JP2000133165A - Fluorescent surface member and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the electron emitting characteristic of an electron emitting element while lowering oxygen as the gas for deteriorating the electron emitting element and water by forming a metal back of a metal-backed oxide preventing metal layer formed by laminating on an aluminum layer with Au or Pt or the alloy thereof. SOLUTION: A phosphor 4, an aluminum metal back layer 5 having 100 nm of film thickness, and a platinum layer 6 having 10 nm of film thickness are laminated on a glass substrate 1. This laminated structure is heated at 450 deg.C by an incinerator for 10 minutes in the atmospheric air. A fluorescent surface member is set in a pre-treatment chamber, and baked at 300 deg.C for 10 hours, and thereafter, temperature of the fluorescent surface member is lowered to the room temperature, and carried into a measurement chamber. Accelerating voltage at 10 kV is applied to the fluorescent surface member, and electron is irradiated to the fluorescent surface member by an impregnated type cathode, and emission current is regulated so as to obtain 200 cd of luminance, and electron is irradiated to the fluorescent surface. Film thickness of a layer of Au or Pt or the alloy thereof is regulated at 5-30 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor member used for a display device by electron irradiation and an image forming apparatus using the phosphor member, for example, having an electron-emitting device.

[0002]

2. Description of the Related Art Normally, a phosphor screen member used in this type of display device has a structure as shown in FIG. here,
Reference numeral 1 denotes a substrate glass of the fluorescent screen member, and 2 denotes SiO _2.
Reference numeral 3 denotes a conductive film layer made of ITO or the like, reference numeral 4 denotes a phosphor that emits light by electron irradiation, and reference numeral 5 denotes a metal back layer. As a conventional example, Si
In some cases, the O ₂ layer 2 or the ITO film 3 is not provided.

In a normal fluorescent screen member, electrons collide with a fluorescent screen (phosphor) from the side opposite to the observer. For this reason, a metal thin film having a high light reflectance and a high electron transmittance is attached to the back side of the fluorescent screen, and the light on the back side is reflected to the front side to improve the brightness. Further, the metal thin film eliminates a potential drop phenomenon on the fluorescent screen, and can prevent burning of the fluorescent screen due to ion bombardment.

[0004] In this case, after the electrons pass through the metal film,
To stimulate the phosphor, the film thickness needs to be as small as possible in order to minimize electron energy loss. Aluminum has a low specific gravity (2.68989).
g / cm ³ ), so the rate of absorbing electron energy is small, the reflectivity is high, and it is easy to vapor-deposit in vacuum.
Suitable as metal back (electronic tube for TV P6
2-P64, see Ohmsha Akira Yamashita).

Although the principle of the metal back fluorescent screen is simple, a special technique is required to actually form the screen. This is because, since the particle size of the phosphor particles is larger than the thickness of the aluminum film, if aluminum is directly deposited on the phosphor, a conductive film is not formed. Therefore, usually, a metal back layer is formed after an organic polymer is formed on a phosphor, and then a metal back is formed by firing and decomposing the organic polymer between the aluminum film and the phosphor. are doing.

[0006]

However, when the phosphor screen is irradiated with an electron beam, gas is released from the phosphor screen.
The emitted gas (particularly, water, oxygen, or the like) may deteriorate the electron emission characteristics of the electron source. Therefore, a method of reducing gas generated from the phosphor screen has been considered.
In order to suppress the generation of gas from the phosphor screen, the number of water molecules in the phosphor film is reduced.To this end, in the step of forming the phosphor screen on the inner surface of the face by a precipitation method, the water molecules on the phosphor screen are reduced. A method has been proposed in which high-temperature dry air having a desorption energy or more is blown (see JP-A-6-295667).

Further, a method has been proposed in which unnecessary gas remaining in a vacuum vessel (vacuum envelope) is reduced, and gas emission generated during electron impact is reduced (Japanese Patent Laid-Open No. 6-2037).
No. 55). In this method, in the heat treatment step of the cathode ray tube manufacturing process, the atmosphere in the heating furnace is changed to dry air or an inert gas with low moisture in the frit baking step, and the dry air or dry nitrogen with low moisture in the cooling process after the heating is completed. In addition, the inert gas is supplied and replaced to suppress the adsorption of water molecules in the vacuum vessel.

