JP3938185B2 - Image display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an image display device and a manufacturing method thereof. More specifically, an image display device in which a rear plate including a plurality of electron-emitting devices and a face plate including a phosphor that displays an image by irradiation of electrons from the electron-emitting devices are arranged to face each other, and its manufacture Regarding the method.

  Conventionally, a rear plate provided with a plurality of electron-emitting devices in which a conductive film having an electron-emitting portion is provided between a pair of device electrodes, and a phosphor that displays an image by irradiation of an electron beam from the electron-emitting device Also known is an image display device in which a face plate provided with a metal back provided on the surface of the phosphor is opposed and sealed (see, for example, Patent Document 1).

On the other hand, as a method for manufacturing an image display device, a baking process for discharging impurity gas contained in a face plate provided with a phosphor and a rear plate provided with an electron-emitting device is performed, and the baking process is performed. A first getter process is performed on one or both of the face plate and the rear plate, and a film of a getter material such as barium is deposited to a thickness of 5 to 500 nm, and then an electron beam irradiation process is performed to remove impurity gas. Further, a second getter treatment is applied to one or both of the face plate and the rear plate, and a film of a getter material such as barium is again attached to a thickness of 5 to 500 nm, and then the face plate and the rear plate The method of creating a high vacuum of 10 ⁻⁶ Pa or higher in the obtained image display device by sealing the surfaces of It is known to perform the processing in the order of processing, first getter processing, sealing, and the like (for example, see Patent Document 2).

JP 2000-251621 A JP 2001-229828 A

  However, the conventional image display device described in Patent Document 1 has a problem in that fluctuations appear in currents emitted from individual electron-emitting devices when image display is performed for a long time such as several thousand hours. In addition, in the case of the conventional manufacturing method described in Patent Document 2, it is indispensable to form the coating film of the getter material with a thickness that functions as a getter. In the case of an image forming apparatus in which the film of the getter material having such a thickness is formed even on the electron emission element of the rear plate, the reactive current that does not function as an electron emission element or does not contribute to electron emission increases. There is a detrimental effect that the performance of the electron-emitting device is significantly deteriorated. Therefore, in reality, the getter material film is formed only on the face plate which does not cause such a problem, and it is not formed on the rear plate.

  By the way, the current fluctuation in the conventional image display apparatus is the case where all the electron-emitting devices existing in one image forming apparatus are uniformly changed, for example, uniformly increased or decreased uniformly. Although not particularly a problem, as a result of intensive studies by the present inventors, it has been found that the change varies depending on how each electron-emitting device is driven.

  Specifically, the emission current increases as the electron-emitting device has a longer driving time. Further, when the driving time is the same, the emission current increases as the electron-emitting device performs brighter display. That is, there is a tendency for the current increase to increase as the electron-emitting device has more emitted electrons.

  This change is the same brightness image over the entire screen, for example, when performing a white display all over, all the electron-emitting devices cause a similar increase in current, so only the whole is uniformly bright, In an image display device that normally requires an image display that changes from moment to moment, the uniformity of brightness is impaired.

  Furthermore, when a still image display is continued for a long time, such as an output screen of a computer, the bright image display portion becomes brighter due to an increase in emission current, and the black display portion remains unchanged. Therefore, the brightness distribution tends to be noticeable.

  The increase in current caused by the difference in the displayed image is not immediately eliminated even if different image displays are performed thereafter, and the so-called burn-in phenomenon that leaves the brightness distribution generated in the previous image display as it is. As a result, an image display device with significantly reduced uniformity is obtained.

  As a result of further detailed studies, the present inventors have found that the increase in the emission current is accompanied by an increase in electron emission efficiency as well as a change in the absolute value of the current.

  The electron emission efficiency here refers to the current that flows between the device electrodes when a constant voltage is applied between the device electrodes of the electron-emitting device (hereinafter referred to as “device current”), and is emitted from the electron-emitting portion into the vacuum. It is needless to say that an electron-emitting device having a small element current and a large emission current, that is, a high electron-emitting efficiency is preferable as an image display device. Yes.

  When the emission current is increased by the image display, the increase in the device current is not large compared with the increase in the emission current. As a result, the electron emission efficiency of the electron emission device itself is increased. Similar to the increase in current described above, this change becomes remarkable by driving for a longer time or brighter image display, and also causes a burn-in phenomenon.

