JPH09258687A - Image forming device and method for preventing change of light emitting characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the change of a light emitting characteristic in an image forming device provided with an electron discharging source in which plural cold cathode type electron discharging elements are arranged. SOLUTION: Quantity Ie of discharge current, accurately speaking, the number of electrons reaching a light emitting body such as phosphor is varied and display brightness is varied by variation of vacuum atmosphere of a display device and secular change of a characteristic itself of an electron discharging element. Then, when an image is displayed on an image forming panel 107, difference in brightness is calculated from quantity of electron discharge Iec predicted in design from its image signal in an operation circuit 110 and Ie actually predicted by an Ie detecting circuit 111. Display brightness is compensated by controlling successively an acceleration voltage applying circuit 109 for each line so that the difference is made zero, and changing energy given by electrons discharged from elements when they reaches a light emitting body.

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 provided with an electron emission source in which a plurality of cold cathode type electron emission elements are arranged, and more particularly, an image provided with a stabilizing mechanism for keeping emission luminance stable for a long period of time. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forming device and a method for preventing change in light emission characteristics thereof.

[0002]

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

As the surface conduction type emitting device, for example,
M. I. Elinson, RadioEng. Elec
Tron Phys. , 10, 1290, (1965)
Also, 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)].

FIG. 16 shows a typical example of the device configuration of these surface conduction electron-emitting devices.

FIG. 16 is a plan view of a surface conduction electron-emitting device as a conventional example. Hartwell et al. In the figure, 3001 is a substrate, and 3004 is a conductive thin film made of 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. Interval L in the figure
Is set to 0.5 to 1 [mm], and W is set to 0.1 [mm]. Note that, for convenience of illustration, the electron emission unit 3005
Is shown in a rectangular shape at the center of the conductive thin film 3004,
This is a schematic one, and does not faithfully represent the actual position and shape of the electron emitting portion.

M. In the above-described surface conduction electron-emitting device including the device by Hartwell et al., The electron-emitting portion 300 is formed by performing an energization process called energization forming on the conductive thin film 3004 before the electron emission.
It was common to form 5. That is, the energization forming is performed by applying a constant DC voltage or a DC voltage that is boosted at a very slow rate of, for example, about 1 V / min to both ends of the conductive thin film 3004 to energize the conductive thin film 3004. Of the electron-emitting portion 300 in the electrically high resistance state by locally destroying, deforming, or degrading
5 is to be formed. Note that a crack is generated in a part of the conductive thin film 3004 that is locally broken, deformed, or altered. After the energization forming, the conductive thin film 3
When an appropriate voltage is applied to 004, electrons are emitted near the crack.

An example of the FE type is disclosed in, for example, W.S. P. D
yke & W. W. Dolan, "Field emis
zone ", Advance in Electron
Physics, 8, 89 (1956) or C.I. A. Spindt, "Physical p
rightsies of thin-film fi
eld emissioncathodes with
molybdenium cones ", J. App.
l. Phys. , 47, 5248 (1976).

FIG. 17 shows a typical example of the FE type element structure.

FIG. 17 is a cross-sectional view of an FE type emission element as a conventional example. A. This is due to Spindt et al.

In the figure, 3010 is a substrate, 3011 is an emitter wire 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, as shown in FIG.
There is also an example in which the emitter and the gate electrode are arranged on the substrate substantially parallel to the substrate plane, instead of the laminated structure as in 7.

As an example of the MIM type, for example,
C. A. Mead, “Operation of tu
nnel-emission Devices, J. et al. A
ppl. Phys. , 32,646 (1961) and the like are known. FIG. 18 shows a typical example of the MIM type device configuration.
Shown in

FIG. 18 is a sectional view of a conventional MIM type emission element.

In the figure, 3020 is a substrate, 3021 is a lower electrode made of metal, 3022 is a thin insulating layer having a thickness of about 100 angstroms, and 3023 is an upper electrode made of metal having a thickness of about 80 to 300 angstroms. In the MIM type, electrons are emitted from the surface of the upper electrode 3023 by applying an appropriate voltage between the upper electrode 3023 and the lower electrode 3021.

The cold cathode device described above can obtain electron emission 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. Further, even if a large number of elements are arranged on the substrate at a high density, problems such as heat melting of the substrate hardly occur. In addition, the response speed is slow because the hot cathode element operates by heating the heater,
In the case of a cold cathode device, there is also an advantage that the response speed is high. Therefore, research for applying the cold cathode device has been actively conducted.

For example, the surface conduction electron-emitting device has an advantage that a large number of devices can be formed over a large area because it has a particularly simple structure and is easy to manufacture among cold cathode devices. Therefore, for example, Japanese Patent Application Laid-Open No.
Methods for arranging and driving a large number of devices have been investigated, as disclosed at 32.

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

Particularly, as an application to an image forming apparatus, as disclosed in, for example, USP 5,066,883 by the present applicant, JP-A-2-257551 and JP-A-4-28137, a surface conduction electron-emitting device is used. An image forming apparatus using a combination of a phosphor that emits light when irradiated with an electron beam has been studied. The image forming apparatus in which the surface conduction electron-emitting device and the phosphor are combined is expected to have better characteristics than other conventional image forming apparatuses. For example, compared to a liquid crystal display device that has become widespread in recent years, it can be said that it is excellent in that it is a self-luminous type and does not require a backlight and has a wide viewing angle.

A method of driving a plurality of FE types arranged side by side is disclosed in, for example, USP 4,904,895 by the present applicant. Further, as an example in which the FE type is applied to an image forming apparatus, for example, R.I. The flat panel display reported by Meyer et al. Is known. [R. Meye
r: "Recent Development on
Microtips Display at LET
I ", Tech. Digest of 4th In
t. Vacuum Microele-troni
cs Conf. , Nagahama, pp .; 6-9
(1991)] Further, as an example in which a large number of MIM types are arranged and applied to an image forming apparatus, for example, Japanese Patent Application Laid-Open No. 3-55738 by the present applicant.
Is disclosed.

[0021]

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 an electron emission source in which a large number of cold cathode elements are arranged (hereinafter referred to as a multi-electron beam source) and an image forming apparatus to which the multi-electron beam source is applied.

The inventors of the present invention have, for example, a multi-electron beam source by an electrical wiring method shown in FIG. 19, that is, a multi-electron beam in which a large number of cold cathode elements are arranged two-dimensionally and these elements are wired in a matrix. I have tried the source.

FIG. 19 is a diagram for explaining a conventional multi-electron beam source in which a plurality of surface conduction electron-emitting devices are arranged.

