JP3581581B2 - Image display device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming method and apparatus by irradiating a luminous body with an electron beam.
[0002]
[Prior art]
Conventionally, two types of electron-emitting devices, a hot cathode device and a cold cathode device, are known. Among them, as the cold cathode device, for example, a surface conduction type emission device, a field emission type device (hereinafter referred to as FE type), a metal / insulating layer / metal type emission device (hereinafter referred to as MIM type), and the like are known. .
[0003]
As the surface conduction type emission element, for example, M.I. I. Elinson, Radio Eng. Electron Phys. , 10, 1290, (1965) and other examples described later.
[0004]
The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. As this surface conduction type emission element, SnO by Elinson et al.₂In addition to those using thin films, those using Au thin films [G. Dittmer: “Thin Solid Films”, 9, 317 (1972)], In₂O₃/ SnO₂By a thin film [M. Hartwell and C.I. G. FIG. Fonstad: "IEEE Trans. ED Conf.", 519 (1975)], and those using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, 22 (1983)] and the like are reported.
[0005]
FIG. 21 shows a typical example of the element configuration of these surface conduction electron-emitting devices. 1 shows a plan view of a device by Hartwell et al. In the figure, reference numeral 3001 denotes a substrate; and 3004, a conductive thin film made of metal oxide formed by sputtering. The conductive thin film 3004 is formed in an H-shaped planar shape as shown. An electron emission portion 3005 is formed by performing an energization process called energization forming described later on the conductive thin film 3004. The interval L in the figure is set at 0.5 to 1 [mm], and W 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. It is not.
[0006]
M. In the above-described surface conduction electron-emitting device including the device by Hartwell et al., It is common to form an electron-emitting portion 3005 by subjecting the conductive thin film 3004 to an energization process called energization forming before performing electron emission. there were. That is, the energization forming means that a constant DC voltage or a DC voltage that increases at a very slow rate of, for example, about 1 V / minute is applied to both ends of the conductive thin film 3004 to energize the conductive thin film 3004. Is locally destroyed, deformed or altered to form an electron emitting portion 3005 in a state of high electrical resistance. 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, electron emission is performed in the vicinity of the crack.
[0007]
Examples of the FE type are described in, for example, W.S. P. Dyke & W. W. Dolan, "Field emission", Advance in Electron Physics, 8, 89 (1956), or C.I. A. Spindt, "Physical Properties of Thin-Film Field Emissions Cathodes with Molybdenium Cones", J. Biol. Appl. Phys. , 47, 5248 (1976).
[0008]
FIG. 22 shows the above-described C.I. A. 1 shows a cross-sectional view of a device by Spindt et al. In the figure, 3010 is a substrate, 3011 is an emitter wiring made of a conductive material, 3012 is an emitter cone, 3013 is an insulating layer, and 3014 is a gate electrode. In this element, by applying an appropriate voltage between the emitter cone 3012 and the gate electrode 3014, field emission is caused from the tip of the emitter cone 3012.
[0009]
Further, as another element configuration 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 a substrate plane, instead of a laminated structure as shown in FIG.
[0010]
FIG. 23 shows a typical example of an MIM-type element configuration (for example, CA Mead, “Operation of tunnel-emission devices, J. Appl. Phys., 32, 646 (1961)). The figure is a cross-sectional view, in which 3020 is a substrate, 3021 is a lower electrode made of metal, 3022 is a thin insulating layer having a thickness of about 100 Å, and 3023 is 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.
[0011]
The above-described cold cathode device can obtain electron emission at a lower temperature than the hot cathode device, and thus does not require a heater for heating. Therefore, the structure is simpler than the hot cathode element, and a fine element can be produced. Further, even when a large number of elements are arranged on a substrate at a high density, problems such as thermal melting of the substrate hardly occur. In addition, unlike the hot cathode element, which operates by heating the heater, the response speed is slow, and the cold cathode element has an advantage that the response speed is fast.
[0012]
For this reason, research for applying the cold cathode device has been actively conducted.
[0013]
For example, the surface conduction electron-emitting device has the advantage of being able to form a large number of devices over a large area because it has a particularly simple structure and is easy to manufacture among cold cathode devices. Therefore, as disclosed in, for example, JP-A-64-31332 by the present applicant, a method for arranging and driving a large number of elements has been studied.
[0014]
As for applications of the surface conduction electron-emitting device, for example, image forming apparatuses such as image display apparatuses and image recording apparatuses, and charged beam sources have been studied.
[0015]
In particular, as an application to an image display device, for example, as disclosed in US Pat. No. 5,066,883, JP-A-2-257551 and JP-A-4-28137 by the present applicant, a surface-conduction emission element is disclosed. An image display device using a combination of a phosphor and a phosphor that emits light when irradiated with an electron beam has been studied. An image display device using a combination of a surface conduction electron-emitting device and a phosphor is expected to have better characteristics than other conventional image display devices. For example, compared to a liquid crystal display device that has become widespread in recent years, it can be said that it is excellent in that it does not require a backlight because it is a self-luminous type and that it has a wide viewing angle.
[0016]
A method of driving a large number of FE types is disclosed in, for example, US Pat. No. 4,904,895 by the present applicant. Further, as an example in which the FE type is applied to an image display device, for example, R.F. The flat panel display reported by Meyer et al. Is known. [R. Meyer: "Recent Development on Microtips Display at LETI", Tech. Digest of 4th Int. Vacuum Microelectronics Conf. , Nagahama, pp. 6-9 (1991)]
An example in which a number of MIM types are arranged and applied to an image display device is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-55738 by the present applicant.
[0017]
[Problems to be solved by the invention]
The inventors have tried cold cathode devices of various materials, manufacturing methods, and structures, including those described in the above prior art. Furthermore, research has been conducted on a multi-electron beam source in which a large number of cold cathode devices are arranged, and on an image display device using the multi-electron beam source.
[0018]
The inventors have tried a multi-electron beam source by, for example, an electrical wiring method shown in FIG. That is, it is a multi-electron beam source in which a large number of cold cathode devices are arranged two-dimensionally 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, and 4003 shows a column direction wiring. Although the row direction wiring 4002 and the column direction wiring 4003 actually have a finite electric resistance, they are shown as wiring resistances 4004 and 4005 in the figure. The above-described wiring method is called simple matrix wiring.
[0019]
For convenience of illustration, the matrix is shown as a 6 × 6 matrix, but the size of the matrix is not limited to this. For example, in the case of a multi-electron beam source for an image display device, a desired image is displayed. Only enough elements are arranged and wired.
[0020]
In a multi-electron beam source in which cold cathode elements are arranged in a simple matrix wiring, an appropriate electric signal is applied to the row wiring 4002 and the column wiring 4003 in order to output a desired electron beam. 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 row direction wiring 4002 is simultaneously applied to the row direction wiring 4002 of the non-selected row. A selection voltage Vns is applied. In synchronization with this, a driving voltage Ve for outputting an electron beam is applied to the column wiring 4003. According to this method, if the voltage drop due to 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 Ve−Vs is applied to the cold cathode elements of the non-selected rows. A voltage of Vns is applied. If Ve, Vs, and Vns are set to voltages of appropriate magnitudes, electron beams of a desired intensity should be output only from the cold cathode elements in the selected row, and a different drive voltage Ve is applied to each of the column wirings. If applied, each of the elements in the selected row should output a different intensity electron beam. In addition, if the length of time during which the drive voltage Ve is applied is changed, the length of time during which the electron beam is output should be changed.
[0021]
Therefore, the multi-electron beam source in which the cold cathode elements are arranged in a simple matrix wiring has various applications. For example, if an electric signal corresponding to image information is appropriately applied, it can be suitably used as an electron source for an image display device. it can.
[0022]
However, a multi-electron beam source in which cold cathode devices are arranged in a simple matrix wiring has actually had the following problems.
[0023]
As described above, in the multi-electron beam source in which the cold cathode elements are arranged in a simple matrix wiring, a row to emit light can be selected by changing a voltage applied to a selected row wiring and a non-selected row wiring. Further, the light emission amount of each element in the selected row can be controlled by changing the magnitude of the driving voltage value applied from each column wiring or the time for applying the driving voltage.
[0024]
In other words, in order to display an image signal having a scanning line structure, the driving voltage application amplitude modulation or the driving voltage application time modulation is performed with the luminance signal of each pixel by associating the number of pixels for one scanning line with the number of column wirings. This can be realized by a so-called line-sequential scanning drive in which voltage is applied to the wiring and the row wiring is sequentially scanned.
[0025]
One of the advantages of line-sequential driving is that, unlike dot-sequential driving performed by a raster scan display device using many CRTs, the selection time of one pixel can be increased. That is, the brightness can be significantly increased, or the acceleration voltage for accelerating the electron beam can be reduced.
