JP2006019248A - Electron emitting device, electron source, image display device, and method for manufacturing electron emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent charging of an element portion by using a high resistance film in an electron source using a surface conduction type electron-emitting device, and at the same time, preventing a leakage current generated due to the presence of the high resistance film.
After forming a conductive film 4, a high resistance film 7 is formed in a region excluding the conductive film 4 and its periphery, and a forming process is performed to form a crack 5 in the conductive film 4. By applying a voltage between the device electrodes 2 and 3 in a compound-containing atmosphere, a carbon film 6 is deposited across the high resistance film 7 in the crack 5 and from the end of the crack 5.
[Selection] Figure 1

Description

  The present invention relates to a surface-conduction electron-emitting device in which antistatic measures are taken, an electron source using the same, an image display device using the electron source, and a method for manufacturing the same.

  In recent years, flat panel display devices using surface-conduction electron-emitting devices have been actively developed. The electron-emitting device is formed by forming a pair of device electrodes arranged at a predetermined distance from each other on an insulating substrate usually made of a glass substrate, and a conductive film arranged across the device electrodes. The conductive film is energized to form a crack in the thin film, and electrons are emitted from the crack by applying a voltage between the element electrodes. In an image display device, a plurality of the electron-emitting devices are formed on an insulating substrate, and an electron source substrate formed by matrix wiring and a light-emitting member that emits light by irradiation of electrons emitted from the electron-emitting devices are opposed to each other. Display panel is configured.

In such an electron source substrate, due to the electron emission from the electron-emitting device, the potential on the surface of the insulating substrate becomes unstable, and the startup of the emitted electron beam becomes unstable. In addition, when charged particles such as electrons and ions are injected into the surface of the insulating substrate, secondary electrons are generated, but abnormal discharge occurs particularly under a high electric field. In this case, it has been experimentally confirmed that the device is destroyed. In order to prevent the instability of electron emission characteristics in vacuum and the deterioration of device discharge, it is effective to cover with an appropriate high resistance film so that the insulating surface is not exposed. Therefore, in the conventional electron-emitting device, the insulating surface is covered with a high resistance film having a predetermined sheet resistance to prevent charging. (See Patent Documents 1, 2, and 3)
JP-A-8-180801 JP 11-317149 A Japanese Patent Laid-Open No. 02-060024

  However, when a high-resistance film is formed on the entire substrate surface including the electron-emitting device, a leakage current flows between the device electrodes through the high-resistance film, but the amount of current may be unexpectedly large. As a factor for the flow of a large leak current, the film thickness control of the high resistance film itself is not successful, and the film becomes thicker than desired. If the film thickness of the high-resistance film is large and the sheet resistance decreases, the high-resistance film itself causes a large leakage current at a low voltage when not driven, which places a heavy burden on the driver IC for driving. was there.

  It has also been found that when the high resistance film on the electron-emitting device is too thick, electron emission is inhibited depending on the structure.

  Therefore, when a high resistance film is provided to prevent charging, it is necessary to precisely control the film thickness. However, it has been found that it is difficult to reduce the leakage current only by controlling the film thickness of the high resistance film.

  As a factor, in the current electron-emitting device, in the manufacturing process, a voltage is applied to the conductive film to form a crack to be an electron-emitting portion, and then the voltage is applied to the conductive film in a carbon compound-containing gas atmosphere. The activation process of applying is applied. By this activation process, a carbon deposit mainly composed of carbon and / or carbon compounds is formed in the vicinity of the crack portion to increase the number of emitted electrons, but the above-mentioned conditions are not considered without considering the conditions of the activation process. When the high-resistance film is formed, the deposited carbon is laminated with the high-resistance film at the end of the conductive film. As a result, the sheet resistance is lowered in the vicinity of the emission portion as described above, and the leakage current is increased.

  The flow of these leak currents has caused a problem that the apparent efficiency of the device is lowered. Here, the efficiency of the element refers to a current (hereinafter, referred to as “device current If”) that is discharged in a vacuum relative to a flowing current (hereinafter referred to as “element current If”) when a voltage is applied to a pair of opposing element electrodes of the surface conduction electron-emitting device. The current ratio to the emission current Ie). That is, it is desirable that the element current If is as small as possible and the emission current Ie is as large as possible. However, when the high resistance film is coated as described above, the leakage current due to the high resistance film is added to the element current, so that the efficiency Decreases. If the antistatic film is simply formed away from the conductive film, a part of the insulating substrate is exposed and the exposed part is charged. In particular, charging in the vicinity of the conductive film, particularly in the vicinity of the electron emission portion, has a large influence on the charge emitted from the electron emission portion, and thus easily distorts the electron trajectory of the emitted electrons.

  The present invention can easily form a high-resistance film for stabilizing the electron emission characteristics in the electron-emitting device, the electron source using the electron-emitting device, and the image display device to prevent problems due to charging. At the same time, an object of the present invention is to suppress the weak leakage current at a low voltage when not driven and to reduce the load on the driver IC, thereby enabling the use of an inexpensive driver IC and greatly reducing the panel cost.

  In order to achieve the above object, according to the present invention, a gap is provided between the end of the conductive film of the electron-emitting device and the high-resistance film for preventing charging, and the portion is covered with the electron-emitting device. By connecting with a carbon film, an antistatic effect is obtained, and at the same time, a weak leak current is prevented from flowing.

