JP2004265665A - Field emission type electrode, its manufacturing method, and equipment using field emission type electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a field emission type electrode in which a tape-like material including a CNT is adhered to a substrate simply and at a low cost without impairing the electron discharge characteristics of CNT and without requiring a special equipment, and provide its manufacturing method, and an equipment using the field emission type electrode. <P>SOLUTION: A tape-like material including CNT is interposed between a pair of substrates, and after pressurization, it is separated, and a tape shape peeled substance is adhered on the substrate and this is made a field emission type electrode. Furthermore, a tape-like material is interposed between a substrate and a substrate having higher ductility than the substrate, and after pressurization, it is separated, and a tape shape peeled substrate is adhered to the substrate, and this is made a field emission type electrode. Then, using the field emission type electrode, an electric equipment or an electronic equipment is formed and furthermore, an equipment or a plant is formed by incorporating the electric equipment or electronic equipment. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２６】
［実施の形態３］
（電子機器等）
本発明に係るＣＮＴを含むテープ状物質を貼り付けた電界放出用電極は、ＣＮＴの純度も高く、かつ、１本１本のＣＮＴがその細束性を維持した状態で、均一な薄い膜状に貼られているので、電極加熱用の電源を必要とせず、また従来のものより、より低い電圧で多くの電子を引き出せるので、それを用いた「電気機器または電子機器」は、省エネ化、小型化、低コスト化、高出力化を達成できる。
【００２７】
すなわち、ＣＮＴを含むテープ状物質は、ＣＮＴの純度も高く、かつ、合成されたままの状態、つまり１本１本のＣＮＴが互いに部分的にしか接しておらず、その細束性を維持した状態で、均一な薄い膜状であるので、そのまま基板に押し付けて引き離すだけで、高性能の電界放出型電極として用いることができる。
たとえば、電界放出用電子源として、蛍光表示管やフィールドエミッションディスプレイ（ＦＥＤ）などの陰極材料および電子顕微鏡の探針などへの利用が考えられている。
とくに、テープ状物質を基板に押し付けて付着すれば、その後の表面処理等は不要であるため、製造工程ならびに製造コストの低減を図ることができる。
【００２８】
一方、従来の電子源は、熱電子放出型が主流であり、これは、電子放出を行わせるために電子源を加熱する必要があった。そのために、加熱用の電源が必要であり、装置が大型かつ複雑になると共に、消費電力も大きいものであった。また、電界放出型の電子源としては、針状金属を用いたものおよびＣＮＴを用いたものがあるが、金属製のものは耐久性に問題があり、寿命の低いものであった。
また、ＣＮＴは炭素からできているので耐熱性および導電性に優れ、耐久性において金属に勝るが、従来のものでは、先に述べたように、細束性を維持した状態で、均一に基板や電極上に貼付けることは難しく、高い電界強度を与えなければ電界放出させることはできなかった。そのため、高電圧の電源装置を用意しなければならず、装置が大型かつ高価なものになっていた。
【００２９】
［実施の形態４］
（プラント等）
本発明に係るＣＮＴを含むテープ状物質を貼り付けた電界放出用電極を用いた電気機器または電子機器を組み込んだ「装置およびプラント」は、従来にない省エネ化、小型化、低コスト化、高出力化を達成できる。
放電機器を組み込んだ装置およびプラントは、オゾナイザー、空気清浄装置、イオン発生装置、Ｘ線発生装置、水質浄化プラント、土壌浄化プラント、プラズマリアクター、コピー機、薄型テレビなど数多いが、放電機器の性能が、これら装置およびプラントの性能を決定する最重要項目である。
従来は、放電機器の高消費電力、大型、高コスト、小出力電流のため、放電機器を組み込んだこれら装置およびプラントのコストパフォーマンスは低いものであった。
【００３０】
［テープ状物質（実施の形態１〜４に共通）］
本発明におけるテープ状物質（ＣＮＴを含むテープ状物質）は、極度に集中して安定したアーク放電を達成することによって合成されたものであって、従来にない、高純度のＣＮＴが密集したものである。
【００３１】
すなわち、アーク放電を起こすためには、電極間空間を電離する必要がある。原子の電離には、種々の過程があるが、アーク放電においては、電子との衝突による電離過程が支配的である。
一般に、原子番号の小さいＨｅ、Ｎｅを除き、Ａｒ、Ｋｒ、Ｘｅなどの不活性ガスは、酸素、窒素等に比べて電子との衝突による電離能率が高く、アークを発生しやすい空間を提供する。
したがって、これらの不活性ガスもしくは不活性ガスを含む混合ガスをプラズマガスとして供給しながらアーク放電を行うと、アークは該プラズマガスのガス流路に沿って集中して発生することになる。
つまり、陽極電極から陰極電極に向けて前記プラズマガスを噴出することによって、アークを集中させ、陰極点を安定化させることができる。
【００３２】
さらに、発明者は種々の検討の結果、高純度のＣＮＴを効率よく合成するためには、ＣＮＴが生成される陰極表面上のアーク発生点における温度履歴が重要であること、すなわち、該温度履歴が常に同一となるように電極を相対移動することが必須であることを見出した。
換言すると、ＣＮＴが生成される陰極の温度を適正な温度範囲に保つことが重要であって、移動するアーク発生点を基準にした場合、時間に無関係な一様な温度場が実現される準定常状態とするように電極を相対移動させることが必要である。そして、かかる知見に基づいて適正な温度履歴が得られる電極の相対移動をすることによって、ＣＮＴの純度ならびに収量の増加がほぼ全線にわたり得られる。
