J. Inst. Electrostat. Jpn.

⺰ᢥ

論文

静電気学会誌, 29, 1 (2005) 2-7yyන⋧੤ᵹ㔚࿶ߦࠃࠆᶧṢߩ㕒㔚ᠲ૞ァ ม ᣽ ⑲㧖,1㧘ਛ ⷏ ඳ ᤘ㧖㧖㧘㣐 ᵤ ᱜ ᄦ㧖㧔2004 ᐕ 8 ᦬ 23 ᣣฃઃ, 2004 ᐕ 11 ᦬ 6 ᣣฃℂ㧕

Droplet Actuation Based on Single-phase Electrostatic Excitation
Masahide GUNJI*,1, Hiroaki NAKANISHI** and Masao WASHIZU*(Received August 23,2004; Accepted November 6,2004)

A new concept of electrostatic droplet actuation based on field-induced deformation of the droplet is presented in thispaper. The device consists of a diagonal fishbone-shaped electrode array with a hydrophobic coating. When energizedwith an AC voltage, a droplet dispensed on the electrode undergoes a periodical motion of flattening and restoring thespherical shape, and because of the geometrical asymmetry of the electrodes, its center of mass is shifted bit by bit ineach cycle. The actuation speed as high as 2.4 cm/s is achieved for a 1PL-droplet on a 240 Pm-pitch electrode arraywith 50 Hz, 50 Vrms excitation. Droplet sorting and mixing are also demonstrated by bifurcating and merging
electrode arrays. The method only requires a pair of planar electrodes that can be fabricated by a single-mask process,and a single-phase power supply, leading to a simple and low-cost droplet-based micro-chemical system.
1.

߳ߣャㅍߐࠇࠆ.ห᭽ߦ෻ᔕ⹜⮎߽ᶧṢߩᒻߢャㅍߐࠇ,วᵹߪߓ߼ߦ

ൻቇ࡮↢ൻቇಽᨆࠪࠬ࠹ࡓࠍ 1 ᨎߩ࠴࠶ࡊ਄ߦ㓸Ⓧൻߔࠆ,ὐߢ⹜ᢱᶧṢߣⲢวߔࠆ.ߘߩᓟ,⹜⮎ߣⲢวߒߚ⹜ᢱᶧṢߪP-TAS(Micro-Total Analysis System)ߣ๭߫ࠇࠆࠪࠬ࠹ࡓߪ,⹜೎ߩ႐ᚲߦ⸳⟎ߐࠇߚฦ⒳ಽᨆ࠮ࡦࠨ࡯߿෻ᔕࡊࡠ࠮ࠬ㗔ᢱ߿⹜⮎ߩᓸ㊂ൻ,ಽᨆߩ㜞ㅦൻ,ⵝ⟎ߩዊဳൻ࡮ࡠ࡯ࠦࠬ࠻

ၞ߳ಽጘߐࠇ,ಽᨆ߿෻ᔕ߇ⴕࠊࠇࠆ.
਄⸥ߩࠃ߁ߥඨ㐿᡼♽ಽᨆⵝ⟎ࠍታ⃻ߔࠆߚ߼ߦߪ,”ၮ᧼ൻߥߤࠍน⢻ߦߔࠆ߽ߩߣߒߡ,ㄭᐕ,ᕆㅦߦ⎇ⓥ߇ㅴ߼ࠄࠇ
1)

ߡ޿ࠆ .⃻࿷ߩP-TAS ⎇ⓥߦ߅޿ߡߪ,ࠟ࡜ࠬ߿ࠪ࡝ࠦࡦၮ

਄ߩ⋡⊛ߩ૏⟎ߦㄦㅦ਌ߟᱜ⏕ߦᶧṢࠍャㅍߔࠆᛛⴚ” ߩታ᧼ਛߦᓸ⚦ߥᵹ〝ࠍ૞ᚑߒ,ࡐࡦࡊ߿ࡃ࡞ࡉߦࠃࠆᯏ᪾⊛ߥ⃻߇ᔅⷐਇนᰳߣߥࠆ.ߎࠇ߹ߢߩߣߎࠈ,ၮ᧼਄ߢߩᶧṢャᵹ૕೙ᓮ߿㔚᳇ᵒേ,㔚᳇ᶐㅘᵹߣ޿ߞߚ㔚᳇⊛ᚻᴺࠍ↪޿ㅍᛛⴚߦߟ޿ߡᐞߟ߆ႎ๔ߐࠇߡ߅ࠅ,଀߃߫,ၮ᧼਄ߦࡑࠗߡ,ᵹ〝ਛߢᶧ૕⹜ᢱߩ෻ᔕ߿ಽᨆࠍⴕ߁㐽㎮ဳߩಽᨆࠪࠬࠢࡠࡅ࡯࠲࡯ࠕ࡟ࠗࠍ૞ᚑߒ,ߎࠇࠍ↪޿ߡၮ᧼਄ߦ᷷ᐲ൨࠹ࡓߩ㐿⊒߇ਥᵹߣߥߞߡ޿ࠆ.ߒ߆ߒߥ߇ࠄ,ߎߩࠃ߁ߥ㐽㈩ࠍ⊒↢ߐߖࠆߎߣߢၮ᧼਄ߩᶧṢߦࡑ࡜ࡦࠧ࠾ലᨐࠍᒁ㎮ဳࠪࠬ࠹ࡓߦߪ,㐿᡼♽ߢߩᠲ૞߇ⴕ߃ߥ޿,ㅪ⛯ߒߚᵹ〝߈⿠ߎߒᶧṢࠍ᷷ᐲߩૐ޿㗔ၞ߳⒖േߐߖࠆᛛⴚ 2)߿,ၮ᧼਄ߩਛߢߩᵹ૕ߩ৻ㇱߛߌࠍേ߆ߔߎߣ߇࿎㔍,࠺࠶࠼ࡏ࡝ࡘߦశ෻ᔕᕈߩ᦭ᯏ᧚ᢱࠍႣᏓߒ,ᶧṢࠍ⒖േߐߖߚ޿㗔ၞߦ࡯ࡓ߇ߐߌࠄࠇߥ޿ߣ޿ߞߚ໧㗴ὐ߇޽ࠆ.

