JP2000242212A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make settable an optimum image according to the kind of an input image signal to be displayed by providing a storage means storing picture quality information related to plural kinds of image signals and a judging means for judging the kind of the input image signal and correcting the input image signal according to the image information corresponding to the judging result of the judging means in the picture quality information stored in the storage means. SOLUTION: A system control part 14 judges automatically the kind of the image signal inputted to a signal switch part based on a synchronizing signal incorporated in the inputted image signal. The signal switch part is provided with a synchronizing separator part 29, a synchronization judging part 30 and a video switch part 31. The system control part 14 judges the input position of the input image signal based on the signal s26 showing the presence of a video signal by the synchronization judging part 30, and judges the kind of an external device by the judged input position. The system control part 14 switches the video signal outputted by the video switch part 31 according to the result of the kind judgement of the external device.

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, for example, an image forming apparatus that forms an image by driving an electron beam source provided with a plurality of electron-emitting devices.

[0002]

2. Description of the Related Art Heretofore, two types of electron-emitting devices, a thermionic electron-emitting device and a cold cathode electron-emitting device, are known. The cold cathode electron emission device includes a field emission type (hereinafter, referred to as “FE type”), a metal / insulating layer / metal type (hereinafter, referred to as “MIM type”), a surface conduction type electron emission device, and the like.

Examples of the surface conduction electron-emitting device include:
M. I. Elinson, Radio Eng. Ele
ctron Pys. , 10, 1290, (1965)
Also, other examples described later are known.

The surface conduction electron-emitting device utilizes a phenomenon in which a thin film having a small area is formed on a substrate and an electric current is caused to flow in parallel with the film surface of the thin film to cause electron emission. Examples of the surface conduction electron-emitting device include a device using an SnO2 thin film by Elinson et al. And a device using an Au thin film [G. Dittmer: "Thin Solid
Films ", 9, 3717 (1972)], In2
O3 / SnO2 thin film [M. Hartwell
and C.I. G. FIG. Fonstad: "IEEE Tran
s. ED Conf. , 519 (1975)], and those based on carbon thin films [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, p. 22, page (1983)] and the like.

[0005] As a typical example of the element structure of these surface conduction electron-emitting devices, FIG. Hartw
1 shows a plan view of an element by ell et al.

In FIG. 1, reference numeral 3001 denotes a substrate.
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 in FIG. An electron emission portion 3005 is formed by applying an energization process called energization forming to be described later to 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.

M. In the surface conduction electron-emitting device described above, including the device by Hartwell et al.
In general, an electron emission portion is formed by performing an energization process called energization forming on the conductive thin film before electron emission. That is, the energization forming is to form an electron emission portion in a part of the conductive thin film by performing a predetermined energization process on the conductive thin film. For example, in FIG. 36, a predetermined DC voltage or a DC voltage which is boosted at a very slow rate of, for example, about 1 V / min is applied to both ends of the conductive thin film 3004 to locally apply the conductive thin film 3004. Electron emitting portion 300 that is destroyed, deformed, or altered, and is 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. When an appropriate voltage is applied to the conductive thin film 3004 after the energization forming process, electrons are emitted in the vicinity of the crack.

An example of the FE type is disclosed in, for example, W.S. P. D
yke & W. W. Dolan, "Fie-ld emi
session ", Advance in Electro
nPhysics, 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 FIG. 1, reference numeral 3010 denotes a substrate.
Reference numeral 3011 denotes an emitter wiring made of a conductive material. 3
012 is an emitter cone. Reference numeral 3013 denotes an insulating layer. 3014 is a gate electrode. The present device applies an appropriate voltage between the emitter cone 3012 and the gate electrode 3014, thereby forming the emitter cone 301.
Field emission is caused from the front end of the second.

As another element structure of the FE type, there is 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 a 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). A typical example of the MIM type element configuration is shown in a cross-sectional view of FIG.

In FIG. 1, reference numeral 3020 denotes a substrate. 3
Numeral 021 is a lower electrode made of metal. Reference numeral 3022 denotes a thin insulating layer having a thickness of about 100 angstroms. 3
Numeral 023 is an upper electrode made of a metal having a thickness of about 80 to 300 Å. In the MIM type, electrons are emitted from the surface of the upper electrode 3023 by applying an appropriate voltage between the upper electrode 3023 and the lower electrode 3021.

Each of the above-described cold cathode devices can emit 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 device, and a fine device can be manufactured. Further, even if a large number of elements are arranged on the 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 on applying cold cathode devices to various industrial products has been actively conducted.

For example, a surface conduction type electron-emitting device has the advantage that a large number of devices can be formed over a large area since the cold cathode device is particularly simple in structure and easy to manufacture among the above-mentioned cold cathode devices. Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 64-31332 by the present applicant, a method of appropriately driving a large number of surface conduction electron-emitting devices arranged on a substrate has been studied.

With respect to the application of the surface conduction electron-emitting device, for example, an image forming device such as an image display device or an image recording device, or a charged beam source has been studied.

Particularly, as an application to an image forming apparatus, for example, as disclosed in US Pat. No. 5,066,883, JP-A-2-257551 or JP-A-4-28137 by the present applicant, An image forming apparatus has been studied in which a surface conduction electron-emitting device is combined with a phosphor that emits light by an electron beam emitted from the device. An image forming apparatus formed by combining such a surface conduction electron-emitting device and a phosphor is expected to have better characteristics than other conventional image forming apparatuses. For example, compared to a liquid crystal display device that has become widespread in recent years, it can be said that it is superior in that it is self-luminous and does not need a so-called backlight, which illuminates the liquid crystal display device, and that it has a wide viewing angle. .

A method of driving a large number of FE type cold cathode devices is disclosed in, for example, US Pat.
04,895. Further, as an example in which the FE type is applied to an image forming apparatus, for example, R.F. The flat panel display reported by Meyer et al. Is known.
[R. Meyer: "Recent Development
ent on Microtips Display
at LETI ", Tech. Digest of 4
th Int. Vacuum Microele-c
tronics Conf. , Nagahama, p
p. 6-9 (1991)] An example in which a number of MIM types are arranged and applied to an image forming apparatus is disclosed in, for example, JP-A-3-55738 by the present applicant.

The present applicant and the inventors have tried cold cathode devices of various materials, manufacturing methods, and structures, including the invention described in the above-mentioned prior art. Furthermore, research is being conducted on a multi-electron beam source in which a large number of cold cathode devices are arranged, and on an image forming apparatus using the multi-electron beam source.

The inventors of the present application have tried a multi-electron beam source by an electric wiring method shown in FIG. 39, for example. That is, it is a multi-electron beam source in which a large number of cold cathode devices are two-dimensionally arranged and these devices are wired in a matrix as shown in the figure.

In the figure, 4001 schematically shows a cold cathode element, 4002 shows a row-direction wiring, 4003
Is a column wiring. Although the row direction wiring 4002 and the column direction wiring 4003 actually have a finite electric resistance, the wiring resistances 4004 and 4005 in FIG.
It is shown as The above-described wiring method is called simple matrix wiring.