  Both the increase in current and the increase in electron emission efficiency are factors that degrade the uniformity of the display image, and have been a major obstacle to realizing an image display device that is required to display an image with high quality over a long period of time.

  An object of this invention is to provide the image display apparatus which can maintain the uniformity of brightness over a long period of time.

  As a result of the present inventors diligently examining the cause of the increase in current and the increase in electron emission efficiency, on the electron-emitting device that caused the increase in current and the increase in electron emission efficiency in the image display device in which the metal back was exposed, The adhesion of the metal or metal compound material constituting the metal back was confirmed. It was also found that the metal or metal compound material did not adhere to the electron-emitting device corresponding to the portion where only the black image or the extremely dark image was continuously displayed.

  Therefore, when various metals or metal compounds are vapor-deposited on the electron-emitting device in a vacuum apparatus, when a generally-known low work function material is vapor-deposited, the emission current at the initial stage of driving increases and the initial efficiency increases. It was confirmed that it was expensive.

  From the above results, the performance and characteristics of the electron-emitting device are extremely sensitive to the material forming the electron-emitting portion or the state of the electron-emitting portion. It is considered that the characteristics of the electron-emitting device are changed by dropping (scattering) and adhering the constituent material of the metal back, which is exposed to face the device, onto the electron-emitting device. In addition, a getter material film may be formed on the surface of the metal back to create a high vacuum in the image display device. In this case, the exposed getter material falls and adheres onto the electron-emitting device. This is considered to change the characteristics of the electron-emitting device.

  The present invention has been made on the basis of the knowledge of the present inventors, and the first is an electron emission comprising a pair of electrodes and a conductive film having an electron emission portion disposed between the electrodes. A rear plate having a plurality of elements faces a phosphor that displays an image by irradiation of electrons from the electron-emitting device and a face plate that is exposed on the surface of the phosphor and that has a coating of a metal or a metal compound material. In the image display device arranged as described above, a film of the same metal or metal compound material as the metal or metal compound material constituting the film exposed on the surface of the phosphor is formed on the conductive films of the plurality of electron-emitting devices. The image display device is provided with a thickness of 0.2 nm to 4.5 nm.

  According to a second aspect of the present invention, a rear plate including a plurality of electron-emitting devices each including a pair of electrodes and a conductive film having an electron-emitting portion disposed between the electrodes; In the method of manufacturing an image display device in which a phosphor that displays an image by electron irradiation and a face plate that is exposed on the surface of the phosphor and that has a coating of a metal or a metal compound material are disposed opposite to each other, After forming a film of the same metal or metal compound material as the metal or metal compound material constituting the film exposed on the surface of the phosphor with a thickness of 0.2 nm to 4.5 nm on the conductive film of the emission element The present invention provides a method for manufacturing an image display device, wherein a rear plate and a face plate are sealed.

  According to the present invention, a metal or a metal compound that causes a drop and adhesion on a conductive film (conductive member) having an electron emission portion of an electron emission element due to image display for a long period of time and causes fluctuations in the characteristics of the electron emission element. Since the same metal or metal compound coating is provided on the conductive film (conductive member) of the electron-emitting device in advance, even if the metal or metal compound drops and adheres, the characteristic variation of the electron-emitting device is large. Can be prevented. Accordingly, it is possible to maintain image display with uniform brightness over a long period of time. Further, the metal or metal compound film is 0.2 nm to 4.5 nm and is thinner than the film of the getter material.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a partially cutaway perspective view showing an example of an image display device according to the present invention, and FIG. 2 is a schematic view showing a basic configuration example of an electron-emitting device used in the image display device of FIG. ) Is a cross-sectional view, and (b) is a plan view.

  As shown in FIG. 1, the rear plate 7 includes an electron source electron source substrate 1 provided with a large number of electron-emitting devices 8. As shown in FIG. 2, each electron-emitting device 8 has a pair of device electrodes 2 and 3 on the electron source substrate 1, and has an electron-emitting portion 5 across the device electrodes 2 and 3. A conductive film 4 is provided. Further, a metal or metal compound coating 6 is provided on a region adjacent to the electron emission portion 5, that is, on the conductive film 4 forming the electron emission portion 5 by a gap. This coating 6 will be described later.

