JPH11194740A - Image forming device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To vary the sharpness of an image by varying the size of light emission points while simplifying a circuit by providing a means which discriminates the spatial frequency of an input image and a means which varies the pixel formation size of an image formation part according to the frequency of the input image. SOLUTION: The frequency of the input image is discriminated to display a sharp image when the frequency is high and a soft image when low. Namely, when a frequency discriminator 2 judges that the frequency is high, a switching signal s2 turns ON and a Va switch 7 raises the acceleration voltage (Va) of an electron beam. Consequently, the light emission point size becomes small and the image becomes sharp. When the frequency discriminator 2 judges that the frequency is low, the switching signal s2 turns off and the Va switch 7 lower the Va. Consequently, the light emission point size increases and the image becomes soft. Here, the pulse width is made short when the Va is high and long when low to correct the difference in luminance.

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 and a method of controlling the same, and more particularly, to an image forming apparatus having a plurality of electron emitting portions arranged in a matrix and an image forming portion provided at a position facing the electron emitting portions and the same. It relates to a control method.

[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, and 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. A current is applied by applying a DC voltage to locally destroy, deform, or alter the conductive thin film 3004, and the electron emitting portion 300 in an electrically high resistance state
5 is 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.

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

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). FIG. 1 shows a typical example of an MIM type device configuration.
It is shown in FIG. This figure is a cross-sectional view.
Is a substrate, 3021 is a lower electrode made of metal, 3022 is a thin insulating layer having a thickness of about 100 Å, 302
Reference numeral 3 denotes an upper electrode made of a metal having a thickness of about 80 to 300 angstroms. In the MIM type, the upper electrode 302
By applying an appropriate voltage between the third electrode 301 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)] An example in which a number of MIM types are arranged and applied to an image display device is disclosed in, for example, JP-A-3-55738 by the present applicant.

[0017]

Heretofore, in such a display device, in order to change the sharpness of an image, processing has been performed on a video signal. However, this method requires a complicated signal processing circuit.

[0018]

SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to provide an image forming apparatus which changes the size of a light emitting point and changes the sharpness of an image while simplifying a circuit, and a control method therefor. is there.

In order to solve this problem, for example, the image forming apparatus of the present invention has the following configuration. That is, an image forming apparatus provided with a plurality of electron emitting portions arranged in a matrix and an image forming portion provided at a position facing the plurality of electron emitting portions and receiving an electron beam to form an image. An identification unit for identifying, and a formation size changing unit for changing a pixel formation size in the image forming unit according to a frequency of the input image.

[0020]

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

In this embodiment, a display device capable of displaying two types of images, a sharp image and a soft image, according to the spatial frequency of an input image will be described.

FIG. 1 is a block diagram of an image display device according to the present invention. The signal processing unit 1 separates a synchronization signal and an image signal of the input television signal s1 and performs signal processing such as A / D conversion on the image signal. The A / D converted image data is sent to the serial / parallel converter 3 and the frequency discriminator 2. The serial / parallel converter 3 performs serial / parallel conversion on one line of image data, and sends the data (D1 to Dn) to the pulse width modulator 4.

The frequency discriminator 2 receives image data from the signal processing unit 1. The frequency discriminator 2 discriminates the spatial frequency of the input image and outputs a switching signal s2 for changing the size of the light emitting point. The frequency of the input image is identified using a differentiating circuit or the like. Details will be described later.

The pulse width modulator 4 has image data (D1 to Dn) output from the serial / parallel converter 3.
Is entered. Then, a pulse width modulation signal (analog signal: Dy1 to Dy1) having a pulse length proportional to each data D1 to Dn.
Dyn). In the present embodiment, the case where the gradation expression is represented by pulse width modulation is considered. In other words, the longer the pulse length is, the longer the pixel emits light, and it feels bright.

The Va switch 7 is used to control the acceleration voltage Va of the electron beam.
Is a circuit for switching. Va due to the nature of the emission element
Can be changed to change the beam diameter of the electron beam emitted from the emission element. If Va is large, the beam diameter of the electron beam becomes small, and the light emitting point size becomes small. If Va is small, the beam diameter becomes large and the size of the light emitting point becomes large (the reason will be described later).

