JP2010033929A - Electron-emitting element, method of manufacturing the same, and image display device - Google Patents

Abstract

An electron-emitting device having excellent electron-emitting characteristics is provided by forming a gap uniformly and with low power in an electron-emitting region forming film mainly composed of carbon.
An electrode portion 2 having a pair of electrodes 3a and 3b and an electron emission portion forming film 4 sandwiched between the electrodes is formed on a substrate 1, and an energization process is performed between the electrodes. An electron-emitting device in which a gap 5 is formed in the electron-emitting portion forming film 4, wherein the electron-emitting portion forming film 4 is made of metal and carbon, and the content of the metal is 1 to 20 atom%, and The metal is a mixed film in the form of fine particles having a diameter of 1 to 5 nm, and the density ratio of the mixed film to the bulk is 0.7 or more and 1.0 or less.
[Selection] Figure 1

Description

  The present invention relates to a surface conduction electron-emitting device used for a flat panel display and a manufacturing method thereof, and further relates to an image display device using the electron-emitting device.

  The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel to the film surface. As a typical configuration, a pair of electrodes and an electron emission portion forming film communicating between the electrodes are formed on a substrate, and a gap is formed in the electron emission portion forming film by an energization process called energization forming. Is. When a voltage is applied between the pair of electrodes in this configuration, electrons are emitted from the gap.

  As the method for producing the electron emission portion forming film, conventionally, a sputtering method, a vapor deposition method, a method of applying an organic metal-containing solution by spinner coating, patterning, thermal decomposition, an inkjet method, and a solution of an organic metal-containing solution on a substrate. A method of applying droplets and heating has been proposed.

  Above all, sputtering has been put into practical use for large-screen displays such as liquid crystal display devices and plasma displays, and has matured as a technology for increasing the area, making it easier to stably obtain a uniform film. .

Examples of the electron emission portion forming film include an Au thin film, an In ₂ O ₃ / SnO ₂ thin film, a carbon thin film, and a Pd film. Patent Document 1 includes a mixed film of a metal or a metal compound and carbon. Yes. In particular, a film mainly composed of carbon is expected to obtain excellent electron emission characteristics such as driving stability because of its high heat resistance.

JP 2006-491171 A

  Although an electron emission portion forming film mainly composed of carbon is expected to have excellent electron emission characteristics, it has not been practically used so far. The reason is its excellent heat resistance. As described above, in the surface conduction electron-emitting device, it is common to form a gap serving as an electron emission portion in advance in the electron emission portion forming film by an energization process called energization forming before electron emission. The energization forming is a phenomenon in which when a thin film is energized, a high current density is generated in the thin film, and a gap is formed in the thin film by the Joule heat.

  However, because the carbon thin film has high heat resistance, gaps are not easily formed in the thin film even when energized, and even if gaps can be formed, a large amount of power is required or a large amount of power is used. Problems such as turning over and non-uniform width of the gap may occur.

  The present invention solves such a problem, and uniformly forms a gap at a low power with an electron emitting portion forming film mainly composed of carbon, so that an electron emitting device having excellent electron emitting characteristics can be formed uniformly and It is intended to provide at a low manufacturing cost. Furthermore, it aims at providing the image display apparatus excellent in image quality using this electron-emitting element.

  According to a first aspect of the present invention, an electrode portion having a pair of electrodes and an electron emission portion forming film sandwiched between the electrodes is formed on a substrate, and an electric conduction process is performed between the electrodes, whereby the electron emission is performed. An electron-emitting device in which a gap is formed in a part forming film, wherein the electron-emitting part forming film is made of metal and carbon, the metal content is 1 to 20 atom%, and the metal has a diameter of 1 to 5 nm. The mixed film is in the form of fine particles, and the density ratio of the mixed film to the bulk is 0.7 or more and 1.0 or less.

The electron-emitting device of the present invention includes the following configuration as a preferred embodiment.
The metal contained in the electron emission portion forming film is one or more selected from the group consisting of Ni, Co, Pd, Pt, Ir, and Rh.
The thickness of the electron emission portion forming film is 5 nm or more and 50 nm or less.

According to a second aspect of the present invention, an electron part having a pair of electrodes and an electron emission part forming film sandwiched between the electrodes is formed on a substrate, and an electric current treatment is performed between the electrodes, whereby the electron emission is performed. A method of manufacturing an electron-emitting device that forms a gap in a part formation film,
The electron emission portion forming film is a mixed film made of metal and carbon, the metal content is 1 to 20 atom%, and the metal is in the form of fine particles having a diameter of 1 to 5 nm, The density ratio with respect to the bulk is 0.7 or more and 1.0 or less.

The manufacturing method of the electron-emitting device of the present invention includes the following configuration as a preferred embodiment.
The metal contained in the electron emission portion forming film is one or more selected from the group consisting of Ni, Co, Pd, Pt, Ir, and Rh.
The thickness of the electron emission portion forming film is 5 nm or more and 50 nm or less.
The electron emission portion forming film is formed by sputtering, and the pressure in the chamber during sputtering is 1.0 Pa or more.
In energization processing for forming a gap in the electron emission portion forming film, the rate of change before and after the energization processing of at least one half width of carbon G band and D band in visible light Raman spectroscopy of the electron emission portion formation film The energization process is performed so that the current becomes 80% to 120%.
In energization processing for forming a gap in the electron emission portion forming film, the half width after energization processing of at least one of carbon G band and D band in visible light Raman spectroscopy of the electron emission portion formation film is energization processing. The energization process is performed so that the previous 80% is obtained.

  According to a third aspect of the present invention, there is provided an electron source comprising a plurality of the electron-emitting devices of the present invention and a plurality of wirings for applying a voltage to the electron-emitting devices, and emitting from the electron-emitting devices of the electron source And an opposing substrate provided with a light emitting member that emits light when irradiated with emitted electrons.

  According to the present invention, although it is a film mainly composed of carbon having high heat resistance, it is possible to form a gap in the electron emission portion forming film with low power, there is little variation in electrical characteristics, and excellent electron emission characteristics. It is possible to provide an electron-emitting device having low cost. Therefore, an image display device with high image quality display can be provided using the electron-emitting device.

