JPH0765697A - Electron emission source, manufacture thereof, and display - Google Patents

Abstract

PURPOSE:To avoid short circuit between cathode gates in an electron emission source in which many electron emission cathodes are arranged. CONSTITUTION:Electron emission cathodes 6 made of an electron emission material are installed on a cathode electrode 2. Gate electrodes 4 having holes 5 corresponding to the electron emission cathodes 6 are arranged through insulating layers 3. In an electron emission source 10, insulating covering layers 14 are formed on the gate electrodes 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an electron emission source having a field emission cathode and a method for manufacturing the same, and an electron emission source and a phosphor screen for emitting an electron beam from the electron emission cathode. The present invention relates to a display device that uses a phosphor screen to emit light for display.

[0002]

2. Description of the Related Art A so-called FED (field emission display) using a field emission type micro-cathode is used as a display with a low voltage excitation and a relatively high resolution.
Research and development of display devices of the type is in progress.

This FED type display device is an ultra-thin device that displays a signal by extracting electrons from a minute conical cathode manufactured by microfabrication, that is, a so-called field emission type cathode, and exciting a facing phosphor. Is the display of. FIG. 6 shows an enlarged schematic perspective view of this example.

In FIG. 6, reference numeral 1 denotes a cathode panel made of glass or the like, on which a cathode electrode 2 made of Cr or the like is patterned and formed in a stripe pattern, for example.
_A gate electrode 4 made of Mo, W, Nb or the like is patterned and formed in a stripe shape orthogonal to the cathode electrode 2 through an insulating layer 3 made of ₂ or the like. Then, a single or a plurality of fine hole portions 5 are provided at the intersection of each cathode electrode 2 and the gate electrode 4, and a cathode is formed inside each hole portion 5.

On the inside of the front panel 11 made of glass or the like, ITO (I
A phosphor 1 of each color, that is, R (red), G (green) and B (blue) through a transparent electrode 12 made of (n, Sn mixed oxide) or the like.
3 are formed in a stripe shape, for example. Then, although not shown, the respective panels 1 and 11 were hermetically sealed with a sealing material or the like via a spacer having a predetermined size between them, for example, several hundreds of μm, and kept at a predetermined vacuum degree. A display device is configured.

FIG. 7 shows a schematic enlarged perspective view of the above-mentioned cathode portion. 7, parts corresponding to those in FIG. 6 are designated by the same reference numerals, and duplicate description will be omitted. After the electrodes 2 and 4 and the insulating layer 3 are sequentially laminated by sputtering, vacuum deposition, or the like, for example, RIE (reactive ion etching) and wet etching are performed to form the holes 5. Further, by obliquely depositing vapor deposition, sputtering or the like on the cathode panel 1 while rotating the cathode panel 1, a field emission type cathode 6 of substantially conical W or Mo is formed in the hole 5. To be done.

In this case, when an electric field of 10 ⁶ to 10 ⁸ V / cm in electric field strength and several 10 to 100 V in voltage is applied between the field emission cathode 6 and the gate electrode 4,
Electrons are ejected from the tip of the cathode 6 by the field emission effect, and the phosphor is irradiated with electrons by setting the opposing transparent electrode 12 on the phosphor side to a predetermined potential of, for example, about 300 V, so that light emission display is performed.

When the field emission type cathode 6 is used as an electron emission source as described above, the cathode 6 is formed in a minute size and arranged at a pitch of several μm, so that a low voltage and hence low power consumption thin display can be obtained. The device can be obtained.

[0009]

When the field emission type cathode 6 as described above is formed in a size of about a submicron unit, as shown in FIG. If the conductive fine particles such as the metal particles 24 enter the hole 5 provided, the gate electrode 4 and the cathode 6 are short-circuited. When the cathode electrode 2 is commonly provided for a plurality of cathodes 6, the entire cathode line is short-circuited and cannot be used as a display device. In particular, when a large number of field emission cathodes 6 are formed as described above, such defects are likely to occur, which is a factor of lowering the yield.