That is, the first of the present invention is an insulating substrate;
A pair of device electrodes disposed on the insulating substrate;
A conductive film disposed between the pair of element electrodes and partially cracked;
A region extending over the insulating substrate from the intersection of the edge of the conductive film and the crack, and a carbon film located in the crack portion;
An electron-emitting device having a high resistance film that is electrically connected to the pair of device electrodes and covers an insulating substrate except for a region including a predetermined distance from an end of the conductive film,
The carbon film located in a region extending on the insulating substrate from the intersection of the end of the conductive film and the crack is in contact with the high resistance film.

A second aspect of the present invention is a method for manufacturing an electron-emitting device,
Forming a pair of element electrodes and a conductive film between the pair of element electrodes on an insulating substrate;
Forming a water repellent film over the conductive film and over a portion of the conductive film from an end of the conductive film;
Forming a precursor of a high resistance film on the insulating substrate excluding a region where the water repellent film is formed, and on the pair of element electrodes;
Firing the insulating substrate on which the water repellent film and the precursor of the high resistance film are formed, and forming a high resistance film at a distance from the conductive film from the precursor of the high resistance film; ,
Energizing the conductive film through the pair of element electrodes to form a crack in a part of the conductive film;
In a gas atmosphere containing carbon, the conductive film having the crack is energized through the pair of element electrodes, and the high resistance is obtained from the crack portion and the intersection of the end portion of the conductive film and the crack. Forming a carbon film in a region on the insulating substrate extending over the film;
It is characterized by having.

A third aspect of the present invention is a process of forming a pair of element electrodes and a conductive film across the pair of element electrodes on an insulating substrate;
Forming a precursor of a high resistance film on the conductive film and from the end of the conductive film to the insulating substrate;
A water-repellent film is formed on the insulating substrate on which the precursor of the high-resistance film is formed, on the conductive film forming region and a part of the insulating substrate from the end of the conductive film. Process,
Firing the insulating substrate on which the water repellent film and the precursor of the high resistance film are formed, and forming a high resistance film at a distance from the conductive film from the precursor of the high resistance film; ,
Energizing the conductive film through the pair of element electrodes to form a crack in a part of the conductive film;
In a gas atmosphere containing carbon, the conductive film having the crack is energized through the pair of element electrodes, and the high resistance is obtained from the crack portion and the intersection of the end portion of the conductive film and the crack. Forming a carbon film in a region on the insulating substrate extending over the film;
It is characterized by having.

  As described above, in the electron-emitting device of the present invention, since there is no high-resistance film on the conductive film, the conductive film is free from cracks and good electron-emitting characteristics can be obtained. In addition, since the conductive film and the high resistance film are connected by the carbon film, the same good antistatic effect as the conventional one can be obtained, and the element destruction due to the discharge caused by the charging can be prevented. In addition, since there is no high resistance film on the conductive film at the end in the longitudinal direction of the crack, the generation of a leakage current is prevented, and the burden on the drive IC due to the leakage current is reduced.

  In the present invention, it is possible to achieve both prevention of charging and reduction of non-selective current by managing the carbon adhesion amount to an appropriate value.

  Therefore, in the present invention, (1) a leakage current flowing through a non-selected electron-emitting device, (2) unnecessary charging of the electron-emitting device, and (3) defective formation of a crack that is an electron-emitting portion are prevented at the same time. Provided is a highly reliable image display device that does not deteriorate image quality or damage electron-emitting devices even for long-time display.

  Hereinafter, embodiments of the electron-emitting device, the electron source, the image display device, and the manufacturing method thereof according to the present invention will be described.

  FIG. 1 is a schematic view of a preferred embodiment of the electron-emitting device of the present invention, and FIGS. 2 to 6 are schematic views showing the manufacturing process. 1 to 6, (a) is a plan view, and (b) is a cross-sectional view taken along line A-A ′ of (a). In the figure, 1 is an insulating substrate, 2 and 3 are element electrodes, 4 is a conductive film, 5 is a crack formed in the conductive film 4, 6 is a carbon film, 7 is a high resistance film, and 31 is a water repellent film. , 41 is a precursor of a high resistance film. The electron-emitting device and the method for manufacturing the same according to the present invention will be described below by taking the manufacturing process of the electron-emitting device of FIG. 1 as an example.

[Step 1]
The element electrodes 2 and 3 and the conductive film 4 disposed across the element electrodes 2 and 3 are formed on the insulating substrate 1 (FIG. 2).

As the insulating substrate 1, quartz glass, glass with reduced impurity content such as Na, blue plate glass, a laminated body in which SiO ₂ is laminated on the blue plate glass by sputtering or the like, ceramics such as alumina, and a Si substrate are used. be able to.

Moreover, as a material of the device electrodes 2 and 3, a general conductor material can be used. This includes, for example, metals or alloys such as Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, and Pd, and metals or metal oxides such as Pd, Ag, Au, RuO ₂ , and Pd—Ag, and glass. It can be appropriately selected from a printed conductor composed of a transparent conductor such as In ₂ O ₃ —SnO ₂ and a semiconductor material such as polysilicon.

  The element electrode interval L is several tens of nanometers to several hundreds of micrometers, and the photolithography technology that is the basis of the manufacturing method of the element electrodes 2 and 3, that is, the performance of the exposure machine, the etching method, and the like The voltage is set according to the voltage to be applied, but is preferably several μm to several tens of μm.

  The length W2 and the film thickness of the device electrodes 2 and 3 are appropriately designed in consideration of the electrode resistance value, the connection with the wiring, and the problem of the arrangement of the electron source in which a large number of electron-emitting devices are arranged. W2 is several μm to several hundred μm, and the film thickness is several nm to several μm.

