JP2000235367A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce unevenness of density or luminance of an image so as to stabilize the image formed on an image forming member. SOLUTION: An inputted analog image signal is converted to the digital data of 8 bits per one color component of one pixel by an ADC 111. The digital image data for one scanning line are corrected by an operation circuit 113 so as to match with element efficiency of each electron emitting element to be corrected as the data of respective 9 bits. The corrected image data are supplied in parallel to a pulse width modulation circuit 106 as the data for one line, and thus, the corrected image data are supplied to current switches 108 as row unit driving pulse width modulation signals. The current switches 108 impart the currents based on each element efficiency for a time shown by the imparted pulse width signals to each element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus to which an electron source is applied, and more particularly to an image forming apparatus in which cold cathode electron-emitting devices are arranged in rows and columns in a matrix to form an image. is there.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a hot cathode device and a cold cathode device, are known. Among these, among the cold cathode devices, for example, a surface conduction type emission device, a field emission type device (hereinafter referred to as FE type), a metal / insulating layer / metal type emission device (hereinafter referred to as MIM type), and the like are known. I have.

[0003] As a surface conduction type emission element, for example,
M. I. Elinson, Radio E-ng. El
electron Phys. , 10, 1290, (196
5) and other examples described later are known.

The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. As this surface conduction type emission element, Sn described by Elinson et al.
In addition to those using an O2 thin film, those using an Au thin film [G. Dittmer: "Thin Solid Fi
lms ", 9,317 (1972)] and In2O3 /
According to SnO2 thin film [M. Hartwell an
d C.I. G. FIG. Fonstad: "IEEE Tran
s. ED Conf. , 519 (1975)] and those using carbon thin films [Hisashi Araki et al .: Vacuum, Vol. 26,
No. 1, 22 (1983)].

[0005] As a typical example of the element structure of these surface conduction electron-emitting devices, FIG. Hartwel
1 shows a plan view of an element according to the present invention. In FIG.
Reference numeral 1 denotes a substrate, and reference numeral 3004 denotes a conductive thin film made of a metal oxide formed by sputtering. The conductive thin film 3004 is formed in an H-shaped planar shape as shown. An electron emission portion 3005 is formed by performing an energization process called energization forming described later on the conductive thin film 3004. The interval L in the figure is 0.5 to 1 [mm], and W is
It is set at 0.1 [mm]. In addition, for convenience of illustration, the electron emitting portion 3005 is shown in a rectangular shape at the center of the conductive thin film 3004, but this is a schematic one, and the position and shape of the actual electron emitting portion are faithfully represented. Not necessarily.

[0006] M. In the above-described surface conduction electron-emitting device including the device by Hartwell et al., The electron-emitting portion 3005 is formed by subjecting the conductive thin film 3004 to an energization process called energization forming before electron emission.
It was common to form That is, the energization forming means energizing by applying a constant DC voltage to both ends of the conductive thin film 3004, or a DC voltage which is boosted at a very slow rate of, for example, about 1 V / min.
The electron emitting portion 30 in a state where the conductive thin film 3004 is locally destroyed, deformed or deteriorated, and is in an electrically high resistance state.
05 is formed. Note that a part of the conductive thin film 3004 that has been locally broken, deformed, or altered includes
Cracks occur. When an appropriate voltage is applied to the conductive thin film 3004 after the energization forming, electron emission is performed in the vicinity of the crack.

[0007] Examples of the FE type are described in, for example, W.S. P.
Dyke & W. W. Dolan, "Fie-ld em
issue ", Advance in Electr
on Physics, 8, 89 (1956), or C.I. A. Spindt, "Physicalpr
operations of thin-film figure
ld emissioncathodes with
molybdenium cones ", J. App.
l. Phys. , 47, 5248 (1976).

As a typical example of the FE type device configuration, FIG. A. 1 shows a cross-sectional view of a device by Spindt et al. In the figure, reference numeral 3010 denotes a substrate;
Is an emitter wiring made of a conductive material, 3012 is an emitter cone, 3013 is an insulating layer, and 3014 is a gate electrode. This device comprises an emitter cone 3012 and a gate electrode 3
By applying an appropriate voltage during 014, field emission is caused from the tip of the emitter cone 3012.

As another element structure of the FE type, FIG.
There is also an example in which an emitter and a gate electrode are arranged on a substrate almost in parallel with the plane of the substrate, instead of the laminated structure as shown in FIG.

As an example of the MIM type, for example,
C. A. Mead, “Operation of tun
nel-emission Devices, J. et al. Ap
pl. Phys. , 32, 646 (1961). FIG. 26 shows a typical example of an MIM type device configuration.
Shown in The figure is a sectional view, in which 3020 is a substrate, 3021 is a lower electrode made of metal, 3022 is a thin insulating layer having a thickness of about 100 Å, 3023
Is an upper electrode made of a metal having a thickness of about 80 to 300 angstroms. In the MIM type, the upper electrode 3023
By applying an appropriate voltage between the upper electrode 3023 and the lower electrode 3021, electrons are emitted from the surface of the upper electrode 3023.

The above-mentioned cold cathode device can obtain electrons at a lower temperature than the hot cathode device, and therefore does not require a heater for heating. Therefore, the structure is simpler than that of the hot cathode element, and a fine element can be produced. Also,
Even if a large number of elements are arranged on a substrate at a high density, problems such as thermal melting of the substrate hardly occur. In addition, unlike the hot cathode device, which operates by heating the heater, the response speed is slow, and the cold cathode device also has the advantage that the response speed is fast.

For this reason, research for applying the cold cathode device has been actively conducted.

For example, the surface conduction electron-emitting device has the advantage of being able to form a large number of devices over a large area because it has a particularly simple structure and is easy to manufacture among the cold cathode devices. Therefore, for example, Japanese Patent Application Laid-Open No.
As disclosed in JP-A-332-332, a method for arranging and driving a large number of elements has been studied.

As for the application of the surface conduction electron-emitting device, for example, an image forming apparatus such as an image display device and an image recording device, a charged beam source, and the like have been studied.

In particular, as an application to an image display device, for example, as disclosed in US Pat. No. 5,066,883, JP-A-2-257551 and JP-A-4-28137 by the present applicant, surface conduction is disclosed. An image display apparatus using a combination of a mold emission element and a phosphor that emits light by irradiation with an electron beam has been studied. An image display device using a combination of a surface conduction electron-emitting device and a phosphor is expected to have better characteristics than other conventional image display devices. For example, compared to a liquid crystal display device that has become widespread in recent years, it can be said that it is superior in that it does not require a backlight because it is a self-luminous type and that it has a wide viewing angle.

A method of driving a large number of FE types is disclosed in US Pat. No. 4,904,89 by the present applicant.
5 is disclosed. Further, as an example in which the FE type is applied to an image display device, for example, R.F. The flat panel display reported by Meyer et al. Is known. [R. Mey
er: "Recent Development
Microtips Display at LET
I ", Tech. Digest of 4th In
t. Vacuum Microele-troni
cs Conf. , Nagahama, pp .; 6-9
(1991)] Further, an example in which a number of MIM types are arranged and applied to an image display device is disclosed in, for example, Japanese Patent Application Laid-Open No.
-55738.

[0017]

SUMMARY OF THE INVENTION The present inventors have developed various materials, including those described in the above-mentioned prior art.
We have tried cold cathode devices with manufacturing method and structure. Furthermore, research has been conducted on a multi-electron beam source in which a large number of cold cathode devices are arranged, and on an image display device using the multi-electron beam source.

The inventors have tried a multi-electron beam source by an electric wiring method shown in FIG. 27, for example. That is, it is a multi-electron beam source in which a large number of cold cathode devices are two-dimensionally arranged and these devices are wired in a matrix as shown.

In the figure, 4001 schematically shows a cold cathode element, 4002 shows a wiring in a row direction, and 4003 shows a wiring in a column direction. Row direction wiring 4002 and column direction wiring 400
3 actually has a finite electrical resistance,
In the drawing, they are shown as wiring resistances 4004 and 4005. The above-described wiring method is called simple matrix wiring.