The deterioration of the electron emission characteristics of the electron source due to the emitted gas is particularly caused by the FED (Japanese Patent Laid-Open No. 6-260) which is a display using a field emission type electron emission element.
No. 116, etc.) are widely known. In these displays, it is difficult to arrange as many getters as necessary and sufficient in the hermetic container because there is a limitation in arranging getters that adsorb and exhaust the released gas. Furthermore, since the panel is thin, the conductance in the panel is small and the effective pumping speed is small. Therefore, since the released gas is released beyond the exhaust capability of the getter, the amount of the deteriorating gas of the electron source in the hermetic container increases, so that the electron emission characteristics of the electron source are likely to deteriorate.

The gas emitted by irradiating the phosphor screen with electrons degrades the electron emission characteristics of the electron source. Water, oxygen, sulfur oxide, and the like are considered as such gases. However, in order to operate a field emission type or surface conduction type cold cathode electron source stably for a long time, it is necessary to further reduce the deteriorated gas. However, since the adsorption energy of the chemical adsorption is larger than that of the physical adsorption, the method using the above-mentioned heat treatment step has a limit in the reduction of the released gas particularly caused by the chemical adsorption.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide an electron-emitting device which emits electrons when a fluorescent screen is irradiated with electrons generated by the electron-emitting devices in a vacuum vessel. It is an object of the present invention to provide a phosphor screen member in which the emission characteristics of an electron-emitting device are stably operated for a long time by reducing oxygen and water as deteriorating gases.

Another object of the present invention is to provide an image display device in which the luminance does not change with time by using such a phosphor screen member.

[0012]

In order to achieve the above object, according to the present invention, in a phosphor screen member having at least a phosphor and a metal back covering the phosphor, the metal back has an aluminum layer on the phosphor side. And a metal back oxidation preventing metal layer made of Au, Pt, or an alloy thereof on the aluminum layer.

Here, the thickness of the metal back oxidation preventing metal layer is formed in the range of 5 nm to 30 nm, or the thickness of the aluminum layer is set to 20 nm to 200 nm.
It may be formed in the following range.

According to the present invention, in the image display apparatus using the phosphor screen member having the metal back oxidation preventing layer, the phosphor is excited by using electrons generated from the electron-emitting device.

In this case, the electron-emitting device may be a surface conduction electron-emitting device or a field emission electron-emitting device.

That is, generally, the degassing process in an airtight container (vacuum envelope) is performed at 200 ° C. to 35 ° C.
A 0 ° C. high temperature baking process is performed. Even after performing this high-temperature baking treatment, a large amount of gas is adsorbed in the panel. Therefore, when the face plate is irradiated with accelerated high-energy electrons on the panel after baking, gas is generated. That is, gas is generated from the face plate fluorescent surface. This gas is chemically adsorbed on the face plate, and usually, the adsorbed gas that cannot be removed in the baking step is desorbed for the first time by irradiation of high-energy electrons. The deterioration gas, H ₂ O, O ₂ and the like.

Therefore, in order to operate the electron-emitting device stably, it is necessary to remove gas (-OH, -O) chemically adsorbed on the face plate as much as possible or to reduce the gas from the initial state. If the initial adsorption amount is small, the emission of H ₂ O and O ₂ can be suppressed when electrons are irradiated.

The vacuum surface of the current face plate is made of aluminum metal back. Aluminum easily oxidizes (also forms hydroxides) in the atmosphere, which is considered to be a major factor in the emission of the deteriorating gas from the electron-emitting device. In general, an image forming apparatus having an electron-emitting device has an airtight structure. A high temperature sealing step is performed when forming the container. The sealing process is usually a high temperature process at 400 ° C. or higher.

Therefore, as described above, in the present invention, the vacuum surface is chemically stable even through a sealing process.
It is made of a metal such as t or Au. This makes it possible to suppress the gas released from the metal back when the high-energy electrons are irradiated on the face plate. As a result, the emission gas of water and oxygen when the electron-emitting device is driven can be reduced, and the electron-emitting device can be operated more stably for a long time.