In the drawing, 4001 schematically shows a cold cathode device. Reference numeral 4002 is a row-direction wiring, and 4003 is a column-direction wiring. Row direction wiring 4002 and column direction wiring 4
003 actually has a finite electrical resistance, but is shown as wiring resistances 4004 and 4005 in the figure. The above-described wiring method is called simple matrix wiring. Although a 6 × 6 matrix is shown for convenience of illustration, the scale of the matrix is not limited to this. For example, in the case of a multi-electron beam source for an image forming apparatus, desired image display is performed. This is to arrange and wire the elements that are sufficient. In a multi-electron beam source in which elements are arranged in a simple matrix, appropriate electric signals are applied to the row-direction wiring 4002 and the column-direction wiring 4003 in order to output a desired electron beam. For example,
To drive the cold cathode device in any one row in the matrix, the selection voltage Vs is applied to the row-direction wiring 4002 of the selected row, and at the same time, the row-direction wiring 400 of the non-selected row.
2, a non-selection voltage Vns is applied. In synchronization with this, a drive voltage Ve for outputting an electron beam is applied to the column wiring 4003. According to this method, the wiring resistance 400
Ignoring the voltage drops caused by Nos. 4 and 4005, the voltage of Ve-Vs is applied to the cold cathode element in the selected row, and Ve-Vns is applied to the cold cathode element in the non-selected row.
Is applied. If Ve, Vs, and Vns are set to appropriate voltages, an electron beam with a desired intensity should be output only from the cold cathode element in the selected row.
Further, if different driving voltages Ve are applied to the respective column-direction wirings, electron beams of different intensities should be outputted from the respective elements in the selected row. In addition, the drive voltage Ve
It should be possible to change the length of time for which the electron beam is output by changing the length of time for which is applied. Therefore, the multi-electron beam source in which the cold cathode elements are wired in a simple matrix has various applications. For example, if an electric signal according to image information is appropriately applied, it can be suitably used as an electron source for an image forming apparatus. it can. In various image forming devices that apply electron-emitting devices, including the flat-panel display device described above, it is natural that high-quality, high-definition images and large screens are desired, and their performance is long-term. Need to continue. Since this display method causes a light emission phenomenon using electrons, it is necessary to maintain the atmosphere at a low pressure (vacuum) and keep the atmosphere constant for a long period of time.

However, in the multi-electron beam source in which the cold cathode elements described in the above-mentioned conventional example are wired in a simple matrix, when the atmosphere changes due to a change in gas composition or the like, electron emission characteristics, to be exact, fluorescence. The number of electrons that reach the light-emitting body such as the body fluctuates, resulting in unstable brightness and poor display quality. Therefore, in order to keep the atmosphere constant for a long period of time, a very advanced manufacturing technique is required, and there has been a problem that it is difficult to reduce the product cost.

Therefore, the present invention is an image forming apparatus provided with an electron emission source in which a plurality of cold cathode type electron emitting elements are arranged, and an image forming apparatus capable of preventing a change in light emission characteristic and its light emission characteristic. The purpose is to provide a change prevention method.

[0027]

In order to achieve the above-mentioned object,
The image forming apparatus of the present invention has the following features.

That is, only the electron emission source in which a plurality of cold cathode type electron emission elements are arranged in a matrix and the electron emission element corresponding to a video signal for one scan are selected from the electron emission elements, and the electron emission element is selected. Driving means for driving via row and column wirings connected to each other, accelerating means for accelerating electrons emitted by the electron-emitting device driven by the driving means, and electrons accelerated by the accelerating means. In the image forming apparatus including a light emitting unit that emits light from the phosphor screen, a measuring unit that measures the amount of electrons emitted by the electron-emitting device as an emission current value, and based on the video signal for one scan. And a correction calculation unit that corrects the output of the drive unit and / or the acceleration unit so as to match the theoretical emission current value with the emission current value. It is characterized by having. As a result, the brightness is corrected in real time while performing the normal image display operation.

Specifically, the video signal for one scan is a video signal for one row-direction wiring. Thereby, the structure of the correction circuit is simplified by using the signal used for the normal image display operation.

Further preferably, the drive means has a drive pulse having a pulse width corresponding to the intensity of the video signal, or a voltage corresponding to the intensity of the video signal, and each pulse has a predetermined width. Is generated. This controls the amount of electrons emitted or the energy that the electrons have when reaching the phosphor screen.

Further, when the luminance of the image formed by the light emitting means is displayed by a light emission characteristic that is linear with the emission current, the correction calculation means multiplies the emission current amount by a coefficient to obtain the theoretical emission current value. calculate. Alternatively, when the image forming apparatus gamma-converts the video signal, the theoretical emission current value is calculated according to the gamma curve.

More preferably, the light emitting means forms an image by irradiating the phosphor screen having a plurality of phosphors with electrons emitted from the electron-emitting device via electrodes on a flat plate. To do. In order to achieve the above-mentioned object, the method for preventing change in light emission characteristics of the image forming apparatus of the present invention has the following features.

That is, an electron emission source is formed by arranging a plurality of cold cathode type electron emission elements in a matrix, and only the electron emission elements corresponding to a video signal for one scan are selected from the electron emission elements, and the electron emission elements are selected. A driving process of driving through the row-direction wiring and the column-direction wiring to which the emitting devices are connected, an accelerating process of accelerating the electrons emitted by the electron-emitting devices, and a phosphor screen emitting light by the electrons accelerated in the accelerating process. A method for preventing a change in light emission characteristics in an image forming apparatus for forming an image by further comprising: measuring the amount of electrons emitted by the electron-emitting device as an emission current value to obtain a video signal for one scan. And a correction calculation step of correcting the output of the driving step and / or the accelerating step so that the theoretical emission current value is calculated based on the theoretical emission current value and the emission current value is substantially equal to the theoretical emission current value. Characterized in that was. This allows
Brightness correction is performed in real time while performing normal image display operation.

Specifically, the video signal for one scan is a video signal for one row-direction wiring.
Thereby, the structure of the correction circuit is simplified by using the signal used for the normal image display operation.

In the driving step, a driving pulse having a pulse width corresponding to the intensity of the video signal or a voltage corresponding to the intensity of the video signal is provided, and each pulse has a predetermined width. It is characterized in that a drive pulse is generated. This controls the amount of electrons emitted or the energy that the electrons have when reaching the phosphor screen.

More preferably, when the brightness of the image formed on the phosphor screen is displayed by a light emission characteristic which is linear with the emission current, the theoretical emission current value is multiplied by a factor of the emission current amount in the correction calculation step. calculate. Alternatively, when the video signal is gamma converted, the theoretical emission current value is calculated in the correction calculation step according to the gamma curve.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of convenience, the structure, manufacturing method, and characteristics of the electron-emitting device, the display panel structure of the image forming apparatus, the manufacturing method, and the like, which are suitable for the present invention, will be described in detail later.

[First Embodiment] A drive circuit of an image forming apparatus according to the first embodiment will be described with reference to FIG.

FIG. 1 is a block diagram of a drive circuit of an image forming apparatus as a first embodiment of the present invention.

In the normal image forming operation shown in the figure, first, a decoder 101 inputs a luminance signal (R, R, R) of three primary colors (red, green and blue) to a composite video signal input from an external device.
G, B) and horizontal and vertical sync signals (HSYNC, VSY)
NC). The timing generation circuit 102 generates various timing signals in synchronization with the HSYNC and VSYNC signals. On the other hand, the R, G, B luminance signals are sampled and held at a predetermined timing in the sample hold (S / H) circuit 103. Also,
The held signal is converted into a serial signal in the signal array conversion circuit 104 in the order corresponding to the array of each phosphor (see the electron-emitting device and display panel structure described later, manufacturing method) of the image forming panel 107. Next, a serial / parallel conversion circuit (S / S) for converting this serial signal into an analog signal using a CCD or the like is converted into a parallel signal.
P) The conversion circuit 105 converts into a parallel video signal for each row, that is, for each horizontal row-direction wiring in the image forming panel 107. The parallel video signal for each row is converted into a drive pulse having a pulse width according to the intensity of each video signal in the pulse width modulation circuit (PWM) 106. In the image forming panel 107 supplied with the drive pulse, only the emission element connected to the row selected by the scanning circuit 108 emits electrons for a period corresponding to the width of each pulse included in the supplied drive pulse. discharge.
These electrons are accelerated by the output voltage of the accelerating voltage application circuit 109 and are irradiated to the same position on the face plate (see electron-emitting device and display panel structure described later, manufacturing method), so that the phosphor at that position emits light. To do. Scanning circuit 1
In 08, a two-dimensional image is formed by sequentially scanning selected rows.