The scanning signal generator 5 is a circuit for selecting a scanning row and inputting the scanning signals Dx1 to Dxm to the panel 10.

Next, the operation of this embodiment will be described with reference to FIG.

The received NTSC signal s1 is separated into a synchronizing signal and an image signal by the signal processing unit 1, and the image signal is converted into an A / D signal.
Processing such as conversion is performed. The output digital image data is sent to the serial / parallel converter 3. The serial / parallel converter 3 converts one line of the transmitted image data from serial to parallel, and sends the data (D1 to Dn) to the pulse width modulator 4.

The frequency discriminator 2 receives the image data from the signal processing unit 1, discriminates the frequency of the input image, and outputs a switching signal s2 for changing the size of the light emitting point. FIG. 2 shows a detailed block diagram of the frequency discriminator 2.

The frequency discriminator 2 will be described with reference to FIG. A portion surrounded by a dotted line in FIG. The image data that has been subjected to A / D conversion or the like is first input to the differentiating circuit 100. This differentiation circuit 100
Outputs the difference between adjacent pixel data. The simplest example is to output the difference between the pixel adjacent in the horizontal direction. The circuit at this time is shown in FIG. In this case, the delay circuit 104 is a delay circuit for one pixel (for example, a flip-flop). However, this is one horizontal scanning period (1H)
The difference between the adjacent pixel in the vertical direction or the difference between several adjacent pixels may be obtained by using the delay circuit described above. 1
Numeral 01 denotes an arithmetic notation unit for calculating the absolute value of the difference data output from the differentiating circuit 100. The absolute value of the difference data is input to the integration circuit 102, and the total for one screen (one frame) is output. If the total for one screen is large, it is determined that the spatial frequency of the image is high (an image having a sharp change in luminance), and if the total is small, it is determined that the spatial frequency is low (an image having a gentle luminance change).

This judgment is made by the comparator 103. The comparator 103 outputs an ON signal when the output from the integration circuit 102 is larger than a certain value, and outputs an OFF signal when the output is smaller. This ON / OFF signal is the switching signal s2.

Next, returning to FIG. 1, the operation of the Va switch 7 will be described.

The Va switching unit 7 receives the switching signal s2 and switches the acceleration voltage Va of the electron beam. At this time, there are two types of Va to be switched depending on the magnitude of the voltage value. When s2 is ON, Va is increased and the light emitting point size is reduced. s2
Is OFF, Va is reduced and the light emitting point size is increased. The size of the light emitting point affects the sharpness of the image. If the size of the light emitting point is small, it is easy to pass high frequency components of the image, and if the size of the light emitting point is large, it is difficult to pass high frequency components of the image. Therefore, if the size of the light emitting point is increased, a soft image is obtained, and if the size is reduced, a sharp image is obtained. This is supported by our subjective experiments.

In the present invention, utilizing this fact, the frequency of the input image is identified. When the frequency is high, the image is displayed sharply, and when the frequency is low, a soft image is displayed. When the frequency discriminator 2 determines that the frequency is high, the switching signal s
2 is turned on, and Va is increased by the Va switch 7.
As a result, the size of the light emitting point becomes smaller and the image becomes sharper. Conversely, when the frequency discriminator 2 determines that the frequency is low, the switching signal s2 is turned off, and Va is reduced by the Va switcher 7. As a result, the size of the light emitting point becomes large and the image becomes soft.

However, when Va is changed, the light emission luminance changes as well as the light emission point size. If Va is high, the energy of the accelerating electrons increases and the luminance increases. If Va is low, the energy is low and the brightness is low. At this time,
Brightness is proportional to Va raised to the power of 3/2. In the present invention, two types of pulse widths are used in accordance with Va in order to correct this difference in luminance. When Va is high (when s2 is ON), the pulse width is shortened, and when Va is low (when s2 is OFF).
Is adjusted to increase the pulse width. In the present embodiment, the pulse width gradation is expressed. If the pulse width is long, the pixel feels bright, and if the pulse width is short, the pixel feels dark. At this time, the luminance is proportional to the length of the pulse width. V
The brightness is corrected by shortening the pulse width by increasing a and brightening a, and increasing the pulse width by decreasing Va and decreasing darkness.