Further, since the metal back needs to have an optimum film thickness in order to transmit electrons or to sufficiently increase the reflectance, the above-described range is set as an embodiment of the present invention in the present invention. desirable. That is, it is desirable that the metal back antioxidant layer has a sufficient film thickness to cover the aluminum, but the metal used for the metal back antioxidant layer, gold or platinum, has a mean free path of electrons. Is about one order of magnitude smaller than aluminum. Therefore, when the film thickness of gold or platinum is large, electrons cannot collide with the phosphor, and sufficient luminance cannot be obtained. Therefore, in the present invention, it is necessary to reduce the thickness of gold and platinum. As a result, the thickness of the aluminum oxidation preventing layer needs to be the above-mentioned optimum thickness. The aluminum layer needs to have a thickness greater than or equal to a thickness required to sufficiently reflect light from the phosphor. Further, the thickness of the aluminum layer is determined so that the thickness must be equal to or less than the thickness that does not suppress the electron transmission performance of the metal back.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below. In FIG.
A phosphor screen member according to this embodiment is schematically illustrated. Here, reference numeral 1 denotes a glass substrate 1 which is a substrate of a phosphor screen member, on which a phosphor 4, an aluminum metal back layer 5, and platinum 6 are laminated as an aluminum oxidation preventing layer. In this embodiment, the thickness of the aluminum metal back layer 5 is 100 nm, and the thickness of the platinum layer 6 is 10 nm.

First, this phosphor screen member was subjected to a high-temperature treatment in air at 450 ° C. for 10 minutes in a firing furnace. This temperature is the working temperature of the frit sealing step in forming a normal panel. Next, the emitted gas at the time of electron irradiation was measured for the phosphor screen member by an electron impact desorption measuring device. FIG. 2 schematically shows the electron impact desorption measuring apparatus.

Here, reference numeral 11 denotes a pre-processing chamber for performing vacuum baking of the fluorescent screen, 12 denotes a heater for heating the fluorescent screen member 18, and 13 denotes a vacuum between the pre-processing chamber 11 and the electron impact desorption measuring chamber 14. An airtight gate valve 15 is an impregnated cathode for causing electrons to collide with a fluorescent screen member 18 as a measurement sample. Reference numeral 16 denotes a quadrupole mass spectrometer (Q-ma) for measuring the released gas in the measurement chamber 14.
ss), and 17 is a luminance meter for measuring the luminance of the phosphor screen of the phosphor screen member.

First, the fluorescent screen member 18 was set in the pre-processing chamber 11, where baking was performed at 300 ° C. for 10 hours. Next, after the temperature of the phosphor screen member was lowered to room temperature, it was carried into the measurement chamber 14 by a transport system (not shown), and the phosphor screen member 18 was irradiated with electrons by the impregnated cathode 15. At this time, the electron acceleration voltage was set to 10 kV. At this time, the emission current was regulated by the luminance meter 17 so that the luminance became 200 cd. When the phosphor screen was irradiated with electrons, the quadrupole mass spectrometer 16 measured the amount of gas released from the phosphor screen member by the electron irradiation.

Quadrupole mass spectrometer 1 hour after electron irradiation
Table 1 shows the ionic current of the H ₂ O and O ₂ gases of No. 6. At this time, H ₂ O is m / e = 18, O ₂ is m /
Monitored at e = 32. The ionic current amount in Table 1 indicates a value obtained by subtracting a background current when the fluorescent screen is not irradiated with electrons. That is, the values in Table 1 show the ion current values of the gas desorbed by irradiating the phosphor screen with electrons.

Similarly, in the film configuration of the phosphor screen shown in FIG. 1, when the thickness of the aluminum film 5 is set to 50 nm and the gold as the aluminum oxidation preventing layer 6 is set to 15 nm, the same process is performed as described above. A measurement was made. Further, when the film thickness of the aluminum layer 5 is 80 nm, and the film made of an alloy of platinum (80 wt%) and gold (20 wt%) as the aluminum oxidation preventing layer is 12 nm, the same process is performed as described above. Was measured.

As a comparative example, the same measurement was performed on the phosphor screen member having the configuration shown in FIG. 9 through the same process as in the above-described embodiment. However, the thickness of the aluminum metal back layer 5 was 200 nm.

[0028]

[Table 1] As described above, in the embodiment of the present invention, by using platinum, gold and their alloys as the aluminum oxidation preventing layer, high-energy electrons of several kV or more are emitted when the phosphor screen is irradiated. It was confirmed that the amount of H ₂ O and O ₂ gas could be reduced.

