JP2992927B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates particularly to an image forming apparatus such as a display device or an exposure apparatus comprising an electron source with a cold cathode electron-emitting devices as a driving element.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices, EL display devices, plasma display devices, and the like have been put into practical use as image forming devices, particularly flat display devices, but they are still insufficient in terms of viewing angle, colorization, luminance, and the like. However, the situation has not yet been replaced with a conventional cathode ray tube (CRT).

On the other hand, with the advancement of information processing by computers and the improvement in image quality of television broadcasts, the need for high-definition, large-screen flat display devices is rapidly increasing.

Heretofore, several electron beam-accelerated flat display devices have been proposed for displaying images. For example, U.S. Pat.
935499 and JP-A-56-28445 disclose a control electrode having a flat hot cathode electron source, extracting an electron beam from the electron source, and providing a large number of holes corresponding to phosphor pixels. A flat display device is disclosed in which a group controls and accelerates an electron beam to irradiate a phosphor to emit a desired phosphor pixel.

Attempts have also been made to use a cold cathode electron source instead of the hot cathode electron source as the electron source of the flat display device.

[0006] The cold-cathode type electron-emitting device used as the cold-cathode electron source includes a field emission type (hereinafter referred to as "FE type").
Called. ), Metal / insulating layer / metal type (hereinafter “MIM”)
Type ". ) And surface conduction electron-emitting devices.

As an example of the FE type, W. P. Dyk
e and W. W. Dolan, “Field
emission ", Advance in El
electron Physics, 8, 89 (195
6) or C.I. A. Spindt, “PHYS
ICAL Properties of thin-f
ilm field emission cathod
es with molbdenum cone
s ", J. Appl. Phys., 47, 52.
48 (1976).

As an example of the MIM type, C.I. A. Me
ad, J.M. Appl. Phys. , 32,646
(1961) are known.

As an example of the surface conduction electron-emitting device,
M. I. Elinson, Radio Eng.
Electron Phys. , 10,1290
(1965).

[0010] The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted by passing a current through a small-area conductive thin film formed on an insulating 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. And a device using an Au thin film [G. Dittmer: “ThinS
Solid Films ", 9, 317 (197
2)], an In ₂ O ₃ / SnO ₂ thin film [M.
Hartwell and C.M. G. FIG. Fonsta
d: “IEEE Trans. ED Con
f. , 519 (1975)], and those based on carbon thin films [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, p. 22 (1983)] and the like have been reported.

Heretofore, in these surface conduction electron-emitting devices, an electron-emitting portion has generally been formed on a conductive thin film made of conductive fine particles in advance by an energization treatment called forming. Forming is usually performed by applying a voltage to both ends of the conductive thin film and energizing it.The conductive thin film is locally destroyed, deformed or altered to change its structure, and emits electrons in an electrically high-resistance state. This is a process for forming a part. In the electron emitting portion, a crack is generated in a part of the conductive thin film, and the electron is emitted from the vicinity of the crack.

The above-mentioned surface conduction electron-emitting device has an advantage that a large number of devices can be arranged and formed over a large area because of its simple structure. Therefore, various applications for utilizing this feature are being studied. For example, a charged beam source,
Application to an image forming apparatus such as a display device is exemplified.

Conventionally, as an example in which a large number of surface conduction electron-emitting devices are arrayed, surface conduction electron-emitting devices are arranged in parallel, and both ends (both device electrodes) of each device are interconnected (also referred to as common interconnection). ), An electron source in which a number of rows each connected in () is also arranged (also referred to as a trapezoidal arrangement) (for example, JP-A-64-31332, JP-A-1-283737).
JP-A-2-257552).

In particular, in the case of a display device, a flat panel display device similar to a display device using liquid crystal can be used, and a self-luminous display device that does not require a backlight is used as a surface conduction electron emission device. There has been proposed a display device in which an electron source in which a number of elements are arranged and a phosphor that emits visible light when irradiated with an electron beam from the electron source are combined (US Pat. No. 5,066,883, filed by the present applicant). JP-A-3-261024, etc.).

[0015] All of the display devices described above require vacuum evacuation in the device. In such a display device, a getter process is usually performed to maintain the degree of vacuum in the device. Will be

In general, getters are classified into an evaporable type and a non-evaporable type.

The evaporable getter is a metal tube having a partly opened inside and a vacuum maintaining material such as Ba, Sr or Mg (hereinafter referred to as "getter material") put therein, and has a linear shape. , And ring-shaped ones. The getter material is flashed by induction heating or electric current heating, and the residual gas in the device is adsorbed by the getter material by attaching the getter material to the inner surface of the display, thereby maintaining the degree of vacuum in the device. .

The non-evaporable getter is made of a Zr, V, Fe alloy or the like, and when heated to about 300 ° C. in a vacuum,
It has gas adsorption ability and has the function of maintaining the degree of vacuum in the device.

[0019]

However, the conventional getter process has the following problems.

(1) When the getter material is flashed, if the getter material adheres to the electron source and other control electrode members disposed in the apparatus, the quality of the displayed image is deteriorated. Among the electron sources, cold cathode electron sources, particularly field emission electron emitting devices, and particularly cold cathode electron emitting devices such as surface conduction electron emitting devices, the change in their surface state has a great effect on the electron emission performance. Therefore, the adhesion of the getter material to the element surface has an unfavorable effect.
Therefore, it is necessary to design the installation position of the getter so that the above problem does not occur.

(2) As the area of the display device increases, the internal surface area of the device increases, and in order to sufficiently maintain the degree of vacuum in the device, the area to which the getter material adheres must be increased. Therefore, the location of the getter and the material of the getter must be taken into consideration so that the getter material can sufficiently reach the inner surface of the apparatus where the getter material is required. It is difficult to do.

(3) Even after the getter processing is performed once,
The organic substance adhering to the inner surface of the apparatus evaporates in a vacuum with the passage of time, and when the partial pressure of the residual organic substance increases to a certain degree, the organic substance adheres again to the inner surface of the apparatus. At this time, if an organic substance adheres to the electron source, the element characteristics (current-voltage characteristics) of the surface-conduction type electron-emitting device change, and thus the getter process is repeatedly performed to reduce the partial pressure of the organic substance. This needs to be reduced, but it is difficult to do this with conventional gettering methods.

[0023]

The invention aims to provide an image forming apparatus that obtained to ensure necessary and sufficient getter capacity corresponding to a large area of the image forming apparatus.

[0025]

The structure of the present invention made to achieve the above object is as follows.

[0026]

[0027]

The present invention comprises a cold cathode type electron-emitting device.
An electron source having a driving element and emitted from the electron source
A phosphor that forms an image by irradiation with an electron beam.
In the image forming apparatus, there is no phosphor at the facing position
It consists of a surface conduction electron-emitting device,
An image forming apparatus characterized by comprising a getter element used as a getter.

The present invention further includes , as a feature thereof, a getter chamber communicating with a space in which the driving element is disposed, and the getter element is disposed in the getter chamber.

[0030] As a cold cathode electron-emitting device used as a drive element for definitive to the present invention, as previously described FE
, A MIM type, a surface conduction type electron-emitting device, and the like. In particular, a surface conduction type electron-emitting device having a simple structure and easy production is suitable. As a getter element,
A conduction electron-emitting device is used. In the present specification, the “drive element” means an element driven for the original purpose of an electron source as an electron source, and the “getter element” means a residual organic component in a vacuum or the like. Means an element used as a getter. In the present invention, the surface conduction type
How the getter element composed of the electron-emitting device functions as a getter will be described later in detail.

[0031] As described above, the present invention relates to a image forming apparatus using an electron source with a cold cathode type electron-emitting device will be described in detail the structure and operation of the present invention are described below.

First, the driving element according to the present invention is preferably used.
The basic configuration and manufacturing method of a surface conduction electron-emitting device suitable for use as a getter device will be described.

The basic configuration of a surface conduction electron-emitting device suitable for the present invention is a planar type in which a pair of device electrodes are formed on the same surface, and a pair of device electrodes vertically arranged via an insulating layer. There are two configurations of vertical type located.

First, a plane type surface conduction electron-emitting device will be described.

FIGS. 1A and 1B are views showing the basic structure of a flat surface conduction electron-emitting device. FIG. 1 (a)
1B is a plan view, FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG. 1A, 1 is a substrate, 2 is an electron emitting portion, 3 is a conductive thin film including the electron emitting portion 2, 4 and 5 Is an element electrode.

As the substrate 1, for example, quartz glass, Na
Glass, blue plate glass, blue plate glass, a laminate obtained by laminating SiO ₂ on a blue plate glass by a sputtering method or the like, and ceramics such as alumina.

The materials of the opposing device electrodes 4 and 5 are as follows.
A general conductor material is used, for example, Ni, Cr, Au,
Mo, W, Pt, Ti, Al, Cu, metal or an alloy such as Pd, and Pd, Ag, Au, printed conductors composed of RuO _2, metal or metal oxide such as Pd-Ag and glass, etc. , In ₂ O ₃ —SnO _2, etc., and a semiconductor conductor material such as polysilicon.

The element electrode interval L, the element electrode length W1, the shape of the conductive thin film 3, and the like are appropriately designed depending on the applied form and the like.

The element electrode interval L is usually several hundreds to several hundred μm.
m, which is set according to the voltage applied between the device electrodes and the electric field strength at which electrons can be emitted.
It is several tens μm.