[0026]
On the other hand, one of the image signals is a TV signal such as NTSC or HDTV. Normally, a TV signal is intended for a receiver using a CRT, and the gamma characteristic (non-linear characteristic of luminance signal-luminance luminance characteristic) of the CRT is corrected in advance on the transmitting side (hereinafter referred to as gamma correction) and output. Is done.
[0027]
That is, when a display device using a display device other than the CRT, such as the present image display device, receives a TV signal, it is necessary to provide a light emission characteristic conversion unit that matches the nonlinear light emission characteristics of the CRT.
[0028]
Conventionally, for example, in the above-described example, when the column wiring is driven by pulse width modulation that applies a voltage having a pulse width corresponding to the luminance signal intensity in the line sequential driving, the emission electron beam time and the luminance data from the cold cathode element are linear. Therefore, only the light emission characteristic conversion which is called inverse gamma correction for canceling the gamma characteristic of the input TV signal is performed.
[0029]
However, the adoption of line-sequential driving increases the selection time of one pixel. As a result, the light-emitting body (phosphor) of one pixel receives the electron beam irradiation too long. May exhibit a so-called saturation phenomenon that is not proportional to the electron beam irradiation time.
[0030]
The degree of the saturation varies depending on the type of phosphor, electron beam density, electron beam irradiation time, and the like.
[0031]
Due to the saturation phenomenon of the phosphor, the relationship between the luminance signal and the light emission amount may be broken only by the inverse gamma correction of the TV signal. In addition, since the state of saturation changes depending on the type of phosphor, the color balance of the displayed image may be lost in some cases.
[0032]
Alternatively, when the display device receives a plurality of types of input signals such as a TV signal and an image signal of a personal computer (hereinafter, referred to as a PC), the light emission luminance may be changed between when the TV signal is displayed and when the PC signal is displayed. is there. In this case, the color balance of either input signal may be lost.
[0033]
Furthermore, when the display device performs so-called ABL control to reduce the average brightness of the entire screen even if the peak brightness is large in order to suppress power consumption, the color balance of the displayed image may possibly be lost due to the ABL control. There is.
[0034]
Therefore, the present invention considers the light emission characteristics of an image display device, further performs gamma correction on a luminance signal and a color signal according to the type of an input image signal, and faithfully reproduces the color and brightness of an original image signal. Is to be displayed on the screen.
[0035]
[Means for Solving the Problems]
The present invention for solving the above-mentioned problems includes an electron-emitting device, a phosphor that emits light by receiving electrons emitted from the electron-emitting device, and an image signal that converts an input image signal and outputs a converted image signal. Conversion means, and an image display method using an image display device comprising a modulation means for modulating the intensity of the electron beam emitted from the electron-emitting device based on the converted image signal, wherein the image signal conversion means, The input image signal obtained by gamma-correcting the original signal for a cathode ray tube (CRT) is restored to the original signal, and the restored original signal is corrected by correcting the nonlinearity of the electron beam intensity versus the phosphor emission luminance. The image signal is converted into the converted image signal which makes the light emission luminance characteristic of the phosphor be linear with respect to the beam intensity and output.
According to the present invention, there is provided an electron-emitting device connected to a row wiring and a column wiring arranged in a matrix, a phosphor that emits light by receiving electrons emitted from the electron-emitting device, and an input image signal. An image display device comprising: image signal conversion means for converting and outputting a converted image signal; and modulation means for modulating an electron beam emitted from the electron-emitting device based on the converted image signal. The signal conversion means restores the input image signal obtained by gamma-correcting the original signal for a cathode ray tube to the original signal, and corrects the restored original signal to correct the nonlinearity of the electron beam intensity versus the phosphor emission luminance. The modulation means converts the electron beam intensity versus the phosphor emission luminance characteristic into a straight line and outputs the converted image signal. The modulating means outputs an electric signal applied to the column wiring based on the converted image signal. Characterized by modulating the pulse width.
According to the present invention, there is provided an electron-emitting device connected to a row wiring and a column wiring arranged in a matrix, a phosphor that emits light by receiving electrons emitted from the electron-emitting device, and an input image signal. An image display device comprising: image signal conversion means for converting and outputting a converted image signal; and modulation means for modulating an irradiation time of an electron beam emitted from the electron-emitting device based on the converted image signal. The image signal converting means restores the input image signal obtained by gamma-correcting the original signal for a cathode ray tube to the original signal, and restores the restored original signal to the nonlinearity of the original signal versus the phosphor emission amount. The conversion means converts the converted image signal to the converted image signal which makes the phosphor emission amount characteristic a straight line, and outputs the converted image signal. The modulating means outputs an electric signal applied to the column wiring based on the converted image signal. Characterized by modulating the pulse width.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
The first embodiment is directed to a display panel having a multi-electron beam source in which a plurality of surface conduction elements are arranged in a matrix with a plurality of row wirings and column wirings, and a phosphor screen which emits light by receiving electron beam irradiation from each electron beam source ( An example in which a TV signal is displayed on an SED panel will be described.
[0037]
FIG. 1 shows a block diagram of a drive circuit of the SED panel.
[0038]
Reference numeral P2000 denotes a display panel. In this embodiment, 240 * 720 surface conduction elements P2001 are matrix-wired by 240 vertical rows and 720 horizontal columns, and emission from each surface conduction element P2001 is performed. The electron beam is accelerated by a high-voltage applied from the high-voltage power supply unit P30 and is irradiated with a phosphor (not shown) to emit light. The phosphor (not shown) can have various color arrangements depending on the application. For example, an RGB vertical stripe color arrangement is used.
[0039]
In the present embodiment, an application example of displaying a television image equivalent to NTSC on a display panel having 240 pixels (horizontal trio) * 240 pixels vertically will be described below. It is possible to easily cope with image signals having different resolutions and frame rates, such as images and output images of a computer, with almost the same configuration.
[0040]
FIG. 2 shows an NTSC-RGB decoder unit P1 that receives an NTSC composite video input and outputs RGB components. In this unit, a synchronization signal (SYNC) superimposed on the input video signal is separated and output. Similarly, a color burst signal superimposed on the input video signal is separated, and a CLK signal (CLK1) synchronized with the color burst signal is generated and output.
[0041]
FIG. 3 shows a timing generator P2 for generating the following timing signals required to convert the analog RGB signals decoded at P1 into digital gradation signals for luminance-modulating the SED panel. . The signal output from the timing generation unit P2 includes a clamp pulse for DC reproduction of the RGB analog signal from P1 in the analog processing unit P3 and a blank period added to the RGB analog signal from P1 in the analog processing unit P3. Pulse, a detection pulse for detecting the level of the RGB analog signal in the video detection unit P4, and a conversion signal for converting the analog RGB signal into a digital signal in the A / D unit P6. A sample pulse (not shown), a RAM controller control signal necessary for the RAM controller P12 to control the RAMP8, and a free-running CLK signal (CLK2) generated in P2 and synchronized with CLK1 by the PLL circuit in P2 when CLK1 is input. And a synchronization signal (SYNC2) generated based on CLK2 in P2. .
[0042]
Since the timing generating section P2 includes the free-running CLK2 generating means, it can generate the reference signals CLK2 and SYNC2 even when there is no input video signal, so that the image display is performed by reading the image data of the RAM means P8. it can.
[0043]
FIG. 4 shows an analog processing section P3 provided for each output primary color signal from P1. The analog processing unit P3 receives a clamp pulse from P2 and performs DC regeneration. In addition, a blanking period is added by receiving a BLK pulse from P2.
[0044]
Also, it receives the gain adjustment signal of the D / A unit P14, which is one of the control outputs of the system control unit mainly composed of the MPUP 11, and controls the amplitude of the primary color signal input from P1.
[0045]
Further, it receives an offset adjustment signal of the D / A section P14, which is one of the control outputs of the system control section mainly composed of the MPUP 11, and performs black level control of the primary color signal input from P1.
[0046]
P4 is a video detection unit for detecting an input video signal level or a video signal level after being controlled by the analog processing unit P3, receives a detection pulse from P2, and is configured around the MPUP11. The detection result is read by the A / D unit P15 which is one of the control inputs of the system control unit.
[0047]
The detection pulse from P2 includes, for example, a gate pulse, a reset pulse, and a sample and hold (S / H) pulse, and the video detection unit includes, for example, an integrating circuit and an S / H circuit.
[0048]
For example, during the valid period of the input video signal by the gate pulse, the video signal is integrated by the above-mentioned integration circuit, and the output of the integration circuit is sampled by the S / H circuit by the S / H pulse generated in the vertical flyback period. After the detection result is read by the A / D unit P15 during the vertical flyback period, the reset circuit initializes the integration circuit and the S / H circuit.
[0049]
With such an operation, the average video level for each field can be detected.
[0050]
The LPFP 5 is a pre-filter unit placed before the A / D unit P6.