Although a 6 × 6 matrix is shown for convenience of illustration, the size of the matrix is not limited to this. For example, in the case of a multi-electron beam source for an image display device, a desired image display is performed. Elements that are sufficient to perform are arranged and wired.

In a multi-electron beam source in which cold cathode elements are arranged in a simple matrix, a row-directional wiring 4002 and a column-directional wiring 400 are required to output a desired electron beam.
3 is applied with an appropriate electric signal. For example, to drive one row of the cold cathode devices in the matrix, a selection voltage Vs is applied to the row direction wiring 4002 of the selected row,
At the same time, the non-selection voltage Vns is applied to the row direction wiring 4002 of the non-selected row. In synchronization with this, the column direction wiring 4003
Is applied with a drive voltage Ve for outputting an electron beam. According to this method, wiring resistances 4004 and 4004
If the voltage drop due to 5 is ignored, the voltage of Ve-Vs is applied to the cold cathode elements of the selected row, and the voltage of Ve-Vns is applied to the cold cathode elements of the non-selected rows. V
If e, Vs, and Vns are set to voltages of appropriate magnitudes, an electron beam of a desired intensity should be output only from the cold cathode elements in the selected row, and a different drive voltage Ve is applied to each of the column wirings. If applied, each of the elements in the selected row should output a different intensity electron beam. Further, if the length of time during which the drive voltage Ve is applied is changed, the length of time during which the electron beam is output should be changed.

Therefore, a multi-electron beam source having a cold-cathode element arranged in a simple matrix wiring has various applications. For example, if an electric signal corresponding to image information is appropriately applied, it is suitable as an electron source for an image display device. Can be used.

However, in a multi-electron beam source in which cold cathode devices are arranged in a simple matrix, the following problems actually occur.

That is, when the voltage source is actually connected to the multi-electron source and driven by the above-described voltage application method, a voltage drop occurs due to the wiring resistance, so that the voltage effectively applied to each electron-emitting device is generated. The problem that it fluctuated occurred.

The first cause of the variation in the voltage applied to each element is that, in the simple matrix wiring, the wiring length is different for each electron-emitting device (ie, the wiring resistance is different for each element). Can be

Second, the wiring resistance 4004 of each part of the row wiring
Is not uniform. This occurs because the current branches and flows from the row wiring of the row to be selected to each of the electron-emitting devices connected to the row, and the magnitude of the current flowing through each of the wiring resistors 4004 is not uniform.

Third, the voltage drop caused by the wiring resistance varies depending on the driving pattern (display pattern in the case of an image display device).

If the voltage applied to each electron-emitting device varies due to the above reasons, the intensity of the electron beam output from each electron-emitting device deviates from a desired value, which is inconvenient in application. Met. For example, when applied to an image display device, the luminance of a display image becomes non-uniform or the luminance fluctuates depending on the display image pattern.

Further, since the voltage variation tends to become more pronounced as the size of the simple matrix increases, it also becomes a factor limiting the number of pixels in the case of an image display device.

As a result of earnest research in view of such points,
The present inventors have already tried a driving method different from the above-described voltage application method.

That is, when driving a multi-electron beam in which the electron-emitting devices are arranged in a simple matrix wiring, the column wiring is not connected to a voltage source for applying a driving voltage Ve, but is used to output a desired electron beam. This is a method of driving by connecting a current source for supplying a necessary current. This method controls the magnitude of the emission current Ie by controlling the magnitude of the element current If.

That is, the magnitude of the current If flowing through each electron-emitting device is determined with reference to the (device current If) vs. (emission current Ie) characteristics of the electron-emitting device, and the magnitude of the current If is determined by a current source connected to the column wiring. Supply. More specifically, a memory storing (device current If) vs. (emission current Ie) characteristics, an arithmetic unit for determining the device current If to flow,
The drive circuit may be configured by combining an electric circuit such as a control current source. Among them, the control current source may use a circuit form in which the magnitude of the element current If to be passed is once converted into a voltage signal and then converted into a current by a voltage / current conversion circuit. According to this method, compared to the method of driving by connecting the voltage source described above, even if a voltage drop occurs in the wiring resistance, it is less affected by the voltage drop. A significant effect was observed in reducing.

However, the method described below also occurs in a method of driving by connecting a current source. That is, when a multi-electron source composed of a large number of elements is created, the (element current If) versus (emission current Ie) characteristics of the elements vary for various reasons. For example, in the case of a surface conduction electron-emitting device, the causes include a variation in resistance including an electron-emitting portion before forming, a voltage drop due to wiring resistance at the time of activation, and the like.

Accordingly, an object of the present invention is to make it possible to form a good image with less unevenness by uniformly outputting an electron beam from a multi-electron source having a large number of electron-emitting devices wired in a matrix. It is intended to provide a forming apparatus.

[0035]

In order to solve the above problems, for example, an image forming apparatus of the present invention has the following arrangement. That is, the image forming apparatus of the present invention includes a multi-electron source in which a plurality of cold cathode elements are arranged in a matrix using row wirings and column wirings, and an electron emitting element in a position facing the multi-electron beam source. An image forming apparatus having an image forming member that forms an image by being irradiated with an electron beam from a scanner, a scanning unit connected to the row wiring, and a modulation unit connected to the column wiring. Means for storing the efficiency of the element, and means for calculating correction data to be added to the luminance data based on the stored efficiency, wherein the modulation means is based on a leak current of the element measured in advance. The drive pulse output is modulated according to the image data by comprising a current source that outputs the stored current value, a pulse width modulation circuit, and a current switch that is turned on and off by this. A portion that consists of the portion is determined according to the variation of the individual elements of the multi-electron source.

Here, the luminance data may be digital luminance data separated from an input digital image signal, or a luminance signal separated from an input analog image signal may be sampled into digital luminance data. The converted version may be used.

The corrected luminance data is as follows:
There are cases where the number of bits is larger than the number of bits of the luminance data before correction, and where the luminance data before correction is equal to or smaller than the number of data bits of the luminance data before correction.

The cold cathode device of the present invention may be any of a surface conduction type emission device, an FE type emission device and a MIM type emission device.

[0039]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

<Configuration of Display Panel and Manufacturing Method> First, a specific example of a configuration and a manufacturing method of the display panel of the image display device in the embodiment will be described.

FIG. 13 is a perspective view of the display panel used in the embodiment, in which a part of the panel is cut away to show the internal structure.

In the figure, 1005 is a rear plate, 1006
Is a side wall, 1007 is a face plate, 1005
1007 form an airtight container for maintaining the inside of the display panel at a vacuum.

Here, when assembling the airtight container, it is necessary to seal the joints of the members in order to maintain sufficient strength and airtightness. Sealing was achieved by firing in an atmosphere at 400 to 500 degrees Celsius for 10 minutes or more. A method of evacuating the inside of the airtight container to a vacuum will be described later.

The rear plate 1005 has a substrate 1001
Is fixed, but the cold cathode device 1002 is provided on the substrate.
N × M are formed. (N and M are positive integers of 2 or more and are appropriately set according to the target number of display pixels. For example, in a display device for displaying high-definition television, N = 3000, M It is desirable to set a number equal to or greater than 1000. In the present embodiment, N = 3072 and M = 1024.)
The cold cathode elements are arranged in a simple matrix by M row-directional wirings 1003 and N column-directional wirings 1004. The portion constituted by 1001 to 1004 is called a multi-electron beam source. The manufacturing method and structure of the multi-electron beam source will be described later in detail.

In this embodiment, the multi electron beam source substrate 1001 is fixed to the rear plate 1005 of the airtight container.
01 has sufficient strength, the substrate 10 of the multi-electron beam source is used as a rear plate of the hermetic container.
01 itself may be used.