  On the electron source substrate 1, Y-direction wiring (lower wiring) 9 is provided connected to one element electrode 3 of the electron-emitting device 8, and further, through an insulating layer (not shown), Y An X-direction wiring (upper wiring) 10 connected to the other element electrode 2 through a contact hole (not shown) provided in the insulating layer is provided in a direction crossing the directional wiring 9. These Y-direction wiring 9 and X-direction wiring 10 are desired to have a low resistance so that a substantially uniform voltage is supplied to the electron-emitting devices 8, and the material, film thickness, wiring width, etc. are appropriately set. The Further, as an example of a method for forming the Y-direction wiring 9, the X-direction wiring 10, and the insulating layer, a combination of a printing method, a sputtering method, and a photolithography technique can be used. Each electron-emitting device can be selectively driven by applying a voltage between the device electrodes 2 and 3 via the Y-direction wiring 9 and the X-direction wiring 10.

  Opposite to the rear plate 7 having the electron source substrate 1, a phosphor 12, a metal back 13, and the like are provided on the inner surface of a transparent insulating face plate 11 such as glass. Reference numeral 14 denotes a support frame, and the rear plate 7, the support frame 14, and the face plate 11 are sealed with frit glass or the like, and form a panel-like sealed container.

  The space surrounded by the rear plate 7, the support frame 14, and the face plate 11 is a vacuum atmosphere. This vacuum atmosphere can also be formed by providing an exhaust pipe on the rear plate 7 or the face plate 11 and evacuating the inside, and then sealing the exhaust pipe. The formation of a vacuum atmosphere can be facilitated by sealing the rear plate 7 and the face plate 11 in a vacuum chamber.

  To display an image, a driving circuit for driving the electron-emitting device 8 is connected to the image display device, and a voltage is applied between the desired device electrodes 2 and 3 via the Y-direction wiring 9 and the X-direction wiring 10. Then, electrons are generated from the electron emission portion 5 (see FIG. 2), and a high voltage is applied from the high voltage terminal 15 to the metal back 13 which is the anode electrode to accelerate the electron beam and collide with the phosphor 12. It can be carried out. In addition, by installing a support body (not shown) called a spacer between the face plate 11 and the rear plate 7, a large-area panel-shaped sealed container having sufficient strength against atmospheric pressure can be configured. .

  As clearly shown in FIG. 2, the electron-emitting device 8 provided with the conductive film 4 having the electron-emitting portion 5 across the pair of device electrodes 2 and 3 is referred to as a surface conduction electron-emitting device. Is. According to the basic characteristics of this surface conduction electron-emitting device, the emitted electrons from the electron-emitting portion 5 have a peak value and a width of a pulse voltage applied between the device electrodes 2 and 3 facing each other above a threshold voltage. Since the amount of current is also controlled by the intermediate value, halftone display is possible. Further, when a large number of electron-emitting devices 8 are arranged as in this example, for example, a selection line is determined by a scanning line signal sent to the Y-direction wiring 9, and an information signal is supplied to each X-direction wiring 10 to individually If a pulse voltage is appropriately applied to the electron-emitting device 8, a voltage can be appropriately applied to the arbitrary electron-emitting device 8, and the arbitrary electron-emitting device 8 can be turned on.

  Further, the configuration of the electron-emitting device 8 will be described.

As the electron source substrate 1, quartz glass, glass with reduced impurity content such as Na, blue plate glass, blue plate glass with a SiO ₂ film laminated by sputtering, ceramics such as alumina, Si substrate, etc. are used. Can do.

As a material of the pair of element electrodes 2 and 3, a general conductive material can be used. For example, from metals or alloys such as Ni, Cr, Au, Mo, W, Pt, Ti, A, Cu, Pd, metals or metal oxides such as Pd, Ag, Au, RuO ₂ , Pd—Ag, and glass It can be suitably selected from a configured printed conductor, a transparent conductor such as In ₂ O ₃ —SnO ₂ , and a semiconductor conductor material such as polysilicon.

  The distance between the device electrodes 2 and 3, the length of the device electrodes 2 and 3 (the length perpendicular to the opposing direction of the device electrodes 2 and 3), the shape of the conductive film 4, etc. Designed. The distance between the device electrodes 2 and 3 is preferably in the range of several hundred nm to several hundred μm, and more preferably in the range of several μm to several tens of mm in consideration of the voltage applied between the device electrodes 2 and 3. is there.

  The lengths of the device electrodes 2 and 3 are preferably in the range of several μm to several hundred μm in consideration of the resistance value of the electrodes and the electron emission characteristics. The film thickness of the device electrodes 2 and 3 is preferably in the range of several tens of nm to several μm.