[0051]
The A / D unit P6 is an A / D converter that receives the sample CLK from P2 and quantizes the analog primary color signal that has passed through the LPFP 5 with a required number of gradations.
[0052]
The conversion table P7 is a gradation characteristic conversion means provided for converting an input video signal into light emission characteristics of the display panel. When a luminance gradation is expressed by pulse width modulation as in the present embodiment, a linear characteristic in which the amount of light emission is almost proportional to the size of luminance data is often exhibited. On the other hand, since the video signal is intended for a TV receiver using a CRT, the video signal is subjected to gamma processing in order to correct the nonlinear light emission characteristics of the CRT. Therefore, when a TV image is displayed on a panel having linear light emission characteristics as in the present embodiment, it is necessary to cancel the effect of the gamma processing by the gradation characteristic conversion means such as P7.
[0053]
The table data can be switched by the output of the I / O control unit P13, which is one of the control inputs and outputs of the system control unit mainly composed of the MPUP 11, and the light emission characteristics can be changed as desired.
[0054]
P8 is an image memory provided for each R / G / B processing circuit and has addresses corresponding to the total number of display pixels of the panel (in this case, 240 horizontal * 240 vertical * 3). The luminance data to be emitted by each pixel of the panel is stored in this memory, and the luminance data is read out in a dot-sequential manner, whereby the image stored in the memory is displayed on the panel.
[0055]
The output of the luminance data from P8 is performed under the address control from the RAM controller P12.
[0056]
The writing of data to P8 is performed under the management of a system control unit mainly composed of MPUP11. In the case of a simple test pattern or the like, the MPUP 11 calculates and generates and writes luminance data stored in each address of P8. In the case of a pattern such as a natural still image, for example, an image file stored in an external computer or the like is read via a serial communication I / FP 16 which is one of input / output units of a system control unit mainly composed of an MPUP 11, and is read. Write to the memory P8.
[0057]
Reference numeral P9 denotes a data selector, which is a system control unit mainly constituted by the MPUP 11, which determines whether to output the image data from the image memory P8 or the data from the A / D unit P6 (input video signal system). Is determined by the output of the I / O control unit P13, which is one of the control input / outputs.
[0058]
In addition to the input selection of these two systems, there is a mode in which a fixed value is generated from P9, and this mode can be selected and output by P13. In this mode, for example, an adjustment signal such as an all-white pattern can be displayed at high speed without an external input.
[0059]
P10 is a horizontal one-line memory means provided for each primary color signal, and rearranges the luminance data input in three parallel RGB systems in an order according to the panel color arrangement according to a control signal of the line memory control unit P21. And outputs the signal to the X driver via the latch means P22.
[0060]
The system control section mainly includes an MPUP 11, a serial communication I / FP 16, an I / O control section P13, a D / A section P14, an A / D section P15, a data memory P17, and a user SW means P18.
[0061]
The system control unit receives a user request from the user SW means P18 and the serial communication I / FP 16, and realizes the request by outputting a corresponding control signal from the I / O control unit P13 and the D / A unit P14.
[0062]
Also, optimal automatic control is performed by receiving a system monitoring signal from the A / D unit P15 and outputting a corresponding control signal from the I / O control unit P13 and the D / A unit P14.
[0063]
In the present embodiment, as a user request, display control such as test pattern generation, variable gradation, brightness, and color control can be realized. As described above, the A / D section P15 can monitor the average video level from the video detection section P4 to perform automatic control such as ABL.
[0064]
Further, by providing the data memory P17, the user adjustment amount can be stored.
[0065]
P19 is a Y driver control timing generator, and P20 is an X driver control timing generator, which receives the CLK1, CLK2 and SYNC2 signals and generates Y driver control and X driver control signals.
[0066]
A control unit P21 controls the timing of the line memory P10. The control unit receives the CLK1, CLK2, and SYNC2 signals, and writes R, G, and B WRT control signals for writing luminance data to the line memory. R, G, and B RD control signals for reading luminance data in a corresponding order are generated.
[0067]
FIG. 5 is a time chart for explaining the operation of the SED drive circuit.
[0068]
T104 is a waveform of a color sample data string written by taking one of the RGB colors as an example, and is composed of 240 data strings in one horizontal period. This data string is written into the line memory P10 by the control signal in one horizontal period. In the next horizontal period, the line memory P10 for each color is read out and enabled at a frequency three times as high as that in the case of writing, thereby obtaining 720 luminance data strings per one horizontal period such as T105.
[0069]
P1001 is an X, Y driver timing generator, which receives control signals from the Y driver control timing generator P19 and the X driver control timing generator P20. The signal output from P1001 is used for fetching the shift clock and the data read into the shift registers P1101 and 1107 to a memory unit (not shown) in the PWM generator unit P1102 and the D / A unit P1103, and the PWM generator unit P1102. An LD pulse acting as a horizontal cycle trigger to the D / A unit P1103, an If table ROM control signal, a horizontal cycle shift clock for moving the Y shift register for Y driver control, and a row scanning start trigger are provided. Signal of the vertical cycle for the trigger.
[0070]
The shift register P1101 reads the luminance data string of 720 column wirings per horizontal cycle from the latch means P22 by a shift clock synchronized with the luminance data from the X, Y driver timing generator P1001 as shown in FIG. The data of 720 horizontal rows is transferred to the PWM generator unit P1102 at once by an LD pulse such as T108.
[0071]
The shift register P1107 reads the column wiring drive current data string of 720 column wirings per horizontal cycle from the data selector means P1201 by the shift clock in the same manner as the luminance data, and the D / A unit P1103 by the LD pulse such as T108. , The data for 720 horizontal rows is transferred at one time.
[0072]
An If table ROM P1202 is a memory means for storing data of a current amplitude value to be passed through each of the 720 * 240 surface conduction type elements of the display panel P2000, and an If table ROM from the X, Y driver timing generator P1001. Under the read address control by the control signal, data of 720 current amplitude values of one row to be scanned as shown in FIG.
[0073]
By setting the current value for driving the column wiring (that is, the surface conduction type element) to an optimum value for each element using the If table ROMP1202, the uniformity of luminance can be extremely improved.
[0074]
Further, the If table ROMP 1202 may include 720 * 240 current amplitude value data as one bank and include a plurality of types of banks. For example, when the light emission luminance of the panel is switched in a plurality of stages, current amplitude data to be passed to each element is stored in a bank corresponding to each stage, and one of the control input / outputs of a system control unit mainly composed of the MPUP11. , The If data bank corresponding to the desired brightness can be selected by a bank switching signal output from the I / O control unit P13.
[0075]
A data selector means P1201 is provided for the case where the If table ROM P1202 is not used for the purpose of cost reduction or the like, and the I / O which is one of the control inputs / outputs of the system control unit mainly composed of the MPUP11 is provided. The If setting data output from the control unit P13 can be output to the shift register P1107 by a switching signal from the I / O control unit P13. This makes it possible to control the display brightness of the panel by changing the output If data.
[0076]
The PWM generator unit P1102 provided for each column wiring receives the luminance data from the shift register P1101, and generates a pulse signal having a pulse width proportional to the data size for each horizontal cycle as shown in the waveform of T110 in FIG. .
[0077]
A D / A unit P1103 provided for each column wiring is a current-output digital-to-analog converter which receives current amplitude value data from the shift register P1107, and has a data size for each horizontal cycle as shown in a waveform T111 in FIG. A drive current having a current amplitude proportional to the drive current is generated.
[0078]
P1104 is a switch means composed of a transistor or the like, and applies a current output from the D / A unit P1103 to the column wiring while the output from the PWM generator unit P1102 is valid, and disables an output from the PWM generator unit P1102. During the period, the column wiring is grounded. FIG. 2T111 shows an example of a column wiring drive waveform.
[0079]
The diode side P1105 provided for each column wiring has a common side connected to the Vmax regulator P1106. The Vmax regulator P1106 is a constant voltage source capable of sinking current and forms a protection circuit for preventing overvoltage from being applied to each of the 720 * 240 surface conduction type elements of the display panel P2000 together with the diode means P1105. .
[0080]
This protection voltage (the potential defined by Vmax and −Vss applied when scanning the row wiring is selected) is given by the D / A unit P14, which is one of the control inputs and outputs of the system control unit mainly composed of the MPUP11. Can be
[0081]
Therefore, it is possible to change the Vmax potential (or -Vss potential) for the purpose of luminance control, in addition to preventing element overvoltage.
[0082]
That is, if the If data that increases the output current of the D / A section P14 is given and the protection diode means P1105 is always set to conduct, the selection potential of the surface conduction element P2001 becomes (Vmax + Vss). , Vmax potential (or -Vss potential), luminance control can be realized.
[0083]
The Y shift register unit P1002 receives a horizontal cycle shift clock from the X, Y driver timing generator and a vertical cycle trigger signal for giving a row scanning start trigger, and outputs a selection signal for scanning the row wiring to each row. The signals are sequentially output to a pre-driver unit P1003 provided for each wiring.
