JP3879101B2 - FED device equipped with electron multiplier and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in FED (Field Emission Display), and relates to an FED device equipped with an electron multiplier (dynode) having high luminance characteristics and a method for manufacturing the same.
[0002]
[Prior art]
As a conventional FED, a spindt type FED described in Patent Document 1 is known (see FIG. 2). This type of FED has a cold cathode as an electron emission source formed in a sharp conical shape on a Si substrate, and applies a voltage between the cathode electrode and the gate to emit electrons from the cold cathode. FED. This type of cold cathode is formed by vacuum-depositing a material such as MO, Cr, or Pt having a low work function on the tip of the cathode substrate.
[0003]
The FED described in Patent Document 2 is a type generally referred to as carbon nanotubes / CNT FED (see FIG. 3). This type employs carbon nanotubes for the cold cathode.
[0004]
Patent Document 3 employs the above-described spind type, and describes an FED in which an electron multiplying layer for multiplying electrons emitted from a cold cathode by a cathode is mounted on a phosphor (see FIG. 11). ). According to this FED, the electrons 33 use the space 51 to impact the electron multiplication layer 50 by the spontaneous diffusion of electrons to generate secondary electrons, and excite the phosphor to emit light on the outside of the glass substrate. It is a mechanism.
[Patent Document 1]
US Pat. No. 3,665,241 [Patent Document 2]
JP 2002-343281 A [Patent Document 3]
US Pat. No. 5,982,082
[Problems to be solved by the invention]
However, these conventional FEDs still have many problems such as a limitation in light emission luminance and light emission uniformity and an increase in manufacturing cost.
[0006]
In both Patent Document 1 and Patent Document 2, the electron emitted from the cold cathode is directly applied to the light emitting layer to emit light, converted into an image or text, and displayed on the outside of the glass substrate. Yes. For this reason, the amount of electrons emitted from the cold cathode is directly reflected in luminance and contrast. However, the amount of electrons generated from these conventional cold cathodes is limited, and no electrons have been obtained until high-luminance emission is obtained. In addition, since light emission cannot be obtained uniformly, there has been a problem in using it for flat displays and the like that require high vision, for example.
[0007]
However, in the type of Patent Document 1, by forming the cold cathode serving as an electron emission source in a sharper cone shape, a higher degree of analysis than that of the type of Patent Document 2 can be obtained. It was costly. On the other hand, the type of Patent Document 2 can be reduced in cost as compared with the type of Patent Document 1, but has the disadvantages of low brightness and short life.
[0008]
The FED of Patent Document 3 uses an electron multiplication layer that multiplies electrons. However, only a single electron multiplication layer has a limited electron multiplication effect. In addition, since the electron multiplier layer 50 is bombarded by natural diffusion of electrons using the space 51 to generate secondary electrons, the single cathode electron source (emitter) 36 for each pixel is connected to each other pixel. It is necessary to isolate the emitter from the emitter with a certain distance. For this reason, the space 51 is not only complicated, but also disadvantageously increases in manufacturing cost.
[0009]
In addition, as an electron generation source, in the pn junction type shown in FIG. 4, the PN type cold cathode shown in FIG. 4A or the MIM type cold cathode shown in FIG. Alternatively, cold cathodes called surface emission / conduction emitters as shown in FIG. 5 have been proposed. However, the amount of electrons generated from the cold cathodes is limited, and high-luminance emission is obtained. No electrons have been obtained until they are made.