(Second Embodiment) A second embodiment of the present invention will be described below. Here, for the phosphor screen member shown in FIG. 1, when platinum is adopted as the aluminum oxidation preventing layer 6 when the thickness of the aluminum layer 5 is fixed at 50 nm, high energy electrons are applied to the phosphor screen due to the platinum film thickness. The emission gas upon irradiation was measured. The measuring method and process are the same as those in the first embodiment, and the measuring device shown in FIG. 2 is used. The acceleration energy of the electrons at the time of this measurement was 10 kV, the emission current amount was 200 c, and the luminance was 200 c.
d.

FIG. 3 shows the results. The horizontal axis shows the platinum film thickness, and the left vertical axis shows the amount of H ₂ O gas released by electron irradiation. This is a normalized value of the amount of released gas when the thickness of the aluminum layer is 200 nm in the phosphor screen member having the configuration shown in FIG. 9 as a comparative example. The right vertical axis represents the emission current amount when the luminance becomes 200 cd, and the luminance on the phosphor screen of the phosphor screen member of the comparative example is 2.
This is a standardization of the emission current amount at the time of 00 cd.

In FIG. 3, when the thickness of the antioxidant layer increases, the transmittance of electrons to the phosphor decreases, so that it is necessary to increase the irradiation amount of electrons in order to keep the luminance constant. I understand. In particular, when the film thickness of platinum exceeds 30 nm, it is necessary to rapidly increase the irradiation amount of electrons in order to keep the luminance constant. Increasing the electron irradiation amount also increases the amount of H ₂ O released gas. In addition, when the amount of emitted electrons is increased, the load on the electron emission source that emits electrons is increased, so that the life is expected to be shortened. Therefore, in order to extend the life of the electron emission source, at least the amount of emitted electrons must be reduced to a normal value of 1.2.
It is desirable to keep it below about twice.

If the thickness of the aluminum oxidation preventing layer 6 is small, the aluminum film 5 cannot be uniformly covered. When the thickness of the antioxidant layer is less than 5 nm, the effect of the antioxidant layer is insufficient. Therefore, it is desirable that the thickness of the antioxidant layer be set to an appropriate thickness or more. That is,
It was experimentally confirmed that the effect was enhanced by setting the thickness of the antioxidant layer to 5 nm or more and 30 nm or less.

In the second embodiment of the present invention, platinum is used as the material of the aluminum antioxidant film 6. However, the same applies when gold or an alloy of platinum and gold is used instead of platinum. I can say that.

(Third Embodiment) Next, a third embodiment of the present invention will be described. Here, for the phosphor screen member shown in FIG.
When the thickness was fixed at 0 nm, the emission gas when the phosphor screen was irradiated with high-energy electrons was measured for the value when the thickness of the aluminum layer 5 was changed. The measuring method and process are the same as those of the above-described embodiment, and the measuring apparatus shown in FIG. 2 is used. The acceleration energy of the electrons during this measurement was set to 10 kV, and the emission current amount was defined so that the luminance became 200 cd.

FIG. 4 shows the result. The horizontal axis represents the aluminum film thickness, and the left vertical axis represents H emitted by electron irradiation.
_The amount of ₂ O gas is a value obtained by standardizing the amount of released gas when the thickness of the aluminum layer is 200 nm for the phosphor screen member having the configuration of FIG. 9 as a comparative example. The right vertical axis indicates the emission current amount when the luminance becomes 200 cd, and the luminance on the phosphor screen of the phosphor screen member of the comparative example is 200 c.
This is standardized by the amount of emission current at d.

As can be seen from FIG. 4, the aluminum film is
If the film thickness is too thick, the transmission of irradiated electrons through the metal back
Since the rate decreases, in order to obtain the required brightness,
It is necessary to increase the dose. Reduces the amount of emission current
In order to achieve this, the thickness of aluminum should be 200 nm or less.
Aluminum must be generated from the phosphor.
The film thickness is sufficient to reflect the fluorescent light
It is necessary and must be more than a certain film thickness. Immediately
In order to efficiently reflect the light generated from the phosphor,
Requires that the aluminum film thickness be 20 nm or more.
You. That is, the film thickness of aluminum is not less than 20 nm and not more than 200 nm.
nm or less, H _TwoO release
It was experimentally confirmed that the gas was efficiently suppressed.