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

In a multi-electron beam source in which cold cathode devices are arranged in a simple matrix, a row-direction wiring 4002 and a column-direction wiring 4003 are used to output a desired electron beam.
, An appropriate electric signal is applied. For example, in order to drive an arbitrary one row of the cold cathode elements in the matrix, the selection voltage Vs is applied to the row direction wiring 4002 of the selected row, and the non-selected state is applied to the row direction wiring 4002 of the non-selected row. Selection voltage Vn
Apply s. In synchronization with this, a driving voltage Ve for outputting an electron beam is applied to the column direction wiring 4003. According to this method, the wiring resistances 4004 and 4005
Is ignored, the voltage of Ve-Vs is applied to the cold cathode elements of the selected row, and the voltage of Ve-Vns is applied to the cold cathode elements of the non-selected rows. At this time, if Ve, Vs, and Vns are set to appropriate voltages, an electron beam having a desired intensity is output only from the cold cathode elements in the selected row. At this time, if a different drive voltage Ve is applied to each of the column wirings, an electron beam with a different intensity is output from each of the elements in the selected row. Also, by changing the length of time during which the drive voltage Ve is applied, the length of time during which the electron beam is output can be changed.

As described above, the multi-electron beam source in which the cold cathode devices are arranged in a simple matrix can be applied to various industrial products. For example, if an electric signal corresponding to image information is appropriately applied, the multi-electron beam source can be used for an image forming apparatus. Can be suitably used as an electron source.

[0025]

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

That is, as the demand for multimedia information devices increases with the development of computer technology and image processing technology, it is necessary to display various image sources in the image forming apparatus. The required image quality of the display image differs depending on the type of the image source to be obtained.

For example, an image displayed on a television (TV) generally has a so-called sharp image quality in which the whole image is bright, has high contrast, and has an enhanced outline.

Further, when the image quality is set to the same as that of the TV on the display screen of the display of the personal computer, problems such as deterioration of the focus of the display due to high luminance and fatigue of the eyes of the user due to high contrast occur. I will. For this reason, in the case of an image source from a personal computer or the like, the outline is generally not often emphasized.

Further, in the case of an image source from a game machine, since the luminance of the input image signal generally changes greatly,
It is not preferable to apply the brightness limitation by the ABL (Automatic Bright Limitter). In this case, it is preferable to set the contrast to be low and the brightness limitation by the ABL to be weak.

Therefore, the user needs to set the image quality every time the image source to be displayed is switched in order to set the image quality settings such as contrast and contour emphasis in an optimum setting state according to the image source desired to be displayed. .

Accordingly, it is an object of the present invention to provide an image forming apparatus which performs optimal image quality setting according to the type of an input image signal to be displayed.

[0032]

In order to achieve the above object, an image forming apparatus according to the present invention has the following configuration.

That is, storage means for storing image quality information relating to a plurality of types of image signals, determination means for determining the type of the input image signal, and, among the image quality information stored in the storage means, the determination result of the determination means Image quality correction means for correcting the input image signal according to corresponding image information.

Further, the image quality information includes at least contrast information, contour emphasis information, or ABL information, and the image quality correction means corrects the contrast of the input image signal based on the contrast information.
The method is characterized in that the contour of the image represented by the input image signal is enhanced based on the contour enhancement information, or the brightness of the image represented by the input image signal is limited based on the ABL information.

The plurality of types of image signals include:
An RGB primary color signal, an ENC signal, an S signal, and the like are assumed.

For example, the plurality of types of image signals are
The image quality information is at least a television signal and an RGB primary color signal, and the image quality information includes contrast information, contour emphasis information, and ABL (Automatic Bright Limitter) information. Is determined to be an RGB primary color signal, the contrast setting, the outline emphasis setting, and the ABL setting value may be reduced as compared to the case of a television signal.

For example, the plurality of types of image signals are
At least a television signal and an image signal from a game device, wherein the image quality information includes contrast information, contour emphasis information, and ABL (Automatic Bright Limitter) information; When it is determined that the image signal is an image signal from a game machine, at least the contrast setting may be reduced as compared with the case where the image signal is a television signal.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described. In the following description, first, the overall configuration of the image forming apparatus and its control processing will be described.
Next, a structure and a manufacturing method of a display panel applicable to the image forming apparatus will be described.

In this embodiment, R, G, B (red, green, and red) are used as a plurality of types of input image signals (image sources).
Blue) primary color signal s22, ENC (so-called NTSC R
Image signal before F modulation) s23, S (NTSC system, YC
The following description will be made on the assumption that there are four types of a front game input (ENC signal or S signal) signal s25 input from an input terminal (not shown) provided on the front surface of the image forming apparatus.

FIG. 1 is a block diagram showing the overall configuration of an image forming apparatus according to one embodiment of the present invention.

In the figure, reference numeral 1000 denotes an image display panel, for example, phosphors 480 in a horizontal direction (row direction) and 240 in a vertical direction (column direction) are arranged on a vertical stripe in the order of R, G, B. In addition, the electron-emitting devices corresponding to the respective phosphors are wired in a simple matrix by the row-direction wiring electrodes and the column-direction wiring electrodes. In the present embodiment, the display panel 1000 is driven line-sequentially.
The image display panel 1000 will be described later with reference to FIG.

A synchronizing signal is separated from the input image signal by a signal switching unit 28, and the synchronizing signal is converted to a signal line s26.
To the system controller 14 through

Based on the synchronization signal included in the input image signal, the system control unit 14 determines the type of the image signal input to the signal
That is, the currently connected external device is automatically determined.

Here, the operation of the signal switching unit 28 controlled by the system control unit 14 will be described.

FIG. 11 is a block diagram showing the configuration of the signal switching unit in one embodiment of the present invention.

As shown in FIG.
Includes a sync separation unit 29, a synchronization determination unit 30, and a video switching unit 31, and includes the R, G, and B primary color signals s22.
For signals other than the above, only the synchronization signal is separated by the synchronization separation unit 29. Then, the synchronization determination unit 30 determines the presence or absence of a video signal according to the presence or absence of the separated synchronization signal.

The system control unit 14 determines the input position of the input image signal based on the signal s26 indicating the presence or absence of the video signal by the synchronization determination unit 30, and determines the type of the external device based on the determined input position. Then, the system control unit 14 switches the video signal output by the video switching unit 31 according to the result of the type determination of the external device.

As described above, the system control unit 14 determines the type of the connected external device based on the input position of the input image signal. This determination method will be described with reference to FIG.

FIG. 2 is a flowchart showing the operation of the signal switching unit in one embodiment of the present invention.

In the figure, steps S1 and S
3: Whether or not the input image signal is the RGB signal s22
The determination is made according to the determination result of the presence / absence of the synchronization signal in the synchronization determination unit 30 represented by the signal s26 (step S1), and YE is determined.
In the case of S, processing is performed as an image source from the personal computer (step S3), and the process returns.

Step S2: NO in step S1
In this case (when the signal is not an RGB signal), it is determined whether or not the signal is the front game input signal s25 according to the result of the determination of the presence or absence of the synchronization signal in the synchronization determination unit 30 represented by the signal s26 (step S2), and YES Sometimes, processing is performed as an image source from the game device (step S4),
To return.

Step S5: NO in step S2
(When not the front game input signal s25), processing is performed as an image source from the TV of the ENCs23 or the S signal s24 (step S5), and the process returns.

Signals other than the R, G, and B signals s22 are decoded by the decoder 2 into analog R, G, and B signals, and the decoded analog signals of R, G, and B are respectively converted into analog preprocess units. 3 is input.

FIG. 5 is a block diagram showing a configuration of an analog preprocess according to an embodiment of the present invention. The analog pre-processing unit 3 shown in FIG.
3, a color adjustment circuit 34, a matrix circuit 35, a contrast control circuit 36, a DC reproduction circuit 37, a brightness circuit 38, a low-pass filter 39, and the like. The R, G, and B signals that have been reproduced and band-limited by the low-pass filter are converted into analog /
The signal is output to a digital (A / D) converter 4.

