JP3305169B2 - Electron beam generator and image forming apparatus using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam generator and an image forming apparatus such as an image display using the same, and more particularly to an electron beam generator and an image forming apparatus having a large number of surface conduction electron-emitting devices. About.

[0002]

2. Description of the Related Art Conventionally, two types of electron-emitting devices, a thermionic electron source and a cold-cathode electron source, are known, and an image forming apparatus using these electron sources is also known.

FIG. 11 shows a known planar image forming apparatus using a thermionic electron source. FIG.
FIG. 2 is a schematic configuration diagram of a conventional image forming apparatus using a thermoelectron source. The image forming apparatus includes a plurality of anodes 1502 disposed in parallel on an insulating support 1501 and having a surface coated with a member (phosphor) that emits light by electron beam impact;
A plurality of filaments 1503 arranged in parallel and opposite to each other, an anode 1502 and a filament 1503
And a plurality of grids 1504 arranged orthogonal to the anode 1502 and the filament 1503,
The anode 1502, the filament 1503, and the grid 1504 are held in a transparent container 1505. The container 1505 is hermetically bonded (hereinafter, referred to as “sealing”) to the insulating support 1501 so that a vacuum inside the container 1505 can be maintained, and the inside of the envelope formed by the container 1505 and the insulating support 1501 The vacuum is maintained at about ^-6 Torr.

The filament 1503 emits electrons by being heated in a vacuum, and by applying an appropriate voltage to the grid 1504 and the anode 1502, the electrons emitted from the filament 1503 collide with the anode 1502, and The phosphor applied on 1502 emits light. A row of anodes 1502 (X direction) and a row of grids 1504 (Y
By performing matrix addressing of (direction), the position of light emission can be controlled, and an image can be displayed through the container 1505.

However, an image forming apparatus using a thermionic electron source has the following disadvantages. (2) Since the modulation speed is slow, it is difficult to display a large capacity. (3) Variations between elements are likely to occur, and the structure is complicated, so that it is difficult to enlarge the screen. There is a problem.

Therefore, an image forming apparatus using a cold cathode electron source instead of a thermionic electron source has been considered.

A field emission type (hereinafter referred to as FE) is used as a cold cathode electron source.
Type), metal / insulating layer / metal type (hereinafter referred to as MIM type), surface conduction electron-emitting devices, and the like.

As an example of the FE type, WPDyke & WWDol
an, "Field emission", Advance inElectron Physics,
8, 89 (1956), or CASPindt, "PHYSICAL Propert
iesof thin-filmfield emission cathodes with moybde
nium coces ", J. Appl. Phys., 47, 5248 (1976).

An example of an image forming apparatus using this FE type electron source will be described with reference to FIG. FIG.
FIG. 2 is a schematic configuration diagram showing a partially enlarged conventional image forming apparatus using a type electron source.

[0010] As shown in FIG.
An electron source 2001 on which a number of electron-emitting devices are formed, and a face plate 200 opposed to the electron source 2001
And 3. The electron source 2001 is provided on the insulating substrate 201.
1 has a number of micropoints 2013 formed electrically connected to each other via a conductor 2012, and an opening corresponding to the micropoints 2013. The micropoints and the 2013 are insulated by an insulating layer 2014 to form an insulating substrate. And a grid 2015 supported by 2011. The diameter and height of the bottom of the micropoint 2013 is about 2 μm, and the opening diameter of the grid 2015 is also about 2 μm.
m. The face plate 2003 is a glass plate 20
A phosphor 2032 coated on the inner surface of the phosphor 31;
32, and a conductive film 2033 acting as an acceleration electrode to which a voltage for accelerating the electrons emitted from the micropoint 2013 is applied.

In the above structure, the micropoint 20
13 is very small (1 μm or less), and since the tip of the micropoint 2013 is protruding, the distance between the micropoint 20 and the grid 2015 is small.
Strong electric field capable of emitting field electrons even at a potential difference of 100 V or less between 13 and grid 2015 (10 ⁷ V / cm or more)
Can be formed. An electron emission amount from one micropoint 2013 can be obtained in the order of several μA. However, since it is possible to form about tens of thousands of micropoints 2013 per square mm, in an image forming apparatus, usually, several thousands are obtained. An electron emission element corresponding to one pixel is constituted by a set of about tens of thousands of micropoints 2013. Therefore,
An electron emission amount of several mA or more can be obtained per electron emission element corresponding to one pixel.

As the potential applied to the grid 2015 and the micropoint 2013, for example, the grid 201
5 to the ground potential (0V),
Electrons can be emitted by applying a negative potential (about -100 V) to the conductor 13 through the conductor 2012. further,
When a potential equal to or higher than that of the grid 2015 is applied to the face plate 2003 through the conductive film 2033, electrons emitted from the electron source 2001 collide with the phosphor 2032 to excite and emit the phosphor.

In order to control the light emitting point, a plurality of micropoints 2013 are electrically connected to a conductor 20.
A plurality of row wirings 2041 formed by arranging strips 12 in a band in the X direction and column wirings 2042 to which grids 2015 are electrically connected in the Y direction are provided at intersections of the matrix wiring pattern. Electron emitting element regions 2 to be formed
010, external power supplies 2043, 204
4, matrix addressing is performed so that a voltage equal to or higher than a desired electron emission start voltage is applied, and a position where electrons are irradiated to the phosphor 2032 to which the voltage is applied from the acceleration voltage applying power supply 2045 through the conductive film 2033 is selected. Thus, an image can be displayed.