In order to solve this, for example, Japanese Patent Laid-Open No. 1-
Japanese Patent No. 154426 proposes a configuration in which a resistance layer is provided between the field emission cathode 6 and the cathode electrode 2. By interposing the resistance layer in this way, even if the gate electrode 4 and the cathode 6 are short-circuited, the cathode 6 cannot be used, but it is possible to avoid short-circuiting between the cathode electrode 2 and the gate electrode 4 below this. It is possible to suppress a decrease in yield.

However, even in this case, when the field emission type cathode 6 and the gate electrode 4 are short-circuited, a leak may occur between the cathode 6 and the cathode electrode 2 which are connected with high resistance.

In order to prevent such a short circuit between the gate and the cathode, for example, in JP-A-4-229922, the gate electrode 4 is patterned in a grid pattern different from the insulating layer 3 to form the cathode 6 and the gate. A configuration has been proposed in which the electrodes 4 are separated from each other and covered with a resistance coating material of about 10 ² Ωcm. However, in this case, since the number of steps such as patterning of the gate electrode 4 increases,
There is a risk that productivity will be disadvantageous in practice.

The present invention avoids a short circuit between the cathode and the gate in an electron emission source formed by arranging a large number of field emission cathodes as described above, forms an electron emission source with higher yield, and uses the same. The display device can be formed with high yield.

[0014]

According to the present invention, as shown in FIG. 1 which is an enlarged cross-sectional view of an essential part of the example, a field emission type cathode 6 made of an electron emitting substance is provided on a cathode electrode 2. In an electron emission source 10 in which a gate electrode 4 having a hole 5 corresponding to the field emission type cathode 6 is arranged via an insulating layer 3, an insulating coating layer 14 is provided on the gate electrode 4. To do.

According to the present invention, in the above structure, the insulating coating layer 14 is made of one material selected from SiO ₂ , SiN _{x and} Al ₂ O ₃ .

Furthermore, the present invention has the above-mentioned constitution,
The insulating coating layer 14 is made of an insulating material having an electric resistivity of 10 ⁷ Ωcm or more.

Further, the present invention is a method of manufacturing an electron emission source provided with a field emission type cathode made of an electron emission material, and a manufacturing process diagram of an example thereof is shown in FIGS.
An insulating material is obliquely applied onto the gate electrode 4 to form an insulating coating layer 14.

Further, according to the present invention, as shown in FIG. 1 as an example, a field emission type cathode 6 made of an electron emitting substance is provided on the cathode electrode 2, and each field emission type cathode is provided via an insulating layer 3. In the display device, the gate electrode 4 having the holes 5 corresponding to 6 is arranged to have the electron emission source 10, and the phosphor screen 20 is provided so as to face the electron emission source 10. Insulating coating layer 1 on 4
4 is provided.

[0019]

As described above, according to the present invention, the insulating layer 14 having a high resistance is provided on the gate electrode 4 of the electron emission source 10 having the field emission type cathode 6. Therefore, FIG. As shown in the enlarged cross-sectional view, even if electrically conductive dust enters the hole 5 and metal particles or the like adhere to the inner corner of the hole 5 and the cathode 6, a short circuit can be prevented. The leakage between the cathode electrode and the gate electrode can be remarkably suppressed.

Further, as the material of the insulating coating layer 14, SiO
_{By using 2} or SiN _x or Al ₂ O _3, and further by using a material having a high electric resistivity of 10 ⁷ Ωcm or more as the material of the insulating coating layer 14, it is possible to surely suppress the short circuit. .

Further, by forming the above-mentioned insulating coating layer 14 from the oblique direction by vapor deposition, sputtering or the like as shown by an arrow a in FIGS. When the panel substrate to be formed is applied while being rotated, the insulating coating layer 14 can be applied so as to also cover the inner surface of the hole 5 of the gate electrode 4. Therefore, the short circuit between the gate and the cathode can be suppressed more reliably.