  As described above, it is difficult to form a gap by energization forming because the electron emission portion forming film mainly composed of carbon has high heat resistance. As a means to improve this, a method of making it easy to form gaps by energization forming by forming an electron emission part formation film mainly composed of carbon with a low bulk density ratio and reducing its structural mechanical strength Can be considered.

  Here, the bulk density ratio refers to a value obtained by dividing the measured density value of the thin film by the density of the bulk body having the same composition.

  However, in this method, the heat resistance of the electron emission portion forming film after the formation of the gap is also lowered, and the obtained electron emission characteristics are not sufficient.

  The present inventors rather formed an electron emission portion forming film mainly composed of carbon at a high bulk density ratio of 0.7 to 1.0, and further contains a metal at a composition ratio of 1 to 20 atom%. The metal was contained in the form of fine particles having a diameter of 1 to 5 nm. As a result, it has been found that an electron-emitting device having excellent electron-emitting characteristics such as driving stability can be obtained uniformly and at low manufacturing cost by forming a good gap with low power in the electron-emitting portion forming film. .

  Moreover, as a manufacturing method of an electron emission part formation film, the organic metal containing solution is provided on a board | substrate with a spinner or the inkjet method as mentioned above, the method of heating, a vapor deposition method, etc. are used. However, in the present invention, it is preferable to manufacture the electron emission portion forming film by sputtering.

  The sputtering method is generally a film forming method in which atoms and / or particles sputtered from a certain direction are deposited on a substrate on which a film is formed. That is, by depositing atoms and / or particles from a certain method, it is possible to give the formed film different continuity in the parallel and perpendicular directions to the substrate. In particular, by setting the pressure in the chamber at the time of sputtering to a high pressure region of 1.0 Pa or more, the obtained film can form a columnar structure having higher continuity in the direction perpendicular to the substrate than in the parallel direction.

  Even if this columnar structure has a high bulk density as a whole film, since the continuity of atomic arrangement is low in the direction parallel to the substrate, gaps can be formed with relatively low power. Therefore, in the present invention, the electron emission portion forming film is preferably formed by sputtering, and the pressure in the chamber during sputtering is preferably set to a pressure of 1.0 Pa or more.

  In the present invention, the film thickness of the electron emission portion forming film is preferably 5 nm or more and 50 nm or less. However, when the electron emission portion forming film has a thickness of less than 5 nm, the resistance value is likely to vary. This is because the characteristics of the obtained electron-emitting devices are also likely to vary. On the other hand, if the film thickness is 50 nm or more, the mechanical strength of the film in the direction parallel to the substrate increases, which makes it difficult to form a gap during energization forming, or the resistance value is too low to form a gap during energization forming. A lot of power is required.

  In the present invention, in order to form a gap in the electron emission portion forming film, the electron emission portion is subjected to energization processing called energization forming. In the present invention, it is also preferable to form a gap so that the change rate of at least one of the half-value widths of the G band and D band of carbon in the visible light Raman spectroscopy before and after the energization treatment is 80% to 120%. one of.

  This corresponds to forming gaps in the course of the energization treatment while relatively changing the SP2 and / or SP3 bonding properties of carbon. In the process of energization treatment, the element is exposed to Joule heat, so that the crystallinity increases and the resistance decreases when the carbon bonding property changes. If the crystallinity increases, the mechanical strength of carbon also increases and it becomes difficult to form gaps. In addition, when the resistance of the electron emission portion forming film is reduced, the current during the energization process is increased, and as a result, a large amount of power is consumed. Therefore, from the viewpoint of reducing environmental burden and manufacturing cost, it is one of preferred embodiments that the gap is formed so that the rate of change of the full width at half maximum before and after the energization process is 80% to 120%.

  In the present invention, it is also one of preferred embodiments that the gap is formed so that the rate of change of the half-value width is less than 80% after the energization process of the electron emission portion forming film as compared to before the energization process. .

  This corresponds to the fact that the carbon is greatly modified during the energization process to become carbon with higher crystallinity. The electron emission portion forming film mainly composed of carbon having high crystallinity has higher heat resistance, and the temporal stability of electron emission is improved. At the same time, when the crystallinity related to the SP2 bond derived from the G band increases, it is expected that π-electrons that are not easily bound to the nucleus increase and the amount of electron emission increases.

  Therefore, from the viewpoint of the stability of electron emission over time and the increase in the amount of electron emission, it is also possible to form the gap so that the change rate of the half width is less than 80% after the energization process and before the energization process. This is one of the preferred embodiments.

In the present invention, the following actions are required for the metal contained in the electron emission portion forming film.
(1) Forming fine particles with a diameter of 1 to 5 nm in a carbon matrix to assist gap formation during energization forming.
(2) The resistance of the electron emission portion forming film can be adjusted by increasing or decreasing the content.
(3) It is difficult to form foreign particles such as coarse particles during sputtering.
(4) The ability to adjust carbon binding during energization treatment.

  As a result of intensive studies by the present inventors, the metal contained in the electron emission portion forming film is one or more selected from the group consisting of Ni, Co, Pd, Pt, Ir, and Rh. Was found to be preferable. More preferably, Ni or Co or Pd, or a combination thereof.

  In the present invention, the electron emission portion forming film before energization forming is a mixed film made of metal and carbon of 1 to 20 atom%, and the metal is in the form of fine particles having a diameter of 1 to 5 nm, and the density of the mixed film with respect to the bulk The ratio may be from 0.7 to 1.0. Further, for reasons such as resistance adjustment, control of crystallinity, removal of adsorbate, etc., energization forming may be performed after firing in a vacuum environment after film formation. The temperature at the time of firing may be any number of times as long as it is within the constraint that the substrate is not deformed, but is preferably 550 ° C. or lower. If the temperature during firing is too high, the carbon will be modified during firing, resulting in decreased structural anisotropy formed by sputtering, etc., or excessive increase in the mechanical strength of the carbon. It may be difficult to form the gap uniformly during forming.

  Exemplary embodiments of an electron-emitting device according to the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to them.

  1A and 1B schematically show a preferred embodiment of the electron-emitting device of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line A-A ′ of FIG. In the figure, 1 is a substrate, 2 is an electrode portion, 3a and 3b are electrodes, 4 is an electron emission portion formation film, and 5 is a gap formed in the electron emission portion formation film.