  In the example shown in FIG. 2, the device electrodes 2 and 3 and the conductive film 4 are stacked in this order from the electron source substrate 1 side. However, the conductive film 4 and the device electrodes 2 and 3 are stacked in this order. It can also be set as the structure which carried out.

  In order to obtain good electron source characteristics, the conductive film 4 is particularly preferably a fine particle film composed of fine particles. The film thickness is appropriately selected depending on the step coverage between the device electrodes 2 and 3, the resistance value, the forming conditions described later, etc., but is preferably 5 nm to 50 nm.

In addition, the resistance value of the conductive film 4 is preferably a certain level in order to facilitate the forming process in a state before the forming process described later (a state before the formation of the electron emission portion 5). Specifically, it is preferably 10 ³ Ω / □ to 10 ⁷ Ω / □. On the other hand, the conductive film 4 after forming (after forming the electron emission portion 5) preferably has a low resistance so that a sufficient voltage can be applied to the electron emission portion 5 via the device electrodes 2 and 3. Therefore, the conductive film 4 is formed as a metal oxide thin film having a sheet resistance value of 10 ³ Ω / □ to 10 ⁷ Ω / □ or less, and is reduced after the forming process to form a metal film having a lower resistance. It is preferable to do. Therefore, the lower limit of the resistance value of the conductive film 4 in the final state is not particularly limited. Here, the resistance value of the conductive film 4 here means a sheet resistance value measured in a region not including the electron emission portion 5.

Examples of the material of the conductive film 4 include metals such as Pd, Pt, Ru, Ag, Au, oxides such as PdO, SnO ₂ , and In ₂ O ₃ , borides such as HfB ₂ , carbides such as TiC and SiC, Examples thereof include nitrides such as TiN, semiconductors such as Si and Ge, and carbon. As a formation method, various methods such as an ink jet coating method, a spin coating method, a dipping method, a vacuum deposition method, and a sputtering method can be applied.

  Among the materials of the conductive film 4, PdO can be easily formed into a thin film by baking an organic Pd compound in the air, and since it is a semiconductor, it has a relatively low electrical conductivity, and a film for obtaining a sheet resistance value in the above range. Wide thickness process margin, easy reduction after formation of the electron emission portion 5 to a metal Pd, it is easy to reduce the film resistance after the formation of the electron emission portion 5, and also increase the heat resistance Therefore, it is a suitable material.

  The electron emission portion 5 is a high-resistance crack (nano-fischer) portion formed in a part of the conductive film 4 by a forming process to be described later. The form of the electron emission portion 5 is the film thickness, film quality, material, and later described. It depends on a method such as energization forming.

  The forming process is performed by applying a voltage from an external power source in a vacuum atmosphere. By energizing between the device electrodes 2 and 3, the conductive film 4 is locally destroyed, deformed or altered, and a crack-like electron emission portion 5 in an electrically high resistance state is formed. The voltage to be applied generally uses a pulse waveform. As shown in FIG. 3A, when applying a pulse having a constant pulse peak value, as shown in FIG. 3B, the pulse peak value is applied. In some cases, the voltage is applied while increasing. In FIG. 3A, the pulse width T1 is usually about 1 μsec to 10 msec, the pulse interval T2 is usually about 10 μsec to 100 msec, and the peak value (peak voltage during forming) is appropriately selected according to the material of the conductive film 4 and the like. Is done. Further, the pulse width T1 and the pulse interval T2 in FIG. 3B are the same as those in FIG. 3A, and the crest value and the increase amount of the crest value are appropriately selected according to the material of the conductive film 4 and the like. .

  When a metal oxide is used as the conductive film 4, the electron emission portion 5 can be formed while reducing the conductive film 4 when energized and heated in an atmosphere containing a gas having a reducing property such as some hydrogen. . The conductive film 4 containing the metal oxide as a main component at the beginning becomes the conductive film 4 containing the metal as a main component after the forming is completed, and the parasitic resistance when driving the electron-emitting device can be reduced. it can. In addition, a process for completely reducing the conductive film 4 can be added.

  The end of the forming process is performed by inserting a voltage that does not cause local destruction or deformation of the conductive film 4 between the forming pulses, for example, a pulse voltage of about 0.1 V, and the device current (between the device electrodes 2 and 3). For example, when the resistance value is 1000 times or more of the resistance before the forming process.

  Next, an activation process for disposing a film mainly composed of carbon and / or a carbon compound (not shown in FIG. 2) on the conductive film 4 in the adjacent region of the electron emission portion 5 formed by the forming process. Will be described.