Here, a case where a game machine is connected and the contrast is reduced to １ ／ will be described. In this case, a microcomputer (not shown) of the system control unit 14 increases the contrast setting value of the television signal, which is the reference value, by a factor of two in the image quality setting processing (the flowchart of FIG. 4) described later. The set value thus set is set in the contrast control circuit 36 of the analog pre-processing unit 3 via the signals S13 and s14.

The system control unit 14 obtains an image source selection signal s12 according to a user's input operation on the user interface unit 16, and converts an input image signal of a type corresponding to the selection signal into a signal switching unit 28. To select.

In the analog pre-processing unit 3, the PLL
A synchronization signal for (Phase Locked Loop) is output from the synchronization separation circuit 33 to the timing control unit 5, and the R, G, and B signals output from the color adjustment circuit 34 are mixed by the matrix unit 35 to thereby provide luminance. Create a signal,
The luminance signal s20 is output to the video detector 13.

The A / D converters 4 provided for each of R, G, and B colors sample and
Based on the clock, the analog R, G, and B signals input from the analog preprocessing unit 3 are digitized with a predetermined number of gradations. The digitized digital image signal (multi-valued image data) s9 is input to the digital processing unit 6.

The digital processing section 6 performs general gamma processing and digital filter processing for contour enhancement and noise suppression on the input digital image signal. The processed digital image signal is processed by a data rearranging section. 7 is input.

Next, the contour emphasizing section included in the digital processing section 6 for performing contour emphasis will be described in detail.

FIG. 6 is a block diagram showing the configuration of the contour emphasizing unit in the digital processing unit according to one embodiment of the present invention. The contour emphasizing unit shown in FIG. 1 includes two line memories A (line memory 40) and two line memories B (line memory 41). These line memories store an input digital image signal in one adjacent line. The stored data is read out to the contour emphasizing signal synthesizing unit 42 at a predetermined timing. The contour emphasizing signal synthesizing section 42 generates a vertical outline emphasizing signal representing the vertical edge emphasis by a general method based on the data of the two lines, and an internal not-shown internal portion of the contour emphasizing signal synthesizing section 42. The shift register generates a horizontal contour emphasis signal representing the contour emphasis in the horizontal direction, further adds these contour emphasis signals, and outputs the result to the multiplier 43. The multiplier 43 takes the product of the contour emphasis amount set value from the system control unit 14 and the contour emphasis signal added in the contour emphasis signal synthesizing unit 42, and outputs the product to the adder 44. Then, the adder 44 receives the product data input from the multiplier 43 and the 1
The sum with the original image data for the line is obtained, and the sum is output to the data rearranging unit.

Here, for example, when the contour emphasis level is set to 0 in accordance with the type of input image data, the microcomputer of the system control unit 14 sets the contour emphasis amount set value to 0 by the signal s3 to the multiplier 43. By setting, control is performed so that the outline emphasis processing by the outline emphasis unit is not performed.

Next, the operation of the data rearranging section 7 will be described.

FIG. 7 is a timing chart for explaining the operation of the data rearranging unit in one embodiment of the present invention. As shown in FIG.
160 digital image signals s9 of each color of G and B are subjected to time axis compression as shown by serial image data s10, and digital image data input from the digital processing unit 6 in the order corresponding to the color arrangement of the phosphor. Is rearranged. The rearranged digital image data is transferred to the shift register 8 as 480 serial image data per line. The shift register 8 converts the input serial image data s10 into a shift clock s6.
And converts the serial image data into parallel data, and then sends it to the modulation signal generator 9 during the horizontal blanking period.

Next, the modulation signal generator 9 will be described. In the present embodiment, the modulation signal generator 9 employs a general pulse width modulation (PWM) method, and is provided with 480 pulse width modulators corresponding to one row of electron-emitting devices. . In the modulation signal generator 9, each pulse width modulator controls the pulse width modulation signal s7 during one horizontal period.
Is converted into a pulse signal having a time width proportional to the size of the image signal represented by the data, and the converted pulse signal is output to the horizontal drive driver 10. Horizontal drive driver 10
Outputs the voltage amplitude Ve of the pulse signal applied to the electron-emitting device inside the display panel 1000 according to the signal s17 from the Vf control unit 15.

FIG. 8 is a timing chart showing the display timing of each row synchronized with the vertical synchronizing signal in one embodiment of the present invention.

In FIG. 8, the shift register 11 includes:
A timing signal s8 (V_START, H_CLK) for row scanning output from the timing control unit 5 is input, and the shift register 1 according to the timing signal is input.
1 outputs to the vertical drive driver 12 a row selection signal for selecting any one of the row-direction wirings of a plurality of electron-emitting devices connected in a simple matrix in the display panel 1000.
The vertical drive driver 12 includes switch elements such as transistors for 240 rows, and any one of the switch elements is turned on by a row selection signal.
The bias voltage Vs output from the Vf control unit 15 is applied to the row wiring in the display panel 1000 corresponding to the row selection signal.

Here, the system control unit 14 that controls each of the above blocks will be described.

FIG. 9 is a block diagram showing the configuration of the system control unit according to one embodiment of the present invention.

As shown in FIG. 9, the system control unit 14 includes a CPU 21, a ROM 22, a RAM 23, an EEPRO
M24, A / D converter 25, D / A converter 26
And an I / O port 27. CPU 21
Controls the overall operation of the image forming apparatus according to a control program stored in the ROM 22 in advance. Also, E
In the EPROM 24, coefficients for each input of ABL, contrast, and brightness, that is, a correction amount, a set value of a television signal, and the like are stored in advance.
1 sets the optimum ABL, contrast, and brightness setting values corresponding to the input image signal to the EEPROM 24.
Is calculated based on the set value of the television signal and the correction amount stored in the.

The system controller 14 performs a process of reading out the image quality setting information and the correction amount information of the television stored in a memory (not shown) in advance.

FIG. 3 is a flowchart showing the image quality setting processing in one embodiment of the present invention. In the figure,
In steps S11 to S14, the type of the currently input image signal, which has been determined using the signal switching unit 28, is confirmed. If the input image signal is the RGB signal s22, the image quality setting processing in step S15 and the front game input signal s
In the case of 25, the process proceeds to the image quality setting process in step S16, in the case of the S signal s24, the image quality setting process in step S17, and in the case of the ENC signal s23, to the image quality setting process of step S18.

FIG. 4 is a flowchart showing the image quality setting processing in one embodiment of the present invention, and shows the details of the processing in steps S15 to S18 in FIG.

In the figure, steps S151 to S153: The set values of the television signal and the correction amounts of the respective image sources stored in the EEPROM 24 are read, and the product of the set values and the correction amounts is calculated.

Steps S154 to S156:
Contour emphasis setting is performed as described above, and contrast setting and ALB setting processing, which will be described later, are performed, and the process returns.

That is, in the image quality setting processing shown in FIG. 4, for example, RGB values are set according to the set values of the television signal stored as the reference values in the EEPROM 24 and the correction amounts stored for each image source. In the case of the signal s22, it is determined that the input is a personal computer input. When the correction amount is in the initial value (= 1), the contrast setting is reduced, the contour emphasis setting is reduced, and the ABL setting value is reduced. I do. Further, each correction amount at this time is, for example, a coefficient for setting the contrast to 1/2, setting the outline emphasis level to 0, and setting the ABL to 1/2 with respect to the image quality setting information of the television signal. It is.

Next, in the case of the front game input signal s25, it is determined that the game device is connected, and the correction amount information for displaying the image signal from the game device is stored in the EEPROM.
Read from 24. That is, when the correction amount is the initial value (= 1), the contrast is set to の of the image quality setting information of the television signal, the ABL set value is not changed (that is, the correction amount is 0), and the ABL is used. Make sure that restrictions are not too strong.

