JP3652160B2 - Electron emitting device, electron source, image forming apparatus, and method of manufacturing electron emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron-emitting device, an electron source, an image forming apparatus, and an electron-emitting device manufacturing method.
[0002]
[Prior art]
Conventionally, two types of electron-emitting devices are known: a thermionic source and a cold cathode electron source. Cold cathode electron sources include field emission type (hereinafter abbreviated as FE type), metal / insulating layer / metal type (hereinafter abbreviated as MIM type), surface conduction electron-emitting devices, and the like.
[0003]
As an example of the FE type, W.W. P. Dyke & W. W. Dolan, "Field emission", Advance in Electron Physics, 8, 89 (1956) or C.I. A. Spindt, “Physical Properties of Thin-Film Field Emission Catalysts with Mollybdenium Cones”, J. Am. Appl. Phys. 47, 5248 (1976).
[0004]
Examples of the MIM type include C.I. A. Mead, “Operation of Tunnel-Emission Devices”, J. Am. Apply. Phys. 32,646 (1961) and the like are known.
[0005]
Examples of surface conduction electron-emitting devices include M.I. I. Elinson, RadioEng. Electron Phys. 10, 1290, (1965) and the like.
[0006]
A surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current is applied in parallel to a film surface of a small-area thin film formed on a substrate. As the surface conduction electron-emitting devices, those using the SnO2 thin film by Erinson et al., Those using the Au thin film [G. Ditmmer, Thin Solid Films, 9, 317 (1972)], ln2 O3 / SnO2 thin film [M. Hartwell and C.H. G. Fonsted, IEEE Trans. ED Conf. 519 (1975)], and those using carbon thin films [Hisa Araki et al .: Vacuum, Vol. 26, No. 1, p. 22 (1983)] have been reported.
[0007]
As a typical configuration of these surface-conduction type device emitting devices, the above-described M.P. The element structure of Hartwell is shown in FIG. In the figure, reference numeral 1 denotes an insulating substrate. 4 is a conductive thin film made of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern, and a linear electron emission portion 5 is formed by an energization process called forming described later. In the figure, the element electrode interval L is set to 0.5 to 1 mm, and W is set to 0.1 mm.
[0008]
Conventionally, in these surface conduction electron-emitting devices, it has been common to form the electron-emitting portion 5 in advance by conducting an energization process called forming before conducting the electron emission. In other words, forming means applying and applying a DC voltage or a very slow rising voltage, for example, about 1 V / min, to both ends of the conductive thin film 4 to locally break, deform or alter the conductive thin film, resulting in an electrically high voltage. It is to form the electron emission portion 5 in a resistance state. In the electron emitting portion 5, a crack is generated in a part of the conductive thin film 4, and the electron is emitted from the vicinity of the crack. The surface-conduction type electron-emitting device subjected to the forming process emits electrons from the electron-emitting portion 5 by applying a voltage to the conductive thin film 4 and causing a current to flow through the device.
[0009]
On the other hand, for example, as disclosed in Japanese Patent Application Laid-Open No. 7-235255, a process called activation processing may be performed on an element that has finished forming. The activation treatment process is a process in which the device current If and the emission current Ie are remarkably changed by this process.
[0010]
The activation step can be performed by applying a voltage to the element in the same manner as the forming process in an atmosphere containing an organic substance. By this treatment, carbon or a carbon compound is deposited from an organic substance present in the atmosphere in and near the electron emission portion of the device, and the device current If and the emission current Ie are remarkably changed, so that better electron emission characteristics are obtained. Can be obtained.
[0011]
FIG. 18 shows a cross-sectional shape of an electron-emitting device disclosed in Japanese Patent Laid-Open No. 7-235255. In the figure, reference numerals 1, 4, and 5 are the same as those in FIG. 17, respectively, an insulating substrate, a conductive thin film, and an electron emission portion. 2 and 3 are element electrodes for applying a voltage to the conductive thin film 4, and the voltage is applied with 2 being a low potential side electrode and 3 being a high potential side electrode. By performing the above-described activation process, the electron emission portion 5 shows a structure in which carbon or a carbon compound 6 is deposited, and realizes good electron emission characteristics.
[0012]
An image forming apparatus can be configured by using an electron source substrate on which a plurality of electron-emitting devices as described above are formed and combining with an image forming member made of a phosphor or the like.
[0013]
[Problems to be solved by the invention]
However, due to the rapid development of multimedia with the advancement of information in recent years, higher performance has been demanded for image forming apparatuses such as displays. That is, the display device has a large screen, power saving, high definition, high image quality, and space saving.
[0014]
Therefore, in the above-described electron-emitting device, there is a technology that can maintain a more efficient and stable electron-emitting characteristic for a longer time so that an image forming apparatus to which the electron-emitting device is applied can stably provide a bright display image. It is desired.
[0015]
Here, the efficiency refers to a current (hereinafter referred to as emission) released in a vacuum with respect to a flowing current (hereinafter referred to as element current If) when a voltage is applied between a pair of opposing element electrodes of the surface conduction electron-emitting device. Current ratio) and current Ie).
[0016]
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.
[0017]
If high-efficiency electron emission characteristics can be stably controlled over a long period of time, for example, in an image forming apparatus using a phosphor as an image forming member, a low-power and bright high-quality image forming apparatus such as a flat TV is realized. it can.
[0018]
However, the above-mentioned M.I. Hartwell's electron-emitting devices do not always have satisfactory electron-emitting characteristics and electron-emitting efficiency, and image forming apparatuses with high brightness and excellent operational stability using these elements The reality is that it is extremely difficult to provide.
[0019]
That is, for use in such an application, a sufficient emission current Ie can be obtained with a practical voltage (for example, 10 V to 20 V), the emission current Ie and the device current If do not vary greatly during driving, Although it is necessary that the emission current Ie and the device current If do not deteriorate over time, the conventional surface conduction electron-emitting device has the following problems.
[0020]
As shown in FIG. 17, the surface conduction electron-emitting device has a linear electron-emitting portion 5 that is substantially perpendicular to the voltage application direction.
[0021]
As described above, the electron emission portion 5 is constituted by the gap formed in the conductive thin film by forming. However, when the gap is formed with a uniform width and shape over the entire area as shown in FIG. Is not limited. In the case of such a non-uniform electron emission portion form, there may be a case where a sufficient emission current Ie cannot be obtained, or the characteristic fluctuation or deterioration during driving becomes significant.
[0022]
On the other hand, according to the above-described activation process, a carbon-containing film made of carbon, a carbon compound, or the like is deposited on the substrate in the gap formed in the conductive thin film and on the conductive thin film in the vicinity thereof to form a narrower gap. A part is formed (FIG. 18). The activation process increases the emission current Ie and the device current If. However, the device characteristics such as the electron emission efficiency and the lifetime depend on the shape, structure, and structure of the film having carbon deposited by the activation process or carbon composed of carbon compounds. It depends on stability etc.
[0023]
In particular, since a high electric field is applied to the above-mentioned narrow gap formed in the deposit, the behavior when electrons are emitted between the deposits across this gap and the phenomenon seen as discharge are observed. Suppressing is important for stability. The present invention solves the above-mentioned problems, and its main purpose is to increase the electron emission efficiency of the electron-emitting device and to stabilize the electron emission characteristics.
[0024]
[Means for Solving the Problems]
Therefore, the present inventors have studied in view of the above problems, The following configuration was obtained. A pair of electrodes disposed on the surface of the substrate; and a pair of carbon films separated by a first gap, wherein one of the pair of carbon films is electrically connected to one of the pair of electrodes. And the other of the pair of carbon-containing films is electrically connected to the other of the pair of electrodes, and the conductivity of each of the pair of carbon-containing films is The film having the pair of carbons on the substrate surface in a cross section that is higher from the pair of electrodes toward the first gap portion and is perpendicular to the substrate surface including the first gap portion. An electron-emitting device characterized in that the distance between the pair of carbon-containing films at a position away from the substrate surface is narrower than the distance. A pair of electrodes disposed on the surface of the substrate; and a pair of carbon films separated by a first gap, wherein one of the pair of carbon films is electrically connected to one of the pair of electrodes. And the other of the pair of carbon-containing films is electrically connected to the other of the pair of electrodes, and the conductivity of each of the pair of carbon-containing films is The electron-emitting device, wherein the electron-emitting device has a height from the pair of electrodes toward the first gap, and the substrate surface has a recess in the first gap and carbon in the recess. . Such a configuration Thus, an electron-emitting device having high electron emission efficiency and stable electron emission characteristics for a long time is provided.
[0025]
Further, the present invention is further characterized in that the film having the pair of carbons. Each of Is electrically connected to the electrodes through a conductive thin film disposed between the pair of electrodes Preferred to be The conductive thin film has a second gap between the pair of electrodes. Shi In the second gap Said It is preferred that the first gap is arranged The electron-emitting device is an electron-emitting device that emits electrons by applying a voltage between the pair of electrodes such that the potential of one electrode of the pair of electrodes is higher than the potential of the other electrode. And an extension of a line connecting one end of the pair of carbon-containing films forming the narrowest portion of the first gap and the other end of the pair of carbon-containing films. The thickness of the carbon-containing film connected to the one of the pair of carbon-containing films is 100 nm or less. It is preferable that the carbon in the film having the pair of carbons is graphitic carbon,
It is preferable that the conductive thin film is made of a Pd fine particle film.
[0026]
The present invention is further characterized in that a plurality of the electron-emitting devices described above are formed on a substrate and electrons are emitted from at least one of the electron-emitting devices according to an input signal. The source
The image forming apparatus further includes the electron source and an image forming member that forms an image by irradiating the electrons emitted from the electron source.
[0027]
In addition, in the method for manufacturing an electron-emitting device, a film having carbon from an organic substance present in the atmosphere is applied by applying a voltage between a pair of conductive thin films having a gap in an atmosphere containing the organic substance. In the manufacturing method of the electron-emitting device which is formed around the gap and activates the gap, the activation is performed while heating the gap extremely.
[0028]
It is preferable that the extreme heating of the gap is not performed in the initial stage of forming the carbon-containing film, but is performed from the middle to the later of the formation of the carbon-containing film. Is preferably performed by laser light irradiation.