  As the conductive film 4, it is preferable to use a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage to the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, forming conditions to be described later, and the like.

  In addition, since the magnitudes of the device current If and the emission current Ie flowing between the device electrodes 2 and 3 depend on the width W1 of the conductive film 4, similarly to the shape of the device electrodes 2 and 3, the electron emitting device. Is designed so that a sufficient emission current can be obtained in a limited size.

  The thermal stability of the conductive film 4 may dominate the lifetime of the electron emission characteristics, and it is desirable to use a material having a higher melting point as the material of the conductive film 4. However, normally, the higher the melting point of the conductive film 4, the more electric power is required for energization forming described later. Further, depending on the form of the electron emission portion obtained as a result, there may be a problem in the electron emission characteristics, such as an increase in applied voltage (threshold voltage) at which electrons can be emitted.

  In the present invention, a material having a high melting point is not particularly required as the material of the conductive film 4, and a material / form that can form a good electron emission portion with a relatively small forming power can be selected.

As an example of a material that satisfies the above conditions, a conductive material such as Ni, Au, PdO, Pd, or Pt is formed with a film thickness in which Rs (sheet resistance) exhibits a resistance value of 1 × 10 ² to 1 × 10 ⁷ Ω / □. What has been used is preferably used. Rs is a value that appears when the resistance R measured in the length direction of a thin film having a thickness of t, a width of w, and a length of l is expressed as R = Rs (l / w). Then, Rs = ρ / t. The film thickness showing the resistance value is in the range of about 5 nm to 50 nm. In this film thickness range, the thin film of each material preferably has the form of a fine particle film.

  The fine particle film described here is a film in which a plurality of fine particles are aggregated, and the fine structure thereof is a state in which the fine particles are individually dispersed and arranged, or a state in which the fine particles are adjacent to each other or overlap each other (some fine particles are aggregated, Including the case where an island-like structure is formed as a whole).

  The particle diameter of the fine particles is in the range of several to hundreds of nm, preferably in the range of 1 nm to 20 nm.

  Furthermore, among the materials exemplified above, PdO can be easily formed into a thin film by firing an organic Pd compound in the air, and since it is a semiconductor, it has a relatively low electrical conductivity and a film thickness for obtaining a resistance value Rs in the above range. This is a suitable material because it has a wide process margin and can be easily reduced to metal Pd after the formation of a crack 5 in the conductive film 4 and the like, so that the film resistance can be reduced. However, the effects of the present invention are not limited to PdO, and are not limited to the materials exemplified above.

  As a specific method for forming the conductive film 4, for example, an organic metal solution is applied between the element electrode 2 and the element electrode 3 provided on the insulating substrate 1 and dried to obtain an organic metal. A film is formed. The organometallic solution is a solution of an organometallic compound whose main element is a metal such as Pd, Ni, Au, or Pt of the conductive film material. Thereafter, the organometallic film is heated and baked and patterned by lift-off, etching, or the like to form the conductive film 4. Further, it can be formed by vacuum deposition, sputtering, CVD, dispersion coating, dipping, spinner, ink jet, or the like.

  1 to 6 show an example in which an organic metal solution is applied onto an insulating substrate 1 by an ink jet method and baked to form a conductive film 4.

[Step 2]
The conductive film 4 and a region including a predetermined distance from the end of the conductive film 4 are covered with a water repellent film 31 (FIG. 3). When the water-repellent film 31 is provided with a high-resistance film material 41 over the entire surface of the insulating substrate 1 (and thus including the device electrodes 2 and 3 and the conductive film 4) in a later step, the high-resistance film material 41 It is a member to remove by repelling. Specifically, a silane coupling material such as dimethyldiacetoxysilane or diethylethoxysilane having water repellency can be used.

  A method for forming the water repellent film 31 is not particularly limited, but an ink jet method can be used as in the case of the conductive film 4. The water repellent film 31 is formed so as to include a region of about 0.5 to 10 μm from the end of the conductive film 4 (W3 = W1 + 1 to 20 μm).

[Step 3]
A high resistance film precursor 41 is applied to the entire surface of the insulating substrate 1. At this time, since the water repellent film 31 is formed in the conductive film 4 and a region including a predetermined distance from the end of the conductive film 4, the precursor of the high resistance film on the water repellent film 31 is formed. 41 is repelled (FIG. 4).

  The material of the high resistance film 7 is preferably a material that can easily obtain a uniform film over a large area. A carbon material, a metal oxide such as tin oxide or chromium oxide, or a conductive material is dispersed in silicon oxide or the like. Are preferred. Further, as a method for applying the precursor 41 of the high resistance film, a spray coating method, a spinner method, a dipping method, or the like is preferably used.

  In the present invention, even if [Step 2] and [Step 3] are interchanged, the embodiment of FIG. 4 can be obtained. That is, after the formation of the conductive film 4, the precursor 41 of the high resistance film is applied to the entire surface of the insulating substrate 1, and then the material solution of the water repellent film 31 is applied on the conductive film 4 by an inkjet method. The material solution is removed so as to push the precursor 41 of the high resistance film on the conductive film 4, so that the material solution of the water repellent film 31 covers the conductive film 4.