The S signal s24 and the ENC signal s23
In the case of, it is determined that the signal is a TV signal, and the image quality setting information of the television signal is set as it is, that is, the correction amount is set so that the contrast is high, the contour enhancement level is high, and the ABL setting value is high. Is set to 1.

The D / A converter 26 outputs a contrast control signal s13 and a brightness control signal s14 to the analog pre-processing unit 3 described above. These signals are used to control the levels of the R, G, and B signals and the amount of DC reproduction in the analog preprocessing unit 3 as described above. Further, the D / A converter 26 outputs a control signal s16 of the element applied voltage Vf to the Vf control unit 15. The output signal s18 of the D / A converter 26
Is a high voltage Va (s1) used for accelerating the electron beam.
9) is input to the high voltage generator 17 which outputs
The output level of a is controlled.

As described above, the image forming apparatus according to the present embodiment sequentially scans the image modulation data output from the horizontal drive driver 10 by the vertical drive driver 12 for each horizontal line, thereby providing a display panel. An image is formed at 1000.

The user interface unit 16
Is the contrast according to the type of the input image signal, AB
L, setting of a user-desired value used when performing automatic setting of image quality such as contour enhancement, and a change in the set amount are transmitted to the system control unit 14.
The display of various information from is performed.

For example, the user interface unit 16
In the above, when an item capable of changing the image quality setting value and the correction amount for each image source in the case of the above-described television signal is selected, the image quality adjustment setting corresponding to the television signal is performed in accordance with a user's input operation. The value or the correction amount of the set value is transmitted to the system control unit 14, and the system control unit 14 updates the value stored in the EEPROM 24 to the newly input value.

The video detecting section 13 converts the luminance signal s20 output from the analog pre-processing section 3 into a signal 1 to which horizontal blanking output from the timing control section 5 is added.
Integrating according to the gate signal s5 for each field (see FIG. 3), the average luminance signal s11 obtained by detecting the average value of the luminance signal s20 for each field is output to the system controller 14
Output to This average luminance s11 is calculated by the system controller 1
The signal is taken into the CPU 21 via the A / D converter 25 of No. 4 and the signal is compared by the CPU 21 with a reference value preset in the system control unit 14. Then, when the average luminance signal s11 is larger than the reference value, the CPU 21 performs the contrast control by outputting the output signal s13 of the D / A converter 26. As a result, the pulse width output from the horizontal drive driver 10 is suppressed, and the light emission luminance of the display panel 1000 is limited to a certain reference value or less. Here, for example, when it is desired to set the ABL to 1/2 of the television signal according to the type of the input image signal, the reference value is set to 1 /
By setting to 2, the set value of ABL can be set to ２.

FIG. 10 is a flowchart showing ABL processing in the system control unit according to one embodiment of the present invention.
22.

In the figure, steps S101 and S102: the average luminance signal s11 from the video detector 13
Is input (step S101), and the value of the average luminance signal is compared with a reference value 22a stored in the ROM 22 (step S102).

Steps S103 and S104: As a result of the comparison in step S102, when the average luminance is larger than the reference value (step S103), a signal is output to the D / A converter 26 and the output of the D / A converter 26 is output. The contrast control in the analog pre-processing unit 3 is performed by the signal s13 (step S104). As a result, the pulse width output from the horizontal drive driver 10 is suppressed, and the light emission luminance of the display panel 1000 is controlled to a certain reference value or less. Here, the reference value 22a is set to the EEPR
If the reference value is stored in the OM 24, the reference value can be rewritten. For example, by changing the reference value to 値 of the value of the television signal, the set value of the ABL can be changed to の of the television signal. Can be.

As described in the above-described embodiment, the contrast is controlled by the digital processing unit 6 in accordance with the coefficient data s15, and the Vf control unit 15 is controlled in accordance with the signal s16 output from the D / A converter 26. Alternatively, the value of Vf may be controlled, or the voltage value generated by the high voltage generator 17 may be controlled in accordance with the output signal s18 from the D / A converter 26.

Further, in order to obtain a luminance evaluation value, means for detecting an average high-voltage anode current is further provided inside the high-voltage generation section 17 or a supply current of a line for supplying power to the high-voltage generation section 17 is detected. In a case where a means is further provided and the detection signal s21 detected by the high voltage generation unit 17 is sent to the system control unit 14 for control, the above-described step S10 is performed.
In step 1, the detection signal s21 may be input to the CPU 21 and the processing after step S102 may be executed according to the input value. In this case, the value represented by the signal s21 is processed in the same manner as the average luminance signal s11 in FIG.

As described above, according to the image forming apparatus according to the present embodiment, the image quality is automatically adjusted to the optimum image quality according to the type of the input image signal, that is, the image source. This eliminates eyestrain caused by the image quality not being adjusted to a desirable state.

(Structure and Manufacturing Method of Display Panel) The structure and manufacturing method of a display panel applicable to the image forming apparatus according to the present invention will be described with reference to specific examples.

FIG. 12 is a perspective view of a display panel applicable to the present invention, and corresponds to the image display panel 1000 in each of the above-described embodiments. The display panel shown in FIG.
A part of the panel is cut away to show the internal structure.

In the figure, 1005 is a rear plate, 1006
Denotes a side wall, and 1007 denotes a face plate. The structure of the rear plate 1005 to the face plate 1007 forms an airtight container for maintaining the inside of the display panel at a vacuum.

In assembling this airtight container,
It is necessary to seal the joints of each member to maintain sufficient strength and airtightness.For example, frit glass is applied to the joints, and the joints are sealed in air or nitrogen atmosphere in Celsius. Sealing is achieved by baking at 400 to 500 degrees for 10 minutes or more. A method for evacuating the inside of the hermetic container to a vacuum will be described later.

The rear plate 1005 has a substrate 1001
Is fixed, but the cold cathode device 1002 is provided on the substrate.
Are formed in N × M pieces. However, 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 an image forming apparatus for displaying high-definition television, N = 3000, M = 1
It is desirable to set the number to 000 or more. In this embodiment, N = 3072 and M = 1024.

The N × M cold cathode devices are arranged in a simple matrix by M row-directional wirings 1003 and N column-directional wirings 1004. Hereinafter, the above-described substrate 1001, the cold cathode device 1002, and the M row-direction wirings 10
03 and a portion constituted by the N column direction wirings 1004 are referred to as a multi-electron beam source. The method and structure of the multi-electron beam source will be described later.

In the present embodiment, the substrate 1001 of the multi-electron beam source is fixed to the rear plate 1005 of the airtight container.
If 1 has sufficient strength, the substrate 100 of the multi-electron beam source is used as a rear plate of the hermetic container.
1 itself may be used.

Further, on the lower surface of the face plate 1007, a fluorescent film 1008 is formed. Since the image forming apparatus according to the present embodiment is a color display, the fluorescent film 10
08 is the red, green, blue,
The three primary color phosphors are separately applied. The phosphors of each color are separately applied in stripes as shown in FIG. 13, for example, and a black conductor 1010 is provided between the stripes of the phosphors. The purpose of providing the black conductor 1010 is to prevent the display color from being shifted even if there is a slight shift in the irradiation position of the electron beam, and to prevent the reflection of external light to improve the contrast of the displayed image. It is to prevent the phosphor film from being lowered, and to prevent charge-up of the fluorescent film by the electron beam. The black conductor 1010 has
Although graphite is used as a main component, other materials may be used as long as they are 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. 3, but may be, for example, a delta arrangement as shown in FIG. 14 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 known in the CRT field 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 1
008, to act as an electrode for applying an electron beam acceleration voltage,
To act as a conductive path for the excited electrons. 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. 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, the gap between the face plate substrate 1007 and the fluorescent film 1008 is applied for the purpose of applying an acceleration voltage and improving the conductivity of the fluorescent film.
For example, a transparent electrode made of ITO may be provided.