[0084]
An output unit for driving each row wiring is composed of, for example, transistor means P1006, FET means P1004, and diode means P1007. The pre-driver section P1003 drives this output section with good response. The FET unit P1004 is a switch unit that is turned on when a row is selected, and applies the -Vss potential from the constant voltage regulator unit P1005 to the row wiring at the time of selection. The transistor means P1006 is a switch means which conducts when a row is not selected, and applies the Vso potential from the constant voltage regulator unit P1005 to the row wiring when the row is not selected. FIG. 2T112 shows an example of the row wiring drive waveform.
[0085]
The diode means P1007 is provided for preventing an abnormal potential from being generated in the row wiring and protecting the output unit for driving each row wiring. The constant voltage regulator units P1005 and 1008 that generate the -Vss and Vso potentials are controlled by a D / A unit P14, which is one of the control inputs and outputs of a system control unit mainly composed of the MPUP11.
[0086]
Similarly, the high-voltage power supply unit P30 is also controlled by a D / A unit P14, which is one of the control inputs and outputs of the system control unit mainly composed of the MPUP11.
[0087]
In the above configuration, the present embodiment calculates correction data to be stored in the conversion table P7 as follows.
[0088]
When the luminance data is x1 (x is an integer from 0 to (2 n -1) when the number of gradations is n bits), the conversion characteristic of the gamma correction performed on the TV signal transmission side is f1 (x1), and f1 ( The inverse function of x1) is g1 (x1).
[0089]
When the pulse width modulation data is x2, the non-linear characteristic curve of the luminance-pulse width data of the SED panel is f2 (x2), and the inverse function of f2 (x2) is g2 (x2), the TV signal transmitting side is used first. X1 ′ is calculated to cancel the gamma correction.
[0090]
x1 ′ = (g1 (x1) / g1 (x1max)) × (x1) (conversion formula 1)
Next, x2 'is calculated to cancel the nonlinear characteristic curve of the luminance-pulse width data possessed by the SED panel.
[0091]
x2 ′ = (g2 (x2) / g2 (x2max)) × (x2) (conversion formula 2)
X2 'obtained by substituting x1' obtained by the conversion formula 1 into x2 of the conversion formula 2 is approximated to an integer value, and a table P7 for outputting x2 'with respect to the input x is created.
(The address signal in the table ROM (P7) is made to correspond to x, and x2 'is stored in the memory corresponding to that address).
[0092]
More specifically, it may be performed as follows.
[0093]
FIG. 6 shows an example of a gamma correction conversion curve performed on the TV signal transmission side to correct the gamma characteristic of the CRT. According to the literature (edited by Japan Broadcasting Corporation, page 47 of Hi-Vision technology), an approximate curve of γ = 0.45 is often used. Accordingly, an approximate curve of γ = 2.2 may be used as a function for the inverse γ correction (corresponding to the above g (x1)).
[0094]
FIG. 7 shows normalized luminance-gradation data (almost proportional to the drive voltage pulse width) of the SED panel used in the present embodiment. By calculating the inverse function of the approximation function of the upwardly convex curve, the nonlinearity of the SED panel can be corrected as in the case of the inverse gamma correction.
[0095]
As can be seen from FIG. 7, the nonlinearity of the SED panel differs depending on the RGB phosphor. By calculating the inverse function of the approximation function of the convex curve for each color, it is possible to correct the nonlinear difference for each color.
[0096]
In this example, the emission characteristic of R can be approximated by γ = 0.72, the emission characteristic of G can be approximated by γ = 0.9, and the emission characteristic of B can be approximated by γ = 1. Since this value may change depending on the driving condition of the panel, the above is only an example, and it is necessary to calculate the value according to the driving condition of the panel.
[0097]
The method of creating table data by the power function approximation has been described above. However, the present invention is not limited to this, and another function approximation or an actual measured curve of panel characteristics may be used.
[Second embodiment]
The second embodiment of the present invention will be described with an example in which the display device having the configuration shown in FIG. 1 can further receive an HDTV signal and a computer signal in addition to the NTSC signal.
[0098]
That is, the second embodiment has a configuration having an input signal switching unit as shown in FIG.
[0099]
P40, P41, and P42 are interface units corresponding to NTSC signals, HDTV signals, and computer signals. Each of the interface units converts the resolution of an input signal so as to match the number of pixels of the display panel P2000, and outputs RGB component signals and SYNC signals. .
[0100]
P44 is a signal switching unit such as a remote controller accessed by the user, and sends a selection signal indicating which input signal is to be displayed to the signal determination unit P45.
[0101]
P45 is a signal discrimination unit that receives a selection signal from P44 and supplies a switching signal to the signal selector unit P43.
[0102]
The signal discriminating section P45 receives a status signal from each of the I / F sections P40 to P42. For example, when only one type of signal is input, the signal selecting section P43 sends a switching signal to the signal selector section P43 so as to automatically display the signal. give.
[0103]
P43 is a signal selector, which selects and outputs one of three types of input signals according to the switching signal from the signal discriminator P45.
[0104]
Further, the signal discriminating section P45 gives information on which signal is currently selected to the system control section mainly constituted by the MPUP 11 in FIG.
[0105]
The system control unit can determine the type of the image signal to be received at present based on this information.
[0106]
For example, when displaying a TV signal such as an NTSC signal or an HDTV signal, it is desirable to have a high luminance for viewing away from the display screen, and when displaying a PC signal, it is desirable to reduce the luminance for viewing near the display screen.
[0107]
At this time, the system control unit performs luminance control using the luminance control method (controls If data, Vmax, -Vss, and the like) described in the first embodiment according to the type of input to be received. .
[0108]
Under the brightness control, the non-linearity of the normalized brightness-gradation data of the SED panel may change (the higher the light emission brightness, the stronger the upward convexity). Therefore, by switching to the conversion table P7 corresponding to the type of the image signal at the same time as the luminance control according to the input signal, a suitable display image can be obtained regardless of the input signal.
[Third Embodiment]
In the third embodiment of the present invention, in the display device having the configuration shown in FIG. 1, the average luminance level of the input image signal is detected in order to suppress the power consumption of the entire device. An example in which the so-called ABL control is performed will be described.
[0109]
In the operation described in the first embodiment, the average input luminance level for each color is detected in an analog amount by the video detection unit P4 provided for each of RGB, and the digital value is detected by the A / D converter of the system control unit in P15. Is read into the system control section. The MPUP 11 of the system control unit monitors, for example, the average input luminance level for each field period, and when the average input luminance level exceeds a certain threshold value, the luminance control method (If data or the like) described in the first embodiment. Vmax, −Vss, etc.) is used to perform luminance control. The higher the average input luminance level is, the stronger the luminance suppression control is made so that the average light emission luminance over the entire panel does not exceed a certain threshold.
[0110]
In the third embodiment, the conversion table P7 is switched in conjunction with the brightness control that is performed when the average input brightness level exceeds a certain threshold.
[0111]
That is, when the average input luminance level is low and the luminance suppression control does not work, the density of the electron beam irradiating the phosphor is high, and the light emission amount becomes more saturated as the luminance data increases. At this time, a conversion table for low average input luminance level in which a large saturation characteristic is corrected in addition to the inverse gamma correction is selected.
[0112]
In addition, when the average input luminance level is high and the luminance suppression control works strongly, the electron beam density for irradiating the phosphor decreases, and the saturation characteristics based on the luminance data of the light emission amount decrease. At this time, a conversion table for high average input luminance level in which small saturation characteristics are corrected in addition to the inverse gamma correction is selected.
[0113]
In this way, a conversion table is prepared which is divided into a plurality of stages from the low average input luminance level to the high average input luminance level, and in addition to the inverse gamma correction, a conversion table in which a saturation characteristic representing that stage is corrected is prepared. , A suitable display image can be obtained.
(Display panel configuration and manufacturing method)
Next, the configuration and manufacturing method of the display panel of the image display device to which the present invention is applied will be described with reference to specific examples.
[0114]
FIG. 9 is a perspective view of the display panel used in the embodiment, in which a part of the panel is cut away to show the internal structure.
[0115]
In the figure, 1005 is a rear plate, 1006 is a side wall, 1007 is a face plate, and 1005 to 1007 form an airtight container for maintaining the inside of the display panel in a vacuum. When assembling the airtight container, it is necessary to seal the joints of the members to maintain sufficient strength airtightness.For example, apply frit glass to the joints, Sealing was achieved by baking at 400 to 500 degrees for 10 minutes or more. A method for evacuating the inside of the airtight container will be described later.
[0116]
A substrate 1001 is fixed to the rear plate 1005, and N × M cold cathode elements 1002 are formed on the substrate (N and M are positive integers of 2 or more, and For example, in a display device for displaying high-definition television, it is desirable to set N = 3000 and M = 1000 or more. , N = 3072, 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. The portion constituted by 1001 to 1004 is called a multi-electron beam source. The manufacturing method and structure of the multi-electron beam source will be described later in detail.
