JP3372731B2 - Image forming device - 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-emitting device, and more particularly to an image forming apparatus using a surface conduction electron-emitting device.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitters, a thermoelectron source and a cold cathode electron source, are known. The cold cathode electron source includes a field emission type (hereinafter abbreviated as FE type), a metal / insulating layer / metal type (hereinafter abbreviated as MIM type), a surface conduction type electron emitting device, and the like. Examples of FE type are WP Dyke & WWD
olan, "Field emission", Advance in Electron Physic
is, 8 89 (1956) or CASpindt, “Physical Pro
perties of thin-film field emission cathodes with
molybdenium ", J.Appl.Phys., 47 5248 (1976), etc. An example of the MIM type is CAMead," The tunnel-
emission amplifier ", J. Appl. Phys., 32 646 (1961)
Etc.

An example of the surface conduction electron-emitting device is MIElin.
Son, Radio Eng. Electron Phys., 10 (1965) and the like. This surface conduction electron-emitting device utilizes a phenomenon in which electrons are emitted by causing a current to flow in a thin film having a small area formed on a substrate in parallel with the film surface. This element uses a SnO ₂ thin film by Erinson et al., And an Au thin film [G. Dittmer: "Thin
Solid Films, 9 317 (1972)], In ₂ O ₃ / SnO ₂
Thin film [M.Hartwell and CGFonstad: "IEEE
Trans. ED Conf. ", 519 (1975)], by carbon thin film [Hiraki Araki et al .: Vacuum, Vol. 26, No. 1, p. 22 (1)
983)] and the like have been reported.

As a typical device configuration of these surface conduction electron-emitting devices, the above-mentioned M. The Hartwell device configuration is shown in FIG. In the figure, 201 is a substrate. Two
Reference numeral 04 is a conductive thin film, which is formed into an H-shaped pattern by a metal oxide thin film formed by sputtering or the like, and the electron emission portion 205 is formed by an energization process called energization forming described later. The distance L between the device electrodes in the figure is set to 0.5 to 1 mm, and W'is set to 0.1 mm. The position and shape of the electron emitting portion 205 are not shown exactly, so they are shown schematically.

This energization forming means a conductive thin film 2
A direct current voltage or a very slow rising voltage (for example, about 1 V / min) is applied to both ends of 04 to energize the conductive thin film 204 to locally destroy, deform, or alter the conductive thin film 204 to be in an electrically high resistance state. That is, the electron emitting portion 205 is formed. When a voltage is applied to the conductive thin film 204 of the surface conduction electron-emitting device that has been subjected to the energization forming process and a current is caused to flow through the device, electrons are emitted from the vicinity of the crack formed in a part of the conductive thin film 204.

This surface conduction electron-emitting device has an advantage that a large number of devices can be arrayed over a large area because the structure is simple and the manufacture is easy. Thus, for example, a charged beam source,
Various applications such as an image display device that make the best use of this feature have been studied. In the image forming apparatus using the electron-emitting device, an image can be formed by accelerating the electrons generated in the electron-emitting device by an accelerating voltage and irradiating the phosphor provided on the face plate.

[0007]

In such an image forming apparatus, particularly in the case of the electron source substrate in which the electron-emitting devices are densely arranged, heat is generated by passing a current through the electron-emitting devices. As a result, a temperature gradient is generated in the device, thermal expansion occurs, and in some cases image color misregistration occurs. Further, in order to prevent the apparatus from being adversely affected by the thermal stress due to this temperature gradient, the rigidity of the image forming apparatus has been increased in the prior art by means such as thickening the constituent members. As a result, the conventional image forming apparatus is relatively heavy.

The present invention has been made in view of the problems of the prior art as described above, and in an image forming apparatus using an electron-emitting device (particularly, a surface conduction electron-emitting device), heat generated by an electron source substrate is efficiently converted. An object of the present invention is to provide an image forming apparatus capable of radiating heat quickly and well, making the temperature distribution in the electron source substrate uniform, preventing color misregistration of an image, and further reducing the weight.

[0009]

The above object of the present invention is to provide an electron source substrate having at least an electron-emitting device, and an object to be irradiated which is arranged to face the electron source substrate and receives electrons emitted from the electron-emitting device. An image forming apparatus having a face plate on which a member is mounted is arranged on a surface of the electron source substrate opposite to a surface having the electron emitting element.
Through the conductive film layer and the conductive film layer and the heat conductive elastic layer.
This can be achieved by an image forming apparatus characterized by having a heat radiation plate thermally connected .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, preferred embodiments of the present invention will be described.

FIG. 1 is a perspective view showing an image forming panel as one embodiment of the image forming apparatus of the present invention. In FIG. 1, reference numeral 1 is an electron source substrate on which device electrodes, electron-emitting devices and the like (not shown) are mounted. Reference numeral 2 is a phosphor or the like (not shown) which is a member to be irradiated which receives electrons emitted from the electron-emitting device.
Is a face plate having an image forming area 7 in the center thereof, which is an area for forming an image by the emission of the phosphor. Reference numeral 3 is a support frame, 4 is a sealing frit, 5 is an envelope formed by the electron source substrate 1, the face plate 2, the support frame 3 and the sealing frit 4, and 6 is an electron source substrate 1.
The conductive film layer provided on the surface opposite to the surface having the electron-emitting device (that is, the back surface), 7 is a heat dissipation plate having an enlarged heat dissipation surface 7 ′, and 8 is between the conductive film layer 6 and the heat dissipation plate 7. Is a heat conductive elastic layer interposed in the. FIG. 2 is an enlarged schematic cross-sectional view showing the conductive film layer 6 and the like provided on the back surface of the electron source substrate 1.