Dx1 to Dxm and Dy1 to Dyn and Hv
Is a terminal for electric connection of an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown).
Dx1 to Dxm are the row direction wirings 100 of the multi-electron beam source.
3. Dy1 to Dyn are column wirings 10 of the multi-electron beam source.
04 is electrically connected. Hv is electrically connected to the metal back 1009 of the face plate.

To evacuate the inside of the hermetic container to a vacuum, after assembling the hermetic container, an exhaust pipe (not shown) and a vacuum pump are connected, and the inside of the hermetic container is raised to 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. Here, 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, and the inside of the airtight container is 1 × 10−5 due to the adsorbing action of the getter film. Alternatively, the degree of vacuum is maintained at 1.times.10.sup.-7 [Torr].

The basic configuration and manufacturing method of the display panel in this embodiment have been described.

Next, a method of manufacturing the multi-electron beam source used for the display panel shown in FIG. 12 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 in the image forming apparatus described later is an electron source in which cold cathode devices are arranged in a simple matrix. Therefore, for example, a surface conduction type emission element, an FE type,
Alternatively, a cold cathode element such as an MIM type can be used.

However, in a situation where an inexpensive image forming apparatus having a large display screen 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, an extremely high-precision manufacturing technique is required. Therefore, it is a disadvantageous factor in achieving an increase in area and a reduction in manufacturing cost. Further, in the MIM type, it is necessary to make the thickness of the insulating layer and the upper electrode thin and uniform, which is also a disadvantageous factor in achieving a large area and a reduction in manufacturing cost. That point,
Since the surface conduction electron-emitting device is relatively simple to manufacture,
It is easy to increase the area and reduce the manufacturing cost. In addition, the present 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-brightness, large-screen image forming apparatus. Therefore, in the display panel of this embodiment, a surface conduction electron-emitting device in which the electron-emitting portion or its peripheral portion is formed of a fine particle film is used. Therefore, the basic configuration, manufacturing method and characteristics of a suitable surface conduction electron-emitting device will be described first, and then the structure of a multi-electron beam source in which a large number of devices are arranged in a simple matrix will be described.

(Preferable 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. Types.

(Flat-Type Surface-Conduction-Type Emission Element) First, the structure and manufacturing method of a flat-type surface-conduction-type emission element will be described.

FIG. 15 is a plan view for explaining the structure of a planar surface conduction electron-emitting device applicable to the present invention. FIG. 16 is a cross-sectional view illustrating a configuration of a planar surface conduction electron-emitting device applicable to the present invention.

15 and 16, 1101 is a substrate, 1102 and 1103 are device electrodes, 1104 is a conductive thin film, 1105 is an electron emitting portion formed by energization forming, and 1113 is a thin film formed by energization activation. is there.

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 element electrodes 1102 and 1103 provided on the substrate 1101 so as to be parallel to the substrate surface are formed of a conductive material. For example, N
i, Cr, Au, Mo, W, Pt, Ti, Cu, Pd,
Materials may be appropriately selected from metals such as Ag or the like, alloys of these metals, metal oxides such as In 2 O 3 —SnO 2, semiconductors such as polysilicon, and the like. The electrodes can be easily formed by using a combination of a film forming technique such as vacuum deposition and a patterning technique such as photolithography and etching. However, the electrodes can be formed using other methods (for example, printing techniques). Is also good.

The shapes of the device electrodes 1102 and 1103 are appropriately designed according to the application purpose of the electron-emitting device.
In general, the electrode interval L is usually designed by selecting an appropriate value from the range of several hundred angstroms to several hundred micrometers. It is in the range of tens of 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 particles are spaced apart, a structure in which the particles are adjacent to each other, or a structure in which the particles overlap each other is observed.

The particle size of the fine particles used in the fine particle film is in the range of several Angstroms to several thousand Angstroms, and preferably in the range of 10 Angstroms to 200 Angstroms. Further, the thickness of the fine particle film is appropriately set in consideration of various conditions described below. That is, the device electrode 1102
Alternatively, conditions necessary for good electrical connection with 1103, conditions necessary for satisfactorily performing energization forming described later, conditions necessary for setting the electrical resistance of the fine particle film itself to an appropriate value described later, And so on.

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, A
u, Ti, In, Cu, Cr, Fe, Zn, Sn, T
a, W, Pb, and other metals, PdO, Sn
Oxides such as O2, In2 O3, PbO, Sb2 O3, etc., HfB2, ZrB2, LaB6, CeB
Borides such as 6, YB4, GdB4, etc .;
Carbides such as iC, ZrC, HfC, TaC, SiC, WC, etc., nitrides such as TiN, ZrN, HfN, etc., semiconductors such as Si, Ge, etc., carbon, etc. And these 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].

Note that the conductive thin film 1104 and the device electrode 110
2 and 1103 are desirably electrically connected well, and therefore have a structure in which a part of each overlaps. In the example of FIG. 15 and FIG. 16, the overlapping is performed in the order of the substrate, the device electrode, and the conductive thin film from the bottom, but in some cases, the substrate, the conductive thin film, and the device electrode are sequentially stacked from the bottom. They may be stacked.

The electron emitting portion 1105 is a crack-like portion formed in a part of the conductive thin film 1104, and has an electrical property higher than that of 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 FIGS. 15 and 16.

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

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

Since it is difficult to accurately show the actual position and shape of the thin film 1113, it is schematically shown in FIGS. Further, in the plan view of FIG. 15, an element in which a part of the thin film 1113 is removed is illustrated.

The basic structure of the preferred device has been described above. In this example, the following device was used.

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

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 method of manufacturing a suitable flat surface conduction electron-emitting device will be described. 17 to 21 are cross-sectional views for explaining a manufacturing process of a planar type surface conduction electron-emitting device applicable to the present invention, and reference numerals of members in each drawing are the same as those in FIGS. 15 and 16. .

1) First, as shown in FIG.
Element electrodes 1102 and 1103 are formed on the substrate 01. Before forming, the substrate 1101 is washed with a detergent,
After sufficiently washing with pure water and an organic solvent, the material for the device electrode is deposited. Here, as a deposition method, for example, a vacuum deposition technique such as an evaporation method or a sputtering method may be used. Thereafter, the deposited electrode material is patterned by using a photolithography / etching technique to form a pair of device electrodes (1102 and 1103) shown in FIG.

2) Next, as shown in FIG. 18, a conductive thin film 1104 is formed. In the formation, first, an organic metal solution is applied to the substrate in the state shown in FIG. 17 and dried, and the dried substrate is heated and baked to form a fine particle film, and then a predetermined film is formed by photolithography and etching. Is patterned. Here, the organometallic solution is a solution of an organometallic compound whose main element is a material of fine particles used for the conductive thin film. Specifically, in this example, Pd was used as a main element. In this embodiment, the dipping method is used as the coating method, but other methods such as a spinner method and a spray method may be used.

As a method for forming a conductive thin film made of a fine particle film, a method other than the method of applying an organometallic solution used in this embodiment, for example, a vacuum evaporation method, a sputtering method, or a chemical vapor deposition method Method may be used.

3) Next, as shown in FIG. 19, an appropriate voltage is applied between the device electrodes 1102 and 1103 from a forming power supply 1110, and a current forming process is performed to form an electron emitting portion 1105.