[0117]
In the present embodiment, the substrate 1001 of the multi-electron beam source is fixed to the rear plate 1005 of the hermetic container. However, if the substrate 1001 of the multi-electron beam source has a sufficient strength, the hermetic container is used. The substrate 1001 of the multi-electron beam source itself may be used as the rear plate.
[0118]
A fluorescent film 1008 is formed on the lower surface of the face plate 1007. Since the present embodiment is a color display device, phosphors of three primary colors of red, green, and blue used in the field of CRT are separately applied to a portion of the fluorescent film 1008. The phosphor of each color is separately applied in a stripe shape as shown in FIG. 10A, for example, and a black conductor 1010 is provided between the stripes of the phosphor. The purpose of providing the black conductor 1010 is to prevent the display color from being shifted even when the irradiation position of the electron beam is slightly shifted, and to prevent the reflection of external light to prevent the reduction of the display contrast. And preventing charge-up of the fluorescent film by the electron beam. Although graphite is used as a main component for the black conductor 1010, any other material may be used as long as it is suitable for the above purpose.
[0119]
Further, the method of applying the phosphors of the three primary colors is not limited to the stripe arrangement shown in FIG. 22A, but may be, for example, a delta arrangement as shown in FIG. It may be an array.
[0120]
When a monochrome display panel is manufactured, a single-color phosphor material may be used for the fluorescent film 1008, and a black conductive material is not necessarily used.
[0121]
A metal back 1009 known in the field of CRTs is provided on the surface of the fluorescent film 1008 on the rear plate side. The purpose of providing the metal back 1009 is to improve the light utilization rate by mirror-reflecting a part of the light emitted from the fluorescent film 1008, to protect the fluorescent film 1008 from the collision of negative ions, and to increase the electron beam acceleration voltage. , Or as a conductive path for excited electrons in the fluorescent film 1008. The metal back 1009 was formed by forming a fluorescent film 1008 on the face plate substrate 1007, smoothing the surface of the fluorescent film, and vacuum-depositing Al thereon. Note that when a phosphor material for low voltage is used for the fluorescent film 1008, the metal back 1009 is not used.
[0122]
Although not used in this embodiment, a transparent electrode made of, for example, ITO is provided between the face plate substrate 1007 and the fluorescent film 1008 for the purpose of applying an acceleration voltage and improving the conductivity of the fluorescent film. You may.
[0123]
Dx1 to Dxm, Dy1 to Dyn, and Hv are electric connection terminals having an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown). Dx1 to Dxm are electrically connected to the row wiring 1003 of the multi-electron beam source, Dy1 to Dyn are electrically connected to the column wiring 1004 of the multi-electron beam source, and Hv is electrically connected to the metal back 1009 of the face plate.
[0124]
In order to evacuate the inside of the hermetic container to a vacuum, after assembling the hermetic container, an exhaust pipe (not shown) is connected to a vacuum pump, and the inside of the hermetic container is evacuated to a degree of vacuum of about 10 −7 [Torr]. Exhaust. Thereafter, the exhaust pipe is sealed, but a getter film (not shown) is formed at a predetermined position in the airtight container immediately before or after the sealing in order to maintain the degree of vacuum in the airtight container. The getter film is, for example, a film formed by heating and depositing a getter material containing Ba as a main component by a heater or high-frequency heating, and the inside of the hermetic container is 1 × 10 −5 or 1 due to the adsorbing action of the getter film. The degree of vacuum is maintained at × 10−7 [Torr].
[0125]
The basic configuration and manufacturing method of the display panel according to the embodiment of the present invention have been described above.
[0126]
Next, a method for manufacturing the multi-electron beam source used for the display panel of the embodiment will be described. The material, shape, and manufacturing method of the cold cathode device are not limited as long as the multi-electron beam source used in the image display device of the present invention is an electron source in which cold cathode devices are arranged in a simple matrix. Therefore, for example, a cold cathode device such as a surface conduction type emission device, an FE type, or an MIM type can be used.
[0127]
However, in a situation where a display device having a large display screen and an inexpensive display device is required, among these cold cathode devices, the surface conduction type emission device is particularly preferable. That is, in the FE type, since the relative position and shape of the emitter cone and the gate electrode greatly affect the electron emission characteristics, extremely high-precision manufacturing technology is required, but this achieves a large area and a reduction in manufacturing cost. Is a disadvantageous factor. Further, in the MIM type, it is necessary to make the thicknesses of the insulating layer and the upper electrode thin and uniform, which is also a disadvantageous factor in achieving a large area and a reduction in manufacturing cost. On the other hand, since the surface conduction electron-emitting device has a relatively simple manufacturing method, it is easy to increase the area and reduce the manufacturing cost. The inventors have found that among the surface conduction electron-emitting devices, those in which the electron-emitting portion or its peripheral portion is formed of a fine particle film have particularly excellent electron-emitting characteristics and can be easily manufactured. Therefore, it can be said that it is most suitable for use in a multi-electron beam source of a high-luminance, large-screen image display device. Therefore, in the display panel of the above embodiment, a surface conduction electron-emitting device in which the electron-emitting portion or its peripheral portion is formed of a fine particle film is used. Therefore, the basic configuration, manufacturing method, and characteristics of a suitable surface conduction electron-emitting device will be described first, and then the structure of a multi-electron beam source in which many devices are arranged in a simple matrix will be described.
(Suitable device structure and manufacturing method of surface conduction type emission device)
There are two typical configurations of a surface conduction electron-emitting device in which an electron-emitting portion or its peripheral portion is formed from a fine particle film, a planar type and a vertical type.
(Flat-type surface conduction electron-emitting device)
First, an element configuration and a manufacturing method of the planar type surface conduction electron-emitting device will be described.
[0128]
FIG. 11 shows a plan view (a) and a cross-sectional view (b) for explaining the configuration of a planar surface conduction electron-emitting device. In the figure, 1101 is a substrate, 1102 and 1103 are device electrodes, 1104 is a conductive thin film, 1105 is an electron-emitting portion formed by energization forming, and 1113 is a thin film formed by energization activation.
[0129]
As the substrate 1101, for example, various glass substrates such as quartz glass and blue plate glass, various ceramics substrates including alumina, or SiO.sub.₂A substrate on which an insulating layer made of a material is laminated can be used.
[0130]
The device electrodes 1102 and 1103 provided on the substrate 1101 in parallel with the substrate surface are formed of a conductive material. For example, metals including Ni, Cr, Au, Mo, W, Pt, Ti, Cu, Pd, Ag, etc., alloys of these metals, or In₂O₃-SnO₂And other materials such as metal oxides and semiconductors such as polysilicon. An electrode 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 electrode can be formed by other methods (for example, printing technique). I can't wait.
[0131]
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 spacing L is usually designed by selecting an appropriate value from the range of several hundreds of angstroms to several hundreds of micrometers. Among them, for application to a display device, it is preferable that the electrode spacing L be more than a few micrometers. It is in the range of ten micrometers. Further, as for the thickness d of the device electrode, an appropriate numerical value is usually selected from the range of several hundred angstroms to several micrometers.
[0132]
A fine particle film is used for the conductive thin film 1104. The fine particle film described here refers to a film containing a large number of fine particles as constituent elements (including an island-shaped aggregate). When the fine particle film is examined microscopically, usually, a structure in which the individual fine particles are spaced apart from each other, a structure in which the fine particles are adjacent to each other, or a structure in which the fine particles overlap each other is observed.
[0133]
The particle size of the fine particles used for the fine particle film is in the range of several Angstroms to several thousand Angstroms, but is preferably in the range of 10 Angstroms to 200 Angstroms. The thickness of the fine particle film is appropriately set in consideration of various conditions as described below. That is, the conditions necessary for good electrical connection to the element electrode 1102 or 1103, the conditions necessary for good energization forming described below, and the electric resistance of the fine particle film itself to an appropriate value described later. Necessary conditions, etc. Specifically, it is set within the range of several Angstroms to several thousand Angstroms, and the most preferable is between 10 Angstroms and 500 Angstroms.
[0134]
Materials that can be used to form the fine particle film include, for example, Pd, Pt, Ru, Ag, Au, Ti, In, Cn, Cr, Fe, Zn, Sn, Ta, W, and Pb. Metal, PdO, SnO₂, In₂O₃, PbO, Sb₂O₃Such as oxides, borides such as HfB2, ZrB2, LaB6, CeB6, YB4, and GdB4; carbides such as TiC, ZrC, HfC, TaC, SiC, WC; Examples include nitrides such as ZrN and HfN, semiconductors such as Si and Ge, carbon, and the like, and are appropriately selected from these.