The element electrode length W1 is preferably several μm to several hundred μm in consideration of the resistance value and the electron emission characteristics of the electrode, and the element electrode thickness d is several hundred μm to several μm.

The planar surface conduction electron-emitting device shown in FIG. 1 is formed by laminating element electrodes 4 and 5 and a conductive thin film 3 on a substrate 1 in this order. To
The conductive thin film 3 and the device electrodes 4 and 5 may be stacked in this order.

In order to obtain good electron emission characteristics, the conductive thin film 3 is particularly preferably a fine particle film composed of fine particles. It is set as appropriate according to the resistance value between the electrodes 4 and 5 and the forming conditions described later. The thickness of the conductive thin film 3 is preferably several Å to several thousand Å, particularly preferably 10 to 500 、, and its resistance value is 10 to 500 Å.
The sheet resistance is ³ to 10 ⁷ Ω / □.

The fine particle film is a film in which a plurality of fine particles are gathered, and has a fine structure not only in a state in which the fine particles are individually dispersed and arranged, but also in a state in which the fine particles are adjacent to each other or overlap each other (island shape). ). In the case of a fine particle film, the particle size of the fine particles is preferably from several to several thousand, particularly preferably from 10 to 200.

The main materials constituting the conductive thin film 3 are, for example, Pd, Pt, Ru, Ag, Au, Ti, In, Cu,
Metals such as Cr, Fe, Zn, Sn, Ta, W, and Pb;
dO, SnO ₂ , In ₂ O ₃ , PbO, Sb ₂ O ₃ , W
Oxides such as O _x , HfB ₂ , ZrB ₂ , LaB ₆ , Ce
Borides such as B ₆ , YB ₄ , GdB ₄ , TiC, ZrC,
Carbides such as HfC, TaC, SiC, WC, TiN, Z
It is made of nitride such as rN and HfN, semiconductor such as Si and Ge, and carbon.

The electron emitting portion 2 includes a crack, and the electron emission is performed from the vicinity of the crack. The electron-emitting portion 2 including the crack and the crack itself are formed depending on the thickness, the film quality, the material of the conductive thin film 3 and the manufacturing method such as forming conditions described later. Therefore, the position and shape of the electron-emitting portion 2 are not limited to the position and shape as shown in FIG.

The crack may have conductive fine particles having a particle size of several to several hundreds of mm. The conductive fine particles are similar to some or all of the elements of the material constituting the conductive thin film 3. Further, the electron emitting portion 2 including the crack and the conductive thin film 3 in the vicinity thereof may include carbon and a carbon compound.

Next, the basic structure of the vertical surface conduction electron-emitting device will be described.

FIG. 2 is a view showing a basic structure of a vertical surface conduction electron-emitting device. In FIG. 2, reference numeral 21 denotes a step forming member, and the same reference numerals as those in FIG. 1 denote the same members.

The substrate 1, the electron-emitting portion 2, the conductive thin film 3, and the device electrodes 4 and 5 are made of the same material as that of the above-mentioned flat surface-conduction type electron-emitting device.

The step forming member 21 is formed by, for example, a vacuum evaporation method.
It is made of an insulating material such as SiO ₂ provided by a printing method, a sputtering method or the like. The thickness of the step forming member 21 corresponds to the element electrode interval L (see FIG. 1) of the flat surface conduction electron-emitting device described above. The distance is set by the voltage applied between the electrodes 5 and the electric field strength capable of emitting electrons, but is preferably several hundreds to several tens μm, and particularly preferably several hundreds to
It is several μm.

Since the conductive thin film 3 is usually formed after the formation of the device electrodes 4 and 5, the conductive thin film 3 is laminated on the device electrodes 4 and 5. Further, as described in the description of the planar surface conduction electron-emitting device, the formation of the electron-emitting portion 2 depends on the manufacturing method such as the film thickness, film quality, material, and forming conditions of the conductive thin film 3 described later. , The position and shape are not limited to the position and shape as shown in FIG.

In the following description, of the above-mentioned plane type surface conduction electron-emitting device and vertical surface conduction type electron-emitting device, a plane type will be described as an example, but a vertical type may be used.

Next, an example of the manufacturing method of the surface conduction electron-emitting device having the structure shown in FIG. 1 will be described with reference to the manufacturing process diagram of FIG. When both the element for getter and the element for getter are composed of surface conduction electron-emitting devices, they can be manufactured simultaneously by exactly the same manufacturing method. The components having the same reference numerals as those in FIG. 1 are the same.

1) After sufficiently cleaning the insulating substrate 1 with a detergent, pure water and an organic solvent, depositing an element electrode material by a vacuum deposition method, a sputtering method, or the like, and then depositing the material on the surface of the substrate 1 by a photolithography technique. Next, device electrodes 4 and 5 are formed (FIG. 3A).

2) An organic metal solution is applied onto the insulating substrate 1 on which the device electrodes 4 and 5 are formed, and the solution is allowed to stand.
An organic metal thin film is formed. The organic metal solution is a solution of an organic compound containing a metal as a constituent element of the conductive thin film 3 as a main element. Thereafter, the organic metal thin film is heated and baked, and is patterned by lift-off, etching, or the like to form the conductive thin film 3 (FIG. 3B). In addition, here, the description has been made by the application method of the organic metal solution, but the invention is not limited thereto, and is formed by a vacuum evaporation method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like. In some cases.

3) Subsequently, an energization process called forming is performed. When power is supplied from a power source (not shown) between the device electrodes 4 and 5, an electron-emitting portion 2 having a changed structure is formed at the portion of the conductive thin film 3 (FIG. 3C). The conductive thin film 3 is locally destroyed, deformed or deteriorated by this energization process, and the portion where the structure is changed is the electron emitting portion 2.

FIG. 4 shows an example of a forming voltage waveform.

The voltage waveform is particularly preferably a pulse waveform.
There are a case where a voltage pulse having a pulse crest value as a constant voltage is continuously applied (FIG. 4A) and a case where a voltage pulse is applied while increasing the pulse crest value (FIG. 4B).

First, the case where the pulse peak value is a constant voltage will be described. T1 and T2 in FIG. 4A are the pulse width and pulse interval of the voltage waveform. For example, T1 is 1 μsec to 10 msec, T2 is 10 μsec to 100 msec,
The peak value of the triangular wave (peak voltage at the time of forming) is appropriately selected according to the form of the above-mentioned surface conduction electron-emitting device, and is set for several seconds to several tens of minutes under a vacuum surrounding with an appropriate degree of vacuum. Apply. Note that the voltage waveform to be applied is not limited to the illustrated triangular wave, and a desired waveform such as a rectangular wave can be used.

Next, a case where a voltage pulse is applied while increasing the pulse peak value will be described. T1 and T2 in FIG. 4B are the same as those in FIG. 4A, and the peak value of the triangular wave (peak voltage at the time of forming) is increased by, for example, about 0.1 V steps. The application is performed under an appropriate vacuum atmosphere as described in a).

Note that, during the pulse interval T2, the conductive thin film 3
(See FIGS. 1 and 2) The element current was measured at a voltage that does not locally destroy, deform, or alter the element, for example, a voltage of about 0.1 V, and the resistance was obtained. For example, a resistance of 1 M ohm or more was shown. Sometimes the forming ends.

4) Next, it is preferable to perform an activation step on the device after the forming step.

The activation step is, for example, 10 ^-4 to 10 ^-5 T
Similar to the description of the forming process, a process of repeating the application of a pulse with a constant pulse peak value at a degree of vacuum of about orr, and converts carbon and a carbon compound from an organic substance existing in a vacuum into an electron emitting portion. 2 (see FIG. 1), the device current and emission current (details will be described later)
This is a step that can significantly improve the state of. This activation step is preferably performed while measuring, for example, the device current and the emission current, and is completed when, for example, the emission current is saturated, since it is effective and is preferable. In addition, the pulse peak value in the activation step is preferably a peak value of a driving voltage applied when driving the element.

The above-mentioned carbon and carbon compound are graphite (indicating both single crystal and polycrystal) and amorphous carbon (indicating amorphous carbon and a mixture thereof with polycrystalline graphite). . Further, the deposited film thickness is preferably 500 ° or less, more preferably 300 ° or less.

5) More preferably, the surface conduction electron-emitting device thus manufactured is operated and driven in a vacuum atmosphere having a higher degree of vacuum than the forming step and the activating step. Further, more preferably, after the heating at 80 ° C. to 150 ° C. in the vacuum atmosphere with the higher degree of vacuum, the operation is driven.

The step 5) suppresses further deposition of carbon and carbon compounds, and stabilizes the device current and the emission current.

The surface conduction electron-emitting device according to the present invention can be manufactured by the above-described steps. However, the surface conduction electron-emitting device used as the getter device is different from the driving device, and is not necessarily the above 4). It is not necessary to go through the steps after the activation step.

The getter element according to the present invention functions to prevent a decrease in the degree of vacuum in a vacuum apparatus such as an electron source or an image forming apparatus and to prevent a decrease in the quality of the degree of vacuum. Functions as a getter by applying a voltage between the device electrodes 4 and 5 to deposit carbon and a carbon compound from an organic substance present in a vacuum on the device in the same manner as in the activation step. Is what you do.