[0029]
According to the electron-emitting device of the present invention configured as described above, the electric conductivity of the film containing carbon increases toward the first gap portion, so that the potential distribution change in the vicinity of the electron-emitting portion is reduced. For this reason, when the electron-emitting device is driven with the gap as a boundary, it falls into the carbon-containing film or conductive thin film or device electrode to which a higher voltage is applied and is absorbed and part of the device current (If) The amount of electrons that reach the anode electrode (the emission current Ie) increases while the amount of electrons that become the same decreases.
[0030]
Furthermore, when the substrate exposed in the first gap has a recess, the creepage distance between the carbon-containing films facing each other with the gap increases depending on the depth of the recess. As a result, the discharge phenomenon and the device current If which are considered to be caused by a strong electric field applied between the carbon-containing films (gap portions) opposed to each other with the gap portion interposed therebetween are suppressed.
[0031]
Furthermore, although it is estimated that the substrate surface (insulating property) exposed between the gaps is irradiated with emitted electrons, the carbon is formed in the recesses, and this electron is irradiated. As a result, fluctuations and deteriorations in element characteristics that are considered to be caused by the charging phenomenon are suppressed, and the above-described discharge phenomenon is further suppressed.
[0032]
In addition, the manufacturing method of the electron-emitting device makes it possible to obtain an electron-emitting device in which the conductivity of the carbon-containing film increases toward the first gap, and a highly efficient and highly stable electron-emitting device can be obtained. It is done.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
[0034]
First, the basic configuration of the electron-emitting device according to the present invention will be described.
[0035]
FIGS. 1A and 1B are a plan view and a cross-sectional view, respectively, showing the configuration of a basic planar electron-emitting device according to the present invention. 2A, 2B, and 2C are respectively a plan view, a cross-sectional view, and a carbon view schematically showing an enlarged structure in the vicinity of the electron emission portion of the surface conduction electron-emitting device according to the present invention. It is a schematic diagram which shows the electrical conductivity distribution of the film | membrane which has. The basic structure of the element according to the present invention will be described with reference to FIGS.
[0036]
In FIG. 1, 1 is a substrate as a substrate, 2 and 3 are element electrodes as a pair of electrodes, 4 is a conductive thin film, and 5 is an electron emission portion.
[0037]
2A and 2B, 1 is a substrate, 4 is a conductive thin film, 5 is an electron emission portion, and 21 and 22 are substrates in a gap portion (second gap portion) formed in the conductive thin film. 1 is a deposit containing carbon deposited on 1 and the conductive thin film 4 (film: a film having a pair of carbons), and 23 is a substrate altered portion (recess) having carbon atoms. The deposit is opposed to the substrate surface in the lateral direction (parallel to the substrate surface) with the gap 8 (first gap) as a boundary, and is schematically divided into left and right deposits 21 and 22. In some cases, there are some connections. The deposit 21 is also deposited on the conductive thin film 4 on the element electrode 2 side, and the deposit 22 is also deposited on the conductive thin film on the element electrode 3 side.
FIG. 2C schematically shows the conductivity distribution of the carbon-containing film in the direction crossing the gap in FIG. 2A (portion indicated by FF ′). It is mentioned as a feature of the present invention that the height is higher toward the portion 8.
[0038]
With the above configuration, the deposits (21, 22) are electrically connected to the device electrodes (2, 3). In the drawing, the deposits (21, 22), which are films containing carbon, are connected to the device electrodes (2, 3) via conductive thin films. In some cases, they are deposited on the device electrodes (2, 3) and directly connected to each other.
[0039]
Examples of the substrate 1 include a glass substrate obtained by laminating SiO2 formed by sputtering or the like on quartz glass, blue plate glass, blue plate glass or the like, and ceramics such as alumina. These substrates are preferably made of a material containing SiO2, and the electron emission portion 5 having the substrate altered portion 23 more suitable for the present invention can be formed in the activation step described later.
[0040]
Any material may be used as the material of the opposing element electrodes 2 and 3 as long as it has conductivity. For example, Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, Metal or alloy such as Pd, printed conductor composed of metal or metal oxide such as Pd, Ag, Au, RuO2, Pd-Ag and glass, transparent conductor such as ln2 O3-SnO2, and polysilicon And the like, and the like.
[0041]
The element electrode interval L, the element electrode length W, and the shape thereof are appropriately designed according to the application form of the electron-emitting device. For example, in a display device such as a television described later, the pixel size corresponding to the screen size is designed. In particular, a high-definition television requires a small pixel size and high definition. Therefore, in order to obtain a sufficient luminance with the size of the electron-emitting device being limited, the electron-emitting device is designed to obtain a sufficient emission current.
[0042]
The element electrode interval L is several tens of nanometers to several hundred μm, and is set by the photolithography technology that is the basis of the element electrode manufacturing method, that is, the performance of the exposure machine, the etching method, and the voltage applied between the element electrodes. However, it is preferably several μm to several tens μm.
[0043]
The length W of the element electrode and the film thickness d of the element electrodes 2 and 3 are appropriately designed based on the resistance value of the electrode, the connection with the X and Y wirings described above, and the problem of the arrangement of a large number of electron sources. Usually, the length W of the element electrode is several μm to several hundred μm, and the film thickness d of the element electrodes 2 and 3 is several μm from several nm.
[0044]
Not only the configuration shown in FIG. 1 but also a configuration in which the conductive thin film 4 and the opposing element electrodes 2 and 3 are laminated on the substrate 1 in this order may be employed.
[0045]
The conductive thin film 4 is preferably 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 described later, and the like.
[0046]
In addition, since the magnitudes of the device current If and the emission current Ie depend on the width W of the conductive thin film 4, a sufficient emission current can be obtained while the size of the electron-emitting device is limited as in the shape of the device electrode. Designed to be obtained.
[0047]
In general, the thermal stability of the conductive thin 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 thin film 4. However, normally, the higher the melting point of the conductive thin film 4, the more electric power is required for energization forming described later.
[0048]
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.
[0049]
In the present invention, the material of the conductive thin film 4 is not particularly required to have a high melting point, and a material / form that can form a good electron emission portion with a relatively low forming power can be selected.
[0050]
As an example of a material that satisfies the above conditions, a material in which a conductive material such as Ni, Au, PdO, Pd, and Pt is formed with a film thickness that exhibits a resistance value of Rs (sheet resistance) of 102 to 107 Ω / □ 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), and the resistivity is represented by ρ. Then, Rs = ρ / t. The film thickness showing the resistance value is in the range of approximately 5 nm to 50 nm, and in this film thickness range, the thin film of each material has the form of a fine particle film.
[0051]
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).
[0052]
The particle diameter of the fine particles is in the range of several hundred pm to several hundred nm, preferably in the range of 1 nm to 20 nm.
[0053]
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 is a film for obtaining a resistance value Rs in the above range. It is a suitable material because it has a wide thickness process margin and can be easily reduced to metal Pd after forming a gap in the conductive thin film, thereby reducing the film resistance. However, the effects of the present invention are not limited to PdO, and are not limited to the materials exemplified above.
[0054]
The length of the electron emitting portion 5 is substantially determined by the width W ′ of the conductive thin film 4.
[0055]
The electron emission portion 5 is subjected to an activation process described later, so that carbon facing the first gap portion 8 which is narrower than the second gap portion formed in the conductive thin film as shown in FIG. It is comprised by the film | membrane 21 and 22 which have and the board | substrate recessed part 23 which has a carbon atom.
[0056]
The carbon-containing films 21 and 22 are mainly made of graphite-like carbon, but may contain elements constituting the conductive thin film 4.
As shown in FIG. 2, the shapes of the deposits 21 and 22 containing carbon as a main component in the present invention include a height H1 from the surface of each conductive thin film 4 and a high potential to which a higher voltage is applied during driving. It is characterized by the thickness D1 of the side deposit 22 and also by having a narrower portion of the deposit gap 8 above the substrate surface and the conductive thin film surface.
[0057]
Strictly speaking, the height H1 is the conductivity of the portion (point A and point B) where the electric field is strongest when a potential difference is applied between the deposits 21 and 22 so that the deposit 22 has a high potential on the side. It is defined by the height from the surface of the thin film 4, and D1 is defined by the thickness (length) of the deposit existing there when the deposit 22 is cut by an extension line connecting the points A and B. In a broad sense, the position where the electric field is the strongest (point A and point B) is the position where the deposits 21 and 22 are closest (the narrowest gap 8).
[0058]
In order to describe the electron-emitting device of the present invention in detail, first, a measurement evaluation apparatus will be described with reference to FIG.
[0059]
FIG. 3 is a schematic configuration diagram of a measurement evaluation apparatus for measuring the electron emission characteristics of the device having the configuration shown in FIG. In FIG. 3, 1 is a substrate, 2 and 3 are element electrodes, 4 is a conductive thin film, and 5 is an electron emission portion. In addition, 31 is a power source for applying the element voltage Vf to the element, 30 is an ammeter for measuring the element current If flowing through the conductive thin film 4 between the element electrodes 2 and 3, and 34 is from the electron emission portion of the element An anode electrode for capturing the emission current Ie to be emitted, 33 is a high voltage power source for applying a voltage to the anode electrode 34, and 32 is a current for measuring the emission current Ie emitted from the electron emission portion 5 of the device. It is a total.
[0060]
In measuring the device current If and the emission current Ie of the current emitting device, a power source 31 and an ammeter 30 are connected to the device electrodes 2 and 3, and a power source 33 and an ammeter 32 are connected above the electron emitting device. The anode electrode 34 is disposed. The electron-emitting device and the anode electrode 34 are installed in a vacuum device.
[0061]
In FIG. 3, when a voltage is applied between the device electrodes 2 and 3 so that the device electrode 3 is at a high potential, the voltage is applied between the deposit 21 and the deposit 22 shown in FIG. A potential difference is generated according to the applied voltage. At this time, a strong electric field is generated around a point A on the deposit 21 and a point B on the deposit 22. When this electric field is large enough to allow tunneling of electrons from the deposit 21 to the deposit 22, electrons tunnel from the vicinity of the point A on the deposit 21 to the vicinity of the point B on the deposit 22. Conceivable.
[0062]
Here, it is considered that the electrons tunneled from the vicinity of the point A are partially scattered near the point B of the deposit 22 and the remaining portion enters the deposit 22. Here, the electrons partially scattered in the vicinity of the point B of the deposit 22 re-enter the deposit 22 or the conductive thin film 4 and become part of the device current If, and fly in the vacuum. Thus, it is presumed that there are some that are captured by the anode electrode 34 and observed as the emission current Ie. Accordingly, in the electron-emitting device of the present invention, the position where the gap 8 is considered to be the position where the electric field is the strongest is higher than the surface of the conductive thin film 4 connected to the element electrode 3, so that it is scattered. After that, it is considered that the proportion of electrons that enter the conductive thin film 4 and become part of the device current If decreases, and as a result, the proportion of the emission current Ie increases and the electron emission efficiency improves.