Then, the arithmetic circuit 110 for performing the arithmetic operation for correcting the luminance calculates the sum total signal for one row of the serial video signals output from the signal arrangement conversion circuit 104,
Based on the signal, the design emission current value Iec to be obtained at that time is calculated. On the other hand, the emission current (Ie) detection circuit 111, which is a circuit for measuring the electron beam output of the emission element of the image forming panel 107, obtains the actual emission current value output from the emission element. The difference (ΔIe) between the designed emission current value Iec and the actual emission current Ie changes according to the rate of change in luminance due to the change in the emission current value, so the difference (change amount) ΔIe becomes zero. Thus, the output voltage of the acceleration voltage applying circuit 109 is adjusted. As a result, since the emission brightness can be corrected in real time for each row of the emitting elements, the obtained emission brightness is stable even when the electron beam output from each emitting element to the phosphor screen is unstable. As a result, high display quality can be obtained. Although the above description is for PWM, voltage modulation may be used. In that case, 10
The drive circuit 6 generates a voltage pulse (however, each pulse has a predetermined width) according to the intensity of the input video signal.

[Second Embodiment] In the first embodiment,
The change in emission luminance due to the change in emission current value was corrected and stabilized by controlling the acceleration voltage of emitted electrons. In that case, the energy of the emitted electrons is changed, but in the second embodiment, by controlling the drive voltage to each emission element, the emission amount of electrons is changed to stabilize the brightness. To do. A drive circuit of the image forming apparatus of the second embodiment will be described with reference to FIG.

FIG. 2 is a block diagram of a drive circuit of an image forming apparatus as a second embodiment of the present invention.

In a normal image forming operation in the figure, first, a decoder 201 inputs a luminance signal (R, R) of three primary colors (red, green, blue) to a composite video signal input from an external device.
G, B) and horizontal and vertical sync signals (HSYNC, VSY)
NC). The timing generation circuit 202 generates various timing signals in synchronization with the HSYNC and VSYNC signals. On the other hand, the R, G, B luminance signals are sampled and held at a predetermined timing in a sample hold (S / H) circuit 203. Also,
The held signal is converted into a serial signal in the signal array conversion circuit 204 in the order corresponding to the array of each phosphor (see the electron-emitting device and the display panel structure described later, the manufacturing method) of the image forming panel 207. Next, a serial / parallel conversion circuit (S / S) for converting this serial signal into an analog signal using a CCD or the like is converted into a parallel signal.
P) The conversion circuit 205 converts into a parallel video signal for each row, that is, for each horizontal row-direction wiring in the image forming panel 207. The parallel video signal for each row is converted into a drive pulse having a pulse width corresponding to the intensity of each video signal in a pulse width modulation circuit (PWM) 206. In the image forming panel 207 supplied with the drive pulse, only the emission element connected to the row selected by the scanning circuit 208 emits electrons for a period corresponding to the width of each pulse included in the supplied drive pulse. discharge.
These electrons are accelerated by the output voltage of the accelerating voltage application circuit 209 and are irradiated to the same position on the face plate (see electron-emitting device and display panel structure described later, manufacturing method), so that the phosphor at that position emits light. To do. Scanning circuit 2
In 08, a two-dimensional image is formed by sequentially scanning selected rows.

Then, the arithmetic circuit 210 for performing the arithmetic operation for correcting the luminance calculates the total sum signal for one row of the serial video signals output from the signal arrangement conversion circuit 204,
Based on the signal, the design emission current value Iec to be obtained at that time is calculated. On the other hand, the actual emission current value output from the emission element is obtained by the emission current (Ie) detection circuit 211, which is a circuit for measuring the electron beam output of the emission element included in the image forming panel 207. The difference (ΔIe) between the designed emission current value Iec and the actual emission current Ie changes according to the rate of change in luminance due to the change in the emission current value, so the difference (change amount) ΔIe becomes zero. As described above, the output voltage of the element voltage application circuit 212 (corresponding to the drive voltage Ve for outputting the electron beam to the column-direction wiring in FIG. 19) is applied, and by controlling this, the electron emission amount is adjusted. . As a result, since the emission brightness can be corrected in real time for each row of the emitting elements, the obtained emission brightness is stable even when the electron beam output from each emitting element to the phosphor screen is unstable. As a result, high display quality can be obtained.

[Third Embodiment] In the third embodiment,
The correction processing by the acceleration voltage described in the first embodiment described above and the correction processing by the drive voltage described in the second embodiment described above are performed together. A drive circuit of the image forming apparatus in this case will be described with reference to FIG. FIG. 3 is a block diagram of a drive circuit of an image forming apparatus as a third embodiment of the present invention.

In the normal image forming operation shown in the figure, first, a decoder 301 inputs a luminance signal (R, R, R) of three primary colors (red, green and blue) to a composite video signal input from an external device.
G, B) and horizontal and vertical sync signals (HSYNC, VSY)
NC). The timing generation circuit 302 generates various timing signals in synchronization with the HSYNC and VSYNC signals. On the other hand, the R, G, B luminance signals are sampled and held at a predetermined timing in a sample hold (S / H) circuit 303. Also,
The held signal is converted into a serial signal in the signal array conversion circuit 304 in the order corresponding to the array of each phosphor (see the electron-emitting device and display panel structure described later, manufacturing method) of the image forming panel 307. Next, a serial / parallel conversion circuit (S / S) for converting this serial signal into an analog signal using a CCD or the like is converted into a parallel signal.
P) The conversion circuit 305 converts into a parallel video signal for each row, that is, for each horizontal row-direction wiring in the image forming panel 307. The parallel video signal for each row is converted into a drive pulse having a pulse width according to the intensity of each video signal in a pulse width modulation circuit (PWM) 306. In the image forming panel 307 supplied with the drive pulse, only the emission element connected to the row selected by the scanning circuit 308 emits electrons for a period corresponding to the width of each pulse included in the supplied drive pulse. discharge.
These electrons are accelerated by the output voltage of the accelerating voltage application circuit 309 and are irradiated to the same position on the face plate (see electron-emitting device and display panel structure described later, manufacturing method), so that the phosphor at that position emits light. To do. Scanning circuit 3
In 08, a two-dimensional image is formed by sequentially scanning selected rows.

Then, the arithmetic circuit 310 for performing the arithmetic operation for correcting the luminance calculates the summation signal for one row of the serial video signals output from the signal arrangement conversion circuit 304,
Based on the signal, the design emission current value Iec to be obtained at that time is calculated. On the other hand, the emission current (Ie) detection circuit 311 that is a circuit for measuring the electron beam output of the emission element of the image forming panel 307 can obtain the actual emission current value output from the emission element. The difference (ΔIe) between the designed emission current value Iec and the actual emission current Ie changes according to the rate of change in luminance due to the change in the emission current value, so the difference (change amount) ΔIe becomes zero. As described above, the output voltage of the accelerating voltage application circuit 309 and the output voltage of the element voltage application circuit 312 (the drive voltage Ve for outputting the electron beam to the column direction wiring in FIG.
Is applied to control this. As a result, since the emission brightness can be corrected in real time for each row of the emitting elements, the obtained emission brightness is stable even when the electron beam output from each emitting element to the phosphor screen is unstable. As a result, high display quality can be obtained.