⚡ᄖ✢ࠍᾖ኿ߒߡ,ၮ᧼⴫㕙ࠍㇱಽ⊛ߦⷫ᳓ൻߔࠆߎߣߦࠃ৻ᣇ,ߎࠇࠄߩ໧㗴ࠍ⸃᳿ߔࠆ߽ߩߣߒߡ,ᵹ〝ߢቢోߦⷒࠅ,ᶧṢࠍャㅍߐߖࠆᛛⴚ 3)ߥߤ߇ႎ๔ߐࠇߡ޿ࠆ߇,ߎࠇࠄߞߡߒ߹ࠊߥ޿ᒻ,ߔߥࠊߜඨ㐿᡼♽ߢᶧ૕⹜ᢱ߿⹜⮎ࠍᶧߩᣇᴺߪᶧṢߩャㅍㅦᐲ߇ 1~2 cm/min ߣㆃߊ,ㄦㅦߥಽᨆ߿

Ṣߩᒻߣߒߡᛒ߁ࠪࠬ࠹ࡓ߽ឭ᩺ߐࠇߡ޿ࠆ.࿑ 1 ߦඨ㐿᡼෻ᔕࠍⴕ߁ߦߪਇะ߈ߢ޽ࠆ.

♽ࠪࠬ࠹ࡓࠍ↪޿ߚᶧṢ⹜ᢱߩ෻ᔕ࡮ಽᨆࡊࡠ࠮ࠬߩ᭎ᔨ࿑ߎߩࠃ߁ߥ⢛᥊ߩਅ,╩⠪ࠄߩ⎇ⓥࠣ࡞࡯ࡊߪ,ၮ᧼਄ߩࠬ

ࠍ␜ߔ.ၮ᧼਄ߦಽᨆ߿෻ᔕߩኻ⽎ߣߥࠆ⹜ᢱᶧṢ߇૞ᚑ࡮㈩࠻࡝࠶ࡊ⁁㔚ᭂߦ㔚࿶ࠍශടߒߡᶧ૕ߦ௛ߊ⺃㔚ᵒേജߦ⟎ߐࠇ,ߎߩᶧṢ߇ャㅍ〝ߦᓥߞߡઁߩ⹜⮎ᶧṢߣߩวᵹὐࠃࠅ㔚ᭂߦᴪߞߚേ߈ࠍ૞ࠅ,ߎࠇߦࠃࠅᶧ૕ߩ㚟േ࡮ᶧṢൻ߿ᷙวࠍⴕ߁ᚻᴺࠍ㐿⊒ߒߚ 4)-8).ߒ߆ߒߥ߇ࠄ,ߎߩ⺃㔚ᵒേࠠ࡯ࡢ࡯࠼㧦Droplet actuation, Electro wetting, Micro-TAS* ᧲੩ᄢቇᎿቇ♽⎇ⓥ⑼ᯏ᪾Ꮏቇኾ᡹㧔113-8656 ᧲੩ㇺᢥ੩඙ᧄㇹ 7-3-1㧕
Department of Mechanical Engineering, The University ofTokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan㧚** (ᩣ) ፉᵤ⵾૞ᚲ (604-8511 ੩ㇺᏒਛ੩඙⷏ࡁ੩᪀ේ↸ 1)
Shimadzu Corporation, 1 Kuwabara-cho, Nakagyo-ku, Kyoto
604, Japan1gunji@washizu.t.u-tokyo.ac.jpജࠍ೑↪ߒߚᶧ૕ᠲ૞ᴺߦߪ,⹜ᢱߩዉ㔚₸߇㜞ߊߥࠆߣᶧ
૕ౝߩ⊒ᾲ߇ᄢ߈ߊߥࠅ,㚟േ߇࿎㔍ߦߥࠆߣ޿߁໧㗴ὐ߇޽ࠅ,ᛒ߁ߎߣߩ಴᧪ࠆᶧ૕ߩ⒳㘃߇ᄢ᏷ߦ㒢ቯߐࠇߡߒ߹
߁.
߹ߚ Electrowetting ࠍ೑↪ߒߡ,࠲ࠗ࡞⁁ߦ૞ࠄࠇߚ㔚ᭂ㈩೉ߦ㗅ᰴ㔚࿶ࠍශടߒߡ x-y ᐔ㕙਄ߩછᗧߩ૏⟎ߦᶧṢࠍ⒖േߐߖࠆᚻᴺ 9)߿㧘⴫㕙ࠍ⇹᳓ൻߒߚᄙ⋧㔚ᭂࠍၮ᧼਄ߦ㈩-単相交流電圧による液滴の静電操作（軍司昌秀ら）
න⋧੤ᵹ㔚࿶ߦࠃࠆᶧṢߩ㕒㔚ᠲ૞㧔ァมࠄ㧕

