JP4749231B2 - Manufacturing method of electron emission device - Google Patents

Description

  The present invention relates to a method for manufacturing an electron emission device in which carbon nanotubes are used as an electron source.

Conventionally, research has been conducted on electron emission devices using carbon nanotubes as an electron source. In conventional electron emission devices, aging is performed in order to make the emission distribution of electrons emitted from carbon nanotubes uniform. Aging is a method of selectively eliminating the tip of a carbon nanotube having a high electron emission capability by flowing an excessive current. In conventional aging, a uniform emission distribution is realized by applying a voltage higher than the rated value between the cathode layer and the gate electrode layer to eliminate carbon nanotubes with high electron emission capability. .
JP 2006-12578 A

  According to the above aging, an excessive current is passed through the carbon nanotubes in order to make the electron emission distribution uniform. Therefore, the carbon nanotubes scatter and adhere to the gate electrode layer, so that the insulation between the cathode layer and the gate electrode layer is lowered. Moreover, the area which does not discharge | release an electron will be formed in a carbon nanotube layer by scattering of a carbon nanotube. As a result, the luminance is reduced or pixel defects are generated. Therefore, the display performance of the electron emission device is degraded.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a method for manufacturing an electron-emitting device having a uniform emission distribution.

  The electron-emitting device manufactured by the manufacturing method of the present invention includes a cathode substrate and an anode substrate that face each other through a space maintained in a vacuum state. The cathode substrate is electrically insulated from the anode substrate, the cathode layer provided on the substrate so as to face the anode substrate, the carbon nanotube layer containing carbon nanotubes provided on the cathode layer, and carbon It has an insulating layer provided on the nanotube layer and a gate electrode layer provided on the insulating layer. In the manufacturing method of the electron-emitting device of the present invention, a pulse voltage is applied between the cathode layer and the other electrode layer, and aging of the carbon nanotube is performed.

  In aging, the pulse voltage applied between the cathode layer and the other electrode layer is a peak of the voltage applied between the cathode layer and the other electrode layer when the electron-emitting device is actually driven. Greater than the intensity. Further, the duty ratio of the pulse voltage applied between the cathode layer and the other electrode layer is such that the voltage applied between the cathode layer and the other electrode layer when the electron-emitting device is actually driven. Less than duty. In addition, when aging is being performed, the average value of the power applied to the interface by the current passing through the interface between the carbon nanotube layer and the cathode layer is the actual value when the electron emission device is driven. It is smaller than the average value of the electric power given to the interface by the current passing through the interface with the layer.

  According to said structure, aging can be performed, preventing that a carbon nanotube layer peels from a cathode layer. As a result, the emission distribution of the electron emission device can be made uniform.

Hereinafter, a method for manufacturing an electron-emitting device according to an embodiment of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a cross-sectional view schematically showing a cathode substrate 1 and an anode substrate 11 of an electron emission device 100 used in the manufacturing method of the first embodiment. This electron emission device 100 can perform aging.

  As shown in FIG. 1, a cathode substrate 1 includes a plurality of cathode layers 3 on a main surface of a glass substrate 2 as an example of a substrate of the present invention. The cathode layer 3 is provided in a line shape. A carbon nanotube layer 4 containing carbon nanotubes 4 a is formed on the main surface of the cathode layer 3. In the present embodiment, the carbon nanotube layer 4 is formed by a printing method. An insulating layer 5 is formed so as to cover the carbon nanotube layer 4. The thickness of the insulating layer 5 is about 10 μm. Further, a plurality of gate electrode layers 6 are formed on the main surface of the insulating layer 5. The gate electrode layer 6 is a line-shaped metal electrode layer extending in a direction orthogonal to the cathode layer 3.

  The gate electrode layer 6 and the insulating layer 5 are provided with one electron passage hole 7 for each pixel. The carbon nanotube layer 4 is exposed on the bottom surface of the electron passage hole 7. The carbon nanotube layer 4 has carbon nanotubes 4a. The carbon nanotubes 4 a are subjected to a treatment for promoting field emission, and extend substantially perpendicular to the main surface of the cathode substrate 1. In addition, the carbon nanotube which performed such a process is called raising. The electron passage hole 7 has a rectangular shape with a short side length of 30 μm and a long side length of 300 μm.

