JP2005149850A - Cold cathode field emission device, cold cathode field emission display device, and their manufacturing methods - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold cathode field emission device excellent in light emitting property, having reliable emitters, made possible to reduce a drive voltage and improve focus property, a cold cathode electric field electron emitting display device including this element, and their manufacturing methods. <P>SOLUTION: The cold cathode field emission display element 26 comprises a field emission device 1, comprising a three pole structure which comprises a cathode 6, a gate electrode 4 and an emitter 7 which is an electron emitting part connected to the cathode 6 on a substrate 3. The cathode 6 and the emitter 7 are made in order on a lower gate electrode 13 and an insulation layer 5 on the substrate 3 and a columnar gate electrode 12 is formed to face to the emitter 7. A gate electrode 4 comprises the lower gate electrode 13 and a columnar gate electrode 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cold cathode field emission display (so-called field emission display: FED), a manufacturing method thereof, and a cold cathode field emission device used in the display.

  Conventionally, as shown in FIG. 5, a field emission display (FED) has a cathode electrode 42, a gate electrode 44, a cathode electrode 42, and a cathode electrode on the inner surface of one flat glass substrate, a so-called back substrate 41. A cathode substrate 47 having a tripolar structure composed of an emitter 46 serving as a connected electron emission portion and an anode substrate 55 having a fluorescent surface 52 formed on the inner surface of the other flat glass substrate, ie, a so-called front substrate 51, sandwich a vacuum space. It is arranged and configured. The cathode substrate 47 is formed with a plurality of striped cathode electrodes 42 on the inner surface of the back substrate 41, an insulating layer 43 is formed to cover the cathode electrode 42, and a plurality of layers orthogonal to the cathode electrode 42 are formed on the upper surface of the insulating layer 43. The stripe-shaped gate electrode 44 is formed, and an emitter 46 is formed on the cathode electrode 42 facing the bottom of an opening (so-called gate hole) 45 formed at the intersection of the cathode electrode 42 and the gate electrode 44. The The anode substrate 55 forms, for example, red (R), green (G), and blue (B) phosphor stripes 52 [52R, 52G, 52B] on the inner surface of the front substrate 51 so as to face the emitter 46. A black matrix pattern, for example, a carbon stripe (CS) 53 is formed between the adjacent color phosphor stripes 52R, 52G, and 52B, and a metal back layer 54 is deposited on the front surface. A plurality of the openings 45 are provided corresponding to the respective color phosphor stripes 52, but are represented by one opening in FIG.

  In this field emission display, the field emission of electrons e from the emitter 46 is controlled by the gate electrode, and the field emitted electrons e are attracted to the anode potential to reach the anode substrate 55 to excite and emit the phosphor stripes 52. A required image is displayed. The field emission of electrons e includes an extraction method based on an anode potential, a extraction method based on a gate potential, and a method that accelerates using an anode potential.

When manufacturing such a field emission display, there are two types of processes for forming the emitter. A “first-in process” in which the emitter 46 is formed before the insulating layer 43 is formed and a gate hole 45 are formed. A “post-insertion process” is later considered to form the emitter 46 later.
In Patent Document 1, a first panel having a cold cathode field emission device in an effective area and a second panel having a phosphor layer and an anode electrode in an effective area are arranged opposite to each other with a vacuum layer VAC interposed therebetween. A flat-type display device in which a cold cathode field electron-emitting device comprises a cathode and a gate formed through an insulating layer thereon, and a focus type electron-emitting device formed on the cathode at the bottom of the opening Is disclosed.
JP 2001-210225 A

  In the above-described first-in process of the emitter 46, the emitter material is physically or chemically damaged by heat or chemicals during the process due to a plurality of processes such as a stacking process of the insulating layer 43 and the gate electrode 44 and etching. In addition, a design that takes into account the interlayer adhesion of each layer is also required, and further, there are various restrictions due to changes in materials and physical characteristics in order to improve emitter characteristics.

