JP2000251782A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent separation of a metal back and static discharge during image display, by providing a transparent electrode in the same range as that of at least the metal back on the opposite side of the surface of a face plate which faces an electron source, and impressing a voltage satisfying a specific relation. SOLUTION: A second substrate 1017 has a fluorescent film 1018 on the surface on the first substrate 1015 side, a metal back 1019 is provided on the fluorescent film 1018, a transparent electrode 1022 in a range same as that of the metal back 1019 on the opposite side surface to the first substrate 1015 side surface, and a voltage satisfying an equation I, an equation II, and an equation III is impressed on them. V1 is a voltage applied between the first substrate 1015 side surface of the second substrate 1017 and an opposite surface of this surface, V2 is a voltage applied between the first substrate 1015 side surface and the second substrate 1017 side surface of the fluorescent film 1018, and Va is a voltage applied to the metal back 1019. d1, d2 and ρ1, ρ2 respectively represent thicknesses and volume resistances of the second substrate 1017 and the fluorescent film 1018.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electron beam emitting device and an image forming method for a display device or the like as an application thereof.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a hot cathode device and a cold cathode device, are known.

[0003] Among them, a cold cathode device is, for example, a surface conduction type emission device or a field emission type device (hereinafter referred to as FE type).
And a metal / insulating layer / metal type emission element (hereinafter referred to as MIM type).

As a surface conduction type emission element, for example,
M. I. Elinson, Radio Eng. Ele
ctron Phys. , 10, 1290, (196
5) and other examples described later are known.

[0005] The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. As this surface conduction type emission element, Sn described by Elinson et al.
In addition to those using an O2 thin film, those using an Au thin film [G. Dittmer: "Thin Solid Fi
lms ", 9,317 (1972)] and In2O3 / S
nO2 thin film [M. Hartwell and
C. G. FIG. Fonstad: "IEEE Trans.
ED Conf. , 519 (1975)] and those using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1,
No. 22, 22 (1983)].

[0006] Among the image forming apparatuses using the above-mentioned electron-emitting devices, a flat display device having a small depth has attracted attention as a replacement for a cathode ray tube display device because of its space saving and light weight. .

FIG. 1 is a perspective view showing an example of a display panel portion forming a flat-panel image display device, in which a part of the panel is cut away to show the internal structure. In the figure, 311
5 is a rear plate, 3116 is a side wall, 3117 is a face plate, and a rear plate 3115, a side wall 311
The 6 and f face plate 3117 form an envelope (airtight container) for maintaining the inside of the display panel at a vacuum. The rear plate 3115 has a substrate 3111
Are fixed, but NXM cold cathode elements 3112 are formed on the substrate 3111. (N and M are 2
The above positive integer is set as appropriate according to the target number of display pixels. ) Also, the NXM cold cathode devices 3
Reference numeral 112 denotes M row-direction wirings 311 as shown in FIG.
Three and N column-directional wirings 3114 are provided.
The part constituted by the substrate 3111, the cold cathode element 3112, the row direction wiring 3113 and the column direction wiring 3114 is called a multi electron beam source. In addition, the row direction wiring 3
An insulating layer (not shown) is formed between at least the portion where the column 113 and the column direction wiring 3114 intersect, so that electrical insulation is maintained.

On the lower surface of the face plate 3117, a phosphor film 3118 made of a phosphor is formed, and phosphors (not shown) of three primary colors of red (R), green (G), and growth (B) are applied. Divided. A black body (not shown) is provided between the phosphors of the respective colors constituting the fluorescent film 3118, and a metal back 3119 made of Al or the like is formed on the surface of the fluorescent film 3118 on the rear plate 3115 side. ing. The function of the metal back is as follows: (1) The specific resistance is generally 10E10 (E is a power) to 10E12 ohm-c.
prevention of potential drop due to accumulation of electric charge in a phosphor having a high m and (2) functioning as an electron beam accelerating electrode,
(3) Improvement of brightness by specular reflection of light emitted from the phosphor toward the inner surface of the device, function of preventing the phosphor from being damaged by collision of negative ions, and the like.