  The electron-emitting device of the present invention has a pair of electrodes 3a and 3b on the substrate 1 and an electron-emitting portion forming film 4 sandwiched between the electrodes 3a and 3b. A gap 5 that is an electron emission portion is formed.

Examples of the substrate 1 include quartz glass, glass with reduced impurity content such as Na, blue plate glass, a glass substrate with SiO ₂ formed on the surface, and a ceramic substrate such as alumina. If necessary, the substrate is sufficiently cleaned, and then the substrate surface is hydrophobized using a silane coupling agent.

Materials for the electrodes 3a and 3b include Pd, Pt, Ru, Ag, Au, Ti, In, Cu, Cr, Fe, Zn, Sn, Ta, W, Pb, and other metals, PdO, SnO ₂ , In ₂ O ₃ and oxides such as PbO and Sb ₂ O ₃ . _{Further, HfB 2, ZrB 2, LaB} 6, CeB 6, YB 4, GdB borides such as _{4, TiC, ZrC, HfC,} TaC, SiC, and WC, etc., TiN, ZrN, nitrides such as HfN, Si , Semiconductors such as Ge, carbon and the like.

  The distance L between the electrode pairs 3a and 3b is several hundred to several hundred μm. Further, it is desirable that the voltage applied between the electrode pair is low, and it is required to produce the electrode with good reproducibility. Therefore, the preferable interval L is several hundreds of μm to several μm.

  As described above, Ni, Co, Pd, Pt, Ir, and Rh are preferably used for the electron emission portion forming film 4. In addition to the RF sputtering method, the DC sputtering method, and the vapor deposition method, the formation can be performed by any method such as a spin coating method, a dipping method, and an ink jet method. In the present invention, the sputtering method is used. In particular, it is preferable to use an RF sputtering method.

  Moreover, when the method of apply | coating the solution containing an organic compound etc. is used, it is necessary to change an organic compound film into inorganic carbon. There are no particular restrictions on the means used for this, but a method of heating in a vacuum environment is preferred. The heating temperature is 250 ° C. or higher and 550 ° C. or lower, preferably 350 ° C. or higher and 550 ° C. or lower.

  Next, an energization process called energization forming for forming a gap to be an electron emission portion is performed on the electron emission portion forming film 4 manufactured as described above.

  In energization forming, a gap (crack) 5 having a changed structure is formed in the electron emission portion forming film 4 by energizing a power source (not shown) between the electrodes 3a and 3b of the electrode portion 2 under a predetermined degree of vacuum. It is a process to form.

  An example of a voltage waveform applied between the electrodes 3a and 3b in the energization forming is shown in FIG. The voltage waveform is particularly preferably a pulse waveform. For this purpose, there are a method shown in FIG. 2A in which a pulse having a pulse peak value as a constant voltage is continuously applied, and a method shown in FIG. 2B in which a pulse is applied while increasing the pulse peak value. is there.

  First, the case where the pulse peak value is a constant voltage will be described with reference to FIG. T1 and T2 in FIG. 2A are the pulse width and pulse interval of the voltage waveform. Usually, T1 is set in the range of 1 μsec to 10 msec, and T2 is set in the range of 10 μsec to 100 msec. The peak value of the triangular wave (peak voltage during energization forming) is appropriately selected according to the form of the electron-emitting device. Under such conditions, for example, a voltage is applied for several seconds to several tens of minutes. The pulse waveform is not limited to a triangular wave, and a desired waveform such as a rectangular wave can be adopted.

  Next, the case where a voltage pulse is applied while increasing the pulse peak value will be described with reference to FIG. T1 and T2 in FIG. 2B can be the same as those shown in FIG. The peak value of the triangular wave (peak voltage during energization forming) can be increased by, for example, about 0.1 V step.

  The end of the energization forming process can be completed when the resistance value is obtained by measuring the current flowing through the element to which the pulse voltage is applied, and the energization forming can be terminated when a resistance of, for example, 1 MΩ or more is indicated.

  As described above, the electron emission efficiency from the gap 5 formed by the energization forming is still very low under the current conditions. Therefore, it is preferable to apply an energization process called activation as will be described later.

  In this activation treatment, carbon or a carbon compound derived from the carbon-containing gas is obtained by repeatedly applying a pulse voltage between the electrodes 3a and 3b under an appropriate vacuum degree in an atmosphere containing the carbon-containing gas. In this process, a carbon film is deposited in the vicinity of the gap 5.

In this step, for example, tolunitrile is used as a carbon source and is introduced into the vacuum space through a slow leak valve to maintain about 1.3 × 10 ⁻⁴ Pa. The pressure of tolunitrile to be introduced is slightly affected by the shape of the vacuum apparatus and the members used in the vacuum apparatus, but is preferably about 1 × 10 ⁻⁵ Pa to 1 × 10 ⁻² Pa.

  FIG. 3 shows a preferred example of voltage application used in the activation process. The maximum voltage value to be applied is appropriately selected in the range of 10 to 20V.

  In FIG. 3A, T1 is a positive and negative pulse width of the voltage waveform, T2 is a pulse interval, and the positive and negative absolute values of the voltage value are set equal. In FIG. 3B, T1 and T1 ′ are the positive and negative pulse widths of the voltage waveform, T2 is the pulse interval, and T1> T1 ′, and the voltage values are set to have the same positive and negative absolute values. .

  In this process, energization is stopped when the emission current Ie reaches almost saturation, the slow leak valve is closed, and the activation process is terminated.

  A stabilization process is preferably performed on the electron-emitting device obtained through the above-described processes.

This step is unnecessary organic from the electron-emitting device and the surface of the surrounding substrate 1 in an atmosphere of a high degree of vacuum (a vacuum degree higher than the degree of vacuum in the activation process when the activation process is performed). It is a step of removing a substance. As the degree of vacuum, the partial pressure of the organic substance is preferably 10 ⁻⁶ Pa or less, more preferably 10 ⁻⁸ Pa or less. The total pressure is preferably as low as possible, practically preferably 10 ⁻⁵ Pa or less, more preferably 10 ⁻⁶ Pa or less.

  Through the above steps, the electron-emitting device as shown in FIG. 1 can be manufactured.