On the lower surface of the face plate 1007, a fluorescent film 1008 is formed. Since the present embodiment is a color display device, the fluorescent film 1008 has C
Phosphors of three primary colors of red, green and blue used in the field of RT are separately applied. The phosphor of each color is, for example, as shown in FIG.
As shown in FIG. 4A, black conductors 1010 are provided in stripes, and black conductors 1010 are provided between the stripes of the phosphor. The purpose of providing the black conductor 1010 is to prevent the display color from shifting even if the electron beam irradiation position is slightly shifted, and to prevent the reflection of external light to prevent the display contrast from lowering. And preventing charge-up of the fluorescent film by the electron beam. Although graphite is used as a main component for the black conductor 1010, any other material may be used as long as it is suitable for the above purpose.

FIG. 1 shows how to paint the three primary color phosphors.
The arrangement is not limited to the stripe arrangement shown in FIG. 4A, and may be, for example, a delta arrangement as shown in FIG.

When a monochrome display panel is formed, a monochromatic phosphor material may be used for the phosphor film 1008, and a black conductive material may not be necessarily used.

A metal plate 1009 known in the field of CRT is provided on the surface of the fluorescent film 1008 on the rear plate side.
Is provided. The purpose of providing the metal back 1009 is
A part of the light emitted from the fluorescent film 1008 is specularly reflected to improve the light utilization rate, or the fluorescent film 1008
8 to protect it, to act as an electrode for applying an electron beam acceleration voltage, and to act as a conductive path for excited electrons of the fluorescent film 1008. The metal back 1009 was formed by forming a fluorescent film 1008 on the face plate substrate 1007, smoothing the surface of the fluorescent film, and vacuum-depositing Al thereon.
Note that when a fluorescent material for low voltage is used for the fluorescent film 1008, the metal back 1009 is not used.

Although not used in this embodiment, for the purpose of applying an acceleration voltage or improving the conductivity of the fluorescent film, a transparent material made of, for example, ITO is provided between the face plate substrate 1007 and the fluorescent film 1008. Electrodes may be provided.

Dx1 to Dxm, Dy1 to Dyn, and Hv are electric connection terminals having an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown). Dx1 to Dxm are the row wirings 10 of the multi-electron beam source.
03, Dy1 to Dyn are the column direction wirings 1004 of the multi-electron beam source, and Hv is the metal back 1 of the face plate.
009 electrically.

In order to evacuate the inside of the hermetic container to a vacuum, after assembling the hermetic container, an exhaust pipe (not shown) and a vacuum pump are connected, and the inside of the hermetic container is raised to 10 −7 [T
orr]. Thereafter, the exhaust pipe is sealed, but a getter film (not shown) is formed at a predetermined position in the airtight container immediately before or after the sealing in order to maintain the degree of vacuum in the airtight container. The getter film is, for example, a film formed by heating and depositing a getter material containing Ba as a main component by a heater or high-frequency heating,
Due to the adsorption action of the getter film, the inside of the airtight container is 1 × 10−5 or 1 × 10−7 [Torr].
Is maintained at a vacuum degree.

The basic configuration and manufacturing method of the display panel according to the present embodiment have been described above.

Next, a method of manufacturing the multi-electron beam source used for the display panel of the above embodiment will be described. The material, shape, and manufacturing method of the cold cathode device are not limited as long as the multi-electron beam source used for the image display device of the present invention is an electron source in which cold cathode devices are arranged in a simple matrix. Therefore, for example, a cold cathode device such as a surface conduction type emission device, an FE type, or an MIM type can be used.

However, in a situation where a display device having a large display screen and an inexpensive display device is required, among these cold cathode devices, a surface conduction type emission device is particularly preferable. That is, in the FE type, since the relative position and shape of the emitter cone and the gate electrode greatly affect the electron emission characteristics, extremely high-precision manufacturing technology is required, but this achieves a large area and a reduction in manufacturing cost. Is a disadvantageous factor. In the MIM type, it is necessary to make the thickness of the insulating layer and the upper electrode thin and uniform, which is also a disadvantageous factor in achieving a large area and a reduction in manufacturing cost. On the other hand, since the surface conduction electron-emitting device has a relatively simple manufacturing method, it is easy to increase the area and reduce the manufacturing cost. In addition, the inventors have found that among the surface conduction electron-emitting devices, those in which the electron-emitting portion or its peripheral portion is formed of a fine particle film have particularly excellent electron-emitting characteristics and can be easily manufactured. Therefore, it can be said that it is most suitable for use in a multi-electron beam source of a high-luminance, large-screen image display device. Therefore, in the display panel of the above embodiment, a surface conduction electron-emitting device in which the electron-emitting portion or its peripheral portion is formed of a fine particle film is used. Therefore, the basic configuration, manufacturing method and characteristics of a suitable surface conduction electron-emitting device will be described first, and then the structure of a multi-electron beam source in which a large number of devices are arranged in a simple matrix will be described.

<Suitable Device Configuration and Manufacturing Method of Surface Conduction Emission Device> A typical configuration of a surface conduction electron-emitting device in which an electron-emitting portion or its peripheral portion is formed of a fine particle film is a flat type or a vertical type. Kinds are given.

<Plane type surface conduction electron-emitting device> First, the structure and manufacturing method of a plane type surface conduction electron-emitting device will be described. FIG. 15 is a plan view (a) and a cross-sectional view (b) for describing the configuration of a planar surface conduction electron-emitting device. In the figure, 1101 is a substrate, 1102 and 1103 are device electrodes, 1104 is a conductive thin film, 1105
Are electron-emitting portions formed by an energization forming process;
Reference numeral 113 denotes a thin film formed by the activation process.

As the substrate 1101, for example, various glass substrates such as quartz glass and blue plate glass, various ceramics substrates such as alumina, or an insulating layer made of, for example, SiO ₂ is formed on the various substrates described above. A laminated substrate or the like can be used.

The device electrodes 1102 and 1103 provided on the substrate 1101 in parallel with the substrate surface are formed of a conductive material. For example, N
i, Cr, Au, Mo, W, Pt, Ti, Cu, Pd,
A material such as Ag or the like, an alloy of these metals, a metal oxide such as In ₂ O ₃ —SnO ₂ , or a semiconductor such as polysilicon may be appropriately selected and used. . An electrode can be easily formed by using a combination of a film forming technique such as vacuum evaporation and a patterning technique such as photolithography and etching. However, the electrode can be formed by other methods (for example, printing technique). I can't wait.

The shapes of the device electrodes 1102 and 1103 are appropriately designed according to the application purpose of the electron-emitting device.
Generally, the electrode spacing L is usually designed by selecting an appropriate value from the range of several hundreds of angstroms to several hundreds of micrometers. It is in the range of ten micrometers. Further, regarding the thickness d of the device electrode,
Usually, an appropriate numerical value is selected from the range of several hundred angstroms to several micrometers.

A fine particle film is used for the conductive thin film 1104. The fine particle film mentioned here is a film containing many fine particles as a constituent element (including an island-shaped aggregate).
I mean If you examine the microparticle film microscopically, usually
A structure in which the individual fine particles are spaced apart, a structure in which the fine particles are adjacent to each other, or a structure in which the fine particles overlap each other is observed.

The particle size of the fine particles used in the fine particle film is in the range of several Angstroms to several thousand Angstroms, and preferably in the range of 10 Angstroms to 200 Angstroms. Further, the thickness of the fine particle film is appropriately set in consideration of various conditions described below. That is, the device electrode 11
02, or 1103, conditions necessary for satisfactorily performing energization forming described later, conditions necessary for setting the electric resistance of the fine particle film itself to an appropriate value described later. , And so on.

Specifically, the setting is made in the range of several angstroms to several thousand angstroms, and the most preferable is between 10 angstroms and 500 angstroms.

Materials that can be used to form the fine particle film include, for example, Pd, Pt, Ru, Ag,
Au, Ti, In, Cu, Cr, Fe, Zn, Sn, T
a, W, Pb, and other metals, PdO, S
_{nO2, In 2 O 3, PbO} , and oxides including Sb ₂ O _{3, etc., HfB 2, ZrB 2, LaB} 6, C
Borides such as eB ₆ , YB ₄ , GdB ₄ , etc., TiC, ZrC, HfC, TaC, SiC, WC,
And other carbides, TiN, ZrN, Hf
Nitrides such as N, etc., semiconductors such as Si, Ge, etc., carbon, and the like are listed, and are appropriately selected from these.