This image forming apparatus can be manufactured as follows. First, the electron source substrate 1, the face plate 2, the support frame 3, and the sealing frit 4 are fixed by a fixing jig (not shown) and baked and sealed at a predetermined temperature to manufacture the envelope 5. Then, the conductive film layer 6 is formed on the back surface of the electron source substrate 1 by a desired film forming method. Next, the heat conductive elastic layer 8 is fitted to the conductive film layer 6, and the heat sink 7 is further adhered thereto.

A typical example of the conductive film layer 6 is a metal plating film, but the conductive film layer 6 is not limited to this and can be formed by any method such as electrolytic or electroless plating, vacuum film formation, vapor deposition, and sputtering. Can be a membrane. From the viewpoint of thermal conductivity and specific gravity, the constituent material of the conductive film layer 6 is preferably nickel, copper, aluminum, silver, gold or the like. In particular, an electroless nickel plating film, an electroless copper plating film, an electroless composite plating film, a vapor deposition copper film and the like can be preferably used. Moreover, you may make it a multilayer structure. The thickness of the conductive film layer 6 is preferably about 1 μm to 500 μm, more preferably about 10 μm to 500 μm.

Further, when soda lime glass is used as the electron source substrate 1 and a metal plating film is used as the conductive film layer 6, it is advantageous in that the manufacturing cost is low and the film thickness is easy.

By providing such a conductive film layer 6 on the back surface of the electron source substrate 1, it functions as a heat dissipation structure that does not require a space. That is, the heat generated by the electron-emitting device can be quickly conducted into the surface of the electron source substrate 1, and the temperature can be made uniform. Furthermore, the efficiency of heat dissipation is also improved. As a result, the color shift of the image can be prevented, the device can be made thinner than the conventional device, and the space occupied by the heat radiating means is small. Therefore, the device can be made lighter and thinner. Further, in the embodiment shown in FIG. 1, since the heat conductive elastic layer 8 is interposed between the conductive film layer 6 and the electron source substrate 1, no gap is generated even if displacement such as warpage due to heat occurs. It also has the advantage of not lowering heat transfer. Further, a heat dissipation plate 7 that is further thermally connected to the conductive film layer 6
Therefore, the uniform air temperature and the improvement of the heat radiation efficiency are further promoted by the natural air cooling of the large number of fin-shaped enlarged heat radiation surfaces 7 '.

The heat conductive elastic layer 8 can be used without particular limitation as long as it is a layer having both heat conductivity and elasticity. For example, a processed rubber product for heat dissipation (heat conductive rubber) that is commercially available is suitable. In addition to this, the same effect can be obtained by using, for example, heat conductive grease.

The shape and number of the heat radiating plate 7 and the enlarged heat radiating surface 7'is also one of the suitable examples shown in FIG. 1, but is not particularly limited, and the above-mentioned uniform temperature of the enlarged heat radiating surface, Various modifications are possible within a range in which a desired effect such as improvement of heat dissipation efficiency can be obtained. In particular, the fin-shaped enlarged heat-dissipating surface 7 ′ of this heat-dissipating plate 7 is substantially parallel to the gravity when the image forming apparatus is used so that heat dissipation by natural convection is favorably performed. It is good to install it. In particular, it is preferable that the form of heat dissipation by natural convection is possible and forced air cooling is unnecessary.

FIG. 3 is a perspective view showing another embodiment of the present invention. In FIG. 3, 9 is a film-shaped metal film obtained by rolling a metal, and 10 is a heat dissipation plate having an enlarged heat dissipation surface 10 ′ provided on the side surface of the panel. The same members as those in FIG. 1 are designated by the same reference numerals. In this image forming apparatus, as described above, the envelope 5 is manufactured, the conductive film layer 6 is formed, and the heat dissipation plate 10 having the enlarged heat dissipation surface 10 ′ is provided on the side surface of the panel. 6 can be manufactured by connecting the heat sink 10 with the film-shaped metal film 9.

The shape and number of the heat dissipation plate 10 and the enlarged heat dissipation surface 10 'provided on this side surface can be variously modified as desired, like the heat dissipation plate 7 and the enlarged heat dissipation surface 7'shown in FIG. In addition, the film-shaped metal film 9 includes the conductive film layer 6 and the heat sink 1.
There is no particular limitation as long as it is a film capable of thermally connecting 0, and various metals such as an aluminum rolled film and a copper rolled film can be preferably used.

In the embodiment shown in FIG. 3, the electron source substrate 1
The heat generated in 1 is conducted by the conductive film layer 6 so that the temperature distribution in the electron source substrate 1 becomes uniform, and at the same time, conducted through the film-shaped metal film 9 to the heat dissipation plate 10 provided on the side surface of the panel. In particular, it is naturally air-cooled by the enlarged heat radiation surface 10 '.

Another aspect of the present invention is a gas discharge type image forming apparatus. The manufacturing method will be briefly described below. First, the discharge plasma electrode and the electron extraction electrode are arranged on the back plate. Further, a control electrode composed of a band-shaped electrode group provided on a plate-shaped insulating substrate is arranged. After that, the face plate provided with the fluorescent film is arranged and sealed so as to face the extraction electrode in parallel. Then, the inside of the image forming apparatus is evacuated and a rare gas having a low atmospheric pressure is filled, so that the gas discharge type image forming apparatus can be manufactured. Similar effects can be obtained even in such a mode.

In the present invention, a surface conduction electron-emitting device is particularly suitable as the electron-emitting device mounted on the electron source substrate 1. The surface conduction electron-emitting device will be described below. There are basically two types of surface-conduction electron-emitting devices: a planar surface-conduction electron-emitting device and a vertical surface-conduction electron-emitting device. FIG. 4 is a diagram showing the structure of a basic surface conduction electron-emitting device.
Is a schematic plan view, and (b) is a sectional view thereof. In FIG. 4, 201 is a substrate, 202 and 203 are element electrodes, 2
Reference numeral 04 is a conductive thin film, and 205 is an electron emitting portion.

