JPH11194739A - Image display device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display an image in a state optimal to the characteristic to each image by controlling a light emitting area rate to a unit area per one pixel in accordance with the characteristic content of the image to be displayed. SOLUTION: When an image signal is inputted to a precision calculation part 1-1, it calculates precision degree required for the image. Then a luminescent spot area rate control part 1-2 determines the degree of the area rate, based on the calculated precision degree. Moreover, a luminance correction part 1-3 corrects the noteworthy pixels inputted, based on the area rate. A drive circuit 1-4 controls to drive a display panel 1-5 so that the corrected attentinal pixel data are emitted, based on the area rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and an image forming apparatus for displaying an image using primary color display elements arranged in a matrix.

[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 is to form an electron emission portion by energization. For example, a constant DC voltage is applied to both ends of the conductive thin film 3004 or a voltage is increased at a very slow rate of, for example, about 1 V / min. Energize by applying DC voltage,
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 the emitter and the gate electrode are arranged on the substrate almost in parallel with the substrate plane, 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. 30 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]

The present inventor has been studying the construction of a display device using the above-mentioned cold cathode device, particularly a surface conduction type emission device, but it is provided at a position facing the device. It has been found that an area of a phosphor (actually, a phosphor film) irradiated with an electron beam, that is, an image having a different texture depending on the size of the bright spot area is displayed.

[0018]

According to the present invention, the light emission or the formation area ratio per unit area per pixel is controlled in accordance with the characteristics of the image to be displayed, so that the characteristics of each image are optimized. It is an object of the present invention to provide an image display apparatus and an image forming apparatus which can display or form an image.

In order to solve this problem, for example, an image display device of the present invention has the following configuration. That is, an image display device for inputting image data and causing a luminous body to emit light for display, wherein a fineness detecting means for detecting fineness of an image to be displayed, and a fineness level detected by the fineness detecting means Luminous area ratio control means for controlling the luminous area in accordance with the luminous area, and luminance correction means for controlling the luminance of the image data to be displayed, which is controlled by the luminous point area control means and in accordance with the luminous area.

[0020]

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

<Structure and Manufacturing Method of Display Panel> First, the structure and manufacturing method of the display panel of the image display device according to the embodiment will be described with reference to specific examples.

FIG. 16 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. When assembling an airtight container, it is necessary to seal the joints of each member to maintain sufficient strength and airtightness.For example, apply frit glass to the joints, and in air or nitrogen atmosphere, Sealing was achieved by baking at 400 to 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.
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 the present embodiment, the substrate 1001 of the multi-electron beam source 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. 7A, black conductors 1010 are provided in stripes, and black conductors 1010 are provided between the phosphor stripes. 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. 7A, and may be, for example, a delta arrangement as shown in FIG. 17B or another arrangement.

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

A metal back 1009, which is well known in the field of CRTs, 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 the present embodiment, for the purpose of applying an acceleration voltage and 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 of 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 airtight container, after the airtight container is assembled, an exhaust pipe (not shown) and a vacuum pump are connected, and the inside of the airtight container is raised to the power of 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 adsorbing 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 the manufacturing method of the display panel according to the embodiment of the present invention 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 case of the MIM type, it is necessary to make the thicknesses 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 many 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 from 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 surface conduction electron-emitting device will be described. FIG. 18 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 laminated on the various substrates described above. 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,
The material may be appropriately selected from metals such as Ag and the like, alloys of these metals, metal oxides such as In 2 O 3 —SnO 2, and semiconductors such as polysilicon. 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.

More specifically, it is set within a range of several Angstroms to several thousand Angstroms, and a preferable range 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
Oxides such as nO2, In2 O3, PbO, Sb2 O3, etc .; HfB2, ZrB2, LaB6, C
Borides such as eB6, YB4, GdB4, 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 shown in 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 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 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. In addition, in the plan view (a), an element in which a part of the thin film 1113 is removed is illustrated.

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, polycrystal 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.

