat insulating layer 18 is formed on the inner wall of the groove of the hole-shaped substrate 17 and the heat insulating layer 18 is formed. The groove-shaped heating element electrodes 19a, 19b, and 19c divided on 18 are formed. Signal sources 20a, 20b, 0
2 0 cが接続される。 1は放射される音波を表している。 20 c is connected. 1 represents the emitted sound wave.
このような構造でも平面の発熱体電極に比べると発生する音圧を高くすること ができる。  Even with such a structure, the generated sound pressure can be increased as compared with a flat heating element electrode.
また、 これらの鋸歯形状発熱体電極の鋸歯の高さや溝形状発熱体電極の溝の高 さが発生音波の波長の半分を超えてしまうと、 それ以上に高い鋸歯や溝を形成し ても効果が低減するが、以下のように構成することで、改善することができる。 この実施例では、 空間を電極で取り囲むように構成することができる。  If the sawtooth height of these sawtooth-shaped heating element electrodes or the groove height of the groove-shaped heating element electrode exceeds half the wavelength of the generated sound wave, it is effective to form even higher sawtooth or grooves. Is reduced, but can be improved by configuring as follows. In this embodiment, the space can be configured to be surrounded by the electrodes.
このように、 分割された孔形状発熱体電極 1 9 a , 1 9 b , 1 9 cのように発 熱体電極を波長以下の大きさで分割し、 それぞれを信号源 2 0 a， 2 O b , 2 0 cで独立に駆動して、 その位相を進行波の位相と一致させるようにすれば、 この 構造を延長することで発熱体電極の面積に比例した強い音圧を得るようにするこ ともできる。  In this way, the heating element electrodes are divided into sub-wavelength sizes like the divided hole-shaped heating element electrodes 19 a, 19 b, and 19 c, and each is divided into signal sources 20 a, 20 O By driving independently at b and 20c and making the phase coincide with the phase of the traveling wave, this structure is extended to obtain a strong sound pressure proportional to the area of the heating element electrode. You can do that too.
第 6図はその他の例を示す分割された平板状発熱体電極の構成図である。  FIG. 6 is a configuration diagram of a divided plate-shaped heating element electrode showing another example.
この例では、 横向き角孔付き基板 3 1の角孔に熱絶縁層 （図示なし） を形成し て、 その角孔の下面にのみ分割された平板状発熱体電極 3 2 a , 3 2 b , 3 2 c を形成する。 これらの分割された平板状発爽体電極 3 2 a , 3 2 b , 3 2 cには 信号源 （図示なし） が接続される。 3 3は放射される音波を表している。  In this example, a heat insulating layer (not shown) is formed in the square hole of the substrate 31 with a horizontal square hole, and the plate-like heating element electrodes 32a, 32b, which are divided only on the lower surface of the square hole. Form 3 2 c. A signal source (not shown) is connected to these divided flat-plate-shaped electrodes 32 a, 32 b, and 32 c. 33 represents the emitted sound wave.
この実施例では、 第 6図に示すように、 一面だけに発熱体電極 3 2 a , 3 2 b , In this embodiment, as shown in FIG. 6, the heating element electrodes 32a, 32b,
3 2 cがあり、 作製がより容易になる。 なお、 基板の間隔が波長と等しくなる場 合には、 各発熱体電極に同一の信号を与えて音波を発生させることができる。 第 7図は本発明の他の実施例を示す熱絶縁構造を示す断面図である。 There is 3 2 c, making it easier to fabricate. If the distance between the substrates is equal to the wavelength, the same signal can be given to each heating element electrode to generate a sound wave. FIG. 7 is a sectional view showing a heat insulating structure according to another embodiment of the present invention.