Since the getter element according to the present invention does not use a getter material, even if getter processing is performed using the getter element, the getter material does not adhere to an electron source member or the like in a vacuum apparatus. Therefore, the degree of vacuum and the quality of vacuum can be maintained without affecting the electron emission characteristics of the driving element including the cold cathode type electron emission element.

Next, the basic characteristics of the surface conduction electron-emitting device suitably used as the driving device according to the present invention will be described below.

FIG. 5 is a schematic configuration diagram showing an example of a measurement evaluation system for measuring the electron emission characteristics of the surface conduction electron-emitting device having undergone the above-described manufacturing steps. First, this measurement evaluation system will be described.

In FIG. 5, the same reference numerals as those in FIG. 1 denote the same members. Reference numeral 51 denotes a power supply for applying a device voltage Vf to the device; 50, an ammeter for measuring a device current If flowing through the conductive thin film 3 between the device electrodes 4 and 5; An anode electrode for capturing the emission current Ie to be emitted; 53, a high-voltage power supply for applying a voltage to the anode electrode 54; 52, an ammeter for measuring the emission current Ie emitted from the electron emission section 2. , 55 are vacuum devices, and 56 is an exhaust pump.

The surface conduction electron-emitting device and the anode electrode 54 are installed in a vacuum device 55.
Is equipped with necessary equipment such as a vacuum gauge (not shown),
Measurement and evaluation of the surface conduction electron-emitting device can be performed under a desired vacuum.

The exhaust pump 56 is composed of a normal high vacuum system such as a turbo pump and a rotary pump, and an ultra high vacuum system such as an ion pump.
The entire vacuum device 55 and the substrate 1 of the surface conduction electron-emitting device can be heated to about 200 ° C. by a heater (not shown). In this measurement evaluation system, at the stage of assembling a display panel (see 201 in FIG. 8) described later, the display panel and its inside are configured as the vacuum device 55 and its inside, so that the above-described forming step and activation It can be applied to measurement evaluation and processing in the chemical conversion step.

The basic characteristics of the surface conduction electron-emitting device described below are as follows. The voltage of the anode electrode 54 of the above-mentioned measurement and evaluation system is 1 kV to 10 kV, and the distance H between the anode electrode 54 and the surface conduction electron-emitting device. Is usually set to 2 mm to 8 mm.

First, the emission current Ie and the device current If,
FIG. 6 (a solid line in the figure) shows a typical example of the relationship between the element voltages Vf.
Shown in In FIG. 6, the emission current Ie is the device current Ie.
Since it is significantly smaller than f, it is shown in arbitrary units.

As apparent from FIG. 6, the surface conduction electron-emitting device as the driving device according to the present invention has the following three characteristic characteristics with respect to the emission current Ie.

First, when an element voltage Vf of a surface conduction type electron-emitting device is applied with a device voltage Vf higher than a certain voltage (referred to as a threshold voltage: Vth in FIG. 6), the emission current Ie sharply increases. Below the threshold voltage Vth, the emission current Ie is hardly detected. That is, it is a nonlinear element having a clear threshold voltage Vth with respect to the emission current Ie.

Second, since the emission current Ie has a characteristic (referred to as MI characteristic) that monotonically increases with respect to the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf.

Thirdly, the amount of charge emitted by the anode electrode 54 (see FIG. 5) depends on the time during which the device voltage Vf is applied. That is, the amount of charge captured by the anode electrode 54 can be controlled by the time during which the device voltage Vf is applied.

The characteristic shown by the solid line in FIG.
Has the MI characteristic with respect to the element voltage Vf, and the element current If also has the MI characteristic with respect to the element voltage Vf. However, as shown by a broken line in FIG. On the other hand, a voltage control type negative resistance characteristic (referred to as VCNR characteristic) may be exhibited. Which property is shown
It depends on the manufacturing method of the element and the measurement conditions at the time of measurement. However,
Even if the device current If has a VCNR characteristic with respect to the device voltage Vf, the emission current Ie is M with respect to the device voltage Vf.
It has an I characteristic.

Because of the characteristic characteristics of the surface conduction electron-emitting device suitable as a driving device according to the present invention as described above, even in an electron source or an image forming apparatus in which a plurality of devices are arranged according to an input signal. Thus, the amount of emitted electrons can be easily controlled, and the invention can be applied to various fields.

Next, the arrangement of the driving element and the getter element in the electron source and the image forming apparatus of the present invention will be described.

The getter element comprising the surface conduction electron-emitting device according to the present invention can perform getter processing without affecting the electron emission characteristics of the drive element as described above. It is also possible to arrange them in the same space, and basically these arrangements are not particularly limited.

However, in an image forming apparatus provided with an image forming member such as a phosphor, when the driving element and the getter element are arranged close to each other in the same space, when these elements are operated simultaneously, the getter element Emitted electrons also contribute to image formation. For this reason, when the wiring and the driving circuit are configured so that the driving element and the getter element operate at the same time, for example, a getter chamber communicating with a space where the driving element is arranged is provided in a part of the image forming apparatus. Is provided, and a getter element is arranged in the getter chamber. The getter chamber may be a space provided on the side surface of the image forming apparatus, or a space on the side where the image forming apparatus has a dual structure of upper and lower sides and on which no image forming member is arranged.

When the driving element and the getter element do not operate at the same time, they can be arranged close to each other in the same space. One element may be arranged, or a getter element may be arranged around the driving element.

As described above, in the present invention, since a plurality of extremely small getter elements can be arranged relatively freely, a sufficient getter capability can be ensured, so that a sufficient degree of vacuum can be maintained even in a large-area image forming apparatus. Can be achieved.

Next, the arrangement of driving elements in the electron source of the present invention (an arrangement method directly related to the driving method) will be described.
A case where a surface conduction electron-emitting device suitable as a driving device is used as an example will be described together with its driving method.

The arrangement of the surface conduction electron-emitting devices as driving elements in the electron source of the present invention is not limited to the ladder arrangement as described in the section of the prior art, and also to the arrangement of m lines in the X direction. Are provided with n Y-directional wirings through an interlayer insulating layer, and X electrodes are respectively applied to a pair of device electrodes of the surface conduction electron-emitting device.
An arrangement method in which directional wiring and Y-directional wiring are connected is exemplified. This is hereinafter referred to as a simple matrix arrangement. First, the simple matrix arrangement will be described in detail.

According to the above-described basic characteristics of the surface conduction electron-emitting device, when the applied device voltage Vf exceeds the threshold voltage Vth, the electron is expressed by the peak value and pulse width of the applied pulsed voltage. The amount of release can be controlled. On the other hand, below the threshold voltage Vth, almost no electrons are emitted. Therefore, even when a large number of surface conduction electron-emitting devices are arranged as driving devices, a pulse voltage controlled according to an input signal is applied only by simple matrix wiring, and individual devices are selected and independently. It can be driven.

The simple matrix arrangement is based on the above principle, and the configuration of an electron source having a simple matrix arrangement as an example of the electron source of the present invention will be further described with reference to FIG.

In FIG. 8, the substrate 1 is a glass plate or the like as described above, and the number of the surface conduction electron-emitting devices 104 and the getter devices 601 as driving devices arranged on the substrate 1 is determined. The shape is appropriately set according to the application.

In FIG. 8, the getter element 601 is used as the Y-directional wiring 103 as a common wiring with the driving element 104.
Are also arranged in a simple matrix, but in the present invention, the arrangement of the getter elements (the arrangement method directly related to the driving method) and the driving method thereof are not particularly important,
There is no particular limitation. For example, the getter element 601 may be disposed on the periphery of the substrate 1 or on a surface opposite to the substrate surface on which the driving elements 104 are arranged by separate wiring.

The m X-directional wirings 102 for wiring the driving elements 104 have external terminals Dx1, Dx2,.
xm, and is a conductive metal or the like formed on the substrate 1 by a vacuum deposition method, a printing method, a sputtering method, or the like. Further, the material, the film thickness, and the wiring width are set so that the voltage is supplied to the many driving elements 104 almost uniformly.

The number m of X for wiring the getter element 601
The direction wiring 602 has external terminals Sx1, Sx2,.
It has Sxm, is made in the same manner as the X-direction wiring 102, and is formed alternately in parallel with the X-direction wiring one by one.

Driving element 104 and getter element 60
The n Y-directional wirings 103 for wiring 1 each have external terminals Dy1, Dy2,... Dyn, and are created in the same manner as the X-directional wiring 102.

[0097] Between the m X-directional wirings 102 and the m X-directional wirings 602 and the n Y-directional wirings 103,
An interlayer insulating layer (not shown) is installed and electrically separated,
It constitutes a matrix wiring. Note that both m and n are positive integers.

The interlayer insulating layer (not shown) is, for example, SiO ₂ formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The film thickness, material, and manufacturing method are appropriately set so as to be formed in a desired shape in the portion, and particularly to withstand the potential difference at the intersection of the X-directional wiring 102 and the X-directional wiring 602 and the Y-directional wiring 103.

Further, opposing element electrodes (not shown) of the driving element 104 and the getter element 601 are respectively m
The X-directional wirings 102 and 602 and the n Y-directional wirings 103 are electrically connected by a connection 105 made of a conductive metal or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. Things.

Here, the m X-direction wirings 102 and 60
2, the n Y-directional wirings 103, the connection 105, and the opposing device electrodes may have the same or some of the constituent elements that are the same or different from each other. Is appropriately selected from the materials and the like. The wires to these device electrodes may be collectively referred to as device electrodes when the material is the same as the device electrodes. Further, the driving element 104 and the getter element 601 may be formed on either the substrate 1 or an interlayer insulating layer (not shown).