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

That is, blue 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
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 description will be given of a method of manufacturing a preferred planar type surface conduction electron-emitting device. FIGS. 19 (a) to (d)
Is a cross-sectional view 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. 19A, device electrodes 1102 and 1103 are formed on a substrate 1101.

Before formation, 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. 1A, 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. 3C, 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, and to appropriately break, deform, or alter a part of the conductive thin film 1104 to change into 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. 20 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-described method is a preferable method for the surface conduction electron-emitting device of 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 interval L is changed. In such a case, it is desirable to appropriately change the energization conditions accordingly.

4) Next, as shown in FIG. 19D, 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 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 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. 21A 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 periodically applying a rectangular wave having a constant voltage, but 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. 19D denotes 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. 21B. 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, a planar surface conduction electron-emitting device shown in FIG. 19E was manufactured.

<Vertical Surface Conduction Emitting Element> Next, another typical structure 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. 22 is a schematic cross-sectional view for explaining the basic structure of a vertical type. In FIG.
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
As for No. 4, the materials listed in the description of the flat type can be similarly used. Also, the step forming member 12
For 06, 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. 23A to 23F are cross-sectional views for explaining a manufacturing process, and the notation of each member is the same as FIG.

1) First, as shown in FIG. 23A, an element electrode 1203 is formed on a substrate 1201.

2) Next, as shown in FIG. 7B, 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. 3C, an element electrode 1202 is formed on the insulating layer.

4) Next, as shown in FIG. 4D, 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. 7E, 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 emitting portion.
(A process similar to the planar type energization forming process described with reference to FIG. 19C may be performed.) 7) Next, as in the case of the planar type, the energization activation process is performed, and the electron emission section is performed. Carbon or a carbon compound is deposited in the vicinity. (The same process as the planar energization activation process described with reference to FIG. 19D 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. 24 shows typical examples of (emission current Ie) versus (element applied voltage Vf) characteristics and (element current If) versus (element applied voltage Vf) characteristics of the elements 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 with respect to 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 device is faster than the voltage Vf applied to the device, the amount of charge of the electrons emitted from the device depends on the length of time for applying the voltage Vf. Can control.

Because of the above characteristics, the surface conduction electron-emitting device can 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, by using the second characteristic or the third characteristic, the light emission luminance can be controlled, so that a gradation display can be performed.

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

FIG. 25 is a plan view of the multi-electron beam source used for the display panel of FIG. On the substrate, surface conduction electron-emitting devices similar to those shown in FIG. 18 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. 26 is a sectional view taken along the line AA ′ of FIG.
Shown in

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.

FIG. 27 shows a display panel using the above-described surface conduction electron-emitting device as an electron beam source so that image information provided from various image information sources such as television broadcasting can be displayed. It is a figure for showing an example of the constituted multifunctional display. In the figure, 2
100 is a display panel, 2101 is a display panel driving circuit, 2102 is a display controller, 2103 is a multiplexer, 2104 is a decoder,
2105 is an input / output interface circuit, 2106 is C
PU 2107 is an image generation circuit, 2108 and 210
9 and 2110 are image memory interface circuits,
2111 is an image input interface circuit, 2112 and 2113 are TV signal receiving circuits, and 2114 is an input unit.

(When the present display device receives a signal containing both video information and audio information, such as a television signal, it naturally reproduces the audio simultaneously with the display of the video. Descriptions of circuits, speakers, and the like related to reception, separation, reproduction, processing, storage, and the like of audio information that are not directly related to the features of the present invention are omitted.)
The function of each unit will be described along the flow of the image signal.

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 type of TV signal to be received is not particularly limited,
For example, various systems such as the NTSC system, the PAL system, and the SECAM system may be used. A TV signal (for example, a so-called high-definition TV such as the MUSE system) composed of a larger number of scanning lines is suitable for taking advantage of the display panel suitable for a large area and a large number of pixels. 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 wired transmission system such as a coaxial cable or an optical fiber. As with the TV signal receiving circuit 2113, the type of the TV signal to be received is not particularly limited, and the TV signal received by this circuit is also output to the decoder 2104.