On the other hand, CAMead,
"Operation of Tunnel-emission Devices", J.Appl.Ph
ys., 32, 646 (1961) and the like.

As an example of the surface conduction electron-emitting device, M.
I. Elinson, Radio Eng. Electron Phys., 10, (1965). The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using an SnO ₂ thin film by Elinson et al., A device using an Au thin film [G. Dittmer: “Thin Solid Films”, 9, 317 (1972)],
n ₂ O ₃ / SnO ₂ thin film [M. Hartwell and C.G.
Fonstad: "IEEE Trans. ED Conf.", 519 (1975)], and a method using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, p. 22 (1983)] and the like have been reported.

As a typical example of the device configuration of these surface conduction electron-emitting devices, the above-mentioned M.D. FIG. 13 shows a plan view of the device by Hartwell et al. In FIG.
Reference numeral 01 denotes a substrate, and reference numeral 3004 denotes a conductive thin film made of a metal oxide formed by sputtering. The conductive thin film 3004 is formed in an H-shaped planar shape as shown. An electron emission portion 3005 is formed by performing an energization process called energization forming described later on the conductive thin film 3004. The interval L in the figure is 0.5 to 1 mm, and W is 0.1
mm. For convenience of illustration, the electron emitting portion 305 is shown in a rectangular shape at the center of the conductive thin film 3004, but this is a schematic shape, and the position and shape of the actual electron emitting portion are faithfully represented. I am not doing it.

M. In the above-described surface conduction type electron-emitting device including the device by Hartwell et al., The conductive thin film 3004 is subjected to an energization process called energization forming before electron emission, so that the electron emission portion 3 is formed.
005 was commonly formed. That is, the energization forming means that a constant DC current or a DC current which is stepped up at a very slow rate of, for example, about 1 V / min is applied to both ends of the conductive thin film 3004 and energized. Is locally destroyed, deformed, or altered to form an electron-emitting portion 3005 in an electrically high-resistance state. Note that a crack is generated in a part of the conductive thin film 3004 that is locally broken, deformed, or altered. When an appropriate voltage is applied to the conductive thin film 3004 after the energization forming, electron emission is performed in the vicinity of the crack.

Since the above-mentioned cold cathode electron source can be formed by using, for example, a technique such as photolithography and etching, it is possible to arrange a large number of elements at minute intervals. Moreover, as compared with a thermionic source, the cathode and the peripheral portion can be driven at a relatively low temperature, so that a multi-electron beam generating source having a finer arrangement pitch can be easily realized. Among such cold cathode electron sources, particularly, a surface conduction electron-emitting device has an advantage that the device structure is simple and easy to manufacture, and it has an advantage that a large-area one can be easily manufactured. It is suitable as an electron-emitting device used in a large-screen image forming apparatus.

For example, in an image forming apparatus using this type of electron-emitting device, as shown in FIG. 14, an electron source 1001 provided with an electron-emitting device is connected to a rear plate 1002.
Image forming member 100 provided with a fluorescent film 1007 that emits light by collision of electrons on the inner surface of a glass substrate 1006
3 is disposed facing the electron source 1001 via a support frame 1004, and the inside of an envelope 1010 formed by a rear plate 1002, an image forming member 1003, and a support frame 1004 is evacuated. . Further, the image forming member 1
003 includes a conductor 1008 that acts as an acceleration electrode for accelerating the electrons emitted from the electron source 1001 toward the image forming member 1003.
When a high voltage is applied to the image forming member 10
03, and collides with the image forming member 1003. Therefore, the support frame 1004 is made of an insulating material that can withstand high voltage.

[0020]

As described above, the conventional image forming apparatus utilizes a phenomenon in which electrons emitted from an electron source collide with a phosphor of an image forming member to emit light. In addition, ions are generated by a reaction when electrons collide with the image forming member or by ionizing an atmospheric gas inside the apparatus. On the other hand, on the inner surface of the image forming member, a conductor 1008 and a support frame 10 for fixing the glass substrate 1006 and the support frame 1004 as shown in FIG.
A gap A is required between the insulating glass substrate and the insulating glass substrate 1006. Therefore, these ions may be charged in the gap A.

For example, when positive ions are charged, the electron source 10
The electrons emitted from 01 deviate from the normal orbit (the orbit indicated by a) and fly outward by the positive ions (the orbit indicated by a ′). Conversely, when the negative ions are charged, the electrons emitted from the electron source 1001 fly inward (orbit indicated by a ″). In any case, the potential of the charged portion becomes unstable, and the orbit of the electrons shifts. In addition, there arises a problem such as a shift of a light emitting position, etc. In addition, a probability that a discharge or the like is caused by a charged charge is increased, and the reliability and life of the device are impaired.

The present applicant has proposed a method of realizing an image forming apparatus using a surface conduction type electron-emitting device with a simpler configuration by using a plurality of row direction wirings and a plurality of column direction wirings. By connecting a pair of device electrodes facing each other of the electron-emitting device, a simple matrix type electron source in which a large number of surface conduction electron-emitting devices are arranged in a matrix is formed. A system capable of selecting a large number of surface conduction electron-emitting devices and controlling the amount of electron emission by giving an appropriate drive signal is being considered. In such a simple matrix type image forming apparatus using the surface conduction electron-emitting device, similarly, the surface of the insulating member may be charged, which may affect the electron trajectory.

The above-mentioned problem that the electron trajectory is displaced also occurs in an electron beam generator in which a phosphor is not used as an electron irradiation member, similarly to the image forming apparatus.