In the above three embodiments, the designed electron emission amount, that is, the emission current amount I is calculated from the image signal.
As a method of calculating ec, for example, if the luminance of the display image is displayed with a linear emission characteristic with respect to the image signal, the electron emission amount of the emitting element may be controlled so as to be linear with the image signal. In that case, the amount of emitted electrons can be calculated by multiplying the image signal by a coefficient. When performing gamma conversion on an image signal, the amount of emitted electrons may be determined according to the gamma curve.

The arithmetic circuits (110, 210, 31)
0), the serial video signal, which is the basis for calculating the summation signal for one row of the video signal, is converted into a signal array conversion circuit (104, 20).
4, 304), the S / H circuit (103, 20)
It goes without saying that the summed signals for one row of the video signal may be calculated by directly inputting the signals for each pixel output from (3, 303) to the arithmetic circuit.

<Structure and Manufacturing Method of Display Panel> First,
The configuration and manufacturing method of the display panel of the image forming apparatus to which the present invention is applied will be described with reference to specific examples.

FIG. 4 is a perspective view of a display panel according to an embodiment of the present invention. One of the panels is shown to show the internal structure.
The part is cut away.

In the figure, 1005 is a rear plate, and 1006.
Is a side wall, 1007 is a face plate, 1005
˜1007 form an airtight container for maintaining a vacuum inside the display panel. When assembling an airtight container, it is necessary to seal the joints of each member in order to maintain sufficient strength and airtightness.For example, apply frit glass to the joints, and in the atmosphere or nitrogen atmosphere, Sealing was achieved by firing at 400-500 degrees 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.
Are formed by N × M. Note that 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 intended for high-definition television display, it is desirable to set the numbers N = 3000 and M = 1000 or more. In this embodiment, N = 3072 and M = 1024. The N × M cold cathode elements are arranged in a simple matrix by M row-direction wirings 1003 and N column-direction 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 in detail later.

In this embodiment, the multi-electron beam source substrate 1001 is fixed to the rear plate 1005 of the airtight container, but the multi-electron beam source substrate 10 is fixed.
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.

A fluorescent film 1008 is formed on the lower surface of the face plate 1007. Since the present embodiment is a color image forming apparatus, the fluorescent film 1008 is separately coated with phosphors of three primary colors of red, green and blue used in the field of CRT. This state is shown in FIG.

FIG. 5 is a diagram showing an arrangement of phosphors on a face plate as an embodiment of the present invention.

In the figure, the phosphors of the respective colors are applied in stripes as shown in FIG. 5A, for example, and black conductors 1010 are provided between the stripes of the phosphors. The purpose of providing the black conductor 1010 is to prevent the display color from being displaced even if the irradiation position of the electron beam is slightly displaced, and to prevent the reflection of external light to prevent the display contrast from being lowered. This is to prevent the fluorescent film from being charged up by the electron beam. Although graphite was used as the main component for the black conductor 1010, other materials may be used as long as they are suitable for the above purpose. In addition, the method of separately coating the phosphors of the three primary colors is as shown in FIG.
The arrangement is not limited to the stripe arrangement shown in FIG. 5A, but may be a delta arrangement as shown in FIG. 5B, or any other arrangement.

In the case of producing a monochrome display panel, a monochromatic phosphor material may be used for the phosphor film 1008, and a black conductive material may not necessarily be used.

On the surface of the fluorescent film 1008 on the rear plate side, a metal back 1009 known in the field of CRT is used.
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 is to be protected, to act as an electrode for applying an electron beam accelerating voltage, and to act as a conductive path for excited electrons in 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.
The metal back 1009 is not used when a low voltage phosphor material is used for the phosphor film 1008.

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

Further, Dx1 to Dxm and Dy1 to Dyn and Hv
Is an electric connection terminal of an airtight structure provided for electrically connecting the display panel and an electric circuit (not shown).
Dx1 to Dxm are row-direction wirings 1003 of the multi-electron beam source
And Dy1 to Dyn are the wiring 10 in the column direction of the multi-electron beam source.
04 and Hv are metal back 100 of face plate
9 is electrically connected.

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

The basic structure and manufacturing method of the display panel of the embodiment of the present invention have been described above. The multi-electron beam source used in the image forming apparatus of the present invention is not limited in the material, shape or manufacturing method of the cold cathode element as long as it is an electron emission source in which the cold cathode elements are wired in a simple matrix. Therefore, for example, a surface conduction electron-emitting device, an FE type, or a MIM type cold cathode device can be used. However, under the circumstances where an image forming apparatus having a large display screen and being inexpensive is required, among these cold cathode devices, the surface conduction electron-emitting device is particularly desirable. 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. Further, in the MIM type, it is necessary to make the thicknesses of the insulating layer and the upper electrode thinner 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, among the surface conduction electron-emitting devices, the inventors of the present application
It has been found that the electron-emitting portion or its peripheral portion formed of a fine particle film has 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 an image forming apparatus having high brightness and a large screen. 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 wired in a simple matrix will be described.

<Preferable Device Structure and Manufacturing Method of Surface Conduction Type Emitting Element> Typical structures of the surface conduction type emitting device in which the electron emitting portion or its peripheral portion is formed of a fine particle film include a planar type and a vertical type. There are two types.

(Plane Type Surface Conduction Type Emitting Element) First, the element structure and manufacturing method of the plane type surface conduction type emitting element will be described.

FIG. 6 is a plan view and a sectional view of a surface conduction electron-emitting device as an embodiment of the present invention.

In the figure, 1101 is a substrate, 1102 and 110.
Reference numeral 3 denotes an element electrode; 1104, a conductive thin film; 1105, an electron-emitting portion formed by an energization forming process;
Is a thin film formed by energization activation treatment.

As the substrate 1101, for example, various glass substrates such as quartz glass and soda lime glass, various ceramics substrates such as alumina, or an insulating layer made of, for example, SiO 2 is laminated on the above various substrates. Substrate, etc. can be used.

Further, the device electrodes 1102 and 1103 provided on the substrate 1101 so as to face each other in parallel to the substrate surface are made of a conductive material. For example, N
i, Cr, Au, Mo, W, Pt, Ti, Cu, Pd,
Materials such as Ag and the like, alloys of these metals, metal oxides such as In2 O3 --SnO2, semiconductors such as polysilicon, and the like may be appropriately selected and used. The electrodes can be easily formed by combining a film forming technique such as vacuum deposition and a patterning technique such as photolithography and etching, but it can be formed by another method (for example, a printing technique). It doesn't matter.

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 interval L is designed by selecting an appropriate value from the range of several hundreds angstroms to several hundreds of micrometers, but it is preferable that the electrode spacing L is more than several micrometers for application to an image forming apparatus. It is in the range of several tens of micrometers. Further, the thickness d of the device electrode is usually selected from an appropriate value within the range of several hundred angstroms to several micrometers.

Further, a fine particle film is used for the portion of 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 particles are spaced apart, a structure in which the particles are adjacent to each other, or a structure in which the 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 1102
Alternatively, the conditions necessary for making good electrical connection with 1103, the conditions necessary for favorably performing the energization forming described below, the conditions necessary for setting the electric resistance of the fine particle film itself to an appropriate value described below, Etc.

Specifically, it is set within the range of several angstroms to several thousand angstroms, but the range of 10 angstroms to 500 angstroms is particularly preferable.

