JP4235058B2 - Manufacturing method of display device - Google Patents

Description

  The present invention relates to a method for manufacturing a display device having a field emission cathode.

  Conventional field emission cathodes include surface conduction emitters or carbon nanotube emitters in addition to Spindt emitters, silicon emitters, and transistor structure emitters. These field emission displays have a large number of pixels (field emission cathodes and phosphors opposed thereto). For example, high-definition displays have 6 million or more pixels.

  However, in a normal manufacturing process, it is difficult to completely manufacture all of a large number of pixels, and in order to use as a display, it is necessary to repair defects by some method.

  Further, in order to stably generate electrons from the field emission cathode, the internal space of the display (hereinafter, simply referred to as the inside of the panel) is present on the surface of the cathode when evacuated and sealed. It is necessary to remove deposits.

  Furthermore, among various field emission cathodes, field emission cathodes using carbon-based materials such as carbon nanotubes, which have recently attracted attention, are stable operation in a low vacuum environment, electron emission characteristics in a low electric field, and high current. Since the density can be expected, it is attractive as a cathode material for a field emission cathode display. However, these carbon-based materials have a problem that their characteristics change depending on the use environment, and it is necessary to find a prescription for sufficiently exhibiting excellent characteristics.

  In the prior art, the following processing is performed for pixel defects. For example, with respect to the so-called singular point where the electron emission is abnormally low compared to other standard pixels and it always lights when operated as a display, this pixel can be turned off using means such as a laser. The process which ends is common. However, this process is relatively complicated. That is, first, it is necessary to search for a singular point from a large number of pixels, and it is indispensable to select only the singular point and turn it off, which requires a lot of labor.

  Next, in order to remove the deposits adhering to the field emission cathode, the inside of the panel is usually evacuated under reduced pressure. At this time, the inside of the panel is evacuated while the whole panel is heated to a high temperature so that the deposits are easily detached from the field emission cathode. However, in some cases, the deposit cannot be evacuated under heating. In addition, when a process is performed in a high-temperature environment, depending on the material of the field emission cathode, the property changes due to oxidation or the like, and there is a danger that the electron emission characteristics deteriorate.

Further, as a conventional technique, a method of irradiating a field emission cathode with a laser, an electron beam, an ion or the like has been proposed as a method for uniformizing electron emission characteristics from a carbon-based field emission cathode (for example, Patent Document 1). And Patent Document 2). However, in these methods, when the display device is enlarged and the area of the field emission electrode is increased, it takes a considerable time to scan the field emission cathode over a wide area with a laser or an electron beam. It cannot be denied that the efficiency of the system is lowered. Accordingly, there is a demand for the development of a new means that can quickly process the uniform field emission of the field emission cathode.
JP 2000-22305 A JP 2001-180920 A

  The present invention has been made in order to solve the above-described problems, and efficiently discharges defective pixels which are singular points in a display, and does not deteriorate discharge characteristics from a field emission cathode. Further, the present invention provides a method for manufacturing a display device that can sufficiently remove attachments from the substrate and further improve the uniformity of electron emission even in the case of a large field emission display.

A method of manufacturing a display device according to the present invention is a method of manufacturing a display device having an internal space including a field emission cathode that emits electrons by an applied electric field and an anode that faces the field emission cathode and captures the electrons. Wherein the internal space is evacuated and then a rare gas is introduced into the internal space so that a gas discharge is generated between the anode and the anode only at the singular point where the electron emission of the field emission cathode is likely to occur. After the gas discharge is generated by controlling the gas, the rare gas is exhausted from the internal space, the rare gas is again introduced into the internal space, and the gas is discharged between the anode and the anode in the entire range of the field emission cathode. After the discharge is generated, the internal space is again evacuated and sealed.
The gas discharge is preferably a discharge generated at a discharge current density of 100 μA / cm ² or less.

  This method makes it easy to emit electrons from the field emission cathode, and improves the uniformity of electron emission.

In addition, this method can efficiently treat the deterioration of the field emission cathode corresponding to the singular point where electron emission is extremely likely to occur and the vacuum sealing.

Further, by this method, after the electron emission characteristics are made uniform, the entire range of the field emission cathode can be further made uniform without bringing the field emission cathode into contact with the atmosphere.

In addition, this method can efficiently perform discharge treatment at one place in the entire range of the field emission cathode, discharge treatment in the entire range of the field emission cathode, and vacuum sealing.

In addition, even when there are a plurality of singular points where electron emission is extremely likely to occur , this method makes it possible to efficiently deal with uniform electron emission characteristics.

  The present invention makes it easy to emit electrons from the field emission cathode and improves the uniformity of electron emission by generating a gas discharge between the field emission cathode and the anode before vacuum-sealing the internal space. It is possible to provide a method for manufacturing a display device having an effect that it can be performed.

  Embodiments of the present invention will be described below with reference to the drawings.

  1A, the display device 10 according to the present embodiment includes a front plate 20 having a transparent electrode 22 and a phosphor screen 23 formed on a glass substrate 21, a cathode bus 32 on a glass substrate 31, The field emission cathode 33, the insulating layer 34, and the back plate 30 on which the gate electrode 35 is formed are joined to face each other through a spacer 40. The inside of the panel surrounded by the front plate 20, the back plate 30 and the spacer 40 is sealed so that gas does not pass through, and the inside of the panel can be sealed in a vacuum.

