JP2008257985A - Image display device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life image display device capable of improving electron emission performance of an electron source formed in a display region that does not have display unevenness. <P>SOLUTION: In forming a tunnel insulating film, a positive electrode and a negative electrode of a power source E are connected to a lower electrode 11 and a platinum electrode 22, respectively. In its anodic oxidation process, a tunnel insulation layer 12 (alumina Al<SB>2</SB>O<SB>3</SB>) is formed on the lower electrode 11. During this reaction, PO<SP>3-</SP>ions dissolved in a chemical conversion solution 23 are captured in the tunnel insulation film 12. The tunnel insulation film 12 comprises a surface layer 12A that is an anion layer developing toward the chemical conversion solution 23 from an original surface of an aluminum film constituting the lower electrode 11, and a lower layer 12B growing toward the original aluminum film. The surface layer 12A is ion-conductive. The PO<SP>3-</SP>ions are taken in the surface layer 12A, and thereafter, is subjected to a reverse bias process by changing over the polarity of the power source E. The reverse-bias processing is only for a short period. By this processing, K<SP>+</SP>ions in an electrolytic solution adhere to a surface of the surface layer 12A. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image display device, and more particularly to an image display device also called a self-luminous flat panel display in which thin-film electron-emitting devices are arranged in a matrix, and a method for manufacturing the same.

  2. Description of the Related Art A flat image display device (flat panel display: FPD) has been developed in which electron-emitting devices (electron sources, cathodes), which are also referred to as thin film type electron sources that can be integrated, are arranged in a matrix. The electron source of this type of image display apparatus is classified into an electron emission type electron source and a hot electron type electron source. The former includes spindt type electron sources, surface conduction type electron sources, carbon nanotube type electron sources and the like, and the latter includes metal-insulator-metal stacked MIM (metal-insulator-metal) type, metal-insulators. There are thin-film electron sources such as MIS (Metal-Insulator-Semiconductor) type, metal-insulator-semiconductor-metal type, etc. in which semiconductors are stacked.

  Regarding the MIM type, for example, in Patent Document 1, the metal-insulator-semiconductor type is the MOS type (Non-Patent Document 1), the metal-insulator-semiconductor-metal type is the HEED type (described in Non-Patent Document 2, etc.), An EL type (described in Non-Patent Document 3 and the like), a porous silicon type (described in Non-Patent Document 4 and the like), and the like have been reported.

  The MIM type electron source is also disclosed in Patent Document 2, for example. The structure and operation of the MIM type electron source are as follows. That is, it has a structure in which an insulating layer (tunnel insulating layer) is interposed between the upper electrode and the lower electrode, and a Fermi level in the lower electrode is obtained by applying a voltage between the upper electrode and the lower electrode. Nearby electrons pass through the barrier due to the tunnel phenomenon, and are injected into the conduction band of the tunnel insulating layer, which is the electron acceleration layer, to become hot electrons, and flow into the conduction band of the upper electrode. Among these hot electrons, those that reach the surface of the upper electrode with energy equal to or higher than the work function φ of the upper electrode are released into the vacuum. Hereinafter, the thin film type electron-emitting device is also simply referred to as an electron source.

  FIG. 19 is a perspective view of an essential part of an MIM type electron source for explaining an example of the structure of a thin film type electron-emitting device. FIG. 20 is a schematic cross-sectional view cut in the A-A ′ direction of FIG. 19. In FIG. 19, the upper electrode 13 shown in FIG. 20 is omitted. 19 and 20, a lower electrode 11 made of aluminum (Al) or aluminum-neodymium alloy (Al-Nd) is formed on the main surface (inner surface) of an insulating substrate 10 (also referred to as a cathode substrate) preferably made of glass. Yes. On the upper surface of the lower electrode 11, a chemically formed tunnel insulating film 12 and a field insulating film 14 filling the periphery of the tunnel insulating film 12 are formed. A region of the tunnel insulating film 12 is an electron emission portion of a unit pixel, and an upper electrode 13 is formed so as to cover the tunnel insulating film 12 and the field insulating film 14.

