JP2005079071A - Electron emitting element and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of an electron emitting element using carbon fibers as an electron emitting member, with high electron emission efficiency, lowered parasitic capacity, less spread of electron beam, capable of impressing a voltage from a gate electrode to respective carbon fibers. <P>SOLUTION: A first electrode 2 is formed on a substrate 1, and an insulation layer 3 is formed so as to cover the first electrode 2. Further, a second electrode 4 having a pair of opposing parts is formed, and carbon fibers 5 of which, one end is connected to the second electrode 4 are arranged along the surface of the insulation layer 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electron-emitting device using a carbon fiber as an electron-emitting member and an image display device using the electron-emitting device.

  In recent years, attention has been paid to a material using a carbon fiber such as a carbon nanotube as an emitter material of a field emission type electron-emitting device. As a method of manufacturing an electron-emitting device using carbon fibers, a method of disposing carbon fibers manufactured in advance in a paste material or the like and disposing them at a predetermined position as disclosed in Patent Document 1 (indirect arrangement method) ), Or after disposing a metal catalyst at a desired position on a substrate as disclosed in Patent Document 2 and the like, carbon fibers are selectively grown in a region where the catalyst is disposed by chemical vapor deposition. And a method (direct arrangement method).

JP 2001-43792 A JP 2000-57934 A

  In order to manufacture an image display device using a field emission type electron-emitting device, in addition to high brightness like a CRT, a driving voltage is reduced to reduce power consumption, and an anode electrode among electrons emitted from the electron-emitting device. It is required to increase the proportion of electrons that reach. In addition, when displaying a moving image on an image display device, there is a demand for reducing the parasitic capacitance of the electron-emitting device itself as much as possible. Furthermore, it is necessary that the electron beam from the electron-emitting device that determines the definition of the image does not spread.

  In an electron-emitting device having a carbon fiber as an electron-emitting member and a gate electrode for applying an electric field for emitting electrons from the carbon fiber, how effective the voltage from the gate electrode ( Whether or not an electric field can be applied is an element that determines the “driving voltage”. The voltage (driving voltage) required for electron emission can be lowered by effectively applying the voltage from the gate electrode. In addition, in the case of an electron emission device in which an anode electrode is disposed so as to face the electron emission element, when the voltage is effectively applied to the carbon fiber, the rate at which the electrons emitted from the carbon fiber reach the gate electrode as much as possible. It is necessary to reduce and increase the amount of electrons that reach the anode electrode to make an efficient electrode arrangement (the efficiency here refers to the electrons that reach the anode among the electrons emitted from the fiber that is the electron emission member) The amount divided by the total amount of electrons emitted from the fiber).

  In addition to the above conditions, in the electron-emitting device, it is necessary to make the capacitance C parasitic on the device as small as possible. The parasitic capacitance of the electron-emitting device leads to a decrease in the ON / OFF responsiveness of the electron emission by discharging the accumulated charge when the applied voltage is switched, and an electron-emitting device having a large parasitic capacitance is applied to an image display device or the like. If it is used, the image quality is degraded.

  For example, the parasitic capacitance C in an electron-emitting device having a cathode electrode and a gate electrode includes the area S of the overlapping portion of the cathode electrode (including the electron-emitting portion) and the gate electrode, the cathode electrode (including the electron-emitting portion), and the gate. Using the distance d between electrodes and the dielectric constant ε of the dielectric that electrically divides the cathode electrode (including the electron emission portion) and the gate electrode, C = ε · s / d.

As means for reducing the electric capacity C,
(A) reducing the area s of the overlapping portion of the cathode electrode (including the electron emission portion) and the gate electrode;
(B) reducing the distance d between the cathode electrode (including the electron emission portion) and the gate electrode;
(C) reducing the dielectric constant ε of the dielectric;
The method is mentioned.

  However, in the case of (b), if d is increased, the electric field applied to the electron emission portion is weakened when the same voltage is applied, and the drive voltage of the electron emission element is increased. Therefore, it is desirable to reduce the area s of the overlapping portion of the cathode electrode (including the electron emission portion) and the gate electrode in (a) as an effective method for avoiding an increase in driving voltage and reducing the parasitic capacitance C.

  In addition to the above-described conditions, when the electron-emitting device is further used in an image display device or the like, the pixel size is determined by the spread of the emitted electron beam. As a matter of course, there is a problem in that the definition of an image formed is limited when the pixel becomes large.