[0135]
As described above, the conductive thin film 1104 is formed of a fine particle film, and its sheet resistance is set to be in the range of 10 3 to 10 7 [Ohm / sq].
[0136]
Note that the conductive thin film 1104 and the device electrodes 1102 and 1103 are desirably electrically connected favorably, and thus have a structure in which a part of each overlaps. In the example of FIG. 23, the overlapping manner is such that the substrate, the device electrode, and the conductive thin film are stacked in this order from the bottom. I can't wait.
[0137]
Further, the electron emitting portion 1105 is a crack-like portion formed in a part of the conductive thin film 1104, and has a higher electrical property than the surrounding conductive thin film. The crack is formed by performing the energization forming process described later 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, it is shown in a film form in FIG.
[0138]
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.
[0139]
The thin film 1113 is any one of single-crystal graphite, polycrystalline graphite, and amorphous carbon or a mixture thereof, and has a thickness of 500 Å or less, more preferably 300 Å or less. .
[0140]
Since it is difficult to accurately show the actual position and shape of the thin film 1113, it is schematically shown in FIG. Further, in the plan view (a), an element in which a part of the thin film 1113 is removed is illustrated.
[0141]
The basic configuration of the preferred device has been described above. In the embodiment, the following device is used.
[0142]
That is, blue glass was used for the substrate 1101, and Ni thin films were used for the device electrodes 1102 and 1103. The thickness d of the device electrode was 1000 [angstrom], and the electrode interval L was 2 [micrometer].
[0143]
Pd or PdO was used as the main material of the fine particle film, the thickness of the fine particle film was about 100 [angstrom], and the width W was 100 [micrometer].
[0144]
Next, a method for manufacturing a suitable planar surface conduction electron-emitting device will be described.
[0145]
12A to 12D are cross-sectional views for explaining a manufacturing process of the surface conduction electron-emitting device, and the notation of each member is the same as that in FIG.
[0146]
1) First, as shown in FIG. 12A, device electrodes 1102 and 1103 are formed on a substrate 1101.
[0147]
In formation, the substrate 1101 is sufficiently washed in advance with a detergent, pure water, and an organic solvent, and then a material for an element electrode is deposited (for example, a vacuum deposition method such as a vapor deposition method or a sputtering method). Technology 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.
[0148]
2) Next, a conductive thin film 1104 is formed as shown in FIG.
[0149]
In the formation, first, an organic metal solution is applied to the substrate (a), dried, heated and baked to form a fine particle film, and then patterned into a predetermined shape by photolithography and etching. Here, the organic metal solution is a solution of an organic metal compound having a material of fine particles used for the conductive thin film as a main element (specifically, Pd is used as a main element in the present embodiment. In the embodiment, a dipping method is used as a coating method, but other methods such as a spinner method and a spray method may be used.)
[0150]
In addition, as a method for forming a conductive thin film made of a fine particle film, other than the method of applying the organometallic solution used in the present embodiment, for example, a vacuum evaporation method, a sputtering method, or a chemical vapor deposition method may be used. Sometimes used.
[0151]
3) Next, as shown in FIG. 3C, an appropriate voltage is applied between the device electrodes 1102 and 1103 from the forming power supply 1110, and the energization forming process is performed to form the electron emission portion 1105.
[0152]
The energization forming process is a process of energizing the conductive thin film 1104 made of a fine particle film to appropriately break, deform, or alter a part of the conductive thin film 1104 to change the structure to a structure suitable for electron emission. That is. In 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 1105), an appropriate crack is formed in the thin film. Note that the electrical resistance measured between the device electrodes 1102 and 1103 is significantly increased after the formation of the electron emission portions 1105 as compared to before the formation.
[0153]
FIG. 13 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 pulsed voltage is preferable. In the case of this embodiment, a triangular wave pulse having a pulse width T1 is continuously generated at a pulse interval T2 as shown in FIG. Was applied. At that time, the peak value Vpf of the triangular wave pulse was sequentially increased. In addition, a monitor pulse Pm for monitoring the state of formation of the electron-emitting portion 1105 was inserted between triangular-wave pulses at appropriate intervals, and the current flowing at that time was measured by an ammeter 1111.
[0154]
In the embodiment, for example, in a vacuum atmosphere of about 10 −5 [Torr], for example, the pulse width T1 is 1 [millisecond], the pulse interval T2 is 10 [millisecond], and the peak value Vpf is every pulse. Was increased by 0.1 [V]. Then, the monitor pulse Pm was inserted at a rate of one every time five triangular waves were applied. The monitor pulse voltage Vpm was set to 0.1 [V] so as not to adversely affect the forming process. Then, when the electric resistance between the element electrodes 1102 and 1103 becomes 1 × 10 6 [ohm], that is, the current measured by the ammeter 1111 when a monitor pulse is applied is 1 × 10 −7 [A]. When the following conditions were reached, the energization related to the forming process was terminated.
[0155]
The above method is a preferable method for the surface conduction electron-emitting device of the present embodiment. For example, when the design of the surface conduction electron-emitting device such as the material and thickness of the fine particle film or the device electrode interval L is changed. It is desirable to appropriately change the energization conditions accordingly.
[0156]
4) Next, as shown in FIG. 12 (d), an appropriate voltage is applied between the element electrodes 1102 and 1103 from the activation power supply 1112, and an energization activation process is performed to improve the electron emission characteristics. Do.
[0157]
The energization activation process is a process of energizing the electron-emitting portion 1105 formed by the energization forming process under appropriate conditions and depositing carbon or a carbon compound in the vicinity thereof (in FIG. Alternatively, a deposit made of 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 as compared with before the energization activation process.
[0158]
Specifically, by periodically applying a voltage pulse in a vacuum atmosphere within a range of 10 −4 to 10 −5 [Torr], the organic compound existing in the vacuum atmosphere can be generated. Depositing carbon or carbon compounds. The deposit 1113 is any one of single crystal graphite, polycrystal graphite, and amorphous carbon, or a mixture thereof, and has a thickness of 500 Å or less, more preferably 300 Å or less.
[0159]
FIG. 14A 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 having a constant voltage. Specifically, the voltage Vac of the rectangular wave is 14 [V], and the pulse width T3 is 1 [mm]. Second] and the pulse interval T4 is 10 [milliseconds]. Note 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.
[0160]
An anode electrode 1114 shown in FIG. 12D is used to capture an emission current Ie emitted from the surface conduction electron-emitting device. The anode electrode 1114 is connected to a DC high voltage power supply 1115 and an ammeter 1116 (the substrate is referred to as a substrate). When the activation process is performed after the 1101 is incorporated in the display panel, the phosphor screen of the display panel is used as the anode electrode 1114.)
[0161]
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. 105 (b) shows an example of the emission current Ie measured by the ammeter 1116. When the pulse voltage is started to be applied from the activation power supply 1112, the emission current Ie increases with the passage of time, but eventually saturates. 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.
[0162]
Note 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.
[0163]
As described above, the planar type surface conduction electron-emitting device shown in FIG.
(Vertical type surface conduction electron-emitting device)
Next, another typical configuration of a surface conduction electron-emitting device in which an electron-emitting portion or its periphery is formed of a fine particle film, that is, a configuration of a vertical surface conduction electron-emitting device will be described.
[0164]
FIG. 15 is a schematic cross-sectional view for explaining a basic structure of a vertical type. In the figure, 1201 is a substrate, 1202 and 1203 are element electrodes, 1206 is a step forming member, and 1204 is a conductive layer using a fine particle film. Reference numeral 1205 denotes an electron-emitting portion formed by an energization forming process, and 1213 denotes a thin film formed by an energization activation process.
[0165]
The vertical type differs from the flat type described above in that one of the element electrodes (1202) is provided on the step forming member 1206, and the conductive thin film 1204 covers the side surface of the step forming member 1206. It is in the point. Therefore, the element electrode interval L in the planar type shown in FIG. 23 is set as the step height Ls of the step forming member 1206 in the vertical type. Note that for the substrate 1201, the element electrodes 1202 and 1203, and the conductive thin film 1204 using a fine particle film, the materials listed in the description of the planar type can be similarly used. In addition, the step forming member 1206 includes, for example, SiO 2₂An electrically insulating material such as
[0166]
Next, a method of manufacturing a vertical surface conduction electron-emitting device will be described. FIGS. 16A to 16F are cross-sectional views for explaining a manufacturing process, and the notation of each member is the same as that in FIG.
[0167]
1) First, as shown in FIG. 16A, an element electrode 1203 is formed on a substrate 1201.
[0168]
2) Next, as shown in FIG. 2B, an insulating layer for forming a step forming member is laminated. The insulating layer is made of, for example, SiO₂May be stacked by a sputtering method, but another film forming method such as a vacuum evaporation method or a printing method may be used.
[0169]
3) Next, as shown in FIG. 3C, an element electrode 1202 is formed on the insulating layer.