As will be described later in detail, the X-direction wiring 102 is provided with a scanning signal (not shown) for applying a scanning signal in order to scan a row of the driving elements 104 arranged in the X direction in accordance with an input signal. The scanning signal applying means is electrically connected.

On the other hand, a modulation signal applying means (not shown) for applying a modulation signal in order to modulate each of the columns of the driving elements 104 arranged in the Y direction according to an input signal is provided on the Y direction wiring 103. Are electrically connected. Each driving element 1
The drive voltage applied to the drive element 04 is supplied as a difference voltage between the scan signal and the modulation signal applied to the drive element.

When operating the getter element 601, a signal is applied to the X-directional wiring 602 and the Y-directional wiring 103 so that a DC voltage or an AC voltage is applied to the getter element 601. The getter element 601
Is operated, the driving element 104 is not driven.

Next, an example of the image forming apparatus of the present invention using the electron source of the present invention having a simple matrix arrangement as shown in FIG. 7 will be described with reference to FIGS. FIG. 8 is a basic configuration diagram of the display panel 201, and FIG.
FIG. 10 is a block diagram showing an example of a driving circuit for performing television display on the display panel 201 of FIG. 8 in accordance with an NTSC television signal.

In FIG. 8, the same reference numerals as those in FIG.
The same members are shown, 1 is an electron source substrate on which the driving element 104 and the getter element 601 are arranged, 111 is a rear plate on which the substrate 1 is fixed, and 116 is a glass substrate 11
3, a face plate having a fluorescent film 114 as an image forming member and a metal back 115 formed on the inner surface of
112 is a support frame. Rear plate 111, support frame 1
12 and the face plate 116 are sealed by applying frit glass or the like to these joints and baking them in air or a nitrogen atmosphere at 400 ° C. to 500 ° C. for 10 minutes or more. 118.

The envelope 118 comprises the face plate 116, the support frame 112, and the rear plate 111, as described above. However, the rear plate 111 is provided mainly for the purpose of reinforcing the strength of the substrate 1, and if the substrate 1 itself has sufficient strength, the rear plate 1
11 is unnecessary, and the support frame 112 may be directly sealed to the substrate 1, and the envelope 118 may be constituted by the face plate 116, the support frame 112, and the substrate 1. Further, by further providing a support (not shown) called a spacer between the face plate 116 and the rear plate 111, the envelope 118 having sufficient strength against atmospheric pressure can be obtained.

The fluorescent film 114 is composed of only the phosphor 122 in the case of a monochrome, but is composed of the phosphor 1 in the case of a color.
Black stripes (FIG. 9A)
Alternatively, it is composed of a black conductive material 121 called a black matrix (FIG. 9B) and the like, and a phosphor 122.
The purpose of providing the black stripes and the black matrix is to provide the three primary color phosphors 12 necessary for color display.
The purpose is to make the color mixture or the like inconspicuous by making the painted portion between the two black, and to suppress a decrease in contrast due to reflection of external light on the fluorescent film 114. Black conductive material 12
As the first material, not only a material mainly containing graphite, which is generally used, but also other materials can be used as long as they are conductive and have little light transmission and reflection.

As a method of applying the phosphor 122 to the glass substrate 113, a precipitation method or a printing method is used regardless of monochrome or color.

Further, as shown in FIG.
A metal back 115 is usually provided on the inner surface side of 4.
The purpose of the metal back 115 is to reduce the light emitted from the phosphor 122 (see FIG.
Improving the brightness by specular reflection to the 6th side, acting as an electrode for applying an electron beam accelerating voltage from the high voltage terminal Hv, and damaging by the collision of negative ions generated in the envelope 118. Protection of the phosphor 122 from the laser beam. The metal back 115 can be manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 114 after the fluorescent film 114 is manufactured, and then depositing Al by vacuum evaporation or the like.

The face plate 116 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 114 in order to further enhance the conductivity of the fluorescent film 114.

When the above-mentioned sealing is performed, in the case of color, the phosphors 122 of each color must correspond to the driving element 104, so that it is necessary to perform sufficient alignment.

The inside of the envelope 118 is evacuated to a degree of vacuum of about 10 ⁻⁷ Torr through an exhaust pipe (not shown) and sealed.

When a surface conduction electron-emitting device is used as a driving element or a getter device according to the present invention, the above-described forming and subsequent manufacturing steps of the surface conduction electron-emitting device are usually performed in the same manner. This is performed immediately before or after the sealing of the envelope 118, and the content is appropriately set as described above.

The display panel 201 described above is, for example, shown in FIG.
Can be driven by a driving circuit as shown in FIG. However, the drive circuit of the getter element is omitted here for the sake of explanation of the image display drive.

In FIG. 10, reference numeral 201 denotes the display panel; 202, a scanning circuit; 203, a control circuit;
Is a shift register, 205 is a line memory, 206 is a synchronizing signal separation circuit, 207 is a modulation signal generator, Vx and V
a is a DC voltage source.

As shown in FIG. 10, the display panel 20
1 is connected to an external electric circuit via external terminals Dx1 to Dxm, external terminals Dy1 to Dyn, and a high voltage terminal Hv. Of these, the external terminals Dx1 to Dx1
xm is for sequentially driving the driving elements provided in the display panel 201, that is, the driving element groups arranged in a matrix of m rows and n columns, one row at a time (n elements). A scanning signal is applied.

On the other hand, the external terminals Dy1 to Dyn
A modulation signal for controlling an output electron beam of each driving element in one row selected by the scanning signal is applied.

The high voltage terminal Hv is connected to a DC voltage source Va.
Thus, for example, a DC voltage of 10 kV is supplied. This is an accelerating voltage for applying sufficient energy to the electron beam output from the driving element 104 to excite the phosphor.

The scanning circuit 202 has m switching elements therein (schematically indicated by S1 to Sm in FIG. 10).
Each of the switching elements S1 to Sm selects either the output voltage of the DC voltage source Vx or 0 V (ground level) and is electrically connected to the external terminals Dx1 to Dxm of the display panel 201. Things. Each of the switching elements S1 to Sm includes a control circuit 203
Operates on the basis of the control signal Tscan output by the device, and in fact, it can be easily configured by combining elements having a switching function such as an FET, for example.

The DC voltage source Vx in this example is connected to the surface-conduction electron-emitting device that is not scanned based on the characteristics (threshold voltage) of the surface-conduction electron-emitting device that is the driving element 104. It is set so as to output a constant voltage such that the applied driving voltage is equal to or lower than the threshold voltage.

The control circuit 203 has a function of coordinating the operation of each unit so that an appropriate display is performed based on an externally input image signal. A synchronization signal Tsyn sent from a synchronization signal separation circuit 206 described below.
Based on c, each control signal of Tscan, Tsft, and Tmry is generated for each unit.

The synchronizing signal separating circuit 206 is a circuit for separating a synchronizing signal component and a luminance signal component from an externally input NTSC television signal. ) With the circuit,
It can be easily configured. Sync signal separation circuit 206
The sync signal separated by is composed of a vertical sync signal and a horizontal sync signal, as is well known. Here, it is illustrated as Tsync for convenience of explanation. On the other hand, the luminance signal component of the image separated from the television signal is referred to as D for convenience.
This is illustrated as an ATA signal. This DATA signal is input to the shift register 204.

The shift register 204 is for serially / parallel-converting the DATA signal input serially in time series for each line of an image, and based on a control signal Tsft sent from the control circuit 203. Operate. This control signal Tsft is supplied to the shift register 20
4 may be rephrased as the shift clock. Also,
The data of one line of the serial / parallel-converted image (corresponding to the driving data of n driving elements) is
The shift register 204 outputs as n parallel signals Id1 to Idn.

The line memory 205 is a storage device for storing data for one line of an image for a required time, and stores the contents of Id1 to Idn as appropriate according to a control signal Tmry sent from the control circuit 203. The stored contents are output as I'd1 to I'dn and input to the modulation signal generator 207.

The modulation signal generator 207 is a signal line for appropriately driving and modulating each of the driving elements in accordance with each of the image data I'd1 to I'dn. Display panel 2 through Dy1 to Dyn
01.

As described above, the surface conduction electron-emitting device has a distinct threshold voltage for electron emission, and electron emission occurs only when a voltage exceeding the threshold voltage is applied. For voltages exceeding the threshold voltage,
The emission current also changes according to the change in the voltage applied to the surface conduction electron-emitting device. By changing the material, configuration, and manufacturing method of the surface conduction electron-emitting device, the value of the threshold voltage and the degree of change of the emission current with respect to the applied voltage may be changed. I can say the thing.

That is, when a pulsed voltage is applied to the surface conduction electron-emitting device, for example, even if a voltage lower than the threshold voltage is applied, electron emission does not occur, but a voltage exceeding the threshold voltage is applied. In this case, electron emission occurs. At that time, first, it is possible to control the intensity of the output electron beam by changing the peak value of the voltage pulse. Second, by changing the width of the voltage pulse, it is possible to control the total amount of charges of the output electron beam.