As described above, the conductive thin film 1104 is formed of a fine particle film.
It was set to be included in the range of 10 3 to 10 7 [Ohm / sq].

The conductive thin film 1104 and the device electrode 11
Since it is desirable that the wires 02 and 1103 be electrically connected well, they have a structure in which a part of each overlaps with the other. In the example of FIG.
Although the substrate, the device electrode, and the conductive thin film are stacked in this order from the bottom, in some cases, the substrate, the conductive thin film, and the device electrode may be stacked in this order from the bottom.

The electron emitting portion 1105 is a crack-like portion formed in a part of the conductive thin film 1104, and has a higher electrical resistance than the surrounding conductive thin film. The crack is formed by performing a later-described energization forming process on the conductive thin film 1104. Fine particles having a particle size of several Angstroms to several hundred Angstroms may be arranged in the crack. Since it is difficult to accurately and accurately show the actual position and shape of the electron-emitting portion, they are schematically shown in FIG.

The thin film 1113 is a thin film made of carbon or a carbon compound, and covers the electron emitting portion 1105 and its vicinity. The thin film 1113 is formed by performing an energization activation process described later after the energization forming process.

The thin film 1113 is made of any one of single-crystal graphite, polycrystalline graphite, and amorphous carbon, or a mixture thereof, and has a thickness of 500 [Å] or less, but 300 [Å] or less. Is more preferred.

Since it is difficult to accurately show the actual position and shape of the thin film 1113, it is schematically shown in FIG. Also, in the plan view (a), the thin film 11
13 shows a device in which a part of the device 13 is removed.

The basic structure of the preferred element has been described above. In the embodiment, the following element is used.

That is, a soda lime glass was used for the substrate 1101, and a Ni thin film was used for the device electrodes 1102 and 1103. The thickness d of the device electrode was 1000 [angstrom], and the electrode interval L was 2 [micrometer].

Pd or P as the main material of the fine particle film
Using dO, the thickness of the fine particle film was set to about 100 [angstrom], and the width W was set to 100 [micrometer].

Next, a method of manufacturing a suitable flat surface conduction electron-emitting device will be described.

FIGS. 16 (a) to 16 (d) are cross-sectional views for explaining the manufacturing process of the surface conduction electron-emitting device, and the notation of each member is the same as in FIG.

1) First, as shown in FIG. 16A, device electrodes 1102 and 1103 are formed on a substrate 1101.

In forming, the substrate 1
After sufficiently washing 101 with a detergent, pure water and an organic solvent,
The material of the device electrode is deposited. (As a deposition method, for example, a vacuum film forming technique such as a vapor deposition method or a sputtering method may be used.) Thereafter, the deposited electrode material is patterned by using a photolithography / etching technique, and ), A pair of device electrodes (1102 and 1
103) is formed.

2) Next, a conductive thin film 1104 is formed as shown in FIG.

In the formation, first, an organic metal solution is applied to the substrate shown in FIG. 2A, dried, heated and baked to form a fine particle film, and then patterned into a predetermined shape by photolithography and etching. I do. here,
The organic metal solution is a solution of an organic metal compound containing a material of fine particles used for the conductive thin film as a main element. (Specifically, in the present embodiment, Pd is used as a main element. In the embodiment, a dipping method is used as a coating method, but other methods such as a spinner method and a spray method may be used.) In addition, as a method for forming a conductive thin film made of a fine particle film, other than the method of applying the organometallic solution used in the present embodiment, for example, a vacuum evaporation method, a sputtering method, or a chemical vapor deposition method may be used. Sometimes used.

3) Next, as shown in FIG. 10C, a forming power supply 1110 supplies the device electrodes 1102 and 1102 with each other.
3, an appropriate voltage is applied, and an energization forming process is performed to form the electron-emitting portion 1105.

The energization forming treatment is to energize the conductive thin film 1104 made of a fine particle film, to appropriately break, deform, or alter a part of the conductive thin film 1104, thereby changing the structure to a structure suitable for emitting electrons. This is the process that causes A portion of the conductive thin film made of a fine particle film that has been changed to a structure suitable for emitting electrons (that is, the electron emitting portion 110
In 5), an appropriate crack is formed in the thin film.
Note that the electrical resistance measured between the device electrodes 1102 and 1103 is significantly increased after the formation of the electron emission portions 1105 as compared to before the formation.

FIG. 17 shows an example of an appropriate voltage waveform applied from the forming power supply 1110 in order to explain the energization method in more detail. When forming a conductive thin film made of a fine particle film, a pulse-like voltage is preferable. In the case of this embodiment, a triangular wave pulse having a pulse width T1 is continuously generated at a pulse interval T2 as shown in FIG. Was applied. At that time, the peak value Vpf of the triangular wave pulse was sequentially increased. In addition, monitor pulses Pm for monitoring the state of formation of the electron-emitting portion 1105 were inserted at appropriate intervals between the triangular-wave pulses, and the current flowing at that time was measured by the ammeter 1111.

In the embodiment, for example, in a vacuum atmosphere of about 10 −5 [torr], for example, the pulse width T1 is 1 [millisecond], the pulse interval T2 is 10 [millisecond], and the peak value Vpf is The voltage was increased by 0.1 [V] for each pulse. Then, the monitor pulse Pm was inserted at a rate of one every time five triangular waves were applied. The monitor pulse voltage Vpm was set to 0.1 [V] so as not to adversely affect the forming process. Then, when the electric resistance between the element electrodes 1102 and 1103 becomes 1 × 10 6 [ohm], that is, the current measured by the ammeter 1111 when the monitor pulse is applied becomes 1 × 10 −7 [A] or less. At this stage, the energization related to the forming process was terminated.

The above method is a preferable method for the surface conduction electron-emitting device of this embodiment. For example, the design of the surface conduction electron-emitting device such as the material and film thickness of the fine particle film or the element electrode interval L is changed. In such a case, it is desirable to appropriately change the energization conditions accordingly.

4) Next, as shown in FIG. 16 (d), an appropriate voltage is applied between the element electrodes 1102 and 1103 from the activation power supply 1112, and an energization activation process is performed to perform electron emission characteristics. Make improvements.

The energization activation process is a process of energizing the electron-emitting portion 1105 formed by the energization forming process under appropriate conditions and depositing carbon or a carbon compound in the vicinity thereof. (In the figure, a deposit made of carbon or a carbon compound is schematically shown as a member 1113.) By performing the activation process, the emission current at the same applied voltage is typically smaller than that before the activation. Specifically, it can be increased by 100 times or more.

Specifically, 10 minus the fourth power to 1
By applying a voltage pulse periodically in a vacuum atmosphere within the range of 0 to the fifth power [torr], carbon or a carbon compound originating from an organic compound existing in the vacuum atmosphere is deposited. The deposit 1113 is any of single crystal graphite, polycrystalline graphite, and amorphous carbon, or a mixture thereof, and has a thickness of 500.
[Angstrom] or less, more preferably 300 [angstrom] or less.

FIG. 18A shows an example of an appropriate voltage waveform applied from the activation power supply 1112 in order to explain the energization method in more detail. In the present embodiment, the energization activation process is performed by applying a rectangular wave of a constant voltage periodically. Specifically, the voltage Vac of the rectangular wave is 14 [V],
The pulse width T3 is 1 [millisecond], and the pulse interval T4 is 10
[Milliseconds]. Note that the above-described energization conditions are preferable conditions for the surface conduction electron-emitting device of the present embodiment,
When the design of the surface conduction electron-emitting device is changed, it is desirable to appropriately change the conditions accordingly.