As the substrate 201, quartz glass, glass containing a small amount of impurities such as Na, soda lime glass, SiO ₂
A glass substrate and a ceramics substrate made of alumina or the like having the surface thereof formed thereon are used. A general conductor is used as the material of the device electrodes 202 and 203, and for example, Ni or C is used.
Metals or alloys such as r, Au, Mo, W, Pt, Ti, Al, Cu, Pd, and Pd, Ag, Au, RuO ₂ , P
It is appropriately selected from a printed conductor composed of a metal such as d-Ag or a metal oxide and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ and a semiconductor material such as polysilicon.

The element electrode spacing L is preferably several thousand angstroms to several hundreds of micrometers. Further, it is desirable that the voltage applied between the device electrodes is low, and it is required to manufacture the device with good reproducibility. Therefore, the preferred device electrode interval is 1 μm to 100 μm.

The device electrode length W is preferably several micrometers to several hundreds of micrometers in view of the resistance value of the electrodes and electron emission characteristics, and the film thickness of the device electrodes 202 and 203 is
A few hundred angstroms to a few micrometers are preferred.

In addition to the structure shown in FIG. 4, for example, a conductive thin film 204, element electrodes 202 and 203 are formed on a substrate 201.
The electrodes may be sequentially formed.

The conductive thin film 204 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The thickness of the conductive thin film 204 is step coverage to the device electrodes 202 and 203, and between the device electrodes 202 and 203. The resistance is appropriately set according to the resistance value and the energization forming conditions described later, but is preferably several angstroms to several thousand angstroms, particularly preferably 10 angstroms to 5 angstroms.
It is 00 angstrom. The sheet resistance is 10
^{3 to} 10 ⁷ ohm / square.

The material forming the conductive thin film 204 is
Pd, Pt, Ru, Ag, Au, Ti, In, Cu, C
Metals such as r, Fe, Zn, Sn, Ta, W and Pd, Pd
O, SnO ₂ , In ₂ O ₃ , PdO, Sb ₂ O _{3 and} other oxides, HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB
₄ , boride such as GdB ₄ , TiC, ZrC, HfC, T
Carbides such as aC, SiC, WC, Tin, ZrN, Hf
Examples thereof include nitrides such as N, semiconductors such as Si and Ge, and carbon.

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and its fine structure is not only in the state where the fine particles are individually dispersed and arranged but also in the state where the fine particles are adjacent to each other or overlap each other (island). The particle size of the fine particles is several angstroms to several thousand angstroms, preferably 10 angstroms to 200 angstroms.

The electron emitting portion 205 is a high resistance crack formed in a part of the conductive thin film 204, and is formed by energization forming or the like. In addition, the conductive particles having a particle diameter of several angstroms to several hundred angstroms may be contained in the cracks. The conductive fine particles are the conductive thin film 2
04 contains at least a part of the constituent substances. In addition, the electron-emitting portion 205 and the conductive thin film 2 in the vicinity thereof
04 may also contain carbon and carbon compounds.

FIG. 5 is a schematic sectional view showing the structure of a basic vertical surface conduction electron-emitting device. In FIG. 5, reference numeral 221 denotes a step forming portion, and the same members as those in FIG.

The substrate 201, the device electrodes 202 and 203, the conductive thin film 204, and the electron emitting portion 205 can be made of the same materials as those of the above-mentioned plane type surface conduction electron emitting device. The step forming portion 221 is made of an insulating material, and the film thickness of the step forming portion 221 corresponds to the element electrode distance L of the flat surface conduction electron-emitting device in FIG. 4 described above. The distance is several hundred angstroms to several tens of micrometers. The distance can be controlled by the manufacturing method of the step forming portion 221 and the voltage applied between the element electrodes, but is preferably several hundred angstroms to several micrometers.

The conductive thin film 204 is used for the device electrodes 202, 2
03 and the step forming portion 221 are formed after they are formed, so that they are laminated on the device electrodes 202 and 203. In FIG. 5, the electron emitting portion 205 is shown to be linearly formed in the step forming portion 221, but the shape and position are not limited to this, depending on the manufacturing conditions, energization forming conditions, and the like. is not.

Various methods are conceivable as a method for manufacturing the surface conduction electron-emitting device of FIG. 4 described above, and one example thereof will be described with reference to FIG. 6, the same members as those in FIG. 4 are designated by the same reference numerals.

1) After thoroughly cleaning the substrate 201 with a detergent, pure water and an organic solvent, a device electrode material is deposited by a vacuum deposition method, a sputtering method or the like. After that, patterning is performed by a photolithography technique to form device electrodes 202 and 203 on this substrate 201 [FIG. 6 (a)].

2) An organic metal thin film is formed by coating an organic metal solution on the substrate 201 having the device electrodes 202 and 203 and leaving it to stand. The organometallic solution referred to here is a solution of an organometallic compound containing a metal forming the conductive thin film 204 as a main element. After that, the organic metal thin film is heated and baked, and is patterned by using a known technique such as lift-off and etching to form the conductive thin film 204 [FIG. 6 (b)]. It should be noted that although the description has been given here by using the coating method of the organic metal solution, the present invention is not limited to this, and it may be formed by a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like. Good.

3) Subsequently, energization processing called energization forming is performed. The energization forming is performed by the device electrode 202,
Power is supplied from a power source (not shown) to the conductive thin film 203.
04 is locally destroyed, deformed or altered to form a site having a changed structure. The site where the structure is locally changed is called an electron emission unit 205 [FIG.
(C)].