  The basic characteristics of the electron-emitting device manufactured by the device configuration and manufacturing method as described above will be described with reference to FIGS.

  FIG. 4 is a schematic diagram of a measurement evaluation apparatus for measuring the electron emission characteristics of the electron-emitting device having the above-described configuration. In FIG. 4, 11 is a power source for applying the element voltage Vf to the element, 10 is an ammeter for measuring the element current If flowing through the electrode part of the element, and 14 is an emission current emitted from the electron emission part of the element. It is an anode electrode for capturing Ie. Reference numeral 13 denotes a high voltage power source for applying a voltage to the anode electrode 14, and reference numeral 12 denotes an ammeter for measuring the emission current Ie emitted from the electron emission portion of the device.

  In measuring the device current If flowing between the electrodes 3a and 3b of the electron-emitting device and the emission current Ie to the anode, a power source 11 and an ammeter 10 are connected to the electrodes 3a and 3b, and above the electron-emitting device. An anode electrode 14 connecting the power source 13 and the ammeter 12 is disposed.

  The electron-emitting device and the anode electrode 14 are installed in a vacuum device 15, and the vacuum device includes equipment necessary for the vacuum device such as an exhaust pump 16 and a vacuum gauge. The device can be measured and evaluated. The voltage of the anode electrode 14 was measured in the range of 1 kV to 10 kV, and the distance H between the anode electrode 14 and the electron-emitting device was measured in the range of 2 mm to 8 mm.

  FIG. 5 shows a typical example of the relationship between the emission current Ie and device current If measured by the measurement evaluation apparatus shown in FIG. 4 and the device voltage Vf. Although the emission current Ie and the device current If are remarkably different in magnitude, in FIG. 5, the vertical axis is expressed in arbitrary units on a linear scale for qualitative comparison of changes in If and Ie.

  The electron-emitting device of the present invention has three characteristics with respect to the emission current Ie.

  First, as is apparent from FIG. 5, when an element voltage higher than a certain voltage (referred to as a threshold voltage, Vth in FIG. 5) is applied to this element, the emission current Ie increases rapidly. The emission current Ie is hardly detected below the threshold voltage Vth. That is, it can be seen that the characteristics as a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie are shown.

  Second, since the emission current Ie depends on the element voltage Vf, the emission current Ie can be controlled by the element voltage Vf.

  Third, the emitted charge captured by the anode electrode 14 depends on the time for applying the device voltage Vf. That is, the amount of charge trapped by the anode electrode 14 can be controlled by the time during which the device voltage Vf is applied.

  Next, an electron source and an image display device according to the present invention will be described.

  FIG. 6 is a schematic view showing an embodiment of an electron source in which a plurality of electron-emitting devices according to the present invention are arranged on a substrate, in which 21 is a substrate, 22 is an X-direction wiring (upper wiring), 23 Is a Y-direction wiring (lower wiring), and 24 is an electron-emitting device.

  The electron source of this example is formed by connecting a plurality of electron-emitting devices 24 in a matrix on a substrate 21. The configuration of each electron-emitting device is the same as that shown in FIG.

  In the manufacture of such an electron source, when the electrode portion 2 is formed, at least a part of the wiring can be formed simultaneously. For example, in the case of an electron source configured as shown in FIG. 15 to be described later, the electrode 3b of each element and the Y-direction wiring 23 can be formed simultaneously.

  An example of an image display device using the electron source having the simple matrix arrangement as described above will be described with reference to FIG. FIG. 7 is a perspective view schematically showing a configuration of a display panel as an example of the image display apparatus of the present invention, and shows a state in which a part is cut away.

  In FIG. 7, reference numeral 31 denotes a substrate on which the electron source substrate 21 is mounted, and 32 denotes a fluorescent film 34 as a light emitting member that emits light upon irradiation of electrons emitted from the electron-emitting device on the inner surface of a glass substrate 33, a metal back 35, and the like. Face plate (counter substrate). Reference numeral 36 denotes a support frame. The substrate 31, the support frame 36, and the face plate 32 are adhered by frit glass and sealed at a temperature of 400 to 500 ° C. for 10 minutes or more to form an envelope 37.

  In addition, by installing a support body (not shown) called a spacer between the face plate 32 and the electron source substrate 21, an envelope 37 having sufficient strength against atmospheric pressure even in the case of a large area panel. Can also be configured.

  FIG. 8 is an explanatory diagram of the fluorescent film 34 provided on the face plate 32. The phosphor film 34 is composed of only the phosphor 42 in the case of monochrome, but in the case of a color phosphor film, the phosphor film 34 is composed of a black conductor 41 and a phosphor 42 called a black stripe or a black matrix depending on the arrangement of the phosphors 42. Is done. The purpose of providing the black stripes and the black matrix is to make the mixed colors and the like inconspicuous by blackening the divided portions between the phosphors 42 of the three primary color phosphors necessary for color display. In addition, a decrease in contrast due to reflection of external light in the fluorescent film 44 is suppressed.

  A metal back 35 is usually provided on the inner surface side of the fluorescent film 34. The purpose of the metal back 35 is to improve the luminance by specularly reflecting the light emitted from the phosphor toward the inner surface to the face plate 32 side. Also, it acts as an anode electrode for applying an electron beam acceleration voltage. The metal back 35 can be fabricated by performing a smoothing process (usually called filming) on the inner surface of the phosphor film 34 after the phosphor film 34 is fabricated, and then depositing Al by vacuum evaporation or the like.

  When performing the above-mentioned sealing, in the case of a color, each color phosphor must correspond to the electron-emitting device, so that it is necessary to perform sufficient alignment by a method of abutting the upper and lower substrates.

The degree of vacuum at the time of sealing is required to be about 10 ⁻⁵ Pa, and a getter process may be performed to maintain the degree of vacuum after sealing the envelope 37. This heats a getter disposed at a predetermined position (not shown) in the envelope by a heating method such as resistance heating or high-frequency heating immediately before or after sealing the envelope 37, This is a process for forming a deposited film. The getter usually contains Ba or the like as a main component, and maintains the degree of vacuum by the adsorption action of the deposited film.

  According to the basic characteristics of the electron-emitting device of the present invention described above, the emitted electrons from the electron-emitting portion are controlled by the peak value and width of the pulse voltage applied between the opposing electrodes above the threshold voltage, The amount of current is also controlled by the intermediate value, so that halftone display is possible.