The present invention is also characterized in that the conductivity of the film containing carbon is high toward the gap, and therefore the change in potential distribution in the vicinity is small. That is, since the potential rise toward the device electrode 3 is gradual, the force that the scattered electrons receive in the direction of the substrate is reduced. This also causes the device current to enter the conductive thin film 4 after being scattered. It is considered that the proportion of electrons that become a part of If decreases, and as a result, the proportion of the emission current Ie increases and the electron emission efficiency improves.
[0063]
On the other hand, the electrons that have entered the deposit 22 flow to the element electrode 3 through the conductive thin film 4 as they are, and are observed as an element current If by the ammeter 30. In the present invention, the thickness D1 of the deposit 22 is observed. Therefore, it is considered that some of the electrons that have entered through the deposit 22 are emitted into the vacuum through the deposit 22.
[0064]
Therefore, the emission current Ie of the electron-emitting device of the present invention is considered to be composed of an emission current due to electrons scattered by the deposit 22 and an emission current due to electrons transmitted through the deposit 22.
[0065]
The transmittance Te of electrons passing through the deposit 22 can be expressed by the following equation.
[0066]
Te = exp (−D1 / La) (1)
Here, La is the decay length of electrons in the deposit 22.
[0067]
It is known that the decay length in an electron substance (metal) having an energy of 10 eV to 20 eV is approximately 3 to 10 atomic layers. Therefore, for example, when the d002 plane spacing of the carbon constituting the deposit 22 is 0.38 nm and the electron incident direction matches the carbon c-axis, the electron attenuation length is about 1 to 4 nm.
[0068]
For the thickness D1 of the deposit 22 necessary for the transmittance Te of electrons passing through the deposit 22 to be 0.1%, for example, La = 4 nm and Te = 0.001 are substituted into the equation (1). And
D1 = 28nm
It becomes. Usually, the current due to the electrons scattered by the deposit 22 is about 0.1% of the device current If, and therefore the total emission current Ie is considered to be almost doubled by setting the value of D1. .
[0069]
In the present invention, it is more preferable to set the value to be less than or equal to the value of D1. However, it is known that when the density of free electrons in the substance is small (semiconductor or insulator), the electron attenuation length becomes long. The above D1 is not strictly limited to this value because it varies depending on the orientation, interplanar spacing, carrier concentration, etc. of the graphitic carbon constituting the deposit 22, and is preferably 100 nm or less.
[0070]
On the other hand, the electrons that have passed through the deposit 22 re-enter the deposit 22 or the conductive thin film 4 and become part of the device current If, similarly to the scattered electrons, and fly in the vacuum to the anode electrode 34. It is considered that there are some that are captured and observed as emission current Ie.
[0071]
In the present invention, since the shapes of the deposits 21 and 22 that are carbon-containing films are configured as described above, efficient electron emission characteristics can be obtained.
[0072]
Various methods are conceivable as a method for manufacturing the electron-emitting device, and an example is shown in FIG.
[0073]
Hereinafter, the manufacturing method will be described in order based on FIG. 1, FIG. 2, and FIG.
[0074]
1) After the substrate 1 is sufficiently washed with a detergent, pure water and an organic solvent, the device electrode material is deposited by a vacuum vapor deposition method, a sputtering method or the like, and then device electrodes 2 and 3 are formed by a photolithography technique (FIG. 4 ( a)).
[0075]
2) An organometallic film is formed by applying and drying an organometallic solution between the device electrode 2 and the device electrode 3 provided on the substrate 1. The organometallic solution is a solution of an organometallic compound containing a metal such as Pd, Ni, Au, or Pt as a main element. Thereafter, the organometallic film is heated and baked and patterned by lift-off, etching, etc. to form the conductive thin film 4 (FIG. 4B). Here, the application method of the organometallic solution has been described, but the present invention is not limited to this, and it is formed by a vacuum deposition method, a sputtering method, a CVD method, a dispersion coating method, a dipping method, a spinner method, an inkjet method, or the like. In some cases.
[0076]
3) Subsequently, when an energization process called forming is performed by applying a pulsed voltage or a boosted voltage between the device electrodes 2 and 3 with a power source (not shown), a gap 7 is formed in a part of the conductive thin film 4. The conductive thin film is disposed opposite to the substrate surface in the lateral direction across the gap 7 (FIG. 4C). The gap 7 may be connected at a part thereof.
[0077]
The electrical processing after the forming processing is performed in the measurement evaluation apparatus shown in FIG.
[0078]
The measurement evaluation apparatus shown in FIG. 3 is a vacuum apparatus, and the vacuum apparatus includes equipment necessary for a vacuum apparatus such as an exhaust pump and a vacuum gauge (not shown). Can be measured and evaluated. The exhaust pump includes a high vacuum apparatus system such as a magnetic levitation turbo pump and a dry pump that does not use oil, and an ultra high vacuum apparatus system that includes an ion pump. In addition, this measuring apparatus is provided with a gas introducing device (not shown), and vapor of a desired organic substance can be introduced into the vacuum device at a desired pressure. Further, the entire vacuum device and the electron-emitting device can be heated by a heater (not shown).
[0079]
The forming process includes 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. 5A shows a voltage waveform when a pulse having a constant peak value is applied.
[0080]
In FIG. 5A, 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. To do.
[0081]
Next, FIG. 5B shows a voltage waveform when a voltage pulse is applied while increasing the pulse peak value.
[0082]
In FIG. 5B, 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, for example, Increase by about 0.1V step.
[0083]
The forming process is completed by inserting a voltage that does not cause local destruction or deformation of the conductive thin film 4 between the forming pulses, for example, a pulse voltage of about 0.1 V, and measuring the element current to determine the resistance value. For example, when a resistance of 1 MΩ or higher is indicated, the forming is terminated.
[0084]
When forming the gap portion 7 described above, a forming process is performed by applying a triangular wave pulse between the electrodes of the element, but the waveform applied between the electrodes of the element is not limited to a triangular wave, and a rectangular wave A desired waveform may be used, and the peak value, pulse width, pulse interval, and the like are not limited to the above values, and the resistance value of the electron-emitting device is set so that the gap portion 7 is favorably formed. In addition, select an appropriate value.
[0085]
4) Next, an activation process is performed on the element for which forming has been completed. The activation process is performed by introducing a gas of an organic substance into the vacuum apparatus shown in FIG. 3 and applying a voltage between the electrodes of the element in an atmosphere containing the organic substance. Along with the alteration, a film containing carbon is deposited on the element from an organic substance present in the atmosphere, and the element current If and the emission current Ie change remarkably.
[0086]
In the present invention, it is necessary to control the shape of the carbon-containing film deposited by the activation treatment to the shape shown in FIG. 2 with good control. The shape of the carbon-containing film as the deposit depends on the voltage waveform applied to the element, the pressure of the organic substance to be introduced, the diffusion mobility on the element surface, the average residence time on the element surface, and the like. Ease of handling such as ease of introduction into a vacuum apparatus and ease of exhaustion after activation is also important. From the above viewpoint, as a result of examining various organic substances, it was found that a nitrile compound is effective, and particularly when tolunitrile (toluene cyanide) or acrylonitrile is used, it has good controllability. Although the reason why these organic substances are preferably used is not exactly understood, it is considered that the adsorption state on the element surface via the nitrile group (—C≡N) is in conformity with the above conditions. .
[0087]
Below, the formation process of the deposit which is a film | membrane which has carbon in the activation process of this invention is demonstrated using FIG. 6, FIG. In FIG. 6, 1 is a substrate, 2 and 3 are element electrodes, 4 is a conductive thin film, 7 is a second gap formed in the conductive thin film, 21 and 22 are deposits which are films containing carbon, 23 Is a substrate altered portion (concave portion). FIG. 7 shows an example of voltage application to the active device electrode used in the present invention. The maximum voltage value to be applied (constant voltage value in FIG. 7) is appropriately selected within a range of 10 to 20V. In addition, since the discharge may occur when the constant voltage is applied from the beginning of activation, it is preferable to have a process of boosting from a low voltage to a constant voltage as shown in FIG. Furthermore, the initial voltage value of activation is preferably larger than the maximum voltage value applied in the forming.
[0088]
FIG. 6A schematically shows the vicinity of the electron-emitting portion of the electron-emitting device before the activation process. Note that the element is disposed in a vacuum apparatus once depressurized to a pressure of the order of 10 −6 Pa and then introduced with an organic substance gas (FIG. 3). Here, a case where tolunitrile is used as an organic substance will be described as an example. The suitable pressure of tolunitrile to be introduced is slightly affected by the shape of the vacuum apparatus, the members used in the vacuum apparatus, etc., but is about 1 × 10 −5 Pa to 1 × 10 −3 Pa. At a pressure of 1 × 10 −5 Pa or less, the progress of activation is remarkably slow, and the activation may not proceed sufficiently depending on the composition and partial pressure of other remaining gas. On the other hand, at a pressure of 1 × 10 −3 Pa or higher, the progress of activation becomes remarkably fast and it becomes difficult to form the desired deposit shape with good reproducibility. The range of the suitable partial pressure of introduction varies depending on the saturated vapor pressure of the organic substance at that temperature, and in the case of acrylonitrile, it is about 1 × 10 −1 Pa to 1 × 10 −3 Pa.
[0089]
In the activation step (step of depositing a film containing carbon), the voltage shown in FIG. 7 is applied between the device electrodes 2 and 3 (gap portion 7). As a result, the organic substance in the atmosphere begins to deposit on the conductive thin film 4 in and near the gap 7 (FIG. 6B). In this process, the deposits 21 and 22 are simultaneously deposited in the direction perpendicular to the paper surface.
[0090]
Further, when the activation process is continued, the deposition of the deposit increases and grows above the surface of the conductive thin film with the alteration of the substrate (digging described later) (FIG. 6C). Then, the activation process is ended when the final configuration shown in FIG.
[0091]
FIG. 19 shows the state of the current (element current If) flowing between the element electrodes 2 and 3 during the activation process.
[0092]
19A and 19B show the state of deposition of a film containing carbon in the region I in FIG. FIGS. 6C and 6D show the state of deposition of a film containing carbon in the region II.