FIG. 7 shows an example of a voltage waveform of energization forming. A pulse waveform is particularly preferable as the voltage waveform, and when a voltage pulse having a constant pulse peak value is continuously applied [Fig.
(A)] and the case of applying a voltage pulse while increasing the pulse peak value [FIG. 7 (b)].

First, the case where the pulse peak value is a constant voltage [FIG. 7 (a)] will be described. In FIG. 7A, T1 and T2 are the pulse width and pulse interval of the voltage waveform. T1 is set to 1 microsecond to 10 milliseconds, T2 is set to 10 microseconds to 100 milliseconds, and the peak value of the triangular wave (peak voltage during energization forming) is appropriately selected according to the form of the surface conduction electron-emitting device. Vacuum degree, eg 10 ^-5
It is applied for several seconds to several tens of minutes in a vacuum atmosphere of about torr. The waveform applied between the electrodes of the element is not limited to the triangular wave, and a desired waveform such as a rectangular wave may be used.

T1 and T2 in FIG. 7B are shown in FIG.
Similar to (a), the crest value of the triangular wave (peak voltage during energization forming) is increased by, for example, about 0.1 V step and applied in an appropriate vacuum atmosphere. In the energization forming in this case, the element current is measured at a voltage that does not locally break or deform the conductive thin film 204 during the pulse interval T2, for example, a voltage of about 0.1 V, and the resistance value is obtained. The energization forming is completed when the resistance is higher than ohms.

4) Next, it is desirable to perform a process called an activation process on the element which has completed the energization forming. The activation process is, for example, a process of repeatedly applying a voltage pulse having a constant pulse peak value at a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁵ torr, similarly to the energization forming, and an organic substance existing in a vacuum. Is a process of depositing carbon and a carbon compound resulting from the above on the conductive thin film to remarkably change the device current If and the emission current Ie. The activation process is ended, for example, when the emission current Ie is saturated while measuring the device current If and the emission current Ie. Further, it is preferable that the voltage pulse to be applied is an operation drive voltage. Here, carbon and carbon compound are graphite (both single and polycrystalline),
Amorphous carbon (refers to a mixture of amorphous carbon and polycrystalline graphite), and its film thickness is preferably 500 angstroms or less, and more preferably 300 angstroms or less.

5) It is desirable that the electron-emitting device thus manufactured is driven and operated in an atmosphere having a vacuum degree higher than the vacuum degree in the energization forming step and the activation step. In an atmosphere of a higher vacuum degree, 80 ° C ~
It is preferable to operate after heating at 150 ° C. Here, the vacuum degree higher than the vacuum degree subjected to the energization forming step and the activation treatment is, for example, a vacuum degree of about 10 ⁻⁶ or more,
The ultra-high vacuum system is more preferable, and the degree of vacuum is such that new carbon and carbon compounds are hardly deposited on the conductive thin film. By doing so, the device current If and the emission current Ie can be stabilized.

FIG. 8 is a schematic block diagram showing an example of a measurement / evaluation apparatus for measuring the electron emission characteristic of the element having the structure shown in FIG. In FIG. 8, the same symbols as those in FIG. 4 indicate the same things. Further, 251 is a power source for applying the device voltage Vf to the electron-emitting device, and 250 is the device electrode 2
A device current I flowing through the conductive thin film 204 between 02 and 203
An ammeter for measuring f, 254 is an anode electrode for capturing the emission current Ie emitted from the electron emission portion 205 of the element, 253 is a high voltage power source for applying a voltage to the anode electrode 254, and 252 is an element. Of the electron emission unit 205
An ammeter for measuring the emission current Ie emitted by
255 is a vacuum device and 256 is an exhaust pump.

Next, the image forming apparatus of the present invention will be described.

The electron source substrate used in the image forming apparatus is
For example, it is formed by arranging a plurality of surface conduction electron-emitting devices on a substrate. The arrangement method of the surface conduction electron-emitting devices is to arrange the surface conduction electron-emitting devices in parallel and connect both ends of each element with wiring in a ladder arrangement (hereinafter referred to as a ladder arrangement electron source substrate) or , Wiring in the X direction on a pair of device electrodes of the surface conduction electron-emitting device,
A simple matrix arrangement in which wirings in the Y direction are connected (hereinafter referred to as matrix type arrangement electron source substrate) can be given. An image forming apparatus having a ladder type electron source substrate requires a control electrode (grid electrode) which is an electrode for controlling the flight of electrons from the electron-emitting device.

A simple matrix type arrangement electron source substrate constructed on the basis of this principle will be described below with reference to FIG. In FIG. 9, 271 is an electron source substrate, 272 is an X-direction wiring, 273 is a Y-direction wiring, 274 is a surface conduction electron-emitting device, and 275 is a connection. The surface conduction electron-emitting device 274 may be either the flat type or the vertical type described above. The substrate used for the electron source substrate 271 is the above-mentioned glass substrate or the like, and the shape is appropriately set according to the application.

The m X-direction wirings 272 are Dx1 and Dx.
2, ..., Dxm, and the Y-direction wiring 273 is
It consists of n wirings Dy1, Dy2, ..., Dyn. Further, the material, the film thickness, and the wiring width are appropriately set so that a substantially uniform voltage is supplied to many surface conduction electron-emitting devices 274. The m number of X-direction wirings 272 and the n number of Y-direction wirings 273 are electrically separated by an interlayer insulating layer (not shown) to form a matrix wiring (m, n).
Are both positive integers). The interlayer insulating layer (not shown) is formed in a desired region on the entire surface or a part of the substrate 271 on which the X-direction wiring 272 is formed. The X-direction wiring 272 and the Y-direction wiring 273 are drawn out as external terminals. Further, the device electrodes (not shown) of the surface conduction electron-emitting device 274 are composed of m X-direction wirings 272 and n Y-direction wirings 2.
73 and the connection wire 275.
The surface conduction electron-emitting device 274 may be formed either on the substrate or on an interlayer insulating layer (not shown).