[0170]
4) Next, as shown in FIG. 4D, a part of the insulating layer is removed by using, for example, an etching method to expose the element electrode 1203.
[0171]
5) Next, as shown in FIG. 5E, a conductive thin film 1204 using a fine particle film is formed. For the formation, as in the case of the flat type, a film forming technique such as a coating method may be used.
[0172]
6) Next, as in the case of the planar type, the energization forming process is performed to form an electron emission portion (the same process as the planar type energization forming process described with reference to FIG. 12C may be performed). .).
[0173]
7) Next, in the same manner as in the case of the planar type, the energization activation process is performed to deposit carbon or a carbon compound in the vicinity of the electron emission portion (the planar energization activation process described with reference to FIG. The same processing as described above may be performed.).
[0174]
As described above, the vertical surface conduction electron-emitting device shown in FIG.
(Characteristics of surface conduction electron-emitting device used for display device)
The device configuration and the manufacturing method of the planar and vertical surface conduction electron-emitting devices have been described above. Next, the characteristics of the devices used in the display device will be described.
[0175]
FIG. 17 shows typical examples of (emission current Ie) versus (element applied voltage Vf) characteristics and (element current If) versus (element applied voltage Vf) characteristics of the elements used in the display device. Note that the emission current Ie is significantly smaller than the device current If, and it is difficult to show them on the same scale. In addition, these characteristics are changed by changing design parameters such as the size and shape of the device. Therefore, each of the two graphs is shown in arbitrary units.
[0176]
The element used for the display device has the following three characteristics regarding the emission current Ie.
[0177]
First, the emission current Ie sharply increases when a voltage higher than a certain voltage (this is called a threshold voltage Vth) or more is applied to the element. On the other hand, when the voltage is lower than the threshold voltage Vth, the emission current Ie hardly increases. Not detected.
[0178]
That is, the non-linear element has a clear threshold voltage Vth with respect to the emission current Ie.
[0179]
Second, since the emission current Ie changes depending on the voltage Vf applied to the element, the magnitude of the emission current Ie can be controlled by the voltage Vf.
[0180]
Third, since the response speed of the current Ie emitted from the element with respect to the voltage Vf applied to the element is high, the amount of charge of electrons emitted from the element can be controlled by the length of time during which the voltage Vf is applied.
[0181]
Because of the above characteristics, the surface conduction electron-emitting device can be suitably used for a display device. For example, in a display device in which a large number of elements are provided corresponding to pixels of a display screen, display can be performed by sequentially scanning the display screen by using the first characteristic. 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.
[0182]
Further, by using the second characteristic or the third characteristic, the light emission luminance can be controlled, so that gradation display can be performed.
(Structure of a multi-electron beam source with many elements wired in a simple matrix)
Next, the structure of a multi-electron beam source in which the above-described surface-conduction emission devices are arranged on a substrate and arranged in a simple matrix will be described.
[0183]
FIG. 18 is a plan view of the multi-electron beam source used for the display panel of FIG. On the substrate, surface conduction type emission elements similar to those shown in FIG. 11 are arranged, and these elements are wired in a simple matrix by row-direction wiring electrodes 1003 and column-direction wiring electrodes 1004. An insulating layer (not shown) is formed between the electrodes at the intersections of the row wiring electrodes 1003 and the column wiring electrodes 1004 to keep electrical insulation.
[0184]
FIG. 19 shows a cross section along the line BB 'in FIG.
[0185]
The multi-electron source having such a structure includes a row-direction wiring electrode 1003, a column-direction wiring electrode 1004, an inter-electrode insulating layer (not shown), a device electrode of a surface conduction electron-emitting device, and a conductive thin film. Is formed, power is 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.
[0186]
FIG. 20 shows a display configured so that image information provided from various image information sources such as television broadcasting can be displayed on a display panel using the surface conduction electron-emitting device described above as an electron beam source. It is a figure for showing an example of an apparatus.
[0187]
In the figure, 2100 is a display panel, 2101 is a display panel drive circuit, 2102 is a display controller, 2103 is a multiplexer, 2104 is a decoder, 2105 is an input / output interface circuit, 2106 is a CPU, 2107 is an image generation circuit, 2108 and 2109 and 2110 is an image memory interface circuit, 2111 is an image input interface circuit, 2112 and 2113 are TV signal receiving circuits, and 2114 is an input unit.
(When the present display device receives a signal including both video information and audio information, such as a television signal, it naturally reproduces audio simultaneously with the display of video. A description of circuits, speakers, and the like related to reception, separation, reproduction, processing, storage, and the like of audio information that is not directly related to features is omitted.)
Hereinafter, the function of each unit will be described along the flow of the image signal.
[0188]
First, the TV signal receiving circuit 2113 is a circuit for receiving a TV image signal transmitted using a wireless transmission system such as radio waves or spatial optical communication. The format of the received TV signal is not particularly limited, and may be, for example, various systems such as the NTSC system, the PAL system, and the SECAM system. Further, a TV signal (for example, a so-called high-definition TV including the MUSE system) composed of a larger number of scanning lines is suitable for taking advantage of the display panel suitable for increasing the area and the number of pixels. Signal source. The TV signal received by the TV signal receiving circuit 2113 is output to the decoder 2104.
[0189]
The TV signal receiving circuit 2112 is a circuit for receiving a TV image signal transmitted using a wired transmission system such as a coaxial cable or an optical fiber.
[0190]
As with the TV signal receiving circuit 2113, the type of the TV signal to be received is not particularly limited, and the TV signal received by this circuit is also output to the decoder 2104.
[0191]
Further, the image input interface circuit 2111 is a circuit for taking in an image signal supplied from an image input device such as a TV camera or an image reading scanner, and the taken image signal is outputted to the decoder 2104.
[0192]
The image memory interface circuit 2110 is a circuit for taking in an image signal stored in a video tape recorder (hereinafter abbreviated as VTR). The taken image signal is output to the decoder 2104.
[0193]
The image memory interface circuit 2109 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 2104.
[0194]
The image memory interface circuit 2108 is a circuit for taking in an image signal from a device storing still image data, such as a so-called still image disk, and the taken still image data is output to the decoder 2104.
[0195]
The input / output interface circuit 2105 is a circuit for connecting the present display device to an external computer, a computer network, or an output device such as a printer. In addition to inputting and outputting image data and character / graphic information, control signals and numerical data can be input and output between the CPU 2106 included in the display device and the outside in some cases.
[0196]
The image generation circuit 2107 also displays image data and character / graphic information input from outside via the input / output interface circuit 2105, or display image data based on image data or character / graphic information output from the CPU 2106. Is a circuit for generating. Within this circuit, for example, a rewritable memory for storing image data and character / graphic information, a read-only memory for storing image patterns corresponding to character codes, and a processor for image processing And other circuits necessary for generating an image.
[0197]
The display image data generated by this circuit is output to the decoder 2104, but may be output to an external computer network or printer via the input / output interface circuit 2105 in some cases.
[0198]
The CPU 2106 mainly performs operation control of the present display device and operations related to generation, selection, and editing of a display image.
[0199]
For example, a control signal is output to the multiplexer 2103, and image signals to be displayed on the display panel are appropriately selected or combined. In this case, a control signal is generated for the display panel controller 2102 in accordance with the image signal to be displayed, and the display frequency, the scanning method (for example, interlaced or non-interlaced), the number of scanning lines per screen, and the like are displayed. The operation of the device is appropriately controlled.
[0200]
In addition, image data and character / graphic information are directly output to the image generation circuit 2107, or an external computer or memory is accessed via the input / output interface circuit 2105 to output image data or character / graphic information. input.
[0201]
The CPU 2106 may, of course, be involved in work for other purposes. For example, it may be directly related to a function of generating and processing information, such as a personal computer or a word processor.
[0202]
Alternatively, it may be connected to an external computer network via the input / output interface circuit 2105 as described above, and work such as numerical calculation may be performed in cooperation with an external device.
[0203]
The input unit 2114 is for a user to input commands, programs, data, and the like to the CPU 2106. For example, in addition to a keyboard and a mouse, various input devices such as a joystick, a barcode reader, and a voice recognition device. Can be used.
[0204]
The decoder 2104 is a circuit for inversely converting various image signals input from the above 2107 to 2113 into three primary color signals or a luminance signal and an I signal and a Q signal. It is to be noted that the decoder 2104 desirably includes an image memory therein, as indicated by a dotted line in FIG. This is for handling a television signal that requires an image memory when performing inverse conversion, such as the MUSE method. Further, the provision of the image memory facilitates display of a still image, or enables image processing and editing including thinning, interpolation, enlargement, reduction, and synthesis of images in cooperation with the image generation circuit 2107 and the CPU 2106. This is because there is an advantage that it can be easily performed.