Accordingly, an object of the present invention is to provide an electron beam generator and an image forming apparatus that stabilize the trajectories of emitted electrons by preventing electrification of an electron irradiation member.

[0025]

In order to achieve the above object, an electron beam generator according to the present invention comprises a plurality of row wirings and a plurality of row wirings.
A plurality of electron-emitting devices row is wired by the row direction wirings
An electron source provided in a row, and an electron source arranged to face the electron source in a vacuum atmosphere to irradiate electrons emitted from the electron-emitting device, and to accelerate electrons emitted from the electron-emitting device. in the electron beam generating device having a substrate having an electron irradiated member having an accelerating electrode, said double
When viewed from the electron emitting portion of the electron-emitting device having, when the angle with respect to the direction perpendicular to the surface of the electron source was theta, the group
At least tanθ ≦ 2 on the surface of the plate facing the electron source
It is characterized in that the members within the entire range satisfying the potential are defined with the potential.

[0026] Further, a support frame forming a part of an envelope for maintaining a vacuum atmosphere between the electron source and the electron irradiation member is provided, and an inner surface of the electron irradiation member and the support frame are formed. By forming a conductive film electrically connected to the accelerating electrode on the inner surface, the conductive film forms a member within the above range, and the electron emitting element and the electron-irradiated member When the facing distance is d, the position of the electron irradiation member is at least 2d in any direction on the surface facing the electron source from a position facing the electron emitting portion of the electron emitting element. Since the acceleration electrode is formed, a member in the range defined by the acceleration electrode or an outer periphery of the electron irradiation member is electrically connected to the acceleration electrode, and the electron source Wall-shaped electrode protruding toward By being made, members within said range by said accelerating electrode and the wall-shaped electrode may be one that is configured.

Further, the electron-emitting device may be a cold cathode type electron-emitting device, and in particular, a surface conduction type electron-emitting device may be used.

In this case, a plurality of the surface conduction electron-emitting devices are arranged in a two-dimensional matrix, and each of the surface conduction electron-emitting devices is composed of a plurality of row wirings and a plurality of column wirings. May be connected to each other.

An image forming apparatus according to the present invention uses the electron beam generating apparatus according to the present invention, and is disposed in opposition to the electron source instead of the electron-irradiated member, and electrons emitted from the electron-emitting devices collide. Thus, the image forming member is provided with a phosphor that emits light and an acceleration electrode for accelerating the electrons emitted from the electron-emitting device.

In the electron beam generator of the present invention configured as described above, electrons are emitted from the electron emitting element of the electron source, and when the electrons collide with the electron irradiated member, ions are generated from the electron irradiated member. In addition, in some cases, electrons may collide with a gas present between the electron source and the electron irradiation member to generate ions. On the other hand, assuming that the angle with respect to the direction perpendicular to the surface of the electron source is θ when viewed from the electron-emitting portion of the electron-emitting device, the members within the range satisfying tan θ ≦ 2 are regulated in potential. The entire range in which the electrons emitted from are likely to be irradiated is potential-defined.
As a result, even if the electrons emitted from the electron-emitting device are irradiated, the electron irradiation member is not charged by the ions, and the trajectory of the electrons is stabilized.

Further, a supporting frame is provided between the electron source and the electron irradiation member, and a conductive film electrically connected to the acceleration electrode is formed on the inner surface of the electron irradiation member and the inner surface of the supporting frame. When the potential of the member within the range is reliably defined and the distance between the electron-emitting device and the electron-irradiated member is d, the electron-irradiated member faces the electron-emitting portion of the electron-emitting device. By forming the accelerating electrode within a range of at least 2d in any direction on the surface facing the electron source from the position, the configuration of the member for defining the potential in the range is simplified. Furthermore, by forming a wall-shaped electrode electrically connected to the acceleration electrode on the outer periphery of the electron irradiation member and protruding toward the electron source, a wall-shaped electrode in a range deviating from the acceleration electrode out of the above-described range. Since the potential is defined, the size of the acceleration electrode can be small. As a result, a smaller electron beam generator is configured with the same size of the electron irradiation member.

According to the present invention, a plurality of surface conduction electron-emitting devices are arranged in a matrix by connecting the surface conduction electron-emitting devices with a plurality of row-direction wirings and a plurality of column-direction wirings. It is suitable for an electron beam generator using a simple matrix type electron source. The above-mentioned simple matrix type electron source can select a large number of surface conduction electron-emitting devices and control the amount of electron emission by giving appropriate drive signals in the row direction and the column direction. There is no need to add a control electrode, and it can be easily formed on one substrate.

Of course, the present invention can be applied to a case where some additional structure (for example, a focusing electrode or a deflection electrode) is provided between the electron source and the electron irradiation member. The same effect is provided by applying and determining the configuration of the plurality of electrodes provided on the support member. Furthermore, the present invention can be applied to a case where the additional structure also serves as a part of the plurality of electrodes.

In the image forming apparatus of the present invention, instead of the electron-irradiated member used in the electron beam generating apparatus of the present invention, light is emitted by colliding electrons emitted from the electron-emitting devices, which are arranged opposite to the electron source. Since the image forming member provided with the phosphor and the accelerating electrode for accelerating the electrons emitted from the electron-emitting device is used, the trajectory of the electrons emitted from the electron-emitting device is stabilized as described above. As a result, a good image with no shift in the light emitting position is formed.

[0035]

Next, the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a partially cutaway perspective view of a first embodiment of an image forming apparatus to which an electron beam generator according to the present invention is applied, and FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment.