Further, by constructing a display device using such an electron emission source, it is possible to significantly suppress short-circuiting of a large number of cathodes. Therefore, the yield of the display device is significantly improved. The reliability can be improved.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings. In this example, the present invention is applied to the FED type display device described in FIG.

As shown in FIG. 1, a cathode electrode 2 made of Cr or the like is patterned and formed on a cathode panel 1 made of glass or the like in a stripe shape extending in the left-right direction on the paper surface of FIG. 1, for example, SiO ₂ or the like. A gate electrode 4 made of Mo, W, Nb or the like through an insulating layer 3 made of
Are patterned in a stripe shape orthogonal to the cathode electrode 2, that is, in this case, for example, as a pattern extending in a direction orthogonal to the paper surface of FIG.

[0025] and in particular the present invention, on the gate electrode 4, SiO ₂ so as to cover the, SiN _X or Al ₂ O ₃ insulating coating layer for example made of SiO _2, such as 1
4 is attached.

FIG. 1 shows a cross section of the intersection of the cathode electrode 2 and the gate electrode 4 which are orthogonal to each other. At this intersection, a single or a plurality of fine hole portions 5 are formed in the illustrated example.
Is provided, and each of the holes 5 has a substantially conical W, Mo shape.
A field emission type cathode 6 made of, for example, is formed and configured.

On the other hand, inside the front panel 11 made of glass or the like, ITO (I
Phosphors 13 of respective colors, that is, red, blue, and green are formed in a stripe shape, for example, through a transparent electrode 12 made of a mixed oxide of n and Sn). In the example of FIG. 1, one phosphor 13 is shown. Although not shown, each panel 1, 11
Is hermetically sealed with a sealing material or the like via a spacer having a predetermined size, for example, about several hundreds of μm between them, thereby forming a thin display device held at a predetermined vacuum degree.

In this case, when a strong electric field of about 10 ⁶ to 10 ⁸ V / cm in electric field strength and several 10 to 100 V in voltage is applied between the field emission cathode 6 and the gate electrode 4, the tip of the cathode 6 is applied. Electrons fly out of the area due to the field emission effect. At this time, the transparent electrode 12 on the phosphor side facing each other
Is set to a predetermined potential of, for example, about 300 V, electrons are accelerated and incident on the phosphor screen, and light emission display can be performed by electron beam excitation.

In particular, in this embodiment, since the insulating coating layer 14 is provided so as to cover the gate electrode 4 as described above, for example, as shown in the schematic enlarged sectional view of FIG. Even when conductive fine particles such as the above enter the inside of the hole 5, it is possible to prevent the gate electrode 4 and the field emission type cathode 6 from being short-circuited. Therefore, the short circuit between the cathode electrode 2 and the gate electrode 4 can be significantly suppressed.

Further, in this case, when the insulating coating layer 14 is applied to the inner surface of the hole 5, the inner diameter of the hole 5 can be finely adjusted. In FIG. 3, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted.

An example of a method of manufacturing such an electron emission source will be described in detail with reference to the manufacturing process diagrams of FIGS. First, as shown in FIG. 2A, on a cathode panel 1 made of glass or the like, a cathode electrode 2 made of Cr or the like, an insulating layer 3 made of SiO ₂ or the like, and Mo or Nb on the entire surface.
The gate electrodes 4 made of, for example, are sequentially laminated by sputtering, vacuum deposition, or the like. Although not shown, the insulating layer 3 and the gate electrode 4 are patterned by applying photolithography, RIE or the like as a stripe pattern extending in a direction orthogonal to the paper surface of FIG. Using this as a mask, RIE, wet etching and the like are performed to form the hole 5.