Accordingly, as a method of modulating a surface conduction electron-emitting device as a driving device in accordance with an input signal, there are a voltage modulation method and a pulse width modulation method.
In the case of performing the voltage modulation method, the modulation signal generator 207 generates a voltage pulse of a fixed length, but uses a voltage modulation circuit capable of appropriately modulating the peak value of the pulse according to input data. In the case of performing the pulse width modulation method, the modulation signal generator 207 generates a voltage pulse having a constant peak value, but a pulse width modulation method circuit capable of appropriately modulating the pulse width according to input data. Used.

The shift register 204 and the line memory 20
Reference numeral 5 may be a digital signal type or an analog signal type, as long as it can perform serial / parallel conversion and storage of an image signal at a predetermined speed.

When using the digital signal system, it is necessary to convert the output signal DATA of the synchronizing signal separation circuit 206 into a digital signal. This can be achieved by providing an A / D converter at the output of the synchronization signal separation circuit 206.

In connection with this, the line memory 20
Depending on whether the output signal of 5 is a digital signal or an analog signal,
The circuit provided in modulation signal generator 207 is slightly different.

That is, in the case of a voltage modulation system using a digital signal, a well-known D / A conversion circuit may be used as the modulation signal generator 207, and an amplification circuit or the like may be added as necessary. In the case of a pulse width modulation method using a digital signal, the modulation signal generator 207 includes, for example, a high-speed oscillator, a counter (counter) for counting the number of waves output from the oscillator, and an output value of the counter and an output value of the memory. It can be easily configured by using a circuit in which comparators for comparison are combined. Further, if necessary, an amplifier may be added for amplifying the voltage of the pulse-width-modulated signal output from the comparator to the drive voltage of the surface-conduction electron-emitting device.

On the other hand, in the case of the voltage modulation method using an analog signal, for example, a well-known amplifier circuit using an operational amplifier or the like may be used as the modulation signal generator 207, and a level shift circuit or the like may be added as necessary. You may. In the case of a pulse width modulation method using an analog signal, for example, a well-known voltage-controlled oscillation circuit (VCO) may be used, and a voltage is amplified to a drive voltage of a surface conduction electron-emitting device as necessary. May be added.

The image forming apparatus of the present invention having the display panel 201 and the driving circuit as described above has the external terminals Dx1 to Dx1.
By applying a voltage from Dxm and Dy1 to Dyn, electrons can be emitted from the surface conduction electron-emitting device, which is an arbitrary driving device 104, and the metal back 115 or the transparent electrode (non-conductive) can be emitted through the high voltage terminal Hv. (Shown), a high voltage is applied to accelerate the electron beam, and the excited electron beam collides with the fluorescent film 114 to generate and emit light, thereby performing television display according to an NTSC television signal. Can be done.

The configuration described above is a schematic configuration necessary for obtaining the image forming apparatus of the present invention used for display and the like. For example, detailed portions such as materials of each member are limited to those described above. Instead, it is appropriately selected so as to be suitable for the use of the image forming apparatus. Although the NTSC system has been described as an example of the input signal, the image forming apparatus of the present invention is not limited to this, and may employ another system such as a PAL or SECAM system. For example, a high-definition TV system such as a MUSE system may be used.

Next, an example of the above-described trapezoidal electron source and an image forming apparatus of the present invention using the same will be described with reference to FIGS. 11 and 12. FIG.

In FIG. 11, reference numeral 1 denotes a substrate, 104 denotes a driving element, 601 denotes a getter element, and 304 denotes a common wiring for connecting each row of the driving element 104 and the getter element 601. External terminals D1 to D1
It has 0.

Driving element 104 and getter element 60
1 are arranged in parallel on the substrate 1. This is called an element row. These element rows are arranged in a plurality of rows to constitute an electron source.

By applying an appropriate drive voltage between the common wiring 304 of each element row (for example, the common wiring 304 of the external terminals D1 and D2), each element row can be driven independently. That is, a voltage exceeding the threshold voltage is applied to the element row of the driving element that wants to emit the electron beam, and a voltage lower than the threshold voltage is applied to the element row of the driving element that does not want to emit the electron beam. What is necessary is just to apply. Also,
The same applies when the getter element is operated.

FIG. 12 is a view showing the structure of a display panel 301 provided with the above-mentioned trapezoidal arrangement of electron sources.

In FIG. 12, reference numeral 302 denotes a grid electrode,
Reference numeral 303 denotes an opening through which electrons pass, D1 to Dm denote external terminals for applying a voltage to each element row, and G1 to Gn denote terminals connected to the grid electrode 302.

In FIG. 12, the same reference numerals as those in FIG. 8 denote the same members, and the main difference between the display panel 201 using the electron sources in the simple matrix arrangement shown in FIG. The point is that a grid electrode 302 is provided between the electrodes 116.

The grid electrode 302 is provided between the substrate 1 and the face plate 116 as described above. The grid electrode 302 can modulate the electron beam emitted from the driving element 104.
In order to allow an electron beam to pass through, a circular opening 303 corresponding to each driving element 104 is provided in a striped electrode provided orthogonal to the ladder-shaped element row. I have.

The shape and arrangement position of the grid electrode 302
The opening 303 is not necessarily shown in FIG. 12, and a large number of openings 303 may be provided in a mesh shape. The grid electrode 302 may be provided around or near the driving element 104, for example.

The external terminals D1 to Dm and G1 to Gn are connected to a drive circuit (not shown). A modulation signal for one line of an image is applied to the column of the grid electrode 302 in synchronization with the sequential driving (scanning) of the element rows one by one, so that each electron beam is applied to the fluorescent film 114. The irradiation can be controlled and the image can be displayed line by line.

As described above, the image forming apparatus of the present invention
It can be obtained by using any of the electron sources of the present invention in a simple matrix arrangement or a trapezoidal arrangement, and is suitable not only for the above-described television broadcast display device, but also as a video conference system and a display device such as a computer. A device is obtained. Further, it can be used as an exposure device of an optical printer including a photosensitive drum and the like.

[0147]

The present invention will be further described with reference to the following examples.

[Embodiment 1] In this embodiment, a surface conduction electron-emitting device as shown in FIG. 1 is used as a driving element and a getter element, and an electron source having a simple matrix arrangement as shown in FIG. Next, an example in which an image forming apparatus as shown in FIG. 8 is manufactured using this electron source will be described.

FIG. 13 is a plan view of a part of the electron source. FIG. 14 is a sectional view taken along the line AA ′ in the figure. However, the same reference numerals in FIGS. 7, 8, 13 and 14 denote the same members.

Here, 1 is a substrate, 104 is a driving element,
Reference numeral 601 denotes a getter element, 102 denotes an X-direction wiring connected to the drive element 104, and 602 denotes a getter element 601.
, 103 is a Y-direction wiring connected to the driving element 104 and the getter element 601, 3 is a conductive thin film, 4 and 5 are device electrodes, 401 is an interlayer insulating layer, and 402 is a device. It is a contact hole for electrical connection between the electrode 4 and the X-direction wirings 102, 601.

First, a method of manufacturing an electron source according to this embodiment will be specifically described with reference to FIGS. Note that the following steps a to h correspond to (a) to (h) of FIG.

Step a: On a substrate 1 in which a 0.5 μm-thick silicon oxide film was formed on a cleaned blue plate glass by a sputtering method, a Cr film having a thickness of 50 ° and a thickness of 6 mm were formed by vacuum evaporation.
000 of Au is sequentially laminated, and then the photoresist (AZ
1370 Hoechst Co., Ltd.), spin-coated and baked with a spinner, exposed and developed a photomask image,
A resist pattern for the directional wirings 102 and 601 was formed, and the Au / Cr deposited film was wet-etched to form X-directional wirings 102 and 601 having desired shapes.

Step b: Next, an interlayer insulating layer 401 made of a silicon oxide film having a thickness of 1.0 μm was deposited by RF sputtering.

Step c: A photoresist pattern for forming a contact hole 402 is formed on the silicon oxide film deposited in the step b, and the photoresist pattern is used as a mask to form an interlayer insulating layer 40.
1 was etched to form a contact hole 402. Etching using CF ₄ and H ₂ gas RIE (R
active Ion Etching) method.

Step d: Thereafter, a pattern to be a gap L between the device electrodes 4 and 5 and the device electrode is formed by a photoresist (R
D-2000N-41, manufactured by Hitachi Chemical Co., Ltd.), and a vacuum evaporation method is used to form a 50-mm thick Ti and a 1000-mm thick N.
i were sequentially deposited. The photoresist pattern was dissolved with an organic solvent, and the Ni / Ti deposited film was lifted off to form device electrodes 4 and 5 having a device electrode interval L of 3 μm and a width W1 of 300 μm.

Step e: Upper wiring 10 on device electrodes 4 and 5
After a photoresist pattern of No. 3 is formed, Ti of 50 .mu.m thick and Au of 5000 .mu.m are sequentially deposited by vacuum evaporation, and unnecessary portions are removed by lift-off to form a Y-directional wiring 103 having a desired shape. did.

Step f: A 1000 .ANG.-thick C is formed by using a mask having an opening L near the device electrode gap L and its vicinity.
An r film 403 is deposited and patterned by vacuum evaporation, and an organic Pd (ccp-4230 Okuno Pharmaceutical Co., Ltd.) is formed thereon.
) Is applied at 300 ° C, 12 ° C in air.
For 2 minutes. The thus formed conductive thin film 3 mainly composed of PdO fine particles had a thickness of 100 ° and a sheet resistance of 5 × 10 ⁴ Ω / □.