  However, in order to effectively apply a gate voltage to each carbon fiber or to generate a strong electric field between the electron emission portion and the gate electrode due to a decrease in driving voltage, the distance d between the electron emission portion and the gate electrode is reduced. As a result, the amount of electrons incident on the gate electrode increases, and the efficiency of the electron-emitting device tends to decrease. Further, with such a configuration, parasitic capacitance is likely to be generated between the gate electrode and the cathode electrode (including the electron emission portion). In addition, the electron beam extracted by the gate electrode is spread by a potential distribution formed between the gate electrode and the cathode electrode.

  The present invention provides an electron-emitting device having a configuration in which a voltage from a gate electrode can be effectively applied to each carbon fiber, and the efficiency is high, the parasitic capacitance is reduced as much as possible, and the spread of the electron beam is small. It is for the purpose.

The first of the present invention is a first electrode disposed on the substrate surface;
An insulating layer disposed over the first electrode;
A second electrode disposed on the insulating layer, wherein at least a portion of the first electrode does not overlap;
At least one carbon fiber having one end connected to the second electrode and disposed on the first electrode along the surface of the insulating layer;
It is an electron emission element characterized by having.

In the said invention, the following structure is included as a preferable form.
The second electrode has at least a pair of opposing portions.
The thickness of the insulating layer in the region where the second electrode is disposed is thicker than the thickness of the insulating layer in the region other than the region, and the side surface of the thick insulating layer from the second electrode and on the first electrode It has at least one carbon fiber arranged along the surface of the insulating layer.
The first electrode and the second electrode do not overlap with each other through the insulating layer.
A potential higher than the potential applied to the second electrode is applied to the first electrode.
The diameter of the carbon fiber is 1 μm or less.
The carbon fiber is a graphite nanofiber or a carbon nanotube.

  A second aspect of the present invention is characterized by comprising a plurality of the electron-emitting devices according to the first aspect of the present invention, an anode electrode spaced apart from the device, and a light emitting member that emits light by electron irradiation. This is an image display device.

  According to the electron-emitting device of the present invention, a voltage from the gate electrode (first electrode) can be effectively applied to each carbon fiber, the efficiency is low at a low driving voltage, and the parasitic capacitance is reduced as much as possible. Furthermore, the performance that the spread of the electron beam is small is realized. Further, since the image display device of the present invention is configured using the electron-emitting device of the present invention, a higher performance image display device such as a color flat television is realized.

  Embodiments of an electron-emitting device and an image display device according to the present invention are illustratively described below with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the following embodiments are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

  The electron-emitting device of the present invention will be described with reference to FIG. FIG. 1 is a view showing a preferred first embodiment of the electron-emitting device of the present invention, FIG. 1 (a) is a plan view, and FIG. 1 (b) is a cross-sectional view taken along line AA ′ of FIG. In the figure, 1 is a substrate, 2 is a first electrode, 3 is an insulating layer, 4 is a second electrode, and 5 is a carbon fiber.

  As shown in FIG. 1, the electron-emitting device of the present invention is characterized by a first electrode 2 disposed on the surface of a substrate 1, an insulating layer 3 disposed so as to cover the first electrode 2, and the insulation. A second electrode 4 disposed on the layer 3 and not overlapping at least part of the first electrode 2 via the insulating layer 3; one end connected to the second electrode 4; And at least one carbon fiber 5 disposed on the first electrode 2 along the first electrode 2. In the present invention, “along the insulating layer 3 surface” is not necessarily limited to the longitudinal direction of the carbon fiber being parallel to the insulating layer surface. The term “along the surface of the insulating layer 3” in the present invention includes, for example, a form in which carbon fibers are arranged at an inclination of 0 degree or more and less than 90 degrees with respect to the surface of the insulating layer 3. For this reason, in the present invention, at least one end of the carbon fiber 5 is connected to the second electrode 4, and a part of the surface of the insulating layer 3 exists immediately below at least a part of the carbon fiber. (The second electrode 4 does not exist immediately below at least a portion of the carbon fiber), and the insulating layer 3 positioned immediately below at least a portion of the carbon fiber is further below the first layer. A configuration in which at least a part of the electrode 2 exists is an essential configuration.