In this embodiment, platinum is used as the material of the aluminum oxidation preventing film 6. However, substantially the same can be said when gold or an alloy of platinum and gold is used instead of platinum. .

(Fourth Embodiment) In a fourth embodiment of the present invention, the impregnated cathode is an electron-emitting device generally used in a CRT. A measurement was made. In the apparatus shown in FIG. 2, after the impregnated cathode was activated in vacuum and sufficiently aged, the change in emission current with time when the heater current of the cathode was kept constant and the acceleration voltage was 15 kV Was tested with the fluorescent screen member 18.

Here, the thickness of the aluminum film 5 is set to 12
0 nm, 10% platinum as the aluminum oxidation preventing layer 6
nm. Further, FIG. 5 shows a temporal change of the emission current with respect to the operation time of the impregnated cathode when the initial emission current is set to 2 A / cm ² after aging.
The same measurement was performed on the phosphor screen member of FIG. 9 as a comparative example. The film thickness of aluminum is 200 nm.

In this embodiment, it was confirmed that the life of the impregnated cathode was prolonged by using the phosphor screen member having the metal back structure. this is,
This is because generation of deteriorating gases such as water and oxygen, which are deteriorating gases of the electron source, could be suppressed.

(Fifth Embodiment) In this embodiment, a plurality of surface conduction electron-emitting devices, which are cold cathode electron-emitting devices, are formed on a rear plate as electron-emitting devices, and are opposed to the rear plate. In this manner, the fluorescent screen member (face plate) shown in FIG. 1 was installed, and a color image display device having an effective display area of 15 inches diagonally and a length to width ratio of 3: 4 was produced.

First, an image display device of the present invention will be described with reference to FIG. 6, and then a method of manufacturing the image display device will be described. FIG. 6 is a perspective view of the image display device of this embodiment, in which a part of the panel is cut away to show the internal structure. In the figure, reference numeral 25 denotes a rear plate, 26 denotes a support frame, and 27 denotes a face plate. 25 to 27 form an airtight container (vacuum envelope) for maintaining the inside of the display panel at a vacuum. When assembling the airtight container, it is necessary to seal each member to ensure sufficient strength and airtightness.

In the figure, reference numeral 29 denotes an exhaust pipe for connecting to a vacuum device when evacuating the airtight container to a vacuum.
Further, these exhaust pipes are also used as a gas introduction pipe for an activation gas in an activation step generated during a process step. Reference numeral 28 denotes a Ba evaporable getter prepared for maintaining a vacuum in the airtight container after sealing the exhaust pipe 29. The Ba evaporation type getter forms a Ba vapor deposition film by heating to a high temperature.

On the rear plate 25, N × M surface conduction electron-emitting devices 22 are formed (N and M are positive integers of 2 or more, and are appropriately set according to the target number of display pixels. Is set to.) In the N × M surface conduction electron-emitting devices, a simple matrix wiring is formed by M row-directional wirings 23 (also called lower wirings) and N column-directional wirings 24 (also called upper wirings).

Next, this embodiment will be described with reference to FIG. FIGS. 7A and 7B are schematic diagrams showing the configuration of the surface conduction electron-emitting device. FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view. In FIG. 7, reference numeral 31 is a substrate, 32 and 33 are device electrodes, 34 is a conductive thin film, and 35 is an electron-emitting portion.

While the airtight container is evacuated to a vacuum through an exhaust pipe 29, the conductive thin film 3 is passed through the device electrodes 32 and 33.
By subjecting the conductive thin film to a forming treatment, the conductive thin film is locally destroyed, deformed or altered to form an electron emitting portion 35 in an electrically high-resistance state. When the pressure becomes 10 ⁻³ Pa or less, acetone is introduced as an activating gas into the airtight container through the exhaust pipe 29 at about 1 Pa, and as an activation step for remarkably improving the emission current, the above-described device electrodes 32 and 33 are used. The above-described electron emission section 35 is activated by applying a voltage to the element and causing a current to flow through the element.
235255).