[0010]
Therefore, the present invention was created to solve the above-described problems, and can improve the emission brightness of the FED, maintain the initial light emission performance for a long time, and can be provided at low cost with excellent durability. The present invention provides an FED device equipped with a simple electron multiplier and a method for manufacturing the same.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention includes a glass substrate 1 having translucency, an anode ITO electrode 3 provided as an anode on the inner surface of the glass substrate 1, and an anode provided inside the anode ITO electrode 3. In an FED device having a light emitting layer 4 that emits light by impact of electrons generated from a cold cathode facing the ITO electrode 3 and transmits light to the outside of the glass substrate 1, the electron source of the cold cathode has a length as 10 disposed mu m was formed below CNT, as the luminescent layer 4, to form a light emitting layer 4 of thin film vacuum deposited on the hole has a large number of holes in the alloy of Ni and Fe Cu- A metal channel type electron multiplying portion 6 coated with a secondary electron generating material 9 of Be or Ag—Mg is disposed, and disposed between the cold cathode and the light emitting layer 4 via insulating layers 5 and 10. The primary electrons 7 generated from the cold cathode are electrons. When passing through the holes in the multiplier section 6, by applying an impact to the secondary electron generating material 9 is to allowed to increase secondary electrons 8 amount of radiation into the light emitting layer 4.
[0016]
The manufacturing method of the present invention includes a glass substrate 1 having translucency, an anode ITO electrode 3 provided as an anode on the inner surface of the glass substrate 1, and an anode ITO electrode 3 provided inside the anode ITO electrode 3. in FED device emitted by electron impact generated from opposite cold cathode and a luminescent layer 4 which allowed to transmit light to the outside of the glass substrate 1, the cathode ITO electrodes 15 CNT13 molded length below 10 mu m and a cold cathode manufacturing process for screen printing on an insulating layer 16 and the gate electrode 12 on the cathode ITO electrode 15 are sequentially formed by screen printing, to the hole has a large number of holes in the alloy of Ni and Fe A secondary channel generating material of Cu—Be or Ag—Mg is applied to provide a metal channel type electron multiplier, and the electron multiplier is disposed on the gate electrode 12 via an insulating layer 16. After the electron-multiplier mounting step, the periphery of the glass substrate 14 with the anode ITO electrode 3 and the cathode ITO electrode 15 is sealed with a glass frit, the inside of the device is 10-6 torr with a vacuum pump And a vacuum process for setting the vacuum.
[0019]
According to the present invention, when primary electrons emitted from the cold cathode pass through the electron multiplier section 6, they are emitted to the light emitting layer 4 as secondary electrons having an increased amount of electrons, and promote high-luminance emission. It is.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The basic configuration of the present invention is such that an electron multiplier 6 for increasing the amount of electrons is attached to an FED device.
[0021]
The FED device includes a transparent glass substrate 1, an anode ITO electrode 3 provided as an anode on the inner surface of the glass substrate 1, and a cold cathode provided inside the anode ITO electrode 3 and facing the ITO electrode 3. And a light emitting layer 4 that emits light by the impact of electrons generated from the light and transmits the light to the outside of the glass substrate 1.
[0022]
The electron multiplier 6 is mounted between the cold cathode and the anode of this FED device. When the primary electrons 7 generated from the electron multiplier 6 pass through the cavity of the electron multiplier 6, the secondary electron generating material 9 is impacted, and the amount of secondary electrons 8 emitted to the light emitting layer 4 is reduced. Increase it.
[0023]
A metal channel type electron multiplier 6A is used as the electron multiplier 6 most suitable for the present invention (see FIG. 13). In addition, a box type electron multiplier (see FIG. 6), a line focus type electron multiplier (see FIG. 7), a mesh type electron multiplier (see FIG. 8), and an MPC type electron multiplier. (See FIG. 9). However, in the present invention, these electron multipliers are not used .
[0024]
In particular, as the metal channel type electron multiplying unit 6A, any of the types shown in FIGS. That is, FIG. 4A shows a state in which the inner peripheral surface of the hole 6Aa coated with the secondary electron generating material 9 is curved. Further, in FIG. 6B, the inner peripheral surface of the hole 6Aa is cylindrical, and the opposing side surfaces are parallel. Further, FIG. 5C shows a state in which the inner peripheral surface of the hole 6Aa has a cylindrical shape and the opposing side surfaces are not parallel. As shown in the illustrated example, the single-layer metal channel type electron multiplier section 6A has a height (thickness) of about 0.2 mm, the diameter of the hole 6Aa is about 0.1 mm to 0.3 mm, 42% Ni and 58%. An alloy with Fe is used. Further, when the diameter of the cold cathode hole 6Aa is smaller than the diameter of the anode hole 6Aa (FIG. 3C), the light emitting material of the light emitting layer 4, the secondary electron generating material 9 and the like are cooled. It can be made difficult to deposit on the cathode. The secondary electron generating material 9 applied to the inner peripheral surface of the hole 6Aa is preferably Cu—Be (copper-beryllium) or Ag—Mg (silver-magnesium).
