KR20070064233A - Image display device and display pannel - Google Patents

Abstract

An image display device and a display panel are provided to improve brightness by forming an electron emitter thinner than the other part. A plurality of thin film type electron emission elements are formed by laminating a lower electrode(11), an insulating layer, and an upper electrode. The thin film type electron emission elements are formed in a matrix on a rear substrate(10). A front substrate is disposed opposite to the rear substrate. Phosphors are disposed on the front substrate. A driving circuit is used for driving the display panel in order to emit electrons. A control circuit is used for controlling the driving circuit on the basis of an image signal.

Description

Image display device and display panel {IMAGE DISPLAY DEVICE AND DISPLAY PANNEL}

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows typically the thin film type | mold electron emitting element as an Example of this invention.

Fig. 2 is a diagram showing an example of the configuration of an image display device as an embodiment of the present invention.

FIG. 3 is a view showing a step of forming an electron emission electrode portion of an upper electrode in the thin film type electron emission element of FIG. 1 by local heating. FIG.

FIG. 4 is a diagram illustrating an effect of the thin film type electron emission device of FIG. 1. FIG.

5 is a diagram illustrating the action of thinning due to ion attack.

Fig. 6 is a diagram showing a step of forming an electron emission electrode portion of an upper electrode of a thin film type electron emission element by ion attack.

7 is an explanatory diagram of a prior art.

<Explanation of symbols for the main parts of the drawings>

2: scan driver

4: data driver

6: high voltage generation circuit

7: Video input terminal

8: video signal processing circuit

9: timing controller

10: back substrate (cathode substrate)

11: lower electrode

12: insulating film

14, 15: protective insulating film

16: metal film lower layer

18: upper metal film layer

20: upper bus electrode

31: scanning line

32: data line

34: anode line

100: display panel

131: electron emission electrode portion

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus using a thin film type electron emission element, and more particularly, to a configuration of a thin film type electron emission element for improving the brightness of a screen.

A display using a cold cathode electron emission device for emitting electrons in a two-dimensional shape (matrix shape) and used as an electron source is called a FED (Field Emission Display). The cold cathode electron source of this FED is classified into a field emission type electron source and a hot electron type electron source. The former belongs to a spin type electron source, a surface conduction electron source, and a carbon nanotube type electron source, and the latter includes a metal-insulator-metal (MIM) type, a metal-insulator-semiconductor, and a metal-insulator-metal layer. The thin-film electron source such as metal-insulator-semiconductor (MIS) type, metal-insulator-semiconductor-metal type, etc.

The MIM type electron source belonging to a thin film type electron source and the display apparatus using the same are disclosed, for example in Japanese Patent Application Laid-Open No. 2004-363075 and Japanese Patent Application Laid-Open No. 2001-243901. The structure and operation principle of the MIM type electron emission device constituting the MIM type electron source are shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2004-363075, for example. That is, in this FIG. 1, between the upper electrode 13 and the lower electrode 11, the drive voltage Vd of the polarity by which the upper electrode becomes a constant voltage is applied with respect to the lower electrode, and several nanometers (10 <^-9> m)-several tens The electric field in the thin insulating layer 12 at nm (10 ^-9 m) is set to about 1 to 10 MV / cm (10 ⁶ V / 10 ^-2 m). At this time, electrons near the Fermi level in the lower electrode 11 penetrate the barrier by a tunnel phenomenon, are injected into the conduction band of the insulating layer 12 which is the electron acceleration layer, and become hot electrons, and the conduction band of the upper electrode 13. Flows into. These hot electrons are scattered in the insulating layer 12 and in the upper electrode 13 to lose energy. However, some of the hot electrons that reach the surface of the upper electrode 13 with energy of the work function φ or more of the upper electrode 13 are discharged into the vacuum 23.

As described above, in the case of the thin film type electron emission device, energy loss due to scattering of hot electrons occurs in the upper electrode. Therefore, in order to reduce energy loss, it is desirable to make the upper electrode as thin as possible. In this way, the electron emission efficiency in a vacuum can be improved from a thin film type electron emission element, and a bright display device can be realized.