In FIG. 1, an electron source 1 in which a plurality of surface conduction electron-emitting devices 15 are arranged in a matrix is fixed to a rear plate 2. A face plate 3 as an image forming member having a fluorescent film 7 and a metal back 8 as an accelerating electrode formed on the inner surface of a glass substrate 6 is opposed to the electron source 1 via a support frame 4 made of an insulating material. A high voltage is applied to the metal back 8 by a power supply (not shown). The rear plate 2, the support frame 4, and the face plate 3 are sealed with each other with frit glass or the like, and the rear plate 2, the support frame 4, and the face plate 3 constitute an envelope 10.

As shown in FIG. 2, a conductive film 9 electrically connected to the metal back 8 is formed on the inner surface of the support frame 4 and on the portion of the face plate 3 where the glass substrate 6 is exposed. Have been. The conductive film 9 extends below the electron source 1, and therefore, the junction between the rear plate 2 and the support frame 4 is formed lower than the portion where the electron source 1 is mounted.

The components described above will be described in detail below.

(1) Electron Source 1 FIG. 3 is a plan view of a main part of the electron source of the image forming apparatus shown in FIG. 1, and FIG. 4 is a cross-sectional view of the electron source taken along line AA ′ of FIG. FIG.

As shown in FIGS. 3 and 4, an insulating substrate 11 such as a glass substrate
And n Y-directional wirings 13 are electrically separated by an interlayer insulating layer 14 and wired in a matrix. A surface conduction electron-emitting device 15 is electrically connected between each X-direction wiring 12 and each Y-direction wiring 13.
Each electron-emitting device 15 includes a pair of device electrodes 16 and 17 spaced from each other in the X direction, and
6 and 17, and one of the pair of device electrodes 16 and 17 is connected to X through a contact hole 14a formed in the interlayer insulating layer 14. The other element electrode 17 is electrically connected to the Y-directional wiring 13 while being electrically connected to the directional wiring 12. Each of the element electrodes 16 and 17 is made of a conductive metal or the like, and is formed by a vacuum deposition method, a printing method, a sputtering method, or the like.

The size and thickness of the insulating substrate 11 depend on the number of electron-emitting devices 15 installed on the insulating substrate 11 and the design shape of each device, and a part of the container when the electron source 1 is used. When it is configured, it is appropriately set depending on conditions for maintaining the container in a vacuum.

Each X direction wiring 12 and each Y direction wiring 13
Are made of a conductive metal or the like formed in a desired pattern on the insulating substrate 11 by a vacuum deposition method, a printing method, a sputtering method, or the like, and a voltage as uniform as possible is supplied to a large number of electron-emitting devices 15. Thus, the material, the film thickness, and the wiring width are set. The interlayer insulating layer 14 is made of SiO ₂ or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like, and is formed in a desired shape on the entire surface or a part of the insulating substrate 11 on which the X-directional wiring 12 is formed. In particular, the X-direction wiring 12
To withstand the potential difference at the intersection of the
The thickness, material, and manufacturing method are appropriately set.

The X-direction wiring 12 is electrically connected to a scanning signal generating means (not shown) for applying a scanning signal for arbitrarily scanning a row of the electron-emitting devices 15 arranged in the X-direction. ing. On the other hand, the Y-direction wiring 13 is electrically connected to a modulation signal generating means (not shown) for applying a modulation signal for arbitrarily modulating each column of the electron-emitting devices 15 arranged in the Y direction. . Here, the drive voltage applied to each electron-emitting device 15 is supplied as a difference voltage between the scanning signal and the modulation signal applied to the device.

Here, an example of a method of manufacturing the electron source 1 will be specifically described with reference to FIGS. Note that the following steps a to h correspond to (a) to (h) in FIG.

Step a: A 50 .ANG. Thick Cr film and a 6000 .ANG. Thick Cr film are formed by vacuum deposition on an insulating substrate 11 having a 0.5 .mu.m thick silicon oxide film formed on a cleaned blue plate glass by a sputtering method. After sequentially laminating Au, photoresist (AZ1370 Hoechst) was spin-coated with a spinner and baked.
The photomask image is exposed and developed to form a resist pattern for the X-directional wiring 12, and the Au / Cr deposited film is wet-etched to form the X-directional wiring 12 having a desired shape.

Step b: Next, an interlayer insulating layer 14 of a silicon oxide film having a thickness of 0.1 μm is deposited by RF sputtering.

Step c: A photoresist pattern for forming a contact hole 14a is formed in the silicon oxide film deposited in step b, and the photoresist pattern is used as a mask to form a photoresist pattern.
Is etched to form a contact hole 14a.
Etching is performed by RIE (Rea) using CF ₄ H ₂ and gas.
active ion etching) method.

Step d: Thereafter, a pattern to be a gap between the device electrodes and the device electrode is formed by a photoresist (RD-20).
00N-41 manufactured by Hitachi Chemical Co., Ltd.), and a 50 Å thick Ti and a 1000 Å thick Ni were sequentially deposited by a vacuum evaporation method. The photoresist pattern is dissolved with an organic solvent, the Ni / Ti deposited film is lifted off, and the device electrode 1 having a device electrode interval L1 (see FIG. 3) of 3 μm and a device electrode width W1 (see FIG. 3) of 300 μm.
6 and 17 are formed.