Reference numeral 1114 shown in FIG. 16D denotes an anode electrode for capturing the emission current Ie emitted from the surface conduction electron-emitting device. The anode electrode 1114 is connected to a DC high voltage power supply 1115 and an ammeter 1116. (Note that the substrate 1101
When the activation process is performed after the display panel is incorporated in the display panel, the phosphor screen of the display panel is connected to the anode electrode 1114.
Used as While the voltage is applied from the activation power supply 1112, the ammeter 1116 measures the emission current Ie to monitor the progress of the energization activation process.
12 is controlled. One example of the emission current Ie measured by the ammeter 1116 is shown in FIG. 18B. When the pulse voltage is started to be applied from the activation power supply 1112, the emission current Ie increases with the passage of time, but eventually saturates. And hardly increase. As described above, when the emission current Ie is substantially saturated, the application of the voltage from the activation power supply 1112 is stopped, and the energization activation process ends.

The above-mentioned energization conditions are preferable conditions for the surface conduction electron-emitting device of the present embodiment, and when the design of the surface conduction electron-emitting device is changed, the conditions should be changed accordingly. desirable.

As described above, the planar surface conduction electron-emitting device shown in FIG. 16E was manufactured.

<Vertical Surface Conduction Emitting Element> Next, another typical configuration of a surface conduction electron-emitting device in which the electron-emitting portion or its periphery is formed of a fine particle film, that is, a vertical surface-conduction emission device. The configuration of the element will be described.

FIG. 19 is a schematic sectional view for explaining the basic structure of the vertical type. In the figure, reference numeral 1201 denotes a substrate, 1
202 and 1203 are device electrodes, 1206 is a step forming member, 1204 is a conductive thin film using a fine particle film, 1205
Are electron-emitting portions formed by an energization forming process;
213 is a thin film formed by the activation process.

The difference between the vertical type and the flat type described above is that one of the device electrodes (1202) is provided on the step forming member 1206, and the conductive thin film 1204 is provided on the side surface of the step forming member 1206. It is in the point of coating. Therefore, the element electrode interval L in the planar type shown in FIG.
In the vertical type, the height is set as the step height Ls of the step forming member 1206. Note that the substrate 1201, the element electrode 120
2 and 1203, conductive thin film 120 using fine particle film
For 4, the materials listed in the description of the planar type can be used in the same manner. Step forming member 1
For 206, an electrically insulating material such as SiO2 is used.

Next, a method of manufacturing a vertical surface conduction electron-emitting device will be described. FIGS. 20A to 20F are cross-sectional views for explaining the manufacturing process, and the notation of each member is the same as that in FIG.

1) First, as shown in FIG. 20A, an element electrode 1203 is formed on a substrate 1201.

2) Next, as shown in FIG. 9B, an insulating layer for forming a step forming member is laminated. The insulating layer may be formed by laminating SiO2 by sputtering, for example, but other film forming methods such as vacuum deposition or printing may be used.

3) Next, as shown in FIG. 9C, an element electrode 1202 is formed on the insulating layer.

4) Next, as shown in FIG. 9D, a part of the insulating layer is removed by using, for example, an etching method to expose the element electrode 1203.

5) Next, as shown in FIG. 9E, a conductive thin film 1204 using a fine particle film is formed. For the formation, as in the case of the flat type, a film forming technique such as a coating method may be used.

6) Next, similarly to the case of the above-mentioned flat type, the energization forming process is performed to form an electron emission portion (the same process as the flat type energization forming process described with reference to FIG. 16C). 7) Next, as in the case of the flat type, a current activation process is performed to deposit carbon or a carbon compound near the electron emission portion. (A process similar to the planar energization activation process described with reference to FIG. 16D may be performed.) As described above, the vertical surface conduction electron-emitting device shown in FIG. Manufactured.

<Characteristics of Surface Conduction Emission Device Used in Display Device> The device configuration and manufacturing method of the planar and vertical surface conduction electron-emitting devices have been described above. Next, the characteristics of the device used in the display device will be described. Is described.

FIG. 21 shows typical examples of (emission current Ie) versus (device applied voltage Vf) characteristics and (device current If) versus (device applied voltage Vf) characteristics of the devices used in the display device. . Note that the emission current Ie is significantly smaller than the element current If, and it is difficult to show the same current on the same scale.
Since these characteristics are changed by changing design parameters such as the size and shape of the element, the two graphs are shown in arbitrary units.

The element used in the display device has the following three characteristics regarding the emission current Ie.

First, a certain voltage (this is referred to as a threshold voltage Vth
When a voltage of the above magnitude is applied to the element, the emission current Ie sharply increases. On the other hand, at a voltage lower than the threshold voltage Vth, the emission current Ie is hardly detected.

That is, the non-linear element has a clear threshold voltage Vth with respect to the emission current Ie.

Secondly, since the emission current Ie changes depending on the voltage Vf applied to the element, the emission current Ie depends on the voltage Vf.
The magnitude of e can be controlled.

Third, since the response speed of the current Ie emitted from the element is faster with respect to the voltage Vf applied to the element, the amount of charge of the electrons emitted from the element depends on the length of time during which the voltage Vf is applied. Can control.

Because of the above characteristics, the surface conduction electron-emitting device could be suitably used for a display device. For example, in a display device in which a large number of elements are provided corresponding to pixels of a display screen, if the first characteristic is used, display can be performed by sequentially scanning the display screen. That is,
The driving element has a threshold voltage Vt according to a desired light emission luminance.
h or higher, and a voltage lower than the threshold voltage Vth is applied to the non-selected elements. By sequentially switching the elements to be driven, the display screen can be sequentially scanned and displayed.

Further, since the emission luminance can be controlled by using the second characteristic or the third characteristic, gradation display can be performed.

<Structure of a Multi-Electron Beam Source in which Many Devices are Wired in a Simple Matrix> Next, a structure of a multi-electron beam source in which the above-mentioned surface conduction electron-emitting devices are arranged on a substrate and wired in a simple matrix will be described.

FIG. 22 is a plan view of the multi-electron beam source used for the display panel of FIG. On the substrate, surface conduction emission devices similar to those shown in FIG. 15 are arranged, and these devices are wired in a simple matrix by row-direction wiring electrodes 1003 and column-direction wiring electrodes 1004. Row direction wiring electrode 1003 and column direction wiring electrode 1
At the intersection of 004, an insulating layer (not shown) is provided between the electrodes.
Are formed, and electrical insulation is maintained.

FIG. 23 is a sectional view taken along the line AA ′ of FIG.
Shown in

Incidentally, the multi-electron source having such a structure is as follows.
After previously forming a row direction wiring electrode 1003, a column direction wiring electrode 1004, an interelectrode insulating layer (not shown), and a device electrode and a conductive thin film of a surface conduction electron-emitting device on a substrate,
Row direction wiring electrode 1003 and column direction wiring electrode 1004
The device was manufactured by supplying power to each element through the device and performing an energization forming process and an energization activation process.

<Display Driving Method and Correction Method> Next, a driving method and a correction method of the image display device according to the present embodiment will be described with reference to FIG.

In the figure, reference numeral 101 denotes the above-mentioned display panel, which is connected to an external electric circuit via terminals Dx1 to Dxm and Dy1 to Dyn. A high-voltage terminal Hv on the face plate is also connected to an external high-voltage power supply Va to accelerate emitted electrons. The terminals Dx1 to Dxm are used to sequentially drive the multi-electron beam sources provided in the above-mentioned panel, that is, the surface conduction electron-emitting devices arranged in a matrix of M rows and N columns, one row at a time. Are applied. On the other hand, to the terminals Dy1 to Dyn, a modulation signal for controlling the output electron beam of each element of the surface conduction electron-emitting device in one row selected by the scanning signal is applied.

Next, the scanning circuit 102 will be described.
This circuit includes M switching elements inside, and each switching element selects either the output pressure of the DC voltage source Vx or 0 [V] (ground level), and the terminal of the display panel 101 It is electrically connected to Dx1 to Dxm. Each switching element is
Although it operates based on a control signal Tscan output from the control circuit 103, in actuality, it can be easily configured by combining switching elements such as FETs.