[0025]
The electron multiplier section 6 shown in FIG. 12 shows a state in which four electron multiplier sections 6 are stacked. In this case, the generation of secondary electrons 8 can be further increased. For example, if the gain of one sheet is U (= secondary electron generation number / primary electron generation number), the total gain of the n electron multipliers 6 superimposed is Ut = k · U ⁿ (k = constant). , N = number of electron multipliers 6). On the other hand, each electron multiplier section 6 is laminated via insulating layers 5 and 10, respectively. Since this electron multiplier section 6 also serves as a spacer, it supports the space of the FED device, The thickness of the insulating layers 5 and 10 can be reduced. In addition, since the electron multiplier section 6 and the insulating layers 5 and 10 can reinforce the support strength between the cold cathode and the anode of the FED device, it can be used as an FED device for a thin large screen.
[0026]
Next, a manufacturing method of the FED device of the present invention will be described based on an example in which a multiwall type CNT 13 is used as a cold cathode and a metal channel type electron multiplier 6A is provided in the electron multiplier 6. (See FIG. 1). For the sake of convenience, the manufacturing process will be described by being divided into a cold cathode manufacturing process, an electron multiplier mounting process, and a vacuum process.
[0027]
Cold cathode manufacturing process, an arc-squirrel charge method, using CNT13 multiwall type were molded length below 10 mu m. Next, the CNT 13 is screen-printed on the cathode ITO electrode 15 on the glass substrate 14 with a metal mask kneaded in silver paste and patterned. After the CNT 13 is baked, the CNT 13 is subjected to a surface treatment to produce a cold cathode.
[0028]
In the electron multiplier mounting step, first, the insulating layer 16 and the gate electrode 12 are formed on the cathode ITO electrode 15 by screen printing. Further, the metal channel type electron multiplier 6A is disposed from the insulating layer 16 to the upper side of the gate electrode 12 through the insulating layer 10 formed by screen printing. Although the metal channel type electron multiplier 6A in the illustrated example is a single layer, it can be laminated in a plurality of layers such as two layers or four layers shown in FIG. Further, the insulating layer 5 is screen-printed on the upper surface of the metal channel type electron multiplier 6A, and the black matrix 2 is applied to the upper end of the insulating layer 5 by spin coating. Then, the glass substrate 1 is mounted on the black matrix 2 to fix the metal channel type electron multiplier 6A. Inside the glass substrate 1, an anode ITO electrode 3 and a thin-film light emitting layer 4 which has been vacuum-deposited are provided in advance.
[0029]
In the vacuum process, the anode ITO electrode 3 and the cathode ITO electrode 15 are sealed around the glass substrate 14 with glass frit (not shown), and then the inside of the device is vacuum pumped. Set to a vacuum of 10 ^-6 torr.
[0030]
Next, experimental results of the FED device of the present invention manufactured as described above and a conventional FED device will be described (see FIGS. 14 and 15).
[0031]
FIG. 14A shows a conventional FED device in which the electron multiplier 6 is not mounted. At this time, the anode voltage (Va) = 500V, the gate voltage (Vg) = 0, and the cathode voltage (Vc) = − 270V. On the other hand, FIG. 5B shows the FED device of the present invention, which is equipped with a two-layer metal channel type electron multiplier. Here, the anode voltage (Va) = 650V, the gate voltage (Vg) = 0, the cathode voltage (Vc) = − 270V, the voltage between the second metal channel type electron multiplier and the ground (V2) = 150V, It is assumed that the electrode (V1) of the metal channel type electron multiplying unit 1 is 0.