  In the embodiment of FIG. 1, the second electrode 4 has a pair of opposing parts, and the end of the carbon fiber 5 is connected to each part. Further, the first electrode 2 and the second electrode 4 do not overlap with each other through the insulating layer 3. In the present invention, as shown in FIG. 1, the first electrode 2 and the second electrode 4 do not overlap with each other, so that an effect of reducing parasitic capacitance can be obtained. Further, it is preferable that the second electrode 4 has at least a pair of opposed portions because a convergence effect of the emitted electron beam is obtained.

  In FIG. 1, the end of the carbon fiber 5 is shown connected to the second electrode 4. However, the present invention is not limited to this, and one end of the carbon fiber 5 is connected to the second electrode 4. If it is connected to the two electrodes 4, it can contribute to electron emission.

In the above configuration, when a positive voltage V is applied to the first electrode 2 with respect to the second electrode 4, the shape is determined by the distance between the carbon fiber 5 and the first electrode 2 and the shape of the carbon fiber 5. An electric field depending on the factor is applied to the carbon fiber 5. Here, when the distance between the carbon fiber 5 and the first electrode 2 is reduced, the electric field intensity required to cause the carbon fiber 5 to emit electrons at a relatively low voltage V is 10 ⁶ to 10. ^It can be about ⁷ V / cm. The voltage V for obtaining the electric field intensity necessary for electron emission is the driving voltage of the electron-emitting device.

  In the present invention, the voltage V (driving voltage) can be lowered because the distance between the carbon fiber 5 and the first electrode 2 can be controlled by the film thickness d of the insulating layer 3. The submicron order is possible, and since only the insulating layer 3 exists between the carbon fiber 5 and the first electrode 2, the voltage V is applied directly to the carbon fiber 5 from a short distance. It is because it can do. In FIG. 1, the surface of the insulating layer 3 is shown to be flat, but the thickness of the insulating layer 3 on the first electrode 2 and the thickness d of the insulating layer 3 that does not overlap the first electrode 2 are It can be regarded as substantially the same.

  Since the emitted electrons are present in the insulating layer 3, there is no trajectory for entering the first electrode 2, and the anodes (not shown) arranged above the electron-emitting devices are separated. Therefore, good electron emission efficiency can be obtained. Based on such a principle, the electron-emitting device of the present invention can realize low-voltage driving and obtain good electron emission efficiency.

  Next, as a feature of the electron-emitting device of the present invention, the effect of reducing the electric capacitance C of the electron-emitting portion (in the present invention, the portion where the carbon fiber 5 and the first electrode 2 are closest) will be described.

  As described above, the electric capacity is generally represented by C = ε · s / d. [Where s is the area of the overlapping portion of the cathode electrode and the gate electrode. d: Distance between the cathode electrode and the gate electrode. In the present invention, the cathode electrode corresponds to the carbon fiber 5 and the gate electrode corresponds to the first electrode 2].

  Considering the condition that it is effective to reduce d in order to reduce the driving voltage as an electron-emitting device, it is important how the value of s can be reduced. In the present invention, since there is no film-like cathode electrode in the electron emission portion, the overlapping portion with the first electrode 2 is only the area of 5 of the carbon fiber, and the electric capacity C is reduced while d is in proximity. I can do it.

  Furthermore, the electron-emitting device of the present invention has a configuration in which the electron beam does not spread. The principle is that by arranging a large number of carbon fibers 5 adjacent to each other, a substantially parallel potential distribution is formed on the surface of the first electrode 2 and the surface on which the carbon fibers 5 are disposed, thereby suppressing the spread of the electron beam. Is.

  FIG. 2 shows a second embodiment of the electron-emitting device of the present invention. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along the line B-B ′ of FIG. 2A, in which 6 is a protective layer that is also an insulating layer, and 1 to 5 are the same members as in FIG. 1.

  In the electron-emitting device of FIG. 2, the insulating layer covering the first electrode 2 is composed of the insulating layer 3 and the protective layer 6, and the thickness d2 of the insulating layer in the region where the second electrode 4 is disposed is the other region. The insulating layer is thicker than the thickness d1. In FIG. 2, the surface of the protective layer 6 is shown flat, but the thickness of the protective layer 6 on the first electrode 2 is the thickness of the protective layer 6 in a region that does not overlap the first electrode 2. Is considered to be substantially the same as d1. The carbon fiber 5 is connected to the second electrode 4 at one end, arranged along the side surface of the insulating layer 5 and the surface of the protective layer 6, and the other end reaches the first electrode 2 through the protective layer 6. ing.