【００３３】
たとえば、幅ならびに厚さの略一定な平板上を直線的に重ならないようにして移動させたり、円柱もしくは円筒状陰極の側面を螺旋状に重ならないようにして移動させる方法が良い。これらの方法によると、アークの発生開始位置と終了位置付近を除き、ほぼ一定な温度履歴をアーク発生点は受けることになり、アーク発生点を適正な温度履歴とすることができる。
さらに、ＣＮＴが十分に成長する条件下では、従来見られなかった高純度のＣＮＴが密集したテープ状物質を連続して合成することが可能となる。また、このテープ状物質は、テープ状のまま陰極から引き剥がすことが可能であるので、回収が至って容易である。
【００３４】
（実施例）
図８および図９は本発明に係る電界放出型電極の実施の形態２〜４におけるテープ状物質を合成する一実施例を説明する模式図であって、図８は合成状況、図９は合成後の状況である。
図８の（ａ）は側面視、（ｂ）は平面視である。図８において、筒状陽極１の貫通孔１ａから陰極２に向けて放電用ガス４を吹き出しながら、筒状陽極１を一方向に移動してアーク放電を行っている。合成条件は、たとえば、（１）筒状陽極１：外径１０ｍｍで内径４ｍｍの筒状炭素材料、
（２）陰極２：板状炭素材料（抵抗値３５００μΩ・ｃｍ）、
（３）雰囲気：開放空間すなわち大気圧下で大気雰囲気、
（４）放電用ガス４：３％の水素を含むアルゴンガス、１リットル／分の流量（筒状陽極１の貫通孔１ａから陰極２に向けて吹き出し）、
（５）アーク放電：電流１００Ａ、電圧２０Ｖ（アーク長約１ｍｍ）にて１分間アーク放電、
（６）陽極移動速度：１０ｃｍ／分、である。
このとき、陰極２の表面２ａに帯状に堆積物５（以下、陰極堆積物と称す）が付着し、陰極堆積物５は中央部のテープ状物質１０とその両側の付着物質６とによって構成されている。
テープ状物質１０はアーク３の中心部３ａ（陰極点に同じ）が走査した経路に帯状に合成され、アーク放電後の冷却（自然冷却または強制冷却）によって陰極２の表面２ａから容易に剥離するものである。このテープ状物質１０を走査型電子顕微鏡（ＳＥＭ）および透過型電子顕微鏡（ＴＥＭ）により観察したところ高純度のＣＮＴの集合体で構成されていることが判明した
一方、付着物質６はアモルファスカーボンであった。
【００３５】
テープ状物質１０は静止アークの場合と同様に合成されるものであって、アーク３の中心部３ａにＣＮＴが合成され、その周辺部にアモルファスカーボンが堆積するものである。このため、陽極１を移動すると、アーク３の移動に伴ってＣＮＴが生成され易い条件も一緒に移動する。
このとき、アーク３が近づくとアーク３の周辺部にアモルファスカーボン６が堆積し、ここに、アーク３が到達すると、既に堆積しているアモルファスカーボン６の上にＣＮＴが合成され易い条件（アーク３の中心部３ａに同じ）ができるから、ここにＣＮＴが合成される。
さらに、アーク３の中心部が去っていくと、合成されたＣＮＴの位置においてＣＮＴが合成され易い条件が崩れるため、合成したＣＮＴの上にアモルファスカーボン６が堆積することになる。
よって、アーク３の移動によって、ＣＮＴは上下左右の面をアモルファスカーボン６に包囲されたテープ状に形成される。
さらに、アーク３が過ぎ去った後、アモルファスカーボン６は高温の状態で大気と触れ合うため、酸化・燃焼して一部が焼失し、その後、陰極堆積物５が低温になると、テープ状物質１０とアモルファスカーボン６との熱膨張率の相違により、テープ状物質１０が剥離する現象が起っている（図９参照）。
なお、剥離したテープ状物質１０の上面（陽極側）は、堆積したアモルファスカーボン６の一部が焼失するため、下面（陰極側）に比較してアモルファスカーボン６の付着量が少なく純度の高いものになっている。
【００３６】
【発明の効果】
以上のように本発明によれば、ＣＮＴ繊維が具備する特性を損なうことなく、特別の装置を必要としないで簡単安価に、テープ状物質（ＣＮＴを含むテープ状物質）が付着された電界放出型電極とその製造方法、および該電界放出型電極を用いた電気機器または電子機器、並びに該電気機器または電子機器を組み込んだプラントを得ることができる。
【図面の簡単な説明】
【図１】本発明に係る電界放出型電極の製造方法の実施の形態１を説明する模式図である。
【図２】本発明に係る電界放出型電極の実施の形態１を説明する模式図である。
【図３】図１に示す製造方法における、基板と引き剥がされたテープ状物質の接合面近傍の電子顕微鏡写真である。
【図４】図１に示す製造方法における、テープ状物質が引き剥がされた引き剥がし面を示す上から見た電子顕微鏡写真である。
【図５】図１に示す製造方法における、テープ状物質１０が引き剥がされた引き剥がし面を示す垂直に切断した電子顕微鏡写真である。
【図６】本発明に係る電界放出型電極の製造方法の実施の形態２を説明する模式図である。
【図７】本発明に係る電界放出型電極の製造方法の実施の形態２における他の製造方法を説明する模式図である。
【図８】本発明に係る電界放出型電極の実施の形態２〜４におけるテープ状物質を合成する一実施例の合成状況を説明する模式図である。
【図９】本発明に係る電界放出型電極の実施の形態２〜４におけるテープ状物質を合成する一実施例の合成後の状況を説明する模式図である。
【符号の説明】
１０ テープ状物質、 １１ テープ状剥離物質、
１２ テープ状剥離物質、 ２１ 基板、
２２ 基板、 ２３ 変形板、
４１ 電界放出型電極、 ４２ 電界放出型電極、
４３ テープ状物質付着変形板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a field emission electrode using carbon nanotubes, particularly to a field emission electrode using a tape-like substance containing high-purity carbon nanotubes, a method for manufacturing the same, and a device using the field emission electrode.
[0002]
[Prior art]
(carbon nanotube)
Carbon nanotubes are mainly produced by a vapor deposition method (CVD method) or an arc discharge method, and are formed by rolling a sheet in which carbon atoms are regularly arranged in a hexagonal shape (hereinafter, referred to as a graphene sheet) into a cylindrical shape. Because of its unique properties, it is attracting attention as a new material.