この実施例では、 固体の膜状の熱絶縁層を用いる代わりに、 第 7図に示すよう に、 基板 4 1上に間隔 wが 1 0 m程度の突起物 4 2を形成し、 その突起物 4 2 で発熱体電極 4 3を支持する。 この発熱体電極 4 3の厚みは 1 0 n m以下程度に して発熱体電極 4 3と基板 4 1との間の絶縁を極めて良好なものにすることによ つて、 単位消費電力あたりの発生音圧パワーを増大することができる。  In this embodiment, instead of using a solid film-like heat insulating layer, as shown in FIG. 7, protrusions 42 with a spacing w of about 10 m are formed on a substrate 41, and the protrusions are formed. 4 2 supports the heating element electrode 4 3. By making the thickness of the heating element electrode 43 about 10 nm or less and making the insulation between the heating element electrode 43 and the substrate 41 extremely good, the noise generated per unit power consumption can be improved. The pressure power can be increased.
.なお、 本発明は上記実施例に限定されるものではなく、本発明の趣旨に基づい て種々の変形が可能であり、 これらを本発明の範囲から排除するものではない。 以上、 詳細に説明したように、 本発明によれば、 熱誘起超音波発生装置の熱誘 起超音波の発生効率と最大発生音圧を飛躍的に向上させることができ、 従来の音 響機器、超音波発生器の性能を上回るだけでなく、強力超音波の新しい応用が可 肯^こなる。 例えば、計測応用だけではなくオーディオ機器や強力超音波の非線形 効果をも利用可能な装置を実現することができる。 It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention. As described above in detail, according to the present invention, the heat induction of the heat induction ultrasonic generator The efficiency of generating ultrasonic waves and the maximum generated sound pressure can be dramatically improved, which not only exceeds the performance of conventional sound equipment and ultrasonic generators, but also enables new applications of powerful ultrasonic waves. Become. For example, it is possible to realize a device that can use not only the measurement application but also the non-linear effects of audio equipment and strong ultrasonic waves.
これによつて、 従来の超音波デゾ イスをより高性能なものに置き換えるだけで なく、 パラメトリックアレイなどの非線形音響素子、 放射圧ァクチユエ一夕、 触 覚ディスプレイなどの新しい応用が可能な超音波発生装置を実現することができ る。 産業上の利用可能性  This not only replaces conventional ultrasonic devices with higher-performance ones, but also generates new ultrasonic waves that can be used in new applications such as nonlinear acoustic elements such as parametric arrays, radiation pressure actuators, and tactile displays. The device can be realized. Industrial applicability
本発明の熱誘起圧力波発生装置は、 熱誘起超音波の発生効率と最大発生音圧を 飛躍的に向上させることができ、 音響機器、 超音波発生器のみならず、 パラメ ト リックアレイなどの非線形音響素子、 放射圧ァクチユエ一夕、 触覚ディスプレイ などの超音波発生装置として利用可能である。  The heat-induced pressure wave generator of the present invention can dramatically improve the heat-induced ultrasonic wave generation efficiency and the maximum generated sound pressure, and can be used not only for acoustic equipment and ultrasonic generators, but also for parametric arrays and the like. It can be used as an ultrasonic generator such as a non-linear acoustic element, a radiation pressure actuator, and a tactile display.

Claims

請 求 の 範 囲 The scope of the claims
1 . 基板と、該基板上に設けられる熱絶縁層と、該熱絶縁層上に設けられ、 電 気的に駆動される発熱体電極とを具備する熱誘起圧力波発生装置において、 前記発熱体電極の面積を小さくするとともに、前記発熱体電極に印加する電流 を、 短い時間にパワーが集中している周期的あるいは非周期的ノ、"ルス状あるいは バースト波状にすることによって、 時間平均投入電力に対する発生音の時間平均 パワーを高めることを特徴とする熱誘起圧力波発生装置。 1. A heat-induced pressure wave generator including a substrate, a heat insulating layer provided on the substrate, and an electrically driven heating element electrode provided on the heat insulating layer; By reducing the area of the electrode and making the current applied to the heating element electrode periodic or aperiodic, in which the power is concentrated in a short time, a loose or burst waveform, the time-average input power A heat-induced pressure wave generator characterized by increasing the time-average power of the sound generated from the heat.