  The activation step is performed, for example, by introducing an appropriate carbon compound gas in a vacuum and applying a pulse voltage between the device electrodes 2 and 3. By performing the activation step, the emission current emitted from the vicinity of the electron emission portion 5 can be greatly increased.

  The preferable gas pressure of the carbon compound in the activation step varies depending on the use of the electron source substrate, the type of the carbon compound, and the like, and thus is appropriately set according to circumstances.

Suitable carbon compounds include alkanes, alkenes, alkyne aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, organic acids such as phenol, carvone, and sulfonic acid. Can be mentioned. Pressure carbon compound to be introduced, members that are used to shape or vacuum device of the vacuum apparatus, but is slightly affected by the kind of the carbon compound, for example, in the case of ^{tolunitrile, 1 × 10 -5 Pa~1 × 10} - ^{About 2} Pa is preferable.

  Electrons in which a film composed of carbon and / or a carbon compound is formed from the carbon compound present in the atmosphere by the forming step by applying a pulse voltage between the device electrodes 2 and 3 in the presence of the carbon compound. It is formed on the conductive film 4 in and around the discharge part 5.

  FIGS. 4A and 4B show preferred examples of the applied voltage waveform used in the activation step, and the maximum voltage value to be applied is usually selected as appropriate within a range of 10 to 20V. In FIG. 4A, T1 is a positive and negative pulse width of the voltage waveform, T2 is a pulse interval, and the positive and negative absolute values of the voltage value are set equal. In FIG. 4B, T1 and T1 ′ are the positive and negative pulse widths of the voltage waveform, T2 is the pulse interval, and T1> T1 ′, and the voltage values have the same positive and negative absolute values. Is set.

  The activation process is performed while measuring the device current or emission current (current emitted as electrons from the electron emission portion 5), and can be terminated when the device current or emission current reaches a desired value. Note that the pulse width, pulse interval, pulse peak value, and the like of the applied pulse voltage are also appropriately set according to the type of carbon compound, its gas pressure, and the like.

  As shown in FIG. 2, the coating 6 provided in the adjacent region of the electron emission portion 5 is usually provided after the activation step, and the coating 6 in this example is provided on the face plate 11. Further, it is made of the same material as the metal back 13 (see FIG. 1) exposed on the surface of the phosphor 12. That is, the metal back 13 is a conductive film composed of a metal or a metal compound material, and the film 6 in this example is composed of the same metal or metal compound material as the metal or metal compound material constituting the metal back 13. It is what has been. Therefore, even if the metal or metal compound material constituting the metal back 13 drops and adheres to the region adjacent to the electron emission portion 5 of the electron emission element 8 due to long-term image display, it is emitted in advance by the same metal or metal compound material coating 6. The electron-emitting device 8 in which the initial efficiency is improved while increasing the current can greatly suppress the change in characteristics as compared with the case where the coating 6 is not provided in advance.

  The film 6 in this example is the same metal or metal compound material as the constituent material of the metal back 13 as described above, but the surface of the metal back 13 is a film of a getter material made of a metal or metal compound material ( (Not shown) and the getter material is exposed, the same metal or metal compound material as the metal or metal compound material constituting the getter material film is used as the film 6. .

  As a constituent material of the metal back 13, aluminum generally used in CRT is used, and as a getter material, barium, titanium or the like is used. Accordingly, when the metal back 13 is exposed on the surface of the phosphor 12 of the face plate 11, the same aluminum as the constituent material of the metal back 13 is used as the coating 6, and a getter material coating is further formed on the surface of the phosphor 12. In the case of being exposed, barium, titanium, or the like, which is the same as the getter material, is used as the coating 6.

  In the case of the electron-emitting device 8 formed through the activation process, the film 6 is formed after the activation process. When the constituent material is the same as the constituent material of the metal back 13, the coating 6 can be formed by the same technique as the formation of the metal back 13, for example, a vacuum film forming technique such as sputtering or vacuum deposition. In addition, when the constituent material is the same as the constituent material of the getter material, the same method as the getter material attaching method, that is, when it is a non-evaporating type, for example, it can be attached by a sputtering method, etc. For example, it can be performed by energization heating and flashing. In addition to the aluminum, barium, and titanium, materials applicable to the coating 6 include metals such as chromium, zinc, and molybdenum and compounds thereof, alkali metals such as cesium, potassium, and lithium, and compounds thereof. The vacuum film forming technique can be applied as a method of forming the film 6, but since it is a very thin film having high reactivity, a consistent vacuum process that does not expose to the atmosphere after the film 6 is formed is desirable.