Therefore, in Japanese Unexamined Patent Application Publication No. 2001-243901, in order to increase the electron emission efficiency, for example, a thin film of iridium (Ir), a thin film of platinum (Pt), and a thin film of gold (Au) are used in this order, respectively. Laminated | stacked and formed in the thickness of about 1 * 10 <^-9> m, 1 * 10 <^-9> m, about ^{2-3x10 <-9>} m, and heat processing is performed after that. By this heat treatment, a small portion of the Ir thin film is used as a nucleus, and aggregation of the Au thin film in the vicinity thereof proceeds to form a plurality of island-shaped metal protrusions formed of Au and Ir, and agglomerated between these island-like protrusions. As a result, a flat metal thin film portion thinner than 5 × 10 ⁻⁹ m with less Au component is integrally connected to the plurality of metal protrusions, and is formed with good reproducibility in the state of coexistence. In other words, the heat treatment can generate a reconstruction of the thin film structure to realize thinning of one layer. In addition, hereinafter, the reconstruction of the thin film structure by the above heat treatment will be referred to as "islandization". By this islanding, electron emission is generated from the thinner and reconstructed flat metal thin film portion, and the electron emission efficiency is improved. The flat metal thin film portion reconstructed by the ailization is a composite having a multi-layered or mixed structure of Ir, Pt and Au.

However, the present inventors have engaged in the research and development of thin film type electron emission devices for image display devices, and found that the resistance of the upper electrode increases due to the ailization while designing, starting and verifying the FED.

Fig. 7 schematically shows the diode current Id (input and output characteristics) flowing between the electrodes of the thin film type electron emission element before and after the heat treatment. In Fig. 7, the horizontal axis is driving voltage Vd, and the vertical axis is diode current Id. The diode current Id is on a logarithmic scale. In addition, Vth is the threshold voltage of a diode characteristic, and Vh is the predetermined peak voltage of the drive voltage applied to the upper electrode and the lower electrode.

As can be clearly seen from the input / output characteristics of Fig. 7, it can be seen that the diode current CDd after the heat treatment has decreased in the diode current Id with respect to the property CD101 before the heat treatment. This indicates that the resistance of the upper electrode was increased as a result of reconstruction of the upper electrode by the islanding into an island-shaped metal projection and a thinner flat metal thin film portion. In the examination of the inventors, the sheet resistance of the upper electrode after heat processing became 2 to 5 times compared with that before heat processing.

On the other hand, the MIM type electron emitting element which is one of the thin film type electron emitting elements is comprised as shown in FIG. 10 of Unexamined-Japanese-Patent No. 2004-363075, for example. As can be clearly seen from the above, the upper electrode has a flat electron emission electrode portion contributing to the electron emission of the upper portion of the insulating layer, which is an electron acceleration layer, and an inverted approximately quadrilateral with the approximately flat electron emission electrode portion 131 at the bottom. And an upper bus electrode covering portion covering the upper emission electrode and the electron emission peripheral portion on the side surface of the substrate. And the electron emission peripheral part has a taper with respect to the said flat electron emission electrode part.

When a driving voltage of a polarity in which the upper electrode becomes a constant voltage is applied to the lower electrode between the lower electrode and the upper electrode, concentration of an electric field occurs in a rising portion from the flat electron emitting electrode portion of this taper, resulting in a large current. Will flow. For this reason, there is a problem in that a large order train is generated by the synergistic action with the resistance increase due to the above-mentioned ailization, and is easily disconnected at the raised portion of the taper.

In addition, when the sheet resistance of the upper electrode increases, a voltage drop occurs in the electron emission peripheral portion that does not contribute to the electron emission in the upper electrode, so that the effective driving voltage Vd decreases for the thin film type electron emission device, and the electron Emission efficiency also falls. In addition, when the driving voltage Vd is increased to compensate for this, the degree of the electric field concentration becomes larger and the reliability is lowered.

The present invention improves the electron emission efficiency at the electron emission electrode portion (electron emission portion) of the upper electrode in the thin film type electron emission element used for the display panel of the image display device, and at the portion except the electron emission electrode portion. Increasing the resistance accompanying the ailization is reduced to improve the reliability in the electron emission peripheral portion. And this invention provides the image display technique which can improve the brightness and reliability of an image.

This invention comprises the upper electrode of the thin-film-type electron emission element used for the display panel of an image display apparatus, for example from a plurality of dissimilar metals of iridium, platinum, and gold, and especially the electron emission part of the plurality of dissimilar metals. While making a composite by melting, the thickness is made thinner than the thickness of the other part in the upper electrode. The upper electrode of such a configuration enables efficient release of electrons from the electron emitting portion into the vacuum, and enables feeding of the electron emitting portion to the electron emitting portion without disconnection.