Materials suitable for this purpose are usually Al
Is used. The metal back is formed by performing a process called filming (a process of applying an organic film on the black stripe and the phosphor) after forming a pattern of the black stripe and the phosphor, which is a black body, and then forming Al using a vacuum apparatus. This is performed by firing and removing the organic film. Dx1-D
xm and Dy1 to Dyn and Hv are electric connection terminals having an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown). Dx1 to Dxm are the row direction wiring 3113 of the multi-electron beam source and Dy1 to Dy1.
Dyn is a column-directional wiring 3114 of the multi-electron beam source,
Hv is electrically connected to the metal back 3119, respectively.

The inside of the hermetic container is maintained at a vacuum of about 10 −6 Torr, and as the display area of the image display device increases, the rear plate 3115 due to a pressure difference between the inside of the hermetic container and the outside. Further, means for preventing deformation or destruction of the face plate 3117 is required. The method of increasing the thickness of the rear plate 3115 and the face plate 3116 not only increases the weight of the image display device, but also causes image distortion and parallax when viewed from an oblique direction. On the other hand, in FIG. 1, a structural support (called a spacer or a rib) 3120 made of a relatively thin glass plate and supporting the atmospheric pressure is provided. Thus, the substrate 3111 on which the multi-beam electron source is formed and the fluorescent film 31
The space between the face plates 3116 where the 18 is formed is usually maintained at a sub-millimeter to several millimeters, and the inside of the airtight container is maintained at a high vacuum as described above.

In the image display apparatus using the display panel described above, when a voltage is applied to each cold cathode element 3112 through the external terminals Dx1 to Dxm and Dy1 to Dyn, electrons are emitted from each cold cathode element 3112. At the same time, a high voltage of several hundreds [V] to several [kV] is applied to the metal back 3119 through the external terminal Hv to accelerate the emitted electrons and cause them to collide with the inner surface of the face plate 3117. As a result, the phosphors of each color forming the fluorescent film 3118 are excited and emit light, and an image is displayed.

[0012]

In the display panel of the image display device described above, we have studied to display an image with higher luminance, and have found the following problems.

That is, a multi-beam electron source and a face plate 3 are used to accelerate electrons emitted from the cold cathode device 22.
A high voltage of several kV or more, and preferably close to 10 kV, between the metal back 3119 and the metal back 3119 (interval of about 1 to 5 mm)
Since a high electric field of 2 kV / mm or more is applied, the Coulomb force in the direction of the multi-beam electron source largely acts on the metal back. As a result, the face plate and the phosphor
If the adhesion between the metal backs is insufficient, the metal back may come off, collide with the rear plate having the multi-beam electron source, and a phenomenon causing discharge may be observed.

[0014]

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned problems when a member such as a conventional metal back is provided, and prevents an electric discharge at the time of displaying an image and obtains an image for obtaining a good display image. A display device is provided.

The present invention is achieved by an image forming apparatus having the following configuration. That is, in an image forming apparatus including a first substrate having an electron-emitting device and a second substrate having a fluorescent film and a metal back, the second substrate has a surface on the first substrate side. The phosphor film is disposed on the phosphor film, the metal back is disposed on the phosphor film, and a transparent electrode at least in the same region as the metal back is disposed on a surface opposite to the surface on the first substrate side. The thickness of the second substrate is d ₁ , the volume resistivity is ρ ₁ , the thickness of the phosphor film is d ₂ , the volume resistivity is ρ ₂ , and the second substrate is The voltage applied between the first substrate side surface and the surface opposite to the first substrate side is V ₁ , the fluorescent film, the first substrate side surface and the second The voltage applied to the substrate side surface is V ₂ , the voltage applied to the metal back is Va, and the distance between the first substrate and the second substrate is d. When you do

[0016]

[Outside 2] Is established.

The present invention is further characterized in that a spacer is provided between the first substrate and the second substrate.

As described above, by grounding the surface of the face plate opposite to the phosphor, it is possible to prevent the metal back from peeling off, prevent discharge during image display, and obtain an image for obtaining a good display image. A display device is provided.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the configuration and manufacturing method of a display panel of an image forming apparatus to which the present invention is applied will be described with reference to specific examples.

FIG. 2 is a perspective view of an example of a display panel to which the present invention is applied, and a part of the panel is cut away to show the internal structure.