Next, the operation of the serial / parallel converter 3 and the pulse width modulator 4 will be described.

The image data that has undergone A / D conversion or the like in the signal processing unit 1 is subjected to serial / parallel conversion of one line of data in the serial / parallel converter 3 (D1 to D1).
n) is input to the pulse width modulator 4. The pulse width modulator 4 outputs a pulse width modulation signal (D
y1 to Dyn). The pulse width modulator 4 outputs a pulse width signal (analog signal: Dy1 to Dyn) having a pulse length proportional to each data (D1 to Dn).

Next, the operation of the pulse width modulator 4 will be described in detail with reference to FIG.

FIG. 3A shows a portion corresponding to the j-th data line of the pulse width modulator. Data k, which has been parallel-converted by the serial / parallel converter 3, is set in the pulse generator 203. When the trigger T1 is input to the pulse generator 203, the output level of the pulse generator 203 becomes high. That is, the pulse width modulation signal Dyj is output. The clock pulse C1 is supplied to the pulse generator 203.
Is always input, and when the number of clock pulses input to the pulse generator 203 after the input of the trigger T1 reaches the set value k, the output (Dyj) becomes low level. The timing chart at this time is as shown in FIG. In this way, a pulse having a width proportional to the input value k is created. Here, if the frequency of the clock pulse C1 supplied to the pulse generator is changed, the width of the pulse output from the pulse generator 203 can be changed even if the same value k is set. That is, the clock pulse C1
When the frequency is increased, the width of the output pulse becomes shorter, and when the frequency is lowered, the pulse width becomes longer. Frequency and output pulse width are inversely proportional.

When the switching signal s2 is ON (when Va is high), the switch 202 shown in FIG.
Output to 3. Since the clock of the clock generator 200 has a high frequency, the output D from the pulse
The pulse width of yj becomes shorter. When the switching signal s2 is OFF (when Va is low), the switch 202 is set to b, and the clock of the clock generator 201 is changed to the pulse generator 2
03 is input. In this case, even if the same signal (k) of Dj is input to the pulse generator 203, the clock frequency of the clock generator 201 is low.
The pulse width of the output Dyj from No. 03 becomes long. In this way, the pulse width is changed between when Va is high and when Va is low,
Returning to FIG. 1 again for correcting the luminance. Scanning signal generator 5
Selects one scan row of the panel 10 and inputs the scan signals Dx1 to Dxm to the selected row. This selected row is 1
The horizontal scanning period (1H) is selected.

Next, the operation of this embodiment will be described with reference to the timing chart of FIG. The symbols in the figure are the same as those in FIG.

Here, suppose that the (n-1) th of the NTSC signal s1 is
It is considered that the spatial frequency of the image is low up to the frame and the frequency of the image is high from the n-th frame. Also, the NTSC signal s1 in the figure represents only 1H signal in each frame.

Now, it is assumed that the frequency discriminator 2 determines that the image data up to the (n-1) th frame has a low spatial frequency and that the image data of the nth frame has a high spatial frequency. At this time, the switching signal s2 is off until the n-th frame. When all the image data of the n-th frame is input, the frequency discriminator determines that the frequency of the image has increased, and
, The switching signal s2 is turned on from the (n + 1) th frame.
become. When the switching signal s2 is turned on, the pulse width modulator 4 switches the clock so that the pulse width becomes short (the switch 202 in FIG. 3A is set to a). As a result, the pulse width becomes shorter. Dyj in FIG. 4 is a signal in one column (the j-th column) in the vertical direction of the panel. The pulse width L is shorter from the (n + 1) th frame. Thereby, the luminance is corrected.

When the switching signal s2 is turned on, Va also becomes larger than the previous voltage value. As a result, the size of the light emitting point is reduced, and the sharpness of the image is increased. Also, Va
The increase in luminance due to the increase in the width is corrected by shortening the pulse width.

Similarly, if it is determined that the spatial frequency has decreased from one frame, Va is decreased from the next frame, and
Increase the emission point size. At the same time, the pulse width is increased for luminance correction.