Step e: After forming a photoresist pattern of the Y-directional wiring 13 on the device electrodes 16 and 17,
0 angstrom Ti and 5000 angstrom thick Au are sequentially deposited by vacuum evaporation, unnecessary portions are removed by lift-off, and a Y-directional wiring 1 having a desired shape is formed.
Form 3

Step f: As shown in FIG. 6, a pair of device electrodes 16 and 17 located at an interval L1 between device electrodes.
A Cr film 21 having a thickness of 1000 Å is deposited and patterned by vacuum deposition using a mask 20 having an opening 20a that straddles the organic Pd (ccp).
4230 Okuno Pharmaceutical Co., Ltd.) was spin-coated with a spinner and heated and baked at 300 ° C. for 10 minutes.

The thus formed electron-emitting-portion-forming thin film 18 made of fine particles containing Pd as a main element has a thickness of about 100 Å and a sheet resistance of 5 × 10 ^4.
Ω / □. In addition, the fine particle film described here is a film in which a plurality of fine particles are aggregated.
Not only a state in which the fine particles are individually dispersed and arranged, but also a film in which the fine particles are adjacent to each other or overlapped (including an island shape), and the particle size is a fine particle whose particle shape can be recognized in the above state. About diameter.

Step g: Cr film 21 with acid enchant
Was removed to form an electron-emitting-portion-forming thin film 18 having a desired pattern shape.

Step h: A pattern is formed such that a resist is applied to portions other than the contact hole 14a, and 50 angstrom Ti and 500 thick are formed by vacuum evaporation.
0 Å of Au was sequentially deposited. Unnecessary portions were removed by lift-off to fill the contact holes 14a.

Through the above steps, the X-directional wiring 12, the Y-directional wiring 13, and the electron-emitting devices 15 are formed and arranged two-dimensionally at equal intervals on the insulating substrate 11.

Then, the envelope 10 (see FIG. 1) is evacuated by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the outer terminals Dox1 to Doxm and Dx1
A voltage is applied between the device electrodes 16 and 17 of the electron-emitting device 15 through oy1 to Doyn, and the electron-emitting-portion forming thin film 18 is locally energized by applying current (forming process). The electron emission portions 23 (see FIG. 4) are formed on the thin film 18 for forming electron emission portions by breaking. For example, as forming processing, 10 ^-6 To
Under a vacuum atmosphere of rr, a pulse width T ₁ as shown in FIG.
There one millisecond, a triangular wave wave height (the peak voltage for the forming) is 5V, 10 ms for 60 seconds at a pulse interval T ₂ of the, by energizing between the device electrodes 16 and 17, the thin film for electron-emitting region The electron emission portion 23 is locally destroyed, so that the electron emission portion 23 can be formed in the electron emission portion forming thin film 18.

The electron emitting portion 23 thus formed
Was in a state where fine particles mainly composed of palladium element were dispersed and arranged, and the average particle diameter of the fine particles was 30 angstroms.

(2) Phosphor Film 7 The phosphor film 7 is made of only a phosphor in the case of monochrome, but is called a black stripe or a black matrix depending on the arrangement of the phosphor as shown in FIG. 8 in the case of color. It is composed of a black conductive material 7b and a phosphor 7a. Since the phosphor 7a needs to be arranged corresponding to the electron-emitting device 15, when the envelope 10 is configured, the face plate 3 and the rear plate 2 must be accurately aligned. The purpose of providing the black stripes and the black matrix is to make the mixed colors inconspicuous by making the painted portions between the respective phosphors 7a of the three primary color phosphors necessary for color display less noticeable. The purpose is to suppress a decrease in contrast due to light reflection. As the material of the black conductive material 7b, not only a material mainly containing graphite, which is often used, but also a material having conductivity and low transmission and reflection of light can be applied. The method of applying the phosphor 7a to the glass substrate 6 is not limited to monochrome or color, and a precipitation method or a printing method is used.

(3) Metal Back 8 The purpose of the metal back 8 is to improve the brightness by specularly reflecting the light of the fluorescent light of the phosphor 7a directed toward the inner surface toward the face plate 3 and to reduce the electron beam acceleration voltage. Acting as an accelerating electrode for applying, phosphor 7 from damage caused by collision of negative ions generated in envelope 10
a. The metal back 8 can be manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 7 after manufacturing the fluorescent film 7 and then depositing Al by vacuum evaporation or the like. The face plate 3 may be provided with a transparent electrode (not shown) such as ITO between the fluorescent film 7 and the glass substrate 6 in order to further increase the conductivity of the fluorescent film 7.

(4) Enclosure 10 The envelope 10 is connected to an exhaust pipe (not shown) and is connected to 10 ^-6 Torr.
After a degree of vacuum is applied, it is sealed. Therefore, the rear plate 2, the face plate 3, and the support frame 4 constituting the envelope 10 can withstand the atmospheric pressure applied to the envelope 10, maintain a vacuum atmosphere, and maintain the electron source 1 and the metal back 8.
It is desirable to use a material having an insulating property enough to withstand a high voltage applied therebetween. As the material, for example, quartz glass, glass having a reduced content of impurities such as Na,
Blue sheet glass, ceramic members such as alumina and the like can be mentioned. However, it is necessary to use a face plate 3 having a certain or higher transmittance for visible light. In addition, it is preferable to combine the members whose thermal expansion coefficients are close to each other.

As shown in FIG. 2, a conductive film 9 is formed on the inner surface of the support frame 4 and on the portion of the face plate 3 where the glass substrate 6 is exposed. Is performed as follows.