  In addition, when a large number of electron-emitting devices are arranged, a selection line is determined by the scanning line signal of each line, and if the pulse voltage is appropriately applied to each device through each information signal line, an appropriate voltage is applied to any device. It is possible to turn on each element.

  Examples of a method for modulating the electron-emitting device according to an input signal having a halftone include a voltage modulation method and a pulse width modulation method.

  A specific drive device will be described below.

  FIG. 9 shows a configuration example of an image display device for television display based on NTSC television signals using a display panel configured using an electron source substrate having a simple matrix arrangement.

  9, 51 is an image display panel as shown in FIG. 7, 52 is a scanning circuit, 53 is a control circuit, 54 is a shift register, 55 is a line memory, 56 is a synchronizing signal separation circuit, and 57 is an information signal generator. Va is a DC voltage source.

  A scanning circuit 52 of an X driver that applies a scanning line signal to the X direction wiring of the image display panel 51 using the electron source substrate 21 and an information signal generator of a Y driver to which an information signal is applied to the Y direction wiring. 57 is connected.

  In order to implement the voltage modulation method, a circuit that generates a voltage pulse of a certain length as the information signal generator 57 but appropriately modulates the peak value of the pulse according to the input data is used. In order to implement the pulse width modulation method, the information signal generator 57 generates a voltage pulse having a constant peak value, but appropriately modulates the width of the voltage pulse according to the input data. Is used.

  The control circuit 53 generates Tscan, Tsft, and Tmry control signals for each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 56.

  The synchronization signal separation circuit 56 is a circuit for separating a synchronization signal component and a luminance signal component from an NTSC television signal input from the outside. This luminance signal component is input to the shift register 54 in synchronization with the synchronization signal.

  The shift register 54 serially / parallel converts the luminance signal input serially in time series for each line of the image, and operates based on the shift clock Tsft sent from the control circuit 53. Data for one line of the serial / parallel converted image (corresponding to drive data for n electron-emitting devices) is output from the shift register 54 as n parallel signals.

  The line memory 55 is a storage device for storing data for one line of the image for a necessary time, and the stored contents are input to the information signal generator 57.

  The information signal generator 57 is a signal source for appropriately driving each of the electron-emitting devices in accordance with each luminance signal, and an output signal thereof enters the display panel 51 through the Y-direction wiring, and the scanning circuit 52 Is applied to each electron-emitting device at the intersection with the selected X-direction wiring.

  By sequentially scanning the X-direction wiring, it becomes possible to drive the electron-emitting devices on the entire surface of the panel.

  As described above, in the image display device according to the present invention, electrons are emitted by applying a voltage to each electron-emitting device through the XY direction wiring. On the other hand, an image is displayed by applying a high voltage to the metal back 35 which is an anode electrode through the high voltage terminal Hv connected to the DC voltage source Va, accelerating the generated electron beam and causing it to collide with the fluorescent film 34. Can do.

  The configuration of the image display device described here is an example of the image display device of the present invention, and various modifications can be made based on the technical idea of the present invention. Although the NTSC system is used for the input signal, the input signal is not limited to this, and the same applies to PAL, HDTV, and the like.

(Comparative Example 1)
An electron-emitting device having the basic configuration shown in FIG. 1 was produced.

As the substrate 1, a 2.8 mm thick glass of PD-200 (trade name, manufactured by Asahi Glass Co., Ltd.) with few alkali components is used, and a SiO ₂ film 100 nm is applied and fired thereon as a sodium block layer. Using.

  On the glass substrate 1, a titanium Ti film having a thickness of 5 nm and a platinum Pt film having a thickness of 40 nm are formed by sputtering, and a photoresist is applied and patterned by a series of photolithography methods of exposure, development, and etching to form electrodes 3 a, 3b was formed.

  In this example, the distance L between the element electrodes is 10 μm and the width W is 1000 μm.

  A photosensitive resin (methacrylic acid-methyl methacrylic acid-ethyl acrylate-n-butyl acrylate-azobisisobutyronitrile polymer) was applied on the entire surface of the substrate with a spin coater, and 10 ° C. at 100 ° C. on a hot plate. Dried for minutes.

Then, cover the electron-emitting portion forming film region by using a photomask, except the region at ultra-high pressure mercury lamp (illuminance = 8mW / cm ^2), Canon Inc. PLA501F L. Exposure was carried out at I = 8.0, and development was performed for 60 seconds by a paddle method using pure water to obtain a resin pattern.

The substrate on which the resin pattern was formed was put into a chamber of a depot-up type RF magnetron sputtering apparatus, and evacuated by a rotary pump and then a cryopump until the pressure became 5 × 10 ⁻⁵ Pa or less. As the sputtering target, an amorphous carbon target having a diameter of 8 inches was used, and a composition ratio of a film to be formed was adjusted by placing a palladium chip on the target.

  After reaching a predetermined pressure, argon gas was introduced into the chamber so that the pressure became 1.4 Pa, and sputtering was performed at an RF output of 300 W for 80 minutes.

  Next, the substrate is taken out from the RF magnetron sputtering apparatus, and the resist is peeled off by a paddle method for 5 minutes using a tetramethylammonium hydride aqueous solution (concentration: 2.38 mass%), and the pattern of the electron emission portion forming film 4 is formed. Obtained.

  In this example, the width W ′ of the electron emission portion forming film 4 is set to 100 μm.

The substrate thus formed was held in a vacuum chamber, and the electrodes 3a and 3b were connected to a probe so that energization treatment was possible from outside the chamber. Next, the inside of the chamber is evacuated by a turbo molecular pump and a scroll pump, and after evacuating until the pressure inside the chamber reaches 1 × 10 ⁻⁶ Pa or less, the triangular wave shown in FIG. 2B is applied between the electrodes 3a and 3b. A pulse voltage changed to a rectangular wave was applied. T1 = 0.1 ms and T2 = 50 ms. The voltage started from 1V, increased by 0.1V every 5 seconds, applied to 50V, and the voltage application was terminated. The electron-emitting device was obtained through the above steps.