<Example>

The present embodiment relates to an image display technique for performing image display by using a thin film type electron emission element that emits electrons in a vacuum and having a three-layer structure composed of an upper electrode, an electron acceleration layer, and a lower electrode, in the pixel portion of the display panel. . Examples of the thin film type electron emission device include a MIM type in which a metal-insulator-metal is stacked, a MIS type in which a metal-insulator-semiconductor is stacked, a metal-insulator-semiconductor-metal type, and the like. EMBODIMENT OF THE INVENTION Hereinafter, the MIM type electron emission element which is a typical thin film type electron emission element, and the image display technique using the same are demonstrated. However, the present invention is not limited to the MIM type electron emission device and the image display technology using the same.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

1-6 is explanatory drawing of the Example of this invention. FIG. 1 is a block diagram schematically showing a thin film type electron emission element according to the present embodiment, FIG. 2 is a block diagram showing the configuration of main parts of the image display device according to the present embodiment, and FIG. 4 is a flowchart illustrating a process of forming an electron emission electrode portion (electron emission portion) of the upper electrode in the thin film type electron emission element of 1 by laser irradiation, and FIG. 4 is an effect of the thin film type electron emission element of FIG. 1. It is a figure explaining. 5 and 6 are explanatory diagrams of a technique for thinning the electron emission electrode portion (electron emission portion) of the upper electrode of the thin film type electron emission element by the ion attack by the rare gas, and FIG. 5 is the It is a schematic diagram explaining the effect | action of thinning, and FIG. 6 is a flowchart explaining the process of forming the electron emission electrode part (electron emission part) of the upper electrode of a thin film type electron emission element by an ion attack.

As shown in FIG. 2, the image display device according to the present embodiment includes a display panel 100 in which a plurality of thin film type electron emission elements are arranged in a matrix, and a scan driver (scanning line) as a driving circuit for driving the display panel 100. Drive circuit) 2, a data driver (data line drive circuit) 4 as a drive circuit, a high voltage generation circuit 6 for generating a high voltage acceleration voltage applied to the display panel 100, and a video input. A video signal processing circuit 8 which performs predetermined signal processing so that the display panel 100 can display the video signal input from the terminal 7, and the scan driver 2 and the data driver based on the input video signal. It is comprised including the timing controller 9 as a control circuit which performs control of (4).

The video signal input to the video signal terminal 7 is first input to the video signal processing circuit 8. The video signal processing circuit 8 converts the format of the number of pixels of the signal, the frequency of the synchronization signal, and the like so that the input video signal can be displayed on the display panel 100 in which the thin film type electron emission elements are arranged in a matrix. Is done. The video signal format-converted by the video signal processing circuit 8 is input to the timing controller 9. The timing controller 9 generates the scan control signal Sscan which is a timing signal based on the input synchronization signal, and outputs this scan control signal Sscan to the scan driver 2. The scan control signal Sscan is a timing signal for controlling the scan driver 2 to select and scan a plurality of scan lines described later one by one. In addition, the timing controller 9 rearranges the data of the input video signal in synchronization with the generation of the scan control signal Sscan and outputs the data to the data driver 4. Then, an image is displayed on the display panel 100 through the data driver 4 and the scan driver 2.

The display panel 100 is a passive matrix type video display panel and has a rear substrate (not shown) and a front substrate (not shown) that face each other. That is, the back substrate (also referred to as cathode substrate) and the front substrate (also referred to as anode substrate) are held at predetermined intervals by a spacer (not shown) in a vacuum atmosphere container, for example, at a predetermined temperature, for example, frit glass (not shown). And the like). In the back substrate, a plurality of data lines 32 extending in a column direction (screen vertical direction) are arranged in a row direction (screen horizontal direction), and a plurality of scanning lines 31 extending in a row direction are arranged in a column direction. have. Further, a thin film type electron emission element (hereinafter simply referred to as an "electron emission element") 1 is provided at each intersection of the plurality of data lines and the plurality of scan lines. In this manner, the plurality of thin film electron-emitting devices 1 are arranged in a matrix on the back substrate. On the front substrate facing the rear substrate, a phosphor (not shown) is disposed at a position facing each thin film type electron-emitting device, and a metal which covers the phosphor to form an anode electrode to which an acceleration voltage is applied. A bag (not shown) is provided.