The X-direction wiring 272 will be described in detail later.
Are electrically connected to a scanning signal generating means (not shown) for applying a scanning signal for scanning the row of the surface conduction electron-emitting devices 274 arranged in the X direction according to the input signal. On the other hand, the Y-direction wiring 273 is electrically connected to a modulation signal generating means (not shown) for applying a modulation signal for modulating each row of the surface conduction electron-emitting devices 274 arranged in the Y direction according to an input signal. It is connected to the.

Further, the drive voltage applied to each element of the surface conduction electron-emitting device 274 is supplied as a difference voltage between the scanning signal applied to the element and the modulation signal. In such a configuration, individual elements can be selected and driven independently by simple matrix wiring.

Next, an image forming apparatus using this matrix type arrangement electron source substrate will be described with reference to FIGS. 10, 11 and 1.
2 is used for the explanation. FIG. 10 is a basic configuration diagram of the image forming apparatus, FIGS. 11A and 11B are diagrams showing an example of the configuration of the fluorescent film, and FIG. 12 is a diagram for displaying in accordance with an NTSC television signal. It is a drive circuit block diagram.

In FIG. 10, reference numeral 271 denotes an electron source substrate on which an electron-emitting device is formed, and 281 denotes an electron source substrate 27.
1 is fixed to the rear plate 286 is a glass substrate 283
A face plate having a fluorescent film 284, a metal back 285 and the like formed on the inner surface thereof is a support frame 282, and these members constitute an envelope 288. Reference numeral 276 corresponds to the electron emitting portion 205 in FIG. 272, 27
Reference numeral 3 is an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device.

The envelope 288 is composed of the face plate 286, the support frame 282, and the rear plate 281 as described above. The rear plate 281 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 271. Source board 27
If the one itself has sufficient strength, a separate rear plate 28
1 is unnecessary. That is, the support frame 282 is provided directly on the electron source substrate 271, and the face plate 286 and the support frame 2 are provided.
82 and the electron source substrate 271 may constitute the envelope 288.

Fluorescent film 284 of face plate 283
Is shown in detail in FIG. In FIG. 11, 292 is a phosphor and 291 is a black conductive material.
In the case of monochrome, the phosphor 292 is composed of only the phosphor, but in the case of a color phosphor film, it is composed of a black conductive material 291 called a black stripe or a black matrix depending on the arrangement of the phosphor and a phosphor 292.
The purpose of providing the black stripes and the black matrix is to make the mixed colors and the like inconspicuous by making the coating portions between the phosphors 292 of the three primary color phosphors necessary for color display inconspicuous, and in the phosphor film 284. This is to suppress a decrease in contrast due to reflection of external light. As the material of the black stripe, not only the material that is commonly used as a main component of graphite, but also conductive,
The material is not limited to this as long as the material transmits and reflects light little. The method of applying the phosphor to the glass substrate 283 may be a precipitation method or a printing method regardless of monochrome or color.

A metal back 285 (FIG. 10) is usually provided on the inner surface side of the fluorescent film 284 (FIG. 10). The purpose of the metal back 285 is to make the component of the light, which is directed toward the inner surface side, out of the luminescent components of the phosphor, the face plate 286.
It is possible to improve brightness by specular reflection to the side, to act as an electrode for applying an electron beam acceleration voltage, and to protect the phosphor from damage due to collision of negative ions generated in the envelope 288. is there. Metal back 2
85 can be manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 284 after manufacturing the fluorescent film 284, and then depositing Al (aluminum) by a vacuum deposition method or the like.

Further, on the electron source substrate 271,
The conductive film layer 6 and the like as shown in FIGS. 1 and 2 are provided.

The inside of the envelope 288 is evacuated through an exhaust pipe (not shown), and a vacuum degree of about 10 ^-7 torr is obtained and sealed. In addition, a getter process may be performed in order to maintain the degree of vacuum after the envelope 288 is sealed. This is performed by a heating method such as resistance heating or high-frequency heating immediately before or after sealing the envelope 288.
This is a process of heating a getter previously placed at a predetermined position (not shown) in 88 to form a vapor deposition film on the inner surface of the envelope. The getter usually has Ba or the like as a main component, and is, for example, 1 × 10 ⁻⁵ torr to 1 × 1 due to the adsorption action of the deposited film.
The degree of vacuum is maintained at 0 ^-7 torr. The steps after the forming of the surface conduction electron-emitting device are appropriately set.

Next, in the image forming apparatus constituted by using the matrix type arrangement electron source substrate, the schematic constitution of the drive circuit for performing the television display based on the television signal of the NTSC system is shown in the block diagram of FIG. Explain.
In FIG. 12, 301 is an image forming apparatus (display panel).
, 302 is a scanning circuit, 303 is a control circuit, 304
Is a shift register, 305 is a line memory, 306 is a sync signal separation circuit, 307 is a modulation signal generator, Vx and V
a is a DC voltage source.

The function of each unit will be described below. The image forming apparatus 301 includes terminals Dox1 to Doxm and a terminal Doy.
1 to Doyn and the high voltage terminal Hv are connected to an external electric circuit. Of these, terminals Dox1 to Doxm
Is a scanning signal for sequentially driving an electron source provided in the image forming apparatus 301, that is, a group of surface conduction electron-emitting devices which are matrix-wired in a matrix of M rows and N columns row by row (N elements). Is applied. On the other hand, a modulation signal for controlling the output electron beam of each element of the surface conduction electron-emitting devices of one row selected by the scanning signal is applied to the terminals Dy1 to Dyn. A DC voltage source Va supplies a DC voltage of, for example, 10 [kV] to the high-voltage terminal Hv, which is sufficient to excite the phosphor into the electron beam output from the surface conduction electron-emitting device. It is an accelerating voltage for applying various energies.