[Step 4]
The high resistance film precursor 41 is dried and fired at about 250 ° C. to 400 ° C. to form the high resistance film 7 (FIG. 5). At this time, the water repellent film 31 is burned away by baking, and a region 51 where the high resistance film 7 does not exist is formed in a region where the water repellent film 31 is present. The high resistance film 7 used in the present invention preferably has a sheet resistance of about 1 × 10 ⁸ to 1 × 10 ¹² Ω / □.

[Step 5]
In a reducing atmosphere, an energization process called forming is performed between the device electrodes 2 and 3 to form a crack 5 (FIG. 6). Forming is a process of forming an electron emission portion in an electrically high resistance state by locally destroying, deforming or altering the conductive film 4 by applying a voltage between the device electrodes 2 and 3. is there. At this time, when energized and heated in a reducing atmosphere, for example, in a vacuum atmosphere containing some hydrogen gas, the reduction of the conductive film 4 is promoted by hydrogen. For example, when the conductive film 4 is made of PdO, it changes to a Pd film. When the reduction is changed, a crack 5 is partially formed by the reduction shrinkage of the film.

  In the present invention, since the high resistance film 7 is not in contact with the end portion (outer periphery) of the conductive film 4, the crack 5 due to forming reaches the end portion of the conductive film 4, and the uncut phenomenon occurs. Absent. The uncut phenomenon is a phenomenon that is likely to occur when the high resistance film 7 is laminated on the conductive film 4 like the conventional high resistance film 7 and the high resistance film 7 is in contact with the end of the conductive film 4. In the process of forming the crack 5 while the conductive film 4 is reduced in vacuum by applying voltage and introducing hydrogen, the crack 5 is formed to the end in order to cause a reduction defect at the end of the conductive film 4. A phenomenon that cannot be done. When such an uncut phenomenon occurs, a leak current flows in that portion during driving.

  The electrical processing after the forming process is performed in a suitable vacuum apparatus.

  In the forming process, there are a case where a pulse having a constant pulse peak value is applied and a case where a voltage pulse is applied while increasing the pulse peak value. First, FIG. 7A shows a voltage waveform when a pulse having a constant pulse height is applied.

  In FIG. 7A, T1 and T2 are the pulse width and pulse interval of the voltage waveform, T1 is set to 1 μsec to 10 msec, T2 is set to 10 μsec to 100 msec, and the peak value of the triangular wave (peak voltage at the time of forming) is appropriately selected. .

  Next, FIG. 7B shows a voltage waveform when a voltage pulse is applied while increasing the pulse peak value.

  In FIG. 7B, T1 and T2 are the pulse width and pulse interval of the voltage waveform, T1 is 1 μsec to 10 msec, T2 is 10 μsec to 100 msec, and the peak value of the triangular wave (peak voltage at the time of forming) is 0, for example. Increase by about 1V step.

  The forming process is completed by inserting a voltage that does not cause local destruction or deformation of the conductive film 4 between the forming pulses, for example, a pulse voltage of about 0.1 V, and measuring the element current. For example, when the resistance is 1000 times or more of the resistance before the forming process, the forming is finished.

  When forming the crack 5 described above, a forming process is performed by applying a triangular wave pulse between the device electrodes 2 and 3, but the waveform applied between the device electrodes 2 and 3 is not limited to a triangular wave. A desired waveform such as a rectangular wave may be used, and the resistance value of the electron-emitting device is not limited to the above values for the peak value, the pulse width, the pulse interval, and the like so that the crack 5 can be satisfactorily formed. Select an appropriate value according to the above.

[Step 6]
An activation process is performed on the element that has been formed. The activation treatment is performed by applying a voltage between the device electrodes 2 and 3 under an appropriate vacuum degree in a carbon compound-containing gas atmosphere. By this treatment, the carbon compound existing in the atmosphere is transformed into carbon and carbon. The carbon film 6 mainly composed of a carbon compound is deposited in the crack 5 of the conductive film 4 and at the same time, the carbon film is directed from the intersection of the crack 5 and the end of the conductive film 4 toward the high resistance film 7. 6 is deposited, and the carbon film 6 connects the conductive film 4 and the high resistance film 7.

  Here, the carbon and / or the carbon compound includes, for example, graphite (so-called HOPG, PG, and GC, where HOPG is an almost complete crystal structure of graphite, and PG has a crystal grain of about 20 nm and a crystal structure of somewhat. Disturbed, GC refers to a crystal grain having a crystal structure of about 2 nm and further disordered crystal structure.) And amorphous carbon (amorphous carbon and a mixture of amorphous carbon and graphite microcrystals) ).

Suitable carbon compounds used in the activation step include alkanes, alkenes, alkyne aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxylic acids, sulfonic acids, etc. organic acids can be exemplified, specifically, represented methane, ethane, C _n H _{2n + 2} represented by a saturated hydrocarbon such as propane, ethylene, a composition formula such as propylene C _n H _2n such Unsaturated hydrocarbons, benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine, ethylamine, phenol, benzonitrile, tolunitrile, formic acid, acetic acid, propionic acid, or a mixture thereof can be used.

  The voltage waveform used in this step is shown in FIG. The maximum value of the applied voltage is appropriately selected within a range of 10 to 24V. In FIG. 8A, T1 is the pulse width of the applied voltage, T2 is the pulse interval, and the voltage value is set to have the same positive and negative absolute values. Further, T1 and T1 ′ in FIG. 8B are positive and negative pulse widths of the applied voltage, T2 is a pulse interval, and T1> T1 ′, and the voltage values are set to be equal in absolute value of positive and negative. ing. The deposition state (deposition region, thickness, etc.) of the carbon film is determined by the voltage waveform at the time of activation, adjustment of the application time, and various conditions such as the carbon atmosphere. In the present invention, it is possible to connect the conductive film 4 and the high-resistance film 7 with a carbon film by controlling the activation conditions as desired. Since the discharge amount is set, it is preferable to determine the formation region of the water repellent film 31 so as to correspond to the carbon region formed by activation.