A single graphene sheet tube is called a single-walled carbon nanotube (SWCNT), and its diameter is 1 to several nm. On the other hand, a graphene sheet in which multiple cylinders are concentrically overlapped is referred to as a multi-walled carbon nanotube (MWCNT) and has a diameter of several nm to several tens nm. Further, at both ends of the carbon nanotube, there are a carbon nanotube which is closed in a substantially conical shape by adding a pentagonal shape to a part of a hexagonal array of carbon atoms, and a carbon nanotube which is cut off in a cylindrical shape.
[0003]
In the present invention, SWCNT and MWCNT are collectively referred to as carbon nanotubes (hereinafter, referred to as CNTs), and a single CNT is a “CNT fiber”, an aggregate including the CNT fibers, and a tape-like structure. Those having a thickness of, for example, 10 to 500 μm, a width of 1 to 10 mm, and an arbitrary length are referred to as “a tape-like substance containing CNT (sometimes simply referred to as a tape-like substance)”.
[0004]
CNT has very high field emission characteristics, and is used for a field emission cold cathode device material such as a fluorescent display tube, an X-ray tube, and a field emission display (FED) (referred to as a field emission electrode in the present invention). ) Is being considered for practical use.
A technique necessary for practical use is to adhere CNT to an electrode substrate (hereinafter, referred to as a substrate) while maintaining high electron emission characteristics.
For example, a paste containing CNTs (to be precise, a bundle paste in which a bundle composed of a plurality of CNTs aggregated in a viscous solution having conductivity) is printed on a substrate by pattern printing, and is applied to the surface of the pattern. The paste is removed by laser irradiation. As a result, a technique for exposing CNT has been disclosed (for example, see Patent Document 1).
Further, a paste containing CNTs is printed on a substrate by pattern printing, an adhesive layer is formed on the surface of the pattern, and the adhesive layer is peeled off, whereby the paste layer is delaminated. As a result, a technique for exposing CNTs to a peeled surface having irregularities has been disclosed (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP-A-2000-36243 (page 4, FIG. 1)
[Patent Document 2]
JP-A-2003-16911 (page 3, FIG. 3)
[0006]
[Problems to be solved by the invention]
However, the technique disclosed in Patent Literature 1 uses a bundle that is a structure in which CNTs are oriented in substantially the same direction, and thus it is difficult to stably synthesize the bundle. Since the laser irradiation process is performed, there is a problem that a manufacturing apparatus becomes expensive or complicated.
Further, the technique disclosed in Patent Literature 2 uses a paste to adhere CNTs to a substrate, so that the conductivity between the CNTs and the substrate may not be guaranteed in some cases. Since it is difficult to uniformly disperse CNTs therein, there is a problem that CNTs on a substrate having a pattern printed on the substrate cannot be uniformly increased in density.