Example 1
An electron-emitting device was obtained in the same manner except that the RF output in Comparative Example 1 was changed to 2400 W, the sputtering time was changed to 2 minutes and 30 seconds, and the size of the palladium chip was changed.

(Example 2)
An electron-emitting device was obtained in the same manner except that the size of the palladium chip in Example 1 was changed.

(Example 3)
An electron-emitting device was obtained in the same manner except that the palladium chip in Example 1 was changed to a nickel chip having a different size.

Example 4
An electron-emitting device was obtained in the same manner except that the sputtering time in Example 1 was changed to 55 seconds.

(Comparative Example 2)
An electron-emitting device was obtained in the same manner except that the size of the palladium chip in Example 1 was changed.

  The electron-emitting portion forming films of the electron-emitting devices of Comparative Examples 1 and 2 and Examples 1 to 4 were analyzed with an X-ray photoelectron spectroscopy analyzer (X-ray Photoelectron Spectroscopy = XPS). The density was measured by the X-ray reflectivity method.

  The bulk densities of palladium, nickel, and amorphous carbon were set to 11.99, 8.908, and 2.10, respectively, and the bulk density at the composition determined by X-ray photoelectron spectroscopic analysis was calculated from this and the atomic weight of each element. The bulk density ratio was obtained by dividing the density value obtained by the X-ray reflectance method by the bulk density.

  Sheet resistance was determined by a tester.

  As a result of observing the electron emission portion forming film of each example from the cross-sectional direction with a transmission electron microscope, it was confirmed that the metal fine particles were present in the form of fine particles having a diameter of 1 to 5 nm in the carbon film.

  Further, the gap formed in the electron emission portion forming film after forming was observed with an optical microscope and a scanning electron microscope, and it was confirmed whether the gap portion was formed uniformly and there was no abnormality such as film peeling.

  The results are shown in Table 1.

In Comparative Example 1, a resistance of 1.0 × 10 ⁷ Ω / □ or more was reached at an applied voltage of 31 V, but when observed with an optical microscope and a scanning electron microscope, there was a portion where the film near the gap was turned up. It was a non-uniform forming form. On the other hand, in Examples 1 to 4, no portion turned up in the vicinity of the gap was found, and the gap was formed almost uniformly over the width of the element of 100 μm.

  This is presumably because the comparative example 1 is a very low density film having a bulk density ratio of less than 0.7. That is, a film formed in a high pressure region where the pressure during sputtering is 1.4 Pa forms a so-called columnar structure film in which the continuity of the film is higher in the vertical direction than in the normal direction. In Comparative Example 1, since the bulk density ratio is as low as less than 0.7, it is presumed that the mechanical strength difference between the vertical direction and the parallel direction is small, and it is difficult to form a uniform gap.

  On the other hand, in Examples 1 to 4, since the bulk density ratio is 0.7 to 1.0, the difference in mechanical strength between the film in the vertical direction and the parallel direction on the substrate derived from the columnar structure is increased. It is inferred that uniform gaps were formed.

In Comparative Example 2, the bulk density ratio is as high as 0.95, but even when the voltage is increased to 50 V, the resistance does not reach 1.0 × 10 ⁷ Ω / □ or more, and there is a gap in the electron emission portion forming film. Could not be formed. This is because the metal content is as high as 25 atom%, and a conductive path is formed between the palladium particles during forming, so that the current does not flow so much into the carbon film having a higher specific resistance than palladium, and the input power is almost the same. This is probably because it was not used for cutting.

  In Examples 1 to 4 and Comparative Example 1, the film having a lower sheet resistance tended to finish forming at a lower voltage.

(Example 5)
An electron-emitting device was obtained in the same manner except that the pressure in the chamber during sputtering in Example 1 was changed to 2.0 Pa and the sputtering time was changed to 3 minutes.

(Example 6)
An electron-emitting device was obtained in the same manner except that the pressure in the chamber during sputtering in Example 1 was changed to 0.8 Pa and the sputtering time was changed to 2 minutes.

  As a result of observing the electron emission portion forming films of the elements of Examples 5 and 6 with a transmission electron microscope from the cross-sectional direction, it was confirmed that all the metal fine particles were present in the form of fine particles having a diameter of 1 to 5 nm in the carbon film. It was.

  The gap formed in the electron emission portion forming film after forming in Example 1 and Examples 5 to 6 was observed with a scanning electron microscope, and the width of the gap was measured.

  The values obtained in Example 1 and Examples 5 to 6 are shown in Table 2.

  As can be seen from Table 1, in Examples 1 to 4 and Comparative Example 1, the film having a lower sheet resistance tended to finish forming at a lower voltage. However, as shown in Table 2, Examples 1 and 5 From No. to No. 6, the film having a higher sheet resistance tended to finish forming at a lower voltage.

  In Example 1 and Examples 5 to 6, the sheet resistance increases as the pressure during sputtering increases. When the sputtering pressure is increased, a so-called columnar structure in which the continuity of the film is higher in the direction perpendicular to the substrate than in the direction parallel to the substrate becomes more prominent. For this reason, the sheet resistance value correlating with the continuity in the direction parallel to the substrate is increased, and it is considered that the gap is formed with lower energy as the structural anisotropy increases. Therefore, Example 5 forms a gap at a low voltage with a higher resistance electron emission portion forming film, and can be said to be a more preferable embodiment of the present invention from the viewpoint of reducing forming power.

  Further, in Example 1 and Example 5, the gap was uniformly formed with a width of about 10 nm across the width of the element of 100 μm, but in Example 6, a wide part with a gap width of about 40 nm was observed in some places. Also from this fact, it is a preferred embodiment of the present invention that the pressure during sputtering is 1.0 Pa or more, and more preferably 2.0 Pa or more.

(Example 7)
An electron-emitting device was obtained in the same manner except that the sputtering time in Example 1 was changed to 6 minutes and 40 seconds.

  As a result of observing the obtained electron emission portion forming film with a transmission electron microscope from the cross-sectional direction, it was confirmed that metal fine particles were present in the form of fine particles having a diameter of 1 to 5 nm.