Therefore, it is considered that the post-insertion process of the emitter 46 is effective in reducing the damage received by the emitter material in the process. However, in this case, in the method in which the emitter material is directly injected into the bottom of each of the gate holes 45, the alignment accuracy becomes a problem. Further, when the emitter material is injected, if the emitter material 46 adheres to the wall surface of the gate hole 45, a current leak occurs between the gate and the cathode. When current leakage occurs, problems such as difficulty in applying a desired electric field to the emitter 46 occur.
In the above-described structure, since the distance between the gate electrode 44 and the emitter 46 affects the light emission characteristics, a dry process using a vacuum apparatus is necessary to form the uniform insulating layer 43, compared with the wet process. Cost increases.

  In view of the above-described points, the present invention provides a cold cathode field emission device having a highly reliable emitter, excellent light emission characteristics, further reducing drive voltage and improving focus characteristics, and the cold cathode The present invention provides a cold cathode field emission display device including a field electron emission device and a method of manufacturing the same.

  The cold cathode field emission display device of the present invention is a cold cathode field emission device having a three-electrode structure comprising a cathode electrode, a gate electrode, and an emitter serving as an electron emission portion connected to the cathode electrode on a substrate. A cathode electrode and an emitter are sequentially formed on the substrate via a lower gate electrode and an insulating layer, a columnar gate electrode facing the emitter is formed, and the gate electrode is composed of the lower gate electrode and the columnar gate electrode. It is characterized by that.

  In the cold cathode field emission device of the present invention, a columnar gate electrode is preferably formed higher than the surface of the emitter.

  The cold cathode field emission display according to the present invention has a tripolar structure comprising a cathode electrode, a gate electrode, and an emitter serving as an electron emission portion connected to the cathode electrode on a substrate. A lower gate electrode is formed below through an insulating layer, a columnar gate electrode facing the emitter is formed at the intersection of the cathode electrode and the lower gate electrode, and the gate electrode is integrated with the lower gate electrode. A cold cathode field emission device comprising a gate electrode is provided.

  In the cold cathode field emission display device of the present invention, it is preferable that the columnar gate electrode of the cold cathode field emission device is formed higher than the surface of the emitter.

  The manufacturing method of a cold cathode field emission device according to the present invention includes a step of forming a stripe-shaped lower gate electrode on a substrate, and forming a cathode electrode on the lower gate electrode via an insulating layer, on the cathode electrode. A step of forming an emitter, a step of patterning the emitter and the cathode electrode in a stripe shape so as to have a first opening at the intersection of the lower gate electrode, and a first opening of the insulating layer using a resist as a mask A step of forming a second opening reaching the lower gate electrode in a portion to be formed, and a step of forming a columnar gate electrode connected to the lower gate electrode and planted in the first and second openings To do.

  In the manufacturing method of the cold cathode field emission device of the present invention, it is preferable that the columnar gate electrodes are laminated by plating.

  In the cold cathode field emission device according to the present invention, a gate electrode is formed of a lower gate electrode formed below the cathode electrode and a columnar gate electrode planted opposite to the emitter, so that the emitter is located at the top of the substrate. The influence of process damage on the emitter material formed on the upper surface can be reduced. Since the emitter faces the columnar gate electrode without passing through the insulating layer, the thickness of the insulating layer does not affect the light emission characteristics. Since the emitter is formed on the uppermost surface, the effective area of the emitter is expanded and the amount of electron emission is increased.

  Since the cold cathode field emission display device of the present invention includes the cold cathode field emission device, the light emission characteristics do not depend on the thickness of the insulating layer between the cathode electrode and the gate electrode. Since the amount of electron emission increases, the light emission efficiency is improved. Since the distance between the emitter and the columnar gate electrode can be reduced, the control voltage applied to the gate electrode can be lowered. The emitter faces the side surface of the columnar gate electrode, and the spread of electrons emitted from the emitter is suppressed.