The scan driver 2 is connected to the scan line 31 of the display panel 100. The scan driver 2 outputs a selection signal (scan signal) for selecting the plurality of thin film-type electron emission devices 1 in units of rows based on the scan control signal Sscan which is a timing signal from the timing controller 8. . These selection signals are sequentially applied to the scanning lines in the column direction, and row selection operations are subsequently performed. As a result, the scanning lines are sequentially scanned in the column direction.

In addition, a data driver 4 is connected to the data line 32 of the display panel 100. Video data output from the timing controller 8 is supplied to the data driver 4. In response to the row selection by the scan driver 2, the data driver 4 supplies a drive signal based on the video data to the thin film type electron emission device in one row via the data line 32. The data driver 32 is provided with a data signal. Further, the data driver 4 maintains one row of data of the display panel 100, that is, one line of video data from the timing controller, for one horizontal period based on the timing signal from the timing controller 8, Rewrite the data every one horizontal period.

In addition, the anode line 34 of the display panel 100 includes a high voltage generation circuit 6 that generates an acceleration voltage of, for example, about 7 × 10 ³ V to accelerate electrons from the thin film type electron emission element 1. Is connected. Electrons emitted from the thin film type electron emission element 1 are accelerated from the rear substrate side to the front substrate side by an acceleration voltage applied to the metal back of the front substrate (not shown) via the anode line 34.

The operation according to the display in the display device constructed as described above will be described below.

When a drive signal is provided from the data driver 4 through the data line 32 to the electron emission element 1 in one row to which the selection signal is applied through the scan line 31 by the scan driver 2, The electron emission elements in the row emit positive electrons in accordance with the potential difference Vd between the selection signal and the drive signal. Since the level of the selection signal applied at the time of selection is constant irrespective of the position of the electron emission element, the amount of electron emission from the electron emission element is changed by the level of the drive signal. That is, the electron emission amount is determined by the level of the video signal that is the basis of the drive signal. An acceleration voltage (for example, about 7 × 10 ³ V) from the high voltage generation circuit 6 is applied to the anode line 34 of the display panel 100. For this reason, the electrons emitted from the electron emission element are accelerated by this acceleration voltage and collide with the phosphor arranged on the front substrate of the display panel 100. The phosphor is excited by the collision of the accelerated electrons and emits light. As a result, an image of the selected one horizontal line is displayed. In addition, the scan driver 2 selects electron emission elements one by one by sequentially applying a selection signal to the plurality of scan lines in the column direction. As a result, an image of one frame can be formed on the display surface of the display panel 100.

FIG. 1A is a plan view showing one pixel of the thin film type electron emission element array in the display panel 100 described with reference to FIG. 2. FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. 1A to illustrate the thin film type electron emission device in a cross section cut through the electron emission portion of the thin film type electron emission device 1 in the scanning line direction. It is a block diagram. FIG. 1C is a cross-sectional view taken along line BB ′ of FIG. 1A, and the thin film type electron emission device in a cross section cut through the electron emission portion of the thin film type electron emission device 1 in the data line direction. The configuration diagram. Note that one pixel (also referred to as a pixel) referred to herein is a unit pixel of color display, and each pixel is composed of a plurality of sub pixels (also referred to as subpixels) that display different primary colors.

In Fig. 1, on the insulating back substrate (cathode substrate) 10 such as glass, for example, the lower electrode 11 serving as a data line of, for example, an Al (aluminum) -Nd (neodymium) alloy is about 300, for example. It is formed in a stripe shape in the data line direction with a film thickness of 10 x ⁹ m. On the lower electrode 11, for example, Al ₂ O ₃ protective insulating film 14 which prevents concentration of an electric field at the edge of the lower electrode 11 and restricts or defines an electron emission portion for emitting electrons. (E.g., about 140 x 10 ^-9 m in thickness) and an insulating film 12 (e.g., about 10 x 10 ^-9 m in thickness) of Al ₂ O ₃ , which is an electron acceleration layer, have. As can be clearly seen from the plan view of Fig. 1A, the insulating film 12 has a substantially rectangular shape as viewed from the top surface.