[0093]
When entering the region II where the device current rises slowly, deposition of the films 21 and 22 having carbon as the deposits progresses upward along with the excavation of the substrate which is the alteration of the substrate. Therefore, when the end of the activation process is determined by measuring the device current, the device current is reduced after the voltage applied to the device electrode at the time of activation enters a constant voltage (const voltage in FIG. 7). After confirming that the region II has been entered, the activation process is terminated.
[0094]
When the voltage shown in FIG. 7 is applied only to the device electrode 3 so that the device electrode 3 becomes positive during the activation process shown in FIG. 6, the carbon-containing film 21, An asymmetric structure in which the height of 22 from the substrate surface is higher in 22 can be formed.
[0095]
In the case of an element having such an asymmetric structure, it is preferable that the potential applied at the time of driving is higher for the electrode electrically connected to the carbon-containing film having a higher height from the substrate surface. By driving in this way, higher electron emission efficiency can be obtained.
[0096]
As shown in FIG. 6D, in order to align the heights of the carbon-containing films 21 and 22 as deposits from the substrate surface, the potential of the waveform shown in FIG. Can be formed by applying a voltage so that the potential of the device electrode 3 becomes negative.
[0097]
In this way, by performing the step of applying a potential whose polarity has been reversed during the activation step, the quality of the carbon constituting the films 21 and 22 having carbon can be made comparable, When the emission element is driven, preferential alteration or disappearance of either one of the films 21 and 22 having carbon exposed to a high temperature can be suppressed, and as a result, the electron emission characteristics can be further stabilized.
[0098]
Further, the alteration (digging) of the substrate is considered as follows.
[0099]
When the temperature rises under the condition that SiO2 (substrate material) is present near carbon, Si is consumed.
[0100]
SiO2 + C → SiO ↑ + CO ↑
When such a reaction occurs, Si in the substrate is consumed, and it is considered that the substrate has a hollow (concave) shape. The electron emission part 5 forms a shape having a carbon deposit protruding upward and the electric field concentrates on the tip part, thereby enabling more stable electron emission.
[0101]
Further, the recess 23 formed in the substrate increases the creeping distance between the deposits 21 and 22 with the first gap portion 8 formed in the deposit as a boundary. By increasing the creepage distance, it is considered that the discharge phenomenon between the deposits 21 and 22 is suppressed even under a high electric field applied between the deposits 21 and 22.
[0102]
In addition, since carbon exists on the surface of the recess, charging of the substrate exposed in the gap 8 is suppressed, and as a result, more stable electron emission characteristics can be obtained.
[0103]
Next, the carbon of the deposits 21 and 22 which is a film having carbon in the present invention will be described.
[0104]
The graphite-like carbon in the present invention is one having a complete graphite crystal structure (so-called HOPG), one having crystal grains of about 20 nm and slightly disturbed crystal structure (PG), crystal grains having a crystal structure of about 2 nm. It includes those with further increased turbulence (GC) and amorphous carbon (which refers to amorphous carbon and a mixture of amorphous carbon and graphite microcrystals). That is, it can be preferably used even if there is a disorder of the layer such as a grain boundary between graphite particles.
[0105]
6) A stabilization process is preferably performed on the electron-emitting device thus manufactured. This step is a step of exhausting the organic substance in the vacuum vessel. Although it is desirable to eliminate the organic substance in the vacuum vessel as much as possible, the partial pressure of the organic substance is preferably 1 to 3 × 10 −8 Pa or less. The pressure including other gases is preferably 1 to 3 × 10 −6 Pa or less, more preferably 1 × 10 −7 Pa or less. A vacuum exhaust device that exhausts the vacuum vessel uses a device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, vacuum exhaust apparatuses such as a sorption pump and an ion pump can be used. Further, when the inside of the vacuum vessel is evacuated, the whole vacuum vessel is heated so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device are easily evacuated. The heating conditions at this time are preferably 150 to 350 ° C., preferably 200 ° C. or higher, for as long as possible. However, the heating conditions are not particularly limited to this, and the size and shape of the vacuum vessel, the arrangement of the electron-emitting devices, etc. It is performed under conditions appropriately selected according to various conditions.
The atmosphere at the time of driving after the stabilization process is preferably maintained at the end of the stabilization process, but is not limited to this, and the pressure itself is sufficient if the organic substance is sufficiently removed. Can maintain sufficiently stable characteristics even if it rises somewhat.
[0106]
By adopting such a vacuum atmosphere, the deposition of new carbon or carbon compounds can be suppressed, so that the shape of the film containing carbon of the present invention is maintained, and as a result, the device current If and the emission current Ie are stabilized.
[0107]
The basic characteristics of an electron-emitting device to which the present invention can be applied manufactured by the manufacturing method as described above will be described with reference to FIGS.
[0108]
FIG. 8 shows typical examples of the emission current Ie, the device current If, and the device voltage Vf of the device after stabilization measured by the measurement evaluation apparatus shown in FIG. In FIG. 8, since the emission current Ie is remarkably smaller than the device current If, it is shown in arbitrary units, and both are linear scales. As is apparent from FIG. 8, the electron-emitting device has three properties with respect to the emission current Ie.
[0109]
First of all, when an element voltage higher than a certain voltage (referred to as threshold voltage, Vth in FIG. 8) is applied to this element, the emission current Ie increases abruptly, while the emission current decreases below the threshold voltage Vth. Ie is hardly detected. That is, it is a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie.
[0110]
Second, since the emission current Ie depends on the element voltage Vf, the emission current Ie can be controlled by the element voltage Vf.
[0111]
Thirdly, the emitted charge trapped by the anode electrode 34 depends on the time during which the device voltage Vf is applied. That is, the amount of charge trapped by the anode electrode 34 can be controlled by the time during which the element voltage Vf is applied.
[0112]
If the characteristics of the electron-emitting device as described above are used, the electron-emitting characteristics can be easily controlled according to the input signal. Furthermore, since the electron-emitting device according to the present invention has stable and high-luminance electron emission characteristics, it can be expected to be applied to various fields.
[0113]
Application examples of the electron-emitting device to which the present invention can be applied will be described below.
[0114]
A plurality of electron-emitting devices according to the present invention can be arranged on a substrate to constitute, for example, an electron source or an image forming apparatus.
[0115]
With respect to the arrangement of elements on the substrate, for example, a large number of electron-emitting devices are arranged in parallel, and a plurality of rows of electron-emitting devices in which both ends of each element are connected by wiring (referred to as a row direction) are arranged. An arrangement form (called a ladder type) in which electrons are controlled and driven by a control electrode (called a grid) installed in a space above the electron source in a direction perpendicular to the wiring (called a column direction), and then On the m X-direction wirings to be described, n Y-direction wirings are installed via an interlayer insulating layer, and the X-direction wirings and the Y-direction wirings are respectively connected to a pair of element electrodes of the surface conduction electron-emitting device. A sequence form is mentioned. This is hereinafter referred to as a simple matrix arrangement.
[0116]
Next, this simple matrix arrangement will be described in detail.
[0117]
According to the characteristics of the above-mentioned three basic characteristics of the surface conduction electron-emitting device according to the present invention, electrons emitted from the surface conduction electron-emitting device are applied between the device electrodes facing each other at a threshold voltage or higher. It can be controlled by the peak value and width of the pulse voltage. On the other hand, it is hardly emitted below the threshold voltage. According to this characteristic, even when a large number of electron-emitting devices are arranged, a surface conduction electron-emitting device can be selected according to an input signal by appropriately applying the pulse voltage to each device, and the electron The amount of release can be controlled.
[0118]
Hereinafter, the configuration of the electron source substrate configured based on this principle will be described with reference to FIG.
[0119]
The m X-directional wirings 102 are made of DX1, DX2,..., DXm, and are formed on the substrate 1 by a vacuum evaporation method, a printing method, a sputtering method, or the like, and made of a conductive metal or the like having a desired pattern. The material, film thickness, wiring width, etc. are designed so that a substantially uniform voltage is supplied to a large number of surface conduction electron-emitting devices. Between these m X-direction wirings 102 and n Y-direction wirings 103, an interlayer insulating layer (not shown) is installed and electrically separated to form a matrix wiring (both m and n are both Positive integer).
[0120]
An interlayer insulating layer (not shown) is SiO2 formed by a vacuum deposition method, a printing method, a sputtering method, etc., and is formed in a desired shape on the entire surface or a part of the substrate 101 on which the X direction wiring 102 is formed. In particular, the film thickness, material, and manufacturing method are appropriately set so as to withstand the potential difference at the intersection of the X-direction wiring 102 and the Y-direction wiring 103. The X-direction wiring 102 and the Y-direction wiring 103 are drawn out as external terminals, respectively.
Further, in the same manner as described above, opposing electrodes (not shown) of the surface conduction electron-emitting device 104 include m X-direction wirings 102 (DX1, DX2,..., DXm) and n Y-direction wirings 103 (DY1). , DY2,..., DYn) and a connection 105 made of a conductive metal or the like.
[0121]
Here, the conductive metals of the element electrodes facing the m X-directional wirings 102, the n Y-directional wirings 103, and the connection 105 are different from each other even if some or all of the constituent elements are the same. May be. These materials are appropriately selected from, for example, the above-described element electrode materials.
[0122]
Although not described in detail later, the X direction wiring 102 is not shown for applying a scanning signal for scanning the row of the surface conduction electron-emitting devices 94 arranged in the X direction according to the input signal. On the other hand, a modulation signal for modulating each column of surface conduction electron-emitting devices 104 arranged in the Y direction according to an input signal is applied to the Y direction wiring 103. Electrically connected to a modulation signal generating means (not shown).
[0123]
Further, the driving voltage applied to each element of the surface conduction electron-emitting device is supplied as a differential voltage between the scanning signal and the modulation signal applied to the element.
[0124]
Next, an example of an electron source using the electron source substrate manufactured as described above and an image forming apparatus used for display or the like will be described with reference to FIGS. FIG. 10 is a basic configuration diagram of the image forming apparatus, and FIG. 11 is a fluorescent film.
[0125]
In FIG. 10, 101 is an electron source substrate on which a plurality of electron-emitting devices are arranged, 111 is a rear plate to which the electron source substrate 101 is fixed, 116 is a face on which a fluorescent film 114 and a metal back 115 are formed on the inner surface of a glass substrate 113. It is a plate. Reference numeral 112 denotes a support frame. The rear plate 111, the support frame 112, and the face plate 116 are coated with frit glass, and sealed in the air or in nitrogen at 400 to 500 ° C. for 10 minutes or more. Thus, the envelope 118 is configured.