Step g: Cr film 403 by lift-off method
To remove the conductive thin film 3 having a desired pattern shape.
Was formed.

Step h: A resist was applied to the entire surface, developed using a mask after exposure, and the resist was removed only in the contact hole 402. Thereafter, by vacuum evaporation, Ti with a thickness of 50 ° and Au with a thickness of 5000 ° are sequentially deposited.
Unnecessary portions were removed by lift-off to bury the contact holes 402.

Through the above steps, the X-directional wirings 102 and 603, the interlayer insulating layer 401, the Y-directional wiring 103, the driving element 104, the getter element 601 and the like are formed on the insulating substrate 1, and the unformed electron source is formed. I got

An image forming apparatus was manufactured by using the unformed electron source manufactured as described above. The manufacturing procedure will be described below with reference to FIGS.

First, after fixing the substrate 1 of the unformed electron source to the rear plate 111, the substrate 1
Above, a face plate 116 (formed by forming a fluorescent film 114 serving as an image forming member and a metal back 115 on the inner surface of a glass substrate 113) is provided.
12, face plate 116, support frame 1
12. A frit glass was applied to the joint of the rear plate 111 and sealed by baking at 400 ° C. for 10 minutes in the air. The fixing of the substrate 1 to the rear plate 111 was also performed using frit glass.

The fluorescent film 114 serving as an image forming member
Is a stripe shape (FIG. 9) to realize color.
(Refer to (a)), a black stripe is formed first, and each color phosphor 12
2 was applied to form a fluorescent film 114. As a material for the black stripe, a material mainly containing graphite, which is generally used, was used.

Further, a metal back 115 was provided on the inner surface side of the fluorescent film 114. The metal back 115 is the fluorescent film 1
After the fabrication of 14, a smoothing process (usually called filming) of the inner surface of the fluorescent film 114 is performed, and then A
1 was produced by vacuum evaporation.

In the face plate 116, a transparent electrode may be provided on the outer surface side of the fluorescent film 114 in order to further increase the conductivity of the fluorescent film 114, but in this embodiment, only the metal back 115 is provided. Omitted because sufficient conductivity was obtained.

At the time of performing the above-mentioned sealing, in the case of color, since the phosphors 122 of each color must correspond to the driving elements 104, sufficient alignment was performed.

The atmosphere in the envelope 118 completed as described above is exhausted by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the outer terminals Dx1 to Dxm and Dy1 to Dx1 to Dx1 to Dxm. Drive element 104 through Dyn
A voltage was applied between the device electrodes 4 and 5, and the above-described forming process was performed to form the electron-emitting portion 2.

Similarly, a voltage is applied between the device electrodes 4 and 5 of the getter device 601 through the external terminals Sx1 to Sxm and Dy1 to Dyn, and the above-described forming process is performed to form the electron emission portion 2. did.

In the present embodiment, FIG.
Using the voltage waveform shown in (a), T1 is 1 ms, T2 is 10 ms, the peak value of the triangular wave (peak voltage at the time of forming) is 5 V, and the vacuum degree is about 1 × 10 ⁻⁶ Torr for 60 seconds. went. The electron-emitting portion 2 thus formed contained cracks, in which fine particles mainly composed of palladium were dispersed and arranged, and the average particle size of the fine particles was 30 °.

Thereafter, the envelope 1 is passed through an exhaust pipe (not shown).
The inside of the vessel 18 was evacuated to a degree of vacuum of about 10 ^−6.5 Torr, and the exhaust pipe was heated and welded with a gas burner to seal the envelope 118. Finally, gettering was performed by a high-frequency heating method in order to maintain the degree of vacuum after sealing. The getter contained Ba as a main component.

The display panel 20 completed as described above
In FIG. 1 (see FIG. 8), before applying voltage to the driving element 104 to emit electrons, the external terminals Sx1 to Sx1
xm and Dy1 to Dyn, the getter element 60
A voltage was applied to No. 1 to emit electrons. With this process,
The carbon and the carbon compound remaining in the vacuum container (the envelope 118) were adsorbed to the electron-emitting portion 2 and the like of the getter element 601.

Next, the external terminals Dx1 to Dxm and D
A scanning signal and a modulation signal are applied to the driving element 104 by signal generation means (not shown) through y1 to Dyn to emit electrons, and a high voltage of several kV or more is applied to the metal back 115 through the high voltage terminal Hv. The image was displayed by accelerating the electron beam, colliding with the fluorescent film 114, exciting and emitting light. As a result, a high-quality display image that was stable over a long period of time was obtained.

In this embodiment, the getter element 601 is used.
The getter process performed by driving the device may be appropriately performed according to the use progress of the image display device, and the degree of vacuum and the quality in the vacuum container can be maintained for a long time.

[Embodiment 2] An electron source having a trapezoidal arrangement as shown in FIG. 11 was manufactured by using a driving element comprising a surface conduction electron-emitting device and a getter element similar to those in Embodiment 1. Using this, an image forming apparatus as shown in FIG. 12 was manufactured. The method for manufacturing the display panel 301 is described in Example 1.
The description is omitted because it is the same as.

In the image forming apparatus of this embodiment, before the voltage is applied to the driving element 104 to display an image, the common wiring 304 of each element row of the getter element 601, that is, the adjacent external terminal D 2 is connected to the common terminal 304. D3, D4 and D5, D6 and D
7, a voltage was applied to the common wiring 304 of D8 and D9, and electrons were emitted from the getter element 601 to perform getter processing.

Next, the common wiring 304 of each element row of the driving element 104, that is, adjacent external terminals D1, D2, D3
And D4, D5 and D6, D7 and D8, and D9 and D10. A voltage is applied to the common wiring 304, electrons are emitted from the driving element 104, and the emitted electrons are modulated by an image signal applied to the grid electrode 302. Displayed. As a result, similarly to Example 1, a high-quality display image that was stable over a long period of time was obtained.

Also in the image display device of this embodiment, the getter treatment may be appropriately performed as the device is used, and the degree of vacuum and the quality in the vacuum vessel can be maintained for a long period of time.

[Embodiment 3] An example in which a planar cold cathode electron-emitting device is used as a driving device and a surface conduction electron-emitting device is used as a getter device will be described.

FIG. 16 shows the manufacturing process of the planar cold cathode electron-emitting device of this embodiment. Hereinafter, the manufacturing method will be described.

1) A 1.5 μm thick SiO ₂ film 70 as an insulating layer on the surface of a Si wafer substrate 700 by thermal oxidation.
After forming a 1, a thickness of 0.2 on the surface of the SiO ₂ film 701
A μm W ₂ C film 702 was formed. This W ₂ C film 702
The cold cathode 704 having the convex portion 703 and the gate electrode 705 were simultaneously formed by photoetching. The interval between the cold cathode convex portion 703 and the gate electrode 705 is 1 μm, and the radius of curvature of the tip of the cold cathode convex portion 703 is about 1 μm (FIG. 16A).

2) Next, this substrate 700 is immersed in a buffer etch solution (HF: NH ₄ F = 1: 6) to form SiO ₂
The film 701 is isotropically etched to form a concave portion 706 at the lower part of the cold cathode tip, thereby making the tip of the cold cathode eave-shaped, and at the same time, a convex part 703 having a tip radius of curvature of 0.1 μm or less under the cold cathode. Was formed (FIG. 16B).

3) Next, this substrate 700 was immersed in hydrofluoric acid and wasotropically etched from above and below until the eaves 708 of the cold cathode were completely removed. The etching from below is performed on the convex portion 7 having a tip curvature radius of 0.1 μm or less.
Since the elongation occurs along the insulating layer 701 below the cold cathode having No. 03, if the eaves portion is removed, a cold cathode 704 having a convex tip 709 having a tip curvature radius of 0.1 μm or less is formed. The film thickness of the cold cathode 704 and the gate electrode 705 is about 0.1 μm (FIG. 16C).

On the Si wafer substrate 700 on which the driving element composed of the planar cold cathode electron-emitting element was manufactured as described above, the peripheral portion of the driving element was replaced with the same surface conduction type electron-emitting element as in the first embodiment. A getter element was prepared and arranged to obtain an electron source.

Further, using this electron source, a display panel similar to that of Example 1 was formed to obtain an image forming apparatus.

In the image forming apparatus of this embodiment, before applying a voltage to the driving element to display an image, electrons were emitted from the getter element to perform getter processing.

Next, electrons were emitted from the driving element to display an image. As a result, similarly to Example 1, a high-quality display image that was stable over a long period of time was obtained.

Also in the image display device of this embodiment, the getter treatment may be appropriately performed as the device is used, and the degree of vacuum in the vacuum vessel and its quality can be maintained for a long period of time.

[Embodiment 4] A drive element and a getter element composed of the same surface conduction electron-emitting device as in Example 1 were used, and a getter element was arranged around a drive element for forming an image. An image forming apparatus as shown in FIG. 17 was manufactured using the electron source. In FIG. 17, the same members as those in FIG. 8 indicate the same members.

In the electron source of this embodiment, the driving element 104
Were arranged and wired in a matrix in the same manner as in Example 1, and the getter element 601 was arranged around it. However, the fluorescent film 114 and the metal back 115 are not provided on the glass substrate 113 facing the getter element 601.

The method of manufacturing the display panel 201 is the same as that of the first embodiment, and a description thereof will be omitted.