3ߦኻߒ㧘⸃᡼ߐࠇࠆࠨࠗࠢ࡞ߢߪ╬ᣇ⊛ߦ⃿ᒻߦㄭ޿ᒻߦᚯ೉ߒ,୘‫ߩޘ‬㔚ᭂߦ㔚࿶ࠍ㗅ᰴශടߒߡ޿ߊߎߣߦࠃࠅᶧṢ10)߽ႎ๔ߐࠇߡ޿ࠆ߇,޿ߕࠆ.ᰏᱤ⁁㔚ᭂ߇ㅴⴕᣇะߦኻߒߡr45qߩ㕖ኻ⒓ߥᒻࠍߒ

ࠇߩᚻᴺߦ߽,㔚᳇⊛⚿✢߇ⶄ㔀ߦߥࠅ,ᄙጀ㈩✢ᛛⴚࠍ↪޿ߡ޿ࠆߚ߼㧘ᄌᒻࠨࠗࠢ࡞߇↢ߕࠆߚ߮ߦ㧘ᶧṢߪ⒖േߒ߿ࠆᔅⷐ߇޽ࠆߣ޿ߞߚ໧㗴ὐ߇ሽ࿷ߔࠆ.

ߔ޿ᣇะ߳ߣ⒖േߒߡ޿ߊߎߣߦߥࠆ.ߔߥࠊߜ,ߎߩࠗࡦ࠴

ࠍォ߇ࠆࠃ߁ߦ⒖േߐߖࠆᚻᴺࡢ࡯ࡓࡔࠞ࠾࠭ࡓߦࠃࠅ,ᶧṢߪ৻ᣇะ㧔࿑ਛߩฝ஥߆ࠄᏀ੹࿁╩⠪ࠄߪ,ၮ᧼਄ߦࡄ࠲࡯࠾ࡦࠣߐࠇࠆ㔚ᭂߩᒻ⁁ࠍ஥㧕߳ߣャㅍߐࠇࠆߎߣߦߥࠆ.

Ꮏᄦߒ㔚ᭂ਄ߩᶧṢߦ㕒㔚ᒁജߦࠃࠆࠗࡦ࠴ࡢ࡯ࡓㆇേࠍ⺃⿠ߐߖࠆߎߣߢ,න⚐ߥනጀ㈩✢,න⋧੤ᵹ㔚࿶ߢߩᶧṢߩ㚟േࠍน⢻ߦߔࠆᚻᴺࠍᣂߚߦ㐿⊒ߒߚ.ᧄⓂߢߪߎߩᚻᴺ
ߩၮᧄේℂߣ,ߐࠄߦߎࠇࠍ↪޿ߚᶧṢಽጘ,วᵹ࠺ࡃࠗࠬ߳

਄㕙࿑Aߩᔕ↪ࠍႎ๔ߔࠆ.
2.

㔚ᭂᢿ㕙࿑ A-A’⛘✼ጀ

45q-45qᶧṢャㅍ㔚ᭂ࠺ࠩࠗࡦߣャㅍේℂ

࿑ 2 ߦ੹࿁૞ᚑߒߚᶧṢャㅍ㔚ᭂߩ࠺ࠩࠗࡦࠍ␜ߔ.ࡈࠜ

㔚ᭂ࠻࡝࠰ࠣ࡜ࡈࠖ࡯ᛛⴚࠍ↪޿ߡᐔမߥၮ᧼਄ߦ৻ኻߩᰏᱤ

ၮ᧼A’⁁㔚ᭂ߇ᶧṢㅴⴕᣇะߦኻߒr45qߩⷺᐲߢะ߆޿วߞߡ

⇹᳓ᕈ⊹⤑(࠹ࡈࡠࡦ)ࡄ࠲࡯࠾ࡦࠣߐࠇߡ߅ࠅ,㔚ᭂ਄ߦߪ⛘✼ጀߣߒߡ SiO2 ጀ߇
ၸⓍߐࠇߡ޿ࠆ.ߐࠄߦၮ᧼਄ߪ࠹ࡈࡠࡦࠦ࡯࠹ࠖࡦࠣߦࠃ

࿑ 2 ᶧṢャㅍ㔚ᭂ࠺ࠩࠗࡦࠅ⇹᳓ಣℂ߇ᣉߐࠇࠆ.

Fig.2 The design of droplet actuator.