[0126]
In FIG. 10, reference numeral 104 corresponds to the surface conduction electron-emitting portion shown in FIG. Reference numerals 102 and 103 denote an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device. In addition, the wiring to these element electrodes may be referred to as element electrodes when the element electrodes and the wiring material are the same.
[0127]
As described above, the envelope 118 is configured by the face plate 116, the support frame 112, and the rear plate 111. However, since the rear plate 111 is provided mainly for the purpose of reinforcing the strength of the substrate 101, the substrate 91 itself is sufficient. When the strength is high, the separate rear plate 111 is not necessary, and the support frame 112 may be directly sealed to the substrate 101, and the envelope 118 may be configured by the face plate 116, the support frame 112, and the substrate 101. .
[0128]
On the other hand, by installing a support body (not shown) called a spacer between the face plate 116 and the rear plate 111, the envelope 118 having sufficient strength against atmospheric pressure can be configured.
[0129]
FIG. 11 shows a fluorescent film. In the case of a monochrome film, the fluorescent film 114 is made of only a fluorescent material. In the case of a color fluorescent film, the fluorescent film 114 is composed of a black conductive material 121 and a fluorescent material 122 called a black stripe or a black matrix depending on the arrangement of the fluorescent materials. . The purpose of providing the black stripe and the black matrix is to make the mixed colors and the like inconspicuous by making the coloration portions between the phosphors 122 of the three primary color phosphors necessary for color display, and in the phosphor film 114 The purpose is to suppress a decrease in contrast due to external light reflection. The material of the black stripe is not limited to the material which is not only a material mainly composed of graphite, which is usually used well, but also a material having conductivity and low light transmission and reflection.
[0130]
As a method of applying the phosphor on the glass substrate 113, a precipitation method, a printing method, or the like is used regardless of monochrome or color.
[0131]
A metal back 115 is usually provided on the inner surface side of the fluorescent film 114. The purpose of the metal back is to improve the brightness by specularly reflecting the light emitted from the phosphor toward the inner surface to the face plate 116 side, to act as an electrode for applying an electron beam acceleration voltage, For example, the phosphor is protected from damage caused by the collision of negative ions generated in the envelope. The metal back can be produced by performing a smoothing process (usually called filming) on the inner surface of the phosphor film after the phosphor film is produced, and then depositing Al using vacuum evaporation or the like.
[0132]
The face plate 116 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 114 in order to further increase the conductivity of the fluorescent film 114.
[0133]
When performing the above-described sealing, in the case of a color, it is necessary to correspond to each color phosphor and the electron-emitting device, so that sufficient alignment is required.
[0134]
The envelope 118 is sealed after the degree of vacuum is about 1 × 10 −7 Torr through an exhaust pipe (not shown). In addition, a getter process may be performed in order to maintain the degree of vacuum after the envelope 118 is sealed. This is because the getter disposed at a predetermined position (not shown) in the envelope 118 is heated by a heating method such as resistance heating or high-frequency heating immediately before or after sealing the envelope 118. This is a process for forming a deposited film. The getter usually contains Ba or the like as a main component, and maintains a vacuum degree of, for example, 1 × 10 −5 or 1 × 10 −7 Torr by the adsorption action of the deposited film.
[0135]
In the image display device of the present invention completed as described above, each electron-emitting device is caused to emit electrons by applying a voltage through the container outer terminals Dox1 to Doxm, Doy1 to Doyn, and through the high voltage terminal 117 to the metal back 115. Alternatively, an image is displayed by applying a high voltage of several kV or more to a transparent electrode (not shown), accelerating the electron beam, colliding with the fluorescent film 114, and exciting and emitting light.
[0136]
The above-described configuration is a schematic configuration necessary for producing a suitable image forming apparatus used for display or the like. For example, detailed portions such as materials of each member are not limited to the above-described contents. It selects suitably so that it may be suitable for the use of an image forming apparatus.
Next, a configuration example of a driver circuit for performing television display based on an NTSC television signal on a display panel configured using an electron source having a simple matrix arrangement will be described with reference to FIG.
[0137]
FIG. 12 is a block diagram showing an example of a driving circuit for performing display in accordance with an NTSC television signal. In FIG. 12, 131 is a display panel, 132 is a scanning signal generation circuit, 133 is a timing control circuit, Reference numeral 134 denotes a shift register. Reference numeral 135 is a line memory, 136 is a synchronizing signal separation circuit, 137 is a modulation signal generating circuit, and Vx and Va are DC voltage sources.
[0138]
The display panel 131 is connected to an external electric circuit via terminals Dox1 to Doxm, terminals Doy1 to Doyn, and a high voltage terminal Hv. For the terminals Dox1 to Doxm, in order to sequentially drive one row (n elements) of an electron source provided in the display panel, that is, a group of surface conduction electron-emitting devices arranged in a matrix of m rows and n columns. The scanning signal is applied. Modulation signals for controlling the output electron beams of the surface conduction electron-emitting devices in one row selected by the scanning signal are applied to the terminals Doy1 to Doyn. The high-voltage terminal Hv is supplied with a DC voltage of, for example, 10 kV from the DC voltage source Va, which gives sufficient energy to excite the phosphor to the electron beam emitted from the surface conduction electron-emitting device. It is an acceleration voltage to do.
[0139]
The scanning signal generation circuit 132 includes m switching elements therein (schematically indicated by S1 to Sm in the drawing). Each switching element selects either the output voltage of the DC voltage source Vx or 0 V (ground level), and is electrically connected to the terminals Dox1 to Doxm of the display panel 131. Each of the switching elements S1 to Sm operates based on a control signal Tscan output from the control circuit 133, and can be configured by combining switching elements such as FETs.
[0140]
In the case of this example, the direct current voltage source Vx has a driving voltage applied to an element not scanned based on the characteristics (electron emission threshold voltage) of the surface conduction electron-emitting element. Is set to output a constant voltage.
[0141]
The timing control circuit 133 has a function of matching the operation of each unit so that appropriate display is performed based on an image signal input from the outside. The timing control circuit 133 generates Tscan, Tsft, and Tmry control signals for each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 136.
[0142]
The synchronization signal separation circuit 136 is a circuit for separating a synchronization signal component and a luminance signal component from an NTSC television signal input from the outside, and can be configured using a general frequency separation (filter) circuit or the like. The synchronization signal separated by the synchronization signal separation circuit 136 includes a vertical synchronization signal and a horizontal synchronization signal, but is illustrated here as a Tsync signal for convenience of explanation. The luminance signal component of the image separated from the television signal is expressed as a DATA signal for convenience. The DATA signal is input to the shift register 134.
[0143]
The shift register 134 is for serial / parallel conversion of the DATA signal input serially in time series for each line of the image, and operates based on the control signal Tsft sent from the timing control circuit 133. (That is, the control signal Tsft can be said to be a shift clock of the shift register 134). Data for one line (corresponding to drive data for N electron-emitting devices) subjected to serial / parallel conversion is output from the shift register 134 as N parallel signals ld1 to ldn.
[0144]
The line memory 135 is a storage device for storing data for one line of an image for a necessary time, and appropriately stores the contents of ld1 to ldn according to a control signal Tmry sent from the timing control circuit 133. The stored contents are output as l′ d1 to l′ dn and input to the modulation signal generator 107.
[0145]
The modulation signal generator 137 is a signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices according to each of the image data l′ d1 to l′ dn, and an output signal thereof is output from the terminals Doy1 to Doy1. The voltage is applied to the surface conduction electron-emitting device in the display panel 131 through Doyn.
[0146]
As described above, the electron-emitting device to which the present invention can be applied has the following basic characteristics with respect to the emission current Ie. That is, there is a clear threshold voltage Vth for electron emission, and electron emission occurs only when a voltage equal to or higher than Vth is applied. For voltages above the electron emission threshold, the emission current also changes with changes in the voltage applied to the device.
[0147]
For this reason, when a pulsed voltage is applied to the device, for example, electron emission does not occur even when a voltage lower than the electron emission threshold is applied, but when a voltage higher than the electron emission threshold is applied, the electron beam is not Is output. At that time, the intensity of the output electron beam can be controlled by changing the pulse peak value Vm. Further, it is possible to control the total amount of charges of the output electron beam by changing the pulse width Pw. Therefore, a voltage modulation method, a pulse width modulation method, or the like can be adopted as a method for modulating the electron-emitting device in accordance with the input signal.
[0148]
When implementing the voltage modulation method, a voltage modulation method circuit is used as the modulation signal generator 137, which generates a voltage pulse of a certain length and appropriately modulates the peak value of the pulse according to the input data. be able to.
[0149]
When implementing the pulse width modulation method, the modulation signal generator 137 generates a voltage pulse having a constant peak value and modulates the width of the voltage pulse as appropriate according to the input data. A circuit can be used.
[0150]
The shift register 134 and the line memory 135 can adopt either a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.
[0151]
When the digital signal system is used, it is necessary to convert the output signal DATA of the synchronization signal separation circuit 136 into a digital signal. For this purpose, an A / D converter may be provided at the output portion of the synchronization signal separation circuit 136. . In this connection, the circuit used in the modulation signal generator 137 is slightly different depending on whether the output signal of the line memory 135 is a digital signal or an analog signal. That is, in the case of a voltage modulation method using a digital signal, for example, a D / A conversion circuit is used as the modulation signal generator 137, and an amplifier circuit or the like is added as necessary. In the case of the pulse width modulation method, the modulation signal generator 137 includes, for example, a high-speed oscillator and a counter that counts the wave number output from the oscillator, and a comparator that compares the output value of the counter with the output value of the memory. A circuit combining (comparators) is used. If necessary, an amplifier for amplifying the pulse width modulated modulation signal output from the comparator to the driving voltage of the surface conduction electron-emitting device can be added.
[0152]
In the case of a voltage modulation method using an analog signal, for example, an amplifier circuit using an operational amplifier or the like can be adopted as the modulation signal generator 137, and a bell shift circuit or the like can be added if necessary. In the case of the pulse width modulation method, for example, a voltage controlled oscillation circuit (VCO) can be adopted, and an amplifier for amplifying the voltage up to the driving voltage of the surface conduction electron-emitting device can be added as necessary.