Next, the scanning circuit 302 will be described.
The circuit includes M switching elements inside thereof (schematically shown by S1 to Sm in the figure), and each switching element is an output voltage of the DC voltage source Vx or 0.
One of [V] (ground level) is selected and electrically connected to the terminals Dx1 to Dxm of the display panel 301. Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 303, but can actually be configured by combining switching elements such as FETs. The direct-current voltage power supply Vx is a constant voltage such that the drive voltage applied to an unscanned element based on the characteristics of the surface conduction electron-emitting device (electron emission threshold voltage) becomes equal to or lower than the electron emission threshold voltage. Is set to output.

The control circuit 303 has a function of matching the operation of each part so that an appropriate display is performed based on the image signal input from the outside. Then, based on the synchronization signal Tsync sent from the synchronization signal separation circuit 306 described below, Tscan, Tsft, and Tm are supplied to the respective units.
Each ry control signal is generated.

The sync signal separation circuit 306 is a circuit for separating the sync signal component and the luminance signal component from the NTSC system television signal input from the outside, and can be constructed by using a frequency separation (filter) circuit. The sync signal separated by the sync signal separation circuit 306 is composed of a vertical sync signal and a horizontal sync signal as is well known, but is shown here as a Tsync signal for convenience of description. On the other hand, the luminance signal component of the image separated from the television signal is DA for convenience.
Although referred to as a TA signal, this signal is input to the shift register 304.

The shift register 304 is for converting the DATA signals serially input in time series into serial / parallel conversion for each line of the image, and the control circuit 3
It operates on the basis of the control signal Tsft sent from H.03. That is, the control signal Tsft is output to the shift register 3
In other words, the shift clock is 04. The data of one line of the serial / parallel-converted image (corresponding to the driving data of N electron-emitting devices) is Id.
Shift register 3 as N parallel signals 1 to Idn
It is output from 04.

The line memory 305 is a storage device for storing data for one line of an image only for a required time, and appropriately stores the contents of Id1 to Idn according to the control signal Tmry sent from the control circuit 303. . The stored contents are output as Id'1 to Id'n,
It is input to the modulation signal generator 307.

The modulation signal generator 307 outputs the image data I
A signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices according to each of d'1 to Id'n, the output signal of which is output from the surface conduction type in the display panel 301 through terminals Doy1 to Doyn. It is applied to the electron-emitting device.

The electron-emitting device according to the present invention has the following basic characteristics with respect to the emission current Ie. That is,
There is a clear threshold voltage Vth for electron emission, and Vth
Electrons are emitted only when the above voltage is applied. Further, for a voltage equal to or higher than the electron emission threshold value, the emission current also changes according to the change in the voltage applied to the device. The electron emission threshold voltage Vth and the degree of change of the emission current with respect to the applied voltage may be changed by changing the material, configuration, and manufacturing method of the electron emitting device.
In any case, the following can be said.

That is, when a panel-like voltage is applied to this device, for example, when a voltage below the electron emission threshold is applied, no electron emission occurs, but when a voltage above the electron emission threshold is applied. An electron beam is output to. In that case, firstly, the intensity of the output electron beam can be controlled by changing the peak value Vm of the pulse.
Second, it is possible to control the total amount of charges of the electron beam output by changing the pulse width Pw.

Therefore, as a method of modulating the electron-emitting device according to the input signal, a voltage modulation method, a pulse width modulation method and the like can be mentioned. In the case of implementing the voltage modulation method, a circuit of the voltage modulation method is used as the modulation signal generator 307, which generates a voltage pulse of a fixed length but appropriately modulates the peak value of the pulse according to the input data. .
In the case of implementing the pulse width modulation method, the modulation signal generator 307 generates a voltage pulse having a constant peak value, but a pulse width that appropriately modulates the width of the voltage pulse according to the input data. Modulation circuit is used.

Through the series of operations described above, it is possible to display a television using the image forming apparatus 301 of the present invention as a display panel. Although not particularly described in the above description, the shift register 304 and the line memory 30
5 may be a digital signal type or an analog signal type. The point is that serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.

When the digital signal type is used, it is necessary to convert the output signal DATA of the sync signal separation circuit 306 into a digital signal, which can be achieved by providing an A / D converter at the output section of 306. . Further, in connection with this, the circuit used in the modulation signal generator 307 is slightly different depending on whether the output signal of the line memory 305 is a digital signal or an analog signal.

First, the case of digital signals will be described. In the voltage modulation method, for the modulation signal generator 307, for example, a well-known D / A conversion circuit may be used, and an amplification circuit or the like may be added if necessary. In the case of the pulse width modulation method, the modulation signal generator 307 includes, for example, a high-speed oscillator and a counter for counting the number of waves output from the oscillator, and a comparison for comparing the output value of the counter with the output value of the memory. It can be configured by using a circuit in which a device (comparator) is combined. If necessary, an amplifier for voltage-amplifying the pulse-width-modulated modulation signal output from the comparator up to the drive voltage of the surface conduction electron-emitting device may be added.

Next, the case of analog signals will be described.
In the voltage modulation method, for the modulation signal generator 307, for example, a well-known amplifier circuit using an operational amplifier or the like may be used, and a level shift circuit or the like may be added if necessary. In the case of the pulse width modulation method, for example, a well-known voltage controlled oscillation circuit (VCO) may be used,
An amplifier for performing voltage amplification up to the driving voltage of the surface conduction electron-emitting device may be added if necessary.

In the image forming apparatus completed as described above, each of the electron-emitting devices has terminals outside the container Dox1 to Dox.
Electrons are emitted by applying a voltage through xm and Doy1 to Doyn, and a high voltage is applied to the metal back 285 or the transparent electrode (not shown) through the high voltage terminal Hv to accelerate the electron beam and accelerate the fluorescent film 284. It is possible to display an image by colliding with and exciting and emitting light.