⛯޿ߡߎߩ㔚ᭂࠍ↪޿ߚᶧṢャㅍߩේℂࠍ␜ߔ.߹ߕߪ
㔚ᭂၮ᧼਄ߦᶧṢࠍ㈩⟎ߔࠆ(࿑ 3-a).ߎߩᤨ,ၮ᧼਄ߪ࠹ࡈࡠ

(a) 㔚࿶ශട೨
਄㕙࿑ࡦߦࠃࠆ⇹᳓ᕈಣℂ߇ᣉߐࠇߡ޿ࠆߚ߼,ᶧṢߩ૕Ⓧ߇ࡑࠗࠢࡠ࡝࠶࠻࡞ࠝ࡯࠳࡯ߣ޿ߞߚචಽዊߐ޿႐วߦߪ,ၮ᧼਄ߩᶧṢᒻ⁁ߪ߶߷⃿ᒻࠍ଻ߟ.ߘߩᓟ,㔚ᭂ㑆ߦ੤ᵹ㔚࿶ࠍශAടߔࠆߣ,ᶧṢߣ㔚ᭂ㑆ߦ⊒↢ߔࠆ㕒㔚ᒁജߦࠃࠅ,ᶧṢߪ㔚ᭂ਄ߦᒁ߈ነߖࠄࠇ,㔚⇇߇ᦨᄢߣߥࠆ੤ᵹ㔚࿶ߩࡇ࡯ࠢઃ

ᢿ㕙(A-A’)A’ᶧṢㄭߢߪᶧṢ߇ᚳᐔൻߒ(࿑ 2-b)㧘߹ߚ㔚࿶߇ 0V ߦߥࠆ⍍㑆ઃㄭߢߪᄌᒻ߇㔚⇇߆ࠄ⸃᡼ߐࠇ⃿⁁ߦ߽ߤࠆࠃ߁ߥᝄേࠍ(b) ੤ᵹ㔚࿶ࡇ࡯ࠢᤨ

↢ߕࠆ(࿑ 2-c).ߎߩᤨ,ᚳᐔൻߩ↢ߓࠆࠨࠗࠢ࡞ߢߪ,ᰏᱤ⁁㔚ᭂߩࠛ࠶ࠫߩ૞ࠆ㔚⇇㓸ਛߦࠃࠅ,ᰏᱤࠍ⿧߃ߚᄌᒻ߇↢ߓߦߊߊ,࿑ 2-b ߩࠃ߁ߦᶧṢߪ㔚ᭂߦᴪߞߚᒻ⁁ߦᄌᒻߔࠆߩ
⹜⮎ AᶧṢೋᦼ૏⟎

path A(c) ੤ᵹ㔚࿶ 0V ઃㄭᶧṢ⹜ᢱ
path B⹜⮎ B: ᶧṢャㅍ〝

ᝄേ 1 ࠬ࠹࠶ࡊಽߦ߅ߌࠆᶧṢߩᄌ૏

࿑ 1 ඨ㐿᡼♽ᓸዊಽᨆⵝ⟎ߩ᭎ᔨ࿑࿑ 3 ࠗࡦ࠴ࡢ࡯ࡓㆇേߦࠃࠆᶧṢャㅍේℂ

Fig.1 Schematic image of droplet-based micro reactor.

Fig.3 The mechanism of droplet movement.

- 2 -

4

静電気学会誌3.

第 29 巻

第 1 号（2005）4.

ᰏᱤဳ㔚ᭂߦࠃࠆᶧṢߩャㅍታ㛎⠨ኤ

4.1࿑ 4 ߦታ㓙ߦ૞ᚑߐࠇߚᰏᱤဳ㔚ᭂࠍ↪޿ߡᶧṢߩャㅍࠍᶧṢߩ⒖േㅦᐲ

ⴕߞߚᤨߩ᭽ሶࠍ␜ߔ.ߎߩᤨ૞ᚑߒߚᰏᱤ㔚ᭂࡇ࠶࠴ߪ 240ᧄ⎇ⓥߢ↪޿ߚࠗࡦ࠴ࡢ࡯ࡓࡔࠞ࠾࠭ࡓߦࠃࠆᶧṢߩ⒖

Pm ߢ,ᰏᱤ㔚ᭂ 1 ᧄߩ᏷ߣᰏᱤ㑆㓒ߪߘࠇߙࠇ 120Pm,ኻะߔേㅦᐲߪ,㧔ᶧṢߩᝄേ㧝ࠬ࠹࠶ࡊ޽ߚࠅߩ⒖േ〒㔌㧕㧔ᄌࠆᰏᱤ㔚ᭂ㑆ߩࠡࡖ࠶ࡊߪ 30Pm ߢ޽ࠆ.߹ߚ⛘✼ጀߩෘߐߪᒻࠨࠗࠢ࡞ߩ๟ᵄᢙ㧕ߦࠃߞߡ᳿ቯߐࠇࠆ.

⚂ 1Pm,࠹ࡈࡠࡦߩࠬࡇࡦࠦ࡯࠻ߦࠃࠆ⇹᳓ࠦ࡯࠻ߩෘߐߪ

ߎߩ㧝ࠬ࠹࠶ࡊ޽ߚࠅߩ⒖േ〒㔌ߪ,ᄌᒻߩᄢ߈ߐߦଐሽ

⚂ 0.1Pm ߢ޽ࠆ.