In FIG. 19, a scanning line 21 is formed in the vicinity of the electron emission portion via an insulating film 15 preferably made of silicon nitride. In this example, the scanning line 21 has a scanning line bus electrode 16 preferably made of aluminum and a cap 17 made of chromium or the like thereon, and further has a contact electrode 18 made of chromium or the like below the scanning line bus electrode 16. It has a three-layer structure.
JP-A-7-65710 Japanese Patent Laid-Open No. 10-153979 j.Vac.Sci.Technol.B11 (2) p.429-432 (1993) high-efficiency-electro-emission device, Jpn, j, Appl, Phys, vol. 36, pp. 939 Electroluminescence, Applied Physics Vol. 63, No. 6, p. 592 Applied Physics Vol. 66, No. 5, p. 437

  In an image display device using this type of electron-emitting device, a plurality of the electron-emitting devices are arranged on a flat insulating substrate (cathode substrate) in a two-dimensional matrix (also called an array) to form a display region. However, the tunnel insulating film (electron acceleration layer) constituting the electron-emitting device is an amorphous oxide film obtained by anodizing the lower electrode. The lower electrode is composed of a metal film made of a single layer of an aluminum film or an aluminum alloy film (such as an aluminum-neodymium alloy film), or a metal laminated film having an uppermost layer made of an aluminum film or an aluminum alloy film. The process of forming a tunnel insulating film by chemical conversion treatment (anodic oxidation) of the lower electrode is performed by immersing the insulating substrate on which the metal film is formed in a chemical conversion solution (electrolytic solution), and one edge of the metal film on the edge of the metal film. An anodic oxidation step (an anodizing treatment step) is performed in which an electrode (anode) is connected and an electric current (formation current) is passed between the other electrode (cathode suitable for platinum Pt) installed in the electrolytic solution.

  A thin upper electrode is formed on the tunnel insulating film thus formed to form an MIM type electron source. The lower electrode is connected to the data signal driving circuit, and the upper electrode is connected to the scanning signal driving circuit. In this type of electron source, an iridium-platinum-gold film having a thickness of about 2 nm, which is formed to cover the tunnel insulating film having a thickness of about 10 nm formed on the surface of the lower electrode, is preferably used. Released. The amount of electrons emitted is limited by the work function of the tunnel insulating film, and the smaller this work function, the more emitted electrons (emissions).

Electron emission efficiency can be improved by attaching K ⁺ ions to the tunnel insulating film constituting the electron source. The conventional method for attaching K ⁺ ions to the tunnel insulating film is as follows. First, after forming a tunnel insulating film by anodic oxidation (anodization) treatment, it is immersed in a 0.05% wt aqueous solution of K ₂ HPO ₄ powder for 3 minutes. This is air knife dried. By performing this treatment, K ⁺ ions adhere to the tunnel insulating film. Electron emission is improved by attaching K ⁺ ions to the tunnel insulating film. Further, P ⁺ ions or Cs ⁺ ions improve the film quality and contribute to extending the lifetime of the electron source.

However, in the above conventional K ⁺ ion deposition treatment, it is necessary to add a process of immersing in a K ₂ HPO ₄ aqueous solution after the tunnel insulating film is formed and drying it with an air knife to the anodizing treatment process. Further, the K ⁺ ion adhesion unevenness occurs between the electron sources due to the immersion state in the K ₂ HPO ₄ aqueous solution and the air knife dry state, resulting in the in-plane unevenness of the electron emission. Similarly, uneven concentration of P ⁺ ions (PO ₄ ) or Cs ⁺ ions doped in the tunnel insulating film occurs. As a result, it has been difficult to obtain a high-quality image display device.

  The first object of the present invention is to reduce the difference in the electron emission performance of the electron sources formed in the display area formed on the insulating substrate so that there is no display unevenness, and the film quality is improved to extend the life. It is to provide a display device. A second object of the present invention is to provide a manufacturing method thereof.

In order to achieve the first object, in the present invention, a plurality of upper electrodes formed on a lower electrode formed on a flat insulating substrate (cathode substrate) via a tunnel insulating film are formed. In the image display device in which the electron-emitting devices are arranged in a matrix, the tunnel insulating film constituting the electron-emitting device is an amorphous oxide film formed by anodizing the surface of the lower electrode, and the tunnel insulation The film was doped with PO ³⁻ ions, and K ⁺ ions were deposited on the surface of the tunnel insulating film.

In order to achieve the second object, in the manufacturing method of the present invention, the lower electrode constituting the electron-emitting device formed on the flat insulating substrate is mixed with an aqueous solution containing PO ^3- ions and K ⁺ ions. In the chemical conversion step of immersing in the formed chemical solution and forming an oxide film on the surface of the lower electrode as an anode, the surface layer of the anodic oxide film is doped with PO ^3- ions, and after the chemical conversion step, A bias voltage opposite to that in the chemical conversion step is applied to the lower electrode to attach K ⁺ ions to the surface of the surface layer of the anodic oxide film.