  In the method of manufacturing a cold cathode field emission display according to the present invention, the emitter is formed as the uppermost layer, and there is no process of stacking other layers on the emitter, so that the emitter material is not subject to process damage. First, an emitter is formed, a first opening is formed in the emitter and cathode electrodes, a second opening is formed in an insulating layer using a resist as a mask, and then a columnar gate electrode connected to the lower gate electrode is formed. Therefore, the alignment between the emitter and the columnar gate electrode becomes accurate, and the short circuit accident between the gate and the cathode does not occur as in the emitter post-insertion process method. The distance between the emitter and the columnar gate electrode is determined by the film thickness of the resist mask when the columnar gate electrode is formed, and can be reduced.

According to the cold cathode field emission device of the present invention, since the influence of process damage on the emitter is small, the deterioration of electron emission is small and the reliability of the emitter is enhanced. Further, since the effective area of the emitter is widened, for example, when the emitter is formed of a layer containing an electron emitting material such as carbon nanotubes, the number of light emitting sites, that is, the number of emitters that emit electrons by passing a current can be increased. . Accordingly, the increase in the number of light emitting sites and the small influence of process damage on the emitter can improve the light emission characteristics when applied to a cold cathode field emission display. The distance between the columnar gate electrode and the cathode electrode can be reduced.
By extending the columnar gate electrode higher than the emitter surface, it is possible to form a tripolar structure in which the light emission characteristics do not affect the thickness of the insulating layer. Since the light emission characteristics do not depend on the thickness of the insulating layer, the degree of freedom in designing a cold cathode field emission device having a tripolar structure can be increased. For this reason, the manufacturing process can be simplified, for example, a printing process can be used in manufacturing.

According to the cold cathode field emission display device of the present invention, since the cold cathode field emission device described above is provided, the light emission characteristics can be improved. When electrons are taken out by an anode electric field (when the anode is pulled), the columnar gate electrode suppresses the spread of electrons emitted from the emitter, so that the focus characteristic is improved.
Since it is easy to reduce the distance between the cathode electrode and the gate electrode, the drive voltage for light emission, that is, the gate-cathode voltage can be lowered.

  According to the manufacturing method of the cold cathode field emission display device of the present invention, it is possible to reduce damage to the emitter that is received from the process. Since the emitter is formed on the uppermost surface of the substrate, it is not necessary to increase the interlayer adhesion as much as compared with the first-in process. For this reason, the degree of freedom in designing the emitter material is increased because, for example, an emitter material having a good light emitting state can be used even if the interlayer adhesion is not obtained, because it is not physically restricted. By forming the columnar gate electrode by plating, a conventional vacuum device such as sputtering is not used, so that the gate electrode can be manufactured at low cost. By taking the manufacturing process of the present invention, it is possible to manufacture a cold cathode field emission display having improved emitter reliability, excellent light emission characteristics, reduced drive voltage, and improved focus characteristics.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows one embodiment of a cold cathode field emission display according to the present invention, and FIG. 2 shows a perspective view of its main part, that is, a cold cathode field emission device.
The cold cathode field emission display device 1 according to this embodiment is connected to a cathode electrode 6, gate electrodes 4, 12, 13, and the cathode electrode 6 on the inner surface of one flat glass substrate so-called back substrate 3. On the inner surface of a cold cathode field electron emission element 26 having a three-pole structure composed of an emitter 7 serving as an electron emission portion, a cathode substrate 27 on which the cold cathode field electron emission element 26 is formed, and the other flat glass substrate so-called front substrate 21 An anode substrate 25 on which a phosphor screen 28 (not shown) is formed is arranged with a vacuum space in between.