  In the configuration of FIG. 2, it is closer to an anode electrode (not shown) located above the electron emission portion than an electron emission portion (in the present invention, indicates a portion where the carbon fiber 5 and the first electrode 2 are closest to each other). By disposing the second electrode 4 as a cathode electrode at the position, the potential surface formed by the second electrode 4 and the potential surface formed by the carbon fiber 5 produce a lens effect, and the electron beam can be converged. The degree of convergence of the electron beam can be selected at a position where the surface of the second electrode 4 is formed with respect to the surface on which the carbon fiber 5 is disposed, if necessary.

  In the embodiment of FIG. 2, the first electrode 2 and the second electrode 4 do not overlap with each other through the protective layer 6 and the insulating layer 3, but as shown in FIG. You can also.

  In the embodiment of FIGS. 2 and 3, the second electrode 4 has a pair of opposing portions, but the present invention is not limited to this. In the present invention, it is preferable that the second electrode 4 has at least a pair of opposing portions in this way because a convergence effect of the emitted electron beam is obtained.

  In the electron-emitting device of the present invention, voltage is effectively applied to the side surface of the carbon fiber 5 (surface in the longitudinal direction of the fiber 5), so that graphene is laminated in the longitudinal direction of the fiber called graphite nanofiber. The material is preferred.

  Based on the principle as described above, according to the electron-emitting device of the present invention, a voltage from the gate electrode (first electrode 2) can be effectively applied to each carbon nanofiber, and a low driving voltage and efficiency can be achieved. The parasitic capacitance is reduced as much as possible, and further, the performance that the spread of the electron beam is small is realized.

  Next, a method for manufacturing the electron-emitting device of the present invention will be described. FIG. 4 is a schematic cross-sectional view showing a manufacturing process of the electron-emitting device shown in FIG.

(Process 1)
A first electrode 2 is formed on the substrate 1 (FIG. 4A). The substrate 1 includes quartz glass, glass in which impurities such as Na are reduced and partially substituted with K, etc., a laminated body in which SiO ₂ is laminated on a blue plate glass or a silicon substrate, or an insulating substrate such as ceramics such as alumina. Can be used.

  The first electrode 2 has conductivity, and is formed by a general vacuum film forming technique such as a printing method, a vapor deposition method, or a sputtering method, or a photolithography technique. The material of the first electrode 2 is appropriately selected from, for example, carbon, metal, metal nitride, metal carbide, metal boride, semiconductor, and semiconductor metal compound. The thickness of the electrode 2 is set in the range of several tens of nm to several μm. Preferably, a heat resistant material of carbon, metal, metal nitride, or metal carbide is desirable.

(Process 2)
Subsequently, the insulating layer 3 is formed [FIG. 4B]. The insulating layer 3 is formed by a general vacuum film forming technique such as a printing method, a vapor deposition method, or a sputtering method, or a photolithography technique. The material is appropriately selected from SiO ₂ , a material to which a substance such as boron or phosphorus is added, or an insulator such as alumina. The thickness of the insulating layer 3 is preferably several tens of nm to several tens of μm.

(Process 3)
Next, the second electrode 4 is formed [FIG. 4C]. The second electrode 4 can be made of the same material as the first electrode 2 described above. A preferred thickness is several nm to several μm. The distance W between the opposing portions of the second electrode 2 is preferably several tens of nm to several tens of μm.

(Process 4)
Next, the carbon fiber 5 is disposed [FIG. 4 (d)]. The carbon fiber in the present invention is “a columnar substance mainly composed of carbon” or “a linear substance mainly composed of carbon”. More specifically, they are graphite fiber, amorphous carbon fiber, carbon nanotube and the like. In the present invention, since a voltage is effectively applied to the side surface of the carbon fiber 5, a material having a graphite end lined up on a side wall of a carbon nanotube or called a graphite nanofiber is preferable, and graphite is particularly preferable. Nanofiber.