The carbon film 6 obtained in this step has 1 × 10 ⁸ to 1 × 10 ¹² Ω / □ which is substantially the same as the sheet resistance of the high resistance film 7 in terms of sheet resistance. The film thickness of the carbon film 6 that connects the end of the conductive film 4 and the high resistance film 7 is preferably about 2 to 50 nm.

  The electron-emitting device obtained through such processes is preferably subjected to a stabilization process. This step is a step of exhausting the organic substance in the vacuum vessel. As the vacuum exhaust device for exhausting the vacuum vessel, it is preferable to use a device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust apparatus such as a sorption pump or an ion pump can be used.

In the activation step, when an oil diffusion pump is used as an exhaust device and an organic substance gas derived from an oil component to be generated is used, it is necessary to keep the partial pressure of this component as low as possible. The partial pressure of the organic substance component in the vacuum vessel is preferably 1.3 × 10 ⁻⁶ Pa or less, more preferably 1.3 × 10 ⁻⁸ Pa or less in ^{terms of} partial pressure at which the above carbon and carbon compounds are not newly deposited. Is particularly preferred. Furthermore, when evacuating the inside of the vacuum vessel, it is preferable to heat the entire vacuum vessel so that organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device can be easily evacuated. The heating conditions at this time are preferably 80 to 200 ° C. for 5 hours or longer. However, the heating conditions are not particularly limited, and the heating conditions are appropriately selected according to various conditions such as the size and shape of the vacuum vessel and the configuration of the electron-emitting device. . The pressure in the vacuum vessel needs to be as low as possible, preferably 1.3 × 10 ⁻⁵ Pa or less, and more preferably 1.3 × 10 ⁻⁶ Pa or less.

  The driving atmosphere after the stabilization process is preferably maintained at the end of the stabilization process, but is not limited to this, and the degree of vacuum itself is sufficient if the organic material is sufficiently removed. Can maintain sufficiently stable characteristics even if it is somewhat lowered. By adopting such a vacuum atmosphere, deposition of new carbon or a carbon compound can be suppressed, and as a result, the device current If and the emission current Ie are stabilized.

  The basic characteristics of the electron-emitting device of the present invention will be described with reference to FIGS.

  FIG. 11 is a schematic view of a measurement evaluation apparatus for measuring the electron emission characteristics of the electron-emitting device of the present invention. In the figure, 111 is a power source for applying an element voltage Vf to the element, 110 is an ammeter for measuring the element current If flowing through the conductive film 4 including the electron emission portion between the element electrodes 2 and 3, and 114 is An anode electrode for capturing the emission current Ie emitted from the electron emission portion of the device, 113 is a high voltage power source for applying a voltage to the anode electrode 114, and 112 measures the emission current Ie emitted from the crack 5 of the device. This is an ammeter.

  The electron-emitting device and the anode electrode 114 according to the present invention are installed in a vacuum container 115, and the vacuum container is equipped with devices necessary for a vacuum device such as an exhaust pump 116 and a vacuum gauge. The device can be measured and evaluated. Note that the voltage of the anode electrode 114 was 1 kV to 10 kV, and the distance H between the anode electrode 114 and the electron-emitting device was measured in the range of 2 mm to 8 mm.

  FIG. 12 shows a typical example of the relationship between the emission current Ie and device current If measured by the measurement evaluation apparatus shown in FIG. 11 and the device voltage Vf. Although the emission current Ie and the device current If are remarkably different in magnitude, in FIG. 12, the vertical axis is expressed in arbitrary units on a linear scale for qualitative comparison of changes in If and Ie.

  According to the present invention, an electron source can be configured by arranging a plurality of electron-emitting devices on a substrate, and the electron source is combined with a light-emitting member that emits light by electrons emitted from the electron-emitting device. An image display device can be configured.

  FIG. 10 shows a schematic plan view of a preferred embodiment of the electron source of the present invention, in which 91 is an electron source substrate (corresponding to the insulating substrate 1 of FIG. 1), and 92 is a column-direction wiring (Y-direction wiring). , 93 is an interlayer insulating layer, and 94 is a row direction wiring (X direction wiring).

  The manufacturing method of the electron source of the present invention is basically the same as the manufacturing method of the electron-emitting device of the present invention described above. As shown in FIG. 9, the device electrode is formed on the insulating electron source substrate 91. After forming a plurality of electrode pairs of 2 and 3, a column-direction wiring 92 for commonly connecting the element electrodes 3 for each column, and an interlayer insulating layer for electrically insulating the column-direction wiring 92 and the row-direction wiring 94 93, each of the row direction wirings 94 for connecting the element electrodes 2 in common for each row is formed, and then the conductive film 4 is formed on each electrode pair (unit is formed) by the steps of FIGS. A water repellent film 31 is formed to cover the conductive film 4. The column direction wiring 92 and the row direction wiring 94 are formed of a conductive metal or the like having a desired pattern formed by a vacuum deposition method, a printing method, a sputtering method, or the like, and a substantially uniform voltage is supplied to a large number of electron-emitting devices. Thus, the material, film thickness, and wiring width are set.