[0007]
The present invention has been made to solve such a problem, and a tape-like substance containing CNT can be easily and inexpensively attached to a substrate without impairing the electron discharge characteristics of the CNT and without requiring any special device. It is an object of the present invention to provide a field emission electrode, a method of manufacturing the same, and a device using the field emission electrode.
[0008]
[Means for Solving the Problems]
The field emission electrode according to the present invention is as follows.
(1) A tape-like substance containing carbon nanotubes is sandwiched between a pair of substrates facing each other, separated by pressing, and the tape-like substance peeled off is attached to the substrate. Things.
[0009]
(2) The tape-like substance containing the carbon nanotube is sandwiched between a substrate and a substance having a higher deformability than the substrate, and the tape-like substance peeled off after being pressed is adhered to the substrate. It is characterized by the following.
(3) In the above (2), the tape-like substance containing the carbon nanotube is synthesized by an arc discharge method, and is sandwiched such that the surface on the anode side at the time of the synthesis touches the substrate.
[0010]
Devices using the field emission electrode according to the present invention are as follows.
(4) An electric or electronic device using the field emission electrode according to any one of (1) to (3).
(5) An apparatus and a plant incorporating the electric device or the electronic device according to (4).
[0011]
Further, a method for manufacturing a field emission electrode according to the present invention is as follows.
(6) A tape-like substance containing carbon nanotubes is sandwiched between a pair of substrates facing each other, separated by pressing, and the tape-like substance peeled off is attached to the substrate. is there.
(7) sandwiching a tape-like substance containing carbon nanotubes between a substrate and a substance having a higher deformability than the substrate, separating the tape-like substance after pressing, and attaching the peeled tape-like substance to the substrate. It is a feature.
(8) In the above (7), the tape-like substance containing the carbon nanotube is synthesized by an arc discharge method, and is sandwiched such that the surface on the anode side at the time of the synthesis touches the substrate.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
[Embodiment 1]
(Method of manufacturing field emission electrode)
FIG. 1 is a schematic diagram illustrating Embodiment 1 of a method for manufacturing a field emission electrode according to the present invention. In FIG. 1, reference numeral 10 denotes a tape-like substance containing CNT (hereinafter, referred to as a tape-like substance), and reference numerals 21 and 22 denote substrates.
First, a tape-like or sheet-like tape-like substance 10 having a thickness of about 50 to 500 μm is disposed between a pair of substrates 21 and 22 (FIG. 1A). Next, the tape-shaped substance 10 is sandwiched and pressed (FIG. 1B). Further, the pair of substrates 21 and 22 are separated ((c) in FIG. 1).
At this time, since the tape-like substance 10 is peeled off in two in the thickness direction, the peeled-off tape-like substances 11 and 12 (hereinafter referred to as tape-like peeling substances) adhere to the substrates 21 and 22, respectively. are doing. That is, a field emission electrode 41 is formed by the substrate 21 and the tape-shaped stripping substance 11, and a field emission electrode 42 is formed by the substrate 22 and the tape-shaped stripping substance 12.
Various materials such as conductive metal and non-conductive resin can be used as the substrate material, but metals such as stainless steel, aluminum, copper, tungsten and alloys thereof are used as the substrate material for the field emission electrode. .
[0013]
(Field emission type electrode)
FIG. 2 is a schematic diagram illustrating Embodiment 1 of the field emission electrode according to the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and a part of the description will be omitted.
The tape-like peeling substance 11 adheres to the substrate 21 (adhering surface is assumed to be 11B), and CNT fibers are fluffed on the surface 11T of the tape-like peeling substance 11 (described in detail below).
[0014]
(Joining surface)
FIG. 3 is an electron micrograph of the vicinity of the bonding surface 11B between the substrate 21 and the tape-like release material 11 in the manufacturing method shown in FIG. An adhesive tape is once adhered onto the peeling surface 12T of the tape-like peeling substance 11 obtained by the above processing, then the adhesive tape is peeled off, and the substrate 21 is cut and polished.
According to the results of elemental analysis, it was confirmed that the white part in the center of the photograph was the CNT fiber and the lower part was the aluminum substrate, and most of the CNT fiber was on the surface of the substrate 21 when peeled off with an adhesive tape. Remains on top.
That is, it is shown that the CNT fiber and the substrate 21 are closely adhered to each other without any gap, and that the bonding strength between the CNT fiber and the substrate is larger than the bonding strength between the CNT fiber and the adhesive tape.
Furthermore, the aluminum substrate before bonding is mirror-finished to a surface roughness of 0.1 μm or less. Since the surface roughness is increased to about several μm as a whole, slight deformation of the substrate occurs due to pressure. Therefore, it is presumed that the contact area with the CNT fiber increases and adheres, and further, the CNT fiber bites into the substrate, so that a so-called mechanical bonding state also exists.