  As a method of forming the carbon fiber 5 according to the present invention, the carbon fiber 5 is previously used by using the growth of acicular crystals using nucleus growth by CVD using organic gas, the growth of whisker crystals, or the like, or arc discharge. And an indirect arrangement method in which a purified carbon fiber synthesis method such as a catalytic CVD method, which is produced using a general carbon fiber synthesis method, is disposed on the second electrode 4, and a desired one on the second electrode 4. A direct arrangement method is used in which a catalyst that becomes the nucleus of carbon fiber growth is formed at a position, and organic gas is decomposed to grow carbon fiber by catalyst.

  FIG. 5 shows a manufacturing process for forming the carbon fiber of the electron-emitting device shown in FIG. 2 by a direct arrangement method.

(Process 1)
Similar to the process of FIG. 4A, the first electrode 2 is formed on the substrate 1, and the protective layer 6 is formed thereon. The protective layer 6 has a function as an insulating layer and a function as a protective layer at the time of subsequent etching, and a material to which Al ₂ O ₃ , SiO ₂ , boron, phosphorus or the like is added is used. It is preferably used, and the thickness is preferably several nm to several μm.

  Further, the insulating layer 3 is formed on the protective layer 6 in the same manner as in the step of FIG. A preferable thickness of the insulating layer 3 in this embodiment is several tens of nm to several tens of μm.

  In the same manner as in the step of FIG. 4C, the second electrode 4 is laminated [FIG. 5A].

(Process 2)
Next, catalyst fine particles 7 serving as a nucleus for the growth of the carbon fiber 5 are disposed. As the catalyst particles 7, a solution in which a metal material such as Pd is dispersed in an appropriate solvent is applied on the second electrode 4 and dried (FIG. 5B).

(Process 3)
The catalyst particles 7, the second electrode 4, and the insulating layer 3 are partially etched to expose a part of the protective layer 6 on the first electrode 2 (FIG. 5C). In the exposed region, the distance W between the facing portions of the second electrode 4 is preferably several hundred nm to several hundred μm.

(Process 4)
Next, the carbon fiber 5 is grown using the catalyst particles 7 as nuclei. [FIG. 5D] Specifically, the substrate 1 is placed in a chamber sealed from the outside air, and a carbon-containing gas is introduced to carry out the CVD method.

  Further, in the method of manufacturing the electron-emitting device of FIG. 3, the first electrode 2 is widely formed in the step of FIG. 5A, and the first electrode 2 and the second electrode are formed in the step of FIG. 2 is the same as the method of manufacturing the electron-emitting device in FIG.

The electron-emitting device of the present invention thus manufactured is installed in a vacuum device 12 as shown in FIG. FIG. 6 shows an example using the electron-emitting device having the configuration shown in FIG. Next, the vacuum exhaust device 11 is sufficiently evacuated until it reaches about 10 ⁻⁵ Pa, the anode electrode 8 is provided at a height H of several mm from the substrate 1, and a high voltage Va consisting of several kV from a high voltage power source. Apply. The anode electrode 8 is provided with a phosphor 9 coated with a conductive film.

  In the above configuration, the device current (current flowing between the second electrode 4 and the first electrode 2 of the electron-emitting device) If and the electron emission that flows by applying a pulse voltage of about several tens of volts to the drive voltage Vf When current (current flowing between the second electrode 4 and the anode electrode 8 of the electron-emitting device) and Ie are measured, the device current If is smaller than the emission current Ie, and good electron emission efficiency is obtained.

  At this time, the equipotential surface formed by the electron-emitting device of the present invention and the anode electrode 8 is substantially parallel as indicated by the broken line 10 in the figure, and the spread of the electron beam is suppressed. Further, in the embodiment of FIGS. 1 and 2, there is no overlapping portion between the first electrode 2 and the second electrode 4, and only the carbon fibers intersect, and in the embodiment of FIG. Since the overlapping portion of the electrode 2 and the second electrode 4 is only a region where the insulating layer is sufficiently thick in addition to the carbon fiber other than the electron emission portion, the parasitic capacitance is reduced.

  The drive voltage Vf of the electron-emitting device of the present invention is related to the distance between the carbon fiber 5 and the first electrode 2 and the shape of the carbon fiber 5. When the surface state is the same, the smaller the diameter of the carbon fiber 5 is, the more preferable the electric field concentration effect due to the shape effect appears. Further, the driving voltage is reduced as the distance between the carbon fiber 5 and the first electrode 2 is reduced. These values are appropriately selected depending on the balance between durability and element capacity. Therefore, if a plurality of electron-emitting devices manufactured according to the present invention are arranged in the configuration as shown in FIG. 6, an image display device as shown in FIG. 8 can be manufactured.