In the case of the present embodiment, the DC voltage source Vx is not scanned based on the characteristics of the surface conduction electron-emitting device illustrated in FIG. 21 (electron emission threshold voltage is 8 [V]). It is set so as to output a constant voltage of 7 [V] so that the drive voltage applied to the element is equal to or lower than the electron emission threshold voltage.

Next, the flow of the input image signal will be described. The input composite image signal is converted by the decoder 110 into a luminance signal of three primary colors and a horizontal and vertical synchronizing signal (here, for the sake of explanation, the synchronizing signal TSYN
C).

Further, the control circuit 103 has a function of matching the operations of the respective units so that an appropriate display is performed based on an image signal input from the outside. Tsync
Based on the above, Tad, Tps, Adr
s, Tscan and Tsft and Tmry and Tm
od of each control signal.

On the other hand, the luminance signals of the three primary colors are input to an ADC (analog-to-digital converter) 111 and are converted into 8-bit digital signals at the timing of the sampling clock Tad. The number of bits at this time is determined according to the required number of gradations (the number of colors) of the image to be displayed. In the present embodiment, 256 bits for each of the RGB colors are used.
In order to realize gradation (about 16.7 million colors), it was decided to be 8 bits. The converted digital luminance signal is input to a P / S (parallel / serial) conversion circuit 112 in order to convert the digital luminance signal in order according to the pixel arrangement on the FP. The serially converted data (8 bits) is processed and corrected in the arithmetic circuit 113 based on the data of the efficiency correction table (LUT2) 115 stored in advance by a method described later. Here, since the correction data is added, the number of bits is increased to 9 bits and output.

The 9-bit serial data to which the correction data has been added is next input to the shift register 104.

The shift register 104 is for serially / parallel converting the digital signal input serially in time series for each line of an image, and is based on a control signal Tsft sent from the control circuit 103. (That is, the control signal Tsft may be a shift clock of the shift register 104). The data of one line of the serial / parallel-converted image (corresponding to the drive data of N electron-emitting devices) is output from the shift register 104 as N parallel signals Idl to Idn.

The latch circuit 105 is a storage device for storing data for one line of an image for a required time only.
The contents of Idl1 to Idn are stored as appropriate according to the control signal Tmry sent from the control circuit 103. The stored contents are output to pulse width modulation circuit # 106 as I'd1 to I'dn.

The pulse width modulation circuit 106 is for generating a pulse having a time width corresponding to each of the image data I'd1 to I'dn, and its output is a terminal Id ".
It is connected to the gate of the switch through 1 to Id "n. The timing signal tm from the control circuit 103
A voltage signal having a pulse width corresponding to the data is output in accordance with “od”.

The internal configuration will be described with reference to FIG.
Reference numeral 401 denotes a down counter in which n lines are arranged for the number of column wirings, and data input terminals are data lines I from the latch circuit,
d'1 to Id'n. The data load terminal LD is connected to a common line and a signal Tmod from the control circuit is provided.
, The countdown data is loaded from Id'1 to Id'n in accordance with the timing of Tmod. The counter clock clk is also commonly wired and connected to the clock output Pclk of the internal countdown clock generation circuit 402. The clock of the 402 clock generation circuit is generated by being reset by Tmod. The frequency of Pclk needs to be equal to or more than the count number of the counter of the Tmod signal (512 in this embodiment because it is a 9-bit counter). Set to double. With these settings, the data is loaded into the 401 down counter at the timing of Tmod, and at the same time, when the countdown is performed by the counter clock Pclk and it becomes 0, the clr signal becomes true (5 V). Since this signal switches the output of the current source by the gate terminal of the 108 current switch, current supply to the column wiring corresponding to this time is cut off, and pulse width modulation is realized.

The current switch 108 is a p-channel MOSF
ET is used to switch the output current of the current source 109 between the display panel 101 side and the ground side by the output of the pulse width modulation circuit.

Next, the current source 109 will be described with reference to FIGS. As shown in FIG. 4, the current source 109 includes n current sources 301, n D / A conversion circuits 306, and a line memory 307 set from leak current correction data measured by a method described later. The control voltage Vin is set by a voltage value obtained by converting the data stored in the line memory 307 by the D / A conversion circuit 306. In the present embodiment, the number of bits of the line memory is set to 9 bits so as to be sufficient for the above-described display gradation number 256. It is not limited. Each current source 301 is constituted by a current mirror circuit as shown in FIG. This circuit includes an operational amplifier 302, NP
It comprises an N transistor 303, a PNP transistor 304, and a setting resistor 305, and the output current Iout is expressed by the following equation with respect to the control voltage Vin.

Iout = Vin / Ri (Equation 1) Next, the details of the operation at the time of generating the correction data and the correction operation at the time of driving using the correction data will be described.

First, a procedure for creating a correction data LUT to be performed after the image forming apparatus is manufactured will be described. At this time,
The measuring device is shown in FIG.

At the time of LUT creation, the control circuit 504 performs timing control in accordance with data creation. At this time, the control circuit 504 generates a control signal so that the column selection drive circuit 511 generates a drive signal having a specific drive voltage and a specific pulse width for a specific pixel. The device current If flowing through the surface conduction electron-emitting device selected by the drive signal and the output of the scanning circuit is detected by a current monitor circuit 512 using a monitor resistor. At the same time, the electron emission current Ie is monitored and sent to the correction data creation circuit 513 together with the If monitor signal. This is performed for all surface conduction type emission devices.

The inventor paid attention to the strong correlation between the electron beam Ie output of the surface conduction electron-emitting device and the device current If flowing through the device, and proposed and implemented the following correction method.

First, the creation of the LUT 1 will be described with reference to FIG. When the LUT 1 is created, the drive lines Dx1, Dx2, Dx3,.
To In this state, the column selection drive circuit 511 generates a pulse voltage of +1/2 Vf to 7.5 V, which is a column half selection voltage. With this applied voltage, none of the elements is turned on, and the current monitor circuit 515 detects the element current flowing.

For example, the device current detected when the device at the position (M, N) is driven is the device current flowing when a voltage of + ／ Vf is applied to the m surface-conduction emission devices existing on the column N. Is the sum of

If1 = {If [+ 1 / 2Vf, (K, N)] (Equation 2) Here, Σ is the sum of K = 1,.
[+ 1 / 2Vf, (K, N)] is an element current flowing when a voltage of +1/2 Vf is applied to the element at the position (K, N).

As is clear from the If characteristics of the single element shown in FIG. 21, almost no If flows at a voltage of + 1 / 2Vf ≒ 7.5V. However, when the size of the simple matrix is increased and M and N exceed 100, the current of Expression 2 becomes a nonnegligible amount. When a current output driver drives a display panel in which surface conduction electron-emitting devices are arranged in a simple matrix structure, if such a current is present, the current will flow not in the selection device but in a device that has been subjected to a half-selection voltage. A desired element current cannot be passed through the element. Therefore, a current (hereinafter referred to as an invalid element current Ifn) that flows to the half-selected element during driving is measured and stored in the LUT 1 in advance. That is, an LUT having an m × n address space is prepared, and the reactive element current Ifn (M, N) observed when the element at the position (M, N) is selected is converted to the address (M, N) of the LUT.
N). When Ifn was actually observed, the observed Ifn almost coincided on the same column. So 1
LUT 1: 508 having an address space of × n was prepared, and Ifn data was observed and stored for each column.

Next, the creation of LUT2: 115 will be described with reference to FIG.
This will be described below. When creating the LUT2: 115, the drive lines Dx1, Dx2, Dx3,...
Dxm is controlled to select either the output voltage of Vx or 0 [V] (ground level) in the same manner as in image formation. In this state, the pulse width modulation circuit generates a pulse voltage of +1/2 Vf ≒ 7.5 V, which is a column half selection voltage. At this time, only the elements to which the row and column selection voltages are applied are selected and emit electrons. The correction data creation circuit 513 detects If and Ie monitor signals for each element.