[0032]
As a result, as shown in FIG. 15, the FED device of the present invention has a light emission luminance (B) vs. operation time (t), a cathode current (Ic) vs. operation time (t), as compared with a conventional FED device. It shows excellent characteristics. The solid line shown in the figure represents the emission luminance (B) and the cathode current (Ic) of the FED device of the present invention. The dotted line represents the light emission luminance (B) and the cathode current (Ic) of the conventional FED device. That is, in the conventional FED device, after the operation time (t) = 1500 hours, both the light emission luminance (B) and the cathode current (Ic) show changes over time. In the FED device of the present invention, both change over time. It is not allowed.
[0033]
FIG. 16 shows a light emission pattern of each FED element in FIG. FIG. 16 (a) shows the light emission patterns of the present invention and the conventional example, and both show the initial light emission patterns without the electron multiplier section 6 (see (1) and (2)). FIG. 6B shows a light emission pattern after the operation time (t) = 1500 hours has elapsed, and the present invention with the electron multiplier 6 attached is compared with a conventional example without the attachment (▲ 3). ▼, see (4)). The light emission luminance (B) at the initial light emission in FIG. 5A was 150 nits (Ic = 0.5 mA) (see (1) and (2)). On the other hand, in the same figure (b) showing the operation time (t) = 1500 hours elapsed, the conventional FED device did not emit light from the FED element (see (4)). At this time, it was found that the FED element of the FED device of the present invention emits light even with emission luminance (B) = 100 nits (see (3)). At this time, the cathode current (Ic) is both reduced to 0.004 mA. The cause of this is thought to be that the material of the CNT has deteriorated due to changes over time. Therefore, the lifetime of the FED device can be extended by using CNTs having excellent durability performance.
[0034]
From these results, the following features were demonstrated by attaching the electron multiplier to the FED device. First, the emission luminance is improved. Second, the cathode response performance is improved. Third, to reduce the cathode current and extend the life of the cathode. Fourth, since the high luminance and response characteristics are good, it is not necessary to drive the circuit with an active device such as a TFT. In particular, the fourth characteristic is an important characteristic for reducing the manufacturing cost of the FED device.
[0035]
In the experiment of FIG. 14B, the electron multiplication gain (U) = 5 when the electron multiplication unit 6 (metal channel type electron multiplication unit) is further used. If 6 with two layers, the overall gain (Ut) = 5 ² were obtained. Therefore, the overall gain when the electron multiplier section 6 is an n-layer is represented by Ut = k · U ⁿ (k = constant number).
[0036]
【The invention's effect】
The present invention achieves the original object by being configured as described above.
[0037]
That is, the electron multiplying portion 6 in which the secondary electron generating material 9 is applied to a large number of cavities is disposed between the cold cathode and the light emitting layer 4 via the insulating layers 5 and 10 to generate the primary generated from the cold cathode. When the electrons 7 pass through the cavity of the electron multiplier 6, the secondary electron generating material 9 is bombarded to increase the amount of secondary electrons 8 emitted to the light emitting layer 4, thereby improving the emission brightness of the FED. It became possible to make it. In addition, by interposing the electron multiplier 6 between the cold cathode and the anode, the electron multiplier 6 itself plays the role of a spacer, increasing the strength of the FED device, thinner than the conventional, A wide range of FED devices can be provided.
[0038]
Moreover, by using carbon nanotubes as the electron source 17 of the cold cathode, it is possible to use it at a low voltage, and it can be provided at low cost with excellent durability.
[0039]
By using the metal channel type electron multiplier 6A for the electron multiplier 6, it is possible to maintain the initial light emission performance for a long time.
[0040]
Furthermore, according to the production method of the present invention, production based on screen printing becomes possible and can be provided at a very low cost.
[0041]
As described above, according to the present invention, various advantageous effects such as improving the light emission luminance of the FED, maintaining the initial light emission performance for a long time, and providing it with excellent durability and low cost can be provided. It is what you play.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an embodiment of the present invention.