  The anode substrate 11 and the cathode substrate 1 are installed at a distance of 60 μm via an insulating spacer. In aging, a voltage is applied between the cathode layer 3 and the gate electrode layer 6. This voltage is a voltage having a predetermined pulse waveform. Thereby, an emission current flows from the cathode layer 3 to the carbon nanotube layer 4. The anode layer 9 is applied with a potential that is higher than the potential peak applied to the gate electrode layer 6 with reference to the potential of the cathode layer 3. This potential is a constant value.

  For example, a potential of 0 V is applied to the cathode layer 3 and a positive pulse potential is applied to the gate electrode layer 6. The pulse voltage applied between the cathode layer 3 and the gate electrode layer 6 has a frequency of 480 Hz and a peak of 150V. In the pulse voltage, the duty Dy is 1/6144, and the pulse width is 3.4 μsec. The pulse voltage is applied between the cathode layer 3 and the gate electrode layer 6 in a line sequential manner.

  When a voltage larger than the rated value is applied between the cathode layer 3 and the gate electrode layer 6, electrons are emitted from the tip of the carbon nanotube 4 a due to an electric field generated between the cathode layer 3 and the gate electrode layer 6. . When a predetermined threshold current, for example, a current larger than 1 μA flows through one carbon nanotube 4a, the carbon nanotube 4a is destroyed and disappears by Joule heat. On the other hand, the carbon nanotubes 4a through which a current equal to or lower than the threshold current flows are not destroyed and remain. Therefore, only the carbon nanotubes 4a having a large amount of electron emission are selectively lost. In other words, only the carbon nanotubes 4 a having an electron emission amount equal to or less than a predetermined threshold remain on the cathode layer 3. Therefore, the emission distribution of the carbon nanotube layer 4 can be made uniform.

  The aforementioned process is called aging. In FIG. 3, the change in the luminance distribution before and after aging is shown by a histogram. From FIG. 3, it can be seen that after aging, the number of dots with high luminance is reduced and the range of the luminance distribution is narrower than before aging.

  However, even when a current of 1 μA or less flows through the carbon nanotube 4a, the contact resistance at the interface between the carbon nanotube layer 4 and the cathode layer 3 is larger than the resistance of the carbon nanotube layer 4 itself, and the interface is destroyed by Joule heat. It is easy to be done. The amount of heat generated at the interface between the carbon nanotube layer 4 and the cathode layer 3 is proportional to the time during which a current flows through the carbon nanotube 4a. For this reason, if the duty (Dy) of the voltage applied between the gate electrode layer 6 and the cathode layer 3 is small, the amount of heat generated at the interface between the carbon nanotube layer 4 and the cathode layer 3 is small. Destruction caused by is unlikely to occur.

According to the manufacturing method of the electron-emitting device of the present embodiment, in aging, as shown in FIG. 4, the pulse voltage (Kp) applied between the cathode layer 3 and the gate electrode layer 6 is an electron. It is larger than the intensity (K _Q ) of the peak of the voltage applied between the cathode layer 3 and the gate electrode layer 6 when the emission device 100 is actually driven. In addition, the duty ratio (P / P _O ) of the pulse voltage applied between the cathode layer 3 and the gate electrode layer 6 in aging is such that the cathode layer 3 and the gate electrode when the electron emission device 100 is actually driven. It is smaller than the duty ratio (Q / Q _O ) of the voltage applied between the layers 6. Further, as shown in FIG. 4, the average value of the electric power applied to the interface by the current passing through the interface between the carbon nanotube layer 4 and the cathode layer 3 during the aging (the area of the hatched portion in FIG. 4). ) Is the average value of the power applied to the interface by the current passing through the interface between the carbon nanotube layer 4 and the cathode layer 3 when the electron emission device 100 is actually driven (in the region surrounded by the broken line in FIG. 4). Smaller than area). As a result, unnecessary carbon nanotubes 4a can be eliminated while suppressing thermal destruction of the interface between the carbon nanotube layer 4 and the cathode layer 3. Therefore, the emission distribution can be made uniform while preventing the carbon nanotubes 4a from being separated from the cathode layer 3.