2 . 基板と、該基板上に設けられる熱絶縁層と、該熱絶縁層上に設けられ、電 気的に駆動される発熱体電極とを具備する熱誘起圧力波発生装置において、 前記 発熱体電極の面積を小さくするとともに、前記発熱体電極に音響ホーンを接続し、 送出される音のパヮ一を増大させることを特徴とする熱誘起圧力波発生装置。 2. A heat-induced pressure wave generator including a substrate, a heat insulating layer provided on the substrate, and an electrically driven heating element electrode provided on the heat insulating layer; A thermally-induced pressure wave generator, characterized in that the area of the electrode is reduced and an acoustic horn is connected to the heating element electrode to increase the transmitted sound power.
3 . 請求項 2記載の熱誘起圧力波発生装置において、 前記音響ホーンは、 熱誘 起超音波の実効放射ィンピーダンスと整合した音響ホ一ンであることを特徴とす 3. The heat-induced pressure wave generator according to claim 2, wherein the acoustic horn is an acoustic horn matched with the effective radiation impedance of the thermally induced ultrasonic wave.
4 . 請求項 1又は 2記載の熱誘起圧力波発生装置において、前記発熱体電極の 形状をヒダ状となし、前記発熱体電極が空気に接する面積を大きくし、強力な圧 力波を発生させることを特徴とする熱誘起圧力波発生装置。 4. The heat-induced pressure wave generator according to claim 1 or 2, wherein the heating element electrode is formed in a fold shape, the area of the heating element electrode in contact with air is increased, and a strong pressure wave is generated. A heat-induced pressure wave generator characterized by the above-mentioned.
5 . 請求項 1又は 2記載の熱誘起圧力波発生装置において、 前記発熱体電極を 前記基板に形成される溝又は孔の内壁に形成し、前記発熱体電極が空気に接する 面積を大きくし、 強力な圧力波を発生させることを特徴とする熱誘起圧力波発生  5. The heat-induced pressure wave generator according to claim 1, wherein the heating element electrode is formed on an inner wall of a groove or a hole formed in the substrate, and an area where the heating element electrode is in contact with air is increased. Thermally induced pressure wave generation characterized by generating strong pressure waves
6 . 請求項 5記載の熱誘起圧力波発生装置において、 前記発熱体電極を分割し、 該分割された電極を所定の方向に進行する進行波と同期したタイミングで駆動す ることによつて強力な圧力波を発生させることを特徴とする熱誘起圧力波発生装 6. The heat-induced pressure wave generator according to claim 5, wherein the heating element electrodes are divided, and the divided electrodes are driven at a timing synchronized with a traveling wave traveling in a predetermined direction. Heat-induced pressure wave generator characterized by the generation of complex pressure waves
7 . 請求項 5記載の熱誘起圧力波発生装置において、 前記溝又は孔は円柱形状 又は角柱形状の溝又は孔であり、 該溝又は孔の内壁に複数の発熱体電極を配置し、 前記円柱形状又は角柱形状の溝又は孔の長手方向に進行する波動に同期したタイ ミングで前記複数の発熱体電極を駆動することによって、 前記円柱形状又は角柱 形状の溝又は孔の長手方向に進行する強力な圧力波を発生させることを特徴とす る熱誘起圧力波発生装置。 7. The heat-induced pressure wave generator according to claim 5, wherein the groove or hole is a cylindrical or prismatic groove or hole, and a plurality of heating element electrodes are arranged on an inner wall of the groove or hole; Ties synchronized with the waves traveling in the longitudinal direction of the groove or hole A heat-induced pressure wave generator characterized by generating a strong pressure wave that travels in the longitudinal direction of the cylindrical or prismatic groove or hole by driving the plurality of heating element electrodes by means of ming.
8 . 請求項 1又は 2記載の熱誘起圧力波発生装置において、前記発熱体電極を 微小な多数の突起物により支えることによって、 前記基板と発熱体電極の間の熱 絶縁を行うことを特徴とする熱誘起圧力波発生装置。  8. The heat-induced pressure wave generator according to claim 1, wherein the heat-generating electrode is supported by a large number of minute projections, thereby performing thermal insulation between the substrate and the heat-generating electrode. Heat-induced pressure wave generator.
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