Here, the energization forming treatment is suitable for applying an electric current to the conductive thin film 1104 made of a fine particle film to break, deform, or alter a part of the conductive thin film 1104 as appropriate to emit electrons. This is the process of changing the structure. A portion of the conductive thin film made of the 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.
Incidentally, when compared with before the electron emission portion 1105 is formed,
After the formation, the electric resistance measured between the device electrodes 1102 and 1103 greatly increases.

FIG. 22 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 between triangular-wave pulses at appropriate intervals, and the current flowing at that time is measured by an ammeter 1111.
Was measured.

In this embodiment, for example, in a vacuum atmosphere of about 10 −5 [torr], for example, the pulse width T1 is set to 1 [millisecond] and the pulse interval T2 is set to 10
[Milliseconds], and the peak value Vpf is set to 0.1 for each pulse.
The voltage was increased by [V]. Then, each time five triangular waves were applied, the monitor pulse Pm was inserted at a rate of once. The monitor pulse voltage Vpm was set to 0.1 [V] so as not to adversely affect the forming process. The electric resistance between the device electrodes 1102 and 1103 is 1
The current measured by the ammeter 1111 at the stage when the power reaches x10 6 [ohm], that is, when the monitor pulse is applied, is 1 × 10
When the current value became equal to or less than the minus 7th power [A], the energization related to the forming process was terminated.

The above method is a preferable method for the surface conduction electron-emitting device of the present embodiment, and 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. 20, an appropriate voltage is applied between the element electrodes 1102 and 1103 from the activating power supply 1112, and a current activation process is performed to improve the electron emission characteristics. I do.

Here, 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 FIG. 20, a deposit made of carbon or a carbon compound is schematically shown as a member 1113. In addition, by performing the energization activation process, the emission current at the same applied voltage can be typically increased by 100 times or more compared to before the energization activation process.

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. 23 shows an example of an appropriate voltage waveform applied from the activation power supply 1112 in order to describe the energization method in more detail. In the present embodiment, the energization activation process is performed by periodically applying a rectangular wave of a predetermined voltage.
Specifically, the voltage Vac of the rectangular wave was 14 [V], the pulse width T3 was 1 [millisecond], and the pulse interval T4 was 10 [millisecond]. It should be noted that 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, it is desirable to appropriately change the conditions accordingly.

Reference numeral 1114 shown in FIG. 20 denotes an anode electrode for capturing the emission current Ie emitted from the surface conduction electron-emitting device.
16 are connected. Note that, when the activation process is performed after the substrate 1101 is 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 process, and control the operation of the activation power supply 1112. FIG. 24 shows an example of the emission current Ie measured by the ammeter 1116. Referring to FIG.
When the pulse voltage starts to be applied from time to time, the emission current Ie increases with 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. If 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. 21 was manufactured.

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

FIG. 25 is a schematic sectional view for explaining the basic structure of a vertical surface conduction electron-emitting device applicable to the present invention.

In the figure, reference numeral 1201 denotes a substrate;
Reference numeral 3 denotes an element electrode; 1206, a step forming member; 1204, a conductive thin film using a fine particle film; 1205, an electron emitting portion formed by energization forming; and 1213, a thin film formed by energization activation.

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 FIGS. 15 and 16 is set as the step height Ls of the step forming member 1206 in the vertical type. In addition, the substrate 1201, the element electrode 1
202 and 1203, conductive thin film 12 using fine particle film
For 04, the materials listed in the description of the planar type can be similarly used. For the step forming member 1206, an electrically insulating material such as SiO2 is used.

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

FIGS. 26 to 31 are cross-sectional views illustrating the steps of manufacturing a vertical surface conduction electron-emitting device applicable to the present invention. The reference numerals of the members in each drawing are the same as those in FIG. .

1) First, as shown in FIG.
The element electrode 1203 is formed over the element 01.

2) Next, as shown in FIG. 27, an insulating layer for forming a step forming member is laminated. The insulating layer may be formed by stacking, for example, SiO2 by sputtering, but other film forming methods such as, for example, vacuum evaporation or printing may be used.

3) Next, as shown in FIG. 28, an element electrode 1202 is formed on the insulating layer.

4) Next, as shown in FIG. 29, a part of the insulating layer is removed by, for example, an etching method to expose the element electrode 1203.

5) Next, as shown in FIG. 30, a conductive thin film 1204 using a fine particle film is formed. For the formation, as in the case of the flat type described above, a film forming technique such as a coating method may be used.

6) Next, as in the case of the above-described flat type, the energization forming process is performed to form an electron emitting portion. Specifically, a process similar to the planar energization forming process described with reference to FIG. 19 may be performed.

7) Next, as in the case of the above-mentioned flat type, a current activation process is performed to deposit carbon or a carbon compound in the vicinity of the electron emitting portion. Specifically, a process similar to the planar energization activation process described with reference to FIG. 20 may be performed.

Through the above steps, the vertical surface conduction electron-emitting device shown in FIG. 31 was manufactured.

(Characteristics of Surface Conduction Emission Element Used in Image Forming Apparatus) Next, characteristics of the element used in the image forming apparatus according to this embodiment will be described.

FIG. 32 is a diagram showing a change in the emission current Ie during the energization activation process applicable to the present invention.
e) vs. (device applied voltage Vf) characteristics and (device current I
f) A typical example of the characteristic versus the (applied voltage Vf) is shown.
Note that the emission current Ie is significantly smaller than the device current If, and it is difficult to show the same current on the same scale. In addition, these characteristics are changed by changing design parameters such as the size and shape of the device. Therefore, the two graphs are shown in arbitrary units.

The element used in the image forming apparatus in this embodiment has the following three characteristics regarding the emission current Ie.

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

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

Third, since the response speed of the current Ie emitted from the element is fast 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 for applying the voltage Vf. Can control.

Because of the above characteristics, the surface conduction electron-emitting device can be suitably used in an image forming apparatus. For example, in an image forming apparatus provided with a number of elements 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, a voltage equal to or higher than the threshold voltage Vth is appropriately applied to the element being driven, and a voltage lower than the threshold voltage Vth is applied to the element in a non-selected state. 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 a large number of elements are arranged in a simple matrix) Next, a structure of a multi-electron beam source in which the above-mentioned surface conduction electron-emitting elements are arranged on a substrate and arranged in a simple matrix will be described.

FIG. 33 is a plan view of a multi-electron beam source applicable to the present invention, and is a plan view of a multi-electron beam source used for the display panel of FIG. Fig. 1
A plurality of surface conduction type emission elements similar to the elements shown in FIGS. 5 and 16 are arranged. These elements are wired in a simple matrix by row-directional wiring electrodes 1003 and column-directional wiring electrodes 1004. An insulating layer (not shown) is formed between the row-directional wiring electrodes 1003 and the column-directional wiring electrodes 1004 where the electrodes intersect, so that electrical insulation is maintained.

FIG. 34 is a cross-sectional view of the surface conduction electron-emitting device applicable to the present invention, taken along a line AA ′ in FIG. A multi-electron source having a structure as shown in FIG. 1 has a row-direction wiring electrode 1003, a column-direction wiring electrode 1004, an interelectrode insulating layer (not shown), a device electrode of a surface conduction electron-emitting device, and a conductive material. After the conductive thin film was formed, power was supplied to each element via the row-direction wiring electrodes 1003 and the column-direction wiring electrodes 1004 to perform the energization forming process and the energization activation process.