The scanning signals Dx1 to Dxm are pulse signals having a width of 1H, and are sequentially input for each row of the panel. FIG. 4 shows a scanning signal (Dxi) on the i-th row of the panel.

As described above, by changing the sharpness depending on the light emitting point size without changing the sharpness of the displayed image by the image processing, the conversion of the sharpness can be realized by a simple circuit.

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

FIG. 5 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 this embodiment, the multi electron beam source substrate 1001 is fixed to the rear plate 1005 of the airtight container.
01 has sufficient strength, the substrate 10 of the multi-electron beam source is used as a rear plate of the hermetic container.
01 itself may be used.

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

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

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

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

In order to evacuate the inside of the 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 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, the 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 element structure and manufacturing method of surface conduction type emission element> A typical configuration of a surface conduction type emission element in which an electron emission portion or its peripheral portion is formed of a fine particle film is a flat type or a vertical type. Kinds are given.

<Plane type surface conduction electron-emitting device> First, the structure and manufacturing method of a plane type surface conduction electron-emitting device will be described. FIG. 7 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 1
103, a device electrode; 1104, a conductive thin film; 1105, an electron-emitting portion formed by an energization forming process;
Reference numeral 13 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.

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

Materials that can be used to form the fine particle film include, for example, Pd, Pt, Ru, Ag,
Au, Ti, In, Cu, Cr, Fe, Zn, Sn, T
a, W, Pb, and other metals, PdO, S
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 of FIG. 7, the overlapping manner is such that the substrate, the device electrode, and the conductive thin film are stacked in this order from the bottom, but in some cases, the substrate, the conductive thin film, and the device electrode are stacked in this order from the bottom. I can't wait.

The electron-emitting portion 1105 is a crack-like portion formed in a part of the conductive thin film 1104, and has a higher electrical property 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 element has been described above. In the embodiment, the following element 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].

As a main material of the fine particle film, Pd or P
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 flat surface conduction electron-emitting device. FIGS. 8 (a) to 8 (d)
FIG. 9 is a cross-sectional view for explaining a manufacturing process of the surface conduction electron-emitting device, in which notation of each member is the same as FIG. 7.

1) First, as shown in FIG. 8A, device electrodes 1102 and 1103 are formed on a substrate 1101.

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

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

In the formation, first, an organic metal solution is applied to the substrate (a), dried, heated and baked to form a fine particle film, and 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, 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. 9C, a forming power supply
3, an appropriate voltage is applied, and an energization forming process is performed to form the electron-emitting portion 1105.

The energization forming process 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. 9 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. Also, monitor pulses Pm for monitoring the state of formation of the electron-emitting portion 1105 are inserted at appropriate intervals between the triangular-wave pulses, and the current flowing at that time is measured by the ammeter 1.
It was measured at 111.

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

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

4) Next, as shown in FIG. 8D, an appropriate voltage is applied between the element electrodes 1102 and 1103 from the activating power supply 1112, and the energizing activation process is performed to perform electron emission characteristics. Make improvements.

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

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

FIG. 10A 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. 8D denotes an anode electrode for capturing the emission current Ie emitted from the surface conduction electron-emitting device. The anode electrode 1114 is connected to a DC high-voltage power supply 1115 and an ammeter 1116. (Note that the substrate 1101 is
When the activation process is performed after being incorporated in the display panel, the phosphor screen of the display panel is used as the anode electrode 1114. 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 processing, and the activation power supply 1112 is monitored.
Control the operation of. An example of the emission current Ie measured by the ammeter 1116 is shown in FIG.
When the application of the pulse voltage starts from 12, the emission current Ie increases with the passage of time, but eventually saturates and hardly increases. As described above, when the emission current Ie is substantially saturated, the application of the voltage from the activation power supply 1112 is stopped, and the energization activation process ends.

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

As described above, the plane type surface conduction electron-emitting device shown in FIG. 8E was manufactured.