In Example 1 and Example 7, the state of carbon before and after forming was analyzed using a microscopic laser Raman spectrophotometer. The obtained Raman spectrum was spectrally separated into a so-called G band having a peak in the vicinity of 1580 cm ⁻¹ derived from the SP2 bonding property of carbon and a so-called D band having a peak in the vicinity of 1360 cm ⁻¹ derived from the SP3 bonding property. Then, the change rate before and after the energization forming of the half width for each of the G band and the D band was calculated.

  In Example 1, the change rate of the half width before and after energization forming is 80% or more and 120% or less in both G band and D band. In Example 7, the change in half width is both in G band and D band. The rate is 60% or less. It can be inferred that during the forming process, the carbon binding property in Example 1 did not change relatively, whereas in Example 7, the carbon was greatly modified to become carbon with higher crystallinity. Is done. Along with this, in Example 7, the resistance is greatly reduced during forming, and both the forming end voltage and the maximum current during forming are increased. Therefore, it can be seen that Example 1 is formed with lower power than Example 7, and is a more preferable embodiment of the present invention from the viewpoint of reduction of environmental load and manufacturing cost.

(Example 8)
In the electron-emitting device obtained in Example 2, activation treatment was performed following energization forming. Specifically, tolunitrile vapor was introduced into the chamber at a partial pressure of 1.3 × 10 ⁻⁴ Pa, a pulse voltage was applied between the electrodes 3a and 3b, and activation was performed for 30 minutes. The pulse waveform is the waveform of FIG. 3A, and a rectangular pulse of 18 V and T1 = 1 ms and a rectangular pulse of -18 V and T1 = 1 ms were alternately applied at 100 Hz. The amount of electron emission during the activation process and its variation over time were observed.

Example 9
An electron-emitting device was obtained and evaluated in the same manner except that the sputtering time in Example 8 was changed to 75 seconds.

  As a result of observing the electron emission portion forming film of the obtained electron-emitting device with a transmission electron microscope from the cross-sectional direction before the energization forming, metal fine particles exist in the form of fine particles having a diameter of 1 to 5 nm in the carbon film. It was confirmed.

In Example 1 and Example 8, the state of carbon before and after energization forming was analyzed using a microscopic laser Raman spectrophotometer. The obtained Raman spectrum was spectrally separated into a so-called G band having a peak in the vicinity of 1580 cm ⁻¹ derived from the SP2 bonding property of carbon and a so-called D band having a peak in the vicinity of 1360 cm ⁻¹ derived from the SP3 bonding property. Then, the change rate before and after the energization forming of the half width for each of the G band and the D band was calculated.

  In Example 9, the change rate of the half width before and after energization forming is 80% or more and 120% or less in both G band and D band, but in Example 8, the change in half width is both in G band and D band. The rate was 60% or less. It can be inferred that, during the forming process, the carbon bonding property in Example 9 did not change relatively, whereas in Example 8, the carbon was greatly modified to become carbon with higher crystallinity. Is done.

  In correlation with this, Example 8 had a larger amount of electron emission during activation than Example 9, and the amount of electron emission was more stable. This is because in Example 8, the crystallinity related to the SP2 bond is higher at the time of forming, and there are more π electrons that are more difficult to be bound to the nuclei, so the amount of emitted electrons may be larger. Seem. In addition, it is considered that the crystallinity becomes high during forming, so that the thermal stability at the time of activation becomes high, and the fluctuation of the electron emission amount is also reduced.

  Therefore, it can be seen that Example 9 is a more preferred embodiment of the present invention from the viewpoint of electron source characteristics.

(Example 10)
An electron source having a plurality of electron-emitting devices of Example 1 was produced. The manufacturing process will be described with reference to FIGS.

  Electrodes 3a and 3b made of Pt having a thickness of 40 nm were formed on the glass substrate 21 by a sputtering method and a lift-off method (FIG. 10). Next, paste material (NP-4035C manufactured by Noritake Co., Ltd.) was printed on the substrate using a screen printing technique, and baked at 450 ° C. to form a Y-direction wiring 23 having a thickness of 10 μm ( FIG. 11). The Y-direction wiring 23 is connected to the electrode 3b. Next, a paste material (NP-7710 manufactured by Noritake Co., Ltd.) was printed on the substrate using a screen printing technique, and baked at 570 ° C. to form an insulating film 61 having a thickness of 20 μm (FIG. 12). Next, paste material (NP-4035C manufactured by Noritake Co., Ltd.) was printed on the substrate using a screen printing technique, and baked at 450 ° C. to form an X-direction wiring 22 having a thickness of 10 μm ( FIG. 13). The X-direction wiring 22 is connected to the electrode 3a. Further, the X direction wiring 22 and the Y direction wiring 23 are insulated by the insulating film 61.

  The substrate 21 on which the electrodes 3a and 3b and the wirings 22 and 23 were formed was washed. Thereafter, a photosensitive resin (methacrylic acid-methyl methacrylate-ethyl acrylate-n-butyl acrylate-azobisisobutyronitrile polymer) was applied to the entire surface with a slit coater and dried at 100 ° C. for 10 minutes.

  Subsequently, the area | region which forms the pattern of the coating film of the photosensitive resin using a photomask was exposed, and it developed for 60 second by the pure water shower, and obtained the resin pattern.

The substrate 21 on which the resin pattern was formed was put into an RF magnetron sputtering apparatus and evacuated until the pressure in the chamber became 5 × 10 ⁻⁵ Pa or less. As the sputtering target, a composite target in which metal palladium particles were dispersed in amorphous carbon was used.

  After reaching a predetermined pressure, an argon gas was introduced into the chamber so that the pressure became 1.4 Pa, and the sputtering time and input power were adjusted so that the film thickness became 11 nm.

  Next, the substrate 21 was taken out from the RF magnetron sputtering apparatus, treated with an aqueous tetramethylammonium hydride solution (concentration: 2.38 mass%) for 5 minutes, and the resist was peeled off to form the electron emission portion forming film 4 (FIG. 14). ).

The substrate 21 thus formed was held in a vacuum chamber. The X-direction wiring 22 and the Y-direction wiring 23 are connected to the probe group in the chamber, respectively, so that energization processing and resistance measurement can be performed from outside the chamber. The chamber is evacuated by a turbo molecular pump and a scroll pump until the pressure inside the chamber reaches 1 × 10 ⁻⁶ Pa or less, and a minute gap is formed in the electron emission portion forming film 4 by the following energization forming process. Went.