For example, Ie and If detected when driving the element at the position (M, N) can be expressed as follows. Ie has a clear threshold voltage Vth (8 [V] in the device of the present embodiment), and electron emission occurs only when a voltage higher than Vth is applied. Therefore, Ie = Ie [+ Vf, (M, N)] (Equation 3) is detected. Here, Ie [+ Vf, (M, N)] is an electron emission current when a voltage of + Vf is applied to the element at the position (M, N).

On the other hand, the element current is equal to m−
The sum of the element current flowing when a voltage of + ／ Vf is applied to one surface conduction type emission element and the sum of the element current flowing when a voltage of + Vf is applied to the selected element at the position (M, N). .

If2 = {If [+ 1 / 2Vf, (K, N)] + If [+ Vf, [M, N] (Equation 4) where Σ is the sum up to K = 1,. .

From the observed value represented by Equation 4 and the data of LUT1 (Equation 2), the element current that truly flows through the selected element (M, N) can be estimated. That is, M and N are large (> 200)
In this case, by subtracting the value of Expression 2 from the value of Expression 4, an element current that truly flows to the selected element (M, N) (hereinafter referred to as Ifm) Ifm = If [+ Vf, (M, N)] (Expression 5) Is calculated.

The ratio of the electron emission current to the device current of each device (hereinafter referred to as efficiency η = Ie / Ifm) is stored in LUT2: 115 as a correction amount of the characteristic variation of each device. That is, an LUT having an m × n address space
Is prepared, and the efficiency η (M, N) of the element observed when the element at the position (M, N) is selected is converted to the address (M, N) of the LUT.
Stored in.

Next, the details of the correction using the correction data LUT1 and LUT2 will be described. In the present embodiment, gradation driving in which luminance data of an image signal is corrected based on the LUT 2 and variation in elements is compensated by pulse width modulation is performed.
Since the driving current of each column is determined based on No. 1, this will be described with reference to FIG.

As described above, in this embodiment, since the luminance data is 8 bits, the gradation of each of the three primary colors has a resolution of 256. Then, consider a case where the variation of the efficiency η is 0.1 to 0.2%. When the maximum luminance signal is input (255), the luminance signal is corrected in order to make the luminance from each element uniform.
When the pixel (M, N) is now accessed, Ifn (N) becomes 0.
When η (M, N) stored in 5 mA and LUT2: 115 is 0.15% and the correction data is obtained, the luminance signal is corrected by the following equation.

Corrected luminance signal 805: A (M, N) = luminance signal {(η (M, N) / ηmax) = 255} (0.15 / 0.2) = 340 This operation is performed by the division circuit 801 and the multiplication. This is realized by the circuit 803. The arithmetic circuit outputs the corrected luminance signal of the element (M, N) to the S / P conversion circuit. Further, the output of the S / P conversion circuit is supplied to the gate terminal of the current switch 108 through a pulse width modulation circuit that forms a pulse obtained by modulating the corrected luminance signal into a pulse width.

Next, a method of setting the current source shown in FIG. 4 based on the data of the LUT 1 will be described. First, it is assumed that the element current value is set to 1 mA from the required luminance of the display image, the average efficiency of the element, and the like. The reference voltage (that is, full span) of the D / A conversion circuit 306 is 5
V, and the setting resistor 305 is assumed to be 2.5 KΩ. At this time, if the leakage current Ifn (1) is 0.5 mA, it is necessary to set the output current to 1.5 mA. Therefore, according to Expression 2, Vin = Iout × Ri = 1.5 × 2.5K = 3. 75
Since V, the line memory only needs to store a digital value of 3.75 / 5 * 512 = 384.

Similarly, data to be stored in the line memory 307 is calculated based on Ifn (2) to Ifn (n).

FIG. 10 shows how an actual output waveform from the pulse width modulation circuit switches the current from the 109 current source to drive a desired element. Attention is paid to the drive line connected to the display panel Dy1, and luminance data input and LUT as shown in FIGS.
It is assumed that a signal is output. At this time, the current switch 1
FIG. 10 shows the waveform of the element current If switched by 08.
(G) shows the state of the emission current Ie in FIG.

When an image display apparatus was experimentally manufactured with the above-described configuration and settings, the distribution of luminance was small, leakage current of elements and variation in efficiency were corrected, and the number of gradations was not reduced. High quality images could be obtained.

In this embodiment, the video signal may be analog or digital, but a general analog signal is used as the current image signal. Further, as the serial / parallel conversion means, a shift register which can easily process digital signals is employed, but the present invention is not limited to this.

According to the present embodiment, it is possible to realize an excellent image display apparatus with a small variation in luminance distribution without reducing the necessary number of gradations by performing correction.

[Second Embodiment] The structures of the electron-emitting device and the panel according to the second embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

A driving method and a correction method of the image display device according to the second embodiment will be described with reference to FIG.

In the figure, the display panel 101 and the scanning circuit 10
2 is the same as in the first embodiment, and a description thereof will be omitted. The flow of the image signal is the same up to the point where the image signal is output from the 112P / S conversion circuit, and the description is omitted.

The operation of the control circuit 602 is the same as that of the first embodiment in that the operation of each unit is matched so that appropriate display is performed based on an image signal input from the outside, but Tad and Tps. , Adrs, Tscan
And Tsft and Tmry and Tmod control signals.

Serial converted data (8 bits)
Is processed and corrected in the arithmetic circuit 601 based on the data of the efficiency correction table (LUT) 115 stored in advance by the method described in the first embodiment. Here, the correction data and the original luminance data are output in chronological order by the method described later, so that the number of bits is output as 8 bits.

Next, the serial data of the correction data and the luminance data is input to the shift register 104. The operations of the shift register 104 and the latch circuit 105 are the same as those of the embodiment, and the description is omitted.

The pulse width modulation circuit 106 also operates, and the internal configuration is the same as that of the first embodiment.
The frequency of lk is multiplied by the number of counts of the counter of the Tmod signal (in the present embodiment, 2 times because of the 8-bit counter).
56) Although the above is necessary, in the present second embodiment, it is set to 260 times in consideration of each selection switching time.
The current switch 108 and the current source 109 are the same as in the first embodiment.

The details of the correction operation at the time of driving using the correction data will be described below.

In the second embodiment, the gradation driving is performed by correcting the luminance data of the image signal based on LUT2: 115 and compensating for variations in elements by pulse width modulation. explain.

As described above, in this embodiment, since the luminance data of each color component is 8 bits, the gradation of each of the three primary colors is 256.
Resolution. And the variation of the efficiency η is 0.1 to
Consider the case of 0.2%. When the maximum luminance signal is input (2
In 55), a corrected luminance signal is calculated to make the luminance from each element uniform. Now, when pixel (M, N) is accessed, I
When fn (N) is 0.5 mA and η (M, N) is 1.15%, the corrected luminance signal is generated by the following equation.

Corrected luminance signal 805: A (M, N) = luminance signal × (ηmax × η (M, N) −1) = 255 × (0.2 / 0.15-1) = 85 As described above, the operation is realized by the division circuit 1004, the subtraction circuit 1003, and the multiplication circuit 1001. The arithmetic circuit outputs the corrected luminance signal of the element (M, N) to the S / P conversion circuit. Further, the output of the S / P conversion circuit is supplied to the gate terminal of the current switch 108 through a pulse width modulation circuit that forms a pulse obtained by modulating the corrected luminance signal into a pulse width.

The method of setting the current source in FIG. 3 based on the data of the LUT 2 described above is the same as in the first embodiment, and a description thereof will be omitted.

FIG. 1 shows how the actual output waveform from the pulse width modulation circuit switches the current from the current source 109 to drive a desired element in the second embodiment.
2. Attention is paid to the drive line connected to the display panel Dy1, and it is assumed that luminance data input and LUT signal output as shown in FIGS. At this time, the switching circuit 1002 in the arithmetic circuit shown in FIG. 11 is controlled by Tcal as shown in FIG. That is, when Tcal is positive logic (high), the switching circuit 1002 outputs negative logic (lo)
In the case of w), it is switched to the 2 correction data side. That is, in the first half of the selection period, the luminance data remains unchanged, but in the second half, the correction data is output from the arithmetic circuit to the shift register as a corrected luminance signal. This is shown in FIG.
(G). The correction data for each column wiring is counted down at the same time as the readout by the pulse width modulation circuit at the timing Tmod shown in FIG. 12H through the silt register and the latch circuit. As a result, the current switch 108 is switched by the output of the pulse width modulation circuit. FIG. 12 (i) shows the waveform of the device current If, and FIG. 12 (j) shows the state of the emission current Ie.