  As shown in FIGS. 1 and 2, the cold cathode field emission device 26 has a plurality of striped lower gate electrodes 13 constituting the gate electrode 4 formed on the inner surface of the back substrate 3. A plurality of stripe-like cathode electrodes 6 are formed so as to be orthogonal to the stripe-like lower gate electrode 13 via an insulating layer 5, and an emitter 7 is formed on the upper surface of the cathode electrode 6. Furthermore, at the intersection of the lower gate electrode 13 and the cathode electrode 6, a plurality of planted columnar shapes integrated with the lower gate electrode 13 so as to penetrate the opening 11 formed through the emitter 7, the cathode electrode 6 and the insulating layer 5. The gate electrode 12 is formed. The columnar gate electrode 12 is formed at a required distance (gap) D from the inner walls of the emitter 7 and the cathode electrode 6. The gate electrode 4 includes a lower gate electrode 13 and a columnar gate electrode 12. The columnar gate electrode 12 is formed to be higher than the upper surface of the emitter 7. That is, the columnar gate electrode 12 is formed such that the height H1 from the upper surface of the substrate 3 to the upper surface of the columnar gate electrode 12 is larger than the height H2 from the upper surface of the substrate 3 to the upper surface of the emitter 7. .

  On the other hand, the anode substrate 25 shown in FIG. 1 has, for example, red (R), green (G), and blue so that the inner surface of the front substrate 21 faces the emitter 7 in each crossing region of the gate electrode 4 and the cathode electrode 6. Each color phosphor stripe 22 [22R, 22G, 22B] of (B) is formed, and a black matrix pattern, for example, a carbon stripe (CS) 23, is formed between adjacent color phosphor stripes 22R, 22G, 22B. The metal back layer 24 is formed by deposition. In FIG. 1, only the red phosphor stripe 22 </ b> R appears because the cross section is taken along the line AA in FIG. 2.

3A to 3E and FIGS. 4F to 4I show a method of manufacturing the above-described cold cathode field emission display device 1, particularly a cathode substrate 27 having the cold cathode field emission device 26 having a tripolar structure.
In the present embodiment, first, as shown in FIG. 3A, a conductive layer to be the lower gate electrode 13 is formed on the glass substrate 3 by sputtering or vapor deposition. Thereafter, a striped resist mask is formed by photolithography, and selective etching is performed to form a plurality of striped lower gate electrodes 13 so as to be arranged in parallel at a predetermined interval. Alternatively, a plurality of stripe-shaped lower gate electrodes 13 may be formed by pattern printing of a metal paste. For example, the thickness of the lower gate electrode 13 can be about 0.1 to 10 μm, the stripe width can be about 85 to 100 μm, and the stripe pitch can be about 120 to 150 μm.

  Next, as shown in FIG. 3B, the insulating layer 5 is formed on the entire surface of the substrate including the lower gate electrode 13 by sputtering, CVD (chemical vapor deposition), printing, or the like. An example of the thickness of the insulating layer 5 can be about 3 to 10 μm. The insulating layer 5 is a planarizing film.

  Next, as shown in FIG. 3C, the cathode electrode 6 and the emitter 7 are formed on the entire surface of the insulating layer 5 by sputtering, CVD, or the like so as to be sequentially stacked with a required film thickness. An example of the thickness of the cathode electrode 6 can be about 0.2 to 1 μm.

  Next, as shown in FIG. 3D, a resist mask (not shown) is formed on the emitter by photolithography, and a plurality of stripes are arranged in parallel so as to be orthogonal to the stripe-shaped lower gate electrode 13 by selective etching. The cathode stripe (laminated body of cathode electrode 6 and emitter 7) 8 is formed. During this selective etching, a plurality of first openings 15 reaching the insulating layer 5 are formed at the intersections of the lower gate electrode 13 and the cathode electrode 6. An example of the cathode stripe width can be about 350 μm to about 400 μm, and an example of the stripe pitch can be about 420 μm.

  Next, as shown in FIG. 3E, a resist film 9 is applied to the entire surface of the substrate including the cathode stripe 8. That is, the resist film 9 is applied so that its thickness H4 is larger than the thickness H3 of the cathode stripe. The thickness H4 of the resist film 9 is formed later. It is formed to be the same as the height H1 of the gate electrode column.