  5 and 6, the high resistance film precursor 41 is applied onto the substrate 91 and baked. As shown in FIG. 10, the region removed by the water repellent film 31, that is, The high resistance film 7 covers the substrate 91, the device electrodes 2 and 3, and the wirings 92 and 94 except for the conductive film 4 of each unit and the region including a predetermined distance from the end of the conductive film 4.

  FIG. 13 shows a preferred embodiment of the image display device of the present invention using the electron source thus manufactured. FIG. 13 is a perspective view schematically showing the basic configuration by partially cutting away the display panel of the image display apparatus. In FIG. 13, 132 is a rear plate to which the electron source substrate 91 is fixed, 131 is a face plate in which a fluorescent film 137 and a metal back 138 are formed on the inner surface of a glass substrate 136, 133 is a support frame, 134 is a spacer, 139 is An electron-emitting device. For convenience, the high resistance film on the electron source substrate 91 is omitted. In the panel of FIG. 13, the rear plate 132, the support frame 133, and the face plate 131 are sealed by applying frit glass and baking in air or nitrogen at 400 to 500 ° C. for 10 minutes or more. The envelope is configured.

  As described above, the envelope is composed of the face plate 131, the support frame 133, and the rear plate 132. However, since the rear plate 132 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 91, the substrate 91 itself is used. If it has sufficient strength, the separate rear plate 132 is not necessary, and the support frame 133 may be directly sealed on the substrate 91, and the face plate 131, the support frame 133, and the substrate 91 may constitute an envelope. .

  In the panel of FIG. 13, an envelope having sufficient strength against atmospheric pressure is configured by installing a support body called a spacer 134 between the face plate 131 and the rear plate 132.

  In order to further increase the conductivity of the fluorescent film 137, a transparent electrode (not shown) may be provided on the face plate 131 on the outer surface side of the fluorescent film 137.

The envelope is sealed after the degree of vacuum is about 1.3 × 10 ⁻⁵ Pa through an exhaust pipe (not shown). In addition, a getter process may be performed to maintain the degree of vacuum after sealing the envelope. This is because vapor deposition is performed by heating a getter (not shown) disposed at a predetermined position in the envelope by a heating method such as resistance heating or high-frequency heating immediately before or after sealing the envelope. This is a process for forming a film. The getter usually contains Ba or the like as a main component, and maintains a degree of vacuum of, for example, 1.3 × 10 ⁻³ Pa to 1.3 × 10 ⁻⁵ Pa by the adsorption action of the deposited film.

  In the image display device completed as described above, each electron-emitting device 139 emits electrons by applying a voltage from the external terminals Dx1 to Dxm and Dy1 to Dyn to the row direction wiring 94 and the column direction wiring 92, thereby generating high voltage. A voltage of several kV or higher is applied to the metal back 138 or transparent electrode (not shown) through the terminal Hv, the electron beam is accelerated, collides with the fluorescent film 137, and is excited and emitted to display an image. .

  The configuration described above is a schematic configuration necessary for producing a suitable image display device used for display or the like. For example, detailed parts such as materials of each member are not limited to the above-described contents. It selects suitably so that it may suit the use of an image display apparatus.

Example 1
The electron source having the configuration shown in FIG. 10 was produced according to the steps shown in FIGS.

As the electron source substrate 91 used was coated calcining SiO ₂ film 100nm as the sodium blocking layer on a 2.8mm thick glass PD200 alkali components is small (manufactured by Asahi Glass Co.).

  First, a Ti film having a thickness of 5 nm and a Pt film having a thickness of 40 nm are formed on the substrate 91 as a subbing layer by sputtering, and then a photoresist is applied, followed by exposure, development, and etching. To form device electrodes 2 and 3.

  Using an Ag paste (manufactured by Noritake Company), a line-shaped pattern having a thickness of about 10 μm and a line width of 50 μm in contact with the device electrode 3 is printed by a screen printing method, and then baked at 580 ° C. for 8 minutes. Formed.

  Next, an interlayer insulating layer 93 was formed in order to insulate the row direction wiring 94 from the column direction wiring 92. In this example, a paste material containing PbO as a main component and a glass binder is used, and printing is performed by the screen printing method in the same manner as the column-direction wiring 92, and a baking process at 580 ° C. for 8 minutes is ensured for insulation. For this reason, the test was repeated twice. The interlayer insulating layer 93 was formed with a thickness of about 30 μm and a line width of 150 μm. At this time, a contact hole was formed in the insulating layer 93 so that the row direction wiring 94 and the element electrode 2 could be in contact with each other.

  On the insulating layer 93, a line-shaped pattern in contact with the element electrode 2 is printed by screen printing using the same Ag paste as the column-direction wiring, and baked at 480 ° C. for 10 minutes. Formed. The thickness of the wiring was about 15 μm.

  Although not shown, the lead terminal to the external drive circuit was also formed by the same method.

  A conductive film 4 was formed between the device electrodes 2 and 3 by an ink jet coating method. In this step, in order to compensate for the planar variations of the individual device electrodes 2 and 3 on the substrate 91, pattern misalignment is observed at several locations on the substrate 91, and the conductive film material is selected based on the observation results. By applying the solution containing it, the positional deviation of all the pixels was eliminated, and it was applied accurately at the corresponding position.

  In this example, for the purpose of obtaining a Pd film as the conductive film 4, first, 0.15% by mass of Pd-proline complex is dissolved in an aqueous solution composed of 85% by mass of water and 15% by mass of isopropyl alcohol (IPA) to prepare organic palladium. A containing solution was obtained. In addition, some additives were added.