ߒ,㔚ᭂࡇ࠶࠴ߩᢛᢙ୚ߣߥࠆ.ߔߥࠊߜ,㔚ᭂߦ㔚࿶߇චಽߦ

㔚ᭂ਄ߦ૕Ⓧ 1PL ߩ⫳⇐᳓ࠍṢਅߒ(࿑ 4-a),๟ᵄᢙ 50Hz ߩශടߐࠇߥ޿ߣ੤ᵹ㔚࿶ࡇ࡯ࠢᤨߦ߅ߌࠆᶧṢߩᄌᒻ㊂߇੤ᵹ㔚࿶ࠍᓢ‫ߦޘ‬ශടߒߚߣߎࠈ,ᶧṢߪ㕒㔚ᒁജߦࠃࠅߘ

㔚ᭂࡇ࠶࠴ࠍ⿧߃ࠆߎߣ߇಴᧪ߕ,ᶧṢߩ⒖േߪ⊒↢ߒߥ޿ߩ႐ߢᝄേࠍᆎ߼,㔚࿶߇⚂ 50Vrms ߦ㆐ߒߚߣߎࠈߢᶧṢߪ߇,ㅒߦශട㔚࿶߇චಽߦ㜞ߌࠇ߫,ᶧṢߦᄢ߈ߥᄌᒻ߇↢ߓ,ᝄേࠍ઻޿ߥ߇ࠄ࿑ਛ⍫ශߢ␜ߐࠇࠆ㔚ᭂ㐳ᚻᣇะߦᴪߞ

㔚ᭂࡇ࠶࠴㧝ߟએ਄ߩ⒖േࠍ↢ߕࠆߎߣ߽น⢻ߢ޽ࠆ.

ߡ⒖േߒ(࿑ 4-b),㔚ᭂ⚳┵ߦ㆐ߔࠆߣ⒖േࠍ஗ᱛߒߚ(࿑ 4-c).

߹ߚ,ᶧṢߩᄌᒻߪශട㔚⇇ߣᶧṢߦ⺃ዉߐࠇࠆ㔚⩄ߩ⋧ߎߩᤨߩᶧṢߩ⒖േㅦᐲߪ⚂ 2.4 cm/s ߢ޽ߞߚ.

੕૞↪ߦࠃߞߡ↢ߓࠆߚ߼,ᄌᒻߪ੤ᵹ㔚࿶ߩඨ๟ᦼ޽ߚࠅ 1
࿁,ߔߥࠊߜᄌᒻࠨࠗࠢ࡞ߩ๟ᵄᢙߪ,ශട๟ᵄᢙߩ㧞୚ߣߥࠆ.

(a)࿑ 5 ߪᰏᱤ㔚ᭂ਄ߢߩᶧṢߩ⒖േߩ᭽ሶࠍ,㜞ㅦᐲࠞࡔ࡜ᶧṢࠍ↪޿ߡ஥㕙߆ࠄⷰኤߒߚ߽ߩߢ޽ࠆ.ߎߩᤨශടߒߚ੤ᵹ
㔚࿶ߩ๟ᵄᢙߪ 50Hz ߢ,㔚࿶ߩᄢ߈ߐߪᶧṢߩ⒖േ߇⊒↢ߔࠆᦨዊߩ㔚࿶ߢ޽ࠆ 50Vrms,ᰏᱤ㔚ᭂߩࡇ࠶࠴ߪ 240Pm ߢ޽ࠆ.ᶧṢߩᄌᒻࠨࠗࠢ࡞ߪ 10ms㧔๟ᵄᢙ 100Hz㧕ߢ,ᝄേ㧝ࠨࠗࠢ࡞Ფߦ㔚ᭂࡇ࠶࠴ 1 ߟಽ(240Pm)ߕߟ⒖േߒߡ޿ࠆ᭽ሶ

1mm߇ⷰኤߐࠇߚ.
4.2

ᶧṢߩᄌᒻ㊂ߩ๟ᵄᢙଐሽᕈ

਄⸥ߩࠃ߁ߦ,ࠗࡦ࠴ࡢ࡯ࡓࡔࠞ࠾࠭ࡓ߇↢ߕࠆߚ߼ߦߪ,(b)ᶧṢߩᄌᒻ߇޽ࠆ⒟ᐲએ਄ᄢ߈޿ߎߣ߇ᔅⷐߢ޽ࠆ.৻⥸ߦ,ᤨ㑆ߣߣ߽ߦᄌൻߔࠆᄖജߦࠃࠆᶧṢߩᄌᒻߪ,ᶧ૕ߩ⴫㕙ᒛജ߅ࠃ߮⾰㊂ߦࠃߞߡᡰ㈩ߐࠇࠆᒝ೙ᝄേߣߥࠅ,޽ࠆ๟ᵄᢙߢ౒ᝄ߇߅߈ࠆ.ᓥߞߡ,ᶧṢߩᄌᒻࠍᄢ߈ߊߣࠆߦߪ,♽ߩ࿕᦭ᝄേߣ౒ᝄߔࠆࠃ߁ߦශട๟ᵄᢙࠍㆬ߱ߎߣ,ߔߥࠊߜ,㧔㔚Ḯ๟ᵄᢙ㧕㧩㧔ᶧṢߩ࿕᦭๟ᵄᢙ㧕¸㧞,ߣߥࠆࠃ߁
ߦㆬ߱ߎߣ߇᦭ലߢ޽ࠆ.
ߎߩᝄേߩ࿕᦭๟ᵄᢙ fc ߪ,ⓨ㑆ਛߦቅ┙ߒߚඨᓘ a ߩ⃿ᒻᶧ૕☸ሶߦኻߒߡ,(c)fc