First, frit glass is applied to the joint between the support frame 4 and the face plate 3 and baked at 400 to 500 ° C. for 10 minutes or more in the air or in a nitrogen atmosphere to separate the support frame 4 and the face plate 3. Seal. Thereafter, the surface of the metal back 8 is masked, and carbon having a thickness of 500 to 1000 angstroms is applied to the inner surfaces of the support frame 4 and the face plate 3 so that the coating range in the Z direction in FIG. Vacuum deposition is performed so as to be larger than the distance d between 1 and the metal back 8. This allows
A conductive film 9 electrically connected to the metal back 8 is formed. In this embodiment, the distance d between the electron source 1 and the metal back 8 is set to 5 mm, and the leading end (the lower end in the figure) of the conductive film 9 is 1 mm from the surface of the electron source 1 (dimension h in FIG. 2). The conductive film 9 was formed so as to be located at. Since the conductive film 9 is electrically connected to the metal back 8,
To prevent electrons emitted from the electron-emitting device 15 from being accelerated toward the support frame 4 by applying a voltage to the metal back 8, the distance from the electron-emitting portion 23 of the electron-emitting device 15 to the conductive film 9 is reduced. Must be large enough. In this embodiment, the distance B from the electron-emitting portion 23 of the electron-emitting device 15 closest to the conductive film 9 to the conductive film 9 was set to 10 mm.

Next, the joining portion of the support frame 3 with the rear plate 2 to which the electron source 1 was fixed was sealed with frit glass to complete the envelope 10.

Since the rear plate 2 is provided mainly for the purpose of reinforcing the strength of the electron source 1, if the electron source 1 itself has a sufficient strength, the rear plate 2 is unnecessary, and is directly connected to the electron source 1. The support frame 4 may be sealed, and the envelope 10 may be configured by the electron source 1, the support frame 4, and the face plate 3.

In some cases, a getter process is performed to maintain the degree of vacuum after sealing the envelope 10. this is,
Immediately before or after sealing of the envelope 10, a getter disposed at a predetermined position (not shown) in the envelope 10 is heated by resistance heating, high-frequency heating, or the like to form a deposition film. Processing. A getter typically contains Ba is a main component, the adsorption effect of the vapor deposition film, for example, 1 × 10 ^-5
It maintains a degree of vacuum of about 1 × 10 ⁻⁷ Torr.

Next, the operation of this embodiment will be described with reference to FIGS.

Each of the electron-emitting devices 15 has a terminal Dox outside the container.
When a voltage is applied through 1 to Doxm and Doy1 to Doyn, electrons are emitted from the electron emission unit 23. At the same by applying a high voltage of several kV or more through a high-voltage terminal H _V to accelerate electrons emitted from the electron emission portion to the metal back 8 (or a transparent electrode (not shown)) at the same time, to impinge on the inner surface of the face plate 3. Thereby, the phosphor 7a (see FIG. 8) of the phosphor film 7 is excited to emit light, and an image is displayed.

The electrons emitted from the electron-emitting device 15 are directed in a direction parallel to the surface of the electron source 1, specifically, on the positive electrode side of each of the device electrodes 16 and 17 (see FIG. 3) of the electron-emitting device 15. Has initial speed in the direction. Therefore, the electrons emitted from the electron-emitting device 15 fly in a parabolic orbit by being accelerated.

Here, the potential difference between the electron-emitting device 15 and the metal back 8 is Va, and the maximum value of the initial initial kinetic energy of the electrons emitted from the electron-emitting device 15 in the horizontal direction is e.
Assuming that Vi (electron volt; e is the amount of charge of electrons), the electrons emitted from the electron-emitting device 15 move in a direction parallel to the surface of the electron source 1 until reaching the metal back 8 separated by the distance d. The distance ΔS is represented by ΔS = 2d × √ (eVi / Va) (1) when the initial velocity of the electrons in the vertical direction is set to 0. In this embodiment, the total thickness of the metal back 8 and the phosphor 7 is about 50 μm or less, and the thickness of the electron-emitting device 15 formed on the insulating substrate 11 (see FIG. 4) is about Since it is 10 μm or less, the distance d between the electron-emitting device 15 and the metal back 8 may be the distance between the insulating substrate 11 and the glass substrate 6 for practical use.

Here, suppose that the electrons emitted from the electron-emitting device 15 receive all of the energy due to the voltage applied to the metal back 8 and fly out in the direction parallel to the surface of the electron source 1. The moving distance ΔS to reach the metal back 8 is calculated by adding Va to Va in the equation (1).
And 2d is obtained. That is, a perpendicular to the surface of the electron source 1 is extended from the electron-emitting portion 23 of the electron-emitting device 15, and a range of a radius 2 d on the inner surface of the face plate 3 around the intersection of the perpendicular with the face plate 3 is as follows: This is a site where electrons emitted from the electron-emitting device 15 may reach. Expressing this as an angle, the range in which electrons may reach is a range satisfying tan θ ≦ 2d / d = 2 (2).

Therefore, if the potential is defined at least in the range that satisfies the expression (2), there is no potential indeterminate surface in the flight direction of the electrons emitted from the electron-emitting device 15, and the electron is not charged. In the present embodiment, as described above,
Since a conductive film is formed on the inner surface of the face plate,
Equation (2) is satisfied. As a result, no charge is generated on the inner surface of the face plate.
The trajectory of the electrons emitted from the semiconductor device was stabilized, and a good image without displacement was obtained. Further, the probability of causing discharge or the like was extremely low, and a highly reliable image forming apparatus was obtained.