Materials that can be used to form the fine particle film include, for example, Pd, Pt, Ru, Ag, and A.
u, Ti, In, Cu, Cr, Fe, Zn, Sn, T
Metals such as a, W, Pb, etc., PdO, Sn
O2, In2 O3, PbO, Sb2 O3, and other oxides, HfB2, ZrB2, LaB6, CeB
Borides such as 6, YB4, GdB4, etc., T
Carbides such as iC, ZrC, HfC, TaC, SiC, WC, etc., nitrides such as TiN, ZrN, HfN, etc., semiconductors such as Si, Ge, etc., carbon, etc. And can be appropriately selected from these.

As described above, the conductive thin film 1104 is formed of a fine particle film, and its sheet resistance value is
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 110
Since it is desirable that 2 and 1103 be electrically connected well, they have a structure in which some of them overlap each other. In the example of FIG. 6, the overlapping manner is as follows. From the bottom, the substrate, the device electrode, and the conductive thin film are laminated in this order.
In some cases, the substrate, the conductive thin film, and the device electrode may be stacked in this order from the bottom.

Further, the electron emitting portion 1105 is a crack-like portion formed in a part of the conductive thin film 1104, and has an electrically higher 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 diameter of several angstroms to several hundred angstroms may be arranged in the cracks. 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 single crystal graphite, polycrystalline graphite, amorphous carbon, or a mixture thereof, and the film thickness is 500 [angstrom] or less, but 300 [angstrom] or less. Is more preferable.

Since it is difficult to accurately illustrate 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 1113
The device in which a part of is removed is shown.

The basic structure of a preferable element has been described above, but the following elements are used in the embodiment.

That is, soda lime glass was used for the substrate 1101, and Ni thin films were 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
The thickness of the fine particle film was about 100 [angstrom] and the width W was 100 [micrometer] using dO.

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

FIG. 7 is a cross-sectional view for explaining a manufacturing process of a flat surface conduction electron-emitting device as an embodiment of the present invention.

In the figure, (a) to (d) show respective manufacturing steps of the surface conduction electron-emitting device, and the reference numerals of the respective members are the same as those in FIG.

1) First, as shown in FIG. 7A, device electrodes 1102 and 1103 are formed on a substrate 1101.

Before forming, the substrate 1 is formed.
After sufficiently washing 101 with a detergent, pure water and an organic solvent,
The material of the device electrode is deposited. (As a method for depositing, 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 using photolithography / etching technology,
A pair of device electrodes (1102 and 1103) shown in (a).
To form

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

In forming the film, first, the organometallic solution is applied to the substrate (a), dried, and heated and baked to form a fine particle film, which is then patterned into a predetermined shape by photolithography and etching. . 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, Pd is used as the main element in the present embodiment. Further, although the dipping method is used as the coating method in the embodiment, other methods such as a spinner method or a spray method may be used.) Further, as a method for forming a conductive thin film formed of a fine particle film, other than the method of applying the organometallic solution used in the present embodiment, for example, a vacuum vapor deposition method, a sputtering method, a chemical vapor deposition method, or the like is used. Sometimes used.

3) Next, as shown in FIG. 7C, the forming power supply 1110 to the device electrodes 1102 and 110
3, an appropriate voltage is applied, and an energization forming process is performed to form the electron-emitting portion 1105.

The energization forming treatment means that the electroconductive thin film 1104 made of a fine particle film is energized so that a part of the electroconductive thin film 1104 is appropriately destroyed, deformed or altered to change into a structure suitable for electron emission. It is a process that causes it. 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, an electron emitting portion 1105).
In (2), an appropriate crack is formed in the thin film. still,
After formation, the electrical resistance measured between the device electrodes 1102 and 1103 greatly increases as compared to before the electron emission portion 1105 is formed.

In order to explain the energization method in more detail, an example of an appropriate voltage waveform applied from the forming power supply 1110 will be shown.

FIG. 8 is a diagram showing an example of applied voltage waveforms in the energization forming process according to the embodiment of the present invention.

In the figure, when forming a conductive thin film made of a fine particle film, a pulsed voltage is preferable, and in the case of the present embodiment, a triangular pulse having a pulse width T1 as shown in the figure. Was continuously applied at a pulse interval T2. At that time, the peak value Vpf of the triangular wave pulse is
The pressure was increased sequentially. In addition, a monitor pulse Pm for monitoring the state of formation of the electron-emitting portion 1105 was inserted between triangular-wave pulses at appropriate intervals, and the current flowing at that time was measured by an ammeter 1111.

In the present embodiment, for example, in a vacuum atmosphere of about 10 −5 [torr], for example, the pulse width T1 is 1 [millisecond] and the pulse interval T2 is 1.
0 [millisecond], and the peak value Vpf is set to 0.
The voltage was increased by 1 [V]. 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 the stage
The energization related to the forming process has ended.

The above method is a preferable method for the surface conduction electron-emitting device according to the present 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 spacing L is changed. In this case, it is desirable to appropriately change the energization conditions accordingly.

4) Next, as shown in FIG. 7D, an appropriate voltage is applied from the activation power source 1112 between the device electrodes 1102 and 1103 to carry out the energization activation process to emit electrons. Improve characteristics.

The energization activation process is a process of energizing the electron-emitting portion 1105 formed by the energization forming process under appropriate conditions to deposit 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 the member 1113.) Incidentally, by performing the energization activation treatment, the emission current at the same applied voltage is typically compared with that before the activation. Specifically, it can be increased 100 times or more.

Specifically, 10 minus 4th 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.

Next, the energization method will be described in more detail with reference to FIG.

FIG. 9 is a diagram for explaining the applied voltage and the emission current in the energization activation process according to the embodiment of the present invention.

In the figure, (a) is an example of an appropriate voltage waveform applied from the activation power supply 1112, and (b) shows the emission current Ie emitted with the application of the voltage. In the present embodiment, the energization activation process is performed by periodically applying a rectangular wave of a constant voltage. Specifically, the voltage Vac of the rectangular wave is 14 [V], and the pulse width T3 is 1 [mm]. Second] and the pulse interval T4 is 10 [milliseconds]. The above-mentioned energization conditions are preferable conditions for the surface-conduction type electron-emitting device of the present embodiment, and when the design of the surface-conduction type electron-emitting device is changed, it is desirable to appropriately change the conditions accordingly.

Reference numeral 1114 shown in FIG. 7 (d) is an anode electrode for capturing the emission current Ie emitted from the surface conduction electron-emitting device, to which a DC high voltage power supply 1115 and an ammeter 1116 are connected. . (Note that the substrate 1101
When the activation process is performed after the display panel is incorporated into 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 emission current Ie is measured by the ammeter 1116 to monitor the progress of the energization activation process.
12 is controlled. An example of the emission current Ie measured by the ammeter 1116 is shown in FIG.
When the application of the pulse voltage is started from 112, the emission current Ie increases with the elapse of time, but it eventually saturates and hardly increases. As described above, when the emission current Ie is almost saturated, the voltage application from the activation power supply 1112 is stopped, and the energization activation process is ended.

The above energization conditions are preferable conditions for the surface conduction electron-emitting device of this embodiment, and when the design of the surface conduction electron emission device is changed, the conditions should be changed accordingly. desirable. As described above, the flat surface conduction electron-emitting device shown in FIG. 7E was manufactured.

(Vertical type surface conduction type emission device) Next, another typical structure of the surface conduction type emission device in which the electron emission portion or its periphery is formed of a fine particle film, that is, vertical type surface conduction type emission device. The configuration of the element will be described.