1 ( n  1) n ( n  2) J2S
U a3

(1)

ߢਈ߃ࠄࠇࠆ 11).ߎߎߢ,n ߪࡕ࡯࠼ᢙ,Uߪᶧ૕ߩኒᐲ,Jߪ⴫㕙ᒛജߢ޽ࠆ.
ᑼ(1)ߪ,ᦨૐᰴߩࡕ࡯࠼ n=2,૕Ⓧ 2PL ߩ᳓ߦኻߒߡ fc = 17ශട㔚࿶:~50 Vrms, ๟ᵄᢙ:50 Hz,6 Hz ࠍਈ߃ࠆ.৻ᣇ,࿑ 6 ߪ,㔚ᭂ਄ߦ߅޿ߡᶧṢࠍ㚟േߐߖࠆ㔚ᭂࡇ࠶࠴:240Pm, ⒖േㅦᐲ:~2.4 cm/s

ߚ߼ߩᦨૐ㔚࿶ߩ᷹ቯ୯ࠍ๟ᵄᢙߦኻߒߡࡊࡠ࠶࠻ߒߚ߽

࿑ 4 ᰏᱤ㔚ᭂ਄ߢߩᶧṢャㅍߩ᭽ሶߩߢ(૶↪ߒߚᰏᱤ㔚ᭂߩࡇ࠶࠴ߪ 240Pm,SiO2 ⛘✼ጀߩෘߐFig.4 Droplet movement on the fish-bone electrode.

ߪ 5Pm),60 Hz ઃㄭߢᦨ߽ૐ޿㔚࿶ߢᶧṢ߇㚟േߢ߈ࠆߎߣ
- 3 -単相交流電圧による液滴の静電操作（軍司昌秀ら）

5න⋧੤ᵹ㔚࿶ߦࠃࠆᶧṢߩ㕒㔚ᠲ૞㧔ァมࠄ㧕ࠍ␜ߒߡ޿ࠆ.ᑼ(1)ߪⓨ㑆ਛߦቅ┙ߒߚ⃿ࠍႺ⇇᧦ઙߦ↪޿㪊㪌㪇ߡ⸘▚ߒߚ႐วߩ୯ߢ,ታ㛎ߦ߅޿ߡߪᶧṢ߇ 105º ⒟ᐲߩធ㪊㪇㪇㔚࿶㩿㪭㫉㫄㫊㪀⸅ⷺࠍ߽ߞߡၮ᧼ߦ⟎߆ࠇߡ޿ࠆߎߣࠍ⠨ᘦߔࠇ߫,ߎߩ୯ߪ,fc / 2 = 88 Hz ߣᲧセ⊛⦟޿৻⥌ࠍ␜ߒߡ޿ࠆߣ⠨߃ࠄࠇࠆ.

㪉㪌㪇㪉㪇㪇
㪈㪌㪇㪈㪇㪇

⒖േߩ⊒↢ߔࠆ๟ᵄᢙᏪ㪌㪇㪇㪇

(a)

㪉㪇㪋㪇

㪍㪇㪏㪇㪈㪇㪇㔚Ḯ๟ᵄᢙ㩿㪟㫑㪀
࿑ 6 㚟േᦨૐ㔚࿶ߣ㔚Ḯ๟ᵄᢙߩ㑐ଥ
Fig.6 Measured minimum voltage for droplet actuation.

5.

1mm

ᶧṢャㅍ〝ߩಽጘ,ววᵹ߳ߩᔕ↪

ߎࠇ߹ߢ⚫੺ߒߚャㅍ㔚ᭂࠍ⚵ߺวࠊߖࠆߎߣߢᶧṢt = 0ャㅍ〝ߩಽጘ࡮วᵹ߇น⢻ߦߥࠆએਅߦߎࠇࠄߩ㔚ᭂߦߟ޿ߡ⺑᣿ߔࠆ
5.1(b)

ᶧṢಽጘ㔚ᭂ

࿑ 7,8 ߪᶧṢಽጘ㔚ᭂ࠺ࠩࠗࡦߣታ㓙ߦᶧṢಽጘ㔚ᭂࠍ↪
޿ߚᶧṢャㅍߩ᭽ሶߢ޽ࠆ.3 ⚵ߩᶧṢャㅍ㔚ᭂࠍ Y ሼဳߦ⚵ߺวࠊߖࠆߎߣߢᶧṢߩㅴ〝ࠍ 1 ߟߩ౉ࠅญ㧔࿑ਛฝ㧕߆ࠄ
2 ߟߩ಴ญ㧔࿑ਛᏀ਄,Ꮐਅ㧕ߩ޿ߕࠇ߆߳ಽጘߐߖࠆ.ᶧṢࠍ㔚ᭂ౉ࠅญߦ㈩⟎ߒ,࿑ 8-a,b ߦ␜ߐࠇࠆࠃ߁ߦ౉ࠅญ஥ߩャㅍ㔚ᭂߣ಴ญB ஥ߩャㅍ㔚ᭂߦ੤ᵹ㔚࿶ࠍශടߔࠆ(๟ᵄᢙ50 Hz, ශട㔚࿶ 50 Vrms).ߔࠆߣᶧṢߪ㔚ᭂ౉ࠅญ߆ࠄಽጘ