The configuration described above is a schematic configuration necessary for producing a suitable image forming apparatus used for display and the like, and the detailed parts such as the material of each member are not limited to those described above. , Is appropriately selected to suit the application of the image forming apparatus. Also, although the NTSC system is mentioned as the input signal, the input signal is not limited to this, and PAL, SECA
Various methods such as the M method may be used, or a TV signal (for example, a high-definition TV such as the MUSE method) including a plurality of scanning lines may be used.

Next, the above-mentioned ladder type electron source substrate and the image forming apparatus using the same will be described with reference to FIGS. 13 and 14.

In FIG. 13, 310 is an electron source substrate, 3
Reference numeral 11 denotes an electron emitting element, and Dx1 to Dx10 of 312 are common wirings connected to the electron emitting element. A plurality of electron-emitting devices 311 are arranged in parallel in the X direction on the substrate 310 (this is called a device row). A plurality of this element row is arranged on the substrate to form a ladder type electron source substrate. By appropriately applying a drive voltage between the common wirings of each element row, each element row can be independently driven. That is, a voltage equal to or higher than the electron emission threshold value may be applied to the element row that emits the electron beam, and a voltage equal to or lower than the electron emission threshold value may be applied to the element row that does not emit the electron beam. Also, common wirings Dx2 to Dx9 (for example, Dx2 and Dx) between the element rows are provided.
3) may have the same wiring.

FIG. 14 is a schematic block diagram showing an example of the structure of an image forming apparatus provided with a ladder-type electron source. Three
20 is a grid electrode, 321 is a hole through which electrons pass, 322 is an external terminal of Dox1, Dox2, ..., Doxm, and 323 is G1, G2, ... Gn connected to the grid electrode 320. Outer container terminal consisting of 3
Reference numeral 10 denotes an electron source substrate in which the common wiring between each element row is the same wiring as described above. The same reference numerals as those in FIG. 10 indicate the same members. The difference from the image forming apparatus having the simple matrix arrangement (FIG. 10) described above is that the grid electrode 320 is provided between the electron source substrate 310 and the face plate 286.

The grid electrode 320 is capable of modulating the electron beam emitted from the surface conduction electron-emitting device, and the electron beam is applied to the stripe-shaped electrode provided orthogonally to the ladder-shaped element rows. A circular hole 321 is provided for each element so as to pass the element. The shape and installation position of the grid are not necessarily those shown in FIG. 14, and a large number of passage openings may be provided in the form of a mesh as openings, and may be provided, for example, around or near the surface conduction electron-emitting device. . Outer terminal 322
The external terminals 323 of the grid container are electrically connected to a control circuit (not shown).

In this image forming apparatus, a modulation signal for one line of an image is simultaneously applied to the grid electrode column in synchronization with the sequential driving (scanning) of the element rows one column at a time so that each electron beam Control the irradiation to the phosphor and display the image 1
Can be displayed line by line.

Although the image forming apparatus using the surface conduction electron-emitting device has been described above, the present invention is not limited to this, and examples of the electron-emitting device include MIM type electron-emitting devices and field emission type electron-emitting devices. It is also possible to use a cold cathode electron source such as the above, or a thermionic electron source.

The image forming apparatus of the present invention is suitable not only for the above-mentioned television broadcast display device but also for a display device such as a video conference system and a computer. Furthermore, it can be used as an image forming apparatus as an optical printer including a photosensitive drum or the like.

[0081]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 The image forming apparatus shown in FIGS. 1 and 2 was manufactured as follows.

First, a jig (not shown) for fixing the electron source substrate 1, the face plate 2, the support frame 3 and the sealing frit 4 is used.
Then, the envelope 5 was fixed by firing and sealed at a predetermined temperature. The material of the envelope 5 was soda-lime glass. Next, electroless nickel plating was applied over the entire back surface of the electron source substrate 1 to form a conductive film layer 6 having a film thickness of 100 μm. It should be noted that the envelope 5 was covered with a cover in advance so that the plating film was not applied to portions other than the back surface portion of the electron source substrate 1. Then, a heat conductive rubber (trade name TC-20BG, manufactured by Shin-Etsu Silicone Co., Ltd.) was combined with the conductive film layer 6 to form the heat conductive elastic layer 8. Then, on the heat conductive elastic layer 8,
As shown in FIG. 1, a heat radiating plate 7 provided with an enlarged heat radiating surface 7 ′ was closely attached. At the time of this close contact, a holding jig (not shown) was used so that no gap was formed. Further, the image forming apparatus was completed by adding the driving circuit and the like described above.

In the image forming apparatus thus obtained, the heat generated in the electron source substrate 1 is conducted by the conductive film layer 6 and the temperature distribution in the electron source substrate 1 is made uniform, and at the same time, the heat conductive elasticity is obtained. It was conducted to the heat dissipation plate 7 through the layer 8, and was naturally air-cooled by the enlarged heat dissipation surface 7 ', and as a result, there was no color shift of the image due to thermal expansion or the like. Further, it is possible to reduce the weight by reducing the thickness of the structural member.

Example 2 An image forming apparatus was manufactured in the same manner as in Example 1 except that a copper vapor deposition film was formed as the conductive film layer 6 over the entire back surface of the electron source substrate 1 by a vacuum vapor deposition method. did. This image forming apparatus showed the same good temperature distribution and improved heat dissipation efficiency, and there was no image color shift.

Example 3 The image forming apparatus shown in FIG. 3 was manufactured as follows.