FIG. 10 is a sectional view of a vertical surface conduction electron-emitting device as an embodiment of the present invention.

In the figure, reference numeral 1201 designates substrates 1202 and 120.
3 is an element electrode, 1206 is a step forming member, 1204 is a conductive thin film using a fine particle film, 1205 is an electron emitting portion formed by an energization forming process, and 1213 is a thin film formed by an energization activation process.

The vertical type is different from the above-described flat type in that one of the element electrodes (1202) is provided on the step forming member 1206, and the conductive thin film 1204 covers the side surface of the step forming member 1206. The point is that they are covered. Therefore, the element electrode interval L in the planar type shown in FIG. 6 is set as the step height Ls of the step forming member 1206 in the vertical type. The substrate 1201, the device electrodes 1202 and 1
For 203 and the conductive thin film 1204 using a fine particle film, the materials listed in the description of the planar type can be similarly used. The step forming member 1206 is made of an electrically insulating material such as SiO2.

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

FIG. 11 is a cross-sectional view for explaining a manufacturing process of a vertical type surface conduction electron-emitting device as an embodiment of the present invention.

In the figure, (a) to (f) show respective manufacturing steps of the surface conduction electron-emitting device, and the reference numerals of the respective members are shown in FIG.
Is the same as

1) First, as shown in FIG. 11A, a device electrode 1203 is formed on a substrate 1201.

2) Next, as shown in FIG. 11B, an insulating layer for forming the step forming member is laminated. The insulating layer may be formed by laminating, for example, SiO2 by a sputtering method.
For example, another film forming method such as a vacuum vapor deposition method or a printing method may be used.

3) Next, as shown in FIG. 13C, the device 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 device electrode 1203.

5) Next, as shown in FIG. 7E, a conductive thin film 1204 using a fine particle film is formed. For formation, a film forming technique such as a coating method may be used as in the case of the flat type.

6) Next, as in the case of the flat type, an energization forming process is performed to form an electron emitting portion.
(The same process as the planar energization forming process described with reference to FIG. 7C may be performed.) 7) Next, as in the case of the planar type, energization activation process is performed to emit electrons. Carbon or a carbon compound is deposited near the portion. (The same process as the planar energization activation process described with reference to FIG. 7D may be performed.) As described above, the vertical surface conduction electron-emitting device shown in FIG. 11F. Was manufactured.

Next, the characteristics of the elements used in the image forming apparatus will be described.

<Characteristics of Surface Conduction Type Emitting Element Used in Image Forming Apparatus> FIG. 12 is a diagram showing characteristics of the surface conduction type emitting element according to the embodiment of the present invention.

This figure shows typical examples of (emission current Ie) vs. (device applied voltage Vf) characteristics and (device current If) vs. (device applied voltage Vf) characteristics. The emission current I
Since e is much smaller than the device current If, it is difficult to illustrate it on the same scale, and these characteristics are changed by changing design parameters such as the size and shape of the device. The graphs of the books are shown in arbitrary units.

The element used in the image forming apparatus is the emission current I
e has the following three characteristics.

(1) A certain voltage (this is the threshold voltage Vt
(referred to as h) above, the emission current Ie rapidly increases when a voltage larger than the threshold voltage Vt is applied to the device.
At a voltage below h, the emission current Ie is hardly detected. That is, it is a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie.

(2) Since the emission current Ie changes depending on the voltage Vf applied to the device, the emission current Ie at the voltage Vf.
The magnitude of e can be controlled.

(3) Since the response speed of the current Ie emitted from the element is fast with respect to the voltage Vf applied to the element, the charge amount of the electrons emitted from the element is controlled by the length of time the voltage Vf is applied. it can.

Due to the above-mentioned characteristics, the surface conduction electron-emitting device could be preferably used in the forming apparatus. For example, in the image forming apparatus in which a large number of elements are provided corresponding to the pixels of the display screen, by using the characteristic (1), it is possible to sequentially scan and display the display screen. That is, the threshold voltage V
A voltage equal to or higher than th is appropriately applied, and a voltage lower than the threshold voltage Vth is applied to the non-selected element. By sequentially switching the elements to be driven, the display screen can be sequentially scanned and displayed. Further, since the emission brightness can be controlled by using the characteristic (2) or the characteristic (3), it is possible to perform a gradation display.

<Structure of multi-electron beam source in which a large number of elements are wired in a simple matrix> Next, the structure of a multi-electron beam source in which the above surface conduction electron-emitting devices are arranged on a substrate and wired in a simple matrix will be described.

FIG. 13 is a plan view of the substrate of the multi-electron beam source according to the embodiment of the present invention.

The figure is a plan view of a multi-electron beam source used in the display panel of FIG. In the figure, on the substrate
The surface conduction electron-emitting devices similar to those shown in 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 10
An insulating layer (not shown) is formed between the electrodes at the intersection of 04 to maintain electrical insulation.

FIG. 14 is a sectional view of the substrate of the multi electron beam source according to the embodiment of the present invention, which is taken along line A- of FIG.
An A ′ cross section is shown.

The multi-electron emission source having such a structure is prepared by previously forming the row-direction wiring electrodes 1003, the column-direction wiring electrodes 1004, the inter-electrode insulating layer (not shown), and the device electrodes of the surface conduction electron-emitting device on the substrate. After forming a conductive thin film, the row-direction wiring electrode 1003 and the column-direction wiring electrode 100
The device was manufactured by supplying current to each element via the device 4 and performing a current forming process and a current activation process.

FIG. 15 is a block diagram of a multifunctional image forming apparatus using the image forming apparatus according to the embodiment of the present invention.

In the figure, 2100 is a display panel and 2 is a display panel.
101 is a display panel drive circuit, 2102 is a display controller, 2103 is a multiplexer,
2104 is a decoder, 2105 is an input / output interface circuit, 2106 is a CPU, 2107 is an image generation circuit,
2108 and 2109 and 2110 are image memory interface circuits, 2111 is an image input interface circuit, 2112 and 2113 are TV signal receiving circuits, 21
Reference numeral 14 denotes an input unit. Incidentally, when the image forming apparatus receives a signal including both video information and audio information such as a television signal, it naturally reproduces audio at the same time as displaying video. Descriptions of circuits, speakers, etc. relating to reception, separation, reproduction, processing, storage, etc. of voice information not directly related to the features will be omitted.

The functions of the respective parts will be described below along the flow of image signals.

First, the TV signal receiving circuit 2113 is a circuit for receiving a TV image signal transmitted using a wireless transmission system such as radio waves or spatial optical communication. The system of the TV signal to be received is not particularly limited, and various systems such as NTSC system, PAL system, SECAM system may be used. Further, a TV signal (for example, a so-called high-definition TV such as the MUSE system) including a larger number of scanning lines than these is suitable for taking advantage of the display panel suitable for a large area and a large number of pixels. It is a signal source. The TV signal received by the TV signal receiving circuit 2113 is output to the decoder 2104.

The TV signal receiving circuit 2112 is a circuit for receiving a TV image signal transmitted using a wire transmission system such as a coaxial cable or an optical fiber. Similar to the TV signal receiving circuit 2113, the TV signal system to be received is not particularly limited, and the TV signal received by this circuit is also output to the decoder 2104.

Further, the image input interface circuit 21
Reference numeral 11 denotes a circuit for capturing an image signal supplied from an image input device such as a TV camera or an image reading scanner, and the captured image signal is output to the decoder 2104.