  A single gas composed of a rare gas such as He, Ne, Ar, Kr, or Xe or a mixed gas obtained by mixing two or more of these is sealed in the panel. As an example, when the gas pressure is 50 Torr, a mixed gas of 90% He and 10% Xe is sealed. In this panel, there are a transparent electrode 22 on the front plate 20, a gate electrode 35 on the back plate 30, and a field emission cathode 33 connected to the cathode bus 32 as electrodes. As an electrode for generating a discharge with the field emission cathode 33, the transparent electrode 22 farthest from the field emission cathode 33 is used.

The voltage causing discharge is applied with the transparent electrode 22 as the positive electrode and the cathode bus 32 connected to the field emission cathode 33 as the negative electrode. In this case, as shown in FIG. 1B, the range of discharge covers the entire range (area S) where the field emission cathode 33 exists, the discharge current is i (μA), and the area of the discharge range is S ( cm ² ), the discharge current density J is expressed by the following equation.

J = i / S (μA / cm ² )
When the value of the discharge current density J is 100 μA / cm ² or less, uniformization can be achieved efficiently. In FIG. 1B, the area S of the discharge range is the sum of the areas of the field emission cathodes 33.

  Next, an exhaust process of the panel of the display device of the present embodiment will be described with reference to FIG.

  First, the front plate 20 and the back plate 30 are exhausted through the exhaust pipe 50 provided on the back plate 30 side of the display device 10 in which the front plate 20 and the back plate 30 are sealed through the spacer 40 (FIG. 2A). At this time, it is desirable to evacuate while heating at 350 ° C. or higher in order to remove deposits adhered to the panel.

  Subsequently, a discharge gas for causing discharge at only one place is introduced from the exhaust pipe 50 (FIG. 2B). Then, between the cathode bus 32 connected to the field emission cathode 33 and the transparent electrode 22, gas discharge is performed at a single discharge point 60 with the transparent electrode 22 as a positive electrode and the cathode bus 32 as a negative electrode (FIG. 2 ( c)).

  When there is a singular point, discharge starts from the field emission cathode 33 where electrons are most likely to be emitted. Therefore, discharge is performed only at the singular point where electron emission is most likely to occur by adjusting and controlling the discharge current. It becomes possible. If the discharge current in this case is 50 μA or more, the discharge is stable and effective. The discharge is stopped when the characteristics of the field emission cathode 33 in which the one-point discharge has occurred deteriorated due to sputtering or the like. When there are a plurality of singular points, the same discharge is generated continuously.

  Subsequently, the gas in the panel is exhausted from the exhaust pipe 50 of the panel (FIG. 2D). Further, in order to cause the entire surface discharge, a gas introduction process for reintroducing gas through the exhaust pipe 50 is performed (FIG. 2 (e)). Then, between the cathode bus 32 and the transparent electrode 22 to which the field emission cathode 33 is connected, the transparent electrode is used as a positive electrode and the cathode bus is used as a negative electrode. 2 (f)).

  Even when the surface of the field emission cathode 33 is oxidized when the panel is heated in the process of FIG. 2A, the surface of the field emission cathode 33 is exposed to a clean surface by sputtering in the process of FIG. It becomes possible to do. When the characteristics of the entire surface are almost the same, the discharge is stopped and the gas in the panel is exhausted through the exhaust pipe 50 (FIG. 2 (g)).

  The processes of FIGS. 2A to 2G show an example of an exhaust process using discharge forming, but the type of gas that causes one-point discharge and full-surface discharge is appropriate. If the gas pressure is the same (for example, the same type), the two steps of FIGS. 2D and 2E can be omitted.

  Further, when there is no singular point that easily causes electron emission in each field emission cathode 33 in the panel, it is not necessary to generate a one-point discharge, so that FIG. 2 (b), FIG. 2 (c) and FIG. The process of FIG. 2D can be omitted.

  Further, when the electron emission characteristics of each field emission cathode 33 in the panel are substantially uniform except for the singular point, it is sufficient to turn off only the singular point. Steps (e) and (f) can be omitted.

  As described above, the method for manufacturing a display device according to the present invention has the effect of facilitating the emission of electrons from the field emission cathode and the improvement of the uniformity of electron emission, and includes the field emission cathode. It is useful as a display device.

(1) Side sectional view of a display device showing a method for manufacturing a display device according to an embodiment of the present invention (2) Plane sectional view of a display device showing a method for manufacturing a display device according to an embodiment of the present invention Process drawing of the manufacturing method of the display apparatus of embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display apparatus 20 Front plate 21 Glass substrate 22 Transparent electrode 23 Fluorescent screen 30 Back plate 31 Glass substrate 32 Cathode bus 33 Field emission cathode 34 Insulating layer 35 Gate electrode 40 Spacer 50 Exhaust tube 60 Discharge

Claims (2)

A method of manufacturing a display device having an internal space including a field emission cathode that emits electrons by an applied electric field and an anode that captures the electrons facing the field emission cathode, wherein the internal space is once evacuated. Then, a rare gas is introduced into the internal space, and the gas discharge is generated by controlling the electric field so that the gas discharge is generated between the anode and the anode only at the singular point where the electron emission of the field emission cathode is likely to occur. Then, the rare gas is exhausted from the internal space, the rare gas is again introduced into the internal space, and a gas discharge is generated between the anode and the anode in the entire range of the field emission cathode. A method for manufacturing a display device, characterized by sealing again by vacuuming. The method for manufacturing a display device according to claim 1, wherein the gas discharge is a discharge generated at a discharge current density of 100 μA / cm ² or less.

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