Therefore, the mechanism for attaching the CNTs to the substrates 21 and 22 is that a part of the CNTs enters the unevenness of the material surface of the substrates 21 and 22 by pressurization and generates a binding force by mechanically catching, that is, a so-called bonding force is generated. Anchor mechanism (mechanical bonding), the same effect caused by the deformation of the material surfaces of the substrates 21 and 22 and the penetration of the CNTs, and a part of the carbon atoms constituting the CNTs bond with the atoms of the substrates 21 and 22 It is considered that any one of chemical bonding and physical bonding such as van der Waals force or various bonding forces are acting in combination.
[0015]
(Peeling surface)
4 and 5 are electron micrographs showing the peeling surface 11T of the tape-like peeling substance 11 in the manufacturing method shown in FIG. 1, and FIG. 4 shows the peeling surface 11T viewed from above, and FIG. The peeled surface 11T is cut vertically.
4 and 5, a feather-like pattern is observed on the entire surface of the CNT fiber layer. When a portion such as feathers is viewed from the lateral direction, the CNT fibers are fluffy and extend toward the open space. That is, it is estimated that the entangled CNT fibers have been unraveled by the manufacturing method.
That is, each of the CNT fibers constituting the tape-like substance grows in the thickness direction of the tape while being intertwined with each other in a complicated manner, and the CNTs have a property of gathering together when compressed. When pressurized, the CNTs are aggregated, but the aggregated force is weaker than the adhesion to the substrate.
[0016]
Therefore, when the substrates 21 and 22 are separated after being pressurized, the entangled CNT fibers adhering to the substrates 21 and 22 are unraveled (peeled off) from the gathered portions and cut. It is considered that the cut CNT fibers were oriented parallel to the separating direction (perpendicular to the opposing surfaces of the substrates 21 and 22).
In other words, the CNT fibers constituting the tape-like material 10 are separated due to the fact that they are basically grown in the thickness direction of the tape-like material, and the length thereof is sufficiently long and complicatedly entangled. Later, it is presumed that the peeling surfaces 11T and 12T have a fluffy form.
[0017]
Therefore, the conductivity of the adhesion surfaces 11B and 12B between the substrates 21 and 22 and the tape-like release substances 11 and 12 is ensured, and the field emission electrodes excellent in the electron emission characteristics on the separation surfaces 11T and 12T can be easily manufactured. Is done.
That is, since the CNTs can be installed in an electrical device or an electronic device in a state where the CNTs are peeled, the CNTs can be stuck in a form easily exhibiting the characteristics as an electron source by using a tape-like substance in which CNT fibers are densely packed. The attached field emission electrode can be easily manufactured.
[0018]
[Embodiment 2]
(Method of manufacturing field emission electrode)
FIG. 6 is a schematic diagram illustrating Embodiment 2 of the method for manufacturing a field emission electrode according to the present invention. The same parts as those in the first embodiment (FIG. 1) are denoted by the same reference numerals, and a part of the description will be omitted.
In FIG. 6, reference numeral 23 denotes a substance having a higher deformability than the substrate 22 (hereinafter, referred to as a deformed plate). First, the tape-like substance 10 is disposed between the substrate 22 and the deformable plate 23 (FIG. 6A). Next, the tape-shaped substance 10 is sandwiched and pressed (FIG. 6B). Further, the substrate 22 and the deformable plate 23 are separated from each other (FIG. 6C).
[0019]
At this time, since the tape-like substance 10 is peeled off in two in the thickness direction, the tape-like release substances 12 and 13 are attached to the substrate 22 and the deformed plate 23, respectively.
That is, the field emission electrode 42 is formed by the substrate 22 and the tape-like peeling substance 12, and the tape-like substance-attached deformation plate 43 is formed by the deformable plate 23 and the tape-like peeling substance 13.
[0020]
Since the surface of the deformable plate 23 is deformed by pressure, a bulge 24 is formed around the tape-like peeling substance 13 on the surface of the tape-like substance-attached deformable plate 43. That is, when the deformable plate 23 undergoes plastic flow, the pressing force uniformly acts on the entire surface of the substrate 22. As a result, it is possible to obtain a more uniform CNT adhesion surface 12B without adhesion unevenness.
In particular, even when the surface of the substrate 22 is not perfectly smooth, the pressing force acts uniformly on any of the relatively protruding portion and the relatively depressed portion of the substrate 22, so that uniform adhesion is obtained. can get. Therefore, when peeled, the adhesion surface 12B does not partially peel from the surface of the substrate 22. That is, conductivity on the attachment surface 12B is guaranteed.