Further, a fluorescent screen member (face plate) 2
7 is a 10 mm P, as described in the first embodiment.
It has the configuration shown in FIG. 1 where t is formed. In this embodiment, since the color display device is used, phosphors of three primary colors of red, green, and blue used in the field of CRT are separately applied to the portion of the phosphor 4. In addition, Dx1 to Dxm and Dy1 to Dyn and Hv
Is an electric connection terminal of an airtight container provided for electrically connecting the display panel to an electric circuit (not shown). The terminals Dx1 to Dxm are the row wiring 23 of the multi-electron beam source, the terminals Dy1 to Dyn are the column wiring 24 of the multi-electron beam source, and the terminal Hv is the metal back 5 and the aluminum oxidation preventing layer 6 of the phosphor screen. , Respectively, are electrically connected.

Next, a method for manufacturing the image display device of the present invention will be described with reference to FIG. (Preparation of Rear Plate) (R-1) Device electrodes 32 and 33 connected to the lower wiring 23 and the upper wiring 24 are formed on the rear plate where the blue glass is washed and a silicon oxide film is formed by a sputtering method. I do.
Subsequently, the lower wiring 23 is formed by screen printing.
An interlayer insulating film is formed between the lower wiring 23 and the upper wiring 24. Further, the upper wiring 24 was formed. (R-2) Next, a conductive thin film 34 made of PdO was formed by an inkjet method. (R-3) frit glass for fixing the support frame,
Formed at desired locations. By the above process, the surface conduction type emission element before forming with simple matrix wiring,
A rear plate on which an adhesive for a support frame and the like were formed was prepared.

(Formation of Face Plate) (F-1) A phosphor and a black conductor were formed on a blue plate glass substrate. A smoothing treatment was performed on the inner surface of the fluorescent film, and thereafter, an Al and Pt layer were deposited using a vacuum evaporation method to form a metal back. (F-2) frit glass for fixing the support frame,
It was formed at a desired position by a printing method. Through the above steps, the phosphor in which the phosphors of the three primary colors are arranged in a stripe shape, the adhesive for the support frame, and the like were formed on the face plate.

(Preparation of Airtight Container by Sealing Rear Plate and Face Plate) (FR-1) The rear plate is held on a hot plate on an X, Y, and θ adjustment stage, and the position of the face plate is adjusted. Then, the rear plate and the face plate are heated to the sealing temperature. The sealing temperature is determined by the type of the frit glass. In this embodiment, the sealing temperature is 410 ° C. Then, at the stage when the temperature is raised to the sealing temperature, the adjustment stages of X, Y, and θ
While performing alignment of the rear plate and the face plate, the support frame was brought into contact with the support frame, and after holding for 10 minutes while applying pressure, the temperature was lowered at 3 ° C. per minute, and the temperature was lowered by 100 ° C. from the sealing temperature. The alignment was stopped, the stage was freed and allowed to cool to room temperature.

(Preparation of Electron Emitting Element by Vacuum Process) (S-1) The exhaust pipe 29 on the face plate of the airtight container prepared as described above is connected to a vacuum exhaust device, and the inside of the airtight container is evacuated. Exhaust. (S-2) When the pressure in the airtight container becomes 0.1 Pa or less, the terminals Dox1 to Doxm and Doy1 to Do outside the container.
A voltage was applied to the electron-emitting device through yn, and a forming process was performed on the conductive thin film 34. (S-3) Subsequently, the pressure in the airtight container is 1 × 10 ⁻³ Pa
When it becomes the following, acetone as an activating gas is introduced into the airtight container through the exhaust pipe 29 at 1 Pa, and a voltage is applied to the electron-emitting device through the terminals Dox1 to Doxm and Doy1 to Doyn outside the container to perform the activation process. went.

(Degassing Step in Hermetic Container) (D-1) After activating gas is sufficiently exhausted, baking degassing of the hermetic container is performed. The baking temperature was 300 ° C., and the rate of temperature rise was 2 ° C. per minute. (D-2) After maintaining the temperature of the hermetic container at 300 ° C. for 10 hours, the temperature is lowered to room temperature, and the Ba evaporation type getter 28 is flashed by high-frequency heating from outside the hermetic container,
A Ba deposited film was formed. (D-3) Thereafter, a part of the exhaust pipe 29 was melted and heated and sealed.

The change over time in the electron emission characteristics in the image display device prepared as described above was measured, and the results are shown in FIG. Note that a pulse waveform of a voltage of 15 V was applied between the electron-emitting devices, and a high voltage of Va = 5 kV was applied to the face plate. At this time, the current flowing through the face plate is defined as Ie. However, values normalized by current values immediately after voltage application are plotted.