Normally, a pair of device electrodes 1 of the electron-emitting device 15
The applied voltage between 6 and 17 is about 12 to 16 V, the distance d between the metal back 8 and the electron source 1 is about 2 mm to 8 mm, and the applied voltage Va of the metal back 8 is about 1 kV to 10 kV. In this embodiment, the applied voltage between the pair of device electrodes 16 and 17 is 14 V, the distance between the metal back 8 and the electron source 1 is 5 mm as described above, and the applied voltage Va of the metal back 8 is 5
kV.

(Second Embodiment) FIG. 9 is a schematic sectional view of a second embodiment of the image forming apparatus of the present invention.

In the present embodiment, a flat plate is used as the rear plate 52, and the size of the metal back 58 is increased instead of forming a conductive film on the inner surfaces of the face plate 53 and the support frame 54. This is different from that of the first embodiment.

The size of the metal back 58 extends from the outermost electron-emitting portion of the electron-emitting device 65 to the surface of the electron source 51 so as to satisfy the above equation (2). To the outside in the X direction and 2d each in the Y direction perpendicular thereto. Here, d is the distance between the metal back 58 and the electron-emitting device 65, and was set to 5 mm in this embodiment as in the first embodiment. Other configurations and driving conditions are the same as those in the first embodiment, and thus description thereof is omitted.

By increasing the size of the metal back 58 in this manner, there is no potential indeterminate surface in the flight direction of the electrons emitted from the electron-emitting device 65, and the inner surfaces of the support frame 54 and the glass substrate 56 are charged. The trajectory of the electrons emitted from the electron-emitting device 65 is stabilized as in the first embodiment, and a good image can be formed. Further, in the present embodiment, since the metal back 58 is merely enlarged, the configuration is very simple.

(Third Embodiment) FIG. 10 is a schematic sectional view of a third embodiment of the image forming apparatus of the present invention.

In this embodiment, a flat plate is used as the rear plate 102. Instead of forming a conductive film on the inner surfaces of the face plate 103 and the support frame 104, the metal back 108 is The difference from the first embodiment is that a wall-shaped electrode 105 electrically connected to the element electrode is provided.

The wall-shaped electrode 105 has at least a tip (not shown) on a straight line extending within a range of tan θ = 2, where θ is the angle between the electron emitting portion of the outermost electron emitting element 115 and a direction perpendicular to the electron emitting portion. (Lower end) is located, and in the above-described equation (2), the potential is defined by the metal back 108 in the range up to the outermost end of the metal back 108, and the potential is defined by the wall-shaped electrode 105 in the range beyond the outermost end. ing. Specifically, at a position where the distance C from the outermost electron-emitting device 115 is 4 mm, the height is 3 mm.
Was provided. The distance between the electron source 101 and the metal back 108 was 5 mm. Wall-shaped electrode 10
The material 5 is not particularly limited as long as it is a conductive material, but here, a 426 alloy having a thickness of 100 μm is used and fixed with frit glass. Other configurations and driving conditions are the same as those in the first embodiment, and thus description thereof is omitted.

By providing the wall-shaped electrode 105 in this manner, there is no potential indeterminate surface in the direction in which the electrons emitted from the electron-emitting device 115 fly, and the inner surfaces of the support frame 104 and the glass substrate 106 are not charged. Therefore, similarly to the first embodiment, the trajectory of the electrons emitted from the electron-emitting device 115 is stabilized, and a good image can be formed. Further, in this embodiment, since the size of the metal back 108 can be reduced, a smaller image forming apparatus can be configured with the same screen size.

In the above embodiment, an example in which the image forming apparatus of the present invention is applied to an image display apparatus has been described. However, the present invention is not limited to this range, and may be applied to an image forming light emitting unit of an optical printer. It can be applied to a recording device, for example, when used. In this case, the image forming units arranged one-dimensionally are often used as a normal mode. However, by appropriately selecting the above-described m row-directional wirings and n column-directional wirings, the line-shaped wirings can be formed. It can be applied not only to a light emitting source but also to a two-dimensional light emitting source.

The electron irradiation object is not specified, and application as an electron beam generator serving as a multi-plane electron source is also possible.

[0083]

Since the present invention is configured as described above, the following effects can be obtained.

In the electron beam generator of the present invention, when the angle with respect to the direction perpendicular to the surface of the electron source is θ when viewed from the electron-emitting portion of the electron-emitting device, members within a range satisfying tan θ ≦ 2 Since the potential is regulated, even if the electrons emitted from the electron-emitting device are irradiated, the electron-irradiated member is not charged by ions generated between the electron source and the electron-irradiated member. Can be stabilized.

Further, by providing a support frame between the electron source and the electron irradiation member, a conductive film electrically connected to the acceleration electrode is formed on the inner surface of the electron irradiation member and the inner surface of the support frame. Thus, the potential of members within the above range can be reliably defined.

Further, when the distance between the electron-emitting device and the electron-irradiated member is d, the position of the electron-irradiated member facing the electron-emitting portion of the electron-emitting device is changed from the position on the surface facing the electron source. By forming the accelerating electrode in at least the range of 2d in any direction, it is possible to simplify the configuration of the member for defining the potential in the range.

Further, by forming a wall-shaped electrode which is electrically connected to the accelerating electrode and protrudes toward the electron source on the outer periphery of the electron-irradiated member, the wall-shaped electrode in the range deviating from the accelerating electrode out of the above-mentioned range. The potential can be defined by the electrode, and a smaller electron beam generator can be configured with the same size of the electron irradiation member.