<Vertical Surface Conduction Emission Device> 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. 11 is a schematic cross-sectional view for explaining the basic structure of the 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 element 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. Accordingly, the above-described element electrode interval L in the planar type shown in FIG. 7 is set as the step height Ls of the step forming member 1206 in the vertical type. Note that for the substrate 1201, the element electrodes 1202 and 1203, and the conductive thin film 1204 using a fine particle film, the materials listed in the description of the planar type can be used in the same manner. For the step forming member 1206, 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. 12A to 12F 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. 12A, 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. 10C, an element electrode 1202 is formed on the insulating layer.

4) Next, as shown in FIG. 11D, 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. 11E, 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, 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 type energization forming process described with reference to FIG. 8C 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. (A process similar to the planar energization activation process described with reference to FIG. 8D may be performed.) As described above, the vertical surface conduction electron-emitting device shown in FIG. Manufactured.

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

FIG. 13 shows typical examples of (emission current Ie) vs. (device applied voltage Vf) characteristics and (device current If) vs. (device applied voltage Vf) characteristics of the devices used in the display device. . Note that the emission current Ie is significantly smaller than the element current If, and it is difficult to show the same current on the same scale.
Since these characteristics are changed by changing design parameters such as the size and shape of the element, the two graphs are shown in arbitrary units.

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

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

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

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

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

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

Further, since the emission luminance can be controlled by using the second characteristic or the third characteristic, 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. 14 is a plan view of the multi-electron beam source used for the display panel of FIG. On the board,
Surface-conduction emission devices similar to those shown in FIG. 7 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 1004
An insulating layer (not shown) is formed between the electrodes at the intersections of the two to maintain electrical insulation.

FIG. 15 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. 16 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, reference numeral 2100 denotes a display panel;
101 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 a CPU, 2107 is an image generation circuit,
2108, 2109 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. (Note that this display device
For example, when receiving a signal including both video information and audio information, such as a television signal, the audio is reproduced at the same time as the display of the video, but the audio information is not directly related to the features of the present invention. Descriptions of circuits, speakers, and the like relating to reception, separation, reproduction, processing, storage, and the like are omitted. Hereinafter, 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.

Further, 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 present 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 generating 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, the computer may be connected to an external computer network via the input / output interface circuit 2105 as described above, and operations such as numerical calculation may be performed in cooperation with an external device.

The input unit 2114 is connected to the CPU 21.
06 is for the user to input commands, programs, data, and the like. For example, in addition to a keyboard and a mouse, a joystick, a barcode reader,
Various input devices such as a voice recognition device can be used.

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 relating 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 section has been described above. With the configuration illustrated in FIG. 16, 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 image memory built in the decoder 2104 and the image generation circuit 21
07 and the CPU 2106 involve not only displaying a selected one of a plurality of pieces of image information but also enlarging, reducing, rotating, moving, edge emphasizing, thinning out, and interpolating the displayed image information. , Color conversion,
It is also possible to perform image processing such as image aspect ratio conversion and the like, and image editing such as combining, erasing, connecting, exchanging, and fitting. Although not specifically mentioned in the description of the present embodiment, a dedicated circuit for processing and editing audio information may be provided as in the above-described image processing and image editing.

Therefore, the present display device is a television broadcast display device, a video conference terminal device, an image editing device that handles still 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. 16 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 of FIG. 16, circuits relating to functions that are not necessary for the intended 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, a display panel using a surface conduction electron-emitting device as an electron beam source can be easily thinned, so that 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.

In the embodiment, an example in which the luminance size and the pulse width modulation are controlled in two steps has been described. However, the number of steps may be three or more, or the user may arbitrarily select. .

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.

[0148]

As described above, according to the present invention, it is possible to change the size of the light emitting point and change the sharpness of the image while simplifying the circuit.

[0149]

[Brief description of the drawings]

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

FIG. 2 is a drive circuit block diagram of the frequency discriminator in FIG.

FIG. 3 is a diagram for explaining the configuration and operation of the pulse width modulator in FIG.

FIG. 4 is a timing chart for explaining the operation of the display device in FIG. 1;

FIG. 5 is a perspective view of the image display device according to the embodiment, in which a part of a display panel is cut away.

FIG. 6 is a plan view illustrating a phosphor array of a face plate of the display panel in the embodiment.