[0153]
In the image display apparatus to which the present invention that can take such a configuration can be applied, electron emission occurs by applying a voltage to each electron-emitting device via the external terminals Dox1 to Doxm and Doy1 to Doyn. A high voltage is applied to the metal back 115 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 114, light is emitted, and an image is formed.
The configuration of the image forming apparatus described here is an example of an image forming apparatus to which the present invention can be applied, and various modifications can be made based on the technical idea of the present invention. As for the input signal, the NTSC system is mentioned, but the input signal is not limited to this, and other than this, the PAL, SECAM system, and the like, more than this, the TV signal (for example, the MUSE system is used). High-definition TV) can also be adopted.
The image forming apparatus of the present invention can be used as an image forming apparatus as an optical printer configured using a photosensitive drum or the like in addition to a display apparatus for a television broadcast, a video conference system, a computer, or the like. it can.
[0154]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0155]
(Example 1)
The basic configuration of the electron-emitting device according to the present embodiment is a plan view and a sectional view of FIGS. 1A and 1B and an enlarged view of FIGS. 2A, 2B, and 2C. It is the same as the plan view, the cross-sectional view, and the conductivity distribution diagram of the film containing carbon.
[0156]
The manufacturing method of the surface conduction electron-emitting device according to this example is basically the same as that shown in FIGS. Hereinafter, the basic configuration and manufacturing method of the element according to the present embodiment will be described with reference to FIGS. 1, 2, 4, and 6.
[0157]
Hereinafter, the manufacturing method will be described in order based on FIGS. 1, 2, 4, and 6.
[0158]
Step-a
First, on the cleaned quartz substrate 1, a pattern to be the gap L between the device electrodes 2 and 3 and a desired device electrode is formed with a photoresist (RD-2000N-41 manufactured by Hitachi Chemical Co., Ltd.), and an electron beam evaporation method is performed. Then, Ti having a thickness of 5 nm and Pt having a thickness of 30 nm were sequentially deposited. The photoresist pattern was dissolved in an organic solvent, the Pt / Ti deposited film was wrist-off, the device electrode interval L was 3 μm, and the device electrodes 2 and 3 having a device electrode width W of 500 μm were formed (FIG. 4A). .
[0159]
Step-b
A 100 nm thick Cr film is deposited by vacuum deposition and patterned to have an opening corresponding to the shape of the conductive thin film described later, and then an organic palladium compound solution (ccp4230, manufactured by Okuno Pharmaceutical Co., Ltd.) is rotated by a spinner. Application and heat baking treatment at 300 ° C. for 12 minutes were performed. The conductive thin film 4 made of fine particles of Pd as the main element thus formed had a thickness of 10 nm and a sheet resistance Rs of 2 × 10 4 Ω / □. Note that the fine particle film described here is a film in which a plurality of fine particles are aggregated as described above.
[0160]
Step-c
The Cr film and the fired conductive thin film 4 were etched with an acid etchant to form the conductive thin film 4 having a desired pattern so that the width W ′ of the conductive thin film 4 was 300 μm (FIG. 4B). ).
[0161]
Through the above steps, the device electrodes 2 and 3 and the conductive thin film 4 were formed on the substrate 1.
[0162]
Note that the devices of Comparative Examples 1 and 2 were fabricated through the exact same process.
[0163]
Step-d
Next, the device is installed in the measurement / evaluation apparatus shown in FIG. A voltage was applied between the electrodes 2 and 3 to perform a forming process, and the first gap 7 was formed in the conductive thin film. The voltage waveform of the forming process is as shown in FIG. 5B (FIGS. 4C and 6A).
[0164]
In FIG. 5B, T1 and T2 are the pulse width and pulse interval of the voltage waveform. In this embodiment, T1 is 1 msec, T2 is 16.7 msec, and the peak value of the rectangular wave is boosted in 0.1 V steps. Then, a forming process was performed. During the forming process, a resistance measurement pulse was inserted between the forming pulses at a voltage of 0.1 V at the same time to measure the resistance. The forming process was terminated when the measured value with the resistance measurement pulse became about 1 MΩ or more, and at the same time, the voltage application to the element was terminated. The maximum voltage applied by forming was about 5V.
[0165]
Step-e
Subsequently, to perform the activation process, tolunitrile was introduced into the vacuum apparatus through a slow leak valve, and 1.3 × 10 −4 Pa was maintained. Next, an activation voltage waveform as shown in FIG. 7B is repeatedly applied to the element subjected to the forming process via the element electrodes 2 and 3. Specifically, the device electrode 2 is set to 0 V, a positive rectangular wave having a pulse width of T3 = 1 msec is applied to the device electrode 3, and then a negative rectangular wave having the same pulse width is applied, and this is a cycle of T4 = 10 msec. Apply repeatedly at. Further, the absolute value of the peak value of the pulse applied at that time was boosted at a constant rate from 6 V to 15 V as shown in FIG. 7A, and then maintained at 15 V for activation processing. At this time, the voltage applied to the device electrode 3 is positive, and the device current If flows in the direction from the device electrode 3 to 2 in the positive direction. After confirming that it entered the region II in FIG. 19 after about 60 minutes, the energization was stopped, the slow leak valve was closed, and the activation process was completed.
[0166]
On the other hand, the activation process was performed on the elements of Comparative Examples 1 and 2 in which the same forming process as that of the element of this example was performed under the following conditions.
[0167]
Element of Comparative Example 1: Same as the element of this example, except that the partial pressure of tolunitrile was changed to 1.3 × 10 −2 Pa
Element of Comparative Example 2: Same as the element of this Example except that the partial pressure of tolunitrile was 1.3 × 10 −6 Pa
Step-f
Subsequently, a stabilization process is performed. While the vacuum device and the electron-emitting device were heated by a heater and maintained at about 250 ° C., the vacuum device was continuously evacuated. After 20 hours, heating with the heater was stopped and the temperature was returned to room temperature, and the pressure in the vacuum apparatus reached about 1 × 10 −8 Pa.
[0168]
Subsequently, the electron emission characteristics were measured.
[0169]
The distance H between the anode electrode 34 and the electron-emitting device was 4 mm, and a potential of 1 kV was applied to the anode electrode 34 by the high voltage power source 33. In this state, a rectangular pulse voltage having a peak value of 15 V is applied between the device electrodes 2 and 3 using the power supply 31, and the device of the present embodiment and the device of the comparative example are applied by the ammeter 30 and the ammeter 32. The current If and the emission current Ie were measured.
In the device of this example, the device current If was substantially the same as that of Comparative Example 1, but the emission current Ie showed a larger value than that of Comparative Example 1, and an efficient device was obtained. Further, in the device of Comparative Example 2, the device current If was extremely low, and a sufficient emission current Ie could not be obtained.
[0170]
From this result, it was found that the device of this example had a large emission current Ie and an excellent electron emission efficiency η compared to the device of the comparative example.
[0171]
Moreover, the scanning tunneling microscope (STM) observation, atomic force microscope (AFM) observation, and transmission electron microscope (TEM) observation were performed about the element of the present Example produced by the said process, and the element of a comparative example.
[0172]
First, the potential distribution of the carbon-containing film in the vicinity of the electron emission portion was observed using a scanning tunneling microscope while applying a voltage lower than that in the case where electrons were emitted to the device prepared as described above. As a result, the potential of the carbon-containing film increases as the distance from the gap portion increases for any element. However, in the element of this example, the potential increase in the vicinity of the gap portion is small and increases as the distance from the gap portion increases. It turned out that the rate was rising. That is, in the device of this example, as shown in FIG. 2C, the conductivity of the film containing carbon increases toward the gap. Therefore, the potential distribution change in the vicinity of the electron emitting portion, specifically, the potential rise is suppressed, and as a result, the carbon on the side to which a higher voltage is applied when the electron emitting element is driven with the gap as a boundary. The amount of electrons falling to and absorbed by a film, a conductive thin film, or an element electrode and becoming part of the element current (If) decreases while the amount of electrons reaching the anode electrode (emission current Ie) increases. We think that.
[0173]
Next, the shape of the plane including the electron emission portion 5 of the device was observed using an atomic force microscope. The shape of the element of this example was the same as the planar shape shown in FIG. That is, deposits 21 and 22 were observed on both sides of the gap 7 formed in the conductive thin film 4. Further, from the height information obtained from the atomic force microscope, the height of the highest portion of the deposit is about 80 nm higher than the surface of the conductive thin film 4, and the deposit at that height has a width of 500 nm. It had a belt-like shape. On the other hand, in the element of Comparative Example 1, deposits were observed on both sides of the gap formed in the conductive thin film 4 as in the element of this example, but the height of the deposits was almost uniform. The band-like shape as in the device of this example was not observed. Moreover, when the element of Comparative Example 2 was observed, there were scattered places where there was a deposit and places where there was no deposit on both sides of the gap formed in the conductive thin film 4.
[0174]
Next, the transmission electron microscope observation of the cross section including the deposit of each element was performed.
[0175]
As a result, the deposit in the vicinity of the gap 8 of the element of the present example has the same shape as shown in FIG. 2B, and the height of the portion corresponding to the deposits 21 and 22 is about 80 nm. It was. The deposit 21 is connected to the element electrode 2 of FIG. 1 via the conductive thin film 4, and the deposit 22 is connected to the element electrode 3 of FIG. 1 via the conductive thin film 4. A film containing carbon was also deposited on the conductive film 4 and its height was about 20 nm. Furthermore, when the thickness of the part corresponding to thickness D1 was measured, it was about 25 nm.
[0176]
The depth of the substrate altered portion (recessed portion) was about 30 nm, and the presence of carbon atoms was also confirmed in the altered portion. A cavity was observed in the center.
[0177]
On the other hand, the deposit of the element of Comparative Example 1 was thickly covered with the entire gap formed in the conductive thin film, and the shape as shown in FIG. 2B was not observed.
[0178]
Furthermore, in the element of Comparative Example 2, the amount of deposits was small, so the detailed shape was not known.
[0179]
Finally, the deposit in the vicinity of the gap formed in the conductive thin film of the device of this example was subjected to elemental analysis by electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS), and further Auger electron spectroscopy, It was confirmed that the deposit was mainly composed of carbon.
[0180]
From these observation results, in the element of this example, the deposited deposits 21 and 22 are films having carbon whose main component is graphite-like carbon, and carbon is also present in the substrate altered portion 23, and the central portion. Since there is a cavity and has the same shape as that shown in FIG. 2B, good emission of electrons with high emission current Ie and high emission efficiency η was obtained. In addition, when the devices of Example 1 and Comparative Examples 1 and 2 were driven for the same time, the device of the comparative example showed earlier deterioration in electron emission characteristics than the device of this example, and some of the devices of the comparative example However, the device characteristics of this example were little deteriorated and stable characteristics were obtained.