As a comparative example, an image display device was formed by the same process as that of the phosphor screen member (face plate) 27 of this embodiment shown in FIG. 9 having a conventional structure. Further, the change over time of the same electron-emitting device as in this embodiment was measured, and the result is shown in FIG. As is apparent from FIG. 8, it was confirmed that the life of the surface conduction electron-emitting device source was prolonged by using the phosphor screen member having the metal back structure of this embodiment. This is because generation of deteriorating gases such as water and oxygen, which are deteriorating gases of the electron source, could be suppressed. In addition,
In this embodiment, a surface conduction electron-emitting device source was employed as the electron-emitting device, but the same effect was experimentally confirmed for a field-emission electron-emitting device.

[0055]

The present invention has been described in detail above. By using platinum or gold, which is a metal that is stable even in a high-temperature process, on the outermost surface of the metal back of the phosphor screen member, or an alloy thereof. It is possible to reduce the amount of chemisorbed gas (mainly O group or OH group) which cannot be degassed even by vacuum high-temperature baking, and the gas generated when accelerated high-energy electrons are irradiated on the surface of the phosphor screen member (face plate) Can be reduced from the initial state.

The O or OH group is a gas which deteriorates the electron emission characteristics of many electron-emitting devices.
It is a source of ₂ O and O ₂ . Therefore, in the embodiment of the present invention, the surface of the phosphor screen member is configured as described above, so that the initial adsorption amount of the O group or the OH group is reduced, and H ₂ is reduced.
O, O ₂ release gas can be suppressed.
As described above, according to the present invention, the phosphor screen enables the electron emission characteristics to be stably operated for a long time, so that an image display device having a long life can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a fluorescent screen member (face plate) showing an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of an electron impact desorption measuring apparatus according to each embodiment.

FIG. 3 is a graph showing the dependence of the relative values of the H ₂ O release gas and the emission current upon the impact of electrons on the phosphor screen with the platinum film thickness.

FIG. 4 is a graph showing the dependence of the relative values of H ₂ O release gas and emission current on the aluminum film thickness during electron impact on the phosphor screen in the third embodiment.

FIG. 5 is a diagram showing a change over time of an emission current of an impregnated cathode according to the fourth embodiment.

FIG. 6 is a schematic diagram of an image forming apparatus using a surface conduction electron-emitting device according to a fifth embodiment.

FIG. 7 is a view showing the configuration of a surface conduction electron-emitting device.

FIG. 8 is a diagram showing a change with time of the electron emission characteristics of the surface conduction electron-emitting device.

FIG. 9 is a schematic cross-sectional view showing a conventional phosphor screen member.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 phosphor screen glass substrate 2 SiO ₂ layer 3 ITO film 4 phosphor 5 aluminum metal back layer 6 aluminum oxidation prevention layer 11 baking pretreatment chamber 14 electron impact desorption measurement chamber 15 impregnated cathode 16 quadrupole mass spectrometer (Q 17 luminance meter 18, 27 phosphor screen (face plate) 22 surface conduction electron-emitting device 28 evaporative getter 29 exhaust pipe 32, 33 device electrode 34 conductive thin film 35 electron-emitting portion

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toru Ariga 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 5C036 BB04 EE01 EE02 EE17 EF01 EF06 EG36 EH08 EH11 EH23

Claims (6)

[Claims] 1. A phosphor screen member having at least a phosphor and a conductive member layer covering the phosphor surface of the phosphor, wherein the conductive member layer has an aluminum layer on the phosphor side, and has an Au layer on the aluminum layer. Alternatively, a phosphor screen member comprising a layer made of Pt or an alloy thereof. 2. The phosphor screen member according to claim 1, wherein
The phosphor screen member, wherein the thickness of the Au, Pt, or alloy thereof is 5 nm or more and 30 nm or less. 3. The phosphor screen member according to claim 1, wherein
A phosphor screen member, wherein the thickness of the aluminum layer is not less than 20 nm and not more than 200 nm. 4. An image forming apparatus having the phosphor screen member according to claim 1, wherein the phosphor excitation uses electrons generated from an electron-emitting device. 5. An image forming apparatus according to claim 4, wherein said electron-emitting device is a surface conduction electron-emitting device. 6. The image forming apparatus according to claim 4, wherein said electron-emitting device is a field emission type electron-emitting device.