The upper portion of the protective insulating film 14 avoids the electron emission electrode portion 131 (approximately rectangular shape, which will be described later in detail) that emits electrons reaching the upper portion of the insulating film 12, for example, to protect the silicon nitride film SiN. The insulating film 15 (for example, film thickness of about 100 x 10 ^-9 m) is formed. When there is a pinhole in the protective insulating film 14 formed by anodizing, the protective insulating film 15 fills the defect, and insulates the insulation between the lower electrode 11 and the upper bus electrode (to be described later) 20. It plays a role.

Further, on the protective insulating film 15 on the data line side (upper side of the page of FIG. 1A and the right side of the page of FIG. 1C), the electron emission electrode portion 131, which will be described later, is extended to extend in the scanning line direction. A stripe upper bus electrode 20 is formed.

The upper bus electrode 20 forms a laminated structure consisting of, for example, the metal film lower layer 16 and the metal film upper layer 18, and constitutes a part of the scan line. As the metal film lower layer 16, various metal materials, such as Cu (copper) and Cr (chromium), can be used as the Al-Nd alloy and the metal film upper layer 18, for example. Here, Al-Nd alloy is used for the metal film lower layer 16 and Cu is used for the metal film upper layer 18. In FIG. 1C, the lower metal layer 16 of the upper bus electrode 20 is separated from the upper metal layer 18 on the left side to ensure connection with the upper electrode 13. It is out. In addition, the lower metal film layer 16 is receding from the upper metal film layer 18 on the opposite side (the right side in FIG. 1C), and the upper metal film layer 18 is shaded.

On the insulating film 12, the upper electrode 13 which becomes an electrode part (electron emission electrode part) which emits an electron, for example, has a low layer of Ir (iridium) with good heat resistance, an intermediate layer of Pt (platinum), and an electron emission efficiency It is formed by, for example, sputtering by using a three-layer metal film having this good Au (gold) as an upper layer. The film thickness is, for example, suitably from about 4 × 10 ^-9 m ~ of about 8 × 10 ^-9 m and, here, for example, from about 6 × 10 ^-9 m. In addition, the said film thickness is not limited to this. At this time, the three-layer metal film constituting the upper electrode 13 is also sputtered on the upper surface of the upper bus electrode 20, the exposed metal film lower layer 16, and the protective insulating film 15. However, the upper electrode 13 is cut and formed into a film by the shading of the upper metal film 18 on one side of the adjacent stripe upper bus electrode 20 (right side of FIG. 1C). , Pixel by pixel. On the other hand, on the other side of the stripe-shaped upper bus electrode 20 (left side of FIG. 1C), the lower electrode 16 prevents the upper electrode 13 from disconnecting, and the protective insulating film 15 ) And the insulating layer 12 are continuously formed to form a feeding structure to the electron-emitting device.

The area of the electron emission electrode part 131 which is an electrode part which discharges an electron among the upper electrodes 13 is restrict | limited by the protective insulating film 14, and becomes the part corresponding to the upper part of the insulating film 12 substantially. Here, for the sake of the following description, the portion of the upper electrode 13 on the side of the substantially inverted quadrangular rod having the substantially flat electron emitting electrode portion (electron emitting portion) 131 as the bottom face the electron emission peripheral portion 132. In addition, the part which the electron emission part 131 and the electron emission peripheral part 132 form in the upper electrode 13 is called the upper electrode 130 especially. In the electron emission peripheral portion 132, the portion of the upper bus electrode 20 side is referred to as the electron emission peripheral portion 132a. In addition, the upper electrode 13 between the tip 16a of the electron emission electrode portion 131 side of the metal film lower layer 16 and the electron emission electrode portion 131 has an upper bus electrode 20 and an electron emission electrode portion. It functions as a connection part (contact part) 135 with 131, and comprises the feed path which feeds the electron emission electrode part 131 from the upper bus electrode 20. As shown in FIG.

The upper electrode 130 has a taper between the electron emission electrode portion (electron emission portion) 131 and the electron emission peripheral portion 132. In particular, the electron emission peripheral portion 132a is part of a feed path connecting the upper bus electrode 20 and the electron emission electrode portion 131. Therefore, in the taper rising part 133 from the electron emission electrode part 131 of the said electron emission peripheral part 132a, the electric field concentrates when the drive voltage Vd is applied between the lower electrode 11 and the upper electrode 13. This happens.

On the other hand, conventionally, ailization occurs in the upper electrode 13 by heat treatment, and the film thickness of the upper electrode 13 is reconstructed thinner, and the resistance value (sheet resistance) has increased. For this reason, due to the overlapping action of the resistance increase and the electric field concentration, the electron emission peripheral portion 132 tends to be disconnected at the tapered rising portion 133 from the electron emission electrode portion 131, resulting in a problem of low reliability. .