FIGS. 2A and 2B show another type of electron generation source, where FIG. 2A is a perspective view and FIG. 2B is a cross-sectional view.
FIGS. 3A and 3B show another type of electron generation source, where FIG. 3A is a perspective view and FIG. 3B is a cross-sectional view.
4A and 4B show another type of electron generation source, where FIG. 4A is a cross-sectional view of a PN type, and FIG. 4B is a cross-sectional view of an MIM type.
FIG. 5 is a schematic diagram showing another type of electron source.
6A and 6B show another electron multiplier section, where FIG. 6A is a perspective view, and FIG.
FIG. 7 is a cross-sectional view of a main part showing another electron multiplier.
FIG. 8 is a schematic view showing another electron multiplier section.
9A and 9B show another electron multiplier section, where FIG. 9A is a partially cutaway perspective view, and FIG.
10A and 10B show another electron multiplier section, where FIG. 10A is a cross-sectional view, and FIG.
FIG. 11 is a schematic cross-sectional view showing a conventional FED device.
FIG. 12 is a schematic sectional view showing another embodiment of the present invention.
FIGS. 13A to 13C are perspective views showing the main part of an embodiment of a hole in the metal channel type electron multiplier of the present invention.
14A and 14B are schematic diagrams showing a test method using an FED device, wherein FIG. 14A shows the present invention and FIG. 14B shows a conventional example.
FIG. 15 is a graph showing the result of a test using the present invention and a conventional FED device.
FIG. 16 shows a light emission pattern of a test using the present invention and a conventional FED device, where (A) is an initial light emission pattern, and (B) is a light emission pattern after aging.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Black matrix 3 Anode ITO electrode 4 Light emitting layer 5 Insulating layer 6 Electron multiplication part 7 Primary electron 8 Secondary electron 9 Secondary electron generating material 10 Insulating layer 11 Vacuum 12 Gate electrode 13 CNT
14 Glass substrate 15 Cathode ITO electrode 16 Insulating layer 17 Electron generation source

Claims (2)

A light-transmitting glass substrate, an anode ITO electrode provided as an anode on the inner surface of the glass substrate, and light emitted by the impact of electrons generated from a cold cathode provided inside the anode ITO electrode and facing the anode ITO electrode in and FED device having a light emitting layer allowed to transmit light to the outside of the glass substrate, as an electron source of the cold cathode, is disposed a CNT formed by molding a length below 10 mu m, as the light-emitting layer, to form a light emitting layer of a thin film that is vacuum deposited, Ni and alloy metal channel electron multiplier coated with secondary electron generating material Cu-be or Ag-Mg in said hole has a large number of holes of the Fe And a secondary electron generating material when primary electrons generated from the cold cathode pass through the holes of the electron multiplying portion. Applying an impact to the light emitting layer FED device equipped with electron multiplying section, characterized in that allowed to increase the amount of secondary electrons to morphism. A light-transmitting glass substrate, an anode ITO electrode provided as an anode on the inner surface of the glass substrate, and light emitted by the impact of electrons generated from a cold cathode provided inside the anode ITO electrode and facing the anode ITO electrode And a light emitting layer that transmits light to the outside of the glass substrate, and a method for manufacturing an FED device in which an electron multiplying portion coated with a secondary electron generating material is disposed between the cold cathode and the light emitting layer. and a cold cathode manufacturing process for screen printing molded CNT on the cathode ITO electrode length below 10 mu m, to form an insulating layer and a gate electrode sequentially by screen printing on the cathode ITO electrode, Ni and Fe the alloy many holes in the hole has a Cu-be or Ag-Mg secondary electron generating material is applied providing a metal channel electron multiplier unit, the electronic multiplier section, on the gate electrode Isolated on The step of mounting the electron multiplying portion disposed through the substrate, and the periphery of the glass substrate having the anode ITO electrode and the glass substrate having the cathode ITO electrode sealed with a glass frit, and the inside of the device by a vacuum pump 10 A method for manufacturing an FED device equipped with an electron multiplier, characterized by comprising a vacuum step of setting a vacuum of -6 torr.

Images