<Image Forming Apparatus> FIG. 35 is a block diagram showing a configuration example of an image forming apparatus using a multi-electron beam source applicable to the present invention as a display panel. 1 is a diagram illustrating an example of an image forming apparatus configured to be able to display image information provided from various image information sources such as a television broadcast on a display panel using the source.

In the figure, 70 is a display panel, 71 is a drive circuit of the display panel 70, 72 is a display controller, 73 is a multiplexer,
4 is a decoder, 75 is an input / output interface circuit, 76
Denotes a CPU, 77 denotes an image generation circuit, 78, 79 and 80
Is an image memory interface circuit, 81 is an image input interface circuit, 82 and 83 are TV signal receiving circuits, 8
Reference numeral 4 denotes an input unit. When the image forming apparatus receives a signal including both video information and audio information such as a television signal, the image forming apparatus naturally reproduces the audio simultaneously with the display of the video. Descriptions of circuits, speakers, and the like relating to reception, separation, reproduction, processing, storage, and the like of audio information that is not directly related to the features are omitted.

The function of each section will be described below along the flow of image signals in the image forming apparatus shown in FIG.

First, the TV signal receiving circuit 83, for example,
This 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 the TV signal to be received is not particularly limited.
Various systems such as the NTSC system, the PAL system, and the SECAM system may be used. Further, a TV signal composed of a larger number of scanning lines (for example, a so-called high-definition TV including the MUSE method) 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 83 is output to the decoder 74.

The TV signal receiving circuit 82 is a circuit for receiving a TV image signal transmitted using a wired transmission system such as a coaxial cable or an optical fiber. The format of the received TV signal is not particularly limited. In addition, the T
The V signal is also output to the decoder 74.

The image input interface circuit 81
Is a circuit that captures an image signal supplied from an image input device such as a TV camera or an image reading scanner. The captured image signal is output to the decoder 74.

The image memory interface circuit 80
Is a circuit for capturing an image signal stored in a video tape recorder (hereinafter abbreviated as VTR). The captured image signal is output to a decoder 74.

The image memory interface circuit 79
Is a circuit for taking in an image signal stored in the video disk, and the taken-in image signal is output to the decoder 74.

Also, the image memory interface circuit 78
Is a circuit for taking in an image signal from a device that stores still image data, such as a so-called still image disk. The taken still image data is input to the decoder 74.

Also, the input / output interface circuit 75
A circuit that connects the image forming apparatus to an external computer, a computer network, or an output device such as a printer. It goes without saying that image data and character / graphic information are input / output, and in some cases, control signals and numerical data can be input / output between the CPU 76 provided in the image forming apparatus and the outside. is there.

The image generating circuit 77 is used for display based on image data and character / graphic information input from the outside via the input / output interface circuit 75, or image data and character / graphic information output from the CPU 76. This is a circuit for generating image data. The circuit includes, for example, a rewritable memory for storing image data and character / graphic information, a read-only memory storing an image pattern corresponding to a character code, a processor for performing image processing, and the like. And other circuits necessary for generating an image.

The display image data generated by this circuit is output to the decoder 74, but may be output to an external computer network or printer via the input / output interface circuit 75 in some cases.

The CPU 76 mainly performs operations related to operation control of the image forming apparatus and generation, selection, and editing of a display image. The CPU 76 outputs a control signal to the multiplexer 73, for example, and appropriately selects and combines image signals to be displayed on the display panel. At that time, a control signal is generated to the display panel controller 72 in accordance with the image signal to be displayed, and the screen display frequency, the scanning method (for example, interlaced or non-interlaced), and the number of scanning lines on one screen are determined. The operation of the image forming apparatus is appropriately controlled.

The image data and character / graphic information are directly output to the image generation circuit 77, or an external computer or memory is accessed via the input / output interface circuit 75 to access the image data or character / graphic information. Enter

It is to be noted that the CPU 76 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 75 as described above, and work such as numerical calculation may be performed in cooperation with an external device.

The input section 84 is for the user to input commands, programs, data, and the like to the CPU 76. For example, in addition to a keyboard and a mouse, a joystick, a bar code reader, a voice recognition device, etc. Input devices can be used.

The decoder 74 includes an image generation circuit 77
And a circuit for inversely converting various image signals input from the TV signal receiving circuit 83 into three primary color signals or a luminance signal and I and Q signals. As shown by the dotted line in FIG.
The decoder 74 desirably includes an image memory therein. This is for handling television signals that require an image memory when performing inverse conversion, such as the MUSE method. Further, the provision of the image memory facilitates display of a still image, or facilitates image processing and editing including image thinning, interpolation, enlargement, reduction, and synthesis in cooperation with the image generation circuit 77 and the CPU 76. This is because the advantage of being able to do so is born.

The multiplexer 73 includes a CPU 76
A display image is appropriately selected based on a control signal input from the controller. That is, the multiplexer 73 is connected to the decoder 7.
A desired image signal is selected from among the inversely converted image signals input from 4 and output to the drive circuit 71. 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 7
Reference numeral 2 denotes a circuit that controls the operation of the drive circuit 71 based on a control signal input from the CPU 76.

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 71.

Further, as a signal relating to the driving method of the display panel, a signal for controlling, for example, a screen display frequency and a scanning method (for example, interlace or non-interlace) is output to the drive circuit 71.

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 71.

The drive circuit 71 is a circuit for generating a drive signal to be applied to the display panel 70, and operates based on an image signal input from the multiplexer 73 and a control signal input from the display panel controller 72. Things.

The function of each section has been described above. With the configuration illustrated in FIG. 35, in the present image forming apparatus, image information input from various image information sources can be displayed on the display panel 70. . That is, various image signals such as television broadcasts are inversely converted by the decoder 74, then appropriately selected by the multiplexer 73, and the selected image signals are input to the drive circuit 71. On the other hand, the display controller 72 generates a control signal for controlling the operation of the drive circuit 71 according to the image signal to be displayed. The drive circuit 71 applies a drive signal to the display panel 70 based on the image signal and the control signal. Thus, an image is displayed on the display panel 70. These series of operations are performed by the CPU
76 to control the entire system.

Further, in the present image forming apparatus, not only the image memory incorporated in the decoder 74, the image generation circuit 77 and the information selected from the information are displayed, but also the image information to be displayed is enlarged, for example. , Reduction, rotation, movement, edge enhancement, thinning, interpolation, color conversion, image aspect ratio conversion, etc., synthesis, erasure, connection,
It is also possible to perform image editing such as exchanging and fitting.

Although not particularly described in the description of this 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 image forming apparatus can be used as a television broadcast display device, a video conference terminal device, an image editing device that handles still images and moving images, a computer terminal device,
The functions of office terminal equipment such as a word processor, a game machine, and the like can be provided as a single unit, and the application range is extremely wide for industrial use or consumer use.

FIG. 35 shows only an example of the configuration of an image forming apparatus using a display panel using a surface conduction electron-emitting device as an electron beam source, and the present invention is not limited to this. Needless to say. For example, among the components in FIG. 35, 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 image forming apparatus is applied to a videophone, it is preferable to add a transmission / reception circuit including a television camera, an audio microphone, an illuminator, and a modem to the components.

In the present image forming apparatus, the depth of the image forming apparatus can be reduced because the thickness of the display panel using the surface conduction electron-emitting device as an electron source can be easily reduced. In addition, since the display panel using the surface conduction electron-emitting device as the electron beam source is easy to enlarge the screen, has high brightness, and has excellent viewing angle characteristics, the image forming apparatus has a realistic and powerful image. Can be displayed with good visibility.