When the tape-shaped material 10 is synthesized by arc discharge, the surface of the tape-shaped material 10 located on the anode side has a stronger adhesive force to the substrate than the surface on the cathode side (the cathode electrode side of the tape-shaped material is However, the carbon material of the cathode is slightly attached and the purity of the CNT is lower than that of the anode side. This will be described separately). In addition, the deformable plate 23 having higher deformability has a stronger adhesive force than the substrate 22. For this reason, if the surface on the anode side of the tape-like substance 10 is disposed on the substrate 22 side and the surface on the cathode side is disposed on the deformable plate 23 side, the adhesion strength on each surface becomes substantially equal (the difference between them becomes small), In addition, it is possible to obtain a more uniform CNT adhesion surface 12B without adhesion unevenness on the substrate 22.
[0021]
Various materials such as a conductive metal and a non-conductive resin can be used as the material of the substrate 22, but metals such as stainless steel, aluminum, copper, and tungsten are used as the substrate material for the field emission electrode. An alloy is used.
For example, when the substrate 22 is a stainless disk (for example, a diameter of 5 mm), an indium block can be used as the deformable plate 23. Similar results were obtained using lead, solder, aluminum and the like.
[0022]
(Other manufacturing methods for field emission electrodes)
FIG. 7 is a schematic view for explaining another manufacturing method according to the second embodiment of the method for manufacturing a field emission electrode according to the present invention. The same parts as those in FIG. 6 are denoted by the same reference numerals, and a part of the description will be omitted.
In FIG. 7A, the shape of the substrate 22, the deformed plate 23, and the tape-like material 10 in plan view are substantially the same, and the female mold 50 (the die) having a through hole having the same shape as the plan view shape is provided. ).
In FIG. 7B, the deformable plate 23 in the female mold 50 is pressed by the punch 60. At this time, since the outer shell of the deformable plate 23 is restrained by the female mold 50 and does not deform in the outer shell direction, the pressing of the tape-like substance 10 is ensured.
In FIG. 7C, when the substrate 22 and the deformed plate 23 are separated from each other, a field emission electrode 42 is formed by the substrate 22 and the tape-like peeling substance 12 attached thereto, as in FIG. The tape-like substance-attached deformation plate 43 is formed by 23 and the tape-like peeling substance 13 attached thereto.
At this time, the deformable plate 23 is not deformed to the outer peripheral side by the pressurization, and the surface thereof is not raised, so that more uniform adhesion is obtained. Usually, the peeling is performed outside the female mold 50.
[0023]
(Field emission type electrode)
The second embodiment of the field emission type electrode according to the present invention is the same as the first embodiment, and the description is omitted.
[0024]
(Field emission characteristics of field emission electrodes)
Table 1 shows a comparison between the field emission characteristics of the field emission electrode according to the present invention and the conventional method. In a vacuum, the field emission electrode was used as a cathode, the distance from the anode was set to 0.1 mm, and a predetermined value was obtained. It is a comparison of applied voltages when a current density (10 mA / cm2) is obtained.
Compared with the conventional method, it has been confirmed that the field emission electrode according to the method of the present invention has a significantly reduced applied voltage when a predetermined current density is obtained, and has an extremely high electron emission ability.
That is, while the paste or tape-like substance containing powdered CNTs is applied with an applied voltage of 680 V or 440 V, a method of sandwiching between substrates or a method of sandwiching between a substrate and a deformed plate is used. The applied voltage is 210 V or 192 V, and the electron emission ability is improved.
[0025]
[Table 1]

[0026]
[Embodiment 3]
(Electronic equipment, etc.)
The field emission electrode to which the tape-like substance containing CNT according to the present invention is applied has a high purity of the CNT and a uniform thin film-like shape in which each CNT maintains its fineness. Since it is affixed to the battery, it does not require a power supply for heating the electrodes, and it can extract more electrons at a lower voltage than conventional ones. Small size, low cost, and high output can be achieved.
[0027]
That is, the tape-like substance containing CNTs has a high purity of the CNTs and is in a state of being synthesized, that is, each CNT is only partially in contact with each other, and has maintained its fine bundle property. In this state, since the film is uniform and thin, it can be used as a high-performance field emission electrode simply by pressing it against the substrate and pulling it apart.
For example, as a field emission electron source, application to cathode materials such as a fluorescent display tube and a field emission display (FED) and a probe of an electron microscope has been considered.
In particular, if the tape-shaped substance is pressed against and adhered to the substrate, subsequent surface treatment or the like is unnecessary, so that the manufacturing process and the manufacturing cost can be reduced.
[0028]
On the other hand, conventional electron sources are mainly of thermionic emission type, which requires heating the electron source in order to emit electrons. Therefore, a power supply for heating is required, and the apparatus becomes large and complicated, and power consumption is large. In addition, field emission type electron sources include those using needle-like metal and those using CNT, but those made of metal have a problem in durability and have a short life.
Also, CNTs are excellent in heat resistance and conductivity because they are made of carbon, and are superior to metals in durability. However, in the conventional CNT, as described above, the substrate is uniformly maintained while maintaining the fine bundle. And it was difficult to attach it on the electrodes, and it was not possible to emit the electric field unless a high electric field strength was given. Therefore, a high-voltage power supply device must be prepared, and the device is large and expensive.