FIG. 7 is a plan view and a cross-sectional view of a planar surface conduction electron-emitting device used in the embodiment.

FIG. 8 is a view showing a manufacturing process of the planar type surface conduction electron-emitting device in the embodiment.

FIG. 9 is a diagram showing an applied voltage waveform during energization forming processing in the embodiment.

FIG. 10 is a diagram showing a change in an applied voltage waveform and a discharge current Ie at the time of the activation process in the embodiment.

FIG. 11 is a sectional view of a vertical surface conduction electron-emitting device according to an embodiment.

FIG. 12 is a diagram illustrating a manufacturing process of the vertical surface conduction electron-emitting device according to the embodiment.

FIG. 13 is a view showing typical characteristics of the surface conduction electron-emitting device used in the embodiment.

FIG. 14 is a plan view of a substrate of the multi-electron beam source used in the embodiment.

FIG. 15 is a partial cross-sectional view of the substrate of the multi-electron beam source used in the embodiment.

FIG. 16 is a block diagram of a display device according to the embodiment.

FIG. 17 is a diagram showing an example of a surface conduction electron-emitting device.

FIG. 18 is a diagram illustrating an example of an FE-type element.

FIG. 19 is a diagram showing an example of the MIM element.

[Explanation of symbols]

 Reference Signs List 1 signal processing unit 2 frequency discriminator 3 serial / parallel converter 4 pulse width modulator 5 scanning signal generator 7 Va switch 10 panel sI NTSC signal s2 switch signal D1 to Dn Modulation data (digital) of each pixel Dy1 to Dyn Pulse width modulation signal of each pixel Dx1 to Dxm Scanning signal of each row 100 Differentiating circuit 101 Circuit for calculating absolute value 102 Integrating circuit 103 Comparator 200, 201 Clock generator 202 Switching switch 203 Pulse generator C1 Clock signal T1 Trigger

Claims (9)

[Claims] 1. An image forming apparatus comprising: a plurality of electron emitting portions arranged in a matrix; and an image forming portion provided at a position facing the plurality of electron emitting portions and receiving an electron beam to form an image. An image forming apparatus comprising: an identification unit that identifies a spatial frequency; and a formation size change unit that changes a pixel formation size in the image forming unit according to a frequency of the input image. 2. The method according to claim 1, wherein the discriminating means calculates a difference between adjacent pixel data, accumulates the absolute value of the difference over one screen, and interlaces a spatial frequency of the image based on the accumulation result. The image forming apparatus according to claim 1. 3. The image forming apparatus according to claim 1, wherein the image forming unit is a display panel having a light emitting body. 4. An electron emission unit comprising a surface conduction electron-emitting device, wherein an electron beam emitted from the surface conduction electron-emitting device is accelerated by an acceleration electrode provided near the image forming unit. The image forming apparatus according to claim 3, wherein the light emitting body is irradiated with the light. 5. The image forming apparatus according to claim 4, wherein the formation size changing unit includes a unit that controls a voltage applied to the acceleration electrode. 6. The image processing apparatus according to claim 5, further comprising: a correction unit that corrects a period of application to the surface conduction electron-emitting unit in accordance with a spatial frequency of the image identified by the identification unit. Item 10. The image forming apparatus according to item 1. 7. The image forming apparatus according to claim 6, wherein said correction means includes means for generating a pulse width modulation signal corresponding to image data. 8. A control method for an image forming apparatus including a plurality of electron emitting portions arranged in a matrix and a display panel provided at a position opposed thereto and having an image forming portion receiving an electron beam and forming an image. An image forming apparatus comprising: an identification step of identifying a spatial frequency of an input image; and a formation size changing step of changing a pixel formation size in the image forming unit according to the frequency of the input image. Control method. 9. An image forming apparatus comprising: a plurality of electron emitting portions arranged in a matrix and an image forming portion provided at a position facing the plurality of electron emitting portions and receiving an electron beam to form an image. An image forming apparatus comprising: an identification unit that identifies a spatial frequency; and an electron beam diameter changing unit that changes a diameter of an electron beam applied to the image forming unit according to a frequency of the input image.