  The film 6 has a thickness of 0.2 nm to 0.2 nm in order not to cause a harmful effect that the function of the electron-emitting device is lost or the reactive current that does not contribute to the electron emission increases and the performance of the electron-emitting device is significantly deteriorated. It is necessary to set it to 4.5 nm. If the thickness is less than 0.2 nm, it is difficult to obtain the effect of forming the film 6, and if it exceeds 4.5 nm, the function as an electron-emitting device is lost, or the increase in reactive current causes performance deterioration. Make it easier. A preferable thickness of the film 6 is 0.3 nm to 4 nm. If the thickness of the coating 6 is within this range, it can be provided on the entire surface of the electron-emitting device or the entire rear plate of the image display device.

The image display device shown in FIG. 1 is manufactured by forming the film 6 and then facing the rear plate 7 and the face plate 11 in a vacuum chamber and sealing the two through a support frame 14. be able to. This sealing is performed by appropriately evacuating the inside of the vacuum chamber with an exhaust device that does not use oil, such as an ion pump or a sorption pump, and performing a getter treatment as necessary, with 1.3 × 10 ⁻³ to It is preferable to carry out after making the atmosphere of an organic substance having a pressure of about 1.3 × 10 ⁻⁵ Pa sufficiently small.

  The image display device of the present invention can be used as an image display device as an optical printer configured using a photosensitive drum or the like in addition to a display device for a television broadcast, a video conference system, a computer, or the like. it can.

  Hereinafter, the present invention will be described in detail by way of specific examples. However, the present invention is not limited to these examples, and the replacement and design of each element within a range in which the object of the present invention is achieved. This includes changes made.

[Example 1]
First, a Pt paste is printed by an offset printing method on a glass substrate 1 (size 350 × 300 mm, thickness 5 mm) on which a SiO ₂ layer is formed, and then heated and fired to form device electrodes 2 and 3 having a thickness of 50 nm. did. Also, by printing Ag paste by screen printing and heating and baking, Y direction wiring 9 (240 lines) and X direction wiring 10 (720 lines) are formed, and the Y direction wiring 9 and the X direction wiring 10 are formed. At the intersection, an insulating paste was printed by screen printing and heated and fired to form an insulating layer.

  Next, using a bubble jet (registered trademark) type spraying device between the device electrodes 2 and 3, a palladium complex solution is dropped and heated at 350 ° C. for 30 minutes to form a conductive film 4 made of fine particles of palladium oxide. Formed. The film thickness of the conductive film 4 was 20 nm.

  As described above, the element structure before formation of the electron emission portion 5 including the pair of element electrodes 2 and 3 and the conductive film 4 straddling the element electrodes 2 and 3, the Y-direction wiring 9 and the X-direction wiring 10. An electron source substrate 1 on which a matrix wiring comprising:

Around the electron source substrate 1, with the ends of the Y-direction wiring 8 and the X-direction wiring 10 exposed as extraction electrodes, a hood-like lid is covered so as to cover the entire substrate 1, and a vacuum pump (here, In order to remove moisture considered to be attached to the piping of the exhaust device and the electron source substrate 1 after exhausting to about 1.33 × 10 ⁻¹ Pa with a scroll pump), a heater for the piping and the electron source substrate Using the heater for 1, the temperature was raised to 120 ° C., held for 2 hours, and then gradually cooled to room temperature.

After the temperature of the electron source substrate 1 returned to room temperature, it was evacuated with a vacuum pump until the pressure in the hood-like lid reached 2 × 10 ⁻³ Pa. Further, nitrogen gas mixed with 2% hydrogen was introduced, a voltage was applied from the external power source to the ends of the Y-direction wiring 9 and the X-direction wiring 10 which were taken out from the hood-like lid and exposed as electrodes, and the device electrode 2 , 3, the electron emission portion 5, which is a crack in an electrically high resistance state, was formed in the conductive film 4. The forming voltage waveform is the waveform shown in FIG. 3A. In this embodiment, the pulse width T1 is 0.1 msec, the pulse interval T2 is 10 msec, and the peak value is 10V.