[0181]
(Example 2)
In this example, the same processes as those in Example 1 were performed up to process-d. As the substrate 1, a Corning 7059 substrate was used.
[0182]
Step-e
Subsequently, in order to perform the activation process, benzonitrile was introduced into the vacuum apparatus through a slow leak bubble, and 1.3 × 10 −4 Pa was maintained. Next, the voltage was applied to the element subjected to the forming process from 6V to 15V with the waveforms shown in FIGS. 7A and 7B in the same manner as in Example 1, and the absolute value of the peak value became 15V. It was maintained and activated. At this time, the activation process was performed while irradiating the laser beam in the vicinity with the gap portion as the center, the voltage applied to the device electrode 3 was positive, and 0 V was applied to the device electrode 2. The element current If flows in the direction from the element electrode 3 to 2 in a positive direction. After about 50 minutes, it was confirmed that the applied voltage was a constant potential of 15 V and the device current entered the region II shown in FIG. 19, and then the energization was stopped, the slow leak valve was closed, and the activation process was completed. .
[0183]
On the other hand, the activation process was performed on the elements of Comparative Examples 3 and 4 in which the same forming process as that of the element of this example was performed under the following conditions.
[0184]
Device of Comparative Example 3: Same as the device of the present example except that the partial pressure of introduction of benzonitrile was 1.3 × 10 −2 Pa
Device of Comparative Example 4: Same as the device of this example except that the partial pressure of benzonitrile introduced was 1.3 × 10 −6 Pa
Step-f
Subsequently, a stabilization process is performed. While the vacuum device and the electron-emitting device were heated by a heater and maintained at about 250 ° C., the vacuum device was continuously evacuated. After 20 hours, heating with the heater was stopped and the temperature was returned to room temperature, and the pressure in the vacuum apparatus reached about 1 × 10 −8 Pa.
[0185]
Subsequently, the electron emission characteristics were measured.
[0186]
A distance H was set to 4 mm between the anode electrode 34 and the electron-emitting device, and a potential of 1 kV was applied to the anode electrode 34 by the high voltage power source 33. In this state, a rectangular pulse voltage having a peak value of 15 V is applied between the device electrodes 2 and 3 using the power source 31 with the device electrode 2 being 0 V and the device electrode 3 being 15 V, and the ammeter 30 and the ammeter 32 are used. The device current If and the emission current Ie of the device of this example and the device of the comparative example were measured, respectively.
[0187]
In the device of this example, the device current If was substantially the same as that of Comparative Example 1, but the emission current Ie showed a larger value than that of Comparative Example 1, and an efficient device was obtained. Further, in the device of Comparative Example 2, the device current If was extremely low, and a sufficient emission current Ie could not be obtained.
[0188]
From this result, it was found that the device of this example had a large emission current Ie and an excellent electron emission efficiency η compared to the device of the comparative example.
In addition, as in Example 1, the element of this example manufactured in the above process was observed with a scanning microscope (STM), an atomic force microscope (AFM), and a transmission electron microscope (TEM). The conductivity of the carbon-containing film in the vicinity of the electron emission portion in the device of this example is higher toward the gap as shown in FIG. 20B, and the shape of the film is as shown in FIG. The deposits 21 and 22 have the same shape as that shown in FIG. In the device of this example, the height corresponding to the deposits 21 and 22 in FIG. 2B was about 10 nm. Further, the depth of the substrate altered portion was 40 nm, and a cavity was observed at the center. Next, the probe was narrowed down in TEM, and elemental analysis of the substrate altered portion 23 was performed by energy dispersive X-ray spectroscopy (EDS). When compared with the substrate portion (unmodified portion) under the conductive film 4 having the same depth as the substrate modified portion 23, the ratio of Ba and Al in the substrate was not changed. On the other hand, it was found that Si decreased. Further, carbon was detected on the surface of the concave portion, which is a cavity of the altered portion of the substrate.
[0189]
Finally, the deposit in the vicinity of the gap 8 of the element of this example is subjected to elemental analysis by EDS and X-ray photoelectron spectroscopy (XPS), and further Auger electron spectroscopy, and the deposit contains carbon whose main component is carbon. It was confirmed that it was a film having.
[0190]
From these observation results, also in the element of this example, the deposits 21 and 22 are mainly composed of graphite-like carbon, and have the same shape as that shown in FIG. Moreover, it turned out that the board | substrate altered part 23 has a hollow structure containing carbon and consuming Si. From these, good electron emission with high emission efficiency η was obtained. In addition, when the device of this example and the devices of comparative examples 3 and 4 were driven for the same time under the same conditions, the device of the comparative example had a faster characteristic deterioration than that of the device of this example, and was seen as a discharge. Although the phenomenon was observed, the characteristics of the device of this example were very stable.
[0191]
In the step-e, the laser beam irradiation is not performed in the initial stage of the formation of the deposits 21 and 22 but starts after the deposits 21 and 22 grow to a certain size, or in accordance with the growth. By changing the irradiation intensity, it is possible to set the change in conductivity more appropriately.
[0192]
(Example 3)
This embodiment is an example of an image forming apparatus using an electron source in which a large number of surface conduction electron-emitting devices are arranged in a simple matrix.
[0193]
A plan view of a part of the electron source is shown in FIG. FIG. 14 is a cross-sectional view taken along the line AA ′ in the drawing. However, in FIG. 13 and FIG. 14, what showed the same symbol shows the same thing. Here, 101 is a substrate, 102 is an X direction wiring (also referred to as a lower wiring) corresponding to DXm in FIG. 9, 103 is a Y direction wiring (also referred to as an upper wiring) corresponding to DYn in FIG. 9, 4 is a conductive thin film, 2, 3 are element electrodes, 171 is an interlayer insulating layer, and 172 is a contact hole for electrical connection between the element electrode 2 and the lower wiring 102.
[0194]
Next, the manufacturing method will be specifically described according to the order of steps with reference to FIGS.
[0195]
Step-a
After sequentially depositing 5 nm thick Cr and 0.6 mm thick Au on the substrate 1 on which a 0.5 mm thick silicon oxide film is formed by sputtering on a cleaned blue plate glass, a photoresist is formed. (AZ1370 Hoechst Co., Ltd.) was spin-coated with a spinner and baked, and then the photomask image was exposed and developed to form a resist pattern for the lower wiring 102, and the Au / Cr deposited film was wet etched to obtain a desired shape. The lower wiring 102 is formed (FIG. 15A).
[0196]
Step-b
Next, an interlayer insulating layer 171 made of a silicon oxide film having a thickness of 1.0 μm is deposited by RF sputtering (FIG. 15B).
[0197]
Step-c
A photoresist pattern for forming the contact hole 172 is formed in the interlayer insulating layer 171 deposited in the step-b, and the interlayer insulating layer 171 is etched using this as a mask to form the contact hole 172 (FIG. 15C). .
[0198]
Step-d
Thereafter, a pattern to be the gap L between the device electrode 2 and the device electrode is formed with a photoresist (RD-2000N-41 manufactured by Hitachi Chemical Co., Ltd.), and by sputtering, Ti with a thickness of 5 nm and Pt with a thickness of 0.1 mm are formed. Deposited sequentially. The photoresist pattern was dissolved with an organic solvent, the Pt / Ti deposited film was lifted off, and element electrodes 2 and 3 having an element electrode interval L = 3 mm and an element electrode width W = 0.3 mm were formed (FIG. 15 (d )).
[0199]
Step-e
After forming the photoresist pattern of the upper wiring 103 on the device electrodes 2 and 3, Ti having a thickness of 5 nm and Au having a thickness of 0.5 mm are sequentially deposited by vacuum deposition, and unnecessary portions are removed by lift-off, An upper wiring 103 having a desired shape was formed (FIG. 16A).
[0200]
Step-f
A Cr film 191 having a thickness of 0.1 mm is deposited and patterned by vacuum deposition, and an organic palladium compound solution (ccp4230 manufactured by Okuno Seiyaku Co., Ltd.) is spin-coated with a spinner on the film, and is heated and baked at 300 ° C. for 10 minutes. ((B) of FIG. 16). The conductive thin film 4 made of fine particles of Pd as the main element thus formed had a thickness of 10 nm and a sheet resistance value of 2 × 10 4 Ω / □.
[0201]
Process-g
The Cr film 191 and the fired conductive thin film 4 were etched with an acid etchant and lifted off to form the conductive thin film 4 having a desired pattern (FIG. 16C).
[0202]
Step-h
A pattern for applying a resist was formed on portions other than the contact hole 172, and 5 nm thick Ti and 0.5 mm thick Au were sequentially deposited by vacuum evaporation. The contact hole 172 was filled by removing unnecessary portions by lift-off ((d) in FIG. 16).
[0203]
Through the above steps, the lower wiring 102, the interlayer insulating layer 171, the upper wiring 103, the device electrodes 2 and 3, and the conductive thin film 4 were formed on the insulating substrate 1.
[0204]
Next, an example in which an electron source and a display device are configured using the electron source substrate manufactured as described above will be described with reference to FIGS.
[0205]
After the substrate 1 on which the element was manufactured as described above was fixed on the rear plate 111, the face plate 116 (a fluorescent film 114 and a metal back 115 were formed on the inner surface of the glass substrate 113, 5 mm above the substrate 1). The frit glass was applied to the joint portion of the face plate 116, the support frame 112, and the rear plate 111, and sealed by baking at 400 ° C. for 10 minutes in the atmosphere. The substrate 1 was also fixed to the rear plate 111 with frit glass.
[0206]
In this embodiment, reference numeral 104 in FIG. 10 denotes an electron-emitting device (for example, corresponding to FIG. 4B) before forming an electron-emitting portion, and reference numerals 102 and 103 denote element wirings in the X direction and Y direction, respectively.
[0207]
In the case of monochrome, the phosphor film 114 is made of only a phosphor, but in this embodiment, the phosphor has a stripe shape. First, black stripes were formed, and phosphors of each color were applied to the gaps to produce the phosphor film 114. A material mainly composed of graphite, which is commonly used as a black stripe material, was used. A slurry method was used as a method of applying the phosphor on the glass substrate 113.