Therefore, in the present embodiment, in order to improve the reliability, as shown in FIGS. 1B and 1C, the portion of the electron emission electrode portion (electron emission portion) 131 is ailized. On the basis of the heat treatment causing the ions, a composite material is formed by melting a plurality of dissimilar metals (here, Ir, Pt, Au). That is, the plurality of dissimilar metals are melted to generate a composition change, thereby constructing a composite of the plurality of dissimilar metals in the electron emitting portion. Then, the film thickness is made thinner than other portions on the upper electrode 13, and in particular, than the portions in contact with the protective insulating films 14 and 15 around the electron emitting electrode portion (electron emitting portion) 131. In addition to being thin, the upper electrode 13 except for the substantially rectangular electron emission electrode portion 131 is not caused to ailize. In this manner, in the tapered upward portion 133 from the electron emission electrode portion 131, thinning due to ailization does not occur and the formed film thickness is almost maintained, so that the resistance (sheet resistance) value does not increase. Therefore, disconnection can be suppressed and reliability is improved.

In addition, since the film thickness of the upper electrode 13 does not become thin on the upper bus electrode 20, on the contact portion 135, and the electron emission peripheral portion 132, an increase in the resistance (sheet resistance) value is suppressed. This can reduce the effective driving voltage Vd and improve the electron emission efficiency as compared with the related art. Therefore, in the image display device to which the thin film type electron emission element (electron source) according to the present embodiment is applied, a bright image is obtained.

In addition, below, for the convenience of description, in the structure of the electron emission element of FIG. 1, the electron emission element of the state in which the electron emission electrode part 131 is not thinned shall be called an electron emission element before thinning. This thin film electron emission element can be formed even if it uses the technique of patent document 1, for example.

Next, with reference to FIG. 3, the laser system which thins only the electron emission electrode part 131 by laser irradiation is demonstrated.

In Figure 3,

(1) The back substrate (cathode substrate) which mounts the electron emission element before thin film of the structure of FIG. 1 is created (step S1).

(2) Only the electron-emitting electrode portion (electron-emitting portion) 131 is irradiated with a laser to perform local heating, and the ailization is performed by heating the Ir / Pt / Au 3-layer laminated film. In the present embodiment, as a laser, for example, using a YAG laser (YAG: Yittrium, aluminum, Garnet, Garnet), for example, power 2W / cm 2, wavelength? = 355 nm (355) X 10 ^-9 m). By laser processing, only the electron emission electrode part 131 can be ailated, and only the electron emission electrode part 131 can be thinned. By the local heating by laser processing, in the electron emission electrode portion (electron emission portion) 131, the three-layer laminated film of Ir / Pt / Au is composed of gold (Au), platinum (Pt), and iridium (Ir). It becomes thin, changing into the film | membrane of the composite of the trimetals which melted and mixed. That is, the three metals are melted to generate a composition change, and the electron-emitting electrode portion 131 forms a composite of the three metals. The film thickness in the electron emission electrode portion 131 is 2 to 4 nm, which is approximately half in terms of electron emission efficiency, for example, when 4 to 8 nm is used as the film thickness of the three-layer laminated film of Ir / Pt / Au. It is preferable to carry out (step S2).

(3) The back substrate (cathode substrate) equipped with the electron emission element (electron source) after thinning laser-processed in step S2, and the front substrate on which the fluorescent substance or the metal back were formed are shown at predetermined intervals using the spacer which is not shown in figure. It hold | maintains in the panel container which has not been made (step S3).

(4) Subsequent to the assembly of step S3, for example, panel sealing is performed using frit glass (step S4). At this time, the temperature with panel sealing is set to the temperature at which the three-layer laminated film of Ir / Pt / Au of the upper electrodes 13 and 130 does not cause ailization. Since ailization occurs when it exceeds 400 degreeC, it is preferable to set it as 400 degrees C or less. In addition, Japanese Patent Laid-Open No. 2001-243901 discloses that 410 ° C is used for heat treatment of islanding.

(5) When the sealing in step S4 is complete | finished, vacuum exhaust is performed in order to make the inside of a panel container into a vacuum atmosphere (step S5).