t = 5 msὐߦ㆐ߒߚᓟߦ(࿑ 8-b),㔚࿶ߩශടߐࠇߡ޿ࠆ಴ญ B ߩャㅍ㔚ᭂ߳ߣ஍ะߐࠇߚ(࿑ 8-c).

(c)5.2240 PmᶧṢวᵹ㔚ᭂߐࠄߦߎߩᶧṢಽጘ㔚ᭂߦ߅޿ߡ,㔚ᭂࡄ࠲࡯ࡦࠍ೨ᓟㅒォߔࠆߎߣߢ,ᶧṢߩㅴⴕᣇะࠍ෻ォߐߖࠇ߫,2 ߟߩᶧṢߩㅴ〝ࠍ 1 ߟߩㅴ〝ߦวᵹߐߖࠆᶧṢวᵹ㔚ᭂࠍ૞ᚑߔࠆߎߣ
߇಴᧪ࠆ.࿑ 8 ߦᶧṢวᵹ㔚ᭂߩ࠺ࠩࠗࡦࠍ␜ߔ.࿑ 9 ߦታ㓙ߦ૞ᚑߒߚᶧṢวᵹ㔚ᭂࠍ↪޿ߡ,೎‫ߩޘ‬ャㅍ㔚ᭂߦ㈩⟎ߐࠇߚ㧞ߟߩᶧṢࠍ 1 ߟߩャㅍ㔚ᭂߦวᵹߐߖߚᤨߩ᭽ሶࠍ␜t = 10 ms

ߔ.A,B2 ߟߩ౉ࠅญ(࿑ 9 ฝ,ਅ)ߦ⫳⇐᳓(૕Ⓧ 1PL)ࠍ㈩⟎ߒ,࿑ 9-a ߦ␜ߐࠇࠆࠃ߁ߦ 3 ⚵ߔߴߡߩャㅍ㔚ᭂߦ੤ᵹ㔚࿶ࠍ㔚࿶๟ᵄᢙ 50 Hz, ᶧṢᝄേ๟ᦼ 10 msශടߔࠆ(๟ᵄᢙ 50 Hz, ශട㔚࿶ 50 Vrms).ߔࠆߣ౉ࠅญ A,B ߦ㈩⟎ߐࠇߚᶧṢߪ㔚ᭂਛᄩߩวᵹὐࠍㅢߓߡ㔚ᭂ಴ญߦ࿑ 5 㜞ㅦᐲࠞࡔ࡜ߦࠃࠆᶧṢᒻ⁁ᄌൻߩⷰኤ

ャㅍߐࠇ(࿑ 9-b),ᦨ⚳⊛ߦ 2 ߟߩᶧṢ߇㔚ᭂ಴ญ⚳ὐߦ߅޿Fig.5 Time sequence of droplet movement recorded withߡⲢวߒߚ(࿑ 9-c).

a high-speed camera.

- 4 -6

静電気学会誌

第 29 巻

第 1 号（2005）

಴ญ಴ญ AวᵹὐಽጘὐᶧṢೋᦼ૏⟎ AᶧṢೋᦼ૏⟎౉ญ A,B౉ญᶧṢೋᦼ૏⟎ B಴ญ B
࿑ 7 ᶧṢಽጘ㔚ᭂ࠺ࠩࠗࡦ

࿑ 9 ᶧṢวᵹ㔚ᭂ࠺ࠩࠗࡦ

Fig.7 The design of droplet sorter.

Fig.9 The design of droplet mixer.

಴ญ A(a)

ಽጘὐᶧṢ

(a)

౉ญ౉
ญ

วᵹὐ

౉ญ

2mm

಴ญ

౉
ญ
A2mm2mm
಴ญ B

ᶧṢ

(b)

౉ญ B(b)(c)(c)Ⲣวߒߚ 2 ߟߩᶧṢ

࿑ 8 ᶧṢಽጘ㔚ᭂߦࠃࠆᶧṢㅴ〝ߩಽጘ

࿑ 10 ᶧṢวᵹ㔚ᭂߦࠃࠆャㅍ〝ߩวᵹ

Fig.8 Droplet sorting using bifurcating electrode array.

Fig.10 Droplet mixing using merging electrode array.

- 5 -単相交流電圧による液滴の静電操作（軍司昌秀ら）

7න⋧੤ᵹ㔚࿶ߦࠃࠆᶧṢߩ㕒㔚ᠲ૞㧔ァมࠄ㧕6.

ቇ⋭⑼ቇ⎇ⓥ⾌⵬ഥ㊄(ၮ⋚⎇ⓥ A14205037)ߩഥᚑࠍฃߌⴕ

߹ߣ߼ࠊࠇ߹ߒߚ.