  The present invention is not limited to the technical scope described in the claims summarized in the above configuration and the examples described in the embodiments described later, and various modifications can be made without departing from the technical idea of the present invention. Needless to say, it is possible to make changes.

  According to the image display device of the present invention, the difference in the electron emission performance of the electron source is reduced, there is no display unevenness, the film quality is improved, and a long-life image display device is obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings of the examples. In the following, an embodiment of the present invention will be described by taking an image display device using an MIM (metal-insulator-metal) type electron source as an example, but an image display device using another electron source using an anodic oxide film will be described. The same applies to.

  FIG. 1 is a diagram illustrating a configuration example of an electron source according to the first embodiment of the image display apparatus according to the present invention. FIG. 1 shows the MIM type electron source described above, FIG. 1A shows a plane of the electron source, and FIG. 1B shows a cross section of FIG. This electron source has a lower electrode 11 serving as a data signal line on the main surface of the glass substrate 10. The lower electrode 11 is made of an aluminum-neodymium alloy, but may be made of aluminum alone or may have a laminated structure of two or more layers of these alloys or single metals. An anodized (chemical conversion) tunnel insulating film 12 is formed on the electron emission portion of the surface of the lower electrode 11, and an anodized field insulating film 14 is formed around the tunnel insulating film 12. The tunnel insulating film 12 and the field insulating film 14 have different conditions for chemical conversion treatment.

  Around the tunnel insulating film 12, an insulating film (interlayer insulating film) 15 that is preferably a silicon nitride film is provided on the field insulating film 14, and a scanning line 21 is formed thereon. The scanning line 21 has a laminated structure of the lower metal film 18, the middle metal film 16 and the upper metal film 17. In this configuration, the lower metal film 18 is chromium (Cr), and is a contact electrode that is connected to an upper electrode described later. The intermediate metal film 16 is made of aluminum, and is a scanning line bus electrode that proposes a wiring resistance of an operation signal. The upper metal film 17 is a chromium cap electrode. The scanning line 21 is not limited to such a configuration, and the lower metal film 18 and the upper metal film 17 are made of an aluminum-neodymium alloy, or a silicon film is used instead of the lower metal film 18.

  An upper electrode 13 made of a three-layer CVD film of iridium (Ir), platinum (Pt) and gold (Au) is formed so as to cover the scanning line 21, the tunnel insulating film 12 and the field insulating film 14. As shown on the right side of FIG. 1B, the upper electrode 13 is in reliable contact with the scanning line 21 by a taper (inclined portion) 20 of the lower layer metal film 18 of the scanning line 21. Further, as shown on the left side of FIG. 1B, the adjacent unit pixels are separated in a self-aligned manner by the middle layer metal film 16 formed by etching back the lower layer metal film 18. Yes.

FIG. 2 is a schematic diagram for explaining a reaction system in the anodizing process for forming the tunnel insulating film of FIG. FIG. 3 is an explanatory diagram showing the reaction system shown in FIG. 2 divided into the incorporation of PO ³⁻ ions and the attachment of K ⁺ ions. The lower electrode 11 is aluminum (Al), and is immersed in an electrolytic solution (chemical conversion solution) 23 in the chemical conversion treatment tank to form one electrode, to which the anode (+) of the power source E is connected. The chemical conversion treatment tank is provided with an electrode 22 of platinum (Pt) as the other electrode, to which the cathode (-) of the power source E is connected. The chemical conversion solution 23 contains an aqueous solution of PO ³⁻ ions and K ⁺ ions.

In FIG. 3A, the power source E is connected to the first power source E1 side by the changeover switch S. The anode of the first power supply E1 is connected to the lower electrode 11 formed on the substrate, and the cathode is connected to the platinum electrode 22. In this anodizing process, when the voltage of the power source E1 is 6 V, an insulating layer (tunnel insulating layer) 12 having a thickness of about 10 nm is formed on the lower electrode 11. The tunnel insulating layer 12 is alumina (Al ₂ O ₃ ), and PO ³⁻ ions dissolved in the chemical conversion liquid 23 are taken into the tunnel insulating layer 12 during the reaction. The tunnel insulating layer 12 includes a surface layer 12A that is an anion layer that grows from the original surface of the aluminum film that forms the lower electrode 11 toward the chemical conversion solution 23, and a lower layer 12B that grows toward the original aluminum film. The surface layer 12A is ion conductive. PO ³⁻ ions are taken into the surface layer 12A.