In the image forming apparatus of this embodiment, before a voltage is applied to the driving element 104 to display an image, electrons are emitted from the getter element 601 to perform getter processing.

Next, driving of the getter element 601 was stopped, electrons were emitted from the driving element 104, and an image was displayed. As a result, similarly to Example 1, a high-quality display image that was stable over a long period of time was obtained.

Also in the image display device of this embodiment, the getter treatment may be appropriately performed as the device is used, and the degree of vacuum and the quality of the vacuum container can be maintained for a long period of time.

Also in the structure of this embodiment, since the getter element 601 is extremely small, the space other than the driving element 104 for forming an image does not become extremely large, and the entire image forming apparatus is compact. Can be summarized.

Example 5 An image forming apparatus as shown in FIG. 18 was manufactured by using a driving element and a getter element composed of the same surface conduction electron-emitting device as in Example 1.
In FIG. 18, the same components as those in FIG. 8 indicate the same members.

In the electron source of this embodiment, the driving element 104
Were arranged and wired in a matrix in the same manner as in Example 1, and the getter element 601 was arranged around it. Display panel 2
01 is provided with a getter chamber 800 which is separated from a space for image formation in which the driving elements 104 are disposed by a partition frame 801, and the getter elements 601 are disposed in the getter chamber 800. I have. Partition frame 801
Has an opening 802 of an appropriate size, and a space for image formation in which the driving element 104 is arranged communicates with the getter chamber 800. The fluorescent film 114 and the metal back 115 are not provided on the glass substrate 113 facing the getter element 601.

In the image forming apparatus of this embodiment, before a voltage is applied to the driving element 104 to display an image, electrons are emitted from the getter element 601 to perform a getter process.

Next, driving of the getter element 601 was stopped, electrons were emitted from the driving element 104, and an image was displayed. As a result, similarly to Example 1, a high-quality display image that was stable over a long period of time was obtained.

Also in the image display device of this embodiment, the getter process may be appropriately performed as the device is used, and the degree of vacuum in the vacuum vessel and the quality thereof can be maintained for a long time.

In the case of the structure as in this embodiment, ions and the like from the phosphor screen hardly adhere to the getter element 601,
The getter function can be maintained for a longer time.

Further, since the getter chamber 800 is provided separately, the number of the getter elements 601 can be set freely without much restriction from the space for image formation. Therefore, even when a large screen device is formed, necessary and sufficient getter ability can be provided.

Furthermore, since the getter chamber 800 has no electrode for extracting electrons for forming an image and is spatially separated, the getter chamber 800 can be operated simultaneously with the driving element 104.

Example 6 An image forming apparatus as shown in FIG. 19 was manufactured by using a driving element comprising a surface conduction electron-emitting device and a getter element as in Example 1.
In FIG. 19, the same components as those in FIG. 8 indicate the same members.

The electron source of this embodiment has a two-layer structure, and the driving element 104 is provided on the upper layer (on the intermediate plate 900).
Are arranged and wired in a matrix in the same manner as in the first embodiment, and the getter element 6 is provided in a lower layer (on the rear plate 111).
01 was arranged. A space for image formation between the intermediate plate 900 and the face plate 116;
The space between the rear plate 111 and the intermediate plate 900
At the side. In addition, these spaces can be communicated by providing an opening at an appropriate position of the intermediate plate 900, for example.

In the image forming apparatus of this embodiment, before a voltage is applied to the driving element 104 to display an image, electrons are emitted from the getter element 601 to perform a getter process.

Next, driving of the getter element 601 was stopped, electrons were emitted from the driving element 104, and an image was displayed. As a result, similarly to Example 1, a high-quality display image that was stable over a long period of time was obtained.

Also in the image display device of this embodiment, the getter treatment may be appropriately performed as the device is used, and the degree of vacuum and the quality of the vacuum in the vacuum vessel can be maintained for a long period of time.

In the case of the structure as in this embodiment, the fifth embodiment
Similarly to the case described above, ions and the like from the phosphor screen hardly adhere to the getter element 601, and the getter function can be maintained for a longer time.

Further, since the space between the intermediate plate 900 and the rear plate 111 is the getter chamber 800, there is little restriction from the space for image formation.
The number of getter elements 601 can be set freely. Therefore, even when a large screen device is formed, necessary and sufficient getter ability can be provided.

Further, since the getter chamber 800 has no electrode for extracting electrons for forming an image and is spatially separated, it can be operated simultaneously with the driving element 104.

[Embodiment 7] FIG. 20 shows the display panel (display panel) 201 (see FIG. 8) of the embodiment 1 with image information provided from various image information sources such as television broadcasting. FIG. 1 is a diagram illustrating an example of an image display device of the present invention configured to be able to display.

In the figure, reference numeral 201 denotes a display panel;
1 is a display panel driving circuit, 1002 is a display controller, 1003 is a multiplexer, 10
04 is a decoder, 1005 is an input / output interface circuit, 1006 is a CPU, 1007 is an image generation circuit, 10
08, 1009 and 1010 are image memory interface circuits, 1011 is an image input interface circuit,
1012 and 1013 are TV signal receiving circuits, and 1014 is an input unit.

When the present display device receives a signal including both video information and audio information, such as a television signal, it naturally reproduces the audio simultaneously with the display of the video. Descriptions of circuits, speakers, and the like related to reception, separation, reproduction, processing, storage, and the like of audio information that are not directly related to the features of the present invention are omitted.

Hereinafter, each part will be described along the flow of the image signal.

First, the TV signal receiving circuit 1013 is a circuit for receiving a TV image signal transmitted using a wireless transmission system such as radio waves or spatial optical communication.

The format of the TV signal to be received is not particularly limited. For example, NTSC, PAL, SE
Various systems such as the CAM system may be used. Further, a TV signal composed of a larger number of scanning lines than these, for example, a so-called high-definition TV including the MUSE system is suitable for taking advantage of the display panel 201 suitable for a large area and a large number of pixels. Signal source.

The T signal received by the TV signal receiving circuit 1013
The V signal is output to the decoder 1004.

The image TV signal receiving circuit 1012 is a circuit for receiving a TV image signal transmitted using a wired transmission system such as a coaxial cable or an optical fiber. Similarly to the TV signal receiving circuit 1013, the system of the TV signal to be received is not particularly limited, and the TV signal received by this circuit is also output to the decoder 1004.

Image input interface circuit 1011
Is a circuit for capturing an image signal supplied from an image input device such as a TV camera or an image reading scanner. The captured image signal is output to the decoder 1004.

Image memory interface circuit 1010
Is a circuit for capturing an image signal stored in a video tape recorder (hereinafter abbreviated as VTR). The captured image signal is output to a decoder 1004.

Image memory interface circuit 1009
Is a circuit for taking in an image signal stored in a video disk.
04 is output.

Image memory-interface circuit 100
Reference numeral 8 denotes a circuit for capturing an image signal from a device storing still image data, such as a so-called still image disk.
Is output to

The input / output interface circuit 1005 comprises:
This is a circuit for connecting the present display device to an output device such as an external computer, computer network, or printer. In addition to inputting and outputting image data and character / graphic information, control signals and numerical data can be input and output between the CPU 1006 of the display device and the outside in some cases.

The image generation circuit 1007 is provided with image data, character / graphic information input from the outside via the input / output interface circuit 1005, or the CPU 1006.
This is a circuit for generating display image data based on the image data and character / graphic information output from the display unit. Inside this circuit, for example, a rewritable memory for storing image data and character / graphic information, a read-only memory storing an image pattern corresponding to a character code,
A circuit necessary for generating an image such as a processor for performing image processing is incorporated therein.

The display image data generated by the present circuit is output to the decoder 1004, but may be output to an external computer network or printer via the input / output interface circuit 1005 in some cases.

The CPU 1006 mainly performs operations related to operation control of the display device and generation, selection, and editing of a display image.

For example, a control signal is output to the multiplexer 1003, and image signals to be displayed on the display panel 201 are appropriately selected or combined. At that time, a control signal is generated for the display panel controller 1002 in accordance with an image signal to be displayed, and a display frequency, a scanning method (for example, interlaced or non-interlaced), and the number of scanning lines per screen are displayed. The operation of the device is appropriately controlled. Further, image data and character / graphic information are directly output to the image generation circuit 1007,
Alternatively, an external computer or memory is accessed via the input / output interface circuit 1005 to input image data and character / graphic information.

It should be noted that the CPU 1006 may, of course, be involved in work for other purposes. For example, it may be directly related to a function of generating and processing information, such as a personal computer or a word processor. Alternatively, as described above, the computer may be connected to an external computer network via the input / output interface circuit 1005 to perform operations such as numerical calculations in cooperation with external devices.

The input unit 1014 is for the user to input commands, programs, data, etc. to the CPU 1006. For example, in addition to a keyboard and a mouse,
Various input devices such as a joystick, a barcode reader, and a voice recognition device can be used.

The decoder 1004 converts various image signals input from the above 1007 to 1013 into three primary color signals,
Alternatively, it is a circuit for inversely converting a luminance signal into an I signal and a Q signal. As shown by the dotted line in FIG.
004 preferably has an internal image memory. This is for handling television signals that require an image memory when performing inverse conversion, such as the MUSE method.

The provision of the image memory facilitates the display of a still image. Alternatively, in cooperation with the image generation circuit 1007 and the CPU 1006, there is obtained an advantage that image processing and editing including image thinning, interpolation, enlargement, reduction, and synthesis become easy.