Further, the image memory interface circuit 2
110 is a video tape recorder (hereinafter abbreviated as VTR)
Is a circuit for capturing the image signal stored in the decoder 2104. The captured image signal is output to the decoder 2104.

Further, the image memory interface circuit 2
Reference numeral 109 denotes a circuit for capturing an image signal stored in the video disk, and the captured image signal is output to the decoder 2104.

Further, the image memory interface circuit 2
Reference numeral 108 denotes a circuit for taking in an image signal from a device that stores still image data, such as a so-called still image disk.
It is output to 04.

Further, the input / output interface circuit 210
Reference numeral 5 is a circuit for connecting the image forming apparatus to an external computer, a computer network, or an output device such as a printer. In addition to inputting / outputting image data, character data, and graphic information, in some cases, it is possible to input / output control signals and numerical data between the CPU 2106 of the image forming apparatus and the outside. is there.

Further, the image generation circuit 2107 is provided with image data, character / graphic information, or a CPU which is externally input via the input / output interface circuit 2105.
A circuit for generating display image data based on the image data and character / graphic information output from 2106.
Inside this circuit, for example, a rewritable memory for accumulating image data and character / graphic information, a read-only memory in which image patterns corresponding to character codes are stored, and a processor for performing image processing Etc. and the circuits necessary for image generation are incorporated. The display image data generated by this circuit is the decoder 21.
However, in some cases, it is also possible to input / output to / from an external computer network or printer via the input / output interface circuit 2105.

Further, the CPU 2106 mainly performs operations related to operation control of the image forming apparatus and generation, selection and editing of a display image. For example, a control signal is output to the multiplexer 2103 to appropriately select or combine image signals to be displayed on the display panel. At that time, a control signal is generated to the display panel controller 2102 according to the image signal to be displayed, and the screen display frequency, the scanning method (for example, the interlace system or the non-interlace system), the number of scanning lines in one screen, etc. The operation of the image forming apparatus is controlled appropriately.

Image data or character / graphic information may be directly output to the image generation circuit 2107, or an external computer or memory may be accessed via the input / output interface circuit 2105 to generate image data or character / figure information. Enter graphic information. It is needless to say that the CPU 2106 may be involved in work for purposes other than this (for example, it may be directly involved in a function of generating or 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 2105, and work such as numerical calculation may be performed in cooperation with an external device.

The input unit 2114 is the CPU 21
A user inputs commands, programs, data, and the like into 06. For example, in addition to a keyboard and a mouse, various input devices such as a joystick, a bar code reader, and a voice recognition device can be used. .

The decoder 2104 is a circuit for inversely converting various image signals input from the image generation circuit 2107 or the TV signal reception circuit 2113 into three primary color signals or luminance signals and I signals and Q signals. . Incidentally, it is desirable that the decoder 2104 has an image memory therein, as indicated by a dotted line in FIG. This is to handle a television signal that requires an image memory for reverse conversion, such as the MUSE method. Further, the provision of the image memory facilitates the display of a still image, or the image generation circuit 2107 and the CPU 21.
This is because in cooperation with 06, there is an advantage that image processing and editing such as image thinning, interpolation, enlargement, reduction, and composition can be easily performed.

The multiplexer 2103 is a CPU
The display image is appropriately selected based on the control signal input from the 2106. That is, the multiplexer 2103
Selects a desired image signal from the inversely converted image signals input from the decoder 2104 and selects the drive circuit 210.
Output to 1. In that case, by switching and selecting an image signal within one screen display time, it is 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. .

The display panel controller 2
Reference numeral 102 denotes a circuit for controlling the operation of the drive circuit 2101 based on a control signal input from the CPU 2106.

First, as a component related to the basic operation of the display panel, for example, a signal for controlling the operation sequence of a display panel drive power source (not shown) is output to the drive circuit 2101. In addition, as a signal relating to the driving method of the display panel, for example, a signal for controlling a screen display frequency and a scanning method (for example, an interlace system or a non-interlace system) is output to the drive circuit 2101. In some cases, the drive circuit 210 outputs control signals relating to image quality adjustment such as brightness, contrast, color tone, and sharpness of a display image.
1 may be output.

The drive circuit 2101 is a circuit for generating a drive signal to be applied to the display panel 2100, and the image signal input from the multiplexer 2103 and the display panel controller 21.
02 operates based on a control signal input from the control unit 02.

Although the functions of the respective parts have been described above, the image information input from various image information sources can be displayed on the display panel 2100 in the present image forming apparatus with the configuration illustrated in FIG. . That is, various image signals such as television broadcasting are transmitted to the decoder 2
After inverse conversion at 104, multiplexer 210
3 is appropriately selected and input to the drive circuit 2101. On the other hand, the display controller 2102 generates a control signal for controlling the operation of the drive circuit 2101 according to the image signal to be displayed. The drive circuit 2101 controls the display panel 2 based on the image signal and the control signal.
100 is applied with a drive signal. Accordingly, an image is displayed on display panel 2100. These series of operations are totally controlled by the CPU 2106.

Further, in the present forming apparatus, the decoder 2
An image memory built in 104 and an image generation circuit 2107
In addition to the display of a selection from a plurality of image information, the involvement of the CPU 2106 and
For image information to display, for example, enlargement, reduction, rotation,
It is also possible to perform image processing such as movement, edge enhancement, thinning, interpolation, color conversion, and aspect ratio conversion of images, and image editing such as combining, erasing, connecting, replacing, and fitting. Further, although not particularly mentioned in the description of the present embodiment, like the image processing and image editing described above,
A dedicated circuit for processing and editing audio information may also be provided.

Therefore, the present image forming apparatus includes a display device for television broadcasting, a terminal device for a video conference, an image editing device for handling still images and moving images, a terminal device for a computer,
It is possible to combine the functions of a word processor and other business terminal devices, game consoles, etc., and it has a very wide range of applications for industrial or consumer use. It is needless to say that the above-described configuration of FIG. 15 is an example of the configuration of an image forming apparatus using a display panel having a surface conduction electron-emitting device as an electron beam source, and is not limited to this. For example, among the constituent elements of FIG. 15, circuits related to unnecessary functions may be omitted depending on the purpose of use. On the contrary, the constituent elements may be added depending on the purpose of use. For example, when the present forming apparatus is applied as a video telephone, it is preferable to add a television camera, a voice microphone, an illuminator, a transmission / reception circuit including a modem, and the like to the components.

In this forming apparatus, the display panel using the surface conduction electron-emitting device as the electron beam source can be easily thinned, so that the depth of the entire image forming apparatus can be reduced. In addition, a display panel that uses a surface-conduction type electron-emitting device as an electron beam source can easily enlarge a screen, has high brightness, and has excellent viewing angle characteristics, so that the image forming apparatus is highly realistic and has a powerful image. Can be displayed with good visibility.

[0156]

As described above, according to the present invention, an image forming apparatus having an electron emission source in which a plurality of cold cathode type electron emission elements are arranged can be prevented from changing its light emission characteristics. It is possible to provide an image forming apparatus and a method for preventing a change in its light emitting characteristic. That is, the fluctuation of the emission current emitted by the emitting element is corrected row by row by controlling the accelerating voltage of the emitted electrons and / or the drive voltage applied to each emitting element to prevent the variation of the luminance. . As a result, high-quality image formation with stable display brightness for a long period of time is realized. Therefore, the present invention can correct a slight change in the vacuum atmosphere and a change with time in the element characteristic itself, and thus the manufacturing cost can be reduced.