Subsequently, an activation treatment was performed using the hood-shaped lid. Similar to the forming described above, a pulse voltage was repeatedly applied from the outside to the device electrodes 2 and 3 through the X direction wiring 10 and the Y direction wiring 8. In this step, tolunitrile was used as a carbon source and introduced into the vacuum space between the hood-like lid and the substrate 1 through a slow leak valve to maintain 1.3 × 10 ⁻⁴ Pa. The voltage is applied as shown in FIG. 4A, the pulse width T1 is 1 msec, the pulse interval T2 is 10 msec, and the peak value is 16V.

  Energization was stopped when the device current reached almost saturation after about 60 minutes, the slow leak valve was closed, and the activation process was completed.

  Next, an image display device was manufactured using the electron source substrate 1 obtained by the above steps.

  First, the rear plate 7 on which the electron source substrate 1 and the support frame 14 were fixed, and the face plate 11 on which the phosphor 12 and the metal back 13 were formed were introduced into the integrated vacuum processing apparatus. Indium for joining the face plate 11 and the rear plate 7 is previously disposed on the support frame 14. The integrated vacuum processing apparatus includes a mechanism capable of independently heating both the rear plate 7 and the face plate 11, and further, the distance between the two can be arbitrarily changed by a vertical drive mechanism. did.

  After the face plate 11 and the rear plate 7 set in the integrated vacuum processing apparatus are baked at 350 ° C. in a state where the distance between both is sufficiently opened, degassing from the face plate 11 and the rear plate 7 is performed. The temperature of the face plate 11 and the rear plate 7 was cooled to 180 ° C., and the ribbon-like barium getter material was energized and flashed toward the face plate 11 for vapor deposition. The deposited film thickness of barium was about 30 nm. The barium film on the metal back 13 is intended to keep the pressure in the panel low by adsorbing and exhausting residual gas in the panel after the sealing process is completed.

  After that, the ribbon-like barium getter material was energized and flashed in the same manner as described above to form barium on the rear plate 7. In order to reduce the vapor deposition speed at this time, the amount of energization at the time of flashing was reduced and the vapor deposition time was shortened, so that the vapor was deposited on the entire surface of the rear plate 7 with a film thickness of approximately 2 nm.

  After depositing barium on the face plate 11 and the rear plate 7 as described above, the distance between the two is gradually reduced until the distance defined by the height of the spacer (not shown) is reached. The face plate 11 and the rear plate 7 were joined by an indium portion previously arranged on the support frame 14. After completion of the bonding, the image display device was cooled to room temperature to complete a vacuum sealed image display device.

  A driver was connected to the image display device thus obtained, and the characteristics of the electron-emitting devices 8 were evaluated and the test pattern was displayed. As a result, the initial electron emission efficiency per one electron-emitting device 8 was 1.3%. The emission current was 15 microamperes. Further, the electron emission efficiency was kept constant even after driving for 5000 hours, and the absolute value of the emission current did not change. Further, in this panel, the emission current did not increase and the electron emission efficiency did not increase regardless of the display pattern, so that the initial uniformity was maintained.

[Comparative Example 1]
In order to confirm the effect of Example 1, an image display device using a rear plate 7 on which barium was not deposited was produced.

  The initial electron emission efficiency of the obtained image display device is 0.8%, which is approximately ½ of that of the first embodiment, and the initial emission current is approximately ５, which is approximately one fifth of that of the first embodiment. It was microampere. Further, the emission current of the white display portion after driving for 5000 hours increased to about three times the initial value, and the electron emission efficiency increased to about 1.2 times. On the other hand, since the characteristics of the black display portion did not change from the initial state even after 5000 hours, a large luminance distribution was created in the display area of one image forming apparatus.

[Example 2]
After vapor deposition of barium on the face plate 11 in Example 1, a titanium getter material was attached on the barium film to a thickness of 50 nm by RF sputtering. The rear plate 7 was provided with only titanium with a thickness of 3 nm without forming a barium film. In order to control the thickness of titanium, the RF power was reduced and the sputtering pressure was increased to reduce the deposition rate to about 0.1 nm / second. An image display device was manufactured in the same manner as Example 1 except for these.

  As a result, the initial emission current was twice that of the conventional configuration, the efficiency was almost twice, and the characteristics were maintained after 5000 hours.

Example 3
Embodiments except that the face plate 11 was not exposed to vapor deposition of barium and the aluminum metal back 13 was exposed, and the rear plate 7 was formed by depositing aluminum with a thickness of 2 nm on the entire surface. In the same manner as in Example 1, an image display device was produced. Here, vapor deposition of 2 nm of aluminum on the entire surface of the rear plate 7 was performed by electron beam vapor deposition in a vacuum apparatus just before the face plate 11 and the rear plate 7 were bonded together.