  The droplets of this solution were applied between the device electrodes 2 and 3 by adjusting the amount of the droplets so that the dot diameter was 60 μm using an ink jet ejecting apparatus using a piezoelectric element as a droplet applying unit. Thereafter, the substrate 91 was heated and fired at 350 ° C. for 30 minutes in the air to obtain PdO. The conductive film 4 having a dot diameter (W1 in FIG. 2) of about 60 μm and a maximum thickness of 10 nm after firing was obtained.

  Next, a water repellent film 31 was further formed on the conductive film 4 by an ink jet method. A silane coupling material (DDS) was used as the ink, and was formed to have a diameter of 63 μm so as to spread 1.5 μm from the end of the conductive film 4.

As the high-resistance film precursor 41, a fine particle dispersion solution in which fine particles of tin oxide were dispersed was uniformly applied to the entire surface of the substrate 91 by spray coating. At this time, the precursor 41 of the high resistance film was repelled on the water repellent film 31. The applied high resistance film material 41 was dried and baked at 380 ° C. for 30 minutes to obtain a high resistance film 7. Further, the water repellent film 31 was almost burned out by the heat of baking. The obtained high resistance film 7 had a sheet resistance of 1.2 × 10 ¹⁰ Ω / □.

  In a reducing atmosphere into which some hydrogen was introduced, the forming process was performed with T1 set to 1 msec and T2 set to 80 msec in the voltage waveform of FIG. At the end of the forming process, a voltage at which the conductive film is not locally broken or deformed between the forming pulses, for example, a pulse voltage of about 0.1 V is inserted to measure the element current to obtain the resistance value. The forming was terminated when a resistance of 1000 times or more with respect to the resistance before the forming process was shown.

  In this example, the crack 5 having no uncut phenomenon was formed in the conductive film 4 from end to end by the forming process.

Next, an activation process was performed. Tolunitrile was used as a carbon source and introduced into the vacuum space through a slow leak valve to maintain 1.3 × 10 ⁻⁴ Pa. In this state, in the voltage waveform of FIG. 8 (a), T1 is set to 1 msec, T2 is set to 20 msec, the absolute value of the voltage value is set to 22 V, and a voltage pulse is applied. The carbon film 6 was deposited so as to reach the high resistance film 7 from the intersection of the two. Energization was stopped when the emission current Ie almost reached saturation about 60 minutes after the voltage pulse application, the slow leak valve was closed, and the activation process was completed. The obtained electron-emitting device is shown in FIG.

As a result of analyzing a sample of the obtained carbon film 6, the carbon film 6 between the conductive film 4 and the high resistance film 7 is approximately 1.0 × 10 ¹⁰ Ω / □ which is almost the same as the high resistance film when converted in terms of sheet resistance. It was found to have sheet resistance. The film thickness of the carbon film was about 15 nm.

  The electron emission characteristics of the electron source of this example were evaluated using the measurement evaluation apparatus shown in FIG. The voltage applied between the device electrodes 2 and 3 was measured using 17 V as a standard voltage. At that time, the scanning line voltage on the row direction wiring 94 side was set to -11V, and the signal line voltage on the column direction wiring 92 side was set to + 6V. As a result of measuring Va applied between the anode electrode 114 and the electron source at 1 kV, values of If = 1 mA, Ie = 1.2 μA, and efficiency = 0.12% were obtained. At this time, 6 V is applied as a non-selection voltage to the element not selected. As can be seen from the IV characteristic curve shown in FIG. 12, the element current If flows through the element even when the non-selection voltage is applied, and the non-selection current flows through the drive IC by the number of the non-selected elements. Become.

  In an electron source having a distance between the conductive film 4 and the high resistance film 7 as in this example, even when 6 V is applied to a non-selected electron-emitting device, the leakage current is as low as 0.1 μA or less. The load on the drive driver IC is hardly a problem.

  At the same time, the state of charge in the vicinity of the electron-emitting device was also measured in the form of fluctuations in electron emission efficiency.

(Example 2)
In this embodiment, after the conductive film 4 is formed, a high-resistance film precursor 41 is first applied to the entire surface of the substrate 91, and then the material solution of the water repellent film 31 on the conductive film 4 of each unit. Was prepared in the same manner as in Example 1 except that the high-resistance film precursor 41 on the conductive film 4 was removed by an inkjet method.

  In the obtained electron source, in each electron-emitting device, a carbon film 6 reaching the high resistance film 7 from the intersection of the end of the conductive film 4 and the crack 5 is formed, and the high resistance film 7 and the carbon film 6 The sheet resistance was the same as in Example 1. Further, when the electron emission characteristics of the obtained electron source were evaluated in the same manner as in Example 1, the same result as in Example 1 was obtained.

(Comparative example)
An electron source was produced in the same manner as in Example 1 except that the high resistance film 7 was formed on the entire surface of the substrate 91 by the spray coating method without forming the water repellent film 31. When the electron-emitting device after forming was observed with an SEM (scanning electron microscope), the crack 5 was not formed up to the end of the conductive film 4, and a so-called uncut state was generated. Further, when the activated electron-emitting device was observed with an SEM, a large amount of carbon generated by activation was deposited on the high resistance film 7 at the end of the conductive film 4. The electron emission characteristics of the obtained electron source were evaluated in the same manner as in Example 1. As a result, the leakage current that flowed at the time of non-selection already reached 1 to 2 mA / Line in the initial stage, and further increased with driving, and finally for driving. The capacity of the driver IC is over, and many dark line results are generated when the display panel is constructed.