  Various arrangements of the electron-emitting devices can be employed. As an example, a plurality of electron-emitting devices are arranged in a matrix form in the X direction and the Y direction, and one of the first electrode 2 or the second electrode 4 constituting the plurality of electron-emitting devices arranged in the same row, A so-called matrix that is commonly connected to the X-direction wiring and connects the other of the first electrode 2 or the second electrode 4 constituting the plurality of electron-emitting devices arranged in the same column to the Y-direction wiring. There is an arrangement.

  A matrix-arranged electron source obtained by arranging a plurality of electron-emitting devices of the present invention will be described with reference to FIG. In FIG. 7, 71 is an electron source substrate, 72 is an X direction wiring, and 73 is a Y direction wiring. 74 is an electron-emitting device of the present invention, and 75 is a connection.

M X-directional wires 72 in FIG. 7 Dx _1, Dx _2, consisting of ... Dx _m. The material, film thickness, and width of the wiring are appropriately designed. Y-direction wiring 73 is made of n wirings of _{Dy 1, Dy 2 ... Dy n} , is formed in the same manner as the X-direction wiring 72. An interlayer insulating layer (not shown) is provided between the m X-direction wirings 72 and the n Y-direction wirings 73 to electrically isolate both (m and n are both Positive integer).

The interlayer insulating layer (not shown) is made of SiO ₂ or the like formed using a vacuum deposition method, a printing method, a sputtering method, or the like. For example, it is formed in a desired shape on the entire surface or part of the base 71 on which the X-direction wiring 72 is formed, and in particular, the film thickness and material so as to withstand the potential difference at the intersection of the X-direction wiring 72 and the Y-direction wiring 73. The manufacturing method is appropriately set. The X direction wiring 72 and the Y direction wiring 73 are drawn out as external terminals, respectively.

  The first electrode 2 and the second electrode 4 (both not shown) constituting the electron-emitting device 74 of the present invention are composed of m X-direction wirings 72, n Y-direction wirings 73, conductive metal, and the like. The connection 75 is electrically connected.

  The material constituting the X-direction wiring 72 and the Y-direction wiring 73, the material constituting the connection, and the material constituting the first electrode and the second electrode may be the same as some or all of the constituent elements. Each may be different. When the material constituting the first electrode 2 and the second electrode 4 is the same as the wiring material, the wirings 72 and 73 can also be collectively referred to as the first electrode wiring and the second electrode wiring, respectively. .

  The X direction wiring 72 is connected to a scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices 74 of the present invention arranged in the X direction. On the other hand, the Y-direction wiring 73 is connected to a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 74 of the present invention arranged in the Y direction according to an input signal. The drive voltage applied to each electron-emitting device 74 is supplied as a differential voltage between the scanning signal and the modulation signal applied to the device.

  In the above configuration, individual elements 74 can be selected and driven independently using simple matrix wiring. An image display apparatus configured using such a simple matrix electron source will be described with reference to FIG. FIG. 8 is a schematic view showing an example of the display panel of the image display apparatus of the present invention.

  In FIG. 8, 71 is an electron source substrate having a plurality of electron-emitting devices, 81 is a rear plate to which the electron source substrate 71 is fixed, and 86 is a face having a fluorescent film 84 and a metal back 85 formed on the inner surface of a glass substrate 83. It is a plate. Reference numeral 82 denotes a support frame, and a rear plate 81 and a face plate 86 are connected to the support frame 82 using frit glass or the like. Reference numeral 88 denotes an envelope, which is configured to be sealed by firing for 10 minutes or more in the temperature range of 400 to 500 ° C. in the air or nitrogen.

  The envelope 87 includes the face plate 86, the support frame 82, and the rear plate 81 as described above. Since the rear plate 81 is provided mainly for the purpose of reinforcing the strength of the base body 71, the separate rear plate 81 can be omitted if the base body 71 itself has sufficient strength. That is, the support frame 82 may be sealed directly to the base 71, and the envelope 87 may be configured by the face plate 86, the support frame 82, and the base 71. On the other hand, by installing a support body (not shown) called a spacer between the face plate 76 and the rear plate 71, the envelope 87 having sufficient strength against atmospheric pressure can be configured.