By using a cold-cathode type electron-emitting device as the electron-emitting device, it is possible to configure a large-sized electron beam generator with a low power consumption and a high response speed. Among them, in particular, the surface conduction electron-emitting device has a simple structure and a large number of devices can be easily arranged. An electron beam generator can be achieved.

Further, a plurality of surface conduction electron-emitting devices are arranged in a two-dimensional matrix and are connected by a plurality of row-direction wirings and a plurality of column-direction wirings, respectively. By providing an appropriate drive signal in the direction, a large number of surface conduction electron-emitting devices can be selected and the amount of electron emission can be controlled. It can be easily configured on a single substrate.

Since the image forming apparatus of the present invention uses the electron beam generating apparatus of the present invention, as described above, the trajectory of electrons is stable, and a good image with no light emission position shift can be formed. Become. In particular, by using a surface conduction electron-emitting device as the electron-emitting device, an image forming apparatus with a simple structure and a large screen can be achieved.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view of a first embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a schematic sectional view of the image forming apparatus shown in FIG.

FIG. 3 is a plan view of a main part of an electron source of the image forming apparatus shown in FIG.

FIG. 4 is a sectional view taken along line AA ′ of the electron source shown in FIG. 3;

FIG. 5 is a view sequentially illustrating a manufacturing process of the electron source of the image forming apparatus illustrated in FIG. 1;

FIG. 6 is a plan view of an example of a mask used when forming a thin film for forming an electron-emitting portion.

FIG. 7 is a diagram showing an example of a voltage waveform used for forming processing.

FIG. 8 is a diagram illustrating a configuration of a fluorescent film.

FIG. 9 is a schematic sectional view of a second embodiment of the image forming apparatus of the present invention.

FIG. 10 is a schematic sectional view of a third embodiment of the image forming apparatus of the present invention.

FIG. 11 is a schematic configuration diagram of a conventional image forming apparatus using a thermionic electron source.

FIG. 12 is a schematic configuration diagram showing a partially enlarged conventional image forming apparatus using a field emission type electron source.

FIG. 13 is a diagram showing a typical device configuration of a surface conduction electron-emitting device.

FIG. 14 is a schematic sectional view of a conventional image forming apparatus using a surface conduction electron-emitting device.

[Explanation of symbols]

 1, 51, 101 Electron source 2, 52, 102 Rear plate 3, 53, 103 Face plate 4, 54, 104 Support frame 6, 56, 106 Glass substrate 7 Phosphor film 7a Phosphor 8, 58, 108 Metal back 9 Conduction Film 10 Enclosure 11 Insulating substrate 12 X-direction wiring 13 Y-direction wiring 14 Interlayer insulating layer 14a Contact hole 15, 65, 115 Electron-emitting device 16, 17 Device electrode 18 Thin film for forming electron-emitting portion 20 Mask 20a Opening 21 Cr Film 23 electron emitting portion 105 wall-shaped electrode

Continuation of the front page (56) References JP-A-1-298624 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 31/12

Claims (8)

(57) [Claims] 1. A plurality of row-direction wirings and a plurality of column-direction wirings
Accordingly, a plurality of connected electron-emitting devices are arranged in a matrix and an electron source is arranged in a vacuum atmosphere to irradiate electrons emitted from the electron-emitting devices in a vacuum atmosphere. the electron beam generating apparatus having a substrate with <br/> having an electron irradiated member having an acceleration electrode for accelerating the emitted electrons from, as viewed from the electron-emitting portion of said plurality of electron-emitting devices, When an angle with respect to a direction perpendicular to the plane of the electron source is θ,
At least tan of a surface of the substrate facing the electron source;
An electron beam generator characterized in that members within the entire range satisfying θ ≦ 2 are regulated in potential. 2. A support frame forming a part of an envelope for maintaining a vacuum atmosphere between the electron source and the electron-irradiated member, wherein an inner surface of the electron-irradiated member and the support frame 2. The electron beam generator according to claim 1, wherein a conductive film electrically connected to the acceleration electrode is formed on an inner surface, so that the conductive film forms a member within the range. 3. 3. When the facing distance between the electron-emitting device and the electron-irradiated member is d, a position of the electron-irradiated member between the electron-emitting device and the electron source from a position facing the electron-emitting portion of the electron-emitting device. 2. The electron beam generator according to claim 1, wherein the acceleration electrode is formed in at least a range of 2 d in any direction on the facing surface, so that the acceleration electrode forms a member in the range. 3. . 4. The acceleration electrode and the wall are formed by forming a wall-shaped electrode electrically connected to the acceleration electrode and protruding toward the electron source on an outer periphery of the electron irradiation member. The electron beam generator according to claim 1, wherein a member within the range is formed by the shape electrode. 5. The electron beam generator according to claim 1, wherein the electron-emitting device is a cold cathode type electron-emitting device. 6. The electron beam generator according to claim 5, wherein said cold cathode type electron-emitting device is a surface conduction type electron-emitting device. 7. A plurality of said surface conduction electron-emitting devices are arranged in a two-dimensional matrix, and each of said surface conduction electron-emitting devices is constituted by a plurality of row-direction wirings and a plurality of column-direction wirings. 7. The electron beam generator according to claim 6, wherein the electron beam generators are connected. 8. An image forming apparatus using the electron beam generator according to claim 1, wherein the image forming apparatus is arranged to face the electron source instead of the electron irradiation member, An image forming apparatus comprising: a phosphor that emits light when electrons emitted from an electron-emitting device collide with each other; and an image-forming member including an acceleration electrode for accelerating the electrons emitted from the electron-emitting device.