It is a schematic diagram which shows the structure of preferable embodiment of the electron emission element of this invention. It is a schematic diagram which shows the manufacturing process of the electron emission element of FIG. It is a schematic diagram which shows the manufacturing process of the electron emission element of FIG. It is a schematic diagram which shows the manufacturing process of the electron emission element of FIG. It is a schematic diagram which shows the manufacturing process of the electron emission element of FIG. It is a schematic diagram which shows the manufacturing process of the electron emission element of FIG. It is a figure which shows the forming voltage waveform used for the manufacturing method of the electron-emitting element of this invention. It is a figure which shows the activation voltage waveform used for the manufacturing method of the electron-emitting element of this invention. It is a figure which shows the manufacturing process of preferable embodiment of the electron source of this invention. It is a schematic diagram which shows the structure of preferable embodiment of the electron source of this invention. It is a schematic diagram which shows the structure of the measurement evaluation apparatus of the electron emission characteristic of the electron emission element of this invention. It is a figure which shows the electron emission characteristic of the electron-emitting element of this invention. It is a schematic diagram which shows the structure of the display panel of preferable embodiment of the image display apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating board | substrate 2,3 Element electrode 4 Conductive film 5 Crack 6 Carbon film 7 High resistance film 31 Water repellent film 41 High resistance film material 51 Area | region without a high resistance film material 91 Electron source substrate 92 Column direction wiring 93 Interlayer insulation Layer 94 Row-direction wiring 110, 112 Ammeter 111, 113 Power source 115 Vacuum vessel 116 Exhaust pump 131 Face plate 132 Rear plate 133 Side wall 134 Spacer 136 Glass substrate 137 Fluorescent film 138 Metal back 139 Electron emitting device

Claims (8)

An insulating substrate;
A pair of device electrodes disposed on the insulating substrate;
A conductive film disposed between the pair of element electrodes and partially cracked;
A region extending over the insulating substrate from the intersection of the edge of the conductive film and the crack, and a carbon film located in the crack portion;
An electron-emitting device having a high resistance film that is electrically connected to the pair of device electrodes and covers an insulating substrate except for a region including a predetermined distance from an end of the conductive film,
The electron-emitting device, wherein the carbon film located in a region extending from the intersection of the end portion of the conductive film and the crack to the insulating substrate is in contact with the high resistance film. 2. The electron-emitting device according to claim 1, wherein the high-resistance film has a sheet resistance of 1 × 10 ⁸ to 1 × 10 ¹² Ω / □. The sheet resistance of the carbon film located in a region extending on the insulating substrate from the intersection of the end of the conductive film and the crack is 1 × 10 ⁸ to 1 × 10 ¹² Ω / □. 3. The electron-emitting device according to 2.   4. The electron-emitting device according to claim 1, wherein a thickness of the carbon film located in a region extending on the insulating substrate from an intersection between an end portion of the conductive film and the crack is 50 nm or less. .   An electron source comprising a plurality of electron-emitting devices and wiring connecting the electron-emitting devices on an insulating substrate, the electron-emitting devices according to any one of claims 1 to 4 An electron source characterized by   An image including an electron source including a plurality of electron-emitting devices and wiring connecting the electron-emitting devices on a insulating substrate, and a light-emitting member that emits light by irradiation of electrons emitted from the electron-emitting devices. An image display device, wherein the electron source is the electron source according to claim 5. A method for manufacturing an electron-emitting device, comprising:
Forming a pair of element electrodes and a conductive film between the pair of element electrodes on an insulating substrate;
Forming a water repellent film over the conductive film and over a portion of the conductive film from an end of the conductive film;
Forming a precursor of a high resistance film on the insulating substrate excluding a region where the water repellent film is formed, and on the pair of element electrodes;
Firing the insulating substrate on which the water repellent film and the precursor of the high resistance film are formed, and forming a high resistance film at a distance from the conductive film from the precursor of the high resistance film; ,
Energizing the conductive film through the pair of element electrodes to form a crack in a part of the conductive film;
In a gas atmosphere containing carbon, the conductive film having the crack is energized through the pair of element electrodes, and the high resistance is obtained from the crack portion and the intersection of the end portion of the conductive film and the crack. Forming a carbon film in a region on the insulating substrate extending over the film;
A method for manufacturing an electron-emitting device, comprising: A method for manufacturing an electron-emitting device, comprising:
Forming a pair of element electrodes and a conductive film between the pair of element electrodes on an insulating substrate;
Forming a precursor of a high resistance film on the conductive film and from the end of the conductive film to the insulating substrate;
A water-repellent film is formed on the insulating substrate on which the precursor of the high-resistance film is formed, on the conductive film forming region and a part of the insulating substrate from the end of the conductive film. Process,
Firing the insulating substrate on which the water repellent film and the precursor of the high resistance film are formed, and forming a high resistance film at a distance from the conductive film from the precursor of the high resistance film; ,
Energizing the conductive film through the pair of element electrodes to form a crack in a part of the conductive film;
In a gas atmosphere containing carbon, the conductive film having the crack is energized through the pair of element electrodes, and the high resistance is obtained from the crack portion and the intersection of the end portion of the conductive film and the crack. Forming a carbon film in a region on the insulating substrate extending over the film;
A method for manufacturing an electron-emitting device, comprising:

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