  Next, the envelope (panel) subjected to the sealing step is sealed.

  The sealing step is performed by exhausting through the exhaust pipe (not shown) by the exhaust device while heating the envelope (panel) 87, exhausting the inside of the envelope, and then sealing the exhaust pipe. In order to maintain the pressure after sealing the envelope 87, a getter process may be performed. As the getter, an evaporation type such as Ba or a non-evaporation type can be used. Here, the method of sealing the exhaust pipe after sealing is shown. However, if the sealing step is performed in a vacuum chamber, it is not necessary to separately provide the sealing step after the sealing step.

The image display apparatus using the electron source of matrix arrangement produced by the above process, each electron-emitting device, applying a voltage via vessel terminals Dx ₁ ~Dx _m, the Dy ₁ ~Dy _n Thus, electrons can be emitted from a desired electron-emitting device. Further, a high voltage is applied to the metal back 85 or the transparent electrode (not shown) via the high voltage terminal Hv to accelerate the electron beam. The accelerated electrons collide with the fluorescent film 84, light emission is generated, and an image is formed.

  The image display apparatus according to the present invention can be used as an image display apparatus as an optical printer configured using a photosensitive drum or the like in addition to a display apparatus such as a television broadcast display apparatus, a video conference system, or a computer. it can.

  An electron-emitting device having the configuration shown in FIG. 1 was fabricated according to the process of FIG.

(Process 1)
After sufficiently washing the substrate 1 using a quartz substrate, 5 nm thick Ti, 50 nm thick Pt, and 5 nm Ti were successively formed as the first electrode 2 by photolithography and sputtering. 4 (a)].

(Process 2)
Subsequently, as the insulating layer 3, SiO ₂ having a thickness of 100 nm was laminated by photolithography and sputtering [FIG. 4 (b)].

(Process 3)
Next, an electrode made of TiC having a thickness of 100 nm was formed as the second electrode 4 by photolithography and sputtering [FIG. 4C]. At this time, as shown in FIG. 1, the first electrode 2 and the second electrode 4 are not overlapped. The distance W between the opposing portions of the second electrode was 5 μm.

(Process 4)
Next, as a carbon fiber, a plurality of carbon nanotubes were dispersed in an organic solvent, applied on the second electrode 4 and the exposed insulating layer 3 in Step 3, and dried by heating to 500 ° C. in an N ₂ atmosphere [ FIG. 4 (d)].

The electron-emitting device manufactured in this example is installed in the vacuum device 12 shown in FIG. 6 and sufficiently evacuated by the vacuum exhaust device 11 until it reaches about 10 ⁻⁵ Pa. An anode electrode 8 was provided, and a high voltage Va consisting of 8 kV was applied. The anode electrode 8 is provided with a phosphor 9 covered with a conductive film. A device current If and an electron emission current Ie flowing by applying a pulse voltage of about 40 V as a drive voltage Vf to the device were measured.

  As a result, the device current If was smaller than the emission current Ie, and the electron emission efficiency was good. In addition, at this time, the spread of the electron beam was small, and light emission of the phosphor corresponding thereto was observed. Furthermore, in the electron-emitting device of this example, there was no overlapping portion between the first electrode 2 and the second electrode 4, and only the carbon fibers 5 intersected, and the parasitic capacitance was reduced.

  As Example 2, an electron-emitting device having the configuration shown in FIG. 2 was fabricated according to the steps shown in FIG.

(Process 1)
In the same manner as in Step 1 of Example 1, after forming the first electrode 2 made of Ti with a thickness of 5 nm, Pt with a thickness of 50 nm and Ti with a thickness of 5 nm on a quartz substrate, a protective layer for an etching step to be described later 6, 100 nm thick Al ₂ O ₃ , 1 μm thick SiO ₂ as the insulating layer 3, and 100 nm thick TiN as the second electrode 4 were successively stacked by sputtering [FIG. 5A].

(Process 2)
Subsequently, a solution in which Pd was dispersed in an organic solvent as the catalyst fine particle 7 that becomes the nucleus of carbon fiber growth was applied and then dried, and the catalyst fine particle 7 was placed on the second electrode 4 [FIG. 5B]. ].