Thereafter, the power source E is connected to the second power source E2 side by the changeover switch S. The anode of the second power source E2 is connected to the platinum electrode 22 and the cathode is connected to the lower electrode 11 and subjected to reverse bias processing. This reverse bias processing is a short time (about 10 minutes). By this treatment, K ⁺ ions in the electrolytic solution adhere to the surface of the surface layer 12A in FIG.

According to this embodiment, the amount of electron emission of the electron source is increased by the action of K ⁺ ions attached to the surface of the tunnel insulating film, the difference in electron emission performance of the electron source is reduced, and display unevenness is eliminated. In addition, the film quality is improved by the action of PO ³⁻ ions or Cs ⁺ ions incorporated into the tunnel insulating film, and a long-life image display device can be obtained. The improvement in film quality by PO ³⁻ ions or Cs ⁺ ions is considered to be due to the reduction of work function for electron emission.

  A method for manufacturing an image display device according to the present invention will be described below as a second embodiment with reference to FIGS. 4 to 17 are a plan view for explaining a manufacturing process of a thin film electron source constituting the cathode substrate of the image display device of the present invention and a cross-sectional view of a main part thereof. First, as shown in FIG. 4, a metal film for the lower electrode 11 is formed on an insulating substrate 10 such as glass. An aluminum (Al) alloy is used as the material of the lower electrode 11. The reason why the Al alloy is used is that a high-quality insulating film can be formed by the anodic oxidation described above. Here, an aluminum-neodymium alloy (Al-Nd) doped with 2 atomic% of neodymium (Nd) was used. For this film formation, for example, a sputtering method is used. The film thickness was 600 nm.

  After the metal film for the lower electrode 11 is formed, the stripe-shaped lower electrode 11 is formed by a patterning process and an etching process (FIG. 5). The electrode width of the lower electrode 11 varies depending on the size and resolution of the image display device, but is approximately the pitch of the subpixel, approximately 100 to 200 microns (μm). For the etching, for example, wet etching using a mixed aqueous solution of phosphoric acid, acetic acid, and nitric acid is used. It is desirable that the side edge of the lower electrode 11 is positively tapered. Since the lower electrode 11 has a wide and simple stripe structure, the resist patterning can be performed by inexpensive proximity exposure or a printing method.

  Next, a field insulating film (also referred to as a protective insulating layer) 14 and a tunnel insulating film 12 that limit the electron emission portion and prevent electric field concentration on the edge of the lower electrode 11 are formed. First, a portion to be an electron emission portion on the lower electrode 11 shown in FIG. 6 is masked with the resist film 25, and the other portions are selectively thickly anodized to form the field insulating film. For example, the field insulating film 14 having a thickness of about 270 nm is formed at a formation voltage of 200V. Thereafter, the resist film 25 is removed and the surface of the remaining lower electrode 11 is anodized. For example, a tunnel insulating layer 12 having a thickness of about 10 nm is formed on the lower electrode 11 with a formation voltage of 6 V (FIG. 7).

  Next, silicon nitride is sputtered to form an insulating film 15 (FIG. 8). Note that the insulating film 15 in the seal portion on the outer periphery of the display region that reacts with the frit glass is removed by dry etching. Then, the insulating film 15 in the scanning line forming portion is removed by dry etching to expose the field insulating film 14 (FIG. 9). Here, anodization is again performed in the chemical conversion tank, and damage repair of the field insulating film 14 at the scanning line forming portion is performed (FIG. 10). This re-oxidation process is performed to prevent the field insulating film 14 from being peeled off, and is a process that is not necessarily required when the previous field insulating film 14 is not peeled off.

  Next, chromium, aluminum, and chromium are sequentially formed so as to cover the entire surface of the substrate, and a three-layer metal film including a lower layer metal film 18 serving as a contact electrode, a scanning line bus electrode 16, and a cap electrode 17 is formed ( FIG. 11). Thereafter, a resist mask is formed by a photolithography process of resist application, pattern exposure, and development, and etching is performed using this resist mask. First, the cap electrode 17 is patterned with an etching solution that dissolves chromium (FIG. 12). . Next, the scanning line bus electrode 16 is patterned with an etching solution for dissolving aluminum (FIG. 13). Then, the lower metal film 18 is patterned with an etching solution that dissolves chromium (FIG. 14).