In the figure, 1015 is a rear plate, 1016
Is a side wall, 1017 is a face plate, and 1015 is a side plate.
An airtight container for maintaining the inside of the display panel at a vacuum is formed by 1017 to 1017. When assembling an airtight container, it is necessary to seal the joints of each member to maintain sufficient strength and airtightness.For example, apply frit glass to the joints, and in air or nitrogen atmosphere, Sealing was achieved by baking at 400 to 500 degrees for 10 minutes or more. The inside of the airtight container is 10
Is maintained at a vacuum of about -6th power [Torr], so that the spacer 102 is used as an anti-atmospheric structure in order to prevent breakage of the airtight container due to atmospheric pressure or unexpected impact.
0 is provided.

On the lower surface of the face plate 1017, a fluorescent film 1018 is formed. Since this embodiment is a color display device, phosphors of three primary colors of red, green, and blue used in the field of CRT are separately applied to a portion of the fluorescent film 1018. The phosphor of each color is, for example, as shown in FIG.
As shown in FIG. 2, black members 1010 are provided between stripes of the phosphor. The purpose of providing the black member 1010 is to prevent the display color from being shifted even if there is a slight shift in the irradiation position of the electron beam, and to prevent the reflection of external light to prevent the display contrast from being lowered. Things.

The method of applying the phosphors of the three primary colors is not limited to the stripe arrangement shown in FIG. 3A, but may be, for example, a delta arrangement as shown in FIG. Other arrangements may be used.

When a monochrome display panel is manufactured, a monochromatic phosphor material may be used for the phosphor film 1018, and a black member is not necessarily used.

A metal back 1019 known in the field of CRTs is provided on the rear plate side surface of the fluorescent film 1018.
Is provided. The metal back 1019 has a fluorescent film 10
A part of the light emitted from the mirror 18 is specularly reflected to improve the light utilization factor, protect the fluorescent film 1018 from collision of negative ions, and act as an electrode for applying an electron beam acceleration voltage. In addition, there is a function as a conductive path for electrons that have excited the fluorescent film 1018. The metal back 1019 is formed by forming a fluorescent film 1018 on a faceplate substrate 1017, smoothing the surface of the fluorescent film, and forming an A
1 was formed by a vacuum deposition method. Note that any material other than Al may be used as long as it has the above function.

As shown in FIG. 4, a transparent electrode 1022 made of ITO is provided on at least the region where the metal back exists on the upper surface (atmospheric side surface) of the face plate.
Grounded. Accordingly, even if a high voltage of several kV or more (that is, a high electric field of 2 kV / mm or more) is applied between the multi-beam electron source and the metal back 1019 on the face plate 1017, the face plate is applied to the metal back. Coulomb force from the transparent electrode 1022 on the upper surface acts, so that it does not peel off. This will be described quantitatively. The thickness and volume resistivity of the face plate are d ₁ and ρ ₁ , respectively,
The thickness and volume resistivity of the phosphor film are d ₂ and ρ ₂ respectively,
In addition, the voltage applied between the front and back
V ₁ , the voltage applied between the metal back side surface of the phosphor film and the face plate side surface is V ₂ , the voltage applied to the metal back is Va, and the distance between the face plate and the rear plate is d.
Then, since the face plate and the phosphor can be regarded as a series resistor,

[0027]

[Outside 3] Holds. Here, from the experiment

[0028]

[Outside 4] And found that the metal back could not be peeled off. Therefore, a face plate that satisfies the above equations (1) to (3) at the same time is manufactured. Alternatively, when the image forming apparatus is driven to display an image, a driving method that simultaneously satisfies Expressions (1) to (3) is employed, so that a discharge at the time of image display due to peeling of the metal back is prevented. Suppressed and a good display image can be obtained.

In the case where a monochromatic phosphor is used as the phosphor film, ρ1 of the phosphor film means the specific resistance of the phosphor itself, and three primary color phosphors of red, blue and green are used. In this case, it means the average value of the specific resistance of each color phosphor itself.