First, in the same manner as in Example 1, the envelope 5,
The conductive film layer 6 was provided. Next, a heat dissipation plate 10 having an enlarged heat dissipation surface 10 'is provided on the side surface thereof as shown in the figure, and the conductive film layer 6 and the heat dissipation plate 10 are further connected by using a film metal film (rolled film) 9 of A1. . Conductive layer 6 and heat sink 1
0 and A1 were used for the film metal film 9. Further, the image forming apparatus was completed by adding the driving circuit and the like described above.

The image forming apparatus thus obtained similarly showed uniform temperature distribution, improved heat dissipation efficiency, and there was no color shift in the image.

Example 4 A gas discharge type image forming apparatus (not shown) was manufactured as follows.

First, a discharge electrode for generating discharge plasma was arranged on a glass back plate, and then an electron extraction electrode for extracting electrons from the discharge plasma was arranged. The extraction electrode is made of a metal plate having a large number of regular through holes. Further, a control electrode composed of a strip-shaped electrode group attached on a plate-shaped insulating substrate was arranged. The control electrode has a through hole coaxial with the through hole on the electron extraction electrode so as not to prevent the electrons from going straight. afterwards,
A glass face plate with a fluorescent film attached,
It was arranged in parallel with the extraction electrode formed on the electron source substrate and sealed with a low melting point glass. Then, the inside of the image forming apparatus was evacuated and a rare gas having a low atmospheric pressure was filled therein to manufacture a gas discharge type image forming apparatus. Furthermore, the conductive film layer 6, the heat conductive elastic layer 8, and the same as in Example 1,
The heat sink 7 is provided. Similar effects were obtained also in this image forming apparatus.

[0091]

As described above, according to the present invention,
In an image forming apparatus using an electron-emitting device (particularly a surface conduction electron-emitting device), the temperature inside the electron source substrate can be made uniform, and the heat dissipation effect can be improved, so that color shift of the image due to thermal expansion can be prevented. Further, it is possible to reduce the weight and the thickness of the plate as compared with the conventional device. Therefore, the image forming apparatus of the present invention is very useful as a light-weight, thin plate-shaped image forming apparatus capable of forming a particularly excellent color image.

[Brief description of drawings]

FIG. 1 is a perspective view showing an aspect of an apparatus of the present invention.

FIG. 2 is an enlarged schematic cross-sectional view showing one embodiment of a conductive film layer and the like.

FIG. 3 is a perspective view showing another aspect of the device of the present invention.

4A and 4B are diagrams illustrating the configuration of a basic planar surface conduction electron-emitting device, in which FIG. 4A is a schematic plan view and FIG. 4B is a schematic sectional view thereof.

FIG. 5 is a schematic cross-sectional view illustrating the configuration of a basic vertical surface conduction electron-emitting device.

FIG. 6 is a process drawing showing an example of a method of manufacturing a surface conduction electron-emitting device.

7A and 7B are graphs showing examples of voltage waveforms of energization forming applied to the surface conduction electron-emitting device.

FIG. 8 is a schematic configuration diagram of a measurement / evaluation apparatus used for measuring electron emission characteristics.

FIG. 9 is a schematic diagram showing a configuration example of an electron source substrate having a simple matrix arrangement.

FIG. 10 is a basic configuration diagram showing an example of an image forming apparatus using an electron source substrate having a simple matrix arrangement.

11A and 11B are schematic diagrams showing a configuration example of a fluorescent film of a face plate, respectively.

FIG. 12 is a block diagram showing an example in which a drive circuit for displaying according to an NTSC television signal is incorporated.

FIG. 13 is a schematic view showing a configuration example of an electron source substrate having a ladder arrangement.

FIG. 14 is a basic configuration diagram showing an example of an image forming apparatus using a ladder-type electron source substrate.

FIG. 15 is a configuration diagram of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

1 Electron source substrate 2 face plate 3 support frames 4 Sealing frit 5 envelope 6 Conductive layer 7 Heat dissipation plate with enlarged heat dissipation surface 8 Thermally conductive elastic layer 9 Film metal film 10 Heat dissipation plate with enlarged heat dissipation surface 201 substrate 202 element electrode 203 element electrode 204 Conductive thin film 205 electron emission unit 221 step forming part 250 ammeter 251 power supply 252 ammeter 253 High voltage power supply 254 Anode electrode 255 vacuum device 256 exhaust pump 271 electron source substrate 272 X-direction wiring 273 Y direction wiring 274 surface conduction electron-emitting device 275 connection 276 Electron emission part 281 Rear plate 282 Support frame 283 glass substrate 284 Fluorescent film 285 metal back 286 face plate 288 envelope 291 Black conductive material 292 phosphor 301 Image forming apparatus (display panel) 302 scanning circuit 303 control circuit 304 shift register 305 line memory 306 Sync signal separation circuit 307 Modulation signal generator 310 electron source substrate 311 Electron-emitting device 312 common wiring 320 grid electrode 321 holes for electrons to pass through 322 External terminal 323 External terminal

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Claims (4)

(57) [Claims] 1. An image forming apparatus, comprising: an electron source substrate having at least an electron-emitting device; and a face plate provided with a member to be irradiated which is arranged to face the electron-source substrate and receives electrons emitted from the electron-emitting device. In the device,
A conductive film layer disposed on a surface of the electron source substrate opposite to the surface having the electron-emitting device, and heat conduction with the conductive film layer.
An image forming apparatus comprising: a heat radiating plate thermally connected through a flexible elastic layer . 2. The image forming apparatus according to claim 1, wherein the heat conductive elastic layer is disposed between the conductive film layer and the electron source substrate. Wherein the electron source substrate is soda lime glass, the conductive film layer is an image forming apparatus according to claim 1 or 2 wherein wherein the metal plating film. Wherein said electron-emitting devices in the image forming apparatus of any one of claims 1 to 3 is a surface conduction electron-emitting device.