Next, the insulating film (SiN) covering the tunnel insulating film 12 is removed by dry etching using SF ₆ + O ₂ + He mixed gas to expose the tunnel insulating film 12 (FIG. 15). At this time, the adjacent pixel side of the lower layer metal film 18 to be a contact electrode is etched back to form a ridge structure in the scanning line bus electrode 16, and a taper 20 is formed at the edge on the tunnel insulating film 12 side. Here, the tunnel insulating film 12 is again put into the chemical conversion tank, and the tunnel insulating film 12 is anodized (FIG. 16). This reanodization is also a process for repairing damage to the tunnel insulating film 12.

  Finally, iridium, platinum, and gold are sequentially formed on the entire surface of the substrate by sputtering to form the upper electrode 13 (FIG. 17). During the sputtering film formation, as described with reference to FIG. 1, the upper electrode 13 is separated in a self-aligned manner from the adjacent pixels by the saddle structure of the scanning line bus wiring 16 of the scanning line 21.

  FIG. 18 is a schematic plan view for explaining the image display device according to the present invention as an example of a display device using an MIM type electron source. In FIG. 1, the plane of a substrate (cathode substrate) 10 having an electron source is shown, and the other substrate (phosphor substrate, anode substrate) on which a phosphor and an anode are formed is not shown.

  The substrate 10 includes a lower electrode 11 and an upper electrode 13 constituting a signal line (data line) connected to the signal line driving circuit 50, a scanning line 21 connected to the scanning line driving circuit 60 and orthogonal to the signal line, A lower metal film 18 which is a contact electrode for connecting the upper electrode 13 at a part of the scanning electrode, a ridge structure 19 for separating the upper electrode 13 for each scanning line, and the like are formed. The electron source array (electron emission portion) is formed by the upper electrode 13 that is disposed between the scanning lines 21 where the intersection is located on the lower electrode 11 and is stacked on the lower electrode 11 via the tunnel insulating film 12. The As described, electrons are emitted from the portion of the tunnel insulating layer 12 formed by the thin layer portion surrounded by the thick field insulating layer 14 that limits the region of the electron emission portion.

In addition, on the inner surface of the phosphor screen substrate (not shown), a light shielding layer for increasing the contrast of a display image, that is, a black matrix, a red phosphor, a group of phosphors of a plurality of colors, typically a green phosphor and a blue phosphor, are arranged. A phosphor screen and an anode that accelerates electrons emitted from the electron source of the cathode substrate 10 to collide with these phosphors and are excited are formed. As the phosphor, for example, Y ₂ O ₂ S: Eu (P22-R) for red, ZnS: CuAl (P22-G) for green, and ZnS: AgCl (P22-B) for blue can be used. The cathode substrate 10 and the phosphor screen substrate are held at predetermined intervals by the spacers 30 and sealed with a sealing frame 40 interposed on the outer periphery of the display area, and then the interior is vacuum sealed. In FIG. 18, the inner end and the outer end of the sealing frame 40 are indicated by bold lines, and the range indicated by the arrow a and the interval indicated by the arrow b is the sealing frame 40. The inside indicated by the arrow b is vacuum sealed. Further, the upper electrode 13 is formed in the range indicated by the arrow c. A portion where the lower metal film 18 within the range indicated by the arrow d is etched back and separated from the adjacent pixels is shown.

  The spacer 30 is disposed on the scanning electrode 21 of the cathode substrate 10 and is disposed so as to be hidden under the black matrix of the phosphor screen substrate. The lower electrode 11 is connected to the signal line driving circuit 50, and the scanning electrode 16 that is a scanning electrode wiring is connected to the scanning line driving circuit 60. Each of the electron sources constituting one pixel (color pixel) for full-color display constitutes a unit pixel (sub-pixel for color display) corresponding to each of the phosphors.