As described above, even when the duty (Dy = P / _PO ) of the voltage applied between the cathode layer 3 and the gate electrode layer 6 in aging is small, the carbon nanotubes 4a having a large electron emission amount are obtained. Since it is destroyed, the effect of equalizing the emission distribution is not reduced.

  FIG. 5 shows the relationship between the duty ratio of the electric field applied between the cathode layer 3 and the gate electrode layer 6 and the current that occurs during aging and causes the carbon nanotube layer 4 to peel off from the cathode layer 3. . As can be seen from FIG. 5, when the duty of the voltage pulse in aging is reduced, the current density when the carbon nanotube layer 4 is separated from the cathode layer 3 is increased. Therefore, by reducing the duty ratio of the voltage pulse in aging, the emission distribution can be made uniform while preventing the carbon nanotubes 4a from being peeled off.

Embodiment 2. FIG.
Next, the manufacturing method of the electron-emitting device of Embodiment 2 of this invention is demonstrated using FIG.

  FIG. 2 is a cross-sectional view schematically showing the cathode substrate 1 and the anode substrate 11 of the electron emission device used in the manufacturing method of the present embodiment. This electron emission device can perform aging. In FIGS. 1 and 2, the portions denoted by the same reference numerals are portions that perform the same function, and thus description thereof will not be repeated.

In the manufacturing method of the electron-emitting device of the first embodiment, a voltage pulse is applied between the cathode layer 3 and the gate electrode layer 6. In the manufacturing method of the electron-emitting device of the present embodiment, the cathode layer A voltage pulse is applied between 3 and the anode layer 9. In the voltage pulse, the peak is 1000 V, the frequency is 48 Hz, the duty Dy (= P / P _O ) is 1/6144, and the width is 3.4 μsec. The pulse voltage is applied in a line sequential manner.

  The anode layer 9 is formed in a stripe shape. The cathode layer 3 and the anode layer 9 are arranged so that the center line of the anode layer 9 and the center line of the cathode layer 3 face each other in parallel. Since the anode layer 9 is formed in a stripe shape, the capacitance between the cathode layer 3 and the anode layer 9 is small. Therefore, the rise time of the pulse voltage applied between the anode layer 9 and the cathode layer 3 is several tens of ns. When a voltage is applied between the cathode layer 3 and the anode layer 9, electrons are emitted from the tip of the carbon nanotube 4a.

  As in the first embodiment, when a current larger than a predetermined threshold current, for example, 1 μA, flows through one carbon nanotube 4a, the carbon nanotube 4a is destroyed and disappears due to Joule heat. On the other hand, the carbon nanotubes 4a through which a current equal to or lower than the threshold current flows are not destroyed and remain. Therefore, only the carbon nanotubes 4a having a large amount of electron emission are selectively lost. In other words, only the carbon nanotubes 4 a having an electron emission amount equal to or less than a predetermined threshold remain on the cathode layer 3. As a result, the emission distribution of the carbon nanotube layer 4 can be made uniform.

  Similarly to the first embodiment, even when a current of 1 μA or less flows through the carbon nanotube 4a, if the duty (Dy) of the voltage applied between the cathode layer 3 and the gate electrode layer 6 is small, the cathode The amount of heat generated at the interface between the layer 3 and the carbon nanotube layer 4 is small.

  Also in the aging of the present embodiment, as in the aging of the first embodiment, the relationship between the pulse voltage in aging and the voltage when the actual electron emission device is driven is as shown in FIG. It becomes.

That is, in the manufacturing method of the electron-emitting device 100 of the present embodiment, as in the first embodiment, the aging is applied between the cathode layer 3 and the gate electrode layer 6 as shown in FIG. The pulse voltage (Kp) applied is larger than the peak intensity (K _Q ) of the voltage applied between the cathode layer 3 and the gate electrode layer 6 when the electron-emitting device 100 is actually driven. In addition, the duty ratio (P / P _O ) of the pulse voltage applied between the cathode layer 3 and the gate electrode layer 6 in aging is such that the cathode layer 3 and the gate electrode when the electron emission device 100 is actually driven. It is smaller than the duty ratio (Q / Q _O ) of the voltage applied between the layers 6.