[0157]

[Brief description of drawings]

FIG. 1 is a block diagram of a drive circuit of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a drive circuit of an image forming apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a drive circuit of an image forming apparatus as a third embodiment of the present invention.

FIG. 4 is a perspective view of a display panel used in an embodiment of the present invention.

FIG. 5 is a diagram showing a phosphor array of a face plate as an embodiment of the present invention.

FIG. 6 is a plan view and a cross-sectional view of a surface conduction electron-emitting device as an embodiment of the present invention.

FIG. 7 is a cross-sectional view for explaining a manufacturing process of the planar surface conduction electron-emitting device as the embodiment of the present invention.

FIG. 8 is a diagram showing an example of an applied voltage waveform in the energization forming process according to the embodiment of the present invention.

FIG. 9 is a diagram illustrating applied voltage and emission current in the energization activation process according to the embodiment of the present invention.

FIG. 10 is a cross-sectional view of a vertical surface conduction electron-emitting device as an embodiment of the present invention.

FIG. 11 is a cross-sectional view for explaining a manufacturing process of a vertical surface conduction electron-emitting device as an embodiment of the present invention.

FIG. 12 is a diagram showing characteristics of a surface conduction electron-emitting device as an embodiment of the present invention.

FIG. 13 is a plan view of a substrate of a multi-electron beam source as an embodiment of the present invention.

FIG. 14 is a sectional view of a substrate of a multi-electron beam source according to an embodiment of the present invention.

FIG. 15 is a block configuration diagram of a multifunctional image forming apparatus using the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 16 is a plan view of a surface conduction electron-emitting device as a conventional example.

FIG. 17 is a cross-sectional view of a conventional FE type emission element.

FIG. 18 is a cross-sectional view of a MIM type emission element as a conventional example.

FIG. 19 is a diagram illustrating a multi-electron beam source in which a plurality of surface conduction electron-emitting devices are arranged as a conventional example.

[Explanation of symbols]

101, 201, 301 Decoder 102, 202, 302 Timing generation circuit 103, 203, 303 S / H circuit 104, 204, 304 Signal array conversion circuit 105, 205, 305 S / P conversion circuit 106, 206, 306 Pulse width conversion Circuit 107, 207, 307 Image forming panel 108, 208, 308 Scanning circuit 109, 209, 309 Accelerating voltage applying circuit 110, 210, 310 Operation circuit 111, 211, 311 Ie detection circuit 212, 312 Element voltage applying means 1001 Substrate 1002 Surface-conduction type emission device 1003 Row direction wiring 1004 Column direction wiring 1005 Rear plate 1006 Side wall 1007 Face plate 1008 Fluorescent film 1009 Metal back 1010 Black conductor 1101 Substrate 1102, 1103 Element electrode 1 04 conductive thin film 1105 electron emission part 1110 forming power supply 1111 ammeter 1112 activation power supply 1113 thin film 1114 anode electrode 1115 direct current high voltage power supply 1116 ammeter 1201 substrate 1202, 1203 element electrode 1204 conductive thin film 1205 electron emission part 1206 step Forming member 1213 Thin film 2100 Display panel 2101 Drive circuit 2102 Display controller 2103 Multiplexer 2104 Decoder 2105 Input / output interface circuit 2106 CPU 2107 Image generation circuits 2108, 2109 and 2110 Image memory interface circuit 2111 Image input interface circuit 2112, 2113 TV signal receiving circuit 2114 Input unit 3001 Substrate 3004 Conductive thin film 300 Electron emission portion 3010 substrate 3011 emitter wiring 3012 emitter cone 3013 insulating layer 3014 gate electrode 3020 substrate 3021 under the electrode 3022 insulating layer 3023 over electrodes 4001 cold cathode elements 4002 line direction wirings 4003 column wirings 4004 and 4005 wiring resistance

Claims (14)

[Claims] 1. An electron emission source in which a plurality of cold cathode type electron emission elements are arranged in a matrix, and among the electron emission elements, only an electron emission element corresponding to a video signal for one scan is selected, and the electron emission element is selected. Driving means for driving via row and column wirings connected to each other, accelerating means for accelerating electrons emitted by the electron-emitting device driven by the driving means, and electrons accelerated by the accelerating means. In the image forming apparatus including a light emitting unit that emits light from the phosphor screen, a measuring unit that measures the amount of electrons emitted by the electron-emitting device as an emission current value; And a correction calculation unit that corrects the output of the drive unit and / or the acceleration unit so that the theoretical emission current value and the emission current value substantially match. Image forming apparatus, characterized in that the. 2. The video signal for one scan is a video signal for one line in the row direction.
The image forming apparatus as described in the above. 3. The image forming apparatus according to claim 1, wherein the drive unit generates a drive pulse having a pulse width according to the intensity of the video signal. 4. The driving means has a voltage according to the intensity of the video signal, and each driving pulse generates a driving pulse having a predetermined width. The image forming apparatus described. 5. The theoretical calculation current value is obtained by multiplying the amount of emission current by a factor when displaying the brightness of an image formed by the light emission device with a light emission characteristic that is linear with the emission current. The image forming apparatus according to claim 1 or 2, wherein 6. The correction calculation means calculates the theoretical emission current value according to a gamma curve when the image forming apparatus performs gamma conversion on the video signal. The image forming apparatus according to claim 2. 7. The light emitting means forms an image by irradiating the phosphor screen having a plurality of phosphors with electrons emitted from the electron-emitting device through an electrode on a flat plate. The image forming apparatus according to any one of claims 1 to 6. 8. The phosphor according to claim 1, wherein the phosphor has three primary colors of red, green, and blue, and a plurality of the phosphors are arranged in a stripe shape or a triangular shape. Image forming apparatus. 9. An electron emission source is formed by arranging a plurality of cold cathode type electron emission elements in a matrix, and only the electron emission element corresponding to a video signal for one scanning is selected from the electron emission elements, and the electron emission element is selected. A driving process of driving through the row-direction wiring and the column-direction wiring to which the emitting devices are connected, an accelerating process of accelerating the electrons emitted by the electron-emitting devices, and a phosphor screen emitting light by the electrons accelerated in the accelerating process A method for preventing changes in light emission characteristics of an image forming apparatus for forming an image by further comprising: measuring an amount of electrons emitted by the electron-emitting device as an emission current value, and converting the amount of electrons into a video signal for one scan. And a correction calculation step of correcting the output of the driving step and / or the acceleration step so that the theoretical emission current value is calculated based on the theoretical emission current value and the emission current value and the emission current value are substantially equal to each other. A method for preventing changes in light emission characteristics, which is characterized in that 10. The light emission characteristic change preventing method according to claim 9, wherein the video signal for one scan is a video signal for one line in the row direction. 11. The method according to claim 9, wherein in the driving step, a driving pulse having a pulse width corresponding to the intensity of the video signal is generated. 12. The driving pulse having a voltage according to the intensity of the video signal and each driving pulse having a predetermined width is generated in the driving step. A method for preventing a change in the light emission characteristics described. 13. The theoretical emission current value is calculated by multiplying the emission current amount by a coefficient in the correction calculation step when displaying the brightness of the image formed on the phosphor screen with a light emission characteristic that is linear with the emission current. The method for preventing change in light emission characteristics according to claim 9 or 10, characterized in that. 14. When gamma-converting the video signal,
11. The method for preventing change in light emission characteristics according to claim 9, wherein the theoretical emission current value is calculated in the correction calculation step according to the gamma curve.