A multiplexer 1003 is connected to the CPU 10
A display image is appropriately selected based on a control signal input from the controller 06. That is, the multiplexer 1003 selects a desired image signal from the inversely converted image signals input from the decoder 1004 and outputs the selected image signal to the drive circuit 1001. In that case, by switching and selecting an image signal within one screen display time, it is also possible to divide one screen into a plurality of areas and display different images depending on the areas, as in a so-called multi-screen TV. .

Display panel controller 1002
Is a circuit for controlling the operation of the drive circuit 1001 based on a control signal input from the CPU 1006.

[0234] As the elements related to the basic operation of the display panel 201, for example, the display panel 201
A signal for controlling the operation sequence of the driving power supply (not shown) is output to the driving circuit 1001. As a method related to the driving method of the display panel 201, a signal for controlling, for example, a screen display frequency and a scanning method (for example, interlaced or non-interlaced) is output to the driving circuit 1001. In some cases, a control signal relating to image quality adjustment such as luminance, contrast, color tone, and sharpness of a display image is supplied to the driving circuit 10.
01 may be output.

The drive circuit 1001 is a circuit for generating a drive signal to be applied to the display panel 201, based on an image signal input from the multiplexer 1003 and a control signal input from the display panel controller 1002. It works.

The function of each section has been described above. With the configuration illustrated in FIG. 20, in this display device, image information input from various image information sources is displayed on the display panel 2.
01 can be displayed. That is, various image signals including television broadcasting are supplied to the decoder 1004.
After being inversely converted in, the signal is appropriately selected in the multiplexer 1003 and input to the drive circuit 1001. On the other hand, the display controller 1002 generates a control signal for controlling the operation of the driving circuit 1001 according to the image signal to be displayed. The drive circuit 1001 applies a drive signal to the display panel 201 based on the image signal and the control signal. Thus, an image is displayed on the display panel 201. These series of operations are totally controlled by the CPU 1006.

In the present image forming apparatus, the image memory built in the decoder 1004 and the image generation circuit 100
7 and the CPU 1006 involve not only displaying a selected one of a plurality of pieces of image information but also enlarging, reducing, rotating, moving, edge emphasizing, thinning out, and interpolating the image information to be displayed. It is also possible to perform image processing such as color conversion, image aspect ratio conversion and the like, and image editing such as synthesis, erasure, connection, replacement, and fitting. Although not particularly described in the description of the present embodiment, a dedicated circuit for processing and editing audio information may be provided as in the above-described image processing and image editing.

Accordingly, the present image forming apparatus can be used as a television broadcast display device, a video conference terminal device, an image editing device that handles still images and moving images, a computer terminal device, an office terminal device such as a word processor,
It is possible to combine functions such as game machines with one unit,
It has a very wide range of applications for industrial or consumer use.

FIG. 20 shows only an example of the configuration of an image forming apparatus using a display panel using a surface conduction electron-emitting device as a driving element. It goes without saying that the present invention is not limited to this.

For example, among the components shown in FIG. 20, circuits relating to functions that are unnecessary for the purpose of use may be omitted.
Conversely, additional components may be added depending on the purpose of use. For example, when the present image forming apparatus is applied as a videophone, it is preferable to add a transmission / reception circuit including a television camera, an audio microphone, an illuminator, and a modem to the components.

In the present image forming apparatus, in particular, since the display panel 201 according to the present invention can be easily made thin, the depth of the display device can be reduced. In addition, since it is easy to enlarge the screen, the brightness is high, and the viewing angle characteristics are excellent, it is possible to display an image full of a sense of reality and full of power with good visibility.

[0242]

As described above, according to the image display device of the present invention provided with the getter element composed of the surface conduction electron-emitting device, the following effects can be obtained .

(1) Since the getter treatment can be performed without using a getter material, a drive composed of a cold cathode type electron-emitting device (especially a surface conduction type electron-emitting device or the like) whose electron emission characteristics are easily influenced by the surface condition. The lowering of the degree of vacuum and the lowering of the quality of the vacuum can be prevented without affecting the element for use, such as adhesion of a getter material. As a result, deterioration of the electron emission characteristics of the electron source can be prevented, and a stable and high-quality image can be obtained over a long period of time.

(2) Since getter elements are small and a plurality of getter elements can be arranged relatively freely, necessary and sufficient getter capability can be easily ensured even in the case of a large-area electron source or image forming apparatus. .

(3) Since there is no problem of adhesion of the getter material, the driving element and the getter element can be arranged in the same space, and the effective getter function can be enhanced.

(4) Since the getter process can be repeatedly performed, it is possible to easily cope with the deterioration of the degree of vacuum and the quality of vacuum over time.

As described above, according to the present invention, a large-area flat display which can deal with a color image and has high definition and high display quality is realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a planar surface conduction electron-emitting device suitable as a driving device and a getter device according to the present invention.

FIG. 2 is a diagram showing a configuration example of a vertical surface conduction electron-emitting device suitable as a driving device and a getter device according to the present invention.

FIG. 3 is a cross-sectional view for explaining an example of a method for manufacturing the flat surface conduction electron-emitting device of FIG.

FIG. 4 is an example of a voltage waveform used for a forming process.

FIG. 5 is a schematic diagram of a measurement evaluation system for measuring electron emission characteristics of a surface conduction electron-emitting device.

FIG. 6 is a diagram showing a typical example of the relationship between the emission current Ie and the device current If and the device voltage Vf of the surface conduction electron-emitting device.

FIG. 7 is a schematic diagram illustrating an example of an electron source having a simple matrix arrangement according to the present invention.

FIG. 8 is a partially cutaway perspective view showing a schematic configuration of a display panel provided with an electron source having a simple matrix arrangement according to the present invention.

FIG. 9 is a diagram illustrating a configuration example of a fluorescent film used for a display panel.

FIG. 10 is a block diagram illustrating an example of a driving circuit of an image forming apparatus that performs image display according to an NTSC television signal.

FIG. 11 is a schematic diagram illustrating an example of a trapezoidal-shaped electron source according to the present invention.

FIG. 12 is a partially cutaway perspective view showing a schematic configuration of a display panel including a trapezoidal-shaped electron source according to the present invention.

FIG. 13 is a partial plan view of an electron source having a simple matrix arrangement shown in the first embodiment.

FIG. 14 is a partial cross-sectional view of the electron source of FIG.

15 is a cross-sectional view for explaining a manufacturing process of the electron source in FIG.

FIG. 16 is a diagram for explaining a manufacturing process of the planar cold cathode electron-emitting device used for the electron source driving device shown in the third embodiment.

FIG. 17 is a partial cross-sectional view of an image forming apparatus according to a fourth embodiment.

FIG. 18 is a partial cross-sectional view of the image forming apparatus according to the fifth embodiment.

FIG. 19 is a partial cross-sectional view of an image forming apparatus according to a sixth embodiment.

FIG. 20 is a block diagram of an image forming apparatus according to a seventh embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Electron emission part 3 Conductive thin film 4, 5 Device electrode 21 Step forming member 50 Ammeter for measuring device current If flowing through conductive thin film 3 51 Device voltage Vf is applied to surface conduction type electron-emitting device Power supply 52 for measuring the emission current Ie emitted from the electron emission section 2 53 high voltage power supply for applying a voltage to the anode electrode 54 54 for capturing the electrons emitted from the electron emission section 2 Anode electrode 55 Vacuum device 56 Exhaust pump 102 X-direction wiring connected to driving element 104 103 Y-direction wiring connected to driving element 104 and getter element 601 104 Driving element 105 Connection 111 Rear plate 112 Support frame 113 Glass substrate 114 Fluorescent film 115 Metal back 116 Face plate Hv High voltage terminal 118 Enclosure 121 Black conductive material 122 Phosphor 201 Display panel 202 Scanning circuit 203 Control circuit 204 Shift register 205 Line memory 206 Synchronization signal separation circuit 207 Modulation signal generator Va DC voltage source Vx DC voltage source 301 Display panel 302 Grid electrode 303 Electronics For passing through 304 Common wiring 401 Interlayer insulating film 402 Contact hole 403 Cr film 601 Getter element 602 X-directional wiring connected to getter element 601 700 Substrate 701 Insulating layer 702 W ₂ C film 703 Convex portion 704 Cold cathode 705 Gate electrode 706 Concave part 707 Insulator convex part 708 Eaves part 709 Cold cathode convex part tip 800 Getter room 801 Partition frame 802 Opening 900 Intermediate plate 1001 Driving display panel 201 Road 1002 display controller 1003 multiplexer 1004 decoder 1005 input-output interface circuit 1006 CPU 1007 image generating circuit 1008,1009,1010 image memory interface circuit 1011 image input interface circuit 1012 and 1013 TV signal receiving circuit 1014 input

Claims (2)

(57) [Claims] An electron source having a driving element comprising a cold cathode type electron emitting element, and an electron beam emitted from the electron source.
Image forming apparatus having a phosphor for forming an image by irradiation
In location, Ri Do from the surface conduction electron-emitting device having no phosphor facing position, et used as a getter for organic components in the vacuum
Image type, characterized by having a getter element that is
Equipment . 2. The image forming apparatus according to claim 1 , further comprising: a getter chamber communicating with a space in which the driving elements are arranged, wherein the getter elements are arranged in the getter chamber. Image forming apparatus.