Through the above process, a panel is completed. In addition, in said process, step S1 and step S3-step S5 can use a prior art except the sealing adhesion temperature.

As described above, since the electron source in which only the electron-emitting electrode portion is thinned using laser processing is formed, and then the panel is sealed using the sealing adhesion temperature which does not cause the ailization, the electron-emitting electrode portion In the upper electrodes 13 and 130 except for 131, thinning due to reconstruction is unlikely to occur.

FIG. 4 is a diagram for explaining the effect of the thin film type electron emitting device of FIG. 1, which schematically shows the diode current Id (input and output characteristics) flowing between the electrodes of the thin film type electron emitting device. As can be clearly seen from the input / output characteristics of FIG. 4, the diode characteristic CD104 of the thin film type electron emission element has a lowered diode current Id to some extent compared to the characteristic CD101 before the laser processing, but after the conventional heating treatment It is greatly improved than the characteristic CD102. Therefore, the increase in the resistance value (sheet resistance) of the upper electrode except for the electron emission electrode portion 131 is reduced, and as a result, the disconnection occurring in the tapered rising portion 133 from the electron emission electrode portion 131 is obtained. Concerns are reduced and reliability is improved. At the same time, the reduction of the effective driving voltage Vd is also suppressed, and the electron emission efficiency is improved as compared with the prior art. As a result, when the thin film type electron emission element (electron source) according to the present embodiment is applied to a display device, an image display device technology capable of displaying a brighter image can be provided.

The thinning of the electron emission electrode portion of the upper electrode in the thin film type electron emission device according to the present embodiment can be performed not only by the laser processing but also by ion attack by rare gas.

Hereinafter, the example of thinning by ion attack is demonstrated using FIG. 1, FIG. 5, and FIG. Fig. 5 is a schematic diagram illustrating the action of thinning due to ion attack, and Fig. 6 is a view illustrating a process of forming an electron emission electrode portion of the upper electrode of the thin film type electron emission element according to the present embodiment. 5, only the vicinity of the upper electrode 130 which consists of the electron emission electrode part 131 and the electron emission peripheral part 132 is shown for convenience.

In Figure 6,

(1) First, a back substrate (cathode substrate) on which the electron-emitting device before thinning of the structure of FIG. 1 is mounted is created (step S11).

(2) The back substrate (cathode substrate) on which the electron emission element (electron source) is mounted before the thin film and the front substrate on which the phosphor or the metal back is formed are separated by a predetermined interval (for example, 1 ×) using a spacer (not shown). It is hold | maintained in the panel container which is not shown in ^10-3 m-3 * 10 <^-3> m) (step S12).

(3) Subsequent to the assembly of step S12, for example, panel sealing is performed using frit glass (step S13). At this time, the temperature with panel sealing is set to the temperature (for example, 400 degrees C or less) which Ir / Pt / Au three-layer laminated film does not cause ailization.

(4) Next, rare gases, such as Ne (neon), Ar (argon), and Xe (xenon), are introduced into a panel container (step S14). Here, although Ar is easy to obtain, it is not limited to this. And the inside of a panel container is depressurized to the pressure (for example, 0.2-0.8 Pa) which a rare gas is easy to ionize.

(5) After that, the FED panel is driven to age for a predetermined time (step S15). When the FED panel is driven, electrons e ⁻ are emitted from the electron emission electrode portion 131 of the upper electrode 130 as shown in FIG. 5. The electron e ⁻ emitted from the electron emission electrode portion 131 is accelerated toward the metal back, which is an anode electrode (not shown) to which an acceleration voltage (for example, about 7 × 10 ⁻³ V) is applied, but part of It collides with Ar of the rare gas existing in the panel to ionize Ar. The ionized Ar ⁺ is pulled close to the electron emission electrode portion 131 side of the back substrate (cathode substrate), causing a slight sputtering phenomenon with respect to the electron emission electrode portion 131. Thereby, the electron emission electrode part 131 is heated, and by this heating, the three-layer laminated film of Ir / Pt / Au of the electron emission electrode part 131 is ailated, and thinning occurs. In the electron emission electrode portion (electron emission portion) 131, the three-layer laminated film of Ir / Pt / Au is melted and mixed with gold (Au), platinum (Pt), and iridium (Ir) by the heating. It is thinned while changing to the film | membrane of the said trimetallic composite. That is, the said three metals are melted and a composition change is produced, and the compound of the said three metals is comprised in the electron emission part. Of course, at this time, the ionized Ar ⁺ is also attracted to the upper electrode 130 other than the electron emission electrode portion 131. However, the opposing interval between the upper electrode and the metal back is, for example, about 1 × 10 ⁻³ m to 3 × 10 ⁻³ m, and the electric field therebetween becomes a substantially parallel electric field. Therefore, since Ar on the electron beam trajectory from the electron emission electrode part 131 is ionized, the ratio attracted to the electron emission part 131 is large. Therefore, concentration of ailization of the electron emission electrode portion 131 occurs, and ailization hardly occurs at the upper electrodes other than the electron emission electrode portion 131. That is, in the upper electrodes other than the electron emission electrode portion 131, the increase in the resistance value (sheet resistance) due to thinning is suppressed, and there is a fear of disconnection at the tapered riser 133 from the electron emission electrode portion 131. It is reduced and the reliability is improved.