  Next, as shown in FIG. 4F, the resist film 9 is patterned to form a columnar gate having an opening with an opening width d2 narrower than the first opening width d1 at a position corresponding to the first opening 15 of the cathode stripe 8. A resist pattern 10 for a hole is formed. An example of the opening width d1 of this example is about 20 to 70 μm, and an example of the opening width d2 is about 10 to 40 μm.

  Next, as shown in FIG. 4G, using the resist pattern 10 as a mask, the insulating layer 5 is etched by chemical dry etching (CDE), reactive ion etching (RIE), sand blasting, or the like to form a second layer on the insulating layer 5. An opening 16 is formed, and a columnar gate opening 11 reaching the lower gate electrode 13 is formed.

  Next, as shown in FIG. 4H, a columnar gate integrated with the lower gate electrode 13 by filling the gate opening 11 with a gate electrode metal by electroplating or electroless plating while leaving the resist pattern 10 left. The electrode 12 is formed. That is, the gate electrode 4 is formed of the lower gate electrode 13 and the columnar gate electrode 12. An example of the height of the columnar gate electrode 12 can be about 3.5 to 4 μm.

  Next, as shown in FIG. 4I, the resist film 9 is peeled off to complete the cathode substrate 27 in which the intended cold cathode field emission device 26 is formed on the substrate 3.

  On the other hand, although not shown, a phosphor screen comprising a carbon stripe CS23 and red (R), green (G), and blue (B) phosphor stripes 22 [22R, 22G, 22B] on the other glass substrate 21. 28 is formed, and a metal back layer 24 is further formed to fabricate an anode substrate 25. Then, the cathode substrate 27 and the anode substrate 25 are hermetically sealed with a vacuum space in between, and the intended cold cathode field emission display device 1 shown in FIG. 2 is obtained.

According to the cold cathode field emission display device 1 according to the present embodiment, the emitter 7 of the cold cathode field emission device 26 having a three-pole structure is formed on the uppermost surface of the cathode substrate 27. Therefore, the deterioration of the field electron emission characteristics of the emitter 7 is reduced, and the quality of the emitter material can be prevented from being deteriorated.
Since the emitter 7 is formed on the uppermost surface of the cathode substrate 27, the effective emitter area becomes large. For example, when the emitter 7 is formed of a paste containing an electron emitting material such as carbon nanotube, the number of light emitting sites, that is, an emitter that emits electrons. The number increases, and a large amount of electron emission can be obtained.
In the method of taking out electrons from the emitter 7 by the anode electric field (when the anode is pulled), since the emitter 7 is located at a position lower than the columnar gate electrode 12, the spread of the electrons emitted from the emitter 7 is suppressed, and the focus characteristic is good. To.
Since the distance between the cathode electrode 6 and the columnar gate electrode 12 can be reduced, the drive voltage for light emission, particularly the gate-cathode voltage can be lowered.
Since the gate electrode 4 has a structure in which the columnar gate electrode 12 is implanted from the lower gate electrode 13 below the cathode electrode 6 and extends to the surface of the emitter 7, the light emission characteristics do not depend on the film thickness of the insulating layer 5. , Increase the degree of freedom in structural design.
Since the emitter 7 is formed on the uppermost surface of the cathode substrate 27, it is not necessary to increase the interlayer adhesion as much as compared with the conventional first-in process method. Therefore, since there is no physical restriction, the emitter material can be designed with a high degree of freedom such that an emitter material having a good light emitting state can be used even if interlayer adhesion is not achieved.