[0205]
The multiplexer 2103 selects a display image appropriately based on the control signal input from the CPU 2106. That is, the multiplexer 2103 selects a desired image signal from the inversely converted image signals input from the decoder 2104 and outputs the selected image signal to the drive circuit 2101. In that case, by switching and selecting image signals within one screen display time, it is also 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 television. .
[0206]
The display panel controller 2102 is a circuit for controlling the operation of the driving circuit 2101 based on the control signal input from the CPU 2106.
[0207]
First, as a signal related to a basic operation of the display panel, a signal for controlling an operation sequence of a power supply (not shown) for driving the display panel is output to the driving circuit 2101.
[0208]
In addition, a signal for controlling a screen display frequency and a scanning method (for example, interlaced or non-interlaced) is output to the drive circuit 2101 as a signal related to the display panel driving method.
[0209]
In some cases, a control signal related to image quality adjustment such as luminance, contrast, color tone, and sharpness of a display image may be output to the driving circuit 2101.
[0210]
The drive circuit 2101 is a circuit for generating a drive signal to be applied to the display panel 2100, and operates based on an image signal input from the multiplexer 2103 and a control signal input from the display panel controller 2102. Is what you do.
[0211]
The function of each unit has been described above. With the configuration illustrated in FIG. 200, the present display device can display image information input from various image information sources on the display panel 2100.
[0212]
That is, various image signals including television broadcasts are inversely converted by the decoder 2104, appropriately selected by the multiplexer 2103, and input to the drive circuit 2101. On the other hand, the display panel controller 2102 generates a control signal for controlling the operation of the driving circuit 2101 according to the image signal to be displayed. The drive circuit 2101 applies a drive signal to the display panel 2100 based on the image signal and the control signal.
[0213]
Thus, an image is displayed on display panel 2100. These series of operations are totally controlled by the CPU 2106.
[0214]
Further, in the present display device, not only the image information selected from a plurality of pieces of image information is displayed but also displayed by the involvement of the image memory incorporated in the decoder 2104, the image generation circuit 2107 and the CPU 2106. For image information, for example, image processing such as enlargement, reduction, rotation, movement, edge emphasis, thinning, interpolation, color conversion, image aspect ratio conversion, etc., synthesis, deletion, connection, replacement, insertion, etc. It is also possible to perform the first image editing. Although not specifically described in the description of the present embodiment, a dedicated circuit for processing and editing audio information may be provided as in the above-described image processing and image editing.
[0215]
Therefore, the present display device can be used for television broadcast display devices, video conference terminal devices, image editing devices for handling still images and moving images, computer terminal devices, office terminals including word processors, game machines, and the like. It is possible to have a single function, and it has a very wide range of applications for industrial or consumer use.
[0216]
FIG. 20 merely shows an example of the configuration of a display device using a display panel using a surface conduction electron-emitting device as an electron beam source, and it is needless to say that the present invention is not limited to this. For example, among the components shown in FIG. 20, circuits relating to functions that are unnecessary for the intended purpose may be omitted. Conversely, additional components may be added depending on the purpose of use. For example, when the present display device is applied to a videophone, it is preferable to add a transmission / reception circuit including a television camera, an audio microphone, a lighting device, and a modem to the components.
[0217]
In the present display device, in particular, since the display panel using the surface conduction electron-emitting device as the electron beam source can be easily made thin, the depth of the entire display device can be reduced. In addition, the display panel using surface conduction electron-emitting devices as the electron beam source can easily enlarge the screen, and has high brightness and excellent viewing angle characteristics. It is possible to display well.
[0218]
【The invention's effect】
According to the first configuration of the present invention, it is possible to display an image having good tone reproduction characteristics regardless of the saturation phenomenon of the phosphor. Further, by performing the correction for each emission color, it is possible to display an image having good color reproduction characteristics.
[0219]
According to the second configuration of the present invention, even when the display device receives a plurality of types of input signals such as a TV signal and a PC image signal, an image display having good tone reproduction and color reproduction characteristics can be obtained. It becomes possible.
[0220]
According to the third configuration of the present invention, even when the display device performs the so-called ABL control for reducing the average luminance of the entire screen even if the peak luminance is large in order to suppress power consumption, good gradation reproduction and color reproduction can be achieved. Image display having reproducibility can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram of a driving circuit of a surface conduction electron emission display (SED) panel.
FIG. 2 is an NTSC-RGB decoder section.
FIG. 3 is a timing generator.
FIG. 4 is an analog processing unit.
FIG. 5 is a time chart for explaining an operation of a drive circuit of a surface conduction electron emission display (SED) panel.
FIG. 6 is a graph showing gamma restoring characteristics;
FIG. 7 is a graph showing emission luminance characteristics of the SED panel.
FIG. 8 is a block diagram of an input signal selector.
FIG. 9 is a perspective view of an SED display panel.
FIG. 10 is an arrangement diagram of a phosphor matrix.
FIG. 11 is a plan view and a sectional view of a surface conduction electron-emitting device.
FIG. 12 is a manufacturing process diagram of the surface conduction electron-emitting device.
FIG. 13 is a diagram of a forming voltage waveform.
FIG. 14 is an activation voltage waveform and emission current waveform diagram.
FIG. 15 is a sectional view of a vertical surface conduction electron-emitting device.
FIG. 16 is a manufacturing process diagram of a vertical surface conduction electron-emitting device.
FIG. 17 is a graph showing emission current characteristics of a surface conduction electron-emitting device.
FIG. 18 is an electron source using simple matrix wiring.
FIG. 19 is a sectional view taken along line B-B ′ of the electron source formed by simple matrix wiring.
FIG. 20 is a block diagram of a surface conduction electron emission display system.
FIG. 21 is a plan view of a conventional surface conduction electron-emitting device.
FIG. 22 is a cross-sectional view of a conventional field emission electron-emitting device.
FIG. 23 is a sectional view of a conventional MIM type electron-emitting device.
FIG. 24 is a matrix arrangement diagram of a conventional MIM-type electron-emitting device.
[Explanation of symbols]
P1 NTSC-RGB decoder
P2 timing generator
P3 Analog processing unit
P2000 display panel
P3000 Row direction driving means
P1101, P1107 Shift register
1001 electron source substrate
1005 Rear plate
1006 Frame
1010 face plate
1101 substrate
1102, 1103 Device electrode
1104 Conductive thin film
1105 Electron emission unit

Claims (7)

An electron-emitting device connected to a row wiring and a column wiring arranged in a matrix; a phosphor that emits light by receiving electrons emitted from the electron-emitting device; and a converted image signal that converts an input image signal. An image display device comprising: an image signal conversion unit that outputs an image signal; and a modulation unit that modulates an irradiation time of an electron beam emitted from the electron-emitting device based on the converted image signal.
The image signal converting means restores the input image signal obtained by gamma correcting the original signal for a cathode ray tube to the original signal,
The restored the original signal, and outputs the converted to the converted image signal to said original signal to said correcting the nonlinearity of the phosphor emission amount linearly the converted image signal to said phosphor emission amount characteristics,
The image display device, wherein the modulation unit modulates a pulse width of a voltage applied to the column wiring based on the converted image signal. The non-linearity of the original signal versus the phosphor emission luminance is a characteristic that becomes an upwardly convex curve when the original signal is set on the horizontal axis and the phosphor emission luminance is set on the vertical axis. Image display device. Image determination means for determining the type of the input image signal,
Brightness control means for performing brightness control based on the output of the image determination means,
The image display device according to claim 1, wherein the image signal conversion unit converts the input image signal based on an output of the image determination unit and outputs a converted image signal. 4. The image display device according to claim 3, wherein said brightness control means performs brightness control by changing a maximum potential applied to said column wiring or a scanning selection potential applied to said row wiring. Has an average value detection detemir stage for detecting an average input brightness level of the input image signal, and a brightness control means for performing brightness control on the basis of the average input brightness level,
The image display device according to claim 1, wherein the image signal conversion unit converts the input image signal based on an output of the average value detection unit and outputs a converted image signal. 3. The image display device according to claim 2, wherein the image signal conversion means includes a type conversion table memory for generating the converted image signal from the input image signal for each type of the input image. An electron-emitting device connected to a row wiring and a column wiring arranged in a matrix; a phosphor that emits light by receiving electrons emitted from the electron-emitting device; and a converted image signal that converts an input image signal. An image display device comprising: an image signal conversion unit that outputs an image signal; and a modulation unit that modulates an irradiation time of an electron beam emitted from the electron-emitting device based on the converted image signal.
The image signal conversion means, the conversion of the signal by the image signal conversion means,
The input image signal obtained by correcting the original signal for a cathode ray tube, a correction performed to approach the original signal,
And further correcting the signal corrected to approach the original signal. Correcting the characteristics of the light emission amount of the phosphor caused by electron emission by the drive signal with respect to the drive signal when input to the emission element;
The image display device, wherein the modulation unit modulates a pulse width of a voltage applied to the column wiring based on the drive signal.

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