  For each X-direction wiring, the triangular wave in FIG. 2B is a rectangular wave, and a pulse voltage of T1 = 0.1 ms and T2 = 50 ms is applied. The voltage started from 1V, increased by 0.1V every 5 seconds, applied to 30V, and then the voltage application was terminated. In the process of increasing the voltage, when about 20 to 25 V is applied, a gap is formed in the electron emission portion formation film 4 due to the influence of Joule heat by energization, and at the end of voltage application, the electron emission portion formation film 4 of all lines is formed. The resistance value increased to 1 MΩ or more. Thus, the gap 5 was formed in the central portion of the electron emission portion forming film 4.

Subsequently, tolunitrile vapor was introduced into the chamber at a partial pressure of 1.3 × 10 ⁻⁴ Pa, a pulse voltage was applied between the X direction wiring 22 and the Y direction wiring 23, and activation was performed for 30 minutes. The pulse has a waveform shown in FIG. 3A, and an 18 V, 1 ms rectangular pulse and a -18 V, 1 ms rectangular pulse were alternately applied at 100 Hz. Observation of the increase in device current during the activation process revealed a uniform increase in current over the entire conductive film.

  As described above, an electron source substrate having uniform electron emission efficiency of individual electron-emitting devices can be formed on the substrate.

  Further, an image display device as shown in FIG. 7 was manufactured using this electron source substrate. The electron source substrate 21 was placed in a rear plate 31, a support frame 36, and a face plate 36 made of a glass material, and each member was bonded. For the bonding, frit glass was used, and heating was performed at 450 ° C. for bonding. A metal back 35 and a phosphor 34 are formed inside the face plate 36, and a high voltage terminal Hv connected to the metal back 35 is drawn out of the image display apparatus. Further, the air inside was exhausted through an exhaust pipe (not shown) using a vacuum pump. The exhaust pipe was welded with a gas burner to complete the image display device. An image was displayed by applying a potential of 4 kV to the metal back 35 of the image display device through the high voltage terminal Hv and inputting an image signal to the X-direction wiring 22 and the Y-direction wiring 23.

  It was observed that a uniform display without unevenness was obtained over the entire display screen.

It is the figure which showed typically preferable embodiment of the electron-emitting element of this invention. It is a figure which shows the example of the voltage waveform used for the energization forming which concerns on this invention. It is a figure which shows the example of the voltage waveform used by the activation process which concerns on this invention. It is the schematic of the measurement evaluation apparatus for measuring the characteristic of the electron-emitting element of this invention. It is a figure which shows the characteristic of the electron-emitting element of this invention. It is a figure which shows the structural example of the electron source which uses the electron-emitting element of this invention. It is a figure which shows the structural example of the display panel of the image display apparatus of this invention. It is a figure which shows the structural example of the fluorescent film used for the image display apparatus of this invention. It is a figure which shows the example which used the image display apparatus of this invention for the television display. It is a figure which shows the manufacturing process of the electron source of the Example of this invention. It is a figure which shows the manufacturing process of the electron source of the Example of this invention. It is a figure which shows the manufacturing process of the electron source of the Example of this invention. It is a figure which shows the manufacturing process of the electron source of the Example of this invention. It is a figure which shows the manufacturing process of the electron source of the Example of this invention. It is a figure which shows the manufacturing process of the electron source of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Electrode part 3a, 3b Electrode 4 Electron emission part formation film 5 Gap

Claims (10)

An electrode part having a pair of electrodes and an electron emission part forming film sandwiched between the electrodes is formed on the substrate, and a gap is formed in the electron emission part forming film by applying a current treatment between the electrodes. An electron-emitting device,
The electron emission portion forming film is a mixed film made of metal and carbon, the metal content is 1 to 20 atom%, and the metal is in the form of fine particles having a diameter of 1 to 5 nm, An electron-emitting device having a density ratio with respect to a bulk of 0.7 to 1.0.   2. The electron emission according to claim 1, wherein the metal contained in the electron emission portion forming film is one or more selected from the group consisting of Ni, Co, Pd, Pt, Ir, and Rh. element.   3. The electron-emitting device according to claim 1, wherein a film thickness of the electron-emitting portion forming film is 5 nm or more and 50 nm or less. An electrode part having a pair of electrodes and an electron emission part forming film sandwiched between the electrodes is formed on the substrate, and a gap is formed in the electron emission part forming film by applying a current treatment between the electrodes. A method for manufacturing an electron-emitting device, comprising:
The electron emission portion forming film is a mixed film made of metal and carbon, the metal content is 1 to 20 atom%, and the metal is in the form of fine particles having a diameter of 1 to 5 nm, A method for manufacturing an electron-emitting device, wherein a density ratio to a bulk is 0.7 or more and 1.0 or less.   5. The electron emission according to claim 4, wherein the metal contained in the electron emission portion forming film is one or more selected from the group consisting of Ni, Co, Pd, Pt, Ir, and Rh. Device manufacturing method.   6. The method of manufacturing an electron-emitting device according to claim 4, wherein the film thickness of the electron-emitting portion forming film is 5 nm or more and 50 nm or less.   7. The method of manufacturing an electron-emitting device according to claim 4, wherein the electron-emitting portion forming film is formed by a sputtering method, and the pressure in the chamber during sputtering is 1.0 Pa or more. .   In energization processing for forming a gap in the electron emission portion forming film, the rate of change before and after the energization processing of at least one half width of carbon G band and D band in visible light Raman spectroscopy of the electron emission portion formation film The method of manufacturing an electron-emitting device according to claim 4, wherein the energization process is performed so that the ratio is 80% to 120%.   In energization processing for forming a gap in the electron emission portion forming film, the half width after energization processing of at least one of carbon G band and D band in visible light Raman spectroscopy of the electron emission portion formation film is energization processing. The method for manufacturing an electron-emitting device according to claim 4, wherein an energization process is performed so that the amount is less than the previous 80%.   An electron source comprising a plurality of electron-emitting devices according to any one of claims 1 to 3 and a plurality of wirings for applying a voltage to the electron-emitting devices, and emitting from the electron-emitting devices of the electron source And a counter substrate provided with a light emitting member that emits light when irradiated with emitted electrons.

Images