ඨ㐿᡼♽ᓸዊಽᨆࠪࠬ࠹ࡓታ⃻ߩߚ߼ߩᣂߚߥᶧṢャㅍ
ᣇᴺߣߒߡ,㔚ᭂᒻ⁁ࠍᶧṢㅴⴕᣇะߦኻߒߡ㕖ኻ⒓ߥᒻߦ

߹ߚ,㔚ᭂࡄ࠲࡯࠾ࡦࠣߩߚ߼ߩࡑࠬࠢߪ᧲੩ᄢቇᄢⷙᮨߔࠆߎߣߢ,㔚ᭂ਄ߩᶧṢߦࠗࡦ࠴ࡢ࡯ࡓㆇേࠍᒁ߈⿠ߎߒ,㓸Ⓧࠪࠬ࠹ࡓ⸳⸘ᢎ⢒⎇ⓥ࠮ࡦ࠲࡯(VDEC)ߩ EB ឬ↹ⵝ⟎ߎࠇߦࠃࠅᶧṢࠍ㔚ᭂ਄ߩ⋡⊛ߩ૏⟎߳ߣャㅍߔࠆᣇᴺࠍࠍ↪޿ߡ⵾૞ߐࠇ߹ߒߚ.

㐿⊒ߒ,ታ㓙ߦߎࠇࠍ↪޿ߡන⋧੤ᵹ㔚࿶ߦࠃࠆᶧṢߩャㅍෳ⠨ᢥ₂Micro Total Analysis Systems 2002 (Kluwer AcademicPublishers, 2002)
2) Y.T.Tseng, F.G.Tseng, Y.F.Chen and C.C.Chieng: Sens.
Actuators A, 114, (2004) 292
3) K.Ichimura, S.K.Oh and M.Nakagawa: Science, 288 (2000)
16244) M.Gunji, T.B.Jones and M.Washizu: Proc. IEJ-ESA Joint
Symposium on Electrostatics, pp.78-87 (2000)
5) T.B.Jones, M.Gunji, M.Washizu and M.J.Feldman: J. Appl.
Phys., 89 (2001) 1441
6) M.Gunji, T.B.Jones and M.Washizu: Technical Digest ofMEMS2001, pp.385-388 (2001)7) ァม᣽⑲, T.B.Jones, 㣐ᵤᱜᄦ: 㕒㔚᳇ቇળ⻠Ṷ⺰ᢥ㓸’02, pp.155-158 (2002)8) ァ ม ᣽ ⑲ , 㣐 ᵤ ᱜ ᄦ : 㕒 㔚 ᳇ ቇ ળ ⻠ Ṷ ⺰ ᢥ 㓸 ’03,pp.123-128 (2003)
9) J.Lee, H.Moon, J.Fowler, T.Schoellhammer and C.-J.Kim:
Sens. Actuators A, 95 (2002) 259
10) M.Washizu: IEEE Trans. Ind. Appl., 34(4) (1998) 732
11) H. Lamb: Hydrodynamics 6th Edition, Cambridge University
Press (1975)ߦᚑഞߒߚ.

1)ߐࠄߦߎߩᶧṢャㅍ㔚ᭂࠍ⚵ߺวࠊߖࠆߎߣߢ,1 ᧄߩᶧṢャㅍ〝ࠍ 2 ᧄߩᶧṢャㅍ〝߳ಽጘߐߖߚࠅ,2 ᧄߩᶧṢャㅍ〝ࠍ㧝ᧄߩᶧṢャㅍ〝߳วᵹߐߖࠆ,ᶧṢಽጘ࡮วᵹ㔚ᭂࠍ㐿⊒ߒߚ.
ᧄ⎇ⓥߢ㐿⊒ߐࠇߚᶧṢャㅍ࡮ಽጘ࡮วᵹ㔚ᭂࠍ⚵ߺวࠊߖࠆߎߣߢ,ᶧṢ⹜ᢱߩャㅍ߿,ઁߩ⹜⮎ߣߩᷙว,෻ᔕᶧṢߩಽ೎,ߐࠄߦߪ೎ߩಽᨆⵝ⟎߳ߩዉ౉ߣ޿ߞߚಽᨆ࡮෻ᔕࡊࡠ
࠮ࠬߦᔅⷐߥᠲ૞ࠍၮ᧼਄ߢⴕ߁ߎߣ߇น⢻ߣߥࠆ.

ᧄ⎇ⓥࠍⴕ߁ߦ޽ߚࠅ,᦭⋉ߥ⼏⺰ߣߏഥജࠍ㗂޿ߚ᧲ർ
ᄢቇߩᎹ㊁⡡ᕶᢎ᝼㧘᧲੩ᄢቇߩਛየ᡽ਯᢎ᝼ߦኻߒᔃࠃࠅ
⻢ᗧࠍ⴫ߒ߹ߔ. ᧄ⎇ⓥߩ৻ㇱߪ↢⎇࠮ࡦ࠲࡯(BRAIN),ᣣᧄቇⴚᝄ⥝ળ⑼ቇ⎇ⓥ⾌⵬ഥ㊄(⺖㗴⇟ภ 16-61612)෸߮,ᢥㇱ⑼- 6 -