According to the manufacturing method of the cold cathode field emission display according to the present embodiment, the light emission characteristics are improved by extending the gate electrode 4 in a column shape from the lower layer of the cathode electrode 6 on which the emitter 7 is formed to the cathode surface. A structure that does not affect the thickness of the insulating layer 5 is adopted. By forming the columnar gate electrode 12 by plating, a conventional vacuum device such as sputtering is not used, so that the electrode can be manufactured at low cost.
Since the emitter 7 is on the uppermost surface of the substrate, the degree of freedom in material design is increased as long as there is no physical restriction. Since this manufacturing method itself does not select the substrate size, it is possible to easily realize an increase in the size of the electrode and insulating layer deposition apparatus and the etching apparatus. In this example, it is fabricated on a 3.5-inch glass substrate for the convenience of the apparatus.

It is sectional drawing of the cold cathode field electron emission apparatus which concerns on this Embodiment. It is a perspective view of the cold cathode field electron emission device according to the present embodiment. It is process drawing which shows the manufacturing method of the cold cathode field emission device concerning this embodiment. F to I are process diagrams showing a method for manufacturing a cold cathode field emission device according to the present embodiment. It is sectional drawing of the conventional cold cathode field electron emission apparatus.

Explanation of symbols

1 .. Cold cathode field emission device 3 .... Back substrate 4 .... Gate electrode 5 .... Insulating layer 6 .... Cathode electrode 7 .... Emitter 8 .... Cathode stripe 10 .... Resist pattern , 11 .. Openings for columnar gates, 12... Columnar gate electrodes, 13 .. Lower gate electrodes, 15... First openings, 16 .. Second openings, 21. 22G, 22B] .. Each color phosphor stripe, 23 .. Carbon stripe (CS), 25 .. Anode substrate, 26 .. Cold cathode field emission device, 27 .. Cathode substrate, 28 .. Phosphor screen, 41.・ Back substrate 42 ..Cathode electrode 43 ..Insulating layer 44 .Gate electrode 45 ..Opening 46 ..Emitter material 47 ..Cathode substrate 51 ..Front substrate 52 [52R, 52G, 52B] Each color phosphor stripes, 53 ... carbon stripes (CS), 54 ... metal back layer, 55 ... anode substrate

Claims (6)

A cold cathode field electron emission device having a three-electrode structure comprising a cathode electrode, a gate electrode, and an emitter serving as an electron emission portion connected to the cathode electrode on a substrate,
The cathode electrode and the emitter are formed on the substrate through a lower gate electrode and an insulating layer,
A columnar gate electrode facing the emitter is formed at the intersection of the cathode electrode and the lower gate electrode,
The cold cathode field emission device, wherein the gate electrode includes the lower gate electrode and the columnar gate electrode. The cold cathode field emission device according to claim 1, wherein the columnar gate electrode is formed higher than a surface of the emitter. A three-electrode structure comprising a cathode electrode, a gate electrode, and an emitter serving as an electron emission portion connected to the cathode electrode is formed on the substrate,
A lower gate electrode is formed through an insulating layer under the cathode electrode having the emitter,
A columnar gate electrode facing the emitter is formed at the intersection of the cathode electrode and the lower gate electrode,
A cold cathode field emission display comprising the cold cathode field emission device, wherein the gate electrode comprises the lower gate electrode and the columnar gate electrode integral with the lower gate electrode. The cold cathode field emission display according to claim 3, wherein the columnar gate electrode in the cold cathode field emission display is formed higher than a surface of the emitter. Forming a stripe-shaped lower gate electrode on the substrate;
Forming a cathode electrode on the lower gate electrode through an insulating layer, and forming an emitter on the cathode electrode;
Patterning the emitter and the cathode electrode in stripes so as to have a first opening at the intersection of the lower gate electrode;
Forming a second opening reaching the lower gate electrode in a portion corresponding to the first opening of the insulating layer using the resist as a mask;
Forming a columnar gate electrode connected to the lower gate electrode and planted in the first and second openings;
A method of manufacturing a cold cathode field emission display device. 6. The method of manufacturing a cold cathode field emission display according to claim 5, wherein the columnar gate electrode is formed by a plating method.

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