  Further, as shown in FIG. 4, the average value of the electric power applied to the interface by the current passing through the interface between the carbon nanotube layer 4 and the cathode layer 3 during the aging (the area of the hatched portion in FIG. 4). ) Is the average value of the power applied to the interface by the current passing through the interface between the carbon nanotube layer 4 and the cathode layer 3 when the electron emission device 100 is actually driven (in the region surrounded by the broken line in FIG. 4). Smaller than area). As a result, unnecessary carbon nanotubes 4a can be eliminated while suppressing thermal destruction of the interface between the carbon nanotube layer 4 and the cathode layer 3. Therefore, the emission distribution can be made uniform while preventing the carbon nanotubes 4a from being separated from the cathode layer 3.

  In the first and second embodiments, the gate electrode layer or anode layer used for aging and the gate electrode layer or anode layer used when the electron-emitting device is actually driven are the same. However, in order to prevent the gate electrode layer or the anode layer from being damaged by a large amount of electron emission during aging, the gate electrode layer used for aging or the gate used when the electron emission device is actually driven. The electrode layer or the anode layer may be different. According to this, since the gate electrode layer or the anode layer damaged due to aging is not incorporated in the actual electron emission device, deterioration of the performance of the electron emission device due to aging is prevented.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

FIG. 3 is a cross-sectional view showing a cathode substrate and an anode substrate used in the method for manufacturing the field emission device of the first embodiment. FIG. 6 is a cross-sectional view showing a cathode substrate and an anode substrate used in the method for manufacturing the field emission device of the second embodiment. It is a histogram of the luminance distribution of the panel before aging and after aging. It is a figure which shows the relationship between the pulse voltage in an aging, and the pulse voltage when an actual electron emission apparatus is driven. It is a graph which shows the relationship between the duty of the electric field applied, and the current density of peeling of a carbon nanotube.

Explanation of symbols

  1 cathode substrate, 2 glass substrate, 3 cathode layer, 4 carbon nanotube layer, 4a carbon nanotube, 5 insulating layer, 6 gate electrode layer, 7 electron passage hole, 9 anode layer, 10 substrate, 11 anode substrate, 100 electron emission device .

Claims (4)

A cathode substrate and an anode substrate facing each other through a space maintained in a vacuum state;
The cathode substrate is
A cathode layer provided on the substrate so as to face the anode substrate while being electrically insulated from the anode substrate;
A carbon nanotube layer provided on the cathode layer and containing carbon nanotubes;
An insulating layer provided on the carbon nanotube layer;
A method for manufacturing an electron-emitting device having a gate electrode layer provided on the insulating layer, wherein a pulse voltage is applied between the cathode layer and another electrode layer to perform aging of the carbon nanotubes Comprising the steps of
In the aging, a pulse voltage applied between the cathode layer and another electrode layer is applied between the cathode layer and the other electrode layer when the electron-emitting device is actually driven. Greater than the peak intensity of the voltage
A duty ratio of a pulse voltage applied between the cathode layer and the other electrode layer is applied between the cathode layer and the other electrode layer when the electron emission device is actually driven. Less than the duty of the voltage to be
When the aging is being performed, the average value of the power given to the interface by the current passing through the interface between the carbon nanotube layer and the cathode layer is the carbon when the electron emission device is actually driven. A method for manufacturing an electron-emitting device, wherein the method is smaller than an average value of electric power applied to the interface by a current passing through the interface between the nanotube layer and the cathode layer.   The method for manufacturing an electron-emitting device according to claim 1, wherein the other electrode layer is the gate electrode layer.   The method of manufacturing an electron-emitting device according to claim 1, wherein the other electrode layer is the anode layer.   The method of manufacturing an electron-emitting device according to claim 1, wherein the other electrode layer used for the aging is different from the other electrode layer used when the electron-emitting device is actually driven.

Images