The image input interface circuit 21
Reference numeral 11 denotes a circuit for receiving an image signal supplied from an image input device such as a TV camera or an image reading scanner.
Is output to

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.

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.

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.
04 is output.

The input / output interface circuit 210
Reference numeral 5 denotes a circuit for connecting the present display device to an external computer, a computer network, or an output device such as a printer. In addition to inputting and outputting image data, character data, and graphic information, control signals and numerical data can be input and output between the CPU 2106 included in the display device and the outside in some cases. .

Further, the image generation circuit 2107 is provided with image data, character / graphic information input from the outside via the input / output interface circuit 2105, or a CPU.
A circuit for generating display image data based on the image data and character / graphic information output from 2106.
The circuit includes a rewritable memory for storing, for example, image data and character / graphic information, a read-only memory for storing image patterns corresponding to character codes, and a processor for performing image processing. Circuits necessary for generating an image, such as those described above, are incorporated.
The display image data generated by this circuit is output to the decoder 2104, but may be input / output to an external computer network or a printer via the input / output interface circuit 2105 in some cases.

The CPU 2106 mainly performs operations related to operation control of the display device and generation, selection, and editing of a display image.

For example, a control signal is output to multiplexer 2103, and image signals to be displayed on the display panel are appropriately selected or combined. In this case, a control signal is generated for the display panel controller 2102 in accordance with the image signal to be displayed, and the display frequency, the scanning method (for example, interlaced or non-interlaced), the number of scanning lines on one screen, and the like are displayed. The operation of the device is appropriately controlled.

Further, image data and character / graphic information are directly output to the image generation circuit 2107, or an external computer or memory is accessed via the input / output interface circuit 2105 to access the image data or character / graphic information. Enter graphic information.

The CPU 2106 may, of course, be involved in work for other purposes. For example, it may directly relate to a function of generating and processing information, such as a personal computer or a word processor. Alternatively, it may be connected to an external computer network via the input / output interface circuit 2105 as described above, and work such as numerical calculation may be performed in cooperation with external equipment.

The input unit 2114 is connected to the CPU 2106
The user inputs commands, programs, data, and the like, and various input devices such as a joystick, a barcode reader, and a voice recognition device can be used, for example, in addition to a keyboard and a mouse.

Also, the decoder 2104 has the
And 2113 are circuits for inversely converting various image signals inputted from 2113 into three primary color signals or luminance signals and I and Q signals. It is to be noted that the decoder 2104 desirably includes an image memory therein, as indicated by a dotted line in FIG. This is for handling a television signal that requires an image memory when performing inverse conversion, such as the MUSE method. Further, the provision of the image memory facilitates the display of a still image, or enables image processing and editing including image thinning, interpolation, enlargement, reduction, and synthesis in cooperation with the image generation circuit 2107 and the CPU 2106. This is because there is an advantage that it can be easily performed.

The multiplexer 2103 is connected to the C
A display image is appropriately selected based on a control signal input from the PU 2106. That is, the multiplexer 2103 selects a desired image signal from the inversely converted image signals input from the decoder 2104 and outputs the selected image signal to the drive circuit 2101. 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 signal related to the basic operation of the display panel, for example, a signal for controlling an operation sequence of a drive power source (not shown) for the display panel is output to the drive circuit 2101. Also,
A signal for controlling, for example, a screen display frequency and a scanning method (for example, interlaced or non-interlaced) related to the display panel driving method is output to the driving circuit 2101.

In some cases, a control signal related to image quality adjustment such as brightness, contrast, color tone, and sharpness of a display image may be output to the drive circuit 2101.

The drive circuit 2101 is a circuit for generating a drive signal to be applied to the display panel 2100, and includes an 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.

The function of each unit has been described above. With the configuration illustrated in FIG. 27, in this display device, image information input from various image information sources is displayed on the display panel 2.
100 can be displayed. That is, various image signals including television broadcasting are transmitted to the decoder 21.
After the inverse conversion at 04, the multiplexer 2103
And is input to the driving circuit 2101 as appropriate. 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.