[0029]
[Embodiment 4]
(Plants, etc.)
The “equipment and plant” incorporating an electric or electronic device using the field emission electrode to which the tape-like substance containing CNT according to the present invention is attached can save energy, miniaturize, reduce cost, and increase cost. Output can be achieved.
There are many devices and plants that incorporate discharge equipment, such as ozonizers, air purifiers, ion generators, X-ray generators, water purification plants, soil purification plants, plasma reactors, copiers, and flat-screen TVs. Are the most important items that determine the performance of these devices and plants.
Conventionally, due to the high power consumption, large size, high cost, and small output current of the discharge equipment, the cost performance of these devices and plants incorporating the discharge equipment has been low.
[0030]
[Tape-like substance (common to Embodiments 1 to 4)]
The tape-like substance (tape-like substance including CNT) in the present invention is synthesized by achieving a stable arc discharge by being extremely concentrated, and is a dense, unprecedented high-purity CNT. It is.
[0031]
That is, in order to cause arc discharge, it is necessary to ionize the space between the electrodes. There are various processes in the ionization of atoms, but in arc discharge, the ionization process due to collision with electrons is dominant.
Generally, except for He and Ne having small atomic numbers, inert gases such as Ar, Kr, and Xe have a higher ionization efficiency due to collision with electrons than oxygen, nitrogen, and the like, and provide a space where arcs are easily generated. .
Therefore, if an arc discharge is performed while supplying these inert gas or a mixed gas containing the inert gas as a plasma gas, the arc is generated intensively along the gas flow path of the plasma gas.
That is, by ejecting the plasma gas from the anode electrode toward the cathode electrode, the arc can be concentrated and the cathode spot can be stabilized.
[0032]
Further, as a result of various studies, the inventors have found that in order to efficiently synthesize high-purity CNTs, the temperature history at the arc generation point on the cathode surface where CNTs are generated is important. It has been found that it is essential to move the electrodes relative to each other so as to always be the same.
In other words, it is important to keep the temperature of the cathode where CNTs are generated in an appropriate temperature range, and when the moving arc generating point is used as a reference, a uniform temperature field independent of time is realized. It is necessary to move the electrodes relatively so as to be in a steady state. Then, the relative movement of the electrode for obtaining an appropriate temperature history based on such knowledge can increase the purity and yield of the CNT over almost the entire line.
[0033]
For example, it is preferable to move on a flat plate having a substantially constant width and thickness so as not to overlap linearly, or to move so that the side surfaces of a column or a cylindrical cathode do not overlap spirally. According to these methods, the arc generation point receives a substantially constant temperature history except near the arc generation start position and the end position, and the arc generation point can be set to an appropriate temperature history.
Furthermore, under conditions where CNTs grow sufficiently, it becomes possible to continuously synthesize a tape-like substance in which high-purity CNTs, which have not been seen before, are densely packed. Further, since this tape-like substance can be peeled off from the cathode in the form of a tape, it is easy to recover.
[0034]
(Example)
8 and 9 are schematic diagrams illustrating an example of synthesizing a tape-like substance in the second to fourth embodiments of the field emission electrode according to the present invention. FIG. 8 shows a synthesis state, and FIG. The latter situation.
8A is a side view, and FIG. 8B is a plan view. In FIG. 8, arc discharge is performed by moving the cylindrical anode 1 in one direction while blowing out the discharge gas 4 from the through hole 1a of the cylindrical anode 1 toward the cathode 2. The synthesis conditions include, for example, (1) cylindrical anode 1: a cylindrical carbon material having an outer diameter of 10 mm and an inner diameter of 4 mm;
(2) Cathode 2: plate-like carbon material (resistance value 3500 μΩ · cm),
(3) Atmosphere: open space, that is, atmospheric atmosphere under atmospheric pressure,
(4) Discharge gas 4: an argon gas containing 3% hydrogen, a flow rate of 1 liter / minute (blows out from the through hole 1a of the cylindrical anode 1 toward the cathode 2),
(5) Arc discharge: arc discharge at a current of 100 A and a voltage of 20 V (arc length of about 1 mm) for 1 minute,
(6) Anode moving speed: 10 cm / min.
At this time, a deposit 5 (hereinafter, referred to as a cathode deposit) adheres to the surface 2a of the cathode 2 in a strip shape, and the cathode deposit 5 is constituted by a tape-like substance 10 at a central portion and adherent substances 6 on both sides thereof. ing.
The tape-like substance 10 is synthesized into a band along the path scanned by the center 3a (same as the cathode point) of the arc 3, and easily peels off from the surface 2a of the cathode 2 by cooling (natural cooling or forced cooling) after the arc discharge. Things. Observation of this tape-like substance 10 with a scanning electron microscope (SEM) and a transmission electron microscope (TEM) revealed that the tape-like substance 10 was composed of a high-purity CNT aggregate.