(Process 3)
By using photolithography and reactive dry etching, the catalyst fine particles 7 are dry-etched with Ar plasma, then the second electrode 4 and the insulating layer 3 are dry-etched with a mixed plasma of CF ₄ and H ₂ , and the protective layer 6 is partially formed. It was exposed [FIG.5 (c)]. The distance W between the opposing portions of the second electrode 4 in the exposed region was 10 μm. Under this condition, the etching of Al ₂ O ₃ in the protective layer 6 can be stopped by the protective layer 6 because the etching does not proceed. At this time, an overlapping portion between the first electrode 2 and the second electrode 4 was prevented from being formed as shown in FIG.

(Process 4)
Next, the substrate 1 was placed in a chamber sealed from the outside air, heated in an ethylene stream, and the carbon fiber 5 was grown with the catalyst fine particles 7 as nuclei by the CVD method. At this time, the carbon fiber 5 grew with the fine particles on the second electrode 4 as nuclei, and grew so as to cover the surface of the protective layer 6 (FIG. 5D).

  The electron-emitting device manufactured in this example was installed in the vacuum apparatus 12 shown in FIG. 6 in the same manner as in Example 1, and If and Ie were measured. As a result, as in Example 1, the device current If was smaller than the emission current Ie, and the electron emission efficiency was good. At this time, the electron beam was converged. In the electron-emitting device of this example, the first electrode 2 and the second electrode 4 were not overlapped, and only the carbon fibers 5 intersected, and the parasitic capacitance was reduced.

  An electron-emitting device having the structure shown in FIG. 3 was produced in the same manner as in Example 2 except that the second electrode 2 was formed on the entire surface of the device.

  When a voltage was applied to the device of this example in a vacuum container similar to that of Example 2, a converged electron beam was obtained by the lens effect similar to that of Example 2.

It is a schematic diagram which shows the structure of the 1st electron emission element of this invention. It is a schematic diagram which shows the structure of the 2nd electron emission element of this invention. It is a schematic diagram which shows the structure of the 3rd electron emission element of this invention. FIG. 3 is a manufacturing process diagram of the electron-emitting device in FIG. 1. FIG. 3 is a manufacturing process diagram of the electron-emitting device in FIG. 2. It is a figure which shows the structural example when operating the electron emission element of this invention. It is a plane schematic diagram of an electron source of a simple matrix circuit configured by using a plurality of electron-emitting devices of the present invention. It is a schematic diagram which shows the structural example of the display panel of the image display apparatus comprised using the electron-emitting element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 1st electrode 3 Insulating layer 4 2nd electrode 5 Carbon fiber 6 Protective layer 7 Catalyst fine particle 8 Anode electrode 9 Phosphor 10 Equipotential surface 11 Vacuum exhaust system 12 Vacuum vessel 71 Electron source substrate 72 X direction wiring 73 Y-direction wiring 74 Electron-emitting device 81 Rear plate 82 Support frame 83 Glass substrate 84 Fluorescent film 85 Metal back 86 Face plate 87 Envelope

Claims (8)

A first electrode disposed on the substrate surface;
An insulating layer disposed over the first electrode;
A second electrode disposed on the insulating layer and not overlapping at least a portion of the first electrode;
At least one carbon fiber having one end connected to the second electrode and disposed on the first electrode along the surface of the insulating layer;
An electron-emitting device comprising: The electron-emitting device according to claim 1, wherein the second electrode has at least a pair of opposing portions. The thickness of the insulating layer in the region where the second electrode is disposed is thicker than the thickness of the insulating layer in the region other than the region, and the side surface of the thick insulating layer from the second electrode and on the first electrode The electron-emitting device according to claim 1, further comprising at least one carbon fiber disposed along the surface of the insulating layer. The electron-emitting device according to claim 1, wherein the first electrode and the second electrode do not overlap with each other through an insulating layer. The electron-emitting device according to claim 1, wherein a potential higher than a potential applied to the second electrode is applied to the first electrode. The electron-emitting device according to claim 1, wherein the carbon fiber has a diameter of 1 μm or less. The electron-emitting device according to any one of claims 1 to 6, wherein the carbon fiber is a graphite nanofiber or a carbon nanotube. 8. An image display device comprising: a plurality of electron-emitting devices according to claim 1; an anode electrode spaced apart from the device; and a light-emitting member that emits light by electron irradiation. .

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