(6) After aging in step S15, vacuum evacuation is performed to bring the inside of the panel container into a vacuum atmosphere (step S16).

Through the above process, a panel is completed. In the said process, the prior art can be used for step S11, step S13, and step S16 except sealing temperature.

As described above, even by the ion attack method, only the electron emission electrode portion of the upper electrode of the thin film type electron emission element can be thinned, and the reliability can be improved. At the same time, the reduction of the effective driving voltage Vd can also be suppressed, and the electron emission efficiency can be improved as compared with the prior art. As a result, when the thin film type electron emission element (electron source) according to the present embodiment is applied to a display device, a brighter image can be displayed.

According to the present invention, the electron emission efficiency and reliability of the thin-film electron-emitting device can be improved. As a result, it becomes possible to provide an image display technology with improved screen brightness and reliability.

Claims (10)

a) a thin film type electron emission device composed by sequentially laminating a lower electrode, an insulating layer and an upper electrode, b) a back substrate having the thin film-type electron emission devices arranged in a plurality of matrix shapes, and c) a front substrate provided opposite the rear substrate, and having a phosphor arranged to emit light by electrons from the thin-film electron-emitting device; A display panel having a A driving circuit for driving the display panel to emit electrons to the thin film type electron emission element provided in the display panel; A control circuit for controlling the driving circuit based on an image signal Including; An image in which the electron emitting portion of the upper electrode of the thin film type electron emitting element is composed of a composite obtained by melting of a plurality of dissimilar metals, and the thickness of the electron emitting portion of the upper electrode is thinner than the thickness of the other portion of the upper electrode. Display device. The method of claim 1, An image display in which the thickness of the electron emission portion of the upper electrode of the thin film type electron emission element is thinner than the thickness of the portion of the upper electrode in contact with the protective insulating layer for regulating electron emission disposed around the electron emission portion. Device. The method of claim 1, The upper electrode of the thin film type electron emission element is made of iridium, platinum and gold, and the electron emission portion is a composite of the three metals. The method of claim 1, And an electron emission portion of the upper electrode of the thin film type electron emission element is thinned by local heating. The method of claim 1, And an electron emission portion of the upper electrode of the thin film type electron emission element is thinned by ion bombardment of electrons and rare gas emitted from the thin film type electron emission element. The method of claim 1, And the thickness of the electron emission portion of the upper electrode of the thin film type electron emission element is about 2 × 10 ^-9 m to about 4 × 10 ^-9 m. The method of claim 1, An image display apparatus, wherein the sheet resistance at the electron emission portion of the upper electrode is higher than the sheet resistance at another portion of the upper electrode. A thin film type electron emission device configured by sequentially stacking a lower electrode, an insulating layer, and an upper electrode, A back substrate having the thin film-type electron emission devices arranged in a plurality of matrix shapes, and The front substrate which is provided to face the back substrate, and has a phosphor arranged to emit light by electrons from the thin film type electron emission element. Including; A display in which the electron emission portion of the upper electrode of the thin film type electron emission element is composed of a composite obtained by melting of a plurality of dissimilar metals, and the thickness of the electron emission portion of the upper electrode is thinner than the thickness at other portions of the upper electrode. panel. The method of claim 8, A display panel in which the sheet resistance at the electron emission portion of the upper electrode is higher than the sheet resistance at other portions of the upper electrode. The method of claim 8, And the upper electrode is composed of iridium, platinum, and gold, and the electron emission portion is a composite of the three metals.

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