In the present display device, the decoder 2
An image memory built in the image processing circuit 104;
And the involvement of the CPU 2106 not only displays the selected one of the plurality of image information but also enlarges, reduces,
It is also possible to perform image processing such as rotation, movement, edge enhancement, thinning, interpolation, color conversion, image aspect ratio conversion, and image editing such as synthesis, erasure, connection, replacement, and fitting. is there. Although not particularly mentioned in the description of the present embodiment, like image processing and image editing,
A dedicated circuit for processing and editing audio information may also be provided.

Therefore, the present display device is a television broadcast display device, a video conference terminal device, an image editing device for handling still images and moving images, a computer terminal device, an office terminal device such as a word processor,
It can be equipped with the functions of a game machine etc. by one unit, and has a very wide application range for industrial or consumer use.

FIG. 27 shows only an example of the configuration of a display device using a display panel using a surface conduction electron-emitting device as an electron beam source, and it goes without saying that the present invention is not limited to this. No. For example, among the components shown in FIG. 27, circuits relating to functions that are not necessary for the purpose of use may be omitted. Conversely, additional components may be added depending on the purpose of use. For example, when the present display device is applied as a video phone, it is preferable to add a transmission / reception circuit including a television camera, an audio microphone, an illuminator, and a modem to the components.

In the present display device, in particular, since the display panel using the surface conduction electron-emitting device as the electron beam source can be easily made thin, the depth of the entire display device can be reduced. In addition, the display panel using surface conduction electron-emitting devices as the electron beam source can easily enlarge the screen, and has high brightness and excellent viewing angle characteristics. It is possible to display well.

The principle of the electron-emitting device, the configuration and the manufacturing method of the display panel, and the applied embodiments have been described above.

On the other hand, various studies have recently been made on the image quality of such a matrix type image display device. One of the problems is the sharpness and smoothness of the image.

According to the literature ("Recent Display Devices", The Television Society of Japan, 1974), "the intermittent sampling function as in the case of the trinitron tube has a pseudo-correction effect of sharpness".

The inventor conducted a subjective evaluation experiment in order to quantify the preference for sharpness and smoothness of an image.

In the experiment, the luminescent spot area ratio of the matrix type display as shown in FIG. 2 was changed for some original images having different sharpness and smoothness. As a result, the following findings were obtained. -The lower the bright spot area ratio, the higher the sharpness. -The higher the bright spot area ratio, the higher the smoothness. -A display with high sharpness is preferred for an image with many details. -An image rich in smooth color tone change is preferably displayed with high smoothness.

The present embodiment which makes effective use of such characteristics will be described below.

[First Embodiment] First, the outline will be briefly described. In the first embodiment, attention is paid to a region of an appropriate size of an input image signal, and the definition of the region is determined. More specifically, the luminance change in the area is determined based on the magnitude, and the result is expressed, for example, in three stages. That is, it is determined at which stage the pixel of interest in that region is located. Then, when the target pixel is reproduced with, for example, 3 × 3 phosphors, the number of light-emitting phosphors is determined. However, since one input pixel is represented by a 3 × 3 phosphor on the display panel, if the luminance of the input pixel is the same, the total sum of the luminances to emit light is the same.

Description will be made with reference to FIG. FIG. 2 is a configuration diagram of a drive circuit of the image display device according to the first embodiment.

In the figure, a definition calculating unit 1-1 is a circuit for calculating the definition of an image area near a pixel of interest from the image signal value of the target eye. The obtained definition is based on the starting area ratio control unit 1-.
Sent to 2. The bright spot area ratio control unit 1-2 outputs an area to be illuminated in the pixel region as a bright spot area ratio according to the definition. The bright spot area ratio is sent to the drive circuit 1-5 and, at the same time, to the brightness correction unit 1-3. If the pixel values are equal, the luminance correction unit 1-3 calculates the luminance correction amount of the image signal according to the luminance area ratio so as to reproduce the same luminance regardless of the area ratio. This luminance correction amount is sent to the drive circuit 1-4. The drive circuit 1-4 causes a predetermined pixel area of the display panel 1-5 to emit light based on the image signal, the bright spot area ratio, and the luminance correction amount.