  As a result, the initial electron emission efficiency was 1.1%, the initial emission current was 5.0 microamperes, and there was almost no change even after 5000 hours.

Example 4
Using the same method as in Examples 1, 2, and 3, an image display device was produced in which a film of barium, titanium, and aluminum was attached to the entire surface of the rear plate 7 with a film thickness of 0.2 nm.

  As a result, in the image display device provided with 0.2 nm barium, the initial electron emission efficiency is 1.2%, the initial emission current is 6.0 microampere, and 0.2 nm titanium is used. In the attached image display device, the initial electron emission efficiency is 1.0%, the initial emission current is 4.5 microamperes, and in the image display device attached with 0.2 nm aluminum, The initial electron emission efficiency was 1.0%, and the initial emission current was 4.5 microamperes. In any of the above image display devices, the electron emission efficiency and the emission current after 5000 hours hardly changed. .

Example 5
Using the same method as in Example 4, an image display device was produced in which a coating of barium, titanium, and aluminum was applied to the entire surface of the rear plate 7 to a thickness of 4.5 nm.

  As a result, in the image display device provided with 4.5 nm barium, the initial electron emission efficiency was 1.0%, the initial emission current was 13 microamperes, and 4.5 nm titanium was attached. In the image display device, the initial electron emission efficiency is 1.0%, the initial emission current is 4.0 microamperes, and in the image display device provided with 4.5 nm aluminum, The electron emission efficiency was 1.0%, and the initial emission current was 4.5 microamperes. In any of the above image display devices, the electron emission efficiency and the emission current hardly changed after 5000 hours.

[Comparative Example 2]
Using the same method as in Example 4, an image display device was produced in which a film of barium, titanium, and aluminum was provided on the entire rear plate 7 to a thickness of about 5.0 nm. When the drive circuit was connected to this image display device and the characteristics of the electron-emitting device 8 were evaluated and the test pattern was displayed, the short-circuiting of the device portion occurred in any material, resulting in an extremely low efficiency and an electron emission function. The desired properties could not be obtained due to extinction.

  Table 1 shows a comparison of the characteristics of the rear plate 7 depending on the vapor deposition material.

It is a partially cutaway perspective view showing an example of an image display device according to the present invention. FIGS. 2A and 2B are schematic views illustrating a basic configuration example of an electron-emitting device used in the image display apparatus of FIG. 1, in which FIG. It is a figure which shows the example of the applied voltage waveform used for forming. It is a figure which shows the example of the applied voltage waveform used for activation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electron source substrate 2, 3 Element electrode 4 Conductive film 5 Electron emission part 6 Metal or metal compound coating 7 Rear plate 8 Electron emission element 9 Y direction wiring (lower wiring)
10 X direction wiring (upper wiring)
11 Face plate 12 Phosphor 13 Metal back 14 Support frame 15 High voltage terminal

Claims (6)

A rear plate including a plurality of electron-emitting devices each including a pair of electrodes and a conductive film having an electron-emitting portion disposed between the electrodes, and fluorescence for displaying an image by irradiation of electrons from the electron-emitting devices In an image display device in which a body and a face plate provided with a coating of a metal or a metal compound material exposed on the surface of the phosphor are arranged opposite to each other,
On the conductive films of the plurality of electron-emitting devices, a film of the same metal or metal compound material as the metal or metal compound material that forms the film exposed on the surface of the phosphor has a thickness of 0.2 nm to 4.5 nm. An image display device characterized by being provided.   The image display device according to claim 1, wherein the metal or metal compound material film exposed on the surface of the phosphor is a metal back provided on the surface of the phosphor.   The image display device according to claim 2, wherein the constituent material of the metal back is aluminum or a metal compound containing aluminum as a main component.   2. The metal or metal compound material coating exposed on the surface of the phosphor is a getter material coating provided on the surface of a metal back provided on the phosphor surface. The image display device described.   The image display device according to claim 4, wherein the getter material is barium, a metal compound containing barium as a main component, titanium, or a metal compound containing titanium as a main component. In the manufacturing method of the image display apparatus in any one of Claims 1-5,
A method of manufacturing an image display device, comprising: sealing a rear plate and a face plate after forming a coating on the conductive film.

Images