When an image display device was experimentally manufactured with the above-described configuration and settings, as in the first embodiment, variation in the luminance distribution was small, and leakage current of elements and variations in efficiency were corrected. In addition, a high-quality image could be obtained without reducing the number of gradations. Further, in the present embodiment, the original luminance data and the correction data are time-pulse-modulated in a time series, so that a simpler circuit can be realized without increasing the number of bits of data after the correction operation circuit.

In this embodiment, the above-mentioned video signal may be analog or digital, but a general analog signal is used as the current image signal. Further, as the serial / parallel conversion means, a shift register which can easily process digital signals is employed, but the present invention is not limited to this.

According to the present embodiment, the luminance distribution is small without reducing the necessary number of gradations by performing the correction.
An excellent image display device was realized.

As described above, according to the first and second embodiments, in driving the multi-electron source in which the surface conduction electron-emitting devices are arranged in a matrix, the leakage current data and the efficiency data measured in advance are used. In addition, when correcting variations in elements, driving can be performed without reducing the number of gradations and without being affected by wiring resistance. Therefore, in an image forming apparatus to which the present invention is applied, excellent linearity of gradation and high-quality images can be realized.

[0169]

As described above, according to the present invention, an image formed on an image forming member can be made stable with little unevenness in density or luminance.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a drive circuit according to an embodiment.

FIG. 2 is a diagram illustrating a method of creating an LUT 1 according to the embodiment.

FIG. 3 is a diagram illustrating a method of creating an LUT 2 according to the embodiment.

FIG. 4 is a diagram illustrating a configuration of a current source according to the embodiment.

5 is a diagram showing a circuit configuration of each current source in FIG.

FIG. 6 is a diagram illustrating a circuit configuration of a pulse width modulation circuit according to the embodiment.

FIG. 7 is a diagram illustrating a correction data measurement circuit according to the embodiment.

FIG. 8 is a block diagram of an image forming apparatus according to a second embodiment.

FIG. 9 is a diagram illustrating a configuration of an arithmetic circuit according to the first embodiment.

FIG. 10 is a diagram illustrating a conversion transition of image data according to the first embodiment.

FIG. 11 is a diagram illustrating a configuration of an arithmetic circuit according to a second embodiment.

FIG. 12 is a diagram illustrating a conversion transition of image data according to the second embodiment.

FIG. 13 is a partially cutaway perspective view of the display panel in the embodiment.

FIG. 14 is a diagram showing a pattern formed on a fluorescent film in the embodiment.

FIG. 15 is a plan view and a cross-sectional view of a planar surface conduction electron-emitting device used in the embodiment.

FIG. 16 is a cross-sectional view showing a step of manufacturing a planar surface conduction electron-emitting device.

FIG. 17 is a diagram showing an applied voltage waveform in the energization forming process.

FIG. 18 is a diagram showing a change in an applied voltage waveform and a discharge current Ie in the activation process.

FIG. 19 is a sectional view of a vertical surface conduction electron-emitting device used in the embodiment.

FIG. 20 is a cross-sectional view showing a step of manufacturing a vertical surface conduction electron-emitting device.

FIG. 21 is a view showing typical characteristics of the surface conduction electron-emitting device used in the embodiment.

FIG. 22 is a plan view of a substrate of the multi-electron beam source used in the embodiment.

FIG. 23 is a partial cross-sectional view of the substrate of the multi-electron beam source used in the embodiment.

FIG. 24 is a diagram illustrating an example of a surface conduction electron-emitting device.

FIG. 25 is a diagram illustrating an example of an FE-type element.

FIG. 26 is a diagram showing an example of an MIM element.

FIG. 27 is a diagram illustrating a wiring method of the electron-emitting device.

Claims (16)

[Claims] 1. A multi-electron source in which a plurality of electron-emitting devices are arranged in a matrix using row wirings and column wirings, and an electron beam emitted from the electron-emitting device at a position facing the multi-electron source. An image forming member that forms an image by being performed, a row-by-row scanning unit connected to the row wiring,
A modulating means connected to the column wiring, receiving an image signal to be formed, and modulating the image signal; a means for storing a previously measured efficiency of the electron-emitting device; Means for calculating a corrected luminance signal from the luminance signal based on the efficiency, wherein the modulation means outputs a current value stored based on a leak current of the element measured in advance, and a pulse width. It is composed of a modulation circuit and a current switch that is turned on and off by this.
An image forming apparatus comprising: an element that is modulated in accordance with a luminance signal; and an element that is determined in accordance with efficiency variations of individual elements of the multi-electron source. 2. The image forming apparatus according to claim 1, wherein the luminance signal is a digital luminance signal separated from an input digital image signal. 3. The image forming apparatus according to claim 1, wherein the luminance signal is a signal obtained by sampling a luminance signal separated from an input analog image signal and converting the luminance signal into a digital luminance signal. apparatus. 4. The image forming apparatus according to claim 1, wherein the corrected luminance signal has a larger number of bits than the number of bits of the luminance signal before correction. apparatus. 5. The correction luminance signal is arranged in time series.
4. The image forming apparatus according to claim 1, wherein the image forming apparatus has a luminance signal before correction and a correction portion equal to or less than the number of data bits of the luminance data before correction. 5. . 6. The image forming apparatus according to claim 1, wherein the cold cathode device is a surface conduction type emission device. 7. The device according to claim 1, wherein said cold cathode device is an FE type emission device.
An image forming apparatus according to any one of the preceding claims. 8. The image forming apparatus according to claim 1, wherein said cold cathode device is an MIM type emission device. 9. A multi-electron source in which a plurality of electron-emitting devices are arranged in a matrix using row wirings and column wirings, and an electron beam emitted from the electron-emitting device at a position facing the multi-electron source. An image forming member that forms an image by being scanned, a scanning unit that scans and drives a group of electron-emitting devices connected to the row wiring, and an electron emission existing on a row to be scanned and driven by the scanning unit. Input means for inputting an image signal to be formed by the element group; storing correction data corresponding to the element efficiency of each element of the electron-emitting element group on the row; and inputting the image signal based on the correction data. First correcting means for correcting the following; a modulating means for generating a pulse width modulation signal unique to each electron-emitting device on the row based on the image signal corrected by the first correcting means; Electron emission A second correction unit that includes correction data according to the element efficiency of each element of the element group and generates a current unique to each element on the row; and a logic level of a pulse width modulation signal generated by the modulation unit. An image forming apparatus comprising: a switch unit for applying a current generated by the second correction unit to each of the electron-emitting devices. 10. The image forming apparatus according to claim 9, wherein said electron-emitting device is a cold cathode device. 11. The image forming apparatus according to claim 10, wherein said cold cathode device is a surface conduction electron-emitting device. 12. The image forming apparatus according to claim 10, wherein said cold cathode device is an FE type emission device. 13. The image forming apparatus according to claim 10, wherein said cold cathode device is a MIM type emission device. 14. The image forming apparatus according to claim 9, wherein the input unit includes a unit that converts an analog image signal into a digital image signal. 15. The apparatus according to claim 1, wherein the first correction unit allocates a larger number of bits than the number of bits representing the digital signal converted by the input unit, and generates a corrected digital image signal. Item 15. The image forming apparatus according to Item 14. 16. The first correction unit is a correction process for setting an electron emission period for forming a required brightness point on the image forming member, and the second correction unit is The image forming apparatus according to any one of claims 9 to 15, wherein the correction is processing for flowing a current required for the focused electron-emitting device.