This will be described in more detail. FIG. 3 is an example in which the definition calculator 1-1 in FIG. 1 is detailed. In the figure,
The image signal is input to the differentiating circuit 3-1 and the differentiation is calculated. This differential value is input to the absolute value calculation circuit 3-2,
All are converted to positive values. That is, data indicating the degree of the change in luminance is obtained. Next, the averaging circuit 3
-3, and outputs a value averaged in the set range as the definition.

FIG. 4 shows a bright spot area ratio control unit 1-2 in FIG.
FIG. Most simply, it can be realized by the look-up table 4-1 as shown in FIG. FIG. 5 is an example showing the input / output relationship of the lookup table 4-1. In FIG. 5, the definition is output in 8 bits,
The luminescent spot area ratio (value indicating how many of the 3 × 3 pixels emit light) is illustrated as one that can be changed in three stages of 1/9, 4/9, and 9/9.

FIG. 6 is a detailed example of the brightness correction section 1-3 in FIG. Most simply, it can be realized by the look-up table 6-1 as shown in FIG. FIG.
FIG. 6 illustrates a luminance correction table based on a look-up table 6-1 when the three-step bright spot area ratio conversion illustrated in FIG. 5 is performed.

FIG. 8 is a detailed example of the drive circuit 1-4 in FIG.

The sub-pixel writing control circuit 8-2 determines the number of 3 × 3 luminous bodies for the target input pixel according to the luminous point area recognition rate (three levels in the embodiment) from the luminous point area ratio control section 1-2. Is determined.

The sub-pixel writing control circuit 8-2 receives data from the multiplication circuit 8-1 for multiplying the image signal by the image signal calculated by the luminance correction section 1-3 and the luminance correction amount. Is divided by the number of illuminants to emit light, and it is distributed to each drive target position.

Thus, for example, if the luminance of the input image data of interest is, for example, "90" and it is preferable to display the image at the position of the pixel of interest with a high definition,
Drive one of the x3 light emitters. When the definition is low (in the case of a smooth area), all of the 3 × 3 luminous bodies are made to emit light, and when the definition is in the middle, 3 × 3 luminous bodies are emitted.
The light is distributed to the corresponding positions so that four of the three light emitters emit light.

The distribution result is stored in the pixel memory 8-3, and is stored in the line buffer 8-4 (having three lines of memory). Driving is performed.

FIG. 9 shows the conversion of the luminescent spot area ratio in this manner.
FIG. 5 is a diagram illustrating an example of an image that has been subjected to luminance correction. The black part shown in the figure indicates a non-light emitting part. FIG. 3A shows an example of image reproduction in a high-definition area, FIG. 3B shows image reproduction in a medium-definition area, and FIG. Image reproduction. In the drawing, an output result corresponding to a 6 × 6 display area, that is, a 2 × 2 area of the input image is shown.

By driving as described above, the emission area is reduced for an image requiring high definition, and the emission area is increased for an image having a smooth density and luminance distribution. It is possible to display a good image depending on the nature of the image.

In the first embodiment, an example in which the surface conduction electron-emitting device is applied to a display device having a matrix arrangement has been described. However, according to the above idea, the invention is applied to a general display device. However, the present invention is not limited to the surface conduction electron-emitting device. However, when an image is reproduced with a large number of display elements per input pixel, if the display elements cannot be reduced in size, the display elements may become obstructive. Therefore, the present invention is to be applied to an apparatus using a surface conduction electron-emitting device. Is desired.

[Second Embodiment] Next, an example suitable for a surface conduction electron-emitting device will be described as a second embodiment.

That is, an electron beam source in which a plurality of surface conduction electron-emitting devices are arranged on a substrate is disposed so as to correspond to each of the three primary colors of red, green, and blue. Example in which one pixel is formed by arranging phosphors for each color that emits visible light by irradiating an electron beam at each of the positions to be applied, and the present invention is applied to a light emitting panel in which a plurality of the pixels are arranged on a two-dimensional plane. Will be described.