It is a figure explaining the structural example of the electron source of Example 1 of the image display apparatus concerning this invention. It is a schematic diagram explaining the reaction system in the anodizing process which forms the tunnel insulating film of FIG. FIG. ³ is an explanatory diagram showing the reaction system shown in FIG. 2 divided into PO ³⁻ ion uptake and K ⁺ ion attachment. It is the top view explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention, and its principal part sectional drawing. FIG. 5 is a plan view subsequent to FIG. 4 for explaining the manufacturing process of the thin film electron source constituting the cathode substrate of the image display device of the present invention and a cross-sectional view of the main part thereof. It is the top view and principal part sectional drawing following FIG. 5 explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. It is the top view and principal part sectional drawing following FIG. 6 explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. FIG. 8 is a plan view subsequent to FIG. 7 for explaining the manufacturing process of the thin film electron source constituting the cathode substrate of the image display device of the present invention and a cross-sectional view of the main part thereof. FIG. 9 is a plan view subsequent to FIG. 8 for explaining the manufacturing process of the thin film electron source constituting the cathode substrate of the image display device of the present invention and a cross-sectional view of the main part thereof. It is explanatory drawing of the re-forming process which repairs the damage of the field insulating film of the scanning line formation part explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. FIG. 10 is a plan view subsequent to FIG. 9 for explaining the manufacturing process of the thin film electron source constituting the cathode substrate of the image display device of the present invention and a cross-sectional view of the main part thereof. It is the top view and main part sectional drawing following FIG. 11 explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. FIG. 13 is a plan view subsequent to FIG. 12 for explaining the manufacturing process of the thin film electron source constituting the cathode substrate of the image display device of the present invention, and a cross-sectional view of the main part thereof. It is the top view and principal part sectional drawing following FIG. 13 explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. It is the top view and principal part sectional drawing following FIG. 14 explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. It is explanatory drawing of the re-forming process which repairs the damage of a tunnel insulating film explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. It is the top view and principal part sectional drawing following FIG. 15 explaining the manufacturing process of the thin film electron source which comprises the cathode substrate of the image display apparatus of this invention. 1 is a schematic plan view illustrating an image display device according to the present invention, using a display device using an MIM type electron source as an example. It is a principal part perspective view of the MIM type | mold electron source explaining the structural example of a thin film type electron emission element. It is the schematic sectional drawing cut | disconnected in the A-A 'direction of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Cathode substrate, 11 ... Lower electrode (data line), 12 ... Tunnel insulating film, 13 ... Upper electrode, 14 ... Field insulating film, 15 ... Insulating film, 16. ..Middle layer metal film, 17... Upper layer metal film, 18... Lower layer metal film, 19... Saddle structure, 20. .. Electrolyte, 30... Spacer, 40... Sealing frame, 50... Signal line drive circuit, 60.

Claims (10)

A plurality of electron-emitting devices composed of a lower electrode formed on a flat insulating substrate and an upper electrode formed on the lower electrode through a tunnel insulating layer are arranged in a matrix,
The tunnel insulating layer constituting the electron-emitting device is an amorphous oxide film formed by anodizing the surface of the lower electrode,
An image display device, wherein the tunnel insulating layer is doped with PO ³⁻ ions, and K ⁺ ions or Cs ⁺ ions adhere to the surface of the tunnel insulating layer. In claim 1,
The tunnel insulating layer has an anion layer grown on the surface side of the lower electrode, and the PO ³⁻ ions are doped in the anion layer. In claim 2,
The image display device, wherein the K ⁺ ions are attached to the surface of the anion layer. In any one of Claims 1 thru | or 3,
The lower electrode is a single layer film of an aluminum film or an aluminum alloy film. In any one of Claims 1 thru | or 3,
The lower electrode is a laminated film having either an aluminum film or an aluminum alloy film on the outermost surface. A lower electrode constituting an electron-emitting device formed on a flat insulating substrate is formed by using an aqueous solution containing PO ³⁻ ions and K ⁺ ions, an aqueous solution containing Cs ⁺ ions and CO ₃ ²⁻ ions, or PO ^{3. -} an aqueous solution containing ions and K ⁺ ions and Cs ⁺ ion and CO ₃ ^2- ions or Cs ⁺ ions were immersed in the chemical conversion solution which is mixed, to form an oxide film on the surface of the lower electrode as an anode A step of doping PO ^3- ions into the surface layer of the anodic oxide film by a chemical conversion step;
After the chemical conversion step, a step of applying a bias voltage opposite to the chemical conversion step to the lower electrode to attach K ⁺ ions to the surface of the surface layer of the anodic oxide film;
A method for manufacturing an image display device, comprising: In claim 6,
A method for manufacturing an image display device, comprising: growing an anion layer on the surface side of the lower electrode by the chemical conversion step; and doping the PO ³⁻ ions into the anion layer to form the tunnel insulating layer. . In claim 7,
A method of manufacturing an image display device, wherein the K ⁺ ions or Cs ⁺ ions are attached to the surface of the anion layer by applying the reverse bias voltage. In any of claims 6 to 8,
A method of manufacturing an image display device, wherein a single layer film of an aluminum film or an aluminum alloy film is used for the lower electrode. In any of claims 6 to 8,
A method of manufacturing an image display device, wherein a laminated film having an aluminum film or an aluminum alloy film on the outermost surface is used for the lower electrode.

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