[0032] Next, as shown in FIG. 2B, so as to cover the gate electrode 4 above, diagonally SiO _2, SiN _X or Al ₂ O insulating coating layer 14 of, eg, SiO _2, such as _3, as shown by the arrow a Direction, such as 100
Deposition is about 200 nm. At this time, cathode panel 1
The insulating coating layer 14 can be applied so as to cover the inner surface of the hole 5 by rotating. Then, a sacrificial layer 22 made of, for example, Al such as Al or Ni is further deposited on the same by oblique vapor deposition, sputtering or the like.

Next, as shown by the arrow b in FIG. 2C, Mo is removed from the direction perpendicular to the surface of the cathode panel 1.
And the cathode material layer 23 is deposited by vapor deposition, sputtering or the like. At this time, on the gate electrode 4, the diameter of the hole 5 is gradually reduced in an oblique direction upward along the inner sidewalls of the hole 5 of the insulating coating layer 14 and the sacrificial layer 22 that are obliquely deposited. A cathode material layer 23 is deposited and deposited in the holes 5 in a substantially conical shape.

Then, the sacrificial layer 22 is dissolved by wet etching or the like to selectively remove the cathode material layer 23 laminated thereon, and the conical field emission type cathode 6 is formed in the hole 5. can do.

In the step of FIG. 2B, the insulating coating layer 1
It is also possible to form the same pattern as that of the gate electrode 4 by photolithography or the like without laminating the film 4 obliquely, for example, after laminating it on the gate electrode 4 and then successively depositing the insulating coating layer 14. Even in this case, as shown in FIG. 4, even if the conductive particles such as the metal particles 24 enter the hole 5 and come into contact with the cathode 6, it is possible to prevent the gate electrode 4 and the cathode 6 from being short-circuited. ,
It is possible to prevent a short circuit between the gate and the cathode. 4, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and duplicate description will be omitted.

In each of the above examples, a field emission type cathode is formed by depositing a conductive layer on a glass substrate as an electron emission source, but the present invention utilizes various other field emission effects. Can be applied to electron emission sources. For example, as shown in FIG. 5, using a Si substrate 31,
The structure of the present invention can be used when the substrate itself is processed to form the field emission cathode 6.

In this case, for example, a conical field emission type cathode 6 can be formed by patterning a mask having a plane circular shape at regular intervals on the substrate 31 and performing wet etching or the like using this as a mask. it can. Then, without removing the mask, the insulating layer 3 and the gate electrode 4 are deposited over the entire surface, and then the mask is dissolved and removed to surround the periphery of the field emission type cathode 6 to form the insulating layer 3 and the gate electrode 4. Stacked electron emission sources can be formed.

Then, after this, for example, in FIG.
As shown by (3), the insulating coating layer 14 made of SiO ₂ or the like is deposited from the oblique direction by vapor deposition, sputtering or the like. At this time, by rotating the Si substrate 31, the insulating coating layer 14 can be deposited so as to cover the gate electrode 4 over the inner surface of the hole 5.

Also in this case, even if the conductive fine particles enter the hole 5, a short circuit between the field emission cathode 6 and the gate electrode 4 can be prevented, and a short circuit between the cathode and the gate can be surely suppressed.

In each of the above-mentioned examples, SiO ₂ was used as the material of the insulating coating layer 14, but SiN _x , Al ₂
Various insulating materials such as O ₃ can be used. In particular, by setting the electric resistivity to be 10 ⁷ Ωcm or more, it is possible to reliably avoid the short circuit between the gate electrode and the field emission cathode due to the adhesion of the conductive fine particles when the voltage is applied,
An electron emission source and a display device using the same can be formed with a high yield. On the other hand, as in the above-mentioned Japanese Patent Laid-Open No. 4-229922, for example, 10 ²
When using a material having a relatively close resistivity of about 10 ⁵ Ωcm, the desired result was not obtained.

Further, as described above, in particular, by forming the insulating coating layer by oblique deposition such as oblique deposition, the work such as patterning the gate electrode separately from the underlying insulating layer 3 is performed. The side surface of the gate electrode can be surely and easily covered with the insulating material without any need, and the short circuit can be suppressed more effectively.

The present invention is not limited to the above-mentioned respective embodiments, and various modifications and changes can be made in the material constitution of the electron emission source, the material constitution of the phosphor screen constituting the display device, and the like. Needless to say.

[0043]

As described above, according to the present invention, since the insulating coating layer is provided on the gate electrode, the conductive fine particles and the like adhere to the field emission type cathode of the electron emission source including the field emission type cathode. Even in this case, the short circuit between the cathode and the gate electrode, and further the short circuit between the cathode electrode and the gate electrode can be significantly suppressed. Therefore, when a large number of cathodes are provided for the cathode electrode, the cathode line as a whole will not be short-circuited with the gate electrode even if the conductive fine particles adhere to a part of the cathode, and such a field emission type cathode will be used. For example, the yield of a so-called FED type display device in which several hundred millions are formed to form an electron emission source can be significantly improved.

Particularly, by forming the insulating coating layer with an insulating material such as SiO ₂ , SiN _x , Al ₂ O ₃ or the like or an insulating material having an extremely high resistivity of about 10 ⁷ Ωcm or more, the cathode-gate area can be more reliably formed. It is possible to avoid a short circuit.

By applying the above-mentioned insulating coating layer from an oblique direction, the inner surface of the hole of the gate electrode can be covered with the insulating material easily and surely without special patterning of the gate electrode. As a result, it is possible to more reliably avoid a short circuit between the gate electrode and the cathode,
Further, it is possible to finely adjust the inner diameter of the hole.

[Brief description of drawings]

FIG. 1 is an enlarged schematic cross-sectional view of a main part of an embodiment of the present invention.

FIG. 2A is a manufacturing process diagram of an embodiment of the present invention. B
FIG. 3 is a manufacturing process diagram of an example of the present invention. C is a manufacturing process diagram of an example of the present invention. D is a manufacturing process diagram of an embodiment of the present invention.

FIG. 3 is a schematic enlarged cross-sectional view of a main part of an embodiment of the present invention.

FIG. 4 is a schematic enlarged cross-sectional view of a main part of another embodiment of the present invention.

FIG. 5 is a schematic enlarged cross-sectional view of a main part of another embodiment of the present invention.

FIG. 6 is an enlarged schematic perspective view of an example of a display device.

FIG. 7 is a schematic linear enlarged perspective view of a main part of an example of a field emission cathode.

FIG. 8 is an enlarged schematic cross-sectional view of a main part of an example of a field emission cathode.

[Explanation of symbols]

 1 Cathode Panel 2 Cathode Electrode 3 Insulation Layer 4 Gate Electrode 5 Hole 6 Field Emission Cathode 14 Insulation Coating Layer

Claims (5)

[Claims] 1. A field emission type cathode made of an electron emitting substance is provided on a cathode electrode, and a gate electrode having a hole corresponding to the field emission type cathode is disposed through an insulating layer. An electron emission source comprising the insulating coating layer for the gate electrode. 2. The electron emission source according to claim 1, wherein the insulating coating layer is made of one material selected from SiO ₂ , SiN _{x and} Al ₂ O ₃ . 3. The insulating coating layer has an electric resistivity of 10 ⁷
The electron emission source according to claim 1, wherein the electron emission source is made of an insulating material of Ωcm or more. 4. A method of manufacturing an electron emission source having a field emission type cathode made of an electron emission material, wherein an insulating material is obliquely deposited on a gate electrode to form an insulating coating layer. Method of manufacturing electron emission source. 5. A field emission type cathode made of an electron emitting substance is provided on the cathode electrode, and a gate electrode provided with a hole corresponding to the field emission type cathode is disposed with an insulating layer interposed therebetween. A display device comprising an emission source and a phosphor screen facing the electron emission source, wherein an insulating coating layer is provided on the gate electrode.