First, the characteristics of the electron beam emitted from the surface conduction electron-emitting device will be described.

FIG. 10 shows that the electrons emitted from the electron-emitting devices 1002 of the display panel 1000 are applied to the face plate 1.
FIG. 7 is a cross-sectional view illustrating a state of 007 colliding with a phosphor.

A phosphor (film) 1008 is applied inside the face plate 1007. The electrode 110
2 and 1103 are connected to a column direction wiring 1004 and a row direction wiring 1003, respectively, and when an element voltage (for example, Vf [V]) of a certain value or more is applied, the electron emitting element 1
Electrons are emitted from the electron-emitting portion 1105 of 002. The electrons emitted in this way are applied to the face plate 100 by the anode voltage (acceleration voltage) Va [V] applied between the face plate 1007 and the electron emission section 1105.
The laser beam is accelerated in seven directions and irradiated on the face plate 1007. At this time, the emitted electrons do not proceed to the position directly above the electron emitting portion 1105 along the central axis 100, but to the electron orbit 1
Go along 01. This electron orbit 101 is
Is a positive polarity, and the element voltage V is such that the electrode 1103 has a negative polarity.
This shows the state when f is applied. in this case,
The distance Lef between the central axis 100 and the landing position of the electrons can be calculated by the following equation.

[0144]

Lf = 2 × K × Lh × SQRT (Vf / Va) (1) where Lh [m] is the emission element 1002 and the phosphor 100
8 is a constant determined by the type and shape of the emission element 1002. “SQRT (A)” indicates the square root of A.

FIG. 11 is a plan view of the face plate shown in FIG. The electron beam emitted from the electron-emitting device 1002 has a spread as shown in FIG. Here, if the width of the luminance distribution is defined by P% of the peak luminance, the width of Xs [m] can be defined in the horizontal direction as shown in the figure. This width can be calculated by the following equation.

[0146]

Xs = Lh × Kxs × SQRT (Vf / Va) + Xoff (2) where Lh [m] is the emission element 1002 and the phosphor 100
8 are constants determined by the type and shape of the emission element 1002.

From the equation (2), it can be seen that if the anode voltage (acceleration voltage) Va is the same, the electron beam width Xs increases as the element voltage Vf increases.

On the other hand, in the present electron-emitting device, if the device voltage Vf changes, the emission current Ie also changes.
Said.

That is, if the element voltage Vf is changed, the size of the luminescent spot can be changed, and the change in emission current accompanying the change can be corrected by, for example, changing the image signal value.

When the present invention is applied to a surface conduction electron-emitting device having such emission characteristics, the basic structure is the same as that shown in FIG. The configuration of the unit and the drive circuit will be described.

Hereinafter, for ease of understanding, a description will be given of a monochrome display panel.

Although the bright spot area ratio control unit shown in FIG. 4 in the first embodiment can be applied to this embodiment, the input / output relationship is set in consideration of the above-described electron emission characteristics. FIG.
9A and 9B show the input / output characteristics of the luminescent spot area control unit in the second embodiment. FIG. 10A shows an example in which the luminescent spot area ratio is steplessly controlled, and FIG. This is an example of a case where the point area ratio is limited to three stages to simplify the circuit. Vf-
max and Vf-min indicate the highest and lowest device voltages at which electrons are properly emitted, and Vf-mid is an example of an intermediate voltage when the voltage is limited to three stages.

Although the brightness correction unit of the second embodiment can also apply the brightness correction unit of FIG. 6 shown in the first embodiment, the input / output relationship is set in consideration of the above-described electron emission characteristics. . FIG. 13 shows the input / output characteristics of the luminance correction unit when applied to a surface conduction electron-emitting device. FIG. 13A shows an example in which the bright spot area ratio is steplessly controlled. FIG. 6B shows an example in which the luminous point area ratio is limited to three stages to simplify the circuit. Vf-max, Vf-mid, V
f-min is the element voltage shown in FIG. 12, and the corresponding correction amounts are Adj-max, Adj-mid, A
dj-min.