Incidentally, the electron-emitting devices constituting the electron source include:
The present invention can be applied not only to a surface conduction electron-emitting device but also to a general low-impedance device as long as it has a non-linear voltage V / current I characteristic as shown in FIG.

Further, in the above-described embodiment, the current drive circuit is arranged in the column direction wiring, and the determined current flows in the column direction wiring. However, the current drive circuit may be arranged in the row direction wiring. Good.

[0200]

As described above, according to the present invention,
It is possible to provide an image forming apparatus that performs optimal image quality setting according to the type of an input image signal to be displayed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an image forming apparatus as one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of a signal switching unit according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating an image quality setting process according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an image quality setting process according to an embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of an analog preprocess according to an embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a contour emphasis unit in a digital processing unit according to an embodiment of the present invention.

FIG. 7 is a timing chart illustrating an operation of a data rearranging unit according to the embodiment of the present invention.

FIG. 8 is a timing chart showing display timing of each row synchronized with a vertical synchronization signal according to an embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of a system control unit according to an embodiment of the present invention.

FIG. 10 is a flowchart illustrating ABL processing in a system control unit according to an embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration of a signal switching unit according to an embodiment of the present invention.

FIG. 12 is a perspective view of a display panel applicable to the present invention.

FIG. 13 is a plan view illustrating a phosphor array of a face plate of the display panel.

FIG. 14 is a plan view illustrating a phosphor array of a face plate of a display panel.

FIG. 15 is a plan view illustrating the configuration of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 16 is a cross-sectional view illustrating a configuration of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 17 is a cross-sectional view for explaining a manufacturing process of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 18 is a cross-sectional view for explaining a manufacturing process of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 19 is a cross-sectional view for explaining a manufacturing process of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 20 is a cross-sectional view for explaining a manufacturing process of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 21 is a cross-sectional view for explaining a manufacturing process of a planar surface conduction electron-emitting device applicable to the present invention.

FIG. 22 is a diagram showing an applied voltage waveform in the energization forming process.

FIG. 23 is a diagram showing an applied voltage waveform in the energization activation process.

FIG. 24 is a diagram showing a change in emission current Ie during the activation process.

FIG. 25 is a schematic cross-sectional view for explaining a basic configuration of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 26 is a cross-sectional view illustrating a manufacturing process of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 27 is a cross-sectional view illustrating a manufacturing process of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 28 is a cross-sectional view illustrating a manufacturing process of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 29 is a cross-sectional view illustrating a manufacturing process of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 30 is a cross-sectional view illustrating a manufacturing process of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 31 is a cross-sectional view illustrating a manufacturing process of a vertical surface conduction electron-emitting device applicable to the present invention.

FIG. 32 is a diagram showing a change in emission current Ie during a current activation process applicable to the present invention.

FIG. 33 is a plan view of a multi-electron beam source applicable to the present invention.

FIG. 34 shows a surface conduction electron-emitting device applicable to the present invention;
FIG. 34 is a cross-sectional view taken along the line AA ′ of FIG. 33.

FIG. 35 is a block diagram illustrating a configuration example of an image forming apparatus using a multi-electron beam source applicable to the present invention as a display panel.

FIG. 36 is a plan view showing a structural example of a general surface conduction electron-emitting device.

FIG. 37 is a cross-sectional view showing a structural example of a general FE type cold cathode element.

FIG. 38 is a cross-sectional view showing a structural example of a general MIM cold-cathode device.

FIG. 39 is a diagram showing a wiring example of a plurality of electron-emitting devices arranged in a matrix.

[Explanation of symbols]

 2: Decoder, 3: Analog pre-processing section, 4: A / D converter, 5: Timing control section, 6: Digital processing section, 7: Data rearrangement section, 8, 11: Shift register, 9: Modulation signal generation section , 10: horizontal drive driver, 12: vertical drive driver, 13: video detection unit, 14: system control unit, 15: Vf control unit, 16: user interface unit, 17: high voltage generation unit, 21: CPU, 22: ROM , 23: RAM, 24: EEPROM, 25: A / D, 26: D / A, 27: I / O, 28: signal switching unit, 29: synchronization separation unit 1, 30: synchronization determination unit, 31: synchronization switching Unit, 32: video switching unit, 33: sync separation unit 2, 34: color adjustment unit, 35: matrix unit, 36: contrast control unit, 37: straight line Stream regeneration unit, 38: brightness unit, 39: low-pass filter unit, 40: 1 line memory A, 41: 1 line memory B, 42: contour emphasis signal synthesis, 43: multiplier, 44: adder,

Continued on front page F-term (reference) 5B057 AA11 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC01 CE03 CE11 CE17 CH11 CH18 DB02 DB06 DB09 DC16 5C026 CA02 CA03 CA10 5C066 AA03 AA09 CA17 EA07 EA10 EC02 GA01 5C080 EA03 EB05 JJ05 JJ06 JJ07

Claims (17)

[Claims] A storage unit configured to store image quality information relating to a plurality of types of image signals; a determination unit configured to determine a type of the input image signal; and a determination result of the determination unit among the image quality information stored in the storage unit. An image forming apparatus comprising: an image quality correction unit configured to correct the input image signal according to corresponding image information. 2. The image forming apparatus according to claim 1, wherein the image quality information includes at least contrast information. 3. The image forming apparatus according to claim 1, wherein the image quality information includes at least outline emphasis information. 4. The image quality information includes at least ABL (Au
2. The image forming apparatus according to claim 1, wherein the image forming apparatus includes tomatic bright limitter information. 5. The image forming apparatus according to claim 2, wherein the image quality correction unit corrects a contrast of the input image signal based on the contrast information. 6. The image forming apparatus according to claim 3, wherein the image quality correction unit performs contour enhancement of an image represented by the input image signal based on the contour enhancement information. 7. The image forming apparatus according to claim 4, wherein the image quality correction unit limits the brightness of an image represented by the input image signal based on the ABL information. 8. The image forming apparatus according to claim 7, wherein said image quality correcting means also controls the brightness of an image represented by said input image signal by contrast control. 9. The image forming apparatus according to claim 1, wherein the plurality of types of image signals include RGB primary color signals. 10. The image signal of the plurality of types includes an ENC
The image forming apparatus according to claim 1, wherein the image forming apparatus includes a signal. 11. The image forming apparatus according to claim 1, wherein the plurality of types of image signals include an S signal. 12. The plurality of types of image signals are at least a television signal and an RGB primary color signal, and the image quality information is contrast information, contour emphasis information,
BL (Automatic Bright Limiter) information, wherein the image quality correction means, when the determination means determines that the input image signal is an RGB primary color signal, 2. The image forming apparatus according to claim 1, wherein the setting of contrast is reduced, the setting of edge enhancement is reduced, and the set value of ABL is reduced. 13. The image signal of a plurality of types is at least a television signal and an image signal from a game device, wherein the image quality information is contrast information, contour emphasis information, A
BL (Automatic Bright Limiter) information, wherein the image quality correction means compares the input image signal with a television signal when the determination means determines that the input image signal is an image signal from a game device. 2. The image forming apparatus according to claim 1, wherein the setting of the contrast is reduced at least. 14. The image forming apparatus according to claim 1, further comprising an input unit capable of changing image information stored in said storage unit. 15. The image quality correction means controls an anode voltage of a cathode ray tube included in the display, so that A
8. The image forming apparatus according to claim 7, wherein control of the BL is performed. 16. The image forming apparatus according to claim 1, wherein the display includes a plurality of cold cathode electron sources. 17. The image quality correcting means controls an ABL (Automati
17. The image forming apparatus according to claim 16, wherein control of (c Bright Limitter) is performed.