On the other hand, attached substance 6 was amorphous carbon.
[0035]
The tape-like substance 10 is synthesized in the same manner as in the case of the stationary arc, in which CNT is synthesized at the central portion 3a of the arc 3 and amorphous carbon is deposited on the periphery thereof. For this reason, when the anode 1 is moved, the conditions under which CNTs are likely to be generated are moved together with the movement of the arc 3.
At this time, when the arc 3 approaches, the amorphous carbon 6 accumulates in the peripheral portion of the arc 3. When the arc 3 reaches the arc 3, the CNTs are easily synthesized on the already deposited amorphous carbon 6 (arc 3). CNT is synthesized here.
Furthermore, when the center of the arc 3 leaves, the conditions under which CNTs are easily synthesized at the position of the synthesized CNTs are broken, and the amorphous carbon 6 is deposited on the synthesized CNTs.
Therefore, the CNTs are formed in a tape shape in which the upper, lower, left, and right surfaces are surrounded by the amorphous carbon 6 by the movement of the arc 3.
Further, after the arc 3 has passed, the amorphous carbon 6 comes into contact with the atmosphere in a high-temperature state, so that it is oxidized and burned, and a part thereof is burned off. Due to the difference in the coefficient of thermal expansion from the carbon 6, a phenomenon occurs in which the tape-like substance 10 peels off (see FIG. 9).
The upper surface (anode side) of the peeled tape-like substance 10 has a smaller amount of amorphous carbon 6 attached and a higher purity than the lower surface (cathode side) because part of the deposited amorphous carbon 6 is burned off. It has become.
[0036]
【The invention's effect】
As described above, according to the present invention, the field emission to which the tape-like substance (the tape-like substance including CNT) is attached can be performed simply and inexpensively without deteriorating the characteristics of the CNT fiber, without requiring any special device. It is possible to obtain a mold electrode, a method of manufacturing the same, an electric or electronic device using the field emission electrode, and a plant incorporating the electric or electronic device.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating Embodiment 1 of a method for manufacturing a field emission electrode according to the present invention.
FIG. 2 is a schematic diagram illustrating a first embodiment of a field emission electrode according to the present invention.
FIG. 3 is an electron micrograph showing the vicinity of a bonding surface between a substrate and a peeled tape-like substance in the manufacturing method shown in FIG.
FIG. 4 is an electron micrograph viewed from above showing a peeling surface from which the tape-like substance has been peeled off in the manufacturing method shown in FIG. 1;
5 is a vertically cut electron micrograph showing a peeled surface from which the tape-like substance 10 has been peeled off in the manufacturing method shown in FIG.
FIG. 6 is a schematic view illustrating Embodiment 2 of a method for manufacturing a field emission electrode according to the present invention.
FIG. 7 is a schematic diagram for explaining another manufacturing method according to the second embodiment of the method for manufacturing a field emission electrode according to the present invention.
FIG. 8 is a schematic diagram illustrating a synthesis state of an example of synthesizing a tape-like substance in Embodiments 2 to 4 of the field emission electrode according to the present invention.
FIG. 9 is a schematic diagram illustrating a situation after synthesis of an example of synthesizing a tape-like substance in Embodiments 2 to 4 of the field emission electrode according to the present invention.
[Explanation of symbols]
10 tape-like substance, 11 tape-like release substance,
12 tape-like release material, 21 substrate,
22 substrate, 23 deformed plate,
41 field emission electrode, 42 field emission electrode,
43 Deformation plate with tape-like substance attached

Claims (8)

A field emission type characterized in that a tape-like substance containing carbon nanotubes is sandwiched between a pair of substrates facing each other, separated by pressure, and the tape-like substance peeled off is attached to the substrate. electrode. The tape-like substance containing the carbon nanotubes is sandwiched between a substrate and a substance having a higher deformability than the substrate, and the tape-like substance peeled off after being pressed is attached to the substrate. Field emission electrode. 3. The field emission electrode according to claim 2, wherein the tape-like substance containing the carbon nanotube is synthesized by an arc discharge method, and the anode-side surface at the time of the synthesis is sandwiched so as to contact the substrate. An electric device or an electronic device using the field emission electrode according to claim 1. An apparatus and a plant incorporating the electric device or the electronic device according to claim 4. A tape-like substance containing carbon nanotubes is sandwiched between a pair of substrates facing each other, separated by pressure, and the tape-like substance peeled off is attached to the substrate. Production method. A tape-like substance containing carbon nanotubes is sandwiched between a substrate and a substance having a higher deformability than the substrate, separated after pressing, and the tape-like substance peeled off is attached to the substrate. A method for manufacturing a field emission electrode. 8. The method for manufacturing a field emission electrode according to claim 7, wherein the tape-like substance containing the carbon nanotubes is synthesized by an arc discharge method, and sandwiched such that a surface on an anode side at the time of the synthesis touches the substrate.

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