FIG. 14 is a detailed example of the drive circuit according to the second embodiment. The luminance correction amount obtained from the luminance correction unit 1-3 in FIG. 1 is multiplied by the image signal by the multiplication circuit 14-1 and sent to the pixel writing control circuit 14-2.
The pixel write control circuit 14-2 uses the output of the multiplication circuit 14-1 and the bright spot area ratio (element drive voltage) obtained from the bright spot area ratio control unit 1-2 in FIG. Write to the corresponding location. This operation is repeated, and when the processing for one scanning line is completed, the line buffer 14-3 completes the processing for one scanning line in this manner.
-3 is sent to the display panel 1-5.

Actually, data on the element voltage and the light emission time for each pixel is stored in the line buffer 14-3.
These element voltages depend on the light emitting area, and the light emitting time is generated by a look-up table corresponding to a function that calculates the input image data, the light emitting area ratio, and the luminance correction amount as arguments. At the time of driving, in order to generate an ON signal for a time corresponding to the light emission time, for example, a pulse width modulation signal is generated, and the element voltage assigned to the pixel is set to the ON time of the generated pulse width signal. Drive with

FIG. 15 is a diagram showing an example of an image which has been subjected to the luminous point area ratio conversion and the luminance correction in this manner. FIG. 3A shows an image reproduction in a high-definition area, and FIG.
Shows an example of image reproduction in a medium definition area, and FIG. 10C shows an example of image reproduction in a low definition, that is, a smooth area.
Note that the drawing shows an example in which the number of input pixels is 2 × 2, and does not mean that 2 × 2 phosphors emit light for one input image.

As described above, according to the second embodiment, by utilizing the specification of the surface conduction electron-emitting device, it is not necessary to relate a plurality of display elements to one input pixel as in the first embodiment. An image can be displayed with one display element for one input pixel (the number of surface conduction electron-emitting devices can be the same as the number of pixels of the input image), and the state of the original image (preferable definition) , The light emitting area can be changed according to the image quality, and good image quality can be obtained.

In the first and second embodiments, the definition is treated in three stages, but is not limited to this. Also,
Although the definition calculation unit, the bright spot area control unit, and the brightness correction unit have been illustrated, the invention is not limited thereto.

Although the display panel has been described in the above embodiment, the present invention may be applied to an apparatus for forming an electrostatic latent image by irradiating an electron beam to form an image. It is not limited.

In the above embodiment, the monochrome display has been described for the sake of simplicity. The present invention can be applied to a color display.

According to the present embodiment as described above,
By changing the light emitting area in accordance with the characteristics of each image such as an image requiring fine detail and an image requiring smoothness, it becomes possible to display a good image suitable for each image.

[0162]

As described above, according to the present invention, the light emission or the formation area ratio per unit area per pixel is controlled in accordance with the characteristics of the image to be displayed, so that the characteristics of each image are optimized. It can be displayed or formed in a proper state.

[0163]

[Brief description of the drawings]

FIG. 1 is a block diagram of a display device according to an embodiment.

FIG. 2 is a diagram showing a bright spot area ratio used for subjective evaluation.

FIG. 3 is a block diagram of a definition calculating unit in FIG. 1;

FIG. 4 is a block diagram of a bright spot area ratio control unit in FIG. 1;

FIG. 5 is a diagram illustrating an input / output relationship of a definition calculation unit.

FIG. 6 is a block diagram of a bright spot correction unit in FIG. 1;

FIG. 7 is a diagram illustrating an input / output relationship of a bright spot correction unit.

FIG. 8 is a diagram showing a drive circuit in FIG. 1;

FIG. 9 is a diagram illustrating an example of a reproduced image according to the first embodiment.

FIG. 10 is a diagram illustrating an electron trajectory emitted from an electron-emitting device.

FIG. 11 is a diagram illustrating a luminance distribution of electrons emitted from the electron-emitting device.

FIG. 12 is a diagram illustrating an input / output relationship of a definition calculator in the second embodiment.