[0208]
A metal back 115 is usually provided on the inner surface side of the fluorescent film 114. The metal back was produced by performing a smoothing process (usually called filming) on the inner surface of the phosphor film after producing the phosphor film, and then vacuum-depositing Al.
[0209]
The face plate 116 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 114 in order to further increase the conductivity of the fluorescent film 114. However, in this embodiment, the metal plate alone is sufficient for conducting. I omitted it because it was good.
[0210]
When performing the above-described sealing, in the case of a color, each color phosphor must correspond to the electron-emitting device, so that sufficient alignment was performed.
[0211]
The atmosphere in the glass container completed as described above is exhausted by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, electrons are emitted through the external terminals Doxl to Doxm and Doyl to Doyn. A voltage was applied between the electrodes 2 and 3 of the element 104 to form the conductive thin film 4. The voltage waveform of the forming process is the same as (b) of FIG. The maximum voltage applied during forming was about 5V.
[0212]
In this example, T1 was set to 1 msec, T2 was set to 10 msec, and the process was performed in a vacuum atmosphere of about 1.3 × 10 −3 Pa.
[0213]
Next, after exhausting until the pressure in the panel reaches the 10-6 Pa level, tolunitrile is introduced into the panel from the exhaust pipe of the panel so that the total pressure becomes 1.3 × 10 −4 Pa and maintained. did. A voltage similar to that of FIG. 7 is applied between the electrodes 2 and 3 of the electron-emitting device 104 through the container outer terminals Doxl to Doxm and Doyl to Doyn, with a waveform similar to that in FIG. Retained. The activation process was performed with the device electrode 2 set to 0 V and the maximum voltage applied to the device electrode 3 set to 20 V.
[0214]
In this way, forming and activation processes were performed, and the electron-emitting device 104 was manufactured. Further, the activation was completed after confirming that the applied voltage was constant (20 V) and the device current corresponded to the region II in FIG.
[0215]
Next, the entire panel is evacuated while being heated to 250 ° C., the temperature is lowered to room temperature and the inside is set to a pressure of about 10 −7 Pa, and then the exhaust pipe (not shown) is welded by heating with a gas burner. Sealing was performed.
[0216]
Finally, in order to maintain the pressure after sealing, getter treatment was performed by a high-frequency heating method.
[0217]
In the image display device of the present invention completed as described above, a scanning signal and a modulation signal are applied to each electron-emitting device from the signal generation means (not shown) through the external terminals Doxl to Doxm and Doyl to Doyn, respectively. Thus, electrons are emitted, a high voltage of 5 kV or higher is applied to the metal back 115 or the transparent electrode (not shown) through the high-voltage terminal 117, the electron beam is accelerated, collides with the fluorescent film 114, and is excited and emitted. The image was displayed with.
[0218]
The image display apparatus in the present example was able to display a stable and good image with high brightness over a long period of time.
[0219]
(Example 4)
In this embodiment, an example of a display device configured to be able to display image information provided from various image information sources such as television broadcasting is shown. The image forming apparatus shown in FIG. 10 was displayed according to an NTSC television signal using the drive circuit shown in FIG.
[0220]
In this display device, the depth of the display device can be reduced because the display panel using the surface conduction electron-emitting device as an electron beam source can be easily thinned. In addition, a display panel using a display-conduction electron-emitting device as an electron beam source is easy to enlarge, has high brightness, and excellent viewing angle characteristics. It is possible to display with high visibility.
[0221]
The display device in this example was able to display a TV image according to the NTSC TV signal satisfactorily and stably.
[0222]
【The invention's effect】
According to the present invention described above, since the conductivity of the film containing carbon increases toward the first gap portion, the potential distribution change near the electron emission portion is reduced, and thus the first When the electron-emitting device is driven across the gap, the amount of electrons that fall into the carbon-containing film, conductive thin film, or device electrode to which a higher voltage is applied and are absorbed and become part of the device current is reduced. While decreasing, the emission current increases and the electron emission efficiency improves.
[0223]
In addition, since the substrate in the first gap has a recess, depending on the depth of the recess, the creepage distance between the carbon films facing each other across the gap is increased, so that the device current is suppressed. A high-efficiency element was obtained, and at the same time, a stable element was obtained in which deterioration of characteristics, which appears to be caused by the discharge phenomenon between the gaps, was suppressed even under a strong electric field applied between the carbon-containing films.
[0224]
Further, although it is presumed that the surface of the base exposed between the first gaps is exposed to the emitted electrons, in the element of the present invention, at least the surface of the concave part of the substrate exposed in the gaps. Because it contains carbon, fluctuations and deterioration in device characteristics, which can be attributed to reduced charge on the concave surface of the substrate caused by this electron irradiation, are suppressed, and a device with stable electron emission characteristics can be obtained over a long period of time. It was.
[0225]
Furthermore, in an electron source or an image forming apparatus using an element having high efficiency and stable characteristics for a long time according to the present invention, it is very stable even when a large number of electron-emitting elements are arranged. In the image display device using, an image display device having high luminance, stable for a long time and low power consumption was obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view of an electron-emitting device according to the present invention.
FIG. 2 is an enlarged schematic view of the vicinity of an electron emission portion of the present invention.
FIG. 3 is a schematic diagram showing an example of a vacuum processing apparatus having a measurement evaluation function.
FIG. 4 is a schematic view showing a part of the manufacturing process of the electron-emitting device of the present invention.
FIG. 5 is a schematic diagram showing an example of a voltage waveform that can be used in a forming process that is a part of the manufacturing process of the electron-emitting device of the present invention.
FIG. 6 is a schematic view showing an activation process which is a part of the manufacturing process of the electron-emitting device of the present invention.
FIG. 7 is a schematic diagram showing an example of a voltage waveform that can be used in an activation process which is a part of the manufacturing process of the electron-emitting device of the present invention.
FIG. 8 is a schematic diagram showing the relationship between the emission current Ie, device current If, and device voltage Vf of the electron-emitting device of the present invention.
FIG. 9 is a schematic view showing an example in which the electron-emitting device of the present invention is applied to an electron source arranged in a simple matrix.
FIG. 10 is a schematic view showing an example in which the electron-emitting device of the present invention is applied to an image forming apparatus.
FIG. 11 is a schematic view showing an example of a fluorescent film.
FIG. 12 is a block diagram of a driving circuit for performing display in accordance with an NTSC television signal when the electron-emitting device of the present invention is applied to an image forming apparatus.
FIG. 13 is a schematic view showing an example in which the electron-emitting device of the present invention is applied to an electron source arranged in a simple matrix.
14 is a partial cross-sectional schematic view taken along a polygonal line AA ′ in FIG. 13;
FIG. 15 is a schematic view for explaining a part of the manufacturing process of the electron source according to the embodiment of the present invention.
FIG. 16 is a schematic diagram for explaining a part of the manufacturing process of the electron source according to the embodiment of the present invention.
FIG. 17 is a schematic view showing a configuration of a conventional electron-emitting device.
FIG. 18 is a schematic view showing a configuration of another conventional electron-emitting device.
FIG. 19 is a schematic diagram showing changes in device current during the activation process of the present invention.
FIG. 20 is an enlarged schematic view of the vicinity of the electron emission portion of the present invention.
[Explanation of symbols]
1 Substrate
2, 3 element electrodes
4 Conductive thin film
5 Electron emission part
6 Carbon or carbon compounds
7 Gap (second gap)
8 Gap (first gap)
21, 22 Deposit (carbon-containing film)
23 recess
30 Ammeter
31 Power supply
32 Ammeter
33 Voltage power supply
34 Anode electrode
101 Electron source substrate
102 X direction wiring
103 Y-direction wiring
104 Electron emitting device
111 Rear plate
112 Support frame
113 Glass substrate
114 phosphor film
115 metal back
116 face plate
117 High voltage terminal
118 Envelope
121 Black member
122 phosphor
131 Display panel
132 Scanning circuit
133 Control circuit
134 Shift register
135 line memory
136 Sync signal separation circuit
137 Modulation signal generator
Vx, Va DC power supply
171 Interlayer insulation layer
172 Contact hole

Claims (9)

A pair of electrodes disposed on the surface of the substrate;
A film having a pair of carbons separated by a first gap,
One of the pair of carbon-containing films is electrically connected to one of the pair of electrodes, and the other of the pair of carbon-containing films is electrically connected to the other of the pair of electrodes. An element,
The conductivity of each of the pair of carbon-containing films is increased from the pair of electrodes toward the first gap portion ,
In the cross section perpendicular to the substrate surface including the first gap portion, the pair of carbon-containing films at a position farther from the substrate surface than the distance between the pair of carbon-containing films on the substrate surface An electron-emitting device characterized in that the distance between is narrower . A pair of electrodes disposed on the surface of the substrate;
A film having a pair of carbons separated by a first gap,
One of the pair of carbon films is electrically connected to one of the pair of electrodes, and the other of the pair of carbon films is electrically connected to the other of the pair of electrodes. An element,
The conductivity of each of the pair of carbon-containing films is increased from the pair of electrodes toward the first gap portion,
The base surface has a recess in the first gap,
An electron-emitting device having carbon in the recess. 3. The electron according to claim 1, wherein each of the pair of carbon-containing films is electrically connected to the electrode through a conductive thin film disposed between the pair of electrodes. Emitting element. The conductive thin film have a second gap between the pair of electrodes, electrons according to claim 3, wherein said first gap portion to the second in the gap portion is arranged Emitting element. The electron-emitting device according to claim 3 or 4 , wherein the conductive thin film is made of a Pd fine particle film. The electron-emitting device is an electron-emitting device that emits electrons by applying a voltage between the pair of electrodes such that a potential of one electrode of the pair of electrodes is higher than a potential of the other electrode, Present on an extension of a line connecting one end of the pair of carbon-containing films forming the narrowest portion of the first gap and the other end of the pair of carbon-containing films, the pair of film thickness with a carbon connecting the one electrode of the membrane with a carbon electron-emitting device according to any one of claims 1 to 5, characterized in that at 1 nm or less. Electron source the electron emission device according to any one of claims 1 to 6 and arrayed formed on a substrate, characterized in that it releases at least than one electron of the electron emission device in accordance with an input signal. 8. An image forming apparatus comprising: the electron source according to claim 7 ; and an image forming member that forms an image by irradiating electrons emitted from the electron source. 9. A television broadcast display device comprising: an image forming device; and a circuit for displaying a television broadcast signal on the image forming device, wherein the image forming device is the image forming device according to claim 8. A display device for television broadcasting, characterized in that there is.

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