Further, as described above, when the black member is provided on the fluorescent film, the black member may come into contact with the metal back. In such a case, an insulator is mainly used as the black member, and the volume resistivity ρ1 of the phosphor film is a value obtained by taking the average of the volume resistivity of the phosphor and the volume resistivity of the black member. Becomes

When the conductive black member does not contact the metal back, or when the conductive black member contacts the metal back, the resistance of the contact portion is high.
Or, when the specific resistance of the black member itself is high and the potential of the fluorescent film on the metal plate side of the fluorescent film substantially differs from the potential of the fluorescent film on the face plate (glass substrate) side of the fluorescent film. Is the average value of the volume resistivity of the phosphor constituting the phosphor film and the volume resistivity of the black member is defined as the volume resistivity ρ1 described above.

Next, an electron-emitting device substrate that can be used in the image forming apparatus of the present invention will be described.

The electron source substrate used in the image forming apparatus of the present invention is formed by arranging a plurality of cold cathode devices on the substrate.

As a method of arranging the cold cathode elements, a ladder type arrangement in which the cold cathode elements are arranged in parallel and both ends of each element are connected by wiring (hereinafter, referred to as a ladder type arrangement electron source substrate).
Alternatively, a simple matrix arrangement in which the X-direction wiring and the Y-direction wiring of a pair of device electrodes of the cold cathode device are connected (hereinafter, referred to as a simple matrix arrangement)
Matrix-type electron source substrate).
Note that an image forming apparatus having a ladder-type arranged electron source substrate requires a control electrode (grid electrode) which is an electrode for controlling the flight of electrons from the electron-emitting devices.

The rear plate 1015 has a substrate 1011
Is fixed, but the cold cathode element 1012 is provided on the substrate.
N × M are formed. (N and M are positive integers of 2 or more and are appropriately set according to the target number of display pixels. For example, in a display device for displaying high-definition television, N = 3000, M It is desirable to set the number to be equal to or greater than 1000.) The N × M cold cathode elements are arranged in a simple matrix by M row-directional wirings 1013 and N column-directional wirings 1014. The part constituted by 1011 to 1014 is called a multi-electron beam source.

The multi-electron beam source used in the image display device of the present invention is not limited in the material, shape or manufacturing method of the cold cathode device as long as the cold cathode device is a simple matrix wiring or a ladder-shaped electron source. Absent. Therefore, the multi-electron beam source includes, for example, a surface conduction electron-emitting device and an F
E-type or MIM-type cold cathode devices can be used.

Next, the structure of a multi-electron beam source in which surface conduction emission devices are arranged as cold cathode devices on a substrate and arranged in a simple matrix will be described.

FIG. 5 is a plan view of the multi-electron beam source used for the display panel of FIG. On the substrate 1011, surface conduction electron-emitting devices are arranged, and these devices are wired in a simple matrix by row-direction wiring electrodes 1013 and column-direction wiring electrodes 1014. An insulating layer (not shown) is formed between the row-directional wiring electrodes 1013 and the column-directional wiring electrodes 1014 at the intersections of the electrodes to maintain electrical insulation.

The multi-electron beam source having such a structure includes a row-direction wiring electrode 1013, a column-direction wiring electrode 1014, an inter-electrode insulating layer (not shown), and a surface conduction type emission element. After the device electrode 1040 and the conductive thin film were formed, power was supplied to each device via the row-direction wiring electrode 1013 and the column-direction wiring electrode 1014 to perform a current forming process and a current activation process.

In this embodiment, the substrate 1011 of the multi-electron beam source is fixed to the rear plate 1015 of the airtight container.
When 11 has a sufficient strength, the substrate 10 of the multi-electron beam source is used as a rear plate of the hermetic container.
11 itself may be used.

Dx1 to Dxm, Dy1 to Dyn, and Hv are electric connection terminals having an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown). Dx1 to Dxm are the row wirings 10 of the multi-electron beam source.
13, Dy1 to Dyn are column-directional wirings 1014 of a multi-electron beam source, and Hv is a metal back 1 of a face plate.
019 electrically.

Next, the spacer will be described.

FIG. 6 is a schematic sectional view taken along the line AA 'of FIG. 2, and the numbers of the respective parts correspond to those of FIG. A high resistance film 1020c is formed on the surface of the spacer itself to prevent electrification, and is provided with conductivity. The spacers 1020 are arranged in a necessary number and at a necessary interval to achieve the above-mentioned object, and are provided inside the face plate and the substrate 10.
11 is fixed to the surface of the substrate 11 by a bonding material 1041. In the embodiment described here, the shape of the spacer 1020 is a thin plate, is arranged in parallel with the row wiring 1013, and is electrically connected to the row wiring 1013.

As the spacer 1020, the substrate 1011
Has insulating properties enough to withstand high voltage applied between the upper row direction wiring 1013 and column direction wiring 1014 and the metal back 1019 on the inner surface of the face plate 1017;
In addition, it is necessary to have conductivity enough to prevent the surface of the spacer 1020 from being charged. This is as described above.

The insulating member 1020a of the spacer 1020
Examples thereof include quartz glass, glass having a reduced content of impurities such as Na, soda lime glass, and ceramic members such as alumina. The insulating member 102
It is preferable that Oa has a coefficient of thermal expansion close to that of the member forming the airtight container and the substrate 1011.

The bonding material 1041 needs to have conductivity so that the spacer 1020 is electrically connected to the row wiring 1013 and the metal back 1019. That is, frit glass to which a conductive adhesive, metal particles, or a conductive filler is added is preferable.

In order to evacuate the inside of the airtight container, after the airtight container is assembled, an exhaust pipe (not shown) and a vacuum pump are connected, and the inside of the airtight container is raised to the power of 10 −7 [Torr].
Evacuate to a degree of vacuum. Thereafter, the exhaust pipe is sealed, but a getter film (not shown) is formed at a predetermined position in the airtight container immediately before or after the sealing in order to maintain the degree of vacuum in the airtight container. The getter film is, for example, Ba
Is a film formed by heating and vapor-depositing a getter material mainly composed of a heater or high-frequency heating, and the inside of the airtight container is 1 × 10−5 due to the adsorbing action of the getter film.
The pressure is maintained at a vacuum of 1 × 10 −7 [Torr].

In the image display apparatus using the display panel described above, when a voltage is applied to each cold cathode element 1012 through the external terminals Dx1 to Dxm and Dy1 to Dyn, electrons are emitted from each cold cathode element 1012. At the same time, a high voltage of several hundred [V] to several [kV] is applied to the metal back 1019 through the external terminal Hv to accelerate the emitted electrons and collide with the inner surface of the face plate 1017. As a result, the phosphor of each color forming the fluorescent film 1018 is excited and emits light, and an image is displayed.

Normally, the voltage applied to 1012 to the surface conduction electron-emitting device of the present invention, which is a cold cathode device, is 12 to 16
[V] degree, metal back 1019 and cold cathode element 101
The distance d between the metal back 1019 and the cold cathode element 1012 is 5 [k].
V] to about 10 [kV].

The basic structure and manufacturing method of the display panel according to the embodiment of the present invention and the outline of the image display device have been described above.

[0051]

In the embodiment described below, as the multi-electron beam source, NxM (N = 307) surface conduction electron-emitting devices having an electron-emitting portion in the conductive film between the electrodes described above are used.
2, M = 1024), and a multi-electron beam source using matrix wiring (see FIG. 2) with M row-directional wirings and N column-directional wirings was used.

The fluorescent film, which is the image forming member, is shown in FIG.
As shown in (c), each color phosphor R, G, B adopts a stripe shape extending in the Y direction, and the black conductive material separates not only between the color phosphors but also between the pixels in the Y direction and a spacer. A shape including a portion for installing 1020 was used. The thickness of the phosphor film is 0.02 mm. First black member 1
No. 010 was formed, and phosphors of each color were applied to the gaps to form phosphor films. A slurry method was used as a method of applying a phosphor on a glass substrate. In addition, the metal back provided on the inner surface side of the fluorescent film performs a smoothing process (usually called filming) on the inner surface of the fluorescent film after forming the fluorescent film,
Thereafter, a transparent electrode of ITO was provided on the upper surface of the face plate, that is, the surface on the atmosphere side, in a range covering the metal back, and this was grounded. The thickness of the face plate is 1 mm.

First, a spacer prepared by forming a silicon nitride film on a glass surface of the same quality as a rear plate having a length of 20 mm, a height of 2 mm and a thickness of 0.2 mm by a 0.5 μm sputtering method as an insulating member 1020 is provided. The antistatic film 10
As 20c, a 50 nm thick chromium oxide film was laminated.
Next, as a low-resistance film 1020b, a 30 μm band parallel to the connection with the face plate and the rear plate is formed at the connection with the face plate and the rear plate.
An Au film having a thickness of 0.1 μm was formed (FIG. 7). Here, the low-resistance film 1020b means that the antistatic film 1020c is a high-potential-side face plate 1017 (eg, a metal back 1019).
And the substrate 1011 (wirings 1013 and 1014) on the low potential side.
Etc.) for electrical connection.

The low-resistance film 1020b is formed of the antistatic film 102
It is sufficient to select a material having a sufficiently low resistance value as compared with 0c, such as a metal such as Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, Pd, or an alloy, and Pd, Ag, Au, Printed conductors composed of glass, such as metals and metal oxides such as RuO2 and Pd-Ag,
Alternatively, it is appropriately selected from a transparent conductor such as In2O3-SnO2 and a semiconductor material such as polysilicon.

The spacer is connected to the metal back on the X-direction wiring and the face plate using conductive frit glass. As the conductive frit glass, a mixture of frit glass and a filler whose surface is coated with gold is used, and is electrically connected to the antistatic film on the spacer surface and the X-direction wiring or face plate.

In this embodiment, a display panel on which the spacer 1020 shown in FIG. Hereinafter, this will be described in detail with reference to FIGS. First, a row direction wiring electrode 1013 and a column direction wiring electrode 101 are previously formed on a substrate.
4. an inter-electrode insulating layer (not shown), a substrate 10 on which a device electrode 1040 of a surface conduction electron-emitting device and a conductive thin film are formed
11 was fixed to the rear plate 1015. Next, the above-mentioned spacers were fixed on the row wirings 1013 of the substrate 1011 at regular intervals in parallel with the row wirings 1013. Thereafter, the fluorescent film 1018 is applied on the inner surface 2 mm above the substrate 1011.
And a face plate 1017 provided with a metal back 1019 via a side wall 1016, and a rear plate 1
015, the face plate 1017, the side wall 1016 and the spacer 1020 were fixed. Substrate 101
1 and rear plate 1015, rear plate 10
Flit glass (not shown) was applied to the joint between the side wall 1016 and the side wall 1016, and the joint between the side wall 1016 and the face plate 1017 was sealed by firing at 400 ° C. to 500 ° C. for 10 minutes or more in the atmosphere.

The spacer 1020 is formed on the substrate 1011.
A conductive frit glass (not shown) in which conductive material such as conductive filler or metal is mixed on the row direction wiring 1013 (line width 300 [μm]) on the side and on the metal back 1019 surface on the face plate 1017 side. Placed through,
400 ° C to 500 ° C in air at the same time as sealing the airtight container
By baking for 10 minutes or more, bonding and electrical connection were also performed.

In this embodiment, the spacer 10
20 is a black conductor (line width) parallel to the row direction (X direction)
300 [μm]) via a metal back 1019. When the above-described sealing is performed, the phosphors of each color must correspond to the elements arranged on the substrate 1011. Therefore, the rear plate 1015, the face plate 1017, and the spacer 1020 are sufficiently aligned. Was done.

The interior of the hermetically sealed container completed as described above is evacuated by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the container is closed through terminals Dx1 to Dxm and Dy1 to Dyn. Direction wiring electrode 1013 and column direction wiring electrode 10
The multi-electron beam source was manufactured by supplying power to each element through the above-mentioned and performing the above-described energization forming process and energization activation process.

Then, the exhaust pipe (not shown) was welded by heating with a gas burner at a degree of vacuum of about 10 −6 [Torr] to seal the envelope (airtight container).

Finally, gettering was performed to maintain the degree of vacuum after sealing.

In the image display apparatus using the display panel as shown in FIGS. 2 and 7 completed as described above, each cold cathode element (surface conduction type emission element) 1012 has external terminals Dx1 to Dx1. Through Dxm and Dy1 to Dyn, a scanning signal and a modulation signal are applied from signal generation means (not shown) to emit electrons, and a metal back 1019 is applied with a high voltage through a high voltage terminal Hv to emit an electron beam. The image was displayed by accelerating and causing electrons to collide with the fluorescent film 1018 to excite and emit phosphors of each color (R, G, B). The applied voltage Vf between the wirings 1013 and 1014 was 14 [V]. The applied voltage Va to the high voltage terminal Hv is 12 [kV]. At this time, when the potential (V1) at the boundary between the phosphor and the face plate was measured,
[V]. this,

[0063]

[Outside 5] Substituting into

[0064]

[Outside 6] It certainly satisfies the formula. As a comparative example, when the surface of the face plate was not grounded before, the distance between the face plate and the rear plate was 2 mm,
The applied voltage Va to the high voltage terminal Hv is 8 [kV] to 10
There was an example of peeling at [kV].

As described above, since the metal back is provided on the back surface of the phosphor, the purpose of the metal back is to prevent a decrease in potential, function as an accelerating electrode, and emit light from the phosphor by specular reflection. And the phosphor can be prevented from being damaged by collision of negative ions. At the same time, since the surface of the face plate was grounded via the transparent electrode, it was possible to prevent the metal back from peeling off from the face plate. As a result, a discharge phenomenon that was considered to be caused by the peeling of the metal back film was not observed, so that a high-luminance image was stably obtained for a long time.

[0066]

As described above, according to the present invention,
A rear plate with an electron source, a phosphor on the surface facing the electron source that emits light by electrons emitted from the electron source, and a metal back on the phosphor that controls the electrons emitted from the electron source. In an image forming apparatus having a face plate, a transparent electrode is provided on a surface opposite to a surface where the face plate faces the electron source, at least in the same range as the metal back, and a voltage closer to the electron source voltage than a high voltage is applied. Accordingly, it has become possible to provide an image display device for preventing a metal back from peeling, preventing discharge during image display, and obtaining a good display image.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional image display device with a display panel partially cut away.

FIG. 2 is a perspective view of an image display device according to an embodiment of the present invention, in which a part of a display panel is cut away.

FIG. 3 is a cross-sectional view illustrating a phosphor array of a face plate of a display panel.

FIG. 4 is a cross-sectional view of a display panel according to an embodiment of the present invention.

FIG. 5 is a plan view of a multi-electron beam source of the image display device according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view of a display panel according to an embodiment of the present invention.

FIG. 7 is a sectional view of a display panel of the image forming apparatus according to the first embodiment.

[Explanation of symbols]

3111, 1011 substrate 3112, 1012 cold cathode element 3113, 1013 row direction wiring 3114, 1014 column direction wiring 3115, 1015 rear plate 3116, 1016 side wall 3117, 1017 face plate 3118, 1018 fluorescent film 3119, 1019 metal back 3120, 1020 structure Support (referred to as spacer or rib) 1022 Transparent electrode 1020a Insulating member of spacer 1020 1020b Low-resistance film of spacer 1020 1020c High-resistance film of spacer 1020 1040 Element electrode of electron-emitting device 1041 Bonding material 1010 Black conductor

Claims (2)

[Claims] 1. An image forming apparatus comprising: a first substrate having an electron-emitting device; and a second substrate having a fluorescent film and a metal back, wherein the second substrate is the first substrate. The fluorescent film is disposed on the side surface, the metal back is disposed on the fluorescent film,
Further, a transparent electrode at least in the same region as the metal back is disposed on a surface opposite to the surface on the first substrate side, wherein the thickness of the second substrate is d ₁ , the volume resistivity is Ρ ₁ , the thickness of the phosphor film is d ₂ , the volume resistivity is ρ ₂ , and the second substrate has a surface on the first substrate side and a surface opposite to the surface on the first substrate side. the voltage applied between the surface V _1, the fluorescent film, V ₂ the voltage applied between the first substrate side surface and the second substrate-side surface, the voltage to be applied to the metal back Is Va and the distance between the first substrate and the second substrate is d. An image forming apparatus characterized in that the following relationship is satisfied. 2. The image forming apparatus according to claim 1, further comprising a spacer between the first substrate and the second substrate.