FIG. 13 is a diagram illustrating an input / output relationship of a bright spot correction unit according to the second embodiment.

FIG. 14 is a block diagram of a drive circuit according to a second embodiment.

FIG. 15 is a diagram illustrating an example of a reproduced image according to the second embodiment.

FIG. 16 is a perspective view of the image display device according to the embodiment, in which a part of the display panel is cut away.

FIG. 17 is a plan view illustrating a phosphor array of a face plate of a display panel in the embodiment.

FIG. 18 is a plan view and a cross-sectional view of a planar surface conduction electron-emitting device used in the embodiment.

FIG. 19 is a diagram illustrating a manufacturing process of the flat surface conduction electron-emitting device according to the embodiment.

FIG. 20 is a diagram showing an applied voltage waveform during energization forming processing in the example.

FIG. 21 is a diagram showing changes in an applied voltage waveform and a discharge current Ie during the activation process in the embodiment.

FIG. 22 is a sectional view of a vertical surface conduction electron-emitting device according to an embodiment.

FIG. 23 is a diagram illustrating a manufacturing process of the vertical surface conduction electron-emitting device according to the embodiment.

FIG. 24 is a view showing typical characteristics of the surface conduction electron-emitting device used in the embodiment.

FIG. 25 is a plan view of a substrate of the multi-electron beam source used in the embodiment.

FIG. 26 is a partial cross-sectional view of the substrate of the multi-electron beam source used in the embodiment.

FIG. 27 is a block diagram of a multi-function image display device using the image display device according to the embodiment.

FIG. 28 is a diagram showing an example of a surface conduction electron-emitting device.

FIG. 29 is a diagram illustrating an example of an FE-type element.

FIG. 30 is a diagram illustrating an example of an MIM element.

Claims (9)

[Claims] 1. An image display device for inputting image data and causing a luminous body to emit light for display, comprising: a fineness detection means for detecting the fineness of an image to be displayed; and a fineness detection means for detecting the fineness of the image to be displayed. A bright spot area ratio control means for controlling a light emitting area in accordance with the definition; and a brightness correction means for controlling the brightness of image data to be displayed, which is controlled by the bright spot area control means and in accordance with the light emitting area. An image display device characterized by the above-mentioned. 2. The image display apparatus according to claim 1, wherein the definition detection unit detects information indicating a magnitude of a change in luminance near the position of the pixel of interest as the definition. 3. A method according to claim 1, wherein said bright spot area ratio control means is a means for controlling how many light emitters emit light when a plurality of light emitters are assigned to one input pixel. The image display device according to claim 1. 4. An electron beam source having an electron-emitting device;
What is claimed is: 1. An image display apparatus comprising: a display panel including a luminous body which emits light by receiving electrons flying from said electron beam source, wherein said definition means detects a definition of an image to be displayed; A bright spot area ratio controlling means for controlling a light emitting area by controlling a beam diameter applied to the luminous body in accordance with the definition detected by the detecting means; and a light emitting area controlled by the bright spot area controlling means. An image display device comprising: a luminance correction unit configured to correct luminance of image data to be displayed in accordance with the luminance. 5. The image display device according to claim 4, wherein said electron-emitting device is a surface conduction electron-emitting device. 6. The image display apparatus according to claim 4, wherein the definition detection unit detects information indicating a magnitude of a change in luminance near the position of the target pixel as the definition. 7. The image display device according to claim 4, wherein said electron beam source has a plurality of electron-emitting devices, and said display panel has a plurality of luminous bodies. 8. The image display device according to claim 7, wherein said electron-emitting devices and said luminous bodies are arranged in a matrix. 9. An electron beam source having an electron-emitting device;
An image forming apparatus having an image forming unit configured to form an image by receiving electrons flying from the electron beam source, comprising: a fineness detecting unit configured to detect a fineness of an image to be formed; Area ratio control means for controlling an irradiation area of a beam applied to the image forming unit in accordance with the detected definition; and correcting image data to be formed in accordance with the irradiation area controlled by the area ratio control means. An image forming apparatus comprising: